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Adding support for MOXA ART SoC. Testing port of linux-2.6.32.60-moxart.
[linux-3.6.7-moxart.git] / net / ipv4 / ip_output.c
blob94ad7ea35a419890dfde600cf302c2088c6dd1eb
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 <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>
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 EXPORT_SYMBOL(sysctl_ip_default_ttl);
85
86 /* Generate a checksum for an outgoing IP datagram. */
87 __inline__ void ip_send_check(struct iphdr *iph)
88 {
89 iph->check = 0;
90 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
91 }
92 EXPORT_SYMBOL(ip_send_check);
93
94 int __ip_local_out(struct sk_buff *skb)
95 {
96 struct iphdr *iph = ip_hdr(skb);
97
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);
102 }
103
104 int ip_local_out(struct sk_buff *skb)
105 {
106 int err;
107
108 err = __ip_local_out(skb);
109 if (likely(err == 1))
110 err = dst_output(skb);
111
112 return err;
113 }
114 EXPORT_SYMBOL_GPL(ip_local_out);
115
116 static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
117 {
118 int ttl = inet->uc_ttl;
119
120 if (ttl < 0)
121 ttl = ip4_dst_hoplimit(dst);
122 return ttl;
123 }
124
125 /*
126 * Add an ip header to a skbuff and send it out.
127 *
128 */
129 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
130 __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
131 {
132 struct inet_sock *inet = inet_sk(sk);
133 struct rtable *rt = skb_rtable(skb);
134 struct iphdr *iph;
135
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);
152
153 if (opt && opt->opt.optlen) {
154 iph->ihl += opt->opt.optlen>>2;
155 ip_options_build(skb, &opt->opt, daddr, rt, 0);
156 }
157
158 skb->priority = sk->sk_priority;
159 skb->mark = sk->sk_mark;
160
161 /* Send it out. */
162 return ip_local_out(skb);
163 }
164 EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
165
166 static inline int ip_finish_output2(struct sk_buff *skb)
167 {
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;
174
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);
179
180 /* Be paranoid, rather than too clever. */
181 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
182 struct sk_buff *skb2;
183
184 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
185 if (skb2 == NULL) {
186 kfree_skb(skb);
187 return -ENOMEM;
188 }
189 if (skb->sk)
190 skb_set_owner_w(skb2, skb->sk);
191 consume_skb(skb);
192 skb = skb2;
193 }
194
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);
202
203 rcu_read_unlock_bh();
204 return res;
205 }
206 rcu_read_unlock_bh();
207
208 net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
209 __func__);
210 kfree_skb(skb);
211 return -EINVAL;
212 }
213
214 static inline int ip_skb_dst_mtu(struct sk_buff *skb)
215 {
216 struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
217
218 return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
219 skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
220 }
221
222 static int ip_finish_output(struct sk_buff *skb)
223 {
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);
229 }
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);
235 }
236
237 int ip_mc_output(struct sk_buff *skb)
238 {
239 struct sock *sk = skb->sk;
240 struct rtable *rt = skb_rtable(skb);
241 struct net_device *dev = rt->dst.dev;
242
243 /*
244 * If the indicated interface is up and running, send the packet.
245 */
246 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
247
248 skb->dev = dev;
249 skb->protocol = htons(ETH_P_IP);
250
251 /*
252 * Multicasts are looped back for other local users
253 */
254
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.
263
264 This check is duplicated in ip_mr_input at the moment.
265 */
266 &&
267 ((rt->rt_flags & RTCF_LOCAL) ||
268 !(IPCB(skb)->flags & IPSKB_FORWARDED))
269 #endif
270 ) {
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);
276 }
277
278 /* Multicasts with ttl 0 must not go beyond the host */
279
280 if (ip_hdr(skb)->ttl == 0) {
281 kfree_skb(skb);
282 return 0;
283 }
284 }
285
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);
291 }
292
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));
296 }
297
298 int ip_output(struct sk_buff *skb)
299 {
300 struct net_device *dev = skb_dst(skb)->dev;
301
302 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
303
304 skb->dev = dev;
305 skb->protocol = htons(ETH_P_IP);
306
307 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev,
308 ip_finish_output,
309 !(IPCB(skb)->flags & IPSKB_REROUTED));
310 }
311
312 /*
313 * copy saddr and daddr, possibly using 64bit load/stores
314 * Equivalent to :
315 * iph->saddr = fl4->saddr;
316 * iph->daddr = fl4->daddr;
317 */
318 static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
319 {
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));
324 }
325
326 int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
327 {
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;
335
336 /* Skip all of this if the packet is already routed,
337 * f.e. by something like SCTP.
338 */
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;
345
346 /* Make sure we can route this packet. */
347 rt = (struct rtable *)__sk_dst_check(sk, 0);
348 if (rt == NULL) {
349 __be32 daddr;
350
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;
355
356 /* If this fails, retransmit mechanism of transport layer will
357 * keep trying until route appears or the connection times
358 * itself out.
