?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
netfilter: nf_conntrack_sip: pass data offset to NAT functions
[linux-2.6/x86.git] / net / ipv4 / ip_output.c
blob3451799e3dbf78253d70995d37697a1b546f143d
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The Internet Protocol (IP) output module.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Donald Becker, <becker@super.org>
11 * Alan Cox, <Alan.Cox@linux.org>
12 * Richard Underwood
13 * Stefan Becker, <stefanb@yello.ping.de>
14 * Jorge Cwik, <jorge@laser.satlink.net>
15 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
16 * Hirokazu Takahashi, <taka@valinux.co.jp>
17 *
18 * See ip_input.c for original log
19 *
20 * Fixes:
21 * Alan Cox : Missing nonblock feature in ip_build_xmit.
22 * Mike Kilburn : htons() missing in ip_build_xmit.
23 * Bradford Johnson: Fix faulty handling of some frames when
24 * no route is found.
25 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit
26 * (in case if packet not accepted by
27 * output firewall rules)
28 * Mike McLagan : Routing by source
29 * Alexey Kuznetsov: use new route cache
30 * Andi Kleen: Fix broken PMTU recovery and remove
31 * some redundant tests.
32 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
33 * Andi Kleen : Replace ip_reply with ip_send_reply.
34 * Andi Kleen : Split fast and slow ip_build_xmit path
35 * for decreased register pressure on x86
36 * and more readibility.
37 * Marc Boucher : When call_out_firewall returns FW_QUEUE,
38 * silently drop skb instead of failing with -EPERM.
39 * Detlev Wengorz : Copy protocol for fragments.
40 * Hirokazu Takahashi: HW checksumming for outgoing UDP
41 * datagrams.
42 * Hirokazu Takahashi: sendfile() on UDP works now.
43 */
44
45 #include <asm/uaccess.h>
46 #include <asm/system.h>
47 #include <linux/module.h>
48 #include <linux/types.h>
49 #include <linux/kernel.h>
50 #include <linux/mm.h>
51 #include <linux/string.h>
52 #include <linux/errno.h>
53 #include <linux/highmem.h>
54
55 #include <linux/socket.h>
56 #include <linux/sockios.h>
57 #include <linux/in.h>
58 #include <linux/inet.h>
59 #include <linux/netdevice.h>
60 #include <linux/etherdevice.h>
61 #include <linux/proc_fs.h>
62 #include <linux/stat.h>
63 #include <linux/init.h>
64
65 #include <net/snmp.h>
66 #include <net/ip.h>
67 #include <net/protocol.h>
68 #include <net/route.h>
69 #include <net/xfrm.h>
70 #include <linux/skbuff.h>
71 #include <net/sock.h>
72 #include <net/arp.h>
73 #include <net/icmp.h>
74 #include <net/checksum.h>
75 #include <net/inetpeer.h>
76 #include <linux/igmp.h>
77 #include <linux/netfilter_ipv4.h>
78 #include <linux/netfilter_bridge.h>
79 #include <linux/mroute.h>
80 #include <linux/netlink.h>
81 #include <linux/tcp.h>
82
83 int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
84
85 /* Generate a checksum for an outgoing IP datagram. */
86 __inline__ void ip_send_check(struct iphdr *iph)
87 {
88 iph->check = 0;
89 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
90 }
91
92 int __ip_local_out(struct sk_buff *skb)
93 {
94 struct iphdr *iph = ip_hdr(skb);
95
96 iph->tot_len = htons(skb->len);
97 ip_send_check(iph);
98 return nf_hook(PF_INET, NF_INET_LOCAL_OUT, skb, NULL, skb_dst(skb)->dev,
99 dst_output);
100 }
101
102 int ip_local_out(struct sk_buff *skb)
103 {
104 int err;
105
106 err = __ip_local_out(skb);
107 if (likely(err == 1))
108 err = dst_output(skb);
109
110 return err;
111 }
112 EXPORT_SYMBOL_GPL(ip_local_out);
113
114 /* dev_loopback_xmit for use with netfilter. */
115 static int ip_dev_loopback_xmit(struct sk_buff *newskb)
116 {
117 skb_reset_mac_header(newskb);
118 __skb_pull(newskb, skb_network_offset(newskb));
119 newskb->pkt_type = PACKET_LOOPBACK;
120 newskb->ip_summed = CHECKSUM_UNNECESSARY;
121 WARN_ON(!skb_dst(newskb));
122 netif_rx(newskb);
123 return 0;
124 }
125
126 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
127 {
128 int ttl = inet->uc_ttl;
129
130 if (ttl < 0)
131 ttl = dst_metric(dst, RTAX_HOPLIMIT);
132 return ttl;
133 }
134
135 /*
136 * Add an ip header to a skbuff and send it out.
