1 /* 2 * IPv6 output functions 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * Based on linux/net/ipv4/ip_output.c 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 * 15 * Changes: 16 * A.N.Kuznetsov : airthmetics in fragmentation. 17 * extension headers are implemented. 18 * route changes now work. 19 * ip6_forward does not confuse sniffers. 20 * etc. 21 * 22 * H. von Brand : Added missing #include <linux/string.h> 23 * Imran Patel : frag id should be in NBO 24 * Kazunori MIYAZAWA @USAGI 25 * : add ip6_append_data and related functions 26 * for datagram xmit 27 */ 28 29 #include <linux/errno.h> 30 #include <linux/kernel.h> 31 #include <linux/string.h> 32 #include <linux/socket.h> 33 #include <linux/net.h> 34 #include <linux/netdevice.h> 35 #include <linux/if_arp.h> 36 #include <linux/in6.h> 37 #include <linux/tcp.h> 38 #include <linux/route.h> 39 #include <linux/module.h> 40 #include <linux/slab.h> 41 42 #include <linux/netfilter.h> 43 #include <linux/netfilter_ipv6.h> 44 45 #include <net/sock.h> 46 #include <net/snmp.h> 47 48 #include <net/ipv6.h> 49 #include <net/ndisc.h> 50 #include <net/protocol.h> 51 #include <net/ip6_route.h> 52 #include <net/addrconf.h> 53 #include <net/rawv6.h> 54 #include <net/icmp.h> 55 #include <net/xfrm.h> 56 #include <net/checksum.h> 57 #include <linux/mroute6.h> 58 59 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)); 60 61 int __ip6_local_out(struct sk_buff *skb) 62 { 63 int len; 64 65 len = skb->len - sizeof(struct ipv6hdr); 66 if (len > IPV6_MAXPLEN) 67 len = 0; 68 ipv6_hdr(skb)->payload_len = htons(len); 69 70 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 71 skb_dst(skb)->dev, dst_output); 72 } 73 74 int ip6_local_out(struct sk_buff *skb) 75 { 76 int err; 77 78 err = __ip6_local_out(skb); 79 if (likely(err == 1)) 80 err = dst_output(skb); 81 82 return err; 83 } 84 EXPORT_SYMBOL_GPL(ip6_local_out); 85 86 /* dev_loopback_xmit for use with netfilter. */ 87 static int ip6_dev_loopback_xmit(struct sk_buff *newskb) 88 { 89 skb_reset_mac_header(newskb); 90 __skb_pull(newskb, skb_network_offset(newskb)); 91 newskb->pkt_type = PACKET_LOOPBACK; 92 newskb->ip_summed = CHECKSUM_UNNECESSARY; 93 WARN_ON(!skb_dst(newskb)); 94 95 netif_rx_ni(newskb); 96 return 0; 97 } 98 99 static int ip6_finish_output2(struct sk_buff *skb) 100 { 101 struct dst_entry *dst = skb_dst(skb); 102 struct net_device *dev = dst->dev; 103 struct neighbour *neigh; 104 105 skb->protocol = htons(ETH_P_IPV6); 106 skb->dev = dev; 107 108 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { 109 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 110 111 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) && 112 ((mroute6_socket(dev_net(dev), skb) && 113 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 114 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, 115 &ipv6_hdr(skb)->saddr))) { 116 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 117 118 /* Do not check for IFF_ALLMULTI; multicast routing 119 is not supported in any case. 120 */ 121 if (newskb) 122 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 123 newskb, NULL, newskb->dev, 124 ip6_dev_loopback_xmit); 125 126 if (ipv6_hdr(skb)->hop_limit == 0) { 127 IP6_INC_STATS(dev_net(dev), idev, 128 IPSTATS_MIB_OUTDISCARDS); 129 kfree_skb(skb); 130 return 0; 131 } 132 } 133 134 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST, 135 skb->len); 136 } 137 138 rcu_read_lock(); 139 neigh = dst_get_neighbour_noref(dst); 140 if (neigh) { 141 int res = neigh_output(neigh, skb); 142 143 rcu_read_unlock(); 144 return res; 145 } 146 rcu_read_unlock(); 147 IP6_INC_STATS_BH(dev_net(dst->dev), 148 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 149 kfree_skb(skb); 150 return -EINVAL; 151 } 152 153 static int ip6_finish_output(struct sk_buff *skb) 154 { 155 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || 156 dst_allfrag(skb_dst(skb))) 157 return ip6_fragment(skb, ip6_finish_output2); 158 else 159 return ip6_finish_output2(skb); 160 } 161 162 int ip6_output(struct sk_buff *skb) 163 { 164 struct net_device *dev = skb_dst(skb)->dev; 165 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 166 if (unlikely(idev->cnf.disable_ipv6)) { 167 IP6_INC_STATS(dev_net(dev), idev, 168 IPSTATS_MIB_OUTDISCARDS); 169 kfree_skb(skb); 170 return 0; 171 } 172 173 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev, 174 ip6_finish_output, 175 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 176 } 177 178 /* 179 * xmit an sk_buff (used by TCP, SCTP and DCCP) 180 */ 181 182 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 183 struct ipv6_txoptions *opt, int tclass) 184 { 185 struct net *net = sock_net(sk); 186 struct ipv6_pinfo *np = inet6_sk(sk); 187 struct in6_addr *first_hop = &fl6->daddr; 188 struct dst_entry *dst = skb_dst(skb); 189 struct ipv6hdr *hdr; 190 u8 proto = fl6->flowi6_proto; 191 int seg_len = skb->len; 192 int hlimit = -1; 193 u32 mtu; 194 195 if (opt) { 196 unsigned int head_room; 197 198 /* First: exthdrs may take lots of space (~8K for now) 199 MAX_HEADER is not enough. 