1 /* 2 * IPv6 output functions 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * Based on linux/net/ipv4/ip_output.c 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 * 15 * Changes: 16 * A.N.Kuznetsov : airthmetics in fragmentation. 17 * extension headers are implemented. 18 * route changes now work. 19 * ip6_forward does not confuse sniffers. 20 * etc. 21 * 22 * H. von Brand : Added missing #include <linux/string.h> 23 * Imran Patel : frag id should be in NBO 24 * Kazunori MIYAZAWA @USAGI 25 * : add ip6_append_data and related functions 26 * for datagram xmit 27 */ 28 29 #include <linux/errno.h> 30 #include <linux/kernel.h> 31 #include <linux/string.h> 32 #include <linux/socket.h> 33 #include <linux/net.h> 34 #include <linux/netdevice.h> 35 #include <linux/if_arp.h> 36 #include <linux/in6.h> 37 #include <linux/tcp.h> 38 #include <linux/route.h> 39 #include <linux/module.h> 40 #include <linux/slab.h> 41 42 #include <linux/bpf-cgroup.h> 43 #include <linux/netfilter.h> 44 #include <linux/netfilter_ipv6.h> 45 46 #include <net/sock.h> 47 #include <net/snmp.h> 48 49 #include <net/ipv6.h> 50 #include <net/ndisc.h> 51 #include <net/protocol.h> 52 #include <net/ip6_route.h> 53 #include <net/addrconf.h> 54 #include <net/rawv6.h> 55 #include <net/icmp.h> 56 #include <net/xfrm.h> 57 #include <net/checksum.h> 58 #include <linux/mroute6.h> 59 #include <net/l3mdev.h> 60 #include <net/lwtunnel.h> 61 62 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) 63 { 64 struct dst_entry *dst = skb_dst(skb); 65 struct net_device *dev = dst->dev; 66 struct neighbour *neigh; 67 struct in6_addr *nexthop; 68 int ret; 69 70 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { 71 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 72 73 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) && 74 ((mroute6_is_socket(net, skb) && 75 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 76 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, 77 &ipv6_hdr(skb)->saddr))) { 78 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 79 80 /* Do not check for IFF_ALLMULTI; multicast routing 81 is not supported in any case. 82 */ 83 if (newskb) 84 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 85 net, sk, newskb, NULL, newskb->dev, 86 dev_loopback_xmit); 87 88 if (ipv6_hdr(skb)->hop_limit == 0) { 89 IP6_INC_STATS(net, idev, 90 IPSTATS_MIB_OUTDISCARDS); 91 kfree_skb(skb); 92 return 0; 93 } 94 } 95 96 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len); 97 98 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <= 99 IPV6_ADDR_SCOPE_NODELOCAL && 100 !(dev->flags & IFF_LOOPBACK)) { 101 kfree_skb(skb); 102 return 0; 103 } 104 } 105 106 if (lwtunnel_xmit_redirect(dst->lwtstate)) { 107 int res = lwtunnel_xmit(skb); 108 109 if (res < 0 || res == LWTUNNEL_XMIT_DONE) 110 return res; 111 } 112 113 rcu_read_lock_bh(); 114 nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr); 115 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop); 116 if (unlikely(!neigh)) 117 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false); 118 if (!IS_ERR(neigh)) { 119 sock_confirm_neigh(skb, neigh); 120 ret = neigh_output(neigh, skb); 121 rcu_read_unlock_bh(); 122 return ret; 123 } 124 rcu_read_unlock_bh(); 125 126 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 127 kfree_skb(skb); 128 return -EINVAL; 129 } 130 131 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) 132 { 133 int ret; 134 135 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); 136 if (ret) { 137 kfree_skb(skb); 138 return ret; 139 } 140 141 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 142 /* Policy lookup after SNAT yielded a new policy */ 143 if (skb_dst(skb)->xfrm) { 144 IPCB(skb)->flags |= IPSKB_REROUTED; 145 return dst_output(net, sk, skb); 146 } 147 #endif 148 149 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || 150 dst_allfrag(skb_dst(skb)) || 151 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size)) 152 return ip6_fragment(net, sk, skb, ip6_finish_output2); 153 else 154 return ip6_finish_output2(net, sk, skb); 155 } 156 157 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 158 { 159 struct net_device *dev = skb_dst(skb)->dev; 160 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 161 162 skb->protocol = htons(ETH_P_IPV6); 163 skb->dev = dev; 164 165 if (unlikely(idev->cnf.disable_ipv6)) { 166 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 167 kfree_skb(skb); 168 return 0; 169 } 170 171 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 172 net, sk, skb, NULL, dev, 173 ip6_finish_output, 174 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 175 } 176 177 bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np) 178 { 179 if (!np->autoflowlabel_set) 180 return ip6_default_np_autolabel(net); 181 else 182 return np->autoflowlabel; 183 } 184 185 /* 186 * xmit an sk_buff (used by TCP, SCTP and DCCP) 187 * Note : socket lock is not held for SYNACK packets, but might be modified 188 * by calls to skb_set_owner_w() and ipv6_local_error(), 189 * which are using proper atomic operations or spinlocks. 190 */ 191 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 192 __u32 mark, struct ipv6_txoptions *opt, int tclass) 193 { 194 struct net *net = sock_net(sk); 195 const struct ipv6_pinfo *np = inet6_sk(sk); 196 struct in6_addr *first_hop = &fl6->daddr; 197 struct dst_entry *dst = skb_dst(skb); 198 struct ipv6hdr *hdr; 199 u8 proto = fl6->flowi6_proto; 200 int seg_len = skb->len; 201 int hlimit = -1; 202 u32 mtu; 203 204 if (opt) { 205 unsigned int head_room; 206 207 /* First: exthdrs may take lots of space (~8K for now) 208 MAX_HEADER is not enough. 