1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IPv6 output functions 4 * Linux INET6 implementation 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * 9 * Based on linux/net/ipv4/ip_output.c 10 * 11 * Changes: 12 * A.N.Kuznetsov : airthmetics in fragmentation. 13 * extension headers are implemented. 14 * route changes now work. 15 * ip6_forward does not confuse sniffers. 16 * etc. 17 * 18 * H. von Brand : Added missing #include <linux/string.h> 19 * Imran Patel : frag id should be in NBO 20 * Kazunori MIYAZAWA @USAGI 21 * : add ip6_append_data and related functions 22 * for datagram xmit 23 */ 24 25 #include <linux/errno.h> 26 #include <linux/kernel.h> 27 #include <linux/string.h> 28 #include <linux/socket.h> 29 #include <linux/net.h> 30 #include <linux/netdevice.h> 31 #include <linux/if_arp.h> 32 #include <linux/in6.h> 33 #include <linux/tcp.h> 34 #include <linux/route.h> 35 #include <linux/module.h> 36 #include <linux/slab.h> 37 38 #include <linux/bpf-cgroup.h> 39 #include <linux/netfilter.h> 40 #include <linux/netfilter_ipv6.h> 41 42 #include <net/sock.h> 43 #include <net/snmp.h> 44 45 #include <net/gso.h> 46 #include <net/ipv6.h> 47 #include <net/ndisc.h> 48 #include <net/protocol.h> 49 #include <net/ip6_route.h> 50 #include <net/addrconf.h> 51 #include <net/rawv6.h> 52 #include <net/icmp.h> 53 #include <net/xfrm.h> 54 #include <net/checksum.h> 55 #include <linux/mroute6.h> 56 #include <net/l3mdev.h> 57 #include <net/lwtunnel.h> 58 #include <net/ip_tunnels.h> 59 60 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) 61 { 62 struct dst_entry *dst = skb_dst(skb); 63 struct net_device *dev = dst->dev; 64 struct inet6_dev *idev = ip6_dst_idev(dst); 65 unsigned int hh_len = LL_RESERVED_SPACE(dev); 66 const struct in6_addr *daddr, *nexthop; 67 struct ipv6hdr *hdr; 68 struct neighbour *neigh; 69 int ret; 70 71 /* Be paranoid, rather than too clever. */ 72 if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) { 73 /* Make sure idev stays alive */ 74 rcu_read_lock(); 75 skb = skb_expand_head(skb, hh_len); 76 if (!skb) { 77 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 78 rcu_read_unlock(); 79 return -ENOMEM; 80 } 81 rcu_read_unlock(); 82 } 83 84 hdr = ipv6_hdr(skb); 85 daddr = &hdr->daddr; 86 if (ipv6_addr_is_multicast(daddr)) { 87 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) && 88 ((mroute6_is_socket(net, skb) && 89 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 90 ipv6_chk_mcast_addr(dev, daddr, &hdr->saddr))) { 91 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 92 93 /* Do not check for IFF_ALLMULTI; multicast routing 94 is not supported in any case. 95 */ 96 if (newskb) 97 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 98 net, sk, newskb, NULL, newskb->dev, 99 dev_loopback_xmit); 100 101 if (hdr->hop_limit == 0) { 102 IP6_INC_STATS(net, idev, 103 IPSTATS_MIB_OUTDISCARDS); 104 kfree_skb(skb); 105 return 0; 106 } 107 } 108 109 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len); 110 if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL && 111 !(dev->flags & IFF_LOOPBACK)) { 112 kfree_skb(skb); 113 return 0; 114 } 115 } 116 117 if (lwtunnel_xmit_redirect(dst->lwtstate)) { 118 int res = lwtunnel_xmit(skb); 119 120 if (res != LWTUNNEL_XMIT_CONTINUE) 121 return res; 122 } 123 124 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len); 125 126 rcu_read_lock(); 127 nexthop = rt6_nexthop(dst_rt6_info(dst), daddr); 128 neigh = __ipv6_neigh_lookup_noref(dev, nexthop); 129 130 if (IS_ERR_OR_NULL(neigh)) { 131 if (unlikely(!neigh)) 132 neigh = __neigh_create(&nd_tbl, nexthop, dev, false); 133 if (IS_ERR(neigh)) { 134 rcu_read_unlock(); 135 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES); 136 kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL); 137 return -EINVAL; 138 } 139 } 140 sock_confirm_neigh(skb, neigh); 141 ret = neigh_output(neigh, skb, false); 142 rcu_read_unlock(); 143 return ret; 144 } 145 146 static int 147 ip6_finish_output_gso_slowpath_drop(struct net *net, struct sock *sk, 148 struct sk_buff *skb, unsigned int mtu) 149 { 150 struct sk_buff *segs, *nskb; 151 netdev_features_t features; 152 int ret = 0; 153 154 /* Please see corresponding comment in ip_finish_output_gso 155 * describing the cases where GSO segment length exceeds the 156 * egress MTU. 157 */ 158 features = netif_skb_features(skb); 159 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); 160 if (IS_ERR_OR_NULL(segs)) { 161 kfree_skb(skb); 162 return -ENOMEM; 163 } 164 165 consume_skb(skb); 166 167 skb_list_walk_safe(segs, segs, nskb) { 168 int err; 169 170 skb_mark_not_on_list(segs); 171 /* Last GSO segment can be smaller than gso_size (and MTU). 172 * Adding a fragment header would produce an "atomic fragment", 173 * which is considered harmful (RFC-8021). Avoid that. 174 */ 175 err = segs->len > mtu ? 176 ip6_fragment(net, sk, segs, ip6_finish_output2) : 177 ip6_finish_output2(net, sk, segs); 178 if (err && ret == 0) 179 ret = err; 180 } 181 182 return ret; 183 } 184 185 static int ip6_finish_output_gso(struct net *net, struct sock *sk, 186 struct sk_buff *skb, unsigned int mtu) 187 { 188 if (!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) && 189 !skb_gso_validate_network_len(skb, mtu)) 190 return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu); 191 192 return ip6_finish_output2(net, sk, skb); 193 } 194 195 static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) 196 { 197 unsigned int mtu; 198 199 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 200 /* Policy lookup after SNAT yielded a new policy */ 201 if (skb_dst(skb)->xfrm) { 202 IP6CB(skb)->flags |= IP6SKB_REROUTED; 203 return dst_output(net, sk, skb); 204 } 205 #endif 206 207 mtu = ip6_skb_dst_mtu(skb); 208 if (skb_is_gso(skb)) 209 return ip6_finish_output_gso(net, sk, skb, mtu); 210 211 if (skb->len > mtu || 212 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) 213 return ip6_fragment(net, sk, skb, ip6_finish_output2); 214 215 return ip6_finish_output2(net, sk, skb); 216 } 217 218 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) 219 { 220 int ret; 221 222 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); 223 switch (ret) { 224 case NET_XMIT_SUCCESS: 225 case NET_XMIT_CN: 226 return __ip6_finish_output(net, sk, skb) ? : ret; 227 default: 228 kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS); 229 return ret; 230 } 231 } 232 233 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 234 { 235 struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev; 236 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 237 238 skb->protocol = htons(ETH_P_IPV6); 239 skb->dev = dev; 240 241 if (unlikely(!idev || READ_ONCE(idev->cnf.disable_ipv6))) { 242 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 243 kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED); 244 return 0; 245 } 246 247 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 248 net, sk, skb, indev, dev, 249 ip6_finish_output, 250 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 251 } 252 EXPORT_SYMBOL(ip6_output); 253 254 bool ip6_autoflowlabel(struct net *net, const struct sock *sk) 255 { 256 if (!inet6_test_bit(AUTOFLOWLABEL_SET, sk)) 257 return ip6_default_np_autolabel(net); 258 return inet6_test_bit(AUTOFLOWLABEL, sk); 259 } 260 261 /* 262 * xmit an sk_buff (used by TCP, SCTP and DCCP) 263 * Note : socket lock is not held for SYNACK packets, but might be modified 264 * by calls to skb_set_owner_w() and ipv6_local_error(), 265 * which are using proper atomic operations or spinlocks. 