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 (skb_warn_if_lro(skb))
 393                 goto drop;
 394
 395         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 396                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 397                                  IPSTATS_MIB_INDISCARDS);
 398                 goto drop;
 399         }
 400
 401         skb_forward_csum(skb);
 402
 403         /*
 404          *      We DO NOT make any processing on
 405          *      RA packets, pushing them to user level AS IS
 406          *      without ane WARRANTY that application will be able
 407          *      to interpret them. The reason is that we
 408          *      cannot make anything clever here.
 409          *
 410          *      We are not end-node, so that if packet contains
 411          *      AH/ESP, we cannot make anything.
 412          *      Defragmentation also would be mistake, RA packets
 413          *      cannot be fragmented, because there is no warranty
 414          *      that different fragments will go along one path. --ANK
 415          */
 416         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 417                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 418                         return 0;
 419         }
 420
 421         /*
 422          *      check and decrement ttl
 423          */
 424         if (hdr->hop_limit <= 1) {
 425                 /* Force OUTPUT device used as source address */
 426                 skb->dev = dst->dev;
 427                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 428                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 429                                  IPSTATS_MIB_INHDRERRORS);
 430
 431                 kfree_skb(skb);
 432                 return -ETIMEDOUT;
 433         }
 434
 435         /* XXX: idev->cnf.proxy_ndp? */
 436         if (net->ipv6.devconf_all->proxy_ndp &&
 437             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 438                 int proxied = ip6_forward_proxy_check(skb);
 439                 if (proxied > 0)
 440                         return ip6_input(skb);
 441                 else if (proxied < 0) {
 442                         IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 443                                          IPSTATS_MIB_INDISCARDS);
 444                         goto drop;
 445                 }
 446         }
 447
 448         if (!xfrm6_route_forward(skb)) {
 449                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 450                                  IPSTATS_MIB_INDISCARDS);
 451                 goto drop;
 452         }
 453         dst = skb_dst(skb);
 454
 455         /* IPv6 specs say nothing about it, but it is clear that we cannot
 456            send redirects to source routed frames.
 457            We don't send redirects to frames decapsulated from IPsec.
 458          */
 459         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 460                 struct in6_addr *target = NULL;
 461                 struct inet_peer *peer;
 462                 struct rt6_info *rt;
 463
 464                 /*
 465                  *      incoming and outgoing devices are the same
 466                  *      send a redirect.
 467                  */
 468
 469                 rt = (struct rt6_info *) dst;
 470                 if (rt->rt6i_flags & RTF_GATEWAY)
 471                         target = &rt->rt6i_gateway;
 472                 else
 473                         target = &hdr->daddr;
 474
 475                 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
 476
 477                 /* Limit redirects both by destination (here)
 478                    and by source (inside ndisc_send_redirect)
 479                  */
 480                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 481                         ndisc_send_redirect(skb, target);
 482                 if (peer)
 483                         inet_putpeer(peer);
 484         } else {
 485                 int addrtype = ipv6_addr_type(&hdr->saddr);
 486
 487                 /* This check is security critical. */
 488                 if (addrtype == IPV6_ADDR_ANY ||
 489                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 490                         goto error;
 491                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 492                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 493                                     ICMPV6_NOT_NEIGHBOUR, 0);
 494                         goto error;
 495                 }
 496         }
 497
 498         mtu = ip6_dst_mtu_forward(dst);
 499         if (mtu < IPV6_MIN_MTU)
 500                 mtu = IPV6_MIN_MTU;
 501
 502         if (ip6_pkt_too_big(skb, mtu)) {
 503                 /* Again, force OUTPUT device used as source address */
 504                 skb->dev = dst->dev;
 505                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 506                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 507                                  IPSTATS_MIB_INTOOBIGERRORS);
 508                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 509                                  IPSTATS_MIB_FRAGFAILS);
 510                 kfree_skb(skb);
 511                 return -EMSGSIZE;
 512         }
 513
 514         if (skb_cow(skb, dst->dev->hard_header_len)) {
 515                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 516                                  IPSTATS_MIB_OUTDISCARDS);
 517                 goto drop;
 518         }
 519
 520         hdr = ipv6_hdr(skb);
 521
 522         /* Mangling hops number delayed to point after skb COW */
 523
 524         hdr->hop_limit--;
 525
 526         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 527         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 528         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
 529                        net, NULL, skb, skb->dev, dst->dev,
 530                        ip6_forward_finish);
 531
 532 error:
 533         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 534 drop:
 535         kfree_skb(skb);
 536         return -EINVAL;
 537 }
 538
 539 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 540 {
 541         to->pkt_type = from->pkt_type;
 542         to->priority = from->priority;
 543         to->protocol = from->protocol;
 544         skb_dst_drop(to);
 545         skb_dst_set(to, dst_clone(skb_dst(from)));
 546         to->dev = from->dev;
 547         to->mark = from->mark;
 548
 549 #ifdef CONFIG_NET_SCHED
 550         to->tc_index = from->tc_index;
 551 #endif
 552         nf_copy(to, from);
 553         skb_copy_secmark(to, from);
 554 }
 555
 556 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 557                  int (*output)(struct net *, struct sock *, struct sk_buff *))
 558 {
 559         struct sk_buff *frag;
 560         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 561         struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
 562                                 inet6_sk(skb->sk) : NULL;
 563         struct ipv6hdr *tmp_hdr;
 564         struct frag_hdr *fh;
 565         unsigned int mtu, hlen, left, len;
 566         int hroom, troom;
 567         __be32 frag_id;
 568         int ptr, offset = 0, err = 0;
 569         u8 *prevhdr, nexthdr = 0;
 570
 571         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 572         nexthdr = *prevhdr;
 573
 574         mtu = ip6_skb_dst_mtu(skb);
 575
 576         /* We must not fragment if the socket is set to force MTU discovery
 577          * or if the skb it not generated by a local socket.
