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(skb)->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(!skb_dst(newskb)); 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(skb); 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(skb); 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_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len); 186 } else if (rt->rt_type == RTN_BROADCAST) 187 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len); 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(skb)->dev->mtu : dst_mtu(skb_dst(skb)); 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(skb)->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(skb); 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_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); 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(skb)->dev; 300 301 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); 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(skb); 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_set(skb, 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 skb_dst_drop(to); 405 skb_dst_set(to, dst_clone(skb_dst(from))); 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(skb); 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_has_frags(skb)) { 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 skb_walk_frags(skb, frag) { 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 frag->sk = skb->sk; 502 frag->destructor = sock_wfree; 503 truesizes += frag->truesize; 504 } 505 } 506 507 /* Everything is OK. Generate! */ 508 509 err = 0; 510 offset = 0; 511 frag = skb_shinfo(skb)->frag_list; 512 skb_frag_list_init(skb); 513 skb->data_len = first_len - skb_headlen(skb); 514 skb->truesize -= truesizes; 515 skb->len = first_len; 516 iph->tot_len = htons(first_len); 517 iph->frag_off = htons(IP_MF); 518 ip_send_check(iph); 519 520 for (;;) { 521 /* Prepare header of the next frame, 522 * before previous one went down. */ 523 if (frag) { 524 frag->ip_summed = CHECKSUM_NONE; 525 skb_reset_transport_header(frag); 526 __skb_push(frag, hlen); 527 skb_reset_network_header(frag); 528 memcpy(skb_network_header(frag), iph, hlen); 529 iph = ip_hdr(frag); 530 iph->tot_len = htons(frag->len); 531 ip_copy_metadata(frag, skb); 532 if (offset == 0) 533 ip_options_fragment(frag); 534 offset += skb->len - hlen; 535 iph->frag_off = htons(offset>>3); 536 if (frag->next != NULL) 537 iph->frag_off |= htons(IP_MF); 538 /* Ready, complete checksum */ 539 ip_send_check(iph); 540 } 541 542 err = output(skb); 543 544 if (!err) 545 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); 546 if (err || !frag) 547 break; 548 549 skb = frag; 550 frag = skb->next; 551 skb->next = NULL; 552 } 553 554 if (err == 0) { 555 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); 556 return 0; 557 } 558 559 while (frag) { 560 skb = frag->next; 561 kfree_skb(frag); 562 frag = skb; 563 } 564 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); 565 return err; 566 } 567 568 slow_path: 569 left = skb->len - hlen; /* Space per frame */ 570 ptr = raw + hlen; /* Where to start from */ 571 572 /* for bridged IP traffic encapsulated inside f.e. a vlan header, 573 * we need to make room for the encapsulating header 574 */ 575 pad = nf_bridge_pad(skb); 576 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad); 577 mtu -= pad; 578 579 /* 580 * Fragment the datagram. 