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 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 541 {
 542         struct sk_buff *frag;
 543         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 544         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 545         struct ipv6hdr *tmp_hdr;
 546         struct frag_hdr *fh;
 547         unsigned int mtu, hlen, left, len;
 548         int hroom, troom;
 549         __be32 frag_id = 0;
 550         int ptr, offset = 0, err = 0;
 551         u8 *prevhdr, nexthdr = 0;
 552         struct net *net = dev_net(skb_dst(skb)->dev);
 553
 554         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 555         nexthdr = *prevhdr;
 556
 557         mtu = ip6_skb_dst_mtu(skb);
 558
 559         /* We must not fragment if the socket is set to force MTU discovery
 560          * or if the skb it not generated by a local socket.
 561          */
 562         if (unlikely(!skb->ignore_df && skb->len > mtu) ||
 563                      (IP6CB(skb)->frag_max_size &&
 564                       IP6CB(skb)->frag_max_size > mtu)) {
 565                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 566                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 567
 568                 skb->dev = skb_dst(skb)->dev;
 569                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 570                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 571                               IPSTATS_MIB_FRAGFAILS);
 572                 kfree_skb(skb);
 573                 return -EMSGSIZE;
 574         }
 575
 576         if (np && np->frag_size < mtu) {
 577                 if (np->frag_size)
 578                         mtu = np->frag_size;
 579         }
 580         mtu -= hlen + sizeof(struct frag_hdr);
 581
 582         if (skb_has_frag_list(skb)) {
 583                 int first_len = skb_pagelen(skb);
 584                 struct sk_buff *frag2;
 585
 586                 if (first_len - hlen > mtu ||
 587                     ((first_len - hlen) & 7) ||
 588                     skb_cloned(skb))
 589                         goto slow_path;
 590
 591                 skb_walk_frags(skb, frag) {
 592                         /* Correct geometry. */
 593                         if (frag->len > mtu ||
 594                             ((frag->len & 7) && frag->next) ||
 595                             skb_headroom(frag) < hlen)
 596                                 goto slow_path_clean;
 597
 598                         /* Partially cloned skb? */
 599                         if (skb_shared(frag))
 600                                 goto slow_path_clean;
 601
 602                         BUG_ON(frag->sk);
 603                         if (skb->sk) {
 604                                 frag->sk = skb->sk;
 605                                 frag->destructor = sock_wfree;
 606                         }
 607                         skb->truesize -= frag->truesize;
 608                 }
 609
 610                 err = 0;
 611                 offset = 0;
 612                 frag = skb_shinfo(skb)->frag_list;
 613                 skb_frag_list_init(skb);
 614                 /* BUILD HEADER */
 615
 616                 *prevhdr = NEXTHDR_FRAGMENT;
 617                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 618                 if (!tmp_hdr) {
 619                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 620                                       IPSTATS_MIB_FRAGFAILS);
 621                         return -ENOMEM;
 622                 }
 623
 624                 __skb_pull(skb, hlen);
 625                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 626                 __skb_push(skb, hlen);
 627                 skb_reset_network_header(skb);
 628                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 629
 630                 ipv6_select_ident(fh, rt);
 631                 fh->nexthdr = nexthdr;
 632                 fh->reserved = 0;
 633                 fh->frag_off = htons(IP6_MF);
 634                 frag_id = fh->identification;
 635
 636                 first_len = skb_pagelen(skb);
 637                 skb->data_len = first_len - skb_headlen(skb);
 638                 skb->len = first_len;
 639                 ipv6_hdr(skb)->payload_len = htons(first_len -
 640                                                    sizeof(struct ipv6hdr));
 641
 642                 dst_hold(&rt->dst);
 643
 644                 for (;;) {
 645                         /* Prepare header of the next frame,
 646                          * before previous one went down. */
 647                         if (frag) {
 648                                 frag->ip_summed = CHECKSUM_NONE;
 649                                 skb_reset_transport_header(frag);
 650                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 651                                 __skb_push(frag, hlen);
 652                                 skb_reset_network_header(frag);
 653                                 memcpy(skb_network_header(frag), tmp_hdr,
 654                                        hlen);
 655                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 656                                 fh->nexthdr = nexthdr;
 657                                 fh->reserved = 0;
 658                                 fh->frag_off = htons(offset);
 659                                 if (frag->next != NULL)
 660                                         fh->frag_off |= htons(IP6_MF);
 661                                 fh->identification = frag_id;
