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 #include <net/l3mdev.h>
  59
  60 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
  61 {
  62         struct dst_entry *dst = skb_dst(skb);
  63         struct net_device *dev = dst->dev;
  64         struct neighbour *neigh;
  65         struct in6_addr *nexthop;
  66         int ret;
  67
  68         skb->protocol = htons(ETH_P_IPV6);
  69         skb->dev = dev;
  70
  71         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
  72                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
  73
  74                 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
  75                     ((mroute6_socket(net, skb) &&
  76                      !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
  77                      ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
  78                                          &ipv6_hdr(skb)->saddr))) {
  79                         struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  80
  81                         /* Do not check for IFF_ALLMULTI; multicast routing
  82                            is not supported in any case.
  83                          */
  84                         if (newskb)
  85                                 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  86                                         net, sk, newskb, NULL, newskb->dev,
  87                                         dev_loopback_xmit);
  88
  89                         if (ipv6_hdr(skb)->hop_limit == 0) {
  90                                 IP6_INC_STATS(net, idev,
  91                                               IPSTATS_MIB_OUTDISCARDS);
  92                                 kfree_skb(skb);
  93                                 return 0;
  94                         }
  95                 }
  96
  97                 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
  98
  99                 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
 100                     IPV6_ADDR_SCOPE_NODELOCAL &&
 101                     !(dev->flags & IFF_LOOPBACK)) {
 102                         kfree_skb(skb);
 103                         return 0;
 104                 }
 105         }
 106
 107         rcu_read_lock_bh();
 108         nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
 109         neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
 110         if (unlikely(!neigh))
 111                 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
 112         if (!IS_ERR(neigh)) {
 113                 ret = dst_neigh_output(dst, neigh, skb);
 114                 rcu_read_unlock_bh();
 115                 return ret;
 116         }
 117         rcu_read_unlock_bh();
 118
 119         IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 120         kfree_skb(skb);
 121         return -EINVAL;
 122 }
 123
 124 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 125 {
 126         if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
 127             dst_allfrag(skb_dst(skb)) ||
 128             (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 129                 return ip6_fragment(net, sk, skb, ip6_finish_output2);
 130         else
 131                 return ip6_finish_output2(net, sk, skb);
 132 }
 133
 134 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 135 {
 136         struct net_device *dev = skb_dst(skb)->dev;
 137         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 138
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
 141                 kfree_skb(skb);
 142                 return 0;
 143         }
 144
 145         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
 146                             net, sk, 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  * Note : socket lock is not held for SYNACK packets, but might be modified
 154  * by calls to skb_set_owner_w() and ipv6_local_error(),
 155  * which are using proper atomic operations or spinlocks.
 156  */
 157 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 158              struct ipv6_txoptions *opt, int tclass)
 159 {
 160         struct net *net = sock_net(sk);
 161         const struct ipv6_pinfo *np = inet6_sk(sk);
 162         struct in6_addr *first_hop = &fl6->daddr;
 163         struct dst_entry *dst = skb_dst(skb);
 164         struct ipv6hdr *hdr;
 165         u8  proto = fl6->flowi6_proto;
 166         int seg_len = skb->len;
 167         int hlimit = -1;
 168         u32 mtu;
 169
 170         if (opt) {
 171                 unsigned int head_room;
 172
 173                 /* First: exthdrs may take lots of space (~8K for now)
 174                    MAX_HEADER is not enough.
 175                  */
 176                 head_room = opt->opt_nflen + opt->opt_flen;
 177                 seg_len += head_room;
 178                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 179
 180                 if (skb_headroom(skb) < head_room) {
 181                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 182                         if (!skb2) {
 183                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 184                                               IPSTATS_MIB_OUTDISCARDS);
 185                                 kfree_skb(skb);
 186                                 return -ENOBUFS;
 187                         }
 188                         consume_skb(skb);
 189                         skb = skb2;
 190                         /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically,
 191                          * it is safe to call in our context (socket lock not held)
 192                          */
 193                         skb_set_owner_w(skb, (struct sock *)sk);
 194                 }
 195                 if (opt->opt_flen)
 196                         ipv6_push_frag_opts(skb, opt, &proto);
 197                 if (opt->opt_nflen)
 198                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 199         }
 200
 201         skb_push(skb, sizeof(struct ipv6hdr));
 202         skb_reset_network_header(skb);
 203         hdr = ipv6_hdr(skb);
 204
 205         /*
 206          *      Fill in the IPv6 header
 207          */
 208         if (np)
 209                 hlimit = np->hop_limit;
 210         if (hlimit < 0)
 211                 hlimit = ip6_dst_hoplimit(dst);
 212
 213         ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
 214                                                      np->autoflowlabel, fl6));
 215
 216         hdr->payload_len = htons(seg_len);
 217         hdr->nexthdr = proto;
 218         hdr->hop_limit = hlimit;
 219
 220         hdr->saddr = fl6->saddr;
 221         hdr->daddr = *first_hop;
 222
 223         skb->protocol = htons(ETH_P_IPV6);
 224         skb->priority = sk->sk_priority;
 225         skb->mark = sk->sk_mark;
 226
 227         mtu = dst_mtu(dst);
 228         if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 229                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 230                               IPSTATS_MIB_OUT, skb->len);
 231                 /* hooks should never assume socket lock is held.
 232                  * we promote our socket to non const
 233                  */
 234                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 235                                net, (struct sock *)sk, skb, NULL, dst->dev,
 236                                dst_output);
 237         }
 238
 239         skb->dev = dst->dev;
 240         /* ipv6_local_error() does not require socket lock,
 241          * we promote our socket to non const
 242          */
 243         ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
 244
 245         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 246         kfree_skb(skb);
 247         return -EMSGSIZE;
 248 }
 249 EXPORT_SYMBOL(ip6_xmit);
 250
 251 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 252 {
 253         struct ip6_ra_chain *ra;
 254         struct sock *last = NULL;
 255
 256         read_lock(&ip6_ra_lock);
 257         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 258                 struct sock *sk = ra->sk;
 259                 if (sk && ra->sel == sel &&
 260                     (!sk->sk_bound_dev_if ||
 261                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 262                         if (last) {
 263                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 264                                 if (skb2)
 265                                         rawv6_rcv(last, skb2);
 266                         }
 267                         last = sk;
 268                 }
 269         }
 270
 271         if (last) {
 272                 rawv6_rcv(last, skb);
 273                 read_unlock(&ip6_ra_lock);
 274                 return 1;
 275         }
 276         read_unlock(&ip6_ra_lock);
 277         return 0;
 278 }
 279
 280 static int ip6_forward_proxy_check(struct sk_buff *skb)
 281 {
 282         struct ipv6hdr *hdr = ipv6_hdr(skb);
 283         u8 nexthdr = hdr->nexthdr;
 284         __be16 frag_off;
 285         int offset;
 286
 287         if (ipv6_ext_hdr(nexthdr)) {
 288                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 289                 if (offset < 0)
 290                         return 0;
 291         } else
 292                 offset = sizeof(struct ipv6hdr);
 293
 294         if (nexthdr == IPPROTO_ICMPV6) {
 295                 struct icmp6hdr *icmp6;
 296
 297                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 298                                          offset + 1 - skb->data)))
 299                         return 0;
 300
 301                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 302
 303                 switch (icmp6->icmp6_type) {
 304                 case NDISC_ROUTER_SOLICITATION:
 305                 case NDISC_ROUTER_ADVERTISEMENT:
 306                 case NDISC_NEIGHBOUR_SOLICITATION:
 307                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 308                 case NDISC_REDIRECT:
 309                         /* For reaction involving unicast neighbor discovery
 310                          * message destined to the proxied address, pass it to
 311                          * input function.
