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 (unlikely(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 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1); 617 618 /* Limit redirects both by destination (here) 619 and by source (inside ndisc_send_redirect) 620 */ 621 if (inet_peer_xrlim_allow(peer, 1*HZ)) 622 ndisc_send_redirect(skb, target); 623 if (peer) 624 inet_putpeer(peer); 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 sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags); 1405 1406 cork->base.length = 0; 1407 cork->base.transmit_time = ipc6->sockc.transmit_time; 1408 1409 return 0; 1410 } 1411 1412 static int __ip6_append_data(struct sock *sk, 1413 struct sk_buff_head *queue, 1414 struct inet_cork_full *cork_full, 1415 struct inet6_cork *v6_cork, 1416 struct page_frag *pfrag, 1417 int getfrag(void *from, char *to, int offset, 1418 int len, int odd, struct sk_buff *skb), 1419 void *from, size_t length, int transhdrlen, 1420 unsigned int flags, struct ipcm6_cookie *ipc6) 1421 { 1422 struct sk_buff *skb, *skb_prev = NULL; 1423 struct inet_cork *cork = &cork_full->base; 1424 struct flowi6 *fl6 = &cork_full->fl.u.ip6; 1425 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; 1426 struct ubuf_info *uarg = NULL; 1427 int exthdrlen = 0; 1428 int dst_exthdrlen = 0; 1429 int hh_len; 1430 int copy; 1431 int err; 1432 int offset = 0; 1433 bool zc = false; 1434 u32 tskey = 0; 1435 struct rt6_info *rt = dst_rt6_info(cork->dst); 1436 bool paged, hold_tskey, extra_uref = false; 1437 struct ipv6_txoptions *opt = v6_cork->opt; 1438 int csummode = CHECKSUM_NONE; 1439 unsigned int maxnonfragsize, headersize; 1440 unsigned int wmem_alloc_delta = 0; 1441 1442 skb = skb_peek_tail(queue); 1443 if (!skb) { 1444 exthdrlen = opt ? opt->opt_flen : 0; 1445 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1446 } 1447 1448 paged = !!cork->gso_size; 1449 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize; 1450 orig_mtu = mtu; 1451 1452 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1453 1454 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1455 (opt ? opt->opt_nflen : 0); 1456 1457 headersize = sizeof(struct ipv6hdr) + 1458 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1459 rt->rt6i_nfheader_len; 1460 1461 if (mtu <= fragheaderlen || 1462 ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr)) 1463 goto emsgsize; 1464 1465 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1466 sizeof(struct frag_hdr); 1467 1468 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit 1469 * the first fragment 1470 */ 1471 if (headersize + transhdrlen > mtu) 1472 goto emsgsize; 1473 1474 if (cork->length + length > mtu - headersize && ipc6->dontfrag && 1475 (sk->sk_protocol == IPPROTO_UDP || 1476 sk->sk_protocol == IPPROTO_ICMPV6 || 1477 sk->sk_protocol == IPPROTO_RAW)) { 1478 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1479 sizeof(struct ipv6hdr)); 1480 goto emsgsize; 1481 } 1482 1483 if (ip6_sk_ignore_df(sk)) 1484 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1485 else 1486 maxnonfragsize = mtu; 1487 1488 if (cork->length + length > maxnonfragsize - headersize) { 1489 emsgsize: 1490 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); 1491 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); 1492 return -EMSGSIZE; 1493 } 1494 1495 /* CHECKSUM_PARTIAL only with no extension headers and when 1496 * we are not going to fragment 1497 */ 1498 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1499 headersize == sizeof(struct ipv6hdr) && 1500 length <= mtu - headersize && 1501 (!