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