137 *
138 */
139 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
140 __be32 saddr, __be32 daddr, struct ip_options *opt)
141 {
142 struct inet_sock *inet = inet_sk(sk);
143 struct rtable *rt = skb_rtable(skb);
144 struct iphdr *iph;
145
146 /* Build the IP header. */
147 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0));
148 skb_reset_network_header(skb);
149 iph = ip_hdr(skb);
150 iph->version = 4;
151 iph->ihl = 5;
152 iph->tos = inet->tos;
153 if (ip_dont_fragment(sk, &rt->u.dst))
154 iph->frag_off = htons(IP_DF);
155 else
156 iph->frag_off = 0;
157 iph->ttl = ip_select_ttl(inet, &rt->u.dst);
158 iph->daddr = rt->rt_dst;
159 iph->saddr = rt->rt_src;
160 iph->protocol = sk->sk_protocol;
161 ip_select_ident(iph, &rt->u.dst, sk);
162
163 if (opt && opt->optlen) {
164 iph->ihl += opt->optlen>>2;
165 ip_options_build(skb, opt, daddr, rt, 0);
166 }
167
168 skb->priority = sk->sk_priority;
169 skb->mark = sk->sk_mark;
170
171 /* Send it out. */
172 return ip_local_out(skb);
173 }
174
175 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
176
177 static inline int ip_finish_output2(struct sk_buff *skb)
178 {
179 struct dst_entry *dst = skb_dst(skb);
180 struct rtable *rt = (struct rtable *)dst;
181 struct net_device *dev = dst->dev;
182 unsigned int hh_len = LL_RESERVED_SPACE(dev);
183
184 if (rt->rt_type == RTN_MULTICAST) {
185 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
186 } else if (rt->rt_type == RTN_BROADCAST)
187 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len);
188
189 /* Be paranoid, rather than too clever. */
190 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
191 struct sk_buff *skb2;
192
193 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
194 if (skb2 == NULL) {
195 kfree_skb(skb);
196 return -ENOMEM;
197 }
198 if (skb->sk)
199 skb_set_owner_w(skb2, skb->sk);
200 kfree_skb(skb);
201 skb = skb2;
202 }
203
204 if (dst->hh)
205 return neigh_hh_output(dst->hh, skb);
206 else if (dst->neighbour)
207 return dst->neighbour->output(skb);
208
209 if (net_ratelimit())
210 printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n");
211 kfree_skb(skb);
212 return -EINVAL;
213 }
214
215 static inline int ip_skb_dst_mtu(struct sk_buff *skb)
216 {
217 struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
218
219 return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
220 skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
221 }
222
223 static int ip_finish_output(struct sk_buff *skb)
224 {
225 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
226 /* Policy lookup after SNAT yielded a new policy */
227 if (skb_dst(skb)->xfrm != NULL) {
228 IPCB(skb)->flags |= IPSKB_REROUTED;
229 return dst_output(skb);
230 }
231 #endif
232 if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb))
233 return ip_fragment(skb, ip_finish_output2);
234 else
235 return ip_finish_output2(skb);
236 }
237
238 int ip_mc_output(struct sk_buff *skb)
239 {
240 struct sock *sk = skb->sk;
241 struct rtable *rt = skb_rtable(skb);
242 struct net_device *dev = rt->u.dst.dev;
243
244 /*
245 * If the indicated interface is up and running, send the packet.
246 */
247 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
248
249 skb->dev = dev;
250 skb->protocol = htons(ETH_P_IP);
251
252 /*
253 * Multicasts are looped back for other local users
254 */
255
256 if (rt->rt_flags&RTCF_MULTICAST) {
257 if (sk_mc_loop(sk)
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 &&
268 ((rt->rt_flags & RTCF_LOCAL) ||
269 !(IPCB(skb)->flags & IPSKB_FORWARDED))
270 #endif
271 ) {
272 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
273 if (newskb)
274 NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb,
275 NULL, newskb->dev,
276 ip_dev_loopback_xmit);
277 }
278
279 /* Multicasts with ttl 0 must not go beyond the host */
280
281 if (ip_hdr(skb)->ttl == 0) {
282 kfree_skb(skb);
283 return 0;
284 }
285 }
286
287 if (rt->rt_flags&RTCF_BROADCAST) {
288 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
289 if (newskb)
290 NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb, NULL,
291 newskb->dev, ip_dev_loopback_xmit);
292 }
293
294 return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, skb->dev,
295 ip_finish_output,
296 !(IPCB(skb)->flags & IPSKB_REROUTED));
297 }
298
299 int ip_output(struct sk_buff *skb)
300 {
301 struct net_device *dev = skb_dst(skb)->dev;
302
303 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
304
305 skb->dev = dev;
306 skb->protocol = htons(ETH_P_IP);
307
308 return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, dev,
309 ip_finish_output,
310 !(IPCB(skb)->flags & IPSKB_REROUTED));
311 }
312
313 int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
314 {
315 struct sock *sk = skb->sk;
316 struct inet_sock *inet = inet_sk(sk);
317 struct ip_options *opt = inet->opt;
318 struct rtable *rt;
319 struct iphdr *iph;
320
321 /* Skip all of this if the packet is already routed,
322 * f.e. by something like SCTP.
323 */
324 rt = skb_rtable(skb);
325 if (rt != NULL)
326 goto packet_routed;
327
328 /* Make sure we can route this packet. */
329 rt = (struct rtable *)__sk_dst_check(sk, 0);
330 if (rt == NULL) {
331 __be32 daddr;
332
333 /* Use correct destination address if we have options. */
334 daddr = inet->inet_daddr;
335 if(opt && opt->srr)
336 daddr = opt->faddr;
337
338 {
339 struct flowi fl = { .oif = sk->sk_bound_dev_if,
340 .mark = sk->sk_mark,
341 .nl_u = { .ip4_u =
342 { .daddr = daddr,
343 .saddr = inet->inet_saddr,
344 .tos = RT_CONN_FLAGS(sk) } },
345 .proto = sk->sk_protocol,
346 .flags = inet_sk_flowi_flags(sk),
347 .uli_u = { .ports =
348 { .sport = inet->inet_sport,
349 .dport = inet->inet_dport } } };
350
351 /* If this fails, retransmit mechanism of transport layer will
352 * keep trying until route appears or the connection times
353 * itself out.
