1 /* 2 * IPv6 output functions 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $ 9 * 10 * Based on linux/net/ipv4/ip_output.c 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Changes: 18 * A.N.Kuznetsov : airthmetics in fragmentation. 19 * extension headers are implemented. 20 * route changes now work. 21 * ip6_forward does not confuse sniffers. 22 * etc. 23 * 24 * H. von Brand : Added missing #include <linux/string.h> 25 * Imran Patel : frag id should be in NBO 26 * Kazunori MIYAZAWA @USAGI 27 * : add ip6_append_data and related functions 28 * for datagram xmit 29 */ 30 31 #include <linux/config.h> 32 #include <linux/errno.h> 33 #include <linux/types.h> 34 #include <linux/string.h> 35 #include <linux/socket.h> 36 #include <linux/net.h> 37 #include <linux/netdevice.h> 38 #include <linux/if_arp.h> 39 #include <linux/in6.h> 40 #include <linux/tcp.h> 41 #include <linux/route.h> 42 #include <linux/module.h> 43 44 #include <linux/netfilter.h> 45 #include <linux/netfilter_ipv6.h> 46 47 #include <net/sock.h> 48 #include <net/snmp.h> 49 50 #include <net/ipv6.h> 51 #include <net/ndisc.h> 52 #include <net/protocol.h> 53 #include <net/ip6_route.h> 54 #include <net/addrconf.h> 55 #include <net/rawv6.h> 56 #include <net/icmp.h> 57 #include <net/xfrm.h> 58 #include <net/checksum.h> 59 60 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)); 61 62 static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr) 63 { 64 static u32 ipv6_fragmentation_id = 1; 65 static DEFINE_SPINLOCK(ip6_id_lock); 66 67 spin_lock_bh(&ip6_id_lock); 68 fhdr->identification = htonl(ipv6_fragmentation_id); 69 if (++ipv6_fragmentation_id == 0) 70 ipv6_fragmentation_id = 1; 71 spin_unlock_bh(&ip6_id_lock); 72 } 73 74 static inline int ip6_output_finish(struct sk_buff *skb) 75 { 76 77 struct dst_entry *dst = skb->dst; 78 struct hh_cache *hh = dst->hh; 79 80 if (hh) { 81 int hh_alen; 82 83 read_lock_bh(&hh->hh_lock); 84 hh_alen = HH_DATA_ALIGN(hh->hh_len); 85 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 86 read_unlock_bh(&hh->hh_lock); 87 skb_push(skb, hh->hh_len); 88 return hh->hh_output(skb); 89 } else if (dst->neighbour) 90 return dst->neighbour->output(skb); 91 92 IP6_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); 93 kfree_skb(skb); 94 return -EINVAL; 95 96 } 97 98 /* dev_loopback_xmit for use with netfilter. */ 99 static int ip6_dev_loopback_xmit(struct sk_buff *newskb) 100 { 101 newskb->mac.raw = newskb->data; 102 __skb_pull(newskb, newskb->nh.raw - newskb->data); 103 newskb->pkt_type = PACKET_LOOPBACK; 104 newskb->ip_summed = CHECKSUM_UNNECESSARY; 105 BUG_TRAP(newskb->dst); 106 107 netif_rx(newskb); 108 return 0; 109 } 110 111 112 static int ip6_output2(struct sk_buff *skb) 113 { 114 struct dst_entry *dst = skb->dst; 115 struct net_device *dev = dst->dev; 116 117 skb->protocol = htons(ETH_P_IPV6); 118 skb->dev = dev; 119 120 if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr)) { 121 struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL; 122 123 if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) && 124 ipv6_chk_mcast_addr(dev, &skb->nh.ipv6h->daddr, 125 &skb->nh.ipv6h->saddr)) { 126 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 127 128 /* Do not check for IFF_ALLMULTI; multicast routing 129 is not supported in any case. 130 */ 131 if (newskb) 132 NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL, 133 newskb->dev, 134 ip6_dev_loopback_xmit); 135 136 if (skb->nh.ipv6h->hop_limit == 0) { 137 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 138 kfree_skb(skb); 139 return 0; 140 } 141 } 142 143 IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS); 144 } 145 146 return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish); 147 } 148 149 int ip6_output(struct sk_buff *skb) 150 { 151 if ((skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->gso_size) || 152 dst_allfrag(skb->dst)) 153 return ip6_fragment(skb, ip6_output2); 154 else 155 return ip6_output2(skb); 156 } 157 158 /* 159 * xmit an sk_buff (used by TCP) 160 */ 161 162 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, 163 struct ipv6_txoptions *opt, int ipfragok) 164 { 165 struct ipv6_pinfo *np = inet6_sk(sk); 166 struct in6_addr *first_hop = &fl->fl6_dst; 167 struct dst_entry *dst = skb->dst; 168 struct ipv6hdr *hdr; 169 u8 proto = fl->proto; 170 int seg_len = skb->len; 171 int hlimit, tclass; 172 u32 mtu; 173 174 if (opt) { 175 int head_room; 176 177 /* First: exthdrs may take lots of space (~8K for now) 178 MAX_HEADER is not enough. 