266 */ 267 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 268 __u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority) 269 { 270 struct net *net = sock_net(sk); 271 const struct ipv6_pinfo *np = inet6_sk(sk); 272 struct in6_addr *first_hop = &fl6->daddr; 273 struct dst_entry *dst = skb_dst(skb); 274 struct net_device *dev = dst->dev; 275 struct inet6_dev *idev = ip6_dst_idev(dst); 276 struct hop_jumbo_hdr *hop_jumbo; 277 int hoplen = sizeof(*hop_jumbo); 278 unsigned int head_room; 279 struct ipv6hdr *hdr; 280 u8 proto = fl6->flowi6_proto; 281 int seg_len = skb->len; 282 int hlimit = -1; 283 u32 mtu; 284 285 head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev); 286 if (opt) 287 head_room += opt->opt_nflen + opt->opt_flen; 288 289 if (unlikely(head_room > skb_headroom(skb))) { 290 /* Make sure idev stays alive */ 291 rcu_read_lock(); 292 skb = skb_expand_head(skb, head_room); 293 if (!skb) { 294 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 295 rcu_read_unlock(); 296 return -ENOBUFS; 297 } 298 rcu_read_unlock(); 299 } 300 301 if (opt) { 302 seg_len += opt->opt_nflen + opt->opt_flen; 303 304 if (opt->opt_flen) 305 ipv6_push_frag_opts(skb, opt, &proto); 306 307 if (opt->opt_nflen) 308 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop, 309 &fl6->saddr); 310 } 311 312 if (unlikely(seg_len > IPV6_MAXPLEN)) { 313 hop_jumbo = skb_push(skb, hoplen); 314 315 hop_jumbo->nexthdr = proto; 316 hop_jumbo->hdrlen = 0; 317 hop_jumbo->tlv_type = IPV6_TLV_JUMBO; 318 hop_jumbo->tlv_len = 4; 319 hop_jumbo->jumbo_payload_len = htonl(seg_len + hoplen); 320 321 proto = IPPROTO_HOPOPTS; 322 seg_len = 0; 323 IP6CB(skb)->flags |= IP6SKB_FAKEJUMBO; 324 } 325 326 skb_push(skb, sizeof(struct ipv6hdr)); 327 skb_reset_network_header(skb); 328 hdr = ipv6_hdr(skb); 329 330 /* 331 * Fill in the IPv6 header 332 */ 333 if (np) 334 hlimit = READ_ONCE(np->hop_limit); 335 if (hlimit < 0) 336 hlimit = ip6_dst_hoplimit(dst); 337 338 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 339 ip6_autoflowlabel(net, sk), fl6)); 340 341 hdr->payload_len = htons(seg_len); 342 hdr->nexthdr = proto; 343 hdr->hop_limit = hlimit; 344 345 hdr->saddr = fl6->saddr; 346 hdr->daddr = *first_hop; 347 348 skb->protocol = htons(ETH_P_IPV6); 349 skb->priority = priority; 350 skb->mark = mark; 351 352 mtu = dst_mtu(dst); 353 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 354 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS); 355 356 /* if egress device is enslaved to an L3 master device pass the 357 * skb to its handler for processing 358 */ 359 skb = l3mdev_ip6_out((struct sock *)sk, skb); 360 if (unlikely(!skb)) 361 return 0; 362 363 /* hooks should never assume socket lock is held. 364 * we promote our socket to non const 365 */ 366 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 367 net, (struct sock *)sk, skb, NULL, dev, 368 dst_output); 369 } 370 371 skb->dev = dev; 372 /* ipv6_local_error() does not require socket lock, 373 * we promote our socket to non const 374 */ 375 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu); 376 377 IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS); 378 kfree_skb(skb); 379 return -EMSGSIZE; 380 } 381 EXPORT_SYMBOL(ip6_xmit); 382 383 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 384 { 385 struct ip6_ra_chain *ra; 386 struct sock *last = NULL; 387 388 read_lock(&ip6_ra_lock); 389 for (ra = ip6_ra_chain; ra; ra = ra->next) { 390 struct sock *sk = ra->sk; 391 if (sk && ra->sel == sel && 392 (!sk->sk_bound_dev_if || 393 sk->sk_bound_dev_if == skb->dev->ifindex)) { 394 395 if (inet6_test_bit(RTALERT_ISOLATE, sk) && 396 !net_eq(sock_net(sk), dev_net(skb->dev))) { 397 continue; 398 } 399 if (last) { 400 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 401 if (skb2) 402 rawv6_rcv(last, skb2); 403 } 404 last = sk; 405 } 406 } 407 408 if (last) { 409 rawv6_rcv(last, skb); 410 read_unlock(&ip6_ra_lock); 411 return 1; 412 } 413 read_unlock(&ip6_ra_lock); 414 return 0; 415 } 416 417 static int ip6_forward_proxy_check(struct sk_buff *skb) 418 { 419 struct ipv6hdr *hdr = ipv6_hdr(skb); 420 u8 nexthdr = hdr->nexthdr; 421 __be16 frag_off; 422 int offset; 423 424 if (ipv6_ext_hdr(nexthdr)) { 425 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 426 if (offset < 0) 427 return 0; 428 } else 429 offset = sizeof(struct ipv6hdr); 430 431 if (nexthdr == IPPROTO_ICMPV6) { 432 struct icmp6hdr *icmp6; 433 434 if (!pskb_may_pull(skb, (skb_network_header(skb) + 435 offset + 1 - skb->data))) 436 return 0; 437 438 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 439 440 switch (icmp6->icmp6_type) { 441 case NDISC_ROUTER_SOLICITATION: 442 case NDISC_ROUTER_ADVERTISEMENT: 443 case NDISC_NEIGHBOUR_SOLICITATION: 444 case NDISC_NEIGHBOUR_ADVERTISEMENT: 445 case NDISC_REDIRECT: 446 /* For reaction involving unicast neighbor discovery 447 * message destined to the proxied address, pass it to 448 * input function. 449 */ 450 return 1; 451 default: 452 break; 453 } 454 } 455 456 /* 457 * The proxying router can't forward traffic sent to a link-local 458 * address, so signal the sender and discard the packet. This 459 * behavior is clarified by the MIPv6 specification. 460 */ 461 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 462 dst_link_failure(skb); 463 return -1; 464 } 465 466 return 0; 467 } 468 469 static inline int ip6_forward_finish(struct net *net, struct sock *sk, 470 struct sk_buff *skb) 471 { 472 #ifdef CONFIG_NET_SWITCHDEV 473 if (skb->offload_l3_fwd_mark) { 474 consume_skb(skb); 475 return 0; 476 } 477 #endif 478 479 skb_clear_tstamp(skb); 480 return dst_output(net, sk, skb); 481 } 482 483 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 484 { 485 if (skb->len <= mtu) 486 return false; 487 488 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 489 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 490 return true; 491 492 if (skb->ignore_df) 493 return false; 494 495 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu)) 496 return false; 497 498 return true; 499 } 500 501 int ip6_forward(struct sk_buff *skb) 502 { 503 struct dst_entry *dst = skb_dst(skb); 504 struct ipv6hdr *hdr = ipv6_hdr(skb); 505 struct inet6_skb_parm *opt = IP6CB(skb); 506 struct net *net = dev_net(dst->dev); 507 struct inet6_dev *idev; 508 SKB_DR(reason); 509 u32 mtu; 510 511 idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif)); 512 if (READ_ONCE(net->ipv6.devconf_all->forwarding) == 0) 513 goto error; 514 515 if (skb->pkt_type != PACKET_HOST) 516 goto drop; 517 518 if (unlikely(skb->sk)) 519 goto drop; 520 521 if (skb_warn_if_lro(skb)) 522 goto drop; 523 524 if (!READ_ONCE(net->ipv6.devconf_all->disable_policy) && 525 (!idev || !READ_ONCE(idev->cnf.disable_policy)) && 526 !xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 527 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 528 goto drop; 529 } 530 531 skb_forward_csum(skb); 532 533 /* 534 * We DO NOT make any processing on 535 * RA packets, pushing them to user level AS IS 536 * without ane WARRANTY that application will be able 537 * to interpret them. The reason is that we 538 * cannot make anything clever here. 539 * 540 * We are not end-node, so that if packet contains 541 * AH/ESP, we cannot make anything. 