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Commit | Line | Data |
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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 <asm/system.h> | |
47 | #include <linux/module.h> | |
48 | #include <linux/types.h> | |
49 | #include <linux/kernel.h> | |
50 | #include <linux/mm.h> | |
51 | #include <linux/string.h> | |
52 | #include <linux/errno.h> | |
53 | #include <linux/highmem.h> | |
54 | ||
55 | #include <linux/socket.h> | |
56 | #include <linux/sockios.h> | |
57 | #include <linux/in.h> | |
58 | #include <linux/inet.h> | |
59 | #include <linux/netdevice.h> | |
60 | #include <linux/etherdevice.h> | |
61 | #include <linux/proc_fs.h> | |
62 | #include <linux/stat.h> | |
63 | #include <linux/init.h> | |
64 | ||
65 | #include <net/snmp.h> | |
66 | #include <net/ip.h> | |
67 | #include <net/protocol.h> | |
68 | #include <net/route.h> | |
69 | #include <net/xfrm.h> | |
70 | #include <linux/skbuff.h> | |
71 | #include <net/sock.h> | |
72 | #include <net/arp.h> | |
73 | #include <net/icmp.h> | |
74 | #include <net/checksum.h> | |
75 | #include <net/inetpeer.h> | |
76 | #include <linux/igmp.h> | |
77 | #include <linux/netfilter_ipv4.h> | |
78 | #include <linux/netfilter_bridge.h> | |
79 | #include <linux/mroute.h> | |
80 | #include <linux/netlink.h> | |
81 | #include <linux/tcp.h> | |
82 | ||
83 | int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; | |
84 | ||
85 | /* Generate a checksum for an outgoing IP datagram. */ | |
86 | __inline__ void ip_send_check(struct iphdr *iph) | |
87 | { | |
88 | iph->check = 0; | |
89 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
90 | } | |
91 | ||
92 | int __ip_local_out(struct sk_buff *skb) | |
93 | { | |
94 | struct iphdr *iph = ip_hdr(skb); | |
95 | ||
96 | iph->tot_len = htons(skb->len); | |
97 | ip_send_check(iph); | |
98 | return nf_hook(PF_INET, NF_INET_LOCAL_OUT, skb, NULL, skb->dst->dev, | |
99 | dst_output); | |
100 | } | |
101 | ||
102 | int ip_local_out(struct sk_buff *skb) | |
103 | { | |
104 | int err; | |
105 | ||
106 | err = __ip_local_out(skb); | |
107 | if (likely(err == 1)) | |
108 | err = dst_output(skb); | |
109 | ||
110 | return err; | |
111 | } | |
112 | EXPORT_SYMBOL_GPL(ip_local_out); | |
113 | ||
114 | /* dev_loopback_xmit for use with netfilter. */ | |
115 | static int ip_dev_loopback_xmit(struct sk_buff *newskb) | |
116 | { | |
117 | skb_reset_mac_header(newskb); | |
118 | __skb_pull(newskb, skb_network_offset(newskb)); | |
119 | newskb->pkt_type = PACKET_LOOPBACK; | |
120 | newskb->ip_summed = CHECKSUM_UNNECESSARY; | |
121 | WARN_ON(!newskb->dst); | |
122 | netif_rx(newskb); | |
123 | return 0; | |
124 | } | |
125 | ||
126 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) | |
127 | { | |
128 | int ttl = inet->uc_ttl; | |
129 | ||
130 | if (ttl < 0) | |
131 | ttl = dst_metric(dst, RTAX_HOPLIMIT); | |
132 | return ttl; | |
133 | } | |
134 | ||
135 | /* | |
136 | * Add an ip header to a skbuff and send it out. | |
137 | * | |
138 | */ | |
139 | int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, | |
140 | __be32 saddr, __be32 daddr, struct ip_options *opt) | |
141 | { | |
142 | struct inet_sock *inet = inet_sk(sk); | |
143 | struct rtable *rt = skb->rtable; | |
144 | struct iphdr *iph; | |
145 | ||
146 | /* Build the IP header. */ | |
147 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
148 | skb_reset_network_header(skb); | |
149 | iph = ip_hdr(skb); | |
150 | iph->version = 4; | |
151 | iph->ihl = 5; | |
152 | iph->tos = inet->tos; | |
153 | if (ip_dont_fragment(sk, &rt->u.dst)) | |
154 | iph->frag_off = htons(IP_DF); | |
155 | else | |
156 | iph->frag_off = 0; | |
157 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
158 | iph->daddr = rt->rt_dst; | |
159 | iph->saddr = rt->rt_src; | |
160 | iph->protocol = sk->sk_protocol; | |
161 | ip_select_ident(iph, &rt->u.dst, sk); | |
162 | ||
163 | if (opt && opt->optlen) { | |
164 | iph->ihl += opt->optlen>>2; | |
165 | ip_options_build(skb, opt, daddr, rt, 0); | |
166 | } | |
167 | ||
168 | skb->priority = sk->sk_priority; | |
169 | skb->mark = sk->sk_mark; | |
170 | ||
171 | /* Send it out. */ | |
172 | return ip_local_out(skb); | |
173 | } | |
174 | ||
175 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); | |
176 | ||
177 | static inline int ip_finish_output2(struct sk_buff *skb) | |
178 | { | |
179 | struct dst_entry *dst = skb->dst; | |
180 | struct rtable *rt = (struct rtable *)dst; | |
181 | struct net_device *dev = dst->dev; | |
182 | unsigned int hh_len = LL_RESERVED_SPACE(dev); | |
183 | ||
184 | if (rt->rt_type == RTN_MULTICAST) | |
185 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTMCASTPKTS); | |
186 | else if (rt->rt_type == RTN_BROADCAST) | |
187 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTBCASTPKTS); | |
188 | ||
189 | /* Be paranoid, rather than too clever. */ | |
190 | if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { | |
191 | struct sk_buff *skb2; | |
192 | ||
193 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
194 | if (skb2 == NULL) { | |
195 | kfree_skb(skb); | |
196 | return -ENOMEM; | |
197 | } | |
198 | if (skb->sk) | |
199 | skb_set_owner_w(skb2, skb->sk); | |
200 | kfree_skb(skb); | |
201 | skb = skb2; | |
202 | } | |
203 | ||
204 | if (dst->hh) | |
205 | return neigh_hh_output(dst->hh, skb); | |
206 | else if (dst->neighbour) | |
207 | return dst->neighbour->output(skb); | |
208 | ||
209 | if (net_ratelimit()) | |
210 | printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); | |
211 | kfree_skb(skb); | |
212 | return -EINVAL; | |
213 | } | |
214 | ||
