ip/link_ip6tnl.c

   1 /*
   2  * link_ip6tnl.c        ip6tnl 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/ip.h>
  20 #include <linux/if_tunnel.h>
  21 #include <linux/ip6_tunnel.h>
  22 #include "rt_names.h"
  23 #include "utils.h"
  24 #include "ip_common.h"
  25 #include "tunnel.h"
  26
  27 #define IP6_FLOWINFO_TCLASS     htonl(0x0FF00000)
  28 #define IP6_FLOWINFO_FLOWLABEL  htonl(0x000FFFFF)
  29
  30 #define DEFAULT_TNL_HOP_LIMIT   (64)
  31
  32 static void print_usage(FILE *f)
  33 {
  34         fprintf(f,
  35                 "Usage: ... ip6tnl [ mode { ip6ip6 | ipip6 | any } ]\n"
  36                 "                  [ remote ADDR ]\n"
  37                 "                  [ local ADDR ]\n"
  38                 "                  [ dev PHYS_DEV ]\n"
  39                 "                  [ encaplimit ELIM ]\n"
  40                 "                  [ hoplimit HLIM ]\n"
  41                 "                  [ tclass TCLASS ]\n"
  42                 "                  [ flowlabel FLOWLABEL ]\n"
  43                 "                  [ dscp inherit ]\n"
  44                 "                  [ fwmark MARK ]\n"
  45                 "                  [ noencap ]\n"
  46                 "                  [ encap { fou | gue | none } ]\n"
  47                 "                  [ encap-sport PORT ]\n"
  48                 "                  [ encap-dport PORT ]\n"
  49                 "                  [ [no]encap-csum ]\n"
  50                 "                  [ [no]encap-csum6 ]\n"
  51                 "                  [ [no]encap-remcsum ]\n"
  52                 "                  [ external ]\n"
  53                 "\n"
  54                 "Where: ADDR      := IPV6_ADDRESS\n"
  55                 "       ELIM      := { none | 0..255 }(default=%d)\n"
  56                 "       HLIM      := 0..255 (default=%d)\n"
  57                 "       TCLASS    := { 0x0..0xff | inherit }\n"
  58                 "       FLOWLABEL := { 0x0..0xfffff | inherit }\n"
  59                 "       MARK      := { 0x0..0xffffffff | inherit }\n",
  60                 IPV6_DEFAULT_TNL_ENCAP_LIMIT, DEFAULT_TNL_HOP_LIMIT
  61         );
  62 }
  63
  64 static void usage(void) __attribute__((noreturn));
  65 static void usage(void)
  66 {
  67         print_usage(stderr);
  68         exit(-1);
  69 }
  70
  71 static int ip6tunnel_parse_opt(struct link_util *lu, int argc, char **argv,
  72                                struct nlmsghdr *n)
  73 {
  74         struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
  75         struct {
  76                 struct nlmsghdr n;
  77                 struct ifinfomsg i;
  78                 char buf[2048];
  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 rtattr *tb[IFLA_MAX + 1];
  87         struct rtattr *linkinfo[IFLA_INFO_MAX+1];
  88         struct rtattr *iptuninfo[IFLA_IPTUN_MAX + 1];
  89         int len;
  90         struct in6_addr laddr = {};
  91         struct in6_addr raddr = {};
  92         __u8 hop_limit = DEFAULT_TNL_HOP_LIMIT;
  93         __u8 encap_limit = IPV6_DEFAULT_TNL_ENCAP_LIMIT;
  94         __u32 flowinfo = 0;
  95         __u32 flags = 0;
  96         __u32 link = 0;
  97         __u8 proto = 0;
  98         __u16 encaptype = 0;
  99         __u16 encapflags = TUNNEL_ENCAP_FLAG_CSUM6;
 100         __u16 encapsport = 0;
 101         __u16 encapdport = 0;
 102         __u8 metadata = 0;
 103         __u32 fwmark = 0;
 104
 105         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 106                 if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0) {
 107 get_failed:
 108                         fprintf(stderr,
 109                                 "Failed to get existing tunnel info.\n");
 110                         return -1;
 111                 }
 112
 113                 len = req.n.nlmsg_len;
 114                 len -= NLMSG_LENGTH(sizeof(*ifi));
 115                 if (len < 0)
 116                         goto get_failed;
 117
 118                 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);
 119
 120                 if (!tb[IFLA_LINKINFO])
