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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 | #include <linux/slab.h> | |
55 | ||
56 | #include <linux/socket.h> | |
57 | #include <linux/sockios.h> | |
58 | #include <linux/in.h> | |
59 | #include <linux/inet.h> | |
60 | #include <linux/netdevice.h> | |
61 | #include <linux/etherdevice.h> | |
62 | #include <linux/proc_fs.h> | |
63 | #include <linux/stat.h> | |
64 | #include <linux/init.h> | |
65 | ||
66 | #include <net/snmp.h> | |
67 | #include <net/ip.h> | |
68 | #include <net/protocol.h> | |
69 | #include <net/route.h> | |
70 | #include <net/xfrm.h> | |
71 | #include <linux/skbuff.h> | |
72 | #include <net/sock.h> | |
73 | #include <net/arp.h> | |
74 | #include <net/icmp.h> | |
75 | #include <net/checksum.h> | |
76 | #include <net/inetpeer.h> | |
77 | #include <linux/igmp.h> | |
78 | #include <linux/netfilter_ipv4.h> | |
79 | #include <linux/netfilter_bridge.h> | |
80 | #include <linux/mroute.h> | |
81 | #include <linux/netlink.h> | |
82 | #include <linux/tcp.h> | |
83 | ||
84 | int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; | |
85 | ||
86 | /* Generate a checksum for an outgoing IP datagram. */ | |
87 | __inline__ void ip_send_check(struct iphdr *iph) | |
88 | { | |
89 | iph->check = 0; | |
90 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
91 | } | |
92 | EXPORT_SYMBOL(ip_send_check); | |
93 | ||
94 | int __ip_local_out(struct sk_buff *skb) | |
95 | { | |
96 | struct iphdr *iph = ip_hdr(skb); | |
97 | ||
98 | iph->tot_len = htons(skb->len); | |
99 | ip_send_check(iph); | |
100 | return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, skb, NULL, | |
101 | skb_dst(skb)->dev, dst_output); | |
102 | } | |
103 | ||
104 | int ip_local_out(struct sk_buff *skb) | |
105 | { | |
106 | int err; | |
107 | ||
108 | err = __ip_local_out(skb); | |
109 | if (likely(err == 1)) | |
110 | err = dst_output(skb); | |
111 | ||
112 | return err; | |
113 | } | |
114 | EXPORT_SYMBOL_GPL(ip_local_out); | |
115 | ||
116 | /* dev_loopback_xmit for use with netfilter. */ | |
117 | static int ip_dev_loopback_xmit(struct sk_buff *newskb) | |
118 | { | |
119 | skb_reset_mac_header(newskb); | |
120 | __skb_pull(newskb, skb_network_offset(newskb)); | |
121 | newskb->pkt_type = PACKET_LOOPBACK; | |
122 | newskb->ip_summed = CHECKSUM_UNNECESSARY; | |
123 | WARN_ON(!skb_dst(newskb)); | |
124 | netif_rx_ni(newskb); | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) | |
129 | { | |
130 | int ttl = inet->uc_ttl; | |
131 | ||
132 | if (ttl < 0) | |
133 | ttl = dst_metric(dst, RTAX_HOPLIMIT); | |
134 | return ttl; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Add an ip header to a skbuff and send it out. | |
139 | * | |
140 | */ | |
141 | int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, | |
142 | __be32 saddr, __be32 daddr, struct ip_options *opt) | |
143 | { | |
144 | struct inet_sock *inet = inet_sk(sk); | |
145 | struct rtable *rt = skb_rtable(skb); | |
146 | struct iphdr *iph; | |
147 | ||
148 | /* Build the IP header. */ | |
149 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
150 | skb_reset_network_header(skb); | |
151 | iph = ip_hdr(skb); | |
152 | iph->version = 4; | |
153 | iph->ihl = 5; | |
154 | iph->tos = inet->tos; | |
155 | if (ip_dont_fragment(sk, &rt->dst)) | |
156 | iph->frag_off = htons(IP_DF); | |
157 | else | |
158 | iph->frag_off = 0; | |
159 | iph->ttl = ip_select_ttl(inet, &rt->dst); | |
160 | iph->daddr = rt->rt_dst; | |
161 | iph->saddr = rt->rt_src; | |
162 | iph->protocol = sk->sk_protocol; | |
163 | ip_select_ident(iph, &rt->dst, sk); | |
164 | ||
165 | if (opt && opt->optlen) { | |
166 | iph->ihl += opt->optlen>>2; | |
167 | ip_options_build(skb, opt, daddr, rt, 0); | |
168 | } | |
169 | ||
170 | skb->priority = sk->sk_priority; | |
171 | skb->mark = sk->sk_mark; | |
172 | ||
173 | /* Send it out. */ | |
174 | return ip_local_out(skb); | |
175 | } | |
176 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); | |
177 | ||
178 | static inline int ip_finish_output2(struct sk_buff *skb) | |
179 | { | |
180 | struct dst_entry *dst = skb_dst(skb); | |
181 | struct rtable *rt = (struct rtable *)dst; | |
182 | struct net_device *dev = dst->dev; | |
183 | unsigned int hh_len = LL_RESERVED_SPACE(dev); | |
184 | ||
185 | if (rt->rt_type == RTN_MULTICAST) { | |
186 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len); | |
187 | } else if (rt->rt_type == RTN_BROADCAST) | |
188 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len); | |
189 | ||
190 | /* Be paranoid, rather than too clever. */ | |
191 | if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { | |
192 | struct sk_buff *skb2; | |
193 | ||
194 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
195 | if (skb2 == NULL) { | |
196 | kfree_skb(skb); | |
197 | return -ENOMEM; | |
198 | } | |
199 | if (skb->sk) | |
200 | skb_set_owner_w(skb2, skb->sk); | |
201 | kfree_skb(skb); | |
202 | skb = skb2; | |
203 | } | |
204 | ||
205 | if (dst->hh) | |
206 | return neigh_hh_output(dst->hh, 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 | static inline int ip_skb_dst_mtu(struct sk_buff *skb) | |
217 | { | |
218 | struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL; | |
219 | ||
220 | return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ? | |
221 | skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb)); | |
222 | } | |
223 | ||
224 | static int ip_finish_output(struct sk_buff *skb) | |
225 | { | |
226 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) | |
227 | /* Policy lookup after SNAT yielded a new policy */ | |
228 | if (skb_dst(skb)->xfrm != NULL) { | |
229 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
