ip/link_iptnl.c

   1 /*
   2  * link_iptnl.c ipip and sit driver module
   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:     Nicolas Dichtel <nicolas.dichtel@6wind.com>
  10  *
  11  */
  12
  13 #include <string.h>
  14 #include <net/if.h>
  15 #include <sys/types.h>
  16 #include <sys/socket.h>
  17 #include <arpa/inet.h>
  18
  19 #include <linux/in.h>
  20 #include <linux/ip.h>
  21 #include <linux/if_tunnel.h>
  22 #include "rt_names.h"
  23 #include "utils.h"
  24 #include "ip_common.h"
  25 #include "tunnel.h"
  26
  27 static void print_usage(FILE *f, int sit)
  28 {
  29         const char *type = sit ? "sit " : "ipip";
  30
  31         fprintf(f,
  32                 "Usage: ... %s [ remote ADDR ]\n"
  33                 "                [ local ADDR ]\n"
  34                 "                [ ttl TTL ]\n"
  35                 "                [ tos TOS ]\n"
  36                 "                [ [no]pmtudisc ]\n"
  37                 "                [ dev PHYS_DEV ]\n"
  38                 "                [ 6rd-prefix ADDR ]\n"
  39                 "                [ 6rd-relay_prefix ADDR ]\n"
  40                 "                [ 6rd-reset ]\n"
  41                 "                [ noencap ]\n"
  42                 "                [ encap { fou | gue | none } ]\n"
  43                 "                [ encap-sport PORT ]\n"
  44                 "                [ encap-dport PORT ]\n"
  45                 "                [ [no]encap-csum ]\n"
  46                 "                [ [no]encap-csum6 ]\n"
  47                 "                [ [no]encap-remcsum ]\n",
  48                 type
  49         );
  50         if (sit) {
  51                 fprintf(f, "          [ mode { ip6ip | ipip | mplsip | any } ]\n");
  52                 fprintf(f, "          [ isatap ]\n");
  53         } else {
  54                 fprintf(f, "          [ mode { ipip | mplsip | any } ]\n");
  55         }
  56         fprintf(f, "                [ external ]\n");
  57         fprintf(f, "                [ fwmark MARK ]\n");
  58         fprintf(f, "\n");
  59         fprintf(f, "Where: ADDR := { IP_ADDRESS | any }\n");
  60         fprintf(f, "       TOS  := { NUMBER | inherit }\n");
  61         fprintf(f, "       TTL  := { 1..255 | inherit }\n");
  62         fprintf(f, "       MARK := { 0x0..0xffffffff }\n");
  63 }
  64
  65 static void usage(int sit) __attribute__((noreturn));
  66 static void usage(int sit)
  67 {
  68         print_usage(stderr, sit);
  69         exit(-1);
  70 }
  71
  72 static int iptunnel_parse_opt(struct link_util *lu, int argc, char **argv,
  73                               struct nlmsghdr *n)
  74 {
  75         struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
  76         struct {
  77                 struct nlmsghdr n;
  78                 struct ifinfomsg i;
  79         } req = {
  80                 .n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)),
  81                 .n.nlmsg_flags = NLM_F_REQUEST,
  82                 .n.nlmsg_type = RTM_GETLINK,
  83                 .i.ifi_family = preferred_family,
  84                 .i.ifi_index = ifi->ifi_index,
  85         };
  86         struct nlmsghdr *answer;
  87         struct rtattr *tb[IFLA_MAX + 1];
  88         struct rtattr *linkinfo[IFLA_INFO_MAX+1];
  89         struct rtattr *iptuninfo[IFLA_IPTUN_MAX + 1];
  90         int len;
  91         __u32 link = 0;
  92         __u32 laddr = 0;
  93         __u32 raddr = 0;
  94         __u8 ttl = 0;
  95         __u8 tos = 0;
  96         __u8 pmtudisc = 1;
  97         __u16 iflags = 0;
  98         __u8 proto = 0;
  99         struct in6_addr ip6rdprefix = {};
 100         __u16 ip6rdprefixlen = 0;
 101         __u32 ip6rdrelayprefix = 0;
 102         __u16 ip6rdrelayprefixlen = 0;
 103         __u16 encaptype = 0;
 104         __u16 encapflags = 0;
 105         __u16 encapsport = 0;
