1 /* 2 * IPv6 output functions 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * Based on linux/net/ipv4/ip_output.c 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 * 15 * Changes: 16 * A.N.Kuznetsov : airthmetics in fragmentation. 17 * extension headers are implemented. 18 * route changes now work. 19 * ip6_forward does not confuse sniffers. 20 * etc. 21 * 22 * H. von Brand : Added missing #include <linux/string.h> 23 * Imran Patel : frag id should be in NBO 24 * Kazunori MIYAZAWA @USAGI 25 * : add ip6_append_data and related functions 26 * for datagram xmit 27 */ 28 29 #include <linux/errno.h> 30 #include <linux/kernel.h> 31 #include <linux/string.h> 32 #include <linux/socket.h> 33 #include <linux/net.h> 34 #include <linux/netdevice.h> 35 #include <linux/if_arp.h> 36 #include <linux/in6.h> 37 #include <linux/tcp.h> 38 #include <linux/route.h> 39 #include <linux/module.h> 40 #include <linux/slab.h> 41 42 #include <linux/netfilter.h> 43 #include <linux/netfilter_ipv6.h> 44 45 #include <net/sock.h> 46 #include <net/snmp.h> 47 48 #include <net/ipv6.h> 49 #include <net/ndisc.h> 50 #include <net/protocol.h> 51 #include <net/ip6_route.h> 52 #include <net/addrconf.h> 53 #include <net/rawv6.h> 54 #include <net/icmp.h> 55 #include <net/xfrm.h> 56 #include <net/checksum.h> 57 #include <linux/mroute6.h> 58 59 static int ip6_finish_output2(struct sk_buff *skb) 60 { 61 struct dst_entry *dst = skb_dst(skb); 62 struct net_device *dev = dst->dev; 63 struct neighbour *neigh; 64 struct in6_addr *nexthop; 65 int ret; 66 67 skb->protocol = htons(ETH_P_IPV6); 68 skb->dev = dev; 69 70 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { 71 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 72 73 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) && 74 ((mroute6_socket(dev_net(dev), skb) && 75 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 76 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, 77 &ipv6_hdr(skb)->saddr))) { 78 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 79 80 /* Do not check for IFF_ALLMULTI; multicast routing 81 is not supported in any case. 82 */ 83 if (newskb) 84 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 85 newskb, NULL, newskb->dev, 86 dev_loopback_xmit); 87 88 if (ipv6_hdr(skb)->hop_limit == 0) { 89 IP6_INC_STATS(dev_net(dev), idev, 90 IPSTATS_MIB_OUTDISCARDS); 91 kfree_skb(skb); 92 return 0; 93 } 94 } 95 96 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST, 97 skb->len); 98 99 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <= 100 IPV6_ADDR_SCOPE_NODELOCAL && 101 !(dev->flags & IFF_LOOPBACK)) { 102 kfree_skb(skb); 103 return 0; 104 } 105 } 106 107 rcu_read_lock_bh(); 108 nexthop = rt6_nexthop((struct rt6_info *)dst); 109 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop); 110 if (unlikely(!neigh)) 111 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false); 112 if (!IS_ERR(neigh)) { 113 ret = dst_neigh_output(dst, neigh, skb); 114 rcu_read_unlock_bh(); 115 return ret; 116 } 117 rcu_read_unlock_bh(); 118 119 IP6_INC_STATS(dev_net(dst->dev), 120 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 121 kfree_skb(skb); 122 return -EINVAL; 123 } 124 125 static int ip6_finish_output(struct sk_buff *skb) 126 { 127 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || 128 dst_allfrag(skb_dst(skb)) || 129 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) 130 return ip6_fragment(skb, ip6_finish_output2); 131 else 132 return ip6_finish_output2(skb); 133 } 134 135 int ip6_output(struct sock *sk, struct sk_buff *skb) 136 { 137 struct net_device *dev = skb_dst(skb)->dev; 138 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 139 if (unlikely(idev->cnf.disable_ipv6)) { 140 IP6_INC_STATS(dev_net(dev), idev, 141 IPSTATS_MIB_OUTDISCARDS); 142 kfree_skb(skb); 143 return 0; 144 } 145 146 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev, 147 ip6_finish_output, 148 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 149 } 150 151 /* 152 * xmit an sk_buff (used by TCP, SCTP and DCCP) 153 */ 154 155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 156 struct ipv6_txoptions *opt, int tclass) 157 { 158 struct net *net = sock_net(sk); 159 struct ipv6_pinfo *np = inet6_sk(sk); 160 struct in6_addr *first_hop = &fl6->daddr; 161 struct dst_entry *dst = skb_dst(skb); 162 struct ipv6hdr *hdr; 163 u8 proto = fl6->flowi6_proto; 164 int seg_len = skb->len; 165 int hlimit = -1; 166 u32 mtu; 167 168 if (opt) { 169 unsigned int head_room; 170 171 /* First: exthdrs may take lots of space (~8K for now) 172 MAX_HEADER is not enough. 173 */ 174 head_room = opt->opt_nflen + opt->opt_flen; 175 seg_len += head_room; 176 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 177 178 if (skb_headroom(skb) < head_room) { 179 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 180 if (skb2 == NULL) { 181 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 182 IPSTATS_MIB_OUTDISCARDS); 183 kfree_skb(skb); 184 return -ENOBUFS; 185 } 186 consume_skb(skb); 187 skb = skb2; 188 skb_set_owner_w(skb, sk); 189 } 190 if (opt->opt_flen) 191 ipv6_push_frag_opts(skb, opt, &proto); 192 if (opt->opt_nflen) 193 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 194 } 195 196 skb_push(skb, sizeof(struct ipv6hdr)); 197 skb_reset_network_header(skb); 198 hdr = ipv6_hdr(skb); 199 200 /* 201 * Fill in the IPv6 header 202 */ 203 if (np) 204 hlimit = np->hop_limit; 205 if (hlimit < 0) 206 hlimit = ip6_dst_hoplimit(dst); 207 208 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 209 np->autoflowlabel)); 210 211 hdr->payload_len = htons(seg_len); 212 hdr->nexthdr = proto; 213 hdr->hop_limit = hlimit; 214 215 hdr->saddr = fl6->saddr; 216 hdr->daddr = *first_hop; 217 218 skb->protocol = htons(ETH_P_IPV6); 219 skb->priority = sk->sk_priority; 220 skb->mark = sk->sk_mark; 221 222 mtu = dst_mtu(dst); 223 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 224 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 