release/src/router/busybox/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  * 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 <netinet/ip.h>
  17 #include <net/if.h>
  18 #include <net/if_arp.h>
  19 #include <asm/types.h>
  20
  21 #ifndef __constant_htons
  22 #define __constant_htons htons
  23 #endif
  24
  25 // FYI: #define SIOCDEVPRIVATE 0x89F0
  26
  27 /* From linux/if_tunnel.h. #including it proved troublesome
  28  * (redefiniton errors due to name collisions in linux/ and net[inet]/) */
  29 #define SIOCGETTUNNEL   (SIOCDEVPRIVATE + 0)
  30 #define SIOCADDTUNNEL   (SIOCDEVPRIVATE + 1)
  31 #define SIOCDELTUNNEL   (SIOCDEVPRIVATE + 2)
  32 #define SIOCCHGTUNNEL   (SIOCDEVPRIVATE + 3)
  33 //#define SIOCGETPRL      (SIOCDEVPRIVATE + 4)
  34 //#define SIOCADDPRL      (SIOCDEVPRIVATE + 5)
  35 //#define SIOCDELPRL      (SIOCDEVPRIVATE + 6)
  36 //#define SIOCCHGPRL      (SIOCDEVPRIVATE + 7)
  37 #define GRE_CSUM        __constant_htons(0x8000)
  38 //#define GRE_ROUTING     __constant_htons(0x4000)
  39 #define GRE_KEY         __constant_htons(0x2000)
  40 #define GRE_SEQ         __constant_htons(0x1000)
  41 //#define GRE_STRICT      __constant_htons(0x0800)
  42 //#define GRE_REC         __constant_htons(0x0700)
  43 //#define GRE_FLAGS       __constant_htons(0x00F8)
  44 //#define GRE_VERSION     __constant_htons(0x0007)
  45 struct ip_tunnel_parm {
  46         char            name[IFNAMSIZ];
  47         int             link;
  48         uint16_t        i_flags;
  49         uint16_t        o_flags;
  50         uint32_t        i_key;
  51         uint32_t        o_key;
  52         struct iphdr    iph;
  53 };
  54 /* SIT-mode i_flags */
  55 //#define SIT_ISATAP 0x0001
  56 //struct ip_tunnel_prl {
  57 //      uint32_t          addr;
  58 //      uint16_t          flags;
  59 //      uint16_t          __reserved;
  60 //      uint32_t          datalen;
  61 //      uint32_t          __reserved2;
  62 //      /* data follows */
  63 //};
  64 ///* PRL flags */
  65 //#define PRL_DEFAULT 0x0001
  66
  67 #include "ip_common.h"  /* #include "libbb.h" is inside */
  68 #include "rt_names.h"
  69 #include "utils.h"
  70
  71
  72 /* Dies on error */
  73 static int do_ioctl_get_ifindex(char *dev)
  74 {
  75         struct ifreq ifr;
  76         int fd;
  77
  78         strncpy_IFNAMSIZ(ifr.ifr_name, dev);
  79         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  80         xioctl(fd, SIOCGIFINDEX, &ifr);
  81         close(fd);
  82         return ifr.ifr_ifindex;
  83 }
  84
  85 static int do_ioctl_get_iftype(char *dev)
  86 {
  87         struct ifreq ifr;
  88         int fd;
  89         int err;
  90
  91         strncpy_IFNAMSIZ(ifr.ifr_name, dev);
  92         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
  93         err = ioctl_or_warn(fd, SIOCGIFHWADDR, &ifr);
  94         close(fd);
  95         return err ? -1 : ifr.ifr_addr.sa_family;
  96 }
  97
  98 static char *do_ioctl_get_ifname(int idx)
  99 {
 100         struct ifreq ifr;
 101         int fd;
 102         int err;
 103
 104         ifr.ifr_ifindex = idx;
 105         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 106         err = ioctl_or_warn(fd, SIOCGIFNAME, &ifr);
 107         close(fd);
 108         return err ? NULL : xstrndup(ifr.ifr_name, sizeof(ifr.ifr_name));
 109 }
 110
 111 static int do_get_ioctl(const char *basedev, struct ip_tunnel_parm *p)
 112 {
 113         struct ifreq ifr;
 114         int fd;
 115         int err;
 116
 117         strncpy_IFNAMSIZ(ifr.ifr_name, basedev);
 118         ifr.ifr_ifru.ifru_data = (void*)p;
 119         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 120         err = ioctl_or_warn(fd, SIOCGETTUNNEL, &ifr);
 121         close(fd);
 122         return err;
 123 }
 124
 125 /* Dies on error, otherwise returns 0 */
 126 static int do_add_ioctl(int cmd, const char *basedev, struct ip_tunnel_parm *p)