 106         __u16 encapdport = 0;
 107         __u8 metadata = 0;
 108         __u32 fwmark = 0;
 109
 110         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 111                 if (rtnl_talk(&rth, &req.n, &answer) < 0) {
 112 get_failed:
 113                         fprintf(stderr,
 114                                 "Failed to get existing tunnel info.\n");
 115                         return -1;
 116                 }
 117
 118                 len = answer->nlmsg_len;
 119                 len -= NLMSG_LENGTH(sizeof(*ifi));
 120                 if (len < 0)
 121                         goto get_failed;
 122
 123                 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)), len);
 124
 125                 if (!tb[IFLA_LINKINFO])
 126                         goto get_failed;
 127
 128                 parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
 129
 130                 if (!linkinfo[IFLA_INFO_DATA])
 131                         goto get_failed;
 132
 133                 parse_rtattr_nested(iptuninfo, IFLA_IPTUN_MAX,
 134                                     linkinfo[IFLA_INFO_DATA]);
 135
 136                 if (iptuninfo[IFLA_IPTUN_LOCAL])
 137                         laddr = rta_getattr_u32(iptuninfo[IFLA_IPTUN_LOCAL]);
 138
 139                 if (iptuninfo[IFLA_IPTUN_REMOTE])
 140                         raddr = rta_getattr_u32(iptuninfo[IFLA_IPTUN_REMOTE]);
 141
 142                 if (iptuninfo[IFLA_IPTUN_TTL])
 143                         ttl = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TTL]);
 144
 145                 if (iptuninfo[IFLA_IPTUN_TOS])
 146                         tos = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TOS]);
 147
 148                 if (iptuninfo[IFLA_IPTUN_PMTUDISC])
 149                         pmtudisc =
 150                                 rta_getattr_u8(iptuninfo[IFLA_IPTUN_PMTUDISC]);
 151
 152                 if (iptuninfo[IFLA_IPTUN_FLAGS])
 153                         iflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_FLAGS]);
 154
 155                 if (iptuninfo[IFLA_IPTUN_LINK])
 156                         link = rta_getattr_u32(iptuninfo[IFLA_IPTUN_LINK]);
 157
 158                 if (iptuninfo[IFLA_IPTUN_PROTO])
 159                         proto = rta_getattr_u8(iptuninfo[IFLA_IPTUN_PROTO]);
 160
 161                 if (iptuninfo[IFLA_IPTUN_ENCAP_TYPE])
 162                         encaptype = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_TYPE]);
 163                 if (iptuninfo[IFLA_IPTUN_ENCAP_FLAGS])
 164                         encapflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_FLAGS]);
 165                 if (iptuninfo[IFLA_IPTUN_ENCAP_SPORT])
 166                         encapsport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_SPORT]);
 167                 if (iptuninfo[IFLA_IPTUN_ENCAP_DPORT])
 168                         encapdport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_DPORT]);
 169                 if (iptuninfo[IFLA_IPTUN_6RD_PREFIX])
 170                         memcpy(&ip6rdprefix,
 171                                RTA_DATA(iptuninfo[IFLA_IPTUN_6RD_PREFIX]),
 172                                sizeof(laddr));
 173
 174                 if (iptuninfo[IFLA_IPTUN_6RD_PREFIXLEN])
 175                         ip6rdprefixlen =
 176                                 rta_getattr_u16(iptuninfo[IFLA_IPTUN_6RD_PREFIXLEN]);
 177
 178                 if (iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIX])
 179                         ip6rdrelayprefix =
 180                                 rta_getattr_u32(iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIX]);
 181
 182                 if (iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN])
 183                         ip6rdrelayprefixlen =
 184                                 rta_getattr_u16(iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