209 */ 210 head_room = opt->opt_nflen + opt->opt_flen; 211 seg_len += head_room; 212 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 213 214 if (skb_headroom(skb) < head_room) { 215 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 216 if (!skb2) { 217 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 218 IPSTATS_MIB_OUTDISCARDS); 219 kfree_skb(skb); 220 return -ENOBUFS; 221 } 222 consume_skb(skb); 223 skb = skb2; 224 /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically, 225 * it is safe to call in our context (socket lock not held) 226 */ 227 skb_set_owner_w(skb, (struct sock *)sk); 228 } 229 if (opt->opt_flen) 230 ipv6_push_frag_opts(skb, opt, &proto); 231 if (opt->opt_nflen) 232 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop, 233 &fl6->saddr); 234 } 235 236 skb_push(skb, sizeof(struct ipv6hdr)); 237 skb_reset_network_header(skb); 238 hdr = ipv6_hdr(skb); 239 240 /* 241 * Fill in the IPv6 header 242 */ 243 if (np) 244 hlimit = np->hop_limit; 245 if (hlimit < 0) 246 hlimit = ip6_dst_hoplimit(dst); 247 248 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 249 ip6_autoflowlabel(net, np), fl6)); 250 251 hdr->payload_len = htons(seg_len); 252 hdr->nexthdr = proto; 253 hdr->hop_limit = hlimit; 254 255 hdr->saddr = fl6->saddr; 256 hdr->daddr = *first_hop; 257 258 skb->protocol = htons(ETH_P_IPV6); 259 skb->priority = sk->sk_priority; 260 skb->mark = mark; 261 262 mtu = dst_mtu(dst); 263 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 264 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 265 IPSTATS_MIB_OUT, skb->len); 266 267 /* if egress device is enslaved to an L3 master device pass the 268 * skb to its handler for processing 269 */ 270 skb = l3mdev_ip6_out((struct sock *)sk, skb); 271 if (unlikely(!skb)) 272 return 0; 273 274 /* hooks should never assume socket lock is held. 275 * we promote our socket to non const 276 */ 277 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 278 net, (struct sock *)sk, skb, NULL, dst->dev, 279 dst_output); 280 } 281 282 skb->dev = dst->dev; 283 /* ipv6_local_error() does not require socket lock, 284 * we promote our socket to non const 285 */ 286 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu); 287 288 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 289 kfree_skb(skb); 290 return -EMSGSIZE; 291 } 292 EXPORT_SYMBOL(ip6_xmit); 293 294 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 295 { 296 struct ip6_ra_chain *ra; 297 struct sock *last = NULL; 298 299 read_lock(&ip6_ra_lock); 300 for (ra = ip6_ra_chain; ra; ra = ra->next) { 301 struct sock *sk = ra->sk; 302 if (sk && ra->sel == sel && 303 (!sk->sk_bound_dev_if || 304 sk->sk_bound_dev_if == skb->dev->ifindex)) { 305 if (last) { 306 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 307 if (skb2) 308 rawv6_rcv(last, skb2); 309 } 310 last = sk; 311 } 312 } 313 314 if (last) { 315 rawv6_rcv(last, skb); 316 read_unlock(&ip6_ra_lock); 317 return 1; 318 } 319 read_unlock(&ip6_ra_lock); 320 return 0; 321 } 322 323 static int ip6_forward_proxy_check(struct sk_buff *skb) 324 { 325 struct ipv6hdr *hdr = ipv6_hdr(skb); 326 u8 nexthdr = hdr->nexthdr; 327 __be16 frag_off; 328 int offset; 329 330 if (ipv6_ext_hdr(nexthdr)) { 331 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 332 if (offset < 0) 333 return 0; 334 } else 335 offset = sizeof(struct ipv6hdr); 336 337 if (nexthdr == IPPROTO_ICMPV6) { 338 struct icmp6hdr *icmp6; 339 340 if (!pskb_may_pull(skb, (skb_network_header(skb) + 341 offset + 1 - skb->data))) 342 return 0; 343 344 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 345 346 switch (icmp6->icmp6_type) { 347 case NDISC_ROUTER_SOLICITATION: 348 case NDISC_ROUTER_ADVERTISEMENT: 349 case NDISC_NEIGHBOUR_SOLICITATION: 350 case NDISC_NEIGHBOUR_ADVERTISEMENT: 351 case NDISC_REDIRECT: 352 /* For reaction involving unicast neighbor discovery 353 * message destined to the proxied address, pass it to 354 * input function. 355 */ 356 return 1; 357 default: 358 break; 359 } 360 } 361 362 /* 363 * The proxying router can't forward traffic sent to a link-local 364 * address, so signal the sender and discard the packet. This 365 * behavior is clarified by the MIPv6 specification. 366 */ 367 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 368 dst_link_failure(skb); 369 return -1; 370 } 371 372 return 0; 373 } 374 375 static inline int ip6_forward_finish(struct net *net, struct sock *sk, 376 struct sk_buff *skb) 377 { 378 struct dst_entry *dst = skb_dst(skb); 379 380 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 381 __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 382 383 return dst_output(net, sk, skb); 384 } 385 386 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 387 { 388 if (skb->len <= mtu) 389 return false; 390 391 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 392 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 393 return true; 394 395 if (skb->ignore_df) 396 return false; 397 398 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu)) 399 return false; 400 401 return true; 402 } 403 404 int ip6_forward(struct sk_buff *skb) 405 { 406 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev); 407 struct dst_entry *dst = skb_dst(skb); 408 struct ipv6hdr *hdr = ipv6_hdr(skb); 409 struct inet6_skb_parm *opt = IP6CB(skb); 410 struct net *net = dev_net(dst->dev); 411 u32 mtu; 412 413 if (net->ipv6.devconf_all->forwarding == 0) 414 goto error; 415 416 if (skb->pkt_type != PACKET_HOST) 417 goto drop; 418 419 if (unlikely(skb->sk)) 420 goto drop; 421 422 if (skb_warn_if_lro(skb)) 423 goto drop; 424 425 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 426 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 427 goto drop; 428 } 429 430 skb_forward_csum(skb); 431 432 /* 433 * We DO NOT make any processing on 434 * RA packets, pushing them to user level AS IS 435 * without ane WARRANTY that application will be able 436 * to interpret them. The reason is that we 437 * cannot make anything clever here. 438 * 439 * We are not end-node, so that if packet contains 440 * AH/ESP, we cannot make anything. 441 * Defragmentation also would be mistake, RA packets 442 * cannot be fragmented, because there is no warranty 443 * that different fragments will go along one path. --ANK 444 */ 445 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 446 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 447 return 0; 448 } 449 450 /* 451 * check and decrement ttl 452 */ 453 if (hdr->hop_limit <= 1) { 454 /* Force OUTPUT device used as source address */ 455 skb->dev = dst->dev; 456 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 457 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 458 459 kfree_skb(skb); 460 return -ETIMEDOUT; 461 } 462 463 /* XXX: idev->cnf.proxy_ndp? */ 464 if (net->ipv6.devconf_all->proxy_ndp && 465 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 466 int proxied = ip6_forward_proxy_check(skb); 467 if (proxied > 0) 468 return ip6_input(skb); 469 else if (proxied < 0) { 470 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 471 goto drop; 472 } 473 } 474 475 if (!xfrm6_route_forward(skb)) { 476 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 477 goto drop; 478 } 479 dst = skb_dst(skb); 480 481 /* IPv6 specs say nothing about it, but it is clear that we cannot 482 send redirects to source routed frames. 