Pileus Git - ~andy/linux/blob - net/ipv6/ip6_output.c

   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, &ipv6_hdr(skb)->daddr);
 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_BH(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                 return ip6_fragment(skb, ip6_finish_output2);
 130         else
 131                 return ip6_finish_output2(skb);
 132 }
 133
 134 int ip6_output(struct sk_buff *skb)
 135 {
 136         struct net_device *dev = skb_dst(skb)->dev;
 137         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 138         if (unlikely(idev->cnf.disable_ipv6)) {
 139                 IP6_INC_STATS(dev_net(dev), idev,
 140                               IPSTATS_MIB_OUTDISCARDS);
 141                 kfree_skb(skb);
 142                 return 0;
 143         }
 144
 145         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
 146                             ip6_finish_output,
 147                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 148 }
 149
 150 /*
 151  *      xmit an sk_buff (used by TCP, SCTP and DCCP)
 152  */
 153
 154 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 155              struct ipv6_txoptions *opt, int tclass)
 156 {
 157         struct net *net = sock_net(sk);
 158         struct ipv6_pinfo *np = inet6_sk(sk);
 159         struct in6_addr *first_hop = &fl6->daddr;
 160         struct dst_entry *dst = skb_dst(skb);
 161         struct ipv6hdr *hdr;
 162         u8  proto = fl6->flowi6_proto;
 163         int seg_len = skb->len;
 164         int hlimit = -1;
 165         u32 mtu;
 166
 167         if (opt) {
 168                 unsigned int head_room;
 169
 170                 /* First: exthdrs may take lots of space (~8K for now)
 171                    MAX_HEADER is not enough.
 172                  */
 173                 head_room = opt->opt_nflen + opt->opt_flen;
 174                 seg_len += head_room;
 175                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 176
 177                 if (skb_headroom(skb) < head_room) {
 178                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 179                         if (skb2 == NULL) {
 180                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 181                                               IPSTATS_MIB_OUTDISCARDS);
 182                                 kfree_skb(skb);
 183                                 return -ENOBUFS;
 184                         }
 185                         consume_skb(skb);
 186                         skb = skb2;
 187                         skb_set_owner_w(skb, sk);
 188                 }
 189                 if (opt->opt_flen)
 190                         ipv6_push_frag_opts(skb, opt, &proto);
 191                 if (opt->opt_nflen)
 192                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 193         }
 194
 195         skb_push(skb, sizeof(struct ipv6hdr));
 196         skb_reset_network_header(skb);
 197         hdr = ipv6_hdr(skb);
 198
 199         /*
 200          *      Fill in the IPv6 header
 201          */
 202         if (np)
 203                 hlimit = np->hop_limit;
 204         if (hlimit < 0)
 205                 hlimit = ip6_dst_hoplimit(dst);
 206
 207         ip6_flow_hdr(hdr, tclass, fl6->flowlabel);
 208
 209         hdr->payload_len = htons(seg_len);
 210         hdr->nexthdr = proto;
 211         hdr->hop_limit = hlimit;
 212
 213         hdr->saddr = fl6->saddr;
 214         hdr->daddr = *first_hop;
 215
 216         skb->protocol = htons(ETH_P_IPV6);
 217         skb->priority = sk->sk_priority;
 218         skb->mark = sk->sk_mark;
 219
 220         mtu = dst_mtu(dst);
 221         if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
 222                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 223                               IPSTATS_MIB_OUT, skb->len);
 224                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 225                                dst->dev, dst_output);
 226         }
 227
 228         skb->dev = dst->dev;
 229         ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
 230         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 231         kfree_skb(skb);
 232         return -EMSGSIZE;
 233 }
 234
 235 EXPORT_SYMBOL(ip6_xmit);
 236
 237 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 238 {
 239         struct ip6_ra_chain *ra;
 240         struct sock *last = NULL;
 241
 242         read_lock(&ip6_ra_lock);
 243         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 244                 struct sock *sk = ra->sk;
 245                 if (sk && ra->sel == sel &&
 246                     (!sk->sk_bound_dev_if ||
 247                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 248                         if (last) {
 249                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 250                                 if (skb2)
 251                                         rawv6_rcv(last, skb2);
 252                         }
 253                         last = sk;
 254                 }
 255         }
 256
 257         if (last) {
 258                 rawv6_rcv(last, skb);
 259                 read_unlock(&ip6_ra_lock);
 260                 return 1;
 261         }
 262         read_unlock(&ip6_ra_lock);
 263         return 0;
 264 }
 265
 266 static int ip6_forward_proxy_check(struct sk_buff *skb)
 267 {
 268         struct ipv6hdr *hdr = ipv6_hdr(skb);
 269         u8 nexthdr = hdr->nexthdr;
 270         __be16 frag_off;
 271         int offset;
 272
 273         if (ipv6_ext_hdr(nexthdr)) {
 274                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 275                 if (offset < 0)
 276                         return 0;
 277         } else
 278                 offset = sizeof(struct ipv6hdr);
 279
 280         if (nexthdr == IPPROTO_ICMPV6) {
 281                 struct icmp6hdr *icmp6;
 282
 283                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 284                                          offset + 1 - skb->data)))
 285                         return 0;
 286
 287                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 288
 289                 switch (icmp6->icmp6_type) {
 290                 case NDISC_ROUTER_SOLICITATION:
 291                 case NDISC_ROUTER_ADVERTISEMENT:
 292                 case NDISC_NEIGHBOUR_SOLICITATION:
 293                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 294                 case NDISC_REDIRECT:
 295                         /* For reaction involving unicast neighbor discovery
 296                          * message destined to the proxied address, pass it to
 297                          * input function.
