networking/libiproute/iptunnel.c

   1 /*
   2  * iptunnel.c          "ip tunnel"
   3  *
   4  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   5  *
   6  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   7  *
   8  *
   9  * Changes:
  10  *
  11  * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
  12  * Rani Assaf <rani@magic.metawire.com> 980930: do not allow key for ipip/sit
  13  * Phil Karn <karn@ka9q.ampr.org>       990408: "pmtudisc" flag
  14  */
  15
  16 #include "libbb.h"
  17 #include <sys/socket.h>
  18 #include <sys/ioctl.h>
  19
  20 #include <string.h>
  21 #include <unistd.h>
  22
  23 #include <netinet/ip.h>
  24
  25 #include <net/if.h>
  26 #include <net/if_arp.h>
  27
  28 #include <asm/types.h>
  29 #ifndef __constant_htons
  30 #define __constant_htons htons
  31 #endif
  32 #include <linux/if_tunnel.h>
  33
  34 #include "rt_names.h"
  35 #include "utils.h"
  36 #include "ip_common.h"
  37
  38
  39 static int do_ioctl_get_ifindex(char *dev)
  40 {
  41         struct ifreq ifr;
  42         int fd;
  43
  44         strcpy(ifr.ifr_name, dev);
  45         fd = socket(AF_INET, SOCK_DGRAM, 0);
  46         if (ioctl(fd, SIOCGIFINDEX, &ifr)) {
  47                 bb_perror_msg("ioctl");
  48                 return 0;
  49         }
  50         close(fd);
  51         return ifr.ifr_ifindex;
  52 }
  53
  54 static int do_ioctl_get_iftype(char *dev)
  55 {
  56         struct ifreq ifr;
  57         int fd;
  58
  59         strcpy(ifr.ifr_name, dev);
  60         fd = socket(AF_INET, SOCK_DGRAM, 0);
  61         if (ioctl(fd, SIOCGIFHWADDR, &ifr)) {
  62                 bb_perror_msg("ioctl");
  63                 return -1;
  64         }
  65         close(fd);
  66         return ifr.ifr_addr.sa_family;
  67 }
  68
  69
  70 static char *do_ioctl_get_ifname(int idx)
  71 {
  72         static struct ifreq ifr;
  73         int fd;
  74
  75         ifr.ifr_ifindex = idx;
  76         fd = socket(AF_INET, SOCK_DGRAM, 0);
  77         if (ioctl(fd, SIOCGIFNAME, &ifr)) {
  78                 bb_perror_msg("ioctl");
  79                 return NULL;
  80         }
  81         close(fd);
  82         return ifr.ifr_name;
  83 }
  84
  85
  86
  87 static int do_get_ioctl(char *basedev, struct ip_tunnel_parm *p)
  88 {
  89         struct ifreq ifr;
  90         int fd;
  91         int err;
  92
  93         strcpy(ifr.ifr_name, basedev);
  94         ifr.ifr_ifru.ifru_data = (void*)p;
  95         fd = socket(AF_INET, SOCK_DGRAM, 0);
  96         err = ioctl(fd, SIOCGETTUNNEL, &ifr);
  97         if (err) {
  98                 bb_perror_msg("ioctl");
  99         }
 100         close(fd);
 101         return err;
 102 }
 103
 104 static int do_add_ioctl(int cmd, char *basedev, struct ip_tunnel_parm *p)
 105 {
 106         struct ifreq ifr;
 107         int fd;
 108         int err;
 109
 110         if (cmd == SIOCCHGTUNNEL && p->name[0]) {
 111                 strcpy(ifr.ifr_name, p->name);
 112         } else {
 113                 strcpy(ifr.ifr_name, basedev);
 114         }
 115         ifr.ifr_ifru.ifru_data = (void*)p;
 116         fd = socket(AF_INET, SOCK_DGRAM, 0);
 117         err = ioctl(fd, cmd, &ifr);
 118         if (err) {
 119                 bb_perror_msg("ioctl");
 120         }
 121         close(fd);
 122         return err;
 123 }
 124
 125 static int do_del_ioctl(char *basedev, struct ip_tunnel_parm *p)
 126 {
 127         struct ifreq ifr;
 128         int fd;
 129         int err;
 130
 131         if (p->name[0]) {
 132                 strcpy(ifr.ifr_name, p->name);
 133         } else {
 134                 strcpy(ifr.ifr_name, basedev);
 135         }
 136         ifr.ifr_ifru.ifru_data = (void*)p;
 137         fd = socket(AF_INET, SOCK_DGRAM, 0);
 138         err = ioctl(fd, SIOCDELTUNNEL, &ifr);
 139         if (err) {
 140                 bb_perror_msg("ioctl");
 141         }
 142         close(fd);
 143         return err;
