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 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Donald Becker, <becker@super.org> 11 * Alan Cox, <Alan.Cox@linux.org> 12 * Richard Underwood 13 * Stefan Becker, <stefanb@yello.ping.de> 14 * Jorge Cwik, <jorge@laser.satlink.net> 15 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 16 * Hirokazu Takahashi, <taka@valinux.co.jp> 17 * 18 * See ip_input.c for original log 19 * 20 * Fixes: 21 * Alan Cox : Missing nonblock feature in ip_build_xmit. 22 * Mike Kilburn : htons() missing in ip_build_xmit. 23 * Bradford Johnson: Fix faulty handling of some frames when 24 * no route is found. 25 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit 26 * (in case if packet not accepted by 27 * output firewall rules) 28 * Mike McLagan : Routing by source 29 * Alexey Kuznetsov: use new route cache 30 * Andi Kleen: Fix broken PMTU recovery and remove 31 * some redundant tests. 32 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 33 * Andi Kleen : Replace ip_reply with ip_send_reply. 34 * Andi Kleen : Split fast and slow ip_build_xmit path 35 * for decreased register pressure on x86 36 * and more readibility. 37 * Marc Boucher : When call_out_firewall returns FW_QUEUE, 38 * silently drop skb instead of failing with -EPERM. 39 * Detlev Wengorz : Copy protocol for fragments. 40 * Hirokazu Takahashi: HW checksumming for outgoing UDP 41 * datagrams. 42 * Hirokazu Takahashi: sendfile() on UDP works now. 43 */ 44 45 #include <asm/uaccess.h> 46 #include <asm/system.h> 47 #include <linux/module.h> 48 #include <linux/types.h> 49 #include <linux/kernel.h> 50 #include <linux/mm.h> 51 #include <linux/string.h> 52 #include <linux/errno.h> 53 #include <linux/highmem.h> 54 55 #include <linux/socket.h> 56 #include <linux/sockios.h> 57 #include <linux/in.h> 58 #include <linux/inet.h> 59 #include <linux/netdevice.h> 60 #include <linux/etherdevice.h> 61 #include <linux/proc_fs.h> 62 #include <linux/stat.h> 63 #include <linux/init.h> 64 65 #include <net/snmp.h> 66 #include <net/ip.h> 67 #include <net/protocol.h> 68 #include <net/route.h> 69 #include <net/xfrm.h> 70 #include <linux/skbuff.h> 71 #include <net/sock.h> 72 #include <net/arp.h> 73 #include <net/icmp.h> 74 #include <net/checksum.h> 75 #include <net/inetpeer.h> 76 #include <linux/igmp.h> 77 #include <linux/netfilter_ipv4.h> 78 #include <linux/netfilter_bridge.h> 79 #include <linux/mroute.h> 80 #include <linux/netlink.h> 81 #include <linux/tcp.h> 82 83 int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; 84 85 /* Generate a checksum for an outgoing IP datagram. */ 86 __inline__ void ip_send_check(struct iphdr *iph) 87 { 88 iph->check = 0; 89 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 90 } 91 92 int __ip_local_out(struct sk_buff *skb) 93 { 94 struct iphdr *iph = ip_hdr(skb); 95 96 iph->tot_len = htons(skb->len); 97 ip_send_check(iph); 98 return nf_hook(PF_INET, NF_INET_LOCAL_OUT, skb, NULL, skb->dst->dev, 99 dst_output); 100 } 101 102 int ip_local_out(struct sk_buff *skb) 103 { 104 int err; 105 106 err = __ip_local_out(skb); 107 if (likely(err == 1)) 108 err = dst_output(skb); 109 110 return err; 111 } 112 EXPORT_SYMBOL_GPL(ip_local_out); 113 114 /* dev_loopback_xmit for use with netfilter. */ 115 static int ip_dev_loopback_xmit(struct sk_buff *newskb) 116 { 117 skb_reset_mac_header(newskb); 118 __skb_pull(newskb, skb_network_offset(newskb)); 119 newskb->pkt_type = PACKET_LOOPBACK; 120 newskb->ip_summed = CHECKSUM_UNNECESSARY; 121 WARN_ON(!newskb->dst); 122 netif_rx(newskb); 123 return 0; 124 } 125 126 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) 127 { 128 int ttl = inet->uc_ttl; 129 130 if (ttl < 0) 131 ttl = dst_metric(dst, RTAX_HOPLIMIT); 132 return ttl; 133 } 134 135 /* 136 * Add an ip header to a skbuff and send it out. 137 * 138 */ 139 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 140 __be32 saddr, __be32 daddr, struct ip_options *opt) 141 { 142 struct inet_sock *inet = inet_sk(sk); 143 struct rtable *rt = skb->rtable; 144 struct iphdr *iph; 145 146 /* Build the IP header. */ 147 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 148 skb_reset_network_header(skb); 149 iph = ip_hdr(skb); 150 iph->version = 4; 151 iph->ihl = 5; 152 iph->tos = inet->tos; 153 if (ip_dont_fragment(sk, &rt->u.dst)) 154 iph->frag_off = htons(IP_DF); 155 else 156 iph->frag_off = 0; 157 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 158 iph->daddr = rt->rt_dst; 159 iph->saddr = rt->rt_src; 160 iph->protocol = sk->sk_protocol; 161 ip_select_ident(iph, &rt->u.dst, sk); 162 163 if (opt && opt->optlen) { 164 iph->ihl += opt->optlen>>2; 165 ip_options_build(skb, opt, daddr, rt, 0); 166 } 167 168 skb->priority = sk->sk_priority; 169 skb->mark = sk->sk_mark; 170 171 /* Send it out. */ 172 return ip_local_out(skb); 173 } 174 175 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); 176 177 static inline int ip_finish_output2(struct sk_buff *skb) 178 { 179 struct dst_entry *dst = skb->dst; 180 struct rtable *rt = (struct rtable *)dst; 181 struct net_device *dev = dst->dev; 182 unsigned int hh_len = LL_RESERVED_SPACE(dev); 183 184 if (rt->rt_type == RTN_MULTICAST) 185 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTMCASTPKTS); 186 else if (rt->rt_type == RTN_BROADCAST) 187 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTBCASTPKTS); 188 189 /* Be paranoid, rather than too clever. */ 190 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { 191 struct sk_buff *skb2; 192 193 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); 194 if (skb2 == NULL) { 195 kfree_skb(skb); 196 return -ENOMEM; 197 } 198 if (skb->sk) 199 skb_set_owner_w(skb2, skb->sk); 200 kfree_skb(skb); 201 skb = skb2; 202 } 203 204 if (dst->hh) 205 return neigh_hh_output(dst->hh, skb); 206 else if (dst->neighbour) 207 return dst->neighbour->output(skb); 208 209 if (net_ratelimit()) 210 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); 211 kfree_skb(skb); 212 return -EINVAL; 213 } 214 215 static inline int ip_skb_dst_mtu(struct sk_buff *skb) 216 { 217 struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL; 218 219 return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ? 220 skb->dst->dev->mtu : dst_mtu(skb->dst); 221 } 222 223 static int ip_finish_output(struct sk_buff *skb) 224 { 225 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) 226 /* Policy lookup after SNAT yielded a new policy */ 227 if (skb->dst->xfrm != NULL) { 228 IPCB(skb)->flags |= IPSKB_REROUTED; 229 return dst_output(skb); 230 } 231 #endif 232 if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb)) 233 return ip_fragment(skb, ip_finish_output2); 234 else 235 return ip_finish_output2(skb); 236 } 237 238 int ip_mc_output(struct sk_buff *skb) 239 { 240 struct sock *sk = skb->sk; 241 struct rtable *rt = skb->rtable; 242 struct net_device *dev = rt->u.dst.dev; 243 244 /* 245 * If the indicated interface is up and running, send the packet. 246 */ 247 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTREQUESTS); 248 249 skb->dev = dev; 250 skb->protocol = htons(ETH_P_IP); 251 252 /* 253 * Multicasts are looped back for other local users 254 */ 255 256 if (rt->rt_flags&RTCF_MULTICAST) { 257 if ((!sk || inet_sk(sk)->mc_loop) 258 #ifdef CONFIG_IP_MROUTE 259 /* Small optimization: do not loopback not local frames, 260 which returned after forwarding; they will be dropped 261 by ip_mr_input in any case. 262 Note, that local frames are looped back to be delivered 263 to local recipients. 264 265 This check is duplicated in ip_mr_input at the moment. 266 */ 267 && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) 268 #endif 269 ) { 270 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 271 if (newskb) 272 NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb, 273 NULL, newskb->dev, 274 ip_dev_loopback_xmit); 275 } 276 277 /* Multicasts with ttl 0 must not go beyond the host */ 278 279 if (ip_hdr(skb)->ttl == 0) { 280 kfree_skb(skb); 281 return 0; 282 } 283 } 284 285 if (rt->rt_flags&RTCF_BROADCAST) { 286 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 287 if (newskb) 288 NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb, NULL, 289 newskb->dev, ip_dev_loopback_xmit); 290 } 291 292 return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, skb->dev, 293 ip_finish_output, 294 !(IPCB(skb)->flags & IPSKB_REROUTED)); 295 } 296 297 int ip_output(struct sk_buff *skb) 298 { 299 struct net_device *dev = skb->dst->dev; 300 301 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTREQUESTS); 302 303 skb->dev = dev; 304 skb->protocol = htons(ETH_P_IP); 305 306 return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, dev, 307 ip_finish_output, 308 !(IPCB(skb)->flags & IPSKB_REROUTED)); 309 } 310 311 int ip_queue_xmit(struct sk_buff *skb, int ipfragok) 312 { 313 struct sock *sk = skb->sk; 314 struct inet_sock *inet = inet_sk(sk); 315 struct ip_options *opt = inet->opt; 316 struct rtable *rt; 317 struct iphdr *iph; 318 319 /* Skip all of this if the packet is already routed, 320 * f.e. by something like SCTP. 321 */ 322 rt = skb->rtable; 323 if (rt != NULL) 324 goto packet_routed; 325 326 /* Make sure we can route this packet. */ 327 rt = (struct rtable *)__sk_dst_check(sk, 0); 328 if (rt == NULL) { 329 __be32 daddr; 330 331 /* Use correct destination address if we have options. */ 332 daddr = inet->daddr; 333 if(opt && opt->srr) 334 daddr = opt->faddr; 335 336 { 337 struct flowi fl = { .oif = sk->sk_bound_dev_if, 338 .nl_u = { .ip4_u = 339 { .daddr = daddr, 340 .saddr = inet->saddr, 341 .tos = RT_CONN_FLAGS(sk) } }, 342 .proto = sk->sk_protocol, 343 .flags = inet_sk_flowi_flags(sk), 