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fix a kmap leak in virtio_console
[linux/fpc-iii.git] / net / ipv4 / ip_output.c
blob8971780aec7c5fadb4223c0391b05aa9c881ba34
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, &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 int ip_finish_output(struct sk_buff *skb)
215 {
216 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
217 /* Policy lookup after SNAT yielded a new policy */
218 if (skb_dst(skb)->xfrm != NULL) {
219 IPCB(skb)->flags |= IPSKB_REROUTED;
220 return dst_output(skb);
221 }
222 #endif
223 if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb))
224 return ip_fragment(skb, ip_finish_output2);
225 else
226 return ip_finish_output2(skb);
227 }
228
229 int ip_mc_output(struct sk_buff *skb)
230 {
231 struct sock *sk = skb->sk;
232 struct rtable *rt = skb_rtable(skb);
233 struct net_device *dev = rt->dst.dev;
234
235 /*
236 * If the indicated interface is up and running, send the packet.
237 */
238 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
239
240 skb->dev = dev;
241 skb->protocol = htons(ETH_P_IP);
242
243 /*
244 * Multicasts are looped back for other local users
245 */
246
247 if (rt->rt_flags&RTCF_MULTICAST) {
248 if (sk_mc_loop(sk)
249 #ifdef CONFIG_IP_MROUTE
250 /* Small optimization: do not loopback not local frames,
251 which returned after forwarding; they will be dropped
252 by ip_mr_input in any case.
253 Note, that local frames are looped back to be delivered
254 to local recipients.
255
256 This check is duplicated in ip_mr_input at the moment.
257 */
258 &&
259 ((rt->rt_flags & RTCF_LOCAL) ||
260 !(IPCB(skb)->flags & IPSKB_FORWARDED))
261 #endif
262 ) {
263 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
264 if (newskb)
265 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
266 newskb, NULL, newskb->dev,
267 dev_loopback_xmit);
268 }
269
270 /* Multicasts with ttl 0 must not go beyond the host */
271
272 if (ip_hdr(skb)->ttl == 0) {
273 kfree_skb(skb);
274 return 0;
275 }
276 }
277
278 if (rt->rt_flags&RTCF_BROADCAST) {
279 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
280 if (newskb)
281 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb,
282 NULL, newskb->dev, dev_loopback_xmit);
283 }
284
285 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL,
286 skb->dev, ip_finish_output,
287 !(IPCB(skb)->flags & IPSKB_REROUTED));
288 }
289
290 int ip_output(struct sk_buff *skb)
291 {
292 struct net_device *dev = skb_dst(skb)->dev;
293
294 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
295
296 skb->dev = dev;
297 skb->protocol = htons(ETH_P_IP);
298
299 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev,
300 ip_finish_output,
301 !(IPCB(skb)->flags & IPSKB_REROUTED));
302 }
303
304 /*
305 * copy saddr and daddr, possibly using 64bit load/stores
306 * Equivalent to :
307 * iph->saddr = fl4->saddr;
308 * iph->daddr = fl4->daddr;
309 */
310 static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
311 {
312 BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
313 offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
314 memcpy(&iph->saddr, &fl4->saddr,
315 sizeof(fl4->saddr) + sizeof(fl4->daddr));
316 }
317
318 int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
319 {
320 struct sock *sk = skb->sk;
321 struct inet_sock *inet = inet_sk(sk);
322 struct ip_options_rcu *inet_opt;
323 struct flowi4 *fl4;
324 struct rtable *rt;
325 struct iphdr *iph;
326 int res;
327
328 /* Skip all of this if the packet is already routed,
329 * f.e. by something like SCTP.
330 */
331 rcu_read_lock();
332 inet_opt = rcu_dereference(inet->inet_opt);
333 fl4 = &fl->u.ip4;
334 rt = skb_rtable(skb);
335 if (rt != NULL)
336 goto packet_routed;
337
338 /* Make sure we can route this packet. */
339 rt = (struct rtable *)__sk_dst_check(sk, 0);
340 if (rt == NULL) {
341 __be32 daddr;
342
343 /* Use correct destination address if we have options. */
344 daddr = inet->inet_daddr;
345 if (inet_opt && inet_opt->opt.srr)
346 daddr = inet_opt->opt.faddr;
347
348 /* If this fails, retransmit mechanism of transport layer will
349 * keep trying until route appears or the connection times
350 * itself out.
