net/ipv6/ip6_output.c

   1 /*
   2  *      IPv6 output functions
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on linux/net/ipv4/ip_output.c
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  *
  15  *      Changes:
  16  *      A.N.Kuznetsov   :       airthmetics in fragmentation.
  17  *                              extension headers are implemented.
  18  *                              route changes now work.
  19  *                              ip6_forward does not confuse sniffers.
  20  *                              etc.
  21  *
  22  *      H. von Brand    :       Added missing #include <linux/string.h>
  23  *      Imran Patel     :       frag id should be in NBO
  24  *      Kazunori MIYAZAWA @USAGI
  25  *                      :       add ip6_append_data and related functions
  26  *                              for datagram xmit
  27  */
  28
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/string.h>
  32 #include <linux/socket.h>
  33 #include <linux/net.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/if_arp.h>
  36 #include <linux/in6.h>
  37 #include <linux/tcp.h>
  38 #include <linux/route.h>
  39 #include <linux/module.h>
  40 #include <linux/slab.h>
  41
  42 #include <linux/netfilter.h>
  43 #include <linux/netfilter_ipv6.h>
  44
  45 #include <net/sock.h>
  46 #include <net/snmp.h>
  47
  48 #include <net/ipv6.h>
  49 #include <net/ndisc.h>
  50 #include <net/protocol.h>
  51 #include <net/ip6_route.h>
  52 #include <net/addrconf.h>
  53 #include <net/rawv6.h>
  54 #include <net/icmp.h>
  55 #include <net/xfrm.h>
  56 #include <net/checksum.h>
  57 #include <linux/mroute6.h>
  58
  59 static int ip6_finish_output2(struct sk_buff *skb)
  60 {
  61         struct dst_entry *dst = skb_dst(skb);
  62         struct net_device *dev = dst->dev;
  63         struct neighbour *neigh;
  64         struct in6_addr *nexthop;
  65         int ret;
  66
  67         skb->protocol = htons(ETH_P_IPV6);
  68         skb->dev = dev;
  69
  70         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
  71                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
  72
  73                 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&
  74                     ((mroute6_socket(dev_net(dev), skb) &&
  75                      !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
  76                      ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
  77                                          &ipv6_hdr(skb)->saddr))) {
  78                         struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  79
  80                         /* Do not check for IFF_ALLMULTI; multicast routing
  81                            is not supported in any case.
  82                          */
  83                         if (newskb)
  84                                 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  85                                         newskb, NULL, newskb->dev,
  86                                         dev_loopback_xmit);
  87
  88                         if (ipv6_hdr(skb)->hop_limit == 0) {
  89                                 IP6_INC_STATS(dev_net(dev), idev,
  90                                               IPSTATS_MIB_OUTDISCARDS);
  91                                 kfree_skb(skb);
  92                                 return 0;
  93                         }
  94                 }
  95
  96                 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST,
  97                                 skb->len);
  98
  99                 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
 100                     IPV6_ADDR_SCOPE_NODELOCAL &&
 101                     !(dev->flags & IFF_LOOPBACK)) {
 102                         kfree_skb(skb);
 103                         return 0;
 104                 }
 105         }
 106
 107         rcu_read_lock_bh();
 108         nexthop = rt6_nexthop((struct rt6_info *)dst);
 109         neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
 110         if (unlikely(!neigh))
 111                 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
 112         if (!IS_ERR(neigh)) {
 113                 ret = dst_neigh_output(dst, neigh, skb);
 114                 rcu_read_unlock_bh();
 115                 return ret;
 116         }
 117         rcu_read_unlock_bh();
 118
 119         IP6_INC_STATS(dev_net(dst->dev),
 120                       ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 121         kfree_skb(skb);
 122         return -EINVAL;
 123 }
 124
 125 static int ip6_finish_output(struct sk_buff *skb)
 126 {
 127         if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
 128             dst_allfrag(skb_dst(skb)) ||
 129             (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 130                 return ip6_fragment(skb, ip6_finish_output2);
 131         else
 132                 return ip6_finish_output2(skb);
 133 }
 134
 135 int ip6_output(struct sock *sk, struct sk_buff *skb)
 136 {
 137         struct net_device *dev = skb_dst(skb)->dev;
 138         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(dev_net(dev), idev,
 141                               IPSTATS_MIB_OUTDISCARDS);
 142                 kfree_skb(skb);
 143                 return 0;
 144         }
 145
 146         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
 147                             ip6_finish_output,
 148                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 149 }
 150
 151 /*
 152  *      xmit an sk_buff (used by TCP, SCTP and DCCP)
 153  */
 154
 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 156              struct ipv6_txoptions *opt, int tclass)
 157 {
 158         struct net *net = sock_net(sk);
 159         struct ipv6_pinfo *np = inet6_sk(sk);
 160         struct in6_addr *first_hop = &fl6->daddr;
 161         struct dst_entry *dst = skb_dst(skb);
 162         struct ipv6hdr *hdr;
 163         u8  proto = fl6->flowi6_proto;
 164         int seg_len = skb->len;
 165         int hlimit = -1;
 166         u32 mtu;
 167
 168         if (opt) {
 169                 unsigned int head_room;
 170
 171                 /* First: exthdrs may take lots of space (~8K for now)
