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   1 /*
   2  *      IPv6 output functions
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $
   9  *
  10  *      Based on linux/net/ipv4/ip_output.c
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  *
  17  *      Changes:
  18  *      A.N.Kuznetsov   :       airthmetics in fragmentation.
  19  *                              extension headers are implemented.
  20  *                              route changes now work.
  21  *                              ip6_forward does not confuse sniffers.
  22  *                              etc.
  23  *
  24  *      H. von Brand    :       Added missing #include <linux/string.h>
  25  *      Imran Patel     :       frag id should be in NBO
  26  *      Kazunori MIYAZAWA @USAGI
  27  *                      :       add ip6_append_data and related functions
  28  *                              for datagram xmit
  29  */
  30
  31 #include <linux/errno.h>
  32 #include <linux/types.h>
  33 #include <linux/string.h>
  34 #include <linux/socket.h>
  35 #include <linux/net.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/in6.h>
  39 #include <linux/tcp.h>
  40 #include <linux/route.h>
  41 #include <linux/module.h>
  42
  43 #include <linux/netfilter.h>
  44 #include <linux/netfilter_ipv6.h>
  45
  46 #include <net/sock.h>
  47 #include <net/snmp.h>
  48
  49 #include <net/ipv6.h>
  50 #include <net/ndisc.h>
  51 #include <net/protocol.h>
  52 #include <net/ip6_route.h>
  53 #include <net/addrconf.h>
  54 #include <net/rawv6.h>
  55 #include <net/icmp.h>
  56 #include <net/xfrm.h>
  57 #include <net/checksum.h>
  58
  59 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
  60
  61 static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr)
  62 {
  63         static u32 ipv6_fragmentation_id = 1;
  64         static DEFINE_SPINLOCK(ip6_id_lock);
  65
  66         spin_lock_bh(&ip6_id_lock);
  67         fhdr->identification = htonl(ipv6_fragmentation_id);
  68         if (++ipv6_fragmentation_id == 0)
  69                 ipv6_fragmentation_id = 1;
  70         spin_unlock_bh(&ip6_id_lock);
  71 }
  72
  73 static inline int ip6_output_finish(struct sk_buff *skb)
  74 {
  75         struct dst_entry *dst = skb->dst;
  76
  77         if (dst->hh)
  78                 return neigh_hh_output(dst->hh, skb);
  79         else if (dst->neighbour)
  80                 return dst->neighbour->output(skb);
  81
  82         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
  83         kfree_skb(skb);
  84         return -EINVAL;
  85
  86 }
  87
  88 /* dev_loopback_xmit for use with netfilter. */
  89 static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
  90 {
  91         skb_reset_mac_header(newskb);
  92         __skb_pull(newskb, skb_network_offset(newskb));
  93         newskb->pkt_type = PACKET_LOOPBACK;
  94         newskb->ip_summed = CHECKSUM_UNNECESSARY;
  95         BUG_TRAP(newskb->dst);
  96
  97         netif_rx(newskb);
  98         return 0;
  99 }
 100
 101
 102 static int ip6_output2(struct sk_buff *skb)
 103 {
 104         struct dst_entry *dst = skb->dst;
 105         struct net_device *dev = dst->dev;
 106
 107         skb->protocol = htons(ETH_P_IPV6);
 108         skb->dev = dev;
 109
 110         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
 111                 struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;
 112                 struct inet6_dev *idev = ip6_dst_idev(skb->dst);
 113
 114                 if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
 115                     ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
 116                                         &ipv6_hdr(skb)->saddr)) {
 117                         struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
 118
 119                         /* Do not check for IFF_ALLMULTI; multicast routing
 120                            is not supported in any case.
 121                          */
 122                         if (newskb)
 123                                 NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL,
 124                                         newskb->dev,
 125                                         ip6_dev_loopback_xmit);
 126
 127                         if (ipv6_hdr(skb)->hop_limit == 0) {
 128                                 IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS);
 129                                 kfree_skb(skb);
 130                                 return 0;
 131                         }
 132                 }
 133
 134                 IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS);
 135         }
 136
 137         return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish);
 138 }
 139
 140 int ip6_output(struct sk_buff *skb)
 141 {
 142         if ((skb->len > dst_mtu(skb->dst) && !skb_is_gso(skb)) ||
 143                                 dst_allfrag(skb->dst))
 144                 return ip6_fragment(skb, ip6_output2);
 145         else
 146                 return ip6_output2(skb);
 147 }
 148
 149 /*
 150  *      xmit an sk_buff (used by TCP)
 151  */
 152
 153 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 154              struct ipv6_txoptions *opt, int ipfragok)
 155 {
 156         struct ipv6_pinfo *np = inet6_sk(sk);
 157         struct in6_addr *first_hop = &fl->fl6_dst;
 158         struct dst_entry *dst = skb->dst;
 159         struct ipv6hdr *hdr;
 160         u8  proto = fl->proto;
 161         int seg_len = skb->len;
 162         int hlimit, tclass;
 163         u32 mtu;
 164
 165         if (opt) {
 166                 int head_room;
 167
 168                 /* First: exthdrs may take lots of space (~8K for now)
