net: Handle encapsulated offloads before fragmentation or handing to lower dev
[linux-2.6/cjktty.git] / net / ipv4 / ip_output.c
blob3e98ed2bff55d7328aae7209ecbda4f78445c87a
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.
6 * The Internet Protocol (IP) output module.
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>
18 * See ip_input.c for original log
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.
45 #include <asm/uaccess.h>
46 #include <linux/module.h>
47 #include <linux/types.h>
48 #include <linux/kernel.h>
49 #include <linux/mm.h>
50 #include <linux/string.h>
51 #include <linux/errno.h>
52 #include <linux/highmem.h>
53 #include <linux/slab.h>
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>
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>
83 int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
84 EXPORT_SYMBOL(sysctl_ip_default_ttl);
86 /* Generate a checksum for an outgoing IP datagram. */
87 __inline__ void ip_send_check(struct iphdr *iph)
89 iph->check = 0;
90 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
92 EXPORT_SYMBOL(ip_send_check);
94 int __ip_local_out(struct sk_buff *skb)
96 struct iphdr *iph = ip_hdr(skb);
98 iph->tot_len = htons(skb->len);
99 ip_send_check(iph);
100 return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, skb, NULL,
101 skb_dst(skb)->dev, dst_output);
104 int ip_local_out(struct sk_buff *skb)
106 int err;
108 err = __ip_local_out(skb);
109 if (likely(err == 1))
110 err = dst_output(skb);
112 return err;
114 EXPORT_SYMBOL_GPL(ip_local_out);
116 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
118 int ttl = inet->uc_ttl;
120 if (ttl < 0)
121 ttl = ip4_dst_hoplimit(dst);
122 return ttl;
126 * Add an ip header to a skbuff and send it out.
129 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
130 __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
132 struct inet_sock *inet = inet_sk(sk);
133 struct rtable *rt = skb_rtable(skb);
134 struct iphdr *iph;
136 /* Build the IP header. */
137 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
138 skb_reset_network_header(skb);
139 iph = ip_hdr(skb);
140 iph->version = 4;
141 iph->ihl = 5;
142 iph->tos = inet->tos;
143 if (ip_dont_fragment(sk, &rt->dst))
144 iph->frag_off = htons(IP_DF);
145 else
146 iph->frag_off = 0;
147 iph->ttl = ip_select_ttl(inet, &rt->dst);
148 iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
149 iph->saddr = saddr;
150 iph->protocol = sk->sk_protocol;
151 ip_select_ident(iph, &rt->dst, sk);
153 if (opt && opt->opt.optlen) {
154 iph->ihl += opt->opt.optlen>>2;
155 ip_options_build(skb, &opt->opt, daddr, rt, 0);
158 skb->priority = sk->sk_priority;
159 skb->mark = sk->sk_mark;
161 /* Send it out. */
162 return ip_local_out(skb);
164 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
166 static inline int ip_finish_output2(struct sk_buff *skb)
168 struct dst_entry *dst = skb_dst(skb);
169 struct rtable *rt = (struct rtable *)dst;
170 struct net_device *dev = dst->dev;
171 unsigned int hh_len = LL_RESERVED_SPACE(dev);
172 struct neighbour *neigh;
173 u32 nexthop;
175 if (rt->rt_type == RTN_MULTICAST) {
176 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
177 } else if (rt->rt_type == RTN_BROADCAST)
178 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len);
180 /* Be paranoid, rather than too clever. */
181 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
182 struct sk_buff *skb2;
184 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
185 if (skb2 == NULL) {
186 kfree_skb(skb);
187 return -ENOMEM;
189 if (skb->sk)
190 skb_set_owner_w(skb2, skb->sk);
191 consume_skb(skb);
192 skb = skb2;
195 rcu_read_lock_bh();
196 nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr);
197 neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
198 if (unlikely(!neigh))
199 neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
200 if (!IS_ERR(neigh)) {
201 int res = dst_neigh_output(dst, neigh, skb);
203 rcu_read_unlock_bh();
204 return res;
206 rcu_read_unlock_bh();
208 net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
209 __func__);
210 kfree_skb(skb);
211 return -EINVAL;
214 static inline int ip_skb_dst_mtu(struct sk_buff *skb)
216 struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
218 return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
219 skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
222 static int ip_finish_output(struct sk_buff *skb)
224 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
225 /* Policy lookup after SNAT yielded a new policy */
226 if (skb_dst(skb)->xfrm != NULL) {
227 IPCB(skb)->flags |= IPSKB_REROUTED;
228 return dst_output(skb);
230 #endif
231 if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb))
232 return ip_fragment(skb, ip_finish_output2);
233 else
234 return ip_finish_output2(skb);
237 int ip_mc_output(struct sk_buff *skb)
239 struct sock *sk = skb->sk;
240 struct rtable *rt = skb_rtable(skb);
241 struct net_device *dev = rt->dst.dev;
244 * If the indicated interface is up and running, send the packet.
246 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
248 skb->dev = dev;
249 skb->protocol = htons(ETH_P_IP);
252 * Multicasts are looped back for other local users
255 if (rt->rt_flags&RTCF_MULTICAST) {
256 if (sk_mc_loop(sk)
257 #ifdef CONFIG_IP_MROUTE
258 /* Small optimization: do not loopback not local frames,
259 which returned after forwarding; they will be dropped
260 by ip_mr_input in any case.
