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, ip6_make_flowlabel(net, skb, fl6->flowlabel, 209 np->autoflowlabel)); 210 211 hdr->payload_len = htons(seg_len); 212 hdr->nexthdr = proto; 213 hdr->hop_limit = hlimit; 214 215 hdr->saddr = fl6->saddr; 216 hdr->daddr = *first_hop; 217 218 skb->protocol = htons(ETH_P_IPV6); 219 skb->priority = sk->sk_priority; 220 skb->mark = sk->sk_mark; 221 222 mtu = dst_mtu(dst); 223 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 224 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 225 IPSTATS_MIB_OUT, skb->len); 226 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 227 dst->dev, dst_output); 228 } 229 230 skb->dev = dst->dev; 231 ipv6_local_error(sk, EMSGSIZE, fl6, mtu); 232 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 233 kfree_skb(skb); 234 return -EMSGSIZE; 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 static void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt) 541 { 542 static u32 ip6_idents_hashrnd __read_mostly; 543 u32 hash, id; 544 545 net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd)); 546 547 hash = __ipv6_addr_jhash(&rt->rt6i_dst.addr, ip6_idents_hashrnd); 548 hash = __ipv6_addr_jhash(&rt->rt6i_src.addr, hash); 549 550 id = ip_idents_reserve(hash, 1); 551 fhdr->identification = htonl(id); 552 } 553 554 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 555 { 556 struct sk_buff *frag; 557 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 558 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 559 struct ipv6hdr *tmp_hdr; 560 struct frag_hdr *fh; 561 unsigned int mtu, hlen, left, len; 562 int hroom, troom; 563 __be32 frag_id = 0; 564 int ptr, offset = 0, err = 0; 565 u8 *prevhdr, nexthdr = 0; 566 struct net *net = dev_net(skb_dst(skb)->dev); 567 568 hlen = ip6_find_1stfragopt(skb, &prevhdr); 569 nexthdr = *prevhdr; 570 571 mtu = ip6_skb_dst_mtu(skb); 572 573 /* We must not fragment if the socket is set to force MTU discovery 574 * or if the skb it not generated by a local socket. 575 */ 576 if (unlikely(!skb->ignore_df && skb->len > mtu) || 577 (IP6CB(skb)->frag_max_size && 578 IP6CB(skb)->frag_max_size > mtu)) { 579 if (skb->sk && dst_allfrag(skb_dst(skb))) 580 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 581 582 skb->dev = skb_dst(skb)->dev; 583 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 584 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 585 IPSTATS_MIB_FRAGFAILS); 586 kfree_skb(skb); 587 return -EMSGSIZE; 588 } 589 590 if (np && np->frag_size < mtu) { 591 if (np->frag_size) 592 mtu = np->frag_size; 593 } 594 mtu -= hlen + sizeof(struct frag_hdr); 595 596 if (skb_has_frag_list(skb)) { 597 int first_len = skb_pagelen(skb); 598 struct sk_buff *frag2; 599 600 if (first_len - hlen > mtu || 601 ((first_len - hlen) & 7) || 602 skb_cloned(skb)) 603 goto slow_path; 604 605 skb_walk_frags(skb, frag) { 606 /* Correct geometry. */ 607 if (frag->len > mtu || 608 ((frag->len & 7) && frag->next) || 609 skb_headroom(frag) < hlen) 610 goto slow_path_clean; 611 612 /* Partially cloned skb? */ 613 if (skb_shared(frag)) 614 goto slow_path_clean; 615 616 BUG_ON(frag->sk); 617 if (skb->sk) { 618 frag->sk = skb->sk; 619 frag->destructor = sock_wfree; 620 } 621 skb->truesize -= frag->truesize; 622 } 623 624 err = 0; 625 offset = 0; 626 frag = skb_shinfo(skb)->frag_list; 627 skb_frag_list_init(skb); 628 /* BUILD HEADER */ 629 630 *prevhdr = NEXTHDR_FRAGMENT; 631 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 632 if (!tmp_hdr) { 633 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 634 IPSTATS_MIB_FRAGFAILS); 635 return -ENOMEM; 636 } 637 638 __skb_pull(skb, hlen); 639 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr)); 640 __skb_push(skb, hlen); 641 skb_reset_network_header(skb); 642 memcpy(skb_network_header(skb), tmp_hdr, hlen); 643 644 ipv6_select_ident(fh, rt); 645 fh->nexthdr = nexthdr; 646 fh->reserved = 0; 647 fh->frag_off = htons(IP6_MF); 648 frag_id = fh->identification; 