1 /* 2 * IPv6 output functions 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $ 9 * 10 * Based on linux/net/ipv4/ip_output.c 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Changes: 18 * A.N.Kuznetsov : airthmetics in fragmentation. 19 * extension headers are implemented. 20 * route changes now work. 21 * ip6_forward does not confuse sniffers. 22 * etc. 23 * 24 * H. von Brand : Added missing #include <linux/string.h> 25 * Imran Patel : frag id should be in NBO 26 * Kazunori MIYAZAWA @USAGI 27 * : add ip6_append_data and related functions 28 * for datagram xmit 29 */ 30 31 #include <linux/errno.h> 32 #include <linux/types.h> 33 #include <linux/string.h> 34 #include <linux/socket.h> 35 #include <linux/net.h> 36 #include <linux/netdevice.h> 37 #include <linux/if_arp.h> 38 #include <linux/in6.h> 39 #include <linux/tcp.h> 40 #include <linux/route.h> 41 #include <linux/module.h> 42 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 59 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)); 60 61 static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr) 62 { 63 static u32 ipv6_fragmentation_id = 1; 64 static DEFINE_SPINLOCK(ip6_id_lock); 65 66 spin_lock_bh(&ip6_id_lock); 67 fhdr->identification = htonl(ipv6_fragmentation_id); 68 if (++ipv6_fragmentation_id == 0) 69 ipv6_fragmentation_id = 1; 70 spin_unlock_bh(&ip6_id_lock); 71 } 72 73 static inline int ip6_output_finish(struct sk_buff *skb) 74 { 75 76 struct dst_entry *dst = skb->dst; 77 struct hh_cache *hh = dst->hh; 78 79 if (hh) { 80 int hh_alen; 81 82 read_lock_bh(&hh->hh_lock); 83 hh_alen = HH_DATA_ALIGN(hh->hh_len); 84 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 85 read_unlock_bh(&hh->hh_lock); 86 skb_push(skb, hh->hh_len); 87 return hh->hh_output(skb); 88 } else if (dst->neighbour) 89 return dst->neighbour->output(skb); 90 91 IP6_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); 92 kfree_skb(skb); 93 return -EINVAL; 94 95 } 96 97 /* dev_loopback_xmit for use with netfilter. */ 98 static int ip6_dev_loopback_xmit(struct sk_buff *newskb) 99 { 100 newskb->mac.raw = newskb->data; 101 __skb_pull(newskb, newskb->nh.raw - newskb->data); 102 newskb->pkt_type = PACKET_LOOPBACK; 103 newskb->ip_summed = CHECKSUM_UNNECESSARY; 104 BUG_TRAP(newskb->dst); 105 106 netif_rx(newskb); 107 return 0; 108 } 109 110 111 static int ip6_output2(struct sk_buff *skb) 112 { 113 struct dst_entry *dst = skb->dst; 114 struct net_device *dev = dst->dev; 115 116 skb->protocol = htons(ETH_P_IPV6); 117 skb->dev = dev; 118 119 if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr)) { 120 struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL; 121 122 if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) && 123 ipv6_chk_mcast_addr(dev, &skb->nh.ipv6h->daddr, 124 &skb->nh.ipv6h->saddr)) { 125 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 126 127 /* Do not check for IFF_ALLMULTI; multicast routing 128 is not supported in any case. 129 */ 130 if (newskb) 131 NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL, 132 newskb->dev, 133 ip6_dev_loopback_xmit); 134 135 if (skb->nh.ipv6h->hop_limit == 0) { 136 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 137 kfree_skb(skb); 138 return 0; 139 } 140 } 141 142 IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS); 143 } 144 145 return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish); 146 } 147 148 int ip6_output(struct sk_buff *skb) 149 { 150 if ((skb->len > dst_mtu(skb->dst) && !skb_is_gso(skb)) || 151 dst_allfrag(skb->dst)) 152 return ip6_fragment(skb, ip6_output2); 153 else 154 return ip6_output2(skb); 155 } 156 157 /* 158 * xmit an sk_buff (used by TCP) 159 */ 160 161 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, 162 struct ipv6_txoptions *opt, int ipfragok) 163 { 164 struct ipv6_pinfo *np = inet6_sk(sk); 165 struct in6_addr *first_hop = &fl->fl6_dst; 166 struct dst_entry *dst = skb->dst; 167 struct ipv6hdr *hdr; 168 u8 proto = fl->proto; 169 int seg_len = skb->len; 170 int hlimit, tclass; 171 u32 mtu; 172 173 if (opt) { 174 int head_room; 175 176 /* First: exthdrs may take lots of space (~8K for now) 177 MAX_HEADER is not enough. 