net/ipv6/ip6_output.c

   1 /*
   2  *      IPv6 output functions
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on linux/net/ipv4/ip_output.c
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  *
  15  *      Changes:
  16  *      A.N.Kuznetsov   :       airthmetics in fragmentation.
  17  *                              extension headers are implemented.
  18  *                              route changes now work.
  19  *                              ip6_forward does not confuse sniffers.
  20  *                              etc.
  21  *
  22  *      H. von Brand    :       Added missing #include <linux/string.h>
  23  *      Imran Patel     :       frag id should be in NBO
  24  *      Kazunori MIYAZAWA @USAGI
  25  *                      :       add ip6_append_data and related functions
  26  *                              for datagram xmit
  27  */
  28
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/string.h>
  32 #include <linux/socket.h>
  33 #include <linux/net.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/if_arp.h>
  36 #include <linux/in6.h>
  37 #include <linux/tcp.h>
  38 #include <linux/route.h>
  39 #include <linux/module.h>
  40 #include <linux/slab.h>
  41
  42 #include <linux/netfilter.h>
  43 #include <linux/netfilter_ipv6.h>
  44
  45 #include <net/sock.h>
  46 #include <net/snmp.h>
  47
  48 #include <net/ipv6.h>
  49 #include <net/ndisc.h>
  50 #include <net/protocol.h>
  51 #include <net/ip6_route.h>
  52 #include <net/addrconf.h>
  53 #include <net/rawv6.h>
  54 #include <net/icmp.h>
  55 #include <net/xfrm.h>
  56 #include <net/checksum.h>
  57 #include <linux/mroute6.h>
  58 #include <net/l3mdev.h>
  59
  60 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
  61 {
  62         struct dst_entry *dst = skb_dst(skb);
  63         struct net_device *dev = dst->dev;
  64         struct neighbour *neigh;
  65         struct in6_addr *nexthop;
  66         int ret;
  67
  68         skb->protocol = htons(ETH_P_IPV6);
  69         skb->dev = dev;
  70
  71         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
  72                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
  73
  74                 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
  75                     ((mroute6_socket(net, skb) &&
  76                      !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
  77                      ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
  78                                          &ipv6_hdr(skb)->saddr))) {
  79                         struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  80
  81                         /* Do not check for IFF_ALLMULTI; multicast routing
  82                            is not supported in any case.
  83                          */
  84                         if (newskb)
  85                                 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  86                                         net, sk, newskb, NULL, newskb->dev,
  87                                         dev_loopback_xmit);
  88
  89                         if (ipv6_hdr(skb)->hop_limit == 0) {
  90                                 IP6_INC_STATS(net, idev,
  91                                               IPSTATS_MIB_OUTDISCARDS);
  92                                 kfree_skb(skb);
  93                                 return 0;
  94                         }
  95                 }
  96
  97                 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
  98
  99                 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
 100                     IPV6_ADDR_SCOPE_NODELOCAL &&
 101                     !(dev->flags & IFF_LOOPBACK)) {
 102                         kfree_skb(skb);
 103                         return 0;
 104                 }
 105         }
 106
 107         rcu_read_lock_bh();
 108         nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
 109         neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
 110         if (unlikely(!neigh))
 111                 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
 112         if (!IS_ERR(neigh)) {
 113                 ret = dst_neigh_output(dst, neigh, skb);
 114                 rcu_read_unlock_bh();
 115                 return ret;
 116         }
 117         rcu_read_unlock_bh();
 118
 119         IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 120         kfree_skb(skb);
 121         return -EINVAL;
 122 }
 123
 124 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 125 {
 126         if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
 127             dst_allfrag(skb_dst(skb)) ||
 128             (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 129                 return ip6_fragment(net, sk, skb, ip6_finish_output2);
 130         else
 131                 return ip6_finish_output2(net, sk, skb);
 132 }
 133
 134 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 135 {
 136         struct net_device *dev = skb_dst(skb)->dev;
 137         struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
 138
 139         if (unlikely(idev->cnf.disable_ipv6)) {
 140                 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
 141                 kfree_skb(skb);
 142                 return 0;
 143         }
 144
 145         return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
 146                             net, sk, skb, NULL, dev,
 147                             ip6_finish_output,
 148                             !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 149 }
 150
 151 /*
 152  * xmit an sk_buff (used by TCP, SCTP and DCCP)
 153  * Note : socket lock is not held for SYNACK packets, but might be modified
 154  * by calls to skb_set_owner_w() and ipv6_local_error(),
 155  * which are using proper atomic operations or spinlocks.
 156  */
 157 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 158              struct ipv6_txoptions *opt, int tclass)
 159 {
 160         struct net *net = sock_net(sk);
 161         const struct ipv6_pinfo *np = inet6_sk(sk);
 162         struct in6_addr *first_hop = &fl6->daddr;
 163         struct dst_entry *dst = skb_dst(skb);
 164         struct ipv6hdr *hdr;
 165         u8  proto = fl6->flowi6_proto;
 166         int seg_len = skb->len;
 167         int hlimit = -1;
 168         u32 mtu;
 169
 170         if (opt) {
 171                 unsigned int head_room;
 172
 173                 /* First: exthdrs may take lots of space (~8K for now)
 174                    MAX_HEADER is not enough.
 175                  */
 176                 head_room = opt->opt_nflen + opt->opt_flen;
 177                 seg_len += head_room;
 178                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 179
 180                 if (skb_headroom(skb) < head_room) {
 181                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 182                         if (!skb2) {
 183                                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 184                                               IPSTATS_MIB_OUTDISCARDS);
 185                                 kfree_skb(skb);
 186                                 return -ENOBUFS;
 187                         }
 188                         consume_skb(skb);
 189                         skb = skb2;
 190                         /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically,
 191                          * it is safe to call in our context (socket lock not held)
 192                          */
 193                         skb_set_owner_w(skb, (struct sock *)sk);
 194                 }
 195                 if (opt->opt_flen)
 196                         ipv6_push_frag_opts(skb, opt, &proto);
 197                 if (opt->opt_nflen)
 198                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 199         }
 200
 201         skb_push(skb, sizeof(struct ipv6hdr));
 202         skb_reset_network_header(skb);
 203         hdr = ipv6_hdr(skb);
 204
 205         /*
 206          *      Fill in the IPv6 header
 207          */
 208         if (np)
 209                 hlimit = np->hop_limit;
 210         if (hlimit < 0)
 211                 hlimit = ip6_dst_hoplimit(dst);
 212
 213         ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
 214                                                      np->autoflowlabel, fl6));
 215
 216         hdr->payload_len = htons(seg_len);
 217         hdr->nexthdr = proto;
 218         hdr->hop_limit = hlimit;
 219
 220         hdr->saddr = fl6->saddr;
 221         hdr->daddr = *first_hop;
 222
 223         skb->protocol = htons(ETH_P_IPV6);
 224         skb->priority = sk->sk_priority;
 225         skb->mark = sk->sk_mark;
 226
 227         mtu = dst_mtu(dst);
 228         if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 229                 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 230                               IPSTATS_MIB_OUT, skb->len);
 231                 /* hooks should never assume socket lock is held.