179 */ 180 head_room = opt->opt_nflen + opt->opt_flen; 181 seg_len += head_room; 182 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 183 184 if (skb_headroom(skb) < head_room) { 185 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 186 kfree_skb(skb); 187 skb = skb2; 188 if (skb == NULL) { 189 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 190 return -ENOBUFS; 191 } 192 if (sk) 193 skb_set_owner_w(skb, sk); 194 } 195 if (opt->opt_flen) 196 ipv6_push_frag_opts(skb, opt, &proto); 197 if (opt->opt_nflen) 198 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 199 } 200 201 hdr = skb->nh.ipv6h = (struct ipv6hdr*)skb_push(skb, sizeof(struct ipv6hdr)); 202 203 /* 204 * Fill in the IPv6 header 205 */ 206 207 hlimit = -1; 208 if (np) 209 hlimit = np->hop_limit; 210 if (hlimit < 0) 211 hlimit = dst_metric(dst, RTAX_HOPLIMIT); 212 if (hlimit < 0) 213 hlimit = ipv6_get_hoplimit(dst->dev); 214 215 tclass = -1; 216 if (np) 217 tclass = np->tclass; 218 if (tclass < 0) 219 tclass = 0; 220 221 *(u32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel; 222 223 hdr->payload_len = htons(seg_len); 224 hdr->nexthdr = proto; 225 hdr->hop_limit = hlimit; 226 227 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 228 ipv6_addr_copy(&hdr->daddr, first_hop); 229 230 skb->priority = sk->sk_priority; 231 232 mtu = dst_mtu(dst); 233 if ((skb->len <= mtu) || ipfragok) { 234 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 235 return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev, 236 dst_output); 237 } 238 239 if (net_ratelimit()) 240 printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n"); 241 skb->dev = dst->dev; 242 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); 243 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 244 kfree_skb(skb); 245 return -EMSGSIZE; 246 } 247 248 /* 249 * To avoid extra problems ND packets are send through this 250 * routine. It's code duplication but I really want to avoid 251 * extra checks since ipv6_build_header is used by TCP (which 252 * is for us performance critical) 253 */ 254 255 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev, 256 struct in6_addr *saddr, struct in6_addr *daddr, 257 int proto, int len) 258 { 259 struct ipv6_pinfo *np = inet6_sk(sk); 260 struct ipv6hdr *hdr; 261 int totlen; 262 263 skb->protocol = htons(ETH_P_IPV6); 264 skb->dev = dev; 265 266 totlen = len + sizeof(struct ipv6hdr); 267 268 hdr = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr)); 269 skb->nh.ipv6h = hdr; 270 271 *(u32*)hdr = htonl(0x60000000); 272 273 hdr->payload_len = htons(len); 274 hdr->nexthdr = proto; 275 hdr->hop_limit = np->hop_limit; 276 277 ipv6_addr_copy(&hdr->saddr, saddr); 278 ipv6_addr_copy(&hdr->daddr, daddr); 279 280 return 0; 281 } 282 283 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 284 { 285 struct ip6_ra_chain *ra; 286 struct sock *last = NULL; 287 288 read_lock(&ip6_ra_lock); 289 for (ra = ip6_ra_chain; ra; ra = ra->next) { 290 struct sock *sk = ra->sk; 291 if (sk && ra->sel == sel && 292 (!sk->sk_bound_dev_if || 293 sk->sk_bound_dev_if == skb->dev->ifindex)) { 294 if (last) { 295 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 296 if (skb2) 297 rawv6_rcv(last, skb2); 298 } 299 last = sk; 300 } 301 } 302 303 if (last) { 304 rawv6_rcv(last, skb); 305 read_unlock(&ip6_ra_lock); 306 return 1; 307 } 308 read_unlock(&ip6_ra_lock); 309 return 0; 310 } 311 312 static inline int ip6_forward_finish(struct sk_buff *skb) 313 { 314 return dst_output(skb); 315 } 316 317 int ip6_forward(struct sk_buff *skb) 318 { 319 struct dst_entry *dst = skb->dst; 320 struct ipv6hdr *hdr = skb->nh.ipv6h; 321 struct inet6_skb_parm *opt = IP6CB(skb); 322 323 if (ipv6_devconf.forwarding == 0) 324 goto error; 325 326 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 327 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS); 328 goto drop; 329 } 330 331 skb->ip_summed = CHECKSUM_NONE; 332 333 /* 334 * We DO NOT make any processing on 335 * RA packets, pushing them to user level AS IS 336 * without ane WARRANTY that application will be able 337 * to interpret them. The reason is that we 338 * cannot make anything clever here. 339 * 340 * We are not end-node, so that if packet contains 341 * AH/ESP, we cannot make anything. 