networking/libiproute/iptunnel.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * iptunnel.c          "ip tunnel"
   4  *
   5  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   6  *
   7  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   8  *
   9  *
  10  * Changes:
  11  *
  12  * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
  13  * Rani Assaf <rani@magic.metawire.com> 980930: do not allow key for ipip/sit
  14  * Phil Karn <karn@ka9q.ampr.org>       990408: "pmtudisc" flag
  15  */
  16
  17 #include "libbb.h"
  18 #include <sys/socket.h>
  19 #include <sys/ioctl.h>
  20
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #include <netinet/ip.h>
  25
  26 #include <net/if.h>
  27 #include <net/if_arp.h>
  28
  29 #include <asm/types.h>
  30 #ifndef __constant_htons
  31 #define __constant_htons htons
  32 #endif
  33 #include <linux/if_tunnel.h>
  34
  35 #include "rt_names.h"
  36 #include "utils.h"
  37 #include "ip_common.h"
  38
  39
  40 static int do_ioctl_get_ifindex(char *dev)
  41 {
  42         struct ifreq ifr;
  43         int fd;
  44
  45         strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name));
  46         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  47         if (ioctl(fd, SIOCGIFINDEX, &ifr)) {
  48                 bb_perror_msg("ioctl");
  49                 return 0;
  50         }
  51         close(fd);
  52         return ifr.ifr_ifindex;
  53 }
  54
  55 static int do_ioctl_get_iftype(char *dev)
  56 {
  57         struct ifreq ifr;
  58         int fd;
  59
  60         strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name));
  61         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  62         if (ioctl(fd, SIOCGIFHWADDR, &ifr)) {
  63                 bb_perror_msg("ioctl");
  64                 return -1;
  65         }
  66         close(fd);
  67         return ifr.ifr_addr.sa_family;
  68 }
  69
  70
  71 static char *do_ioctl_get_ifname(int idx)
  72 {
  73         static struct ifreq ifr;
  74         int fd;
  75
  76         ifr.ifr_ifindex = idx;
  77         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  78         if (ioctl(fd, SIOCGIFNAME, &ifr)) {
  79                 bb_perror_msg("ioctl");
  80                 return NULL;
  81         }
  82         close(fd);
  83         return ifr.ifr_name;
  84 }
  85
  86
  87
  88 static int do_get_ioctl(char *basedev, struct ip_tunnel_parm *p)
  89 {
  90         struct ifreq ifr;
  91         int fd;
  92         int err;
  93
  94         strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
  95         ifr.ifr_ifru.ifru_data = (void*)p;
  96         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  97         err = ioctl(fd, SIOCGETTUNNEL, &ifr);
  98         if (err) {
  99                 bb_perror_msg("ioctl");
 100         }
 101         close(fd);
 102         return err;
 103 }
 104
 105 static int do_add_ioctl(int cmd, char *basedev, struct ip_tunnel_parm *p)
 106 {
 107         struct ifreq ifr;
 108         int fd;
 109         int err;
 110
 111         if (cmd == SIOCCHGTUNNEL && p->name[0]) {
 112                 strncpy(ifr.ifr_name, p->name, sizeof(ifr.ifr_name));
 113         } else {
 114                 strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
 115         }
 116         ifr.ifr_ifru.ifru_data = (void*)p;
 117         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 118         err = ioctl(fd, cmd, &ifr);
 119         if (err) {
 120                 bb_perror_msg("ioctl");
 121         }
 122         close(fd);
 123         return err;
 124 }
 125
 126 static int do_del_ioctl(char *basedev, struct ip_tunnel_parm *p)
 127 {
 128         struct ifreq ifr;
 129         int fd;
 130         int err;
 131
 132         if (p->name[0]) {
 133                 strncpy(ifr.ifr_name, p->name, sizeof(ifr.ifr_name));
 134         } else {
 135                 strncpy(ifr.ifr_name, basedev, sizeof(ifr.ifr_name));
 136         }
 137         ifr.ifr_ifru.ifru_data = (void*)p;
 138         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 139         err = ioctl(fd, SIOCDELTUNNEL, &ifr);
