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/config.h> 32 #include <linux/errno.h> 33 #include <linux/types.h> 34 #include <linux/string.h> 35 #include <linux/socket.h> 36 #include <linux/net.h> 37 #include <linux/netdevice.h> 38 #include <linux/if_arp.h> 39 #include <linux/in6.h> 40 #include <linux/tcp.h> 41 #include <linux/route.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_shinfo(skb)->ufo_size) || 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) { 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 } 462 463 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 464 { 465 u16 offset = sizeof(struct ipv6hdr); 466 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); 467 unsigned int packet_len = skb->tail - skb->nh.raw; 468 int found_rhdr = 0; 469 *nexthdr = &skb->nh.ipv6h->nexthdr; 470 471 while (offset + 1 <= packet_len) { 472 473 switch (**nexthdr) { 474 475 case NEXTHDR_HOP: 476 case NEXTHDR_ROUTING: 477 case NEXTHDR_DEST: 478 if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1; 479 if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset; 480 offset += ipv6_optlen(exthdr); 481 *nexthdr = &exthdr->nexthdr; 482 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); 483 break; 484 default : 485 return offset; 486 } 487 } 488 489 return offset; 490 } 491 492 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 493 { 494 struct net_device *dev; 495 struct sk_buff *frag; 496 struct rt6_info *rt = (struct rt6_info*)skb->dst; 497 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 498 struct ipv6hdr *tmp_hdr; 499 struct frag_hdr *fh; 500 unsigned int mtu, hlen, left, len; 501 u32 frag_id = 0; 502 int ptr, offset = 0, err=0; 503 u8 *prevhdr, nexthdr = 0; 504 505 dev = rt->u.dst.dev; 506 hlen = ip6_find_1stfragopt(skb, &prevhdr); 507 nexthdr = *prevhdr; 508 509 mtu = dst_mtu(&rt->u.dst); 510 if (np && np->frag_size < mtu) { 511 if (np->frag_size) 512 mtu = np->frag_size; 513 } 514 mtu -= hlen + sizeof(struct frag_hdr); 515 516 if (skb_shinfo(skb)->frag_list) { 517 int first_len = skb_pagelen(skb); 518 519 if (first_len - hlen > mtu || 520 ((first_len - hlen) & 7) || 521 skb_cloned(skb)) 522 goto slow_path; 523 524 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 525 /* Correct geometry. */ 526 if (frag->len > mtu || 527 ((frag->len & 7) && frag->next) || 528 skb_headroom(frag) < hlen) 529 goto slow_path; 530 531 /* Partially cloned skb? */ 532 if (skb_shared(frag)) 533 goto slow_path; 534 535 BUG_ON(frag->sk); 536 if (skb->sk) { 537 sock_hold(skb->sk); 538 frag->sk = skb->sk; 539 frag->destructor = sock_wfree; 540 skb->truesize -= frag->truesize; 541 } 542 } 543 544 err = 0; 545 offset = 0; 546 frag = skb_shinfo(skb)->frag_list; 547 skb_shinfo(skb)->frag_list = NULL; 548 /* BUILD HEADER */ 549 550 tmp_hdr = kmalloc(hlen, GFP_ATOMIC); 551 if (!tmp_hdr) { 552 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 553 return -ENOMEM; 554 } 555 556 *prevhdr = NEXTHDR_FRAGMENT; 557 memcpy(tmp_hdr, skb->nh.raw, hlen); 558 __skb_pull(skb, hlen); 559 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 560 skb->nh.raw = __skb_push(skb, hlen); 561 memcpy(skb->nh.raw, tmp_hdr, hlen); 562 563 ipv6_select_ident(skb, fh); 564 fh->nexthdr = nexthdr; 565 fh->reserved = 0; 566 fh->frag_off = htons(IP6_MF); 567 frag_id = fh->identification; 568 569 first_len = skb_pagelen(skb); 570 skb->data_len = first_len - skb_headlen(skb); 571 skb->len = first_len; 572 skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr)); 573 574 575 for (;;) { 576 /* Prepare header of the next frame, 577 * before previous one went