ip/iptunnel.c

   1 /*
   2  * iptunnel.c          "ip tunnel"
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <unistd.h>
  17 #include <sys/types.h>
  18 #include <sys/socket.h>
  19 #include <arpa/inet.h>
  20 #include <sys/ioctl.h>
  21 #include <net/if.h>
  22 #include <net/if_arp.h>
  23 #include <linux/ip.h>
  24 #include <linux/if_tunnel.h>
  25
  26 #include "rt_names.h"
  27 #include "utils.h"
  28 #include "ip_common.h"
  29 #include "tunnel.h"
  30
  31 static void usage(void) __attribute__((noreturn));
  32
  33 static void usage(void)
  34 {
  35         fprintf(stderr, "Usage: ip tunnel { add | change | del | show | prl | 6rd } [ NAME ]\n");
  36         fprintf(stderr, "          [ mode { ipip | gre | sit | isatap | vti } ] [ remote ADDR ] [ local ADDR ]\n");
  37         fprintf(stderr, "          [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ]\n");
  38         fprintf(stderr, "          [ prl-default ADDR ] [ prl-nodefault ADDR ] [ prl-delete ADDR ]\n");
  39         fprintf(stderr, "          [ 6rd-prefix ADDR ] [ 6rd-relay_prefix ADDR ] [ 6rd-reset ]\n");
  40         fprintf(stderr, "          [ ttl TTL ] [ tos TOS ] [ [no]pmtudisc ] [ dev PHYS_DEV ]\n");
  41         fprintf(stderr, "\n");
  42         fprintf(stderr, "Where: NAME := STRING\n");
  43         fprintf(stderr, "       ADDR := { IP_ADDRESS | any }\n");
  44         fprintf(stderr, "       TOS  := { STRING | 00..ff | inherit | inherit/STRING | inherit/00..ff }\n");
  45         fprintf(stderr, "       TTL  := { 1..255 | inherit }\n");
  46         fprintf(stderr, "       KEY  := { DOTTED_QUAD | NUMBER }\n");
  47         exit(-1);
  48 }
  49
  50 static void set_tunnel_proto(struct ip_tunnel_parm *p, int proto)
  51 {
  52         if (p->iph.protocol && p->iph.protocol != proto) {
  53                 fprintf(stderr,
  54                         "You managed to ask for more than one tunnel mode.\n");
  55                 exit(-1);
  56         }
  57         p->iph.protocol = proto;
  58 }
  59
  60 static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
  61 {
  62         int count = 0;
  63         const char *medium = NULL;
  64         int isatap = 0;
  65
  66         memset(p, 0, sizeof(*p));
  67         p->iph.version = 4;
  68         p->iph.ihl = 5;
  69 #ifndef IP_DF
  70 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  71 #endif
  72         p->iph.frag_off = htons(IP_DF);
  73
  74         while (argc > 0) {
  75                 if (strcmp(*argv, "mode") == 0) {
  76                         NEXT_ARG();
  77                         if (strcmp(*argv, "ipip") == 0 ||
  78                             strcmp(*argv, "ip/ip") == 0) {
  79                                 set_tunnel_proto(p, IPPROTO_IPIP);
  80                         } else if (strcmp(*argv, "gre") == 0 ||
  81                                    strcmp(*argv, "gre/ip") == 0) {
  82                                 set_tunnel_proto(p, IPPROTO_GRE);
  83                         } else if (strcmp(*argv, "sit") == 0 ||
  84                                    strcmp(*argv, "ipv6/ip") == 0) {
  85                                 set_tunnel_proto(p, IPPROTO_IPV6);
  86                         } else if (strcmp(*argv, "isatap") == 0) {
  87                                 set_tunnel_proto(p, IPPROTO_IPV6);
  88                                 isatap++;
  89                         } else if (strcmp(*argv, "vti") == 0) {
  90                                 set_tunnel_proto(p, IPPROTO_IPIP);
  91                                 p->i_flags |= VTI_ISVTI;
  92                         } else {
  93                                 fprintf(stderr,
  94                                         "Unknown tunnel mode \"%s\"\n", *argv);
  95                                 exit(-1);
  96                         }
  97                 } else if (strcmp(*argv, "key") == 0) {
  98                         NEXT_ARG();
  99                         p->i_flags |= GRE_KEY;
 100                         p->o_flags |= GRE_KEY;
 101                         p->i_key = p->o_key = tnl_parse_key("key", *argv);
 102                 } else if (strcmp(*argv, "ikey") == 0) {
