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);
 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 sk_buff *skb)
 136 {
 137         struct net_device *dev = skb_dst(skb)->dev;
 138         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(dev_net(dev), idev,
 141                               IPSTATS_MIB_OUTDISCARDS);
 142                 kfree_skb(skb);
 143                 return 0;
 144         }
 145
 146         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
 147                             ip6_finish_output,
 148                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 149 }
 150
 151 /*
 152  *      xmit an sk_buff (used by TCP, SCTP and DCCP)
 153  */
 154
 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 156              struct ipv6_txoptions *opt, int tclass)
 157 {
 158         struct net *net = sock_net(sk);
 159         struct ipv6_pinfo *np = inet6_sk(sk);
 160         struct in6_addr *first_hop = &fl6->daddr;
 161         struct dst_entry *dst = skb_dst(skb);
 162         struct ipv6hdr *hdr;
 163         u8  proto = fl6->flowi6_proto;
 164         int seg_len = skb->len;
 165         int hlimit = -1;
 166         u32 mtu;
 167
 168         if (opt) {
 169                 unsigned int head_room;
 170
 171                 /* First: exthdrs may take lots of space (~8K for now)
 172                    MAX_HEADER is not enough.
 173                  */
 174                 head_room = opt->opt_nflen + opt->opt_flen;
 175                 seg_len += head_room;
 176                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 177
 178                 if (skb_headroom(skb) < head_room) {
 179                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 180                         if (skb2 == NULL) {
 181                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 182                                               IPSTATS_MIB_OUTDISCARDS);
 183                                 kfree_skb(skb);
 184                                 return -ENOBUFS;
 185                         }
 186                         consume_skb(skb);
 187                         skb = skb2;
 188                         skb_set_owner_w(skb, sk);
 189                 }
 190                 if (opt->opt_flen)
 191                         ipv6_push_frag_opts(skb, opt, &proto);
 192                 if (opt->opt_nflen)
 193                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 194         }
 195
 196         skb_push(skb, sizeof(struct ipv6hdr));
 197         skb_reset_network_header(skb);
 198         hdr = ipv6_hdr(skb);
 199
 200         /*
 201          *      Fill in the IPv6 header
 202          */
 203         if (np)
 204                 hlimit = np->hop_limit;
 205         if (hlimit < 0)
 206                 hlimit = ip6_dst_hoplimit(dst);
 207
 208         ip6_flow_hdr(hdr, tclass, fl6->flowlabel);
 209
 210         hdr->payload_len = htons(seg_len);
 211         hdr->nexthdr = proto;
 212         hdr->hop_limit = hlimit;
 213
 214         hdr->saddr = fl6->saddr;
 215         hdr->daddr = *first_hop;
 216
 217         skb->protocol = htons(ETH_P_IPV6);
 218         skb->priority = sk->sk_priority;
 219         skb->mark = sk->sk_mark;
 220
 221         mtu = dst_mtu(dst);
 222         if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
 223                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 224                               IPSTATS_MIB_OUT, skb->len);
 225                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 226                                dst->dev, dst_output);
 227         }
 228
 229         skb->dev = dst->dev;
 230         ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
 231         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 232         kfree_skb(skb);
 233         return -EMSGSIZE;
 234 }
 235
 236 EXPORT_SYMBOL(ip6_xmit);
 237
 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 239 {
 240         struct ip6_ra_chain *ra;
 241         struct sock *last = NULL;
 242
 243         read_lock(&ip6_ra_lock);
 244         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 245                 struct sock *sk = ra->sk;
 246                 if (sk && ra->sel == sel &&
 247                     (!sk->sk_bound_dev_if ||
 248                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 249                         if (last) {
 250                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 251                                 if (skb2)
 252                                         rawv6_rcv(last, skb2);
 253                         }
 254                         last = sk;
 255                 }
 256         }
 257
 258         if (last) {
 259                 rawv6_rcv(last, skb);
 260                 read_unlock(&ip6_ra_lock);
 261                 return 1;
 262         }
 263         read_unlock(&ip6_ra_lock);
 264         return 0;
 265 }
 266
 267 static int ip6_forward_proxy_check(struct sk_buff *skb)
 268 {
 269         struct ipv6hdr *hdr = ipv6_hdr(skb);
 270         u8 nexthdr = hdr->nexthdr;
 271         __be16 frag_off;
 272         int offset;
 273
 274         if (ipv6_ext_hdr(nexthdr)) {
 275                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 276                 if (offset < 0)
 277                         return 0;
 278         } else
 279                 offset = sizeof(struct ipv6hdr);
 280
 281         if (nexthdr == IPPROTO_ICMPV6) {
 282                 struct icmp6hdr *icmp6;
 283
 284                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 285                                          offset + 1 - skb->data)))
 286                         return 0;
 287
 288                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 289
 290                 switch (icmp6->icmp6_type) {
 291                 case NDISC_ROUTER_SOLICITATION:
 292                 case NDISC_ROUTER_ADVERTISEMENT:
 293                 case NDISC_NEIGHBOUR_SOLICITATION:
 294                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 295                 case NDISC_REDIRECT:
 296                         /* For reaction involving unicast neighbor discovery
 297                          * message destined to the proxied address, pass it to
 298                          * input function.
 299                          */
 300                         return 1;
 301                 default:
 302                         break;
 303                 }
 304         }
 305
 306         /*
 307          * The proxying router can't forward traffic sent to a link-local
 308          * address, so signal the sender and discard the packet. This
 309          * behavior is clarified by the MIPv6 specification.
