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 sock *sk, 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(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 sk, 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, &ipv6_hdr(skb)->daddr); 109 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop); 110 if (unlikely(!neigh)) 111 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false); 112 if (!IS_ERR(neigh)) { 113 ret = dst_neigh_output(dst, neigh, skb); 114 rcu_read_unlock_bh(); 115 return ret; 116 } 117 rcu_read_unlock_bh(); 118 119 IP6_INC_STATS(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 sock *sk, 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(sk, skb, ip6_finish_output2); 131 else 132 return ip6_finish_output2(sk, 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, sk, skb, 147 NULL, dev, 148 ip6_finish_output, 149 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 150 } 151 152 /* 153 * xmit an sk_buff (used by TCP, SCTP and DCCP) 154 */ 155 156 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 157 struct ipv6_txoptions *opt, int tclass) 158 { 159 struct net *net = sock_net(sk); 160 struct ipv6_pinfo *np = inet6_sk(sk); 161 struct in6_addr *first_hop = &fl6->daddr; 162 struct dst_entry *dst = skb_dst(skb); 163 struct ipv6hdr *hdr; 164 u8 proto = fl6->flowi6_proto; 165 int seg_len = skb->len; 166 int hlimit = -1; 167 u32 mtu; 168 169 if (opt) { 170 unsigned int head_room; 171 172 /* First: exthdrs may take lots of space (~8K for now) 173 MAX_HEADER is not enough. 174 */ 175 head_room = opt->opt_nflen + opt->opt_flen; 176 seg_len += head_room; 177 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 178 179 if (skb_headroom(skb) < head_room) { 180 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 181 if (!skb2) { 182 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 183 IPSTATS_MIB_OUTDISCARDS); 184 kfree_skb(skb); 185 return -ENOBUFS; 186 } 187 consume_skb(skb); 188 skb = skb2; 189 skb_set_owner_w(skb, sk); 190 } 191 if (opt->opt_flen) 192 ipv6_push_frag_opts(skb, opt, &proto); 193 if (opt->opt_nflen) 194 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 195 } 196 197 skb_push(skb, sizeof(struct ipv6hdr)); 198 skb_reset_network_header(skb); 199 hdr = ipv6_hdr(skb); 200 201 /* 202 * Fill in the IPv6 header 203 */ 204 if (np) 205 hlimit = np->hop_limit; 206 if (hlimit < 0) 207 hlimit = ip6_dst_hoplimit(dst); 208 209 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 210 np->autoflowlabel)); 211 212 hdr->payload_len = htons(seg_len); 213 hdr->nexthdr = proto; 214 hdr->hop_limit = hlimit; 215 216 hdr->saddr = fl6->saddr; 217 hdr->daddr = *first_hop; 218 219 skb->protocol = htons(ETH_P_IPV6); 220 skb->priority = sk->sk_priority; 221 skb->mark = sk->sk_mark; 222 223 mtu = dst_mtu(dst); 224 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 225 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 226 IPSTATS_MIB_OUT, skb->len); 227 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb, 228 NULL, dst->dev, dst_output_sk); 229 } 230 231 skb->dev = dst->dev; 232 ipv6_local_error(sk, EMSGSIZE, fl6, mtu); 233 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 234 kfree_skb(skb); 235 return -EMSGSIZE; 236 } 237 EXPORT_SYMBOL(ip6_xmit); 238 239 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 240 { 241 struct ip6_ra_chain *ra; 242 struct sock *last = NULL; 243 244 read_lock(&ip6_ra_lock); 245 for (ra = ip6_ra_chain; ra; ra = ra->next) { 246 struct sock *sk = ra->sk; 247 if (sk && ra->sel == sel && 248 (!sk->sk_bound_dev_if || 249 sk->sk_bound_dev_if == skb->dev->ifindex)) { 250 if (last) { 251 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 252 if (skb2) 253 rawv6_rcv(last, skb2); 254 } 255 last = sk; 256 } 257 } 258 259 if (last) { 260 rawv6_rcv(last, skb); 261 read_unlock(&ip6_ra_lock); 262 return 1; 263 } 264 read_unlock(&ip6_ra_lock); 265 return 0; 266 } 267 268 static int ip6_forward_proxy_check(struct sk_buff *skb) 269 { 270 struct ipv6hdr *hdr = ipv6_hdr(skb); 271 u8 nexthdr = hdr->nexthdr; 272 __be16 frag_off; 273 int offset; 274 275 if (ipv6_ext_hdr(nexthdr)) { 276 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 277 if (offset < 0) 278 return 0; 279 } else 280 offset = sizeof(struct ipv6hdr); 281 282 if (nexthdr == IPPROTO_ICMPV6) { 283 struct icmp6hdr *icmp6; 284 285 if (!pskb_may_pull(skb, (skb_network_header(skb) + 286 offset + 1 - skb->data))) 287 return 0; 288 289 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 290 291 switch (icmp6->icmp6_type) { 292 case NDISC_ROUTER_SOLICITATION: 293 case NDISC_ROUTER_ADVERTISEMENT: 294 case NDISC_NEIGHBOUR_SOLICITATION: 295 case NDISC_NEIGHBOUR_ADVERTISEMENT: 296 case NDISC_REDIRECT: 297 /* For reaction involving unicast neighbor discovery 298 * message destined to the proxied address, pass it to 299 * input function. 300 */ 301 return 1; 302 default: 303 break; 304 } 305 } 306 307 /* 308 * The proxying router can't forward traffic sent to a link-local 309 * address, so signal the sender and discard the packet. This 310 * behavior is clarified by the MIPv6 specification. 