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 **rtp, 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 struct rtable *rt; 797 798 if (flags&MSG_PROBE) 799 return 0; 800 801 if (skb_queue_empty(&sk->sk_write_queue)) { 802 /* 803 * setup for corking. 804 */ 805 opt = ipc->opt; 806 if (opt) { 807 if (inet->cork.opt == NULL) { 808 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); 809 if (unlikely(inet->cork.opt == NULL)) 810 return -ENOBUFS; 811 } 812 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); 813 inet->cork.flags |= IPCORK_OPT; 814 inet->cork.addr = ipc->addr; 815 } 816 rt = *rtp; 817 /* 818 * We steal reference to this route, caller should not release it 819 */ 820 *rtp = NULL; 821 inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? 822 rt->u.dst.dev->mtu : 823 dst_mtu(rt->u.dst.path); 824 inet->cork.dst = &rt->u.dst; 825 inet->cork.length = 0; 826 sk->sk_sndmsg_page = NULL; 827 sk->sk_sndmsg_off = 0; 828 if ((exthdrlen = rt->u.dst.header_len) != 0) { 829 length += exthdrlen; 830 transhdrlen += exthdrlen; 831 } 832 } else { 833 rt = (struct rtable *)inet->cork.dst; 834 if (inet->cork.flags & IPCORK_OPT) 835 opt = inet->cork.opt; 836 837 transhdrlen = 0; 838 exthdrlen = 0; 839 mtu = inet->cork.fragsize; 840 } 841 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 842 843 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 844 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 845 846 if (inet->cork.length + length > 0xFFFF - fragheaderlen) { 847 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); 848 return -EMSGSIZE; 849 } 850 851 /* 852 * transhdrlen > 0 means that this is the first fragment and we wish 853 * it won't be fragmented in the future. 854 */ 855 if (transhdrlen && 856 length + fragheaderlen <= mtu && 857 rt->u.dst.dev->features & NETIF_F_V4_CSUM && 858 !exthdrlen) 859 csummode = CHECKSUM_PARTIAL; 860 861 inet->cork.length += length; 862 if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) && 863 (sk->sk_protocol == IPPROTO_UDP) && 864 (rt->u.dst.dev->features & NETIF_F_UFO)) { 865 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, 866 fragheaderlen, transhdrlen, mtu, 867 flags); 868 if (err) 869 goto error; 870 return 0; 871 } 872 873 /* So, what's going on in the loop below? 874 * 875 * We use calculated fragment length to generate chained skb, 876 * each of segments is IP fragment ready for sending to network after 877 * adding appropriate IP header. 878 */ 879 880 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 881 goto alloc_new_skb; 882 883 while (length > 0) { 884 /* Check if the remaining data fits into current packet. */ 885 copy = mtu - skb->len; 886 if (copy < length) 887 copy = maxfraglen - skb->len; 888 if (copy <= 0) { 889 char *data; 890 unsigned int datalen; 891 unsigned int fraglen; 892 unsigned int fraggap; 893 unsigned int alloclen; 894 struct sk_buff *skb_prev; 895 alloc_new_skb: 896 skb_prev = skb; 897 if (skb_prev) 898 fraggap = skb_prev->len - maxfraglen; 899 else 900 fraggap = 0; 901 902 /* 903 * If remaining data exceeds the mtu, 904 * we know we need more fragment(s). 905 */ 906 datalen = length + fraggap; 907 if (datalen > mtu - fragheaderlen) 908 datalen = maxfraglen - fragheaderlen; 909 fraglen = datalen + fragheaderlen; 910 911 if ((flags & MSG_MORE) && 912 !