261 Note, that local frames are looped back to be delivered
262 to local recipients.
264 This check is duplicated in ip_mr_input at the moment.
267 ((rt->rt_flags & RTCF_LOCAL) ||
268 !(IPCB(skb)->flags & IPSKB_FORWARDED))
269 #endif
271 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
272 if (newskb)
273 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
274 newskb, NULL, newskb->dev,
275 dev_loopback_xmit);
278 /* Multicasts with ttl 0 must not go beyond the host */
280 if (ip_hdr(skb)->ttl == 0) {
281 kfree_skb(skb);
282 return 0;
286 if (rt->rt_flags&RTCF_BROADCAST) {
287 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
288 if (newskb)
289 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb,
290 NULL, newskb->dev, dev_loopback_xmit);
293 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL,
294 skb->dev, ip_finish_output,
295 !(IPCB(skb)->flags & IPSKB_REROUTED));
298 int ip_output(struct sk_buff *skb)
300 struct net_device *dev = skb_dst(skb)->dev;
302 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
304 skb->dev = dev;
305 skb->protocol = htons(ETH_P_IP);
307 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev,
308 ip_finish_output,
309 !(IPCB(skb)->flags & IPSKB_REROUTED));
313 * copy saddr and daddr, possibly using 64bit load/stores
314 * Equivalent to :
315 * iph->saddr = fl4->saddr;
316 * iph->daddr = fl4->daddr;
318 static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
320 BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
321 offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
322 memcpy(&iph->saddr, &fl4->saddr,
323 sizeof(fl4->saddr) + sizeof(fl4->daddr));
326 int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
328 struct sock *sk = skb->sk;
329 struct inet_sock *inet = inet_sk(sk);
330 struct ip_options_rcu *inet_opt;
331 struct flowi4 *fl4;
332 struct rtable *rt;
333 struct iphdr *iph;
334 int res;
336 /* Skip all of this if the packet is already routed,
337 * f.e. by something like SCTP.
339 rcu_read_lock();
340 inet_opt = rcu_dereference(inet->inet_opt);
341 fl4 = &fl->u.ip4;
342 rt = skb_rtable(skb);
343 if (rt != NULL)
344 goto packet_routed;
346 /* Make sure we can route this packet. */
347 rt = (struct rtable *)__sk_dst_check(sk, 0);
348 if (rt == NULL) {
349 __be32 daddr;
351 /* Use correct destination address if we have options. */
352 daddr = inet->inet_daddr;
353 if (inet_opt && inet_opt->opt.srr)
354 daddr = inet_opt->opt.faddr;
356 /* If this fails, retransmit mechanism of transport layer will
357 * keep trying until route appears or the connection times
358 * itself out.
360 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
361 daddr, inet->inet_saddr,
362 inet->inet_dport,
363 inet->inet_sport,
364 sk->sk_protocol,
365 RT_CONN_FLAGS(sk),
366 sk->sk_bound_dev_if);
367 if (IS_ERR(rt))
368 goto no_route;
369 sk_setup_caps(sk, &rt->dst);
371 skb_dst_set_noref(skb, &rt->dst);
373 packet_routed:
374 if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
375 goto no_route;
377 /* OK, we know where to send it, allocate and build IP header. */
378 skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
379 skb_reset_network_header(skb);
380 iph = ip_hdr(skb);
381 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
382 if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df)
383 iph->frag_off = htons(IP_DF);
384 else
385 iph->frag_off = 0;
386 iph->ttl = ip_select_ttl(inet, &rt->dst);
387 iph->protocol = sk->sk_protocol;
388 ip_copy_addrs(iph, fl4);
390 /* Transport layer set skb->h.foo itself. */
392 if (inet_opt && inet_opt->opt.optlen) {
393 iph->ihl += inet_opt->opt.optlen >> 2;
394 ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
397 ip_select_ident_more(iph, &rt->dst, sk,
398 (skb_shinfo(skb)->gso_segs ?: 1) - 1);
400 skb->priority = sk->sk_priority;
401 skb->mark = sk->sk_mark;
403 res = ip_local_out(skb);
404 rcu_read_unlock();
405 return res;
407 no_route:
408 rcu_read_unlock();
409 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
410 kfree_skb(skb);
411 return -EHOSTUNREACH;
413 EXPORT_SYMBOL(ip_queue_xmit);
416 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
418 to->pkt_type = from->pkt_type;
419 to->priority = from->priority;
420 to->protocol = from->protocol;
421 skb_dst_drop(to);
422 skb_dst_copy(to, from);
423 to->dev = from->dev;
424 to->mark = from->mark;
426 /* Copy the flags to each fragment. */
427 IPCB(to)->flags = IPCB(from)->flags;
429 #ifdef CONFIG_NET_SCHED
430 to->tc_index = from->tc_index;
431 #endif
432 nf_copy(to, from);
433 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
434 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
435 to->nf_trace = from->nf_trace;
436 #endif
437 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
438 to->ipvs_property = from->ipvs_property;
439 #endif
440 skb_copy_secmark(to, from);
444 * This IP datagram is too large to be sent in one piece. Break it up into
445 * smaller pieces (each of size equal to IP header plus
446 * a block of the data of the original IP data part) that will yet fit in a
447 * single device frame, and queue such a frame for sending.
