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         char medium[IFNAMSIZ] = {};
  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                         if (strcmp(*argv, "any"))
 131                                 p->iph.daddr = get_addr32(*argv);
 132                         else
 133                                 p->iph.daddr = htonl(INADDR_ANY);
 134                 } else if (strcmp(*argv, "local") == 0) {
 135                         NEXT_ARG();
 136                         if (strcmp(*argv, "any"))
 137                                 p->iph.saddr = get_addr32(*argv);
 138                         else
 139                                 p->iph.saddr = htonl(INADDR_ANY);
 140                 } else if (strcmp(*argv, "dev") == 0) {
 141                         NEXT_ARG();
 142                         strncpy(medium, *argv, IFNAMSIZ - 1);
 143                 } else if (strcmp(*argv, "ttl") == 0 ||
 144                            strcmp(*argv, "hoplimit") == 0 ||
 145                            strcmp(*argv, "hlim") == 0) {
 146                         __u8 uval;
 147
 148                         NEXT_ARG();
 149                         if (strcmp(*argv, "inherit") != 0) {
 150                                 if (get_u8(&uval, *argv, 0))
 151                                         invarg("invalid TTL\n", *argv);
 152                                 p->iph.ttl = uval;
 153                         }
 154                 } else if (strcmp(*argv, "tos") == 0 ||
 155                            strcmp(*argv, "tclass") == 0 ||
 156                            matches(*argv, "dsfield") == 0) {
 157                         char *dsfield;
 158                         __u32 uval;
 159
 160                         NEXT_ARG();
 161                         dsfield = *argv;
 162                         strsep(&dsfield, "/");
 163                         if (strcmp(*argv, "inherit") != 0) {
 164                                 dsfield = *argv;
 165                                 p->iph.tos = 0;
 166                         } else
 167                                 p->iph.tos = 1;
 168                         if (dsfield) {
 169                                 if (rtnl_dsfield_a2n(&uval, dsfield))
 170                                         invarg("bad TOS value", *argv);
 171                                 p->iph.tos |= uval;
 172                         }
 173                 } else {
 174                         if (strcmp(*argv, "name") == 0)
 175                                 NEXT_ARG();
 176                         else if (matches(*argv, "help") == 0)
 177                                 usage();
 178
 179                         if (p->name[0])
 180                                 duparg2("name", *argv);
 181                         strncpy(p->name, *argv, IFNAMSIZ - 1);
 182                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 183                                 struct ip_tunnel_parm old_p = {};
 184
 185                                 if (tnl_get_ioctl(*argv, &old_p))
 186                                         return -1;
 187                                 *p = old_p;
 188                         }
 189                 }
 190                 count++;
 191                 argc--; argv++;
 192         }
 193
 194
 195         if (p->iph.protocol == 0) {
 196                 if (memcmp(p->name, "gre", 3) == 0)
 197                         p->iph.protocol = IPPROTO_GRE;
 198                 else if (memcmp(p->name, "ipip", 4) == 0)
 199                         p->iph.protocol = IPPROTO_IPIP;
 200                 else if (memcmp(p->name, "sit", 3) == 0)
 201                         p->iph.protocol = IPPROTO_IPV6;
 202                 else if (memcmp(p->name, "isatap", 6) == 0) {
 203                         p->iph.protocol = IPPROTO_IPV6;
 204                         isatap++;
 205                 } else if (memcmp(p->name, "vti", 3) == 0) {
 206                         p->iph.protocol = IPPROTO_IPIP;
 207                         p->i_flags |= VTI_ISVTI;
 208                 }
 209         }
 210