359 */
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);
370 }
371 skb_dst_set_noref(skb, &rt->dst);
372
373 packet_routed:
374 if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
375 goto no_route;
376
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);
389
390 /* Transport layer set skb->h.foo itself. */
391
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);
395 }
396
397 ip_select_ident_more(iph, &rt->dst, sk,
398 (skb_shinfo(skb)->gso_segs ?: 1) - 1);
399
400 skb->priority = sk->sk_priority;
401 skb->mark = sk->sk_mark;
402
403 res = ip_local_out(skb);
404 rcu_read_unlock();
405 return res;
406
407 no_route:
408 rcu_read_unlock();
409 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
410 kfree_skb(skb);
411 return -EHOSTUNREACH;
412 }
413 EXPORT_SYMBOL(ip_queue_xmit);
414
415
416 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
417 {
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;
425
426 /* Copy the flags to each fragment. */
427 IPCB(to)->flags = IPCB(from)->flags;
428
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);
441 }
442
443 /*
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.
448 */
449
450 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
451 {
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;
461
462 dev = rt->dst.dev;
463
464 /*
465 * Point into the IP datagram header.
466 */
467
468 iph = ip_hdr(skb);
469
470 if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) {
471 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
472 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
473 htonl(ip_skb_dst_mtu(skb)));
474 kfree_skb(skb);
475 return -EMSGSIZE;
476 }
477
478 /*
479 * Setup starting values.
480 */
481
482 hlen = iph->ihl * 4;
483 mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */
484 #ifdef CONFIG_BRIDGE_NETFILTER
485 if (skb->nf_bridge)
486 mtu -= nf_bridge_mtu_reduction(skb);
487 #endif
488 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
489
490 /* When frag_list is given, use it. First, check its validity:
491 * some transformers could create wrong frag_list or break existing
492 * one, it is not prohibited. In this case fall back to copying.
493 *
494 * LATER: this step can be merged to real generation of fragments,
495 * we can switch to copy when see the first bad fragment.
496 */
497 if (skb_has_frag_list(skb)) {
498 struct sk_buff *frag, *frag2;
499 int first_len = skb_pagelen(skb);
500
501 if (first_len - hlen > mtu ||
502 ((first_len - hlen) & 7) ||
503 ip_is_fragment(iph) ||
504 skb_cloned(skb))
505 goto slow_path;
506
507 skb_walk_frags(skb, frag) {
508 /* Correct geometry. */
509 if (frag->len > mtu ||
510 ((frag->len & 7) && frag->next) ||
511 skb_headroom(frag) < hlen)
512 goto slow_path_clean;
513
514 /* Partially cloned skb? */
515 if (skb_shared(frag))
516 goto slow_path_clean;
517
518 BUG_ON(frag->sk);
519 if (skb->sk) {
520 frag->sk = skb->sk;
521 frag->destructor = sock_wfree;
522 }
523 skb->truesize -= frag->truesize;
524 }
525
526 /* Everything is OK. Generate! */
527
528 err = 0;
529 offset = 0;
530 frag = skb_shinfo(skb)->frag_list;
531 skb_frag_list_init(skb);
532 skb->data_len = first_len - skb_headlen(skb);
533 skb->len = first_len;
534 iph->tot_len = htons(first_len);
535 iph->frag_off = htons(IP_MF);
536 ip_send_check(iph);
537
538 for (;;) {
539 /* Prepare header of the next frame,
540 * before previous one went down. */
541 if (frag) {
542 frag->ip_summed = CHECKSUM_NONE;
543 skb_reset_transport_header(frag);
544 __skb_push(frag, hlen);
545 skb_reset_network_header(frag);
546 memcpy(skb_network_header(frag), iph, hlen);
547 iph = ip_hdr(frag);
548 iph->tot_len = htons(frag->len);
549 ip_copy_metadata(frag, skb);
550 if (offset == 0)
551 ip_options_fragment(frag);
552 offset += skb->len - hlen;
553 iph->frag_off = htons(offset>>3);
554 if (frag->next != NULL)
555 iph->frag_off |= htons(IP_MF);
556 /* Ready, complete checksum */
557 ip_send_check(iph);
558 }
559
560 err = output(skb);
561
562 if (!err)
563 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
564 if (err || !frag)
565 break;
566
567 skb = frag;
568 frag = skb->next;
569 skb->next = NULL;
570 }
571
572 if (err == 0) {
573 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
574 return 0;
575 }
576
577 while (frag) {
578 skb = frag->next;
579 kfree_skb(frag);
580 frag = skb;
581 }
582 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
583 return err;
584
585 slow_path_clean:
586 skb_walk_frags(skb, frag2) {
587 if (frag2 == frag)
588 break;
589 frag2->sk = NULL;
590 frag2->destructor = NULL;
591 skb->truesize += frag2->truesize;
592 }
593 }
594
595 slow_path:
596 left = skb->len - hlen; /* Space per frame */
597 ptr = hlen; /* Where to start from */
598
599 /* for bridged IP traffic encapsulated inside f.e. a vlan header,
600 * we need to make room for the encapsulating header
601 */
602 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb));
603
604 /*
605 * Fragment the datagram.