(flags & MSG_MORE) || cork->gso_size) && 1502 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM)) 1503 csummode = CHECKSUM_PARTIAL; 1504 1505 if ((flags & MSG_ZEROCOPY) && length) { 1506 struct msghdr *msg = from; 1507 1508 if (getfrag == ip_generic_getfrag && msg->msg_ubuf) { 1509 if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb)) 1510 return -EINVAL; 1511 1512 /* Leave uarg NULL if can't zerocopy, callers should 1513 * be able to handle it. 1514 */ 1515 if ((rt->dst.dev->features & NETIF_F_SG) && 1516 csummode == CHECKSUM_PARTIAL) { 1517 paged = true; 1518 zc = true; 1519 uarg = msg->msg_ubuf; 1520 } 1521 } else if (sock_flag(sk, SOCK_ZEROCOPY)) { 1522 uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); 1523 if (!uarg) 1524 return -ENOBUFS; 1525 extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ 1526 if (rt->dst.dev->features & NETIF_F_SG && 1527 csummode == CHECKSUM_PARTIAL) { 1528 paged = true; 1529 zc = true; 1530 } else { 1531 uarg_to_msgzc(uarg)->zerocopy = 0; 1532 skb_zcopy_set(skb, uarg, &extra_uref); 1533 } 1534 } 1535 } else if ((flags & MSG_SPLICE_PAGES) && length) { 1536 if (inet_test_bit(HDRINCL, sk)) 1537 return -EPERM; 1538 if (rt->dst.dev->features & NETIF_F_SG && 1539 getfrag == ip_generic_getfrag) 1540 /* We need an empty buffer to attach stuff to */ 1541 paged = true; 1542 else 1543 flags &= ~MSG_SPLICE_PAGES; 1544 } 1545 1546 hold_tskey = cork->tx_flags & SKBTX_ANY_TSTAMP && 1547 READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID; 1548 if (hold_tskey) 1549 tskey = atomic_inc_return(&sk->sk_tskey) - 1; 1550 1551 /* 1552 * Let's try using as much space as possible. 1553 * Use MTU if total length of the message fits into the MTU. 1554 * Otherwise, we need to reserve fragment header and 1555 * fragment alignment (= 8-15 octects, in total). 1556 * 1557 * Note that we may need to "move" the data from the tail 1558 * of the buffer to the new fragment when we split 1559 * the message. 1560 * 1561 * FIXME: It may be fragmented into multiple chunks 1562 * at once if non-fragmentable extension headers 1563 * are too large. 1564 * --yoshfuji 1565 */ 1566 1567 cork->length += length; 1568 if (!skb) 1569 goto alloc_new_skb; 1570 1571 while (length > 0) { 1572 /* Check if the remaining data fits into current packet. */ 1573 copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len; 1574 if (copy < length) 1575 copy = maxfraglen - skb->len; 1576 1577 if (copy <= 0) { 1578 char *data; 1579 unsigned int datalen; 1580 unsigned int fraglen; 1581 unsigned int fraggap; 1582 unsigned int alloclen, alloc_extra; 1583 unsigned int pagedlen; 1584 alloc_new_skb: 1585 /* There's no room in the current skb */ 1586 if (skb) 1587 fraggap = skb->len - maxfraglen; 1588 else 1589 fraggap = 0; 1590 /* update mtu and maxfraglen if necessary */ 1591 if (!skb || !skb_prev) 1592 ip6_append_data_mtu(&mtu, &maxfraglen, 1593 fragheaderlen, skb, rt, 1594 orig_mtu); 1595 1596 skb_prev = skb; 1597 1598 /* 1599 * If remaining data exceeds the mtu, 1600 * we know we need more fragment(s). 