311 */ 312 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 313 dst_link_failure(skb); 314 return -1; 315 } 316 317 return 0; 318 } 319 320 static inline int ip6_forward_finish(struct sock *sk, struct sk_buff *skb) 321 { 322 skb_sender_cpu_clear(skb); 323 return dst_output_sk(sk, skb); 324 } 325 326 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst) 327 { 328 unsigned int mtu; 329 struct inet6_dev *idev; 330 331 if (dst_metric_locked(dst, RTAX_MTU)) { 332 mtu = dst_metric_raw(dst, RTAX_MTU); 333 if (mtu) 334 return mtu; 335 } 336 337 mtu = IPV6_MIN_MTU; 338 rcu_read_lock(); 339 idev = __in6_dev_get(dst->dev); 340 if (idev) 341 mtu = idev->cnf.mtu6; 342 rcu_read_unlock(); 343 344 return mtu; 345 } 346 347 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 348 { 349 if (skb->len <= mtu) 350 return false; 351 352 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 353 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 354 return true; 355 356 if (skb->ignore_df) 357 return false; 358 359 if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) 360 return false; 361 362 return true; 363 } 364 365 int ip6_forward(struct sk_buff *skb) 366 { 367 struct dst_entry *dst = skb_dst(skb); 368 struct ipv6hdr *hdr = ipv6_hdr(skb); 369 struct inet6_skb_parm *opt = IP6CB(skb); 370 struct net *net = dev_net(dst->dev); 371 u32 mtu; 372 373 if (net->ipv6.devconf_all->forwarding == 0) 374 goto error; 375 376 if (skb->pkt_type != PACKET_HOST) 377 goto drop; 378 379 if (skb_warn_if_lro(skb)) 380 goto drop; 381 382 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 383 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 384 IPSTATS_MIB_INDISCARDS); 385 goto drop; 386 } 387 388 skb_forward_csum(skb); 389 390 /* 391 * We DO NOT make any processing on 392 * RA packets, pushing them to user level AS IS 393 * without ane WARRANTY that application will be able 394 * to interpret them. The reason is that we 395 * cannot make anything clever here. 396 * 397 * We are not end-node, so that if packet contains 398 * AH/ESP, we cannot make anything. 399 * Defragmentation also would be mistake, RA packets 400 * cannot be fragmented, because there is no warranty 401 * that different fragments will go along one path. --ANK 402 */ 403 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 404 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 405 return 0; 406 } 407 408 /* 409 * check and decrement ttl 410 */ 411 if (hdr->hop_limit <= 1) { 412 /* Force OUTPUT device used as source address */ 413 skb->dev = dst->dev; 414 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 415 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 416 IPSTATS_MIB_INHDRERRORS); 417 418 kfree_skb(skb); 419 return -ETIMEDOUT; 420 } 421 422 /* XXX: idev->cnf.proxy_ndp? */ 423 if (net->ipv6.devconf_all->proxy_ndp && 424 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 425 int proxied = ip6_forward_proxy_check(skb); 426 if (proxied > 0) 427 return ip6_input(skb); 428 else if (proxied < 0) { 429 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 430 IPSTATS_MIB_INDISCARDS); 431 goto drop; 432 } 433 } 434 435 if (!xfrm6_route_forward(skb)) { 436 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 437 IPSTATS_MIB_INDISCARDS); 438 goto drop; 439 } 440 dst = skb_dst(skb); 441 442 /* IPv6 specs say nothing about it, but it is clear that we cannot 443 send redirects to source routed frames. 444 We don't send redirects to frames decapsulated from IPsec. 445 */ 446 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) { 447 struct in6_addr *target = NULL; 448 struct inet_peer *peer; 449 struct rt6_info *rt; 450 451 /* 452 * incoming and outgoing devices are the same 453 * send a redirect. 454 */ 455 456 rt = (struct rt6_info *) dst; 457 if (rt->rt6i_flags & RTF_GATEWAY) 458 target = &rt->rt6i_gateway; 459 else 460 target = &hdr->daddr; 461 462 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1); 463 464 /* Limit redirects both by destination (here) 465 and by source (inside ndisc_send_redirect) 466 */ 467 if (inet_peer_xrlim_allow(peer, 1*HZ)) 468 ndisc_send_redirect(skb, target); 469 if (peer) 470 inet_putpeer(peer); 471 } else { 472 int addrtype = ipv6_addr_type(&hdr->saddr); 473 474 /* This check is security critical. */ 475 if (addrtype == IPV6_ADDR_ANY || 476 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 477 goto error; 478 if (addrtype & IPV6_ADDR_LINKLOCAL) { 479 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 480 ICMPV6_NOT_NEIGHBOUR, 0); 481 goto error; 482 } 483 } 484 485 mtu = ip6_dst_mtu_forward(dst); 486 if (mtu < IPV6_MIN_MTU) 487 mtu = IPV6_MIN_MTU; 488 489 if (ip6_pkt_too_big(skb, mtu)) { 490 /* Again, force OUTPUT device used as source address */ 491 skb->dev = dst->dev; 492 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 493 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 494 IPSTATS_MIB_INTOOBIGERRORS); 495 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 496 IPSTATS_MIB_FRAGFAILS); 497 kfree_skb(skb); 498 return -EMSGSIZE; 499 } 500 501 if (skb_cow(skb, dst->dev->hard_header_len)) { 502 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), 503 IPSTATS_MIB_OUTDISCARDS); 504 goto drop; 505 } 506 507 hdr = ipv6_hdr(skb); 508 509 /* Mangling hops number delayed to point after skb COW */ 510 511 hdr->hop_limit--; 512 513 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 514 IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 515 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, NULL, skb, 516 skb->dev, dst->dev, 517 ip6_forward_finish); 518 519 error: 520 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); 521 drop: 522 kfree_skb(skb); 523 return -EINVAL; 524 } 525 526 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 527 { 528 to->pkt_type = from->pkt_type; 529 to->priority = from->priority; 530 to->protocol = from->protocol; 531 skb_dst_drop(to); 532 skb_dst_set(to, dst_clone(skb_dst(from))); 533 to->dev = from->dev; 534 to->mark = from->mark; 535 536 #ifdef CONFIG_NET_SCHED 537 to->tc_index = from->tc_index; 538 #endif 539 nf_copy(to, from); 540 skb_copy_secmark(to, from); 541 } 542 543 int ip6_fragment(struct sock *sk, struct sk_buff *skb, 544 int (*output)(struct sock *, struct sk_buff *)) 545 { 546 struct sk_buff *frag; 547 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 548 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ? 