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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 | * | |
02c30a84 | 10 | * Authors: Ross Biro |
1da177e4 LT |
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> | |
cfacb057 | 72 | #include <net/xfrm.h> |
1da177e4 LT |
73 | #include <linux/skbuff.h> |
74 | #include <net/sock.h> | |
75 | #include <net/arp.h> | |
76 | #include <net/icmp.h> | |
1da177e4 LT |
77 | #include <net/checksum.h> |
78 | #include <net/inetpeer.h> | |
79 | #include <net/checksum.h> | |
80 | #include <linux/igmp.h> | |
81 | #include <linux/netfilter_ipv4.h> | |
82 | #include <linux/netfilter_bridge.h> | |
83 | #include <linux/mroute.h> | |
84 | #include <linux/netlink.h> | |
6cbb0df7 | 85 | #include <linux/tcp.h> |
1da177e4 | 86 | |
1da177e4 LT |
87 | int sysctl_ip_default_ttl = IPDEFTTL; |
88 | ||
89 | /* Generate a checksum for an outgoing IP datagram. */ | |
90 | __inline__ void ip_send_check(struct iphdr *iph) | |
91 | { | |
92 | iph->check = 0; | |
93 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
94 | } | |
95 | ||
96 | /* dev_loopback_xmit for use with netfilter. */ | |
97 | static int ip_dev_loopback_xmit(struct sk_buff *newskb) | |
98 | { | |
99 | newskb->mac.raw = newskb->data; | |
100 | __skb_pull(newskb, newskb->nh.raw - newskb->data); | |
101 | newskb->pkt_type = PACKET_LOOPBACK; | |
102 | newskb->ip_summed = CHECKSUM_UNNECESSARY; | |
103 | BUG_TRAP(newskb->dst); | |
1da177e4 LT |
104 | netif_rx(newskb); |
105 | return 0; | |
106 | } | |
107 | ||
108 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) | |
109 | { | |
110 | int ttl = inet->uc_ttl; | |
111 | ||
112 | if (ttl < 0) | |
113 | ttl = dst_metric(dst, RTAX_HOPLIMIT); | |
114 | return ttl; | |
115 | } | |
116 | ||
117 | /* | |
118 | * Add an ip header to a skbuff and send it out. | |
119 | * | |
120 | */ | |
121 | int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, | |
122 | u32 saddr, u32 daddr, struct ip_options *opt) | |
123 | { | |
124 | struct inet_sock *inet = inet_sk(sk); | |
125 | struct rtable *rt = (struct rtable *)skb->dst; | |
126 | struct iphdr *iph; | |
127 | ||
128 | /* Build the IP header. */ | |
129 | if (opt) | |
130 | iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); | |
131 | else | |
132 | iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); | |
133 | ||
134 | iph->version = 4; | |
135 | iph->ihl = 5; | |
136 | iph->tos = inet->tos; | |
137 | if (ip_dont_fragment(sk, &rt->u.dst)) | |
138 | iph->frag_off = htons(IP_DF); | |
139 | else | |
140 | iph->frag_off = 0; | |
141 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
142 | iph->daddr = rt->rt_dst; | |
143 | iph->saddr = rt->rt_src; | |
144 | iph->protocol = sk->sk_protocol; | |
145 | iph->tot_len = htons(skb->len); | |
146 | ip_select_ident(iph, &rt->u.dst, sk); | |
147 | skb->nh.iph = iph; | |
148 | ||
149 | if (opt && opt->optlen) { | |
150 | iph->ihl += opt->optlen>>2; | |
151 | ip_options_build(skb, opt, daddr, rt, 0); | |
152 | } | |
153 | ip_send_check(iph); | |
154 | ||
155 | skb->priority = sk->sk_priority; | |
156 | ||
157 | /* Send it out. */ | |
158 | return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, | |
159 | dst_output); | |
160 | } | |
161 | ||
d8c97a94 ACM |
162 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); |
163 | ||
1da177e4 LT |
164 | static inline int ip_finish_output2(struct sk_buff *skb) |
165 | { | |
166 | struct dst_entry *dst = skb->dst; | |
167 | struct hh_cache *hh = dst->hh; | |
168 | struct net_device *dev = dst->dev; | |
169 | int hh_len = LL_RESERVED_SPACE(dev); | |
170 | ||
171 | /* Be paranoid, rather than too clever. */ | |
172 | if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) { | |
173 | struct sk_buff *skb2; | |
174 | ||
175 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
176 | if (skb2 == NULL) { | |
177 | kfree_skb(skb); | |
178 | return -ENOMEM; | |
179 | } | |
180 | if (skb->sk) | |
181 | skb_set_owner_w(skb2, skb->sk); | |
182 | kfree_skb(skb); | |
183 | skb = skb2; | |
184 | } | |
185 | ||
1da177e4 LT |
186 | if (hh) { |
187 | int hh_alen; | |
188 | ||
189 | read_lock_bh(&hh->hh_lock); | |
190 | hh_alen = HH_DATA_ALIGN(hh->hh_len); | |
191 | memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); | |
192 | read_unlock_bh(&hh->hh_lock); | |
193 | skb_push(skb, hh->hh_len); | |
194 | return hh->hh_output(skb); | |
195 | } else if (dst->neighbour) | |
196 | return dst->neighbour->output(skb); | |
197 | ||
198 | if (net_ratelimit()) | |
199 | printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); | |
200 | kfree_skb(skb); | |
201 | return -EINVAL; | |
202 | } | |
203 | ||
33d043d6 | 204 | static inline int ip_finish_output(struct sk_buff *skb) |
1da177e4 | 205 | { |
5c901daa PM |
206 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) |
207 | /* Policy lookup after SNAT yielded a new policy */ | |
48d5cad8 PM |
208 | if (skb->dst->xfrm != NULL) { |
209 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
210 | return dst_output(skb); | |
211 | } | |
5c901daa | 212 | #endif |
1bd9bef6 PM |
213 | if (skb->len > dst_mtu(skb->dst) && |
214 | !(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size)) | |
215 | return ip_fragment(skb, ip_finish_output2); | |
216 | else | |
217 | return ip_finish_output2(skb); | |
1da177e4 LT |
218 | } |
219 | ||
220 | int ip_mc_output(struct sk_buff *skb) | |