351 */
352 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
353 daddr, inet->inet_saddr,
354 inet->inet_dport,
355 inet->inet_sport,
356 sk->sk_protocol,
357 RT_CONN_FLAGS(sk),
358 sk->sk_bound_dev_if);
359 if (IS_ERR(rt))
360 goto no_route;
361 sk_setup_caps(sk, &rt->dst);
362 }
363 skb_dst_set_noref(skb, &rt->dst);
364
365 packet_routed:
366 if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
367 goto no_route;
368
369 /* OK, we know where to send it, allocate and build IP header. */
370 skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
371 skb_reset_network_header(skb);
372 iph = ip_hdr(skb);
373 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
374 if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df)
375 iph->frag_off = htons(IP_DF);
376 else
377 iph->frag_off = 0;
378 iph->ttl = ip_select_ttl(inet, &rt->dst);
379 iph->protocol = sk->sk_protocol;
380 ip_copy_addrs(iph, fl4);
381
382 /* Transport layer set skb->h.foo itself. */
383
384 if (inet_opt && inet_opt->opt.optlen) {
385 iph->ihl += inet_opt->opt.optlen >> 2;
386 ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
387 }
388
389 ip_select_ident_more(skb, &rt->dst, sk,
390 (skb_shinfo(skb)->gso_segs ?: 1) - 1);
391
392 skb->priority = sk->sk_priority;
393 skb->mark = sk->sk_mark;
394
395 res = ip_local_out(skb);
396 rcu_read_unlock();
397 return res;
398
399 no_route:
400 rcu_read_unlock();
401 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
402 kfree_skb(skb);
403 return -EHOSTUNREACH;
404 }
405 EXPORT_SYMBOL(ip_queue_xmit);
406
407
408 static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
409 {
410 to->pkt_type = from->pkt_type;
411 to->priority = from->priority;
412 to->protocol = from->protocol;
413 skb_dst_drop(to);
414 skb_dst_copy(to, from);
415 to->dev = from->dev;
416 to->mark = from->mark;
417
418 /* Copy the flags to each fragment. */
419 IPCB(to)->flags = IPCB(from)->flags;
420
421 #ifdef CONFIG_NET_SCHED
422 to->tc_index = from->tc_index;
423 #endif
424 nf_copy(to, from);
425 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
426 to->nf_trace = from->nf_trace;
427 #endif
428 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
429 to->ipvs_property = from->ipvs_property;
430 #endif
431 skb_copy_secmark(to, from);
432 }
433
434 /*
435 * This IP datagram is too large to be sent in one piece. Break it up into
436 * smaller pieces (each of size equal to IP header plus
437 * a block of the data of the original IP data part) that will yet fit in a
438 * single device frame, and queue such a frame for sending.
439 */
440
441 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
442 {
443 struct iphdr *iph;
444 int ptr;
445 struct net_device *dev;
446 struct sk_buff *skb2;
447 unsigned int mtu, hlen, left, len, ll_rs;
448 int offset;
449 __be16 not_last_frag;
450 struct rtable *rt = skb_rtable(skb);
451 int err = 0;
452 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
453
454 dev = rt->dst.dev;
455
456 /*
457 * Point into the IP datagram header.
458 */
459
460 iph = ip_hdr(skb);
461
462 mtu = ip_dst_mtu_maybe_forward(&rt->dst, forwarding);
463 if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->local_df) ||
464 (IPCB(skb)->frag_max_size &&
465 IPCB(skb)->frag_max_size > mtu))) {
466 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
467 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
468 htonl(mtu));
469 kfree_skb(skb);
470 return -EMSGSIZE;
471 }
472
473 /*
474 * Setup starting values.
