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Commit | Line | Data |
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1da177e4 LT |
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 | * Version: $Id: ip_output.c,v 1.100 2002/02/01 22:01:03 davem Exp $ | |
9 | * | |
10 | * Authors: Ross Biro, <bir7@leland.Stanford.Edu> | |
11 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> | |
12 | * Donald Becker, <becker@super.org> | |
13 | * Alan Cox, <Alan.Cox@linux.org> | |
14 | * Richard Underwood | |
15 | * Stefan Becker, <stefanb@yello.ping.de> | |
16 | * Jorge Cwik, <jorge@laser.satlink.net> | |
17 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | |
18 | * Hirokazu Takahashi, <taka@valinux.co.jp> | |
19 | * | |
20 | * See ip_input.c for original log | |
21 | * | |
22 | * Fixes: | |
23 | * Alan Cox : Missing nonblock feature in ip_build_xmit. | |
24 | * Mike Kilburn : htons() missing in ip_build_xmit. | |
25 | * Bradford Johnson: Fix faulty handling of some frames when | |
26 | * no route is found. | |
27 | * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit | |
28 | * (in case if packet not accepted by | |
29 | * output firewall rules) | |
30 | * Mike McLagan : Routing by source | |
31 | * Alexey Kuznetsov: use new route cache | |
32 | * Andi Kleen: Fix broken PMTU recovery and remove | |
33 | * some redundant tests. | |
34 | * Vitaly E. Lavrov : Transparent proxy revived after year coma. | |
35 | * Andi Kleen : Replace ip_reply with ip_send_reply. | |
36 | * Andi Kleen : Split fast and slow ip_build_xmit path | |
37 | * for decreased register pressure on x86 | |
38 | * and more readibility. | |
39 | * Marc Boucher : When call_out_firewall returns FW_QUEUE, | |
40 | * silently drop skb instead of failing with -EPERM. | |
41 | * Detlev Wengorz : Copy protocol for fragments. | |
42 | * Hirokazu Takahashi: HW checksumming for outgoing UDP | |
43 | * datagrams. | |
44 | * Hirokazu Takahashi: sendfile() on UDP works now. | |
45 | */ | |
46 | ||
47 | #include <asm/uaccess.h> | |
48 | #include <asm/system.h> | |
49 | #include <linux/module.h> | |
50 | #include <linux/types.h> | |
51 | #include <linux/kernel.h> | |
52 | #include <linux/sched.h> | |
53 | #include <linux/mm.h> | |
54 | #include <linux/string.h> | |
55 | #include <linux/errno.h> | |
56 | #include <linux/config.h> | |
57 | ||
58 | #include <linux/socket.h> | |
59 | #include <linux/sockios.h> | |
60 | #include <linux/in.h> | |
61 | #include <linux/inet.h> | |
62 | #include <linux/netdevice.h> | |
63 | #include <linux/etherdevice.h> | |
64 | #include <linux/proc_fs.h> | |
65 | #include <linux/stat.h> | |
66 | #include <linux/init.h> | |
67 | ||
68 | #include <net/snmp.h> | |
69 | #include <net/ip.h> | |
70 | #include <net/protocol.h> | |
71 | #include <net/route.h> | |
72 | #include <net/tcp.h> | |
73 | #include <net/udp.h> | |
74 | #include <linux/skbuff.h> | |
75 | #include <net/sock.h> | |
76 | #include <net/arp.h> | |
77 | #include <net/icmp.h> | |
78 | #include <net/raw.h> | |
79 | #include <net/checksum.h> | |
80 | #include <net/inetpeer.h> | |
81 | #include <net/checksum.h> | |
82 | #include <linux/igmp.h> | |
83 | #include <linux/netfilter_ipv4.h> | |
84 | #include <linux/netfilter_bridge.h> | |
85 | #include <linux/mroute.h> | |
86 | #include <linux/netlink.h> | |
87 | ||
88 | /* | |
89 | * Shall we try to damage output packets if routing dev changes? | |
90 | */ | |
91 | ||
92 | int sysctl_ip_dynaddr; | |
93 | int sysctl_ip_default_ttl = IPDEFTTL; | |
94 | ||
95 | /* Generate a checksum for an outgoing IP datagram. */ | |
96 | __inline__ void ip_send_check(struct iphdr *iph) | |
97 | { | |
98 | iph->check = 0; | |
99 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
100 | } | |
101 | ||
102 | /* dev_loopback_xmit for use with netfilter. */ | |
103 | static int ip_dev_loopback_xmit(struct sk_buff *newskb) | |
104 | { | |
105 | newskb->mac.raw = newskb->data; | |
106 | __skb_pull(newskb, newskb->nh.raw - newskb->data); | |
107 | newskb->pkt_type = PACKET_LOOPBACK; | |
108 | newskb->ip_summed = CHECKSUM_UNNECESSARY; | |
109 | BUG_TRAP(newskb->dst); | |
110 | ||
111 | #ifdef CONFIG_NETFILTER_DEBUG | |
112 | nf_debug_ip_loopback_xmit(newskb); | |
113 | #endif | |
114 | netif_rx(newskb); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) | |
119 | { | |
120 | int ttl = inet->uc_ttl; | |
121 | ||
122 | if (ttl < 0) | |
123 | ttl = dst_metric(dst, RTAX_HOPLIMIT); | |
124 | return ttl; | |
125 | } | |
126 | ||
127 | /* | |
128 | * Add an ip header to a skbuff and send it out. | |
129 | * | |
130 | */ | |
131 | int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, | |
132 | u32 saddr, u32 daddr, struct ip_options *opt) | |
133 | { | |
134 | struct inet_sock *inet = inet_sk(sk); | |
135 | struct rtable *rt = (struct rtable *)skb->dst; | |
136 | struct iphdr *iph; | |
137 | ||
138 | /* Build the IP header. */ | |
139 | if (opt) | |
140 | iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); | |
141 | else | |
142 | iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); | |
143 | ||
144 | iph->version = 4; | |
145 | iph->ihl = 5; | |
146 | iph->tos = inet->tos; | |
147 | if (ip_dont_fragment(sk, &rt->u.dst)) | |
148 | iph->frag_off = htons(IP_DF); | |
149 | else | |
150 | iph->frag_off = 0; | |
151 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
152 | iph->daddr = rt->rt_dst; | |
153 | iph->saddr = rt->rt_src; | |
154 | iph->protocol = sk->sk_protocol; | |
155 | iph->tot_len = htons(skb->len); | |
