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 if (skb->sk) 223 skb_set_owner_w(skb2, skb->sk); 224 consume_skb(skb); 225 skb = skb2; 226 } 227 if (opt->opt_flen) 228 ipv6_push_frag_opts(skb, opt, &proto); 229 if (opt->opt_nflen) 230 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop, 231 &fl6->saddr); 232 } 233 234 skb_push(skb, sizeof(struct ipv6hdr)); 235 skb_reset_network_header(skb); 236 hdr = ipv6_hdr(skb); 237 238 /* 239 * Fill in the IPv6 header 240 */ 241 if (np) 242 hlimit = np->hop_limit; 243 if (hlimit < 0) 244 hlimit = ip6_dst_hoplimit(dst); 245 246 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel, 247 ip6_autoflowlabel(net, np), fl6)); 248 249 hdr->payload_len = htons(seg_len); 250 hdr->nexthdr = proto; 251 hdr->hop_limit = hlimit; 252 253 hdr->saddr = fl6->saddr; 254 hdr->daddr = *first_hop; 255 256 skb->protocol = htons(ETH_P_IPV6); 257 skb->priority = sk->sk_priority; 258 skb->mark = mark; 259 260 mtu = dst_mtu(dst); 261 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) { 262 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)), 263 IPSTATS_MIB_OUT, skb->len); 264 265 /* if egress device is enslaved to an L3 master device pass the 266 * skb to its handler for processing 267 */ 268 skb = l3mdev_ip6_out((struct sock *)sk, skb); 269 if (unlikely(!skb)) 270 return 0; 271 272 /* hooks should never assume socket lock is held. 273 * we promote our socket to non const 274 */ 275 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 276 net, (struct sock *)sk, skb, NULL, dst->dev, 277 dst_output); 278 } 279 280 skb->dev = dst->dev; 281 /* ipv6_local_error() does not require socket lock, 282 * we promote our socket to non const 283 */ 284 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu); 285 286 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS); 287 kfree_skb(skb); 288 return -EMSGSIZE; 289 } 290 EXPORT_SYMBOL(ip6_xmit); 291 292 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 293 { 294 struct ip6_ra_chain *ra; 295 struct sock *last = NULL; 296 297 read_lock(&ip6_ra_lock); 298 for (ra = ip6_ra_chain; ra; ra = ra->next) { 299 struct sock *sk = ra->sk; 300 if (sk && ra->sel == sel && 301 (!sk->sk_bound_dev_if || 302 sk->sk_bound_dev_if == skb->dev->ifindex)) { 303 if (last) { 304 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 305 if (skb2) 306 rawv6_rcv(last, skb2); 307 } 308 last = sk; 309 } 310 } 311 312 if (last) { 313 rawv6_rcv(last, skb); 314 read_unlock(&ip6_ra_lock); 315 return 1; 316 } 317 read_unlock(&ip6_ra_lock); 318 return 0; 319 } 320 321 static int ip6_forward_proxy_check(struct sk_buff *skb) 322 { 323 struct ipv6hdr *hdr = ipv6_hdr(skb); 324 u8 nexthdr = hdr->nexthdr; 325 __be16 frag_off; 326 int offset; 327 328 if (ipv6_ext_hdr(nexthdr)) { 329 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off); 330 if (offset < 0) 331 return 0; 332 } else 333 offset = sizeof(struct ipv6hdr); 334 335 if (nexthdr == IPPROTO_ICMPV6) { 336 struct icmp6hdr *icmp6; 337 338 if (!pskb_may_pull(skb, (skb_network_header(skb) + 339 offset + 1 - skb->data))) 340 return 0; 341 342 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 343 344 switch (icmp6->icmp6_type) { 345 case NDISC_ROUTER_SOLICITATION: 346 case NDISC_ROUTER_ADVERTISEMENT: 347 case NDISC_NEIGHBOUR_SOLICITATION: 348 case NDISC_NEIGHBOUR_ADVERTISEMENT: 349 case NDISC_REDIRECT: 350 /* For reaction involving unicast neighbor discovery 351 * message destined to the proxied address, pass it to 352 * input function. 