net/ipv6/ip6_output.c

   1 /*
   2  *      IPv6 output functions
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on linux/net/ipv4/ip_output.c
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  *
  15  *      Changes:
  16  *      A.N.Kuznetsov   :       airthmetics in fragmentation.
  17  *                              extension headers are implemented.
  18  *                              route changes now work.
  19  *                              ip6_forward does not confuse sniffers.
  20  *                              etc.
  21  *
  22  *      H. von Brand    :       Added missing #include <linux/string.h>
  23  *      Imran Patel     :       frag id should be in NBO
  24  *      Kazunori MIYAZAWA @USAGI
  25  *                      :       add ip6_append_data and related functions
  26  *                              for datagram xmit
  27  */
  28
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/string.h>
  32 #include <linux/socket.h>
  33 #include <linux/net.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/if_arp.h>
  36 #include <linux/in6.h>
  37 #include <linux/tcp.h>
  38 #include <linux/route.h>
  39 #include <linux/module.h>
  40 #include <linux/slab.h>
  41
  42 #include <linux/netfilter.h>
  43 #include <linux/netfilter_ipv6.h>
  44
  45 #include <net/sock.h>
  46 #include <net/snmp.h>
  47
  48 #include <net/ipv6.h>
  49 #include <net/ndisc.h>
  50 #include <net/protocol.h>
  51 #include <net/ip6_route.h>
  52 #include <net/addrconf.h>
  53 #include <net/rawv6.h>
  54 #include <net/icmp.h>
  55 #include <net/xfrm.h>
  56 #include <net/checksum.h>
  57 #include <linux/mroute6.h>
  58
  59 static int ip6_finish_output2(struct sk_buff *skb)
  60 {
  61         struct dst_entry *dst = skb_dst(skb);
  62         struct net_device *dev = dst->dev;
  63         struct neighbour *neigh;
  64         struct in6_addr *nexthop;
  65         int ret;
  66
  67         skb->protocol = htons(ETH_P_IPV6);
  68         skb->dev = dev;
  69
  70         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
  71                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
  72
  73                 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&
  74                     ((mroute6_socket(dev_net(dev), skb) &&
  75                      !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
  76                      ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
  77                                          &ipv6_hdr(skb)->saddr))) {
  78                         struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  79
  80                         /* Do not check for IFF_ALLMULTI; multicast routing
  81                            is not supported in any case.
  82                          */
  83                         if (newskb)
  84                                 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  85                                         newskb, NULL, newskb->dev,
  86                                         dev_loopback_xmit);
  87
  88                         if (ipv6_hdr(skb)->hop_limit == 0) {
  89                                 IP6_INC_STATS(dev_net(dev), idev,
  90                                               IPSTATS_MIB_OUTDISCARDS);
  91                                 kfree_skb(skb);
  92                                 return 0;
  93                         }
  94                 }
  95
  96                 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST,
  97                                 skb->len);
  98
  99                 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
 100                     IPV6_ADDR_SCOPE_NODELOCAL &&
 101                     !(dev->flags & IFF_LOOPBACK)) {
 102                         kfree_skb(skb);
 103                         return 0;
 104                 }
 105         }
 106
 107         rcu_read_lock_bh();
 108         nexthop = rt6_nexthop((struct rt6_info *)dst);
 109         neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
 110         if (unlikely(!neigh))
 111                 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
 112         if (!IS_ERR(neigh)) {
 113                 ret = dst_neigh_output(dst, neigh, skb);
 114                 rcu_read_unlock_bh();
 115                 return ret;
 116         }
 117         rcu_read_unlock_bh();
 118
 119         IP6_INC_STATS(dev_net(dst->dev),
 120                       ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 121         kfree_skb(skb);
 122         return -EINVAL;
 123 }
 124
 125 static int ip6_finish_output(struct sk_buff *skb)
 126 {
 127         if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
 128             dst_allfrag(skb_dst(skb)) ||
 129             (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 130                 return ip6_fragment(skb, ip6_finish_output2);
 131         else
 132                 return ip6_finish_output2(skb);
 133 }
 134
 135 int ip6_output(struct sk_buff *skb)
 136 {
 137         struct net_device *dev = skb_dst(skb)->dev;
 138         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(dev_net(dev), idev,
 141                               IPSTATS_MIB_OUTDISCARDS);
 142                 kfree_skb(skb);
 143                 return 0;
 144         }
 145
 146         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
 147                             ip6_finish_output,
 148                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 149 }
 150
 151 /*
 152  *      xmit an sk_buff (used by TCP, SCTP and DCCP)
 153  */
 154
 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 156              struct ipv6_txoptions *opt, int tclass)
 157 {
 158         struct net *net = sock_net(sk);
 159         struct ipv6_pinfo *np = inet6_sk(sk);
 160         struct in6_addr *first_hop = &fl6->daddr;
 161         struct dst_entry *dst = skb_dst(skb);
 162         struct ipv6hdr *hdr;
 163         u8  proto = fl6->flowi6_proto;
 164         int seg_len = skb->len;
 165         int hlimit = -1;
 166         u32 mtu;
 167
 168         if (opt) {
 169                 unsigned int head_room;
 170
 171                 /* First: exthdrs may take lots of space (~8K for now)
