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 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 360 361 kfree_skb(skb); 362 return -ETIMEDOUT; 363 } 364 365 if (!xfrm6_route_forward(skb)) { 366 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS); 367 goto drop; 368 } 369 dst = skb->dst; 370 371 /* IPv6 specs say nothing about it, but it is clear that we cannot 372 send redirects to source routed frames. 373 */ 374 if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) { 375 struct in6_addr *target = NULL; 376 struct rt6_info *rt; 377 struct neighbour *n = dst->neighbour; 378 379 /* 380 * incoming and outgoing devices are the same 381 * send a redirect. 382 */ 383 384 rt = (struct rt6_info *) dst; 385 if ((rt->rt6i_flags & RTF_GATEWAY)) 386 target = (struct in6_addr*)&n->primary_key; 387 else 388 target = &hdr->daddr; 389 390 /* Limit redirects both by destination (here) 391 and by source (inside ndisc_send_redirect) 392 */ 393 if (xrlim_allow(dst, 1*HZ)) 394 ndisc_send_redirect(skb, n, target); 395 } else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK 396 |IPV6_ADDR_LINKLOCAL)) { 397 /* This check is security critical. */ 398 goto error; 399 } 400 401 if (skb->len > dst_mtu(dst)) { 402 /* Again, force OUTPUT device used as source address */ 403 skb->dev = dst->dev; 404 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev); 405 IP6_INC_STATS_BH(IPSTATS_MIB_INTOOBIGERRORS); 406 IP6_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS); 407 kfree_skb(skb); 408 return -EMSGSIZE; 409 } 410 411 if (skb_cow(skb, dst->dev->hard_header_len)) { 412 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 413 goto drop; 414 } 415 416 hdr = skb->nh.ipv6h; 417 418 /* Mangling hops number delayed to point after skb COW */ 419 420 hdr->hop_limit--; 421 422 IP6_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS); 423 return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish); 424 425 error: 426 IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS); 427 drop: 428 kfree_skb(skb); 429 return -EINVAL; 430 } 431 432 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) 433 { 434 to->pkt_type = from->pkt_type; 435 to->priority = from->priority; 436 to->protocol = from->protocol; 437 dst_release(to->dst); 438 to->dst = dst_clone(from->dst); 439 to->dev = from->dev; 440 441 #ifdef CONFIG_NET_SCHED 442 to->tc_index = from->tc_index; 443 #endif 444 #ifdef CONFIG_NETFILTER 445 to->nfmark = from->nfmark; 446 /* Connection association is same as pre-frag packet */ 447 nf_conntrack_put(to->nfct); 448 to->nfct = from->nfct; 449 nf_conntrack_get(to->nfct); 450 to->nfctinfo = from->nfctinfo; 451 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 452 nf_conntrack_put_reasm(to->nfct_reasm); 453 to->nfct_reasm = from->nfct_reasm; 454 nf_conntrack_get_reasm(to->nfct_reasm); 455 #endif 456 #ifdef CONFIG_BRIDGE_NETFILTER 457 nf_bridge_put(to->nf_bridge); 458 to->nf_bridge = from->nf_bridge; 459 nf_bridge_get(to->nf_bridge); 460 #endif 461 #endif 462 skb_copy_secmark(to, from); 463 } 464 465 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 466 { 467 u16 offset = sizeof(struct ipv6hdr); 468 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); 469 unsigned int packet_len = skb->tail - skb->nh.raw; 470 int found_rhdr = 0; 471 *nexthdr = &skb->nh.ipv6h->nexthdr; 472 473 while (offset + 1 <= packet_len) { 474 475 switch (**nexthdr) { 476 477 case NEXTHDR_HOP: 478 case NEXTHDR_ROUTING: 479 case NEXTHDR_DEST: 480 if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1; 481 if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset; 482 offset += ipv6_optlen(exthdr); 483 *nexthdr = &exthdr->nexthdr; 484 