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 static int ip6_finish_output2(struct sk_buff *skb) 60 { 61 struct dst_entry *dst = skb_dst(skb); 62 struct net_device *dev = dst->dev; 63 struct neighbour *neigh; 64 struct in6_addr *nexthop; 65 int ret; 66 67 skb->protocol = htons(ETH_P_IPV6); 68 skb->dev = dev; 69 70 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { 71 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 72 73 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) && 74 ((mroute6_socket(dev_net(dev), skb) && 75 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 76 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, 77 &ipv6_hdr(skb)->saddr))) { 78 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 79 80 /* Do not check for IFF_ALLMULTI; multicast routing 81 is not supported in any case. 82 */ 83 if (newskb) 84 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 85 newskb, NULL, newskb->dev, 86 dev_loopback_xmit); 87 88 if (ipv6_hdr(skb)->hop_limit == 0) { 89 IP6_INC_STATS(dev_net(dev), idev, 90 IPSTATS_MIB_OUTDISCARDS); 91 kfree_skb(skb); 92 return 0; 93 } 94 } 95 96 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST, 97 skb->len); 98 99 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <= 100 IPV6_ADDR_SCOPE_NODELOCAL && 101 !(dev->flags & IFF_LOOPBACK)) { 102 kfree_skb(skb); 103 return 0; 104 } 105 } 106 107 rcu_read_lock_bh(); 108 nexthop = rt6_nexthop((struct rt6_info *)dst); 109 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop); 110 if (unlikely(!neigh)) 111 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false); 112 if (!IS_ERR(neigh)) { 113 ret = dst_neigh_output(dst, neigh, skb); 114 rcu_read_unlock_bh(); 115 return ret; 116 } 117 rcu_read_unlock_bh(); 118 119 IP6_INC_STATS(dev_net(dst->dev), 120 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 121 kfree_skb(skb); 122 return -EINVAL; 123 } 124 125 static int ip6_finish_output(struct sk_buff *skb) 126 { 127 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || 128 dst_allfrag(skb_dst(skb)) || 129 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) 130 return ip6_fragment(skb, ip6_finish_output2); 131 else 132 return ip6_finish_output2(skb); 133 } 134 135 int ip6_output(struct sock *sk, struct sk_buff *skb) 136 { 137 struct net_device *dev = skb_dst(skb)->dev; 138 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 139 if (unlikely(idev->cnf.disable_ipv6)) { 140 IP6_INC_STATS(dev_net(dev), idev, 141 IPSTATS_MIB_OUTDISCARDS); 142 kfree_skb(skb); 143 return 0; 144 } 145 146 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev, 147 ip6_finish_output, 148 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 149 } 150 151 /* 152 * xmit an sk_buff (used by TCP, SCTP and DCCP) 153 */ 154 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 156 struct ipv6_txoptions *opt, int tclass) 157 { 158 struct net *net = sock_net(sk); 159 struct ipv6_pinfo *np = inet6_sk(sk); 160 struct in6_addr *first_hop = &fl6->daddr; 161 struct dst_entry *dst = skb_dst(skb); 162 struct ipv6hdr *hdr; 163 u8 proto = fl6->flowi6_proto; 164 int seg_len = skb->len; 165 int hlimit = -1; 166 u32 mtu; 167 168 if (opt) { 169 unsigned int head_room; 170 171 /* First: exthdrs may take lots of space (~8K for now) 172 MAX_HEADER is not enough. 173 */ 174 head_room = opt->opt_nflen + opt->opt_flen; 175 seg_len += head_room; 176 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 177 178 if (skb_headroom(skb) < head_room) { 179 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 180 if (skb2 == NULL) { 181 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 182 IPSTATS_MIB_OUTDISCARDS); 183 kfree_skb(skb); 184 return -ENOBUFS; 185 } 186 consume_skb(skb); 187 skb = skb2; 188 skb_set_owner_w(skb, sk); 189 } 190 if (opt->opt_flen) 191 ipv6_push_frag_opts(skb, opt, &proto); 192 if (opt->opt_nflen) 193 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 194 } 195 196 skb_push(skb, sizeof(struct ipv6hdr)); 197 skb_reset_network_header(skb); 198 hdr = ipv6_hdr(skb); 199 200 /* 201 * Fill in the IPv6 header 202 */ 203 if (np) 204 hlimit = np->hop_limit; 205 if (hlimit < 0) 206 hlimit = ip6_dst_hoplimit(dst); 207 208 ip6_flow_hdr(hdr, tclass, fl6->flowlabel); 209 210 hdr->payload_len = htons(seg_len); 211 hdr->nexthdr = proto; 212 hdr->hop_limit = hlimit; 213 214 hdr->saddr = fl6->saddr; 215 hdr->daddr = *first_hop; 216 217 skb->protocol = htons(ETH_P_IPV6); 218 skb->priority = sk->sk_priority; 219 skb->mark = sk->sk_mark; 220 221 mtu = dst_mtu(dst); 222 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 223 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 224 IPSTATS_MIB_OUT, skb->len); 225 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 226 dst->dev, dst_output); 227 } 228 229 skb->dev = dst->dev; 230 ipv6_local_error(sk, EMSGSIZE, fl6, mtu); 231 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 232 kfree_skb(skb); 233 return -EMSGSIZE; 234 } 235 236 EXPORT_SYMBOL(ip6_xmit); 237 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 239 { 240 struct ip6_ra_chain *ra; 241 struct sock *last = NULL; 242 243 read_lock(&ip6_ra_lock); 244 for (ra = ip6_ra_chain; ra; ra = ra->next) { 245 struct sock *sk = ra->sk; 246 if (sk && ra->sel == sel && 247 (!sk->sk_bound_dev_if || 248 sk->sk_bound_dev_if == skb->dev->ifindex)) { 249 if (last) { 