221 | { | |
222 | struct sock *sk = skb->sk; | |
223 | struct rtable *rt = (struct rtable*)skb->dst; | |
224 | struct net_device *dev = rt->u.dst.dev; | |
225 | ||
226 | /* | |
227 | * If the indicated interface is up and running, send the packet. | |
228 | */ | |
229 | IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); | |
230 | ||
231 | skb->dev = dev; | |
232 | skb->protocol = htons(ETH_P_IP); | |
233 | ||
234 | /* | |
235 | * Multicasts are looped back for other local users | |
236 | */ | |
237 | ||
238 | if (rt->rt_flags&RTCF_MULTICAST) { | |
239 | if ((!sk || inet_sk(sk)->mc_loop) | |
240 | #ifdef CONFIG_IP_MROUTE | |
241 | /* Small optimization: do not loopback not local frames, | |
242 | which returned after forwarding; they will be dropped | |
243 | by ip_mr_input in any case. | |
244 | Note, that local frames are looped back to be delivered | |
245 | to local recipients. | |
246 | ||
247 | This check is duplicated in ip_mr_input at the moment. | |
248 | */ | |
249 | && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) | |
250 | #endif | |
251 | ) { | |
252 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
253 | if (newskb) | |
254 | NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, | |
255 | newskb->dev, | |
256 | ip_dev_loopback_xmit); | |
257 | } | |
258 | ||
259 | /* Multicasts with ttl 0 must not go beyond the host */ | |
260 | ||
261 | if (skb->nh.iph->ttl == 0) { | |
262 | kfree_skb(skb); | |
263 | return 0; | |
264 | } | |
265 | } | |
266 | ||
267 | if (rt->rt_flags&RTCF_BROADCAST) { | |
268 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
269 | if (newskb) | |
270 | NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, | |
271 | newskb->dev, ip_dev_loopback_xmit); | |
272 | } | |
273 | ||
48d5cad8 PM |
274 | return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev, |
275 | ip_finish_output, | |
276 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
1da177e4 LT |
277 | } |
278 | ||
279 | int ip_output(struct sk_buff *skb) | |
280 | { | |
1bd9bef6 PM |
281 | struct net_device *dev = skb->dst->dev; |
282 | ||
1da177e4 LT |
283 | IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS); |
284 | ||
1bd9bef6 PM |
285 | skb->dev = dev; |
286 | skb->protocol = htons(ETH_P_IP); | |
287 | ||
48d5cad8 PM |
288 | return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, |
289 | ip_finish_output, | |
290 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
1da177e4 LT |
291 | } |
292 | ||
293 | int ip_queue_xmit(struct sk_buff *skb, int ipfragok) | |
294 | { | |
295 | struct sock *sk = skb->sk; | |
296 | struct inet_sock *inet = inet_sk(sk); | |
297 | struct ip_options *opt = inet->opt; | |
298 | struct rtable *rt; | |
299 | struct iphdr *iph; | |
300 | ||
301 | /* Skip all of this if the packet is already routed, | |
302 | * f.e. by something like SCTP. | |
303 | */ | |
304 | rt = (struct rtable *) skb->dst; | |
305 | if (rt != NULL) | |
306 | goto packet_routed; | |
307 | ||
308 | /* Make sure we can route this packet. */ | |
309 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
310 | if (rt == NULL) { | |
311 | u32 daddr; | |
312 | ||
313 | /* Use correct destination address if we have options. */ | |
314 | daddr = inet->daddr; | |
315 | if(opt && opt->srr) | |
316 | daddr = opt->faddr; | |
317 | ||
318 | { | |
319 | struct flowi fl = { .oif = sk->sk_bound_dev_if, | |
320 | .nl_u = { .ip4_u = | |
321 | { .daddr = daddr, | |
322 | .saddr = inet->saddr, | |
323 | .tos = RT_CONN_FLAGS(sk) } }, | |
324 | .proto = sk->sk_protocol, | |
325 | .uli_u = { .ports = | |
326 | { .sport = inet->sport, | |
327 | .dport = inet->dport } } }; | |
328 | ||
329 | /* If this fails, retransmit mechanism of transport layer will | |
330 | * keep trying until route appears or the connection times | |
331 | * itself out. | |
332 | */ | |
333 | if (ip_route_output_flow(&rt, &fl, sk, 0)) | |
334 | goto no_route; | |
335 | } | |
6cbb0df7 | 336 | sk_setup_caps(sk, &rt->u.dst); |
1da177e4 LT |
337 | } |
338 | skb->dst = dst_clone(&rt->u.dst); | |
339 | ||
340 | packet_routed: | |
341 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) | |
342 | goto no_route; | |
343 | ||
344 | /* OK, we know where to send it, allocate and build IP header. */ | |
345 | iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
346 | *((__u16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); | |
347 | iph->tot_len = htons(skb->len); | |
348 | if (ip_dont_fragment(sk, &rt->u.dst) && !ipfragok) | |
349 | iph->frag_off = htons(IP_DF); | |
350 | else | |
351 | iph->frag_off = 0; | |
352 | iph->ttl = ip_select_ttl(inet, &rt->u.dst); | |
353 | iph->protocol = sk->sk_protocol; | |
354 | iph->saddr = rt->rt_src; | |
355 | iph->daddr = rt->rt_dst; | |
356 | skb->nh.iph = iph; | |
357 | /* Transport layer set skb->h.foo itself. */ | |
358 | ||
359 | if (opt && opt->optlen) { | |
360 | iph->ihl += opt->optlen >> 2; | |
361 | ip_options_build(skb, opt, inet->daddr, rt, 0); | |
362 | } | |
363 | ||
89f5f0ae HX |
364 | ip_select_ident_more(iph, &rt->u.dst, sk, |
365 | (skb_shinfo(skb)->tso_segs ?: 1) - 1); | |
1da177e4 LT |
366 | |
367 | /* Add an IP checksum. */ | |
368 | ip_send_check(iph); | |
369 | ||
370 | skb->priority = sk->sk_priority; | |
371 | ||
372 | return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, | |
373 | dst_output); | |