450 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
452 struct iphdr *iph;
453 int ptr;
454 struct net_device *dev;
455 struct sk_buff *skb2;
456 unsigned int mtu, hlen, left, len, ll_rs;
457 int offset;
458 __be16 not_last_frag;
459 struct rtable *rt = skb_rtable(skb);
460 int err = 0;
462 dev = rt->dst.dev;
465 * Point into the IP datagram header.
468 iph = ip_hdr(skb);
470 if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->local_df) ||
471 (IPCB(skb)->frag_max_size &&
472 IPCB(skb)->frag_max_size > dst_mtu(&rt->dst)))) {
473 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
474 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
475 htonl(ip_skb_dst_mtu(skb)));
476 kfree_skb(skb);
477 return -EMSGSIZE;
481 * Setup starting values.
484 hlen = iph->ihl * 4;
485 mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */
486 #ifdef CONFIG_BRIDGE_NETFILTER
487 if (skb->nf_bridge)
488 mtu -= nf_bridge_mtu_reduction(skb);
489 #endif
490 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
492 /* When frag_list is given, use it. First, check its validity:
493 * some transformers could create wrong frag_list or break existing
494 * one, it is not prohibited. In this case fall back to copying.
496 * LATER: this step can be merged to real generation of fragments,
497 * we can switch to copy when see the first bad fragment.
499 if (skb_has_frag_list(skb)) {
500 struct sk_buff *frag, *frag2;
501 int first_len = skb_pagelen(skb);
503 if (first_len - hlen > mtu ||
504 ((first_len - hlen) & 7) ||
505 ip_is_fragment(iph) ||
506 skb_cloned(skb))
507 goto slow_path;
509 skb_walk_frags(skb, frag) {
510 /* Correct geometry. */
511 if (frag->len > mtu ||
512 ((frag->len & 7) && frag->next) ||
513 skb_headroom(frag) < hlen)
514 goto slow_path_clean;
516 /* Partially cloned skb? */
517 if (skb_shared(frag))
518 goto slow_path_clean;
520 BUG_ON(frag->sk);
521 if (skb->sk) {
522 frag->sk = skb->sk;
523 frag->destructor = sock_wfree;
525 skb->truesize -= frag->truesize;
528 /* Everything is OK. Generate! */
530 err = 0;
531 offset = 0;
532 frag = skb_shinfo(skb)->frag_list;
533 skb_frag_list_init(skb);
534 skb->data_len = first_len - skb_headlen(skb);
535 skb->len = first_len;
536 iph->tot_len = htons(first_len);
537 iph->frag_off = htons(IP_MF);
538 ip_send_check(iph);
540 for (;;) {
541 /* Prepare header of the next frame,
542 * before previous one went down. */
543 if (frag) {
544 frag->ip_summed = CHECKSUM_NONE;
545 skb_reset_transport_header(frag);
546 __skb_push(frag, hlen);
547 skb_reset_network_header(frag);
548 memcpy(skb_network_header(frag), iph, hlen);
549 iph = ip_hdr(frag);
550 iph->tot_len = htons(frag->len);
551 ip_copy_metadata(frag, skb);
552 if (offset == 0)
553 ip_options_fragment(frag);
554 offset += skb->len - hlen;
555 iph->frag_off = htons(offset>>3);
556 if (frag->next != NULL)
557 iph->frag_off |= htons(IP_MF);
558 /* Ready, complete checksum */
559 ip_send_check(iph);
562 err = output(skb);
564 if (!err)
565 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
566 if (err || !frag)
567 break;
569 skb = frag;
570 frag = skb->next;
571 skb->next = NULL;
574 if (err == 0) {
575 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
576 return 0;
579 while (frag) {
580 skb = frag->next;
581 kfree_skb(frag);
582 frag = skb;
584 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
585 return err;
587 slow_path_clean:
588 skb_walk_frags(skb, frag2) {
589 if (frag2 == frag)
590 break;
591 frag2->sk = NULL;
592 frag2->destructor = NULL;
593 skb->truesize += frag2->truesize;
597 slow_path:
598 /* for offloaded checksums cleanup checksum before fragmentation */
599 if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb))
600 goto fail;
602 left = skb->len - hlen; /* Space per frame */
603 ptr = hlen; /* Where to start from */
605 /* for bridged IP traffic encapsulated inside f.e. a vlan header,
606 * we need to make room for the encapsulating header
608 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb));
611 * Fragment the datagram.
614 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
615 not_last_frag = iph->frag_off & htons(IP_MF);
618 * Keep copying data until we run out.
621 while (left > 0) {
622 len = left;
623 /* IF: it doesn't fit, use 'mtu' - the data space left */
624 if (len > mtu)
625 len = mtu;
626 /* IF: we are not sending up to and including the packet end
627 then align the next start on an eight byte boundary */
628 if (len < left) {
629 len &= ~7;
632 * Allocate buffer.