354 */
355 security_sk_classify_flow(sk, &fl);
356 if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0))
357 goto no_route;
358 }
359 sk_setup_caps(sk, &rt->u.dst);
360 }
361 skb_dst_set(skb, dst_clone(&rt->u.dst));
362
363 packet_routed:
364 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
365 goto no_route;
366
367 /* OK, we know where to send it, allocate and build IP header. */
368 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0));
369 skb_reset_network_header(skb);
370 iph = ip_hdr(skb);
371 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
372 if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok)
373 iph->frag_off = htons(IP_DF);
374 else
375 iph->frag_off = 0;
376 iph->ttl = ip_select_ttl(inet, &rt->u.dst);
377 iph->protocol = sk->sk_protocol;
378 iph->saddr = rt->rt_src;
379 iph->daddr = rt->rt_dst;
380 /* Transport layer set skb->h.foo itself. */
381
382 if (opt && opt->optlen) {
383 iph->ihl += opt->optlen >> 2;
384 ip_options_build(skb, opt, inet->inet_daddr, rt, 0);
385 }
386
387 ip_select_ident_more(iph, &rt->u.dst, sk,
388 (skb_shinfo(skb)->gso_segs ?: 1) - 1);
389
390 skb->priority = sk->sk_priority;
391 skb->mark = sk->sk_mark;
392
393 return ip_local_out(skb);
394
395 no_route:
396 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
397 kfree_skb(skb);
398 return -EHOSTUNREACH;
399 }
400
401
402 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
403 {
404 to->pkt_type = from->pkt_type;
405 to->priority = from->priority;
406 to->protocol = from->protocol;
407 skb_dst_drop(to);
408 skb_dst_set(to, dst_clone(skb_dst(from)));
409 to->dev = from->dev;
410 to->mark = from->mark;
411
412 /* Copy the flags to each fragment. */
413 IPCB(to)->flags = IPCB(from)->flags;
414
415 #ifdef CONFIG_NET_SCHED
416 to->tc_index = from->tc_index;
417 #endif
418 nf_copy(to, from);
419 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
420 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
421 to->nf_trace = from->nf_trace;
422 #endif
423 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
424 to->ipvs_property = from->ipvs_property;
425 #endif
426 skb_copy_secmark(to, from);
427 }
428
429 /*
430 * This IP datagram is too large to be sent in one piece. Break it up into
431 * smaller pieces (each of size equal to IP header plus
432 * a block of the data of the original IP data part) that will yet fit in a
433 * single device frame, and queue such a frame for sending.
434 */
435
436 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
437 {
438 struct iphdr *iph;
439 int raw = 0;
440 int ptr;
441 struct net_device *dev;
442 struct sk_buff *skb2;
443 unsigned int mtu, hlen, left, len, ll_rs, pad;
444 int offset;
445 __be16 not_last_frag;
446 struct rtable *rt = skb_rtable(skb);
447 int err = 0;
448
449 dev = rt->u.dst.dev;
450
451 /*
452 * Point into the IP datagram header.
453 */
454
455 iph = ip_hdr(skb);
456
457 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) {
458 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
459 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
460 htonl(ip_skb_dst_mtu(skb)));
461 kfree_skb(skb);
462 return -EMSGSIZE;
463 }
464
465 /*
466 * Setup starting values.
467 */
468
469 hlen = iph->ihl * 4;
470 mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */
471 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
472
473 /* When frag_list is given, use it. First, check its validity:
474 * some transformers could create wrong frag_list or break existing
475 * one, it is not prohibited. In this case fall back to copying.
476 *
477 * LATER: this step can be merged to real generation of fragments,
478 * we can switch to copy when see the first bad fragment.
479 */
480 if (skb_has_frags(skb)) {
481 struct sk_buff *frag;
482 int first_len = skb_pagelen(skb);
483 int truesizes = 0;
484
485 if (first_len - hlen > mtu ||
486 ((first_len - hlen) & 7) ||
487 (iph->frag_off & htons(IP_MF|IP_OFFSET)) ||
488 skb_cloned(skb))
489 goto slow_path;
490
491 skb_walk_frags(skb, frag) {
492 /* Correct geometry. */
493 if (frag->len > mtu ||
494 ((frag->len & 7) && frag->next) ||
495 skb_headroom(frag) < hlen)
496 goto slow_path;
497
498 /* Partially cloned skb? */
499 if (skb_shared(frag))
500 goto slow_path;
501
502 BUG_ON(frag->sk);
503 if (skb->sk) {
504 frag->sk = skb->sk;
505 frag->destructor = sock_wfree;
506 }
507 truesizes += frag->truesize;
508 }
509
510 /* Everything is OK. Generate! */
511
512 err = 0;
513 offset = 0;
514 frag = skb_shinfo(skb)->frag_list;
515 skb_frag_list_init(skb);
516 skb->data_len = first_len - skb_headlen(skb);
517 skb->truesize -= truesizes;
518 skb->len = first_len;
519 iph->tot_len = htons(first_len);
520 iph->frag_off = htons(IP_MF);
521 ip_send_check(iph);
522
523 for (;;) {
524 /* Prepare header of the next frame,
525 * before previous one went down. */
526 if (frag) {
527 frag->ip_summed = CHECKSUM_NONE;
528 skb_reset_transport_header(frag);
529 __skb_push(frag, hlen);
530 skb_reset_network_header(frag);
531 memcpy(skb_network_header(frag), iph, hlen);
532 iph = ip_hdr(frag);
533 iph->tot_len = htons(frag->len);
534 ip_copy_metadata(frag, skb);
535 if (offset == 0)
536 ip_options_fragment(frag);
537 offset += skb->len - hlen;
538 iph->frag_off = htons(offset>>3);
539 if (frag->next != NULL)
540 iph->frag_off |= htons(IP_MF);
541 /* Ready, complete checksum */
542 ip_send_check(iph);
543 }
544
545 err = output(skb);
546
547 if (!err)
548 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
549 if (err || !frag)
550 break;
551
552 skb = frag;
553 frag = skb->next;
554 skb->next = NULL;
555 }
556
557 if (err == 0) {
558 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
559 return 0;
560 }
561
562 while (frag) {
563 skb = frag->next;
564 kfree_skb(frag);
565 frag = skb;
566 }
567 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
568 return err;
569 }
570
571 slow_path:
572 left = skb->len - hlen; /* Space per frame */
573 ptr = raw + hlen; /* Where to start from */
574
575 /* for bridged IP traffic encapsulated inside f.e. a vlan header,
576 * we need to make room for the encapsulating header
577 */
578 pad = nf_bridge_pad(skb);
579 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad);
580 mtu -= pad;
581
582 /*
583 * Fragment the datagram.
