1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * The Internet Protocol (IP) output module. 7 * 8 * Version: $Id: ip_output.c,v 1.100 2002/02/01 22:01:03 davem Exp $ 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Donald Becker, <becker@super.org> 13 * Alan Cox, <Alan.Cox@linux.org> 14 * Richard Underwood 15 * Stefan Becker, <stefanb@yello.ping.de> 16 * Jorge Cwik, <jorge@laser.satlink.net> 17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 18 * Hirokazu Takahashi, <taka@valinux.co.jp> 19 * 20 * See ip_input.c for original log 21 * 22 * Fixes: 23 * Alan Cox : Missing nonblock feature in ip_build_xmit. 24 * Mike Kilburn : htons() missing in ip_build_xmit. 25 * Bradford Johnson: Fix faulty handling of some frames when 26 * no route is found. 27 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit 28 * (in case if packet not accepted by 29 * output firewall rules) 30 * Mike McLagan : Routing by source 31 * Alexey Kuznetsov: use new route cache 32 * Andi Kleen: Fix broken PMTU recovery and remove 33 * some redundant tests. 34 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 35 * Andi Kleen : Replace ip_reply with ip_send_reply. 36 * Andi Kleen : Split fast and slow ip_build_xmit path 37 * for decreased register pressure on x86 38 * and more readibility. 39 * Marc Boucher : When call_out_firewall returns FW_QUEUE, 40 * silently drop skb instead of failing with -EPERM. 41 * Detlev Wengorz : Copy protocol for fragments. 42 * Hirokazu Takahashi: HW checksumming for outgoing UDP 43 * datagrams. 44 * Hirokazu Takahashi: sendfile() on UDP works now. 45 */ 46 47 #include <asm/uaccess.h> 48 #include <asm/system.h> 49 #include <linux/module.h> 50 #include <linux/types.h> 51 #include <linux/kernel.h> 52 #include <linux/sched.h> 53 #include <linux/mm.h> 54 #include <linux/string.h> 55 #include <linux/errno.h> 56 #include <linux/config.h> 57 58 #include <linux/socket.h> 59 #include <linux/sockios.h> 60 #include <linux/in.h> 61 #include <linux/inet.h> 62 #include <linux/netdevice.h> 63 #include <linux/etherdevice.h> 64 #include <linux/proc_fs.h> 65 #include <linux/stat.h> 66 #include <linux/init.h> 67 68 #include <net/snmp.h> 69 #include <net/ip.h> 70 #include <net/protocol.h> 71 #include <net/route.h> 72 #include <net/xfrm.h> 73 #include <linux/skbuff.h> 74 #include <net/sock.h> 75 #include <net/arp.h> 76 #include <net/icmp.h> 77 #include <net/checksum.h> 78 #include <net/inetpeer.h> 79 #include <net/checksum.h> 80 #include <linux/igmp.h> 81 #include <linux/netfilter_ipv4.h> 82 #include <linux/netfilter_bridge.h> 83 #include <linux/mroute.h> 84 #include <linux/netlink.h> 85 #include <linux/tcp.h> 86 87 int sysctl_ip_default_ttl = IPDEFTTL; 88 89 static int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)); 90 91 /* Generate a checksum for an outgoing IP datagram. */ 92 __inline__ void ip_send_check(struct iphdr *iph) 93 { 94 iph->check = 0; 95 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 96 } 97 98 /* dev_loopback_xmit for use with netfilter. */ 99 static int ip_dev_loopback_xmit(struct sk_buff *newskb) 100 { 101 newskb->mac.raw = newskb->data; 102 __skb_pull(newskb, newskb->nh.raw - newskb->data); 103 newskb->pkt_type = PACKET_LOOPBACK; 104 newskb->ip_summed = CHECKSUM_UNNECESSARY; 105 BUG_TRAP(newskb->dst); 106 netif_rx(newskb); 107 return 0; 108 } 109 110 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) 111 { 112 int ttl = inet->uc_ttl; 113 114 if (ttl < 0) 115 ttl = dst_metric(dst, RTAX_HOPLIMIT); 116 return ttl; 117 } 118 119 /* 120 * Add an ip header to a skbuff and