ip_output.c revision 3644f0cee77494190452de132e82245107939284
1/* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * The Internet Protocol (IP) output module. 7 * 8 * Version: $Id: ip_output.c,v 1.100 2002/02/01 22:01:03 davem Exp $ 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Donald Becker, <becker@super.org> 13 * Alan Cox, <Alan.Cox@linux.org> 14 * Richard Underwood 15 * Stefan Becker, <stefanb@yello.ping.de> 16 * Jorge Cwik, <jorge@laser.satlink.net> 17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 18 * Hirokazu Takahashi, <taka@valinux.co.jp> 19 * 20 * See ip_input.c for original log 21 * 22 * Fixes: 23 * Alan Cox : Missing nonblock feature in ip_build_xmit. 24 * Mike Kilburn : htons() missing in ip_build_xmit. 25 * Bradford Johnson: Fix faulty handling of some frames when 26 * no route is found. 27 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit 28 * (in case if packet not accepted by 29 * output firewall rules) 30 * Mike McLagan : Routing by source 31 * Alexey Kuznetsov: use new route cache 32 * Andi Kleen: Fix broken PMTU recovery and remove 33 * some redundant tests. 34 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 35 * Andi Kleen : Replace ip_reply with ip_send_reply. 36 * Andi Kleen : Split fast and slow ip_build_xmit path 37 * for decreased register pressure on x86 38 * and more readibility. 39 * Marc Boucher : When call_out_firewall returns FW_QUEUE, 40 * silently drop skb instead of failing with -EPERM. 41 * Detlev Wengorz : Copy protocol for fragments. 42 * Hirokazu Takahashi: HW checksumming for outgoing UDP 43 * datagrams. 44 * Hirokazu Takahashi: sendfile() on UDP works now. 45 */ 46 47#include <asm/uaccess.h> 48#include <asm/system.h> 49#include <linux/module.h> 50#include <linux/types.h> 51#include <linux/kernel.h> 52#include <linux/sched.h> 53#include <linux/mm.h> 54#include <linux/string.h> 55#include <linux/errno.h> 56#include <linux/highmem.h> 57 58#include <linux/socket.h> 59#include <linux/sockios.h> 60#include <linux/in.h> 61#include <linux/inet.h> 62#include <linux/netdevice.h> 63#include <linux/etherdevice.h> 64#include <linux/proc_fs.h> 65#include <linux/stat.h> 66#include <linux/init.h> 67 68#include <net/snmp.h> 69#include <net/ip.h> 70#include <net/protocol.h> 71#include <net/route.h> 72#include <net/xfrm.h> 73#include <linux/skbuff.h> 74#include <net/sock.h> 75#include <net/arp.h> 76#include <net/icmp.h> 77#include <net/checksum.h> 78#include <net/inetpeer.h> 79#include <net/checksum.h> 80#include <linux/igmp.h> 81#include <linux/netfilter_ipv4.h> 82#include <linux/netfilter_bridge.h> 83#include <linux/mroute.h> 84#include <linux/netlink.h> 85#include <linux/tcp.h> 86 87int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; 88 89/* Generate a checksum for an outgoing IP datagram. */ 90__inline__ void ip_send_check(struct iphdr *iph) 91{ 92 iph->check = 0; 93 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 94} 95 96/* dev_loopback_xmit for use with netfilter. */ 97static int ip_dev_loopback_xmit(struct sk_buff *newskb) 98{ 99 newskb->mac.raw = newskb->data; 100 __skb_pull(newskb, newskb->nh.raw - newskb->data); 101 newskb->pkt_type = PACKET_LOOPBACK; 102 newskb->ip_summed = CHECKSUM_UNNECESSARY; 103 BUG_TRAP(newskb->dst); 104 netif_rx(newskb); 105 return 0; 106} 107 108static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) 109{ 110 int ttl = inet->uc_ttl; 111 112 if (ttl < 0) 113 ttl = dst_metric(dst, RTAX_HOPLIMIT); 114 return ttl; 115} 116 117/* 118 * Add an ip header to a skbuff and send it out. 119 * 120 */ 121int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 122 __be32 saddr, __be32 daddr, struct ip_options *opt) 123{ 124 struct inet_sock *inet = inet_sk(sk); 125 struct rtable *rt = (struct rtable *)skb->dst; 126 struct iphdr *iph; 127 128 /* Build the IP header. */ 129 if (opt) 130 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); 131 else 132 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); 133 134 iph->version = 4; 135 iph->ihl = 5; 136 iph->tos = inet->tos; 137 if (ip_dont_fragment(sk, &rt->u.dst)) 138 iph->frag_off = htons(IP_DF); 139 else 140 iph->frag_off = 0; 141 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 142 iph->daddr = rt->rt_dst; 143 iph->saddr = rt->rt_src; 144 iph->protocol = sk->sk_protocol; 145 iph->tot_len = htons(skb->len); 146 ip_select_ident(iph, &rt->u.dst, sk); 147 skb->nh.iph = iph; 148 149 if (opt && opt->optlen) { 150 iph->ihl += opt->optlen>>2; 151 ip_options_build(skb, opt, daddr, rt, 0); 152 } 153 ip_send_check(iph); 154 155 skb->priority = sk->sk_priority; 156 157 /* Send it out. */ 158 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 159 dst_output); 160} 161 162EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); 163 164static inline int ip_finish_output2(struct sk_buff *skb) 165{ 166 struct dst_entry *dst = skb->dst; 167 struct net_device *dev = dst->dev; 168 int hh_len = LL_RESERVED_SPACE(dev); 169 170 /* Be paranoid, rather than too clever. */ 171 if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) { 172 struct sk_buff *skb2; 173 174 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); 175 if (skb2 == NULL) { 176 kfree_skb(skb); 177 return -ENOMEM; 178 } 179 if (skb->sk) 180 skb_set_owner_w(skb2, skb->sk); 181 kfree_skb(skb); 182 skb = skb2; 183 } 184 185 if (dst->hh) 186 return neigh_hh_output(dst->hh, skb); 187 else if (dst->neighbour) 188 return dst->neighbour->output(skb); 189 190 if (net_ratelimit()) 191 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); 192 kfree_skb(skb); 193 return -EINVAL; 194} 195 196static inline int ip_finish_output(struct sk_buff *skb) 197{ 198#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 199 /* Policy lookup after SNAT yielded a new policy */ 200 if (skb->dst->xfrm != NULL) { 201 IPCB(skb)->flags |= IPSKB_REROUTED; 202 return dst_output(skb); 203 } 204#endif 205 if (skb->len > dst_mtu(skb->dst) && !skb_is_gso(skb)) 206 return ip_fragment(skb, ip_finish_output2); 207 else 208 return ip_finish_output2(skb); 209} 210 211int ip_mc_output(struct sk_buff *skb) 212{ 213 struct sock *sk = skb->sk; 214 struct rtable *rt = (struct rtable*)skb->dst; 215 struct net_device *dev = rt->u.dst.dev; 216 217 /* 218 * If the indicated interface is up and running, send the packet. 219 */ 220 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 221 222 skb->dev = dev; 223 skb->protocol = htons(ETH_P_IP); 224 225 /* 226 * Multicasts are looped back for other local users 227 */ 228 229 if (rt->rt_flags&RTCF_MULTICAST) { 230 if ((!sk || inet_sk(sk)->mc_loop) 231#ifdef CONFIG_IP_MROUTE 232 /* Small optimization: do not loopback not local frames, 233 which returned after forwarding; they will be dropped 234 by ip_mr_input in any case. 235 Note, that local frames are looped back to be delivered 236 to local recipients. 237 238 This check is duplicated in ip_mr_input at the moment. 239 */ 240 && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) 241#endif 242 ) { 243 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 244 if (newskb) 245 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 246 newskb->dev, 247 ip_dev_loopback_xmit); 248 } 249 250 /* Multicasts with ttl 0 must not go beyond the host */ 251 252 if (skb->nh.iph->ttl == 0) { 253 kfree_skb(skb); 254 return 0; 255 } 256 } 257 258 if (rt->rt_flags&RTCF_BROADCAST) { 259 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 260 if (newskb) 261 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 262 newskb->dev, ip_dev_loopback_xmit); 263 } 264 265 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev, 266 ip_finish_output, 267 !(IPCB(skb)->flags & IPSKB_REROUTED)); 268} 269 270int ip_output(struct sk_buff *skb) 271{ 272 struct net_device *dev = skb->dst->dev; 273 274 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 275 276 skb->dev = dev; 277 skb->protocol = htons(ETH_P_IP); 278 279 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, 280 ip_finish_output, 281 !(IPCB(skb)->flags & IPSKB_REROUTED)); 282} 283 284int ip_queue_xmit(struct sk_buff *skb, struct sock *sk, int ipfragok) 285{ 286 struct inet_sock *inet = inet_sk(sk); 287 struct ip_options *opt = inet->opt; 288 struct rtable *rt; 289 struct iphdr *iph; 290 291 /* Skip all of this if the packet is already routed, 292 * f.e. by something like SCTP. 293 */ 294 rt = (struct rtable *) skb->dst; 295 if (rt != NULL) 296 goto packet_routed; 297 298 /* Make sure we can route this packet. */ 299 rt = (struct rtable *)__sk_dst_check(sk, 0); 300 if (rt == NULL) { 301 __be32 daddr; 302 303 /* Use correct destination address if we have options. */ 304 daddr = inet->daddr; 305 if(opt && opt->srr) 306 daddr = opt->faddr; 307 308 { 309 struct flowi fl = { .oif = sk->sk_bound_dev_if, 310 .nl_u = { .ip4_u = 311 { .daddr = daddr, 312 .saddr = inet->saddr, 313 .tos = RT_CONN_FLAGS(sk) } }, 314 .proto = sk->sk_protocol, 315 .uli_u = { .ports = 316 { .sport = inet->sport, 317 .dport = inet->dport } } }; 318 319 /* If this fails, retransmit mechanism of transport layer will 320 * keep trying until route appears or the connection times 321 * itself out. 322 */ 323 security_sk_classify_flow(sk, &fl); 324 if (ip_route_output_flow(&rt, &fl, sk, 0)) 325 goto no_route; 326 } 327 sk_setup_caps(sk, &rt->u.dst); 328 } 329 skb->dst = dst_clone(&rt->u.dst); 330 331packet_routed: 332 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) 333 goto