178 */ 179 head_room = opt->opt_nflen + opt->opt_flen; 180 seg_len += head_room; 181 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); 182 183 if (skb_headroom(skb) < head_room) { 184 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); 185 kfree_skb(skb); 186 skb = skb2; 187 if (skb == NULL) { 188 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 189 return -ENOBUFS; 190 } 191 if (sk) 192 skb_set_owner_w(skb, sk); 193 } 194 if (opt->opt_flen) 195 ipv6_push_frag_opts(skb, opt, &proto); 196 if (opt->opt_nflen) 197 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); 198 } 199 200 hdr = skb->nh.ipv6h = (struct ipv6hdr*)skb_push(skb, sizeof(struct ipv6hdr)); 201 202 /* 203 * Fill in the IPv6 header 204 */ 205 206 hlimit = -1; 207 if (np) 208 hlimit = np->hop_limit; 209 if (hlimit < 0) 210 hlimit = dst_metric(dst, RTAX_HOPLIMIT); 211 if (hlimit < 0) 212 hlimit = ipv6_get_hoplimit(dst->dev); 213 214 tclass = -1; 215 if (np) 216 tclass = np->tclass; 217 if (tclass < 0) 218 tclass = 0; 219 220 *(u32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel; 221 222 hdr->payload_len = htons(seg_len); 223 hdr->nexthdr = proto; 224 hdr->hop_limit = hlimit; 225 226 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 227 ipv6_addr_copy(&hdr->daddr, first_hop); 228 229 skb->priority = sk->sk_priority; 230 231 mtu = dst_mtu(dst); 232 if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) { 233 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 234 return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev, 235 dst_output); 236 } 237 238 if (net_ratelimit()) 239 printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n"); 240 skb->dev = dst->dev; 241 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); 242 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 243 kfree_skb(skb); 244 return -EMSGSIZE; 245 } 246 247 /* 248 * To avoid extra problems ND packets are send through this 249 * routine. It's code duplication but I really want to avoid 250 * extra checks since ipv6_build_header is used by TCP (which 251 * is for us performance critical) 252 */ 253 254 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev, 255 struct in6_addr *saddr, struct in6_addr *daddr, 256 int proto, int len) 257 { 258 struct ipv6_pinfo *np = inet6_sk(sk); 259 struct ipv6hdr *hdr; 260 int totlen; 261 262 skb->protocol = htons(ETH_P_IPV6); 263 skb->dev = dev; 264 265 totlen = len + sizeof(struct ipv6hdr); 266 267 hdr = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr)); 268 skb->nh.ipv6h = hdr; 269 270 *(u32*)hdr = htonl(0x60000000); 271 272 hdr->payload_len = htons(len); 273 hdr->nexthdr = proto; 274 hdr->hop_limit = np->hop_limit; 275 276 ipv6_addr_copy(&hdr->saddr, saddr); 277 ipv6_addr_copy(&hdr->daddr, daddr); 278 279 return 0; 280 } 281 282 static int ip6_call_ra_chain(struct sk_buff *skb, int sel) 283 { 284 struct ip6_ra_chain *ra; 285 struct sock *last = NULL; 286 287 read_lock(&ip6_ra_lock); 288 for (ra = ip6_ra_chain; ra; ra = ra->next) { 289 struct sock *sk = ra->sk; 290 if (sk && ra->sel == sel && 291 (!sk->sk_bound_dev_if || 292 sk->sk_bound_dev_if == skb->dev->ifindex)) { 293 if (last) { 294 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 295 if (skb2) 296 rawv6_rcv(last, skb2); 297 } 298 last = sk; 299 } 300 } 301 302 if (last) { 303 rawv6_rcv(last, skb); 304 read_unlock(&ip6_ra_lock); 305 return 1; 306 } 307 read_unlock(&ip6_ra_lock); 308 return 0; 309 } 310 311 static inline int ip6_forward_finish(struct sk_buff *skb) 312 { 313 return dst_output(skb); 314 } 315 316 int ip6_forward(struct sk_buff *skb) 317 { 318 struct dst_entry *dst = skb->dst; 319 struct ipv6hdr *hdr = skb->nh.ipv6h; 320 struct inet6_skb_parm *opt = IP6CB(skb); 321 322 if (ipv6_devconf.forwarding == 0) 323 goto error; 324 325 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { 326 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS); 327 goto drop; 328 } 329 330 skb->ip_summed = CHECKSUM_NONE; 331 332 /* 333 * We DO NOT make any processing on 334 * RA packets, pushing them to user level AS IS 335 * without ane WARRANTY that application will be able 336 * to interpret them. The reason is that we 337 * cannot make anything clever here. 338 * 339 * We are not end-node, so that if packet contains 340 * AH/ESP, we cannot make anything. 