344 .uli_u = { .ports = 345 { .sport = inet->sport, 346 .dport = inet->dport } } }; 347 348 /* If this fails, retransmit mechanism of transport layer will 349 * keep trying until route appears or the connection times 350 * itself out. 351 */ 352 security_sk_classify_flow(sk, &fl); 353 if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0)) 354 goto no_route; 355 } 356 sk_setup_caps(sk, &rt->u.dst); 357 } 358 skb->dst = dst_clone(&rt->u.dst); 359 360 packet_routed: 361 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) 362 goto no_route; 363 364 /* OK, we know where to send it, allocate and build IP header. */ 365 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); 366 skb_reset_network_header(skb); 367 iph = ip_hdr(skb); 368 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); 369 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) 370 iph->frag_off = htons(IP_DF); 371 else 372 iph->frag_off = 0; 373 iph->ttl = ip_select_ttl(inet, &rt->u.dst); 374 iph->protocol = sk->sk_protocol; 375 iph->saddr = rt->rt_src; 376 iph->daddr = rt->rt_dst; 377 /* Transport layer set skb->h.foo itself. */ 378 379 if (opt && opt->optlen) { 380 iph->ihl += opt->optlen >> 2; 381 ip_options_build(skb, opt, inet->daddr, rt, 0); 382 } 383 384 ip_select_ident_more(iph, &rt->u.dst, sk, 385 (skb_shinfo(skb)->gso_segs ?: 1) - 1); 386 387 skb->priority = sk->sk_priority; 388 skb->mark = sk->sk_mark; 389 390 return ip_local_out(skb); 391 392 no_route: 393 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 394 kfree_skb(skb); 395 return -EHOSTUNREACH; 396 } 397 398 399 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) 400 { 401 to->pkt_type = from->pkt_type; 402 to->priority = from->priority; 403 to->protocol = from->protocol; 404 dst_release(to->dst); 405 to->dst = dst_clone(from->dst); 406 to->dev = from->dev; 407 to->mark = from->mark; 408 409 /* Copy the flags to each fragment. */ 410 IPCB(to)->flags = IPCB(from)->flags; 411 412 #ifdef CONFIG_NET_SCHED 413 to->tc_index = from->tc_index; 414 #endif 415 nf_copy(to, from); 416 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ 417 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) 418 to->nf_trace = from->nf_trace; 419 #endif 420 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 421 to->ipvs_property = from->ipvs_property; 422 #endif 423 skb_copy_secmark(to, from); 424 } 425 426 /* 427 * This IP datagram is too large to be sent in one piece. Break it up into 428 * smaller pieces (each of size equal to IP header plus 429 * a block of the data of the original IP data part) that will yet fit in a 430 * single device frame, and queue such a frame for sending. 431 */ 432 433 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) 434 { 435 struct iphdr *iph; 436 int raw = 0; 437 int ptr; 438 struct net_device *dev; 439 struct sk_buff *skb2; 440 unsigned int mtu, hlen, left, len, ll_rs, pad; 441 int offset; 442 __be16 not_last_frag; 443 struct rtable *rt = skb->rtable; 444 int err = 0; 445 446 dev = rt->u.dst.dev; 447 448 /* 449 * Point into the IP datagram header. 450 */ 451 452 iph = ip_hdr(skb); 453 454 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { 455 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); 456 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 457 htonl(ip_skb_dst_mtu(skb))); 458 kfree_skb(skb); 459 return -EMSGSIZE; 460 } 461 462 /* 463 * Setup starting values. 464 */ 465 466 hlen = iph->ihl * 4; 467 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ 468 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; 469 470 /* When frag_list is given, use it. First, check its validity: 471 * some transformers could create wrong frag_list or break existing 472 * one, it is not prohibited. In this case fall back to copying. 473 * 474 * LATER: this step can be merged to real generation of fragments, 475 * we can switch to copy when see the first bad fragment. 476 */ 477 if (skb_shinfo(skb)->frag_list) { 478 struct sk_buff *frag; 479 int first_len = skb_pagelen(skb); 480 int truesizes = 0; 481 482 if (first_len - hlen > mtu || 483 ((first_len - hlen) & 7) || 484 (iph->frag_off & htons(IP_MF|IP_OFFSET)) || 485 skb_cloned(skb)) 486 goto slow_path; 487 488 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { 489 /* Correct geometry. */ 490 if (frag->len > mtu || 491 ((frag->len & 7) && frag->next) || 492 skb_headroom(frag) < hlen) 493 goto slow_path; 494 495 /* Partially cloned skb? */ 496 if (skb_shared(frag)) 497 goto slow_path; 498 499 BUG_ON(frag->sk); 500 if (skb->sk) { 501 sock_hold(skb->sk); 502 frag->sk = skb->sk; 503 frag->destructor = sock_wfree; 504 truesizes += frag->truesize; 505 } 506 } 507 508 /* Everything is OK. Generate! */ 509 510 err = 0; 511 offset = 0; 512 frag = skb_shinfo(skb)->frag_list; 513 skb_shinfo(skb)->frag_list = NULL; 514 skb->data_len = first_len - skb_headlen(skb); 515 skb->truesize -= truesizes; 516 skb->len = first_len; 517 iph->tot_len = htons(first_len); 518 iph->frag_off = htons(IP_MF); 519 ip_send_check(iph); 520 521 for (;;) { 522 /* Prepare header of the next frame, 523 * before previous one went down. */ 524 if (frag) { 525 frag->ip_summed = CHECKSUM_NONE; 526 skb_reset_transport_header(frag); 527 __skb_push(frag, hlen); 528 skb_reset_network_header(frag); 529 memcpy(skb_network_header(frag), iph, hlen); 530 iph = ip_hdr(frag); 531 iph->tot_len = htons(frag->len); 532 ip_copy_metadata(frag, skb); 533 if (offset == 0) 534 ip_options_fragment(frag); 535 offset += skb->len - hlen; 536 iph->frag_off = htons(offset>>3); 537 if (frag->next != NULL) 538 iph->frag_off |= htons(IP_MF); 539 /* Ready, complete checksum */ 540 ip_send_check(iph); 541 } 542 543 err = output(skb); 544 545 if (!err) 546 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); 547 if (err || !frag) 548 break; 549 550 skb = frag; 551 frag = skb->next; 552 skb->next = NULL; 553 } 554 555 if (err == 0) { 556 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); 557 return 0; 558 } 559 560 while (frag) { 561 skb = frag->next; 562 kfree_skb(frag); 563 frag = skb; 564 } 565 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); 566 return err; 567 } 568 569 slow_path: 570 left = skb->len - hlen; /* Space per frame */ 571 ptr = raw + hlen; /* Where to start from */ 572 573 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 574 * we need to make room for the encapsulating header 575 */ 576 pad = nf_bridge_pad(skb); 577 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad); 578 mtu -= pad; 579 580 /* 581 * Fragment the datagram. 582 */ 583 584 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 585 not_last_frag = iph->frag_off & htons(IP_MF); 586 587 /* 588 * Keep copying data until we run out. 589 */ 590 591 while (left > 0) { 592 len = left; 593 /* IF: it doesn't fit, use 'mtu' - the data space left */ 594 if (len > mtu) 595 len = mtu; 596 /* IF: we are not sending upto and including the packet end 597 then align the next start on an eight byte boundary */ 598 if (len < left) { 599 len &= ~7; 600 } 601 /* 602 * Allocate buffer. 603 */ 604 605 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 606 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 607 err = -ENOMEM; 608 goto fail; 609 } 610 611 /* 612 * Set up data on packet 613 */ 614 615 ip_copy_metadata(skb2, skb); 616 skb_reserve(skb2, ll_rs); 617 skb_put(skb2, len + hlen); 618 skb_reset_network_header(skb2); 619 skb2->transport_header = skb2->network_header + hlen; 620 621 /* 622 * Charge the memory for the fragment to any owner 623 * it might possess 624 */ 625 626 if (skb->sk) 627 skb_set_owner_w(skb2, skb->sk); 628 629 /* 630 * Copy the packet header into the new buffer. 631 */ 632 633 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); 634 635 /* 636 * Copy a block of the IP datagram. 637 */ 638 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) 639 BUG(); 640 left -= len; 641 642 /* 643 * Fill in the new header fields. 644 */ 645 iph = ip_hdr(skb2); 646 iph->frag_off = htons((offset >> 3)); 647 648 /* ANK: dirty, but effective trick. Upgrade options only if 649 * the segment to be fragmented was THE FIRST (otherwise, 650 * options are already fixed) and make it ONCE 651 * on the initial skb, so that all the following fragments 652 * will inherit fixed options. 653 */ 654 if (offset == 0) 655 ip_options_fragment(skb); 656 657 /* 658 * Added AC : If we are fragmenting a fragment that's not the 659 * last fragment then keep MF on each bit 660 */ 661 if (left > 0 || not_last_frag) 662 iph->frag_off |= htons(IP_MF); 663 ptr += len; 664 offset += len; 665 666 /* 667 * Put this fragment into the sending queue. 668 */ 669 iph->tot_len = htons(len + hlen); 670 671 ip_send_check(iph); 672 673 err = output(skb2); 674 if (err) 675 goto fail; 676 677 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); 678 } 679 kfree_skb(skb); 680 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); 681 return err; 682 683 fail: 684 kfree_skb(skb); 685 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); 686 return err; 687 } 688 689 EXPORT_SYMBOL(ip_fragment); 690 691 int 692 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 693 { 694 struct iovec *iov = from; 695 696 if (skb->ip_summed == CHECKSUM_PARTIAL) { 697 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 698 return -EFAULT; 699 } else { 700 __wsum csum = 0; 701 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 702 return -EFAULT; 703 skb->csum = csum_block_add(skb->csum, csum, odd); 704 } 705 return 0; 706 } 707 708 static inline __wsum 709 csum_page(struct page *page, int offset, int copy) 710 { 711 char *kaddr; 712 __wsum csum; 713 kaddr = kmap(page); 714 csum = csum_partial(kaddr + offset, copy, 0); 715 kunmap(page); 716 return csum; 717 } 718 719 static inline int ip_ufo_append_data(struct sock *sk, 720 int getfrag(void *from, char *to, int offset, int len, 721 int odd, struct sk_buff *skb), 722 void *from, int length, int hh_len, int fragheaderlen, 723 int transhdrlen, int mtu,unsigned int flags) 724 { 725 struct sk_buff *skb; 726 int err; 727 728 /* There is support for UDP fragmentation offload by network 729 * device, so create one single skb packet containing complete 730 * udp datagram 731 */ 732 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 733 skb = sock_alloc_send_skb(sk, 734 hh_len + fragheaderlen + transhdrlen + 20, 735 (flags & MSG_DONTWAIT), &err); 736 737 if (skb == NULL) 738 return err; 739 740 /* reserve space for Hardware header */ 741 skb_reserve(skb, hh_len); 742 743 /* create space for UDP/IP header */ 744 skb_put(skb,fragheaderlen + transhdrlen); 745 746 /* initialize network header pointer */ 747 skb_reset_network_header(skb); 748 749 /* initialize protocol header pointer */ 750 skb->transport_header = skb->network_header + fragheaderlen; 751 752 skb->ip_summed = CHECKSUM_PARTIAL; 753 skb->csum = 0; 754 sk->sk_sndmsg_off = 0; 755 756 /* specify the length of each IP datagram fragment */ 757 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 758 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 759 __skb_queue_tail(&sk->sk_write_queue, skb); 760 } 761 762 return skb_append_datato_frags(sk, skb, getfrag, from, 763 (length - transhdrlen)); 764 } 765 766 /* 767 * ip_append_data() and ip_append_page() can make one large IP datagram 768 * from many pieces of data. Each pieces will be holded on the socket 769 * until ip_push_pending_frames() is called. Each piece can be a page 770 * or non-page data. 771 * 772 * Not only UDP, other transport protocols - e.g. raw sockets - can use 773 * this interface potentially. 774 * 775 * LATER: length must be adjusted by pad at tail, when it is required. 776 */ 777 int ip_append_data(struct sock *sk, 778 int getfrag(void *from, char *to, int offset, int len, 779 int odd, struct sk_buff *skb), 780 void *from, int length, int transhdrlen, 781 struct ipcm_cookie *ipc, struct rtable *rt, 782 unsigned int flags) 783 { 784 struct inet_sock *inet = inet_sk(sk); 785 struct sk_buff *skb; 786 787 struct ip_options *opt = NULL; 788 int hh_len; 789 int exthdrlen; 790 int mtu; 791 int copy; 792 int err; 793 int offset = 0; 794 unsigned int maxfraglen, fragheaderlen; 795 int csummode = CHECKSUM_NONE; 796 797 if (flags&MSG_PROBE) 798 return 0; 799 800 if (skb_queue_empty(&sk->sk_write_queue)) { 801 /* 802 * setup for corking. 803 */ 804 opt = ipc->opt; 805 if (opt) { 806 if (inet->cork.opt == NULL) { 807 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 808 if (unlikely(inet->cork.opt == NULL)) 809 return -ENOBUFS; 810 } 811 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 812 inet->cork.flags |= IPCORK_OPT; 813 inet->cork.addr = ipc->addr; 814 } 815 dst_hold(&rt->u.dst); 816 inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? 817 rt->u.dst.dev->mtu : 818 dst_mtu(rt->u.dst.path); 819 inet->cork.dst = &rt->u.dst; 820 inet->cork.length = 0; 821 sk->sk_sndmsg_page = NULL; 822 sk->sk_sndmsg_off = 0; 823 if ((exthdrlen = rt->u.dst.header_len) != 0) { 824 length += exthdrlen; 825 transhdrlen += exthdrlen; 826 } 827 } else { 828 rt = (struct rtable *)inet->cork.dst; 829 if (inet->cork.flags & IPCORK_OPT) 830 opt = inet->cork.opt; 831 832 transhdrlen = 0; 833 exthdrlen = 0; 834 mtu = inet->cork.fragsize; 835 } 836 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 837 838 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 839 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 840 841 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 842 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 843 return -EMSGSIZE; 844 } 845 846 /* 847 * transhdrlen > 0 means that this is the first fragment and we wish 848 * it won't be fragmented in the future. 849 */ 850 if (transhdrlen && 851 length + fragheaderlen <= mtu && 852 rt->u.dst.dev->features & NETIF_F_V4_CSUM && 853 !exthdrlen) 854 csummode = CHECKSUM_PARTIAL; 855 856 inet->cork.length += length; 857 if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) && 858 (sk->sk_protocol == IPPROTO_UDP) && 859 (rt->u.dst.dev->features & NETIF_F_UFO)) { 860 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 861 fragheaderlen, transhdrlen, mtu, 862 flags); 863 if (err) 864 goto error; 865 return 0; 866 } 867 868 /* So, what's going on in the loop below? 869 * 870 * We use calculated fragment length to generate chained skb, 871 * each of segments is IP fragment ready for sending to network after 872 * adding appropriate IP header. 