635 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) {
636 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n");
637 err = -ENOMEM;
638 goto fail;
642 * Set up data on packet
645 ip_copy_metadata(skb2, skb);
646 skb_reserve(skb2, ll_rs);
647 skb_put(skb2, len + hlen);
648 skb_reset_network_header(skb2);
649 skb2->transport_header = skb2->network_header + hlen;
652 * Charge the memory for the fragment to any owner
653 * it might possess
656 if (skb->sk)
657 skb_set_owner_w(skb2, skb->sk);
660 * Copy the packet header into the new buffer.
663 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
666 * Copy a block of the IP datagram.
668 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
669 BUG();
670 left -= len;
673 * Fill in the new header fields.
675 iph = ip_hdr(skb2);
676 iph->frag_off = htons((offset >> 3));
678 /* ANK: dirty, but effective trick. Upgrade options only if
679 * the segment to be fragmented was THE FIRST (otherwise,
680 * options are already fixed) and make it ONCE
681 * on the initial skb, so that all the following fragments
682 * will inherit fixed options.
684 if (offset == 0)
685 ip_options_fragment(skb);
688 * Added AC : If we are fragmenting a fragment that's not the
689 * last fragment then keep MF on each bit
691 if (left > 0 || not_last_frag)
692 iph->frag_off |= htons(IP_MF);
693 ptr += len;
694 offset += len;
697 * Put this fragment into the sending queue.
699 iph->tot_len = htons(len + hlen);
701 ip_send_check(iph);
703 err = output(skb2);
704 if (err)
705 goto fail;
707 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
709 consume_skb(skb);
710 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
711 return err;
713 fail:
714 kfree_skb(skb);
715 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
716 return err;
718 EXPORT_SYMBOL(ip_fragment);
721 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
723 struct iovec *iov = from;
725 if (skb->ip_summed == CHECKSUM_PARTIAL) {
726 if (memcpy_fromiovecend(to, iov, offset, len) < 0)
727 return -EFAULT;
728 } else {
729 __wsum csum = 0;
730 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
731 return -EFAULT;
732 skb->csum = csum_block_add(skb->csum, csum, odd);
734 return 0;
736 EXPORT_SYMBOL(ip_generic_getfrag);
738 static inline __wsum
739 csum_page(struct page *page, int offset, int copy)
741 char *kaddr;
742 __wsum csum;
743 kaddr = kmap(page);
744 csum = csum_partial(kaddr + offset, copy, 0);
745 kunmap(page);
746 return csum;
749 static inline int ip_ufo_append_data(struct sock *sk,
750 struct sk_buff_head *queue,
751 int getfrag(void *from, char *to, int offset, int len,
752 int odd, struct sk_buff *skb),
753 void *from, int length, int hh_len, int fragheaderlen,
754 int transhdrlen, int maxfraglen, unsigned int flags)
756 struct sk_buff *skb;
757 int err;
759 /* There is support for UDP fragmentation offload by network
760 * device, so create one single skb packet containing complete
761 * udp datagram
763 if ((skb = skb_peek_tail(queue)) == NULL) {
764 skb = sock_alloc_send_skb(sk,
765 hh_len + fragheaderlen + transhdrlen + 20,
766 (flags & MSG_DONTWAIT), &err);
768 if (skb == NULL)
769 return err;
771 /* reserve space for Hardware header */
772 skb_reserve(skb, hh_len);
774 /* create space for UDP/IP header */
775 skb_put(skb, fragheaderlen + transhdrlen);
777 /* initialize network header pointer */
778 skb_reset_network_header(skb);
780 /* initialize protocol header pointer */
781 skb->transport_header = skb->network_header + fragheaderlen;
783 skb->ip_summed = CHECKSUM_PARTIAL;
784 skb->csum = 0;
786 /* specify the length of each IP datagram fragment */
787 skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen;
788 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
789 __skb_queue_tail(queue, skb);
792 return skb_append_datato_frags(sk, skb, getfrag, from,
793 (length - transhdrlen));
796 static int __ip_append_data(struct sock *sk,
797 struct flowi4 *fl4,
798 struct sk_buff_head *queue,
799 struct inet_cork *cork,
800 struct page_frag *pfrag,
801 int getfrag(void *from, char *to, int offset,
802 int len, int odd, struct sk_buff *skb),
803 void *from, int length, int transhdrlen,
804 unsigned int flags)
806 struct inet_sock *inet = inet_sk(sk);
807 struct sk_buff *skb;
809 struct ip_options *opt = cork->opt;
810 int hh_len;
811 int exthdrlen;
812 int mtu;
813 int copy;
814 int err;
815 int offset = 0;
816 unsigned int maxfraglen, fragheaderlen;
817 int csummode = CHECKSUM_NONE;
818 struct rtable *rt = (struct rtable *)cork->dst;
820 skb = skb_peek_tail(queue);
822 exthdrlen = !skb ? rt->dst.header_len : 0;
823 mtu = cork->fragsize;
825 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
827 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
828 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
830 if (cork->length + length > 0xFFFF - fragheaderlen) {
831 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
832 mtu-exthdrlen);
833 return -EMSGSIZE;
837 * transhdrlen > 0 means that this is the first fragment and we wish
838 * it won't be fragmented in the future.