581 */ 582 583 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; 584 not_last_frag = iph->frag_off & htons(IP_MF); 585 586 /* 587 * Keep copying data until we run out. 588 */ 589 590 while (left > 0) { 591 len = left; 592 /* IF: it doesn't fit, use 'mtu' - the data space left */ 593 if (len > mtu) 594 len = mtu; 595 /* IF: we are not sending upto and including the packet end 596 then align the next start on an eight byte boundary */ 597 if (len < left) { 598 len &= ~7; 599 } 600 /* 601 * Allocate buffer. 602 */ 603 604 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { 605 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); 606 err = -ENOMEM; 607 goto fail; 608 } 609 610 /* 611 * Set up data on packet 612 */ 613 614 ip_copy_metadata(skb2, skb); 615 skb_reserve(skb2, ll_rs); 616 skb_put(skb2, len + hlen); 617 skb_reset_network_header(skb2); 618 skb2->transport_header = skb2->network_header + hlen; 619 620 /* 621 * Charge the memory for the fragment to any owner 622 * it might possess 623 */ 624 625 if (skb->sk) 626 skb_set_owner_w(skb2, skb->sk); 627 628 /* 629 * Copy the packet header into the new buffer. 630 */ 631 632 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); 633 634 /* 635 * Copy a block of the IP datagram. 636 */ 637 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) 638 BUG(); 639 left -= len; 640 641 /* 642 * Fill in the new header fields. 643 */ 644 iph = ip_hdr(skb2); 645 iph->frag_off = htons((offset >> 3)); 646 647 /* ANK: dirty, but effective trick. Upgrade options only if 648 * the segment to be fragmented was THE FIRST (otherwise, 649 * options are already fixed) and make it ONCE 650 * on the initial skb, so that all the following fragments 651 * will inherit fixed options. 652 */ 653 if (offset == 0) 654 ip_options_fragment(skb); 655 656 /* 657 * Added AC : If we are fragmenting a fragment that's not the 658 * last fragment then keep MF on each bit 659 */ 660 if (left > 0 || not_last_frag) 661 iph->frag_off |= htons(IP_MF); 662 ptr += len; 663 offset += len; 664 665 /* 666 * Put this fragment into the sending queue. 667 */ 668 iph->tot_len = htons(len + hlen); 669 670 ip_send_check(iph); 671 672 err = output(skb2); 673 if (err) 674 goto fail; 675 676 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); 677 } 678 kfree_skb(skb); 679 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); 680 return err; 681 682 fail: 683 kfree_skb(skb); 684 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); 685 return err; 686 } 687 688 EXPORT_SYMBOL(ip_fragment); 689 690 int 691 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 692 { 693 struct iovec *iov = from; 694 695 if (skb->ip_summed == CHECKSUM_PARTIAL) { 696 if (memcpy_fromiovecend(to, iov, offset, len) < 0) 697 return -EFAULT; 698 } else { 699 __wsum csum = 0; 700 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) 701 return -EFAULT; 702 skb->csum = csum_block_add(skb->csum, csum, odd); 703 } 704 return 0; 705 } 706 707 static inline __wsum 708 csum_page(struct page *page, int offset, int copy) 709 { 710 char *kaddr; 711 __wsum csum; 712 kaddr = kmap(page); 713 csum = csum_partial(kaddr + offset, copy, 0); 714 kunmap(page); 715 return csum; 716 } 717 718 static inline int ip_ufo_append_data(struct sock *sk, 719 int getfrag(void *from, char *to, int offset, int len, 720 int odd, struct sk_buff *skb), 721 void *from, int length, int hh_len, int fragheaderlen, 722 int transhdrlen, int mtu, unsigned int flags) 723 { 724 struct sk_buff *skb; 725 int err; 726 727 /* There is support for UDP fragmentation offload by network 728 * device, so create one single skb packet containing complete 729 * udp datagram 730 */ 731 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { 732 skb = sock_alloc_send_skb(sk, 733 hh_len + fragheaderlen + transhdrlen + 20, 734 (flags & MSG_DONTWAIT), &err); 735 736 if (skb == NULL) 737 return err; 738 739 /* reserve space for Hardware