156 | ip_select_ident(iph, &rt->u.dst, sk); | |
157 | skb->nh.iph = iph; | |
158 | ||
159 | if (opt && opt->optlen) { | |
160 | iph->ihl += opt->optlen>>2; | |
161 | ip_options_build(skb, opt, daddr, rt, 0); | |
162 | } | |
163 | ip_send_check(iph); | |
164 | ||
165 | skb->priority = sk->sk_priority; | |
166 | ||
167 | /* Send it out. */ | |
168 | return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, | |
169 | dst_output); | |
170 | } | |
171 | ||
172 | static inline int ip_finish_output2(struct sk_buff *skb) | |
173 | { | |
174 | struct dst_entry *dst = skb->dst; | |
175 | struct hh_cache *hh = dst->hh; | |
176 | struct net_device *dev = dst->dev; | |
177 | int hh_len = LL_RESERVED_SPACE(dev); | |
178 | ||
179 | /* Be paranoid, rather than too clever. */ | |
180 | if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) { | |
181 | struct sk_buff *skb2; | |
182 | ||
183 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
184 | if (skb2 == NULL) { | |
185 | kfree_skb(skb); | |
186 | return -ENOMEM; | |
187 | } | |
188 | if (skb->sk) | |
189 | skb_set_owner_w(skb2, skb->sk); | |
190 | kfree_skb(skb); | |
191 | skb = skb2; | |
192 | } | |
193 | ||
194 | #ifdef CONFIG_NETFILTER_DEBUG | |
195 | nf_debug_ip_finish_output2(skb); | |
196 | #endif /*CONFIG_NETFILTER_DEBUG*/ | |
197 | ||
198 | if (hh) { | |
199 | int hh_alen; | |
200 | ||
201 | read_lock_bh(&hh->hh_lock); | |
202 | hh_alen = HH_DATA_ALIGN(hh->hh_len); | |
203 | memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); | |
204 | read_unlock_bh(&hh->hh_lock); | |
205 | skb_push(skb, hh->hh_len); | |
206 | return hh->hh_output(skb); | |
207 | } else if (dst->neighbour) | |
208 | return dst->neighbour->output(skb); | |
209 | ||
210 | if (net_ratelimit()) | |
211 | printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); | |
212 | kfree_skb(skb); | |
213 | return -EINVAL; | |
214 | } | |
215 | ||
216 | int ip_finish_output(struct sk_buff *skb) | |
217 | { | |
218 | struct net_device *dev = skb->dst->dev; | |
219 | ||
220 | skb->dev = dev; | |
221 | skb->protocol = htons(ETH_P_IP); | |
222 | ||
223 | return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, | |
224 | ip_finish_output2); | |
225 | } | |
226 | ||
227 | int ip_mc_output(struct sk_buff *skb) | |
228 | { | |
229 | struct sock *sk = skb->sk; | |
230 | struct rtable *rt = (struct rtable*)skb->dst; | |
231 | struct net_device *dev = rt->u.dst.dev; | |
232 | ||
233 | /* | |
234 | * If the indicated interface is up and running, send the packet. | |
235 | */ | |
236 | IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); | |
237 | ||
238 | skb->dev = dev; | |
239 | skb->protocol = htons(ETH_P_IP); | |
240 | ||
241 | /* | |
242 | * Multicasts are looped back for other local users | |
243 | */ | |
244 | ||
245 | if (rt->rt_flags&RTCF_MULTICAST) { | |
246 | if ((!sk || inet_sk(sk)->mc_loop) | |
247 | #ifdef CONFIG_IP_MROUTE | |
248 | /* Small optimization: do not loopback not local frames, | |
249 | which returned after forwarding; they will be dropped | |
250 | by ip_mr_input in any case. | |
251 | Note, that local frames are looped back to be delivered | |
252 | to local recipients. | |
253 | ||
254 | This check is duplicated in ip_mr_input at the moment. | |
255 | */ | |
256 | && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) | |
257 | #endif | |
258 | ) { | |
259 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
260 | if (newskb) | |
261 | NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, | |
262 | newskb->dev, | |
263 | ip_dev_loopback_xmit); | |
264 | } | |
265 | ||
266 | /* Multicasts with ttl 0 must not go beyond the host */ | |
267 | ||
268 | if (skb->nh.iph->ttl == 0) { | |
269 | kfree_skb(skb); | |
270 | return 0; | |
271 | } | |
272 | } | |
273 | ||
274 | if (rt->rt_flags&RTCF_BROADCAST) { | |
275 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
276 | if (newskb) | |
277 | NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, | |
278 | newskb->dev, ip_dev_loopback_xmit); | |
279 | } | |
280 | ||
281 | if (skb->len > dst_mtu(&rt->u.dst)) | |
282 | return ip_fragment(skb, ip_finish_output); | |
283 | else | |
284 | return ip_finish_output(skb); | |
285 | } | |
286 | ||
287 | int ip_output(struct sk_buff *skb) | |
288 | { | |
289 | IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); | |
290 | ||
291 | if (skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->tso_size) | |
292 | return ip_fragment(skb, ip_finish_output); | |
293 | else | |
294 | return ip_finish_output(skb); | |
295 | } | |
296 | ||
297 | int ip_queue_xmit(struct sk_buff *skb, int ipfragok) | |
298 | { | |
299 | struct sock *sk = skb->sk; | |
300 | struct inet_sock *inet = inet_sk(sk); | |
301 | struct ip_options *opt = inet->opt; | |
302 | struct rtable *rt; | |
303 | struct iphdr *iph; | |
304 | ||
305 | /* Skip all of this if the packet is already routed, | |
306 | * f.e. by something like SCTP. | |
307 | */ | |
308 | rt = (struct rtable *) skb->dst; | |
309 | if (rt != NULL) | |
310 | goto packet_routed; | |
311 | ||
312 | /* Make sure we can route this packet. */ | |
313 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
314 | if (rt == NULL) { | |
315 | u32 daddr; | |
316 | ||
317 | /* Use correct destination address if we have options. */ | |
318 | daddr = inet->daddr; | |
319 | if(opt && opt->srr) | |
320 | daddr = opt->faddr; | |
321 | ||
322 | { | |
323 | struct flowi fl = { .oif = sk->sk_bound_dev_if, | |
324 | .nl_u = { .ip4_u = | |
325 | { .daddr = daddr, | |