 103                         NEXT_ARG();
 104                         p->i_flags |= GRE_KEY;
 105                         p->i_key = tnl_parse_key("ikey", *argv);
 106                 } else if (strcmp(*argv, "okey") == 0) {
 107                         NEXT_ARG();
 108                         p->o_flags |= GRE_KEY;
 109                         p->o_key = tnl_parse_key("okey", *argv);
 110                 } else if (strcmp(*argv, "seq") == 0) {
 111                         p->i_flags |= GRE_SEQ;
 112                         p->o_flags |= GRE_SEQ;
 113                 } else if (strcmp(*argv, "iseq") == 0) {
 114                         p->i_flags |= GRE_SEQ;
 115                 } else if (strcmp(*argv, "oseq") == 0) {
 116                         p->o_flags |= GRE_SEQ;
 117                 } else if (strcmp(*argv, "csum") == 0) {
 118                         p->i_flags |= GRE_CSUM;
 119                         p->o_flags |= GRE_CSUM;
 120                 } else if (strcmp(*argv, "icsum") == 0) {
 121                         p->i_flags |= GRE_CSUM;
 122                 } else if (strcmp(*argv, "ocsum") == 0) {
 123                         p->o_flags |= GRE_CSUM;
 124                 } else if (strcmp(*argv, "nopmtudisc") == 0) {
 125                         p->iph.frag_off = 0;
 126                 } else if (strcmp(*argv, "pmtudisc") == 0) {
 127                         p->iph.frag_off = htons(IP_DF);
 128                 } else if (strcmp(*argv, "remote") == 0) {
 129                         NEXT_ARG();
 130                         p->iph.daddr = get_addr32(*argv);
 131                 } else if (strcmp(*argv, "local") == 0) {
 132                         NEXT_ARG();
 133                         p->iph.saddr = get_addr32(*argv);
 134                 } else if (strcmp(*argv, "dev") == 0) {
 135                         NEXT_ARG();
 136                         medium = *argv;
 137                 } else if (strcmp(*argv, "ttl") == 0 ||
 138                            strcmp(*argv, "hoplimit") == 0 ||
 139                            strcmp(*argv, "hlim") == 0) {
 140                         __u8 uval;
 141
 142                         NEXT_ARG();
 143                         if (strcmp(*argv, "inherit") != 0) {
 144                                 if (get_u8(&uval, *argv, 0))
 145                                         invarg("invalid TTL\n", *argv);
 146                                 p->iph.ttl = uval;
 147                         }
 148                 } else if (strcmp(*argv, "tos") == 0 ||
 149                            strcmp(*argv, "tclass") == 0 ||
 150                            matches(*argv, "dsfield") == 0) {
 151                         char *dsfield;
 152                         __u32 uval;
 153
 154                         NEXT_ARG();
 155                         dsfield = *argv;
 156                         strsep(&dsfield, "/");
 157                         if (strcmp(*argv, "inherit") != 0) {
 158                                 dsfield = *argv;
 159                                 p->iph.tos = 0;
 160                         } else
 161                                 p->iph.tos = 1;
 162                         if (dsfield) {
 163                                 if (rtnl_dsfield_a2n(&uval, dsfield))
 164                                         invarg("bad TOS value", *argv);
 165                                 p->iph.tos |= uval;
 166                         }
 167                 } else {
 168                         if (strcmp(*argv, "name") == 0)
 169                                 NEXT_ARG();
 170                         else if (matches(*argv, "help") == 0)
 171                                 usage();
 172
 173                         if (p->name[0])
 174                                 duparg2("name", *argv);
 175                         if (get_ifname(p->name, *argv))
 176                                 invarg("\"name\" not a valid ifname", *argv);
 177                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 178                                 struct ip_tunnel_parm old_p = {};
 179
 180                                 if (tnl_get_ioctl(*argv, &old_p))