 185                 if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
 186                         metadata = 1;
 187
 188                 if (iptuninfo[IFLA_IPTUN_FWMARK])
 189                         fwmark = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FWMARK]);
 190
 191                 free(answer);
 192         }
 193
 194         while (argc > 0) {
 195                 if (strcmp(*argv, "remote") == 0) {
 196                         NEXT_ARG();
 197                         raddr = get_addr32(*argv);
 198                 } else if (strcmp(*argv, "local") == 0) {
 199                         NEXT_ARG();
 200                         laddr = get_addr32(*argv);
 201                 } else if (matches(*argv, "dev") == 0) {
 202                         NEXT_ARG();
 203                         link = ll_name_to_index(*argv);
 204                         if (link == 0)
 205                                 invarg("\"dev\" is invalid", *argv);
 206                 } else if (strcmp(*argv, "ttl") == 0 ||
 207                            strcmp(*argv, "hoplimit") == 0 ||
 208                            strcmp(*argv, "hlim") == 0) {
 209                         NEXT_ARG();
 210                         if (strcmp(*argv, "inherit") != 0) {
 211                                 if (get_u8(&ttl, *argv, 0))
 212                                         invarg("invalid TTL\n", *argv);
 213                         } else
 214                                 ttl = 0;
 215                 } else if (strcmp(*argv, "tos") == 0 ||
 216                            strcmp(*argv, "tclass") == 0 ||
 217                            matches(*argv, "dsfield") == 0) {
 218                         __u32 uval;
 219
 220                         NEXT_ARG();
 221                         if (strcmp(*argv, "inherit") != 0) {
 222                                 if (rtnl_dsfield_a2n(&uval, *argv))
 223                                         invarg("bad TOS value", *argv);
 224                                 tos = uval;
 225                         } else
 226                                 tos = 1;
 227                 } else if (strcmp(*argv, "nopmtudisc") == 0) {
 228                         pmtudisc = 0;
 229                 } else if (strcmp(*argv, "pmtudisc") == 0) {
 230                         pmtudisc = 1;
 231                 } else if (strcmp(lu->id, "sit") == 0 &&
 232                            strcmp(*argv, "isatap") == 0) {
 233                         iflags |= SIT_ISATAP;
 234                 } else if (strcmp(*argv, "mode") == 0) {
 235                         NEXT_ARG();
 236                         if (strcmp(lu->id, "sit") == 0 &&
 237                             (strcmp(*argv, "ipv6/ipv4") == 0 ||
 238                              strcmp(*argv, "ip6ip") == 0))
 239                                 proto = IPPROTO_IPV6;
 240                         else if (strcmp(*argv, "ipv4/ipv4") == 0 ||
 241                                  strcmp(*argv, "ipip") == 0 ||
 242                                  strcmp(*argv, "ip4ip4") == 0)
 243                                 proto = IPPROTO_IPIP;
 244                         else if (strcmp(*argv, "mpls/ipv4") == 0 ||
 245                                    strcmp(*argv, "mplsip") == 0)
 246                                 proto = IPPROTO_MPLS;
 247                         else if (strcmp(*argv, "any/ipv4") == 0 ||
 248                                  strcmp(*argv, "any") == 0)
 249                                 proto = 0;
 250                         else
 251                                 invarg("Cannot guess tunnel mode.", *argv);
 252                 } else if (strcmp(*argv, "noencap") == 0) {
 253                         encaptype = TUNNEL_ENCAP_NONE;
 254                 } else if (strcmp(*argv, "encap") == 0) {
 255                         NEXT_ARG();
 256                         if (strcmp(*argv, "fou") == 0)