549 inet6_sk(skb->sk) : NULL; 550 struct ipv6hdr *tmp_hdr; 551 struct frag_hdr *fh; 552 unsigned int mtu, hlen, left, len; 553 int hroom, troom; 554 __be32 frag_id; 555 int ptr, offset = 0, err = 0; 556 u8 *prevhdr, nexthdr = 0; 557 struct net *net = dev_net(skb_dst(skb)->dev); 558 559 hlen = ip6_find_1stfragopt(skb, &prevhdr); 560 nexthdr = *prevhdr; 561 562 mtu = ip6_skb_dst_mtu(skb); 563 564 /* We must not fragment if the socket is set to force MTU discovery 565 * or if the skb it not generated by a local socket. 566 */ 567 if (unlikely(!skb->ignore_df && skb->len > mtu)) 568 goto fail_toobig; 569 570 if (IP6CB(skb)->frag_max_size) { 571 if (IP6CB(skb)->frag_max_size > mtu) 572 goto fail_toobig; 573 574 /* don't send fragments larger than what we received */ 575 mtu = IP6CB(skb)->frag_max_size; 576 if (mtu < IPV6_MIN_MTU) 577 mtu = IPV6_MIN_MTU; 578 } 579 580 if (np && np->frag_size < mtu) { 581 if (np->frag_size) 582 mtu = np->frag_size; 583 } 584 mtu -= hlen + sizeof(struct frag_hdr); 585 586 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, 587 &ipv6_hdr(skb)->saddr); 588 589 if (skb_has_frag_list(skb)) { 590 int first_len = skb_pagelen(skb); 591 struct sk_buff *frag2; 592 593 if (first_len - hlen > mtu || 594 ((first_len - hlen) & 7) || 595 skb_cloned(skb)) 596 goto slow_path; 597 598 skb_walk_frags(skb, frag) { 599 /* Correct geometry. */ 600 if (frag->len > mtu || 601 ((frag->len & 7) && frag->next) || 602 skb_headroom(frag) < hlen) 603 goto slow_path_clean; 604 605 /* Partially cloned skb? */ 606 if (skb_shared(frag)) 607 goto slow_path_clean; 608 609 BUG_ON(frag->sk); 610 if (skb->sk) { 611 frag->sk = skb->sk; 612 frag->destructor = sock_wfree; 613 } 614 skb->truesize -= frag->truesize; 615 } 616 617 err = 0; 618 offset = 0; 619 frag = skb_shinfo(skb)->frag_list; 620 skb_frag_list_init(skb); 621 /* BUILD HEADER */ 622 623 *prevhdr = NEXTHDR_FRAGMENT; 624 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 625 if (!tmp_hdr) { 626 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 627 IPSTATS_MIB_FRAGFAILS); 628 return -ENOMEM; 629 } 630 631 __skb_pull(skb, hlen); 632 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr)); 633 __skb_push(skb, hlen); 634 skb_reset_network_header(skb); 635 memcpy(skb_network_header(skb), tmp_hdr, hlen); 636 637 fh->nexthdr = nexthdr; 638 fh->reserved = 0; 639 fh->frag_off = htons(IP6_MF); 640 fh->identification = frag_id; 641 642 first_len = skb_pagelen(skb); 643 skb->data_len = first_len - skb_headlen(skb); 644 skb->len = first_len; 645 ipv6_hdr(skb)->payload_len = htons(first_len - 646 sizeof(struct ipv6hdr)); 647 648 dst_hold(&rt->dst); 649 650 for (;;) { 651 /* Prepare header of the next frame, 652 * before previous one went down. */ 653 if (frag) { 654 frag->ip_summed = CHECKSUM_NONE; 655 skb_reset_transport_header(frag); 656 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr)); 657 __skb_push(frag, hlen); 658 skb_reset_network_header(frag); 659 memcpy(skb_network_header(frag), tmp_hdr, 660 hlen); 661 offset += skb->len - hlen - sizeof(struct frag_hdr); 662 fh->nexthdr = nexthdr; 663 fh->reserved = 0; 664 fh->frag_off = htons(offset); 665 if (frag->next) 666 fh->frag_off |= htons(IP6_MF); 667 fh->identification = frag_id; 668 ipv6_hdr(frag)->payload_len = 669 htons(frag->len - 670 sizeof(struct ipv6hdr)); 671 ip6_copy_metadata(frag, skb); 672 } 673 674 err = output(sk, skb); 675 if (!err) 676 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 677 IPSTATS_MIB_FRAGCREATES); 678 679 if (err || !frag) 680 break; 681 682 skb = frag; 683 frag = skb->next; 684 skb->next = NULL; 685 } 686 687 kfree(tmp_hdr); 688 689 if (err == 0) { 690 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 691 IPSTATS_MIB_FRAGOKS); 692 ip6_rt_put(rt); 693 return 0; 694 } 695 696 kfree_skb_list(frag); 697 698 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 699 IPSTATS_MIB_FRAGFAILS); 700 ip6_rt_put(rt); 701 return err; 702 703 slow_path_clean: 704 skb_walk_frags(skb, frag2) { 705 if (frag2 == frag) 706 break; 707 frag2->sk = NULL; 708 frag2->destructor = NULL; 709 skb->truesize += frag2->truesize; 710 } 711 } 712 713 slow_path: 714 if ((skb->ip_summed == CHECKSUM_PARTIAL) && 715 skb_checksum_help(skb)) 716 goto fail; 717 718 left = skb->len - hlen; /* Space per frame */ 719 ptr = hlen; /* Where to start from */ 720 721 /* 722 * Fragment the datagram. 723 */ 724 725 *prevhdr = NEXTHDR_FRAGMENT; 726 hroom = LL_RESERVED_SPACE(rt->dst.dev); 727 troom = rt->dst.dev->needed_tailroom; 728 729 /* 730 * Keep copying data until we run out. 731 */ 732 while (left > 0) { 733 len = left; 734 /* IF: it doesn't fit, use 'mtu' - the data space left */ 735 if (len > mtu) 736 len = mtu; 737 /* IF: we are not sending up to and including the packet end 738 then align the next start on an eight byte boundary */ 739 if (len < left) { 740 len &= ~7; 741 } 742 743 /* Allocate buffer */ 744 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 745 hroom + troom, GFP_ATOMIC); 746 if (!frag) { 747 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 748 IPSTATS_MIB_FRAGFAILS); 749 err = -ENOMEM; 750 goto fail; 751 } 752 753 /* 754 * Set up data on packet 755 */ 756 757 ip6_copy_metadata(frag, skb); 758 skb_reserve(frag, hroom); 759 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 760 skb_reset_network_header(frag); 761 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 762 frag->transport_header = (frag->network_header + hlen + 763 sizeof(struct frag_hdr)); 764 765 /* 766 * Charge the memory for the fragment to any owner 767 * it might possess 768 */ 769 if (skb->sk) 770 skb_set_owner_w(frag, skb->sk); 771 772 /* 773 * Copy the packet header into the new buffer. 