 232                  * we promote our socket to non const
 233                  */
 234                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 235                                net, (struct sock *)sk, skb, NULL, dst->dev,
 236                                dst_output);
 237         }
 238
 239         skb->dev = dst->dev;
 240         /* ipv6_local_error() does not require socket lock,
 241          * we promote our socket to non const
 242          */
 243         ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
 244
 245         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
 246         kfree_skb(skb);
 247         return -EMSGSIZE;
 248 }
 249 EXPORT_SYMBOL(ip6_xmit);
 250
 251 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 252 {
 253         struct ip6_ra_chain *ra;
 254         struct sock *last = NULL;
 255
 256         read_lock(&ip6_ra_lock);
 257         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 258                 struct sock *sk = ra->sk;
 259                 if (sk && ra->sel == sel &&
 260                     (!sk->sk_bound_dev_if ||
 261                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 262                         if (last) {
 263                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 264                                 if (skb2)
 265                                         rawv6_rcv(last, skb2);
 266                         }
 267                         last = sk;
 268                 }
 269         }
 270
 271         if (last) {
 272                 rawv6_rcv(last, skb);
 273                 read_unlock(&ip6_ra_lock);
 274                 return 1;
 275         }
 276         read_unlock(&ip6_ra_lock);
 277         return 0;
 278 }
 279
 280 static int ip6_forward_proxy_check(struct sk_buff *skb)
 281 {
 282         struct ipv6hdr *hdr = ipv6_hdr(skb);
 283         u8 nexthdr = hdr->nexthdr;
 284         __be16 frag_off;
 285         int offset;
 286
 287         if (ipv6_ext_hdr(nexthdr)) {
 288                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
 289                 if (offset < 0)
 290                         return 0;
 291         } else
 292                 offset = sizeof(struct ipv6hdr);
 293
 294         if (nexthdr == IPPROTO_ICMPV6) {
 295                 struct icmp6hdr *icmp6;
 296
 297                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 298                                          offset + 1 - skb->data)))
 299                         return 0;
 300
 301                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 302
 303                 switch (icmp6->icmp6_type) {
 304                 case NDISC_ROUTER_SOLICITATION:
 305                 case NDISC_ROUTER_ADVERTISEMENT:
 306                 case NDISC_NEIGHBOUR_SOLICITATION:
 307                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 308                 case NDISC_REDIRECT:
 309                         /* For reaction involving unicast neighbor discovery
 310                          * message destined to the proxied address, pass it to
 311                          * input function.
 312                          */
 313                         return 1;
 314                 default:
 315                         break;
 316                 }
 317         }
 318
 319         /*
 320          * The proxying router can't forward traffic sent to a link-local
 321          * address, so signal the sender and discard the packet. This
 322          * behavior is clarified by the MIPv6 specification.
 323          */
 324         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 325                 dst_link_failure(skb);
 326                 return -1;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static inline int ip6_forward_finish(struct net *net, struct sock *sk,
 333                                      struct sk_buff *skb)
 334 {
 335         return dst_output(net, sk, skb);
 336 }
 337
 338 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 339 {
 340         unsigned int mtu;
 341         struct inet6_dev *idev;
 342
 343         if (dst_metric_locked(dst, RTAX_MTU)) {
 344                 mtu = dst_metric_raw(dst, RTAX_MTU);
 345                 if (mtu)
 346                         return mtu;
 347         }
 348
 349         mtu = IPV6_MIN_MTU;
 350         rcu_read_lock();
 351         idev = __in6_dev_get(dst->dev);
 352         if (idev)
 353                 mtu = idev->cnf.mtu6;
 354         rcu_read_unlock();
 355
 356         return mtu;
 357 }
 358
 359 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 360 {
 361         if (skb->len <= mtu)
 362                 return false;
 363
 364         /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
 365         if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
 366                 return true;
 367
 368         if (skb->ignore_df)
 369                 return false;
 370
 371         if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
 372                 return false;
 373
 374         return true;
 375 }
 376
 377 int ip6_forward(struct sk_buff *skb)
 378 {
 379         struct dst_entry *dst = skb_dst(skb);
 380         struct ipv6hdr *hdr = ipv6_hdr(skb);
 381         struct inet6_skb_parm *opt = IP6CB(skb);
 382         struct net *net = dev_net(dst->dev);
 383         u32 mtu;
 384
 385         if (net->ipv6.devconf_all->forwarding == 0)
 386                 goto error;
 387
 388         if (skb->pkt_type != PACKET_HOST)
 389                 goto drop;
 390
 391         if (unlikely(skb->sk))
 392                 goto drop;
 393
 394         if (skb_warn_if_lro(skb))
 395                 goto drop;
 396
 397         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 398                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 399                                 IPSTATS_MIB_INDISCARDS);
 400                 goto drop;
 401         }
 402
 403         skb_forward_csum(skb);
 404
 405         /*
 406          *      We DO NOT make any processing on
 407          *      RA packets, pushing them to user level AS IS
 408          *      without ane WARRANTY that application will be able
 409          *      to interpret them. The reason is that we
 410          *      cannot make anything clever here.
 411          *
 412          *      We are not end-node, so that if packet contains
 413          *      AH/ESP, we cannot make anything.
 414          *      Defragmentation also would be mistake, RA packets
 415          *      cannot be fragmented, because there is no warranty
 416          *      that different fragments will go along one path. --ANK
 417          */
 418         if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 419                 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
 420                         return 0;
 421         }
 422
 423         /*
 424          *      check and decrement ttl
 425          */
 426         if (hdr->hop_limit <= 1) {
 427                 /* Force OUTPUT device used as source address */
 428                 skb->dev = dst->dev;
 429                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
 430                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 431                                 IPSTATS_MIB_INHDRERRORS);
 432
 433                 kfree_skb(skb);
 434                 return -ETIMEDOUT;
 435         }
 436
 437         /* XXX: idev->cnf.proxy_ndp? */
 438         if (net->ipv6.devconf_all->proxy_ndp &&
 439             pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 440                 int proxied = ip6_forward_proxy_check(skb);
 441                 if (proxied > 0)
 442                         return ip6_input(skb);
 443                 else if (proxied < 0) {
 444                         __IP6_INC_STATS(net, ip6_dst_idev(dst),
 445                                         IPSTATS_MIB_INDISCARDS);
 446                         goto drop;
 447                 }
 448         }
 449
 450         if (!xfrm6_route_forward(skb)) {
 451                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 452                                 IPSTATS_MIB_INDISCARDS);
 453                 goto drop;
 454         }
 455         dst = skb_dst(skb);
 456
 457         /* IPv6 specs say nothing about it, but it is clear that we cannot
 458            send redirects to source routed frames.
 459            We don't send redirects to frames decapsulated from IPsec.
 460          */
 461         if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
 462                 struct in6_addr *target = NULL;
 463                 struct inet_peer *peer;
 464                 struct rt6_info *rt;
 465
 466                 /*
 467                  *      incoming and outgoing devices are the same
 468                  *      send a redirect.
