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;
  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         __be32 ikey = 0;
  85         __be32 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                         return -1;
 108                 }
 109
 110                 len = answer->nlmsg_len;
 111                 len -= NLMSG_LENGTH(sizeof(*ifi));
 112                 if (len < 0)
 113                         goto get_failed;
 114
 115                 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)), len);
 116
 117                 if (!tb[IFLA_LINKINFO])
 118                         goto get_failed;
 119
 120                 parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
 121
 122                 if (!linkinfo[IFLA_INFO_DATA])
 123                         goto get_failed;
 124
 125                 parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
 126                                     linkinfo[IFLA_INFO_DATA]);
 127
 128                 if (greinfo[IFLA_GRE_IKEY])
 129                         ikey = rta_getattr_u32(greinfo[IFLA_GRE_IKEY]);
 130
 131                 if (greinfo[IFLA_GRE_OKEY])
 132                         okey = rta_getattr_u32(greinfo[IFLA_GRE_OKEY]);
 133
 134                 if (greinfo[IFLA_GRE_IFLAGS])
 135                         iflags = rta_getattr_u16(greinfo[IFLA_GRE_IFLAGS]);
 136
 137                 if (greinfo[IFLA_GRE_OFLAGS])
 138                         oflags = rta_getattr_u16(greinfo[IFLA_GRE_OFLAGS]);
 139
 140                 if (greinfo[IFLA_GRE_LOCAL])
 141                         saddr = rta_getattr_u32(greinfo[IFLA_GRE_LOCAL]);
 142
 143                 if (greinfo[IFLA_GRE_REMOTE])
 144                         daddr = rta_getattr_u32(greinfo[IFLA_GRE_REMOTE]);
 145
 146                 if (greinfo[IFLA_GRE_PMTUDISC])
 147                         pmtudisc = rta_getattr_u8(
 148                                 greinfo[IFLA_GRE_PMTUDISC]);
 149
 150                 if (greinfo[IFLA_GRE_TTL])
 151                         ttl = rta_getattr_u8(greinfo[IFLA_GRE_TTL]);
 152
 153                 if (greinfo[IFLA_GRE_TOS])
 154                         tos = rta_getattr_u8(greinfo[IFLA_GRE_TOS]);
 155
 156                 if (greinfo[IFLA_GRE_LINK])
 157                         link = rta_getattr_u32(greinfo[IFLA_GRE_LINK]);
 158
 159                 if (greinfo[IFLA_GRE_ENCAP_TYPE])
 160                         encaptype = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_TYPE]);
 161                 if (greinfo[IFLA_GRE_ENCAP_FLAGS])
 162                         encapflags = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_FLAGS]);
 163                 if (greinfo[IFLA_GRE_ENCAP_SPORT])
 164                         encapsport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_SPORT]);
 165                 if (greinfo[IFLA_GRE_ENCAP_DPORT])
 166                         encapdport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_DPORT]);
 167
 168                 if (greinfo[IFLA_GRE_COLLECT_METADATA])
 169                         metadata = 1;
 170
 171                 if (greinfo[IFLA_GRE_IGNORE_DF])
 172                         ignore_df =
 173                                 !!rta_getattr_u8(greinfo[IFLA_GRE_IGNORE_DF]);
 174
 175                 if (greinfo[IFLA_GRE_FWMARK])
 176                         fwmark = rta_getattr_u32(greinfo[IFLA_GRE_FWMARK]);
 177
 178                 if (greinfo[IFLA_GRE_ERSPAN_INDEX])
 179                         erspan_idx = rta_getattr_u32(greinfo[IFLA_GRE_ERSPAN_INDEX]);
 180
 181                 free(answer);
 182         }
 183
 184         while (argc > 0) {
 185                 if (!matches(*argv, "key")) {
 186                         NEXT_ARG();
 187                         iflags |= GRE_KEY;
 188                         oflags |= GRE_KEY;
 189                         ikey = okey = tnl_parse_key("key", *argv);
 190                 } else if (!matches(*argv, "ikey")) {
 191                         NEXT_ARG();
 192                         iflags |= GRE_KEY;
 193                         ikey = tnl_parse_key("ikey", *argv);
 194                 } else if (!matches(*argv, "okey")) {
 195                         NEXT_ARG();
 196                         oflags |= GRE_KEY;
 197                         okey = tnl_parse_key("okey", *argv);
 198                 } else if (!matches(*argv, "seq")) {