774 */ 775 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 776 777 /* 778 * Build fragment header. 779 */ 780 fh->nexthdr = nexthdr; 781 fh->reserved = 0; 782 fh->identification = frag_id; 783 784 /* 785 * Copy a block of the IP datagram. 786 */ 787 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag), 788 len)); 789 left -= len; 790 791 fh->frag_off = htons(offset); 792 if (left > 0) 793 fh->frag_off |= htons(IP6_MF); 794 ipv6_hdr(frag)->payload_len = htons(frag->len - 795 sizeof(struct ipv6hdr)); 796 797 ptr += len; 798 offset += len; 799 800 /* 801 * Put this fragment into the sending queue. 802 */ 803 err = output(sk, frag); 804 if (err) 805 goto fail; 806 807 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 808 IPSTATS_MIB_FRAGCREATES); 809 } 810 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 811 IPSTATS_MIB_FRAGOKS); 812 consume_skb(skb); 813 return err; 814 815 fail_toobig: 816 if (skb->sk && dst_allfrag(skb_dst(skb))) 817 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 818 819 skb->dev = skb_dst(skb)->dev; 820 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 821 err = -EMSGSIZE; 822 823 fail: 824 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 825 IPSTATS_MIB_FRAGFAILS); 826 kfree_skb(skb); 827 return err; 828 } 829 830 static inline int ip6_rt_check(const struct rt6key *rt_key, 831 const struct in6_addr *fl_addr, 832 const struct in6_addr *addr_cache) 833 { 834 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 835 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache)); 836 } 837 838 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 839 struct dst_entry *dst, 840 const struct flowi6 *fl6) 841 { 842 struct ipv6_pinfo *np = inet6_sk(sk); 843 struct rt6_info *rt; 844 845 if (!dst) 846 goto out; 847 848 if (dst->ops->family != AF_INET6) { 849 dst_release(dst); 850 return NULL; 851 } 852 853 rt = (struct rt6_info *)dst; 854 /* Yes, checking route validity in not connected 855 * case is not very simple. Take into account, 856 * that we do not support routing by source, TOS, 857 * and MSG_DONTROUTE --ANK (980726) 858 * 859 * 1. ip6_rt_check(): If route was host route, 860 * check that cached destination is current. 861 * If it is network route, we still may 862 * check its validity using saved pointer 863 * to the last used address: daddr_cache. 864 * We do not want to save whole address now, 865 * (because main consumer of this service 866 * is tcp, which has not this problem), 867 * so that the last trick works only on connected 868 * sockets. 869 * 2. oif also should be the same. 870 */ 871 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 872 #ifdef CONFIG_IPV6_SUBTREES 873 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 874 #endif 875 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 876 dst_release(dst); 877 dst = NULL; 878 } 879 880 out: 881 return dst; 882 } 883 884 static int ip6_dst_lookup_tail(struct sock *sk, 885 struct dst_entry **dst, struct flowi6 *fl6) 886 { 887 struct net *net = sock_net(sk); 888 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 889 struct neighbour *n; 890 struct rt6_info *rt; 891 #endif 892 int err; 893 894 /* The correct way to handle this would be to do 895 * ip6_route_get_saddr, and then ip6_route_output; however, 896 * the route-specific preferred source forces the 897 * ip6_route_output call _before_ ip6_route_get_saddr. 898 * 899 * In source specific routing (no src=any default route), 900 * ip6_route_output will fail given src=any saddr, though, so 901 * that's why we try it again later. 902 */ 903 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) { 904 struct rt6_info *rt; 905 bool had_dst = *dst != NULL; 906 907 if (!had_dst) 908 *dst = ip6_route_output(net, sk, fl6); 909 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst; 910 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 911 sk ? inet6_sk(sk)->srcprefs : 0, 912 &fl6->saddr); 913 if (err) 914 goto out_err_release; 915 916 /* If we had an erroneous initial result, pretend it 917 * never existed and let the SA-enabled version take 918 * over. 919 */ 920 if (!had_dst && (*dst)->error) { 921 dst_release(*dst); 922 *dst = NULL; 923 } 924 } 925 926 if (!*dst) 927 *dst = ip6_route_output(net, sk, fl6); 928 929 err = (*dst)->error; 930 if (err) 931 goto out_err_release; 932 933 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 934 /* 935 * Here if the dst entry we've looked up 936 * has a neighbour entry that is in the INCOMPLETE 937 * state and the src address from the flow is 938 * marked as OPTIMISTIC, we release the found 939 * dst entry and replace it instead with the 940 * dst entry of the nexthop router 941 */ 942 rt = (struct rt6_info *) *dst; 943 rcu_read_lock_bh(); 944 n = __ipv6_neigh_lookup_noref(rt->dst.dev, 945 rt6_nexthop(rt, &fl6->daddr)); 946 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 947 rcu_read_unlock_bh(); 948 949 if (err) { 950 struct inet6_ifaddr *ifp; 951 struct flowi6 fl_gw6; 952 int redirect; 953 954 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 955 (*dst)->dev, 1); 956 957 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 958 if (ifp) 959 in6_ifa_put(ifp); 960 961 if (redirect) { 962 /* 963 * We need to get the dst entry for the 964 * default router instead 965 */ 966 dst_release(*dst); 967 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 968 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 969 *dst = ip6_route_output(net, sk, &fl_gw6); 970 err = (*dst)->error; 971 if (err) 972 goto out_err_release; 973 } 974 } 975 #endif 976 977 return 0; 978 979 out_err_release: 980 if (err == -ENETUNREACH) 981 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 982 dst_release(*dst); 983 *dst = NULL; 984 return err; 985 } 986 987 /** 988 * ip6_dst_lookup - perform route lookup on flow 989 * @sk: socket which provides route info 990 * @dst: pointer to dst_entry * for result 991 * @fl6: flow to lookup 992 * 993 * This function performs a route lookup on the given flow. 994 * 995 * It returns zero on success, or a standard errno code on error. 