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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 | (IPCB(skb)->frag_max_size && |
472 | IPCB(skb)->frag_max_size > dst_mtu(&rt->dst)))) { |
473 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
474 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, |
475 | htonl(ip_skb_dst_mtu(skb))); |
476 | kfree_skb(skb); |
477 | return -EMSGSIZE; |
478 | } |
479 | |
480 | /* |
481 | * Setup starting values. |
482 | */ |
483 | |
484 | hlen = iph->ihl * 4; |
485 | mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */ |
486 | #ifdef CONFIG_BRIDGE_NETFILTER |
487 | if (skb->nf_bridge) |
488 | mtu -= nf_bridge_mtu_reduction(skb); |
489 | #endif |
490 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; |
491 | |
492 | /* When frag_list is given, use it. First, check its validity: |
493 | * some transformers could create wrong frag_list or break existing |
494 | * one, it is not prohibited. In this case fall back to copying. |
495 | * |
496 | * LATER: this step can be merged to real generation of fragments, |
497 | * we can switch to copy when see the first bad fragment. |
498 | */ |
499 | if (skb_has_frag_list(skb)) { |
500 | struct sk_buff *frag, *frag2; |
501 | int first_len = skb_pagelen(skb); |
502 | |
503 | if (first_len - hlen > mtu || |
504 | ((first_len - hlen) & 7) || |
505 | ip_is_fragment(iph) || |
506 | skb_cloned(skb)) |
507 | goto slow_path; |
508 | |
509 | skb_walk_frags(skb, frag) { |
510 | /* Correct geometry. */ |
511 | if (frag->len > mtu || |
512 | ((frag->len & 7) && frag->next) || |
513 | skb_headroom(frag) < hlen) |
514 | goto slow_path_clean; |
515 | |
516 | /* Partially cloned skb? */ |
517 | if (skb_shared(frag)) |
518 | goto slow_path_clean; |
519 | |
520 | BUG_ON(frag->sk); |
521 | if (skb->sk) { |
522 | frag->sk = skb->sk; |
523 | frag->destructor = sock_wfree; |
524 | } |
525 | skb->truesize -= frag->truesize; |
526 | } |
527 | |
528 | /* Everything is OK. Generate! */ |
529 | |
530 | err = 0; |
531 | offset = 0; |
532 | frag = skb_shinfo(skb)->frag_list; |
533 | skb_frag_list_init(skb); |
534 | skb->data_len = first_len - skb_headlen(skb); |
535 | skb->len = first_len; |
536 | iph->tot_len = htons(first_len); |
537 | iph->frag_off = htons(IP_MF); |
538 | ip_send_check(iph); |
539 | |
540 | for (;;) { |
541 | /* Prepare header of the next frame, |
542 | * before previous one went down. */ |
543 | if (frag) { |
544 | frag->ip_summed = CHECKSUM_NONE; |
545 | skb_reset_transport_header(frag); |
546 | __skb_push(frag, hlen); |
547 | skb_reset_network_header(frag); |
548 | memcpy(skb_network_header(frag), iph, hlen); |
549 | iph = ip_hdr(frag); |
550 | iph->tot_len = htons(frag->len); |
551 | ip_copy_metadata(frag, skb); |
552 | if (offset == 0) |
553 | ip_options_fragment(frag); |
554 | offset += skb->len - hlen; |
555 | iph->frag_off = htons(offset>>3); |
556 | if (frag->next != NULL) |
557 | iph->frag_off |= htons(IP_MF); |
558 | /* Ready, complete checksum */ |
559 | ip_send_check(iph); |
560 | } |
561 | |
562 | err = output(skb); |
563 | |
564 | if (!err) |
565 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); |
566 | if (err || !frag) |
567 | break; |
568 | |
569 | skb = frag; |
570 | frag = skb->next; |
571 | skb->next = NULL; |
572 | } |
573 | |
574 | if (err == 0) { |
575 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); |
576 | return 0; |
577 | } |
578 | |
579 | while (frag) { |
580 | skb = frag->next; |
581 | kfree_skb(frag); |
582 | frag = skb; |
583 | } |
584 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
585 | return err; |
586 | |
587 | slow_path_clean: |
588 | skb_walk_frags(skb, frag2) { |
