git.oblomov.eu Git - linux-2.6/blob - net/ipv4/ip_options.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              The options processing module for ip.c
   7  *
   8  * Version:     $Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
   9  *
  10  * Authors:     A.N.Kuznetsov
  11  *
  12  */
  13
  14 #include <linux/capability.h>
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <asm/uaccess.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/ip.h>
  20 #include <linux/icmp.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/rtnetlink.h>
  23 #include <net/sock.h>
  24 #include <net/ip.h>
  25 #include <net/icmp.h>
  26 #include <net/route.h>
  27 #include <net/cipso_ipv4.h>
  28
  29 /*
  30  * Write options to IP header, record destination address to
  31  * source route option, address of outgoing interface
  32  * (we should already know it, so that this  function is allowed be
  33  * called only after routing decision) and timestamp,
  34  * if we originate this datagram.
  35  *
  36  * daddr is real destination address, next hop is recorded in IP header.
  37  * saddr is address of outgoing interface.
  38  */
  39
  40 void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
  41                             u32 daddr, struct rtable *rt, int is_frag)
  42 {
  43         unsigned char * iph = skb->nh.raw;
  44
  45         memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
  46         memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
  47         opt = &(IPCB(skb)->opt);
  48         opt->is_data = 0;
  49
  50         if (opt->srr)
  51                 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
  52
  53         if (!is_frag) {
  54                 if (opt->rr_needaddr)
  55                         ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
  56                 if (opt->ts_needaddr)
  57                         ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
  58                 if (opt->ts_needtime) {
  59                         struct timeval tv;
  60                         __u32 midtime;
  61                         do_gettimeofday(&tv);
  62                         midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
  63                         memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
  64                 }
  65                 return;
  66         }
  67         if (opt->rr) {
  68                 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
  69                 opt->rr = 0;
  70                 opt->rr_needaddr = 0;
  71         }
  72         if (opt->ts) {
  73                 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
  74                 opt->ts = 0;
  75                 opt->ts_needaddr = opt->ts_needtime = 0;
  76         }
  77 }
  78
  79 /*
  80  * Provided (sopt, skb) points to received options,
  81  * build in dopt compiled option set appropriate for answering.
  82  * i.e. invert SRR option, copy anothers,
  83  * and grab room in RR/TS options.
  84  *
  85  * NOTE: dopt cannot point to skb.
  86  */
  87
  88 int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
  89 {
  90         struct ip_options *sopt;
  91         unsigned char *sptr, *dptr;
  92         int soffset, doffset;
  93         int     optlen;
  94         u32     daddr;
  95
  96         memset(dopt, 0, sizeof(struct ip_options));
  97
  98         dopt->is_data = 1;
  99
 100         sopt = &(IPCB(skb)->opt);
 101
 102         if (sopt->optlen == 0) {
 103                 dopt->optlen = 0;
 104                 return 0;
 105         }
 106
 107         sptr = skb->nh.raw;
 108         dptr = dopt->__data;
 109
 110         if (skb->dst)
 111                 daddr = ((struct rtable*)skb->dst)->rt_spec_dst;
 112         else
 113                 daddr = skb->nh.iph->daddr;
 114
 115         if (sopt->rr) {
 116                 optlen  = sptr[sopt->rr+1];
 117                 soffset = sptr[sopt->rr+2];
 118                 dopt->rr = dopt->optlen + sizeof(struct iphdr);
 119                 memcpy(dptr, sptr+sopt->rr, optlen);
 120                 if (sopt->rr_needaddr && soffset <= optlen) {
 121                         if (soffset + 3 > optlen)
 122                                 return -EINVAL;
 123                         dptr[2] = soffset + 4;