 172                    MAX_HEADER is not enough.
 173                  */
 174                 head_room = opt->opt_nflen + opt->opt_flen;
 175                 seg_len += head_room;
 176                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 177
 178                 if (skb_headroom(skb) < head_room) {
 179                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 180                         if (skb2 == NULL) {
 181                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 182                                               IPSTATS_MIB_OUTDISCARDS);
 183                                 kfree_skb(skb);
 184                                 return -ENOBUFS;
 185                         }
 186                         consume_skb(skb);
 187                         skb = skb2;
 188                         skb_set_owner_w(skb, sk);
 189                 }
 190                 if (opt->opt_flen)
 191                         ipv6_push_frag_opts(skb, opt, &proto);
 192                 if (opt->opt_nflen)
 193                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 194         }
 195
 196         skb_push(skb, sizeof(struct ipv6hdr));
 197         skb_reset_network_header(skb);
 198         hdr = ipv6_hdr(skb);
 199
 200         /*
 201          *      Fill in the IPv6 header
 202          */
 203         if (np)
 204                 hlimit = np->hop_limit;
 205         if (hlimit < 0)
 206                 hlimit = ip6_dst_hoplimit(dst);
 207
 208         ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
 209                                                      np->autoflowlabel));
 210
 211         hdr->payload_len = htons(seg_len);
 212         hdr->nexthdr = proto;
 213         hdr->hop_limit = hlimit;
 214
 215         hdr->saddr = fl6->saddr;
 216         hdr->daddr = *first_hop;
 217
 218         skb->protocol = htons(ETH_P_IPV6);
 219         skb->priority = sk->sk_priority;
 220         skb->mark = sk->sk_mark;
 221
 222         mtu = dst_mtu(dst);
 223         if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 224                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 225                               IPSTATS_MIB_OUT, skb->len);
 226                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 227                                dst->dev, dst_output);
 228         }
 229
 230         skb->dev = dst->dev;
 231         ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
 232         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 233         kfree_skb(skb);
 234         return -EMSGSIZE;
 235 }
 236 EXPORT_SYMBOL(ip6_xmit);
 237
 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 239 {
 240         struct ip6_ra_chain *ra;
 241         struct sock *last = NULL;
 242
 243         read_lock(&ip6_ra_lock);
 244         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 245                 struct sock *sk = ra->sk;
 246                 if (sk && ra->sel == sel &&
 247                     (!sk->sk_bound_dev_if ||
 248                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 249                         if (last) {
 250                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 251                                 if (skb2)
 252                                         rawv6_rcv(last, skb2);
 253                         }
 254                         last = sk;
 255                 }
 256         }
 257
 258         if (last) {
 259                 rawv6_rcv(last, skb);
 260                 read_unlock(&ip6_ra_lock);
 261                 return 1;
 262         }
 263         read_unlock(&ip6_ra_lock);
 264         return 0;
 265 }
 266
 267 static int ip6_forward_proxy_check(struct sk_buff *skb)
 268 {
 269         struct ipv6hdr *hdr = ipv6_hdr(skb);
 270         u8 nexthdr = hdr->nexthdr;
 271         __be16 frag_off;
 272         int offset;
 273
 274         if (ipv6_ext_hdr(nexthdr)) {
 275                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 276                 if (offset < 0)
 277                         return 0;
 278         } else
 279                 offset = sizeof(struct ipv6hdr);
 280
 281         if (nexthdr == IPPROTO_ICMPV6) {
 282                 struct icmp6hdr *icmp6;
 283
 284                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 285                                          offset + 1 - skb->data)))
 286                         return 0;
 287
 288                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 289
 290                 switch (icmp6->icmp6_type) {
 291                 case NDISC_ROUTER_SOLICITATION:
 292                 case NDISC_ROUTER_ADVERTISEMENT:
 293                 case NDISC_NEIGHBOUR_SOLICITATION:
 294                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 295                 case NDISC_REDIRECT:
 296                         /* For reaction involving unicast neighbor discovery
 297                          * message destined to the proxied address, pass it to
 298                          * input function.
 299                          */
 300                         return 1;
 301                 default:
 302                         break;
 303                 }
 304         }
 305
 306         /*
 307          * The proxying router can't forward traffic sent to a link-local
 308          * address, so signal the sender and discard the packet. This
 309          * behavior is clarified by the MIPv6 specification.
 310          */
 311         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 312                 dst_link_failure(skb);
 313                 return -1;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static inline int ip6_forward_finish(struct sk_buff *skb)
 320 {
 321         return dst_output(skb);
 322 }
 323
 324 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 325 {
 326         unsigned int mtu;
 327         struct inet6_dev *idev;
 328
 329         if (dst_metric_locked(dst, RTAX_MTU)) {
 330                 mtu = dst_metric_raw(dst, RTAX_MTU);
 331                 if (mtu)
 332                         return mtu;
 333         }
 334
 335         mtu = IPV6_MIN_MTU;
 336         rcu_read_lock();
 337         idev = __in6_dev_get(dst->dev);
 338         if (idev)
 339                 mtu = idev->cnf.mtu6;
 340         rcu_read_unlock();
 341
 342         return mtu;
 343 }
 344
 345 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 346 {
 347         if (skb->len <= mtu)
 348                 return false;
 349
 350         /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
 351         if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
 352                 return true;
 353
 354         if (skb->ignore_df)
 355                 return false;
 356
 357         if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
 358                 return false;
 359
 360         return true;
 361 }
 362
 363 int ip6_forward(struct sk_buff *skb)
 364 {
 365         struct dst_entry *dst = skb_dst(skb);
 366         struct ipv6hdr *hdr = ipv6_hdr(skb);
 367         struct inet6_skb_parm *opt = IP6CB(skb);
 368         struct net *net = dev_net(dst->dev);
 369         u32 mtu;
 370
 371         if (net->ipv6.devconf_all->forwarding == 0)
 372                 goto error;
 373
 374         if (skb->pkt_type != PACKET_HOST)
 375                 goto drop;
 376
 377         if (skb_warn_if_lro(skb))
 378                 goto drop;
 379
 380         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 381                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 382                                  IPSTATS_MIB_INDISCARDS);
 383                 goto drop;
 384         }
 385
 386         skb_forward_csum(skb);
 387
 388         /*
 389          *      We DO NOT make any processing on
 390          *      RA packets, pushing them to user level AS IS
 391          *      without ane WARRANTY that application will be able
 392          *      to interpret them. The reason is that we
 393          *      cannot make anything clever here.
 394          *
 395          *      We are not end-node, so that if packet contains
 396          *      AH/ESP, we cannot make anything.
 397          *      Defragmentation also would be mistake, RA packets
 398          *      cannot be fragmented, because there is no warranty
 399          *      that different fragments will go along one path. --ANK
 400          */
 401         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 402                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 403                         return 0;
 404         }
 405
 406         /*
 407          *      check and decrement ttl
 408          */
 409         if (hdr->hop_limit <= 1) {
 410                 /* Force OUTPUT device used as source address */
 411                 skb->dev = dst->dev;
 412                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 413                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 414                                  IPSTATS_MIB_INHDRERRORS);
 415
 416                 kfree_skb(skb);
 417                 return -ETIMEDOUT;
 418         }
 419
 420         /* XXX: idev->cnf.proxy_ndp? */
 421         if (net->ipv6.devconf_all->proxy_ndp &&
 422             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 423                 int proxied = ip6_forward_proxy_check(skb);
 424                 if (proxied > 0)
 425                         return ip6_input(skb);
 426                 else if (proxied < 0) {
 427                         IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 428                                          IPSTATS_MIB_INDISCARDS);
 429                         goto drop;
 430                 }
 431         }
 432
 433         if (!xfrm6_route_forward(skb)) {
 434                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 435                                  IPSTATS_MIB_INDISCARDS);
 436                 goto drop;
 437         }
 438         dst = skb_dst(skb);
 439
 440         /* IPv6 specs say nothing about it, but it is clear that we cannot
 441            send redirects to source routed frames.