 140         if (err) {
 141                 bb_perror_msg("ioctl");
 142         }
 143         close(fd);
 144         return err;
 145 }
 146
 147 static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
 148 {
 149         int count = 0;
 150         char medium[IFNAMSIZ];
 151         memset(p, 0, sizeof(*p));
 152         memset(&medium, 0, sizeof(medium));
 153
 154         p->iph.version = 4;
 155         p->iph.ihl = 5;
 156 #ifndef IP_DF
 157 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 158 #endif
 159         p->iph.frag_off = htons(IP_DF);
 160
 161         while (argc > 0) {
 162                 if (strcmp(*argv, "mode") == 0) {
 163                         NEXT_ARG();
 164                         if (strcmp(*argv, "ipip") == 0 ||
 165                             strcmp(*argv, "ip/ip") == 0) {
 166                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPIP) {
 167                                         bb_error_msg("you managed to ask for more than one tunnel mode");
 168                                         exit(-1);
 169                                 }
 170                                 p->iph.protocol = IPPROTO_IPIP;
 171                         } else if (strcmp(*argv, "gre") == 0 ||
 172                                    strcmp(*argv, "gre/ip") == 0) {
 173                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_GRE) {
 174                                         bb_error_msg("you managed to ask for more than one tunnel mode");
 175                                         exit(-1);
 176                                 }
 177                                 p->iph.protocol = IPPROTO_GRE;
 178                         } else if (strcmp(*argv, "sit") == 0 ||
 179                                    strcmp(*argv, "ipv6/ip") == 0) {
 180                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPV6) {
 181                                         bb_error_msg("you managed to ask for more than one tunnel mode");
 182                                         exit(-1);
 183                                 }
 184                                 p->iph.protocol = IPPROTO_IPV6;
 185                         } else {
 186                                 bb_error_msg("cannot guess tunnel mode");
 187                                 exit(-1);
 188                         }
 189                 } else if (strcmp(*argv, "key") == 0) {
 190                         unsigned uval;
 191                         NEXT_ARG();
 192                         p->i_flags |= GRE_KEY;
 193                         p->o_flags |= GRE_KEY;
 194                         if (strchr(*argv, '.'))
 195                                 p->i_key = p->o_key = get_addr32(*argv);
 196                         else {
 197                                 if (get_unsigned(&uval, *argv, 0)<0) {
 198                                         bb_error_msg("invalid value of \"key\"");
 199                                         exit(-1);
 200                                 }
 201                                 p->i_key = p->o_key = htonl(uval);
 202                         }
 203                 } else if (strcmp(*argv, "ikey") == 0) {
 204                         unsigned uval;
 205                         NEXT_ARG();
 206                         p->i_flags |= GRE_KEY;
 207                         if (strchr(*argv, '.'))
 208                                 p->o_key = get_addr32(*argv);
 209                         else {
 210                                 if (get_unsigned(&uval, *argv, 0)<0) {
 211                                         bb_error_msg("invalid value of \"ikey\"");
 212                                         exit(-1);
 213                                 }
 214                                 p->i_key = htonl(uval);
 215                         }
 216                 } else if (strcmp(*argv, "okey") == 0) {
 217                         unsigned uval;
 218                         NEXT_ARG();
 219                         p->o_flags |= GRE_KEY;
 220                         if (strchr(*argv, '.'))