215 | static inline int ip_skb_dst_mtu(struct sk_buff *skb) | |
216 | { | |
217 | struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL; | |
218 | ||
219 | return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ? | |
220 | skb->dst->dev->mtu : dst_mtu(skb->dst); | |
221 | } | |
222 | ||
223 | static int ip_finish_output(struct sk_buff *skb) | |
224 | { | |
225 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) | |
226 | /* Policy lookup after SNAT yielded a new policy */ | |
227 | if (skb->dst->xfrm != NULL) { | |
228 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
229 | return dst_output(skb); | |
230 | } | |
231 | #endif | |
232 | if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb)) | |
233 | return ip_fragment(skb, ip_finish_output2); | |
234 | else | |
235 | return ip_finish_output2(skb); | |
236 | } | |
237 | ||
238 | int ip_mc_output(struct sk_buff *skb) | |
239 | { | |
240 | struct sock *sk = skb->sk; | |
241 | struct rtable *rt = skb->rtable; | |
242 | struct net_device *dev = rt->u.dst.dev; | |
243 | ||
244 | /* | |
245 | * If the indicated interface is up and running, send the packet. | |
246 | */ | |
247 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTREQUESTS); | |
248 | ||
249 | skb->dev = dev; | |
250 | skb->protocol = htons(ETH_P_IP); | |
251 | ||
252 | /* | |
253 | * Multicasts are looped back for other local users | |
254 | */ | |
255 | ||
256 | if (rt->rt_flags&RTCF_MULTICAST) { | |
257 | if ((!sk || inet_sk(sk)->mc_loop) | |
258 | #ifdef CONFIG_IP_MROUTE | |
259 | /* Small optimization: do not loopback not local frames, | |
260 | which returned after forwarding; they will be dropped | |
261 | by ip_mr_input in any case. | |
262 | Note, that local frames are looped back to be delivered | |
263 | to local recipients. | |
264 | ||
265 | This check is duplicated in ip_mr_input at the moment. | |
266 | */ | |
267 | && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) | |
268 | #endif | |
269 | ) { | |
270 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
271 | if (newskb) | |
272 | NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb, | |
273 | NULL, newskb->dev, | |
274 | ip_dev_loopback_xmit); | |
275 | } | |
276 | ||
277 | /* Multicasts with ttl 0 must not go beyond the host */ | |
278 | ||
279 | if (ip_hdr(skb)->ttl == 0) { | |
280 | kfree_skb(skb); | |
281 | return 0; | |
282 | } | |
283 | } | |
284 | ||
285 | if (rt->rt_flags&RTCF_BROADCAST) { | |
286 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
287 | if (newskb) | |
288 | NF_HOOK(PF_INET, NF_INET_POST_ROUTING, newskb, NULL, | |
289 | newskb->dev, ip_dev_loopback_xmit); | |
290 | } | |
291 | ||
292 | return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, skb->dev, | |
293 | ip_finish_output, | |
294 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
295 | } | |
296 | ||
297 | int ip_output(struct sk_buff *skb) | |
298 | { | |
299 | struct net_device *dev = skb->dst->dev; | |
300 | ||
301 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_OUTREQUESTS); | |
302 | ||
303 | skb->dev = dev; | |
304 | skb->protocol = htons(ETH_P_IP); | |
305 | ||
306 | return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb, NULL, dev, | |
307 | ip_finish_output, | |
308 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
309 | } | |
310 | ||
311 | int ip_queue_xmit(struct sk_buff *skb, int ipfragok) | |
312 | { | |
313 | struct sock *sk = skb->sk; | |
314 | struct inet_sock *inet = inet_sk(sk); | |
315 | struct ip_options *opt = inet->opt; | |
316 | struct rtable *rt; | |
317 | struct iphdr *iph; | |
318 | ||
319 | /* Skip all of this if the packet is already routed, | |
320 | * f.e. by something like SCTP. | |
321 | */ | |
322 | rt = skb->rtable; | |
323 | if (rt != NULL) | |
324 | goto packet_routed; | |
325 | ||
326 | /* Make sure we can route this packet. */ | |
327 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
328 | if (rt == NULL) { | |
329 | __be32 daddr; | |
330 | ||
331 | /* Use correct destination address if we have options. */ | |
332 | daddr = inet->daddr; | |
333 | if(opt && opt->srr) | |
334 | daddr = opt->faddr; | |
335 | ||
336 | { | |
337 | struct flowi fl = { .oif = sk->sk_bound_dev_if, | |
338 | .nl_u = { .ip4_u = | |
339 | { .daddr = daddr, | |
340 | .saddr = inet->saddr, | |
341 | .tos = RT_CONN_FLAGS(sk) } }, | |
342 | .proto = sk->sk_protocol, | |
343 | .flags = inet_sk_flowi_flags(sk), | |
344 | .uli_u = { .ports = | |
345 | { .sport = inet->sport, | |
346 | .dport = inet->dport } } }; | |
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 | security_sk_classify_flow(sk, &fl); | |
353 | if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0)) | |
354 | goto no_route; | |
355 | } | |
356 | sk_setup_caps(sk, &rt->u.dst); | |
357 | } | |
358 | skb->dst = dst_clone(&rt->u.dst); | |
359 | ||
360 | packet_routed: | |
361 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) | |
362 | goto no_route; | |
363 | ||
364 | /* OK, we know where to send it, allocate and build IP header. */ | |
365 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
366 | skb_reset_network_header(skb); | |
367 | iph = ip_hdr(skb); | |
368 | *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); | |
369 | if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) | |
370 | iph->frag_off = htons(IP_DF); | |
371 | else | |
372 | iph->frag_off = 0; | |
373 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
374 | iph->protocol = sk->sk_protocol; | |
375 | iph->saddr = rt->rt_src; | |
376 | iph->daddr = rt->rt_dst; | |
377 | /* Transport layer set skb->h.foo itself. */ | |
378 | ||
