1 /* $KAME: rtsold.c,v 1.31 2001/05/22 06:03:06 jinmei Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 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. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $FreeBSD: src/usr.sbin/rtsold/rtsold.c,v 1.1.2.4 2002/04/04 11:07:19 ume Exp $ 32 * $DragonFly: src/usr.sbin/rtsold/rtsold.c,v 1.5 2005/02/15 00:26:00 cpressey Exp $ 33 */ 34 35 #include <sys/types.h> 36 #include <sys/time.h> 37 #include <sys/socket.h> 38 39 #include <net/if.h> 40 #include <net/if_dl.h> 41 42 #include <netinet/in.h> 43 #include <netinet/icmp6.h> 44 45 #include <signal.h> 46 #include <unistd.h> 47 #include <syslog.h> 48 #include <string.h> 49 #include <stdlib.h> 50 #include <stdio.h> 51 #include <errno.h> 52 #include <err.h> 53 #include <stdarg.h> 54 #include <ifaddrs.h> 55 #include "rtsold.h" 56 57 struct ifinfo *iflist; 58 struct timeval tm_max = {0x7fffffff, 0x7fffffff}; 59 int aflag = 0; 60 int dflag = 0; 61 static int log_upto = 999; 62 static int fflag = 0; 63 64 /* protocol constatns */ 65 #define MAX_RTR_SOLICITATION_DELAY 1 /* second */ 66 #define RTR_SOLICITATION_INTERVAL 4 /* seconds */ 67 #define MAX_RTR_SOLICITATIONS 3 /* times */ 68 69 /* implementation dependent constants */ 70 #define PROBE_INTERVAL 60 /* secondes XXX: should be configurable */ 71 72 /* utility macros */ 73 /* a < b */ 74 #define TIMEVAL_LT(a, b) (((a).tv_sec < (b).tv_sec) ||\ 75 (((a).tv_sec == (b).tv_sec) && \ 76 ((a).tv_usec < (b).tv_usec))) 77 78 /* a <= b */ 79 #define TIMEVAL_LEQ(a, b) (((a).tv_sec < (b).tv_sec) ||\ 80 (((a).tv_sec == (b).tv_sec) &&\ 81 ((a).tv_usec <= (b).tv_usec))) 82 83 /* a == b */ 84 #define TIMEVAL_EQ(a, b) (((a).tv_sec==(b).tv_sec) && ((a).tv_usec==(b).tv_usec)) 85 86 int main(int argc, char *argv[]); 87 88 /* static variables and functions */ 89 static int mobile_node = 0; 90 static int do_dump; 91 /* 92 * XXX: the following two values should be configurable 93 */ 94 static const char *dumpfilename = "/var/run/rtsold.dump"; 95 static const char *pidfilename = "/var/run/rtsold.pid"; 96 97 static int ifconfig(char *ifname); 98 #if 0 99 static int ifreconfig(char *ifname); 100 #endif 101 static int make_packet(struct ifinfo *ifinfo); 102 static struct timeval *rtsol_check_timer(void); 103 static void TIMEVAL_ADD(struct timeval *a, struct timeval *b, 104 struct timeval *result); 105 static void TIMEVAL_SUB(struct timeval *a, struct timeval *b, 106 struct timeval *result); 107 108 static void rtsold_set_dump_file(int); 109 static void usage(char *progname); 110 static char **autoifprobe(void); 111 112 int 113 main(argc, argv) 114 int argc; 115 char *argv[]; 116 { 117 int s, rtsock, maxfd, ch; 118 int once = 0; 119 struct timeval *timeout; 120 struct fd_set fdset; 121 char *argv0; 122 const char *opts; 123 124 /* 125 * Initialization 126 */ 127 argv0 = argv[0]; 128 129 /* get option */ 130 if (argv0 && argv0[strlen(argv0) - 1] != 'd') { 131 fflag = 1; 132 once = 1; 133 opts = "adD"; 134 } else 135 opts = "adDfm1"; 136 137 while ((ch = getopt(argc, argv, opts)) != -1) { 