200 */ 201 head_room = opt->opt_nflen + opt->opt_flen; 202 seg_len += head_room; 203 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 204 205 if (skb_headroom(skb) < head_room) { 206 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 207 if (skb2 == NULL) { 208 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 209 IPSTATS_MIB_OUTDISCARDS); 210 kfree_skb(skb); 211 return -ENOBUFS; 212 } 213 consume_skb(skb); 214 skb = skb2; 215 skb_set_owner_w(skb, sk); 216 } 217 if (opt->opt_flen) 218 ipv6_push_frag_opts(skb, opt, &proto); 219 if (opt->opt_nflen) 220 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 221 } 222 223 skb_push(skb, sizeof(struct ipv6hdr)); 224 skb_reset_network_header(skb); 225 hdr = ipv6_hdr(skb); 226 227 /* 228 * Fill in the IPv6 header 229 */ 230 if (np) 231 hlimit = np->hop_limit; 232 if (hlimit < 0) 233 hlimit = ip6_dst_hoplimit(dst); 234 235 *(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl6->flowlabel; 236 237 hdr->payload_len = htons(seg_len); 238 hdr->nexthdr = proto; 239 hdr->hop_limit = hlimit; 240 241 hdr->saddr = fl6->saddr; 242 hdr->daddr = *first_hop; 243 244 skb->priority = sk->sk_priority; 245 skb->mark = sk->sk_mark; 246 247 mtu = dst_mtu(dst); 248 if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) { 249 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 250 IPSTATS_MIB_OUT, skb->len); 251 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 252 dst->dev, dst_output); 253 } 254 255 net_dbg_ratelimited("IPv6: sending pkt_too_big to self\n"); 256 skb->dev = dst->dev; 257 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 258 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 259 kfree_skb(skb); 260 return -EMSGSIZE; 261 } 262 263 EXPORT_SYMBOL(ip6_xmit); 264 265 /* 266 * To avoid extra problems ND packets are send through this 267 * routine. It's code duplication but I really want to avoid 268 * extra checks since ipv6_build_header is used by TCP (which 269 * is for us performance critical) 270 */ 271 272 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev, 273 const struct in6_addr *saddr, const struct in6_addr *daddr, 274 int proto, int len) 275 { 276 struct ipv6_pinfo *np = inet6_sk(sk); 277 struct ipv6hdr *hdr; 278 279 skb->protocol = htons(ETH_P_IPV6); 280 skb->dev = dev; 281 282 skb_reset_network_header(skb); 283 skb_put(skb, sizeof(struct ipv6hdr)); 284 hdr = ipv6_hdr(skb); 285 286 *(__be32*)hdr = htonl(0x60000000); 287 288 hdr->payload_len = htons(len); 289 hdr->nexthdr = proto; 290 hdr->hop_limit = np->hop_limit; 291 292 hdr->saddr = *saddr; 293 hdr->daddr = *daddr; 294 295 return 0; 296 } 297 298 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 299 { 300 struct ip6_ra_chain *ra; 301 struct sock *last = NULL; 302 303 read_lock(&ip6_ra_lock); 304 for (ra = ip6_ra_chain; ra; ra = ra->next) { 305 struct sock *sk = ra->sk; 306 if (sk && ra->sel == sel && 307 (!sk->sk_bound_dev_if || 308 sk->sk_bound_dev_if == skb->dev->ifindex)) { 309 if (last) { 310 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 311 if (skb2) 312 rawv6_rcv(last, skb2); 313 } 314 last = sk; 315 } 316 } 317 318 if (last) { 319 rawv6_rcv(last, skb); 320 read_unlock(&ip6_ra_lock); 321 return 1; 322 } 323 read_unlock(&ip6_ra_lock); 324 return 0; 325 } 326 327 static int ip6_forward_proxy_check(struct sk_buff *skb) 328 { 329 struct ipv6hdr *hdr = ipv6_hdr(skb); 330 u8 nexthdr = hdr->nexthdr; 331 __be16 frag_off; 332 int offset; 333 334 if (ipv6_ext_hdr(nexthdr)) { 335 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 336 if (offset < 0) 337 return 0; 338 } else 339 offset = sizeof(struct ipv6hdr); 340 341 if (nexthdr == IPPROTO_ICMPV6) { 342 struct icmp6hdr *icmp6; 343 344 if (!pskb_may_pull(skb, (skb_network_header(skb) + 345 offset + 1 - skb->data))) 346 return 0; 347 348 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 349 350 switch (icmp6->icmp6_type) { 351 case NDISC_ROUTER_SOLICITATION: 352 case NDISC_ROUTER_ADVERTISEMENT: 353 case NDISC_NEIGHBOUR_SOLICITATION: 354 case NDISC_NEIGHBOUR_ADVERTISEMENT: 355 case NDISC_REDIRECT: 356 /* For reaction involving unicast neighbor discovery 357 * message destined to the proxied address, pass it to 358 * input function. 359 */ 360 return 1; 361 default: 362 break; 363 } 364 } 365 366 /* 367 * The proxying router can't forward traffic sent to a link-local 368 * address, so signal the sender and discard the packet. This 369 * behavior is clarified by the MIPv6 specification. 370 */ 371 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 372 dst_link_failure(skb); 373 return -1; 374 } 375 376 return 0; 377 } 378 379 static inline int ip6_forward_finish(struct sk_buff *skb) 380 { 381 return dst_output(skb); 382 } 383 384 int ip6_forward(struct sk_buff *skb) 385 { 386 struct dst_entry *dst = skb_dst(skb); 387 struct ipv6hdr *hdr = ipv6_hdr(skb); 388 struct inet6_skb_parm *opt = IP6CB(skb); 389 struct net *net = dev_net(dst->dev); 390 u32 mtu; 391 392 if (net->ipv6.devconf_all->forwarding == 0) 393 goto error; 394 395 if (skb_warn_if_lro(skb)) 396 goto drop; 397 398 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 399 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS); 400 goto drop; 401 } 402 403 if (skb->pkt_type != PACKET_HOST) 404 goto drop; 405 406 skb_forward_csum(skb); 407 408 /* 409 * We DO NOT make any processing on 410 * RA packets, pushing them to user level AS IS 411 * without ane WARRANTY that application will be able 412 * to interpret them. The reason is that we 413 * cannot make anything clever here. 414 * 415 * We are not end-node, so that if packet contains 416 * AH/ESP, we cannot make anything. 417 * Defragmentation also would be mistake, RA packets 418 * cannot be fragmented, because there is no warranty 419 * that different fragments will go along one path. --ANK 420 */ 421 if (opt->ra) { 422 u8 *ptr = skb_network_header(skb) + opt->ra; 423 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3])) 424 return 0; 425 } 426 427 /* 428 * check and decrement ttl 429 */ 430 if (hdr->hop_limit <= 1) { 431 /* Force OUTPUT device used as source address */ 432 skb->dev = dst->dev; 433 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 434 IP6_INC_STATS_BH(net, 435 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); 436 437 kfree_skb(skb); 438 return -ETIMEDOUT; 439 } 440 441 /* XXX: idev->cnf.proxy_ndp? */ 442 if (net->ipv6.devconf_all->proxy_ndp && 443 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 444 int proxied = ip6_forward_proxy_check(skb); 445 if (proxied > 0) 446 return ip6_input(skb); 447 else if (proxied < 0) { 448 IP6_INC_STATS(net, ip6_dst_idev(dst), 449 IPSTATS_MIB_INDISCARDS); 450 goto drop; 451 } 452 } 453 454 if (!xfrm6_route_forward(skb)) { 455 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS); 456 goto drop; 457 } 458 dst = skb_dst(skb); 459 460 /* IPv6 specs say nothing about it, but it is clear that we cannot 461 send redirects to source routed frames. 