 310          */
 311         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 312                 dst_link_failure(skb);
 313                 return -1;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static inline int ip6_forward_finish(struct sk_buff *skb)
 320 {
 321         return dst_output(skb);
 322 }
 323
 324 int ip6_forward(struct sk_buff *skb)
 325 {
 326         struct dst_entry *dst = skb_dst(skb);
 327         struct ipv6hdr *hdr = ipv6_hdr(skb);
 328         struct inet6_skb_parm *opt = IP6CB(skb);
 329         struct net *net = dev_net(dst->dev);
 330         u32 mtu;
 331
 332         if (net->ipv6.devconf_all->forwarding == 0)
 333                 goto error;
 334
 335         if (skb_warn_if_lro(skb))
 336                 goto drop;
 337
 338         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 339                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 340                                  IPSTATS_MIB_INDISCARDS);
 341                 goto drop;
 342         }
 343
 344         if (skb->pkt_type != PACKET_HOST)
 345                 goto drop;
 346
 347         skb_forward_csum(skb);
 348
 349         /*
 350          *      We DO NOT make any processing on
 351          *      RA packets, pushing them to user level AS IS
 352          *      without ane WARRANTY that application will be able
 353          *      to interpret them. The reason is that we
 354          *      cannot make anything clever here.
 355          *
 356          *      We are not end-node, so that if packet contains
 357          *      AH/ESP, we cannot make anything.
 358          *      Defragmentation also would be mistake, RA packets
 359          *      cannot be fragmented, because there is no warranty
 360          *      that different fragments will go along one path. --ANK
 361          */
 362         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 363                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 364                         return 0;
 365         }
 366
 367         /*
 368          *      check and decrement ttl
 369          */
 370         if (hdr->hop_limit <= 1) {
 371                 /* Force OUTPUT device used as source address */
 372                 skb->dev = dst->dev;
 373                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 374                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 375                                  IPSTATS_MIB_INHDRERRORS);
 376
 377                 kfree_skb(skb);
 378                 return -ETIMEDOUT;
 379         }
 380
 381         /* XXX: idev->cnf.proxy_ndp? */
 382         if (net->ipv6.devconf_all->proxy_ndp &&
 383             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 384                 int proxied = ip6_forward_proxy_check(skb);
 385                 if (proxied > 0)
 386                         return ip6_input(skb);
 387                 else if (proxied < 0) {
 388                         IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 389                                          IPSTATS_MIB_INDISCARDS);
 390                         goto drop;
 391                 }
 392         }
 393
 394         if (!xfrm6_route_forward(skb)) {
 395                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 396                                  IPSTATS_MIB_INDISCARDS);
 397                 goto drop;
 398         }
 399         dst = skb_dst(skb);
 400
 401         /* IPv6 specs say nothing about it, but it is clear that we cannot
 402            send redirects to source routed frames.
 403            We don't send redirects to frames decapsulated from IPsec.
 404          */
 405         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 406                 struct in6_addr *target = NULL;
 407                 struct inet_peer *peer;
 408                 struct rt6_info *rt;
 409
 410                 /*
 411                  *      incoming and outgoing devices are the same
 412                  *      send a redirect.
 413                  */
 414
 415                 rt = (struct rt6_info *) dst;
 416                 if (rt->rt6i_flags & RTF_GATEWAY)
 417                         target = &rt->rt6i_gateway;
 418                 else
 419                         target = &hdr->daddr;
 420
 421                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 422
 423                 /* Limit redirects both by destination (here)
 424                    and by source (inside ndisc_send_redirect)
 425                  */
 426                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 427                         ndisc_send_redirect(skb, target);
 428                 if (peer)
 429                         inet_putpeer(peer);
 430         } else {
 431                 int addrtype = ipv6_addr_type(&hdr->saddr);
 432
 433                 /* This check is security critical. */
 434                 if (addrtype == IPV6_ADDR_ANY ||
 435                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 436                         goto error;
 437                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 438                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 439                                     ICMPV6_NOT_NEIGHBOUR, 0);
 440                         goto error;
 441                 }
 442         }
 443
 444         mtu = dst_mtu(dst);
 445         if (mtu < IPV6_MIN_MTU)
 446                 mtu = IPV6_MIN_MTU;
 447
 448         if ((!skb->local_df && skb->len > mtu && !skb_is_gso(skb)) ||
 449             (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)) {
 450                 /* Again, force OUTPUT device used as source address */
 451                 skb->dev = dst->dev;
 452                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 453                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 454                                  IPSTATS_MIB_INTOOBIGERRORS);
 455                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 456                                  IPSTATS_MIB_FRAGFAILS);
 457                 kfree_skb(skb);
 458                 return -EMSGSIZE;
 459         }
 460
 461         if (skb_cow(skb, dst->dev->hard_header_len)) {
 462                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 463                                  IPSTATS_MIB_OUTDISCARDS);
 464                 goto drop;
 465         }
 466
 467         hdr = ipv6_hdr(skb);
 468
 469         /* Mangling hops number delayed to point after skb COW */
 470
 471         hdr->hop_limit--;
 472
 473         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 474         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 475         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 476                        ip6_forward_finish);
 477
 478 error:
 479         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 480 drop:
 481         kfree_skb(skb);
 482         return -EINVAL;
 483 }
 484
 485 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 486 {
 487         to->pkt_type = from->pkt_type;
 488         to->priority = from->priority;
 489         to->protocol = from->protocol;
 490         skb_dst_drop(to);
 491         skb_dst_set(to, dst_clone(skb_dst(from)));
 492         to->dev = from->dev;
 493         to->mark = from->mark;
 494
 495 #ifdef CONFIG_NET_SCHED
 496         to->tc_index = from->tc_index;
 497 #endif
 498         nf_copy(to, from);
 499 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 500         to->nf_trace = from->nf_trace;
 501 #endif
 502         skb_copy_secmark(to, from);
 503 }
 504
 505 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 506 {
 507         struct sk_buff *frag;
 508         struct rt6_info *rt = (struct rt6_info*)skb_dst(skb);
 509         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 510         struct ipv6hdr *tmp_hdr;
 511         struct frag_hdr *fh;
 512         unsigned int mtu, hlen, left, len;
 513         int hroom, troom;
 514         __be32 frag_id = 0;
 515         int ptr, offset = 0, err=0;
 516         u8 *prevhdr, nexthdr = 0;
 517         struct net *net = dev_net(skb_dst(skb)->dev);
 518
 519         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 520         nexthdr = *prevhdr;
 521
 522         mtu = ip6_skb_dst_mtu(skb);
 523
 524         /* We must not fragment if the socket is set to force MTU discovery
 525          * or if the skb it not generated by a local socket.
