1 /*
2  * Copyright (C) 2004, 2005, 2007, 2008  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: interfaceiter.c,v 1.45 2008/12/01 03:51:47 marka Exp $ */
19 
20 /*! \file */
21 
22 #include <config.h>
23 
24 #include <sys/types.h>
25 #include <sys/ioctl.h>
26 #ifdef HAVE_SYS_SOCKIO_H
27 #include <sys/sockio.h>		/* Required for ifiter_ioctl.c. */
28 #endif
29 
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <unistd.h>
33 #include <errno.h>
34 
35 #include <isc/interfaceiter.h>
36 #include <isc/log.h>
37 #include <isc/magic.h>
38 #include <isc/mem.h>
39 #include <isc/msgs.h>
40 #include <isc/net.h>
41 #include <isc/print.h>
42 #include <isc/result.h>
43 #include <isc/strerror.h>
44 #include <isc/string.h>
45 #include <isc/types.h>
46 #include <isc/util.h>
47 
48 /* Must follow <isc/net.h>. */
49 #ifdef HAVE_NET_IF6_H
50 #include <net/if6.h>
51 #endif
52 #include <net/if.h>
53 
54 #ifdef HAVE_LINUX_IF_ADDR_H
55 # include <linux/if_addr.h>
56 #endif
57 
58 /* Common utility functions */
59 
60 /*%
61  * Extract the network address part from a "struct sockaddr".
62  * \brief
63  * The address family is given explicitly
64  * instead of using src->sa_family, because the latter does not work
65  * for copying a network mask obtained by SIOCGIFNETMASK (it does
66  * not have a valid address family).
67  */
68 
69 static void
70 get_addr(unsigned int family, isc_netaddr_t *dst, struct sockaddr *src,
71 	 char *ifname)
72 {
73 	struct sockaddr_in6 *sa6;
74 
75 #if !defined(ISC_PLATFORM_HAVEIFNAMETOINDEX) || \
76     !defined(ISC_PLATFORM_HAVESCOPEID)
77 	UNUSED(ifname);
78 #endif
79 
80 	/* clear any remaining value for safety */
81 	memset(dst, 0, sizeof(*dst));
82 
83 	dst->family = family;
84 	switch (family) {
85 	case AF_INET:
86 		memcpy(&dst->type.in,
87 		       &((struct sockaddr_in *)(void *)src)->sin_addr,
88 		       sizeof(struct in_addr));
89 		break;
90 	case AF_INET6:
91 		sa6 = (struct sockaddr_in6 *)(void *)src;
92 		memcpy(&dst->type.in6, &sa6->sin6_addr,
93 		       sizeof(struct in6_addr));
94 #ifdef ISC_PLATFORM_HAVESCOPEID
95 		if (sa6->sin6_scope_id != 0)
96 			isc_netaddr_setzone(dst, sa6->sin6_scope_id);
97 		else {
98 			/*
99 			 * BSD variants embed scope zone IDs in the 128bit
100 			 * address as a kernel internal form.  Unfortunately,
101 			 * the embedded IDs are not hidden from applications
102 			 * when getting access to them by sysctl or ioctl.
103 			 * We convert the internal format to the pure address
104 			 * part and the zone ID part.
105 			 * Since multicast addresses should not appear here
106 			 * and they cannot be distinguished from netmasks,
107 			 * we only consider unicast link-local addresses.
108 			 */
109 			if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) {
110 				isc_uint16_t zone16;
111 
112 				memcpy(&zone16, &sa6->sin6_addr.s6_addr[2],
113 				       sizeof(zone16));
114 				zone16 = ntohs(zone16);
115 				if (zone16 != 0) {
116 					/* the zone ID is embedded */
117 					isc_netaddr_setzone(dst,
118 							    (isc_uint32_t)zone16);
119 					dst->type.in6.s6_addr[2] = 0;
120 					dst->type.in6.s6_addr[3] = 0;
121 #ifdef ISC_PLATFORM_HAVEIFNAMETOINDEX
122 				} else if (ifname != NULL) {
123 					unsigned int zone;
124 
125 					/*
126 					 * sin6_scope_id is still not provided,
127 					 * but the corresponding interface name
128 					 * is know.  Use the interface ID as
129 					 * the link ID.
130 					 */
131 					zone = if_nametoindex(ifname);
132 					if (zone != 0) {
133 						isc_netaddr_setzone(dst,
134 								    (isc_uint32_t)zone);
135 					}
136 #endif
137 				}
138 			}
139 		}
140 #endif
141 		break;
142 	default:
143 		INSIST(0);
144 		break;
145 	}
146 }
147 
148 /*
149  * Include system-dependent code.