483 We don't send redirects to frames decapsulated from IPsec. 484 */ 485 if (IP6CB(skb)->iif == dst->dev->ifindex && 486 opt->srcrt == 0 && !skb_sec_path(skb)) { 487 struct in6_addr *target = NULL; 488 struct inet_peer *peer; 489 struct rt6_info *rt; 490 491 /* 492 * incoming and outgoing devices are the same 493 * send a redirect. 494 */ 495 496 rt = (struct rt6_info *) dst; 497 if (rt->rt6i_flags & RTF_GATEWAY) 498 target = &rt->rt6i_gateway; 499 else 500 target = &hdr->daddr; 501 502 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1); 503 504 /* Limit redirects both by destination (here) 505 and by source (inside ndisc_send_redirect) 506 */ 507 if (inet_peer_xrlim_allow(peer, 1*HZ)) 508 ndisc_send_redirect(skb, target); 509 if (peer) 510 inet_putpeer(peer); 511 } else { 512 int addrtype = ipv6_addr_type(&hdr->saddr); 513 514 /* This check is security critical. */ 515 if (addrtype == IPV6_ADDR_ANY || 516 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 517 goto error; 518 if (addrtype & IPV6_ADDR_LINKLOCAL) { 519 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 520 ICMPV6_NOT_NEIGHBOUR, 0); 521 goto error; 522 } 523 } 524 525 mtu = ip6_dst_mtu_forward(dst); 526 if (mtu < IPV6_MIN_MTU) 527 mtu = IPV6_MIN_MTU; 528 529 if (ip6_pkt_too_big(skb, mtu)) { 530 /* Again, force OUTPUT device used as source address */ 531 skb->dev = dst->dev; 532 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 533 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS); 534 __IP6_INC_STATS(net, ip6_dst_idev(dst), 535 IPSTATS_MIB_FRAGFAILS); 536 kfree_skb(skb); 537 return -EMSGSIZE; 538 } 539 540 if (skb_cow(skb, dst->dev->hard_header_len)) { 541 __IP6_INC_STATS(net, ip6_dst_idev(dst), 542 IPSTATS_MIB_OUTDISCARDS); 543 goto drop; 544 } 545 546 hdr = ipv6_hdr(skb); 547 548 /* Mangling hops number delayed to point after skb COW */ 549 550 hdr->hop_limit--; 551 552 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, 553 net, NULL, skb, skb->dev, dst->dev, 554 ip6_forward_finish); 555 556 error: 557 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 558 drop: 559 kfree_skb(skb); 560 return -EINVAL; 561 } 562 563 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 564 { 565 to->pkt_type = from->pkt_type; 566 to->priority = from->priority; 567 to->protocol = from->protocol; 568 skb_dst_drop(to); 569 skb_dst_set(to, dst_clone(skb_dst(from))); 570 to->dev = from->dev; 571 to->mark = from->mark; 572 573 #ifdef CONFIG_NET_SCHED 574 to->tc_index = from->tc_index; 575 #endif 576 nf_copy(to, from); 577 skb_copy_secmark(to, from); 578 } 579 580 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, 581 int (*output)(struct net *, struct sock *, struct sk_buff *)) 582 { 583 struct sk_buff *frag; 584 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 585 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ? 586 inet6_sk(skb->sk) : NULL; 587 struct ipv6hdr *tmp_hdr; 588 struct frag_hdr *fh; 589 unsigned int mtu, hlen, left, len; 590 int hroom, troom; 591 __be32 frag_id; 592 int ptr, offset = 0, err = 0; 593 u8 *prevhdr, nexthdr = 0; 594 595 err = ip6_find_1stfragopt(skb, &prevhdr); 596 if (err < 0) 597 goto fail; 598 hlen = err; 599 nexthdr = *prevhdr; 600 601 mtu = ip6_skb_dst_mtu(skb); 602 603 /* We must not fragment if the socket is set to force MTU discovery 604 * or if the skb it not generated by a local socket. 605 */ 606 if (unlikely(!skb->ignore_df && skb->len > mtu)) 607 goto fail_toobig; 608 609 if (IP6CB(skb)->frag_max_size) { 610 if (IP6CB(skb)->frag_max_size > mtu) 611 goto fail_toobig; 612 613 /* don't send fragments larger than what we received */ 614 mtu = IP6CB(skb)->frag_max_size; 615 if (mtu < IPV6_MIN_MTU) 616 mtu = IPV6_MIN_MTU; 617 } 618 619 if (np && np->frag_size < mtu) { 620 if (np->frag_size) 621 mtu = np->frag_size; 622 } 623 if (mtu < hlen + sizeof(struct frag_hdr) + 8) 624 goto fail_toobig; 625 mtu -= hlen + sizeof(struct frag_hdr); 626 627 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, 628 &ipv6_hdr(skb)->saddr); 629 630 if (skb->ip_summed == CHECKSUM_PARTIAL && 631 (err = skb_checksum_help(skb))) 632 goto fail; 633 634 hroom = LL_RESERVED_SPACE(rt->dst.dev); 635 if (skb_has_frag_list(skb)) { 636 unsigned int first_len = skb_pagelen(skb); 637 struct sk_buff *frag2; 638 639 if (first_len - hlen > mtu || 640 ((first_len - hlen) & 7) || 641 skb_cloned(skb) || 642 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr))) 643 goto slow_path; 644 645 skb_walk_frags(skb, frag) { 646 /* Correct geometry. */ 647 if (frag->len > mtu || 648 ((frag->len & 7) && frag->next) || 649 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr))) 650 goto slow_path_clean; 651 652 /* Partially cloned skb? */ 653 if (skb_shared(frag)) 654 goto slow_path_clean; 655 656 BUG_ON(frag->sk); 657 if (skb->sk) { 658 frag->sk = skb->sk; 659 frag->destructor = sock_wfree; 660 } 661 skb->truesize -= frag->truesize; 662 } 663 664 err = 0; 665 offset = 0; 666 /* BUILD HEADER */ 667 668 *prevhdr = NEXTHDR_FRAGMENT; 669 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); 670 if (!tmp_hdr) { 671 err = -ENOMEM; 672 goto fail; 673 } 674 frag = skb_shinfo(skb)->frag_list; 675 skb_frag_list_init(skb); 676 677 __skb_pull(skb, hlen); 678 fh = __skb_push(skb, sizeof(struct frag_hdr)); 679 __skb_push(skb, hlen); 680 skb_reset_network_header(skb); 681 memcpy(skb_network_header(skb), tmp_hdr, hlen); 682 683 fh->nexthdr = nexthdr; 684 fh->reserved = 0; 685 fh->frag_off = htons(IP6_MF); 686 fh->identification = frag_id; 687 688 first_len = skb_pagelen(skb); 689 skb->data_len = first_len - skb_headlen(skb); 690 skb->len = first_len; 691 ipv6_hdr(skb)->payload_len = htons(first_len - 692 sizeof(struct ipv6hdr)); 693 694 for (;;) { 695 /* Prepare header of the next frame, 696 * before previous one went down. */ 697 if (frag) { 698 frag->ip_summed = CHECKSUM_NONE; 699 skb_reset_transport_header(frag); 700 fh = __skb_push(frag, sizeof(struct frag_hdr)); 701 __skb_push(frag, hlen); 702 skb_reset_network_header(frag); 703 memcpy(skb_network_header(frag), tmp_hdr, 704 hlen); 705 offset += skb->len - hlen - sizeof(struct frag_hdr); 706 fh->nexthdr = nexthdr; 707 fh->reserved = 0; 708 fh->frag_off = htons(offset); 709 if (frag->next) 710 fh->frag_off |= htons(IP6_MF); 711 fh->identification = frag_id; 712 ipv6_hdr(frag)->payload_len = 713 htons(frag->len - 714 sizeof(struct ipv6hdr)); 715 ip6_copy_metadata(frag, skb); 716 } 717 718 err = output(net, sk, skb); 719 if (!err) 720 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 721 IPSTATS_MIB_FRAGCREATES); 722 723 if (err || !frag) 724 break; 725 726 skb = frag; 727 frag = skb->next; 728 skb->next = NULL; 729 } 730 731 kfree(tmp_hdr); 732 733 if (err == 0) { 734 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 735 IPSTATS_MIB_FRAGOKS); 736 return 0; 737 } 738 739 kfree_skb_list(frag); 740 741 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst), 742 IPSTATS_MIB_FRAGFAILS); 743 return err; 744 745 slow_path_clean: 746 skb_walk_frags(skb, frag2) { 747 if (frag2 == frag) 748 break; 749 frag2->sk = NULL; 750 frag2->destructor = NULL; 751 skb->truesize += frag2->truesize; 752 } 753 } 754 755 slow_path: 756 left = skb->len - hlen; /* Space per frame */ 757 ptr = hlen; /* Where to start from */ 758 759 /* 760 * Fragment the datagram. 761 */ 762 763 troom = rt->dst.dev->needed_tailroom; 764 765 /* 766 * Keep copying data until we run out. 767 */ 768 while (left > 0) { 769 u8 *fragnexthdr_offset; 770 771 len = left; 772 /* IF: it doesn't fit, use 'mtu' - the data space left */ 773 if (len > mtu) 774 len = mtu; 775 /* IF: we are not sending up to and including the packet end 776 then align the next start on an eight byte boundary */ 777 if (len < left) { 778 len &= ~7; 779 } 780 781 /* Allocate buffer */ 782 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) + 783 hroom + troom, GFP_ATOMIC); 784 if (!frag) { 785 err = -ENOMEM; 786 goto fail; 787 } 788 789 /* 790 * Set up data on packet 791 */ 792 793 ip6_copy_metadata(frag, skb); 794 skb_reserve(frag, hroom); 795 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 796 skb_reset_network_header(frag); 797 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); 798 frag->transport_header = (frag->network_header + hlen + 799 sizeof(struct frag_hdr)); 800 801 /* 802 * Charge the memory for the fragment to any owner 803 * it might possess 804 */ 805 if (skb->sk) 806 skb_set_owner_w(frag, skb->sk); 807 808 /* 809 * Copy the packet header into the new buffer. 810 */ 811 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); 812 813 fragnexthdr_offset = skb_network_header(frag); 814 fragnexthdr_offset += prevhdr - skb_network_header(skb); 815 *fragnexthdr_offset = NEXTHDR_FRAGMENT; 816 817 /* 818 * Build fragment header. 819 */ 820 fh->nexthdr = nexthdr; 821 fh->reserved = 0; 822 fh->identification = frag_id; 823 824 /* 825 * Copy a block of the IP datagram. 826 */ 827 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag), 828 len)); 829 left -= len; 830 831 fh->frag_off = htons(offset); 832 if (left > 0) 833 fh->frag_off |= htons(IP6_MF); 834 ipv6_hdr(frag)->payload_len = htons(frag->len - 835 sizeof(struct ipv6hdr)); 836 837 ptr += len; 838 offset += len; 839 840 /* 841 * Put this fragment into the sending queue. 842 */ 843 err = output(net, sk, frag); 844 if (err) 845 goto fail; 846 847 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 848 IPSTATS_MIB_FRAGCREATES); 849 } 850 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 851 IPSTATS_MIB_FRAGOKS); 852 consume_skb(skb); 853 return err; 854 855 fail_toobig: 856 if (skb->sk && dst_allfrag(skb_dst(skb))) 857 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK); 858 859 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 860 err = -EMSGSIZE; 861 862 fail: 863 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 864 IPSTATS_MIB_FRAGFAILS); 865 kfree_skb(skb); 866 return err; 867 } 868 869 static inline int ip6_rt_check(const struct rt6key *rt_key, 870 const struct in6_addr *fl_addr, 871 const struct in6_addr *addr_cache) 872 { 873 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && 874 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache)); 875 } 876 877 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 878 struct dst_entry *dst, 879 const struct flowi6 *fl6) 880 { 881 struct ipv6_pinfo *np = inet6_sk(sk); 882 struct rt6_info *rt; 883 884 if (!dst) 885 goto out; 886 887 if (dst->ops->family != AF_INET6) { 888 dst_release(dst); 889 return NULL; 890 } 891 892 rt = (struct rt6_info *)dst; 893 /* Yes, checking route validity in not connected 894 * case is not very simple. Take into account, 895 * that we do not support routing by source, TOS, 896 * and MSG_DONTROUTE --ANK (980726) 897 * 898 * 1. ip6_rt_check(): If route was host route, 899 * check that cached destination is current. 900 * If it is network route, we still may 901 * check its validity using saved pointer 902 * to the last used address: daddr_cache. 903 * We do not want to save whole address now, 904 * (because main consumer of this service 905 * is tcp, which has not this problem), 906 * so that the last trick works only on connected 907 * sockets. 908 * 2. oif also should be the same. 909 */ 910 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) || 911 #ifdef CONFIG_IPV6_SUBTREES 912 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) || 913 #endif 914 (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) && 915 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) { 916 dst_release(dst); 917 dst = NULL; 918 } 919 920 out: 921 return dst; 922 } 923 924 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 925 struct dst_entry **dst, struct flowi6 *fl6) 926 { 927 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 928 struct neighbour *n; 929 struct rt6_info *rt; 930 #endif 931 int err; 932 int flags = 0; 933 934 /* The correct way to handle this would be to do 935 * ip6_route_get_saddr, and then ip6_route_output; however, 936 * the route-specific preferred source forces the 937 * ip6_route_output call _before_ ip6_route_get_saddr. 