 469                  */
 470
 471                 rt = (struct rt6_info *) dst;
 472                 if (rt->rt6i_flags & RTF_GATEWAY)
 473                         target = &rt->rt6i_gateway;
 474                 else
 475                         target = &hdr->daddr;
 476
 477                 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
 478
 479                 /* Limit redirects both by destination (here)
 480                    and by source (inside ndisc_send_redirect)
 481                  */
 482                 if (inet_peer_xrlim_allow(peer, 1*HZ))
 483                         ndisc_send_redirect(skb, target);
 484                 if (peer)
 485                         inet_putpeer(peer);
 486         } else {
 487                 int addrtype = ipv6_addr_type(&hdr->saddr);
 488
 489                 /* This check is security critical. */
 490                 if (addrtype == IPV6_ADDR_ANY ||
 491                     addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
 492                         goto error;
 493                 if (addrtype & IPV6_ADDR_LINKLOCAL) {
 494                         icmpv6_send(skb, ICMPV6_DEST_UNREACH,
 495                                     ICMPV6_NOT_NEIGHBOUR, 0);
 496                         goto error;
 497                 }
 498         }
 499
 500         mtu = ip6_dst_mtu_forward(dst);
 501         if (mtu < IPV6_MIN_MTU)
 502                 mtu = IPV6_MIN_MTU;
 503
 504         if (ip6_pkt_too_big(skb, mtu)) {
 505                 /* Again, force OUTPUT device used as source address */
 506                 skb->dev = dst->dev;
 507                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 508                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 509                                 IPSTATS_MIB_INTOOBIGERRORS);
 510                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 511                                 IPSTATS_MIB_FRAGFAILS);
 512                 kfree_skb(skb);
 513                 return -EMSGSIZE;
 514         }
 515
 516         if (skb_cow(skb, dst->dev->hard_header_len)) {
 517                 __IP6_INC_STATS(net, ip6_dst_idev(dst),
 518                                 IPSTATS_MIB_OUTDISCARDS);
 519                 goto drop;
 520         }
 521
 522         hdr = ipv6_hdr(skb);
 523
 524         /* Mangling hops number delayed to point after skb COW */
 525
 526         hdr->hop_limit--;
 527
 528         __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 529         __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
 530         return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
 531                        net, NULL, skb, skb->dev, dst->dev,
 532                        ip6_forward_finish);
 533
 534 error:
 535         __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 536 drop:
 537         kfree_skb(skb);
 538         return -EINVAL;
 539 }
 540
 541 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 542 {
 543         to->pkt_type = from->pkt_type;
 544         to->priority = from->priority;
 545         to->protocol = from->protocol;
 546         skb_dst_drop(to);
 547         skb_dst_set(to, dst_clone(skb_dst(from)));
 548         to->dev = from->dev;
 549         to->mark = from->mark;
 550
 551 #ifdef CONFIG_NET_SCHED
 552         to->tc_index = from->tc_index;
 553 #endif
 554         nf_copy(to, from);
 555         skb_copy_secmark(to, from);
 556 }
 557
 558 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 559                  int (*output)(struct net *, struct sock *, struct sk_buff *))
 560 {
 561         struct sk_buff *frag;
 562         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 563         struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
 564                                 inet6_sk(skb->sk) : NULL;
 565         struct ipv6hdr *tmp_hdr;
 566         struct frag_hdr *fh;
 567         unsigned int mtu, hlen, left, len;
 568         int hroom, troom;
 569         __be32 frag_id;
 570         int ptr, offset = 0, err = 0;
 571         u8 *prevhdr, nexthdr = 0;
 572
 573         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 574         nexthdr = *prevhdr;
 575
 576         mtu = ip6_skb_dst_mtu(skb);
 577
 578         /* We must not fragment if the socket is set to force MTU discovery
 579          * or if the skb it not generated by a local socket.
 580          */
 581         if (unlikely(!skb->ignore_df && skb->len > mtu))
 582                 goto fail_toobig;
 583
 584         if (IP6CB(skb)->frag_max_size) {
 585                 if (IP6CB(skb)->frag_max_size > mtu)
 586                         goto fail_toobig;
 587
 588                 /* don't send fragments larger than what we received */
 589                 mtu = IP6CB(skb)->frag_max_size;
 590                 if (mtu < IPV6_MIN_MTU)
 591                         mtu = IPV6_MIN_MTU;
 592         }
 593
 594         if (np && np->frag_size < mtu) {
 595                 if (np->frag_size)
 596                         mtu = np->frag_size;
 597         }
 598         if (mtu < hlen + sizeof(struct frag_hdr) + 8)
 599                 goto fail_toobig;
 600         mtu -= hlen + sizeof(struct frag_hdr);
 601
 602         frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
 603                                     &ipv6_hdr(skb)->saddr);
 604
 605         if (skb->ip_summed == CHECKSUM_PARTIAL &&
 606             (err = skb_checksum_help(skb)))
 607                 goto fail;
 608
 609         hroom = LL_RESERVED_SPACE(rt->dst.dev);
 610         if (skb_has_frag_list(skb)) {
 611                 int first_len = skb_pagelen(skb);
 612                 struct sk_buff *frag2;
 613
 614                 if (first_len - hlen > mtu ||
 615                     ((first_len - hlen) & 7) ||
 616                     skb_cloned(skb) ||
 617                     skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
 618                         goto slow_path;
 619
 620                 skb_walk_frags(skb, frag) {
 621                         /* Correct geometry. */
 622                         if (frag->len > mtu ||
 623                             ((frag->len & 7) && frag->next) ||
 624                             skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
 625                                 goto slow_path_clean;
 626
 627                         /* Partially cloned skb? */
 628                         if (skb_shared(frag))
 629                                 goto slow_path_clean;
 630
 631                         BUG_ON(frag->sk);
 632                         if (skb->sk) {
 633                                 frag->sk = skb->sk;
 634                                 frag->destructor = sock_wfree;
 635                         }
 636                         skb->truesize -= frag->truesize;
 637                 }
 638
 639                 err = 0;
 640                 offset = 0;
 641                 /* BUILD HEADER */
 642
 643                 *prevhdr = NEXTHDR_FRAGMENT;
 644                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 645                 if (!tmp_hdr) {
 646                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 647                                       IPSTATS_MIB_FRAGFAILS);
 648                         err = -ENOMEM;
 649                         goto fail;
 650                 }
 651                 frag = skb_shinfo(skb)->frag_list;
 652                 skb_frag_list_init(skb);
 653
 654                 __skb_pull(skb, hlen);
 655                 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
 656                 __skb_push(skb, hlen);
 657                 skb_reset_network_header(skb);
 658                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 659
 660                 fh->nexthdr = nexthdr;
 661                 fh->reserved = 0;
 662                 fh->frag_off = htons(IP6_MF);
 663                 fh->identification = frag_id;
 664
 665                 first_len = skb_pagelen(skb);
 666                 skb->data_len = first_len - skb_headlen(skb);
 667                 skb->len = first_len;
 668                 ipv6_hdr(skb)->payload_len = htons(first_len -
 669                                                    sizeof(struct ipv6hdr));
 670
 671                 dst_hold(&rt->dst);
 672
 673                 for (;;) {
 674                         /* Prepare header of the next frame,
 675                          * before previous one went down. */
 676                         if (frag) {
 677                                 frag->ip_summed = CHECKSUM_NONE;
 678                                 skb_reset_transport_header(frag);
 679                                 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
 680                                 __skb_push(frag, hlen);
 681                                 skb_reset_network_header(frag);
 682                                 memcpy(skb_network_header(frag), tmp_hdr,
 683                                        hlen);
 684                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 685                                 fh->nexthdr = nexthdr;
 686                                 fh->reserved = 0;
 687                                 fh->frag_off = htons(offset);
 688                                 if (frag->next)
 689                                         fh->frag_off |= htons(IP6_MF);
 690                                 fh->identification = frag_id;
 691                                 ipv6_hdr(frag)->payload_len =
 692                                                 htons(frag->len -
 693                                                       sizeof(struct ipv6hdr));
 694                                 ip6_copy_metadata(frag, skb);
 695                         }
 696
 697                         err = output(net, sk, skb);
 698                         if (!err)
 699                                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 700                                               IPSTATS_MIB_FRAGCREATES);
 701
 702                         if (err || !frag)
 703                                 break;
 704
 705                         skb = frag;
 706                         frag = skb->next;
 707                         skb->next = NULL;
 708                 }
 709
 710                 kfree(tmp_hdr);
 711
 712                 if (err == 0) {
 713                         IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 714                                       IPSTATS_MIB_FRAGOKS);
 715                         ip6_rt_put(rt);
 716                         return 0;
 717                 }
 718
 719                 kfree_skb_list(frag);
 720
 721                 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
 722                               IPSTATS_MIB_FRAGFAILS);
 723                 ip6_rt_put(rt);
 724                 return err;
 725
 726 slow_path_clean:
 727                 skb_walk_frags(skb, frag2) {
 728                         if (frag2 == frag)
 729                                 break;
 730                         frag2->sk = NULL;
 731                         frag2->destructor = NULL;
 732                         skb->truesize += frag2->truesize;
 733                 }
 734         }
 735
 736 slow_path:
 737         left = skb->len - hlen;         /* Space per frame */
 738         ptr = hlen;                     /* Where to start from */
 739
 740         /*
 741          *      Fragment the datagram.