138 switch (ch) { 139 case 'a': 140 aflag = 1; 141 break; 142 case 'd': 143 dflag = 1; 144 break; 145 case 'D': 146 dflag = 2; 147 break; 148 case 'f': 149 fflag = 1; 150 break; 151 case 'm': 152 mobile_node = 1; 153 break; 154 case '1': 155 once = 1; 156 break; 157 default: 158 usage(argv0); 159 /*NOTREACHED*/ 160 } 161 } 162 argc -= optind; 163 argv += optind; 164 165 if (aflag) { 166 int i; 167 168 if (argc != 0) { 169 usage(argv0); 170 /*NOTREACHED*/ 171 } 172 173 argv = autoifprobe(); 174 if (!argv) { 175 errx(1, "could not autoprobe interface"); 176 /*NOTREACHED*/ 177 } 178 179 for (i = 0; argv[i]; i++) 180 ; 181 argc = i; 182 } 183 if (argc == 0) { 184 usage(argv0); 185 /*NOTREACHED*/ 186 } 187 188 /* set log level */ 189 if (dflag == 0) 190 log_upto = LOG_NOTICE; 191 if (!fflag) { 192 char *ident; 193 ident = strrchr(argv0, '/'); 194 if (!ident) 195 ident = argv0; 196 else 197 ident++; 198 openlog(ident, LOG_NDELAY|LOG_PID, LOG_DAEMON); 199 if (log_upto >= 0) 200 setlogmask(LOG_UPTO(log_upto)); 201 } 202 203 #ifndef HAVE_ARC4RANDOM 204 /* random value initilization */ 205 srandom((u_long)time(NULL)); 206 #endif 207 208 /* warn if accept_rtadv is down */ 209 if (!getinet6sysctl(IPV6CTL_ACCEPT_RTADV)) 210 warnx("kernel is configured not to accept RAs"); 211 /* warn if forwarding is up */ 212 if (getinet6sysctl(IPV6CTL_FORWARDING)) 213 warnx("kernel is configured as a router, not a host"); 214 215 /* initialization to dump internal status to a file */ 216 if (signal(SIGUSR1, rtsold_set_dump_file) == SIG_ERR) { 217 errx(1, "failed to set signal for dump status"); 218 /*NOTREACHED*/ 219 } 220 221 /* 222 * Open a socket for sending RS and receiving RA. 223 * This should be done before calling ifinit(), since the function 224 * uses the socket. 225 */ 226 if ((s = sockopen()) < 0) { 227 errx(1, "failed to open a socket"); 228 /*NOTREACHED*/ 229 } 230 maxfd = s; 231 if ((rtsock = rtsock_open()) < 0) { 232 errx(1, "failed to open a socket"); 233 /*NOTREACHED*/ 234 } 235 if (rtsock > maxfd) 236 maxfd = rtsock; 237 238 /* configuration per interface */ 239 if (ifinit()) { 240 errx(1, "failed to initilizatoin interfaces"); 241 /*NOTREACHED*/ 242 } 243 while (argc--) { 244 if (ifconfig(*argv)) { 245 errx(1, "failed to initialize %s", *argv); 246 /*NOTREACHED*/ 247 } 248 argv++; 249 } 250 251 /* setup for probing default routers */ 252 if (probe_init()) { 253 errx(1, "failed to setup for probing routers"); 254 /*NOTREACHED*/ 255 } 256 257 if (!fflag) 258 daemon(0, 0); /* act as a daemon */ 259 260 /* dump the current pid */ 261 if (!once) { 262 pid_t pid = getpid(); 263 FILE *fp; 264 265 if ((fp = fopen(pidfilename, "w")) == NULL) 266 warnmsg(LOG_ERR, __FUNCTION__, 267 "failed to open a log file(%s): %s", 268 pidfilename, strerror(errno)); 269 else { 270 fprintf(fp, "%d\n", pid); 271 fclose(fp); 272 } 273 } 274 275 FD_ZERO(&fdset); 276 FD_SET(s, &fdset); 277 FD_SET(rtsock, &fdset); 278 while (1) { /* main loop */ 279 int e; 280 struct fd_set select_fd = fdset; 281 282 if (do_dump) { /* SIGUSR1 */ 