 578          */
 579         if (unlikely(!skb->ignore_df && skb->len > mtu))
 580                 goto fail_toobig;
 581
 582         if (IP6CB(skb)->frag_max_size) {
 583                 if (IP6CB(skb)->frag_max_size > mtu)
 584                         goto fail_toobig;
 585
 586                 /* don't send fragments larger than what we received */
 587                 mtu = IP6CB(skb)->frag_max_size;
 588                 if (mtu < IPV6_MIN_MTU)
 589                         mtu = IPV6_MIN_MTU;
 590         }
 591
 592         if (np && np->frag_size < mtu) {
 593                 if (np->frag_size)
 594                         mtu = np->frag_size;
 595         }
 596         mtu -= hlen + sizeof(struct frag_hdr);
 597
 598         frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
 599                                     &ipv6_hdr(skb)->saddr);
 600
 601         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 602         if (skb_has_frag_list(skb)) {
 603                 int first_len = skb_pagelen(skb);
 604                 struct sk_buff *frag2;
 605
 606                 if (first_len - hlen > mtu ||
 607                     ((first_len - hlen) & 7) ||
 608                     skb_cloned(skb) ||
 609                     skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
 610                         goto slow_path;
 611
 612                 skb_walk_frags(skb, frag) {
 613                         /* Correct geometry. */
 614                         if (frag->len > mtu ||
 615                             ((frag->len & 7) && frag->next) ||
 616                             skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
 617                                 goto slow_path_clean;
 618
 619                         /* Partially cloned skb? */
 620                         if (skb_shared(frag))
 621                                 goto slow_path_clean;
 622
 623                         BUG_ON(frag->sk);
 624                         if (skb->sk) {
 625                                 frag->sk = skb->sk;
 626                                 frag->destructor = sock_wfree;
 627                         }
 628                         skb->truesize -= frag->truesize;
 629                 }
 630
 631                 err = 0;
 632                 offset = 0;
 633                 /* BUILD HEADER */
 634
 635                 *prevhdr = NEXTHDR_FRAGMENT;
 636                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 637                 if (!tmp_hdr) {
 638                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 639                                       IPSTATS_MIB_FRAGFAILS);
 640                         err = -ENOMEM;
 641                         goto fail;
 642                 }
 643                 frag = skb_shinfo(skb)->frag_list;
 644                 skb_frag_list_init(skb);
 645
 646                 __skb_pull(skb, hlen);
 647                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 648                 __skb_push(skb, hlen);
 649                 skb_reset_network_header(skb);
 650                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 651
 652                 fh->nexthdr = nexthdr;
 653                 fh->reserved = 0;
 654                 fh->frag_off = htons(IP6_MF);
 655                 fh->identification = frag_id;
 656
 657                 first_len = skb_pagelen(skb);
 658                 skb->data_len = first_len - skb_headlen(skb);
 659                 skb->len = first_len;
 660                 ipv6_hdr(skb)->payload_len = htons(first_len -
 661                                                    sizeof(struct ipv6hdr));
 662
 663                 dst_hold(&rt->dst);
 664
 665                 for (;;) {
 666                         /* Prepare header of the next frame,
 667                          * before previous one went down. */
 668                         if (frag) {
 669                                 frag->ip_summed = CHECKSUM_NONE;
 670                                 skb_reset_transport_header(frag);
 671                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 672                                 __skb_push(frag, hlen);
 673                                 skb_reset_network_header(frag);
 674                                 memcpy(skb_network_header(frag), tmp_hdr,
 675                                        hlen);
 676                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 677                                 fh->nexthdr = nexthdr;
 678                                 fh->reserved = 0;
 679                                 fh->frag_off = htons(offset);
 680                                 if (frag->next)
 681                                         fh->frag_off |= htons(IP6_MF);
 682                                 fh->identification = frag_id;
 683                                 ipv6_hdr(frag)->payload_len =
 684                                                 htons(frag->len -
 685                                                       sizeof(struct ipv6hdr));
 686                                 ip6_copy_metadata(frag, skb);
 687                         }
 688
 689                         err = output(net, sk, skb);
 690                         if (!err)
 691                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 692                                               IPSTATS_MIB_FRAGCREATES);
 693
 694                         if (err || !frag)
 695                                 break;
 696
 697                         skb = frag;
 698                         frag = skb->next;
 699                         skb->next = NULL;
 700                 }
 701
 702                 kfree(tmp_hdr);
 703
 704                 if (err == 0) {
 705                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 706                                       IPSTATS_MIB_FRAGOKS);
 707                         ip6_rt_put(rt);
 708                         return 0;
 709                 }
 710
 711                 kfree_skb_list(frag);
 712
 713                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 714                               IPSTATS_MIB_FRAGFAILS);
 715                 ip6_rt_put(rt);
 716                 return err;
 717
 718 slow_path_clean:
 719                 skb_walk_frags(skb, frag2) {
 720                         if (frag2 == frag)
 721                                 break;
 722                         frag2->sk = NULL;
 723                         frag2->destructor = NULL;
 724                         skb->truesize += frag2->truesize;
 725                 }
 726         }
 727
 728 slow_path:
 729         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 730             skb_checksum_help(skb))
 731                 goto fail;
 732
 733         left = skb->len - hlen;         /* Space per frame */
 734         ptr = hlen;                     /* Where to start from */
 735
 736         /*
 737          *      Fragment the datagram.
