/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * The options processing module for ip.c * * Version: $Id: ip_options.c,v 1.20 2000/08/09 09:17:00 davem Exp $ * * Authors: A.N.Kuznetsov * */ #include <linux/types.h> #include <asm/uaccess.h> #include <linux/skbuff.h> #include <linux/ip.h> #include <linux/icmp.h> #include <linux/netdevice.h> #include <linux/rtnetlink.h> #include <net/sock.h> #include <net/ip.h> #include <net/icmp.h> /* * Write options to IP header, record destination address to * source route option, address of outgoing interface * (we should already know it, so that this function is allowed be * called only after routing decision) and timestamp, * if we originate this datagram. * * daddr is real destination address, next hop is recorded in IP header. * saddr is address of outgoing interface. */ 36 void ip_options_build(struct sk_buff * skb, struct ip_options * opt, u32 daddr, struct rtable *rt, int is_frag) { unsigned char * iph = skb->nh.raw; memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options)); memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen); opt = &(IPCB(skb)->opt); opt->is_data = 0; 46 if (opt->srr) memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4); 49 if (!is_frag) { 50 if (opt->rr_needaddr) ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt); 52 if (opt->ts_needaddr) ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt); 54 if (opt->ts_needtime) { struct timeval tv; __u32 midtime; do_gettimeofday(&tv); midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000); memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4); } 61 return; } 63 if (opt->rr) { memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]); opt->rr = 0; opt->rr_needaddr = 0; } 68 if (opt->ts) { memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]); opt->ts = 0; opt->ts_needaddr = opt->ts_needtime = 0; } } /* * Provided (sopt, skb) points to received options, * build in dopt compiled option set appropriate for answering. * i.e. invert SRR option, copy anothers, * and grab room in RR/TS options. * * NOTE: dopt cannot point to skb. */ 84 int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb) { struct ip_options *sopt; unsigned char *sptr, *dptr; int soffset, doffset; int optlen; u32 daddr; memset(dopt, 0, sizeof(struct ip_options)); dopt->is_data = 1; sopt = &(IPCB(skb)->opt); 98 if (sopt->optlen == 0) { dopt->optlen = 0; 100 return 0; } sptr = skb->nh.raw; dptr = dopt->__data; 106 if (skb->dst) daddr = ((struct rtable*)skb->dst)->rt_spec_dst; 108 else daddr = skb->nh.iph->daddr; 111 if (sopt->rr) { optlen = sptr[sopt->rr+1]; soffset = sptr[sopt->rr+2]; dopt->rr = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->rr, optlen); 116 if (sopt->rr_needaddr && soffset <= optlen) { 117 if (soffset + 3 > optlen) 118 return -EINVAL; dptr[2] = soffset + 4; dopt->rr_needaddr = 1; } dptr += optlen; dopt->optlen += optlen; } 125 if (sopt->ts) { optlen = sptr[sopt->ts+1]; soffset = sptr[sopt->ts+2]; dopt->ts = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->ts, optlen); 130 if (soffset <= optlen) { 131 if (sopt->ts_needaddr) { 132 if (soffset + 3 > optlen) 133 return -EINVAL; dopt->ts_needaddr = 1; soffset += 4; } 137 if (sopt->ts_needtime) { 138 if (soffset + 3 > optlen) 139 return -EINVAL; 140 