996 */ 997 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6) 998 { 999 *dst = NULL; 1000 return ip6_dst_lookup_tail(sk, dst, fl6); 1001 } 1002 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 1003 1004 /** 1005 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 1006 * @sk: socket which provides route info 1007 * @fl6: flow to lookup 1008 * @final_dst: final destination address for ipsec lookup 1009 * 1010 * This function performs a route lookup on the given flow. 1011 * 1012 * It returns a valid dst pointer on success, or a pointer encoded 1013 * error code. 1014 */ 1015 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1016 const struct in6_addr *final_dst) 1017 { 1018 struct dst_entry *dst = NULL; 1019 int err; 1020 1021 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1022 if (err) 1023 return ERR_PTR(err); 1024 if (final_dst) 1025 fl6->daddr = *final_dst; 1026 1027 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1028 } 1029 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1030 1031 /** 1032 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1033 * @sk: socket which provides the dst cache and route info 1034 * @fl6: flow to lookup 1035 * @final_dst: final destination address for ipsec lookup 1036 * 1037 * This function performs a route lookup on the given flow with the 1038 * possibility of using the cached route in the socket if it is valid. 1039 * It will take the socket dst lock when operating on the dst cache. 1040 * As a result, this function can only be used in process context. 1041 * 1042 * It returns a valid dst pointer on success, or a pointer encoded 1043 * error code. 1044 */ 1045 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1046 const struct in6_addr *final_dst) 1047 { 1048 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1049 int err; 1050 1051 dst = ip6_sk_dst_check(sk, dst, fl6); 1052 1053 err = ip6_dst_lookup_tail(sk, &dst, fl6); 1054 if (err) 1055 return ERR_PTR(err); 1056 if (final_dst) 1057 fl6->daddr = *final_dst; 1058 1059 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1060 } 1061 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1062 1063 static inline int ip6_ufo_append_data(struct sock *sk, 1064 struct sk_buff_head *queue, 1065 int getfrag(void *from, char *to, int offset, int len, 1066 int odd, struct sk_buff *skb), 1067 void *from, int length, int hh_len, int fragheaderlen, 1068 int transhdrlen, int mtu, unsigned int flags, 1069 const struct flowi6 *fl6) 1070 1071 { 1072 struct sk_buff *skb; 1073 int err; 1074 1075 /* There is support for UDP large send offload by network 1076 * device, so create one single skb packet containing complete 1077 * udp datagram 1078 */ 1079 skb = skb_peek_tail(queue); 1080 if (!skb) { 1081 skb = sock_alloc_send_skb(sk, 1082 hh_len + fragheaderlen + transhdrlen + 20, 1083 (flags & MSG_DONTWAIT), &err); 1084 if (!skb) 1085 return err; 1086 1087 /* reserve space for Hardware header */ 1088 skb_reserve(skb, hh_len); 1089 1090 /* create space for UDP/IP header */ 1091 skb_put(skb, fragheaderlen + transhdrlen); 1092 1093 /* initialize network header pointer */ 1094 skb_reset_network_header(skb); 1095 1096 /* initialize protocol header pointer */ 1097 skb->transport_header = skb->network_header + fragheaderlen; 1098 1099 skb->protocol = htons(ETH_P_IPV6); 1100 skb->csum = 0; 1101 1102 __skb_queue_tail(queue, skb); 1103 } else if (skb_is_gso(skb)) { 1104 goto append; 1105 } 1106 1107 skb->ip_summed = CHECKSUM_PARTIAL; 1108 /* Specify the length of each IPv6 datagram fragment. 1109 * It has to be a multiple of 8. 1110 */ 1111 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1112 sizeof(struct frag_hdr)) & ~7; 1113 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1114 skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk), 1115 &fl6->daddr, 1116 &fl6->saddr); 1117 1118 append: 1119 return skb_append_datato_frags(sk, skb, getfrag, from, 1120 (length - transhdrlen)); 1121 } 1122 1123 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1124 gfp_t gfp) 1125 { 1126 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1127 } 1128 1129 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1130 gfp_t gfp) 1131 { 1132 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1133 } 1134 1135 static void ip6_append_data_mtu(unsigned int *mtu, 1136 int *maxfraglen, 1137 unsigned int fragheaderlen, 1138 struct sk_buff *skb, 1139 struct rt6_info *rt, 1140 unsigned int orig_mtu) 1141 { 1142 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1143 if (!skb) { 1144 /* first fragment, reserve header_len */ 1145 *mtu = orig_mtu - rt->dst.header_len; 1146 1147 } else { 1148 /* 1149 * this fragment is not first, the headers 1150 * space is regarded as data space. 