374 | ||
375 | no_route: | |
376 | IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES); | |
377 | kfree_skb(skb); | |
378 | return -EHOSTUNREACH; | |
379 | } | |
380 | ||
381 | ||
382 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
383 | { | |
384 | to->pkt_type = from->pkt_type; | |
385 | to->priority = from->priority; | |
386 | to->protocol = from->protocol; | |
1da177e4 LT |
387 | dst_release(to->dst); |
388 | to->dst = dst_clone(from->dst); | |
389 | to->dev = from->dev; | |
390 | ||
391 | /* Copy the flags to each fragment. */ | |
392 | IPCB(to)->flags = IPCB(from)->flags; | |
393 | ||
394 | #ifdef CONFIG_NET_SCHED | |
395 | to->tc_index = from->tc_index; | |
396 | #endif | |
397 | #ifdef CONFIG_NETFILTER | |
398 | to->nfmark = from->nfmark; | |
1da177e4 LT |
399 | /* Connection association is same as pre-frag packet */ |
400 | nf_conntrack_put(to->nfct); | |
401 | to->nfct = from->nfct; | |
402 | nf_conntrack_get(to->nfct); | |
403 | to->nfctinfo = from->nfctinfo; | |
c98d80ed JA |
404 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
405 | to->ipvs_property = from->ipvs_property; | |
406 | #endif | |
1da177e4 LT |
407 | #ifdef CONFIG_BRIDGE_NETFILTER |
408 | nf_bridge_put(to->nf_bridge); | |
409 | to->nf_bridge = from->nf_bridge; | |
410 | nf_bridge_get(to->nf_bridge); | |
411 | #endif | |
1da177e4 | 412 | #endif |
984bc16c | 413 | skb_copy_secmark(to, from); |
1da177e4 LT |
414 | } |
415 | ||
416 | /* | |
417 | * This IP datagram is too large to be sent in one piece. Break it up into | |
418 | * smaller pieces (each of size equal to IP header plus | |
419 | * a block of the data of the original IP data part) that will yet fit in a | |
420 | * single device frame, and queue such a frame for sending. | |
421 | */ | |
422 | ||
2e2f7aef | 423 | int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) |
1da177e4 LT |
424 | { |
425 | struct iphdr *iph; | |
426 | int raw = 0; | |
427 | int ptr; | |
428 | struct net_device *dev; | |
429 | struct sk_buff *skb2; | |
430 | unsigned int mtu, hlen, left, len, ll_rs; | |
431 | int offset; | |
76ab608d | 432 | __be16 not_last_frag; |
1da177e4 LT |
433 | struct rtable *rt = (struct rtable*)skb->dst; |
434 | int err = 0; | |
435 | ||
436 | dev = rt->u.dst.dev; | |
437 | ||
438 | /* | |
439 | * Point into the IP datagram header. | |
440 | */ | |
441 | ||
442 | iph = skb->nh.iph; | |
443 | ||
444 | if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { | |
445 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, | |
446 | htonl(dst_mtu(&rt->u.dst))); | |
447 | kfree_skb(skb); | |
448 | return -EMSGSIZE; | |
449 | } | |
450 | ||
451 | /* | |
452 | * Setup starting values. | |
453 | */ | |
454 | ||
455 | hlen = iph->ihl * 4; | |
456 | mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ | |
89cee8b1 | 457 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; |
1da177e4 LT |
458 | |
459 | /* When frag_list is given, use it. First, check its validity: | |
460 | * some transformers could create wrong frag_list or break existing | |
461 | * one, it is not prohibited. In this case fall back to copying. | |
462 | * | |
463 | * LATER: this step can be merged to real generation of fragments, | |
464 | * we can switch to copy when see the first bad fragment. | |
465 | */ | |
466 | if (skb_shinfo(skb)->frag_list) { | |
467 | struct sk_buff *frag; | |
468 | int first_len = skb_pagelen(skb); | |
469 | ||
470 | if (first_len - hlen > mtu || | |
471 | ((first_len - hlen) & 7) || | |
472 | (iph->frag_off & htons(IP_MF|IP_OFFSET)) || | |
473 | skb_cloned(skb)) | |
474 | goto slow_path; | |
475 | ||
476 | for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { | |
477 | /* Correct geometry. */ | |
478 | if (frag->len > mtu || | |
479 | ((frag->len & 7) && frag->next) || | |
480 | skb_headroom(frag) < hlen) | |
481 | goto slow_path; | |
482 | ||
483 | /* Partially cloned skb? */ | |
484 | if (skb_shared(frag)) | |
485 | goto slow_path; | |
2fdba6b0 HX |
486 | |
487 | BUG_ON(frag->sk); | |
488 | if (skb->sk) { | |
489 | sock_hold(skb->sk); | |
490 | frag->sk = skb->sk; | |
491 | frag->destructor = sock_wfree; | |
492 | skb->truesize -= frag->truesize; | |
493 | } | |
1da177e4 LT |
494 | } |
495 | ||
496 | /* Everything is OK. Generate! */ | |
497 | ||
498 | err = 0; | |
499 | offset = 0; | |
500 | frag = skb_shinfo(skb)->frag_list; | |
501 | skb_shinfo(skb)->frag_list = NULL; | |
502 | skb->data_len = first_len - skb_headlen(skb); | |
503 | skb->len = first_len; | |
504 | iph->tot_len = htons(first_len); | |
505 | iph->frag_off = htons(IP_MF); | |
506 | ip_send_check(iph); | |
507 | ||
508 | for (;;) { | |
509 | /* Prepare header of the next frame, | |
510 | * before previous one went down. */ | |
511 | if (frag) { | |
512 | frag->ip_summed = CHECKSUM_NONE; | |
513 | frag->h.raw = frag->data; | |
514 | frag->nh.raw = __skb_push(frag, hlen); | |
515 | memcpy(frag->nh.raw, iph, hlen); | |
516 | iph = frag->nh.iph; | |
517 | iph->tot_len = htons(frag->len); | |
518 | ip_copy_metadata(frag, skb); | |
519 | if (offset == 0) | |
520 | ip_options_fragment(frag); | |
521 | offset += skb->len - hlen; | |
522 | iph->frag_off = htons(offset>>3); | |
523 | if (frag->next != NULL) | |
524 | iph->frag_off |= htons(IP_MF); | |
525 | /* Ready, complete checksum */ | |
526 | ip_send_check(iph); | |
527 | } | |
528 | ||