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); 485 break; 486 default : 487 return offset; 488 } 489 } 490 491 return offset; 492 } 493 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt); 494 495 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) 496 { 497 struct net_device *dev; 498 struct sk_buff *frag; 499 struct rt6_info *rt = (struct rt6_info*)skb->dst; 500 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; 501 struct ipv6hdr *tmp_hdr; 502 struct frag_hdr *fh; 503 unsigned int mtu, hlen, left, len; 504 u32 frag_id = 0; 505 int ptr, offset = 0, err=0; 506 u8 *prevhdr, nexthdr = 0; 507 508 dev = rt->u.dst.dev; 509 hlen = ip6_find_1stfragopt(skb, &prevhdr); 510 nexthdr = *prevhdr; 511 512 mtu = dst_mtu(&rt->u.dst); 513 if (np && np->frag_size < mtu) { 514 if (np->frag_size) 515 mtu = np->frag_size; 516 } 517 mtu -= hlen + sizeof(struct frag_hdr); 518 519 if (skb_shinfo(skb)->frag_list) { 520 int first_len = skb_pagelen(skb); 521 522 if (first_len - hlen > mtu || 523 ((first_len - hlen) & 7) || 524 skb_cloned(skb)) 525 goto slow_path; 526 527 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 528 /* Correct geometry. */ 529 if (frag->len > mtu || 530 ((frag->len & 7) && frag->next) || 531 skb_headroom(frag) < hlen) 532 goto slow_path; 533 534 /* Partially cloned skb? */ 535 if (skb_shared(frag)) 536 goto slow_path; 537 538 BUG_ON(frag->sk); 539 if (skb->sk) { 540 sock_hold(skb->sk); 541 frag->sk = skb->sk; 542 frag->destructor = sock_wfree; 543 skb->truesize -= frag->truesize; 544 } 545 } 546 547 err = 0; 548 offset = 0; 549 frag = skb_shinfo(skb)->frag_list; 550 skb_shinfo(skb)->frag_list = NULL; 551 /* BUILD HEADER */ 552 553 tmp_hdr = kmalloc(hlen, GFP_ATOMIC); 554 if (!tmp_hdr) { 555 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 556 return -ENOMEM; 557 } 558 559 *prevhdr = NEXTHDR_FRAGMENT; 560 memcpy(tmp_hdr, skb->nh.raw, hlen); 561 __skb_pull(skb, hlen); 562 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); 563 skb->nh.raw = __skb_push(skb, hlen); 564 memcpy(skb->nh.raw, tmp_hdr, hlen); 565 566 ipv6_select_ident(skb, fh); 567 fh->nexthdr = nexthdr; 568 fh->reserved = 0; 569 fh->frag_off = htons(IP6_MF); 570 frag_id = fh->identification; 571 572 first_len = skb_pagelen(skb); 573 skb->data_len = first_len - skb_headlen(skb); 574 skb->len = first_len; 575 skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr)); 576 577 578 for (;;) { 579 /* Prepare header of the next frame, 580 * before previous one went down. */ 581 if (frag) { 582 frag->ip_summed = CHECKSUM_NONE; 583 frag->h.raw = frag->data; 584 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); 585 frag->nh.raw = __skb_push(frag, hlen); 586 memcpy(frag->nh.raw, tmp_hdr, hlen); 587 offset += skb->len - hlen - sizeof(struct frag_hdr); 588 fh->nexthdr = nexthdr; 589 fh->reserved = 0; 590 fh->frag_off = htons(offset); 591 if (frag->next != NULL) 592 fh->frag_off |= htons(IP6_MF); 593 fh->identification = frag_id; 594 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 595 ip6_copy_metadata(frag, skb); 596 } 597 598 err = output(skb); 599 if(!err) 600 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES); 601 602 if (err || !frag) 603 break; 604 605 skb = frag; 606 frag = skb->next; 607 skb->next = NULL; 608 } 609 610 kfree(tmp_hdr); 611 612 if (err == 0) { 613 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 614 return 0; 615 } 616 617 while (frag) { 618 skb = frag->next; 619 kfree_skb(frag); 620 frag = skb; 621 } 622 623 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 624 return err; 625 } 626 627 slow_path: 628 left = skb->len - hlen; /* Space per frame */ 629 ptr = hlen; /* Where to start from */ 630 631 /* 632 * Fragment the datagram. 