462 We don't send redirects to frames decapsulated from IPsec. 463 */ 464 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) { 465 struct in6_addr *target = NULL; 466 struct rt6_info *rt; 467 468 /* 469 * incoming and outgoing devices are the same 470 * send a redirect. 471 */ 472 473 rt = (struct rt6_info *) dst; 474 if (rt->rt6i_flags & RTF_GATEWAY) 475 target = &rt->rt6i_gateway; 476 else 477 target = &hdr->daddr; 478 479 if (!rt->rt6i_peer) 480 rt6_bind_peer(rt, 1); 481 482 /* Limit redirects both by destination (here) 483 and by source (inside ndisc_send_redirect) 484 */ 485 if (inet_peer_xrlim_allow(rt->rt6i_peer, 1*HZ)) 486 ndisc_send_redirect(skb, target); 487 } else { 488 int addrtype = ipv6_addr_type(&hdr->saddr); 489 490 /* This check is security critical. */ 491 if (addrtype == IPV6_ADDR_ANY || 492 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 493 goto error; 494 if (addrtype & IPV6_ADDR_LINKLOCAL) { 495 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 496 ICMPV6_NOT_NEIGHBOUR, 0); 497 goto error; 498 } 499 } 500 501 mtu = dst_mtu(dst); 502 if (mtu < IPV6_MIN_MTU) 503 mtu = IPV6_MIN_MTU; 504 505 if (skb->len > mtu && !skb_is_gso(skb)) { 506 /* Again, force OUTPUT device used as source address */ 507 skb->dev = dst->dev; 508 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 509 IP6_INC_STATS_BH(net, 510 ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS); 511 IP6_INC_STATS_BH(net, 512 ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS); 513 kfree_skb(skb); 514 return -EMSGSIZE; 515 } 516 517 if (skb_cow(skb, dst->dev->hard_header_len)) { 518 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS); 519 goto drop; 520 } 521 522 hdr = ipv6_hdr(skb); 523 524 /* Mangling hops number delayed to point after skb COW */ 525 526 hdr->hop_limit--; 527 528 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 529 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev, 530 ip6_forward_finish); 531 532 error: 533 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); 534 drop: 535 kfree_skb(skb); 536 return -EINVAL; 537 } 538 539 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 540 { 541 to->pkt_type = from->pkt_type; 542 to->priority = from->priority; 543 to->protocol = from->protocol; 544 skb_dst_drop(to); 545 skb_dst_set(to, dst_clone(skb_dst(from))); 546 to->dev = from->dev; 547 to->mark = from->mark; 548 549 #ifdef CONFIG_NET_SCHED 550 to->tc_index = from->tc_index; 551 #endif 552 nf_copy(to, from); 553 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ 554 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) 555 to->nf_trace = from->nf_trace; 556 #endif 557 skb_copy_secmark(to, from); 558 } 559 560 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 561 { 562 u16 offset = sizeof(struct ipv6hdr); 563 struct ipv6_opt_hdr *exthdr = 564 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 565 unsigned int packet_len = skb->tail - skb->network_header; 566 int found_rhdr = 0; 567 *nexthdr = &ipv6_hdr(skb)->nexthdr; 568 569 while (offset + 1 <= packet_len) { 570 571 switch (**nexthdr) { 572 573 case NEXTHDR_HOP: 574 break; 575 case NEXTHDR_ROUTING: 576 found_rhdr = 1; 577 break; 578 case NEXTHDR_DEST: 579 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE) 580 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 581 break; 582 #endif 583 if (found_rhdr) 584 return offset; 585 break; 586 default : 587 return offset; 588 } 589 590 offset += ipv6_optlen(exthdr); 591 *nexthdr = &exthdr->nexthdr; 592 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 593 offset); 594 } 595 596 return offset; 597 } 598 599 void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt) 600 { 601 static atomic_t ipv6_fragmentation_id; 602 int old, new; 603 604 if (rt && !(rt->dst.flags & DST_NOPEER)) { 605 struct inet_peer *peer; 606 607 if (!rt->rt6i_peer) 608 rt6_bind_peer(rt, 1); 609 peer = rt->rt6i_peer; 610 if (peer) { 611 fhdr->identification = htonl(inet_getid(peer, 0)); 612 return; 613 } 614 } 615 do { 616 old = atomic_read(&ipv6_fragmentation_id); 617 new = old + 1; 618 if (!new) 619 new = 1; 620 } while (atomic_cmpxchg(&ipv6_fragmentation_id, old, new) != old); 621 fhdr->identification = htonl(new); 622 } 623 624 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 625 { 626 struct sk_buff *frag; 627 struct rt6_info *rt = (struct rt6_info*)skb_dst(skb); 628 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 629 struct ipv6hdr *tmp_hdr; 630 struct frag_hdr *fh; 631 unsigned int mtu, hlen, left, len; 632 int hroom, troom; 633 __be32 frag_id = 0; 634 int ptr, offset = 0, err=0; 635 u8 *prevhdr, nexthdr = 0; 636 struct net *net = dev_net(skb_dst(skb)->dev); 637 638 hlen = ip6_find_1stfragopt(skb, &prevhdr); 639 nexthdr = *prevhdr; 640 641 mtu = ip6_skb_dst_mtu(skb); 642 643 /* We must not fragment if the socket is set to force MTU discovery 644 * or if the skb it not generated by a local socket. 