 211         if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 212                 if (!(p->i_flags & VTI_ISVTI) &&
 213                     (p->iph.protocol != IPPROTO_GRE)) {
 214                         fprintf(stderr, "Keys are not allowed with ipip and sit tunnels\n");
 215                         return -1;
 216                 }
 217         }
 218
 219         if (medium[0]) {
 220                 p->link = ll_name_to_index(medium);
 221                 if (p->link == 0) {
 222                         fprintf(stderr, "Cannot find device \"%s\"\n", medium);
 223                         return -1;
 224                 }
 225         }
 226
 227         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 228                 p->i_key = p->iph.daddr;
 229                 p->i_flags |= GRE_KEY;
 230         }
 231         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 232                 p->o_key = p->iph.daddr;
 233                 p->o_flags |= GRE_KEY;
 234         }
 235         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 236                 fprintf(stderr, "A broadcast tunnel requires a source address\n");
 237                 return -1;
 238         }
 239         if (isatap)
 240                 p->i_flags |= SIT_ISATAP;
 241
 242         return 0;
 243 }
 244
 245 static const char *tnl_defname(const struct ip_tunnel_parm *p)
 246 {
 247         switch (p->iph.protocol) {
 248         case IPPROTO_IPIP:
 249                 if (p->i_flags & VTI_ISVTI)
 250                         return "ip_vti0";
 251                 else
 252                         return "tunl0";
 253         case IPPROTO_GRE:
 254                 return "gre0";
 255         case IPPROTO_IPV6:
 256                 return "sit0";
 257         }
 258         return NULL;
 259 }
 260
 261 static int do_add(int cmd, int argc, char **argv)
 262 {
 263         struct ip_tunnel_parm p;
 264         const char *basedev;
 265
 266         if (parse_args(argc, argv, cmd, &p) < 0)
 267                 return -1;
 268
 269         if (p.iph.ttl && p.iph.frag_off == 0) {
 270                 fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
 271                 return -1;
 272         }
 273
 274         basedev = tnl_defname(&p);
 275         if (!basedev) {
 276                 fprintf(stderr,
 277                         "cannot determine tunnel mode (ipip, gre, vti or sit)\n");
 278                 return -1;
 279         }
 280
 281         return tnl_add_ioctl(cmd, basedev, p.name, &p);
 282 }
 283
 284 static int do_del(int argc, char **argv)
 285 {
 286         struct ip_tunnel_parm p;
 287
 288         if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)
 289                 return -1;
 290
 291         return tnl_del_ioctl(tnl_defname(&p) ? : p.name, p.name, &p);
 292 }
 293
 294 static void print_tunnel(struct ip_tunnel_parm *p)
 295 {
 296         struct ip_tunnel_6rd ip6rd = {};
 297         char s1[1024];
 298         char s2[1024];
 299
 300         /* Do not use format_host() for local addr,
 301          * symbolic name will not be useful.
 302          */
 303         printf("%s: %s/ip remote %s local %s",
 304                p->name,
 305                tnl_strproto(p->iph.protocol),
 306                p->iph.daddr ? format_host_r(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1)) : "any",
 307                p->iph.saddr ? rt_addr_n2a_r(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2)) : "any");
 308
 309         if (p->iph.protocol == IPPROTO_IPV6 && (p->i_flags & SIT_ISATAP)) {
 310                 struct ip_tunnel_prl prl[16] = {};
 311                 int i;
 312
 313                 prl[0].datalen = sizeof(prl) - sizeof(prl[0]);
 314                 prl[0].addr = htonl(INADDR_ANY);
 315
 316                 if (!tnl_prl_ioctl(SIOCGETPRL, p->name, prl))
 317                         for (i = 1; i < ARRAY_SIZE(prl); i++) {
 318                                 if (prl[i].addr != htonl(INADDR_ANY)) {
 319                                         printf(" %s %s ",
 320                                                (prl[i].flags & PRL_DEFAULT) ? "pdr" : "pr",