341 * Defragmentation also would be mistake, RA packets 342 * cannot be fragmented, because there is no warranty 343 * that different fragments will go along one path. --ANK 344 */ 345 if (opt->ra) { 346 u8 *ptr = skb->nh.raw + opt->ra; 347 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3])) 348 return 0; 349 } 350 351 /* 352 * check and decrement ttl 353 */ 354 if (hdr->hop_limit <= 1) { 355 /* Force OUTPUT device used as source address */ 356 skb->dev = dst->dev; 357 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 358 0, skb->dev); 359 360 kfree_skb(skb); 361 return -ETIMEDOUT; 362 } 363 364 if (!xfrm6_route_forward(skb)) { 365 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS); 366 goto drop; 367 } 368 dst = skb->dst; 369 370 /* IPv6 specs say nothing about it, but it is clear that we cannot 371 send redirects to source routed frames. 372 */ 373 if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) { 374 struct in6_addr *target = NULL; 375 struct rt6_info *rt; 376 struct neighbour *n = dst->neighbour; 377 378 /* 379 * incoming and outgoing devices are the same 380 * send a redirect. 381 */ 382 383 rt = (struct rt6_info *) dst; 384 if ((rt->rt6i_flags & RTF_GATEWAY)) 385 target = (struct in6_addr*)&n->primary_key; 386 else 387 target = &hdr->daddr; 388 389 /* Limit redirects both by destination (here) 390 and by source (inside ndisc_send_redirect) 391 */ 392 if (xrlim_allow(dst, 1*HZ)) 393 ndisc_send_redirect(skb, n, target); 394 } else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK 395 |IPV6_ADDR_LINKLOCAL)) { 396 /* This check is security critical. */ 397 goto error; 398 } 399 400 if (skb->len > dst_mtu(dst)) { 401 /* Again, force OUTPUT device used as source address */ 402 skb->dev = dst->dev; 403 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev); 404 IP6_INC_STATS_BH(IPSTATS_MIB_INTOOBIGERRORS); 405 IP6_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS); 406 kfree_skb(skb); 407 return -EMSGSIZE; 408 } 409 410 if (skb_cow(skb, dst->dev->hard_header_len)) { 411 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 412 goto drop; 413 } 414 415 hdr = skb->nh.ipv6h; 416 417 /* Mangling hops number delayed to point after skb COW */ 418 419 hdr->hop_limit--; 420 421 IP6_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS); 422 return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish); 423 424 error: 425 IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS); 426 drop: 427 kfree_skb(skb); 428 return -EINVAL; 429 } 430 431 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 432 { 433 to->pkt_type = from->pkt_type; 434 to->priority = from->priority; 435 to->protocol = from->protocol; 436 dst_release(to->dst); 437 to->dst = dst_clone(from->dst); 438 to->dev = from->dev; 439 440 #ifdef CONFIG_NET_SCHED 441 to->tc_index = from->tc_index; 442 #endif 443 #ifdef CONFIG_NETFILTER 444 to->nfmark = from->nfmark; 445 /* Connection association is same as pre-frag packet */ 446 nf_conntrack_put(to->nfct); 447 to->nfct = from->nfct; 448 nf_conntrack_get(to->nfct); 449 to->nfctinfo = from->nfctinfo; 450 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 451 nf_conntrack_put_reasm(to->nfct_reasm); 452 to->nfct_reasm = from->nfct_reasm; 453 nf_conntrack_get_reasm(to->nfct_reasm); 454 #endif 455 #ifdef CONFIG_BRIDGE_NETFILTER 456 nf_bridge_put(to->nf_bridge); 457 to->nf_bridge = from->nf_bridge; 458 nf_bridge_get(to->nf_bridge); 459 #endif 460 #endif 461 skb_copy_secmark(to, from); 462 } 463 464 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 465 { 466 u16 offset = sizeof(struct ipv6hdr); 467 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); 468 unsigned int packet_len = skb->tail - skb->nh.raw; 469 int found_rhdr = 0; 470 *nexthdr = &skb->nh.ipv6h->nexthdr; 471 472 while (offset + 1 <= packet_len) { 473 474 switch (**nexthdr) { 475 476 case NEXTHDR_HOP: 477 case NEXTHDR_ROUTING: 478 case NEXTHDR_DEST: 479 if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1; 