 662                                 ipv6_hdr(frag)->payload_len =
 663                                                 htons(frag->len -
 664                                                       sizeof(struct ipv6hdr));
 665                                 ip6_copy_metadata(frag, skb);
 666                         }
 667
 668                         err = output(skb);
 669                         if (!err)
 670                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 671                                               IPSTATS_MIB_FRAGCREATES);
 672
 673                         if (err || !frag)
 674                                 break;
 675
 676                         skb = frag;
 677                         frag = skb->next;
 678                         skb->next = NULL;
 679                 }
 680
 681                 kfree(tmp_hdr);
 682
 683                 if (err == 0) {
 684                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 685                                       IPSTATS_MIB_FRAGOKS);
 686                         ip6_rt_put(rt);
 687                         return 0;
 688                 }
 689
 690                 kfree_skb_list(frag);
 691
 692                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 693                               IPSTATS_MIB_FRAGFAILS);
 694                 ip6_rt_put(rt);
 695                 return err;
 696
 697 slow_path_clean:
 698                 skb_walk_frags(skb, frag2) {
 699                         if (frag2 == frag)
 700                                 break;
 701                         frag2->sk = NULL;
 702                         frag2->destructor = NULL;
 703                         skb->truesize += frag2->truesize;
 704                 }
 705         }
 706
 707 slow_path:
 708         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 709             skb_checksum_help(skb))
 710                 goto fail;
 711
 712         left = skb->len - hlen;         /* Space per frame */
 713         ptr = hlen;                     /* Where to start from */
 714
 715         /*
 716          *      Fragment the datagram.
 717          */
 718
 719         *prevhdr = NEXTHDR_FRAGMENT;
 720         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 721         troom = rt->dst.dev->needed_tailroom;
 722
 723         /*
 724          *      Keep copying data until we run out.
 725          */
 726         while (left > 0)        {
 727                 len = left;
 728                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 729                 if (len > mtu)
 730                         len = mtu;
 731                 /* IF: we are not sending up to and including the packet end
 732                    then align the next start on an eight byte boundary */
 733                 if (len < left) {
 734                         len &= ~7;
 735                 }
 736
 737                 /* Allocate buffer */
 738                 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 739                                  hroom + troom, GFP_ATOMIC);
 740                 if (!frag) {
 741                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 742                                       IPSTATS_MIB_FRAGFAILS);
 743                         err = -ENOMEM;
 744                         goto fail;
 745                 }
 746
 747                 /*
 748                  *      Set up data on packet
 749                  */
 750
 751                 ip6_copy_metadata(frag, skb);
 752                 skb_reserve(frag, hroom);
 753                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 754                 skb_reset_network_header(frag);
 755                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 756                 frag->transport_header = (frag->network_header + hlen +
 757                                           sizeof(struct frag_hdr));
 758
 759                 /*
 760                  *      Charge the memory for the fragment to any owner
 761                  *      it might possess
 762                  */
 763                 if (skb->sk)
 764                         skb_set_owner_w(frag, skb->sk);
 765
 766                 /*
 767                  *      Copy the packet header into the new buffer.
 768                  */
 769                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 770
 771                 /*
 772                  *      Build fragment header.
 773                  */
 774                 fh->nexthdr = nexthdr;
 775                 fh->reserved = 0;
 776                 if (!frag_id) {
 777                         ipv6_select_ident(fh, rt);
 778                         frag_id = fh->identification;
 779                 } else
 780                         fh->identification = frag_id;
 781
 782                 /*
 783                  *      Copy a block of the IP datagram.
 784                  */
 785                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 786                                      len));
 787                 left -= len;
 788
 789                 fh->frag_off = htons(offset);
 790                 if (left > 0)
 791                         fh->frag_off |= htons(IP6_MF);
 792                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 793                                                     sizeof(struct ipv6hdr));
 794
 795                 ptr += len;
 796                 offset += len;
 797
 798                 /*
 799                  *      Put this fragment into the sending queue.