230 | return dst_output(skb); | |
231 | } | |
232 | #endif | |
233 | if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb)) | |
234 | return ip_fragment(skb, ip_finish_output2); | |
235 | else | |
236 | return ip_finish_output2(skb); | |
237 | } | |
238 | ||
239 | int ip_mc_output(struct sk_buff *skb) | |
240 | { | |
241 | struct sock *sk = skb->sk; | |
242 | struct rtable *rt = skb_rtable(skb); | |
243 | struct net_device *dev = rt->dst.dev; | |
244 | ||
245 | /* | |
246 | * If the indicated interface is up and running, send the packet. | |
247 | */ | |
248 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); | |
249 | ||
250 | skb->dev = dev; | |
251 | skb->protocol = htons(ETH_P_IP); | |
252 | ||
253 | /* | |
254 | * Multicasts are looped back for other local users | |
255 | */ | |
256 | ||
257 | if (rt->rt_flags&RTCF_MULTICAST) { | |
258 | if (sk_mc_loop(sk) | |
259 | #ifdef CONFIG_IP_MROUTE | |
260 | /* Small optimization: do not loopback not local frames, | |
261 | which returned after forwarding; they will be dropped | |
262 | by ip_mr_input in any case. | |
263 | Note, that local frames are looped back to be delivered | |
264 | to local recipients. | |
265 | ||
266 | This check is duplicated in ip_mr_input at the moment. | |
267 | */ | |
268 | && | |
269 | ((rt->rt_flags & RTCF_LOCAL) || | |
270 | !(IPCB(skb)->flags & IPSKB_FORWARDED)) | |
271 | #endif | |
272 | ) { | |
273 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
274 | if (newskb) | |
275 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, | |
276 | newskb, NULL, newskb->dev, | |
277 | ip_dev_loopback_xmit); | |
278 | } | |
279 | ||
280 | /* Multicasts with ttl 0 must not go beyond the host */ | |
281 | ||
282 | if (ip_hdr(skb)->ttl == 0) { | |
283 | kfree_skb(skb); | |
284 | return 0; | |
285 | } | |
286 | } | |
287 | ||
288 | if (rt->rt_flags&RTCF_BROADCAST) { | |
289 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
290 | if (newskb) | |
291 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb, | |
292 | NULL, newskb->dev, ip_dev_loopback_xmit); | |
293 | } | |
294 | ||
295 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, | |
296 | skb->dev, ip_finish_output, | |
297 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
298 | } | |
299 | ||
300 | int ip_output(struct sk_buff *skb) | |
301 | { | |
302 | struct net_device *dev = skb_dst(skb)->dev; | |
303 | ||
304 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); | |
305 | ||
306 | skb->dev = dev; | |
307 | skb->protocol = htons(ETH_P_IP); | |
308 | ||
309 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev, | |
310 | ip_finish_output, | |
311 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
312 | } | |
313 | ||
314 | int ip_queue_xmit(struct sk_buff *skb) | |
315 | { | |
316 | struct sock *sk = skb->sk; | |
317 | struct inet_sock *inet = inet_sk(sk); | |
318 | struct ip_options *opt = inet->opt; | |
319 | struct rtable *rt; | |
320 | struct iphdr *iph; | |
321 | int res; | |
322 | ||
323 | /* Skip all of this if the packet is already routed, | |
324 | * f.e. by something like SCTP. | |
325 | */ | |
326 | rcu_read_lock(); | |
327 | rt = skb_rtable(skb); | |
328 | if (rt != NULL) | |
329 | goto packet_routed; | |
330 | ||
331 | /* Make sure we can route this packet. */ | |
332 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
333 | if (rt == NULL) { | |
334 | __be32 daddr; | |
335 | ||
336 | /* Use correct destination address if we have options. */ | |
337 | daddr = inet->inet_daddr; | |
338 | if(opt && opt->srr) | |
339 | daddr = opt->faddr; | |
340 | ||
341 | { | |
342 | struct flowi fl = { .oif = sk->sk_bound_dev_if, | |
343 | .mark = sk->sk_mark, | |
344 | .fl4_dst = daddr, | |
345 | .fl4_src = inet->inet_saddr, | |
346 | .fl4_tos = RT_CONN_FLAGS(sk), | |
347 | .proto = sk->sk_protocol, | |
348 | .flags = inet_sk_flowi_flags(sk), | |
349 | .fl_ip_sport = inet->inet_sport, | |
350 | .fl_ip_dport = inet->inet_dport }; | |
351 | ||
352 | /* If this fails, retransmit mechanism of transport layer will | |
353 | * keep trying until route appears or the connection times | |
354 | * itself out. | |
355 | */ | |
356 | security_sk_classify_flow(sk, &fl); | |
357 | if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0)) | |
358 | goto no_route; | |
359 | } | |
360 | sk_setup_caps(sk, &rt->dst); | |
361 | } | |
362 | skb_dst_set_noref(skb, &rt->dst); | |
363 | ||
364 | packet_routed: | |
365 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) | |
366 | goto no_route; | |
367 | ||
368 | /* OK, we know where to send it, allocate and build IP header. */ | |
369 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); | |
370 | skb_reset_network_header(skb); | |
371 | iph = ip_hdr(skb); | |
372 | *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); | |
373 | if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df) | |
374 | iph->frag_off = htons(IP_DF); | |
375 | else | |
376 | iph->frag_off = 0; | |
377 | iph->ttl = ip_select_ttl(inet, &rt->dst); | |
378 | iph->protocol = sk->sk_protocol; | |
379 | iph->saddr = rt->rt_src; | |
380 | iph->daddr = rt->rt_dst; | |
381 | /* Transport layer set skb->h.foo itself. */ | |
382 | ||
383 | if (opt && opt->optlen) { | |
384 | iph->ihl += opt->optlen >> 2; | |
385 | ip_options_build(skb, opt, inet->inet_daddr, rt, 0); | |
386 | } | |
387 | ||
388 | ip_select_ident_more(iph, &rt->dst, sk, | |
389 | (skb_shinfo(skb)->gso_segs ?: 1) - 1); | |
390 | ||
391 | skb->priority = sk->sk_priority; | |
392 | skb->mark = sk->sk_mark; | |
393 | ||
394 | res = ip_local_out(skb); | |
395 | rcu_read_unlock(); | |
396 | return res; | |
397 | ||
398 | no_route: | |
