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 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 1139 int offset, int len, int odd, struct sk_buff *skb), 1140 void *from, int length, int transhdrlen, 1141 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1142 struct rt6_info *rt, unsigned int flags, int dontfrag) 1143 { 1144 struct inet_sock *inet = inet_sk(sk); 1145 struct ipv6_pinfo *np = inet6_sk(sk); 1146 struct inet_cork *cork; 1147 struct sk_buff *skb, *skb_prev = NULL; 1148 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1149 int exthdrlen; 1150 int dst_exthdrlen; 1151 int hh_len; 1152 int copy; 1153 int err; 1154 int offset = 0; 1155 __u8 tx_flags = 0; 1156 u32 tskey = 0; 1157 1158 if (flags&MSG_PROBE) 1159 return 0; 1160 cork = &inet->cork.base; 1161 if (skb_queue_empty(&sk->sk_write_queue)) { 1162 /* 1163 * setup for corking 1164 */ 1165 if (opt) { 1166 if (WARN_ON(np->cork.opt)) 1167 return -EINVAL; 1168 1169 np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation); 1170 if (unlikely(np->cork.opt == NULL)) 1171 return -ENOBUFS; 1172 1173 np->cork.opt->tot_len = opt->tot_len; 1174 np->cork.opt->opt_flen = opt->opt_flen; 1175 np->cork.opt->opt_nflen = opt->opt_nflen; 1176 1177 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1178 sk->sk_allocation); 1179 if (opt->dst0opt && !np->cork.opt->dst0opt) 1180 return -ENOBUFS; 1181 1182 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1183 sk->sk_allocation); 1184 if (opt->dst1opt && !np->cork.opt->dst1opt) 1185 return -ENOBUFS; 1186 1187 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt, 1188 sk->sk_allocation); 1189 if (opt->hopopt && !np->cork.opt->hopopt) 1190 return -ENOBUFS; 1191 1192 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1193 sk->sk_allocation); 1194 if (opt->srcrt && !np->cork.opt->srcrt) 1195 return -ENOBUFS; 1196 1197 /* need source address above miyazawa*/ 1198 } 1199 dst_hold(&rt->dst); 1200 cork->dst = &rt->dst; 1201 inet->cork.fl.u.ip6 = *fl6; 1202 np->cork.hop_limit = hlimit; 1203 np->cork.tclass = tclass; 1204 if (rt->dst.flags & DST_XFRM_TUNNEL) 1205 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1206 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1207 else 1208 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1209 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1210 if (np->frag_size < mtu) { 1211 if (np->frag_size) 1212 mtu = np->frag_size; 1213 } 1214 cork->fragsize = mtu; 1215 if (dst_allfrag(rt->dst.path)) 1216 cork->flags |= IPCORK_ALLFRAG; 1217 cork->length = 0; 1218 exthdrlen = (opt ? opt->opt_flen : 0); 1219 length += exthdrlen; 1220 transhdrlen += exthdrlen; 1221 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1222 } else { 1223 rt = (struct rt6_info *)cork->dst; 1224 fl6 = &inet->cork.fl.u.ip6; 1225 opt = np->cork.opt; 1226 transhdrlen = 0; 1227 exthdrlen = 0; 1228 dst_exthdrlen = 0; 1229 mtu = cork->fragsize; 1230 } 1231 orig_mtu = mtu; 1232 1233 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1234 1235 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1236 (opt ? opt->opt_nflen : 0); 1237 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1238 sizeof(struct frag_hdr); 1239 1240 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1241 unsigned int maxnonfragsize, headersize; 1242 1243 headersize = sizeof(struct ipv6hdr) + 1244 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1245 (dst_allfrag(&rt->dst) ? 