649 650 first_len = skb_pagelen(skb); 651 skb->data_len = first_len - skb_headlen(skb); 652 skb->len = first_len; 653 ipv6_hdr(skb)->payload_len = htons(first_len - 654 sizeof(struct ipv6hdr)); 655 656 dst_hold(&rt->dst); 657 658 for (;;) { 659 /* Prepare header of the next frame, 660 * before previous one went down. */ 661 if (frag) { 662 frag->ip_summed = CHECKSUM_NONE; 663 skb_reset_transport_header(frag); 664 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr)); 665 __skb_push(frag, hlen); 666 skb_reset_network_header(frag); 667 memcpy(skb_network_header(frag), tmp_hdr, 668 hlen); 669 offset += skb->len - hlen - sizeof(struct frag_hdr); 670 fh->nexthdr = nexthdr; 671 fh->reserved = 0; 672 fh->frag_off = htons(offset); 673 if (frag->next != NULL) 674 fh->frag_off |= htons(IP6_MF); 675 fh->identification = frag_id; 676 ipv6_hdr(frag)->payload_len = 677 htons(frag->len - 678 sizeof(struct ipv6hdr)); 679 ip6_copy_metadata(frag, skb); 680 } 681 682 err = output(skb); 683 if (!err) 684 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 685 IPSTATS_MIB_FRAGCREATES); 686 687 if (err || !frag) 688 break; 689 690 skb = frag; 691 frag = skb->next; 692 skb->next = NULL; 693 } 694 695 kfree(tmp_hdr); 696 697 if (err == 0) { 698 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 699 IPSTATS_MIB_FRAGOKS); 700 ip6_rt_put(rt); 701 return 0; 702 } 703 704 kfree_skb_list(frag); 705 706 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 707 IPSTATS_MIB_FRAGFAILS); 708 ip6_rt_put(rt); 709 return err; 710 711 slow_path_clean: 712 skb_walk_frags(skb, frag2) { 713 if (frag2 == frag) 714 break; 715 frag2->sk = NULL; 716 frag2->destructor = NULL; 717 skb->truesize += frag2->truesize; 718 } 719 } 720 721 slow_path: 722 if ((skb->ip_summed == CHECKSUM_PARTIAL) && 723 skb_checksum_help(skb)) 724 goto fail; 725 726 left = skb->len - hlen; /* Space per frame */ 727 ptr = hlen; /* Where to start from */ 728 729 /* 730 * Fragment the datagram. 731 */ 732 733 *prevhdr = NEXTHDR_FRAGMENT; 734 hroom = LL_RESERVED_SPACE(rt->dst.dev); 735 troom = rt->dst.dev->needed_tailroom; 736 737 /* 738 * Keep copying data until we run out. 739 */ 740 while (left > 0) { 741 len = left; 742 /* IF: it doesn't fit, use 'mtu' - the data space left */ 743 if (len > mtu) 744 len = mtu; 745 /* IF: we are not sending up to and including the packet end 746 then align the next start on an eight byte boundary */ 747 if (len < left) { 748 len &= ~7; 749 } 750 751 /* Allocate buffer */ 752 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 753 hroom + troom, GFP_ATOMIC); 754 if (!frag) { 755 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 756 IPSTATS_MIB_FRAGFAILS); 757 err = -ENOMEM; 758 goto fail; 759 } 760 761 /* 762 * Set up data on packet 763 */ 764 765 ip6_copy_metadata(frag, skb); 766 skb_reserve(frag, hroom); 767 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 768 skb_reset_network_header(frag); 769 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 770 frag->transport_header = (frag->network_header + hlen + 771 sizeof(struct frag_hdr)); 772 773 /* 774 * Charge the memory for the fragment to any owner 775 * it might possess 776 */ 777 if (skb->sk) 778 skb_set_owner_w(frag, skb->sk); 779 780 /* 781 * Copy the packet header into the new buffer. 782 */ 783 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 784 785 /* 786 * Build fragment header. 787 */ 788 fh->nexthdr = nexthdr; 789 fh->reserved = 0; 790 if (!frag_id) { 791 ipv6_select_ident(fh, rt); 792 frag_id = fh->identification; 793 } else 794 fh->identification = frag_id; 795 796 /* 797 * Copy a block of the IP datagram. 798 */ 799 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag), 800 len)); 801 left -= len; 802 803 fh->frag_off = htons(offset); 804 if (left > 0) 805 fh->frag_off |= htons(IP6_MF); 806 ipv6_hdr(frag)->payload_len = htons(frag->len - 807 sizeof(struct ipv6hdr)); 808 809 ptr += len; 810 offset += len; 811 812 /* 813 * Put this fragment into the sending queue. 