480 if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset; 481 offset += ipv6_optlen(exthdr); 482 *nexthdr = &exthdr->nexthdr; 483 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); 484 break; 485 default : 486 return offset; 487 } 488 } 489 490 return offset; 491 } 492 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt); 493 494 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 495 { 496 struct net_device *dev; 497 struct sk_buff *frag; 498 struct rt6_info *rt = (struct rt6_info*)skb->dst; 499 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 500 struct ipv6hdr *tmp_hdr; 501 struct frag_hdr *fh; 502 unsigned int mtu, hlen, left, len; 503 u32 frag_id = 0; 504 int ptr, offset = 0, err=0; 505 u8 *prevhdr, nexthdr = 0; 506 507 dev = rt->u.dst.dev; 508 hlen = ip6_find_1stfragopt(skb, &prevhdr); 509 nexthdr = *prevhdr; 510 511 mtu = dst_mtu(&rt->u.dst); 512 if (np && np->frag_size < mtu) { 513 if (np->frag_size) 514 mtu = np->frag_size; 515 } 516 mtu -= hlen + sizeof(struct frag_hdr); 517 518 if (skb_shinfo(skb)->frag_list) { 519 int first_len = skb_pagelen(skb); 520 521 if (first_len - hlen > mtu || 522 ((first_len - hlen) & 7) || 523 skb_cloned(skb)) 524 goto slow_path; 525 526 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 527 /* Correct geometry. */ 528 if (frag->len > mtu || 529 ((frag->len & 7) && frag->next) || 530 skb_headroom(frag) < hlen) 531 goto slow_path; 532 533 /* Partially cloned skb? */ 534 if (skb_shared(frag)) 535 goto slow_path; 536 537 BUG_ON(frag->sk); 538 if (skb->sk) { 539 sock_hold(skb->sk); 540 frag->sk = skb->sk; 541 frag->destructor = sock_wfree; 542 skb->truesize -= frag->truesize; 543 } 544 } 545 546 err = 0; 547 offset = 0; 548 frag = skb_shinfo(skb)->frag_list; 549 skb_shinfo(skb)->frag_list = NULL; 550 /* BUILD HEADER */ 551 552 tmp_hdr = kmalloc(hlen, GFP_ATOMIC); 553 if (!tmp_hdr) { 554 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 555 return -ENOMEM; 556 } 557 558 *prevhdr = NEXTHDR_FRAGMENT; 559 memcpy(tmp_hdr, skb->nh.raw, hlen); 560 __skb_pull(skb, hlen); 561 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 562 skb->nh.raw = __skb_push(skb, hlen); 563 memcpy(skb->nh.raw, tmp_hdr, hlen); 564 565 ipv6_select_ident(skb, fh); 566 fh->nexthdr = nexthdr; 567 fh->reserved = 0; 568 fh->frag_off = htons(IP6_MF); 569 frag_id = fh->identification; 570 571 first_len = skb_pagelen(skb); 572 skb->data_len = first_len - skb_headlen(skb); 573 skb->len = first_len; 574 skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr)); 575 576 577 for (;;) { 578 /* Prepare header of the next frame, 579 * before previous one went down. */ 580 if (frag) { 581 frag->ip_summed = CHECKSUM_NONE; 582 frag->h.raw = frag->data; 583 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 584 frag->nh.raw = __skb_push(frag, hlen); 585 memcpy(frag->nh.raw, tmp_hdr, hlen); 586 offset += skb->len - hlen - sizeof(struct frag_hdr); 587 fh->nexthdr = nexthdr; 588 fh->reserved = 0; 589 fh->frag_off = htons(offset); 590 if (frag->next != NULL) 591 fh->frag_off |= htons(IP6_MF); 592 fh->identification = frag_id; 593 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 594 ip6_copy_metadata(frag, skb); 595 } 596 597 err = output(skb); 598 if (err || !frag) 599 break; 600 601 skb = frag; 602 frag = skb->next; 603 skb->next = NULL; 604 } 605 606 kfree(tmp_hdr); 607 608 if (err == 0) { 609 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 610 return 0; 611 } 612 613 while (frag) { 614 skb = frag->next; 615 kfree_skb(frag); 616 frag = skb; 617 } 618 619 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 620 return err; 621 } 622 623 slow_path: 624 left = skb->len - hlen; /* Space per frame */ 625 ptr = hlen; /* Where to start from */ 626 627 /* 628 * Fragment the datagram. 629 */ 630 631 *prevhdr = NEXTHDR_FRAGMENT; 632 633 /* 634 * Keep copying data until we run out. 635 */ 636 while(left > 0) { 637 len = left; 638 /* IF: it doesn't fit, use 'mtu' - the data space left */ 639 if (len > mtu) 640 len = mtu; 641 /* IF: we are not sending upto and including the packet end 642 then align the next start on an eight byte boundary */ 643 if (len < left) { 644 len &= ~7; 645 } 646 /* 647 * Allocate buffer. 