ip_output.c revision 429f08e950a88cd826b203ea898c2f2d0f7db9de
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/mm.h> 53#include <linux/string.h> 54#include <linux/errno.h> 55#include <linux/highmem.h> 56 57#include <linux/socket.h> 58#include <linux/sockios.h> 59#include <linux/in.h> 60#include <linux/inet.h> 61#include <linux/netdevice.h> 62#include <linux/etherdevice.h> 63#include <linux/proc_fs.h> 64#include <linux/stat.h> 65#include <linux/init.h> 66 67#include <net/snmp.h> 68#include <net/ip.h> 69#include <net/protocol.h> 70#include <net/route.h> 71#include <net/xfrm.h> 72#include <linux/skbuff.h> 73#include <net/sock.h> 74#include <net/arp.h> 75#include <net/icmp.h> 76#include <net/checksum.h> 77#include <net/inetpeer.h> 78#include <linux/igmp.h> 79#include <linux/netfilter_ipv4.h> 80#include <linux/netfilter_bridge.h> 81#include <linux/mroute.h> 82#include <linux/netlink.h> 83#include <linux/tcp.h> 84 85int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; 86 87/* Generate a checksum for an outgoing IP datagram. */ 88__inline__ void ip_send_check(struct iphdr *iph) 89{ 90 iph->check = 0; 91 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 92} 93 94/* dev_loopback_xmit for use with netfilter. */ 95static int ip_dev_loopback_xmit(struct sk_buff *newskb) 96{ 97 skb_reset_mac_header(newskb); 98 __skb_pull(newskb, skb_network_offset(newskb)); 99 newskb->pkt_type = PACKET_LOOPBACK; 100 newskb->ip_summed = CHECKSUM_UNNECESSARY; 101 BUG_TRAP(newskb->dst); 102 netif_rx(newskb); 103 return 0; 104} 105 106static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) 107{ 108 int ttl = inet->uc_ttl; 109 110 if (ttl < 0) 111 ttl = dst_metric(dst, RTAX_HOPLIMIT); 112 return ttl; 113} 114 115/* 116 * Add an ip header to a skbuff and send it out. 117 * 118 */ 119int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 120 __be32 saddr, __be32 daddr, struct ip_options *opt) 121{ 122 struct inet_sock *inet = inet_sk(sk); 123 struct rtable *rt = (struct rtable *)skb->dst; 124 struct iphdr *iph; 125 126 /* Build the IP header. */ 127 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 128 skb_reset_network_header(skb); 129 iph = ip_hdr(skb); 130 iph->version = 4; 131 iph->ihl = 5; 132 iph->tos = inet->tos; 133 if (ip_dont_fragment(sk, &rt->u.dst)) 134 iph->frag_off = htons(IP_DF); 135 else 136 iph->frag_off = 0; 137 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 138 iph->daddr = rt->rt_dst; 139 iph->saddr = rt->rt_src; 140 iph->protocol = sk->sk_protocol; 141 iph->tot_len = htons(skb->len); 142 ip_select_ident(iph, &rt->u.dst, sk); 143 144 if (opt && opt->optlen) { 145 iph->ihl += opt->optlen>>2; 146 ip_options_build(skb, opt, daddr, rt, 0); 147 } 148 ip_send_check(iph); 149 150 skb->priority = sk->sk_priority; 151 152 /* Send it out. */ 153 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 154 dst_output); 155} 156 157EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); 158 159static inline int ip_finish_output2(struct sk_buff *skb) 160{ 161 struct dst_entry *dst = skb->dst; 162 struct rtable *rt = (struct rtable *)dst; 163 struct net_device *dev = dst->dev; 164 unsigned int hh_len = LL_RESERVED_SPACE(dev); 165 166 if (rt->rt_type == RTN_MULTICAST) 167 IP_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS); 168 else if (rt->rt_type == RTN_BROADCAST) 169 IP_INC_STATS(IPSTATS_MIB_OUTBCASTPKTS); 170 171 /* Be paranoid, rather than too clever. */ 172 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { 173 struct sk_buff *skb2; 174 175 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); 176 if (skb2 == NULL) { 177 kfree_skb(skb); 178 return -ENOMEM; 179 } 180 if (skb->sk) 181 skb_set_owner_w(skb2, skb->sk); 182 kfree_skb(skb); 183 skb = skb2; 184 } 185 186 if (dst->hh) 187 return neigh_hh_output(dst->hh, skb); 188 else if (dst->neighbour) 189 return dst->neighbour->output(skb); 190 191 if (net_ratelimit()) 192 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); 193 kfree_skb(skb); 194 return -EINVAL; 195} 196 197static inline int ip_skb_dst_mtu(struct sk_buff *skb) 198{ 199 struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL; 200 201 return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ? 