getifaddrs.c revision 1.11
1 /* $NetBSD: getifaddrs.c,v 1.11 2007/12/06 22:51:57 dyoung Exp $ */ 2 3 /* 4 * Copyright (c) 1995, 1999 5 * Berkeley Software Design, Inc. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp 26 */ 27 28 #include <sys/cdefs.h> 29 #if defined(LIBC_SCCS) && !defined(lint) 30 __RCSID("$NetBSD: getifaddrs.c,v 1.11 2007/12/06 22:51:57 dyoung Exp $"); 31 #endif /* LIBC_SCCS and not lint */ 32 33 #include "namespace.h" 34 #include <sys/types.h> 35 #include <sys/ioctl.h> 36 #include <sys/socket.h> 37 #include <net/if.h> 38 #include <sys/param.h> 39 #include <net/route.h> 40 #include <sys/sysctl.h> 41 #include <net/if_dl.h> 42 43 #include <assert.h> 44 #include <errno.h> 45 #include <ifaddrs.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #ifdef __weak_alias 50 __weak_alias(getifaddrs,_getifaddrs) 51 __weak_alias(freeifaddrs,_freeifaddrs) 52 #endif 53 54 #define SALIGN (sizeof(long) - 1) 55 #define SA_RLEN(sa) ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1)) 56 57 int 58 getifaddrs(struct ifaddrs **pif) 59 { 60 int icnt = 1; 61 int dcnt = 0; 62 int ncnt = 0; 63 int mib[6]; 64 size_t needed; 65 char *buf; 66 char *next; 67 struct ifaddrs *cif = 0; 68 char *p, *p0; 69 struct rt_msghdr *rtm; 70 struct if_msghdr *ifm; 71 struct ifa_msghdr *ifam; 72 struct sockaddr_dl *dl; 73 struct sockaddr *sa; 74 struct ifaddrs *ifa, *ift; 75 u_short idx = 0; 76 int i; 77 size_t len, alen; 78 char *data; 79 char *names; 80 81 _DIAGASSERT(pif != NULL); 82 83 mib[0] = CTL_NET; 84 mib[1] = PF_ROUTE; 85 mib[2] = 0; /* protocol */ 86 mib[3] = 0; /* wildcard address family */ 87 mib[4] = NET_RT_IFLIST; 88 mib[5] = 0; /* no flags */ 89 if (sysctl(mib, __arraycount(mib), NULL, &needed, NULL, 0) < 0) 90 return (-1); 91 if ((buf = malloc(needed)) == NULL) 92 return (-1); 93 if (sysctl(mib, __arraycount(mib), buf, &needed, NULL, 0) < 0) { 94 free(buf); 95 return (-1); 96 } 97 98 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) { 99 rtm = (struct rt_msghdr *)(void *)next; 100 if (rtm->rtm_version != RTM_VERSION) 101 continue; 102 switch (rtm->rtm_type) { 103 case RTM_IFINFO: 104 ifm = (struct if_msghdr *)(void *)rtm; 105 if (ifm->ifm_addrs & RTA_IFP) { 106 idx = ifm->ifm_index; 107 ++icnt; 108 dl = (struct sockaddr_dl *)(void *)(ifm + 1); 109 dcnt += SA_RLEN((struct sockaddr *)(void*)dl) + 110 ALIGNBYTES; 111 dcnt += sizeof(ifm->ifm_data); 112 ncnt += dl->sdl_nlen + 1; 113 } else 114 idx = 0; 115 break; 116 117 case RTM_NEWADDR: 118 ifam = (struct ifa_msghdr *)(void *)rtm; 119 if (idx && ifam->ifam_index != idx) 120 abort(); /* this cannot happen */ 121 122 #define RTA_MASKS (RTA_NETMASK | RTA_IFA | RTA_BRD) 123 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0) 124 break; 125 p = (char *)(void *)(ifam + 1); 126 ++icnt; 127 /* Scan to look for length of address */ 128 alen = 0; 129 for (p0 = p, i = 0; i < RTAX_MAX; i++) { 130 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i)) 131 == 0) 132 continue; 133 sa = (struct sockaddr *)(void *)p; 134 len = SA_RLEN(sa); 135 if (i == RTAX_IFA) { 136 alen = len; 137 break; 138 } 139 p += len; 140 } 141 for (p = p0, i = 0; i < RTAX_MAX; i++) { 142 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i)) 143 == 0) 144 continue; 145 sa = (struct sockaddr *)(void *)p; 146 len = SA_RLEN(sa); 147 if (i == RTAX_NETMASK && sa->sa_len == 0) 