 742          */
 743
 744         *prevhdr = NEXTHDR_FRAGMENT;
 745         troom = rt->dst.dev->needed_tailroom;
 746
 747         /*
 748          *      Keep copying data until we run out.
 749          */
 750         while (left > 0)        {
 751                 len = left;
 752                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 753                 if (len > mtu)
 754                         len = mtu;
 755                 /* IF: we are not sending up to and including the packet end
 756                    then align the next start on an eight byte boundary */
 757                 if (len < left) {
 758                         len &= ~7;
 759                 }
 760
 761                 /* Allocate buffer */
 762                 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
 763                                  hroom + troom, GFP_ATOMIC);
 764                 if (!frag) {
 765                         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 766                                       IPSTATS_MIB_FRAGFAILS);
 767                         err = -ENOMEM;
 768                         goto fail;
 769                 }
 770
 771                 /*
 772                  *      Set up data on packet
 773                  */
 774
 775                 ip6_copy_metadata(frag, skb);
 776                 skb_reserve(frag, hroom);
 777                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 778                 skb_reset_network_header(frag);
 779                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 780                 frag->transport_header = (frag->network_header + hlen +
 781                                           sizeof(struct frag_hdr));
 782
 783                 /*
 784                  *      Charge the memory for the fragment to any owner
 785                  *      it might possess
 786                  */
 787                 if (skb->sk)
 788                         skb_set_owner_w(frag, skb->sk);
 789
 790                 /*
 791                  *      Copy the packet header into the new buffer.
 792                  */
 793                 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
 794
 795                 /*
 796                  *      Build fragment header.
 797                  */
 798                 fh->nexthdr = nexthdr;
 799                 fh->reserved = 0;
 800                 fh->identification = frag_id;
 801
 802                 /*
 803                  *      Copy a block of the IP datagram.
 804                  */
 805                 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
 806                                      len));
 807                 left -= len;
 808
 809                 fh->frag_off = htons(offset);
 810                 if (left > 0)
 811                         fh->frag_off |= htons(IP6_MF);
 812                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 813                                                     sizeof(struct ipv6hdr));
 814
 815                 ptr += len;
 816                 offset += len;
 817
 818                 /*
 819                  *      Put this fragment into the sending queue.
 820                  */
 821                 err = output(net, sk, frag);
 822                 if (err)
 823                         goto fail;
 824
 825                 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 826                               IPSTATS_MIB_FRAGCREATES);
 827         }
 828         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 829                       IPSTATS_MIB_FRAGOKS);
 830         consume_skb(skb);
 831         return err;
 832
 833 fail_toobig:
 834         if (skb->sk && dst_allfrag(skb_dst(skb)))
 835                 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
 836
 837         skb->dev = skb_dst(skb)->dev;
 838         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 839         err = -EMSGSIZE;
 840
 841 fail:
 842         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 843                       IPSTATS_MIB_FRAGFAILS);
 844         kfree_skb(skb);
 845         return err;
 846 }
 847
 848 static inline int ip6_rt_check(const struct rt6key *rt_key,
 849                                const struct in6_addr *fl_addr,
 850                                const struct in6_addr *addr_cache)
 851 {
 852         return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 853                 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
 854 }
 855
 856 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 857                                           struct dst_entry *dst,
 858                                           const struct flowi6 *fl6)
 859 {
 860         struct ipv6_pinfo *np = inet6_sk(sk);
 861         struct rt6_info *rt;
 862
 863         if (!dst)
 864                 goto out;
 865
 866         if (dst->ops->family != AF_INET6) {
 867                 dst_release(dst);
 868                 return NULL;
 869         }
 870
 871         rt = (struct rt6_info *)dst;
 872         /* Yes, checking route validity in not connected
 873          * case is not very simple. Take into account,
 874          * that we do not support routing by source, TOS,
 875          * and MSG_DONTROUTE            --ANK (980726)
 876          *
 877          * 1. ip6_rt_check(): If route was host route,
 878          *    check that cached destination is current.
 879          *    If it is network route, we still may
 880          *    check its validity using saved pointer
 881          *    to the last used address: daddr_cache.
 882          *    We do not want to save whole address now,
 883          *    (because main consumer of this service
 884          *    is tcp, which has not this problem),
 885          *    so that the last trick works only on connected
 886          *    sockets.
 887          * 2. oif also should be the same.
 888          */
 889         if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
 890 #ifdef CONFIG_IPV6_SUBTREES
 891             ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 892 #endif
 893            (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
 894               (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
 895                 dst_release(dst);
 896                 dst = NULL;
 897         }
 898
 899 out:
 900         return dst;
 901 }
 902
 903 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
 904                                struct dst_entry **dst, struct flowi6 *fl6)
 905 {
 906 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 907         struct neighbour *n;
 908         struct rt6_info *rt;
 909 #endif
 910         int err;
 911         int flags = 0;
 912
 913         /* The correct way to handle this would be to do
 914          * ip6_route_get_saddr, and then ip6_route_output; however,
 915          * the route-specific preferred source forces the
 916          * ip6_route_output call _before_ ip6_route_get_saddr.
 917          *
 918          * In source specific routing (no src=any default route),
 919          * ip6_route_output will fail given src=any saddr, though, so
 920          * that's why we try it again later.