 442            We don't send redirects to frames decapsulated from IPsec.
 443          */
 444         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 445                 struct in6_addr *target = NULL;
 446                 struct inet_peer *peer;
 447                 struct rt6_info *rt;
 448
 449                 /*
 450                  *      incoming and outgoing devices are the same
 451                  *      send a redirect.
 452                  */
 453
 454                 rt = (struct rt6_info *) dst;
 455                 if (rt->rt6i_flags & RTF_GATEWAY)
 456                         target = &rt->rt6i_gateway;
 457                 else
 458                         target = &hdr->daddr;
 459
 460                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 461
 462                 /* Limit redirects both by destination (here)
 463                    and by source (inside ndisc_send_redirect)
 464                  */
 465                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 466                         ndisc_send_redirect(skb, target);
 467                 if (peer)
 468                         inet_putpeer(peer);
 469         } else {
 470                 int addrtype = ipv6_addr_type(&hdr->saddr);
 471
 472                 /* This check is security critical. */
 473                 if (addrtype == IPV6_ADDR_ANY ||
 474                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 475                         goto error;
 476                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 477                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 478                                     ICMPV6_NOT_NEIGHBOUR, 0);
 479                         goto error;
 480                 }
 481         }
 482
 483         mtu = ip6_dst_mtu_forward(dst);
 484         if (mtu < IPV6_MIN_MTU)
 485                 mtu = IPV6_MIN_MTU;
 486
 487         if (ip6_pkt_too_big(skb, mtu)) {
 488                 /* Again, force OUTPUT device used as source address */
 489                 skb->dev = dst->dev;
 490                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 491                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 492                                  IPSTATS_MIB_INTOOBIGERRORS);
 493                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 494                                  IPSTATS_MIB_FRAGFAILS);
 495                 kfree_skb(skb);
 496                 return -EMSGSIZE;
 497         }
 498
 499         if (skb_cow(skb, dst->dev->hard_header_len)) {
 500                 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
 501                                  IPSTATS_MIB_OUTDISCARDS);
 502                 goto drop;
 503         }
 504
 505         hdr = ipv6_hdr(skb);
 506
 507         /* Mangling hops number delayed to point after skb COW */
 508
 509         hdr->hop_limit--;
 510
 511         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 512         IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 513         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 514                        ip6_forward_finish);
 515
 516 error:
 517         IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 518 drop:
 519         kfree_skb(skb);
 520         return -EINVAL;
 521 }
 522
 523 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 524 {
 525         to->pkt_type = from->pkt_type;
 526         to->priority = from->priority;
 527         to->protocol = from->protocol;
 528         skb_dst_drop(to);
 529         skb_dst_set(to, dst_clone(skb_dst(from)));
 530         to->dev = from->dev;
 531         to->mark = from->mark;
 532
 533 #ifdef CONFIG_NET_SCHED
 534         to->tc_index = from->tc_index;
 535 #endif
 536         nf_copy(to, from);
 537         skb_copy_secmark(to, from);
 538 }
 539
 540 static void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
 541 {
 542         static u32 ip6_idents_hashrnd __read_mostly;
 543         u32 hash, id;
 544
 545         net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));
 546
 547         hash = __ipv6_addr_jhash(&rt->rt6i_dst.addr, ip6_idents_hashrnd);
 548         hash = __ipv6_addr_jhash(&rt->rt6i_src.addr, hash);
 549
 550         id = ip_idents_reserve(hash, 1);
 551         fhdr->identification = htonl(id);
 552 }
 553
 554 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 555 {
 556         struct sk_buff *frag;
 557         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 558         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 559         struct ipv6hdr *tmp_hdr;
 560         struct frag_hdr *fh;
 561         unsigned int mtu, hlen, left, len;
 562         int hroom, troom;
 563         __be32 frag_id = 0;
 564         int ptr, offset = 0, err = 0;
 565         u8 *prevhdr, nexthdr = 0;
 566         struct net *net = dev_net(skb_dst(skb)->dev);
 567
 568         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 569         nexthdr = *prevhdr;
 570
 571         mtu = ip6_skb_dst_mtu(skb);
 572
 573         /* We must not fragment if the socket is set to force MTU discovery
 574          * or if the skb it not generated by a local socket.