283 do_dump = 0; 284 rtsold_dump_file(dumpfilename); 285 } 286 287 timeout = rtsol_check_timer(); 288 289 if (once) { 290 struct ifinfo *ifi; 291 292 /* if we have no timeout, we are done (or failed) */ 293 if (timeout == NULL) 294 break; 295 296 /* if all interfaces have got RA packet, we are done */ 297 for (ifi = iflist; ifi; ifi = ifi->next) { 298 if (ifi->state != IFS_DOWN && ifi->racnt == 0) 299 break; 300 } 301 if (ifi == NULL) 302 break; 303 } 304 e = select(maxfd + 1, &select_fd, NULL, NULL, timeout); 305 if (e < 1) { 306 if (e < 0 && errno != EINTR) { 307 warnmsg(LOG_ERR, __FUNCTION__, "select: %s", 308 strerror(errno)); 309 } 310 continue; 311 } 312 313 /* packet reception */ 314 if (FD_ISSET(rtsock, &select_fd)) 315 rtsock_input(rtsock); 316 if (FD_ISSET(s, &select_fd)) 317 rtsol_input(s); 318 } 319 /* NOTREACHED */ 320 321 return 0; 322 } 323 324 static int 325 ifconfig(char *ifname) 326 { 327 struct ifinfo *ifinfo; 328 struct sockaddr_dl *sdl; 329 int flags; 330 331 if ((sdl = if_nametosdl(ifname)) == NULL) { 332 warnmsg(LOG_ERR, __FUNCTION__, 333 "failed to get link layer information for %s", ifname); 334 return(-1); 335 } 336 if (find_ifinfo(sdl->sdl_index)) { 337 warnmsg(LOG_ERR, __FUNCTION__, 338 "interface %s was already configured", ifname); 339 free(sdl); 340 return(-1); 341 } 342 343 if ((ifinfo = malloc(sizeof(*ifinfo))) == NULL) { 344 warnmsg(LOG_ERR, __FUNCTION__, "memory allocation failed"); 345 free(sdl); 346 return(-1); 347 } 348 memset(ifinfo, 0, sizeof(*ifinfo)); 349 ifinfo->sdl = sdl; 350 351 strncpy(ifinfo->ifname, ifname, sizeof(ifinfo->ifname)); 352 353 /* construct a router solicitation message */ 354 if (make_packet(ifinfo)) 355 goto bad; 356 357 /* 358 * check if the interface is available. 359 * also check if SIOCGIFMEDIA ioctl is OK on the interface. 360 */ 361 ifinfo->mediareqok = 1; 362 ifinfo->active = interface_status(ifinfo); 363 if (!ifinfo->mediareqok) { 364 /* 365 * probe routers periodically even if the link status 366 * does not change. 367 */ 368 ifinfo->probeinterval = PROBE_INTERVAL; 369 } 370 371 /* activate interface: interface_up returns 0 on success */ 372 flags = interface_up(ifinfo->ifname); 373 if (flags == 0) 374 ifinfo->state = IFS_DELAY; 375 else if (flags == IFS_TENTATIVE) 376 ifinfo->state = IFS_TENTATIVE; 377 else 378 ifinfo->state = IFS_DOWN; 379 380 rtsol_timer_update(ifinfo); 381 382 /* link into chain */ 383 if (iflist) 384 ifinfo->next = iflist; 385 iflist = ifinfo; 386 387 return(0); 388 389 bad: 390 free(ifinfo->sdl); 391 free(ifinfo); 392 return(-1); 393 } 394 395 #if 0 396 static int 397 ifreconfig(char *ifname) 398 { 399 struct ifinfo *ifi, *prev; 400 int rv; 401 402 prev = NULL; 403 for (ifi = iflist; ifi; ifi = ifi->next) { 404 if (strncmp(ifi->ifname, ifname, sizeof(ifi->ifname)) == 0) 405 break; 406 prev = ifi; 407 } 408 prev->next = ifi->next; 409 410 rv = ifconfig(ifname); 411 412 /* reclaim it after ifconfig() in case ifname is pointer inside ifi */ 413 if (ifi->rs_data) 414 free(ifi->rs_data); 415 free(ifi->sdl); 416 