 199                         iflags |= GRE_SEQ;
 200                         oflags |= GRE_SEQ;
 201                 } else if (!matches(*argv, "iseq")) {
 202                         iflags |= GRE_SEQ;
 203                 } else if (!matches(*argv, "oseq")) {
 204                         oflags |= GRE_SEQ;
 205                 } else if (!matches(*argv, "csum")) {
 206                         iflags |= GRE_CSUM;
 207                         oflags |= GRE_CSUM;
 208                 } else if (!matches(*argv, "icsum")) {
 209                         iflags |= GRE_CSUM;
 210                 } else if (!matches(*argv, "ocsum")) {
 211                         oflags |= GRE_CSUM;
 212                 } else if (!matches(*argv, "nopmtudisc")) {
 213                         pmtudisc = 0;
 214                 } else if (!matches(*argv, "pmtudisc")) {
 215                         pmtudisc = 1;
 216                 } else if (!matches(*argv, "remote")) {
 217                         NEXT_ARG();
 218                         daddr = get_addr32(*argv);
 219                 } else if (!matches(*argv, "local")) {
 220                         NEXT_ARG();
 221                         saddr = get_addr32(*argv);
 222                 } else if (!matches(*argv, "dev")) {
 223                         NEXT_ARG();
 224                         link = if_nametoindex(*argv);
 225                         if (link == 0) {
 226                                 fprintf(stderr, "Cannot find device \"%s\"\n",
 227                                         *argv);
 228                                 exit(-1);
 229                         }
 230                 } else if (!matches(*argv, "ttl") ||
 231                            !matches(*argv, "hoplimit")) {
 232                         unsigned int uval;
 233
 234                         NEXT_ARG();
 235                         if (strcmp(*argv, "inherit") != 0) {
 236                                 if (get_unsigned(&uval, *argv, 0))
 237                                         invarg("invalid TTL\n", *argv);
 238                                 if (uval > 255)
 239                                         invarg("TTL must be <= 255\n", *argv);
 240                                 ttl = uval;
 241                         } else
 242                                 ttl = 0;
 243                 } else if (!matches(*argv, "tos") ||
 244                            !matches(*argv, "tclass") ||
 245                            !matches(*argv, "dsfield")) {
 246                         __u32 uval;
 247
 248                         NEXT_ARG();
 249                         if (strcmp(*argv, "inherit") != 0) {
 250                                 if (rtnl_dsfield_a2n(&uval, *argv))
 251                                         invarg("bad TOS value", *argv);
 252                                 tos = uval;
 253                         } else
 254                                 tos = 1;
 255                 } else if (strcmp(*argv, "noencap") == 0) {
 256                         encaptype = TUNNEL_ENCAP_NONE;
 257                 } else if (strcmp(*argv, "encap") == 0) {
 258                         NEXT_ARG();
 259                         if (strcmp(*argv, "fou") == 0)
 260                                 encaptype = TUNNEL_ENCAP_FOU;
 261                         else if (strcmp(*argv, "gue") == 0)
 262                                 encaptype = TUNNEL_ENCAP_GUE;
 263                         else if (strcmp(*argv, "none") == 0)
 264                                 encaptype = TUNNEL_ENCAP_NONE;
 265                         else
 266                                 invarg("Invalid encap type.", *argv);
 267                 } else if (strcmp(*argv, "encap-sport") == 0) {
 268                         NEXT_ARG();
 269                         if (strcmp(*argv, "auto") == 0)
 270                                 encapsport = 0;
 271                         else if (get_u16(&encapsport, *argv, 0))
 272                                 invarg("Invalid source port.", *argv);
 273                 } else if (strcmp(*argv, "encap-dport") == 0) {
 274                         NEXT_ARG();
 275                         if (get_u16(&encapdport, *argv, 0))
 276                                 invarg("Invalid destination port.", *argv);
 277                 } else if (strcmp(*argv, "encap-csum") == 0) {
 278                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