 800                  */
 801                 err = output(frag);
 802                 if (err)
 803                         goto fail;
 804
 805                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 806                               IPSTATS_MIB_FRAGCREATES);
 807         }
 808         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 809                       IPSTATS_MIB_FRAGOKS);
 810         consume_skb(skb);
 811         return err;
 812
 813 fail:
 814         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 815                       IPSTATS_MIB_FRAGFAILS);
 816         kfree_skb(skb);
 817         return err;
 818 }
 819
 820 static inline int ip6_rt_check(const struct rt6key *rt_key,
 821                                const struct in6_addr *fl_addr,
 822                                const struct in6_addr *addr_cache)
 823 {
 824         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 825                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 826 }
 827
 828 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 829                                           struct dst_entry *dst,
 830                                           const struct flowi6 *fl6)
 831 {
 832         struct ipv6_pinfo *np = inet6_sk(sk);
 833         struct rt6_info *rt;
 834
 835         if (!dst)
 836                 goto out;
 837
 838         if (dst->ops->family != AF_INET6) {
 839                 dst_release(dst);
 840                 return NULL;
 841         }
 842
 843         rt = (struct rt6_info *)dst;
 844         /* Yes, checking route validity in not connected
 845          * case is not very simple. Take into account,
 846          * that we do not support routing by source, TOS,
 847          * and MSG_DONTROUTE            --ANK (980726)
 848          *
 849          * 1. ip6_rt_check(): If route was host route,
 850          *    check that cached destination is current.
 851          *    If it is network route, we still may
 852          *    check its validity using saved pointer
 853          *    to the last used address: daddr_cache.
 854          *    We do not want to save whole address now,
 855          *    (because main consumer of this service
 856          *    is tcp, which has not this problem),
 857          *    so that the last trick works only on connected
 858          *    sockets.
 859          * 2. oif also should be the same.
 860          */
 861         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 862 #ifdef CONFIG_IPV6_SUBTREES
 863             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 864 #endif
 865             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 866                 dst_release(dst);
 867                 dst = NULL;
 868         }
 869
 870 out:
 871         return dst;
 872 }
 873
 874 static int ip6_dst_lookup_tail(struct sock *sk,
 875                                struct dst_entry **dst, struct flowi6 *fl6)
 876 {
 877         struct net *net = sock_net(sk);
 878 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 879         struct neighbour *n;
 880         struct rt6_info *rt;
 881 #endif
 882         int err;
 883
 884         if (*dst == NULL)
 885                 *dst = ip6_route_output(net, sk, fl6);
 886
 887         err = (*dst)->error;
 888         if (err)
 889                 goto out_err_release;
 890
 891         if (ipv6_addr_any(&fl6->saddr)) {
 892                 struct rt6_info *rt = (struct rt6_info *) *dst;
 893                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 894                                           sk ? inet6_sk(sk)->srcprefs : 0,
 895                                           &fl6->saddr);
 896                 if (err)
 897                         goto out_err_release;
 898         }
 899
 900 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 901         /*
 902          * Here if the dst entry we've looked up
 903          * has a neighbour entry that is in the INCOMPLETE
 904          * state and the src address from the flow is
 905          * marked as OPTIMISTIC, we release the found
 906          * dst entry and replace it instead with the
 907          * dst entry of the nexthop router
 908          */
 909         rt = (struct rt6_info *) *dst;
 910         rcu_read_lock_bh();
 911         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
 912         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 913         rcu_read_unlock_bh();
 914
 915         if (err) {
 916                 struct inet6_ifaddr *ifp;
 917                 struct flowi6 fl_gw6;
 918                 int redirect;
 919
 920                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 921                                       (*dst)->dev, 1);
 922
 923                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 924                 if (ifp)
 925                         in6_ifa_put(ifp);
 926
 927                 if (redirect) {
 928                         /*
 929                          * We need to get the dst entry for the
 930                          * default router instead
 931                          */
 932                         dst_release(*dst);
 933                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 934                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 935                         *dst = ip6_route_output(net, sk, &fl_gw6);
 936                         err = (*dst)->error;
 937                         if (err)
 938                                 goto out_err_release;
 939                 }
 940         }
 941 #endif
 942
 943         return 0;
 944
 945 out_err_release:
 946         if (err == -ENETUNREACH)
 947                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 948         dst_release(*dst);
 949         *dst = NULL;
 950         return err;
 951 }
 952
 953 /**
 954  *      ip6_dst_lookup - perform route lookup on flow
 955  *      @sk: socket which provides route info
 956  *      @dst: pointer to dst_entry * for result
 957  *      @fl6: flow to lookup
 958  *
 959  *      This function performs a route lookup on the given flow.