584 */
585
586 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
587 not_last_frag = iph->frag_off & htons(IP_MF);
588
589 /*
590 * Keep copying data until we run out.
591 */
592
593 while (left > 0) {
594 len = left;
595 /* IF: it doesn't fit, use 'mtu' - the data space left */
596 if (len > mtu)
597 len = mtu;
598 /* IF: we are not sending upto and including the packet end
599 then align the next start on an eight byte boundary */
600 if (len < left) {
601 len &= ~7;
602 }
603 /*
604 * Allocate buffer.
605 */
606
607 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) {
608 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n");
609 err = -ENOMEM;
610 goto fail;
611 }
612
613 /*
614 * Set up data on packet
615 */
616
617 ip_copy_metadata(skb2, skb);
618 skb_reserve(skb2, ll_rs);
619 skb_put(skb2, len + hlen);
620 skb_reset_network_header(skb2);
621 skb2->transport_header = skb2->network_header + hlen;
622
623 /*
624 * Charge the memory for the fragment to any owner
625 * it might possess
626 */
627
628 if (skb->sk)
629 skb_set_owner_w(skb2, skb->sk);
630
631 /*
632 * Copy the packet header into the new buffer.
633 */
634
635 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
636
637 /*
638 * Copy a block of the IP datagram.
639 */
640 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
641 BUG();
642 left -= len;
643
644 /*
645 * Fill in the new header fields.
646 */
647 iph = ip_hdr(skb2);
648 iph->frag_off = htons((offset >> 3));
649
650 /* ANK: dirty, but effective trick. Upgrade options only if
651 * the segment to be fragmented was THE FIRST (otherwise,
652 * options are already fixed) and make it ONCE
653 * on the initial skb, so that all the following fragments
654 * will inherit fixed options.
655 */
656 if (offset == 0)
657 ip_options_fragment(skb);
658
659 /*
660 * Added AC : If we are fragmenting a fragment that's not the
661 * last fragment then keep MF on each bit
662 */
663 if (left > 0 || not_last_frag)
664 iph->frag_off |= htons(IP_MF);
665 ptr += len;
666 offset += len;
667
668 /*
669 * Put this fragment into the sending queue.
670 */
671 iph->tot_len = htons(len + hlen);
672
673 ip_send_check(iph);
674
675 err = output(skb2);
676 if (err)
677 goto fail;
678
679 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
680 }
681 kfree_skb(skb);
682 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
683 return err;
684
685 fail:
686 kfree_skb(skb);
687 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
688 return err;
689 }
690
691 EXPORT_SYMBOL(ip_fragment);
692
693 int
694 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
695 {
696 struct iovec *iov = from;
697
698 if (skb->ip_summed == CHECKSUM_PARTIAL) {
699 if (memcpy_fromiovecend(to, iov, offset, len) < 0)
700 return -EFAULT;
701 } else {
702 __wsum csum = 0;
703 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
704 return -EFAULT;
705 skb->csum = csum_block_add(skb->csum, csum, odd);
706 }
707 return 0;
708 }
709
710 static inline __wsum
711 csum_page(struct page *page, int offset, int copy)
712 {
713 char *kaddr;
714 __wsum csum;
715 kaddr = kmap(page);
716 csum = csum_partial(kaddr + offset, copy, 0);
717 kunmap(page);
718 return csum;
719 }
720
721 static inline int ip_ufo_append_data(struct sock *sk,
722 int getfrag(void *from, char *to, int offset, int len,
723 int odd, struct sk_buff *skb),
724 void *from, int length, int hh_len, int fragheaderlen,
725 int transhdrlen, int mtu, unsigned int flags)
726 {
727 struct sk_buff *skb;
728 int err;
729
730 /* There is support for UDP fragmentation offload by network
731 * device, so create one single skb packet containing complete
732 * udp datagram
733 */
734 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
735 skb = sock_alloc_send_skb(sk,
736 hh_len + fragheaderlen + transhdrlen + 20,
737 (flags & MSG_DONTWAIT), &err);
738
739 if (skb == NULL)
740 return err;
741
742 /* reserve space for Hardware header */
743 skb_reserve(skb, hh_len);
744
745 /* create space for UDP/IP header */
746 skb_put(skb, fragheaderlen + transhdrlen);
747
748 /* initialize network header pointer */
749 skb_reset_network_header(skb);
750
751 /* initialize protocol header pointer */
752 skb->transport_header = skb->network_header + fragheaderlen;
753
754 skb->ip_summed = CHECKSUM_PARTIAL;
755 skb->csum = 0;
756 sk->sk_sndmsg_off = 0;
757
758 /* specify the length of each IP datagram fragment */
759 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
760 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
761 __skb_queue_tail(&sk->sk_write_queue, skb);
762 }
763
764 return skb_append_datato_frags(sk, skb, getfrag, from,
765 (length - transhdrlen));
766 }
767
768 /*
769 * ip_append_data() and ip_append_page() can make one large IP datagram
770 * from many pieces of data. Each pieces will be holded on the socket
771 * until ip_push_pending_frames() is called. Each piece can be a page
772 * or non-page data.