 144 }
 145
 146 static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
 147 {
 148         int count = 0;
 149         char medium[IFNAMSIZ];
 150         memset(p, 0, sizeof(*p));
 151         memset(&medium, 0, sizeof(medium));
 152
 153         p->iph.version = 4;
 154         p->iph.ihl = 5;
 155 #ifndef IP_DF
 156 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 157 #endif
 158         p->iph.frag_off = htons(IP_DF);
 159
 160         while (argc > 0) {
 161                 if (strcmp(*argv, "mode") == 0) {
 162                         NEXT_ARG();
 163                         if (strcmp(*argv, "ipip") == 0 ||
 164                             strcmp(*argv, "ip/ip") == 0) {
 165                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPIP) {
 166                                         bb_error_msg("You managed to ask for more than one tunnel mode.");
 167                                         exit(-1);
 168                                 }
 169                                 p->iph.protocol = IPPROTO_IPIP;
 170                         } else if (strcmp(*argv, "gre") == 0 ||
 171                                    strcmp(*argv, "gre/ip") == 0) {
 172                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_GRE) {
 173                                         bb_error_msg("You managed to ask for more than one tunnel mode.");
 174                                         exit(-1);
 175                                 }
 176                                 p->iph.protocol = IPPROTO_GRE;
 177                         } else if (strcmp(*argv, "sit") == 0 ||
 178                                    strcmp(*argv, "ipv6/ip") == 0) {
 179                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPV6) {
 180                                         bb_error_msg("You managed to ask for more than one tunnel mode.");
 181                                         exit(-1);
 182                                 }
 183                                 p->iph.protocol = IPPROTO_IPV6;
 184                         } else {
 185                                 bb_error_msg("Cannot guess tunnel mode.");
 186                                 exit(-1);
 187                         }
 188                 } else if (strcmp(*argv, "key") == 0) {
 189                         unsigned uval;
 190                         NEXT_ARG();
 191                         p->i_flags |= GRE_KEY;
 192                         p->o_flags |= GRE_KEY;
 193                         if (strchr(*argv, '.'))
 194                                 p->i_key = p->o_key = get_addr32(*argv);
 195                         else {
 196                                 if (get_unsigned(&uval, *argv, 0)<0) {
 197                                         bb_error_msg("invalid value of \"key\"");
 198                                         exit(-1);
 199                                 }
 200                                 p->i_key = p->o_key = htonl(uval);
 201                         }
 202                 } else if (strcmp(*argv, "ikey") == 0) {
 203                         unsigned uval;
 204                         NEXT_ARG();
 205                         p->i_flags |= GRE_KEY;
 206                         if (strchr(*argv, '.'))
 207                                 p->o_key = get_addr32(*argv);
 208                         else {
 209                                 if (get_unsigned(&uval, *argv, 0)<0) {
 210                                         bb_error_msg("invalid value of \"ikey\"");
 211                                         exit(-1);
 212                                 }
 213                                 p->i_key = htonl(uval);
 214                         }
 215                 } else if (strcmp(*argv, "okey") == 0) {
 216                         unsigned uval;
 217                         NEXT_ARG();
 218                         p->o_flags |= GRE_KEY;
 219                         if (strchr(*argv, '.'))