 312                          */
 313                         return 1;
 314                 default:
 315                         break;
 316                 }
 317         }
 318
 319         /*
 320          * The proxying router can't forward traffic sent to a link-local
 321          * address, so signal the sender and discard the packet. This
 322          * behavior is clarified by the MIPv6 specification.
 323          */
 324         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 325                 dst_link_failure(skb);
 326                 return -1;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static inline int ip6_forward_finish(struct net *net, struct sock *sk,
 333                                      struct sk_buff *skb)
 334 {
 335         skb_sender_cpu_clear(skb);
 336         return dst_output(net, sk, skb);
 337 }
 338
 339 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 340 {
 341         unsigned int mtu;
 342         struct inet6_dev *idev;
 343
 344         if (dst_metric_locked(dst, RTAX_MTU)) {
 345                 mtu = dst_metric_raw(dst, RTAX_MTU);
 346                 if (mtu)
 347                         return mtu;
 348         }
 349
 350         mtu = IPV6_MIN_MTU;
 351         rcu_read_lock();
 352         idev = __in6_dev_get(dst->dev);
 353         if (idev)
 354                 mtu = idev->cnf.mtu6;
 355         rcu_read_unlock();
 356
 357         return mtu;
 358 }
 359
 360 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 361 {
 362         if (skb->len <= mtu)
 363                 return false;
 364
 365         /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
 366         if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
 367                 return true;
 368
 369         if (skb->ignore_df)
 370                 return false;
 371
 372         if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
 373                 return false;
 374
 375         return true;
 376 }
 377
 378 int ip6_forward(struct sk_buff *skb)
 379 {
 380         struct dst_entry *dst = skb_dst(skb);
 381         struct ipv6hdr *hdr = ipv6_hdr(skb);
 382         struct inet6_skb_parm *opt = IP6CB(skb);
 383         struct net *net = dev_net(dst->dev);
 384         u32 mtu;
 385
 386         if (net->ipv6.devconf_all->forwarding == 0)
 387                 goto error;
 388
 389         if (skb->pkt_type != PACKET_HOST)
 390                 goto drop;
 391
 392         if (unlikely(skb->sk))
 393                 goto drop;
 394
 395         if (skb_warn_if_lro(skb))
 396                 goto drop;
 397
 398         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 399                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 400                                  IPSTATS_MIB_INDISCARDS);
 401                 goto drop;
 402         }
 403
 404         skb_forward_csum(skb);
 405
 406         /*
 407          *      We DO NOT make any processing on
 408          *      RA packets, pushing them to user level AS IS
 409          *      without ane WARRANTY that application will be able
 410          *      to interpret them. The reason is that we
 411          *      cannot make anything clever here.
 412          *
 413          *      We are not end-node, so that if packet contains
 414          *      AH/ESP, we cannot make anything.
 415          *      Defragmentation also would be mistake, RA packets
 416          *      cannot be fragmented, because there is no warranty
 417          *      that different fragments will go along one path. --ANK
 418          */
 419         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 420                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 421                         return 0;
 422         }
 423
 424         /*
 425          *      check and decrement ttl
 426          */
 427         if (hdr->hop_limit <= 1) {
 428                 /* Force OUTPUT device used as source address */
 429                 skb->dev = dst->dev;
 430                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 431                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 432                                  IPSTATS_MIB_INHDRERRORS);
 433
 434                 kfree_skb(skb);
 435                 return -ETIMEDOUT;
 436         }
 437
 438         /* XXX: idev->cnf.proxy_ndp? */
 439         if (net->ipv6.devconf_all->proxy_ndp &&
 440             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 441                 int proxied = ip6_forward_proxy_check(skb);
 442                 if (proxied > 0)
 443                         return ip6_input(skb);
 444                 else if (proxied < 0) {
 445                         IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 446                                          IPSTATS_MIB_INDISCARDS);
 447                         goto drop;
 448                 }
 449         }
 450
 451         if (!xfrm6_route_forward(skb)) {
 452                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 453                                  IPSTATS_MIB_INDISCARDS);
 454                 goto drop;
 455         }
 456         dst = skb_dst(skb);
 457
 458         /* IPv6 specs say nothing about it, but it is clear that we cannot
 459            send redirects to source routed frames.
 460            We don't send redirects to frames decapsulated from IPsec.
 461          */
 462         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 463                 struct in6_addr *target = NULL;
 464                 struct inet_peer *peer;
 465                 struct rt6_info *rt;
 466
 467                 /*
 468                  *      incoming and outgoing devices are the same
 469                  *      send a redirect.