 526          */
 527         if (unlikely(!skb->local_df && skb->len > mtu) ||
 528                      (IP6CB(skb)->frag_max_size &&
 529                       IP6CB(skb)->frag_max_size > mtu)) {
 530                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 531                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 532
 533                 skb->dev = skb_dst(skb)->dev;
 534                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 535                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 536                               IPSTATS_MIB_FRAGFAILS);
 537                 kfree_skb(skb);
 538                 return -EMSGSIZE;
 539         }
 540
 541         if (np && np->frag_size < mtu) {
 542                 if (np->frag_size)
 543                         mtu = np->frag_size;
 544         }
 545         mtu -= hlen + sizeof(struct frag_hdr);
 546
 547         if (skb_has_frag_list(skb)) {
 548                 int first_len = skb_pagelen(skb);
 549                 struct sk_buff *frag2;
 550
 551                 if (first_len - hlen > mtu ||
 552                     ((first_len - hlen) & 7) ||
 553                     skb_cloned(skb))
 554                         goto slow_path;
 555
 556                 skb_walk_frags(skb, frag) {
 557                         /* Correct geometry. */
 558                         if (frag->len > mtu ||
 559                             ((frag->len & 7) && frag->next) ||
 560                             skb_headroom(frag) < hlen)
 561                                 goto slow_path_clean;
 562
 563                         /* Partially cloned skb? */
 564                         if (skb_shared(frag))
 565                                 goto slow_path_clean;
 566
 567                         BUG_ON(frag->sk);
 568                         if (skb->sk) {
 569                                 frag->sk = skb->sk;
 570                                 frag->destructor = sock_wfree;
 571                         }
 572                         skb->truesize -= frag->truesize;
 573                 }
 574
 575                 err = 0;
 576                 offset = 0;
 577                 frag = skb_shinfo(skb)->frag_list;
 578                 skb_frag_list_init(skb);
 579                 /* BUILD HEADER */
 580
 581                 *prevhdr = NEXTHDR_FRAGMENT;
 582                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 583                 if (!tmp_hdr) {
 584                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 585                                       IPSTATS_MIB_FRAGFAILS);
 586                         return -ENOMEM;
 587                 }
 588
 589                 __skb_pull(skb, hlen);
 590                 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
 591                 __skb_push(skb, hlen);
 592                 skb_reset_network_header(skb);
 593                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 594
 595                 ipv6_select_ident(fh, rt);
 596                 fh->nexthdr = nexthdr;
 597                 fh->reserved = 0;
 598                 fh->frag_off = htons(IP6_MF);
 599                 frag_id = fh->identification;
 600
 601                 first_len = skb_pagelen(skb);
 602                 skb->data_len = first_len - skb_headlen(skb);
 603                 skb->len = first_len;
 604                 ipv6_hdr(skb)->payload_len = htons(first_len -
 605                                                    sizeof(struct ipv6hdr));
 606
 607                 dst_hold(&rt->dst);
 608
 609                 for (;;) {
 610                         /* Prepare header of the next frame,
 611                          * before previous one went down. */
 612                         if (frag) {
 613                                 frag->ip_summed = CHECKSUM_NONE;
 614                                 skb_reset_transport_header(frag);
 615                                 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 616                                 __skb_push(frag, hlen);
 617                                 skb_reset_network_header(frag);
 618                                 memcpy(skb_network_header(frag), tmp_hdr,
 619                                        hlen);
 620                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 621                                 fh->nexthdr = nexthdr;
 622                                 fh->reserved = 0;
 623                                 fh->frag_off = htons(offset);
 624                                 if (frag->next != NULL)
 625                                         fh->frag_off |= htons(IP6_MF);
 626                                 fh->identification = frag_id;
 627                                 ipv6_hdr(frag)->payload_len =
 628                                                 htons(frag->len -
 629                                                       sizeof(struct ipv6hdr));
 630                                 ip6_copy_metadata(frag, skb);
 631                         }
 632
 633                         err = output(skb);
 634                         if(!err)
 635                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 636                                               IPSTATS_MIB_FRAGCREATES);
 637
 638                         if (err || !frag)
 639                                 break;
 640
 641                         skb = frag;
 642                         frag = skb->next;
 643                         skb->next = NULL;
 644                 }
 645
 646                 kfree(tmp_hdr);
 647
 648                 if (err == 0) {
 649                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 650                                       IPSTATS_MIB_FRAGOKS);
 651                         ip6_rt_put(rt);
 652                         return 0;
 653                 }
 654
 655                 while (frag) {
 656                         skb = frag->next;
 657                         kfree_skb(frag);
 658                         frag = skb;
 659                 }
 660
 661                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 662                               IPSTATS_MIB_FRAGFAILS);
 663                 ip6_rt_put(rt);
 664                 return err;
 665
 666 slow_path_clean:
 667                 skb_walk_frags(skb, frag2) {
 668                         if (frag2 == frag)
 669                                 break;
 670                         frag2->sk = NULL;
 671                         frag2->destructor = NULL;
 672                         skb->truesize += frag2->truesize;
 673                 }
 674         }
 675
 676 slow_path:
 677         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 678             skb_checksum_help(skb))
 679                 goto fail;
 680
 681         left = skb->len - hlen;         /* Space per frame */
 682         ptr = hlen;                     /* Where to start from */
 683
 684         /*
 685          *      Fragment the datagram.