773 *
774 * Not only UDP, other transport protocols - e.g. raw sockets - can use
775 * this interface potentially.
776 *
777 * LATER: length must be adjusted by pad at tail, when it is required.
778 */
779 int ip_append_data(struct sock *sk,
780 int getfrag(void *from, char *to, int offset, int len,
781 int odd, struct sk_buff *skb),
782 void *from, int length, int transhdrlen,
783 struct ipcm_cookie *ipc, struct rtable **rtp,
784 unsigned int flags)
785 {
786 struct inet_sock *inet = inet_sk(sk);
787 struct sk_buff *skb;
788
789 struct ip_options *opt = NULL;
790 int hh_len;
791 int exthdrlen;
792 int mtu;
793 int copy;
794 int err;
795 int offset = 0;
796 unsigned int maxfraglen, fragheaderlen;
797 int csummode = CHECKSUM_NONE;
798 struct rtable *rt;
799
800 if (flags&MSG_PROBE)
801 return 0;
802
803 if (skb_queue_empty(&sk->sk_write_queue)) {
804 /*
805 * setup for corking.
806 */
807 opt = ipc->opt;
808 if (opt) {
809 if (inet->cork.opt == NULL) {
810 inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation);
811 if (unlikely(inet->cork.opt == NULL))
812 return -ENOBUFS;
813 }
814 memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen);
815 inet->cork.flags |= IPCORK_OPT;
816 inet->cork.addr = ipc->addr;
817 }
818 rt = *rtp;
819 if (unlikely(!rt))
820 return -EFAULT;
821 /*
822 * We steal reference to this route, caller should not release it
823 */
824 *rtp = NULL;
825 inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ?
826 rt->u.dst.dev->mtu :
827 dst_mtu(rt->u.dst.path);
828 inet->cork.dst = &rt->u.dst;
829 inet->cork.length = 0;
830 sk->sk_sndmsg_page = NULL;
831 sk->sk_sndmsg_off = 0;
832 if ((exthdrlen = rt->u.dst.header_len) != 0) {
833 length += exthdrlen;
834 transhdrlen += exthdrlen;
835 }
836 } else {
837 rt = (struct rtable *)inet->cork.dst;
838 if (inet->cork.flags & IPCORK_OPT)
839 opt = inet->cork.opt;
840
841 transhdrlen = 0;
842 exthdrlen = 0;
843 mtu = inet->cork.fragsize;
844 }
845 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
846
847 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
848 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
849
850 if (inet->cork.length + length > 0xFFFF - fragheaderlen) {
851 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport,
852 mtu-exthdrlen);
853 return -EMSGSIZE;
854 }
855
856 /*
857 * transhdrlen > 0 means that this is the first fragment and we wish
858 * it won't be fragmented in the future.
859 */
860 if (transhdrlen &&
861 length + fragheaderlen <= mtu &&
862 rt->u.dst.dev->features & NETIF_F_V4_CSUM &&
863 !exthdrlen)
864 csummode = CHECKSUM_PARTIAL;
865
866 inet->cork.length += length;
867 if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) &&
868 (sk->sk_protocol == IPPROTO_UDP) &&
869 (rt->u.dst.dev->features & NETIF_F_UFO)) {
870 err = ip_ufo_append_data(sk, getfrag, from, length, hh_len,
871 fragheaderlen, transhdrlen, mtu,
872 flags);
873 if (err)
874 goto error;
875 return 0;
876 }
877
878 /* So, what's going on in the loop below?
879 *
880 * We use calculated fragment length to generate chained skb,
881 * each of segments is IP fragment ready for sending to network after
882 * adding appropriate IP header.
883 */
884
885 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
886 goto alloc_new_skb;
887
888 while (length > 0) {
889 /* Check if the remaining data fits into current packet. */
890 copy = mtu - skb->len;
891 if (copy < length)
892 copy = maxfraglen - skb->len;
893 if (copy <= 0) {
894 char *data;
895 unsigned int datalen;
896 unsigned int fraglen;
897 unsigned int fraggap;
898 unsigned int alloclen;
899 struct sk_buff *skb_prev;
900 alloc_new_skb:
901 skb_prev = skb;
902 if (skb_prev)
903 fraggap = skb_prev->len - maxfraglen;
904 else
905 fraggap = 0;
906
907 /*
908 * If remaining data exceeds the mtu,
909 * we know we need more fragment(s).
910 */
911 datalen = length + fraggap;
912 if (datalen > mtu - fragheaderlen)
913 datalen = maxfraglen - fragheaderlen;
914 fraglen = datalen + fragheaderlen;
915
916 if ((flags & MSG_MORE) &&
917 !(rt->u.dst.dev->features&NETIF_F_SG))
918 alloclen = mtu;
919 else
920 alloclen = datalen + fragheaderlen;
921
922 /* The last fragment gets additional space at tail.
923 * Note, with MSG_MORE we overallocate on fragments,
924 * because we have no idea what fragment will be
925 * the last.
