ifiter_getifaddrs.c revision 282408 
1/*
2 * Copyright (C) 2004, 2005, 2007-2009  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2003  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: ifiter_getifaddrs.c,v 1.13 2009/09/24 23:48:13 tbox Exp $ */
19
20/*! \file
21 * \brief
22 * Obtain the list of network interfaces using the getifaddrs(3) library.
23 */
24
25#include <ifaddrs.h>
26
27/*% Iterator Magic */
28#define IFITER_MAGIC		ISC_MAGIC('I', 'F', 'I', 'G')
29/*% Valid Iterator */
30#define VALID_IFITER(t)		ISC_MAGIC_VALID(t, IFITER_MAGIC)
31
32#ifdef __linux
33static isc_boolean_t seenv6 = ISC_FALSE;
34#endif
35
36/*% Iterator structure */
37struct isc_interfaceiter {
38	unsigned int		magic;		/*%< Magic number. */
39	isc_mem_t		*mctx;
40	void			*buf;		/*%< (unused) */
41	unsigned int		bufsize;	/*%< (always 0) */
42	struct ifaddrs		*ifaddrs;	/*%< List of ifaddrs */
43	struct ifaddrs		*pos;		/*%< Ptr to current ifaddr */
44	isc_interface_t		current;	/*%< Current interface data. */
45	isc_result_t		result;		/*%< Last result code. */
46#ifdef  __linux
47	FILE *                  proc;
48	char                    entry[ISC_IF_INET6_SZ];
49	isc_result_t            valid;
50#endif
51};
52
53isc_result_t
54isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
55	isc_interfaceiter_t *iter;
56	isc_result_t result;
57	char strbuf[ISC_STRERRORSIZE];
58	int trys, ret;
59
60	REQUIRE(mctx != NULL);
61	REQUIRE(iterp != NULL);
62	REQUIRE(*iterp == NULL);
63
64	iter = isc_mem_get(mctx, sizeof(*iter));
65	if (iter == NULL)
66		return (ISC_R_NOMEMORY);
67
68	iter->mctx = mctx;
69	iter->buf = NULL;
70	iter->bufsize = 0;
71	iter->ifaddrs = NULL;
72#ifdef __linux
73	/*
74	 * Only open "/proc/net/if_inet6" if we have never seen a IPv6
75	 * address returned by getifaddrs().
76	 */
77	if (!seenv6) {
78		iter->proc = fopen("/proc/net/if_inet6", "r");
79		if (iter->proc == NULL) {
80			isc__strerror(errno, strbuf, sizeof(strbuf));
81			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
82				      ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
83				      "failed to open /proc/net/if_inet6");
84		}
85	} else
86		iter->proc = NULL;
87	iter->valid = ISC_R_FAILURE;
88#endif
89
90	/* If interrupted, try again */
91	for (trys = 0; trys < 3; trys++) {
92		if ((ret = getifaddrs(&iter->ifaddrs)) >= 0)
93			break;
94		if (errno != EINTR)
95			break;
96	}
97	if (ret < 0) {
98		isc__strerror(errno, strbuf, sizeof(strbuf));
99		UNEXPECTED_ERROR(__FILE__, __LINE__,
100                		 "getting interface addresses: %s: %s",
101				 isc_msgcat_get(isc_msgcat,
102						ISC_MSGSET_IFITERGETIFADDRS,
103						ISC_MSG_GETIFADDRS,
104						"getifaddrs"),
105				 strbuf);
106		result = ISC_R_UNEXPECTED;
107		goto failure;
108	}
109
110	/*
111	 * A newly created iterator has an undefined position
112	 * until isc_interfaceiter_first() is called.
113	 */
114	iter->pos = NULL;
115	iter->result = ISC_R_FAILURE;
116
117	iter->magic = IFITER_MAGIC;
118	*iterp = iter;
119	return (ISC_R_SUCCESS);
120
121 failure:
122#ifdef __linux
123	if (iter->proc != NULL)
124		fclose(iter->proc);
125#endif
126	if (iter->ifaddrs != NULL) /* just in case */
127		freeifaddrs(iter->ifaddrs);
128	isc_mem_put(mctx, iter, sizeof(*iter));
129	return (result);
130}
131
132/*
133 * Get information about the current interface to iter->current.
134 * If successful, return ISC_R_SUCCESS.