938 * 939 * In source specific routing (no src=any default route), 940 * ip6_route_output will fail given src=any saddr, though, so 941 * that's why we try it again later. 942 */ 943 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) { 944 struct fib6_info *from; 945 struct rt6_info *rt; 946 bool had_dst = *dst != NULL; 947 948 if (!had_dst) 949 *dst = ip6_route_output(net, sk, fl6); 950 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst; 951 952 rcu_read_lock(); 953 from = rt ? rcu_dereference(rt->from) : NULL; 954 err = ip6_route_get_saddr(net, from, &fl6->daddr, 955 sk ? inet6_sk(sk)->srcprefs : 0, 956 &fl6->saddr); 957 rcu_read_unlock(); 958 959 if (err) 960 goto out_err_release; 961 962 /* If we had an erroneous initial result, pretend it 963 * never existed and let the SA-enabled version take 964 * over. 965 */ 966 if (!had_dst && (*dst)->error) { 967 dst_release(*dst); 968 *dst = NULL; 969 } 970 971 if (fl6->flowi6_oif) 972 flags |= RT6_LOOKUP_F_IFACE; 973 } 974 975 if (!*dst) 976 *dst = ip6_route_output_flags(net, sk, fl6, flags); 977 978 err = (*dst)->error; 979 if (err) 980 goto out_err_release; 981 982 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD 983 /* 984 * Here if the dst entry we've looked up 985 * has a neighbour entry that is in the INCOMPLETE 986 * state and the src address from the flow is 987 * marked as OPTIMISTIC, we release the found 988 * dst entry and replace it instead with the 989 * dst entry of the nexthop router 990 */ 991 rt = (struct rt6_info *) *dst; 992 rcu_read_lock_bh(); 993 n = __ipv6_neigh_lookup_noref(rt->dst.dev, 994 rt6_nexthop(rt, &fl6->daddr)); 995 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; 996 rcu_read_unlock_bh(); 997 998 if (err) { 999 struct inet6_ifaddr *ifp; 1000 struct flowi6 fl_gw6; 1001 int redirect; 1002 1003 ifp = ipv6_get_ifaddr(net, &fl6->saddr, 1004 (*dst)->dev, 1); 1005 1006 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); 1007 if (ifp) 1008 in6_ifa_put(ifp); 1009 1010 if (redirect) { 1011 /* 1012 * We need to get the dst entry for the 1013 * default router instead 1014 */ 1015 dst_release(*dst); 1016 memcpy(&fl_gw6, fl6, sizeof(struct flowi6)); 1017 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr)); 1018 *dst = ip6_route_output(net, sk, &fl_gw6); 1019 err = (*dst)->error; 1020 if (err) 1021 goto out_err_release; 1022 } 1023 } 1024 #endif 1025 if (ipv6_addr_v4mapped(&fl6->saddr) && 1026 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) { 1027 err = -EAFNOSUPPORT; 1028 goto out_err_release; 1029 } 1030 1031 return 0; 1032 1033 out_err_release: 1034 dst_release(*dst); 1035 *dst = NULL; 1036 1037 if (err == -ENETUNREACH) 1038 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES); 1039 return err; 1040 } 1041 1042 /** 1043 * ip6_dst_lookup - perform route lookup on flow 1044 * @sk: socket which provides route info 1045 * @dst: pointer to dst_entry * for result 1046 * @fl6: flow to lookup 1047 * 1048 * This function performs a route lookup on the given flow. 1049 * 1050 * It returns zero on success, or a standard errno code on error. 1051 */ 1052 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst, 1053 struct flowi6 *fl6) 1054 { 1055 *dst = NULL; 1056 return ip6_dst_lookup_tail(net, sk, dst, fl6); 1057 } 1058 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 1059 1060 /** 1061 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec 1062 * @sk: socket which provides route info 1063 * @fl6: flow to lookup 1064 * @final_dst: final destination address for ipsec lookup 1065 * 1066 * This function performs a route lookup on the given flow. 1067 * 1068 * It returns a valid dst pointer on success, or a pointer encoded 1069 * error code. 1070 */ 1071 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6, 1072 const struct in6_addr *final_dst) 1073 { 1074 struct dst_entry *dst = NULL; 1075 int err; 1076 1077 err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6); 1078 if (err) 1079 return ERR_PTR(err); 1080 if (final_dst) 1081 fl6->daddr = *final_dst; 1082 1083 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); 1084 } 1085 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); 1086 1087 /** 1088 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow 1089 * @sk: socket which provides the dst cache and route info 1090 * @fl6: flow to lookup 1091 * @final_dst: final destination address for ipsec lookup 1092 * @connected: whether @sk is connected or not 1093 * 1094 * This function performs a route lookup on the given flow with the 1095 * possibility of using the cached route in the socket if it is valid. 1096 * It will take the socket dst lock when operating on the dst cache. 1097 * As a result, this function can only be used in process context. 1098 * 1099 * In addition, for a connected socket, cache the dst in the socket 1100 * if the current cache is not valid. 1101 * 1102 * It returns a valid dst pointer on success, or a pointer encoded 1103 * error code. 1104 */ 1105 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 1106 const struct in6_addr *final_dst, 1107 bool connected) 1108 { 1109 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 1110 1111 dst = ip6_sk_dst_check(sk, dst, fl6); 1112 if (dst) 1113 return dst; 1114 1115 dst = ip6_dst_lookup_flow(sk, fl6, final_dst); 1116 if (connected && !IS_ERR(dst)) 1117 ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6); 1118 1119 return dst; 1120 } 1121 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); 1122 1123 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src, 1124 gfp_t gfp) 1125 { 1126 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1127 } 1128 1129 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src, 1130 gfp_t gfp) 1131 { 1132 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL; 1133 } 1134 1135 static void ip6_append_data_mtu(unsigned int *mtu, 1136 int *maxfraglen, 1137 unsigned int fragheaderlen, 1138 struct sk_buff *skb, 1139 struct rt6_info *rt, 1140 unsigned int orig_mtu) 1141 { 1142 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) { 1143 if (!skb) { 1144 /* first fragment, reserve header_len */ 1145 *mtu = orig_mtu - rt->dst.header_len; 1146 1147 } else { 1148 /* 1149 * this fragment is not first, the headers 1150 * space is regarded as data space. 