542 * Defragmentation also would be mistake, RA packets 543 * cannot be fragmented, because there is no warranty 544 * that different fragments will go along one path. --ANK 545 */ 546 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 547 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 548 return 0; 549 } 550 551 /* 552 * check and decrement ttl 553 */ 554 if (hdr->hop_limit <= 1) { 555 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 556 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 557 558 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 559 return -ETIMEDOUT; 560 } 561 562 /* XXX: idev->cnf.proxy_ndp? */ 563 if (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) && 564 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 565 int proxied = ip6_forward_proxy_check(skb); 566 if (proxied > 0) { 567 /* It's tempting to decrease the hop limit 568 * here by 1, as we do at the end of the 569 * function too. 570 * 571 * But that would be incorrect, as proxying is 572 * not forwarding. The ip6_input function 573 * will handle this packet locally, and it 574 * depends on the hop limit being unchanged. 575 * 576 * One example is the NDP hop limit, that 577 * always has to stay 255, but other would be 578 * similar checks around RA packets, where the 579 * user can even change the desired limit. 580 */ 581 return ip6_input(skb); 582 } else if (proxied < 0) { 583 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 584 goto drop; 585 } 586 } 587 588 if (!xfrm6_route_forward(skb)) { 589 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 590 SKB_DR_SET(reason, XFRM_POLICY); 591 goto drop; 592 } 593 dst = skb_dst(skb); 594 595 /* IPv6 specs say nothing about it, but it is clear that we cannot 596 send redirects to source routed frames. 597 We don't send redirects to frames decapsulated from IPsec. 598 */ 599 if (IP6CB(skb)->iif == dst->dev->ifindex && 600 opt->srcrt == 0 && !skb_sec_path(skb)) { 601 struct in6_addr *target = NULL; 602 struct inet_peer *peer; 603 struct rt6_info *rt; 604 605 /* 606 * incoming and outgoing devices are the same 607 * send a redirect. 608 */ 609 610 rt = dst_rt6_info(dst); 611 if (rt->rt6i_flags & RTF_GATEWAY) 612 target = &rt->rt6i_gateway; 613 else 614 target = &hdr->daddr; 615 616 rcu_read_lock(); 617 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr); 618 619 /* Limit redirects both by destination (here) 620 and by source (inside ndisc_send_redirect) 621 */ 622 if (inet_peer_xrlim_allow(peer, 1*HZ)) 623 ndisc_send_redirect(skb, target); 624 rcu_read_unlock(); 625 } else { 626 int addrtype = ipv6_addr_type(&hdr->saddr); 627 628 /* This check is security critical. */ 629 if (addrtype == IPV6_ADDR_ANY || 630 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 631 goto error; 632 if (addrtype & IPV6_ADDR_LINKLOCAL) { 633 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 634 ICMPV6_NOT_NEIGHBOUR, 0); 635 goto error; 636 } 637 } 638 639 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 640 641 mtu = ip6_dst_mtu_maybe_forward(dst, true); 642 if (mtu < IPV6_MIN_MTU) 643 mtu = IPV6_MIN_MTU; 644 645 if (ip6_pkt_too_big(skb, mtu)) { 646 /* Again, force OUTPUT device used as source address */ 647 skb->dev = dst->dev; 648 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 649 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS); 650 __IP6_INC_STATS(net, ip6_dst_idev(dst), 651 IPSTATS_MIB_FRAGFAILS); 652 kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG); 653 return -EMSGSIZE; 654 } 655 656 if (skb_cow(skb, dst->dev->hard_header_len)) { 657 __IP6_INC_STATS(net, ip6_dst_idev(dst), 658 IPSTATS_MIB_OUTDISCARDS); 659 goto drop; 660 } 661 662 hdr = ipv6_hdr(skb); 663 664 /* Mangling hops number delayed to point after skb COW */ 665 666 hdr->hop_limit--; 667 668 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, 669 net, NULL, skb, skb->dev, dst->dev, 670 ip6_forward_finish); 671 672 error: 673 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 674 SKB_DR_SET(reason, IP_INADDRERRORS); 675 drop: 676 kfree_skb_reason(skb, reason); 677 return -EINVAL; 678 } 679 680 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 681 { 682 to->pkt_type = from->pkt_type; 683 to->priority = from->priority; 684 to->protocol = from->protocol; 685 skb_dst_drop(to); 686 skb_dst_set(to, dst_clone(skb_dst(from))); 687 to->dev = from->dev; 688 to->mark = from->mark; 689 690 skb_copy_hash(to, from); 691 692 #ifdef CONFIG_NET_SCHED 693 to->tc_index = from->tc_index; 694 #endif 695 nf_copy(to, from); 696 skb_ext_copy(to, from); 697 skb_copy_secmark(to, from); 698 } 699 700 int ip6_fraglist_init(struct sk_buff *skb, unsigned int hlen, u8 *prevhdr, 701 u8 nexthdr, __be32 frag_id, 702 struct ip6_fraglist_iter *iter) 703 { 704 unsigned int first_len; 705 struct frag_hdr *fh; 706 707 /* BUILD HEADER */ 708 *prevhdr = NEXTHDR_FRAGMENT; 709 iter->tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 710 if (!iter->tmp_hdr) 711 return -ENOMEM; 712 713 iter->frag = skb_shinfo(skb)->frag_list; 714 skb_frag_list_init(skb); 715 716 iter->offset = 0; 717 iter->hlen = hlen; 718 iter->frag_id = frag_id; 719 iter->nexthdr = nexthdr; 720 721 __skb_pull(skb, hlen); 722 fh = __skb_push(skb, sizeof(struct frag_hdr)); 723 __skb_push(skb, hlen); 724 skb_reset_network_header(skb); 725 memcpy(skb_network_header(skb), iter->tmp_hdr, hlen); 726 727 fh->nexthdr = nexthdr; 728 fh->reserved = 0; 729 fh->frag_off = htons(IP6_MF); 730 fh->identification = frag_id; 731 732 first_len = skb_pagelen(skb); 733 skb->data_len = first_len - skb_headlen(skb); 734 skb->len = first_len; 735 ipv6_hdr(skb)->payload_len = htons(first_len - sizeof(struct ipv6hdr)); 736 737 return 0; 738 } 739 EXPORT_SYMBOL(ip6_fraglist_init); 740 741 void ip6_fraglist_prepare(struct sk_buff *skb, 742 struct ip6_fraglist_iter *iter) 743 { 744 struct sk_buff *frag = iter->frag; 745 unsigned int hlen = iter->hlen; 746 struct frag_hdr *fh; 747 748 frag->ip_summed = CHECKSUM_NONE; 749 skb_reset_transport_header(frag); 750 fh = __skb_push(frag, sizeof(struct frag_hdr)); 751 __skb_push(frag, hlen); 752 skb_reset_network_header(frag); 753 memcpy(skb_network_header(frag), iter->tmp_hdr, hlen); 754 iter->offset += skb->len - hlen - sizeof(struct frag_hdr); 755 fh->nexthdr = iter->nexthdr; 756 fh->reserved = 0; 757 fh->frag_off = htons(iter->offset); 758 if (frag->next) 759 fh->frag_off |= htons(IP6_MF); 760 fh->identification = iter->frag_id; 761 ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 762 ip6_copy_metadata(frag, skb); 763 } 764 EXPORT_SYMBOL(ip6_fraglist_prepare); 765 766 void ip6_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int mtu, 767 unsigned short needed_tailroom, int hdr_room, u8 *prevhdr, 768 u8 nexthdr, __be32 frag_id, struct ip6_frag_state *state) 769 { 770 state->prevhdr = prevhdr; 771 state->nexthdr = nexthdr; 772 state->frag_id = frag_id; 773 774 state->hlen = hlen; 775 state->mtu = mtu; 776 777 state->left = skb->len - hlen; /* Space per frame */ 778 state->ptr = hlen; /* Where to start from */ 779 780 state->hroom = hdr_room; 781 state->troom = needed_tailroom; 782 783 state->offset = 0; 784 } 785 EXPORT_SYMBOL(ip6_frag_init); 786 787 struct sk_buff *ip6_frag_next(struct sk_buff *skb, struct ip6_frag_state *state) 788 { 789 u8 *prevhdr = state->prevhdr, *fragnexthdr_offset; 790 struct sk_buff *frag; 791 struct frag_hdr *fh; 