 121                         goto get_failed;
 122
 123                 parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
 124
 125                 if (!linkinfo[IFLA_INFO_DATA])
 126                         goto get_failed;
 127
 128                 parse_rtattr_nested(iptuninfo, IFLA_IPTUN_MAX,
 129                                     linkinfo[IFLA_INFO_DATA]);
 130
 131                 if (iptuninfo[IFLA_IPTUN_LOCAL])
 132                         memcpy(&laddr, RTA_DATA(iptuninfo[IFLA_IPTUN_LOCAL]),
 133                                sizeof(laddr));
 134
 135                 if (iptuninfo[IFLA_IPTUN_REMOTE])
 136                         memcpy(&raddr, RTA_DATA(iptuninfo[IFLA_IPTUN_REMOTE]),
 137                                sizeof(raddr));
 138
 139                 if (iptuninfo[IFLA_IPTUN_TTL])
 140                         hop_limit = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TTL]);
 141
 142                 if (iptuninfo[IFLA_IPTUN_ENCAP_LIMIT])
 143                         encap_limit = rta_getattr_u8(iptuninfo[IFLA_IPTUN_ENCAP_LIMIT]);
 144
 145                 if (iptuninfo[IFLA_IPTUN_FLOWINFO])
 146                         flowinfo = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FLOWINFO]);
 147
 148                 if (iptuninfo[IFLA_IPTUN_FLAGS])
 149                         flags = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FLAGS]);
 150
 151                 if (iptuninfo[IFLA_IPTUN_LINK])
 152                         link = rta_getattr_u32(iptuninfo[IFLA_IPTUN_LINK]);
 153
 154                 if (iptuninfo[IFLA_IPTUN_PROTO])
 155                         proto = rta_getattr_u8(iptuninfo[IFLA_IPTUN_PROTO]);
 156                 if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
 157                         metadata = 1;
 158
 159                 if (iptuninfo[IFLA_IPTUN_FWMARK])
 160                         fwmark = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FWMARK]);
 161         }
 162
 163         while (argc > 0) {
 164                 if (matches(*argv, "mode") == 0) {
 165                         NEXT_ARG();
 166                         if (strcmp(*argv, "ipv6/ipv6") == 0 ||
 167                             strcmp(*argv, "ip6ip6") == 0)
 168                                 proto = IPPROTO_IPV6;
 169                         else if (strcmp(*argv, "ip/ipv6") == 0 ||
 170                                  strcmp(*argv, "ipv4/ipv6") == 0 ||
 171                                  strcmp(*argv, "ipip6") == 0 ||
 172                                  strcmp(*argv, "ip4ip6") == 0)
 173                                 proto = IPPROTO_IPIP;
 174                         else if (strcmp(*argv, "any/ipv6") == 0 ||
 175                                  strcmp(*argv, "any") == 0)
 176                                 proto = 0;
 177                         else
 178                                 invarg("Cannot guess tunnel mode.", *argv);
 179                 } else if (strcmp(*argv, "remote") == 0) {
 180                         inet_prefix addr;
 181
 182                         NEXT_ARG();
 183                         get_prefix(&addr, *argv, preferred_family);
 184                         if (addr.family == AF_UNSPEC)
 185                                 invarg("\"remote\" address family is AF_UNSPEC", *argv);
 186                         memcpy(&raddr, addr.data, addr.bytelen);
 187                 } else if (strcmp(*argv, "local") == 0) {
 188                         inet_prefix addr;
 189
 190                         NEXT_ARG();
 191                         get_prefix(&addr, *argv, preferred_family);
 192                         if (addr.family == AF_UNSPEC)
 193                                 invarg("\"local\" address family is AF_UNSPEC", *argv);
 194                         memcpy(&laddr, addr.data, addr.bytelen);
 195                 } else if (matches(*argv, "dev") == 0) {
 196                         NEXT_ARG();
 197                         link = if_nametoindex(*argv);
 198                         if (link == 0)
 199                                 invarg("\"dev\" is invalid", *argv);
 200                 } else if (strcmp(*argv, "hoplimit") == 0 ||