 960  *
 961  *      It returns zero on success, or a standard errno code on error.
 962  */
 963 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 964 {
 965         *dst = NULL;
 966         return ip6_dst_lookup_tail(sk, dst, fl6);
 967 }
 968 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 969
 970 /**
 971  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 972  *      @sk: socket which provides route info
 973  *      @fl6: flow to lookup
 974  *      @final_dst: final destination address for ipsec lookup
 975  *
 976  *      This function performs a route lookup on the given flow.
 977  *
 978  *      It returns a valid dst pointer on success, or a pointer encoded
 979  *      error code.
 980  */
 981 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 982                                       const struct in6_addr *final_dst)
 983 {
 984         struct dst_entry *dst = NULL;
 985         int err;
 986
 987         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 988         if (err)
 989                 return ERR_PTR(err);
 990         if (final_dst)
 991                 fl6->daddr = *final_dst;
 992
 993         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
 994 }
 995 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 996
 997 /**
 998  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
 999  *      @sk: socket which provides the dst cache and route info
1000  *      @fl6: flow to lookup
1001  *      @final_dst: final destination address for ipsec lookup
1002  *
1003  *      This function performs a route lookup on the given flow with the
1004  *      possibility of using the cached route in the socket if it is valid.
1005  *      It will take the socket dst lock when operating on the dst cache.
1006  *      As a result, this function can only be used in process context.
1007  *
1008  *      It returns a valid dst pointer on success, or a pointer encoded
1009  *      error code.
1010  */
1011 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1012                                          const struct in6_addr *final_dst)
1013 {
1014         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1015         int err;
1016
1017         dst = ip6_sk_dst_check(sk, dst, fl6);
1018
1019         err = ip6_dst_lookup_tail(sk, &dst, fl6);
1020         if (err)
1021                 return ERR_PTR(err);
1022         if (final_dst)
1023                 fl6->daddr = *final_dst;
1024
1025         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1026 }
1027 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1028
1029 static inline int ip6_ufo_append_data(struct sock *sk,
1030                         int getfrag(void *from, char *to, int offset, int len,
1031                         int odd, struct sk_buff *skb),
1032                         void *from, int length, int hh_len, int fragheaderlen,
1033                         int transhdrlen, int mtu, unsigned int flags,
1034                         struct rt6_info *rt)
1035
1036 {
1037         struct sk_buff *skb;
1038         struct frag_hdr fhdr;
1039         int err;
1040
1041         /* There is support for UDP large send offload by network
1042          * device, so create one single skb packet containing complete
1043          * udp datagram
1044          */
1045         skb = skb_peek_tail(&sk->sk_write_queue);
1046         if (skb == NULL) {
1047                 skb = sock_alloc_send_skb(sk,
1048                         hh_len + fragheaderlen + transhdrlen + 20,
1049                         (flags & MSG_DONTWAIT), &err);
1050                 if (skb == NULL)
1051                         return err;
1052
1053                 /* reserve space for Hardware header */
1054                 skb_reserve(skb, hh_len);
1055
1056                 /* create space for UDP/IP header */
1057                 skb_put(skb, fragheaderlen + transhdrlen);
1058
1059                 /* initialize network header pointer */
1060                 skb_reset_network_header(skb);
1061
1062                 /* initialize protocol header pointer */
1063                 skb->transport_header = skb->network_header + fragheaderlen;
1064
1065                 skb->protocol = htons(ETH_P_IPV6);
1066                 skb->csum = 0;
1067
1068                 __skb_queue_tail(&sk->sk_write_queue, skb);
1069         } else if (skb_is_gso(skb)) {
1070                 goto append;
1071         }
1072
1073         skb->ip_summed = CHECKSUM_PARTIAL;
1074         /* Specify the length of each IPv6 datagram fragment.
1075          * It has to be a multiple of 8.
