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import PULS_20160108
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ipv4 / ip_output.c
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 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(skb, 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_segs(skb, sk, skb_shinfo(skb)->gso_segs ?: 1);
398
399 skb->priority = sk->sk_priority;
400 skb->mark = sk->sk_mark;
401
402 res = ip_local_out(skb);
403 rcu_read_unlock();
404 return res;
405
406 no_route:
407 rcu_read_unlock();
408 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
409 kfree_skb(skb);
410 return -EHOSTUNREACH;
411 }
412 EXPORT_SYMBOL(ip_queue_xmit);
413
414
415 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
416 {
417 to->pkt_type = from->pkt_type;
418 to->priority = from->priority;
419 to->protocol = from->protocol;
420 skb_dst_drop(to);
421 skb_dst_copy(to, from);
422 to->dev = from->dev;
423 to->mark = from->mark;
424
425 /* Copy the flags to each fragment. */
426 IPCB(to)->flags = IPCB(from)->flags;
427
428 #ifdef CONFIG_NET_SCHED
429 to->tc_index = from->tc_index;
430 #endif
431 nf_copy(to, from);
432 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
433 to->nf_trace = from->nf_trace;
434 #endif
435 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
436 to->ipvs_property = from->ipvs_property;
437 #endif
438 skb_copy_secmark(to, from);
439 }
440
441 /*
442 * This IP datagram is too large to be sent in one piece. Break it up into
443 * smaller pieces (each of size equal to IP header plus
444 * a block of the data of the original IP data part) that will yet fit in a
445 * single device frame, and queue such a frame for sending.
446 */
447
448 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
449 {
450 struct iphdr *iph;
451 int ptr;
452 struct net_device *dev;
453 struct sk_buff *skb2;
454 unsigned int mtu, hlen, left, len, ll_rs;
455 int offset;
456 __be16 not_last_frag;
457 struct rtable *rt = skb_rtable(skb);
458 int err = 0;
459
460 dev = rt->dst.dev;
461
462 /*
463 * Point into the IP datagram header.
464 */
465
466 iph = ip_hdr(skb);
467
468 if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->local_df) ||
469 (IPCB(skb)->frag_max_size &&
470 IPCB(skb)->frag_max_size > dst_mtu(&rt->dst)))) {
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 /* for offloaded checksums cleanup checksum before fragmentation */
597 if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb))
598 goto fail;
599 iph = ip_hdr(skb);
600
601 left = skb->len - hlen; /* Space per frame */
602 ptr = hlen; /* Where to start from */
603
604 /* for bridged IP traffic encapsulated inside f.e. a vlan header,
605 * we need to make room for the encapsulating header
606 */
607 ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb));
608
609 /*
610 * Fragment the datagram.
611 */
612
613 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
614 not_last_frag = iph->frag_off & htons(IP_MF);
615
616 /*
617 * Keep copying data until we run out.
618 */
619
620 while (left > 0) {
621 len = left;
622 /* IF: it doesn't fit, use 'mtu' - the data space left */
623 if (len > mtu)
624 len = mtu;
625 /* IF: we are not sending up to and including the packet end
626 then align the next start on an eight byte boundary */
627 if (len < left) {
628 len &= ~7;
629 }
630 /*
631 * Allocate buffer.
632 */
633
634 if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) {
635 NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n");
636 err = -ENOMEM;
637 goto fail;
638 }
639
640 /*
641 * Set up data on packet
642 */
643
644 ip_copy_metadata(skb2, skb);
645 skb_reserve(skb2, ll_rs);
646 skb_put(skb2, len + hlen);
647 skb_reset_network_header(skb2);
648 skb2->transport_header = skb2->network_header + hlen;
649
650 /*
651 * Charge the memory for the fragment to any owner
652 * it might possess
653 */
654
655 if (skb->sk)
656 skb_set_owner_w(skb2, skb->sk);
657
658 /*
659 * Copy the packet header into the new buffer.
660 */
661
662 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
663
664 /*
665 * Copy a block of the IP datagram.