326 | .saddr = inet->saddr, | |
327 | .tos = RT_CONN_FLAGS(sk) } }, | |
328 | .proto = sk->sk_protocol, | |
329 | .uli_u = { .ports = | |
330 | { .sport = inet->sport, | |
331 | .dport = inet->dport } } }; | |
332 | ||
333 | /* If this fails, retransmit mechanism of transport layer will | |
334 | * keep trying until route appears or the connection times | |
335 | * itself out. | |
336 | */ | |
337 | if (ip_route_output_flow(&rt, &fl, sk, 0)) | |
338 | goto no_route; | |
339 | } | |
340 | __sk_dst_set(sk, &rt->u.dst); | |
341 | tcp_v4_setup_caps(sk, &rt->u.dst); | |
342 | } | |
343 | skb->dst = dst_clone(&rt->u.dst); | |
344 | ||
345 | packet_routed: | |
346 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) | |
347 | goto no_route; | |
348 | ||
349 | /* OK, we know where to send it, allocate and build IP header. */ | |
350 | iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
351 | *((__u16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); | |
352 | iph->tot_len = htons(skb->len); | |
353 | if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) | |
354 | iph->frag_off = htons(IP_DF); | |
355 | else | |
356 | iph->frag_off = 0; | |
357 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
358 | iph->protocol = sk->sk_protocol; | |
359 | iph->saddr = rt->rt_src; | |
360 | iph->daddr = rt->rt_dst; | |
361 | skb->nh.iph = iph; | |
362 | /* Transport layer set skb->h.foo itself. */ | |
363 | ||
364 | if (opt && opt->optlen) { | |
365 | iph->ihl += opt->optlen >> 2; | |
366 | ip_options_build(skb, opt, inet->daddr, rt, 0); | |
367 | } | |
368 | ||
369 | ip_select_ident_more(iph, &rt->u.dst, sk, skb_shinfo(skb)->tso_segs); | |
370 | ||
371 | /* Add an IP checksum. */ | |
372 | ip_send_check(iph); | |
373 | ||
374 | skb->priority = sk->sk_priority; | |
375 | ||
376 | return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, | |
377 | dst_output); | |
378 | ||
379 | no_route: | |
380 | IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); | |
381 | kfree_skb(skb); | |
382 | return -EHOSTUNREACH; | |
383 | } | |
384 | ||
385 | ||
386 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
387 | { | |
388 | to->pkt_type = from->pkt_type; | |
389 | to->priority = from->priority; | |
390 | to->protocol = from->protocol; | |
391 | to->security = from->security; | |
392 | dst_release(to->dst); | |
393 | to->dst = dst_clone(from->dst); | |
394 | to->dev = from->dev; | |
395 | ||
396 | /* Copy the flags to each fragment. */ | |
397 | IPCB(to)->flags = IPCB(from)->flags; | |
398 | ||
399 | #ifdef CONFIG_NET_SCHED | |
400 | to->tc_index = from->tc_index; | |
401 | #endif | |
402 | #ifdef CONFIG_NETFILTER | |
403 | to->nfmark = from->nfmark; | |
404 | to->nfcache = from->nfcache; | |
405 | /* Connection association is same as pre-frag packet */ | |
406 | nf_conntrack_put(to->nfct); | |
407 | to->nfct = from->nfct; | |
408 | nf_conntrack_get(to->nfct); | |
409 | to->nfctinfo = from->nfctinfo; | |
410 | #ifdef CONFIG_BRIDGE_NETFILTER | |
411 | nf_bridge_put(to->nf_bridge); | |
412 | to->nf_bridge = from->nf_bridge; | |
413 | nf_bridge_get(to->nf_bridge); | |
414 | #endif | |
415 | #ifdef CONFIG_NETFILTER_DEBUG | |
416 | to->nf_debug = from->nf_debug; | |
417 | #endif | |
418 | #endif | |
419 | } | |
420 | ||
421 | /* | |
422 | * This IP datagram is too large to be sent in one piece. Break it up into | |
423 | * smaller pieces (each of size equal to IP header plus | |
424 | * a block of the data of the original IP data part) that will yet fit in a | |
425 | * single device frame, and queue such a frame for sending. | |
426 | */ | |
427 | ||
428 | int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) | |
429 | { | |
430 | struct iphdr *iph; | |
431 | int raw = 0; | |
432 | int ptr; | |
433 | struct net_device *dev; | |
434 | struct sk_buff *skb2; | |
435 | unsigned int mtu, hlen, left, len, ll_rs; | |
436 | int offset; | |
437 | int not_last_frag; | |
438 | struct rtable *rt = (struct rtable*)skb->dst; | |
439 | int err = 0; | |
440 | ||
441 | dev = rt->u.dst.dev; | |
442 | ||
443 | /* | |
444 | * Point into the IP datagram header. | |
445 | */ | |
446 | ||
447 | iph = skb->nh.iph; | |
448 | ||
449 | if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { | |
450 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, | |
451 | htonl(dst_mtu(&rt->u.dst))); | |
452 | kfree_skb(skb); | |
453 | return -EMSGSIZE; | |
454 | } | |
455 | ||
456 | /* | |
457 | * Setup starting values. | |
458 | */ | |
459 | ||
460 | hlen = iph->ihl * 4; | |
461 | mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ | |
462 | ||
463 | /* When frag_list is given, use it. First, check its validity: | |
464 | * some transformers could create wrong frag_list or break existing | |
465 | * one, it is not prohibited. In this case fall back to copying. | |
466 | * | |
467 | * LATER: this step can be merged to real generation of fragments, | |
468 | * we can switch to copy when see the first bad fragment. | |
469 | */ | |
470 | if (skb_shinfo(skb)->frag_list) { | |
471 | struct sk_buff *frag; | |
472 | int first_len = skb_pagelen(skb); | |
473 | ||
474 | if (first_len - hlen > mtu || | |
475 | ((first_len - hlen) & 7) || | |
476 | (iph->frag_off & htons(IP_MF|IP_OFFSET)) || | |
477 | skb_cloned(skb)) | |
478 | goto slow_path; | |
479 | ||
480 | for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { | |
481 | /* Correct geometry. */ | |
482 | if (frag->len > mtu || | |
483 | ((frag->len & 7) && frag->next) || | |
