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 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 <net/checksum.h> 79 #include <linux/igmp.h> 80 #include <linux/netfilter_ipv4.h> 81 #include <linux/netfilter_bridge.h> 82 #include <linux/mroute.h> 83 #include <linux/netlink.h> 84 #include <linux/tcp.h> 85 86 int sysctl_ip_default_ttl = IPDEFTTL; 87 88 /* Generate a checksum for an outgoing IP datagram. */ 89 __inline__ void ip_send_check(struct iphdr *iph) 90 { 91 iph->check = 0; 92 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 93 } 94 95 /* dev_loopback_xmit for use with netfilter. */ 96 static int ip_dev_loopback_xmit(struct sk_buff *newskb) 97 { 98 newskb->mac.raw = newskb->data; 99 __skb_pull(newskb, newskb->nh.raw - newskb->data); 100 newskb->pkt_type = PACKET_LOOPBACK; 101 newskb->ip_summed = CHECKSUM_UNNECESSARY; 102 BUG_TRAP(newskb->dst); 103 netif_rx(newskb); 104 return 0; 105 } 106 107 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) 108 { 109 int ttl = inet->uc_ttl; 110 111 if (ttl < 0) 112 ttl = dst_metric(dst, RTAX_HOPLIMIT); 113 return ttl; 114 } 115 116 /* 117 * Add an ip header to a skbuff and send it out. 118 * 119 */ 120 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 121 u32 saddr, u32 daddr, struct ip_options *opt) 122 { 123 struct inet_sock *inet = inet_sk(sk); 124 struct rtable *rt = (struct rtable *)skb->dst; 125 struct iphdr *iph; 126 127 /* Build the IP header. */ 128 if (opt) 129 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); 130 else 131 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); 132 133 iph->version = 4; 134 iph->ihl = 5; 135 iph->tos = inet->tos; 136 if (ip_dont_fragment(sk, &rt->u.dst)) 137 iph->frag_off = htons(IP_DF); 138 else 139 iph->frag_off = 0; 140 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 141 iph->daddr = rt->rt_dst; 142 iph->saddr = rt->rt_src; 143 iph->protocol = sk->sk_protocol; 144 iph->tot_len = htons(skb->len); 145 ip_select_ident(iph, &rt->u.dst, sk); 146 skb->nh.iph = iph; 147 148 if (opt && opt->optlen) { 149 iph->ihl += opt->optlen>>2; 150 ip_options_build(skb, opt, daddr, rt, 0); 151 } 152 ip_send_check(iph); 153 154 skb->priority = sk->sk_priority; 155 156 /* Send it out. */ 157 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 158 dst_output); 159 } 160 161 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); 162 163 static inline int ip_finish_output2(struct sk_buff *skb) 164 { 165 struct dst_entry *dst = skb->dst; 166 struct hh_cache *hh = dst->hh; 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 (hh) { 186 int hh_alen; 187 188 read_lock_bh(&hh->hh_lock); 189 hh_alen = HH_DATA_ALIGN(hh->hh_len); 190 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 191 read_unlock_bh(&hh->hh_lock); 192 skb_push(skb, hh->hh_len); 193 return hh->hh_output(skb); 194 } else if (dst->neighbour) 195 return dst->neighbour->output(skb); 196 197 if (net_ratelimit()) 198 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); 199 kfree_skb(skb); 200 return -EINVAL; 201 } 202 203 static inline int ip_finish_output(struct sk_buff *skb) 204 { 205 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 206 /* Policy lookup after SNAT yielded a new policy */ 207 if (skb->dst->xfrm != NULL) { 208 IPCB(skb)->flags |= IPSKB_REROUTED; 209 return dst_output(skb); 210 } 211 #endif 212 if (skb->len > dst_mtu(skb->dst) && !skb_is_gso(skb)) 213 return ip_fragment(skb, ip_finish_output2); 214 else 215 return ip_finish_output2(skb); 216 } 217 218 int ip_mc_output(struct sk_buff *skb) 219 { 220 struct sock *sk = skb->sk; 221 struct rtable *rt = (struct rtable*)skb->dst; 222 struct net_device *dev = rt->u.dst.dev; 223 224 /* 225 * If the indicated interface is up and running, send the packet. 