 221                                 p->o_key = get_addr32(*argv);
 222                         else {
 223                                 if (get_unsigned(&uval, *argv, 0)<0) {
 224                                         bb_error_msg("invalid value of \"okey\"");
 225                                         exit(-1);
 226                                 }
 227                                 p->o_key = htonl(uval);
 228                         }
 229                 } else if (strcmp(*argv, "seq") == 0) {
 230                         p->i_flags |= GRE_SEQ;
 231                         p->o_flags |= GRE_SEQ;
 232                 } else if (strcmp(*argv, "iseq") == 0) {
 233                         p->i_flags |= GRE_SEQ;
 234                 } else if (strcmp(*argv, "oseq") == 0) {
 235                         p->o_flags |= GRE_SEQ;
 236                 } else if (strcmp(*argv, "csum") == 0) {
 237                         p->i_flags |= GRE_CSUM;
 238                         p->o_flags |= GRE_CSUM;
 239                 } else if (strcmp(*argv, "icsum") == 0) {
 240                         p->i_flags |= GRE_CSUM;
 241                 } else if (strcmp(*argv, "ocsum") == 0) {
 242                         p->o_flags |= GRE_CSUM;
 243                 } else if (strcmp(*argv, "nopmtudisc") == 0) {
 244                         p->iph.frag_off = 0;
 245                 } else if (strcmp(*argv, "pmtudisc") == 0) {
 246                         p->iph.frag_off = htons(IP_DF);
 247                 } else if (strcmp(*argv, "remote") == 0) {
 248                         NEXT_ARG();
 249                         if (strcmp(*argv, "any"))
 250                                 p->iph.daddr = get_addr32(*argv);
 251                 } else if (strcmp(*argv, "local") == 0) {
 252                         NEXT_ARG();
 253                         if (strcmp(*argv, "any"))
 254                                 p->iph.saddr = get_addr32(*argv);
 255                 } else if (strcmp(*argv, "dev") == 0) {
 256                         NEXT_ARG();
 257                         strncpy(medium, *argv, IFNAMSIZ-1);
 258                 } else if (strcmp(*argv, "ttl") == 0) {
 259                         unsigned uval;
 260                         NEXT_ARG();
 261                         if (strcmp(*argv, "inherit") != 0) {
 262                                 if (get_unsigned(&uval, *argv, 0))
 263                                         invarg(*argv, "TTL");
 264                                 if (uval > 255)
 265                                         invarg(*argv, "TTL must be <=255");
 266                                 p->iph.ttl = uval;
 267                         }
 268                 } else if (strcmp(*argv, "tos") == 0 ||
 269                            matches(*argv, "dsfield") == 0) {
 270                         uint32_t uval;
 271                         NEXT_ARG();
 272                         if (strcmp(*argv, "inherit") != 0) {
 273                                 if (rtnl_dsfield_a2n(&uval, *argv))
 274                                         invarg(*argv, "TOS");
 275                                 p->iph.tos = uval;
 276                         } else
 277                                 p->iph.tos = 1;
 278                 } else {
 279                         if (strcmp(*argv, "name") == 0) {
 280                                 NEXT_ARG();
 281                         }
 282                         if (p->name[0])
 283                                 duparg2("name", *argv);
 284                         strncpy(p->name, *argv, IFNAMSIZ);
 285                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 286                                 struct ip_tunnel_parm old_p;
 287                                 memset(&old_p, 0, sizeof(old_p));
 288                                 if (do_get_ioctl(*argv, &old_p))
 289                                         return -1;
 290                                 *p = old_p;
 291                         }
 292                 }
 293                 count++;
 294                 argc--; argv++;
 295         }
 296
 297
 298         if (p->iph.protocol == 0) {
 299                 if (memcmp(p->name, "gre", 3) == 0)
 300                         p->iph.protocol = IPPROTO_GRE;
 301                 else if (memcmp(p->name, "ipip", 4) == 0)
 302                         p->iph.protocol = IPPROTO_IPIP;
 303                 else if (memcmp(p->name, "sit", 3) == 0)
 304                         p->iph.protocol = IPPROTO_IPV6;
 305         }
 306
 307         if (p->iph.protocol == IPPROTO_IPIP || p->iph.protocol == IPPROTO_IPV6) {