633 */ 634 635 *prevhdr = NEXTHDR_FRAGMENT; 636 637 /* 638 * Keep copying data until we run out. 639 */ 640 while(left > 0) { 641 len = left; 642 /* IF: it doesn't fit, use 'mtu' - the data space left */ 643 if (len > mtu) 644 len = mtu; 645 /* IF: we are not sending upto and including the packet end 646 then align the next start on an eight byte boundary */ 647 if (len < left) { 648 len &= ~7; 649 } 650 /* 651 * Allocate buffer. 652 */ 653 654 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { 655 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); 656 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 657 err = -ENOMEM; 658 goto fail; 659 } 660 661 /* 662 * Set up data on packet 663 */ 664 665 ip6_copy_metadata(frag, skb); 666 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev)); 667 skb_put(frag, len + hlen + sizeof(struct frag_hdr)); 668 frag->nh.raw = frag->data; 669 fh = (struct frag_hdr*)(frag->data + hlen); 670 frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr); 671 672 /* 673 * Charge the memory for the fragment to any owner 674 * it might possess 675 */ 676 if (skb->sk) 677 skb_set_owner_w(frag, skb->sk); 678 679 /* 680 * Copy the packet header into the new buffer. 681 */ 682 memcpy(frag->nh.raw, skb->data, hlen); 683 684 /* 685 * Build fragment header. 686 */ 687 fh->nexthdr = nexthdr; 688 fh->reserved = 0; 689 if (!frag_id) { 690 ipv6_select_ident(skb, fh); 691 frag_id = fh->identification; 692 } else 693 fh->identification = frag_id; 694 695 /* 696 * Copy a block of the IP datagram. 697 */ 698 if (skb_copy_bits(skb, ptr, frag->h.raw, len)) 699 BUG(); 700 left -= len; 701 702 fh->frag_off = htons(offset); 703 if (left > 0) 704 fh->frag_off |= htons(IP6_MF); 705 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); 706 707 ptr += len; 708 offset += len; 709 710 /* 711 * Put this fragment into the sending queue. 712 */ 713 err = output(frag); 714 if (err) 715 goto fail; 716 717 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES); 718 } 719 kfree_skb(skb); 720 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS); 721 return err; 722 723 fail: 724 kfree_skb(skb); 725 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS); 726 return err; 727 } 728 729 static struct dst_entry *ip6_sk_dst_check(struct sock *sk, 730 struct dst_entry *dst, 731 struct flowi *fl) 732 { 733 struct ipv6_pinfo *np = inet6_sk(sk); 734 struct rt6_info *rt = (struct rt6_info *)dst; 735 736 if (!dst) 737 goto out; 738 739 /* Yes, checking route validity in not connected 740 * case is not very simple. Take into account, 741 * that we do not support routing by source, TOS, 742 * and MSG_DONTROUTE --ANK (980726) 743 * 744 * 1. If route was host route, check that 745 * cached destination is current. 746 * If it is network route, we still may 747 * check its validity using saved pointer 748 * to the last used address: daddr_cache. 749 * We do not want to save whole address now, 750 * (because main consumer of this service 751 * is tcp, which has not this problem), 752 * so that the last trick works only on connected 753 * sockets. 754 * 2. oif also should be the same. 755 */ 756 if (((rt->rt6i_dst.plen != 128 || 757 !ipv6_addr_equal(&fl->fl6_dst, &rt->rt6i_dst.addr)) 758 && (np->daddr_cache == NULL || 759 !ipv6_addr_equal(&fl->fl6_dst, np->daddr_cache))) 760 || (fl->oif && fl->oif != dst->dev->ifindex)) { 761 dst_release(dst); 762 dst = NULL; 763 } 764 765 out: 766 return dst; 767 } 768 769 static int ip6_dst_lookup_tail(struct sock *sk, 770 struct dst_entry **dst, struct flowi *fl) 771 { 772 int err; 773 774 if (*dst == NULL) 775 *dst = ip6_route_output(sk, fl); 776 777 if ((err = (*dst)->error)) 