792 unsigned int len; 793 794 len = state->left; 795 /* IF: it doesn't fit, use 'mtu' - the data space left */ 796 if (len > state->mtu) 797 len = state->mtu; 798 /* IF: we are not sending up to and including the packet end 799 then align the next start on an eight byte boundary */ 800 if (len < state->left) 801 len &= ~7; 802 803 /* Allocate buffer */ 804 frag = alloc_skb(len + state->hlen + sizeof(struct frag_hdr) + 805 state->hroom + state->troom, GFP_ATOMIC); 806 if (!frag) 807 return ERR_PTR(-ENOMEM); 808 809 /* 810 * Set up data on packet 811 */ 812 813 ip6_copy_metadata(frag, skb); 814 skb_reserve(frag, state->hroom); 815 skb_put(frag, len + state->hlen + sizeof(struct frag_hdr)); 816 skb_reset_network_header(frag); 817 fh = (struct frag_hdr *)(skb_network_header(frag) + state->hlen); 818 frag->transport_header = (frag->network_header + state->hlen + 819 sizeof(struct frag_hdr)); 820 821 /* 822 * Charge the memory for the fragment to any owner 823 * it might possess 824 */ 825 if (skb->sk) 826 skb_set_owner_w(frag, skb->sk); 827 828 /* 829 * Copy the packet header into the new buffer. 830 */ 831 skb_copy_from_linear_data(skb, skb_network_header(frag), state->hlen); 832 833 fragnexthdr_offset = skb_network_header(frag); 834 fragnexthdr_offset += prevhdr - skb_network_header(skb); 835 *fragnexthdr_offset = NEXTHDR_FRAGMENT; 836 837 /* 838 * Build fragment header. 839 */ 840 fh->nexthdr = state->nexthdr; 841 fh->reserved = 0; 842 fh->identification = state->frag_id; 843 844 /* 845 * Copy a block of the IP datagram. 846 */ 847 BUG_ON(skb_copy_bits(skb, state->ptr, skb_transport_header(frag), 848 len)); 849 state->left -= len; 850 851 fh->frag_off = htons(state->offset); 852 if (state->left > 0) 853 fh->frag_off |= htons(IP6_MF); 854 ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 855 856 state->ptr += len; 857 state->offset += len; 858 859 return frag; 860 } 861 EXPORT_SYMBOL(ip6_frag_next); 862 863 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, 864 int (*output)(struct net *, struct sock *, struct sk_buff *)) 865 { 866 struct sk_buff *frag; 867 struct rt6_info *rt = dst_rt6_info(skb_dst(skb)); 868 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ? 869 inet6_sk(skb->sk) : NULL; 870 u8 tstamp_type = skb->tstamp_type; 871 struct ip6_frag_state state; 872 unsigned int mtu, hlen, nexthdr_offset; 873 ktime_t tstamp = skb->tstamp; 874 int hroom, err = 0; 875 __be32 frag_id; 876 u8 *prevhdr, nexthdr = 0; 877 878 err = ip6_find_1stfragopt(skb, &prevhdr); 879 if (err < 0) 880 goto fail; 881 hlen = err; 882 nexthdr = *prevhdr; 883 nexthdr_offset = prevhdr - skb_network_header(skb); 884 885 mtu = ip6_skb_dst_mtu(skb); 886 887 /* We must not fragment if the socket is set to force MTU discovery 888 * or if the skb it not generated by a local socket. 889 */ 890 if (unlikely(!skb->ignore_df && skb->len > mtu)) 891 goto fail_toobig; 892 893 if (IP6CB(skb)->frag_max_size) { 894 if (IP6CB(skb)->frag_max_size > mtu) 895 goto fail_toobig; 896 897 /* don't send fragments larger than what we received */ 898 mtu = IP6CB(skb)->frag_max_size; 899 if (mtu < IPV6_MIN_MTU) 900 mtu = IPV6_MIN_MTU; 901 } 902 903 if (np) { 904 u32 frag_size = READ_ONCE(np->frag_size); 905 906 if (frag_size && frag_size < mtu) 907 mtu = frag_size; 908 } 909 if (mtu < hlen + sizeof(struct frag_hdr) + 8) 910 goto fail_toobig; 911 mtu -= hlen + sizeof(struct frag_hdr); 912 913 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, 914 &ipv6_hdr(skb)->saddr); 915 916 if (skb->ip_summed == CHECKSUM_PARTIAL && 917 (err = skb_checksum_help(skb))) 918 goto fail; 919 920 prevhdr = skb_network_header(skb) + nexthdr_offset; 921 hroom = LL_RESERVED_SPACE(rt->dst.dev); 922 if (skb_has_frag_list(skb)) { 923 unsigned int first_len = skb_pagelen(skb); 924 struct ip6_fraglist_iter iter; 925 struct sk_buff *frag2; 926 927 if (first_len - hlen > mtu || 928 ((first_len - hlen) & 7) || 929 skb_cloned(skb) || 930 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr))) 931 goto slow_path; 932 933 skb_walk_frags(skb, frag) { 934 /* Correct geometry. */ 935 if (frag->len > mtu || 936 ((frag->len & 7) && frag->next) || 937 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr))) 938 goto slow_path_clean; 939 940 /* Partially cloned skb? */ 941 if (skb_shared(frag)) 942 goto slow_path_clean; 943 944 BUG_ON(frag->sk); 945 if (skb->sk) { 946 frag->sk = skb->sk; 947 frag->destructor = sock_wfree; 948 } 949 skb->truesize -= frag->truesize; 950 } 951 952 err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id, 953 &iter); 954 if (err < 0) 955 goto fail; 956 957 /* We prevent @rt from being freed. */ 958 rcu_read_lock(); 959 960 for (;;) { 961 /* Prepare header of the next frame, 962 * before previous one went down. */ 963 if (iter.frag) 964 ip6_fraglist_prepare(skb, &iter); 965 966 skb_set_delivery_time(skb, tstamp, tstamp_type); 967 err = output(net, sk, skb); 968 if (!err) 969 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 970 IPSTATS_MIB_FRAGCREATES); 971 972 if (err || !iter.frag) 973 break; 974 975 skb = ip6_fraglist_next(&iter); 976 } 977 978 kfree(iter.tmp_hdr); 979 980 if (err == 0) { 981 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 982 IPSTATS_MIB_FRAGOKS); 983 rcu_read_unlock(); 984 return 0; 985 } 986 987 kfree_skb_list(iter.frag); 988 989 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 990 IPSTATS_MIB_FRAGFAILS); 991 rcu_read_unlock(); 992 return err; 993 994 slow_path_clean: 995 skb_walk_frags(skb, frag2) { 996 if (frag2 == frag) 997 break; 998 frag2->sk = NULL; 999 frag2->destructor = NULL; 1000 skb->truesize += frag2->truesize; 1001 } 1002 } 1003 1004 slow_path: 1005 /* 1006 * Fragment the datagram. 1007 */ 1008 1009 ip6_frag_init(skb, hlen, mtu, rt->dst.dev->needed_tailroom, 1010 LL_RESERVED_SPACE(rt->dst.dev), prevhdr, nexthdr, frag_id, 1011 &state); 1012 1013 /* 1014 * Keep copying data until we run out. 1015 */ 1016 1017 while (state.left > 0) { 1018 frag = ip6_frag_next(skb, &state); 1019 if (IS_ERR(frag)) { 1020 err = PTR_ERR(frag); 1021 goto fail; 1022 } 1023 1024 /* 1025 * Put this fragment into the sending queue. 1026 */ 1027 skb_set_delivery_time(frag, tstamp, tstamp_type); 1028 err = output(net, sk, frag); 1029 if (err) 1030 goto fail; 1031 1032 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 1033 IPSTATS_MIB_FRAGCREATES); 1034 } 1035 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 1036 IPSTATS_MIB_FRAGOKS); 1037 consume_skb(skb); 1038 return err; 1039 1040 fail_toobig: 1041 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 1042 err = -EMSGSIZE; 1043 1044 fail: 1045 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 1046 IPSTATS_MIB_FRAGFAILS); 1047 kfree_skb(skb); 1048 return err; 1049 } 1050 1051 static inline int ip6_rt_check(const struct rt6key *rt_key, 1052 const struct in6_addr *fl_addr, 1053 const struct in6_addr *addr_cache) 1054 { 1055 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 1056 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache)); 1057 } 1058 1059 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 1060 struct dst_entry *dst, 1061 const struct flowi6 *fl6) 1062 { 1063 struct ipv6_pinfo *np = inet6_sk(sk); 1064 struct rt6_info *rt; 1065 1066 if (!dst) 1067 goto out; 1068 1069 if (dst->ops->family != AF_INET6) { 1070 dst_release(dst); 1071 return NULL; 1072 } 1073 1074 rt = dst_rt6_info(dst); 1075 /* Yes, checking route validity in not connected 1076 * case is not very simple. Take into account, 1077 * that we do not support routing by source, TOS, 1078 * and MSG_DONTROUTE --ANK (980726) 1079 * 1080 * 1. ip6_rt_check(): If route was host route, 1081 * check that cached destination is current. 