666 */
667 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
668 BUG();
669 left -= len;
670
671 /*
672 * Fill in the new header fields.
673 */
674 iph = ip_hdr(skb2);
675 iph->frag_off = htons((offset >> 3));
676
677 /* ANK: dirty, but effective trick. Upgrade options only if
678 * the segment to be fragmented was THE FIRST (otherwise,
679 * options are already fixed) and make it ONCE
680 * on the initial skb, so that all the following fragments
681 * will inherit fixed options.
682 */
683 if (offset == 0)
684 ip_options_fragment(skb);
685
686 /*
687 * Added AC : If we are fragmenting a fragment that's not the
688 * last fragment then keep MF on each bit
689 */
690 if (left > 0 || not_last_frag)
691 iph->frag_off |= htons(IP_MF);
692 ptr += len;
693 offset += len;
694
695 /*
696 * Put this fragment into the sending queue.
697 */
698 iph->tot_len = htons(len + hlen);
699
700 ip_send_check(iph);
701
702 err = output(skb2);
703 if (err)
704 goto fail;
705
706 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
707 }
708 consume_skb(skb);
709 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
710 return err;
711
712 fail:
713 kfree_skb(skb);
714 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
715 return err;
716 }
717 EXPORT_SYMBOL(ip_fragment);
718
719 int
720 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
721 {
722 struct iovec *iov = from;
723
724 if (skb->ip_summed == CHECKSUM_PARTIAL) {
725 if (memcpy_fromiovecend(to, iov, offset, len) < 0)
726 return -EFAULT;
727 } else {
728 __wsum csum = 0;
729 if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
730 return -EFAULT;
731 skb->csum = csum_block_add(skb->csum, csum, odd);
732 }
733 return 0;
734 }
735 EXPORT_SYMBOL(ip_generic_getfrag);
736
737 static inline __wsum
738 csum_page(struct page *page, int offset, int copy)
739 {
740 char *kaddr;
741 __wsum csum;
742 kaddr = kmap(page);
743 csum = csum_partial(kaddr + offset, copy, 0);
744 kunmap(page);
745 return csum;
746 }
747
748 static inline int ip_ufo_append_data(struct sock *sk,
749 struct sk_buff_head *queue,
750 int getfrag(void *from, char *to, int offset, int len,
751 int odd, struct sk_buff *skb),
752 void *from, int length, int hh_len, int fragheaderlen,
753 int transhdrlen, int maxfraglen, unsigned int flags)
754 {
755 struct sk_buff *skb;
756 int err;
757
758 /* There is support for UDP fragmentation offload by network
759 * device, so create one single skb packet containing complete
760 * udp datagram
761 */
762 if ((skb = skb_peek_tail(queue)) == NULL) {
763 skb = sock_alloc_send_skb(sk,
764 hh_len + fragheaderlen + transhdrlen + 20,
765 (flags & MSG_DONTWAIT), &err);
766
767 if (skb == NULL)
768 return err;
769
770 /* reserve space for Hardware header */
771 skb_reserve(skb, hh_len);
772
773 /* create space for UDP/IP header */
774 skb_put(skb, fragheaderlen + transhdrlen);
775
776 /* initialize network header pointer */
777 skb_reset_network_header(skb);
778
779 /* initialize protocol header pointer */
780 skb->transport_header = skb->network_header + fragheaderlen;
781
782 skb->ip_summed = CHECKSUM_PARTIAL;
783 skb->csum = 0;
784
785 /* specify the length of each IP datagram fragment */
786 skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen;
787 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
788 __skb_queue_tail(queue, skb);
789 }
790
791 return skb_append_datato_frags(sk, skb, getfrag, from,
792 (length - transhdrlen));
793 }
794
795 static int __ip_append_data(struct sock *sk,
796 struct flowi4 *fl4,
797 struct sk_buff_head *queue,
798 struct inet_cork *cork,
799 struct page_frag *pfrag,
800 int getfrag(void *from, char *to, int offset,
801 int len, int odd, struct sk_buff *skb),
802 void *from, int length, int transhdrlen,
803 unsigned int flags)
804 {
805 struct inet_sock *inet = inet_sk(sk);
806 struct sk_buff *skb;
807
808 struct ip_options *opt = cork->opt;
809 int hh_len;
810 int exthdrlen;
811 int mtu;
812 int copy;
813 int err;
814 int offset = 0;
815 unsigned int maxfraglen, fragheaderlen;
816 int csummode = CHECKSUM_NONE;
817 struct rtable *rt = (struct rtable *)cork->dst;
818
819 skb = skb_peek_tail(queue);
820
821 exthdrlen = !skb ? rt->dst.header_len : 0;
822 mtu = cork->fragsize;
823
824 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
825
826 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
827 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
828
829 if (cork->length + length > 0xFFFF - fragheaderlen) {
830 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
831 mtu-exthdrlen);
832 return -EMSGSIZE;
833 }
834
835 /*
836 * transhdrlen > 0 means that this is the first fragment and we wish
837 * it won't be fragmented in the future.