148 dcnt += alen; 149 else 150 dcnt += len; 151 p += len; 152 } 153 break; 154 } 155 } 156 157 if (icnt + dcnt + ncnt == 1) { 158 *pif = NULL; 159 free(buf); 160 return (0); 161 } 162 data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt); 163 if (data == NULL) { 164 free(buf); 165 return(-1); 166 } 167 168 ifa = (struct ifaddrs *)(void *)data; 169 data += sizeof(struct ifaddrs) * icnt; 170 names = data + dcnt; 171 172 memset(ifa, 0, sizeof(struct ifaddrs) * icnt); 173 ift = ifa; 174 175 idx = 0; 176 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) { 177 rtm = (struct rt_msghdr *)(void *)next; 178 if (rtm->rtm_version != RTM_VERSION) 179 continue; 180 switch (rtm->rtm_type) { 181 case RTM_IFINFO: 182 ifm = (struct if_msghdr *)(void *)rtm; 183 if (ifm->ifm_addrs & RTA_IFP) { 184 idx = ifm->ifm_index; 185 dl = (struct sockaddr_dl *)(void *)(ifm + 1); 186 187 cif = ift; 188 ift->ifa_name = names; 189 ift->ifa_flags = (int)ifm->ifm_flags; 190 memcpy(names, dl->sdl_data, 191 (size_t)dl->sdl_nlen); 192 names[dl->sdl_nlen] = 0; 193 names += dl->sdl_nlen + 1; 194 195 ift->ifa_addr = (struct sockaddr *)(void *)data; 196 memcpy(data, dl, (size_t)((struct sockaddr *) 197 (void *)dl)->sa_len); 198 data += SA_RLEN((struct sockaddr *)(void *)dl); 199 200 /* ifm_data needs to be aligned */ 201 ift->ifa_data = data = (void *)ALIGN(data); 202 memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data)); 203 data += sizeof(ifm->ifm_data); 204 205 ift = (ift->ifa_next = ift + 1); 206 } else 207 idx = 0; 208 break; 209 210 case RTM_NEWADDR: 211 ifam = (struct ifa_msghdr *)(void *)rtm; 212 if (idx && ifam->ifam_index != idx) 213 abort(); /* this cannot happen */ 214 215 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0) 216 break; 217 ift->ifa_name = cif->ifa_name; 218 ift->ifa_flags = cif->ifa_flags; 219 ift->ifa_data = NULL; 220 p = (char *)(void *)(ifam + 1); 221 /* Scan to look for length of address */ 222 alen = 0; 223 for (p0 = p, i = 0; i < RTAX_MAX; i++) { 224 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i)) 225 == 0) 226 continue; 227 sa = (struct sockaddr *)(void *)p; 228 len = SA_RLEN(sa); 229 if (i == RTAX_IFA) { 230 alen = len; 231 break; 232 } 233 p += len; 234 } 235 for (p = p0, i = 0; i < RTAX_MAX; i++) { 236 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i)) 237 == 0) 238 continue; 239 sa = (struct sockaddr *)(void *)p; 240 len = SA_RLEN(sa); 241 switch (i) { 242 case RTAX_IFA: 243 ift->ifa_addr = 244 (struct sockaddr *)(void *)data; 245 memcpy(data, p, len); 246 data += len; 247 break; 248 249 case RTAX_NETMASK: 250 ift->ifa_netmask = 251 (struct sockaddr *)(void *)data; 252 if (sa->sa_len == 0) { 253 memset(data, 0, alen); 254 data += alen; 255 break; 256 } 257 memcpy(data, p, len); 258 data += len; 259 break; 260 261 case RTAX_BRD: 262 ift->ifa_broadaddr = 263 (struct sockaddr *)(void *)data; 264 memcpy(data, p, len); 265 data += len; 266 break; 267 } 268 p += len; 269 } 270 271 272 ift = (ift->ifa_next = ift + 1); 273 break; 274 } 275 } 276 277 free(buf); 278 if (--ift >= ifa) { 279 ift->ifa_next = NULL; 280 *pif = ifa; 281 } else { 282 *pif = NULL; 283 free(ifa); 284 } 285 return (0); 286 } 287 288 void 289 freeifaddrs(struct ifaddrs *ifp) 290 { 291 292 _DIAGASSERT(ifp != NULL); 293 294 free(ifp); 295 } 296
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