 169                    MAX_HEADER is not enough.
 170                  */
 171                 head_room = opt->opt_nflen + opt->opt_flen;
 172                 seg_len += head_room;
 173                 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
 174
 175                 if (skb_headroom(skb) < head_room) {
 176                         struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
 177                         if (skb2 == NULL) {
 178                                 IP6_INC_STATS(ip6_dst_idev(skb->dst),
 179                                               IPSTATS_MIB_OUTDISCARDS);
 180                                 kfree_skb(skb);
 181                                 return -ENOBUFS;
 182                         }
 183                         kfree_skb(skb);
 184                         skb = skb2;
 185                         if (sk)
 186                                 skb_set_owner_w(skb, sk);
 187                 }
 188                 if (opt->opt_flen)
 189                         ipv6_push_frag_opts(skb, opt, &proto);
 190                 if (opt->opt_nflen)
 191                         ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
 192         }
 193
 194         skb_push(skb, sizeof(struct ipv6hdr));
 195         skb_reset_network_header(skb);
 196         hdr = ipv6_hdr(skb);
 197
 198         /*
 199          *      Fill in the IPv6 header
 200          */
 201
 202         hlimit = -1;
 203         if (np)
 204                 hlimit = np->hop_limit;
 205         if (hlimit < 0)
 206                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 207         if (hlimit < 0)
 208                 hlimit = ipv6_get_hoplimit(dst->dev);
 209
 210         tclass = -1;
 211         if (np)
 212                 tclass = np->tclass;
 213         if (tclass < 0)
 214                 tclass = 0;
 215
 216         *(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;
 217
 218         hdr->payload_len = htons(seg_len);
 219         hdr->nexthdr = proto;
 220         hdr->hop_limit = hlimit;
 221
 222         ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
 223         ipv6_addr_copy(&hdr->daddr, first_hop);
 224
 225         skb->priority = sk->sk_priority;
 226
 227         mtu = dst_mtu(dst);
 228         if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
 229                 IP6_INC_STATS(ip6_dst_idev(skb->dst),
 230                               IPSTATS_MIB_OUTREQUESTS);
 231                 return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
 232                                 dst_output);
 233         }
 234
 235         if (net_ratelimit())
 236                 printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
 237         skb->dev = dst->dev;
 238         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
 239         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
 240         kfree_skb(skb);
 241         return -EMSGSIZE;
 242 }
 243
 244 EXPORT_SYMBOL(ip6_xmit);
 245
 246 /*
 247  *      To avoid extra problems ND packets are send through this
 248  *      routine. It's code duplication but I really want to avoid
 249  *      extra checks since ipv6_build_header is used by TCP (which
 250  *      is for us performance critical)
 251  */
 252
 253 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
 254                struct in6_addr *saddr, struct in6_addr *daddr,
 255                int proto, int len)
 256 {
 257         struct ipv6_pinfo *np = inet6_sk(sk);
 258         struct ipv6hdr *hdr;
 259         int totlen;
 260
 261         skb->protocol = htons(ETH_P_IPV6);
 262         skb->dev = dev;
 263
 264         totlen = len + sizeof(struct ipv6hdr);
 265
 266         skb_reset_network_header(skb);
 267         skb_put(skb, sizeof(struct ipv6hdr));
 268         hdr = ipv6_hdr(skb);
 269
 270         *(__be32*)hdr = htonl(0x60000000);
 271
 272         hdr->payload_len = htons(len);
 273         hdr->nexthdr = proto;
 274         hdr->hop_limit = np->hop_limit;
 275
 276         ipv6_addr_copy(&hdr->saddr, saddr);
 277         ipv6_addr_copy(&hdr->daddr, daddr);
 278
 279         return 0;
 280 }
 281
 282 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 283 {
 284         struct ip6_ra_chain *ra;
 285         struct sock *last = NULL;
 286
 287         read_lock(&ip6_ra_lock);
 288         for (ra = ip6_ra_chain; ra; ra = ra->next) {
 289                 struct sock *sk = ra->sk;
 290                 if (sk && ra->sel == sel &&
 291                     (!sk->sk_bound_dev_if ||
 292                      sk->sk_bound_dev_if == skb->dev->ifindex)) {
 293                         if (last) {
 294                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 295                                 if (skb2)
 296                                         rawv6_rcv(last, skb2);
 297                         }
 298                         last = sk;
 299                 }
 300         }
 301
 302         if (last) {
 303                 rawv6_rcv(last, skb);
 304                 read_unlock(&ip6_ra_lock);
 305                 return 1;
 306         }
 307         read_unlock(&ip6_ra_lock);
 308         return 0;
 309 }
 310
 311 static int ip6_forward_proxy_check(struct sk_buff *skb)
 312 {
 313         struct ipv6hdr *hdr = ipv6_hdr(skb);
 314         u8 nexthdr = hdr->nexthdr;
 315         int offset;
 316
 317         if (ipv6_ext_hdr(nexthdr)) {
 318                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
 319                 if (offset < 0)
 320                         return 0;
 321         } else
 322                 offset = sizeof(struct ipv6hdr);
 323
 324         if (nexthdr == IPPROTO_ICMPV6) {
 325                 struct icmp6hdr *icmp6;
 326
 327                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
 328                                          offset + 1 - skb->data)))
 329                         return 0;
 330
 331                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 332
 333                 switch (icmp6->icmp6_type) {
 334                 case NDISC_ROUTER_SOLICITATION:
 335                 case NDISC_ROUTER_ADVERTISEMENT:
 336                 case NDISC_NEIGHBOUR_SOLICITATION:
 337                 case NDISC_NEIGHBOUR_ADVERTISEMENT:
 338                 case NDISC_REDIRECT:
 339                         /* For reaction involving unicast neighbor discovery
 340                          * message destined to the proxied address, pass it to
 341                          * input function.
 342                          */
 343                         return 1;
 344                 default:
 345                         break;
 346                 }
 347         }
 348
 349         /*
 350          * The proxying router can't forward traffic sent to a link-local
 351          * address, so signal the sender and discard the packet. This
 352          * behavior is clarified by the MIPv6 specification.
 353          */
 354         if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
 355                 dst_link_failure(skb);
 356                 return -1;
 357         }
 358
 359         return 0;
 360 }
 361
 362 static inline int ip6_forward_finish(struct sk_buff *skb)
 363 {
 364         return dst_output(skb);
 365 }
 366
 367 int ip6_forward(struct sk_buff *skb)
 368 {
 369         struct dst_entry *dst = skb->dst;
 370         struct ipv6hdr *hdr = ipv6_hdr(skb);
 371         struct inet6_skb_parm *opt = IP6CB(skb);
 372
 373         if (ipv6_devconf.forwarding == 0)
 374                 goto error;
 375
 376         if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 377                 IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 378                 goto drop;
 379         }
 380
 381         skb_forward_csum(skb);
 382
 383         /*
 384          *      We DO NOT make any processing on
 385          *      RA packets, pushing them to user level AS IS
 386          *      without ane WARRANTY that application will be able
 387          *      to interpret them. The reason is that we
 388          *      cannot make anything clever here.