 575          */
 576         if (unlikely(!skb->ignore_df && skb->len > mtu) ||
 577                      (IP6CB(skb)->frag_max_size &&
 578                       IP6CB(skb)->frag_max_size > mtu)) {
 579                 if (skb->sk && dst_allfrag(skb_dst(skb)))
 580                         sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 581
 582                 skb->dev = skb_dst(skb)->dev;
 583                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 584                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 585                               IPSTATS_MIB_FRAGFAILS);
 586                 kfree_skb(skb);
 587                 return -EMSGSIZE;
 588         }
 589
 590         if (np && np->frag_size < mtu) {
 591                 if (np->frag_size)
 592                         mtu = np->frag_size;
 593         }
 594         mtu -= hlen + sizeof(struct frag_hdr);
 595
 596         if (skb_has_frag_list(skb)) {
 597                 int first_len = skb_pagelen(skb);
 598                 struct sk_buff *frag2;
 599
 600                 if (first_len - hlen > mtu ||
 601                     ((first_len - hlen) & 7) ||
 602                     skb_cloned(skb))
 603                         goto slow_path;
 604
 605                 skb_walk_frags(skb, frag) {
 606                         /* Correct geometry. */
 607                         if (frag->len > mtu ||
 608                             ((frag->len & 7) && frag->next) ||
 609                             skb_headroom(frag) < hlen)
 610                                 goto slow_path_clean;
 611
 612                         /* Partially cloned skb? */
 613                         if (skb_shared(frag))
 614                                 goto slow_path_clean;
 615
 616                         BUG_ON(frag->sk);
 617                         if (skb->sk) {
 618                                 frag->sk = skb->sk;
 619                                 frag->destructor = sock_wfree;
 620                         }
 621                         skb->truesize -= frag->truesize;
 622                 }
 623
 624                 err = 0;
 625                 offset = 0;
 626                 frag = skb_shinfo(skb)->frag_list;
 627                 skb_frag_list_init(skb);
 628                 /* BUILD HEADER */
 629
 630                 *prevhdr = NEXTHDR_FRAGMENT;
 631                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 632                 if (!tmp_hdr) {
 633                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 634                                       IPSTATS_MIB_FRAGFAILS);
 635                         return -ENOMEM;
 636                 }
 637
 638                 __skb_pull(skb, hlen);
 639                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 640                 __skb_push(skb, hlen);
 641                 skb_reset_network_header(skb);
 642                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 643
 644                 ipv6_select_ident(fh, rt);
 645                 fh->nexthdr = nexthdr;
 646                 fh->reserved = 0;
 647                 fh->frag_off = htons(IP6_MF);
 648                 frag_id = fh->identification;
 649
 650                 first_len = skb_pagelen(skb);
 651                 skb->data_len = first_len - skb_headlen(skb);
 652                 skb->len = first_len;
 653                 ipv6_hdr(skb)->payload_len = htons(first_len -
 654                                                    sizeof(struct ipv6hdr));
 655
 656                 dst_hold(&rt->dst);
 657
 658                 for (;;) {
 659                         /* Prepare header of the next frame,
 660                          * before previous one went down. */
 661                         if (frag) {
 662                                 frag->ip_summed = CHECKSUM_NONE;
 663                                 skb_reset_transport_header(frag);
 664                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 665                                 __skb_push(frag, hlen);
 666                                 skb_reset_network_header(frag);
 667                                 memcpy(skb_network_header(frag), tmp_hdr,
 668                                        hlen);
 669                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 670                                 fh->nexthdr = nexthdr;
 671                                 fh->reserved = 0;
 672                                 fh->frag_off = htons(offset);
 673                                 if (frag->next != NULL)
 674                                         fh->frag_off |= htons(IP6_MF);
 675                                 fh->identification = frag_id;
 676                                 ipv6_hdr(frag)->payload_len =
 677                                                 htons(frag->len -
 678                                                       sizeof(struct ipv6hdr));
 679                                 ip6_copy_metadata(frag, skb);
 680                         }
 681
 682                         err = output(skb);
 683                         if (!err)
 684                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 685                                               IPSTATS_MIB_FRAGCREATES);
 686
 687                         if (err || !frag)
 688                                 break;
 689
 690                         skb = frag;
 691                         frag = skb->next;
 692                         skb->next = NULL;
 693                 }
 694
 695                 kfree(tmp_hdr);
 696
 697                 if (err == 0) {
 698                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 699                                       IPSTATS_MIB_FRAGOKS);
 700                         ip6_rt_put(rt);
 701                         return 0;
 702                 }
 703
 704                 kfree_skb_list(frag);
 705
 706                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 707                               IPSTATS_MIB_FRAGFAILS);
 708                 ip6_rt_put(rt);
 709                 return err;
 710
 711 slow_path_clean:
 712                 skb_walk_frags(skb, frag2) {
 713                         if (frag2 == frag)
 714                                 break;
 715                         frag2->sk = NULL;
 716                         frag2->destructor = NULL;
 717                         skb->truesize += frag2->truesize;
 718                 }
 719         }
 720
 721 slow_path:
 722         if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
 723             skb_checksum_help(skb))
 724                 goto fail;
 725
 726         left = skb->len - hlen;         /* Space per frame */
 727         ptr = hlen;                     /* Where to start from */
 728
 729         /*
 730          *      Fragment the datagram.
 731          */
 732
 733         *prevhdr = NEXTHDR_FRAGMENT;
 734         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 735         troom = rt->dst.dev->needed_tailroom;
 736
 737         /*
 738          *      Keep copying data until we run out.
 739          */
 740         while (left > 0)        {
 741                 len = left;
 742                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 743                 if (len > mtu)
 744                         len = mtu;
 745                 /* IF: we are not sending up to and including the packet end
 746                    then align the next start on an eight byte boundary */
 747                 if (len < left) {
 748                         len &= ~7;
 749                 }
 750
 751                 /* Allocate buffer */
 752                 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 753                                  hroom + troom, GFP_ATOMIC);
 754                 if (!frag) {
 755                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 756                                       IPSTATS_MIB_FRAGFAILS);
 757                         err = -ENOMEM;
 758                         goto fail;
 759                 }
 760
 761                 /*
 762                  *      Set up data on packet
 763                  */
 764
 765                 ip6_copy_metadata(frag, skb);
 766                 skb_reserve(frag, hroom);
 767                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 768                 skb_reset_network_header(frag);
 769                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 770                 frag->transport_header = (frag->network_header + hlen +
 771                                           sizeof(struct frag_hdr));
 772
 773                 /*
 774                  *      Charge the memory for the fragment to any owner
 775                  *      it might possess
 776                  */
 777                 if (skb->sk)
 778                         skb_set_owner_w(frag, skb->sk);
 779
 780                 /*
 781                  *      Copy the packet header into the new buffer.
 782                  */
 783                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 784
 785                 /*
 786                  *      Build fragment header.
 787                  */
 788                 fh->nexthdr = nexthdr;
 789                 fh->reserved = 0;
 790                 if (!frag_id) {
 791                         ipv6_select_ident(fh, rt);
 792                         frag_id = fh->identification;
 793                 } else
 794                         fh->identification = frag_id;
 795
 796                 /*
 797                  *      Copy a block of the IP datagram.
 798                  */
 799                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 800                                      len));
 801                 left -= len;
 802
 803                 fh->frag_off = htons(offset);
 804                 if (left > 0)
 805                         fh->frag_off |= htons(IP6_MF);
 806                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 807                                                     sizeof(struct ipv6hdr));
 808
 809                 ptr += len;
 810                 offset += len;
 811
 812                 /*
 813                  *      Put this fragment into the sending queue.