202 skb->dst->dev->mtu : dst_mtu(skb->dst); 203} 204 205static int ip_finish_output(struct sk_buff *skb) 206{ 207#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 208 /* Policy lookup after SNAT yielded a new policy */ 209 if (skb->dst->xfrm != NULL) { 210 IPCB(skb)->flags |= IPSKB_REROUTED; 211 return dst_output(skb); 212 } 213#endif 214 if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb)) 215 return ip_fragment(skb, ip_finish_output2); 216 else 217 return ip_finish_output2(skb); 218} 219 220int ip_mc_output(struct sk_buff *skb) 221{ 222 struct sock *sk = skb->sk; 223 struct rtable *rt = (struct rtable*)skb->dst; 224 struct net_device *dev = rt->u.dst.dev; 225 226 /* 227 * If the indicated interface is up and running, send the packet. 228 */ 229 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 230 231 skb->dev = dev; 232 skb->protocol = htons(ETH_P_IP); 233 234 /* 235 * Multicasts are looped back for other local users 236 */ 237 238 if (rt->rt_flags&RTCF_MULTICAST) { 239 if ((!sk || inet_sk(sk)->mc_loop) 240#ifdef CONFIG_IP_MROUTE 241 /* Small optimization: do not loopback not local frames, 242 which returned after forwarding; they will be dropped 243 by ip_mr_input in any case. 244 Note, that local frames are looped back to be delivered 245 to local recipients. 246 247 This check is duplicated in ip_mr_input at the moment. 248 */ 249 && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) 250#endif 251 ) { 252 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 253 if (newskb) 254 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 255 newskb->dev, 256 ip_dev_loopback_xmit); 257 } 258 259 /* Multicasts with ttl 0 must not go beyond the host */ 260 261 if (ip_hdr(skb)->ttl == 0) { 262 kfree_skb(skb); 263 return 0; 264 } 265 } 266 267 if (rt->rt_flags&RTCF_BROADCAST) { 268 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 269 if (newskb) 270 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 271 newskb->dev, ip_dev_loopback_xmit); 272 } 273 274 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev, 275 ip_finish_output, 276 !(IPCB(skb)->flags & IPSKB_REROUTED)); 277} 278 279int ip_output(struct sk_buff *skb) 280{ 281 struct net_device *dev = skb->dst->dev; 282 283 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 284 285 skb->dev = dev; 286 skb->protocol = htons(ETH_P_IP); 287 288 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, 289 ip_finish_output, 290 !(IPCB(skb)->flags & IPSKB_REROUTED)); 291} 292 293int ip_queue_xmit(struct sk_buff *skb, int ipfragok) 294{ 295 struct sock *sk = skb->sk; 296 struct inet_sock *inet = inet_sk(sk); 297 struct ip_options *opt = inet->opt; 298 struct rtable *rt; 299 struct iphdr *iph; 300 301 /* Skip all of this if the packet is already routed, 302 * f.e. by something like SCTP. 303 */ 304 rt = (struct rtable *) skb->dst; 305 if (rt != NULL) 306 goto packet_routed; 307 308 /* Make sure we can route this packet. */ 309 rt = (struct rtable *)__sk_dst_check(sk, 0); 310 if (rt == NULL) { 311 __be32 daddr; 312 313 /* Use correct destination address if we have options. */ 314 daddr = inet->daddr; 315 if(opt && opt->srr) 316 daddr = opt->faddr; 317 318 { 319 struct flowi fl = { .oif = sk->sk_bound_dev_if, 320 .nl_u = { .ip4_u = 321 { .daddr = daddr, 322 .saddr = inet->saddr, 323 .tos = RT_CONN_FLAGS(sk) } }, 324 .proto = sk->sk_protocol, 325 .uli_u = { .ports = 326 { .sport = inet->sport, 327 .dport = inet->dport } } }; 328 329 /* If this fails, retransmit mechanism of transport layer will 330 * keep trying until route appears or the connection times 331 * itself out. 332 */ 333 security_sk_classify_flow(sk, &fl); 334 if (ip_route_output_flow(&rt, &fl, sk, 0)) 335 goto no_route; 336 } 337 sk_setup_caps(sk, &rt->u.dst); 338 } 339 skb->dst = dst_clone(&rt->u.dst); 340 341packet_routed: 342 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) 343 goto no_route; 344 345 /* OK, we know where to send it, allocate and build IP header. */ 346 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 347 skb_reset_network_header(skb); 348 iph = ip_hdr(skb); 349 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); 350 iph->tot_len = htons(skb->len); 351 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) 352 iph->frag_off = htons(IP_DF); 353 else 354 iph->frag_off = 0; 355 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 356 iph->protocol = sk->sk_protocol; 357 iph->saddr = rt->rt_src; 358 iph->daddr = rt->rt_dst; 359 /* Transport layer set skb->h.foo itself. */ 360 361 if (opt && opt->optlen) { 362 iph->ihl += opt->optlen >> 2; 363 ip_options_build(skb, opt, inet->daddr, rt, 0); 364 } 365 366 ip_select_ident_more(iph, &rt->u.dst, sk, 367 (skb_shinfo(skb)->gso_segs ?: 1) - 1); 368 369 /* Add an IP checksum. */ 370 ip_send_check(iph); 371 372 skb->priority = sk->sk_priority; 373 374 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 375 dst_output); 376 377no_route: 