529 | err = output(skb); | |
530 | ||
531 | if (err || !frag) | |
532 | break; | |
533 | ||
534 | skb = frag; | |
535 | frag = skb->next; | |
536 | skb->next = NULL; | |
537 | } | |
538 | ||
539 | if (err == 0) { | |
540 | IP_INC_STATS(IPSTATS_MIB_FRAGOKS); | |
541 | return 0; | |
542 | } | |
543 | ||
544 | while (frag) { | |
545 | skb = frag->next; | |
546 | kfree_skb(frag); | |
547 | frag = skb; | |
548 | } | |
549 | IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); | |
550 | return err; | |
551 | } | |
552 | ||
553 | slow_path: | |
554 | left = skb->len - hlen; /* Space per frame */ | |
555 | ptr = raw + hlen; /* Where to start from */ | |
556 | ||
557 | #ifdef CONFIG_BRIDGE_NETFILTER | |
558 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, | |
559 | * we need to make room for the encapsulating header */ | |
560 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb)); | |
561 | mtu -= nf_bridge_pad(skb); | |
562 | #else | |
563 | ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev); | |
564 | #endif | |
565 | /* | |
566 | * Fragment the datagram. | |
567 | */ | |
568 | ||
569 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
570 | not_last_frag = iph->frag_off & htons(IP_MF); | |
571 | ||
572 | /* | |
573 | * Keep copying data until we run out. | |
574 | */ | |
575 | ||
576 | while(left > 0) { | |
577 | len = left; | |
578 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
579 | if (len > mtu) | |
580 | len = mtu; | |
581 | /* IF: we are not sending upto and including the packet end | |
582 | then align the next start on an eight byte boundary */ | |
583 | if (len < left) { | |
584 | len &= ~7; | |
585 | } | |
586 | /* | |
587 | * Allocate buffer. | |
588 | */ | |
589 | ||
590 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { | |
64ce2073 | 591 | NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); |
1da177e4 LT |
592 | err = -ENOMEM; |
593 | goto fail; | |
594 | } | |
595 | ||
596 | /* | |
597 | * Set up data on packet | |
598 | */ | |
599 | ||
600 | ip_copy_metadata(skb2, skb); | |
601 | skb_reserve(skb2, ll_rs); | |
602 | skb_put(skb2, len + hlen); | |
603 | skb2->nh.raw = skb2->data; | |
604 | skb2->h.raw = skb2->data + hlen; | |
605 | ||
606 | /* | |
607 | * Charge the memory for the fragment to any owner | |
608 | * it might possess | |
609 | */ | |
610 | ||
611 | if (skb->sk) | |
612 | skb_set_owner_w(skb2, skb->sk); | |
613 | ||
614 | /* | |
615 | * Copy the packet header into the new buffer. | |
616 | */ | |
617 | ||
618 | memcpy(skb2->nh.raw, skb->data, hlen); | |
619 | ||
620 | /* | |
621 | * Copy a block of the IP datagram. | |
622 | */ | |
623 | if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) | |
624 | BUG(); | |
625 | left -= len; | |
626 | ||
627 | /* | |
628 | * Fill in the new header fields. | |
629 | */ | |
630 | iph = skb2->nh.iph; | |
631 | iph->frag_off = htons((offset >> 3)); | |
632 | ||
633 | /* ANK: dirty, but effective trick. Upgrade options only if | |
634 | * the segment to be fragmented was THE FIRST (otherwise, | |
635 | * options are already fixed) and make it ONCE | |
636 | * on the initial skb, so that all the following fragments | |
637 | * will inherit fixed options. | |
638 | */ | |
639 | if (offset == 0) | |
640 | ip_options_fragment(skb); | |
641 | ||
642 | /* | |
643 | * Added AC : If we are fragmenting a fragment that's not the | |
644 | * last fragment then keep MF on each bit | |
645 | */ | |
646 | if (left > 0 || not_last_frag) | |
647 | iph->frag_off |= htons(IP_MF); | |
648 | ptr += len; | |
649 | offset += len; | |
650 | ||
651 | /* | |
652 | * Put this fragment into the sending queue. | |
653 | */ | |
654 | ||
655 | IP_INC_STATS(IPSTATS_MIB_FRAGCREATES); | |
656 | ||
657 | iph->tot_len = htons(len + hlen); | |
658 | ||
659 | ip_send_check(iph); | |
660 | ||
661 | err = output(skb2); | |
662 | if (err) | |
663 | goto fail; | |
664 | } | |
665 | kfree_skb(skb); | |
666 | IP_INC_STATS(IPSTATS_MIB_FRAGOKS); | |
667 | return err; | |
668 | ||
669 | fail: | |
670 | kfree_skb(skb); | |
671 | IP_INC_STATS(IPSTATS_MIB_FRAGFAILS); | |
672 | return err; | |
673 | } | |
674 | ||
2e2f7aef PM |
675 | EXPORT_SYMBOL(ip_fragment); |
676 | ||
1da177e4 LT |
677 | int |
678 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
679 | { | |
680 | struct iovec *iov = from; | |
681 | ||
682 | if (skb->ip_summed == CHECKSUM_HW) { | |
683 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) | |
684 | return -EFAULT; | |
685 | } else { | |
686 | unsigned int csum = 0; | |
687 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) | |
688 | return -EFAULT; | |
689 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
690 | } | |
691 | return 0; | |
692 | } | |
693 | ||
694 | static inline unsigned int | |
695 | csum_page(struct page *page, int offset, int copy) | |
696 | { | |
697 | char *kaddr; | |
698 | unsigned int csum; | |
699 | kaddr = kmap(page); | |
700 | csum = csum_partial(kaddr + offset, copy, 0); | |
701 | kunmap(page); | |
702 | return csum; | |
703 | } | |
704 | ||
4b30b1c6 | 705 | static inline int ip_ufo_append_data(struct sock *sk, |
e89e9cf5 AR |
706 | int getfrag(void *from, char *to, int offset, int len, |
707 | int odd, struct sk_buff *skb), | |
708 | void *from, int length, int hh_len, int fragheaderlen, | |
709 | int transhdrlen, int mtu,unsigned int flags) | |
710 | { | |
