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 = 0; 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 1382 if ((flags & MSG_MORE) && 1383 !(rt->dst.dev->features&NETIF_F_SG)) 1384 alloclen = mtu; 1385 else if (!paged) 1386 alloclen = fraglen; 1387 else { 1388 alloclen = min_t(int, fraglen, MAX_HEADER); 1389 pagedlen = fraglen - alloclen; 1390 } 1391 1392 alloclen += dst_exthdrlen; 1393 1394 if (datalen != length + fraggap) { 1395 /* 1396 * this is not the last fragment, the trailer 1397 * space is regarded as data space. 1398 */ 1399 datalen += rt->dst.trailer_len; 1400 } 1401 1402 alloclen += rt->dst.trailer_len; 1403 fraglen = datalen + fragheaderlen; 1404 1405 /* 1406 * We just reserve space for fragment header. 1407 * Note: this may be overallocation if the message 1408 * (without MSG_MORE) fits into the MTU. 1409 */ 1410 alloclen += sizeof(struct frag_hdr); 1411 1412 copy = datalen - transhdrlen - fraggap - pagedlen; 1413 if (copy < 0) { 1414 err = -EINVAL; 1415 goto error; 1416 } 1417 if (transhdrlen) { 1418 skb = sock_alloc_send_skb(sk, 1419 alloclen + hh_len, 1420 (flags & MSG_DONTWAIT), &err); 1421 } else { 1422 skb = NULL; 1423 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 1424 2 * sk->sk_sndbuf) 1425 skb = alloc_skb(alloclen + hh_len, 1426 sk->sk_allocation); 1427 if (unlikely(!skb)) 1428 err = -ENOBUFS; 1429 } 1430 if (!skb) 1431 goto error; 1432 /* 1433 * Fill in the control structures 1434 */ 1435 skb->protocol = htons(ETH_P_IPV6); 1436 skb->ip_summed = csummode; 1437 skb->csum = 0; 1438 /* reserve for fragmentation and ipsec header */ 1439 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) + 1440 dst_exthdrlen); 1441 1442 /* Only the initial fragment is time stamped */ 1443 skb_shinfo(skb)->tx_flags = cork->tx_flags; 1444 cork->tx_flags = 0; 1445 skb_shinfo(skb)->tskey = tskey; 1446 tskey = 0; 1447 1448 /* 1449 * Find where to start putting bytes 1450 */ 1451 data = skb_put(skb, fraglen - pagedlen); 1452 skb_set_network_header(skb, exthdrlen); 1453 data += fragheaderlen; 1454 skb->transport_header = (skb->network_header + 1455 fragheaderlen); 1456 if (fraggap) { 1457 skb->csum = skb_copy_and_csum_bits( 1458 skb_prev, maxfraglen, 1459 data + transhdrlen, fraggap, 0); 1460 skb_prev->csum = csum_sub(skb_prev->csum, 1461 skb->csum); 1462 data += fraggap; 1463 pskb_trim_unique(skb_prev, maxfraglen); 1464 } 1465 if (copy > 0 && 1466 getfrag(from, data + transhdrlen, offset, 1467 copy, fraggap, skb) < 0) { 1468 err = -EFAULT; 1469 kfree_skb(skb); 1470 goto error; 1471 } 1472 1473 offset += copy; 1474 length -= copy + transhdrlen; 1475 transhdrlen = 0; 1476 exthdrlen = 0; 1477 dst_exthdrlen = 0; 1478 1479 if ((flags & MSG_CONFIRM) && !skb_prev) 1480 skb_set_dst_pending_confirm(skb, 1); 1481 1482 /* 1483 * Put the packet on the pending queue 1484 */ 1485 if (!skb->destructor) { 1486 skb->destructor = sock_wfree; 1487 skb->sk = sk; 1488 wmem_alloc_delta += skb->truesize; 1489 } 1490 __skb_queue_tail(queue, skb); 1491 continue; 1492 } 1493 1494 if (copy > length) 1495 copy = length; 1496 1497 if (!(rt->dst.dev->features&NETIF_F_SG) && 1498 skb_tailroom(skb) >= copy) { 1499 unsigned int off; 1500 1501 off = skb->len; 1502 if (getfrag(from, skb_put(skb, copy), 1503 offset, copy, off, skb) < 0) { 1504 __skb_trim(skb, off); 1505 err = -EFAULT; 1506 goto error; 1507 } 1508 } else { 1509 int i = skb_shinfo(skb)->nr_frags; 1510 1511 err = -ENOMEM; 1512 if (!sk_page_frag_refill(sk, pfrag)) 1513 goto error; 1514 1515 if (!skb_can_coalesce(skb, i, pfrag->page, 1516 pfrag->offset)) { 1517 err = -EMSGSIZE; 1518 if (i == MAX_SKB_FRAGS) 1519 goto error; 1520 1521 __skb_fill_page_desc(skb, i, pfrag->page, 1522 pfrag->offset, 0); 1523 skb_shinfo(skb)->nr_frags = ++i; 1524 