1082 * If it is network route, we still may 1083 * check its validity using saved pointer 1084 * to the last used address: daddr_cache. 1085 * We do not want to save whole address now, 1086 * (because main consumer of this service 1087 * is tcp, which has not this problem), 1088 * so that the last trick works only on connected 1089 * sockets. 1090 * 2. oif also should be the same. 1091 */ 1092 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 1093 #ifdef CONFIG_IPV6_SUBTREES 1094 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 1095 #endif 1096 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) { 1097 dst_release(dst); 1098 dst = NULL; 1099 } 1100 1101 out: 1102 return dst; 1103 } 1104 1105 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 1106 struct dst_entry **dst, struct flowi6 *fl6) 1107 { 1108 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 1109 struct neighbour *n; 1110 struct rt6_info *rt; 1111 #endif 1112 int err; 1113 int flags = 0; 1114 1115 /* The correct way to handle this would be to do 1116 * ip6_route_get_saddr, and then ip6_route_output; however, 1117 * the route-specific preferred source forces the 1118 * ip6_route_output call _before_ ip6_route_get_saddr. 1119 * 1120 * In source specific routing (no src=any default route), 1121 * ip6_route_output will fail given src=any saddr, though, so 1122 * that's why we try it again later. 1123 */ 1124 if (ipv6_addr_any(&fl6->saddr)) { 1125 struct fib6_info *from; 1126 struct rt6_info *rt; 1127 1128 *dst = ip6_route_output(net, sk, fl6); 1129 rt = (*dst)->error ? NULL : dst_rt6_info(*dst); 1130 1131 rcu_read_lock(); 1132 from = rt ? rcu_dereference(rt->from) : NULL; 1133 err = ip6_route_get_saddr(net, from, &fl6->daddr, 1134 sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0, 1135 fl6->flowi6_l3mdev, 1136 &fl6->saddr); 1137 rcu_read_unlock(); 1138 1139 if (err) 1140 goto out_err_release; 1141 1142 /* If we had an erroneous initial result, pretend it 1143 * never existed and let the SA-enabled version take 1144 * over. 1145 */ 1146 if ((*dst)->error) { 1147 dst_release(*dst); 1148 *dst = NULL; 1149 } 1150 1151 if (fl6->flowi6_oif) 1152 flags |= RT6_LOOKUP_F_IFACE; 1153 } 1154 1155 if (!*dst) 1156 *dst = ip6_route_output_flags(net, sk, fl6, flags); 1157 1158 err = (*dst)->error; 1159 if (err) 1160 goto out_err_release; 1161 1162 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 1163 /* 1164 * Here if the dst entry we've looked up 1165 * has a neighbour entry that is in the INCOMPLETE 1166 * state and the src address from the flow is 1167 * marked as OPTIMISTIC, we release the found 1168 * dst entry and replace it instead with the 1169 * dst entry of the nexthop router 1170 */ 1171 rt = dst_rt6_info(*dst); 1172 rcu_read_lock(); 1173 n = __ipv6_neigh_lookup_noref(rt->dst.dev, 1174 rt6_nexthop(rt, &fl6->daddr)); 1175 err = n && !(READ_ONCE(n->nud_state) & NUD_VALID) ? -EINVAL : 0; 1176 rcu_read_unlock(); 1177 1178 if (err) { 1179 struct inet6_ifaddr *ifp; 1180 struct flowi6 fl_gw6; 1181 int redirect; 1182 1183 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 1184 (*dst)->dev, 1); 1185 1186 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 1187 if (ifp) 1188 in6_ifa_put(ifp); 1189 1190 if (redirect) { 1191 /* 1192 * We need to get the dst entry for the 1193 * default router instead 1194 */ 1195 dst_release(*dst); 1196 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 1197 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 1198 *dst = ip6_route_output(net, sk, &fl_gw6); 1199 err = (*dst)->error; 1200 if (err) 1201 goto out_err_release; 1202 } 1203 } 1204 #endif 1205 if (ipv6_addr_v4mapped(&fl6->saddr) && 1206 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) { 1207 err = -EAFNOSUPPORT; 1208 goto out_err_release; 1209 } 1210 1211 return 0; 1212 1213 out_err_release: 1214 dst_release(*dst); 1215 *dst = NULL; 1216 1217 if (err == -ENETUNREACH) 1218 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 1219 return err; 1220 } 1221 1222 /** 1223 * ip6_dst_lookup - perform route lookup on flow 1224 * @net: Network namespace to perform lookup in 1225 * @sk: socket which provides route info 1226 * @dst: pointer to dst_entry * for result 1227 * @fl6: flow to lookup 1228 * 1229 * This function performs a route lookup on the given flow. 1230 * 1231 * It returns zero on success, or a standard errno code on error. 1232 */ 1233 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst, 1234 struct flowi6 *fl6) 1235 { 1236 *dst = NULL; 1237 return ip6_dst_lookup_tail(net, sk, dst, fl6); 1238 } 1239 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 1240 1241 /** 1242 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 1243 * @net: Network namespace to perform lookup in 1244 * @sk: socket which provides route info 1245 * @fl6: flow to lookup 1246 * @final_dst: final destination address for ipsec lookup 1247 * 1248 * This function performs a route lookup on the given flow. 1249 * 1250 * It returns a valid dst pointer on success, or a pointer encoded 1251 * error code. 1252 */ 1253 struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6, 1254 const struct in6_addr *final_dst) 1255 { 1256 struct dst_entry *dst = NULL; 1257 int err; 1258 1259 err = ip6_dst_lookup_tail(net, sk, &dst, fl6); 1260 if (err) 1261 return ERR_PTR(err); 1262 if (final_dst) 1263 fl6->daddr = *final_dst; 1264 1265 return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0); 1266 } 1267 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1268 1269 /** 1270 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1271 * @sk: socket which provides the dst cache and route info 1272 * @fl6: flow to lookup 1273 * @final_dst: final destination address for ipsec lookup 1274 * @connected: whether @sk is connected or not 1275 * 1276 * This function performs a route lookup on the given flow with the 1277 * possibility of using the cached route in the socket if it is valid. 1278 * It will take the socket dst lock when operating on the dst cache. 1279 * As a result, this function can only be used in process context. 1280 * 1281 * In addition, for a connected socket, cache the dst in the socket 1282 * if the current cache is not valid. 1283 * 1284 * It returns a valid dst pointer on success, or a pointer encoded 1285 * error code. 1286 */ 1287 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1288 const struct in6_addr *final_dst, 1289 bool connected) 1290 { 1291 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1292 1293 dst = ip6_sk_dst_check(sk, dst, fl6); 1294 if (dst) 1295 return dst; 1296 1297 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst); 1298 if (connected && !IS_ERR(dst)) 1299 ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6); 1300 1301 return dst; 1302 } 1303 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1304 1305 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1306 gfp_t gfp) 1307 { 1308 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1309 } 1310 1311 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1312 gfp_t gfp) 1313 { 1314 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1315 } 1316 1317 static void ip6_append_data_mtu(unsigned int *mtu, 1318 int *maxfraglen, 1319 unsigned int fragheaderlen, 1320 struct sk_buff *skb, 1321 struct rt6_info *rt, 1322 unsigned int orig_mtu) 1323 { 1324 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1325 if (!skb) { 1326 /* first fragment, reserve header_len */ 1327 *mtu = orig_mtu - rt->dst.header_len; 1328 1329 } else { 1330 /* 1331 * this fragment is not first, the headers 1332 * space is regarded as data space. 