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/bpf-cgroup.h> 43 #include <linux/netfilter.h> 44 #include <linux/netfilter_ipv6.h> 45 46 #include <net/sock.h> 47 #include <net/snmp.h> 48 49 #include <net/ipv6.h> 50 #include <net/ndisc.h> 51 #include <net/protocol.h> 52 #include <net/ip6_route.h> 53 #include <net/addrconf.h> 54 #include <net/rawv6.h> 55 #include <net/icmp.h> 56 #include <net/xfrm.h> 57 #include <net/checksum.h> 58 #include <linux/mroute6.h> 59 #include <net/l3mdev.h> 60 #include <net/lwtunnel.h> 61 62 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) 63 { 64 struct dst_entry *dst = skb_dst(skb); 65 struct net_device *dev = dst->dev; 66 struct neighbour *neigh; 67 struct in6_addr *nexthop; 68 int ret; 69 70 skb->protocol = htons(ETH_P_IPV6); 71 skb->dev = dev; 72 73 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { 74 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 75 76 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) && 77 ((mroute6_socket(net, skb) && 78 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 79 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, 80 &ipv6_hdr(skb)->saddr))) { 81 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 82 83 /* Do not check for IFF_ALLMULTI; multicast routing 84 is not supported in any case. 85 */ 86 if (newskb) 87 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 88 net, sk, newskb, NULL, newskb->dev, 89 dev_loopback_xmit); 90 91 if (ipv6_hdr(skb)->hop_limit == 0) { 92 IP6_INC_STATS(net, idev, 93 IPSTATS_MIB_OUTDISCARDS); 94 kfree_skb(skb); 95 return 0; 96 } 97 } 98 99 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len); 100 101 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <= 102 IPV6_ADDR_SCOPE_NODELOCAL && 103 !(dev->flags & IFF_LOOPBACK)) { 104 kfree_skb(skb); 105 return 0; 106 } 107 } 108 109 if (lwtunnel_xmit_redirect(dst->lwtstate)) { 110 int res = lwtunnel_xmit(skb); 111 112 if (res < 0 || res == LWTUNNEL_XMIT_DONE) 113 return res; 114 } 115 116 rcu_read_lock_bh(); 117 nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr); 118 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop); 119 if (unlikely(!neigh)) 120 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false); 121 if (!IS_ERR(neigh)) { 122 ret = dst_neigh_output(dst, neigh, skb); 123 rcu_read_unlock_bh(); 124 return ret; 125 } 126 rcu_read_unlock_bh(); 127 128 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 129 kfree_skb(skb); 130 return -EINVAL; 131 } 132 133 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) 134 { 135 int ret; 136 137 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); 138 if (ret) { 139 kfree_skb(skb); 140 return ret; 141 } 142 143 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || 144 dst_allfrag(skb_dst(skb)) || 145 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) 146 return ip6_fragment(net, sk, skb, ip6_finish_output2); 147 else 148 return ip6_finish_output2(net, sk, skb); 149 } 150 151 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 152 { 153 struct net_device *dev = skb_dst(skb)->dev; 154 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 155 156 if (unlikely(idev->cnf.disable_ipv6)) { 157 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 158 kfree_skb(skb); 159 return 0; 160 } 161 162 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 163 net, sk, skb, NULL, dev, 164 ip6_finish_output, 165 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 166 } 167 168 /* 169 * xmit an sk_buff (used by TCP, SCTP and DCCP) 170 * Note : socket lock is not held for SYNACK packets, but might be modified 171 * by calls to skb_set_owner_w() and ipv6_local_error(), 172 * which are using proper atomic operations or spinlocks. 173 */ 174 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 175 struct ipv6_txoptions *opt, int tclass) 176 { 177 struct net *net = sock_net(sk); 178 const struct ipv6_pinfo *np = inet6_sk(sk); 179 struct in6_addr *first_hop = &fl6->daddr; 180 struct dst_entry *dst = skb_dst(skb); 181 struct ipv6hdr *hdr; 182 u8 proto = fl6->flowi6_proto; 183 int seg_len = skb->len; 184 int hlimit = -1; 185 u32 mtu; 186 187 if (opt) { 188 unsigned int head_room; 189 190 /* First: exthdrs may take lots of space (~8K for now) 191 MAX_HEADER is not enough. 192 */ 193 head_room = opt->opt_nflen + opt->opt_flen; 194 seg_len += head_room; 195 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 196 197 if (skb_headroom(skb) < head_room) { 198 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 199 if (!skb2) { 200 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 201 IPSTATS_MIB_OUTDISCARDS); 202 kfree_skb(skb); 203 return -ENOBUFS; 204 } 205 consume_skb(skb); 206 skb = skb2; 207 /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically, 208 * it is safe to call in our context (socket lock not held) 209 */ 210 skb_set_owner_w(skb, (struct sock *)sk); 211 } 212 if (opt->opt_flen) 213 ipv6_push_frag_opts(skb, opt, &proto); 214 if (opt->opt_nflen) 215 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop, 216 &fl6->saddr); 217 } 218 219 skb_push(skb, sizeof(struct ipv6hdr)); 220 skb_reset_network_header(skb); 221 hdr = ipv6_hdr(skb); 222 223 /* 224 * Fill in the IPv6 header 225 */ 226 if (np) 227 hlimit = np->hop_limit; 228 if (hlimit < 0) 229 hlimit = ip6_dst_hoplimit(dst); 230 231 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 232 np->autoflowlabel, fl6)); 233 234 hdr->payload_len = htons(seg_len); 235 hdr->nexthdr = proto; 236 hdr->hop_limit = hlimit; 237 238 hdr->saddr = fl6->saddr; 239 hdr->daddr = *first_hop; 240 241 skb->protocol = htons(ETH_P_IPV6); 242 skb->priority = sk->sk_priority; 243 skb->mark = sk->sk_mark; 244 245 mtu = dst_mtu(dst); 246 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 247 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 248 IPSTATS_MIB_OUT, skb->len); 249 250 /* if egress device is enslaved to an L3 master device pass the 251 * skb to its handler for processing 252 */ 253 skb = l3mdev_ip6_out((struct sock *)sk, skb); 254 if (unlikely(!skb)) 255 return 0; 256 257 /* hooks should never assume socket lock is held. 258 * we promote our socket to