589 | if (frag2 == frag) |
590 | break; |
591 | frag2->sk = NULL; |
592 | frag2->destructor = NULL; |
593 | skb->truesize += frag2->truesize; |
594 | } |
595 | } |
596 | |
597 | slow_path: |
598 | /* for offloaded checksums cleanup checksum before fragmentation */ |
599 | if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb)) |
600 | goto fail; |
601 | iph = ip_hdr(skb); |
602 | |
603 | left = skb->len - hlen; /* Space per frame */ |
604 | ptr = hlen; /* Where to start from */ |
605 | |
606 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, |
607 | * we need to make room for the encapsulating header |
608 | */ |
609 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb)); |
610 | |
611 | /* |
612 | * Fragment the datagram. |
613 | */ |
614 | |
615 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; |
616 | not_last_frag = iph->frag_off & htons(IP_MF); |
617 | |
618 | /* |
619 | * Keep copying data until we run out. |
620 | */ |
621 | |
622 | while (left > 0) { |
623 | len = left; |
624 | /* IF: it doesn't fit, use 'mtu' - the data space left */ |
625 | if (len > mtu) |
626 | len = mtu; |
627 | /* IF: we are not sending up to and including the packet end |
628 | then align the next start on an eight byte boundary */ |
629 | if (len < left) { |
630 | len &= ~7; |
631 | } |
632 | /* |
633 | * Allocate buffer. |
634 | */ |
635 | |
636 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { |
637 | NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); |
638 | err = -ENOMEM; |
639 | goto fail; |
640 | } |
641 | |
642 | /* |
643 | * Set up data on packet |
644 | */ |
645 | |
646 | ip_copy_metadata(skb2, skb); |
647 | skb_reserve(skb2, ll_rs); |
648 | skb_put(skb2, len + hlen); |
649 | skb_reset_network_header(skb2); |
650 | skb2->transport_header = skb2->network_header + hlen; |
651 | |
652 | /* |
653 | * Charge the memory for the fragment to any owner |
654 | * it might possess |
655 | */ |
656 | |
657 | if (skb->sk) |
658 | skb_set_owner_w(skb2, skb->sk); |
659 | |
660 | /* |
661 | * Copy the packet header into the new buffer. |
662 | */ |
663 | |
664 | skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); |
665 | |
666 | /* |
667 | * Copy a block of the IP datagram. |
668 | */ |
669 | if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) |
670 | BUG(); |
671 | left -= len; |
672 | |
673 | /* |
674 | * Fill in the new header fields. |
675 | */ |
676 | iph = ip_hdr(skb2); |
677 | iph->frag_off = htons((offset >> 3)); |
678 | |
679 | /* ANK: dirty, but effective trick. Upgrade options only if |
680 | * the segment to be fragmented was THE FIRST (otherwise, |
681 | * options are already fixed) and make it ONCE |
682 | * on the initial skb, so that all the following fragments |
683 | * will inherit fixed options. |
684 | */ |
685 | if (offset == 0) |
686 | ip_options_fragment(skb); |
687 | |
688 | /* |
689 | * Added AC : If we are fragmenting a fragment that's not the |
690 | * last fragment then keep MF on each bit |
691 | */ |
692 | if (left > 0 || not_last_frag) |
693 | iph->frag_off |= htons(IP_MF); |
694 | ptr += len; |
695 | offset += len; |
696 | |
697 | /* |
698 | * Put this fragment into the sending queue. |
699 | */ |
700 | iph->tot_len = htons(len + hlen); |
701 | |
702 | ip_send_check(iph); |
703 | |
704 | err = output(skb2); |
705 | if (err) |
706 | goto fail; |
707 | |
708 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); |
709 | } |
710 | consume_skb(skb); |
711 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); |
712 | return err; |
713 | |
714 | fail: |
715 | kfree_skb(skb); |
716 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
717 | return err; |
718 | } |
