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         memset(&medium, 0, sizeof(medium));
  68
  69         p->iph.version = 4;
  70         p->iph.ihl = 5;
  71 #ifndef IP_DF
  72 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  73 #endif
  74         p->iph.frag_off = htons(IP_DF);
  75
  76         while (argc > 0) {
  77                 if (strcmp(*argv, "mode") == 0) {
  78                         NEXT_ARG();
  79                         if (strcmp(*argv, "ipip") == 0 ||
  80                             strcmp(*argv, "ip/ip") == 0) {
  81                                 set_tunnel_proto(p, IPPROTO_IPIP);
  82                         } else if (strcmp(*argv, "gre") == 0 ||
  83                                    strcmp(*argv, "gre/ip") == 0) {
  84                                 set_tunnel_proto(p, IPPROTO_GRE);
  85                         } else if (strcmp(*argv, "sit") == 0 ||
  86                                    strcmp(*argv, "ipv6/ip") == 0) {
  87                                 set_tunnel_proto(p, IPPROTO_IPV6);
  88                         } else if (strcmp(*argv, "isatap") == 0) {
  89                                 set_tunnel_proto(p, IPPROTO_IPV6);
  90                                 isatap++;
  91                         } else if (strcmp(*argv, "vti") == 0) {
  92                                 set_tunnel_proto(p, IPPROTO_IPIP);
  93                                 p->i_flags |= VTI_ISVTI;
  94                         } else {
  95                                 fprintf(stderr,
  96                                         "Unknown tunnel mode \"%s\"\n", *argv);
  97                                 exit(-1);
  98                         }
  99                 } else if (strcmp(*argv, "key") == 0) {
 100                         NEXT_ARG();
 101                         p->i_flags |= GRE_KEY;
 102                         p->o_flags |= GRE_KEY;
 103                         p->i_key = p->o_key = tnl_parse_key("key", *argv);
 104                 } else if (strcmp(*argv, "ikey") == 0) {
 105                         NEXT_ARG();
 106                         p->i_flags |= GRE_KEY;
 107                         p->i_key = tnl_parse_key("ikey", *argv);
 108                 } else if (strcmp(*argv, "okey") == 0) {
 109                         NEXT_ARG();
 110                         p->o_flags |= GRE_KEY;
 111                         p->o_key = tnl_parse_key("okey", *argv);
 112                 } else if (strcmp(*argv, "seq") == 0) {
 113                         p->i_flags |= GRE_SEQ;
 114                         p->o_flags |= GRE_SEQ;
 115                 } else if (strcmp(*argv, "iseq") == 0) {
 116                         p->i_flags |= GRE_SEQ;
 117                 } else if (strcmp(*argv, "oseq") == 0) {
 118                         p->o_flags |= GRE_SEQ;
 119                 } else if (strcmp(*argv, "csum") == 0) {
 120                         p->i_flags |= GRE_CSUM;
 121                         p->o_flags |= GRE_CSUM;
 122                 } else if (strcmp(*argv, "icsum") == 0) {
 123                         p->i_flags |= GRE_CSUM;
 124                 } else if (strcmp(*argv, "ocsum") == 0) {
 125                         p->o_flags |= GRE_CSUM;
 126                 } else if (strcmp(*argv, "nopmtudisc") == 0) {
 127                         p->iph.frag_off = 0;
 128                 } else if (strcmp(*argv, "pmtudisc") == 0) {
 129                         p->iph.frag_off = htons(IP_DF);
 130                 } else if (strcmp(*argv, "remote") == 0) {
 131                         NEXT_ARG();
 132                         if (strcmp(*argv, "any"))
 133                                 p->iph.daddr = get_addr32(*argv);
 134                         else
 135                                 p->iph.daddr = htonl(INADDR_ANY);
 136                 } else if (strcmp(*argv, "local") == 0) {
 137                         NEXT_ARG();
 138                         if (strcmp(*argv, "any"))
 139                                 p->iph.saddr = get_addr32(*argv);
 140                         else
 141                                 p->iph.saddr = htonl(INADDR_ANY);
 142                 } else if (strcmp(*argv, "dev") == 0) {
 143                         NEXT_ARG();
 144                         strncpy(medium, *argv, IFNAMSIZ - 1);