(rt->u.dst.dev->features&NETIF_F_SG)) 913 alloclen = mtu; 914 else 915 alloclen = datalen + fragheaderlen; 916 917 /* The last fragment gets additional space at tail. 918 * Note, with MSG_MORE we overallocate on fragments, 919 * because we have no idea what fragment will be 920 * the last. 921 */ 922 if (datalen == length + fraggap) 923 alloclen += rt->u.dst.trailer_len; 924 925 if (transhdrlen) { 926 skb = sock_alloc_send_skb(sk, 927 alloclen + hh_len + 15, 928 (flags & MSG_DONTWAIT), &err); 929 } else { 930 skb = NULL; 931 if (atomic_read(&sk->sk_wmem_alloc) <= 932 2 * sk->sk_sndbuf) 933 skb = sock_wmalloc(sk, 934 alloclen + hh_len + 15, 1, 935 sk->sk_allocation); 936 if (unlikely(skb == NULL)) 937 err = -ENOBUFS; 938 else 939 /* only the initial fragment is 940 time stamped */ 941 ipc->shtx.flags = 0; 942 } 943 if (skb == NULL) 944 goto error; 945 946 /* 947 * Fill in the control structures 948 */ 949 skb->ip_summed = csummode; 950 skb->csum = 0; 951 skb_reserve(skb, hh_len); 952 *skb_tx(skb) = ipc->shtx; 953 954 /* 955 * Find where to start putting bytes. 956 */ 957 data = skb_put(skb, fraglen); 958 skb_set_network_header(skb, exthdrlen); 959 skb->transport_header = (skb->network_header + 960 fragheaderlen); 961 data += fragheaderlen; 962 963 if (fraggap) { 964 skb->csum = skb_copy_and_csum_bits( 965 skb_prev, maxfraglen, 966 data + transhdrlen, fraggap, 0); 967 skb_prev->csum = csum_sub(skb_prev->csum, 968 skb->csum); 969 data += fraggap; 970 pskb_trim_unique(skb_prev, maxfraglen); 971 } 972 973 copy = datalen - transhdrlen - fraggap; 974 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { 975 err = -EFAULT; 976 kfree_skb(skb); 977 goto error; 978 } 979 980 offset += copy; 981 length -= datalen - fraggap; 982 transhdrlen = 0; 983 exthdrlen = 0; 984 csummode = CHECKSUM_NONE; 985 986 /* 987 * Put the packet on the pending queue. 988 */ 989 __skb_queue_tail(&sk->sk_write_queue, skb); 990 continue; 991 } 992 993 if (copy > length) 994 copy = length; 995 996 if (!(rt->u.dst.dev->features&NETIF_F_SG)) { 997 unsigned int off; 998 999 off = skb->len; 1000 if (getfrag(from, skb_put(skb, copy), 1001 offset, copy, off, skb) < 0) { 1002 __skb_trim(skb, off); 1003 err = -EFAULT; 1004 goto error; 1005 } 1006 } else { 1007 int i = skb_shinfo(skb)->nr_frags; 1008 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; 1009 struct page *page = sk->sk_sndmsg_page; 1010 int off = sk->sk_sndmsg_off; 1011 unsigned int left; 1012 1013 if (page && (left = PAGE_SIZE - off) > 0) { 1014 if (copy >= left) 1015 copy = left; 1016 if (page != frag->page) { 1017 if (i == MAX_SKB_FRAGS) { 1018 err = -EMSGSIZE; 1019 goto error; 1020 } 1021 get_page(page); 1022 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); 1023 frag = &skb_shinfo(skb)->frags[i]; 1024 } 1025 } else if (i < MAX_SKB_FRAGS) { 1026 if (copy > PAGE_SIZE) 1027 copy = PAGE_SIZE; 1028 page = alloc_pages(sk->sk_allocation, 0); 1029 if (page == NULL) { 1030 err = -ENOMEM; 1031 goto error; 1032 } 1033 sk->sk_sndmsg_page = page; 1034 sk->sk_sndmsg_off = 0; 1035 1036 skb_fill_page_desc(skb, i, page, 0, 0); 1037 frag = &skb_shinfo(skb)->frags[i]; 1038 } else { 1039 err = -EMSGSIZE; 1040 goto error; 1041 } 1042 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { 1043 err = -EFAULT; 1044 goto error; 1045 } 1046 sk->sk_sndmsg_off += copy; 1047 frag->size += copy; 1048 skb->len += copy; 1049 skb->data_len += copy; 1050 skb->truesize += copy; 1051 atomic_add(copy, &sk->sk_wmem_alloc); 1052 } 1053 offset += copy; 1054 length -= copy; 1055 } 1056 1057 return 