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 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 444 htonl(dst_mtu(&rt->u.dst))); 445 kfree_skb(skb); 446 return -EMSGSIZE; 447 } 448 449 /* 450 * Setup starting values. 451 */ 452 453 hlen = iph->ihl * 4; 454 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 455 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 456 457 /* When frag_list is given, use it. First, check its validity: 458 * some transformers could create wrong frag_list or break existing 459 * one, it is not prohibited. In this case fall back to copying. 460 * 461 * LATER: this step can be merged to real generation of fragments, 462 * we can switch to copy when see the first bad fragment. 463 */ 464 if (skb_shinfo(skb)->frag_list) { 465 struct sk_buff *frag; 466 int first_len = skb_pagelen(skb); 467 468 if (first_len - hlen > mtu || 469 ((first_len - hlen) & 7) || 470 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 471 skb_cloned(skb)) 472 goto slow_path; 473 474 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 475 /* Correct geometry. */ 476 if (frag->len > mtu || 477 ((frag->len & 7) && frag->next) || 478 skb_headroom(frag) < hlen) 479 goto slow_path; 480 481 /* Partially cloned skb? */ 482 if (skb_shared(frag)) 483 goto slow_path; 484 485 BUG_ON(frag->sk); 486 if (skb->sk) { 487 sock_hold(skb->sk); 488 frag->sk = skb->sk; 489 frag->destructor = sock_wfree; 490 skb->truesize -= frag->truesize; 491 } 492 } 493 494 /* Everything is OK. Generate! */ 495 496 err = 0; 497 offset = 0; 498 frag = skb_shinfo(skb)->frag_list; 499 skb_shinfo(skb)->frag_list = NULL; 500 skb->data_len = first_len - skb_headlen(skb); 501 skb->len = first_len; 502 iph->tot_len = htons(first_len); 503 iph->frag_off = htons(IP_MF); 504 ip_send_check(iph); 505 506 for (;;) { 507 /* Prepare header of the next frame, 508 * before previous one went down. */ 509 if (frag) { 510 frag->ip_summed = CHECKSUM_NONE; 511 frag->h.raw = frag->data; 512 frag->nh.raw = __skb_push(frag, hlen); 513 memcpy(frag->nh.raw, iph, hlen); 514 iph = frag->nh.iph; 515 iph->tot_len = htons(frag->len); 516 ip_copy_metadata(frag, skb); 517 if (offset == 0) 518 ip_options_fragment(frag); 519 offset += skb->len - hlen; 520 iph->frag_off = htons(offset>>3); 521 if (frag->next != NULL) 522 iph->frag_off |= htons(IP_MF); 523 /* Ready, complete checksum */ 524 ip_send_check(iph); 525 } 526 527 err = output(skb); 528 529 if (!err) 530 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 531 if (err || !frag) 532 break; 533 534 skb = frag; 535 frag = skb->next; 536 skb->next = NULL; 537 } 538 539 if (err == 0) { 540 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 541 return 0; 542 } 543 544 while (frag) { 545 skb = frag->next; 546 kfree_skb(frag); 547 frag = skb; 548 } 549 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 550 return err; 551 } 552 553 slow_path: 554 left = skb->len - hlen; /* Space per frame */ 555 ptr = raw + hlen; /* Where to start from */ 556 557 #ifdef CONFIG_BRIDGE_NETFILTER 558 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 559 * we need to make room for the encapsulating header */ 560 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb)); 561 mtu -= nf_bridge_pad(skb); 562 #else 563 ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev); 564 #endif 565 /* 566 * Fragment the datagram. 567 */ 568 569 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 570 not_last_frag = iph->frag_off & htons(IP_MF); 571 572 /* 573 * Keep copying data until we run out. 574 */ 575 576 while(left > 0) { 577 len = left; 578 /* IF: it doesn't fit, use 'mtu' - the data space left */ 579 if (len > mtu) 580 len = mtu; 581 /* IF: we are not sending upto and including the packet end 582 then align the next start on an eight byte boundary */ 583 if (len < left) { 584 len &= ~7; 585 } 586 /* 587 * Allocate buffer. 