 145                 } else if (strcmp(*argv, "ttl") == 0 ||
 146                            strcmp(*argv, "hoplimit") == 0 ||
 147                            strcmp(*argv, "hlim") == 0) {
 148                         __u8 uval;
 149
 150                         NEXT_ARG();
 151                         if (strcmp(*argv, "inherit") != 0) {
 152                                 if (get_u8(&uval, *argv, 0))
 153                                         invarg("invalid TTL\n", *argv);
 154                                 p->iph.ttl = uval;
 155                         }
 156                 } else if (strcmp(*argv, "tos") == 0 ||
 157                            strcmp(*argv, "tclass") == 0 ||
 158                            matches(*argv, "dsfield") == 0) {
 159                         char *dsfield;
 160                         __u32 uval;
 161
 162                         NEXT_ARG();
 163                         dsfield = *argv;
 164                         strsep(&dsfield, "/");
 165                         if (strcmp(*argv, "inherit") != 0) {
 166                                 dsfield = *argv;
 167                                 p->iph.tos = 0;
 168                         } else
 169                                 p->iph.tos = 1;
 170                         if (dsfield) {
 171                                 if (rtnl_dsfield_a2n(&uval, dsfield))
 172                                         invarg("bad TOS value", *argv);
 173                                 p->iph.tos |= uval;
 174                         }
 175                 } else {
 176                         if (strcmp(*argv, "name") == 0)
 177                                 NEXT_ARG();
 178                         else if (matches(*argv, "help") == 0)
 179                                 usage();
 180
 181                         if (p->name[0])
 182                                 duparg2("name", *argv);
 183                         strncpy(p->name, *argv, IFNAMSIZ - 1);
 184                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 185                                 struct ip_tunnel_parm old_p;
 186
 187                                 memset(&old_p, 0, sizeof(old_p));
 188                                 if (tnl_get_ioctl(*argv, &old_p))
 189                                         return -1;
 190                                 *p = old_p;
 191                         }
 192                 }
 193                 count++;
 194                 argc--; argv++;
 195         }
 196
 197
 198         if (p->iph.protocol == 0) {
 199                 if (memcmp(p->name, "gre", 3) == 0)
 200                         p->iph.protocol = IPPROTO_GRE;
 201                 else if (memcmp(p->name, "ipip", 4) == 0)
 202                         p->iph.protocol = IPPROTO_IPIP;
 203                 else if (memcmp(p->name, "sit", 3) == 0)
 204                         p->iph.protocol = IPPROTO_IPV6;
 205                 else if (memcmp(p->name, "isatap", 6) == 0) {
 206                         p->iph.protocol = IPPROTO_IPV6;
 207                         isatap++;
 208                 } else if (memcmp(p->name, "vti", 3) == 0) {
 209                         p->iph.protocol = IPPROTO_IPIP;
 210                         p->i_flags |= VTI_ISVTI;
 211                 }
 212         }
 213
 214         if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 215                 if (!(p->i_flags & VTI_ISVTI) &&
 216                     (p->iph.protocol != IPPROTO_GRE)) {
 217                         fprintf(stderr, "Keys are not allowed with ipip and sit tunnels\n");
 218                         return -1;
 219                 }
 220         }
 221
 222         if (medium[0]) {
 223                 p->link = ll_name_to_index(medium);
 224                 if (p->link == 0) {
 225                         fprintf(stderr, "Cannot find device \"%s\"\n", medium);
 226                         return -1;
 227                 }
 228         }
 229
 230         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 231                 p->i_key = p->iph.daddr;
 232                 p->i_flags |= GRE_KEY;
 233         }
 234         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 235                 p->o_key = p->iph.daddr;