 181                                         return -1;
 182                                 *p = old_p;
 183                         }
 184                 }
 185                 count++;
 186                 argc--; argv++;
 187         }
 188
 189
 190         if (p->iph.protocol == 0) {
 191                 if (memcmp(p->name, "gre", 3) == 0)
 192                         p->iph.protocol = IPPROTO_GRE;
 193                 else if (memcmp(p->name, "ipip", 4) == 0)
 194                         p->iph.protocol = IPPROTO_IPIP;
 195                 else if (memcmp(p->name, "sit", 3) == 0)
 196                         p->iph.protocol = IPPROTO_IPV6;
 197                 else if (memcmp(p->name, "isatap", 6) == 0) {
 198                         p->iph.protocol = IPPROTO_IPV6;
 199                         isatap++;
 200                 } else if (memcmp(p->name, "vti", 3) == 0) {
 201                         p->iph.protocol = IPPROTO_IPIP;
 202                         p->i_flags |= VTI_ISVTI;
 203                 }
 204         }
 205
 206         if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 207                 if (!(p->i_flags & VTI_ISVTI) &&
 208                     (p->iph.protocol != IPPROTO_GRE)) {
 209                         fprintf(stderr, "Keys are not allowed with ipip and sit tunnels\n");
 210                         return -1;
 211                 }
 212         }
 213
 214         if (medium) {
 215                 p->link = ll_name_to_index(medium);
 216                 if (p->link == 0) {
 217                         fprintf(stderr, "Cannot find device \"%s\"\n", medium);
 218                         return -1;
 219                 }
 220         }
 221
 222         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 223                 p->i_key = p->iph.daddr;
 224                 p->i_flags |= GRE_KEY;
 225         }
 226         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 227                 p->o_key = p->iph.daddr;
 228                 p->o_flags |= GRE_KEY;
 229         }
 230         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 231                 fprintf(stderr, "A broadcast tunnel requires a source address\n");
 232                 return -1;
 233         }
 234         if (isatap)
 235                 p->i_flags |= SIT_ISATAP;
 236
 237         return 0;
 238 }
 239
 240 static const char *tnl_defname(const struct ip_tunnel_parm *p)
 241 {
 242         switch (p->iph.protocol) {
 243         case IPPROTO_IPIP:
 244                 if (p->i_flags & VTI_ISVTI)
 245                         return "ip_vti0";
 246                 else
 247                         return "tunl0";
 248         case IPPROTO_GRE:
 249                 return "gre0";
 250         case IPPROTO_IPV6:
 251                 return "sit0";
 252         }
 253         return NULL;
 254 }
 255
 256 static int do_add(int cmd, int argc, char **argv)
 257 {
 258         struct ip_tunnel_parm p;
 259         const char *basedev;
 260
 261         if (parse_args(argc, argv, cmd, &p) < 0)
 262                 return -1;
 263
 264         if (p.iph.ttl && p.iph.frag_off == 0) {
 265                 fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
 266                 return -1;
 267         }
 268
 269         basedev = tnl_defname(&p);
 270         if (!basedev) {
 271                 fprintf(stderr,
 272                         "cannot determine tunnel mode (ipip, gre, vti or sit)\n");
 273                 return -1;
 274         }
 275
 276         return tnl_add_ioctl(cmd, basedev, p.name, &p);
 277 }
 278
 279 static int do_del(int argc, char **argv)
 280 {
 281         struct ip_tunnel_parm p;
 282
 283         if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)
 284                 return -1;
 285
 286         return tnl_del_ioctl(tnl_defname(&p) ? : p.name, p.name, &p);
 287 }
 288
 289 static void print_tunnel(struct ip_tunnel_parm *p)
 290 {
 291         struct ip_tunnel_6rd ip6rd = {};
 292         char s1[1024];
 293         char s2[1024];
 294
 295         /* Do not use format_host() for local addr,
 296          * symbolic name will not be useful.