 124                         dopt->rr_needaddr = 1;
 125                 }
 126                 dptr += optlen;
 127                 dopt->optlen += optlen;
 128         }
 129         if (sopt->ts) {
 130                 optlen = sptr[sopt->ts+1];
 131                 soffset = sptr[sopt->ts+2];
 132                 dopt->ts = dopt->optlen + sizeof(struct iphdr);
 133                 memcpy(dptr, sptr+sopt->ts, optlen);
 134                 if (soffset <= optlen) {
 135                         if (sopt->ts_needaddr) {
 136                                 if (soffset + 3 > optlen)
 137                                         return -EINVAL;
 138                                 dopt->ts_needaddr = 1;
 139                                 soffset += 4;
 140                         }
 141                         if (sopt->ts_needtime) {
 142                                 if (soffset + 3 > optlen)
 143                                         return -EINVAL;
 144                                 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
 145                                         dopt->ts_needtime = 1;
 146                                         soffset += 4;
 147                                 } else {
 148                                         dopt->ts_needtime = 0;
 149
 150                                         if (soffset + 8 <= optlen) {
 151                                                 __u32 addr;
 152
 153                                                 memcpy(&addr, sptr+soffset-1, 4);
 154                                                 if (inet_addr_type(addr) != RTN_LOCAL) {
 155                                                         dopt->ts_needtime = 1;
 156                                                         soffset += 8;
 157                                                 }
 158                                         }
 159                                 }
 160                         }
 161                         dptr[2] = soffset;
 162                 }
 163                 dptr += optlen;
 164                 dopt->optlen += optlen;
 165         }
 166         if (sopt->srr) {
 167                 unsigned char * start = sptr+sopt->srr;
 168                 u32 faddr;
 169
 170                 optlen  = start[1];
 171                 soffset = start[2];
 172                 doffset = 0;
 173                 if (soffset > optlen)
 174                         soffset = optlen + 1;
 175                 soffset -= 4;
 176                 if (soffset > 3) {
 177                         memcpy(&faddr, &start[soffset-1], 4);
 178                         for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
 179                                 memcpy(&dptr[doffset-1], &start[soffset-1], 4);
 180                         /*
 181                          * RFC1812 requires to fix illegal source routes.
 182                          */
 183                         if (memcmp(&skb->nh.iph->saddr, &start[soffset+3], 4) == 0)
 184                                 doffset -= 4;
 185                 }
 186                 if (doffset > 3) {
 187                         memcpy(&start[doffset-1], &daddr, 4);
 188                         dopt->faddr = faddr;
 189                         dptr[0] = start[0];
 190                         dptr[1] = doffset+3;
 191                         dptr[2] = 4;
 192                         dptr += doffset+3;
 193                         dopt->srr = dopt->optlen + sizeof(struct iphdr);
 194                         dopt->optlen += doffset+3;
 195                         dopt->is_strictroute = sopt->is_strictroute;
 196                 }
 197         }
 198         if (sopt->cipso) {
 199                 optlen  = sptr[sopt->cipso+1];
 200                 dopt->cipso = dopt->optlen+sizeof(struct iphdr);
 201                 memcpy(dptr, sptr+sopt->cipso, optlen);
 202                 dptr += optlen;
 203                 dopt->optlen += optlen;
 204         }
 205         while (dopt->optlen & 3) {
 206                 *dptr++ = IPOPT_END;
 207                 dopt->optlen++;
 208         }
 209         return 0;
 210 }
 211
 212 /*
 213  *      Options "fragmenting", just fill options not
 214  *      allowed in fragments with NOOPs.
 215  *      Simple and stupid 8), but the most efficient way.