 220                                 p->o_key = get_addr32(*argv);
 221                         else {
 222                                 if (get_unsigned(&uval, *argv, 0)<0) {
 223                                         bb_error_msg("invalid value of \"okey\"");
 224                                         exit(-1);
 225                                 }
 226                                 p->o_key = htonl(uval);
 227                         }
 228                 } else if (strcmp(*argv, "seq") == 0) {
 229                         p->i_flags |= GRE_SEQ;
 230                         p->o_flags |= GRE_SEQ;
 231                 } else if (strcmp(*argv, "iseq") == 0) {
 232                         p->i_flags |= GRE_SEQ;
 233                 } else if (strcmp(*argv, "oseq") == 0) {
 234                         p->o_flags |= GRE_SEQ;
 235                 } else if (strcmp(*argv, "csum") == 0) {
 236                         p->i_flags |= GRE_CSUM;
 237                         p->o_flags |= GRE_CSUM;
 238                 } else if (strcmp(*argv, "icsum") == 0) {
 239                         p->i_flags |= GRE_CSUM;
 240                 } else if (strcmp(*argv, "ocsum") == 0) {
 241                         p->o_flags |= GRE_CSUM;
 242                 } else if (strcmp(*argv, "nopmtudisc") == 0) {
 243                         p->iph.frag_off = 0;
 244                 } else if (strcmp(*argv, "pmtudisc") == 0) {
 245                         p->iph.frag_off = htons(IP_DF);
 246                 } else if (strcmp(*argv, "remote") == 0) {
 247                         NEXT_ARG();
 248                         if (strcmp(*argv, "any"))
 249                                 p->iph.daddr = get_addr32(*argv);
 250                 } else if (strcmp(*argv, "local") == 0) {
 251                         NEXT_ARG();
 252                         if (strcmp(*argv, "any"))
 253                                 p->iph.saddr = get_addr32(*argv);
 254                 } else if (strcmp(*argv, "dev") == 0) {
 255                         NEXT_ARG();
 256                         strncpy(medium, *argv, IFNAMSIZ-1);
 257                 } else if (strcmp(*argv, "ttl") == 0) {
 258                         unsigned uval;
 259                         NEXT_ARG();
 260                         if (strcmp(*argv, "inherit") != 0) {
 261                                 if (get_unsigned(&uval, *argv, 0))
 262                                         invarg(*argv, "TTL");
 263                                 if (uval > 255)
 264                                         invarg(*argv, "TTL must be <=255");
 265                                 p->iph.ttl = uval;
 266                         }
 267                 } else if (strcmp(*argv, "tos") == 0 ||
 268                            matches(*argv, "dsfield") == 0) {
 269                         __u32 uval;
 270                         NEXT_ARG();
 271                         if (strcmp(*argv, "inherit") != 0) {
 272                                 if (rtnl_dsfield_a2n(&uval, *argv))
 273                                         invarg(*argv, "TOS");
 274                                 p->iph.tos = uval;
 275                         } else
 276                                 p->iph.tos = 1;
 277                 } else {
 278                         if (strcmp(*argv, "name") == 0) {
 279                                 NEXT_ARG();
 280                         }
 281                         if (p->name[0])
 282                                 duparg2("name", *argv);
 283                         strncpy(p->name, *argv, IFNAMSIZ);
 284                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 285                                 struct ip_tunnel_parm old_p;
 286                                 memset(&old_p, 0, sizeof(old_p));
 287                                 if (do_get_ioctl(*argv, &old_p))
 288                                         return -1;
 289                                 *p = old_p;
 290                         }
 291                 }
 292                 count++;
 293                 argc--; argv++;
 294         }
 295
 296
 297         if (p->iph.protocol == 0) {
 298                 if (memcmp(p->name, "gre", 3) == 0)
 299                         p->iph.protocol = IPPROTO_GRE;
 300                 else if (memcmp(p->name, "ipip", 4) == 0)
 301                         p->iph.protocol = IPPROTO_IPIP;
 302                 else if (memcmp(p->name, "sit", 3) == 0)
 303                         p->iph.protocol = IPPROTO_IPV6;
 304         }
 305
 306         if (p->iph.protocol == IPPROTO_IPIP || p->iph.protocol == IPPROTO_IPV6) {