 297          */
 298         printf("%s: %s/ip remote %s local %s",
 299                p->name,
 300                tnl_strproto(p->iph.protocol),
 301                p->iph.daddr ? format_host_r(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1)) : "any",
 302                p->iph.saddr ? rt_addr_n2a_r(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2)) : "any");
 303
 304         if (p->iph.protocol == IPPROTO_IPV6 && (p->i_flags & SIT_ISATAP)) {
 305                 struct ip_tunnel_prl prl[16] = {};
 306                 int i;
 307
 308                 prl[0].datalen = sizeof(prl) - sizeof(prl[0]);
 309                 prl[0].addr = htonl(INADDR_ANY);
 310
 311                 if (!tnl_prl_ioctl(SIOCGETPRL, p->name, prl))
 312                         for (i = 1; i < ARRAY_SIZE(prl); i++) {
 313                                 if (prl[i].addr != htonl(INADDR_ANY)) {
 314                                         printf(" %s %s ",
 315                                                (prl[i].flags & PRL_DEFAULT) ? "pdr" : "pr",
 316                                                format_host(AF_INET, 4, &prl[i].addr));
 317                                 }
 318                         }
 319         }
 320
 321         if (p->link) {
 322                 const char *n = ll_index_to_name(p->link);
 323
 324                 if (n)
 325                         printf(" dev %s", n);
 326         }
 327
 328         if (p->iph.ttl)
 329                 printf(" ttl %u", p->iph.ttl);
 330         else
 331                 printf(" ttl inherit");
 332
 333         if (p->iph.tos) {
 334                 SPRINT_BUF(b1);
 335                 printf(" tos");
 336                 if (p->iph.tos & 1)
 337                         printf(" inherit");
 338                 if (p->iph.tos & ~1)
 339                         printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
 340                                rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
 341         }
 342
 343         if (!(p->iph.frag_off & htons(IP_DF)))
 344                 printf(" nopmtudisc");
 345
 346         if (p->iph.protocol == IPPROTO_IPV6 && !tnl_ioctl_get_6rd(p->name, &ip6rd) && ip6rd.prefixlen) {
 347                 printf(" 6rd-prefix %s/%u",
 348                        inet_ntop(AF_INET6, &ip6rd.prefix, s1, sizeof(s1)),
 349                        ip6rd.prefixlen);
 350                 if (ip6rd.relay_prefix) {
 351                         printf(" 6rd-relay_prefix %s/%u",
 352                                format_host(AF_INET, 4, &ip6rd.relay_prefix),
 353                                ip6rd.relay_prefixlen);
 354                 }
 355         }
 356
 357         if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
 358                 printf(" key %u", ntohl(p->i_key));
 359         else if ((p->i_flags | p->o_flags) & GRE_KEY) {
 360                 if (p->i_flags & GRE_KEY)
 361                         printf(" ikey %u", ntohl(p->i_key));
 362                 if (p->o_flags & GRE_KEY)
 363                         printf(" okey %u", ntohl(p->o_key));
 364         }
 365
 366         if (p->i_flags & GRE_SEQ)
 367                 printf("%s  Drop packets out of sequence.", _SL_);
 368         if (p->i_flags & GRE_CSUM)
 369                 printf("%s  Checksum in received packet is required.", _SL_);
 370         if (p->o_flags & GRE_SEQ)
 371                 printf("%s  Sequence packets on output.", _SL_);
 372         if (p->o_flags & GRE_CSUM)
 373                 printf("%s  Checksum output packets.", _SL_);
 374 }
 375
 376 /*
 377  * @p1: user specified parameter
 378  * @p2: database entry
 379  */
 380 static int ip_tunnel_parm_match(const struct ip_tunnel_parm *p1,
 381                                 const struct ip_tunnel_parm *p2)
 382 {
 383         return ((!p1->link || p1->link == p2->link) &&
 384                 (!p1->name[0] || strcmp(p1->name, p2->name) == 0) &&
 385                 (!p1->iph.daddr || p1->iph.daddr == p2->iph.daddr) &&
 386                 (!p1->iph.saddr || p1->iph.saddr == p2->iph.saddr) &&
 387                 (!p1->i_key || p1->i_key == p2->i_key));
 388 }
 389
 390 static int do_tunnels_list(struct ip_tunnel_parm *p)
 391 {
 392         char buf[512];
 393         int err = -1;
 394         FILE *fp = fopen("/proc/net/dev", "r");
 395
 396         if (fp == NULL) {
 397                 perror("fopen");
 398                 return -1;
 399         }
 400
 401         /* skip two lines at the begenning of the file */
 402         if (!fgets(buf, sizeof(buf), fp) ||
 403             !fgets(buf, sizeof(buf), fp)) {
 404                 fprintf(stderr, "/proc/net/dev read error\n");