 279                 } else if (strcmp(*argv, "noencap-csum") == 0) {
 280                         encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
 281                 } else if (strcmp(*argv, "encap-udp6-csum") == 0) {
 282                         encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
 283                 } else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
 284                         encapflags |= ~TUNNEL_ENCAP_FLAG_CSUM6;
 285                 } else if (strcmp(*argv, "encap-remcsum") == 0) {
 286                         encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 287                 } else if (strcmp(*argv, "noencap-remcsum") == 0) {
 288                         encapflags |= ~TUNNEL_ENCAP_FLAG_REMCSUM;
 289                 } else if (strcmp(*argv, "external") == 0) {
 290                         metadata = 1;
 291                 } else if (strcmp(*argv, "ignore-df") == 0) {
 292                         ignore_df = 1;
 293                 } else if (strcmp(*argv, "noignore-df") == 0) {
 294                         /*
 295                          *only the lsb is significant, use 2 for presence
 296                          */
 297                         ignore_df = 2;
 298                 } else if (strcmp(*argv, "fwmark") == 0) {
 299                         NEXT_ARG();
 300                         if (get_u32(&fwmark, *argv, 0))
 301                                 invarg("invalid fwmark\n", *argv);
 302                 } else if (strcmp(*argv, "erspan") == 0) {
 303                         NEXT_ARG();
 304                         if (get_u32(&erspan_idx, *argv, 0))
 305                                 invarg("invalid erspan index\n", *argv);
 306                         if (erspan_idx & ~((1<<20) - 1) || erspan_idx == 0)
 307                                 invarg("erspan index must be > 0 and <= 20-bit\n", *argv);
 308                 } else
 309                         usage();
 310                 argc--; argv++;
 311         }
 312
 313         if (!ikey && IN_MULTICAST(ntohl(daddr))) {
 314                 ikey = daddr;
 315                 iflags |= GRE_KEY;
 316         }
 317         if (!okey && IN_MULTICAST(ntohl(daddr))) {
 318                 okey = daddr;
 319                 oflags |= GRE_KEY;
 320         }
 321         if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
 322                 fprintf(stderr, "A broadcast tunnel requires a source address.\n");
 323                 return -1;
 324         }
 325
 326         if (!metadata) {
 327                 addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
 328                 addattr32(n, 1024, IFLA_GRE_OKEY, okey);
 329                 addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
 330                 addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
 331                 addattr_l(n, 1024, IFLA_GRE_LOCAL, &saddr, 4);
 332                 addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
 333                 addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
 334                 if (link)
 335                         addattr32(n, 1024, IFLA_GRE_LINK, link);
 336                 addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
 337                 addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
 338                 addattr32(n, 1024, IFLA_GRE_FWMARK, fwmark);
 339                 if (erspan_idx != 0)
 340                         addattr32(n, 1024, IFLA_GRE_ERSPAN_INDEX, erspan_idx);
 341         } else {
 342                 addattr_l(n, 1024, IFLA_GRE_COLLECT_METADATA, NULL, 0);
 343         }
 344
 345         addattr16(n, 1024, IFLA_GRE_ENCAP_TYPE, encaptype);
 346         addattr16(n, 1024, IFLA_GRE_ENCAP_FLAGS, encapflags);
 347         addattr16(n, 1024, IFLA_GRE_ENCAP_SPORT, htons(encapsport));
 348         addattr16(n, 1024, IFLA_GRE_ENCAP_DPORT, htons(encapdport));
 349
 350         if (ignore_df)
 351                 addattr8(n, 1024, IFLA_GRE_IGNORE_DF, ignore_df & 1);
 352
 353         return 0;
 354 }
 355
 356 static void gre_print_direct_opt(FILE *f, struct rtattr *tb[])
 357 {
 358         char s2[64];
 359         const char *local = "any";
 360         const char *remote = "any";
 361         unsigned int iflags = 0;
 362         unsigned int oflags = 0;
 363
 364         if (tb[IFLA_GRE_REMOTE]) {
 365                 unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_REMOTE]);