342 * Defragmentation also would be mistake, RA packets 343 * cannot be fragmented, because there is no warranty 344 * that different fragments will go along one path. --ANK 345 */ 346 if (opt->ra) { 347 u8 *ptr = skb->nh.raw + opt->ra; 348 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3])) 349 return 0; 350 } 351 352 /* 353 * check and decrement ttl 354 */ 355 if (hdr->hop_limit <= 1) { 356 /* Force OUTPUT device used as source address */ 357 skb->dev = dst->dev; 358 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 359 0, skb->dev); 360 361 kfree_skb(skb); 362 return -ETIMEDOUT; 363 } 364 365 if (!xfrm6_route_forward(skb)) { 366 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS); 367 goto drop; 368 } 369 dst = skb->dst; 370 371 /* IPv6 specs say nothing about it, but it is clear that we cannot 372 send redirects to source routed frames. 373 */ 374 if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) { 375 struct in6_addr *target = NULL; 376 struct rt6_info *rt; 377 struct neighbour *n = dst->neighbour; 378 379 /* 380 * incoming and outgoing devices are the same 381 * send a redirect. 382 */ 383 384 rt = (struct rt6_info *) dst; 385 if ((rt->rt6i_flags & RTF_GATEWAY)) 386 target = (struct in6_addr*)&n->primary_key; 387 else 388 target = &hdr->daddr; 389 390 /* Limit redirects both by destination (here) 391 and by source (inside ndisc_send_redirect) 392 */ 393 if (xrlim_allow(dst, 1*HZ)) 394 ndisc_send_redirect(skb, n, target); 395 } else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK 396 |IPV6_ADDR_LINKLOCAL)) { 397 /* This check is security critical. */ 398 goto error; 399 } 400 401 if (skb->len > dst_mtu(dst)) { 402 /* Again, force OUTPUT device used as source address */ 403 skb->dev = dst->dev; 404 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev); 405 IP6_INC_STATS_BH(IPSTATS_MIB_INTOOBIGERRORS); 406 IP6_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS); 407 kfree_skb(skb); 408 return -EMSGSIZE; 409 } 410 411 if (skb_cow(skb, dst->dev->hard_header_len)) { 412 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 413 goto drop; 414 } 415 416 hdr = skb->nh.ipv6h; 417 418 /* Mangling hops number delayed to point after skb COW */ 419 420 hdr->hop_limit--; 421 422 IP6_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS); 423 return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish); 424 425 error: 426 IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS); 427 drop: 428 kfree_skb(skb); 429 return -EINVAL; 430 } 431 432 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 433 { 434 to->pkt_type = from->pkt_type; 435 to->priority = from->priority; 436 to->protocol = from->protocol; 437 dst_release(to->dst); 438 to->dst = dst_clone(from->dst); 439 to->dev = from->dev; 440 441 #ifdef CONFIG_NET_SCHED 442 to->tc_index = from->tc_index; 443 #endif 444 #ifdef CONFIG_NETFILTER 445 to->nfmark = from->nfmark; 446 /* Connection association is same as pre-frag packet */ 447 nf_conntrack_put(to->nfct); 448 to->nfct = from->nfct; 449 nf_conntrack_get(to->nfct); 450 to->nfctinfo = from->nfctinfo; 451 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 452 nf_conntrack_put_reasm(to->nfct_reasm); 453 to->nfct_reasm = from->nfct_reasm; 454 nf_conntrack_get_reasm(to->nfct_reasm); 455 #endif 456 #ifdef CONFIG_BRIDGE_NETFILTER 457 nf_bridge_put(to->nf_bridge); 458 to->nf_bridge = from->nf_bridge; 459 nf_bridge_get(to->nf_bridge); 460 #endif 461 #endif 462 skb_copy_secmark(to, from); 463 } 464 465 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 466 { 467 u16 offset = sizeof(struct ipv6hdr); 468 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); 469 unsigned int packet_len = skb->tail - skb->nh.raw; 470 int found_rhdr = 0; 471 *nexthdr = &skb->nh.ipv6h->nexthdr; 