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 usage(void) __attribute__((noreturn));
  27 static void usage(void)
  28 {
  29         fprintf(stderr, "Usage: ip link { add | set | change | replace | del } NAME\n");
  30         fprintf(stderr, "          type { gre | gretap } [ remote ADDR ] [ local ADDR ]\n");
  31         fprintf(stderr, "          [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ]\n");
  32         fprintf(stderr, "          [ ttl TTL ] [ tos TOS ] [ [no]pmtudisc ] [ dev PHYS_DEV ]\n");
  33         fprintf(stderr, "\n");
  34         fprintf(stderr, "Where: NAME := STRING\n");
  35         fprintf(stderr, "       ADDR := { IP_ADDRESS | any }\n");
  36         fprintf(stderr, "       TOS  := { NUMBER | inherit }\n");
  37         fprintf(stderr, "       TTL  := { 1..255 | inherit }\n");
  38         fprintf(stderr, "       KEY  := { DOTTED_QUAD | NUMBER }\n");
  39         exit(-1);
  40 }
  41
  42 static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
  43                          struct nlmsghdr *n)
  44 {
  45         struct {
  46                 struct nlmsghdr n;
  47                 struct ifinfomsg i;
  48                 char buf[1024];
  49         } req;
  50         struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
  51         struct rtattr *tb[IFLA_MAX + 1];
  52         struct rtattr *linkinfo[IFLA_INFO_MAX+1];
  53         struct rtattr *greinfo[IFLA_GRE_MAX + 1];
  54         __u16 iflags = 0;
  55         __u16 oflags = 0;
  56         unsigned ikey = 0;
  57         unsigned okey = 0;
  58         unsigned saddr = 0;
  59         unsigned daddr = 0;
  60         unsigned link = 0;
  61         __u8 pmtudisc = 1;
  62         __u8 ttl = 0;
  63         __u8 tos = 0;
  64         int len;
  65
  66         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
  67                 memset(&req, 0, sizeof(req));
  68
  69                 req.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
  70                 req.n.nlmsg_flags = NLM_F_REQUEST;
  71                 req.n.nlmsg_type = RTM_GETLINK;
  72                 req.i.ifi_family = preferred_family;
  73                 req.i.ifi_index = ifi->ifi_index;
  74
  75                 if (rtnl_talk(&rth, &req.n, 0, 0, &req.n, NULL, NULL) < 0) {
  76 get_failed:
  77                         fprintf(stderr,
  78                                 "Failed to get existing tunnel info.\n");
  79                         return -1;
  80                 }
  81
  82                 len = req.n.nlmsg_len;
  83                 len -= NLMSG_LENGTH(sizeof(*ifi));
  84                 if (len < 0)
  85                         goto get_failed;
  86
  87                 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);
  88
  89                 if (!tb[IFLA_LINKINFO])
  90                         goto get_failed;
  91
  92                 parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
  93
  94                 if (!linkinfo[IFLA_INFO_DATA])
  95                         goto get_failed;
  96
  97                 parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
  98                                     linkinfo[IFLA_INFO_DATA]);
  99
 100                 if (greinfo[IFLA_GRE_IKEY])
 101                         ikey = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_IKEY]);
 102
 103                 if (greinfo[IFLA_GRE_OKEY])
 104                         okey = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_OKEY]);
 105
 106                 if (greinfo[IFLA_GRE_IFLAGS])
 107                         iflags = *(__u16 *)RTA_DATA(greinfo[IFLA_GRE_IFLAGS]);
 108
 109                 if (greinfo[IFLA_GRE_OFLAGS])
 110                         oflags = *(__u16 *)RTA_DATA(greinfo[IFLA_GRE_OFLAGS]);
 111
 112                 if (greinfo[IFLA_GRE_LOCAL])
 113                         saddr = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_LOCAL]);
 114
 115                 if (greinfo[IFLA_GRE_REMOTE])
 116                         daddr = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_REMOTE]);
 117
 118                 if (greinfo[IFLA_GRE_PMTUDISC])
 119                         pmtudisc = *(__u8 *)RTA_DATA(
 120                                 greinfo[IFLA_GRE_PMTUDISC]);
 121
 122                 if (greinfo[IFLA_GRE_TTL])
 123                         ttl = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_TTL]);
 124
 125                 if (greinfo[IFLA_GRE_TOS])
 126                         tos = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_TOS]);
 127
 128                 if (greinfo[IFLA_GRE_LINK])
 129                         link = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_LINK]);
 130         }
 131
 132         while (argc > 0) {
 133                 if (!matches(*argv, "key")) {
 134                         unsigned uval;
 135
 136                         NEXT_ARG();
 137                         iflags |= GRE_KEY;
 138                         oflags |= GRE_KEY;
 139                         if (strchr(*argv, '.'))