475 */
476
477 hlen = iph->ihl * 4;
478 mtu = mtu - hlen; /* Size of data space */
479 #ifdef CONFIG_BRIDGE_NETFILTER
480 if (skb->nf_bridge)
481 mtu -= nf_bridge_mtu_reduction(skb);
482 #endif
483 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
484
485 /* When frag_list is given, use it. First, check its validity:
486 * some transformers could create wrong frag_list or break existing
487 * one, it is not prohibited. In this case fall back to copying.
488 *
489 * LATER: this step can be merged to real generation of fragments,
490 * we can switch to copy when see the first bad fragment.
491 */
492 if (skb_has_frag_list(skb)) {
493 struct sk_buff *frag, *frag2;
494 int first_len = skb_pagelen(skb);
495
496 if (first_len - hlen > mtu ||
497 ((first_len - hlen) & 7) ||
498 ip_is_fragment(iph) ||
499 skb_cloned(skb))
500 goto slow_path;
501
502 skb_walk_frags(skb, frag) {
503 /* Correct geometry. */
504 if (frag->len > mtu ||
505 ((frag->len & 7) && frag->next) ||
506 skb_headroom(frag) < hlen)
507 goto slow_path_clean;
508
509 /* Partially cloned skb? */
510 if (skb_shared(frag))
511 goto slow_path_clean;
512
513 BUG_ON(frag->sk);
514 if (skb->sk) {
515 frag->sk = skb->sk;
516 frag->destructor = sock_wfree;
517 }
518 skb->truesize -= frag->truesize;
519 }
520
521 /* Everything is OK. Generate! */
522
523 err = 0;
524 offset = 0;
525 frag = skb_shinfo(skb)->frag_list;
526 skb_frag_list_init(skb);
527 skb->data_len = first_len - skb_headlen(skb);
528 skb->len = first_len;
529 iph->tot_len = htons(first_len);
530 iph->frag_off = htons(IP_MF);
531 ip_send_check(iph);
532
533 for (;;) {
534 /* Prepare header of the next frame,
535 * before previous one went down. */
536 if (frag) {
537 frag->ip_summed = CHECKSUM_NONE;
538 skb_reset_transport_header(frag);
539 __skb_push(frag, hlen);
540 skb_reset_network_header(frag);
541 memcpy(skb_network_header(frag), iph, hlen);
542 iph = ip_hdr(frag);
543 iph->tot_len = htons(frag->len);
544 ip_copy_metadata(frag, skb);
545 if (offset == 0)
546 ip_options_fragment(frag);
547 offset += skb->len - hlen;
548 iph->frag_off = htons(offset>>3);
549 if (frag->next != NULL)
550 iph->frag_off |= htons(IP_MF);
551 /* Ready, complete checksum */
552 ip_send_check(iph);
553 }
554
555 err = output(skb);
556
557 if (!err)
558 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
559 if (err || !frag)
560 break;
561
562 skb = frag;
563 frag = skb->next;
564 skb->next = NULL;
565 }
566
567 if (err == 0) {
568 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
569 return 0;
570 }
571
572 while (frag) {
573 skb = frag->next;
574 kfree_skb(frag);
575 frag = skb;
576 }
577 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
578 return err;
579
580 slow_path_clean:
581 skb_walk_frags(skb, frag2) {
582 if (frag2 == frag)
583 break;
584 frag2->sk = NULL;
585 frag2->destructor = NULL;
586 skb->truesize += frag2->truesize;
587 }
588 }
589
590 slow_path:
591 /* for offloaded checksums cleanup checksum before fragmentation */
592 if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb))
593 goto fail;
594 iph = ip_hdr(skb);
595
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->csum = 0;
778
779
780 __skb_queue_tail(queue, skb);
781 } else if (skb_is_gso(skb)) {
782 goto append;
783 }
784
785 skb->ip_summed = CHECKSUM_PARTIAL;
786 /* specify the length of each IP datagram fragment */
787 skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen;
788 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
789
790 append:
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, maxnonfragsize;
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 maxnonfragsize = (inet->pmtudisc >= IP_PMTUDISC_DO) ?
829 mtu : 0xFFFF;
830
831 if (cork->length + length > maxnonfragsize - fragheaderlen) {
832 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
833 mtu - (opt ? opt->optlen : 0));
834 return -EMSGSIZE;
835 }
836
837 /*
838 * transhdrlen > 0 means that this is the first fragment and we wish
839 * it won't be fragmented in the future.
