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 sock *sk, struct sk_buff *skb)
 136 {
 137         struct net_device *dev = skb_dst(skb)->dev;
 138         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(dev_net(dev), idev,
 141                               IPSTATS_MIB_OUTDISCARDS);
 142                 kfree_skb(skb);
 143                 return 0;
 144         }
 145
 146         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
 147                             ip6_finish_output,
 148                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 149 }
 150
 151 /*
 152  *      xmit an sk_buff (used by TCP, SCTP and DCCP)
 153  */
 154
 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 156              struct ipv6_txoptions *opt, int tclass)
 157 {
 158         struct net *net = sock_net(sk);
 159         struct ipv6_pinfo *np = inet6_sk(sk);
 160         struct in6_addr *first_hop = &fl6->daddr;
 161         struct dst_entry *dst = skb_dst(skb);
 162         struct ipv6hdr *hdr;
 163         u8  proto = fl6->flowi6_proto;
 164         int seg_len = skb->len;
 165         int hlimit = -1;
 166         u32 mtu;
 167
 168         if (opt) {
 169                 unsigned int head_room;
 170
 171                 /* First: exthdrs may take lots of space (~8K for now)
 172                    MAX_HEADER is not enough.
 173                  */
 174                 head_room = opt->opt_nflen + opt->opt_flen;
 175                 seg_len += head_room;
 176                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 177
 178                 if (skb_headroom(skb) < head_room) {
 179                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 180                         if (skb2 == NULL) {
 181                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 182                                               IPSTATS_MIB_OUTDISCARDS);
 183                                 kfree_skb(skb);
 184                                 return -ENOBUFS;
 185                         }
 186                         consume_skb(skb);
 187                         skb = skb2;
 188                         skb_set_owner_w(skb, sk);
 189                 }
 190                 if (opt->opt_flen)
 191                         ipv6_push_frag_opts(skb, opt, &proto);
 192                 if (opt->opt_nflen)
 193                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 194         }
 195
 196         skb_push(skb, sizeof(struct ipv6hdr));
 197         skb_reset_network_header(skb);
 198         hdr = ipv6_hdr(skb);
 199
 200         /*
 201          *      Fill in the IPv6 header
 202          */
 203         if (np)
 204                 hlimit = np->hop_limit;
 205         if (hlimit < 0)
 206                 hlimit = ip6_dst_hoplimit(dst);
 207
 208         ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
 209                                                      np->autoflowlabel));
 210
 211         hdr->payload_len = htons(seg_len);
 212         hdr->nexthdr = proto;
 213         hdr->hop_limit = hlimit;
 214
 215         hdr->saddr = fl6->saddr;
 216         hdr->daddr = *first_hop;
 217
 218         skb->protocol = htons(ETH_P_IPV6);
 219         skb->priority = sk->sk_priority;
 220         skb->mark = sk->sk_mark;
 221
 222         mtu = dst_mtu(dst);
 223         if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 224                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 225                               IPSTATS_MIB_OUT, skb->len);
 226                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 227                                dst->dev, dst_output);
 228         }
 229
 230         skb->dev = dst->dev;
 231         ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
 232         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 233         kfree_skb(skb);
 234         return -EMSGSIZE;
 235 }
 236 EXPORT_SYMBOL(ip6_xmit);
 237
 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 239 {
 240         struct ip6_ra_chain *ra;
 241         struct sock *last = NULL;
 242
 243         read_lock(&ip6_ra_lock);
 244         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 245                 struct sock *sk = ra->sk;
 246                 if (sk && ra->sel == sel &&
 247                     (!sk->sk_bound_dev_if ||
 248                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 249                         if (last) {
 250                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 251                                 if (skb2)
 252                                         rawv6_rcv(last, skb2);
 253                         }
 254                         last = sk;
 255                 }
 256         }
 257
 258         if (last) {
 259                 rawv6_rcv(last, skb);
 260                 read_unlock(&ip6_ra_lock);
 261                 return 1;
 262         }
 263         read_unlock(&ip6_ra_lock);
 264         return 0;
 265 }
 266
 267 static int ip6_forward_proxy_check(struct sk_buff *skb)
 268 {
 269         struct ipv6hdr *hdr = ipv6_hdr(skb);
 270         u8 nexthdr = hdr->nexthdr;
 271         __be16 frag_off;
 272         int offset;
 273
 274         if (ipv6_ext_hdr(nexthdr)) {
 275                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 276                 if (offset < 0)
 277                         return 0;
 278         } else
 279                 offset = sizeof(struct ipv6hdr);
 280
 281         if (nexthdr == IPPROTO_ICMPV6) {
 282                 struct icmp6hdr *icmp6;
 283
 284                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 285                                          offset + 1 - skb->data)))
 286                         return 0;
 287
 288                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 289
 290                 switch (icmp6->icmp6_type) {
 291                 case NDISC_ROUTER_SOLICITATION:
 292                 case NDISC_ROUTER_ADVERTISEMENT:
 293                 case NDISC_NEIGHBOUR_SOLICITATION:
 294                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 295                 case NDISC_REDIRECT:
 296                         /* For reaction involving unicast neighbor discovery
 297                          * message destined to the proxied address, pass it to
 298                          * input function.
 299                          */
 300                         return 1;
 301                 default:
 302                         break;
 303                 }
 304         }
 305
 306         /*
 307          * The proxying router can't forward traffic sent to a link-local
 308          * address, so signal the sender and discard the packet. This
 309          * behavior is clarified by the MIPv6 specification.