719 | EXPORT_SYMBOL(ip_fragment); |
720 | |
721 | int |
722 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) |
723 | { |
724 | struct iovec *iov = from; |
725 | |
726 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
727 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) |
728 | return -EFAULT; |
729 | } else { |
730 | __wsum csum = 0; |
731 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) |
732 | return -EFAULT; |
733 | skb->csum = csum_block_add(skb->csum, csum, odd); |
734 | } |
735 | return 0; |
736 | } |
737 | EXPORT_SYMBOL(ip_generic_getfrag); |
738 | |
739 | static inline __wsum |
740 | csum_page(struct page *page, int offset, int copy) |
741 | { |
742 | char *kaddr; |
743 | __wsum csum; |
744 | kaddr = kmap(page); |
745 | csum = csum_partial(kaddr + offset, copy, 0); |
746 | kunmap(page); |
747 | return csum; |
748 | } |
749 | |
750 | static inline int ip_ufo_append_data(struct sock *sk, |
751 | struct sk_buff_head *queue, |
752 | int getfrag(void *from, char *to, int offset, int len, |
753 | int odd, struct sk_buff *skb), |
754 | void *from, int length, int hh_len, int fragheaderlen, |
755 | int transhdrlen, int maxfraglen, unsigned int flags) |
756 | { |
757 | struct sk_buff *skb; |
758 | int err; |
759 | |
760 | /* There is support for UDP fragmentation offload by network |
761 | * device, so create one single skb packet containing complete |
762 | * udp datagram |
763 | */ |
764 | if ((skb = skb_peek_tail(queue)) == NULL) { |
765 | skb = sock_alloc_send_skb(sk, |
766 | hh_len + fragheaderlen + transhdrlen + 20, |
767 | (flags & MSG_DONTWAIT), &err); |
768 | |
769 | if (skb == NULL) |
770 | return err; |
771 | |
772 | /* reserve space for Hardware header */ |
773 | skb_reserve(skb, hh_len); |
774 | |
775 | /* create space for UDP/IP header */ |
776 | skb_put(skb, fragheaderlen + transhdrlen); |
777 | |
778 | /* initialize network header pointer */ |
779 | skb_reset_network_header(skb); |
780 | |
781 | /* initialize protocol header pointer */ |
782 | skb->transport_header = skb->network_header + fragheaderlen; |
783 | |
784 | skb->ip_summed = CHECKSUM_PARTIAL; |
785 | skb->csum = 0; |
786 | |
787 | /* specify the length of each IP datagram fragment */ |
788 | skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen; |
789 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; |
790 | __skb_queue_tail(queue, skb); |
791 | } |
792 | |
793 | return skb_append_datato_frags(sk, skb, getfrag, from, |
794 | (length - transhdrlen)); |
795 | } |
796 | |
797 | static int __ip_append_data(struct sock *sk, |
798 | struct flowi4 *fl4, |
799 | struct sk_buff_head *queue, |
800 | struct inet_cork *cork, |
801 | struct page_frag *pfrag, |
802 | int getfrag(void *from, char *to, int offset, |
803 | int len, int odd, struct sk_buff *skb), |
804 | void *from, int length, int transhdrlen, |
805 | unsigned int flags) |
806 | { |
807 | struct inet_sock *inet = inet_sk(sk); |
808 | struct sk_buff *skb; |
809 | |
810 | struct ip_options *opt = cork->opt; |
811 | int hh_len; |
812 | int exthdrlen; |
813 | int mtu; |
814 | int copy; |
815 | int err; |
816 | int offset = 0; |
817 | unsigned int maxfraglen, fragheaderlen; |
818 | int csummode = CHECKSUM_NONE; |
819 | struct rtable *rt = (struct rtable *)cork->dst; |
820 | |
821 | skb = skb_peek_tail(queue); |
822 | |
823 | exthdrlen = !skb ? rt->dst.header_len : 0; |
824 | mtu = cork->fragsize; |
825 | |
826 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
827 | |
828 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); |
829 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; |
830 | |
831 | if (cork->length + length > 0xFFFF - fragheaderlen) { |