1151 */ 1152 *mtu = orig_mtu; 1153 } 1154 *maxfraglen = ((*mtu - fragheaderlen) & ~7) 1155 + fragheaderlen - sizeof(struct frag_hdr); 1156 } 1157 } 1158 1159 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 1160 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6, 1161 struct rt6_info *rt, struct flowi6 *fl6) 1162 { 1163 struct ipv6_pinfo *np = inet6_sk(sk); 1164 unsigned int mtu; 1165 struct ipv6_txoptions *opt = ipc6->opt; 1166 1167 /* 1168 * setup for corking 1169 */ 1170 if (opt) { 1171 if (WARN_ON(v6_cork->opt)) 1172 return -EINVAL; 1173 1174 v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation); 1175 if (unlikely(!v6_cork->opt)) 1176 return -ENOBUFS; 1177 1178 v6_cork->opt->tot_len = sizeof(*opt); 1179 v6_cork->opt->opt_flen = opt->opt_flen; 1180 v6_cork->opt->opt_nflen = opt->opt_nflen; 1181 1182 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt, 1183 sk->sk_allocation); 1184 if (opt->dst0opt && !v6_cork->opt->dst0opt) 1185 return -ENOBUFS; 1186 1187 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt, 1188 sk->sk_allocation); 1189 if (opt->dst1opt && !v6_cork->opt->dst1opt) 1190 return -ENOBUFS; 1191 1192 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt, 1193 sk->sk_allocation); 1194 if (opt->hopopt && !v6_cork->opt->hopopt) 1195 return -ENOBUFS; 1196 1197 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt, 1198 sk->sk_allocation); 1199 if (opt->srcrt && !v6_cork->opt->srcrt) 1200 return -ENOBUFS; 1201 1202 /* need source address above miyazawa*/ 1203 } 1204 dst_hold(&rt->dst); 1205 cork->base.dst = &rt->dst; 1206 cork->fl.u.ip6 = *fl6; 1207 v6_cork->hop_limit = ipc6->hlimit; 1208 v6_cork->tclass = ipc6->tclass; 1209 if (rt->dst.flags & DST_XFRM_TUNNEL) 1210 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1211 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst); 1212 else 1213 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? 1214 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst)); 1215 if (np->frag_size < mtu) { 1216 if (np->frag_size) 1217 mtu = np->frag_size; 1218 } 1219 if (mtu < IPV6_MIN_MTU) 1220 return -EINVAL; 1221 cork->base.fragsize = mtu; 1222 cork->base.gso_size = sk->sk_type == SOCK_DGRAM && 1223 sk->sk_protocol == IPPROTO_UDP ? ipc6->gso_size : 0; 1224 1225 if (dst_allfrag(xfrm_dst_path(&rt->dst))) 1226 cork->base.flags |= IPCORK_ALLFRAG; 1227 cork->base.length = 0; 1228 1229 cork->base.transmit_time = ipc6->sockc.transmit_time; 1230 1231 return 0; 1232 } 1233 1234 static int __ip6_append_data(struct sock *sk, 1235 struct flowi6 *fl6, 1236 struct sk_buff_head *queue, 1237 struct inet_cork *cork, 1238 struct inet6_cork *v6_cork, 1239 struct page_frag *pfrag, 1240 int getfrag(void *from, char *to, int offset, 1241 int len, int odd, struct sk_buff *skb), 1242 void *from, int length, int transhdrlen, 1243 unsigned int flags, struct ipcm6_cookie *ipc6) 1244 { 1245 struct sk_buff *skb, *skb_prev = NULL; 1246 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; 1247 int exthdrlen = 0; 1248 int dst_exthdrlen = 0; 1249 int hh_len; 1250 int copy; 1251 int err; 1252 int offset = 0; 1253 __u8 tx_flags = 0; 1254 u32 tskey = 0; 1255 struct rt6_info *rt = (struct rt6_info *)cork->dst; 1256 struct ipv6_txoptions *opt = v6_cork->opt; 1257 int csummode = CHECKSUM_NONE; 1258 unsigned int maxnonfragsize, headersize; 1259 unsigned int wmem_alloc_delta = 0; 1260 bool paged; 1261 1262 skb = skb_peek_tail(queue); 1263 if (!skb) { 1264 exthdrlen = opt ? opt->opt_flen : 0; 1265 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len; 1266 } 1267 1268 paged = !!cork->gso_size; 1269 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize; 1270 orig_mtu = mtu; 1271 1272 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1273 1274 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1275 (opt ? opt->opt_nflen : 0); 1276 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1277 sizeof(struct frag_hdr); 1278 1279 headersize = sizeof(struct ipv6hdr) + 1280 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1281 (dst_allfrag(&rt->dst) ? 1282 sizeof(struct frag_hdr) : 0) + 1283 rt->rt6i_nfheader_len; 1284 1285 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit 1286 * the first fragment 1287 */ 1288 if (headersize + transhdrlen > mtu) 1289 goto emsgsize; 1290 1291 if (cork->length + length > mtu - headersize && ipc6->dontfrag && 1292 (sk->sk_protocol == IPPROTO_UDP || 1293 sk->sk_protocol == IPPROTO_RAW)) { 1294 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1295 sizeof(struct ipv6hdr)); 1296 goto emsgsize; 1297 } 1298 1299 if (ip6_sk_ignore_df(sk)) 1300 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1301 else 1302 maxnonfragsize = mtu; 1303 1304 if (cork->length + length > maxnonfragsize - headersize) { 1305 emsgsize: 1306 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); 1307 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); 1308 return -EMSGSIZE; 1309 } 1310 1311 /* CHECKSUM_PARTIAL only with no extension headers and when 1312 * we are not going to fragment 1313 */ 1314 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1315 headersize == sizeof(struct ipv6hdr) && 1316 length <= mtu - headersize && 1317 (!(flags & MSG_MORE) || cork->gso_size) && 1318 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM)) 1319 csummode = CHECKSUM_PARTIAL; 1320 1321 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) { 1322 sock_tx_timestamp(sk, ipc6->sockc.tsflags, &tx_flags); 1323 if (tx_flags & SKBTX_ANY_SW_TSTAMP && 1324 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1325 tskey = sk->sk_tskey++; 1326 } 1327 1328 /* 1329 * Let's try using as much space as possible. 1330 * Use MTU if total length of the message fits into the MTU. 1331 * Otherwise, we need to reserve fragment header and 1332 * fragment alignment (= 8-15 octects, in total). 1333 * 1334 * Note that we may need to "move" the data from the tail of 1335 * of the buffer to the new fragment when we split 1336 * the message. 