send it out. 121 * 122 */ 123 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 124 u32 saddr, u32 daddr, struct ip_options *opt) 125 { 126 struct inet_sock *inet = inet_sk(sk); 127 struct rtable *rt = (struct rtable *)skb->dst; 128 struct iphdr *iph; 129 130 /* Build the IP header. */ 131 if (opt) 132 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); 133 else 134 iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); 135 136 iph->version = 4; 137 iph->ihl = 5; 138 iph->tos = inet->tos; 139 if (ip_dont_fragment(sk, &rt->u.dst)) 140 iph->frag_off = htons(IP_DF); 141 else 142 iph->frag_off = 0; 143 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 144 iph->daddr = rt->rt_dst; 145 iph->saddr = rt->rt_src; 146 iph->protocol = sk->sk_protocol; 147 iph->tot_len = htons(skb->len); 148 ip_select_ident(iph, &rt->u.dst, sk); 149 skb->nh.iph = iph; 150 151 if (opt && opt->optlen) { 152 iph->ihl += opt->optlen>>2; 153 ip_options_build(skb, opt, daddr, rt, 0); 154 } 155 ip_send_check(iph); 156 157 skb->priority = sk->sk_priority; 158 159 /* Send it out. */ 160 return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, 161 dst_output); 162 } 163 164 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); 165 166 static inline int ip_finish_output2(struct sk_buff *skb) 167 { 168 struct dst_entry *dst = skb->dst; 169 struct hh_cache *hh = dst->hh; 170 struct net_device *dev = dst->dev; 171 int hh_len = LL_RESERVED_SPACE(dev); 172 173 /* Be paranoid, rather than too clever. */ 174 if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) { 175 struct sk_buff *skb2; 176 177 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); 178 if (skb2 == NULL) { 179 kfree_skb(skb); 180 return -ENOMEM; 181 } 182 if (skb->sk) 183 skb_set_owner_w(skb2, skb->sk); 184 kfree_skb(skb); 185 skb = skb2; 186 } 187 188 if (hh) { 189 int hh_alen; 190 191 read_lock_bh(&hh->hh_lock); 192 hh_alen = HH_DATA_ALIGN(hh->hh_len); 193 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 194 read_unlock_bh(&hh->hh_lock); 195 skb_push(skb, hh->hh_len); 196 return hh->hh_output(skb); 197 } else if (dst->neighbour) 198 return dst->neighbour->output(skb); 199 200 if (net_ratelimit()) 201 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); 202 kfree_skb(skb); 203 return -EINVAL; 204 } 205 206 static inline int ip_finish_output(struct sk_buff *skb) 207 { 208 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 209 /* Policy lookup after SNAT yielded a new policy */ 210 if (skb->dst->xfrm != NULL) { 211 IPCB(skb)->flags |= IPSKB_REROUTED; 212 return dst_output(skb); 213 } 214 #endif 215 if (skb->len > dst_mtu(skb->dst) && 216 !(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size)) 217 return ip_fragment(skb, ip_finish_output2); 218 else 219 return ip_finish_output2(skb); 220 } 221 222 int ip_mc_output(struct sk_buff *skb) 223 { 224 struct sock *sk = skb->sk; 225 struct rtable *rt = (struct rtable*)skb->dst; 226 struct net_device *dev = rt->u.dst.dev; 227 228 /* 229 * If the indicated interface is up and running, send the packet. 230 */ 231 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 232 233 skb->dev = dev; 234 skb->protocol = htons(ETH_P_IP); 235 236 /* 237 * Multicasts are looped back for other local users 238 */ 239 240 if (rt->rt_flags&RTCF_MULTICAST) { 241 if ((!sk || inet_sk(sk)->mc_loop) 242 #ifdef CONFIG_IP_MROUTE 243 /* Small optimization: do not loopback not local frames, 244 which returned after forwarding; they will be dropped 245 by ip_mr_input in any case. 246 Note, that local frames are looped back to be delivered 247 to local recipients. 