484 | skb_headroom(frag) < hlen) | |
485 | goto slow_path; | |
486 | ||
487 | /* Partially cloned skb? */ | |
488 | if (skb_shared(frag)) | |
489 | goto slow_path; | |
490 | } | |
491 | ||
492 | /* Everything is OK. Generate! */ | |
493 | ||
494 | err = 0; | |
495 | offset = 0; | |
496 | frag = skb_shinfo(skb)->frag_list; | |
497 | skb_shinfo(skb)->frag_list = NULL; | |
498 | skb->data_len = first_len - skb_headlen(skb); | |
499 | skb->len = first_len; | |
500 | iph->tot_len = htons(first_len); | |
501 | iph->frag_off = htons(IP_MF); | |
502 | ip_send_check(iph); | |
503 | ||
504 | for (;;) { | |
505 | /* Prepare header of the next frame, | |
506 | * before previous one went down. */ | |
507 | if (frag) { | |
508 | frag->ip_summed = CHECKSUM_NONE; | |
509 | frag->h.raw = frag->data; | |
510 | frag->nh.raw = __skb_push(frag, hlen); | |
511 | memcpy(frag->nh.raw, iph, hlen); | |
512 | iph = frag->nh.iph; | |
513 | iph->tot_len = htons(frag->len); | |
514 | ip_copy_metadata(frag, skb); | |
515 | if (offset == 0) | |
516 | ip_options_fragment(frag); | |
517 | offset += skb->len - hlen; | |
518 | iph->frag_off = htons(offset>>3); | |
519 | if (frag->next != NULL) | |
520 | iph->frag_off |= htons(IP_MF); | |
521 | /* Ready, complete checksum */ | |
522 | ip_send_check(iph); | |
523 | } | |
524 | ||
525 | err = output(skb); | |
526 | ||
527 | if (err || !frag) | |
528 | break; | |
529 | ||
530 | skb = frag; | |
531 | frag = skb->next; | |
532 | skb->next = NULL; | |
533 | } | |
534 | ||
535 | if (err == 0) { | |
536 | IP_INC_STATS(IPSTATS_MIB_FRAGOKS); | |
537 | return 0; | |
538 | } | |
539 | ||
540 | while (frag) { | |
541 | skb = frag->next; | |
542 | kfree_skb(frag); | |
543 | frag = skb; | |
544 | } | |
545 | IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); | |
546 | return err; | |
547 | } | |
548 | ||
549 | slow_path: | |
550 | left = skb->len - hlen; /* Space per frame */ | |
551 | ptr = raw + hlen; /* Where to start from */ | |
552 | ||
553 | #ifdef CONFIG_BRIDGE_NETFILTER | |
554 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, | |
555 | * we need to make room for the encapsulating header */ | |
556 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb)); | |
557 | mtu -= nf_bridge_pad(skb); | |
558 | #else | |
559 | ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev); | |
560 | #endif | |
561 | /* | |
562 | * Fragment the datagram. | |
563 | */ | |
564 | ||
565 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
566 | not_last_frag = iph->frag_off & htons(IP_MF); | |
567 | ||
568 | /* | |
569 | * Keep copying data until we run out. | |
570 | */ | |
571 | ||
572 | while(left > 0) { | |
573 | len = left; | |
574 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
575 | if (len > mtu) | |
576 | len = mtu; | |
577 | /* IF: we are not sending upto and including the packet end | |
578 | then align the next start on an eight byte boundary */ | |
579 | if (len < left) { | |
580 | len &= ~7; | |
581 | } | |
582 | /* | |
583 | * Allocate buffer. | |
584 | */ | |
585 | ||
586 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { | |
587 | NETDEBUG(printk(KERN_INFO "IP: frag: no memory for new fragment!\n")); | |
588 | err = -ENOMEM; | |
589 | goto fail; | |
590 | } | |
591 | ||
592 | /* | |
593 | * Set up data on packet | |
594 | */ | |
595 | ||
596 | ip_copy_metadata(skb2, skb); | |
597 | skb_reserve(skb2, ll_rs); | |
598 | skb_put(skb2, len + hlen); | |
599 | skb2->nh.raw = skb2->data; | |
600 | skb2->h.raw = skb2->data + hlen; | |
601 | ||
602 | /* | |
603 | * Charge the memory for the fragment to any owner | |
604 | * it might possess | |
605 | */ | |
606 | ||
607 | if (skb->sk) | |
608 | skb_set_owner_w(skb2, skb->sk); | |
609 | ||
610 | /* | |
611 | * Copy the packet header into the new buffer. | |
612 | */ | |
613 | ||
614 | memcpy(skb2->nh.raw, skb->data, hlen); | |
615 | ||
616 | /* | |
617 | * Copy a block of the IP datagram. | |
618 | */ | |
619 | if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) | |
620 | BUG(); | |
621 | left -= len; | |
622 | ||
623 | /* | |
624 | * Fill in the new header fields. | |
625 | */ | |
626 | iph = skb2->nh.iph; | |
627 | iph->frag_off = htons((offset >> 3)); | |
628 | ||
629 | /* ANK: dirty, but effective trick. Upgrade options only if | |
630 | * the segment to be fragmented was THE FIRST (otherwise, | |
631 | * options are already fixed) and make it ONCE | |
632 | * on the initial skb, so that all the following fragments | |
633 | * will inherit fixed options. | |
634 | */ | |
635 | if (offset == 0) | |
636 | ip_options_fragment(skb); | |
637 | ||
638 | /* | |
639 | * Added AC : If we are fragmenting a fragment that's not the | |
640 | * last fragment then keep MF on each bit | |
641 | */ | |
642 | if (left > 0 || not_last_frag) | |
643 | iph->frag_off |= htons(IP_MF); | |
644 | ptr += len; | |
645 | offset += len; | |
646 | ||
647 | /* | |
648 | * Put this fragment into the sending queue. | |
649 | */ | |
650 | ||
651 | IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); | |
652 | ||
653 | iph->tot_len = htons(len + hlen); | |
654 | ||
655 | ip_send_check(iph); | |
656 | ||
657 | err = output(skb2); | |
658 | if (err) | |
659 | goto fail; | |
660 | } | |
661 | kfree_skb(skb); | |
662 | IP_INC_STATS(IPSTATS_MIB_FRAGOKS); | |
663 | return err; | |
664 | ||
665 | fail: | |
666 | kfree_skb(skb); | |
667 | IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); | |
668 | return err; | |
669 | } | |
670 | ||
671 | int | |