 686          */
 687
 688         *prevhdr = NEXTHDR_FRAGMENT;
 689         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 690         troom = rt->dst.dev->needed_tailroom;
 691
 692         /*
 693          *      Keep copying data until we run out.
 694          */
 695         while(left > 0) {
 696                 len = left;
 697                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 698                 if (len > mtu)
 699                         len = mtu;
 700                 /* IF: we are not sending up to and including the packet end
 701                    then align the next start on an eight byte boundary */
 702                 if (len < left) {
 703                         len &= ~7;
 704                 }
 705                 /*
 706                  *      Allocate buffer.
 707                  */
 708
 709                 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 710                                       hroom + troom, GFP_ATOMIC)) == NULL) {
 711                         NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 712                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 713                                       IPSTATS_MIB_FRAGFAILS);
 714                         err = -ENOMEM;
 715                         goto fail;
 716                 }
 717
 718                 /*
 719                  *      Set up data on packet
 720                  */
 721
 722                 ip6_copy_metadata(frag, skb);
 723                 skb_reserve(frag, hroom);
 724                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 725                 skb_reset_network_header(frag);
 726                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 727                 frag->transport_header = (frag->network_header + hlen +
 728                                           sizeof(struct frag_hdr));
 729
 730                 /*
 731                  *      Charge the memory for the fragment to any owner
 732                  *      it might possess
 733                  */
 734                 if (skb->sk)
 735                         skb_set_owner_w(frag, skb->sk);
 736
 737                 /*
 738                  *      Copy the packet header into the new buffer.
 739                  */
 740                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 741
 742                 /*
 743                  *      Build fragment header.
 744                  */
 745                 fh->nexthdr = nexthdr;
 746                 fh->reserved = 0;
 747                 if (!frag_id) {
 748                         ipv6_select_ident(fh, rt);
 749                         frag_id = fh->identification;
 750                 } else
 751                         fh->identification = frag_id;
 752
 753                 /*
 754                  *      Copy a block of the IP datagram.
 755                  */
 756                 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
 757                         BUG();
 758                 left -= len;
 759
 760                 fh->frag_off = htons(offset);
 761                 if (left > 0)
 762                         fh->frag_off |= htons(IP6_MF);
 763                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 764                                                     sizeof(struct ipv6hdr));
 765
 766                 ptr += len;
 767                 offset += len;
 768
 769                 /*
 770                  *      Put this fragment into the sending queue.
 771                  */
 772                 err = output(frag);
 773                 if (err)
 774                         goto fail;
 775
 776                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 777                               IPSTATS_MIB_FRAGCREATES);
 778         }
 779         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 780                       IPSTATS_MIB_FRAGOKS);
 781         consume_skb(skb);
 782         return err;
 783
 784 fail:
 785         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 786                       IPSTATS_MIB_FRAGFAILS);
 787         kfree_skb(skb);
 788         return err;
 789 }
 790
 791 static inline int ip6_rt_check(const struct rt6key *rt_key,
 792                                const struct in6_addr *fl_addr,
 793                                const struct in6_addr *addr_cache)
 794 {
 795         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 796                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 797 }
 798
 799 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 800                                           struct dst_entry *dst,
 801                                           const struct flowi6 *fl6)
 802 {
 803         struct ipv6_pinfo *np = inet6_sk(sk);
 804         struct rt6_info *rt;
 805
 806         if (!dst)
 807                 goto out;
 808
 809         if (dst->ops->family != AF_INET6) {
 810                 dst_release(dst);
 811                 return NULL;
 812         }
 813
 814         rt = (struct rt6_info *)dst;
 815         /* Yes, checking route validity in not connected
 816          * case is not very simple. Take into account,
 817          * that we do not support routing by source, TOS,
 818          * and MSG_DONTROUTE            --ANK (980726)
 819          *
 820          * 1. ip6_rt_check(): If route was host route,
 821          *    check that cached destination is current.
 822          *    If it is network route, we still may
 823          *    check its validity using saved pointer
 824          *    to the last used address: daddr_cache.
 825          *    We do not want to save whole address now,
 826          *    (because main consumer of this service
 827          *    is tcp, which has not this problem),
 828          *    so that the last trick works only on connected
 829          *    sockets.
 830          * 2. oif also should be the same.