840 */
841 if (transhdrlen &&
842 length + fragheaderlen <= mtu &&
843 rt->dst.dev->features & NETIF_F_V4_CSUM &&
844 !exthdrlen)
845 csummode = CHECKSUM_PARTIAL;
846
847 cork->length += length;
848 if (((length > mtu) || (skb && skb_is_gso(skb))) &&
849 (sk->sk_protocol == IPPROTO_UDP) &&
850 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) {
851 err = ip_ufo_append_data(sk, queue, getfrag, from, length,
852 hh_len, fragheaderlen, transhdrlen,
853 maxfraglen, flags);
854 if (err)
855 goto error;
856 return 0;
857 }
858
859 /* So, what's going on in the loop below?
860 *
861 * We use calculated fragment length to generate chained skb,
862 * each of segments is IP fragment ready for sending to network after
863 * adding appropriate IP header.
864 */
865
866 if (!skb)
867 goto alloc_new_skb;
868
869 while (length > 0) {
870 /* Check if the remaining data fits into current packet. */
871 copy = mtu - skb->len;
872 if (copy < length)
873 copy = maxfraglen - skb->len;
874 if (copy <= 0) {
875 char *data;
876 unsigned int datalen;
877 unsigned int fraglen;
878 unsigned int fraggap;
879 unsigned int alloclen;
880 struct sk_buff *skb_prev;
881 alloc_new_skb:
882 skb_prev = skb;
883 if (skb_prev)
884 fraggap = skb_prev->len - maxfraglen;
885 else
886 fraggap = 0;
887
888 /*
889 * If remaining data exceeds the mtu,
890 * we know we need more fragment(s).
891 */
892 datalen = length + fraggap;
893 if (datalen > mtu - fragheaderlen)
894 datalen = maxfraglen - fragheaderlen;
895 fraglen = datalen + fragheaderlen;
896
897 if ((flags & MSG_MORE) &&
898 !(rt->dst.dev->features&NETIF_F_SG))
899 alloclen = mtu;
900 else
901 alloclen = fraglen;
902
903 alloclen += exthdrlen;
904
905 /* The last fragment gets additional space at tail.
906 * Note, with MSG_MORE we overallocate on fragments,
907 * because we have no idea what fragment will be
908 * the last.
909 */
910 if (datalen == length + fraggap)
911 alloclen += rt->dst.trailer_len;
912
913 if (transhdrlen) {
914 skb = sock_alloc_send_skb(sk,
915 alloclen + hh_len + 15,
916 (flags & MSG_DONTWAIT), &err);
917 } else {
918 skb = NULL;
919 if (atomic_read(&sk->sk_wmem_alloc) <=
920 2 * sk->sk_sndbuf)
921 skb = sock_wmalloc(sk,
922 alloclen + hh_len + 15, 1,
923 sk->sk_allocation);
924 if (unlikely(skb == NULL))
925 err = -ENOBUFS;
926 else
927 /* only the initial fragment is
928 time stamped */
929 cork->tx_flags = 0;
930 }
931 if (skb == NULL)
932 goto error;
933
934 /*
935 * Fill in the control structures
936 */
937 skb->ip_summed = csummode;
938 skb->csum = 0;
939 skb_reserve(skb, hh_len);
940 skb_shinfo(skb)->tx_flags = cork->tx_flags;
941
942 /*
943 * Find where to start putting bytes.
944 */
945 data = skb_put(skb, fraglen + exthdrlen);
946 skb_set_network_header(skb, exthdrlen);
947 skb->transport_header = (skb->network_header +
948 fragheaderlen);
949 data += fragheaderlen + exthdrlen;
950
951 if (fraggap) {
952 skb->csum = skb_copy_and_csum_bits(
953 skb_prev, maxfraglen,
954 data + transhdrlen, fraggap, 0);
955 skb_prev->csum = csum_sub(skb_prev->csum,
956 skb->csum);
957 data += fraggap;
958 pskb_trim_unique(skb_prev, maxfraglen);
959 }
960
961 copy = datalen - transhdrlen - fraggap;
962 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
963 err = -EFAULT;
964 kfree_skb(skb);
965 goto error;
966 }
967
968 offset += copy;
969 length -= datalen - fraggap;
970 transhdrlen = 0;
971 exthdrlen = 0;
972 csummode = CHECKSUM_NONE;
973
974 /*
975 * Put the packet on the pending queue.