 236                 p->o_flags |= GRE_KEY;
 237         }
 238         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 239                 fprintf(stderr, "A broadcast tunnel requires a source address\n");
 240                 return -1;
 241         }
 242         if (isatap)
 243                 p->i_flags |= SIT_ISATAP;
 244
 245         return 0;
 246 }
 247
 248 static const char *tnl_defname(const struct ip_tunnel_parm *p)
 249 {
 250         switch (p->iph.protocol) {
 251         case IPPROTO_IPIP:
 252                 if (p->i_flags & VTI_ISVTI)
 253                         return "ip_vti0";
 254                 else
 255                         return "tunl0";
 256         case IPPROTO_GRE:
 257                 return "gre0";
 258         case IPPROTO_IPV6:
 259                 return "sit0";
 260         }
 261         return NULL;
 262 }
 263
 264 static int do_add(int cmd, int argc, char **argv)
 265 {
 266         struct ip_tunnel_parm p;
 267         const char *basedev;
 268
 269         if (parse_args(argc, argv, cmd, &p) < 0)
 270                 return -1;
 271
 272         if (p.iph.ttl && p.iph.frag_off == 0) {
 273                 fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
 274                 return -1;
 275         }
 276
 277         basedev = tnl_defname(&p);
 278         if (!basedev) {
 279                 fprintf(stderr,
 280                         "cannot determine tunnel mode (ipip, gre, vti or sit)\n");
 281                 return -1;
 282         }
 283
 284         return tnl_add_ioctl(cmd, basedev, p.name, &p);
 285 }
 286
 287 static int do_del(int argc, char **argv)
 288 {
 289         struct ip_tunnel_parm p;
 290
 291         if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)
 292                 return -1;
 293
 294         return tnl_del_ioctl(tnl_defname(&p) ? : p.name, p.name, &p);
 295 }
 296
 297 static void print_tunnel(struct ip_tunnel_parm *p)
 298 {
 299         struct ip_tunnel_6rd ip6rd;
 300         char s1[1024];
 301         char s2[1024];
 302
 303         memset(&ip6rd, 0, sizeof(ip6rd));
 304
 305         /* Do not use format_host() for local addr,
 306          * symbolic name will not be useful.
 307          */
 308         printf("%s: %s/ip remote %s local %s",
 309                p->name,
 310                tnl_strproto(p->iph.protocol),
 311                p->iph.daddr ? format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1)) : "any",
 312                p->iph.saddr ? rt_addr_n2a(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2)) : "any");
 313
 314         if (p->iph.protocol == IPPROTO_IPV6 && (p->i_flags & SIT_ISATAP)) {
 315                 struct ip_tunnel_prl prl[16];
 316                 int i;
 317
 318                 memset(prl, 0, sizeof(prl));
 319                 prl[0].datalen = sizeof(prl) - sizeof(prl[0]);
 320                 prl[0].addr = htonl(INADDR_ANY);
 321
 322                 if (!tnl_prl_ioctl(SIOCGETPRL, p->name, prl))
 323                         for (i = 1; i < ARRAY_SIZE(prl); i++) {
 324                                 if (prl[i].addr != htonl(INADDR_ANY)) {
 325                                         printf(" %s %s ",
 326                                                (prl[i].flags & PRL_DEFAULT) ? "pdr" : "pr",
 327                                                format_host(AF_INET, 4, &prl[i].addr, s1, sizeof(s1)));
 328                                 }
 329                         }
 330         }
 331
 332         if (p->link) {
 333                 const char *n = ll_index_to_name(p->link);
 334
 335                 if (n)
 336                         printf(" dev %s", n);
 337         }
 338
 339         if (p->iph.ttl)
 340                 printf(" ttl %d", p->iph.ttl);
 341         else
 342                 printf(" ttl inherit");
 343
 344         if (p->iph.tos) {
 345                 SPRINT_BUF(b1);
 346                 printf(" tos");
 347                 if (p->iph.tos & 1)
 348                         printf(" inherit");
 349                 if (p->iph.tos & ~1)
 350                         printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
 351                                rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
 352         }
 353