free(ifi); 417 418 return rv; 419 } 420 #endif 421 422 struct ifinfo * 423 find_ifinfo(int ifindex) 424 { 425 struct ifinfo *ifi; 426 427 for (ifi = iflist; ifi; ifi = ifi->next) 428 if (ifi->sdl->sdl_index == ifindex) 429 return(ifi); 430 431 return(NULL); 432 } 433 434 static int 435 make_packet(struct ifinfo *ifinfo) 436 { 437 char *buf; 438 struct nd_router_solicit *rs; 439 size_t packlen = sizeof(struct nd_router_solicit), lladdroptlen = 0; 440 441 if ((lladdroptlen = lladdropt_length(ifinfo->sdl)) == 0) { 442 warnmsg(LOG_INFO, __FUNCTION__, 443 "link-layer address option has null length" 444 " on %s. Treat as not included.", ifinfo->ifname); 445 } 446 packlen += lladdroptlen; 447 ifinfo->rs_datalen = packlen; 448 449 /* allocate buffer */ 450 if ((buf = malloc(packlen)) == NULL) { 451 warnmsg(LOG_ERR, __FUNCTION__, 452 "memory allocation failed for %s", ifinfo->ifname); 453 return(-1); 454 } 455 ifinfo->rs_data = buf; 456 457 /* fill in the message */ 458 rs = (struct nd_router_solicit *)buf; 459 rs->nd_rs_type = ND_ROUTER_SOLICIT; 460 rs->nd_rs_code = 0; 461 rs->nd_rs_cksum = 0; 462 rs->nd_rs_reserved = 0; 463 buf += sizeof(*rs); 464 465 /* fill in source link-layer address option */ 466 if (lladdroptlen) 467 lladdropt_fill(ifinfo->sdl, (struct nd_opt_hdr *)buf); 468 469 return(0); 470 } 471 472 static struct timeval * 473 rtsol_check_timer() 474 { 475 static struct timeval returnval; 476 struct timeval now, rtsol_timer; 477 struct ifinfo *ifinfo; 478 int flags; 479 480 gettimeofday(&now, NULL); 481 482 rtsol_timer = tm_max; 483 484 for (ifinfo = iflist; ifinfo; ifinfo = ifinfo->next) { 485 if (TIMEVAL_LEQ(ifinfo->expire, now)) { 486 if (dflag > 1) 487 warnmsg(LOG_DEBUG, __FUNCTION__, 488 "timer expiration on %s, " 489 "state = %d", ifinfo->ifname, 490 ifinfo->state); 491 492 switch (ifinfo->state) { 493 case IFS_DOWN: 494 case IFS_TENTATIVE: 495 /* interface_up returns 0 on success */ 496 flags = interface_up(ifinfo->ifname); 497 if (flags == 0) 498 ifinfo->state = IFS_DELAY; 499 else if (flags == IFS_TENTATIVE) 500 ifinfo->state = IFS_TENTATIVE; 501 else 502 ifinfo->state = IFS_DOWN; 503 break; 504 case IFS_IDLE: 505 { 506 int oldstatus = ifinfo->active; 507 int probe = 0; 508 509 ifinfo->active = 510 interface_status(ifinfo); 511 512 if (oldstatus != ifinfo->active) { 513 warnmsg(LOG_DEBUG, __FUNCTION__, 514 "%s status is changed" 515 " from %d to %d", 516 ifinfo->ifname, 517 oldstatus, ifinfo->active); 518 probe = 1; 519 ifinfo->state = IFS_DELAY; 520 } 521 else if (ifinfo->probeinterval && 522 (ifinfo->probetimer -= 523 ifinfo->timer.tv_sec) <= 0) { 524 /* probe timer expired */ 525 ifinfo->probetimer = 526 ifinfo->probeinterval; 527 probe = 1; 528 ifinfo->state = IFS_PROBE; 529 } 530 531 if (probe && mobile_node) 532 defrouter_probe(ifinfo->sdl->sdl_index); 533 break; 534 } 535 case IFS_DELAY: 536 ifinfo->state = IFS_PROBE; 537 sendpacket(ifinfo); 538 break; 539 case IFS_PROBE: 540 if (ifinfo->probes < MAX_RTR_SOLICITATIONS) 541 sendpacket(ifinfo); 542 else { 543 warnmsg(LOG_INFO, __FUNCTION__, 