379 | if (opt && opt->optlen) { | |
380 | iph->ihl += opt->optlen >> 2; | |
381 | ip_options_build(skb, opt, inet->daddr, rt, 0); | |
382 | } | |
383 | ||
384 | ip_select_ident_more(iph, &rt->u.dst, sk, | |
385 | (skb_shinfo(skb)->gso_segs ?: 1) - 1); | |
386 | ||
387 | skb->priority = sk->sk_priority; | |
388 | skb->mark = sk->sk_mark; | |
389 | ||
390 | return ip_local_out(skb); | |
391 | ||
392 | no_route: | |
393 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); | |
394 | kfree_skb(skb); | |
395 | return -EHOSTUNREACH; | |
396 | } | |
397 | ||
398 | ||
399 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
400 | { | |
401 | to->pkt_type = from->pkt_type; | |
402 | to->priority = from->priority; | |
403 | to->protocol = from->protocol; | |
404 | dst_release(to->dst); | |
405 | to->dst = dst_clone(from->dst); | |
406 | to->dev = from->dev; | |
407 | to->mark = from->mark; | |
408 | ||
409 | /* Copy the flags to each fragment. */ | |
410 | IPCB(to)->flags = IPCB(from)->flags; | |
411 | ||
412 | #ifdef CONFIG_NET_SCHED | |
413 | to->tc_index = from->tc_index; | |
414 | #endif | |
415 | nf_copy(to, from); | |
416 | #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ | |
417 | defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) | |
418 | to->nf_trace = from->nf_trace; | |
419 | #endif | |
420 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) | |
421 | to->ipvs_property = from->ipvs_property; | |
422 | #endif | |
423 | skb_copy_secmark(to, from); | |
424 | } | |
425 | ||
426 | /* | |
427 | * This IP datagram is too large to be sent in one piece. Break it up into | |
428 | * smaller pieces (each of size equal to IP header plus | |
429 | * a block of the data of the original IP data part) that will yet fit in a | |
430 | * single device frame, and queue such a frame for sending. | |
431 | */ | |
432 | ||
433 | int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) | |
434 | { | |
435 | struct iphdr *iph; | |
436 | int raw = 0; | |
437 | int ptr; | |
438 | struct net_device *dev; | |
439 | struct sk_buff *skb2; | |
440 | unsigned int mtu, hlen, left, len, ll_rs, pad; | |
441 | int offset; | |
442 | __be16 not_last_frag; | |
443 | struct rtable *rt = skb->rtable; | |
444 | int err = 0; | |
445 | ||
446 | dev = rt->u.dst.dev; | |
447 | ||
448 | /* | |
449 | * Point into the IP datagram header. | |
450 | */ | |
451 | ||
452 | iph = ip_hdr(skb); | |
453 | ||
454 | if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { | |
455 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
456 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, | |
457 | htonl(ip_skb_dst_mtu(skb))); | |
458 | kfree_skb(skb); | |
459 | return -EMSGSIZE; | |
460 | } | |
461 | ||
462 | /* | |
463 | * Setup starting values. | |
464 | */ | |
465 | ||
466 | hlen = iph->ihl * 4; | |
467 | mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ | |
468 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; | |
469 | ||
470 | /* When frag_list is given, use it. First, check its validity: | |
471 | * some transformers could create wrong frag_list or break existing | |
472 | * one, it is not prohibited. In this case fall back to copying. | |
473 | * | |
474 | * LATER: this step can be merged to real generation of fragments, | |
475 | * we can switch to copy when see the first bad fragment. | |
476 | */ | |
477 | if (skb_shinfo(skb)->frag_list) { | |
478 | struct sk_buff *frag; | |
479 | int first_len = skb_pagelen(skb); | |
480 | int truesizes = 0; | |
481 | ||
482 | if (first_len - hlen > mtu || | |
483 | ((first_len - hlen) & 7) || | |
484 | (iph->frag_off & htons(IP_MF|IP_OFFSET)) || | |
485 | skb_cloned(skb)) | |
486 | goto slow_path; | |
487 | ||
488 | for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { | |
489 | /* Correct geometry. */ | |
490 | if (frag->len > mtu || | |
491 | ((frag->len & 7) && frag->next) || | |
492 | skb_headroom(frag) < hlen) | |
493 | goto slow_path; | |
494 | ||
495 | /* Partially cloned skb? */ | |
496 | if (skb_shared(frag)) | |
497 | goto slow_path; | |
498 | ||
499 | BUG_ON(frag->sk); | |
500 | if (skb->sk) { | |
501 | sock_hold(skb->sk); | |
502 | frag->sk = skb->sk; | |
503 | frag->destructor = sock_wfree; | |
504 | truesizes += frag->truesize; | |
505 | } | |
506 | } | |
507 | ||
508 | /* Everything is OK. Generate! */ | |
509 | ||
510 | err = 0; | |
511 | offset = 0; | |
512 | frag = skb_shinfo(skb)->frag_list; | |
513 | skb_shinfo(skb)->frag_list = NULL; | |
514 | skb->data_len = first_len - skb_headlen(skb); | |
515 | skb->truesize -= truesizes; | |
516 | skb->len = first_len; | |
517 | iph->tot_len = htons(first_len); | |
518 | iph->frag_off = htons(IP_MF); | |
519 | ip_send_check(iph); | |
520 | ||
521 | for (;;) { | |
522 | /* Prepare header of the next frame, | |
523 | * before previous one went down. */ | |
524 | if (frag) { | |
525 | frag->ip_summed = CHECKSUM_NONE; | |
526 | skb_reset_transport_header(frag); | |
527 | __skb_push(frag, hlen); | |
528 | skb_reset_network_header(frag); | |
529 | memcpy(skb_network_header(frag), iph, hlen); | |
530 | iph = ip_hdr(frag); | |
531 | iph->tot_len = htons(frag->len); | |
532 | ip_copy_metadata(frag, skb); | |
533 | if (offset == 0) | |
534 | ip_options_fragment(frag); | |
535 | offset += skb->len - hlen; | |
536 | iph->frag_off = htons(offset>>3); | |
537 | if (frag->next != NULL) | |
538 | iph->frag_off |= htons(IP_MF); | |
539 | /* Ready, complete checksum */ | |
540 | ip_send_check(iph); | |
541 | } | |
542 | ||
543 | err = output(skb); | |
544 | ||
545 | if (!err) | |
546 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); | |
547 | if (err || !frag) | |