250 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 251 if (skb2) 252 rawv6_rcv(last, skb2); 253 } 254 last = sk; 255 } 256 } 257 258 if (last) { 259 rawv6_rcv(last, skb); 260 read_unlock(&ip6_ra_lock); 261 return 1; 262 } 263 read_unlock(&ip6_ra_lock); 264 return 0; 265 } 266 267 static int ip6_forward_proxy_check(struct sk_buff *skb) 268 { 269 struct ipv6hdr *hdr = ipv6_hdr(skb); 270 u8 nexthdr = hdr->nexthdr; 271 __be16 frag_off; 272 int offset; 273 274 if (ipv6_ext_hdr(nexthdr)) { 275 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 276 if (offset < 0) 277 return 0; 278 } else 279 offset = sizeof(struct ipv6hdr); 280 281 if (nexthdr == IPPROTO_ICMPV6) { 282 struct icmp6hdr *icmp6; 283 284 if (!pskb_may_pull(skb, (skb_network_header(skb) + 285 offset + 1 - skb->data))) 286 return 0; 287 288 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 289 290 switch (icmp6->icmp6_type) { 291 case NDISC_ROUTER_SOLICITATION: 292 case NDISC_ROUTER_ADVERTISEMENT: 293 case NDISC_NEIGHBOUR_SOLICITATION: 294 case NDISC_NEIGHBOUR_ADVERTISEMENT: 295 case NDISC_REDIRECT: 296 /* For reaction involving unicast neighbor discovery 297 * message destined to the proxied address, pass it to 298 * input function. 299 */ 300 return 1; 301 default: 302 break; 303 } 304 } 305 306 /* 307 * The proxying router can't forward traffic sent to a link-local 308 * address, so signal the sender and discard the packet. This 309 * behavior is clarified by the MIPv6 specification. 310 */ 311 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 312 dst_link_failure(skb); 313 return -1; 314 } 315 316 return 0; 317 } 318 319 static inline int ip6_forward_finish(struct sk_buff *skb) 320 { 321 return dst_output(skb); 322 } 323 324 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst) 325 { 326 unsigned int mtu; 327 struct inet6_dev *idev; 328 329 if (dst_metric_locked(dst, RTAX_MTU)) { 330 mtu = dst_metric_raw(dst, RTAX_MTU); 331 if (mtu) 332 return mtu; 333 } 334 335 mtu = IPV6_MIN_MTU; 336 rcu_read_lock(); 337 idev = __in6_dev_get(dst->dev); 338 if (idev) 339 mtu = idev->cnf.mtu6; 340 rcu_read_unlock(); 341 342 return mtu; 343 } 344 345 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 346 { 347 if (skb->len <= mtu) 348 return false; 349 350 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 351 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 352 return true; 353 354 if (skb->ignore_df) 355 return false; 356 357 if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) 358 return false; 359 360 return true; 361 } 362 363 int ip6_forward(struct sk_buff *skb) 364 { 365 struct dst_entry *dst = skb_dst(skb); 366 struct ipv6hdr *hdr = ipv6_hdr(skb); 367 struct inet6_skb_parm *opt = IP6CB(skb); 368 struct net *net = dev_net(dst->dev); 369 u32 mtu; 370 371 if (net->ipv6.devconf_all->forwarding == 0) 372 goto error; 373 374 if (skb->pkt_type != PACKET_HOST) 375 goto drop; 376 377 if (skb_warn_if_lro(skb)) 378 goto drop; 379 380 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 381 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 382 IPSTATS_MIB_INDISCARDS); 383 goto drop; 384 } 385 386 skb_forward_csum(skb); 387 388 /* 389 * We DO NOT make any processing on 390 * RA packets, pushing them to user level AS IS 391 * without ane WARRANTY that application will be able 392 * to interpret them. The reason is that we 393 * cannot make anything clever here. 394 * 395 * We are not end-node, so that if packet contains 396 * AH/ESP, we cannot make anything. 397 * Defragmentation also would be mistake, RA packets 398 * cannot be fragmented, because there is no warranty 399 * that different fragments will go along one path. --ANK 400 */ 401 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 402 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 403 return 0; 404 } 405 406 /* 407 * check and decrement ttl 408 */ 409 if (hdr->hop_limit <= 1) { 410 /* Force OUTPUT device used as source address */ 411 skb->dev = dst->dev; 412 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 413 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 414 IPSTATS_MIB_INHDRERRORS); 415 416 kfree_skb(skb); 417 return -ETIMEDOUT; 418 } 419 420 /* XXX: idev->cnf.proxy_ndp? */ 421 if (net->ipv6.devconf_all->proxy_ndp && 422 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 423 int proxied = ip6_forward_proxy_check(skb); 424 if (proxied > 0) 425 return ip6_input(skb); 426 else if (proxied < 0) { 427 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 428 IPSTATS_MIB_INDISCARDS); 429 goto drop; 430 } 431 } 432 433 if (!xfrm6_route_forward(skb)) { 434 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 435 IPSTATS_MIB_INDISCARDS); 436 goto drop; 437 } 438 dst = skb_dst(skb); 439 440 /* IPv6 specs say nothing about it, but it is clear that we cannot 441 send redirects to source routed frames. 442 We don't send redirects to frames decapsulated from IPsec. 443 */ 444 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) { 445 struct in6_addr *target = NULL; 446 struct inet_peer *peer; 447 struct rt6_info *rt; 448 449 /* 450 * incoming and outgoing devices are the same 451 * send a redirect. 