248 249 This check is duplicated in ip_mr_input at the moment. 250 */ 251 && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) 252 #endif 253 ) { 254 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 255 if (newskb) 256 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 257 newskb->dev, 258 ip_dev_loopback_xmit); 259 } 260 261 /* Multicasts with ttl 0 must not go beyond the host */ 262 263 if (skb->nh.iph->ttl == 0) { 264 kfree_skb(skb); 265 return 0; 266 } 267 } 268 269 if (rt->rt_flags&RTCF_BROADCAST) { 270 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 271 if (newskb) 272 NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, 273 newskb->dev, ip_dev_loopback_xmit); 274 } 275 276 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev, 277 ip_finish_output, 278 !(IPCB(skb)->flags & IPSKB_REROUTED)); 279 } 280 281 int ip_output(struct sk_buff *skb) 282 { 283 struct net_device *dev = skb->dst->dev; 284 285 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); 286 287 skb->dev = dev; 288 skb->protocol = htons(ETH_P_IP); 289 290 return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, 291 ip_finish_output, 292 !(IPCB(skb)->flags & IPSKB_REROUTED)); 293 } 294 295 int ip_queue_xmit(struct sk_buff *skb, int ipfragok) 296 { 297 struct sock *sk = skb->sk; 298 struct inet_sock *inet = inet_sk(sk); 299 struct ip_options *opt = inet->opt; 300 struct rtable *rt; 301 struct iphdr *iph; 302 303 /* Skip all of this if the packet is already routed, 304 * f.e. by something like SCTP. 305 */ 306 rt = (struct rtable *) skb->dst; 307 if (rt != NULL) 308 goto packet_routed; 309 310 /* Make sure we can route this packet. */ 311 rt = (struct rtable *)__sk_dst_check(sk, 0); 312 if (rt == NULL) { 313 u32 daddr; 314 315 /* Use correct destination address if we have options. */ 316 daddr = inet->daddr; 317 if(opt && opt->srr) 318 daddr = opt->faddr; 319 320 { 321 struct flowi fl = { .oif = sk->sk_bound_dev_if, 322 .nl_u = { .ip4_u = 323 { .daddr = daddr, 324 .saddr = inet->saddr, 325 .tos = RT_CONN_FLAGS(sk) } }, 326 .proto = sk->sk_protocol, 327 .uli_u = { .ports = 328 { .sport = inet->sport, 329 .dport = inet->dport } } }; 330 331 /* If this fails, retransmit mechanism of transport layer will 332 * keep trying until route appears or the connection times 333 * itself out. 334 */ 335 if (ip_route_output_flow(&rt, &fl, sk, 0)) 336 goto no_route; 337 } 338 sk_setup_caps(sk, &rt->u.dst); 339 } 340 skb->dst = dst_clone(&rt->u.dst); 341 342 packet_routed: 343 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) 344 goto no_route; 345 346 /* OK, we know where to send it, allocate and build IP header. */ 347 iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 348 *((__u16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); 349 iph->tot_len = htons(skb->len); 350 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) 351 iph->frag_off = htons(IP_DF); 352 else 353 iph->frag_off = 0; 354 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 355 iph->protocol = sk->sk_protocol; 356 iph->saddr = rt->rt_src; 357 iph->daddr = rt->rt_dst; 358 skb->nh.iph = iph; 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)->tso_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); 376 377 no_route: 378 IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); 379 kfree_skb(skb); 380 return -EHOSTUNREACH; 381 } 382 383 384 static 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; 392 393 /* Copy the flags to each fragment. */ 394 IPCB(to)->flags = IPCB(from)->flags; 395 396 #ifdef