 389          *
 390          *      We are not end-node, so that if packet contains
 391          *      AH/ESP, we cannot make anything.
 392          *      Defragmentation also would be mistake, RA packets
 393          *      cannot be fragmented, because there is no warranty
 394          *      that different fragments will go along one path. --ANK
 395          */
 396         if (opt->ra) {
 397                 u8 *ptr = skb_network_header(skb) + opt->ra;
 398                 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
 399                         return 0;
 400         }
 401
 402         /*
 403          *      check and decrement ttl
 404          */
 405         if (hdr->hop_limit <= 1) {
 406                 /* Force OUTPUT device used as source address */
 407                 skb->dev = dst->dev;
 408                 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 409                             0, skb->dev);
 410                 IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 411
 412                 kfree_skb(skb);
 413                 return -ETIMEDOUT;
 414         }
 415
 416         /* XXX: idev->cnf.proxy_ndp? */
 417         if (ipv6_devconf.proxy_ndp &&
 418             pneigh_lookup(&nd_tbl, &hdr->daddr, skb->dev, 0)) {
 419                 int proxied = ip6_forward_proxy_check(skb);
 420                 if (proxied > 0)
 421                         return ip6_input(skb);
 422                 else if (proxied < 0) {
 423                         IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 424                         goto drop;
 425                 }
 426         }
 427
 428         if (!xfrm6_route_forward(skb)) {
 429                 IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
 430                 goto drop;
 431         }
 432         dst = skb->dst;
 433
 434         /* IPv6 specs say nothing about it, but it is clear that we cannot
 435            send redirects to source routed frames.
 436          */
 437         if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
 438                 struct in6_addr *target = NULL;
 439                 struct rt6_info *rt;
 440                 struct neighbour *n = dst->neighbour;
 441
 442                 /*
 443                  *      incoming and outgoing devices are the same
 444                  *      send a redirect.
 445                  */
 446
 447                 rt = (struct rt6_info *) dst;
 448                 if ((rt->rt6i_flags & RTF_GATEWAY))
 449                         target = (struct in6_addr*)&n->primary_key;
 450                 else
 451                         target = &hdr->daddr;
 452
 453                 /* Limit redirects both by destination (here)
 454                    and by source (inside ndisc_send_redirect)
 455                  */
 456                 if (xrlim_allow(dst, 1*HZ))
 457                         ndisc_send_redirect(skb, n, target);
 458         } else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK
 459                                                 |IPV6_ADDR_LINKLOCAL)) {
 460                 /* This check is security critical. */
 461                 goto error;
 462         }
 463
 464         if (skb->len > dst_mtu(dst)) {
 465                 /* Again, force OUTPUT device used as source address */
 466                 skb->dev = dst->dev;
 467                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
 468                 IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
 469                 IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
 470                 kfree_skb(skb);
 471                 return -EMSGSIZE;
 472         }
 473
 474         if (skb_cow(skb, dst->dev->hard_header_len)) {
 475                 IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
 476                 goto drop;
 477         }
 478
 479         hdr = ipv6_hdr(skb);
 480
 481         /* Mangling hops number delayed to point after skb COW */
 482
 483         hdr->hop_limit--;
 484
 485         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 486         return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish);
 487
 488 error:
 489         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
 490 drop:
 491         kfree_skb(skb);
 492         return -EINVAL;
 493 }
 494
 495 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 496 {
 497         to->pkt_type = from->pkt_type;
 498         to->priority = from->priority;
 499         to->protocol = from->protocol;
 500         dst_release(to->dst);
 501         to->dst = dst_clone(from->dst);
 502         to->dev = from->dev;
 503         to->mark = from->mark;
 504
 505 #ifdef CONFIG_NET_SCHED
 506         to->tc_index = from->tc_index;
 507 #endif
 508         nf_copy(to, from);
 509         skb_copy_secmark(to, from);
 510 }
 511
 512 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 513 {
 514         u16 offset = sizeof(struct ipv6hdr);
 515         struct ipv6_opt_hdr *exthdr =
 516                                 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
 517         unsigned int packet_len = skb->tail - skb->network_header;
 518         int found_rhdr = 0;
 519         *nexthdr = &ipv6_hdr(skb)->nexthdr;
 520
 521         while (offset + 1 <= packet_len) {
 522
 523                 switch (**nexthdr) {
 524
 525                 case NEXTHDR_HOP:
 526                         break;
 527                 case NEXTHDR_ROUTING:
 528                         found_rhdr = 1;
 529                         break;
 530                 case NEXTHDR_DEST:
 531 #ifdef CONFIG_IPV6_MIP6
 532                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
 533                                 break;
 534 #endif
 535                         if (found_rhdr)
 536                                 return offset;
 537                         break;
 538                 default :
 539                         return offset;
 540                 }
 541
 542                 offset += ipv6_optlen(exthdr);
 543                 *nexthdr = &exthdr->nexthdr;
 544                 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
 545                                                  offset);
 546         }
 547
 548         return offset;
 549 }
 550 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
 551
 552 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 553 {
 554         struct net_device *dev;
 555         struct sk_buff *frag;
 556         struct rt6_info *rt = (struct rt6_info*)skb->dst;
 557         struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
 558         struct ipv6hdr *tmp_hdr;
 559         struct frag_hdr *fh;
 560         unsigned int mtu, hlen, left, len;
 561         __be32 frag_id = 0;
 562         int ptr, offset = 0, err=0;
 563         u8 *prevhdr, nexthdr = 0;
 564
 565         dev = rt->u.dst.dev;
 566         hlen = ip6_find_1stfragopt(skb, &prevhdr);
 567         nexthdr = *prevhdr;
 568
 569         mtu = dst_mtu(&rt->u.dst);
 570         if (np && np->frag_size < mtu) {
 571                 if (np->frag_size)
 572                         mtu = np->frag_size;
 573         }
 574         mtu -= hlen + sizeof(struct frag_hdr);
 575
 576         if (skb_shinfo(skb)->frag_list) {
 577                 int first_len = skb_pagelen(skb);
 578
 579                 if (first_len - hlen > mtu ||