606 */
607
608 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
609 not_last_frag = iph->frag_off & htons(IP_MF);
610
611 /*
612 * Keep copying data until we run out.
613 */
614
615 while (left > 0) {
616 len = left;
617 /* IF: it doesn't fit, use 'mtu' - the data space left */
618 if (len > mtu)
619 len = mtu;
620 /* IF: we are not sending up to and including the packet end
621 then align the next start on an eight byte boundary */
622 if (len < left) {
623 len &= ~7;
624 }
625 /*
626 * Allocate buffer.
627 */
628
629 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) {
630 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n");
631 err = -ENOMEM;
632 goto fail;
633 }
634
635 /*
636 * Set up data on packet
637 */
638
639 ip_copy_metadata(skb2, skb);
640 skb_reserve(skb2, ll_rs);
641 skb_put(skb2, len + hlen);
642 skb_reset_network_header(skb2);
643 skb2->transport_header = skb2->network_header + hlen;
644
645 /*
646 * Charge the memory for the fragment to any owner
647 * it might possess
648 */
649
650 if (skb->sk)
651 skb_set_owner_w(skb2, skb->sk);
652
653 /*
654 * Copy the packet header into the new buffer.
655 */
656
657 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
658
659 /*
660 * Copy a block of the IP datagram.
661 */
662 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
663 BUG();
664 left -= len;
665
666 /*
667 * Fill in the new header fields.
668 */
669 iph = ip_hdr(skb2);
670 iph->frag_off = htons((offset >> 3));
671
672 /* ANK: dirty, but effective trick. Upgrade options only if
673 * the segment to be fragmented was THE FIRST (otherwise,
674 * options are already fixed) and make it ONCE
675 * on the initial skb, so that all the following fragments
676 * will inherit fixed options.
677 */
678 if (offset == 0)
679 ip_options_fragment(skb);
680
681 /*
682 * Added AC : If we are fragmenting a fragment that's not the
683 * last fragment then keep MF on each bit
684 */
685 if (left > 0 || not_last_frag)
686 iph->frag_off |= htons(IP_MF);
687 ptr += len;
688 offset += len;
689
690 /*
691 * Put this fragment into the sending queue.
692 */
693 iph->tot_len = htons(len + hlen);
694
695 ip_send_check(iph);
696
697 err = output(skb2);
698 if (err)
699 goto fail;
700
701 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
702 }
703 consume_skb(skb);
704 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
705 return err;
706
707 fail:
708 kfree_skb(skb);
709 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
710 return err;
711 }
712 EXPORT_SYMBOL(ip_fragment);
713
714 int
715 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
716 {
717 struct iovec *iov = from;
718
719 if (skb->ip_summed == CHECKSUM_PARTIAL) {
720 if (memcpy_fromiovecend(to, iov, offset, len) < 0)
721 return -EFAULT;
722 } else {
723 __wsum csum = 0;
724 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
725 return -EFAULT;
726 skb->csum = csum_block_add(skb->csum, csum, odd);
727 }
728 return 0;
729 }
730 EXPORT_SYMBOL(ip_generic_getfrag);
731
732 static inline __wsum
733 csum_page(struct page *page, int offset, int copy)
734 {
735 char *kaddr;
736 __wsum csum;
737 kaddr = kmap(page);
738 csum = csum_partial(kaddr + offset, copy, 0);
739 kunmap(page);
740 return csum;
741 }
742
743 static inline int ip_ufo_append_data(struct sock *sk,
744 struct sk_buff_head *queue,
745 int getfrag(void *from, char *to, int offset, int len,
746 int odd, struct sk_buff *skb),
747 void *from, int length, int hh_len, int fragheaderlen,
748 int transhdrlen, int maxfraglen, unsigned int flags)
749 {
750 struct sk_buff *skb;
751 int err;
752
753 /* There is support for UDP fragmentation offload by network
754 * device, so create one single skb packet containing complete
755 * udp datagram
756 */
757 if ((skb = skb_peek_tail(queue)) == NULL) {
758 skb = sock_alloc_send_skb(sk,
759 hh_len + fragheaderlen + transhdrlen + 20,
760 (flags & MSG_DONTWAIT), &err);
761
762 if (skb == NULL)
763 return err;
764
765 /* reserve space for Hardware header */
766 skb_reserve(skb, hh_len);
767
768 /* create space for UDP/IP header */
769 skb_put(skb, fragheaderlen + transhdrlen);
770
771 /* initialize network header pointer */
772 skb_reset_network_header(skb);
773
774 /* initialize protocol header pointer */
775 skb->transport_header = skb->network_header + fragheaderlen;
776
777 skb->ip_summed = CHECKSUM_PARTIAL;
778 skb->csum = 0;
779
780 /* specify the length of each IP datagram fragment */
781 skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen;
782 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
783 __skb_queue_tail(queue, skb);
784 }
785
786 return skb_append_datato_frags(sk, skb, getfrag, from,
787 (length - transhdrlen));
788 }
789
790 static int __ip_append_data(struct sock *sk,
791 struct flowi4 *fl4,
792 struct sk_buff_head *queue,
793 struct inet_cork *cork,
794 int getfrag(void *from, char *to, int offset,
795 int len, int odd, struct sk_buff *skb),
796 void *from, int length, int transhdrlen,
797 unsigned int flags)
798 {
799 struct inet_sock *inet = inet_sk(sk);
800 struct sk_buff *skb;
801
802 struct ip_options *opt = cork->opt;
803 int hh_len;
804 int exthdrlen;
805 int mtu;
806 int copy;
807 int err;
808 int offset = 0;
809 unsigned int maxfraglen, fragheaderlen;
810 int csummode = CHECKSUM_NONE;
811 struct rtable *rt = (struct rtable *)cork->dst;
812
813 skb = skb_peek_tail(queue);
814
815 exthdrlen = !skb ? rt->dst.header_len : 0;
816 mtu = cork->fragsize;
817
818 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
819
820 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
821 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
822
823 if (cork->length + length > 0xFFFF - fragheaderlen) {
824 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
825 mtu-exthdrlen);
826 return -EMSGSIZE;
827 }
828
829 /*
830 * transhdrlen > 0 means that this is the first fragment and we wish
831 * it won't be fragmented in the future.