 298                          */
 299                         return 1;
 300                 default:
 301                         break;
 302                 }
 303         }
 304
 305         /*
 306          * The proxying router can't forward traffic sent to a link-local
 307          * address, so signal the sender and discard the packet. This
 308          * behavior is clarified by the MIPv6 specification.
 309          */
 310         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 311                 dst_link_failure(skb);
 312                 return -1;
 313         }
 314
 315         return 0;
 316 }
 317
 318 static inline int ip6_forward_finish(struct sk_buff *skb)
 319 {
 320         return dst_output(skb);
 321 }
 322
 323 int ip6_forward(struct sk_buff *skb)
 324 {
 325         struct dst_entry *dst = skb_dst(skb);
 326         struct ipv6hdr *hdr = ipv6_hdr(skb);
 327         struct inet6_skb_parm *opt = IP6CB(skb);
 328         struct net *net = dev_net(dst->dev);
 329         u32 mtu;
 330
 331         if (net->ipv6.devconf_all->forwarding == 0)
 332                 goto error;
 333
 334         if (skb_warn_if_lro(skb))
 335                 goto drop;
 336
 337         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 338                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 339                 goto drop;
 340         }
 341
 342         if (skb->pkt_type != PACKET_HOST)
 343                 goto drop;
 344
 345         skb_forward_csum(skb);
 346
 347         /*
 348          *      We DO NOT make any processing on
 349          *      RA packets, pushing them to user level AS IS
 350          *      without ane WARRANTY that application will be able
 351          *      to interpret them. The reason is that we
 352          *      cannot make anything clever here.
 353          *
 354          *      We are not end-node, so that if packet contains
 355          *      AH/ESP, we cannot make anything.
 356          *      Defragmentation also would be mistake, RA packets
 357          *      cannot be fragmented, because there is no warranty
 358          *      that different fragments will go along one path. --ANK
 359          */
 360         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 361                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 362                         return 0;
 363         }
 364
 365         /*
 366          *      check and decrement ttl
 367          */
 368         if (hdr->hop_limit <= 1) {
 369                 /* Force OUTPUT device used as source address */
 370                 skb->dev = dst->dev;
 371                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 372                 IP6_INC_STATS_BH(net,
 373                                  ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 374
 375                 kfree_skb(skb);
 376                 return -ETIMEDOUT;
 377         }
 378
 379         /* XXX: idev->cnf.proxy_ndp? */
 380         if (net->ipv6.devconf_all->proxy_ndp &&
 381             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 382                 int proxied = ip6_forward_proxy_check(skb);
 383                 if (proxied > 0)
 384                         return ip6_input(skb);
 385                 else if (proxied < 0) {
 386                         IP6_INC_STATS(net, ip6_dst_idev(dst),
 387                                       IPSTATS_MIB_INDISCARDS);
 388                         goto drop;
 389                 }
 390         }
 391
 392         if (!xfrm6_route_forward(skb)) {
 393                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 394                 goto drop;
 395         }
 396         dst = skb_dst(skb);
 397
 398         /* IPv6 specs say nothing about it, but it is clear that we cannot
 399            send redirects to source routed frames.
 400            We don't send redirects to frames decapsulated from IPsec.
 401          */
 402         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 403                 struct in6_addr *target = NULL;
 404                 struct inet_peer *peer;
 405                 struct rt6_info *rt;
 406
 407                 /*
 408                  *      incoming and outgoing devices are the same
 409                  *      send a redirect.
 410                  */
 411
 412                 rt = (struct rt6_info *) dst;
 413                 if (rt->rt6i_flags & RTF_GATEWAY)
 414                         target = &rt->rt6i_gateway;
 415                 else
 416                         target = &hdr->daddr;
 417
 418                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 419
 420                 /* Limit redirects both by destination (here)
 421                    and by source (inside ndisc_send_redirect)
 422                  */
 423                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 424                         ndisc_send_redirect(skb, target);
 425                 if (peer)
 426                         inet_putpeer(peer);
 427         } else {
 428                 int addrtype = ipv6_addr_type(&hdr->saddr);
 429
 430                 /* This check is security critical. */
 431                 if (addrtype == IPV6_ADDR_ANY ||
 432                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 433                         goto error;
 434                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 435                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 436                                     ICMPV6_NOT_NEIGHBOUR, 0);
 437                         goto error;
 438                 }
 439         }
 440
 441         mtu = dst_mtu(dst);
 442         if (mtu < IPV6_MIN_MTU)
 443                 mtu = IPV6_MIN_MTU;
 444
 445         if ((!skb->local_df && skb->len > mtu && !skb_is_gso(skb)) ||
 446             (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)) {
 447                 /* Again, force OUTPUT device used as source address */
 448                 skb->dev = dst->dev;
 449                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 450                 IP6_INC_STATS_BH(net,
 451                                  ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
 452                 IP6_INC_STATS_BH(net,
 453                                  ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
 454                 kfree_skb(skb);
 455                 return -EMSGSIZE;
 456         }
 457
 458         if (skb_cow(skb, dst->dev->hard_header_len)) {
 459                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
 460                 goto drop;
 461         }
 462
 463         hdr = ipv6_hdr(skb);
 464
 465         /* Mangling hops number delayed to point after skb COW */
 466
 467         hdr->hop_limit--;
 468
 469         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 470         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 471         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 472                        ip6_forward_finish);
 473
 474 error:
 475         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 476 drop:
 477         kfree_skb(skb);
 478         return -EINVAL;
 479 }
 480
 481 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 482 {
 483         to->pkt_type = from->pkt_type;
 484         to->priority = from->priority;
 485         to->protocol = from->protocol;
 486         skb_dst_drop(to);
 487         skb_dst_set(to, dst_clone(skb_dst(from)));
 488         to->dev = from->dev;
 489         to->mark = from->mark;
 490
 491 #ifdef CONFIG_NET_SCHED
 492         to->tc_index = from->tc_index;
 493 #endif
 494         nf_copy(to, from);
 495 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 496         to->nf_trace = from->nf_trace;
 497 #endif
 498         skb_copy_secmark(to, from);
 499 }
 500
 501 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 502 {
 503         struct sk_buff *frag;
 504         struct rt6_info *rt = (struct rt6_info*)skb_dst(skb);
 505         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 506         struct ipv6hdr *tmp_hdr;
 507         struct frag_hdr *fh;
 508         unsigned int mtu, hlen, left, len;
 509         int hroom, troom;
 510         __be32 frag_id = 0;
 511         int ptr, offset = 0, err=0;
 512         u8 *prevhdr, nexthdr = 0;
 513         struct net *net = dev_net(skb_dst(skb)->dev);
 514
 515         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 516         nexthdr = *prevhdr;
 517
 518         mtu = ip6_skb_dst_mtu(skb);
 519
 520         /* We must not fragment if the socket is set to force MTU discovery
 521          * or if the skb it not generated by a local socket.