header */ 740 skb_reserve(skb, hh_len); 741 742 /* create space for UDP/IP header */ 743 skb_put(skb, fragheaderlen + transhdrlen); 744 745 /* initialize network header pointer */ 746 skb_reset_network_header(skb); 747 748 /* initialize protocol header pointer */ 749 skb->transport_header = skb->network_header + fragheaderlen; 750 751 skb->ip_summed = CHECKSUM_PARTIAL; 752 skb->csum = 0; 753 sk->sk_sndmsg_off = 0; 754 755 /* specify the length of each IP datagram fragment */ 756 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 757 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 758 __skb_queue_tail(&sk->sk_write_queue, skb); 759 } 760 761 return skb_append_datato_frags(sk, skb, getfrag, from, 762 (length - transhdrlen)); 763 } 764 765 /* 766 * ip_append_data() and ip_append_page() can make one large IP datagram 767 * from many pieces of data. Each pieces will be holded on the socket 768 * until ip_push_pending_frames() is called. Each piece can be a page 769 * or non-page data. 770 * 771 * Not only UDP, other transport protocols - e.g. raw sockets - can use 772 * this interface potentially. 773 * 774 * LATER: length must be adjusted by pad at tail, when it is required. 775 */ 776 int ip_append_data(struct sock *sk, 777 int getfrag(void *from, char *to, int offset, int len, 778 int odd, struct sk_buff *skb), 779 void *from, int length, int transhdrlen, 780 struct ipcm_cookie *ipc, struct rtable **rtp, 781 unsigned int flags) 782 { 783 struct inet_sock *inet = inet_sk(sk); 784 struct sk_buff *skb; 785 786 struct ip_options *opt = NULL; 787 int hh_len; 788 int exthdrlen; 789 int mtu; 790 int copy; 791 int err; 792 int offset = 0; 793 unsigned int maxfraglen, fragheaderlen; 794 int csummode = CHECKSUM_NONE; 795 struct rtable *rt; 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 rt = *rtp; 816 /* 817 * We steal reference to this route, caller should not release it 818 */ 819 *rtp = NULL; 820 inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? 821 rt->u.dst.dev->mtu : 822 dst_mtu(rt->u.dst.path); 823 inet->cork.dst = &rt->u.dst; 824 inet->cork.length = 0; 825 sk->sk_sndmsg_page = NULL; 826 sk->sk_sndmsg_off = 0; 827 if ((exthdrlen = rt->u.dst.header_len) != 0) { 828 length += exthdrlen; 829 transhdrlen += exthdrlen; 830 } 831 } else { 832 rt = (struct rtable *)inet->cork.dst; 833 if (inet->cork.flags & IPCORK_OPT) 834 opt = inet->cork.opt; 835 836 transhdrlen = 0; 837 exthdrlen = 0; 838 mtu = inet->cork.fragsize; 839 } 840 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 841 842 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 843 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 844 845 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 846 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 847 return -EMSGSIZE; 848 } 849 850 /* 851 * transhdrlen > 0 means that this is the first fragment and we wish 852 * it won't be fragmented in the future. 853 */ 854 if (transhdrlen && 855 length + fragheaderlen <= mtu && 856 rt->u.dst.dev->features & NETIF_F_V4_CSUM && 857 !exthdrlen) 858 csummode = CHECKSUM_PARTIAL; 859 860 inet->cork.length += length; 861 if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) && 862 (sk->sk_protocol == IPPROTO_UDP) && 863 (rt->u.dst.dev->features & NETIF_F_UFO)) { 864 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 865 fragheaderlen, transhdrlen, mtu, 866 flags); 867 if (err) 868 goto error; 869 return 0; 870 } 871 872 /* So, what's going on in the loop below? 873 * 874 * We use calculated fragment length to generate chained skb, 875 * each of segments is IP fragment ready for sending to network after 876 * adding appropriate IP header. 