ip/link_gre.c

   1 /*
   2  * link_gre.c   gre 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:     Herbert Xu <herbert@gondor.apana.org.au>
  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 "rt_names.h"
  22 #include "utils.h"
  23 #include "ip_common.h"
  24 #include "tunnel.h"
  25
  26 static void print_usage(FILE *f)
  27 {
  28         fprintf(f,
  29                 "Usage: ... { gre | gretap | erspan } [ remote ADDR ]\n"
  30                 "                            [ local ADDR ]\n"
  31                 "                            [ [i|o]seq ]\n"
  32                 "                            [ [i|o]key KEY ]\n"
  33                 "                            [ [i|o]csum ]\n"
  34                 "                            [ ttl TTL ]\n"
  35                 "                            [ tos TOS ]\n"
  36                 "                            [ [no]pmtudisc ]\n"
  37                 "                            [ [no]ignore-df ]\n"
  38                 "                            [ dev PHYS_DEV ]\n"
  39                 "                            [ noencap ]\n"
  40                 "                            [ encap { fou | gue | none } ]\n"
  41                 "                            [ encap-sport PORT ]\n"
  42                 "                            [ encap-dport PORT ]\n"
  43                 "                            [ [no]encap-csum ]\n"
  44                 "                            [ [no]encap-csum6 ]\n"
  45                 "                            [ [no]encap-remcsum ]\n"
  46                 "                            [ fwmark MARK ]\n"
  47                 "                            [ erspan IDX ]\n"
  48                 "\n"
  49                 "Where: ADDR := { IP_ADDRESS | any }\n"
  50                 "       TOS  := { NUMBER | inherit }\n"
  51                 "       TTL  := { 1..255 | inherit }\n"
  52                 "       KEY  := { DOTTED_QUAD | NUMBER }\n"
  53                 "       MARK := { 0x0..0xffffffff }\n"
  54         );
  55 }
  56
  57 static void usage(void) __attribute__((noreturn));
  58 static void usage(void)
  59 {
  60         print_usage(stderr);
  61         exit(-1);
  62 }
  63
  64 static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
  65                          struct nlmsghdr *n)
  66 {
  67         struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
  68         struct {
  69                 struct nlmsghdr n;
  70                 struct ifinfomsg i;
  71         } req = {
  72                 .n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)),
  73                 .n.nlmsg_flags = NLM_F_REQUEST,
  74                 .n.nlmsg_type = RTM_GETLINK,
  75                 .i.ifi_family = preferred_family,
  76                 .i.ifi_index = ifi->ifi_index,
  77         };
  78         struct nlmsghdr *answer = NULL;
  79         struct rtattr *tb[IFLA_MAX + 1];
  80         struct rtattr *linkinfo[IFLA_INFO_MAX+1];
  81         struct rtattr *greinfo[IFLA_GRE_MAX + 1];
  82         __u16 iflags = 0;
  83         __u16 oflags = 0;
  84         unsigned int ikey = 0;
  85         unsigned int okey = 0;
  86         unsigned int saddr = 0;
  87         unsigned int daddr = 0;
  88         unsigned int link = 0;
  89         __u8 pmtudisc = 1;
  90         __u8 ttl = 0;
  91         __u8 tos = 0;
  92         int len;
  93         __u16 encaptype = 0;
  94         __u16 encapflags = 0;
  95         __u16 encapsport = 0;
  96         __u16 encapdport = 0;
  97         __u8 metadata = 0;
  98         __u8 ignore_df = 0;
  99         __u32 fwmark = 0;
 100         __u32 erspan_idx = 0;
 101
 102         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 103                 if (rtnl_talk(&rth, &req.n, &answer) < 0) {
 104 get_failed:
 105                         fprintf(stderr,
 106                                 "Failed to get existing tunnel info.\n");
 107                         free(answer);
 108                         return -1;
 109                 }
 110
 111                 len = answer->nlmsg_len;
 112                 len -= NLMSG_LENGTH(sizeof(*ifi));
 113                 if (len < 0)
 114                         goto get_failed;
 115
 116                 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)), len);