838 */
839 if (transhdrlen &&
840 length + fragheaderlen <= mtu &&
841 rt->dst.dev->features & NETIF_F_V4_CSUM &&
842 !exthdrlen)
843 csummode = CHECKSUM_PARTIAL;
844
845 cork->length += length;
846 if (((length > mtu) || (skb && skb_has_frags(skb))) &&
847 (sk->sk_protocol == IPPROTO_UDP) &&
848 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) {
849 err = ip_ufo_append_data(sk, queue, getfrag, from, length,
850 hh_len, fragheaderlen, transhdrlen,
851 maxfraglen, flags);
852 if (err)
853 goto error;
854 return 0;
855 }
856
857 /* So, what's going on in the loop below?
858 *
859 * We use calculated fragment length to generate chained skb,
860 * each of segments is IP fragment ready for sending to network after
861 * adding appropriate IP header.
862 */
863
864 if (!skb)
865 goto alloc_new_skb;
866
867 while (length > 0) {
868 /* Check if the remaining data fits into current packet. */
869 copy = mtu - skb->len;
870 if (copy < length)
871 copy = maxfraglen - skb->len;
872 if (copy <= 0) {
873 char *data;
874 unsigned int datalen;
875 unsigned int fraglen;
876 unsigned int fraggap;
877 unsigned int alloclen;
878 struct sk_buff *skb_prev;
879 alloc_new_skb:
880 skb_prev = skb;
881 if (skb_prev)
882 fraggap = skb_prev->len - maxfraglen;
883 else
884 fraggap = 0;
885
886 /*
887 * If remaining data exceeds the mtu,
888 * we know we need more fragment(s).
889 */
890 datalen = length + fraggap;
891 if (datalen > mtu - fragheaderlen)
892 datalen = maxfraglen - fragheaderlen;
893 fraglen = datalen + fragheaderlen;
894
895 if ((flags & MSG_MORE) &&
896 !(rt->dst.dev->features&NETIF_F_SG))
897 alloclen = mtu;
898 else
899 alloclen = fraglen;
900
901 alloclen += exthdrlen;
902
903 /* The last fragment gets additional space at tail.
904 * Note, with MSG_MORE we overallocate on fragments,
905 * because we have no idea what fragment will be
906 * the last.
907 */
908 if (datalen == length + fraggap)
909 alloclen += rt->dst.trailer_len;
910
911 if (transhdrlen) {
912 skb = sock_alloc_send_skb(sk,
913 alloclen + hh_len + 15,
914 (flags & MSG_DONTWAIT), &err);
915 } else {
916 skb = NULL;
917 if (atomic_read(&sk->sk_wmem_alloc) <=
918 2 * sk->sk_sndbuf)
919 skb = sock_wmalloc(sk,
920 alloclen + hh_len + 15, 1,
921 sk->sk_allocation);
922 if (unlikely(skb == NULL))
923 err = -ENOBUFS;
924 else
925 /* only the initial fragment is
926 time stamped */
927 cork->tx_flags = 0;
928 }
929 if (skb == NULL)
930 goto error;
931
932 /*
933 * Fill in the control structures
934 */
935 skb->ip_summed = csummode;
936 skb->csum = 0;
937 skb_reserve(skb, hh_len);
938 skb_shinfo(skb)->tx_flags = cork->tx_flags;
939
940 /*
941 * Find where to start putting bytes.