814 */ 815 err = output(frag); 816 if (err) 817 goto fail; 818 819 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 820 IPSTATS_MIB_FRAGCREATES); 821 } 822 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 823 IPSTATS_MIB_FRAGOKS); 824 consume_skb(skb); 825 return err; 826 827 fail: 828 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 829 IPSTATS_MIB_FRAGFAILS); 830 kfree_skb(skb); 831 return err; 832 } 833 834 static inline int ip6_rt_check(const struct rt6key *rt_key, 835 const struct in6_addr *fl_addr, 836 const struct in6_addr *addr_cache) 837 { 838 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 839 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)); 840 } 841 842 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 843 struct dst_entry *dst, 844 const struct flowi6 *fl6) 845 { 846 struct ipv6_pinfo *np = inet6_sk(sk); 847 struct rt6_info *rt; 848 849 if (!dst) 850 goto out; 851 852 if (dst->ops->family != AF_INET6) { 853 dst_release(dst); 854 return NULL; 855 } 856 857 rt = (struct rt6_info *)dst; 858 /* Yes, checking route validity in not connected 859 * case is not very simple. Take into account, 860 * that we do not support routing by source, TOS, 861 * and MSG_DONTROUTE --ANK (980726) 862 * 863 * 1. ip6_rt_check(): If route was host route, 864 * check that cached destination is current. 865 * If it is network route, we still may 866 * check its validity using saved pointer 867 * to the last used address: daddr_cache. 868 * We do not want to save whole address now, 869 * (because main consumer of this service 870 * is tcp, which has not this problem), 871 * so that the last trick works only on connected 872 * sockets. 873 * 2. oif also should be the same. 874 */ 875 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 876 #ifdef CONFIG_IPV6_SUBTREES 877 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 878 #endif 879 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 880 dst_release(dst); 881 dst = NULL; 882 } 883 884 out: 885 return dst; 886 } 887 888 static int ip6_dst_lookup_tail(struct sock *sk, 889 struct dst_entry **dst, struct flowi6 *fl6) 890 { 891 struct net *net = sock_net(sk); 892 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 893 struct neighbour *n; 894 struct rt6_info *rt; 895 #endif 896 int err; 897 898 if (*dst == NULL) 899 *dst = ip6_route_output(net, sk, fl6); 900 901 err = (*dst)->error; 902 if (err) 903 goto out_err_release; 904 905 if (ipv6_addr_any(&fl6->saddr)) { 906 struct rt6_info *rt = (struct rt6_info *) *dst; 907 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 908 sk ? inet6_sk(sk)->srcprefs : 0, 909 &fl6->saddr); 910 if (err) 911 goto out_err_release; 912 } 913 914 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 915 /* 916 * Here if the dst entry we've looked up 917 * has a neighbour entry that is in the INCOMPLETE 918 * state and the src address from the flow is 919 * marked as OPTIMISTIC, we release the found 920 * dst entry and replace it instead with the 921 * dst entry of the nexthop router 922 */ 923 rt = (struct rt6_info *) *dst; 924 rcu_read_lock_bh(); 925 n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt)); 926 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 927 rcu_read_unlock_bh(); 928 929 if (err) { 930 struct inet6_ifaddr *ifp; 931 struct flowi6 fl_gw6; 932 int redirect; 933 934 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 935 (*dst)->dev, 1); 936 937 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 938 if (ifp) 939 in6_ifa_put(ifp); 940 941 if (redirect) { 942 /* 943 * We need to get the dst entry for the 944 * default router instead 945 */ 946 dst_release(*dst); 947 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 948 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 949 *dst = ip6_route_output(net, sk, &fl_gw6); 950 err = (*dst)->error; 951 if (err) 952 goto out_err_release; 953 } 954 } 955 #endif 956 957 return 0; 958 959 out_err_release: 960 if (err == -ENETUNREACH) 961 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 962 dst_release(*dst); 963 *dst = NULL; 964 return err; 965 } 966 967 /** 968 * ip6_dst_lookup - perform route lookup on flow 969 * @sk: socket which provides route info 970 * @dst: pointer to dst_entry * for result 971 * @fl6: flow to lookup 972 * 973 * This function performs a route lookup on the given flow. 974 * 975 * It returns zero on success, or a standard errno code on error. 