 201                            strcmp(*argv, "ttl") == 0 ||
 202                            strcmp(*argv, "hlim") == 0) {
 203                         __u8 uval;
 204
 205                         NEXT_ARG();
 206                         if (get_u8(&uval, *argv, 0))
 207                                 invarg("invalid HLIM", *argv);
 208                         hop_limit = uval;
 209                 } else if (strcmp(*argv, "encaplimit") == 0) {
 210                         NEXT_ARG();
 211                         if (strcmp(*argv, "none") == 0) {
 212                                 flags |= IP6_TNL_F_IGN_ENCAP_LIMIT;
 213                         } else {
 214                                 __u8 uval;
 215
 216                                 if (get_u8(&uval, *argv, 0) < -1)
 217                                         invarg("invalid ELIM", *argv);
 218                                 encap_limit = uval;
 219                                 flags &= ~IP6_TNL_F_IGN_ENCAP_LIMIT;
 220                         }
 221                 } else if (strcmp(*argv, "tclass") == 0 ||
 222                            strcmp(*argv, "tc") == 0 ||
 223                            strcmp(*argv, "tos") == 0 ||
 224                            matches(*argv, "dsfield") == 0) {
 225                         __u8 uval;
 226
 227                         NEXT_ARG();
 228                         flowinfo &= ~IP6_FLOWINFO_TCLASS;
 229                         if (strcmp(*argv, "inherit") == 0)
 230                                 flags |= IP6_TNL_F_USE_ORIG_TCLASS;
 231                         else {
 232                                 if (get_u8(&uval, *argv, 16))
 233                                         invarg("invalid TClass", *argv);
 234                                 flowinfo |= htonl((__u32)uval << 20) & IP6_FLOWINFO_TCLASS;
 235                                 flags &= ~IP6_TNL_F_USE_ORIG_TCLASS;
 236                         }
 237                 } else if (strcmp(*argv, "flowlabel") == 0 ||
 238                            strcmp(*argv, "fl") == 0) {
 239                         __u32 uval;
 240
 241                         NEXT_ARG();
 242                         flowinfo &= ~IP6_FLOWINFO_FLOWLABEL;
 243                         if (strcmp(*argv, "inherit") == 0)
 244                                 flags |= IP6_TNL_F_USE_ORIG_FLOWLABEL;
 245                         else {
 246                                 if (get_u32(&uval, *argv, 16))
 247                                         invarg("invalid Flowlabel", *argv);
 248                                 if (uval > 0xFFFFF)
 249                                         invarg("invalid Flowlabel", *argv);
 250                                 flowinfo |= htonl(uval) & IP6_FLOWINFO_FLOWLABEL;
 251                                 flags &= ~IP6_TNL_F_USE_ORIG_FLOWLABEL;
 252                         }
 253                 } else if (strcmp(*argv, "dscp") == 0) {
 254                         NEXT_ARG();
 255                         if (strcmp(*argv, "inherit") != 0)
 256                                 invarg("not inherit", *argv);
 257                         flags |= IP6_TNL_F_RCV_DSCP_COPY;
 258                 } else if (strcmp(*argv, "fwmark") == 0) {
 259                         NEXT_ARG();
 260                         if (strcmp(*argv, "inherit") == 0) {
 261                                 flags |= IP6_TNL_F_USE_ORIG_FWMARK;
 262                                 fwmark = 0;
 263                         } else {
 264                                 if (get_u32(&fwmark, *argv, 0))
 265                                         invarg("invalid fwmark\n", *argv);
 266                                 flags &= ~IP6_TNL_F_USE_ORIG_FWMARK;
 267                         }
 268                 } else if (strcmp(*argv, "noencap") == 0) {
 269                         encaptype = TUNNEL_ENCAP_NONE;
 270                 } else if (strcmp(*argv, "encap") == 0) {
 271                         NEXT_ARG();
 272                         if (strcmp(*argv, "fou") == 0)
 273                                 encaptype = TUNNEL_ENCAP_FOU;
 274                         else if (strcmp(*argv, "gue") == 0)