non const 259 */ 260 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 261 net, (struct sock *)sk, skb, NULL, dst->dev, 262 dst_output); 263 } 264 265 skb->dev = dst->dev; 266 /* ipv6_local_error() does not require socket lock, 267 * we promote our socket to non const 268 */ 269 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu); 270 271 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 272 kfree_skb(skb); 273 return -EMSGSIZE; 274 } 275 EXPORT_SYMBOL(ip6_xmit); 276 277 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 278 { 279 struct ip6_ra_chain *ra; 280 struct sock *last = NULL; 281 282 read_lock(&ip6_ra_lock); 283 for (ra = ip6_ra_chain; ra; ra = ra->next) { 284 struct sock *sk = ra->sk; 285 if (sk && ra->sel == sel && 286 (!sk->sk_bound_dev_if || 287 sk->sk_bound_dev_if == skb->dev->ifindex)) { 288 if (last) { 289 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 290 if (skb2) 291 rawv6_rcv(last, skb2); 292 } 293 last = sk; 294 } 295 } 296 297 if (last) { 298 rawv6_rcv(last, skb); 299 read_unlock(&ip6_ra_lock); 300 return 1; 301 } 302 read_unlock(&ip6_ra_lock); 303 return 0; 304 } 305 306 static int ip6_forward_proxy_check(struct sk_buff *skb) 307 { 308 struct ipv6hdr *hdr = ipv6_hdr(skb); 309 u8 nexthdr = hdr->nexthdr; 310 __be16 frag_off; 311 int offset; 312 313 if (ipv6_ext_hdr(nexthdr)) { 314 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 315 if (offset < 0) 316 return 0; 317 } else 318 offset = sizeof(struct ipv6hdr); 319 320 if (nexthdr == IPPROTO_ICMPV6) { 321 struct icmp6hdr *icmp6; 322 323 if (!pskb_may_pull(skb, (skb_network_header(skb) + 324 offset + 1 - skb->data))) 325 return 0; 326 327 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 328 329 switch (icmp6->icmp6_type) { 330 case NDISC_ROUTER_SOLICITATION: 331 case NDISC_ROUTER_ADVERTISEMENT: 332 case NDISC_NEIGHBOUR_SOLICITATION: 333 case NDISC_NEIGHBOUR_ADVERTISEMENT: 334 case NDISC_REDIRECT: 335 /* For reaction involving unicast neighbor discovery 336 * message destined to the proxied address, pass it to 337 * input function. 338 */ 339 return 1; 340 default: 341 break; 342 } 343 } 344 345 /* 346 * The proxying router can't forward traffic sent to a link-local 347 * address, so signal the sender and discard the packet. This 348 * behavior is clarified by the MIPv6 specification. 349 */ 350 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 351 dst_link_failure(skb); 352 return -1; 353 } 354 355 return 0; 356 } 357 358 static inline int ip6_forward_finish(struct net *net, struct sock *sk, 359 struct sk_buff *skb) 360 { 361 return dst_output(net, sk, skb); 362 } 363 364 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst) 365 { 366 unsigned int mtu; 367 struct inet6_dev *idev; 368 369 if (dst_metric_locked(dst, RTAX_MTU)) { 370 mtu = dst_metric_raw(dst, RTAX_MTU); 371 if (mtu) 372 return mtu; 373 } 374 375 mtu = IPV6_MIN_MTU; 376 rcu_read_lock(); 377 idev = __in6_dev_get(dst->dev); 378 if (idev) 379 mtu = idev->cnf.mtu6; 380 rcu_read_unlock(); 381 382 return mtu; 383 } 384 385 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 386 { 387 if (skb->len <= mtu) 388 return false; 389 390 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 391 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 392 return true; 393 394 if (skb->ignore_df) 395 return false; 396 397 if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu)) 398 return false; 399 400 return true; 401 } 402 403 int ip6_forward(struct sk_buff *skb) 404 { 405 struct dst_entry *dst = skb_dst(skb); 406 struct ipv6hdr *hdr = ipv6_hdr(skb); 407 struct inet6_skb_parm *opt = IP6CB(skb); 408 struct net *net = dev_net(dst->dev); 409 u32 mtu; 410 411 if (net->ipv6.devconf_all->forwarding == 0) 412 goto error; 413 414 if (skb->pkt_type != PACKET_HOST) 415 goto drop; 416 417 if (unlikely(skb->sk)) 418 goto drop; 419 420 if (skb_warn_if_lro(skb)) 421 goto drop; 422 423 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 424 __IP6_INC_STATS(net, ip6_dst_idev(dst), 425 IPSTATS_MIB_INDISCARDS); 426 goto drop; 427 } 428 429 skb_forward_csum(skb); 430 431 /* 432 * We DO NOT make any processing on 433 * RA packets, pushing them to user level AS IS 434 * without ane WARRANTY that application will be able 435 * to interpret them. The reason is that we 436 * cannot make anything clever here. 437 * 438 * We are not end-node, so that if packet contains 439 * AH/ESP, we cannot make anything. 440 * Defragmentation also would be mistake, RA packets 441 * cannot be fragmented, because there is no warranty 442 * that different fragments will go along one path. --ANK 443 */ 444 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 445 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 446 return 0; 447 } 448 449 /* 450 * check and decrement ttl 451 */ 452 if (hdr->hop_limit <= 1) { 453 /* Force OUTPUT device used as source address */ 454 skb->dev = dst->dev; 455 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 456 __IP6_INC_STATS(net, ip6_dst_idev(dst), 457 IPSTATS_MIB_INHDRERRORS); 458 459 kfree_skb(skb); 460 return -ETIMEDOUT; 461 } 462 463 /* XXX: idev->cnf.proxy_ndp? */ 464 if (net->ipv6.devconf_all->proxy_ndp && 465 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 466 int proxied = ip6_forward_proxy_check(skb); 467 if (proxied > 0) 468 return ip6_input(skb); 469 else if (proxied < 0) { 470 __IP6_INC_STATS(net, ip6_dst_idev(dst), 471 IPSTATS_MIB_INDISCARDS); 472 goto drop; 473 } 474 } 475 476 if (!xfrm6_route_forward(skb)) { 477 __IP6_INC_STATS(net, ip6_dst_idev(dst), 478 IPSTATS_MIB_INDISCARDS); 479 goto drop; 480 } 481 dst = skb_dst(skb); 482 483 /* IPv6 specs say nothing about it, but it is clear that we cannot 484 send redirects to source routed frames. 485 We don't send redirects to frames decapsulated from IPsec. 486 */ 487 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) { 488 struct in6_addr *target = NULL; 489 struct inet_peer *peer; 490 struct rt6_info *rt; 491 492 /* 493 * incoming and outgoing devices are the same 494 * send a redirect. 