942 */
943 data = skb_put(skb, fraglen + exthdrlen);
944 skb_set_network_header(skb, exthdrlen);
945 skb->transport_header = (skb->network_header +
946 fragheaderlen);
947 data += fragheaderlen + exthdrlen;
948
949 if (fraggap) {
950 skb->csum = skb_copy_and_csum_bits(
951 skb_prev, maxfraglen,
952 data + transhdrlen, fraggap, 0);
953 skb_prev->csum = csum_sub(skb_prev->csum,
954 skb->csum);
955 data += fraggap;
956 pskb_trim_unique(skb_prev, maxfraglen);
957 }
958
959 copy = datalen - transhdrlen - fraggap;
960 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
961 err = -EFAULT;
962 kfree_skb(skb);
963 goto error;
964 }
965
966 offset += copy;
967 length -= datalen - fraggap;
968 transhdrlen = 0;
969 exthdrlen = 0;
970 csummode = CHECKSUM_NONE;
971
972 /*
973 * Put the packet on the pending queue.
974 */
975 __skb_queue_tail(queue, skb);
976 continue;
977 }
978
979 if (copy > length)
980 copy = length;
981
982 if (!(rt->dst.dev->features&NETIF_F_SG)) {
983 unsigned int off;
984
985 off = skb->len;
986 if (getfrag(from, skb_put(skb, copy),
987 offset, copy, off, skb) < 0) {
988 __skb_trim(skb, off);
989 err = -EFAULT;
990 goto error;
991 }
992 } else {
993 int i = skb_shinfo(skb)->nr_frags;
994
995 err = -ENOMEM;
996 if (!sk_page_frag_refill(sk, pfrag))
997 goto error;
998
999 if (!skb_can_coalesce(skb, i, pfrag->page,
1000 pfrag->offset)) {
1001 err = -EMSGSIZE;
1002 if (i == MAX_SKB_FRAGS)
1003 goto error;
1004
1005 __skb_fill_page_desc(skb, i, pfrag->page,
1006 pfrag->offset, 0);
1007 skb_shinfo(skb)->nr_frags = ++i;
1008 get_page(pfrag->page);
1009 }
1010 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1011 if (getfrag(from,
1012 page_address(pfrag->page) + pfrag->offset,
1013 offset, copy, skb->len, skb) < 0)
1014 goto error_efault;
1015
1016 pfrag->offset += copy;
1017 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1018 skb->len += copy;
1019 skb->data_len += copy;
1020 skb->truesize += copy;
1021 atomic_add(copy, &sk->sk_wmem_alloc);
1022 }
1023 offset += copy;
1024 length -= copy;
1025 }
1026
1027 return 0;
1028
1029 error_efault:
1030 err = -EFAULT;
1031 error:
1032 cork->length -= length;
1033 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1034 return err;
1035 }
1036
1037 static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1038 struct ipcm_cookie *ipc, struct rtable **rtp)
1039 {
1040 struct inet_sock *inet = inet_sk(sk);
1041 struct ip_options_rcu *opt;
1042 struct rtable *rt;
1043
1044 /*
1045 * setup for corking.
1046 */
1047 opt = ipc->opt;
1048 if (opt) {
1049 if (cork->opt == NULL) {
1050 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1051 sk->sk_allocation);
1052 if (unlikely(cork->opt == NULL))
1053 return -ENOBUFS;
1054 }
1055 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1056 cork->flags |= IPCORK_OPT;
1057 cork->addr = ipc->addr;
1058 }
1059 rt = *rtp;
1060 if (unlikely(!rt))
1061 return -EFAULT;
1062 /*
1063 * We steal reference to this route, caller should not release it
1064 */
1065 *rtp = NULL;
1066 cork->fragsize = inet->pmtudisc == IP_PMTUDISC_PROBE ?
