1/*	$NetBSD: ifiter_sysctl.c,v 1.2.6.1 2012/06/05 21:15:24 bouyer Exp $	*/
2
3/*
4 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (C) 1999-2003  Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
18 */
19
20/* Id: ifiter_sysctl.c,v 1.25 2007/06/19 23:47:18 tbox Exp  */
21
22/*! \file
23 * \brief
24 * Obtain the list of network interfaces using sysctl.
25 * See TCP/IP Illustrated Volume 2, sections 19.8, 19.14,
26 * and 19.16.
27 */
28
29#include <sys/param.h>
30#include <sys/sysctl.h>
31
32#include <net/route.h>
33#include <net/if_dl.h>
34
35/* XXX what about Alpha? */
36#ifdef sgi
37#define ROUNDUP(a) ((a) > 0 ? \
38		(1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) : \
39		sizeof(__uint64_t))
40#else
41#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
42                    : sizeof(long))
43#endif
44
45#define IFITER_MAGIC		ISC_MAGIC('I', 'F', 'I', 'S')
46#define VALID_IFITER(t)		ISC_MAGIC_VALID(t, IFITER_MAGIC)
47
48struct isc_interfaceiter {
49	unsigned int		magic;		/* Magic number. */
50	isc_mem_t		*mctx;
51	void			*buf;		/* Buffer for sysctl data. */
52	unsigned int		bufsize;	/* Bytes allocated. */
53	unsigned int		bufused;	/* Bytes used. */
54	unsigned int		pos;		/* Current offset in
55						   sysctl data. */
56	isc_interface_t		current;	/* Current interface data. */
57	isc_result_t		result;		/* Last result code. */
58};
59
60static int mib[6] = {
61	CTL_NET,
62	PF_ROUTE,
63        0,
64	0, 			/* Any address family. */
65        NET_RT_IFLIST,
66	0 			/* Flags. */
67};
68
69isc_result_t
70isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
71	isc_interfaceiter_t *iter;
72	isc_result_t result;
73	size_t bufsize;
74	size_t bufused;
75	char strbuf[ISC_STRERRORSIZE];
76
77	REQUIRE(mctx != NULL);
78	REQUIRE(iterp != NULL);
79	REQUIRE(*iterp == NULL);
80
81	iter = isc_mem_get(mctx, sizeof(*iter));
82	if (iter == NULL)
83		return (ISC_R_NOMEMORY);
84
85	iter->mctx = mctx;
86	iter->buf = 0;
87
88	/*
89	 * Determine the amount of memory needed.
90	 */
91	bufsize = 0;
92	if (sysctl(mib, 6, NULL, &bufsize, NULL, (size_t) 0) < 0) {
93		isc__strerror(errno, strbuf, sizeof(strbuf));
94		UNEXPECTED_ERROR(__FILE__, __LINE__,
95				 isc_msgcat_get(isc_msgcat,
96						ISC_MSGSET_IFITERSYSCTL,
97						ISC_MSG_GETIFLISTSIZE,
98						"getting interface "
99						"list size: sysctl: %s"),
100				 strbuf);
101		result = ISC_R_UNEXPECTED;
102		goto failure;
103	}
104	iter->bufsize = bufsize;
105
106	iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
107	if (iter->buf == NULL) {
108		result = ISC_R_NOMEMORY;
109		goto failure;
110	}
111
112	bufused = bufsize;
113	if (sysctl(mib, 6, iter->buf, &bufused, NULL, (size_t) 0) < 0) {
114		isc__strerror(errno, strbuf, sizeof(strbuf));
115		UNEXPECTED_ERROR(__FILE__, __LINE__,
116				 isc_msgcat_get(isc_msgcat,
117						ISC_MSGSET_IFITERSYSCTL,
118						ISC_MSG_GETIFLIST,
119						"getting interface list: "
120						"sysctl: %s"),
121				 strbuf);
122		result = ISC_R_UNEXPECTED;
123		goto failure;
124	}
125	iter->bufused = bufused;
126	INSIST(iter->bufused <= iter->bufsize);
127
128	/*
129	 * A newly created iterator has an undefined position
130	 * until isc_interfaceiter_first() is called.
131	 */
132	iter->pos = (unsigned int) -1;
133	iter->result = ISC_R_FAILURE;
134
135	iter->magic = IFITER_MAGIC;
136	*iterp = iter;
137	return (ISC_R_SUCCESS);
138
139 failure:
140	if (iter->buf != NULL)
141		isc_mem_put(mctx, iter->buf, iter->bufsize);
142	isc_mem_put(mctx, iter, sizeof(*iter));
143	return (result);
144}
145
146/*
147 * Get information about the current interface to iter->current.
148 * If successful, return ISC_R_SUCCESS.
149 * If the interface has an unsupported address family,
150 * return ISC_R_IGNORE.  In case of other failure,
151 * return ISC_R_UNEXPECTED.