648 */ 649 650 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { 651 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 652 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 653 err = -ENOMEM; 654 goto fail; 655 } 656 657 /* 658 * Set up data on packet 659 */ 660 661 ip6_copy_metadata(frag, skb); 662 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev)); 663 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 664 frag->nh.raw = frag->data; 665 fh = (struct frag_hdr*)(frag->data + hlen); 666 frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr); 667 668 /* 669 * Charge the memory for the fragment to any owner 670 * it might possess 671 */ 672 if (skb->sk) 673 skb_set_owner_w(frag, skb->sk); 674 675 /* 676 * Copy the packet header into the new buffer. 677 */ 678 memcpy(frag->nh.raw, skb->data, hlen); 679 680 /* 681 * Build fragment header. 682 */ 683 fh->nexthdr = nexthdr; 684 fh->reserved = 0; 685 if (!frag_id) { 686 ipv6_select_ident(skb, fh); 687 frag_id = fh->identification; 688 } else 689 fh->identification = frag_id; 690 691 /* 692 * Copy a block of the IP datagram. 693 */ 694 if (skb_copy_bits(skb, ptr, frag->h.raw, len)) 695 BUG(); 696 left -= len; 697 698 fh->frag_off = htons(offset); 699 if (left > 0) 700 fh->frag_off |= htons(IP6_MF); 701 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 702 703 ptr += len; 704 offset += len; 705 706 /* 707 * Put this fragment into the sending queue. 708 */ 709 710 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES); 711 712 err = output(frag); 713 if (err) 714 goto fail; 715 } 716 kfree_skb(skb); 717 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 718 return err; 719 720 fail: 721 kfree_skb(skb); 722 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 723 return err; 724 } 725 726 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) 727 { 728 int err = 0; 729 730 *dst = NULL; 731 if (sk) { 732 struct ipv6_pinfo *np = inet6_sk(sk); 733 734 *dst = sk_dst_check(sk, np->dst_cookie); 735 if (*dst) { 736 struct rt6_info *rt = (struct rt6_info*)*dst; 737 738 /* Yes, checking route validity in not connected 739 * case is not very simple. Take into account, 740 * that we do not support routing by source, TOS, 741 * and MSG_DONTROUTE --ANK (980726) 742 * 743 * 1. If route was host route, check that 744 * cached destination is current. 745 * If it is network route, we still may 746 * check its validity using saved pointer 747 * to the last used address: daddr_cache. 748 * We do not want to save whole address now, 749 * (because main consumer of this service 750 * is tcp, which has not this problem), 751 * so that the last trick works only on connected 752 * sockets. 753 * 2. oif also should be the same. 754 */ 755 if (((rt->rt6i_dst.plen != 128 || 756 !ipv6_addr_equal(&fl->fl6_dst, 757 &rt->rt6i_dst.addr)) 758 && (np->daddr_cache == NULL || 759 !ipv6_addr_equal(&fl->fl6_dst, 760 np->daddr_cache))) 761 || (fl->oif && fl->oif != (*dst)->dev->ifindex)) { 762 dst_release(*dst); 763 *dst = NULL; 764 } 765 } 766 } 767 768 if (*dst == NULL) 769 *dst = ip6_route_output(sk, fl); 770 771 if ((err = (*dst)->error)) 772 goto out_err_release; 773 774 if (ipv6_addr_any(&fl->fl6_src)) { 775 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src); 776 777 if (err) 778 goto out_err_release; 779 } 780 781 return 0; 782 783 out_err_release: 784 dst_release(*dst); 785 *dst = NULL; 786 return err; 787 } 788 789 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 790 791 static inline int ip6_ufo_append_data(struct sock *sk, 792 int getfrag(void *from, char *to, int offset, int len, 793 int odd, struct sk_buff *skb), 794 void *from, int length, int hh_len, int fragheaderlen, 795 int transhdrlen, int mtu,unsigned int flags) 796 797 { 798 struct sk_buff *skb; 799 int err; 800 801 /* There is support for UDP large send offload by network 802 * device, so create one single skb packet containing complete 803 * udp datagram 804 */ 805 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 806 skb = sock_alloc_send_skb(sk, 807 hh_len + fragheaderlen + transhdrlen + 20, 808 (flags & MSG_DONTWAIT), &err); 809 if (skb == NULL) 810 return -ENOMEM; 811 812 /* reserve space for Hardware header */ 813 skb_reserve(skb, hh_len); 814 815 /* create space for UDP/IP header */ 816 skb_put(skb,fragheaderlen + transhdrlen); 817 818 /* initialize network header pointer */ 819 skb->nh.raw = skb->data; 820 821 /* initialize protocol header pointer */ 822 skb->h.raw = skb->data + fragheaderlen; 823 824 skb->ip_summed = CHECKSUM_HW; 825 skb->csum = 0; 826 sk->sk_sndmsg_off = 0; 827 } 828 829 err = skb_append_datato_frags(sk,skb, getfrag, from, 830 (length - transhdrlen)); 831 if (!err) { 832 struct frag_hdr fhdr; 833 834 /* specify the length of each IP datagram fragment*/ 835 skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 836 sizeof(struct frag_hdr); 837 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 838 ipv6_select_ident(skb, &fhdr); 839 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 840 __skb_queue_tail(&sk->sk_write_queue, skb); 841 842 return 0; 843 } 844 /* There is not enough support do UPD LSO, 845 * so follow normal path 846 */ 847 kfree_skb(skb); 848 849 return err; 850 } 851 852 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 853 int offset, int len, int odd, struct sk_buff *skb), 854 void *from, int length, int transhdrlen, 855 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl, 856 struct rt6_info *rt, unsigned int flags) 857 { 858 struct inet_sock *inet = inet_sk(sk); 859 struct ipv6_pinfo *np = inet6_sk(sk); 860 struct sk_buff *skb; 861 unsigned int maxfraglen, fragheaderlen; 862 int exthdrlen; 863 int hh_len; 864 int mtu; 865 int copy; 866 int err; 867 int offset = 0; 868 int csummode = CHECKSUM_NONE; 869 870 if (flags&MSG_PROBE) 871 return 0; 872 if (skb_queue_empty(&sk->sk_write_queue)) { 873 /* 874 * setup for corking 875 */ 876 if (opt) { 877 if (np->cork.opt == NULL) { 878 np->cork.opt = kmalloc(opt->tot_len, 879 sk->sk_allocation); 880 if (unlikely(np->cork.opt == NULL)) 881 return -ENOBUFS; 882 } else if (np->cork.opt->tot_len < opt->tot_len) { 883 printk(KERN_DEBUG "ip6_append_data: invalid option length\n"); 884 return -EINVAL; 885 } 886 memcpy(np->cork.opt, opt, opt->tot_len); 887 inet->cork.flags |= IPCORK_OPT; 888 /* need source address above miyazawa*/ 889 } 890 dst_hold(&rt->u.dst); 891 np->cork.rt = rt; 892 inet->cork.fl = *fl; 893 np->cork.hop_limit = hlimit; 894 np->cork.tclass = tclass; 895 mtu = dst_mtu(rt->u.dst.path); 896 if (np->frag_size < mtu) { 897 if (np->frag_size) 898 mtu = np->frag_size; 899 } 900 inet->cork.fragsize = mtu; 901 if (dst_allfrag(rt->u.dst.path)) 902 inet->cork.flags |= IPCORK_ALLFRAG; 903 inet->cork.length = 0; 904 sk->sk_sndmsg_page = NULL; 905 sk->sk_sndmsg_off = 0; 906 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0); 907 length += exthdrlen; 908 transhdrlen += exthdrlen; 909 } else { 910 rt = np->cork.rt; 911 fl = &inet->cork.fl; 912 if (inet->cork.flags & IPCORK_OPT) 913 opt = np->cork.opt; 914 transhdrlen = 0; 915 exthdrlen = 0; 916 mtu = inet->cork.fragsize; 917 } 918 919 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 920 921 fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0); 922 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); 923 924 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 925 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { 926 ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen); 927 return -EMSGSIZE; 928 } 929 } 930 931 /* 932 * Let's try using as much space as possible. 933 * Use MTU if total length of the message fits into the MTU. 934 * Otherwise, we need to reserve fragment header and 935 * fragment alignment (= 8-15 octects, in total). 936 * 937 * Note that we may need to "move" the data from the tail of 938 * of the buffer to the new fragment when we split 939 * the message. 940 * 941 * FIXME: It may be fragmented into multiple chunks 942 * at once if non-fragmentable extension headers 943 * are too large. 