 580                     ((first_len - hlen) & 7) ||
 581                     skb_cloned(skb))
 582                         goto slow_path;
 583
 584                 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
 585                         /* Correct geometry. */
 586                         if (frag->len > mtu ||
 587                             ((frag->len & 7) && frag->next) ||
 588                             skb_headroom(frag) < hlen)
 589                             goto slow_path;
 590
 591                         /* Partially cloned skb? */
 592                         if (skb_shared(frag))
 593                                 goto slow_path;
 594
 595                         BUG_ON(frag->sk);
 596                         if (skb->sk) {
 597                                 sock_hold(skb->sk);
 598                                 frag->sk = skb->sk;
 599                                 frag->destructor = sock_wfree;
 600                                 skb->truesize -= frag->truesize;
 601                         }
 602                 }
 603
 604                 err = 0;
 605                 offset = 0;
 606                 frag = skb_shinfo(skb)->frag_list;
 607                 skb_shinfo(skb)->frag_list = NULL;
 608                 /* BUILD HEADER */
 609
 610                 *prevhdr = NEXTHDR_FRAGMENT;
 611                 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 612                 if (!tmp_hdr) {
 613                         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
 614                         return -ENOMEM;
 615                 }
 616
 617                 __skb_pull(skb, hlen);
 618                 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
 619                 __skb_push(skb, hlen);
 620                 skb_reset_network_header(skb);
 621                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 622
 623                 ipv6_select_ident(skb, fh);
 624                 fh->nexthdr = nexthdr;
 625                 fh->reserved = 0;
 626                 fh->frag_off = htons(IP6_MF);
 627                 frag_id = fh->identification;
 628
 629                 first_len = skb_pagelen(skb);
 630                 skb->data_len = first_len - skb_headlen(skb);
 631                 skb->len = first_len;
 632                 ipv6_hdr(skb)->payload_len = htons(first_len -
 633                                                    sizeof(struct ipv6hdr));
 634
 635                 dst_hold(&rt->u.dst);
 636
 637                 for (;;) {
 638                         /* Prepare header of the next frame,
 639                          * before previous one went down. */
 640                         if (frag) {
 641                                 frag->ip_summed = CHECKSUM_NONE;
 642                                 skb_reset_transport_header(frag);
 643                                 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 644                                 __skb_push(frag, hlen);
 645                                 skb_reset_network_header(frag);
 646                                 memcpy(skb_network_header(frag), tmp_hdr,
 647                                        hlen);
 648                                 offset += skb->len - hlen - sizeof(struct frag_hdr);
 649                                 fh->nexthdr = nexthdr;
 650                                 fh->reserved = 0;
 651                                 fh->frag_off = htons(offset);
 652                                 if (frag->next != NULL)
 653                                         fh->frag_off |= htons(IP6_MF);
 654                                 fh->identification = frag_id;
 655                                 ipv6_hdr(frag)->payload_len =
 656                                                 htons(frag->len -
 657                                                       sizeof(struct ipv6hdr));
 658                                 ip6_copy_metadata(frag, skb);
 659                         }
 660
 661                         err = output(skb);
 662                         if(!err)
 663                                 IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGCREATES);
 664
 665                         if (err || !frag)
 666                                 break;
 667
 668                         skb = frag;
 669                         frag = skb->next;
 670                         skb->next = NULL;
 671                 }
 672
 673                 kfree(tmp_hdr);
 674
 675                 if (err == 0) {
 676                         IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGOKS);
 677                         dst_release(&rt->u.dst);
 678                         return 0;
 679                 }
 680
 681                 while (frag) {
 682                         skb = frag->next;
 683                         kfree_skb(frag);
 684                         frag = skb;
 685                 }
 686
 687                 IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGFAILS);
 688                 dst_release(&rt->u.dst);
 689                 return err;
 690         }
 691
 692 slow_path:
 693         left = skb->len - hlen;         /* Space per frame */
 694         ptr = hlen;                     /* Where to start from */
 695
 696         /*
 697          *      Fragment the datagram.
 698          */
 699
 700         *prevhdr = NEXTHDR_FRAGMENT;
 701
 702         /*
 703          *      Keep copying data until we run out.
 704          */
 705         while(left > 0) {
 706                 len = left;
 707                 /* IF: it doesn't fit, use 'mtu' - the data space left */
 708                 if (len > mtu)
 709                         len = mtu;
 710                 /* IF: we are not sending upto and including the packet end
 711                    then align the next start on an eight byte boundary */
 712                 if (len < left) {
 713                         len &= ~7;
 714                 }
 715                 /*
 716                  *      Allocate buffer.
 717                  */
 718
 719                 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
 720                         NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 721                         IP6_INC_STATS(ip6_dst_idev(skb->dst),
 722                                       IPSTATS_MIB_FRAGFAILS);
 723                         err = -ENOMEM;
 724                         goto fail;
 725                 }
 726
 727                 /*
 728                  *      Set up data on packet
 729                  */
 730
 731                 ip6_copy_metadata(frag, skb);
 732                 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
 733                 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 734                 skb_reset_network_header(frag);
 735                 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
 736                 frag->transport_header = (frag->network_header + hlen +
 737                                           sizeof(struct frag_hdr));
 738
 739                 /*
 740                  *      Charge the memory for the fragment to any owner
 741                  *      it might possess
 742                  */
 743                 if (skb->sk)
 744                         skb_set_owner_w(frag, skb->sk);
 745
 746                 /*
 747                  *      Copy the packet header into the new buffer.