 172                    MAX_HEADER is not enough.
 173                  */
 174                 head_room = opt->opt_nflen + opt->opt_flen;
 175                 seg_len += head_room;
 176                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 177
 178                 if (skb_headroom(skb) < head_room) {
 179                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 180                         if (skb2 == NULL) {
 181                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 182                                               IPSTATS_MIB_OUTDISCARDS);
 183                                 kfree_skb(skb);
 184                                 return -ENOBUFS;
 185                         }
 186                         consume_skb(skb);
 187                         skb = skb2;
 188                         skb_set_owner_w(skb, sk);
 189                 }
 190                 if (opt->opt_flen)
 191                         ipv6_push_frag_opts(skb, opt, &proto);
 192                 if (opt->opt_nflen)
 193                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 194         }
 195
 196         skb_push(skb, sizeof(struct ipv6hdr));
 197         skb_reset_network_header(skb);
 198         hdr = ipv6_hdr(skb);
 199
 200         /*
 201          *      Fill in the IPv6 header
 202          */
 203         if (np)
 204                 hlimit = np->hop_limit;
 205         if (hlimit < 0)
 206                 hlimit = ip6_dst_hoplimit(dst);
 207
 208         ip6_flow_hdr(hdr, tclass, fl6->flowlabel);
 209
 210         hdr->payload_len = htons(seg_len);
 211         hdr->nexthdr = proto;
 212         hdr->hop_limit = hlimit;
 213
 214         hdr->saddr = fl6->saddr;
 215         hdr->daddr = *first_hop;
 216
 217         skb->protocol = htons(ETH_P_IPV6);
 218         skb->priority = sk->sk_priority;
 219         skb->mark = sk->sk_mark;
 220
 221         mtu = dst_mtu(dst);
 222         if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
 223                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 224                               IPSTATS_MIB_OUT, skb->len);
 225                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 226                                dst->dev, dst_output);
 227         }
 228
 229         skb->dev = dst->dev;
 230         ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
 231         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 232         kfree_skb(skb);
 233         return -EMSGSIZE;
 234 }
 235
 236 EXPORT_SYMBOL(ip6_xmit);
 237
 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 239 {
 240         struct ip6_ra_chain *ra;
 241         struct sock *last = NULL;
 242
 243         read_lock(&ip6_ra_lock);
 244         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 245                 struct sock *sk = ra->sk;
 246                 if (sk && ra->sel == sel &&
 247                     (!sk->sk_bound_dev_if ||
 248                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 249                         if (last) {
 250                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 251                                 if (skb2)
 252                                         rawv6_rcv(last, skb2);
 253                         }
 254                         last = sk;
 255                 }
 256         }
 257
 258         if (last) {
 259                 rawv6_rcv(last, skb);
 260                 read_unlock(&ip6_ra_lock);
 261                 return 1;
 262         }
 263         read_unlock(&ip6_ra_lock);
 264         return 0;
 265 }
 266
 267 static int ip6_forward_proxy_check(struct sk_buff *skb)
 268 {
 269         struct ipv6hdr *hdr = ipv6_hdr(skb);
 270         u8 nexthdr = hdr->nexthdr;
 271         __be16 frag_off;
 272         int offset;
 273
 274         if (ipv6_ext_hdr(nexthdr)) {
 275                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 276                 if (offset < 0)
 277                         return 0;
 278         } else
 279                 offset = sizeof(struct ipv6hdr);
 280
 281         if (nexthdr == IPPROTO_ICMPV6) {
 282                 struct icmp6hdr *icmp6;
 283
 284                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 285                                          offset + 1 - skb->data)))
 286                         return 0;
 287
 288                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 289
 290                 switch (icmp6->icmp6_type) {
 291                 case NDISC_ROUTER_SOLICITATION:
 292                 case NDISC_ROUTER_ADVERTISEMENT:
 293                 case NDISC_NEIGHBOUR_SOLICITATION:
 294                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 295                 case NDISC_REDIRECT:
 296                         /* For reaction involving unicast neighbor discovery
 297                          * message destined to the proxied address, pass it to
 298                          * input function.
 299                          */
 300                         return 1;
 301                 default:
 302                         break;
 303                 }
 304         }
 305
 306         /*
 307          * The proxying router can't forward traffic sent to a link-local
 308          * address, so signal the sender and discard the packet. This
 309          * behavior is clarified by the MIPv6 specification.
 310          */
 311         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 312                 dst_link_failure(skb);
 313                 return -1;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static inline int ip6_forward_finish(struct sk_buff *skb)
 320 {
 321         return dst_output(skb);
 322 }
 323
 324 int ip6_forward(struct sk_buff *skb)
 325 {
 326         struct dst_entry *dst = skb_dst(skb);
 327         struct ipv6hdr *hdr = ipv6_hdr(skb);
 328         struct inet6_skb_parm *opt = IP6CB(skb);
 329         struct net *net = dev_net(dst->dev);
 330         u32 mtu;
 331
 332         if (net->ipv6.devconf_all->forwarding == 0)
 333                 goto error;
 334
 335         if (skb_warn_if_lro(skb))
 336                 goto drop;
 337
 338         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 339                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 340                 goto drop;
 341         }
 342
 343         if (skb->pkt_type != PACKET_HOST)
 344                 goto drop;
 345
 346         skb_forward_csum(skb);
 347
 348         /*
 349          *      We DO NOT make any processing on
 350          *      RA packets, pushing them to user level AS IS
 351          *      without ane WARRANTY that application will be able
 352          *      to interpret them. The reason is that we
 353          *      cannot make anything clever here.
 354          *
 355          *      We are not end-node, so that if packet contains
 356          *      AH/ESP, we cannot make anything.
 357          *      Defragmentation also would be mistake, RA packets
 358          *      cannot be fragmented, because there is no warranty
 359          *      that different fragments will go along one path. --ANK
 360          */
 361         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 362                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 363                         return 0;
 364         }
 365
 366         /*
 367          *      check and decrement ttl
 368          */
 369         if (hdr->hop_limit <= 1) {
 370                 /* Force OUTPUT device used as source address */
 371                 skb->dev = dst->dev;
 372                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 373                 IP6_INC_STATS_BH(net,
 374                                  ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 375
 376                 kfree_skb(skb);
 377                 return -ETIMEDOUT;
 378         }
 379
 380         /* XXX: idev->cnf.proxy_ndp? */
 381         if (net->ipv6.devconf_all->proxy_ndp &&
 382             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 383                 int proxied = ip6_forward_proxy_check(skb);
 384                 if (proxied > 0)
 385                         return ip6_input(skb);
 386                 else if (proxied < 0) {
 387                         IP6_INC_STATS(net, ip6_dst_idev(dst),
 388                                       IPSTATS_MIB_INDISCARDS);
 389                         goto drop;
 390                 }
 391         }
 392
 393         if (!xfrm6_route_forward(skb)) {
 394                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 395                 goto drop;
 396         }
 397         dst = skb_dst(skb);
 398
 399         /* IPv6 specs say nothing about it, but it is clear that we cannot
 400            send redirects to source routed frames.