548 | break; | |
549 | ||
550 | skb = frag; | |
551 | frag = skb->next; | |
552 | skb->next = NULL; | |
553 | } | |
554 | ||
555 | if (err == 0) { | |
556 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); | |
557 | return 0; | |
558 | } | |
559 | ||
560 | while (frag) { | |
561 | skb = frag->next; | |
562 | kfree_skb(frag); | |
563 | frag = skb; | |
564 | } | |
565 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
566 | return err; | |
567 | } | |
568 | ||
569 | slow_path: | |
570 | left = skb->len - hlen; /* Space per frame */ | |
571 | ptr = raw + hlen; /* Where to start from */ | |
572 | ||
573 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, | |
574 | * we need to make room for the encapsulating header | |
575 | */ | |
576 | pad = nf_bridge_pad(skb); | |
577 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad); | |
578 | mtu -= pad; | |
579 | ||
580 | /* | |
581 | * Fragment the datagram. | |
582 | */ | |
583 | ||
584 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
585 | not_last_frag = iph->frag_off & htons(IP_MF); | |
586 | ||
587 | /* | |
588 | * Keep copying data until we run out. | |
589 | */ | |
590 | ||
591 | while (left > 0) { | |
592 | len = left; | |
593 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
594 | if (len > mtu) | |
595 | len = mtu; | |
596 | /* IF: we are not sending upto and including the packet end | |
597 | then align the next start on an eight byte boundary */ | |
598 | if (len < left) { | |
599 | len &= ~7; | |
600 | } | |
601 | /* | |
602 | * Allocate buffer. | |
603 | */ | |
604 | ||
605 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { | |
606 | NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); | |
607 | err = -ENOMEM; | |
608 | goto fail; | |
609 | } | |
610 | ||
611 | /* | |
612 | * Set up data on packet | |
613 | */ | |
614 | ||
615 | ip_copy_metadata(skb2, skb); | |
616 | skb_reserve(skb2, ll_rs); | |
617 | skb_put(skb2, len + hlen); | |
618 | skb_reset_network_header(skb2); | |
619 | skb2->transport_header = skb2->network_header + hlen; | |
620 | ||
621 | /* | |
622 | * Charge the memory for the fragment to any owner | |
623 | * it might possess | |
624 | */ | |
625 | ||
626 | if (skb->sk) | |
627 | skb_set_owner_w(skb2, skb->sk); | |
628 | ||
629 | /* | |
630 | * Copy the packet header into the new buffer. | |
631 | */ | |
632 | ||
633 | skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); | |
634 | ||
635 | /* | |
636 | * Copy a block of the IP datagram. | |
637 | */ | |
638 | if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) | |
639 | BUG(); | |
640 | left -= len; | |
641 | ||
642 | /* | |
643 | * Fill in the new header fields. | |
644 | */ | |
645 | iph = ip_hdr(skb2); | |
646 | iph->frag_off = htons((offset >> 3)); | |
647 | ||
648 | /* ANK: dirty, but effective trick. Upgrade options only if | |
649 | * the segment to be fragmented was THE FIRST (otherwise, | |
650 | * options are already fixed) and make it ONCE | |
651 | * on the initial skb, so that all the following fragments | |
652 | * will inherit fixed options. | |
653 | */ | |
654 | if (offset == 0) | |
655 | ip_options_fragment(skb); | |
656 | ||
657 | /* | |
658 | * Added AC : If we are fragmenting a fragment that's not the | |
659 | * last fragment then keep MF on each bit | |
660 | */ | |
661 | if (left > 0 || not_last_frag) | |
662 | iph->frag_off |= htons(IP_MF); | |
663 | ptr += len; | |
664 | offset += len; | |
665 | ||
666 | /* | |
667 | * Put this fragment into the sending queue. | |
668 | */ | |
669 | iph->tot_len = htons(len + hlen); | |
670 | ||
671 | ip_send_check(iph); | |
672 | ||
673 | err = output(skb2); | |
674 | if (err) | |
675 | goto fail; | |
676 | ||
677 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); | |
678 | } | |
679 | kfree_skb(skb); | |
680 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); | |
681 | return err; | |
682 | ||
683 | fail: | |
684 | kfree_skb(skb); | |
685 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
686 | return err; | |
687 | } | |
688 | ||
689 | EXPORT_SYMBOL(ip_fragment); | |
690 | ||
691 | int | |
692 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
693 | { | |
694 | struct iovec *iov = from; | |
695 | ||
696 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
697 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) | |
698 | return -EFAULT; | |
699 | } else { | |
700 | __wsum csum = 0; | |
701 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) | |
702 | return -EFAULT; | |
703 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
704 | } | |
705 | return 0; | |
706 | } | |
707 | ||
708 | static inline __wsum | |
709 | csum_page(struct page *page, int offset, int copy) | |
710 | { | |
711 | char *kaddr; | |
712 | __wsum csum; | |
713 | kaddr = kmap(page); | |
714 | csum = csum_partial(kaddr + offset, copy, 0); | |
715 | kunmap(page); | |
716 | return csum; | |
717 | } | |
718 | ||
719 | static inline int ip_ufo_append_data(struct sock *sk, | |
720 | int getfrag(void *from, char *to, int offset, int len, | |
721 | int odd, struct sk_buff *skb), | |
722 | void *from, int length, int hh_len, int fragheaderlen, | |
723 | int transhdrlen, int mtu, unsigned int flags) | |
724 | { | |
725 | struct sk_buff *skb; | |
726 | int err; | |
727 | ||
728 | /* There is support for UDP fragmentation offload by network | |
729 | * device, so create one single skb packet containing complete | |
730 | * udp datagram | |
731 | */ | |
732 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { | |
733 | skb = sock_alloc_send_skb(sk, | |
734 | hh_len + fragheaderlen + transhdrlen + 20, | |