 275                                 encaptype = TUNNEL_ENCAP_GUE;
 276                         else if (strcmp(*argv, "none") == 0)
 277                                 encaptype = TUNNEL_ENCAP_NONE;
 278                         else
 279                                 invarg("Invalid encap type.", *argv);
 280                 } else if (strcmp(*argv, "encap-sport") == 0) {
 281                         NEXT_ARG();
 282                         if (strcmp(*argv, "auto") == 0)
 283                                 encapsport = 0;
 284                         else if (get_u16(&encapsport, *argv, 0))
 285                                 invarg("Invalid source port.", *argv);
 286                 } else if (strcmp(*argv, "encap-dport") == 0) {
 287                         NEXT_ARG();
 288                         if (get_u16(&encapdport, *argv, 0))
 289                                 invarg("Invalid destination port.", *argv);
 290                 } else if (strcmp(*argv, "encap-csum") == 0) {
 291                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
 292                 } else if (strcmp(*argv, "noencap-csum") == 0) {
 293                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
 294                 } else if (strcmp(*argv, "encap-udp6-csum") == 0) {
 295                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
 296                 } else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
 297                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM6;
 298                 } else if (strcmp(*argv, "encap-remcsum") == 0) {
 299                         encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 300                 } else if (strcmp(*argv, "noencap-remcsum") == 0) {
 301                         encapflags |= ~TUNNEL_ENCAP_FLAG_REMCSUM;
 302                 } else if (strcmp(*argv, "external") == 0) {
 303                         metadata = 1;
 304                 } else
 305                         usage();
 306                 argc--, argv++;
 307         }
 308
 309         addattr8(n, 1024, IFLA_IPTUN_PROTO, proto);
 310         if (metadata) {
 311                 addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
 312                 return 0;
 313         }
 314         addattr_l(n, 1024, IFLA_IPTUN_LOCAL, &laddr, sizeof(laddr));
 315         addattr_l(n, 1024, IFLA_IPTUN_REMOTE, &raddr, sizeof(raddr));
 316         addattr8(n, 1024, IFLA_IPTUN_TTL, hop_limit);
 317         addattr8(n, 1024, IFLA_IPTUN_ENCAP_LIMIT, encap_limit);
 318         addattr32(n, 1024, IFLA_IPTUN_FLOWINFO, flowinfo);
 319         addattr32(n, 1024, IFLA_IPTUN_FLAGS, flags);
 320         addattr32(n, 1024, IFLA_IPTUN_LINK, link);
 321         addattr32(n, 1024, IFLA_IPTUN_FWMARK, fwmark);
 322
 323         addattr16(n, 1024, IFLA_IPTUN_ENCAP_TYPE, encaptype);
 324         addattr16(n, 1024, IFLA_IPTUN_ENCAP_FLAGS, encapflags);
 325         addattr16(n, 1024, IFLA_IPTUN_ENCAP_SPORT, htons(encapsport));
 326         addattr16(n, 1024, IFLA_IPTUN_ENCAP_DPORT, htons(encapdport));
 327
 328         return 0;
 329 }
 330
 331 static void ip6tunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 332 {
 333         char s2[64];
 334         int flags = 0;
 335         __u32 flowinfo = 0;
 336
 337         if (!tb)
 338                 return;
 339
 340         if (tb[IFLA_IPTUN_FLAGS])
 341                 flags = rta_getattr_u32(tb[IFLA_IPTUN_FLAGS]);
 342
 343         if (tb[IFLA_IPTUN_FLOWINFO])
 344                 flowinfo = rta_getattr_u32(tb[IFLA_IPTUN_FLOWINFO]);
 345
 346         if (tb[IFLA_IPTUN_PROTO]) {
 347                 switch (rta_getattr_u8(tb[IFLA_IPTUN_PROTO])) {
 348                 case IPPROTO_IPIP:
 349                         print_string(PRINT_ANY, "proto", "%s ", "ipip6");
 350                         break;
 351                 case IPPROTO_IPV6:
 352                         print_string(PRINT_ANY, "proto", "%s ", "ip6ip6");
 353                         break;
 354                 case 0:
 355                         print_string(PRINT_ANY, "proto", "%s ", "any");
 356                         break;