 321                                                format_host(AF_INET, 4, &prl[i].addr));
 322                                 }
 323                         }
 324         }
 325
 326         if (p->link) {
 327                 const char *n = ll_index_to_name(p->link);
 328
 329                 if (n)
 330                         printf(" dev %s", n);
 331         }
 332
 333         if (p->iph.ttl)
 334                 printf(" ttl %d", p->iph.ttl);
 335         else
 336                 printf(" ttl inherit");
 337
 338         if (p->iph.tos) {
 339                 SPRINT_BUF(b1);
 340                 printf(" tos");
 341                 if (p->iph.tos & 1)
 342                         printf(" inherit");
 343                 if (p->iph.tos & ~1)
 344                         printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
 345                                rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
 346         }
 347
 348         if (!(p->iph.frag_off & htons(IP_DF)))
 349                 printf(" nopmtudisc");
 350
 351         if (p->iph.protocol == IPPROTO_IPV6 && !tnl_ioctl_get_6rd(p->name, &ip6rd) && ip6rd.prefixlen) {
 352                 printf(" 6rd-prefix %s/%u",
 353                        inet_ntop(AF_INET6, &ip6rd.prefix, s1, sizeof(s1)),
 354                        ip6rd.prefixlen);
 355                 if (ip6rd.relay_prefix) {
 356                         printf(" 6rd-relay_prefix %s/%u",
 357                                format_host(AF_INET, 4, &ip6rd.relay_prefix),
 358                                ip6rd.relay_prefixlen);
 359                 }
 360         }
 361
 362         if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
 363                 printf(" key %u", ntohl(p->i_key));
 364         else if ((p->i_flags | p->o_flags) & GRE_KEY) {
 365                 if (p->i_flags & GRE_KEY)
 366                         printf(" ikey %u", ntohl(p->i_key));
 367                 if (p->o_flags & GRE_KEY)
 368                         printf(" okey %u", ntohl(p->o_key));
 369         }
 370
 371         if (p->i_flags & GRE_SEQ)
 372                 printf("%s  Drop packets out of sequence.", _SL_);
 373         if (p->i_flags & GRE_CSUM)
 374                 printf("%s  Checksum in received packet is required.", _SL_);
 375         if (p->o_flags & GRE_SEQ)
 376                 printf("%s  Sequence packets on output.", _SL_);
 377         if (p->o_flags & GRE_CSUM)
 378                 printf("%s  Checksum output packets.", _SL_);
 379 }
 380
 381 static int do_tunnels_list(struct ip_tunnel_parm *p)
 382 {
 383         char buf[512];
 384         int err = -1;
 385         FILE *fp = fopen("/proc/net/dev", "r");
 386
 387         if (fp == NULL) {
 388                 perror("fopen");
 389                 return -1;
 390         }
 391
 392         /* skip header lines */
 393         if (!fgets(buf, sizeof(buf), fp) ||
 394             !fgets(buf, sizeof(buf), fp)) {
 395                 fprintf(stderr, "/proc/net/dev read error\n");
 396                 goto end;
 397         }
 398
 399         while (fgets(buf, sizeof(buf), fp) != NULL) {
 400                 char name[IFNAMSIZ];
 401                 int index, type;
 402                 struct ip_tunnel_parm p1 = {};
 403                 char *ptr;
 404
 405                 buf[sizeof(buf) - 1] = 0;
 406                 ptr = strchr(buf, ':');
 407                 if (ptr == NULL ||
 408                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 409                         fprintf(stderr, "Wrong format for /proc/net/dev. Giving up.\n");
 410                         goto end;
 411                 }
 412                 if (p->name[0] && strcmp(p->name, name))
 413                         continue;
 414                 index = ll_name_to_index(name);
 415                 if (index == 0)
 416                         continue;
 417                 type = ll_index_to_type(index);
 418                 if (type == -1) {
 419                         fprintf(stderr, "Failed to get type of \"%s\"\n", name);