 738          */
 739
 740         *prevhdr = NEXTHDR_FRAGMENT;
 741         troom = rt->dst.dev->needed_tailroom;
 742
 743         /*
 744          *      Keep copying data until we run out.
 745          */
 746         while (left > 0)        {
 747                 len = left;
 748                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 749                 if (len > mtu)
 750                         len = mtu;
 751                 /* IF: we are not sending up to and including the packet end
 752                    then align the next start on an eight byte boundary */
 753                 if (len < left) {
 754                         len &= ~7;
 755                 }
 756
 757                 /* Allocate buffer */
 758                 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 759                                  hroom + troom, GFP_ATOMIC);
 760                 if (!frag) {
 761                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 762                                       IPSTATS_MIB_FRAGFAILS);
 763                         err = -ENOMEM;
 764                         goto fail;
 765                 }
 766
 767                 /*
 768                  *      Set up data on packet
 769                  */
 770
 771                 ip6_copy_metadata(frag, skb);
 772                 skb_reserve(frag, hroom);
 773                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 774                 skb_reset_network_header(frag);
 775                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 776                 frag->transport_header = (frag->network_header + hlen +
 777                                           sizeof(struct frag_hdr));
 778
 779                 /*
 780                  *      Charge the memory for the fragment to any owner
 781                  *      it might possess
 782                  */
 783                 if (skb->sk)
 784                         skb_set_owner_w(frag, skb->sk);
 785
 786                 /*
 787                  *      Copy the packet header into the new buffer.
 788                  */
 789                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 790
 791                 /*
 792                  *      Build fragment header.
 793                  */
 794                 fh->nexthdr = nexthdr;
 795                 fh->reserved = 0;
 796                 fh->identification = frag_id;
 797
 798                 /*
 799                  *      Copy a block of the IP datagram.
 800                  */
 801                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 802                                      len));
 803                 left -= len;
 804
 805                 fh->frag_off = htons(offset);
 806                 if (left > 0)
 807                         fh->frag_off |= htons(IP6_MF);
 808                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 809                                                     sizeof(struct ipv6hdr));
 810
 811                 ptr += len;
 812                 offset += len;
 813
 814                 /*
 815                  *      Put this fragment into the sending queue.
 816                  */
 817                 err = output(net, sk, frag);
 818                 if (err)
 819                         goto fail;
 820
 821                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 822                               IPSTATS_MIB_FRAGCREATES);
 823         }
 824         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 825                       IPSTATS_MIB_FRAGOKS);
 826         consume_skb(skb);
 827         return err;
 828
 829 fail_toobig:
 830         if (skb->sk && dst_allfrag(skb_dst(skb)))
 831                 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 832
 833         skb->dev = skb_dst(skb)->dev;
 834         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 835         err = -EMSGSIZE;
 836
 837 fail:
 838         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 839                       IPSTATS_MIB_FRAGFAILS);
 840         kfree_skb(skb);
 841         return err;
 842 }
 843
 844 static inline int ip6_rt_check(const struct rt6key *rt_key,
 845                                const struct in6_addr *fl_addr,
 846                                const struct in6_addr *addr_cache)
 847 {
 848         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 849                 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
 850 }
 851
 852 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 853                                           struct dst_entry *dst,
 854                                           const struct flowi6 *fl6)
 855 {
 856         struct ipv6_pinfo *np = inet6_sk(sk);
 857         struct rt6_info *rt;
 858
 859         if (!dst)
 860                 goto out;
 861
 862         if (dst->ops->family != AF_INET6) {
 863                 dst_release(dst);
 864                 return NULL;
 865         }
 866
 867         rt = (struct rt6_info *)dst;
 868         /* Yes, checking route validity in not connected
 869          * case is not very simple. Take into account,
 870          * that we do not support routing by source, TOS,
 871          * and MSG_DONTROUTE            --ANK (980726)
 872          *
 873          * 1. ip6_rt_check(): If route was host route,
 874          *    check that cached destination is current.
 875          *    If it is network route, we still may
 876          *    check its validity using saved pointer
 877          *    to the last used address: daddr_cache.
 878          *    We do not want to save whole address now,
 879          *    (because main consumer of this service
 880          *    is tcp, which has not this problem),
 881          *    so that the last trick works only on connected
 882          *    sockets.
 883          * 2. oif also should be the same.
 884          */
 885         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 886 #ifdef CONFIG_IPV6_SUBTREES
 887             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 888 #endif
 889            (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
 890               (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
 891                 dst_release(dst);
 892                 dst = NULL;
 893         }
 894
 895 out:
 896         return dst;
 897 }
 898
 899 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
 900                                struct dst_entry **dst, struct flowi6 *fl6)
 901 {
 902 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 903         struct neighbour *n;
 904         struct rt6_info *rt;
 905 #endif
 906         int err;
 907
 908         /* The correct way to handle this would be to do
 909          * ip6_route_get_saddr, and then ip6_route_output; however,
 910          * the route-specific preferred source forces the
 911          * ip6_route_output call _before_ ip6_route_get_saddr.
 912          *
 913          * In source specific routing (no src=any default route),
 914          * ip6_route_output will fail given src=any saddr, though, so
 915          * that's why we try it again later.
 916          */
 917         if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
 918                 struct rt6_info *rt;
 919                 bool had_dst = *dst != NULL;
 920
 921                 if (!had_dst)
 922                         *dst = ip6_route_output(net, sk, fl6);
 923                 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
 924                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 925                                           sk ? inet6_sk(sk)->srcprefs : 0,
 926                                           &fl6->saddr);
 927                 if (err)
 928                         goto out_err_release;
 929
 930                 /* If we had an erroneous initial result, pretend it
 931                  * never existed and let the SA-enabled version take
 932                  * over.