 470                  */
 471
 472                 rt = (struct rt6_info *) dst;
 473                 if (rt->rt6i_flags & RTF_GATEWAY)
 474                         target = &rt->rt6i_gateway;
 475                 else
 476                         target = &hdr->daddr;
 477
 478                 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
 479
 480                 /* Limit redirects both by destination (here)
 481                    and by source (inside ndisc_send_redirect)
 482                  */
 483                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 484                         ndisc_send_redirect(skb, target);
 485                 if (peer)
 486                         inet_putpeer(peer);
 487         } else {
 488                 int addrtype = ipv6_addr_type(&hdr->saddr);
 489
 490                 /* This check is security critical. */
 491                 if (addrtype == IPV6_ADDR_ANY ||
 492                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 493                         goto error;
 494                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 495                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 496                                     ICMPV6_NOT_NEIGHBOUR, 0);
 497                         goto error;
 498                 }
 499         }
 500
 501         mtu = ip6_dst_mtu_forward(dst);
 502         if (mtu < IPV6_MIN_MTU)
 503                 mtu = IPV6_MIN_MTU;
 504
 505         if (ip6_pkt_too_big(skb, mtu)) {
 506                 /* Again, force OUTPUT device used as source address */
 507                 skb->dev = dst->dev;
 508                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 509                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 510                                  IPSTATS_MIB_INTOOBIGERRORS);
 511                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 512                                  IPSTATS_MIB_FRAGFAILS);
 513                 kfree_skb(skb);
 514                 return -EMSGSIZE;
 515         }
 516
 517         if (skb_cow(skb, dst->dev->hard_header_len)) {
 518                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 519                                  IPSTATS_MIB_OUTDISCARDS);
 520                 goto drop;
 521         }
 522
 523         hdr = ipv6_hdr(skb);
 524
 525         /* Mangling hops number delayed to point after skb COW */
 526
 527         hdr->hop_limit--;
 528
 529         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 530         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 531         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
 532                        net, NULL, skb, skb->dev, dst->dev,
 533                        ip6_forward_finish);
 534
 535 error:
 536         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 537 drop:
 538         kfree_skb(skb);
 539         return -EINVAL;
 540 }
 541
 542 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 543 {
 544         to->pkt_type = from->pkt_type;
 545         to->priority = from->priority;
 546         to->protocol = from->protocol;
 547         skb_dst_drop(to);
 548         skb_dst_set(to, dst_clone(skb_dst(from)));
 549         to->dev = from->dev;
 550         to->mark = from->mark;
 551
 552 #ifdef CONFIG_NET_SCHED
 553         to->tc_index = from->tc_index;
 554 #endif
 555         nf_copy(to, from);
 556         skb_copy_secmark(to, from);
 557 }
 558
 559 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 560                  int (*output)(struct net *, struct sock *, struct sk_buff *))
 561 {
 562         struct sk_buff *frag;
 563         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 564         struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
 565                                 inet6_sk(skb->sk) : NULL;
 566         struct ipv6hdr *tmp_hdr;
 567         struct frag_hdr *fh;
 568         unsigned int mtu, hlen, left, len;
 569         int hroom, troom;
 570         __be32 frag_id;
 571         int ptr, offset = 0, err = 0;
 572         u8 *prevhdr, nexthdr = 0;
 573
 574         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 575         nexthdr = *prevhdr;
 576
 577         mtu = ip6_skb_dst_mtu(skb);
 578
 579         /* We must not fragment if the socket is set to force MTU discovery
 580          * or if the skb it not generated by a local socket.
 581          */
 582         if (unlikely(!skb->ignore_df && skb->len > mtu))
 583                 goto fail_toobig;
 584
 585         if (IP6CB(skb)->frag_max_size) {
 586                 if (IP6CB(skb)->frag_max_size > mtu)
 587                         goto fail_toobig;
 588
 589                 /* don't send fragments larger than what we received */
 590                 mtu = IP6CB(skb)->frag_max_size;
 591                 if (mtu < IPV6_MIN_MTU)
 592                         mtu = IPV6_MIN_MTU;
 593         }
 594
 595         if (np && np->frag_size < mtu) {
 596                 if (np->frag_size)
 597                         mtu = np->frag_size;
 598         }
 599         if (mtu < hlen + sizeof(struct frag_hdr) + 8)
 600                 goto fail_toobig;
 601         mtu -= hlen + sizeof(struct frag_hdr);
 602
 603         frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
 604                                     &ipv6_hdr(skb)->saddr);
 605
 606         if (skb->ip_summed == CHECKSUM_PARTIAL &&
 607             (err = skb_checksum_help(skb)))
 608                 goto fail;
 609
 610         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 611         if (skb_has_frag_list(skb)) {
 612                 int first_len = skb_pagelen(skb);
 613                 struct sk_buff *frag2;
 614
 615                 if (first_len - hlen > mtu ||
 616                     ((first_len - hlen) & 7) ||
 617                     skb_cloned(skb) ||
 618                     skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
 619                         goto slow_path;
 620
 621                 skb_walk_frags(skb, frag) {
 622                         /* Correct geometry. */
 623                         if (frag->len > mtu ||
 624                             ((frag->len & 7) && frag->next) ||
 625                             skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
 626                                 goto slow_path_clean;
 627
 628                         /* Partially cloned skb? */
 629                         if (skb_shared(frag))
 630                                 goto slow_path_clean;
 631
 632                         BUG_ON(frag->sk);
 633                         if (skb->sk) {
 634                                 frag->sk = skb->sk;
 635                                 frag->destructor = sock_wfree;
 636                         }
 637                         skb->truesize -= frag->truesize;
 638                 }
 639
 640                 err = 0;
 641                 offset = 0;
 642                 /* BUILD HEADER */
 643
 644                 *prevhdr = NEXTHDR_FRAGMENT;
 645                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 646                 if (!tmp_hdr) {
 647                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 648                                       IPSTATS_MIB_FRAGFAILS);
 649                         err = -ENOMEM;
 650                         goto fail;
 651                 }
 652                 frag = skb_shinfo(skb)->frag_list;
 653                 skb_frag_list_init(skb);
 654
 655                 __skb_pull(skb, hlen);
 656                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 657                 __skb_push(skb, hlen);
 658                 skb_reset_network_header(skb);
 659                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 660
 661                 fh->nexthdr = nexthdr;
 662                 fh->reserved = 0;
 663                 fh->frag_off = htons(IP6_MF);
 664                 fh->identification = frag_id;
 665
 666                 first_len = skb_pagelen(skb);
 667                 skb->data_len = first_len - skb_headlen(skb);
 668                 skb->len = first_len;
 669                 ipv6_hdr(skb)->payload_len = htons(first_len -
 670                                                    sizeof(struct ipv6hdr));
 671
 672                 dst_hold(&rt->dst);
 673
 674                 for (;;) {
 675                         /* Prepare header of the next frame,
 676                          * before previous one went down. */
 677                         if (frag) {
 678                                 frag->ip_summed = CHECKSUM_NONE;
 679                                 skb_reset_transport_header(frag);
 680                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 681                                 __skb_push(frag, hlen);
 682                                 skb_reset_network_header(frag);
 683                                 memcpy(skb_network_header(frag), tmp_hdr,
 684                                        hlen);
 685                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 686                                 fh->nexthdr = nexthdr;
 687                                 fh->reserved = 0;
 688                                 fh->frag_off = htons(offset);
 689                                 if (frag->next)
 690                                         fh->frag_off |= htons(IP6_MF);
 691                                 fh->identification = frag_id;
 692                                 ipv6_hdr(frag)->payload_len =
 693                                                 htons(frag->len -
 694                                                       sizeof(struct ipv6hdr));
 695                                 ip6_copy_metadata(frag, skb);
 696                         }
 697
 698                         err = output(net, sk, skb);
 699                         if (!err)
 700                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 701                                               IPSTATS_MIB_FRAGCREATES);
 702
 703                         if (err || !frag)
 704                                 break;
 705
 706                         skb = frag;
 707                         frag = skb->next;
 708                         skb->next = NULL;
 709                 }
 710
 711                 kfree(tmp_hdr);
 712
 713                 if (err == 0) {
 714                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 715                                       IPSTATS_MIB_FRAGOKS);
 716                         ip6_rt_put(rt);
 717                         return 0;
 718                 }
 719
 720                 kfree_skb_list(frag);
 721
 722                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 723                               IPSTATS_MIB_FRAGFAILS);
 724                 ip6_rt_put(rt);
 725                 return err;
 726
 727 slow_path_clean:
 728                 skb_walk_frags(skb, frag2) {
 729                         if (frag2 == frag)
 730                                 break;
 731                         frag2->sk = NULL;
 732                         frag2->destructor = NULL;
 733                         skb->truesize += frag2->truesize;
 734                 }
 735         }
 736
 737 slow_path:
 738         left = skb->len - hlen;         /* Space per frame */
 739         ptr = hlen;                     /* Where to start from */
 740
 741         /*
 742          *      Fragment the datagram.
