1 | /* ifaddrs.h -- declarations for getting network interface addresses |
2 | Copyright (C) 2002-2018 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, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #ifndef _IFADDRS_H |
20 | #define _IFADDRS_H 1 |
21 | |
22 | #include <features.h> |
23 | #include <sys/socket.h> |
24 | |
25 | __BEGIN_DECLS |
26 | |
27 | /* The `getifaddrs' function generates a linked list of these structures. |
28 | Each element of the list describes one network interface. */ |
29 | struct ifaddrs |
30 | { |
31 | struct ifaddrs *ifa_next; /* Pointer to the next structure. */ |
32 | |
33 | char *ifa_name; /* Name of this network interface. */ |
34 | unsigned int ifa_flags; /* Flags as from SIOCGIFFLAGS ioctl. */ |
35 | |
36 | struct sockaddr *ifa_addr; /* Network address of this interface. */ |
37 | struct sockaddr *ifa_netmask; /* Netmask of this interface. */ |
38 | union |
39 | { |
40 | /* At most one of the following two is valid. If the IFF_BROADCAST |
41 | bit is set in `ifa_flags', then `ifa_broadaddr' is valid. If the |
42 | IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid. |
43 | It is never the case that both these bits are set at once. */ |
44 | struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */ |
45 | struct sockaddr *ifu_dstaddr; /* Point-to-point destination address. */ |
46 | } ifa_ifu; |
47 | /* These very same macros are defined by <net/if.h> for `struct ifaddr'. |
48 | So if they are defined already, the existing definitions will be fine. */ |
49 | # ifndef ifa_broadaddr |
50 | # define ifa_broadaddr ifa_ifu.ifu_broadaddr |
51 | # endif |
52 | # ifndef ifa_dstaddr |
53 | # define ifa_dstaddr ifa_ifu.ifu_dstaddr |
54 | # endif |
55 | |
56 | void *ifa_data; /* Address-specific data (may be unused). */ |
57 | }; |
58 | |
59 | |
60 | /* Create a linked list of `struct ifaddrs' structures, one for each |
61 | network interface on the host machine. If successful, store the |
62 | list in *IFAP and return 0. On errors, return -1 and set `errno'. |
63 | |
64 | The storage returned in *IFAP is allocated dynamically and can |
65 | only be properly freed by passing it to `freeifaddrs'. */ |
66 | extern int getifaddrs (struct ifaddrs **__ifap) __THROW; |
67 | |
68 | /* Reclaim the storage allocated by a previous `getifaddrs' call. */ |
69 | extern void freeifaddrs (struct ifaddrs *__ifa) __THROW; |
70 | |
71 | __END_DECLS |
72 | |
73 | #endif /* ifaddrs.h */ |
74 | |