Commit | Line | Data |
---|---|---|
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 | * | |
02c30a84 | 8 | * Authors: Ross Biro |
1da177e4 LT |
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. | |
e905a9ed | 23 | * Bradford Johnson: Fix faulty handling of some frames when |
1da177e4 LT |
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. | |
e905a9ed YH |
34 | * Andi Kleen : Split fast and slow ip_build_xmit path |
35 | * for decreased register pressure on x86 | |
36 | * and more readibility. | |
1da177e4 LT |
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> | |
1da177e4 LT |
46 | #include <linux/module.h> |
47 | #include <linux/types.h> | |
48 | #include <linux/kernel.h> | |
1da177e4 LT |
49 | #include <linux/mm.h> |
50 | #include <linux/string.h> | |
51 | #include <linux/errno.h> | |
a1f8e7f7 | 52 | #include <linux/highmem.h> |
5a0e3ad6 | 53 | #include <linux/slab.h> |
1da177e4 LT |
54 | |
55 | #include <linux/socket.h> | |
56 | #include <linux/sockios.h> | |
57 | #include <linux/in.h> | |
58 | #include <linux/inet.h> | |
59 | #include <linux/netdevice.h> | |
60 | #include <linux/etherdevice.h> | |
61 | #include <linux/proc_fs.h> | |
62 | #include <linux/stat.h> | |
63 | #include <linux/init.h> | |
64 | ||
65 | #include <net/snmp.h> | |
66 | #include <net/ip.h> | |
67 | #include <net/protocol.h> | |
68 | #include <net/route.h> | |
cfacb057 | 69 | #include <net/xfrm.h> |
1da177e4 LT |
70 | #include <linux/skbuff.h> |
71 | #include <net/sock.h> | |
72 | #include <net/arp.h> | |
73 | #include <net/icmp.h> | |
1da177e4 LT |
74 | #include <net/checksum.h> |
75 | #include <net/inetpeer.h> | |
1da177e4 LT |
76 | #include <linux/igmp.h> |
77 | #include <linux/netfilter_ipv4.h> | |
78 | #include <linux/netfilter_bridge.h> | |
79 | #include <linux/mroute.h> | |
80 | #include <linux/netlink.h> | |
6cbb0df7 | 81 | #include <linux/tcp.h> |
1da177e4 | 82 | |
ab32ea5d | 83 | int sysctl_ip_default_ttl __read_mostly = IPDEFTTL; |
323e126f | 84 | EXPORT_SYMBOL(sysctl_ip_default_ttl); |
1da177e4 LT |
85 | |
86 | /* Generate a checksum for an outgoing IP datagram. */ | |
2fbd9679 | 87 | void ip_send_check(struct iphdr *iph) |
1da177e4 LT |
88 | { |
89 | iph->check = 0; | |
90 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
91 | } | |
4bc2f18b | 92 | EXPORT_SYMBOL(ip_send_check); |
1da177e4 | 93 | |
c439cb2e HX |
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); | |
9bbc768a JE |
100 | return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, skb, NULL, |
101 | skb_dst(skb)->dev, dst_output); | |
c439cb2e HX |
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 | ||
1da177e4 LT |
116 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) |
117 | { | |
118 | int ttl = inet->uc_ttl; | |
119 | ||
120 | if (ttl < 0) | |
323e126f | 121 | ttl = ip4_dst_hoplimit(dst); |
1da177e4 LT |
122 | return ttl; |
123 | } | |
124 | ||
e905a9ed | 125 | /* |
1da177e4 LT |
126 | * Add an ip header to a skbuff and send it out. |
127 | * | |
128 | */ | |
129 | int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, | |
f6d8bd05 | 130 | __be32 saddr, __be32 daddr, struct ip_options_rcu *opt) |
1da177e4 LT |
131 | { |
132 | struct inet_sock *inet = inet_sk(sk); | |
511c3f92 | 133 | struct rtable *rt = skb_rtable(skb); |
1da177e4 LT |
134 | struct iphdr *iph; |
135 | ||
136 | /* Build the IP header. */ | |
f6d8bd05 | 137 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); |
8856dfa3 | 138 | skb_reset_network_header(skb); |
eddc9ec5 | 139 | iph = ip_hdr(skb); |
1da177e4 LT |
140 | iph->version = 4; |
141 | iph->ihl = 5; | |
142 | iph->tos = inet->tos; | |
d8d1f30b | 143 | if (ip_dont_fragment(sk, &rt->dst)) |
1da177e4 LT |
144 | iph->frag_off = htons(IP_DF); |
145 | else | |
146 | iph->frag_off = 0; | |
d8d1f30b | 147 | iph->ttl = ip_select_ttl(inet, &rt->dst); |
dd927a26 DM |
148 | iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr); |
149 | iph->saddr = saddr; | |
1da177e4 | 150 | iph->protocol = sk->sk_protocol; |
703133de | 151 | ip_select_ident(skb, &rt->dst, sk); |
1da177e4 | 152 | |
f6d8bd05 ED |
153 | if (opt && opt->opt.optlen) { |
154 | iph->ihl += opt->opt.optlen>>2; | |
155 | ip_options_build(skb, &opt->opt, daddr, rt, 0); | |
1da177e4 | 156 | } |
1da177e4 LT |
157 | |
158 | skb->priority = sk->sk_priority; | |
4a19ec58 | 159 | skb->mark = sk->sk_mark; |
1da177e4 LT |
160 | |
161 | /* Send it out. */ | |
c439cb2e | 162 | return ip_local_out(skb); |
1da177e4 | 163 | } |
d8c97a94 ACM |
164 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); |
165 | ||
1da177e4 LT |
