1 /* Determine protocol families for which interfaces exist. Linux version.
2 Copyright (C) 2003, 2006, 2007 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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
28 #include <sys/socket.h>
30 #include <asm/types.h>
31 #include <linux/netlink.h>
32 #include <linux/rtnetlink.h>
34 #include <not-cancel.h>
35 #include <kernel-features.h>
38 #ifndef IFA_F_TEMPORARY
39 # define IFA_F_TEMPORARY IFA_F_SECONDARY
41 #ifndef IFA_F_HOMEADDRESS
42 # define IFA_F_HOMEADDRESS 0
47 make_request (int fd
, pid_t pid
, bool *seen_ipv4
, bool *seen_ipv6
,
48 struct in6addrinfo
**in6ai
, size_t *in6ailen
)
54 /* struct rtgenmsg consists of a single byte. This means there
55 are three bytes of padding included in the REQ definition.
56 We make them explicit here. */
59 struct sockaddr_nl nladdr
;
61 req
.nlh
.nlmsg_len
= sizeof (req
);
62 req
.nlh
.nlmsg_type
= RTM_GETADDR
;
63 req
.nlh
.nlmsg_flags
= NLM_F_ROOT
| NLM_F_MATCH
| NLM_F_REQUEST
;
64 req
.nlh
.nlmsg_pid
= 0;
65 req
.nlh
.nlmsg_seq
= time (NULL
);
66 req
.g
.rtgen_family
= AF_UNSPEC
;
68 assert (sizeof (req
) - offsetof (struct req
, pad
) == 3);
69 memset (req
.pad
, '\0', sizeof (req
.pad
));
71 memset (&nladdr
, '\0', sizeof (nladdr
));
72 nladdr
.nl_family
= AF_NETLINK
;
75 /* Help the compiler optimize out the malloc call if PAGE_SIZE
76 is constant and smaller or equal to PTHREAD_STACK_MIN/4. */
77 const size_t buf_size
= PAGE_SIZE
;
79 const size_t buf_size
= __getpagesize ();
81 bool use_malloc
= false;
84 if (__libc_use_alloca (buf_size
))
85 buf
= alloca (buf_size
);
88 buf
= malloc (buf_size
);
95 struct iovec iov
= { buf
, buf_size
};
97 if (TEMP_FAILURE_RETRY (__sendto (fd
, (void *) &req
, sizeof (req
), 0,
98 (struct sockaddr
*) &nladdr
,
99 sizeof (nladdr
))) < 0)
108 struct in6addrinfo info
;
109 struct in6ailist
*next
;
111 size_t in6ailistlen
= 0;
117 (void *) &nladdr
, sizeof (nladdr
),
123 ssize_t read_len
= TEMP_FAILURE_RETRY (__recvmsg (fd
, &msg
, 0));
127 if (msg
.msg_flags
& MSG_TRUNC
)
130 struct nlmsghdr
*nlmh
;
131 for (nlmh
= (struct nlmsghdr
*) buf
;
132 NLMSG_OK (nlmh
, (size_t) read_len
);
133 nlmh
= (struct nlmsghdr
*) NLMSG_NEXT (nlmh
, read_len
))
135 if (nladdr
.nl_pid
!= 0 || (pid_t
) nlmh
->nlmsg_pid
!= pid
136 || nlmh
->nlmsg_seq
!= req
.nlh
.nlmsg_seq
)
139 if (nlmh
->nlmsg_type
== RTM_NEWADDR
)
141 struct ifaddrmsg
*ifam
= (struct ifaddrmsg
*) NLMSG_DATA (nlmh
);
142 struct rtattr
*rta
= IFA_RTA (ifam
);
143 size_t len
= nlmh
->nlmsg_len
- NLMSG_LENGTH (sizeof (*ifam
));
145 switch (ifam
->ifa_family
)
153 while (RTA_OK (rta
, len
))
155 switch (rta
->rta_type
)
158 local
= RTA_DATA (rta
);
162 address
= RTA_DATA (rta
);
166 rta
= RTA_NEXT (rta
, len
);
172 if (*(const in_addr_t
*) (address
?: local
)
173 != htonl (INADDR_LOOPBACK
))
181 while (RTA_OK (rta
, len
))
183 switch (rta
->rta_type
)
186 local
= RTA_DATA (rta
);
190 address
= RTA_DATA (rta
);
194 rta
= RTA_NEXT (rta
, len
);
200 if (!IN6_IS_ADDR_LOOPBACK (address
?: local
))
204 if (ifam
->ifa_flags
& (IFA_F_DEPRECATED
206 | IFA_F_HOMEADDRESS
))
208 struct in6ailist
*newp
= alloca (sizeof (*newp
));
209 newp
->info
.flags
= (((ifam
->ifa_flags
& IFA_F_DEPRECATED
)
210 ? in6ai_deprecated
: 0)
213 ? in6ai_temporary
: 0)
216 ? in6ai_homeaddress
: 0));
217 memcpy (newp
->info
.addr
, address
?: local
,
218 sizeof (newp
->info
.addr
));
219 newp
->next
= in6ailist
;
229 else if (nlmh
->nlmsg_type
== NLMSG_DONE
)
230 /* We found the end, leave the loop. */
236 close_not_cancel_no_status (fd
);
238 if (*seen_ipv6
&& in6ailist
!= NULL
)
240 *in6ai
= malloc (in6ailistlen
* sizeof (**in6ai
));
244 *in6ailen
= in6ailistlen
;
248 (*in6ai
)[--in6ailistlen
] = in6ailist
->info
;
249 in6ailist
= in6ailist
->next
;
251 while (in6ailist
!= NULL
);
265 /* We don't know if we have NETLINK support compiled in in our
267 #if __ASSUME_NETLINK_SUPPORT == 0
268 /* Define in ifaddrs.h. */
269 extern int __no_netlink_support attribute_hidden
;
271 # define __no_netlink_support 0
277 __check_pf (bool *seen_ipv4
, bool *seen_ipv6
,
278 struct in6addrinfo
**in6ai
, size_t *in6ailen
)
283 if (! __no_netlink_support
)
285 int fd
= __socket (PF_NETLINK
, SOCK_RAW
, NETLINK_ROUTE
);
287 struct sockaddr_nl nladdr
;
288 memset (&nladdr
, '\0', sizeof (nladdr
));
289 nladdr
.nl_family
= AF_NETLINK
;
291 socklen_t addr_len
= sizeof (nladdr
);
294 && __bind (fd
, (struct sockaddr
*) &nladdr
, sizeof (nladdr
)) == 0
295 && __getsockname (fd
, (struct sockaddr
*) &nladdr
, &addr_len
) == 0
296 && make_request (fd
, nladdr
.nl_pid
, seen_ipv4
, seen_ipv6
,
297 in6ai
, in6ailen
) == 0)
304 #if __ASSUME_NETLINK_SUPPORT == 0
305 /* Remember that there is no netlink support. */
306 __no_netlink_support
= 1;
308 /* We cannot determine what interfaces are available. Be
315 #if __ASSUME_NETLINK_SUPPORT == 0
316 /* No netlink. Get the interface list via getifaddrs. */
317 struct ifaddrs
*ifa
= NULL
;
318 if (getifaddrs (&ifa
) != 0)
320 /* We cannot determine what interfaces are available. Be
327 struct ifaddrs
*runp
;
328 for (runp
= ifa
; runp
!= NULL
; runp
= runp
->ifa_next
)
329 if (runp
->ifa_addr
->sa_family
== PF_INET
)
331 else if (runp
->ifa_addr
->sa_family
== PF_INET6
)
334 (void) freeifaddrs (ifa
);