get_page(pfrag->page); 1525 } 1526 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1527 if (getfrag(from, 1528 page_address(pfrag->page) + pfrag->offset, 1529 offset, copy, skb->len, skb) < 0) 1530 goto error_efault; 1531 1532 pfrag->offset += copy; 1533 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1534 skb->len += copy; 1535 skb->data_len += copy; 1536 skb->truesize += copy; 1537 wmem_alloc_delta += copy; 1538 } 1539 offset += copy; 1540 length -= copy; 1541 } 1542 1543 if (wmem_alloc_delta) 1544 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1545 return 0; 1546 1547 error_efault: 1548 err = -EFAULT; 1549 error: 1550 cork->length -= length; 1551 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); 1552 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); 1553 return err; 1554 } 1555 1556 int ip6_append_data(struct sock *sk, 1557 int getfrag(void *from, char *to, int offset, int len, 1558 int odd, struct sk_buff *skb), 1559 void *from, int length, int transhdrlen, 1560 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1561 struct rt6_info *rt, unsigned int flags) 1562 { 1563 struct inet_sock *inet = inet_sk(sk); 1564 struct ipv6_pinfo *np = inet6_sk(sk); 1565 int exthdrlen; 1566 int err; 1567 1568 if (flags&MSG_PROBE) 1569 return 0; 1570 if (skb_queue_empty(&sk->sk_write_queue)) { 1571 /* 1572 * setup for corking 1573 */ 1574 err = ip6_setup_cork(sk, &inet->cork, &np->cork, 1575 ipc6, rt, fl6); 1576 if (err) 1577 return err; 1578 1579 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1580 length += exthdrlen; 1581 transhdrlen += exthdrlen; 1582 } else { 1583 fl6 = &inet->cork.fl.u.ip6; 1584 transhdrlen = 0; 1585 } 1586 1587 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, 1588 &np->cork, sk_page_frag(sk), getfrag, 1589 from, length, transhdrlen, flags, ipc6); 1590 } 1591 EXPORT_SYMBOL_GPL(ip6_append_data); 1592 1593 static void ip6_cork_release(struct inet_cork_full *cork, 1594 struct inet6_cork *v6_cork) 1595 { 1596 if (v6_cork->opt) { 1597 kfree(v6_cork->opt->dst0opt); 1598 kfree(v6_cork->opt->dst1opt); 1599 kfree(v6_cork->opt->hopopt); 1600 kfree(v6_cork->opt->srcrt); 1601 kfree(v6_cork->opt); 1602 v6_cork->opt = NULL; 1603 } 1604 1605 if (cork->base.dst) { 1606 dst_release(cork->base.dst); 1607 cork->base.dst = NULL; 1608 cork->base.flags &= ~IPCORK_ALLFRAG; 1609 } 1610 memset(&cork->fl, 0, sizeof(cork->fl)); 1611 } 1612 1613 struct sk_buff *__ip6_make_skb(struct sock *sk, 1614 struct sk_buff_head *queue, 1615 struct inet_cork_full *cork, 1616 struct inet6_cork *v6_cork) 1617 { 1618 struct sk_buff *skb, *tmp_skb; 1619 struct sk_buff **tail_skb; 1620 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1621 struct ipv6_pinfo *np = inet6_sk(sk); 1622 struct net *net = sock_net(sk); 1623 struct ipv6hdr *hdr; 1624 struct ipv6_txoptions *opt = v6_cork->opt; 1625 struct rt6_info *rt = (struct rt6_info *)cork->base.dst; 1626 struct flowi6 *fl6 = &cork->fl.u.ip6; 1627 unsigned char proto = fl6->flowi6_proto; 1628 1629 skb = __skb_dequeue(queue); 1630 if (!skb) 1631 goto out; 1632 tail_skb = &(skb_shinfo(skb)->frag_list); 1633 1634 /* move skb->data to ip header from ext header */ 1635 if (skb->data < skb_network_header(skb)) 1636 __skb_pull(skb, skb_network_offset(skb)); 1637 while ((tmp_skb = __skb_dequeue(queue)) != NULL) { 1638 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1639 *tail_skb = tmp_skb; 1640 tail_skb = &(tmp_skb->next); 1641 skb->len += tmp_skb->len; 1642 skb->data_len += tmp_skb->len; 1643 skb->truesize += tmp_skb->truesize; 1644 tmp_skb->destructor = NULL; 1645 tmp_skb->sk = NULL; 1646 } 1647 1648 /* Allow local fragmentation. */ 1649 skb->ignore_df = ip6_sk_ignore_df(sk); 1650 1651 *final_dst = fl6->daddr; 1652 __skb_pull(skb, skb_network_header_len(skb)); 1653 if (opt && opt->opt_flen) 1654 ipv6_push_frag_opts(skb, opt, &proto); 1655 if (opt && opt->opt_nflen) 1656 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr); 1657 1658 skb_push(skb, sizeof(struct ipv6hdr)); 1659 skb_reset_network_header(skb); 1660 hdr = ipv6_hdr(skb); 1661 1662 ip6_flow_hdr(hdr, v6_cork->tclass, 1663 ip6_make_flowlabel(net, skb, fl6->flowlabel, 1664 ip6_autoflowlabel(net, np), fl6)); 1665 hdr->hop_limit = v6_cork->hop_limit; 1666 hdr->nexthdr = proto; 1667 hdr->saddr = fl6->saddr; 1668 hdr->daddr = *final_dst; 1669 1670 skb->priority = sk->sk_priority; 1671 skb->mark = sk->sk_mark; 1672 1673 skb->tstamp = cork->base.transmit_time; 1674 1675 skb_dst_set(skb, dst_clone(&rt->dst)); 1676 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); 1677 if (proto == IPPROTO_ICMPV6) { 1678 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); 1679 1680 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type); 1681 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); 1682 } 1683 1684 ip6_cork_release(cork, v6_cork); 1685 out: 1686 return skb; 1687 } 1688 1689 int ip6_send_skb(struct sk_buff *skb) 1690 { 1691 struct net *net = sock_net(skb->sk); 1692 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); 1693 int err; 1694 1695 err = ip6_local_out(net, skb->sk, skb); 1696 if (err) { 1697 if (err > 0) 1698 err = net_xmit_errno(err); 1699 if (err) 1700 IP6_INC_STATS(net, rt->rt6i_idev, 1701 IPSTATS_MIB_OUTDISCARDS); 1702 } 1703 1704 return err; 1705 } 1706 1707 int ip6_push_pending_frames(struct sock *sk) 1708 { 1709 struct sk_buff *skb; 1710 1711 skb = ip6_finish_skb(sk); 1712 if (!skb) 1713 return 0; 1714 1715 return ip6_send_skb(skb); 1716 } 1717 EXPORT_SYMBOL_GPL(ip6_push_pending_frames); 1718 1719 static void __ip6_flush_pending_frames(struct sock *sk, 1720 struct sk_buff_head *queue, 1721 struct inet_cork_full *cork, 1722 struct inet6_cork *v6_cork) 1723 { 1724 struct sk_buff *skb; 1725 1726 while ((skb = __skb_dequeue_tail(queue)) != NULL) { 1727 if (skb_dst(skb)) 1728 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)), 1729 IPSTATS_MIB_OUTDISCARDS); 1730 kfree_skb(skb); 1731 } 1732 1733 ip6_cork_release(cork, v6_cork); 1734 } 1735 1736 void ip6_flush_pending_frames(struct sock *sk) 1737 { 1738 __ip6_flush_pending_frames(sk, &sk->sk_write_queue, 1739 &inet_sk(sk)->cork, &inet6_sk(sk)->cork); 1740 } 1741 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); 1742 1743 struct sk_buff *ip6_make_skb(struct sock *sk, 1744 int getfrag(void *from, char *to, int offset, 1745 int len, int odd, struct sk_buff *skb), 1746 void *from, int length, int transhdrlen, 1747 struct ipcm6_cookie *ipc6, struct flowi6 *fl6, 1748 struct rt6_info *rt, unsigned int flags, 1749 struct inet_cork_full *cork) 1750 { 1751 struct inet6_cork v6_cork; 1752 struct sk_buff_head queue; 1753 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0); 1754 int err; 1755 1756 if (flags & MSG_PROBE) 1757 return NULL; 1758 1759 __skb_queue_head_init(&queue); 1760 1761 cork->base.flags = 0; 1762 cork->base.addr = 0; 1763 cork->base.opt = NULL; 1764 cork->base.dst = NULL; 1765 v6_cork.opt = NULL; 1766 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6); 1767 if (err) { 1768 ip6_cork_release(cork, &v6_cork); 1769 return ERR_PTR(err); 1770 } 1771 if (ipc6->dontfrag < 0) 1772 ipc6->dontfrag = inet6_sk(sk)->dontfrag; 1773 1774 err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork, 1775 ¤t->task_frag, getfrag, from, 1776 length + exthdrlen, transhdrlen + exthdrlen, 1777 flags, ipc6); 1778 if (err) { 1779 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); 1780 return ERR_PTR(err); 1781 } 1782 1783 return __ip6_make_skb(sk, &queue, cork, &v6_cork); 1784 } 1785