735 | (flags & MSG_DONTWAIT), &err); | |
736 | ||
737 | if (skb == NULL) | |
738 | return err; | |
739 | ||
740 | /* reserve space for Hardware header */ | |
741 | skb_reserve(skb, hh_len); | |
742 | ||
743 | /* create space for UDP/IP header */ | |
744 | skb_put(skb, fragheaderlen + transhdrlen); | |
745 | ||
746 | /* initialize network header pointer */ | |
747 | skb_reset_network_header(skb); | |
748 | ||
749 | /* initialize protocol header pointer */ | |
750 | skb->transport_header = skb->network_header + fragheaderlen; | |
751 | ||
752 | skb->ip_summed = CHECKSUM_PARTIAL; | |
753 | skb->csum = 0; | |
754 | sk->sk_sndmsg_off = 0; | |
755 | ||
756 | /* specify the length of each IP datagram fragment */ | |
757 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; | |
758 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
759 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
760 | } | |
761 | ||
762 | return skb_append_datato_frags(sk, skb, getfrag, from, | |
763 | (length - transhdrlen)); | |
764 | } | |
765 | ||
766 | /* | |
767 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
768 | * from many pieces of data. Each pieces will be holded on the socket | |
769 | * until ip_push_pending_frames() is called. Each piece can be a page | |
770 | * or non-page data. | |
771 | * | |
772 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
773 | * this interface potentially. | |
774 | * | |
775 | * LATER: length must be adjusted by pad at tail, when it is required. | |
776 | */ | |
777 | int ip_append_data(struct sock *sk, | |
778 | int getfrag(void *from, char *to, int offset, int len, | |
779 | int odd, struct sk_buff *skb), | |
780 | void *from, int length, int transhdrlen, | |
781 | struct ipcm_cookie *ipc, struct rtable *rt, | |
782 | unsigned int flags) | |
783 | { | |
784 | struct inet_sock *inet = inet_sk(sk); | |
785 | struct sk_buff *skb; | |
786 | ||
787 | struct ip_options *opt = NULL; | |
788 | int hh_len; | |
789 | int exthdrlen; | |
790 | int mtu; | |
791 | int copy; | |
792 | int err; | |
793 | int offset = 0; | |
794 | unsigned int maxfraglen, fragheaderlen; | |
795 | int csummode = CHECKSUM_NONE; | |
796 | ||
797 | if (flags&MSG_PROBE) | |
798 | return 0; | |
799 | ||
800 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
801 | /* | |
802 | * setup for corking. | |
803 | */ | |
804 | opt = ipc->opt; | |
805 | if (opt) { | |
806 | if (inet->cork.opt == NULL) { | |
807 | inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); | |
808 | if (unlikely(inet->cork.opt == NULL)) | |
809 | return -ENOBUFS; | |
810 | } | |
811 | memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); | |
812 | inet->cork.flags |= IPCORK_OPT; | |
813 | inet->cork.addr = ipc->addr; | |
814 | } | |
815 | dst_hold(&rt->u.dst); | |
816 | inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? | |
817 | rt->u.dst.dev->mtu : | |
818 | dst_mtu(rt->u.dst.path); | |
819 | inet->cork.dst = &rt->u.dst; | |
820 | inet->cork.length = 0; | |
821 | sk->sk_sndmsg_page = NULL; | |
822 | sk->sk_sndmsg_off = 0; | |
823 | if ((exthdrlen = rt->u.dst.header_len) != 0) { | |
824 | length += exthdrlen; | |
825 | transhdrlen += exthdrlen; | |
826 | } | |
827 | } else { | |
828 | rt = (struct rtable *)inet->cork.dst; | |
829 | if (inet->cork.flags & IPCORK_OPT) | |
830 | opt = inet->cork.opt; | |
831 | ||
832 | transhdrlen = 0; | |
833 | exthdrlen = 0; | |
834 | mtu = inet->cork.fragsize; | |
835 | } | |
836 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
837 | ||
838 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
839 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
840 | ||
841 | if (inet->cork.length + length > 0xFFFF - fragheaderlen) { | |
842 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); | |
843 | return -EMSGSIZE; | |
844 | } | |
845 | ||
846 | /* | |
847 | * transhdrlen > 0 means that this is the first fragment and we wish | |
848 | * it won't be fragmented in the future. | |
849 | */ | |
850 | if (transhdrlen && | |
851 | length + fragheaderlen <= mtu && | |
852 | rt->u.dst.dev->features & NETIF_F_V4_CSUM && | |
853 | !exthdrlen) | |
854 | csummode = CHECKSUM_PARTIAL; | |
855 | ||
856 | inet->cork.length += length; | |
857 | if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) && | |
858 | (sk->sk_protocol == IPPROTO_UDP) && | |
859 | (rt->u.dst.dev->features & NETIF_F_UFO)) { | |
860 | err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, | |
861 | fragheaderlen, transhdrlen, mtu, | |
862 | flags); | |
863 | if (err) | |
864 | goto error; | |
865 | return 0; | |
866 | } | |
867 | ||
868 | /* So, what's going on in the loop below? | |
869 | * | |
870 | * We use calculated fragment length to generate chained skb, | |
871 | * each of segments is IP fragment ready for sending to network after | |
872 | * adding appropriate IP header. | |
873 | */ | |
874 | ||
875 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
876 | goto alloc_new_skb; | |
877 | ||
878 | while (length > 0) { | |
879 | /* Check if the remaining data fits into current packet. */ | |
880 | copy = mtu - skb->len; | |
881 | if (copy < length) | |
882 | copy = maxfraglen - skb->len; | |
883 | if (copy <= 0) { | |
884 | char *data; | |
885 | unsigned int datalen; | |
886 | unsigned int fraglen; | |
887 | unsigned int fraggap; | |
888 | unsigned int alloclen; | |
889 | struct sk_buff *skb_prev; | |
890 | alloc_new_skb: | |
891 | skb_prev = skb; | |
892 | if (skb_prev) | |
893 | fraggap = skb_prev->len - maxfraglen; | |
894 | else | |
895 | fraggap = 0; | |
896 | ||
897 | /* | |
898 | * If remaining data exceeds the mtu, | |