 933                  */
 934                 if (!had_dst && (*dst)->error) {
 935                         dst_release(*dst);
 936                         *dst = NULL;
 937                 }
 938         }
 939
 940         if (!*dst)
 941                 *dst = ip6_route_output(net, sk, fl6);
 942
 943         err = (*dst)->error;
 944         if (err)
 945                 goto out_err_release;
 946
 947 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 948         /*
 949          * Here if the dst entry we've looked up
 950          * has a neighbour entry that is in the INCOMPLETE
 951          * state and the src address from the flow is
 952          * marked as OPTIMISTIC, we release the found
 953          * dst entry and replace it instead with the
 954          * dst entry of the nexthop router
 955          */
 956         rt = (struct rt6_info *) *dst;
 957         rcu_read_lock_bh();
 958         n = __ipv6_neigh_lookup_noref(rt->dst.dev,
 959                                       rt6_nexthop(rt, &fl6->daddr));
 960         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 961         rcu_read_unlock_bh();
 962
 963         if (err) {
 964                 struct inet6_ifaddr *ifp;
 965                 struct flowi6 fl_gw6;
 966                 int redirect;
 967
 968                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 969                                       (*dst)->dev, 1);
 970
 971                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 972                 if (ifp)
 973                         in6_ifa_put(ifp);
 974
 975                 if (redirect) {
 976                         /*
 977                          * We need to get the dst entry for the
 978                          * default router instead
 979                          */
 980                         dst_release(*dst);
 981                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 982                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 983                         *dst = ip6_route_output(net, sk, &fl_gw6);
 984                         err = (*dst)->error;
 985                         if (err)
 986                                 goto out_err_release;
 987                 }
 988         }
 989 #endif
 990
 991         return 0;
 992
 993 out_err_release:
 994         if (err == -ENETUNREACH)
 995                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 996         dst_release(*dst);
 997         *dst = NULL;
 998         return err;
 999 }
1000
1001 /**
1002  *      ip6_dst_lookup - perform route lookup on flow
1003  *      @sk: socket which provides route info
1004  *      @dst: pointer to dst_entry * for result
1005  *      @fl6: flow to lookup
1006  *
1007  *      This function performs a route lookup on the given flow.
1008  *
1009  *      It returns zero on success, or a standard errno code on error.
1010  */
1011 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1012                    struct flowi6 *fl6)
1013 {
1014         *dst = NULL;
1015         return ip6_dst_lookup_tail(net, sk, dst, fl6);
1016 }
1017 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1018
1019 /**
1020  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1021  *      @sk: socket which provides route info
1022  *      @fl6: flow to lookup
1023  *      @final_dst: final destination address for ipsec lookup
1024  *
1025  *      This function performs a route lookup on the given flow.
1026  *
1027  *      It returns a valid dst pointer on success, or a pointer encoded
1028  *      error code.
1029  */
1030 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1031                                       const struct in6_addr *final_dst)
1032 {
1033         struct dst_entry *dst = NULL;
1034         int err;
1035
1036         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1037         if (err)
1038                 return ERR_PTR(err);
1039         if (final_dst)
1040                 fl6->daddr = *final_dst;
1041         if (!fl6->flowi6_oif)
1042                 fl6->flowi6_oif = l3mdev_fib_oif(dst->dev);
1043
1044         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1045 }
1046 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1047
1048 /**
1049  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1050  *      @sk: socket which provides the dst cache and route info
1051  *      @fl6: flow to lookup
1052  *      @final_dst: final destination address for ipsec lookup
1053  *
1054  *      This function performs a route lookup on the given flow with the
1055  *      possibility of using the cached route in the socket if it is valid.
1056  *      It will take the socket dst lock when operating on the dst cache.
1057  *      As a result, this function can only be used in process context.
1058  *
1059  *      It returns a valid dst pointer on success, or a pointer encoded
1060  *      error code.
1061  */
1062 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1063                                          const struct in6_addr *final_dst)
1064 {
1065         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1066         int err;
1067
1068         dst = ip6_sk_dst_check(sk, dst, fl6);
1069
1070         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1071         if (err)
1072                 return ERR_PTR(err);
1073         if (final_dst)
1074                 fl6->daddr = *final_dst;
1075
1076         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1077 }
1078 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1079
1080 static inline int ip6_ufo_append_data(struct sock *sk,
1081                         struct sk_buff_head *queue,
1082                         int getfrag(void *from, char *to, int offset, int len,
1083                         int odd, struct sk_buff *skb),
1084                         void *from, int length, int hh_len, int fragheaderlen,
1085                         int transhdrlen, int mtu, unsigned int flags,
1086                         const struct flowi6 *fl6)
1087
1088 {
1089         struct sk_buff *skb;
1090         int err;
1091
1092         /* There is support for UDP large send offload by network
1093          * device, so create one single skb packet containing complete
1094          * udp datagram
1095          */
1096         skb = skb_peek_tail(queue);
1097         if (!skb) {
1098                 skb = sock_alloc_send_skb(sk,
1099                         hh_len + fragheaderlen + transhdrlen + 20,
1100                         (flags & MSG_DONTWAIT), &err);
1101                 if (!skb)
1102                         return err;
1103
1104                 /* reserve space for Hardware header */
1105                 skb_reserve(skb, hh_len);
1106
1107                 /* create space for UDP/IP header */
1108                 skb_put(skb, fragheaderlen + transhdrlen);
1109
1110                 /* initialize network header pointer */
1111                 skb_reset_network_header(skb);
1112
1113                 /* initialize protocol header pointer */
1114                 skb->transport_header = skb->network_header + fragheaderlen;
1115
1116                 skb->protocol = htons(ETH_P_IPV6);
1117                 skb->csum = 0;
1118
1119                 __skb_queue_tail(queue, skb);
1120         } else if (skb_is_gso(skb)) {
1121                 goto append;
1122         }
1123
1124         skb->ip_summed = CHECKSUM_PARTIAL;
1125         /* Specify the length of each IPv6 datagram fragment.