452 */ 453 454 rt = (struct rt6_info *) dst; 455 if (rt->rt6i_flags & RTF_GATEWAY) 456 target = &rt->rt6i_gateway; 457 else 458 target = &hdr->daddr; 459 460 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1); 461 462 /* Limit redirects both by destination (here) 463 and by source (inside ndisc_send_redirect) 464 */ 465 if (inet_peer_xrlim_allow(peer, 1*HZ)) 466 ndisc_send_redirect(skb, target); 467 if (peer) 468 inet_putpeer(peer); 469 } else { 470 int addrtype = ipv6_addr_type(&hdr->saddr); 471 472 /* This check is security critical. */ 473 if (addrtype == IPV6_ADDR_ANY || 474 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 475 goto error; 476 if (addrtype & IPV6_ADDR_LINKLOCAL) { 477 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 478 ICMPV6_NOT_NEIGHBOUR, 0); 479 goto error; 480 } 481 } 482 483 mtu = ip6_dst_mtu_forward(dst); 484 if (mtu < IPV6_MIN_MTU) 485 mtu = IPV6_MIN_MTU; 486 487 if (ip6_pkt_too_big(skb, mtu)) { 488 /* Again, force OUTPUT device used as source address */ 489 skb->dev = dst->dev; 490 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 491 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 492 IPSTATS_MIB_INTOOBIGERRORS); 493 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 494 IPSTATS_MIB_FRAGFAILS); 495 kfree_skb(skb); 496 return -EMSGSIZE; 497 } 498 499 if (skb_cow(skb, dst->dev->hard_header_len)) { 500 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 501 IPSTATS_MIB_OUTDISCARDS); 502 goto drop; 503 } 504 505 hdr = ipv6_hdr(skb); 506 507 /* Mangling hops number delayed to point after skb COW */ 508 509 hdr->hop_limit--; 510 511 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 512 IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 513 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev, 514 ip6_forward_finish); 515 516 error: 517 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); 518 drop: 519 kfree_skb(skb); 520 return -EINVAL; 521 } 522 523 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 524 { 525 to->pkt_type = from->pkt_type; 526 to->priority = from->priority; 527 to->protocol = from->protocol; 528 skb_dst_drop(to); 529 skb_dst_set(to, dst_clone(skb_dst(from))); 530 to->dev = from->dev; 531 to->mark = from->mark; 532 533 #ifdef CONFIG_NET_SCHED 534 to->tc_index = from->tc_index; 535 #endif 536 nf_copy(to, from); 537 skb_copy_secmark(to, from); 538 } 539 540 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 541 { 542 struct sk_buff *frag; 543 struct rt6_info *rt = (struct rt6_info*)skb_dst(skb); 544 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 545 struct ipv6hdr *tmp_hdr; 546 struct frag_hdr *fh; 547 unsigned int mtu, hlen, left, len; 548 int hroom, troom; 549 __be32 frag_id = 0; 550 int ptr, offset = 0, err=0; 551 u8 *prevhdr, nexthdr = 0; 552 struct net *net = dev_net(skb_dst(skb)->dev); 553 554 hlen = ip6_find_1stfragopt(skb, &prevhdr); 555 nexthdr = *prevhdr; 556 557 mtu = ip6_skb_dst_mtu(skb); 558 559 /* We must not fragment if the socket is set to force MTU discovery 560 * or if the skb it not generated by a local socket. 561 */ 562 if (unlikely(!skb->ignore_df && skb->len > mtu) || 563 (IP6CB(skb)->frag_max_size && 564 IP6CB(skb)->frag_max_size > mtu)) { 565 if (skb->sk && dst_allfrag(skb_dst(skb))) 566 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 567 568 skb->dev = skb_dst(skb)->dev; 569 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 570 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 571 IPSTATS_MIB_FRAGFAILS); 572 kfree_skb(skb); 573 return -EMSGSIZE; 574 } 575 576 if (np && np->frag_size < mtu) { 577 if (np->frag_size) 578 mtu = np->frag_size; 579 } 580 mtu -= hlen + sizeof(struct frag_hdr); 581 582 if (skb_has_frag_list(skb)) { 583 int first_len = skb_pagelen(skb); 584 struct sk_buff *frag2; 585 586 if (first_len - hlen > mtu || 587 ((first_len - hlen) & 7) || 588 skb_cloned(skb)) 589 goto slow_path; 590 591 skb_walk_frags(skb, frag) { 592 /* Correct geometry. */ 593 if (frag->len > mtu || 594 ((frag->len & 7) && frag->next) || 595 skb_headroom(frag) < hlen) 596 goto slow_path_clean; 597 598 /* Partially cloned skb? */ 599 if (skb_shared(frag)) 600 goto slow_path_clean; 601 602 BUG_ON(frag->sk); 603 if (skb->sk) { 604 frag->sk = skb->sk; 605 frag->destructor = sock_wfree; 606 } 607 skb->truesize -= frag->truesize; 608 } 609 610 err = 0; 611 offset = 0; 612 frag = skb_shinfo(skb)->frag_list; 613 skb_frag_list_init(skb); 614 /* BUILD HEADER */ 615 616 *prevhdr = NEXTHDR_FRAGMENT; 617 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 618 if (!tmp_hdr) { 619 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 620 IPSTATS_MIB_FRAGFAILS); 621 return -ENOMEM; 622 } 623 624 __skb_pull(skb, hlen); 625 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 626 __skb_push(skb, hlen); 627 skb_reset_network_header(skb); 628 memcpy(skb_network_header(skb), tmp_hdr, hlen); 629 630 ipv6_select_ident(fh, rt); 631 fh->nexthdr = nexthdr; 632 fh->reserved = 0; 633 fh->frag_off = htons(IP6_MF); 634 frag_id = fh->identification; 635 636 first_len = skb_pagelen(skb); 637 skb->data_len = first_len - skb_headlen(skb); 638 skb->len = first_len; 639 ipv6_hdr(skb)->payload_len = htons(first_len - 640 sizeof(struct ipv6hdr)); 641 642 dst_hold(&rt->dst); 643 644 for (;;) { 645 /* Prepare header of the next frame, 646 * before previous one went down. */ 647 if (frag) { 648 frag->ip_summed = CHECKSUM_NONE; 649 skb_reset_transport_header(frag); 650 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 651 __skb_push(frag, hlen); 652 skb_reset_network_header(frag); 653 memcpy(skb_network_header(frag), tmp_hdr, 654 hlen); 655 offset += skb->len - hlen - sizeof(struct frag_hdr); 656 fh->nexthdr = nexthdr; 657 fh->reserved = 0; 658 fh->frag_off = htons(offset); 659 if (frag->next != NULL) 660 fh->frag_off |= htons(IP6_MF); 661 fh->identification = frag_id; 662 ipv6_hdr(frag)->payload_len = 663 htons(frag->len - 664 sizeof(struct ipv6hdr)); 665 ip6_copy_metadata(frag, skb); 666 } 667 668 err = output(skb); 669 if(!err) 670 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 671 IPSTATS_MIB_FRAGCREATES); 672 673 if (err || !frag) 674 break; 675 676 skb = frag; 677 frag = skb->next; 678 skb->next = NULL; 679 } 680 681 kfree(tmp_hdr); 682 683 if (err == 0) { 684 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 685 IPSTATS_MIB_FRAGOKS); 686 ip6_rt_put(rt); 687 return 0; 688 } 689 690 while (frag) { 691 skb = frag->next; 692 kfree_skb(frag); 693 frag = skb; 694 } 695 696 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 697 IPSTATS_MIB_FRAGFAILS); 698 ip6_rt_put(rt); 699 return err; 700 701 slow_path_clean: 702 skb_walk_frags(skb, frag2) { 703 if (frag2 == frag) 704 break; 705 frag2->sk = NULL; 706 frag2->destructor = NULL; 707 skb->truesize += frag2->truesize; 708 } 709 } 710 711 slow_path: 712 if ((skb->ip_summed == CHECKSUM_PARTIAL) && 713 skb_checksum_help(skb)) 714 goto fail; 715 716 left = skb->len - hlen; /* Space per frame */ 717 ptr = hlen; /* Where to start from */ 718 719 /* 720 * Fragment the datagram. 721 */ 722 723 *prevhdr = NEXTHDR_FRAGMENT; 724 hroom = LL_RESERVED_SPACE(rt->dst.dev); 725 troom = rt->dst.dev->needed_tailroom; 726 727 /* 728 * Keep copying data until we run out. 729 */ 730 while(left > 0) { 731 len = left; 732 /* IF: it doesn't fit, use 'mtu' - the data space left */ 733 if (len > mtu) 734 len = mtu; 735 /* IF: we are not sending up to and including the packet end 736 then align the next start on an eight byte boundary */ 737 if (len < left) { 738 len &= ~7; 739 } 740 /* 741 * Allocate buffer. 742 */ 743 744 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 745 hroom + troom, GFP_ATOMIC)) == NULL) { 746 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 747 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 748 IPSTATS_MIB_FRAGFAILS); 749 err = -ENOMEM; 750 goto fail; 751 } 752 753 /* 754 * Set up data on packet 755 */ 756 757 ip6_copy_metadata(frag, skb); 758 skb_reserve(frag, hroom); 759 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 760 skb_reset_network_header(frag); 761 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 762 frag->transport_header = (frag->network_header + hlen + 763 sizeof(struct frag_hdr)); 764 765 /* 766 * Charge the memory for the fragment to any owner 767 * it might possess 768 */ 769 if (skb->sk) 770 skb_set_owner_w(frag, skb->sk); 771 772 /* 773 * Copy the packet header into the new buffer. 774 */ 775 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 776 777 /* 778 * Build fragment header. 779 */ 780 fh->nexthdr = nexthdr; 781 fh->reserved = 0; 782 if (!frag_id) { 783 ipv6_select_ident(fh, rt); 784 frag_id = fh->identification; 785 } else 786 fh->identification = frag_id; 787 788 /* 789 * Copy a block of the IP datagram. 790 */ 791 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len)) 792 BUG(); 793 left -= len; 794 795 fh->frag_off = htons(offset); 796 if (left > 0) 797 fh->frag_off |= htons(IP6_MF); 798 ipv6_hdr(frag)->payload_len = htons(frag->len - 799 sizeof(struct ipv6hdr)); 800 801 ptr += len; 802 offset += len; 803 804 /* 805 * Put this fragment into the sending queue. 806 */ 807 err = output(frag); 808 if (err) 809 goto fail; 810 811 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 812 IPSTATS_MIB_FRAGCREATES); 813 } 814 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 815 IPSTATS_MIB_FRAGOKS); 816 consume_skb(skb); 817 return err; 818 819 fail: 820 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 821 IPSTATS_MIB_FRAGFAILS); 822 kfree_skb(skb); 823 return err; 824 } 825 826 static inline int ip6_rt_check(const struct rt6key *rt_key, 827 const struct in6_addr *fl_addr, 828 const struct in6_addr *addr_cache) 829 { 830 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 831 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)); 832 } 833 834 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 835 struct dst_entry *dst, 836 const struct flowi6 *fl6) 837 { 838 struct ipv6_pinfo *np = inet6_sk(sk); 839 struct rt6_info *rt; 840 841 if (!dst) 842 goto out; 843 844 if (dst->ops->family != AF_INET6) { 845 dst_release(dst); 846 return NULL; 847 } 848 849 rt = (struct rt6_info *)dst; 850 /* Yes, checking route validity in not connected 851 * case is not very simple. Take into account, 852 * that we do not support routing by source, TOS, 853 * and MSG_DONTROUTE --ANK (980726) 854 * 855 * 1. ip6_rt_check(): If route was host route, 856 * check that cached destination is current. 857 * If it is network route, we still may 858 * check its validity using saved pointer 859 * to the last used address: daddr_cache. 860 * We do not want to save whole address now, 861 * (because main consumer of this service 862 * is tcp, which has not this problem), 863 * so that the last trick works only on connected 864 * sockets. 