873 */ 874 875 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 876 goto alloc_new_skb; 877 878 while (length > 0) { 879 /* Check if the remaining data fits into current packet. */ 880 copy = mtu - skb->len; 881 if (copy < length) 882 copy = maxfraglen - skb->len; 883 if (copy <= 0) { 884 char *data; 885 unsigned int datalen; 886 unsigned int fraglen; 887 unsigned int fraggap; 888 unsigned int alloclen; 889 struct sk_buff *skb_prev; 890 alloc_new_skb: 891 skb_prev = skb; 892 if (skb_prev) 893 fraggap = skb_prev->len - maxfraglen; 894 else 895 fraggap = 0; 896 897 /* 898 * If remaining data exceeds the mtu, 899 * we know we need more fragment(s). 900 */ 901 datalen = length + fraggap; 902 if (datalen > mtu - fragheaderlen) 903 datalen = maxfraglen - fragheaderlen; 904 fraglen = datalen + fragheaderlen; 905 906 if ((flags & MSG_MORE) && 907 !(rt->u.dst.dev->features&NETIF_F_SG)) 908 alloclen = mtu; 909 else 910 alloclen = datalen + fragheaderlen; 911 912 /* The last fragment gets additional space at tail. 913 * Note, with MSG_MORE we overallocate on fragments, 914 * because we have no idea what fragment will be 915 * the last. 916 */ 917 if (datalen == length + fraggap) 918 alloclen += rt->u.dst.trailer_len; 919 920 if (transhdrlen) { 921 skb = sock_alloc_send_skb(sk, 922 alloclen + hh_len + 15, 923 (flags & MSG_DONTWAIT), &err); 924 } else { 925 skb = NULL; 926 if (atomic_read(&sk->sk_wmem_alloc) <= 927 2 * sk->sk_sndbuf) 928 skb = sock_wmalloc(sk, 929 alloclen + hh_len + 15, 1, 930 sk->sk_allocation); 931 if (unlikely(skb == NULL)) 932 err = -ENOBUFS; 933 } 934 if (skb == NULL) 935 goto error; 936 937 /* 938 * Fill in the control structures 939 */ 940 skb->ip_summed = csummode; 941 skb->csum = 0; 942 skb_reserve(skb, hh_len); 943 944 /* 945 * Find where to start putting bytes. 946 */ 947 data = skb_put(skb, fraglen); 948 skb_set_network_header(skb, exthdrlen); 949 skb->transport_header = (skb->network_header + 950 fragheaderlen); 951 data += fragheaderlen; 952 953 if (fraggap) { 954 skb->csum = skb_copy_and_csum_bits( 955 skb_prev, maxfraglen, 956 data + transhdrlen, fraggap, 0); 957 skb_prev->csum = csum_sub(skb_prev->csum, 958 skb->csum); 959 data += fraggap; 960 pskb_trim_unique(skb_prev, maxfraglen); 961 } 962 963 copy = datalen - transhdrlen - fraggap; 964 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 965 err = -EFAULT; 966 kfree_skb(skb); 967 goto error; 968 } 969 970 offset += copy; 971 length -= datalen - fraggap; 972 transhdrlen = 0; 973 exthdrlen = 0; 974 csummode = CHECKSUM_NONE; 975 976 /* 977 * Put the packet on the pending queue. 978 */ 979 __skb_queue_tail(&sk->sk_write_queue, skb); 980 continue; 981 } 982 983 if (copy > length) 984 copy = length; 985 986 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 987 unsigned int off; 988 989 off = skb->len; 990 if (getfrag(from, skb_put(skb, copy), 991 offset, copy, off, skb) < 0) { 992 __skb_trim(skb, off); 993 err = -EFAULT; 994 goto error; 995 } 996 } else { 997 int i = skb_shinfo(skb)->nr_frags; 998 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 999 struct page *page = sk->sk_sndmsg_page; 1000 int off = sk->sk_sndmsg_off; 1001 unsigned int left; 1002 1003 if (page && (left = PAGE_SIZE - off) > 0) { 1004 if (copy >= left) 1005 copy = left; 1006 if (page != frag->page) { 1007 if (i == MAX_SKB_FRAGS) { 1008 err = -EMSGSIZE; 1009 goto error; 1010 } 1011 get_page(page); 1012 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1013 frag = &skb_shinfo(skb)->frags[i]; 1014 } 1015 } else if (i < MAX_SKB_FRAGS) { 1016 if (copy > PAGE_SIZE) 1017 copy = PAGE_SIZE; 1018 page = alloc_pages(sk->sk_allocation, 0); 1019 if (page == NULL) { 1020 err = -ENOMEM; 1021 goto error; 1022 } 1023 sk->sk_sndmsg_page = page; 1024 sk->sk_sndmsg_off = 0; 1025 1026 skb_fill_page_desc(skb, i, page, 0, 0); 1027 frag = &skb_shinfo(skb)->frags[i]; 1028 } else { 1029 err = -EMSGSIZE; 1030 goto error; 1031 } 1032 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1033 err = -EFAULT; 1034 goto error; 1035 } 1036 sk->sk_sndmsg_off += copy; 1037 frag->size += copy; 1038 skb->len += copy; 1039 skb->data_len += copy; 1040 skb->truesize += copy; 1041 atomic_add(copy, &sk->sk_wmem_alloc); 1042 } 1043 offset += copy; 1044 length -= copy; 1045 } 1046 1047 return 0; 1048 1049 error: 1050 inet->cork.length -= length; 1051 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1052 return err; 1053 } 1054 1055 ssize_t ip_append_page(struct sock *sk, struct page *page, 1056 int offset, size_t size, int flags) 1057 { 1058 struct inet_sock *inet = inet_sk(sk); 1059 struct sk_buff *skb; 1060 struct rtable *rt; 1061 struct ip_options *opt = NULL; 1062 int hh_len; 1063 int mtu; 1064 int len; 1065 int err; 1066 unsigned int maxfraglen, fragheaderlen, fraggap; 1067 1068 if (inet->hdrincl) 