645 */ 646 if (unlikely(!skb->local_df && skb->len > mtu)) { 647 if (skb->sk && dst_allfrag(skb_dst(skb))) 648 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 649 650 skb->dev = skb_dst(skb)->dev; 651 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 652 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 653 IPSTATS_MIB_FRAGFAILS); 654 kfree_skb(skb); 655 return -EMSGSIZE; 656 } 657 658 if (np && np->frag_size < mtu) { 659 if (np->frag_size) 660 mtu = np->frag_size; 661 } 662 mtu -= hlen + sizeof(struct frag_hdr); 663 664 if (skb_has_frag_list(skb)) { 665 int first_len = skb_pagelen(skb); 666 struct sk_buff *frag2; 667 668 if (first_len - hlen > mtu || 669 ((first_len - hlen) & 7) || 670 skb_cloned(skb)) 671 goto slow_path; 672 673 skb_walk_frags(skb, frag) { 674 /* Correct geometry. */ 675 if (frag->len > mtu || 676 ((frag->len & 7) && frag->next) || 677 skb_headroom(frag) < hlen) 678 goto slow_path_clean; 679 680 /* Partially cloned skb? */ 681 if (skb_shared(frag)) 682 goto slow_path_clean; 683 684 BUG_ON(frag->sk); 685 if (skb->sk) { 686 frag->sk = skb->sk; 687 frag->destructor = sock_wfree; 688 } 689 skb->truesize -= frag->truesize; 690 } 691 692 err = 0; 693 offset = 0; 694 frag = skb_shinfo(skb)->frag_list; 695 skb_frag_list_init(skb); 696 /* BUILD HEADER */ 697 698 *prevhdr = NEXTHDR_FRAGMENT; 699 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 700 if (!tmp_hdr) { 701 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 702 IPSTATS_MIB_FRAGFAILS); 703 return -ENOMEM; 704 } 705 706 __skb_pull(skb, hlen); 707 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 708 __skb_push(skb, hlen); 709 skb_reset_network_header(skb); 710 memcpy(skb_network_header(skb), tmp_hdr, hlen); 711 712 ipv6_select_ident(fh, rt); 713 fh->nexthdr = nexthdr; 714 fh->reserved = 0; 715 fh->frag_off = htons(IP6_MF); 716 frag_id = fh->identification; 717 718 first_len = skb_pagelen(skb); 719 skb->data_len = first_len - skb_headlen(skb); 720 skb->len = first_len; 721 ipv6_hdr(skb)->payload_len = htons(first_len - 722 sizeof(struct ipv6hdr)); 723 724 dst_hold(&rt->dst); 725 726 for (;;) { 727 /* Prepare header of the next frame, 728 * before previous one went down. */ 729 if (frag) { 730 frag->ip_summed = CHECKSUM_NONE; 731 skb_reset_transport_header(frag); 732 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 733 __skb_push(frag, hlen); 734 skb_reset_network_header(frag); 735 memcpy(skb_network_header(frag), tmp_hdr, 736 hlen); 737 offset += skb->len - hlen - sizeof(struct frag_hdr); 738 fh->nexthdr = nexthdr; 739 fh->reserved = 0; 740 fh->frag_off = htons(offset); 741 if (frag->next != NULL) 742 fh->frag_off |= htons(IP6_MF); 743 fh->identification = frag_id; 744 ipv6_hdr(frag)->payload_len = 745 htons(frag->len - 746 sizeof(struct ipv6hdr)); 747 ip6_copy_metadata(frag, skb); 748 } 749 750 err = output(skb); 751 if(!err) 752 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 753 IPSTATS_MIB_FRAGCREATES); 754 755 if (err || !frag) 756 break; 757 758 skb = frag; 759 frag = skb->next; 760 skb->next = NULL; 761 } 762 763 kfree(tmp_hdr); 764 765 if (err == 0) { 766 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 767 IPSTATS_MIB_FRAGOKS); 768 dst_release(&rt->dst); 769 return 0; 770 } 771 772 while (frag) { 773 skb = frag->next; 774 kfree_skb(frag); 775 frag = skb; 776 } 777 778 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 779 IPSTATS_MIB_FRAGFAILS); 780 dst_release(&rt->dst); 781 return err; 782 783 slow_path_clean: 784 skb_walk_frags(skb, frag2) { 785 if (frag2 == frag) 786 break; 787 frag2->sk = NULL; 788 frag2->destructor = NULL; 789 skb->truesize += frag2->truesize; 790 } 791 } 792 793 slow_path: 794 if ((skb->ip_summed == CHECKSUM_PARTIAL) && 795 skb_checksum_help(skb)) 796 goto fail; 797 798 left = skb->len - hlen; /* Space per frame */ 799 ptr = hlen; /* Where to start from */ 800 801 /* 802 * Fragment the datagram. 803 */ 804 805 *prevhdr = NEXTHDR_FRAGMENT; 806 hroom = LL_RESERVED_SPACE(rt->dst.dev); 807 troom = rt->dst.dev->needed_tailroom; 808 809 /* 810 * Keep copying data until we run out. 811 */ 812 while(left > 0) { 813 len = left; 814 /* IF: it doesn't fit, use 'mtu' - the data space left */ 815 if (len > mtu) 816 len = mtu; 817 /* IF: we are not sending up to and including the packet end 818 then align the next start on an eight byte boundary */ 819 if (len < left) { 820 len &= ~7; 821 } 822 /* 823 * Allocate buffer. 824 */ 825 826 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 827 hroom + troom, GFP_ATOMIC)) == NULL) { 828 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 829 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 830 IPSTATS_MIB_FRAGFAILS); 831 err = -ENOMEM; 832 goto fail; 833 } 834 835 /* 836 * Set up data on packet 837 */ 838 839 ip6_copy_metadata(frag, skb); 840 skb_reserve(frag, hroom); 841 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 842 skb_reset_network_header(frag); 843 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 844 frag->transport_header = (frag->network_header + hlen + 845 sizeof(struct frag_hdr)); 846 847 /* 848 * Charge the memory for the fragment to any owner 849 * it might possess 850 */ 851 if (skb->sk) 852 skb_set_owner_w(frag, skb->sk); 853 854 /* 855 * Copy the packet header into the new buffer. 856 */ 857 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 858 859 /* 860 * Build fragment header. 861 */ 862 fh->nexthdr = nexthdr; 863 fh->reserved = 0; 864 if (!frag_id) { 865 ipv6_select_ident(fh, rt); 866 frag_id = fh->identification; 867 } else 868 fh->identification = frag_id; 869 870 /* 871 * Copy a block of the IP datagram. 872 */ 873 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len)) 874 BUG(); 875 left -= len; 876 877 fh->frag_off = htons(offset); 878 if (left > 0) 879 fh->frag_off |= htons(IP6_MF); 880 ipv6_hdr(frag)->payload_len = htons(frag->len - 881 sizeof(struct ipv6hdr)); 882 883 ptr += len; 884 offset += len; 885 886 /* 887 * Put this fragment into the sending queue. 