711 | struct sk_buff *skb; | |
712 | int err; | |
713 | ||
714 | /* There is support for UDP fragmentation offload by network | |
715 | * device, so create one single skb packet containing complete | |
716 | * udp datagram | |
717 | */ | |
718 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { | |
719 | skb = sock_alloc_send_skb(sk, | |
720 | hh_len + fragheaderlen + transhdrlen + 20, | |
721 | (flags & MSG_DONTWAIT), &err); | |
722 | ||
723 | if (skb == NULL) | |
724 | return err; | |
725 | ||
726 | /* reserve space for Hardware header */ | |
727 | skb_reserve(skb, hh_len); | |
728 | ||
729 | /* create space for UDP/IP header */ | |
730 | skb_put(skb,fragheaderlen + transhdrlen); | |
731 | ||
732 | /* initialize network header pointer */ | |
733 | skb->nh.raw = skb->data; | |
734 | ||
735 | /* initialize protocol header pointer */ | |
736 | skb->h.raw = skb->data + fragheaderlen; | |
737 | ||
738 | skb->ip_summed = CHECKSUM_HW; | |
739 | skb->csum = 0; | |
740 | sk->sk_sndmsg_off = 0; | |
741 | } | |
742 | ||
743 | err = skb_append_datato_frags(sk,skb, getfrag, from, | |
744 | (length - transhdrlen)); | |
745 | if (!err) { | |
746 | /* specify the length of each IP datagram fragment*/ | |
747 | skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen); | |
748 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
749 | ||
750 | return 0; | |
751 | } | |
752 | /* There is not enough support do UFO , | |
753 | * so follow normal path | |
754 | */ | |
755 | kfree_skb(skb); | |
756 | return err; | |
757 | } | |
758 | ||
1da177e4 LT |
759 | /* |
760 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
761 | * from many pieces of data. Each pieces will be holded on the socket | |
762 | * until ip_push_pending_frames() is called. Each piece can be a page | |
763 | * or non-page data. | |
764 | * | |
765 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
766 | * this interface potentially. | |
767 | * | |
768 | * LATER: length must be adjusted by pad at tail, when it is required. | |
769 | */ | |
770 | int ip_append_data(struct sock *sk, | |
771 | int getfrag(void *from, char *to, int offset, int len, | |
772 | int odd, struct sk_buff *skb), | |
773 | void *from, int length, int transhdrlen, | |
774 | struct ipcm_cookie *ipc, struct rtable *rt, | |
775 | unsigned int flags) | |
776 | { | |
777 | struct inet_sock *inet = inet_sk(sk); | |
778 | struct sk_buff *skb; | |
779 | ||
780 | struct ip_options *opt = NULL; | |
781 | int hh_len; | |
782 | int exthdrlen; | |
783 | int mtu; | |
784 | int copy; | |
785 | int err; | |
786 | int offset = 0; | |
787 | unsigned int maxfraglen, fragheaderlen; | |
788 | int csummode = CHECKSUM_NONE; | |
789 | ||
790 | if (flags&MSG_PROBE) | |
791 | return 0; | |
792 | ||
793 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
794 | /* | |
795 | * setup for corking. | |
796 | */ | |
797 | opt = ipc->opt; | |
798 | if (opt) { | |
799 | if (inet->cork.opt == NULL) { | |
800 | inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); | |
801 | if (unlikely(inet->cork.opt == NULL)) | |
802 | return -ENOBUFS; | |
803 | } | |
804 | memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); | |
805 | inet->cork.flags |= IPCORK_OPT; | |
806 | inet->cork.addr = ipc->addr; | |
807 | } | |
808 | dst_hold(&rt->u.dst); | |
809 | inet->cork.fragsize = mtu = dst_mtu(rt->u.dst.path); | |
810 | inet->cork.rt = rt; | |
811 | inet->cork.length = 0; | |
812 | sk->sk_sndmsg_page = NULL; | |
813 | sk->sk_sndmsg_off = 0; | |
814 | if ((exthdrlen = rt->u.dst.header_len) != 0) { | |
815 | length += exthdrlen; | |
816 | transhdrlen += exthdrlen; | |
817 | } | |
818 | } else { | |
819 | rt = inet->cork.rt; | |
820 | if (inet->cork.flags & IPCORK_OPT) | |
821 | opt = inet->cork.opt; | |
822 | ||
823 | transhdrlen = 0; | |
824 | exthdrlen = 0; | |
825 | mtu = inet->cork.fragsize; | |
826 | } | |
827 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
828 | ||
829 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
830 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
831 | ||
832 | if (inet->cork.length + length > 0xFFFF - fragheaderlen) { | |
833 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, 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 && | |
8648b305 | 843 | rt->u.dst.dev->features & NETIF_F_ALL_CSUM && |
1da177e4 LT |
844 | !exthdrlen) |
845 | csummode = CHECKSUM_HW; | |
846 | ||
847 | inet->cork.length += length; | |
e89e9cf5 AR |
848 | if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && |
849 | (rt->u.dst.dev->features & NETIF_F_UFO)) { | |
850 | ||
baa829d8 PM |
851 | err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, |
852 | fragheaderlen, transhdrlen, mtu, | |
853 | flags); | |
854 | if (err) | |
e89e9cf5 | 855 | goto error; |
e89e9cf5 AR |
856 | return 0; |
857 | } | |
1da177e4 LT |
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 = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
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->u.dst.dev->features&NETIF_F_SG)) | |
899 | alloclen = mtu; | |
900 | else | |
901 | alloclen = datalen + fragheaderlen; | |
902 | ||
903 | /* The last fragment gets additional space at tail. | |
904 | * Note, with MSG_MORE we overallocate on fragments, | |
905 | * because we have no idea what fragment will be | |
906 | * the last. | |
907 | */ | |
3d9dd756 | 908 | if (datalen == length + fraggap) |