865 * 2. oif also should be the same. 866 */ 867 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 868 #ifdef CONFIG_IPV6_SUBTREES 869 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 870 #endif 871 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 872 dst_release(dst); 873 dst = NULL; 874 } 875 876 out: 877 return dst; 878 } 879 880 static int ip6_dst_lookup_tail(struct sock *sk, 881 struct dst_entry **dst, struct flowi6 *fl6) 882 { 883 struct net *net = sock_net(sk); 884 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 885 struct neighbour *n; 886 struct rt6_info *rt; 887 #endif 888 int err; 889 890 if (*dst == NULL) 891 *dst = ip6_route_output(net, sk, fl6); 892 893 if ((err = (*dst)->error)) 894 goto out_err_release; 895 896 if (ipv6_addr_any(&fl6->saddr)) { 897 struct rt6_info *rt = (struct rt6_info *) *dst; 898 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 899 sk ? inet6_sk(sk)->srcprefs : 0, 900 &fl6->saddr); 901 if (err) 902 goto out_err_release; 903 } 904 905 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 906 /* 907 * Here if the dst entry we've looked up 908 * has a neighbour entry that is in the INCOMPLETE 909 * state and the src address from the flow is 910 * marked as OPTIMISTIC, we release the found 911 * dst entry and replace it instead with the 912 * dst entry of the nexthop router 913 */ 914 rt = (struct rt6_info *) *dst; 915 rcu_read_lock_bh(); 916 n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt)); 917 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 918 rcu_read_unlock_bh(); 919 920 if (err) { 921 struct inet6_ifaddr *ifp; 922 struct flowi6 fl_gw6; 923 int redirect; 924 925 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 926 (*dst)->dev, 1); 927 928 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 929 if (ifp) 930 in6_ifa_put(ifp); 931 932 if (redirect) { 933 /* 934 * We need to get the dst entry for the 935 * default router instead 936 */ 937 dst_release(*dst); 938 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 939 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 940 *dst = ip6_route_output(net, sk, &fl_gw6); 941 if ((err = (*dst)->error)) 942 goto out_err_release; 943 } 944 } 945 #endif 946 947 return 0; 948 949 out_err_release: 950 if (err == -ENETUNREACH) 951 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 952 dst_release(*dst); 953 *dst = NULL; 954 return err; 955 } 956 957 /** 958 * ip6_dst_lookup - perform route lookup on flow 959 * @sk: socket which provides route info 960 * @dst: pointer to dst_entry * for result 961 * @fl6: flow to lookup 962 * 963 * This function performs a route lookup on the given flow. 964 * 965 * It returns zero on success, or a standard errno code on error. 966 */ 967 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6) 968 { 969 *dst = NULL; 970 return ip6_dst_lookup_tail(sk, dst, fl6); 971 } 972 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 973 974 /** 975 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 976 * @sk: socket which provides route info 977 * @fl6: flow to lookup 978 * @final_dst: final destination address for ipsec lookup 979 * 980 * This function performs a route lookup on the given flow. 981 * 982 * It returns a valid dst pointer on success, or a pointer encoded 983 * error code. 984 */ 985 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 986 const struct in6_addr *final_dst) 987 { 988 struct dst_entry *dst = NULL; 989 int err; 990 991 err = ip6_dst_lookup_tail(sk, &dst, fl6); 992 if (err) 993 return ERR_PTR(err); 994 if (final_dst) 995 fl6->daddr = *final_dst; 996 997 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 998 } 999 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1000 1001 /** 1002 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1003 * @sk: socket which provides the dst cache and route info 1004 * @fl6: flow to lookup 1005 * @final_dst: final destination address for ipsec lookup 1006 * 1007 * This function performs a route lookup on the given flow with the 1008 * possibility of using the cached route in the socket if it is valid. 1009 * It will take the socket dst lock when operating on the dst cache. 1010 * As a result, this function can only be used in process context. 1011 * 1012 * It returns a valid dst pointer on success, or a pointer encoded 1013 * error code. 1014 */ 1015 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1016 const struct in6_addr *final_dst) 1017 { 1018 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1019 int err; 1020 1021 dst = ip6_sk_dst_check(sk, dst, fl6); 1022 1023 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1024 if (err) 1025 return ERR_PTR(err); 1026 if (final_dst) 1027 fl6->daddr = *final_dst; 1028 1029 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1030 } 1031 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1032 1033 static inline int ip6_ufo_append_data(struct sock *sk, 1034 int getfrag(void *from, char *to, int offset, int len, 1035 int odd, struct sk_buff *skb), 1036 void *from, int length, int hh_len, int fragheaderlen, 1037 int transhdrlen, int mtu,unsigned int flags, 1038 struct rt6_info *rt) 1039 1040 { 1041 struct sk_buff *skb; 1042 struct frag_hdr fhdr; 1043 int err; 1044 1045 /* There is support for UDP large send offload by network 1046 * device, so create one single skb packet containing complete 