 357                 }
 358         }
 359
 360         if (tb[IFLA_IPTUN_REMOTE]) {
 361                 print_string(PRINT_ANY,
 362                              "remote",
 363                              "remote %s ",
 364                              rt_addr_n2a_rta(AF_INET6, tb[IFLA_IPTUN_REMOTE]));
 365         }
 366
 367         if (tb[IFLA_IPTUN_LOCAL]) {
 368                 print_string(PRINT_ANY,
 369                              "local",
 370                              "local %s ",
 371                              rt_addr_n2a_rta(AF_INET6, tb[IFLA_IPTUN_LOCAL]));
 372         }
 373
 374         if (tb[IFLA_IPTUN_LINK] && rta_getattr_u32(tb[IFLA_IPTUN_LINK])) {
 375                 unsigned int link = rta_getattr_u32(tb[IFLA_IPTUN_LINK]);
 376                 const char *n = if_indextoname(link, s2);
 377
 378                 if (n)
 379                         print_string(PRINT_ANY, "link", "dev %s ", n);
 380                 else
 381                         print_uint(PRINT_ANY, "link_index", "dev %u ", link);
 382         }
 383
 384         if (flags & IP6_TNL_F_IGN_ENCAP_LIMIT)
 385                 print_bool(PRINT_ANY,
 386                            "ip6_tnl_f_ign_encap_limit",
 387                            "encaplimit none ",
 388                            true);
 389         else if (tb[IFLA_IPTUN_ENCAP_LIMIT])
 390                 print_uint(PRINT_ANY,
 391                            "encap_limit",
 392                            "encaplimit %u ",
 393                            rta_getattr_u8(tb[IFLA_IPTUN_ENCAP_LIMIT]));
 394
 395         if (tb[IFLA_IPTUN_TTL])
 396                 print_uint(PRINT_ANY,
 397                            "ttl",
 398                            "hoplimit %u ",
 399                            rta_getattr_u8(tb[IFLA_IPTUN_TTL]));
 400
 401         if (flags & IP6_TNL_F_USE_ORIG_TCLASS)
 402                 print_bool(PRINT_ANY,
 403                            "ip6_tnl_f_use_orig_tclass",
 404                            "tclass inherit ",
 405                            true);
 406         else if (tb[IFLA_IPTUN_FLOWINFO]) {
 407                 __u32 val = ntohl(flowinfo & IP6_FLOWINFO_TCLASS);
 408
 409                 if (is_json_context()) {
 410                         SPRINT_BUF(b1);
 411
 412                         snprintf(b1, sizeof(b1), "0x%02x", (__u8)(val >> 20));
 413                         print_string(PRINT_JSON, "flowinfo_tclass", NULL, b1);
 414                 } else {
 415                         printf("tclass 0x%02x ", (__u8)(val >> 20));
 416                 }
 417         }
 418
 419         if (flags & IP6_TNL_F_USE_ORIG_FLOWLABEL) {
 420                 print_bool(PRINT_ANY,
 421                            "ip6_tnl_f_use_orig_flowlabel",
 422                            "flowlabel inherit ",
 423                            true);
 424         } else {
 425                 if (is_json_context()) {
 426                         SPRINT_BUF(b1);
 427
 428                         snprintf(b1, sizeof(b1), "0x%05x",
 429                                  ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));
 430                         print_string(PRINT_JSON, "flowlabel", NULL, b1);
 431                 } else {
 432                         printf("flowlabel 0x%05x ",
 433                                ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));
 434                 }
 435         }
 436
 437         if (is_json_context()) {
 438                 SPRINT_BUF(flwinfo);
 439
 440                 snprintf(flwinfo, sizeof(flwinfo), "0x%08x", ntohl(flowinfo));
 441                 print_string(PRINT_JSON, "flowinfo", NULL, flwinfo);
 442         } else {
 443                 printf("(flowinfo 0x%08x) ", ntohl(flowinfo));
 444
 445         }
 446
 447         if (flags & IP6_TNL_F_RCV_DSCP_COPY)
 448                 print_bool(PRINT_ANY,
 449                            "ip6_tnl_f_rcv_dscp_copy",
 450                            "dscp inherit ",
 451                            true);
 452
 453         if (flags & IP6_TNL_F_MIP6_DEV)
 454                 print_bool(PRINT_ANY, "ip6_tnl_f_mip6_dev", "mip6 ", true);