 310          */
 311         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 312                 dst_link_failure(skb);
 313                 return -1;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static inline int ip6_forward_finish(struct sk_buff *skb)
 320 {
 321         return dst_output(skb);
 322 }
 323
 324 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 325 {
 326         unsigned int mtu;
 327         struct inet6_dev *idev;
 328
 329         if (dst_metric_locked(dst, RTAX_MTU)) {
 330                 mtu = dst_metric_raw(dst, RTAX_MTU);
 331                 if (mtu)
 332                         return mtu;
 333         }
 334
 335         mtu = IPV6_MIN_MTU;
 336         rcu_read_lock();
 337         idev = __in6_dev_get(dst->dev);
 338         if (idev)
 339                 mtu = idev->cnf.mtu6;
 340         rcu_read_unlock();
 341
 342         return mtu;
 343 }
 344
 345 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 346 {
 347         if (skb->len <= mtu)
 348                 return false;
 349
 350         /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
 351         if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
 352                 return true;
 353
 354         if (skb->ignore_df)
 355                 return false;
 356
 357         if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
 358                 return false;
 359
 360         return true;
 361 }
 362
 363 int ip6_forward(struct sk_buff *skb)
 364 {
 365         struct dst_entry *dst = skb_dst(skb);
 366         struct ipv6hdr *hdr = ipv6_hdr(skb);
 367         struct inet6_skb_parm *opt = IP6CB(skb);
 368         struct net *net = dev_net(dst->dev);
 369         u32 mtu;
 370
 371         if (net->ipv6.devconf_all->forwarding == 0)
 372                 goto error;
 373
 374         if (skb->pkt_type != PACKET_HOST)
 375                 goto drop;
 376
 377         if (skb_warn_if_lro(skb))
 378                 goto drop;
 379
 380         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 381                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 382                                  IPSTATS_MIB_INDISCARDS);
 383                 goto drop;
 384         }
 385
 386         skb_forward_csum(skb);
 387
 388         /*
 389          *      We DO NOT make any processing on
 390          *      RA packets, pushing them to user level AS IS
 391          *      without ane WARRANTY that application will be able
 392          *      to interpret them. The reason is that we
 393          *      cannot make anything clever here.
 394          *
 395          *      We are not end-node, so that if packet contains
 396          *      AH/ESP, we cannot make anything.
 397          *      Defragmentation also would be mistake, RA packets
 398          *      cannot be fragmented, because there is no warranty
 399          *      that different fragments will go along one path. --ANK
 400          */
 401         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 402                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 403                         return 0;
 404         }
 405
 406         /*
 407          *      check and decrement ttl
 408          */
 409         if (hdr->hop_limit <= 1) {
 410                 /* Force OUTPUT device used as source address */
 411                 skb->dev = dst->dev;
 412                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 413                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 414                                  IPSTATS_MIB_INHDRERRORS);
 415
 416                 kfree_skb(skb);
 417                 return -ETIMEDOUT;
 418         }
 419
 420         /* XXX: idev->cnf.proxy_ndp? */
 421         if (net->ipv6.devconf_all->proxy_ndp &&
 422             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 423                 int proxied = ip6_forward_proxy_check(skb);
 424                 if (proxied > 0)
 425                         return ip6_input(skb);
 426                 else if (proxied < 0) {
 427                         IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 428                                          IPSTATS_MIB_INDISCARDS);
 429                         goto drop;
 430                 }
 431         }
 432
 433         if (!xfrm6_route_forward(skb)) {
 434                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 435                                  IPSTATS_MIB_INDISCARDS);
 436                 goto drop;
 437         }
 438         dst = skb_dst(skb);
 439
 440         /* IPv6 specs say nothing about it, but it is clear that we cannot
 441            send redirects to source routed frames.
 442            We don't send redirects to frames decapsulated from IPsec.
 443          */
 444         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 445                 struct in6_addr *target = NULL;
 446                 struct inet_peer *peer;
 447                 struct rt6_info *rt;
 448
 449                 /*
 450                  *      incoming and outgoing devices are the same
 451                  *      send a redirect.
 452                  */
 453
 454                 rt = (struct rt6_info *) dst;
 455                 if (rt->rt6i_flags & RTF_GATEWAY)
 456                         target = &rt->rt6i_gateway;
 457                 else
 458                         target = &hdr->daddr;
 459
 460                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 461
 462                 /* Limit redirects both by destination (here)
 463                    and by source (inside ndisc_send_redirect)
 464                  */
 465                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 466                         ndisc_send_redirect(skb, target);
 467                 if (peer)
 468                         inet_putpeer(peer);
 469         } else {
 470                 int addrtype = ipv6_addr_type(&hdr->saddr);
 471
 472                 /* This check is security critical. */
 473                 if (addrtype == IPV6_ADDR_ANY ||
 474                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 475                         goto error;
 476                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 477                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 478                                     ICMPV6_NOT_NEIGHBOUR, 0);
 479                         goto error;
 480                 }
 481         }
 482
 483         mtu = ip6_dst_mtu_forward(dst);
 484         if (mtu < IPV6_MIN_MTU)
 485                 mtu = IPV6_MIN_MTU;
 486
 487         if (ip6_pkt_too_big(skb, mtu)) {
 488                 /* Again, force OUTPUT device used as source address */
 489                 skb->dev = dst->dev;
 490                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 491                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 492                                  IPSTATS_MIB_INTOOBIGERRORS);
 493                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 494                                  IPSTATS_MIB_FRAGFAILS);
 495                 kfree_skb(skb);
 496                 return -EMSGSIZE;
 497         }
 498
 499         if (skb_cow(skb, dst->dev->hard_header_len)) {
 500                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 501                                  IPSTATS_MIB_OUTDISCARDS);
 502                 goto drop;
 503         }
 504
 505         hdr = ipv6_hdr(skb);
 506
 507         /* Mangling hops number delayed to point after skb COW */
 508
 509         hdr->hop_limit--;
 510
 511         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 512         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 513         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 514                        ip6_forward_finish);
 515
 516 error:
 517         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 518 drop:
 519         kfree_skb(skb);
 520         return -EINVAL;
 521 }
 522
 523 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 524 {
 525         to->pkt_type = from->pkt_type;
 526         to->priority = from->priority;
 527         to->protocol = from->protocol;
 528         skb_dst_drop(to);
 529         skb_dst_set(to, dst_clone(skb_dst(from)));
 530         to->dev = from->dev;
 531         to->mark = from->mark;
 532
 533 #ifdef CONFIG_NET_SCHED
 534         to->tc_index = from->tc_index;
 535 #endif
 536         nf_copy(to, from);
 537         skb_copy_secmark(to, from);
 538 }
 539
 540 static void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
 541 {
 542         static u32 ip6_idents_hashrnd __read_mostly;
 543         u32 hash, id;
 544
 545         net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));
 546
 547         hash = __ipv6_addr_jhash(&rt->rt6i_dst.addr, ip6_idents_hashrnd);
 548         hash = __ipv6_addr_jhash(&rt->rt6i_src.addr, hash);
 549
 550         id = ip_idents_reserve(hash, 1);
 551         fhdr->identification = htonl(id);
 552 }
 553
 554 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 555 {
 556         struct sk_buff *frag;
 557         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 558         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 559         struct ipv6hdr *tmp_hdr;
 560         struct frag_hdr *fh;
 561         unsigned int mtu, hlen, left, len;
 562         int hroom, troom;
 563         __be32 frag_id = 0;
 564         int ptr, offset = 0, err = 0;
 565         u8 *prevhdr, nexthdr = 0;
 566         struct net *net = dev_net(skb_dst(skb)->dev);
 567
 568         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 569         nexthdr = *prevhdr;
 570
 571         mtu = ip6_skb_dst_mtu(skb);
 572
 573         /* We must not fragment if the socket is set to force MTU discovery
 574          * or if the skb it not generated by a local socket.