no_route; 334 335 /* OK, we know where to send it, allocate and build IP header. */ 336 iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 337 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); 338 iph->tot_len = htons(skb->len); 339 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) 340 iph->frag_off = htons(IP_DF); 341 else 342 iph->frag_off = 0; 343 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 344 iph->protocol = sk->sk_protocol; 345 iph->saddr = rt->rt_src; 346 iph->daddr = rt->rt_dst; 347 skb->nh.iph = iph; 348 /* Transport layer set skb->h.foo itself. */ 349 350 if (opt && opt->optlen) { 351 iph->ihl += opt->optlen >> 2; 352 ip_options_build(skb, opt, inet->daddr, rt, 0); 353 } 354 355 ip_select_ident_more(iph, &rt->u.dst, sk, 356 (skb_shinfo(skb)->gso_segs ?: 1) - 1); 357 358 /* Add an IP checksum. */ 359 ip_send_check(iph); 360 361 skb->priority = sk->sk_priority; 362 363 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 364 dst_output); 365 366no_route: 367 IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); 368 kfree_skb(skb); 369 return -EHOSTUNREACH; 370} 371 372 373static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) 374{ 375 to->pkt_type = from->pkt_type; 376 to->priority = from->priority; 377 to->protocol = from->protocol; 378 dst_release(to->dst); 379 to->dst = dst_clone(from->dst); 380 to->dev = from->dev; 381 to->mark = from->mark; 382 383 /* Copy the flags to each fragment. */ 384 IPCB(to)->flags = IPCB(from)->flags; 385 386#ifdef CONFIG_NET_SCHED 387 to->tc_index = from->tc_index; 388#endif 389#ifdef CONFIG_NETFILTER 390 /* Connection association is same as pre-frag packet */ 391 nf_conntrack_put(to->nfct); 392 to->nfct = from->nfct; 393 nf_conntrack_get(to->nfct); 394 to->nfctinfo = from->nfctinfo; 395#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 396 to->ipvs_property = from->ipvs_property; 397#endif 398#ifdef CONFIG_BRIDGE_NETFILTER 399 nf_bridge_put(to->nf_bridge); 400 to->nf_bridge = from->nf_bridge; 401 nf_bridge_get(to->nf_bridge); 402#endif 403#endif 404 skb_copy_secmark(to, from); 405} 406 407/* 408 * This IP datagram is too large to be sent in one piece. Break it up into 409 * smaller pieces (each of size equal to IP header plus 410 * a block of the data of the original IP data part) that will yet fit in a 411 * single device frame, and queue such a frame for sending. 412 */ 413 414int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) 415{ 416 struct iphdr *iph; 417 int raw = 0; 418 int ptr; 419 struct net_device *dev; 420 struct sk_buff *skb2; 421 unsigned int mtu, hlen, left, len, ll_rs, pad; 422 int offset; 423 __be16 not_last_frag; 424 struct rtable *rt = (struct rtable*)skb->dst; 425 int err = 0; 426 427 dev = rt->u.dst.dev; 428 429 /* 430 * Point into the IP datagram header. 431 */ 432 433 iph = skb->nh.iph; 434 435 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { 436 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 437 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 438 htonl(dst_mtu(&rt->u.dst))); 439 kfree_skb(skb); 440 return -EMSGSIZE; 441 } 442 443 /* 444 * Setup starting values. 445 */ 446 447 hlen = iph->ihl * 4; 448 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 449 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 450 451 /* When frag_list is given, use it. First, check its validity: 452 * some transformers could create wrong frag_list or break existing 453 * one, it is not prohibited. In this case fall back to copying. 454 * 455 * LATER: this step can be merged to real generation of fragments, 456 * we can switch to copy when see the first bad fragment. 457 */ 458 if (skb_shinfo(skb)->frag_list) { 459 struct sk_buff *frag; 460 int first_len = skb_pagelen(skb); 461 462 if (first_len - hlen > mtu || 463 ((first_len - hlen) & 7) || 464 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 465 skb_cloned(skb)) 466 goto slow_path; 467 468 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 469 /* Correct geometry. */ 470 if (frag->len > mtu || 471 ((frag->len & 7) && frag->next) || 472 skb_headroom(frag) < hlen) 473 goto slow_path; 474 475 /* Partially cloned skb? */ 476 if (skb_shared(frag)) 477 goto slow_path; 478 479 BUG_ON(frag->sk); 480 if (skb->sk) { 481 sock_hold(skb->sk); 482 frag->sk = skb->sk; 483 frag->destructor = sock_wfree; 484 skb->truesize -= frag->truesize; 485 } 486 } 487 488 /* Everything is OK. Generate! */ 489 490 err = 0; 491 offset = 0; 492 frag = skb_shinfo(skb)->frag_list; 493 skb_shinfo(skb)->frag_list = NULL; 494 skb->data_len = first_len - skb_headlen(skb); 495 skb->len = first_len; 496 iph->tot_len = htons(first_len); 497 iph->frag_off = htons(IP_MF); 498 