877 */ 878 879 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 880 goto alloc_new_skb; 881 882 while (length > 0) { 883 /* Check if the remaining data fits into current packet. */ 884 copy = mtu - skb->len; 885 if (copy < length) 886 copy = maxfraglen - skb->len; 887 if (copy <= 0) { 888 char *data; 889 unsigned int datalen; 890 unsigned int fraglen; 891 unsigned int fraggap; 892 unsigned int alloclen; 893 struct sk_buff *skb_prev; 894 alloc_new_skb: 895 skb_prev = skb; 896 if (skb_prev) 897 fraggap = skb_prev->len - maxfraglen; 898 else 899 fraggap = 0; 900 901 /* 902 * If remaining data exceeds the mtu, 903 * we know we need more fragment(s). 904 */ 905 datalen = length + fraggap; 906 if (datalen > mtu - fragheaderlen) 907 datalen = maxfraglen - fragheaderlen; 908 fraglen = datalen + fragheaderlen; 909 910 if ((flags & MSG_MORE) && 911 !(rt->u.dst.dev->features&NETIF_F_SG)) 912 alloclen = mtu; 913 else 914 alloclen = datalen + fragheaderlen; 915 916 /* The last fragment gets additional space at tail. 917 * Note, with MSG_MORE we overallocate on fragments, 918 * because we have no idea what fragment will be 919 * the last. 920 */ 921 if (datalen == length + fraggap) 922 alloclen += rt->u.dst.trailer_len; 923 924 if (transhdrlen) { 925 skb = sock_alloc_send_skb(sk, 926 alloclen + hh_len + 15, 927 (flags & MSG_DONTWAIT), &err); 928 } else { 929 skb = NULL; 930 if (atomic_read(&sk->sk_wmem_alloc) <= 931 2 * sk->sk_sndbuf) 932 skb = sock_wmalloc(sk, 933 alloclen + hh_len + 15, 1, 934 sk->sk_allocation); 935 if (unlikely(skb == NULL)) 936 err = -ENOBUFS; 937 else 938 /* only the initial fragment is 939 time stamped */ 940 ipc->shtx.flags = 0; 941 } 942 if (skb == NULL) 943 goto error; 944 945 /* 946 * Fill in the control structures 947 */ 948 skb->ip_summed = csummode; 949 skb->csum = 0; 950 skb_reserve(skb, hh_len); 951 *skb_tx(skb) = ipc->shtx; 952 953 /* 954 * Find where to start putting bytes. 955 */ 956 data = skb_put(skb, fraglen); 957 skb_set_network_header(skb, exthdrlen); 958 skb->transport_header = (skb->network_header + 959 fragheaderlen); 960 data += fragheaderlen; 961 962 if (fraggap) { 963 skb->csum = skb_copy_and_csum_bits( 964 skb_prev, maxfraglen, 965 data + transhdrlen, fraggap, 0); 966 skb_prev->csum = csum_sub(skb_prev->csum, 967 skb->csum); 968 data += fraggap; 969 pskb_trim_unique(skb_prev, maxfraglen); 970 } 971 972 copy = datalen - transhdrlen - fraggap; 973 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 974 err = -EFAULT; 975 kfree_skb(skb); 976 goto error; 977 } 978 979 offset += copy; 980 length -= datalen - fraggap; 981 transhdrlen = 0; 982 exthdrlen = 0; 983 csummode = CHECKSUM_NONE; 984 985 /* 986 * Put the packet on the pending queue. 987 */ 988 __skb_queue_tail(&sk->sk_write_queue, skb); 989 continue; 990 } 991 992 if (copy > length) 993 copy = length; 994 995 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 996 unsigned int off; 997 998 off = skb->len; 999 if (getfrag(from, skb_put(skb, copy), 1000 offset, copy, off, skb) < 0) { 1001 __skb_trim(skb, off); 1002 err = -EFAULT; 1003 goto error; 1004 } 1005 } else { 1006 int i = skb_shinfo(skb)->nr_frags; 1007 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1008 struct page *page = sk->sk_sndmsg_page; 1009 int off = sk->sk_sndmsg_off; 1010 unsigned int left; 1011 1012 if (page && (left = PAGE_SIZE - off) > 0) { 1013 if (copy >= left) 1014 copy = left; 1015 if (page != frag->page) { 1016 if (i == MAX_SKB_FRAGS) { 1017 err = -EMSGSIZE; 1018 goto error; 1019 } 1020 get_page(page); 1021 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1022 frag = &skb_shinfo(skb)->frags[i]; 1023 } 1024 } else if (i < MAX_SKB_FRAGS) { 1025 if (copy > PAGE_SIZE) 1026 copy = PAGE_SIZE; 1027 page = alloc_pages(sk->sk_allocation, 0); 1028 if (page == NULL) { 1029 err = -ENOMEM; 1030 goto error; 1031 } 1032 sk->sk_sndmsg_page = page; 1033 sk->sk_sndmsg_off = 0; 1034 1035 skb_fill_page_desc(skb, i, page, 0, 0); 1036 frag = &skb_shinfo(skb)->frags[i]; 1037 } else { 1038 err = -EMSGSIZE; 1039 goto error; 1040 } 1041 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1042 err = -EFAULT; 1043 goto error; 1044 } 1045 sk->sk_sndmsg_off += copy; 1046 frag->size += copy; 1047 skb->len += copy; 1048 skb->data_len += copy; 1049 skb->truesize += copy; 1050 atomic_add(copy, &sk->sk_wmem_alloc); 1051 } 1052 offset += copy; 1053 length -= copy; 1054 } 1055 1056 return 0; 1057 1058 error: 1059 inet->cork.length -= length; 1060 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1061 return err; 1062 } 1063 1064 ssize_t ip_append_page(struct sock *sk, struct page *page, 1065 int offset, size_t size, int flags) 1066 { 1067 struct inet_sock *inet = inet_sk(sk); 1068 struct sk_buff *skb; 1069 struct rtable *rt; 1070 struct ip_options *opt = NULL; 1071 int hh_len; 1072 int mtu; 1073 int len; 1074 int err; 1075 unsigned int maxfraglen, fragheaderlen, fraggap; 1076 1077 if (inet->hdrincl) 1078 return -EPERM; 1079 1080 if (flags&MSG_PROBE) 1081 return 0; 1082 1083 if (skb_queue_empty(&sk->sk_write_queue)) 1084 return -EINVAL; 1085 1086 rt = (struct rtable *)inet->cork.dst; 1087 if (inet->cork.flags & IPCORK_OPT) 1088 opt = inet->cork.opt; 1089 1090 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1091 return -EOPNOTSUPP; 1092 1093 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1094 mtu = inet->cork.fragsize; 1095 1096 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1097 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1098 1099 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1100 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1101 return -EMSGSIZE; 1102 } 1103 1104 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1105 return -EINVAL; 1106 1107 inet->cork.length += size; 1108 if ((sk->sk_protocol == IPPROTO_UDP) && 1109 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1110 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1111 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1112 } 1113 1114 1115 while (size > 0) { 1116 int i; 1117 1118 if (skb_is_gso(skb)) 1119 len = size; 1120 else { 1121 1122 /* Check if the remaining data fits into current packet. */ 1123 len = mtu - skb->len; 1124 if (len < size) 1125 len = maxfraglen - skb->len; 1126 } 1127 if (len <= 0) { 1128 struct sk_buff *skb_prev; 1129 int alloclen; 1130 1131 skb_prev = skb; 1132 fraggap = skb_prev->len - maxfraglen; 1133 1134 alloclen = fragheaderlen + hh_len + fraggap + 15; 1135 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1136 if (unlikely(!skb)) { 1137 err = -ENOBUFS; 1138 goto error; 1139 } 1140 1141 /* 1142 * Fill in the control structures 1143 */ 1144 skb->ip_summed = CHECKSUM_NONE; 1145 skb->csum = 0; 1146 skb_reserve(skb, hh_len); 1147 1148 /* 1149 * Find where to start putting bytes. 1150 */ 1151 skb_put(skb, fragheaderlen + fraggap); 1152 skb_reset_network_header(skb); 1153 skb->transport_header = (skb->network_header + 1154 fragheaderlen); 1155 if (fraggap) { 1156 skb->csum = skb_copy_and_csum_bits(skb_prev, 1157 maxfraglen, 1158 skb_transport_header(skb), 1159 fraggap, 0); 1160 skb_prev->csum = csum_sub(skb_prev->csum, 1161 skb->csum); 1162 pskb_trim_unique(skb_prev, maxfraglen); 1163 } 1164 1165 /* 1166 * Put the packet on the pending queue. 