down. */ 578 if (frag) { 579 frag->ip_summed = CHECKSUM_NONE; 580 frag->h.raw = frag->data; 581 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 582 frag->nh.raw = __skb_push(frag, hlen); 583 memcpy(frag->nh.raw, tmp_hdr, hlen); 584 offset += skb->len - hlen - sizeof(struct frag_hdr); 585 fh->nexthdr = nexthdr; 586 fh->reserved = 0; 587 fh->frag_off = htons(offset); 588 if (frag->next != NULL) 589 fh->frag_off |= htons(IP6_MF); 590 fh->identification = frag_id; 591 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 592 ip6_copy_metadata(frag, skb); 593 } 594 595 err = output(skb); 596 if (err || !frag) 597 break; 598 599 skb = frag; 600 frag = skb->next; 601 skb->next = NULL; 602 } 603 604 kfree(tmp_hdr); 605 606 if (err == 0) { 607 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 608 return 0; 609 } 610 611 while (frag) { 612 skb = frag->next; 613 kfree_skb(frag); 614 frag = skb; 615 } 616 617 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 618 return err; 619 } 620 621 slow_path: 622 left = skb->len - hlen; /* Space per frame */ 623 ptr = hlen; /* Where to start from */ 624 625 /* 626 * Fragment the datagram. 627 */ 628 629 *prevhdr = NEXTHDR_FRAGMENT; 630 631 /* 632 * Keep copying data until we run out. 633 */ 634 while(left > 0) { 635 len = left; 636 /* IF: it doesn't fit, use 'mtu' - the data space left */ 637 if (len > mtu) 638 len = mtu; 639 /* IF: we are not sending upto and including the packet end 640 then align the next start on an eight byte boundary */ 641 if (len < left) { 642 len &= ~7; 643 } 644 /* 645 * Allocate buffer. 646 */ 647 648 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { 649 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 650 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 651 err = -ENOMEM; 652 goto fail; 653 } 654 655 /* 656 * Set up data on packet 657 */ 658 659 ip6_copy_metadata(frag, skb); 660 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev)); 661 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 662 frag->nh.raw = frag->data; 663 fh = (struct frag_hdr*)(frag->data + hlen); 664 frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr); 665 666 /* 667 * Charge the memory for the fragment to any owner 668 * it might possess 669 */ 670 if (skb->sk) 671 skb_set_owner_w(frag, skb->sk); 672 673 /* 674 * Copy the packet header into the new buffer. 675 */ 676 memcpy(frag->nh.raw, skb->data, hlen); 677 678 /* 679 * Build fragment header. 680 */ 681 fh->nexthdr = nexthdr; 682 fh->reserved = 0; 683 if (!frag_id) { 684 ipv6_select_ident(skb, fh); 685 frag_id = fh->identification; 686 } else 687 fh->identification = frag_id; 688 689 /* 690 * Copy a block of the IP datagram. 691 */ 692 if (skb_copy_bits(skb, ptr, frag->h.raw, len)) 693 BUG(); 694 left -= len; 695 696 fh->frag_off = htons(offset); 697 if (left > 0) 698 fh->frag_off |= htons(IP6_MF); 699 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 700 701 ptr += len; 702 offset += len; 703 704 /* 705 * Put this fragment into the sending queue. 706 */ 707 708 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES); 709 710 err = output(frag); 711 if (err) 712 goto fail; 713 } 714 kfree_skb(skb); 715 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 716 return err; 717 718 fail: 719 kfree_skb(skb); 720 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 721 return err; 722 } 723 724 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) 725 { 726 int err = 0; 727 728 *dst = NULL; 729 if (sk) { 730 struct ipv6_pinfo *np = inet6_sk(sk); 731 732 *dst = sk_dst_check(sk, np->dst_cookie); 733 if (*dst) { 734 struct rt6_info *rt = (struct rt6_info*)*dst; 735 736 /* Yes, checking route validity in not connected 737 * case is not very simple. Take into account, 738 * that we do not support routing by source, TOS, 739 * and MSG_DONTROUTE --ANK (980726) 740 * 741 * 1. If route was host route, check that 742 * cached destination is current. 