1da177e4 LT |
909 | alloclen += rt->u.dst.trailer_len; |
910 | ||
911 | if (transhdrlen) { | |
912 | skb = sock_alloc_send_skb(sk, | |
913 | alloclen + hh_len + 15, | |
914 | (flags & MSG_DONTWAIT), &err); | |
915 | } else { | |
916 | skb = NULL; | |
917 | if (atomic_read(&sk->sk_wmem_alloc) <= | |
918 | 2 * sk->sk_sndbuf) | |
919 | skb = sock_wmalloc(sk, | |
920 | alloclen + hh_len + 15, 1, | |
921 | sk->sk_allocation); | |
922 | if (unlikely(skb == NULL)) | |
923 | err = -ENOBUFS; | |
924 | } | |
925 | if (skb == NULL) | |
926 | goto error; | |
927 | ||
928 | /* | |
929 | * Fill in the control structures | |
930 | */ | |
931 | skb->ip_summed = csummode; | |
932 | skb->csum = 0; | |
933 | skb_reserve(skb, hh_len); | |
934 | ||
935 | /* | |
936 | * Find where to start putting bytes. | |
937 | */ | |
938 | data = skb_put(skb, fraglen); | |
939 | skb->nh.raw = data + exthdrlen; | |
940 | data += fragheaderlen; | |
941 | skb->h.raw = data + exthdrlen; | |
942 | ||
943 | if (fraggap) { | |
944 | skb->csum = skb_copy_and_csum_bits( | |
945 | skb_prev, maxfraglen, | |
946 | data + transhdrlen, fraggap, 0); | |
947 | skb_prev->csum = csum_sub(skb_prev->csum, | |
948 | skb->csum); | |
949 | data += fraggap; | |
950 | skb_trim(skb_prev, maxfraglen); | |
951 | } | |
952 | ||
953 | copy = datalen - transhdrlen - fraggap; | |
954 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
955 | err = -EFAULT; | |
956 | kfree_skb(skb); | |
957 | goto error; | |
958 | } | |
959 | ||
960 | offset += copy; | |
961 | length -= datalen - fraggap; | |
962 | transhdrlen = 0; | |
963 | exthdrlen = 0; | |
964 | csummode = CHECKSUM_NONE; | |
965 | ||
966 | /* | |
967 | * Put the packet on the pending queue. | |
968 | */ | |
969 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
970 | continue; | |
971 | } | |
972 | ||
973 | if (copy > length) | |
974 | copy = length; | |
975 | ||
976 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) { | |
977 | unsigned int off; | |
978 | ||
979 | off = skb->len; | |
980 | if (getfrag(from, skb_put(skb, copy), | |
981 | offset, copy, off, skb) < 0) { | |
982 | __skb_trim(skb, off); | |
983 | err = -EFAULT; | |
984 | goto error; | |
985 | } | |
986 | } else { | |
987 | int i = skb_shinfo(skb)->nr_frags; | |
988 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; | |
989 | struct page *page = sk->sk_sndmsg_page; | |
990 | int off = sk->sk_sndmsg_off; | |
991 | unsigned int left; | |
992 | ||
993 | if (page && (left = PAGE_SIZE - off) > 0) { | |
994 | if (copy >= left) | |
995 | copy = left; | |
996 | if (page != frag->page) { | |
997 | if (i == MAX_SKB_FRAGS) { | |
998 | err = -EMSGSIZE; | |
999 | goto error; | |
1000 | } | |
1001 | get_page(page); | |
1002 | skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); | |
1003 | frag = &skb_shinfo(skb)->frags[i]; | |
1004 | } | |
1005 | } else if (i < MAX_SKB_FRAGS) { | |
1006 | if (copy > PAGE_SIZE) | |
1007 | copy = PAGE_SIZE; | |
1008 | page = alloc_pages(sk->sk_allocation, 0); | |
1009 | if (page == NULL) { | |
1010 | err = -ENOMEM; | |
1011 | goto error; | |
1012 | } | |
1013 | sk->sk_sndmsg_page = page; | |
1014 | sk->sk_sndmsg_off = 0; | |
1015 | ||
1016 | skb_fill_page_desc(skb, i, page, 0, 0); | |
1017 | frag = &skb_shinfo(skb)->frags[i]; | |
1018 | skb->truesize += PAGE_SIZE; | |
1019 | atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); | |
1020 | } else { | |
1021 | err = -EMSGSIZE; | |
1022 | goto error; | |
1023 | } | |
1024 | if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { | |
1025 | err = -EFAULT; | |
1026 | goto error; | |
1027 | } | |
1028 | sk->sk_sndmsg_off += copy; | |
1029 | frag->size += copy; | |
1030 | skb->len += copy; | |
1031 | skb->data_len += copy; | |
1032 | } | |
1033 | offset += copy; | |
1034 | length -= copy; | |
1035 | } | |
1036 | ||
1037 | return 0; | |
1038 | ||
1039 | error: | |
1040 | inet->cork.length -= length; | |
1041 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
1042 | return err; | |
1043 | } | |
1044 | ||
1045 | ssize_t ip_append_page(struct sock *sk, struct page *page, | |
1046 | int offset, size_t size, int flags) | |
1047 | { | |
1048 | struct inet_sock *inet = inet_sk(sk); | |
1049 | struct sk_buff *skb; | |
1050 | struct rtable *rt; | |
1051 | struct ip_options *opt = NULL; | |
1052 | int hh_len; | |
1053 | int mtu; | |
1054 | int len; | |
1055 | int err; | |
1056 | unsigned int maxfraglen, fragheaderlen, fraggap; | |
1057 | ||
1058 | if (inet->hdrincl) | |
1059 | return -EPERM; | |
1060 | ||
1061 | if (flags&MSG_PROBE) | |
1062 | return 0; | |
1063 | ||
1064 | if (skb_queue_empty(&sk->sk_write_queue)) | |
1065 | return -EINVAL; | |
1066 | ||
1067 | rt = inet->cork.rt; | |
1068 | if (inet->cork.flags & IPCORK_OPT) | |
1069 | opt = inet->cork.opt; | |
1070 | ||
1071 | if (!(rt->u.dst.dev->features&NETIF_F_SG)) | |
1072 | return -EOPNOTSUPP; | |
1073 | ||
1074 | hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); | |
1075 | mtu = inet->cork.fragsize; | |
1076 | ||
1077 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1078 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1079 | ||
1080 | if (inet->cork.length + size > 0xFFFF - fragheaderlen) { | |
1081 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); | |
1082 | return -EMSGSIZE; | |
1083 | } | |
1084 | ||
1085 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