472 473 while (offset + 1 <= packet_len) { 474 475 switch (**nexthdr) { 476 477 case NEXTHDR_HOP: 478 case NEXTHDR_ROUTING: 479 case NEXTHDR_DEST: 480 if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1; 481 if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset; 482 offset += ipv6_optlen(exthdr); 483 *nexthdr = &exthdr->nexthdr; 484 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); 485 break; 486 default : 487 return offset; 488 } 489 } 490 491 return offset; 492 } 493 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt); 494 495 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 496 { 497 struct net_device *dev; 498 struct sk_buff *frag; 499 struct rt6_info *rt = (struct rt6_info*)skb->dst; 500 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 501 struct ipv6hdr *tmp_hdr; 502 struct frag_hdr *fh; 503 unsigned int mtu, hlen, left, len; 504 u32 frag_id = 0; 505 int ptr, offset = 0, err=0; 506 u8 *prevhdr, nexthdr = 0; 507 508 dev = rt->u.dst.dev; 509 hlen = ip6_find_1stfragopt(skb, &prevhdr); 510 nexthdr = *prevhdr; 511 512 mtu = dst_mtu(&rt->u.dst); 513 if (np && np->frag_size < mtu) { 514 if (np->frag_size) 515 mtu = np->frag_size; 516 } 517 mtu -= hlen + sizeof(struct frag_hdr); 518 519 if (skb_shinfo(skb)->frag_list) { 520 int first_len = skb_pagelen(skb); 521 522 if (first_len - hlen > mtu || 523 ((first_len - hlen) & 7) || 524 skb_cloned(skb)) 525 goto slow_path; 526 527 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 528 /* Correct geometry. */ 529 if (frag->len > mtu || 530 ((frag->len & 7) && frag->next) || 531 skb_headroom(frag) < hlen) 532 goto slow_path; 533 534 /* Partially cloned skb? */ 535 if (skb_shared(frag)) 536 goto slow_path; 537 538 BUG_ON(frag->sk); 539 if (skb->sk) { 540 sock_hold(skb->sk); 541 frag->sk = skb->sk; 542 frag->destructor = sock_wfree; 543 skb->truesize -= frag->truesize; 544 } 545 } 546 547 err = 0; 548 offset = 0; 549 frag = skb_shinfo(skb)->frag_list; 550 skb_shinfo(skb)->frag_list = NULL; 551 /* BUILD HEADER */ 552 553 tmp_hdr = kmalloc(hlen, GFP_ATOMIC); 554 if (!tmp_hdr) { 555 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 556 return -ENOMEM; 557 } 558 559 *prevhdr = NEXTHDR_FRAGMENT; 560 memcpy(tmp_hdr, skb->nh.raw, hlen); 561 __skb_pull(skb, hlen); 562 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 563 skb->nh.raw = __skb_push(skb, hlen); 564 memcpy(skb->nh.raw, tmp_hdr, hlen); 565 566 ipv6_select_ident(skb, fh); 567 fh->nexthdr = nexthdr; 568 fh->reserved = 0; 569 fh->frag_off = htons(IP6_MF); 570 frag_id = fh->identification; 571 572 first_len = skb_pagelen(skb); 573 skb->data_len = first_len - skb_headlen(skb); 574 skb->len = first_len; 575 skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr)); 576 577 578 for (;;) { 579 /* Prepare header of the next frame, 580 * before previous one went down. */ 581 if (frag) { 582 frag->ip_summed = CHECKSUM_NONE; 583 frag->h.raw = frag->data; 584 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 585 frag->nh.raw = __skb_push(frag, hlen); 586 memcpy(frag->nh.raw, tmp_hdr, hlen); 587 offset += skb->len - hlen - sizeof(struct frag_hdr); 588 fh->nexthdr = nexthdr; 589 fh->reserved = 0; 590 fh->frag_off = htons(offset); 591 if (frag->next != NULL) 592 fh->frag_off |= htons(IP6_MF); 593 fh->identification = frag_id; 594 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 595 ip6_copy_metadata(frag, skb); 596 } 597 598 err = output(skb); 599 if (err || !frag) 600 break; 601 602 skb = frag; 603 frag = skb->next; 604 skb->next = NULL; 605 } 606 607 kfree(tmp_hdr); 608 609 if (err == 0) { 610 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 611 return 0; 612 } 613 614 while (frag) { 615 skb = frag->next; 616 kfree_skb(frag); 617 frag = skb; 618 } 619 620 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 621 return err; 622 } 623 624 slow_path: 625 left = skb->len - hlen; /* Space per frame */ 626 ptr = hlen; /* Where to start from */ 627 628 /* 629 * Fragment the datagram. 