166 | static inline int ip_finish_output2(struct sk_buff *skb) |
167 | { | |
adf30907 | 168 | struct dst_entry *dst = skb_dst(skb); |
80787ebc | 169 | struct rtable *rt = (struct rtable *)dst; |
1da177e4 | 170 | struct net_device *dev = dst->dev; |
c2636b4d | 171 | unsigned int hh_len = LL_RESERVED_SPACE(dev); |
f6b72b62 | 172 | struct neighbour *neigh; |
a263b309 | 173 | u32 nexthop; |
1da177e4 | 174 | |
edf391ff NH |
175 | if (rt->rt_type == RTN_MULTICAST) { |
176 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len); | |
177 | } else if (rt->rt_type == RTN_BROADCAST) | |
178 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len); | |
80787ebc | 179 | |
1da177e4 | 180 | /* Be paranoid, rather than too clever. */ |
3b04ddde | 181 | if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { |
1da177e4 LT |
182 | struct sk_buff *skb2; |
183 | ||
184 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
185 | if (skb2 == NULL) { | |
186 | kfree_skb(skb); | |
187 | return -ENOMEM; | |
188 | } | |
189 | if (skb->sk) | |
190 | skb_set_owner_w(skb2, skb->sk); | |
5d0ba55b | 191 | consume_skb(skb); |
1da177e4 LT |
192 | skb = skb2; |
193 | } | |
194 | ||
a263b309 | 195 | rcu_read_lock_bh(); |
155e8336 | 196 | nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr); |
a263b309 DM |
197 | neigh = __ipv4_neigh_lookup_noref(dev, nexthop); |
198 | if (unlikely(!neigh)) | |
199 | neigh = __neigh_create(&arp_tbl, &nexthop, dev, false); | |
9871f1ad | 200 | if (!IS_ERR(neigh)) { |
5110effe | 201 | int res = dst_neigh_output(dst, neigh, skb); |
f2c31e32 | 202 | |
a263b309 | 203 | rcu_read_unlock_bh(); |
f2c31e32 ED |
204 | return res; |
205 | } | |
a263b309 | 206 | rcu_read_unlock_bh(); |
05e3aa09 | 207 | |
e87cc472 JP |
208 | net_dbg_ratelimited("%s: No header cache and no neighbour!\n", |
209 | __func__); | |
1da177e4 LT |
210 | kfree_skb(skb); |
211 | return -EINVAL; | |
212 | } | |
213 | ||
861d0486 | 214 | static int ip_finish_output(struct sk_buff *skb) |
1da177e4 | 215 | { |
5c901daa PM |
216 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) |
217 | /* Policy lookup after SNAT yielded a new policy */ | |
adf30907 | 218 | if (skb_dst(skb)->xfrm != NULL) { |
48d5cad8 PM |
219 | IPCB(skb)->flags |= IPSKB_REROUTED; |
220 | return dst_output(skb); | |
221 | } | |
5c901daa | 222 | #endif |
628a5c56 | 223 | if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb)) |
1bd9bef6 PM |
224 | return ip_fragment(skb, ip_finish_output2); |
225 | else | |
226 | return ip_finish_output2(skb); | |
1da177e4 LT |
227 | } |
228 | ||
229 | int ip_mc_output(struct sk_buff *skb) | |
230 | { | |
231 | struct sock *sk = skb->sk; | |
511c3f92 | 232 | struct rtable *rt = skb_rtable(skb); |
d8d1f30b | 233 | struct net_device *dev = rt->dst.dev; |
1da177e4 LT |
234 | |
235 | /* | |
236 | * If the indicated interface is up and running, send the packet. | |
237 | */ | |
edf391ff | 238 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); |
1da177e4 LT |
239 | |
240 | skb->dev = dev; | |
241 | skb->protocol = htons(ETH_P_IP); | |
242 | ||
243 | /* | |
244 | * Multicasts are looped back for other local users | |
245 | */ | |
246 | ||
247 | if (rt->rt_flags&RTCF_MULTICAST) { | |
7ad6848c | 248 | if (sk_mc_loop(sk) |
1da177e4 LT |
249 | #ifdef CONFIG_IP_MROUTE |
250 | /* Small optimization: do not loopback not local frames, | |
251 | which returned after forwarding; they will be dropped | |
252 | by ip_mr_input in any case. | |
253 | Note, that local frames are looped back to be delivered | |
254 | to local recipients. | |
255 | ||
256 | This check is duplicated in ip_mr_input at the moment. | |
257 | */ | |
9d4fb27d JP |
258 | && |
259 | ((rt->rt_flags & RTCF_LOCAL) || | |
260 | !(IPCB(skb)->flags & IPSKB_FORWARDED)) | |
1da177e4 | 261 | #endif |
9d4fb27d | 262 | ) { |
1da177e4 LT |
263 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
264 | if (newskb) | |
9bbc768a JE |
265 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
266 | newskb, NULL, newskb->dev, | |
95603e22 | 267 | dev_loopback_xmit); |
1da177e4 LT |
268 | } |
269 | ||
270 | /* Multicasts with ttl 0 must not go beyond the host */ | |
271 | ||
eddc9ec5 | 272 | if (ip_hdr(skb)->ttl == 0) { |
1da177e4 LT |
273 | kfree_skb(skb); |
274 | return 0; | |
275 | } | |
276 | } | |
277 | ||
278 | if (rt->rt_flags&RTCF_BROADCAST) { | |
279 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
280 | if (newskb) | |
9bbc768a | 281 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb, |
95603e22 | 282 | NULL, newskb->dev, dev_loopback_xmit); |
1da177e4 LT |
283 | } |
284 | ||
9bbc768a JE |