 308                 if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 309                         bb_error_msg("keys are not allowed with ipip and sit");
 310                         return -1;
 311                 }
 312         }
 313
 314         if (medium[0]) {
 315                 p->link = do_ioctl_get_ifindex(medium);
 316                 if (p->link == 0)
 317                         return -1;
 318         }
 319
 320         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 321                 p->i_key = p->iph.daddr;
 322                 p->i_flags |= GRE_KEY;
 323         }
 324         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 325                 p->o_key = p->iph.daddr;
 326                 p->o_flags |= GRE_KEY;
 327         }
 328         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 329                 bb_error_msg("broadcast tunnel requires a source address");
 330                 return -1;
 331         }
 332         return 0;
 333 }
 334
 335
 336 static int do_add(int cmd, int argc, char **argv)
 337 {
 338         struct ip_tunnel_parm p;
 339
 340         if (parse_args(argc, argv, cmd, &p) < 0)
 341                 return -1;
 342
 343         if (p.iph.ttl && p.iph.frag_off == 0) {
 344                 bb_error_msg("ttl != 0 and noptmudisc are incompatible");
 345                 return -1;
 346         }
 347
 348         switch (p.iph.protocol) {
 349         case IPPROTO_IPIP:
 350                 return do_add_ioctl(cmd, "tunl0", &p);
 351         case IPPROTO_GRE:
 352                 return do_add_ioctl(cmd, "gre0", &p);
 353         case IPPROTO_IPV6:
 354                 return do_add_ioctl(cmd, "sit0", &p);
 355         default:
 356                 bb_error_msg("cannot determine tunnel mode (ipip, gre or sit)");
 357                 return -1;
 358         }
 359         return -1;
 360 }
 361
 362 static int do_del(int argc, char **argv)
 363 {
 364         struct ip_tunnel_parm p;
 365
 366         if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)
 367                 return -1;
 368
 369         switch (p.iph.protocol) {
 370         case IPPROTO_IPIP:
 371                 return do_del_ioctl("tunl0", &p);
 372         case IPPROTO_GRE:
 373                 return do_del_ioctl("gre0", &p);
 374         case IPPROTO_IPV6:
 375                 return do_del_ioctl("sit0", &p);
 376         default:
 377                 return do_del_ioctl(p.name, &p);
 378         }
 379         return -1;
 380 }
 381
 382 static void print_tunnel(struct ip_tunnel_parm *p)
 383 {
 384         char s1[256];
 385         char s2[256];
 386         char s3[64];
 387         char s4[64];
 388
 389         format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1));
 390         format_host(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2));
 391         inet_ntop(AF_INET, &p->i_key, s3, sizeof(s3));
 392         inet_ntop(AF_INET, &p->o_key, s4, sizeof(s4));
 393
 394         printf("%s: %s/ip  remote %s  local %s ",
 395                p->name,
 396                p->iph.protocol == IPPROTO_IPIP ? "ip" :
 397                (p->iph.protocol == IPPROTO_GRE ? "gre" :
 398                 (p->iph.protocol == IPPROTO_IPV6 ? "ipv6" : "unknown")),
 399                p->iph.daddr ? s1 : "any", p->iph.saddr ? s2 : "any");
 400         if (p->link) {
 401                 char *n = do_ioctl_get_ifname(p->link);
 402                 if (n)
 403                         printf(" dev %s ", n);
 404         }
 405         if (p->iph.ttl)
 406                 printf(" ttl %d ", p->iph.ttl);
 407         else
 408                 printf(" ttl inherit ");
 409         if (p->iph.tos) {
 410                 SPRINT_BUF(b1);
 411                 printf(" tos");
 412                 if (p->iph.tos & 1)
 413                         printf(" inherit");
 414                 if (p->iph.tos & ~1)
 415                         printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
 416                                rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
 417         }
 418         if (!(p->iph.frag_off & htons(IP_DF)))
 419                 printf(" nopmtudisc");
 420
 421         if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
 422                 printf(" key %s", s3);
 423         else if ((p->i_flags | p->o_flags) & GRE_KEY) {
 424                 if (p->i_flags & GRE_KEY)
 425                         printf(" ikey %s ", s3);
 426                 if (p->o_flags & GRE_KEY)
 427                         printf(" okey %s ", s4);
 428         }
 429
 430         if (p->i_flags & GRE_SEQ)
 431                 printf("%s  Drop packets out of sequence.\n", _SL_);
 432         if (p->i_flags & GRE_CSUM)