378 IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); 379 kfree_skb(skb); 380 return -EHOSTUNREACH; 381} 382 383 384static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) 385{ 386 to->pkt_type = from->pkt_type; 387 to->priority = from->priority; 388 to->protocol = from->protocol; 389 dst_release(to->dst); 390 to->dst = dst_clone(from->dst); 391 to->dev = from->dev; 392 to->mark = from->mark; 393 394 /* Copy the flags to each fragment. */ 395 IPCB(to)->flags = IPCB(from)->flags; 396 397#ifdef CONFIG_NET_SCHED 398 to->tc_index = from->tc_index; 399#endif 400 nf_copy(to, from); 401#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ 402 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) 403 to->nf_trace = from->nf_trace; 404#endif 405#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 406 to->ipvs_property = from->ipvs_property; 407#endif 408 skb_copy_secmark(to, from); 409} 410 411/* 412 * This IP datagram is too large to be sent in one piece. Break it up into 413 * smaller pieces (each of size equal to IP header plus 414 * a block of the data of the original IP data part) that will yet fit in a 415 * single device frame, and queue such a frame for sending. 416 */ 417 418int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) 419{ 420 struct iphdr *iph; 421 int raw = 0; 422 int ptr; 423 struct net_device *dev; 424 struct sk_buff *skb2; 425 unsigned int mtu, hlen, left, len, ll_rs, pad; 426 int offset; 427 __be16 not_last_frag; 428 struct rtable *rt = (struct rtable*)skb->dst; 429 int err = 0; 430 431 dev = rt->u.dst.dev; 432 433 /* 434 * Point into the IP datagram header. 435 */ 436 437 iph = ip_hdr(skb); 438 439 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { 440 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 441 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 442 htonl(ip_skb_dst_mtu(skb))); 443 kfree_skb(skb); 444 return -EMSGSIZE; 445 } 446 447 /* 448 * Setup starting values. 449 */ 450 451 hlen = iph->ihl * 4; 452 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 453 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 454 455 /* When frag_list is given, use it. First, check its validity: 456 * some transformers could create wrong frag_list or break existing 457 * one, it is not prohibited. In this case fall back to copying. 458 * 459 * LATER: this step can be merged to real generation of fragments, 460 * we can switch to copy when see the first bad fragment. 461 */ 462 if (skb_shinfo(skb)->frag_list) { 463 struct sk_buff *frag; 464 int first_len = skb_pagelen(skb); 465 466 if (first_len - hlen > mtu || 467 ((first_len - hlen) & 7) || 468 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 469 skb_cloned(skb)) 470 goto slow_path; 471 472 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 473 /* Correct geometry. */ 474 if (frag->len > mtu || 475 ((frag->len & 7) && frag->next) || 476 skb_headroom(frag) < hlen) 477 goto slow_path; 478 479 /* Partially cloned skb? */ 480 if (skb_shared(frag)) 481 goto slow_path; 482 483 BUG_ON(frag->sk); 484 if (skb->sk) { 485 sock_hold(skb->sk); 486 frag->sk = skb->sk; 487 frag->destructor = sock_wfree; 488 skb->truesize -= frag->truesize; 489 } 490 } 491 492 /* Everything is OK. Generate! */ 493 494 err = 0; 495 offset = 0; 496 frag = skb_shinfo(skb)->frag_list; 497 skb_shinfo(skb)->frag_list = NULL; 498 skb->data_len = first_len - skb_headlen(skb); 499 skb->len = first_len; 500 iph->tot_len = htons(first_len); 501 iph->frag_off = htons(IP_MF); 502 ip_send_check(iph); 503 504 for (;;) { 505 /* Prepare header of the next frame, 506 * before previous one went down. */ 507 if (frag) { 508 frag->ip_summed = CHECKSUM_NONE; 509 skb_reset_transport_header(frag); 510 __skb_push(frag, hlen); 511 skb_reset_network_header(frag); 512 memcpy(skb_network_header(frag), iph, hlen); 513 iph = ip_hdr(frag); 514 iph->tot_len = htons(frag->len); 515 ip_copy_metadata(frag, skb); 516 if (offset == 0) 517 ip_options_fragment(frag); 518 offset += skb->len - hlen; 519 iph->frag_off = htons(offset>>3); 520 if (frag->next != NULL) 521 iph->frag_off |= htons(IP_MF); 522 /* Ready, complete checksum */ 523 ip_send_check(iph); 524 } 525 526 err = output(skb); 527 528 if (!err) 529 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 530 if (err || !frag) 531 break; 532 533 skb = frag; 534 frag = skb->next; 535 skb->next = NULL; 536 } 537 538 if (err == 0) { 539 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 540 return 0; 541 } 542 543 while (frag) { 544 skb = frag->next; 545 kfree_skb(frag); 546 frag = skb; 547 } 548 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 549 return err; 550 } 551 552slow_path: 553 left = skb->len - hlen; /* Space per frame */ 554 ptr = raw + hlen; /* Where to start from */ 555 556 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 557 * we need to make room for the encapsulating header 558 */ 559 pad = nf_bridge_pad(skb); 560 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad); 561 mtu -= pad; 562 563 /* 564 * Fragment the datagram. 