kernel/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         int flags = 0;
 913
 914         /* The correct way to handle this would be to do
 915          * ip6_route_get_saddr, and then ip6_route_output; however,
 916          * the route-specific preferred source forces the
 917          * ip6_route_output call _before_ ip6_route_get_saddr.
 918          *
 919          * In source specific routing (no src=any default route),
 920          * ip6_route_output will fail given src=any saddr, though, so
 921          * that's why we try it again later.
 922          */
 923         if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
 924                 struct rt6_info *rt;
 925                 bool had_dst = *dst != NULL;
 926
 927                 if (!had_dst)
 928                         *dst = ip6_route_output(net, sk, fl6);
 929                 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
 930                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 931                                           sk ? inet6_sk(sk)->srcprefs : 0,
 932                                           &fl6->saddr);
 933                 if (err)
 934                         goto out_err_release;
 935
 936                 /* If we had an erroneous initial result, pretend it
 937                  * never existed and let the SA-enabled version take
 938                  * over.
 939                  */
 940                 if (!had_dst && (*dst)->error) {
 941                         dst_release(*dst);
 942                         *dst = NULL;
 943                 }
 944
 945                 if (fl6->flowi6_oif)
 946                         flags |= RT6_LOOKUP_F_IFACE;
 947         }
 948
 949         if (!*dst)
 950                 *dst = ip6_route_output_flags(net, sk, fl6, flags);
 951
 952         err = (*dst)->error;
 953         if (err)
 954                 goto out_err_release;
 955
 956 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 957         /*
 958          * Here if the dst entry we've looked up
 959          * has a neighbour entry that is in the INCOMPLETE
 960          * state and the src address from the flow is
 961          * marked as OPTIMISTIC, we release the found
 962          * dst entry and replace it instead with the
 963          * dst entry of the nexthop router
 964          */
 965         rt = (struct rt6_info *) *dst;
 966         rcu_read_lock_bh();
 967         n = __ipv6_neigh_lookup_noref(rt->dst.dev,
 968                                       rt6_nexthop(rt, &fl6->daddr));
 969         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 970         rcu_read_unlock_bh();
 971
 972         if (err) {
 973                 struct inet6_ifaddr *ifp;
 974                 struct flowi6 fl_gw6;
 975                 int redirect;
 976
 977                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 978                                       (*dst)->dev, 1);
 979
 980                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 981                 if (ifp)
 982                         in6_ifa_put(ifp);
 983
 984                 if (redirect) {
 985                         /*
 986                          * We need to get the dst entry for the
 987                          * default router instead
 988                          */
 989                         dst_release(*dst);
 990                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 991                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 992                         *dst = ip6_route_output(net, sk, &fl_gw6);
 993                         err = (*dst)->error;
 994                         if (err)
 995                                 goto out_err_release;
 996                 }
 997         }
 998 #endif
 999
1000         return 0;
1001
1002 out_err_release:
1003         if (err == -ENETUNREACH)
1004                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1005         dst_release(*dst);
1006         *dst = NULL;
1007         return err;
1008 }
1009
1010 /**
1011  *      ip6_dst_lookup - perform route lookup on flow
1012  *      @sk: socket which provides route info
1013  *      @dst: pointer to dst_entry * for result
1014  *      @fl6: flow to lookup
1015  *
1016  *      This function performs a route lookup on the given flow.
1017  *
1018  *      It returns zero on success, or a standard errno code on error.
1019  */
1020 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1021                    struct flowi6 *fl6)
1022 {
1023         *dst = NULL;
1024         return ip6_dst_lookup_tail(net, sk, dst, fl6);
1025 }
1026 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1027
1028 /**
1029  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1030  *      @sk: socket which provides route info
1031  *      @fl6: flow to lookup
1032  *      @final_dst: final destination address for ipsec lookup
1033  *
1034  *      This function performs a route lookup on the given flow.
1035  *
1036  *      It returns a valid dst pointer on success, or a pointer encoded
1037  *      error code.
1038  */
1039 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1040                                       const struct in6_addr *final_dst)
1041 {
1042         struct dst_entry *dst = NULL;
1043         int err;
1044
1045         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1046         if (err)
1047                 return ERR_PTR(err);
1048         if (final_dst)
1049                 fl6->daddr = *final_dst;
1050         if (!fl6->flowi6_oif)
1051                 fl6->flowi6_oif = l3mdev_fib_oif(dst->dev);
1052
1053         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1054 }
1055 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1056
1057 /**
1058  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1059  *      @sk: socket which provides the dst cache and route info
1060  *      @fl6: flow to lookup
1061  *      @final_dst: final destination address for ipsec lookup
1062  *
1063  *      This function performs a route lookup on the given flow with the
1064  *      possibility of using the cached route in the socket if it is valid.