285 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, |
286 | skb->dev, ip_finish_output, | |
48d5cad8 | 287 | !(IPCB(skb)->flags & IPSKB_REROUTED)); |
1da177e4 LT |
288 | } |
289 | ||
290 | int ip_output(struct sk_buff *skb) | |
291 | { | |
adf30907 | 292 | struct net_device *dev = skb_dst(skb)->dev; |
1bd9bef6 | 293 | |
edf391ff | 294 | IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); |
1da177e4 | 295 | |
1bd9bef6 PM |
296 | skb->dev = dev; |
297 | skb->protocol = htons(ETH_P_IP); | |
298 | ||
9bbc768a | 299 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev, |
e905a9ed | 300 | ip_finish_output, |
48d5cad8 | 301 | !(IPCB(skb)->flags & IPSKB_REROUTED)); |
1da177e4 LT |
302 | } |
303 | ||
84f9307c ED |
304 | /* |
305 | * copy saddr and daddr, possibly using 64bit load/stores | |
306 | * Equivalent to : | |
307 | * iph->saddr = fl4->saddr; | |
308 | * iph->daddr = fl4->daddr; | |
309 | */ | |
310 | static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4) | |
311 | { | |
312 | BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) != | |
313 | offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr)); | |
314 | memcpy(&iph->saddr, &fl4->saddr, | |
315 | sizeof(fl4->saddr) + sizeof(fl4->daddr)); | |
316 | } | |
317 | ||
b0270e91 ED |
318 | /* Note: skb->sk can be different from sk, in case of tunnels */ |
319 | int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl) | |
1da177e4 | 320 | { |
1da177e4 | 321 | struct inet_sock *inet = inet_sk(sk); |
f6d8bd05 | 322 | struct ip_options_rcu *inet_opt; |
b57ae01a | 323 | struct flowi4 *fl4; |
1da177e4 LT |
324 | struct rtable *rt; |
325 | struct iphdr *iph; | |
ab6e3feb | 326 | int res; |
1da177e4 LT |
327 | |
328 | /* Skip all of this if the packet is already routed, | |
329 | * f.e. by something like SCTP. | |
330 | */ | |
ab6e3feb | 331 | rcu_read_lock(); |
f6d8bd05 | 332 | inet_opt = rcu_dereference(inet->inet_opt); |
ea4fc0d6 | 333 | fl4 = &fl->u.ip4; |
511c3f92 | 334 | rt = skb_rtable(skb); |
1da177e4 LT |
335 | if (rt != NULL) |
336 | goto packet_routed; | |
337 | ||
338 | /* Make sure we can route this packet. */ | |
339 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
340 | if (rt == NULL) { | |
3ca3c68e | 341 | __be32 daddr; |
1da177e4 LT |
342 | |
343 | /* Use correct destination address if we have options. */ | |
c720c7e8 | 344 | daddr = inet->inet_daddr; |
f6d8bd05 ED |
345 | if (inet_opt && inet_opt->opt.srr) |
346 | daddr = inet_opt->opt.faddr; | |
1da177e4 | 347 | |
78fbfd8a DM |
348 | /* If this fails, retransmit mechanism of transport layer will |
349 | * keep trying until route appears or the connection times | |
350 | * itself out. | |
351 | */ | |
b57ae01a | 352 | rt = ip_route_output_ports(sock_net(sk), fl4, sk, |
78fbfd8a DM |
353 | daddr, inet->inet_saddr, |
354 | inet->inet_dport, | |
355 | inet->inet_sport, | |
356 | sk->sk_protocol, | |
357 | RT_CONN_FLAGS(sk), | |
358 | sk->sk_bound_dev_if); | |
359 | if (IS_ERR(rt)) | |
360 | goto no_route; | |
d8d1f30b | 361 | sk_setup_caps(sk, &rt->dst); |
1da177e4 | 362 | } |
d8d1f30b | 363 | skb_dst_set_noref(skb, &rt->dst); |
1da177e4 LT |
364 | |
365 | packet_routed: | |
155e8336 | 366 | if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway) |
1da177e4 LT |
367 | goto no_route; |
368 | ||
369 | /* OK, we know where to send it, allocate and build IP header. */ | |
f6d8bd05 | 370 | skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0)); |
8856dfa3 | 371 | skb_reset_network_header(skb); |
eddc9ec5 | 372 | iph = ip_hdr(skb); |
714e85be | 373 | *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); |
d8d1f30b | 374 | if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df) |
1da177e4 LT |
375 | iph->frag_off = htons(IP_DF); |
376 | else | |
377 | iph->frag_off = 0; | |
d8d1f30b | 378 | iph->ttl = ip_select_ttl(inet, &rt->dst); |
1da177e4 | 379 | iph->protocol = sk->sk_protocol; |
84f9307c ED |
380 | ip_copy_addrs(iph, fl4); |
381 | ||
1da177e4 LT |
382 | /* Transport layer set skb->h.foo itself. */ |
383 | ||
f6d8bd05 ED |
384 | if (inet_opt && inet_opt->opt.optlen) { |
385 | iph->ihl += inet_opt->opt.optlen >> 2; | |
386 | ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0); | |
1da177e4 LT |
387 | } |
388 | ||
703133de | 389 | ip_select_ident_more(skb, &rt->dst, sk, |
7967168c | 390 | (skb_shinfo(skb)->gso_segs ?: 1) - 1); |
1da177e4 | 391 | |
b0270e91 | 392 | /* TODO : should we use skb->sk here instead of sk ? */ |
1da177e4 | 393 | skb->priority = sk->sk_priority; |
4a19ec58 | 394 | skb->mark = sk->sk_mark; |
1da177e4 | 395 | |
ab6e3feb ED |