ip_send_check(iph); 499 500 for (;;) { 501 /* Prepare header of the next frame, 502 * before previous one went down. */ 503 if (frag) { 504 frag->ip_summed = CHECKSUM_NONE; 505 frag->h.raw = frag->data; 506 frag->nh.raw = __skb_push(frag, hlen); 507 memcpy(frag->nh.raw, iph, hlen); 508 iph = frag->nh.iph; 509 iph->tot_len = htons(frag->len); 510 ip_copy_metadata(frag, skb); 511 if (offset == 0) 512 ip_options_fragment(frag); 513 offset += skb->len - hlen; 514 iph->frag_off = htons(offset>>3); 515 if (frag->next != NULL) 516 iph->frag_off |= htons(IP_MF); 517 /* Ready, complete checksum */ 518 ip_send_check(iph); 519 } 520 521 err = output(skb); 522 523 if (!err) 524 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 525 if (err || !frag) 526 break; 527 528 skb = frag; 529 frag = skb->next; 530 skb->next = NULL; 531 } 532 533 if (err == 0) { 534 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 535 return 0; 536 } 537 538 while (frag) { 539 skb = frag->next; 540 kfree_skb(frag); 541 frag = skb; 542 } 543 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 544 return err; 545 } 546 547slow_path: 548 left = skb->len - hlen; /* Space per frame */ 549 ptr = raw + hlen; /* Where to start from */ 550 551 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 552 * we need to make room for the encapsulating header 553 */ 554 pad = nf_bridge_pad(skb); 555 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad); 556 mtu -= pad; 557 558 /* 559 * Fragment the datagram. 560 */ 561 562 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 563 not_last_frag = iph->frag_off & htons(IP_MF); 564 565 /* 566 * Keep copying data until we run out. 567 */ 568 569 while(left > 0) { 570 len = left; 571 /* IF: it doesn't fit, use 'mtu' - the data space left */ 572 if (len > mtu) 573 len = mtu; 574 /* IF: we are not sending upto and including the packet end 575 then align the next start on an eight byte boundary */ 576 if (len < left) { 577 len &= ~7; 578 } 579 /* 580 * Allocate buffer. 581 */ 582 583 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 584 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 585 err = -ENOMEM; 586 goto fail; 587 } 588 589 /* 590 * Set up data on packet 591 */ 592 593 ip_copy_metadata(skb2, skb); 594 skb_reserve(skb2, ll_rs); 595 skb_put(skb2, len + hlen); 596 skb2->nh.raw = skb2->data; 597 skb2->h.raw = skb2->data + hlen; 598 599 /* 600 * Charge the memory for the fragment to any owner 601 * it might possess 602 */ 603 604 if (skb->sk) 605 skb_set_owner_w(skb2, skb->sk); 606 607 /* 608 * Copy the packet header into the new buffer. 609 */ 610 611 memcpy(skb2->nh.raw, skb->data, hlen); 612 613 /* 614 * Copy a block of the IP datagram. 615 */ 616 if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) 617 BUG(); 618 left -= len; 619 620 /* 621 * Fill in the new header fields. 622 */ 623 iph = skb2->nh.iph; 624 iph->frag_off = htons((offset >> 3)); 625 626 /* ANK: dirty, but effective trick. Upgrade options only if 627 * the segment to be fragmented was THE FIRST (otherwise, 628 * options are already fixed) and make it ONCE 629 * on the initial skb, so that all the following fragments 630 * will inherit fixed options. 631 */ 632 if (offset == 0) 633 ip_options_fragment(skb); 634 635 /* 636 * Added AC : If we are fragmenting a fragment that's not the 637 * last fragment then keep MF on each bit 638 */ 639 if (left > 0 || not_last_frag) 640 iph->frag_off |= htons(IP_MF); 641 ptr += len; 642 offset += len; 643 644 /* 645 * Put this fragment into the sending queue. 646 */ 647 iph->tot_len = htons(len + hlen); 648 649 ip_send_check(iph); 650 651 err = output(skb2); 652 if (err) 653 goto fail; 654 655 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 656 } 657 kfree_skb(skb); 658 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 659 return err; 660 661fail: 662 kfree_skb(skb); 663 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 664 return err; 665} 666 667EXPORT_SYMBOL(ip_fragment); 668 669int 670ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 671{ 672 struct iovec *iov = from; 673 674 if (skb->ip_summed == CHECKSUM_PARTIAL) { 675 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 676 return -EFAULT; 677 } else { 678 __wsum csum = 0; 679 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 680 return -EFAULT; 681 skb->csum = csum_block_add(skb->csum, csum, odd); 682 } 683 return 0; 684} 685 686static inline __wsum 687csum_page(struct page *page, int offset, int copy) 688{ 689 char *kaddr; 690 __wsum csum; 691 kaddr = kmap(page); 692 csum = csum_partial(kaddr + offset, copy, 0); 693 kunmap(page); 694 return csum; 695} 696 697static inline int ip_ufo_append_data(struct sock *sk, 698 int