976 */ 977 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6) 978 { 979 *dst = NULL; 980 return ip6_dst_lookup_tail(sk, dst, fl6); 981 } 982 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 983 984 /** 985 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 986 * @sk: socket which provides route info 987 * @fl6: flow to lookup 988 * @final_dst: final destination address for ipsec lookup 989 * 990 * This function performs a route lookup on the given flow. 991 * 992 * It returns a valid dst pointer on success, or a pointer encoded 993 * error code. 994 */ 995 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 996 const struct in6_addr *final_dst) 997 { 998 struct dst_entry *dst = NULL; 999 int err; 1000 1001 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1002 if (err) 1003 return ERR_PTR(err); 1004 if (final_dst) 1005 fl6->daddr = *final_dst; 1006 1007 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1008 } 1009 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1010 1011 /** 1012 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1013 * @sk: socket which provides the dst cache and route info 1014 * @fl6: flow to lookup 1015 * @final_dst: final destination address for ipsec lookup 1016 * 1017 * This function performs a route lookup on the given flow with the 1018 * possibility of using the cached route in the socket if it is valid. 1019 * It will take the socket dst lock when operating on the dst cache. 1020 * As a result, this function can only be used in process context. 1021 * 1022 * It returns a valid dst pointer on success, or a pointer encoded 1023 * error code. 1024 */ 1025 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1026 const struct in6_addr *final_dst) 1027 { 1028 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1029 int err; 1030 1031 dst = ip6_sk_dst_check(sk, dst, fl6); 1032 1033 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1034 if (err) 1035 return ERR_PTR(err); 1036 if (final_dst) 1037 fl6->daddr = *final_dst; 1038 1039 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1040 } 1041 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1042 1043 static inline int ip6_ufo_append_data(struct sock *sk, 1044 int getfrag(void *from, char *to, int offset, int len, 1045 int odd, struct sk_buff *skb), 1046 void *from, int length, int hh_len, int fragheaderlen, 1047 int transhdrlen, int mtu, unsigned int flags, 1048 struct rt6_info *rt) 1049 1050 { 1051 struct sk_buff *skb; 1052 struct frag_hdr fhdr; 1053 int err; 1054 1055 /* There is support for UDP large send offload by network 1056 * device, so create one single skb packet containing complete 1057 * udp datagram 1058 */ 1059 skb = skb_peek_tail(&sk->sk_write_queue); 1060 if (skb == NULL) { 1061 skb = sock_alloc_send_skb(sk, 1062 hh_len + fragheaderlen + transhdrlen + 20, 1063 (flags & MSG_DONTWAIT), &err); 1064 if (skb == NULL) 1065 return err; 1066 1067 /* reserve space for Hardware header */ 1068 skb_reserve(skb, hh_len); 1069 1070 /* create space for UDP/IP header */ 1071 skb_put(skb, fragheaderlen + transhdrlen); 1072 1073 /* initialize network header pointer */ 1074 skb_reset_network_header(skb); 1075 1076 /* initialize protocol header pointer */ 1077 skb->transport_header = skb->network_header + fragheaderlen; 1078 1079 skb->protocol = htons(ETH_P_IPV6); 1080 skb->csum = 0; 1081 1082 __skb_queue_tail(&sk->sk_write_queue, skb); 1083 } else if (skb_is_gso(skb)) { 1084 goto append; 1085 } 1086 1087 skb->ip_summed = CHECKSUM_PARTIAL; 1088 /* Specify the length of each IPv6 datagram fragment. 