 257                                 encaptype = TUNNEL_ENCAP_FOU;
 258                         else if (strcmp(*argv, "gue") == 0)
 259                                 encaptype = TUNNEL_ENCAP_GUE;
 260                         else if (strcmp(*argv, "none") == 0)
 261                                 encaptype = TUNNEL_ENCAP_NONE;
 262                         else
 263                                 invarg("Invalid encap type.", *argv);
 264                 } else if (strcmp(*argv, "encap-sport") == 0) {
 265                         NEXT_ARG();
 266                         if (strcmp(*argv, "auto") == 0)
 267                                 encapsport = 0;
 268                         else if (get_u16(&encapsport, *argv, 0))
 269                                 invarg("Invalid source port.", *argv);
 270                 } else if (strcmp(*argv, "encap-dport") == 0) {
 271                         NEXT_ARG();
 272                         if (get_u16(&encapdport, *argv, 0))
 273                                 invarg("Invalid destination port.", *argv);
 274                 } else if (strcmp(*argv, "encap-csum") == 0) {
 275                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
 276                 } else if (strcmp(*argv, "noencap-csum") == 0) {
 277                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
 278                 } else if (strcmp(*argv, "encap-udp6-csum") == 0) {
 279                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
 280                 } else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
 281                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM6;
 282                 } else if (strcmp(*argv, "encap-remcsum") == 0) {
 283                         encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 284                 } else if (strcmp(*argv, "noencap-remcsum") == 0) {
 285                         encapflags &= ~TUNNEL_ENCAP_FLAG_REMCSUM;
 286                 } else if (strcmp(*argv, "external") == 0) {
 287                         metadata = 1;
 288                 } else if (strcmp(*argv, "6rd-prefix") == 0) {
 289                         inet_prefix prefix;
 290
 291                         NEXT_ARG();
 292                         if (get_prefix(&prefix, *argv, AF_INET6))
 293                                 invarg("invalid 6rd_prefix\n", *argv);
 294                         memcpy(&ip6rdprefix, prefix.data, 16);
 295                         ip6rdprefixlen = prefix.bitlen;
 296                 } else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
 297                         inet_prefix prefix;
 298
 299                         NEXT_ARG();
 300                         if (get_prefix(&prefix, *argv, AF_INET))
 301                                 invarg("invalid 6rd-relay_prefix\n", *argv);
 302                         memcpy(&ip6rdrelayprefix, prefix.data, 4);
 303                         ip6rdrelayprefixlen = prefix.bitlen;
 304                 } else if (strcmp(*argv, "6rd-reset") == 0) {
 305                         inet_prefix prefix;
 306
 307                         get_prefix(&prefix, "2002::", AF_INET6);
 308                         memcpy(&ip6rdprefix, prefix.data, 16);
 309                         ip6rdprefixlen = 16;
 310                         ip6rdrelayprefix = 0;
 311                         ip6rdrelayprefixlen = 0;
 312                 } else if (strcmp(*argv, "fwmark") == 0) {
 313                         NEXT_ARG();
 314                         if (get_u32(&fwmark, *argv, 0))
 315                                 invarg("invalid fwmark\n", *argv);
 316                 } else
 317                         usage(strcmp(lu->id, "sit") == 0);
 318                 argc--, argv++;
 319         }
 320
 321         if (ttl && pmtudisc == 0) {
 322                 fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
 323                 exit(-1);
 324         }
 325