396 | res = ip_local_out(skb); |
397 | rcu_read_unlock(); | |
398 | return res; | |
1da177e4 LT |
399 | |
400 | no_route: | |
ab6e3feb | 401 | rcu_read_unlock(); |
5e38e270 | 402 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); |
1da177e4 LT |
403 | kfree_skb(skb); |
404 | return -EHOSTUNREACH; | |
405 | } | |
4bc2f18b | 406 | EXPORT_SYMBOL(ip_queue_xmit); |
1da177e4 LT |
407 | |
408 | ||
409 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
410 | { | |
411 | to->pkt_type = from->pkt_type; | |
412 | to->priority = from->priority; | |
413 | to->protocol = from->protocol; | |
adf30907 | 414 | skb_dst_drop(to); |
fe76cda3 | 415 | skb_dst_copy(to, from); |
1da177e4 | 416 | to->dev = from->dev; |
82e91ffe | 417 | to->mark = from->mark; |
1da177e4 LT |
418 | |
419 | /* Copy the flags to each fragment. */ | |
420 | IPCB(to)->flags = IPCB(from)->flags; | |
421 | ||
422 | #ifdef CONFIG_NET_SCHED | |
423 | to->tc_index = from->tc_index; | |
424 | #endif | |
e7ac05f3 | 425 | nf_copy(to, from); |
c98d80ed JA |
426 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
427 | to->ipvs_property = from->ipvs_property; | |
1da177e4 | 428 | #endif |
984bc16c | 429 | skb_copy_secmark(to, from); |
1da177e4 LT |
430 | } |
431 | ||
432 | /* | |
433 | * This IP datagram is too large to be sent in one piece. Break it up into | |
434 | * smaller pieces (each of size equal to IP header plus | |
435 | * a block of the data of the original IP data part) that will yet fit in a | |
436 | * single device frame, and queue such a frame for sending. | |
437 | */ | |
438 | ||
d9319100 | 439 | int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) |
1da177e4 LT |
440 | { |
441 | struct iphdr *iph; | |
1da177e4 LT |
442 | int ptr; |
443 | struct net_device *dev; | |
444 | struct sk_buff *skb2; | |
c893b806 | 445 | unsigned int mtu, hlen, left, len, ll_rs; |
1da177e4 | 446 | int offset; |
76ab608d | 447 | __be16 not_last_frag; |
511c3f92 | 448 | struct rtable *rt = skb_rtable(skb); |
1da177e4 LT |
449 | int err = 0; |
450 | ||
d8d1f30b | 451 | dev = rt->dst.dev; |
1da177e4 LT |
452 | |
453 | /* | |
454 | * Point into the IP datagram header. | |
455 | */ | |
456 | ||
eddc9ec5 | 457 | iph = ip_hdr(skb); |
1da177e4 | 458 | |
69647ce4 | 459 | mtu = ip_skb_dst_mtu(skb); |
5f2d04f1 PM |
460 | if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->local_df) || |
461 | (IPCB(skb)->frag_max_size && | |
f87c10a8 | 462 | IPCB(skb)->frag_max_size > mtu))) { |
5e38e270 | 463 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
1da177e4 | 464 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, |
f87c10a8 | 465 | htonl(mtu)); |
1da177e4 LT |
466 | kfree_skb(skb); |
467 | return -EMSGSIZE; | |
468 | } | |
469 | ||
470 | /* | |
471 | * Setup starting values. | |
472 | */ | |
473 | ||
474 | hlen = iph->ihl * 4; | |
f87c10a8 | 475 | mtu = mtu - hlen; /* Size of data space */ |
6c79bf0f BDS |
476 | #ifdef CONFIG_BRIDGE_NETFILTER |
477 | if (skb->nf_bridge) | |
478 | mtu -= nf_bridge_mtu_reduction(skb); | |
479 | #endif | |
89cee8b1 | 480 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; |
1da177e4 LT |
481 | |
482 | /* When frag_list is given, use it. First, check its validity: | |
483 | * some transformers could create wrong frag_list or break existing | |
484 | * one, it is not prohibited. In this case fall back to copying. | |
485 | * | |
486 | * LATER: this step can be merged to real generation of fragments, | |
487 | * we can switch to copy when see the first bad fragment. | |
488 | */ | |
21dc3301 | 489 | if (skb_has_frag_list(skb)) { |
3d13008e | 490 | struct sk_buff *frag, *frag2; |
1da177e4 LT |
491 | int first_len = skb_pagelen(skb); |
492 | ||
493 | if (first_len - hlen > mtu || | |
494 | ((first_len - hlen) & 7) || | |
56f8a75c | 495 | ip_is_fragment(iph) || |
1da177e4 LT |
496 | skb_cloned(skb)) |
497 | goto slow_path; | |
498 | ||
d7fcf1a5 | 499 | skb_walk_frags(skb, frag) { |
1da177e4 LT |
500 | /* Correct geometry. */ |
501 | if (frag->len > mtu || | |
502 | ((frag->len & 7) && frag->next) || | |
503 | skb_headroom(frag) < hlen) | |
3d13008e | 504 | goto slow_path_clean; |
1da177e4 LT |
505 | |
506 | /* Partially cloned skb? */ | |
507 | if (skb_shared(frag)) | |
3d13008e | 508 | goto slow_path_clean; |
2fdba6b0 HX |
509 | |
510 | BUG_ON(frag->sk); | |
511 | if (skb->sk) { | |
2fdba6b0 HX |
512 | frag->sk = skb->sk; |
513 | frag->destructor = sock_wfree; | |
2fdba6b0 | 514 | } |
3d13008e | 515 | skb->truesize -= frag->truesize; |
1da177e4 LT |
516 | } |
517 | ||
518 | /* Everything is OK. Generate! */ | |
519 | ||