getfrag(void *from, char *to, int offset, int len, 699 int odd, struct sk_buff *skb), 700 void *from, int length, int hh_len, int fragheaderlen, 701 int transhdrlen, int mtu,unsigned int flags) 702{ 703 struct sk_buff *skb; 704 int err; 705 706 /* There is support for UDP fragmentation offload by network 707 * device, so create one single skb packet containing complete 708 * udp datagram 709 */ 710 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 711 skb = sock_alloc_send_skb(sk, 712 hh_len + fragheaderlen + transhdrlen + 20, 713 (flags & MSG_DONTWAIT), &err); 714 715 if (skb == NULL) 716 return err; 717 718 /* reserve space for Hardware header */ 719 skb_reserve(skb, hh_len); 720 721 /* create space for UDP/IP header */ 722 skb_put(skb,fragheaderlen + transhdrlen); 723 724 /* initialize network header pointer */ 725 skb->nh.raw = skb->data; 726 727 /* initialize protocol header pointer */ 728 skb->h.raw = skb->data + fragheaderlen; 729 730 skb->ip_summed = CHECKSUM_PARTIAL; 731 skb->csum = 0; 732 sk->sk_sndmsg_off = 0; 733 } 734 735 err = skb_append_datato_frags(sk,skb, getfrag, from, 736 (length - transhdrlen)); 737 if (!err) { 738 /* specify the length of each IP datagram fragment*/ 739 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 740 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 741 __skb_queue_tail(&sk->sk_write_queue, skb); 742 743 return 0; 744 } 745 /* There is not enough support do UFO , 746 * so follow normal path 747 */ 748 kfree_skb(skb); 749 return err; 750} 751 752/* 753 * ip_append_data() and ip_append_page() can make one large IP datagram 754 * from many pieces of data. Each pieces will be holded on the socket 755 * until ip_push_pending_frames() is called. Each piece can be a page 756 * or non-page data. 757 * 758 * Not only UDP, other transport protocols - e.g. raw sockets - can use 759 * this interface potentially. 760 * 761 * LATER: length must be adjusted by pad at tail, when it is required. 762 */ 763int ip_append_data(struct sock *sk, 764 int getfrag(void *from, char *to, int offset, int len, 765 int odd, struct sk_buff *skb), 766 void *from, int length, int transhdrlen, 767 struct ipcm_cookie *ipc, struct rtable *rt, 768 unsigned int flags) 769{ 770 struct inet_sock *inet = inet_sk(sk); 771 struct sk_buff *skb; 772 773 struct ip_options *opt = NULL; 774 int hh_len; 775 int exthdrlen; 776 int mtu; 777 int copy; 778 int err; 779 int offset = 0; 780 unsigned int maxfraglen, fragheaderlen; 781 int csummode = CHECKSUM_NONE; 782 783 if (flags&MSG_PROBE) 784 return 0; 785 786 if (skb_queue_empty(&sk->sk_write_queue)) { 787 /* 788 * setup for corking. 789 */ 790 opt = ipc->opt; 791 if (opt) { 792 if (inet->cork.opt == NULL) { 793 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 794 if (unlikely(inet->cork.opt == NULL)) 795 return -ENOBUFS; 796 } 797 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 798 inet->cork.flags |= IPCORK_OPT; 799 inet->cork.addr = ipc->addr; 800 } 801 dst_hold(&rt->u.dst); 802 inet->cork.fragsize = mtu = dst_mtu(rt->u.dst.path); 803 inet->cork.rt = rt; 804 inet->cork.length = 0; 805 sk->sk_sndmsg_page = NULL; 806 sk->sk_sndmsg_off = 0; 807 if ((exthdrlen = rt->u.dst.header_len) != 0) { 808 length += exthdrlen; 809 transhdrlen += exthdrlen; 810 } 811 } else { 812 rt = inet->cork.rt; 813 if (inet->cork.flags & IPCORK_OPT) 814 opt = inet->cork.opt; 815 816 transhdrlen = 0; 817 exthdrlen = 0; 818 mtu = inet->cork.fragsize; 819 } 820 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 821 822 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 823 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 824 825 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 826 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 827 return -EMSGSIZE; 828 } 829 830 /* 831 * transhdrlen > 0 means that this is the first fragment and we wish 832 * it won't be fragmented in the future. 833 */ 834 if (transhdrlen && 835 length + fragheaderlen <= mtu && 836 rt->u.dst.dev->features & NETIF_F_ALL_CSUM && 837 !exthdrlen) 838 csummode = CHECKSUM_PARTIAL; 839 840 inet->cork.length += length; 841 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 842 (rt->u.dst.dev->features & NETIF_F_UFO)) { 843 844 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 845 fragheaderlen, transhdrlen, mtu, 846 flags); 847 if (err) 848 goto error; 849 return 0; 850 } 851 852 /* So, what's going on in the loop below? 853 * 854 * We use calculated fragment length to generate chained skb, 855 * each of segments is IP fragment ready for sending to network after 856 * adding appropriate IP header. 