743 * If it is network route, we still may 744 * check its validity using saved pointer 745 * to the last used address: daddr_cache. 746 * We do not want to save whole address now, 747 * (because main consumer of this service 748 * is tcp, which has not this problem), 749 * so that the last trick works only on connected 750 * sockets. 751 * 2. oif also should be the same. 752 */ 753 if (((rt->rt6i_dst.plen != 128 || 754 !ipv6_addr_equal(&fl->fl6_dst, 755 &rt->rt6i_dst.addr)) 756 && (np->daddr_cache == NULL || 757 !ipv6_addr_equal(&fl->fl6_dst, 758 np->daddr_cache))) 759 || (fl->oif && fl->oif != (*dst)->dev->ifindex)) { 760 dst_release(*dst); 761 *dst = NULL; 762 } 763 } 764 } 765 766 if (*dst == NULL) 767 *dst = ip6_route_output(sk, fl); 768 769 if ((err = (*dst)->error)) 770 goto out_err_release; 771 772 if (ipv6_addr_any(&fl->fl6_src)) { 773 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src); 774 775 if (err) 776 goto out_err_release; 777 } 778 779 return 0; 780 781 out_err_release: 782 dst_release(*dst); 783 *dst = NULL; 784 return err; 785 } 786 787 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 788 789 static inline int ip6_ufo_append_data(struct sock *sk, 790 int getfrag(void *from, char *to, int offset, int len, 791 int odd, struct sk_buff *skb), 792 void *from, int length, int hh_len, int fragheaderlen, 793 int transhdrlen, int mtu,unsigned int flags) 794 795 { 796 struct sk_buff *skb; 797 int err; 798 799 /* There is support for UDP large send offload by network 800 * device, so create one single skb packet containing complete 801 * udp datagram 802 */ 803 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 804 skb = sock_alloc_send_skb(sk, 805 hh_len + fragheaderlen + transhdrlen + 20, 806 (flags & MSG_DONTWAIT), &err); 807 if (skb == NULL) 808 return -ENOMEM; 809 810 /* reserve space for Hardware header */ 811 skb_reserve(skb, hh_len); 812 813 /* create space for UDP/IP header */ 814 skb_put(skb,fragheaderlen + transhdrlen); 815 816 /* initialize network header pointer */ 817 skb->nh.raw = skb->data; 818 819 /* initialize protocol header pointer */ 820 skb->h.raw = skb->data + fragheaderlen; 821 822 skb->ip_summed = CHECKSUM_HW; 823 skb->csum = 0; 824 sk->sk_sndmsg_off = 0; 825 } 826 827 err = skb_append_datato_frags(sk,skb, getfrag, from, 828 (length - transhdrlen)); 829 if (!err) { 830 struct frag_hdr fhdr; 831 832 /* specify the length of each IP datagram fragment*/ 833 skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen) - 834 sizeof(struct frag_hdr); 835 ipv6_select_ident(skb, &fhdr); 836 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 837 __skb_queue_tail(&sk->sk_write_queue, skb); 838 839 return 0; 840 } 841 /* There is not enough support do UPD LSO, 842 * so follow normal path 843 */ 844 kfree_skb(skb); 845 846 return err; 847 } 848 849 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 850 int offset, int len, int odd, struct sk_buff *skb), 851 void *from, int length, int transhdrlen, 852 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl, 853 struct rt6_info *rt, unsigned int flags) 854 { 855 struct inet_sock *inet = inet_sk(sk); 856 struct ipv6_pinfo *np = inet6_sk(sk); 857 struct sk_buff *skb; 858 unsigned int maxfraglen, fragheaderlen; 859 int exthdrlen; 