353 */ 354 return 1; 355 default: 356 break; 357 } 358 } 359 360 /* 361 * The proxying router can't forward traffic sent to a link-local 362 * address, so signal the sender and discard the packet. This 363 * behavior is clarified by the MIPv6 specification. 364 */ 365 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { 366 dst_link_failure(skb); 367 return -1; 368 } 369 370 return 0; 371 } 372 373 static inline int ip6_forward_finish(struct net *net, struct sock *sk, 374 struct sk_buff *skb) 375 { 376 struct dst_entry *dst = skb_dst(skb); 377 378 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); 379 __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len); 380 381 return dst_output(net, sk, skb); 382 } 383 384 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) 385 { 386 if (skb->len <= mtu) 387 return false; 388 389 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */ 390 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) 391 return true; 392 393 if (skb->ignore_df) 394 return false; 395 396 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu)) 397 return false; 398 399 return true; 400 } 401 402 int ip6_forward(struct sk_buff *skb) 403 { 404 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev); 405 struct dst_entry *dst = skb_dst(skb); 406 struct ipv6hdr *hdr = ipv6_hdr(skb); 407 struct inet6_skb_parm *opt = IP6CB(skb); 408 struct net *net = dev_net(dst->dev); 409 u32 mtu; 410 411 if (net->ipv6.devconf_all->forwarding == 0) 412 goto error; 413 414 if (skb->pkt_type != PACKET_HOST) 415 goto drop; 416 417 if (unlikely(skb->sk)) 418 goto drop; 419 420 if (skb_warn_if_lro(skb)) 421 goto drop; 422 423 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 424 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 425 goto drop; 426 } 427 428 skb_forward_csum(skb); 429 430 /* 431 * We DO NOT make any processing on 432 * RA packets, pushing them to user level AS IS 433 * without ane WARRANTY that application will be able 434 * to interpret them. The reason is that we 435 * cannot make anything clever here. 436 * 437 * We are not end-node, so that if packet contains 438 * AH/ESP, we cannot make anything. 439 * Defragmentation also would be mistake, RA packets 440 * cannot be fragmented, because there is no warranty 441 * that different fragments will go along one path. --ANK 442 */ 443 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { 444 if (ip6_call_ra_chain(skb, ntohs(opt->ra))) 445 return 0; 446 } 447 448 /* 449 * check and decrement ttl 450 */ 451 if (hdr->hop_limit <= 1) { 452 /* Force OUTPUT device used as source address */ 453 skb->dev = dst->dev; 454 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); 455 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 456 457 kfree_skb(skb); 458 return -ETIMEDOUT; 459 } 460 461 /* XXX: idev->cnf.proxy_ndp? */ 462 if (net->ipv6.devconf_all->proxy_ndp && 463 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) { 464 int proxied = ip6_forward_proxy_check(skb); 465 if (proxied > 0) 466 return ip6_input(skb); 467 else if (proxied < 0) { 468 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 469 goto drop; 470 } 471 } 472 473 if (!xfrm6_route_forward(skb)) { 474 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); 475 goto drop; 476 } 477 dst = skb_dst(skb); 478 479 /* IPv6 specs say nothing about it, but it is clear that we cannot 480 send redirects to source routed frames. 481 We don't send redirects to frames decapsulated from IPsec. 482 */ 483 if (IP6CB(skb)->iif == dst->dev->ifindex && 484 opt->srcrt == 0 && !skb_sec_path(skb)) { 485 struct in6_addr *target = NULL; 486 struct inet_peer *peer; 487 struct rt6_info *rt; 488 489 /* 490 * incoming and outgoing devices are the same 491 * send a redirect. 