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