226 */ 227 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 228 229 skb->dev = dev; 230 skb->protocol = htons(ETH_P_IP); 231 232 /* 233 * Multicasts are looped back for other local users 234 */ 235 236 if (rt->rt_flags&RTCF_MULTICAST) { 237 if ((!sk || inet_sk(sk)->mc_loop) 238 #ifdef CONFIG_IP_MROUTE 239 /* Small optimization: do not loopback not local frames, 240 which returned after forwarding; they will be dropped 241 by ip_mr_input in any case. 242 Note, that local frames are looped back to be delivered 243 to local recipients. 244 245 This check is duplicated in ip_mr_input at the moment. 246 */ 247 && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) 248 #endif 249 ) { 250 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 251 if (newskb) 252 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 253 newskb->dev, 254 ip_dev_loopback_xmit); 255 } 256 257 /* Multicasts with ttl 0 must not go beyond the host */ 258 259 if (skb->nh.iph->ttl == 0) { 260 kfree_skb(skb); 261 return 0; 262 } 263 } 264 265 if (rt->rt_flags&RTCF_BROADCAST) { 266 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 267 if (newskb) 268 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 269 newskb->dev, ip_dev_loopback_xmit); 270 } 271 272 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev, 273 ip_finish_output, 274 !(IPCB(skb)->flags & IPSKB_REROUTED)); 275 } 276 277 int ip_output(struct sk_buff *skb) 278 { 279 struct net_device *dev = skb->dst->dev; 280 281 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 282 283 skb->dev = dev; 284 skb->protocol = htons(ETH_P_IP); 285 286 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, 287 ip_finish_output, 288 !(IPCB(skb)->flags & IPSKB_REROUTED)); 289 } 290 291 int ip_queue_xmit(struct sk_buff *skb, int ipfragok) 292 { 293 struct sock *sk = skb->sk; 294 struct inet_sock *inet = inet_sk(sk); 295 struct ip_options *opt = inet->opt; 296 struct rtable *rt; 297 struct iphdr *iph; 298 299 /* Skip all of this if the packet is already routed, 300 * f.e. by something like SCTP. 301 */ 302 rt = (struct rtable *) skb->dst; 303 if (rt != NULL) 304 goto packet_routed; 305 306 /* Make sure we can route this packet. */ 307 rt = (struct rtable *)__sk_dst_check(sk, 0); 308 if (rt == NULL) { 309 u32 daddr; 310 311 /* Use correct destination address if we have options. */ 312 daddr = inet->daddr; 313 if(opt && opt->srr) 314 daddr = opt->faddr; 315 316 { 317 struct flowi fl = { .oif = sk->sk_bound_dev_if, 318 .nl_u = { .ip4_u = 319 { .daddr = daddr, 320 .saddr = inet->saddr, 321 .tos = RT_CONN_FLAGS(sk) } }, 322 .proto = sk->sk_protocol, 323 .uli_u = { .ports = 324 { .sport = inet->sport, 325 .dport = inet->dport } } }; 326 327 /* If this fails, retransmit mechanism of transport layer will 328 * keep trying until route appears or the connection times 329 * itself out. 330 */ 331 if (ip_route_output_flow(&rt, &fl, sk, 0)) 332 goto no_route; 333 } 334 sk_setup_caps(sk, &rt->u.dst); 335 } 336 skb->dst = dst_clone(&rt->u.dst); 337 338 packet_routed: 339 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) 340 goto no_route; 341 342 /* OK, we know where to send it, allocate and build IP header. */ 343 iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 344 *((__u16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); 345 iph->tot_len = htons(skb->len); 346 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) 347 iph->frag_off = htons(IP_DF); 348 else 349 iph->frag_off = 0; 350 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 351 iph->protocol = sk->sk_protocol; 352 iph->saddr = rt->rt_src; 353 iph->daddr = rt->rt_dst; 354 skb->nh.iph = iph; 355 /* Transport layer set skb->h.foo itself. */ 356 357 if (opt && opt->optlen) { 358 iph->ihl += opt->optlen >> 2; 359 ip_options_build(skb, opt, inet->daddr, rt, 0); 360 } 361 362 