 743          */
 744
 745         *prevhdr = NEXTHDR_FRAGMENT;
 746         troom = rt->dst.dev->needed_tailroom;
 747
 748         /*
 749          *      Keep copying data until we run out.
 750          */
 751         while (left > 0)        {
 752                 len = left;
 753                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 754                 if (len > mtu)
 755                         len = mtu;
 756                 /* IF: we are not sending up to and including the packet end
 757                    then align the next start on an eight byte boundary */
 758                 if (len < left) {
 759                         len &= ~7;
 760                 }
 761
 762                 /* Allocate buffer */
 763                 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 764                                  hroom + troom, GFP_ATOMIC);
 765                 if (!frag) {
 766                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 767                                       IPSTATS_MIB_FRAGFAILS);
 768                         err = -ENOMEM;
 769                         goto fail;
 770                 }
 771
 772                 /*
 773                  *      Set up data on packet
 774                  */
 775
 776                 ip6_copy_metadata(frag, skb);
 777                 skb_reserve(frag, hroom);
 778                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 779                 skb_reset_network_header(frag);
 780                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 781                 frag->transport_header = (frag->network_header + hlen +
 782                                           sizeof(struct frag_hdr));
 783
 784                 /*
 785                  *      Charge the memory for the fragment to any owner
 786                  *      it might possess
 787                  */
 788                 if (skb->sk)
 789                         skb_set_owner_w(frag, skb->sk);
 790
 791                 /*
 792                  *      Copy the packet header into the new buffer.
 793                  */
 794                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 795
 796                 /*
 797                  *      Build fragment header.
 798                  */
 799                 fh->nexthdr = nexthdr;
 800                 fh->reserved = 0;
 801                 fh->identification = frag_id;
 802
 803                 /*
 804                  *      Copy a block of the IP datagram.
 805                  */
 806                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 807                                      len));
 808                 left -= len;
 809
 810                 fh->frag_off = htons(offset);
 811                 if (left > 0)
 812                         fh->frag_off |= htons(IP6_MF);
 813                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 814                                                     sizeof(struct ipv6hdr));
 815
 816                 ptr += len;
 817                 offset += len;
 818
 819                 /*
 820                  *      Put this fragment into the sending queue.
 821                  */
 822                 err = output(net, sk, frag);
 823                 if (err)
 824                         goto fail;
 825
 826                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 827                               IPSTATS_MIB_FRAGCREATES);
 828         }
 829         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 830                       IPSTATS_MIB_FRAGOKS);
 831         consume_skb(skb);
 832         return err;
 833
 834 fail_toobig:
 835         if (skb->sk && dst_allfrag(skb_dst(skb)))
 836                 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 837
 838         skb->dev = skb_dst(skb)->dev;
 839         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 840         err = -EMSGSIZE;
 841
 842 fail:
 843         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 844                       IPSTATS_MIB_FRAGFAILS);
 845         kfree_skb(skb);
 846         return err;
 847 }
 848
 849 static inline int ip6_rt_check(const struct rt6key *rt_key,
 850                                const struct in6_addr *fl_addr,
 851                                const struct in6_addr *addr_cache)
 852 {
 853         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 854                 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
 855 }
 856
 857 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 858                                           struct dst_entry *dst,
 859                                           const struct flowi6 *fl6)
 860 {
 861         struct ipv6_pinfo *np = inet6_sk(sk);
 862         struct rt6_info *rt;
 863
 864         if (!dst)
 865                 goto out;
 866
 867         if (dst->ops->family != AF_INET6) {
 868                 dst_release(dst);
 869                 return NULL;
 870         }
 871
 872         rt = (struct rt6_info *)dst;
 873         /* Yes, checking route validity in not connected
 874          * case is not very simple. Take into account,
 875          * that we do not support routing by source, TOS,
 876          * and MSG_DONTROUTE            --ANK (980726)
 877          *
 878          * 1. ip6_rt_check(): If route was host route,
 879          *    check that cached destination is current.
 880          *    If it is network route, we still may
 881          *    check its validity using saved pointer
 882          *    to the last used address: daddr_cache.
 883          *    We do not want to save whole address now,
 884          *    (because main consumer of this service
 885          *    is tcp, which has not this problem),
 886          *    so that the last trick works only on connected
 887          *    sockets.
 888          * 2. oif also should be the same.
 889          */
 890         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 891 #ifdef CONFIG_IPV6_SUBTREES
 892             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 893 #endif
 894            (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
 895               (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
 896                 dst_release(dst);
 897                 dst = NULL;
 898         }
 899
 900 out:
 901         return dst;
 902 }
 903
 904 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
 905                                struct dst_entry **dst, struct flowi6 *fl6)
 906 {
 907 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 908         struct neighbour *n;
 909         struct rt6_info *rt;
 910 #endif
 911         int err;
 912
 913         /* The correct way to handle this would be to do
 914          * ip6_route_get_saddr, and then ip6_route_output; however,
 915          * the route-specific preferred source forces the
 916          * ip6_route_output call _before_ ip6_route_get_saddr.
 917          *
 918          * In source specific routing (no src=any default route),
 919          * ip6_route_output will fail given src=any saddr, though, so
 920          * that's why we try it again later.
 921          */
 922         if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
 923                 struct rt6_info *rt;
 924                 bool had_dst = *dst != NULL;
 925
 926                 if (!had_dst)
 927                         *dst = ip6_route_output(net, sk, fl6);
 928                 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
 929                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 930                                           sk ? inet6_sk(sk)->srcprefs : 0,
 931                                           &fl6->saddr);
 932                 if (err)
 933                         goto out_err_release;
 934
 935                 /* If we had an erroneous initial result, pretend it
 936                  * never existed and let the SA-enabled version take
 937                  * over.