899 | * we know we need more fragment(s). | |
900 | */ | |
901 | datalen = length + fraggap; | |
902 | if (datalen > mtu - fragheaderlen) | |
903 | datalen = maxfraglen - fragheaderlen; | |
904 | fraglen = datalen + fragheaderlen; | |
905 | ||
906 | if ((flags & MSG_MORE) && | |
907 | !(rt->u.dst.dev->features&NETIF_F_SG)) | |
908 | alloclen = mtu; | |
909 | else | |
910 | alloclen = datalen + fragheaderlen; | |
911 | ||
912 | /* The last fragment gets additional space at tail. | |
913 | * Note, with MSG_MORE we overallocate on fragments, | |
914 | * because we have no idea what fragment will be | |
915 | * the last. | |
916 | */ | |
917 | if (datalen == length + fraggap) | |
918 | alloclen += rt->u.dst.trailer_len; | |
919 | ||
920 | if (transhdrlen) { | |
921 | skb = sock_alloc_send_skb(sk, | |
922 | alloclen + hh_len + 15, | |
923 | (flags & MSG_DONTWAIT), &err); | |
924 | } else { | |
925 | skb = NULL; | |
926 | if (atomic_read(&sk->sk_wmem_alloc) <= | |
927 | 2 * sk->sk_sndbuf) | |
928 | skb = sock_wmalloc(sk, | |
929 | alloclen + hh_len + 15, 1, | |
930 | sk->sk_allocation); | |
931 | if (unlikely(skb == NULL)) | |
932 | err = -ENOBUFS; | |
933 | } | |
934 | if (skb == NULL) | |
935 | goto error; | |
936 | ||
937 | /* | |
938 | * Fill in the control structures | |
939 | */ | |
940 | skb->ip_summed = csummode; | |
941 | skb->csum = 0; | |
942 | skb_reserve(skb, hh_len); | |
943 | ||
944 | /* | |
945 | * Find where to start putting bytes. | |
946 | */ | |
947 | data = skb_put(skb, fraglen); | |
948 | skb_set_network_header(skb, exthdrlen); | |
949 | skb->transport_header = (skb->network_header + | |
950 | fragheaderlen); | |
951 | data += fragheaderlen; | |
952 | ||
953 | if (fraggap) { | |
954 | skb->csum = skb_copy_and_csum_bits( | |
955 | skb_prev, maxfraglen, | |
956 | data + transhdrlen, fraggap, 0); | |
957 | skb_prev->csum = csum_sub(skb_prev->csum, | |
958 | skb->csum); | |
959 | data += fraggap; | |
960 | pskb_trim_unique(skb_prev, maxfraglen); | |
961 | } | |
962 | ||
963 | copy = datalen - transhdrlen - fraggap; | |
964 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
965 | err = -EFAULT; | |
966 | kfree_skb(skb); | |
967 | goto error; | |
968 | } | |
969 | ||
970 | offset += copy; | |
971 | length -= datalen - fraggap; | |
972 | transhdrlen = 0; | |
973 | exthdrlen = 0; | |
974 | csummode = CHECKSUM_NONE; | |
975 | ||
976 | /* | |
977 | * Put the packet on the pending queue. | |
978 | */ | |
979 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
980 | continue; | |
981 | } | |
982 | ||
983 | if (copy > length) | |
984 | copy = length; | |
985 | ||
986 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) { | |
987 | unsigned int off; | |
988 | ||
989 | off = skb->len; | |
990 | if (getfrag(from, skb_put(skb, copy), | |
991 | offset, copy, off, skb) < 0) { | |
992 | __skb_trim(skb, off); | |
993 | err = -EFAULT; | |
994 | goto error; | |
995 | } | |
996 | } else { | |
997 | int i = skb_shinfo(skb)->nr_frags; | |
998 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; | |
999 | struct page *page = sk->sk_sndmsg_page; | |
1000 | int off = sk->sk_sndmsg_off; | |
1001 | unsigned int left; | |
1002 | ||
1003 | if (page && (left = PAGE_SIZE - off) > 0) { | |
1004 | if (copy >= left) | |
1005 | copy = left; | |
1006 | if (page != frag->page) { | |
1007 | if (i == MAX_SKB_FRAGS) { | |
1008 | err = -EMSGSIZE; | |
1009 | goto error; | |
1010 | } | |
1011 | get_page(page); | |
1012 | skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); | |
1013 | frag = &skb_shinfo(skb)->frags[i]; | |
1014 | } | |
1015 | } else if (i < MAX_SKB_FRAGS) { | |
1016 | if (copy > PAGE_SIZE) | |
1017 | copy = PAGE_SIZE; | |
1018 | page = alloc_pages(sk->sk_allocation, 0); | |
1019 | if (page == NULL) { | |
1020 | err = -ENOMEM; | |
1021 | goto error; | |
1022 | } | |
1023 | sk->sk_sndmsg_page = page; | |
1024 | sk->sk_sndmsg_off = 0; | |
1025 | ||
1026 | skb_fill_page_desc(skb, i, page, 0, 0); | |
1027 | frag = &skb_shinfo(skb)->frags[i]; | |
1028 | } else { | |
1029 | err = -EMSGSIZE; | |
1030 | goto error; | |
1031 | } | |
1032 | if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { | |
1033 | err = -EFAULT; | |
1034 | goto error; | |
1035 | } | |
1036 | sk->sk_sndmsg_off += copy; | |
1037 | frag->size += copy; | |
1038 | skb->len += copy; | |
1039 | skb->data_len += copy; | |
1040 | skb->truesize += copy; | |
1041 | atomic_add(copy, &sk->sk_wmem_alloc); | |
1042 | } | |
1043 | offset += copy; | |
1044 | length -= copy; | |
1045 | } | |
1046 | ||
1047 | return 0; | |
1048 | ||
1049 | error: | |
1050 | inet->cork.length -= length; | |
1051 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1052 | return err; | |
1053 | } | |
1054 | ||
1055 | ssize_t ip_append_page(struct sock *sk, struct page *page, | |
1056 | int offset, size_t size, int flags) | |
1057 | { | |
1058 | struct inet_sock *inet = inet_sk(sk); | |
1059 | struct sk_buff *skb; | |
1060 | struct rtable *rt; | |
1061 | struct ip_options *opt = NULL; | |
1062 | int hh_len; | |
1063 | int mtu; | |
1064 | int len; | |
1065 | int err; | |
1066 | unsigned int maxfraglen, fragheaderlen, fraggap; | |
1067 | ||
1068 | if (inet->hdrincl) | |
1069 | return -EPERM; | |
1070 | ||
1071 | if (flags&MSG_PROBE) | |
1072 | return 0; | |
1073 | ||
1074 | if (skb_queue_empty(&sk->sk_write_queue)) | |
1075 | return -EINVAL; | |
1076 | ||
1077 | rt = (struct rtable *)inet->cork.dst; | |
1078 | if (inet->cork.flags & IPCORK_OPT) | |
1079 | opt = inet->cork.opt; | |
1080 | ||
1081 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) | |
1082 | return -EOPNOTSUPP; | |