1065  *      It will take the socket dst lock when operating on the dst cache.
1066  *      As a result, this function can only be used in process context.
1067  *
1068  *      It returns a valid dst pointer on success, or a pointer encoded
1069  *      error code.
1070  */
1071 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1072                                          const struct in6_addr *final_dst)
1073 {
1074         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1075
1076         dst = ip6_sk_dst_check(sk, dst, fl6);
1077         if (!dst)
1078                 dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
1079
1080         return dst;
1081 }
1082 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1083
1084 static inline int ip6_ufo_append_data(struct sock *sk,
1085                         struct sk_buff_head *queue,
1086                         int getfrag(void *from, char *to, int offset, int len,
1087                         int odd, struct sk_buff *skb),
1088                         void *from, int length, int hh_len, int fragheaderlen,
1089                         int exthdrlen, int transhdrlen, int mtu,
1090                         unsigned int flags, const struct flowi6 *fl6)
1091
1092 {
1093         struct sk_buff *skb;
1094         int err;
1095
1096         /* There is support for UDP large send offload by network
1097          * device, so create one single skb packet containing complete
1098          * udp datagram
1099          */
1100         skb = skb_peek_tail(queue);
1101         if (!skb) {
1102                 skb = sock_alloc_send_skb(sk,
1103                         hh_len + fragheaderlen + transhdrlen + 20,
1104                         (flags & MSG_DONTWAIT), &err);
1105                 if (!skb)
1106                         return err;
1107
1108                 /* reserve space for Hardware header */
1109                 skb_reserve(skb, hh_len);
1110
1111                 /* create space for UDP/IP header */
1112                 skb_put(skb, fragheaderlen + transhdrlen);
1113
1114                 /* initialize network header pointer */
1115                 skb_set_network_header(skb, exthdrlen);
1116
1117                 /* initialize protocol header pointer */
1118                 skb->transport_header = skb->network_header + fragheaderlen;
1119
1120                 skb->protocol = htons(ETH_P_IPV6);
1121                 skb->csum = 0;
1122
1123                 __skb_queue_tail(queue, skb);
1124         } else if (skb_is_gso(skb)) {
1125                 goto append;
1126         }
1127
1128         skb->ip_summed = CHECKSUM_PARTIAL;
1129         /* Specify the length of each IPv6 datagram fragment.
1130          * It has to be a multiple of 8.
1131          */
1132         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1133                                      sizeof(struct frag_hdr)) & ~7;
1134         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1135         skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk),
1136                                                          &fl6->daddr,
1137                                                          &fl6->saddr);
1138
1139 append:
1140         return skb_append_datato_frags(sk, skb, getfrag, from,
1141                                        (length - transhdrlen));
1142 }
1143
1144 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1145                                                gfp_t gfp)
1146 {
1147         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1148 }
1149
1150 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1151                                                 gfp_t gfp)
1152 {
1153         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1154 }
1155
1156 static void ip6_append_data_mtu(unsigned int *mtu,
1157                                 int *maxfraglen,
1158                                 unsigned int fragheaderlen,
1159                                 struct sk_buff *skb,
1160                                 struct rt6_info *rt,
1161                                 unsigned int orig_mtu)
1162 {
1163         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1164                 if (!skb) {
1165                         /* first fragment, reserve header_len */
1166                         *mtu = orig_mtu - rt->dst.header_len;
1167
1168                 } else {
1169                         /*
1170                          * this fragment is not first, the headers
1171                          * space is regarded as data space.