 140                                 uval = get_addr32(*argv);
 141                         else {
 142                                 if (get_unsigned(&uval, *argv, 0) < 0) {
 143                                         fprintf(stderr,
 144                                                 "Invalid value for \"key\"\n");
 145                                         exit(-1);
 146                                 }
 147                                 uval = htonl(uval);
 148                         }
 149
 150                         ikey = okey = uval;
 151                 } else if (!matches(*argv, "ikey")) {
 152                         unsigned uval;
 153
 154                         NEXT_ARG();
 155                         iflags |= GRE_KEY;
 156                         if (strchr(*argv, '.'))
 157                                 uval = get_addr32(*argv);
 158                         else {
 159                                 if (get_unsigned(&uval, *argv, 0)<0) {
 160                                         fprintf(stderr, "invalid value of \"ikey\"\n");
 161                                         exit(-1);
 162                                 }
 163                                 uval = htonl(uval);
 164                         }
 165                         ikey = uval;
 166                 } else if (!matches(*argv, "okey")) {
 167                         unsigned uval;
 168
 169                         NEXT_ARG();
 170                         oflags |= GRE_KEY;
 171                         if (strchr(*argv, '.'))
 172                                 uval = get_addr32(*argv);
 173                         else {
 174                                 if (get_unsigned(&uval, *argv, 0)<0) {
 175                                         fprintf(stderr, "invalid value of \"okey\"\n");
 176                                         exit(-1);
 177                                 }
 178                                 uval = htonl(uval);
 179                         }
 180                         okey = uval;
 181                 } else if (!matches(*argv, "seq")) {
 182                         iflags |= GRE_SEQ;
 183                         oflags |= GRE_SEQ;
 184                 } else if (!matches(*argv, "iseq")) {
 185                         iflags |= GRE_SEQ;
 186                 } else if (!matches(*argv, "oseq")) {
 187                         oflags |= GRE_SEQ;
 188                 } else if (!matches(*argv, "csum")) {
 189                         iflags |= GRE_CSUM;
 190                         oflags |= GRE_CSUM;
 191                 } else if (!matches(*argv, "icsum")) {
 192                         iflags |= GRE_CSUM;
 193                 } else if (!matches(*argv, "ocsum")) {
 194                         oflags |= GRE_CSUM;
 195                 } else if (!matches(*argv, "nopmtudisc")) {
 196                         pmtudisc = 0;
 197                 } else if (!matches(*argv, "pmtudisc")) {
 198                         pmtudisc = 1;
 199                 } else if (!matches(*argv, "remote")) {
 200                         NEXT_ARG();
 201                         if (strcmp(*argv, "any"))
 202                                 daddr = get_addr32(*argv);
 203                 } else if (!matches(*argv, "local")) {
 204                         NEXT_ARG();
 205                         if (strcmp(*argv, "any"))
 206                                 saddr = get_addr32(*argv);
 207                 } else if (!matches(*argv, "dev")) {
 208                         NEXT_ARG();
 209                         link = if_nametoindex(*argv);
 210                         if (link == 0)
 211                                 exit(-1);
 212                 } else if (!matches(*argv, "ttl") ||
 213                            !matches(*argv, "hoplimit")) {
 214                         unsigned uval;
 215
 216                         NEXT_ARG();
 217                         if (strcmp(*argv, "inherit") != 0) {
 218                                 if (get_unsigned(&uval, *argv, 0))
 219                                         invarg("invalid TTL\n", *argv);
 220                                 if (uval > 255)
 221                                         invarg("TTL must be <= 255\n", *argv);
 222                                 ttl = uval;
 223                         }
 224                 } else if (!matches(*argv, "tos") ||
 225                            !matches(*argv, "tclass") ||
 226                            !matches(*argv, "dsfield")) {
 227                         __u32 uval;
 228
 229                         NEXT_ARG();
 230                         if (strcmp(*argv, "inherit") != 0) {
 231                                 if (rtnl_dsfield_a2n(&uval, *argv))
 232                                         invarg("bad TOS value", *argv);
 233                                 tos = uval;
 234                         } else
 235                                 tos = 1;