 401            We don't send redirects to frames decapsulated from IPsec.
 402          */
 403         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 404                 struct in6_addr *target = NULL;
 405                 struct inet_peer *peer;
 406                 struct rt6_info *rt;
 407
 408                 /*
 409                  *      incoming and outgoing devices are the same
 410                  *      send a redirect.
 411                  */
 412
 413                 rt = (struct rt6_info *) dst;
 414                 if (rt->rt6i_flags & RTF_GATEWAY)
 415                         target = &rt->rt6i_gateway;
 416                 else
 417                         target = &hdr->daddr;
 418
 419                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 420
 421                 /* Limit redirects both by destination (here)
 422                    and by source (inside ndisc_send_redirect)
 423                  */
 424                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 425                         ndisc_send_redirect(skb, target);
 426                 if (peer)
 427                         inet_putpeer(peer);
 428         } else {
 429                 int addrtype = ipv6_addr_type(&hdr->saddr);
 430
 431                 /* This check is security critical. */
 432                 if (addrtype == IPV6_ADDR_ANY ||
 433                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 434                         goto error;
 435                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 436                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 437                                     ICMPV6_NOT_NEIGHBOUR, 0);
 438                         goto error;
 439                 }
 440         }
 441
 442         mtu = dst_mtu(dst);
 443         if (mtu < IPV6_MIN_MTU)
 444                 mtu = IPV6_MIN_MTU;
 445
 446         if ((!skb->local_df && skb->len > mtu && !skb_is_gso(skb)) ||
 447             (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)) {
 448                 /* Again, force OUTPUT device used as source address */
 449                 skb->dev = dst->dev;
 450                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 451                 IP6_INC_STATS_BH(net,
 452                                  ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
 453                 IP6_INC_STATS_BH(net,
 454                                  ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
 455                 kfree_skb(skb);
 456                 return -EMSGSIZE;
 457         }
 458
 459         if (skb_cow(skb, dst->dev->hard_header_len)) {
 460                 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
 461                 goto drop;
 462         }
 463
 464         hdr = ipv6_hdr(skb);
 465
 466         /* Mangling hops number delayed to point after skb COW */
 467
 468         hdr->hop_limit--;
 469
 470         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 471         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 472         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 473                        ip6_forward_finish);
 474
 475 error:
 476         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 477 drop:
 478         kfree_skb(skb);
 479         return -EINVAL;
 480 }
 481
 482 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 483 {
 484         to->pkt_type = from->pkt_type;
 485         to->priority = from->priority;
 486         to->protocol = from->protocol;
 487         skb_dst_drop(to);
 488         skb_dst_set(to, dst_clone(skb_dst(from)));
 489         to->dev = from->dev;
 490         to->mark = from->mark;
 491
 492 #ifdef CONFIG_NET_SCHED
 493         to->tc_index = from->tc_index;
 494 #endif
 495         nf_copy(to, from);
 496 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 497         to->nf_trace = from->nf_trace;
 498 #endif
 499         skb_copy_secmark(to, from);
 500 }
 501
 502 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 503 {
 504         struct sk_buff *frag;
 505         struct rt6_info *rt = (struct rt6_info*)skb_dst(skb);
 506         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 507         struct ipv6hdr *tmp_hdr;
 508         struct frag_hdr *fh;
 509         unsigned int mtu, hlen, left, len;
 510         int hroom, troom;
 511         __be32 frag_id = 0;
 512         int ptr, offset = 0, err=0;
 513         u8 *prevhdr, nexthdr = 0;
 514         struct net *net = dev_net(skb_dst(skb)->dev);
 515
 516         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 517         nexthdr = *prevhdr;
 518
 519         mtu = ip6_skb_dst_mtu(skb);
 520
 521         /* We must not fragment if the socket is set to force MTU discovery
 522          * or if the skb it not generated by a local socket.
 523          */
 524         if (unlikely(!skb->local_df && skb->len > mtu) ||
 525                      (IP6CB(skb)->frag_max_size &&
 526                       IP6CB(skb)->frag_max_size > mtu)) {
 527                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 528                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 529
 530                 skb->dev = skb_dst(skb)->dev;
 531                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 532                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 533                               IPSTATS_MIB_FRAGFAILS);
 534                 kfree_skb(skb);
 535                 return -EMSGSIZE;
 536         }
 537
 538         if (np && np->frag_size < mtu) {
 539                 if (np->frag_size)
 540                         mtu = np->frag_size;
 541         }
 542         mtu -= hlen + sizeof(struct frag_hdr);
 543
 544         if (skb_has_frag_list(skb)) {
 545                 int first_len = skb_pagelen(skb);
 546                 struct sk_buff *frag2;
 547
 548                 if (first_len - hlen > mtu ||
 549                     ((first_len - hlen) & 7) ||
 550                     skb_cloned(skb))
 551                         goto slow_path;
 552
 553                 skb_walk_frags(skb, frag) {
 554                         /* Correct geometry. */
 555                         if (frag->len > mtu ||
 556                             ((frag->len & 7) && frag->next) ||
 557                             skb_headroom(frag) < hlen)
 558                                 goto slow_path_clean;
 559
 560                         /* Partially cloned skb? */
 561                         if (skb_shared(frag))
 562                                 goto slow_path_clean;
 563
 564                         BUG_ON(frag->sk);
 565                         if (skb->sk) {
 566                                 frag->sk = skb->sk;
 567                                 frag->destructor = sock_wfree;
 568                         }
 569                         skb->truesize -= frag->truesize;
 570                 }
 571
 572                 err = 0;
 573                 offset = 0;
 574                 frag = skb_shinfo(skb)->frag_list;
 575                 skb_frag_list_init(skb);
 576                 /* BUILD HEADER */
 577
 578                 *prevhdr = NEXTHDR_FRAGMENT;
 579                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 580                 if (!tmp_hdr) {
 581                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 582                                       IPSTATS_MIB_FRAGFAILS);
 583                         return -ENOMEM;
 584                 }
 585
 586                 __skb_pull(skb, hlen);
 587                 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
 588                 __skb_push(skb, hlen);
 589                 skb_reset_network_header(skb);
 590                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 591
 592                 ipv6_select_ident(fh, rt);
 593                 fh->nexthdr = nexthdr;
 594                 fh->reserved = 0;
 595                 fh->frag_off = htons(IP6_MF);
 596                 frag_id = fh->identification;
 597
 598                 first_len = skb_pagelen(skb);
 599                 skb->data_len = first_len - skb_headlen(skb);
 600                 skb->len = first_len;
 601                 ipv6_hdr(skb)->payload_len = htons(first_len -
 602                                                    sizeof(struct ipv6hdr));
 603
 604                 dst_hold(&rt->dst);
 605
 606                 for (;;) {
 607                         /* Prepare header of the next frame,
 608                          * before previous one went down. */
 609                         if (frag) {
 610                                 frag->ip_summed = CHECKSUM_NONE;