630 */ 631 632 *prevhdr = NEXTHDR_FRAGMENT; 633 634 /* 635 * Keep copying data until we run out. 636 */ 637 while(left > 0) { 638 len = left; 639 /* IF: it doesn't fit, use 'mtu' - the data space left */ 640 if (len > mtu) 641 len = mtu; 642 /* IF: we are not sending upto and including the packet end 643 then align the next start on an eight byte boundary */ 644 if (len < left) { 645 len &= ~7; 646 } 647 /* 648 * Allocate buffer. 649 */ 650 651 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { 652 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 653 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 654 err = -ENOMEM; 655 goto fail; 656 } 657 658 /* 659 * Set up data on packet 660 */ 661 662 ip6_copy_metadata(frag, skb); 663 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev)); 664 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 665 frag->nh.raw = frag->data; 666 fh = (struct frag_hdr*)(frag->data + hlen); 667 frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr); 668 669 /* 670 * Charge the memory for the fragment to any owner 671 * it might possess 672 */ 673 if (skb->sk) 674 skb_set_owner_w(frag, skb->sk); 675 676 /* 677 * Copy the packet header into the new buffer. 678 */ 679 memcpy(frag->nh.raw, skb->data, hlen); 680 681 /* 682 * Build fragment header. 683 */ 684 fh->nexthdr = nexthdr; 685 fh->reserved = 0; 686 if (!frag_id) { 687 ipv6_select_ident(skb, fh); 688 frag_id = fh->identification; 689 } else 690 fh->identification = frag_id; 691 692 /* 693 * Copy a block of the IP datagram. 694 */ 695 if (skb_copy_bits(skb, ptr, frag->h.raw, len)) 696 BUG(); 697 left -= len; 698 699 fh->frag_off = htons(offset); 700 if (left > 0) 701 fh->frag_off |= htons(IP6_MF); 702 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 703 704 ptr += len; 705 offset += len; 706 707 /* 708 * Put this fragment into the sending queue. 709 */ 710 711 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES); 712 713 err = output(frag); 714 if (err) 715 goto fail; 716 } 717 kfree_skb(skb); 718 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 719 return err; 720 721 fail: 722 kfree_skb(skb); 723 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 724 return err; 725 } 726 727 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) 728 { 729 int err = 0; 730 731 *dst = NULL; 732 if (sk) { 733 struct ipv6_pinfo *np = inet6_sk(sk); 734 735 *dst = sk_dst_check(sk, np->dst_cookie); 736 if (*dst) { 737 struct rt6_info *rt = (struct rt6_info*)*dst; 738 739 /* Yes, checking route validity in not connected 740 * case is not very simple. Take into account, 741 * that we do not support routing by source, TOS, 742 * and MSG_DONTROUTE --ANK (980726) 743 * 744 * 1. If route was host route, check that 745 * cached destination is current. 746 * If it is network route, we still may 747 * check its validity using saved pointer 748 * to the last used address: daddr_cache. 749 * We do not want to save whole address now, 750 * (because main consumer of this service 751 * is tcp, which has not this problem), 752 * so that the last trick works only on connected 753 * sockets. 754 * 2. oif also should be the same. 755 */ 756 if (((rt->rt6i_dst.plen != 128 || 757 !ipv6_addr_equal(&fl->fl6_dst, 758 &rt->rt6i_dst.addr)) 759 && (np->daddr_cache == NULL || 760 !ipv6_addr_equal(&fl->fl6_dst, 761 np->daddr_cache))) 762 || (fl->oif && fl->oif != (*dst)->dev->ifindex)) { 763 dst_release(*dst); 764 *dst = NULL; 765 } 766 } 767 } 768 769 if (*dst == NULL) 770 *dst = ip6_route_output(sk, fl); 771 772 if ((err = (*dst)->error)) 773 goto out_err_release; 774 775 if (ipv6_addr_any(&fl->fl6_src)) { 776 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src); 777 778 if (err) 779 goto out_err_release; 780 } 781 782 return 0; 783 784 out_err_release: 785 dst_release(*dst); 786 *dst = NULL; 787 return err; 788 } 789 790 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 791 792 static inline int ip6_ufo_append_data(struct sock *sk, 793 int getfrag(void *from, char *to, int offset, int len, 794 int odd, struct sk_buff *skb), 795 void *from, int length, int hh_len, int fragheaderlen, 796 int transhdrlen, int mtu,unsigned int flags) 797 798 { 799 struct sk_buff *skb; 800 int err; 801 802 /* There is support for UDP large send offload by network 803 * device, so create one single skb packet containing complete 804 * udp