492 */ 493 494 rt = (struct rt6_info *) dst; 495 if (rt->rt6i_flags & RTF_GATEWAY) 496 target = &rt->rt6i_gateway; 497 else 498 target = &hdr->daddr; 499 500 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1); 501 502 /* Limit redirects both by destination (here) 503 and by source (inside ndisc_send_redirect) 504 */ 505 if (inet_peer_xrlim_allow(peer, 1*HZ)) 506 ndisc_send_redirect(skb, target); 507 if (peer) 508 inet_putpeer(peer); 509 } else { 510 int addrtype = ipv6_addr_type(&hdr->saddr); 511 512 /* This check is security critical. */ 513 if (addrtype == IPV6_ADDR_ANY || 514 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK)) 515 goto error; 516 if (addrtype & IPV6_ADDR_LINKLOCAL) { 517 icmpv6_send(skb, ICMPV6_DEST_UNREACH, 518 ICMPV6_NOT_NEIGHBOUR, 0); 519 goto error; 520 } 521 } 522 523 mtu = ip6_dst_mtu_forward(dst); 524 if (mtu < IPV6_MIN_MTU) 525 mtu = IPV6_MIN_MTU; 526 527 if (ip6_pkt_too_big(skb, mtu)) { 528 /* Again, force OUTPUT device used as source address */ 529 skb->dev = dst->dev; 530 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 531 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS); 532 __IP6_INC_STATS(net, ip6_dst_idev(dst), 533 IPSTATS_MIB_FRAGFAILS); 534 kfree_skb(skb); 535 return -EMSGSIZE; 536 } 537 538 if (skb_cow(skb, dst->dev->hard_header_len)) { 539 __IP6_INC_STATS(net, ip6_dst_idev(dst), 540 IPSTATS_MIB_OUTDISCARDS); 541 goto drop; 542 } 543 544 hdr = ipv6_hdr(skb); 545 546 /* Mangling hops number delayed to point after skb COW */ 547 548 hdr->hop_limit--; 549 550 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, 551 net, NULL, skb, skb->dev, dst->dev, 552 ip6_forward_finish); 553 554 error: 555 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 556 drop: 557 kfree_skb(skb); 558 return -EINVAL; 559 } 560 561 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 562 { 563 to->pkt_type = from->pkt_type; 564 to->priority = from->priority; 565 to->protocol = from->protocol; 566 skb_dst_drop(to); 567 skb_dst_set(to, dst_clone(skb_dst(from))); 568 to->dev = from->dev; 569 to->mark = from->mark; 570 571 skb_copy_hash(to, from); 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_mark_not_on_list(skb); 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 = ipc6->gso_size; 1223 cork->base.tx_flags = 0; 1224 sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags); 1225 1226 if (dst_allfrag(xfrm_dst_path(&rt->dst))) 1227 cork->base.flags |= IPCORK_ALLFRAG; 1228 cork->base.length = 0; 1229 1230 cork->base.transmit_time = ipc6->sockc.transmit_time; 1231 1232 return 0; 1233 } 1234 1235 static int __ip6_append_data(struct sock *sk, 1236 struct flowi6 *fl6, 1237 struct sk_buff_head *queue, 1238 struct inet_cork *cork, 1239 struct inet6_cork *v6_cork, 1240 struct page_frag *pfrag, 1241 int getfrag(void *from, char *to, int offset, 1242 int len, int odd, struct sk_buff *skb), 1243 void *from, int length, int transhdrlen, 1244 unsigned int flags, struct ipcm6_cookie *ipc6) 1245 { 1246 struct sk_buff *skb, *skb_prev = NULL; 1247 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; 1248 int exthdrlen = 0; 1249 int dst_exthdrlen = 0; 1250 int hh_len; 1251 int copy; 1252 int err; 1253 int offset = 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 if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP && 1273 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) 1274 tskey = sk->sk_tskey++; 1275 1276 hh_len = LL_RESERVED_SPACE(rt->dst.dev); 1277 1278 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + 1279 (opt ? opt->opt_nflen : 0); 1280 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - 1281 sizeof(struct frag_hdr); 1282 1283 headersize = sizeof(struct ipv6hdr) + 1284 (opt ? opt->opt_flen + opt->opt_nflen : 0) + 1285 (dst_allfrag(&rt->dst) ? 