 611                                 skb_reset_transport_header(frag);
 612                                 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 613                                 __skb_push(frag, hlen);
 614                                 skb_reset_network_header(frag);
 615                                 memcpy(skb_network_header(frag), tmp_hdr,
 616                                        hlen);
 617                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 618                                 fh->nexthdr = nexthdr;
 619                                 fh->reserved = 0;
 620                                 fh->frag_off = htons(offset);
 621                                 if (frag->next != NULL)
 622                                         fh->frag_off |= htons(IP6_MF);
 623                                 fh->identification = frag_id;
 624                                 ipv6_hdr(frag)->payload_len =
 625                                                 htons(frag->len -
 626                                                       sizeof(struct ipv6hdr));
 627                                 ip6_copy_metadata(frag, skb);
 628                         }
 629
 630                         err = output(skb);
 631                         if(!err)
 632                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 633                                               IPSTATS_MIB_FRAGCREATES);
 634
 635                         if (err || !frag)
 636                                 break;
 637
 638                         skb = frag;
 639                         frag = skb->next;
 640                         skb->next = NULL;
 641                 }
 642
 643                 kfree(tmp_hdr);
 644
 645                 if (err == 0) {
 646                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 647                                       IPSTATS_MIB_FRAGOKS);
 648                         ip6_rt_put(rt);
 649                         return 0;
 650                 }
 651
 652                 while (frag) {
 653                         skb = frag->next;
 654                         kfree_skb(frag);
 655                         frag = skb;
 656                 }
 657
 658                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 659                               IPSTATS_MIB_FRAGFAILS);
 660                 ip6_rt_put(rt);
 661                 return err;
 662
 663 slow_path_clean:
 664                 skb_walk_frags(skb, frag2) {
 665                         if (frag2 == frag)
 666                                 break;
 667                         frag2->sk = NULL;
 668                         frag2->destructor = NULL;
 669                         skb->truesize += frag2->truesize;
 670                 }
 671         }
 672
 673 slow_path:
 674         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 675             skb_checksum_help(skb))
 676                 goto fail;
 677
 678         left = skb->len - hlen;         /* Space per frame */
 679         ptr = hlen;                     /* Where to start from */
 680
 681         /*
 682          *      Fragment the datagram.
 683          */
 684
 685         *prevhdr = NEXTHDR_FRAGMENT;
 686         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 687         troom = rt->dst.dev->needed_tailroom;
 688
 689         /*
 690          *      Keep copying data until we run out.
 691          */
 692         while(left > 0) {
 693                 len = left;
 694                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 695                 if (len > mtu)
 696                         len = mtu;
 697                 /* IF: we are not sending up to and including the packet end
 698                    then align the next start on an eight byte boundary */
 699                 if (len < left) {
 700                         len &= ~7;
 701                 }
 702                 /*
 703                  *      Allocate buffer.
 704                  */
 705
 706                 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 707                                       hroom + troom, GFP_ATOMIC)) == NULL) {
 708                         NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 709                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 710                                       IPSTATS_MIB_FRAGFAILS);
 711                         err = -ENOMEM;
 712                         goto fail;
 713                 }
 714
 715                 /*
 716                  *      Set up data on packet
 717                  */
 718
 719                 ip6_copy_metadata(frag, skb);
 720                 skb_reserve(frag, hroom);
 721                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 722                 skb_reset_network_header(frag);
 723                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 724                 frag->transport_header = (frag->network_header + hlen +
 725                                           sizeof(struct frag_hdr));
 726
 727                 /*
 728                  *      Charge the memory for the fragment to any owner
 729                  *      it might possess
 730                  */
 731                 if (skb->sk)
 732                         skb_set_owner_w(frag, skb->sk);
 733
 734                 /*
 735                  *      Copy the packet header into the new buffer.
 736                  */
 737                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 738
 739                 /*
 740                  *      Build fragment header.
 741                  */
 742                 fh->nexthdr = nexthdr;
 743                 fh->reserved = 0;
 744                 if (!frag_id) {
 745                         ipv6_select_ident(fh, rt);
 746                         frag_id = fh->identification;
 747                 } else
 748                         fh->identification = frag_id;
 749
 750                 /*
 751                  *      Copy a block of the IP datagram.
 752                  */
 753                 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
 754                         BUG();
 755                 left -= len;
 756
 757                 fh->frag_off = htons(offset);
 758                 if (left > 0)
 759                         fh->frag_off |= htons(IP6_MF);
 760                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 761                                                     sizeof(struct ipv6hdr));
 762
 763                 ptr += len;
 764                 offset += len;
 765
 766                 /*
 767                  *      Put this fragment into the sending queue.
 768                  */
 769                 err = output(frag);
 770                 if (err)
 771                         goto fail;
 772
 773                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 774                               IPSTATS_MIB_FRAGCREATES);
 775         }
 776         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 777                       IPSTATS_MIB_FRAGOKS);
 778         consume_skb(skb);
 779         return err;
 780
 781 fail:
 782         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 783                       IPSTATS_MIB_FRAGFAILS);
 784         kfree_skb(skb);
 785         return err;
 786 }
 787
 788 static inline int ip6_rt_check(const struct rt6key *rt_key,
 789                                const struct in6_addr *fl_addr,
 790                                const struct in6_addr *addr_cache)
 791 {
 792         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 793                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 794 }
 795
 796 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 797                                           struct dst_entry *dst,
 798                                           const struct flowi6 *fl6)
 799 {
 800         struct ipv6_pinfo *np = inet6_sk(sk);
 801         struct rt6_info *rt;
 802
 803         if (!dst)
 804                 goto out;
 805
 806         if (dst->ops->family != AF_INET6) {
 807                 dst_release(dst);
 808                 return NULL;
 809         }
 810
 811         rt = (struct rt6_info *)dst;
 812         /* Yes, checking route validity in not connected
 813          * case is not very simple. Take into account,
 814          * that we do not support routing by source, TOS,
 815          * and MSG_DONTROUTE            --ANK (980726)
 816          *
 817          * 1. ip6_rt_check(): If route was host route,
 818          *    check that cached destination is current.