495 */ 496 497 rt = (struct rt6_info *) dst; 498 if (rt->rt6i_flags & RTF_GATEWAY) 499 target = &rt->rt6i_gateway; 500 else 501 target = &hdr->daddr; 502 503 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1); 504 505 /* Limit redirects both by destination (here) 506 and by source (inside ndisc_send_redirect) 507 */ 508 if (inet_peer_xrlim_allow(peer, 1*HZ)) 509 ndisc_send_redirect(skb, target); 510 if (peer) 511 inet_putpeer(peer); 512 } else { 513 int addrtype = ipv6_addr_type(&hdr->saddr); 514 515 /* This check is security critical. */ 516 if (addrtype == IPV6_ADDR_ANY || 517 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 518 goto error; 519 if (addrtype & IPV6_ADDR_LINKLOCAL) { 520 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 521 ICMPV6_NOT_NEIGHBOUR, 0); 522 goto error; 523 } 524 } 525 526 mtu = ip6_dst_mtu_forward(dst); 527 if (mtu < IPV6_MIN_MTU) 528 mtu = IPV6_MIN_MTU; 529 530 if (ip6_pkt_too_big(skb, mtu)) { 531 /* Again, force OUTPUT device used as source address */ 532 skb->dev = dst->dev; 533 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 534 __IP6_INC_STATS(net, ip6_dst_idev(dst), 535 IPSTATS_MIB_INTOOBIGERRORS); 536 __IP6_INC_STATS(net, ip6_dst_idev(dst), 537 IPSTATS_MIB_FRAGFAILS); 538 kfree_skb(skb); 539 return -EMSGSIZE; 540 } 541 542 if (skb_cow(skb, dst->dev->hard_header_len)) { 543 __IP6_INC_STATS(net, ip6_dst_idev(dst), 544 IPSTATS_MIB_OUTDISCARDS); 545 goto drop; 546 } 547 548 hdr = ipv6_hdr(skb); 549 550 /* Mangling hops number delayed to point after skb COW */ 551 552 hdr->hop_limit--; 553 554 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 555 __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 556 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, 557 net, NULL, skb, skb->dev, dst->dev, 558 ip6_forward_finish); 559 560 error: 561 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); 562 drop: 563 kfree_skb(skb); 564 return -EINVAL; 565 } 566 567 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 568 { 569 to->pkt_type = from->pkt_type; 570 to->priority = from->priority; 571 to->protocol = from->protocol; 572 skb_dst_drop(to); 573 skb_dst_set(to, dst_clone(skb_dst(from))); 574 to->dev = from->dev; 575 to->mark = from->mark; 576 577 #ifdef CONFIG_NET_SCHED 578 to->tc_index = from->tc_index; 579 #endif 580 nf_copy(to, from); 581 skb_copy_secmark(to, from); 582 } 583 584 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, 585 int (*output)(struct net *, struct sock *, struct sk_buff *)) 586 { 587 struct sk_buff *frag; 588 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 589 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ? 590 inet6_sk(skb->sk) : NULL; 591 struct ipv6hdr *tmp_hdr; 592 struct frag_hdr *fh; 593 unsigned int mtu, hlen, left, len; 594 int hroom, troom; 595 __be32 frag_id; 596 int ptr, offset = 0, err = 0; 597 u8 *prevhdr, nexthdr = 0; 598 599 hlen = ip6_find_1stfragopt(skb, &prevhdr); 600 nexthdr = *prevhdr; 601 602 mtu = ip6_skb_dst_mtu(skb); 603 604 /* We must not fragment if the socket is set to force MTU discovery 605 * or if the skb it not generated by a local socket. 606 */ 607 if (unlikely(!skb->ignore_df && skb->len > mtu)) 608 goto fail_toobig; 609 610 if (IP6CB(skb)->frag_max_size) { 611 if (IP6CB(skb)->frag_max_size > mtu) 612 goto fail_toobig; 613 614 /* don't send fragments larger than what we received */ 615 mtu = IP6CB(skb)->frag_max_size; 616 if (mtu < IPV6_MIN_MTU) 617 mtu = IPV6_MIN_MTU; 618 } 619 620 if (np && np->frag_size < mtu) { 621 if (np->frag_size) 622 mtu = np->frag_size; 623 } 624 if (mtu < hlen + sizeof(struct frag_hdr) + 8) 625 goto fail_toobig; 626 mtu -= hlen + sizeof(struct frag_hdr); 627 628 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, 629 &ipv6_hdr(skb)->saddr); 630 631 if (skb->ip_summed == CHECKSUM_PARTIAL && 632 (err = skb_checksum_help(skb))) 633 goto fail; 634 635 hroom = LL_RESERVED_SPACE(rt->dst.dev); 636 if (skb_has_frag_list(skb)) { 637 unsigned int first_len = skb_pagelen(skb); 638 struct sk_buff *frag2; 639 640 if (first_len - hlen > mtu || 641 ((first_len - hlen) & 7) || 642 skb_cloned(skb) || 643 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr))) 644 goto slow_path; 645 646 skb_walk_frags(skb, frag) { 647 /* Correct geometry. */ 648 if (frag->len > mtu || 649 ((frag->len & 7) && frag->next) || 650 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr))) 651 goto slow_path_clean; 652 653 /* Partially cloned skb? */ 654 if (skb_shared(frag)) 655 goto slow_path_clean; 656 657 BUG_ON(frag->sk); 658 if (skb->sk) { 659 frag->sk = skb->sk; 660 frag->destructor = sock_wfree; 661 } 662 skb->truesize -= frag->truesize; 663 } 664 665 err = 0; 666 offset = 0; 667 /* BUILD HEADER */ 668 669 *prevhdr = NEXTHDR_FRAGMENT; 670 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 671 if (!tmp_hdr) { 672 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 673 IPSTATS_MIB_FRAGFAILS); 674 err = -ENOMEM; 675 goto fail; 676 } 677 frag = skb_shinfo(skb)->frag_list; 678 skb_frag_list_init(skb); 679 680 __skb_pull(skb, hlen); 681 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr)); 682 __skb_push(skb, hlen); 683 skb_reset_network_header(skb); 684 memcpy(skb_network_header(skb), tmp_hdr, hlen); 685 686 fh->nexthdr = nexthdr; 687 fh->reserved = 0; 688 fh->frag_off = htons(IP6_MF); 689 fh->identification = frag_id; 690 691 first_len = skb_pagelen(skb); 692 skb->data_len = first_len - skb_headlen(skb); 693 skb->len = first_len; 694 ipv6_hdr(skb)->payload_len = htons(first_len - 695 sizeof(struct ipv6hdr)); 696 697 dst_hold(&rt->dst); 698 699 for (;;) { 700 /* Prepare header of the next frame, 701 * before previous one went down. */ 702 if (frag) { 703 frag->ip_summed = CHECKSUM_NONE; 704 skb_reset_transport_header(frag); 705 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr)); 706 __skb_push(frag, hlen); 707 skb_reset_network_header(frag); 708 memcpy(skb_network_header(frag), tmp_hdr, 709 hlen); 710 offset += skb->len - hlen - sizeof(struct frag_hdr); 711 fh->nexthdr = nexthdr; 712 fh->reserved = 0; 713 fh->frag_off = htons(offset); 714 if (frag->next) 715 fh->frag_off |= htons(IP6_MF); 716 fh->identification = frag_id; 717 ipv6_hdr(frag)->payload_len = 718 htons(frag->len - 719 sizeof(struct ipv6hdr)); 720 