ip_select_ident_more(iph, &rt->u.dst, sk, 363 (skb_shinfo(skb)->gso_segs ?: 1) - 1); 364 365 /* Add an IP checksum. */ 366 ip_send_check(iph); 367 368 skb->priority = sk->sk_priority; 369 370 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 371 dst_output); 372 373 no_route: 374 IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); 375 kfree_skb(skb); 376 return -EHOSTUNREACH; 377 } 378 379 380 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) 381 { 382 to->pkt_type = from->pkt_type; 383 to->priority = from->priority; 384 to->protocol = from->protocol; 385 dst_release(to->dst); 386 to->dst = dst_clone(from->dst); 387 to->dev = from->dev; 388 389 /* Copy the flags to each fragment. */ 390 IPCB(to)->flags = IPCB(from)->flags; 391 392 #ifdef CONFIG_NET_SCHED 393 to->tc_index = from->tc_index; 394 #endif 395 #ifdef CONFIG_NETFILTER 396 to->nfmark = from->nfmark; 397 /* Connection association is same as pre-frag packet */ 398 nf_conntrack_put(to->nfct); 399 to->nfct = from->nfct; 400 nf_conntrack_get(to->nfct); 401 to->nfctinfo = from->nfctinfo; 402 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 403 to->ipvs_property = from->ipvs_property; 404 #endif 405 #ifdef CONFIG_BRIDGE_NETFILTER 406 nf_bridge_put(to->nf_bridge); 407 to->nf_bridge = from->nf_bridge; 408 nf_bridge_get(to->nf_bridge); 409 #endif 410 #endif 411 skb_copy_secmark(to, from); 412 } 413 414 /* 415 * This IP datagram is too large to be sent in one piece. Break it up into 416 * smaller pieces (each of size equal to IP header plus 417 * a block of the data of the original IP data part) that will yet fit in a 418 * single device frame, and queue such a frame for sending. 419 */ 420 421 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) 422 { 423 struct iphdr *iph; 424 int raw = 0; 425 int ptr; 426 struct net_device *dev; 427 struct sk_buff *skb2; 428 unsigned int mtu, hlen, left, len, ll_rs; 429 int offset; 430 __be16 not_last_frag; 431 struct rtable *rt = (struct rtable*)skb->dst; 432 int err = 0; 433 434 dev = rt->u.dst.dev; 435 436 /* 437 * Point into the IP datagram header. 438 */ 439 440 iph = skb->nh.iph; 441 442 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { 443 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 444 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 445 htonl(dst_mtu(&rt->u.dst))); 446 kfree_skb(skb); 447 return -EMSGSIZE; 448 } 449 450 /* 451 * Setup starting values. 452 */ 453 454 hlen = iph->ihl * 4; 455 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 456 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 457 458 /* When frag_list is given, use it. First, check its validity: 459 * some transformers could create wrong frag_list or break existing 460 * one, it is not prohibited. In this case fall back to copying. 461 * 462 * LATER: this step can be merged to real generation of fragments, 463 * we can switch to copy when see the first bad fragment. 464 */ 465 if (skb_shinfo(skb)->frag_list) { 466 struct sk_buff *frag; 467 int first_len = skb_pagelen(skb); 468 469 if (first_len - hlen > mtu || 470 ((first_len - hlen) & 7) || 471 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 472 skb_cloned(skb)) 473 goto slow_path; 474 475 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 476 /* Correct geometry. */ 477 if (frag->len > mtu || 478 ((frag->len & 7) && frag->next) || 479 skb_headroom(frag) < hlen) 480 goto slow_path; 481 482 /* Partially cloned skb? */ 483 if (skb_shared(frag)) 484 goto slow_path; 485 486 BUG_ON(frag->sk); 487 if (skb->sk) { 488 sock_hold(skb->sk); 489 frag->sk = skb->sk; 490 frag->destructor = sock_wfree; 491 skb->truesize -= frag->truesize; 492 } 493 } 494 495 /* Everything is OK. Generate! */ 496 497 err = 0; 498 offset = 0; 499 frag = skb_shinfo(skb)->frag_list; 500 skb_shinfo(skb)->frag_list = NULL; 501 skb->data_len = first_len - skb_headlen(skb); 502 skb->len = first_len; 503 iph->tot_len = htons(first_len); 504 iph->frag_off = htons(IP_MF); 505 ip_send_check(iph); 506 507 for (;;) { 508 /* Prepare header of the next frame, 509 * before previous one went down. */ 510 if (frag) { 511 frag->ip_summed = CHECKSUM_NONE; 512 frag->h.raw = frag->data; 513 frag->nh.raw = __skb_push(frag, hlen); 514 memcpy(frag->nh.raw, iph, hlen); 515 iph = frag->nh.iph; 516 iph->tot_len = htons(frag->len); 517 ip_copy_metadata(frag, skb); 518 if (offset == 0) 519 ip_options_fragment(frag); 520 offset += skb->len - hlen; 521 iph->frag_off = htons(offset>>3); 522 if (frag->next != NULL) 523 iph->frag_off |= htons(IP_MF); 524 /* Ready, complete checksum */ 525 ip_send_check(iph); 526 } 527 528 err = output(skb); 529 530 if (!err) 531 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 532 if (err || !frag) 533 break; 534 535 skb = frag; 536 frag = skb->next; 537 skb->next = NULL; 538 } 539 540 if (err == 0) { 541 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 542 return 0; 543 } 544 545 while (frag) { 546 skb = frag->next; 547 kfree_skb(frag); 548 frag = skb; 549 } 550 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 551 return err; 552 } 553 554 slow_path: 555 left = skb->len - hlen; /* Space per frame */ 556 ptr = raw + hlen; /* Where to start from */ 557 558 #ifdef CONFIG_BRIDGE_NETFILTER 559 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 560 * we need to make room for the encapsulating header */ 561 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb)); 562 mtu -= nf_bridge_pad(skb); 563 #else 564 ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev); 565 #endif 566 /* 567 * Fragment the datagram. 568 */ 569 570 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 571 not_last_frag = iph->frag_off & htons(IP_MF); 572 573 /* 574 * Keep copying data until we run out. 575 */ 576 577 while(left > 0) { 578 len = left; 579 /* IF: it doesn't fit, use 'mtu' - the data space left */ 580 if (len > mtu) 581 len = mtu; 582 /* IF: we are not sending upto and including the packet end 583 then align the next start on an eight byte boundary */ 584 if (len < left) { 585 len &= ~7; 586 } 587 /* 588 * Allocate buffer. 589 */ 590 591 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 592 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 593 err = -ENOMEM; 594 goto fail; 595 } 596 597 /* 598 * Set up data on packet 599 */ 600 601 ip_copy_metadata(skb2, skb); 602 skb_reserve(skb2, ll_rs); 603 skb_put(skb2, len + hlen); 604 skb2->nh.raw = skb2->data; 605 skb2->h.raw = skb2->data + hlen; 606 607 /* 608 * Charge the memory for the fragment to any owner 609 * it might possess 610 */ 611 612 if (skb->sk) 613 skb_set_owner_w(skb2, skb->sk); 614 615 /* 616 * Copy the packet header into the new buffer. 617 */ 618 619 memcpy(skb2->nh.raw, skb->data, hlen); 620 621 /* 622 * Copy a block of the IP datagram. 623 */ 624 if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) 625 BUG(); 626 left -= len; 627 628 /* 629 * Fill in the new header fields. 630 */ 631 iph = skb2->nh.iph; 632 iph->frag_off = htons((offset >> 3)); 633 634 /* ANK: dirty, but effective trick. Upgrade options only if 635 * the segment to be fragmented was THE FIRST (otherwise, 636 * options are already fixed) and make it ONCE 637 * on the initial skb, so that all the following fragments 638 * will inherit fixed options. 639 */ 640 if (offset == 0) 641 ip_options_fragment(skb); 642 643 /* 644 * Added AC : If we are fragmenting a fragment that's not the 645 * last fragment then keep MF on each bit 646 */ 647 if (left > 0 || not_last_frag) 648 iph->frag_off |= htons(IP_MF); 649 ptr += len; 650 offset += len; 651 652 /* 653 * Put this fragment into the sending queue. 