 366
 367                 if (addr)
 368                         remote = format_host(AF_INET, 4, &addr);
 369         }
 370
 371         print_string(PRINT_ANY, "remote", "remote %s ", remote);
 372
 373         if (tb[IFLA_GRE_LOCAL]) {
 374                 unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_LOCAL]);
 375
 376                 if (addr)
 377                         local = format_host(AF_INET, 4, &addr);
 378         }
 379
 380         print_string(PRINT_ANY, "local", "local %s ", local);
 381
 382         if (tb[IFLA_GRE_LINK] && rta_getattr_u32(tb[IFLA_GRE_LINK])) {
 383                 unsigned int link = rta_getattr_u32(tb[IFLA_GRE_LINK]);
 384                 const char *n = if_indextoname(link, s2);
 385
 386                 if (n)
 387                         print_string(PRINT_ANY, "link", "dev %s ", n);
 388                 else
 389                         print_uint(PRINT_ANY, "link_index", "dev %u ", link);
 390         }
 391
 392         if (tb[IFLA_GRE_TTL]) {
 393                 __u8 ttl = rta_getattr_u8(tb[IFLA_GRE_TTL]);
 394
 395                 if (ttl)
 396                         print_int(PRINT_ANY, "ttl", "ttl %d ", ttl);
 397                 else
 398                         print_int(PRINT_JSON, "ttl", NULL, ttl);
 399         } else {
 400                 print_string(PRINT_FP, NULL, "ttl %s ", "inherit");
 401         }
 402
 403         if (tb[IFLA_GRE_TOS] && rta_getattr_u8(tb[IFLA_GRE_TOS])) {
 404                 int tos = rta_getattr_u8(tb[IFLA_GRE_TOS]);
 405
 406                 if (is_json_context()) {
 407                         SPRINT_BUF(b1);
 408
 409                         snprintf(b1, sizeof(b1), "0x%x", tos);
 410                         print_string(PRINT_JSON, "tos", NULL, b1);
 411                 } else {
 412                         fputs("tos ", f);
 413                         if (tos == 1)
 414                                 fputs("inherit ", f);
 415                         else
 416                                 fprintf(f, "0x%x ", tos);
 417                 }
 418         }
 419
 420         if (tb[IFLA_GRE_PMTUDISC]) {
 421                 if (!rta_getattr_u8(tb[IFLA_GRE_PMTUDISC]))
 422                         print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);
 423                 else
 424                         print_bool(PRINT_JSON, "pmtudisc", NULL, true);
 425         }
 426
 427         if (tb[IFLA_GRE_IFLAGS])
 428                 iflags = rta_getattr_u16(tb[IFLA_GRE_IFLAGS]);
 429
 430         if (tb[IFLA_GRE_OFLAGS])
 431                 oflags = rta_getattr_u16(tb[IFLA_GRE_OFLAGS]);
 432
 433         if ((iflags & GRE_KEY) && tb[IFLA_GRE_IKEY]) {
 434                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
 435                 print_string(PRINT_ANY, "ikey", "ikey %s ", s2);
 436         }
 437
 438         if ((oflags & GRE_KEY) && tb[IFLA_GRE_OKEY]) {
 439                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
 440                 print_string(PRINT_ANY, "okey", "okey %s ", s2);
 441         }
 442
 443         if (iflags & GRE_SEQ)
 444                 print_bool(PRINT_ANY, "iseq", "iseq ", true);
 445         if (oflags & GRE_SEQ)
 446                 print_bool(PRINT_ANY, "oseq", "oseq ", true);
 447         if (iflags & GRE_CSUM)
 448                 print_bool(PRINT_ANY, "icsum", "icsum ", true);
 449         if (oflags & GRE_CSUM)
 450                 print_bool(PRINT_ANY, "ocsum", "ocsum ", true);
 451
 452         if (tb[IFLA_GRE_FWMARK]) {
 453                 __u32 fwmark = rta_getattr_u32(tb[IFLA_GRE_FWMARK]);
 454
 455                 if (fwmark) {
 456                         snprintf(s2, sizeof(s2), "0x%x", fwmark);
 457
 458                         print_string(PRINT_ANY, "fwmark", "fwmark %s ", s2);
 459                 }
 460         }
 461 }
 462
 463 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 464 {
 465         if (!tb)
 466                 return;
 467
 468         if (!tb[IFLA_GRE_COLLECT_METADATA])
 469                 gre_print_direct_opt(f, tb);
 470         else
 471                 print_bool(PRINT_ANY, "external", "external ", true);
 472
 473         if (tb[IFLA_GRE_IGNORE_DF] && rta_getattr_u8(tb[IFLA_GRE_IGNORE_DF]))
 474                 print_bool(PRINT_ANY, "ignore_df", "ignore-df ", true);
 475
 476         if (tb[IFLA_GRE_ERSPAN_INDEX]) {