 216  */
 217
 218 void ip_options_fragment(struct sk_buff * skb)
 219 {
 220         unsigned char * optptr = skb->nh.raw + sizeof(struct iphdr);
 221         struct ip_options * opt = &(IPCB(skb)->opt);
 222         int  l = opt->optlen;
 223         int  optlen;
 224
 225         while (l > 0) {
 226                 switch (*optptr) {
 227                 case IPOPT_END:
 228                         return;
 229                 case IPOPT_NOOP:
 230                         l--;
 231                         optptr++;
 232                         continue;
 233                 }
 234                 optlen = optptr[1];
 235                 if (optlen<2 || optlen>l)
 236                   return;
 237                 if (!IPOPT_COPIED(*optptr))
 238                         memset(optptr, IPOPT_NOOP, optlen);
 239                 l -= optlen;
 240                 optptr += optlen;
 241         }
 242         opt->ts = 0;
 243         opt->rr = 0;
 244         opt->rr_needaddr = 0;
 245         opt->ts_needaddr = 0;
 246         opt->ts_needtime = 0;
 247         return;
 248 }
 249
 250 /*
 251  * Verify options and fill pointers in struct options.
 252  * Caller should clear *opt, and set opt->data.
 253  * If opt == NULL, then skb->data should point to IP header.
 254  */
 255
 256 int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
 257 {
 258         int l;
 259         unsigned char * iph;
 260         unsigned char * optptr;
 261         int optlen;
 262         unsigned char * pp_ptr = NULL;
 263         struct rtable *rt = skb ? (struct rtable*)skb->dst : NULL;
 264
 265         if (!opt) {
 266                 opt = &(IPCB(skb)->opt);
 267                 iph = skb->nh.raw;
 268                 opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
 269                 optptr = iph + sizeof(struct iphdr);
 270                 opt->is_data = 0;
 271         } else {
 272                 optptr = opt->is_data ? opt->__data : (unsigned char*)&(skb->nh.iph[1]);
 273                 iph = optptr - sizeof(struct iphdr);
 274         }
 275
 276         for (l = opt->optlen; l > 0; ) {
 277                 switch (*optptr) {
 278                       case IPOPT_END:
 279                         for (optptr++, l--; l>0; optptr++, l--) {
 280                                 if (*optptr != IPOPT_END) {
 281                                         *optptr = IPOPT_END;
 282                                         opt->is_changed = 1;
 283                                 }
 284                         }
 285                         goto eol;
 286                       case IPOPT_NOOP:
 287                         l--;
 288                         optptr++;
 289                         continue;
 290                 }
 291                 optlen = optptr[1];
 292                 if (optlen<2 || optlen>l) {
 293                         pp_ptr = optptr;
 294                         goto error;
 295                 }
 296                 switch (*optptr) {
 297                       case IPOPT_SSRR:
 298                       case IPOPT_LSRR:
 299                         if (optlen < 3) {
 300                                 pp_ptr = optptr + 1;
 301                                 goto error;
 302                         }
 303                         if (optptr[2] < 4) {
 304                                 pp_ptr = optptr + 2;
 305                                 goto error;
 306                         }
 307                         /* NB: cf RFC-1812 5.2.4.1 */
 308                         if (opt->srr) {
 309                                 pp_ptr = optptr;
 310                                 goto error;
 311                         }
 312                         if (!skb) {
 313                                 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
 314                                         pp_ptr = optptr + 1;
 315                                         goto error;
 316                                 }
 317                                 memcpy(&opt->faddr, &optptr[3], 4);
 318                                 if (optlen > 7)
 319                                         memmove(&optptr[3], &optptr[7], optlen-7);
 320                         }
 321                         opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
 322                         opt->srr = optptr - iph;
 323                         break;
 324                       case IPOPT_RR:
 325                         if (opt->rr) {
 326                                 pp_ptr = optptr;
 327                                 goto error;
 328                         }
 329                         if (optlen < 3) {
 330                                 pp_ptr = optptr + 1;
 331                                 goto error;
 332                         }
 333                         if (optptr[2] < 4) {
 334                                 pp_ptr = optptr + 2;
 335                                 goto error;
 336                         }
 337                         if (optptr[2] <= optlen) {
 338                                 if (optptr[2]+3 > optlen) {
 339                                         pp_ptr = optptr + 2;
 340                                         goto error;
 341                                 }
 342                                 if (skb) {
 343                                         memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
 344                                         opt->is_changed = 1;
 345                                 }
 346                                 optptr[2] += 4;
 347                                 opt->rr_needaddr = 1;
 348                         }
 349                         opt->rr = optptr - iph;
 350                         break;
 351                       case IPOPT_TIMESTAMP:
 352                         if (opt->ts) {
 353                                 pp_ptr = optptr;
 354                                 goto error;
 355                         }
 356                         if (optlen < 4) {
 357                                 pp_ptr = optptr + 1;
 358                                 goto error;
 359                         }
 360                         if (optptr[2] < 5) {
 361                                 pp_ptr = optptr + 2;
 362                                 goto error;