 819          *    If it is network route, we still may
 820          *    check its validity using saved pointer
 821          *    to the last used address: daddr_cache.
 822          *    We do not want to save whole address now,
 823          *    (because main consumer of this service
 824          *    is tcp, which has not this problem),
 825          *    so that the last trick works only on connected
 826          *    sockets.
 827          * 2. oif also should be the same.
 828          */
 829         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 830 #ifdef CONFIG_IPV6_SUBTREES
 831             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 832 #endif
 833             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 834                 dst_release(dst);
 835                 dst = NULL;
 836         }
 837
 838 out:
 839         return dst;
 840 }
 841
 842 static int ip6_dst_lookup_tail(struct sock *sk,
 843                                struct dst_entry **dst, struct flowi6 *fl6)
 844 {
 845         struct net *net = sock_net(sk);
 846 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 847         struct neighbour *n;
 848         struct rt6_info *rt;
 849 #endif
 850         int err;
 851
 852         if (*dst == NULL)
 853                 *dst = ip6_route_output(net, sk, fl6);
 854
 855         if ((err = (*dst)->error))
 856                 goto out_err_release;
 857
 858         if (ipv6_addr_any(&fl6->saddr)) {
 859                 struct rt6_info *rt = (struct rt6_info *) *dst;
 860                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 861                                           sk ? inet6_sk(sk)->srcprefs : 0,
 862                                           &fl6->saddr);
 863                 if (err)
 864                         goto out_err_release;
 865         }
 866
 867 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 868         /*
 869          * Here if the dst entry we've looked up
 870          * has a neighbour entry that is in the INCOMPLETE
 871          * state and the src address from the flow is
 872          * marked as OPTIMISTIC, we release the found
 873          * dst entry and replace it instead with the
 874          * dst entry of the nexthop router
 875          */
 876         rt = (struct rt6_info *) *dst;
 877         rcu_read_lock_bh();
 878         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
 879         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 880         rcu_read_unlock_bh();
 881
 882         if (err) {
 883                 struct inet6_ifaddr *ifp;
 884                 struct flowi6 fl_gw6;
 885                 int redirect;
 886
 887                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 888                                       (*dst)->dev, 1);
 889
 890                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 891                 if (ifp)
 892                         in6_ifa_put(ifp);
 893
 894                 if (redirect) {
 895                         /*
 896                          * We need to get the dst entry for the
 897                          * default router instead
 898                          */
 899                         dst_release(*dst);
 900                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 901                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 902                         *dst = ip6_route_output(net, sk, &fl_gw6);
 903                         if ((err = (*dst)->error))
 904                                 goto out_err_release;
 905                 }
 906         }
 907 #endif
 908
 909         return 0;
 910
 911 out_err_release:
 912         if (err == -ENETUNREACH)
 913                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 914         dst_release(*dst);
 915         *dst = NULL;
 916         return err;
 917 }
 918
 919 /**
 920  *      ip6_dst_lookup - perform route lookup on flow
 921  *      @sk: socket which provides route info
 922  *      @dst: pointer to dst_entry * for result
 923  *      @fl6: flow to lookup
 924  *
 925  *      This function performs a route lookup on the given flow.
 926  *
 927  *      It returns zero on success, or a standard errno code on error.
 928  */
 929 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 930 {
 931         *dst = NULL;
 932         return ip6_dst_lookup_tail(sk, dst, fl6);
 933 }
 934 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 935
 936 /**
 937  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 938  *      @sk: socket which provides route info
 939  *      @fl6: flow to lookup
 940  *      @final_dst: final destination address for ipsec lookup
 941  *      @can_sleep: we are in a sleepable context
 942  *
 943  *      This function performs a route lookup on the given flow.
 944  *
 945  *      It returns a valid dst pointer on success, or a pointer encoded
 946  *      error code.
 947  */
 948 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 949                                       const struct in6_addr *final_dst,
 950                                       bool can_sleep)
 951 {
 952         struct dst_entry *dst = NULL;
 953         int err;
 954
 955         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 956         if (err)
 957                 return ERR_PTR(err);
 958         if (final_dst)
 959                 fl6->daddr = *final_dst;
 960         if (can_sleep)
 961                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
 962
 963         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
 964 }
 965 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 966
 967 /**
 968  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
 969  *      @sk: socket which provides the dst cache and route info
 970  *      @fl6: flow to lookup
 971  *      @final_dst: final destination address for ipsec lookup
 972  *      @can_sleep: we are in a sleepable context
 973  *
 974  *      This function performs a route lookup on the given flow with the
 975  *      possibility of using the cached route in the socket if it is valid.
 976  *      It will take the socket dst lock when operating on the dst cache.
 977  *      As a result, this function can only be used in process context.
 978  *
 979  *      It returns a valid dst pointer on success, or a pointer encoded
 980  *      error code.