 117
 118                 if (!tb[IFLA_LINKINFO])
 119                         goto get_failed;
 120
 121                 parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
 122
 123                 if (!linkinfo[IFLA_INFO_DATA])
 124                         goto get_failed;
 125
 126                 parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
 127                                     linkinfo[IFLA_INFO_DATA]);
 128
 129                 if (greinfo[IFLA_GRE_IKEY])
 130                         ikey = rta_getattr_u32(greinfo[IFLA_GRE_IKEY]);
 131
 132                 if (greinfo[IFLA_GRE_OKEY])
 133                         okey = rta_getattr_u32(greinfo[IFLA_GRE_OKEY]);
 134
 135                 if (greinfo[IFLA_GRE_IFLAGS])
 136                         iflags = rta_getattr_u16(greinfo[IFLA_GRE_IFLAGS]);
 137
 138                 if (greinfo[IFLA_GRE_OFLAGS])
 139                         oflags = rta_getattr_u16(greinfo[IFLA_GRE_OFLAGS]);
 140
 141                 if (greinfo[IFLA_GRE_LOCAL])
 142                         saddr = rta_getattr_u32(greinfo[IFLA_GRE_LOCAL]);
 143
 144                 if (greinfo[IFLA_GRE_REMOTE])
 145                         daddr = rta_getattr_u32(greinfo[IFLA_GRE_REMOTE]);
 146
 147                 if (greinfo[IFLA_GRE_PMTUDISC])
 148                         pmtudisc = rta_getattr_u8(
 149                                 greinfo[IFLA_GRE_PMTUDISC]);
 150
 151                 if (greinfo[IFLA_GRE_TTL])
 152                         ttl = rta_getattr_u8(greinfo[IFLA_GRE_TTL]);
 153
 154                 if (greinfo[IFLA_GRE_TOS])
 155                         tos = rta_getattr_u8(greinfo[IFLA_GRE_TOS]);
 156
 157                 if (greinfo[IFLA_GRE_LINK])
 158                         link = rta_getattr_u8(greinfo[IFLA_GRE_LINK]);
 159
 160                 if (greinfo[IFLA_GRE_ENCAP_TYPE])
 161                         encaptype = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_TYPE]);
 162                 if (greinfo[IFLA_GRE_ENCAP_FLAGS])
 163                         encapflags = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_FLAGS]);
 164                 if (greinfo[IFLA_GRE_ENCAP_SPORT])
 165                         encapsport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_SPORT]);
 166                 if (greinfo[IFLA_GRE_ENCAP_DPORT])
 167                         encapdport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_DPORT]);
 168
 169                 if (greinfo[IFLA_GRE_COLLECT_METADATA])
 170                         metadata = 1;
 171
 172                 if (greinfo[IFLA_GRE_IGNORE_DF])
 173                         ignore_df =
 174                                 !!rta_getattr_u8(greinfo[IFLA_GRE_IGNORE_DF]);
 175
 176                 if (greinfo[IFLA_GRE_FWMARK])
 177                         fwmark = rta_getattr_u32(greinfo[IFLA_GRE_FWMARK]);
 178
 179                 if (greinfo[IFLA_GRE_ERSPAN_INDEX])
 180                         erspan_idx = rta_getattr_u32(greinfo[IFLA_GRE_ERSPAN_INDEX]);
 181
 182                 free(answer);
 183         }
 184
 185         while (argc > 0) {
 186                 if (!matches(*argv, "key")) {
 187                         unsigned int uval;
 188
 189                         NEXT_ARG();
 190                         iflags |= GRE_KEY;
 191                         oflags |= GRE_KEY;
 192                         if (strchr(*argv, '.'))
 193                                 uval = get_addr32(*argv);
 194                         else {
 195                                 if (get_unsigned(&uval, *argv, 0) < 0) {
 196                                         fprintf(stderr,
 197                                                 "Invalid value for \"key\": \"%s\"; it should be an unsigned integer\n", *argv);
 198                                         exit(-1);
 199                                 }
 200                                 uval = htonl(uval);
 201                         }
 202
 203                         ikey = okey = uval;
 204                 } else if (!matches(*argv, "ikey")) {
 205                         unsigned int uval;
 206
 207                         NEXT_ARG();
 208                         iflags |= GRE_KEY;
 209                         if (strchr(*argv, '.'))