 363                         }
 364                         if (optptr[2] <= optlen) {
 365                                 __u32 * timeptr = NULL;
 366                                 if (optptr[2]+3 > optptr[1]) {
 367                                         pp_ptr = optptr + 2;
 368                                         goto error;
 369                                 }
 370                                 switch (optptr[3]&0xF) {
 371                                       case IPOPT_TS_TSONLY:
 372                                         opt->ts = optptr - iph;
 373                                         if (skb)
 374                                                 timeptr = (__u32*)&optptr[optptr[2]-1];
 375                                         opt->ts_needtime = 1;
 376                                         optptr[2] += 4;
 377                                         break;
 378                                       case IPOPT_TS_TSANDADDR:
 379                                         if (optptr[2]+7 > optptr[1]) {
 380                                                 pp_ptr = optptr + 2;
 381                                                 goto error;
 382                                         }
 383                                         opt->ts = optptr - iph;
 384                                         if (skb) {
 385                                                 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
 386                                                 timeptr = (__u32*)&optptr[optptr[2]+3];
 387                                         }
 388                                         opt->ts_needaddr = 1;
 389                                         opt->ts_needtime = 1;
 390                                         optptr[2] += 8;
 391                                         break;
 392                                       case IPOPT_TS_PRESPEC:
 393                                         if (optptr[2]+7 > optptr[1]) {
 394                                                 pp_ptr = optptr + 2;
 395                                                 goto error;
 396                                         }
 397                                         opt->ts = optptr - iph;
 398                                         {
 399                                                 u32 addr;
 400                                                 memcpy(&addr, &optptr[optptr[2]-1], 4);
 401                                                 if (inet_addr_type(addr) == RTN_UNICAST)
 402                                                         break;
 403                                                 if (skb)
 404                                                         timeptr = (__u32*)&optptr[optptr[2]+3];
 405                                         }
 406                                         opt->ts_needtime = 1;
 407                                         optptr[2] += 8;
 408                                         break;
 409                                       default:
 410                                         if (!skb && !capable(CAP_NET_RAW)) {
 411                                                 pp_ptr = optptr + 3;
 412                                                 goto error;
 413                                         }
 414                                         break;
 415                                 }
 416                                 if (timeptr) {
 417                                         struct timeval tv;
 418                                         __u32  midtime;
 419                                         do_gettimeofday(&tv);
 420                                         midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
 421                                         memcpy(timeptr, &midtime, sizeof(__u32));
 422                                         opt->is_changed = 1;
 423                                 }
 424                         } else {
 425                                 unsigned overflow = optptr[3]>>4;
 426                                 if (overflow == 15) {
 427                                         pp_ptr = optptr + 3;
 428                                         goto error;
 429                                 }
 430                                 opt->ts = optptr - iph;
 431                                 if (skb) {
 432                                         optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
 433                                         opt->is_changed = 1;
 434                                 }
 435                         }
 436                         break;
 437                       case IPOPT_RA:
 438                         if (optlen < 4) {
 439                                 pp_ptr = optptr + 1;
 440                                 goto error;
 441                         }
 442                         if (optptr[2] == 0 && optptr[3] == 0)
 443                                 opt->router_alert = optptr - iph;
 444                         break;
 445                       case IPOPT_CIPSO:
 446                         if (opt->cipso) {
 447                                 pp_ptr = optptr;
 448                                 goto error;
 449                         }
 450                         opt->cipso = optptr - iph;
 451                         if (cipso_v4_validate(&optptr)) {
 452                                 pp_ptr = optptr;
 453                                 goto error;
 454                         }
 455                         break;
 456                       case IPOPT_SEC:
 457                       case IPOPT_SID:
 458                       default:
 459                         if (!skb && !capable(CAP_NET_RAW)) {
 460                                 pp_ptr = optptr;
 461                                 goto error;
 462                         }
 463                         break;
 464                 }
 465                 l -= optlen;
 466                 optptr += optlen;
 467         }
 468
 469 eol:
 470         if (!pp_ptr)
 471                 return 0;
 472
 473 error:
 474         if (skb) {
 475                 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
 476         }
 477         return -EINVAL;
 478 }
 479
 480
 481 /*
 482  *      Undo all the changes done by ip_options_compile().