1126          * It has to be a multiple of 8.
1127          */
1128         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1129                                      sizeof(struct frag_hdr)) & ~7;
1130         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1131         skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk),
1132                                                          &fl6->daddr,
1133                                                          &fl6->saddr);
1134
1135 append:
1136         return skb_append_datato_frags(sk, skb, getfrag, from,
1137                                        (length - transhdrlen));
1138 }
1139
1140 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1141                                                gfp_t gfp)
1142 {
1143         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1144 }
1145
1146 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1147                                                 gfp_t gfp)
1148 {
1149         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1150 }
1151
1152 static void ip6_append_data_mtu(unsigned int *mtu,
1153                                 int *maxfraglen,
1154                                 unsigned int fragheaderlen,
1155                                 struct sk_buff *skb,
1156                                 struct rt6_info *rt,
1157                                 unsigned int orig_mtu)
1158 {
1159         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1160                 if (!skb) {
1161                         /* first fragment, reserve header_len */
1162                         *mtu = orig_mtu - rt->dst.header_len;
1163
1164                 } else {
1165                         /*
1166                          * this fragment is not first, the headers
1167                          * space is regarded as data space.
1168                          */
1169                         *mtu = orig_mtu;
1170                 }
1171                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1172                               + fragheaderlen - sizeof(struct frag_hdr);
1173         }
1174 }
1175
1176 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1177                           struct inet6_cork *v6_cork,
1178                           int hlimit, int tclass, struct ipv6_txoptions *opt,
1179                           struct rt6_info *rt, struct flowi6 *fl6)
1180 {
1181         struct ipv6_pinfo *np = inet6_sk(sk);
1182         unsigned int mtu;
1183
1184         /*
1185          * setup for corking
1186          */
1187         if (opt) {
1188                 if (WARN_ON(v6_cork->opt))
1189                         return -EINVAL;
1190
1191                 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1192                 if (unlikely(!v6_cork->opt))
1193                         return -ENOBUFS;
1194
1195                 v6_cork->opt->tot_len = opt->tot_len;
1196                 v6_cork->opt->opt_flen = opt->opt_flen;
1197                 v6_cork->opt->opt_nflen = opt->opt_nflen;
1198
1199                 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1200                                                     sk->sk_allocation);
1201                 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1202                         return -ENOBUFS;
1203
1204                 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1205                                                     sk->sk_allocation);
1206                 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1207                         return -ENOBUFS;
1208
1209                 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1210                                                    sk->sk_allocation);
1211                 if (opt->hopopt && !v6_cork->opt->hopopt)
1212                         return -ENOBUFS;
1213
1214                 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1215                                                     sk->sk_allocation);
1216                 if (opt->srcrt && !v6_cork->opt->srcrt)
1217                         return -ENOBUFS;
1218
1219                 /* need source address above miyazawa*/
1220         }
1221         dst_hold(&rt->dst);
1222         cork->base.dst = &rt->dst;
1223         cork->fl.u.ip6 = *fl6;
1224         v6_cork->hop_limit = hlimit;
1225         v6_cork->tclass = tclass;
1226         if (rt->dst.flags & DST_XFRM_TUNNEL)
1227                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1228                       rt->dst.dev->mtu : dst_mtu(&rt->dst);
1229         else
1230                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1231                       rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1232         if (np->frag_size < mtu) {
1233                 if (np->frag_size)
1234                         mtu = np->frag_size;
1235         }
1236         cork->base.fragsize = mtu;
1237         if (dst_allfrag(rt->dst.path))
1238                 cork->base.flags |= IPCORK_ALLFRAG;
1239         cork->base.length = 0;
1240
1241         return 0;
1242 }
1243
1244 static int __ip6_append_data(struct sock *sk,
1245                              struct flowi6 *fl6,
1246                              struct sk_buff_head *queue,
1247                              struct inet_cork *cork,
1248                              struct inet6_cork *v6_cork,
1249                              struct page_frag *pfrag,
1250                              int getfrag(void *from, char *to, int offset,
1251                                          int len, int odd, struct sk_buff *skb),
1252                              void *from, int length, int transhdrlen,
1253                              unsigned int flags, int dontfrag)
1254 {
1255         struct sk_buff *skb, *skb_prev = NULL;
1256         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1257         int exthdrlen = 0;
1258         int dst_exthdrlen = 0;
1259         int hh_len;
1260         int copy;
1261         int err;
1262         int offset = 0;
1263         __u8 tx_flags = 0;
1264         u32 tskey = 0;
1265         struct rt6_info *rt = (struct rt6_info *)cork->dst;
1266         struct ipv6_txoptions *opt = v6_cork->opt;
1267         int csummode = CHECKSUM_NONE;
1268
1269         skb = skb_peek_tail(queue);
1270         if (!skb) {
1271                 exthdrlen = opt ? opt->opt_flen : 0;
1272                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1273         }
1274
1275         mtu = cork->fragsize;
1276         orig_mtu = mtu;
1277
1278         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1279
1280         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1281                         (opt ? opt->opt_nflen : 0);
1282         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1283                      sizeof(struct frag_hdr);
1284
1285         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1286                 unsigned int maxnonfragsize, headersize;
1287
1288                 headersize = sizeof(struct ipv6hdr) +
1289                              (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1290                              (dst_allfrag(&rt->dst) ?