888 */ 889 err = output(frag); 890 if (err) 891 goto fail; 892 893 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 894 IPSTATS_MIB_FRAGCREATES); 895 } 896 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 897 IPSTATS_MIB_FRAGOKS); 898 consume_skb(skb); 899 return err; 900 901 fail: 902 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 903 IPSTATS_MIB_FRAGFAILS); 904 kfree_skb(skb); 905 return err; 906 } 907 908 static inline int ip6_rt_check(const struct rt6key *rt_key, 909 const struct in6_addr *fl_addr, 910 const struct in6_addr *addr_cache) 911 { 912 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 913 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)); 914 } 915 916 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 917 struct dst_entry *dst, 918 const struct flowi6 *fl6) 919 { 920 struct ipv6_pinfo *np = inet6_sk(sk); 921 struct rt6_info *rt = (struct rt6_info *)dst; 922 923 if (!dst) 924 goto out; 925 926 /* Yes, checking route validity in not connected 927 * case is not very simple. Take into account, 928 * that we do not support routing by source, TOS, 929 * and MSG_DONTROUTE --ANK (980726) 930 * 931 * 1. ip6_rt_check(): If route was host route, 932 * check that cached destination is current. 933 * If it is network route, we still may 934 * check its validity using saved pointer 935 * to the last used address: daddr_cache. 936 * We do not want to save whole address now, 937 * (because main consumer of this service 938 * is tcp, which has not this problem), 939 * so that the last trick works only on connected 940 * sockets. 941 * 2. oif also should be the same. 942 */ 943 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 944 #ifdef CONFIG_IPV6_SUBTREES 945 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 946 #endif 947 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 948 dst_release(dst); 949 dst = NULL; 950 } 951 952 out: 953 return dst; 954 } 955 956 static int ip6_dst_lookup_tail(struct sock *sk, 957 struct dst_entry **dst, struct flowi6 *fl6) 958 { 959 struct net *net = sock_net(sk); 960 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 961 struct neighbour *n; 962 #endif 963 int err; 964 965 if (*dst == NULL) 966 *dst = ip6_route_output(net, sk, fl6); 967 968 if ((err = (*dst)->error)) 969 goto out_err_release; 970 971 if (ipv6_addr_any(&fl6->saddr)) { 972 struct rt6_info *rt = (struct rt6_info *) *dst; 973 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 974 sk ? inet6_sk(sk)->srcprefs : 0, 975 &fl6->saddr); 976 if (err) 977 goto out_err_release; 978 } 979 980 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 981 /* 982 * Here if the dst entry we've looked up 983 * has a neighbour entry that is in the INCOMPLETE 984 * state and the src address from the flow is 985 * marked as OPTIMISTIC, we release the found 986 * dst entry and replace it instead with the 987 * dst entry of the nexthop router 988 */ 989 rcu_read_lock(); 990 n = dst_get_neighbour_noref(*dst); 991 if (n && !(n->nud_state & NUD_VALID)) { 992 struct inet6_ifaddr *ifp; 993 struct flowi6 fl_gw6; 994 int redirect; 995 996 rcu_read_unlock(); 997 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 998 (*dst)->dev, 1); 999 1000 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 1001 if (ifp) 1002 in6_ifa_put(ifp); 1003 1004 if (redirect) { 1005 /* 1006 * We need to get the dst entry for the 1007 * default router instead 1008 */ 1009 dst_release(*dst); 1010 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 1011 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 1012 *dst = ip6_route_output(net, sk, &fl_gw6); 1013 if ((err = (*dst)->error)) 1014 goto out_err_release; 1015 } 1016 } else { 1017 rcu_read_unlock(); 1018 } 1019 #endif 1020 1021 return 0; 1022 1023 out_err_release: 1024 if (err == -ENETUNREACH) 1025 IP6_INC_STATS_BH(net, NULL, IPSTATS_MIB_OUTNOROUTES); 1026 dst_release(*dst); 1027 *dst = NULL; 1028 return err; 1029 } 1030 1031 /** 1032 * ip6_dst_lookup - perform route lookup on flow 1033 * @sk: socket which provides route info 1034 * @dst: pointer to dst_entry * for result 1035 * @fl6: flow to lookup 1036 * 1037 * This function performs a route lookup on the given flow. 1038 * 1039 * It returns zero on success, or a standard errno code on error. 1040 */ 1041 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6) 1042 { 1043 *dst = NULL; 1044 return ip6_dst_lookup_tail(sk, dst, fl6); 1045 } 1046 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 1047 1048 /** 1049 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 1050 * @sk: socket which provides route info 1051 * @fl6: flow to lookup 1052 * @final_dst: final destination address for ipsec lookup 1053 * @can_sleep: we are in a sleepable context 1054 * 1055 * This function performs a route lookup on the given flow. 1056 * 1057 * It returns a valid dst pointer on success, or a pointer encoded 1058 * error code. 1059 */ 1060 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1061 const struct in6_addr *final_dst, 1062 bool can_sleep) 1063 { 1064 struct dst_entry *dst = NULL; 1065 int err; 1066 1067 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1068 if (err) 1069 return ERR_PTR(err); 1070 if (final_dst) 1071 fl6->daddr = *final_dst; 1072 if (can_sleep) 1073 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP; 1074 1075 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1076 } 1077 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1078 1079 /** 1080 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1081 * @sk: socket which provides the dst cache and route info 1082 * @fl6: flow to lookup 1083 * @final_dst: final destination address for ipsec lookup 1084 * @can_sleep: we are in a sleepable context 1085 * 1086 * This function performs a route lookup on the given flow with the 1087 * possibility of using the cached route in the socket if it is valid. 