 938                  */
 939                 if (!had_dst && (*dst)->error) {
 940                         dst_release(*dst);
 941                         *dst = NULL;
 942                 }
 943         }
 944
 945         if (!*dst)
 946                 *dst = ip6_route_output(net, sk, fl6);
 947
 948         err = (*dst)->error;
 949         if (err)
 950                 goto out_err_release;
 951
 952 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 953         /*
 954          * Here if the dst entry we've looked up
 955          * has a neighbour entry that is in the INCOMPLETE
 956          * state and the src address from the flow is
 957          * marked as OPTIMISTIC, we release the found
 958          * dst entry and replace it instead with the
 959          * dst entry of the nexthop router
 960          */
 961         rt = (struct rt6_info *) *dst;
 962         rcu_read_lock_bh();
 963         n = __ipv6_neigh_lookup_noref(rt->dst.dev,
 964                                       rt6_nexthop(rt, &fl6->daddr));
 965         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 966         rcu_read_unlock_bh();
 967
 968         if (err) {
 969                 struct inet6_ifaddr *ifp;
 970                 struct flowi6 fl_gw6;
 971                 int redirect;
 972
 973                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 974                                       (*dst)->dev, 1);
 975
 976                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 977                 if (ifp)
 978                         in6_ifa_put(ifp);
 979
 980                 if (redirect) {
 981                         /*
 982                          * We need to get the dst entry for the
 983                          * default router instead
 984                          */
 985                         dst_release(*dst);
 986                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 987                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 988                         *dst = ip6_route_output(net, sk, &fl_gw6);
 989                         err = (*dst)->error;
 990                         if (err)
 991                                 goto out_err_release;
 992                 }
 993         }
 994 #endif
 995
 996         return 0;
 997
 998 out_err_release:
 999         if (err == -ENETUNREACH)
1000                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1001         dst_release(*dst);
1002         *dst = NULL;
1003         return err;
1004 }
1005
1006 /**
1007  *      ip6_dst_lookup - perform route lookup on flow
1008  *      @sk: socket which provides route info
1009  *      @dst: pointer to dst_entry * for result
1010  *      @fl6: flow to lookup
1011  *
1012  *      This function performs a route lookup on the given flow.
1013  *
1014  *      It returns zero on success, or a standard errno code on error.
1015  */
1016 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1017                    struct flowi6 *fl6)
1018 {
1019         *dst = NULL;
1020         return ip6_dst_lookup_tail(net, sk, dst, fl6);
1021 }
1022 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1023
1024 /**
1025  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1026  *      @sk: socket which provides route info
1027  *      @fl6: flow to lookup
1028  *      @final_dst: final destination address for ipsec lookup
1029  *
1030  *      This function performs a route lookup on the given flow.
1031  *
1032  *      It returns a valid dst pointer on success, or a pointer encoded
1033  *      error code.
1034  */
1035 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1036                                       const struct in6_addr *final_dst)
1037 {
1038         struct dst_entry *dst = NULL;
1039         int err;
1040
1041         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1042         if (err)
1043                 return ERR_PTR(err);
1044         if (final_dst)
1045                 fl6->daddr = *final_dst;
1046         if (!fl6->flowi6_oif)
1047                 fl6->flowi6_oif = l3mdev_fib_oif(dst->dev);
1048
1049         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1050 }
1051 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1052
1053 /**
1054  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1055  *      @sk: socket which provides the dst cache and route info
1056  *      @fl6: flow to lookup
1057  *      @final_dst: final destination address for ipsec lookup
1058  *
1059  *      This function performs a route lookup on the given flow with the
1060  *      possibility of using the cached route in the socket if it is valid.
1061  *      It will take the socket dst lock when operating on the dst cache.
1062  *      As a result, this function can only be used in process context.
1063  *
1064  *      It returns a valid dst pointer on success, or a pointer encoded
1065  *      error code.
1066  */
1067 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1068                                          const struct in6_addr *final_dst)
1069 {
1070         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1071         int err;
1072
1073         dst = ip6_sk_dst_check(sk, dst, fl6);
1074
1075         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1076         if (err)
1077                 return ERR_PTR(err);
1078         if (final_dst)
1079                 fl6->daddr = *final_dst;
1080
1081         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1082 }
1083 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1084
1085 static inline int ip6_ufo_append_data(struct sock *sk,
1086                         struct sk_buff_head *queue,
1087                         int getfrag(void *from, char *to, int offset, int len,
1088                         int odd, struct sk_buff *skb),
1089                         void *from, int length, int hh_len, int fragheaderlen,
1090                         int transhdrlen, int mtu, unsigned int flags,
1091                         const struct flowi6 *fl6)
1092
1093 {
1094         struct sk_buff *skb;
1095         int err;
1096
1097         /* There is support for UDP large send offload by network
1098          * device, so create one single skb packet containing complete
1099          * udp datagram
1100          */
1101         skb = skb_peek_tail(queue);
1102         if (!skb) {
1103                 skb = sock_alloc_send_skb(sk,
1104                         hh_len + fragheaderlen + transhdrlen + 20,
1105                         (flags & MSG_DONTWAIT), &err);
1106                 if (!skb)
1107                         return err;
1108
1109                 /* reserve space for Hardware header */
1110                 skb_reserve(skb, hh_len);
1111
1112                 /* create space for UDP/IP header */
1113                 skb_put(skb, fragheaderlen + transhdrlen);
1114
1115                 /* initialize network header pointer */
1116                 skb_reset_network_header(skb);
1117
1118                 /* initialize protocol header pointer */
1119                 skb->transport_header = skb->network_header + fragheaderlen;
1120
1121                 skb->protocol = htons(ETH_P_IPV6);
1122                 skb->csum = 0;
1123
1124                 __skb_queue_tail(queue, skb);
1125         } else if (skb_is_gso(skb)) {
1126                 goto append;
1127         }
1128
1129         skb->ip_summed = CHECKSUM_PARTIAL;
1130         /* Specify the length of each IPv6 datagram fragment.
1131          * It has to be a multiple of 8.
1132          */
1133         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1134                                      sizeof(struct frag_hdr)) & ~7;
1135         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1136         skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk),
1137                                                          &fl6->daddr,
1138                                                          &fl6->saddr);
1139
1140 append:
1141         return skb_append_datato_frags(sk, skb, getfrag, from,
1142                                        (length - transhdrlen));
1143 }
1144
1145 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1146                                                gfp_t gfp)
1147 {
1148         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1149 }
1150
1151 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1152                                                 gfp_t gfp)
1153 {
1154         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1155 }
1156
1157 static void ip6_append_data_mtu(unsigned int *mtu,
1158                                 int *maxfraglen,
1159                                 unsigned int fragheaderlen,
1160                                 struct sk_buff *skb,
1161                                 struct rt6_info *rt,
1162                                 unsigned int orig_mtu)
1163 {
1164         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1165                 if (!skb) {
1166                         /* first fragment, reserve header_len */
1167                         *mtu = orig_mtu - rt->dst.header_len;
1168
1169                 } else {
1170                         /*
1171                          * this fragment is not first, the headers
1172                          * space is regarded as data space.