 354         if (!(p->iph.frag_off & htons(IP_DF)))
 355                 printf(" nopmtudisc");
 356
 357         if (p->iph.protocol == IPPROTO_IPV6 && !tnl_ioctl_get_6rd(p->name, &ip6rd) && ip6rd.prefixlen) {
 358                 printf(" 6rd-prefix %s/%u",
 359                        inet_ntop(AF_INET6, &ip6rd.prefix, s1, sizeof(s1)),
 360                        ip6rd.prefixlen);
 361                 if (ip6rd.relay_prefix) {
 362                         printf(" 6rd-relay_prefix %s/%u",
 363                                format_host(AF_INET, 4, &ip6rd.relay_prefix, s1, sizeof(s1)),
 364                                ip6rd.relay_prefixlen);
 365                 }
 366         }
 367
 368         if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
 369                 printf(" key %u", ntohl(p->i_key));
 370         else if ((p->i_flags | p->o_flags) & GRE_KEY) {
 371                 if (p->i_flags & GRE_KEY)
 372                         printf(" ikey %u", ntohl(p->i_key));
 373                 if (p->o_flags & GRE_KEY)
 374                         printf(" okey %u", ntohl(p->o_key));
 375         }
 376
 377         if (p->i_flags & GRE_SEQ)
 378                 printf("%s  Drop packets out of sequence.", _SL_);
 379         if (p->i_flags & GRE_CSUM)
 380                 printf("%s  Checksum in received packet is required.", _SL_);
 381         if (p->o_flags & GRE_SEQ)
 382                 printf("%s  Sequence packets on output.", _SL_);
 383         if (p->o_flags & GRE_CSUM)
 384                 printf("%s  Checksum output packets.", _SL_);
 385 }
 386
 387 static int do_tunnels_list(struct ip_tunnel_parm *p)
 388 {
 389         char buf[512];
 390         int err = -1;
 391         FILE *fp = fopen("/proc/net/dev", "r");
 392
 393         if (fp == NULL) {
 394                 perror("fopen");
 395                 return -1;
 396         }
 397
 398         /* skip header lines */
 399         if (!fgets(buf, sizeof(buf), fp) ||
 400             !fgets(buf, sizeof(buf), fp)) {
 401                 fprintf(stderr, "/proc/net/dev read error\n");
 402                 goto end;
 403         }
 404
 405         while (fgets(buf, sizeof(buf), fp) != NULL) {
 406                 char name[IFNAMSIZ];
 407                 int index, type;
 408                 unsigned long rx_bytes, rx_packets, rx_errs, rx_drops,
 409                         rx_fifo, rx_frame,
 410                         tx_bytes, tx_packets, tx_errs, tx_drops,
 411                         tx_fifo, tx_colls, tx_carrier, rx_multi;
 412                 struct ip_tunnel_parm p1;
 413                 char *ptr;
 414
 415                 buf[sizeof(buf) - 1] = 0;
 416                 ptr = strchr(buf, ':');
 417                 if (ptr == NULL ||
 418                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 419                         fprintf(stderr, "Wrong format for /proc/net/dev. Giving up.\n");
 420                         goto end;
 421                 }
 422                 if (sscanf(ptr, "%lu%lu%lu%lu%lu%lu%lu%*d%lu%lu%lu%lu%lu%lu%lu",
 423                            &rx_bytes, &rx_packets, &rx_errs, &rx_drops,
 424                            &rx_fifo, &rx_frame, &rx_multi,
 425                            &tx_bytes, &tx_packets, &tx_errs, &tx_drops,
 426                            &tx_fifo, &tx_colls, &tx_carrier) != 14)
 427                         continue;
 428                 if (p->name[0] && strcmp(p->name, name))
 429                         continue;
 430                 index = ll_name_to_index(name);
 431                 if (index == 0)
 432                         continue;
 433                 type = ll_index_to_type(index);
 434                 if (type == -1) {
 435                         fprintf(stderr, "Failed to get type of \"%s\"\n", name);
 436                         continue;
 437                 }
 438                 if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
 439                         continue;
 440                 memset(&p1, 0, sizeof(p1));
 441                 if (tnl_get_ioctl(name, &p1))
 442                         continue;
 443                 if ((p->link && p1.link != p->link) ||
 444                     (p->name[0] && strcmp(p1.name, p->name)) ||
 445                     (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