 921          */
 922         if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
 923                 struct rt6_info *rt;
 924                 bool had_dst = *dst != NULL;
 925
 926                 if (!had_dst)
 927                         *dst = ip6_route_output(net, sk, fl6);
 928                 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
 929                 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
 930                                           sk ? inet6_sk(sk)->srcprefs : 0,
 931                                           &fl6->saddr);
 932                 if (err)
 933                         goto out_err_release;
 934
 935                 /* If we had an erroneous initial result, pretend it
 936                  * never existed and let the SA-enabled version take
 937                  * over.
 938                  */
 939                 if (!had_dst && (*dst)->error) {
 940                         dst_release(*dst);
 941                         *dst = NULL;
 942                 }
 943
 944                 if (fl6->flowi6_oif)
 945                         flags |= RT6_LOOKUP_F_IFACE;
 946         }
 947
 948         if (!*dst)
 949                 *dst = ip6_route_output_flags(net, sk, fl6, flags);
 950
 951         err = (*dst)->error;
 952         if (err)
 953                 goto out_err_release;
 954
 955 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 956         /*
 957          * Here if the dst entry we've looked up
 958          * has a neighbour entry that is in the INCOMPLETE
 959          * state and the src address from the flow is
 960          * marked as OPTIMISTIC, we release the found
 961          * dst entry and replace it instead with the
 962          * dst entry of the nexthop router
 963          */
 964         rt = (struct rt6_info *) *dst;
 965         rcu_read_lock_bh();
 966         n = __ipv6_neigh_lookup_noref(rt->dst.dev,
 967                                       rt6_nexthop(rt, &fl6->daddr));
 968         err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
 969         rcu_read_unlock_bh();
 970
 971         if (err) {
 972                 struct inet6_ifaddr *ifp;
 973                 struct flowi6 fl_gw6;
 974                 int redirect;
 975
 976                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 977                                       (*dst)->dev, 1);
 978
 979                 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 980                 if (ifp)
 981                         in6_ifa_put(ifp);
 982
 983                 if (redirect) {
 984                         /*
 985                          * We need to get the dst entry for the
 986                          * default router instead
 987                          */
 988                         dst_release(*dst);
 989                         memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
 990                         memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
 991                         *dst = ip6_route_output(net, sk, &fl_gw6);
 992                         err = (*dst)->error;
 993                         if (err)
 994                                 goto out_err_release;
 995                 }
 996         }
 997 #endif
 998
 999         return 0;
1000
1001 out_err_release:
1002         if (err == -ENETUNREACH)
1003                 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1004         dst_release(*dst);
1005         *dst = NULL;
1006         return err;
1007 }
1008
1009 /**
1010  *      ip6_dst_lookup - perform route lookup on flow
1011  *      @sk: socket which provides route info
1012  *      @dst: pointer to dst_entry * for result
1013  *      @fl6: flow to lookup
1014  *
1015  *      This function performs a route lookup on the given flow.
1016  *
1017  *      It returns zero on success, or a standard errno code on error.
1018  */
1019 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1020                    struct flowi6 *fl6)
1021 {
1022         *dst = NULL;
1023         return ip6_dst_lookup_tail(net, sk, dst, fl6);
1024 }
1025 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1026
1027 /**
1028  *      ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1029  *      @sk: socket which provides route info
1030  *      @fl6: flow to lookup
1031  *      @final_dst: final destination address for ipsec lookup
1032  *
1033  *      This function performs a route lookup on the given flow.
1034  *
1035  *      It returns a valid dst pointer on success, or a pointer encoded
1036  *      error code.
1037  */
1038 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1039                                       const struct in6_addr *final_dst)
1040 {
1041         struct dst_entry *dst = NULL;
1042         int err;
1043
1044         err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1045         if (err)
1046                 return ERR_PTR(err);
1047         if (final_dst)
1048                 fl6->daddr = *final_dst;
1049         if (!fl6->flowi6_oif)
1050                 fl6->flowi6_oif = l3mdev_fib_oif(dst->dev);
1051
1052         return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1053 }
1054 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1055
1056 /**
1057  *      ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1058  *      @sk: socket which provides the dst cache and route info
1059  *      @fl6: flow to lookup
1060  *      @final_dst: final destination address for ipsec lookup
1061  *
1062  *      This function performs a route lookup on the given flow with the
1063  *      possibility of using the cached route in the socket if it is valid.
1064  *      It will take the socket dst lock when operating on the dst cache.
1065  *      As a result, this function can only be used in process context.
1066  *
1067  *      It returns a valid dst pointer on success, or a pointer encoded
1068  *      error code.
1069  */
1070 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1071                                          const struct in6_addr *final_dst)
1072 {
1073         struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1074
1075         dst = ip6_sk_dst_check(sk, dst, fl6);
1076         if (!dst)
1077                 dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
1078
1079         return dst;
1080 }
1081 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1082
1083 static inline int ip6_ufo_append_data(struct sock *sk,
1084                         struct sk_buff_head *queue,
1085                         int getfrag(void *from, char *to, int offset, int len,
1086                         int odd, struct sk_buff *skb),
1087                         void *from, int length, int hh_len, int fragheaderlen,
1088                         int exthdrlen, int transhdrlen, int mtu,
1089                         unsigned int flags, const struct flowi6 *fl6)
1090
1091 {
1092         struct sk_buff *skb;
1093         int err;
1094
1095         /* There is support for UDP large send offload by network
1096          * device, so create one single skb packet containing complete
1097          * udp datagram
1098          */
1099         skb = skb_peek_tail(queue);
1100         if (!skb) {
1101                 skb = sock_alloc_send_skb(sk,
1102                         hh_len + fragheaderlen + transhdrlen + 20,
1103                         (flags & MSG_DONTWAIT), &err);
1104                 if (!skb)
1105                         return err;
1106
1107                 /* reserve space for Hardware header */
1108                 skb_reserve(skb, hh_len);
1109
1110                 /* create space for UDP/IP header */
1111                 skb_put(skb, fragheaderlen + transhdrlen);
1112
1113                 /* initialize network header pointer */
1114                 skb_set_network_header(skb, exthdrlen);
1115
1116                 /* initialize protocol header pointer */
1117                 skb->transport_header = skb->network_header + fragheaderlen;
1118
1119                 skb->protocol = htons(ETH_P_IPV6);
1120                 skb->csum = 0;
1121
1122                 __skb_queue_tail(queue, skb);
1123         } else if (skb_is_gso(skb)) {
1124                 goto append;
1125         }
1126
1127         skb->ip_summed = CHECKSUM_PARTIAL;
1128         /* Specify the length of each IPv6 datagram fragment.
1129          * It has to be a multiple of 8.
1130          */
1131         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1132                                      sizeof(struct frag_hdr)) & ~7;
1133         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1134         skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk),
1135                                                          &fl6->daddr,
1136                                                          &fl6->saddr);
1137
1138 append:
1139         return skb_append_datato_frags(sk, skb, getfrag, from,
1140                                        (length - transhdrlen));
1141 }
1142
1143 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1144                                                gfp_t gfp)
1145 {
1146         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1147 }
1148
1149 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1150                                                 gfp_t gfp)
1151 {
1152         return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1153 }
1154
1155 static void ip6_append_data_mtu(unsigned int *mtu,
1156                                 int *maxfraglen,
1157                                 unsigned int fragheaderlen,
1158                                 struct sk_buff *skb,
1159                                 struct rt6_info *rt,
1160                                 unsigned int orig_mtu)
1161 {
1162         if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1163                 if (!skb) {
1164                         /* first fragment, reserve header_len */
1165                         *mtu = orig_mtu - rt->dst.header_len;
1166
1167                 } else {
1168                         /*
1169                          * this fragment is not first, the headers
1170                          * space is regarded as data space.