654 */ 655 iph->tot_len = htons(len + hlen); 656 657 ip_send_check(iph); 658 659 err = output(skb2); 660 if (err) 661 goto fail; 662 663 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 664 } 665 kfree_skb(skb); 666 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 667 return err; 668 669 fail: 670 kfree_skb(skb); 671 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 672 return err; 673 } 674 675 EXPORT_SYMBOL(ip_fragment); 676 677 int 678 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 679 { 680 struct iovec *iov = from; 681 682 if (skb->ip_summed == CHECKSUM_HW) { 683 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 684 return -EFAULT; 685 } else { 686 unsigned int csum = 0; 687 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 688 return -EFAULT; 689 skb->csum = csum_block_add(skb->csum, csum, odd); 690 } 691 return 0; 692 } 693 694 static inline unsigned int 695 csum_page(struct page *page, int offset, int copy) 696 { 697 char *kaddr; 698 unsigned int csum; 699 kaddr = kmap(page); 700 csum = csum_partial(kaddr + offset, copy, 0); 701 kunmap(page); 702 return csum; 703 } 704 705 static inline int ip_ufo_append_data(struct sock *sk, 706 int getfrag(void *from, char *to, int offset, int len, 707 int odd, struct sk_buff *skb), 708 void *from, int length, int hh_len, int fragheaderlen, 709 int transhdrlen, int mtu,unsigned int flags) 710 { 711 struct sk_buff *skb; 712 int err; 713 714 /* There is support for UDP fragmentation offload by network 715 * device, so create one single skb packet containing complete 716 * udp datagram 717 */ 718 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 719 skb = sock_alloc_send_skb(sk, 720 hh_len + fragheaderlen + transhdrlen + 20, 721 (flags & MSG_DONTWAIT), &err); 722 723 if (skb == NULL) 724 return err; 725 726 /* reserve space for Hardware header */ 727 skb_reserve(skb, hh_len); 728 729 /* create space for UDP/IP header */ 730 skb_put(skb,fragheaderlen + transhdrlen); 731 732 /* initialize network header pointer */ 733 skb->nh.raw = skb->data; 734 735 /* initialize protocol header pointer */ 736 skb->h.raw = skb->data + fragheaderlen; 737 738 skb->ip_summed = CHECKSUM_HW; 739 skb->csum = 0; 740 sk->sk_sndmsg_off = 0; 741 } 742 743 err = skb_append_datato_frags(sk,skb, getfrag, from, 744 (length - transhdrlen)); 745 if (!err) { 746 /* specify the length of each IP datagram fragment*/ 747 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 748 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 749 __skb_queue_tail(&sk->sk_write_queue, skb); 750 751 return 0; 752 } 753 /* There is not enough support do UFO , 754 * so follow normal path 755 */ 756 kfree_skb(skb); 757 return err; 758 } 759 760 /* 761 * ip_append_data() and ip_append_page() can make one large IP datagram 762 * from many pieces of data. Each pieces will be holded on the socket 763 * until ip_push_pending_frames() is called. Each piece can be a page 764 * or non-page data. 765 * 766 * Not only UDP, other transport protocols - e.g. raw sockets - can use 767 * this interface potentially. 768 * 769 * LATER: length must be adjusted by pad at tail, when it is required. 770 */ 771 int ip_append_data(struct sock *sk, 772 int getfrag(void *from, char *to, int offset, int len, 773 int odd, struct sk_buff *skb), 774 void *from, int length, int transhdrlen, 775 struct ipcm_cookie *ipc, struct rtable *rt, 776 unsigned int flags) 777 { 778 struct inet_sock *inet = inet_sk(sk); 779 struct sk_buff *skb; 780 781 struct ip_options *opt = NULL; 782 int hh_len; 783 int exthdrlen; 784 int mtu; 785 int copy; 786 int err; 787 int offset = 0; 788 unsigned int maxfraglen, fragheaderlen; 789 int csummode = CHECKSUM_NONE; 790 791 if (flags&MSG_PROBE) 792 return 0; 793 794 if (skb_queue_empty(&sk->sk_write_queue)) { 795 /* 796 * setup for corking. 