944 * --yoshfuji 945 */ 946 947 inet->cork.length += length; 948 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 949 (rt->u.dst.dev->features & NETIF_F_UFO)) { 950 951 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, 952 fragheaderlen, transhdrlen, mtu, 953 flags); 954 if (err) 955 goto error; 956 return 0; 957 } 958 959 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 960 goto alloc_new_skb; 961 962 while (length > 0) { 963 /* Check if the remaining data fits into current packet. */ 964 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 965 if (copy < length) 966 copy = maxfraglen - skb->len; 967 968 if (copy <= 0) { 969 char *data; 970 unsigned int datalen; 971 unsigned int fraglen; 972 unsigned int fraggap; 973 unsigned int alloclen; 974 struct sk_buff *skb_prev; 975 alloc_new_skb: 976 skb_prev = skb; 977 978 /* There's no room in the current skb */ 979 if (skb_prev) 980 fraggap = skb_prev->len - maxfraglen; 981 else 982 fraggap = 0; 983 984 /* 985 * If remaining data exceeds the mtu, 986 * we know we need more fragment(s). 987 */ 988 datalen = length + fraggap; 989 if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 990 datalen = maxfraglen - fragheaderlen; 991 992 fraglen = datalen + fragheaderlen; 993 if ((flags & MSG_MORE) && 994 !(rt->u.dst.dev->features&NETIF_F_SG)) 995 alloclen = mtu; 996 else 997 alloclen = datalen + fragheaderlen; 998 999 /* 1000 * The last fragment gets additional space at tail. 1001 * Note: we overallocate on fragments with MSG_MODE 1002 * because we have no idea if we're the last one. 1003 */ 1004 if (datalen == length + fraggap) 1005 alloclen += rt->u.dst.trailer_len; 1006 1007 /* 1008 * We just reserve space for fragment header. 1009 * Note: this may be overallocation if the message 1010 * (without MSG_MORE) fits into the MTU. 1011 */ 1012 alloclen += sizeof(struct frag_hdr); 1013 1014 if (transhdrlen) { 1015 skb = sock_alloc_send_skb(sk, 1016 alloclen + hh_len, 1017 (flags & MSG_DONTWAIT), &err); 1018 } else { 1019 skb = NULL; 1020 if (atomic_read(&sk->sk_wmem_alloc) <= 1021 2 * sk->sk_sndbuf) 1022 skb = sock_wmalloc(sk, 1023 alloclen + hh_len, 1, 1024 sk->sk_allocation); 1025 if (unlikely(skb == NULL)) 1026 err = -ENOBUFS; 1027 } 1028 if (skb == NULL) 1029 goto error; 1030 /* 1031 * Fill in the control structures 1032 */ 1033 skb->ip_summed = csummode; 1034 skb->csum = 0; 1035 /* reserve for fragmentation */ 1036 skb_reserve(skb, hh_len+sizeof(struct frag_hdr)); 1037 1038 /* 1039 * Find where to start putting bytes 1040 */ 1041 data = skb_put(skb, fraglen); 1042 skb->nh.raw = data + exthdrlen; 1043 data += fragheaderlen; 1044 skb->h.raw = data + exthdrlen; 1045 1046 if (fraggap) { 1047 skb->csum = skb_copy_and_csum_bits( 1048 skb_prev, maxfraglen, 1049 data + transhdrlen, fraggap, 0); 1050 skb_prev->csum = csum_sub(skb_prev->csum, 1051 skb->csum); 1052 data += fraggap; 1053 skb_trim(skb_prev, maxfraglen); 1054 } 1055 copy = datalen - transhdrlen - fraggap; 1056 if (copy < 0) { 1057 err = -EINVAL; 1058 kfree_skb(skb); 1059 goto error; 1060 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1061 err = -EFAULT; 1062 kfree_skb(skb); 1063 goto error; 1064 } 1065 1066 offset += copy; 1067 length -= datalen - fraggap; 1068 transhdrlen = 0; 1069 exthdrlen = 0; 1070 csummode = CHECKSUM_NONE; 1071 1072 /* 1073 * Put the packet on the pending queue 1074 */ 1075 __skb_queue_tail(&sk->sk_write_queue, skb); 1076 continue; 1077 } 1078 1079 if (copy > length) 1080 copy = length; 1081 1082 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 1083 unsigned int off; 1084 1085 off = skb->len; 1086 if (getfrag(from, skb_put(skb, copy), 1087 offset, copy, off, skb) < 0) { 1088 __skb_trim(skb, off); 1089 err = -EFAULT; 1090 goto error; 1091 } 1092 } else { 1093 int i = skb_shinfo(skb)->nr_frags; 1094 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1095 struct page *page = sk->sk_sndmsg_page; 1096 int off = sk->sk_sndmsg_off; 1097 unsigned int left; 1098 1099 if (page && (left = PAGE_SIZE - off) > 0) { 1100 if (copy >= left) 1101 copy = left; 1102 if (page != frag->page) { 1103 if (i == MAX_SKB_FRAGS) { 1104 err = -EMSGSIZE; 1105 goto error; 1106 } 1107 get_page(page); 1108 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1109 frag = &skb_shinfo(skb)->frags[i]; 