672 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
673 | { | |
674 | struct iovec *iov = from; | |
675 | ||
676 | if (skb->ip_summed == CHECKSUM_HW) { | |
677 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) | |
678 | return -EFAULT; | |
679 | } else { | |
680 | unsigned int csum = 0; | |
681 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) | |
682 | return -EFAULT; | |
683 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
684 | } | |
685 | return 0; | |
686 | } | |
687 | ||
688 | static inline unsigned int | |
689 | csum_page(struct page *page, int offset, int copy) | |
690 | { | |
691 | char *kaddr; | |
692 | unsigned int csum; | |
693 | kaddr = kmap(page); | |
694 | csum = csum_partial(kaddr + offset, copy, 0); | |
695 | kunmap(page); | |
696 | return csum; | |
697 | } | |
698 | ||
699 | /* | |
700 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
701 | * from many pieces of data. Each pieces will be holded on the socket | |
702 | * until ip_push_pending_frames() is called. Each piece can be a page | |
703 | * or non-page data. | |
704 | * | |
705 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
706 | * this interface potentially. | |
707 | * | |
708 | * LATER: length must be adjusted by pad at tail, when it is required. | |
709 | */ | |
710 | int ip_append_data(struct sock *sk, | |
711 | int getfrag(void *from, char *to, int offset, int len, | |
712 | int odd, struct sk_buff *skb), | |
713 | void *from, int length, int transhdrlen, | |
714 | struct ipcm_cookie *ipc, struct rtable *rt, | |
715 | unsigned int flags) | |
716 | { | |
717 | struct inet_sock *inet = inet_sk(sk); | |
718 | struct sk_buff *skb; | |
719 | ||
720 | struct ip_options *opt = NULL; | |
721 | int hh_len; | |
722 | int exthdrlen; | |
723 | int mtu; | |
724 | int copy; | |
725 | int err; | |
726 | int offset = 0; | |
727 | unsigned int maxfraglen, fragheaderlen; | |
728 | int csummode = CHECKSUM_NONE; | |
729 | ||
730 | if (flags&MSG_PROBE) | |
731 | return 0; | |
732 | ||
733 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
734 | /* | |
735 | * setup for corking. | |
736 | */ | |
737 | opt = ipc->opt; | |
738 | if (opt) { | |
739 | if (inet->cork.opt == NULL) { | |
740 | inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); | |
741 | if (unlikely(inet->cork.opt == NULL)) | |
742 | return -ENOBUFS; | |
743 | } | |
744 | memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); | |
745 | inet->cork.flags |= IPCORK_OPT; | |
746 | inet->cork.addr = ipc->addr; | |
747 | } | |
748 | dst_hold(&rt->u.dst); | |
749 | inet->cork.fragsize = mtu = dst_mtu(rt->u.dst.path); | |
750 | inet->cork.rt = rt; | |
751 | inet->cork.length = 0; | |
752 | sk->sk_sndmsg_page = NULL; | |
753 | sk->sk_sndmsg_off = 0; | |
754 | if ((exthdrlen = rt->u.dst.header_len) != 0) { | |
755 | length += exthdrlen; | |
756 | transhdrlen += exthdrlen; | |
757 | } | |
758 | } else { | |
759 | rt = inet->cork.rt; | |
760 | if (inet->cork.flags & IPCORK_OPT) | |
761 | opt = inet->cork.opt; | |
762 | ||
763 | transhdrlen = 0; | |
764 | exthdrlen = 0; | |
765 | mtu = inet->cork.fragsize; | |
766 | } | |
767 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
768 | ||
769 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
770 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
771 | ||
772 | if (inet->cork.length + length > 0xFFFF - fragheaderlen) { | |
773 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen); | |
774 | return -EMSGSIZE; | |
775 | } | |
776 | ||
777 | /* | |
778 | * transhdrlen > 0 means that this is the first fragment and we wish | |
779 | * it won't be fragmented in the future. | |
780 | */ | |
781 | if (transhdrlen && | |
782 | length + fragheaderlen <= mtu && | |
783 | rt->u.dst.dev->features&(NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM) && | |
784 | !exthdrlen) | |
785 | csummode = CHECKSUM_HW; | |
786 | ||
787 | inet->cork.length += length; | |
788 | ||
789 | /* So, what's going on in the loop below? | |
790 | * | |
791 | * We use calculated fragment length to generate chained skb, | |
792 | * each of segments is IP fragment ready for sending to network after | |
793 | * adding appropriate IP header. | |
794 | */ | |
795 | ||
796 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
797 | goto alloc_new_skb; | |
798 | ||
799 | while (length > 0) { | |
800 | /* Check if the remaining data fits into current packet. */ | |
801 | copy = mtu - skb->len; | |
802 | if (copy < length) | |
803 | copy = maxfraglen - skb->len; | |
804 | if (copy <= 0) { | |
805 | char *data; | |
806 | unsigned int datalen; | |
807 | unsigned int fraglen; | |
808 | unsigned int fraggap; | |
809 | unsigned int alloclen; | |
810 | struct sk_buff *skb_prev; | |
811 | alloc_new_skb: | |
812 | skb_prev = skb; | |
813 | if (skb_prev) | |
814 | fraggap = skb_prev->len - maxfraglen; | |
815 | else | |
816 | fraggap = 0; | |
817 | ||
818 | /* | |
819 | * If remaining data exceeds the mtu, | |
820 | * we know we need more fragment(s). | |
821 | */ | |
822 | datalen = length + fraggap; | |
823 | if (datalen > mtu - fragheaderlen) | |
824 | datalen = maxfraglen - fragheaderlen; | |
825 | fraglen = datalen + fragheaderlen; | |
826 | ||
827 | if ((flags & MSG_MORE) && | |
828 | !(rt->u.dst.dev->features&NETIF_F_SG)) | |
829 | alloclen = mtu; | |
830 | else | |
831 | alloclen = datalen + fragheaderlen; | |
832 | ||
833 | /* The last fragment gets additional space at tail. | |
834 | * Note, with MSG_MORE we overallocate on fragments, | |