225 IPSTATS_MIB_OUT, skb->len); 226 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 227 dst->dev, dst_output); 228 } 229 230 skb->dev = dst->dev; 231 ipv6_local_error(sk, EMSGSIZE, fl6, mtu); 232 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 233 kfree_skb(skb); 234 return -EMSGSIZE; 235 } 236 EXPORT_SYMBOL(ip6_xmit); 237 238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 239 { 240 struct ip6_ra_chain *ra; 241 struct sock *last = NULL; 242 243 read_lock(&ip6_ra_lock); 244 for (ra = ip6_ra_chain; ra; ra = ra->next) { 245 struct sock *sk = ra->sk; 246 if (sk && ra->sel == sel && 247 (!sk->sk_bound_dev_if || 248 sk->sk_bound_dev_if == skb->dev->ifindex)) { 249 if (last) { 250 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 251 if (skb2) 252 rawv6_rcv(last, skb2); 253 } 254 last = sk; 255 } 256 } 257 258 if (last) { 259 rawv6_rcv(last, skb); 260 read_unlock(&ip6_ra_lock); 261 return 1; 262 } 263 read_unlock(&ip6_ra_lock); 264 return 0; 265 } 266 267 static int ip6_forward_proxy_check(struct sk_buff *skb) 268 { 269 struct ipv6hdr *hdr = ipv6_hdr(skb); 270 u8 nexthdr = hdr->nexthdr; 271 __be16 frag_off; 272 int offset; 273 274 if (ipv6_ext_hdr(nexthdr)) { 275 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 276 if (offset < 0) 277 return 0; 278 } else 279 offset = sizeof(struct ipv6hdr); 280 281 if (nexthdr == IPPROTO_ICMPV6) { 282 struct icmp6hdr *icmp6; 283 284 if (!pskb_may_pull(skb, (skb_network_header(skb) + 285 offset + 1 - skb->data))) 286 return 0; 287 288 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 289 290 switch (icmp6->icmp6_type) { 291 case NDISC_ROUTER_SOLICITATION: 292 case NDISC_ROUTER_ADVERTISEMENT: 293 case NDISC_NEIGHBOUR_SOLICITATION: 294 case NDISC_NEIGHBOUR_ADVERTISEMENT: 295 case NDISC_REDIRECT: 296 /* For reaction involving unicast neighbor discovery 297 * message destined to the proxied address, pass it to 298 * input function. 299 */ 300 return 1; 301 default: 302 break; 303 } 304 } 305 306 /* 307 * The proxying router can't forward traffic sent to a link-local 308 * address, so signal the sender and discard the packet. This 309 * behavior is clarified by the MIPv6 specification. 310 */ 311 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 312 dst_link_failure(skb); 313 return -1; 314 } 315 316 return 0; 317 } 318 319 static inline int ip6_forward_finish(struct sk_buff *skb) 320 { 321 return dst_output(skb); 322 } 323 324 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst) 325 { 326 unsigned int mtu; 327 struct inet6_dev *idev; 328 329 if (dst_metric_locked(dst, RTAX_MTU)) { 330 mtu = dst_metric_raw(dst, RTAX_MTU); 331 if (mtu) 332 return mtu; 333 } 334 335 mtu = IPV6_MIN_MTU; 336 rcu_read_lock(); 337 idev = __in6_dev_get(dst->dev); 338 if (idev) 339 mtu = idev->cnf.mtu6; 340 rcu_read_unlock(); 341 342 return mtu; 343 } 344 345 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 346 { 347 if (skb->len <= mtu) 348 return false; 349 350 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 351 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 352 return true; 353 354 if (skb->ignore_df) 355 return false; 356 357 if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) 358 return false; 359 360 return true; 361 } 362 363 int ip6_forward(struct sk_buff *skb) 364 { 365 struct dst_entry *dst = skb_dst(skb); 366 struct ipv6hdr *hdr = ipv6_hdr(skb); 367 struct inet6_skb_parm *opt = IP6CB(skb); 368 struct net *net = dev_net(dst->dev); 369 u32 mtu; 370 371 if (net->ipv6.devconf_all->forwarding == 0) 372 goto error; 373 374 if (skb->pkt_type != PACKET_HOST) 375 goto drop; 376 377 if (skb_warn_if_lro(skb)) 378 goto drop; 379 380 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 381 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 382 IPSTATS_MIB_INDISCARDS); 383 goto drop; 384 } 385 386 skb_forward_csum(skb); 387 388 /* 389 * We DO NOT make any processing on 390 * RA packets, pushing them to user level AS IS 391 * without ane WARRANTY that application will be able 392 * to interpret them. The reason is that we 393 * cannot make anything clever here. 394 * 395 * We are not end-node, so that if packet contains 396 * AH/ESP, we cannot make anything. 397 * Defragmentation also would be mistake, RA packets 398 * cannot be fragmented, because there is no warranty 399 * that different fragments will go along one path. --ANK 400 */ 401 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 402 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 403 return 0; 404 } 405 406 /* 407 * check and decrement ttl 408 */ 409 if (hdr->hop_limit <= 1) { 410 /* Force OUTPUT device used as source address */ 411 skb->dev = dst->dev; 412 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 413 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 414 IPSTATS_MIB_INHDRERRORS); 415 416 kfree_skb(skb); 417 return -ETIMEDOUT; 418 } 419 420 /* XXX: idev->cnf.proxy_ndp? */ 421 if (net->ipv6.devconf_all->proxy_ndp && 422 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 423 int proxied = ip6_forward_proxy_check(skb); 424 if (proxied > 0) 425 return ip6_input(skb); 426 else if (proxied < 0) { 427 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 428 IPSTATS_MIB_INDISCARDS); 429 goto drop; 430 } 431 } 432 433 if (!xfrm6_route_forward(skb)) { 434 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 435 IPSTATS_MIB_INDISCARDS); 436 goto drop; 437 } 438 dst = skb_dst(skb); 439 440 /* IPv6 specs say nothing about it, but it is clear that we cannot 441 send redirects to source routed frames. 442 We don't send redirects to frames decapsulated from IPsec. 443 */ 444 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) { 445 struct in6_addr *target = NULL; 446 struct inet_peer *peer; 447 struct rt6_info *rt; 448 449 /* 450 * incoming and outgoing devices are the same 451 * send a redirect. 