1291                               sizeof(struct frag_hdr) : 0) +
1292                              rt->rt6i_nfheader_len;
1293
1294                 if (ip6_sk_ignore_df(sk))
1295                         maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1296                 else
1297                         maxnonfragsize = mtu;
1298
1299                 /* dontfrag active */
1300                 if ((cork->length + length > mtu - headersize) && dontfrag &&
1301                     (sk->sk_protocol == IPPROTO_UDP ||
1302                      sk->sk_protocol == IPPROTO_RAW)) {
1303                         ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1304                                                    sizeof(struct ipv6hdr));
1305                         goto emsgsize;
1306                 }
1307
1308                 if (cork->length + length > maxnonfragsize - headersize) {
1309 emsgsize:
1310                         ipv6_local_error(sk, EMSGSIZE, fl6,
1311                                          mtu - headersize +
1312                                          sizeof(struct ipv6hdr));
1313                         return -EMSGSIZE;
1314                 }
1315         }
1316
1317         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1318                 sock_tx_timestamp(sk, &tx_flags);
1319                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1320                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1321                         tskey = sk->sk_tskey++;
1322         }
1323
1324         /* If this is the first and only packet and device
1325          * supports checksum offloading, let's use it.
1326          * Use transhdrlen, same as IPv4, because partial
1327          * sums only work when transhdrlen is set.
1328          */
1329         if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1330             length + fragheaderlen < mtu &&
1331             rt->dst.dev->features & NETIF_F_V6_CSUM &&
1332             !exthdrlen)
1333                 csummode = CHECKSUM_PARTIAL;
1334         /*
1335          * Let's try using as much space as possible.
1336          * Use MTU if total length of the message fits into the MTU.
1337          * Otherwise, we need to reserve fragment header and
1338          * fragment alignment (= 8-15 octects, in total).
1339          *
1340          * Note that we may need to "move" the data from the tail of
1341          * of the buffer to the new fragment when we split
1342          * the message.
1343          *
1344          * FIXME: It may be fragmented into multiple chunks
1345          *        at once if non-fragmentable extension headers
1346          *        are too large.
1347          * --yoshfuji
1348          */
1349
1350         cork->length += length;
1351         if (((length > mtu) ||
1352              (skb && skb_is_gso(skb))) &&
1353             (sk->sk_protocol == IPPROTO_UDP) &&
1354             (rt->dst.dev->features & NETIF_F_UFO) &&
1355             (sk->sk_type == SOCK_DGRAM)) {
1356                 err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
1357                                           hh_len, fragheaderlen,
1358                                           transhdrlen, mtu, flags, fl6);
1359                 if (err)
1360                         goto error;
1361                 return 0;
1362         }
1363
1364         if (!skb)
1365                 goto alloc_new_skb;
1366
1367         while (length > 0) {
1368                 /* Check if the remaining data fits into current packet. */
1369                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1370                 if (copy < length)
1371                         copy = maxfraglen - skb->len;
1372
1373                 if (copy <= 0) {
1374                         char *data;
1375                         unsigned int datalen;
1376                         unsigned int fraglen;
1377                         unsigned int fraggap;
1378                         unsigned int alloclen;
1379 alloc_new_skb:
1380                         /* There's no room in the current skb */
1381                         if (skb)
1382                                 fraggap = skb->len - maxfraglen;
1383                         else
1384                                 fraggap = 0;
1385                         /* update mtu and maxfraglen if necessary */
1386                         if (!skb || !skb_prev)
1387                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1388                                                     fragheaderlen, skb, rt,
1389                                                     orig_mtu);
1390
1391                         skb_prev = skb;
1392
1393                         /*
1394                          * If remaining data exceeds the mtu,
1395                          * we know we need more fragment(s).
1396                          */
1397                         datalen = length + fraggap;
1398
1399                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1400                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1401                         if ((flags & MSG_MORE) &&
1402                             !(rt->dst.dev->features&NETIF_F_SG))
1403                                 alloclen = mtu;
1404                         else
1405                                 alloclen = datalen + fragheaderlen;
1406
1407                         alloclen += dst_exthdrlen;
1408
1409                         if (datalen != length + fraggap) {
1410                                 /*
1411                                  * this is not the last fragment, the trailer
1412                                  * space is regarded as data space.
1413                                  */
1414                                 datalen += rt->dst.trailer_len;
1415                         }
1416
1417                         alloclen += rt->dst.trailer_len;
1418                         fraglen = datalen + fragheaderlen;
1419
1420                         /*
1421                          * We just reserve space for fragment header.
1422                          * Note: this may be overallocation if the message
1423                          * (without MSG_MORE) fits into the MTU.