1167 */ 1168 __skb_queue_tail(&sk->sk_write_queue, skb); 1169 continue; 1170 } 1171 1172 i = skb_shinfo(skb)->nr_frags; 1173 if (len > size) 1174 len = size; 1175 if (skb_can_coalesce(skb, i, page, offset)) { 1176 skb_shinfo(skb)->frags[i-1].size += len; 1177 } else if (i < MAX_SKB_FRAGS) { 1178 get_page(page); 1179 skb_fill_page_desc(skb, i, page, offset, len); 1180 } else { 1181 err = -EMSGSIZE; 1182 goto error; 1183 } 1184 1185 if (skb->ip_summed == CHECKSUM_NONE) { 1186 __wsum csum; 1187 csum = csum_page(page, offset, len); 1188 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1189 } 1190 1191 skb->len += len; 1192 skb->data_len += len; 1193 skb->truesize += len; 1194 atomic_add(len, &sk->sk_wmem_alloc); 1195 offset += len; 1196 size -= len; 1197 } 1198 return 0; 1199 1200 error: 1201 inet->cork.length -= size; 1202 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1203 return err; 1204 } 1205 1206 static void ip_cork_release(struct inet_sock *inet) 1207 { 1208 inet->cork.flags &= ~IPCORK_OPT; 1209 kfree(inet->cork.opt); 1210 inet->cork.opt = NULL; 1211 dst_release(inet->cork.dst); 1212 inet->cork.dst = NULL; 1213 } 1214 1215 /* 1216 * Combined all pending IP fragments on the socket as one IP datagram 1217 * and push them out. 1218 */ 1219 int ip_push_pending_frames(struct sock *sk) 1220 { 1221 struct sk_buff *skb, *tmp_skb; 1222 struct sk_buff **tail_skb; 1223 struct inet_sock *inet = inet_sk(sk); 1224 struct net *net = sock_net(sk); 1225 struct ip_options *opt = NULL; 1226 struct rtable *rt = (struct rtable *)inet->cork.dst; 1227 struct iphdr *iph; 1228 __be16 df = 0; 1229 __u8 ttl; 1230 int err = 0; 1231 1232 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1233 goto out; 1234 tail_skb = &(skb_shinfo(skb)->frag_list); 1235 1236 /* move skb->data to ip header from ext header */ 1237 if (skb->data < skb_network_header(skb)) 1238 __skb_pull(skb, skb_network_offset(skb)); 1239 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1240 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1241 *tail_skb = tmp_skb; 1242 tail_skb = &(tmp_skb->next); 1243 skb->len += tmp_skb->len; 1244 skb->data_len += tmp_skb->len; 1245 skb->truesize += tmp_skb->truesize; 1246 tmp_skb->destructor = NULL; 1247 tmp_skb->sk = NULL; 1248 } 1249 1250 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1251 * to fragment the frame generated here. No matter, what transforms 1252 * how transforms change size of the packet, it will come out. 1253 */ 1254 if (inet->pmtudisc < IP_PMTUDISC_DO) 1255 skb->local_df = 1; 1256 1257 /* DF bit is set when we want to see DF on outgoing frames. 1258 * If local_df is set too, we still allow to fragment this frame 1259 * locally. */ 1260 if (inet->pmtudisc >= IP_PMTUDISC_DO || 1261 (skb->len <= dst_mtu(&rt->u.dst) && 1262 ip_dont_fragment(sk, &rt->u.dst))) 1263 df = htons(IP_DF); 1264 1265 if (inet->cork.flags & IPCORK_OPT) 1266 opt = inet->cork.opt; 1267 1268 if (rt->rt_type == RTN_MULTICAST) 1269 ttl = inet->mc_ttl; 1270 else 1271 ttl = ip_select_ttl(inet, &rt->u.dst); 1272 1273 iph = (struct iphdr *)skb->data; 1274 iph->version = 4; 1275 iph->ihl = 5; 1276 if (opt) { 1277 iph->ihl += opt->optlen>>2; 1278 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1279 } 1280 iph->tos = inet->tos; 1281 iph->frag_off = df; 1282 ip_select_ident(iph, &rt->u.dst, sk); 1283 iph->ttl = ttl; 1284 iph->protocol = sk->sk_protocol; 1285 iph->saddr = rt->rt_src; 1286 iph->daddr = rt->rt_dst; 1287 1288 skb->priority = sk->sk_priority; 1289 skb->mark = sk->sk_mark; 1290 /* 1291 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec 1292 * on dst refcount 1293 */ 1294 inet->cork.dst = NULL; 1295 skb_dst_set(skb, &rt->u.dst); 1296 1297 if (iph->protocol == IPPROTO_ICMP) 1298 icmp_out_count(net, ((struct icmphdr *) 1299 skb_transport_header(skb))->type); 1300 1301 /* Netfilter gets whole the not fragmented skb. */ 1302 err = ip_local_out(skb); 1303 if (err) { 1304 if (err > 0) 1305 err = inet->recverr ? net_xmit_errno(err) : 0; 1306 if (err) 1307 goto error; 1308 } 1309 1310 out: 1311 ip_cork_release(inet); 1312 return err; 1313 1314 error: 1315 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); 1316 goto out; 1317 } 1318 1319 /* 1320 * Throw away all pending data on the socket. 