832 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, |
833 | mtu-exthdrlen); |
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 inet_sock *inet = inet_sk(sk); |
1043 | struct ip_options_rcu *opt; |
1044 | struct rtable *rt; |
1045 | |
1046 | /* |
1047 | * setup for corking. |
1048 | */ |
1049 | opt = ipc->opt; |
1050 | if (opt) { |
1051 | if (cork->opt == NULL) { |
1052 | cork->opt = kmalloc(sizeof(struct ip_options) + 40, |
1053 | sk->sk_allocation); |
1054 | if (unlikely(cork->opt == NULL)) |
1055 | return -ENOBUFS; |
1056 | } |
1057 | memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen); |
1058 | cork->flags |= IPCORK_OPT; |
1059 | cork->addr = ipc->addr; |
1060 | } |
1061 | rt = *rtp; |
1062 | if (unlikely(!rt)) |
1063 | return -EFAULT; |
1064 | /* |
1065 | * We steal reference to this route, caller should not release it |
1066 | */ |
1067 | *rtp = NULL; |
1068 | cork->fragsize = inet->pmtudisc == IP_PMTUDISC_PROBE ? |
1069 | rt->dst.dev->mtu : dst_mtu(&rt->dst); |
1070 | cork->dst = &rt->dst; |
1071 | cork->length = 0; |
1072 | cork->tx_flags = ipc->tx_flags; |
1073 | |
1074 | return 0; |
1075 | } |
1076 | |
1077 | /* |
1078 | * ip_append_data() and ip_append_page() can make one large IP datagram |
1079 | * from many pieces of data. Each pieces will be holded on the socket |
1080 | * until ip_push_pending_frames() is called. Each piece can be a page |
1081 | * or non-page data. |
1082 | * |
1083 | * Not only UDP, other transport protocols - e.g. raw sockets - can use |
1084 | * this interface potentially. |
1085 | * |
1086 | * LATER: length must be adjusted by pad at tail, when it is required. |
1087 | */ |
1088 | int ip_append_data(struct sock *sk, struct flowi4 *fl4, |
1089 | int getfrag(void *from, char *to, int offset, int len, |
1090 | int odd, struct sk_buff *skb), |
1091 | void *from, int length, int transhdrlen, |
1092 | struct ipcm_cookie *ipc, struct rtable **rtp, |
1093 | unsigned int flags) |
1094 | { |
1095 | struct inet_sock *inet = inet_sk(sk); |
1096 | int err; |
1097 | |
1098 | if (flags&MSG_PROBE) |
1099 | return 0; |
1100 | |
1101 | if (skb_queue_empty(&sk->sk_write_queue)) { |
1102 | err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp); |
1103 | if (err) |
1104 | return err; |
1105 | } else { |
1106 | transhdrlen = 0; |
1107 | } |
1108 | |
1109 | return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base, |
1110 | sk_page_frag(sk), getfrag, |
1111 | from, length, transhdrlen, flags); |
1112 | } |
1113 | |
1114 | ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, |
1115 | int offset, size_t size, int flags) |
1116 | { |
1117 | struct inet_sock *inet = inet_sk(sk); |
1118 | struct sk_buff *skb; |
1119 | struct rtable *rt; |
1120 | struct ip_options *opt = NULL; |
1121 | struct inet_cork *cork; |
1122 | int hh_len; |
1123 | int mtu; |
1124 | int len; |
1125 | int err; |
1126 | unsigned int maxfraglen, fragheaderlen, fraggap; |
1127 | |
1128 | if (inet->hdrincl) |
1129 | return -EPERM; |
1130 | |
1131 | if (flags&MSG_PROBE) |
1132 | return 0; |
1133 | |
1134 | if (skb_queue_empty(&sk->sk_write_queue)) |
1135 | return -EINVAL; |
1136 | |
1137 | cork = &inet->cork.base; |
1138 | rt = (struct rtable *)cork->dst; |
1139 | if (cork->flags & IPCORK_OPT) |
1140 | opt = cork->opt; |
1141 | |
1142 | if (!(rt->dst.dev->features&NETIF_F_SG)) |
1143 | return -EOPNOTSUPP; |
1144 | |
1145 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
1146 | mtu = cork->fragsize; |
1147 | |
1148 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); |
1149 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; |
1150 | |
1151 | if (cork->length + size > 0xFFFF - fragheaderlen) { |