452 */ 453 454 rt = (struct rt6_info *) dst; 455 if (rt->rt6i_flags & RTF_GATEWAY) 456 target = &rt->rt6i_gateway; 457 else 458 target = &hdr->daddr; 459 460 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1); 461 462 /* Limit redirects both by destination (here) 463 and by source (inside ndisc_send_redirect) 464 */ 465 if (inet_peer_xrlim_allow(peer, 1*HZ)) 466 ndisc_send_redirect(skb, target); 467 if (peer) 468 inet_putpeer(peer); 469 } else { 470 int addrtype = ipv6_addr_type(&hdr->saddr); 471 472 /* This check is security critical. */ 473 if (addrtype == IPV6_ADDR_ANY || 474 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 475 goto error; 476 if (addrtype & IPV6_ADDR_LINKLOCAL) { 477 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 478 ICMPV6_NOT_NEIGHBOUR, 0); 479 goto error; 480 } 481 } 482 483 mtu = ip6_dst_mtu_forward(dst); 484 if (mtu < IPV6_MIN_MTU) 485 mtu = IPV6_MIN_MTU; 486 487 if (ip6_pkt_too_big(skb, mtu)) { 488 /* Again, force OUTPUT device used as source address */ 489 skb->dev = dst->dev; 490 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 491 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 492 IPSTATS_MIB_INTOOBIGERRORS); 493 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 494 IPSTATS_MIB_FRAGFAILS); 495 kfree_skb(skb); 496 return -EMSGSIZE; 497 } 498 499 if (skb_cow(skb, dst->dev->hard_header_len)) { 500 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 501 IPSTATS_MIB_OUTDISCARDS); 502 goto drop; 503 } 504 505 hdr = ipv6_hdr(skb); 506 507 /* Mangling hops number delayed to point after skb COW */ 508 509 hdr->hop_limit--; 510 511 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 512 IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 513 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev, 514 ip6_forward_finish); 515 516 error: 517 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); 518 drop: 519 kfree_skb(skb); 520 return -EINVAL; 521 } 522 523 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 524 { 525 to->pkt_type = from->pkt_type; 526 to->priority = from->priority; 527 to->protocol = from->protocol; 528 skb_dst_drop(to); 529 skb_dst_set(to, dst_clone(skb_dst(from))); 530 to->dev = from->dev; 531 to->mark = from->mark; 532 533 #ifdef CONFIG_NET_SCHED 534 to->tc_index = from->tc_index; 535 #endif 536 nf_copy(to, from); 537 skb_copy_secmark(to, from); 538 } 539 540 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 541 { 542 struct sk_buff *frag; 543 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 544 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 545 struct ipv6hdr *tmp_hdr; 546 struct frag_hdr *fh; 547 unsigned int mtu, hlen, left, len; 548 int hroom, troom; 549 __be32 frag_id = 0; 550 int ptr, offset = 0, err = 0; 551 u8 *prevhdr, nexthdr = 0; 552 struct net *net = dev_net(skb_dst(skb)->dev); 553 554 hlen = ip6_find_1stfragopt(skb, &prevhdr); 555 nexthdr = *prevhdr; 556 557 mtu = ip6_skb_dst_mtu(skb); 558 559 /* We must not fragment if the socket is set to force MTU discovery 560 * or if the skb it not generated by a local socket. 561 */ 562 if (unlikely(!skb->ignore_df && skb->len > mtu) || 563 (IP6CB(skb)->frag_max_size && 564 IP6CB(skb)->frag_max_size > mtu)) { 565 if (skb->sk && dst_allfrag(skb_dst(skb))) 566 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 567 568 skb->dev = skb_dst(skb)->dev; 569 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 570 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 571 IPSTATS_MIB_FRAGFAILS); 572 kfree_skb(skb); 573 return -EMSGSIZE; 574 } 575 576 if (np && np->frag_size < mtu) { 577 if (np->frag_size) 578 mtu = np->frag_size; 579 } 580 mtu -= hlen + sizeof(struct frag_hdr); 581 582 if (skb_has_frag_list(skb)) { 583 int first_len = skb_pagelen(skb); 584 struct sk_buff *frag2; 585 586 if (first_len - hlen > mtu || 587 ((first_len - hlen) & 7) || 588 skb_cloned(skb)) 589 goto slow_path; 590 591 skb_walk_frags(skb, frag) { 592 /* Correct geometry. */ 593 if (frag->len > mtu || 594 ((frag->len & 7) && frag->next) || 595 skb_headroom(frag) < hlen) 596 goto slow_path_clean; 597 598 /* Partially cloned skb? */ 599 if (skb_shared(frag)) 600 goto slow_path_clean; 601 602 BUG_ON(frag->sk); 603 if (skb->sk) { 604 frag->sk = skb->sk; 605 frag->destructor = sock_wfree; 606 } 607 skb->truesize -= frag->truesize; 608 } 609 610 err = 0; 611 offset = 0; 612 frag = skb_shinfo(skb)->frag_list; 613 skb_frag_list_init(skb); 614 /* BUILD HEADER */ 615 616 *prevhdr = NEXTHDR_FRAGMENT; 617 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 618 if (!tmp_hdr) { 619 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 620 IPSTATS_MIB_FRAGFAILS); 621 return -ENOMEM; 622 } 623 624 __skb_pull(skb, hlen); 625 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr)); 626 __skb_push(skb, hlen); 627 skb_reset_network_header(skb); 628 memcpy(skb_network_header(skb), tmp_hdr, hlen); 629 630 ipv6_select_ident(fh, rt); 631 fh->nexthdr = nexthdr; 632 fh->reserved = 0; 633 fh->frag_off = htons(IP6_MF); 634 frag_id = fh->identification; 635 636 first_len = skb_pagelen(skb); 637 skb->data_len = first_len - skb_headlen(skb); 638 skb->len = first_len; 639 ipv6_hdr(skb)->payload_len = htons(first_len - 640 sizeof(struct ipv6hdr)); 641 642 dst_hold(&rt->dst); 643 644 for (;;) { 645 /* Prepare header of the next frame, 646 * before previous one went down. */ 647 if (frag) { 648 frag->ip_summed = CHECKSUM_NONE; 649 skb_reset_transport_header(frag); 650 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr)); 651 __skb_push(frag, hlen); 652 skb_reset_network_header(frag); 653 memcpy(skb_network_header(frag), tmp_hdr, 654 hlen); 655 offset += skb->len - hlen - sizeof(struct frag_hdr); 656 fh->nexthdr = nexthdr; 657 fh->reserved = 0; 658 fh->frag_off = htons(offset); 659 if (frag->next != NULL) 660 fh->frag_off |= htons(IP6_MF); 661 fh->identification = frag_id; 662 ipv6_hdr(frag)->payload_len = 663 htons(frag->len - 664 sizeof(struct ipv6hdr)); 665 ip6_copy_metadata(frag, skb); 666 } 667 668 