1601 */ 1602 datalen = length + fraggap; 1603 1604 if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen) 1605 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1606 fraglen = datalen + fragheaderlen; 1607 pagedlen = 0; 1608 1609 alloc_extra = hh_len; 1610 alloc_extra += dst_exthdrlen; 1611 alloc_extra += rt->dst.trailer_len; 1612 1613 /* We just reserve space for fragment header. 1614 * Note: this may be overallocation if the message 1615 * (without MSG_MORE) fits into the MTU. 1616 */ 1617 alloc_extra += sizeof(struct frag_hdr); 1618 1619 if ((flags & MSG_MORE) && 1620 !(rt->dst.dev->features&NETIF_F_SG)) 1621 alloclen = mtu; 1622 else if (!paged && 1623 (fraglen + alloc_extra < SKB_MAX_ALLOC || 1624 !(rt->dst.dev->features & NETIF_F_SG))) 1625 alloclen = fraglen; 1626 else { 1627 alloclen = fragheaderlen + transhdrlen; 1628 pagedlen = datalen - transhdrlen; 1629 } 1630 alloclen += alloc_extra; 1631 1632 if (datalen != length + fraggap) { 1633 /* 1634 * this is not the last fragment, the trailer 1635 * space is regarded as data space. 1636 */ 1637 datalen += rt->dst.trailer_len; 1638 } 1639 1640 fraglen = datalen + fragheaderlen; 1641 1642 copy = datalen - transhdrlen - fraggap - pagedlen; 1643 /* [!] NOTE: copy may be negative if pagedlen>0 1644 * because then the equation may reduces to -fraggap. 1645 */ 1646 if (copy < 0 && !(flags & MSG_SPLICE_PAGES)) { 1647 err = -EINVAL; 1648 goto error; 1649 } 1650 if (transhdrlen) { 1651 skb = sock_alloc_send_skb(sk, alloclen, 1652 (flags & MSG_DONTWAIT), &err); 1653 } else { 1654 skb = NULL; 1655 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 1656 2 * sk->sk_sndbuf) 1657 skb = alloc_skb(alloclen, 1658 sk->sk_allocation); 1659 if (unlikely(!skb)) 1660 err = -ENOBUFS; 1661 } 1662 if (!skb) 1663 goto error; 1664 /* 1665 * Fill in the control structures 1666 */ 1667 skb->protocol = htons(ETH_P_IPV6); 1668 skb->ip_summed = csummode; 1669 skb->csum = 0; 1670 /* reserve for fragmentation and ipsec header */ 1671 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1672 dst_exthdrlen); 1673 1674 /* 1675 * Find where to start putting bytes 1676 */ 1677 data = skb_put(skb, fraglen - pagedlen); 1678 skb_set_network_header(skb, exthdrlen); 1679 data += fragheaderlen; 1680 skb->transport_header = (skb->network_header + 1681 fragheaderlen); 1682 if (fraggap) { 1683 skb->csum = skb_copy_and_csum_bits( 1684 skb_prev, maxfraglen, 1685 data + transhdrlen, fraggap); 1686 skb_prev->csum = csum_sub(skb_prev->csum, 1687 skb->csum); 1688 data += fraggap; 1689 pskb_trim_unique(skb_prev, maxfraglen); 1690 } 1691 if (copy > 0 && 1692 getfrag(from, data + transhdrlen, offset, 1693 copy, fraggap, skb) < 0) { 1694 err = -EFAULT; 1695 kfree_skb(skb); 1696 goto error; 1697 } else if (flags & MSG_SPLICE_PAGES) { 1698 copy = 0; 1699 } 1700 1701 offset += copy; 1702 length -= copy + transhdrlen; 1703 transhdrlen = 0; 1704 exthdrlen = 0; 1705 dst_exthdrlen = 0; 1706 1707 /* Only the initial fragment is time stamped */ 1708 skb_shinfo(skb)->tx_flags = cork->tx_flags; 1709 cork->tx_flags = 0; 1710 skb_shinfo(skb)->tskey = tskey; 1711 tskey = 0; 1712 skb_zcopy_set(skb, uarg, &extra_uref); 1713 1714 if ((flags & MSG_CONFIRM) && !skb_prev) 1715 skb_set_dst_pending_confirm(skb, 1); 1716 1717 /* 1718 * Put the packet on the pending queue 1719 */ 1720 if (!skb->destructor) { 1721 skb->destructor = sock_wfree; 1722 skb->sk = sk; 1723 wmem_alloc_delta += skb->truesize; 1724 } 1725 __skb_queue_tail(queue, skb); 1726 continue; 1727 } 1728 1729 if (copy > length) 1730 copy = length; 1731 1732 if (!