565 */ 566 567 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 568 not_last_frag = iph->frag_off & htons(IP_MF); 569 570 /* 571 * Keep copying data until we run out. 572 */ 573 574 while (left > 0) { 575 len = left; 576 /* IF: it doesn't fit, use 'mtu' - the data space left */ 577 if (len > mtu) 578 len = mtu; 579 /* IF: we are not sending upto and including the packet end 580 then align the next start on an eight byte boundary */ 581 if (len < left) { 582 len &= ~7; 583 } 584 /* 585 * Allocate buffer. 586 */ 587 588 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 589 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 590 err = -ENOMEM; 591 goto fail; 592 } 593 594 /* 595 * Set up data on packet 596 */ 597 598 ip_copy_metadata(skb2, skb); 599 skb_reserve(skb2, ll_rs); 600 skb_put(skb2, len + hlen); 601 skb_reset_network_header(skb2); 602 skb2->transport_header = skb2->network_header + hlen; 603 604 /* 605 * Charge the memory for the fragment to any owner 606 * it might possess 607 */ 608 609 if (skb->sk) 610 skb_set_owner_w(skb2, skb->sk); 611 612 /* 613 * Copy the packet header into the new buffer. 614 */ 615 616 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); 617 618 /* 619 * Copy a block of the IP datagram. 620 */ 621 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) 622 BUG(); 623 left -= len; 624 625 /* 626 * Fill in the new header fields. 627 */ 628 iph = ip_hdr(skb2); 629 iph->frag_off = htons((offset >> 3)); 630 631 /* ANK: dirty, but effective trick. Upgrade options only if 632 * the segment to be fragmented was THE FIRST (otherwise, 633 * options are already fixed) and make it ONCE 634 * on the initial skb, so that all the following fragments 635 * will inherit fixed options. 636 */ 637 if (offset == 0) 638 ip_options_fragment(skb); 639 640 /* 641 * Added AC : If we are fragmenting a fragment that's not the 642 * last fragment then keep MF on each bit 643 */ 644 if (left > 0 || not_last_frag) 645 iph->frag_off |= htons(IP_MF); 646 ptr += len; 647 offset += len; 648 649 /* 650 * Put this fragment into the sending queue. 651 */ 652 iph->tot_len = htons(len + hlen); 653 654 ip_send_check(iph); 655 656 err = output(skb2); 657 if (err) 658 goto fail; 659 660 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 661 } 662 kfree_skb(skb); 663 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 664 return err; 665 666fail: 667 kfree_skb(skb); 668 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 669 return err; 670} 671 672EXPORT_SYMBOL(ip_fragment); 673 674int 675ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 676{ 677 struct iovec *iov = from; 678 679 if (skb->ip_summed == CHECKSUM_PARTIAL) { 680 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 681 return -EFAULT; 682 } else { 683 __wsum csum = 0; 684 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 685 return -EFAULT; 686 skb->csum = csum_block_add(skb->csum, csum, odd); 687 } 688 return 0; 689} 690 691static inline __wsum 692csum_page(struct page *page, int offset, int copy) 693{ 694 char *kaddr; 695 __wsum csum; 696 kaddr = kmap(page); 697 csum = csum_partial(kaddr + offset, copy, 0); 698 kunmap(page); 699 return csum; 700} 701 702static inline int ip_ufo_append_data(struct sock *sk, 703 int getfrag(void *from, char *to, int offset, int len, 704 int odd, struct sk_buff *skb), 705 void *from, int length, int hh_len, int fragheaderlen, 706 int transhdrlen, int mtu,unsigned int flags) 707{ 708 struct sk_buff *skb; 709 int err; 710 711 /* There is support for UDP fragmentation offload by network 712 * device, so create one single skb packet containing complete 713 * udp datagram 714 */ 715 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 716 skb = sock_alloc_send_skb(sk, 717 hh_len + fragheaderlen + transhdrlen + 20, 718 (flags & MSG_DONTWAIT), &err); 719 720 if (skb == NULL) 721 return err; 722 723 /* reserve space for Hardware header */ 724 skb_reserve(skb, hh_len); 725 726 /* create space for UDP/IP header */ 727 skb_put(skb,fragheaderlen + transhdrlen); 728 729 /* initialize network header pointer */ 730 