1151 */ 1152 *mtu = orig_mtu; 1153 } 1154 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1155 + fragheaderlen - sizeof(struct frag_hdr); 1156 } 1157 } 1158 1159 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1160 struct inet6_cork *v6_cork, 1161 int hlimit, int tclass, struct ipv6_txoptions *opt, 1162 struct rt6_info *rt, struct flowi6 *fl6) 1163 { 1164 struct ipv6_pinfo *np = inet6_sk(sk); 1165 unsigned int mtu; 1166 1167 /* 1168 * setup for corking 1169 */ 1170 if (opt) { 1171 if (WARN_ON(v6_cork->opt)) 1172 return -EINVAL; 1173 1174 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation); 1175 if (unlikely(!v6_cork->opt)) 1176 return -ENOBUFS; 1177 1178 v6_cork->opt->tot_len = opt->tot_len; 1179 v6_cork->opt->opt_flen = opt->opt_flen; 1180 v6_cork->opt->opt_nflen = opt->opt_nflen; 1181 1182 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1183 sk->sk_allocation); 1184 if (opt->dst0opt && !v6_cork->opt->dst0opt) 1185 return -ENOBUFS; 1186 1187 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1188 sk->sk_allocation); 1189 if (opt->dst1opt && !v6_cork->opt->dst1opt) 1190 return -ENOBUFS; 1191 1192 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt, 1193 sk->sk_allocation); 1194 if (opt->hopopt && !v6_cork->opt->hopopt) 1195 return -ENOBUFS; 1196 1197 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1198 sk->sk_allocation); 1199 if (opt->srcrt && !v6_cork->opt->srcrt) 1200 return -ENOBUFS; 1201 1202 /* need source address above miyazawa*/ 1203 } 1204 dst_hold(&rt->dst); 1205 cork->base.dst = &rt->dst; 1206 cork->fl.u.ip6 = *fl6; 1207 v6_cork->hop_limit = hlimit; 1208 v6_cork->tclass = tclass; 1209 if (rt->dst.flags & DST_XFRM_TUNNEL) 1210 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1211 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1212 else 1213 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1214 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1215 if (np->frag_size < mtu) { 1216 if (np->frag_size) 1217 mtu = np->frag_size; 1218 } 1219 cork->base.fragsize = mtu; 1220 if (dst_allfrag(rt->dst.path)) 1221 cork->base.flags |= IPCORK_ALLFRAG; 1222 cork->base.length = 0; 1223 1224 return 0; 1225 } 1226 1227 static int __ip6_append_data(struct sock *sk, 1228 struct flowi6 *fl6, 1229 struct sk_buff_head *queue, 1230 struct inet_cork *cork, 1231 struct inet6_cork *v6_cork, 1232 struct page_frag *pfrag, 1233 int getfrag(void *from, char *to, int offset, 1234 int len, int odd, struct sk_buff *skb), 1235 void *from, int length, int transhdrlen, 1236 unsigned int flags, int dontfrag) 1237 { 1238 struct sk_buff *skb, *skb_prev = NULL; 1239 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1240 int exthdrlen = 0; 1241 int dst_exthdrlen = 0; 1242 int hh_len; 1243 int copy; 1244 int err; 1245 int offset = 0; 1246 __u8 tx_flags = 0; 1247 u32 tskey = 0; 1248 struct rt6_info *rt = (struct rt6_info *)cork->dst; 1249 struct ipv6_txoptions *opt = v6_cork->opt; 1250 int csummode = CHECKSUM_NONE; 1251 1252 skb = skb_peek_tail(queue); 1253 if (!skb) { 1254 exthdrlen = opt ? opt->opt_flen : 0; 1255 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1256 } 1257 1258 mtu = cork->fragsize; 1259 orig_mtu = mtu; 1260 1261 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1262 1263 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1264 (opt ? opt->opt_nflen : 0); 1265 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1266 sizeof(struct frag_hdr); 1267 1268 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 1269 unsigned int maxnonfragsize, headersize; 1270 1271 headersize = sizeof(struct ipv6hdr) + 1272 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1273 (dst_allfrag(&rt->dst) ? 1274 sizeof(struct frag_hdr) : 0) + 1275 rt->rt6i_nfheader_len; 1276 1277 if (ip6_sk_ignore_df(sk)) 1278 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1279 else 1280 maxnonfragsize = mtu; 1281 1282 /* dontfrag active */ 1283 if ((cork->length + length > mtu - headersize) && dontfrag && 1284 (sk->sk_protocol == IPPROTO_UDP || 1285 sk->sk_protocol == IPPROTO_RAW)) { 1286 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1287 sizeof(struct ipv6hdr)); 1288 goto emsgsize; 1289 } 1290 1291 if (cork->length + length > maxnonfragsize - headersize) { 1292 emsgsize: 1293 ipv6_local_error(sk, EMSGSIZE, fl6, 1294 mtu - headersize + 1295 sizeof(struct ipv6hdr)); 1296 return -EMSGSIZE; 1297 } 1298 } 1299 1300 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1301 sock_tx_timestamp(sk, &tx_flags); 1302 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1303 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1304 tskey = sk->sk_tskey++; 1305 } 1306 1307 /* If this is the first and only packet and device 1308 * supports checksum offloading, let's use it. 1309 * Use transhdrlen, same as IPv4, because partial 1310 * sums only work when transhdrlen is set. 1311 */ 1312 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1313 length + fragheaderlen < mtu && 1314 rt->dst.dev->features & NETIF_F_V6_CSUM && 1315 !exthdrlen) 1316 csummode = CHECKSUM_PARTIAL; 1317 /* 1318 * Let's try using as much space as possible. 1319 * Use MTU if total length of the message fits into the MTU. 1320 * Otherwise, we need to reserve fragment header and 1321 * fragment alignment (= 8-15 octects, in total). 1322 * 1323 * Note that we may need to "move" the data from the tail of 1324 * of the buffer to the new fragment when we split 1325 * the message. 1326 * 1327 * FIXME: It may be fragmented into multiple chunks 1328 * at once if non-fragmentable extension headers 1329 * are too large. 