 405                 goto end;
 406         }
 407
 408         while (fgets(buf, sizeof(buf), fp) != NULL) {
 409                 char name[IFNAMSIZ];
 410                 int index, type;
 411                 struct ip_tunnel_parm p1;
 412                 char *ptr;
 413
 414                 buf[sizeof(buf) - 1] = '\0';
 415                 ptr = strchr(buf, ':');
 416                 if (ptr == NULL ||
 417                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 418                         fprintf(stderr, "Wrong format for /proc/net/dev. Giving up.\n");
 419                         goto end;
 420                 }
 421                 if (p->name[0] && strcmp(p->name, name))
 422                         continue;
 423                 index = ll_name_to_index(name);
 424                 if (index == 0)
 425                         continue;
 426                 type = ll_index_to_type(index);
 427                 if (type == -1) {
 428                         fprintf(stderr, "Failed to get type of \"%s\"\n", name);
 429                         continue;
 430                 }
 431                 switch (type) {
 432                 case ARPHRD_TUNNEL:
 433                 case ARPHRD_IPGRE:
 434                 case ARPHRD_SIT:
 435                         break;
 436                 default:
 437                         continue;
 438                 }
 439                 memset(&p1, 0, sizeof(p1));
 440                 if (tnl_get_ioctl(name, &p1))
 441                         continue;
 442                 if (!ip_tunnel_parm_match(p, &p1))
 443                         continue;
 444                 print_tunnel(&p1);
 445                 if (show_stats) {
 446                         struct rtnl_link_stats64 s;
 447
 448                         if (!tnl_get_stats(ptr, &s))
 449                                 tnl_print_stats(&s);
 450                 }
 451                 fputc('\n', stdout);
 452         }
 453         err = 0;
 454  end:
 455         fclose(fp);
 456         return err;
 457 }
 458
 459 static int do_show(int argc, char **argv)
 460 {
 461         struct ip_tunnel_parm p;
 462         const char *basedev;
 463
 464         ll_init_map(&rth);
 465         if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)
 466                 return -1;
 467
 468         basedev = tnl_defname(&p);
 469         if (!basedev)
 470                 return do_tunnels_list(&p);
 471
 472         if (tnl_get_ioctl(p.name[0] ? p.name : basedev, &p))
 473                 return -1;
 474
 475         print_tunnel(&p);
 476         fputc('\n', stdout);
 477         return 0;
 478 }
 479
 480 static int do_prl(int argc, char **argv)
 481 {
 482         struct ip_tunnel_prl p = {};
 483         int count = 0;
 484         int cmd = 0;
 485         const char *medium = NULL;
 486
 487         while (argc > 0) {
 488                 if (strcmp(*argv, "prl-default") == 0) {
 489                         NEXT_ARG();
 490                         cmd = SIOCADDPRL;
 491                         p.addr = get_addr32(*argv);
 492                         p.flags |= PRL_DEFAULT;
 493                         count++;
 494                 } else if (strcmp(*argv, "prl-nodefault") == 0) {
 495                         NEXT_ARG();
 496                         cmd = SIOCADDPRL;
 497                         p.addr = get_addr32(*argv);
 498                         count++;
 499                 } else if (strcmp(*argv, "prl-delete") == 0) {
 500                         NEXT_ARG();
 501                         cmd = SIOCDELPRL;
 502                         p.addr = get_addr32(*argv);
 503                         count++;
 504                 } else if (strcmp(*argv, "dev") == 0) {
 505                         NEXT_ARG();
 506                         if (check_ifname(*argv))
 507                                 invarg("\"dev\" not a valid ifname", *argv);
 508                         medium = *argv;
 509                 } else {
 510                         fprintf(stderr,
 511                                 "Invalid PRL parameter \"%s\"\n", *argv);
 512                         exit(-1);
 513                 }
 514                 if (count > 1) {
 515                         fprintf(stderr,
 516                                 "One PRL entry at a time\n");
 517                         exit(-1);
 518                 }
 519                 argc--; argv++;
 520         }
 521         if (!medium) {
 522                 fprintf(stderr, "Must specify device\n");
 523                 exit(-1);
 524         }
 525
 526         return tnl_prl_ioctl(cmd, medium, &p);
 527 }
 528
 529 static int do_6rd(int argc, char **argv)
 530 {
 531         struct ip_tunnel_6rd ip6rd = {};