1088 * It will take the socket dst lock when operating on the dst cache. 1089 * As a result, this function can only be used in process context. 1090 * 1091 * It returns a valid dst pointer on success, or a pointer encoded 1092 * error code. 1093 */ 1094 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1095 const struct in6_addr *final_dst, 1096 bool can_sleep) 1097 { 1098 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1099 int err; 1100 1101 dst = ip6_sk_dst_check(sk, dst, fl6); 1102 1103 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1104 if (err) 1105 return ERR_PTR(err); 1106 if (final_dst) 1107 fl6->daddr = *final_dst; 1108 if (can_sleep) 1109 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP; 1110 1111 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1112 } 1113 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1114 1115 static inline int ip6_ufo_append_data(struct sock *sk, 1116 int getfrag(void *from, char *to, int offset, int len, 1117 int odd, struct sk_buff *skb), 1118 void *from, int length, int hh_len, int fragheaderlen, 1119 int transhdrlen, int mtu,unsigned int flags, 1120 struct rt6_info *rt) 1121 1122 { 1123 struct sk_buff *skb; 1124 int err; 1125 1126 /* There is support for UDP large send offload by network 1127 * device, so create one single skb packet containing complete 1128 * udp datagram 1129 */ 1130 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 1131 skb = sock_alloc_send_skb(sk, 1132 hh_len + fragheaderlen + transhdrlen + 20, 1133 (flags & MSG_DONTWAIT), &err); 1134 if (skb == NULL) 1135 return err; 1136 1137 /* reserve space for Hardware header */ 1138 skb_reserve(skb, hh_len); 1139 1140 /* create space for UDP/IP header */ 1141 skb_put(skb,fragheaderlen + transhdrlen); 1142 1143 /* initialize network header pointer */ 1144 skb_reset_network_header(skb); 1145 1146 /* initialize protocol header pointer */ 1147 skb->transport_header = skb->network_header + fragheaderlen; 1148 1149 skb->ip_summed = CHECKSUM_PARTIAL; 1150 skb->csum = 0; 1151 } 1152 1153 err = skb_append_datato_frags(sk,skb, getfrag, from, 1154 (length - transhdrlen)); 1155 if (!err) { 1156 struct frag_hdr fhdr; 1157 1158 /* Specify the length of each IPv6 datagram fragment. 1159 * It has to be a multiple of 8. 1160 */ 1161 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1162 sizeof(struct frag_hdr)) & ~7; 1163 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1164 ipv6_select_ident(&fhdr, rt); 1165 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 1166 __skb_queue_tail(&sk->sk_write_queue, skb); 1167 1168 return 0; 1169 } 1170 /* There is not enough support do UPD LSO, 1171 * so follow normal path 1172 */ 1173 kfree_skb(skb); 1174 1175 return err; 1176 } 1177 1178 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1179 gfp_t gfp) 1180 { 1181 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1182 } 1183 1184 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1185 gfp_t gfp) 1186 { 1187 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1188 } 1189 1190 static void ip6_append_data_mtu(int *mtu, 1191 int *maxfraglen, 1192 unsigned int fragheaderlen, 1193 struct sk_buff *skb, 1194 struct rt6_info *rt) 1195 { 1196 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1197 if (skb == NULL) { 1198 /* first fragment, reserve header_len */ 1199 *mtu = *mtu - rt->dst.header_len; 1200 1201 } else { 1202 /* 1203 * this fragment is not first, the headers 1204 * space is regarded as data space. 1205 */ 1206 *mtu = dst_mtu(rt->dst.path); 1207 } 1208 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1209 + fragheaderlen - sizeof(struct frag_hdr); 1210 } 1211 } 1212 1213 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 1214 int offset, int len, int odd, struct sk_buff *skb), 1215 void *from, int length, int transhdrlen, 1216 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1217 struct rt6_info *rt, unsigned int flags, int dontfrag) 1218 { 1219 struct inet_sock *inet = inet_sk(sk); 1220 struct ipv6_pinfo *np = inet6_sk(sk); 1221 struct inet_cork *cork; 1222 struct sk_buff *skb, *skb_prev = NULL; 1223 unsigned int maxfraglen, fragheaderlen; 1224 int exthdrlen; 1225 int dst_exthdrlen; 1226 int hh_len; 1227 int mtu; 1228 int copy; 1229 int err; 1230 int offset = 0; 1231 __u8 tx_flags = 0; 1232 1233 if (flags&MSG_PROBE) 1234 return 0; 1235 cork = &inet->cork.base; 1236 if (skb_queue_empty(&sk->sk_write_queue)) { 1237 /* 1238 * setup for corking 1239 */ 1240 if (opt) { 1241 if (WARN_ON(np->cork.opt)) 1242 return -EINVAL; 1243 1244 np->cork.opt = kmalloc(opt->tot_len, sk->sk_allocation); 1245 if (unlikely(np->cork.opt == NULL)) 1246 return -ENOBUFS; 1247 1248 np->cork.opt->tot_len = opt->tot_len; 1249 np->cork.opt->opt_flen = opt->opt_flen; 1250 np->cork.opt->opt_nflen = opt->opt_nflen; 1251 1252 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1253 sk->sk_allocation); 1254 if (opt->dst0opt && !np->cork.opt->dst0opt) 1255 return -ENOBUFS; 1256 1257 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1258 sk->sk_allocation); 1259 if (opt->dst1opt && !np->cork.opt->dst1opt) 1260 return -ENOBUFS; 1261 1262 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt, 1263 sk->sk_allocation); 1264 if (opt->hopopt && !np->cork.opt->hopopt) 1265 return -ENOBUFS; 1266 1267 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1268 sk->sk_allocation); 1269 if (opt->srcrt && !np->cork.opt->srcrt) 1270 return -ENOBUFS; 1271 1272 /* need source address above miyazawa*/ 1273 } 1274 dst_hold(&rt->dst); 1275 cork->dst = &rt->dst; 1276 inet->cork.fl.u.ip6 = *fl6; 1277 np->cork.hop_limit = hlimit; 1278 np->cork.tclass = tclass; 1279 if (rt->dst.flags & DST_XFRM_TUNNEL) 1280 mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ? 