860 int hh_len; 861 int mtu; 862 int copy; 863 int err; 864 int offset = 0; 865 int csummode = CHECKSUM_NONE; 866 867 if (flags&MSG_PROBE) 868 return 0; 869 if (skb_queue_empty(&sk->sk_write_queue)) { 870 /* 871 * setup for corking 872 */ 873 if (opt) { 874 if (np->cork.opt == NULL) { 875 np->cork.opt = kmalloc(opt->tot_len, 876 sk->sk_allocation); 877 if (unlikely(np->cork.opt == NULL)) 878 return -ENOBUFS; 879 } else if (np->cork.opt->tot_len < opt->tot_len) { 880 printk(KERN_DEBUG "ip6_append_data: invalid option length\n"); 881 return -EINVAL; 882 } 883 memcpy(np->cork.opt, opt, opt->tot_len); 884 inet->cork.flags |= IPCORK_OPT; 885 /* need source address above miyazawa*/ 886 } 887 dst_hold(&rt->u.dst); 888 np->cork.rt = rt; 889 inet->cork.fl = *fl; 890 np->cork.hop_limit = hlimit; 891 np->cork.tclass = tclass; 892 mtu = dst_mtu(rt->u.dst.path); 893 if (np->frag_size < mtu) { 894 if (np->frag_size) 895 mtu = np->frag_size; 896 } 897 inet->cork.fragsize = mtu; 898 if (dst_allfrag(rt->u.dst.path)) 899 inet->cork.flags |= IPCORK_ALLFRAG; 900 inet->cork.length = 0; 901 sk->sk_sndmsg_page = NULL; 902 sk->sk_sndmsg_off = 0; 903 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0); 904 length += exthdrlen; 905 transhdrlen += exthdrlen; 906 } else { 907 rt = np->cork.rt; 908 fl = &inet->cork.fl; 909 if (inet->cork.flags & IPCORK_OPT) 910 opt = np->cork.opt; 911 transhdrlen = 0; 912 exthdrlen = 0; 913 mtu = inet->cork.fragsize; 914 } 915 916 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 917 918 fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0); 919 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); 920 921 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 922 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { 923 ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen); 924 return -EMSGSIZE; 925 } 926 } 927 928 /* 929 * Let's try using as much space as possible. 930 * Use MTU if total length of the message fits into the MTU. 931 * Otherwise, we need to reserve fragment header and 932 * fragment alignment (= 8-15 octects, in total). 933 * 934 * Note that we may need to "move" the data from the tail of 935 * of the buffer to the new fragment when we split 936 * the message. 937 * 938 * FIXME: It may be fragmented into multiple chunks 939 * at once if non-fragmentable extension headers 940 * are too large. 941 * --yoshfuji 942 */ 943 944 inet->cork.length += length; 945 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 946 (rt->u.dst.dev->features & NETIF_F_UFO)) { 947 948 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, 949 fragheaderlen, transhdrlen, mtu, 950 flags); 951 if (err) 952 goto error; 953 return 0; 954 } 955 956 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 957 goto alloc_new_skb; 958 959 while (length > 0) { 960 /* Check if the remaining data fits into current packet. */ 961 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 962 if (copy < length) 963 copy = maxfraglen - skb->len; 964 965 if (copy <= 0) { 966 char *data; 967 unsigned int datalen; 968 unsigned int fraglen; 969 unsigned int fraggap; 970 unsigned int alloclen; 971 struct sk_buff *skb_prev; 972 alloc_new_skb: 973 skb_prev = skb; 974 975 /* There's no room in the current skb */ 976 if (skb_prev) 977 fraggap = skb_prev->len - maxfraglen; 978 else 979 fraggap = 0; 980 981 /* 982 * If remaining data exceeds the mtu, 983 * we know we need more fragment(s). 984 */ 985 datalen = length + fraggap; 986 if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 987 datalen = maxfraglen - fragheaderlen; 988 989 fraglen = datalen + fragheaderlen; 990 if ((flags & MSG_MORE) && 991 !