ifwatchd.c revision 1.3
1 /* $NetBSD: ifwatchd.c,v 1.3 2001/12/10 14:54:09 martin Exp $ */ 2 3 /* 4 * Copyright (c) 2001 Martin Husemann <martin (at) duskware.de> 5 * 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 * 2. The name of the author may not be used to endorse or promote products 13 * derived from this software withough specific prior written permission 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/types.h> 28 #include <sys/param.h> 29 #include <sys/ioctl.h> 30 #include <sys/socket.h> 31 #include <sys/queue.h> 32 #include <net/if.h> 33 #include <net/if_dl.h> 34 #include <net/route.h> 35 #include <netinet/in.h> 36 #include <arpa/inet.h> 37 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 #include <netdb.h> 43 #include <err.h> 44 #include <ifaddrs.h> 45 46 /* local functions */ 47 static void usage(void); 48 static void dispatch(void*, size_t); 49 static void check_addrs(char *cp, int addrs, int is_up); 50 static void invoke_script(struct sockaddr *sa, int is_up, int ifindex); 51 static void list_interfaces(const char *ifnames); 52 static void rescan_interfaces(void); 53 static void free_interfaces(void); 54 static int find_interface(int index); 55 static void run_initial_ups(void); 56 57 /* stolen from /sbin/route */ 58 #define ROUNDUP(a) \ 59 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 60 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) 61 62 /* global variables */ 63 static int verbose = 0; 64 static int inhibit_initial = 0; 65 static const char *up_script = NULL; 66 static const char *down_script = NULL; 67 68 struct interface_data { 69 SLIST_ENTRY(interface_data) next; 70 int index; 71 char * ifname; 72 }; 73 SLIST_HEAD(,interface_data) ifs = SLIST_HEAD_INITIALIZER(ifs); 74 75 int 76 main(int argc, char **argv) 77 { 78 int c, s, n; 79 int errs = 0; 80 char msg[2048], *msgp; 81 82 while ((c = getopt(argc, argv, "vhiu:d:")) != -1) 83 switch (c) { 84 case 'h': 85 usage(); 86 return 0; 87 case 'i': 88 inhibit_initial = 1; 89 break; 90 case 'v': 91 verbose++; 92 break; 93 94 case 'u': 95 up_script = optarg; 96 break; 97 98 case 'd': 99 down_script = optarg; 100 break; 101 102 default: 103 errs++; 104 break; 105 } 106 107 if (errs) 108 usage(); 109 110 argv += optind; 111 argc -= optind; 112 113 if (argc <= 0) 114 usage(); 115 116 if (verbose) { 117 printf("up_script: %s\ndown_script: %s\n", 118 up_script, down_script); 119 printf("verbosity = %d\n", verbose); 120 } 121 122 while (argc > 0) { 123 list_interfaces(argv[0]); 124 argv++; argc--; 125 } 126 127 if (!verbose) 128 daemon(0,0); 129 130 if (!inhibit_initial) 131 run_initial_ups(); 132 133 s = socket(PF_ROUTE, SOCK_RAW, 0); 134 if (s < 0) { 135 perror("open routing socket"); 136 exit(1); 137 } 138 139 for (;;) { 140 n = read(s, msg, sizeof msg); 141 msgp = msg; 142 for (msgp = msg; n > 0; n -= ((struct rt_msghdr*)msgp)->rtm_msglen, msgp += ((struct rt_msghdr*)msgp)->rtm_msglen) { 143 dispatch(msgp, n); 144 145 } 146 } 147 148 close(s); 149 free_interfaces(); 150 151 exit(0); 152 } 153 154 static void 155 usage() 156 { 157 fprintf(stderr, 158 "usage:\n" 159 "\tifwatchd [-h] [-v] [-u up-script] [-d down-script] ifname(s)\n" 160 "\twhere:\n" 161 "\t -h show this help message\n" 162 "\t -v verbose/debug output, don't run in background\n" 163 "\t -i no (!) initial run of the up script if the interface\n" 164 "\t is already up on ifwatchd startup\n" 165 "\t -u <cmd> specify command to run on interface up event\n" 166 "\t -d <cmd> specify command to run on interface down event\n"); 167 exit(1); 168 } 169 170 static void 171 dispatch(void *msg, size_t len) 172 { 173 struct rt_msghdr *hd = msg; 174 struct ifa_msghdr *ifam; 175 int is_up; 176 177 