 483  */
 484
 485 void ip_options_undo(struct ip_options * opt)
 486 {
 487         if (opt->srr) {
 488                 unsigned  char * optptr = opt->__data+opt->srr-sizeof(struct  iphdr);
 489                 memmove(optptr+7, optptr+3, optptr[1]-7);
 490                 memcpy(optptr+3, &opt->faddr, 4);
 491         }
 492         if (opt->rr_needaddr) {
 493                 unsigned  char * optptr = opt->__data+opt->rr-sizeof(struct  iphdr);
 494                 optptr[2] -= 4;
 495                 memset(&optptr[optptr[2]-1], 0, 4);
 496         }
 497         if (opt->ts) {
 498                 unsigned  char * optptr = opt->__data+opt->ts-sizeof(struct  iphdr);
 499                 if (opt->ts_needtime) {
 500                         optptr[2] -= 4;
 501                         memset(&optptr[optptr[2]-1], 0, 4);
 502                         if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
 503                                 optptr[2] -= 4;
 504                 }
 505                 if (opt->ts_needaddr) {
 506                         optptr[2] -= 4;
 507                         memset(&optptr[optptr[2]-1], 0, 4);
 508                 }
 509         }
 510 }
 511
 512 static struct ip_options *ip_options_get_alloc(const int optlen)
 513 {
 514         struct ip_options *opt = kmalloc(sizeof(*opt) + ((optlen + 3) & ~3),
 515                                          GFP_KERNEL);
 516         if (opt)
 517                 memset(opt, 0, sizeof(*opt));
 518         return opt;
 519 }
 520
 521 static int ip_options_get_finish(struct ip_options **optp,
 522                                  struct ip_options *opt, int optlen)
 523 {
 524         while (optlen & 3)
 525                 opt->__data[optlen++] = IPOPT_END;
 526         opt->optlen = optlen;
 527         opt->is_data = 1;
 528         if (optlen && ip_options_compile(opt, NULL)) {
 529                 kfree(opt);
 530                 return -EINVAL;
 531         }
 532         kfree(*optp);
 533         *optp = opt;
 534         return 0;
 535 }
 536
 537 int ip_options_get_from_user(struct ip_options **optp, unsigned char __user *data, int optlen)
 538 {
 539         struct ip_options *opt = ip_options_get_alloc(optlen);
 540
 541         if (!opt)
 542                 return -ENOMEM;
 543         if (optlen && copy_from_user(opt->__data, data, optlen)) {
 544                 kfree(opt);
 545                 return -EFAULT;
 546         }
 547         return ip_options_get_finish(optp, opt, optlen);
 548 }
 549
 550 int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen)
 551 {
 552         struct ip_options *opt = ip_options_get_alloc(optlen);
 553
 554         if (!opt)
 555                 return -ENOMEM;
 556         if (optlen)
 557                 memcpy(opt->__data, data, optlen);
 558         return ip_options_get_finish(optp, opt, optlen);
 559 }
 560
 561 void ip_forward_options(struct sk_buff *skb)
 562 {
 563         struct   ip_options * opt       = &(IPCB(skb)->opt);
 564         unsigned char * optptr;
 565         struct rtable *rt = (struct rtable*)skb->dst;
 566         unsigned char *raw = skb->nh.raw;
 567
 568         if (opt->rr_needaddr) {
 569                 optptr = (unsigned char *)raw + opt->rr;
 570                 ip_rt_get_source(&optptr[optptr[2]-5], rt);
 571                 opt->is_changed = 1;
 572         }
 573         if (opt->srr_is_hit) {
 574                 int srrptr, srrspace;
 575