1286 sizeof(struct frag_hdr) : 0) + 1287 rt->rt6i_nfheader_len; 1288 1289 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit 1290 * the first fragment 1291 */ 1292 if (headersize + transhdrlen > mtu) 1293 goto emsgsize; 1294 1295 if (cork->length + length > mtu - headersize && ipc6->dontfrag && 1296 (sk->sk_protocol == IPPROTO_UDP || 1297 sk->sk_protocol == IPPROTO_RAW)) { 1298 ipv6_local_rxpmtu(sk, fl6, mtu - headersize + 1299 sizeof(struct ipv6hdr)); 1300 goto emsgsize; 1301 } 1302 1303 if (ip6_sk_ignore_df(sk)) 1304 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN; 1305 else 1306 maxnonfragsize = mtu; 1307 1308 if (cork->length + length > maxnonfragsize - headersize) { 1309 emsgsize: 1310 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); 1311 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); 1312 return -EMSGSIZE; 1313 } 1314 1315 /* CHECKSUM_PARTIAL only with no extension headers and when 1316 * we are not going to fragment 1317 */ 1318 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP && 1319 headersize == sizeof(struct ipv6hdr) && 1320 length <= mtu - headersize && 1321 (!(flags & MSG_MORE) || cork->gso_size) && 1322 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM)) 1323 csummode = CHECKSUM_PARTIAL; 1324 1325 /* 1326 * Let's try using as much space as possible. 1327 * Use MTU if total length of the message fits into the MTU. 1328 * Otherwise, we need to reserve fragment header and 1329 * fragment alignment (= 8-15 octects, in total). 1330 * 1331 * Note that we may need to "move" the data from the tail of 1332 * of the buffer to the new fragment when we split 1333 * the message. 1334 * 1335 * FIXME: It may be fragmented into multiple chunks 1336 * at once if non-fragmentable extension headers 1337 * are too large. 1338 * --yoshfuji 1339 */ 1340 1341 cork->length += length; 1342 if (!skb) 1343 goto alloc_new_skb; 1344 1345 while (length > 0) { 1346 /* Check if the remaining data fits into current packet. */ 1347 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1348 if (copy < length) 1349 copy = maxfraglen - skb->len; 1350 1351 if (copy <= 0) { 1352 char *data; 1353 unsigned int datalen; 1354 unsigned int fraglen; 1355 unsigned int fraggap; 1356 unsigned int alloclen; 1357 unsigned int pagedlen; 1358 alloc_new_skb: 1359 /* There's no room in the current skb */ 1360 if (skb) 1361 fraggap = skb->len - maxfraglen; 1362 else 1363 fraggap = 0; 1364 /* update mtu and maxfraglen if necessary */ 1365 if (!skb || !skb_prev) 1366 ip6_append_data_mtu(&mtu, &maxfraglen, 1367 fragheaderlen, skb, rt, 1368 orig_mtu); 1369 1370 skb_prev = skb; 1371 1372 /* 1373 * If remaining data exceeds the mtu, 1374 * we know we need more fragment(s). 1375 */ 1376 datalen = length + fraggap; 1377 1378 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1379 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; 1380 fraglen = datalen + fragheaderlen; 1381 pagedlen = 0; 1382 1383 if ((flags & MSG_MORE) && 1384 !(rt->dst.dev->features&NETIF_F_SG)) 1385 alloclen = mtu; 1386 else if (!paged) 1387 alloclen = fraglen; 1388 else { 1389 alloclen = min_t(int, fraglen, MAX_HEADER); 1390 pagedlen = fraglen - alloclen; 1391 } 1392 1393 alloclen += dst_exthdrlen; 1394 1395 if (datalen != length + fraggap) { 1396 /* 1397 * this is not the last fragment, the trailer 1398 * space is regarded as data space. 