(rt->dst.dev->features&NETIF_F_SG) && 1733 skb_tailroom(skb) >= copy) { 1734 unsigned int off; 1735 1736 off = skb->len; 1737 if (getfrag(from, skb_put(skb, copy), 1738 offset, copy, off, skb) < 0) { 1739 __skb_trim(skb, off); 1740 err = -EFAULT; 1741 goto error; 1742 } 1743 } else if (flags & MSG_SPLICE_PAGES) { 1744 struct msghdr *msg = from; 1745 1746 err = -EIO; 1747 if (WARN_ON_ONCE(copy > msg->msg_iter.count)) 1748 goto error; 1749 1750 err = skb_splice_from_iter(skb, &msg->msg_iter, copy, 1751 sk->sk_allocation); 1752 if (err < 0) 1753 goto error; 1754 copy = err; 1755 wmem_alloc_delta += copy; 1756 } else if (!zc) { 1757 int i = skb_shinfo(skb)->nr_frags; 1758 1759 err = -ENOMEM; 1760 if (!sk_page_frag_refill(sk, pfrag)) 1761 goto error; 1762 1763 skb_zcopy_downgrade_managed(skb); 1764 if (!skb_can_coalesce(skb, i, pfrag->page, 1765 pfrag->offset)) { 1766 err = -EMSGSIZE; 1767 if (i == MAX_SKB_FRAGS) 1768 goto error; 1769 1770 __skb_fill_page_desc(skb, i, pfrag->page, 1771 pfrag->offset, 0); 1772 skb_shinfo(skb)->nr_frags = ++i; 1773 get_page(pfrag->page); 1774 } 1775 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1776 if (getfrag(from, 1777 page_address(pfrag->page) + pfrag->offset, 1778 offset, copy, skb->len, skb) < 0) 1779 goto error_efault; 1780 1781 pfrag->offset += copy; 1782 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1783 skb->len += copy; 1784 skb->data_len += copy; 1785 skb->truesize += copy; 1786 wmem_alloc_delta += copy; 1787 } else { 1788 err = skb_zerocopy_iter_dgram(skb, from, copy); 1789 if (err < 0) 1790 goto error; 1791 } 1792 offset += copy; 1793 length -= copy; 1794 } 1795 1796 if (wmem_alloc_delta) 1797 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1798 return 0; 1799 1800 error_efault: 1801 err = -EFAULT; 1802 error: 1803 net_zcopy_put_abort(uarg, extra_uref); 1804 cork->length -= length; 1805 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1806 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1807 if (hold_tskey) 1808 atomic_dec(&sk->sk_tskey); 1809 return err; 1810 } 1811 1812 int ip6_append_data(struct sock *sk, 1813 int getfrag(void *from, char *to, int offset, int len, 1814 int odd, struct sk_buff *skb), 1815 void *from, size_t length, int transhdrlen, 1816 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1817 struct rt6_info *rt, unsigned int flags) 1818 { 1819 struct inet_sock *inet = inet_sk(sk); 1820 struct ipv6_pinfo *np = inet6_sk(sk); 1821 int exthdrlen; 1822 int err; 1823 1824 if (flags&MSG_PROBE) 1825 return 0; 1826 if (skb_queue_empty(&sk->sk_write_queue)) { 1827 /* 1828 * setup for corking 1829 */ 1830 dst_hold(&rt->dst); 1831 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1832 ipc6, rt); 1833 if (err) 1834 return err; 1835 1836 