1152 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, mtu); |
1153 | return -EMSGSIZE; |
1154 | } |
1155 | |
1156 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) |
1157 | return -EINVAL; |
1158 | |
1159 | cork->length += size; |
1160 | if ((size + skb->len > mtu) && |
1161 | (sk->sk_protocol == IPPROTO_UDP) && |
1162 | (rt->dst.dev->features & NETIF_F_UFO)) { |
1163 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; |
1164 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; |
1165 | } |
1166 | |
1167 | |
1168 | while (size > 0) { |
1169 | int i; |
1170 | |
1171 | if (skb_is_gso(skb)) |
1172 | len = size; |
1173 | else { |
1174 | |
1175 | /* Check if the remaining data fits into current packet. */ |
1176 | len = mtu - skb->len; |
1177 | if (len < size) |
1178 | len = maxfraglen - skb->len; |
1179 | } |
1180 | if (len <= 0) { |
1181 | struct sk_buff *skb_prev; |
1182 | int alloclen; |
1183 | |
1184 | skb_prev = skb; |
1185 | fraggap = skb_prev->len - maxfraglen; |
1186 | |
1187 | alloclen = fragheaderlen + hh_len + fraggap + 15; |
1188 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); |
1189 | if (unlikely(!skb)) { |
1190 | err = -ENOBUFS; |
1191 | goto error; |
1192 | } |
1193 | |
1194 | /* |
1195 | * Fill in the control structures |
1196 | */ |
1197 | skb->ip_summed = CHECKSUM_NONE; |
1198 | skb->csum = 0; |
1199 | skb_reserve(skb, hh_len); |
1200 | |
1201 | /* |
1202 | * Find where to start putting bytes. |
1203 | */ |
1204 | skb_put(skb, fragheaderlen + fraggap); |
1205 | skb_reset_network_header(skb); |
1206 | skb->transport_header = (skb->network_header + |
1207 | fragheaderlen); |
1208 | if (fraggap) { |
1209 | skb->csum = skb_copy_and_csum_bits(skb_prev, |
1210 | maxfraglen, |
1211 | skb_transport_header(skb), |
1212 | fraggap, 0); |
1213 | skb_prev->csum = csum_sub(skb_prev->csum, |
1214 | skb->csum); |
1215 | pskb_trim_unique(skb_prev, maxfraglen); |
1216 | } |
1217 | |
1218 | /* |
1219 | * Put the packet on the pending queue. |
1220 | */ |
1221 | __skb_queue_tail(&sk->sk_write_queue, skb); |
1222 | continue; |
1223 | } |
1224 | |
1225 | i = skb_shinfo(skb)->nr_frags; |
1226 | if (len > size) |
1227 | len = size; |
1228 | if (skb_can_coalesce(skb, i, page, offset)) { |
1229 | skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len); |
1230 | } else if (i < MAX_SKB_FRAGS) { |
1231 | get_page(page); |
1232 | skb_fill_page_desc(skb, i, page, offset, len); |
1233 | } else { |
1234 | err = -EMSGSIZE; |
1235 | goto error; |
1236 | } |
1237 | |
1238 | if (skb->ip_summed == CHECKSUM_NONE) { |
1239 | __wsum csum; |
1240 | csum = csum_page(page, offset, len); |
1241 | skb->csum = csum_block_add(skb->csum, csum, skb->len); |
1242 | } |
1243 | |
1244 | skb->len += len; |
1245 | skb->data_len += len; |
1246 | skb->truesize += len; |
1247 | atomic_add(len, &sk->sk_wmem_alloc); |
1248 | offset += len; |
1249 | size -= len; |
1250 | } |
1251 | return 0; |
1252 | |
1253 | error: |
1254 | cork->length -= size; |
1255 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
1256 | return err; |
1257 | } |
1258 | |
1259 | static void ip_cork_release(struct inet_cork *cork) |
1260 | { |
1261 | cork->flags &= ~IPCORK_OPT; |
1262 | kfree(cork->opt); |
1263 | cork->opt = NULL; |
1264 | dst_release(cork->dst); |
1265 | cork->dst = NULL; |
1266 | } |
1267 | |
1268 | /* |
1269 | * Combined all pending IP fragments on the socket as one IP datagram |
1270 | * and push them out. |
1271 | */ |
1272 | struct sk_buff *__ip_make_skb(struct sock *sk, |
1273 | struct flowi4 *fl4, |
1274 | struct sk_buff_head *queue, |
1275 | struct inet_cork *cork) |
1276 | { |
1277 | struct sk_buff *skb, *tmp_skb; |