1089 * It has to be a multiple of 8. 1090 */ 1091 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1092 sizeof(struct frag_hdr)) & ~7; 1093 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1094 ipv6_select_ident(&fhdr, rt); 1095 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 1096 1097 append: 1098 return skb_append_datato_frags(sk, skb, getfrag, from, 1099 (length - transhdrlen)); 1100 } 1101 1102 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1103 gfp_t gfp) 1104 { 1105 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1106 } 1107 1108 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1109 gfp_t gfp) 1110 { 1111 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1112 } 1113 1114 static void ip6_append_data_mtu(unsigned int *mtu, 1115 int *maxfraglen, 1116 unsigned int fragheaderlen, 1117 struct sk_buff *skb, 1118 struct rt6_info *rt, 1119 unsigned int orig_mtu) 1120 { 1121 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1122 if (skb == NULL) { 1123 /* first fragment, reserve header_len */ 1124 *mtu = orig_mtu - rt->dst.header_len; 1125 1126 } else { 1127 /* 1128 * this fragment is not first, the headers 1129 * space is regarded as data space. 1130 */ 1131 *mtu = orig_mtu; 1132 } 1133 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1134 + fragheaderlen - sizeof(struct frag_hdr); 1135 } 1136 } 1137 1138 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1139 struct inet6_cork *v6_cork, 1140 int hlimit, int tclass, struct ipv6_txoptions *opt, 1141 struct rt6_info *rt, struct flowi6 *fl6) 1142 { 1143 struct ipv6_pinfo *np = inet6_sk(sk); 1144 unsigned int mtu; 1145 1146 /* 1147 * setup for corking 1148 */ 1149 if (opt) { 1150 if (WARN_ON(v6_cork->opt)) 1151 return -EINVAL; 1152 1153 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation); 1154 if (unlikely(v6_cork->opt == NULL)) 1155 return -ENOBUFS; 1156 1157 v6_cork->opt->tot_len = opt->tot_len; 1158 v6_cork->opt->opt_flen = opt->opt_flen; 1159 v6_cork->opt->opt_nflen = opt->opt_nflen; 1160 1161 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1162 sk->sk_allocation); 1163 if (opt->dst0opt && !v6_cork->opt->dst0opt) 1164 return -ENOBUFS; 1165 1166 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1167 sk->sk_allocation); 1168 if (opt->dst1opt && !v6_cork->opt->dst1opt) 1169 return -ENOBUFS; 1170 1171 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt, 1172 sk->sk_allocation); 1173 if (opt->hopopt && !v6_cork->opt->hopopt) 1174 return -ENOBUFS; 1175 1176 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1177 sk->sk_allocation); 1178 if (opt->srcrt && !v6_cork->opt->srcrt) 1179 return -ENOBUFS; 1180 1181 /* need source address above miyazawa*/ 1182 } 1183 dst_hold(&rt->dst); 1184 cork->base.dst = &rt->dst; 1185 cork->fl.u.ip6 = *fl6; 1186 v6_cork->hop_limit = hlimit; 1187 v6_cork->tclass = tclass; 1188 if (rt->dst.flags & DST_XFRM_TUNNEL) 1189 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1190 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1191 else 1192 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1193 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1194 if (np->frag_size < mtu) { 1195 if (np->frag_size) 1196 mtu = np->frag_size; 1197 } 1198 cork->base.fragsize = mtu; 1199 if (dst_allfrag(rt->dst.path)) 1200 cork->base.flags |= IPCORK_ALLFRAG; 1201 cork->base.length = 0; 1202 1203 return 0; 1204 } 1205 1206 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 1207 int offset, int len, int odd, struct sk_buff *skb), 1208 void *from, int length, int transhdrlen, 1209 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1210 struct rt6_info *rt, unsigned int flags, int dontfrag) 1211 { 1212 struct inet_sock *inet = inet_sk(sk); 1213 struct ipv6_pinfo *np = inet6_sk(sk); 1214 struct inet_cork *cork; 1215 struct sk_buff *skb, *skb_prev = NULL; 1216 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1217 int