ifiter_sysctl.c revision 290001 
1/*
2 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2003  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_sysctl.c,v 1.25 2007/06/19 23:47:18 tbox Exp $ */
19
20/*! \file
21 * \brief
22 * Obtain the list of network interfaces using sysctl.
23 * See TCP/IP Illustrated Volume 2, sections 19.8, 19.14,
24 * and 19.16.
25 */
26
27#include <sys/param.h>
28#include <sys/sysctl.h>
29
30#include <net/route.h>
31#include <net/if_dl.h>
32
33/* XXX what about Alpha? */
34#ifdef sgi
35#define ROUNDUP(a) ((a) > 0 ? \
36		(1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) : \
37		sizeof(__uint64_t))
38#else
39#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
40                    : sizeof(long))
41#endif
42
43#define IFITER_MAGIC		ISC_MAGIC('I', 'F', 'I', 'S')
44#define VALID_IFITER(t)		ISC_MAGIC_VALID(t, IFITER_MAGIC)
45
46struct isc_interfaceiter {
47	unsigned int		magic;		/* Magic number. */
48	isc_mem_t		*mctx;
49	void			*buf;		/* Buffer for sysctl data. */
50	unsigned int		bufsize;	/* Bytes allocated. */
51	unsigned int		bufused;	/* Bytes used. */
52	unsigned int		pos;		/* Current offset in
53						   sysctl data. */
54	isc_interface_t		current;	/* Current interface data. */
55	isc_result_t		result;		/* Last result code. */
56};
57
58static int mib[6] = {
59	CTL_NET,
60	PF_ROUTE,
61        0,
62	0, 			/* Any address family. */
63        NET_RT_IFLIST,
64	0 			/* Flags. */
65};
66
67isc_result_t
68isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
69	isc_interfaceiter_t *iter;
70	isc_result_t result;
71	size_t bufsize;
72	size_t bufused;
73	char strbuf[ISC_STRERRORSIZE];
74
75	REQUIRE(mctx != NULL);
76	REQUIRE(iterp != NULL);
77	REQUIRE(*iterp == NULL);
78
79	iter = isc_mem_get(mctx, sizeof(*iter));
80	if (iter == NULL)
81		return (ISC_R_NOMEMORY);
82
83	iter->mctx = mctx;
84	iter->buf = 0;
85
86	/*
87	 * Determine the amount of memory needed.
88	 */
89	bufsize = 0;
90	if (sysctl(mib, 6, NULL, &bufsize, NULL, (size_t) 0) < 0) {
91		isc__strerror(errno, strbuf, sizeof(strbuf));
92		UNEXPECTED_ERROR(__FILE__, __LINE__,
93				 isc_msgcat_get(isc_msgcat,
94						ISC_MSGSET_IFITERSYSCTL,
95						ISC_MSG_GETIFLISTSIZE,
96						"getting interface "
97						"list size: sysctl: %s"),
98				 strbuf);
99		result = ISC_R_UNEXPECTED;
100		goto failure;
101	}
102	iter->bufsize = bufsize;
103
104	iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
105	if (iter->buf == NULL) {
106		result = ISC_R_NOMEMORY;
107		goto failure;
108	}
109
110	bufused = bufsize;
111	if (sysctl(mib, 6, iter->buf, &bufused, NULL, (size_t) 0) < 0) {
112		isc__strerror(errno, strbuf, sizeof(strbuf));
113		UNEXPECTED_ERROR(__FILE__, __LINE__,
114				 isc_msgcat_get(isc_msgcat,
115						ISC_MSGSET_IFITERSYSCTL,
116						ISC_MSG_GETIFLIST,
117						"getting interface list: "
118						"sysctl: %s"),
119				 strbuf);
120		result = ISC_R_UNEXPECTED;
121		goto failure;
122	}
123	iter->bufused = bufused;
124	INSIST(iter->bufused <= iter->bufsize);
125
126	/*
127	 * A newly created iterator has an undefined position
128	 * until isc_interfaceiter_first() is called.
129	 */
130	iter->pos = (unsigned int) -1;
131	iter->result = ISC_R_FAILURE;
132
133	iter->magic = IFITER_MAGIC;
134	*iterp = iter;
135	return (ISC_R_SUCCESS);
136
137 failure:
138	if (iter->buf != NULL)
139		isc_mem_put(mctx, iter->buf, iter->bufsize);
140	isc_mem_put(mctx, iter, sizeof(*iter));
141	return (result);
142}
143
144/*
145 * Get information about the current interface to iter->current.
146 * If successful, return ISC_R_SUCCESS.
147 * If the interface has an unsupported address family,
148 * return ISC_R_IGNORE.  In case of other failure,
149 * return ISC_R_UNEXPECTED.