 307                 if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 308                         bb_error_msg("Keys are not allowed with ipip and sit.");
 309                         return -1;
 310                 }
 311         }
 312
 313         if (medium[0]) {
 314                 p->link = do_ioctl_get_ifindex(medium);
 315                 if (p->link == 0)
 316                         return -1;
 317         }
 318
 319         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 320                 p->i_key = p->iph.daddr;
 321                 p->i_flags |= GRE_KEY;
 322         }
 323         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 324                 p->o_key = p->iph.daddr;
 325                 p->o_flags |= GRE_KEY;
 326         }
 327         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 328                 bb_error_msg("Broadcast tunnel requires a source address.");
 329                 return -1;
 330         }
 331         return 0;
 332 }
 333
 334
 335 static int do_add(int cmd, int argc, char **argv)
 336 {
 337         struct ip_tunnel_parm p;
 338
 339         if (parse_args(argc, argv, cmd, &p) < 0)
 340                 return -1;
 341
 342         if (p.iph.ttl && p.iph.frag_off == 0) {
 343                 bb_error_msg("ttl != 0 and noptmudisc are incompatible");
 344                 return -1;
 345         }
 346
 347         switch (p.iph.protocol) {
 348         case IPPROTO_IPIP:
 349                 return do_add_ioctl(cmd, "tunl0", &p);
 350         case IPPROTO_GRE:
 351                 return do_add_ioctl(cmd, "gre0", &p);
 352         case IPPROTO_IPV6:
 353                 return do_add_ioctl(cmd, "sit0", &p);
 354         default:
 355                 bb_error_msg("cannot determine tunnel mode (ipip, gre or sit)");
 356                 return -1;
 357         }
 358         return -1;
 359 }
 360
 361 static int do_del(int argc, char **argv)
 362 {
 363         struct ip_tunnel_parm p;
 364
 365         if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)
 366                 return -1;
 367
 368         switch (p.iph.protocol) {
 369         case IPPROTO_IPIP:
 370                 return do_del_ioctl("tunl0", &p);
 371         case IPPROTO_GRE:
 372                 return do_del_ioctl("gre0", &p);
 373         case IPPROTO_IPV6:
 374                 return do_del_ioctl("sit0", &p);
 375         default:
 376                 return do_del_ioctl(p.name, &p);
 377         }
 378         return -1;
 379 }
 380
 381 static void print_tunnel(struct ip_tunnel_parm *p)
 382 {
 383         char s1[256];
 384         char s2[256];
 385         char s3[64];
 386         char s4[64];
 387
 388         format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1));
 389         format_host(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2));
 390         inet_ntop(AF_INET, &p->i_key, s3, sizeof(s3));
 391         inet_ntop(AF_INET, &p->o_key, s4, sizeof(s4));
 392
 393         printf("%s: %s/ip  remote %s  local %s ",
 394                p->name,
 395                p->iph.protocol == IPPROTO_IPIP ? "ip" :
 396                (p->iph.protocol == IPPROTO_GRE ? "gre" :
 397                 (p->iph.protocol == IPPROTO_IPV6 ? "ipv6" : "unknown")),
 398                p->iph.daddr ? s1 : "any", p->iph.saddr ? s2 : "any");
 399         if (p->link) {
 400                 char *n = do_ioctl_get_ifname(p->link);
 401                 if (n)
 402                         printf(" dev %s ", n);
 403         }
 404         if (p->iph.ttl)
 405                 printf(" ttl %d ", p->iph.ttl);
 406         else
 407                 printf(" ttl inherit ");
 408         if (p->iph.tos) {
 409                 SPRINT_BUF(b1);
 410                 printf(" tos");
 411                 if (p->iph.tos&1)
 412                         printf(" inherit");
 413                 if (p->iph.tos&~1)
 414                         printf("%c%s ", p->iph.tos&1 ? '/' : ' ',
 415                                rtnl_dsfield_n2a(p->iph.tos&~1, b1, sizeof(b1)));
 416         }
 417         if (!(p->iph.frag_off&htons(IP_DF)))
 418                 printf(" nopmtudisc");
 419
 420         if ((p->i_flags&GRE_KEY) && (p->o_flags&GRE_KEY) && p->o_key == p->i_key)
 421                 printf(" key %s", s3);
 422         else if ((p->i_flags|p->o_flags)&GRE_KEY) {
 423                 if (p->i_flags&GRE_KEY)
 424                         printf(" ikey %s ", s3);
 425                 if (p->o_flags&GRE_KEY)
 426                         printf(" okey %s ", s4);
 427         }
 428
 429         if (p->i_flags&GRE_SEQ)
 430                 printf("%s  Drop packets out of sequence.\n", _SL_);
 431         if (p->i_flags&GRE_CSUM)