 477                 __u32 erspan_idx = rta_getattr_u32(tb[IFLA_GRE_ERSPAN_INDEX]);
 478
 479                 fprintf(f, "erspan_index %u ", erspan_idx);
 480         }
 481
 482         if (tb[IFLA_GRE_ENCAP_TYPE] &&
 483             rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
 484                 __u16 type = rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]);
 485                 __u16 flags = rta_getattr_u16(tb[IFLA_GRE_ENCAP_FLAGS]);
 486                 __u16 sport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_SPORT]);
 487                 __u16 dport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_DPORT]);
 488
 489
 490                 open_json_object("encap");
 491                 print_string(PRINT_FP, NULL, "encap ", NULL);
 492
 493                 switch (type) {
 494                 case TUNNEL_ENCAP_FOU:
 495                         print_string(PRINT_ANY, "type", "%s ", "fou");
 496                         break;
 497                 case TUNNEL_ENCAP_GUE:
 498                         print_string(PRINT_ANY, "type", "%s ", "gue");
 499                         break;
 500                 default:
 501                         print_null(PRINT_ANY, "type", "%s ", "unknown");
 502                         break;
 503                 }
 504
 505                 if (is_json_context()) {
 506                         print_uint(PRINT_JSON,
 507                                    "sport",
 508                                    NULL,
 509                                    sport ? ntohs(sport) : 0);
 510                         print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));
 511
 512                         print_bool(PRINT_JSON,
 513                                    "csum",
 514                                    NULL,
 515                                    flags & TUNNEL_ENCAP_FLAG_CSUM);
 516
 517                         print_bool(PRINT_JSON,
 518                                    "csum6",
 519                                    NULL,
 520                                    flags & TUNNEL_ENCAP_FLAG_CSUM6);
 521
 522                         print_bool(PRINT_JSON,
 523                                    "remcsum",
 524                                    NULL,
 525                                    flags & TUNNEL_ENCAP_FLAG_REMCSUM);
 526
 527                         close_json_object();
 528                 } else {
 529                         if (sport == 0)
 530                                 fputs("encap-sport auto ", f);
 531                         else
 532                                 fprintf(f, "encap-sport %u", ntohs(sport));
 533
 534                         fprintf(f, "encap-dport %u ", ntohs(dport));
 535
 536                         if (flags & TUNNEL_ENCAP_FLAG_CSUM)
 537                                 fputs("encap-csum ", f);
 538                         else
 539                                 fputs("noencap-csum ", f);
 540
 541                         if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
 542                                 fputs("encap-csum6 ", f);
 543                         else
 544                                 fputs("noencap-csum6 ", f);
 545
 546                         if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
 547                                 fputs("encap-remcsum ", f);
 548                         else
 549                                 fputs("noencap-remcsum ", f);
 550                 }
 551         }
 552 }
 553
 554 static void gre_print_help(struct link_util *lu, int argc, char **argv,
 555                            FILE *f)
 556 {
 557         print_usage(f);
 558 }
 559
 560 struct link_util gre_link_util = {
 561         .id = "gre",
 562         .maxattr = IFLA_GRE_MAX,
 563         .parse_opt = gre_parse_opt,
 564         .print_opt = gre_print_opt,
 565         .print_help = gre_print_help,
 566 };
 567
 568 struct link_util gretap_link_util = {
 569         .id = "gretap",
 570         .maxattr = IFLA_GRE_MAX,
 571         .parse_opt = gre_parse_opt,
 572         .print_opt = gre_print_opt,
 573         .print_help = gre_print_help,
 574 };
 575
 576 struct link_util erspan_link_util = {
 577         .id = "erspan",
 578         .maxattr = IFLA_GRE_MAX,
 579         .parse_opt = gre_parse_opt,
 580         .print_opt = gre_print_opt,
 581         .print_help = gre_print_help,
 582 };