1337 * 1338 * FIXME: It may be fragmented into multiple chunks 1339 * at once if non-fragmentable extension headers 1340 * are too large. 1341 * --yoshfuji 1342 */ 1343 1344 cork->length += length; 1345 if (!skb) 1346 goto alloc_new_skb; 1347 1348 while (length > 0) { 1349 /* Check if the remaining data fits into current packet. */ 1350 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1351 if (copy < length) 1352 copy = maxfraglen - skb->len; 1353 1354 if (copy <= 0) { 1355 char *data; 1356 unsigned int datalen; 1357 unsigned int fraglen; 1358 unsigned int fraggap; 1359 unsigned int alloclen; 1360 unsigned int pagedlen = 0; 1361 alloc_new_skb: 1362 /* There's no room in the current skb */ 1363 if (skb) 1364 fraggap = skb->len - maxfraglen; 1365 else 1366 fraggap = 0; 1367 /* update mtu and maxfraglen if necessary */ 1368 if (!skb || !skb_prev) 1369 ip6_append_data_mtu(&mtu, &maxfraglen, 1370 fragheaderlen, skb, rt, 1371 orig_mtu); 1372 1373 skb_prev = skb; 1374 1375 /* 1376 * If remaining data exceeds the mtu, 1377 * we know we need more fragment(s). 1378 */ 1379 datalen = length + fraggap; 1380 1381 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1382 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1383 fraglen = datalen + fragheaderlen; 1384 1385 if ((flags & MSG_MORE) && 1386 !(rt->dst.dev->features&NETIF_F_SG)) 1387 alloclen = mtu; 1388 else if (!paged) 1389 alloclen = fraglen; 1390 else { 1391 alloclen = min_t(int, fraglen, MAX_HEADER); 1392 pagedlen = fraglen - alloclen; 1393 } 1394 1395 alloclen += dst_exthdrlen; 1396 1397 if (datalen != length + fraggap) { 1398 /* 1399 * this is not the last fragment, the trailer 1400 * space is regarded as data space. 1401 */ 1402 datalen += rt->dst.trailer_len; 1403 } 1404 1405 alloclen += rt->dst.trailer_len; 1406 fraglen = datalen + fragheaderlen; 1407 1408 /* 1409 * We just reserve space for fragment header. 1410 * Note: this may be overallocation if the message 1411 * (without MSG_MORE) fits into the MTU. 1412 */ 1413 alloclen += sizeof(struct frag_hdr); 1414 1415 copy = datalen - transhdrlen - fraggap - pagedlen; 1416 if (copy < 0) { 1417 err = -EINVAL; 1418 goto error; 1419 } 1420 if (transhdrlen) { 1421 skb = sock_alloc_send_skb(sk, 1422 alloclen + hh_len, 1423 (flags & MSG_DONTWAIT), &err); 1424 } else { 1425 skb = NULL; 1426 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 1427 2 * sk->sk_sndbuf) 1428 skb = alloc_skb(alloclen + hh_len, 1429 sk->sk_allocation); 1430 if (unlikely(!skb)) 1431 err = -ENOBUFS; 1432 } 1433 if (!skb) 1434 goto error; 1435 /* 1436 * Fill in the control structures 1437 */ 1438 skb->protocol = htons(ETH_P_IPV6); 1439 skb->ip_summed = csummode; 1440 skb->csum = 0; 1441 /* reserve for fragmentation and ipsec header */ 1442 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1443 dst_exthdrlen); 1444 1445 /* Only the initial fragment is time stamped */ 1446 skb_shinfo(skb)->tx_flags = tx_flags; 1447 tx_flags = 0; 1448 skb_shinfo(skb)->tskey = tskey; 1449 tskey = 0; 1450 1451 /* 1452 * Find where to start putting bytes 1453 */ 1454 data = skb_put(skb, fraglen - pagedlen); 1455 skb_set_network_header(skb, exthdrlen); 1456 data += fragheaderlen; 1457 skb->transport_header = (skb->network_header + 1458 fragheaderlen); 1459 if (fraggap) { 1460 skb->csum = skb_copy_and_csum_bits( 1461 skb_prev, maxfraglen, 1462 data + transhdrlen, fraggap, 0); 1463 skb_prev->csum = csum_sub(skb_prev->csum, 1464 skb->csum); 1465 data += fraggap; 1466 pskb_trim_unique(skb_prev, maxfraglen); 1467 } 1468 if (copy > 0 && 1469 getfrag(from, data + transhdrlen, offset, 1470 copy, fraggap, skb) < 0) { 1471 err = -EFAULT; 1472 kfree_skb(skb); 1473 goto error; 1474 } 1475 1476 offset += copy; 1477 length -= copy + transhdrlen; 1478 transhdrlen = 0; 1479 exthdrlen = 0; 1480 dst_exthdrlen = 0; 1481 1482 if ((flags & MSG_CONFIRM) && !skb_prev) 1483 skb_set_dst_pending_confirm(skb, 1); 1484 1485 /* 1486 * Put the packet on the pending queue 1487 */ 1488 if (!skb->destructor) { 1489 skb->destructor = sock_wfree; 1490 skb->sk = sk; 1491 wmem_alloc_delta += skb->truesize; 1492 } 1493 __skb_queue_tail(queue, skb); 1494 continue; 1495 } 1496 1497 if (copy > length) 1498 copy = length; 1499 1500 if (!(rt->dst.dev->features&NETIF_F_SG) && 1501 skb_tailroom(skb) >= copy) { 1502 unsigned int off; 1503 1504 off = skb->len; 1505 if (getfrag(from, skb_put(skb, copy), 1506 offset, copy, off, skb) < 0) { 1507 __skb_trim(skb, off); 1508 err = -EFAULT; 1509 goto error; 1510 } 1511 } else { 1512 int i = skb_shinfo(skb)->nr_frags; 1513 1514 err = -ENOMEM; 1515 if (!sk_page_frag_refill(sk, pfrag)) 1516 goto error; 1517 1518 if (!skb_can_coalesce(skb, i, pfrag->page, 1519 pfrag->offset)) { 1520 err = -EMSGSIZE; 1521 if (i == MAX_SKB_FRAGS) 1522 goto error; 1523 1524 __skb_fill_page_desc(skb, i, pfrag->page, 1525 pfrag->offset, 0); 1526 skb_shinfo(skb)->nr_frags = ++i; 1527 get_page(pfrag->page); 1528 } 1529 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1530 if (getfrag(from, 1531 page_address(pfrag->page) + pfrag->offset, 1532 offset, copy, skb->len, skb) < 0) 1533 goto error_efault; 1534 1535 pfrag->offset += copy; 1536 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1537 skb->len += copy; 1538 skb->data_len += copy; 1539 skb->truesize += copy; 1540 wmem_alloc_delta += copy; 1541 } 1542 offset += copy; 1543 length -= copy; 1544 } 1545 1546 if (wmem_alloc_delta) 1547 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1548 return 0; 1549 1550 error_efault: 1551 err = -EFAULT; 1552 error: 1553 cork->length -= length; 1554 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1555 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1556 return err; 1557 } 1558 1559 int ip6_append_data(struct sock *sk, 1560 int getfrag(void *from, char *to, int offset, int len, 1561 int odd, struct sk_buff *skb), 1562 void *from, int length, int transhdrlen, 1563 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1564 struct rt6_info *rt, unsigned int flags) 1565 { 1566 struct inet_sock *inet = inet_sk(sk); 1567 struct ipv6_pinfo *np = inet6_sk(sk); 1568 int exthdrlen; 1569 int err; 1570 1571 if (flags&MSG_PROBE) 1572 return 0; 1573 if (skb_queue_empty(&sk->sk_write_queue)) { 1574 /* 1575 * setup for corking 1576 */ 1577 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1578 ipc6, rt, fl6); 1579 if (err) 1580 return err; 1581 1582 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1583 length += exthdrlen; 1584 transhdrlen += exthdrlen; 1585 } else { 1586 fl6 = &inet->cork.fl.u.ip6; 1587 transhdrlen = 0; 1588 } 1589 1590 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1591 &np->cork, sk_page_frag(sk), getfrag, 1592 from, length, transhdrlen, flags, ipc6); 1593 } 1594 EXPORT_SYMBOL_GPL(ip6_append_data); 1595 1596 static void ip6_cork_release(struct inet_cork_full *cork, 1597 struct inet6_cork *v6_cork) 1598 { 1599 if (v6_cork->opt) { 1600 kfree(v6_cork->opt->dst0opt); 1601 kfree(v6_cork->opt->dst1opt); 1602 kfree(v6_cork->opt->hopopt); 1603 kfree(v6_cork->opt->srcrt); 1604 kfree(v6_cork->opt); 1605 v6_cork->opt = NULL; 1606 } 1607 1608 if (cork->base.dst) { 1609 dst_release(cork->base.dst); 1610 cork->base.dst = NULL; 1611 cork->base.flags &= ~IPCORK_ALLFRAG; 1612 } 1613 memset(&cork->fl, 0, sizeof(cork->fl)); 1614 } 1615 1616 struct sk_buff *__ip6_make_skb(struct sock *sk, 1617 struct sk_buff_head *queue, 1618 struct inet_cork_full *cork, 1619 struct inet6_cork *v6_cork) 1620 { 1621 struct sk_buff *skb, *tmp_skb; 1622 struct sk_buff **tail_skb; 1623 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1624 struct ipv6_pinfo *np = inet6_sk(sk); 1625 struct net *net = sock_net(sk); 1626 struct ipv6hdr *hdr; 1627 struct ipv6_txoptions *opt = v6_cork->opt; 1628 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1629 struct flowi6 *fl6 = &cork->fl.u.ip6; 1630 unsigned char proto = fl6->flowi6_proto; 1631 1632 skb = __skb_dequeue(queue); 1633 if (!skb) 1634 goto out; 1635 tail_skb = &(skb_shinfo(skb)->frag_list); 1636 1637 /* move skb->data to ip header from ext header */ 1638 if (skb->data < skb_network_header(skb)) 1639 __skb_pull(skb, skb_network_offset(skb)); 1640 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1641 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1642 *tail_skb = tmp_skb; 1643 tail_skb = &(tmp_skb->next); 1644 skb->len += tmp_skb->len; 1645 skb->data_len += tmp_skb->len; 1646 skb->truesize += tmp_skb->truesize; 1647 tmp_skb->destructor = NULL; 1648 tmp_skb->sk = NULL; 1649 } 1650 1651 /* Allow local fragmentation. */ 1652 skb->ignore_df = ip6_sk_ignore_df(sk); 1653 1654 *final_dst = fl6->daddr; 1655 __skb_pull(skb, skb_network_header_len(skb)); 1656 if (opt && opt->opt_flen) 1657 ipv6_push_frag_opts(skb, opt, &proto); 1658 if (opt && opt->opt_nflen) 1659 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1660 1661 skb_push(skb, sizeof(struct ipv6hdr)); 1662 skb_reset_network_header(skb); 1663 hdr = ipv6_hdr(skb); 1664 1665 ip6_flow_hdr(hdr, v6_cork->tclass, 1666 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1667 ip6_autoflowlabel(net, np), fl6)); 1668 hdr->hop_limit = v6_cork->hop_limit; 1669 hdr->nexthdr = proto; 1670 hdr->saddr = fl6->saddr; 1671 hdr->daddr = *final_dst; 1672 1673 skb->priority = sk->sk_priority; 1674 skb->mark = sk->sk_mark; 1675 1676 skb->tstamp = cork->base.transmit_time; 1677 1678 skb_dst_set(skb, dst_clone(&rt->dst)); 1679 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1680 if (proto == IPPROTO_ICMPV6) { 1681 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1682 1683 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1684 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1685 } 1686 1687 ip6_cork_release(cork, v6_cork); 1688 out: 1689 return skb; 1690 } 1691 1692 int ip6_send_skb(struct sk_buff *skb) 1693 { 1694 struct net *net = sock_net(skb->sk); 1695 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1696 int err; 1697 1698 err = ip6_local_out(net, skb->sk, skb); 1699 if (err) { 1700 if (err > 0) 1701 err = net_xmit_errno(err); 1702 if (err) 1703 IP6_INC_STATS(net, rt->rt6i_idev, 1704 IPSTATS_MIB_OUTDISCARDS); 1705 } 1706 1707 return err; 1708 } 1709 1710 int ip6_push_pending_frames(struct sock *sk) 1711 { 1712 struct sk_buff *skb; 1713 1714 skb = ip6_finish_skb(sk); 1715 if (!skb) 1716 return 0; 1717 1718 return ip6_send_skb(skb); 1719 } 1720 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1721 1722 static void __ip6_flush_pending_frames(struct sock *sk, 1723 struct sk_buff_head *queue, 1724 struct inet_cork_full *cork, 1725 struct inet6_cork *v6_cork) 1726 { 1727 struct sk_buff *skb; 1728 1729 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1730 if (skb_dst(skb)) 1731 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1732 IPSTATS_MIB_OUTDISCARDS); 1733 kfree_skb(skb); 1734 } 1735 1736 ip6_cork_release(cork, v6_cork); 1737 } 1738 1739 void ip6_flush_pending_frames(struct sock *sk) 1740 { 1741 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1742 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1743 } 1744 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1745 1746 struct sk_buff *ip6_make_skb(struct sock *sk, 1747 int getfrag(void *from, char *to, int offset, 1748 int len, int odd, struct sk_buff *skb), 1749 void *from, int length, int transhdrlen, 1750 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1751 struct rt6_info *rt, unsigned int flags, 1752 struct inet_cork_full *cork) 1753 { 1754 struct inet6_cork v6_cork; 1755 struct sk_buff_head queue; 1756 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1757 int err; 1758 1759 if (flags & MSG_PROBE) 1760 return NULL; 1761 1762 __skb_queue_head_init(&queue); 1763 1764 cork->base.flags = 0; 1765 cork->base.addr = 0; 1766 cork->base.opt = NULL; 1767 cork->base.dst = NULL; 1768 v6_cork.opt = NULL; 1769 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6); 1770 if (err) { 1771 ip6_cork_release(cork, &v6_cork); 1772 return ERR_PTR(err); 1773 } 1774 if (ipc6->dontfrag < 0) 1775 ipc6->dontfrag = inet6_sk(sk)->dontfrag; 1776 1777 err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork, 1778 ¤t->task_frag, getfrag, from, 1779 length + exthdrlen, transhdrlen + exthdrlen, 1780 flags, ipc6); 1781 if (err) { 1782 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); 1783 return ERR_PTR(err); 1784 } 1785 1786 return __ip6_make_skb(sk, &queue, cork, &v6_cork); 1787 } 1788