CONFIG_NET_SCHED 397 to->tc_index = from->tc_index; 398 #endif 399 #ifdef CONFIG_NETFILTER 400 to->nfmark = from->nfmark; 401 /* Connection association is same as pre-frag packet */ 402 nf_conntrack_put(to->nfct); 403 to->nfct = from->nfct; 404 nf_conntrack_get(to->nfct); 405 to->nfctinfo = from->nfctinfo; 406 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 407 to->ipvs_property = from->ipvs_property; 408 #endif 409 #ifdef CONFIG_BRIDGE_NETFILTER 410 nf_bridge_put(to->nf_bridge); 411 to->nf_bridge = from->nf_bridge; 412 nf_bridge_get(to->nf_bridge); 413 #endif 414 #endif 415 } 416 417 /* 418 * This IP datagram is too large to be sent in one piece. Break it up into 419 * smaller pieces (each of size equal to IP header plus 420 * a block of the data of the original IP data part) that will yet fit in a 421 * single device frame, and queue such a frame for sending. 422 */ 423 424 static int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) 425 { 426 struct iphdr *iph; 427 int raw = 0; 428 int ptr; 429 struct net_device *dev; 430 struct sk_buff *skb2; 431 unsigned int mtu, hlen, left, len, ll_rs; 432 int offset; 433 __be16 not_last_frag; 434 struct rtable *rt = (struct rtable*)skb->dst; 435 int err = 0; 436 437 dev = rt->u.dst.dev; 438 439 /* 440 * Point into the IP datagram header. 441 */ 442 443 iph = skb->nh.iph; 444 445 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { 446 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 447 htonl(dst_mtu(&rt->u.dst))); 448 kfree_skb(skb); 449 return -EMSGSIZE; 450 } 451 452 /* 453 * Setup starting values. 454 */ 455 456 hlen = iph->ihl * 4; 457 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 458 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 459 460 /* When frag_list is given, use it. First, check its validity: 461 * some transformers could create wrong frag_list or break existing 462 * one, it is not prohibited. In this case fall back to copying. 463 * 464 * LATER: this step can be merged to real generation of fragments, 465 * we can switch to copy when see the first bad fragment. 466 */ 467 if (skb_shinfo(skb)->frag_list) { 468 struct sk_buff *frag; 469 int first_len = skb_pagelen(skb); 470 471 if (first_len - hlen > mtu || 472 ((first_len - hlen) & 7) || 473 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 474 skb_cloned(skb)) 475 goto slow_path; 476 477 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 478 /* Correct geometry. */ 479 if (frag->len > mtu || 480 ((frag->len & 7) && frag->next) || 481 skb_headroom(frag) < hlen) 482 goto slow_path; 483 484 /* Partially cloned skb? */ 485 if (skb_shared(frag)) 486 goto slow_path; 487 488 BUG_ON(frag->sk); 489 if (skb->sk) { 490 sock_hold(skb->sk); 491 frag->sk = skb->sk; 492 frag->destructor = sock_wfree; 493 skb->truesize -= frag->truesize; 494 } 495 } 496 497 /* Everything is OK. Generate! */ 498 499 err = 0; 500 offset = 0; 501 frag = skb_shinfo(skb)->frag_list; 502 skb_shinfo(skb)->frag_list = NULL; 503 skb->data_len = first_len - skb_headlen(skb); 504 skb->len = first_len; 505 iph->tot_len = htons(first_len); 506 iph->frag_off = htons(IP_MF); 507 ip_send_check(iph); 508 509 for (;;) { 510 /* Prepare header of the next frame, 511 * before previous one went down. */ 512 if (frag) { 513 frag->ip_summed = CHECKSUM_NONE; 514 frag->h.raw = frag->data; 515 frag->nh.raw = __skb_push(frag, hlen); 516 memcpy(frag->nh.raw, iph, hlen); 517 iph = frag->nh.iph; 518 iph->tot_len = htons(frag->len); 519 ip_copy_metadata(frag, skb); 520 if (offset == 0) 521 ip_options_fragment(frag); 522 