 814                  */
 815                 err = output(frag);
 816                 if (err)
 817                         goto fail;
 818
 819                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 820                               IPSTATS_MIB_FRAGCREATES);
 821         }
 822         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 823                       IPSTATS_MIB_FRAGOKS);
 824         consume_skb(skb);
 825         return err;
 826
 827 fail:
 828         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 829                       IPSTATS_MIB_FRAGFAILS);
 830         kfree_skb(skb);
 831         return err;
 832 }
 833
 834 static inline int ip6_rt_check(const struct rt6key *rt_key,
 835                                const struct in6_addr *fl_addr,
 836                                const struct in6_addr *addr_cache)
 837 {
 838         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 839                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
 840 }
 841
 842 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 843                                           struct dst_entry *dst,
 844                                           const struct flowi6 *fl6)
 845 {
 846         struct ipv6_pinfo *np = inet6_sk(sk);
 847         struct rt6_info *rt;
 848
 849         if (!dst)
 850                 goto out;
 851
 852         if (dst->ops->family != AF_INET6) {
 853                 dst_release(dst);
 854                 return NULL;
 855         }
 856
 857         rt = (struct rt6_info *)dst;
 858         /* Yes, checking route validity in not connected
 859          * case is not very simple. Take into account,
 860          * that we do not support routing by source, TOS,
 861          * and MSG_DONTROUTE            --ANK (980726)
 862          *
 863          * 1. ip6_rt_check(): If route was host route,
 864          *    check that cached destination is current.
 865          *    If it is network route, we still may
 866          *    check its validity using saved pointer
 867          *    to the last used address: daddr_cache.
 868          *    We do not want to save whole address now,
 869          *    (because main consumer of this service
 870          *    is tcp, which has not this problem),
 871          *    so that the last trick works only on connected
 872          *    sockets.
 873          * 2. oif also should be the same.
 874          */
 875         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 876 #ifdef CONFIG_IPV6_SUBTREES
 877             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 878 #endif
 879             (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
 880                 dst_release(dst);
 881                 dst = NULL;
 882         }
 883
 884 out:
 885         return dst;
 886 }
 887
 888 static int ip6_dst_lookup_tail(struct sock *sk,
 889                                struct dst_entry **dst, struct flowi6 *fl6)
 890 {
 891         struct net *net = sock_net(sk);
 892 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 893         struct neighbour *n;
 894         struct rt6_info *rt;
 895 #endif
 896         int err;
 897
 898         if (*dst == NULL)
 899                 *dst = ip6_route_output(net, sk, fl6);
 900
 901         err = (*dst)->error;
 902         if (err)
 903                 goto out_err_release;
 904
 905         if (ipv6_addr_any(&fl6->saddr)) {
 906                 struct rt6_info *rt = (struct rt6_info *) *dst;
 907                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 908                                           sk ? inet6_sk(sk)->srcprefs : 0,
 909                                           &fl6->saddr);
 910                 if (err)
 911                         goto out_err_release;
 912         }
 913
 914 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 915         /*
 916          * Here if the dst entry we've looked up
 917          * has a neighbour entry that is in the INCOMPLETE
 918          * state and the src address from the flow is
 919          * marked as OPTIMISTIC, we release the found
 920          * dst entry and replace it instead with the
 921          * dst entry of the nexthop router
 922          */
 923         rt = (struct rt6_info *) *dst;
 924         rcu_read_lock_bh();
 925         n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
 926         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 927         rcu_read_unlock_bh();
 928
 929         if (err) {
 930                 struct inet6_ifaddr *ifp;
 931                 struct flowi6 fl_gw6;
 932                 int redirect;
 933
 934                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 935                                       (*dst)->dev, 1);
 936
 937                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 938                 if (ifp)
 939                         in6_ifa_put(ifp);
 940
 941                 if (redirect) {
 942                         /*
 943                          * We need to get the dst entry for the
 944                          * default router instead
 945                          */
 946                         dst_release(*dst);
 947                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 948                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 949                         *dst = ip6_route_output(net, sk, &fl_gw6);
 950                         err = (*dst)->error;
 951                         if (err)
 952                                 goto out_err_release;
 953                 }
 954         }
 955 #endif
 956
 957         return 0;
 958
 959 out_err_release:
 960         if (err == -ENETUNREACH)
 961                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
 962         dst_release(*dst);
 963         *dst = NULL;
 964         return err;
 965 }
 966
 967 /**
 968  *      ip6_dst_lookup - perform route lookup on flow
 969  *      @sk: socket which provides route info
 970  *      @dst: pointer to dst_entry * for result
 971  *      @fl6: flow to lookup
 972  *
 973  *      This function performs a route lookup on the given flow.
 974  *
 975  *      It returns zero on success, or a standard errno code on error.
 976  */
 977 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
 978 {
 979         *dst = NULL;
 980         return ip6_dst_lookup_tail(sk, dst, fl6);
 981 }
 982 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 983
 984 /**
 985  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
 986  *      @sk: socket which provides route info
 987  *      @fl6: flow to lookup
 988  *      @final_dst: final destination address for ipsec lookup
 989  *
 990  *      This function performs a route lookup on the given flow.
 991  *
 992  *      It returns a valid dst pointer on success, or a pointer encoded
 993  *      error code.
 994  */
 995 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 996                                       const struct in6_addr *final_dst)
 997 {
 998         struct dst_entry *dst = NULL;
 999         int err;
1000
1001         err = ip6_dst_lookup_tail(sk, &dst, fl6);
1002         if (err)
1003                 return ERR_PTR(err);
1004         if (final_dst)
1005                 fl6->daddr = *final_dst;
1006
1007         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1008 }
1009 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1010
1011 /**
1012  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1013  *      @sk: socket which provides the dst cache and route info
1014  *      @fl6: flow to lookup
1015  *      @final_dst: final destination address for ipsec lookup
1016  *
1017  *      This function performs a route lookup on the given flow with the
1018  *      possibility of using the cached route in the socket if it is valid.
1019  *      It will take the socket dst lock when operating on the dst cache.
1020  *      As a result, this function can only be used in process context.
1021  *
1022  *      It returns a valid dst pointer on success, or a pointer encoded
1023  *      error code.