832 */
833 if (transhdrlen &&
834 length + fragheaderlen <= mtu &&
835 rt->dst.dev->features & NETIF_F_V4_CSUM &&
836 !exthdrlen)
837 csummode = CHECKSUM_PARTIAL;
838
839 cork->length += length;
840 if (((length > mtu) || (skb && skb_is_gso(skb))) &&
841 (sk->sk_protocol == IPPROTO_UDP) &&
842 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) {
843 err = ip_ufo_append_data(sk, queue, getfrag, from, length,
844 hh_len, fragheaderlen, transhdrlen,
845 maxfraglen, flags);
846 if (err)
847 goto error;
848 return 0;
849 }
850
851 /* So, what's going on in the loop below?
852 *
853 * We use calculated fragment length to generate chained skb,
854 * each of segments is IP fragment ready for sending to network after
855 * adding appropriate IP header.
856 */
857
858 if (!skb)
859 goto alloc_new_skb;
860
861 while (length > 0) {
862 /* Check if the remaining data fits into current packet. */
863 copy = mtu - skb->len;
864 if (copy < length)
865 copy = maxfraglen - skb->len;
866 if (copy <= 0) {
867 char *data;
868 unsigned int datalen;
869 unsigned int fraglen;
870 unsigned int fraggap;
871 unsigned int alloclen;
872 struct sk_buff *skb_prev;
873 alloc_new_skb:
874 skb_prev = skb;
875 if (skb_prev)
876 fraggap = skb_prev->len - maxfraglen;
877 else
878 fraggap = 0;
879
880 /*
881 * If remaining data exceeds the mtu,
882 * we know we need more fragment(s).
883 */
884 datalen = length + fraggap;
885 if (datalen > mtu - fragheaderlen)
886 datalen = maxfraglen - fragheaderlen;
887 fraglen = datalen + fragheaderlen;
888
889 if ((flags & MSG_MORE) &&
890 !(rt->dst.dev->features&NETIF_F_SG))
891 alloclen = mtu;
892 else
893 alloclen = fraglen;
894
895 alloclen += exthdrlen;
896
897 /* The last fragment gets additional space at tail.
898 * Note, with MSG_MORE we overallocate on fragments,
899 * because we have no idea what fragment will be
900 * the last.
901 */
902 if (datalen == length + fraggap)
903 alloclen += rt->dst.trailer_len;
904
905 if (transhdrlen) {
906 skb = sock_alloc_send_skb(sk,
907 alloclen + hh_len + 15,
908 (flags & MSG_DONTWAIT), &err);
909 } else {
910 skb = NULL;
911 if (atomic_read(&sk->sk_wmem_alloc) <=
912 2 * sk->sk_sndbuf)
913 skb = sock_wmalloc(sk,
914 alloclen + hh_len + 15, 1,
915 sk->sk_allocation);
916 if (unlikely(skb == NULL))
917 err = -ENOBUFS;
918 else
919 /* only the initial fragment is
920 time stamped */
921 cork->tx_flags = 0;
922 }
923 if (skb == NULL)
924 goto error;
925
926 /*
927 * Fill in the control structures
928 */
929 skb->ip_summed = csummode;
930 skb->csum = 0;
931 skb_reserve(skb, hh_len);
932 skb_shinfo(skb)->tx_flags = cork->tx_flags;
933
934 /*
935 * Find where to start putting bytes.