 127 {
 128         struct ifreq ifr;
 129         int fd;
 130
 131         if (cmd == SIOCCHGTUNNEL && p->name[0]) {
 132                 strncpy_IFNAMSIZ(ifr.ifr_name, p->name);
 133         } else {
 134                 strncpy_IFNAMSIZ(ifr.ifr_name, basedev);
 135         }
 136         ifr.ifr_ifru.ifru_data = (void*)p;
 137         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 138 #if ENABLE_IOCTL_HEX2STR_ERROR
 139         /* #define magic will turn ioctl# into string */
 140         if (cmd == SIOCCHGTUNNEL)
 141                 xioctl(fd, SIOCCHGTUNNEL, &ifr);
 142         else
 143                 xioctl(fd, SIOCADDTUNNEL, &ifr);
 144 #else
 145         xioctl(fd, cmd, &ifr);
 146 #endif
 147         close(fd);
 148         return 0;
 149 }
 150
 151 /* Dies on error, otherwise returns 0 */
 152 static int do_del_ioctl(const char *basedev, struct ip_tunnel_parm *p)
 153 {
 154         struct ifreq ifr;
 155         int fd;
 156
 157         if (p->name[0]) {
 158                 strncpy_IFNAMSIZ(ifr.ifr_name, p->name);
 159         } else {
 160                 strncpy_IFNAMSIZ(ifr.ifr_name, basedev);
 161         }
 162         ifr.ifr_ifru.ifru_data = (void*)p;
 163         fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 164         xioctl(fd, SIOCDELTUNNEL, &ifr);
 165         close(fd);
 166         return 0;
 167 }
 168
 169 /* Dies on error */
 170 static void parse_args(char **argv, int cmd, struct ip_tunnel_parm *p)
 171 {
 172         static const char keywords[] ALIGN1 =
 173                 "mode\0""ipip\0""ip/ip\0""gre\0""gre/ip\0""sit\0""ipv6/ip\0"
 174                 "key\0""ikey\0""okey\0""seq\0""iseq\0""oseq\0"
 175                 "csum\0""icsum\0""ocsum\0""nopmtudisc\0""pmtudisc\0"
 176                 "remote\0""any\0""local\0""dev\0"
 177                 "ttl\0""inherit\0""tos\0""dsfield\0"
 178                 "name\0";
 179         enum {
 180                 ARG_mode, ARG_ipip, ARG_ip_ip, ARG_gre, ARG_gre_ip, ARG_sit, ARG_ip6_ip,
 181                 ARG_key, ARG_ikey, ARG_okey, ARG_seq, ARG_iseq, ARG_oseq,
 182                 ARG_csum, ARG_icsum, ARG_ocsum, ARG_nopmtudisc, ARG_pmtudisc,
 183                 ARG_remote, ARG_any, ARG_local, ARG_dev,
 184                 ARG_ttl, ARG_inherit, ARG_tos, ARG_dsfield,
 185                 ARG_name
 186         };
 187         int count = 0;
 188         char medium[IFNAMSIZ];
 189         int key;
 190
 191         memset(p, 0, sizeof(*p));
 192         medium[0] = '\0';
 193
 194         p->iph.version = 4;
 195         p->iph.ihl = 5;
 196 #ifndef IP_DF
 197 #define IP_DF 0x4000  /* Flag: "Don't Fragment" */
 198 #endif
 199         p->iph.frag_off = htons(IP_DF);
 200
 201         while (*argv) {
 202                 key = index_in_strings(keywords, *argv);
 203                 if (key == ARG_mode) {
 204                         NEXT_ARG();
 205                         key = index_in_strings(keywords, *argv);
 206                         if (key == ARG_ipip ||
 207                             key == ARG_ip_ip) {
 208                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPIP) {
 209                                         bb_error_msg_and_die("%s tunnel mode", "you managed to ask for more than one");
 210                                 }
 211                                 p->iph.protocol = IPPROTO_IPIP;
 212                         } else if (key == ARG_gre ||
 213                                    key == ARG_gre_ip) {
 214                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_GRE) {
 215                                         bb_error_msg_and_die("%s tunnel mode", "you managed to ask for more than one");
 216                                 }
 217                                 p->iph.protocol = IPPROTO_GRE;
 218                         } else if (key == ARG_sit ||
 219                                    key == ARG_ip6_ip) {