1076          */
1077         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1078                                      sizeof(struct frag_hdr)) & ~7;
1079         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1080         ipv6_select_ident(&fhdr, rt);
1081         skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1082
1083 append:
1084         return skb_append_datato_frags(sk, skb, getfrag, from,
1085                                        (length - transhdrlen));
1086 }
1087
1088 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1089                                                gfp_t gfp)
1090 {
1091         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1092 }
1093
1094 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1095                                                 gfp_t gfp)
1096 {
1097         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1098 }
1099
1100 static void ip6_append_data_mtu(unsigned int *mtu,
1101                                 int *maxfraglen,
1102                                 unsigned int fragheaderlen,
1103                                 struct sk_buff *skb,
1104                                 struct rt6_info *rt,
1105                                 unsigned int orig_mtu)
1106 {
1107         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1108                 if (skb == NULL) {
1109                         /* first fragment, reserve header_len */
1110                         *mtu = orig_mtu - rt->dst.header_len;
1111
1112                 } else {
1113                         /*
1114                          * this fragment is not first, the headers
1115                          * space is regarded as data space.
1116                          */
1117                         *mtu = orig_mtu;
1118                 }
1119                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1120                               + fragheaderlen - sizeof(struct frag_hdr);
1121         }
1122 }
1123
1124 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1125         int offset, int len, int odd, struct sk_buff *skb),
1126         void *from, int length, int transhdrlen,
1127         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1128         struct rt6_info *rt, unsigned int flags, int dontfrag)
1129 {
1130         struct inet_sock *inet = inet_sk(sk);
1131         struct ipv6_pinfo *np = inet6_sk(sk);
1132         struct inet_cork *cork;
1133         struct sk_buff *skb, *skb_prev = NULL;
1134         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1135         int exthdrlen;
1136         int dst_exthdrlen;
1137         int hh_len;
1138         int copy;
1139         int err;
1140         int offset = 0;
1141         __u8 tx_flags = 0;
1142         u32 tskey = 0;
1143
1144         if (flags&MSG_PROBE)
1145                 return 0;
1146         cork = &inet->cork.base;
1147         if (skb_queue_empty(&sk->sk_write_queue)) {
1148                 /*
1149                  * setup for corking
1150                  */
1151                 if (opt) {
1152                         if (WARN_ON(np->cork.opt))
1153                                 return -EINVAL;
1154
1155                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1156                         if (unlikely(np->cork.opt == NULL))
1157                                 return -ENOBUFS;
1158
1159                         np->cork.opt->tot_len = opt->tot_len;
1160                         np->cork.opt->opt_flen = opt->opt_flen;
1161                         np->cork.opt->opt_nflen = opt->opt_nflen;
1162
1163                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1164                                                             sk->sk_allocation);
1165                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1166                                 return -ENOBUFS;
1167
1168                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1169                                                             sk->sk_allocation);
1170                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1171                                 return -ENOBUFS;
1172
1173                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1174                                                            sk->sk_allocation);
1175                         if (opt->hopopt && !np->cork.opt->hopopt)
1176                                 return -ENOBUFS;
1177
1178                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1179                                                             sk->sk_allocation);
1180                         if (opt->srcrt && !np->cork.opt->srcrt)
1181                                 return -ENOBUFS;
1182
1183                         /* need source address above miyazawa*/
1184                 }
1185                 dst_hold(&rt->dst);
1186                 cork->dst = &rt->dst;
1187                 inet->cork.fl.u.ip6 = *fl6;
1188                 np->cork.hop_limit = hlimit;
1189                 np->cork.tclass = tclass;
1190                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1191                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1192                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1193                 else
1194                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1195                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1196                 if (np->frag_size < mtu) {
1197                         if (np->frag_size)
1198                                 mtu = np->frag_size;
1199                 }
1200                 cork->fragsize = mtu;
1201                 if (dst_allfrag(rt->dst.path))
1202                         cork->flags |= IPCORK_ALLFRAG;
1203                 cork->length = 0;
1204                 exthdrlen = (opt ? opt->opt_flen : 0);
1205                 length += exthdrlen;
1206                 transhdrlen += exthdrlen;
1207                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1208         } else {
1209                 rt = (struct rt6_info *)cork->dst;
1210                 fl6 = &inet->cork.fl.u.ip6;
1211                 opt = np->cork.opt;
1212                 transhdrlen = 0;
1213                 exthdrlen = 0;
1214                 dst_exthdrlen = 0;
1215                 mtu = cork->fragsize;
1216         }
1217         orig_mtu = mtu;
1218
1219         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1220
1221         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1222                         (opt ? opt->opt_nflen : 0);
1223         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1224                      sizeof(struct frag_hdr);
1225
1226         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1227                 unsigned int maxnonfragsize, headersize;
1228
1229                 headersize = sizeof(struct ipv6hdr) +
1230                              (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1231                              (dst_allfrag(&rt->dst) ?