0; 1058 1059 error: 1060 inet->cork.length -= length; 1061 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1062 return err; 1063 } 1064 1065 ssize_t ip_append_page(struct sock *sk, struct page *page, 1066 int offset, size_t size, int flags) 1067 { 1068 struct inet_sock *inet = inet_sk(sk); 1069 struct sk_buff *skb; 1070 struct rtable *rt; 1071 struct ip_options *opt = NULL; 1072 int hh_len; 1073 int mtu; 1074 int len; 1075 int err; 1076 unsigned int maxfraglen, fragheaderlen, fraggap; 1077 1078 if (inet->hdrincl) 1079 return -EPERM; 1080 1081 if (flags&MSG_PROBE) 1082 return 0; 1083 1084 if (skb_queue_empty(&sk->sk_write_queue)) 1085 return -EINVAL; 1086 1087 rt = (struct rtable *)inet->cork.dst; 1088 if (inet->cork.flags & IPCORK_OPT) 1089 opt = inet->cork.opt; 1090 1091 if (!(rt->u.dst.dev->features&NETIF_F_SG)) 1092 return -EOPNOTSUPP; 1093 1094 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); 1095 mtu = inet->cork.fragsize; 1096 1097 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); 1098 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; 1099 1100 if (inet->cork.length + size > 0xFFFF - fragheaderlen) { 1101 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); 1102 return -EMSGSIZE; 1103 } 1104 1105 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) 1106 return -EINVAL; 1107 1108 inet->cork.length += size; 1109 if ((sk->sk_protocol == IPPROTO_UDP) && 1110 (rt->u.dst.dev->features & NETIF_F_UFO)) { 1111 skb_shinfo(skb)->gso_size = mtu - fragheaderlen; 1112 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1113 } 1114 1115 1116 while (size > 0) { 1117 int i; 1118 1119 if (skb_is_gso(skb)) 1120 len = size; 1121 else { 1122 1123 /* Check if the remaining data fits into current packet. */ 1124 len = mtu - skb->len; 1125 if (len < size) 1126 len = maxfraglen - skb->len; 1127 } 1128 if (len <= 0) { 1129 struct sk_buff *skb_prev; 1130 int alloclen; 1131 1132 skb_prev = skb; 1133 fraggap = skb_prev->len - maxfraglen; 1134 1135 alloclen = fragheaderlen + hh_len + fraggap + 15; 1136 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); 1137 if (unlikely(!skb)) { 1138 err = -ENOBUFS; 1139 goto error; 1140 } 1141 1142 /* 1143 * Fill in the control structures 1144 */ 1145 skb->ip_summed = CHECKSUM_NONE; 1146 skb->csum = 0; 1147 skb_reserve(skb, hh_len); 1148 1149 /* 1150 * Find where to start putting bytes. 1151 */ 1152 skb_put(skb, fragheaderlen + fraggap); 1153 skb_reset_network_header(skb); 1154 skb->transport_header = (skb->network_header + 1155 fragheaderlen); 1156 if (fraggap) { 1157 skb->csum = skb_copy_and_csum_bits(skb_prev, 1158 maxfraglen, 1159 skb_transport_header(skb), 1160 fraggap, 0); 1161 skb_prev->csum = csum_sub(skb_prev->csum, 1162 skb->csum); 1163 pskb_trim_unique(skb_prev, maxfraglen); 1164 } 1165 1166 /* 1167 * Put the packet on the pending queue. 1168 */ 1169 __skb_queue_tail(&sk->sk_write_queue, skb); 1170 continue; 1171 } 1172 1173 i = skb_shinfo(skb)->nr_frags; 1174 if (len > size) 1175 len = size; 1176 if (skb_can_coalesce(skb, i, page, offset)) { 1177 skb_shinfo(skb)->frags[i-1].size += len; 1178 } else if (i < MAX_SKB_FRAGS) { 1179 get_page(page); 1180 skb_fill_page_desc(skb, i, page, offset, len); 1181 } else { 1182 err = -EMSGSIZE; 1183 goto error; 1184 } 1185 1186 if (skb->ip_summed == CHECKSUM_NONE) { 1187 __wsum csum; 1188 csum = csum_page(page, offset, len); 1189 skb->csum = csum_block_add(skb->csum, csum, skb->len); 