1024  */
1025 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1026                                          const struct in6_addr *final_dst)
1027 {
1028         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1029         int err;
1030
1031         dst = ip6_sk_dst_check(sk, dst, fl6);
1032
1033         err = ip6_dst_lookup_tail(sk, &dst, fl6);
1034         if (err)
1035                 return ERR_PTR(err);
1036         if (final_dst)
1037                 fl6->daddr = *final_dst;
1038
1039         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1040 }
1041 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1042
1043 static inline int ip6_ufo_append_data(struct sock *sk,
1044                         int getfrag(void *from, char *to, int offset, int len,
1045                         int odd, struct sk_buff *skb),
1046                         void *from, int length, int hh_len, int fragheaderlen,
1047                         int transhdrlen, int mtu, unsigned int flags,
1048                         struct rt6_info *rt)
1049
1050 {
1051         struct sk_buff *skb;
1052         struct frag_hdr fhdr;
1053         int err;
1054
1055         /* There is support for UDP large send offload by network
1056          * device, so create one single skb packet containing complete
1057          * udp datagram
1058          */
1059         skb = skb_peek_tail(&sk->sk_write_queue);
1060         if (skb == NULL) {
1061                 skb = sock_alloc_send_skb(sk,
1062                         hh_len + fragheaderlen + transhdrlen + 20,
1063                         (flags & MSG_DONTWAIT), &err);
1064                 if (skb == NULL)
1065                         return err;
1066
1067                 /* reserve space for Hardware header */
1068                 skb_reserve(skb, hh_len);
1069
1070                 /* create space for UDP/IP header */
1071                 skb_put(skb, fragheaderlen + transhdrlen);
1072
1073                 /* initialize network header pointer */
1074                 skb_reset_network_header(skb);
1075
1076                 /* initialize protocol header pointer */
1077                 skb->transport_header = skb->network_header + fragheaderlen;
1078
1079                 skb->protocol = htons(ETH_P_IPV6);
1080                 skb->csum = 0;
1081
1082                 __skb_queue_tail(&sk->sk_write_queue, skb);
1083         } else if (skb_is_gso(skb)) {
1084                 goto append;
1085         }
1086
1087         skb->ip_summed = CHECKSUM_PARTIAL;
1088         /* Specify the length of each IPv6 datagram fragment.
1089          * It has to be a multiple of 8.
1090          */
1091         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1092                                      sizeof(struct frag_hdr)) & ~7;
1093         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1094         ipv6_select_ident(&fhdr, rt);
1095         skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1096
1097 append:
1098         return skb_append_datato_frags(sk, skb, getfrag, from,
1099                                        (length - transhdrlen));
1100 }
1101
1102 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1103                                                gfp_t gfp)
1104 {
1105         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1106 }
1107
1108 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1109                                                 gfp_t gfp)
1110 {
1111         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1112 }
1113
1114 static void ip6_append_data_mtu(unsigned int *mtu,
1115                                 int *maxfraglen,
1116                                 unsigned int fragheaderlen,
1117                                 struct sk_buff *skb,
1118                                 struct rt6_info *rt,
1119                                 unsigned int orig_mtu)
1120 {
1121         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1122                 if (skb == NULL) {
1123                         /* first fragment, reserve header_len */
1124                         *mtu = orig_mtu - rt->dst.header_len;
1125
1126                 } else {
1127                         /*
1128                          * this fragment is not first, the headers
1129                          * space is regarded as data space.
1130                          */
1131                         *mtu = orig_mtu;
1132                 }
1133                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1134                               + fragheaderlen - sizeof(struct frag_hdr);
1135         }
1136 }
1137
1138 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1139         int offset, int len, int odd, struct sk_buff *skb),
1140         void *from, int length, int transhdrlen,
1141         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1142         struct rt6_info *rt, unsigned int flags, int dontfrag)
1143 {
1144         struct inet_sock *inet = inet_sk(sk);
1145         struct ipv6_pinfo *np = inet6_sk(sk);
1146         struct inet_cork *cork;
1147         struct sk_buff *skb, *skb_prev = NULL;
1148         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1149         int exthdrlen;
1150         int dst_exthdrlen;
1151         int hh_len;
1152         int copy;
1153         int err;
1154         int offset = 0;
1155         __u8 tx_flags = 0;
1156         u32 tskey = 0;
1157
1158         if (flags&MSG_PROBE)
1159                 return 0;
1160         cork = &inet->cork.base;
1161         if (skb_queue_empty(&sk->sk_write_queue)) {
1162                 /*
1163                  * setup for corking
1164                  */
1165                 if (opt) {
1166                         if (WARN_ON(np->cork.opt))
1167                                 return -EINVAL;
1168
1169                         np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1170                         if (unlikely(np->cork.opt == NULL))
1171                                 return -ENOBUFS;
1172
1173                         np->cork.opt->tot_len = opt->tot_len;
1174                         np->cork.opt->opt_flen = opt->opt_flen;
1175                         np->cork.opt->opt_nflen = opt->opt_nflen;
1176
1177                         np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1178                                                             sk->sk_allocation);
1179                         if (opt->dst0opt && !np->cork.opt->dst0opt)
1180                                 return -ENOBUFS;
1181
1182                         np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1183                                                             sk->sk_allocation);
1184                         if (opt->dst1opt && !np->cork.opt->dst1opt)
1185                                 return -ENOBUFS;
1186
1187                         np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1188                                                            sk->sk_allocation);
1189                         if (opt->hopopt && !np->cork.opt->hopopt)
1190                                 return -ENOBUFS;
1191
1192                         np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1193                                                             sk->sk_allocation);
1194                         if (opt->srcrt && !np->cork.opt->srcrt)
1195                                 return -ENOBUFS;
1196
1197                         /* need source address above miyazawa*/
1198                 }
1199                 dst_hold(&rt->dst);
1200                 cork->dst = &rt->dst;
1201                 inet->cork.fl.u.ip6 = *fl6;
1202                 np->cork.hop_limit = hlimit;
1203                 np->cork.tclass = tclass;
1204                 if (rt->dst.flags & DST_XFRM_TUNNEL)
1205                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1206                               rt->dst.dev->mtu : dst_mtu(&rt->dst);
1207                 else
1208                         mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1209                               rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1210                 if (np->frag_size < mtu) {
1211                         if (np->frag_size)
1212                                 mtu = np->frag_size;
1213                 }
1214                 cork->fragsize = mtu;
1215                 if (dst_allfrag(rt->dst.path))
1216                         cork->flags |= IPCORK_ALLFRAG;
1217                 cork->length = 0;
1218                 exthdrlen = (opt ? opt->opt_flen : 0);
1219                 length += exthdrlen;
1220                 transhdrlen += exthdrlen;
1221                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1222         } else {
1223                 rt = (struct rt6_info *)cork->dst;
1224                 fl6 = &inet->cork.fl.u.ip6;
1225                 opt = np->cork.opt;
1226                 transhdrlen = 0;
1227                 exthdrlen = 0;
1228                 dst_exthdrlen = 0;
1229                 mtu = cork->fragsize;
1230         }
1231         orig_mtu = mtu;
1232
1233         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1234
1235         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1236                         (opt ? opt->opt_nflen : 0);
1237         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1238                      sizeof(struct frag_hdr);
1239
1240         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1241                 unsigned int maxnonfragsize, headersize;
1242
1243                 headersize = sizeof(struct ipv6hdr) +
1244                              (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1245                              (dst_allfrag(&rt->dst) ?