inet->cork.fl.u.ip6 = *fl6; 1837 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1838 length += exthdrlen; 1839 transhdrlen += exthdrlen; 1840 } else { 1841 transhdrlen = 0; 1842 } 1843 1844 return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork, 1845 &np->cork, sk_page_frag(sk), getfrag, 1846 from, length, transhdrlen, flags, ipc6); 1847 } 1848 EXPORT_SYMBOL_GPL(ip6_append_data); 1849 1850 static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork) 1851 { 1852 struct dst_entry *dst = cork->base.dst; 1853 1854 cork->base.dst = NULL; 1855 skb_dst_set(skb, dst); 1856 } 1857 1858 static void ip6_cork_release(struct inet_cork_full *cork, 1859 struct inet6_cork *v6_cork) 1860 { 1861 if (v6_cork->opt) { 1862 struct ipv6_txoptions *opt = v6_cork->opt; 1863 1864 kfree(opt->dst0opt); 1865 kfree(opt->dst1opt); 1866 kfree(opt->hopopt); 1867 kfree(opt->srcrt); 1868 kfree(opt); 1869 v6_cork->opt = NULL; 1870 } 1871 1872 if (cork->base.dst) { 1873 dst_release(cork->base.dst); 1874 cork->base.dst = NULL; 1875 } 1876 } 1877 1878 struct sk_buff *__ip6_make_skb(struct sock *sk, 1879 struct sk_buff_head *queue, 1880 struct inet_cork_full *cork, 1881 struct inet6_cork *v6_cork) 1882 { 1883 struct sk_buff *skb, *tmp_skb; 1884 struct sk_buff **tail_skb; 1885 struct in6_addr *final_dst; 1886 struct net *net = sock_net(sk); 1887 struct ipv6hdr *hdr; 1888 struct ipv6_txoptions *opt = v6_cork->opt; 1889 struct rt6_info *rt = dst_rt6_info(cork->base.dst); 1890 struct flowi6 *fl6 = &cork->fl.u.ip6; 1891 unsigned char proto = fl6->flowi6_proto; 1892 1893 skb = __skb_dequeue(queue); 1894 if (!skb) 1895 goto out; 1896 tail_skb = &(skb_shinfo(skb)->frag_list); 1897 1898 /* move skb->data to ip header from ext header */ 1899 if (skb->data < skb_network_header(skb)) 1900 __skb_pull(skb, skb_network_offset(skb)); 1901 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1902 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1903 *tail_skb = tmp_skb; 1904 tail_skb = &(tmp_skb->next); 1905 skb->len += tmp_skb->len; 1906 skb->data_len += tmp_skb->len; 1907 skb->truesize += tmp_skb->truesize; 1908 tmp_skb->destructor = NULL; 1909 tmp_skb->sk = NULL; 1910 } 1911 1912 /* Allow local fragmentation. */ 1913 skb->ignore_df = ip6_sk_ignore_df(sk); 1914 __skb_pull(skb, skb_network_header_len(skb)); 1915 1916 final_dst = &fl6->daddr; 1917 if (opt && opt->opt_flen) 1918 ipv6_push_frag_opts(skb, opt, &proto); 1919 if (opt && opt->opt_nflen) 1920 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1921 1922 skb_push(skb, sizeof(struct ipv6hdr)); 1923 skb_reset_network_header(skb); 1924 hdr = ipv6_hdr(skb); 1925 1926 ip6_flow_hdr(hdr, v6_cork->tclass, 1927 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1928 ip6_autoflowlabel(net, sk), fl6)); 1929 hdr->hop_limit = v6_cork->hop_limit; 1930 hdr->nexthdr = proto; 1931 hdr->saddr = fl6->saddr; 1932 hdr->daddr = *final_dst; 1933 1934 skb->priority = READ_ONCE(sk->sk_priority); 1935 skb->mark = cork->base.mark; 1936 if (sk_is_tcp(sk)) 1937 skb_set_delivery_time(skb, cork->base.transmit_time, SKB_CLOCK_MONOTONIC); 1938 else 1939 skb_set_delivery_type_by_clockid(skb, cork->base.transmit_time, sk->sk_clockid); 1940 1941 ip6_cork_steal_dst(skb, cork); 1942 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS); 1943 if (proto == IPPROTO_ICMPV6) { 1944 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1945 u8 icmp6_type; 1946 1947 if (sk->sk_socket->type == SOCK_RAW && 1948 !