err = output(skb); 669 if (!err) 670 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 671 IPSTATS_MIB_FRAGCREATES); 672 673 if (err || !frag) 674 break; 675 676 skb = frag; 677 frag = skb->next; 678 skb->next = NULL; 679 } 680 681 kfree(tmp_hdr); 682 683 if (err == 0) { 684 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 685 IPSTATS_MIB_FRAGOKS); 686 ip6_rt_put(rt); 687 return 0; 688 } 689 690 kfree_skb_list(frag); 691 692 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 693 IPSTATS_MIB_FRAGFAILS); 694 ip6_rt_put(rt); 695 return err; 696 697 slow_path_clean: 698 skb_walk_frags(skb, frag2) { 699 if (frag2 == frag) 700 break; 701 frag2->sk = NULL; 702 frag2->destructor = NULL; 703 skb->truesize += frag2->truesize; 704 } 705 } 706 707 slow_path: 708 if ((skb->ip_summed == CHECKSUM_PARTIAL) && 709 skb_checksum_help(skb)) 710 goto fail; 711 712 left = skb->len - hlen; /* Space per frame */ 713 ptr = hlen; /* Where to start from */ 714 715 /* 716 * Fragment the datagram. 717 */ 718 719 *prevhdr = NEXTHDR_FRAGMENT; 720 hroom = LL_RESERVED_SPACE(rt->dst.dev); 721 troom = rt->dst.dev->needed_tailroom; 722 723 /* 724 * Keep copying data until we run out. 725 */ 726 while (left > 0) { 727 len = left; 728 /* IF: it doesn't fit, use 'mtu' - the data space left */ 729 if (len > mtu) 730 len = mtu; 731 /* IF: we are not sending up to and including the packet end 732 then align the next start on an eight byte boundary */ 733 if (len < left) { 734 len &= ~7; 735 } 736 737 /* Allocate buffer */ 738 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 739 hroom + troom, GFP_ATOMIC); 740 if (!frag) { 741 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 742 IPSTATS_MIB_FRAGFAILS); 743 err = -ENOMEM; 744 goto fail; 745 } 746 747 /* 748 * Set up data on packet 749 */ 750 751 ip6_copy_metadata(frag, skb); 752 skb_reserve(frag, hroom); 753 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 754 skb_reset_network_header(frag); 755 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 756 frag->transport_header = (frag->network_header + hlen + 757 sizeof(struct frag_hdr)); 758 759 /* 760 * Charge the memory for the fragment to any owner 761 * it might possess 762 */ 763 if (skb->sk) 764 skb_set_owner_w(frag, skb->sk); 765 766 /* 767 * Copy the packet header into the new buffer. 768 */ 769 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 770 771 /* 772 * Build fragment header. 773 */ 774 fh->nexthdr = nexthdr; 775 fh->reserved = 0; 776 if (!frag_id) { 777 ipv6_select_ident(fh, rt); 778 frag_id = fh->identification; 779 } else 780 fh->identification = frag_id; 781 782 /* 783 * Copy a block of the IP datagram. 784 */ 785 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag), 786 len)); 787 left -= len; 788 789 fh->frag_off = htons(offset); 790 if (left > 0) 791 fh->frag_off |= htons(IP6_MF); 792 ipv6_hdr(frag)->payload_len = htons(frag->len - 793 sizeof(struct ipv6hdr)); 794 795 ptr += len; 796 offset += len; 797 798 /* 799 * Put this fragment into the sending queue. 800 */ 801 err = output(frag); 802 if (err) 803 goto fail; 804 805 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 806 IPSTATS_MIB_FRAGCREATES); 807 } 808 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 809 IPSTATS_MIB_FRAGOKS); 810 consume_skb(skb); 811 return err; 812 813 fail: 814 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 815 IPSTATS_MIB_FRAGFAILS); 816 kfree_skb(skb); 817 return err; 818 } 819 820 static inline int ip6_rt_check(const struct rt6key *rt_key, 821 const struct in6_addr *fl_addr, 822 const struct in6_addr *addr_cache) 823 { 824 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 825 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)); 826 } 827 828 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 829 struct dst_entry *dst, 830 const struct flowi6 *fl6) 831 { 832 struct ipv6_pinfo *np = inet6_sk(sk); 833 struct rt6_info *rt; 834 835 if (!dst) 836 goto out; 837 838 if (dst->ops->family != AF_INET6) { 839 dst_release(dst); 840 return NULL; 841 } 842 843 rt = (struct rt6_info *)dst; 844 /* Yes, checking route validity in not connected 845 * case is not very simple. Take into account, 846 * that we do not support routing by source, TOS, 847 * and MSG_DONTROUTE --ANK (980726) 848 * 849 * 1. ip6_rt_check(): If route was host route, 850 * check that cached destination is current. 851 * If it is network route, we still may 852 * check its validity using saved pointer 853 * to the last used address: daddr_cache. 854 * We do not want to save whole address now, 855 * (because main consumer of this service 856 * is tcp, which has not this problem), 857 * so that the last trick works only on connected 858 * sockets. 859 * 2. oif also should be the same. 860 */ 861 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 862 #ifdef CONFIG_IPV6_SUBTREES 863 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 864 #endif 865 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 866 dst_release(dst); 867 dst = NULL; 868 } 869 870 out: 871 return dst; 872 } 873 874 static int ip6_dst_lookup_tail(struct sock *sk, 875 struct dst_entry **dst, struct flowi6 *fl6) 876 { 877 struct net *net = sock_net(sk); 878 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 879 struct neighbour *n; 880 struct rt6_info *rt; 881 #endif 882 int err; 883 884 if (*dst == NULL) 885 *dst = ip6_route_output(net, sk, fl6); 886 887 err = (*dst)->error; 888 if (err) 889 goto out_err_release; 890 891 if (ipv6_addr_any(&fl6->saddr)) { 892 struct rt6_info *rt = (struct rt6_info *) *dst; 893 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 894 sk ? inet6_sk(sk)->srcprefs : 0, 895 &fl6->saddr); 896 if (err) 897 goto out_err_release; 898 } 899 900 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 901 /* 902 * Here if the dst entry we've looked up 903 * has a neighbour entry that is in the INCOMPLETE 904 * state and the src address from the flow is 905 * marked as OPTIMISTIC, we release the found 906 * dst entry and replace it instead with the 907 * dst entry of the nexthop router 908 */ 909 rt = (struct rt6_info *) *dst; 910 rcu_read_lock_bh(); 911 n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt)); 912 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 913 rcu_read_unlock_bh(); 914 915 if (err) { 916 struct inet6_ifaddr *ifp; 917 struct flowi6 fl_gw6; 918 int redirect; 919 920 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 921 (*dst)->dev, 1); 922 923 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 924 if (ifp) 925 in6_ifa_put(ifp); 926 927 if (redirect) { 928 /* 929 * We need to get the dst entry for the 930 * default router instead 931 */ 932 dst_release(*dst); 933 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 934 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 935 *dst = ip6_route_output(net, sk, &fl_gw6); 936 err = (*dst)->error; 937 if (err) 938 goto out_err_release; 939 } 940 } 941 #endif 942 943 return 0; 944 945 out_err_release: 946 if (err == -ENETUNREACH) 947 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 948 dst_release(*dst); 949 *dst = NULL; 950 return err; 951 } 952 953 /** 954 * ip6_dst_lookup - perform route lookup on flow 955 * @sk: socket which provides route info 956 * @dst: pointer to dst_entry * for result 957 * @fl6: flow to lookup 958 * 959 * This function performs a route lookup on the given flow. 960 * 961 * It returns zero on success, or a standard errno code on error. 962 */ 963 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6) 964 { 965 *dst = NULL; 966 return ip6_dst_lookup_tail(sk, dst, fl6); 967 } 968 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 969 970 /** 971 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 972 * @sk: socket which provides route info 973 * @fl6: flow to lookup 974 * @final_dst: final destination address for ipsec lookup 975 * 976 * This function performs a route lookup on the given flow. 977 * 978 * It returns a valid dst pointer on success, or a pointer encoded 979 * error code. 980 */ 981 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 982 const struct in6_addr *final_dst) 983 { 984 struct dst_entry *dst = NULL; 985 int err; 986 987 err = ip6_dst_lookup_tail(sk, &dst, fl6); 988 if (err) 989 return ERR_PTR(err); 990 if (final_dst) 991 fl6->daddr = *final_dst; 992 993 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 994 } 995 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 996 997 /** 998 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 999 * @sk: socket which provides the dst cache and route info 1000 * @fl6: flow to lookup 1001 * @final_dst: final destination address for ipsec lookup 1002 * 1003 * This function performs a route lookup on the given flow with the 1004 * possibility of using the cached route in the socket if it is valid. 1005 * It will take the socket dst lock when operating on the dst cache. 1006 * As a result, this function can only be used in process context. 1007 * 1008 * It returns a valid dst pointer on success, or a pointer encoded 1009 * error code. 1010 */ 1011 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1012 const struct in6_addr *final_dst) 1013 { 1014 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1015 int err; 1016 1017 dst = ip6_sk_dst_check(sk, dst, fl6); 1018 1019 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1020 if (err) 1021 return ERR_PTR(err); 1022 if (final_dst) 1023 fl6->daddr = *final_dst; 1024 1025 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1026 } 1027 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1028 1029 static inline int ip6_ufo_append_data(struct sock *sk, 1030 struct sk_buff_head *queue, 1031 int getfrag(void *from, char *to, int offset, int len, 1032 int odd, struct sk_buff *skb), 1033 void *from, int length, int hh_len, int fragheaderlen, 1034 int transhdrlen, int mtu, unsigned int flags, 1035 struct rt6_info *rt) 1036 1037 { 1038 struct sk_buff *skb; 1039 struct frag_hdr fhdr; 1040 int err; 1041 1042 /* There is support for UDP large send offload by network 1043 * device, so create one single skb packet containing complete 1044 * udp datagram 1045 */ 1046 skb = skb_peek_tail(queue); 1047 if (skb == NULL) { 1048 skb = sock_alloc_send_skb(sk, 1049 hh_len + fragheaderlen + transhdrlen + 20, 1050 (flags & MSG_DONTWAIT), &err); 1051 if (skb == NULL) 1052 return err; 1053 1054 /* reserve space for Hardware header */ 1055 skb_reserve(skb, hh_len); 1056 1057 /* create space for UDP/IP header */ 1058 skb_put(skb, fragheaderlen + transhdrlen); 1059 1060 /* initialize network header pointer */ 1061 skb_reset_network_header(skb); 1062 1063 /* initialize protocol header pointer */ 1064 skb->transport_header = skb->network_header + fragheaderlen; 1065 1066 skb->protocol = htons(ETH_P_IPV6); 1067 skb->csum = 0; 1068 1069 __skb_queue_tail(queue, skb); 1070 } else if (skb_is_gso(skb)) { 1071 goto append; 1072 } 1073 1074 skb->ip_summed = CHECKSUM_PARTIAL; 1075 /* Specify the length of each IPv6 datagram fragment. 1076 * It has to be a multiple of 8. 1077 */ 1078 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1079 sizeof(struct frag_hdr)) & ~7; 1080 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1081 ipv6_select_ident(&fhdr, rt); 1082 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 1083 1084 append: 1085 return skb_append_datato_frags(sk, skb, getfrag, from, 1086 (length - transhdrlen)); 1087 } 1088 1089 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1090 gfp_t gfp) 1091 { 1092 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1093 } 1094 1095 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1096 gfp_t gfp) 1097 { 1098 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1099 } 1100 1101 static void ip6_append_data_mtu(unsigned int *mtu, 1102 int *maxfraglen, 1103 unsigned int fragheaderlen, 1104 struct sk_buff *skb, 1105 struct rt6_info *rt, 1106 unsigned int orig_mtu) 1107 { 1108 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1109 if (skb == NULL) { 1110 /* first fragment, reserve header_len */ 1111 *mtu = orig_mtu - rt->dst.header_len; 1112 1113 } else { 1114 /* 1115 * this fragment is not first, the headers 1116 * space is regarded as data space. 