778 goto out_err_release; 779 780 if (ipv6_addr_any(&fl->fl6_src)) { 781 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src); 782 if (err) 783 goto out_err_release; 784 } 785 786 return 0; 787 788 out_err_release: 789 dst_release(*dst); 790 *dst = NULL; 791 return err; 792 } 793 794 /** 795 * ip6_dst_lookup - perform route lookup on flow 796 * @sk: socket which provides route info 797 * @dst: pointer to dst_entry * for result 798 * @fl: flow to lookup 799 * 800 * This function performs a route lookup on the given flow. 801 * 802 * It returns zero on success, or a standard errno code on error. 803 */ 804 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) 805 { 806 *dst = NULL; 807 return ip6_dst_lookup_tail(sk, dst, fl); 808 } 809 EXPORT_SYMBOL_GPL(ip6_dst_lookup); 810 811 /** 812 * ip6_sk_dst_lookup - perform socket cached route lookup on flow 813 * @sk: socket which provides the dst cache and route info 814 * @dst: pointer to dst_entry * for result 815 * @fl: flow to lookup 816 * 817 * This function performs a route lookup on the given flow with the 818 * possibility of using the cached route in the socket if it is valid. 819 * It will take the socket dst lock when operating on the dst cache. 820 * As a result, this function can only be used in process context. 821 * 822 * It returns zero on success, or a standard errno code on error. 823 */ 824 int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) 825 { 826 *dst = NULL; 827 if (sk) { 828 *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); 829 *dst = ip6_sk_dst_check(sk, *dst, fl); 830 } 831 832 return ip6_dst_lookup_tail(sk, dst, fl); 833 } 834 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup); 835 836 static inline int ip6_ufo_append_data(struct sock *sk, 837 int getfrag(void *from, char *to, int offset, int len, 838 int odd, struct sk_buff *skb), 839 void *from, int length, int hh_len, int fragheaderlen, 840 int transhdrlen, int mtu,unsigned int flags) 841 842 { 843 struct sk_buff *skb; 844 int err; 845 846 /* There is support for UDP large send offload by network 847 * device, so create one single skb packet containing complete 848 * udp datagram 849 */ 850 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 851 skb = sock_alloc_send_skb(sk, 852 hh_len + fragheaderlen + transhdrlen + 20, 853 (flags & MSG_DONTWAIT), &err); 854 if (skb == NULL) 855 return -ENOMEM; 856 857 /* reserve space for Hardware header */ 858 skb_reserve(skb, hh_len); 859 860 /* create space for UDP/IP header */ 861 skb_put(skb,fragheaderlen + transhdrlen); 862 863 /* initialize network header pointer */ 864 skb->nh.raw = skb->data; 865 866 /* initialize protocol header pointer */ 867 skb->h.raw = skb->data + fragheaderlen; 868 869 skb->ip_summed = CHECKSUM_HW; 870 skb->csum = 0; 871 sk->sk_sndmsg_off = 0; 872 } 873 874 err = skb_append_datato_frags(sk,skb, getfrag, from, 875 (length - transhdrlen)); 876 if (!err) { 877 struct frag_hdr fhdr; 878 879 /* specify the length of each IP datagram fragment*/ 880 skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 881 sizeof(struct frag_hdr); 882 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 883 ipv6_select_ident(skb, &fhdr); 884 skb_shinfo(skb)->ip6_frag_id = fhdr.identification; 885 __skb_queue_tail(&sk->sk_write_queue, skb); 886 887 return 0; 888 } 889 /* There is not enough support do UPD LSO, 890 * so follow normal path 891 */ 892 kfree_skb(skb); 893 894 return err; 895 } 896 897 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 898 int offset, int len, int odd, struct sk_buff *skb), 899 void *from, int length, int transhdrlen, 900 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl, 901 struct