 748                  */
 749                 memcpy(skb_network_header(frag), skb->data, hlen);
 750
 751                 /*
 752                  *      Build fragment header.
 753                  */
 754                 fh->nexthdr = nexthdr;
 755                 fh->reserved = 0;
 756                 if (!frag_id) {
 757                         ipv6_select_ident(skb, fh);
 758                         frag_id = fh->identification;
 759                 } else
 760                         fh->identification = frag_id;
 761
 762                 /*
 763                  *      Copy a block of the IP datagram.
 764                  */
 765                 if (skb_copy_bits(skb, ptr, skb_transport_header(skb), len))
 766                         BUG();
 767                 left -= len;
 768
 769                 fh->frag_off = htons(offset);
 770                 if (left > 0)
 771                         fh->frag_off |= htons(IP6_MF);
 772                 ipv6_hdr(frag)->payload_len = htons(frag->len -
 773                                                     sizeof(struct ipv6hdr));
 774
 775                 ptr += len;
 776                 offset += len;
 777
 778                 /*
 779                  *      Put this fragment into the sending queue.
 780                  */
 781                 err = output(frag);
 782                 if (err)
 783                         goto fail;
 784
 785                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGCREATES);
 786         }
 787         IP6_INC_STATS(ip6_dst_idev(skb->dst),
 788                       IPSTATS_MIB_FRAGOKS);
 789         kfree_skb(skb);
 790         return err;
 791
 792 fail:
 793         IP6_INC_STATS(ip6_dst_idev(skb->dst),
 794                       IPSTATS_MIB_FRAGFAILS);
 795         kfree_skb(skb);
 796         return err;
 797 }
 798
 799 static inline int ip6_rt_check(struct rt6key *rt_key,
 800                                struct in6_addr *fl_addr,
 801                                struct in6_addr *addr_cache)
 802 {
 803         return ((rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
 804                 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)));
 805 }
 806
 807 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 808                                           struct dst_entry *dst,
 809                                           struct flowi *fl)
 810 {
 811         struct ipv6_pinfo *np = inet6_sk(sk);
 812         struct rt6_info *rt = (struct rt6_info *)dst;
 813
 814         if (!dst)
 815                 goto out;
 816
 817         /* Yes, checking route validity in not connected
 818          * case is not very simple. Take into account,
 819          * that we do not support routing by source, TOS,
 820          * and MSG_DONTROUTE            --ANK (980726)
 821          *
 822          * 1. ip6_rt_check(): If route was host route,
 823          *    check that cached destination is current.
 824          *    If it is network route, we still may
 825          *    check its validity using saved pointer
 826          *    to the last used address: daddr_cache.
 827          *    We do not want to save whole address now,
 828          *    (because main consumer of this service
 829          *    is tcp, which has not this problem),
 830          *    so that the last trick works only on connected
 831          *    sockets.
 832          * 2. oif also should be the same.
 833          */
 834         if (ip6_rt_check(&rt->rt6i_dst, &fl->fl6_dst, np->daddr_cache) ||
 835 #ifdef CONFIG_IPV6_SUBTREES
 836             ip6_rt_check(&rt->rt6i_src, &fl->fl6_src, np->saddr_cache) ||
 837 #endif
 838             (fl->oif && fl->oif != dst->dev->ifindex)) {
 839                 dst_release(dst);
 840                 dst = NULL;
 841         }
 842
 843 out:
 844         return dst;
 845 }
 846
 847 static int ip6_dst_lookup_tail(struct sock *sk,
 848                                struct dst_entry **dst, struct flowi *fl)
 849 {
 850         int err;
 851
 852         if (*dst == NULL)
 853                 *dst = ip6_route_output(sk, fl);
 854
 855         if ((err = (*dst)->error))
 856                 goto out_err_release;
 857
 858         if (ipv6_addr_any(&fl->fl6_src)) {
 859                 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);
 860                 if (err)
 861                         goto out_err_release;
 862         }
 863
 864 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 865                 /*
 866                  * Here if the dst entry we've looked up
 867                  * has a neighbour entry that is in the INCOMPLETE
 868                  * state and the src address from the flow is
 869                  * marked as OPTIMISTIC, we release the found
 870                  * dst entry and replace it instead with the
 871                  * dst entry of the nexthop router
 872                  */
 873                 if (!((*dst)->neighbour->nud_state & NUD_VALID)) {
 874                         struct inet6_ifaddr *ifp;
 875                         struct flowi fl_gw;
 876                         int redirect;
 877
 878                         ifp = ipv6_get_ifaddr(&fl->fl6_src, (*dst)->dev, 1);
 879
 880                         redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
 881                         if (ifp)
 882                                 in6_ifa_put(ifp);
 883
 884                         if (redirect) {
 885                                 /*
 886                                  * We need to get the dst entry for the
 887                                  * default router instead
 888                                  */
 889                                 dst_release(*dst);
 890                                 memcpy(&fl_gw, fl, sizeof(struct flowi));
 891                                 memset(&fl_gw.fl6_dst, 0, sizeof(struct in6_addr));
 892                                 *dst = ip6_route_output(sk, &fl_gw);
 893                                 if ((err = (*dst)->error))
 894                                         goto out_err_release;
 895                         }
 896                 }
 897 #endif
 898
 899         return 0;
 900
 901 out_err_release:
 902         dst_release(*dst);
 903         *dst = NULL;
 904         return err;
 905 }
 906
 907 /**
 908  *      ip6_dst_lookup - perform route lookup on flow
 909  *      @sk: socket which provides route info
 910  *      @dst: pointer to dst_entry * for result
 911  *      @fl: flow to lookup
 912  *
 913  *      This function performs a route lookup on the given flow.
 914  *
 915  *      It returns zero on success, or a standard errno code on error.