840 if (transhdrlen &&
841 length + fragheaderlen <= mtu &&
842 rt->dst.dev->features & NETIF_F_V4_CSUM &&
843 !exthdrlen)
844 csummode = CHECKSUM_PARTIAL;
846 cork->length += length;
847 if (((length > mtu) || (skb && skb_is_gso(skb))) &&
848 (sk->sk_protocol == IPPROTO_UDP) &&
849 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) {
850 err = ip_ufo_append_data(sk, queue, getfrag, from, length,
851 hh_len, fragheaderlen, transhdrlen,
852 maxfraglen, flags);
853 if (err)
854 goto error;
855 return 0;
858 /* So, what's going on in the loop below?
860 * We use calculated fragment length to generate chained skb,
861 * each of segments is IP fragment ready for sending to network after
862 * adding appropriate IP header.
865 if (!skb)
866 goto alloc_new_skb;
868 while (length > 0) {
869 /* Check if the remaining data fits into current packet. */
870 copy = mtu - skb->len;
871 if (copy < length)
872 copy = maxfraglen - skb->len;
873 if (copy <= 0) {
874 char *data;
875 unsigned int datalen;
876 unsigned int fraglen;
877 unsigned int fraggap;
878 unsigned int alloclen;
879 struct sk_buff *skb_prev;
880 alloc_new_skb:
881 skb_prev = skb;
882 if (skb_prev)
883 fraggap = skb_prev->len - maxfraglen;
884 else
885 fraggap = 0;
888 * If remaining data exceeds the mtu,
889 * we know we need more fragment(s).
891 datalen = length + fraggap;
892 if (datalen > mtu - fragheaderlen)
893 datalen = maxfraglen - fragheaderlen;
894 fraglen = datalen + fragheaderlen;
896 if ((flags & MSG_MORE) &&
897 !(rt->dst.dev->features&NETIF_F_SG))
898 alloclen = mtu;
899 else
900 alloclen = fraglen;
902 alloclen += exthdrlen;
904 /* The last fragment gets additional space at tail.
905 * Note, with MSG_MORE we overallocate on fragments,
906 * because we have no idea what fragment will be
907 * the last.
909 if (datalen == length + fraggap)
910 alloclen += rt->dst.trailer_len;
912 if (transhdrlen) {
913 skb = sock_alloc_send_skb(sk,
914 alloclen + hh_len + 15,
915 (flags & MSG_DONTWAIT), &err);
916 } else {
917 skb = NULL;
918 if (atomic_read(&sk->sk_wmem_alloc) <=
919 2 * sk->sk_sndbuf)
920 skb = sock_wmalloc(sk,
921 alloclen + hh_len + 15, 1,
922 sk->sk_allocation);
923 if (unlikely(skb == NULL))
924 err = -ENOBUFS;
925 else
926 /* only the initial fragment is
927 time stamped */
928 cork->tx_flags = 0;
930 if (skb == NULL)
931 goto error;
934 * Fill in the control structures
936 skb->ip_summed = csummode;
937 skb->csum = 0;
938 skb_reserve(skb, hh_len);
939 skb_shinfo(skb)->tx_flags = cork->tx_flags;
942 * Find where to start putting bytes.
944 data = skb_put(skb, fraglen + exthdrlen);
945 skb_set_network_header(skb, exthdrlen);
946 skb->transport_header = (skb->network_header +
947 fragheaderlen);
948 data += fragheaderlen + exthdrlen;
950 if (fraggap) {
951 skb->csum = skb_copy_and_csum_bits(
952 skb_prev, maxfraglen,
953 data + transhdrlen, fraggap, 0);
954 skb_prev->csum = csum_sub(skb_prev->csum,
955 skb->csum);
956 data += fraggap;
957 pskb_trim_unique(skb_prev, maxfraglen);
960 copy = datalen - transhdrlen - fraggap;
961 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
962 err = -EFAULT;
963 kfree_skb(skb);
964 goto error;
967 offset += copy;
968 length -= datalen - fraggap;
969 transhdrlen = 0;
970 exthdrlen = 0;
971 csummode = CHECKSUM_NONE;
974 * Put the packet on the pending queue.
976 __skb_queue_tail(queue, skb);
977 continue;
980 if (copy > length)
981 copy = length;
983 if (!(rt->dst.dev->features&NETIF_F_SG)) {
984 unsigned int off;
986 off = skb->len;
987 if (getfrag(from, skb_put(skb, copy),
988 offset, copy, off, skb) < 0) {
989 __skb_trim(skb, off);
990 err = -EFAULT;
991 goto error;
993 } else {
994 int i = skb_shinfo(skb)->nr_frags;
996 err = -ENOMEM;
997 if (!sk_page_frag_refill(sk, pfrag))
998 goto error;
1000 if (!skb_can_coalesce(skb, i, pfrag->page,
1001 pfrag->offset)) {
1002 err = -EMSGSIZE;
1003 if (i == MAX_SKB_FRAGS)
1004 goto error;
1006 __skb_fill_page_desc(skb, i, pfrag->page,
1007 pfrag->offset, 0);
1008 skb_shinfo(skb)->nr_frags = ++i;
1009 get_page(pfrag->page);
1011 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1012 if (getfrag(from,
1013 page_address(pfrag->page) + pfrag->offset,
1014 offset, copy, skb->len, skb) < 0)
1015 goto error_efault;
1017 pfrag->offset += copy;
1018 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1019 skb->len += copy;
1020 skb->data_len += copy;
1021 skb->truesize += copy;
1022 atomic_add(copy, &sk->sk_wmem_alloc);
1024 offset += copy;
1025 length -= copy;
1028 return 0;
1030 error_efault:
1031 err = -EFAULT;
1032 error:
1033 cork->length -= length;
1034 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1035 return err;
1038 static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1039 struct ipcm_cookie *ipc, struct rtable **rtp)
1041 struct inet_sock *inet = inet_sk(sk);
1042 struct ip_options_rcu *opt;
1043 struct rtable *rt;
1046 * setup for corking.