 210                                 uval = get_addr32(*argv);
 211                         else {
 212                                 if (get_unsigned(&uval, *argv, 0) < 0) {
 213                                         fprintf(stderr, "invalid value for \"ikey\": \"%s\"; it should be an unsigned integer\n", *argv);
 214                                         exit(-1);
 215                                 }
 216                                 uval = htonl(uval);
 217                         }
 218                         ikey = uval;
 219                 } else if (!matches(*argv, "okey")) {
 220                         unsigned int uval;
 221
 222                         NEXT_ARG();
 223                         oflags |= GRE_KEY;
 224                         if (strchr(*argv, '.'))
 225                                 uval = get_addr32(*argv);
 226                         else {
 227                                 if (get_unsigned(&uval, *argv, 0) < 0) {
 228                                         fprintf(stderr, "invalid value for \"okey\": \"%s\"; it should be an unsigned integer\n", *argv);
 229                                         exit(-1);
 230                                 }
 231                                 uval = htonl(uval);
 232                         }
 233                         okey = uval;
 234                 } else if (!matches(*argv, "seq")) {
 235                         iflags |= GRE_SEQ;
 236                         oflags |= GRE_SEQ;
 237                 } else if (!matches(*argv, "iseq")) {
 238                         iflags |= GRE_SEQ;
 239                 } else if (!matches(*argv, "oseq")) {
 240                         oflags |= GRE_SEQ;
 241                 } else if (!matches(*argv, "csum")) {
 242                         iflags |= GRE_CSUM;
 243                         oflags |= GRE_CSUM;
 244                 } else if (!matches(*argv, "icsum")) {
 245                         iflags |= GRE_CSUM;
 246                 } else if (!matches(*argv, "ocsum")) {
 247                         oflags |= GRE_CSUM;
 248                 } else if (!matches(*argv, "nopmtudisc")) {
 249                         pmtudisc = 0;
 250                 } else if (!matches(*argv, "pmtudisc")) {
 251                         pmtudisc = 1;
 252                 } else if (!matches(*argv, "remote")) {
 253                         NEXT_ARG();
 254                         daddr = get_addr32(*argv);
 255                 } else if (!matches(*argv, "local")) {
 256                         NEXT_ARG();
 257                         saddr = get_addr32(*argv);
 258                 } else if (!matches(*argv, "dev")) {
 259                         NEXT_ARG();
 260                         link = if_nametoindex(*argv);
 261                         if (link == 0) {
 262                                 fprintf(stderr, "Cannot find device \"%s\"\n",
 263                                         *argv);
 264                                 exit(-1);
 265                         }
 266                 } else if (!matches(*argv, "ttl") ||
 267                            !matches(*argv, "hoplimit")) {
 268                         unsigned int uval;
 269
 270                         NEXT_ARG();
 271                         if (strcmp(*argv, "inherit") != 0) {
 272                                 if (get_unsigned(&uval, *argv, 0))
 273                                         invarg("invalid TTL\n", *argv);
 274                                 if (uval > 255)
 275                                         invarg("TTL must be <= 255\n", *argv);
 276                                 ttl = uval;
 277                         } else
 278                                 ttl = 0;
 279                 } else if (!matches(*argv, "tos") ||
 280                            !matches(*argv, "tclass") ||
 281                            !matches(*argv, "dsfield")) {
 282                         __u32 uval;
 283
 284                         NEXT_ARG();
 285                         if (strcmp(*argv, "inherit") != 0) {
 286                                 if (rtnl_dsfield_a2n(&uval, *argv))
 287                                         invarg("bad TOS value", *argv);
 288                                 tos = uval;
 289                         } else
 290                                 tos = 1;
 291                 } else if (strcmp(*argv, "noencap") == 0) {
 292                         encaptype = TUNNEL_ENCAP_NONE;
 293                 } else if (strcmp(*argv, "encap") == 0) {
 294                         NEXT_ARG();
 295                         if (strcmp(*argv, "fou") == 0)
 296                                 encaptype = TUNNEL_ENCAP_FOU;
 297                         else if (strcmp(*argv, "gue") == 0)