ip6_copy_metadata(frag, skb); 721 } 722 723 err = output(net, sk, skb); 724 if (!err) 725 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 726 IPSTATS_MIB_FRAGCREATES); 727 728 if (err || !frag) 729 break; 730 731 skb = frag; 732 frag = skb->next; 733 skb->next = NULL; 734 } 735 736 kfree(tmp_hdr); 737 738 if (err == 0) { 739 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 740 IPSTATS_MIB_FRAGOKS); 741 ip6_rt_put(rt); 742 return 0; 743 } 744 745 kfree_skb_list(frag); 746 747 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 748 IPSTATS_MIB_FRAGFAILS); 749 ip6_rt_put(rt); 750 return err; 751 752 slow_path_clean: 753 skb_walk_frags(skb, frag2) { 754 if (frag2 == frag) 755 break; 756 frag2->sk = NULL; 757 frag2->destructor = NULL; 758 skb->truesize += frag2->truesize; 759 } 760 } 761 762 slow_path: 763 left = skb->len - hlen; /* Space per frame */ 764 ptr = hlen; /* Where to start from */ 765 766 /* 767 * Fragment the datagram. 768 */ 769 770 *prevhdr = NEXTHDR_FRAGMENT; 771 troom = rt->dst.dev->needed_tailroom; 772 773 /* 774 * Keep copying data until we run out. 775 */ 776 while (left > 0) { 777 len = left; 778 /* IF: it doesn't fit, use 'mtu' - the data space left */ 779 if (len > mtu) 780 len = mtu; 781 /* IF: we are not sending up to and including the packet end 782 then align the next start on an eight byte boundary */ 783 if (len < left) { 784 len &= ~7; 785 } 786 787 /* Allocate buffer */ 788 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 789 hroom + troom, GFP_ATOMIC); 790 if (!frag) { 791 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 792 IPSTATS_MIB_FRAGFAILS); 793 err = -ENOMEM; 794 goto fail; 795 } 796 797 /* 798 * Set up data on packet 799 */ 800 801 ip6_copy_metadata(frag, skb); 802 skb_reserve(frag, hroom); 803 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 804 skb_reset_network_header(frag); 805 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 806 frag->transport_header = (frag->network_header + hlen + 807 sizeof(struct frag_hdr)); 808 809 /* 810 * Charge the memory for the fragment to any owner 811 * it might possess 812 */ 813 if (skb->sk) 814 skb_set_owner_w(frag, skb->sk); 815 816 /* 817 * Copy the packet header into the new buffer. 818 */ 819 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 820 821 /* 822 * Build fragment header. 823 */ 824 fh->nexthdr = nexthdr; 825 fh->reserved = 0; 826 fh->identification = frag_id; 827 828 /* 829 * Copy a block of the IP datagram. 830 */ 831 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag), 832 len)); 833 left -= len; 834 835 fh->frag_off = htons(offset); 836 if (left > 0) 837 fh->frag_off |= htons(IP6_MF); 838 ipv6_hdr(frag)->payload_len = htons(frag->len - 839 sizeof(struct ipv6hdr)); 840 841 ptr += len; 842 offset += len; 843 844 /* 845 * Put this fragment into the sending queue. 846 */ 847 err = output(net, sk, frag); 848 if (err) 849 goto fail; 850 851 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 852 IPSTATS_MIB_FRAGCREATES); 853 } 854 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 855 IPSTATS_MIB_FRAGOKS); 856 consume_skb(skb); 857 return err; 858 859 fail_toobig: 860 if (skb->sk && dst_allfrag(skb_dst(skb))) 861 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 862 863 skb->dev = skb_dst(skb)->dev; 864 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 865 err = -EMSGSIZE; 866 867 fail: 868 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 869 IPSTATS_MIB_FRAGFAILS); 870 kfree_skb(skb); 871 return err; 872 } 873 874 static inline int ip6_rt_check(const struct rt6key *rt_key, 875 const struct in6_addr *fl_addr, 876 const struct in6_addr *addr_cache) 877 { 878 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 879 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache)); 880 } 881 882 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 883 struct dst_entry *dst, 884 const struct flowi6 *fl6) 885 { 886 struct ipv6_pinfo *np = inet6_sk(sk); 887 struct rt6_info *rt; 888 889 if (!dst) 890 goto out; 891 892 if (dst->ops->family != AF_INET6) { 893 dst_release(dst); 894 return NULL; 895 } 896 897 rt = (struct rt6_info *)dst; 898 /* Yes, checking route validity in not connected 899 * case is not very simple. Take into account, 900 * that we do not support routing by source, TOS, 901 * and MSG_DONTROUTE --ANK (980726) 902 * 903 * 1. ip6_rt_check(): If route was host route, 904 * check that cached destination is current. 905 * If it is network route, we still may 906 * check its validity using saved pointer 907 * to the last used address: daddr_cache. 908 * We do not want to save whole address now, 909 * (because main consumer of this service 910 * is tcp, which has not this problem), 911 * so that the last trick works only on connected 912 * sockets. 913 * 2. oif also should be the same. 914 */ 915 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 916 #ifdef CONFIG_IPV6_SUBTREES 917 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 918 #endif 919 (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) && 920 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) { 921 dst_release(dst); 922 dst = NULL; 923 } 924 925 out: 926 return dst; 927 } 928 929 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 930 struct dst_entry **dst, struct flowi6 *fl6) 931 { 932 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 933 struct neighbour *n; 934 struct rt6_info *rt; 935 #endif 936 int err; 937 int flags = 0; 938 939 /* The correct way to handle this would be to do 940 * ip6_route_get_saddr, and then ip6_route_output; however, 941 * the route-specific preferred source forces the 942 * ip6_route_output call _before_ ip6_route_get_saddr. 943 * 944 * In source specific routing (no src=any default route), 945 * ip6_route_output will fail given src=any saddr, though, so 946 * that's why we try it again later. 