1232                               sizeof(struct frag_hdr) : 0) +
1233                              rt->rt6i_nfheader_len;
1234
1235                 if (ip6_sk_ignore_df(sk))
1236                         maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1237                 else
1238                         maxnonfragsize = mtu;
1239
1240                 /* dontfrag active */
1241                 if ((cork->length + length > mtu - headersize) && dontfrag &&
1242                     (sk->sk_protocol == IPPROTO_UDP ||
1243                      sk->sk_protocol == IPPROTO_RAW)) {
1244                         ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1245                                                    sizeof(struct ipv6hdr));
1246                         goto emsgsize;
1247                 }
1248
1249                 if (cork->length + length > maxnonfragsize - headersize) {
1250 emsgsize:
1251                         ipv6_local_error(sk, EMSGSIZE, fl6,
1252                                          mtu - headersize +
1253                                          sizeof(struct ipv6hdr));
1254                         return -EMSGSIZE;
1255                 }
1256         }
1257
1258         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1259                 sock_tx_timestamp(sk, &tx_flags);
1260                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1261                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1262                         tskey = sk->sk_tskey++;
1263         }
1264
1265         /*
1266          * Let's try using as much space as possible.
1267          * Use MTU if total length of the message fits into the MTU.
1268          * Otherwise, we need to reserve fragment header and
1269          * fragment alignment (= 8-15 octects, in total).
1270          *
1271          * Note that we may need to "move" the data from the tail of
1272          * of the buffer to the new fragment when we split
1273          * the message.
1274          *
1275          * FIXME: It may be fragmented into multiple chunks
1276          *        at once if non-fragmentable extension headers
1277          *        are too large.
1278          * --yoshfuji
1279          */
1280
1281         skb = skb_peek_tail(&sk->sk_write_queue);
1282         cork->length += length;
1283         if (((length > mtu) ||
1284              (skb && skb_is_gso(skb))) &&
1285             (sk->sk_protocol == IPPROTO_UDP) &&
1286             (rt->dst.dev->features & NETIF_F_UFO)) {
1287                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1288                                           hh_len, fragheaderlen,
1289                                           transhdrlen, mtu, flags, rt);
1290                 if (err)
1291                         goto error;
1292                 return 0;
1293         }
1294
1295         if (!skb)
1296                 goto alloc_new_skb;
1297
1298         while (length > 0) {
1299                 /* Check if the remaining data fits into current packet. */
1300                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1301                 if (copy < length)
1302                         copy = maxfraglen - skb->len;
1303
1304                 if (copy <= 0) {
1305                         char *data;
1306                         unsigned int datalen;
1307                         unsigned int fraglen;
1308                         unsigned int fraggap;
1309                         unsigned int alloclen;
1310 alloc_new_skb:
1311                         /* There's no room in the current skb */
1312                         if (skb)
1313                                 fraggap = skb->len - maxfraglen;
1314                         else
1315                                 fraggap = 0;
1316                         /* update mtu and maxfraglen if necessary */
1317                         if (skb == NULL || skb_prev == NULL)
1318                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1319                                                     fragheaderlen, skb, rt,
1320                                                     orig_mtu);
1321
1322                         skb_prev = skb;
1323
1324                         /*
1325                          * If remaining data exceeds the mtu,
1326                          * we know we need more fragment(s).
1327                          */
1328                         datalen = length + fraggap;
1329
1330                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1331                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1332                         if ((flags & MSG_MORE) &&
1333                             !(rt->dst.dev->features&NETIF_F_SG))
1334                                 alloclen = mtu;
1335                         else
1336                                 alloclen = datalen + fragheaderlen;
1337
1338                         alloclen += dst_exthdrlen;
1339
1340                         if (datalen != length + fraggap) {
1341                                 /*
1342                                  * this is not the last fragment, the trailer
1343                                  * space is regarded as data space.
1344                                  */
1345                                 datalen += rt->dst.trailer_len;
1346                         }
1347
1348                         alloclen += rt->dst.trailer_len;
1349                         fraglen = datalen + fragheaderlen;
1350
1351                         /*
1352                          * We just reserve space for fragment header.
1353                          * Note: this may be overallocation if the message
1354                          * (without MSG_MORE) fits into the MTU.