835 | * because we have no idea what fragment will be | |
836 | * the last. | |
837 | */ | |
838 | if (datalen == length) | |
839 | alloclen += rt->u.dst.trailer_len; | |
840 | ||
841 | if (transhdrlen) { | |
842 | skb = sock_alloc_send_skb(sk, | |
843 | alloclen + hh_len + 15, | |
844 | (flags & MSG_DONTWAIT), &err); | |
845 | } else { | |
846 | skb = NULL; | |
847 | if (atomic_read(&sk->sk_wmem_alloc) <= | |
848 | 2 * sk->sk_sndbuf) | |
849 | skb = sock_wmalloc(sk, | |
850 | alloclen + hh_len + 15, 1, | |
851 | sk->sk_allocation); | |
852 | if (unlikely(skb == NULL)) | |
853 | err = -ENOBUFS; | |
854 | } | |
855 | if (skb == NULL) | |
856 | goto error; | |
857 | ||
858 | /* | |
859 | * Fill in the control structures | |
860 | */ | |
861 | skb->ip_summed = csummode; | |
862 | skb->csum = 0; | |
863 | skb_reserve(skb, hh_len); | |
864 | ||
865 | /* | |
866 | * Find where to start putting bytes. | |
867 | */ | |
868 | data = skb_put(skb, fraglen); | |
869 | skb->nh.raw = data + exthdrlen; | |
870 | data += fragheaderlen; | |
871 | skb->h.raw = data + exthdrlen; | |
872 | ||
873 | if (fraggap) { | |
874 | skb->csum = skb_copy_and_csum_bits( | |
875 | skb_prev, maxfraglen, | |
876 | data + transhdrlen, fraggap, 0); | |
877 | skb_prev->csum = csum_sub(skb_prev->csum, | |
878 | skb->csum); | |
879 | data += fraggap; | |
880 | skb_trim(skb_prev, maxfraglen); | |
881 | } | |
882 | ||
883 | copy = datalen - transhdrlen - fraggap; | |
884 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
885 | err = -EFAULT; | |
886 | kfree_skb(skb); | |
887 | goto error; | |
888 | } | |
889 | ||
890 | offset += copy; | |
891 | length -= datalen - fraggap; | |
892 | transhdrlen = 0; | |
893 | exthdrlen = 0; | |
894 | csummode = CHECKSUM_NONE; | |
895 | ||
896 | /* | |
897 | * Put the packet on the pending queue. | |
898 | */ | |
899 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
900 | continue; | |
901 | } | |
902 | ||
903 | if (copy > length) | |
904 | copy = length; | |
905 | ||
906 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) { | |
907 | unsigned int off; | |
908 | ||
909 | off = skb->len; | |
910 | if (getfrag(from, skb_put(skb, copy), | |
911 | offset, copy, off, skb) < 0) { | |
912 | __skb_trim(skb, off); | |
913 | err = -EFAULT; | |
914 | goto error; | |
915 | } | |
916 | } else { | |
917 | int i = skb_shinfo(skb)->nr_frags; | |
918 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; | |
919 | struct page *page = sk->sk_sndmsg_page; | |
920 | int off = sk->sk_sndmsg_off; | |
921 | unsigned int left; | |
922 | ||
923 | if (page && (left = PAGE_SIZE - off) > 0) { | |
924 | if (copy >= left) | |
925 | copy = left; | |
926 | if (page != frag->page) { | |
927 | if (i == MAX_SKB_FRAGS) { | |
928 | err = -EMSGSIZE; | |
929 | goto error; | |
930 | } | |
931 | get_page(page); | |
932 | skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); | |
933 | frag = &skb_shinfo(skb)->frags[i]; | |
934 | } | |
935 | } else if (i < MAX_SKB_FRAGS) { | |
936 | if (copy > PAGE_SIZE) | |
937 | copy = PAGE_SIZE; | |
938 | page = alloc_pages(sk->sk_allocation, 0); | |
939 | if (page == NULL) { | |
940 | err = -ENOMEM; | |
941 | goto error; | |
942 | } | |
943 | sk->sk_sndmsg_page = page; | |
944 | sk->sk_sndmsg_off = 0; | |
945 | ||
946 | skb_fill_page_desc(skb, i, page, 0, 0); | |
947 | frag = &skb_shinfo(skb)->frags[i]; | |
948 | skb->truesize += PAGE_SIZE; | |
949 | atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); | |
950 | } else { | |
951 | err = -EMSGSIZE; | |
952 | goto error; | |
953 | } | |
954 | if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { | |
955 | err = -EFAULT; | |
956 | goto error; | |
957 | } | |
958 | sk->sk_sndmsg_off += copy; | |
959 | frag->size += copy; | |
960 | skb->len += copy; | |
961 | skb->data_len += copy; | |
962 | } | |
963 | offset += copy; | |
964 | length -= copy; | |
965 | } | |
966 | ||
967 | return 0; | |
968 | ||
969 | error: | |
970 | inet->cork.length -= length; | |
971 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
972 | return err; | |
973 | } | |
974 | ||
975 | ssize_t ip_append_page(struct sock *sk, struct page *page, | |
976 | int offset, size_t size, int flags) | |
977 | { | |
978 | struct inet_sock *inet = inet_sk(sk); | |
979 | struct sk_buff *skb; | |
980 | struct rtable *rt; | |
981 | struct ip_options *opt = NULL; | |
982 | int hh_len; | |
983 | int mtu; | |
984 | int len; | |
985 | int err; | |
986 | unsigned int maxfraglen, fragheaderlen, fraggap; | |
987 | ||
988 | if (inet->hdrincl) | |
989 | return -EPERM; | |
990 | ||
991 | if (flags&MSG_PROBE) | |
992 | return 0; | |
993 | ||
994 | if (skb_queue_empty(&sk->sk_write_queue)) | |
995 | return -EINVAL; | |
996 | ||
997 | rt = inet->cork.rt; | |
998 | if (inet->cork.flags & IPCORK_OPT) | |
999 | opt = inet->cork.opt; | |
1000 | ||
1001 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) | |
1002 | return -EOPNOTSUPP; | |
1003 | ||
1004 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
1005 | mtu = inet->cork.fragsize; | |
1006 | ||
1007 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1008 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1009 | ||
1010 | if (inet->cork.length + size > 0xFFFF - fragheaderlen) { | |
1011 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); | |
1012 | return -EMSGSIZE; | |
1013 | } | |
1014 | ||
1015 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
1016 | return -EINVAL; | |
1017 | ||
1018 | inet->cork.length += size; | |