 831          */
 832         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 833 #ifdef CONFIG_IPV6_SUBTREES
 834             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 835 #endif
 836             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 837                 dst_release(dst);
 838                 dst = NULL;
 839         }
 840
 841 out:
 842         return dst;
 843 }
 844
 845 static int ip6_dst_lookup_tail(struct sock *sk,
 846                                struct dst_entry **dst, struct flowi6 *fl6)
 847 {
 848         struct net *net = sock_net(sk);
 849 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 850         struct neighbour *n;
 851         struct rt6_info *rt;
 852 #endif
 853         int err;
 854
 855         if (*dst == NULL)
 856                 *dst = ip6_route_output(net, sk, fl6);
 857
 858         if ((err = (*dst)->error))
 859                 goto out_err_release;
 860
 861         if (ipv6_addr_any(&fl6->saddr)) {
 862                 struct rt6_info *rt = (struct rt6_info *) *dst;
 863                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 864                                           sk ? inet6_sk(sk)->srcprefs : 0,
 865                                           &fl6->saddr);
 866                 if (err)
 867                         goto out_err_release;
 868         }
 869
 870 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 871         /*
 872          * Here if the dst entry we've looked up
 873          * has a neighbour entry that is in the INCOMPLETE
 874          * state and the src address from the flow is
 875          * marked as OPTIMISTIC, we release the found
 876          * dst entry and replace it instead with the
 877          * dst entry of the nexthop router
 878          */
 879         rt = (struct rt6_info *) *dst;
 880         rcu_read_lock_bh();
 881         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
 882         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 883         rcu_read_unlock_bh();
 884
 885         if (err) {
 886                 struct inet6_ifaddr *ifp;
 887                 struct flowi6 fl_gw6;
 888                 int redirect;
 889
 890                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 891                                       (*dst)->dev, 1);
 892
 893                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 894                 if (ifp)
 895                         in6_ifa_put(ifp);
 896
 897                 if (redirect) {
 898                         /*
 899                          * We need to get the dst entry for the
 900                          * default router instead
 901                          */
 902                         dst_release(*dst);
 903                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 904                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 905                         *dst = ip6_route_output(net, sk, &fl_gw6);
 906                         if ((err = (*dst)->error))
 907                                 goto out_err_release;
 908                 }
 909         }
 910 #endif
 911
 912         return 0;
 913
 914 out_err_release:
 915         if (err == -ENETUNREACH)
 916                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 917         dst_release(*dst);
 918         *dst = NULL;
 919         return err;
 920 }
 921
 922 /**
 923  *      ip6_dst_lookup - perform route lookup on flow
 924  *      @sk: socket which provides route info
 925  *      @dst: pointer to dst_entry * for result
 926  *      @fl6: flow to lookup
 927  *
 928  *      This function performs a route lookup on the given flow.
 929  *
 930  *      It returns zero on success, or a standard errno code on error.
 931  */
 932 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 933 {
 934         *dst = NULL;
 935         return ip6_dst_lookup_tail(sk, dst, fl6);
 936 }
 937 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 938
 939 /**
 940  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 941  *      @sk: socket which provides route info
 942  *      @fl6: flow to lookup
 943  *      @final_dst: final destination address for ipsec lookup
 944  *      @can_sleep: we are in a sleepable context
 945  *
 946  *      This function performs a route lookup on the given flow.
 947  *
 948  *      It returns a valid dst pointer on success, or a pointer encoded
 949  *      error code.
 950  */
 951 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 952                                       const struct in6_addr *final_dst,
 953                                       bool can_sleep)
 954 {
 955         struct dst_entry *dst = NULL;
 956         int err;
 957
 958         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 959         if (err)
 960                 return ERR_PTR(err);
 961         if (final_dst)
 962                 fl6->daddr = *final_dst;
 963         if (can_sleep)
 964                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
 965
 966         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
 967 }
 968 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 969
 970 /**
 971  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
 972  *      @sk: socket which provides the dst cache and route info
 973  *      @fl6: flow to lookup
 974  *      @final_dst: final destination address for ipsec lookup
 975  *      @can_sleep: we are in a sleepable context
 976  *
 977  *      This function performs a route lookup on the given flow with the
 978  *      possibility of using the cached route in the socket if it is valid.
 979  *      It will take the socket dst lock when operating on the dst cache.
 980  *      As a result, this function can only be used in process context.
 981  *
 982  *      It returns a valid dst pointer on success, or a pointer encoded
 983  *      error code.
 984  */
 985 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 986                                          const struct in6_addr *final_dst,
 987                                          bool can_sleep)
 988 {
 989         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
 990         int err;
 991
 992         dst = ip6_sk_dst_check(sk, dst, fl6);
 993
 994         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 995         if (err)
 996                 return ERR_PTR(err);
 997         if (final_dst)
 998                 fl6->daddr = *final_dst;
 999         if (can_sleep)
1000                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
1001
1002         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1003 }
1004 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1005
1006 static inline int ip6_ufo_append_data(struct sock *sk,
1007                         int getfrag(void *from, char *to, int offset, int len,
1008                         int odd, struct sk_buff *skb),
1009                         void *from, int length, int hh_len, int fragheaderlen,
1010                         int transhdrlen, int mtu,unsigned int flags,
1011                         struct rt6_info *rt)
1012
1013 {
1014         struct sk_buff *skb;
1015         struct frag_hdr fhdr;
1016         int err;
1017
1018         /* There is support for UDP large send offload by network
1019          * device, so create one single skb packet containing complete
1020          * udp datagram
1021          */
1022         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1023                 skb = sock_alloc_send_skb(sk,
1024                         hh_len + fragheaderlen + transhdrlen + 20,
1025                         (flags & MSG_DONTWAIT), &err);
1026                 if (skb == NULL)
1027                         return err;
1028
1029                 /* reserve space for Hardware header */
1030                 skb_reserve(skb, hh_len);
1031
1032                 /* create space for UDP/IP header */
1033                 skb_put(skb,fragheaderlen + transhdrlen);
1034
1035                 /* initialize network header pointer */
1036                 skb_reset_network_header(skb);
1037
1038                 /* initialize protocol header pointer */
1039                 skb->transport_header = skb->network_header + fragheaderlen;
1040
1041                 skb->protocol = htons(ETH_P_IPV6);
1042                 skb->csum = 0;
1043
1044                 __skb_queue_tail(&sk->sk_write_queue, skb);
1045         } else if (skb_is_gso(skb)) {
1046                 goto append;
1047         }
1048
1049         skb->ip_summed = CHECKSUM_PARTIAL;
1050         /* Specify the length of each IPv6 datagram fragment.