588 */ 589 590 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 591 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 592 err = -ENOMEM; 593 goto fail; 594 } 595 596 /* 597 * Set up data on packet 598 */ 599 600 ip_copy_metadata(skb2, skb); 601 skb_reserve(skb2, ll_rs); 602 skb_put(skb2, len + hlen); 603 skb2->nh.raw = skb2->data; 604 skb2->h.raw = skb2->data + hlen; 605 606 /* 607 * Charge the memory for the fragment to any owner 608 * it might possess 609 */ 610 611 if (skb->sk) 612 skb_set_owner_w(skb2, skb->sk); 613 614 /* 615 * Copy the packet header into the new buffer. 616 */ 617 618 memcpy(skb2->nh.raw, skb->data, hlen); 619 620 /* 621 * Copy a block of the IP datagram. 622 */ 623 if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) 624 BUG(); 625 left -= len; 626 627 /* 628 * Fill in the new header fields. 629 */ 630 iph = skb2->nh.iph; 631 iph->frag_off = htons((offset >> 3)); 632 633 /* ANK: dirty, but effective trick. Upgrade options only if 634 * the segment to be fragmented was THE FIRST (otherwise, 635 * options are already fixed) and make it ONCE 636 * on the initial skb, so that all the following fragments 637 * will inherit fixed options. 638 */ 639 if (offset == 0) 640 ip_options_fragment(skb); 641 642 /* 643 * Added AC : If we are fragmenting a fragment that's not the 644 * last fragment then keep MF on each bit 645 */ 646 if (left > 0 || not_last_frag) 647 iph->frag_off |= htons(IP_MF); 648 ptr += len; 649 offset += len; 650 651 /* 652 * Put this fragment into the sending queue. 653 */ 654 iph->tot_len = htons(len + hlen); 655 656 ip_send_check(iph); 657 658 err = output(skb2); 659 if (err) 660 goto fail; 661 662 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 663 } 664 kfree_skb(skb); 665 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 666 return err; 667 668 fail: 669 kfree_skb(skb); 670 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 671 return err; 672 } 673 674 EXPORT_SYMBOL(ip_fragment); 675 676 int 677 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 678 { 679 struct iovec *iov = from; 680 681 if (skb->ip_summed == CHECKSUM_HW) { 682 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 683 return -EFAULT; 684 } else { 685 unsigned int csum = 0; 686 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 687 return -EFAULT; 688 skb->csum = csum_block_add(skb->csum, csum, odd); 689 } 690 return 0; 691 } 692 693 static inline unsigned int 694 csum_page(struct page *page, int offset, int copy) 695 { 696 char *kaddr; 697 unsigned int csum; 698 kaddr = kmap(page); 699 csum = csum_partial(kaddr + offset, copy, 0); 700 kunmap(page); 701 return csum; 702 } 703 704 static inline int ip_ufo_append_data(struct sock *sk, 705 int getfrag(void *from, char *to, int offset, int len, 706 int odd, struct sk_buff *skb), 707 void *from, int length, int hh_len, int fragheaderlen, 708 int transhdrlen, int mtu,unsigned int flags) 709 { 710 struct sk_buff *skb; 711 int err; 712 713 /* There is support for UDP fragmentation offload by network 714 * device, so create one single skb packet containing complete 715 * udp datagram 716 */ 717 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 718 skb = sock_alloc_send_skb(sk, 719 hh_len + fragheaderlen + transhdrlen + 20, 720 (flags & MSG_DONTWAIT), &err); 721 722 if (skb == NULL) 723 return err; 724 725 /* reserve space for Hardware header */ 726 skb_reserve(skb, hh_len); 727 728 /* create space for UDP/IP header */ 729 skb_put(skb,fragheaderlen + transhdrlen); 730 731 /* initialize network header pointer */ 732 skb->nh.raw = skb->data; 733 734 /* initialize protocol header pointer */ 735 skb->h.raw = skb->data + fragheaderlen; 736 737 skb->ip_summed = CHECKSUM_HW; 738 skb->csum = 0; 739 sk->sk_sndmsg_off = 0; 740 } 741 742 err = skb_append_datato_frags(sk,skb, getfrag, from, 743 (length - transhdrlen)); 744 if (!err) { 745 /* specify the length of each IP datagram fragment*/ 746 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 747 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 748 __skb_queue_tail(&sk->sk_write_queue, skb); 749 750 return 0; 751 } 752 /* There is not enough support do UFO , 753 * so follow normal path 754 */ 755 kfree_skb(skb); 756 return err; 757 } 758 759 /* 760 * ip_append_data() and ip_append_page() can make one large IP datagram 761 * from many pieces of data. Each pieces will be holded on the socket 762 * until ip_push_pending_frames() is called. Each piece can be a page 763 * or non-page data. 764 * 765 * Not only UDP, other transport protocols - e.g. raw sockets - can use 766 * this interface potentially. 767 * 768 * LATER: length must be adjusted by pad at tail, when it is required. 769 */ 770 int ip_append_data(struct sock *sk, 771 int getfrag(void *from, char *to, int offset, int len, 772 int odd, struct sk_buff *skb), 773 void *from, int length, int transhdrlen, 774 struct ipcm_cookie *ipc, struct rtable *rt, 775 unsigned int flags) 776 { 777 struct inet_sock *inet = inet_sk(sk); 778 struct sk_buff *skb; 779 780 struct ip_options *opt = NULL; 781 int hh_len; 782 int exthdrlen; 783 int mtu; 784 int copy; 785 int err; 786 int offset = 0; 787 unsigned int maxfraglen, fragheaderlen; 788 int csummode = CHECKSUM_NONE; 789 790 if (flags&MSG_PROBE) 791 return 0; 792 793 if (skb_queue_empty(&sk->sk_write_queue)) { 794 /* 795 * setup for corking. 796 */ 797 opt = ipc->opt; 798 if (opt) { 799 if (inet->cork.opt == NULL) { 800 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 801 if (unlikely(inet->cork.opt == NULL)) 802 return -ENOBUFS; 803 } 804 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 805 inet->cork.flags |= IPCORK_OPT; 806 inet->cork.addr = ipc->addr; 807 } 808 dst_hold(&rt->u.dst); 809 inet->cork.fragsize = mtu = 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_ALL_CSUM && 844 !exthdrlen) 845 csummode = CHECKSUM_HW; 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; 881 alloc_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->nh.raw = data + exthdrlen; 940 data += fragheaderlen; 941 skb->h.raw = data + exthdrlen; 942 943 if (fraggap) { 944 skb->csum = skb_copy_and_csum_bits( 945 skb_prev, maxfraglen, 946 data + transhdrlen, fraggap, 0); 947 skb_prev->csum = csum_sub(skb_prev->csum, 948 skb->csum); 949 data += fraggap; 950 skb_trim(skb_prev, maxfraglen); 951 } 952 953 copy = datalen - transhdrlen - fraggap; 954 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 955 err = -EFAULT; 956 kfree_skb(skb); 957 goto error; 958 } 959 960 offset += copy; 961 length -= datalen - fraggap; 962 transhdrlen = 0; 963 exthdrlen = 0; 964 csummode = CHECKSUM_NONE; 965 966 /* 967 * Put the packet on the pending queue. 