976 */
977 __skb_queue_tail(queue, skb);
978 continue;
979 }
980
981 if (copy > length)
982 copy = length;
983
984 if (!(rt->dst.dev->features&NETIF_F_SG)) {
985 unsigned int off;
986
987 off = skb->len;
988 if (getfrag(from, skb_put(skb, copy),
989 offset, copy, off, skb) < 0) {
990 __skb_trim(skb, off);
991 err = -EFAULT;
992 goto error;
993 }
994 } else {
995 int i = skb_shinfo(skb)->nr_frags;
996
997 err = -ENOMEM;
998 if (!sk_page_frag_refill(sk, pfrag))
999 goto error;
1000
1001 if (!skb_can_coalesce(skb, i, pfrag->page,
1002 pfrag->offset)) {
1003 err = -EMSGSIZE;
1004 if (i == MAX_SKB_FRAGS)
1005 goto error;
1006
1007 __skb_fill_page_desc(skb, i, pfrag->page,
1008 pfrag->offset, 0);
1009 skb_shinfo(skb)->nr_frags = ++i;
1010 get_page(pfrag->page);
1011 }
1012 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1013 if (getfrag(from,
1014 page_address(pfrag->page) + pfrag->offset,
1015 offset, copy, skb->len, skb) < 0)
1016 goto error_efault;
1017
1018 pfrag->offset += copy;
1019 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1020 skb->len += copy;
1021 skb->data_len += copy;
1022 skb->truesize += copy;
1023 atomic_add(copy, &sk->sk_wmem_alloc);
1024 }
1025 offset += copy;
1026 length -= copy;
1027 }
1028
1029 return 0;
1030
1031 error_efault:
1032 err = -EFAULT;
1033 error:
1034 cork->length -= length;
1035 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1036 return err;
1037 }
1038
1039 static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1040 struct ipcm_cookie *ipc, struct rtable **rtp)
1041 {
1042 struct ip_options_rcu *opt;
1043 struct rtable *rt;
1044
1045 /*
1046 * setup for corking.
1047 */
1048 opt = ipc->opt;
1049 if (opt) {
1050 if (cork->opt == NULL) {
1051 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1052 sk->sk_allocation);
1053 if (unlikely(cork->opt == NULL))
1054 return -ENOBUFS;
1055 }
1056 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1057 cork->flags |= IPCORK_OPT;
1058 cork->addr = ipc->addr;
1059 }
1060 rt = *rtp;
1061 if (unlikely(!rt))
1062 return -EFAULT;
1063 /*
1064 * We steal reference to this route, caller should not release it
1065 */
1066 *rtp = NULL;
1067 cork->fragsize = ip_sk_use_pmtu(sk) ?
1068 dst_mtu(&rt->dst) : rt->dst.dev->mtu;
1069 cork->dst = &rt->dst;
1070 cork->length = 0;
1071 cork->ttl = ipc->ttl;
1072 cork->tos = ipc->tos;
1073 cork->priority = ipc->priority;
1074 cork->tx_flags = ipc->tx_flags;
1075
1076 return 0;
1077 }
1078
1079 /*
1080 * ip_append_data() and ip_append_page() can make one large IP datagram
1081 * from many pieces of data. Each pieces will be holded on the socket
1082 * until ip_push_pending_frames() is called. Each piece can be a page
1083 * or non-page data.
1084 *
1085 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1086 * this interface potentially.
1087 *
1088 * LATER: length must be adjusted by pad at tail, when it is required.