947 */ 948 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) { 949 struct rt6_info *rt; 950 bool had_dst = *dst != NULL; 951 952 if (!had_dst) 953 *dst = ip6_route_output(net, sk, fl6); 954 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst; 955 err = ip6_route_get_saddr(net, rt, &fl6->daddr, 956 sk ? inet6_sk(sk)->srcprefs : 0, 957 &fl6->saddr); 958 if (err) 959 goto out_err_release; 960 961 /* If we had an erroneous initial result, pretend it 962 * never existed and let the SA-enabled version take 963 * over. 964 */ 965 if (!had_dst && (*dst)->error) { 966 dst_release(*dst); 967 *dst = NULL; 968 } 969 970 if (fl6->flowi6_oif) 971 flags |= RT6_LOOKUP_F_IFACE; 972 } 973 974 if (!*dst) 975 *dst = ip6_route_output_flags(net, sk, fl6, flags); 976 977 err = (*dst)->error; 978 if (err) 979 goto out_err_release; 980 981 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 982 /* 983 * Here if the dst entry we've looked up 984 * has a neighbour entry that is in the INCOMPLETE 985 * state and the src address from the flow is 986 * marked as OPTIMISTIC, we release the found 987 * dst entry and replace it instead with the 988 * dst entry of the nexthop router 989 */ 990 rt = (struct rt6_info *) *dst; 991 rcu_read_lock_bh(); 992 n = __ipv6_neigh_lookup_noref(rt->dst.dev, 993 rt6_nexthop(rt, &fl6->daddr)); 994 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 995 rcu_read_unlock_bh(); 996 997 if (err) { 998 struct inet6_ifaddr *ifp; 999 struct flowi6 fl_gw6; 1000 int redirect; 1001 1002 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 1003 (*dst)->dev, 1); 1004 1005 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 1006 if (ifp) 1007 in6_ifa_put(ifp); 1008 1009 if (redirect) { 1010 /* 1011 * We need to get the dst entry for the 1012 * default router instead 1013 */ 1014 dst_release(*dst); 1015 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 1016 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 1017 *dst = ip6_route_output(net, sk, &fl_gw6); 1018 err = (*dst)->error; 1019 if (err) 1020 goto out_err_release; 1021 } 1022 } 1023 #endif 1024 1025 return 0; 1026 1027 out_err_release: 1028 dst_release(*dst); 1029 *dst = NULL; 1030 1031 if (err == -ENETUNREACH) 1032 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 1033 return err; 1034 } 1035 1036 /** 1037 * ip6_dst_lookup - perform route lookup on flow 1038 * @sk: socket which provides route info 1039 * @dst: pointer to dst_entry * for result 1040 * @fl6: flow to lookup 1041 * 1042 * This function performs a route lookup on the given flow. 1043 * 1044 * It returns zero on success, or a standard errno code on error. 1045 */ 1046 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst, 1047 struct flowi6 *fl6) 1048 { 1049 *dst = NULL; 1050 return ip6_dst_lookup_tail(net, sk, dst, fl6); 1051 } 1052 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 1053 1054 /** 1055 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 1056 * @sk: socket which provides route info 1057 * @fl6: flow to lookup 1058 * @final_dst: final destination address for ipsec lookup 1059 * 1060 * This function performs a route lookup on the given flow. 1061 * 1062 * It returns a valid dst pointer on success, or a pointer encoded 1063 * error code. 1064 */ 1065 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6, 1066 const struct in6_addr *final_dst) 1067 { 1068 struct dst_entry *dst = NULL; 1069 int err; 1070 1071 err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6); 1072 if (err) 1073 return ERR_PTR(err); 1074 if (final_dst) 1075 fl6->daddr = *final_dst; 1076 1077 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1078 } 1079 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1080 1081 /** 1082 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1083 * @sk: socket which provides the dst cache and route info 1084 * @fl6: flow to lookup 1085 * @final_dst: final destination address for ipsec lookup 1086 * 1087 * This function performs a route lookup on the given flow with the 1088 * possibility of using the cached route in the socket if it is valid. 1089 * It will take the socket dst lock when operating on the dst cache. 1090 * As a result, this function can only be used in process context. 1091 * 1092 * It returns a valid dst pointer on success, or a pointer encoded 1093 * error code. 1094 */ 1095 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1096 const struct in6_addr *final_dst) 1097 { 1098 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1099 1100 dst = ip6_sk_dst_check(sk, dst, fl6); 1101 if (!dst) 1102 dst = ip6_dst_lookup_flow(sk, fl6, final_dst); 1103 1104 return dst; 1105 } 1106 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1107 1108 static inline int ip6_ufo_append_data(struct sock *sk, 1109 struct sk_buff_head *queue, 1110 int getfrag(void *from, char *to, int offset, int len, 1111 int odd, struct sk_buff *skb), 1112 void *from, int length, int hh_len, int fragheaderlen, 1113 int exthdrlen, int transhdrlen, int mtu, 1114 unsigned int flags, const struct flowi6 *fl6) 1115 1116 { 1117 struct sk_buff *skb; 1118 int err; 1119 1120 /* There is support for UDP large send offload by network 1121 * device, so create one single skb packet containing complete 1122 * udp datagram 1123 */ 1124 skb = skb_peek_tail(queue); 1125 if (!skb) { 1126 skb = sock_alloc_send_skb(sk, 1127 hh_len + fragheaderlen + transhdrlen + 20, 1128 (flags & MSG_DONTWAIT), &err); 1129 if (!skb) 1130 return err; 1131 1132 /* reserve space for Hardware header */ 1133 skb_reserve(skb, hh_len); 1134 1135 /* create space for UDP/IP header */ 1136 skb_put(skb, fragheaderlen + transhdrlen); 1137 1138 /* initialize network header pointer */ 1139 skb_set_network_header(skb, exthdrlen); 1140 1141 /* initialize protocol header pointer */ 1142 skb->transport_header = skb->network_header + fragheaderlen; 1143 1144 skb->protocol = htons(ETH_P_IPV6); 1145 skb->csum = 0; 1146 1147 __skb_queue_tail(queue, skb); 1148 } else if (skb_is_gso(skb)) { 1149 goto append; 1150 } 1151 1152 skb->ip_summed = CHECKSUM_PARTIAL; 1153 /* Specify the length of each IPv6 datagram fragment. 1154 * It has to be a multiple of 8. 