1083 | ||
1084 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
1085 | mtu = inet->cork.fragsize; | |
1086 | ||
1087 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1088 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1089 | ||
1090 | if (inet->cork.length + size > 0xFFFF - fragheaderlen) { | |
1091 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); | |
1092 | return -EMSGSIZE; | |
1093 | } | |
1094 | ||
1095 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
1096 | return -EINVAL; | |
1097 | ||
1098 | inet->cork.length += size; | |
1099 | if ((sk->sk_protocol == IPPROTO_UDP) && | |
1100 | (rt->u.dst.dev->features & NETIF_F_UFO)) { | |
1101 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; | |
1102 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
1103 | } | |
1104 | ||
1105 | ||
1106 | while (size > 0) { | |
1107 | int i; | |
1108 | ||
1109 | if (skb_is_gso(skb)) | |
1110 | len = size; | |
1111 | else { | |
1112 | ||
1113 | /* Check if the remaining data fits into current packet. */ | |
1114 | len = mtu - skb->len; | |
1115 | if (len < size) | |
1116 | len = maxfraglen - skb->len; | |
1117 | } | |
1118 | if (len <= 0) { | |
1119 | struct sk_buff *skb_prev; | |
1120 | int alloclen; | |
1121 | ||
1122 | skb_prev = skb; | |
1123 | fraggap = skb_prev->len - maxfraglen; | |
1124 | ||
1125 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1126 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1127 | if (unlikely(!skb)) { | |
1128 | err = -ENOBUFS; | |
1129 | goto error; | |
1130 | } | |
1131 | ||
1132 | /* | |
1133 | * Fill in the control structures | |
1134 | */ | |
1135 | skb->ip_summed = CHECKSUM_NONE; | |
1136 | skb->csum = 0; | |
1137 | skb_reserve(skb, hh_len); | |
1138 | ||
1139 | /* | |
1140 | * Find where to start putting bytes. | |
1141 | */ | |
1142 | skb_put(skb, fragheaderlen + fraggap); | |
1143 | skb_reset_network_header(skb); | |
1144 | skb->transport_header = (skb->network_header + | |
1145 | fragheaderlen); | |
1146 | if (fraggap) { | |
1147 | skb->csum = skb_copy_and_csum_bits(skb_prev, | |
1148 | maxfraglen, | |
1149 | skb_transport_header(skb), | |
1150 | fraggap, 0); | |
1151 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1152 | skb->csum); | |
1153 | pskb_trim_unique(skb_prev, maxfraglen); | |
1154 | } | |
1155 | ||
1156 | /* | |
1157 | * Put the packet on the pending queue. | |
1158 | */ | |
1159 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1160 | continue; | |
1161 | } | |
1162 | ||
1163 | i = skb_shinfo(skb)->nr_frags; | |
1164 | if (len > size) | |
1165 | len = size; | |
1166 | if (skb_can_coalesce(skb, i, page, offset)) { | |
1167 | skb_shinfo(skb)->frags[i-1].size += len; | |
1168 | } else if (i < MAX_SKB_FRAGS) { | |
1169 | get_page(page); | |
1170 | skb_fill_page_desc(skb, i, page, offset, len); | |
1171 | } else { | |
1172 | err = -EMSGSIZE; | |
1173 | goto error; | |
1174 | } | |
1175 | ||
1176 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1177 | __wsum csum; | |
1178 | csum = csum_page(page, offset, len); | |
1179 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1180 | } | |
1181 | ||
1182 | skb->len += len; | |
1183 | skb->data_len += len; | |
1184 | skb->truesize += len; | |
1185 | atomic_add(len, &sk->sk_wmem_alloc); | |
1186 | offset += len; | |
1187 | size -= len; | |
1188 | } | |
1189 | return 0; | |
1190 | ||
1191 | error: | |
1192 | inet->cork.length -= size; | |
1193 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1194 | return err; | |
1195 | } | |
1196 | ||
1197 | static void ip_cork_release(struct inet_sock *inet) | |
1198 | { | |
1199 | inet->cork.flags &= ~IPCORK_OPT; | |
1200 | kfree(inet->cork.opt); | |
1201 | inet->cork.opt = NULL; | |
1202 | dst_release(inet->cork.dst); | |
1203 | inet->cork.dst = NULL; | |
1204 | } | |
1205 | ||
1206 | /* | |
1207 | * Combined all pending IP fragments on the socket as one IP datagram | |
1208 | * and push them out. | |
1209 | */ | |
1210 | int ip_push_pending_frames(struct sock *sk) | |
1211 | { | |
1212 | struct sk_buff *skb, *tmp_skb; | |
1213 | struct sk_buff **tail_skb; | |
1214 | struct inet_sock *inet = inet_sk(sk); | |
1215 | struct net *net = sock_net(sk); | |
1216 | struct ip_options *opt = NULL; | |
1217 | struct rtable *rt = (struct rtable *)inet->cork.dst; | |
1218 | struct iphdr *iph; | |
1219 | __be16 df = 0; | |
1220 | __u8 ttl; | |
1221 | int err = 0; | |
1222 | ||
1223 | if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) | |
1224 | goto out; | |
1225 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1226 | ||
1227 | /* move skb->data to ip header from ext header */ | |
1228 | if (skb->data < skb_network_header(skb)) | |
1229 | __skb_pull(skb, skb_network_offset(skb)); | |
1230 | while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { | |
1231 | __skb_pull(tmp_skb, skb_network_header_len(skb)); | |
1232 | *tail_skb = tmp_skb; | |
1233 | tail_skb = &(tmp_skb->next); | |
1234 | skb->len += tmp_skb->len; | |
1235 | skb->data_len += tmp_skb->len; | |
1236 | skb->truesize += tmp_skb->truesize; | |
1237 | __sock_put(tmp_skb->sk); | |
1238 | tmp_skb->destructor = NULL; | |
1239 | tmp_skb->sk = NULL; | |
1240 | } | |
1241 | ||
1242 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1243 | * to fragment the frame generated here. No matter, what transforms | |
1244 | * how transforms change size of the packet, it will come out. | |
1245 | */ | |
1246 | if (inet->pmtudisc < IP_PMTUDISC_DO) | |
1247 | skb->local_df = 1; | |
1248 | ||
1249 | /* DF bit is set when we want to see DF on outgoing frames. | |
1250 | * If local_df is set too, we still allow to fragment this frame | |