1333 */ 1334 *mtu = orig_mtu; 1335 } 1336 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1337 + fragheaderlen - sizeof(struct frag_hdr); 1338 } 1339 } 1340 1341 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1342 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6, 1343 struct rt6_info *rt) 1344 { 1345 struct ipv6_pinfo *np = inet6_sk(sk); 1346 unsigned int mtu, frag_size; 1347 struct ipv6_txoptions *nopt, *opt = ipc6->opt; 1348 1349 /* callers pass dst together with a reference, set it first so 1350 * ip6_cork_release() can put it down even in case of an error. 1351 */ 1352 cork->base.dst = &rt->dst; 1353 1354 /* 1355 * setup for corking 1356 */ 1357 if (opt) { 1358 if (WARN_ON(v6_cork->opt)) 1359 return -EINVAL; 1360 1361 nopt = v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation); 1362 if (unlikely(!nopt)) 1363 return -ENOBUFS; 1364 1365 nopt->tot_len = sizeof(*opt); 1366 nopt->opt_flen = opt->opt_flen; 1367 nopt->opt_nflen = opt->opt_nflen; 1368 1369 nopt->dst0opt = ip6_opt_dup(opt->dst0opt, sk->sk_allocation); 1370 if (opt->dst0opt && !nopt->dst0opt) 1371 return -ENOBUFS; 1372 1373 nopt->dst1opt = ip6_opt_dup(opt->dst1opt, sk->sk_allocation); 1374 if (opt->dst1opt && !nopt->dst1opt) 1375 return -ENOBUFS; 1376 1377 nopt->hopopt = ip6_opt_dup(opt->hopopt, sk->sk_allocation); 1378 if (opt->hopopt && !nopt->hopopt) 1379 return -ENOBUFS; 1380 1381 nopt->srcrt = ip6_rthdr_dup(opt->srcrt, sk->sk_allocation); 1382 if (opt->srcrt && !nopt->srcrt) 1383 return -ENOBUFS; 1384 1385 /* need source address above miyazawa*/ 1386 } 1387 v6_cork->hop_limit = ipc6->hlimit; 1388 v6_cork->tclass = ipc6->tclass; 1389 if (rt->dst.flags & DST_XFRM_TUNNEL) 1390 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? 1391 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst); 1392 else 1393 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? 1394 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst)); 1395 1396 frag_size = READ_ONCE(np->frag_size); 1397 if (frag_size && frag_size < mtu) 1398 mtu = frag_size; 1399 1400 cork->base.fragsize = mtu; 1401 cork->base.gso_size = ipc6->gso_size; 1402 cork->base.tx_flags = 0; 1403 cork->base.mark = ipc6->sockc.mark; 1404 cork->base.priority = ipc6->sockc.priority; 1405 sock_tx_timestamp(sk, &ipc6->sockc, &cork->base.tx_flags); 1406 if (ipc6->sockc.tsflags & SOCKCM_FLAG_TS_OPT_ID) { 1407 cork->base.flags |= IPCORK_TS_OPT_ID; 1408 cork->base.ts_opt_id = ipc6->sockc.ts_opt_id; 1409 } 1410 cork->base.length = 0; 1411 cork->base.transmit_time = ipc6->sockc.transmit_time; 1412 1413 return 0; 1414 } 1415 1416 static int __ip6_append_data(struct sock *sk, 1417 struct sk_buff_head *queue, 1418 struct inet_cork_full *cork_full, 1419 struct inet6_cork *v6_cork, 1420 struct page_frag *pfrag, 1421 int getfrag(void *from, char *to, int offset, 1422 int len, int odd, struct sk_buff *skb), 1423 void *from, size_t length, int transhdrlen, 1424 unsigned int flags, struct ipcm6_cookie *ipc6) 1425 { 1426 struct sk_buff *skb, *skb_prev = NULL; 1427 struct inet_cork *cork = &cork_full->base; 1428 struct flowi6 *fl6 = &cork_full->fl.u.ip6; 1429 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; 1430 struct ubuf_info *uarg = NULL; 1431 int exthdrlen = 0; 1432 int dst_exthdrlen = 0; 1433 int hh_len; 1434 int copy; 1435 int err; 1436 int offset = 0; 1437 bool zc = false; 1438 u32 tskey = 0; 1439 struct rt6_info *rt = dst_rt6_info(cork->dst); 1440 bool paged, hold_tskey = false, extra_uref = false; 1441 struct ipv6_txoptions *opt = v6_cork->opt; 1442 int csummode = CHECKSUM_NONE; 1443 unsigned int maxnonfragsize, headersize; 1444 unsigned int wmem_alloc_delta = 0; 1445 1446 skb = skb_peek_tail(queue); 1447 if (!skb) { 1448 exthdrlen = opt ? opt->opt_flen : 0; 1449 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1450 } 1451 1452 paged = !!cork->gso_size; 1453 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize; 1454 orig_mtu = mtu; 1455 1456 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1457 1458 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1459 (opt ? opt->opt_nflen : 0); 1460 1461 headersize = sizeof(struct ipv6hdr) + 1462 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1463 rt->rt6i_nfheader_len; 1464 1465 if (mtu <= fragheaderlen || 1466 ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr)) 1467 goto emsgsize; 1468 1469 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1470 sizeof(struct frag_hdr); 1471 1472 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit 1473 * the first fragment 1474 */ 1475 if (headersize + transhdrlen > mtu) 1476 goto emsgsize; 1477 1478 if (cork->length + length > mtu - headersize && ipc6->dontfrag && 1479 (sk->sk_protocol == IPPROTO_UDP || 1480 sk->sk_protocol == IPPROTO_ICMPV6 || 1481 sk->sk_protocol == IPPROTO_RAW)) { 1482 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1483 sizeof(struct ipv6hdr)); 1484 goto emsgsize; 1485 } 1486 1487 if (ip6_sk_ignore_df(sk)) 1488 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1489 else 1490 maxnonfragsize = mtu; 1491 1492 if (cork->length + length > maxnonfragsize - headersize) { 1493 emsgsize: 1494 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); 1495 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); 1496 return -EMSGSIZE; 1497 } 1498 1499 /* CHECKSUM_PARTIAL only with no extension headers and when 1500 * we are not going to fragment 1501 */ 1502 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1503 headersize == sizeof(struct ipv6hdr) && 1504 length <= mtu - headersize && 1505 (!(flags & MSG_MORE) || cork->gso_size) && 1506 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM)) 1507 csummode = CHECKSUM_PARTIAL; 1508 1509 if ((flags & MSG_ZEROCOPY) && length) { 1510 struct msghdr *msg = from; 1511 1512 if (getfrag == ip_generic_getfrag && msg->msg_ubuf) { 1513 if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb)) 1514 return -EINVAL; 1515 1516 /* Leave uarg NULL if can't zerocopy, callers should 1517 * be able to handle it. 1518 */ 1519 if ((rt->dst.dev->features & NETIF_F_SG) && 1520 csummode == CHECKSUM_PARTIAL) { 1521 paged = true; 1522 zc = true; 1523 uarg = msg->msg_ubuf; 1524 } 1525 } else if (sock_flag(sk, SOCK_ZEROCOPY)) { 1526 uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); 1527 if (!uarg) 1528 return -ENOBUFS; 1529 extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ 1530 if (rt->dst.dev->features & NETIF_F_SG && 1531 csummode == CHECKSUM_PARTIAL) { 1532 paged = true; 1533 zc = true; 1534 } else { 1535 uarg_to_msgzc(uarg)->zerocopy = 0; 1536 skb_zcopy_set(skb, uarg, &extra_uref); 1537 } 1538 } 1539 } else if ((flags & MSG_SPLICE_PAGES) && length) { 1540 if (inet_test_bit(HDRINCL, sk)) 1541 return -EPERM; 1542 if (rt->dst.dev->features & NETIF_F_SG && 1543 getfrag == ip_generic_getfrag) 1544 /* We need an empty buffer to attach stuff to */ 1545 paged = true; 1546 else 1547 flags &= ~MSG_SPLICE_PAGES; 1548 } 1549 1550 if (cork->tx_flags & SKBTX_ANY_TSTAMP && 1551 READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) { 1552 if (cork->flags & IPCORK_TS_OPT_ID) { 1553 tskey = cork->ts_opt_id; 1554 } else { 1555 tskey = atomic_inc_return(&sk->sk_tskey) - 1; 1556 hold_tskey = true; 1557 } 1558 } 1559 1560 /* 1561 * Let's try using as much space as possible. 