1048 opt = ipc->opt;
1049 if (opt) {
1050 if (cork->opt == NULL) {
1051 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1052 sk->sk_allocation);
1053 if (unlikely(cork->opt == NULL))
1054 return -ENOBUFS;
1056 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1057 cork->flags |= IPCORK_OPT;
1058 cork->addr = ipc->addr;
1060 rt = *rtp;
1061 if (unlikely(!rt))
1062 return -EFAULT;
1064 * We steal reference to this route, caller should not release it
1066 *rtp = NULL;
1067 cork->fragsize = inet->pmtudisc == IP_PMTUDISC_PROBE ?
1068 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1069 cork->dst = &rt->dst;
1070 cork->length = 0;
1071 cork->tx_flags = ipc->tx_flags;
1073 return 0;
1077 * ip_append_data() and ip_append_page() can make one large IP datagram
1078 * from many pieces of data. Each pieces will be holded on the socket
1079 * until ip_push_pending_frames() is called. Each piece can be a page
1080 * or non-page data.
1082 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1083 * this interface potentially.
1085 * LATER: length must be adjusted by pad at tail, when it is required.
1087 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1088 int getfrag(void *from, char *to, int offset, int len,
1089 int odd, struct sk_buff *skb),
1090 void *from, int length, int transhdrlen,
1091 struct ipcm_cookie *ipc, struct rtable **rtp,
1092 unsigned int flags)
1094 struct inet_sock *inet = inet_sk(sk);
1095 int err;
1097 if (flags&MSG_PROBE)
1098 return 0;
1100 if (skb_queue_empty(&sk->sk_write_queue)) {
1101 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1102 if (err)
1103 return err;
1104 } else {
1105 transhdrlen = 0;
1108 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
1109 sk_page_frag(sk), getfrag,
1110 from, length, transhdrlen, flags);
1113 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1114 int offset, size_t size, int flags)
1116 struct inet_sock *inet = inet_sk(sk);
1117 struct sk_buff *skb;
1118 struct rtable *rt;
1119 struct ip_options *opt = NULL;
1120 struct inet_cork *cork;
1121 int hh_len;
1122 int mtu;
1123 int len;
1124 int err;
1125 unsigned int maxfraglen, fragheaderlen, fraggap;
1127 if (inet->hdrincl)
1128 return -EPERM;
1130 if (flags&MSG_PROBE)
1131 return 0;
1133 if (skb_queue_empty(&sk->sk_write_queue))
1134 return -EINVAL;
1136 cork = &inet->cork.base;
1137 rt = (struct rtable *)cork->dst;
1138 if (cork->flags & IPCORK_OPT)
1139 opt = cork->opt;
1141 if (!(rt->dst.dev->features&NETIF_F_SG))
1142 return -EOPNOTSUPP;
1144 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1145 mtu = cork->fragsize;
1147 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1148 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1150 if (cork->length + size > 0xFFFF - fragheaderlen) {
1151 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, mtu);
1152 return -EMSGSIZE;
1155 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1156 return -EINVAL;
1158 cork->length += size;
1159 if ((size + skb->len > mtu) &&
1160 (sk->sk_protocol == IPPROTO_UDP) &&
1161 (rt->dst.dev->features & NETIF_F_UFO)) {
1162 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1163 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1167 while (size > 0) {
1168 int i;
1170 if (skb_is_gso(skb))
1171 len = size;
1172 else {
1174 /* Check if the remaining data fits into current packet. */
1175 len = mtu - skb->len;
1176 if (len < size)
1177 len = maxfraglen - skb->len;
1179 if (len <= 0) {
1180 struct sk_buff *skb_prev;
1181 int alloclen;
1183 skb_prev = skb;
1184 fraggap = skb_prev->len - maxfraglen;
1186 alloclen = fragheaderlen + hh_len + fraggap + 15;
1187 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1188 if (unlikely(!skb)) {
1189 err = -ENOBUFS;
1190 goto error;
1194 * Fill in the control structures
1196 skb->ip_summed = CHECKSUM_NONE;
1197 skb->csum = 0;
1198 skb_reserve(skb, hh_len);
1201 * Find where to start putting bytes.