936 */
937 data = skb_put(skb, fraglen + exthdrlen);
938 skb_set_network_header(skb, exthdrlen);
939 skb->transport_header = (skb->network_header +
940 fragheaderlen);
941 data += fragheaderlen + exthdrlen;
942
943 if (fraggap) {
944 skb->csum = skb_copy_and_csum_bits(
945 skb_prev, maxfraglen,
946 data + transhdrlen, fraggap, 0);
947 skb_prev->csum = csum_sub(skb_prev->csum,
948 skb->csum);
949 data += fraggap;
950 pskb_trim_unique(skb_prev, maxfraglen);
951 }
952
953 copy = datalen - transhdrlen - fraggap;
954 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
955 err = -EFAULT;
956 kfree_skb(skb);
957 goto error;
958 }
959
960 offset += copy;
961 length -= datalen - fraggap;
962 transhdrlen = 0;
963 exthdrlen = 0;
964 csummode = CHECKSUM_NONE;
965
966 /*
967 * Put the packet on the pending queue.
968 */
969 __skb_queue_tail(queue, skb);
970 continue;
971 }
972
973 if (copy > length)
974 copy = length;
975
976 if (!(rt->dst.dev->features&NETIF_F_SG)) {
977 unsigned int off;
978
979 off = skb->len;
980 if (getfrag(from, skb_put(skb, copy),
981 offset, copy, off, skb) < 0) {
982 __skb_trim(skb, off);
983 err = -EFAULT;
984 goto error;
985 }
986 } else {
987 int i = skb_shinfo(skb)->nr_frags;
988 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
989 struct page *page = cork->page;
990 int off = cork->off;
991 unsigned int left;
992
993 if (page && (left = PAGE_SIZE - off) > 0) {
994 if (copy >= left)
995 copy = left;
996 if (page != skb_frag_page(frag)) {
997 if (i == MAX_SKB_FRAGS) {
998 err = -EMSGSIZE;
999 goto error;
1000 }
1001 skb_fill_page_desc(skb, i, page, off, 0);
1002 skb_frag_ref(skb, i);
1003 frag = &skb_shinfo(skb)->frags[i];
1004 }
1005 } else if (i < MAX_SKB_FRAGS) {
1006 if (copy > PAGE_SIZE)
1007 copy = PAGE_SIZE;
1008 page = alloc_pages(sk->sk_allocation, 0);
1009 if (page == NULL) {
1010 err = -ENOMEM;
1011 goto error;
1012 }
1013 cork->page = page;
1014 cork->off = 0;
1015
1016 skb_fill_page_desc(skb, i, page, 0, 0);
1017 frag = &skb_shinfo(skb)->frags[i];
1018 } else {
1019 err = -EMSGSIZE;
1020 goto error;
1021 }
1022 if (getfrag(from, skb_frag_address(frag)+skb_frag_size(frag),
1023 offset, copy, skb->len, skb) < 0) {
1024 err = -EFAULT;
1025 goto error;
1026 }
1027 cork->off += copy;
1028 skb_frag_size_add(frag, copy);
1029 skb->len += copy;
1030 skb->data_len += copy;
1031 skb->truesize += copy;
1032 atomic_add(copy, &sk->sk_wmem_alloc);
1033 }
1034 offset += copy;
1035 length -= copy;
1036 }
1037
1038 return 0;
1039
1040 error:
1041 cork->length -= length;
1042 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1043 return err;
1044 }
1045
1046 static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1047 struct ipcm_cookie *ipc, struct rtable **rtp)
1048 {
1049 struct inet_sock *inet = inet_sk(sk);
1050 struct ip_options_rcu *opt;
1051 struct rtable *rt;
1052
1053 /*
1054 * setup for corking.
1055 */
1056 opt = ipc->opt;
1057 if (opt) {
1058 if (cork->opt == NULL) {
1059 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1060 sk->sk_allocation);
1061 if (unlikely(cork->opt == NULL))
1062 return -ENOBUFS;
1063 }
1064 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1065 cork->flags |= IPCORK_OPT;
1066 cork->addr = ipc->addr;
1067 }
1068 rt = *rtp;
1069 if (unlikely(!rt))
1070 return -EFAULT;
1071 /*
1072 * We steal reference to this route, caller should not release it
1073 */
1074 *rtp = NULL;
1075 cork->fragsize = inet->pmtudisc == IP_PMTUDISC_PROBE ?
1076 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1077 cork->dst = &rt->dst;
1078 cork->length = 0;
1079 cork->tx_flags = ipc->tx_flags;
1080 cork->page = NULL;
1081 cork->off = 0;
1082
1083 return 0;
1084 }
1085
1086 /*
1087 * ip_append_data() and ip_append_page() can make one large IP datagram
1088 * from many pieces of data. Each pieces will be holded on the socket
1089 * until ip_push_pending_frames() is called. Each piece can be a page
1090 * or non-page data.
1091 *
1092 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1093 * this interface potentially.
1094 *
1095 * LATER: length must be adjusted by pad at tail, when it is required.