1155 */ 1156 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen - 1157 sizeof(struct frag_hdr)) & ~7; 1158 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1159 skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk), 1160 &fl6->daddr, 1161 &fl6->saddr); 1162 1163 append: 1164 return skb_append_datato_frags(sk, skb, getfrag, from, 1165 (length - transhdrlen)); 1166 } 1167 1168 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1169 gfp_t gfp) 1170 { 1171 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1172 } 1173 1174 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1175 gfp_t gfp) 1176 { 1177 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1178 } 1179 1180 static void ip6_append_data_mtu(unsigned int *mtu, 1181 int *maxfraglen, 1182 unsigned int fragheaderlen, 1183 struct sk_buff *skb, 1184 struct rt6_info *rt, 1185 unsigned int orig_mtu) 1186 { 1187 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1188 if (!skb) { 1189 /* first fragment, reserve header_len */ 1190 *mtu = orig_mtu - rt->dst.header_len; 1191 1192 } else { 1193 /* 1194 * this fragment is not first, the headers 1195 * space is regarded as data space. 1196 */ 1197 *mtu = orig_mtu; 1198 } 1199 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1200 + fragheaderlen - sizeof(struct frag_hdr); 1201 } 1202 } 1203 1204 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1205 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6, 1206 struct rt6_info *rt, struct flowi6 *fl6) 1207 { 1208 struct ipv6_pinfo *np = inet6_sk(sk); 1209 unsigned int mtu; 1210 struct ipv6_txoptions *opt = ipc6->opt; 1211 1212 /* 1213 * setup for corking 1214 */ 1215 if (opt) { 1216 if (WARN_ON(v6_cork->opt)) 1217 return -EINVAL; 1218 1219 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation); 1220 if (unlikely(!v6_cork->opt)) 1221 return -ENOBUFS; 1222 1223 v6_cork->opt->tot_len = opt->tot_len; 1224 v6_cork->opt->opt_flen = opt->opt_flen; 1225 v6_cork->opt->opt_nflen = opt->opt_nflen; 1226 1227 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1228 sk->sk_allocation); 1229 if (opt->dst0opt && !v6_cork->opt->dst0opt) 1230 return -ENOBUFS; 1231 1232 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1233 sk->sk_allocation); 1234 if (opt->dst1opt && !v6_cork->opt->dst1opt) 1235 return -ENOBUFS; 1236 1237 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt, 1238 sk->sk_allocation); 1239 if (opt->hopopt && !v6_cork->opt->hopopt) 1240 return -ENOBUFS; 1241 1242 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1243 sk->sk_allocation); 1244 if (opt->srcrt && !v6_cork->opt->srcrt) 1245 return -ENOBUFS; 1246 1247 /* need source address above miyazawa*/ 1248 } 1249 dst_hold(&rt->dst); 1250 cork->base.dst = &rt->dst; 1251 cork->fl.u.ip6 = *fl6; 1252 v6_cork->hop_limit = ipc6->hlimit; 1253 v6_cork->tclass = ipc6->tclass; 1254 if (rt->dst.flags & DST_XFRM_TUNNEL) 1255 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1256 rt->dst.dev->mtu : dst_mtu(&rt->dst); 1257 else 1258 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1259 rt->dst.dev->mtu : dst_mtu(rt->dst.path); 1260 if (np->frag_size < mtu) { 1261 if (np->frag_size) 1262 mtu = np->frag_size; 1263 } 1264 cork->base.fragsize = mtu; 1265 if (dst_allfrag(rt->dst.path)) 1266 cork->base.flags |= IPCORK_ALLFRAG; 1267 cork->base.length = 0; 1268 1269 return 0; 1270 } 1271 1272 static int __ip6_append_data(struct sock *sk, 1273 struct flowi6 *fl6, 1274 struct sk_buff_head *queue, 1275 struct inet_cork *cork, 1276 struct inet6_cork *v6_cork, 1277 struct page_frag *pfrag, 1278 int getfrag(void *from, char *to, int offset, 1279 int len, int odd, struct sk_buff *skb), 1280 void *from, int length, int transhdrlen, 1281 unsigned int flags, struct ipcm6_cookie *ipc6, 1282 const struct sockcm_cookie *sockc) 1283 { 1284 struct sk_buff *skb, *skb_prev = NULL; 1285 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; 1286 int exthdrlen = 0; 1287 int dst_exthdrlen = 0; 1288 int hh_len; 1289 int copy; 1290 int err; 1291 int offset = 0; 1292 __u8 tx_flags = 0; 1293 u32 tskey = 0; 1294 struct rt6_info *rt = (struct rt6_info *)cork->dst; 1295 struct ipv6_txoptions *opt = v6_cork->opt; 1296 int csummode = CHECKSUM_NONE; 1297 unsigned int maxnonfragsize, headersize; 1298 1299 skb = skb_peek_tail(queue); 1300 if (!skb) { 1301 exthdrlen = opt ? opt->opt_flen : 0; 1302 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1303 } 1304 1305 mtu = cork->fragsize; 1306 orig_mtu = mtu; 1307 1308 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1309 1310 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1311 (opt ? opt->opt_nflen : 0); 1312 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1313 sizeof(struct frag_hdr); 1314 1315 headersize = sizeof(struct ipv6hdr) + 1316 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1317 (dst_allfrag(&rt->dst) ? 1318 sizeof(struct frag_hdr) : 0) + 1319 rt->rt6i_nfheader_len; 1320 1321 if (cork->length + length > mtu - headersize && ipc6->dontfrag && 1322 (sk->sk_protocol == IPPROTO_UDP || 1323 sk->sk_protocol == IPPROTO_RAW)) { 1324 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1325 sizeof(struct ipv6hdr)); 1326 goto emsgsize; 1327 } 1328 1329 if (ip6_sk_ignore_df(sk)) 1330 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1331 else 1332 maxnonfragsize = mtu; 1333 1334 if (cork->length + length > maxnonfragsize - headersize) { 1335 emsgsize: 1336 ipv6_local_error(sk, EMSGSIZE, fl6, 1337 mtu - headersize + 1338 sizeof(struct ipv6hdr)); 1339 return -EMSGSIZE; 1340 } 1341 1342 /* CHECKSUM_PARTIAL only with no extension headers and when 1343 * we are not going to fragment 1344 */ 1345 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1346 headersize == sizeof(struct ipv6hdr) && 1347 length < mtu - headersize && 1348 !(flags & MSG_MORE) && 1349 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM)) 1350 csummode = CHECKSUM_PARTIAL; 1351 1352 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1353 sock_tx_timestamp(sk, sockc->tsflags, &tx_flags); 1354 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1355 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1356 tskey = sk->sk_tskey++; 1357 } 1358 1359 /* 1360 * Let's try using as much space as possible. 1361 * Use MTU if total length of the message fits into the MTU. 1362 * Otherwise, we need to reserve fragment header and 1363 * fragment alignment (= 8-15 octects, in total). 