968 */ 969 __skb_queue_tail(&sk->sk_write_queue, skb); 970 continue; 971 } 972 973 if (copy > length) 974 copy = length; 975 976 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 977 unsigned int off; 978 979 off = skb->len; 980 if (getfrag(from, skb_put(skb, copy), 981 offset, copy, off, skb) < 0) { 982 __skb_trim(skb, off); 983 err = -EFAULT; 984 goto error; 985 } 986 } else { 987 int i = skb_shinfo(skb)->nr_frags; 988 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 989 struct page *page = sk->sk_sndmsg_page; 990 int off = sk->sk_sndmsg_off; 991 unsigned int left; 992 993 if (page && (left = PAGE_SIZE - off) > 0) { 994 if (copy >= left) 995 copy = left; 996 if (page != frag->page) { 997 if (i == MAX_SKB_FRAGS) { 998 err = -EMSGSIZE; 999 goto error; 1000 } 1001 get_page(page); 1002 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1003 frag = &skb_shinfo(skb)->frags[i]; 1004 } 1005 } else if (i < MAX_SKB_FRAGS) { 1006 if (copy > PAGE_SIZE) 1007 copy = PAGE_SIZE; 1008 page = alloc_pages(sk->sk_allocation, 0); 1009 if (page == NULL) { 1010 err = -ENOMEM; 1011 goto error; 1012 } 1013 sk->sk_sndmsg_page = page; 1014 sk->sk_sndmsg_off = 0; 1015 1016 skb_fill_page_desc(skb, i, page, 0, 0); 1017 frag = &skb_shinfo(skb)->frags[i]; 1018 skb->truesize += PAGE_SIZE; 1019 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1020 } else { 1021 err = -EMSGSIZE; 1022 goto error; 1023 } 1024 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1025 err = -EFAULT; 1026 goto error; 1027 } 1028 sk->sk_sndmsg_off += copy; 1029 frag->size += copy; 1030 skb->len += copy; 1031 skb->data_len += copy; 1032 } 1033 offset += copy; 1034 length -= copy; 1035 } 1036 1037 return 0; 1038 1039 error: 1040 inet->cork.length -= length; 1041 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1042 return err; 1043 } 1044 1045 ssize_t ip_append_page(struct sock *sk, struct page *page, 1046 int offset, size_t size, int flags) 1047 { 1048 struct inet_sock *inet = inet_sk(sk); 1049 struct sk_buff *skb; 1050 struct rtable *rt; 1051 struct ip_options *opt = NULL; 1052 int hh_len; 1053 int mtu; 1054 int len; 1055 int err; 1056 unsigned int maxfraglen, fragheaderlen, fraggap; 1057 1058 if (inet->hdrincl) 1059 return -EPERM; 1060 1061 if (flags&MSG_PROBE) 1062 return 0; 1063 1064 if (skb_queue_empty(&sk->sk_write_queue)) 1065 return -EINVAL; 1066 1067 rt = inet->cork.rt; 1068 if (inet->cork.flags & IPCORK_OPT) 1069 opt = inet->cork.opt; 1070 1071 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1072 return -EOPNOTSUPP; 1073 1074 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1075 mtu = inet->cork.fragsize; 1076 1077 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1078 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1079 1080 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1081 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1082 return -EMSGSIZE; 1083 } 1084 1085 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1086 return -EINVAL; 1087 1088 inet->cork.length += size; 1089 if ((sk->sk_protocol == IPPROTO_UDP) && 1090 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1091 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1092 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1093 } 1094 1095 1096 while (size > 0) { 1097 int i; 1098 1099 if (skb_is_gso(skb)) 1100 len = size; 1101 else { 1102 1103 /* Check if the remaining data fits into current packet. */ 1104 len = mtu - skb->len; 1105 if (len < size) 1106 len = maxfraglen - skb->len; 1107 } 1108 if (len <= 0) { 1109 struct sk_buff *skb_prev; 1110 char *data; 1111 struct iphdr *iph; 1112 int alloclen; 1113 1114 skb_prev = skb; 1115 fraggap = skb_prev->len - maxfraglen; 1116 1117 alloclen = fragheaderlen + hh_len + fraggap + 15; 1118 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1119 if (unlikely(!skb)) { 1120 err = -ENOBUFS; 1121 goto error; 1122 } 1123 1124 /* 1125 * Fill in the control structures 1126 */ 1127 skb->ip_summed = CHECKSUM_NONE; 1128 skb->csum = 0; 1129 skb_reserve(skb, hh_len); 1130 1131 /* 1132 * Find where to start putting bytes. 