926 */
927 if (datalen == length + fraggap)
928 alloclen += rt->u.dst.trailer_len;
929
930 if (transhdrlen) {
931 skb = sock_alloc_send_skb(sk,
932 alloclen + hh_len + 15,
933 (flags & MSG_DONTWAIT), &err);
934 } else {
935 skb = NULL;
936 if (atomic_read(&sk->sk_wmem_alloc) <=
937 2 * sk->sk_sndbuf)
938 skb = sock_wmalloc(sk,
939 alloclen + hh_len + 15, 1,
940 sk->sk_allocation);
941 if (unlikely(skb == NULL))
942 err = -ENOBUFS;
943 else
944 /* only the initial fragment is
945 time stamped */
946 ipc->shtx.flags = 0;
947 }
948 if (skb == NULL)
949 goto error;
950
951 /*
952 * Fill in the control structures
953 */
954 skb->ip_summed = csummode;
955 skb->csum = 0;
956 skb_reserve(skb, hh_len);
957 *skb_tx(skb) = ipc->shtx;
958
959 /*
960 * Find where to start putting bytes.
961 */
962 data = skb_put(skb, fraglen);
963 skb_set_network_header(skb, exthdrlen);
964 skb->transport_header = (skb->network_header +
965 fragheaderlen);
966 data += fragheaderlen;
967
968 if (fraggap) {
969 skb->csum = skb_copy_and_csum_bits(
970 skb_prev, maxfraglen,
971 data + transhdrlen, fraggap, 0);
972 skb_prev->csum = csum_sub(skb_prev->csum,
973 skb->csum);
974 data += fraggap;
975 pskb_trim_unique(skb_prev, maxfraglen);
976 }
977
978 copy = datalen - transhdrlen - fraggap;
979 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
980 err = -EFAULT;
981 kfree_skb(skb);
982 goto error;
983 }
984
985 offset += copy;
986 length -= datalen - fraggap;
987 transhdrlen = 0;
988 exthdrlen = 0;
989 csummode = CHECKSUM_NONE;
990
991 /*
992 * Put the packet on the pending queue.
993 */
994 __skb_queue_tail(&sk->sk_write_queue, skb);
995 continue;
996 }
997
998 if (copy > length)
999 copy = length;
1000
1001 if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
1002 unsigned int off;
1003
1004 off = skb->len;
1005 if (getfrag(from, skb_put(skb, copy),
1006 offset, copy, off, skb) < 0) {
1007 __skb_trim(skb, off);
1008 err = -EFAULT;
1009 goto error;
1010 }
1011 } else {
1012 int i = skb_shinfo(skb)->nr_frags;
1013 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1014 struct page *page = sk->sk_sndmsg_page;
1015 int off = sk->sk_sndmsg_off;
1016 unsigned int left;
1017
1018 if (page && (left = PAGE_SIZE - off) > 0) {
1019 if (copy >= left)
1020 copy = left;
1021 if (page != frag->page) {
1022 if (i == MAX_SKB_FRAGS) {
1023 err = -EMSGSIZE;
1024 goto error;
1025 }
1026 get_page(page);
1027 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1028 frag = &skb_shinfo(skb)->frags[i];
1029 }
1030 } else if (i < MAX_SKB_FRAGS) {
1031 if (copy > PAGE_SIZE)
1032 copy = PAGE_SIZE;
1033 page = alloc_pages(sk->sk_allocation, 0);
1034 if (page == NULL) {
1035 err = -ENOMEM;
1036 goto error;
1037 }
1038 sk->sk_sndmsg_page = page;
1039 sk->sk_sndmsg_off = 0;
1040
1041 skb_fill_page_desc(skb, i, page, 0, 0);
1042 frag = &skb_shinfo(skb)->frags[i];
1043 } else {
1044 err = -EMSGSIZE;
1045 goto error;
1046 }
1047 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1048 err = -EFAULT;
1049 goto error;
1050 }
1051 sk->sk_sndmsg_off += copy;
1052 frag->size += copy;
1053 skb->len += copy;
1054 skb->data_len += copy;
1055 skb->truesize += copy;
1056 atomic_add(copy, &sk->sk_wmem_alloc);
1057 }
1058 offset += copy;
1059 length -= copy;
1060 }
1061
1062 return 0;
1063
1064 error:
1065 inet->cork.length -= length;
1066 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1067 return err;
1068 }
1069
1070 ssize_t ip_append_page(struct sock *sk, struct page *page,
1071 int offset, size_t size, int flags)
1072 {
1073 struct inet_sock *inet = inet_sk(sk);
1074 struct sk_buff *skb;
1075 struct rtable *rt;
1076 struct ip_options *opt = NULL;
1077 int hh_len;
1078 int mtu;
1079 int len;
1080 int err;
1081 unsigned int maxfraglen, fragheaderlen, fraggap;
1082
1083 if (inet->hdrincl)
1084 return -EPERM;
1085
1086 if (flags&MSG_PROBE)
1087 return 0;
1088
1089 if (skb_queue_empty(&sk->sk_write_queue))
1090 return -EINVAL;
1091
1092 rt = (struct rtable *)inet->cork.dst;
1093 if (inet->cork.flags & IPCORK_OPT)
1094 opt = inet->cork.opt;
1095
1096 if (!(rt->u.dst.dev->features&NETIF_F_SG))
1097 return -EOPNOTSUPP;
1098
1099 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
1100 mtu = inet->cork.fragsize;
1101
1102 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1103 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1104
1105 if (inet->cork.length + size > 0xFFFF - fragheaderlen) {
1106 ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport, mtu);
1107 return -EMSGSIZE;
1108 }
1109
1110 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1111 return -EINVAL;
1112
1113 inet->cork.length += size;
1114 if ((sk->sk_protocol == IPPROTO_UDP) &&
1115 (rt->u.dst.dev->features & NETIF_F_UFO)) {
1116 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1117 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1118 }
1119
1120
1121 while (size > 0) {
1122 int i;
1123
1124 if (skb_is_gso(skb))
1125 len = size;
1126 else {
1127
1128 /* Check if the remaining data fits into current packet. */
1129 len = mtu - skb->len;
1130 if (len < size)
1131 len = maxfraglen - skb->len;
1132 }
1133 if (len <= 0) {
1134 struct sk_buff *skb_prev;
1135 int alloclen;
1136
1137 skb_prev = skb;
1138 fraggap = skb_prev->len - maxfraglen;
1139
1140 alloclen = fragheaderlen + hh_len + fraggap + 15;
1141 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1142 if (unlikely(!skb)) {
1143 err = -ENOBUFS;
1144 goto error;
1145 }
1146
1147 /*
1148 * Fill in the control structures
1149 */
1150 skb->ip_summed = CHECKSUM_NONE;
1151 skb->csum = 0;
1152 skb_reserve(skb, hh_len);
1153
1154 /*
1155 * Find where to start putting bytes.