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) { dopt->ts_needtime = 1; soffset += 4; 143 } else { dopt->ts_needtime = 0; 146 if (soffset + 8 <= optlen) { __u32 addr; memcpy(&addr, sptr+soffset-1, 4); 150 if (inet_addr_type(addr) != RTN_LOCAL) { dopt->ts_needtime = 1; soffset += 8; } } } } dptr[2] = soffset; } dptr += optlen; dopt->optlen += optlen; } 162 if (sopt->srr) { unsigned char * start = sptr+sopt->srr; u32 faddr; optlen = start[1]; soffset = start[2]; doffset = 0; 169 if (soffset > optlen) soffset = optlen + 1; soffset -= 4; 172 if (soffset > 3) { memcpy(&faddr, &start[soffset-1], 4); 174 for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4) memcpy(&dptr[doffset-1], &start[soffset-1], 4); /* * RFC1812 requires to fix illegal source routes. */ 179 if (memcmp(&skb->nh.iph->saddr, &start[soffset+3], 4) == 0) doffset -= 4; } 182 if (doffset > 3) { memcpy(&start[doffset-1], &daddr, 4); dopt->faddr = faddr; dptr[0] = start[0]; dptr[1] = doffset+3; dptr[2] = 4; dptr += doffset+3; dopt->srr = dopt->optlen + sizeof(struct iphdr); dopt->optlen += doffset+3; dopt->is_strictroute = sopt->is_strictroute; } } 194 while (dopt->optlen & 3) { *dptr++ = IPOPT_END; dopt->optlen++; } 198 return 0; } /* * Options "fragmenting", just fill options not * allowed in fragments with NOOPs. * Simple and stupid 8), but the most efficient way. */ 207 void ip_options_fragment(struct sk_buff * skb) { unsigned char * optptr = skb->nh.raw; struct ip_options * opt = &(IPCB(skb)->opt); int l = opt->optlen; int optlen; 214 while (l > 0) { 215 switch (*optptr) { 216 case IPOPT_END: 217 return; 218 case IPOPT_NOOP: l--; optptr++; 221 continue; } optlen = optptr[1]; 224 if (optlen<2 || optlen>l) 225 return; 226 if (!IPOPT_COPIED(*optptr)) memset(optptr, IPOPT_NOOP, optlen); l -= optlen; optptr += optlen; } opt->ts = 0; opt->rr = 0; opt->rr_needaddr = 0; opt->ts_needaddr = 0; opt->ts_needtime = 0; 236 return; } /* * Verify options and fill pointers in struct options. * Caller should clear *opt, and set opt->data. * If opt == NULL, then skb->data should point to IP header. */ 245 int ip_options_compile(struct ip_options * opt, struct sk_buff * skb) { int l; unsigned char * iph; unsigned char * optptr; int optlen; unsigned char * pp_ptr = NULL; struct rtable *rt = skb ? (struct rtable*)skb->dst : NULL; 254 if (!opt) { opt = &(IPCB(skb)->opt); memset(opt, 0, sizeof(struct ip_options)); iph = skb->nh.raw; opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr); optptr = iph + sizeof(struct iphdr); opt->is_data = 0; 261 } else { optptr = opt->is_data ? opt->__data : (unsigned char*)&(skb->nh.iph[1]); iph = optptr - sizeof(struct iphdr); } 266 for (l = opt->optlen; l > 0; ) { 267 switch (*optptr) { 268 case IPOPT_END: 269 for (optptr++, l--; l>0; l--) { 270 if (*optptr != IPOPT_END) { *optptr = IPOPT_END; opt->is_changed = 1; } } 275 goto eol; 276 case IPOPT_NOOP: l--; optptr++; 279 continue; } optlen = optptr[1]; 282 if (optlen<2 || optlen>l) { pp_ptr = optptr; 284 goto error; } 286 switch (*optptr) { 287 case IPOPT_SSRR: 288 case IPOPT_LSRR: 289 if (optlen < 3) { pp_ptr = optptr + 1; 291 goto error; } 293 if (optptr[2] < 4) { pp_ptr = optptr + 2; 295 goto error; } /* NB: cf RFC-1812 5.2.4.1 */ 298 if (opt->srr) { pp_ptr = optptr; 300 goto error; } 302 if (!skb) { 303 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) { pp_ptr = optptr + 1; 305 goto error; } memcpy(&opt->faddr, &optptr[3], 4); 308 if (optlen > 7) memmove(&optptr[3], &optptr[7], optlen-7); } opt->is_strictroute = (optptr[0] == IPOPT_SSRR); opt->srr = optptr - iph; 313 break; 314 case IPOPT_RR: 315 if (opt->rr) { pp_ptr = optptr; 317 goto error; } 319 if (optlen < 3) { pp_ptr = optptr + 1; 321 goto error; } 323 if (optptr[2] < 4) { pp_ptr = optptr + 2; 325 goto error; } 327 if (optptr[2] <= optlen) { 328 if (optptr[2]+3 > optlen) { pp_ptr = optptr + 2; 330 goto error; } 332 if (skb) { memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); opt->is_changed = 1; } optptr[2] += 4; opt->rr_needaddr = 1; } opt->rr = optptr - iph; 340 break; 341 case IPOPT_TIMESTAMP: 342 if (opt->ts) { pp_ptr = optptr; 344 goto error; } 346 if (optlen < 4) { pp_ptr = optptr + 1; 348 goto error; } 350 if (optptr[2] < 5) { pp_ptr = optptr + 2; 352 goto error; } 354 if (optptr[2] <= optlen) { __u32 * timeptr = NULL; 356 if (optptr[2]+3 > optptr[1]) { pp_ptr = optptr + 2; 358 goto error; } 360 switch (optptr[3]&0xF) { 361 case IPOPT_TS_TSONLY: opt->ts = optptr - iph; 363 if (skb) timeptr = (__u32*)&optptr[optptr[2]-1]; opt->ts_needtime = 1; optptr[2] += 4; 367 break; 368 case IPOPT_TS_TSANDADDR: 369 if (optptr[2]+7 > optptr[1]) { pp_ptr = optptr + 2; 371 goto error; } opt->ts = optptr - iph; 374 if (skb) { memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); timeptr = (__u32*)&optptr[optptr[2]+3]; } opt->ts_needaddr = 1; opt->ts_needtime = 1; optptr[2] += 8; 381 break; 382 case IPOPT_TS_PRESPEC: 383 if (optptr[2]+7 > optptr[1]) { pp_ptr = optptr + 2; 385 goto error; } opt->ts = optptr - iph; { u32 addr; memcpy(&addr, &optptr[optptr[2]-1], 4); 391 if (inet_addr_type(addr) == RTN_UNICAST) 392 break; 393 if (skb) timeptr = (__u32*)&optptr[optptr[2]+3]; } opt->ts_needtime = 1; optptr[2] += 8; 398 break; 399 default: 400 if (!skb && !capable(CAP_NET_RAW)) { pp_ptr = optptr + 3; 402 goto error; } 404 break; } 406 if (timeptr) { struct timeval tv; __u32 midtime; do_gettimeofday(&tv); midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000); memcpy(timeptr, &midtime, sizeof(__u32)); opt->is_changed = 1; } 414 } else { unsigned overflow = optptr[3]>>4; 416 if (overflow == 15) { pp_ptr = optptr + 3; 418 goto error; } opt->ts = optptr - iph; 421 if (skb) { optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4); opt->is_changed = 1; } } 426 break; 427 case IPOPT_RA: 428 if (optlen < 4) { pp_ptr = optptr + 1; 430 goto error; } 432 if (optptr[2] == 0 && optptr[3] == 0) opt->router_alert = optptr - iph; 434 break; 435 case IPOPT_SEC: 436 case IPOPT_SID: 437 default: 438 if (!skb && !capable(CAP_NET_RAW)) { pp_ptr = optptr; 440 goto error; } 442 break; } l -= optlen; optptr += optlen; } eol: 449 if (!pp_ptr) 450 return 0; error: 453 if (skb) { icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24)); } 456 return -EINVAL; } /* * Undo all the changes done by ip_options_compile(). */ 464 void ip_options_undo(struct ip_options * opt) { 466 if (opt->srr) { unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr); memmove(optptr+7, optptr+3, optptr[1]-7); memcpy(optptr+3, &opt->faddr, 4); } 471 if (opt->rr_needaddr) { unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr); optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); } 476 if (opt->ts) { unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr); 478 if (opt->ts_needtime) { optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); 481 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC) optptr[2] -= 4; } 484 if (opt->ts_needaddr) { optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); } } } 491 int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user) { struct ip_options *opt; opt = kmalloc(sizeof(struct ip_options)+((optlen+3)&~3), GFP_KERNEL); 496 if (!opt) 497 return -ENOMEM; memset(opt, 0, sizeof(struct ip_options)); 499 if (optlen) { 500 if (user) { 501 if (copy_from_user(opt->__data, data, optlen)) { kfree(opt); 503 return -EFAULT; } 505 } else memcpy(opt->__data, data, optlen); } 508 while (optlen & 3) opt->__data[optlen++] = IPOPT_END; opt->optlen = optlen; opt->is_data = 1; opt->is_setbyuser = 1; 513 if (optlen && ip_options_compile(opt, NULL)) { kfree(opt); 515 return -EINVAL; } *optp = opt; 518 return 0; } 521 void ip_forward_options(struct sk_buff *skb) { struct ip_options * opt = &(IPCB(skb)->opt); unsigned char * optptr; struct rtable *rt = (struct rtable*)skb->dst; unsigned char *raw = skb->nh.raw; 528 if (opt->rr_needaddr) { optptr = (unsigned char *)raw + opt->rr; ip_rt_get_source(&optptr[optptr[2]-5], rt); opt->is_changed = 1; } 533 if (opt->srr_is_hit) { int srrptr, srrspace; optptr = raw + opt->srr; for ( srrptr=optptr[2], srrspace = optptr[1]; 539 srrptr <= srrspace; srrptr += 4 ) { 542 if (srrptr + 3 > srrspace) 543 break; 544 if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0) 545 break; } 547 if (srrptr + 3 <= srrspace) { opt->is_changed = 1; ip_rt_get_source(&optptr[srrptr-1], rt); skb->nh.iph->daddr = rt->rt_dst; optptr[2] = srrptr+4; 552 } else printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n"); 554 if (opt->ts_needaddr) { optptr = raw + opt->ts; ip_rt_get_source(&optptr[optptr[2]-9], rt); opt->is_changed = 1; } } 560 if (opt->is_changed) { opt->is_changed = 0; ip_send_check(skb->nh.iph); } } 566 int ip_options_rcv_srr(struct sk_buff *skb) { struct ip_options *opt = &(IPCB(skb)->opt); int srrspace, srrptr; u32 nexthop; struct iphdr *iph = skb->nh.iph; unsigned char * optptr = skb->nh.raw + opt->srr; struct rtable *rt = (struct rtable*)skb->dst; struct rtable *rt2; int err; 577 if (!opt->srr) 578 return 0; 580 if (skb->pkt_type != PACKET_HOST) 581 return -EINVAL; 582 if (rt->rt_type == RTN_UNICAST) { 583 if (!opt->is_strictroute) 584 return 0; icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24)); 586 return -EINVAL; } 588 if (rt->rt_type != RTN_LOCAL) 589 return -EINVAL; 591 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) { 592 if (srrptr + 3 > srrspace) { icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24)); 594 return -EINVAL; } memcpy(&nexthop, &optptr[srrptr-1], 4); rt = (struct rtable*)skb->dst; skb->dst = NULL; err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev); rt2 = (struct rtable*)skb->dst; 602 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) { ip_rt_put(rt2); skb->dst = &rt->u.dst; 605 return -EINVAL; } ip_rt_put(rt); 608 if (rt2->rt_type != RTN_LOCAL) 609 break; /* Superfast 8) loopback forward */ memcpy(&iph->daddr, &optptr[srrptr-1], 4); opt->is_changed = 1; } 614 if (srrptr <= srrspace) { opt->srr_is_hit = 1; opt->is_changed = 1; } 618 return 0; }