1133 */ 1134 data = skb_put(skb, fragheaderlen + fraggap); 1135 skb->nh.iph = iph = (struct iphdr *)data; 1136 data += fragheaderlen; 1137 skb->h.raw = data; 1138 1139 if (fraggap) { 1140 skb->csum = skb_copy_and_csum_bits( 1141 skb_prev, maxfraglen, 1142 data, fraggap, 0); 1143 skb_prev->csum = csum_sub(skb_prev->csum, 1144 skb->csum); 1145 skb_trim(skb_prev, maxfraglen); 1146 } 1147 1148 /* 1149 * Put the packet on the pending queue. 1150 */ 1151 __skb_queue_tail(&sk->sk_write_queue, skb); 1152 continue; 1153 } 1154 1155 i = skb_shinfo(skb)->nr_frags; 1156 if (len > size) 1157 len = size; 1158 if (skb_can_coalesce(skb, i, page, offset)) { 1159 skb_shinfo(skb)->frags[i-1].size += len; 1160 } else if (i < MAX_SKB_FRAGS) { 1161 get_page(page); 1162 skb_fill_page_desc(skb, i, page, offset, len); 1163 } else { 1164 err = -EMSGSIZE; 1165 goto error; 1166 } 1167 1168 if (skb->ip_summed == CHECKSUM_NONE) { 1169 unsigned int csum; 1170 csum = csum_page(page, offset, len); 1171 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1172 } 1173 1174 skb->len += len; 1175 skb->data_len += len; 1176 offset += len; 1177 size -= len; 1178 } 1179 return 0; 1180 1181 error: 1182 inet->cork.length -= size; 1183 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1184 return err; 1185 } 1186 1187 /* 1188 * Combined all pending IP fragments on the socket as one IP datagram 1189 * and push them out. 1190 */ 1191 int ip_push_pending_frames(struct sock *sk) 1192 { 1193 struct sk_buff *skb, *tmp_skb; 1194 struct sk_buff **tail_skb; 1195 struct inet_sock *inet = inet_sk(sk); 1196 struct ip_options *opt = NULL; 1197 struct rtable *rt = inet->cork.rt; 1198 struct iphdr *iph; 1199 __be16 df = 0; 1200 __u8 ttl; 1201 int err = 0; 1202 1203 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1204 goto out; 1205 tail_skb = &(skb_shinfo(skb)->frag_list); 1206 1207 /* move skb->data to ip header from ext header */ 1208 if (skb->data < skb->nh.raw) 1209 __skb_pull(skb, skb->nh.raw - skb->data); 1210 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1211 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1212 *tail_skb = tmp_skb; 1213 tail_skb = &(tmp_skb->next); 1214 skb->len += tmp_skb->len; 1215 skb->data_len += tmp_skb->len; 1216 skb->truesize += tmp_skb->truesize; 1217 __sock_put(tmp_skb->sk); 1218 tmp_skb->destructor = NULL; 1219 tmp_skb->sk = NULL; 1220 } 1221 1222 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1223 * to fragment the frame generated here. No matter, what transforms 1224 * how transforms change size of the packet, it will come out. 1225 */ 1226 if (inet->pmtudisc != IP_PMTUDISC_DO) 1227 skb->local_df = 1; 1228 1229 /* DF bit is set when we want to see DF on outgoing frames. 1230 * If local_df is set too, we still allow to fragment this frame 1231 * locally. */ 1232 if (inet->pmtudisc == IP_PMTUDISC_DO || 1233 (skb->len <= dst_mtu(&rt->u.dst) && 1234 ip_dont_fragment(sk, &rt->u.dst))) 1235 df = htons(IP_DF); 1236 1237 if (inet->cork.flags & IPCORK_OPT) 1238 opt = inet->cork.opt; 1239 1240 if (rt->rt_type == RTN_MULTICAST) 1241 ttl = inet->mc_ttl; 1242 else 1243 ttl = ip_select_ttl(inet, &rt->u.dst); 1244 1245 iph = (struct iphdr *)skb->data; 1246 iph->version = 4; 1247 iph->ihl = 5; 1248 if (opt) { 1249 iph->ihl += opt->optlen>>2; 1250 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1251 } 1252 iph->tos = inet->tos; 1253 iph->tot_len = htons(skb->len); 1254 iph->frag_off = df; 1255 ip_select_ident(iph, &rt->u.dst, sk); 1256 iph->ttl = ttl; 1257 iph->protocol = sk->sk_protocol; 1258 iph->saddr = rt->rt_src; 1259 iph->daddr = rt->rt_dst; 1260 ip_send_check(iph); 1261 1262 skb->priority = sk->sk_priority; 1263 skb->dst = dst_clone(&rt->u.dst); 1264 1265 /* Netfilter gets whole the not fragmented skb. */ 1266 err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, 1267 skb->dst->dev, dst_output); 1268 if (err) { 1269 if (err > 0) 1270 err = inet->recverr ? net_xmit_errno(err) : 0; 1271 if (err) 1272 goto error; 1273 } 1274 1275 out: 1276 inet->cork.flags &= ~IPCORK_OPT; 1277 kfree(inet->cork.opt); 1278 inet->cork.opt = NULL; 1279 if (inet->cork.rt) { 1280 ip_rt_put(inet->cork.rt); 1281 inet->cork.rt = NULL; 1282 } 1283 return err; 1284 1285 error: 1286 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1287 goto out; 1288 } 1289 1290 /* 1291 * Throw away all pending data on the socket. 