1051          * It has to be a multiple of 8.
1052          */
1053         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1054                                      sizeof(struct frag_hdr)) & ~7;
1055         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1056         ipv6_select_ident(&fhdr, rt);
1057         skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1058
1059 append:
1060         return skb_append_datato_frags(sk, skb, getfrag, from,
1061                                        (length - transhdrlen));
1062 }
1063
1064 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1065                                                gfp_t gfp)
1066 {
1067         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1068 }
1069
1070 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1071                                                 gfp_t gfp)
1072 {
1073         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1074 }
1075
1076 static void ip6_append_data_mtu(unsigned int *mtu,
1077                                 int *maxfraglen,
1078                                 unsigned int fragheaderlen,
1079                                 struct sk_buff *skb,
1080                                 struct rt6_info *rt,
1081                                 bool pmtuprobe)
1082 {
1083         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1084                 if (skb == NULL) {
1085                         /* first fragment, reserve header_len */
1086                         *mtu = *mtu - rt->dst.header_len;
1087
1088                 } else {
1089                         /*
1090                          * this fragment is not first, the headers
1091                          * space is regarded as data space.
1092                          */
1093                         *mtu = min(*mtu, pmtuprobe ?
1094                                    rt->dst.dev->mtu :
1095                                    dst_mtu(rt->dst.path));
1096                 }
1097                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1098                               + fragheaderlen - sizeof(struct frag_hdr);
1099         }
1100 }
1101
1102 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1103         int offset, int len, int odd, struct sk_buff *skb),
1104         void *from, int length, int transhdrlen,
1105         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1106         struct rt6_info *rt, unsigned int flags, int dontfrag)
1107 {
1108         struct inet_sock *inet = inet_sk(sk);
1109         struct ipv6_pinfo *np = inet6_sk(sk);
1110         struct inet_cork *cork;
1111         struct sk_buff *skb, *skb_prev = NULL;
1112         unsigned int maxfraglen, fragheaderlen, mtu;
1113         int exthdrlen;
1114         int dst_exthdrlen;
1115         int hh_len;
1116         int copy;
1117         int err;
1118         int offset = 0;
1119         __u8 tx_flags = 0;
1120
1121         if (flags&MSG_PROBE)
1122                 return 0;
1123         cork = &inet->cork.base;
1124         if (skb_queue_empty(&sk->sk_write_queue)) {
1125                 /*
1126                  * setup for corking
1127                  */
1128                 if (opt) {
1129                         if (WARN_ON(np->cork.opt))
1130                                 return -EINVAL;
1131
1132                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1133                         if (unlikely(np->cork.opt == NULL))
1134                                 return -ENOBUFS;
1135
1136                         np->cork.opt->tot_len = opt->tot_len;
1137                         np->cork.opt->opt_flen = opt->opt_flen;
1138                         np->cork.opt->opt_nflen = opt->opt_nflen;
1139
1140                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1141                                                             sk->sk_allocation);
1142                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1143                                 return -ENOBUFS;
1144
1145                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1146                                                             sk->sk_allocation);
1147                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1148                                 return -ENOBUFS;
1149
1150                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1151                                                            sk->sk_allocation);
1152                         if (opt->hopopt && !np->cork.opt->hopopt)
1153                                 return -ENOBUFS;
1154
1155                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1156                                                             sk->sk_allocation);
1157                         if (opt->srcrt && !np->cork.opt->srcrt)
1158                                 return -ENOBUFS;
1159
1160                         /* need source address above miyazawa*/
1161                 }
1162                 dst_hold(&rt->dst);
1163                 cork->dst = &rt->dst;
1164                 inet->cork.fl.u.ip6 = *fl6;
1165                 np->cork.hop_limit = hlimit;
1166                 np->cork.tclass = tclass;
1167                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1168                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1169                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1170                 else
1171                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1172                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1173                 if (np->frag_size < mtu) {
1174                         if (np->frag_size)
1175                                 mtu = np->frag_size;
1176                 }
1177                 cork->fragsize = mtu;
1178                 if (dst_allfrag(rt->dst.path))
1179                         cork->flags |= IPCORK_ALLFRAG;
1180                 cork->length = 0;
1181                 exthdrlen = (opt ? opt->opt_flen : 0);
1182                 length += exthdrlen;
1183                 transhdrlen += exthdrlen;
1184                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1185         } else {
1186                 rt = (struct rt6_info *)cork->dst;
1187                 fl6 = &inet->cork.fl.u.ip6;
1188                 opt = np->cork.opt;
1189                 transhdrlen = 0;
1190                 exthdrlen = 0;
1191                 dst_exthdrlen = 0;
1192                 mtu = cork->fragsize;
1193         }
1194
1195         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1196
1197         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1198                         (opt ? opt->opt_nflen : 0);
1199         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1200
1201         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1202                 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1203                         ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen);
1204                         return -EMSGSIZE;
1205                 }
1206         }
1207
1208         /* For UDP, check if TX timestamp is enabled */
1209         if (sk->sk_type == SOCK_DGRAM)
1210                 sock_tx_timestamp(sk, &tx_flags);
1211
1212         /*
1213          * Let's try using as much space as possible.
1214          * Use MTU if total length of the message fits into the MTU.
1215          * Otherwise, we need to reserve fragment header and
1216          * fragment alignment (= 8-15 octects, in total).
1217          *
1218          * Note that we may need to "move" the data from the tail of
1219          * of the buffer to the new fragment when we split
1220          * the message.
1221          *
1222          * FIXME: It may be fragmented into multiple chunks
1223          *        at once if non-fragmentable extension headers
1224          *        are too large.