 916  */
 917 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
 918 {
 919         *dst = NULL;
 920         return ip6_dst_lookup_tail(sk, dst, fl);
 921 }
 922 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 923
 924 /**
 925  *      ip6_sk_dst_lookup - perform socket cached route lookup on flow
 926  *      @sk: socket which provides the dst cache and route info
 927  *      @dst: pointer to dst_entry * for result
 928  *      @fl: flow to lookup
 929  *
 930  *      This function performs a route lookup on the given flow with the
 931  *      possibility of using the cached route in the socket if it is valid.
 932  *      It will take the socket dst lock when operating on the dst cache.
 933  *      As a result, this function can only be used in process context.
 934  *
 935  *      It returns zero on success, or a standard errno code on error.
 936  */
 937 int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
 938 {
 939         *dst = NULL;
 940         if (sk) {
 941                 *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
 942                 *dst = ip6_sk_dst_check(sk, *dst, fl);
 943         }
 944
 945         return ip6_dst_lookup_tail(sk, dst, fl);
 946 }
 947 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup);
 948
 949 static inline int ip6_ufo_append_data(struct sock *sk,
 950                         int getfrag(void *from, char *to, int offset, int len,
 951                         int odd, struct sk_buff *skb),
 952                         void *from, int length, int hh_len, int fragheaderlen,
 953                         int transhdrlen, int mtu,unsigned int flags)
 954
 955 {
 956         struct sk_buff *skb;
 957         int err;
 958
 959         /* There is support for UDP large send offload by network
 960          * device, so create one single skb packet containing complete
 961          * udp datagram
 962          */
 963         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
 964                 skb = sock_alloc_send_skb(sk,
 965                         hh_len + fragheaderlen + transhdrlen + 20,
 966                         (flags & MSG_DONTWAIT), &err);
 967                 if (skb == NULL)
 968                         return -ENOMEM;
 969
 970                 /* reserve space for Hardware header */
 971                 skb_reserve(skb, hh_len);
 972
 973                 /* create space for UDP/IP header */
 974                 skb_put(skb,fragheaderlen + transhdrlen);
 975
 976                 /* initialize network header pointer */
 977                 skb_reset_network_header(skb);
 978
 979                 /* initialize protocol header pointer */
 980                 skb->transport_header = skb->network_header + fragheaderlen;
 981
 982                 skb->ip_summed = CHECKSUM_PARTIAL;
 983                 skb->csum = 0;
 984                 sk->sk_sndmsg_off = 0;
 985         }
 986
 987         err = skb_append_datato_frags(sk,skb, getfrag, from,
 988                                       (length - transhdrlen));
 989         if (!err) {
 990                 struct frag_hdr fhdr;
 991
 992                 /* specify the length of each IP datagram fragment*/
 993                 skb_shinfo(skb)->gso_size = mtu - fragheaderlen -
 994                                             sizeof(struct frag_hdr);
 995                 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 996                 ipv6_select_ident(skb, &fhdr);
 997                 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
 998                 __skb_queue_tail(&sk->sk_write_queue, skb);
 999
1000                 return 0;
1001         }
1002         /* There is not enough support do UPD LSO,
1003          * so follow normal path
1004          */
1005         kfree_skb(skb);
1006
1007         return err;
1008 }
1009
1010 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1011         int offset, int len, int odd, struct sk_buff *skb),
1012         void *from, int length, int transhdrlen,
1013         int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
1014         struct rt6_info *rt, unsigned int flags)
1015 {
1016         struct inet_sock *inet = inet_sk(sk);
1017         struct ipv6_pinfo *np = inet6_sk(sk);
1018         struct sk_buff *skb;
1019         unsigned int maxfraglen, fragheaderlen;
1020         int exthdrlen;
1021         int hh_len;
1022         int mtu;
1023         int copy;
1024         int err;
1025         int offset = 0;
1026         int csummode = CHECKSUM_NONE;
1027
1028         if (flags&MSG_PROBE)
1029                 return 0;
1030         if (skb_queue_empty(&sk->sk_write_queue)) {
1031                 /*
1032                  * setup for corking
1033                  */
1034                 if (opt) {
1035                         if (np->cork.opt == NULL) {
1036                                 np->cork.opt = kmalloc(opt->tot_len,
1037                                                        sk->sk_allocation);
1038                                 if (unlikely(np->cork.opt == NULL))
1039                                         return -ENOBUFS;
1040                         } else if (np->cork.opt->tot_len < opt->tot_len) {
1041                                 printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
1042                                 return -EINVAL;
1043                         }
1044                         memcpy(np->cork.opt, opt, opt->tot_len);
1045                         inet->cork.flags |= IPCORK_OPT;
1046                         /* need source address above miyazawa*/
1047                 }
1048                 dst_hold(&rt->u.dst);
1049                 np->cork.rt = rt;
1050                 inet->cork.fl = *fl;
1051                 np->cork.hop_limit = hlimit;
1052                 np->cork.tclass = tclass;
1053                 mtu = dst_mtu(rt->u.dst.path);
1054                 if (np->frag_size < mtu) {
1055                         if (np->frag_size)
1056                                 mtu = np->frag_size;
1057                 }
1058                 inet->cork.fragsize = mtu;
1059                 if (dst_allfrag(rt->u.dst.path))
1060                         inet->cork.flags |= IPCORK_ALLFRAG;
1061                 inet->cork.length = 0;
1062                 sk->sk_sndmsg_page = NULL;
1063                 sk->sk_sndmsg_off = 0;
1064                 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0);
1065                 length += exthdrlen;
1066                 transhdrlen += exthdrlen;
1067         } else {
1068                 rt = np->cork.rt;
1069                 fl = &inet->cork.fl;
1070                 if (inet->cork.flags & IPCORK_OPT)
1071                         opt = np->cork.opt;
1072                 transhdrlen = 0;
1073                 exthdrlen = 0;
1074                 mtu = inet->cork.fragsize;
1075         }
1076
1077         hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
1078
1079         fragheaderlen = sizeof(struct ipv6hdr) + rt->u.dst.nfheader_len + (opt ? opt->opt_nflen : 0);
1080         maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1081
1082         if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1083                 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1084                         ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
1085                         return -EMSGSIZE;
1086                 }
1087         }
1088
1089         /*
1090          * Let's try using as much space as possible.