1246                               sizeof(struct frag_hdr) : 0) +
1247                              rt->rt6i_nfheader_len;
1248
1249                 if (ip6_sk_ignore_df(sk))
1250                         maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1251                 else
1252                         maxnonfragsize = mtu;
1253
1254                 /* dontfrag active */
1255                 if ((cork->length + length > mtu - headersize) && dontfrag &&
1256                     (sk->sk_protocol == IPPROTO_UDP ||
1257                      sk->sk_protocol == IPPROTO_RAW)) {
1258                         ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1259                                                    sizeof(struct ipv6hdr));
1260                         goto emsgsize;
1261                 }
1262
1263                 if (cork->length + length > maxnonfragsize - headersize) {
1264 emsgsize:
1265                         ipv6_local_error(sk, EMSGSIZE, fl6,
1266                                          mtu - headersize +
1267                                          sizeof(struct ipv6hdr));
1268                         return -EMSGSIZE;
1269                 }
1270         }
1271
1272         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1273                 sock_tx_timestamp(sk, &tx_flags);
1274                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1275                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1276                         tskey = sk->sk_tskey++;
1277         }
1278
1279         /*
1280          * Let's try using as much space as possible.
1281          * Use MTU if total length of the message fits into the MTU.
1282          * Otherwise, we need to reserve fragment header and
1283          * fragment alignment (= 8-15 octects, in total).
1284          *
1285          * Note that we may need to "move" the data from the tail of
1286          * of the buffer to the new fragment when we split
1287          * the message.
1288          *
1289          * FIXME: It may be fragmented into multiple chunks
1290          *        at once if non-fragmentable extension headers
1291          *        are too large.
1292          * --yoshfuji
1293          */
1294
1295         skb = skb_peek_tail(&sk->sk_write_queue);
1296         cork->length += length;
1297         if (((length > mtu) ||
1298              (skb && skb_is_gso(skb))) &&
1299             (sk->sk_protocol == IPPROTO_UDP) &&
1300             (rt->dst.dev->features & NETIF_F_UFO)) {
1301                 err = ip6_ufo_append_data(sk, getfrag, from, length,
1302                                           hh_len, fragheaderlen,
1303                                           transhdrlen, mtu, flags, rt);
1304                 if (err)
1305                         goto error;
1306                 return 0;
1307         }
1308
1309         if (!skb)
1310                 goto alloc_new_skb;
1311
1312         while (length > 0) {
1313                 /* Check if the remaining data fits into current packet. */
1314                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1315                 if (copy < length)
1316                         copy = maxfraglen - skb->len;
1317
1318                 if (copy <= 0) {
1319                         char *data;
1320                         unsigned int datalen;
1321                         unsigned int fraglen;
1322                         unsigned int fraggap;
1323                         unsigned int alloclen;
1324 alloc_new_skb:
1325                         /* There's no room in the current skb */
1326                         if (skb)
1327                                 fraggap = skb->len - maxfraglen;
1328                         else
1329                                 fraggap = 0;
1330                         /* update mtu and maxfraglen if necessary */
1331                         if (skb == NULL || skb_prev == NULL)
1332                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1333                                                     fragheaderlen, skb, rt,
1334                                                     orig_mtu);
1335
1336                         skb_prev = skb;
1337
1338                         /*
1339                          * If remaining data exceeds the mtu,
1340                          * we know we need more fragment(s).
1341                          */
1342                         datalen = length + fraggap;
1343
1344                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1345                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1346                         if ((flags & MSG_MORE) &&
1347                             !(rt->dst.dev->features&NETIF_F_SG))
1348                                 alloclen = mtu;
1349                         else
1350                                 alloclen = datalen + fragheaderlen;
1351
1352                         alloclen += dst_exthdrlen;
1353
1354                         if (datalen != length + fraggap) {
1355                                 /*
1356                                  * this is not the last fragment, the trailer
1357                                  * space is regarded as data space.
1358                                  */
1359                                 datalen += rt->dst.trailer_len;
1360                         }
1361
1362                         alloclen += rt->dst.trailer_len;
1363                         fraglen = datalen + fragheaderlen;
1364
1365                         /*
1366                          * We just reserve space for fragment header.
1367                          * Note: this may be overallocation if the message
1368                          * (without MSG_MORE) fits into the MTU.
1369                          */
1370                         alloclen += sizeof(struct frag_hdr);
1371
1372                         if (transhdrlen) {
1373                                 skb = sock_alloc_send_skb(sk,
1374                                                 alloclen + hh_len,
1375                                                 (flags & MSG_DONTWAIT), &err);
1376                         } else {
1377                                 skb = NULL;
1378                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1379                                     2 * sk->sk_sndbuf)
1380                                         skb = sock_wmalloc(sk,
1381                                                            alloclen + hh_len, 1,
1382                                                            sk->sk_allocation);
1383                                 if (unlikely(skb == NULL))
1384                                         err = -ENOBUFS;
1385                         }
1386                         if (skb == NULL)
1387                                 goto error;
1388                         /*
1389                          *      Fill in the control structures
1390                          */
1391                         skb->protocol = htons(ETH_P_IPV6);
1392                         skb->ip_summed = CHECKSUM_NONE;
1393                         skb->csum = 0;
1394                         /* reserve for fragmentation and ipsec header */
1395                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1396                                     dst_exthdrlen);
1397
1398                         /* Only the initial fragment is time stamped */
1399                         skb_shinfo(skb)->tx_flags = tx_flags;
1400                         tx_flags = 0;
1401                         skb_shinfo(skb)->tskey = tskey;
1402                         tskey = 0;
1403
1404                         /*
1405                          *      Find where to start putting bytes
1406                          */
1407                         data = skb_put(skb, fraglen);
1408                         skb_set_network_header(skb, exthdrlen);
1409                         data += fragheaderlen;
1410                         skb->transport_header = (skb->network_header +
1411                                                  fragheaderlen);
1412                         if (fraggap) {
1413                                 skb->csum = skb_copy_and_csum_bits(
1414                                         skb_prev, maxfraglen,
1415                                         data + transhdrlen, fraggap, 0);
1416                                 skb_prev->csum = csum_sub(skb_prev->csum,
1417                                                           skb->csum);