1225          * --yoshfuji
1226          */
1227
1228         if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP ||
1229                                            sk->sk_protocol == IPPROTO_RAW)) {
1230                 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
1231                 return -EMSGSIZE;
1232         }
1233
1234         skb = skb_peek_tail(&sk->sk_write_queue);
1235         cork->length += length;
1236         if (((length > mtu) ||
1237              (skb && skb_is_gso(skb))) &&
1238             (sk->sk_protocol == IPPROTO_UDP) &&
1239             (rt->dst.dev->features & NETIF_F_UFO)) {
1240                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1241                                           hh_len, fragheaderlen,
1242                                           transhdrlen, mtu, flags, rt);
1243                 if (err)
1244                         goto error;
1245                 return 0;
1246         }
1247
1248         if (!skb)
1249                 goto alloc_new_skb;
1250
1251         while (length > 0) {
1252                 /* Check if the remaining data fits into current packet. */
1253                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1254                 if (copy < length)
1255                         copy = maxfraglen - skb->len;
1256
1257                 if (copy <= 0) {
1258                         char *data;
1259                         unsigned int datalen;
1260                         unsigned int fraglen;
1261                         unsigned int fraggap;
1262                         unsigned int alloclen;
1263 alloc_new_skb:
1264                         /* There's no room in the current skb */
1265                         if (skb)
1266                                 fraggap = skb->len - maxfraglen;
1267                         else
1268                                 fraggap = 0;
1269                         /* update mtu and maxfraglen if necessary */
1270                         if (skb == NULL || skb_prev == NULL)
1271                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1272                                                     fragheaderlen, skb, rt,
1273                                                     np->pmtudisc ==
1274                                                     IPV6_PMTUDISC_PROBE);
1275
1276                         skb_prev = skb;
1277
1278                         /*
1279                          * If remaining data exceeds the mtu,
1280                          * we know we need more fragment(s).
1281                          */
1282                         datalen = length + fraggap;
1283
1284                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1285                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1286                         if ((flags & MSG_MORE) &&
1287                             !(rt->dst.dev->features&NETIF_F_SG))
1288                                 alloclen = mtu;
1289                         else
1290                                 alloclen = datalen + fragheaderlen;
1291
1292                         alloclen += dst_exthdrlen;
1293
1294                         if (datalen != length + fraggap) {
1295                                 /*
1296                                  * this is not the last fragment, the trailer
1297                                  * space is regarded as data space.
1298                                  */
1299                                 datalen += rt->dst.trailer_len;
1300                         }
1301
1302                         alloclen += rt->dst.trailer_len;
1303                         fraglen = datalen + fragheaderlen;
1304
1305                         /*
1306                          * We just reserve space for fragment header.
1307                          * Note: this may be overallocation if the message
1308                          * (without MSG_MORE) fits into the MTU.
1309                          */
1310                         alloclen += sizeof(struct frag_hdr);
1311
1312                         if (transhdrlen) {
1313                                 skb = sock_alloc_send_skb(sk,
1314                                                 alloclen + hh_len,
1315                                                 (flags & MSG_DONTWAIT), &err);
1316                         } else {
1317                                 skb = NULL;
1318                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1319                                     2 * sk->sk_sndbuf)
1320                                         skb = sock_wmalloc(sk,
1321                                                            alloclen + hh_len, 1,
1322                                                            sk->sk_allocation);
1323                                 if (unlikely(skb == NULL))
1324                                         err = -ENOBUFS;
1325                                 else {
1326                                         /* Only the initial fragment
1327                                          * is time stamped.
1328                                          */
1329                                         tx_flags = 0;
1330                                 }
1331                         }
1332                         if (skb == NULL)
1333                                 goto error;
1334                         /*
1335                          *      Fill in the control structures
1336                          */
1337                         skb->protocol = htons(ETH_P_IPV6);
1338                         skb->ip_summed = CHECKSUM_NONE;
1339                         skb->csum = 0;
1340                         /* reserve for fragmentation and ipsec header */
1341                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1342                                     dst_exthdrlen);
1343
1344                         if (sk->sk_type == SOCK_DGRAM)
1345                                 skb_shinfo(skb)->tx_flags = tx_flags;
1346
1347                         /*
1348                          *      Find where to start putting bytes
1349                          */
1350                         data = skb_put(skb, fraglen);
1351                         skb_set_network_header(skb, exthdrlen);
1352                         data += fragheaderlen;
1353                         skb->transport_header = (skb->network_header +
1354                                                  fragheaderlen);
1355                         if (fraggap) {
1356                                 skb->csum = skb_copy_and_csum_bits(
1357                                         skb_prev, maxfraglen,
1358                                         data + transhdrlen, fraggap, 0);
1359                                 skb_prev->csum = csum_sub(skb_prev->csum,
1360                                                           skb->csum);
1361                                 data += fraggap;
1362                                 pskb_trim_unique(skb_prev, maxfraglen);
1363                         }
1364                         copy = datalen - transhdrlen - fraggap;
1365
1366                         if (copy < 0) {
1367                                 err = -EINVAL;
1368                                 kfree_skb(skb);
1369                                 goto error;
1370                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1371                                 err = -EFAULT;
1372                                 kfree_skb(skb);
1373                                 goto error;
1374                         }
1375
1376                         offset += copy;