1086 | return -EINVAL; | |
1087 | ||
1088 | inet->cork.length += size; | |
e89e9cf5 AR |
1089 | if ((sk->sk_protocol == IPPROTO_UDP) && |
1090 | (rt->u.dst.dev->features & NETIF_F_UFO)) | |
1091 | skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen); | |
1092 | ||
1da177e4 LT |
1093 | |
1094 | while (size > 0) { | |
1095 | int i; | |
1096 | ||
e89e9cf5 AR |
1097 | if (skb_shinfo(skb)->ufo_size) |
1098 | len = size; | |
1099 | else { | |
1100 | ||
1101 | /* Check if the remaining data fits into current packet. */ | |
1102 | len = mtu - skb->len; | |
1103 | if (len < size) | |
1104 | len = maxfraglen - skb->len; | |
1105 | } | |
1da177e4 LT |
1106 | if (len <= 0) { |
1107 | struct sk_buff *skb_prev; | |
1108 | char *data; | |
1109 | struct iphdr *iph; | |
1110 | int alloclen; | |
1111 | ||
1112 | skb_prev = skb; | |
0d0d2bba | 1113 | fraggap = skb_prev->len - maxfraglen; |
1da177e4 LT |
1114 | |
1115 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1116 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1117 | if (unlikely(!skb)) { | |
1118 | err = -ENOBUFS; | |
1119 | goto error; | |
1120 | } | |
1121 | ||
1122 | /* | |
1123 | * Fill in the control structures | |
1124 | */ | |
1125 | skb->ip_summed = CHECKSUM_NONE; | |
1126 | skb->csum = 0; | |
1127 | skb_reserve(skb, hh_len); | |
1128 | ||
1129 | /* | |
1130 | * Find where to start putting bytes. | |
1131 | */ | |
1132 | data = skb_put(skb, fragheaderlen + fraggap); | |
1133 | skb->nh.iph = iph = (struct iphdr *)data; | |
1134 | data += fragheaderlen; | |
1135 | skb->h.raw = data; | |
1136 | ||
1137 | if (fraggap) { | |
1138 | skb->csum = skb_copy_and_csum_bits( | |
1139 | skb_prev, maxfraglen, | |
1140 | data, fraggap, 0); | |
1141 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1142 | skb->csum); | |
1143 | skb_trim(skb_prev, maxfraglen); | |
1144 | } | |
1145 | ||
1146 | /* | |
1147 | * Put the packet on the pending queue. | |
1148 | */ | |
1149 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1150 | continue; | |
1151 | } | |
1152 | ||
1153 | i = skb_shinfo(skb)->nr_frags; | |
1154 | if (len > size) | |
1155 | len = size; | |
1156 | if (skb_can_coalesce(skb, i, page, offset)) { | |
1157 | skb_shinfo(skb)->frags[i-1].size += len; | |
1158 | } else if (i < MAX_SKB_FRAGS) { | |
1159 | get_page(page); | |
1160 | skb_fill_page_desc(skb, i, page, offset, len); | |
1161 | } else { | |
1162 | err = -EMSGSIZE; | |
1163 | goto error; | |
1164 | } | |
1165 | ||
1166 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1167 | unsigned int csum; | |
1168 | csum = csum_page(page, offset, len); | |
1169 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1170 | } | |
1171 | ||
1172 | skb->len += len; | |
1173 | skb->data_len += len; | |
1174 | offset += len; | |
1175 | size -= len; | |
1176 | } | |
1177 | return 0; | |
1178 | ||
1179 | error: | |
1180 | inet->cork.length -= size; | |
1181 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
1182 | return err; | |
1183 | } | |
1184 | ||
1185 | /* | |
1186 | * Combined all pending IP fragments on the socket as one IP datagram | |
1187 | * and push them out. | |
1188 | */ | |
1189 | int ip_push_pending_frames(struct sock *sk) | |
1190 | { | |
1191 | struct sk_buff *skb, *tmp_skb; | |
1192 | struct sk_buff **tail_skb; | |
1193 | struct inet_sock *inet = inet_sk(sk); | |
1194 | struct ip_options *opt = NULL; | |
1195 | struct rtable *rt = inet->cork.rt; | |
1196 | struct iphdr *iph; | |
76ab608d | 1197 | __be16 df = 0; |
1da177e4 LT |
1198 | __u8 ttl; |
1199 | int err = 0; | |
1200 | ||
1201 | if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) | |
1202 | goto out; | |
1203 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1204 | ||
1205 | /* move skb->data to ip header from ext header */ | |
1206 | if (skb->data < skb->nh.raw) | |
1207 | __skb_pull(skb, skb->nh.raw - skb->data); | |
1208 | while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { | |
1209 | __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw); | |
1210 | *tail_skb = tmp_skb; | |
1211 | tail_skb = &(tmp_skb->next); | |
1212 | skb->len += tmp_skb->len; | |
1213 | skb->data_len += tmp_skb->len; | |
1214 | skb->truesize += tmp_skb->truesize; | |
1215 | __sock_put(tmp_skb->sk); | |
1216 | tmp_skb->destructor = NULL; | |
1217 | tmp_skb->sk = NULL; | |
1218 | } | |
1219 | ||
1220 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1221 | * to fragment the frame generated here. No matter, what transforms | |
1222 | * how transforms change size of the packet, it will come out. | |
1223 | */ | |
1224 | if (inet->pmtudisc != IP_PMTUDISC_DO) | |
1225 | skb->local_df = 1; | |
1226 | ||
1227 | /* DF bit is set when we want to see DF on outgoing frames. | |
1228 | * If local_df is set too, we still allow to fragment this frame | |
1229 | * locally. */ | |
1230 | if (inet->pmtudisc == IP_PMTUDISC_DO || | |
1231 | (skb->len <= dst_mtu(&rt->u.dst) && | |
1232 | ip_dont_fragment(sk, &rt->u.dst))) | |
1233 | df = htons(IP_DF); | |
1234 | ||
1235 | if (inet->cork.flags & IPCORK_OPT) | |
1236 | opt = inet->cork.opt; | |
1237 | ||
1238 | if (rt->rt_type == RTN_MULTICAST) | |
1239 | ttl = inet->mc_ttl; | |
1240 | else | |
1241 | ttl = ip_select_ttl(inet, &rt->u.dst); | |
1242 | ||
1243 | iph = (struct iphdr *)skb->data; | |
1244 | iph->version = 4; | |
1245 | iph->ihl = 5; | |