1156 */
1157 skb_put(skb, fragheaderlen + fraggap);
1158 skb_reset_network_header(skb);
1159 skb->transport_header = (skb->network_header +
1160 fragheaderlen);
1161 if (fraggap) {
1162 skb->csum = skb_copy_and_csum_bits(skb_prev,
1163 maxfraglen,
1164 skb_transport_header(skb),
1165 fraggap, 0);
1166 skb_prev->csum = csum_sub(skb_prev->csum,
1167 skb->csum);
1168 pskb_trim_unique(skb_prev, maxfraglen);
1169 }
1170
1171 /*
1172 * Put the packet on the pending queue.
1173 */
1174 __skb_queue_tail(&sk->sk_write_queue, skb);
1175 continue;
1176 }
1177
1178 i = skb_shinfo(skb)->nr_frags;
1179 if (len > size)
1180 len = size;
1181 if (skb_can_coalesce(skb, i, page, offset)) {
1182 skb_shinfo(skb)->frags[i-1].size += len;
1183 } else if (i < MAX_SKB_FRAGS) {
1184 get_page(page);
1185 skb_fill_page_desc(skb, i, page, offset, len);
1186 } else {
1187 err = -EMSGSIZE;
1188 goto error;
1189 }
1190
1191 if (skb->ip_summed == CHECKSUM_NONE) {
1192 __wsum csum;
1193 csum = csum_page(page, offset, len);
1194 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1195 }
1196
1197 skb->len += len;
1198 skb->data_len += len;
1199 skb->truesize += len;
1200 atomic_add(len, &sk->sk_wmem_alloc);
1201 offset += len;
1202 size -= len;
1203 }
1204 return 0;
1205
1206 error:
1207 inet->cork.length -= size;
1208 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1209 return err;
1210 }
1211
1212 static void ip_cork_release(struct inet_sock *inet)
1213 {
1214 inet->cork.flags &= ~IPCORK_OPT;
1215 kfree(inet->cork.opt);
1216 inet->cork.opt = NULL;
1217 dst_release(inet->cork.dst);
1218 inet->cork.dst = NULL;
1219 }
1220
1221 /*
1222 * Combined all pending IP fragments on the socket as one IP datagram
1223 * and push them out.
1224 */
1225 int ip_push_pending_frames(struct sock *sk)
1226 {
1227 struct sk_buff *skb, *tmp_skb;
1228 struct sk_buff **tail_skb;
1229 struct inet_sock *inet = inet_sk(sk);
1230 struct net *net = sock_net(sk);
1231 struct ip_options *opt = NULL;
1232 struct rtable *rt = (struct rtable *)inet->cork.dst;
1233 struct iphdr *iph;
1234 __be16 df = 0;
1235 __u8 ttl;
1236 int err = 0;
1237
1238 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1239 goto out;
1240 tail_skb = &(skb_shinfo(skb)->frag_list);
1241
1242 /* move skb->data to ip header from ext header */
1243 if (skb->data < skb_network_header(skb))
1244 __skb_pull(skb, skb_network_offset(skb));
1245 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1246 __skb_pull(tmp_skb, skb_network_header_len(skb));
1247 *tail_skb = tmp_skb;
1248 tail_skb = &(tmp_skb->next);
1249 skb->len += tmp_skb->len;
1250 skb->data_len += tmp_skb->len;
1251 skb->truesize += tmp_skb->truesize;
1252 tmp_skb->destructor = NULL;
1253 tmp_skb->sk = NULL;
1254 }
1255
1256 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1257 * to fragment the frame generated here. No matter, what transforms
1258 * how transforms change size of the packet, it will come out.
1259 */
1260 if (inet->pmtudisc < IP_PMTUDISC_DO)
1261 skb->local_df = 1;
1262
1263 /* DF bit is set when we want to see DF on outgoing frames.