797 */ 798 opt = ipc->opt; 799 if (opt) { 800 if (inet->cork.opt == NULL) { 801 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 802 if (unlikely(inet->cork.opt == NULL)) 803 return -ENOBUFS; 804 } 805 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 806 inet->cork.flags |= IPCORK_OPT; 807 inet->cork.addr = ipc->addr; 808 } 809 dst_hold(&rt->u.dst); 810 inet->cork.fragsize = mtu = dst_mtu(rt->u.dst.path); 811 inet->cork.rt = rt; 812 inet->cork.length = 0; 813 sk->sk_sndmsg_page = NULL; 814 sk->sk_sndmsg_off = 0; 815 if ((exthdrlen = rt->u.dst.header_len) != 0) { 816 length += exthdrlen; 817 transhdrlen += exthdrlen; 818 } 819 } else { 820 rt = inet->cork.rt; 821 if (inet->cork.flags & IPCORK_OPT) 822 opt = inet->cork.opt; 823 824 transhdrlen = 0; 825 exthdrlen = 0; 826 mtu = inet->cork.fragsize; 827 } 828 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 829 830 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 831 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 832 833 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 834 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 835 return -EMSGSIZE; 836 } 837 838 /* 839 * transhdrlen > 0 means that this is the first fragment and we wish 840 * it won't be fragmented in the future. 841 */ 842 if (transhdrlen && 843 length + fragheaderlen <= mtu && 844 rt->u.dst.dev->features & NETIF_F_ALL_CSUM && 845 !exthdrlen) 846 csummode = CHECKSUM_HW; 847 848 inet->cork.length += length; 849 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 850 (rt->u.dst.dev->features & NETIF_F_UFO)) { 851 852 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 853 fragheaderlen, transhdrlen, mtu, 854 flags); 855 if (err) 856 goto error; 857 return 0; 858 } 859 860 /* So, what's going on in the loop below? 861 * 862 * We use calculated fragment length to generate chained skb, 863 * each of segments is IP fragment ready for sending to network after 864 * adding appropriate IP header. 865 */ 866 867 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 868 goto alloc_new_skb; 869 870 while (length > 0) { 871 /* Check if the remaining data fits into current packet. */ 872 copy = mtu - skb->len; 873 if (copy < length) 874 copy = maxfraglen - skb->len; 875 if (copy <= 0) { 876 char *data; 877 unsigned int datalen; 878 unsigned int fraglen; 879 unsigned int fraggap; 880 unsigned int alloclen; 881 struct sk_buff *skb_prev; 882 alloc_new_skb: 883 skb_prev = skb; 884 if (skb_prev) 885 fraggap = skb_prev->len - maxfraglen; 886 else 887 fraggap = 0; 888 889 /* 890 * If remaining data exceeds the mtu, 891 * we know we need more fragment(s). 892 */ 893 datalen = length + fraggap; 894 if (datalen > mtu - fragheaderlen) 895 datalen = maxfraglen - fragheaderlen; 896 fraglen = datalen + fragheaderlen; 897 898 if ((flags & MSG_MORE) && 899 !(rt->u.dst.dev->features&NETIF_F_SG)) 900 alloclen = mtu; 901 else 902 alloclen = datalen + fragheaderlen; 903 904 /* The last fragment gets additional space at tail. 905 * Note, with MSG_MORE we overallocate on fragments, 906 * because we have no idea what fragment will be 907 * the last. 908 */ 909 if (datalen == length + fraggap) 910 alloclen += rt->u.dst.trailer_len; 911 912 if (transhdrlen) { 913 skb = sock_alloc_send_skb(sk, 914 alloclen + hh_len + 15, 915 (flags & MSG_DONTWAIT), &err); 916 } else { 917 skb = NULL; 918 if (atomic_read(&sk->sk_wmem_alloc) <= 919 2 * sk->sk_sndbuf) 920 skb = sock_wmalloc(sk, 921 alloclen + hh_len + 15, 1, 922 sk->sk_allocation); 923 if (unlikely(skb == NULL)) 924 err = -ENOBUFS; 925 } 926 if (skb == NULL) 927 goto error; 928 929 /* 930 * Fill in the control structures 931 */ 932 skb->ip_summed = csummode; 933 skb->csum = 0; 934 skb_reserve(skb, hh_len); 935 936 /* 937 * Find where to start putting bytes. 