1424                          */
1425                         alloclen += sizeof(struct frag_hdr);
1426
1427                         if (transhdrlen) {
1428                                 skb = sock_alloc_send_skb(sk,
1429                                                 alloclen + hh_len,
1430                                                 (flags & MSG_DONTWAIT), &err);
1431                         } else {
1432                                 skb = NULL;
1433                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1434                                     2 * sk->sk_sndbuf)
1435                                         skb = sock_wmalloc(sk,
1436                                                            alloclen + hh_len, 1,
1437                                                            sk->sk_allocation);
1438                                 if (unlikely(!skb))
1439                                         err = -ENOBUFS;
1440                         }
1441                         if (!skb)
1442                                 goto error;
1443                         /*
1444                          *      Fill in the control structures
1445                          */
1446                         skb->protocol = htons(ETH_P_IPV6);
1447                         skb->ip_summed = csummode;
1448                         skb->csum = 0;
1449                         /* reserve for fragmentation and ipsec header */
1450                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1451                                     dst_exthdrlen);
1452
1453                         /* Only the initial fragment is time stamped */
1454                         skb_shinfo(skb)->tx_flags = tx_flags;
1455                         tx_flags = 0;
1456                         skb_shinfo(skb)->tskey = tskey;
1457                         tskey = 0;
1458
1459                         /*
1460                          *      Find where to start putting bytes
1461                          */
1462                         data = skb_put(skb, fraglen);
1463                         skb_set_network_header(skb, exthdrlen);
1464                         data += fragheaderlen;
1465                         skb->transport_header = (skb->network_header +
1466                                                  fragheaderlen);
1467                         if (fraggap) {
1468                                 skb->csum = skb_copy_and_csum_bits(
1469                                         skb_prev, maxfraglen,
1470                                         data + transhdrlen, fraggap, 0);
1471                                 skb_prev->csum = csum_sub(skb_prev->csum,
1472                                                           skb->csum);
1473                                 data += fraggap;
1474                                 pskb_trim_unique(skb_prev, maxfraglen);
1475                         }
1476                         copy = datalen - transhdrlen - fraggap;
1477
1478                         if (copy < 0) {
1479                                 err = -EINVAL;
1480                                 kfree_skb(skb);
1481                                 goto error;
1482                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1483                                 err = -EFAULT;
1484                                 kfree_skb(skb);
1485                                 goto error;
1486                         }
1487
1488                         offset += copy;
1489                         length -= datalen - fraggap;
1490                         transhdrlen = 0;
1491                         exthdrlen = 0;
1492                         dst_exthdrlen = 0;
1493
1494                         /*
1495                          * Put the packet on the pending queue
1496                          */
1497                         __skb_queue_tail(queue, skb);
1498                         continue;
1499                 }
1500
1501                 if (copy > length)
1502                         copy = length;
1503
1504                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1505                         unsigned int off;
1506
1507                         off = skb->len;
1508                         if (getfrag(from, skb_put(skb, copy),
1509                                                 offset, copy, off, skb) < 0) {
1510                                 __skb_trim(skb, off);
1511                                 err = -EFAULT;
1512                                 goto error;
1513                         }
1514                 } else {
1515                         int i = skb_shinfo(skb)->nr_frags;
1516
1517                         err = -ENOMEM;
1518                         if (!sk_page_frag_refill(sk, pfrag))
1519                                 goto error;
1520
1521                         if (!skb_can_coalesce(skb, i, pfrag->page,
1522                                               pfrag->offset)) {
1523                                 err = -EMSGSIZE;
1524                                 if (i == MAX_SKB_FRAGS)
1525                                         goto error;
1526
1527                                 __skb_fill_page_desc(skb, i, pfrag->page,
1528                                                      pfrag->offset, 0);
1529                                 skb_shinfo(skb)->nr_frags = ++i;
1530                                 get_page(pfrag->page);
1531                         }
1532                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1533                         if (getfrag(from,
1534                                     page_address(pfrag->page) + pfrag->offset,
1535                                     offset, copy, skb->len, skb) < 0)
1536                                 goto error_efault;
1537
1538                         pfrag->offset += copy;
1539                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1540                         skb->len += copy;
1541                         skb->data_len += copy;
1542                         skb->truesize += copy;
1543                         atomic_add(copy, &sk->sk_wmem_alloc);
1544                 }
1545                 offset += copy;
1546                 length -= copy;
1547         }
1548
1549         return 0;
1550
1551 error_efault:
1552         err = -EFAULT;
1553 error:
1554         cork->length -= length;
1555         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1556         return err;
1557 }
1558
1559 int ip6_append_data(struct sock *sk,
1560                     int getfrag(void *from, char *to, int offset, int len,
1561                                 int odd, struct sk_buff *skb),
1562                     void *from, int length, int transhdrlen, int hlimit,
1563                     int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1564                     struct rt6_info *rt, unsigned int flags, int dontfrag)
1565 {
1566         struct inet_sock *inet = inet_sk(sk);
1567         struct ipv6_pinfo *np = inet6_sk(sk);
1568         int exthdrlen;
1569         int err;
1570
1571         if (flags&MSG_PROBE)
1572                 return 0;
1573         if (skb_queue_empty(&sk->sk_write_queue)) {
1574                 /*
1575                  * setup for corking
1576                  */
1577                 err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit,
1578                                      tclass, opt, rt, fl6);
1579                 if (err)
1580                         return err;
1581
1582                 exthdrlen = (opt ? opt->opt_flen : 0);
1583                 length += exthdrlen;
1584                 transhdrlen += exthdrlen;
1585         } else {
1586                 fl6 = &inet->cork.fl.u.ip6;
1587                 transhdrlen = 0;
1588         }