1399 */ 1400 datalen += rt->dst.trailer_len; 1401 } 1402 1403 alloclen += rt->dst.trailer_len; 1404 fraglen = datalen + fragheaderlen; 1405 1406 /* 1407 * We just reserve space for fragment header. 1408 * Note: this may be overallocation if the message 1409 * (without MSG_MORE) fits into the MTU. 1410 */ 1411 alloclen += sizeof(struct frag_hdr); 1412 1413 copy = datalen - transhdrlen - fraggap - pagedlen; 1414 if (copy < 0) { 1415 err = -EINVAL; 1416 goto error; 1417 } 1418 if (transhdrlen) { 1419 skb = sock_alloc_send_skb(sk, 1420 alloclen + hh_len, 1421 (flags & MSG_DONTWAIT), &err); 1422 } else { 1423 skb = NULL; 1424 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 1425 2 * sk->sk_sndbuf) 1426 skb = alloc_skb(alloclen + hh_len, 1427 sk->sk_allocation); 1428 if (unlikely(!skb)) 1429 err = -ENOBUFS; 1430 } 1431 if (!skb) 1432 goto error; 1433 /* 1434 * Fill in the control structures 1435 */ 1436 skb->protocol = htons(ETH_P_IPV6); 1437 skb->ip_summed = csummode; 1438 skb->csum = 0; 1439 /* reserve for fragmentation and ipsec header */ 1440 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1441 dst_exthdrlen); 1442 1443 /* Only the initial fragment is time stamped */ 1444 skb_shinfo(skb)->tx_flags = cork->tx_flags; 1445 cork->tx_flags = 0; 1446 skb_shinfo(skb)->tskey = tskey; 1447 tskey = 0; 1448 1449 /* 1450 * Find where to start putting bytes 1451 */ 1452 data = skb_put(skb, fraglen - pagedlen); 1453 skb_set_network_header(skb, exthdrlen); 1454 data += fragheaderlen; 1455 skb->transport_header = (skb->network_header + 1456 fragheaderlen); 1457 if (fraggap) { 1458 skb->csum = skb_copy_and_csum_bits( 1459 skb_prev, maxfraglen, 1460 data + transhdrlen, fraggap, 0); 1461 skb_prev->csum = csum_sub(skb_prev->csum, 1462 skb->csum); 1463 data += fraggap; 1464 pskb_trim_unique(skb_prev, maxfraglen); 1465 } 1466 if (copy > 0 && 1467 getfrag(from, data + transhdrlen, offset, 1468 copy, fraggap, skb) < 0) { 1469 err = -EFAULT; 1470 kfree_skb(skb); 1471 goto error; 1472 } 1473 1474 offset += copy; 1475 length -= copy + transhdrlen; 1476 transhdrlen = 0; 1477 exthdrlen = 0; 1478 dst_exthdrlen = 0; 1479 1480 if ((flags & MSG_CONFIRM) && !skb_prev) 1481 skb_set_dst_pending_confirm(skb, 1); 1482 1483 /* 1484 * Put the packet on the pending queue 1485 */ 1486 if (!skb->destructor) { 1487 skb->destructor = sock_wfree; 1488 skb->sk = sk; 1489 wmem_alloc_delta += skb->truesize; 1490 } 1491 __skb_queue_tail(queue, skb); 1492 continue; 1493 } 1494 1495 if (copy > length) 1496 copy = length; 1497 1498 if (!(rt->dst.dev->features&NETIF_F_SG) && 1499 skb_tailroom(skb) >= copy) { 1500 unsigned int off; 1501 1502 off = skb->len; 1503 if (getfrag(from, skb_put(skb, copy), 1504 offset, copy, off, skb) < 0) { 1505 __skb_trim(skb, off); 1506 err = -EFAULT; 1507 goto error; 1508 } 1509 } else { 1510 int i = skb_shinfo(skb)->nr_frags; 1511 1512 err = -ENOMEM; 1513 if (!sk_page_frag_refill(sk, pfrag)) 1514 goto error; 1515 1516 if (!skb_can_coalesce(skb, i, pfrag->page, 1517 pfrag->offset)) { 1518 err = -EMSGSIZE; 1519 if (i == MAX_SKB_FRAGS) 1520 goto error; 1521 1522 __skb_fill_page_desc(skb, i, pfrag->page, 1523 pfrag->offset, 0); 1524 skb_shinfo(skb)->nr_frags = ++i; 1525 get_page(pfrag->page); 1526 } 1527 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1528 if (getfrag(from, 1529 page_address(pfrag->page) + pfrag->offset, 1530 offset, copy, skb->len, skb) < 0) 1531 goto error_efault; 1532 1533 pfrag->offset += copy; 1534 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1535 skb->len += copy; 