 446                     (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
 447                     (p->i_key && p1.i_key != p->i_key))
 448                         continue;
 449                 print_tunnel(&p1);
 450                 if (show_stats) {
 451                         printf("%s", _SL_);
 452                         printf("RX: Packets    Bytes        Errors CsumErrs OutOfSeq Mcasts%s", _SL_);
 453                         printf("    %-10ld %-12ld %-6ld %-8ld %-8ld %-8ld%s",
 454                                rx_packets, rx_bytes, rx_errs, rx_frame, rx_fifo, rx_multi, _SL_);
 455                         printf("TX: Packets    Bytes        Errors DeadLoop NoRoute  NoBufs%s", _SL_);
 456                         printf("    %-10ld %-12ld %-6ld %-8ld %-8ld %-6ld",
 457                                tx_packets, tx_bytes, tx_errs, tx_colls, tx_carrier, tx_drops);
 458                 }
 459                 printf("\n");
 460         }
 461         err = 0;
 462  end:
 463         fclose(fp);
 464         return err;
 465 }
 466
 467 static int do_show(int argc, char **argv)
 468 {
 469         struct ip_tunnel_parm p;
 470         const char *basedev;
 471
 472         ll_init_map(&rth);
 473         if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)
 474                 return -1;
 475
 476         basedev = tnl_defname(&p);
 477         if (!basedev)
 478                 return do_tunnels_list(&p);
 479
 480         if (tnl_get_ioctl(p.name[0] ? p.name : basedev, &p))
 481                 return -1;
 482
 483         print_tunnel(&p);
 484         printf("\n");
 485         return 0;
 486 }
 487
 488 static int do_prl(int argc, char **argv)
 489 {
 490         struct ip_tunnel_prl p;
 491         int count = 0;
 492         int devname = 0;
 493         int cmd = 0;
 494         char medium[IFNAMSIZ];
 495
 496         memset(&p, 0, sizeof(p));
 497         memset(&medium, 0, sizeof(medium));
 498
 499         while (argc > 0) {
 500                 if (strcmp(*argv, "prl-default") == 0) {
 501                         NEXT_ARG();
 502                         cmd = SIOCADDPRL;
 503                         p.addr = get_addr32(*argv);
 504                         p.flags |= PRL_DEFAULT;
 505                         count++;
 506                 } else if (strcmp(*argv, "prl-nodefault") == 0) {
 507                         NEXT_ARG();
 508                         cmd = SIOCADDPRL;
 509                         p.addr = get_addr32(*argv);
 510                         count++;
 511                 } else if (strcmp(*argv, "prl-delete") == 0) {
 512                         NEXT_ARG();
 513                         cmd = SIOCDELPRL;
 514                         p.addr = get_addr32(*argv);
 515                         count++;
 516                 } else if (strcmp(*argv, "dev") == 0) {
 517                         NEXT_ARG();
 518                         strncpy(medium, *argv, IFNAMSIZ-1);
 519                         devname++;
 520                 } else {
 521                         fprintf(stderr,
 522                                 "Invalid PRL parameter \"%s\"\n", *argv);
 523                         exit(-1);
 524                 }
 525                 if (count > 1) {
 526                         fprintf(stderr,
 527                                 "One PRL entry at a time\n");
 528                         exit(-1);
 529                 }
 530                 argc--; argv++;
 531         }
 532         if (devname == 0) {
 533                 fprintf(stderr, "Must specify device\n");
 534                 exit(-1);
 535         }
 536
 537         return tnl_prl_ioctl(cmd, medium, &p);
 538 }
 539
 540 static int do_6rd(int argc, char **argv)
 541 {
 542         struct ip_tunnel_6rd ip6rd;
 543         int devname = 0;
 544         int cmd = 0;
 545         char medium[IFNAMSIZ];
 546         inet_prefix prefix;
 547
 548         memset(&ip6rd, 0, sizeof(ip6rd));
 549         memset(&medium, 0, sizeof(medium));
 550
 551         while (argc > 0) {
 552                 if (strcmp(*argv, "6rd-prefix") == 0) {
 553                         NEXT_ARG();
 554                         if (get_prefix(&prefix, *argv, AF_INET6))