1019 | ||
1020 | while (size > 0) { | |
1021 | int i; | |
1022 | ||
1023 | /* Check if the remaining data fits into current packet. */ | |
1024 | len = mtu - skb->len; | |
1025 | if (len < size) | |
1026 | len = maxfraglen - skb->len; | |
1027 | if (len <= 0) { | |
1028 | struct sk_buff *skb_prev; | |
1029 | char *data; | |
1030 | struct iphdr *iph; | |
1031 | int alloclen; | |
1032 | ||
1033 | skb_prev = skb; | |
1034 | if (skb_prev) | |
1035 | fraggap = skb_prev->len - maxfraglen; | |
1036 | else | |
1037 | fraggap = 0; | |
1038 | ||
1039 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1040 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1041 | if (unlikely(!skb)) { | |
1042 | err = -ENOBUFS; | |
1043 | goto error; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * Fill in the control structures | |
1048 | */ | |
1049 | skb->ip_summed = CHECKSUM_NONE; | |
1050 | skb->csum = 0; | |
1051 | skb_reserve(skb, hh_len); | |
1052 | ||
1053 | /* | |
1054 | * Find where to start putting bytes. | |
1055 | */ | |
1056 | data = skb_put(skb, fragheaderlen + fraggap); | |
1057 | skb->nh.iph = iph = (struct iphdr *)data; | |
1058 | data += fragheaderlen; | |
1059 | skb->h.raw = data; | |
1060 | ||
1061 | if (fraggap) { | |
1062 | skb->csum = skb_copy_and_csum_bits( | |
1063 | skb_prev, maxfraglen, | |
1064 | data, fraggap, 0); | |
1065 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1066 | skb->csum); | |
1067 | skb_trim(skb_prev, maxfraglen); | |
1068 | } | |
1069 | ||
1070 | /* | |
1071 | * Put the packet on the pending queue. | |
1072 | */ | |
1073 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1074 | continue; | |
1075 | } | |
1076 | ||
1077 | i = skb_shinfo(skb)->nr_frags; | |
1078 | if (len > size) | |
1079 | len = size; | |
1080 | if (skb_can_coalesce(skb, i, page, offset)) { | |
1081 | skb_shinfo(skb)->frags[i-1].size += len; | |
1082 | } else if (i < MAX_SKB_FRAGS) { | |
1083 | get_page(page); | |
1084 | skb_fill_page_desc(skb, i, page, offset, len); | |
1085 | } else { | |
1086 | err = -EMSGSIZE; | |
1087 | goto error; | |
1088 | } | |
1089 | ||
1090 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1091 | unsigned int csum; | |
1092 | csum = csum_page(page, offset, len); | |
1093 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1094 | } | |
1095 | ||
1096 | skb->len += len; | |
1097 | skb->data_len += len; | |
1098 | offset += len; | |
1099 | size -= len; | |
1100 | } | |
1101 | return 0; | |
1102 | ||
1103 | error: | |
1104 | inet->cork.length -= size; | |
1105 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
1106 | return err; | |
1107 | } | |
1108 | ||
1109 | /* | |
1110 | * Combined all pending IP fragments on the socket as one IP datagram | |
1111 | * and push them out. | |
1112 | */ | |
1113 | int ip_push_pending_frames(struct sock *sk) | |
1114 | { | |
1115 | struct sk_buff *skb, *tmp_skb; | |
1116 | struct sk_buff **tail_skb; | |
1117 | struct inet_sock *inet = inet_sk(sk); | |
1118 | struct ip_options *opt = NULL; | |
1119 | struct rtable *rt = inet->cork.rt; | |
1120 | struct iphdr *iph; | |
1121 | int df = 0; | |
1122 | __u8 ttl; | |
1123 | int err = 0; | |
1124 | ||
1125 | if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) | |
1126 | goto out; | |
1127 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1128 | ||
1129 | /* move skb->data to ip header from ext header */ | |
1130 | if (skb->data < skb->nh.raw) | |
1131 | __skb_pull(skb, skb->nh.raw - skb->data); | |
1132 | while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { | |
1133 | __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); | |
1134 | *tail_skb = tmp_skb; | |
1135 | tail_skb = &(tmp_skb->next); | |
1136 | skb->len += tmp_skb->len; | |
1137 | skb->data_len += tmp_skb->len; | |
1138 | skb->truesize += tmp_skb->truesize; | |
1139 | __sock_put(tmp_skb->sk); | |
1140 | tmp_skb->destructor = NULL; | |
1141 | tmp_skb->sk = NULL; | |
1142 | } | |
1143 | ||
1144 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1145 | * to fragment the frame generated here. No matter, what transforms | |
1146 | * how transforms change size of the packet, it will come out. | |
1147 | */ | |
1148 | if (inet->pmtudisc != IP_PMTUDISC_DO) | |
1149 | skb->local_df = 1; | |
1150 | ||
1151 | /* DF bit is set when we want to see DF on outgoing frames. | |
1152 | * If local_df is set too, we still allow to fragment this frame | |
1153 | * locally. */ | |
1154 | if (inet->pmtudisc == IP_PMTUDISC_DO || | |
1155 | (skb->len <= dst_mtu(&rt->u.dst) && | |
1156 | ip_dont_fragment(sk, &rt->u.dst))) | |
1157 | df = htons(IP_DF); | |
1158 | ||
1159 | if (inet->cork.flags & IPCORK_OPT) | |
1160 | opt = inet->cork.opt; | |
1161 | ||
1162 | if (rt->rt_type == RTN_MULTICAST) | |
1163 | ttl = inet->mc_ttl; | |
1164 | else | |
1165 | ttl = ip_select_ttl(inet, &rt->u.dst); | |
1166 | ||
1167 | iph = (struct iphdr *)skb->data; | |
1168 | iph->version = 4; | |
1169 | iph->ihl = 5; | |
1170 | if (opt) { | |
1171 | iph->ihl += opt->optlen>>2; | |
1172 | ip_options_build(skb, opt, inet->cork.addr, rt, 0); | |
1173 | } | |
1174 | iph->tos = inet->tos; | |
1175 | iph->tot_len = htons(skb->len); | |
1176 | iph->frag_off = df; | |
1177 | if (!df) { | |
1178 | __ip_select_ident(iph, &rt->u.dst, 0); | |
1179 | } else { | |
1180 | iph->id = htons(inet->id++); | |
1181 | } | |
1182 | iph->ttl = ttl; | |
1183 | iph->protocol = sk->sk_protocol; | |
1184 | iph->saddr = rt->rt_src; | |
1185 | iph->daddr = rt->rt_dst; | |