520 | err = 0; | |
521 | offset = 0; | |
522 | frag = skb_shinfo(skb)->frag_list; | |
d7fcf1a5 | 523 | skb_frag_list_init(skb); |
1da177e4 LT |
524 | skb->data_len = first_len - skb_headlen(skb); |
525 | skb->len = first_len; | |
526 | iph->tot_len = htons(first_len); | |
527 | iph->frag_off = htons(IP_MF); | |
528 | ip_send_check(iph); | |
529 | ||
530 | for (;;) { | |
531 | /* Prepare header of the next frame, | |
532 | * before previous one went down. */ | |
533 | if (frag) { | |
534 | frag->ip_summed = CHECKSUM_NONE; | |
badff6d0 | 535 | skb_reset_transport_header(frag); |
e2d1bca7 ACM |
536 | __skb_push(frag, hlen); |
537 | skb_reset_network_header(frag); | |
d56f90a7 | 538 | memcpy(skb_network_header(frag), iph, hlen); |
eddc9ec5 | 539 | iph = ip_hdr(frag); |
1da177e4 LT |
540 | iph->tot_len = htons(frag->len); |
541 | ip_copy_metadata(frag, skb); | |
542 | if (offset == 0) | |
543 | ip_options_fragment(frag); | |
544 | offset += skb->len - hlen; | |
545 | iph->frag_off = htons(offset>>3); | |
546 | if (frag->next != NULL) | |
547 | iph->frag_off |= htons(IP_MF); | |
548 | /* Ready, complete checksum */ | |
549 | ip_send_check(iph); | |
550 | } | |
551 | ||
552 | err = output(skb); | |
553 | ||
dafee490 | 554 | if (!err) |
5e38e270 | 555 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); |
1da177e4 LT |
556 | if (err || !frag) |
557 | break; | |
558 | ||
559 | skb = frag; | |
560 | frag = skb->next; | |
561 | skb->next = NULL; | |
562 | } | |
563 | ||
564 | if (err == 0) { | |
5e38e270 | 565 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); |
1da177e4 LT |
566 | return 0; |
567 | } | |
568 | ||
569 | while (frag) { | |
570 | skb = frag->next; | |
571 | kfree_skb(frag); | |
572 | frag = skb; | |
573 | } | |
5e38e270 | 574 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
1da177e4 | 575 | return err; |
3d13008e ED |
576 | |
577 | slow_path_clean: | |
578 | skb_walk_frags(skb, frag2) { | |
579 | if (frag2 == frag) | |
580 | break; | |
581 | frag2->sk = NULL; | |
582 | frag2->destructor = NULL; | |
583 | skb->truesize += frag2->truesize; | |
584 | } | |
1da177e4 LT |
585 | } |
586 | ||
587 | slow_path: | |
fc70fb64 AD |
588 | /* for offloaded checksums cleanup checksum before fragmentation */ |
589 | if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb)) | |
590 | goto fail; | |
c9af6db4 | 591 | iph = ip_hdr(skb); |
fc70fb64 | 592 | |
1da177e4 | 593 | left = skb->len - hlen; /* Space per frame */ |
49085bd7 | 594 | ptr = hlen; /* Where to start from */ |
1da177e4 | 595 | |
1da177e4 | 596 | /* for bridged IP traffic encapsulated inside f.e. a vlan header, |
9bcfcaf5 SH |
597 | * we need to make room for the encapsulating header |
598 | */ | |
c893b806 | 599 | ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb)); |
9bcfcaf5 | 600 | |
1da177e4 LT |
601 | /* |
602 | * Fragment the datagram. | |
603 | */ | |
604 | ||
605 | offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
606 | not_last_frag = iph->frag_off & htons(IP_MF); | |
607 | ||
608 | /* | |
609 | * Keep copying data until we run out. | |
610 | */ | |
611 | ||
132adf54 | 612 | while (left > 0) { |
1da177e4 LT |
613 | len = left; |
614 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
615 | if (len > mtu) | |
616 | len = mtu; | |
25985edc | 617 | /* IF: we are not sending up to and including the packet end |
1da177e4 LT |
618 | then align the next start on an eight byte boundary */ |
619 | if (len < left) { | |
620 | len &= ~7; | |
621 | } | |
622 | /* | |
623 | * Allocate buffer. | |
624 | */ | |
625 | ||
626 | if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) { | |
64ce2073 | 627 | NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n"); |
1da177e4 LT |
628 | err = -ENOMEM; |
629 | goto fail; | |
630 | } | |
631 | ||
632 | /* | |
633 | * Set up data on packet | |
634 | */ | |
635 | ||
636 | ip_copy_metadata(skb2, skb); | |
637 | skb_reserve(skb2, ll_rs); | |
638 | skb_put(skb2, len + hlen); | |
c1d2bbe1 | 639 | skb_reset_network_header(skb2); |
b0e380b1 | 640 | skb2->transport_header = skb2->network_header + hlen; |
1da177e4 LT |
641 | |
642 | /* | |
643 | * Charge the memory for the fragment to any owner | |
644 | * it might possess | |
645 | */ | |
646 | ||
647 | if (skb->sk) | |
648 | skb_set_owner_w(skb2, skb->sk); | |
649 | ||
650 | /* | |
651 | * Copy the packet header into the new buffer. | |
652 | */ | |
653 | ||
d626f62b | 654 | skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); |
1da177e4 LT |
655 | |
656 | /* | |
657 | * Copy a block of the IP datagram. | |
658 | */ | |