 522          */
 523         if (unlikely(!skb->local_df && skb->len > mtu) ||
 524                      (IP6CB(skb)->frag_max_size &&
 525                       IP6CB(skb)->frag_max_size > mtu)) {
 526                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 527                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 528
 529                 skb->dev = skb_dst(skb)->dev;
 530                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 531                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 532                               IPSTATS_MIB_FRAGFAILS);
 533                 kfree_skb(skb);
 534                 return -EMSGSIZE;
 535         }
 536
 537         if (np && np->frag_size < mtu) {
 538                 if (np->frag_size)
 539                         mtu = np->frag_size;
 540         }
 541         mtu -= hlen + sizeof(struct frag_hdr);
 542
 543         if (skb_has_frag_list(skb)) {
 544                 int first_len = skb_pagelen(skb);
 545                 struct sk_buff *frag2;
 546
 547                 if (first_len - hlen > mtu ||
 548                     ((first_len - hlen) & 7) ||
 549                     skb_cloned(skb))
 550                         goto slow_path;
 551
 552                 skb_walk_frags(skb, frag) {
 553                         /* Correct geometry. */
 554                         if (frag->len > mtu ||
 555                             ((frag->len & 7) && frag->next) ||
 556                             skb_headroom(frag) < hlen)
 557                                 goto slow_path_clean;
 558
 559                         /* Partially cloned skb? */
 560                         if (skb_shared(frag))
 561                                 goto slow_path_clean;
 562
 563                         BUG_ON(frag->sk);
 564                         if (skb->sk) {
 565                                 frag->sk = skb->sk;
 566                                 frag->destructor = sock_wfree;
 567                         }
 568                         skb->truesize -= frag->truesize;
 569                 }
 570
 571                 err = 0;
 572                 offset = 0;
 573                 frag = skb_shinfo(skb)->frag_list;
 574                 skb_frag_list_init(skb);
 575                 /* BUILD HEADER */
 576
 577                 *prevhdr = NEXTHDR_FRAGMENT;
 578                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 579                 if (!tmp_hdr) {
 580                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 581                                       IPSTATS_MIB_FRAGFAILS);
 582                         return -ENOMEM;
 583                 }
 584
 585                 __skb_pull(skb, hlen);
 586                 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
 587                 __skb_push(skb, hlen);
 588                 skb_reset_network_header(skb);
 589                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 590
 591                 ipv6_select_ident(fh, rt);
 592                 fh->nexthdr = nexthdr;
 593                 fh->reserved = 0;
 594                 fh->frag_off = htons(IP6_MF);
 595                 frag_id = fh->identification;
 596
 597                 first_len = skb_pagelen(skb);
 598                 skb->data_len = first_len - skb_headlen(skb);
 599                 skb->len = first_len;
 600                 ipv6_hdr(skb)->payload_len = htons(first_len -
 601                                                    sizeof(struct ipv6hdr));
 602
 603                 dst_hold(&rt->dst);
 604
 605                 for (;;) {
 606                         /* Prepare header of the next frame,
 607                          * before previous one went down. */
 608                         if (frag) {
 609                                 frag->ip_summed = CHECKSUM_NONE;
 610                                 skb_reset_transport_header(frag);
 611                                 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 612                                 __skb_push(frag, hlen);
 613                                 skb_reset_network_header(frag);
 614                                 memcpy(skb_network_header(frag), tmp_hdr,
 615                                        hlen);
 616                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 617                                 fh->nexthdr = nexthdr;
 618                                 fh->reserved = 0;
 619                                 fh->frag_off = htons(offset);
 620                                 if (frag->next != NULL)
 621                                         fh->frag_off |= htons(IP6_MF);
 622                                 fh->identification = frag_id;
 623                                 ipv6_hdr(frag)->payload_len =
 624                                                 htons(frag->len -
 625                                                       sizeof(struct ipv6hdr));
 626                                 ip6_copy_metadata(frag, skb);
 627                         }
 628
 629                         err = output(skb);
 630                         if(!err)
 631                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 632                                               IPSTATS_MIB_FRAGCREATES);
 633
 634                         if (err || !frag)
 635                                 break;
 636
 637                         skb = frag;
 638                         frag = skb->next;
 639                         skb->next = NULL;
 640                 }
 641
 642                 kfree(tmp_hdr);
 643
 644                 if (err == 0) {
 645                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 646                                       IPSTATS_MIB_FRAGOKS);
 647                         ip6_rt_put(rt);
 648                         return 0;
 649                 }
 650
 651                 while (frag) {
 652                         skb = frag->next;
 653                         kfree_skb(frag);
 654                         frag = skb;
 655                 }
 656
 657                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 658                               IPSTATS_MIB_FRAGFAILS);
 659                 ip6_rt_put(rt);
 660                 return err;
 661
 662 slow_path_clean:
 663                 skb_walk_frags(skb, frag2) {
 664                         if (frag2 == frag)
 665                                 break;
 666                         frag2->sk = NULL;
 667                         frag2->destructor = NULL;
 668                         skb->truesize += frag2->truesize;
 669                 }
 670         }
 671
 672 slow_path:
 673         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 674             skb_checksum_help(skb))
 675                 goto fail;
 676
 677         left = skb->len - hlen;         /* Space per frame */
 678         ptr = hlen;                     /* Where to start from */
 679
 680         /*
 681          *      Fragment the datagram.