skb_reset_network_header(skb); 731 732 /* initialize protocol header pointer */ 733 skb->transport_header = skb->network_header + fragheaderlen; 734 735 skb->ip_summed = CHECKSUM_PARTIAL; 736 skb->csum = 0; 737 sk->sk_sndmsg_off = 0; 738 } 739 740 err = skb_append_datato_frags(sk,skb, getfrag, from, 741 (length - transhdrlen)); 742 if (!err) { 743 /* specify the length of each IP datagram fragment*/ 744 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 745 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 746 __skb_queue_tail(&sk->sk_write_queue, skb); 747 748 return 0; 749 } 750 /* There is not enough support do UFO , 751 * so follow normal path 752 */ 753 kfree_skb(skb); 754 return err; 755} 756 757/* 758 * ip_append_data() and ip_append_page() can make one large IP datagram 759 * from many pieces of data. Each pieces will be holded on the socket 760 * until ip_push_pending_frames() is called. Each piece can be a page 761 * or non-page data. 762 * 763 * Not only UDP, other transport protocols - e.g. raw sockets - can use 764 * this interface potentially. 765 * 766 * LATER: length must be adjusted by pad at tail, when it is required. 767 */ 768int ip_append_data(struct sock *sk, 769 int getfrag(void *from, char *to, int offset, int len, 770 int odd, struct sk_buff *skb), 771 void *from, int length, int transhdrlen, 772 struct ipcm_cookie *ipc, struct rtable *rt, 773 unsigned int flags) 774{ 775 struct inet_sock *inet = inet_sk(sk); 776 struct sk_buff *skb; 777 778 struct ip_options *opt = NULL; 779 int hh_len; 780 int exthdrlen; 781 int mtu; 782 int copy; 783 int err; 784 int offset = 0; 785 unsigned int maxfraglen, fragheaderlen; 786 int csummode = CHECKSUM_NONE; 787 788 if (flags&MSG_PROBE) 789 return 0; 790 791 if (skb_queue_empty(&sk->sk_write_queue)) { 792 /* 793 * setup for corking. 794 */ 795 opt = ipc->opt; 796 if (opt) { 797 if (inet->cork.opt == NULL) { 798 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 799 if (unlikely(inet->cork.opt == NULL)) 800 return -ENOBUFS; 801 } 802 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 803 inet->cork.flags |= IPCORK_OPT; 804 inet->cork.addr = ipc->addr; 805 } 806 dst_hold(&rt->u.dst); 807 inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? 808 rt->u.dst.dev->mtu : 809 dst_mtu(rt->u.dst.path); 810 inet->cork.rt = rt; 811 inet->cork.length = 0; 812 sk->sk_sndmsg_page = NULL; 813 sk->sk_sndmsg_off = 0; 814 if ((exthdrlen = rt->u.dst.header_len) != 0) { 815 length += exthdrlen; 816 transhdrlen += exthdrlen; 817 } 818 } else { 819 rt = inet->cork.rt; 820 if (inet->cork.flags & IPCORK_OPT) 821 opt = inet->cork.opt; 822 823 transhdrlen = 0; 824 exthdrlen = 0; 825 mtu = inet->cork.fragsize; 826 } 827 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 828 829 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 830 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 831 832 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 833 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 834 return -EMSGSIZE; 835 } 836 837 /* 838 * transhdrlen > 0 means that this is the first fragment and we wish 839 * it won't be fragmented in the future. 840 */ 841 if (transhdrlen && 842 length + fragheaderlen <= mtu && 843 rt->u.dst.dev->features & NETIF_F_V4_CSUM && 844 !exthdrlen) 845 csummode = CHECKSUM_PARTIAL; 846 847 inet->cork.length += length; 848 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 849 (rt->u.dst.dev->features & NETIF_F_UFO)) { 850 851 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 852 fragheaderlen, transhdrlen, mtu, 853 flags); 854 if (err) 855 goto error; 856 return 0; 857 } 858 859 /* So, what's going on in the loop below? 860 * 861 * We use calculated fragment length to generate chained skb, 862 * each of segments is IP fragment ready for sending to network after 863 * adding appropriate IP header. 864 */ 865 866 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 867 goto alloc_new_skb; 868 869 while (length > 0) { 870 /* Check if the remaining data fits into current packet. */ 871 copy = mtu - skb->len; 872 if (copy < length) 873 copy = maxfraglen - skb->len; 874 if (copy <= 0) { 875 char *data; 876 unsigned int datalen; 877 unsigned int fraglen; 878 unsigned int fraggap; 879 unsigned int alloclen; 880 struct sk_buff *skb_prev; 881alloc_new_skb: 882 skb_prev = skb; 883 if (skb_prev) 884 fraggap = skb_prev->len - maxfraglen; 885 else 886 fraggap = 0; 887 888 /* 889 * If remaining data exceeds the mtu, 890 * we know we need more fragment(s). 