1264 * If local_df is set too, we still allow to fragment this frame
1265 * locally. */
1266 if (inet->pmtudisc >= IP_PMTUDISC_DO ||
1267 (skb->len <= dst_mtu(&rt->u.dst) &&
1268 ip_dont_fragment(sk, &rt->u.dst)))
1269 df = htons(IP_DF);
1270
1271 if (inet->cork.flags & IPCORK_OPT)
1272 opt = inet->cork.opt;
1273
1274 if (rt->rt_type == RTN_MULTICAST)
1275 ttl = inet->mc_ttl;
1276 else
1277 ttl = ip_select_ttl(inet, &rt->u.dst);
1278
1279 iph = (struct iphdr *)skb->data;
1280 iph->version = 4;
1281 iph->ihl = 5;
1282 if (opt) {
1283 iph->ihl += opt->optlen>>2;
1284 ip_options_build(skb, opt, inet->cork.addr, rt, 0);
1285 }
1286 iph->tos = inet->tos;
1287 iph->frag_off = df;
1288 ip_select_ident(iph, &rt->u.dst, sk);
1289 iph->ttl = ttl;
1290 iph->protocol = sk->sk_protocol;
1291 iph->saddr = rt->rt_src;
1292 iph->daddr = rt->rt_dst;
1293
1294 skb->priority = sk->sk_priority;
1295 skb->mark = sk->sk_mark;
1296 /*
1297 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1298 * on dst refcount
1299 */
1300 inet->cork.dst = NULL;
1301 skb_dst_set(skb, &rt->u.dst);
1302
1303 if (iph->protocol == IPPROTO_ICMP)
1304 icmp_out_count(net, ((struct icmphdr *)
1305 skb_transport_header(skb))->type);
1306
1307 /* Netfilter gets whole the not fragmented skb. */
1308 err = ip_local_out(skb);
1309 if (err) {
1310 if (err > 0)
1311 err = net_xmit_errno(err);
1312 if (err)
1313 goto error;
1314 }
1315
1316 out:
1317 ip_cork_release(inet);
1318 return err;
1319
1320 error:
1321 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1322 goto out;
1323 }
1324
1325 /*
1326 * Throw away all pending data on the socket.
1327 */
1328 void ip_flush_pending_frames(struct sock *sk)
1329 {
1330 struct sk_buff *skb;
1331
1332 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
1333 kfree_skb(skb);
1334
1335 ip_cork_release(inet_sk(sk));
1336 }
1337
1338
1339 /*
1340 * Fetch data from kernel space and fill in checksum if needed.
1341 */
1342 static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1343 int len, int odd, struct sk_buff *skb)
1344 {
1345 __wsum csum;
1346
1347 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1348 skb->csum = csum_block_add(skb->csum, csum, odd);
1349 return 0;
1350 }
1351
1352 /*
1353 * Generic function to send a packet as reply to another packet.
1354 * Used to send TCP resets so far. ICMP should use this function too.
1355 *
1356 * Should run single threaded per socket because it uses the sock
1357 * structure to pass arguments.
1358 */
1359 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
1360 unsigned int len)
1361 {
1362 struct inet_sock *inet = inet_sk(sk);
1363 struct {
1364 struct ip_options opt;
1365 char data[40];
1366 } replyopts;
1367 struct ipcm_cookie ipc;
1368 __be32 daddr;
1369 struct rtable *rt = skb_rtable(skb);
1370
1371 if (ip_options_echo(&replyopts.opt, skb))
1372 return;
1373
1374 daddr = ipc.addr = rt->rt_src;
1375 ipc.opt = NULL;
1376 ipc.shtx.flags = 0;
1377
1378 if (replyopts.opt.optlen) {
1379 ipc.opt = &replyopts.opt;
1380
1381 if (ipc.opt->srr)
1382 daddr = replyopts.opt.faddr;
1383 }
1384
1385 {
1386 struct flowi fl = { .oif = arg->bound_dev_if,
1387 .nl_u = { .ip4_u =
1388 { .daddr = daddr,
1389 .saddr = rt->rt_spec_dst,
1390 .tos = RT_TOS(ip_hdr(skb)->tos) } },
1391 /* Not quite clean, but right. */
1392 .uli_u = { .ports =
1393 { .sport = tcp_hdr(skb)->dest,
1394 .dport = tcp_hdr(skb)->source } },
1395 .proto = sk->sk_protocol,
1396 .flags = ip_reply_arg_flowi_flags(arg) };
1397 security_skb_classify_flow(skb, &fl);
1398 if (ip_route_output_key(sock_net(sk), &rt, &fl))
1399 return;
1400 }
1401
1402 /* And let IP do all the hard work.
1403
1404 This chunk is not reenterable, hence spinlock.
1405 Note that it uses the fact, that this function is called
1406 with locally disabled BH and that sk cannot be already spinlocked.
1407 */
1408 bh_lock_sock(sk);
1409 inet->tos = ip_hdr(skb)->tos;
1410 sk->sk_priority = skb->priority;
1411 sk->sk_protocol = ip_hdr(skb)->protocol;
1412 sk->sk_bound_dev_if = arg->bound_dev_if;
1413 ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
1414 &ipc, &rt, MSG_DONTWAIT);
1415 if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
1416 if (arg->csumoffset >= 0)
1417 *((__sum16 *)skb_transport_header(skb) +
1418 arg->csumoffset) = csum_fold(csum_add(skb->csum,
1419 arg->csum));
1420 skb->ip_summed = CHECKSUM_NONE;
1421 ip_push_pending_frames(sk);
1422 }
1423
1424 bh_unlock_sock(sk);
1425
1426 ip_rt_put(rt);
1427 }
1428
1429 void __init ip_init(void)
1430 {
1431 ip_rt_init();
1432 inet_initpeers();
1433
1434 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
1435 igmp_mc_proc_init();
1436 #endif
1437 }
1438
1439 EXPORT_SYMBOL(ip_generic_getfrag);
1440 EXPORT_SYMBOL(ip_queue_xmit);
1441 EXPORT_SYMBOL(ip_send_check);
x86 "subsystem" repository