is_up = 0; 178 switch (hd->rtm_type) { 179 case RTM_NEWADDR: 180 is_up = 1; 181 goto work; 182 case RTM_DELADDR: 183 is_up = 0; 184 goto work; 185 case RTM_IFANNOUNCE: 186 rescan_interfaces(); 187 break; 188 } 189 if (verbose) 190 printf("unknown message ignored\n"); 191 return; 192 193 work: 194 ifam = (struct ifa_msghdr *)msg; 195 check_addrs((char *)(ifam + 1), ifam->ifam_addrs, is_up); 196 } 197 198 static void 199 check_addrs(cp, addrs, is_up) 200 char *cp; 201 int addrs, is_up; 202 { 203 struct sockaddr *sa; 204 int ifndx = 0, i; 205 206 if (addrs == 0) 207 return; 208 for (i = 1; i; i <<= 1) { 209 if (i & addrs) { 210 sa = (struct sockaddr *)cp; 211 if (i == RTA_IFP) { 212 struct sockaddr_dl * li = (struct sockaddr_dl*)sa; 213 ifndx = li->sdl_index; 214 if (!find_interface(ifndx)) { 215 if (verbose) 216 printf("ignoring change on interface #%d\n", ifndx); 217 return; 218 } 219 } else if (i == RTA_IFA) { 220 invoke_script(sa, is_up, ifndx); 221 } 222 ADVANCE(cp, sa); 223 } 224 } 225 } 226 227 static void 228 invoke_script(sa, is_up, ifindex) 229 struct sockaddr *sa; 230 int is_up, ifindex; 231 { 232 char addr[NI_MAXHOST], ifname_buf[IFNAMSIZ], *ifname, *cmd; 233 const char *script; 234 235 ifname = if_indextoname(ifindex, ifname_buf); 236 if (sa->sa_len == 0) { 237 fprintf(stderr, "illegal socket address (sa_len == 0)\n"); 238 return; 239 } 240 241 if (getnameinfo(sa, sa->sa_len, addr, sizeof addr, NULL, 0, NI_NUMERICHOST)) { 242 if (verbose) 243 printf("getnameinfo failed\n"); 244 return; /* this address can not be handled */ 245 } 246 247 script = is_up? up_script : down_script; 248 if (script == NULL) return; 249 250 asprintf(&cmd, "%s \"%s\" %s \"%s\"", script, ifname, 251 is_up?"up":"down", addr); 252 if (cmd == NULL) { 253 fprintf(stderr, "out of memory\n"); 254 return; 255 } 256 if (verbose) 257 printf("calling: %s\n", cmd); 258 system(cmd); 259 free(cmd); 260 } 261 262 static void list_interfaces(const char *ifnames) 263 { 264 char * names = strdup(ifnames); 265 char * name, *lasts; 266 static const char sep[] = " \t"; 267 struct interface_data * p; 268 269 for (name = strtok_r(names, sep, &lasts); name != NULL; name = strtok_r(NULL, sep, &lasts)) { 270 p = malloc(sizeof(*p)); 271 SLIST_INSERT_HEAD(&ifs, p, next); 272 p->ifname = strdup(name); 273 p->index = if_nametoindex(p->ifname); 274 if (verbose) 275 printf("interface \"%s\" has index %d\n", p->ifname, p->index); 276 } 277 free(names); 278 } 279 280 static void rescan_interfaces() 281 { 282 struct interface_data * p; 283 284 SLIST_FOREACH(p, &ifs, next) { 285 p->index = if_nametoindex(p->ifname); 286 if (verbose) 287 printf("interface \"%s\" has index %d\n", p->ifname, p->index); 288 } 289 } 290 291 static void free_interfaces() 292 { 293 struct interface_data * p; 294 295 while (!SLIST_EMPTY(&ifs)) { 296 p = SLIST_FIRST(&ifs); 297 SLIST_REMOVE_HEAD(&ifs, next); 298 free(p->ifname); 299 free(p); 300 } 301 } 302 303 static int find_interface(index) 304 int index; 305 { 306 struct interface_data * p; 307 308 SLIST_FOREACH(p, &ifs, next) 309 if (p->index == index) 310 return 1; 311 return 0; 312 } 313 314 static void run_initial_ups() 315 { 316 struct interface_data * ifd; 317 struct ifaddrs *res = NULL, *p; 318 319 if (getifaddrs(&res) == 0) { 320 for (p = res; p; p = p->ifa_next) { 321 if ((p->ifa_flags & IFF_UP) == 0) 322 continue; 323 if (p->ifa_addr == NULL) 324 continue; 325 if (p->ifa_addr->sa_family == AF_LINK) 326 continue; 327 SLIST_FOREACH(ifd, &ifs, next) { 328 if (strcmp(ifd->ifname, p->ifa_name) == 0) { 329 invoke_script(p->ifa_addr, 1, ifd->index); 330 break; 331 } 332 } 333 } 334 freeifaddrs(res); 335 } 336 } 337
Indexes created Thu Sep 25 16:09:42 GMT 2025