1067 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1068 cork->dst = &rt->dst;
1069 cork->length = 0;
1070 cork->tx_flags = ipc->tx_flags;
1071
1072 return 0;
1073 }
1074
1075 /*
1076 * ip_append_data() and ip_append_page() can make one large IP datagram
1077 * from many pieces of data. Each pieces will be holded on the socket
1078 * until ip_push_pending_frames() is called. Each piece can be a page
1079 * or non-page data.
1080 *
1081 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1082 * this interface potentially.
1083 *
1084 * LATER: length must be adjusted by pad at tail, when it is required.
1085 */
1086 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1087 int getfrag(void *from, char *to, int offset, int len,
1088 int odd, struct sk_buff *skb),
1089 void *from, int length, int transhdrlen,
1090 struct ipcm_cookie *ipc, struct rtable **rtp,
1091 unsigned int flags)
1092 {
1093 struct inet_sock *inet = inet_sk(sk);
1094 int err;
1095
1096 if (flags&MSG_PROBE)
1097 return 0;
1098
1099 if (skb_queue_empty(&sk->sk_write_queue)) {
1100 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1101 if (err)
1102 return err;
1103 } else {
1104 transhdrlen = 0;
1105 }
1106
1107 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
1108 sk_page_frag(sk), getfrag,
1109 from, length, transhdrlen, flags);
1110 }
1111
1112 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1113 int offset, size_t size, int flags)
1114 {
1115 struct inet_sock *inet = inet_sk(sk);
1116 struct sk_buff *skb;
1117 struct rtable *rt;
1118 struct ip_options *opt = NULL;
1119 struct inet_cork *cork;
1120 int hh_len;
1121 int mtu;
1122 int len;
1123 int err;
1124 unsigned int maxfraglen, fragheaderlen, fraggap;
1125
1126 if (inet->hdrincl)
1127 return -EPERM;
1128
1129 if (flags&MSG_PROBE)
1130 return 0;
1131
1132 if (skb_queue_empty(&sk->sk_write_queue))
1133 return -EINVAL;
1134
1135 cork = &inet->cork.base;
1136 rt = (struct rtable *)cork->dst;
1137 if (cork->flags & IPCORK_OPT)
1138 opt = cork->opt;
1139
1140 if (!(rt->dst.dev->features&NETIF_F_SG))
1141 return -EOPNOTSUPP;
1142
1143 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1144 mtu = cork->fragsize;
1145
1146 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1147 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1148
1149 if (cork->length + size > 0xFFFF - fragheaderlen) {
1150 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, mtu);
1151 return -EMSGSIZE;
1152 }
1153
1154 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1155 return -EINVAL;
1156
1157 cork->length += size;
1158 if ((size + skb->len > mtu) &&
1159 (sk->sk_protocol == IPPROTO_UDP) &&
1160 (rt->dst.dev->features & NETIF_F_UFO)) {
1161 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1162 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1163 }
1164
1165
1166 while (size > 0) {
1167 int i;
1168
1169 if (skb_is_gso(skb))
1170 len = size;
1171 else {
1172
1173 /* Check if the remaining data fits into current packet. */
1174 len = mtu - skb->len;
1175 if (len < size)
1176 len = maxfraglen - skb->len;
1177 }
1178 if (len <= 0) {
1179 struct sk_buff *skb_prev;
1180 int alloclen;
1181
1182 skb_prev = skb;
1183 fraggap = skb_prev->len - maxfraglen;
1184
1185 alloclen = fragheaderlen + hh_len + fraggap + 15;
1186 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1187 if (unlikely(!skb)) {
1188 err = -ENOBUFS;
1189 goto error;
1190 }
1191
1192 /*
1193 * Fill in the control structures
1194 */
1195 skb->ip_summed = CHECKSUM_NONE;
1196 skb->csum = 0;
1197 skb_reserve(skb, hh_len);
1198
1199 /*
1200 * Find where to start putting bytes.