 981  */
 982 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 983                                          const struct in6_addr *final_dst,
 984                                          bool can_sleep)
 985 {
 986         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
 987         int err;
 988
 989         dst = ip6_sk_dst_check(sk, dst, fl6);
 990
 991         err = ip6_dst_lookup_tail(sk, &dst, fl6);
 992         if (err)
 993                 return ERR_PTR(err);
 994         if (final_dst)
 995                 fl6->daddr = *final_dst;
 996         if (can_sleep)
 997                 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
 998
 999         return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1000 }
1001 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1002
1003 static inline int ip6_ufo_append_data(struct sock *sk,
1004                         int getfrag(void *from, char *to, int offset, int len,
1005                         int odd, struct sk_buff *skb),
1006                         void *from, int length, int hh_len, int fragheaderlen,
1007                         int transhdrlen, int mtu,unsigned int flags,
1008                         struct rt6_info *rt)
1009
1010 {
1011         struct sk_buff *skb;
1012         struct frag_hdr fhdr;
1013         int err;
1014
1015         /* There is support for UDP large send offload by network
1016          * device, so create one single skb packet containing complete
1017          * udp datagram
1018          */
1019         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1020                 skb = sock_alloc_send_skb(sk,
1021                         hh_len + fragheaderlen + transhdrlen + 20,
1022                         (flags & MSG_DONTWAIT), &err);
1023                 if (skb == NULL)
1024                         return err;
1025
1026                 /* reserve space for Hardware header */
1027                 skb_reserve(skb, hh_len);
1028
1029                 /* create space for UDP/IP header */
1030                 skb_put(skb,fragheaderlen + transhdrlen);
1031
1032                 /* initialize network header pointer */
1033                 skb_reset_network_header(skb);
1034
1035                 /* initialize protocol header pointer */
1036                 skb->transport_header = skb->network_header + fragheaderlen;
1037
1038                 skb->protocol = htons(ETH_P_IPV6);
1039                 skb->csum = 0;
1040
1041                 __skb_queue_tail(&sk->sk_write_queue, skb);
1042         } else if (skb_is_gso(skb)) {
1043                 goto append;
1044         }
1045
1046         skb->ip_summed = CHECKSUM_PARTIAL;
1047         /* Specify the length of each IPv6 datagram fragment.
1048          * It has to be a multiple of 8.
1049          */
1050         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1051                                      sizeof(struct frag_hdr)) & ~7;
1052         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1053         ipv6_select_ident(&fhdr, rt);
1054         skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1055
1056 append:
1057         return skb_append_datato_frags(sk, skb, getfrag, from,
1058                                        (length - transhdrlen));
1059 }
1060
1061 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1062                                                gfp_t gfp)
1063 {
1064         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1065 }
1066
1067 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1068                                                 gfp_t gfp)
1069 {
1070         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1071 }
1072
1073 static void ip6_append_data_mtu(unsigned int *mtu,
1074                                 int *maxfraglen,
1075                                 unsigned int fragheaderlen,
1076                                 struct sk_buff *skb,
1077                                 struct rt6_info *rt,
1078                                 bool pmtuprobe)
1079 {
1080         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1081                 if (skb == NULL) {
1082                         /* first fragment, reserve header_len */
1083                         *mtu = *mtu - rt->dst.header_len;
1084
1085                 } else {
1086                         /*
1087                          * this fragment is not first, the headers
1088                          * space is regarded as data space.
1089                          */
1090                         *mtu = min(*mtu, pmtuprobe ?
1091                                    rt->dst.dev->mtu :
1092                                    dst_mtu(rt->dst.path));
1093                 }
1094                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1095                               + fragheaderlen - sizeof(struct frag_hdr);
1096         }
1097 }
1098
1099 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1100         int offset, int len, int odd, struct sk_buff *skb),
1101         void *from, int length, int transhdrlen,
1102         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1103         struct rt6_info *rt, unsigned int flags, int dontfrag)
1104 {
1105         struct inet_sock *inet = inet_sk(sk);
1106         struct ipv6_pinfo *np = inet6_sk(sk);
1107         struct inet_cork *cork;
1108         struct sk_buff *skb, *skb_prev = NULL;
1109         unsigned int maxfraglen, fragheaderlen, mtu;
1110         int exthdrlen;
1111         int dst_exthdrlen;
1112         int hh_len;
1113         int copy;
1114         int err;
1115         int offset = 0;
1116         __u8 tx_flags = 0;
1117
1118         if (flags&MSG_PROBE)
1119                 return 0;
1120         cork = &inet->cork.base;
1121         if (skb_queue_empty(&sk->sk_write_queue)) {
1122                 /*
1123                  * setup for corking
1124                  */
1125                 if (opt) {
1126                         if (WARN_ON(np->cork.opt))
1127                                 return -EINVAL;
1128
1129                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1130                         if (unlikely(np->cork.opt == NULL))
1131                                 return -ENOBUFS;
1132
1133                         np->cork.opt->tot_len = opt->tot_len;
1134                         np->cork.opt->opt_flen = opt->opt_flen;
1135                         np->cork.opt->opt_nflen = opt->opt_nflen;
1136
1137                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1138                                                             sk->sk_allocation);
1139                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1140                                 return -ENOBUFS;
1141
1142                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1143                                                             sk->sk_allocation);
1144                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1145                                 return -ENOBUFS;
1146
1147                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1148                                                            sk->sk_allocation);
1149                         if (opt->hopopt && !np->cork.opt->hopopt)
1150                                 return -ENOBUFS;
1151
1152                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1153                                                             sk->sk_allocation);
1154                         if (opt->srcrt && !np->cork.opt->srcrt)
1155                                 return -ENOBUFS;
1156
1157                         /* need source address above miyazawa*/
1158                 }
1159                 dst_hold(&rt->dst);
1160                 cork->dst = &rt->dst;
1161                 inet->cork.fl.u.ip6 = *fl6;
1162                 np->cork.hop_limit = hlimit;
1163                 np->cork.tclass = tclass;
1164                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1165                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1166                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1167                 else
1168                         mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1169                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1170                 if (np->frag_size < mtu) {
1171                         if (np->frag_size)
1172                                 mtu = np->frag_size;
1173                 }
1174                 cork->fragsize = mtu;
1175                 if (dst_allfrag(rt->dst.path))
1176                         cork->flags |= IPCORK_ALLFRAG;
1177                 cork->length = 0;
1178                 exthdrlen = (opt ? opt->opt_flen : 0);
1179                 length += exthdrlen;
1180                 transhdrlen += exthdrlen;
1181                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1182         } else {
1183                 rt = (struct rt6_info *)cork->dst;
1184                 fl6 = &inet->cork.fl.u.ip6;
1185                 opt = np->cork.opt;
1186                 transhdrlen = 0;
1187                 exthdrlen = 0;
1188                 dst_exthdrlen = 0;
1189                 mtu = cork->fragsize;
1190         }
1191
1192         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1193
1194         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1195                         (opt ? opt->opt_nflen : 0);
1196         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1197
1198         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1199                 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1200                         ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen);
1201                         return -EMSGSIZE;
1202                 }
1203         }
1204
1205         /* For UDP, check if TX timestamp is enabled */
1206         if (sk->sk_type == SOCK_DGRAM)
1207                 sock_tx_timestamp(sk, &tx_flags);
1208
1209         /*
1210          * Let's try using as much space as possible.