 555                                 invarg("invalid 6rd_prefix\n", *argv);
 556                         cmd = SIOCADD6RD;
 557                         memcpy(&ip6rd.prefix, prefix.data, 16);
 558                         ip6rd.prefixlen = prefix.bitlen;
 559                 } else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
 560                         NEXT_ARG();
 561                         if (get_prefix(&prefix, *argv, AF_INET))
 562                                 invarg("invalid 6rd-relay_prefix\n", *argv);
 563                         cmd = SIOCADD6RD;
 564                         memcpy(&ip6rd.relay_prefix, prefix.data, 4);
 565                         ip6rd.relay_prefixlen = prefix.bitlen;
 566                 } else if (strcmp(*argv, "6rd-reset") == 0) {
 567                         cmd = SIOCDEL6RD;
 568                 } else if (strcmp(*argv, "dev") == 0) {
 569                         NEXT_ARG();
 570                         strncpy(medium, *argv, IFNAMSIZ-1);
 571                         devname++;
 572                 } else {
 573                         fprintf(stderr,
 574                                 "Invalid 6RD parameter \"%s\"\n", *argv);
 575                         exit(-1);
 576                 }
 577                 argc--; argv++;
 578         }
 579         if (devname == 0) {
 580                 fprintf(stderr, "Must specify device\n");
 581                 exit(-1);
 582         }
 583
 584         return tnl_6rd_ioctl(cmd, medium, &ip6rd);
 585 }
 586
 587 static int tunnel_mode_is_ipv6(char *tunnel_mode)
 588 {
 589         static const char * const ipv6_modes[] = {
 590                 "ipv6/ipv6", "ip6ip6",
 591                 "vti6",
 592                 "ip/ipv6", "ipv4/ipv6", "ipip6", "ip4ip6",
 593                 "ip6gre", "gre/ipv6",
 594                 "any/ipv6", "any"
 595         };
 596         int i;
 597
 598         for (i = 0; i < ARRAY_SIZE(ipv6_modes); i++) {
 599                 if (strcmp(ipv6_modes[i], tunnel_mode) == 0)
 600                         return 1;
 601         }
 602         return 0;
 603 }
 604
 605 int do_iptunnel(int argc, char **argv)
 606 {
 607         int i;
 608
 609         for (i = 0; i < argc - 1; i++) {
 610                 if (strcmp(argv[i], "mode") == 0) {
 611                         if (tunnel_mode_is_ipv6(argv[i + 1]))
 612                                 preferred_family = AF_INET6;
 613                         break;
 614                 }
 615         }
 616         switch (preferred_family) {
 617         case AF_UNSPEC:
 618                 preferred_family = AF_INET;
 619                 break;
 620         case AF_INET:
 621                 break;
 622         /*
 623          * This is silly enough but we have no easy way to make it
 624          * protocol-independent because of unarranged structure between
 625          * IPv4 and IPv6.
 626          */
 627         case AF_INET6:
 628                 return do_ip6tunnel(argc, argv);
 629         default:
 630                 fprintf(stderr, "Unsupported protocol family: %d\n", preferred_family);
 631                 exit(-1);
 632         }
 633
 634         if (argc > 0) {
 635                 if (matches(*argv, "add") == 0)
 636                         return do_add(SIOCADDTUNNEL, argc - 1, argv + 1);
 637                 if (matches(*argv, "change") == 0)
 638                         return do_add(SIOCCHGTUNNEL, argc - 1, argv + 1);
 639                 if (matches(*argv, "delete") == 0)
 640                         return do_del(argc - 1, argv + 1);
 641                 if (matches(*argv, "show") == 0 ||
 642                     matches(*argv, "lst") == 0 ||
 643                     matches(*argv, "list") == 0)
 644                         return do_show(argc - 1, argv + 1);
 645                 if (matches(*argv, "prl") == 0)
 646                         return do_prl(argc - 1, argv + 1);
 647                 if (matches(*argv, "6rd") == 0)
 648                         return do_6rd(argc - 1, argv + 1);
 649                 if (matches(*argv, "help") == 0)
 650                         usage();
 651         } else
 652                 return do_show(0, NULL);
 653
 654         fprintf(stderr, "Command \"%s\" is unknown, try \"ip tunnel help\"\n", *argv);
 655         exit(-1);
 656 }