1589
1590         return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1591                                  &np->cork, sk_page_frag(sk), getfrag,
1592                                  from, length, transhdrlen, flags, dontfrag);
1593 }
1594 EXPORT_SYMBOL_GPL(ip6_append_data);
1595
1596 static void ip6_cork_release(struct inet_cork_full *cork,
1597                              struct inet6_cork *v6_cork)
1598 {
1599         if (v6_cork->opt) {
1600                 kfree(v6_cork->opt->dst0opt);
1601                 kfree(v6_cork->opt->dst1opt);
1602                 kfree(v6_cork->opt->hopopt);
1603                 kfree(v6_cork->opt->srcrt);
1604                 kfree(v6_cork->opt);
1605                 v6_cork->opt = NULL;
1606         }
1607
1608         if (cork->base.dst) {
1609                 dst_release(cork->base.dst);
1610                 cork->base.dst = NULL;
1611                 cork->base.flags &= ~IPCORK_ALLFRAG;
1612         }
1613         memset(&cork->fl, 0, sizeof(cork->fl));
1614 }
1615
1616 struct sk_buff *__ip6_make_skb(struct sock *sk,
1617                                struct sk_buff_head *queue,
1618                                struct inet_cork_full *cork,
1619                                struct inet6_cork *v6_cork)
1620 {
1621         struct sk_buff *skb, *tmp_skb;
1622         struct sk_buff **tail_skb;
1623         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1624         struct ipv6_pinfo *np = inet6_sk(sk);
1625         struct net *net = sock_net(sk);
1626         struct ipv6hdr *hdr;
1627         struct ipv6_txoptions *opt = v6_cork->opt;
1628         struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1629         struct flowi6 *fl6 = &cork->fl.u.ip6;
1630         unsigned char proto = fl6->flowi6_proto;
1631
1632         skb = __skb_dequeue(queue);
1633         if (!skb)
1634                 goto out;
1635         tail_skb = &(skb_shinfo(skb)->frag_list);
1636
1637         /* move skb->data to ip header from ext header */
1638         if (skb->data < skb_network_header(skb))
1639                 __skb_pull(skb, skb_network_offset(skb));
1640         while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1641                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1642                 *tail_skb = tmp_skb;
1643                 tail_skb = &(tmp_skb->next);
1644                 skb->len += tmp_skb->len;
1645                 skb->data_len += tmp_skb->len;
1646                 skb->truesize += tmp_skb->truesize;
1647                 tmp_skb->destructor = NULL;
1648                 tmp_skb->sk = NULL;
1649         }
1650
1651         /* Allow local fragmentation. */
1652         skb->ignore_df = ip6_sk_ignore_df(sk);
1653
1654         *final_dst = fl6->daddr;
1655         __skb_pull(skb, skb_network_header_len(skb));
1656         if (opt && opt->opt_flen)
1657                 ipv6_push_frag_opts(skb, opt, &proto);
1658         if (opt && opt->opt_nflen)
1659                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1660
1661         skb_push(skb, sizeof(struct ipv6hdr));
1662         skb_reset_network_header(skb);
1663         hdr = ipv6_hdr(skb);
1664
1665         ip6_flow_hdr(hdr, v6_cork->tclass,
1666                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1667                                         np->autoflowlabel, fl6));
1668         hdr->hop_limit = v6_cork->hop_limit;
1669         hdr->nexthdr = proto;
1670         hdr->saddr = fl6->saddr;
1671         hdr->daddr = *final_dst;
1672
1673         skb->priority = sk->sk_priority;
1674         skb->mark = sk->sk_mark;
1675
1676         skb_dst_set(skb, dst_clone(&rt->dst));
1677         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1678         if (proto == IPPROTO_ICMPV6) {
1679                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1680
1681                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1682                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1683         }
1684
1685         ip6_cork_release(cork, v6_cork);
1686 out:
1687         return skb;
1688 }
1689
1690 int ip6_send_skb(struct sk_buff *skb)
1691 {
1692         struct net *net = sock_net(skb->sk);
1693         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1694         int err;
1695
1696         err = ip6_local_out(net, skb->sk, skb);
1697         if (err) {
1698                 if (err > 0)
1699                         err = net_xmit_errno(err);
1700                 if (err)
1701                         IP6_INC_STATS(net, rt->rt6i_idev,
1702                                       IPSTATS_MIB_OUTDISCARDS);
1703         }
1704
1705         return err;
1706 }
1707
1708 int ip6_push_pending_frames(struct sock *sk)
1709 {
1710         struct sk_buff *skb;
1711
1712         skb = ip6_finish_skb(sk);
1713         if (!skb)
1714                 return 0;
1715
1716         return ip6_send_skb(skb);
1717 }
1718 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1719
1720 static void __ip6_flush_pending_frames(struct sock *sk,
1721                                        struct sk_buff_head *queue,
1722                                        struct inet_cork_full *cork,
1723                                        struct inet6_cork *v6_cork)
1724 {
1725         struct sk_buff *skb;
1726
1727         while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1728                 if (skb_dst(skb))
1729                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1730                                       IPSTATS_MIB_OUTDISCARDS);
1731                 kfree_skb(skb);
1732         }
1733
1734         ip6_cork_release(cork, v6_cork);
1735 }
1736
1737 void ip6_flush_pending_frames(struct sock *sk)
1738 {
1739         __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1740                                    &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1741 }
1742 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1743
1744 struct sk_buff *ip6_make_skb(struct sock *sk,
1745                              int getfrag(void *from, char *to, int offset,
1746                                          int len, int odd, struct sk_buff *skb),
1747                              void *from, int length, int transhdrlen,
1748                              int hlimit, int tclass,
1749                              struct ipv6_txoptions *opt, struct flowi6 *fl6,
1750                              struct rt6_info *rt, unsigned int flags,
1751                              int dontfrag)
1752 {
1753         struct inet_cork_full cork;
1754         struct inet6_cork v6_cork;
1755         struct sk_buff_head queue;
1756         int exthdrlen = (opt ? opt->opt_flen : 0);
1757         int err;
1758
1759         if (flags & MSG_PROBE)
1760                 return NULL;
1761
1762         __skb_queue_head_init(&queue);
1763
1764         cork.base.flags = 0;
1765         cork.base.addr = 0;
1766         cork.base.opt = NULL;
1767         v6_cork.opt = NULL;
1768         err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6);
1769         if (err)
1770                 return ERR_PTR(err);
1771
1772         if (dontfrag < 0)
1773                 dontfrag = inet6_sk(sk)->dontfrag;
1774
1775         err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
1776                                 &current->task_frag, getfrag, from,
1777                                 length + exthdrlen, transhdrlen + exthdrlen,
1778                                 flags, dontfrag);
1779         if (err) {
1780                 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
1781                 return ERR_PTR(err);
1782         }
1783
1784         return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
1785 }