exthdrlen; 1218 int dst_exthdrlen; 1219 int hh_len; 1220 int copy; 1221 int err; 1222 int offset = 0; 1223 __u8 tx_flags = 0; 1224 u32 tskey = 0; 1225 1226 if (flags&MSG_PROBE) 1227 return 0; 1228 cork = &inet->cork.base; 1229 if (skb_queue_empty(&sk->sk_write_queue)) { 1230 /* 1231 * setup for corking 1232 */ 1233 err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit, 1234 tclass, opt, rt, fl6); 1235 if (err) 1236 return err; 1237 exthdrlen = (opt ? opt->opt_flen : 0); 1238 length += exthdrlen; 1239 transhdrlen += exthdrlen; 1240 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1241 } else { 1242 rt = (struct rt6_info *)cork->dst; 1243 fl6 = &inet->cork.fl.u.ip6; 1244 opt = np->cork.opt; 1245 transhdrlen = 0; 1246 exthdrlen = 0; 1247 dst_exthdrlen = 0; 1248 } 1249 mtu = cork->fragsize; 1250 orig_mtu = mtu; 1251 1252 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1253 1254 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1255 (opt ? opt->opt_nflen : 0); 1256 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1257 sizeof(struct frag_hdr); 1258 1259 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1260 unsigned int maxnonfragsize, headersize; 1261 1262 headersize = sizeof(struct ipv6hdr) + 1263 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1264 (dst_allfrag(&rt->dst) ? 1265 sizeof(struct frag_hdr) : 0) + 1266 rt->rt6i_nfheader_len; 1267 1268 if (ip6_sk_ignore_df(sk)) 1269 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1270 else 1271 maxnonfragsize = mtu; 1272 1273 /* dontfrag active */ 1274 if ((cork->length + length > mtu - headersize) && dontfrag && 1275 (sk->sk_protocol == IPPROTO_UDP || 1276 sk->sk_protocol == IPPROTO_RAW)) { 1277 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1278 sizeof(struct ipv6hdr)); 1279 goto emsgsize; 1280 } 1281 1282 if (cork->length + length > maxnonfragsize - headersize) { 1283 emsgsize: 1284 ipv6_local_error(sk, EMSGSIZE, fl6, 1285 mtu - headersize + 1286 sizeof(struct ipv6hdr)); 1287 return -EMSGSIZE; 1288 } 1289 } 1290 1291 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1292 sock_tx_timestamp(sk, &tx_flags); 1293 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1294 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1295 tskey = sk->sk_tskey++; 1296 } 1297 1298 /* 1299 * Let's try using as much space as possible. 1300 * Use MTU if total length of the message fits into the MTU. 1301 * Otherwise, we need to reserve fragment header and 1302 * fragment alignment (= 8-15 octects, in total). 1303 * 1304 * Note that we may need to "move" the data from the tail of 1305 * of the buffer to the new fragment when we split 1306 * the message. 1307 * 1308 * FIXME: It may be fragmented into multiple chunks 1309 * at once if non-fragmentable extension headers 1310 * are too large. 1311 * --yoshfuji 1312 */ 1313 1314 skb = skb_peek_tail(&sk->sk_write_queue); 1315 cork->length += length; 1316 if (((length > mtu) || 1317 (skb && skb_is_gso(skb))) && 1318 (sk->sk_protocol == IPPROTO_UDP) && 1319 (rt->dst.dev->features & NETIF_F_UFO)) { 1320 err = ip6_ufo_append_data(sk, getfrag, from, length, 1321 hh_len, fragheaderlen, 1322 transhdrlen, mtu, flags, rt); 1323 if (err) 1324 goto error; 1325 return 0; 1326 } 1327 1328 if (!skb) 1329 goto alloc_new_skb; 1330 1331 while (length > 0) { 1332 /* Check if the remaining data fits into current packet. */ 1333 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1334 if (copy < length) 1335 copy = maxfraglen - skb->len; 1336 1337 if (copy <= 0) { 1338 char *data; 1339 unsigned int datalen; 1340 unsigned int fraglen; 1341 unsigned int fraggap; 1342 unsigned int alloclen; 1343 alloc_new_skb: 1344 /* There's no room in the current skb */ 1345 if (skb) 1346 fraggap = skb->len - maxfraglen; 1347 else 1348 fraggap = 0; 1349 /* update mtu and maxfraglen if necessary */ 1350 if (skb == NULL || skb_prev == NULL) 1351 ip6_append_data_mtu(&mtu, &maxfraglen, 1352 fragheaderlen, skb, rt, 1353 orig_mtu); 1354 1355 skb_prev = skb; 1356 1357 /* 1358 * If remaining data exceeds the mtu, 1359 * we know we need more fragment(s). 