399 | rcu_read_unlock(); | |
400 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); | |
401 | kfree_skb(skb); | |
402 | return -EHOSTUNREACH; | |
403 | } | |
404 | EXPORT_SYMBOL(ip_queue_xmit); | |
405 | ||
406 | ||
407 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
408 | { | |
409 | to->pkt_type = from->pkt_type; | |
410 | to->priority = from->priority; | |
411 | to->protocol = from->protocol; | |
412 | skb_dst_drop(to); | |
413 | skb_dst_copy(to, from); | |
414 | to->dev = from->dev; | |
415 | to->mark = from->mark; | |
416 | ||
417 | /* Copy the flags to each fragment. */ | |
418 | IPCB(to)->flags = IPCB(from)->flags; | |
419 | ||
420 | #ifdef CONFIG_NET_SCHED | |
421 | to->tc_index = from->tc_index; | |
422 | #endif | |
423 | nf_copy(to, from); | |
424 | #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ | |
425 | defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) | |
426 | to->nf_trace = from->nf_trace; | |
427 | #endif | |
428 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) | |
429 | to->ipvs_property = from->ipvs_property; | |
430 | #endif | |
431 | skb_copy_secmark(to, from); | |
432 | } | |
433 | ||
434 | /* | |
435 | * This IP datagram is too large to be sent in one piece. Break it up into | |
436 | * smaller pieces (each of size equal to IP header plus | |
437 | * a block of the data of the original IP data part) that will yet fit in a | |
438 | * single device frame, and queue such a frame for sending. | |
439 | */ | |
440 | ||
441 | int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) | |
442 | { | |
443 | struct iphdr *iph; | |
444 | int ptr; | |
445 | struct net_device *dev; | |
446 | struct sk_buff *skb2; | |
447 | unsigned int mtu, hlen, left, len, ll_rs; | |
448 | int offset; | |
449 | __be16 not_last_frag; | |
450 | struct rtable *rt = skb_rtable(skb); | |
451 | int err = 0; | |
452 | ||
453 | dev = rt->dst.dev; | |
454 | ||
455 | /* | |
456 | * Point into the IP datagram header. | |
457 | */ | |
458 | ||
459 | iph = ip_hdr(skb); | |
460 | ||
461 | if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) { | |
462 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
463 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, | |
464 | htonl(ip_skb_dst_mtu(skb))); | |
465 | kfree_skb(skb); | |
466 | return -EMSGSIZE; | |
467 | } | |
468 | ||
469 | /* | |
470 | * Setup starting values. | |
471 | */ | |
472 | ||
473 | hlen = iph->ihl * 4; | |
474 | mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */ | |
475 | #ifdef CONFIG_BRIDGE_NETFILTER | |
476 | if (skb->nf_bridge) | |
477 | mtu -= nf_bridge_mtu_reduction(skb); | |
478 | #endif | |
479 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; | |
480 | ||
481 | /* When frag_list is given, use it. First, check its validity: | |
482 | * some transformers could create wrong frag_list or break existing | |
483 | * one, it is not prohibited. In this case fall back to copying. | |
484 | * | |
485 | * LATER: this step can be merged to real generation of fragments, | |
486 | * we can switch to copy when see the first bad fragment. | |
487 | */ | |
488 | if (skb_has_frag_list(skb)) { | |
489 | struct sk_buff *frag, *frag2; | |
490 | int first_len = skb_pagelen(skb); | |
491 | ||
492 | if (first_len - hlen > mtu || | |
493 | ((first_len - hlen) & 7) || | |
494 | (iph->frag_off & htons(IP_MF|IP_OFFSET)) || | |
495 | skb_cloned(skb)) | |
496 | goto slow_path; | |
497 | ||
498 | skb_walk_frags(skb, frag) { | |
499 | /* Correct geometry. */ | |
500 | if (frag->len > mtu || | |
501 | ((frag->len & 7) && frag->next) || | |
502 | skb_headroom(frag) < hlen) | |
503 | goto slow_path_clean; | |
504 | ||
505 | /* Partially cloned skb? */ | |
506 | if (skb_shared(frag)) | |
507 | goto slow_path_clean; | |
508 | ||
509 | BUG_ON(frag->sk); | |
510 | if (skb->sk) { | |
511 | frag->sk = skb->sk; | |
512 | frag->destructor = sock_wfree; | |
513 | } | |
514 | skb->truesize -= frag->truesize; | |
515 | } | |
516 | ||
517 | /* Everything is OK. Generate! */ | |
518 | ||
519 | err = 0; | |
520 | offset = 0; | |
521 | frag = skb_shinfo(skb)->frag_list; | |
522 | skb_frag_list_init(skb); | |
523 | skb->data_len = first_len - skb_headlen(skb); | |
524 | skb->len = first_len; | |
525 | iph->tot_len = htons(first_len); | |
526 | iph->frag_off = htons(IP_MF); | |
527 | ip_send_check(iph); | |
528 | ||
529 | for (;;) { | |
530 | /* Prepare header of the next frame, | |
531 | * before previous one went down. */ | |
532 | if (frag) { | |
533 | frag->ip_summed = CHECKSUM_NONE; | |
534 | skb_reset_transport_header(frag); | |
535 | __skb_push(frag, hlen); | |
536 | skb_reset_network_header(frag); | |
537 | memcpy(skb_network_header(frag), iph, hlen); | |
538 | iph = ip_hdr(frag); | |
539 | iph->tot_len = htons(frag->len); | |
540 | ip_copy_metadata(frag, skb); | |
541 | if (offset == 0) | |
542 | ip_options_fragment(frag); | |
543 | offset += skb->len - hlen; | |
544 | iph->frag_off = htons(offset>>3); | |
545 | if (frag->next != NULL) | |
546 | iph->frag_off |= htons(IP_MF); | |
547 | /* Ready, complete checksum */ | |
548 | ip_send_check(iph); | |
549 | } | |
550 | ||
551 | err = output(skb); | |
552 | ||
553 | if (!err) | |
554 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); | |
555 | if (err || !frag) | |
556 | break; | |
557 | ||
558 | skb = frag; | |
559 | frag = skb->next; | |
560 | skb->next = NULL; | |
561 | } | |
562 | ||
563 | if (err == 0) { | |
564 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); | |
565 | return 0; | |
566 | } | |
567 | ||
568 | while (frag) { | |
569 | skb = frag->next; | |
570 | kfree_skb(frag); | |
571 | frag = skb; | |
572 | } | |