rt6_info *rt, unsigned int flags) 902 { 903 struct inet_sock *inet = inet_sk(sk); 904 struct ipv6_pinfo *np = inet6_sk(sk); 905 struct sk_buff *skb; 906 unsigned int maxfraglen, fragheaderlen; 907 int exthdrlen; 908 int hh_len; 909 int mtu; 910 int copy; 911 int err; 912 int offset = 0; 913 int csummode = CHECKSUM_NONE; 914 915 if (flags&MSG_PROBE) 916 return 0; 917 if (skb_queue_empty(&sk->sk_write_queue)) { 918 /* 919 * setup for corking 920 */ 921 if (opt) { 922 if (np->cork.opt == NULL) { 923 np->cork.opt = kmalloc(opt->tot_len, 924 sk->sk_allocation); 925 if (unlikely(np->cork.opt == NULL)) 926 return -ENOBUFS; 927 } else if (np->cork.opt->tot_len < opt->tot_len) { 928 printk(KERN_DEBUG "ip6_append_data: invalid option length\n"); 929 return -EINVAL; 930 } 931 memcpy(np->cork.opt, opt, opt->tot_len); 932 inet->cork.flags |= IPCORK_OPT; 933 /* need source address above miyazawa*/ 934 } 935 dst_hold(&rt->u.dst); 936 np->cork.rt = rt; 937 inet->cork.fl = *fl; 938 np->cork.hop_limit = hlimit; 939 np->cork.tclass = tclass; 940 mtu = dst_mtu(rt->u.dst.path); 941 if (np->frag_size < mtu) { 942 if (np->frag_size) 943 mtu = np->frag_size; 944 } 945 inet->cork.fragsize = mtu; 946 if (dst_allfrag(rt->u.dst.path)) 947 inet->cork.flags |= IPCORK_ALLFRAG; 948 inet->cork.length = 0; 949 sk->sk_sndmsg_page = NULL; 950 sk->sk_sndmsg_off = 0; 951 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0); 952 length += exthdrlen; 953 transhdrlen += exthdrlen; 954 } else { 955 rt = np->cork.rt; 956 fl = &inet->cork.fl; 957 if (inet->cork.flags & IPCORK_OPT) 958 opt = np->cork.opt; 959 transhdrlen = 0; 960 exthdrlen = 0; 961 mtu = inet->cork.fragsize; 962 } 963 964 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 965 966 fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0); 967 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); 968 969 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { 970 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { 971 ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen); 972 return -EMSGSIZE; 973 } 974 } 975 976 /* 977 * Let's try using as much space as possible. 978 * Use MTU if total length of the message fits into the MTU. 979 * Otherwise, we need to reserve fragment header and 980 * fragment alignment (= 8-15 octects, in total). 981 * 982 * Note that we may need to "move" the data from the tail of 983 * of the buffer to the new fragment when we split 984 * the message. 985 * 986 * FIXME: It may be fragmented into multiple chunks 987 * at once if non-fragmentable extension headers 988 * are too large. 989 * --yoshfuji 990 */ 991 992 inet->cork.length += length; 993 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 994 (rt->u.dst.dev->features & NETIF_F_UFO)) { 995 996 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, 997 fragheaderlen, transhdrlen, mtu, 998 flags); 999 if (err) 1000 goto error; 1001 return 0; 1002 } 1003 1004 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1005 goto alloc_new_skb; 1006 1007 while (length > 0) { 1008 /* Check if the remaining data fits into current packet. */ 1009 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; 1010 if (copy < length) 1011 copy = maxfraglen - skb->len; 1012 1013 if (copy <= 0) { 1014 char *data; 1015 unsigned int datalen; 1016 unsigned int fraglen; 1017 unsigned int fraggap; 1018 unsigned int alloclen; 1019 struct sk_buff *skb_prev; 1020 alloc_new_skb: 1021 skb_prev = skb; 1022 1023 /* There's no room in the current skb */ 1024 if (skb_prev) 1025 fraggap = skb_prev->len - maxfraglen; 1026 else 1027 fraggap = 0; 1028 1029 /* 1030 * If remaining data exceeds the mtu, 1031 * we know we need more fragment(s). 