1377                         length -= datalen - fraggap;
1378                         transhdrlen = 0;
1379                         exthdrlen = 0;
1380                         dst_exthdrlen = 0;
1381
1382                         /*
1383                          * Put the packet on the pending queue
1384                          */
1385                         __skb_queue_tail(&sk->sk_write_queue, skb);
1386                         continue;
1387                 }
1388
1389                 if (copy > length)
1390                         copy = length;
1391
1392                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1393                         unsigned int off;
1394
1395                         off = skb->len;
1396                         if (getfrag(from, skb_put(skb, copy),
1397                                                 offset, copy, off, skb) < 0) {
1398                                 __skb_trim(skb, off);
1399                                 err = -EFAULT;
1400                                 goto error;
1401                         }
1402                 } else {
1403                         int i = skb_shinfo(skb)->nr_frags;
1404                         struct page_frag *pfrag = sk_page_frag(sk);
1405
1406                         err = -ENOMEM;
1407                         if (!sk_page_frag_refill(sk, pfrag))
1408                                 goto error;
1409
1410                         if (!skb_can_coalesce(skb, i, pfrag->page,
1411                                               pfrag->offset)) {
1412                                 err = -EMSGSIZE;
1413                                 if (i == MAX_SKB_FRAGS)
1414                                         goto error;
1415
1416                                 __skb_fill_page_desc(skb, i, pfrag->page,
1417                                                      pfrag->offset, 0);
1418                                 skb_shinfo(skb)->nr_frags = ++i;
1419                                 get_page(pfrag->page);
1420                         }
1421                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1422                         if (getfrag(from,
1423                                     page_address(pfrag->page) + pfrag->offset,
1424                                     offset, copy, skb->len, skb) < 0)
1425                                 goto error_efault;
1426
1427                         pfrag->offset += copy;
1428                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1429                         skb->len += copy;
1430                         skb->data_len += copy;
1431                         skb->truesize += copy;
1432                         atomic_add(copy, &sk->sk_wmem_alloc);
1433                 }
1434                 offset += copy;
1435                 length -= copy;
1436         }
1437
1438         return 0;
1439
1440 error_efault:
1441         err = -EFAULT;
1442 error:
1443         cork->length -= length;
1444         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1445         return err;
1446 }
1447 EXPORT_SYMBOL_GPL(ip6_append_data);
1448
1449 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1450 {
1451         if (np->cork.opt) {
1452                 kfree(np->cork.opt->dst0opt);
1453                 kfree(np->cork.opt->dst1opt);
1454                 kfree(np->cork.opt->hopopt);
1455                 kfree(np->cork.opt->srcrt);
1456                 kfree(np->cork.opt);
1457                 np->cork.opt = NULL;
1458         }
1459
1460         if (inet->cork.base.dst) {
1461                 dst_release(inet->cork.base.dst);
1462                 inet->cork.base.dst = NULL;
1463                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1464         }
1465         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1466 }
1467
1468 int ip6_push_pending_frames(struct sock *sk)
1469 {
1470         struct sk_buff *skb, *tmp_skb;
1471         struct sk_buff **tail_skb;
1472         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1473         struct inet_sock *inet = inet_sk(sk);
1474         struct ipv6_pinfo *np = inet6_sk(sk);
1475         struct net *net = sock_net(sk);
1476         struct ipv6hdr *hdr;
1477         struct ipv6_txoptions *opt = np->cork.opt;
1478         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1479         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1480         unsigned char proto = fl6->flowi6_proto;
1481         int err = 0;
1482
1483         if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1484                 goto out;
1485         tail_skb = &(skb_shinfo(skb)->frag_list);
1486
1487         /* move skb->data to ip header from ext header */
1488         if (skb->data < skb_network_header(skb))
1489                 __skb_pull(skb, skb_network_offset(skb));
1490         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1491                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1492                 *tail_skb = tmp_skb;
1493                 tail_skb = &(tmp_skb->next);
1494                 skb->len += tmp_skb->len;
1495                 skb->data_len += tmp_skb->len;
1496                 skb->truesize += tmp_skb->truesize;
1497                 tmp_skb->destructor = NULL;
1498                 tmp_skb->sk = NULL;
1499         }
1500
1501         /* Allow local fragmentation. */
1502         if (np->pmtudisc < IPV6_PMTUDISC_DO)
1503                 skb->local_df = 1;
1504
1505         *final_dst = fl6->daddr;
1506         __skb_pull(skb, skb_network_header_len(skb));
1507         if (opt && opt->opt_flen)
1508                 ipv6_push_frag_opts(skb, opt, &proto);
1509         if (opt && opt->opt_nflen)
1510                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1511
1512         skb_push(skb, sizeof(struct ipv6hdr));
1513         skb_reset_network_header(skb);
1514         hdr = ipv6_hdr(skb);
1515
1516         ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel);
1517         hdr->hop_limit = np->cork.hop_limit;
1518         hdr->nexthdr = proto;
1519         hdr->saddr = fl6->saddr;
1520         hdr->daddr = *final_dst;
1521
1522         skb->priority = sk->sk_priority;
1523         skb->mark = sk->sk_mark;
1524
1525         skb_dst_set(skb, dst_clone(&rt->dst));
1526         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1527         if (proto == IPPROTO_ICMPV6) {
1528                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1529
1530                 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type);
1531                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
1532         }
1533
1534         err = ip6_local_out(skb);
1535         if (err) {
1536                 if (err > 0)
1537                         err = net_xmit_errno(err);
1538                 if (err)
1539                         goto error;
1540         }
1541
1542 out:
1543         ip6_cork_release(inet, np);
1544         return err;
1545 error:
1546         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1547         goto out;
1548 }
1549 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1550
1551 void ip6_flush_pending_frames(struct sock *sk)
1552 {
1553         struct sk_buff *skb;
1554
1555         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1556                 if (skb_dst(skb))
1557                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1558                                       IPSTATS_MIB_OUTDISCARDS);
1559                 kfree_skb(skb);
1560         }
1561
1562         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1563 }
1564 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);