573 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
574 | return err; | |
575 | ||
576 | slow_path_clean: | |
577 | skb_walk_frags(skb, frag2) { | |
578 | if (frag2 == frag) | |
579 | break; | |
580 | frag2->sk = NULL; | |
581 | frag2->destructor = NULL; | |
582 | skb->truesize += frag2->truesize; | |
583 | } | |
584 | } | |
585 | ||
586 | slow_path: | |
587 | left = skb->len - hlen; /* Space per frame */ | |
588 | ptr = hlen; /* Where to start from */ | |
589 | ||
590 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, | |
591 | * we need to make room for the encapsulating header | |
592 | */ | |
593 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb)); | |
594 | ||
595 | /* | |
596 | * Fragment the datagram. | |
597 | */ | |
598 | ||
599 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
600 | not_last_frag = iph->frag_off & htons(IP_MF); | |
601 | ||
602 | /* | |
603 | * Keep copying data until we run out. | |
604 | */ | |
605 | ||
606 | while (left > 0) { | |
607 | len = left; | |
608 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
609 | if (len > mtu) | |
610 | len = mtu; | |
611 | /* IF: we are not sending upto and including the packet end | |
612 | then align the next start on an eight byte boundary */ | |
613 | if (len < left) { | |
614 | len &= ~7; | |
615 | } | |
616 | /* | |
617 | * Allocate buffer. | |
618 | */ | |
619 | ||
620 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { | |
621 | NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); | |
622 | err = -ENOMEM; | |
623 | goto fail; | |
624 | } | |
625 | ||
626 | /* | |
627 | * Set up data on packet | |
628 | */ | |
629 | ||
630 | ip_copy_metadata(skb2, skb); | |
631 | skb_reserve(skb2, ll_rs); | |
632 | skb_put(skb2, len + hlen); | |
633 | skb_reset_network_header(skb2); | |
634 | skb2->transport_header = skb2->network_header + hlen; | |
635 | ||
636 | /* | |
637 | * Charge the memory for the fragment to any owner | |
638 | * it might possess | |
639 | */ | |
640 | ||
641 | if (skb->sk) | |
642 | skb_set_owner_w(skb2, skb->sk); | |
643 | ||
644 | /* | |
645 | * Copy the packet header into the new buffer. | |
646 | */ | |
647 | ||
648 | skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); | |
649 | ||
650 | /* | |
651 | * Copy a block of the IP datagram. | |
652 | */ | |
653 | if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) | |
654 | BUG(); | |
655 | left -= len; | |
656 | ||
657 | /* | |
658 | * Fill in the new header fields. | |
659 | */ | |
660 | iph = ip_hdr(skb2); | |
661 | iph->frag_off = htons((offset >> 3)); | |
662 | ||
663 | /* ANK: dirty, but effective trick. Upgrade options only if | |
664 | * the segment to be fragmented was THE FIRST (otherwise, | |
665 | * options are already fixed) and make it ONCE | |
666 | * on the initial skb, so that all the following fragments | |
667 | * will inherit fixed options. | |
668 | */ | |
669 | if (offset == 0) | |
670 | ip_options_fragment(skb); | |
671 | ||
672 | /* | |
673 | * Added AC : If we are fragmenting a fragment that's not the | |
674 | * last fragment then keep MF on each bit | |
675 | */ | |
676 | if (left > 0 || not_last_frag) | |
677 | iph->frag_off |= htons(IP_MF); | |
678 | ptr += len; | |
679 | offset += len; | |
680 | ||
681 | /* | |
682 | * Put this fragment into the sending queue. | |
683 | */ | |
684 | iph->tot_len = htons(len + hlen); | |
685 | ||
686 | ip_send_check(iph); | |
687 | ||
688 | err = output(skb2); | |
689 | if (err) | |
690 | goto fail; | |
691 | ||
692 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); | |
693 | } | |
694 | kfree_skb(skb); | |
695 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); | |
696 | return err; | |
697 | ||
698 | fail: | |
699 | kfree_skb(skb); | |
700 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); | |
701 | return err; | |
702 | } | |
703 | EXPORT_SYMBOL(ip_fragment); | |
704 | ||
705 | int | |
706 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
707 | { | |
708 | struct iovec *iov = from; | |
709 | ||
710 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
711 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) | |
712 | return -EFAULT; | |
713 | } else { | |
714 | __wsum csum = 0; | |
715 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) | |
716 | return -EFAULT; | |
717 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
718 | } | |
719 | return 0; | |
720 | } | |
721 | EXPORT_SYMBOL(ip_generic_getfrag); | |
722 | ||
723 | static inline __wsum | |
724 | csum_page(struct page *page, int offset, int copy) | |
725 | { | |
726 | char *kaddr; | |
727 | __wsum csum; | |
728 | kaddr = kmap(page); | |
729 | csum = csum_partial(kaddr + offset, copy, 0); | |
730 | kunmap(page); | |
731 | return csum; | |
732 | } | |
733 | ||
734 | static inline int ip_ufo_append_data(struct sock *sk, | |
735 | int getfrag(void *from, char *to, int offset, int len, | |
736 | int odd, struct sk_buff *skb), | |
737 | void *from, int length, int hh_len, int fragheaderlen, | |
738 | int transhdrlen, int mtu, unsigned int flags) | |
739 | { | |
740 | struct sk_buff *skb; | |
741 | int err; | |
742 | ||
743 | /* There is support for UDP fragmentation offload by network | |
744 | * device, so create one single skb packet containing complete | |
745 | * udp datagram | |
746 | */ | |
747 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { | |
748 | skb = sock_alloc_send_skb(sk, | |
749 | hh_len + fragheaderlen + transhdrlen + 20, | |
750 | (flags & MSG_DONTWAIT), &err); | |
751 | ||
752 | if (skb == NULL) | |
753 | return err; | |
754 | ||
755 | /* reserve space for Hardware header */ | |
756 | skb_reserve(skb, hh_len); | |
757 | ||
758 | /* create space for UDP/IP header */ | |