1246 sizeof(struct frag_hdr) : 0) + 1247 rt->rt6i_nfheader_len; 1248 1249 if (ip6_sk_ignore_df(sk)) 1250 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1251 else 1252 maxnonfragsize = mtu; 1253 1254 /* dontfrag active */ 1255 if ((cork->length + length > mtu - headersize) && dontfrag && 1256 (sk->sk_protocol == IPPROTO_UDP || 1257 sk->sk_protocol == IPPROTO_RAW)) { 1258 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1259 sizeof(struct ipv6hdr)); 1260 goto emsgsize; 1261 } 1262 1263 if (cork->length + length > maxnonfragsize - headersize) { 1264 emsgsize: 1265 ipv6_local_error(sk, EMSGSIZE, fl6, 1266 mtu - headersize + 1267 sizeof(struct ipv6hdr)); 1268 return -EMSGSIZE; 1269 } 1270 } 1271 1272 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1273 sock_tx_timestamp(sk, &tx_flags); 1274 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1275 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1276 tskey = sk->sk_tskey++; 1277 } 1278 1279 /* 1280 * Let's try using as much space as possible. 1281 * Use MTU if total length of the message fits into the MTU. 1282 * Otherwise, we need to reserve fragment header and 1283 * fragment alignment (= 8-15 octects, in total). 1284 * 1285 * Note that we may need to "move" the data from the tail of 1286 * of the buffer to the new fragment when we split 1287 * the message. 1288 * 1289 * FIXME: It may be fragmented into multiple chunks 1290 * at once if non-fragmentable extension headers 1291 * are too large. 1292 * --yoshfuji 1293 */ 1294 1295 skb = skb_peek_tail(&sk->sk_write_queue); 1296 cork->length += length; 1297 if (((length > mtu) || 1298 (skb && skb_is_gso(skb))) && 1299 (sk->sk_protocol == IPPROTO_UDP) && 1300 (rt->dst.dev->features & NETIF_F_UFO)) { 1301 err = ip6_ufo_append_data(sk, getfrag, from, length, 1302 hh_len, fragheaderlen, 1303 transhdrlen, mtu, flags, rt); 1304 if (err) 1305 goto error; 1306 return 0; 1307 } 1308 1309 if (!skb) 1310 goto alloc_new_skb; 1311 1312 while (length > 0) { 1313 /* Check if the remaining data fits into current packet. */ 1314 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1315 if (copy < length) 1316 copy = maxfraglen - skb->len; 1317 1318 if (copy <= 0) { 1319 char *data; 1320 unsigned int datalen; 1321 unsigned int fraglen; 1322 unsigned int fraggap; 1323 unsigned int alloclen; 1324 alloc_new_skb: 1325 /* There's no room in the current skb */ 1326 if (skb) 1327 fraggap = skb->len - maxfraglen; 1328 else 1329 fraggap = 0; 1330 /* update mtu and maxfraglen if necessary */ 1331 if (skb == NULL || skb_prev == NULL) 1332 ip6_append_data_mtu(&mtu, &maxfraglen, 1333 fragheaderlen, skb, rt, 1334 orig_mtu); 1335 1336 skb_prev = skb; 1337 1338 /* 1339 * If remaining data exceeds the mtu, 1340 * we know we need more fragment(s). 1341 */ 1342 datalen = length + fraggap; 1343 1344 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1345 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1346 if ((flags & MSG_MORE) && 1347 !(rt->dst.dev->features&NETIF_F_SG)) 1348 alloclen = mtu; 1349 else 1350 alloclen = datalen + fragheaderlen; 1351 1352 alloclen += dst_exthdrlen; 1353 1354 if (datalen != length + fraggap) { 1355 /* 1356 * this is not the last fragment, the trailer 1357 * space is regarded as data space. 1358 */ 1359 datalen += rt->dst.trailer_len; 1360 } 1361 1362 alloclen += rt->dst.trailer_len; 1363 fraglen = datalen + fragheaderlen; 1364 1365 /* 1366 * We just reserve space for fragment header. 