544 "No answer " 545 "after sending %d RSs", 546 ifinfo->probes); 547 ifinfo->probes = 0; 548 ifinfo->state = IFS_IDLE; 549 } 550 break; 551 } 552 rtsol_timer_update(ifinfo); 553 } 554 555 if (TIMEVAL_LT(ifinfo->expire, rtsol_timer)) 556 rtsol_timer = ifinfo->expire; 557 } 558 559 if (TIMEVAL_EQ(rtsol_timer, tm_max)) { 560 warnmsg(LOG_DEBUG, __FUNCTION__, "there is no timer"); 561 return(NULL); 562 } 563 else if (TIMEVAL_LT(rtsol_timer, now)) 564 /* this may occur when the interval is too small */ 565 returnval.tv_sec = returnval.tv_usec = 0; 566 else 567 TIMEVAL_SUB(&rtsol_timer, &now, &returnval); 568 569 if (dflag > 1) 570 warnmsg(LOG_DEBUG, __FUNCTION__, "New timer is %ld:%08ld", 571 (long)returnval.tv_sec, (long)returnval.tv_usec); 572 573 return(&returnval); 574 } 575 576 void 577 rtsol_timer_update(struct ifinfo *ifinfo) 578 { 579 #define MILLION 1000000 580 #define DADRETRY 10 /* XXX: adhoc */ 581 long interval; 582 struct timeval now; 583 584 bzero(&ifinfo->timer, sizeof(ifinfo->timer)); 585 586 switch (ifinfo->state) { 587 case IFS_DOWN: 588 case IFS_TENTATIVE: 589 if (++ifinfo->dadcount > DADRETRY) { 590 ifinfo->dadcount = 0; 591 ifinfo->timer.tv_sec = PROBE_INTERVAL; 592 } 593 else 594 ifinfo->timer.tv_sec = 1; 595 break; 596 case IFS_IDLE: 597 if (mobile_node) { 598 /* XXX should be configurable */ 599 ifinfo->timer.tv_sec = 3; 600 } 601 else 602 ifinfo->timer = tm_max; /* stop timer(valid?) */ 603 break; 604 case IFS_DELAY: 605 #ifndef HAVE_ARC4RANDOM 606 interval = random() % (MAX_RTR_SOLICITATION_DELAY * MILLION); 607 #else 608 interval = arc4random() % (MAX_RTR_SOLICITATION_DELAY * MILLION); 609 #endif 610 ifinfo->timer.tv_sec = interval / MILLION; 611 ifinfo->timer.tv_usec = interval % MILLION; 612 break; 613 case IFS_PROBE: 614 if (ifinfo->probes < MAX_RTR_SOLICITATIONS) 615 ifinfo->timer.tv_sec = RTR_SOLICITATION_INTERVAL; 616 else { 617 /* 618 * After sending MAX_RTR_SOLICITATIONS solicitations, 619 * we're just waiting for possible replies; there 620 * will be no more solicatation. Thus, we change 621 * the timer value to MAX_RTR_SOLICITATION_DELAY based 622 * on RFC 2461, Section 6.3.7. 623 */ 624 ifinfo->timer.tv_sec = MAX_RTR_SOLICITATION_DELAY; 625 } 626 break; 627 default: 628 warnmsg(LOG_ERR, __FUNCTION__, 629 "illegal interface state(%d) on %s", 630 ifinfo->state, ifinfo->ifname); 631 return; 632 } 633 634 /* reset the timer */ 635 if (TIMEVAL_EQ(ifinfo->timer, tm_max)) { 636 ifinfo->expire = tm_max; 637 warnmsg(LOG_DEBUG, __FUNCTION__, 638 "stop timer for %s", ifinfo->ifname); 639 } 640 else { 641 gettimeofday(&now, NULL); 642 TIMEVAL_ADD(&now, &ifinfo->timer, &ifinfo->expire); 643 644 if (dflag > 1) 645 warnmsg(LOG_DEBUG, __FUNCTION__, 646 "set timer for %s to %d:%d", ifinfo->ifname, 647 (int)ifinfo->timer.tv_sec, 648 (int)ifinfo->timer.tv_usec); 649 } 650 651 #undef MILLION 652 } 653 654 /* timer related utility functions */ 655 #define MILLION 1000000 656 657 /* result = a + b */ 658 static void 659 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result) 