 682          */
 683
 684         *prevhdr = NEXTHDR_FRAGMENT;
 685         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 686         troom = rt->dst.dev->needed_tailroom;
 687
 688         /*
 689          *      Keep copying data until we run out.
 690          */
 691         while(left > 0) {
 692                 len = left;
 693                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 694                 if (len > mtu)
 695                         len = mtu;
 696                 /* IF: we are not sending up to and including the packet end
 697                    then align the next start on an eight byte boundary */
 698                 if (len < left) {
 699                         len &= ~7;
 700                 }
 701                 /*
 702                  *      Allocate buffer.
 703                  */
 704
 705                 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 706                                       hroom + troom, GFP_ATOMIC)) == NULL) {
 707                         NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 708                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 709                                       IPSTATS_MIB_FRAGFAILS);
 710                         err = -ENOMEM;
 711                         goto fail;
 712                 }
 713
 714                 /*
 715                  *      Set up data on packet
 716                  */
 717
 718                 ip6_copy_metadata(frag, skb);
 719                 skb_reserve(frag, hroom);
 720                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 721                 skb_reset_network_header(frag);
 722                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 723                 frag->transport_header = (frag->network_header + hlen +
 724                                           sizeof(struct frag_hdr));
 725
 726                 /*
 727                  *      Charge the memory for the fragment to any owner
 728                  *      it might possess
 729                  */
 730                 if (skb->sk)
 731                         skb_set_owner_w(frag, skb->sk);
 732
 733                 /*
 734                  *      Copy the packet header into the new buffer.
 735                  */
 736                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 737
 738                 /*
 739                  *      Build fragment header.
 740                  */
 741                 fh->nexthdr = nexthdr;
 742                 fh->reserved = 0;
 743                 if (!frag_id) {
 744                         ipv6_select_ident(fh, rt);
 745                         frag_id = fh->identification;
 746                 } else
 747                         fh->identification = frag_id;
 748
 749                 /*
 750                  *      Copy a block of the IP datagram.
 751                  */
 752                 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
 753                         BUG();
 754                 left -= len;
 755
 756                 fh->frag_off = htons(offset);
 757                 if (left > 0)
 758                         fh->frag_off |= htons(IP6_MF);
 759                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 760                                                     sizeof(struct ipv6hdr));
 761
 762                 ptr += len;
 763                 offset += len;
 764
 765                 /*
 766                  *      Put this fragment into the sending queue.
 767                  */
 768                 err = output(frag);
 769                 if (err)
 770                         goto fail;
 771
 772                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 773                               IPSTATS_MIB_FRAGCREATES);
 774         }
 775         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 776                       IPSTATS_MIB_FRAGOKS);
 777         consume_skb(skb);
 778         return err;
 779
 780 fail:
 781         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 782                       IPSTATS_MIB_FRAGFAILS);
 783         kfree_skb(skb);
 784         return err;
 785 }
 786
 787 static inline int ip6_rt_check(const struct rt6key *rt_key,
 788                                const struct in6_addr *fl_addr,
 789                                const struct in6_addr *addr_cache)
 790 {
 791         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 792                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 793 }
 794
 795 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 796                                           struct dst_entry *dst,
 797                                           const struct flowi6 *fl6)
 798 {
 799         struct ipv6_pinfo *np = inet6_sk(sk);
 800         struct rt6_info *rt;
 801
 802         if (!dst)
 803                 goto out;
 804
 805         if (dst->ops->family != AF_INET6) {
 806                 dst_release(dst);
 807                 return NULL;
 808         }
 809
 810         rt = (struct rt6_info *)dst;
 811         /* Yes, checking route validity in not connected
 812          * case is not very simple. Take into account,
 813          * that we do not support routing by source, TOS,
 814          * and MSG_DONTROUTE            --ANK (980726)
 815          *
 816          * 1. ip6_rt_check(): If route was host route,
 817          *    check that cached destination is current.
 818          *    If it is network route, we still may
 819          *    check its validity using saved pointer
 820          *    to the last used address: daddr_cache.
 821          *    We do not want to save whole address now,
 822          *    (because main consumer of this service
 823          *    is tcp, which has not this problem),
 824          *    so that the last trick works only on connected
 825          *    sockets.
 826          * 2. oif also should be the same.