 236                 } else
 237                         usage();
 238                 argc--; argv++;
 239         }
 240
 241         if (!ikey && IN_MULTICAST(ntohl(daddr))) {
 242                 ikey = daddr;
 243                 iflags |= GRE_KEY;
 244         }
 245         if (!okey && IN_MULTICAST(ntohl(daddr))) {
 246                 okey = daddr;
 247                 oflags |= GRE_KEY;
 248         }
 249         if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
 250                 fprintf(stderr, "Broadcast tunnel requires a source address.\n");
 251                 return -1;
 252         }
 253
 254         addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
 255         addattr32(n, 1024, IFLA_GRE_OKEY, okey);
 256         addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
 257         addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
 258         addattr_l(n, 1024, IFLA_GRE_LOCAL, &saddr, 4);
 259         addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
 260         addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
 261         if (link)
 262                 addattr32(n, 1024, IFLA_GRE_LINK, link);
 263         addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
 264         addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
 265
 266         return 0;
 267 }
 268
 269 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 270 {
 271         char s1[1024];
 272         char s2[64];
 273         const char *local = "any";
 274         const char *remote = "any";
 275         unsigned iflags = 0;
 276         unsigned oflags = 0;
 277
 278         if (!tb)
 279                 return;
 280
 281         if (tb[IFLA_GRE_REMOTE]) {
 282                 unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_GRE_REMOTE]);
 283
 284                 if (addr)
 285                         remote = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
 286         }
 287
 288         fprintf(f, "remote %s ", remote);
 289
 290         if (tb[IFLA_GRE_LOCAL]) {
 291                 unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_GRE_LOCAL]);
 292
 293                 if (addr)
 294                         local = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
 295         }
 296
 297         fprintf(f, "local %s ", local);
 298
 299         if (tb[IFLA_GRE_LINK] && *(__u32 *)RTA_DATA(tb[IFLA_GRE_LINK])) {
 300                 unsigned link = *(__u32 *)RTA_DATA(tb[IFLA_GRE_LINK]);
 301                 const char *n = if_indextoname(link, s2);
 302
 303                 if (n)
 304                         fprintf(f, "dev %s ", n);
 305                 else
 306                         fprintf(f, "dev %u ", link);
 307         }
 308
 309         if (tb[IFLA_GRE_TTL] && *(__u8 *)RTA_DATA(tb[IFLA_GRE_TTL]))
 310                 fprintf(f, "ttl %d ", *(__u8 *)RTA_DATA(tb[IFLA_GRE_TTL]));
 311         else
 312                 fprintf(f, "ttl inherit ");
 313
 314         if (tb[IFLA_GRE_TOS] && *(__u8 *)RTA_DATA(tb[IFLA_GRE_TOS])) {
 315                 int tos = *(__u8 *)RTA_DATA(tb[IFLA_GRE_TOS]);
 316
 317                 fputs("tos ", f);
 318                 if (tos == 1)
 319                         fputs("inherit ", f);
 320                 else
 321                         fprintf(f, "0x%x ", tos);
 322         }
 323
 324         if (tb[IFLA_GRE_PMTUDISC] &&
 325             !*(__u8 *)RTA_DATA(tb[IFLA_GRE_PMTUDISC]))
 326                 fputs("nopmtudisc ", f);
 327
 328         if (tb[IFLA_GRE_IFLAGS])
 329                 iflags = *(__u16 *)RTA_DATA(tb[IFLA_GRE_IFLAGS]);
 330
 331         if (tb[IFLA_GRE_OFLAGS])
 332                 oflags = *(__u16 *)RTA_DATA(tb[IFLA_GRE_OFLAGS]);
 333
 334         if (iflags & GRE_KEY && tb[IFLA_GRE_IKEY] &&
 335             *(__u32 *)RTA_DATA(tb[IFLA_GRE_IKEY])) {
 336                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
 337                 fprintf(f, "ikey %s ", s2);
 338         }
 339
 340         if (oflags & GRE_KEY && tb[IFLA_GRE_OKEY] &&
 341             *(__u32 *)RTA_DATA(tb[IFLA_GRE_OKEY])) {
 342                 inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
 343                 fprintf(f, "ikey %s ", s2);
 344         }
 345
 346         if (iflags & GRE_SEQ)
 347                 fputs("iseq ", f);
 348         if (oflags & GRE_SEQ)
 349                 fputs("oseq ", f);
 350         if (iflags & GRE_CSUM)
 351                 fputs("icsum ", f);
 352         if (oflags & GRE_CSUM)
 353                 fputs("ocsum ", f);
 354 }
 355
 356 struct link_util gre_link_util = {
 357         .id = "gre",
 358         .maxattr = IFLA_GRE_MAX,
 359         .parse_opt = gre_parse_opt,
 360         .print_opt = gre_print_opt,
 361 };
 362
 363 struct link_util gretap_link_util = {
 364         .id = "gretap",
 365         .maxattr = IFLA_GRE_MAX,
 366         .parse_opt = gre_parse_opt,
 367         .print_opt = gre_print_opt,
 368 };