1089 */
1090 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1091 int getfrag(void *from, char *to, int offset, int len,
1092 int odd, struct sk_buff *skb),
1093 void *from, int length, int transhdrlen,
1094 struct ipcm_cookie *ipc, struct rtable **rtp,
1095 unsigned int flags)
1096 {
1097 struct inet_sock *inet = inet_sk(sk);
1098 int err;
1099
1100 if (flags&MSG_PROBE)
1101 return 0;
1102
1103 if (skb_queue_empty(&sk->sk_write_queue)) {
1104 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1105 if (err)
1106 return err;
1107 } else {
1108 transhdrlen = 0;
1109 }
1110
1111 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
1112 sk_page_frag(sk), getfrag,
1113 from, length, transhdrlen, flags);
1114 }
1115
1116 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1117 int offset, size_t size, int flags)
1118 {
1119 struct inet_sock *inet = inet_sk(sk);
1120 struct sk_buff *skb;
1121 struct rtable *rt;
1122 struct ip_options *opt = NULL;
1123 struct inet_cork *cork;
1124 int hh_len;
1125 int mtu;
1126 int len;
1127 int err;
1128 unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize;
1129
1130 if (inet->hdrincl)
1131 return -EPERM;
1132
1133 if (flags&MSG_PROBE)
1134 return 0;
1135
1136 if (skb_queue_empty(&sk->sk_write_queue))
1137 return -EINVAL;
1138
1139 cork = &inet->cork.base;
1140 rt = (struct rtable *)cork->dst;
1141 if (cork->flags & IPCORK_OPT)
1142 opt = cork->opt;
1143
1144 if (!(rt->dst.dev->features&NETIF_F_SG))
1145 return -EOPNOTSUPP;
1146
1147 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1148 mtu = cork->fragsize;
1149
1150 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1151 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1152 maxnonfragsize = (inet->pmtudisc >= IP_PMTUDISC_DO) ?
1153 mtu : 0xFFFF;
1154
1155 if (cork->length + size > maxnonfragsize - fragheaderlen) {
1156 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
1157 mtu - (opt ? opt->optlen : 0));
1158 return -EMSGSIZE;
1159 }
1160
1161 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1162 return -EINVAL;
1163
1164 cork->length += size;
1165 if ((size + skb->len > mtu) &&
1166 (sk->sk_protocol == IPPROTO_UDP) &&
1167 (rt->dst.dev->features & NETIF_F_UFO)) {
1168 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1169 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1170 }
1171
1172
1173 while (size > 0) {
1174 int i;
1175
1176 if (skb_is_gso(skb))
1177 len = size;
1178 else {
1179
1180 /* Check if the remaining data fits into current packet. */
1181 len = mtu - skb->len;
1182 if (len < size)
1183 len = maxfraglen - skb->len;
1184 }
1185 if (len <= 0) {
1186 struct sk_buff *skb_prev;
1187 int alloclen;
1188
1189 skb_prev = skb;
1190 fraggap = skb_prev->len - maxfraglen;
1191
1192 alloclen = fragheaderlen + hh_len + fraggap + 15;
1193 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1194 if (unlikely(!skb)) {
1195 err = -ENOBUFS;
1196 goto error;
1197 }
1198
1199 /*
1200 * Fill in the control structures
1201 */
1202 skb->ip_summed = CHECKSUM_NONE;
1203 skb->csum = 0;
1204 skb_reserve(skb, hh_len);
1205
1206 /*
1207 * Find where to start putting bytes.
1208 */
1209 skb_put(skb, fragheaderlen + fraggap);
1210 skb_reset_network_header(skb);
1211 skb->transport_header = (skb->network_header +
1212 fragheaderlen);
1213 if (fraggap) {
1214 skb->csum = skb_copy_and_csum_bits(skb_prev,
1215 maxfraglen,
1216 skb_transport_header(skb),
1217 fraggap, 0);
1218 skb_prev->csum = csum_sub(skb_prev->csum,
1219 skb->csum);
1220 pskb_trim_unique(skb_prev, maxfraglen);
1221 }
1222
1223 /*
1224 * Put the packet on the pending queue.