891 */ 892 datalen = length + fraggap; 893 if (datalen > mtu - fragheaderlen) 894 datalen = maxfraglen - fragheaderlen; 895 fraglen = datalen + fragheaderlen; 896 897 if ((flags & MSG_MORE) && 898 !(rt->u.dst.dev->features&NETIF_F_SG)) 899 alloclen = mtu; 900 else 901 alloclen = datalen + fragheaderlen; 902 903 /* The last fragment gets additional space at tail. 904 * Note, with MSG_MORE we overallocate on fragments, 905 * because we have no idea what fragment will be 906 * the last. 907 */ 908 if (datalen == length + fraggap) 909 alloclen += rt->u.dst.trailer_len; 910 911 if (transhdrlen) { 912 skb = sock_alloc_send_skb(sk, 913 alloclen + hh_len + 15, 914 (flags & MSG_DONTWAIT), &err); 915 } else { 916 skb = NULL; 917 if (atomic_read(&sk->sk_wmem_alloc) <= 918 2 * sk->sk_sndbuf) 919 skb = sock_wmalloc(sk, 920 alloclen + hh_len + 15, 1, 921 sk->sk_allocation); 922 if (unlikely(skb == NULL)) 923 err = -ENOBUFS; 924 } 925 if (skb == NULL) 926 goto error; 927 928 /* 929 * Fill in the control structures 930 */ 931 skb->ip_summed = csummode; 932 skb->csum = 0; 933 skb_reserve(skb, hh_len); 934 935 /* 936 * Find where to start putting bytes. 937 */ 938 data = skb_put(skb, fraglen); 939 skb_set_network_header(skb, exthdrlen); 940 skb->transport_header = (skb->network_header + 941 fragheaderlen); 942 data += fragheaderlen; 943 944 if (fraggap) { 945 skb->csum = skb_copy_and_csum_bits( 946 skb_prev, maxfraglen, 947 data + transhdrlen, fraggap, 0); 948 skb_prev->csum = csum_sub(skb_prev->csum, 949 skb->csum); 950 data += fraggap; 951 pskb_trim_unique(skb_prev, maxfraglen); 952 } 953 954 copy = datalen - transhdrlen - fraggap; 955 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 956 err = -EFAULT; 957 kfree_skb(skb); 958 goto error; 959 } 960 961 offset += copy; 962 length -= datalen - fraggap; 963 transhdrlen = 0; 964 exthdrlen = 0; 965 csummode = CHECKSUM_NONE; 966 967 /* 968 * Put the packet on the pending queue. 969 */ 970 __skb_queue_tail(&sk->sk_write_queue, skb); 971 continue; 972 } 973 974 if (copy > length) 975 copy = length; 976 977 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 978 unsigned int off; 979 980 off = skb->len; 981 if (getfrag(from, skb_put(skb, copy), 982 offset, copy, off, skb) < 0) { 983 __skb_trim(skb, off); 984 err = -EFAULT; 985 goto error; 986 } 987 } else { 988 int i = skb_shinfo(skb)->nr_frags; 989 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 990 struct page *page = sk->sk_sndmsg_page; 991 int off = sk->sk_sndmsg_off; 992 unsigned int left; 993 994 if (page && (left = PAGE_SIZE - off) > 0) { 995 if (copy >= left) 996 copy = left; 997 if (page != frag->page) { 998 if (i == MAX_SKB_FRAGS) { 999 err = -EMSGSIZE; 1000 goto error; 1001 } 1002 get_page(page); 1003 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1004 frag = &skb_shinfo(skb)->frags[i]; 1005 } 1006 } else if (i < MAX_SKB_FRAGS) { 1007 if (copy > PAGE_SIZE) 1008 copy = PAGE_SIZE; 1009 page = alloc_pages(sk->sk_allocation, 0); 1010 if (page == NULL) { 1011 err = -ENOMEM; 1012 goto error; 1013 } 1014 sk->sk_sndmsg_page = page; 1015 sk->sk_sndmsg_off = 0; 1016 1017 skb_fill_page_desc(skb, i, page, 0, 0); 1018 frag = &skb_shinfo(skb)->frags[i]; 1019 skb->truesize += PAGE_SIZE; 1020 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1021 } else { 1022 err = -EMSGSIZE; 1023 goto error; 1024 } 1025 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1026 err = -EFAULT; 1027 goto error; 1028 } 1029 sk->sk_sndmsg_off += copy; 1030 frag->size += copy; 1031 skb->len += copy; 1032 skb->data_len += copy; 1033 } 1034 offset += copy; 1035 length -= copy; 1036 } 1037 1038 return 0; 1039 1040error: 1041 inet->cork.length -= length; 1042 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1043 return err; 1044} 1045 1046ssize_t ip_append_page(struct sock *sk, struct page *page, 1047 int offset, size_t size, int flags) 1048{ 1049 struct inet_sock *inet = inet_sk(sk); 1050 struct sk_buff *skb; 1051 struct rtable *rt; 1052 struct ip_options *opt = NULL; 1053 int hh_len; 1054 int mtu; 1055 int len; 1056 int err; 1057 unsigned int maxfraglen, fragheaderlen, fraggap; 1058 1059 if (inet->hdrincl) 1060 return -EPERM; 1061 1062 if (flags&MSG_PROBE) 1063 return 0; 1064 1065 if (skb_queue_empty(&sk->sk_write_queue)) 1066 return -EINVAL; 1067 1068 rt = inet->cork.rt; 1069 if (inet->cork.flags & IPCORK_OPT) 1070 opt = inet->cork.opt; 1071 1072 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1073 return -EOPNOTSUPP; 1074 1075 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1076 mtu = inet->cork.fragsize; 1077 1078 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1079 