1091          * Use MTU if total length of the message fits into the MTU.
1092          * Otherwise, we need to reserve fragment header and
1093          * fragment alignment (= 8-15 octects, in total).
1094          *
1095          * Note that we may need to "move" the data from the tail of
1096          * of the buffer to the new fragment when we split
1097          * the message.
1098          *
1099          * FIXME: It may be fragmented into multiple chunks
1100          *        at once if non-fragmentable extension headers
1101          *        are too large.
1102          * --yoshfuji
1103          */
1104
1105         inet->cork.length += length;
1106         if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
1107             (rt->u.dst.dev->features & NETIF_F_UFO)) {
1108
1109                 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
1110                                           fragheaderlen, transhdrlen, mtu,
1111                                           flags);
1112                 if (err)
1113                         goto error;
1114                 return 0;
1115         }
1116
1117         if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1118                 goto alloc_new_skb;
1119
1120         while (length > 0) {
1121                 /* Check if the remaining data fits into current packet. */
1122                 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1123                 if (copy < length)
1124                         copy = maxfraglen - skb->len;
1125
1126                 if (copy <= 0) {
1127                         char *data;
1128                         unsigned int datalen;
1129                         unsigned int fraglen;
1130                         unsigned int fraggap;
1131                         unsigned int alloclen;
1132                         struct sk_buff *skb_prev;
1133 alloc_new_skb:
1134                         skb_prev = skb;
1135
1136                         /* There's no room in the current skb */
1137                         if (skb_prev)
1138                                 fraggap = skb_prev->len - maxfraglen;
1139                         else
1140                                 fraggap = 0;
1141
1142                         /*
1143                          * If remaining data exceeds the mtu,
1144                          * we know we need more fragment(s).
1145                          */
1146                         datalen = length + fraggap;
1147                         if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1148                                 datalen = maxfraglen - fragheaderlen;
1149
1150                         fraglen = datalen + fragheaderlen;
1151                         if ((flags & MSG_MORE) &&
1152                             !(rt->u.dst.dev->features&NETIF_F_SG))
1153                                 alloclen = mtu;
1154                         else
1155                                 alloclen = datalen + fragheaderlen;
1156
1157                         /*
1158                          * The last fragment gets additional space at tail.
1159                          * Note: we overallocate on fragments with MSG_MODE
1160                          * because we have no idea if we're the last one.
1161                          */
1162                         if (datalen == length + fraggap)
1163                                 alloclen += rt->u.dst.trailer_len;
1164
1165                         /*
1166                          * We just reserve space for fragment header.
1167                          * Note: this may be overallocation if the message
1168                          * (without MSG_MORE) fits into the MTU.
1169                          */
1170                         alloclen += sizeof(struct frag_hdr);
1171
1172                         if (transhdrlen) {
1173                                 skb = sock_alloc_send_skb(sk,
1174                                                 alloclen + hh_len,
1175                                                 (flags & MSG_DONTWAIT), &err);
1176                         } else {
1177                                 skb = NULL;
1178                                 if (atomic_read(&sk->sk_wmem_alloc) <=
1179                                     2 * sk->sk_sndbuf)
1180                                         skb = sock_wmalloc(sk,
1181                                                            alloclen + hh_len, 1,
1182                                                            sk->sk_allocation);
1183                                 if (unlikely(skb == NULL))
1184                                         err = -ENOBUFS;
1185                         }
1186                         if (skb == NULL)
1187                                 goto error;
1188                         /*
1189                          *      Fill in the control structures
1190                          */
1191                         skb->ip_summed = csummode;
1192                         skb->csum = 0;
1193                         /* reserve for fragmentation */
1194                         skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
1195
1196                         /*
1197                          *      Find where to start putting bytes
1198                          */
1199                         data = skb_put(skb, fraglen);
1200                         skb_set_network_header(skb, exthdrlen);
1201                         data += fragheaderlen;
1202                         skb->transport_header = (skb->network_header +
1203                                                  fragheaderlen);
1204                         if (fraggap) {
1205                                 skb->csum = skb_copy_and_csum_bits(
1206                                         skb_prev, maxfraglen,
1207                                         data + transhdrlen, fraggap, 0);
1208                                 skb_prev->csum = csum_sub(skb_prev->csum,
1209                                                           skb->csum);
1210                                 data += fraggap;
1211                                 pskb_trim_unique(skb_prev, maxfraglen);
1212                         }
1213                         copy = datalen - transhdrlen - fraggap;
1214                         if (copy < 0) {
1215                                 err = -EINVAL;
1216                                 kfree_skb(skb);
1217                                 goto error;
1218                         } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1219                                 err = -EFAULT;
1220                                 kfree_skb(skb);
1221                                 goto error;
1222                         }
1223
1224                         offset += copy;
1225                         length -= datalen - fraggap;
1226                         transhdrlen = 0;
1227                         exthdrlen = 0;
1228                         csummode = CHECKSUM_NONE;
1229
1230                         /*
1231                          * Put the packet on the pending queue
1232                          */
1233                         __skb_queue_tail(&sk->sk_write_queue, skb);
1234                         continue;
1235                 }
1236
1237                 if (copy > length)
1238                         copy = length;
1239
1240                 if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
1241                         unsigned int off;
1242
1243                         off = skb->len;