 298                                 encaptype = TUNNEL_ENCAP_GUE;
 299                         else if (strcmp(*argv, "none") == 0)
 300                                 encaptype = TUNNEL_ENCAP_NONE;
 301                         else
 302                                 invarg("Invalid encap type.", *argv);
 303                 } else if (strcmp(*argv, "encap-sport") == 0) {
 304                         NEXT_ARG();
 305                         if (strcmp(*argv, "auto") == 0)
 306                                 encapsport = 0;
 307                         else if (get_u16(&encapsport, *argv, 0))
 308                                 invarg("Invalid source port.", *argv);
 309                 } else if (strcmp(*argv, "encap-dport") == 0) {
 310                         NEXT_ARG();
 311                         if (get_u16(&encapdport, *argv, 0))
 312                                 invarg("Invalid destination port.", *argv);
 313                 } else if (strcmp(*argv, "encap-csum") == 0) {
 314                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
 315                 } else if (strcmp(*argv, "noencap-csum") == 0) {
 316                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
 317                 } else if (strcmp(*argv, "encap-udp6-csum") == 0) {
 318                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
 319                 } else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
 320                         encapflags |= ~TUNNEL_ENCAP_FLAG_CSUM6;
 321                 } else if (strcmp(*argv, "encap-remcsum") == 0) {
 322                         encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 323                 } else if (strcmp(*argv, "noencap-remcsum") == 0) {
 324                         encapflags |= ~TUNNEL_ENCAP_FLAG_REMCSUM;
 325                 } else if (strcmp(*argv, "external") == 0) {
 326                         metadata = 1;
 327                 } else if (strcmp(*argv, "ignore-df") == 0) {
 328                         ignore_df = 1;
 329                 } else if (strcmp(*argv, "noignore-df") == 0) {
 330                         /*
 331                          *only the lsb is significant, use 2 for presence
 332                          */
 333                         ignore_df = 2;
 334                 } else if (strcmp(*argv, "fwmark") == 0) {
 335                         NEXT_ARG();
 336                         if (get_u32(&fwmark, *argv, 0))
 337                                 invarg("invalid fwmark\n", *argv);
 338                 } else if (strcmp(*argv, "erspan") == 0) {
 339                         NEXT_ARG();
 340                         if (get_u32(&erspan_idx, *argv, 0))
 341                                 invarg("invalid erspan index\n", *argv);
 342                         if (erspan_idx & ~((1<<20) - 1) || erspan_idx == 0)
 343                                 invarg("erspan index must be > 0 and <= 20-bit\n", *argv);
 344                 } else
 345                         usage();
 346                 argc--; argv++;
 347         }
 348
 349         if (!ikey && IN_MULTICAST(ntohl(daddr))) {
 350                 ikey = daddr;
 351                 iflags |= GRE_KEY;
 352         }
 353         if (!okey && IN_MULTICAST(ntohl(daddr))) {
 354                 okey = daddr;
 355                 oflags |= GRE_KEY;
 356         }
 357         if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
 358                 fprintf(stderr, "A broadcast tunnel requires a source address.\n");
 359                 return -1;
 360         }
 361
 362         if (!metadata) {
 363                 addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
 364                 addattr32(n, 1024, IFLA_GRE_OKEY, okey);
 365                 addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
 366                 addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
 367                 addattr_l(n, 1024, IFLA_GRE_LOCAL, &saddr, 4);
 368                 addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
 369                 addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
 370                 if (link)
 371                         addattr32(n, 1024, IFLA_GRE_LINK, link);
 372                 addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
 373                 addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
 374                 addattr32(n, 1024, IFLA_GRE_FWMARK, fwmark);
 375                 if (erspan_idx != 0)
 376                         addattr32(n, 1024, IFLA_GRE_ERSPAN_INDEX, erspan_idx);
 377         } else {
 378                 addattr_l(n, 1024, IFLA_GRE_COLLECT_METADATA, NULL, 0);
 379         }
 380
 381         addattr16(n, 1024, IFLA_GRE_ENCAP_TYPE, encaptype);