1536 skb->data_len += copy; 1537 skb->truesize += copy; 1538 wmem_alloc_delta += copy; 1539 } 1540 offset += copy; 1541 length -= copy; 1542 } 1543 1544 if (wmem_alloc_delta) 1545 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1546 return 0; 1547 1548 error_efault: 1549 err = -EFAULT; 1550 error: 1551 cork->length -= length; 1552 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1553 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1554 return err; 1555 } 1556 1557 int ip6_append_data(struct sock *sk, 1558 int getfrag(void *from, char *to, int offset, int len, 1559 int odd, struct sk_buff *skb), 1560 void *from, int length, int transhdrlen, 1561 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1562 struct rt6_info *rt, unsigned int flags) 1563 { 1564 struct inet_sock *inet = inet_sk(sk); 1565 struct ipv6_pinfo *np = inet6_sk(sk); 1566 int exthdrlen; 1567 int err; 1568 1569 if (flags&MSG_PROBE) 1570 return 0; 1571 if (skb_queue_empty(&sk->sk_write_queue)) { 1572 /* 1573 * setup for corking 1574 */ 1575 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1576 ipc6, rt, fl6); 1577 if (err) 1578 return err; 1579 1580 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1581 length += exthdrlen; 1582 transhdrlen += exthdrlen; 1583 } else { 1584 fl6 = &inet->cork.fl.u.ip6; 1585 transhdrlen = 0; 1586 } 1587 1588 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1589 &np->cork, sk_page_frag(sk), getfrag, 1590 from, length, transhdrlen, flags, ipc6); 1591 } 1592 EXPORT_SYMBOL_GPL(ip6_append_data); 1593 1594 static void ip6_cork_release(struct inet_cork_full *cork, 1595 struct inet6_cork *v6_cork) 1596 { 1597 if (v6_cork->opt) { 1598 kfree(v6_cork->opt->dst0opt); 1599 kfree(v6_cork->opt->dst1opt); 1600 kfree(v6_cork->opt->hopopt); 1601 kfree(v6_cork->opt->srcrt); 1602 kfree(v6_cork->opt); 1603 v6_cork->opt = NULL; 1604 } 1605 1606 if (cork->base.dst) { 1607 dst_release(cork->base.dst); 1608 cork->base.dst = NULL; 1609 cork->base.flags &= ~IPCORK_ALLFRAG; 1610 } 1611 memset(&cork->fl, 0, sizeof(cork->fl)); 1612 } 1613 1614 struct sk_buff *__ip6_make_skb(struct sock *sk, 1615 struct sk_buff_head *queue, 1616 struct inet_cork_full *cork, 1617 struct inet6_cork *v6_cork) 1618 { 1619 struct sk_buff *skb, *tmp_skb; 1620 struct sk_buff **tail_skb; 1621 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1622 struct ipv6_pinfo *np = inet6_sk(sk); 1623 struct net *net = sock_net(sk); 1624 struct ipv6hdr *hdr; 1625 struct ipv6_txoptions *opt = v6_cork->opt; 1626 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1627 struct flowi6 *fl6 = &cork->fl.u.ip6; 1628 unsigned char proto = fl6->flowi6_proto; 1629 1630 skb = __skb_dequeue(queue); 1631 if (!skb) 1632 goto out; 1633 tail_skb = &(skb_shinfo(skb)->frag_list); 1634 1635 /* move skb->data to ip header from ext header */ 1636 if (skb->data < skb_network_header(skb)) 1637 __skb_pull(skb, skb_network_offset(skb)); 1638 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1639 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1640 *tail_skb = tmp_skb; 1641 tail_skb = &(tmp_skb->next); 1642 skb->len += tmp_skb->len; 1643 skb->data_len += tmp_skb->len; 1644 skb->truesize += tmp_skb->truesize; 1645 tmp_skb->destructor = NULL; 1646 tmp_skb->sk = NULL; 1647 } 1648 1649 /* Allow local fragmentation. */ 1650 skb->ignore_df = ip6_sk_ignore_df(sk); 1651 1652 *final_dst = fl6->daddr; 1653 __skb_pull(skb, skb_network_header_len(skb)); 1654 if (opt && opt->opt_flen) 1655 ipv6_push_frag_opts(skb, opt, &proto); 1656 if (opt && opt->opt_nflen) 1657 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1658 