1047 * udp datagram 1048 */ 1049 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 1050 skb = sock_alloc_send_skb(sk, 1051 hh_len + fragheaderlen + transhdrlen + 20, 1052 (flags & MSG_DONTWAIT), &err); 1053 if (skb == NULL) 1054 return err; 1055 1056 /* reserve space for Hardware header */ 1057 skb_reserve(skb, hh_len); 1058 1059 /* create space for UDP/IP header */ 1060 skb_put(skb,fragheaderlen + transhdrlen); 1061 1062 /* initialize network header pointer */ 1063 skb_reset_network_header(skb); 1064 1065 /* initialize protocol header pointer */ 1066 skb->transport_header = skb->network_header + fragheaderlen; 1067 1068 skb->protocol = htons(ETH_P_IPV6); 1069 skb->csum = 0; 1070 1071 __skb_queue_tail(&sk->sk_write_queue, skb); 1072 } else if (skb_is_gso(skb)) { 1073 goto append; 1074 } 1075 1076 skb->ip_summed = CHECKSUM_PARTIAL; 1077 /* Specify the length of each IPv6 datagram fragment. 1078 * It has to be a multiple of 8. 1079 */ 1080 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1081 sizeof(struct frag_hdr)) & ~7; 1082 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1083 ipv6_select_ident(&fhdr, rt); 1084 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 1085 1086 append: 1087 return skb_append_datato_frags(sk, skb, getfrag, from, 1088 (length - transhdrlen)); 1089 } 1090 1091 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1092 gfp_t gfp) 1093 { 1094 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1095 } 1096 1097 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1098 gfp_t gfp) 1099 { 1100 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1101 } 1102 1103 static void ip6_append_data_mtu(unsigned int *mtu, 1104 int *maxfraglen, 1105 unsigned int fragheaderlen, 1106 struct sk_buff *skb, 1107 struct rt6_info *rt, 1108 unsigned int orig_mtu) 1109 { 1110 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1111 if (skb == NULL) { 1112 /* first fragment, reserve header_len */ 1113 *mtu = orig_mtu - rt->dst.header_len; 1114 1115 } else { 1116 /* 1117 * this fragment is not first, the headers 1118 * space is regarded as data space. 1119 */ 1120 *mtu = orig_mtu; 1121 } 1122 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1123 + fragheaderlen - sizeof(struct frag_hdr); 1124 } 1125 } 1126 1127 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 1128 int offset, int len, int odd, struct sk_buff *skb), 1129 void *from, int length, int transhdrlen, 1130 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1131 struct rt6_info *rt, unsigned int flags, int dontfrag) 1132 { 1133 struct inet_sock *inet = inet_sk(sk); 1134 struct ipv6_pinfo *np = inet6_sk(sk); 1135 struct inet_cork *cork; 1136 struct sk_buff *skb, *skb_prev = NULL; 1137 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1138 int exthdrlen; 1139 int dst_exthdrlen; 1140 int hh_len; 1141 int copy; 1142 int err; 1143 int offset = 0; 1144 __u8 tx_flags = 0; 1145 1146 if (flags&MSG_PROBE) 1147 return 0; 1148 cork = &inet->cork.base; 1149 if (skb_queue_empty(&sk->sk_write_queue)) { 1150 /* 1151 * setup for corking 1152 */ 1153 if (opt) { 1154 if (WARN_ON(np->cork.opt)) 1155 return -EINVAL; 1156 1157 np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation); 1158 if (unlikely(np->cork.opt == NULL)) 1159 return -ENOBUFS; 1160 1161 np->cork.opt->tot_len = opt->tot_len; 1162 np->cork.opt->opt_flen = opt->opt_flen; 1163 np->cork.opt->opt_nflen = opt->opt_nflen; 1164 1165 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1166 sk->sk_allocation); 1167 if (opt->dst0opt && !np->cork.opt->dst0opt) 1168 return -ENOBUFS; 1169 1170 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1171 sk->sk_allocation); 1172 if (opt->dst1opt && !np->cork.opt->dst1opt) 1173 return -ENOBUFS; 1174 1175 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt, 1176 sk->sk_allocation); 1177 if (opt->hopopt && !np->cork.opt->hopopt) 1178 return -ENOBUFS; 1179 1180 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1181 sk->sk_allocation); 1182 if (opt->srcrt && !np->cork.opt->srcrt) 1183 return -ENOBUFS; 1184 1185 /* need source address above miyazawa*/ 1186 } 1187 dst_hold(&rt->dst); 1188 cork->dst = &rt->dst; 1189 inet->cork.fl.u.ip6 = *fl6; 1190 np->cork.hop_limit = hlimit; 1191 np->cork.tclass = tclass; 1192 if (rt->dst.flags & DST_XFRM_TUNNEL) 1193 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1194 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1195 else 1196 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1197 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1198 if (np->frag_size < mtu) { 1199 if (np->frag_size) 1200 mtu = np->frag_size; 1201 } 1202 cork->fragsize = mtu; 1203 if (dst_allfrag(rt->dst.path)) 1204 cork->flags |= IPCORK_ALLFRAG; 1205 cork->length = 0; 1206 exthdrlen = (opt ? opt->opt_flen : 0); 1207 length += exthdrlen; 1208 transhdrlen += exthdrlen; 1209 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1210 } else { 1211 rt = (struct rt6_info *)cork->dst; 1212 fl6 = &inet->cork.fl.u.ip6; 1213 opt = np->cork.opt; 1214 transhdrlen = 0; 1215 exthdrlen = 0; 1216 dst_exthdrlen = 0; 1217 mtu = cork->fragsize; 1218 } 1219 orig_mtu = mtu; 1220 1221 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1222 1223 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1224 (opt ? opt->opt_nflen : 0); 1225 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1226 sizeof(struct frag_hdr); 1227 1228 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1229 unsigned int maxnonfragsize, headersize; 1230 1231 headersize = sizeof(struct ipv6hdr) + 1232 (opt ? opt->tot_len : 0) + 1233 (dst_allfrag(&rt->dst) ? 