1246 | if (opt) { | |
1247 | iph->ihl += opt->optlen>>2; | |
1248 | ip_options_build(skb, opt, inet->cork.addr, rt, 0); | |
1249 | } | |
1250 | iph->tos = inet->tos; | |
1251 | iph->tot_len = htons(skb->len); | |
1252 | iph->frag_off = df; | |
1a55d57b | 1253 | ip_select_ident(iph, &rt->u.dst, sk); |
1da177e4 LT |
1254 | iph->ttl = ttl; |
1255 | iph->protocol = sk->sk_protocol; | |
1256 | iph->saddr = rt->rt_src; | |
1257 | iph->daddr = rt->rt_dst; | |
1258 | ip_send_check(iph); | |
1259 | ||
1260 | skb->priority = sk->sk_priority; | |
1261 | skb->dst = dst_clone(&rt->u.dst); | |
1262 | ||
1263 | /* Netfilter gets whole the not fragmented skb. */ | |
1264 | err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, | |
1265 | skb->dst->dev, dst_output); | |
1266 | if (err) { | |
1267 | if (err > 0) | |
1268 | err = inet->recverr ? net_xmit_errno(err) : 0; | |
1269 | if (err) | |
1270 | goto error; | |
1271 | } | |
1272 | ||
1273 | out: | |
1274 | inet->cork.flags &= ~IPCORK_OPT; | |
a51482bd JJ |
1275 | kfree(inet->cork.opt); |
1276 | inet->cork.opt = NULL; | |
1da177e4 LT |
1277 | if (inet->cork.rt) { |
1278 | ip_rt_put(inet->cork.rt); | |
1279 | inet->cork.rt = NULL; | |
1280 | } | |
1281 | return err; | |
1282 | ||
1283 | error: | |
1284 | IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS); | |
1285 | goto out; | |
1286 | } | |
1287 | ||
1288 | /* | |
1289 | * Throw away all pending data on the socket. | |
1290 | */ | |
1291 | void ip_flush_pending_frames(struct sock *sk) | |
1292 | { | |
1293 | struct inet_sock *inet = inet_sk(sk); | |
1294 | struct sk_buff *skb; | |
1295 | ||
1296 | while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) | |
1297 | kfree_skb(skb); | |
1298 | ||
1299 | inet->cork.flags &= ~IPCORK_OPT; | |
a51482bd JJ |
1300 | kfree(inet->cork.opt); |
1301 | inet->cork.opt = NULL; | |
1da177e4 LT |
1302 | if (inet->cork.rt) { |
1303 | ip_rt_put(inet->cork.rt); | |
1304 | inet->cork.rt = NULL; | |
1305 | } | |
1306 | } | |
1307 | ||
1308 | ||
1309 | /* | |
1310 | * Fetch data from kernel space and fill in checksum if needed. | |
1311 | */ | |
1312 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, | |
1313 | int len, int odd, struct sk_buff *skb) | |
1314 | { | |
1315 | unsigned int csum; | |
1316 | ||
1317 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); | |
1318 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
1319 | return 0; | |
1320 | } | |
1321 | ||
1322 | /* | |
1323 | * Generic function to send a packet as reply to another packet. | |
1324 | * Used to send TCP resets so far. ICMP should use this function too. | |
1325 | * | |
1326 | * Should run single threaded per socket because it uses the sock | |
1327 | * structure to pass arguments. | |
1328 | * | |
1329 | * LATER: switch from ip_build_xmit to ip_append_* | |
1330 | */ | |
1331 | void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, | |
1332 | unsigned int len) | |
1333 | { | |
1334 | struct inet_sock *inet = inet_sk(sk); | |
1335 | struct { | |
1336 | struct ip_options opt; | |
1337 | char data[40]; | |
1338 | } replyopts; | |
1339 | struct ipcm_cookie ipc; | |
1340 | u32 daddr; | |
1341 | struct rtable *rt = (struct rtable*)skb->dst; | |
1342 | ||
1343 | if (ip_options_echo(&replyopts.opt, skb)) | |
1344 | return; | |
1345 | ||
1346 | daddr = ipc.addr = rt->rt_src; | |
1347 | ipc.opt = NULL; | |
1348 | ||
1349 | if (replyopts.opt.optlen) { | |
1350 | ipc.opt = &replyopts.opt; | |
1351 | ||
1352 | if (ipc.opt->srr) | |
1353 | daddr = replyopts.opt.faddr; | |
1354 | } | |
1355 | ||
1356 | { | |
1357 | struct flowi fl = { .nl_u = { .ip4_u = | |
1358 | { .daddr = daddr, | |
1359 | .saddr = rt->rt_spec_dst, | |
1360 | .tos = RT_TOS(skb->nh.iph->tos) } }, | |
1361 | /* Not quite clean, but right. */ | |
1362 | .uli_u = { .ports = | |
1363 | { .sport = skb->h.th->dest, | |
1364 | .dport = skb->h.th->source } }, | |
1365 | .proto = sk->sk_protocol }; | |
1366 | if (ip_route_output_key(&rt, &fl)) | |
1367 | return; | |
1368 | } | |
1369 | ||
1370 | /* And let IP do all the hard work. | |
1371 | ||
1372 | This chunk is not reenterable, hence spinlock. | |
1373 | Note that it uses the fact, that this function is called | |
1374 | with locally disabled BH and that sk cannot be already spinlocked. | |
1375 | */ | |
1376 | bh_lock_sock(sk); | |
1377 | inet->tos = skb->nh.iph->tos; | |
1378 | sk->sk_priority = skb->priority; | |
1379 | sk->sk_protocol = skb->nh.iph->protocol; | |
1380 | ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, | |
1381 | &ipc, rt, MSG_DONTWAIT); | |
1382 | if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { | |
1383 | if (arg->csumoffset >= 0) | |
1384 | *((u16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum)); | |
1385 | skb->ip_summed = CHECKSUM_NONE; | |
1386 | ip_push_pending_frames(sk); | |
1387 | } | |
1388 | ||
1389 | bh_unlock_sock(sk); | |
1390 | ||
1391 | ip_rt_put(rt); | |
1392 | } | |
1393 | ||
1da177e4 LT |
1394 | void __init ip_init(void) |
1395 | { | |
1da177e4 LT |
1396 | ip_rt_init(); |
1397 | inet_initpeers(); | |
1398 | ||
1399 | #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) | |
1400 | igmp_mc_proc_init(); | |
1401 | #endif | |
1402 | } | |
1403 | ||
1da177e4 LT |
1404 | EXPORT_SYMBOL(ip_generic_getfrag); |
1405 | EXPORT_SYMBOL(ip_queue_xmit); | |
1406 | EXPORT_SYMBOL(ip_send_check); |