 432                 printf("%s  Checksum in received packet is required.", _SL_);
 433         if (p->o_flags&GRE_SEQ)
 434                 printf("%s  Sequence packets on output.", _SL_);
 435         if (p->o_flags&GRE_CSUM)
 436                 printf("%s  Checksum output packets.", _SL_);
 437 }
 438
 439 static int do_tunnels_list(struct ip_tunnel_parm *p)
 440 {
 441         char name[IFNAMSIZ];
 442         unsigned long  rx_bytes, rx_packets, rx_errs, rx_drops,
 443         rx_fifo, rx_frame,
 444         tx_bytes, tx_packets, tx_errs, tx_drops,
 445         tx_fifo, tx_colls, tx_carrier, rx_multi;
 446         int type;
 447         struct ip_tunnel_parm p1;
 448
 449         char buf[512];
 450         FILE *fp = fopen("/proc/net/dev", "r");
 451         if (fp == NULL) {
 452                 perror("fopen");
 453                 return -1;
 454         }
 455
 456         fgets(buf, sizeof(buf), fp);
 457         fgets(buf, sizeof(buf), fp);
 458
 459         while (fgets(buf, sizeof(buf), fp) != NULL) {
 460                 char *ptr;
 461                 buf[sizeof(buf) - 1] = 0;
 462                 if ((ptr = strchr(buf, ':')) == NULL ||
 463                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 464                         bb_error_msg("Wrong format of /proc/net/dev. Sorry.");
 465                         return -1;
 466                 }
 467                 if (sscanf(ptr, "%lu%lu%lu%lu%lu%lu%lu%*d%lu%lu%lu%lu%lu%lu%lu",
 468                            &rx_bytes, &rx_packets, &rx_errs, &rx_drops,
 469                            &rx_fifo, &rx_frame, &rx_multi,
 470                            &tx_bytes, &tx_packets, &tx_errs, &tx_drops,
 471                            &tx_fifo, &tx_colls, &tx_carrier) != 14)
 472                         continue;
 473                 if (p->name[0] && strcmp(p->name, name))
 474                         continue;
 475                 type = do_ioctl_get_iftype(name);
 476                 if (type == -1) {
 477                         bb_error_msg("Failed to get type of [%s]", name);
 478                         continue;
 479                 }
 480                 if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
 481                         continue;
 482                 memset(&p1, 0, sizeof(p1));
 483                 if (do_get_ioctl(name, &p1))
 484                         continue;
 485                 if ((p->link && p1.link != p->link) ||
 486                     (p->name[0] && strcmp(p1.name, p->name)) ||
 487                     (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
 488                     (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
 489                     (p->i_key && p1.i_key != p->i_key))
 490                         continue;
 491                 print_tunnel(&p1);
 492                 printf("\n");
 493         }
 494         return 0;
 495 }
 496
 497 static int do_show(int argc, char **argv)
 498 {
 499         int err;
 500         struct ip_tunnel_parm p;
 501
 502         if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)
 503                 return -1;
 504
 505         switch (p.iph.protocol) {
 506         case IPPROTO_IPIP:
 507                 err = do_get_ioctl(p.name[0] ? p.name : "tunl0", &p);
 508                 break;
 509         case IPPROTO_GRE:
 510                 err = do_get_ioctl(p.name[0] ? p.name : "gre0", &p);
 511                 break;
 512         case IPPROTO_IPV6:
 513                 err = do_get_ioctl(p.name[0] ? p.name : "sit0", &p);
 514                 break;
 515         default:
 516                 do_tunnels_list(&p);
 517                 return 0;
 518         }
 519         if (err)
 520                 return -1;
 521
 522         print_tunnel(&p);
 523         printf("\n");
 524         return 0;
 525 }
 526
 527 int do_iptunnel(int argc, char **argv)
 528 {
 529         if (argc > 0) {
 530                 if (matches(*argv, "add") == 0)
 531                         return do_add(SIOCADDTUNNEL, argc-1, argv+1);
 532                 if (matches(*argv, "change") == 0)
 533                         return do_add(SIOCCHGTUNNEL, argc-1, argv+1);
 534                 if (matches(*argv, "del") == 0)
 535                         return do_del(argc-1, argv+1);
 536                 if (matches(*argv, "show") == 0 ||
 537                     matches(*argv, "lst") == 0 ||
 538                     matches(*argv, "list") == 0)
 539                         return do_show(argc-1, argv+1);
 540         } else
 541                 return do_show(0, NULL);
 542
 543         bb_error_msg("Command \"%s\" is unknown.", *argv);
 544         exit(-1);
 545 }