1201 */
1202 skb_put(skb, fragheaderlen + fraggap);
1203 skb_reset_network_header(skb);
1204 skb->transport_header = (skb->network_header +
1205 fragheaderlen);
1206 if (fraggap) {
1207 skb->csum = skb_copy_and_csum_bits(skb_prev,
1208 maxfraglen,
1209 skb_transport_header(skb),
1210 fraggap, 0);
1211 skb_prev->csum = csum_sub(skb_prev->csum,
1212 skb->csum);
1213 pskb_trim_unique(skb_prev, maxfraglen);
1214 }
1215
1216 /*
1217 * Put the packet on the pending queue.
1218 */
1219 __skb_queue_tail(&sk->sk_write_queue, skb);
1220 continue;
1221 }
1222
1223 i = skb_shinfo(skb)->nr_frags;
1224 if (len > size)
1225 len = size;
1226 if (skb_can_coalesce(skb, i, page, offset)) {
1227 skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
1228 } else if (i < MAX_SKB_FRAGS) {
1229 get_page(page);
1230 skb_fill_page_desc(skb, i, page, offset, len);
1231 } else {
1232 err = -EMSGSIZE;
1233 goto error;
1234 }
1235
1236 if (skb->ip_summed == CHECKSUM_NONE) {
1237 __wsum csum;
1238 csum = csum_page(page, offset, len);
1239 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1240 }
1241
1242 skb->len += len;
1243 skb->data_len += len;
1244 skb->truesize += len;
1245 atomic_add(len, &sk->sk_wmem_alloc);
1246 offset += len;
1247 size -= len;
1248 }
1249 return 0;
1250
1251 error:
1252 cork->length -= size;
1253 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1254 return err;
1255 }
1256
1257 static void ip_cork_release(struct inet_cork *cork)
1258 {
1259 cork->flags &= ~IPCORK_OPT;
1260 kfree(cork->opt);
1261 cork->opt = NULL;
1262 dst_release(cork->dst);
1263 cork->dst = NULL;
1264 }
1265
1266 /*
1267 * Combined all pending IP fragments on the socket as one IP datagram
1268 * and push them out.
1269 */
1270 struct sk_buff *__ip_make_skb(struct sock *sk,
1271 struct flowi4 *fl4,
1272 struct sk_buff_head *queue,
1273 struct inet_cork *cork)
1274 {
1275 struct sk_buff *skb, *tmp_skb;
1276 struct sk_buff **tail_skb;
1277 struct inet_sock *inet = inet_sk(sk);
1278 struct net *net = sock_net(sk);
1279 struct ip_options *opt = NULL;
1280 struct rtable *rt = (struct rtable *)cork->dst;
1281 struct iphdr *iph;
1282 __be16 df = 0;
1283 __u8 ttl;
1284
1285 if ((skb = __skb_dequeue(queue)) == NULL)
1286 goto out;
1287 tail_skb = &(skb_shinfo(skb)->frag_list);
1288
1289 /* move skb->data to ip header from ext header */
1290 if (skb->data < skb_network_header(skb))
1291 __skb_pull(skb, skb_network_offset(skb));
1292 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1293 __skb_pull(tmp_skb, skb_network_header_len(skb));
1294 *tail_skb = tmp_skb;
1295 tail_skb = &(tmp_skb->next);
1296 skb->len += tmp_skb->len;
1297 skb->data_len += tmp_skb->len;
1298 skb->truesize += tmp_skb->truesize;
1299 tmp_skb->destructor = NULL;
1300 tmp_skb->sk = NULL;
1301 }
1302
1303 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1304 * to fragment the frame generated here. No matter, what transforms
1305 * how transforms change size of the packet, it will come out.
1306 */
1307 if (inet->pmtudisc < IP_PMTUDISC_DO)
1308 skb->local_df = 1;
1309
1310 /* DF bit is set when we want to see DF on outgoing frames.