1069 return -EPERM; 1070 1071 if (flags&MSG_PROBE) 1072 return 0; 1073 1074 if (skb_queue_empty(&sk->sk_write_queue)) 1075 return -EINVAL; 1076 1077 rt = (struct rtable *)inet->cork.dst; 1078 if (inet->cork.flags & IPCORK_OPT) 1079 opt = inet->cork.opt; 1080 1081 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1082 return -EOPNOTSUPP; 1083 1084 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1085 mtu = inet->cork.fragsize; 1086 1087 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1088 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1089 1090 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1091 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1092 return -EMSGSIZE; 1093 } 1094 1095 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1096 return -EINVAL; 1097 1098 inet->cork.length += size; 1099 if ((sk->sk_protocol == IPPROTO_UDP) && 1100 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1101 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1102 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1103 } 1104 1105 1106 while (size > 0) { 1107 int i; 1108 1109 if (skb_is_gso(skb)) 1110 len = size; 1111 else { 1112 1113 /* Check if the remaining data fits into current packet. */ 1114 len = mtu - skb->len; 1115 if (len < size) 1116 len = maxfraglen - skb->len; 1117 } 1118 if (len <= 0) { 1119 struct sk_buff *skb_prev; 1120 int alloclen; 1121 1122 skb_prev = skb; 1123 fraggap = skb_prev->len - maxfraglen; 1124 1125 alloclen = fragheaderlen + hh_len + fraggap + 15; 1126 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1127 if (unlikely(!skb)) { 1128 err = -ENOBUFS; 1129 goto error; 1130 } 1131 1132 /* 1133 * Fill in the control structures 1134 */ 1135 skb->ip_summed = CHECKSUM_NONE; 1136 skb->csum = 0; 1137 skb_reserve(skb, hh_len); 1138 1139 /* 1140 * Find where to start putting bytes. 1141 */ 1142 skb_put(skb, fragheaderlen + fraggap); 1143 skb_reset_network_header(skb); 1144 skb->transport_header = (skb->network_header + 1145 fragheaderlen); 1146 if (fraggap) { 1147 skb->csum = skb_copy_and_csum_bits(skb_prev, 1148 maxfraglen, 1149 skb_transport_header(skb), 1150 fraggap, 0); 1151 skb_prev->csum = csum_sub(skb_prev->csum, 1152 skb->csum); 1153 pskb_trim_unique(skb_prev, maxfraglen); 1154 } 1155 1156 /* 1157 * Put the packet on the pending queue. 1158 */ 1159 __skb_queue_tail(&sk->sk_write_queue, skb); 1160 continue; 1161 } 1162 1163 i = skb_shinfo(skb)->nr_frags; 1164 if (len > size) 1165 len = size; 1166 if (skb_can_coalesce(skb, i, page, offset)) { 1167 skb_shinfo(skb)->frags[i-1].size += len; 1168 } else if (i < MAX_SKB_FRAGS) { 1169 get_page(page); 1170 skb_fill_page_desc(skb, i, page, offset, len); 1171 } else { 1172 err = -EMSGSIZE; 1173 goto error; 1174 } 1175 1176 if (skb->ip_summed == CHECKSUM_NONE) { 1177 __wsum csum; 1178 csum = csum_page(page, offset, len); 1179 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1180 } 1181 1182 skb->len += len; 1183 skb->data_len += len; 1184 skb->truesize += len; 1185 atomic_add(len, &sk->sk_wmem_alloc); 1186 offset += len; 1187 size -= len; 1188 } 1189 return 0; 1190 1191 error: 1192 inet->cork.length -= size; 1193 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1194 return err; 1195 } 1196 1197 static void ip_cork_release(struct inet_sock *inet) 1198 { 1199 inet->cork.flags &= ~IPCORK_OPT; 1200 kfree(inet->cork.opt); 1201 inet->cork.opt = NULL; 1202 dst_release(inet->cork.dst); 1203 inet->cork.dst = NULL; 1204 } 1205 1206 /* 1207 * Combined all pending IP fragments on the socket as one IP datagram 1208 * and push them out. 1209 */ 1210 int ip_push_pending_frames(struct sock *sk) 1211 { 1212 struct sk_buff *skb, *tmp_skb; 1213 struct sk_buff **tail_skb; 1214 struct inet_sock *inet = inet_sk(sk); 1215 struct net *net = sock_net(sk); 1216 struct ip_options *opt = NULL; 1217 struct rtable *rt = (struct rtable *)inet->cork.dst; 1218 struct iphdr *iph; 1219 __be16 df = 0; 1220 __u8 ttl; 1221 int err = 0; 1222 1223 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1224 goto out; 1225 tail_skb = &(skb_shinfo(skb)->frag_list); 1226 1227 /* move skb->data to ip header from ext header */ 1228 if (skb->data < skb_network_header(skb)) 1229 __skb_pull(skb, skb_network_offset(skb)); 1230 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1231 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1232 *tail_skb = tmp_skb; 1233 tail_skb = &(tmp_skb->next); 1234 skb->len += tmp_skb->len; 1235 skb->data_len += tmp_skb->len; 1236 skb->truesize += tmp_skb->truesize; 1237 __sock_put(tmp_skb->sk); 1238 tmp_skb->destructor = NULL; 1239 tmp_skb->sk = NULL; 1240 } 1241 1242 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1243 * to fragment the frame generated here. No matter, what transforms 1244 * how transforms change size of the packet, it will come out. 1245 */ 1246 if (inet->pmtudisc < IP_PMTUDISC_DO) 1247 skb->local_df = 1; 1248 1249 /* DF bit is set when we want to see DF on outgoing frames. 