1032 */ 1033 datalen = length + fraggap; 1034 if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) 1035 datalen = maxfraglen - fragheaderlen; 1036 1037 fraglen = datalen + fragheaderlen; 1038 if ((flags & MSG_MORE) && 1039 !(rt->u.dst.dev->features&NETIF_F_SG)) 1040 alloclen = mtu; 1041 else 1042 alloclen = datalen + fragheaderlen; 1043 1044 /* 1045 * The last fragment gets additional space at tail. 1046 * Note: we overallocate on fragments with MSG_MODE 1047 * because we have no idea if we're the last one. 1048 */ 1049 if (datalen == length + fraggap) 1050 alloclen += rt->u.dst.trailer_len; 1051 1052 /* 1053 * We just reserve space for fragment header. 1054 * Note: this may be overallocation if the message 1055 * (without MSG_MORE) fits into the MTU. 1056 */ 1057 alloclen += sizeof(struct frag_hdr); 1058 1059 if (transhdrlen) { 1060 skb = sock_alloc_send_skb(sk, 1061 alloclen + hh_len, 1062 (flags & MSG_DONTWAIT), &err); 1063 } else { 1064 skb = NULL; 1065 if (atomic_read(&sk->sk_wmem_alloc) <= 1066 2 * sk->sk_sndbuf) 1067 skb = sock_wmalloc(sk, 1068 alloclen + hh_len, 1, 1069 sk->sk_allocation); 1070 if (unlikely(skb == NULL)) 1071 err = -ENOBUFS; 1072 } 1073 if (skb == NULL) 1074 goto error; 1075 /* 1076 * Fill in the control structures 1077 */ 1078 skb->ip_summed = csummode; 1079 skb->csum = 0; 1080 /* reserve for fragmentation */ 1081 skb_reserve(skb, hh_len+sizeof(struct frag_hdr)); 1082 1083 /* 1084 * Find where to start putting bytes 1085 */ 1086 data = skb_put(skb, fraglen); 1087 skb->nh.raw = data + exthdrlen; 1088 data += fragheaderlen; 1089 skb->h.raw = data + exthdrlen; 1090 1091 if (fraggap) { 1092 skb->csum = skb_copy_and_csum_bits( 1093 skb_prev, maxfraglen, 1094 data + transhdrlen, fraggap, 0); 1095 skb_prev->csum = csum_sub(skb_prev->csum, 1096 skb->csum); 1097 data += fraggap; 1098 skb_trim(skb_prev, maxfraglen); 1099 } 1100 copy = datalen - transhdrlen - fraggap; 1101 if (copy < 0) { 1102 err = -EINVAL; 1103 kfree_skb(skb); 1104 goto error; 1105 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 1106 err = -EFAULT; 1107 kfree_skb(skb); 1108 goto error; 1109 } 1110 1111 offset += copy; 1112 length -= datalen - fraggap; 1113 transhdrlen = 0; 1114 exthdrlen = 0; 1115 csummode = CHECKSUM_NONE; 1116 1117 /* 1118 * Put the packet on the pending queue 1119 */ 1120 __skb_queue_tail(&sk->sk_write_queue, skb); 1121 continue; 1122 } 1123 1124 if (copy > length) 1125 copy = length; 1126 1127 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 1128 unsigned int off; 1129 1130 off = skb->len; 1131 if (getfrag(from, skb_put(skb, copy), 1132 offset, copy, off, skb) < 0) { 1133 __skb_trim(skb, off); 1134 err = -EFAULT; 1135 goto error; 1136 } 1137 } else { 1138 int i = skb_shinfo(skb)->nr_frags; 1139 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1140 struct page *page = sk->sk_sndmsg_page; 1141 int off = sk->sk_sndmsg_off; 1142 unsigned int left; 1143 1144 if (page && (left = PAGE_SIZE - off) > 0) { 1145 if (copy >= left) 1146 copy = left; 1147 if (page != frag->page) { 1148 if (i == MAX_SKB_FRAGS) { 1149 err = -EMSGSIZE; 1150 goto error; 1151 } 1152 get_page(page); 1153 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1154 frag = &skb_shinfo(skb)->frags[i]; 1155 } 1156 } else if(i < MAX_SKB_FRAGS) { 1157 if (copy > PAGE_SIZE) 1158 copy = PAGE_SIZE; 1159 page = alloc_pages(sk->sk_allocation, 0); 1160 if (page == NULL) { 1161 err = -ENOMEM; 1162 goto error; 1163 } 1164 sk->sk_sndmsg_page = page; 1165 sk->sk_sndmsg_off = 0; 1166 1167 skb_fill_page_desc(skb, i, page, 0, 0); 1168 frag = &skb_shinfo(skb)->frags[i]; 1169 skb->truesize += PAGE_SIZE; 1170 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1171 } else { 1172 err = -EMSGSIZE; 1173 goto error; 1174 } 1175 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1176 err = -EFAULT; 1177 goto error; 1178 } 1179 sk->sk_sndmsg_off += copy; 1180 frag->size += copy; 1181 skb->len += copy; 1182 skb->data_len += copy; 1183 } 1184 offset += copy; 1185 length -= copy; 1186 } 1187 return 0; 1188 error: 1189 inet->cork.length -= length; 1190 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1191 return err; 1192 } 1193 1194 int ip6_push_pending_frames(struct sock *sk) 1195 { 1196 struct sk_buff *skb, *tmp_skb; 1197 struct sk_buff **tail_skb; 1198 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; 1199 struct inet_sock *inet = inet_sk(sk); 1200 struct ipv6_pinfo *np = inet6_sk(sk); 1201 struct ipv6hdr *hdr; 1202 struct ipv6_txoptions *opt = np->cork.opt; 1203 struct rt6_info *rt = np->cork.rt; 1204 struct flowi *fl = &inet->cork.fl; 1205 unsigned char proto = fl->proto; 1206 int err = 0; 1207 1208 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1209 goto out; 1210 tail_skb = &(skb_shinfo(skb)->frag_list); 1211 1212 /* move skb->data to ip header from ext header */ 1213 if (skb->data < skb->nh.raw) 1214 __skb_pull(skb, skb->nh.raw - skb->data); 1215 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1216 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1217 *tail_skb = tmp_skb; 1218 tail_skb = &(tmp_skb->next); 1219 skb->len += tmp_skb->len; 1220 skb->data_len += tmp_skb->len; 1221 skb->truesize += tmp_skb->truesize; 1222 __sock_put(tmp_skb->sk); 1223 tmp_skb->destructor = NULL; 1224 tmp_skb->sk = NULL; 1225 } 1226 1227 ipv6_addr_copy(final_dst, &fl->fl6_dst); 1228 __skb_pull(skb, skb->h.raw - skb->nh.raw); 1229 if (opt && opt->opt_flen) 1230 ipv6_push_frag_opts(skb, opt, &proto); 1231 if (opt && opt->opt_nflen) 1232 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); 1233 1234 skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr)); 1235 1236 *(u32*)hdr = fl->fl6_flowlabel | 1237 htonl(0x60000000 | ((int)np->cork.tclass << 20)); 1238 1239 if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) 1240 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 1241 else 1242 hdr->payload_len = 0; 1243 hdr->hop_limit = np->cork.hop_limit; 1244 hdr->nexthdr = proto; 1245 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); 1246 ipv6_addr_copy(&hdr->daddr, final_dst); 1247 1248 skb->priority = sk->sk_priority; 1249 1250 skb->dst = dst_clone(&rt->u.dst); 1251 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 1252 err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output); 1253 if (err) { 1254 if (err > 0) 1255 err = np->recverr ? net_xmit_errno(err) : 0; 1256 if (err) 1257 goto error; 1258 } 1259 1260 out: 1261 inet->cork.flags &= ~IPCORK_OPT; 1262 kfree(np->cork.opt); 1263 np->cork.opt = NULL; 1264 if (np->cork.rt) { 1265 dst_release(&np->cork.rt->u.dst); 1266 np->cork.rt = NULL; 1267 inet->cork.flags &= ~IPCORK_ALLFRAG; 1268 } 1269 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1270 return err; 1271 error: 1272 goto out; 1273 } 1274 1275 void ip6_flush_pending_frames(struct sock *sk) 1276 { 1277 struct inet_sock *inet = inet_sk(sk); 1278 struct ipv6_pinfo *np = inet6_sk(sk); 1279 struct sk_buff *skb; 1280 1281 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { 1282 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1283 kfree_skb(skb); 1284 } 1285 1286 inet->cork.flags &= ~IPCORK_OPT; 1287 1288 kfree(np->cork.opt); 1289 np->cork.opt = NULL; 1290 if (np->cork.rt) { 1291 dst_release(&np->cork.rt->u.dst); 1292 np->cork.rt = NULL; 1293 inet->cork.flags &= ~IPCORK_ALLFRAG; 1294 } 1295 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); 1296 } 1297