 575          */
 576         if (unlikely(!skb->ignore_df && skb->len > mtu) ||
 577                      (IP6CB(skb)->frag_max_size &&
 578                       IP6CB(skb)->frag_max_size > mtu)) {
 579                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 580                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 581
 582                 skb->dev = skb_dst(skb)->dev;
 583                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 584                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 585                               IPSTATS_MIB_FRAGFAILS);
 586                 kfree_skb(skb);
 587                 return -EMSGSIZE;
 588         }
 589
 590         if (np && np->frag_size < mtu) {
 591                 if (np->frag_size)
 592                         mtu = np->frag_size;
 593         }
 594         mtu -= hlen + sizeof(struct frag_hdr);
 595
 596         if (skb_has_frag_list(skb)) {
 597                 int first_len = skb_pagelen(skb);
 598                 struct sk_buff *frag2;
 599
 600                 if (first_len - hlen > mtu ||
 601                     ((first_len - hlen) & 7) ||
 602                     skb_cloned(skb))
 603                         goto slow_path;
 604
 605                 skb_walk_frags(skb, frag) {
 606                         /* Correct geometry. */
 607                         if (frag->len > mtu ||
 608                             ((frag->len & 7) && frag->next) ||
 609                             skb_headroom(frag) < hlen)
 610                                 goto slow_path_clean;
 611
 612                         /* Partially cloned skb? */
 613                         if (skb_shared(frag))
 614                                 goto slow_path_clean;
 615
 616                         BUG_ON(frag->sk);
 617                         if (skb->sk) {
 618                                 frag->sk = skb->sk;
 619                                 frag->destructor = sock_wfree;
 620                         }
 621                         skb->truesize -= frag->truesize;
 622                 }
 623
 624                 err = 0;
 625                 offset = 0;
 626                 frag = skb_shinfo(skb)->frag_list;
 627                 skb_frag_list_init(skb);
 628                 /* BUILD HEADER */
 629
 630                 *prevhdr = NEXTHDR_FRAGMENT;
 631                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 632                 if (!tmp_hdr) {
 633                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 634                                       IPSTATS_MIB_FRAGFAILS);
 635                         return -ENOMEM;
 636                 }
 637
 638                 __skb_pull(skb, hlen);
 639                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 640                 __skb_push(skb, hlen);
 641                 skb_reset_network_header(skb);
 642                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 643
 644                 ipv6_select_ident(fh, rt);
 645                 fh->nexthdr = nexthdr;
 646                 fh->reserved = 0;
 647                 fh->frag_off = htons(IP6_MF);
 648                 frag_id = fh->identification;
 649
 650                 first_len = skb_pagelen(skb);
 651                 skb->data_len = first_len - skb_headlen(skb);
 652                 skb->len = first_len;
 653                 ipv6_hdr(skb)->payload_len = htons(first_len -
 654                                                    sizeof(struct ipv6hdr));
 655
 656                 dst_hold(&rt->dst);
 657
 658                 for (;;) {
 659                         /* Prepare header of the next frame,
 660                          * before previous one went down. */
 661                         if (frag) {
 662                                 frag->ip_summed = CHECKSUM_NONE;
 663                                 skb_reset_transport_header(frag);
 664                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 665                                 __skb_push(frag, hlen);
 666                                 skb_reset_network_header(frag);
 667                                 memcpy(skb_network_header(frag), tmp_hdr,
 668                                        hlen);
 669                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 670                                 fh->nexthdr = nexthdr;
 671                                 fh->reserved = 0;
 672                                 fh->frag_off = htons(offset);
 673                                 if (frag->next != NULL)
 674                                         fh->frag_off |= htons(IP6_MF);
 675                                 fh->identification = frag_id;
 676                                 ipv6_hdr(frag)->payload_len =
 677                                                 htons(frag->len -
 678                                                       sizeof(struct ipv6hdr));
 679                                 ip6_copy_metadata(frag, skb);
 680                         }
 681
 682                         err = output(skb);
 683                         if (!err)
 684                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 685                                               IPSTATS_MIB_FRAGCREATES);
 686
 687                         if (err || !frag)
 688                                 break;
 689
 690                         skb = frag;
 691                         frag = skb->next;
 692                         skb->next = NULL;
 693                 }
 694
 695                 kfree(tmp_hdr);
 696
 697                 if (err == 0) {
 698                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 699                                       IPSTATS_MIB_FRAGOKS);
 700                         ip6_rt_put(rt);
 701                         return 0;
 702                 }
 703
 704                 kfree_skb_list(frag);
 705
 706                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 707                               IPSTATS_MIB_FRAGFAILS);
 708                 ip6_rt_put(rt);
 709                 return err;
 710
 711 slow_path_clean:
 712                 skb_walk_frags(skb, frag2) {
 713                         if (frag2 == frag)
 714                                 break;
 715                         frag2->sk = NULL;
 716                         frag2->destructor = NULL;
 717                         skb->truesize += frag2->truesize;
 718                 }
 719         }
 720
 721 slow_path:
 722         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 723             skb_checksum_help(skb))
 724                 goto fail;
 725
 726         left = skb->len - hlen;         /* Space per frame */
 727         ptr = hlen;                     /* Where to start from */
 728
 729         /*
 730          *      Fragment the datagram.