135 * If the interface has an unsupported address family,
136 * return ISC_R_IGNORE.
137 */
138
139static isc_result_t
140internal_current(isc_interfaceiter_t *iter) {
141	struct ifaddrs *ifa;
142	int family;
143	unsigned int namelen;
144
145	REQUIRE(VALID_IFITER(iter));
146
147	ifa = iter->pos;
148
149#ifdef __linux
150	if (iter->pos == NULL)
151		return (linux_if_inet6_current(iter));
152#endif
153
154	INSIST(ifa != NULL);
155	INSIST(ifa->ifa_name != NULL);
156
157	if (ifa->ifa_addr == NULL)
158		return (ISC_R_IGNORE);
159
160	family = ifa->ifa_addr->sa_family;
161	if (family != AF_INET && family != AF_INET6)
162		return (ISC_R_IGNORE);
163
164#ifdef __linux
165	if (family == AF_INET6)
166		seenv6 = ISC_TRUE;
167#endif
168
169	memset(&iter->current, 0, sizeof(iter->current));
170
171	namelen = strlen(ifa->ifa_name);
172	if (namelen > sizeof(iter->current.name) - 1)
173		namelen = sizeof(iter->current.name) - 1;
174
175	memset(iter->current.name, 0, sizeof(iter->current.name));
176	memcpy(iter->current.name, ifa->ifa_name, namelen);
177
178	iter->current.flags = 0;
179
180	if ((ifa->ifa_flags & IFF_UP) != 0)
181		iter->current.flags |= INTERFACE_F_UP;
182
183	if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)
184		iter->current.flags |= INTERFACE_F_POINTTOPOINT;
185
186	if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
187		iter->current.flags |= INTERFACE_F_LOOPBACK;
188
189	if ((ifa->ifa_flags & IFF_BROADCAST) != 0)
190		iter->current.flags |= INTERFACE_F_BROADCAST;
191
192#ifdef IFF_MULTICAST
193	if ((ifa->ifa_flags & IFF_MULTICAST) != 0)
194		iter->current.flags |= INTERFACE_F_MULTICAST;
195#endif
196
197	iter->current.af = family;
198
199	get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);
200
201	if (ifa->ifa_netmask != NULL)
202		get_addr(family, &iter->current.netmask, ifa->ifa_netmask,
203			 ifa->ifa_name);
204
205	if (ifa->ifa_dstaddr != NULL &&
206	    (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
207		get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,
208			 ifa->ifa_name);
209
210	if (ifa->ifa_broadaddr != NULL &&
211	    (iter->current.flags & INTERFACE_F_BROADCAST) != 0)
212		get_addr(family, &iter->current.broadcast, ifa->ifa_broadaddr,
213			 ifa->ifa_name);
214
215#ifdef ISC_PLATFORM_HAVEIFNAMETOINDEX
216	iter->current.ifindex = if_nametoindex(iter->current.name);
217#endif
218	return (ISC_R_SUCCESS);
219}
220
221/*
222 * Step the iterator to the next interface.  Unlike
223 * isc_interfaceiter_next(), this may leave the iterator
224 * positioned on an interface that will ultimately
225 * be ignored.  Return ISC_R_NOMORE if there are no more
226 * interfaces, otherwise ISC_R_SUCCESS.
227 */
228static isc_result_t
229internal_next(isc_interfaceiter_t *iter) {
230
231	if (iter->pos != NULL)
232		iter->pos = iter->pos->ifa_next;
233	if (iter->pos == NULL) {
234#ifdef __linux
235		if (!seenv6)
236			return (linux_if_inet6_next(iter));
237#endif
238		return (ISC_R_NOMORE);
239	}
240
241	return (ISC_R_SUCCESS);
242}
243
244static void
245internal_destroy(isc_interfaceiter_t *iter) {
246
247#ifdef __linux
248	if (iter->proc != NULL)
249		fclose(iter->proc);
250	iter->proc = NULL;
251#endif
252	if (iter->ifaddrs)
253		freeifaddrs(iter->ifaddrs);
254	iter->ifaddrs = NULL;
255}
256
257static
258void internal_first(isc_interfaceiter_t *iter) {
259
260#ifdef __linux
261	linux_if_inet6_first(iter);
262#endif
263	iter->pos = iter->ifaddrs;
264}
265