938 */ 939 data = skb_put(skb, fraglen); 940 skb->nh.raw = data + exthdrlen; 941 data += fragheaderlen; 942 skb->h.raw = data + exthdrlen; 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 1040 error: 1041 inet->cork.length -= length; 1042 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1043 return err; 1044 } 1045 1046 ssize_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 char *data; 1112 struct iphdr *iph; 1113 int alloclen; 1114 1115 skb_prev = skb; 1116 fraggap = skb_prev->len - maxfraglen; 1117 1118 alloclen = fragheaderlen + hh_len + fraggap + 15; 1119 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1120 if (unlikely(!skb)) { 1121 err = -ENOBUFS; 1122 goto error; 1123 } 1124 1125 /* 1126 * Fill in the control structures 1127 */ 1128 skb->ip_summed = CHECKSUM_NONE; 1129 skb->csum = 0; 1130 skb_reserve(skb, hh_len); 1131 1132 /* 1133 * Find where to start putting bytes. 1134 */ 1135 data = skb_put(skb, fragheaderlen + fraggap); 1136 skb->nh.iph = iph = (struct iphdr *)data; 1137 data += fragheaderlen; 1138 skb->h.raw = data; 1139 1140 if (fraggap) { 1141 skb->csum = skb_copy_and_csum_bits( 1142 skb_prev, maxfraglen, 1143 data, fraggap, 0); 1144 skb_prev->csum = csum_sub(skb_prev->csum, 1145 skb->csum); 1146 pskb_trim_unique(skb_prev, maxfraglen); 1147 } 1148 1149 /* 1150 * Put the packet on the pending queue. 1151 */ 1152 __skb_queue_tail(&sk->sk_write_queue, skb); 1153 continue; 1154 } 1155 1156 i = skb_shinfo(skb)->nr_frags; 1157 if (len > size) 1158 len = size; 1159 if (skb_can_coalesce(skb, i, page, offset)) { 1160 skb_shinfo(skb)->frags[i-1].size += len; 1161 } else if (i < MAX_SKB_FRAGS) { 1162 get_page(page); 1163 skb_fill_page_desc(skb, i, page, offset, len); 1164 } else { 1165 err = -EMSGSIZE; 1166 goto error; 1167 } 1168 1169 if (skb->ip_summed == CHECKSUM_NONE) { 1170 unsigned int csum; 1171 csum = csum_page(page, offset, len); 1172 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1173 } 1174 1175 skb->len += len; 1176 skb->data_len += len; 1177 offset += len; 1178 size -= len; 1179 } 1180 return 0; 1181 1182 error: 1183 inet->cork.length -= size; 1184 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1185 return err; 1186 } 1187 1188 /* 1189 * Combined all pending IP fragments on the socket as one IP datagram 1190 * and push them out. 1191 */ 1192 int ip_push_pending_frames(struct sock *sk) 1193 { 1194 struct sk_buff *skb, *tmp_skb; 1195 struct sk_buff **tail_skb; 1196 struct inet_sock *inet = inet_sk(sk); 1197 struct ip_options *opt = NULL; 1198 struct rtable *rt = inet->cork.rt; 1199 struct iphdr *iph; 1200 __be16 df = 0; 1201 __u8 ttl; 1202 int err = 0; 1203 1204 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1205 goto out; 1206 tail_skb = &(skb_shinfo(skb)->frag_list); 1207 1208 /* move skb->data to ip header from ext header */ 1209 if (skb->data < skb->nh.raw) 1210 __skb_pull(skb, skb->nh.raw - skb->data); 1211 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1212 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1213 *tail_skb = tmp_skb; 1214 tail_skb = &(tmp_skb->next); 1215 skb->len += tmp_skb->len; 1216 skb->data_len += tmp_skb->len; 1217 skb->truesize += tmp_skb->truesize; 1218 __sock_put(tmp_skb->sk); 1219 tmp_skb->destructor = NULL; 1220 tmp_skb->sk = NULL; 1221 } 1222 1223 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1224 * to fragment the frame generated here. No matter, what transforms 1225 * how transforms change size of the packet, it will come out. 1226 */ 1227 if (inet->pmtudisc != IP_PMTUDISC_DO) 1228 skb->local_df = 1; 1229 1230 /* DF bit is set when we want to see DF on outgoing frames. 