(rt->u.dst.dev->features&NETIF_F_SG)) 992 alloclen = mtu; 993 else 994 alloclen = datalen + fragheaderlen; 995 996 /* 997 * The last fragment gets additional space at tail. 998 * Note: we overallocate on fragments with MSG_MODE 999 * because we have no idea if we're the last one. 1000 */ 1001 if (datalen == length + fraggap) 1002 alloclen += rt->u.dst.trailer_len; 1003 1004 /* 1005 * We just reserve space for fragment header. 1006 * Note: this may be overallocation if the message 1007 * (without MSG_MORE) fits into the MTU. 1008 */ 1009 alloclen += sizeof(struct frag_hdr); 1010 1011 if (transhdrlen) { 1012 skb = sock_alloc_send_skb(sk, 1013 alloclen + hh_len, 1014 (flags & MSG_DONTWAIT), &err); 1015 } else { 1016 skb = NULL; 1017 if (atomic_read(&sk->sk_wmem_alloc) <= 1018 2 * sk->sk_sndbuf) 1019 skb = sock_wmalloc(sk, 1020 alloclen + hh_len, 1, 1021 sk->sk_allocation); 1022 if (unlikely(skb == NULL)) 1023 err = -ENOBUFS; 1024 } 1025 if (skb == NULL) 1026 goto error; 1027 /* 1028 * Fill in the control structures 1029 */ 1030 skb->ip_summed = csummode; 1031 skb->csum = 0; 1032 /* reserve for fragmentation */ 1033 skb_reserve(skb, hh_len+sizeof(struct frag_hdr)); 1034 1035 /* 1036 * Find where to start putting bytes 1037 */ 1038 data = skb_put(skb, fraglen); 1039 skb->nh.raw = data + exthdrlen; 1040 data += fragheaderlen; 1041 skb->h.raw = data + exthdrlen; 1042 1043 if (fraggap) { 1044 skb->csum = skb_copy_and_csum_bits( 1045 skb_prev, maxfraglen, 1046 data + transhdrlen, fraggap, 0); 1047 skb_prev->csum = csum_sub(skb_prev->csum, 1048 skb->csum); 1049 data += fraggap; 1050 skb_trim(skb_prev, maxfraglen); 1051 } 1052 copy = datalen - transhdrlen - fraggap; 1053 if (copy < 0) { 1054 err = -EINVAL; 1055 kfree_skb(skb); 1056 goto error; 1057 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1058 err = -EFAULT; 1059 kfree_skb(skb); 1060 goto error; 1061 } 1062 1063 offset += copy; 1064 length -= datalen - fraggap; 1065 transhdrlen = 0; 1066 exthdrlen = 0; 1067 csummode = CHECKSUM_NONE; 1068 1069 /* 1070 * Put the packet on the pending queue 1071 */ 1072 __skb_queue_tail(&sk->sk_write_queue, skb); 1073 continue; 1074 } 1075 1076 if (copy > length) 1077 copy = length; 1078 1079 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 1080 unsigned int off; 1081 1082 off = skb->len; 1083 if (getfrag(from, skb_put(skb, copy), 1084 offset, copy, off, skb) < 0) { 1085 __skb_trim(skb, off); 1086 err = -EFAULT; 1087 goto error; 1088 } 1089 } else { 1090 int i = skb_shinfo(skb)->nr_frags; 1091 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1092 struct page *page = sk->sk_sndmsg_page; 1093 int off = sk->sk_sndmsg_off; 1094 unsigned int left; 1095 1096 if (page && (left = PAGE_SIZE - off) > 0) { 1097 if (copy >= left) 1098 copy = left; 1099 if (page != frag->page) { 1100 if (i == MAX_SKB_FRAGS) { 1101 err = -EMSGSIZE; 1102 goto error; 1103 } 1104 get_page(page); 1105 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1106 frag = &skb_shinfo(skb)->frags[i]; 1107 } 1108 } else if(i < MAX_SKB_FRAGS) { 1109 if (copy > PAGE_SIZE) 1110 copy = PAGE_SIZE; 1111 page = alloc_pages(sk->sk_allocation, 0); 1112 if (page == NULL) { 1113 err = -ENOMEM; 1114 goto error; 1115 } 1116 sk->sk_sndmsg_page = page; 1117 sk->sk_sndmsg_off = 0; 1118 1119 skb_fill_page_desc(skb, i, page, 0, 0); 1120 frag = &skb_shinfo(skb)->frags[i]; 1121 skb->truesize += PAGE_SIZE; 1122 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1123 } else { 1124 err = -EMSGSIZE; 1125 goto error; 1126 } 1127 