 326         addattr8(n, 1024, IFLA_IPTUN_PROTO, proto);
 327         if (metadata) {
 328                 addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
 329                 return 0;
 330         }
 331
 332         addattr32(n, 1024, IFLA_IPTUN_LINK, link);
 333         addattr32(n, 1024, IFLA_IPTUN_LOCAL, laddr);
 334         addattr32(n, 1024, IFLA_IPTUN_REMOTE, raddr);
 335         addattr8(n, 1024, IFLA_IPTUN_TTL, ttl);
 336         addattr8(n, 1024, IFLA_IPTUN_TOS, tos);
 337         addattr8(n, 1024, IFLA_IPTUN_PMTUDISC, pmtudisc);
 338         addattr32(n, 1024, IFLA_IPTUN_FWMARK, fwmark);
 339
 340         addattr16(n, 1024, IFLA_IPTUN_ENCAP_TYPE, encaptype);
 341         addattr16(n, 1024, IFLA_IPTUN_ENCAP_FLAGS, encapflags);
 342         addattr16(n, 1024, IFLA_IPTUN_ENCAP_SPORT, htons(encapsport));
 343         addattr16(n, 1024, IFLA_IPTUN_ENCAP_DPORT, htons(encapdport));
 344
 345         if (strcmp(lu->id, "sit") == 0) {
 346                 addattr16(n, 1024, IFLA_IPTUN_FLAGS, iflags);
 347                 if (ip6rdprefixlen) {
 348                         addattr_l(n, 1024, IFLA_IPTUN_6RD_PREFIX,
 349                                   &ip6rdprefix, sizeof(ip6rdprefix));
 350                         addattr16(n, 1024, IFLA_IPTUN_6RD_PREFIXLEN,
 351                                   ip6rdprefixlen);
 352                         addattr32(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIX,
 353                                   ip6rdrelayprefix);
 354                         addattr16(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
 355                                   ip6rdrelayprefixlen);
 356                 }
 357         }
 358
 359         return 0;
 360 }
 361
 362 static void iptunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 363 {
 364         char s2[64];
 365         __u16 prefixlen;
 366         __u8 ttl = 0;
 367         __u8 tos = 0;
 368
 369         if (!tb)
 370                 return;
 371
 372         if (tb[IFLA_IPTUN_COLLECT_METADATA]) {
 373                 print_bool(PRINT_ANY, "external", "external", true);
 374                 return;
 375         }
 376
 377         if (tb[IFLA_IPTUN_PROTO]) {
 378                 switch (rta_getattr_u8(tb[IFLA_IPTUN_PROTO])) {
 379                 case IPPROTO_IPIP:
 380                         print_string(PRINT_ANY, "proto", "%s ", "ipip");
 381                         break;
 382                 case IPPROTO_IPV6:
 383                         print_string(PRINT_ANY, "proto", "%s ", "ip6ip");
 384                         break;
 385                 case IPPROTO_MPLS:
 386                         print_string(PRINT_ANY, "proto", "%s ", "mplsip");
 387                         break;
 388                 case 0:
 389                         print_string(PRINT_ANY, "proto", "%s ", "any");
 390                         break;
 391                 }
 392         }
 393
 394         tnl_print_endpoint("remote", tb[IFLA_IPTUN_REMOTE], AF_INET);
 395         tnl_print_endpoint("local", tb[IFLA_IPTUN_LOCAL], AF_INET);
 396
 397         if (tb[IFLA_IPTUN_LINK]) {
 398                 unsigned int link = rta_getattr_u32(tb[IFLA_IPTUN_LINK]);
 399
 400                 if (link) {
 401                         print_string(PRINT_ANY, "link", "dev %s ",
 402                                      ll_index_to_name(link));
 403                 }
 404         }
 405
 406         if (tb[IFLA_IPTUN_TTL])
 407                 ttl = rta_getattr_u8(tb[IFLA_IPTUN_TTL]);
 408         if (is_json_context() || ttl)
 409                 print_uint(PRINT_ANY, "ttl", "ttl %u ", ttl);
 410         else
 411                 print_string(PRINT_FP, NULL, "ttl %s ", "inherit");
 412
 413         if (tb[IFLA_IPTUN_TOS])
 414                 tos = rta_getattr_u8(tb[IFLA_IPTUN_TOS]);
 415         if (tos) {
 416                 if (is_json_context() || tos != 1)
 417                         print_0xhex(PRINT_ANY, "tos", "tos 0x%x ", tos);