 827          */
 828         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 829 #ifdef CONFIG_IPV6_SUBTREES
 830             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 831 #endif
 832             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 833                 dst_release(dst);
 834                 dst = NULL;
 835         }
 836
 837 out:
 838         return dst;
 839 }
 840
 841 static int ip6_dst_lookup_tail(struct sock *sk,
 842                                struct dst_entry **dst, struct flowi6 *fl6)
 843 {
 844         struct net *net = sock_net(sk);
 845 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 846         struct neighbour *n;
 847         struct rt6_info *rt;
 848 #endif
 849         int err;
 850
 851         if (*dst == NULL)
 852                 *dst = ip6_route_output(net, sk, fl6);
 853
 854         if ((err = (*dst)->error))
 855                 goto out_err_release;
 856
 857         if (ipv6_addr_any(&fl6->saddr)) {
 858                 struct rt6_info *rt = (struct rt6_info *) *dst;
 859                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 860                                           sk ? inet6_sk(sk)->srcprefs : 0,
 861                                           &fl6->saddr);
 862                 if (err)
 863                         goto out_err_release;
 864         }
 865
 866 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 867         /*
 868          * Here if the dst entry we've looked up
 869          * has a neighbour entry that is in the INCOMPLETE
 870          * state and the src address from the flow is
 871          * marked as OPTIMISTIC, we release the found
 872          * dst entry and replace it instead with the
 873          * dst entry of the nexthop router
 874          */
 875         rt = (struct rt6_info *) *dst;
 876         rcu_read_lock_bh();
 877         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt, &fl6->daddr));
 878         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 879         rcu_read_unlock_bh();
 880
 881         if (err) {
 882                 struct inet6_ifaddr *ifp;
 883                 struct flowi6 fl_gw6;
 884                 int redirect;
 885
 886                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 887                                       (*dst)->dev, 1);
 888
 889                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 890                 if (ifp)
 891                         in6_ifa_put(ifp);
 892
 893                 if (redirect) {
 894                         /*
 895                          * We need to get the dst entry for the
 896                          * default router instead
 897                          */
 898                         dst_release(*dst);
 899                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 900                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 901                         *dst = ip6_route_output(net, sk, &fl_gw6);
 902                         if ((err = (*dst)->error))
 903                                 goto out_err_release;
 904                 }
 905         }
 906 #endif
 907
 908         return 0;
 909
 910 out_err_release:
 911         if (err == -ENETUNREACH)
 912                 IP6_INC_STATS_BH(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 913         dst_release(*dst);
 914         *dst = NULL;
 915         return err;
 916 }
 917
 918 /**
 919  *      ip6_dst_lookup - perform route lookup on flow
 920  *      @sk: socket which provides route info
 921  *      @dst: pointer to dst_entry * for result
 922  *      @fl6: flow to lookup
 923  *
 924  *      This function performs a route lookup on the given flow.
 925  *
 926  *      It returns zero on success, or a standard errno code on error.
 927  */
 928 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 929 {
 930         *dst = NULL;
 931         return ip6_dst_lookup_tail(sk, dst, fl6);
 932 }
 933 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 934
 935 /**
 936  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 937  *      @sk: socket which provides route info
 938  *      @fl6: flow to lookup
 939  *      @final_dst: final destination address for ipsec lookup
 940  *      @can_sleep: we are in a sleepable context
 941  *
 942  *      This function performs a route lookup on the given flow.
 943  *
 944  *      It returns a valid dst pointer on success, or a pointer encoded
 945  *      error code.
 946  */
 947 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 948                                       const struct in6_addr *final_dst,
 949                                       bool can_sleep)
 950 {
 951         struct dst_entry *dst = NULL;
 952         int err;
 953
 954         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 955         if (err)
 956                 return ERR_PTR(err);
 957         if (final_dst)
 958                 fl6->daddr = *final_dst;
 959         if (can_sleep)
 960                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
 961
 962         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
 963 }
 964 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 965
 966 /**
 967  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
 968  *      @sk: socket which provides the dst cache and route info
 969  *      @fl6: flow to lookup
 970  *      @final_dst: final destination address for ipsec lookup
 971  *      @can_sleep: we are in a sleepable context
 972  *
 973  *      This function performs a route lookup on the given flow with the
 974  *      possibility of using the cached route in the socket if it is valid.
 975  *      It will take the socket dst lock when operating on the dst cache.
 976  *      As a result, this function can only be used in process context.
 977  *
 978  *      It returns a valid dst pointer on success, or a pointer encoded
 979  *      error code.
 980  */
 981 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 982                                          const struct in6_addr *final_dst,
 983                                          bool can_sleep)
 984 {
 985         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
 986         int err;
 987
 988         dst = ip6_sk_dst_check(sk, dst, fl6);
 989
 990         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 991         if (err)
 992                 return ERR_PTR(err);
 993         if (final_dst)
 994                 fl6->daddr = *final_dst;
 995         if (can_sleep)
 996                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
 997
 998         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
 999 }
1000 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1001
1002 static inline int ip6_ufo_append_data(struct sock *sk,
1003                         int getfrag(void *from, char *to, int offset, int len,
1004                         int odd, struct sk_buff *skb),
1005                         void *from, int length, int hh_len, int fragheaderlen,
1006                         int transhdrlen, int mtu,unsigned int flags,
1007                         struct rt6_info *rt)
1008
1009 {
1010         struct sk_buff *skb;
1011         int err;
1012
1013         /* There is support for UDP large send offload by network
1014          * device, so create one single skb packet containing complete
1015          * udp datagram
1016          */
1017         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1018                 struct frag_hdr fhdr;
1019
1020                 skb = sock_alloc_send_skb(sk,
1021                         hh_len + fragheaderlen + transhdrlen + 20,
1022                         (flags & MSG_DONTWAIT), &err);
1023                 if (skb == NULL)
1024                         return err;
1025
1026                 /* reserve space for Hardware header */
1027                 skb_reserve(skb, hh_len);
1028
1029                 /* create space for UDP/IP header */
1030                 skb_put(skb,fragheaderlen + transhdrlen);
1031
1032                 /* initialize network header pointer */
1033                 skb_reset_network_header(skb);
1034
1035                 /* initialize protocol header pointer */
1036                 skb->transport_header = skb->network_header + fragheaderlen;
1037
1038                 skb->protocol = htons(ETH_P_IPV6);
1039                 skb->ip_summed = CHECKSUM_PARTIAL;
1040                 skb->csum = 0;
1041
1042                 /* Specify the length of each IPv6 datagram fragment.