 420                         continue;
 421                 }
 422                 if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
 423                         continue;
 424                 if (tnl_get_ioctl(name, &p1))
 425                         continue;
 426                 if ((p->link && p1.link != p->link) ||
 427                     (p->name[0] && strcmp(p1.name, p->name)) ||
 428                     (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
 429                     (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
 430                     (p->i_key && p1.i_key != p->i_key))
 431                         continue;
 432                 print_tunnel(&p1);
 433                 if (show_stats)
 434                         tnl_print_stats(ptr);
 435                 printf("\n");
 436         }
 437         err = 0;
 438  end:
 439         fclose(fp);
 440         return err;
 441 }
 442
 443 static int do_show(int argc, char **argv)
 444 {
 445         struct ip_tunnel_parm p;
 446         const char *basedev;
 447
 448         ll_init_map(&rth);
 449         if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)
 450                 return -1;
 451
 452         basedev = tnl_defname(&p);
 453         if (!basedev)
 454                 return do_tunnels_list(&p);
 455
 456         if (tnl_get_ioctl(p.name[0] ? p.name : basedev, &p))
 457                 return -1;
 458
 459         print_tunnel(&p);
 460         printf("\n");
 461         return 0;
 462 }
 463
 464 static int do_prl(int argc, char **argv)
 465 {
 466         struct ip_tunnel_prl p = {};
 467         int count = 0;
 468         int devname = 0;
 469         int cmd = 0;
 470         char medium[IFNAMSIZ] = {};
 471
 472         while (argc > 0) {
 473                 if (strcmp(*argv, "prl-default") == 0) {
 474                         NEXT_ARG();
 475                         cmd = SIOCADDPRL;
 476                         p.addr = get_addr32(*argv);
 477                         p.flags |= PRL_DEFAULT;
 478                         count++;
 479                 } else if (strcmp(*argv, "prl-nodefault") == 0) {
 480                         NEXT_ARG();
 481                         cmd = SIOCADDPRL;
 482                         p.addr = get_addr32(*argv);
 483                         count++;
 484                 } else if (strcmp(*argv, "prl-delete") == 0) {
 485                         NEXT_ARG();
 486                         cmd = SIOCDELPRL;
 487                         p.addr = get_addr32(*argv);
 488                         count++;
 489                 } else if (strcmp(*argv, "dev") == 0) {
 490                         NEXT_ARG();
 491                         strncpy(medium, *argv, IFNAMSIZ-1);
 492                         devname++;
 493                 } else {
 494                         fprintf(stderr,
 495                                 "Invalid PRL parameter \"%s\"\n", *argv);
 496                         exit(-1);
 497                 }
 498                 if (count > 1) {
 499                         fprintf(stderr,
 500                                 "One PRL entry at a time\n");
 501                         exit(-1);
 502                 }
 503                 argc--; argv++;
 504         }
 505         if (devname == 0) {
 506                 fprintf(stderr, "Must specify device\n");
 507                 exit(-1);
 508         }
 509
 510         return tnl_prl_ioctl(cmd, medium, &p);
 511 }
 512
 513 static int do_6rd(int argc, char **argv)
 514 {
 515         struct ip_tunnel_6rd ip6rd = {};
 516         int devname = 0;
 517         int cmd = 0;
 518         char medium[IFNAMSIZ] = {};
 519         inet_prefix prefix;
 520
 521         while (argc > 0) {
 522                 if (strcmp(*argv, "6rd-prefix") == 0) {
 523                         NEXT_ARG();
 524                         if (get_prefix(&prefix, *argv, AF_INET6))
 525                                 invarg("invalid 6rd_prefix\n", *argv);
 526                         cmd = SIOCADD6RD;
 527                         memcpy(&ip6rd.prefix, prefix.data, 16);