 731          */
 732
 733         *prevhdr = NEXTHDR_FRAGMENT;
 734         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 735         troom = rt->dst.dev->needed_tailroom;
 736
 737         /*
 738          *      Keep copying data until we run out.
 739          */
 740         while (left > 0)        {
 741                 len = left;
 742                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 743                 if (len > mtu)
 744                         len = mtu;
 745                 /* IF: we are not sending up to and including the packet end
 746                    then align the next start on an eight byte boundary */
 747                 if (len < left) {
 748                         len &= ~7;
 749                 }
 750                 /*
 751                  *      Allocate buffer.
 752                  */
 753
 754                 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 755                                       hroom + troom, GFP_ATOMIC)) == NULL) {
 756                         NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 757                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 758                                       IPSTATS_MIB_FRAGFAILS);
 759                         err = -ENOMEM;
 760                         goto fail;
 761                 }
 762
 763                 /*
 764                  *      Set up data on packet
 765                  */
 766
 767                 ip6_copy_metadata(frag, skb);
 768                 skb_reserve(frag, hroom);
 769                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 770                 skb_reset_network_header(frag);
 771                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 772                 frag->transport_header = (frag->network_header + hlen +
 773                                           sizeof(struct frag_hdr));
 774
 775                 /*
 776                  *      Charge the memory for the fragment to any owner
 777                  *      it might possess
 778                  */
 779                 if (skb->sk)
 780                         skb_set_owner_w(frag, skb->sk);
 781
 782                 /*
 783                  *      Copy the packet header into the new buffer.
 784                  */
 785                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 786
 787                 /*
 788                  *      Build fragment header.
 789                  */
 790                 fh->nexthdr = nexthdr;
 791                 fh->reserved = 0;
 792                 if (!frag_id) {
 793                         ipv6_select_ident(fh, rt);
 794                         frag_id = fh->identification;
 795                 } else
 796                         fh->identification = frag_id;
 797
 798                 /*
 799                  *      Copy a block of the IP datagram.
 800                  */
 801                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 802                                      len));
 803                 left -= len;
 804
 805                 fh->frag_off = htons(offset);
 806                 if (left > 0)
 807                         fh->frag_off |= htons(IP6_MF);
 808                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 809                                                     sizeof(struct ipv6hdr));
 810
 811                 ptr += len;
 812                 offset += len;
 813
 814                 /*
 815                  *      Put this fragment into the sending queue.
 816                  */
 817                 err = output(frag);
 818                 if (err)
 819                         goto fail;
 820
 821                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 822                               IPSTATS_MIB_FRAGCREATES);
 823         }
 824         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 825                       IPSTATS_MIB_FRAGOKS);
 826         consume_skb(skb);
 827         return err;
 828
 829 fail:
 830         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 831                       IPSTATS_MIB_FRAGFAILS);
 832         kfree_skb(skb);
 833         return err;
 834 }
 835
 836 static inline int ip6_rt_check(const struct rt6key *rt_key,
 837                                const struct in6_addr *fl_addr,
 838                                const struct in6_addr *addr_cache)
 839 {
 840         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 841                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 842 }
 843
 844 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 845                                           struct dst_entry *dst,
 846                                           const struct flowi6 *fl6)
 847 {
 848         struct ipv6_pinfo *np = inet6_sk(sk);
 849         struct rt6_info *rt;
 850
 851         if (!dst)
 852                 goto out;
 853
 854         if (dst->ops->family != AF_INET6) {
 855                 dst_release(dst);
 856                 return NULL;
 857         }
 858
 859         rt = (struct rt6_info *)dst;
 860         /* Yes, checking route validity in not connected
 861          * case is not very simple. Take into account,
 862          * that we do not support routing by source, TOS,
 863          * and MSG_DONTROUTE            --ANK (980726)
 864          *
 865          * 1. ip6_rt_check(): If route was host route,
 866          *    check that cached destination is current.
 867          *    If it is network route, we still may
 868          *    check its validity using saved pointer
 869          *    to the last used address: daddr_cache.
 870          *    We do not want to save whole address now,
 871          *    (because main consumer of this service
 872          *    is tcp, which has not this problem),
 873          *    so that the last trick works only on connected
 874          *    sockets.
 875          * 2. oif also should be the same.