759 | skb_put(skb, fragheaderlen + transhdrlen); | |
760 | ||
761 | /* initialize network header pointer */ | |
762 | skb_reset_network_header(skb); | |
763 | ||
764 | /* initialize protocol header pointer */ | |
765 | skb->transport_header = skb->network_header + fragheaderlen; | |
766 | ||
767 | skb->ip_summed = CHECKSUM_PARTIAL; | |
768 | skb->csum = 0; | |
769 | sk->sk_sndmsg_off = 0; | |
770 | ||
771 | /* specify the length of each IP datagram fragment */ | |
772 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; | |
773 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
774 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
775 | } | |
776 | ||
777 | return skb_append_datato_frags(sk, skb, getfrag, from, | |
778 | (length - transhdrlen)); | |
779 | } | |
780 | ||
781 | /* | |
782 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
783 | * from many pieces of data. Each pieces will be holded on the socket | |
784 | * until ip_push_pending_frames() is called. Each piece can be a page | |
785 | * or non-page data. | |
786 | * | |
787 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
788 | * this interface potentially. | |
789 | * | |
790 | * LATER: length must be adjusted by pad at tail, when it is required. | |
791 | */ | |
792 | int ip_append_data(struct sock *sk, | |
793 | int getfrag(void *from, char *to, int offset, int len, | |
794 | int odd, struct sk_buff *skb), | |
795 | void *from, int length, int transhdrlen, | |
796 | struct ipcm_cookie *ipc, struct rtable **rtp, | |
797 | unsigned int flags) | |
798 | { | |
799 | struct inet_sock *inet = inet_sk(sk); | |
800 | struct sk_buff *skb; | |
801 | ||
802 | struct ip_options *opt = NULL; | |
803 | int hh_len; | |
804 | int exthdrlen; | |
805 | int mtu; | |
806 | int copy; | |
807 | int err; | |
808 | int offset = 0; | |
809 | unsigned int maxfraglen, fragheaderlen; | |
810 | int csummode = CHECKSUM_NONE; | |
811 | struct rtable *rt; | |
812 | ||
813 | if (flags&MSG_PROBE) | |
814 | return 0; | |
815 | ||
816 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
817 | /* | |
818 | * setup for corking. | |
819 | */ | |
820 | opt = ipc->opt; | |
821 | if (opt) { | |
822 | if (inet->cork.opt == NULL) { | |
823 | inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation); | |
824 | if (unlikely(inet->cork.opt == NULL)) | |
825 | return -ENOBUFS; | |
826 | } | |
827 | memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen); | |
828 | inet->cork.flags |= IPCORK_OPT; | |
829 | inet->cork.addr = ipc->addr; | |
830 | } | |
831 | rt = *rtp; | |
832 | if (unlikely(!rt)) | |
833 | return -EFAULT; | |
834 | /* | |
835 | * We steal reference to this route, caller should not release it | |
836 | */ | |
837 | *rtp = NULL; | |
838 | inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ? | |
839 | rt->dst.dev->mtu : | |
840 | dst_mtu(rt->dst.path); | |
841 | inet->cork.dst = &rt->dst; | |
842 | inet->cork.length = 0; | |
843 | sk->sk_sndmsg_page = NULL; | |
844 | sk->sk_sndmsg_off = 0; | |
845 | exthdrlen = rt->dst.header_len; | |
846 | length += exthdrlen; | |
847 | transhdrlen += exthdrlen; | |
848 | } else { | |
849 | rt = (struct rtable *)inet->cork.dst; | |
850 | if (inet->cork.flags & IPCORK_OPT) | |
851 | opt = inet->cork.opt; | |
852 | ||
853 | transhdrlen = 0; | |
854 | exthdrlen = 0; | |
855 | mtu = inet->cork.fragsize; | |
856 | } | |
857 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); | |
858 | ||
859 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
860 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
861 | ||
862 | if (inet->cork.length + length > 0xFFFF - fragheaderlen) { | |
863 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport, | |
864 | mtu-exthdrlen); | |
865 | return -EMSGSIZE; | |
866 | } | |
867 | ||
868 | /* | |
869 | * transhdrlen > 0 means that this is the first fragment and we wish | |
870 | * it won't be fragmented in the future. | |
871 | */ | |
872 | if (transhdrlen && | |
873 | length + fragheaderlen <= mtu && | |
874 | rt->dst.dev->features & NETIF_F_V4_CSUM && | |
875 | !exthdrlen) | |
876 | csummode = CHECKSUM_PARTIAL; | |
877 | ||
878 | skb = skb_peek_tail(&sk->sk_write_queue); | |
879 | ||
880 | inet->cork.length += length; | |
881 | if (((length > mtu) || (skb && skb_is_gso(skb))) && | |
882 | (sk->sk_protocol == IPPROTO_UDP) && | |
883 | (rt->dst.dev->features & NETIF_F_UFO)) { | |
884 | err = ip_ufo_append_data(sk, getfrag, from, length, hh_len, | |
885 | fragheaderlen, transhdrlen, mtu, | |
886 | flags); | |
887 | if (err) | |
888 | goto error; | |
889 | return 0; | |
890 | } | |
891 | ||
892 | /* So, what's going on in the loop below? | |
893 | * | |
894 | * We use calculated fragment length to generate chained skb, | |
895 | * each of segments is IP fragment ready for sending to network after | |
896 | * adding appropriate IP header. | |
897 | */ | |
898 | ||
899 | if (!skb) | |
900 | goto alloc_new_skb; | |
901 | ||
902 | while (length > 0) { | |
903 | /* Check if the remaining data fits into current packet. */ | |
904 | copy = mtu - skb->len; | |
905 | if (copy < length) | |
906 | copy = maxfraglen - skb->len; | |
907 | if (copy <= 0) { | |
908 | char *data; | |
909 | unsigned int datalen; | |
910 | unsigned int fraglen; | |
911 | unsigned int fraggap; | |
912 | unsigned int alloclen; | |
913 | struct sk_buff *skb_prev; | |
914 | alloc_new_skb: | |
915 | skb_prev = skb; | |
916 | if (skb_prev) | |
917 | fraggap = skb_prev->len - maxfraglen; | |
918 | else | |
919 | fraggap = 0; | |
920 | ||
921 | /* | |
922 | * If remaining data exceeds the mtu, | |
923 | * we know we need more fragment(s). | |
924 | */ | |
925 | datalen = length + fraggap; | |