 220                                 if (p->iph.protocol && p->iph.protocol != IPPROTO_IPV6) {
 221                                         bb_error_msg_and_die("%s tunnel mode", "you managed to ask for more than one");
 222                                 }
 223                                 p->iph.protocol = IPPROTO_IPV6;
 224                         } else {
 225                                 bb_error_msg_and_die("%s tunnel mode", "cannot guess");
 226                         }
 227                 } else if (key == ARG_key) {
 228                         unsigned uval;
 229                         NEXT_ARG();
 230                         p->i_flags |= GRE_KEY;
 231                         p->o_flags |= GRE_KEY;
 232                         if (strchr(*argv, '.'))
 233                                 p->i_key = p->o_key = get_addr32(*argv);
 234                         else {
 235                                 uval = get_unsigned(*argv, "key");
 236                                 p->i_key = p->o_key = htonl(uval);
 237                         }
 238                 } else if (key == ARG_ikey) {
 239                         unsigned uval;
 240                         NEXT_ARG();
 241                         p->i_flags |= GRE_KEY;
 242                         if (strchr(*argv, '.'))
 243                                 p->o_key = get_addr32(*argv);
 244                         else {
 245                                 uval = get_unsigned(*argv, "ikey");
 246                                 p->i_key = htonl(uval);
 247                         }
 248                 } else if (key == ARG_okey) {
 249                         unsigned uval;
 250                         NEXT_ARG();
 251                         p->o_flags |= GRE_KEY;
 252                         if (strchr(*argv, '.'))
 253                                 p->o_key = get_addr32(*argv);
 254                         else {
 255                                 uval = get_unsigned(*argv, "okey");
 256                                 p->o_key = htonl(uval);
 257                         }
 258                 } else if (key == ARG_seq) {
 259                         p->i_flags |= GRE_SEQ;
 260                         p->o_flags |= GRE_SEQ;
 261                 } else if (key == ARG_iseq) {
 262                         p->i_flags |= GRE_SEQ;
 263                 } else if (key == ARG_oseq) {
 264                         p->o_flags |= GRE_SEQ;
 265                 } else if (key == ARG_csum) {
 266                         p->i_flags |= GRE_CSUM;
 267                         p->o_flags |= GRE_CSUM;
 268                 } else if (key == ARG_icsum) {
 269                         p->i_flags |= GRE_CSUM;
 270                 } else if (key == ARG_ocsum) {
 271                         p->o_flags |= GRE_CSUM;
 272                 } else if (key == ARG_nopmtudisc) {
 273                         p->iph.frag_off = 0;
 274                 } else if (key == ARG_pmtudisc) {
 275                         p->iph.frag_off = htons(IP_DF);
 276                 } else if (key == ARG_remote) {
 277                         NEXT_ARG();
 278                         key = index_in_strings(keywords, *argv);
 279                         if (key != ARG_any)
 280                                 p->iph.daddr = get_addr32(*argv);
 281                 } else if (key == ARG_local) {
 282                         NEXT_ARG();
 283                         key = index_in_strings(keywords, *argv);
 284                         if (key != ARG_any)
 285                                 p->iph.saddr = get_addr32(*argv);
 286                 } else if (key == ARG_dev) {
 287                         NEXT_ARG();
 288                         strncpy_IFNAMSIZ(medium, *argv);
 289                 } else if (key == ARG_ttl) {
 290                         unsigned uval;
 291                         NEXT_ARG();
 292                         key = index_in_strings(keywords, *argv);