1355                          */
1356                         alloclen += sizeof(struct frag_hdr);
1357
1358                         if (transhdrlen) {
1359                                 skb = sock_alloc_send_skb(sk,
1360                                                 alloclen + hh_len,
1361                                                 (flags & MSG_DONTWAIT), &err);
1362                         } else {
1363                                 skb = NULL;
1364                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1365                                     2 * sk->sk_sndbuf)
1366                                         skb = sock_wmalloc(sk,
1367                                                            alloclen + hh_len, 1,
1368                                                            sk->sk_allocation);
1369                                 if (unlikely(skb == NULL))
1370                                         err = -ENOBUFS;
1371                         }
1372                         if (skb == NULL)
1373                                 goto error;
1374                         /*
1375                          *      Fill in the control structures
1376                          */
1377                         skb->protocol = htons(ETH_P_IPV6);
1378                         skb->ip_summed = CHECKSUM_NONE;
1379                         skb->csum = 0;
1380                         /* reserve for fragmentation and ipsec header */
1381                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1382                                     dst_exthdrlen);
1383
1384                         /* Only the initial fragment is time stamped */
1385                         skb_shinfo(skb)->tx_flags = tx_flags;
1386                         tx_flags = 0;
1387                         skb_shinfo(skb)->tskey = tskey;
1388                         tskey = 0;
1389
1390                         /*
1391                          *      Find where to start putting bytes
1392                          */
1393                         data = skb_put(skb, fraglen);
1394                         skb_set_network_header(skb, exthdrlen);
1395                         data += fragheaderlen;
1396                         skb->transport_header = (skb->network_header +
1397                                                  fragheaderlen);
1398                         if (fraggap) {
1399                                 skb->csum = skb_copy_and_csum_bits(
1400                                         skb_prev, maxfraglen,
1401                                         data + transhdrlen, fraggap, 0);
1402                                 skb_prev->csum = csum_sub(skb_prev->csum,
1403                                                           skb->csum);
1404                                 data += fraggap;
1405                                 pskb_trim_unique(skb_prev, maxfraglen);
1406                         }
1407                         copy = datalen - transhdrlen - fraggap;
1408
1409                         if (copy < 0) {
1410                                 err = -EINVAL;
1411                                 kfree_skb(skb);
1412                                 goto error;
1413                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1414                                 err = -EFAULT;
1415                                 kfree_skb(skb);
1416                                 goto error;
1417                         }
1418
1419                         offset += copy;
1420                         length -= datalen - fraggap;
1421                         transhdrlen = 0;
1422                         exthdrlen = 0;
1423                         dst_exthdrlen = 0;
1424
1425                         /*
1426                          * Put the packet on the pending queue
1427                          */
1428                         __skb_queue_tail(&sk->sk_write_queue, skb);
1429                         continue;
1430                 }
1431
1432                 if (copy > length)
1433                         copy = length;
1434
1435                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1436                         unsigned int off;
1437
1438                         off = skb->len;
1439                         if (getfrag(from, skb_put(skb, copy),
1440                                                 offset, copy, off, skb) < 0) {
1441                                 __skb_trim(skb, off);
1442                                 err = -EFAULT;
1443                                 goto error;
1444                         }
1445                 } else {
1446                         int i = skb_shinfo(skb)->nr_frags;
1447                         struct page_frag *pfrag = sk_page_frag(sk);
1448
1449                         err = -ENOMEM;
1450                         if (!sk_page_frag_refill(sk, pfrag))
1451                                 goto error;
1452
1453                         if (!skb_can_coalesce(skb, i, pfrag->page,
1454                                               pfrag->offset)) {
1455                                 err = -EMSGSIZE;
1456                                 if (i == MAX_SKB_FRAGS)
1457                                         goto error;
1458
1459                                 __skb_fill_page_desc(skb, i, pfrag->page,
1460                                                      pfrag->offset, 0);
1461                                 skb_shinfo(skb)->nr_frags = ++i;
1462                                 get_page(pfrag->page);
1463                         }
1464                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1465                         if (getfrag(from,