1281 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1282 else 1283 mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ? 1284 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1285 if (np->frag_size < mtu) { 1286 if (np->frag_size) 1287 mtu = np->frag_size; 1288 } 1289 cork->fragsize = mtu; 1290 if (dst_allfrag(rt->dst.path)) 1291 cork->flags |= IPCORK_ALLFRAG; 1292 cork->length = 0; 1293 sk->sk_sndmsg_page = NULL; 1294 sk->sk_sndmsg_off = 0; 1295 exthdrlen = (opt ? opt->opt_flen : 0) - rt->rt6i_nfheader_len; 1296 length += exthdrlen; 1297 transhdrlen += exthdrlen; 1298 dst_exthdrlen = rt->dst.header_len; 1299 } else { 1300 rt = (struct rt6_info *)cork->dst; 1301 fl6 = &inet->cork.fl.u.ip6; 1302 opt = np->cork.opt; 1303 transhdrlen = 0; 1304 exthdrlen = 0; 1305 dst_exthdrlen = 0; 1306 mtu = cork->fragsize; 1307 } 1308 1309 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1310 1311 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1312 (opt ? opt->opt_nflen : 0); 1313 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); 1314 1315 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1316 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { 1317 ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen); 1318 return -EMSGSIZE; 1319 } 1320 } 1321 1322 /* For UDP, check if TX timestamp is enabled */ 1323 if (sk->sk_type == SOCK_DGRAM) { 1324 err = sock_tx_timestamp(sk, &tx_flags); 1325 if (err) 1326 goto error; 1327 } 1328 1329 /* 1330 * Let's try using as much space as possible. 1331 * Use MTU if total length of the message fits into the MTU. 1332 * Otherwise, we need to reserve fragment header and 1333 * fragment alignment (= 8-15 octects, in total). 1334 * 1335 * Note that we may need to "move" the data from the tail of 1336 * of the buffer to the new fragment when we split 1337 * the message. 1338 * 1339 * FIXME: It may be fragmented into multiple chunks 1340 * at once if non-fragmentable extension headers 1341 * are too large. 1342 * --yoshfuji 1343 */ 1344 1345 cork->length += length; 1346 if (length > mtu) { 1347 int proto = sk->sk_protocol; 1348 if (dontfrag && (proto == IPPROTO_UDP || proto == IPPROTO_RAW)){ 1349 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen); 1350 return -EMSGSIZE; 1351 } 1352 1353 if (proto == IPPROTO_UDP && 1354 (rt->dst.dev->features & NETIF_F_UFO)) { 1355 1356 err = ip6_ufo_append_data(sk, getfrag, from, length, 1357 hh_len, fragheaderlen, 1358 transhdrlen, mtu, flags, rt); 1359 if (err) 1360 goto error; 1361 return 0; 1362 } 1363 } 1364 1365 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1366 goto alloc_new_skb; 1367 1368 while (length > 0) { 1369 /* Check if the remaining data fits into current packet. */ 1370 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1371 if (copy < length) 1372 copy = maxfraglen - skb->len; 1373 1374 if (copy <= 0) { 1375 char *data; 1376 unsigned int datalen; 1377 unsigned int fraglen; 1378 unsigned int fraggap; 1379 unsigned int alloclen; 1380 alloc_new_skb: 1381 /* There's no room in the current skb */ 1382 if (skb) 1383 fraggap = skb->len - maxfraglen; 1384 else 1385 fraggap = 0; 1386 /* update mtu and maxfraglen if necessary */ 1387 if (skb == NULL || skb_prev == NULL) 1388 ip6_append_data_mtu(&mtu, &maxfraglen, 1389 fragheaderlen, skb, rt); 1390 1391 skb_prev = skb; 1392 1393 /* 1394 * If remaining data exceeds the mtu, 1395 * we know we need more fragment(s). 1396 */ 1397 datalen = length + fraggap; 1398 1399 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1400 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1401 if ((flags & MSG_MORE) && 1402 !(rt->dst.dev->features&NETIF_F_SG)) 1403 alloclen = mtu; 1404 else 1405 alloclen = datalen + fragheaderlen; 1406 1407 alloclen += dst_exthdrlen; 1408 1409 if (datalen != length + fraggap) { 1410 /* 1411 * this is not the last fragment, the trailer 1412 * space is regarded as data space. 1413 */ 1414 datalen += rt->dst.trailer_len; 1415 } 1416 1417 alloclen += rt->dst.trailer_len; 1418 fraglen = datalen + fragheaderlen; 1419 1420 /* 1421 * We just reserve space for fragment header. 1422 * Note: this may be overallocation if the message 1423 * (without MSG_MORE) fits into the MTU. 1424 */ 1425 alloclen += sizeof(struct frag_hdr); 1426 1427 if (transhdrlen) { 1428 skb = sock_alloc_send_skb(sk, 1429 alloclen + hh_len, 1430 (flags & MSG_DONTWAIT), &err); 1431 } else { 1432 skb = NULL; 1433 if (atomic_read(&sk->sk_wmem_alloc) <= 1434 2 * sk->sk_sndbuf) 1435 skb = sock_wmalloc(sk, 1436 alloclen + hh_len, 1, 1437 sk->sk_allocation); 1438 if (unlikely(skb == NULL)) 1439 err = -ENOBUFS; 1440 else { 1441 /* Only the initial fragment 1442 * is time stamped. 1443 */ 1444 tx_flags = 0; 1445 } 1446 } 1447 if (skb == NULL) 1448 goto error; 1449 /* 1450 * Fill in the control structures 1451 */ 1452 skb->ip_summed = CHECKSUM_NONE; 1453 skb->csum = 0; 1454 /* reserve for fragmentation and ipsec header */ 1455 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1456 dst_exthdrlen); 1457 1458 if (sk->sk_type == SOCK_DGRAM) 1459 skb_shinfo(skb)->tx_flags = tx_flags; 1460 1461 /* 1462 * Find where to start putting bytes 1463 */ 1464 data = skb_put(skb, fraglen); 1465 skb_set_network_header(skb, exthdrlen); 1466 data += fragheaderlen; 1467 skb->transport_header = (skb->network_header + 1468 fragheaderlen); 1469 if (fraggap) { 1470 skb->csum = skb_copy_and_csum_bits( 1471 skb_prev, maxfraglen, 1472 data + transhdrlen, fraggap, 0); 1473 skb_prev->csum = csum_sub(skb_prev->csum, 1474 skb->csum); 1475 data += fraggap; 1476 pskb_trim_unique(skb_prev, maxfraglen); 1477 } 1478 copy = datalen - transhdrlen - fraggap; 1479 1480 if (copy < 0) { 1481 err = -EINVAL; 1482 kfree_skb(skb); 1483 goto error; 1484 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1485 err = -EFAULT; 1486 