150 */
151
152static isc_result_t
153internal_current(isc_interfaceiter_t *iter) {
154	struct ifa_msghdr *ifam, *ifam_end;
155
156	REQUIRE(VALID_IFITER(iter));
157	REQUIRE (iter->pos < (unsigned int) iter->bufused);
158
159	ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
160	ifam_end = (struct ifa_msghdr *) ((char *) iter->buf + iter->bufused);
161
162	// Skip wrong RTM version headers
163	if (ifam->ifam_version != RTM_VERSION)
164		return (ISC_R_IGNORE);
165
166	if (ifam->ifam_type == RTM_IFINFO) {
167		struct if_msghdr *ifm = (struct if_msghdr *) ifam;
168		struct sockaddr_dl *sdl = (struct sockaddr_dl *) (ifm + 1);
169		unsigned int namelen;
170
171		memset(&iter->current, 0, sizeof(iter->current));
172
173		iter->current.ifindex = sdl->sdl_index;
174		namelen = sdl->sdl_nlen;
175		if (namelen > sizeof(iter->current.name) - 1)
176			namelen = sizeof(iter->current.name) - 1;
177
178		memset(iter->current.name, 0, sizeof(iter->current.name));
179		memcpy(iter->current.name, sdl->sdl_data, namelen);
180
181		iter->current.flags = 0;
182
183		if ((ifam->ifam_flags & IFF_UP) != 0)
184			iter->current.flags |= INTERFACE_F_UP;
185
186		if ((ifam->ifam_flags & IFF_POINTOPOINT) != 0)
187			iter->current.flags |= INTERFACE_F_POINTTOPOINT;
188
189		if ((ifam->ifam_flags & IFF_LOOPBACK) != 0)
190			iter->current.flags |= INTERFACE_F_LOOPBACK;
191
192		if ((ifam->ifam_flags & IFF_BROADCAST) != 0)
193			iter->current.flags |= INTERFACE_F_BROADCAST;
194
195#ifdef IFF_MULTICAST
196		if ((ifam->ifam_flags & IFF_MULTICAST) != 0)
197			iter->current.flags |= INTERFACE_F_MULTICAST;
198#endif
199
200		/*
201		 * This is not an interface address.
202		 * Force another iteration.
203		 */
204		return (ISC_R_IGNORE);
205	} else if (ifam->ifam_type == RTM_NEWADDR) {
206		int i;
207		int family;
208		struct sockaddr *mask_sa = NULL;
209		struct sockaddr *addr_sa = NULL;
210		struct sockaddr *dst_sa = NULL;
211
212		struct sockaddr *sa = (struct sockaddr *)(ifam + 1);
213		family = sa->sa_family;
214
215		for (i = 0; i < RTAX_MAX; i++)
216		{
217			if ((ifam->ifam_addrs & (1 << i)) == 0)
218				continue;
219
220			INSIST(sa < (struct sockaddr *) ifam_end);
221
222			switch (i) {
223			case RTAX_NETMASK: /* Netmask */
224				mask_sa = sa;
225				break;
226			case RTAX_IFA: /* Interface address */
227				addr_sa = sa;
228				break;
229			case RTAX_BRD: /* Broadcast or destination address */
230				dst_sa = sa;
231				break;
232			}
233#ifdef ISC_PLATFORM_HAVESALEN
234			sa = (struct sockaddr *)((char*)(sa)
235					 + ROUNDUP(sa->sa_len));
236#else
237#ifdef sgi
238			/*
239			 * Do as the contributed SGI code does.
240			 */
241			sa = (struct sockaddr *)((char*)(sa)
242					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
243#else
244			/* XXX untested. */
245			sa = (struct sockaddr *)((char*)(sa)
246					 + ROUNDUP(sizeof(struct sockaddr)));
247#endif
248#endif
249		}
250
251		if (addr_sa == NULL)
252			return (ISC_R_IGNORE);
253
254		family = addr_sa->sa_family;
255		if (family != AF_INET && family != AF_INET6)
256			return (ISC_R_IGNORE);
257
258		iter->current.af = family;
259
260		get_addr(family, &iter->current.address, addr_sa,
261			 iter->current.name);
262
263		if (mask_sa != NULL)
264			get_addr(family, &iter->current.netmask, mask_sa,
265				 iter->current.name);
266
267		if (dst_sa != NULL &&
268		    (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
269			get_addr(family, &iter->current.dstaddress, dst_sa,
270				 iter->current.name);
271
272		if (dst_sa != NULL &&
273		    (iter->current.flags & INTERFACE_F_BROADCAST) != 0)
274			get_addr(family, &iter->current.broadcast, dst_sa,
275				 iter->current.name);
276
277		return (ISC_R_SUCCESS);
278	} else {
279		printf("%s", isc_msgcat_get(isc_msgcat,
280					    ISC_MSGSET_IFITERSYSCTL,
281					    ISC_MSG_UNEXPECTEDTYPE,
282					    "warning: unexpected interface "
283					    "list message type\n"));
284		return (ISC_R_IGNORE);
285	}
286}
287
288/*
289 * Step the iterator to the next interface.  Unlike
290 * isc_interfaceiter_next(), this may leave the iterator
291 * positioned on an interface that will ultimately
292 * be ignored.  Return ISC_R_NOMORE if there are no more
293 * interfaces, otherwise ISC_R_SUCCESS.
294 */
295static isc_result_t
296internal_next(isc_interfaceiter_t *iter) {
297	struct ifa_msghdr *ifam;
298	REQUIRE (iter->pos < (unsigned int) iter->bufused);
299
300	ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
301
302	iter->pos += ifam->ifam_msglen;
303
304	if (iter->pos >= iter->bufused)
305		return (ISC_R_NOMORE);
306
307	return (ISC_R_SUCCESS);
308}
309
310static void
311internal_destroy(isc_interfaceiter_t *iter) {
312	UNUSED(iter); /* Unused. */
313	/*
314	 * Do nothing.
315	 */
316}
317
318static
319void internal_first(isc_interfaceiter_t *iter) {
320	iter->pos = 0;
321}
322