1367 * Note: this may be overallocation if the message 1368 * (without MSG_MORE) fits into the MTU. 1369 */ 1370 alloclen += sizeof(struct frag_hdr); 1371 1372 if (transhdrlen) { 1373 skb = sock_alloc_send_skb(sk, 1374 alloclen + hh_len, 1375 (flags & MSG_DONTWAIT), &err); 1376 } else { 1377 skb = NULL; 1378 if (atomic_read(&sk->sk_wmem_alloc) <= 1379 2 * sk->sk_sndbuf) 1380 skb = sock_wmalloc(sk, 1381 alloclen + hh_len, 1, 1382 sk->sk_allocation); 1383 if (unlikely(skb == NULL)) 1384 err = -ENOBUFS; 1385 } 1386 if (skb == NULL) 1387 goto error; 1388 /* 1389 * Fill in the control structures 1390 */ 1391 skb->protocol = htons(ETH_P_IPV6); 1392 skb->ip_summed = CHECKSUM_NONE; 1393 skb->csum = 0; 1394 /* reserve for fragmentation and ipsec header */ 1395 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1396 dst_exthdrlen); 1397 1398 /* Only the initial fragment is time stamped */ 1399 skb_shinfo(skb)->tx_flags = tx_flags; 1400 tx_flags = 0; 1401 skb_shinfo(skb)->tskey = tskey; 1402 tskey = 0; 1403 1404 /* 1405 * Find where to start putting bytes 1406 */ 1407 data = skb_put(skb, fraglen); 1408 skb_set_network_header(skb, exthdrlen); 1409 data += fragheaderlen; 1410 skb->transport_header = (skb->network_header + 1411 fragheaderlen); 1412 if (fraggap) { 1413 skb->csum = skb_copy_and_csum_bits( 1414 skb_prev, maxfraglen, 1415 data + transhdrlen, fraggap, 0); 1416 skb_prev->csum = csum_sub(skb_prev->csum, 1417 skb->csum); 1418 data += fraggap; 1419 pskb_trim_unique(skb_prev, maxfraglen); 1420 } 1421 copy = datalen - transhdrlen - fraggap; 1422 1423 if (copy < 0) { 1424 err = -EINVAL; 1425 kfree_skb(skb); 1426 goto error; 1427 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1428 err = -EFAULT; 1429 kfree_skb(skb); 1430 goto error; 1431 } 1432 1433 offset += copy; 1434 length -= datalen - fraggap; 1435 transhdrlen = 0; 1436 exthdrlen = 0; 1437 dst_exthdrlen = 0; 1438 1439 /* 1440 * Put the packet on the pending queue 1441 */ 1442 __skb_queue_tail(&sk->sk_write_queue, skb); 1443 continue; 1444 } 1445 1446 if (copy > length) 1447 copy = length; 1448 1449 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1450 unsigned int off; 1451 1452 off = skb->len; 1453 if (getfrag(from, skb_put(skb, copy), 1454 offset, copy, off, skb) < 0) { 1455 __skb_trim(skb, off); 1456 err = -EFAULT; 1457 goto error; 1458 } 1459 } else { 1460 int i = skb_shinfo(skb)->nr_frags; 1461 struct page_frag *pfrag = sk_page_frag(sk); 1462 1463 err = -ENOMEM; 1464 if (!sk_page_frag_refill(sk, pfrag)) 1465 goto error; 1466 1467 if (!skb_can_coalesce(skb, i, pfrag->page, 1468 pfrag->offset)) { 1469 err = -EMSGSIZE; 1470 if (i == MAX_SKB_FRAGS) 1471 goto error; 1472 1473 __skb_fill_page_desc(skb, i, pfrag->page, 1474 pfrag->offset, 0); 1475 skb_shinfo(skb)->nr_frags = ++i; 1476 get_page(pfrag->page); 1477 } 1478 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1479 if (getfrag(from, 1480 page_address(pfrag->page) + pfrag->offset, 1481 offset, copy, skb->len, skb) < 0) 1482 goto error_efault; 1483 1484 pfrag->offset += copy; 1485 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1486 skb->len += copy; 1487 skb->data_len += copy; 1488 skb->truesize += copy; 1489 atomic_add(copy, &sk->sk_wmem_alloc); 1490 } 1491 offset += copy; 1492 length -= copy; 1493 } 1494 1495 return 0; 1496 1497 error_efault: 1498 err = -EFAULT; 1499 error: 1500 cork->length -= length; 1501 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1502 return err; 1503 } 1504 EXPORT_SYMBOL_GPL(ip6_append_data); 1505 1506 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np) 1507 { 1508 if (np->cork.opt) { 