1250 * If local_df is set too, we still allow to fragment this frame 1251 * locally. */ 1252 if (inet->pmtudisc >= IP_PMTUDISC_DO || 1253 (skb->len <= dst_mtu(&rt->u.dst) && 1254 ip_dont_fragment(sk, &rt->u.dst))) 1255 df = htons(IP_DF); 1256 1257 if (inet->cork.flags & IPCORK_OPT) 1258 opt = inet->cork.opt; 1259 1260 if (rt->rt_type == RTN_MULTICAST) 1261 ttl = inet->mc_ttl; 1262 else 1263 ttl = ip_select_ttl(inet, &rt->u.dst); 1264 1265 iph = (struct iphdr *)skb->data; 1266 iph->version = 4; 1267 iph->ihl = 5; 1268 if (opt) { 1269 iph->ihl += opt->optlen>>2; 1270 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1271 } 1272 iph->tos = inet->tos; 1273 iph->frag_off = df; 1274 ip_select_ident(iph, &rt->u.dst, sk); 1275 iph->ttl = ttl; 1276 iph->protocol = sk->sk_protocol; 1277 iph->saddr = rt->rt_src; 1278 iph->daddr = rt->rt_dst; 1279 1280 skb->priority = sk->sk_priority; 1281 skb->mark = sk->sk_mark; 1282 skb->dst = dst_clone(&rt->u.dst); 1283 1284 if (iph->protocol == IPPROTO_ICMP) 1285 icmp_out_count(net, ((struct icmphdr *) 1286 skb_transport_header(skb))->type); 1287 1288 /* Netfilter gets whole the not fragmented skb. */ 1289 err = ip_local_out(skb); 1290 if (err) { 1291 if (err > 0) 1292 err = inet->recverr ? net_xmit_errno(err) : 0; 1293 if (err) 1294 goto error; 1295 } 1296 1297 out: 1298 ip_cork_release(inet); 1299 return err; 1300 1301 error: 1302 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); 1303 goto out; 1304 } 1305 1306 /* 1307 * Throw away all pending data on the socket. 1308 */ 1309 void ip_flush_pending_frames(struct sock *sk) 1310 { 1311 struct sk_buff *skb; 1312 1313 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1314 kfree_skb(skb); 1315 1316 ip_cork_release(inet_sk(sk)); 1317 } 1318 1319 1320 /* 1321 * Fetch data from kernel space and fill in checksum if needed. 1322 */ 1323 static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1324 int len, int odd, struct sk_buff *skb) 1325 { 1326 __wsum csum; 1327 1328 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1329 skb->csum = csum_block_add(skb->csum, csum, odd); 1330 return 0; 1331 } 1332 1333 /* 1334 * Generic function to send a packet as reply to another packet. 1335 * Used to send TCP resets so far. ICMP should use this function too. 1336 * 1337 * Should run single threaded per socket because it uses the sock 1338 * structure to pass arguments. 1339 */ 1340 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1341 unsigned int len) 1342 { 1343 struct inet_sock *inet = inet_sk(sk); 1344 struct { 1345 struct ip_options opt; 1346 char data[40]; 1347 } replyopts; 1348 struct ipcm_cookie ipc; 1349 __be32 daddr; 1350 struct rtable *rt = skb->rtable; 1351 1352 if (ip_options_echo(&replyopts.opt, skb)) 1353 return; 1354 1355 daddr = ipc.addr = rt->rt_src; 1356 ipc.opt = NULL; 1357 1358 if (replyopts.opt.optlen) { 1359 ipc.opt = &replyopts.opt; 1360 1361 if (ipc.opt->srr) 1362 daddr = replyopts.opt.faddr; 1363 } 1364 1365 { 1366 struct flowi fl = { .oif = arg->bound_dev_if, 1367 .nl_u = { .ip4_u = 1368 { .daddr = daddr, 1369 .saddr = rt->rt_spec_dst, 1370 .tos = RT_TOS(ip_hdr(skb)->tos) } }, 1371 /* Not quite clean, but right. */ 1372 .uli_u = { .ports = 1373 { .sport = tcp_hdr(skb)->dest, 1374 .dport = tcp_hdr(skb)->source } }, 1375 .proto = sk->sk_protocol, 1376 .flags = ip_reply_arg_flowi_flags(arg) }; 1377 security_skb_classify_flow(skb, &fl); 1378 if (ip_route_output_key(sock_net(sk), &rt, &fl)) 1379 return; 1380 } 1381 1382 /* And let IP do all the hard work. 1383 1384 This chunk is not reenterable, hence spinlock. 1385 Note that it uses the fact, that this function is called 1386 with locally disabled BH and that sk cannot be already spinlocked. 1387 */ 1388 bh_lock_sock(sk); 1389 inet->tos = ip_hdr(skb)->tos; 1390 sk->sk_priority = skb->priority; 1391 sk->sk_protocol = ip_hdr(skb)->protocol; 1392 sk->sk_bound_dev_if = arg->bound_dev_if; 1393 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1394 &ipc, rt, MSG_DONTWAIT); 1395 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1396 if (arg->csumoffset >= 0) 1397 *((__sum16 *)skb_transport_header(skb) + 1398 arg->csumoffset) = csum_fold(csum_add(skb->csum, 1399 arg->csum)); 1400 skb->ip_summed = CHECKSUM_NONE; 1401 ip_push_pending_frames(sk); 1402 } 1403 1404 bh_unlock_sock(sk); 1405 1406 ip_rt_put(rt); 1407 } 1408 1409 void __init ip_init(void) 1410 { 1411 ip_rt_init(); 1412 inet_initpeers(); 1413 1414 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1415 igmp_mc_proc_init(); 1416 #endif 1417 } 1418 1419 EXPORT_SYMBOL(ip_generic_getfrag); 1420 EXPORT_SYMBOL(ip_queue_xmit); 1421 EXPORT_SYMBOL(ip_send_check); 1422