1173                          */
1174                         *mtu = orig_mtu;
1175                 }
1176                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1177                               + fragheaderlen - sizeof(struct frag_hdr);
1178         }
1179 }
1180
1181 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1182                           struct inet6_cork *v6_cork,
1183                           int hlimit, int tclass, struct ipv6_txoptions *opt,
1184                           struct rt6_info *rt, struct flowi6 *fl6)
1185 {
1186         struct ipv6_pinfo *np = inet6_sk(sk);
1187         unsigned int mtu;
1188
1189         /*
1190          * setup for corking
1191          */
1192         if (opt) {
1193                 if (WARN_ON(v6_cork->opt))
1194                         return -EINVAL;
1195
1196                 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1197                 if (unlikely(!v6_cork->opt))
1198                         return -ENOBUFS;
1199
1200                 v6_cork->opt->tot_len = opt->tot_len;
1201                 v6_cork->opt->opt_flen = opt->opt_flen;
1202                 v6_cork->opt->opt_nflen = opt->opt_nflen;
1203
1204                 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1205                                                     sk->sk_allocation);
1206                 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1207                         return -ENOBUFS;
1208
1209                 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1210                                                     sk->sk_allocation);
1211                 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1212                         return -ENOBUFS;
1213
1214                 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1215                                                    sk->sk_allocation);
1216                 if (opt->hopopt && !v6_cork->opt->hopopt)
1217                         return -ENOBUFS;
1218
1219                 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1220                                                     sk->sk_allocation);
1221                 if (opt->srcrt && !v6_cork->opt->srcrt)
1222                         return -ENOBUFS;
1223
1224                 /* need source address above miyazawa*/
1225         }
1226         dst_hold(&rt->dst);
1227         cork->base.dst = &rt->dst;
1228         cork->fl.u.ip6 = *fl6;
1229         v6_cork->hop_limit = hlimit;
1230         v6_cork->tclass = tclass;
1231         if (rt->dst.flags & DST_XFRM_TUNNEL)
1232                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1233                       rt->dst.dev->mtu : dst_mtu(&rt->dst);
1234         else
1235                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1236                       rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1237         if (np->frag_size < mtu) {
1238                 if (np->frag_size)
1239                         mtu = np->frag_size;
1240         }
1241         cork->base.fragsize = mtu;
1242         if (dst_allfrag(rt->dst.path))
1243                 cork->base.flags |= IPCORK_ALLFRAG;
1244         cork->base.length = 0;
1245
1246         return 0;
1247 }
1248
1249 static int __ip6_append_data(struct sock *sk,
1250                              struct flowi6 *fl6,
1251                              struct sk_buff_head *queue,
1252                              struct inet_cork *cork,
1253                              struct inet6_cork *v6_cork,
1254                              struct page_frag *pfrag,
1255                              int getfrag(void *from, char *to, int offset,
1256                                          int len, int odd, struct sk_buff *skb),
1257                              void *from, int length, int transhdrlen,
1258                              unsigned int flags, int dontfrag)
1259 {
1260         struct sk_buff *skb, *skb_prev = NULL;
1261         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1262         int exthdrlen = 0;
1263         int dst_exthdrlen = 0;
1264         int hh_len;
1265         int copy;
1266         int err;
1267         int offset = 0;
1268         __u8 tx_flags = 0;
1269         u32 tskey = 0;
1270         struct rt6_info *rt = (struct rt6_info *)cork->dst;
1271         struct ipv6_txoptions *opt = v6_cork->opt;
1272         int csummode = CHECKSUM_NONE;
1273         unsigned int maxnonfragsize, headersize;
1274
1275         skb = skb_peek_tail(queue);
1276         if (!skb) {
1277                 exthdrlen = opt ? opt->opt_flen : 0;
1278                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1279         }
1280
1281         mtu = cork->fragsize;
1282         orig_mtu = mtu;
1283
1284         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1285
1286         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1287                         (opt ? opt->opt_nflen : 0);
1288         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1289                      sizeof(struct frag_hdr);
1290
1291         headersize = sizeof(struct ipv6hdr) +
1292                      (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1293                      (dst_allfrag(&rt->dst) ?
1294                       sizeof(struct frag_hdr) : 0) +
1295                      rt->rt6i_nfheader_len;
1296
1297         if (cork->length + length > mtu - headersize && dontfrag &&
1298             (sk->sk_protocol == IPPROTO_UDP ||
1299              sk->sk_protocol == IPPROTO_RAW)) {
1300                 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1301                                 sizeof(struct ipv6hdr));
1302                 goto emsgsize;
1303         }
1304
1305         if (ip6_sk_ignore_df(sk))
1306                 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1307         else
1308                 maxnonfragsize = mtu;
1309
1310         if (cork->length + length > maxnonfragsize - headersize) {
1311 emsgsize:
1312                 ipv6_local_error(sk, EMSGSIZE, fl6,
1313                                  mtu - headersize +
1314                                  sizeof(struct ipv6hdr));
1315                 return -EMSGSIZE;
1316         }
1317
1318         /* CHECKSUM_PARTIAL only with no extension headers and when
1319          * we are not going to fragment
1320          */
1321         if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1322             headersize == sizeof(struct ipv6hdr) &&
1323             length < mtu - headersize &&
1324             !(flags & MSG_MORE) &&
1325             rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1326                 csummode = CHECKSUM_PARTIAL;
1327
1328         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1329                 sock_tx_timestamp(sk, &tx_flags);
1330                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1331                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1332                         tskey = sk->sk_tskey++;
1333         }
1334
1335         /*
1336          * Let's try using as much space as possible.
1337          * Use MTU if total length of the message fits into the MTU.
1338          * Otherwise, we need to reserve fragment header and
1339          * fragment alignment (= 8-15 octects, in total).
1340          *
1341          * Note that we may need to "move" the data from the tail of
1342          * of the buffer to the new fragment when we split
1343          * the message.
1344          *
1345          * FIXME: It may be fragmented into multiple chunks
1346          *        at once if non-fragmentable extension headers
1347          *        are too large.
1348          * --yoshfuji
1349          */
1350
1351         cork->length += length;
1352         if (((length > mtu) ||
1353              (skb && skb_is_gso(skb))) &&
1354             (sk->sk_protocol == IPPROTO_UDP) &&
1355             (rt->dst.dev->features & NETIF_F_UFO) &&
1356             (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) {
1357                 err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
1358                                           hh_len, fragheaderlen,
1359                                           transhdrlen, mtu, flags, fl6);
1360                 if (err)
1361                         goto error;
1362                 return 0;
1363         }
1364
1365         if (!skb)
1366                 goto alloc_new_skb;
1367
1368         while (length > 0) {
1369                 /* Check if the remaining data fits into current packet. */
1370                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1371                 if (copy < length)
1372                         copy = maxfraglen - skb->len;
1373
1374                 if (copy <= 0) {
1375                         char *data;
1376                         unsigned int datalen;
1377                         unsigned int fraglen;
1378                         unsigned int fraggap;
1379                         unsigned int alloclen;
1380 alloc_new_skb:
1381                         /* There's no room in the current skb */
1382                         if (skb)
1383                                 fraggap = skb->len - maxfraglen;
1384                         else
1385                                 fraggap = 0;
1386                         /* update mtu and maxfraglen if necessary */
1387                         if (!skb || !skb_prev)
1388                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1389                                                     fragheaderlen, skb, rt,
1390                                                     orig_mtu);
1391
1392                         skb_prev = skb;
1393
1394                         /*
1395                          * If remaining data exceeds the mtu,
1396                          * we know we need more fragment(s).