1117 */ 1118 *mtu = orig_mtu; 1119 } 1120 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1121 + fragheaderlen - sizeof(struct frag_hdr); 1122 } 1123 } 1124 1125 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1126 struct inet6_cork *v6_cork, 1127 int hlimit, int tclass, struct ipv6_txoptions *opt, 1128 struct rt6_info *rt, struct flowi6 *fl6) 1129 { 1130 struct ipv6_pinfo *np = inet6_sk(sk); 1131 unsigned int mtu; 1132 1133 /* 1134 * setup for corking 1135 */ 1136 if (opt) { 1137 if (WARN_ON(v6_cork->opt)) 1138 return -EINVAL; 1139 1140 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation); 1141 if (unlikely(v6_cork->opt == NULL)) 1142 return -ENOBUFS; 1143 1144 v6_cork->opt->tot_len = opt->tot_len; 1145 v6_cork->opt->opt_flen = opt->opt_flen; 1146 v6_cork->opt->opt_nflen = opt->opt_nflen; 1147 1148 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1149 sk->sk_allocation); 1150 if (opt->dst0opt && !v6_cork->opt->dst0opt) 1151 return -ENOBUFS; 1152 1153 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1154 sk->sk_allocation); 1155 if (opt->dst1opt && !v6_cork->opt->dst1opt) 1156 return -ENOBUFS; 1157 1158 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt, 1159 sk->sk_allocation); 1160 if (opt->hopopt && !v6_cork->opt->hopopt) 1161 return -ENOBUFS; 1162 1163 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1164 sk->sk_allocation); 1165 if (opt->srcrt && !v6_cork->opt->srcrt) 1166 return -ENOBUFS; 1167 1168 /* need source address above miyazawa*/ 1169 } 1170 dst_hold(&rt->dst); 1171 cork->base.dst = &rt->dst; 1172 cork->fl.u.ip6 = *fl6; 1173 v6_cork->hop_limit = hlimit; 1174 v6_cork->tclass = tclass; 1175 if (rt->dst.flags & DST_XFRM_TUNNEL) 1176 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1177 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1178 else 1179 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1180 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1181 if (np->frag_size < mtu) { 1182 if (np->frag_size) 1183 mtu = np->frag_size; 1184 } 1185 cork->base.fragsize = mtu; 1186 if (dst_allfrag(rt->dst.path)) 1187 cork->base.flags |= IPCORK_ALLFRAG; 1188 cork->base.length = 0; 1189 1190 return 0; 1191 } 1192 1193 static int __ip6_append_data(struct sock *sk, 1194 struct flowi6 *fl6, 1195 struct sk_buff_head *queue, 1196 struct inet_cork *cork, 1197 struct inet6_cork *v6_cork, 1198 struct page_frag *pfrag, 1199 int getfrag(void *from, char *to, int offset, 1200 int len, int odd, struct sk_buff *skb), 1201 void *from, int length, int transhdrlen, 1202 unsigned int flags, int dontfrag) 1203 { 1204 struct sk_buff *skb, *skb_prev = NULL; 1205 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1206 int exthdrlen = 0; 1207 int dst_exthdrlen = 0; 1208 int hh_len; 1209 int copy; 1210 int err; 1211 int offset = 0; 1212 __u8 tx_flags = 0; 1213 u32 tskey = 0; 1214 struct rt6_info *rt = (struct rt6_info *)cork->dst; 1215 struct ipv6_txoptions *opt = v6_cork->opt; 1216 int csummode = CHECKSUM_NONE; 1217 1218 skb = skb_peek_tail(queue); 1219 if (!skb) { 1220 exthdrlen = opt ? opt->opt_flen : 0; 1221 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1222 } 1223 1224 mtu = cork->fragsize; 1225 orig_mtu = mtu; 1226 1227 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1228 1229 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1230 (opt ? opt->opt_nflen : 0); 1231 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1232 sizeof(struct frag_hdr); 1233 1234 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1235 unsigned int maxnonfragsize, headersize; 1236 1237 headersize = sizeof(struct ipv6hdr) + 1238 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1239 (dst_allfrag(&rt->dst) ? 1240 sizeof(struct frag_hdr) : 0) + 1241 rt->rt6i_nfheader_len; 1242 1243 if (ip6_sk_ignore_df(sk)) 1244 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1245 else 1246 maxnonfragsize = mtu; 1247 1248 /* dontfrag active */ 1249 if ((cork->length + length > mtu - headersize) && dontfrag && 1250 (sk->sk_protocol == IPPROTO_UDP || 1251 sk->sk_protocol == IPPROTO_RAW)) { 1252 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1253 sizeof(struct ipv6hdr)); 1254 goto emsgsize; 1255 } 1256 1257 if (cork->length + length > maxnonfragsize - headersize) { 1258 emsgsize: 1259 ipv6_local_error(sk, EMSGSIZE, fl6, 1260 mtu - headersize + 1261 sizeof(struct ipv6hdr)); 1262 return -EMSGSIZE; 1263 } 1264 } 1265 1266 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1267 sock_tx_timestamp(sk, &tx_flags); 1268 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1269 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1270 tskey = sk->sk_tskey++; 1271 } 1272 1273 /* If this is the first and only packet and device 1274 * supports checksum offloading, let's use it. 1275 */ 1276 if (!skb && sk->sk_protocol == IPPROTO_UDP && 1277 length + fragheaderlen < mtu && 1278 rt->dst.dev->features & NETIF_F_V6_CSUM && 1279 !exthdrlen) 1280 csummode = CHECKSUM_PARTIAL; 1281 /* 1282 * Let's try using as much space as possible. 1283 * Use MTU if total length of the message fits into the MTU. 1284 * Otherwise, we need to reserve fragment header and 1285 * fragment alignment (= 8-15 octects, in total). 1286 * 1287 * Note that we may need to "move" the data from the tail of 1288 * of the buffer to the new fragment when we split 1289 * the message. 1290 * 1291 * FIXME: It may be fragmented into multiple chunks 1292 * at once if non-fragmentable extension headers 1293 * are too large. 