 532         int cmd = 0;
 533         const char *medium = NULL;
 534         inet_prefix prefix;
 535
 536         while (argc > 0) {
 537                 if (strcmp(*argv, "6rd-prefix") == 0) {
 538                         NEXT_ARG();
 539                         if (get_prefix(&prefix, *argv, AF_INET6))
 540                                 invarg("invalid 6rd_prefix\n", *argv);
 541                         cmd = SIOCADD6RD;
 542                         memcpy(&ip6rd.prefix, prefix.data, 16);
 543                         ip6rd.prefixlen = prefix.bitlen;
 544                 } else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
 545                         NEXT_ARG();
 546                         if (get_prefix(&prefix, *argv, AF_INET))
 547                                 invarg("invalid 6rd-relay_prefix\n", *argv);
 548                         cmd = SIOCADD6RD;
 549                         memcpy(&ip6rd.relay_prefix, prefix.data, 4);
 550                         ip6rd.relay_prefixlen = prefix.bitlen;
 551                 } else if (strcmp(*argv, "6rd-reset") == 0) {
 552                         cmd = SIOCDEL6RD;
 553                 } else if (strcmp(*argv, "dev") == 0) {
 554                         NEXT_ARG();
 555                         if (check_ifname(*argv))
 556                                 invarg("\"dev\" not a valid ifname", *argv);
 557                         medium = *argv;
 558                 } else {
 559                         fprintf(stderr,
 560                                 "Invalid 6RD parameter \"%s\"\n", *argv);
 561                         exit(-1);
 562                 }
 563                 argc--; argv++;
 564         }
 565         if (!medium) {
 566                 fprintf(stderr, "Must specify device\n");
 567                 exit(-1);
 568         }
 569
 570         return tnl_6rd_ioctl(cmd, medium, &ip6rd);
 571 }
 572
 573 static int tunnel_mode_is_ipv6(char *tunnel_mode)
 574 {
 575         static const char * const ipv6_modes[] = {
 576                 "ipv6/ipv6", "ip6ip6",
 577                 "vti6",
 578                 "ip/ipv6", "ipv4/ipv6", "ipip6", "ip4ip6",
 579                 "ip6gre", "gre/ipv6",
 580                 "any/ipv6", "any"
 581         };
 582         int i;
 583
 584         for (i = 0; i < ARRAY_SIZE(ipv6_modes); i++) {
 585                 if (strcmp(ipv6_modes[i], tunnel_mode) == 0)
 586                         return 1;
 587         }
 588         return 0;
 589 }
 590
 591 int do_iptunnel(int argc, char **argv)
 592 {
 593         int i;
 594
 595         for (i = 0; i < argc - 1; i++) {
 596                 if (strcmp(argv[i], "mode") == 0) {
 597                         if (tunnel_mode_is_ipv6(argv[i + 1]))
 598                                 preferred_family = AF_INET6;
 599                         break;
 600                 }
 601         }
 602         switch (preferred_family) {
 603         case AF_UNSPEC:
 604                 preferred_family = AF_INET;
 605                 break;
 606         case AF_INET:
 607                 break;
 608         /*
 609          * This is silly enough but we have no easy way to make it
 610          * protocol-independent because of unarranged structure between
 611          * IPv4 and IPv6.
 612          */
 613         case AF_INET6:
 614                 return do_ip6tunnel(argc, argv);
 615         default:
 616                 fprintf(stderr, "Unsupported protocol family: %d\n", preferred_family);
 617                 exit(-1);
 618         }
 619
 620         if (argc > 0) {
 621                 if (matches(*argv, "add") == 0)
 622                         return do_add(SIOCADDTUNNEL, argc - 1, argv + 1);
 623                 if (matches(*argv, "change") == 0)
 624                         return do_add(SIOCCHGTUNNEL, argc - 1, argv + 1);
 625                 if (matches(*argv, "delete") == 0)
 626                         return do_del(argc - 1, argv + 1);
 627                 if (matches(*argv, "show") == 0 ||
 628                     matches(*argv, "lst") == 0 ||
 629                     matches(*argv, "list") == 0)
 630                         return do_show(argc - 1, argv + 1);
 631                 if (matches(*argv, "prl") == 0)
 632                         return do_prl(argc - 1, argv + 1);
 633                 if (matches(*argv, "6rd") == 0)
 634                         return do_6rd(argc - 1, argv + 1);
 635                 if (matches(*argv, "help") == 0)
 636                         usage();
 637         } else
 638                 return do_show(0, NULL);
 639
 640         fprintf(stderr, "Command \"%s\" is unknown, try \"ip tunnel help\"\n", *argv);
 641         exit(-1);
 642 }