1418                                 data += fraggap;
1419                                 pskb_trim_unique(skb_prev, maxfraglen);
1420                         }
1421                         copy = datalen - transhdrlen - fraggap;
1422
1423                         if (copy < 0) {
1424                                 err = -EINVAL;
1425                                 kfree_skb(skb);
1426                                 goto error;
1427                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1428                                 err = -EFAULT;
1429                                 kfree_skb(skb);
1430                                 goto error;
1431                         }
1432
1433                         offset += copy;
1434                         length -= datalen - fraggap;
1435                         transhdrlen = 0;
1436                         exthdrlen = 0;
1437                         dst_exthdrlen = 0;
1438
1439                         /*
1440                          * Put the packet on the pending queue
1441                          */
1442                         __skb_queue_tail(&sk->sk_write_queue, skb);
1443                         continue;
1444                 }
1445
1446                 if (copy > length)
1447                         copy = length;
1448
1449                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1450                         unsigned int off;
1451
1452                         off = skb->len;
1453                         if (getfrag(from, skb_put(skb, copy),
1454                                                 offset, copy, off, skb) < 0) {
1455                                 __skb_trim(skb, off);
1456                                 err = -EFAULT;
1457                                 goto error;
1458                         }
1459                 } else {
1460                         int i = skb_shinfo(skb)->nr_frags;
1461                         struct page_frag *pfrag = sk_page_frag(sk);
1462
1463                         err = -ENOMEM;
1464                         if (!sk_page_frag_refill(sk, pfrag))
1465                                 goto error;
1466
1467                         if (!skb_can_coalesce(skb, i, pfrag->page,
1468                                               pfrag->offset)) {
1469                                 err = -EMSGSIZE;
1470                                 if (i == MAX_SKB_FRAGS)
1471                                         goto error;
1472
1473                                 __skb_fill_page_desc(skb, i, pfrag->page,
1474                                                      pfrag->offset, 0);
1475                                 skb_shinfo(skb)->nr_frags = ++i;
1476                                 get_page(pfrag->page);
1477                         }
1478                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1479                         if (getfrag(from,
1480                                     page_address(pfrag->page) + pfrag->offset,
1481                                     offset, copy, skb->len, skb) < 0)
1482                                 goto error_efault;
1483
1484                         pfrag->offset += copy;
1485                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1486                         skb->len += copy;
1487                         skb->data_len += copy;
1488                         skb->truesize += copy;
1489                         atomic_add(copy, &sk->sk_wmem_alloc);
1490                 }
1491                 offset += copy;
1492                 length -= copy;
1493         }
1494
1495         return 0;
1496
1497 error_efault:
1498         err = -EFAULT;
1499 error:
1500         cork->length -= length;
1501         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1502         return err;
1503 }
1504 EXPORT_SYMBOL_GPL(ip6_append_data);
1505
1506 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1507 {
1508         if (np->cork.opt) {
1509                 kfree(np->cork.opt->dst0opt);
1510                 kfree(np->cork.opt->dst1opt);
1511                 kfree(np->cork.opt->hopopt);
1512                 kfree(np->cork.opt->srcrt);
1513                 kfree(np->cork.opt);
1514                 np->cork.opt = NULL;
1515         }
1516
1517         if (inet->cork.base.dst) {
1518                 dst_release(inet->cork.base.dst);
1519                 inet->cork.base.dst = NULL;
1520                 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1521         }
1522         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1523 }
1524
1525 int ip6_push_pending_frames(struct sock *sk)
1526 {
1527         struct sk_buff *skb, *tmp_skb;
1528         struct sk_buff **tail_skb;
1529         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1530         struct inet_sock *inet = inet_sk(sk);
1531         struct ipv6_pinfo *np = inet6_sk(sk);
1532         struct net *net = sock_net(sk);
1533         struct ipv6hdr *hdr;
1534         struct ipv6_txoptions *opt = np->cork.opt;
1535         struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1536         struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1537         unsigned char proto = fl6->flowi6_proto;
1538         int err = 0;
1539
1540         skb = __skb_dequeue(&sk->sk_write_queue);
1541         if (skb == NULL)
1542                 goto out;
1543         tail_skb = &(skb_shinfo(skb)->frag_list);
1544
1545         /* move skb->data to ip header from ext header */
1546         if (skb->data < skb_network_header(skb))
1547                 __skb_pull(skb, skb_network_offset(skb));
1548         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1549                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1550                 *tail_skb = tmp_skb;
1551                 tail_skb = &(tmp_skb->next);
1552                 skb->len += tmp_skb->len;
1553                 skb->data_len += tmp_skb->len;
1554                 skb->truesize += tmp_skb->truesize;
1555                 tmp_skb->destructor = NULL;
1556                 tmp_skb->sk = NULL;
1557         }
1558
1559         /* Allow local fragmentation. */
1560         skb->ignore_df = ip6_sk_ignore_df(sk);
1561
1562         *final_dst = fl6->daddr;
1563         __skb_pull(skb, skb_network_header_len(skb));
1564         if (opt && opt->opt_flen)
1565                 ipv6_push_frag_opts(skb, opt, &proto);
1566         if (opt && opt->opt_nflen)
1567                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1568
1569         skb_push(skb, sizeof(struct ipv6hdr));
1570         skb_reset_network_header(skb);
1571         hdr = ipv6_hdr(skb);
1572
1573         ip6_flow_hdr(hdr, np->cork.tclass,
1574                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1575                                         np->autoflowlabel));
1576         hdr->hop_limit = np->cork.hop_limit;
1577         hdr->nexthdr = proto;
1578         hdr->saddr = fl6->saddr;
1579         hdr->daddr = *final_dst;
1580
1581         skb->priority = sk->sk_priority;
1582         skb->mark = sk->sk_mark;
1583
1584         skb_dst_set(skb, dst_clone(&rt->dst));
1585         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1586         if (proto == IPPROTO_ICMPV6) {
1587                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1588
1589                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1590                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1591         }
1592
1593         err = ip6_local_out(skb);
1594         if (err) {
1595                 if (err > 0)
1596                         err = net_xmit_errno(err);
1597                 if (err)
1598                         goto error;
1599         }
1600
1601 out:
1602         ip6_cork_release(inet, np);
1603         return err;
1604 error:
1605         IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1606         goto out;
1607 }
1608 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1609
1610 void ip6_flush_pending_frames(struct sock *sk)
1611 {
1612         struct sk_buff *skb;
1613
1614         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1615                 if (skb_dst(skb))
1616                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1617                                       IPSTATS_MIB_OUTDISCARDS);
1618                 kfree_skb(skb);
1619         }
1620
1621         ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1622 }
1623 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);