1321 */ 1322 void ip_flush_pending_frames(struct sock *sk) 1323 { 1324 struct sk_buff *skb; 1325 1326 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1327 kfree_skb(skb); 1328 1329 ip_cork_release(inet_sk(sk)); 1330 } 1331 1332 1333 /* 1334 * Fetch data from kernel space and fill in checksum if needed. 1335 */ 1336 static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1337 int len, int odd, struct sk_buff *skb) 1338 { 1339 __wsum csum; 1340 1341 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1342 skb->csum = csum_block_add(skb->csum, csum, odd); 1343 return 0; 1344 } 1345 1346 /* 1347 * Generic function to send a packet as reply to another packet. 1348 * Used to send TCP resets so far. ICMP should use this function too. 1349 * 1350 * Should run single threaded per socket because it uses the sock 1351 * structure to pass arguments. 1352 */ 1353 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1354 unsigned int len) 1355 { 1356 struct inet_sock *inet = inet_sk(sk); 1357 struct { 1358 struct ip_options opt; 1359 char data[40]; 1360 } replyopts; 1361 struct ipcm_cookie ipc; 1362 __be32 daddr; 1363 struct rtable *rt = skb_rtable(skb); 1364 1365 if (ip_options_echo(&replyopts.opt, skb)) 1366 return; 1367 1368 daddr = ipc.addr = rt->rt_src; 1369 ipc.opt = NULL; 1370 ipc.shtx.flags = 0; 1371 1372 if (replyopts.opt.optlen) { 1373 ipc.opt = &replyopts.opt; 1374 1375 if (ipc.opt->srr) 1376 daddr = replyopts.opt.faddr; 1377 } 1378 1379 { 1380 struct flowi fl = { .oif = arg->bound_dev_if, 1381 .nl_u = { .ip4_u = 1382 { .daddr = daddr, 1383 .saddr = rt->rt_spec_dst, 1384 .tos = RT_TOS(ip_hdr(skb)->tos) } }, 1385 /* Not quite clean, but right. */ 1386 .uli_u = { .ports = 1387 { .sport = tcp_hdr(skb)->dest, 1388 .dport = tcp_hdr(skb)->source } }, 1389 .proto = sk->sk_protocol, 1390 .flags = ip_reply_arg_flowi_flags(arg) }; 1391 security_skb_classify_flow(skb, &fl); 1392 if (ip_route_output_key(sock_net(sk), &rt, &fl)) 1393 return; 1394 } 1395 1396 /* And let IP do all the hard work. 1397 1398 This chunk is not reenterable, hence spinlock. 1399 Note that it uses the fact, that this function is called 1400 with locally disabled BH and that sk cannot be already spinlocked. 1401 */ 1402 bh_lock_sock(sk); 1403 inet->tos = ip_hdr(skb)->tos; 1404 sk->sk_priority = skb->priority; 1405 sk->sk_protocol = ip_hdr(skb)->protocol; 1406 sk->sk_bound_dev_if = arg->bound_dev_if; 1407 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1408 &ipc, &rt, MSG_DONTWAIT); 1409 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1410 if (arg->csumoffset >= 0) 1411 *((__sum16 *)skb_transport_header(skb) + 1412 arg->csumoffset) = csum_fold(csum_add(skb->csum, 1413 arg->csum)); 1414 skb->ip_summed = CHECKSUM_NONE; 1415 ip_push_pending_frames(sk); 1416 } 1417 1418 bh_unlock_sock(sk); 1419 1420 ip_rt_put(rt); 1421 } 1422 1423 void __init ip_init(void) 1424 { 1425 ip_rt_init(); 1426 inet_initpeers(); 1427 1428 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1429 igmp_mc_proc_init(); 1430 #endif 1431 } 1432 1433 EXPORT_SYMBOL(ip_generic_getfrag); 1434 EXPORT_SYMBOL(ip_queue_xmit); 1435 EXPORT_SYMBOL(ip_send_check); 1436