offset += skb->len - hlen; 523 iph->frag_off = htons(offset>>3); 524 if (frag->next != NULL) 525 iph->frag_off |= htons(IP_MF); 526 /* Ready, complete checksum */ 527 ip_send_check(iph); 528 } 529 530 err = output(skb); 531 532 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 */ 655 656 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); 657 658 iph->tot_len = htons(len + hlen); 659 660 ip_send_check(iph); 661 662 err = output(skb2); 663 if (err) 664 goto fail; 665 } 666 kfree_skb(skb); 667 IP_INC_STATS(IPSTATS_MIB_FRAGOKS); 668 return err; 669 670 fail: 671 kfree_skb(skb); 672 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); 673 return err; 674 } 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)->ufo_size = (mtu - fragheaderlen); 747 __skb_queue_tail(&sk->sk_write_queue, skb); 748 749 return 0; 750 } 751 /* There is not enough support do UFO , 752 * so follow normal path 753 */ 754 kfree_skb(skb); 755 return err; 756 } 757 758 /* 759 * ip_append_data() and ip_append_page() can make one large IP datagram 760 * from many pieces of data. Each pieces will be holded on the socket 761 * until ip_push_pending_frames() is called. Each piece can be a page 762 * or non-page data. 763 * 764 * Not only UDP, other transport protocols - e.g. raw sockets - can use 765 * this interface potentially. 766 * 767 * LATER: length must be adjusted by pad at tail, when it is required. 768 */ 769 int ip_append_data(struct sock *sk, 770 int getfrag(void *from, char *to, int offset, int len, 771 int odd, struct sk_buff *skb), 772 void *from, int length, int transhdrlen, 773 struct ipcm_cookie *ipc, struct rtable *rt, 774 unsigned int flags) 775 { 776 struct inet_sock *inet = inet_sk(sk); 777 struct sk_buff *skb; 778 779 struct ip_options *opt = NULL; 780 int hh_len; 781 int exthdrlen; 782 int mtu; 783 int copy; 784 int err; 785 int offset = 0; 786 unsigned int maxfraglen, fragheaderlen; 787 int csummode = CHECKSUM_NONE; 788 789 if (flags&MSG_PROBE) 790 return 0; 791 792 if (skb_queue_empty(&sk->sk_write_queue)) { 793 /* 794 * setup for corking. 795 */ 796 opt = ipc->opt; 797 if (opt) { 798 if (inet->cork.opt == NULL) { 799 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 800 if (unlikely(inet->cork.opt == NULL)) 801 return -ENOBUFS; 802 } 803 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 804 inet->cork.flags |= IPCORK_OPT; 805 inet->cork.addr = ipc->addr; 806 } 807 dst_hold(&rt->u.dst); 808 inet->cork.fragsize = mtu = dst_mtu(rt->u.dst.path); 809 inet->cork.rt = rt; 810 inet->cork.length = 0; 811 sk->sk_sndmsg_page = NULL; 812 sk->sk_sndmsg_off = 0; 813 if ((exthdrlen = rt->u.dst.header_len) != 0) { 814 length += exthdrlen; 815 transhdrlen += exthdrlen; 816 } 817 } else { 818 rt = inet->cork.rt; 819 if (inet->cork.flags & IPCORK_OPT) 820 opt = inet->cork.opt; 821 822 transhdrlen = 0; 823 exthdrlen = 0; 824 mtu = inet->cork.fragsize; 825 } 826 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 827 828 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 829 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 830 831 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 832 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 833 return -EMSGSIZE; 834 } 835 836 /* 837 * transhdrlen > 0 means that this is the first fragment and we wish 838 * it won't be fragmented in the future. 