/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ #ifndef __LINUX_BPF_H__ #define __LINUX_BPF_H__ #include <linux/types.h> #include <linux/bpf_common.h> /* Extended instruction set based on top of classic BPF */ /* instruction classes */ #define BPF_JMP32 0x06 /* jmp mode in word width */ #define BPF_ALU64 0x07 /* alu mode in double word width */ /* ld/ldx fields */ #define BPF_DW 0x18 /* double word (64-bit) */ #define BPF_XADD 0xc0 /* exclusive add */ /* alu/jmp fields */ #define BPF_MOV 0xb0 /* mov reg to reg */ #define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */ /* change endianness of a register */ #define BPF_END 0xd0 /* flags for endianness conversion: */ #define BPF_TO_LE 0x00 /* convert to little-endian */ #define BPF_TO_BE 0x08 /* convert to big-endian */ #define BPF_FROM_LE BPF_TO_LE #define BPF_FROM_BE BPF_TO_BE /* jmp encodings */ #define BPF_JNE 0x50 /* jump != */ #define BPF_JLT 0xa0 /* LT is unsigned, '<' */ #define BPF_JLE 0xb0 /* LE is unsigned, '<=' */ #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */ #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */ #define BPF_JSLT 0xc0 /* SLT is signed, '<' */ #define BPF_JSLE 0xd0 /* SLE is signed, '<=' */ #define BPF_CALL 0x80 /* function call */ #define BPF_EXIT 0x90 /* function return */ /* Register numbers */ enum { BPF_REG_0 = 0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5, BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9, BPF_REG_10, __MAX_BPF_REG, }; /* BPF has 10 general purpose 64-bit registers and stack frame. */ #define MAX_BPF_REG __MAX_BPF_REG struct bpf_insn { __u8 code; /* opcode */ __u8 dst_reg:4; /* dest register */ __u8 src_reg:4; /* source register */ __s16 off; /* signed offset */ __s32 imm; /* signed immediate constant */ }; /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */ struct bpf_lpm_trie_key { __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */ __u8 data[0]; /* Arbitrary size */ }; struct bpf_cgroup_storage_key { __u64 cgroup_inode_id; /* cgroup inode id */ __u32 attach_type; /* program attach type */ }; union bpf_iter_link_info { struct { __u32 map_fd; } map; }; /* BPF syscall commands, see bpf(2) man-page for details. */ enum bpf_cmd { BPF_MAP_CREATE, BPF_MAP_LOOKUP_ELEM, BPF_MAP_UPDATE_ELEM, BPF_MAP_DELETE_ELEM, BPF_MAP_GET_NEXT_KEY, BPF_PROG_LOAD, BPF_OBJ_PIN, BPF_OBJ_GET, BPF_PROG_ATTACH, BPF_PROG_DETACH, BPF_PROG_TEST_RUN, BPF_PROG_GET_NEXT_ID, BPF_MAP_GET_NEXT_ID, BPF_PROG_GET_FD_BY_ID, BPF_MAP_GET_FD_BY_ID, BPF_OBJ_GET_INFO_BY_FD, BPF_PROG_QUERY, BPF_RAW_TRACEPOINT_OPEN, BPF_BTF_LOAD, BPF_BTF_GET_FD_BY_ID, BPF_TASK_FD_QUERY, BPF_MAP_LOOKUP_AND_DELETE_ELEM, BPF_MAP_FREEZE, BPF_BTF_GET_NEXT_ID, BPF_MAP_LOOKUP_BATCH, BPF_MAP_LOOKUP_AND_DELETE_BATCH, BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, BPF_LINK_CREATE, BPF_LINK_UPDATE, BPF_LINK_GET_FD_BY_ID, BPF_LINK_GET_NEXT_ID, BPF_ENABLE_STATS, BPF_ITER_CREATE, BPF_LINK_DETACH, BPF_PROG_BIND_MAP, }; enum bpf_map_type { BPF_MAP_TYPE_UNSPEC, BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PROG_ARRAY, BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_MAP_TYPE_PERCPU_HASH, BPF_MAP_TYPE_PERCPU_ARRAY, BPF_MAP_TYPE_STACK_TRACE, BPF_MAP_TYPE_CGROUP_ARRAY, BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH, BPF_MAP_TYPE_LPM_TRIE, BPF_MAP_TYPE_ARRAY_OF_MAPS, BPF_MAP_TYPE_HASH_OF_MAPS, BPF_MAP_TYPE_DEVMAP, BPF_MAP_TYPE_SOCKMAP, BPF_MAP_TYPE_CPUMAP, BPF_MAP_TYPE_XSKMAP, BPF_MAP_TYPE_SOCKHASH, BPF_MAP_TYPE_CGROUP_STORAGE, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, BPF_MAP_TYPE_QUEUE, BPF_MAP_TYPE_STACK, BPF_MAP_TYPE_SK_STORAGE, BPF_MAP_TYPE_DEVMAP_HASH, BPF_MAP_TYPE_STRUCT_OPS, BPF_MAP_TYPE_RINGBUF, BPF_MAP_TYPE_INODE_STORAGE, }; /* Note that tracing related programs such as * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT} * are not subject to a stable API since kernel internal data * structures can change from release to release and may * therefore break existing tracing BPF programs. Tracing BPF * programs correspond to /a/ specific kernel which is to be * analyzed, and not /a/ specific kernel /and/ all future ones. */ enum bpf_prog_type { BPF_PROG_TYPE_UNSPEC, BPF_PROG_TYPE_SOCKET_FILTER, BPF_PROG_TYPE_KPROBE, BPF_PROG_TYPE_SCHED_CLS, BPF_PROG_TYPE_SCHED_ACT, BPF_PROG_TYPE_TRACEPOINT, BPF_PROG_TYPE_XDP, BPF_PROG_TYPE_PERF_EVENT, BPF_PROG_TYPE_CGROUP_SKB, BPF_PROG_TYPE_CGROUP_SOCK, BPF_PROG_TYPE_LWT_IN, BPF_PROG_TYPE_LWT_OUT, BPF_PROG_TYPE_LWT_XMIT, BPF_PROG_TYPE_SOCK_OPS, BPF_PROG_TYPE_SK_SKB, BPF_PROG_TYPE_CGROUP_DEVICE, BPF_PROG_TYPE_SK_MSG, BPF_PROG_TYPE_RAW_TRACEPOINT, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_PROG_TYPE_LWT_SEG6LOCAL, BPF_PROG_TYPE_LIRC_MODE2, BPF_PROG_TYPE_SK_REUSEPORT, BPF_PROG_TYPE_FLOW_DISSECTOR, BPF_PROG_TYPE_CGROUP_SYSCTL, BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, BPF_PROG_TYPE_CGROUP_SOCKOPT, BPF_PROG_TYPE_TRACING, BPF_PROG_TYPE_STRUCT_OPS, BPF_PROG_TYPE_EXT, BPF_PROG_TYPE_LSM, BPF_PROG_TYPE_SK_LOOKUP, }; enum bpf_attach_type { BPF_CGROUP_INET_INGRESS, BPF_CGROUP_INET_EGRESS, BPF_CGROUP_INET_SOCK_CREATE, BPF_CGROUP_SOCK_OPS, BPF_SK_SKB_STREAM_PARSER, BPF_SK_SKB_STREAM_VERDICT, BPF_CGROUP_DEVICE, BPF_SK_MSG_VERDICT, BPF_CGROUP_INET4_BIND, BPF_CGROUP_INET6_BIND, BPF_CGROUP_INET4_CONNECT, BPF_CGROUP_INET6_CONNECT, BPF_CGROUP_INET4_POST_BIND, BPF_CGROUP_INET6_POST_BIND, BPF_CGROUP_UDP4_SENDMSG, BPF_CGROUP_UDP6_SENDMSG, BPF_LIRC_MODE2, BPF_FLOW_DISSECTOR, BPF_CGROUP_SYSCTL, BPF_CGROUP_UDP4_RECVMSG, BPF_CGROUP_UDP6_RECVMSG, BPF_CGROUP_GETSOCKOPT, BPF_CGROUP_SETSOCKOPT, BPF_TRACE_RAW_TP, BPF_TRACE_FENTRY, BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, BPF_LSM_MAC, BPF_TRACE_ITER, BPF_CGROUP_INET4_GETPEERNAME, BPF_CGROUP_INET6_GETPEERNAME, BPF_CGROUP_INET4_GETSOCKNAME, BPF_CGROUP_INET6_GETSOCKNAME, BPF_XDP_DEVMAP, BPF_CGROUP_INET_SOCK_RELEASE, BPF_XDP_CPUMAP, BPF_SK_LOOKUP, BPF_XDP, __MAX_BPF_ATTACH_TYPE }; #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE enum bpf_link_type { BPF_LINK_TYPE_UNSPEC = 0, BPF_LINK_TYPE_RAW_TRACEPOINT = 1, BPF_LINK_TYPE_TRACING = 2, BPF_LINK_TYPE_CGROUP = 3, BPF_LINK_TYPE_ITER = 4, BPF_LINK_TYPE_NETNS = 5, BPF_LINK_TYPE_XDP = 6, MAX_BPF_LINK_TYPE, }; /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. * * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program, * the program in this cgroup yields to sub-cgroup program. * * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program, * that cgroup program gets run in addition to the program in this cgroup. * * Only one program is allowed to be attached to a cgroup with * NONE or BPF_F_ALLOW_OVERRIDE flag. * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will * release old program and attach the new one. Attach flags has to match. * * Multiple programs are allowed to be attached to a cgroup with * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order * (those that were attached first, run first) * The programs of sub-cgroup are executed first, then programs of * this cgroup and then programs of parent cgroup. * When children program makes decision (like picking TCP CA or sock bind) * parent program has a chance to override it. * * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of * programs for a cgroup. Though it's possible to replace an old program at * any position by also specifying BPF_F_REPLACE flag and position itself in * replace_bpf_fd attribute. Old program at this position will be released. * * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups. * A cgroup with NONE doesn't allow any programs in sub-cgroups. * Ex1: * cgrp1 (MULTI progs A, B) -> * cgrp2 (OVERRIDE prog C) -> * cgrp3 (MULTI prog D) -> * cgrp4 (OVERRIDE prog E) -> * cgrp5 (NONE prog F) * the event in cgrp5 triggers execution of F,D,A,B in that order. * if prog F is detached, the execution is E,D,A,B * if prog F and D are detached, the execution is E,A,B * if prog F, E and D are detached, the execution is C,A,B * * All eligible programs are executed regardless of return code from * earlier programs. */ #define BPF_F_ALLOW_OVERRIDE (1U << 0) #define BPF_F_ALLOW_MULTI (1U << 1) #define BPF_F_REPLACE (1U << 2) /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the * verifier will perform strict alignment checking as if the kernel * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set, * and NET_IP_ALIGN defined to 2. */ #define BPF_F_STRICT_ALIGNMENT (1U << 0) /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the * verifier will allow any alignment whatsoever. On platforms * with strict alignment requirements for loads ands stores (such * as sparc and mips) the verifier validates that all loads and * stores provably follow this requirement. This flag turns that * checking and enforcement off. * * It is mostly used for testing when we want to validate the * context and memory access aspects of the verifier, but because * of an unaligned access the alignment check would trigger before * the one we are interested in. */ #define BPF_F_ANY_ALIGNMENT (1U << 1) /* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose. * Verifier does sub-register def/use analysis and identifies instructions whose * def only matters for low 32-bit, high 32-bit is never referenced later * through implicit zero extension. Therefore verifier notifies JIT back-ends * that it is safe to ignore clearing high 32-bit for these instructions. This * saves some back-ends a lot of code-gen. However such optimization is not * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends * hence hasn't used verifier's analysis result. But, we really want to have a * way to be able to verify the correctness of the described optimization on * x86_64 on which testsuites are frequently exercised. * * So, this flag is introduced. Once it is set, verifier will randomize high * 32-bit for those instructions who has been identified as safe to ignore them. * Then, if verifier is not doing correct analysis, such randomization will * regress tests to expose bugs. */ #define BPF_F_TEST_RND_HI32 (1U << 2) /* The verifier internal test flag. Behavior is undefined */ #define BPF_F_TEST_STATE_FREQ (1U << 3) /* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will * restrict map and helper usage for such programs. Sleepable BPF programs can * only be attached to hooks where kernel execution context allows sleeping. * Such programs are allowed to use helpers that may sleep like * bpf_copy_from_user(). */ #define BPF_F_SLEEPABLE (1U << 4) /* When BPF ldimm64's insn[0].src_reg != 0 then this can have * the following extensions: * * insn[0].src_reg: BPF_PSEUDO_MAP_FD * insn[0].imm: map fd * insn[1].imm: 0 * insn[0].off: 0 * insn[1].off: 0 * ldimm64 rewrite: address of map * verifier type: CONST_PTR_TO_MAP */ #define BPF_PSEUDO_MAP_FD 1 /* insn[0].src_reg: BPF_PSEUDO_MAP_VALUE * insn[0].imm: map fd * insn[1].imm: offset into value * insn[0].off: 0 * insn[1].off: 0 * ldimm64 rewrite: address of map[0]+offset * verifier type: PTR_TO_MAP_VALUE */ #define BPF_PSEUDO_MAP_VALUE 2 /* insn[0].src_reg: BPF_PSEUDO_BTF_ID * insn[0].imm: kernel btd id of VAR * insn[1].imm: 0 * insn[0].off: 0 * insn[1].off: 0 * ldimm64 rewrite: address of the kernel variable * verifier type: PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var * is struct/union. */ #define BPF_PSEUDO_BTF_ID 3 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative * offset to another bpf function */ #define BPF_PSEUDO_CALL 1 /* flags for BPF_MAP_UPDATE_ELEM command */ enum { BPF_ANY = 0, /* create new element or update existing */ BPF_NOEXIST = 1, /* create new element if it didn't exist */ BPF_EXIST = 2, /* update existing element */ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */ }; /* flags for BPF_MAP_CREATE command */ enum { BPF_F_NO_PREALLOC = (1U << 0), /* Instead of having one common LRU list in the * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list * which can scale and perform better. * Note, the LRU nodes (including free nodes) cannot be moved * across different LRU lists. */ BPF_F_NO_COMMON_LRU = (1U << 1), /* Specify numa node during map creation */ BPF_F_NUMA_NODE = (1U << 2), /* Flags for accessing BPF object from syscall side. */ BPF_F_RDONLY = (1U << 3), BPF_F_WRONLY = (1U << 4), /* Flag for stack_map, store build_id+offset instead of pointer */ BPF_F_STACK_BUILD_ID = (1U << 5), /* Zero-initialize hash function seed. This should only be used for testing. */ BPF_F_ZERO_SEED = (1U << 6), /* Flags for accessing BPF object from program side. */ BPF_F_RDONLY_PROG = (1U << 7), BPF_F_WRONLY_PROG = (1U << 8), /* Clone map from listener for newly accepted socket */ BPF_F_CLONE = (1U << 9), /* Enable memory-mapping BPF map */ BPF_F_MMAPABLE = (1U << 10), /* Share perf_event among processes */ BPF_F_PRESERVE_ELEMS = (1U << 11), /* Create a map that is suitable to be an inner map with dynamic max entries */ BPF_F_INNER_MAP = (1U << 12), }; /* Flags for BPF_PROG_QUERY. */ /* Query effective (directly attached + inherited from ancestor cgroups) * programs that will be executed for events within a cgroup. * attach_flags with this flag are returned only for directly attached programs. */ #define BPF_F_QUERY_EFFECTIVE (1U << 0) /* Flags for BPF_PROG_TEST_RUN */ /* If set, run the test on the cpu specified by bpf_attr.test.cpu */ #define BPF_F_TEST_RUN_ON_CPU (1U << 0) /* type for BPF_ENABLE_STATS */ enum bpf_stats_type { /* enabled run_time_ns and run_cnt */ BPF_STATS_RUN_TIME = 0, }; enum bpf_stack_build_id_status { /* user space need an empty entry to identify end of a trace */ BPF_STACK_BUILD_ID_EMPTY = 0, /* with valid build_id and offset */ BPF_STACK_BUILD_ID_VALID = 1, /* couldn't get build_id, fallback to ip */ BPF_STACK_BUILD_ID_IP = 2, }; #define BPF_BUILD_ID_SIZE 20 struct bpf_stack_build_id { __s32 status; unsigned char build_id[BPF_BUILD_ID_SIZE]; union { __u64 offset; __u64 ip; }; }; #define BPF_OBJ_NAME_LEN 16U union bpf_attr { struct { /* anonymous struct used by BPF_MAP_CREATE command */ __u32 map_type; /* one of enum bpf_map_type */ __u32 key_size; /* size of key in bytes */ __u32 value_size; /* size of value in bytes */ __u32 max_entries; /* max number of entries in a map */ __u32 map_flags; /* BPF_MAP_CREATE related * flags defined above. */ __u32 inner_map_fd; /* fd pointing to the inner map */ __u32 numa_node; /* numa node (effective only if * BPF_F_NUMA_NODE is set). */ char map_name[BPF_OBJ_NAME_LEN]; __u32 map_ifindex; /* ifindex of netdev to create on */ __u32 btf_fd; /* fd pointing to a BTF type data */ __u32 btf_key_type_id; /* BTF type_id of the key */ __u32 btf_value_type_id; /* BTF type_id of the value */ __u32 btf_vmlinux_value_type_id;/* BTF type_id of a kernel- * struct stored as the * map value */ }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ __u32 map_fd; __aligned_u64 key; union { __aligned_u64 value; __aligned_u64 next_key; }; __u64 flags; }; struct { /* struct used by BPF_MAP_*_BATCH commands */ __aligned_u64 in_batch; /* start batch, * NULL to start from beginning */ __aligned_u64 out_batch; /* output: next start batch */ __aligned_u64 keys; __aligned_u64 values; __u32 count; /* input/output: * input: # of key/value * elements * output: # of filled elements */ __u32 map_fd; __u64 elem_flags; __u64 flags; } batch; struct { /* anonymous struct used by BPF_PROG_LOAD command */ __u32 prog_type; /* one of enum bpf_prog_type */ __u32 insn_cnt; __aligned_u64 insns; __aligned_u64 license; __u32 log_level; /* verbosity level of verifier */ __u32 log_size; /* size of user buffer */ __aligned_u64 log_buf; /* user supplied buffer */ __u32 kern_version; /* not used */ __u32 prog_flags; char prog_name[BPF_OBJ_NAME_LEN]; __u32 prog_ifindex; /* ifindex of netdev to prep for */ /* For some prog types expected attach type must be known at * load time to verify attach type specific parts of prog * (context accesses, allowed helpers, etc). */ __u32 expected_attach_type; __u32 prog_btf_fd; /* fd pointing to BTF type data */ __u32 func_info_rec_size; /* userspace bpf_func_info size */ __aligned_u64 func_info; /* func info */ __u32 func_info_cnt; /* number of bpf_func_info records */ __u32 line_info_rec_size; /* userspace bpf_line_info size */ __aligned_u64 line_info; /* line info */ __u32 line_info_cnt; /* number of bpf_line_info records */ __u32 attach_btf_id; /* in-kernel BTF type id to attach to */ __u32 attach_prog_fd; /* 0 to attach to vmlinux */ }; struct { /* anonymous struct used by BPF_OBJ_* commands */ __aligned_u64 pathname; __u32 bpf_fd; __u32 file_flags; }; struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */ __u32 target_fd; /* container object to attach to */ __u32 attach_bpf_fd; /* eBPF program to attach */ __u32 attach_type; __u32 attach_flags; __u32 replace_bpf_fd; /* previously attached eBPF * program to replace if * BPF_F_REPLACE is used */ }; struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */ __u32 prog_fd; __u32 retval; __u32 data_size_in; /* input: len of data_in */ __u32 data_size_out; /* input/output: len of data_out * returns ENOSPC if data_out * is too small. */ __aligned_u64 data_in; __aligned_u64 data_out; __u32 repeat; __u32 duration; __u32 ctx_size_in; /* input: len of ctx_in */ __u32 ctx_size_out; /* input/output: len of ctx_out * returns ENOSPC if ctx_out * is too small. */ __aligned_u64 ctx_in; __aligned_u64 ctx_out; __u32 flags; __u32 cpu; } test; struct { /* anonymous struct used by BPF_*_GET_*_ID */ union { __u32 start_id; __u32 prog_id; __u32 map_id; __u32 btf_id; __u32 link_id; }; __u32 next_id; __u32 open_flags; }; struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */ __u32 bpf_fd; __u32 info_len; __aligned_u64 info; } info; struct { /* anonymous struct used by BPF_PROG_QUERY command */ __u32 target_fd; /* container object to query */ __u32 attach_type; __u32 query_flags; __u32 attach_flags; __aligned_u64 prog_ids; __u32 prog_cnt; } query; struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */ __u64 name; __u32 prog_fd; } raw_tracepoint; struct { /* anonymous struct for BPF_BTF_LOAD */ __aligned_u64 btf; __aligned_u64 btf_log_buf; __u32 btf_size; __u32 btf_log_size; __u32 btf_log_level; }; struct { __u32 pid; /* input: pid */ __u32 fd; /* input: fd */ __u32 flags; /* input: flags */ __u32 buf_len; /* input/output: buf len */ __aligned_u64 buf; /* input/output: * tp_name for tracepoint * symbol for kprobe * filename for uprobe */ __u32 prog_id; /* output: prod_id */ __u32 fd_type; /* output: BPF_FD_TYPE_* */ __u64 probe_offset; /* output: probe_offset */ __u64 probe_addr; /* output: probe_addr */ } task_fd_query; struct { /* struct used by BPF_LINK_CREATE command */ __u32 prog_fd; /* eBPF program to attach */ union { __u32 target_fd; /* object to attach to */ __u32 target_ifindex; /* target ifindex */ }; __u32 attach_type; /* attach type */ __u32 flags; /* extra flags */ union { __u32 target_btf_id; /* btf_id of target to attach to */ struct { __aligned_u64 iter_info; /* extra bpf_iter_link_info */ __u32 iter_info_len; /* iter_info length */ }; }; } link_create; struct { /* struct used by BPF_LINK_UPDATE command */ __u32 link_fd; /* link fd */ /* new program fd to update link with */ __u32 new_prog_fd; __u32 flags; /* extra flags */ /* expected link's program fd; is specified only if * BPF_F_REPLACE flag is set in flags */ __u32 old_prog_fd; } link_update; struct { __u32 link_fd; } link_detach; struct { /* struct used by BPF_ENABLE_STATS command */ __u32 type; } enable_stats; struct { /* struct used by BPF_ITER_CREATE command */ __u32 link_fd; __u32 flags; } iter_create; struct { /* struct used by BPF_PROG_BIND_MAP command */ __u32 prog_fd; __u32 map_fd; __u32 flags; /* extra flags */ } prog_bind_map; } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF * developers about the multiple available eBPF helper functions. It can be * parsed and used to produce a manual page. The workflow is the following, * and requires the rst2man utility: * * $ ./scripts/bpf_helpers_doc.py \ * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 * $ man /tmp/bpf-helpers.7 * * Note that in order to produce this external documentation, some RST * formatting is used in the descriptions to get "bold" and "italics" in * manual pages. Also note that the few trailing white spaces are * intentional, removing them would break paragraphs for rst2man. * * Start of BPF helper function descriptions: * * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) * Description * Perform a lookup in *map* for an entry associated to *key*. * Return * Map value associated to *key*, or **NULL** if no entry was * found. * * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) * Description * Add or update the value of the entry associated to *key* in * *map* with *value*. *flags* is one of: * * **BPF_NOEXIST** * The entry for *key* must not exist in the map. * **BPF_EXIST** * The entry for *key* must already exist in the map. * **BPF_ANY** * No condition on the existence of the entry for *key*. * * Flag value **BPF_NOEXIST** cannot be used for maps of types * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all * elements always exist), the helper would return an error. * Return * 0 on success, or a negative error in case of failure. * * long bpf_map_delete_elem(struct bpf_map *map, const void *key) * Description * Delete entry with *key* from *map*. * Return * 0 on success, or a negative error in case of failure. * * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr) * Description * For tracing programs, safely attempt to read *size* bytes from * kernel space address *unsafe_ptr* and store the data in *dst*. * * Generally, use **bpf_probe_read_user**\ () or * **bpf_probe_read_kernel**\ () instead. * Return * 0 on success, or a negative error in case of failure. * * u64 bpf_ktime_get_ns(void) * Description * Return the time elapsed since system boot, in nanoseconds. * Does not include time the system was suspended. * See: **clock_gettime**\ (**CLOCK_MONOTONIC**) * Return * Current *ktime*. * * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...) * Description * This helper is a "printk()-like" facility for debugging. It * prints a message defined by format *fmt* (of size *fmt_size*) * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if * available. It can take up to three additional **u64** * arguments (as an eBPF helpers, the total number of arguments is * limited to five). * * Each time the helper is called, it appends a line to the trace. * Lines are discarded while *\/sys/kernel/debug/tracing/trace* is * open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this. * The format of the trace is customizable, and the exact output * one will get depends on the options set in * *\/sys/kernel/debug/tracing/trace_options* (see also the * *README* file under the same directory). However, it usually * defaults to something like: * * :: * * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg> * * In the above: * * * ``telnet`` is the name of the current task. * * ``470`` is the PID of the current task. * * ``001`` is the CPU number on which the task is * running. * * In ``.N..