bff9b61c | 659 | if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) |
1da177e4 LT |
660 | BUG(); |
661 | left -= len; | |
662 | ||
663 | /* | |
664 | * Fill in the new header fields. | |
665 | */ | |
eddc9ec5 | 666 | iph = ip_hdr(skb2); |
1da177e4 LT |
667 | iph->frag_off = htons((offset >> 3)); |
668 | ||
669 | /* ANK: dirty, but effective trick. Upgrade options only if | |
670 | * the segment to be fragmented was THE FIRST (otherwise, | |
671 | * options are already fixed) and make it ONCE | |
672 | * on the initial skb, so that all the following fragments | |
673 | * will inherit fixed options. | |
674 | */ | |
675 | if (offset == 0) | |
676 | ip_options_fragment(skb); | |
677 | ||
678 | /* | |
679 | * Added AC : If we are fragmenting a fragment that's not the | |
680 | * last fragment then keep MF on each bit | |
681 | */ | |
682 | if (left > 0 || not_last_frag) | |
683 | iph->frag_off |= htons(IP_MF); | |
684 | ptr += len; | |
685 | offset += len; | |
686 | ||
687 | /* | |
688 | * Put this fragment into the sending queue. | |
689 | */ | |
1da177e4 LT |
690 | iph->tot_len = htons(len + hlen); |
691 | ||
692 | ip_send_check(iph); | |
693 | ||
694 | err = output(skb2); | |
695 | if (err) | |
696 | goto fail; | |
dafee490 | 697 | |
5e38e270 | 698 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES); |
1da177e4 | 699 | } |
5d0ba55b | 700 | consume_skb(skb); |
5e38e270 | 701 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS); |
1da177e4 LT |
702 | return err; |
703 | ||
704 | fail: | |
e905a9ed | 705 | kfree_skb(skb); |
5e38e270 | 706 | IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS); |
1da177e4 LT |
707 | return err; |
708 | } | |
2e2f7aef PM |
709 | EXPORT_SYMBOL(ip_fragment); |
710 | ||
1da177e4 LT |
711 | int |
712 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
713 | { | |
714 | struct iovec *iov = from; | |
715 | ||
84fa7933 | 716 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
1da177e4 LT |
717 | if (memcpy_fromiovecend(to, iov, offset, len) < 0) |
718 | return -EFAULT; | |
719 | } else { | |
44bb9363 | 720 | __wsum csum = 0; |
1da177e4 LT |
721 | if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0) |
722 | return -EFAULT; | |
723 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
724 | } | |
725 | return 0; | |
726 | } | |
4bc2f18b | 727 | EXPORT_SYMBOL(ip_generic_getfrag); |
1da177e4 | 728 | |
44bb9363 | 729 | static inline __wsum |
1da177e4 LT |
730 | csum_page(struct page *page, int offset, int copy) |
731 | { | |
732 | char *kaddr; | |
44bb9363 | 733 | __wsum csum; |
1da177e4 LT |
734 | kaddr = kmap(page); |
735 | csum = csum_partial(kaddr + offset, copy, 0); | |
736 | kunmap(page); | |
737 | return csum; | |
738 | } | |
739 | ||
4b30b1c6 | 740 | static inline int ip_ufo_append_data(struct sock *sk, |
1470ddf7 | 741 | struct sk_buff_head *queue, |
e89e9cf5 AR |
742 | int getfrag(void *from, char *to, int offset, int len, |
743 | int odd, struct sk_buff *skb), | |
744 | void *from, int length, int hh_len, int fragheaderlen, | |
d9be4f7a | 745 | int transhdrlen, int maxfraglen, unsigned int flags) |
e89e9cf5 AR |
746 | { |
747 | struct sk_buff *skb; | |
748 | int err; | |
749 | ||
750 | /* There is support for UDP fragmentation offload by network | |
751 | * device, so create one single skb packet containing complete | |
752 | * udp datagram | |
753 | */ | |
1470ddf7 | 754 | if ((skb = skb_peek_tail(queue)) == NULL) { |
e89e9cf5 AR |
755 | skb = sock_alloc_send_skb(sk, |
756 | hh_len + fragheaderlen + transhdrlen + 20, | |
757 | (flags & MSG_DONTWAIT), &err); | |
758 | ||
759 | if (skb == NULL) | |
760 | return err; | |
761 | ||
762 | /* reserve space for Hardware header */ | |
763 | skb_reserve(skb, hh_len); | |
764 | ||
765 | /* create space for UDP/IP header */ | |
d9319100 | 766 | skb_put(skb, fragheaderlen + transhdrlen); |
e89e9cf5 AR |
767 | |
768 | /* initialize network header pointer */ | |
c1d2bbe1 | 769 | skb_reset_network_header(skb); |
e89e9cf5 AR |
770 | |
771 | /* initialize protocol header pointer */ | |
b0e380b1 | 772 | skb->transport_header = skb->network_header + fragheaderlen; |
e89e9cf5 | 773 | |
e89e9cf5 | 774 | skb->csum = 0; |
e89e9cf5 | 775 | |
e93b7d74 | 776 | |
1470ddf7 | 777 | __skb_queue_tail(queue, skb); |
e93b7d74 JP |
778 | } else if (skb_is_gso(skb)) { |
779 | goto append; | |
e89e9cf5 | 780 | } |
be9164e7 | 781 | |
e93b7d74 JP |
782 | skb->ip_summed = CHECKSUM_PARTIAL; |
783 | /* specify the length of each IP datagram fragment */ | |
784 | skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen; | |