1330 * --yoshfuji 1331 */ 1332 1333 cork->length += length; 1334 if (((length > mtu) || 1335 (skb && skb_is_gso(skb))) && 1336 (sk->sk_protocol == IPPROTO_UDP) && 1337 (rt->dst.dev->features & NETIF_F_UFO) && 1338 (sk->sk_type == SOCK_DGRAM)) { 1339 err = ip6_ufo_append_data(sk, queue, getfrag, from, length, 1340 hh_len, fragheaderlen, 1341 transhdrlen, mtu, flags, fl6); 1342 if (err) 1343 goto error; 1344 return 0; 1345 } 1346 1347 if (!skb) 1348 goto alloc_new_skb; 1349 1350 while (length > 0) { 1351 /* Check if the remaining data fits into current packet. */ 1352 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1353 if (copy < length) 1354 copy = maxfraglen - skb->len; 1355 1356 if (copy <= 0) { 1357 char *data; 1358 unsigned int datalen; 1359 unsigned int fraglen; 1360 unsigned int fraggap; 1361 unsigned int alloclen; 1362 alloc_new_skb: 1363 /* There's no room in the current skb */ 1364 if (skb) 1365 fraggap = skb->len - maxfraglen; 1366 else 1367 fraggap = 0; 1368 /* update mtu and maxfraglen if necessary */ 1369 if (!skb || !skb_prev) 1370 ip6_append_data_mtu(&mtu, &maxfraglen, 1371 fragheaderlen, skb, rt, 1372 orig_mtu); 1373 1374 skb_prev = skb; 1375 1376 /* 1377 * If remaining data exceeds the mtu, 1378 * we know we need more fragment(s). 1379 */ 1380 datalen = length + fraggap; 1381 1382 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1383 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1384 if ((flags & MSG_MORE) && 1385 !(rt->dst.dev->features&NETIF_F_SG)) 1386 alloclen = mtu; 1387 else 1388 alloclen = datalen + fragheaderlen; 1389 1390 alloclen += dst_exthdrlen; 1391 1392 if (datalen != length + fraggap) { 1393 /* 1394 * this is not the last fragment, the trailer 1395 * space is regarded as data space. 1396 */ 1397 datalen += rt->dst.trailer_len; 1398 } 1399 1400 alloclen += rt->dst.trailer_len; 1401 fraglen = datalen + fragheaderlen; 1402 1403 /* 1404 * We just reserve space for fragment header. 1405 * Note: this may be overallocation if the message 1406 * (without MSG_MORE) fits into the MTU. 1407 */ 1408 alloclen += sizeof(struct frag_hdr); 1409 1410 if (transhdrlen) { 1411 skb = sock_alloc_send_skb(sk, 1412 alloclen + hh_len, 1413 (flags & MSG_DONTWAIT), &err); 1414 } else { 1415 skb = NULL; 1416 if (atomic_read(&sk->sk_wmem_alloc) <= 1417 2 * sk->sk_sndbuf) 1418 skb = sock_wmalloc(sk, 1419 alloclen + hh_len, 1, 1420 sk->sk_allocation); 1421 if (unlikely(!skb)) 1422 err = -ENOBUFS; 1423 } 1424 if (!skb) 1425 goto error; 1426 /* 1427 * Fill in the control structures 1428 */ 1429 skb->protocol = htons(ETH_P_IPV6); 1430 skb->ip_summed = csummode; 1431 skb->csum = 0; 1432 /* reserve for fragmentation and ipsec header */ 1433 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1434 dst_exthdrlen); 1435 1436 /* Only the initial fragment is time stamped */ 1437 skb_shinfo(skb)->tx_flags = tx_flags; 1438 tx_flags = 0; 1439 skb_shinfo(skb)->tskey = tskey; 1440 tskey = 0; 1441 1442 /* 1443 * Find where to start putting bytes 1444 */ 1445 data = skb_put(skb, fraglen); 1446 skb_set_network_header(skb, exthdrlen); 1447 data += fragheaderlen; 1448 skb->transport_header = (skb->network_header + 1449 fragheaderlen); 1450 if (fraggap) { 1451 skb->csum = skb_copy_and_csum_bits( 1452 skb_prev, maxfraglen, 1453 data + transhdrlen, fraggap, 0); 1454 skb_prev->csum = csum_sub(skb_prev->csum, 1455 skb->csum); 1456 data += fraggap; 1457 pskb_trim_unique(skb_prev, maxfraglen); 1458 } 1459 copy = datalen - transhdrlen - fraggap; 1460 1461 if (copy < 0) { 1462 err = -EINVAL; 1463 kfree_skb(skb); 1464 goto error; 1465 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1466 err = -EFAULT; 1467 kfree_skb(skb); 1468 goto error; 1469 } 1470 1471 offset += copy; 1472 length -= datalen - fraggap; 1473 transhdrlen = 0; 1474 exthdrlen = 0; 1475 dst_exthdrlen = 0; 1476 1477 /* 1478 * Put the packet on the pending queue 1479 */ 1480 __skb_queue_tail(queue, skb); 1481 continue; 1482 } 1483 1484 if (copy > length) 1485 copy = length; 1486 1487 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1488 unsigned int off; 1489 1490 off = skb->len; 1491 if (getfrag(from, skb_put(skb, copy), 1492 offset, copy, off, skb) < 0) { 1493 __skb_trim(skb, off); 1494 err = -EFAULT; 1495 goto error; 1496 } 1497 } else { 1498 int i = skb_shinfo(skb)->nr_frags; 1499 1500 err = -ENOMEM; 1501 if (!sk_page_frag_refill(sk, pfrag)) 1502 goto error; 1503 1504 if (!skb_can_coalesce(skb, i, pfrag->page, 1505 pfrag->offset)) { 1506 err = -EMSGSIZE; 1507 if (i == MAX_SKB_FRAGS) 1508 goto error; 1509 1510 __skb_fill_page_desc(skb, i, pfrag->page, 1511 pfrag->offset, 0); 1512 skb_shinfo(skb)->nr_frags = ++i; 1513 get_page(pfrag->page); 1514 } 1515 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1516 if (getfrag(from, 1517 page_address(pfrag->page) + pfrag->offset, 1518 offset, copy, skb->len, skb) < 0) 1519 goto error_efault; 1520 1521 pfrag->offset += copy; 1522 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1523 skb->len += copy; 1524 skb->data_len += copy; 1525 skb->truesize += copy; 1526 atomic_add(copy, &sk->sk_wmem_alloc); 1527 } 1528 offset += copy; 1529 length -= copy; 1530 } 1531 1532 return 0; 1533 1534 error_efault: 1535 err = -EFAULT; 1536 error: 1537 cork->length -= length; 1538 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1539 return err; 1540 } 1541 1542 int ip6_append_data(struct sock *sk, 1543 int getfrag(void *from, char *to, int offset, int len, 1544 int odd, struct sk_buff *skb), 1545 void *from, int length, int transhdrlen, int hlimit, 1546 int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6, 1547 struct rt6_info *rt, unsigned int flags, int dontfrag) 1548 { 1549 struct inet_sock *inet = inet_sk(sk); 1550 struct ipv6_pinfo *np = inet6_sk(sk); 1551 int exthdrlen; 1552 int err; 1553 1554 if (flags&MSG_PROBE) 1555 return 0; 1556 if (skb_queue_empty(&sk->sk_write_queue)) { 1557 /* 1558 * setup for corking 1559 */ 1560 err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit, 1561 tclass, opt, rt, fl6); 1562 if (err) 1563 return err; 1564 1565 exthdrlen = (opt ? opt->opt_flen : 0); 1566 length += exthdrlen; 1567 transhdrlen += exthdrlen; 1568 } else { 1569 fl6 = &inet->cork.fl.u.ip6; 1570 transhdrlen = 0; 1571 } 1572 1573 