1225 */
1226 __skb_queue_tail(&sk->sk_write_queue, skb);
1227 continue;
1228 }
1229
1230 i = skb_shinfo(skb)->nr_frags;
1231 if (len > size)
1232 len = size;
1233 if (skb_can_coalesce(skb, i, page, offset)) {
1234 skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
1235 } else if (i < MAX_SKB_FRAGS) {
1236 get_page(page);
1237 skb_fill_page_desc(skb, i, page, offset, len);
1238 } else {
1239 err = -EMSGSIZE;
1240 goto error;
1241 }
1242
1243 if (skb->ip_summed == CHECKSUM_NONE) {
1244 __wsum csum;
1245 csum = csum_page(page, offset, len);
1246 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1247 }
1248
1249 skb->len += len;
1250 skb->data_len += len;
1251 skb->truesize += len;
1252 atomic_add(len, &sk->sk_wmem_alloc);
1253 offset += len;
1254 size -= len;
1255 }
1256 return 0;
1257
1258 error:
1259 cork->length -= size;
1260 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1261 return err;
1262 }
1263
1264 static void ip_cork_release(struct inet_cork *cork)
1265 {
1266 cork->flags &= ~IPCORK_OPT;
1267 kfree(cork->opt);
1268 cork->opt = NULL;
1269 dst_release(cork->dst);
1270 cork->dst = NULL;
1271 }
1272
1273 /*
1274 * Combined all pending IP fragments on the socket as one IP datagram
1275 * and push them out.
1276 */
1277 struct sk_buff *__ip_make_skb(struct sock *sk,
1278 struct flowi4 *fl4,
1279 struct sk_buff_head *queue,
1280 struct inet_cork *cork)
1281 {
1282 struct sk_buff *skb, *tmp_skb;
1283 struct sk_buff **tail_skb;
1284 struct inet_sock *inet = inet_sk(sk);
1285 struct net *net = sock_net(sk);
1286 struct ip_options *opt = NULL;
1287 struct rtable *rt = (struct rtable *)cork->dst;
1288 struct iphdr *iph;
1289 __be16 df = 0;
1290 __u8 ttl;
1291
1292 if ((skb = __skb_dequeue(queue)) == NULL)
1293 goto out;
1294 tail_skb = &(skb_shinfo(skb)->frag_list);
1295
1296 /* move skb->data to ip header from ext header */
1297 if (skb->data < skb_network_header(skb))
1298 __skb_pull(skb, skb_network_offset(skb));
1299 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1300 __skb_pull(tmp_skb, skb_network_header_len(skb));
1301 *tail_skb = tmp_skb;
1302 tail_skb = &(tmp_skb->next);
1303 skb->len += tmp_skb->len;
1304 skb->data_len += tmp_skb->len;
1305 skb->truesize += tmp_skb->truesize;
1306 tmp_skb->destructor = NULL;
1307 tmp_skb->sk = NULL;
1308 }
1309
1310 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1311 * to fragment the frame generated here. No matter, what transforms
1312 * how transforms change size of the packet, it will come out.
1313 */
1314 if (inet->pmtudisc < IP_PMTUDISC_DO)
1315 skb->local_df = 1;
1316
1317 /* DF bit is set when we want to see DF on outgoing frames.
1318 * If local_df is set too, we still allow to fragment this frame
1319 * locally. */
1320 if (inet->pmtudisc == IP_PMTUDISC_DO ||
1321 inet->pmtudisc == IP_PMTUDISC_PROBE ||
1322 (skb->len <= dst_mtu(&rt->dst) &&
1323 ip_dont_fragment(sk, &rt->dst)))
1324 df = htons(IP_DF);
1325
1326 if (cork->flags & IPCORK_OPT)
1327 opt = cork->opt;
1328
1329 if (cork->ttl != 0)
1330 ttl = cork->ttl;
1331 else if (rt->rt_type == RTN_MULTICAST)
1332 ttl = inet->mc_ttl;
1333 else
1334 ttl = ip_select_ttl(inet, &rt->dst);
1335
1336 iph = ip_hdr(skb);
1337 iph->version = 4;
1338 iph->ihl = 5;
1339 iph->tos = (cork->tos != -1) ? cork->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(skb, &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 = (cork->tos != -1) ? cork->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,
1441 &current->task_frag, getfrag,
1442 from, length, transhdrlen, flags);
1443 if (err) {
1444 __ip_flush_pending_frames(sk, &queue, &cork);
1445 return ERR_PTR(err);
1446 }
1447
1448 return __ip_make_skb(sk, fl4, &queue, &cork);
1449 }
1450
1451 /*
1452 * Fetch data from kernel space and fill in checksum if needed.