1234 sizeof(struct frag_hdr) : 0) + 1235 rt->rt6i_nfheader_len; 1236 1237 if (ip6_sk_ignore_df(sk)) 1238 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1239 else 1240 maxnonfragsize = mtu; 1241 1242 /* dontfrag active */ 1243 if ((cork->length + length > mtu - headersize) && dontfrag && 1244 (sk->sk_protocol == IPPROTO_UDP || 1245 sk->sk_protocol == IPPROTO_RAW)) { 1246 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1247 sizeof(struct ipv6hdr)); 1248 goto emsgsize; 1249 } 1250 1251 if (cork->length + length > maxnonfragsize - headersize) { 1252 emsgsize: 1253 ipv6_local_error(sk, EMSGSIZE, fl6, 1254 mtu - headersize + 1255 sizeof(struct ipv6hdr)); 1256 return -EMSGSIZE; 1257 } 1258 } 1259 1260 /* For UDP, check if TX timestamp is enabled */ 1261 if (sk->sk_type == SOCK_DGRAM) 1262 sock_tx_timestamp(sk, &tx_flags); 1263 1264 /* 1265 * Let's try using as much space as possible. 1266 * Use MTU if total length of the message fits into the MTU. 1267 * Otherwise, we need to reserve fragment header and 1268 * fragment alignment (= 8-15 octects, in total). 1269 * 1270 * Note that we may need to "move" the data from the tail of 1271 * of the buffer to the new fragment when we split 1272 * the message. 1273 * 1274 * FIXME: It may be fragmented into multiple chunks 1275 * at once if non-fragmentable extension headers 1276 * are too large. 1277 * --yoshfuji 1278 */ 1279 1280 skb = skb_peek_tail(&sk->sk_write_queue); 1281 cork->length += length; 1282 if (((length > mtu) || 1283 (skb && skb_is_gso(skb))) && 1284 (sk->sk_protocol == IPPROTO_UDP) && 1285 (rt->dst.dev->features & NETIF_F_UFO)) { 1286 err = ip6_ufo_append_data(sk, getfrag, from, length, 1287 hh_len, fragheaderlen, 1288 transhdrlen, mtu, flags, rt); 1289 if (err) 1290 goto error; 1291 return 0; 1292 } 1293 1294 if (!skb) 1295 goto alloc_new_skb; 1296 1297 while (length > 0) { 1298 /* Check if the remaining data fits into current packet. */ 1299 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1300 if (copy < length) 1301 copy = maxfraglen - skb->len; 1302 1303 if (copy <= 0) { 1304 char *data; 1305 unsigned int datalen; 1306 unsigned int fraglen; 1307 unsigned int fraggap; 1308 unsigned int alloclen; 1309 alloc_new_skb: 1310 /* There's no room in the current skb */ 1311 if (skb) 1312 fraggap = skb->len - maxfraglen; 1313 else 1314 fraggap = 0; 1315 /* update mtu and maxfraglen if necessary */ 1316 if (skb == NULL || skb_prev == NULL) 1317 ip6_append_data_mtu(&mtu, &maxfraglen, 1318 fragheaderlen, skb, rt, 1319 orig_mtu); 1320 1321 skb_prev = skb; 1322 1323 /* 1324 * If remaining data exceeds the mtu, 1325 * we know we need more fragment(s). 1326 */ 1327 datalen = length + fraggap; 1328 1329 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1330 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1331 if ((flags & MSG_MORE) && 1332 !(rt->dst.dev->features&NETIF_F_SG)) 1333 alloclen = mtu; 1334 else 1335 alloclen = datalen + fragheaderlen; 1336 1337 alloclen += dst_exthdrlen; 1338 1339 if (datalen != length + fraggap) { 1340 /* 1341 * this is not the last fragment, the trailer 1342 * space is regarded as data space. 1343 */ 1344 datalen += rt->dst.trailer_len; 1345 } 1346 1347 alloclen += rt->dst.trailer_len; 1348 fraglen = datalen + fragheaderlen; 1349 1350 /* 1351 * We just reserve space for fragment header. 1352 * Note: this may be overallocation if the message 1353 * (without MSG_MORE) fits into the MTU. 1354 */ 1355 alloclen += sizeof(struct frag_hdr); 1356 1357 if (transhdrlen) { 1358 skb = sock_alloc_send_skb(sk, 1359 alloclen + hh_len, 1360 (flags & MSG_DONTWAIT), &err); 1361 } else { 1362 skb = NULL; 1363 if (atomic_read(&sk->sk_wmem_alloc) <= 1364 2 * sk->sk_sndbuf) 1365 skb = sock_wmalloc(sk, 1366 alloclen + hh_len, 1, 1367 sk->sk_allocation); 1368 if (unlikely(skb == NULL)) 1369 err = -ENOBUFS; 1370 else { 1371 /* Only the initial fragment 1372 * is time stamped. 1373 */ 1374 tx_flags = 0; 1375 } 1376 } 1377 if (skb == NULL) 1378 goto error; 1379 /* 1380 * Fill in the control structures 1381 */ 1382 skb->protocol = htons(ETH_P_IPV6); 1383 skb->ip_summed = CHECKSUM_NONE; 1384 skb->csum = 0; 1385 /* reserve for fragmentation and ipsec header */ 1386 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1387 dst_exthdrlen); 1388 1389 if (sk->sk_type == SOCK_DGRAM) 1390 skb_shinfo(skb)->tx_flags = tx_flags; 1391 1392 /* 1393 * Find where to start putting bytes 1394 */ 1395 data = skb_put(skb, fraglen); 1396 skb_set_network_header(skb, exthdrlen); 1397 data += fragheaderlen; 1398 skb->transport_header = (skb->network_header + 1399 fragheaderlen); 1400 if (fraggap) { 1401 skb->csum = skb_copy_and_csum_bits( 1402 skb_prev, maxfraglen, 1403 data + transhdrlen, fraggap, 0); 1404 skb_prev->csum = csum_sub(skb_prev->csum, 1405 skb->csum); 1406 data += fraggap; 1407 pskb_trim_unique(skb_prev, maxfraglen); 1408 } 1409 copy = datalen - transhdrlen - fraggap; 1410 1411 if (copy < 0) { 1412 err = -EINVAL; 1413 kfree_skb(skb); 1414 goto error; 1415 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1416 