1397                          */
1398                         datalen = length + fraggap;
1399
1400                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1401                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1402                         if ((flags & MSG_MORE) &&
1403                             !(rt->dst.dev->features&NETIF_F_SG))
1404                                 alloclen = mtu;
1405                         else
1406                                 alloclen = datalen + fragheaderlen;
1407
1408                         alloclen += dst_exthdrlen;
1409
1410                         if (datalen != length + fraggap) {
1411                                 /*
1412                                  * this is not the last fragment, the trailer
1413                                  * space is regarded as data space.
1414                                  */
1415                                 datalen += rt->dst.trailer_len;
1416                         }
1417
1418                         alloclen += rt->dst.trailer_len;
1419                         fraglen = datalen + fragheaderlen;
1420
1421                         /*
1422                          * We just reserve space for fragment header.
1423                          * Note: this may be overallocation if the message
1424                          * (without MSG_MORE) fits into the MTU.
1425                          */
1426                         alloclen += sizeof(struct frag_hdr);
1427
1428                         if (transhdrlen) {
1429                                 skb = sock_alloc_send_skb(sk,
1430                                                 alloclen + hh_len,
1431                                                 (flags & MSG_DONTWAIT), &err);
1432                         } else {
1433                                 skb = NULL;
1434                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1435                                     2 * sk->sk_sndbuf)
1436                                         skb = sock_wmalloc(sk,
1437                                                            alloclen + hh_len, 1,
1438                                                            sk->sk_allocation);
1439                                 if (unlikely(!skb))
1440                                         err = -ENOBUFS;
1441                         }
1442                         if (!skb)
1443                                 goto error;
1444                         /*
1445                          *      Fill in the control structures
1446                          */
1447                         skb->protocol = htons(ETH_P_IPV6);
1448                         skb->ip_summed = csummode;
1449                         skb->csum = 0;
1450                         /* reserve for fragmentation and ipsec header */
1451                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1452                                     dst_exthdrlen);
1453
1454                         /* Only the initial fragment is time stamped */
1455                         skb_shinfo(skb)->tx_flags = tx_flags;
1456                         tx_flags = 0;
1457                         skb_shinfo(skb)->tskey = tskey;
1458                         tskey = 0;
1459
1460                         /*
1461                          *      Find where to start putting bytes
1462                          */
1463                         data = skb_put(skb, fraglen);
1464                         skb_set_network_header(skb, exthdrlen);
1465                         data += fragheaderlen;
1466                         skb->transport_header = (skb->network_header +
1467                                                  fragheaderlen);
1468                         if (fraggap) {
1469                                 skb->csum = skb_copy_and_csum_bits(
1470                                         skb_prev, maxfraglen,
1471                                         data + transhdrlen, fraggap, 0);
1472                                 skb_prev->csum = csum_sub(skb_prev->csum,
1473                                                           skb->csum);
1474                                 data += fraggap;
1475                                 pskb_trim_unique(skb_prev, maxfraglen);
1476                         }
1477                         copy = datalen - transhdrlen - fraggap;
1478
1479                         if (copy < 0) {
1480                                 err = -EINVAL;
1481                                 kfree_skb(skb);
1482                                 goto error;
1483                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1484                                 err = -EFAULT;
1485                                 kfree_skb(skb);
1486                                 goto error;
1487                         }
1488
1489                         offset += copy;
1490                         length -= datalen - fraggap;
1491                         transhdrlen = 0;
1492                         exthdrlen = 0;
1493                         dst_exthdrlen = 0;
1494
1495                         /*
1496                          * Put the packet on the pending queue
1497                          */
1498                         __skb_queue_tail(queue, skb);
1499                         continue;
1500                 }
1501
1502                 if (copy > length)
1503                         copy = length;
1504
1505                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1506                         unsigned int off;
1507
1508                         off = skb->len;
1509                         if (getfrag(from, skb_put(skb, copy),
1510                                                 offset, copy, off, skb) < 0) {
1511                                 __skb_trim(skb, off);
1512                                 err = -EFAULT;
1513                                 goto error;
1514                         }
1515                 } else {
1516                         int i = skb_shinfo(skb)->nr_frags;
1517
1518                         err = -ENOMEM;
1519                         if (!sk_page_frag_refill(sk, pfrag))
1520                                 goto error;
1521
1522                         if (!skb_can_coalesce(skb, i, pfrag->page,
1523                                               pfrag->offset)) {
1524                                 err = -EMSGSIZE;
1525                                 if (i == MAX_SKB_FRAGS)
1526                                         goto error;
1527
1528                                 __skb_fill_page_desc(skb, i, pfrag->page,
1529                                                      pfrag->offset, 0);
1530                                 skb_shinfo(skb)->nr_frags = ++i;
1531                                 get_page(pfrag->page);
1532                         }
1533                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1534                         if (getfrag(from,
1535                                     page_address(pfrag->page) + pfrag->offset,
1536                                     offset, copy, skb->len, skb) < 0)
1537                                 goto error_efault;
1538
1539                         pfrag->offset += copy;
1540                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1541                         skb->len += copy;
1542                         skb->data_len += copy;
1543                         skb->truesize += copy;
1544                         atomic_add(copy, &sk->sk_wmem_alloc);
1545                 }
1546                 offset += copy;
1547                 length -= copy;
1548         }
1549
1550         return 0;
1551
1552 error_efault:
1553         err = -EFAULT;
1554 error:
1555         cork->length -= length;
1556         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1557         return err;
1558 }
1559
1560 int ip6_append_data(struct sock *sk,
1561                     int getfrag(void *from, char *to, int offset, int len,
1562                                 int odd, struct sk_buff *skb),
1563                     void *from, int length, int transhdrlen, int hlimit,
1564                     int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1565                     struct rt6_info *rt, unsigned int flags, int dontfrag)
1566 {
1567         struct inet_sock *inet = inet_sk(sk);
1568         struct ipv6_pinfo *np = inet6_sk(sk);
1569         int exthdrlen;
1570         int err;
1571