1311 * If local_df is set too, we still allow to fragment this frame
1312 * locally. */
1313 if (inet->pmtudisc >= IP_PMTUDISC_DO ||
1314 (skb->len <= dst_mtu(&rt->dst) &&
1315 ip_dont_fragment(sk, &rt->dst)))
1316 df = htons(IP_DF);
1317
1318 if (cork->flags & IPCORK_OPT)
1319 opt = cork->opt;
1320
1321 if (rt->rt_type == RTN_MULTICAST)
1322 ttl = inet->mc_ttl;
1323 else
1324 ttl = ip_select_ttl(inet, &rt->dst);
1325
1326 iph = ip_hdr(skb);
1327 iph->version = 4;
1328 iph->ihl = 5;
1329 iph->tos = inet->tos;
1330 iph->frag_off = df;
1331 iph->ttl = ttl;
1332 iph->protocol = sk->sk_protocol;
1333 ip_copy_addrs(iph, fl4);
1334 ip_select_ident(skb, sk);
1335
1336 if (opt) {
1337 iph->ihl += opt->optlen>>2;
1338 ip_options_build(skb, opt, cork->addr, rt, 0);
1339 }
1340
1341 skb->priority = sk->sk_priority;
1342 skb->mark = sk->sk_mark;
1343 /*
1344 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1345 * on dst refcount
1346 */
1347 cork->dst = NULL;
1348 skb_dst_set(skb, &rt->dst);
1349
1350 if (iph->protocol == IPPROTO_ICMP)
1351 icmp_out_count(net, ((struct icmphdr *)
1352 skb_transport_header(skb))->type);
1353
1354 ip_cork_release(cork);
1355 out:
1356 return skb;
1357 }
1358
1359 int ip_send_skb(struct net *net, struct sk_buff *skb)
1360 {
1361 int err;
1362
1363 err = ip_local_out(skb);
1364 if (err) {
1365 if (err > 0)
1366 err = net_xmit_errno(err);
1367 if (err)
1368 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1369 }
1370
1371 return err;
1372 }
1373
1374 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
1375 {
1376 struct sk_buff *skb;
1377
1378 skb = ip_finish_skb(sk, fl4);
1379 if (!skb)
1380 return 0;
1381
1382 /* Netfilter gets whole the not fragmented skb. */
1383 return ip_send_skb(sock_net(sk), skb);
1384 }
1385
1386 /*
1387 * Throw away all pending data on the socket.
1388 */
1389 static void __ip_flush_pending_frames(struct sock *sk,
1390 struct sk_buff_head *queue,
1391 struct inet_cork *cork)
1392 {
1393 struct sk_buff *skb;
1394
1395 while ((skb = __skb_dequeue_tail(queue)) != NULL)
1396 kfree_skb(skb);
1397
1398 ip_cork_release(cork);
1399 }
1400
1401 void ip_flush_pending_frames(struct sock *sk)
1402 {
1403 __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1404 }
1405
1406 struct sk_buff *ip_make_skb(struct sock *sk,
1407 struct flowi4 *fl4,
1408 int getfrag(void *from, char *to, int offset,
1409 int len, int odd, struct sk_buff *skb),
1410 void *from, int length, int transhdrlen,
1411 struct ipcm_cookie *ipc, struct rtable **rtp,
1412 unsigned int flags)
1413 {
1414 struct inet_cork cork;
1415 struct sk_buff_head queue;
1416 int err;
1417
1418 if (flags & MSG_PROBE)
1419 return NULL;
1420
1421 __skb_queue_head_init(&queue);
1422
1423 cork.flags = 0;
1424 cork.addr = 0;
1425 cork.opt = NULL;
1426 err = ip_setup_cork(sk, &cork, ipc, rtp);
1427 if (err)
1428 return ERR_PTR(err);
1429
1430 err = __ip_append_data(sk, fl4, &queue, &cork,
1431 &current->task_frag, getfrag,
1432 from, length, transhdrlen, flags);
1433 if (err) {
1434 __ip_flush_pending_frames(sk, &queue, &cork);
1435 return ERR_PTR(err);
1436 }
1437
1438 return __ip_make_skb(sk, fl4, &queue, &cork);
1439 }
1440
1441 /*
1442 * Fetch data from kernel space and fill in checksum if needed.