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1574 &np->cork, sk_page_frag(sk), getfrag, 1575 from, length, transhdrlen, flags, dontfrag); 1576 } 1577 EXPORT_SYMBOL_GPL(ip6_append_data); 1578 1579 static void ip6_cork_release(struct inet_cork_full *cork, 1580 struct inet6_cork *v6_cork) 1581 { 1582 if (v6_cork->opt) { 1583 kfree(v6_cork->opt->dst0opt); 1584 kfree(v6_cork->opt->dst1opt); 1585 kfree(v6_cork->opt->hopopt); 1586 kfree(v6_cork->opt->srcrt); 1587 kfree(v6_cork->opt); 1588 v6_cork->opt = NULL; 1589 } 1590 1591 if (cork->base.dst) { 1592 dst_release(cork->base.dst); 1593 cork->base.dst = NULL; 1594 cork->base.flags &= ~IPCORK_ALLFRAG; 1595 } 1596 memset(&cork->fl, 0, sizeof(cork->fl)); 1597 } 1598 1599 struct sk_buff *__ip6_make_skb(struct sock *sk, 1600 struct sk_buff_head *queue, 1601 struct inet_cork_full *cork, 1602 struct inet6_cork *v6_cork) 1603 { 1604 struct sk_buff *skb, *tmp_skb; 1605 struct sk_buff **tail_skb; 1606 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1607 struct ipv6_pinfo *np = inet6_sk(sk); 1608 struct net *net = sock_net(sk); 1609 struct ipv6hdr *hdr; 1610 struct ipv6_txoptions *opt = v6_cork->opt; 1611 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1612 struct flowi6 *fl6 = &cork->fl.u.ip6; 1613 unsigned char proto = fl6->flowi6_proto; 1614 1615 skb = __skb_dequeue(queue); 1616 if (!skb) 1617 goto out; 1618 tail_skb = &(skb_shinfo(skb)->frag_list); 1619 1620 /* move skb->data to ip header from ext header */ 1621 if (skb->data < skb_network_header(skb)) 1622 __skb_pull(skb, skb_network_offset(skb)); 1623 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1624 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1625 *tail_skb = tmp_skb; 1626 tail_skb = &(tmp_skb->next); 1627 skb->len += tmp_skb->len; 1628 skb->data_len += tmp_skb->len; 1629 skb->truesize += tmp_skb->truesize; 1630 tmp_skb->destructor = NULL; 1631 tmp_skb->sk = NULL; 1632 } 1633 1634 /* Allow local fragmentation. */ 1635 skb->ignore_df = ip6_sk_ignore_df(sk); 1636 1637 *final_dst = fl6->daddr; 1638 __skb_pull(skb, skb_network_header_len(skb)); 1639 if (opt && opt->opt_flen) 1640 ipv6_push_frag_opts(skb, opt, &proto); 1641 if (opt && opt->opt_nflen) 1642 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1643 1644 skb_push(skb, sizeof(struct ipv6hdr)); 1645 skb_reset_network_header(skb); 1646 hdr = ipv6_hdr(skb); 1647 1648 ip6_flow_hdr(hdr, v6_cork->tclass, 1649 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1650 np->autoflowlabel)); 1651 hdr->hop_limit = v6_cork->hop_limit; 1652 hdr->nexthdr = proto; 1653 hdr->saddr = fl6->saddr; 1654 hdr->daddr = *final_dst; 1655 1656 skb->priority = sk->sk_priority; 1657 skb->mark = sk->sk_mark; 1658 1659 skb_dst_set(skb, dst_clone(&rt->dst)); 1660 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1661 if (proto == IPPROTO_ICMPV6) { 1662 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1663 1664 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1665 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1666 } 1667 1668 ip6_cork_release(cork, v6_cork); 1669 out: 1670 return skb; 1671 } 1672 1673 int ip6_send_skb(struct sk_buff *skb) 1674 { 1675 struct net *net = sock_net(skb->sk); 1676 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1677 int err; 1678 1679 err = ip6_local_out(skb); 1680 if (err) { 1681 if (err > 0) 1682 err = net_xmit_errno(err); 1683 if (err) 1684 IP6_INC_STATS(net, rt->rt6i_idev, 1685 IPSTATS_MIB_OUTDISCARDS); 1686 } 1687 1688 return err; 1689 } 1690 1691 int ip6_push_pending_frames(struct sock *sk) 1692 { 1693 struct sk_buff *skb; 1694 1695 skb = ip6_finish_skb(sk); 1696 if (!skb) 1697 return 0; 1698 1699 return ip6_send_skb(skb); 1700 } 1701 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1702 1703 static void __ip6_flush_pending_frames(struct sock *sk, 1704 struct sk_buff_head *queue, 1705 struct inet_cork_full *cork, 1706 struct inet6_cork *v6_cork) 1707 { 1708 struct sk_buff *skb; 1709 1710 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1711 if (skb_dst(skb)) 1712 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1713 IPSTATS_MIB_OUTDISCARDS); 1714 kfree_skb(skb); 1715 } 1716 1717 ip6_cork_release(cork, v6_cork); 1718 } 1719 1720 void ip6_flush_pending_frames(struct sock *sk) 1721 { 1722 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1723 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1724 } 1725 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1726 1727 struct sk_buff *ip6_make_skb(struct sock *sk, 1728 int getfrag(void *from, char *to, int offset, 1729 int len, int odd, struct sk_buff *skb), 1730 void *from, int length, int transhdrlen, 1731 int hlimit, int tclass, 1732 struct ipv6_txoptions *opt, struct flowi6 *fl6, 1733 struct rt6_info *rt, unsigned int flags, 1734 int dontfrag) 1735 { 1736 struct inet_cork_full cork; 1737 struct inet6_cork v6_cork; 1738 struct sk_buff_head queue; 1739 int exthdrlen = (opt ? opt->opt_flen : 0); 1740 int err; 1741 1742 if (flags & MSG_PROBE) 1743 return NULL; 1744 1745 __skb_queue_head_init(&queue); 1746 1747 cork.base.flags = 0; 1748 cork.base.addr = 0; 1749 cork.base.opt = NULL; 1750 v6_cork.opt = NULL; 1751 err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6); 1752 if (err) 1753 return ERR_PTR(err); 1754 1755 if (dontfrag < 0) 1756 dontfrag = inet6_sk(sk)->dontfrag; 1757 1758 err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork, 1759 ¤t->task_frag, getfrag, from, 1760 length + exthdrlen, transhdrlen + exthdrlen, 1761 flags, dontfrag); 1762 if (err) { 1763 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork); 1764 return ERR_PTR(err); 1765 } 1766 1767 return __ip6_make_skb(sk, &queue, &cork, &v6_cork); 1768 } 1769