1043                  * It has to be a multiple of 8.
1044                  */
1045                 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1046                                              sizeof(struct frag_hdr)) & ~7;
1047                 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1048                 ipv6_select_ident(&fhdr, rt);
1049                 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1050                 __skb_queue_tail(&sk->sk_write_queue, skb);
1051         }
1052
1053         return skb_append_datato_frags(sk, skb, getfrag, from,
1054                                        (length - transhdrlen));
1055 }
1056
1057 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1058                                                gfp_t gfp)
1059 {
1060         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1061 }
1062
1063 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1064                                                 gfp_t gfp)
1065 {
1066         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1067 }
1068
1069 static void ip6_append_data_mtu(unsigned int *mtu,
1070                                 int *maxfraglen,
1071                                 unsigned int fragheaderlen,
1072                                 struct sk_buff *skb,
1073                                 struct rt6_info *rt,
1074                                 bool pmtuprobe)
1075 {
1076         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1077                 if (skb == NULL) {
1078                         /* first fragment, reserve header_len */
1079                         *mtu = *mtu - rt->dst.header_len;
1080
1081                 } else {
1082                         /*
1083                          * this fragment is not first, the headers
1084                          * space is regarded as data space.
1085                          */
1086                         *mtu = min(*mtu, pmtuprobe ?
1087                                    rt->dst.dev->mtu :
1088                                    dst_mtu(rt->dst.path));
1089                 }
1090                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1091                               + fragheaderlen - sizeof(struct frag_hdr);
1092         }
1093 }
1094
1095 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1096         int offset, int len, int odd, struct sk_buff *skb),
1097         void *from, int length, int transhdrlen,
1098         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1099         struct rt6_info *rt, unsigned int flags, int dontfrag)
1100 {
1101         struct inet_sock *inet = inet_sk(sk);
1102         struct ipv6_pinfo *np = inet6_sk(sk);
1103         struct inet_cork *cork;
1104         struct sk_buff *skb, *skb_prev = NULL;
1105         unsigned int maxfraglen, fragheaderlen, mtu;
1106         int exthdrlen;
1107         int dst_exthdrlen;
1108         int hh_len;
1109         int copy;
1110         int err;
1111         int offset = 0;
1112         __u8 tx_flags = 0;
1113
1114         if (flags&MSG_PROBE)
1115                 return 0;
1116         cork = &inet->cork.base;
1117         if (skb_queue_empty(&sk->sk_write_queue)) {
1118                 /*
1119                  * setup for corking
1120                  */
1121                 if (opt) {
1122                         if (WARN_ON(np->cork.opt))
1123                                 return -EINVAL;
1124
1125                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1126                         if (unlikely(np->cork.opt == NULL))
1127                                 return -ENOBUFS;
1128
1129                         np->cork.opt->tot_len = opt->tot_len;
1130                         np->cork.opt->opt_flen = opt->opt_flen;
1131                         np->cork.opt->opt_nflen = opt->opt_nflen;
1132
1133                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1134                                                             sk->sk_allocation);
1135                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1136                                 return -ENOBUFS;
1137
1138                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1139                                                             sk->sk_allocation);
1140                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1141                                 return -ENOBUFS;
1142
1143                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1144                                                            sk->sk_allocation);
1145                         if (opt->hopopt && !np->cork.opt->hopopt)
1146                                 return -ENOBUFS;
1147
1148                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1149                                                             sk->sk_allocation);
1150                         if (opt->srcrt && !np->cork.opt->srcrt)
1151                                 return -ENOBUFS;
1152
1153                         /* need source address above miyazawa*/
1154                 }
1155                 dst_hold(&rt->dst);
1156                 cork->dst = &rt->dst;
1157                 inet->cork.fl.u.ip6 = *fl6;
1158                 np->cork.hop_limit = hlimit;
1159                 np->cork.tclass = tclass;
1160                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1161                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1162                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1163                 else
1164                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1165                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1166                 if (np->frag_size < mtu) {
1167                         if (np->frag_size)
1168                                 mtu = np->frag_size;
1169                 }
1170                 cork->fragsize = mtu;
1171                 if (dst_allfrag(rt->dst.path))
1172                         cork->flags |= IPCORK_ALLFRAG;
1173                 cork->length = 0;
1174                 exthdrlen = (opt ? opt->opt_flen : 0);
1175                 length += exthdrlen;
1176                 transhdrlen += exthdrlen;
1177                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1178         } else {
1179                 rt = (struct rt6_info *)cork->dst;
1180                 fl6 = &inet->cork.fl.u.ip6;
1181                 opt = np->cork.opt;
1182                 transhdrlen = 0;
1183                 exthdrlen = 0;
1184                 dst_exthdrlen = 0;
1185                 mtu = cork->fragsize;
1186         }
1187
1188         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1189
1190         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1191                         (opt ? opt->opt_nflen : 0);
1192         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1193
1194         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1195                 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1196                         ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen);
1197                         return -EMSGSIZE;
1198                 }
1199         }
1200
1201         /* For UDP, check if TX timestamp is enabled */
1202         if (sk->sk_type == SOCK_DGRAM)
1203                 sock_tx_timestamp(sk, &tx_flags);
1204
1205         /*
1206          * Let's try using as much space as possible.
1207          * Use MTU if total length of the message fits into the MTU.
1208          * Otherwise, we need to reserve fragment header and
1209          * fragment alignment (= 8-15 octects, in total).
1210          *
1211          * Note that we may need to "move" the data from the tail of
1212          * of the buffer to the new fragment when we split
1213          * the message.