1659 skb_push(skb, sizeof(struct ipv6hdr)); 1660 skb_reset_network_header(skb); 1661 hdr = ipv6_hdr(skb); 1662 1663 ip6_flow_hdr(hdr, v6_cork->tclass, 1664 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1665 ip6_autoflowlabel(net, np), fl6)); 1666 hdr->hop_limit = v6_cork->hop_limit; 1667 hdr->nexthdr = proto; 1668 hdr->saddr = fl6->saddr; 1669 hdr->daddr = *final_dst; 1670 1671 skb->priority = sk->sk_priority; 1672 skb->mark = sk->sk_mark; 1673 1674 skb->tstamp = cork->base.transmit_time; 1675 1676 skb_dst_set(skb, dst_clone(&rt->dst)); 1677 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1678 if (proto == IPPROTO_ICMPV6) { 1679 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1680 1681 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1682 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1683 } 1684 1685 ip6_cork_release(cork, v6_cork); 1686 out: 1687 return skb; 1688 } 1689 1690 int ip6_send_skb(struct sk_buff *skb) 1691 { 1692 struct net *net = sock_net(skb->sk); 1693 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1694 int err; 1695 1696 err = ip6_local_out(net, skb->sk, skb); 1697 if (err) { 1698 if (err > 0) 1699 err = net_xmit_errno(err); 1700 if (err) 1701 IP6_INC_STATS(net, rt->rt6i_idev, 1702 IPSTATS_MIB_OUTDISCARDS); 1703 } 1704 1705 return err; 1706 } 1707 1708 int ip6_push_pending_frames(struct sock *sk) 1709 { 1710 struct sk_buff *skb; 1711 1712 skb = ip6_finish_skb(sk); 1713 if (!skb) 1714 return 0; 1715 1716 return ip6_send_skb(skb); 1717 } 1718 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1719 1720 static void __ip6_flush_pending_frames(struct sock *sk, 1721 struct sk_buff_head *queue, 1722 struct inet_cork_full *cork, 1723 struct inet6_cork *v6_cork) 1724 { 1725 struct sk_buff *skb; 1726 1727 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1728 if (skb_dst(skb)) 1729 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1730 IPSTATS_MIB_OUTDISCARDS); 1731 kfree_skb(skb); 1732 } 1733 1734 ip6_cork_release(cork, v6_cork); 1735 } 1736 1737 void ip6_flush_pending_frames(struct sock *sk) 1738 { 1739 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1740 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1741 } 1742 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1743 1744 struct sk_buff *ip6_make_skb(struct sock *sk, 1745 int getfrag(void *from, char *to, int offset, 1746 int len, int odd, struct sk_buff *skb), 1747 void *from, int length, int transhdrlen, 1748 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1749 struct rt6_info *rt, unsigned int flags, 1750 struct inet_cork_full *cork) 1751 { 1752 struct inet6_cork v6_cork; 1753 struct sk_buff_head queue; 1754 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1755 int err; 1756 1757 if (flags & MSG_PROBE) 1758 return NULL; 1759 1760 __skb_queue_head_init(&queue); 1761 1762 cork->base.flags = 0; 1763 cork->base.addr = 0; 1764 cork->base.opt = NULL; 1765 cork->base.dst = NULL; 1766 v6_cork.opt = NULL; 1767 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6); 1768 if (err) { 1769 ip6_cork_release(cork, &v6_cork); 1770 return ERR_PTR(err); 1771 } 1772 if (ipc6->dontfrag < 0) 1773 ipc6->dontfrag = inet6_sk(sk)->dontfrag; 1774 1775 err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork, 1776 ¤t->task_frag, getfrag, from, 1777 length + exthdrlen, transhdrlen + exthdrlen, 1778 flags, ipc6); 1779 if (err) { 1780 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); 1781 return ERR_PTR(err); 1782 } 1783 1784 return __ip6_make_skb(sk, &queue, cork, &v6_cork); 1785 } 1786