1190 } 1191 1192 skb->len += len; 1193 skb->data_len += len; 1194 skb->truesize += len; 1195 atomic_add(len, &sk->sk_wmem_alloc); 1196 offset += len; 1197 size -= len; 1198 } 1199 return 0; 1200 1201 error: 1202 inet->cork.length -= size; 1203 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); 1204 return err; 1205 } 1206 1207 static void ip_cork_release(struct inet_sock *inet) 1208 { 1209 inet->cork.flags &= ~IPCORK_OPT; 1210 kfree(inet->cork.opt); 1211 inet->cork.opt = NULL; 1212 dst_release(inet->cork.dst); 1213 inet->cork.dst = NULL; 1214 } 1215 1216 /* 1217 * Combined all pending IP fragments on the socket as one IP datagram 1218 * and push them out. 1219 */ 1220 int ip_push_pending_frames(struct sock *sk) 1221 { 1222 struct sk_buff *skb, *tmp_skb; 1223 struct sk_buff **tail_skb; 1224 struct inet_sock *inet = inet_sk(sk); 1225 struct net *net = sock_net(sk); 1226 struct ip_options *opt = NULL; 1227 struct rtable *rt = (struct rtable *)inet->cork.dst; 1228 struct iphdr *iph; 1229 __be16 df = 0; 1230 __u8 ttl; 1231 int err = 0; 1232 1233 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) 1234 goto out; 1235 tail_skb = &(skb_shinfo(skb)->frag_list); 1236 1237 /* move skb->data to ip header from ext header */ 1238 if (skb->data < skb_network_header(skb)) 1239 __skb_pull(skb, skb_network_offset(skb)); 1240 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { 1241 __skb_pull(tmp_skb, skb_network_header_len(skb)); 1242 *tail_skb = tmp_skb; 1243 tail_skb = &(tmp_skb->next); 1244 skb->len += tmp_skb->len; 1245 skb->data_len += tmp_skb->len; 1246 skb->truesize += tmp_skb->truesize; 1247 __sock_put(tmp_skb->sk); 1248 tmp_skb->destructor = NULL; 1249 tmp_skb->sk = NULL; 1250 } 1251 1252 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow 1253 * to fragment the frame generated here. No matter, what transforms 1254 * how transforms change size of the packet, it will come out. 1255 */ 1256 if (inet->pmtudisc < IP_PMTUDISC_DO) 1257 skb->local_df = 1; 1258 1259 /* DF bit is set when we want to see DF on outgoing frames. 1260 * If local_df is set too, we still allow to fragment this frame 1261 * locally. */ 1262 if (inet->pmtudisc >= IP_PMTUDISC_DO || 1263 (skb->len <= dst_mtu(&rt->u.dst) && 1264 ip_dont_fragment(sk, &rt->u.dst))) 1265 df = htons(IP_DF); 1266 1267 if (inet->cork.flags & IPCORK_OPT) 1268 opt = inet->cork.opt; 1269 1270 if (rt->rt_type == RTN_MULTICAST) 1271 ttl = inet->mc_ttl; 1272 else 1273 ttl = ip_select_ttl(inet, &rt->u.dst); 1274 1275 iph = (struct iphdr *)skb->data; 1276 iph->version = 4; 1277 iph->ihl = 5; 1278 if (opt) { 1279 iph->ihl += opt->optlen>>2; 1280 ip_options_build(skb, opt, inet->cork.addr, rt, 0); 1281 } 1282 iph->tos = inet->tos; 1283 iph->frag_off = df; 1284 ip_select_ident(iph, &rt->u.dst, sk); 1285 iph->ttl = ttl; 1286 iph->protocol = sk->sk_protocol; 1287 iph->saddr = rt->rt_src; 1288 iph->daddr = rt->rt_dst; 1289 1290 skb->priority = sk->sk_priority; 1291 skb->mark = sk->sk_mark; 1292 /* 1293 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec 1294 * on dst refcount 1295 */ 1296 inet->cork.dst = NULL; 1297 skb->dst = &rt->u.dst; 1298 1299 if (iph->protocol == IPPROTO_ICMP) 1300 icmp_out_count(net, ((struct icmphdr *) 1301 skb_transport_header(skb))->type); 1302 1303 /* Netfilter gets whole the not fragmented skb. */ 1304 err = ip_local_out(skb); 1305 if (err) { 1306 if (err > 0) 1307 err = inet->recverr ? net_xmit_errno(err) : 0; 1308 if (err) 1309 goto error; 1310 } 1311 1312 out: 1313 ip_cork_release(inet); 1314 return err; 1315 1316 error: 1317 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); 1318 goto out; 1319 } 1320 1321 /* 1322 * Throw away all pending data on the socket. 