 293                         if (key != ARG_inherit) {
 294                                 uval = get_unsigned(*argv, "TTL");
 295                                 if (uval > 255)
 296                                         invarg(*argv, "TTL must be <=255");
 297                                 p->iph.ttl = uval;
 298                         }
 299                 } else if (key == ARG_tos ||
 300                            key == ARG_dsfield) {
 301                         uint32_t uval;
 302                         NEXT_ARG();
 303                         key = index_in_strings(keywords, *argv);
 304                         if (key != ARG_inherit) {
 305                                 if (rtnl_dsfield_a2n(&uval, *argv))
 306                                         invarg(*argv, "TOS");
 307                                 p->iph.tos = uval;
 308                         } else
 309                                 p->iph.tos = 1;
 310                 } else {
 311                         if (key == ARG_name) {
 312                                 NEXT_ARG();
 313                         }
 314                         if (p->name[0])
 315                                 duparg2("name", *argv);
 316                         strncpy_IFNAMSIZ(p->name, *argv);
 317                         if (cmd == SIOCCHGTUNNEL && count == 0) {
 318                                 struct ip_tunnel_parm old_p;
 319                                 memset(&old_p, 0, sizeof(old_p));
 320                                 if (do_get_ioctl(*argv, &old_p))
 321                                         exit(EXIT_FAILURE);
 322                                 *p = old_p;
 323                         }
 324                 }
 325                 count++;
 326                 argv++;
 327         }
 328
 329         if (p->iph.protocol == 0) {
 330                 if (memcmp(p->name, "gre", 3) == 0)
 331                         p->iph.protocol = IPPROTO_GRE;
 332                 else if (memcmp(p->name, "ipip", 4) == 0)
 333                         p->iph.protocol = IPPROTO_IPIP;
 334                 else if (memcmp(p->name, "sit", 3) == 0)
 335                         p->iph.protocol = IPPROTO_IPV6;
 336         }
 337
 338         if (p->iph.protocol == IPPROTO_IPIP || p->iph.protocol == IPPROTO_IPV6) {
 339                 if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {
 340                         bb_error_msg_and_die("keys are not allowed with ipip and sit");
 341                 }
 342         }
 343
 344         if (medium[0]) {
 345                 p->link = do_ioctl_get_ifindex(medium);
 346         }
 347
 348         if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 349                 p->i_key = p->iph.daddr;
 350                 p->i_flags |= GRE_KEY;
 351         }
 352         if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {
 353                 p->o_key = p->iph.daddr;
 354                 p->o_flags |= GRE_KEY;
 355         }
 356         if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {
 357                 bb_error_msg_and_die("broadcast tunnel requires a source address");
 358         }
 359 }
 360
 361 /* Return value becomes exitcode. It's okay to not return at all */
 362 static int do_add(int cmd, char **argv)
 363 {
 364         struct ip_tunnel_parm p;
 365
 366         parse_args(argv, cmd, &p);
 367
 368         if (p.iph.ttl && p.iph.frag_off == 0) {
 369                 bb_error_msg_and_die("ttl != 0 and noptmudisc are incompatible");
 370         }
 371
 372         switch (p.iph.protocol) {
 373         case IPPROTO_IPIP:
 374                 return do_add_ioctl(cmd, "tunl0", &p);
 375         case IPPROTO_GRE:
 376                 return do_add_ioctl(cmd, "gre0", &p);
 377         case IPPROTO_IPV6:
 378                 return do_add_ioctl(cmd, "sit0", &p);
 379         default:
 380                 bb_error_msg_and_die("cannot determine tunnel mode (ipip, gre or sit)");
 381         }
 382 }
 383
 384 /* Return value becomes exitcode. It's okay to not return at all */
 385 static int do_del(char **argv)
 386 {
 387         struct ip_tunnel_parm p;
 388
 389         parse_args(argv, SIOCDELTUNNEL, &p);
 390
 391         switch (p.iph.protocol) {
 392         case IPPROTO_IPIP:
 393                 return do_del_ioctl("tunl0", &p);
 394         case IPPROTO_GRE:
 395                 return do_del_ioctl("gre0", &p);
 396         case IPPROTO_IPV6:
 397                 return do_del_ioctl("sit0", &p);
 398         default:
 399                 return do_del_ioctl(p.name, &p);
 400         }
 401 }
 402
 403 static void print_tunnel(struct ip_tunnel_parm *p)
 404 {
 405         char s1[256];
 406         char s2[256];
 407         char s3[64];
 408         char s4[64];
 409
 410         format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1));
 411         format_host(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2));
 412         inet_ntop(AF_INET, &p->i_key, s3, sizeof(s3));
 413         inet_ntop(AF_INET, &p->o_key, s4, sizeof(s4));
 414
 415         printf("%s: %s/ip  remote %s  local %s ",
 416                p->name,
 417                p->iph.protocol == IPPROTO_IPIP ? "ip" :
 418                (p->iph.protocol == IPPROTO_GRE ? "gre" :
 419                 (p->iph.protocol == IPPROTO_IPV6 ? "ipv6" : "unknown")),
 420                p->iph.daddr ? s1 : "any", p->iph.saddr ? s2 : "any");
 421         if (p->link) {
 422                 char *n = do_ioctl_get_ifname(p->link);
 423                 if (n) {
 424                         printf(" dev %s ", n);
 425                         free(n);
 426                 }
 427         }
 428         if (p->iph.ttl)
 429                 printf(" ttl %d ", p->iph.ttl);
 430         else
 431                 printf(" ttl inherit ");
 432         if (p->iph.tos) {
 433                 SPRINT_BUF(b1);
 434                 printf(" tos");
 435                 if (p->iph.tos & 1)
 436                         printf(" inherit");
 437                 if (p->iph.tos & ~1)
 438                         printf("%c%s ", p->iph.tos & 1 ? '/' : ' ',
 439                                rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));
 440         }
 441         if (!(p->iph.frag_off & htons(IP_DF)))
 442                 printf(" nopmtudisc");
 443
 444         if ((p->i_flags & GRE_KEY) && (p->o_flags & GRE_KEY) && p->o_key == p->i_key)
 445                 printf(" key %s", s3);
 446         else if ((p->i_flags | p->o_flags) & GRE_KEY) {
 447                 if (p->i_flags & GRE_KEY)
 448                         printf(" ikey %s ", s3);
 449                 if (p->o_flags & GRE_KEY)
 450                         printf(" okey %s ", s4);
 451         }
 452
 453         if (p->i_flags & GRE_SEQ)
 454                 printf("%c  Drop packets out of sequence.\n", _SL_);
 455         if (p->i_flags & GRE_CSUM)
 456                 printf("%c  Checksum in received packet is required.", _SL_);
 457         if (p->o_flags & GRE_SEQ)
 458                 printf("%c  Sequence packets on output.", _SL_);
 459         if (p->o_flags & GRE_CSUM)
 460                 printf("%c  Checksum output packets.", _SL_);
 461 }
 462
 463 static void do_tunnels_list(struct ip_tunnel_parm *p)
 464 {
 465         char name[IFNAMSIZ];
 466         unsigned long rx_bytes, rx_packets, rx_errs, rx_drops,
 467                 rx_fifo, rx_frame,
 468                 tx_bytes, tx_packets, tx_errs, tx_drops,
 469                 tx_fifo, tx_colls, tx_carrier, rx_multi;
 470         int type;
 471         struct ip_tunnel_parm p1;
 472         char buf[512];
 473         FILE *fp = fopen_or_warn("/proc/net/dev", "r");
 474
 475         if (fp == NULL) {
 476                 return;
 477         }
 478         /* skip headers */