1360 */ 1361 datalen = length + fraggap; 1362 1363 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1364 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1365 if ((flags & MSG_MORE) && 1366 !(rt->dst.dev->features&NETIF_F_SG)) 1367 alloclen = mtu; 1368 else 1369 alloclen = datalen + fragheaderlen; 1370 1371 alloclen += dst_exthdrlen; 1372 1373 if (datalen != length + fraggap) { 1374 /* 1375 * this is not the last fragment, the trailer 1376 * space is regarded as data space. 1377 */ 1378 datalen += rt->dst.trailer_len; 1379 } 1380 1381 alloclen += rt->dst.trailer_len; 1382 fraglen = datalen + fragheaderlen; 1383 1384 /* 1385 * We just reserve space for fragment header. 1386 * Note: this may be overallocation if the message 1387 * (without MSG_MORE) fits into the MTU. 1388 */ 1389 alloclen += sizeof(struct frag_hdr); 1390 1391 if (transhdrlen) { 1392 skb = sock_alloc_send_skb(sk, 1393 alloclen + hh_len, 1394 (flags & MSG_DONTWAIT), &err); 1395 } else { 1396 skb = NULL; 1397 if (atomic_read(&sk->sk_wmem_alloc) <= 1398 2 * sk->sk_sndbuf) 1399 skb = sock_wmalloc(sk, 1400 alloclen + hh_len, 1, 1401 sk->sk_allocation); 1402 if (unlikely(skb == NULL)) 1403 err = -ENOBUFS; 1404 } 1405 if (skb == NULL) 1406 goto error; 1407 /* 1408 * Fill in the control structures 1409 */ 1410 skb->protocol = htons(ETH_P_IPV6); 1411 skb->ip_summed = CHECKSUM_NONE; 1412 skb->csum = 0; 1413 /* reserve for fragmentation and ipsec header */ 1414 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1415 dst_exthdrlen); 1416 1417 /* Only the initial fragment is time stamped */ 1418 skb_shinfo(skb)->tx_flags = tx_flags; 1419 tx_flags = 0; 1420 skb_shinfo(skb)->tskey = tskey; 1421 tskey = 0; 1422 1423 /* 1424 * Find where to start putting bytes 1425 */ 1426 data = skb_put(skb, fraglen); 1427 skb_set_network_header(skb, exthdrlen); 1428 data += fragheaderlen; 1429 skb->transport_header = (skb->network_header + 1430 fragheaderlen); 1431 if (fraggap) { 1432 skb->csum = skb_copy_and_csum_bits( 1433 skb_prev, maxfraglen, 1434 data + transhdrlen, fraggap, 0); 1435 skb_prev->csum = csum_sub(skb_prev->csum, 1436 skb->csum); 1437 data += fraggap; 1438 pskb_trim_unique(skb_prev, maxfraglen); 1439 } 1440 copy = datalen - transhdrlen - fraggap; 1441 1442 if (copy < 0) { 1443 err = -EINVAL; 1444 kfree_skb(skb); 1445 goto error; 1446 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1447 err = -EFAULT; 1448 kfree_skb(skb); 1449 goto error; 1450 } 1451 1452 offset += copy; 1453 length -= datalen - fraggap; 1454 transhdrlen = 0; 1455 exthdrlen = 0; 1456 dst_exthdrlen = 0; 1457 1458 /* 1459 * Put the packet on the pending queue 1460 */ 1461 __skb_queue_tail(&sk->sk_write_queue, skb); 1462 continue; 1463 } 1464 1465 if (copy > length) 1466 copy = length; 1467 1468 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1469 unsigned int off; 1470 1471 off = skb->len; 1472 if (getfrag(from, skb_put(skb, copy), 1473 offset, copy, off, skb) < 0) { 1474 __skb_trim(skb, off); 1475 err = -EFAULT; 1476 goto error; 1477 } 1478 } else { 1479 int i = skb_shinfo(skb)->nr_frags; 1480 struct page_frag *pfrag = sk_page_frag(sk); 1481 1482 err = -ENOMEM; 1483 if (!sk_page_frag_refill(sk, pfrag)) 1484 goto error; 1485 1486 if (!skb_can_coalesce(skb, i, pfrag->page, 1487 pfrag->offset)) { 1488 err = -EMSGSIZE; 1489 if (i == MAX_SKB_FRAGS) 1490 goto error; 1491 1492 __skb_fill_page_desc(skb, i, pfrag->page, 1493 pfrag->offset, 0); 1494 skb_shinfo(skb)->nr_frags = ++i; 1495 get_page(pfrag->page); 1496 } 1497 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1498 if (getfrag(from, 1499 page_address(pfrag->page) + pfrag->offset, 1500 offset, copy, skb->len, skb) < 0) 1501 goto error_efault; 1502 1503 pfrag->offset += copy; 1504 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1505 skb->len += copy; 1506 skb->data_len += copy; 1507 skb->truesize += copy; 