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1080 1081 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1082 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1083 return -EMSGSIZE; 1084 } 1085 1086 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1087 return -EINVAL; 1088 1089 inet->cork.length += size; 1090 if ((sk->sk_protocol == IPPROTO_UDP) && 1091 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1092 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1093 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1094 } 1095 1096 1097 while (size > 0) { 1098 int i; 1099 1100 if (skb_is_gso(skb)) 1101 len = size; 1102 else { 1103 1104 /* Check if the remaining data fits into current packet. */ 1105 len = mtu - skb->len; 1106 if (len < size) 1107 len = maxfraglen - skb->len; 1108 } 1109 if (len <= 0) { 1110 struct sk_buff *skb_prev; 1111 int alloclen; 1112 1113 skb_prev = skb; 1114 fraggap = skb_prev->len - maxfraglen; 1115 1116 alloclen = fragheaderlen + hh_len + fraggap + 15; 1117 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1118 if (unlikely(!skb)) { 1119 err = -ENOBUFS; 1120 goto error; 1121 } 1122 1123 /* 1124 * Fill in the control structures 1125 */ 1126 skb->ip_summed = CHECKSUM_NONE; 1127 skb->csum = 0; 1128 skb_reserve(skb, hh_len); 1129 1130 /* 1131 * Find where to start putting bytes. 1132 */ 1133 skb_put(skb, fragheaderlen + fraggap); 1134 skb_reset_network_header(skb); 1135 skb->transport_header = (skb->network_header + 1136 fragheaderlen); 1137 if (fraggap) { 1138 skb->csum = skb_copy_and_csum_bits(skb_prev, 1139 maxfraglen, 1140 skb_transport_header(skb), 1141 fraggap, 0); 1142 skb_prev->csum = csum_sub(skb_prev->csum, 1143 skb->csum); 1144 pskb_trim_unique(skb_prev, maxfraglen); 1145 } 1146 1147 /* 1148 * Put the packet on the pending queue. 1149 */ 1150 __skb_queue_tail(&sk->sk_write_queue, skb); 1151 continue; 1152 } 1153 1154 i = skb_shinfo(skb)->nr_frags; 1155 if (len > size) 1156 len = size; 1157 if (skb_can_coalesce(skb, i, page, offset)) { 1158 skb_shinfo(skb)->frags[i-1].size += len; 1159 } else if (i < MAX_SKB_FRAGS) { 1160 get_page(page); 1161 skb_fill_page_desc(skb, i, page, offset, len); 1162 } else { 1163 err = -EMSGSIZE; 1164 goto error; 1165 } 1166 1167 if (skb->ip_summed == CHECKSUM_NONE) { 1168 __wsum csum; 1169 csum = csum_page(page, offset, len); 1170 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1171 } 1172 1173 skb->len += len; 1174 skb->data_len += len; 1175 offset += len; 1176 size -= len; 1177 } 1178 return 0; 1179 1180error: 1181 inet->cork.length -= size; 1182 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1183 return err; 1184} 1185 1186static void ip_cork_release(struct inet_sock *inet) 1187{ 1188 inet->cork.flags &= ~IPCORK_OPT; 1189 kfree(inet->cork.opt); 1190 inet->cork.opt = NULL; 1191 if (inet->cork.rt) { 1192 ip_rt_put(inet->cork.rt); 1193 inet->cork.rt = NULL; 1194 } 1195} 1196 1197/* 1198 * Combined all pending IP fragments on the socket as one IP datagram 1199 * and push them out. 1200 */ 1201int ip_push_pending_frames(struct sock *sk) 1202{ 1203 struct sk_buff *skb, *tmp_skb; 1204 struct sk_buff **tail_skb; 1205 struct inet_sock *inet = inet_sk(sk); 1206 struct ip_options *opt = NULL; 1207 struct rtable *rt = inet->cork.rt; 1208 struct iphdr *iph; 1209 __be16 df = 0; 1210 __u8 ttl; 1211 int err = 0; 1212 1213 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1214 goto out; 1215 tail_skb = &(skb_shinfo(skb)->frag_list); 1216 1217 /* move skb->data to ip header from ext header */ 1218 if (skb->data < skb_network_header(skb)) 1219 __skb_pull(skb, skb_network_offset(skb)); 1220 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1221 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1222 *tail_skb = tmp_skb; 1223 tail_skb = &(tmp_skb->next); 1224 skb->len += tmp_skb->len; 1225 skb->data_len += tmp_skb->len; 1226 skb->truesize += tmp_skb->truesize; 1227 __sock_put(tmp_skb->sk); 1228 tmp_skb->destructor = NULL; 1229 tmp_skb->sk = NULL; 1230 } 1231 1232 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1233 * to fragment the frame generated here. No matter, what transforms 1234 * how transforms change size of the packet, it will come out. 1235 */ 1236 if (inet->pmtudisc < IP_PMTUDISC_DO) 1237 skb->local_df = 1; 1238 1239 /* DF bit is set when we want to see DF on outgoing frames. 