1572         if (flags&MSG_PROBE)
1573                 return 0;
1574         if (skb_queue_empty(&sk->sk_write_queue)) {
1575                 /*
1576                  * setup for corking
1577                  */
1578                 err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit,
1579                                      tclass, opt, rt, fl6);
1580                 if (err)
1581                         return err;
1582
1583                 exthdrlen = (opt ? opt->opt_flen : 0);
1584                 length += exthdrlen;
1585                 transhdrlen += exthdrlen;
1586         } else {
1587                 fl6 = &inet->cork.fl.u.ip6;
1588                 transhdrlen = 0;
1589         }
1590
1591         return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1592                                  &np->cork, sk_page_frag(sk), getfrag,
1593                                  from, length, transhdrlen, flags, dontfrag);
1594 }
1595 EXPORT_SYMBOL_GPL(ip6_append_data);
1596
1597 static void ip6_cork_release(struct inet_cork_full *cork,
1598                              struct inet6_cork *v6_cork)
1599 {
1600         if (v6_cork->opt) {
1601                 kfree(v6_cork->opt->dst0opt);
1602                 kfree(v6_cork->opt->dst1opt);
1603                 kfree(v6_cork->opt->hopopt);
1604                 kfree(v6_cork->opt->srcrt);
1605                 kfree(v6_cork->opt);
1606                 v6_cork->opt = NULL;
1607         }
1608
1609         if (cork->base.dst) {
1610                 dst_release(cork->base.dst);
1611                 cork->base.dst = NULL;
1612                 cork->base.flags &= ~IPCORK_ALLFRAG;
1613         }
1614         memset(&cork->fl, 0, sizeof(cork->fl));
1615 }
1616
1617 struct sk_buff *__ip6_make_skb(struct sock *sk,
1618                                struct sk_buff_head *queue,
1619                                struct inet_cork_full *cork,
1620                                struct inet6_cork *v6_cork)
1621 {
1622         struct sk_buff *skb, *tmp_skb;
1623         struct sk_buff **tail_skb;
1624         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1625         struct ipv6_pinfo *np = inet6_sk(sk);
1626         struct net *net = sock_net(sk);
1627         struct ipv6hdr *hdr;
1628         struct ipv6_txoptions *opt = v6_cork->opt;
1629         struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1630         struct flowi6 *fl6 = &cork->fl.u.ip6;
1631         unsigned char proto = fl6->flowi6_proto;
1632
1633         skb = __skb_dequeue(queue);
1634         if (!skb)
1635                 goto out;
1636         tail_skb = &(skb_shinfo(skb)->frag_list);
1637
1638         /* move skb->data to ip header from ext header */
1639         if (skb->data < skb_network_header(skb))
1640                 __skb_pull(skb, skb_network_offset(skb));
1641         while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1642                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1643                 *tail_skb = tmp_skb;
1644                 tail_skb = &(tmp_skb->next);
1645                 skb->len += tmp_skb->len;
1646                 skb->data_len += tmp_skb->len;
1647                 skb->truesize += tmp_skb->truesize;
1648                 tmp_skb->destructor = NULL;
1649                 tmp_skb->sk = NULL;
1650         }
1651
1652         /* Allow local fragmentation. */
1653         skb->ignore_df = ip6_sk_ignore_df(sk);
1654
1655         *final_dst = fl6->daddr;
1656         __skb_pull(skb, skb_network_header_len(skb));
1657         if (opt && opt->opt_flen)
1658                 ipv6_push_frag_opts(skb, opt, &proto);
1659         if (opt && opt->opt_nflen)
1660                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1661
1662         skb_push(skb, sizeof(struct ipv6hdr));
1663         skb_reset_network_header(skb);
1664         hdr = ipv6_hdr(skb);
1665
1666         ip6_flow_hdr(hdr, v6_cork->tclass,
1667                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1668                                         np->autoflowlabel, fl6));
1669         hdr->hop_limit = v6_cork->hop_limit;
1670         hdr->nexthdr = proto;
1671         hdr->saddr = fl6->saddr;
1672         hdr->daddr = *final_dst;
1673
1674         skb->priority = sk->sk_priority;
1675         skb->mark = sk->sk_mark;
1676
1677         skb_dst_set(skb, dst_clone(&rt->dst));
1678         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1679         if (proto == IPPROTO_ICMPV6) {
1680                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1681
1682                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1683                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1684         }
1685
1686         ip6_cork_release(cork, v6_cork);
1687 out:
1688         return skb;
1689 }
1690
1691 int ip6_send_skb(struct sk_buff *skb)
1692 {
1693         struct net *net = sock_net(skb->sk);
1694         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1695         int err;
1696
1697         err = ip6_local_out(net, skb->sk, skb);
1698         if (err) {
1699                 if (err > 0)
1700                         err = net_xmit_errno(err);
1701                 if (err)
1702                         IP6_INC_STATS(net, rt->rt6i_idev,
1703                                       IPSTATS_MIB_OUTDISCARDS);
1704         }
1705
1706         return err;
1707 }
1708
1709 int ip6_push_pending_frames(struct sock *sk)
1710 {
1711         struct sk_buff *skb;
1712
1713         skb = ip6_finish_skb(sk);
1714         if (!skb)
1715                 return 0;
1716
1717         return ip6_send_skb(skb);
1718 }
1719 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1720
1721 static void __ip6_flush_pending_frames(struct sock *sk,
1722                                        struct sk_buff_head *queue,
1723                                        struct inet_cork_full *cork,
1724                                        struct inet6_cork *v6_cork)
1725 {
1726         struct sk_buff *skb;
1727
1728         while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1729                 if (skb_dst(skb))
1730                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1731                                       IPSTATS_MIB_OUTDISCARDS);
1732                 kfree_skb(skb);
1733         }
1734
1735         ip6_cork_release(cork, v6_cork);
1736 }
1737
1738 void ip6_flush_pending_frames(struct sock *sk)
1739 {
1740         __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1741                                    &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1742 }
1743 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1744
1745 struct sk_buff *ip6_make_skb(struct sock *sk,
1746                              int getfrag(void *from, char *to, int offset,
1747                                          int len, int odd, struct sk_buff *skb),
1748                              void *from, int length, int transhdrlen,
1749                              int hlimit, int tclass,
1750                              struct ipv6_txoptions *opt, struct flowi6 *fl6,
1751                              struct rt6_info *rt, unsigned int flags,
1752                              int dontfrag)
1753 {
1754         struct inet_cork_full cork;
1755         struct inet6_cork v6_cork;
1756         struct sk_buff_head queue;
1757         int exthdrlen = (opt ? opt->opt_flen : 0);
1758         int err;
1759
1760         if (flags & MSG_PROBE)
1761                 return NULL;
1762
1763         __skb_queue_head_init(&queue);
1764
1765         cork.base.flags = 0;
1766         cork.base.addr = 0;
1767         cork.base.opt = NULL;
1768         v6_cork.opt = NULL;
1769         err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6);
1770         if (err)
1771                 return ERR_PTR(err);
1772
1773         if (dontfrag < 0)
1774                 dontfrag = inet6_sk(sk)->dontfrag;
1775
1776         err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
1777                                 &current->task_frag, getfrag, from,
1778                                 length + exthdrlen, transhdrlen + exthdrlen,
1779                                 flags, dontfrag);
1780         if (err) {
1781                 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
1782                 return ERR_PTR(err);
1783         }
1784
1785         return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
1786 }