1110 } 1111 } else if(i < MAX_SKB_FRAGS) { 1112 if (copy > PAGE_SIZE) 1113 copy = PAGE_SIZE; 1114 page = alloc_pages(sk->sk_allocation, 0); 1115 if (page == NULL) { 1116 err = -ENOMEM; 1117 goto error; 1118 } 1119 sk->sk_sndmsg_page = page; 1120 sk->sk_sndmsg_off = 0; 1121 1122 skb_fill_page_desc(skb, i, page, 0, 0); 1123 frag = &skb_shinfo(skb)->frags[i]; 1124 skb->truesize += PAGE_SIZE; 1125 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1126 } else { 1127 err = -EMSGSIZE; 1128 goto error; 1129 } 1130 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1131 err = -EFAULT; 1132 goto error; 1133 } 1134 sk->sk_sndmsg_off += copy; 1135 frag->size += copy; 1136 skb->len += copy; 1137 skb->data_len += copy; 1138 } 1139 offset += copy; 1140 length -= copy; 1141 } 1142 return 0; 1143 error: 1144 inet->cork.length -= length; 1145 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1146 return err; 1147 } 1148 1149 int ip6_push_pending_frames(struct sock *sk) 1150 { 1151 struct sk_buff *skb, *tmp_skb; 1152 struct sk_buff **tail_skb; 1153 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1154 struct inet_sock *inet = inet_sk(sk); 1155 struct ipv6_pinfo *np = inet6_sk(sk); 1156 struct ipv6hdr *hdr; 1157 struct ipv6_txoptions *opt = np->cork.opt; 1158 struct rt6_info *rt = np->cork.rt; 1159 struct flowi *fl = &inet->cork.fl; 1160 unsigned char proto = fl->proto; 1161 int err = 0; 1162 1163 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1164 goto out; 1165 tail_skb = &(skb_shinfo(skb)->frag_list); 1166 1167 /* move skb->data to ip header from ext header */ 1168 if (skb->data < skb->nh.raw) 1169 __skb_pull(skb, skb->nh.raw - skb->data); 1170 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1171 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1172 *tail_skb = tmp_skb; 1173 tail_skb = &(tmp_skb->next); 1174 skb->len += tmp_skb->len; 1175 skb->data_len += tmp_skb->len; 1176 skb->truesize += tmp_skb->truesize; 1177 __sock_put(tmp_skb->sk); 1178 tmp_skb->destructor = NULL; 1179 tmp_skb->sk = NULL; 1180 } 1181 1182 ipv6_addr_copy(final_dst, &fl->fl6_dst); 1183 __skb_pull(skb, skb->h.raw - skb->nh.raw); 1184 if (opt && opt->opt_flen) 1185 ipv6_push_frag_opts(skb, opt, &proto); 1186 if (opt && opt->opt_nflen) 1187 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1188 1189 skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr)); 1190 1191 *(u32*)hdr = fl->fl6_flowlabel | 1192 htonl(0x60000000 | ((int)np->cork.tclass << 20)); 1193 1194 if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) 1195 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 1196 else 1197 hdr->payload_len = 0; 1198 hdr->hop_limit = np->cork.hop_limit; 1199 hdr->nexthdr = proto; 1200 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 1201 ipv6_addr_copy(&hdr->daddr, final_dst); 1202 1203 skb->priority = sk->sk_priority; 1204 1205 skb->dst = dst_clone(&rt->u.dst); 1206 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 1207 err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output); 1208 if (err) { 1209 if (err > 0) 1210 err = np->recverr ? net_xmit_errno(err) : 0; 1211 if (err) 1212 goto error; 1213 } 1214 1215 out: 1216 inet->cork.flags &= ~IPCORK_OPT; 1217 kfree(np->cork.opt); 1218 np->cork.opt = NULL; 1219 if (np->cork.rt) { 1220 dst_release(&np->cork.rt->u.dst); 1221 np->cork.rt = NULL; 1222 inet->cork.flags &= ~IPCORK_ALLFRAG; 1223 } 1224 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1225 return err; 1226 error: 1227 goto out; 1228 } 1229 1230 void ip6_flush_pending_frames(struct sock *sk) 1231 { 1232 struct inet_sock *inet = inet_sk(sk); 1233 struct ipv6_pinfo *np = inet6_sk(sk); 1234 struct sk_buff *skb; 1235 1236 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1237 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1238 kfree_skb(skb); 1239 } 1240 1241 inet->cork.flags &= ~IPCORK_OPT; 1242 1243 kfree(np->cork.opt); 1244 np->cork.opt = NULL; 1245 if (np->cork.rt) { 1246 dst_release(&np->cork.rt->u.dst); 1247 np->cork.rt = NULL; 1248 inet->cork.flags &= ~IPCORK_ALLFRAG; 1249 } 1250 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1251 } 1252