 528                         ip6rd.prefixlen = prefix.bitlen;
 529                 } else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
 530                         NEXT_ARG();
 531                         if (get_prefix(&prefix, *argv, AF_INET))
 532                                 invarg("invalid 6rd-relay_prefix\n", *argv);
 533                         cmd = SIOCADD6RD;
 534                         memcpy(&ip6rd.relay_prefix, prefix.data, 4);
 535                         ip6rd.relay_prefixlen = prefix.bitlen;
 536                 } else if (strcmp(*argv, "6rd-reset") == 0) {
 537                         cmd = SIOCDEL6RD;
 538                 } else if (strcmp(*argv, "dev") == 0) {
 539                         NEXT_ARG();
 540                         strncpy(medium, *argv, IFNAMSIZ-1);
 541                         devname++;
 542                 } else {
 543                         fprintf(stderr,
 544                                 "Invalid 6RD parameter \"%s\"\n", *argv);
 545                         exit(-1);
 546                 }
 547                 argc--; argv++;
 548         }
 549         if (devname == 0) {
 550                 fprintf(stderr, "Must specify device\n");
 551                 exit(-1);
 552         }
 553
 554         return tnl_6rd_ioctl(cmd, medium, &ip6rd);
 555 }
 556
 557 static int tunnel_mode_is_ipv6(char *tunnel_mode)
 558 {
 559         static const char * const ipv6_modes[] = {
 560                 "ipv6/ipv6", "ip6ip6",
 561                 "vti6",
 562                 "ip/ipv6", "ipv4/ipv6", "ipip6", "ip4ip6",
 563                 "ip6gre", "gre/ipv6",
 564                 "any/ipv6", "any"
 565         };
 566         int i;
 567
 568         for (i = 0; i < ARRAY_SIZE(ipv6_modes); i++) {
 569                 if (strcmp(ipv6_modes[i], tunnel_mode) == 0)
 570                         return 1;
 571         }
 572         return 0;
 573 }
 574
 575 int do_iptunnel(int argc, char **argv)
 576 {
 577         int i;
 578
 579         for (i = 0; i < argc - 1; i++) {
 580                 if (strcmp(argv[i], "mode") == 0) {
 581                         if (tunnel_mode_is_ipv6(argv[i + 1]))
 582                                 preferred_family = AF_INET6;
 583                         break;
 584                 }
 585         }
 586         switch (preferred_family) {
 587         case AF_UNSPEC:
 588                 preferred_family = AF_INET;
 589                 break;
 590         case AF_INET:
 591                 break;
 592         /*
 593          * This is silly enough but we have no easy way to make it
 594          * protocol-independent because of unarranged structure between
 595          * IPv4 and IPv6.
 596          */
 597         case AF_INET6:
 598                 return do_ip6tunnel(argc, argv);
 599         default:
 600                 fprintf(stderr, "Unsupported protocol family: %d\n", preferred_family);
 601                 exit(-1);
 602         }
 603
 604         if (argc > 0) {
 605                 if (matches(*argv, "add") == 0)
 606                         return do_add(SIOCADDTUNNEL, argc - 1, argv + 1);
 607                 if (matches(*argv, "change") == 0)
 608                         return do_add(SIOCCHGTUNNEL, argc - 1, argv + 1);
 609                 if (matches(*argv, "delete") == 0)
 610                         return do_del(argc - 1, argv + 1);
 611                 if (matches(*argv, "show") == 0 ||
 612                     matches(*argv, "lst") == 0 ||
 613                     matches(*argv, "list") == 0)
 614                         return do_show(argc - 1, argv + 1);
 615                 if (matches(*argv, "prl") == 0)
 616                         return do_prl(argc - 1, argv + 1);
 617                 if (matches(*argv, "6rd") == 0)
 618                         return do_6rd(argc - 1, argv + 1);
 619                 if (matches(*argv, "help") == 0)
 620                         usage();
 621         } else
 622                 return do_show(0, NULL);
 623
 624         fprintf(stderr, "Command \"%s\" is unknown, try \"ip tunnel help\"\n", *argv);
 625         exit(-1);
 626 }