 479         fgets(buf, sizeof(buf), fp);
 480         fgets(buf, sizeof(buf), fp);
 481
 482         while (fgets(buf, sizeof(buf), fp) != NULL) {
 483                 char *ptr;
 484
 485                 /*buf[sizeof(buf) - 1] = 0; - fgets is safe anyway */
 486                 ptr = strchr(buf, ':');
 487                 if (ptr == NULL ||
 488                     (*ptr++ = 0, sscanf(buf, "%s", name) != 1)) {
 489                         bb_error_msg("wrong format of /proc/net/dev");
 490                         return;
 491                 }
 492                 if (sscanf(ptr, "%lu%lu%lu%lu%lu%lu%lu%*d%lu%lu%lu%lu%lu%lu%lu",
 493                            &rx_bytes, &rx_packets, &rx_errs, &rx_drops,
 494                            &rx_fifo, &rx_frame, &rx_multi,
 495                            &tx_bytes, &tx_packets, &tx_errs, &tx_drops,
 496                            &tx_fifo, &tx_colls, &tx_carrier) != 14)
 497                         continue;
 498                 if (p->name[0] && strcmp(p->name, name))
 499                         continue;
 500                 type = do_ioctl_get_iftype(name);
 501                 if (type == -1) {
 502                         bb_error_msg("cannot get type of [%s]", name);
 503                         continue;
 504                 }
 505                 if (type != ARPHRD_TUNNEL && type != ARPHRD_IPGRE && type != ARPHRD_SIT)
 506                         continue;
 507                 memset(&p1, 0, sizeof(p1));
 508                 if (do_get_ioctl(name, &p1))
 509                         continue;
 510                 if ((p->link && p1.link != p->link) ||
 511                     (p->name[0] && strcmp(p1.name, p->name)) ||
 512                     (p->iph.daddr && p1.iph.daddr != p->iph.daddr) ||
 513                     (p->iph.saddr && p1.iph.saddr != p->iph.saddr) ||
 514                     (p->i_key && p1.i_key != p->i_key))
 515                         continue;
 516                 print_tunnel(&p1);
 517                 bb_putchar('\n');
 518         }
 519 }
 520
 521 /* Return value becomes exitcode. It's okay to not return at all */
 522 static int do_show(char **argv)
 523 {
 524         int err;
 525         struct ip_tunnel_parm p;
 526
 527         parse_args(argv, SIOCGETTUNNEL, &p);
 528
 529         switch (p.iph.protocol) {
 530         case IPPROTO_IPIP:
 531                 err = do_get_ioctl(p.name[0] ? p.name : "tunl0", &p);
 532                 break;
 533         case IPPROTO_GRE:
 534                 err = do_get_ioctl(p.name[0] ? p.name : "gre0", &p);
 535                 break;
 536         case IPPROTO_IPV6:
 537                 err = do_get_ioctl(p.name[0] ? p.name : "sit0", &p);
 538                 break;
 539         default:
 540                 do_tunnels_list(&p);
 541                 return 0;
 542         }
 543         if (err)
 544                 return -1;
 545
 546         print_tunnel(&p);
 547         bb_putchar('\n');
 548         return 0;
 549 }
 550
 551 /* Return value becomes exitcode. It's okay to not return at all */
 552 int do_iptunnel(char **argv)
 553 {
 554         static const char keywords[] ALIGN1 =
 555                 "add\0""change\0""delete\0""show\0""list\0""lst\0";
 556         enum { ARG_add = 0, ARG_change, ARG_del, ARG_show, ARG_list, ARG_lst };
 557         int key;
 558
 559         if (*argv) {
 560                 key = index_in_substrings(keywords, *argv);
 561                 if (key < 0)
 562                         bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
 563                 argv++;
 564                 if (key == ARG_add)
 565                         return do_add(SIOCADDTUNNEL, argv);
 566                 if (key == ARG_change)
 567                         return do_add(SIOCCHGTUNNEL, argv);
 568                 if (key == ARG_del)
 569                         return do_del(argv);
 570         }
 571         return do_show(argv);
 572 }