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lh9ed821d2023-04-07 01:36:19 -07001/* ifaddrs.h -- declarations for getting network interface addresses
2 Copyright (C) 2002 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
19
20#ifndef _IFADDRS_H
21#define _IFADDRS_H 1
22
23#include <features.h>
24#include <sys/socket.h>
25
26__BEGIN_DECLS
27
28/* The `getifaddrs' function generates a linked list of these structures.
29 Each element of the list describes one network interface. */
30struct ifaddrs
31{
32 struct ifaddrs *ifa_next; /* Pointer to the next structure. */
33
34 char *ifa_name; /* Name of this network interface. */
35 unsigned int ifa_flags; /* Flags as from SIOCGIFFLAGS ioctl. */
36
37 struct sockaddr *ifa_addr; /* Network address of this interface. */
38 struct sockaddr *ifa_netmask; /* Netmask of this interface. */
39 union
40 {
41 /* At most one of the following two is valid. If the IFF_BROADCAST
42 bit is set in `ifa_flags', then `ifa_broadaddr' is valid. If the
43 IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid.
44 It is never the case that both these bits are set at once. */
45 struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */
46 struct sockaddr *ifu_dstaddr; /* Point-to-point destination address. */
47 } ifa_ifu;
48 /* These very same macros are defined by <net/if.h> for `struct ifaddr'.
49 So if they are defined already, the existing definitions will be fine. */
50# ifndef ifa_broadaddr
51# define ifa_broadaddr ifa_ifu.ifu_broadaddr
52# endif
53# ifndef ifa_dstaddr
54# define ifa_dstaddr ifa_ifu.ifu_dstaddr
55# endif
56
57 void *ifa_data; /* Address-specific data (may be unused). */
58};
59
60
61/* Create a linked list of `struct ifaddrs' structures, one for each
62 network interface on the host machine. If successful, store the
63 list in *IFAP and return 0. On errors, return -1 and set `errno'.
64
65 The storage returned in *IFAP is allocated dynamically and can
66 only be properly freed by passing it to `freeifaddrs'. */
67extern int getifaddrs (struct ifaddrs **__ifap) __THROW;
68libc_hidden_proto(getifaddrs)
69
70/* Reclaim the storage allocated by a previous `getifaddrs' call. */
71extern void freeifaddrs (struct ifaddrs *__ifa) __THROW;
72libc_hidden_proto(freeifaddrs)
73
74__END_DECLS
75
76#endif /* ifaddrs.h */