152 */
153
154static isc_result_t
155internal_current(isc_interfaceiter_t *iter) {
156	struct ifa_msghdr *ifam, *ifam_end;
157
158	REQUIRE(VALID_IFITER(iter));
159	REQUIRE (iter->pos < (unsigned int) iter->bufused);
160
161	ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
162	ifam_end = (struct ifa_msghdr *) ((char *) iter->buf + iter->bufused);
163
164	if (ifam->ifam_type == RTM_IFINFO) {
165		struct if_msghdr *ifm = (struct if_msghdr *) ifam;
166		struct sockaddr_dl *sdl = (struct sockaddr_dl *) (ifm + 1);
167		unsigned int namelen;
168
169		memset(&iter->current, 0, sizeof(iter->current));
170
171		namelen = sdl->sdl_nlen;
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, sdl->sdl_data, namelen);
177
178		iter->current.flags = 0;
179
180		if ((ifam->ifam_flags & IFF_UP) != 0)
181			iter->current.flags |= INTERFACE_F_UP;
182
183		if ((ifam->ifam_flags & IFF_POINTOPOINT) != 0)
184			iter->current.flags |= INTERFACE_F_POINTTOPOINT;
185
186		if ((ifam->ifam_flags & IFF_LOOPBACK) != 0)
187			iter->current.flags |= INTERFACE_F_LOOPBACK;
188
189		/*
190		 * This is not an interface address.
191		 * Force another iteration.
192		 */
193		return (ISC_R_IGNORE);
194	} else if (ifam->ifam_type == RTM_NEWADDR) {
195		int i;
196		int family;
197		struct sockaddr *mask_sa = NULL;
198		struct sockaddr *addr_sa = NULL;
199		struct sockaddr *dst_sa = NULL;
200
201		struct sockaddr *sa = (struct sockaddr *)(ifam + 1);
202		family = sa->sa_family;
203
204		for (i = 0; i < RTAX_MAX; i++)
205		{
206			if ((ifam->ifam_addrs & (1 << i)) == 0)
207				continue;
208
209			INSIST(sa < (struct sockaddr *) ifam_end);
210
211			switch (i) {
212			case RTAX_NETMASK: /* Netmask */
213				mask_sa = sa;
214				break;
215			case RTAX_IFA: /* Interface address */
216				addr_sa = sa;
217				break;
218			case RTAX_BRD: /* Broadcast or destination address */
219				dst_sa = sa;
220				break;
221			}
222#ifdef ISC_PLATFORM_HAVESALEN
223			sa = (struct sockaddr *)((char*)(sa)
224					 + ROUNDUP(sa->sa_len));
225#else
226#ifdef sgi
227			/*
228			 * Do as the contributed SGI code does.
229			 */
230			sa = (struct sockaddr *)((char*)(sa)
231					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
232#else
233			/* XXX untested. */
234			sa = (struct sockaddr *)((char*)(sa)
235					 + ROUNDUP(sizeof(struct sockaddr)));
236#endif
237#endif
238		}
239
240		if (addr_sa == NULL)
241			return (ISC_R_IGNORE);
242
243		family = addr_sa->sa_family;
244		if (family != AF_INET && family != AF_INET6)
245			return (ISC_R_IGNORE);
246
247		iter->current.af = family;
248
249		get_addr(family, &iter->current.address, addr_sa,
250			 iter->current.name);
251
252		if (mask_sa != NULL)
253			get_addr(family, &iter->current.netmask, mask_sa,
254				 iter->current.name);
255
256		if (dst_sa != NULL &&
257		    (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
258			get_addr(family, &iter->current.dstaddress, dst_sa,
259				 iter->current.name);
260
261		return (ISC_R_SUCCESS);
262	} else {
263		printf(isc_msgcat_get(isc_msgcat, ISC_MSGSET_IFITERSYSCTL,
264				      ISC_MSG_UNEXPECTEDTYPE,
265				      "warning: unexpected interface list "
266				      "message type\n"));
267		return (ISC_R_IGNORE);
268	}
269}
270
271/*
272 * Step the iterator to the next interface.  Unlike
273 * isc_interfaceiter_next(), this may leave the iterator
274 * positioned on an interface that will ultimately
275 * be ignored.  Return ISC_R_NOMORE if there are no more
276 * interfaces, otherwise ISC_R_SUCCESS.
277 */
278static isc_result_t
279internal_next(isc_interfaceiter_t *iter) {
280	struct ifa_msghdr *ifam;
281	REQUIRE (iter->pos < (unsigned int) iter->bufused);
282
283	ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
284
285	iter->pos += ifam->ifam_msglen;
286
287	if (iter->pos >= iter->bufused)
288		return (ISC_R_NOMORE);
289
290	return (ISC_R_SUCCESS);
291}
292
293static void
294internal_destroy(isc_interfaceiter_t *iter) {
295	UNUSED(iter); /* Unused. */
296	/*
297	 * Do nothing.
298	 */
299}
300
301static
302void internal_first(isc_interfaceiter_t *iter) {
303	iter->pos = 0;
304}
305