857 */ 858 859 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 860 goto alloc_new_skb; 861 862 while (length > 0) { 863 /* Check if the remaining data fits into current packet. */ 864 copy = mtu - skb->len; 865 if (copy < length) 866 copy = maxfraglen - skb->len; 867 if (copy <= 0) { 868 char *data; 869 unsigned int datalen; 870 unsigned int fraglen; 871 unsigned int fraggap; 872 unsigned int alloclen; 873 struct sk_buff *skb_prev; 874alloc_new_skb: 875 skb_prev = skb; 876 if (skb_prev) 877 fraggap = skb_prev->len - maxfraglen; 878 else 879 fraggap = 0; 880 881 /* 882 * If remaining data exceeds the mtu, 883 * we know we need more fragment(s). 884 */ 885 datalen = length + fraggap; 886 if (datalen > mtu - fragheaderlen) 887 datalen = maxfraglen - fragheaderlen; 888 fraglen = datalen + fragheaderlen; 889 890 if ((flags & MSG_MORE) && 891 !(rt->u.dst.dev->features&NETIF_F_SG)) 892 alloclen = mtu; 893 else 894 alloclen = datalen + fragheaderlen; 895 896 /* The last fragment gets additional space at tail. 897 * Note, with MSG_MORE we overallocate on fragments, 898 * because we have no idea what fragment will be 899 * the last. 900 */ 901 if (datalen == length + fraggap) 902 alloclen += rt->u.dst.trailer_len; 903 904 if (transhdrlen) { 905 skb = sock_alloc_send_skb(sk, 906 alloclen + hh_len + 15, 907 (flags & MSG_DONTWAIT), &err); 908 } else { 909 skb = NULL; 910 if (atomic_read(&sk->sk_wmem_alloc) <= 911 2 * sk->sk_sndbuf) 912 skb = sock_wmalloc(sk, 913 alloclen + hh_len + 15, 1, 914 sk->sk_allocation); 915 if (unlikely(skb == NULL)) 916 err = -ENOBUFS; 917 } 918 if (skb == NULL) 919 goto error; 920 921 /* 922 * Fill in the control structures 923 */ 924 skb->ip_summed = csummode; 925 skb->csum = 0; 926 skb_reserve(skb, hh_len); 927 928 /* 929 * Find where to start putting bytes. 930 */ 931 data = skb_put(skb, fraglen); 932 skb->nh.raw = data + exthdrlen; 933 data += fragheaderlen; 934 skb->h.raw = data + exthdrlen; 935 936 if (fraggap) { 937 skb->csum = skb_copy_and_csum_bits( 938 skb_prev, maxfraglen, 939 data + transhdrlen, fraggap, 0); 940 skb_prev->csum = csum_sub(skb_prev->csum, 941 skb->csum); 942 data += fraggap; 943 pskb_trim_unique(skb_prev, maxfraglen); 944 } 945 946 copy = datalen - transhdrlen - fraggap; 947 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 948 err = -EFAULT; 949 kfree_skb(skb); 950 goto error; 951 } 952 953 offset += copy; 954 length -= datalen - fraggap; 955 transhdrlen = 0; 956 exthdrlen = 0; 957 csummode = CHECKSUM_NONE; 958 959 /* 960 * Put the packet on the pending queue. 961 */ 962 __skb_queue_tail(&sk->sk_write_queue, skb); 963 continue; 964 } 965 966 if (copy > length) 967 copy = length; 968 969 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 970 unsigned int off; 971 972 off = skb->len; 973 if (getfrag(from, skb_put(skb, copy), 974 offset, copy, off, skb) < 0) { 975 __skb_trim(skb, off); 976 err = -EFAULT; 977 goto error; 978 } 979 } else { 980 int i = skb_shinfo(skb)->nr_frags; 981 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 982 struct page *page = sk->sk_sndmsg_page; 983 int off = sk->sk_sndmsg_off; 984 unsigned int left; 985 986 if (page && (left = PAGE_SIZE - off) > 0) { 987 if (copy >= left) 988 copy = left; 989 if (page != frag->page) { 990 if (i == MAX_SKB_FRAGS) { 991 err = -EMSGSIZE; 992 goto error; 993 } 994 get_page(page); 995 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 996 frag = &skb_shinfo(skb)->frags[i]; 997 } 998 } else if (i < MAX_SKB_FRAGS) { 999 if (copy > PAGE_SIZE) 1000 copy = PAGE_SIZE; 1001 page = alloc_pages(sk->sk_allocation, 0); 1002 if (page == NULL) { 1003 err = -ENOMEM; 1004 goto error; 1005 } 1006 sk->sk_sndmsg_page = page; 1007 sk->sk_sndmsg_off = 0; 1008 1009 skb_fill_page_desc(skb, i, page, 0, 0); 1010 frag = &skb_shinfo(skb)->frags[i]; 1011 skb->truesize += PAGE_SIZE; 1012 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1013 } else { 1014 err = -EMSGSIZE; 1015 goto error; 1016 } 1017 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1018 err = -EFAULT; 1019 goto error; 1020 } 1021 sk->sk_sndmsg_off += copy; 1022 frag->size += copy; 1023 skb->len += copy; 1024 skb->data_len += copy; 1025 } 1026 offset += copy; 1027 length -= copy; 1028 } 1029 1030 return 0; 1031 1032error: 1033 inet->cork.length -= length; 1034 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1035 return err; 1036} 1037 1038ssize_t ip_append_page(struct sock *sk, struct page *page, 1039 int offset, size_t size, int flags) 1040{ 1041 struct inet_sock *inet = inet_sk(sk); 1042 struct sk_buff *skb; 1043 struct rtable *rt; 1044 struct ip_options *opt = NULL; 1045 int hh_len; 1046 int mtu; 1047 int len; 1048 int err; 1049 unsigned int maxfraglen, fragheaderlen, fraggap; 1050 1051 if (inet->hdrincl) 1052 return -EPERM; 1053 1054 if (flags&MSG_PROBE) 1055 return 0; 1056 1057 if (skb_queue_empty(&sk->sk_write_queue)) 1058 return -EINVAL; 1059 1060 rt = inet->cork.rt; 1061 if (inet->cork.flags & IPCORK_OPT) 1062 opt = inet->cork.opt; 1063 1064 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1065 return -EOPNOTSUPP; 1066 1067 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1068 mtu = inet->cork.fragsize; 1069 1070 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1071 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1072 1073 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1074 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1075 return -EMSGSIZE; 1076 } 1077 1078 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1079 return -EINVAL; 1080 1081 inet->cork.length += size; 1082 if ((sk->sk_protocol == IPPROTO_UDP) && 1083 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1084 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1085 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1086 } 1087 1088 1089 while (size > 0) { 1090 int i; 1091 1092 if (skb_is_gso(skb)) 1093 len = size; 1094 else { 1095 1096 /* Check if the remaining data fits into current packet. */ 1097 len = mtu - skb->len; 1098 if (len < size) 1099 len = maxfraglen - skb->len; 1100 } 1101 if (len <= 0) { 1102 struct sk_buff *skb_prev; 1103 char *data; 1104 struct iphdr *iph; 1105 int alloclen; 1106 1107 skb_prev = skb; 1108 fraggap = skb_prev->len - maxfraglen; 1109 1110 alloclen = fragheaderlen + hh_len + fraggap + 15; 1111 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1112 if (unlikely(!skb)) { 1113 err = -ENOBUFS; 1114 goto error; 1115 } 1116 1117 /* 1118 * Fill in the control structures 1119 */ 1120 skb->ip_summed = CHECKSUM_NONE; 1121 skb->csum = 0; 1122 skb_reserve(skb, hh_len); 1123 1124 /* 1125 * Find where to start putting bytes. 1126 */ 1127 data = skb_put(skb, fragheaderlen + fraggap); 1128 skb->nh.iph = iph = (struct iphdr *)data; 1129 data += fragheaderlen; 1130 skb->h.raw = data; 1131 1132 if (fraggap) { 1133 skb->csum = skb_copy_and_csum_bits( 1134 skb_prev, maxfraglen, 1135 data, fraggap, 0); 1136 skb_prev->csum = csum_sub(skb_prev->csum, 1137 skb->csum); 1138 pskb_trim_unique(skb_prev, maxfraglen); 1139 } 1140 1141 /* 1142 * Put the packet on the pending queue. 1143 */ 1144 __skb_queue_tail(&sk->sk_write_queue, skb); 1145 continue; 1146 } 1147 1148 i = skb_shinfo(skb)->nr_frags; 1149 if (len > size) 1150 len = size; 1151 if (skb_can_coalesce(skb, i, page, offset)) { 1152 skb_shinfo(skb)->frags[i-1].size += len; 1153 } else if (i < MAX_SKB_FRAGS) { 1154 get_page(page); 1155 skb_fill_page_desc(skb, i, page, offset, len); 1156 } else { 1157 err = -EMSGSIZE; 1158 goto error; 1159 } 1160 1161 if (skb->ip_summed == CHECKSUM_NONE) { 1162 __wsum csum; 1163 csum = csum_page(page, offset, len); 1164 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1165 } 1166 1167 skb->len += len; 1168 skb->data_len += len; 1169 offset += len; 1170 size -= len; 1171 } 1172 return 0; 1173 1174error: 1175 inet->cork.length -= size; 1176 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1177 return err; 1178} 1179 1180/* 1181 * Combined all pending IP fragments on the socket as one IP datagram 1182 * and push them out. 1183 */ 1184int ip_push_pending_frames(struct sock *sk) 1185{ 1186 struct sk_buff *skb, *tmp_skb; 1187 struct sk_buff **tail_skb; 1188 struct inet_sock *inet = inet_sk(sk); 1189 struct ip_options *opt = NULL; 1190 struct rtable *rt = inet->cork.rt; 1191 struct iphdr *iph; 1192 __be16 df = 0; 1193 __u8 ttl; 1194 int err = 0; 1195 1196 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1197 goto out; 1198 tail_skb = &(skb_shinfo(skb)->frag_list); 1199 1200 /* move skb->data to ip header from ext header */ 1201 if (skb->data < skb->nh.raw) 1202 __skb_pull(skb, skb->nh.raw - skb->data); 1203 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1204 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1205 *tail_skb = tmp_skb; 1206 tail_skb = &(tmp_skb->next); 1207 skb->len += tmp_skb->len; 1208 skb->data_len += tmp_skb->len; 1209 skb->truesize += tmp_skb->truesize; 1210 __sock_put(tmp_skb->sk); 1211 tmp_skb->destructor = NULL; 1212 tmp_skb->sk = NULL; 1213 } 1214 1215 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1216 * to fragment the frame generated here. No matter, what transforms 1217 * how transforms change size of the packet, it will come out. 1218 */ 1219 if (inet->pmtudisc != IP_PMTUDISC_DO) 1220 skb->local_df = 1; 1221 1222 /* DF bit is set when we want to see DF on outgoing frames. 