 382         addattr16(n, 1024, IFLA_GRE_ENCAP_FLAGS, encapflags);
 383         addattr16(n, 1024, IFLA_GRE_ENCAP_SPORT, htons(encapsport));
 384         addattr16(n, 1024, IFLA_GRE_ENCAP_DPORT, htons(encapdport));
 385
 386         if (ignore_df)
 387                 addattr8(n, 1024, IFLA_GRE_IGNORE_DF, ignore_df & 1);
 388
 389         return 0;
 390 }
 391
 392 static void gre_print_direct_opt(FILE *f, struct rtattr *tb[])
 393 {
 394         char s2[64];
 395         const char *local = "any";
 396         const char *remote = "any";
 397         unsigned int iflags = 0;
 398         unsigned int oflags = 0;
 399
 400         if (tb[IFLA_GRE_REMOTE]) {
 401                 unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_REMOTE]);
 402
 403                 if (addr)
 404                         remote = format_host(AF_INET, 4, &addr);
 405         }
 406
 407         print_string(PRINT_ANY, "remote", "remote %s ", remote);
 408
 409         if (tb[IFLA_GRE_LOCAL]) {
 410                 unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_LOCAL]);
 411
 412                 if (addr)
 413                         local = format_host(AF_INET, 4, &addr);
 414         }
 415
 416         print_string(PRINT_ANY, "local", "local %s ", local);
 417
 418         if (tb[IFLA_GRE_LINK] && rta_getattr_u32(tb[IFLA_GRE_LINK])) {
 419                 unsigned int link = rta_getattr_u32(tb[IFLA_GRE_LINK]);
 420                 const char *n = if_indextoname(link, s2);
 421
 422                 if (n)
 423                         print_string(PRINT_ANY, "link", "dev %s ", n);
 424                 else
 425                         print_uint(PRINT_ANY, "link_index", "dev %u ", link);
 426         }
 427
 428         if (tb[IFLA_GRE_TTL]) {
 429                 __u8 ttl = rta_getattr_u8(tb[IFLA_GRE_TTL]);
 430
 431                 if (ttl)
 432                         print_int(PRINT_ANY, "ttl", "ttl %d ", ttl);
 433                 else
 434                         print_int(PRINT_JSON, "ttl", NULL, ttl);
 435         } else {
 436                 print_string(PRINT_FP, NULL, "ttl %s ", "inherit");
 437         }
 438
 439         if (tb[IFLA_GRE_TOS] && rta_getattr_u8(tb[IFLA_GRE_TOS])) {
 440                 int tos = rta_getattr_u8(tb[IFLA_GRE_TOS]);
 441
 442                 if (is_json_context()) {
 443                         SPRINT_BUF(b1);
 444
 445                         snprintf(b1, sizeof(b1), "0x%x", tos);
 446                         print_string(PRINT_JSON, "tos", NULL, b1);
 447                 } else {
 448                         fputs("tos ", f);
 449                         if (tos == 1)
 450                                 fputs("inherit ", f);
 451                         else
 452                                 fprintf(f, "0x%x ", tos);
 453                 }
 454         }
 455
 456         if (tb[IFLA_GRE_PMTUDISC]) {
 457                 if (!rta_getattr_u8(tb[IFLA_GRE_PMTUDISC]))
 458                         print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);
 459                 else
 460                         print_bool(PRINT_JSON, "pmtudisc", NULL, true);
 461         }
 462
 463         if (tb[IFLA_GRE_IFLAGS])
 464                 iflags = rta_getattr_u16(tb[IFLA_GRE_IFLAGS]);
 465
 466         if (tb[IFLA_GRE_OFLAGS])
 467                 oflags = rta_getattr_u16(tb[IFLA_GRE_OFLAGS]);
 468
 469         if ((iflags & GRE_KEY) && tb[IFLA_GRE_IKEY]) {
 470                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
 471                 print_string(PRINT_ANY, "ikey", "ikey %s ", s2);
 472         }
 473
 474         if ((oflags & GRE_KEY) && tb[IFLA_GRE_OKEY]) {
 475                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
 476                 print_string(PRINT_ANY, "okey", "okey %s ", s2);
 477         }
 478
 479         if (iflags & GRE_SEQ)
 480                 print_bool(PRINT_ANY, "iseq", "iseq ", true);
 481         if (oflags & GRE_SEQ)
 482                 print_bool(PRINT_ANY, "oseq", "oseq ", true);
 483         if (iflags & GRE_CSUM)
 484                 print_bool(PRINT_ANY, "icsum", "icsum ", true);
 485         if (oflags & GRE_CSUM)
 486                 print_bool(PRINT_ANY, "ocsum", "ocsum ", true);
 487
 488         if (tb[IFLA_GRE_FWMARK]) {
 489                 __u32 fwmark = rta_getattr_u32(tb[IFLA_GRE_FWMARK]);
 490
 491                 if (fwmark) {
 492                         snprintf(s2, sizeof(s2), "0x%x", fwmark);
 493
 494                         print_string(PRINT_ANY, "fwmark", "fwmark %s ", s2);
 495                 }
 496         }
 497 }
 498
 499 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 500 {
 501         if (!tb)
 502                 return;
 503
 504         if (!tb[IFLA_GRE_COLLECT_METADATA])