926 | if (datalen > mtu - fragheaderlen) | |
927 | datalen = maxfraglen - fragheaderlen; | |
928 | fraglen = datalen + fragheaderlen; | |
929 | ||
930 | if ((flags & MSG_MORE) && | |
931 | !(rt->dst.dev->features&NETIF_F_SG)) | |
932 | alloclen = mtu; | |
933 | else | |
934 | alloclen = fraglen; | |
935 | ||
936 | /* The last fragment gets additional space at tail. | |
937 | * Note, with MSG_MORE we overallocate on fragments, | |
938 | * because we have no idea what fragment will be | |
939 | * the last. | |
940 | */ | |
941 | if (datalen == length + fraggap) { | |
942 | alloclen += rt->dst.trailer_len; | |
943 | /* make sure mtu is not reached */ | |
944 | if (datalen > mtu - fragheaderlen - rt->dst.trailer_len) | |
945 | datalen -= ALIGN(rt->dst.trailer_len, 8); | |
946 | } | |
947 | if (transhdrlen) { | |
948 | skb = sock_alloc_send_skb(sk, | |
949 | alloclen + hh_len + 15, | |
950 | (flags & MSG_DONTWAIT), &err); | |
951 | } else { | |
952 | skb = NULL; | |
953 | if (atomic_read(&sk->sk_wmem_alloc) <= | |
954 | 2 * sk->sk_sndbuf) | |
955 | skb = sock_wmalloc(sk, | |
956 | alloclen + hh_len + 15, 1, | |
957 | sk->sk_allocation); | |
958 | if (unlikely(skb == NULL)) | |
959 | err = -ENOBUFS; | |
960 | else | |
961 | /* only the initial fragment is | |
962 | time stamped */ | |
963 | ipc->tx_flags = 0; | |
964 | } | |
965 | if (skb == NULL) | |
966 | goto error; | |
967 | ||
968 | /* | |
969 | * Fill in the control structures | |
970 | */ | |
971 | skb->ip_summed = csummode; | |
972 | skb->csum = 0; | |
973 | skb_reserve(skb, hh_len); | |
974 | skb_shinfo(skb)->tx_flags = ipc->tx_flags; | |
975 | ||
976 | /* | |
977 | * Find where to start putting bytes. | |
978 | */ | |
979 | data = skb_put(skb, fraglen); | |
980 | skb_set_network_header(skb, exthdrlen); | |
981 | skb->transport_header = (skb->network_header + | |
982 | fragheaderlen); | |
983 | data += fragheaderlen; | |
984 | ||
985 | if (fraggap) { | |
986 | skb->csum = skb_copy_and_csum_bits( | |
987 | skb_prev, maxfraglen, | |
988 | data + transhdrlen, fraggap, 0); | |
989 | skb_prev->csum = csum_sub(skb_prev->csum, | |
990 | skb->csum); | |
991 | data += fraggap; | |
992 | pskb_trim_unique(skb_prev, maxfraglen); | |
993 | } | |
994 | ||
995 | copy = datalen - transhdrlen - fraggap; | |
996 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
997 | err = -EFAULT; | |
998 | kfree_skb(skb); | |
999 | goto error; | |
1000 | } | |
1001 | ||
1002 | offset += copy; | |
1003 | length -= datalen - fraggap; | |
1004 | transhdrlen = 0; | |
1005 | exthdrlen = 0; | |
1006 | csummode = CHECKSUM_NONE; | |
1007 | ||
1008 | /* | |
1009 | * Put the packet on the pending queue. | |
1010 | */ | |
1011 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1012 | continue; | |
1013 | } | |
1014 | ||
1015 | if (copy > length) | |
1016 | copy = length; | |
1017 | ||
1018 | if (!(rt->dst.dev->features&NETIF_F_SG)) { | |
1019 | unsigned int off; | |
1020 | ||
1021 | off = skb->len; | |
1022 | if (getfrag(from, skb_put(skb, copy), | |
1023 | offset, copy, off, skb) < 0) { | |
1024 | __skb_trim(skb, off); | |
1025 | err = -EFAULT; | |
1026 | goto error; | |
1027 | } | |
1028 | } else { | |
1029 | int i = skb_shinfo(skb)->nr_frags; | |
1030 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; | |
1031 | struct page *page = sk->sk_sndmsg_page; | |
1032 | int off = sk->sk_sndmsg_off; | |
1033 | unsigned int left; | |
1034 | ||
1035 | if (page && (left = PAGE_SIZE - off) > 0) { | |
1036 | if (copy >= left) | |
1037 | copy = left; | |
1038 | if (page != frag->page) { | |
1039 | if (i == MAX_SKB_FRAGS) { | |
1040 | err = -EMSGSIZE; | |
1041 | goto error; | |
1042 | } | |
1043 | get_page(page); | |
1044 | skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); | |
1045 | frag = &skb_shinfo(skb)->frags[i]; | |
1046 | } | |
1047 | } else if (i < MAX_SKB_FRAGS) { | |
1048 | if (copy > PAGE_SIZE) | |
1049 | copy = PAGE_SIZE; | |
1050 | page = alloc_pages(sk->sk_allocation, 0); | |
1051 | if (page == NULL) { | |
1052 | err = -ENOMEM; | |
1053 | goto error; | |
1054 | } | |
1055 | sk->sk_sndmsg_page = page; | |
1056 | sk->sk_sndmsg_off = 0; | |
1057 | ||
1058 | skb_fill_page_desc(skb, i, page, 0, 0); | |
1059 | frag = &skb_shinfo(skb)->frags[i]; | |
1060 | } else { | |
1061 | err = -EMSGSIZE; | |
1062 | goto error; | |
1063 | } | |
1064 | if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { | |
1065 | err = -EFAULT; | |
1066 | goto error; | |
1067 | } | |
1068 | sk->sk_sndmsg_off += copy; | |
1069 | frag->size += copy; | |
1070 | skb->len += copy; | |
1071 | skb->data_len += copy; | |
1072 | skb->truesize += copy; | |
1073 | atomic_add(copy, &sk->sk_wmem_alloc); | |
1074 | } | |
1075 | offset += copy; | |
1076 | length -= copy; | |
1077 | } | |
1078 | ||
1079 | return 0; | |
1080 | ||
1081 | error: | |
1082 | inet->cork.length -= length; | |
1083 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1084 | return err; | |
1085 | } | |
1086 | ||
1087 | ssize_t ip_append_page(struct sock *sk, struct page *page, | |
1088 | int offset, size_t size, int flags) | |
1089 | { | |
1090 | struct inet_sock *inet = inet_sk(sk); | |
1091 | struct sk_buff *skb; | |
1092 | struct rtable *rt; | |
1093 | struct ip_options *opt = NULL; | |
1094 | int hh_len; | |
1095 | int mtu; | |
1096 | int len; | |
1097 | int err; | |
1098 | unsigned int maxfraglen, fragheaderlen, fraggap; | |
1099 | ||
1100 | if (inet->hdrincl) | |
1101 | return -EPERM; | |
1102 | ||
1103 | if (flags&MSG_PROBE) | |
1104 | return 0; | |
1105 | ||
1106 | if (skb_queue_empty(&sk->sk_write_queue)) | |
1107 | return -EINVAL; | |
1108 | ||
1109 | rt = (struct rtable *)inet->cork.dst; | |