1240 * If local_df is set too, we still allow to fragment this frame 1241 * locally. */ 1242 if (inet->pmtudisc >= IP_PMTUDISC_DO || 1243 (skb->len <= dst_mtu(&rt->u.dst) && 1244 ip_dont_fragment(sk, &rt->u.dst))) 1245 df = htons(IP_DF); 1246 1247 if (inet->cork.flags & IPCORK_OPT) 1248 opt = inet->cork.opt; 1249 1250 if (rt->rt_type == RTN_MULTICAST) 1251 ttl = inet->mc_ttl; 1252 else 1253 ttl = ip_select_ttl(inet, &rt->u.dst); 1254 1255 iph = (struct iphdr *)skb->data; 1256 iph->version = 4; 1257 iph->ihl = 5; 1258 if (opt) { 1259 iph->ihl += opt->optlen>>2; 1260 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1261 } 1262 iph->tos = inet->tos; 1263 iph->tot_len = htons(skb->len); 1264 iph->frag_off = df; 1265 ip_select_ident(iph, &rt->u.dst, sk); 1266 iph->ttl = ttl; 1267 iph->protocol = sk->sk_protocol; 1268 iph->saddr = rt->rt_src; 1269 iph->daddr = rt->rt_dst; 1270 ip_send_check(iph); 1271 1272 skb->priority = sk->sk_priority; 1273 skb->dst = dst_clone(&rt->u.dst); 1274 1275 if (iph->protocol == IPPROTO_ICMP) 1276 icmp_out_count(((struct icmphdr *) 1277 skb_transport_header(skb))->type); 1278 1279 /* Netfilter gets whole the not fragmented skb. */ 1280 err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, 1281 skb->dst->dev, dst_output); 1282 if (err) { 1283 if (err > 0) 1284 err = inet->recverr ? net_xmit_errno(err) : 0; 1285 if (err) 1286 goto error; 1287 } 1288 1289out: 1290 ip_cork_release(inet); 1291 return err; 1292 1293error: 1294 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1295 goto out; 1296} 1297 1298/* 1299 * Throw away all pending data on the socket. 1300 */ 1301void ip_flush_pending_frames(struct sock *sk) 1302{ 1303 struct sk_buff *skb; 1304 1305 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1306 kfree_skb(skb); 1307 1308 ip_cork_release(inet_sk(sk)); 1309} 1310 1311 1312/* 1313 * Fetch data from kernel space and fill in checksum if needed. 1314 */ 1315static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1316 int len, int odd, struct sk_buff *skb) 1317{ 1318 __wsum csum; 1319 1320 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1321 skb->csum = csum_block_add(skb->csum, csum, odd); 1322 return 0; 1323} 1324 1325/* 1326 * Generic function to send a packet as reply to another packet. 1327 * Used to send TCP resets so far. ICMP should use this function too. 1328 * 1329 * Should run single threaded per socket because it uses the sock 1330 * structure to pass arguments. 1331 * 1332 * LATER: switch from ip_build_xmit to ip_append_* 1333 */ 1334void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1335 unsigned int len) 1336{ 1337 struct inet_sock *inet = inet_sk(sk); 1338 struct { 1339 struct ip_options opt; 1340 char data[40]; 1341 } replyopts; 1342 struct ipcm_cookie ipc; 1343 __be32 daddr; 1344 struct rtable *rt = (struct rtable*)skb->dst; 1345 1346 if (ip_options_echo(&replyopts.opt, skb)) 1347 return; 1348 1349 daddr = ipc.addr = rt->rt_src; 1350 ipc.opt = NULL; 1351 1352 if (replyopts.opt.optlen) { 1353 ipc.opt = &replyopts.opt; 1354 1355 if (ipc.opt->srr) 1356 daddr = replyopts.opt.faddr; 1357 } 1358 1359 { 1360 struct flowi fl = { .oif = arg->bound_dev_if, 1361 .nl_u = { .ip4_u = 1362 { .daddr = daddr, 1363 .saddr = rt->rt_spec_dst, 1364 .tos = RT_TOS(ip_hdr(skb)->tos) } }, 1365 /* Not quite clean, but right. */ 1366 .uli_u = { .ports = 1367 { .sport = tcp_hdr(skb)->dest, 1368 .dport = tcp_hdr(skb)->source } }, 1369 .proto = sk->sk_protocol }; 1370 security_skb_classify_flow(skb, &fl); 1371 if (ip_route_output_key(&rt, &fl)) 1372 return; 1373 } 1374 1375 /* And let IP do all the hard work. 1376 1377 This chunk is not reenterable, hence spinlock. 1378 Note that it uses the fact, that this function is called 1379 with locally disabled BH and that sk cannot be already spinlocked. 1380 */ 1381 bh_lock_sock(sk); 1382 inet->tos = ip_hdr(skb)->tos; 1383 sk->sk_priority = skb->priority; 1384 sk->sk_protocol = ip_hdr(skb)->protocol; 1385 sk->sk_bound_dev_if = arg->bound_dev_if; 1386 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1387 &ipc, rt, MSG_DONTWAIT); 1388 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1389 if (arg->csumoffset >= 0) 1390 *((__sum16 *)skb_transport_header(skb) + 1391 arg->csumoffset) = csum_fold(csum_add(skb->csum, 1392 arg->csum)); 1393 skb->ip_summed = CHECKSUM_NONE; 1394 ip_push_pending_frames(sk); 1395 } 1396 1397 bh_unlock_sock(sk); 1398 1399 ip_rt_put(rt); 1400} 1401 1402void __init ip_init(void) 1403{ 1404 ip_rt_init(); 1405 inet_initpeers(); 1406 1407#if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1408 igmp_mc_proc_init(); 1409#endif 1410} 1411 1412EXPORT_SYMBOL(ip_generic_getfrag); 1413EXPORT_SYMBOL(ip_queue_xmit); 1414EXPORT_SYMBOL(ip_send_check); 1415