``, each character refers to a set of * options (whether irqs are enabled, scheduling * options, whether hard/softirqs are running, level of * preempt_disabled respectively). **N** means that * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED** * are set. * * ``419421.045894`` is a timestamp. * * ``0x00000001`` is a fake value used by BPF for the * instruction pointer register. * * ``<formatted msg>`` is the message formatted with * *fmt*. * * The conversion specifiers supported by *fmt* are similar, but * more limited than for printk(). They are **%d**, **%i**, * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**, * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size * of field, padding with zeroes, etc.) is available, and the * helper will return **-EINVAL** (but print nothing) if it * encounters an unknown specifier. * * Also, note that **bpf_trace_printk**\ () is slow, and should * only be used for debugging purposes. For this reason, a notice * block (spanning several lines) is printed to kernel logs and * states that the helper should not be used "for production use" * the first time this helper is used (or more precisely, when * **trace_printk**\ () buffers are allocated). For passing values * to user space, perf events should be preferred. * Return * The number of bytes written to the buffer, or a negative error * in case of failure. * * u32 bpf_get_prandom_u32(void) * Description * Get a pseudo-random number. * * From a security point of view, this helper uses its own * pseudo-random internal state, and cannot be used to infer the * seed of other random functions in the kernel. However, it is * essential to note that the generator used by the helper is not * cryptographically secure. * Return * A random 32-bit unsigned value. * * u32 bpf_get_smp_processor_id(void) * Description * Get the SMP (symmetric multiprocessing) processor id. Note that * all programs run with preemption disabled, which means that the * SMP processor id is stable during all the execution of the * program. * Return * The SMP id of the processor running the program. * * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags) * Description * Store *len* bytes from address *from* into the packet * associated to *skb*, at *offset*. *flags* are a combination of * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the * checksum for the packet after storing the bytes) and * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\ * **->swhash** and *skb*\ **->l4hash** to 0). * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size) * Description * Recompute the layer 3 (e.g. IP) checksum for the packet * associated to *skb*. Computation is incremental, so the helper * must know the former value of the header field that was * modified (*from*), the new value of this field (*to*), and the * number of bytes (2 or 4) for this field, stored in *size*. * Alternatively, it is possible to store the difference between * the previous and the new values of the header field in *to*, by * setting *from* and *size* to 0. For both methods, *offset* * indicates the location of the IP checksum within the packet. * * This helper works in combination with **bpf_csum_diff**\ (), * which does not update the checksum in-place, but offers more * flexibility and can handle sizes larger than 2 or 4 for the * checksum to update. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags) * Description * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the * packet associated to *skb*. Computation is incremental, so the * helper must know the former value of the header field that was * modified (*from*), the new value of this field (*to*), and the * number of bytes (2 or 4) for this field, stored on the lowest * four bits of *flags*. Alternatively, it is possible to store * the difference between the previous and the new values of the * header field in *to*, by setting *from* and the four lowest * bits of *flags* to 0. For both methods, *offset* indicates the * location of the IP checksum within the packet. In addition to * the size of the field, *flags* can be added (bitwise OR) actual * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and * for updates resulting in a null checksum the value is set to * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates * the checksum is to be computed against a pseudo-header. * * This helper works in combination with **bpf_csum_diff**\ (), * which does not update the checksum in-place, but offers more * flexibility and can handle sizes larger than 2 or 4 for the * checksum to update. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index) * Description * This special helper is used to trigger a "tail call", or in * other words, to jump into another eBPF program. The same stack * frame is used (but values on stack and in registers for the * caller are not accessible to the callee). This mechanism allows * for program chaining, either for raising the maximum number of * available eBPF instructions, or to execute given programs in * conditional blocks. For security reasons, there is an upper * limit to the number of successive tail calls that can be * performed. * * Upon call of this helper, the program attempts to jump into a * program referenced at index *index* in *prog_array_map*, a * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes * *ctx*, a pointer to the context. * * If the call succeeds, the kernel immediately runs the first * instruction of the new program. This is not a function call, * and it never returns to the previous program. If the call * fails, then the helper has no effect, and the caller continues * to run its subsequent instructions. A call can fail if the * destination program for the jump does not exist (i.e. *index* * is superior to the number of entries in *prog_array_map*), or * if the maximum number of tail calls has been reached for this * chain of programs. This limit is defined in the kernel by the * macro **MAX_TAIL_CALL_CNT** (not accessible to user space), * which is currently set to 32. * Return * 0 on success, or a negative error in case of failure. * * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags) * Description * Clone and redirect the packet associated to *skb* to another * net device of index *ifindex*. Both ingress and egress * interfaces can be used for redirection. The **BPF_F_INGRESS** * value in *flags* is used to make the distinction (ingress path * is selected if the flag is present, egress path otherwise). * This is the only flag supported for now. * * In comparison with **bpf_redirect**\ () helper, * **bpf_clone_redirect**\ () has the associated cost of * duplicating the packet buffer, but this can be executed out of * the eBPF program. Conversely, **bpf_redirect**\ () is more * efficient, but it is handled through an action code where the * redirection happens only after the eBPF program has returned. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. Positive * error indicates a potential drop or congestion in the target * device. The particular positive error codes are not defined. * * u64 bpf_get_current_pid_tgid(void) * Return * A 64-bit integer containing the current tgid and pid, and * created as such: * *current_task*\ **->tgid << 32 \|** * *current_task*\ **->pid**. * * u64 bpf_get_current_uid_gid(void) * Return * A 64-bit integer containing the current GID and UID, and * created as such: *current_gid* **<< 32 \|** *current_uid*. * * long bpf_get_current_comm(void *buf, u32 size_of_buf) * Description * Copy the **comm** attribute of the current task into *buf* of * *size_of_buf*. The **comm** attribute contains the name of * the executable (excluding the path) for the current task. The * *size_of_buf* must be strictly positive. On success, the * helper makes sure that the *buf* is NUL-terminated. On failure, * it is filled with zeroes. * Return * 0 on success, or a negative error in case of failure. * * u32 bpf_get_cgroup_classid(struct sk_buff *skb) * Description * Retrieve the classid for the current task, i.e. for the net_cls * cgroup to which *skb* belongs. * * This helper can be used on TC egress path, but not on ingress. * * The net_cls cgroup provides an interface to tag network packets * based on a user-provided identifier for all traffic coming from * the tasks belonging to the related cgroup. See also the related * kernel documentation, available from the Linux sources in file * *Documentation/admin-guide/cgroup-v1/net_cls.rst*. * * The Linux kernel has two versions for cgroups: there are * cgroups v1 and cgroups v2. Both are available to users, who can * use a mixture of them, but note that the net_cls cgroup is for * cgroup v1 only. This makes it incompatible with BPF programs * run on cgroups, which is a cgroup-v2-only feature (a socket can * only hold data for one version of cgroups at a time). * * This helper is only available is the kernel was compiled with * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to * "**y**" or to "**m**". * Return * The classid, or 0 for the default unconfigured classid. * * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci) * Description * Push a *vlan_tci* (VLAN tag control information) of protocol * *vlan_proto* to the packet associated to *skb*, then update * the checksum. Note that if *vlan_proto* is different from * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to * be **ETH_P_8021Q**. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_vlan_pop(struct sk_buff *skb) * Description * Pop a VLAN header from the packet associated to *skb*. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags) * Description * Get tunnel metadata. This helper takes a pointer *key* to an * empty **struct bpf_tunnel_key** of **size**, that will be * filled with tunnel metadata for the packet associated to *skb*. * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which * indicates that the tunnel is based on IPv6 protocol instead of * IPv4. * * The **struct bpf_tunnel_key** is an object that generalizes the * principal parameters used by various tunneling protocols into a * single struct. This way, it can be used to easily make a * decision based on the contents of the encapsulation header, * "summarized" in this struct. In particular, it holds the IP * address of the remote end (IPv4 or IPv6, depending on the case) * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also, * this struct exposes the *key*\ **->tunnel_id**, which is * generally mapped to a VNI (Virtual Network Identifier), making * it programmable together with the **bpf_skb_set_tunnel_key**\ * () helper. * * Let's imagine that the following code is part of a program * attached to the TC ingress interface, on one end of a GRE * tunnel, and is supposed to filter out all messages coming from * remote ends with IPv4 address other than 10.0.0.1: * * :: * * int ret; * struct bpf_tunnel_key key = {}; * * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0); * if (ret < 0) * return TC_ACT_SHOT; // drop packet * * if (key.remote_ipv4 != 0x0a000001) * return TC_ACT_SHOT; // drop packet * * return TC_ACT_OK; // accept packet * * This interface can also be used with all encapsulation devices * that can operate in "collect metadata" mode: instead of having * one network device per specific configuration, the "collect * metadata" mode only requires a single device where the * configuration can be extracted from this helper. * * This can be used together with various tunnels such as VXLan, * Geneve, GRE or IP in IP (IPIP). * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags) * Description * Populate tunnel metadata for packet associated to *skb.* The * tunnel metadata is set to the contents of *key*, of *size*. The * *flags* can be set to a combination of the following values: * * **BPF_F_TUNINFO_IPV6** * Indicate that the tunnel is based on IPv6 protocol * instead of IPv4. * **BPF_F_ZERO_CSUM_TX** * For IPv4 packets, add a flag to tunnel metadata * indicating that checksum computation should be skipped * and checksum set to zeroes. * **BPF_F_DONT_FRAGMENT** * Add a flag to tunnel metadata indicating that the * packet should not be fragmented. * **BPF_F_SEQ_NUMBER** * Add a flag to tunnel metadata indicating that a * sequence number should be added to tunnel header before * sending the packet. This flag was added for GRE * encapsulation, but might be used with other protocols * as well in the future. * * Here is a typical usage on the transmit path: * * :: * * struct bpf_tunnel_key key; * populate key ... * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0); * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0); * * See also the description of the **bpf_skb_get_tunnel_key**\ () * helper for additional information. * Return * 0 on success, or a negative error in case of failure. * * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags) * Description * Read the value of a perf event counter. This helper relies on a * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of * the perf event counter is selected when *map* is updated with * perf event file descriptors. The *map* is an array whose size * is the number of available CPUs, and each cell contains a value * relative to one CPU. The value to retrieve is indicated by * *flags*, that contains the index of the CPU to look up, masked * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to * **BPF_F_CURRENT_CPU** to indicate that the value for the * current CPU should be retrieved. * * Note that before Linux 4.13, only hardware perf event can be * retrieved. * * Also, be aware that the newer helper * **bpf_perf_event_read_value**\ () is recommended over * **bpf_perf_event_read**\ () in general. The latter has some ABI * quirks where error and counter value are used as a return code * (which is wrong to do since ranges may overlap). This issue is * fixed with **bpf_perf_event_read_value**\ (), which at the same * time provides more features over the **bpf_perf_event_read**\ * () interface. Please refer to the description of * **bpf_perf_event_read_value**\ () for details. * Return * The value of the perf event counter read from the map, or a * negative error code in case of failure. * * long bpf_redirect(u32 ifindex, u64 flags) * Description * Redirect the packet to another net device of index *ifindex*. * This helper is somewhat similar to **bpf_clone_redirect**\ * (), except that the packet is not cloned, which provides * increased performance. * * Except for XDP, both ingress and egress interfaces can be used * for redirection. The **BPF_F_INGRESS** value in *flags* is used * to make the distinction (ingress path is selected if the flag * is present, egress path otherwise). Currently, XDP only * supports redirection to the egress interface, and accepts no * flag at all. * * The same effect can also be attained with the more generic * **bpf_redirect_map**\ (), which uses a BPF map to store the * redirect target instead of providing it directly to the helper. * Return * For XDP, the helper returns **XDP_REDIRECT** on success or * **XDP_ABORTED** on error. For other program types, the values * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on * error. * * u32 bpf_get_route_realm(struct sk_buff *skb) * Description * Retrieve the realm or the route, that is to say the * **tclassid** field of the destination for the *skb*. The * identifier retrieved is a user-provided tag, similar to the * one used with the net_cls cgroup (see description for * **bpf_get_cgroup_classid**\ () helper), but here this tag is * held by a route (a destination entry), not by a task. * * Retrieving this identifier works with the clsact TC egress hook * (see also **tc-bpf(8)**), or alternatively on conventional * classful egress qdiscs, but not on TC ingress path. In case of * clsact TC egress hook, this has the advantage that, internally, * the destination entry has not been dropped yet in the transmit * path. Therefore, the destination entry does not need to be * artificially held via **netif_keep_dst**\ () for a classful * qdisc until the *skb* is freed. * * This helper is available only if the kernel was compiled with * **CONFIG_IP_ROUTE_CLASSID** configuration option. * Return * The realm of the route for the packet associated to *skb*, or 0 * if none was found. * * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size) * Description * Write raw *data* blob into a special BPF perf event held by * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf * event must have the following attributes: **PERF_SAMPLE_RAW** * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and * **PERF_COUNT_SW_BPF_OUTPUT** as **config**. * * The *flags* are used to indicate the index in *map* for which * the value must be put, masked with **BPF_F_INDEX_MASK**. * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU** * to indicate that the index of the current CPU core should be * used. * * The value to write, of *size*, is passed through eBPF stack and * pointed by *data*. * * The context of the program *ctx* needs also be passed to the * helper. * * On user space, a program willing to read the values needs to * call **perf_event_open**\ () on the perf event (either for * one or for all CPUs) and to store the file descriptor into the * *map*. This must be done before the eBPF program can send data * into it. An example is available in file * *samples/bpf/trace_output_user.c* in the Linux kernel source * tree (the eBPF program counterpart is in * *samples/bpf/trace_output_kern.c*). * * **bpf_perf_event_output**\ () achieves better performance * than **bpf_trace_printk**\ () for sharing data with user * space, and is much better suitable for streaming data from eBPF * programs. * * Note that this helper is not restricted to tracing use cases * and can be used with programs attached to TC or XDP as well, * where it allows for passing data to user space listeners. Data * can be: * * * Only custom structs, * * Only the packet payload, or * * A combination of both. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len) * Description * This helper was provided as an easy way to load data from a * packet. It can be used to load *len* bytes from *offset* from * the packet associated to *skb*, into the buffer pointed by * *to*. * * Since Linux 4.7, usage of this helper has mostly been replaced * by "direct packet access", enabling packet data to be * manipulated with *skb*\ **->data** and *skb*\ **->data_end** * pointing respectively to the first byte of packet data and to * the byte after the last byte of packet data. However, it * remains useful if one wishes to read large quantities of data * at once from a packet into the eBPF stack. * Return * 0 on success, or a negative error in case of failure. * * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags) * Description * Walk a user or a kernel stack and return its id. To achieve * this, the helper needs *ctx*, which is a pointer to the context * on which the tracing program is executed, and a pointer to a * *map* of type **BPF_MAP_TYPE_STACK_TRACE**. * * The last argument, *flags*, holds the number of stack frames to * skip (from 0 to 255), masked with * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set * a combination of the following flags: * * **BPF_F_USER_STACK** * Collect a user space stack instead of a kernel stack. * **BPF_F_FAST_STACK_CMP** * Compare stacks by hash only. * **BPF_F_REUSE_STACKID** * If two different stacks hash into the same *stackid*, * discard the old one. * * The stack id retrieved is a 32 bit long integer handle which * can be further combined with other data (including other stack * ids) and used as a key into maps. This can be useful for * generating a variety of graphs (such as flame graphs or off-cpu * graphs). * * For walking a stack, this helper is an improvement over * **bpf_probe_read**\ (), which can be used with unrolled loops * but is not efficient and consumes a lot of eBPF instructions. * Instead, **bpf_get_stackid**\ () can collect up to * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that * this limit can be controlled with the **sysctl** program, and * that it should be manually increased in order to profile long * user stacks (such as stacks for Java programs). To do so, use: * * :: * * # sysctl kernel.perf_event_max_stack=<new value> * Return * The positive or null stack id on success, or a negative error * in case of failure. * * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed) * Description * Compute a checksum difference, from the raw buffer pointed by * *from*, of length *from_size* (that must be a multiple of 4), * towards the raw buffer pointed by *to*, of size *to_size* * (same remark). An optional *seed* can be added to the value * (this can be cascaded, the seed may come from a previous call * to the helper). * * This is flexible enough to be used in several ways: * * * With *from_size* == 0, *to_size* > 0 and *seed* set to * checksum, it can be used when pushing new data. * * With *from_size* > 0, *to_size* == 0 and *seed* set to * checksum, it can be used when removing data from a packet. * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it * can be used to compute a diff. Note that *from_size* and * *to_size* do not need to be equal. * * This helper can be used in combination with * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to * which one can feed in the difference computed with * **bpf_csum_diff**\ (). * Return * The checksum result, or a negative error code in case of * failure. * * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size) * Description * Retrieve tunnel options metadata for the packet associated to * *skb*, and store the raw tunnel option data to the buffer *opt* * of *size*. * * This helper can be used with encapsulation devices that can * operate in "collect metadata" mode (please refer to the related * note in the description of **bpf_skb_get_tunnel_key**\ () for * more details). A particular example where this can be used is * in combination with the Geneve encapsulation protocol, where it * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper) * and retrieving arbitrary TLVs (Type-Length-Value headers) from * the eBPF program. This allows for full customization of these * headers. * Return * The size of the option data retrieved. * * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size) * Description * Set tunnel options metadata for the packet associated to *skb* * to the option data contained in the raw buffer *opt* of *size*. * * See also the description of the **bpf_skb_get_tunnel_opt**\ () * helper for additional information. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags) * Description * Change the protocol of the *skb* to *proto*. Currently * supported are transition from IPv4 to IPv6, and from IPv6 to * IPv4. The helper takes care of the groundwork for the * transition, including resizing the socket buffer. The eBPF * program is expected to fill the new headers, if any, via * **skb_store_bytes**\ () and to recompute the checksums with * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ * (). The main case for this helper is to perform NAT64 * operations out of an eBPF program. * * Internally, the GSO type is marked as dodgy so that headers are * checked and segments are recalculated by the GSO/GRO engine. * The size for GSO target is adapted as well. * * All values for *flags* are reserved for future usage, and must * be left at zero. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_change_type(struct sk_buff *skb, u32 type) * Description * Change the packet type for the packet associated to *skb*. This * comes down to setting *skb*\ **->pkt_type** to *type*, except * the eBPF program does not have a write access to *skb*\ * **->pkt_type** beside this helper. Using a helper here allows * for graceful handling of errors. * * The major use case is to change incoming *skb*s to * **PACKET_HOST** in a programmatic way instead of having to * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for * example. * * Note that *type* only allows certain values. At this time, they * are: * * **PACKET_HOST** * Packet is for us. * **PACKET_BROADCAST** * Send packet to all. * **PACKET_MULTICAST** * Send packet to group. * **PACKET_OTHERHOST** * Send packet to someone else. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index) * Description * Check whether *skb* is a descendant of the cgroup2 held by * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*. * Return * The return value depends on the result of the test, and can be: * * * 0, if the *skb* failed the cgroup2 descendant test. * * 1, if the *skb* succeeded the cgroup2 descendant test. * * A negative error code, if an error occurred. * * u32 bpf_get_hash_recalc(struct sk_buff *skb) * Description * Retrieve the hash of the packet, *skb*\ **->hash**. If it is * not set, in particular if the hash was cleared due to mangling, * recompute this hash. Later accesses to the hash can be done * directly with *skb*\ **->hash**. * * Calling **bpf_set_hash_invalid**\ (), changing a packet * prototype with **bpf_skb_change_proto**\ (), or calling * **bpf_skb_store_bytes**\ () with the * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear * the hash and to trigger a new computation for the next call to * **bpf_get_hash_recalc**\ (). * Return * The 32-bit hash. * * u64 bpf_get_current_task(void) * Return * A pointer to the current task struct. * * long bpf_probe_write_user(void *dst, const void *src, u32 len) * Description * Attempt in a safe way to write *len* bytes from the buffer * *src* to *dst* in memory. It only works for threads that are in * user context, and *dst* must be a valid user space address. * * This helper should not be used to implement any kind of * security mechanism because of TOC-TOU attacks, but rather to * debug, divert, and manipulate execution of semi-cooperative * processes. * * Keep in mind that this feature is meant for experiments, and it * has a risk of crashing the system and running programs. * Therefore, when an eBPF program using this helper is attached, * a warning including PID and process name is printed to kernel * logs. * Return * 0 on success, or a negative error in case of failure. * * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index) * Description * Check whether the probe is being run is the context of a given * subset of the cgroup2 hierarchy. The cgroup2 to test is held by * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*. * Return * The return value depends on the result of the test, and can be: * * * 1, if current task belongs to the cgroup2. * * 0, if current task does not belong to the cgroup2. * * A negative error code, if an error occurred. * * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags) * Description * Resize (trim or grow) the packet associated to *skb* to the * new *len*. The *flags* are reserved for future usage, and must * be left at zero. * * The basic idea is that the helper performs the needed work to * change the size of the packet, then the eBPF program rewrites * the rest via helpers like **bpf_skb_store_bytes**\ (), * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ () * and others. This helper is a slow path utility intended for * replies with control messages. And because it is targeted for * slow path, the helper itself can afford to be slow: it * implicitly linearizes, unclones and drops offloads from the * *skb*. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_pull_data(struct sk_buff *skb, u32 len) * Description * Pull in non-linear data in case the *skb* is non-linear and not * all of *len* are part of the linear section. Make *len* bytes * from *skb* readable and writable. If a zero value is passed for * *len*, then the whole length of the *skb* is pulled. * * This helper is only needed for reading and writing with direct * packet access. * * For direct packet access, testing that offsets to access * are within packet boundaries (test on *skb*\ **->data_end**) is * susceptible to fail if offsets are invalid, or if the requested * data is in non-linear parts of the *skb*. On failure the * program can just bail out, or in the case of a non-linear * buffer, use a helper to make the data available. The * **bpf_skb_load_bytes**\ () helper is a first solution to access * the data. Another one consists in using **bpf_skb_pull_data** * to pull in once the non-linear parts, then retesting and * eventually access the data. * * At the same time, this also makes sure the *skb* is uncloned, * which is a necessary condition for direct write. As this needs * to be an invariant for the write part only, the verifier * detects writes and adds a prologue that is calling * **bpf_skb_pull_data()** to effectively unclone the *skb* from * the very beginning in case it is indeed cloned. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum) * Description * Add the checksum *csum* into *skb*\ **->csum** in case the * driver has supplied a checksum for the entire packet into that * field. Return an error otherwise. This helper is intended to be * used in combination with **bpf_csum_diff**\ (), in particular * when the checksum needs to be updated after data has been * written into the packet through direct packet access. * Return * The checksum on success, or a negative error code in case of * failure. * * void bpf_set_hash_invalid(struct sk_buff *skb) * Description * Invalidate the current *skb*\ **->hash**. It can be used after * mangling on headers through direct packet access, in order to * indicate that the hash is outdated and to trigger a * recalculation the next time the kernel tries to access this * hash or when the **bpf_get_hash_recalc**\ () helper is called. * * long bpf_get_numa_node_id(void) * Description * Return the id of the current NUMA node. The primary use case * for this helper is the selection of sockets for the local NUMA * node, when the program is attached to sockets using the * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**), * but the helper is also available to other eBPF program types, * similarly to **bpf_get_smp_processor_id**\ (). * Return * The id of current NUMA node. * * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags) * Description * Grows headroom of packet associated to *skb* and adjusts the * offset of the MAC header accordingly, adding *len* bytes of * space. It automatically extends and reallocates memory as * required. * * This helper can be used on a layer 3 *skb* to push a MAC header * for redirection into a layer 2 device. * * All values for *flags* are reserved for future usage, and must * be left at zero. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta) * Description * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that * it is possible to use a negative value for *delta*. This helper * can be used to prepare the packet for pushing or popping * headers. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr) * Description * Copy a NUL terminated string from an unsafe kernel address * *unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for * more details. * * Generally, use **bpf_probe_read_user_str**\ () or * **bpf_probe_read_kernel_str**\ () instead. * Return * On success, the strictly positive length of the string, * including the trailing NUL character. On error, a negative * value. * * u64 bpf_get_socket_cookie(struct sk_buff *skb) * Description * If the **struct sk_buff** pointed by *skb* has a known socket, * retrieve the cookie (generated by the kernel) of this socket. * If no cookie has been set yet, generate a new cookie. Once * generated, the socket cookie remains stable for the life of the * socket. This helper can be useful for monitoring per socket * networking traffic statistics as it provides a global socket * identifier that can be assumed unique. * Return * A 8-byte long non-decreasing number on success, or 0 if the * socket field is missing inside *skb*. * * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx) * Description * Equivalent to bpf_get_socket_cookie() helper that accepts * *skb*, but gets socket from **struct bpf_sock_addr** context. * Return * A 8-byte long non-decreasing number. * * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx) * Description * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts * *skb*, but gets socket from **struct bpf_sock_ops** context. * Return * A 8-byte long non-decreasing number. * * u32 bpf_get_socket_uid(struct sk_buff *skb) * Return * The owner UID of the socket associated to *skb*. If the socket * is **NULL**, or if it is not a full socket (i.e. if it is a * time-wait or a request socket instead), **overflowuid** value * is returned (note that **overflowuid** might also be the actual * UID value for the socket). * * long bpf_set_hash(struct sk_buff *skb, u32 hash) * Description * Set the full hash for *skb* (set the field *skb*\ **->hash**) * to value *hash*. * Return * 0 * * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen) * Description * Emulate a call to **setsockopt()** on the socket associated to * *bpf_socket*, which must be a full socket. The *level* at * which the option resides and the name *optname* of the option * must be specified, see **setsockopt(2)** for more information. * The option value of length *optlen* is pointed by *optval*. * * *bpf_socket* should be one of the following: * * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**. * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT** * and **BPF_CGROUP_INET6_CONNECT**. * * This helper actually implements a subset of **setsockopt()**. * It supports the following *level*\ s: * * * **SOL_SOCKET**, which supports the following *optname*\ s: * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**, * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**, * **SO_BINDTODEVICE**, **SO_KEEPALIVE**. * * **IPPROTO_TCP**, which supports the following *optname*\ s: * **TCP_CONGESTION**, **TCP_BPF_IW**, * **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**, * **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**, * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags) * Description * Grow or shrink the room for data in the packet associated to * *skb* by *len_diff*, and according to the selected *mode*. * * By default, the helper will reset any offloaded checksum * indicator of the skb to CHECKSUM_NONE. This can be avoided * by the following flag: * * * **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded * checksum data of the skb to CHECKSUM_NONE. * * There are two supported modes at this time: * * * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer * (room space is added or removed below the layer 2 header). * * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer * (room space is added or removed below the layer 3 header). * * The following flags are supported at this time: * * * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size. * Adjusting mss in this way is not allowed for datagrams. * * * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**, * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**: * Any new space is reserved to hold a tunnel header. * Configure skb offsets and other fields accordingly. * * * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**, * **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**: * Use with ENCAP_L3 flags to further specify the tunnel type. * * * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*): * Use with ENCAP_L3/L4 flags to further specify the tunnel * type; *len* is the length of the inner MAC header. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) * Description * Redirect the packet to the endpoint referenced by *map* at * index *key*. Depending on its type, this *map* can contain * references to net devices (for forwarding packets through other * ports), or to CPUs (for redirecting XDP frames to another CPU; * but this is only implemented for native XDP (with driver * support) as of this writing). * * The lower two bits of *flags* are used as the return code if * the map lookup fails. This is so that the return value can be * one of the XDP program return codes up to **XDP_TX**, as chosen * by the caller. Any higher bits in the *flags* argument must be * unset. * * See also **bpf_redirect**\ (), which only supports redirecting * to an ifindex, but doesn't require a map to do so. * Return * **XDP_REDIRECT** on success, or the value of the two lower bits * of the *flags* argument on error. * * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags) * Description * Redirect the packet to the socket referenced by *map* (of type * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and * egress interfaces can be used for redirection. The * **BPF_F_INGRESS** value in *flags* is used to make the * distinction (ingress path is selected if the flag is present, * egress path otherwise). This is the only flag supported for now. * Return * **SK_PASS** on success, or **SK_DROP** on error. * * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags) * Description * Add an entry to, or update a *map* referencing sockets. The * *skops* is used as a new value for the entry associated to * *key*. *flags* is one of: * * **BPF_NOEXIST** * The entry for *key* must not exist in the map. * **BPF_EXIST** * The entry for *key* must already exist in the map. * **BPF_ANY** * No condition on the existence of the entry for *key*. * * If the *map* has eBPF programs (parser and verdict), those will * be inherited by the socket being added. If the socket is * already attached to eBPF programs, this results in an error. * Return * 0 on success, or a negative error in case of failure. * * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta) * Description * Adjust the address pointed by *xdp_md*\ **->data_meta** by * *delta* (which can be positive or negative). Note that this * operation modifies the address stored in *xdp_md*\ **->data**, * so the latter must be loaded only after the helper has been * called. * * The use of *xdp_md*\ **->data_meta** is optional and programs * are not required to use it. The rationale is that when the * packet is processed with XDP (e.g. as DoS filter), it is * possible to push further meta data along with it before passing * to the stack, and to give the guarantee that an ingress eBPF * program attached as a TC classifier on the same device can pick * this up for further post-processing. Since TC works with socket * buffers, it remains possible to set from XDP the **mark** or * **priority** pointers, or other pointers for the socket buffer. * Having this scratch space generic and programmable allows for * more flexibility as the user is free to store whatever meta * data they need. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size) * Description * Read the value of a perf event counter, and store it into *buf* * of size *buf_size*. This helper relies on a *map* of type * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event * counter is selected when *map* is updated with perf event file * descriptors. The *map* is an array whose size is the number of * available CPUs, and each cell contains a value relative to one * CPU. The value to retrieve is indicated by *flags*, that * contains the index of the CPU to look up, masked with * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to * **BPF_F_CURRENT_CPU** to indicate that the value for the * current CPU should be retrieved. * * This helper behaves in a way close to * **bpf_perf_event_read**\ () helper, save that instead of * just returning the value observed, it fills the *buf* * structure. This allows for additional data to be retrieved: in * particular, the enabled and running times (in *buf*\ * **->enabled** and *buf*\ **->running**, respectively) are * copied. In general, **bpf_perf_event_read_value**\ () is * recommended over **bpf_perf_event_read**\ (), which has some * ABI issues and provides fewer functionalities. * * These values are interesting, because hardware PMU (Performance * Monitoring Unit) counters are limited resources. When there are * more PMU based perf events opened than available counters, * kernel will multiplex these events so each event gets certain * percentage (but not all) of the PMU time. In case that * multiplexing happens, the number of samples or counter value * will not reflect the case compared to when no multiplexing * occurs. This makes comparison between different runs difficult. * Typically, the counter value should be normalized before * comparing to other experiments. The usual normalization is done * as follows. * * :: * * normalized_counter = counter * t_enabled / t_running * * Where t_enabled is the time enabled for event and t_running is * the time running for event since last normalization. The * enabled and running times are accumulated since the perf event * open. To achieve scaling factor between two invocations of an * eBPF program, users can use CPU id as the key (which is * typical for perf array usage model) to remember the previous * value and do the calculation inside the eBPF program. * Return * 0 on success, or a negative error in case of failure. * * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size) * Description * For en eBPF program attached to a perf event, retrieve the * value of the event counter associated to *ctx* and store it in * the structure pointed by *buf* and of size *buf_size*. Enabled * and running times are also stored in the structure (see * description of helper **bpf_perf_event_read_value**\ () for * more details). * Return * 0 on success, or a negative error in case of failure. * * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen) * Description * Emulate a call to **getsockopt()** on the socket associated to * *bpf_socket*, which must be a full socket. The *level* at * which the option resides and the name *optname* of the option * must be specified, see **getsockopt(2)** for more information. * The retrieved value is stored in the structure pointed by * *opval* and of length *optlen*. * * *bpf_socket* should be one of the following: * * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**. * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT** * and **BPF_CGROUP_INET6_CONNECT**. * * This helper actually implements a subset of **getsockopt()**. * It supports the following *level*\ s: * * * **IPPROTO_TCP**, which supports *optname* * **TCP_CONGESTION**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. * Return * 0 on success, or a negative error in case of failure. * * long bpf_override_return(struct pt_regs *regs, u64 rc) * Description * Used for error injection, this helper uses kprobes to override * the return value of the probed function, and to set it to *rc*. * The first argument is the context *regs* on which the kprobe * works. * * This helper works by setting the PC (program counter) * to an override function which is run in place of the original * probed function. This means the probed function is not run at * all. The replacement function just returns with the required * value. * * This helper has security implications, and thus is subject to * restrictions. It is only available if the kernel was compiled * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration * option, and in this case it only works on functions tagged with * **ALLOW_ERROR_INJECTION** in the kernel code. * * Also, the helper is only available for the architectures having * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing, * x86 architecture is the only one to support this feature. * Return * 0 * * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval) * Description * Attempt to set the value of the **bpf_sock_ops_cb_flags** field * for the full TCP socket associated to *bpf_sock_ops* to * *argval*. * * The primary use of this field is to determine if there should * be calls to eBPF programs of type * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP * code. A program of the same type can change its value, per * connection and as necessary, when the connection is * established. This field is directly accessible for reading, but * this helper must be used for updates in order to return an * error if an eBPF program tries to set a callback that is not * supported in the current kernel. * * *argval* is a flag array which can combine these flags: * * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out) * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission) * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change) * * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT) * * Therefore, this function can be used to clear a callback flag by * setting the appropriate bit to zero. e.g. to disable the RTO * callback: * * **bpf_sock_ops_cb_flags_set(bpf_sock,** * **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)** * * Here are some examples of where one could call such eBPF * program: * * * When RTO fires. * * When a packet is retransmitted. * * When the connection terminates. * * When a packet is sent. * * When a packet is received. * Return * Code **-EINVAL** if the socket is not a full TCP socket; * otherwise, a positive number containing the bits that could not * be set is returned (which comes down to 0 if all bits were set * as required). * * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags) * Description * This helper is used in programs implementing policies at the * socket level. If the message *msg* is allowed to pass (i.e. if * the verdict eBPF program returns **SK_PASS**), redirect it to * the socket referenced by *map* (of type * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and * egress interfaces can be used for redirection. The * **BPF_F_INGRESS** value in *flags* is used to make the * distinction (ingress path is selected if the flag is present, * egress path otherwise). This is the only flag supported for now. * Return * **SK_PASS** on success, or **SK_DROP** on error. * * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes) * Description * For socket policies, apply the verdict of the eBPF program to * the next *bytes* (number of bytes) of message *msg*. * * For example, this helper can be used in the following cases: * * * A single **sendmsg**\ () or **sendfile**\ () system call * contains multiple logical messages that the eBPF program is * supposed to read and for which it should apply a verdict. * * An eBPF program only cares to read the first *bytes* of a * *msg*. If the message has a large payload, then setting up * and calling the eBPF program repeatedly for all bytes, even * though the verdict is already known, would create unnecessary * overhead. * * When called from within an eBPF program, the helper sets a * counter internal to the BPF infrastructure, that is used to * apply the last verdict to the next *bytes*. If *bytes* is * smaller than the current data being processed from a * **sendmsg**\ () or **sendfile**\ () system call, the first * *bytes* will be sent and the eBPF program will be re-run with * the pointer for start of data pointing to byte number *bytes* * **+ 1**. If *bytes* is larger than the current data being * processed, then the eBPF verdict will be applied to multiple * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are * consumed. * * Note that if a socket closes with the internal counter holding * a non-zero value, this is not a problem because data is not * being buffered for *bytes* and is sent as it is received. * Return * 0 * * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes) * Description * For socket policies, prevent the execution of the verdict eBPF * program for message *msg* until *bytes* (byte number) have been * accumulated. * * This can be used when one needs a specific number of bytes * before a verdict can be assigned, even if the data spans * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme * case would be a user calling **sendmsg**\ () repeatedly with * 1-byte long message segments. Obviously, this is bad for * performance, but it is still valid. If the eBPF program needs * *bytes* bytes to validate a header, this helper can be used to * prevent the eBPF program to be called again until *bytes* have * been accumulated. * Return * 0 * * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags) * Description * For socket policies, pull in non-linear data from user space * for *msg* and set pointers *msg*\ **->data** and *msg*\ * **->data_end** to *start* and *end* bytes offsets into *msg*, * respectively. * * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a * *msg* it can only parse data that the (**data**, **data_end**) * pointers have already consumed. For **sendmsg**\ () hooks this * is likely the first scatterlist element. But for calls relying * on the **sendpage** handler (e.g. **sendfile**\ ()) this will * be the range (**0**, **0**) because the data is shared with * user space and by default the objective is to avoid allowing * user space to modify data while (or after) eBPF verdict is * being decided. This helper can be used to pull in data and to * set the start and end pointer to given values. Data will be * copied if necessary (i.e. if data was not linear and if start * and end pointers do not point to the same chunk). * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * * All values for *flags* are reserved for future usage, and must * be left at zero. * Return * 0 on success, or a negative error in case of failure. * * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len) * Description * Bind the socket associated to *ctx* to the address pointed by * *addr*, of length *addr_len*. This allows for making outgoing * connection from the desired IP address, which can be useful for * example when all processes inside a cgroup should use one * single IP address on a host that has multiple IP configured. * * This helper works for IPv4 and IPv6, TCP and UDP sockets. The * domain (*addr*\ **->sa_family**) must be **AF_INET** (or * **AF_INET6**). It's advised to pass zero port (**sin_port** * or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like * behavior and lets the kernel efficiently pick up an unused * port as long as 4-tuple is unique. Passing non-zero port might * lead to degraded performance. * Return * 0 on success, or a negative error in case of failure. * * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta) * Description * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is * possible to both shrink and grow the packet tail. * Shrink done via *delta* being a negative integer. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags) * Description * Retrieve the XFRM state (IP transform framework, see also * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*. * * The retrieved value is stored in the **struct bpf_xfrm_state** * pointed by *xfrm_state* and of length *size*. * * All values for *flags* are reserved for future usage, and must * be left at zero. * * This helper is available only if the kernel was compiled with * **CONFIG_XFRM** configuration option. * Return * 0 on success, or a negative error in case of failure. * * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags) * Description * Return a user or a kernel stack in bpf program provided buffer. * To achieve this, the helper needs *ctx*, which is a pointer * to the context on which the tracing program is executed. * To store the stacktrace, the bpf program provides *buf* with * a nonnegative *size*. * * The last argument, *flags*, holds the number of stack frames to * skip (from 0 to 255), masked with * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set * the following flags: * * **BPF_F_USER_STACK** * Collect a user space stack instead of a kernel stack. * **BPF_F_USER_BUILD_ID** * Collect buildid+offset instead of ips for user stack, * only valid if **BPF_F_USER_STACK** is also specified. * * **bpf_get_stack**\ () can collect up to * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject * to sufficient large buffer size. Note that * this limit can be controlled with the **sysctl** program, and * that it should be manually increased in order to profile long * user stacks (such as stacks for Java programs). To do so, use: * * :: * * # sysctl kernel.perf_event_max_stack=<new value> * Return * The non-negative copied *buf* length equal to or less than * *size* on success, or a negative error in case of failure. * * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header) * Description * This helper is similar to **bpf_skb_load_bytes**\ () in that * it provides an easy way to load *len* bytes from *offset* * from the packet associated to *skb*, into the buffer pointed * by *to*. The difference to **bpf_skb_load_bytes**\ () is that * a fifth argument *start_header* exists in order to select a * base offset to start from. *start_header* can be one of: * * **BPF_HDR_START_MAC** * Base offset to load data from is *skb*'s mac header. * **BPF_HDR_START_NET** * Base offset to load data from is *skb*'s network header. * * In general, "direct packet access" is the preferred method to * access packet data, however, this helper is in particular useful * in socket filters where *skb*\ **->data** does not always point * to the start of the mac header and where "direct packet access" * is not available. * Return * 0 on success, or a negative error in case of failure. * * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags) * Description * Do FIB lookup in kernel tables using parameters in *params*. * If lookup is successful and result shows packet is to be * forwarded, the neighbor tables are searched for the nexthop. * If successful (ie., FIB lookup shows forwarding and nexthop * is resolved), the nexthop address is returned in ipv4_dst * or ipv6_dst based on family, smac is set to mac address of * egress device, dmac is set to nexthop mac address, rt_metric * is set to metric from route (IPv4/IPv6 only), and ifindex * is set to the device index of the nexthop from the FIB lookup. * * *plen* argument is the size of the passed in struct. * *flags* argument can be a combination of one or more of the * following values: * * **BPF_FIB_LOOKUP_DIRECT** * Do a direct table lookup vs full lookup using FIB * rules. * **BPF_FIB_LOOKUP_OUTPUT** * Perform lookup from an egress perspective (default is * ingress). * * *ctx* is either **struct xdp_md** for XDP programs or * **struct sk_buff** tc cls_act programs. * Return * * < 0 if any input argument is invalid * * 0 on success (packet is forwarded, nexthop neighbor exists) * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the * packet is not forwarded or needs assist from full stack * * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags) * Description * Add an entry to, or update a sockhash *map* referencing sockets. * The *skops* is used as a new value for the entry associated to * *key*. *flags* is one of: * * **BPF_NOEXIST** * The entry for *key* must not exist in the map. * **BPF_EXIST** * The entry for *key* must already exist in the map. * **BPF_ANY** * No condition on the existence of the entry for *key*. * * If the *map* has eBPF programs (parser and verdict), those will * be inherited by the socket being added. If the socket is * already attached to eBPF programs, this results in an error. * Return * 0 on success, or a negative error in case of failure. * * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags) * Description * This helper is used in programs implementing policies at the * socket level. If the message *msg* is allowed to pass (i.e. if * the verdict eBPF program returns **SK_PASS**), redirect it to * the socket referenced by *map* (of type * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and * egress interfaces can be used for redirection. The * **BPF_F_INGRESS** value in *flags* is used to make the * distinction (ingress path is selected if the flag is present, * egress path otherwise). This is the only flag supported for now. * Return * **SK_PASS** on success, or **SK_DROP** on error. * * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags) * Description * This helper is used in programs implementing policies at the * skb socket level. If the sk_buff *skb* is allowed to pass (i.e. * if the verdict eBPF program returns **SK_PASS**), redirect it * to the socket referenced by *map* (of type * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and * egress interfaces can be used for redirection. The * **BPF_F_INGRESS** value in *flags* is used to make the * distinction (ingress path is selected if the flag is present, * egress otherwise). This is the only flag supported for now. * Return * **SK_PASS** on success, or **SK_DROP** on error. * * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len) * Description * Encapsulate the packet associated to *skb* within a Layer 3 * protocol header. This header is provided in the buffer at * address *hdr*, with *len* its size in bytes. *type* indicates * the protocol of the header and can be one of: * * **BPF_LWT_ENCAP_SEG6** * IPv6 encapsulation with Segment Routing Header * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH, * the IPv6 header is computed by the kernel. * **BPF_LWT_ENCAP_SEG6_INLINE** * Only works if *skb* contains an IPv6 packet. Insert a * Segment Routing Header (**struct ipv6_sr_hdr**) inside * the IPv6 header. * **BPF_LWT_ENCAP_IP** * IP encapsulation (GRE/GUE/IPIP/etc). The outer header * must be IPv4 or IPv6, followed by zero or more * additional headers, up to **LWT_BPF_MAX_HEADROOM** * total bytes in all prepended headers. Please note that * if **skb_is_gso**\ (*skb*) is true, no more than two * headers can be prepended, and the inner header, if * present, should be either GRE or UDP/GUE. * * **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs * of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can * be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and * **BPF_PROG_TYPE_LWT_XMIT**. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len) * Description * Store *len* bytes from address *from* into the packet * associated to *skb*, at *offset*. Only the flags, tag and TLVs * inside the outermost IPv6 Segment Routing Header can be * modified through this helper. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta) * Description * Adjust the size allocated to TLVs in the outermost IPv6 * Segment Routing Header contained in the packet associated to * *skb*, at position *offset* by *delta* bytes. Only offsets * after the segments are accepted. *delta* can be as well * positive (growing) as negative (shrinking). * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len) * Description * Apply an IPv6 Segment Routing action of type *action* to the * packet associated to *skb*. Each action takes a parameter * contained at address *param*, and of length *param_len* bytes. * *action* can be one of: * * **SEG6_LOCAL_ACTION_END_X** * End.X action: Endpoint with Layer-3 cross-connect. * Type of *param*: **struct in6_addr**. * **SEG6_LOCAL_ACTION_END_T** * End.T action: Endpoint with specific IPv6 table lookup. * Type of *param*: **int**. * **SEG6_LOCAL_ACTION_END_B6** * End.B6 action: Endpoint bound to an SRv6 policy. * Type of *param*: **struct ipv6_sr_hdr**. * **SEG6_LOCAL_ACTION_END_B6_ENCAP** * End.B6.Encap action: Endpoint bound to an SRv6 * encapsulation policy. * Type of *param*: **struct ipv6_sr_hdr**. * * A call to this helper is susceptible to change the underlying * packet buffer. Therefore, at load time, all checks on pointers * previously done by the verifier are invalidated and must be * performed again, if the helper is used in combination with * direct packet access. * Return * 0 on success, or a negative error in case of failure. * * long bpf_rc_repeat(void *ctx) * Description * This helper is used in programs implementing IR decoding, to * report a successfully decoded repeat key message. This delays * the generation of a key up event for previously generated * key down event. * * Some IR protocols like NEC have a special IR message for * repeating last button, for when a button is held down. * * The *ctx* should point to the lirc sample as passed into * the program. * * This helper is only available is the kernel was compiled with * the **CONFIG_BPF_LIRC_MODE2** configuration option set to * "**y**". * Return * 0 * * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle) * Description * This helper is used in programs implementing IR decoding, to * report a successfully decoded key press with *scancode*, * *toggle* value in the given *protocol*. The scancode will be * translated to a keycode using the rc keymap, and reported as * an input key down event. After a period a key up event is * generated. This period can be extended by calling either * **bpf_rc_keydown**\ () again with the same values, or calling * **bpf_rc_repeat**\ (). * * Some protocols include a toggle bit, in case the button was * released and pressed again between consecutive scancodes. * * The *ctx* should point to the lirc sample as passed into * the program. * * The *protocol* is the decoded protocol number (see * **enum rc_proto** for some predefined values). * * This helper is only available is the kernel was compiled with * the **CONFIG_BPF_LIRC_MODE2** configuration option set to * "**y**". * Return * 0 * * u64 bpf_skb_cgroup_id(struct sk_buff *skb) * Description * Return the cgroup v2 id of the socket associated with the *skb*. * This is roughly similar to the **bpf_get_cgroup_classid**\ () * helper for cgroup v1 by providing a tag resp. identifier that * can be matched on or used for map lookups e.g. to implement * policy. The cgroup v2 id of a given path in the hierarchy is * exposed in user space through the f_handle API in order to get * to the same 64-bit id. * * This helper can be used on TC egress path, but not on ingress, * and is available only if the kernel was compiled with the * **CONFIG_SOCK_CGROUP_DATA** configuration option. * Return * The id is returned or 0 in case the id could not be retrieved. * * u64 bpf_get_current_cgroup_id(void) * Return * A 64-bit integer containing the current cgroup id based * on the cgroup within which the current task is running. * * void *bpf_get_local_storage(void *map, u64 flags) * Description * Get the pointer to the local storage area. * The type and the size of the local storage is defined * by the *map* argument. * The *flags* meaning is specific for each map type, * and has to be 0 for cgroup local storage. * * Depending on the BPF program type, a local storage area * can be shared between multiple instances of the BPF program, * running simultaneously. * * A user should care about the synchronization by himself. * For example, by using the **BPF_STX_XADD** instruction to alter * the shared data. * Return * A pointer to the local storage area. * * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags) * Description * Select a **SO_REUSEPORT** socket from a * **BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*. * It checks the selected socket is matching the incoming * request in the socket buffer. * Return * 0 on success, or a negative error in case of failure. * * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level) * Description * Return id of cgroup v2 that is ancestor of cgroup associated * with the *skb* at the *ancestor_level*. The root cgroup is at * *ancestor_level* zero and each step down the hierarchy * increments the level. If *ancestor_level* == level of cgroup * associated with *skb*, then return value will be same as that * of **bpf_skb_cgroup_id**\ (). * * The helper is useful to implement policies based on cgroups * that are upper in hierarchy than immediate cgroup associated * with *skb*. * * The format of returned id and helper limitations are same as in * **bpf_skb_cgroup_id**\ (). * Return * The id is returned or 0 in case the id could not be retrieved. * * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags) * Description * Look for TCP socket matching *tuple*, optionally in a child * network namespace *netns*. The return value must be checked, * and if non-**NULL**, released via **bpf_sk_release**\ (). * * The *ctx* should point to the context of the program, such as * the skb or socket (depending on the hook in use). This is used * to determine the base network namespace for the lookup. * * *tuple_size* must be one of: * * **sizeof**\ (*tuple*\ **->ipv4**) * Look for an IPv4 socket. * **sizeof**\ (*tuple*\ **->ipv6**) * Look for an IPv6 socket. * * If the *netns* is a negative signed 32-bit integer, then the * socket lookup table in the netns associated with the *ctx* * will be used. For the TC hooks, this is the netns of the device * in the skb. For socket hooks, this is the netns of the socket. * If *netns* is any other signed 32-bit value greater than or * equal to zero then it specifies the ID of the netns relative to * the netns associated with the *ctx*. *netns* values beyond the * range of 32-bit integers are reserved for future use. * * All values for *flags* are reserved for future usage, and must * be left at zero. * * This helper is available only if the kernel was compiled with * **CONFIG_NET** configuration option. * Return * Pointer to **struct bpf_sock**, or **NULL** in case of failure. * For sockets with reuseport option, the **struct bpf_sock** * result is from *reuse*\ **->socks**\ [] using the hash of the * tuple. * * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags) * Description * Look for UDP socket matching *tuple*, optionally in a child * network namespace *netns*. The return value must be checked, * and if non-**NULL**, released via **bpf_sk_release**\ (). * * The *ctx* should point to the context of the program, such as * the skb or socket (depending on the hook in use). This is used * to determine the base network namespace for the lookup. * * *tuple_size* must be one of: * * **sizeof**\ (*tuple*\ **->ipv4**) * Look for an IPv4 socket. * **sizeof**\ (*tuple*\ **->ipv6**) * Look for an IPv6 socket. * * If the *netns* is a negative signed 32-bit integer, then the * socket lookup table in the netns associated with the *ctx* * will be used. For the TC hooks, this is the netns of the device * in the skb. For socket hooks, this is the netns of the socket. * If *netns* is any other signed 32-bit value greater than or * equal to zero then it specifies the ID of the netns relative to * the netns associated with the *ctx*. *netns* values beyond the * range of 32-bit integers are reserved for future use. * * All values for *flags* are reserved for future usage, and must * be left at zero. * * This helper is available only if the kernel was compiled with * **CONFIG_NET** configuration option. * Return * Pointer to **struct bpf_sock**, or **NULL** in case of failure. * For sockets with reuseport option, the **struct bpf_sock** * result is from *reuse*\ **->socks**\ [] using the hash of the * tuple. * * long bpf_sk_release(void *sock) * Description * Release the reference held by *sock*. *sock* must be a * non-**NULL** pointer that was returned from * **bpf_sk_lookup_xxx**\ (). * Return * 0 on success, or a negative error in case of failure. * * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) * Description * Push an element *value* in *map*. *flags* is one of: * * **BPF_EXIST** * If the queue/stack is full, the oldest element is * removed to make room for this. * Return * 0 on success, or a negative error in case of failure. * * long bpf_map_pop_elem(struct bpf_map *map, void *value) * Description * Pop an element from *map*. * Return * 0 on success, or a negative error in case of failure. * * long bpf_map_peek_elem(struct bpf_map *map, void *value) * Description * Get an element from *map* without removing it. * Return * 0 on success, or a negative error in case of failure. * * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags) * Description * For socket policies, insert *len* bytes into *msg* at offset * *start*. * * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a * *msg* it may want to insert metadata or options into the *msg*. * This can later be read and used by any of the lower layer BPF * hooks. * * This helper may fail if under memory pressure (a malloc * fails) in these cases BPF programs will get an appropriate * error and BPF programs will need to handle them. * Return * 0 on success, or a negative error in case of failure. * * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags) * Description * Will remove *len* bytes from a *msg* starting at byte *start*. * This may result in **ENOMEM** errors under certain situations if * an allocation and copy are required due to a full ring buffer. * However, the helper will try to avoid doing the allocation * if possible. Other errors can occur if input parameters are * invalid either due to *start* byte not being valid part of *msg* * payload and/or *pop* value being to large. * Return * 0 on success, or a negative error in case of failure. * * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y) * Description * This helper is used in programs implementing IR decoding, to * report a successfully decoded pointer movement. * * The *ctx* should point to the lirc sample as passed into * the program. * * This helper is only available is the kernel was compiled with * the **CONFIG_BPF_LIRC_MODE2** configuration option set to * "**y**". * Return * 0 * * long bpf_spin_lock(struct bpf_spin_lock *lock) * Description * Acquire a spinlock represented by the pointer *lock*, which is * stored as part of a value of a map. Taking the lock allows to * safely update the rest of the fields in that value. The * spinlock can (and must) later be released with a call to * **bpf_spin_unlock**\ (\ *lock*\ ). * * Spinlocks in BPF programs come with a number of restrictions * and constraints: * * * **bpf_spin_lock** objects are only allowed inside maps of * types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this * list could be extended in the future). * * BTF description of the map is mandatory. * * The BPF program can take ONE lock at a time, since taking two * or more could cause dead locks. * * Only one **struct bpf_spin_lock** is allowed per map element. * * When the lock is taken, calls (either BPF to BPF or helpers) * are not allowed. * * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not * allowed inside a spinlock-ed region. * * The BPF program MUST call **bpf_spin_unlock**\ () to release * the lock, on all execution paths, before it returns. * * The BPF program can access **struct bpf_spin_lock** only via * the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ () * helpers. Loading or storing data into the **struct * bpf_spin_lock** *lock*\ **;** field of a map is not allowed. * * To use the **bpf_spin_lock**\ () helper, the BTF description * of the map value must be a struct and have **struct * bpf_spin_lock** *anyname*\ **;** field at the top level. * Nested lock inside another struct is not allowed. * * The **struct bpf_spin_lock** *lock* field in a map value must * be aligned on a multiple of 4 bytes in that value. * * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy * the **bpf_spin_lock** field to user space. * * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from * a BPF program, do not update the **bpf_spin_lock** field. * * **bpf_spin_lock** cannot be on the stack or inside a * networking packet (it can only be inside of a map values). * * **bpf_spin_lock** is available to root only. * * Tracing programs and socket filter programs cannot use * **bpf_spin_lock**\ () due to insufficient preemption checks * (but this may change in the future). * * **bpf_spin_lock** is not allowed in inner maps of map-in-map. * Return * 0 * * long bpf_spin_unlock(struct bpf_spin_lock *lock) * Description * Release the *lock* previously locked by a call to * **bpf_spin_lock**\ (\ *lock*\ ). * Return * 0 * * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk) * Description * This helper gets a **struct bpf_sock** pointer such * that all the fields in this **bpf_sock** can be accessed. * Return * A **struct bpf_sock** pointer on success, or **NULL** in * case of failure. * * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk) * Description * This helper gets a **struct bpf_tcp_sock** pointer from a * **struct bpf_sock** pointer. * Return * A **struct bpf_tcp_sock** pointer on success, or **NULL** in * case of failure. * * long bpf_skb_ecn_set_ce(struct sk_buff *skb) * Description * Set ECN (Explicit Congestion Notification) field of IP header * to **CE** (Congestion Encountered) if current value is **ECT** * (ECN Capable Transport). Otherwise, do nothing. Works with IPv6 * and IPv4. * Return * 1 if the **CE** flag is set (either by the current helper call * or because it was already present), 0 if it is not set. * * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk) * Description * Return a **struct bpf_sock** pointer in **TCP_LISTEN** state. * **bpf_sk_release**\ () is unnecessary and not allowed. * Return * A **struct bpf_sock** pointer on success, or **NULL** in * case of failure. * * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags) * Description * Look for TCP socket matching *tuple*, optionally in a child * network namespace *netns*. The return value must be checked, * and if non-**NULL**, released via **bpf_sk_release**\ (). * * This function is identical to **bpf_sk_lookup_tcp**\ (), except * that it also returns timewait or request sockets. Use * **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the * full structure. * * This helper is available only if the kernel was compiled with * **CONFIG_NET** configuration option. * Return * Pointer to **struct bpf_sock**, or **NULL** in case of failure. * For sockets with reuseport option, the **struct bpf_sock** * result is from *reuse*\ **->socks**\ [] using the hash of the * tuple. * * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len) * Description * Check whether *iph* and *th* contain a valid SYN cookie ACK for * the listening socket in *sk*. * * *iph* points to the start of the IPv4 or IPv6 header, while * *iph_len* contains **sizeof**\ (**struct iphdr**) or * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* * contains **sizeof**\ (**struct tcphdr**). * Return * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative * error otherwise. * * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags) * Description * Get name of sysctl in /proc/sys/ and copy it into provided by * program buffer *buf* of size *buf_len*. * * The buffer is always NUL terminated, unless it's zero-sized. * * If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is * copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name * only (e.g. "tcp_mem"). * Return * Number of character copied (not including the trailing NUL). * * **-E2BIG** if the buffer wasn't big enough (*buf* will contain * truncated name in this case). * * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len) * Description * Get current value of sysctl as it is presented in /proc/sys * (incl. newline, etc), and copy it as a string into provided * by program buffer *buf* of size *buf_len*. * * The whole value is copied, no matter what file position user * space issued e.g. sys_read at. * * The buffer is always NUL terminated, unless it's zero-sized. * Return * Number of character copied (not including the trailing NUL). * * **-E2BIG** if the buffer wasn't big enough (*buf* will contain * truncated name in this case). * * **-EINVAL** if current value was unavailable, e.g. because * sysctl is uninitialized and read returns -EIO for it. * * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len) * Description * Get new value being written by user space to sysctl (before * the actual write happens) and copy it as a string into * provided by program buffer *buf* of size *buf_len*. * * User space may write new value at file position > 0. * * The buffer is always NUL terminated, unless it's zero-sized. * Return * Number of character copied (not including the trailing NUL). * * **-E2BIG** if the buffer wasn't big enough (*buf* will contain * truncated name in this case). * * **-EINVAL** if sysctl is being read. * * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len) * Description * Override new value being written by user space to sysctl with * value provided by program in buffer *buf* of size *buf_len*. * * *buf* should contain a string in same form as provided by user * space on sysctl write. * * User space may write new value at file position > 0. To override * the whole sysctl value file position should be set to zero. * Return * 0 on success. * * **-E2BIG** if the *buf_len* is too big. * * **-EINVAL** if sysctl is being read. * * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res) * Description * Convert the initial part of the string from buffer *buf* of * size *buf_len* to a long integer according to the given base * and save the result in *res*. * * The string may begin with an arbitrary amount of white space * (as determined by **isspace**\ (3)) followed by a single * optional '**-**' sign. * * Five least significant bits of *flags* encode base, other bits * are currently unused. * * Base must be either 8, 10, 16 or 0 to detect it automatically * similar to user space **strtol**\ (3). * Return * Number of characters consumed on success. Must be positive but * no more than *buf_len*. * * **-EINVAL** if no valid digits were found or unsupported base * was provided. * * **-ERANGE** if resulting value was out of range. * * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res) * Description * Convert the initial part of the string from buffer *buf* of * size *buf_len* to an unsigned long integer according to the * given base and save the result in *res*. * * The string may begin with an arbitrary amount of white space * (as determined by **isspace**\ (3)). * * Five least significant bits of *flags* encode base, other bits * are currently unused. * * Base must be either 8, 10, 16 or 0 to detect it automatically * similar to user space **strtoul**\ (3). * Return * Number of characters consumed on success. Must be positive but * no more than *buf_len*. * * **-EINVAL** if no valid digits were found or unsupported base * was provided. * * **-ERANGE** if resulting value was out of range. * * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags) * Description * Get a bpf-local-storage from a *sk*. * * Logically, it could be thought of getting the value from * a *map* with *sk* as the **key**. From this * perspective, the usage is not much different from * **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this * helper enforces the key must be a full socket and the map must * be a **BPF_MAP_TYPE_SK_STORAGE** also. * * Underneath, the value is stored locally at *sk* instead of * the *map*. The *map* is used as the bpf-local-storage * "type". The bpf-local-storage "type" (i.e. the *map*) is * searched against all bpf-local-storages residing at *sk*. * * *sk* is a kernel **struct sock** pointer for LSM program. * *sk* is a **struct bpf_sock** pointer for other program types. * * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be * used such that a new bpf-local-storage will be * created if one does not exist. *value* can be used * together with **BPF_SK_STORAGE_GET_F_CREATE** to specify * the initial value of a bpf-local-storage. If *value* is * **NULL**, the new bpf-local-storage will be zero initialized. * Return * A bpf-local-storage pointer is returned on success. * * **NULL** if not found or there was an error in adding * a new bpf-local-storage. * * long bpf_sk_storage_delete(struct bpf_map *map, void *sk) * Description * Delete a bpf-local-storage from a *sk*. * Return * 0 on success. * * **-ENOENT** if the bpf-local-storage cannot be found. * **-EINVAL** if sk is not a fullsock (e.g. a request_sock). * * long bpf_send_signal(u32 sig) * Description * Send signal *sig* to the process of the current task. * The signal may be delivered to any of this process's threads. * Return * 0 on success or successfully queued. * * **-EBUSY** if work queue under nmi is full. * * **-EINVAL** if *sig* is invalid. * * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. * * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len) * Description * Try to issue a SYN cookie for the packet with corresponding * IP/TCP headers, *iph* and *th*, on the listening socket in *sk*. * * *iph* points to the start of the IPv4 or IPv6 header, while * *iph_len* contains **sizeof**\ (**struct iphdr**) or * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* * contains the length of the TCP header. * Return * On success, lower 32 bits hold the generated SYN cookie in * followed by 16 bits which hold the MSS value for that cookie, * and the top 16 bits are unused. * * On failure, the returned value is one of the following: * * **-EINVAL** SYN cookie cannot be issued due to error * * **-ENOENT** SYN cookie should not be issued (no SYN flood) * * **-EOPNOTSUPP** kernel configuration does not enable SYN cookies * * **-EPROTONOSUPPORT** IP packet version is not 4 or 6 * * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size) * Description * Write raw *data* blob into a special BPF perf event held by * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf * event must have the following attributes: **PERF_SAMPLE_RAW** * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and * **PERF_COUNT_SW_BPF_OUTPUT** as **config**. * * The *flags* are used to indicate the index in *map* for which * the value must be put, masked with **BPF_F_INDEX_MASK**. * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU** * to indicate that the index of the current CPU core should be * used. * * The value to write, of *size*, is passed through eBPF stack and * pointed by *data*. * * *ctx* is a pointer to in-kernel struct sk_buff. * * This helper is similar to **bpf_perf_event_output**\ () but * restricted to raw_tracepoint bpf programs. * Return * 0 on success, or a negative error in case of failure. * * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr) * Description * Safely attempt to read *size* bytes from user space address * *unsafe_ptr* and store the data in *dst*. * Return * 0 on success, or a negative error in case of failure. * * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) * Description * Safely attempt to read *size* bytes from kernel space address * *unsafe_ptr* and store the data in *dst*. * Return * 0 on success, or a negative error in case of failure. * * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr) * Description * Copy a NUL terminated string from an unsafe user address * *unsafe_ptr* to *dst*. The *size* should include the * terminating NUL byte. In case the string length is smaller than * *size*, the target is not padded with further NUL bytes. If the * string length is larger than *size*, just *size*-1 bytes are * copied and the last byte is set to NUL. * * On success, the length of the copied string is returned. This * makes this helper useful in tracing programs for reading * strings, and more importantly to get its length at runtime. See * the following snippet: * * :: * * SEC("kprobe/sys_open") * void bpf_sys_open(struct pt_regs *ctx) * { * char buf[PATHLEN]; // PATHLEN is defined to 256 * int res = bpf_probe_read_user_str(buf, sizeof(buf), * ctx->di); * * // Consume buf, for example push it to * // userspace via bpf_perf_event_output(); we * // can use res (the string length) as event * // size, after checking its boundaries. * } * * In comparison, using **bpf_probe_read_user**\ () helper here * instead to read the string would require to estimate the length * at compile time, and would often result in copying more memory * than necessary. * * Another useful use case is when parsing individual process * arguments or individual environment variables navigating * *current*\ **->mm->arg_start** and *current*\ * **->mm->env_start**: using this helper and the return value, * one can quickly iterate at the right offset of the memory area. * Return * On success, the strictly positive length of the string, * including the trailing NUL character. On error, a negative * value. * * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr) * Description * Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr* * to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply. * Return * On success, the strictly positive length of the string, including * the trailing NUL character. On error, a negative value. * * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt) * Description * Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**. * *rcv_nxt* is the ack_seq to be sent out. * Return * 0 on success, or a negative error in case of failure. * * long bpf_send_signal_thread(u32 sig) * Description * Send signal *sig* to the thread corresponding to the current task. * Return * 0 on success or successfully queued. * * **-EBUSY** if work queue under nmi is full. * * **-EINVAL** if *sig* is invalid. * * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. * * u64 bpf_jiffies64(void) * Description * Obtain the 64bit jiffies * Return * The 64 bit jiffies * * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags) * Description * For an eBPF program attached to a perf event, retrieve the * branch records (**struct perf_branch_entry**) associated to *ctx* * and store it in the buffer pointed by *buf* up to size * *size* bytes. * Return * On success, number of bytes written to *buf*. On error, a * negative value. * * The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to * instead return the number of bytes required to store all the * branch entries. If this flag is set, *buf* may be NULL. * * **-EINVAL** if arguments invalid or **size** not a multiple * of **sizeof**\ (**struct perf_branch_entry**\ ). * * **-ENOENT** if architecture does not support branch records. * * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size) * Description * Returns 0 on success, values for *pid* and *tgid* as seen from the current * *namespace* will be returned in *nsdata*. * Return * 0 on success, or one of the following in case of failure: * * **-EINVAL** if dev and inum supplied don't match dev_t and inode number * with nsfs of current task, or if dev conversion to dev_t lost high bits. * * **-ENOENT** if pidns does not exists for the current task. * * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size) * Description * Write raw *data* blob into a special BPF perf event held by * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf * event must have the following attributes: **PERF_SAMPLE_RAW** * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and * **PERF_COUNT_SW_BPF_OUTPUT** as **config**. * * The *flags* are used to indicate the index in *map* for which * the value must be put, masked with **BPF_F_INDEX_MASK**. * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU** * to indicate that the index of the current CPU core should be * used. * * The value to write, of *size*, is passed through eBPF stack and * pointed by *data*. * * *ctx* is a pointer to in-kernel struct xdp_buff. * * This helper is similar to **bpf_perf_eventoutput**\ () but * restricted to raw_tracepoint bpf programs. * Return * 0 on success, or a negative error in case of failure. * * u64 bpf_get_netns_cookie(void *ctx) * Description * Retrieve the cookie (generated by the kernel) of the network * namespace the input *ctx* is associated with. The network * namespace cookie remains stable for its lifetime and provides * a global identifier that can be assumed unique. If *ctx* is * NULL, then the helper returns the cookie for the initial * network namespace. The cookie itself is very similar to that * of **bpf_get_socket_cookie**\ () helper, but for network * namespaces instead of sockets. * Return * A 8-byte long opaque number. * * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level) * Description * Return id of cgroup v2 that is ancestor of the cgroup associated * with the current task at the *ancestor_level*. The root cgroup * is at *ancestor_level* zero and each step down the hierarchy * increments the level. If *ancestor_level* == level of cgroup * associated with the current task, then return value will be the * same as that of **bpf_get_current_cgroup_id**\ (). * * The helper is useful to implement policies based on cgroups * that are upper in hierarchy than immediate cgroup associated * with the current task. * * The format of returned id and helper limitations are same as in * **bpf_get_current_cgroup_id**\ (). * Return * The id is returned or 0 in case the id could not be retrieved. * * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags) * Description * Helper is overloaded depending on BPF program type. This * description applies to **BPF_PROG_TYPE_SCHED_CLS** and * **BPF_PROG_TYPE_SCHED_ACT** programs. * * Assign the *sk* to the *skb*. When combined with appropriate * routing configuration to receive the packet towards the socket, * will cause *skb* to be delivered to the specified socket. * Subsequent redirection of *skb* via **bpf_redirect**\ (), * **bpf_clone_redirect**\ () or other methods outside of BPF may * interfere with successful delivery to the socket. * * This operation is only valid from TC ingress path. * * The *flags* argument must be zero. * Return * 0 on success, or a negative error in case of failure: * * **-EINVAL** if specified *flags* are not supported. * * **-ENOENT** if the socket is unavailable for assignment. * * **-ENETUNREACH** if the socket is unreachable (wrong netns). * * **-EOPNOTSUPP** if the operation is not supported, for example * a call from outside of TC ingress. * * **-ESOCKTNOSUPPORT** if the socket type is not supported * (reuseport). * * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags) * Description * Helper is overloaded depending on BPF program type. This * description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs. * * Select the *sk* as a result of a socket lookup. * * For the operation to succeed passed socket must be compatible * with the packet description provided by the *ctx* object. * * L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must * be an exact match. While IP family (**AF_INET** or * **AF_INET6**) must be compatible, that is IPv6 sockets * that are not v6-only can be selected for IPv4 packets. * * Only TCP listeners and UDP unconnected sockets can be * selected. *sk* can also be NULL to reset any previous * selection. * * *flags* argument can combination of following values: * * * **BPF_SK_LOOKUP_F_REPLACE** to override the previous * socket selection, potentially done by a BPF program * that ran before us. * * * **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip * load-balancing within reuseport group for the socket * being selected. * * On success *ctx->sk* will point to the selected socket. * * Return * 0 on success, or a negative errno in case of failure. * * * **-EAFNOSUPPORT** if socket family (*sk->family*) is * not compatible with packet family (*ctx->family*). * * * **-EEXIST** if socket has been already selected, * potentially by another program, and * **BPF_SK_LOOKUP_F_REPLACE** flag was not specified. * * * **-EINVAL** if unsupported flags were specified. * * * **-EPROTOTYPE** if socket L4 protocol * (*sk->protocol*) doesn't match packet protocol * (*ctx->protocol*). * * * **-ESOCKTNOSUPPORT** if socket is not in allowed * state (TCP listening or UDP unconnected). * * u64 bpf_ktime_get_boot_ns(void) * Description * Return the time elapsed since system boot, in nanoseconds. * Does include the time the system was suspended. * See: **clock_gettime**\ (**CLOCK_BOOTTIME**) * Return * Current *ktime*. * * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len) * Description * **bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print * out the format string. * The *m* represents the seq_file. The *fmt* and *fmt_size* are for * the format string itself. The *data* and *data_len* are format string * arguments. The *data* are a **u64** array and corresponding format string * values are stored in the array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* array. * The *data_len* is the size of *data* in bytes. * * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory. * Reading kernel memory may fail due to either invalid address or * valid address but requiring a major memory fault. If reading kernel memory * fails, the string for **%s** will be an empty string, and the ip * address for **%p{i,I}{4,6}** will be 0. Not returning error to * bpf program is consistent with what **bpf_trace_printk**\ () does for now. * Return * 0 on success, or a negative error in case of failure: * * **-EBUSY** if per-CPU memory copy buffer is busy, can try again * by returning 1 from bpf program. * * **-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported. * * **-E2BIG** if *fmt* contains too many format specifiers. * * **-EOVERFLOW** if an overflow happened: The same object will be tried again. * * long bpf_seq_write(struct seq_file *m, const void *data, u32 len) * Description * **bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data. * The *m* represents the seq_file. The *data* and *len* represent the * data to write in bytes. * Return * 0 on success, or a negative error in case of failure: * * **-EOVERFLOW** if an overflow happened: The same object will be tried again. * * u64 bpf_sk_cgroup_id(void *sk) * Description * Return the cgroup v2 id of the socket *sk*. * * *sk* must be a non-**NULL** pointer to a socket, e.g. one * returned from **bpf_sk_lookup_xxx**\ (), * **bpf_sk_fullsock**\ (), etc. The format of returned id is * same as in **bpf_skb_cgroup_id**\ (). * * This helper is available only if the kernel was compiled with * the **CONFIG_SOCK_CGROUP_DATA** configuration option. * Return * The id is returned or 0 in case the id could not be retrieved. * * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level) * Description * Return id of cgroup v2 that is ancestor of cgroup associated * with the *sk* at the *ancestor_level*. The root cgroup is at * *ancestor_level* zero and each step down the hierarchy * increments the level. If *ancestor_level* == level of cgroup * associated with *sk*, then return value will be same as that * of **bpf_sk_cgroup_id**\ (). * * The helper is useful to implement policies based on cgroups * that are upper in hierarchy than immediate cgroup associated * with *sk*. * * The format of returned id and helper limitations are same as in * **bpf_sk_cgroup_id**\ (). * Return * The id is returned or 0 in case the id could not be retrieved. * * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags) * Description * Copy *size* bytes from *data* into a ring buffer *ringbuf*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification * of new data availability is sent. * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return * 0 on success, or a negative error in case of failure. * * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags) * Description * Reserve *size* bytes of payload in a ring buffer *ringbuf*. * Return * Valid pointer with *size* bytes of memory available; NULL, * otherwise. * * void bpf_ringbuf_submit(void *data, u64 flags) * Description * Submit reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification * of new data availability is sent. * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return * Nothing. Always succeeds. * * void bpf_ringbuf_discard(void *data, u64 flags) * Description * Discard reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification * of new data availability is sent. * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return * Nothing. Always succeeds. * * u64 bpf_ringbuf_query(void *ringbuf, u64 flags) * Description * Query various characteristics of provided ring buffer. What * exactly is queries is determined by *flags*: * * * **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed. * * **BPF_RB_RING_SIZE**: The size of ring buffer. * * **BPF_RB_CONS_POS**: Consumer position (can wrap around). * * **BPF_RB_PROD_POS**: Producer(s) position (can wrap around). * * Data returned is just a momentary snapshot of actual values * and could be inaccurate, so this facility should be used to * power heuristics and for reporting, not to make 100% correct * calculation. * Return * Requested value, or 0, if *flags* are not recognized. * * long bpf_csum_level(struct sk_buff *skb, u64 level) * Description * Change the skbs checksum level by one layer up or down, or * reset it entirely to none in order to have the stack perform * checksum validation. The level is applicable to the following * protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of * | ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP | * through **bpf_skb_adjust_room**\ () helper with passing in * **BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one call * to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since * the UDP header is removed. Similarly, an encap of the latter * into the former could be accompanied by a helper call to * **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the * skb is still intended to be processed in higher layers of the * stack instead of just egressing at tc. * * There are three supported level settings at this time: * * * **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs * with CHECKSUM_UNNECESSARY. * * **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs * with CHECKSUM_UNNECESSARY. * * **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and * sets CHECKSUM_NONE to force checksum validation by the stack. * * **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current * skb->csum_level. * Return * 0 on success, or a negative error in case of failure. In the * case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level * is returned or the error code -EACCES in case the skb is not * subject to CHECKSUM_UNNECESSARY. * * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk) * Description * Dynamically cast a *sk* pointer to a *tcp6_sock* pointer. * Return * *sk* if casting is valid, or **NULL** otherwise. * * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk) * Description * Dynamically cast a *sk* pointer to a *tcp_sock* pointer. * Return * *sk* if casting is valid, or **NULL** otherwise. * * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk) * Description * Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer. * Return * *sk* if casting is valid, or **NULL** otherwise. * * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk) * Description * Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer. * Return * *sk* if casting is valid, or **NULL** otherwise. * * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk) * Description * Dynamically cast a *sk* pointer to a *udp6_sock* pointer. * Return * *sk* if casting is valid, or **NULL** otherwise. * * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags) * Description * Return a user or a kernel stack in bpf program provided buffer. * Note: the user stack will only be populated if the *task* is * the current task; all other tasks will return -EOPNOTSUPP. * To achieve this, the helper needs *task*, which is a valid * pointer to **struct task_struct**. To store the stacktrace, the * bpf program provides *buf* with a nonnegative *size*. * * The last argument, *flags*, holds the number of stack frames to * skip (from 0 to 255), masked with * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set * the following flags: * * **BPF_F_USER_STACK** * Collect a user space stack instead of a kernel stack. * The *task* must be the current task. * **BPF_F_USER_BUILD_ID** * Collect buildid+offset instead of ips for user stack, * only valid if **BPF_F_USER_STACK** is also specified. * * **bpf_get_task_stack**\ () can collect up to * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject * to sufficient large buffer size. Note that * this limit can be controlled with the **sysctl** program, and * that it should be manually increased in order to profile long * user stacks (such as stacks for Java programs). To do so, use: * * :: * * # sysctl kernel.perf_event_max_stack=<new value> * Return * The non-negative copied *buf* length equal to or less than * *size* on success, or a negative error in case of failure. * * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags) * Description * Load header option. Support reading a particular TCP header * option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**). * * If *flags* is 0, it will search the option from the * *skops*\ **->skb_data**. The comment in **struct bpf_sock_ops** * has details on what skb_data contains under different * *skops*\ **->op**. * * The first byte of the *searchby_res* specifies the * kind that it wants to search. * * If the searching kind is an experimental kind * (i.e. 253 or 254 according to RFC6994). It also * needs to specify the "magic" which is either * 2 bytes or 4 bytes. It then also needs to * specify the size of the magic by using * the 2nd byte which is "kind-length" of a TCP * header option and the "kind-length" also * includes the first 2 bytes "kind" and "kind-length" * itself as a normal TCP header option also does. * * For example, to search experimental kind 254 with * 2 byte magic 0xeB9F, the searchby_res should be * [ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ]. * * To search for the standard window scale option (3), * the *searchby_res* should be [ 3, 0, 0, .... 