1323 */ 1324 void ip_flush_pending_frames(struct sock *sk) 1325 { 1326 struct sk_buff *skb; 1327 1328 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 1329 kfree_skb(skb); 1330 1331 ip_cork_release(inet_sk(sk)); 1332 } 1333 1334 1335 /* 1336 * Fetch data from kernel space and fill in checksum if needed. 1337 */ 1338 static int ip_reply_glue_bits(void *dptr, char *to, int offset, 1339 int len, int odd, struct sk_buff *skb) 1340 { 1341 __wsum csum; 1342 1343 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); 1344 skb->csum = csum_block_add(skb->csum, csum, odd); 1345 return 0; 1346 } 1347 1348 /* 1349 * Generic function to send a packet as reply to another packet. 1350 * Used to send TCP resets so far. ICMP should use this function too. 1351 * 1352 * Should run single threaded per socket because it uses the sock 1353 * structure to pass arguments. 1354 */ 1355 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 1356 unsigned int len) 1357 { 1358 struct inet_sock *inet = inet_sk(sk); 1359 struct { 1360 struct ip_options opt; 1361 char data[40]; 1362 } replyopts; 1363 struct ipcm_cookie ipc; 1364 __be32 daddr; 1365 struct rtable *rt = skb->rtable; 1366 1367 if (ip_options_echo(&replyopts.opt, skb)) 1368 return; 1369 1370 daddr = ipc.addr = rt->rt_src; 1371 ipc.opt = NULL; 1372 ipc.shtx.flags = 0; 1373 1374 if (replyopts.opt.optlen) { 1375 ipc.opt = &replyopts.opt; 1376 1377 if (ipc.opt->srr) 1378 daddr = replyopts.opt.faddr; 1379 } 1380 1381 { 1382 struct flowi fl = { .oif = arg->bound_dev_if, 1383 .nl_u = { .ip4_u = 1384 { .daddr = daddr, 1385 .saddr = rt->rt_spec_dst, 1386 .tos = RT_TOS(ip_hdr(skb)->tos) } }, 1387 /* Not quite clean, but right. */ 1388 .uli_u = { .ports = 1389 { .sport = tcp_hdr(skb)->dest, 1390 .dport = tcp_hdr(skb)->source } }, 1391 .proto = sk->sk_protocol, 1392 .flags = ip_reply_arg_flowi_flags(arg) }; 1393 security_skb_classify_flow(skb, &fl); 1394 if (ip_route_output_key(sock_net(sk), &rt, &fl)) 1395 return; 1396 } 1397 1398 /* And let IP do all the hard work. 1399 1400 This chunk is not reenterable, hence spinlock. 1401 Note that it uses the fact, that this function is called 1402 with locally disabled BH and that sk cannot be already spinlocked. 1403 */ 1404 bh_lock_sock(sk); 1405 inet->tos = ip_hdr(skb)->tos; 1406 sk->sk_priority = skb->priority; 1407 sk->sk_protocol = ip_hdr(skb)->protocol; 1408 sk->sk_bound_dev_if = arg->bound_dev_if; 1409 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, 1410 &ipc, &rt, MSG_DONTWAIT); 1411 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { 1412 if (arg->csumoffset >= 0) 1413 *((__sum16 *)skb_transport_header(skb) + 1414 arg->csumoffset) = csum_fold(csum_add(skb->csum, 1415 arg->csum)); 1416 skb->ip_summed = CHECKSUM_NONE; 1417 ip_push_pending_frames(sk); 1418 } 1419 1420 bh_unlock_sock(sk); 1421 1422 ip_rt_put(rt); 1423 } 1424 1425 void __init ip_init(void) 1426 { 1427 ip_rt_init(); 1428 inet_initpeers(); 1429 1430 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) 1431 igmp_mc_proc_init(); 1432 #endif 1433 } 1434 1435 EXPORT_SYMBOL(ip_generic_getfrag); 1436 EXPORT_SYMBOL(ip_queue_xmit); 1437 EXPORT_SYMBOL(ip_send_check); 1438