 876          */
 877         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 878 #ifdef CONFIG_IPV6_SUBTREES
 879             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 880 #endif
 881             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 882                 dst_release(dst);
 883                 dst = NULL;
 884         }
 885
 886 out:
 887         return dst;
 888 }
 889
 890 static int ip6_dst_lookup_tail(struct sock *sk,
 891                                struct dst_entry **dst, struct flowi6 *fl6)
 892 {
 893         struct net *net = sock_net(sk);
 894 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 895         struct neighbour *n;
 896         struct rt6_info *rt;
 897 #endif
 898         int err;
 899
 900         if (*dst == NULL)
 901                 *dst = ip6_route_output(net, sk, fl6);
 902
 903         if ((err = (*dst)->error))
 904                 goto out_err_release;
 905
 906         if (ipv6_addr_any(&fl6->saddr)) {
 907                 struct rt6_info *rt = (struct rt6_info *) *dst;
 908                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 909                                           sk ? inet6_sk(sk)->srcprefs : 0,
 910                                           &fl6->saddr);
 911                 if (err)
 912                         goto out_err_release;
 913         }
 914
 915 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 916         /*
 917          * Here if the dst entry we've looked up
 918          * has a neighbour entry that is in the INCOMPLETE
 919          * state and the src address from the flow is
 920          * marked as OPTIMISTIC, we release the found
 921          * dst entry and replace it instead with the
 922          * dst entry of the nexthop router
 923          */
 924         rt = (struct rt6_info *) *dst;
 925         rcu_read_lock_bh();
 926         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
 927         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 928         rcu_read_unlock_bh();
 929
 930         if (err) {
 931                 struct inet6_ifaddr *ifp;
 932                 struct flowi6 fl_gw6;
 933                 int redirect;
 934
 935                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 936                                       (*dst)->dev, 1);
 937
 938                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 939                 if (ifp)
 940                         in6_ifa_put(ifp);
 941
 942                 if (redirect) {
 943                         /*
 944                          * We need to get the dst entry for the
 945                          * default router instead
 946                          */
 947                         dst_release(*dst);
 948                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 949                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 950                         *dst = ip6_route_output(net, sk, &fl_gw6);
 951                         if ((err = (*dst)->error))
 952                                 goto out_err_release;
 953                 }
 954         }
 955 #endif
 956
 957         return 0;
 958
 959 out_err_release:
 960         if (err == -ENETUNREACH)
 961                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 962         dst_release(*dst);
 963         *dst = NULL;
 964         return err;
 965 }
 966
 967 /**
 968  *      ip6_dst_lookup - perform route lookup on flow
 969  *      @sk: socket which provides route info
 970  *      @dst: pointer to dst_entry * for result
 971  *      @fl6: flow to lookup
 972  *
 973  *      This function performs a route lookup on the given flow.
 974  *
 975  *      It returns zero on success, or a standard errno code on error.
 976  */
 977 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 978 {
 979         *dst = NULL;
 980         return ip6_dst_lookup_tail(sk, dst, fl6);
 981 }
 982 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 983
 984 /**
 985  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 986  *      @sk: socket which provides route info
 987  *      @fl6: flow to lookup
 988  *      @final_dst: final destination address for ipsec lookup
 989  *
 990  *      This function performs a route lookup on the given flow.
 991  *
 992  *      It returns a valid dst pointer on success, or a pointer encoded
 993  *      error code.
 994  */
 995 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 996                                       const struct in6_addr *final_dst)
 997 {
 998         struct dst_entry *dst = NULL;
 999         int err;
1000
1001         err = ip6_dst_lookup_tail(sk, &dst, fl6);
1002         if (err)
1003                 return ERR_PTR(err);
1004         if (final_dst)
1005                 fl6->daddr = *final_dst;
1006
1007         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1008 }
1009 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1010
1011 /**
1012  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1013  *      @sk: socket which provides the dst cache and route info
1014  *      @fl6: flow to lookup
1015  *      @final_dst: final destination address for ipsec lookup
1016  *
1017  *      This function performs a route lookup on the given flow with the
1018  *      possibility of using the cached route in the socket if it is valid.
1019  *      It will take the socket dst lock when operating on the dst cache.
1020  *      As a result, this function can only be used in process context.
1021  *
1022  *      It returns a valid dst pointer on success, or a pointer encoded
1023  *      error code.
1024  */
1025 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1026                                          const struct in6_addr *final_dst)
1027 {
1028         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1029         int err;
1030
1031         dst = ip6_sk_dst_check(sk, dst, fl6);
1032
1033         err = ip6_dst_lookup_tail(sk, &dst, fl6);
1034         if (err)
1035                 return ERR_PTR(err);
1036         if (final_dst)
1037                 fl6->daddr = *final_dst;
1038
1039         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1040 }
1041 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1042
1043 static inline int ip6_ufo_append_data(struct sock *sk,
1044                         int getfrag(void *from, char *to, int offset, int len,
1045                         int odd, struct sk_buff *skb),
1046                         void *from, int length, int hh_len, int fragheaderlen,
1047                         int transhdrlen, int mtu, unsigned int flags,
1048                         struct rt6_info *rt)
1049
1050 {
1051         struct sk_buff *skb;
1052         struct frag_hdr fhdr;
1053         int err;
1054
1055         /* There is support for UDP large send offload by network
1056          * device, so create one single skb packet containing complete
1057          * udp datagram
1058          */
1059         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1060                 skb = sock_alloc_send_skb(sk,
1061                         hh_len + fragheaderlen + transhdrlen + 20,
1062                         (flags & MSG_DONTWAIT), &err);
1063                 if (skb == NULL)
1064                         return err;
1065
1066                 /* reserve space for Hardware header */
1067                 skb_reserve(skb, hh_len);
1068
1069                 /* create space for UDP/IP header */
1070                 skb_put(skb, fragheaderlen + transhdrlen);
1071
1072                 /* initialize network header pointer */
1073                 skb_reset_network_header(skb);
1074
1075                 /* initialize protocol header pointer */
1076                 skb->transport_header = skb->network_header + fragheaderlen;
1077
1078                 skb->protocol = htons(ETH_P_IPV6);
1079                 skb->csum = 0;
1080
1081                 __skb_queue_tail(&sk->sk_write_queue, skb);
1082         } else if (skb_is_gso(skb)) {
1083                 goto append;
1084         }
1085
1086         skb->ip_summed = CHECKSUM_PARTIAL;
1087         /* Specify the length of each IPv6 datagram fragment.