1244                         if (getfrag(from, skb_put(skb, copy),
1245                                                 offset, copy, off, skb) < 0) {
1246                                 __skb_trim(skb, off);
1247                                 err = -EFAULT;
1248                                 goto error;
1249                         }
1250                 } else {
1251                         int i = skb_shinfo(skb)->nr_frags;
1252                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1253                         struct page *page = sk->sk_sndmsg_page;
1254                         int off = sk->sk_sndmsg_off;
1255                         unsigned int left;
1256
1257                         if (page && (left = PAGE_SIZE - off) > 0) {
1258                                 if (copy >= left)
1259                                         copy = left;
1260                                 if (page != frag->page) {
1261                                         if (i == MAX_SKB_FRAGS) {
1262                                                 err = -EMSGSIZE;
1263                                                 goto error;
1264                                         }
1265                                         get_page(page);
1266                                         skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1267                                         frag = &skb_shinfo(skb)->frags[i];
1268                                 }
1269                         } else if(i < MAX_SKB_FRAGS) {
1270                                 if (copy > PAGE_SIZE)
1271                                         copy = PAGE_SIZE;
1272                                 page = alloc_pages(sk->sk_allocation, 0);
1273                                 if (page == NULL) {
1274                                         err = -ENOMEM;
1275                                         goto error;
1276                                 }
1277                                 sk->sk_sndmsg_page = page;
1278                                 sk->sk_sndmsg_off = 0;
1279
1280                                 skb_fill_page_desc(skb, i, page, 0, 0);
1281                                 frag = &skb_shinfo(skb)->frags[i];
1282                                 skb->truesize += PAGE_SIZE;
1283                                 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
1284                         } else {
1285                                 err = -EMSGSIZE;
1286                                 goto error;
1287                         }
1288                         if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1289                                 err = -EFAULT;
1290                                 goto error;
1291                         }
1292                         sk->sk_sndmsg_off += copy;
1293                         frag->size += copy;
1294                         skb->len += copy;
1295                         skb->data_len += copy;
1296                 }
1297                 offset += copy;
1298                 length -= copy;
1299         }
1300         return 0;
1301 error:
1302         inet->cork.length -= length;
1303         IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1304         return err;
1305 }
1306
1307 int ip6_push_pending_frames(struct sock *sk)
1308 {
1309         struct sk_buff *skb, *tmp_skb;
1310         struct sk_buff **tail_skb;
1311         struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1312         struct inet_sock *inet = inet_sk(sk);
1313         struct ipv6_pinfo *np = inet6_sk(sk);
1314         struct ipv6hdr *hdr;
1315         struct ipv6_txoptions *opt = np->cork.opt;
1316         struct rt6_info *rt = np->cork.rt;
1317         struct flowi *fl = &inet->cork.fl;
1318         unsigned char proto = fl->proto;
1319         int err = 0;
1320
1321         if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1322                 goto out;
1323         tail_skb = &(skb_shinfo(skb)->frag_list);
1324
1325         /* move skb->data to ip header from ext header */
1326         if (skb->data < skb_network_header(skb))
1327                 __skb_pull(skb, skb_network_offset(skb));
1328         while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1329                 __skb_pull(tmp_skb, skb_network_header_len(skb));
1330                 *tail_skb = tmp_skb;
1331                 tail_skb = &(tmp_skb->next);
1332                 skb->len += tmp_skb->len;
1333                 skb->data_len += tmp_skb->len;
1334                 skb->truesize += tmp_skb->truesize;
1335                 __sock_put(tmp_skb->sk);
1336                 tmp_skb->destructor = NULL;
1337                 tmp_skb->sk = NULL;
1338         }
1339
1340         ipv6_addr_copy(final_dst, &fl->fl6_dst);
1341         __skb_pull(skb, skb_network_header_len(skb));
1342         if (opt && opt->opt_flen)
1343                 ipv6_push_frag_opts(skb, opt, &proto);
1344         if (opt && opt->opt_nflen)
1345                 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1346
1347         skb_push(skb, sizeof(struct ipv6hdr));
1348         skb_reset_network_header(skb);
1349         hdr = ipv6_hdr(skb);
1350
1351         *(__be32*)hdr = fl->fl6_flowlabel |
1352                      htonl(0x60000000 | ((int)np->cork.tclass << 20));
1353
1354         if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN)
1355                 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
1356         else
1357                 hdr->payload_len = 0;
1358         hdr->hop_limit = np->cork.hop_limit;
1359         hdr->nexthdr = proto;
1360         ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
1361         ipv6_addr_copy(&hdr->daddr, final_dst);
1362
1363         skb->priority = sk->sk_priority;
1364
1365         skb->dst = dst_clone(&rt->u.dst);
1366         IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
1367         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output);
1368         if (err) {
1369                 if (err > 0)
1370                         err = np->recverr ? net_xmit_errno(err) : 0;
1371                 if (err)
1372                         goto error;
1373         }
1374
1375 out:
1376         inet->cork.flags &= ~IPCORK_OPT;
1377         kfree(np->cork.opt);
1378         np->cork.opt = NULL;
1379         if (np->cork.rt) {
1380                 dst_release(&np->cork.rt->u.dst);
1381                 np->cork.rt = NULL;
1382                 inet->cork.flags &= ~IPCORK_ALLFRAG;
1383         }
1384         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1385         return err;
1386 error:
1387         goto out;
1388 }
1389
1390 void ip6_flush_pending_frames(struct sock *sk)
1391 {
1392         struct inet_sock *inet = inet_sk(sk);
1393         struct ipv6_pinfo *np = inet6_sk(sk);
1394         struct sk_buff *skb;
1395
1396         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1397                 IP6_INC_STATS(ip6_dst_idev(skb->dst),
1398                               IPSTATS_MIB_OUTDISCARDS);
1399                 kfree_skb(skb);
1400         }
1401
1402         inet->cork.flags &= ~IPCORK_OPT;
1403
1404         kfree(np->cork.opt);
1405         np->cork.opt = NULL;
1406         if (np->cork.rt) {
1407                 dst_release(&np->cork.rt->u.dst);
1408                 np->cork.rt = NULL;
1409                 inet->cork.flags &= ~IPCORK_ALLFRAG;
1410         }
1411         memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1412 }