785 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
786 | ||
787 | append: | |
be9164e7 K |
788 | return skb_append_datato_frags(sk, skb, getfrag, from, |
789 | (length - transhdrlen)); | |
e89e9cf5 AR |
790 | } |
791 | ||
f5fca608 DM |
792 | static int __ip_append_data(struct sock *sk, |
793 | struct flowi4 *fl4, | |
794 | struct sk_buff_head *queue, | |
1470ddf7 | 795 | struct inet_cork *cork, |
5640f768 | 796 | struct page_frag *pfrag, |
1470ddf7 HX |
797 | int getfrag(void *from, char *to, int offset, |
798 | int len, int odd, struct sk_buff *skb), | |
799 | void *from, int length, int transhdrlen, | |
800 | unsigned int flags) | |
1da177e4 LT |
801 | { |
802 | struct inet_sock *inet = inet_sk(sk); | |
803 | struct sk_buff *skb; | |
804 | ||
07df5294 | 805 | struct ip_options *opt = cork->opt; |
1da177e4 LT |
806 | int hh_len; |
807 | int exthdrlen; | |
808 | int mtu; | |
809 | int copy; | |
810 | int err; | |
811 | int offset = 0; | |
daba287b | 812 | unsigned int maxfraglen, fragheaderlen, maxnonfragsize; |
1da177e4 | 813 | int csummode = CHECKSUM_NONE; |
1470ddf7 | 814 | struct rtable *rt = (struct rtable *)cork->dst; |
1da177e4 | 815 | |
96d7303e SK |
816 | skb = skb_peek_tail(queue); |
817 | ||
818 | exthdrlen = !skb ? rt->dst.header_len : 0; | |
07df5294 | 819 | mtu = cork->fragsize; |
1da177e4 | 820 | |
d8d1f30b | 821 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
1da177e4 LT |
822 | |
823 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
824 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1b346576 | 825 | maxnonfragsize = ip_sk_local_df(sk) ? 0xFFFF : mtu; |
1da177e4 | 826 | |
daba287b | 827 | if (cork->length + length > maxnonfragsize - fragheaderlen) { |
f5fca608 | 828 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, |
61e7f09d | 829 | mtu - (opt ? opt->optlen : 0)); |
1da177e4 LT |
830 | return -EMSGSIZE; |
831 | } | |
832 | ||
833 | /* | |
834 | * transhdrlen > 0 means that this is the first fragment and we wish | |
835 | * it won't be fragmented in the future. | |
836 | */ | |
837 | if (transhdrlen && | |
838 | length + fragheaderlen <= mtu && | |
d8d1f30b | 839 | rt->dst.dev->features & NETIF_F_V4_CSUM && |
1da177e4 | 840 | !exthdrlen) |
84fa7933 | 841 | csummode = CHECKSUM_PARTIAL; |
1da177e4 | 842 | |
1470ddf7 | 843 | cork->length += length; |
26cde9f7 | 844 | if (((length > mtu) || (skb && skb_is_gso(skb))) && |
be9164e7 | 845 | (sk->sk_protocol == IPPROTO_UDP) && |
c146066a | 846 | (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) { |
1470ddf7 HX |
847 | err = ip_ufo_append_data(sk, queue, getfrag, from, length, |
848 | hh_len, fragheaderlen, transhdrlen, | |
d9be4f7a | 849 | maxfraglen, flags); |
baa829d8 | 850 | if (err) |
e89e9cf5 | 851 | goto error; |
e89e9cf5 AR |
852 | return 0; |
853 | } | |
1da177e4 LT |
854 | |
855 | /* So, what's going on in the loop below? | |
856 | * | |
857 | * We use calculated fragment length to generate chained skb, | |
858 | * each of segments is IP fragment ready for sending to network after | |
859 | * adding appropriate IP header. | |
860 | */ | |
861 | ||
26cde9f7 | 862 | if (!skb) |
1da177e4 LT |
863 | goto alloc_new_skb; |
864 | ||
865 | while (length > 0) { | |
866 | /* Check if the remaining data fits into current packet. */ | |
867 | copy = mtu - skb->len; | |
868 | if (copy < length) | |
869 | copy = maxfraglen - skb->len; | |
870 | if (copy <= 0) { | |
871 | char *data; | |
872 | unsigned int datalen; | |
873 | unsigned int fraglen; | |
874 | unsigned int fraggap; | |
875 | unsigned int alloclen; | |
876 | struct sk_buff *skb_prev; | |
877 | alloc_new_skb: | |
878 | skb_prev = skb; | |
879 | if (skb_prev) | |
880 | fraggap = skb_prev->len - maxfraglen; | |
881 | else | |
882 | fraggap = 0; | |
883 | ||
884 | /* | |
885 | * If remaining data exceeds the mtu, | |
886 | * we know we need more fragment(s). | |
887 | */ | |
888 | datalen = length + fraggap; | |
889 | if (datalen > mtu - fragheaderlen) | |
890 | datalen = maxfraglen - fragheaderlen; | |
891 | fraglen = datalen + fragheaderlen; | |
892 | ||
e905a9ed | 893 | if ((flags & MSG_MORE) && |
d8d1f30b | 894 | !(rt->dst.dev->features&NETIF_F_SG)) |
1da177e4 LT |
895 | alloclen = mtu; |
896 | else | |
59104f06 | 897 | alloclen = fraglen; |
1da177e4 | 898 | |
353e5c9a SK |
899 | alloclen += exthdrlen; |
900 | ||
1da177e4 LT |
901 | /* The last fragment gets additional space at tail. |
902 | * Note, with MSG_MORE we overallocate on fragments, | |
903 | * because we have no idea what fragment will be | |
904 | * the last. | |
905 | */ | |
33f99dc7 | 906 | if (datalen == length + fraggap) |