1088          * It has to be a multiple of 8.
1089          */
1090         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1091                                      sizeof(struct frag_hdr)) & ~7;
1092         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1093         ipv6_select_ident(&fhdr, rt);
1094         skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1095
1096 append:
1097         return skb_append_datato_frags(sk, skb, getfrag, from,
1098                                        (length - transhdrlen));
1099 }
1100
1101 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1102                                                gfp_t gfp)
1103 {
1104         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1105 }
1106
1107 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1108                                                 gfp_t gfp)
1109 {
1110         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1111 }
1112
1113 static void ip6_append_data_mtu(unsigned int *mtu,
1114                                 int *maxfraglen,
1115                                 unsigned int fragheaderlen,
1116                                 struct sk_buff *skb,
1117                                 struct rt6_info *rt,
1118                                 unsigned int orig_mtu)
1119 {
1120         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1121                 if (skb == NULL) {
1122                         /* first fragment, reserve header_len */
1123                         *mtu = orig_mtu - rt->dst.header_len;
1124
1125                 } else {
1126                         /*
1127                          * this fragment is not first, the headers
1128                          * space is regarded as data space.
1129                          */
1130                         *mtu = orig_mtu;
1131                 }
1132                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1133                               + fragheaderlen - sizeof(struct frag_hdr);
1134         }
1135 }
1136
1137 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1138         int offset, int len, int odd, struct sk_buff *skb),
1139         void *from, int length, int transhdrlen,
1140         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1141         struct rt6_info *rt, unsigned int flags, int dontfrag)
1142 {
1143         struct inet_sock *inet = inet_sk(sk);
1144         struct ipv6_pinfo *np = inet6_sk(sk);
1145         struct inet_cork *cork;
1146         struct sk_buff *skb, *skb_prev = NULL;
1147         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1148         int exthdrlen;
1149         int dst_exthdrlen;
1150         int hh_len;
1151         int copy;
1152         int err;
1153         int offset = 0;
1154         __u8 tx_flags = 0;
1155         u32 tskey = 0;
1156
1157         if (flags&MSG_PROBE)
1158                 return 0;
1159         cork = &inet->cork.base;
1160         if (skb_queue_empty(&sk->sk_write_queue)) {
1161                 /*
1162                  * setup for corking
1163                  */
1164                 if (opt) {
1165                         if (WARN_ON(np->cork.opt))
1166                                 return -EINVAL;
1167
1168                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1169                         if (unlikely(np->cork.opt == NULL))
1170                                 return -ENOBUFS;
1171
1172                         np->cork.opt->tot_len = opt->tot_len;
1173                         np->cork.opt->opt_flen = opt->opt_flen;
1174                         np->cork.opt->opt_nflen = opt->opt_nflen;
1175
1176                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1177                                                             sk->sk_allocation);
1178                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1179                                 return -ENOBUFS;
1180
1181                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1182                                                             sk->sk_allocation);
1183                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1184                                 return -ENOBUFS;
1185
1186                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1187                                                            sk->sk_allocation);
1188                         if (opt->hopopt && !np->cork.opt->hopopt)
1189                                 return -ENOBUFS;
1190
1191                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1192                                                             sk->sk_allocation);
1193                         if (opt->srcrt && !np->cork.opt->srcrt)
1194                                 return -ENOBUFS;
1195
1196                         /* need source address above miyazawa*/
1197                 }
1198                 dst_hold(&rt->dst);
1199                 cork->dst = &rt->dst;
1200                 inet->cork.fl.u.ip6 = *fl6;
1201                 np->cork.hop_limit = hlimit;
1202                 np->cork.tclass = tclass;
1203                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1204                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1205                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1206                 else
1207                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1208                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1209                 if (np->frag_size < mtu) {
1210                         if (np->frag_size)
1211                                 mtu = np->frag_size;
1212                 }
1213                 cork->fragsize = mtu;
1214                 if (dst_allfrag(rt->dst.path))
1215                         cork->flags |= IPCORK_ALLFRAG;
1216                 cork->length = 0;
1217                 exthdrlen = (opt ? opt->opt_flen : 0);
1218                 length += exthdrlen;
1219                 transhdrlen += exthdrlen;
1220                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1221         } else {
1222                 rt = (struct rt6_info *)cork->dst;
1223                 fl6 = &inet->cork.fl.u.ip6;
1224                 opt = np->cork.opt;
1225                 transhdrlen = 0;
1226                 exthdrlen = 0;
1227                 dst_exthdrlen = 0;
1228                 mtu = cork->fragsize;
1229         }
1230         orig_mtu = mtu;
1231
1232         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1233
1234         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1235                         (opt ? opt->opt_nflen : 0);
1236         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1237                      sizeof(struct frag_hdr);
1238
1239         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1240                 unsigned int maxnonfragsize, headersize;
1241
1242                 headersize = sizeof(struct ipv6hdr) +
1243                              (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1244                              (dst_allfrag(&rt->dst) ?
1245                               sizeof(struct frag_hdr) : 0) +
1246                              rt->rt6i_nfheader_len;
1247
1248                 if (ip6_sk_ignore_df(sk))
1249                         maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1250                 else
1251                         maxnonfragsize = mtu;
1252
1253                 /* dontfrag active */
1254                 if ((cork->length + length > mtu - headersize) && dontfrag &&
1255                     (sk->sk_protocol == IPPROTO_UDP ||
1256                      sk->sk_protocol == IPPROTO_RAW)) {
1257                         ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1258                                                    sizeof(struct ipv6hdr));
1259                         goto emsgsize;
1260                 }
1261
1262                 if (cork->length + length > maxnonfragsize - headersize) {
1263 emsgsize:
1264                         ipv6_local_error(sk, EMSGSIZE, fl6,
1265                                          mtu - headersize +
1266                                          sizeof(struct ipv6hdr));
1267                         return -EMSGSIZE;
1268                 }
1269         }
1270
1271         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1272                 sock_tx_timestamp(sk, &tx_flags);
1273                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1274                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1275                         tskey = sk->sk_tskey++;
1276         }
1277
1278         /*
1279          * Let's try using as much space as possible.