1203 skb_put(skb, fragheaderlen + fraggap);
1204 skb_reset_network_header(skb);
1205 skb->transport_header = (skb->network_header +
1206 fragheaderlen);
1207 if (fraggap) {
1208 skb->csum = skb_copy_and_csum_bits(skb_prev,
1209 maxfraglen,
1210 skb_transport_header(skb),
1211 fraggap, 0);
1212 skb_prev->csum = csum_sub(skb_prev->csum,
1213 skb->csum);
1214 pskb_trim_unique(skb_prev, maxfraglen);
1218 * Put the packet on the pending queue.
1220 __skb_queue_tail(&sk->sk_write_queue, skb);
1221 continue;
1224 i = skb_shinfo(skb)->nr_frags;
1225 if (len > size)
1226 len = size;
1227 if (skb_can_coalesce(skb, i, page, offset)) {
1228 skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
1229 } else if (i < MAX_SKB_FRAGS) {
1230 get_page(page);
1231 skb_fill_page_desc(skb, i, page, offset, len);
1232 } else {
1233 err = -EMSGSIZE;
1234 goto error;
1237 if (skb->ip_summed == CHECKSUM_NONE) {
1238 __wsum csum;
1239 csum = csum_page(page, offset, len);
1240 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1243 skb->len += len;
1244 skb->data_len += len;
1245 skb->truesize += len;
1246 atomic_add(len, &sk->sk_wmem_alloc);
1247 offset += len;
1248 size -= len;
1250 return 0;
1252 error:
1253 cork->length -= size;
1254 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1255 return err;
1258 static void ip_cork_release(struct inet_cork *cork)
1260 cork->flags &= ~IPCORK_OPT;
1261 kfree(cork->opt);
1262 cork->opt = NULL;
1263 dst_release(cork->dst);
1264 cork->dst = NULL;
1268 * Combined all pending IP fragments on the socket as one IP datagram
1269 * and push them out.
1271 struct sk_buff *__ip_make_skb(struct sock *sk,
1272 struct flowi4 *fl4,
1273 struct sk_buff_head *queue,
1274 struct inet_cork *cork)
1276 struct sk_buff *skb, *tmp_skb;
1277 struct sk_buff **tail_skb;
1278 struct inet_sock *inet = inet_sk(sk);
1279 struct net *net = sock_net(sk);
1280 struct ip_options *opt = NULL;
1281 struct rtable *rt = (struct rtable *)cork->dst;
1282 struct iphdr *iph;
1283 __be16 df = 0;
1284 __u8 ttl;
1286 if ((skb = __skb_dequeue(queue)) == NULL)
1287 goto out;
1288 tail_skb = &(skb_shinfo(skb)->frag_list);
1290 /* move skb->data to ip header from ext header */
1291 if (skb->data < skb_network_header(skb))
1292 __skb_pull(skb, skb_network_offset(skb));
1293 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1294 __skb_pull(tmp_skb, skb_network_header_len(skb));
1295 *tail_skb = tmp_skb;
1296 tail_skb = &(tmp_skb->next);
1297 skb->len += tmp_skb->len;
1298 skb->data_len += tmp_skb->len;
1299 skb->truesize += tmp_skb->truesize;
1300 tmp_skb->destructor = NULL;
1301 tmp_skb->sk = NULL;
1304 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1305 * to fragment the frame generated here. No matter, what transforms
1306 * how transforms change size of the packet, it will come out.
1308 if (inet->pmtudisc < IP_PMTUDISC_DO)
1309 skb->local_df = 1;
1311 /* DF bit is set when we want to see DF on outgoing frames.
1312 * If local_df is set too, we still allow to fragment this frame
1313 * locally. */
1314 if (inet->pmtudisc >= IP_PMTUDISC_DO ||
1315 (skb->len <= dst_mtu(&rt->dst) &&
1316 ip_dont_fragment(sk, &rt->dst)))
1317 df = htons(IP_DF);
1319 if (cork->flags & IPCORK_OPT)
1320 opt = cork->opt;
1322 if (rt->rt_type == RTN_MULTICAST)
1323 ttl = inet->mc_ttl;
1324 else
1325 ttl = ip_select_ttl(inet, &rt->dst);
1327 iph = (struct iphdr *)skb->data;
1328 iph->version = 4;
1329 iph->ihl = 5;
1330 iph->tos = inet->tos;
1331 iph->frag_off = df;
1332 iph->ttl = ttl;
1333 iph->protocol = sk->sk_protocol;
1334 ip_copy_addrs(iph, fl4);
1335 ip_select_ident(iph, &rt->dst, sk);
1337 if (opt) {
1338 iph->ihl += opt->optlen>>2;
1339 ip_options_build(skb, opt, cork->addr, rt, 0);
1342 skb->priority = sk->sk_priority;
1343 skb->mark = sk->sk_mark;
1345 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1346 * on dst refcount
1348 cork->dst = NULL;
1349 skb_dst_set(skb, &rt->dst);
1351 if (iph->protocol == IPPROTO_ICMP)
1352 icmp_out_count(net, ((struct icmphdr *)
1353 skb_transport_header(skb))->type);
1355 ip_cork_release(cork);
1356 out:
1357 return skb;
1360 int ip_send_skb(struct net *net, struct sk_buff *skb)
1362 int err;
1364 err = ip_local_out(skb);
1365 if (err) {
1366 if (err > 0)
1367 err = net_xmit_errno(err);
1368 if (err)
1369 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1372 return err;
1375 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
1377 struct sk_buff *skb;
1379 skb = ip_finish_skb(sk, fl4);
1380 if (!skb)
1381 return 0;
1383 /* Netfilter gets whole the not fragmented skb. */
1384 return ip_send_skb(sock_net(sk), skb);
1388 * Throw away all pending data on the socket.