1443 */
1444 static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1445 int len, int odd, struct sk_buff *skb)
1446 {
1447 __wsum csum;
1448
1449 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1450 skb->csum = csum_block_add(skb->csum, csum, odd);
1451 return 0;
1452 }
1453
1454 /*
1455 * Generic function to send a packet as reply to another packet.
1456 * Used to send some TCP resets/acks so far.
1457 *
1458 * Use a fake percpu inet socket to avoid false sharing and contention.
1459 */
1460 static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
1461 .sk = {
1462 .__sk_common = {
1463 .skc_refcnt = ATOMIC_INIT(1),
1464 },
1465 .sk_wmem_alloc = ATOMIC_INIT(1),
1466 .sk_allocation = GFP_ATOMIC,
1467 .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE),
1468 },
1469 .pmtudisc = IP_PMTUDISC_WANT,
1470 .uc_ttl = -1,
1471 };
1472
1473 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
1474 __be32 saddr, const struct ip_reply_arg *arg,
1475 unsigned int len)
1476 {
1477 struct ip_options_data replyopts;
1478 struct ipcm_cookie ipc;
1479 struct flowi4 fl4;
1480 struct rtable *rt = skb_rtable(skb);
1481 struct sk_buff *nskb;
1482 struct sock *sk;
1483 struct inet_sock *inet;
1484
1485 if (ip_options_echo(&replyopts.opt.opt, skb))
1486 return;
1487
1488 ipc.addr = daddr;
1489 ipc.opt = NULL;
1490 ipc.tx_flags = 0;
1491
1492 if (replyopts.opt.opt.optlen) {
1493 ipc.opt = &replyopts.opt;
1494
1495 if (replyopts.opt.opt.srr)
1496 daddr = replyopts.opt.opt.faddr;
1497 }
1498
1499 flowi4_init_output(&fl4, arg->bound_dev_if,
1500 IP4_REPLY_MARK(net, skb->mark),
1501 RT_TOS(arg->tos),
1502 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1503 ip_reply_arg_flowi_flags(arg),
1504 daddr, saddr,
1505 tcp_hdr(skb)->source, tcp_hdr(skb)->dest,
1506 arg->uid);
1507 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1508 rt = ip_route_output_key(net, &fl4);
1509 if (IS_ERR(rt))
1510 return;
1511
1512 inet = &get_cpu_var(unicast_sock);
1513
1514 inet->tos = arg->tos;
1515 sk = &inet->sk;
1516 sk->sk_priority = skb->priority;
1517 sk->sk_protocol = ip_hdr(skb)->protocol;
1518 sk->sk_bound_dev_if = arg->bound_dev_if;
1519 sock_net_set(sk, net);
1520 __skb_queue_head_init(&sk->sk_write_queue);
1521 sk->sk_sndbuf = sysctl_wmem_default;
1522 ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
1523 &ipc, &rt, MSG_DONTWAIT);
1524 nskb = skb_peek(&sk->sk_write_queue);
1525 if (nskb) {
1526 if (arg->csumoffset >= 0)
1527 *((__sum16 *)skb_transport_header(nskb) +
1528 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1529 arg->csum));
1530 nskb->ip_summed = CHECKSUM_NONE;
1531 skb_orphan(nskb);
1532 skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb));
1533 ip_push_pending_frames(sk, &fl4);
1534 }
1535
1536 put_cpu_var(unicast_sock);
1537
1538 ip_rt_put(rt);
1539 }
1540
1541 void __init ip_init(void)
1542 {
1543 ip_rt_init();
1544 inet_initpeers();
1545
1546 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
1547 igmp_mc_proc_init();
1548 #endif
1549 }
kernel source for telekom puls (alcatel/mediatek)