 505                 gre_print_direct_opt(f, tb);
 506         else
 507                 print_bool(PRINT_ANY, "external", "external ", true);
 508
 509         if (tb[IFLA_GRE_IGNORE_DF] && rta_getattr_u8(tb[IFLA_GRE_IGNORE_DF]))
 510                 print_bool(PRINT_ANY, "ignore_df", "ignore-df ", true);
 511
 512         if (tb[IFLA_GRE_ERSPAN_INDEX]) {
 513                 __u32 erspan_idx = rta_getattr_u32(tb[IFLA_GRE_ERSPAN_INDEX]);
 514
 515                 fprintf(f, "erspan_index %u ", erspan_idx);
 516         }
 517
 518         if (tb[IFLA_GRE_ENCAP_TYPE] &&
 519             rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
 520                 __u16 type = rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]);
 521                 __u16 flags = rta_getattr_u16(tb[IFLA_GRE_ENCAP_FLAGS]);
 522                 __u16 sport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_SPORT]);
 523                 __u16 dport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_DPORT]);
 524
 525
 526                 open_json_object("encap");
 527                 print_string(PRINT_FP, NULL, "encap ", NULL);
 528
 529                 switch (type) {
 530                 case TUNNEL_ENCAP_FOU:
 531                         print_string(PRINT_ANY, "type", "%s ", "fou");
 532                         break;
 533                 case TUNNEL_ENCAP_GUE:
 534                         print_string(PRINT_ANY, "type", "%s ", "gue");
 535                         break;
 536                 default:
 537                         print_null(PRINT_ANY, "type", "%s ", "unknown");
 538                         break;
 539                 }
 540
 541                 if (is_json_context()) {
 542                         print_uint(PRINT_JSON,
 543                                    "sport",
 544                                    NULL,
 545                                    sport ? ntohs(sport) : 0);
 546                         print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));
 547
 548                         print_bool(PRINT_JSON,
 549                                    "csum",
 550                                    NULL,
 551                                    flags & TUNNEL_ENCAP_FLAG_CSUM);
 552
 553                         print_bool(PRINT_JSON,
 554                                    "csum6",
 555                                    NULL,
 556                                    flags & TUNNEL_ENCAP_FLAG_CSUM6);
 557
 558                         print_bool(PRINT_JSON,
 559                                    "remcsum",
 560                                    NULL,
 561                                    flags & TUNNEL_ENCAP_FLAG_REMCSUM);
 562
 563                         close_json_object();
 564                 } else {
 565                         if (sport == 0)
 566                                 fputs("encap-sport auto ", f);
 567                         else
 568                                 fprintf(f, "encap-sport %u", ntohs(sport));
 569
 570                         fprintf(f, "encap-dport %u ", ntohs(dport));
 571
 572                         if (flags & TUNNEL_ENCAP_FLAG_CSUM)
 573                                 fputs("encap-csum ", f);
 574                         else
 575                                 fputs("noencap-csum ", f);
 576
 577                         if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
 578                                 fputs("encap-csum6 ", f);
 579                         else
 580                                 fputs("noencap-csum6 ", f);
 581
 582                         if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
 583                                 fputs("encap-remcsum ", f);
 584                         else
 585                                 fputs("noencap-remcsum ", f);
 586                 }
 587         }
 588 }
 589
 590 static void gre_print_help(struct link_util *lu, int argc, char **argv,
 591                            FILE *f)
 592 {
 593         print_usage(f);
 594 }
 595
 596 struct link_util gre_link_util = {
 597         .id = "gre",
 598         .maxattr = IFLA_GRE_MAX,
 599         .parse_opt = gre_parse_opt,
 600         .print_opt = gre_print_opt,
 601         .print_help = gre_print_help,
 602 };
 603
 604 struct link_util gretap_link_util = {
 605         .id = "gretap",
 606         .maxattr = IFLA_GRE_MAX,
 607         .parse_opt = gre_parse_opt,
 608         .print_opt = gre_print_opt,
 609         .print_help = gre_print_help,
 610 };
 611
 612 struct link_util erspan_link_util = {
 613         .id = "erspan",
 614         .maxattr = IFLA_GRE_MAX,
 615         .parse_opt = gre_parse_opt,
 616         .print_opt = gre_print_opt,
 617         .print_help = gre_print_help,
 618 };