1278 | struct sk_buff **tail_skb; |
1279 | struct inet_sock *inet = inet_sk(sk); |
1280 | struct net *net = sock_net(sk); |
1281 | struct ip_options *opt = NULL; |
1282 | struct rtable *rt = (struct rtable *)cork->dst; |
1283 | struct iphdr *iph; |
1284 | __be16 df = 0; |
1285 | __u8 ttl; |
1286 | |
1287 | if ((skb = __skb_dequeue(queue)) == NULL) |
1288 | goto out; |
1289 | tail_skb = &(skb_shinfo(skb)->frag_list); |
1290 | |
1291 | /* move skb->data to ip header from ext header */ |
1292 | if (skb->data < skb_network_header(skb)) |
1293 | __skb_pull(skb, skb_network_offset(skb)); |
1294 | while ((tmp_skb = __skb_dequeue(queue)) != NULL) { |
1295 | __skb_pull(tmp_skb, skb_network_header_len(skb)); |
1296 | *tail_skb = tmp_skb; |
1297 | tail_skb = &(tmp_skb->next); |
1298 | skb->len += tmp_skb->len; |
1299 | skb->data_len += tmp_skb->len; |
1300 | skb->truesize += tmp_skb->truesize; |
1301 | tmp_skb->destructor = NULL; |
1302 | tmp_skb->sk = NULL; |
1303 | } |
1304 | |
1305 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow |
1306 | * to fragment the frame generated here. No matter, what transforms |
1307 | * how transforms change size of the packet, it will come out. |
1308 | */ |
1309 | if (inet->pmtudisc < IP_PMTUDISC_DO) |
1310 | skb->local_df = 1; |
1311 | |
1312 | /* DF bit is set when we want to see DF on outgoing frames. |
1313 | * If local_df is set too, we still allow to fragment this frame |
1314 | * locally. */ |
1315 | if (inet->pmtudisc >= IP_PMTUDISC_DO || |
1316 | (skb->len <= dst_mtu(&rt->dst) && |
1317 | ip_dont_fragment(sk, &rt->dst))) |
1318 | df = htons(IP_DF); |
1319 | |
1320 | if (cork->flags & IPCORK_OPT) |
1321 | opt = cork->opt; |
1322 | |
1323 | if (rt->rt_type == RTN_MULTICAST) |
1324 | ttl = inet->mc_ttl; |
1325 | else |
1326 | ttl = ip_select_ttl(inet, &rt->dst); |
1327 | |
1328 | iph = (struct iphdr *)skb->data; |
1329 | iph->version = 4; |
1330 | iph->ihl = 5; |
1331 | iph->tos = inet->tos; |
1332 | iph->frag_off = df; |
1333 | iph->ttl = ttl; |
1334 | iph->protocol = sk->sk_protocol; |
1335 | ip_copy_addrs(iph, fl4); |
1336 | ip_select_ident(iph, &rt->dst, sk); |
1337 | |
1338 | if (opt) { |
1339 | iph->ihl += opt->optlen>>2; |
1340 | ip_options_build(skb, opt, cork->addr, rt, 0); |
1341 | } |
1342 | |
1343 | skb->priority = sk->sk_priority; |
1344 | skb->mark = sk->sk_mark; |
1345 | /* |
1346 | * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec |
1347 | * on dst refcount |
1348 | */ |
1349 | cork->dst = NULL; |
1350 | skb_dst_set(skb, &rt->dst); |
1351 | |
1352 | if (iph->protocol == IPPROTO_ICMP) |
1353 | icmp_out_count(net, ((struct icmphdr *) |
1354 | skb_transport_header(skb))->type); |
1355 | |
1356 | ip_cork_release(cork); |
1357 | out: |
1358 | return skb; |
1359 | } |
1360 | |
1361 | int ip_send_skb(struct net *net, struct sk_buff *skb) |
1362 | { |
1363 | int err; |
1364 | |
1365 | err = ip_local_out(skb); |
1366 | if (err) { |
1367 | if (err > 0) |
1368 | err = net_xmit_errno(err); |
1369 | if (err) |
1370 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); |
1371 | } |
1372 | |
1373 | return err; |
1374 | } |
1375 | |
1376 | int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4) |
1377 | { |
1378 | struct sk_buff *skb; |
1379 | |
1380 | skb = ip_finish_skb(sk, fl4); |
1381 | if (!skb) |
1382 | return 0; |
1383 | |
1384 | /* Netfilter gets whole the not fragmented skb. */ |
1385 | return ip_send_skb(sock_net(sk), skb); |
1386 | } |
1387 | |
1388 | /* |
1389 | * Throw away all pending data on the socket. |
1390 | */ |
1391 | static void __ip_flush_pending_frames(struct sock *sk, |
1392 | struct sk_buff_head *queue, |
1393 | struct inet_cork *cork) |
1394 | { |