1096 */
1097 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1098 int getfrag(void *from, char *to, int offset, int len,
1099 int odd, struct sk_buff *skb),
1100 void *from, int length, int transhdrlen,
1101 struct ipcm_cookie *ipc, struct rtable **rtp,
1102 unsigned int flags)
1103 {
1104 struct inet_sock *inet = inet_sk(sk);
1105 int err;
1106
1107 if (flags&MSG_PROBE)
1108 return 0;
1109
1110 if (skb_queue_empty(&sk->sk_write_queue)) {
1111 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1112 if (err)
1113 return err;
1114 } else {
1115 transhdrlen = 0;
1116 }
1117
1118 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base, getfrag,
1119 from, length, transhdrlen, flags);
1120 }
1121
1122 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1123 int offset, size_t size, int flags)
1124 {
1125 struct inet_sock *inet = inet_sk(sk);
1126 struct sk_buff *skb;
1127 struct rtable *rt;
1128 struct ip_options *opt = NULL;
1129 struct inet_cork *cork;
1130 int hh_len;
1131 int mtu;
1132 int len;
1133 int err;
1134 unsigned int maxfraglen, fragheaderlen, fraggap;
1135
1136 if (inet->hdrincl)
1137 return -EPERM;
1138
1139 if (flags&MSG_PROBE)
1140 return 0;
1141
1142 if (skb_queue_empty(&sk->sk_write_queue))
1143 return -EINVAL;
1144
1145 cork = &inet->cork.base;
1146 rt = (struct rtable *)cork->dst;
1147 if (cork->flags & IPCORK_OPT)
1148 opt = cork->opt;
1149
1150 if (!(rt->dst.dev->features&NETIF_F_SG))
1151 return -EOPNOTSUPP;
1152
1153 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1154 mtu = cork->fragsize;
1155
1156 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1157 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1158
1159 if (cork->length + size > 0xFFFF - fragheaderlen) {
1160 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, mtu);
1161 return -EMSGSIZE;
1162 }
1163
1164 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1165 return -EINVAL;
1166
1167 cork->length += size;
1168 if ((size + skb->len > mtu) &&
1169 (sk->sk_protocol == IPPROTO_UDP) &&
1170 (rt->dst.dev->features & NETIF_F_UFO)) {
1171 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1172 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1173 }
1174
1175
1176 while (size > 0) {
1177 int i;
1178
1179 if (skb_is_gso(skb))
1180 len = size;
1181 else {
1182
1183 /* Check if the remaining data fits into current packet. */
1184 len = mtu - skb->len;
1185 if (len < size)
1186 len = maxfraglen - skb->len;
1187 }
1188 if (len <= 0) {
1189 struct sk_buff *skb_prev;
1190 int alloclen;
1191
1192 skb_prev = skb;
1193 fraggap = skb_prev->len - maxfraglen;
1194
1195 alloclen = fragheaderlen + hh_len + fraggap + 15;
1196 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1197 if (unlikely(!skb)) {
1198 err = -ENOBUFS;
1199 goto error;
1200 }
1201
1202 /*
1203 * Fill in the control structures
1204 */
1205 skb->ip_summed = CHECKSUM_NONE;
1206 skb->csum = 0;
1207 skb_reserve(skb, hh_len);
1208
1209 /*
1210 * Find where to start putting bytes.
1211 */
1212 skb_put(skb, fragheaderlen + fraggap);
1213 skb_reset_network_header(skb);
1214 skb->transport_header = (skb->network_header +
1215 fragheaderlen);
1216 if (fraggap) {
1217 skb->csum = skb_copy_and_csum_bits(skb_prev,
1218 maxfraglen,
1219 skb_transport_header(skb),
1220 fraggap, 0);
1221 skb_prev->csum = csum_sub(skb_prev->csum,
1222 skb->csum);
1223 pskb_trim_unique(skb_prev, maxfraglen);
1224 }
1225
1226 /*
1227 * Put the packet on the pending queue.
1228 */
1229 __skb_queue_tail(&sk->sk_write_queue, skb);
1230 continue;
1231 }
1232
1233 i = skb_shinfo(skb)->nr_frags;
1234 if (len > size)
1235 len = size;
1236 if (skb_can_coalesce(skb, i, page, offset)) {
1237 skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
1238 } else if (i < MAX_SKB_FRAGS) {
1239 get_page(page);
1240 skb_fill_page_desc(skb, i, page, offset, len);
1241 } else {
1242 err = -EMSGSIZE;
1243 goto error;
1244 }
1245
1246 if (skb->ip_summed == CHECKSUM_NONE) {
1247 __wsum csum;
1248 csum = csum_page(page, offset, len);
1249 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1250 }
1251
1252 skb->len += len;
1253 skb->data_len += len;
1254 skb->truesize += len;
1255 atomic_add(len, &sk->sk_wmem_alloc);
1256 offset += len;
1257 size -= len;
1258 }
1259 return 0;
1260
1261 error:
1262 cork->length -= size;
1263 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1264 return err;
1265 }
1266
1267 static void ip_cork_release(struct inet_cork *cork)
1268 {
1269 cork->flags &= ~IPCORK_OPT;
1270 kfree(cork->opt);
1271 cork->opt = NULL;
1272 dst_release(cork->dst);
1273 cork->dst = NULL;
1274 }
1275
1276 /*
1277 * Combined all pending IP fragments on the socket as one IP datagram
1278 * and push them out.