1171                          */
1172                         *mtu = orig_mtu;
1173                 }
1174                 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1175                               + fragheaderlen - sizeof(struct frag_hdr);
1176         }
1177 }
1178
1179 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1180                           struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1181                           struct rt6_info *rt, struct flowi6 *fl6)
1182 {
1183         struct ipv6_pinfo *np = inet6_sk(sk);
1184         unsigned int mtu;
1185         struct ipv6_txoptions *opt = ipc6->opt;
1186
1187         /*
1188          * setup for corking
1189          */
1190         if (opt) {
1191                 if (WARN_ON(v6_cork->opt))
1192                         return -EINVAL;
1193
1194                 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1195                 if (unlikely(!v6_cork->opt))
1196                         return -ENOBUFS;
1197
1198                 v6_cork->opt->tot_len = opt->tot_len;
1199                 v6_cork->opt->opt_flen = opt->opt_flen;
1200                 v6_cork->opt->opt_nflen = opt->opt_nflen;
1201
1202                 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1203                                                     sk->sk_allocation);
1204                 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1205                         return -ENOBUFS;
1206
1207                 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1208                                                     sk->sk_allocation);
1209                 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1210                         return -ENOBUFS;
1211
1212                 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1213                                                    sk->sk_allocation);
1214                 if (opt->hopopt && !v6_cork->opt->hopopt)
1215                         return -ENOBUFS;
1216
1217                 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1218                                                     sk->sk_allocation);
1219                 if (opt->srcrt && !v6_cork->opt->srcrt)
1220                         return -ENOBUFS;
1221
1222                 /* need source address above miyazawa*/
1223         }
1224         dst_hold(&rt->dst);
1225         cork->base.dst = &rt->dst;
1226         cork->fl.u.ip6 = *fl6;
1227         v6_cork->hop_limit = ipc6->hlimit;
1228         v6_cork->tclass = ipc6->tclass;
1229         if (rt->dst.flags & DST_XFRM_TUNNEL)
1230                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1231                       rt->dst.dev->mtu : dst_mtu(&rt->dst);
1232         else
1233                 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1234                       rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1235         if (np->frag_size < mtu) {
1236                 if (np->frag_size)
1237                         mtu = np->frag_size;
1238         }
1239         cork->base.fragsize = mtu;
1240         if (dst_allfrag(rt->dst.path))
1241                 cork->base.flags |= IPCORK_ALLFRAG;
1242         cork->base.length = 0;
1243
1244         return 0;
1245 }
1246
1247 static int __ip6_append_data(struct sock *sk,
1248                              struct flowi6 *fl6,
1249                              struct sk_buff_head *queue,
1250                              struct inet_cork *cork,
1251                              struct inet6_cork *v6_cork,
1252                              struct page_frag *pfrag,
1253                              int getfrag(void *from, char *to, int offset,
1254                                          int len, int odd, struct sk_buff *skb),
1255                              void *from, int length, int transhdrlen,
1256                              unsigned int flags, struct ipcm6_cookie *ipc6,
1257                              const struct sockcm_cookie *sockc)
1258 {
1259         struct sk_buff *skb, *skb_prev = NULL;
1260         unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1261         int exthdrlen = 0;
1262         int dst_exthdrlen = 0;
1263         int hh_len;
1264         int copy;
1265         int err;
1266         int offset = 0;
1267         __u8 tx_flags = 0;
1268         u32 tskey = 0;
1269         struct rt6_info *rt = (struct rt6_info *)cork->dst;
1270         struct ipv6_txoptions *opt = v6_cork->opt;
1271         int csummode = CHECKSUM_NONE;
1272         unsigned int maxnonfragsize, headersize;
1273
1274         skb = skb_peek_tail(queue);
1275         if (!skb) {
1276                 exthdrlen = opt ? opt->opt_flen : 0;
1277                 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1278         }
1279
1280         mtu = cork->fragsize;
1281         orig_mtu = mtu;
1282
1283         hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1284
1285         fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1286                         (opt ? opt->opt_nflen : 0);
1287         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1288                      sizeof(struct frag_hdr);
1289
1290         headersize = sizeof(struct ipv6hdr) +
1291                      (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1292                      (dst_allfrag(&rt->dst) ?
1293                       sizeof(struct frag_hdr) : 0) +
1294                      rt->rt6i_nfheader_len;
1295
1296         if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1297             (sk->sk_protocol == IPPROTO_UDP ||
1298              sk->sk_protocol == IPPROTO_RAW)) {
1299                 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1300                                 sizeof(struct ipv6hdr));
1301                 goto emsgsize;
1302         }
1303
1304         if (ip6_sk_ignore_df(sk))
1305                 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1306         else
1307                 maxnonfragsize = mtu;
1308
1309         if (cork->length + length > maxnonfragsize - headersize) {
1310 emsgsize:
1311                 ipv6_local_error(sk, EMSGSIZE, fl6,
1312                                  mtu - headersize +
1313                                  sizeof(struct ipv6hdr));
1314                 return -EMSGSIZE;
1315         }
1316
1317         /* CHECKSUM_PARTIAL only with no extension headers and when
1318          * we are not going to fragment
1319          */
1320         if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1321             headersize == sizeof(struct ipv6hdr) &&
1322             length < mtu - headersize &&
1323             !(flags & MSG_MORE) &&
1324             rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1325                 csummode = CHECKSUM_PARTIAL;
1326
1327         if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1328                 sock_tx_timestamp(sk, sockc->tsflags, &tx_flags);
1329                 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1330                     sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1331                         tskey = sk->sk_tskey++;
1332         }
1333
1334         /*
1335          * Let's try using as much space as possible.
1336          * Use MTU if total length of the message fits into the MTU.
1337          * Otherwise, we need to reserve fragment header and
1338          * fragment alignment (= 8-15 octects, in total).
1339          *
1340          * Note that we may need to "move" the data from the tail of
1341          * of the buffer to the new fragment when we split
1342          * the message.
1343          *
1344          * FIXME: It may be fragmented into multiple chunks
1345          *        at once if non-fragmentable extension headers
1346          *        are too large.