1211          * Use MTU if total length of the message fits into the MTU.
1212          * Otherwise, we need to reserve fragment header and
1213          * fragment alignment (= 8-15 octects, in total).
1214          *
1215          * Note that we may need to "move" the data from the tail of
1216          * of the buffer to the new fragment when we split
1217          * the message.
1218          *
1219          * FIXME: It may be fragmented into multiple chunks
1220          *        at once if non-fragmentable extension headers
1221          *        are too large.
1222          * --yoshfuji
1223          */
1224
1225         if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP ||
1226                                            sk->sk_protocol == IPPROTO_RAW)) {
1227                 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
1228                 return -EMSGSIZE;
1229         }
1230
1231         skb = skb_peek_tail(&sk->sk_write_queue);
1232         cork->length += length;
1233         if (((length > mtu) ||
1234              (skb && skb_is_gso(skb))) &&
1235             (sk->sk_protocol == IPPROTO_UDP) &&
1236             (rt->dst.dev->features & NETIF_F_UFO)) {
1237                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1238                                           hh_len, fragheaderlen,
1239                                           transhdrlen, mtu, flags, rt);
1240                 if (err)
1241                         goto error;
1242                 return 0;
1243         }
1244
1245         if (!skb)
1246                 goto alloc_new_skb;
1247
1248         while (length > 0) {
1249                 /* Check if the remaining data fits into current packet. */
1250                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1251                 if (copy < length)
1252                         copy = maxfraglen - skb->len;
1253
1254                 if (copy <= 0) {
1255                         char *data;
1256                         unsigned int datalen;
1257                         unsigned int fraglen;
1258                         unsigned int fraggap;
1259                         unsigned int alloclen;
1260 alloc_new_skb:
1261                         /* There's no room in the current skb */
1262                         if (skb)
1263                                 fraggap = skb->len - maxfraglen;
1264                         else
1265                                 fraggap = 0;
1266                         /* update mtu and maxfraglen if necessary */
1267                         if (skb == NULL || skb_prev == NULL)
1268                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1269                                                     fragheaderlen, skb, rt,
1270                                                     np->pmtudisc ==
1271                                                     IPV6_PMTUDISC_PROBE);
1272
1273                         skb_prev = skb;
1274
1275                         /*
1276                          * If remaining data exceeds the mtu,
1277                          * we know we need more fragment(s).
1278                          */
1279                         datalen = length + fraggap;
1280
1281                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1282                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1283                         if ((flags & MSG_MORE) &&
1284                             !(rt->dst.dev->features&NETIF_F_SG))
1285                                 alloclen = mtu;
1286                         else
1287                                 alloclen = datalen + fragheaderlen;
1288
1289                         alloclen += dst_exthdrlen;
1290
1291                         if (datalen != length + fraggap) {
1292                                 /*
1293                                  * this is not the last fragment, the trailer
1294                                  * space is regarded as data space.
1295                                  */
1296                                 datalen += rt->dst.trailer_len;
1297                         }
1298
1299                         alloclen += rt->dst.trailer_len;
1300                         fraglen = datalen + fragheaderlen;
1301
1302                         /*
1303                          * We just reserve space for fragment header.
1304                          * Note: this may be overallocation if the message
1305                          * (without MSG_MORE) fits into the MTU.
1306                          */
1307                         alloclen += sizeof(struct frag_hdr);
1308
1309                         if (transhdrlen) {
1310                                 skb = sock_alloc_send_skb(sk,
1311                                                 alloclen + hh_len,
1312                                                 (flags & MSG_DONTWAIT), &err);
1313                         } else {
1314                                 skb = NULL;
1315                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1316                                     2 * sk->sk_sndbuf)
1317                                         skb = sock_wmalloc(sk,
1318                                                            alloclen + hh_len, 1,
1319                                                            sk->sk_allocation);
1320                                 if (unlikely(skb == NULL))
1321                                         err = -ENOBUFS;
1322                                 else {
1323                                         /* Only the initial fragment
1324                                          * is time stamped.