1453 */
1454 static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1455 int len, int odd, struct sk_buff *skb)
1456 {
1457 __wsum csum;
1458
1459 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1460 skb->csum = csum_block_add(skb->csum, csum, odd);
1461 return 0;
1462 }
1463
1464 /*
1465 * Generic function to send a packet as reply to another packet.
1466 * Used to send some TCP resets/acks so far.
1467 *
1468 * Use a fake percpu inet socket to avoid false sharing and contention.
1469 */
1470 static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
1471 .sk = {
1472 .__sk_common = {
1473 .skc_refcnt = ATOMIC_INIT(1),
1474 },
1475 .sk_wmem_alloc = ATOMIC_INIT(1),
1476 .sk_allocation = GFP_ATOMIC,
1477 .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE),
1478 },
1479 .pmtudisc = IP_PMTUDISC_WANT,
1480 .uc_ttl = -1,
1481 };
1482
1483 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
1484 __be32 saddr, const struct ip_reply_arg *arg,
1485 unsigned int len)
1486 {
1487 struct ip_options_data replyopts;
1488 struct ipcm_cookie ipc;
1489 struct flowi4 fl4;
1490 struct rtable *rt = skb_rtable(skb);
1491 struct sk_buff *nskb;
1492 struct sock *sk;
1493 struct inet_sock *inet;
1494
1495 if (ip_options_echo(&replyopts.opt.opt, skb))
1496 return;
1497
1498 ipc.addr = daddr;
1499 ipc.opt = NULL;
1500 ipc.tx_flags = 0;
1501 ipc.ttl = 0;
1502 ipc.tos = -1;
1503
1504 if (replyopts.opt.opt.optlen) {
1505 ipc.opt = &replyopts.opt;
1506
1507 if (replyopts.opt.opt.srr)
1508 daddr = replyopts.opt.opt.faddr;
1509 }
1510
1511 flowi4_init_output(&fl4, arg->bound_dev_if, 0,
1512 RT_TOS(arg->tos),
1513 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1514 ip_reply_arg_flowi_flags(arg),
1515 daddr, saddr,
1516 tcp_hdr(skb)->source, tcp_hdr(skb)->dest);
1517 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1518 rt = ip_route_output_key(net, &fl4);
1519 if (IS_ERR(rt))
1520 return;
1521
1522 inet = &get_cpu_var(unicast_sock);
1523
1524 inet->tos = arg->tos;
1525 sk = &inet->sk;
1526 sk->sk_priority = skb->priority;
1527 sk->sk_protocol = ip_hdr(skb)->protocol;
1528 sk->sk_bound_dev_if = arg->bound_dev_if;
1529 sock_net_set(sk, net);
1530 __skb_queue_head_init(&sk->sk_write_queue);
1531 sk->sk_sndbuf = sysctl_wmem_default;
1532 ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
1533 &ipc, &rt, MSG_DONTWAIT);
1534 nskb = skb_peek(&sk->sk_write_queue);
1535 if (nskb) {
1536 if (arg->csumoffset >= 0)
1537 *((__sum16 *)skb_transport_header(nskb) +
1538 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1539 arg->csum));
1540 nskb->ip_summed = CHECKSUM_NONE;
1541 skb_orphan(nskb);
1542 skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb));
1543 ip_push_pending_frames(sk, &fl4);
1544 }
1545
1546 put_cpu_var(unicast_sock);
1547
1548 ip_rt_put(rt);
1549 }
1550
1551 void __init ip_init(void)
1552 {
1553 ip_rt_init();
1554 inet_initpeers();
1555
1556 #if defined(CONFIG_IP_MULTICAST)
1557 igmp_mc_init();
1558 #endif
1559 }
Linux with added FPC-III support