1223 * If local_df is set too, we still allow to fragment this frame 1224 * locally. */ 1225 if (inet->pmtudisc == IP_PMTUDISC_DO || 1226 (skb->len <= dst_mtu(&rt->u.dst) && 1227 ip_dont_fragment(sk, &rt->u.dst))) 1228 df = htons(IP_DF); 1229 1230 if (inet->cork.flags & IPCORK_OPT) 1231 opt = inet->cork.opt; 1232 1233 if (rt->rt_type == RTN_MULTICAST) 1234 ttl = inet->mc_ttl; 1235 else 1236 ttl = ip_select_ttl(inet, &rt->u.dst); 1237 1238 iph = (struct iphdr *)skb->data; 1239 iph->version = 4; 1240 iph->ihl = 5; 1241 if (opt) { 1242 iph->ihl += opt->optlen>>2; 1243 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1244 } 1245 iph->tos = inet->tos; 1246 iph->tot_len = htons(skb->len); 1247 iph->frag_off = df; 1248 ip_select_ident(iph, &rt->u.dst, sk); 1249 iph->ttl = ttl; 1250 iph->protocol = sk->sk_protocol; 1251 iph->saddr = rt->rt_src; 1252 iph->daddr = rt->rt_dst; 1253 ip_send_check(iph); 1254 1255 skb->priority = sk->sk_priority; 1256 skb->dst = dst_clone(&rt->u.dst); 1257 1258 /* Netfilter gets whole the not fragmented skb. */ 1259 err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, 1260 skb->dst->dev, dst_output); 1261 if (err) { 1262 if (err > 0) 1263 err = inet->recverr ? net_xmit_errno(err) : 0; 1264 if (err) 1265 goto error; 1266 } 1267 1268out: 1269 inet->cork.flags &= ~IPCORK_OPT; 1270 kfree(inet->cork.opt); 1271 inet->cork.opt = NULL; 1272 if (inet->cork.rt) { 1273 ip_rt_put(inet->cork.rt); 1274 inet->cork.rt = NULL; 1275 } 1276 return err; 1277 1278error: 1279 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1280 goto out; 1281} 1282 1283/* 1284 * Throw away all pending data on the socket. 1285 */ 1286void ip_flush_pending_frames(struct sock *sk) 1287{ 1288 struct inet_sock *inet = inet_sk(sk); 1289 struct sk_buff *skb; 1290 1291 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1292 kfree_skb(skb); 1293 1294 inet->cork.flags &= ~IPCORK_OPT; 1295 kfree(inet->cork.opt); 1296 inet->cork.opt = NULL; 1297 if (inet->cork.rt) { 1298 ip_rt_put(inet->cork.rt); 1299 inet->cork.rt = NULL; 1300 } 1301} 1302 1303 1304/* 1305 * Fetch data from kernel space and fill in checksum if needed. 1306 */ 1307static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1308 int len, int odd, struct sk_buff *skb) 1309{ 1310 __wsum csum; 1311 1312 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1313 skb->csum = csum_block_add(skb->csum, csum, odd); 1314 return 0; 1315} 1316 1317/* 1318 * Generic function to send a packet as reply to another packet. 1319 * Used to send TCP resets so far. ICMP should use this function too. 1320 * 1321 * Should run single threaded per socket because it uses the sock 1322 * structure to pass arguments. 1323 * 1324 * LATER: switch from ip_build_xmit to ip_append_* 1325 */ 1326void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1327 unsigned int len) 1328{ 1329 struct inet_sock *inet = inet_sk(sk); 1330 struct { 1331 struct ip_options opt; 1332 char data[40]; 1333 } replyopts; 1334 struct ipcm_cookie ipc; 1335 __be32 daddr; 1336 struct rtable *rt = (struct rtable*)skb->dst; 1337 1338 if (ip_options_echo(&replyopts.opt, skb)) 1339 return; 1340 1341 daddr = ipc.addr = rt->rt_src; 1342 ipc.opt = NULL; 1343 1344 if (replyopts.opt.optlen) { 1345 ipc.opt = &replyopts.opt; 1346 1347 if (ipc.opt->srr) 1348 daddr = replyopts.opt.faddr; 1349 } 1350 1351 { 1352 struct flowi fl = { .nl_u = { .ip4_u = 1353 { .daddr = daddr, 1354 .saddr = rt->rt_spec_dst, 1355 .tos = RT_TOS(skb->nh.iph->tos) } }, 1356 /* Not quite clean, but right. */ 1357 .uli_u = { .ports = 1358 { .sport = skb->h.th->dest, 1359 .dport = skb->h.th->source } }, 1360 .proto = sk->sk_protocol }; 1361 security_skb_classify_flow(skb, &fl); 1362 if (ip_route_output_key(&rt, &fl)) 1363 return; 1364 } 1365 1366 /* And let IP do all the hard work. 1367 1368 This chunk is not reenterable, hence spinlock. 1369 Note that it uses the fact, that this function is called 1370 with locally disabled BH and that sk cannot be already spinlocked. 1371 */ 1372 bh_lock_sock(sk); 1373 inet->tos = skb->nh.iph->tos; 1374 sk->sk_priority = skb->priority; 1375 sk->sk_protocol = skb->nh.iph->protocol; 1376 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1377 &ipc, rt, MSG_DONTWAIT); 1378 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1379 if (arg->csumoffset >= 0) 1380 *((__sum16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum)); 1381 skb->ip_summed = CHECKSUM_NONE; 1382 ip_push_pending_frames(sk); 1383 } 1384 1385 bh_unlock_sock(sk); 1386 1387 ip_rt_put(rt); 1388} 1389 1390void __init ip_init(void) 1391{ 1392 ip_rt_init(); 1393 inet_initpeers(); 1394 1395#if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1396 igmp_mc_proc_init(); 1397#endif 1398} 1399 1400EXPORT_SYMBOL(ip_generic_getfrag); 1401EXPORT_SYMBOL(ip_queue_xmit); 1402EXPORT_SYMBOL(ip_send_check); 1403