 433                 printf("%s  Checksum in received packet is required.", _SL_);
 434         if (p->o_flags & GRE_SEQ)
 435                 printf("%s  Sequence packets on output.", _SL_);
 436         if (p->o_flags & GRE_CSUM)
 437                 printf("%s  Checksum output packets.", _SL_);
 438 }
 439
 440 static int do_tunnels_list(struct ip_tunnel_parm *p)
 441 {
 442         char name[IFNAMSIZ];
 443         unsigned long rx_bytes, rx_packets, rx_errs, rx_drops,
 444                 rx_fifo, rx_frame,
 445                 tx_bytes, tx_packets, tx_errs, tx_drops,
 446                 tx_fifo, tx_colls, tx_carrier, rx_multi;
 447         int type;
 448         struct ip_tunnel_parm p1;
 449         char buf[512];
 450         FILE *fp = fopen("/proc/net/dev", "r");
 451
 452         if (fp == NULL) {
 453                 perror("fopen");
 454                 return -1;
 455         }
 456
 457         fgets(buf, sizeof(buf), fp);
 458         fgets(buf, sizeof(buf), fp);
 459
 460         while (fgets(buf, sizeof(buf), fp) != NULL) {
 461                 char *ptr;
 462
 463                 /*buf[sizeof(buf) - 1] = 0; - fgets is safe anyway */
 464                 ptr = strchr(buf, ':');
 465                 if (ptr == NULL ||
 466                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 467                         bb_error_msg("wrong format of /proc/net/dev. Sorry");
 468                         return -1;
 469                 }
 470                 if (sscanf(ptr, "%lu%lu%lu%lu%lu%lu%lu%*d%lu%lu%lu%lu%lu%lu%lu",
 471                            &rx_bytes, &rx_packets, &rx_errs, &rx_drops,
 472                            &rx_fifo, &rx_frame, &rx_multi,
 473                            &tx_bytes, &tx_packets, &tx_errs, &tx_drops,
 474                            &tx_fifo, &tx_colls, &tx_carrier) != 14)
 475                         continue;
 476                 if (p->name[0] && strcmp(p->name, name))
 477                         continue;
 478                 type = do_ioctl_get_iftype(name);
 479                 if (type == -1) {
 480                         bb_error_msg("failed to get type of [%s]", name);
 481                         continue;
 482                 }
 483                 if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
 484                         continue;
 485                 memset(&p1, 0, sizeof(p1));
 486                 if (do_get_ioctl(name, &p1))
 487                         continue;
 488                 if ((p->link && p1.link != p->link) ||
 489                     (p->name[0] && strcmp(p1.name, p->name)) ||
 490                     (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
 491                     (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
 492                     (p->i_key && p1.i_key != p->i_key))
 493                         continue;
 494                 print_tunnel(&p1);
 495                 puts("");
 496         }
 497         return 0;
 498 }
 499
 500 static int do_show(int argc, char **argv)
 501 {
 502         int err;
 503         struct ip_tunnel_parm p;
 504
 505         if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)
 506                 return -1;
 507
 508         switch (p.iph.protocol) {
 509         case IPPROTO_IPIP:
 510                 err = do_get_ioctl(p.name[0] ? p.name : "tunl0", &p);
 511                 break;
 512         case IPPROTO_GRE:
 513                 err = do_get_ioctl(p.name[0] ? p.name : "gre0", &p);
 514                 break;
 515         case IPPROTO_IPV6:
 516                 err = do_get_ioctl(p.name[0] ? p.name : "sit0", &p);
 517                 break;
 518         default:
 519                 do_tunnels_list(&p);
 520                 return 0;
 521         }
 522         if (err)
 523                 return -1;
 524
 525         print_tunnel(&p);
 526         puts("");
 527         return 0;
 528 }
 529
 530 int do_iptunnel(int argc, char **argv)
 531 {
 532         if (argc > 0) {
 533                 if (matches(*argv, "add") == 0)
 534                         return do_add(SIOCADDTUNNEL, argc-1, argv+1);
 535                 if (matches(*argv, "change") == 0)
 536                         return do_add(SIOCCHGTUNNEL, argc-1, argv+1);
 537                 if (matches(*argv, "del") == 0)
 538                         return do_del(argc-1, argv+1);
 539                 if (matches(*argv, "show") == 0 ||
 540                     matches(*argv, "lst") == 0 ||
 541                     matches(*argv, "list") == 0)
 542                         return do_show(argc-1, argv+1);
 543         } else
 544                 return do_show(0, NULL);
 545
 546         bb_error_msg_and_die("command \"%s\" is unknown", *argv);
 547 }