839 */ 840 if (transhdrlen && 841 length + fragheaderlen <= mtu && 842 rt->u.dst.dev->features&(NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM) && 843 !exthdrlen) 844 csummode = CHECKSUM_HW; 845 846 inet->cork.length += length; 847 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && 848 (rt->u.dst.dev->features & NETIF_F_UFO)) { 849 850 if(ip_ufo_append_data(sk, getfrag, from, length, hh_len, 851 fragheaderlen, transhdrlen, mtu, flags)) 852 goto error; 853 854 return 0; 855 } 856 857 /* So, what's going on in the loop below? 858 * 859 * We use calculated fragment length to generate chained skb, 860 * each of segments is IP fragment ready for sending to network after 861 * adding appropriate IP header. 862 */ 863 864 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 865 goto alloc_new_skb; 866 867 while (length > 0) { 868 /* Check if the remaining data fits into current packet. */ 869 copy = mtu - skb->len; 870 if (copy < length) 871 copy = maxfraglen - skb->len; 872 if (copy <= 0) { 873 char *data; 874 unsigned int datalen; 875 unsigned int fraglen; 876 unsigned int fraggap; 877 unsigned int alloclen; 878 struct sk_buff *skb_prev; 879 alloc_new_skb: 880 skb_prev = skb; 881 if (skb_prev) 882 fraggap = skb_prev->len - maxfraglen; 883 else 884 fraggap = 0; 885 886 /* 887 * If remaining data exceeds the mtu, 888 * we know we need more fragment(s). 889 */ 890 datalen = length + fraggap; 891 if (datalen > mtu - fragheaderlen) 892 datalen = maxfraglen - fragheaderlen; 893 fraglen = datalen + fragheaderlen; 894 895 if ((flags & MSG_MORE) && 896 !(rt->u.dst.dev->features&NETIF_F_SG)) 897 alloclen = mtu; 898 else 899 alloclen = datalen + fragheaderlen; 900 901 /* The last fragment gets additional space at tail. 902 * Note, with MSG_MORE we overallocate on fragments, 903 * because we have no idea what fragment will be 904 * the last. 905 */ 906 if (datalen == length) 907 alloclen += rt->u.dst.trailer_len; 908 909 if (transhdrlen) { 910 skb = sock_alloc_send_skb(sk, 911 alloclen + hh_len + 15, 912 (flags & MSG_DONTWAIT), &err); 913 } else { 914 skb = NULL; 915 if (atomic_read(&sk->sk_wmem_alloc) <= 916 2 * sk->sk_sndbuf) 917 skb = sock_wmalloc(sk, 918 alloclen + hh_len + 15, 1, 919 sk->sk_allocation); 920 if (unlikely(skb == NULL)) 921 err = -ENOBUFS; 922 } 923 if (skb == NULL) 924 goto error; 925 926 /* 927 * Fill in the control structures 928 */ 929 skb->ip_summed = csummode; 930 skb->csum = 0; 931 skb_reserve(skb, hh_len); 932 933 /* 934 * Find where to start putting bytes. 935 */ 936 data = skb_put(skb, fraglen); 937 skb->nh.raw = data + exthdrlen; 938 data += fragheaderlen; 939 skb->h.raw = data + exthdrlen; 940 941 if (fraggap) { 942 skb->csum = skb_copy_and_csum_bits( 943 skb_prev, maxfraglen, 944 data + transhdrlen, fraggap, 0); 945 skb_prev->csum = csum_sub(skb_prev->csum, 946 skb->csum); 947 data += fraggap; 948 skb_trim(skb_prev, maxfraglen); 949 } 950 951 copy = datalen - transhdrlen - fraggap; 952 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 953 err = -EFAULT; 954 kfree_skb(skb); 955 goto error; 956 } 957 958 offset += copy; 959 length -= datalen - fraggap; 960 transhdrlen = 0; 961 exthdrlen = 0; 962 csummode = CHECKSUM_NONE; 963 964 /* 965 * Put the packet on the pending queue. 