/* ifaddrs.h -- declarations for getting network interface addresses Copyright (C) 2002-2020 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ #ifndef _IFADDRS_H #define _IFADDRS_H 1 #include <features.h> #include <sys/socket.h> __BEGIN_DECLS /* The `getifaddrs' function generates a linked list of these structures. Each element of the list describes one network interface. */ struct ifaddrs { struct ifaddrs *ifa_next; /* Pointer to the next structure. */ char *ifa_name; /* Name of this network interface. */ unsigned int ifa_flags; /* Flags as from SIOCGIFFLAGS ioctl. */ struct sockaddr *ifa_addr; /* Network address of this interface. */ struct sockaddr *ifa_netmask; /* Netmask of this interface. */ union { /* At most one of the following two is valid. If the IFF_BROADCAST bit is set in `ifa_flags', then `ifa_broadaddr' is valid. If the IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid. It is never the case that both these bits are set at once. */ struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */ struct sockaddr *ifu_dstaddr; /* Point-to-point destination address. */ } ifa_ifu; /* These very same macros are defined by <net/if.h> for `struct ifaddr'. So if they are defined already, the existing definitions will be fine. */ # ifndef ifa_broadaddr # define ifa_broadaddr ifa_ifu.ifu_broadaddr # endif # ifndef ifa_dstaddr # define ifa_dstaddr ifa_ifu.ifu_dstaddr # endif void *ifa_data; /* Address-specific data (may be unused). */ }; /* Create a linked list of `struct ifaddrs' structures, one for each network interface on the host machine. If successful, store the list in *IFAP and return 0. On errors, return -1 and set `errno'. The storage returned in *IFAP is allocated dynamically and can only be properly freed by passing it to `freeifaddrs'. */ extern int getifaddrs (struct ifaddrs **__ifap) __THROW; /* Reclaim the storage allocated by a previous `getifaddrs' call. */ extern void freeifaddrs (struct ifaddrs *__ifa) __THROW; __END_DECLS #endif /* ifaddrs.h */