1172                          */
1173                         *mtu = orig_mtu;
1174                 }
1175                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1176                               + fragheaderlen - sizeof(struct frag_hdr);
1177         }
1178 }
1179
1180 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1181                           struct inet6_cork *v6_cork,
1182                           int hlimit, int tclass, struct ipv6_txoptions *opt,
1183                           struct rt6_info *rt, struct flowi6 *fl6)
1184 {
1185         struct ipv6_pinfo *np = inet6_sk(sk);
1186         unsigned int mtu;
1187
1188         /*
1189          * setup for corking
1190          */
1191         if (opt) {
1192                 if (WARN_ON(v6_cork->opt))
1193                         return -EINVAL;
1194
1195                 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1196                 if (unlikely(!v6_cork->opt))
1197                         return -ENOBUFS;
1198
1199                 v6_cork->opt->tot_len = opt->tot_len;
1200                 v6_cork->opt->opt_flen = opt->opt_flen;
1201                 v6_cork->opt->opt_nflen = opt->opt_nflen;
1202
1203                 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1204                                                     sk->sk_allocation);
1205                 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1206                         return -ENOBUFS;
1207
1208                 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1209                                                     sk->sk_allocation);
1210                 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1211                         return -ENOBUFS;
1212
1213                 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1214                                                    sk->sk_allocation);
1215                 if (opt->hopopt && !v6_cork->opt->hopopt)
1216                         return -ENOBUFS;
1217
1218                 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1219                                                     sk->sk_allocation);
1220                 if (opt->srcrt && !v6_cork->opt->srcrt)
1221                         return -ENOBUFS;
1222
1223                 /* need source address above miyazawa*/
1224         }
1225         dst_hold(&rt->dst);
1226         cork->base.dst = &rt->dst;
1227         cork->fl.u.ip6 = *fl6;
1228         v6_cork->hop_limit = hlimit;
1229         v6_cork->tclass = tclass;
1230         if (rt->dst.flags & DST_XFRM_TUNNEL)
1231                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1232                       rt->dst.dev->mtu : dst_mtu(&rt->dst);
1233         else
1234                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1235                       rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1236         if (np->frag_size < mtu) {
1237                 if (np->frag_size)
1238                         mtu = np->frag_size;
1239         }
1240         cork->base.fragsize = mtu;
1241         if (dst_allfrag(rt->dst.path))
1242                 cork->base.flags |= IPCORK_ALLFRAG;
1243         cork->base.length = 0;
1244
1245         return 0;
1246 }
1247
1248 static int __ip6_append_data(struct sock *sk,
1249                              struct flowi6 *fl6,
1250                              struct sk_buff_head *queue,
1251                              struct inet_cork *cork,
1252                              struct inet6_cork *v6_cork,
1253                              struct page_frag *pfrag,
1254                              int getfrag(void *from, char *to, int offset,
1255                                          int len, int odd, struct sk_buff *skb),
1256                              void *from, int length, int transhdrlen,
1257                              unsigned int flags, int dontfrag)
1258 {
1259         struct sk_buff *skb, *skb_prev = NULL;
1260         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1261         int exthdrlen = 0;
1262         int dst_exthdrlen = 0;
1263         int hh_len;
1264         int copy;
1265         int err;
1266         int offset = 0;
1267         __u8 tx_flags = 0;
1268         u32 tskey = 0;
1269         struct rt6_info *rt = (struct rt6_info *)cork->dst;
1270         struct ipv6_txoptions *opt = v6_cork->opt;
1271         int csummode = CHECKSUM_NONE;
1272         unsigned int maxnonfragsize, headersize;
1273
1274         skb = skb_peek_tail(queue);
1275         if (!skb) {
1276                 exthdrlen = opt ? opt->opt_flen : 0;
1277                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1278         }
1279
1280         mtu = cork->fragsize;
1281         orig_mtu = mtu;
1282
1283         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1284
1285         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1286                         (opt ? opt->opt_nflen : 0);
1287         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1288                      sizeof(struct frag_hdr);
1289
1290         headersize = sizeof(struct ipv6hdr) +
1291                      (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1292                      (dst_allfrag(&rt->dst) ?
1293                       sizeof(struct frag_hdr) : 0) +
1294                      rt->rt6i_nfheader_len;
1295
1296         if (cork->length + length > mtu - headersize && dontfrag &&
1297             (sk->sk_protocol == IPPROTO_UDP ||
1298              sk->sk_protocol == IPPROTO_RAW)) {
1299                 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1300                                 sizeof(struct ipv6hdr));
1301                 goto emsgsize;
1302         }
1303
1304         if (ip6_sk_ignore_df(sk))
1305                 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1306         else
1307                 maxnonfragsize = mtu;
1308
1309         if (cork->length + length > maxnonfragsize - headersize) {
1310 emsgsize:
1311                 ipv6_local_error(sk, EMSGSIZE, fl6,
1312                                  mtu - headersize +
1313                                  sizeof(struct ipv6hdr));
1314                 return -EMSGSIZE;
1315         }
1316
1317         /* CHECKSUM_PARTIAL only with no extension headers and when
1318          * we are not going to fragment
1319          */
1320         if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1321             headersize == sizeof(struct ipv6hdr) &&
1322             length < mtu - headersize &&
1323             !(flags & MSG_MORE) &&
1324             rt->dst.dev->features & NETIF_F_V6_CSUM)
1325                 csummode = CHECKSUM_PARTIAL;
1326
1327         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1328                 sock_tx_timestamp(sk, &tx_flags);
1329                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1330                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1331                         tskey = sk->sk_tskey++;
1332         }
1333
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) && !udp_get_no_check6_tx(sk)) {
1356                 err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
1357                                           hh_len, fragheaderlen, exthdrlen,
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 }