1280          * Use MTU if total length of the message fits into the MTU.
1281          * Otherwise, we need to reserve fragment header and
1282          * fragment alignment (= 8-15 octects, in total).
1283          *
1284          * Note that we may need to "move" the data from the tail of
1285          * of the buffer to the new fragment when we split
1286          * the message.
1287          *
1288          * FIXME: It may be fragmented into multiple chunks
1289          *        at once if non-fragmentable extension headers
1290          *        are too large.
1291          * --yoshfuji
1292          */
1293
1294         skb = skb_peek_tail(&sk->sk_write_queue);
1295         cork->length += length;
1296         if (((length > mtu) ||
1297              (skb && skb_is_gso(skb))) &&
1298             (sk->sk_protocol == IPPROTO_UDP) &&
1299             (rt->dst.dev->features & NETIF_F_UFO)) {
1300                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1301                                           hh_len, fragheaderlen,
1302                                           transhdrlen, mtu, flags, rt);
1303                 if (err)
1304                         goto error;
1305                 return 0;
1306         }
1307
1308         if (!skb)
1309                 goto alloc_new_skb;
1310
1311         while (length > 0) {
1312                 /* Check if the remaining data fits into current packet. */
1313                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1314                 if (copy < length)
1315                         copy = maxfraglen - skb->len;
1316
1317                 if (copy <= 0) {
1318                         char *data;
1319                         unsigned int datalen;
1320                         unsigned int fraglen;
1321                         unsigned int fraggap;
1322                         unsigned int alloclen;
1323 alloc_new_skb:
1324                         /* There's no room in the current skb */
1325                         if (skb)
1326                                 fraggap = skb->len - maxfraglen;
1327                         else
1328                                 fraggap = 0;
1329                         /* update mtu and maxfraglen if necessary */
1330                         if (skb == NULL || skb_prev == NULL)
1331                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1332                                                     fragheaderlen, skb, rt,
1333                                                     orig_mtu);
1334
1335                         skb_prev = skb;
1336
1337                         /*
1338                          * If remaining data exceeds the mtu,
1339                          * we know we need more fragment(s).
1340                          */
1341                         datalen = length + fraggap;
1342
1343                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1344                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1345                         if ((flags & MSG_MORE) &&
1346                             !(rt->dst.dev->features&NETIF_F_SG))
1347                                 alloclen = mtu;
1348                         else
1349                                 alloclen = datalen + fragheaderlen;
1350
1351                         alloclen += dst_exthdrlen;
1352
1353                         if (datalen != length + fraggap) {
1354                                 /*
1355                                  * this is not the last fragment, the trailer
1356                                  * space is regarded as data space.
1357                                  */
1358                                 datalen += rt->dst.trailer_len;
1359                         }
1360
1361                         alloclen += rt->dst.trailer_len;
1362                         fraglen = datalen + fragheaderlen;
1363
1364                         /*
1365                          * We just reserve space for fragment header.
1366                          * Note: this may be overallocation if the message
1367                          * (without MSG_MORE) fits into the MTU.
1368                          */
1369                         alloclen += sizeof(struct frag_hdr);
1370
1371                         if (transhdrlen) {
1372                                 skb = sock_alloc_send_skb(sk,
1373                                                 alloclen + hh_len,
1374                                                 (flags & MSG_DONTWAIT), &err);
1375                         } else {
1376                                 skb = NULL;
1377                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1378                                     2 * sk->sk_sndbuf)
1379                                         skb = sock_wmalloc(sk,
1380                                                            alloclen + hh_len, 1,
1381                                                            sk->sk_allocation);
1382                                 if (unlikely(skb == NULL))
1383                                         err = -ENOBUFS;
1384                         }
1385                         if (skb == NULL)
1386                                 goto error;
1387                         /*
1388                          *      Fill in the control structures
1389                          */
1390                         skb->protocol = htons(ETH_P_IPV6);
1391                         skb->ip_summed = CHECKSUM_NONE;
1392                         skb->csum = 0;
1393                         /* reserve for fragmentation and ipsec header */
1394                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1395                                     dst_exthdrlen);
1396
1397                         /* Only the initial fragment is time stamped */
1398                         skb_shinfo(skb)->tx_flags = tx_flags;
1399                         tx_flags = 0;
1400                         skb_shinfo(skb)->tskey = tskey;
1401                         tskey = 0;
1402
1403                         /*
1404                          *      Find where to start putting bytes
1405                          */
1406                         data = skb_put(skb, fraglen);
1407                         skb_set_network_header(skb, exthdrlen);
1408                         data += fragheaderlen;
1409                         skb->transport_header = (skb->network_header +
1410                                                  fragheaderlen);
1411                         if (fraggap) {
1412                                 skb->csum = skb_copy_and_csum_bits(
1413                                         skb_prev, maxfraglen,
1414                                         data + transhdrlen, fraggap, 0);
1415                                 skb_prev->csum = csum_sub(skb_prev->csum,
1416                                                           skb->csum);
1417                                 data += fraggap;
1418                                 pskb_trim_unique(skb_prev, maxfraglen);
1419                         }
1420                         copy = datalen - transhdrlen - fraggap;
1421
1422                         if (copy < 0) {
1423                                 err = -EINVAL;
1424                                 kfree_skb(skb);
1425                                 goto error;
1426                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1427                                 err = -EFAULT;
1428                                 kfree_skb(skb);
1429                                 goto error;
1430                         }
1431
1432                         offset += copy;
1433                         length -= datalen - fraggap;