1364 * 1365 * Note that we may need to "move" the data from the tail of 1366 * of the buffer to the new fragment when we split 1367 * the message. 1368 * 1369 * FIXME: It may be fragmented into multiple chunks 1370 * at once if non-fragmentable extension headers 1371 * are too large. 1372 * --yoshfuji 1373 */ 1374 1375 cork->length += length; 1376 if (((length > mtu) || 1377 (skb && skb_is_gso(skb))) && 1378 (sk->sk_protocol == IPPROTO_UDP) && 1379 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && 1380 (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) { 1381 err = ip6_ufo_append_data(sk, queue, getfrag, from, length, 1382 hh_len, fragheaderlen, exthdrlen, 1383 transhdrlen, mtu, flags, fl6); 1384 if (err) 1385 goto error; 1386 return 0; 1387 } 1388 1389 if (!skb) 1390 goto alloc_new_skb; 1391 1392 while (length > 0) { 1393 /* Check if the remaining data fits into current packet. */ 1394 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1395 if (copy < length) 1396 copy = maxfraglen - skb->len; 1397 1398 if (copy <= 0) { 1399 char *data; 1400 unsigned int datalen; 1401 unsigned int fraglen; 1402 unsigned int fraggap; 1403 unsigned int alloclen; 1404 alloc_new_skb: 1405 /* There's no room in the current skb */ 1406 if (skb) 1407 fraggap = skb->len - maxfraglen; 1408 else 1409 fraggap = 0; 1410 /* update mtu and maxfraglen if necessary */ 1411 if (!skb || !skb_prev) 1412 ip6_append_data_mtu(&mtu, &maxfraglen, 1413 fragheaderlen, skb, rt, 1414 orig_mtu); 1415 1416 skb_prev = skb; 1417 1418 /* 1419 * If remaining data exceeds the mtu, 1420 * we know we need more fragment(s). 1421 */ 1422 datalen = length + fraggap; 1423 1424 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1425 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1426 if ((flags & MSG_MORE) && 1427 !(rt->dst.dev->features&NETIF_F_SG)) 1428 alloclen = mtu; 1429 else 1430 alloclen = datalen + fragheaderlen; 1431 1432 alloclen += dst_exthdrlen; 1433 1434 if (datalen != length + fraggap) { 1435 /* 1436 * this is not the last fragment, the trailer 1437 * space is regarded as data space. 1438 */ 1439 datalen += rt->dst.trailer_len; 1440 } 1441 1442 alloclen += rt->dst.trailer_len; 1443 fraglen = datalen + fragheaderlen; 1444 1445 /* 1446 * We just reserve space for fragment header. 1447 * Note: this may be overallocation if the message 1448 * (without MSG_MORE) fits into the MTU. 1449 */ 1450 alloclen += sizeof(struct frag_hdr); 1451 1452 if (transhdrlen) { 1453 skb = sock_alloc_send_skb(sk, 1454 alloclen + hh_len, 1455 (flags & MSG_DONTWAIT), &err); 1456 } else { 1457 skb = NULL; 1458 if (atomic_read(&sk->sk_wmem_alloc) <= 1459 2 * sk->sk_sndbuf) 1460 skb = sock_wmalloc(sk, 1461 alloclen + hh_len, 1, 1462 sk->sk_allocation); 1463 if (unlikely(!skb)) 1464 err = -ENOBUFS; 1465 } 1466 if (!skb) 1467 goto error; 1468 /* 1469 * Fill in the control structures 1470 */ 1471 skb->protocol = htons(ETH_P_IPV6); 1472 skb->ip_summed = csummode; 1473 skb->csum = 0; 1474 /* reserve for fragmentation and ipsec header */ 1475 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1476 dst_exthdrlen); 1477 1478 /* Only the initial fragment is time stamped */ 1479 skb_shinfo(skb)->tx_flags = tx_flags; 1480 tx_flags = 0; 1481 skb_shinfo(skb)->tskey = tskey; 1482 tskey = 0; 1483 1484 /* 1485 * Find where to start putting bytes 1486 */ 1487 data = skb_put(skb, fraglen); 1488 skb_set_network_header(skb, exthdrlen); 1489 data += fragheaderlen; 1490 skb->transport_header = (skb->network_header + 1491 fragheaderlen); 1492 if (fraggap) { 1493 skb->csum = skb_copy_and_csum_bits( 1494 skb_prev, maxfraglen, 1495 data + transhdrlen, fraggap, 0); 1496 skb_prev->csum = csum_sub(skb_prev->csum, 1497 skb->csum); 1498 data += fraggap; 1499 pskb_trim_unique(skb_prev, maxfraglen); 1500 } 1501 copy = datalen - transhdrlen - fraggap; 1502 1503 if (copy < 0) { 1504 err = -EINVAL; 1505 kfree_skb(skb); 1506 goto error; 1507 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1508 err = -EFAULT; 1509 kfree_skb(skb); 1510 goto error; 1511 } 1512 1513 offset += copy; 1514 length -= datalen - fraggap; 1515 transhdrlen = 0; 1516 exthdrlen = 0; 1517 dst_exthdrlen = 0; 1518 1519 /* 1520 * Put the packet on the pending queue 1521 */ 1522 __skb_queue_tail(queue, skb); 1523 continue; 1524 } 1525 1526 if (copy > length) 1527 copy = length; 1528 1529 if (!(rt->dst.dev->features&NETIF_F_SG)) { 1530 unsigned int off; 1531 1532 off = skb->len; 1533 if (getfrag(from, skb_put(skb, copy), 1534 offset, copy, off, skb) < 0) { 1535 __skb_trim(skb, off); 1536 err = -EFAULT; 1537 goto error; 1538 } 1539 } else { 1540 int i = skb_shinfo(skb)->nr_frags; 1541 1542 err = -ENOMEM; 1543 if (!sk_page_frag_refill(sk, pfrag)) 1544 goto error; 1545 1546 if (!skb_can_coalesce(skb, i, pfrag->page, 1547 pfrag->offset)) { 1548 err = -EMSGSIZE; 1549 if (i == MAX_SKB_FRAGS) 1550 goto error; 1551 1552 __skb_fill_page_desc(skb, i, pfrag->page, 1553 pfrag->offset, 0); 1554 skb_shinfo(skb)->nr_frags = ++i; 1555 get_page(pfrag->page); 1556 } 1557 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1558 if (getfrag(from, 1559 page_address(pfrag->page) + pfrag->offset, 1560 offset, copy, skb->len, skb) < 0) 1561 goto error_efault; 1562 1563 pfrag->offset += copy; 1564 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1565 skb->len += copy; 1566 skb->data_len += copy; 1567 skb->truesize += copy; 1568 atomic_add(copy, &sk->sk_wmem_alloc); 1569 } 1570 offset += copy; 1571 length -= copy; 1572 } 1573 1574 return 0; 1575 1576 error_efault: 1577 err = -EFAULT; 1578 error: 1579 cork->length -= length; 1580 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1581 return err; 1582 } 1583 1584 int ip6_append_data(struct sock *sk, 1585 int getfrag(void *from, char *to, int offset, int len, 1586 int odd, struct sk_buff *skb), 1587 void *from, int length, int transhdrlen, 1588 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1589 struct rt6_info *rt, unsigned int flags, 1590 const struct sockcm_cookie *sockc) 1591 { 1592 struct inet_sock *inet = inet_sk(sk); 1593 struct ipv6_pinfo *np = inet6_sk(sk); 1594 int exthdrlen; 1595 int err; 1596 1597 if (flags&MSG_PROBE) 1598 return 0; 1599 