1390 static void __ip_flush_pending_frames(struct sock *sk,
1391 struct sk_buff_head *queue,
1392 struct inet_cork *cork)
1394 struct sk_buff *skb;
1396 while ((skb = __skb_dequeue_tail(queue)) != NULL)
1397 kfree_skb(skb);
1399 ip_cork_release(cork);
1402 void ip_flush_pending_frames(struct sock *sk)
1404 __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1407 struct sk_buff *ip_make_skb(struct sock *sk,
1408 struct flowi4 *fl4,
1409 int getfrag(void *from, char *to, int offset,
1410 int len, int odd, struct sk_buff *skb),
1411 void *from, int length, int transhdrlen,
1412 struct ipcm_cookie *ipc, struct rtable **rtp,
1413 unsigned int flags)
1415 struct inet_cork cork;
1416 struct sk_buff_head queue;
1417 int err;
1419 if (flags & MSG_PROBE)
1420 return NULL;
1422 __skb_queue_head_init(&queue);
1424 cork.flags = 0;
1425 cork.addr = 0;
1426 cork.opt = NULL;
1427 err = ip_setup_cork(sk, &cork, ipc, rtp);
1428 if (err)
1429 return ERR_PTR(err);
1431 err = __ip_append_data(sk, fl4, &queue, &cork,
1432 &current->task_frag, getfrag,
1433 from, length, transhdrlen, flags);
1434 if (err) {
1435 __ip_flush_pending_frames(sk, &queue, &cork);
1436 return ERR_PTR(err);
1439 return __ip_make_skb(sk, fl4, &queue, &cork);
1443 * Fetch data from kernel space and fill in checksum if needed.
1445 static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1446 int len, int odd, struct sk_buff *skb)
1448 __wsum csum;
1450 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1451 skb->csum = csum_block_add(skb->csum, csum, odd);
1452 return 0;
1456 * Generic function to send a packet as reply to another packet.
1457 * Used to send some TCP resets/acks so far.
1459 * Use a fake percpu inet socket to avoid false sharing and contention.
1461 static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
1462 .sk = {
1463 .__sk_common = {
1464 .skc_refcnt = ATOMIC_INIT(1),
1466 .sk_wmem_alloc = ATOMIC_INIT(1),
1467 .sk_allocation = GFP_ATOMIC,
1468 .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE),
1470 .pmtudisc = IP_PMTUDISC_WANT,
1471 .uc_ttl = -1,
1474 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
1475 __be32 saddr, const struct ip_reply_arg *arg,
1476 unsigned int len)
1478 struct ip_options_data replyopts;
1479 struct ipcm_cookie ipc;
1480 struct flowi4 fl4;
1481 struct rtable *rt = skb_rtable(skb);
1482 struct sk_buff *nskb;
1483 struct sock *sk;
1484 struct inet_sock *inet;
1486 if (ip_options_echo(&replyopts.opt.opt, skb))
1487 return;
1489 ipc.addr = daddr;
1490 ipc.opt = NULL;
1491 ipc.tx_flags = 0;
1493 if (replyopts.opt.opt.optlen) {
1494 ipc.opt = &replyopts.opt;
1496 if (replyopts.opt.opt.srr)
1497 daddr = replyopts.opt.opt.faddr;
1500 flowi4_init_output(&fl4, arg->bound_dev_if, 0,
1501 RT_TOS(arg->tos),
1502 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1503 ip_reply_arg_flowi_flags(arg),
1504 daddr, saddr,
1505 tcp_hdr(skb)->source, tcp_hdr(skb)->dest);
1506 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1507 rt = ip_route_output_key(net, &fl4);
1508 if (IS_ERR(rt))
1509 return;
1511 inet = &get_cpu_var(unicast_sock);
1513 inet->tos = arg->tos;
1514 sk = &inet->sk;
1515 sk->sk_priority = skb->priority;
1516 sk->sk_protocol = ip_hdr(skb)->protocol;
1517 sk->sk_bound_dev_if = arg->bound_dev_if;
1518 sock_net_set(sk, net);
1519 __skb_queue_head_init(&sk->sk_write_queue);
1520 sk->sk_sndbuf = sysctl_wmem_default;
1521 ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
1522 &ipc, &rt, MSG_DONTWAIT);
1523 nskb = skb_peek(&sk->sk_write_queue);
1524 if (nskb) {
1525 if (arg->csumoffset >= 0)
1526 *((__sum16 *)skb_transport_header(nskb) +
1527 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1528 arg->csum));
1529 nskb->ip_summed = CHECKSUM_NONE;
1530 skb_orphan(nskb);
1531 skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb));
1532 ip_push_pending_frames(sk, &fl4);
1535 put_cpu_var(unicast_sock);
1537 ip_rt_put(rt);
1540 void __init ip_init(void)
1542 ip_rt_init();
1543 inet_initpeers();
1545 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
1546 igmp_mc_proc_init();
1547 #endif