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH)) 1949 icmp6_type = fl6->fl6_icmp_type; 1950 else 1951 icmp6_type = icmp6_hdr(skb)->icmp6_type; 1952 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type); 1953 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1954 } 1955 1956 ip6_cork_release(cork, v6_cork); 1957 out: 1958 return skb; 1959 } 1960 1961 int ip6_send_skb(struct sk_buff *skb) 1962 { 1963 struct net *net = sock_net(skb->sk); 1964 struct rt6_info *rt = dst_rt6_info(skb_dst(skb)); 1965 int err; 1966 1967 rcu_read_lock(); 1968 err = ip6_local_out(net, skb->sk, skb); 1969 if (err) { 1970 if (err > 0) 1971 err = net_xmit_errno(err); 1972 if (err) 1973 IP6_INC_STATS(net, rt->rt6i_idev, 1974 IPSTATS_MIB_OUTDISCARDS); 1975 } 1976 1977 rcu_read_unlock(); 1978 return err; 1979 } 1980 1981 int ip6_push_pending_frames(struct sock *sk) 1982 { 1983 struct sk_buff *skb; 1984 1985 skb = ip6_finish_skb(sk); 1986 if (!skb) 1987 return 0; 1988 1989 return ip6_send_skb(skb); 1990 } 1991 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1992 1993 static void __ip6_flush_pending_frames(struct sock *sk, 1994 struct sk_buff_head *queue, 1995 struct inet_cork_full *cork, 1996 struct inet6_cork *v6_cork) 1997 { 1998 struct sk_buff *skb; 1999 2000 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 2001 if (skb_dst(skb)) 2002 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 2003 IPSTATS_MIB_OUTDISCARDS); 2004 kfree_skb(skb); 2005 } 2006 2007 ip6_cork_release(cork, v6_cork); 2008 } 2009 2010 void ip6_flush_pending_frames(struct sock *sk) 2011 { 2012 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 2013 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 2014 } 2015 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 2016 2017 struct sk_buff *ip6_make_skb(struct sock *sk, 2018 int getfrag(void *from, char *to, int offset, 2019 int len, int odd, struct sk_buff *skb), 2020 void *from, size_t length, int transhdrlen, 2021 struct ipcm6_cookie *ipc6, struct rt6_info *rt, 2022 unsigned int flags, struct inet_cork_full *cork) 2023 { 2024 struct inet6_cork v6_cork; 2025 struct sk_buff_head queue; 2026 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 2027 int err; 2028 2029 if (flags & MSG_PROBE) { 2030 dst_release(&rt->dst); 2031 return NULL; 2032 } 2033 2034 __skb_queue_head_init(&queue); 2035 2036 cork->base.flags = 0; 2037 cork->base.addr = 0; 2038 cork->base.opt = NULL; 2039 v6_cork.opt = NULL; 2040 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt); 2041 if (err) { 2042 ip6_cork_release(cork, &v6_cork); 2043 return ERR_PTR(err); 2044 } 2045 if (ipc6->dontfrag < 0) 2046 ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk); 2047 2048 err = __ip6_append_data(sk, &queue, cork, &v6_cork, 2049 ¤t->task_frag, getfrag, from, 2050 length + exthdrlen, transhdrlen + exthdrlen, 2051 flags, ipc6); 2052 if (err) { 2053 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); 2054 return ERR_PTR(err); 2055 } 2056 2057 return __ip6_make_skb(sk, &queue, cork, &v6_cork); 2058 } 2059