1508 atomic_add(copy, &sk->sk_wmem_alloc); 1509 } 1510 offset += copy; 1511 length -= copy; 1512 } 1513 1514 return 0; 1515 1516 error_efault: 1517 err = -EFAULT; 1518 error: 1519 cork->length -= length; 1520 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1521 return err; 1522 } 1523 EXPORT_SYMBOL_GPL(ip6_append_data); 1524 1525 static void ip6_cork_release(struct inet_cork_full *cork, 1526 struct inet6_cork *v6_cork) 1527 { 1528 if (v6_cork->opt) { 1529 kfree(v6_cork->opt->dst0opt); 1530 kfree(v6_cork->opt->dst1opt); 1531 kfree(v6_cork->opt->hopopt); 1532 kfree(v6_cork->opt->srcrt); 1533 kfree(v6_cork->opt); 1534 v6_cork->opt = NULL; 1535 } 1536 1537 if (cork->base.dst) { 1538 dst_release(cork->base.dst); 1539 cork->base.dst = NULL; 1540 cork->base.flags &= ~IPCORK_ALLFRAG; 1541 } 1542 memset(&cork->fl, 0, sizeof(cork->fl)); 1543 } 1544 1545 int ip6_push_pending_frames(struct sock *sk) 1546 { 1547 struct sk_buff *skb, *tmp_skb; 1548 struct sk_buff **tail_skb; 1549 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1550 struct inet_sock *inet = inet_sk(sk); 1551 struct ipv6_pinfo *np = inet6_sk(sk); 1552 struct net *net = sock_net(sk); 1553 struct ipv6hdr *hdr; 1554 struct ipv6_txoptions *opt = np->cork.opt; 1555 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst; 1556 struct flowi6 *fl6 = &inet->cork.fl.u.ip6; 1557 unsigned char proto = fl6->flowi6_proto; 1558 int err = 0; 1559 1560 skb = __skb_dequeue(&sk->sk_write_queue); 1561 if (skb == NULL) 1562 goto out; 1563 tail_skb = &(skb_shinfo(skb)->frag_list); 1564 1565 /* move skb->data to ip header from ext header */ 1566 if (skb->data < skb_network_header(skb)) 1567 __skb_pull(skb, skb_network_offset(skb)); 1568 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1569 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1570 *tail_skb = tmp_skb; 1571 tail_skb = &(tmp_skb->next); 1572 skb->len += tmp_skb->len; 1573 skb->data_len += tmp_skb->len; 1574 skb->truesize += tmp_skb->truesize; 1575 tmp_skb->destructor = NULL; 1576 tmp_skb->sk = NULL; 1577 } 1578 1579 /* Allow local fragmentation. */ 1580 skb->ignore_df = ip6_sk_ignore_df(sk); 1581 1582 *final_dst = fl6->daddr; 1583 __skb_pull(skb, skb_network_header_len(skb)); 1584 if (opt && opt->opt_flen) 1585 ipv6_push_frag_opts(skb, opt, &proto); 1586 if (opt && opt->opt_nflen) 1587 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1588 1589 skb_push(skb, sizeof(struct ipv6hdr)); 1590 skb_reset_network_header(skb); 1591 hdr = ipv6_hdr(skb); 1592 1593 ip6_flow_hdr(hdr, np->cork.tclass, 1594 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1595 np->autoflowlabel)); 1596 hdr->hop_limit = np->cork.hop_limit; 1597 hdr->nexthdr = proto; 1598 hdr->saddr = fl6->saddr; 1599 hdr->daddr = *final_dst; 1600 1601 skb->priority = sk->sk_priority; 1602 skb->mark = sk->sk_mark; 1603 1604 skb_dst_set(skb, dst_clone(&rt->dst)); 1605 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1606 if (proto == IPPROTO_ICMPV6) { 1607 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1608 1609 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1610 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1611 } 1612 1613 err = ip6_local_out(skb); 1614 if (err) { 1615 if (err > 0) 1616 err = net_xmit_errno(err); 1617 if (err) 1618 goto error; 1619 } 1620 1621 out: 1622 ip6_cork_release(&inet->cork, &np->cork); 1623 return err; 1624 error: 1625 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1626 goto out; 1627 } 1628 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1629 1630 void ip6_flush_pending_frames(struct sock *sk) 1631 { 1632 struct sk_buff *skb; 1633 1634 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1635 if (skb_dst(skb)) 1636 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1637 IPSTATS_MIB_OUTDISCARDS); 1638 kfree_skb(skb); 1639 } 1640 1641 ip6_cork_release(&inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1642 } 1643 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1644