1292 */ 1293 void ip_flush_pending_frames(struct sock *sk) 1294 { 1295 struct inet_sock *inet = inet_sk(sk); 1296 struct sk_buff *skb; 1297 1298 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1299 kfree_skb(skb); 1300 1301 inet->cork.flags &= ~IPCORK_OPT; 1302 kfree(inet->cork.opt); 1303 inet->cork.opt = NULL; 1304 if (inet->cork.rt) { 1305 ip_rt_put(inet->cork.rt); 1306 inet->cork.rt = NULL; 1307 } 1308 } 1309 1310 1311 /* 1312 * Fetch data from kernel space and fill in checksum if needed. 1313 */ 1314 static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1315 int len, int odd, struct sk_buff *skb) 1316 { 1317 unsigned int csum; 1318 1319 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1320 skb->csum = csum_block_add(skb->csum, csum, odd); 1321 return 0; 1322 } 1323 1324 /* 1325 * Generic function to send a packet as reply to another packet. 1326 * Used to send TCP resets so far. ICMP should use this function too. 1327 * 1328 * Should run single threaded per socket because it uses the sock 1329 * structure to pass arguments. 1330 * 1331 * LATER: switch from ip_build_xmit to ip_append_* 1332 */ 1333 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1334 unsigned int len) 1335 { 1336 struct inet_sock *inet = inet_sk(sk); 1337 struct { 1338 struct ip_options opt; 1339 char data[40]; 1340 } replyopts; 1341 struct ipcm_cookie ipc; 1342 u32 daddr; 1343 struct rtable *rt = (struct rtable*)skb->dst; 1344 1345 if (ip_options_echo(&replyopts.opt, skb)) 1346 return; 1347 1348 daddr = ipc.addr = rt->rt_src; 1349 ipc.opt = NULL; 1350 1351 if (replyopts.opt.optlen) { 1352 ipc.opt = &replyopts.opt; 1353 1354 if (ipc.opt->srr) 1355 daddr = replyopts.opt.faddr; 1356 } 1357 1358 { 1359 struct flowi fl = { .nl_u = { .ip4_u = 1360 { .daddr = daddr, 1361 .saddr = rt->rt_spec_dst, 1362 .tos = RT_TOS(skb->nh.iph->tos) } }, 1363 /* Not quite clean, but right. */ 1364 .uli_u = { .ports = 1365 { .sport = skb->h.th->dest, 1366 .dport = skb->h.th->source } }, 1367 .proto = sk->sk_protocol }; 1368 if (ip_route_output_key(&rt, &fl)) 1369 return; 1370 } 1371 1372 /* And let IP do all the hard work. 1373 1374 This chunk is not reenterable, hence spinlock. 1375 Note that it uses the fact, that this function is called 1376 with locally disabled BH and that sk cannot be already spinlocked. 1377 */ 1378 bh_lock_sock(sk); 1379 inet->tos = skb->nh.iph->tos; 1380 sk->sk_priority = skb->priority; 1381 sk->sk_protocol = skb->nh.iph->protocol; 1382 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1383 &ipc, rt, MSG_DONTWAIT); 1384 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1385 if (arg->csumoffset >= 0) 1386 *((u16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum)); 1387 skb->ip_summed = CHECKSUM_NONE; 1388 ip_push_pending_frames(sk); 1389 } 1390 1391 bh_unlock_sock(sk); 1392 1393 ip_rt_put(rt); 1394 } 1395 1396 void __init ip_init(void) 1397 { 1398 ip_rt_init(); 1399 inet_initpeers(); 1400 1401 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1402 igmp_mc_proc_init(); 1403 #endif 1404 } 1405 1406 EXPORT_SYMBOL(ip_generic_getfrag); 1407 EXPORT_SYMBOL(ip_queue_xmit); 1408 EXPORT_SYMBOL(ip_send_check); 1409