1466                                     page_address(pfrag->page) + pfrag->offset,
1467                                     offset, copy, skb->len, skb) < 0)
1468                                 goto error_efault;
1469
1470                         pfrag->offset += copy;
1471                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1472                         skb->len += copy;
1473                         skb->data_len += copy;
1474                         skb->truesize += copy;
1475                         atomic_add(copy, &sk->sk_wmem_alloc);
1476                 }
1477                 offset += copy;
1478                 length -= copy;
1479         }
1480
1481         return 0;
1482
1483 error_efault:
1484         err = -EFAULT;
1485 error:
1486         cork->length -= length;
1487         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1488         return err;
1489 }
1490 EXPORT_SYMBOL_GPL(ip6_append_data);
1491
1492 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1493 {
1494         if (np->cork.opt) {
1495                 kfree(np->cork.opt->dst0opt);
1496                 kfree(np->cork.opt->dst1opt);
1497                 kfree(np->cork.opt->hopopt);
1498                 kfree(np->cork.opt->srcrt);
1499                 kfree(np->cork.opt);
1500                 np->cork.opt = NULL;
1501         }
1502
1503         if (inet->cork.base.dst) {
1504                 dst_release(inet->cork.base.dst);
1505                 inet->cork.base.dst = NULL;
1506                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1507         }
1508         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1509 }
1510
1511 int ip6_push_pending_frames(struct sock *sk)
1512 {
1513         struct sk_buff *skb, *tmp_skb;
1514         struct sk_buff **tail_skb;
1515         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1516         struct inet_sock *inet = inet_sk(sk);
1517         struct ipv6_pinfo *np = inet6_sk(sk);
1518         struct net *net = sock_net(sk);
1519         struct ipv6hdr *hdr;
1520         struct ipv6_txoptions *opt = np->cork.opt;
1521         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1522         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1523         unsigned char proto = fl6->flowi6_proto;
1524         int err = 0;
1525
1526         skb = __skb_dequeue(&sk->sk_write_queue);
1527         if (skb == NULL)
1528                 goto out;
1529         tail_skb = &(skb_shinfo(skb)->frag_list);
1530
1531         /* move skb->data to ip header from ext header */
1532         if (skb->data < skb_network_header(skb))
1533                 __skb_pull(skb, skb_network_offset(skb));
1534         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1535                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1536                 *tail_skb = tmp_skb;
1537                 tail_skb = &(tmp_skb->next);
1538                 skb->len += tmp_skb->len;
1539                 skb->data_len += tmp_skb->len;
1540                 skb->truesize += tmp_skb->truesize;
1541                 tmp_skb->destructor = NULL;
1542                 tmp_skb->sk = NULL;
1543         }
1544
1545         /* Allow local fragmentation. */
1546         skb->ignore_df = ip6_sk_ignore_df(sk);
1547
1548         *final_dst = fl6->daddr;
1549         __skb_pull(skb, skb_network_header_len(skb));
1550         if (opt && opt->opt_flen)
1551                 ipv6_push_frag_opts(skb, opt, &proto);
1552         if (opt && opt->opt_nflen)
1553                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1554
1555         skb_push(skb, sizeof(struct ipv6hdr));
1556         skb_reset_network_header(skb);
1557         hdr = ipv6_hdr(skb);
1558
1559         ip6_flow_hdr(hdr, np->cork.tclass,
1560                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1561                                         np->autoflowlabel));
1562         hdr->hop_limit = np->cork.hop_limit;
1563         hdr->nexthdr = proto;
1564         hdr->saddr = fl6->saddr;
1565         hdr->daddr = *final_dst;
1566
1567         skb->priority = sk->sk_priority;
1568         skb->mark = sk->sk_mark;
1569
1570         skb_dst_set(skb, dst_clone(&rt->dst));
1571         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1572         if (proto == IPPROTO_ICMPV6) {
1573                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1574
1575                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1576                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1577         }
1578
1579         err = ip6_local_out(skb);
1580         if (err) {
1581                 if (err > 0)
1582                         err = net_xmit_errno(err);
1583                 if (err)
1584                         goto error;
1585         }
1586
1587 out:
1588         ip6_cork_release(inet, np);
1589         return err;
1590 error:
1591         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1592         goto out;
1593 }
1594 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1595
1596 void ip6_flush_pending_frames(struct sock *sk)
1597 {
1598         struct sk_buff *skb;
1599
1600         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1601                 if (skb_dst(skb))
1602                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1603                                       IPSTATS_MIB_OUTDISCARDS);
1604                 kfree_skb(skb);
1605         }
1606
1607         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1608 }
1609 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);