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