1347          * --yoshfuji
1348          */
1349
1350         cork->length += length;
1351         if (((length > mtu) ||
1352              (skb && skb_is_gso(skb))) &&
1353             (sk->sk_protocol == IPPROTO_UDP) &&
1354             (rt->dst.dev->features & NETIF_F_UFO) &&
1355             (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) {
1356                 err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
1357                                           hh_len, fragheaderlen, exthdrlen,
1358                                           transhdrlen, mtu, flags, fl6);
1359                 if (err)
1360                         goto error;
1361                 return 0;
1362         }
1363
1364         if (!skb)
1365                 goto alloc_new_skb;
1366
1367         while (length > 0) {
1368                 /* Check if the remaining data fits into current packet. */
1369                 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1370                 if (copy < length)
1371                         copy = maxfraglen - skb->len;
1372
1373                 if (copy <= 0) {
1374                         char *data;
1375                         unsigned int datalen;
1376                         unsigned int fraglen;
1377                         unsigned int fraggap;
1378                         unsigned int alloclen;
1379 alloc_new_skb:
1380                         /* There's no room in the current skb */
1381                         if (skb)
1382                                 fraggap = skb->len - maxfraglen;
1383                         else
1384                                 fraggap = 0;
1385                         /* update mtu and maxfraglen if necessary */
1386                         if (!skb || !skb_prev)
1387                                 ip6_append_data_mtu(&mtu, &maxfraglen,
1388                                                     fragheaderlen, skb, rt,
1389                                                     orig_mtu);
1390
1391                         skb_prev = skb;
1392
1393                         /*
1394                          * If remaining data exceeds the mtu,
1395                          * we know we need more fragment(s).
1396                          */
1397                         datalen = length + fraggap;
1398
1399                         if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1400                                 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1401                         if ((flags & MSG_MORE) &&
1402                             !(rt->dst.dev->features&NETIF_F_SG))
1403                                 alloclen = mtu;
1404                         else
1405                                 alloclen = datalen + fragheaderlen;
1406
1407                         alloclen += dst_exthdrlen;
1408
1409                         if (datalen != length + fraggap) {
1410                                 /*
1411                                  * this is not the last fragment, the trailer
1412                                  * space is regarded as data space.
1413                                  */
1414                                 datalen += rt->dst.trailer_len;
1415                         }
1416
1417                         alloclen += rt->dst.trailer_len;
1418                         fraglen = datalen + fragheaderlen;
1419
1420                         /*
1421                          * We just reserve space for fragment header.
1422                          * Note: this may be overallocation if the message
1423                          * (without MSG_MORE) fits into the MTU.
1424                          */
1425                         alloclen += sizeof(struct frag_hdr);
1426
1427                         if (transhdrlen) {
1428                                 skb = sock_alloc_send_skb(sk,
1429                                                 alloclen + hh_len,
1430                                                 (flags & MSG_DONTWAIT), &err);
1431                         } else {
1432                                 skb = NULL;
1433                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1434                                     2 * sk->sk_sndbuf)
1435                                         skb = sock_wmalloc(sk,
1436                                                            alloclen + hh_len, 1,
1437                                                            sk->sk_allocation);
1438                                 if (unlikely(!skb))
1439                                         err = -ENOBUFS;
1440                         }
1441                         if (!skb)
1442                                 goto error;
1443                         /*
1444                          *      Fill in the control structures
1445                          */
1446                         skb->protocol = htons(ETH_P_IPV6);
1447                         skb->ip_summed = csummode;
1448                         skb->csum = 0;
1449                         /* reserve for fragmentation and ipsec header */
1450                         skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1451                                     dst_exthdrlen);
1452
1453                         /* Only the initial fragment is time stamped */
1454                         skb_shinfo(skb)->tx_flags = tx_flags;
1455                         tx_flags = 0;
1456                         skb_shinfo(skb)->tskey = tskey;
1457                         tskey = 0;
1458
1459                         /*
1460                          *      Find where to start putting bytes
1461                          */
1462                         data = skb_put(skb, fraglen);
1463                         skb_set_network_header(skb, exthdrlen);
1464                         data += fragheaderlen;
1465                         skb->transport_header = (skb->network_header +
1466                                                  fragheaderlen);
1467                         if (fraggap) {
1468                                 skb->csum = skb_copy_and_csum_bits(
1469                                         skb_prev, maxfraglen,
1470                                         data + transhdrlen, fraggap, 0);
1471                                 skb_prev->csum = csum_sub(skb_prev->csum,
1472                                                           skb->csum);
1473                                 data += fraggap;
1474                                 pskb_trim_unique(skb_prev, maxfraglen);
1475                         }
1476                         copy = datalen - transhdrlen - fraggap;
1477
1478                         if (copy < 0) {
1479                                 err = -EINVAL;
1480                                 kfree_skb(skb);
1481                                 goto error;
1482                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1483                                 err = -EFAULT;
1484                                 kfree_skb(skb);
1485                                 goto error;
1486                         }
1487
1488                         offset += copy;
1489                         length -= datalen - fraggap;
1490                         transhdrlen = 0;
1491                         exthdrlen = 0;
1492                         dst_exthdrlen = 0;
1493
1494                         /*
1495                          * Put the packet on the pending queue
1496                          */
1497                         __skb_queue_tail(queue, skb);
1498                         continue;
1499                 }
1500
1501                 if (copy > length)
1502                         copy = length;
1503
1504                 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1505                         unsigned int off;
1506
1507                         off = skb->len;
1508                         if (getfrag(from, skb_put(skb, copy),
1509                                                 offset, copy, off, skb) < 0) {
1510                                 __skb_trim(skb, off);
1511                                 err = -EFAULT;
1512                                 goto error;
1513                         }
1514                 } else {
1515                         int i = skb_shinfo(skb)->nr_frags;
1516
1517                         err = -ENOMEM;
1518                         if (!sk_page_frag_refill(sk, pfrag))
1519                                 goto error;
1520
1521                         if (!skb_can_coalesce(skb, i, pfrag->page,
1522                                               pfrag->offset)) {
1523                                 err = -EMSGSIZE;
1524                                 if (i == MAX_SKB_FRAGS)
1525                                         goto error;
1526
1527                                 __skb_fill_page_desc(skb, i, pfrag->page,
1528                                                      pfrag->offset, 0);
1529                                 skb_shinfo(skb)->nr_frags = ++i;
1530                                 get_page(pfrag->page);
1531                         }
1532                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1533                         if (getfrag(from,
1534                                     page_address(pfrag->page) + pfrag->offset,
1535                                     offset, copy, skb->len, skb) < 0)
1536                                 goto error_efault;
1537
1538                         pfrag->offset += copy;
1539                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1540                         skb->len += copy;