1509 kfree(np->cork.opt->dst0opt); 1510 kfree(np->cork.opt->dst1opt); 1511 kfree(np->cork.opt->hopopt); 1512 kfree(np->cork.opt->srcrt); 1513 kfree(np->cork.opt); 1514 np->cork.opt = NULL; 1515 } 1516 1517 if (inet->cork.base.dst) { 1518 dst_release(inet->cork.base.dst); 1519 inet->cork.base.dst = NULL; 1520 inet->cork.base.flags &= ~IPCORK_ALLFRAG; 1521 } 1522 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1523 } 1524 1525 int ip6_push_pending_frames(struct sock *sk) 1526 { 1527 struct sk_buff *skb, *tmp_skb; 1528 struct sk_buff **tail_skb; 1529 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1530 struct inet_sock *inet = inet_sk(sk); 1531 struct ipv6_pinfo *np = inet6_sk(sk); 1532 struct net *net = sock_net(sk); 1533 struct ipv6hdr *hdr; 1534 struct ipv6_txoptions *opt = np->cork.opt; 1535 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst; 1536 struct flowi6 *fl6 = &inet->cork.fl.u.ip6; 1537 unsigned char proto = fl6->flowi6_proto; 1538 int err = 0; 1539 1540 skb = __skb_dequeue(&sk->sk_write_queue); 1541 if (skb == NULL) 1542 goto out; 1543 tail_skb = &(skb_shinfo(skb)->frag_list); 1544 1545 /* move skb->data to ip header from ext header */ 1546 if (skb->data < skb_network_header(skb)) 1547 __skb_pull(skb, skb_network_offset(skb)); 1548 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1549 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1550 *tail_skb = tmp_skb; 1551 tail_skb = &(tmp_skb->next); 1552 skb->len += tmp_skb->len; 1553 skb->data_len += tmp_skb->len; 1554 skb->truesize += tmp_skb->truesize; 1555 tmp_skb->destructor = NULL; 1556 tmp_skb->sk = NULL; 1557 } 1558 1559 /* Allow local fragmentation. */ 1560 skb->ignore_df = ip6_sk_ignore_df(sk); 1561 1562 *final_dst = fl6->daddr; 1563 __skb_pull(skb, skb_network_header_len(skb)); 1564 if (opt && opt->opt_flen) 1565 ipv6_push_frag_opts(skb, opt, &proto); 1566 if (opt && opt->opt_nflen) 1567 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1568 1569 skb_push(skb, sizeof(struct ipv6hdr)); 1570 skb_reset_network_header(skb); 1571 hdr = ipv6_hdr(skb); 1572 1573 ip6_flow_hdr(hdr, np->cork.tclass, 1574 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1575 np->autoflowlabel)); 1576 hdr->hop_limit = np->cork.hop_limit; 1577 hdr->nexthdr = proto; 1578 hdr->saddr = fl6->saddr; 1579 hdr->daddr = *final_dst; 1580 1581 skb->priority = sk->sk_priority; 1582 skb->mark = sk->sk_mark; 1583 1584 skb_dst_set(skb, dst_clone(&rt->dst)); 1585 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1586 if (proto == IPPROTO_ICMPV6) { 1587 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1588 1589 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1590 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1591 } 1592 1593 err = ip6_local_out(skb); 1594 if (err) { 1595 if (err > 0) 1596 err = net_xmit_errno(err); 1597 if (err) 1598 goto error; 1599 } 1600 1601 out: 1602 ip6_cork_release(inet, np); 1603 return err; 1604 error: 1605 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1606 goto out; 1607 } 1608 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1609 1610 void ip6_flush_pending_frames(struct sock *sk) 1611 { 1612 struct sk_buff *skb; 1613 1614 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1615 if (skb_dst(skb)) 1616 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1617 IPSTATS_MIB_OUTDISCARDS); 1618 kfree_skb(skb); 1619 } 1620 1621 ip6_cork_release(inet_sk(sk), inet6_sk(sk)); 1622 } 1623 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1624