 455
 456         if (flags & IP6_TNL_F_USE_ORIG_FWMARK) {
 457                 print_bool(PRINT_ANY,
 458                            "ip6_tnl_f_use_orig_fwmark",
 459                            "fwmark inherit ",
 460                            true);
 461         } else if (tb[IFLA_IPTUN_FWMARK]) {
 462                 __u32 fwmark = rta_getattr_u32(tb[IFLA_IPTUN_FWMARK]);
 463
 464                 if (fwmark) {
 465                         SPRINT_BUF(b1);
 466
 467                         snprintf(b1, sizeof(b1), "0x%x", fwmark);
 468                         print_string(PRINT_ANY, "fwmark", "fwmark %s ", b1);
 469                 }
 470         }
 471
 472         if (tb[IFLA_IPTUN_ENCAP_TYPE] &&
 473             rta_getattr_u16(tb[IFLA_IPTUN_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
 474                 __u16 type = rta_getattr_u16(tb[IFLA_IPTUN_ENCAP_TYPE]);
 475                 __u16 flags = rta_getattr_u16(tb[IFLA_IPTUN_ENCAP_FLAGS]);
 476                 __u16 sport = rta_getattr_u16(tb[IFLA_IPTUN_ENCAP_SPORT]);
 477                 __u16 dport = rta_getattr_u16(tb[IFLA_IPTUN_ENCAP_DPORT]);
 478
 479                 open_json_object("encap");
 480                 print_string(PRINT_FP, NULL, "encap ", NULL);
 481                 switch (type) {
 482                 case TUNNEL_ENCAP_FOU:
 483                         print_string(PRINT_ANY, "type", "%s ", "fou");
 484                         break;
 485                 case TUNNEL_ENCAP_GUE:
 486                         print_string(PRINT_ANY, "type", "%s ", "gue");
 487                         break;
 488                 default:
 489                         print_null(PRINT_ANY, "type", "unknown ", NULL);
 490                         break;
 491                 }
 492
 493                 if (is_json_context()) {
 494                         print_uint(PRINT_JSON,
 495                                    "sport",
 496                                    NULL,
 497                                    sport ? ntohs(sport) : 0);
 498                         print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));
 499                         print_bool(PRINT_JSON, "csum", NULL,
 500                                    flags & TUNNEL_ENCAP_FLAG_CSUM);
 501                         print_bool(PRINT_JSON, "csum6", NULL,
 502                                    flags & TUNNEL_ENCAP_FLAG_CSUM6);
 503                         print_bool(PRINT_JSON, "remcsum", NULL,
 504                                    flags & TUNNEL_ENCAP_FLAG_REMCSUM);
 505                         close_json_object();
 506                 } else {
 507                         if (sport == 0)
 508                                 fputs("encap-sport auto ", f);
 509                         else
 510                                 fprintf(f, "encap-sport %u", ntohs(sport));
 511
 512                         fprintf(f, "encap-dport %u ", ntohs(dport));
 513
 514                         if (flags & TUNNEL_ENCAP_FLAG_CSUM)
 515                                 fputs("encap-csum ", f);
 516                         else
 517                                 fputs("noencap-csum ", f);
 518
 519                         if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
 520                                 fputs("encap-csum6 ", f);
 521                         else
 522                                 fputs("noencap-csum6 ", f);
 523
 524                         if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
 525                                 fputs("encap-remcsum ", f);
 526                         else
 527                                 fputs("noencap-remcsum ", f);
 528                 }
 529         }
 530 }
 531
 532 static void ip6tunnel_print_help(struct link_util *lu, int argc, char **argv,
 533                                  FILE *f)
 534 {
 535         print_usage(f);
 536 }
 537
 538 struct link_util ip6tnl_link_util = {
 539         .id = "ip6tnl",
 540         .maxattr = IFLA_IPTUN_MAX,
 541         .parse_opt = ip6tunnel_parse_opt,
 542         .print_opt = ip6tunnel_print_opt,
 543         .print_help = ip6tunnel_print_help,
 544 };