0 ]. * Note, kind-length must be 0 for regular option. * * Searching for No-Op (0) and End-of-Option-List (1) are * not supported. * * *len* must be at least 2 bytes which is the minimal size * of a header option. * * Supported flags: * * * **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the * saved_syn packet or the just-received syn packet. * * Return * > 0 when found, the header option is copied to *searchby_res*. * The return value is the total length copied. On failure, a * negative error code is returned: * * **-EINVAL** if a parameter is invalid. * * **-ENOMSG** if the option is not found. * * **-ENOENT** if no syn packet is available when * **BPF_LOAD_HDR_OPT_TCP_SYN** is used. * * **-ENOSPC** if there is not enough space. Only *len* number of * bytes are copied. * * **-EFAULT** on failure to parse the header options in the * packet. * * **-EPERM** if the helper cannot be used under the current * *skops*\ **->op**. * * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags) * Description * Store header option. The data will be copied * from buffer *from* with length *len* to the TCP header. * * The buffer *from* should have the whole option that * includes the kind, kind-length, and the actual * option data. The *len* must be at least kind-length * long. The kind-length does not have to be 4 byte * aligned. The kernel will take care of the padding * and setting the 4 bytes aligned value to th->doff. * * This helper will check for duplicated option * by searching the same option in the outgoing skb. * * This helper can only be called during * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**. * * Return * 0 on success, or negative error in case of failure: * * **-EINVAL** If param is invalid. * * **-ENOSPC** if there is not enough space in the header. * Nothing has been written * * **-EEXIST** if the option already exists. * * **-EFAULT** on failrue to parse the existing header options. * * **-EPERM** if the helper cannot be used under the current * *skops*\ **->op**. * * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags) * Description * Reserve *len* bytes for the bpf header option. The * space will be used by **bpf_store_hdr_opt**\ () later in * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**. * * If **bpf_reserve_hdr_opt**\ () is called multiple times, * the total number of bytes will be reserved. * * This helper can only be called during * **BPF_SOCK_OPS_HDR_OPT_LEN_CB**. * * Return * 0 on success, or negative error in case of failure: * * **-EINVAL** if a parameter is invalid. * * **-ENOSPC** if there is not enough space in the header. * * **-EPERM** if the helper cannot be used under the current * *skops*\ **->op**. * * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags) * Description * Get a bpf_local_storage from an *inode*. * * Logically, it could be thought of as getting the value from * a *map* with *inode* as the **key**. From this * perspective, the usage is not much different from * **bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this * helper enforces the key must be an inode and the map must also * be a **BPF_MAP_TYPE_INODE_STORAGE**. * * Underneath, the value is stored locally at *inode* instead of * the *map*. The *map* is used as the bpf-local-storage * "type". The bpf-local-storage "type" (i.e. the *map*) is * searched against all bpf_local_storage residing at *inode*. * * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be * used such that a new bpf_local_storage will be * created if one does not exist. *value* can be used * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify * the initial value of a bpf_local_storage. If *value* is * **NULL**, the new bpf_local_storage will be zero initialized. * Return * A bpf_local_storage pointer is returned on success. * * **NULL** if not found or there was an error in adding * a new bpf_local_storage. * * int bpf_inode_storage_delete(struct bpf_map *map, void *inode) * Description * Delete a bpf_local_storage from an *inode*. * Return * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. * * long bpf_d_path(struct path *path, char *buf, u32 sz) * Description * Return full path for given **struct path** object, which * needs to be the kernel BTF *path* object. The path is * returned in the provided buffer *buf* of size *sz* and * is zero terminated. * * Return * On success, the strictly positive length of the string, * including the trailing NUL character. On error, a negative * value. * * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr) * Description * Read *size* bytes from user space address *user_ptr* and store * the data in *dst*. This is a wrapper of **copy_from_user**\ (). * Return * 0 on success, or a negative error in case of failure. * * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags) * Description * Use BTF to store a string representation of *ptr*->ptr in *str*, * using *ptr*->type_id. This value should specify the type * that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1) * can be used to look up vmlinux BTF type ids. Traversing the * data structure using BTF, the type information and values are * stored in the first *str_size* - 1 bytes of *str*. Safe copy of * the pointer data is carried out to avoid kernel crashes during * operation. Smaller types can use string space on the stack; * larger programs can use map data to store the string * representation. * * The string can be subsequently shared with userspace via * bpf_perf_event_output() or ring buffer interfaces. * bpf_trace_printk() is to be avoided as it places too small * a limit on string size to be useful. * * *flags* is a combination of * * **BTF_F_COMPACT** * no formatting around type information * **BTF_F_NONAME** * no struct/union member names/types * **BTF_F_PTR_RAW** * show raw (unobfuscated) pointer values; * equivalent to printk specifier %px. * **BTF_F_ZERO** * show zero-valued struct/union members; they * are not displayed by default * * Return * The number of bytes that were written (or would have been * written if output had to be truncated due to string size), * or a negative error in cases of failure. * * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags) * Description * Use BTF to write to seq_write a string representation of * *ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf(). * *flags* are identical to those used for bpf_snprintf_btf. * Return * 0 on success or a negative error in case of failure. * * u64 bpf_skb_cgroup_classid(struct sk_buff *skb) * Description * See **bpf_get_cgroup_classid**\ () for the main description. * This helper differs from **bpf_get_cgroup_classid**\ () in that * the cgroup v1 net_cls class is retrieved only from the *skb*'s * associated socket instead of the current process. * Return * The id is returned or 0 in case the id could not be retrieved. * * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags) * Description * Redirect the packet to another net device of index *ifindex* * and fill in L2 addresses from neighboring subsystem. This helper * is somewhat similar to **bpf_redirect**\ (), except that it * populates L2 addresses as well, meaning, internally, the helper * relies on the neighbor lookup for the L2 address of the nexthop. * * The helper will perform a FIB lookup based on the skb's * networking header to get the address of the next hop, unless * this is supplied by the caller in the *params* argument. The * *plen* argument indicates the len of *params* and should be set * to 0 if *params* is NULL. * * The *flags* argument is reserved and must be 0. The helper is * currently only supported for tc BPF program types, and enabled * for IPv4 and IPv6 protocols. * Return * The helper returns **TC_ACT_REDIRECT** on success or * **TC_ACT_SHOT** on error. * * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu) * Description * Take a pointer to a percpu ksym, *percpu_ptr*, and return a * pointer to the percpu kernel variable on *cpu*. A ksym is an * extern variable decorated with '__ksym'. For ksym, there is a * global var (either static or global) defined of the same name * in the kernel. The ksym is percpu if the global var is percpu. * The returned pointer points to the global percpu var on *cpu*. * * bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the * kernel, except that bpf_per_cpu_ptr() may return NULL. This * happens if *cpu* is larger than nr_cpu_ids. The caller of * bpf_per_cpu_ptr() must check the returned value. * Return * A pointer pointing to the kernel percpu variable on *cpu*, or * NULL, if *cpu* is invalid. * * void *bpf_this_cpu_ptr(const void *percpu_ptr) * Description * Take a pointer to a percpu ksym, *percpu_ptr*, and return a * pointer to the percpu kernel variable on this cpu. See the * description of 'ksym' in **bpf_per_cpu_ptr**\ (). * * bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in * the kernel. Different from **bpf_per_cpu_ptr**\ (), it would * never return NULL. * Return * A pointer pointing to the kernel percpu variable on this cpu. * * long bpf_redirect_peer(u32 ifindex, u64 flags) * Description * Redirect the packet to another net device of index *ifindex*. * This helper is somewhat similar to **bpf_redirect**\ (), except * that the redirection happens to the *ifindex*' peer device and * the netns switch takes place from ingress to ingress without * going through the CPU's backlog queue. * * The *flags* argument is reserved and must be 0. The helper is * currently only supported for tc BPF program types at the ingress * hook and for veth device types. The peer device must reside in a * different network namespace. * Return * The helper returns **TC_ACT_REDIRECT** on success or * **TC_ACT_SHOT** on error. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ FN(map_lookup_elem), \ FN(map_update_elem), \ FN(map_delete_elem), \ FN(probe_read), \ FN(ktime_get_ns), \ FN(trace_printk), \ FN(get_prandom_u32), \ FN(get_smp_processor_id), \ FN(skb_store_bytes), \ FN(l3_csum_replace), \ FN(l4_csum_replace), \ FN(tail_call), \ FN(clone_redirect), \ FN(get_current_pid_tgid), \ FN(get_current_uid_gid), \ FN(get_current_comm), \ FN(get_cgroup_classid), \ FN(skb_vlan_push), \ FN(skb_vlan_pop), \ FN(skb_get_tunnel_key), \ FN(skb_set_tunnel_key), \ FN(perf_event_read), \ FN(redirect), \ FN(get_route_realm), \ FN(perf_event_output), \ FN(skb_load_bytes), \ FN(get_stackid), \ FN(csum_diff), \ FN(skb_get_tunnel_opt), \ FN(skb_set_tunnel_opt), \ FN(skb_change_proto), \ FN(skb_change_type), \ FN(skb_under_cgroup), \ FN(get_hash_recalc), \ FN(get_current_task), \ FN(probe_write_user), \ FN(current_task_under_cgroup), \ FN(skb_change_tail), \ FN(skb_pull_data), \ FN(csum_update), \ FN(set_hash_invalid), \ FN(get_numa_node_id), \ FN(skb_change_head), \ FN(xdp_adjust_head), \ FN(probe_read_str), \ FN(get_socket_cookie), \ FN(get_socket_uid), \ FN(set_hash), \ FN(setsockopt), \ FN(skb_adjust_room), \ FN(redirect_map), \ FN(sk_redirect_map), \ FN(sock_map_update), \ FN(xdp_adjust_meta), \ FN(perf_event_read_value), \ FN(perf_prog_read_value), \ FN(getsockopt), \ FN(override_return), \ FN(sock_ops_cb_flags_set), \ FN(msg_redirect_map), \ FN(msg_apply_bytes), \ FN(msg_cork_bytes), \ FN(msg_pull_data), \ FN(bind), \ FN(xdp_adjust_tail), \ FN(skb_get_xfrm_state), \ FN(get_stack), \ FN(skb_load_bytes_relative), \ FN(fib_lookup), \ FN(sock_hash_update), \ FN(msg_redirect_hash), \ FN(sk_redirect_hash), \ FN(lwt_push_encap), \ FN(lwt_seg6_store_bytes), \ FN(lwt_seg6_adjust_srh), \ FN(lwt_seg6_action), \ FN(rc_repeat), \ FN(rc_keydown), \ FN(skb_cgroup_id), \ FN(get_current_cgroup_id), \ FN(get_local_storage), \ FN(sk_select_reuseport), \ FN(skb_ancestor_cgroup_id), \ FN(sk_lookup_tcp), \ FN(sk_lookup_udp), \ FN(sk_release), \ FN(map_push_elem), \ FN(map_pop_elem), \ FN(map_peek_elem), \ FN(msg_push_data), \ FN(msg_pop_data), \ FN(rc_pointer_rel), \ FN(spin_lock), \ FN(spin_unlock), \ FN(sk_fullsock), \ FN(tcp_sock), \ FN(skb_ecn_set_ce), \ FN(get_listener_sock), \ FN(skc_lookup_tcp), \ FN(tcp_check_syncookie), \ FN(sysctl_get_name), \ FN(sysctl_get_current_value), \ FN(sysctl_get_new_value), \ FN(sysctl_set_new_value), \ FN(strtol), \ FN(strtoul), \ FN(sk_storage_get), \ FN(sk_storage_delete), \ FN(send_signal), \ FN(tcp_gen_syncookie), \ FN(skb_output), \ FN(probe_read_user), \ FN(probe_read_kernel), \ FN(probe_read_user_str), \ FN(probe_read_kernel_str), \ FN(tcp_send_ack), \ FN(send_signal_thread), \ FN(jiffies64), \ FN(read_branch_records), \ FN(get_ns_current_pid_tgid), \ FN(xdp_output), \ FN(get_netns_cookie), \ FN(get_current_ancestor_cgroup_id), \ FN(sk_assign), \ FN(ktime_get_boot_ns), \ FN(seq_printf), \ FN(seq_write), \ FN(sk_cgroup_id), \ FN(sk_ancestor_cgroup_id), \ FN(ringbuf_output), \ FN(ringbuf_reserve), \ FN(ringbuf_submit), \ FN(ringbuf_discard), \ FN(ringbuf_query), \ FN(csum_level), \ FN(skc_to_tcp6_sock), \ FN(skc_to_tcp_sock), \ FN(skc_to_tcp_timewait_sock), \ FN(skc_to_tcp_request_sock), \ FN(skc_to_udp6_sock), \ FN(get_task_stack), \ FN(load_hdr_opt), \ FN(store_hdr_opt), \ FN(reserve_hdr_opt), \ FN(inode_storage_get), \ FN(inode_storage_delete), \ FN(d_path), \ FN(copy_from_user), \ FN(snprintf_btf), \ FN(seq_printf_btf), \ FN(skb_cgroup_classid), \ FN(redirect_neigh), \ FN(per_cpu_ptr), \ FN(this_cpu_ptr), \ FN(redirect_peer), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call */ #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x enum bpf_func_id { __BPF_FUNC_MAPPER(__BPF_ENUM_FN) __BPF_FUNC_MAX_ID, }; #undef __BPF_ENUM_FN /* All flags used by eBPF helper functions, placed here. */ /* BPF_FUNC_skb_store_bytes flags. */ enum { BPF_F_RECOMPUTE_CSUM = (1ULL << 0), BPF_F_INVALIDATE_HASH = (1ULL << 1), }; /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags. * First 4 bits are for passing the header field size. */ enum { BPF_F_HDR_FIELD_MASK = 0xfULL, }; /* BPF_FUNC_l4_csum_replace flags. */ enum { BPF_F_PSEUDO_HDR = (1ULL << 4), BPF_F_MARK_MANGLED_0 = (1ULL << 5), BPF_F_MARK_ENFORCE = (1ULL << 6), }; /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */ enum { BPF_F_INGRESS = (1ULL << 0), }; /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */ enum { BPF_F_TUNINFO_IPV6 = (1ULL << 0), }; /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */ enum { BPF_F_SKIP_FIELD_MASK = 0xffULL, BPF_F_USER_STACK = (1ULL << 8), /* flags used by BPF_FUNC_get_stackid only. */ BPF_F_FAST_STACK_CMP = (1ULL << 9), BPF_F_REUSE_STACKID = (1ULL << 10), /* flags used by BPF_FUNC_get_stack only. */ BPF_F_USER_BUILD_ID = (1ULL << 11), }; /* BPF_FUNC_skb_set_tunnel_key flags. */ enum { BPF_F_ZERO_CSUM_TX = (1ULL << 1), BPF_F_DONT_FRAGMENT = (1ULL << 2), BPF_F_SEQ_NUMBER = (1ULL << 3), }; /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and * BPF_FUNC_perf_event_read_value flags. */ enum { BPF_F_INDEX_MASK = 0xffffffffULL, BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK, /* BPF_FUNC_perf_event_output for sk_buff input context. */ BPF_F_CTXLEN_MASK = (0xfffffULL << 32), }; /* Current network namespace */ enum { BPF_F_CURRENT_NETNS = (-1L), }; /* BPF_FUNC_csum_level level values. */ enum { BPF_CSUM_LEVEL_QUERY, BPF_CSUM_LEVEL_INC, BPF_CSUM_LEVEL_DEC, BPF_CSUM_LEVEL_RESET, }; /* BPF_FUNC_skb_adjust_room flags. */ enum { BPF_F_ADJ_ROOM_FIXED_GSO = (1ULL << 0), BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 = (1ULL << 1), BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 = (1ULL << 2), BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (1ULL << 3), BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (1ULL << 4), BPF_F_ADJ_ROOM_NO_CSUM_RESET = (1ULL << 5), }; enum { BPF_ADJ_ROOM_ENCAP_L2_MASK = 0xff, BPF_ADJ_ROOM_ENCAP_L2_SHIFT = 56, }; #define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \ BPF_ADJ_ROOM_ENCAP_L2_MASK) \ << BPF_ADJ_ROOM_ENCAP_L2_SHIFT) /* BPF_FUNC_sysctl_get_name flags. */ enum { BPF_F_SYSCTL_BASE_NAME = (1ULL << 0), }; /* BPF_FUNC_<kernel_obj>_storage_get flags */ enum { BPF_LOCAL_STORAGE_GET_F_CREATE = (1ULL << 0), /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead. */ BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE, }; /* BPF_FUNC_read_branch_records flags. */ enum { BPF_F_GET_BRANCH_RECORDS_SIZE = (1ULL << 0), }; /* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and * BPF_FUNC_bpf_ringbuf_output flags. */ enum { BPF_RB_NO_WAKEUP = (1ULL << 0), BPF_RB_FORCE_WAKEUP = (1ULL << 1), }; /* BPF_FUNC_bpf_ringbuf_query flags */ enum { BPF_RB_AVAIL_DATA = 0, BPF_RB_RING_SIZE = 1, BPF_RB_CONS_POS = 2, BPF_RB_PROD_POS = 3, }; /* BPF ring buffer constants */ enum { BPF_RINGBUF_BUSY_BIT = (1U << 31), BPF_RINGBUF_DISCARD_BIT = (1U << 30), BPF_RINGBUF_HDR_SZ = 8, }; /* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */ enum { BPF_SK_LOOKUP_F_REPLACE = (1ULL << 0), BPF_SK_LOOKUP_F_NO_REUSEPORT = (1ULL << 1), }; /* Mode for BPF_FUNC_skb_adjust_room helper. */ enum bpf_adj_room_mode { BPF_ADJ_ROOM_NET, BPF_ADJ_ROOM_MAC, }; /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */ enum bpf_hdr_start_off { BPF_HDR_START_MAC, BPF_HDR_START_NET, }; /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */ enum bpf_lwt_encap_mode { BPF_LWT_ENCAP_SEG6, BPF_LWT_ENCAP_SEG6_INLINE, BPF_LWT_ENCAP_IP, }; #define __bpf_md_ptr(type, name) \ union { \ type name; \ __u64 :64; \ } __attribute__((aligned(8))) /* user accessible mirror of in-kernel sk_buff. * new fields can only be added to the end of this structure */ struct __sk_buff { __u32 len; __u32 pkt_type; __u32 mark; __u32 queue_mapping; __u32 protocol; __u32 vlan_present; __u32 vlan_tci; __u32 vlan_proto; __u32 priority; __u32 ingress_ifindex; __u32 ifindex; __u32 tc_index; __u32 cb[5]; __u32 hash; __u32 tc_classid; __u32 data; __u32 data_end; __u32 napi_id; /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */ __u32 family; __u32 remote_ip4; /* Stored in network byte order */ __u32 local_ip4; /* Stored in network byte order */ __u32 remote_ip6[4]; /* Stored in network byte order */ __u32 local_ip6[4]; /* Stored in network byte order */ __u32 remote_port; /* Stored in network byte order */ __u32 local_port; /* stored in host byte order */ /* ... here. */ __u32 data_meta; __bpf_md_ptr(struct bpf_flow_keys *, flow_keys); __u64 tstamp; __u32 wire_len; __u32 gso_segs; __bpf_md_ptr(struct bpf_sock *, sk); __u32 gso_size; }; struct bpf_tunnel_key { __u32 tunnel_id; union { __u32 remote_ipv4; __u32 remote_ipv6[4]; }; __u8 tunnel_tos; __u8 tunnel_ttl; __u16 tunnel_ext; /* Padding, future use. */ __u32 tunnel_label; }; /* user accessible mirror of in-kernel xfrm_state. * new fields can only be added to the end of this structure */ struct bpf_xfrm_state { __u32 reqid; __u32 spi; /* Stored in network byte order */ __u16 family; __u16 ext; /* Padding, future use. */ union { __u32 remote_ipv4; /* Stored in network byte order */ __u32 remote_ipv6[4]; /* Stored in network byte order */ }; }; /* Generic BPF return codes which all BPF program types may support. * The values are binary compatible with their TC_ACT_* counter-part to * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT * programs. * * XDP is handled seprately, see XDP_*. */ enum bpf_ret_code { BPF_OK = 0, /* 1 reserved */ BPF_DROP = 2, /* 3-6 reserved */ BPF_REDIRECT = 7, /* >127 are reserved for prog type specific return codes. * * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and * BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been * changed and should be routed based on its new L3 header. * (This is an L3 redirect, as opposed to L2 redirect * represented by BPF_REDIRECT above). */ BPF_LWT_REROUTE = 128, }; struct bpf_sock { __u32 bound_dev_if; __u32 family; __u32 type; __u32 protocol; __u32 mark; __u32 priority; /* IP address also allows 1 and 2 bytes access */ __u32 src_ip4; __u32 src_ip6[4]; __u32 src_port; /* host byte order */ __be16 dst_port; /* network byte order */ __u16 :16; /* zero padding */ __u32 dst_ip4; __u32 dst_ip6[4]; __u32 state; __s32 rx_queue_mapping; }; struct bpf_tcp_sock { __u32 snd_cwnd; /* Sending congestion window */ __u32 srtt_us; /* smoothed round trip time << 3 in usecs */ __u32 rtt_min; __u32 snd_ssthresh; /* Slow start size threshold */ __u32 rcv_nxt; /* What we want to receive next */ __u32 snd_nxt; /* Next sequence we send */ __u32 snd_una; /* First byte we want an ack for */ __u32 mss_cache; /* Cached effective mss, not including SACKS */ __u32 ecn_flags; /* ECN status bits. */ __u32 rate_delivered; /* saved rate sample: packets delivered */ __u32 rate_interval_us; /* saved rate sample: time elapsed */ __u32 packets_out; /* Packets which are "in flight" */ __u32 retrans_out; /* Retransmitted packets out */ __u32 total_retrans; /* Total retransmits for entire connection */ __u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn * total number of segments in. */ __u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn * total number of data segments in. */ __u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut * The total number of segments sent. */ __u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut * total number of data segments sent. */ __u32 lost_out; /* Lost packets */ __u32 sacked_out; /* SACK'd packets */ __u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived * sum(delta(rcv_nxt)), or how many bytes * were acked. */ __u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked * sum(delta(snd_una)), or how many bytes * were acked. */ __u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups * total number of DSACK blocks received */ __u32 delivered; /* Total data packets delivered incl. rexmits */ __u32 delivered_ce; /* Like the above but only ECE marked packets */ __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */ }; struct bpf_sock_tuple { union { struct { __be32 saddr; __be32 daddr; __be16 sport; __be16 dport; } ipv4; struct { __be32 saddr[4]; __be32 daddr[4]; __be16 sport; __be16 dport; } ipv6; }; }; struct bpf_xdp_sock { __u32 queue_id; }; #define XDP_PACKET_HEADROOM 256 /* User return codes for XDP prog type. * A valid XDP program must return one of these defined values. All other * return codes are reserved for future use. Unknown return codes will * result in packet drops and a warning via bpf_warn_invalid_xdp_action(). */ enum xdp_action { XDP_ABORTED = 0, XDP_DROP, XDP_PASS, XDP_TX, XDP_REDIRECT, }; /* user accessible metadata for XDP packet hook * new fields must be added to