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1128 err = -EFAULT; 1129 goto error; 1130 } 1131 sk->sk_sndmsg_off += copy; 1132 frag->size += copy; 1133 skb->len += copy; 1134 skb->data_len += copy; 1135 } 1136 offset += copy; 1137 length -= copy; 1138 } 1139 return 0; 1140 error: 1141 inet->cork.length -= length; 1142 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1143 return err; 1144 } 1145 1146 int ip6_push_pending_frames(struct sock *sk) 1147 { 1148 struct sk_buff *skb, *tmp_skb; 1149 struct sk_buff **tail_skb; 1150 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1151 struct inet_sock *inet = inet_sk(sk); 1152 struct ipv6_pinfo *np = inet6_sk(sk); 1153 struct ipv6hdr *hdr; 1154 struct ipv6_txoptions *opt = np->cork.opt; 1155 struct rt6_info *rt = np->cork.rt; 1156 struct flowi *fl = &inet->cork.fl; 1157 unsigned char proto = fl->proto; 1158 int err = 0; 1159 1160 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1161 goto out; 1162 tail_skb = &(skb_shinfo(skb)->frag_list); 1163 1164 /* move skb->data to ip header from ext header */ 1165 if (skb->data < skb->nh.raw) 1166 __skb_pull(skb, skb->nh.raw - skb->data); 1167 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1168 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1169 *tail_skb = tmp_skb; 1170 tail_skb = &(tmp_skb->next); 1171 skb->len += tmp_skb->len; 1172 skb->data_len += tmp_skb->len; 1173 skb->truesize += tmp_skb->truesize; 1174 __sock_put(tmp_skb->sk); 1175 tmp_skb->destructor = NULL; 1176 tmp_skb->sk = NULL; 1177 } 1178 1179 ipv6_addr_copy(final_dst, &fl->fl6_dst); 1180 __skb_pull(skb, skb->h.raw - skb->nh.raw); 1181 if (opt && opt->opt_flen) 1182 ipv6_push_frag_opts(skb, opt, &proto); 1183 if (opt && opt->opt_nflen) 1184 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1185 1186 skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr)); 1187 1188 *(u32*)hdr = fl->fl6_flowlabel | 1189 htonl(0x60000000 | ((int)np->cork.tclass << 20)); 1190 1191 if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) 1192 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 1193 else 1194 hdr->payload_len = 0; 1195 hdr->hop_limit = np->cork.hop_limit; 1196 hdr->nexthdr = proto; 1197 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 1198 ipv6_addr_copy(&hdr->daddr, final_dst); 1199 1200 skb->priority = sk->sk_priority; 1201 1202 skb->dst = dst_clone(&rt->u.dst); 1203 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 1204 err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output); 1205 if (err) { 1206 if (err > 0) 1207 err = np->recverr ? net_xmit_errno(err) : 0; 1208 if (err) 1209 goto error; 1210 } 1211 1212 out: 1213 inet->cork.flags &= ~IPCORK_OPT; 1214 kfree(np->cork.opt); 1215 np->cork.opt = NULL; 1216 if (np->cork.rt) { 1217 dst_release(&np->cork.rt->u.dst); 1218 np->cork.rt = NULL; 1219 inet->cork.flags &= ~IPCORK_ALLFRAG; 1220 } 1221 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1222 return err; 1223 error: 1224 goto out; 1225 } 1226 1227 void ip6_flush_pending_frames(struct sock *sk) 1228 { 1229 struct inet_sock *inet = inet_sk(sk); 1230 struct ipv6_pinfo *np = inet6_sk(sk); 1231 struct sk_buff *skb; 1232 1233 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1234 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1235 kfree_skb(skb); 1236 } 1237 1238 inet->cork.flags &= ~IPCORK_OPT; 1239 1240 kfree(np->cork.opt); 1241 np->cork.opt = NULL; 1242 if (np->cork.rt) { 1243 dst_release(&np->cork.rt->u.dst); 1244 np->cork.rt = NULL; 1245 inet->cork.flags &= ~IPCORK_ALLFRAG; 1246 } 1247 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1248 } 1249