150  */
151 
152 #ifdef __linux
153 #define ISC_IF_INET6_SZ \
154     sizeof("00000000000000000000000000000001 01 80 10 80 XXXXXXloXXXXXXXX\n")
155 static isc_result_t linux_if_inet6_next(isc_interfaceiter_t *);
156 static isc_result_t linux_if_inet6_current(isc_interfaceiter_t *);
157 static void linux_if_inet6_first(isc_interfaceiter_t *iter);
158 #endif
159 
160 #if HAVE_GETIFADDRS
161 #include "ifiter_getifaddrs.c"
162 #elif HAVE_IFLIST_SYSCTL
163 #include "ifiter_sysctl.c"
164 #else
165 #include "ifiter_ioctl.c"
166 #endif
167 
168 #ifdef __linux
169 static void
170 linux_if_inet6_first(isc_interfaceiter_t *iter) {
171 	if (iter->proc != NULL) {
172 		rewind(iter->proc);
173 		(void)linux_if_inet6_next(iter);
174 	} else
175 		iter->valid = ISC_R_NOMORE;
176 }
177 
178 static isc_result_t
179 linux_if_inet6_next(isc_interfaceiter_t *iter) {
180 	if (iter->proc != NULL &&
181 	    fgets(iter->entry, sizeof(iter->entry), iter->proc) != NULL)
182 		iter->valid = ISC_R_SUCCESS;
183 	else
184 		iter->valid = ISC_R_NOMORE;
185 	return (iter->valid);
186 }
187 
188 static isc_result_t
189 linux_if_inet6_current(isc_interfaceiter_t *iter) {
190 	char address[33];
191 	char name[IF_NAMESIZE+1];
192 	struct in6_addr addr6;
193 	unsigned int ifindex;
194 	int prefix, scope, flags;
195 	int res;
196 	unsigned int i;
197 
198 	if (iter->valid != ISC_R_SUCCESS)
199 		return (iter->valid);
200 	if (iter->proc == NULL) {
201 		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
202 			      ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
203 			      "/proc/net/if_inet6:iter->proc == NULL");
204 		return (ISC_R_FAILURE);
205 	}
206 
207 	res = sscanf(iter->entry, "%32[a-f0-9] %x %x %x %x %16s\n",
208 		     address, &ifindex, &prefix, &scope, &flags, name);
209 	if (res != 6) {
210 		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
211 			      ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
212 			      "/proc/net/if_inet6:sscanf() -> %d (expected 6)",
213 			      res);
214 		return (ISC_R_FAILURE);
215 	}
216 	if (strlen(address) != 32) {
217 		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
218 			      ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
219 			      "/proc/net/if_inet6:strlen(%s) != 32", address);
220 		return (ISC_R_FAILURE);
221 	}
222 	/*
223 	** Ignore DAD addresses --
224 	** we can't bind to them until they are resolved
225 	*/
226 #ifdef IFA_F_TENTATIVE
227 	if (flags & IFA_F_TENTATIVE)
228 		return (ISC_R_IGNORE);
229 #endif
230 
231 	for (i = 0; i < 16; i++) {
232 		unsigned char byte;
233 		static const char hex[] = "0123456789abcdef";
234 		byte = ((strchr(hex, address[i * 2]) - hex) << 4) |
235 		       (strchr(hex, address[i * 2 + 1]) - hex);
236 		addr6.s6_addr[i] = byte;
237 	}
238 	iter->current.af = AF_INET6;
239 	iter->current.flags = INTERFACE_F_UP;
240 	isc_netaddr_fromin6(&iter->current.address, &addr6);
241 	iter->current.ifindex = ifindex;
242 	if (isc_netaddr_islinklocal(&iter->current.address)) {
243 		isc_netaddr_setzone(&iter->current.address,
244 				    (isc_uint32_t)ifindex);
245 	}
246 	for (i = 0; i < 16; i++) {
247 		if (prefix > 8) {
248 			addr6.s6_addr[i] = 0xff;
249 			prefix -= 8;
250 		} else {
251 			addr6.s6_addr[i] = (0xff << (8 - prefix)) & 0xff;
252 			prefix = 0;
253 		}
254 	}
255 	isc_netaddr_fromin6(&iter->current.netmask, &addr6);
256 	strncpy(iter->current.name, name, sizeof(iter->current.name));
257 	return (ISC_R_SUCCESS);
258 }
259 #endif
260 
261 /*
262  * The remaining code is common to the sysctl and ioctl case.
263  */
264 
265 isc_result_t
266 isc_interfaceiter_current(isc_interfaceiter_t *iter,
267 			  isc_interface_t *ifdata)
268 {
269 	REQUIRE(iter->result == ISC_R_SUCCESS);
270 	memcpy(ifdata, &iter->current, sizeof(*ifdata));
271 	return (ISC_R_SUCCESS);
272 }
273 
274 isc_result_t
275 isc_interfaceiter_first(isc_interfaceiter_t *iter) {
276 	isc_result_t result;
277 
278 	REQUIRE(VALID_IFITER(iter));
279 
280 	internal_first(iter);
281 	for (;;) {
282 		result = internal_current(iter);
283 		if (result != ISC_R_IGNORE)
284 			break;
285 		result = internal_next(iter);
286 		if (result != ISC_R_SUCCESS)
287 			break;
288 	}
289 	iter->result = result;
290 	return (result);
291 }
292 
293 isc_result_t
294 isc_interfaceiter_next(isc_interfaceiter_t *iter) {
295 	isc_result_t result;
296 
297 	REQUIRE(VALID_IFITER(iter));
298 	REQUIRE(iter->result == ISC_R_SUCCESS);
299 
300 	for (;;) {
301 		result = internal_next(iter);
302 		if (result != ISC_R_SUCCESS)
303 			break;
304 		result = internal_current(iter);
305 		if (result != ISC_R_IGNORE)
306 			break;
307 	}
308 	iter->result = result;
309 	return (result);
310 }
311 
312 void
313 isc_interfaceiter_destroy(isc_interfaceiter_t **iterp)
314 {
315 	isc_interfaceiter_t *iter;
316 	REQUIRE(iterp != NULL);
317 	iter = *iterp;
318 	REQUIRE(VALID_IFITER(iter));
319 
320 	internal_destroy(iter);
321 	if (iter->buf != NULL)
322 		isc_mem_put(iter->mctx, iter->buf, iter->bufsize);
323 
324 	iter->magic = 0;
325 	isc_mem_put(iter->mctx, iter, sizeof(*iter));
326 	*iterp = NULL;
327 }
328