1279 */
1280 struct sk_buff *__ip_make_skb(struct sock *sk,
1281 struct flowi4 *fl4,
1282 struct sk_buff_head *queue,
1283 struct inet_cork *cork)
1284 {
1285 struct sk_buff *skb, *tmp_skb;
1286 struct sk_buff **tail_skb;
1287 struct inet_sock *inet = inet_sk(sk);
1288 struct net *net = sock_net(sk);
1289 struct ip_options *opt = NULL;
1290 struct rtable *rt = (struct rtable *)cork->dst;
1291 struct iphdr *iph;
1292 __be16 df = 0;
1293 __u8 ttl;
1294
1295 if ((skb = __skb_dequeue(queue)) == NULL)
1296 goto out;
1297 tail_skb = &(skb_shinfo(skb)->frag_list);
1298
1299 /* move skb->data to ip header from ext header */
1300 if (skb->data < skb_network_header(skb))
1301 __skb_pull(skb, skb_network_offset(skb));
1302 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1303 __skb_pull(tmp_skb, skb_network_header_len(skb));
1304 *tail_skb = tmp_skb;
1305 tail_skb = &(tmp_skb->next);
1306 skb->len += tmp_skb->len;
1307 skb->data_len += tmp_skb->len;
1308 skb->truesize += tmp_skb->truesize;
1309 tmp_skb->destructor = NULL;
1310 tmp_skb->sk = NULL;
1311 }
1312
1313 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1314 * to fragment the frame generated here. No matter, what transforms
1315 * how transforms change size of the packet, it will come out.
1316 */
1317 if (inet->pmtudisc < IP_PMTUDISC_DO)
1318 skb->local_df = 1;
1319
1320 /* DF bit is set when we want to see DF on outgoing frames.
1321 * If local_df is set too, we still allow to fragment this frame
1322 * locally. */
1323 if (inet->pmtudisc >= IP_PMTUDISC_DO ||
1324 (skb->len <= dst_mtu(&rt->dst) &&
1325 ip_dont_fragment(sk, &rt->dst)))
1326 df = htons(IP_DF);
1327
1328 if (cork->flags & IPCORK_OPT)
1329 opt = cork->opt;
1330
1331 if (rt->rt_type == RTN_MULTICAST)
1332 ttl = inet->mc_ttl;
1333 else
1334 ttl = ip_select_ttl(inet, &rt->dst);
1335
1336 iph = (struct iphdr *)skb->data;
1337 iph->version = 4;
1338 iph->ihl = 5;
1339 iph->tos = inet->tos;
1340 iph->frag_off = df;
1341 iph->ttl = ttl;
1342 iph->protocol = sk->sk_protocol;
1343 ip_copy_addrs(iph, fl4);
1344 ip_select_ident(iph, &rt->dst, sk);
1345
1346 if (opt) {
1347 iph->ihl += opt->optlen>>2;
1348 ip_options_build(skb, opt, cork->addr, rt, 0);
1349 }
1350
1351 skb->priority = sk->sk_priority;
1352 skb->mark = sk->sk_mark;
1353 /*
1354 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1355 * on dst refcount
1356 */
1357 cork->dst = NULL;
1358 skb_dst_set(skb, &rt->dst);
1359
1360 if (iph->protocol == IPPROTO_ICMP)
1361 icmp_out_count(net, ((struct icmphdr *)
1362 skb_transport_header(skb))->type);
1363
1364 ip_cork_release(cork);
1365 out:
1366 return skb;
1367 }
1368
1369 int ip_send_skb(struct net *net, struct sk_buff *skb)
1370 {
1371 int err;
1372
1373 err = ip_local_out(skb);
1374 if (err) {
1375 if (err > 0)
1376 err = net_xmit_errno(err);
1377 if (err)
1378 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1379 }
1380
1381 return err;
1382 }
1383
1384 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
1385 {
1386 struct sk_buff *skb;
1387
1388 skb = ip_finish_skb(sk, fl4);
1389 if (!skb)
1390 return 0;
1391
1392 /* Netfilter gets whole the not fragmented skb. */
1393 return ip_send_skb(sock_net(sk), skb);
1394 }
1395
1396 /*
1397 * Throw away all pending data on the socket.