datagram 805 */ 806 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 807 skb = sock_alloc_send_skb(sk, 808 hh_len + fragheaderlen + transhdrlen + 20, 809 (flags & MSG_DONTWAIT), &err); 810 if (skb == NULL) 811 return -ENOMEM; 812 813 /* reserve space for Hardware header */ 814 skb_reserve(skb, hh_len); 815 816 /* create space for UDP/IP header */ 817 skb_put(skb,fragheaderlen + transhdrlen); 818 819 /* initialize network header pointer */ 820 skb->nh.raw = skb->data; 821 822 /* initialize protocol header pointer */ 823 skb->h.raw = skb->data + fragheaderlen; 824 825 skb->ip_summed = CHECKSUM_HW; 826 skb->csum = 0; 827 sk->sk_sndmsg_off = 0; 828 } 829 830 err = skb_append_datato_frags(sk,skb, getfrag, from, 831 (length - transhdrlen)); 832 if (!err) { 833 struct frag_hdr fhdr; 834 835 /* specify the length of each IP datagram fragment*/ 836 skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 837 sizeof(struct frag_hdr); 838 skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4; 839 ipv6_select_ident(skb, &fhdr); 840 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 841 __skb_queue_tail(&sk->sk_write_queue, skb); 842 843 return 0; 844 } 845 /* There is not enough support do UPD LSO, 846 * so follow normal path 847 */ 848 kfree_skb(skb); 849 850 return err; 851 } 852 853 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 854 int offset, int len, int odd, struct sk_buff *skb), 855 void *from, int length, int transhdrlen, 856 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl, 857 struct rt6_info *rt, unsigned int flags) 858 { 859 struct inet_sock *inet = inet_sk(sk); 860 struct ipv6_pinfo *np = inet6_sk(sk); 861 struct sk_buff *skb; 862 unsigned int maxfraglen, fragheaderlen; 863 int exthdrlen; 864 int hh_len; 865 int mtu; 866 int copy; 867 int err; 868 int offset = 0; 869 int csummode = CHECKSUM_NONE; 870 871 if (flags&MSG_PROBE) 872 return 0; 873 if (skb_queue_empty(&sk->sk_write_queue)) { 874 /* 875 * setup for corking 876 */ 877 if (opt) { 878 if (np->cork.opt == NULL) { 879 np->cork.opt = kmalloc(opt->tot_len, 880 sk->sk_allocation); 881 if (unlikely(np->cork.opt == NULL)) 882 return -ENOBUFS; 883 } else if (np->cork.opt->tot_len < opt->tot_len) { 884 printk(KERN_DEBUG "ip6_append_data: invalid option length\n"); 885 return -EINVAL; 886 } 887 memcpy(np->cork.opt, opt, opt->tot_len); 888 inet->cork.flags |= IPCORK_OPT; 889 /* need source address above miyazawa*/ 890 } 891 dst_hold(&rt->u.dst); 892 np->cork.rt = rt; 893 inet->cork.fl = *fl; 894 np->cork.hop_limit = hlimit; 895 np->cork.tclass = tclass; 896 mtu = dst_mtu(rt->u.dst.path); 897 if (np->frag_size < mtu) { 898 if (np->frag_size) 899 mtu = np->frag_size; 900 } 901 inet->cork.fragsize = mtu; 902 if (dst_allfrag(rt->u.dst.path)) 903 inet->cork.flags |= IPCORK_ALLFRAG; 904 inet->cork.length = 0; 905 sk->sk_sndmsg_page = NULL; 906 sk->sk_sndmsg_off = 0; 907 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0); 908 length += exthdrlen; 909 transhdrlen += exthdrlen; 910 } else { 911 rt = np->cork.rt; 912 fl = &inet->cork.fl; 913 if (inet->cork.flags & IPCORK_OPT) 914 opt = np->cork.opt; 915 transhdrlen = 0; 916 exthdrlen = 0; 917 mtu = inet->cork.fragsize; 918 } 919 920 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 921 922 fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0); 923 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); 924 925 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 926 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { 927 ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen); 928 return -EMSGSIZE; 929 } 930 } 931 932 /* 933 * Let's try using as much space as possible. 934 * Use MTU if total length of the message fits into the MTU. 935 * Otherwise, we need to reserve fragment header and 936 * fragment alignment (= 8-15 octects, in total). 937 * 938 * Note that we may need to "move" the data from the tail of 939 * of the buffer to the new fragment when we split 940 * the message. 941 * 942 * FIXME: It may be fragmented into multiple chunks 943 * at once if non-fragmentable extension headers 944 * are too large. 