1110 | if (inet->cork.flags & IPCORK_OPT) | |
1111 | opt = inet->cork.opt; | |
1112 | ||
1113 | if (!(rt->dst.dev->features&NETIF_F_SG)) | |
1114 | return -EOPNOTSUPP; | |
1115 | ||
1116 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); | |
1117 | mtu = inet->cork.fragsize; | |
1118 | ||
1119 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1120 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1121 | ||
1122 | if (inet->cork.length + size > 0xFFFF - fragheaderlen) { | |
1123 | ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport, mtu); | |
1124 | return -EMSGSIZE; | |
1125 | } | |
1126 | ||
1127 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
1128 | return -EINVAL; | |
1129 | ||
1130 | inet->cork.length += size; | |
1131 | if ((size + skb->len > mtu) && | |
1132 | (sk->sk_protocol == IPPROTO_UDP) && | |
1133 | (rt->dst.dev->features & NETIF_F_UFO)) { | |
1134 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; | |
1135 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
1136 | } | |
1137 | ||
1138 | ||
1139 | while (size > 0) { | |
1140 | int i; | |
1141 | ||
1142 | if (skb_is_gso(skb)) | |
1143 | len = size; | |
1144 | else { | |
1145 | ||
1146 | /* Check if the remaining data fits into current packet. */ | |
1147 | len = mtu - skb->len; | |
1148 | if (len < size) | |
1149 | len = maxfraglen - skb->len; | |
1150 | } | |
1151 | if (len <= 0) { | |
1152 | struct sk_buff *skb_prev; | |
1153 | int alloclen; | |
1154 | ||
1155 | skb_prev = skb; | |
1156 | fraggap = skb_prev->len - maxfraglen; | |
1157 | ||
1158 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1159 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1160 | if (unlikely(!skb)) { | |
1161 | err = -ENOBUFS; | |
1162 | goto error; | |
1163 | } | |
1164 | ||
1165 | /* | |
1166 | * Fill in the control structures | |
1167 | */ | |
1168 | skb->ip_summed = CHECKSUM_NONE; | |
1169 | skb->csum = 0; | |
1170 | skb_reserve(skb, hh_len); | |
1171 | ||
1172 | /* | |
1173 | * Find where to start putting bytes. | |
1174 | */ | |
1175 | skb_put(skb, fragheaderlen + fraggap); | |
1176 | skb_reset_network_header(skb); | |
1177 | skb->transport_header = (skb->network_header + | |
1178 | fragheaderlen); | |
1179 | if (fraggap) { | |
1180 | skb->csum = skb_copy_and_csum_bits(skb_prev, | |
1181 | maxfraglen, | |
1182 | skb_transport_header(skb), | |
1183 | fraggap, 0); | |
1184 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1185 | skb->csum); | |
1186 | pskb_trim_unique(skb_prev, maxfraglen); | |
1187 | } | |
1188 | ||
1189 | /* | |
1190 | * Put the packet on the pending queue. | |
1191 | */ | |
1192 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1193 | continue; | |
1194 | } | |
1195 | ||
1196 | i = skb_shinfo(skb)->nr_frags; | |
1197 | if (len > size) | |
1198 | len = size; | |
1199 | if (skb_can_coalesce(skb, i, page, offset)) { | |
1200 | skb_shinfo(skb)->frags[i-1].size += len; | |
1201 | } else if (i < MAX_SKB_FRAGS) { | |
1202 | get_page(page); | |
1203 | skb_fill_page_desc(skb, i, page, offset, len); | |
1204 | } else { | |
1205 | err = -EMSGSIZE; | |
1206 | goto error; | |
1207 | } | |
1208 | ||
1209 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1210 | __wsum csum; | |
1211 | csum = csum_page(page, offset, len); | |
1212 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1213 | } | |
1214 | ||
1215 | skb->len += len; | |
1216 | skb->data_len += len; | |
1217 | skb->truesize += len; | |
1218 | atomic_add(len, &sk->sk_wmem_alloc); | |
1219 | offset += len; | |
1220 | size -= len; | |
1221 | } | |
1222 | return 0; | |
1223 | ||
1224 | error: | |
1225 | inet->cork.length -= size; | |
1226 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1227 | return err; | |
1228 | } | |
1229 | ||
1230 | static void ip_cork_release(struct inet_sock *inet) | |
1231 | { | |
1232 | inet->cork.flags &= ~IPCORK_OPT; | |
1233 | kfree(inet->cork.opt); | |
1234 | inet->cork.opt = NULL; | |
1235 | dst_release(inet->cork.dst); | |
1236 | inet->cork.dst = NULL; | |
1237 | } | |
1238 | ||
1239 | /* | |
1240 | * Combined all pending IP fragments on the socket as one IP datagram | |
1241 | * and push them out. | |
1242 | */ | |
1243 | int ip_push_pending_frames(struct sock *sk) | |
1244 | { | |
1245 | struct sk_buff *skb, *tmp_skb; | |
1246 | struct sk_buff **tail_skb; | |
1247 | struct inet_sock *inet = inet_sk(sk); | |
1248 | struct net *net = sock_net(sk); | |
1249 | struct ip_options *opt = NULL; | |
1250 | struct rtable *rt = (struct rtable *)inet->cork.dst; | |
1251 | struct iphdr *iph; | |
1252 | __be16 df = 0; | |
1253 | __u8 ttl; | |
1254 | int err = 0; | |
1255 | ||
1256 | if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) | |
1257 | goto out; | |
1258 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1259 | ||
1260 | /* move skb->data to ip header from ext header */ | |
1261 | if (skb->data < skb_network_header(skb)) | |
1262 | __skb_pull(skb, skb_network_offset(skb)); | |
1263 | while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { | |
1264 | __skb_pull(tmp_skb, skb_network_header_len(skb)); | |
1265 | *tail_skb = tmp_skb; | |
1266 | tail_skb = &(tmp_skb->next); | |
1267 | skb->len += tmp_skb->len; | |
1268 | skb->data_len += tmp_skb->len; | |
1269 | skb->truesize += tmp_skb->truesize; | |
1270 | tmp_skb->destructor = NULL; | |
1271 | tmp_skb->sk = NULL; | |
1272 | } | |
1273 | ||
1274 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1275 | * to fragment the frame generated here. No matter, what transforms | |
1276 | * how transforms change size of the packet, it will come out. | |
1277 | */ | |
1278 | if (inet->pmtudisc < IP_PMTUDISC_DO) | |
1279 | skb->local_df = 1; | |