 418                 else
 419                         print_string(PRINT_FP, NULL, "tos %s ", "inherit");
 420         }
 421
 422         if (tb[IFLA_IPTUN_PMTUDISC] && rta_getattr_u8(tb[IFLA_IPTUN_PMTUDISC]))
 423                 print_bool(PRINT_ANY, "pmtudisc", "pmtudisc ", true);
 424         else
 425                 print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);
 426
 427         if (tb[IFLA_IPTUN_FLAGS]) {
 428                 __u16 iflags = rta_getattr_u16(tb[IFLA_IPTUN_FLAGS]);
 429
 430                 if (iflags & SIT_ISATAP)
 431                         print_bool(PRINT_ANY, "isatap", "isatap ", true);
 432         }
 433
 434         if (tb[IFLA_IPTUN_6RD_PREFIXLEN] &&
 435             (prefixlen = rta_getattr_u16(tb[IFLA_IPTUN_6RD_PREFIXLEN]))) {
 436                 __u16 relayprefixlen =
 437                         rta_getattr_u16(tb[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
 438                 __u32 relayprefix =
 439                         rta_getattr_u32(tb[IFLA_IPTUN_6RD_RELAY_PREFIX]);
 440
 441                 const char *prefix = inet_ntop(AF_INET6,
 442                                                RTA_DATA(tb[IFLA_IPTUN_6RD_PREFIX]),
 443                                                s2, sizeof(s2));
 444
 445                 if (is_json_context()) {
 446                         print_string(PRINT_JSON, "prefix", NULL, prefix);
 447                         print_int(PRINT_JSON, "prefixlen", NULL, prefixlen);
 448                         if (relayprefix) {
 449                                 print_string(PRINT_JSON,
 450                                              "relay_prefix",
 451                                              NULL,
 452                                              format_host(AF_INET,
 453                                                          4,
 454                                                          &relayprefix));
 455                                 print_int(PRINT_JSON,
 456                                           "relay_prefixlen",
 457                                           NULL,
 458                                           relayprefixlen);
 459                         }
 460                 } else {
 461                         printf("6rd-prefix %s/%u ", prefix, prefixlen);
 462                         if (relayprefix) {
 463                                 printf("6rd-relay_prefix %s/%u ",
 464                                        format_host(AF_INET, 4, &relayprefix),
 465                                        relayprefixlen);
 466                         }
 467                 }
 468         }
 469
 470         if (tb[IFLA_IPTUN_FWMARK]) {
 471                 __u32 fwmark = rta_getattr_u32(tb[IFLA_IPTUN_FWMARK]);
 472
 473                 if (fwmark) {
 474                         print_0xhex(PRINT_ANY,
 475                                     "fwmark", "fwmark 0x%x ", fwmark);
 476                 }
 477         }
 478
 479         tnl_print_encap(tb,
 480                         IFLA_IPTUN_ENCAP_TYPE,
 481                         IFLA_IPTUN_ENCAP_FLAGS,
 482                         IFLA_IPTUN_ENCAP_SPORT,
 483                         IFLA_IPTUN_ENCAP_DPORT);
 484 }
 485
 486 static void iptunnel_print_help(struct link_util *lu, int argc, char **argv,
 487         FILE *f)
 488 {
 489         print_usage(f, strcmp(lu->id, "sit") == 0);
 490 }
 491
 492 struct link_util ipip_link_util = {
 493         .id = "ipip",
 494         .maxattr = IFLA_IPTUN_MAX,
 495         .parse_opt = iptunnel_parse_opt,
 496         .print_opt = iptunnel_print_opt,
 497         .print_help = iptunnel_print_help,
 498 };
 499
 500 struct link_util sit_link_util = {
 501         .id = "sit",
 502         .maxattr = IFLA_IPTUN_MAX,
 503         .parse_opt = iptunnel_parse_opt,
 504         .print_opt = iptunnel_print_opt,
 505         .print_help = iptunnel_print_help,
 506 };