660 { 661 long l; 662 663 if ((l = a->tv_usec + b->tv_usec) < MILLION) { 664 result->tv_usec = l; 665 result->tv_sec = a->tv_sec + b->tv_sec; 666 } 667 else { 668 result->tv_usec = l - MILLION; 669 result->tv_sec = a->tv_sec + b->tv_sec + 1; 670 } 671 } 672 673 /* 674 * result = a - b 675 * XXX: this function assumes that a >= b. 676 */ 677 void 678 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result) 679 { 680 long l; 681 682 if ((l = a->tv_usec - b->tv_usec) >= 0) { 683 result->tv_usec = l; 684 result->tv_sec = a->tv_sec - b->tv_sec; 685 } 686 else { 687 result->tv_usec = MILLION + l; 688 result->tv_sec = a->tv_sec - b->tv_sec - 1; 689 } 690 } 691 692 static void 693 rtsold_set_dump_file(int signo __unused) 694 { 695 do_dump = 1; 696 } 697 698 static void 699 usage(char *progname) 700 { 701 if (progname && progname[strlen(progname) - 1] != 'd') { 702 fprintf(stderr, "usage: rtsol [-dD] interfaces...\n"); 703 fprintf(stderr, "usage: rtsol [-dD] -a\n"); 704 } else { 705 fprintf(stderr, "usage: rtsold [-adDfm1] interfaces...\n"); 706 fprintf(stderr, "usage: rtsold [-dDfm1] -a\n"); 707 } 708 exit(1); 709 } 710 711 void 712 #if __STDC__ 713 warnmsg(int priority, const char *func, const char *msg, ...) 714 #else 715 warnmsg(priority, func, msg, va_alist) 716 int priority; 717 const char *func; 718 const char *msg; 719 va_dcl 720 #endif 721 { 722 va_list ap; 723 char buf[BUFSIZ]; 724 725 va_start(ap, msg); 726 if (fflag) { 727 if (priority <= log_upto) { 728 vfprintf(stderr, msg, ap); 729 fprintf(stderr, "\n"); 730 } 731 } else { 732 snprintf(buf, sizeof(buf), "<%s> %s", func, msg); 733 msg = buf; 734 vsyslog(priority, msg, ap); 735 } 736 va_end(ap); 737 } 738 739 static char ** 740 autoifprobe() 741 { 742 #ifndef HAVE_GETIFADDRS 743 errx(1, "-a is not available with the configuration"); 744 #else 745 static char ifname[IFNAMSIZ + 1]; 746 static char *argv[2]; 747 struct ifaddrs *ifap, *ifa, *target; 748 749 if (getifaddrs(&ifap) != 0) 750 return NULL; 751 752 target = NULL; 753 /* find an ethernet */ 754 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 755 if ((ifa->ifa_flags & IFF_UP) == 0) 756 continue; 757 if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0) 758 continue; 759 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) 760 continue; 761 if ((ifa->ifa_flags & IFF_MULTICAST) == 0) 762 continue; 763 764 if (ifa->ifa_addr->sa_family != AF_INET6) 765 continue; 766 767 if (target && strcmp(target->ifa_name, ifa->ifa_name) == 0) 768 continue; 769 770 if (!target) 771 target = ifa; 772 else { 773 /* if we find multiple candidates, failure. */ 774 if (dflag > 1) 775 warnx("multiple interfaces found"); 776 target = NULL; 777 break; 778 } 779 } 780 781 if (target) { 782 strncpy(ifname, target->ifa_name, sizeof(ifname) - 1); 783 ifname[sizeof(ifname) - 1] = '\0'; 784 argv[0] = ifname; 785 argv[1] = NULL; 786 787 if (dflag > 0) 788 warnx("probing %s", argv[0]); 789 } 790 freeifaddrs(ifap); 791 if (target) 792 return argv; 793 else 794 return (char **)NULL; 795 #endif 796 } 797