1251 | * locally. */ | |
1252 | if (inet->pmtudisc >= IP_PMTUDISC_DO || | |
1253 | (skb->len <= dst_mtu(&rt->u.dst) && | |
1254 | ip_dont_fragment(sk, &rt->u.dst))) | |
1255 | df = htons(IP_DF); | |
1256 | ||
1257 | if (inet->cork.flags & IPCORK_OPT) | |
1258 | opt = inet->cork.opt; | |
1259 | ||
1260 | if (rt->rt_type == RTN_MULTICAST) | |
1261 | ttl = inet->mc_ttl; | |
1262 | else | |
1263 | ttl = ip_select_ttl(inet, &rt->u.dst); | |
1264 | ||
1265 | iph = (struct iphdr *)skb->data; | |
1266 | iph->version = 4; | |
1267 | iph->ihl = 5; | |
1268 | if (opt) { | |
1269 | iph->ihl += opt->optlen>>2; | |
1270 | ip_options_build(skb, opt, inet->cork.addr, rt, 0); | |
1271 | } | |
1272 | iph->tos = inet->tos; | |
1273 | iph->frag_off = df; | |
1274 | ip_select_ident(iph, &rt->u.dst, sk); | |
1275 | iph->ttl = ttl; | |
1276 | iph->protocol = sk->sk_protocol; | |
1277 | iph->saddr = rt->rt_src; | |
1278 | iph->daddr = rt->rt_dst; | |
1279 | ||
1280 | skb->priority = sk->sk_priority; | |
1281 | skb->mark = sk->sk_mark; | |
1282 | skb->dst = dst_clone(&rt->u.dst); | |
1283 | ||
1284 | if (iph->protocol == IPPROTO_ICMP) | |
1285 | icmp_out_count(net, ((struct icmphdr *) | |
1286 | skb_transport_header(skb))->type); | |
1287 | ||
1288 | /* Netfilter gets whole the not fragmented skb. */ | |
1289 | err = ip_local_out(skb); | |
1290 | if (err) { | |
1291 | if (err > 0) | |
1292 | err = inet->recverr ? net_xmit_errno(err) : 0; | |
1293 | if (err) | |
1294 | goto error; | |
1295 | } | |
1296 | ||
1297 | out: | |
1298 | ip_cork_release(inet); | |
1299 | return err; | |
1300 | ||
1301 | error: | |
1302 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); | |
1303 | goto out; | |
1304 | } | |
1305 | ||
1306 | /* | |
1307 | * Throw away all pending data on the socket. | |
1308 | */ | |
1309 | void ip_flush_pending_frames(struct sock *sk) | |
1310 | { | |
1311 | struct sk_buff *skb; | |
1312 | ||
1313 | while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) | |
1314 | kfree_skb(skb); | |
1315 | ||
1316 | ip_cork_release(inet_sk(sk)); | |
1317 | } | |
1318 | ||
1319 | ||
1320 | /* | |
1321 | * Fetch data from kernel space and fill in checksum if needed. | |
1322 | */ | |
1323 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, | |
1324 | int len, int odd, struct sk_buff *skb) | |
1325 | { | |
1326 | __wsum csum; | |
1327 | ||
1328 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); | |
1329 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
1330 | return 0; | |
1331 | } | |
1332 | ||
1333 | /* | |
1334 | * Generic function to send a packet as reply to another packet. | |
1335 | * Used to send TCP resets so far. ICMP should use this function too. | |
1336 | * | |
1337 | * Should run single threaded per socket because it uses the sock | |
1338 | * structure to pass arguments. | |
1339 | */ | |
1340 | void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, | |
1341 | unsigned int len) | |
1342 | { | |
1343 | struct inet_sock *inet = inet_sk(sk); | |
1344 | struct { | |
1345 | struct ip_options opt; | |
1346 | char data[40]; | |
1347 | } replyopts; | |
1348 | struct ipcm_cookie ipc; | |
1349 | __be32 daddr; | |
1350 | struct rtable *rt = skb->rtable; | |
1351 | ||
1352 | if (ip_options_echo(&replyopts.opt, skb)) | |
1353 | return; | |
1354 | ||
1355 | daddr = ipc.addr = rt->rt_src; | |
1356 | ipc.opt = NULL; | |
1357 | ||
1358 | if (replyopts.opt.optlen) { | |
1359 | ipc.opt = &replyopts.opt; | |
1360 | ||
1361 | if (ipc.opt->srr) | |
1362 | daddr = replyopts.opt.faddr; | |
1363 | } | |
1364 | ||
1365 | { | |
1366 | struct flowi fl = { .oif = arg->bound_dev_if, | |
1367 | .nl_u = { .ip4_u = | |
1368 | { .daddr = daddr, | |
1369 | .saddr = rt->rt_spec_dst, | |
1370 | .tos = RT_TOS(ip_hdr(skb)->tos) } }, | |
1371 | /* Not quite clean, but right. */ | |
1372 | .uli_u = { .ports = | |
1373 | { .sport = tcp_hdr(skb)->dest, | |
1374 | .dport = tcp_hdr(skb)->source } }, | |
1375 | .proto = sk->sk_protocol, | |
1376 | .flags = ip_reply_arg_flowi_flags(arg) }; | |
1377 | security_skb_classify_flow(skb, &fl); | |
1378 | if (ip_route_output_key(sock_net(sk), &rt, &fl)) | |
1379 | return; | |
1380 | } | |
1381 | ||
1382 | /* And let IP do all the hard work. | |
1383 | ||
1384 | This chunk is not reenterable, hence spinlock. | |
1385 | Note that it uses the fact, that this function is called | |
1386 | with locally disabled BH and that sk cannot be already spinlocked. | |
1387 | */ | |
1388 | bh_lock_sock(sk); | |
1389 | inet->tos = ip_hdr(skb)->tos; | |
1390 | sk->sk_priority = skb->priority; | |
1391 | sk->sk_protocol = ip_hdr(skb)->protocol; | |
1392 | sk->sk_bound_dev_if = arg->bound_dev_if; | |
1393 | ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, | |
1394 | &ipc, rt, MSG_DONTWAIT); | |
1395 | if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { | |
1396 | if (arg->csumoffset >= 0) | |
1397 | *((__sum16 *)skb_transport_header(skb) + | |
1398 | arg->csumoffset) = csum_fold(csum_add(skb->csum, | |
1399 | arg->csum)); | |
1400 | skb->ip_summed = CHECKSUM_NONE; | |
1401 | ip_push_pending_frames(sk); | |
1402 | } | |
1403 | ||
1404 | bh_unlock_sock(sk); | |
1405 | ||
1406 | ip_rt_put(rt); | |
1407 | } | |
1408 | ||
1409 | void __init ip_init(void) | |
1410 | { | |
1411 | ip_rt_init(); | |
1412 | inet_initpeers(); | |
1413 | ||
1414 | #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) | |
1415 | igmp_mc_proc_init(); | |
1416 | #endif | |
1417 | } | |
1418 | ||
1419 | EXPORT_SYMBOL(ip_generic_getfrag); | |
1420 | EXPORT_SYMBOL(ip_queue_xmit); | |
1421 | EXPORT_SYMBOL(ip_send_check); |