1280 | ||
1281 | /* DF bit is set when we want to see DF on outgoing frames. | |
1282 | * If local_df is set too, we still allow to fragment this frame | |
1283 | * locally. */ | |
1284 | if (inet->pmtudisc >= IP_PMTUDISC_DO || | |
1285 | (skb->len <= dst_mtu(&rt->dst) && | |
1286 | ip_dont_fragment(sk, &rt->dst))) | |
1287 | df = htons(IP_DF); | |
1288 | ||
1289 | if (inet->cork.flags & IPCORK_OPT) | |
1290 | opt = inet->cork.opt; | |
1291 | ||
1292 | if (rt->rt_type == RTN_MULTICAST) | |
1293 | ttl = inet->mc_ttl; | |
1294 | else | |
1295 | ttl = ip_select_ttl(inet, &rt->dst); | |
1296 | ||
1297 | iph = (struct iphdr *)skb->data; | |
1298 | iph->version = 4; | |
1299 | iph->ihl = 5; | |
1300 | if (opt) { | |
1301 | iph->ihl += opt->optlen>>2; | |
1302 | ip_options_build(skb, opt, inet->cork.addr, rt, 0); | |
1303 | } | |
1304 | iph->tos = inet->tos; | |
1305 | iph->frag_off = df; | |
1306 | ip_select_ident(iph, &rt->dst, sk); | |
1307 | iph->ttl = ttl; | |
1308 | iph->protocol = sk->sk_protocol; | |
1309 | iph->saddr = rt->rt_src; | |
1310 | iph->daddr = rt->rt_dst; | |
1311 | ||
1312 | skb->priority = sk->sk_priority; | |
1313 | skb->mark = sk->sk_mark; | |
1314 | /* | |
1315 | * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec | |
1316 | * on dst refcount | |
1317 | */ | |
1318 | inet->cork.dst = NULL; | |
1319 | skb_dst_set(skb, &rt->dst); | |
1320 | ||
1321 | if (iph->protocol == IPPROTO_ICMP) | |
1322 | icmp_out_count(net, ((struct icmphdr *) | |
1323 | skb_transport_header(skb))->type); | |
1324 | ||
1325 | /* Netfilter gets whole the not fragmented skb. */ | |
1326 | err = ip_local_out(skb); | |
1327 | if (err) { | |
1328 | if (err > 0) | |
1329 | err = net_xmit_errno(err); | |
1330 | if (err) | |
1331 | goto error; | |
1332 | } | |
1333 | ||
1334 | out: | |
1335 | ip_cork_release(inet); | |
1336 | return err; | |
1337 | ||
1338 | error: | |
1339 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); | |
1340 | goto out; | |
1341 | } | |
1342 | ||
1343 | /* | |
1344 | * Throw away all pending data on the socket. | |
1345 | */ | |
1346 | void ip_flush_pending_frames(struct sock *sk) | |
1347 | { | |
1348 | struct sk_buff *skb; | |
1349 | ||
1350 | while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) | |
1351 | kfree_skb(skb); | |
1352 | ||
1353 | ip_cork_release(inet_sk(sk)); | |
1354 | } | |
1355 | ||
1356 | ||
1357 | /* | |
1358 | * Fetch data from kernel space and fill in checksum if needed. | |
1359 | */ | |
1360 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, | |
1361 | int len, int odd, struct sk_buff *skb) | |
1362 | { | |
1363 | __wsum csum; | |
1364 | ||
1365 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); | |
1366 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
1367 | return 0; | |
1368 | } | |
1369 | ||
1370 | /* | |
1371 | * Generic function to send a packet as reply to another packet. | |
1372 | * Used to send TCP resets so far. ICMP should use this function too. | |
1373 | * | |
1374 | * Should run single threaded per socket because it uses the sock | |
1375 | * structure to pass arguments. | |
1376 | */ | |
1377 | void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, | |
1378 | unsigned int len) | |
1379 | { | |
1380 | struct inet_sock *inet = inet_sk(sk); | |
1381 | struct { | |
1382 | struct ip_options opt; | |
1383 | char data[40]; | |
1384 | } replyopts; | |
1385 | struct ipcm_cookie ipc; | |
1386 | __be32 daddr; | |
1387 | struct rtable *rt = skb_rtable(skb); | |
1388 | ||
1389 | if (ip_options_echo(&replyopts.opt, skb)) | |
1390 | return; | |
1391 | ||
1392 | daddr = ipc.addr = rt->rt_src; | |
1393 | ipc.opt = NULL; | |
1394 | ipc.tx_flags = 0; | |
1395 | ||
1396 | if (replyopts.opt.optlen) { | |
1397 | ipc.opt = &replyopts.opt; | |
1398 | ||
1399 | if (ipc.opt->srr) | |
1400 | daddr = replyopts.opt.faddr; | |
1401 | } | |
1402 | ||
1403 | { | |
1404 | struct flowi fl = { .oif = arg->bound_dev_if, | |
1405 | .fl4_dst = daddr, | |
1406 | .fl4_src = rt->rt_spec_dst, | |
1407 | .fl4_tos = RT_TOS(ip_hdr(skb)->tos), | |
1408 | .fl_ip_sport = tcp_hdr(skb)->dest, | |
1409 | .fl_ip_dport = tcp_hdr(skb)->source, | |
1410 | .proto = sk->sk_protocol, | |
1411 | .flags = ip_reply_arg_flowi_flags(arg) }; | |
1412 | security_skb_classify_flow(skb, &fl); | |
1413 | if (ip_route_output_key(sock_net(sk), &rt, &fl)) | |
1414 | return; | |
1415 | } | |
1416 | ||
1417 | /* And let IP do all the hard work. | |
1418 | ||
1419 | This chunk is not reenterable, hence spinlock. | |
1420 | Note that it uses the fact, that this function is called | |
1421 | with locally disabled BH and that sk cannot be already spinlocked. | |
1422 | */ | |
1423 | bh_lock_sock(sk); | |
1424 | inet->tos = ip_hdr(skb)->tos; | |
1425 | sk->sk_priority = skb->priority; | |
1426 | sk->sk_protocol = ip_hdr(skb)->protocol; | |
1427 | sk->sk_bound_dev_if = arg->bound_dev_if; | |
1428 | ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0, | |
1429 | &ipc, &rt, MSG_DONTWAIT); | |
1430 | if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { | |
1431 | if (arg->csumoffset >= 0) | |
1432 | *((__sum16 *)skb_transport_header(skb) + | |
1433 | arg->csumoffset) = csum_fold(csum_add(skb->csum, | |
1434 | arg->csum)); | |
1435 | skb->ip_summed = CHECKSUM_NONE; | |
1436 | ip_push_pending_frames(sk); | |
1437 | } | |
1438 | ||
1439 | bh_unlock_sock(sk); | |
1440 | ||
1441 | ip_rt_put(rt); | |
1442 | } | |
1443 | ||
1444 | void __init ip_init(void) | |
1445 | { | |
1446 | ip_rt_init(); | |
1447 | inet_initpeers(); | |
1448 | ||
1449 | #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS) | |
1450 | igmp_mc_proc_init(); | |
1451 | #endif | |
1452 | } |