err = -EFAULT; 1417 kfree_skb(skb); 1418 goto error; 1419 } 1420 1421 offset += copy; 1422 length -= datalen - fraggap; 1423 transhdrlen = 0; 1424 exthdrlen = 0; 1425 dst_exthdrlen = 0; 1426 1427 /* 1428 * Put the packet on the pending queue 1429 */ 1430 __skb_queue_tail(&sk->sk_write_queue, skb); 1431 continue; 1432 } 1433 1434 if (copy > length) 1435 copy = length; 1436 1437 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1438 unsigned int off; 1439 1440 off = skb->len; 1441 if (getfrag(from, skb_put(skb, copy), 1442 offset, copy, off, skb) < 0) { 1443 __skb_trim(skb, off); 1444 err = -EFAULT; 1445 goto error; 1446 } 1447 } else { 1448 int i = skb_shinfo(skb)->nr_frags; 1449 struct page_frag *pfrag = sk_page_frag(sk); 1450 1451 err = -ENOMEM; 1452 if (!sk_page_frag_refill(sk, pfrag)) 1453 goto error; 1454 1455 if (!skb_can_coalesce(skb, i, pfrag->page, 1456 pfrag->offset)) { 1457 err = -EMSGSIZE; 1458 if (i == MAX_SKB_FRAGS) 1459 goto error; 1460 1461 __skb_fill_page_desc(skb, i, pfrag->page, 1462 pfrag->offset, 0); 1463 skb_shinfo(skb)->nr_frags = ++i; 1464 get_page(pfrag->page); 1465 } 1466 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1467 if (getfrag(from, 1468 page_address(pfrag->page) + pfrag->offset, 1469 offset, copy, skb->len, skb) < 0) 1470 goto error_efault; 1471 1472 pfrag->offset += copy; 1473 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1474 skb->len += copy; 1475 skb->data_len += copy; 1476 skb->truesize += copy; 1477 atomic_add(copy, &sk->sk_wmem_alloc); 1478 } 1479 offset += copy; 1480 length -= copy; 1481 } 1482 1483 return 0; 1484 1485 error_efault: 1486 err = -EFAULT; 1487 error: 1488 cork->length -= length; 1489 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1490 return err; 1491 } 1492 EXPORT_SYMBOL_GPL(ip6_append_data); 1493 1494 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np) 1495 { 1496 if (np->cork.opt) { 1497 kfree(np->cork.opt->dst0opt); 1498 kfree(np->cork.opt->dst1opt); 1499 kfree(np->cork.opt->hopopt); 1500 kfree(np->cork.opt->srcrt); 1501 kfree(np->cork.opt); 1502 np->cork.opt = NULL; 1503 } 1504 1505 if (inet->cork.base.dst) { 1506 dst_release(inet->cork.base.dst); 1507 inet->cork.base.dst = NULL; 1508 inet->cork.base.flags &= ~IPCORK_ALLFRAG; 1509 } 1510 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1511 } 1512 1513 int ip6_push_pending_frames(struct sock *sk) 1514 { 1515 struct sk_buff *skb, *tmp_skb; 1516 struct sk_buff **tail_skb; 1517 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1518 struct inet_sock *inet = inet_sk(sk); 1519 struct ipv6_pinfo *np = inet6_sk(sk); 1520 struct net *net = sock_net(sk); 1521 struct ipv6hdr *hdr; 1522 struct ipv6_txoptions *opt = np->cork.opt; 1523 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst; 1524 struct flowi6 *fl6 = &inet->cork.fl.u.ip6; 1525 unsigned char proto = fl6->flowi6_proto; 1526 int err = 0; 1527 1528 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1529 goto out; 1530 tail_skb = &(skb_shinfo(skb)->frag_list); 1531 1532 /* move skb->data to ip header from ext header */ 1533 if (skb->data < skb_network_header(skb)) 1534 __skb_pull(skb, skb_network_offset(skb)); 1535 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1536 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1537 *tail_skb = tmp_skb; 1538 tail_skb = &(tmp_skb->next); 1539 skb->len += tmp_skb->len; 1540 skb->data_len += tmp_skb->len; 1541 skb->truesize += tmp_skb->truesize; 1542 tmp_skb->destructor = NULL; 1543 tmp_skb->sk = NULL; 1544 } 1545 1546 /* Allow local fragmentation. */ 1547 skb->ignore_df = ip6_sk_ignore_df(sk); 1548 1549 *final_dst = fl6->daddr; 1550 __skb_pull(skb, skb_network_header_len(skb)); 1551 if (opt && opt->opt_flen) 1552 ipv6_push_frag_opts(skb, opt, &proto); 1553 if (opt && opt->opt_nflen) 1554 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1555 1556 skb_push(skb, sizeof(struct ipv6hdr)); 1557 skb_reset_network_header(skb); 1558 hdr = ipv6_hdr(skb); 1559 1560 ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel); 1561 hdr->hop_limit = np->cork.hop_limit; 1562 hdr->nexthdr = proto; 1563 hdr->saddr = fl6->saddr; 1564 hdr->daddr = *final_dst; 1565 1566 skb->priority = sk->sk_priority; 1567 skb->mark = sk->sk_mark; 1568 1569 skb_dst_set(skb, dst_clone(&rt->dst)); 1570 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1571 if (proto == IPPROTO_ICMPV6) { 1572 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1573 1574 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1575 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1576 } 1577 1578 err = ip6_local_out(skb); 1579 if (err) { 1580 if (err > 0) 1581 err = net_xmit_errno(err); 1582 if (err) 1583 goto error; 1584 } 1585 1586 out: 1587 ip6_cork_release(inet, np); 1588 return err; 1589 error: 1590 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1591 goto out; 1592 } 1593 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1594 1595 void ip6_flush_pending_frames(struct sock *sk) 1596 { 1597 struct sk_buff *skb; 1598 1599 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1600 if (skb_dst(skb)) 1601 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1602 IPSTATS_MIB_OUTDISCARDS); 1603 kfree_skb(skb); 1604 } 1605 1606 ip6_cork_release(inet_sk(sk), inet6_sk(sk)); 1607 } 1608 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1609