 576                 optptr = raw + opt->srr;
 577
 578                 for ( srrptr=optptr[2], srrspace = optptr[1];
 579                      srrptr <= srrspace;
 580                      srrptr += 4
 581                      ) {
 582                         if (srrptr + 3 > srrspace)
 583                                 break;
 584                         if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
 585                                 break;
 586                 }
 587                 if (srrptr + 3 <= srrspace) {
 588                         opt->is_changed = 1;
 589                         ip_rt_get_source(&optptr[srrptr-1], rt);
 590                         skb->nh.iph->daddr = rt->rt_dst;
 591                         optptr[2] = srrptr+4;
 592                 } else if (net_ratelimit())
 593                         printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
 594                 if (opt->ts_needaddr) {
 595                         optptr = raw + opt->ts;
 596                         ip_rt_get_source(&optptr[optptr[2]-9], rt);
 597                         opt->is_changed = 1;
 598                 }
 599         }
 600         if (opt->is_changed) {
 601                 opt->is_changed = 0;
 602                 ip_send_check(skb->nh.iph);
 603         }
 604 }
 605
 606 int ip_options_rcv_srr(struct sk_buff *skb)
 607 {
 608         struct ip_options *opt = &(IPCB(skb)->opt);
 609         int srrspace, srrptr;
 610         u32 nexthop;
 611         struct iphdr *iph = skb->nh.iph;
 612         unsigned char * optptr = skb->nh.raw + opt->srr;
 613         struct rtable *rt = (struct rtable*)skb->dst;
 614         struct rtable *rt2;
 615         int err;
 616
 617         if (!opt->srr)
 618                 return 0;
 619
 620         if (skb->pkt_type != PACKET_HOST)
 621                 return -EINVAL;
 622         if (rt->rt_type == RTN_UNICAST) {
 623                 if (!opt->is_strictroute)
 624                         return 0;
 625                 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
 626                 return -EINVAL;
 627         }
 628         if (rt->rt_type != RTN_LOCAL)
 629                 return -EINVAL;
 630
 631         for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
 632                 if (srrptr + 3 > srrspace) {
 633                         icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
 634                         return -EINVAL;
 635                 }
 636                 memcpy(&nexthop, &optptr[srrptr-1], 4);
 637
 638                 rt = (struct rtable*)skb->dst;
 639                 skb->dst = NULL;
 640                 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
 641                 rt2 = (struct rtable*)skb->dst;
 642                 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
 643                         ip_rt_put(rt2);
 644                         skb->dst = &rt->u.dst;
 645                         return -EINVAL;
 646                 }
 647                 ip_rt_put(rt);
 648                 if (rt2->rt_type != RTN_LOCAL)
 649                         break;
 650                 /* Superfast 8) loopback forward */
 651                 memcpy(&iph->daddr, &optptr[srrptr-1], 4);
 652                 opt->is_changed = 1;
 653         }
 654         if (srrptr <= srrspace) {
 655                 opt->srr_is_hit = 1;
 656                 opt->is_changed = 1;
 657         }
 658         return 0;
 659 }