1214          *
1215          * FIXME: It may be fragmented into multiple chunks
1216          *        at once if non-fragmentable extension headers
1217          *        are too large.
1218          * --yoshfuji
1219          */
1220
1221         if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP ||
1222                                            sk->sk_protocol == IPPROTO_RAW)) {
1223                 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
1224                 return -EMSGSIZE;
1225         }
1226
1227         skb = skb_peek_tail(&sk->sk_write_queue);
1228         cork->length += length;
1229         if (((length > mtu) ||
1230              (skb && skb_is_gso(skb))) &&
1231             (sk->sk_protocol == IPPROTO_UDP) &&
1232             (rt->dst.dev->features & NETIF_F_UFO)) {
1233                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1234                                           hh_len, fragheaderlen,
1235                                           transhdrlen, mtu, flags, rt);
1236                 if (err)
1237                         goto error;
1238                 return 0;
1239         }
1240
1241         if (!skb)
1242                 goto alloc_new_skb;
1243
1244         while (length > 0) {
1245                 /* Check if the remaining data fits into current packet. */
1246                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1247                 if (copy < length)
1248                         copy = maxfraglen - skb->len;
1249
1250                 if (copy <= 0) {
1251                         char *data;
1252                         unsigned int datalen;
1253                         unsigned int fraglen;
1254                         unsigned int fraggap;
1255                         unsigned int alloclen;
1256 alloc_new_skb:
1257                         /* There's no room in the current skb */
1258                         if (skb)
1259                                 fraggap = skb->len - maxfraglen;
1260                         else
1261                                 fraggap = 0;
1262                         /* update mtu and maxfraglen if necessary */
1263                         if (skb == NULL || skb_prev == NULL)
1264                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1265                                                     fragheaderlen, skb, rt,
1266                                                     np->pmtudisc ==
1267                                                     IPV6_PMTUDISC_PROBE);
1268
1269                         skb_prev = skb;
1270
1271                         /*
1272                          * If remaining data exceeds the mtu,
1273                          * we know we need more fragment(s).
1274                          */
1275                         datalen = length + fraggap;
1276
1277                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1278                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1279                         if ((flags & MSG_MORE) &&
1280                             !(rt->dst.dev->features&NETIF_F_SG))
1281                                 alloclen = mtu;
1282                         else
1283                                 alloclen = datalen + fragheaderlen;
1284
1285                         alloclen += dst_exthdrlen;
1286
1287                         if (datalen != length + fraggap) {
1288                                 /*
1289                                  * this is not the last fragment, the trailer
1290                                  * space is regarded as data space.
1291                                  */
1292                                 datalen += rt->dst.trailer_len;
1293                         }
1294
1295                         alloclen += rt->dst.trailer_len;
1296                         fraglen = datalen + fragheaderlen;
1297
1298                         /*
1299                          * We just reserve space for fragment header.
1300                          * Note: this may be overallocation if the message
1301                          * (without MSG_MORE) fits into the MTU.
1302                          */
1303                         alloclen += sizeof(struct frag_hdr);
1304
1305                         if (transhdrlen) {
1306                                 skb = sock_alloc_send_skb(sk,
1307                                                 alloclen + hh_len,
1308                                                 (flags & MSG_DONTWAIT), &err);
1309                         } else {
1310                                 skb = NULL;
1311                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1312                                     2 * sk->sk_sndbuf)
1313                                         skb = sock_wmalloc(sk,
1314                                                            alloclen + hh_len, 1,
1315                                                            sk->sk_allocation);
1316                                 if (unlikely(skb == NULL))
1317                                         err = -ENOBUFS;
1318                                 else {
1319                                         /* Only the initial fragment
1320                                          * is time stamped.
1321                                          */
1322                                         tx_flags = 0;
1323                                 }
1324                         }
1325                         if (skb == NULL)
1326                                 goto error;
1327                         /*
1328                          *      Fill in the control structures
1329                          */
1330                         skb->protocol = htons(ETH_P_IPV6);
1331                         skb->ip_summed = CHECKSUM_NONE;
1332                         skb->csum = 0;
1333                         /* reserve for fragmentation and ipsec header */
1334                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1335                                     dst_exthdrlen);
1336
1337                         if (sk->sk_type == SOCK_DGRAM)
1338                                 skb_shinfo(skb)->tx_flags = tx_flags;
1339
1340                         /*
1341                          *      Find where to start putting bytes
1342                          */
1343                         data = skb_put(skb, fraglen);
1344                         skb_set_network_header(skb, exthdrlen);
1345                         data += fragheaderlen;
1346                         skb->transport_header = (skb->network_header +
1347                                                  fragheaderlen);
1348                         if (fraggap) {
1349                                 skb->csum = skb_copy_and_csum_bits(
1350                                         skb_prev, maxfraglen,
1351                                         data + transhdrlen, fraggap, 0);
1352                                 skb_prev->csum = csum_sub(skb_prev->csum,
1353                                                           skb->csum);
1354                                 data += fraggap;
1355                                 pskb_trim_unique(skb_prev, maxfraglen);
1356                         }
1357                         copy = datalen - transhdrlen - fraggap;
1358
1359                         if (copy < 0) {
1360                                 err = -EINVAL;
1361                                 kfree_skb(skb);
1362                                 goto error;
1363                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1364                                 err = -EFAULT;
1365                                 kfree_skb(skb);
1366                                 goto error;