1562 * Use MTU if total length of the message fits into the MTU. 1563 * Otherwise, we need to reserve fragment header and 1564 * fragment alignment (= 8-15 octects, in total). 1565 * 1566 * Note that we may need to "move" the data from the tail 1567 * of the buffer to the new fragment when we split 1568 * the message. 1569 * 1570 * FIXME: It may be fragmented into multiple chunks 1571 * at once if non-fragmentable extension headers 1572 * are too large. 1573 * --yoshfuji 1574 */ 1575 1576 cork->length += length; 1577 if (!skb) 1578 goto alloc_new_skb; 1579 1580 while (length > 0) { 1581 /* Check if the remaining data fits into current packet. */ 1582 copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len; 1583 if (copy < length) 1584 copy = maxfraglen - skb->len; 1585 1586 if (copy <= 0) { 1587 char *data; 1588 unsigned int datalen; 1589 unsigned int fraglen; 1590 unsigned int fraggap; 1591 unsigned int alloclen, alloc_extra; 1592 unsigned int pagedlen; 1593 alloc_new_skb: 1594 /* There's no room in the current skb */ 1595 if (skb) 1596 fraggap = skb->len - maxfraglen; 1597 else 1598 fraggap = 0; 1599 /* update mtu and maxfraglen if necessary */ 1600 if (!skb || !skb_prev) 1601 ip6_append_data_mtu(&mtu, &maxfraglen, 1602 fragheaderlen, skb, rt, 1603 orig_mtu); 1604 1605 skb_prev = skb; 1606 1607 /* 1608 * If remaining data exceeds the mtu, 1609 * we know we need more fragment(s). 1610 */ 1611 datalen = length + fraggap; 1612 1613 if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen) 1614 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1615 fraglen = datalen + fragheaderlen; 1616 pagedlen = 0; 1617 1618 alloc_extra = hh_len; 1619 alloc_extra += dst_exthdrlen; 1620 alloc_extra += rt->dst.trailer_len; 1621 1622 /* We just reserve space for fragment header. 1623 * Note: this may be overallocation if the message 1624 * (without MSG_MORE) fits into the MTU. 1625 */ 1626 alloc_extra += sizeof(struct frag_hdr); 1627 1628 if ((flags & MSG_MORE) && 1629 !(rt->dst.dev->features&NETIF_F_SG)) 1630 alloclen = mtu; 1631 else if (!paged && 1632 (fraglen + alloc_extra < SKB_MAX_ALLOC || 1633 !(rt->dst.dev->features & NETIF_F_SG))) 1634 alloclen = fraglen; 1635 else { 1636 alloclen = fragheaderlen + transhdrlen; 1637 pagedlen = datalen - transhdrlen; 1638 } 1639 alloclen += alloc_extra; 1640 1641 if (datalen != length + fraggap) { 1642 /* 1643 * this is not the last fragment, the trailer 1644 * space is regarded as data space. 1645 */ 1646 datalen += rt->dst.trailer_len; 1647 } 1648 1649 fraglen = datalen + fragheaderlen; 1650 1651 copy = datalen - transhdrlen - fraggap - pagedlen; 1652 /* [!] NOTE: copy may be negative if pagedlen>0 1653 * because then the equation may reduces to -fraggap. 1654 */ 1655 if (copy < 0 && !(flags & MSG_SPLICE_PAGES)) { 1656 err = -EINVAL; 1657 goto error; 1658 } 1659 if (transhdrlen) { 1660 skb = sock_alloc_send_skb(sk, alloclen, 1661 (flags & MSG_DONTWAIT), &err); 1662 } else { 1663 skb = NULL; 1664 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 1665 2 * sk->sk_sndbuf) 1666 skb = alloc_skb(alloclen, 1667 sk->sk_allocation); 1668 if (unlikely(!skb)) 1669 err = -ENOBUFS; 1670 } 1671 if (!skb) 1672 goto error; 1673 /* 1674 * Fill in the control structures 1675 */ 1676 skb->protocol = htons(ETH_P_IPV6); 1677 skb->ip_summed = csummode; 1678 skb->csum = 0; 1679 /* reserve for fragmentation and ipsec header */ 1680 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1681 dst_exthdrlen); 1682 1683 /* 1684 * Find where to start putting bytes 1685 */ 1686 data = skb_put(skb, fraglen - pagedlen); 1687 skb_set_network_header(skb, exthdrlen); 1688 data += fragheaderlen; 1689 skb->transport_header = (skb->network_header + 1690 fragheaderlen); 1691 if (fraggap) { 1692 skb->csum = skb_copy_and_csum_bits( 1693 skb_prev, maxfraglen, 1694 data + transhdrlen, fraggap); 1695 skb_prev->csum = csum_sub(skb_prev->csum, 1696 skb->csum); 1697 data += fraggap; 1698 pskb_trim_unique(skb_prev, maxfraglen); 1699 } 1700 if (copy > 0 && 1701 INDIRECT_CALL_1(getfrag, ip_generic_getfrag, 1702 from, data + transhdrlen, offset, 1703 copy, fraggap, skb) < 0) { 1704 err = -EFAULT; 1705 kfree_skb(skb); 1706 goto error; 1707 } else if (flags & MSG_SPLICE_PAGES) { 1708 copy = 0; 1709 } 1710 1711 offset += copy; 1712 length -= copy + transhdrlen; 1713 transhdrlen = 0; 1714 exthdrlen = 0; 1715 dst_exthdrlen = 0; 1716 1717 /* Only the initial fragment is time stamped */ 1718 skb_shinfo(skb)->tx_flags = cork->tx_flags; 1719 cork->tx_flags = 0; 1720 skb_shinfo(skb)->tskey = tskey; 1721 tskey = 0; 1722 skb_zcopy_set(skb, uarg, &extra_uref); 1723 1724 if ((flags & MSG_CONFIRM) && !skb_prev) 1725 skb_set_dst_pending_confirm(skb, 1); 1726 1727 /* 1728 * Put the packet on the pending queue 1729 */ 1730 if (!skb->destructor) { 1731 skb->destructor = sock_wfree; 1732 skb->sk = sk; 1733 wmem_alloc_delta += skb->truesize; 1734 } 1735 __skb_queue_tail(queue, skb); 1736 continue; 1737 } 1738 1739 if (copy > length) 1740 copy = length; 1741 1742 if (!(rt->dst.dev->features&NETIF_F_SG) && 1743 skb_tailroom(skb) >= copy) { 1744 unsigned int off; 1745 1746 off = skb->len; 1747 if (INDIRECT_CALL_1(getfrag, ip_generic_getfrag, 1748 from, skb_put(skb, copy), 1749 offset, copy, off, skb) < 0) { 1750 __skb_trim(skb, off); 1751 err = -EFAULT; 1752 goto error; 1753 } 1754 } else if (flags & MSG_SPLICE_PAGES) { 1755 struct msghdr *msg = from; 1756 1757 err = -EIO; 1758 if (WARN_ON_ONCE(copy > msg->msg_iter.count)) 1759 goto error; 1760 1761 err = skb_splice_from_iter(skb, &msg->msg_iter, copy, 1762 sk->sk_allocation); 1763 if (err < 0) 1764 goto error; 1765 copy = err; 1766 wmem_alloc_delta += copy; 1767 } else if (!zc) { 1768 int i = skb_shinfo(skb)->nr_frags; 1769 1770 err = -ENOMEM; 1771 if (!sk_page_frag_refill(sk, pfrag)) 1772 goto error; 1773 1774 skb_zcopy_downgrade_managed(skb); 1775 if (!skb_can_coalesce(skb, i, pfrag->page, 1776 pfrag->offset)) { 1777 err = -EMSGSIZE; 1778 if (i == MAX_SKB_FRAGS) 1779 goto error; 1780 1781 __skb_fill_page_desc(skb, i, pfrag->page, 1782 pfrag->offset, 0); 1783 skb_shinfo(skb)->nr_frags = ++i; 1784 get_page(pfrag->page); 1785 } 1786 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1787 if (INDIRECT_CALL_1(getfrag, ip_generic_getfrag, 1788 from, 1789 page_address(pfrag->page) + pfrag->offset, 1790 offset, copy, skb->len, skb) < 0) 1791 goto error_efault; 1792 1793 pfrag->offset += copy; 1794 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1795 skb->len += copy; 1796 skb->data_len += copy; 1797 skb->truesize += copy; 1798 wmem_alloc_delta += copy; 1799 } else { 1800 err = skb_zerocopy_iter_dgram(skb, from, copy); 1801 if (err < 0) 1802 goto error; 1803 } 1804 offset += copy; 1805 length -= copy; 1806 } 1807 1808 if (wmem_alloc_delta) 1809 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1810 return 0; 1811 1812 error_efault: 1813 err = -EFAULT; 1814 error: 1815 net_zcopy_put_abort(uarg, extra_uref); 1816 cork->length -= length; 