/contrib/bind9/lib/isc/unix/ifiter_sysctl.c

  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	if (ifam->ifam_type == RTM_IFINFO) {
163		struct if_msghdr *ifm = (struct if_msghdr *) ifam;
164		struct sockaddr_dl *sdl = (struct sockaddr_dl *) (ifm + 1);
165		unsigned int namelen;
166
167		memset(&iter->current, 0, sizeof(iter->current));
168
169		namelen = sdl->sdl_nlen;
170		if (namelen > sizeof(iter->current.name) - 1)
171			namelen = sizeof(iter->current.name) - 1;
172
173		memset(iter->current.name, 0, sizeof(iter->current.name));
174		memcpy(iter->current.name, sdl->sdl_data, namelen);
175
176		iter->current.flags = 0;
177
178		if ((ifam->ifam_flags & IFF_UP) != 0)
179			iter->current.flags |= INTERFACE_F_UP;
180
181		if ((ifam->ifam_flags & IFF_POINTOPOINT) != 0)
182			iter->current.flags |= INTERFACE_F_POINTTOPOINT;
183
184		if ((ifam->ifam_flags & IFF_LOOPBACK) != 0)
185			iter->current.flags |= INTERFACE_F_LOOPBACK;
186
187		/*
188		 * This is not an interface address.
189		 * Force another iteration.
190		 */
191		return (ISC_R_IGNORE);
192	} else if (ifam->ifam_type == RTM_NEWADDR) {
193		int i;
194		int family;
195		struct sockaddr *mask_sa = NULL;
196		struct sockaddr *addr_sa = NULL;
197		struct sockaddr *dst_sa = NULL;
198
199		struct sockaddr *sa = (struct sockaddr *)(ifam + 1);
200		family = sa->sa_family;
201
202		for (i = 0; i < RTAX_MAX; i++)
203		{
204			if ((ifam->ifam_addrs & (1 << i)) == 0)
205				continue;
206
207			INSIST(sa < (struct sockaddr *) ifam_end);
208
209			switch (i) {
210			case RTAX_NETMASK: /* Netmask */
211				mask_sa = sa;
212				break;
213			case RTAX_IFA: /* Interface address */
214				addr_sa = sa;
215				break;
216			case RTAX_BRD: /* Broadcast or destination address */
217				dst_sa = sa;
218				break;
219			}
220#ifdef ISC_PLATFORM_HAVESALEN
221			sa = (struct sockaddr *)((char*)(sa)
222					 + ROUNDUP(sa->sa_len));
223#else
224#ifdef sgi
225			/*
226			 * Do as the contributed SGI code does.
227			 */
228			sa = (struct sockaddr *)((char*)(sa)
229					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
230#else
231			/* XXX untested. */
232			sa = (struct sockaddr *)((char*)(sa)
233					 + ROUNDUP(sizeof(struct sockaddr)));
234#endif
235#endif
236		}
237
238		if (addr_sa == NULL)
239			return (ISC_R_IGNORE);
240
241		family = addr_sa->sa_family;
242		if (family != AF_INET && family != AF_INET6)
243			return (ISC_R_IGNORE);
244
245		iter->current.af = family;
246
247		get_addr(family, &iter->current.address, addr_sa,
248			 iter->current.name);
249
250		if (mask_sa != NULL)
251			get_addr(family, &iter->current.netmask, mask_sa,
252				 iter->current.name);
253
254		if (dst_sa != NULL &&
255		    (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
256			get_addr(family, &iter->current.dstaddress, dst_sa,
257				 iter->current.name);
258
259		return (ISC_R_SUCCESS);
260	} else {
261		printf(isc_msgcat_get(isc_msgcat, ISC_MSGSET_IFITERSYSCTL,
262				      ISC_MSG_UNEXPECTEDTYPE,
263				      "warning: unexpected interface list "
264				      "message type\n"));
265		return (ISC_R_IGNORE);
266	}
267}
268
269/*
270 * Step the iterator to the next interface.  Unlike
271 * isc_interfaceiter_next(), this may leave the iterator
272 * positioned on an interface that will ultimately
273 * be ignored.  Return ISC_R_NOMORE if there are no more
274 * interfaces, otherwise ISC_R_SUCCESS.
275 */
276static isc_result_t
277internal_next(isc_interfaceiter_t *iter) {
278	struct ifa_msghdr *ifam;
279	REQUIRE (iter->pos < (unsigned int) iter->bufused);
280
281	ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
282
283	iter->pos += ifam->ifam_msglen;
284
285	if (iter->pos >= iter->bufused)
286		return (ISC_R_NOMORE);
287
288	return (ISC_R_SUCCESS);
289}
290
291static void
292internal_destroy(isc_interfaceiter_t *iter) {
293	UNUSED(iter); /* Unused. */
294	/*
295	 * Do nothing.
296	 */
297}
298
299static
300void internal_first(isc_interfaceiter_t *iter) {
301	iter->pos = 0;
302}