945 * --yoshfuji 946 */ 947 948 inet->cork.length += length; 949 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 950 (rt->u.dst.dev->features & NETIF_F_UFO)) { 951 952 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, 953 fragheaderlen, transhdrlen, mtu, 954 flags); 955 if (err) 956 goto error; 957 return 0; 958 } 959 960 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 961 goto alloc_new_skb; 962 963 while (length > 0) { 964 /* Check if the remaining data fits into current packet. */ 965 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 966 if (copy < length) 967 copy = maxfraglen - skb->len; 968 969 if (copy <= 0) { 970 char *data; 971 unsigned int datalen; 972 unsigned int fraglen; 973 unsigned int fraggap; 974 unsigned int alloclen; 975 struct sk_buff *skb_prev; 976 alloc_new_skb: 977 skb_prev = skb; 978 979 /* There's no room in the current skb */ 980 if (skb_prev) 981 fraggap = skb_prev->len - maxfraglen; 982 else 983 fraggap = 0; 984 985 /* 986 * If remaining data exceeds the mtu, 987 * we know we need more fragment(s). 988 */ 989 datalen = length + fraggap; 990 if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 991 datalen = maxfraglen - fragheaderlen; 992 993 fraglen = datalen + fragheaderlen; 994 if ((flags & MSG_MORE) && 995 !(rt->u.dst.dev->features&NETIF_F_SG)) 996 alloclen = mtu; 997 else 998 alloclen = datalen + fragheaderlen; 999 1000 /* 1001 * The last fragment gets additional space at tail. 1002 * Note: we overallocate on fragments with MSG_MODE 1003 * because we have no idea if we're the last one. 1004 */ 1005 if (datalen == length + fraggap) 1006 alloclen += rt->u.dst.trailer_len; 1007 1008 /* 1009 * We just reserve space for fragment header. 1010 * Note: this may be overallocation if the message 1011 * (without MSG_MORE) fits into the MTU. 1012 */ 1013 alloclen += sizeof(struct frag_hdr); 1014 1015 if (transhdrlen) { 1016 skb = sock_alloc_send_skb(sk, 1017 alloclen + hh_len, 1018 (flags & MSG_DONTWAIT), &err); 1019 } else { 1020 skb = NULL; 1021 if (atomic_read(&sk->sk_wmem_alloc) <= 1022 2 * sk->sk_sndbuf) 1023 skb = sock_wmalloc(sk, 1024 alloclen + hh_len, 1, 1025 sk->sk_allocation); 1026 if (unlikely(skb == NULL)) 1027 err = -ENOBUFS; 1028 } 1029 if (skb == NULL) 1030 goto error; 1031 /* 1032 * Fill in the control structures 1033 */ 1034 skb->ip_summed = csummode; 1035 skb->csum = 0; 1036 /* reserve for fragmentation */ 1037 skb_reserve(skb, hh_len+sizeof(struct frag_hdr)); 1038 1039 /* 1040 * Find where to start putting bytes 1041 */ 1042 data = skb_put(skb, fraglen); 1043 skb->nh.raw = data + exthdrlen; 1044 data += fragheaderlen; 1045 skb->h.raw = data + exthdrlen; 1046 1047 if (fraggap) { 1048 skb->csum = skb_copy_and_csum_bits( 1049 skb_prev, maxfraglen, 1050 data + transhdrlen, fraggap, 0); 1051 skb_prev->csum = csum_sub(skb_prev->csum, 1052 skb->csum); 1053 data += fraggap; 1054 skb_trim(skb_prev, maxfraglen); 1055 } 1056 copy = datalen - transhdrlen - fraggap; 1057 if (copy < 0) { 1058 err = -EINVAL; 1059 kfree_skb(skb); 1060 goto error; 1061 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1062 err = -EFAULT; 1063 kfree_skb(skb); 1064 goto error; 1065 } 1066 1067 offset += copy; 1068 length -= datalen - fraggap; 1069 transhdrlen = 0; 1070 exthdrlen = 0; 1071 csummode = CHECKSUM_NONE; 1072 1073 /* 1074 * Put the packet on the pending queue 1075 */ 1076 __skb_queue_tail(&sk->sk_write_queue, skb); 1077 continue; 1078 } 1079 1080 if (copy > length) 1081 copy = length; 1082 1083 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 1084 unsigned int off; 1085 1086 off = skb->len; 1087 if (getfrag(from, skb_put(skb, copy), 1088 offset, copy, off, skb) < 0) { 1089 __skb_trim(skb, off); 1090 err = -EFAULT; 1091 goto error; 1092 } 1093 } else { 1094 int i = skb_shinfo(skb)->nr_frags; 1095 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1096 struct page *page = sk->sk_sndmsg_page; 1097 int off = sk->sk_sndmsg_off; 1098 unsigned int left; 1099 1100 if (page && (left = PAGE_SIZE - off) > 0) { 1101 if (copy >= left) 1102 copy = left; 1103 if (page != frag->page) { 1104 if (i == MAX_SKB_FRAGS) { 1105 err = -EMSGSIZE; 1106 goto error; 1107 } 1108 get_page(page); 1109 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1110 