the end of this structure */ struct xdp_md { __u32 data; __u32 data_end; __u32 data_meta; /* Below access go through struct xdp_rxq_info */ __u32 ingress_ifindex; /* rxq->dev->ifindex */ __u32 rx_queue_index; /* rxq->queue_index */ __u32 egress_ifindex; /* txq->dev->ifindex */ }; /* DEVMAP map-value layout * * The struct data-layout of map-value is a configuration interface. * New members can only be added to the end of this structure. */ struct bpf_devmap_val { __u32 ifindex; /* device index */ union { int fd; /* prog fd on map write */ __u32 id; /* prog id on map read */ } bpf_prog; }; /* CPUMAP map-value layout * * The struct data-layout of map-value is a configuration interface. * New members can only be added to the end of this structure. */ struct bpf_cpumap_val { __u32 qsize; /* queue size to remote target CPU */ union { int fd; /* prog fd on map write */ __u32 id; /* prog id on map read */ } bpf_prog; }; enum sk_action { SK_DROP = 0, SK_PASS, }; /* user accessible metadata for SK_MSG packet hook, new fields must * be added to the end of this structure */ struct sk_msg_md { __bpf_md_ptr(void *, data); __bpf_md_ptr(void *, data_end); __u32 family; __u32 remote_ip4; /* Stored in network byte order */ __u32 local_ip4; /* Stored in network byte order */ __u32 remote_ip6[4]; /* Stored in network byte order */ __u32 local_ip6[4]; /* Stored in network byte order */ __u32 remote_port; /* Stored in network byte order */ __u32 local_port; /* stored in host byte order */ __u32 size; /* Total size of sk_msg */ __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */ }; struct sk_reuseport_md { /* * Start of directly accessible data. It begins from * the tcp/udp header. */ __bpf_md_ptr(void *, data); /* End of directly accessible data */ __bpf_md_ptr(void *, data_end); /* * Total length of packet (starting from the tcp/udp header). * Note that the directly accessible bytes (data_end - data) * could be less than this "len". Those bytes could be * indirectly read by a helper "bpf_skb_load_bytes()". */ __u32 len; /* * Eth protocol in the mac header (network byte order). e.g. * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD) */ __u32 eth_protocol; __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */ __u32 bind_inany; /* Is sock bound to an INANY address? */ __u32 hash; /* A hash of the packet 4 tuples */ }; #define BPF_TAG_SIZE 8 struct bpf_prog_info { __u32 type; __u32 id; __u8 tag[BPF_TAG_SIZE]; __u32 jited_prog_len; __u32 xlated_prog_len; __aligned_u64 jited_prog_insns; __aligned_u64 xlated_prog_insns; __u64 load_time; /* ns since boottime */ __u32 created_by_uid; __u32 nr_map_ids; __aligned_u64 map_ids; char name[BPF_OBJ_NAME_LEN]; __u32 ifindex; __u32 gpl_compatible:1; __u32 :31; /* alignment pad */ __u64 netns_dev; __u64 netns_ino; __u32 nr_jited_ksyms; __u32 nr_jited_func_lens; __aligned_u64 jited_ksyms; __aligned_u64 jited_func_lens; __u32 btf_id; __u32 func_info_rec_size; __aligned_u64 func_info; __u32 nr_func_info; __u32 nr_line_info; __aligned_u64 line_info; __aligned_u64 jited_line_info; __u32 nr_jited_line_info; __u32 line_info_rec_size; __u32 jited_line_info_rec_size; __u32 nr_prog_tags; __aligned_u64 prog_tags; __u64 run_time_ns; __u64 run_cnt; } __attribute__((aligned(8))); struct bpf_map_info { __u32 type; __u32 id; __u32 key_size; __u32 value_size; __u32 max_entries; __u32 map_flags; char name[BPF_OBJ_NAME_LEN]; __u32 ifindex; __u32 btf_vmlinux_value_type_id; __u64 netns_dev; __u64 netns_ino; __u32 btf_id; __u32 btf_key_type_id; __u32 btf_value_type_id; } __attribute__((aligned(8))); struct bpf_btf_info { __aligned_u64 btf; __u32 btf_size; __u32 id; } __attribute__((aligned(8))); struct bpf_link_info { __u32 type; __u32 id; __u32 prog_id; union { struct { __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */ __u32 tp_name_len; /* in/out: tp_name buffer len */ } raw_tracepoint; struct { __u32 attach_type; } tracing; struct { __u64 cgroup_id; __u32 attach_type; } cgroup; struct { __aligned_u64 target_name; /* in/out: target_name buffer ptr */ __u32 target_name_len; /* in/out: target_name buffer len */ union { struct { __u32 map_id; } map; }; } iter; struct { __u32 netns_ino; __u32 attach_type; } netns; struct { __u32 ifindex; } xdp; }; } __attribute__((aligned(8))); /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed * by user and intended to be used by socket (e.g. to bind to, depends on * attach type). */ struct bpf_sock_addr { __u32 user_family; /* Allows 4-byte read, but no write. */ __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write. * Stored in network byte order. */ __u32 user_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write. * Stored in network byte order. */ __u32 user_port; /* Allows 1,2,4-byte read and 4-byte write. * Stored in network byte order */ __u32 family; /* Allows 4-byte read, but no write */ __u32 type; /* Allows 4-byte read, but no write */ __u32 protocol; /* Allows 4-byte read, but no write */ __u32 msg_src_ip4; /* Allows 1,2,4-byte read and 4-byte write. * Stored in network byte order. */ __u32 msg_src_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write. * Stored in network byte order. */ __bpf_md_ptr(struct bpf_sock *, sk); }; /* User bpf_sock_ops struct to access socket values and specify request ops * and their replies. * Some of this fields are in network (bigendian) byte order and may need * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h). * New fields can only be added at the end of this structure */ struct bpf_sock_ops { __u32 op; union { __u32 args[4]; /* Optionally passed to bpf program */ __u32 reply; /* Returned by bpf program */ __u32 replylong[4]; /* Optionally returned by bpf prog */ }; __u32 family; __u32 remote_ip4; /* Stored in network byte order */ __u32 local_ip4; /* Stored in network byte order */ __u32 remote_ip6[4]; /* Stored in network byte order */ __u32 local_ip6[4]; /* Stored in network byte order */ __u32 remote_port; /* Stored in network byte order */ __u32 local_port; /* stored in host byte order */ __u32 is_fullsock; /* Some TCP fields are only valid if * there is a full socket. If not, the * fields read as zero. */ __u32 snd_cwnd; __u32 srtt_us; /* Averaged RTT << 3 in usecs */ __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */ __u32 state; __u32 rtt_min; __u32 snd_ssthresh; __u32 rcv_nxt; __u32 snd_nxt; __u32 snd_una; __u32 mss_cache; __u32 ecn_flags; __u32 rate_delivered; __u32 rate_interval_us; __u32 packets_out; __u32 retrans_out; __u32 total_retrans; __u32 segs_in; __u32 data_segs_in; __u32 segs_out; __u32 data_segs_out; __u32 lost_out; __u32 sacked_out; __u32 sk_txhash; __u64 bytes_received; __u64 bytes_acked; __bpf_md_ptr(struct bpf_sock *, sk); /* [skb_data, skb_data_end) covers the whole TCP header. * * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received * BPF_SOCK_OPS_HDR_OPT_LEN_CB: Not useful because the * header has not been written. * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have * been written so far. * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: The SYNACK that concludes * the 3WHS. * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes * the 3WHS. * * bpf_load_hdr_opt() can also be used to read a particular option. */ __bpf_md_ptr(void *, skb_data); __bpf_md_ptr(void *, skb_data_end); __u32 skb_len; /* The total length of a packet. * It includes the header, options, * and payload. */ __u32 skb_tcp_flags; /* tcp_flags of the header. It provides * an easy way to check for tcp_flags * without parsing skb_data. * * In particular, the skb_tcp_flags * will still be available in * BPF_SOCK_OPS_HDR_OPT_LEN even though * the outgoing header has not * been written yet. */ }; /* Definitions for bpf_sock_ops_cb_flags */ enum { BPF_SOCK_OPS_RTO_CB_FLAG = (1<<0), BPF_SOCK_OPS_RETRANS_CB_FLAG = (1<<1), BPF_SOCK_OPS_STATE_CB_FLAG = (1<<2), BPF_SOCK_OPS_RTT_CB_FLAG = (1<<3), /* Call bpf for all received TCP headers. The bpf prog will be * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB * * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB * for the header option related helpers that will be useful * to the bpf programs. * * It could be used at the client/active side (i.e. connect() side) * when the server told it that the server was in syncookie * mode and required the active side to resend the bpf-written * options. The active side can keep writing the bpf-options until * it received a valid packet from the server side to confirm * the earlier packet (and options) has been received. The later * example patch is using it like this at the active side when the * server is in syncookie mode. * * The bpf prog will usually turn this off in the common cases. */ BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG = (1<<4), /* Call bpf when kernel has received a header option that * the kernel cannot handle. The bpf prog will be called under * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB. * * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB * for the header option related helpers that will be useful * to the bpf programs. */ BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5), /* Call bpf when the kernel is writing header options for the * outgoing packet. The bpf prog will first be called * to reserve space in a skb under * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB. Then * the bpf prog will be called to write the header option(s) * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB. * * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option * related helpers that will be useful to the bpf programs. * * The kernel gets its chance to reserve space and write * options first before the BPF program does. */ BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6), /* Mask of all currently supported cb flags */ BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F, }; /* List of known BPF sock_ops operators. * New entries can only be added at the end */ enum { BPF_SOCK_OPS_VOID, BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or * -1 if default value should be used */ BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized * window (in packets) or -1 if default * value should be used */ BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an * active connection is initialized */ BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an * active connection is * established */ BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a * passive connection is * established */ BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control * needs ECN */ BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is * based on the path and may be * dependent on the congestion control * algorithm. In general it indicates * a congestion threshold. RTTs above * this indicate congestion */ BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered. * Arg1: value of icsk_retransmits * Arg2: value of icsk_rto * Arg3: whether RTO has expired */ BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted. * Arg1: sequence number of 1st byte * Arg2: # segments * Arg3: return value of * tcp_transmit_skb (0 => success) */ BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state. * Arg1: old_state * Arg2: new_state */ BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after * socket transition to LISTEN state. */ BPF_SOCK_OPS_RTT_CB, /* Called on every RTT. */ BPF_SOCK_OPS_PARSE_HDR_OPT_CB, /* Parse the header option. * It will be called to handle * the packets received at * an already established * connection. * * sock_ops->skb_data: * Referring to the received skb. * It covers the TCP header only. * * bpf_load_hdr_opt() can also * be used to search for a * particular option. */ BPF_SOCK_OPS_HDR_OPT_LEN_CB, /* Reserve space for writing the * header option later in * BPF_SOCK_OPS_WRITE_HDR_OPT_CB. * Arg1: bool want_cookie. (in * writing SYNACK only) * * sock_ops->skb_data: * Not available because no header has * been written yet. * * sock_ops->skb_tcp_flags: * The tcp_flags of the * outgoing skb. (e.g. SYN, ACK, FIN). * * bpf_reserve_hdr_opt() should * be used to reserve space. */ BPF_SOCK_OPS_WRITE_HDR_OPT_CB, /* Write the header options * Arg1: bool want_cookie. (in * writing SYNACK only) * * sock_ops->skb_data: * Referring to the outgoing skb. * It covers the TCP header * that has already been written * by the kernel and the * earlier bpf-progs. * * sock_ops->skb_tcp_flags: * The tcp_flags of the outgoing * skb. (e.g. SYN, ACK, FIN). * * bpf_store_hdr_opt() should * be used to write the * option. * * bpf_load_hdr_opt() can also * be used to search for a * particular option that * has already been written * by the kernel or the * earlier bpf-progs. */ }; /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect * changes between the TCP and BPF versions. Ideally this should never happen. * If it does, we need to add code to convert them before calling * the BPF sock_ops function. */ enum { BPF_TCP_ESTABLISHED = 1, BPF_TCP_SYN_SENT, BPF_TCP_SYN_RECV, BPF_TCP_FIN_WAIT1, BPF_TCP_FIN_WAIT2, BPF_TCP_TIME_WAIT, BPF_TCP_CLOSE, BPF_TCP_CLOSE_WAIT, BPF_TCP_LAST_ACK, BPF_TCP_LISTEN, BPF_TCP_CLOSING, /* Now a valid state */ BPF_TCP_NEW_SYN_RECV, BPF_TCP_MAX_STATES /* Leave at the end! */ }; enum { TCP_BPF_IW = 1001, /* Set TCP initial congestion window */ TCP_BPF_SNDCWND_CLAMP = 1002, /* Set sndcwnd_clamp */ TCP_BPF_DELACK_MAX = 1003, /* Max delay ack in usecs */ TCP_BPF_RTO_MIN = 1004, /* Min delay ack in usecs */ /* Copy the SYN pkt to optval * * BPF_PROG_TYPE_SOCK_OPS only. It is similar to the * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit * to only getting from the saved_syn. It can either get the * syn packet from: * * 1. the just-received SYN packet (only available when writing the * SYNACK). It will be useful when it is not necessary to * save the SYN packet for latter use. It is also the only way * to get the SYN during syncookie mode because the syn * packet cannot be saved during syncookie. * * OR * * 2. the earlier saved syn which was done by * bpf_setsockopt(TCP_SAVE_SYN). * * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the * SYN packet is obtained. * * If the bpf-prog does not need the IP[46] header, the * bpf-prog can avoid parsing the IP header by using * TCP_BPF_SYN. Otherwise, the bpf-prog can get both * IP[46] and TCP header by using TCP_BPF_SYN_IP. * * >0: Total number of bytes copied * -ENOSPC: Not enough space in optval. Only optlen number of * bytes is copied. * -ENOENT: The SYN skb is not available now and the earlier SYN pkt * is not saved by setsockopt(TCP_SAVE_SYN). */ TCP_BPF_SYN = 1005, /* Copy the TCP header */ TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */ TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */ }; enum { BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0), }; /* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and * BPF_SOCK_OPS_WRITE_HDR_OPT_CB. */ enum { BPF_WRITE_HDR_TCP_CURRENT_MSS = 1, /* Kernel is finding the * total option spaces * required for an established * sk in order to calculate the * MSS. No skb is actually * sent. */ BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2, /* Kernel is in syncookie mode * when sending a SYN. */ }; struct bpf_perf_event_value { __u64 counter; __u64 enabled; __u64 running; }; enum { BPF_DEVCG_ACC_MKNOD = (1ULL << 0), BPF_DEVCG_ACC_READ = (1ULL << 1), BPF_DEVCG_ACC_WRITE = (1ULL << 2), }; enum { BPF_DEVCG_DEV_BLOCK = (1ULL << 0), BPF_DEVCG_DEV_CHAR = (1ULL << 1), }; struct bpf_cgroup_dev_ctx { /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */ __u32 access_type; __u32 major; __u32 minor; }; struct bpf_raw_tracepoint_args { __u64 args[0]; }; /* DIRECT: Skip the FIB rules and go to FIB table associated with device * OUTPUT: Do lookup from egress perspective; default is ingress */ enum { BPF_FIB_LOOKUP_DIRECT = (1U << 0), BPF_FIB_LOOKUP_OUTPUT = (1U << 1), }; enum { BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */ BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */ BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */ BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */ BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */ BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */ BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */ BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */ BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */ }; struct bpf_fib_lookup { /* input: network family for lookup (AF_INET, AF_INET6) * output: network family of egress nexthop */ __u8 family; /* set if lookup is to consider L4 data - e.g., FIB rules */ __u8 l4_protocol; __be16 sport; __be16 dport; /* total length of packet from network header - used for MTU check */ __u16 tot_len; /* input: L3 device index for lookup * output: device index from FIB lookup */ __u32 ifindex; union { /* inputs to lookup */ __u8 tos; /* AF_INET */ __be32 flowinfo; /* AF_INET6, flow_label + priority */ /* output: metric of fib result (IPv4/IPv6 only) */ __u32 rt_metric; }; union { __be32 ipv4_src; __u32 ipv6_src[4]; /* in6_addr; network order */ }; /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in * network header. output: bpf_fib_lookup sets to gateway address * if FIB lookup returns gateway route */ union { __be32 ipv4_dst; __u32 ipv6_dst[4]; /* in6_addr; network order */ }; /* output */ __be16 h_vlan_proto; __be16 h_vlan_TCI; __u8 smac[6]; /* ETH_ALEN */ __u8 dmac[6]; /* ETH_ALEN */ }; struct bpf_redir_neigh { /* network family for lookup (AF_INET, AF_INET6) */ __u32 nh_family; /* network address of nexthop; skips fib lookup to find gateway */ union { __be32 ipv4_nh; __u32 ipv6_nh[4]; /* in6_addr; network order */ }; }; enum bpf_task_fd_type { BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */ BPF_FD_TYPE_TRACEPOINT, /* tp name */ BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */ BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */ BPF_FD_TYPE_UPROBE, /* filename + offset */ BPF_FD_TYPE_URETPROBE, /* filename + offset */ }; enum { BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG = (1U << 0), BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL = (1U << 1), BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP = (1U << 2), }; struct bpf_flow_keys { __u16 nhoff; __u16 thoff; __u16 addr_proto; /* ETH_P_* of valid addrs */ __u8 is_frag; __u8 is_first_frag; __u8 is_encap; __u8 ip_proto; __be16 n_proto; __be16 sport; __be16 dport; union { struct { __be32 ipv4_src; __be32 ipv4_dst; }; struct { __u32 ipv6_src[4]; /* in6_addr; network order */ __u32 ipv6_dst[4]; /* in6_addr; network order */ }; }; __u32 flags; __be32 flow_label; }; struct bpf_func_info { __u32 insn_off; __u32 type_id; }; #define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10) #define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff) struct bpf_line_info { __u32 insn_off; __u32 file_name_off; __u32 line_off; __u32 line_col; }; struct bpf_spin_lock { __u32 val; }; struct bpf_sysctl { __u32 write; /* Sysctl is being read (= 0) or written (= 1). * Allows 1,2,4-byte read, but no write. */ __u32 file_pos; /* Sysctl file position to read from, write to. * Allows 1,2,4-byte read an 4-byte write. */ }; struct bpf_sockopt { __bpf_md_ptr(struct bpf_sock *, sk); __bpf_md_ptr(void *, optval); __bpf_md_ptr(void *, optval_end); __s32 level; __s32 optname; __s32 optlen; __s32 retval; }; struct bpf_pidns_info { __u32 pid; __u32 tgid; }; /* User accessible data for SK_LOOKUP programs. Add new fields at the end. */ struct bpf_sk_lookup { union { __bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */ __u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */ }; __u32 family; /* Protocol family (AF_INET, AF_INET6) */ __u32 protocol; /* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */ __u32 remote_ip4; /* Network byte order */ __u32 remote_ip6[4]; /* Network byte order */ __u32 remote_port; /* Network byte order */ __u32 local_ip4; /* Network byte order */ __u32 local_ip6[4]; /* Network byte order */ __u32 local_port; /* Host byte order */ }; /* * struct btf_ptr is used for typed pointer representation; the * type id is used to render the pointer data as the appropriate type * via the bpf_snprintf_btf() helper described above. A flags field - * potentially to specify additional details about the BTF pointer * (rather than its mode of display) - is included for future use. * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately. */ struct btf_ptr { void *ptr; __u32 type_id; __u32 flags; /* BTF ptr flags; unused at present. */ }; /* * Flags to control bpf_snprintf_btf() behaviour. * - BTF_F_COMPACT: no formatting around type information * - BTF_F_NONAME: no struct/union member names/types * - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values; * equivalent to %px. * - BTF_F_ZERO: show zero-valued struct/union members; they * are not displayed by default */ enum { BTF_F_COMPACT = (1ULL << 0), BTF_F_NONAME = (1ULL << 1), BTF_F_PTR_RAW = (1ULL << 2), BTF_F_ZERO = (1ULL << 3), }; #endif /* __LINUX_BPF_H__ */