1325                                          */
1326                                         tx_flags = 0;
1327                                 }
1328                         }
1329                         if (skb == NULL)
1330                                 goto error;
1331                         /*
1332                          *      Fill in the control structures
1333                          */
1334                         skb->protocol = htons(ETH_P_IPV6);
1335                         skb->ip_summed = CHECKSUM_NONE;
1336                         skb->csum = 0;
1337                         /* reserve for fragmentation and ipsec header */
1338                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1339                                     dst_exthdrlen);
1340
1341                         if (sk->sk_type == SOCK_DGRAM)
1342                                 skb_shinfo(skb)->tx_flags = tx_flags;
1343
1344                         /*
1345                          *      Find where to start putting bytes
1346                          */
1347                         data = skb_put(skb, fraglen);
1348                         skb_set_network_header(skb, exthdrlen);
1349                         data += fragheaderlen;
1350                         skb->transport_header = (skb->network_header +
1351                                                  fragheaderlen);
1352                         if (fraggap) {
1353                                 skb->csum = skb_copy_and_csum_bits(
1354                                         skb_prev, maxfraglen,
1355                                         data + transhdrlen, fraggap, 0);
1356                                 skb_prev->csum = csum_sub(skb_prev->csum,
1357                                                           skb->csum);
1358                                 data += fraggap;
1359                                 pskb_trim_unique(skb_prev, maxfraglen);
1360                         }
1361                         copy = datalen - transhdrlen - fraggap;
1362
1363                         if (copy < 0) {
1364                                 err = -EINVAL;
1365                                 kfree_skb(skb);
1366                                 goto error;
1367                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1368                                 err = -EFAULT;
1369                                 kfree_skb(skb);
1370                                 goto error;
1371                         }
1372
1373                         offset += copy;
1374                         length -= datalen - fraggap;
1375                         transhdrlen = 0;
1376                         exthdrlen = 0;
1377                         dst_exthdrlen = 0;
1378
1379                         /*
1380                          * Put the packet on the pending queue
1381                          */
1382                         __skb_queue_tail(&sk->sk_write_queue, skb);
1383                         continue;
1384                 }
1385
1386                 if (copy > length)
1387                         copy = length;
1388
1389                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1390                         unsigned int off;
1391
1392                         off = skb->len;
1393                         if (getfrag(from, skb_put(skb, copy),
1394                                                 offset, copy, off, skb) < 0) {
1395                                 __skb_trim(skb, off);
1396                                 err = -EFAULT;
1397                                 goto error;
1398                         }
1399                 } else {
1400                         int i = skb_shinfo(skb)->nr_frags;
1401                         struct page_frag *pfrag = sk_page_frag(sk);
1402
1403                         err = -ENOMEM;
1404                         if (!sk_page_frag_refill(sk, pfrag))
1405                                 goto error;
1406
1407                         if (!skb_can_coalesce(skb, i, pfrag->page,
1408                                               pfrag->offset)) {
1409                                 err = -EMSGSIZE;
1410                                 if (i == MAX_SKB_FRAGS)
1411                                         goto error;
1412
1413                                 __skb_fill_page_desc(skb, i, pfrag->page,
1414                                                      pfrag->offset, 0);
1415                                 skb_shinfo(skb)->nr_frags = ++i;
1416                                 get_page(pfrag->page);
1417                         }
1418                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1419                         if (getfrag(from,
1420                                     page_address(pfrag->page) + pfrag->offset,
1421                                     offset, copy, skb->len, skb) < 0)
1422                                 goto error_efault;
1423
1424                         pfrag->offset += copy;
1425                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1426                         skb->len += copy;
1427                         skb->data_len += copy;
1428                         skb->truesize += copy;
1429                         atomic_add(copy, &sk->sk_wmem_alloc);
1430                 }
1431                 offset += copy;
1432                 length -= copy;
1433         }
1434
1435         return 0;
1436
1437 error_efault:
1438         err = -EFAULT;
1439 error:
1440         cork->length -= length;
1441         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1442         return err;
1443 }
1444 EXPORT_SYMBOL_GPL(ip6_append_data);
1445
1446 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1447 {
1448         if (np->cork.opt) {
1449                 kfree(np->cork.opt->dst0opt);
1450                 kfree(np->cork.opt->dst1opt);
1451                 kfree(np->cork.opt->hopopt);
1452                 kfree(np->cork.opt->srcrt);
1453                 kfree(np->cork.opt);
1454                 np->cork.opt = NULL;
1455         }
1456
1457         if (inet->cork.base.dst) {
1458                 dst_release(inet->cork.base.dst);
1459                 inet->cork.base.dst = NULL;
1460                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1461         }
1462         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1463 }
1464
1465 int ip6_push_pending_frames(struct sock *sk)
1466 {
1467         struct sk_buff *skb, *tmp_skb;
1468         struct sk_buff **tail_skb;
1469         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1470         struct inet_sock *inet = inet_sk(sk);
1471         struct ipv6_pinfo *np = inet6_sk(sk);
1472         struct net *net = sock_net(sk);
1473         struct ipv6hdr *hdr;
1474         struct ipv6_txoptions *opt = np->cork.opt;
1475         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1476         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1477         unsigned char proto = fl6->flowi6_proto;
1478         int err = 0;
1479
1480         if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1481                 goto out;
1482         tail_skb = &(skb_shinfo(skb)->frag_list);
1483
1484         /* move skb->data to ip header from ext header */
1485         if (skb->data < skb_network_header(skb))
1486                 __skb_pull(skb, skb_network_offset(skb));
1487         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1488                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1489                 *tail_skb = tmp_skb;
1490                 tail_skb = &(tmp_skb->next);
1491                 skb->len += tmp_skb->len;
1492                 skb->data_len += tmp_skb->len;
1493                 skb->truesize += tmp_skb->truesize;
1494                 tmp_skb->destructor = NULL;
1495                 tmp_skb->sk = NULL;
1496         }
1497
1498         /* Allow local fragmentation. */
1499         if (np->pmtudisc < IPV6_PMTUDISC_DO)
1500                 skb->local_df = 1;
1501
1502         *final_dst = fl6->daddr;
1503         __skb_pull(skb, skb_network_header_len(skb));
1504         if (opt && opt->opt_flen)
1505                 ipv6_push_frag_opts(skb, opt, &proto);
1506         if (opt && opt->opt_nflen)
1507                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1508
1509         skb_push(skb, sizeof(struct ipv6hdr));
1510         skb_reset_network_header(skb);
1511         hdr = ipv6_hdr(skb);
1512
1513         ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel);
1514         hdr->hop_limit = np->cork.hop_limit;
1515         hdr->nexthdr = proto;
1516         hdr->saddr = fl6->saddr;
1517         hdr->daddr = *final_dst;
1518
1519         skb->priority = sk->sk_priority;
1520         skb->mark = sk->sk_mark;
1521
1522         skb_dst_set(skb, dst_clone(&rt->dst));
1523         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1524         if (proto == IPPROTO_ICMPV6) {
1525                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1526
1527                 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type);
1528                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
1529         }
1530
1531         err = ip6_local_out(skb);
1532         if (err) {
1533                 if (err > 0)
1534                         err = net_xmit_errno(err);
1535                 if (err)
1536                         goto error;
1537         }
1538
1539 out:
1540         ip6_cork_release(inet, np);
1541         return err;
1542 error:
1543         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1544         goto out;
1545 }
1546 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1547
1548 void ip6_flush_pending_frames(struct sock *sk)
1549 {
1550         struct sk_buff *skb;
1551
1552         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1553                 if (skb_dst(skb))
1554                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1555                                       IPSTATS_MIB_OUTDISCARDS);
1556                 kfree_skb(skb);
1557         }
1558
1559         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1560 }
1561 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);