frag = &skb_shinfo(skb)->frags[i]; 1111 } 1112 } else if(i < MAX_SKB_FRAGS) { 1113 if (copy > PAGE_SIZE) 1114 copy = PAGE_SIZE; 1115 page = alloc_pages(sk->sk_allocation, 0); 1116 if (page == NULL) { 1117 err = -ENOMEM; 1118 goto error; 1119 } 1120 sk->sk_sndmsg_page = page; 1121 sk->sk_sndmsg_off = 0; 1122 1123 skb_fill_page_desc(skb, i, page, 0, 0); 1124 frag = &skb_shinfo(skb)->frags[i]; 1125 skb->truesize += PAGE_SIZE; 1126 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1127 } else { 1128 err = -EMSGSIZE; 1129 goto error; 1130 } 1131 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1132 err = -EFAULT; 1133 goto error; 1134 } 1135 sk->sk_sndmsg_off += copy; 1136 frag->size += copy; 1137 skb->len += copy; 1138 skb->data_len += copy; 1139 } 1140 offset += copy; 1141 length -= copy; 1142 } 1143 return 0; 1144 error: 1145 inet->cork.length -= length; 1146 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1147 return err; 1148 } 1149 1150 int ip6_push_pending_frames(struct sock *sk) 1151 { 1152 struct sk_buff *skb, *tmp_skb; 1153 struct sk_buff **tail_skb; 1154 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1155 struct inet_sock *inet = inet_sk(sk); 1156 struct ipv6_pinfo *np = inet6_sk(sk); 1157 struct ipv6hdr *hdr; 1158 struct ipv6_txoptions *opt = np->cork.opt; 1159 struct rt6_info *rt = np->cork.rt; 1160 struct flowi *fl = &inet->cork.fl; 1161 unsigned char proto = fl->proto; 1162 int err = 0; 1163 1164 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1165 goto out; 1166 tail_skb = &(skb_shinfo(skb)->frag_list); 1167 1168 /* move skb->data to ip header from ext header */ 1169 if (skb->data < skb->nh.raw) 1170 __skb_pull(skb, skb->nh.raw - skb->data); 1171 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1172 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1173 *tail_skb = tmp_skb; 1174 tail_skb = &(tmp_skb->next); 1175 skb->len += tmp_skb->len; 1176 skb->data_len += tmp_skb->len; 1177 skb->truesize += tmp_skb->truesize; 1178 __sock_put(tmp_skb->sk); 1179 tmp_skb->destructor = NULL; 1180 tmp_skb->sk = NULL; 1181 } 1182 1183 ipv6_addr_copy(final_dst, &fl->fl6_dst); 1184 __skb_pull(skb, skb->h.raw - skb->nh.raw); 1185 if (opt && opt->opt_flen) 1186 ipv6_push_frag_opts(skb, opt, &proto); 1187 if (opt && opt->opt_nflen) 1188 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1189 1190 skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr)); 1191 1192 *(u32*)hdr = fl->fl6_flowlabel | 1193 htonl(0x60000000 | ((int)np->cork.tclass << 20)); 1194 1195 if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) 1196 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 1197 else 1198 hdr->payload_len = 0; 1199 hdr->hop_limit = np->cork.hop_limit; 1200 hdr->nexthdr = proto; 1201 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 1202 ipv6_addr_copy(&hdr->daddr, final_dst); 1203 1204 skb->priority = sk->sk_priority; 1205 1206 skb->dst = dst_clone(&rt->u.dst); 1207 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 1208 err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output); 1209 if (err) { 1210 if (err > 0) 1211 err = np->recverr ? net_xmit_errno(err) : 0; 1212 if (err) 1213 goto error; 1214 } 1215 1216 out: 1217 inet->cork.flags &= ~IPCORK_OPT; 1218 kfree(np->cork.opt); 1219 np->cork.opt = NULL; 1220 if (np->cork.rt) { 1221 dst_release(&np->cork.rt->u.dst); 1222 np->cork.rt = NULL; 1223 inet->cork.flags &= ~IPCORK_ALLFRAG; 1224 } 1225 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1226 return err; 1227 error: 1228 goto out; 1229 } 1230 1231 void ip6_flush_pending_frames(struct sock *sk) 1232 { 1233 struct inet_sock *inet = inet_sk(sk); 1234 struct ipv6_pinfo *np = inet6_sk(sk); 1235 struct sk_buff *skb; 1236 1237 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1238 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1239 kfree_skb(skb); 1240 } 1241 1242 inet->cork.flags &= ~IPCORK_OPT; 1243 1244 kfree(np->cork.opt); 1245 np->cork.opt = NULL; 1246 if (np->cork.rt) { 1247 dst_release(&np->cork.rt->u.dst); 1248 np->cork.rt = NULL; 1249 inet->cork.flags &= ~IPCORK_ALLFRAG; 1250 } 1251 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1252 } 1253