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x86/paravirt: use percpu_ rather than __get_cpu_var
[linux-2.6/verdex.git] / net / ipv4 / ip_output.c
blob3e7e910c7c0fd6f229a9ee67a10936f24db36a3f
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);
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