kfree_skb(skb); 1487 goto error; 1488 } 1489 1490 offset += copy; 1491 length -= datalen - fraggap; 1492 transhdrlen = 0; 1493 exthdrlen = 0; 1494 dst_exthdrlen = 0; 1495 1496 /* 1497 * Put the packet on the pending queue 1498 */ 1499 __skb_queue_tail(&sk->sk_write_queue, skb); 1500 continue; 1501 } 1502 1503 if (copy > length) 1504 copy = length; 1505 1506 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1507 unsigned int off; 1508 1509 off = skb->len; 1510 if (getfrag(from, skb_put(skb, copy), 1511 offset, copy, off, skb) < 0) { 1512 __skb_trim(skb, off); 1513 err = -EFAULT; 1514 goto error; 1515 } 1516 } else { 1517 int i = skb_shinfo(skb)->nr_frags; 1518 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1519 struct page *page = sk->sk_sndmsg_page; 1520 int off = sk->sk_sndmsg_off; 1521 unsigned int left; 1522 1523 if (page && (left = PAGE_SIZE - off) > 0) { 1524 if (copy >= left) 1525 copy = left; 1526 if (page != skb_frag_page(frag)) { 1527 if (i == MAX_SKB_FRAGS) { 1528 err = -EMSGSIZE; 1529 goto error; 1530 } 1531 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1532 skb_frag_ref(skb, i); 1533 frag = &skb_shinfo(skb)->frags[i]; 1534 } 1535 } else if(i < MAX_SKB_FRAGS) { 1536 if (copy > PAGE_SIZE) 1537 copy = PAGE_SIZE; 1538 page = alloc_pages(sk->sk_allocation, 0); 1539 if (page == NULL) { 1540 err = -ENOMEM; 1541 goto error; 1542 } 1543 sk->sk_sndmsg_page = page; 1544 sk->sk_sndmsg_off = 0; 1545 1546 skb_fill_page_desc(skb, i, page, 0, 0); 1547 frag = &skb_shinfo(skb)->frags[i]; 1548 } else { 1549 err = -EMSGSIZE; 1550 goto error; 1551 } 1552 if (getfrag(from, 1553 skb_frag_address(frag) + skb_frag_size(frag), 1554 offset, copy, skb->len, skb) < 0) { 1555 err = -EFAULT; 1556 goto error; 1557 } 1558 sk->sk_sndmsg_off += copy; 1559 skb_frag_size_add(frag, copy); 1560 skb->len += copy; 1561 skb->data_len += copy; 1562 skb->truesize += copy; 1563 atomic_add(copy, &sk->sk_wmem_alloc); 1564 } 1565 offset += copy; 1566 length -= copy; 1567 } 1568 return 0; 1569 error: 1570 cork->length -= length; 1571 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1572 return err; 1573 } 1574 EXPORT_SYMBOL_GPL(ip6_append_data); 1575 1576 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np) 1577 { 1578 if (np->cork.opt) { 1579 kfree(np->cork.opt->dst0opt); 1580 kfree(np->cork.opt->dst1opt); 1581 kfree(np->cork.opt->hopopt); 1582 kfree(np->cork.opt->srcrt); 1583 kfree(np->cork.opt); 1584 np->cork.opt = NULL; 1585 } 1586 1587 if (inet->cork.base.dst) { 1588 dst_release(inet->cork.base.dst); 1589 inet->cork.base.dst = NULL; 1590 inet->cork.base.flags &= ~IPCORK_ALLFRAG; 1591 } 1592 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1593 } 1594 1595 int ip6_push_pending_frames(struct sock *sk) 1596 { 1597 struct sk_buff *skb, *tmp_skb; 1598 struct sk_buff **tail_skb; 1599 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1600 struct inet_sock *inet = inet_sk(sk); 1601 struct ipv6_pinfo *np = inet6_sk(sk); 1602 struct net *net = sock_net(sk); 1603 struct ipv6hdr *hdr; 1604 struct ipv6_txoptions *opt = np->cork.opt; 1605 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst; 1606 struct flowi6 *fl6 = &inet->cork.fl.u.ip6; 1607 unsigned char proto = fl6->flowi6_proto; 1608 int err = 0; 1609 1610 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1611 goto out; 1612 tail_skb = &(skb_shinfo(skb)->frag_list); 1613 1614 /* move skb->data to ip header from ext header */ 1615 if (skb->data < skb_network_header(skb)) 1616 __skb_pull(skb, skb_network_offset(skb)); 1617 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1618 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1619 *tail_skb = tmp_skb; 1620 tail_skb = &(tmp_skb->next); 1621 skb->len += tmp_skb->len; 1622 skb->data_len += tmp_skb->len; 1623 skb->truesize += tmp_skb->truesize; 1624 tmp_skb->destructor = NULL; 1625 tmp_skb->sk = NULL; 1626 } 1627 1628 /* Allow local fragmentation. */ 1629 if (np->pmtudisc < IPV6_PMTUDISC_DO) 1630 skb->local_df = 1; 1631 1632 *final_dst = fl6->daddr; 1633 __skb_pull(skb, skb_network_header_len(skb)); 1634 if (opt && opt->opt_flen) 1635 ipv6_push_frag_opts(skb, opt, &proto); 1636 if (opt && opt->opt_nflen) 1637 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1638 1639 skb_push(skb, sizeof(struct ipv6hdr)); 1640 skb_reset_network_header(skb); 1641 hdr = ipv6_hdr(skb); 1642 1643 *(__be32*)hdr = fl6->flowlabel | 1644 htonl(0x60000000 | ((int)np->cork.tclass << 20)); 1645 1646 hdr->hop_limit = np->cork.hop_limit; 1647 hdr->nexthdr = proto; 1648 hdr->saddr = fl6->saddr; 1649 hdr->daddr = *final_dst; 1650 1651 skb->priority = sk->sk_priority; 1652 skb->mark = sk->sk_mark; 1653 1654 skb_dst_set(skb, dst_clone(&rt->dst)); 1655 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1656 if (proto == IPPROTO_ICMPV6) { 1657 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1658 1659 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type); 1660 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS); 1661 } 1662 1663 err = ip6_local_out(skb); 1664 if (err) { 1665 if (err > 0) 1666 err = net_xmit_errno(err); 1667 if (err) 1668 goto error; 1669 } 1670 1671 out: 1672 ip6_cork_release(inet, np); 1673 return err; 1674 error: 1675 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1676 goto out; 1677 } 1678 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1679 1680 void ip6_flush_pending_frames(struct sock *sk) 1681 { 1682 struct sk_buff *skb; 1683 1684 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1685 if (skb_dst(skb)) 1686 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1687 IPSTATS_MIB_OUTDISCARDS); 1688 kfree_skb(skb); 1689 } 1690 1691 ip6_cork_release(inet_sk(sk), inet6_sk(sk)); 1692 } 1693 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1694