966 */ 967 __skb_queue_tail(&sk->sk_write_queue, skb); 968 continue; 969 } 970 971 if (copy > length) 972 copy = length; 973 974 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 975 unsigned int off; 976 977 off = skb->len; 978 if (getfrag(from, skb_put(skb, copy), 979 offset, copy, off, skb) < 0) { 980 __skb_trim(skb, off); 981 err = -EFAULT; 982 goto error; 983 } 984 } else { 985 int i = skb_shinfo(skb)->nr_frags; 986 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 987 struct page *page = sk->sk_sndmsg_page; 988 int off = sk->sk_sndmsg_off; 989 unsigned int left; 990 991 if (page && (left = PAGE_SIZE - off) > 0) { 992 if (copy >= left) 993 copy = left; 994 if (page != frag->page) { 995 if (i == MAX_SKB_FRAGS) { 996 err = -EMSGSIZE; 997 goto error; 998 } 999 get_page(page); 1000 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1001 frag = &skb_shinfo(skb)->frags[i]; 1002 } 1003 } else if (i < MAX_SKB_FRAGS) { 1004 if (copy > PAGE_SIZE) 1005 copy = PAGE_SIZE; 1006 page = alloc_pages(sk->sk_allocation, 0); 1007 if (page == NULL) { 1008 err = -ENOMEM; 1009 goto error; 1010 } 1011 sk->sk_sndmsg_page = page; 1012 sk->sk_sndmsg_off = 0; 1013 1014 skb_fill_page_desc(skb, i, page, 0, 0); 1015 frag = &skb_shinfo(skb)->frags[i]; 1016 skb->truesize += PAGE_SIZE; 1017 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1018 } else { 1019 err = -EMSGSIZE; 1020 goto error; 1021 } 1022 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1023 err = -EFAULT; 1024 goto error; 1025 } 1026 sk->sk_sndmsg_off += copy; 1027 frag->size += copy; 1028 skb->len += copy; 1029 skb->data_len += copy; 1030 } 1031 offset += copy; 1032 length -= copy; 1033 } 1034 1035 return 0; 1036 1037 error: 1038 inet->cork.length -= length; 1039 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1040 return err; 1041 } 1042 1043 ssize_t ip_append_page(struct sock *sk, struct page *page, 1044 int offset, size_t size, int flags) 1045 { 1046 struct inet_sock *inet = inet_sk(sk); 1047 struct sk_buff *skb; 1048 struct rtable *rt; 1049 struct ip_options *opt = NULL; 1050 int hh_len; 1051 int mtu; 1052 int len; 1053 int err; 1054 unsigned int maxfraglen, fragheaderlen, fraggap; 1055 1056 if (inet->hdrincl) 1057 return -EPERM; 1058 1059 if (flags&MSG_PROBE) 1060 return 0; 1061 1062 if (skb_queue_empty(&sk->sk_write_queue)) 1063 return -EINVAL; 1064 1065 rt = inet->cork.rt; 1066 if (inet->cork.flags & IPCORK_OPT) 1067 opt = inet->cork.opt; 1068 1069 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1070 return -EOPNOTSUPP; 1071 1072 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1073 mtu = inet->cork.fragsize; 1074 1075 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1076 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1077 1078 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1079 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1080 return -EMSGSIZE; 1081 } 1082 1083 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1084 return -EINVAL; 1085 1086 inet->cork.length += size; 1087 if ((sk->sk_protocol == IPPROTO_UDP) && 1088 (rt->u.dst.dev->features & NETIF_F_UFO)) 1089 skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen); 1090 1091 1092 while (size > 0) { 1093 int i; 1094 1095 if (skb_shinfo(skb)->ufo_size) 1096 len = size; 1097 else { 1098 1099 /* Check if the remaining data fits into current packet. */ 1100 len = mtu - skb->len; 1101 if (len < size) 1102 len = maxfraglen - skb->len; 1103 } 1104 if (len <= 0) { 1105 struct sk_buff *skb_prev; 1106 char *data; 1107 struct iphdr *iph; 1108 int alloclen; 1109 1110 skb_prev = skb; 1111 fraggap = skb_prev->len - maxfraglen; 1112 1113 alloclen = fragheaderlen + hh_len + fraggap + 15; 1114 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1115 if (unlikely(!skb)) { 1116 err = -ENOBUFS; 1117 goto error; 1118 } 1119 1120 /* 1121 * Fill in the control structures 1122 */ 1123 skb->ip_summed = CHECKSUM_NONE; 1124 skb->csum = 0; 1125 skb_reserve(skb, hh_len); 1126 1127 /* 1128 * Find where to start putting bytes. 