1541                         skb->data_len += copy;
1542                         skb->truesize += copy;
1543                         atomic_add(copy, &sk->sk_wmem_alloc);
1544                 }
1545                 offset += copy;
1546                 length -= copy;
1547         }
1548
1549         return 0;
1550
1551 error_efault:
1552         err = -EFAULT;
1553 error:
1554         cork->length -= length;
1555         IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1556         return err;
1557 }
1558
1559 int ip6_append_data(struct sock *sk,
1560                     int getfrag(void *from, char *to, int offset, int len,
1561                                 int odd, struct sk_buff *skb),
1562                     void *from, int length, int transhdrlen,
1563                     struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1564                     struct rt6_info *rt, unsigned int flags,
1565                     const struct sockcm_cookie *sockc)
1566 {
1567         struct inet_sock *inet = inet_sk(sk);
1568         struct ipv6_pinfo *np = inet6_sk(sk);
1569         int exthdrlen;
1570         int err;
1571
1572         if (flags&MSG_PROBE)
1573                 return 0;
1574         if (skb_queue_empty(&sk->sk_write_queue)) {
1575                 /*
1576                  * setup for corking
1577                  */
1578                 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1579                                      ipc6, rt, fl6);
1580                 if (err)
1581                         return err;
1582
1583                 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1584                 length += exthdrlen;
1585                 transhdrlen += exthdrlen;
1586         } else {
1587                 fl6 = &inet->cork.fl.u.ip6;
1588                 transhdrlen = 0;
1589         }
1590
1591         return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1592                                  &np->cork, sk_page_frag(sk), getfrag,
1593                                  from, length, transhdrlen, flags, ipc6, sockc);
1594 }
1595 EXPORT_SYMBOL_GPL(ip6_append_data);
1596
1597 static void ip6_cork_release(struct inet_cork_full *cork,
1598                              struct inet6_cork *v6_cork)
1599 {
1600         if (v6_cork->opt) {
1601                 kfree(v6_cork->opt->dst0opt);
1602                 kfree(v6_cork->opt->dst1opt);
1603                 kfree(v6_cork->opt->hopopt);
1604                 kfree(v6_cork->opt->srcrt);
1605                 kfree(v6_cork->opt);
1606                 v6_cork->opt = NULL;
1607         }
1608
1609         if (cork->base.dst) {
1610                 dst_release(cork->base.dst);
1611                 cork->base.dst = NULL;
1612                 cork->base.flags &= ~IPCORK_ALLFRAG;
1613         }
1614         memset(&cork->fl, 0, sizeof(cork->fl));
1615 }
1616
1617 struct sk_buff *__ip6_make_skb(struct sock *sk,
1618                                struct sk_buff_head *queue,
1619                                struct inet_cork_full *cork,
1620                                struct inet6_cork *v6_cork)
1621 {
1622         struct sk_buff *skb, *tmp_skb;
1623         struct sk_buff **tail_skb;
1624         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1625         struct ipv6_pinfo *np = inet6_sk(sk);
1626         struct net *net = sock_net(sk);
1627         struct ipv6hdr *hdr;
1628         struct ipv6_txoptions *opt = v6_cork->opt;
1629         struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1630         struct flowi6 *fl6 = &cork->fl.u.ip6;
1631         unsigned char proto = fl6->flowi6_proto;
1632
1633         skb = __skb_dequeue(queue);
1634         if (!skb)
1635                 goto out;
1636         tail_skb = &(skb_shinfo(skb)->frag_list);
1637
1638         /* move skb->data to ip header from ext header */
1639         if (skb->data < skb_network_header(skb))
1640                 __skb_pull(skb, skb_network_offset(skb));
1641         while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1642                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1643                 *tail_skb = tmp_skb;
1644                 tail_skb = &(tmp_skb->next);
1645                 skb->len += tmp_skb->len;
1646                 skb->data_len += tmp_skb->len;
1647                 skb->truesize += tmp_skb->truesize;
1648                 tmp_skb->destructor = NULL;
1649                 tmp_skb->sk = NULL;
1650         }
1651
1652         /* Allow local fragmentation. */
1653         skb->ignore_df = ip6_sk_ignore_df(sk);
1654
1655         *final_dst = fl6->daddr;
1656         __skb_pull(skb, skb_network_header_len(skb));
1657         if (opt && opt->opt_flen)
1658                 ipv6_push_frag_opts(skb, opt, &proto);
1659         if (opt && opt->opt_nflen)
1660                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1661
1662         skb_push(skb, sizeof(struct ipv6hdr));
1663         skb_reset_network_header(skb);
1664         hdr = ipv6_hdr(skb);
1665
1666         ip6_flow_hdr(hdr, v6_cork->tclass,
1667                      ip6_make_flowlabel(net, skb, fl6->flowlabel,
1668                                         np->autoflowlabel, fl6));
1669         hdr->hop_limit = v6_cork->hop_limit;
1670         hdr->nexthdr = proto;
1671         hdr->saddr = fl6->saddr;
1672         hdr->daddr = *final_dst;
1673
1674         skb->priority = sk->sk_priority;
1675         skb->mark = sk->sk_mark;
1676
1677         skb_dst_set(skb, dst_clone(&rt->dst));
1678         IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1679         if (proto == IPPROTO_ICMPV6) {
1680                 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1681
1682                 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1683                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1684         }
1685
1686         ip6_cork_release(cork, v6_cork);
1687 out:
1688         return skb;
1689 }
1690
1691 int ip6_send_skb(struct sk_buff *skb)
1692 {
1693         struct net *net = sock_net(skb->sk);
1694         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1695         int err;
1696
1697         err = ip6_local_out(net, skb->sk, skb);
1698         if (err) {
1699                 if (err > 0)
1700                         err = net_xmit_errno(err);
1701                 if (err)
1702                         IP6_INC_STATS(net, rt->rt6i_idev,
1703                                       IPSTATS_MIB_OUTDISCARDS);
1704         }
1705
1706         return err;
1707 }
1708
1709 int ip6_push_pending_frames(struct sock *sk)
1710 {
1711         struct sk_buff *skb;
1712
1713         skb = ip6_finish_skb(sk);
1714         if (!skb)
1715                 return 0;
1716
1717         return ip6_send_skb(skb);
1718 }
1719 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1720
1721 static void __ip6_flush_pending_frames(struct sock *sk,
1722                                        struct sk_buff_head *queue,
1723                                        struct inet_cork_full *cork,
1724                                        struct inet6_cork *v6_cork)
1725 {
1726         struct sk_buff *skb;
1727
1728         while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1729                 if (skb_dst(skb))
1730                         IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1731                                       IPSTATS_MIB_OUTDISCARDS);
1732                 kfree_skb(skb);
1733         }
1734
1735         ip6_cork_release(cork, v6_cork);
1736 }
1737
1738 void ip6_flush_pending_frames(struct sock *sk)
1739 {
1740         __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1741                                    &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1742 }
1743 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1744
1745 struct sk_buff *ip6_make_skb(struct sock *sk,
1746                              int getfrag(void *from, char *to, int offset,
1747                                          int len, int odd, struct sk_buff *skb),
1748                              void *from, int length, int transhdrlen,
1749                              struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1750                              struct rt6_info *rt, unsigned int flags,
1751                              const struct sockcm_cookie *sockc)
1752 {
1753         struct inet_cork_full cork;
1754         struct inet6_cork v6_cork;
1755         struct sk_buff_head queue;
1756         int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1757         int err;
1758
1759         if (flags & MSG_PROBE)
1760                 return NULL;
1761
1762         __skb_queue_head_init(&queue);
1763
1764         cork.base.flags = 0;
1765         cork.base.addr = 0;
1766         cork.base.opt = NULL;
1767         v6_cork.opt = NULL;
1768         err = ip6_setup_cork(sk, &cork, &v6_cork, ipc6, rt, fl6);
1769         if (err)
1770                 return ERR_PTR(err);
1771
1772         if (ipc6->dontfrag < 0)
1773                 ipc6->dontfrag = inet6_sk(sk)->dontfrag;
1774
1775         err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
1776                                 &current->task_frag, getfrag, from,
1777                                 length + exthdrlen, transhdrlen + exthdrlen,
1778                                 flags, ipc6, sockc);
1779         if (err) {
1780                 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
1781                 return ERR_PTR(err);
1782         }
1783
1784         return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
1785 }