1231 * If local_df is set too, we still allow to fragment this frame 1232 * locally. */ 1233 if (inet->pmtudisc == IP_PMTUDISC_DO || 1234 (skb->len <= dst_mtu(&rt->u.dst) && 1235 ip_dont_fragment(sk, &rt->u.dst))) 1236 df = htons(IP_DF); 1237 1238 if (inet->cork.flags & IPCORK_OPT) 1239 opt = inet->cork.opt; 1240 1241 if (rt->rt_type == RTN_MULTICAST) 1242 ttl = inet->mc_ttl; 1243 else 1244 ttl = ip_select_ttl(inet, &rt->u.dst); 1245 1246 iph = (struct iphdr *)skb->data; 1247 iph->version = 4; 1248 iph->ihl = 5; 1249 if (opt) { 1250 iph->ihl += opt->optlen>>2; 1251 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1252 } 1253 iph->tos = inet->tos; 1254 iph->tot_len = htons(skb->len); 1255 iph->frag_off = df; 1256 ip_select_ident(iph, &rt->u.dst, sk); 1257 iph->ttl = ttl; 1258 iph->protocol = sk->sk_protocol; 1259 iph->saddr = rt->rt_src; 1260 iph->daddr = rt->rt_dst; 1261 ip_send_check(iph); 1262 1263 skb->priority = sk->sk_priority; 1264 skb->dst = dst_clone(&rt->u.dst); 1265 1266 /* Netfilter gets whole the not fragmented skb. */ 1267 err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, 1268 skb->dst->dev, dst_output); 1269 if (err) { 1270 if (err > 0) 1271 err = inet->recverr ? net_xmit_errno(err) : 0; 1272 if (err) 1273 goto error; 1274 } 1275 1276 out: 1277 inet->cork.flags &= ~IPCORK_OPT; 1278 kfree(inet->cork.opt); 1279 inet->cork.opt = NULL; 1280 if (inet->cork.rt) { 1281 ip_rt_put(inet->cork.rt); 1282 inet->cork.rt = NULL; 1283 } 1284 return err; 1285 1286 error: 1287 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1288 goto out; 1289 } 1290 1291 /* 1292 * Throw away all pending data on the socket. 1293 */ 1294 void ip_flush_pending_frames(struct sock *sk) 1295 { 1296 struct inet_sock *inet = inet_sk(sk); 1297 struct sk_buff *skb; 1298 1299 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1300 kfree_skb(skb); 1301 1302 inet->cork.flags &= ~IPCORK_OPT; 1303 kfree(inet->cork.opt); 1304 inet->cork.opt = NULL; 1305 if (inet->cork.rt) { 1306 ip_rt_put(inet->cork.rt); 1307 inet->cork.rt = NULL; 1308 } 1309 } 1310 1311 1312 /* 1313 * Fetch data from kernel space and fill in checksum if needed. 1314 */ 1315 static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1316 int len, int odd, struct sk_buff *skb) 1317 { 1318 unsigned int 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 */ 1334 void 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 u32 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 = { .nl_u = { .ip4_u = 1361 { .daddr = daddr, 1362 .saddr = rt->rt_spec_dst, 1363 .tos = RT_TOS(skb->nh.iph->tos) } }, 1364 /* Not quite clean, but right. */ 1365 .uli_u = { .ports = 1366 { .sport = skb->h.th->dest, 1367 .dport = skb->h.th->source } }, 1368 .proto = sk->sk_protocol }; 1369 if (ip_route_output_key(&rt, &fl)) 1370 return; 1371 } 1372 1373 /* And let IP do all the hard work. 1374 1375 This chunk is not reenterable, hence spinlock. 1376 Note that it uses the fact, that this function is called 1377 with locally disabled BH and that sk cannot be already spinlocked. 1378 */ 1379 bh_lock_sock(sk); 1380 inet->tos = skb->nh.iph->tos; 1381 sk->sk_priority = skb->priority; 1382 sk->sk_protocol = skb->nh.iph->protocol; 1383 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1384 &ipc, rt, MSG_DONTWAIT); 1385 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1386 if (arg->csumoffset >= 0) 1387 *((u16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum)); 1388 skb->ip_summed = CHECKSUM_NONE; 1389 ip_push_pending_frames(sk); 1390 } 1391 1392 bh_unlock_sock(sk); 1393 1394 ip_rt_put(rt); 1395 } 1396 1397 void __init ip_init(void) 1398 { 1399 ip_rt_init(); 1400 inet_initpeers(); 1401 1402 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1403 igmp_mc_proc_init(); 1404 #endif 1405 } 1406 1407 EXPORT_SYMBOL(ip_generic_getfrag); 1408 EXPORT_SYMBOL(ip_queue_xmit); 1409 EXPORT_SYMBOL(ip_send_check); 1410