1129 */ 1130 data = skb_put(skb, fragheaderlen + fraggap); 1131 skb->nh.iph = iph = (struct iphdr *)data; 1132 data += fragheaderlen; 1133 skb->h.raw = data; 1134 1135 if (fraggap) { 1136 skb->csum = skb_copy_and_csum_bits( 1137 skb_prev, maxfraglen, 1138 data, fraggap, 0); 1139 skb_prev->csum = csum_sub(skb_prev->csum, 1140 skb->csum); 1141 skb_trim(skb_prev, maxfraglen); 1142 } 1143 1144 /* 1145 * Put the packet on the pending queue. 1146 */ 1147 __skb_queue_tail(&sk->sk_write_queue, skb); 1148 continue; 1149 } 1150 1151 i = skb_shinfo(skb)->nr_frags; 1152 if (len > size) 1153 len = size; 1154 if (skb_can_coalesce(skb, i, page, offset)) { 1155 skb_shinfo(skb)->frags[i-1].size += len; 1156 } else if (i < MAX_SKB_FRAGS) { 1157 get_page(page); 1158 skb_fill_page_desc(skb, i, page, offset, len); 1159 } else { 1160 err = -EMSGSIZE; 1161 goto error; 1162 } 1163 1164 if (skb->ip_summed == CHECKSUM_NONE) { 1165 unsigned int csum; 1166 csum = csum_page(page, offset, len); 1167 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1168 } 1169 1170 skb->len += len; 1171 skb->data_len += len; 1172 offset += len; 1173 size -= len; 1174 } 1175 return 0; 1176 1177 error: 1178 inet->cork.length -= size; 1179 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); 1180 return err; 1181 } 1182 1183 /* 1184 * Combined all pending IP fragments on the socket as one IP datagram 1185 * and push them out. 1186 */ 1187 int ip_push_pending_frames(struct sock *sk) 1188 { 1189 struct sk_buff *skb, *tmp_skb; 1190 struct sk_buff **tail_skb; 1191 struct inet_sock *inet = inet_sk(sk); 1192 struct ip_options *opt = NULL; 1193 struct rtable *rt = inet->cork.rt; 1194 struct iphdr *iph; 1195 __be16 df = 0; 1196 __u8 ttl; 1197 int err = 0; 1198 1199 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1200 goto out; 1201 tail_skb = &(skb_shinfo(skb)->frag_list); 1202 1203 /* move skb->data to ip header from ext header */ 1204 if (skb->data < skb->nh.raw) 1205 __skb_pull(skb, skb->nh.raw - skb->data); 1206 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1207 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); 1208 *tail_skb = tmp_skb; 1209 tail_skb = &(tmp_skb->next); 1210 skb->len += tmp_skb->len; 1211 skb->data_len += tmp_skb->len; 1212 skb->truesize += tmp_skb->truesize; 1213 __sock_put(tmp_skb->sk); 1214 tmp_skb->destructor = NULL; 1215 tmp_skb->sk = NULL; 1216 } 1217 1218 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1219 * to fragment the frame generated here. No matter, what transforms 1220 * how transforms change size of the packet, it will come out. 1221 */ 1222 if (inet->pmtudisc != IP_PMTUDISC_DO) 1223 skb->local_df = 1; 1224 1225 /* DF bit is set when we want to see DF on outgoing frames. 1226 * If local_df is set too, we still allow to fragment this frame 1227 * locally. */ 1228 if (inet->pmtudisc == IP_PMTUDISC_DO || 1229 (skb->len <= dst_mtu(&rt->u.dst) && 1230 ip_dont_fragment(sk, &rt->u.dst))) 1231 df = htons(IP_DF); 1232 1233 if (inet->cork.flags & IPCORK_OPT) 1234 opt = inet->cork.opt; 1235 1236 if (rt->rt_type == RTN_MULTICAST) 1237 ttl = inet->mc_ttl; 1238 else 1239 ttl = ip_select_ttl(inet, &rt->u.dst); 1240 1241 iph = (struct iphdr *)skb->data; 1242 iph->version = 4; 1243 iph->ihl = 5; 1244 if (opt) { 1245 iph->ihl += opt->optlen>>2; 1246 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1247 } 1248 iph->tos = inet->tos; 1249 iph->tot_len = htons(skb->len); 1250 iph->frag_off = df; 1251 if (!df) { 1252 __ip_select_ident(iph, &rt->u.dst, 0); 1253 } else { 1254 iph->id = htons(inet->id++); 1255 } 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