1367                         }
1368
1369                         offset += copy;
1370                         length -= datalen - fraggap;
1371                         transhdrlen = 0;
1372                         exthdrlen = 0;
1373                         dst_exthdrlen = 0;
1374
1375                         /*
1376                          * Put the packet on the pending queue
1377                          */
1378                         __skb_queue_tail(&sk->sk_write_queue, skb);
1379                         continue;
1380                 }
1381
1382                 if (copy > length)
1383                         copy = length;
1384
1385                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1386                         unsigned int off;
1387
1388                         off = skb->len;
1389                         if (getfrag(from, skb_put(skb, copy),
1390                                                 offset, copy, off, skb) < 0) {
1391                                 __skb_trim(skb, off);
1392                                 err = -EFAULT;
1393                                 goto error;
1394                         }
1395                 } else {
1396                         int i = skb_shinfo(skb)->nr_frags;
1397                         struct page_frag *pfrag = sk_page_frag(sk);
1398
1399                         err = -ENOMEM;
1400                         if (!sk_page_frag_refill(sk, pfrag))
1401                                 goto error;
1402
1403                         if (!skb_can_coalesce(skb, i, pfrag->page,
1404                                               pfrag->offset)) {
1405                                 err = -EMSGSIZE;
1406                                 if (i == MAX_SKB_FRAGS)
1407                                         goto error;
1408
1409                                 __skb_fill_page_desc(skb, i, pfrag->page,
1410                                                      pfrag->offset, 0);
1411                                 skb_shinfo(skb)->nr_frags = ++i;
1412                                 get_page(pfrag->page);
1413                         }
1414                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1415                         if (getfrag(from,
1416                                     page_address(pfrag->page) + pfrag->offset,
1417                                     offset, copy, skb->len, skb) < 0)
1418                                 goto error_efault;
1419
1420                         pfrag->offset += copy;
1421                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1422                         skb->len += copy;
1423                         skb->data_len += copy;
1424                         skb->truesize += copy;
1425                         atomic_add(copy, &sk->sk_wmem_alloc);
1426                 }
1427                 offset += copy;
1428                 length -= copy;
1429         }
1430
1431         return 0;
1432
1433 error_efault:
1434         err = -EFAULT;
1435 error:
1436         cork->length -= length;
1437         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1438         return err;
1439 }
1440 EXPORT_SYMBOL_GPL(ip6_append_data);
1441
1442 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1443 {
1444         if (np->cork.opt) {
1445                 kfree(np->cork.opt->dst0opt);
1446                 kfree(np->cork.opt->dst1opt);
1447                 kfree(np->cork.opt->hopopt);
1448                 kfree(np->cork.opt->srcrt);
1449                 kfree(np->cork.opt);
1450                 np->cork.opt = NULL;
1451         }
1452
1453         if (inet->cork.base.dst) {
1454                 dst_release(inet->cork.base.dst);
1455                 inet->cork.base.dst = NULL;
1456                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1457         }
1458         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1459 }
1460
1461 int ip6_push_pending_frames(struct sock *sk)
1462 {
1463         struct sk_buff *skb, *tmp_skb;
1464         struct sk_buff **tail_skb;
1465         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1466         struct inet_sock *inet = inet_sk(sk);
1467         struct ipv6_pinfo *np = inet6_sk(sk);
1468         struct net *net = sock_net(sk);
1469         struct ipv6hdr *hdr;
1470         struct ipv6_txoptions *opt = np->cork.opt;
1471         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1472         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1473         unsigned char proto = fl6->flowi6_proto;
1474         int err = 0;
1475
1476         if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1477                 goto out;
1478         tail_skb = &(skb_shinfo(skb)->frag_list);
1479
1480         /* move skb->data to ip header from ext header */
1481         if (skb->data < skb_network_header(skb))
1482                 __skb_pull(skb, skb_network_offset(skb));
1483         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1484                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1485                 *tail_skb = tmp_skb;
1486                 tail_skb = &(tmp_skb->next);
1487                 skb->len += tmp_skb->len;
1488                 skb->data_len += tmp_skb->len;
1489                 skb->truesize += tmp_skb->truesize;
1490                 tmp_skb->destructor = NULL;
1491                 tmp_skb->sk = NULL;
1492         }
1493
1494         /* Allow local fragmentation. */
1495         if (np->pmtudisc < IPV6_PMTUDISC_DO)
1496                 skb->local_df = 1;
1497
1498         *final_dst = fl6->daddr;
1499         __skb_pull(skb, skb_network_header_len(skb));
1500         if (opt && opt->opt_flen)
1501                 ipv6_push_frag_opts(skb, opt, &proto);
1502         if (opt && opt->opt_nflen)
1503                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1504
1505         skb_push(skb, sizeof(struct ipv6hdr));
1506         skb_reset_network_header(skb);
1507         hdr = ipv6_hdr(skb);
1508
1509         ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel);
1510         hdr->hop_limit = np->cork.hop_limit;
1511         hdr->nexthdr = proto;
1512         hdr->saddr = fl6->saddr;
1513         hdr->daddr = *final_dst;
1514
1515         skb->priority = sk->sk_priority;
1516         skb->mark = sk->sk_mark;
1517
1518         skb_dst_set(skb, dst_clone(&rt->dst));
1519         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1520         if (proto == IPPROTO_ICMPV6) {
1521                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1522
1523                 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type);
1524                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
1525         }
1526
1527         err = ip6_local_out(skb);
1528         if (err) {
1529                 if (err > 0)
1530                         err = net_xmit_errno(err);
1531                 if (err)
1532                         goto error;
1533         }
1534
1535 out:
1536         ip6_cork_release(inet, np);
1537         return err;
1538 error:
1539         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1540         goto out;
1541 }
1542 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1543
1544 void ip6_flush_pending_frames(struct sock *sk)
1545 {
1546         struct sk_buff *skb;
1547
1548         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1549                 if (skb_dst(skb))
1550                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1551                                       IPSTATS_MIB_OUTDISCARDS);
1552                 kfree_skb(skb);
1553         }
1554
1555         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1556 }
1557 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);