1395 | struct sk_buff *skb; |
1396 | |
1397 | while ((skb = __skb_dequeue_tail(queue)) != NULL) |
1398 | kfree_skb(skb); |
1399 | |
1400 | ip_cork_release(cork); |
1401 | } |
1402 | |
1403 | void ip_flush_pending_frames(struct sock *sk) |
1404 | { |
1405 | __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base); |
1406 | } |
1407 | |
1408 | struct sk_buff *ip_make_skb(struct sock *sk, |
1409 | struct flowi4 *fl4, |
1410 | int getfrag(void *from, char *to, int offset, |
1411 | int len, int odd, struct sk_buff *skb), |
1412 | void *from, int length, int transhdrlen, |
1413 | struct ipcm_cookie *ipc, struct rtable **rtp, |
1414 | unsigned int flags) |
1415 | { |
1416 | struct inet_cork cork; |
1417 | struct sk_buff_head queue; |
1418 | int err; |
1419 | |
1420 | if (flags & MSG_PROBE) |
1421 | return NULL; |
1422 | |
1423 | __skb_queue_head_init(&queue); |
1424 | |
1425 | cork.flags = 0; |
1426 | cork.addr = 0; |
1427 | cork.opt = NULL; |
1428 | err = ip_setup_cork(sk, &cork, ipc, rtp); |
1429 | if (err) |
1430 | return ERR_PTR(err); |
1431 | |
1432 | err = __ip_append_data(sk, fl4, &queue, &cork, |
1433 | ¤t->task_frag, getfrag, |
1434 | from, length, transhdrlen, flags); |
1435 | if (err) { |
1436 | __ip_flush_pending_frames(sk, &queue, &cork); |
1437 | return ERR_PTR(err); |
1438 | } |
1439 | |
1440 | return __ip_make_skb(sk, fl4, &queue, &cork); |
1441 | } |
1442 | |
1443 | /* |
1444 | * Fetch data from kernel space and fill in checksum if needed. |
1445 | */ |
1446 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, |
1447 | int len, int odd, struct sk_buff *skb) |
1448 | { |
1449 | __wsum csum; |
1450 | |
1451 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); |
1452 | skb->csum = csum_block_add(skb->csum, csum, odd); |
1453 | return 0; |
1454 | } |
1455 | |
1456 | /* |
1457 | * Generic function to send a packet as reply to another packet. |
1458 | * Used to send some TCP resets/acks so far. |
1459 | * |
1460 | * Use a fake percpu inet socket to avoid false sharing and contention. |
1461 | */ |
1462 | static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = { |
1463 | .sk = { |
1464 | .__sk_common = { |
1465 | .skc_refcnt = ATOMIC_INIT(1), |
1466 | }, |
1467 | .sk_wmem_alloc = ATOMIC_INIT(1), |
1468 | .sk_allocation = GFP_ATOMIC, |
1469 | .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE), |
1470 | }, |
1471 | .pmtudisc = IP_PMTUDISC_WANT, |
1472 | .uc_ttl = -1, |
1473 | }; |
1474 | |
1475 | void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, |
1476 | __be32 saddr, const struct ip_reply_arg *arg, |
1477 | unsigned int len) |
1478 | { |
1479 | struct ip_options_data replyopts; |
1480 | struct ipcm_cookie ipc; |
1481 | struct flowi4 fl4; |
1482 | struct rtable *rt = skb_rtable(skb); |
1483 | struct sk_buff *nskb; |
1484 | struct sock *sk; |
1485 | struct inet_sock *inet; |
1486 | |
1487 | if (ip_options_echo(&replyopts.opt.opt, skb)) |
1488 | return; |
1489 | |
1490 | ipc.addr = daddr; |
1491 | ipc.opt = NULL; |
1492 | ipc.tx_flags = 0; |
1493 | |
1494 | if (replyopts.opt.opt.optlen) { |
1495 | ipc.opt = &replyopts.opt; |
1496 | |
1497 | if (replyopts.opt.opt.srr) |
1498 | daddr = replyopts.opt.opt.faddr; |
1499 | } |
1500 | |
1501 | flowi4_init_output(&fl4, arg->bound_dev_if, 0, |
1502 | RT_TOS(arg->tos), |
1503 | RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol, |
1504 | ip_reply_arg_flowi_flags(arg), |
1505 | daddr, saddr, |
1506 | tcp_hdr(skb)->source, tcp_hdr(skb)->dest); |
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 | } |
1550 |
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javiroman/ks7010
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9