1434                         transhdrlen = 0;
1435                         exthdrlen = 0;
1436                         dst_exthdrlen = 0;
1437
1438                         /*
1439                          * Put the packet on the pending queue
1440                          */
1441                         __skb_queue_tail(&sk->sk_write_queue, skb);
1442                         continue;
1443                 }
1444
1445                 if (copy > length)
1446                         copy = length;
1447
1448                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1449                         unsigned int off;
1450
1451                         off = skb->len;
1452                         if (getfrag(from, skb_put(skb, copy),
1453                                                 offset, copy, off, skb) < 0) {
1454                                 __skb_trim(skb, off);
1455                                 err = -EFAULT;
1456                                 goto error;
1457                         }
1458                 } else {
1459                         int i = skb_shinfo(skb)->nr_frags;
1460                         struct page_frag *pfrag = sk_page_frag(sk);
1461
1462                         err = -ENOMEM;
1463                         if (!sk_page_frag_refill(sk, pfrag))
1464                                 goto error;
1465
1466                         if (!skb_can_coalesce(skb, i, pfrag->page,
1467                                               pfrag->offset)) {
1468                                 err = -EMSGSIZE;
1469                                 if (i == MAX_SKB_FRAGS)
1470                                         goto error;
1471
1472                                 __skb_fill_page_desc(skb, i, pfrag->page,
1473                                                      pfrag->offset, 0);
1474                                 skb_shinfo(skb)->nr_frags = ++i;
1475                                 get_page(pfrag->page);
1476                         }
1477                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1478                         if (getfrag(from,
1479                                     page_address(pfrag->page) + pfrag->offset,
1480                                     offset, copy, skb->len, skb) < 0)
1481                                 goto error_efault;
1482
1483                         pfrag->offset += copy;
1484                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1485                         skb->len += copy;
1486                         skb->data_len += copy;
1487                         skb->truesize += copy;
1488                         atomic_add(copy, &sk->sk_wmem_alloc);
1489                 }
1490                 offset += copy;
1491                 length -= copy;
1492         }
1493
1494         return 0;
1495
1496 error_efault:
1497         err = -EFAULT;
1498 error:
1499         cork->length -= length;
1500         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1501         return err;
1502 }
1503 EXPORT_SYMBOL_GPL(ip6_append_data);
1504
1505 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1506 {
1507         if (np->cork.opt) {
1508                 kfree(np->cork.opt->dst0opt);
1509                 kfree(np->cork.opt->dst1opt);
1510                 kfree(np->cork.opt->hopopt);
1511                 kfree(np->cork.opt->srcrt);
1512                 kfree(np->cork.opt);
1513                 np->cork.opt = NULL;
1514         }
1515
1516         if (inet->cork.base.dst) {
1517                 dst_release(inet->cork.base.dst);
1518                 inet->cork.base.dst = NULL;
1519                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1520         }
1521         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1522 }
1523
1524 int ip6_push_pending_frames(struct sock *sk)
1525 {
1526         struct sk_buff *skb, *tmp_skb;
1527         struct sk_buff **tail_skb;
1528         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1529         struct inet_sock *inet = inet_sk(sk);
1530         struct ipv6_pinfo *np = inet6_sk(sk);
1531         struct net *net = sock_net(sk);
1532         struct ipv6hdr *hdr;
1533         struct ipv6_txoptions *opt = np->cork.opt;
1534         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1535         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1536         unsigned char proto = fl6->flowi6_proto;
1537         int err = 0;
1538
1539         if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1540                 goto out;
1541         tail_skb = &(skb_shinfo(skb)->frag_list);
1542
1543         /* move skb->data to ip header from ext header */
1544         if (skb->data < skb_network_header(skb))
1545                 __skb_pull(skb, skb_network_offset(skb));
1546         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1547                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1548                 *tail_skb = tmp_skb;
1549                 tail_skb = &(tmp_skb->next);
1550                 skb->len += tmp_skb->len;
1551                 skb->data_len += tmp_skb->len;
1552                 skb->truesize += tmp_skb->truesize;
1553                 tmp_skb->destructor = NULL;
1554                 tmp_skb->sk = NULL;
1555         }
1556
1557         /* Allow local fragmentation. */
1558         skb->ignore_df = ip6_sk_ignore_df(sk);
1559
1560         *final_dst = fl6->daddr;
1561         __skb_pull(skb, skb_network_header_len(skb));
1562         if (opt && opt->opt_flen)
1563                 ipv6_push_frag_opts(skb, opt, &proto);
1564         if (opt && opt->opt_nflen)
1565                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1566
1567         skb_push(skb, sizeof(struct ipv6hdr));
1568         skb_reset_network_header(skb);
1569         hdr = ipv6_hdr(skb);
1570
1571         ip6_flow_hdr(hdr, np->cork.tclass,
1572                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1573                                         np->autoflowlabel));
1574         hdr->hop_limit = np->cork.hop_limit;
1575         hdr->nexthdr = proto;
1576         hdr->saddr = fl6->saddr;
1577         hdr->daddr = *final_dst;
1578
1579         skb->priority = sk->sk_priority;
1580         skb->mark = sk->sk_mark;
1581
1582         skb_dst_set(skb, dst_clone(&rt->dst));
1583         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1584         if (proto == IPPROTO_ICMPV6) {
1585                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1586
1587                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1588                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1589         }
1590
1591         err = ip6_local_out(skb);
1592         if (err) {
1593                 if (err > 0)
1594                         err = net_xmit_errno(err);
1595                 if (err)
1596                         goto error;
1597         }
1598
1599 out:
1600         ip6_cork_release(inet, np);
1601         return err;
1602 error:
1603         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1604         goto out;
1605 }
1606 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1607
1608 void ip6_flush_pending_frames(struct sock *sk)
1609 {
1610         struct sk_buff *skb;
1611
1612         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1613                 if (skb_dst(skb))
1614                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1615                                       IPSTATS_MIB_OUTDISCARDS);
1616                 kfree_skb(skb);
1617         }
1618
1619         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1620 }
1621 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);