1817 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1818 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1819 if (hold_tskey) 1820 atomic_dec(&sk->sk_tskey); 1821 return err; 1822 } 1823 1824 int ip6_append_data(struct sock *sk, 1825 int getfrag(void *from, char *to, int offset, int len, 1826 int odd, struct sk_buff *skb), 1827 void *from, size_t length, int transhdrlen, 1828 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1829 struct rt6_info *rt, unsigned int flags) 1830 { 1831 struct inet_sock *inet = inet_sk(sk); 1832 struct ipv6_pinfo *np = inet6_sk(sk); 1833 int exthdrlen; 1834 int err; 1835 1836 if (flags&MSG_PROBE) 1837 return 0; 1838 if (skb_queue_empty(&sk->sk_write_queue)) { 1839 /* 1840 * setup for corking 1841 */ 1842 dst_hold(&rt->dst); 1843 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1844 ipc6, rt); 1845 if (err) 1846 return err; 1847 1848 inet->cork.fl.u.ip6 = *fl6; 1849 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1850 length += exthdrlen; 1851 transhdrlen += exthdrlen; 1852 } else { 1853 transhdrlen = 0; 1854 } 1855 1856 return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork, 1857 &np->cork, sk_page_frag(sk), getfrag, 1858 from, length, transhdrlen, flags, ipc6); 1859 } 1860 EXPORT_SYMBOL_GPL(ip6_append_data); 1861 1862 static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork) 1863 { 1864 struct dst_entry *dst = cork->base.dst; 1865 1866 cork->base.dst = NULL; 1867 skb_dst_set(skb, dst); 1868 } 1869 1870 static void ip6_cork_release(struct inet_cork_full *cork, 1871 struct inet6_cork *v6_cork) 1872 { 1873 if (v6_cork->opt) { 1874 struct ipv6_txoptions *opt = v6_cork->opt; 1875 1876 kfree(opt->dst0opt); 1877 kfree(opt->dst1opt); 1878 kfree(opt->hopopt); 1879 kfree(opt->srcrt); 1880 kfree(opt); 1881 v6_cork->opt = NULL; 1882 } 1883 1884 if (cork->base.dst) { 1885 dst_release(cork->base.dst); 1886 cork->base.dst = NULL; 1887 } 1888 } 1889 1890 struct sk_buff *__ip6_make_skb(struct sock *sk, 1891 struct sk_buff_head *queue, 1892 struct inet_cork_full *cork, 1893 struct inet6_cork *v6_cork) 1894 { 1895 struct sk_buff *skb, *tmp_skb; 1896 struct sk_buff **tail_skb; 1897 struct in6_addr *final_dst; 1898 struct net *net = sock_net(sk); 1899 struct ipv6hdr *hdr; 1900 struct ipv6_txoptions *opt = v6_cork->opt; 1901 struct rt6_info *rt = dst_rt6_info(cork->base.dst); 1902 struct flowi6 *fl6 = &cork->fl.u.ip6; 1903 unsigned char proto = fl6->flowi6_proto; 1904 1905 skb = __skb_dequeue(queue); 1906 if (!skb) 1907 goto out; 1908 tail_skb = &(skb_shinfo(skb)->frag_list); 1909 1910 /* move skb->data to ip header from ext header */ 1911 if (skb->data < skb_network_header(skb)) 1912 __skb_pull(skb, skb_network_offset(skb)); 1913 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1914 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1915 *tail_skb = tmp_skb; 1916 tail_skb = &(tmp_skb->next); 1917 skb->len += tmp_skb->len; 1918 skb->data_len += tmp_skb->len; 1919 skb->truesize += tmp_skb->truesize; 1920 tmp_skb->destructor = NULL; 1921 tmp_skb->sk = NULL; 1922 } 1923 1924 /* Allow local fragmentation. */ 1925 skb->ignore_df = ip6_sk_ignore_df(sk); 1926 __skb_pull(skb, skb_network_header_len(skb)); 1927 1928 final_dst = &fl6->daddr; 1929 if (opt && opt->opt_flen) 1930 ipv6_push_frag_opts(skb, opt, &proto); 1931 if (opt && opt->opt_nflen) 1932 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1933 1934 skb_push(skb, sizeof(struct ipv6hdr)); 1935 skb_reset_network_header(skb); 1936 hdr = ipv6_hdr(skb); 1937 1938 ip6_flow_hdr(hdr, v6_cork->tclass, 1939 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1940 ip6_autoflowlabel(net, sk), fl6)); 1941 hdr->hop_limit = v6_cork->hop_limit; 1942 hdr->nexthdr = proto; 1943 hdr->saddr = fl6->saddr; 1944 hdr->daddr = *final_dst; 1945 1946 skb->priority = cork->base.priority; 1947 skb->mark = cork->base.mark; 1948 if (sk_is_tcp(sk)) 1949 skb_set_delivery_time(skb, cork->base.transmit_time, SKB_CLOCK_MONOTONIC); 1950 else 1951 skb_set_delivery_type_by_clockid(skb, cork->base.transmit_time, sk->sk_clockid); 1952 1953 ip6_cork_steal_dst(skb, cork); 1954 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS); 1955 if (proto == IPPROTO_ICMPV6) { 1956 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1957 u8 icmp6_type; 1958 1959 if (sk->sk_socket->type == SOCK_RAW && 1960 !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH)) 1961 icmp6_type = fl6->fl6_icmp_type; 1962 else 1963 icmp6_type = icmp6_hdr(skb)->icmp6_type; 1964 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type); 1965 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1966 } 1967 1968 ip6_cork_release(cork, v6_cork); 1969 out: 1970 return skb; 1971 } 1972 1973 int ip6_send_skb(struct sk_buff *skb) 1974 { 1975 struct net *net = sock_net(skb->sk); 1976 struct rt6_info *rt = dst_rt6_info(skb_dst(skb)); 1977 int err; 1978 1979 rcu_read_lock(); 1980 err = ip6_local_out(net, skb->sk, skb); 1981 if (err) { 1982 if (err > 0) 1983 err = net_xmit_errno(err); 1984 if (err) 1985 IP6_INC_STATS(net, rt->rt6i_idev, 1986 IPSTATS_MIB_OUTDISCARDS); 1987 } 1988 1989 rcu_read_unlock(); 1990 return err; 1991 } 1992 1993 int ip6_push_pending_frames(struct sock *sk) 1994 { 1995 struct sk_buff *skb; 1996 1997 skb = ip6_finish_skb(sk); 1998 if (!skb) 1999 return 0; 2000 2001 return ip6_send_skb(skb); 2002 } 2003 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 2004 2005 static void __ip6_flush_pending_frames(struct sock *sk, 2006 struct sk_buff_head *queue, 2007 struct inet_cork_full *cork, 2008 struct inet6_cork *v6_cork) 2009 { 2010 struct sk_buff *skb; 2011 2012 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 2013 if (skb_dst(skb)) 2014 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 2015 IPSTATS_MIB_OUTDISCARDS); 2016 kfree_skb(skb); 2017 } 2018 2019 ip6_cork_release(cork, v6_cork); 2020 } 2021 2022 void ip6_flush_pending_frames(struct sock *sk) 2023 { 2024 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 2025 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 2026 } 2027 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 2028 2029 struct sk_buff *ip6_make_skb(struct sock *sk, 2030 int getfrag(void *from, char *to, int offset, 2031 int len, int odd, struct sk_buff *skb), 2032 void *from, size_t length, int transhdrlen, 2033 struct ipcm6_cookie *ipc6, struct rt6_info *rt, 2034 unsigned int flags, struct inet_cork_full *cork) 2035 { 2036 struct inet6_cork v6_cork; 2037 struct sk_buff_head queue; 2038 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 2039 int err; 2040 2041 if (flags & MSG_PROBE) { 2042 dst_release(&rt->dst); 2043 return NULL; 2044 } 2045 2046 __skb_queue_head_init(&queue); 2047 2048 cork->base.flags = 0; 2049 cork->base.addr = 0; 2050 cork->base.opt = NULL; 2051 v6_cork.opt = NULL; 2052 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt); 2053 if (err) { 2054 ip6_cork_release(cork, &v6_cork); 2055 return ERR_PTR(err); 2056 } 2057 if (ipc6->dontfrag < 0) 2058 ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk); 2059 2060 err = __ip6_append_data(sk, &queue, cork, &v6_cork, 2061 ¤t->task_frag, getfrag, from, 2062 length + exthdrlen, transhdrlen + exthdrlen, 2063 flags, ipc6); 2064 if (err) { 2065 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); 2066 return ERR_PTR(err); 2067 } 2068 2069 return __ip6_make_skb(sk, &queue, cork, &v6_cork); 2070 } 2071