1294 * --yoshfuji 1295 */ 1296 1297 cork->length += length; 1298 if (((length > mtu) || 1299 (skb && skb_is_gso(skb))) && 1300 (sk->sk_protocol == IPPROTO_UDP) && 1301 (rt->dst.dev->features & NETIF_F_UFO) && 1302 (sk->sk_type == SOCK_DGRAM)) { 1303 err = ip6_ufo_append_data(sk, queue, getfrag, from, length, 1304 hh_len, fragheaderlen, 1305 transhdrlen, mtu, flags, rt); 1306 if (err) 1307 goto error; 1308 return 0; 1309 } 1310 1311 if (!skb) 1312 goto alloc_new_skb; 1313 1314 while (length > 0) { 1315 /* Check if the remaining data fits into current packet. */ 1316 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1317 if (copy < length) 1318 copy = maxfraglen - skb->len; 1319 1320 if (copy <= 0) { 1321 char *data; 1322 unsigned int datalen; 1323 unsigned int fraglen; 1324 unsigned int fraggap; 1325 unsigned int alloclen; 1326 alloc_new_skb: 1327 /* There's no room in the current skb */ 1328 if (skb) 1329 fraggap = skb->len - maxfraglen; 1330 else 1331 fraggap = 0; 1332 /* update mtu and maxfraglen if necessary */ 1333 if (skb == NULL || skb_prev == NULL) 1334 ip6_append_data_mtu(&mtu, &maxfraglen, 1335 fragheaderlen, skb, rt, 1336 orig_mtu); 1337 1338 skb_prev = skb; 1339 1340 /* 1341 * If remaining data exceeds the mtu, 1342 * we know we need more fragment(s). 1343 */ 1344 datalen = length + fraggap; 1345 1346 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1347 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1348 if ((flags & MSG_MORE) && 1349 !(rt->dst.dev->features&NETIF_F_SG)) 1350 alloclen = mtu; 1351 else 1352 alloclen = datalen + fragheaderlen; 1353 1354 alloclen += dst_exthdrlen; 1355 1356 if (datalen != length + fraggap) { 1357 /* 1358 * this is not the last fragment, the trailer 1359 * space is regarded as data space. 1360 */ 1361 datalen += rt->dst.trailer_len; 1362 } 1363 1364 alloclen += rt->dst.trailer_len; 1365 fraglen = datalen + fragheaderlen; 1366 1367 /* 1368 * We just reserve space for fragment header. 1369 * Note: this may be overallocation if the message 1370 * (without MSG_MORE) fits into the MTU. 1371 */ 1372 alloclen += sizeof(struct frag_hdr); 1373 1374 if (transhdrlen) { 1375 skb = sock_alloc_send_skb(sk, 1376 alloclen + hh_len, 1377 (flags & MSG_DONTWAIT), &err); 1378 } else { 1379 skb = NULL; 1380 if (atomic_read(&sk->sk_wmem_alloc) <= 1381 2 * sk->sk_sndbuf) 1382 skb = sock_wmalloc(sk, 1383 alloclen + hh_len, 1, 1384 sk->sk_allocation); 1385 if (unlikely(skb == NULL)) 1386 err = -ENOBUFS; 1387 } 1388 if (skb == NULL) 1389 goto error; 1390 /* 1391 * Fill in the control structures 1392 */ 1393 skb->protocol = htons(ETH_P_IPV6); 1394 skb->ip_summed = csummode; 1395 skb->csum = 0; 1396 /* reserve for fragmentation and ipsec header */ 1397 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1398 dst_exthdrlen); 1399 1400 /* Only the initial fragment is time stamped */ 1401 skb_shinfo(skb)->tx_flags = tx_flags; 1402 tx_flags = 0; 1403 skb_shinfo(skb)->tskey = tskey; 1404 tskey = 0; 1405 1406 /* 1407 * Find where to start putting bytes 1408 */ 1409 data = skb_put(skb, fraglen); 1410 skb_set_network_header(skb, exthdrlen); 1411 data += fragheaderlen; 1412 skb->transport_header = (skb->network_header + 1413 fragheaderlen); 1414 if (fraggap) { 1415 skb->csum = skb_copy_and_csum_bits( 1416 skb_prev, maxfraglen, 1417 data + transhdrlen, fraggap, 0); 1418 skb_prev->csum = csum_sub(skb_prev->csum, 1419 skb->csum); 1420 data += fraggap; 1421 pskb_trim_unique(skb_prev, maxfraglen); 1422 } 1423 copy = datalen - transhdrlen - fraggap; 1424 1425 if (copy < 0) { 1426 err = -EINVAL; 1427 kfree_skb(skb); 1428 goto error; 1429 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1430 err = -EFAULT; 1431 kfree_skb(skb); 1432 goto error; 1433 } 1434 1435 offset += copy; 1436 length -= datalen - fraggap; 1437 transhdrlen = 0; 1438 exthdrlen = 0; 1439 dst_exthdrlen = 0; 1440 1441 /* 1442 * Put the packet on the pending queue 1443 */ 1444 __skb_queue_tail(queue, skb); 1445 continue; 1446 } 1447 1448 if (copy > length) 1449 copy = length; 1450 1451 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1452 unsigned int off; 1453 1454 off = skb->len; 1455 if (getfrag(from, skb_put(skb, copy), 1456 offset, copy, off, skb) < 0) { 1457 __skb_trim(skb, off); 1458 err = -EFAULT; 1459 goto error; 1460 } 1461 } else { 1462 int i = skb_shinfo(skb)->nr_frags; 1463 1464 err = -ENOMEM; 1465 if (!sk_page_frag_refill(sk, pfrag)) 1466 goto error; 1467 1468 if (!skb_can_coalesce(skb, i, pfrag->page, 1469 pfrag->offset)) { 1470 err = -EMSGSIZE; 1471 if (i == MAX_SKB_FRAGS) 1472 goto error; 1473 1474 __skb_fill_page_desc(skb, i, pfrag->page, 1475 pfrag->offset, 0); 1476 skb_shinfo(skb)->nr_frags = ++i; 1477 get_page(pfrag->page); 1478 } 1479 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1480 if (getfrag(from, 1481 page_address(pfrag->page) + pfrag->offset, 1482 offset, copy, skb->len, skb) < 0) 1483 goto error_efault; 1484 1485 pfrag->offset += copy; 1486 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1487 skb->len += copy; 1488 skb->data_len += copy; 1489 skb->truesize += copy; 1490 atomic_add(copy, &sk->sk_wmem_alloc); 1491 } 1492 offset += copy; 1493 length -= copy; 1494 } 1495 1496 return 0; 1497 1498 error_efault: 1499 err = -EFAULT; 1500 error: 1501 cork->length -= length; 1502 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1503 return err; 1504 } 1505 1506 int ip6_append_data(struct sock *sk, 1507 int getfrag(void *from, char *to, int offset, int len, 1508 int odd, struct sk_buff *skb), 1509 void *from, int length, int transhdrlen, int hlimit, 1510 int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1511 struct rt6_info *rt, unsigned int flags, int dontfrag) 1512 { 1513 struct inet_sock *inet = inet_sk(sk); 1514 struct ipv6_pinfo *np = inet6_sk(sk); 1515 int exthdrlen; 1516 int err; 1517 1518 if (flags&MSG_PROBE) 1519 return 0; 1520 if (skb_queue_empty(&sk->sk_write_queue)) { 1521 /* 1522 * setup for corking 1523 */ 1524 err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit, 1525 tclass, opt, rt, fl6); 