1186 | ip_send_check(iph); | |
1187 | ||
1188 | skb->priority = sk->sk_priority; | |
1189 | skb->dst = dst_clone(&rt->u.dst); | |
1190 | ||
1191 | /* Netfilter gets whole the not fragmented skb. */ | |
1192 | err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, | |
1193 | skb->dst->dev, dst_output); | |
1194 | if (err) { | |
1195 | if (err > 0) | |
1196 | err = inet->recverr ? net_xmit_errno(err) : 0; | |
1197 | if (err) | |
1198 | goto error; | |
1199 | } | |
1200 | ||
1201 | out: | |
1202 | inet->cork.flags &= ~IPCORK_OPT; | |
1203 | if (inet->cork.opt) { | |
1204 | kfree(inet->cork.opt); | |
1205 | inet->cork.opt = NULL; | |
1206 | } | |
1207 | if (inet->cork.rt) { | |
1208 | ip_rt_put(inet->cork.rt); | |
1209 | inet->cork.rt = NULL; | |
1210 | } | |
1211 | return err; | |
1212 | ||
1213 | error: | |
1214 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
1215 | goto out; | |
1216 | } | |
1217 | ||
1218 | /* | |
1219 | * Throw away all pending data on the socket. | |
1220 | */ | |
1221 | void ip_flush_pending_frames(struct sock *sk) | |
1222 | { | |
1223 | struct inet_sock *inet = inet_sk(sk); | |
1224 | struct sk_buff *skb; | |
1225 | ||
1226 | while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) | |
1227 | kfree_skb(skb); | |
1228 | ||
1229 | inet->cork.flags &= ~IPCORK_OPT; | |
1230 | if (inet->cork.opt) { | |
1231 | kfree(inet->cork.opt); | |
1232 | inet->cork.opt = NULL; | |
1233 | } | |
1234 | if (inet->cork.rt) { | |
1235 | ip_rt_put(inet->cork.rt); | |
1236 | inet->cork.rt = NULL; | |
1237 | } | |
1238 | } | |
1239 | ||
1240 | ||
1241 | /* | |
1242 | * Fetch data from kernel space and fill in checksum if needed. | |
1243 | */ | |
1244 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, | |
1245 | int len, int odd, struct sk_buff *skb) | |
1246 | { | |
1247 | unsigned int csum; | |
1248 | ||
1249 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); | |
1250 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
1251 | return 0; | |
1252 | } | |
1253 | ||
1254 | /* | |
1255 | * Generic function to send a packet as reply to another packet. | |
1256 | * Used to send TCP resets so far. ICMP should use this function too. | |
1257 | * | |
1258 | * Should run single threaded per socket because it uses the sock | |
1259 | * structure to pass arguments. | |
1260 | * | |
1261 | * LATER: switch from ip_build_xmit to ip_append_* | |
1262 | */ | |
1263 | void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, | |
1264 | unsigned int len) | |
1265 | { | |
1266 | struct inet_sock *inet = inet_sk(sk); | |
1267 | struct { | |
1268 | struct ip_options opt; | |
1269 | char data[40]; | |
1270 | } replyopts; | |
1271 | struct ipcm_cookie ipc; | |
1272 | u32 daddr; | |
1273 | struct rtable *rt = (struct rtable*)skb->dst; | |
1274 | ||
1275 | if (ip_options_echo(&replyopts.opt, skb)) | |
1276 | return; | |
1277 | ||
1278 | daddr = ipc.addr = rt->rt_src; | |
1279 | ipc.opt = NULL; | |
1280 | ||
1281 | if (replyopts.opt.optlen) { | |
1282 | ipc.opt = &replyopts.opt; | |
1283 | ||
1284 | if (ipc.opt->srr) | |
1285 | daddr = replyopts.opt.faddr; | |
1286 | } | |
1287 | ||
1288 | { | |
1289 | struct flowi fl = { .nl_u = { .ip4_u = | |
1290 | { .daddr = daddr, | |
1291 | .saddr = rt->rt_spec_dst, | |
1292 | .tos = RT_TOS(skb->nh.iph->tos) } }, | |
1293 | /* Not quite clean, but right. */ | |
1294 | .uli_u = { .ports = | |
1295 | { .sport = skb->h.th->dest, | |
1296 | .dport = skb->h.th->source } }, | |
1297 | .proto = sk->sk_protocol }; | |
1298 | if (ip_route_output_key(&rt, &fl)) | |
1299 | return; | |
1300 | } | |
1301 | ||
1302 | /* And let IP do all the hard work. | |
1303 | ||
1304 | This chunk is not reenterable, hence spinlock. | |
1305 | Note that it uses the fact, that this function is called | |
1306 | with locally disabled BH and that sk cannot be already spinlocked. | |
1307 | */ | |
1308 | bh_lock_sock(sk); | |
1309 | inet->tos = skb->nh.iph->tos; | |
1310 | sk->sk_priority = skb->priority; | |
1311 | sk->sk_protocol = skb->nh.iph->protocol; | |
1312 | ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, | |
1313 | &ipc, rt, MSG_DONTWAIT); | |
1314 | if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { | |
1315 | if (arg->csumoffset >= 0) | |
1316 | *((u16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum)); | |
1317 | skb->ip_summed = CHECKSUM_NONE; | |
1318 | ip_push_pending_frames(sk); | |
1319 | } | |
1320 | ||
1321 | bh_unlock_sock(sk); | |
1322 | ||
1323 | ip_rt_put(rt); | |
1324 | } | |
1325 | ||
1326 | /* | |
1327 | * IP protocol layer initialiser | |
1328 | */ | |
1329 | ||
1330 | static struct packet_type ip_packet_type = { | |
1331 | .type = __constant_htons(ETH_P_IP), | |
1332 | .func = ip_rcv, | |
1333 | }; | |
1334 | ||
1335 | /* | |
1336 | * IP registers the packet type and then calls the subprotocol initialisers | |
1337 | */ | |
1338 | ||
1339 | void __init ip_init(void) | |
1340 | { | |
1341 | dev_add_pack(&ip_packet_type); | |
1342 | ||
1343 | ip_rt_init(); | |
1344 | inet_initpeers(); | |
1345 | ||
1346 | #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) | |
1347 | igmp_mc_proc_init(); | |
1348 | #endif | |
1349 | } | |
1350 | ||
1351 | EXPORT_SYMBOL(ip_finish_output); | |
1352 | EXPORT_SYMBOL(ip_fragment); | |
1353 | EXPORT_SYMBOL(ip_generic_getfrag); | |
1354 | EXPORT_SYMBOL(ip_queue_xmit); | |
1355 | EXPORT_SYMBOL(ip_send_check); | |
1356 | ||
1357 | #ifdef CONFIG_SYSCTL | |
1358 | EXPORT_SYMBOL(sysctl_ip_default_ttl); | |
1359 | #endif |