if (skb_queue_empty(&sk->sk_write_queue)) { 1600 /* 1601 * setup for corking 1602 */ 1603 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1604 ipc6, rt, fl6); 1605 if (err) 1606 return err; 1607 1608 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1609 length += exthdrlen; 1610 transhdrlen += exthdrlen; 1611 } else { 1612 fl6 = &inet->cork.fl.u.ip6; 1613 transhdrlen = 0; 1614 } 1615 1616 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1617 &np->cork, sk_page_frag(sk), getfrag, 1618 from, length, transhdrlen, flags, ipc6, sockc); 1619 } 1620 EXPORT_SYMBOL_GPL(ip6_append_data); 1621 1622 static void ip6_cork_release(struct inet_cork_full *cork, 1623 struct inet6_cork *v6_cork) 1624 { 1625 if (v6_cork->opt) { 1626 kfree(v6_cork->opt->dst0opt); 1627 kfree(v6_cork->opt->dst1opt); 1628 kfree(v6_cork->opt->hopopt); 1629 kfree(v6_cork->opt->srcrt); 1630 kfree(v6_cork->opt); 1631 v6_cork->opt = NULL; 1632 } 1633 1634 if (cork->base.dst) { 1635 dst_release(cork->base.dst); 1636 cork->base.dst = NULL; 1637 cork->base.flags &= ~IPCORK_ALLFRAG; 1638 } 1639 memset(&cork->fl, 0, sizeof(cork->fl)); 1640 } 1641 1642 struct sk_buff *__ip6_make_skb(struct sock *sk, 1643 struct sk_buff_head *queue, 1644 struct inet_cork_full *cork, 1645 struct inet6_cork *v6_cork) 1646 { 1647 struct sk_buff *skb, *tmp_skb; 1648 struct sk_buff **tail_skb; 1649 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1650 struct ipv6_pinfo *np = inet6_sk(sk); 1651 struct net *net = sock_net(sk); 1652 struct ipv6hdr *hdr; 1653 struct ipv6_txoptions *opt = v6_cork->opt; 1654 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1655 struct flowi6 *fl6 = &cork->fl.u.ip6; 1656 unsigned char proto = fl6->flowi6_proto; 1657 1658 skb = __skb_dequeue(queue); 1659 if (!skb) 1660 goto out; 1661 tail_skb = &(skb_shinfo(skb)->frag_list); 1662 1663 /* move skb->data to ip header from ext header */ 1664 if (skb->data < skb_network_header(skb)) 1665 __skb_pull(skb, skb_network_offset(skb)); 1666 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1667 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1668 *tail_skb = tmp_skb; 1669 tail_skb = &(tmp_skb->next); 1670 skb->len += tmp_skb->len; 1671 skb->data_len += tmp_skb->len; 1672 skb->truesize += tmp_skb->truesize; 1673 tmp_skb->destructor = NULL; 1674 tmp_skb->sk = NULL; 1675 } 1676 1677 /* Allow local fragmentation. */ 1678 skb->ignore_df = ip6_sk_ignore_df(sk); 1679 1680 *final_dst = fl6->daddr; 1681 __skb_pull(skb, skb_network_header_len(skb)); 1682 if (opt && opt->opt_flen) 1683 ipv6_push_frag_opts(skb, opt, &proto); 1684 if (opt && opt->opt_nflen) 1685 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1686 1687 skb_push(skb, sizeof(struct ipv6hdr)); 1688 skb_reset_network_header(skb); 1689 hdr = ipv6_hdr(skb); 1690 1691 ip6_flow_hdr(hdr, v6_cork->tclass, 1692 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1693 np->autoflowlabel, fl6)); 1694 hdr->hop_limit = v6_cork->hop_limit; 1695 hdr->nexthdr = proto; 1696 hdr->saddr = fl6->saddr; 1697 hdr->daddr = *final_dst; 1698 1699 skb->priority = sk->sk_priority; 1700 skb->mark = sk->sk_mark; 1701 1702 skb_dst_set(skb, dst_clone(&rt->dst)); 1703 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1704 if (proto == IPPROTO_ICMPV6) { 1705 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1706 1707 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1708 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1709 } 1710 1711 ip6_cork_release(cork, v6_cork); 1712 out: 1713 return skb; 1714 } 1715 1716 int ip6_send_skb(struct sk_buff *skb) 1717 { 1718 struct net *net = sock_net(skb->sk); 1719 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1720 int err; 1721 1722 err = ip6_local_out(net, skb->sk, skb); 1723 if (err) { 1724 if (err > 0) 1725 err = net_xmit_errno(err); 1726 if (err) 1727 IP6_INC_STATS(net, rt->rt6i_idev, 1728 IPSTATS_MIB_OUTDISCARDS); 1729 } 1730 1731 return err; 1732 } 1733 1734 int ip6_push_pending_frames(struct sock *sk) 1735 { 1736 struct sk_buff *skb; 1737 1738 skb = ip6_finish_skb(sk); 1739 if (!skb) 1740 return 0; 1741 1742 return ip6_send_skb(skb); 1743 } 1744 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1745 1746 static void __ip6_flush_pending_frames(struct sock *sk, 1747 struct sk_buff_head *queue, 1748 struct inet_cork_full *cork, 1749 struct inet6_cork *v6_cork) 1750 { 1751 struct sk_buff *skb; 1752 1753 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1754 if (skb_dst(skb)) 1755 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1756 IPSTATS_MIB_OUTDISCARDS); 1757 kfree_skb(skb); 1758 } 1759 1760 ip6_cork_release(cork, v6_cork); 1761 } 1762 1763 void ip6_flush_pending_frames(struct sock *sk) 1764 { 1765 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1766 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1767 } 1768 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1769 1770 struct sk_buff *ip6_make_skb(struct sock *sk, 1771 int getfrag(void *from, char *to, int offset, 1772 int len, int odd, struct sk_buff *skb), 1773 void *from, int length, int transhdrlen, 1774 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1775 struct rt6_info *rt, unsigned int flags, 1776 const struct sockcm_cookie *sockc) 1777 { 1778 struct inet_cork_full cork; 1779 struct inet6_cork v6_cork; 1780 struct sk_buff_head queue; 1781 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1782 int err; 1783 1784 if (flags & MSG_PROBE) 1785 return NULL; 1786 1787 __skb_queue_head_init(&queue); 1788 1789 cork.base.flags = 0; 1790 cork.base.addr = 0; 1791 cork.base.opt = NULL; 1792 v6_cork.opt = NULL; 1793 err = ip6_setup_cork(sk, &cork, &v6_cork, ipc6, rt, fl6); 1794 if (err) 1795 return ERR_PTR(err); 1796 1797 if (ipc6->dontfrag < 0) 1798 ipc6->dontfrag = inet6_sk(sk)->dontfrag; 1799 1800 err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork, 1801 ¤t->task_frag, getfrag, from, 1802 length + exthdrlen, transhdrlen + exthdrlen, 1803 flags, ipc6, sockc); 1804 if (err) { 1805 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork); 1806 return ERR_PTR(err); 1807 } 1808 1809 return __ip6_make_skb(sk, &queue, &cork, &v6_cork); 1810 } 1811