1526 if (err) 1527 return err; 1528 1529 exthdrlen = (opt ? opt->opt_flen : 0); 1530 length += exthdrlen; 1531 transhdrlen += exthdrlen; 1532 } else { 1533 fl6 = &inet->cork.fl.u.ip6; 1534 transhdrlen = 0; 1535 } 1536 1537 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1538 &np->cork, sk_page_frag(sk), getfrag, 1539 from, length, transhdrlen, flags, dontfrag); 1540 } 1541 EXPORT_SYMBOL_GPL(ip6_append_data); 1542 1543 static void ip6_cork_release(struct inet_cork_full *cork, 1544 struct inet6_cork *v6_cork) 1545 { 1546 if (v6_cork->opt) { 1547 kfree(v6_cork->opt->dst0opt); 1548 kfree(v6_cork->opt->dst1opt); 1549 kfree(v6_cork->opt->hopopt); 1550 kfree(v6_cork->opt->srcrt); 1551 kfree(v6_cork->opt); 1552 v6_cork->opt = NULL; 1553 } 1554 1555 if (cork->base.dst) { 1556 dst_release(cork->base.dst); 1557 cork->base.dst = NULL; 1558 cork->base.flags &= ~IPCORK_ALLFRAG; 1559 } 1560 memset(&cork->fl, 0, sizeof(cork->fl)); 1561 } 1562 1563 struct sk_buff *__ip6_make_skb(struct sock *sk, 1564 struct sk_buff_head *queue, 1565 struct inet_cork_full *cork, 1566 struct inet6_cork *v6_cork) 1567 { 1568 struct sk_buff *skb, *tmp_skb; 1569 struct sk_buff **tail_skb; 1570 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1571 struct ipv6_pinfo *np = inet6_sk(sk); 1572 struct net *net = sock_net(sk); 1573 struct ipv6hdr *hdr; 1574 struct ipv6_txoptions *opt = v6_cork->opt; 1575 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1576 struct flowi6 *fl6 = &cork->fl.u.ip6; 1577 unsigned char proto = fl6->flowi6_proto; 1578 1579 skb = __skb_dequeue(queue); 1580 if (skb == NULL) 1581 goto out; 1582 tail_skb = &(skb_shinfo(skb)->frag_list); 1583 1584 /* move skb->data to ip header from ext header */ 1585 if (skb->data < skb_network_header(skb)) 1586 __skb_pull(skb, skb_network_offset(skb)); 1587 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1588 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1589 *tail_skb = tmp_skb; 1590 tail_skb = &(tmp_skb->next); 1591 skb->len += tmp_skb->len; 1592 skb->data_len += tmp_skb->len; 1593 skb->truesize += tmp_skb->truesize; 1594 tmp_skb->destructor = NULL; 1595 tmp_skb->sk = NULL; 1596 } 1597 1598 /* Allow local fragmentation. */ 1599 skb->ignore_df = ip6_sk_ignore_df(sk); 1600 1601 *final_dst = fl6->daddr; 1602 __skb_pull(skb, skb_network_header_len(skb)); 1603 if (opt && opt->opt_flen) 1604 ipv6_push_frag_opts(skb, opt, &proto); 1605 if (opt && opt->opt_nflen) 1606 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1607 1608 skb_push(skb, sizeof(struct ipv6hdr)); 1609 skb_reset_network_header(skb); 1610 hdr = ipv6_hdr(skb); 1611 1612 ip6_flow_hdr(hdr, v6_cork->tclass, 1613 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1614 np->autoflowlabel)); 1615 hdr->hop_limit = v6_cork->hop_limit; 1616 hdr->nexthdr = proto; 1617 hdr->saddr = fl6->saddr; 1618 hdr->daddr = *final_dst; 1619 1620 skb->priority = sk->sk_priority; 1621 skb->mark = sk->sk_mark; 1622 1623 skb_dst_set(skb, dst_clone(&rt->dst)); 1624 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1625 if (proto == IPPROTO_ICMPV6) { 1626 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1627 1628 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1629 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1630 } 1631 1632 ip6_cork_release(cork, v6_cork); 1633 out: 1634 return skb; 1635 } 1636 1637 int ip6_send_skb(struct sk_buff *skb) 1638 { 1639 struct net *net = sock_net(skb->sk); 1640 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1641 int err; 1642 1643 err = ip6_local_out(skb); 1644 if (err) { 1645 if (err > 0) 1646 err = net_xmit_errno(err); 1647 if (err) 1648 IP6_INC_STATS(net, rt->rt6i_idev, 1649 IPSTATS_MIB_OUTDISCARDS); 1650 } 1651 1652 return err; 1653 } 1654 1655 int ip6_push_pending_frames(struct sock *sk) 1656 { 1657 struct sk_buff *skb; 1658 1659 skb = ip6_finish_skb(sk); 1660 if (!skb) 1661 return 0; 1662 1663 return ip6_send_skb(skb); 1664 } 1665 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1666 1667 static void __ip6_flush_pending_frames(struct sock *sk, 1668 struct sk_buff_head *queue, 1669 struct inet_cork_full *cork, 1670 struct inet6_cork *v6_cork) 1671 { 1672 struct sk_buff *skb; 1673 1674 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1675 if (skb_dst(skb)) 1676 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1677 IPSTATS_MIB_OUTDISCARDS); 1678 kfree_skb(skb); 1679 } 1680 1681 ip6_cork_release(cork, v6_cork); 1682 } 1683 1684 void ip6_flush_pending_frames(struct sock *sk) 1685 { 1686 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1687 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1688 } 1689 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1690 1691 struct sk_buff *ip6_make_skb(struct sock *sk, 1692 int getfrag(void *from, char *to, int offset, 1693 int len, int odd, struct sk_buff *skb), 1694 void *from, int length, int transhdrlen, 1695 int hlimit, int tclass, 1696 struct ipv6_txoptions *opt, struct flowi6 *fl6, 1697 struct rt6_info *rt, unsigned int flags, 1698 int dontfrag) 1699 { 1700 struct inet_cork_full cork; 1701 struct inet6_cork v6_cork; 1702 struct sk_buff_head queue; 1703 int exthdrlen = (opt ? opt->opt_flen : 0); 1704 int err; 1705 1706 if (flags & MSG_PROBE) 1707 return NULL; 1708 1709 __skb_queue_head_init(&queue); 1710 1711 cork.base.flags = 0; 1712 cork.base.addr = 0; 1713 cork.base.opt = NULL; 1714 v6_cork.opt = NULL; 1715 err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6); 1716 if (err) 1717 return ERR_PTR(err); 1718 1719 if (dontfrag < 0) 1720 dontfrag = inet6_sk(sk)->dontfrag; 1721 1722 err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork, 1723 ¤t->task_frag, getfrag, from, 1724 length + exthdrlen, transhdrlen + exthdrlen, 1725 flags, dontfrag); 1726 if (err) { 1727 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork); 1728 return ERR_PTR(err); 1729 } 1730 1731 return __ip6_make_skb(sk, &queue, &cork, &v6_cork); 1732 } 1733