1398 */
1399 static void __ip_flush_pending_frames(struct sock *sk,
1400 struct sk_buff_head *queue,
1401 struct inet_cork *cork)
1402 {
1403 struct sk_buff *skb;
1404
1405 while ((skb = __skb_dequeue_tail(queue)) != NULL)
1406 kfree_skb(skb);
1407
1408 ip_cork_release(cork);
1409 }
1410
1411 void ip_flush_pending_frames(struct sock *sk)
1412 {
1413 __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1414 }
1415
1416 struct sk_buff *ip_make_skb(struct sock *sk,
1417 struct flowi4 *fl4,
1418 int getfrag(void *from, char *to, int offset,
1419 int len, int odd, struct sk_buff *skb),
1420 void *from, int length, int transhdrlen,
1421 struct ipcm_cookie *ipc, struct rtable **rtp,
1422 unsigned int flags)
1423 {
1424 struct inet_cork cork;
1425 struct sk_buff_head queue;
1426 int err;
1427
1428 if (flags & MSG_PROBE)
1429 return NULL;
1430
1431 __skb_queue_head_init(&queue);
1432
1433 cork.flags = 0;
1434 cork.addr = 0;
1435 cork.opt = NULL;
1436 err = ip_setup_cork(sk, &cork, ipc, rtp);
1437 if (err)
1438 return ERR_PTR(err);
1439
1440 err = __ip_append_data(sk, fl4, &queue, &cork, getfrag,
1441 from, length, transhdrlen, flags);
1442 if (err) {
1443 __ip_flush_pending_frames(sk, &queue, &cork);
1444 return ERR_PTR(err);
1445 }
1446
1447 return __ip_make_skb(sk, fl4, &queue, &cork);
1448 }
1449
1450 /*
1451 * Fetch data from kernel space and fill in checksum if needed.
1452 */
1453 static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1454 int len, int odd, struct sk_buff *skb)
1455 {
1456 __wsum csum;
1457
1458 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1459 skb->csum = csum_block_add(skb->csum, csum, odd);
1460 return 0;
1461 }
1462
1463 /*
1464 * Generic function to send a packet as reply to another packet.
1465 * Used to send some TCP resets/acks so far.
1466 *
1467 * Use a fake percpu inet socket to avoid false sharing and contention.
1468 */
1469 static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
1470 .sk = {
1471 .__sk_common = {
1472 .skc_refcnt = ATOMIC_INIT(1),
1473 },
1474 .sk_wmem_alloc = ATOMIC_INIT(1),
1475 .sk_allocation = GFP_ATOMIC,
1476 .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE),
1477 },
1478 .pmtudisc = IP_PMTUDISC_WANT,
1479 .uc_ttl = -1,
1480 };
1481
1482 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
1483 __be32 saddr, const struct ip_reply_arg *arg,
1484 unsigned int len)
1485 {
1486 struct ip_options_data replyopts;
1487 struct ipcm_cookie ipc;
1488 struct flowi4 fl4;
1489 struct rtable *rt = skb_rtable(skb);
1490 struct sk_buff *nskb;
1491 struct sock *sk;
1492 struct inet_sock *inet;
1493
1494 if (ip_options_echo(&replyopts.opt.opt, skb))
1495 return;
1496
1497 ipc.addr = daddr;
1498 ipc.opt = NULL;
1499 ipc.tx_flags = 0;
1500
1501 if (replyopts.opt.opt.optlen) {
1502 ipc.opt = &replyopts.opt;
1503
1504 if (replyopts.opt.opt.srr)
1505 daddr = replyopts.opt.opt.faddr;
1506 }
1507
1508 flowi4_init_output(&fl4, arg->bound_dev_if, 0,
1509 RT_TOS(arg->tos),
1510 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1511 ip_reply_arg_flowi_flags(arg),
1512 daddr, saddr,
1513 tcp_hdr(skb)->source, tcp_hdr(skb)->dest);
1514 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1515 rt = ip_route_output_key(net, &fl4);
1516 if (IS_ERR(rt))
1517 return;
1518
1519 inet = &get_cpu_var(unicast_sock);
1520
1521 inet->tos = arg->tos;
1522 sk = &inet->sk;
1523 sk->sk_priority = skb->priority;
1524 sk->sk_protocol = ip_hdr(skb)->protocol;
1525 sk->sk_bound_dev_if = arg->bound_dev_if;
1526 sock_net_set(sk, net);
1527 __skb_queue_head_init(&sk->sk_write_queue);
1528 sk->sk_sndbuf = sysctl_wmem_default;
1529 ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
1530 &ipc, &rt, MSG_DONTWAIT);
1531 nskb = skb_peek(&sk->sk_write_queue);
1532 if (nskb) {
1533 if (arg->csumoffset >= 0)
1534 *((__sum16 *)skb_transport_header(nskb) +
1535 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1536 arg->csum));
1537 nskb->ip_summed = CHECKSUM_NONE;
1538 skb_orphan(nskb);
1539 skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb));
1540 ip_push_pending_frames(sk, &fl4);
1541 }
1542
1543 put_cpu_var(unicast_sock);
1544
1545 ip_rt_put(rt);
1546 }
1547
1548 void __init ip_init(void)
1549 {
1550 ip_rt_init();
1551 inet_initpeers();
1552
1553 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
1554 igmp_mc_proc_init();
1555 #endif
1556 }
Linux ARM platform port for MOXA ART SoC