d8d1f30b | 907 | alloclen += rt->dst.trailer_len; |
33f99dc7 | 908 | |
1da177e4 | 909 | if (transhdrlen) { |
e905a9ed | 910 | skb = sock_alloc_send_skb(sk, |
1da177e4 LT |
911 | alloclen + hh_len + 15, |
912 | (flags & MSG_DONTWAIT), &err); | |
913 | } else { | |
914 | skb = NULL; | |
915 | if (atomic_read(&sk->sk_wmem_alloc) <= | |
916 | 2 * sk->sk_sndbuf) | |
e905a9ed | 917 | skb = sock_wmalloc(sk, |
1da177e4 LT |
918 | alloclen + hh_len + 15, 1, |
919 | sk->sk_allocation); | |
920 | if (unlikely(skb == NULL)) | |
921 | err = -ENOBUFS; | |
51f31cab PO |
922 | else |
923 | /* only the initial fragment is | |
924 | time stamped */ | |
1470ddf7 | 925 | cork->tx_flags = 0; |
1da177e4 LT |
926 | } |
927 | if (skb == NULL) | |
928 | goto error; | |
929 | ||
930 | /* | |
931 | * Fill in the control structures | |
932 | */ | |
933 | skb->ip_summed = csummode; | |
934 | skb->csum = 0; | |
935 | skb_reserve(skb, hh_len); | |
1470ddf7 | 936 | skb_shinfo(skb)->tx_flags = cork->tx_flags; |
1da177e4 LT |
937 | |
938 | /* | |
939 | * Find where to start putting bytes. | |
940 | */ | |
353e5c9a | 941 | data = skb_put(skb, fraglen + exthdrlen); |
c14d2450 | 942 | skb_set_network_header(skb, exthdrlen); |
b0e380b1 ACM |
943 | skb->transport_header = (skb->network_header + |
944 | fragheaderlen); | |
353e5c9a | 945 | data += fragheaderlen + exthdrlen; |
1da177e4 LT |
946 | |
947 | if (fraggap) { | |
948 | skb->csum = skb_copy_and_csum_bits( | |
949 | skb_prev, maxfraglen, | |
950 | data + transhdrlen, fraggap, 0); | |
951 | skb_prev->csum = csum_sub(skb_prev->csum, | |
952 | skb->csum); | |
953 | data += fraggap; | |
e9fa4f7b | 954 | pskb_trim_unique(skb_prev, maxfraglen); |
1da177e4 LT |
955 | } |
956 | ||
957 | copy = datalen - transhdrlen - fraggap; | |
958 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
959 | err = -EFAULT; | |
960 | kfree_skb(skb); | |
961 | goto error; | |
962 | } | |
963 | ||
964 | offset += copy; | |
965 | length -= datalen - fraggap; | |
966 | transhdrlen = 0; | |
967 | exthdrlen = 0; | |
968 | csummode = CHECKSUM_NONE; | |
969 | ||
970 | /* | |
971 | * Put the packet on the pending queue. | |
972 | */ | |
1470ddf7 | 973 | __skb_queue_tail(queue, skb); |
1da177e4 LT |
974 | continue; |
975 | } | |
976 | ||
977 | if (copy > length) | |
978 | copy = length; | |
979 | ||
d8d1f30b | 980 | if (!(rt->dst.dev->features&NETIF_F_SG)) { |
1da177e4 LT |
981 | unsigned int off; |
982 | ||
983 | off = skb->len; | |
e905a9ed | 984 | if (getfrag(from, skb_put(skb, copy), |
1da177e4 LT |
985 | offset, copy, off, skb) < 0) { |
986 | __skb_trim(skb, off); | |
987 | err = -EFAULT; | |
988 | goto error; | |
989 | } | |
990 | } else { | |
991 | int i = skb_shinfo(skb)->nr_frags; | |
1da177e4 | 992 | |
5640f768 ED |
993 | err = -ENOMEM; |
994 | if (!sk_page_frag_refill(sk, pfrag)) | |
1da177e4 | 995 | goto error; |
5640f768 ED |
996 | |
997 | if (!skb_can_coalesce(skb, i, pfrag->page, | |
998 | pfrag->offset)) { | |
999 | err = -EMSGSIZE; | |
1000 | if (i == MAX_SKB_FRAGS) | |
1001 | goto error; | |
1002 | ||
1003 | __skb_fill_page_desc(skb, i, pfrag->page, | |
1004 | pfrag->offset, 0); | |
1005 | skb_shinfo(skb)->nr_frags = ++i; | |
1006 | get_page(pfrag->page); | |
1da177e4 | 1007 | } |
5640f768 ED |
1008 | copy = min_t(int, copy, pfrag->size - pfrag->offset); |
1009 | if (getfrag(from, | |
1010 | page_address(pfrag->page) + pfrag->offset, | |
1011 | offset, copy, skb->len, skb) < 0) | |
1012 | goto error_efault; | |
1013 | ||
1014 | pfrag->offset += copy; | |
1015 | skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); | |
1da177e4 LT |
1016 | skb->len += copy; |
1017 | skb->data_len += copy; | |
f945fa7a HX |
1018 | skb->truesize += copy; |
1019 | atomic_add(copy, &sk->sk_wmem_alloc); | |
1da177e4 LT |
1020 | } |
1021 | offset += copy; | |
1022 | length -= copy; | |
1023 | } | |
1024 | ||
1025 | return 0; | |
1026 | ||
5640f768 ED |
1027 | error_efault: |
1028 | err = -EFAULT; | |
1da177e4 | 1029 | error: |
1470ddf7 | 1030 | cork->length -= length; |
5e38e270 | 1031 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
e905a9ed | 1032 | return err; |
1da177e4 LT |
1033 | } |
1034 | ||
1470ddf7 HX |
1035 | static int ip_setup_cork(struct sock *sk, struct inet_cork *cork, |
1036 | struct ipcm_cookie *ipc, struct rtable **rtp) | |
1037 | { | |
f6d8bd05 | 1038 | struct ip_options_rcu *opt; |
1470ddf7 HX |
1039 | struct rtable *rt; |
1040 | ||
1041 | /* | |
1042 | * setup for corking. | |
1043 | */ | |
1044 | opt = ipc->opt; | |
1045 | if (opt) { | |
1046 | if (cork->opt == NULL) { | |
1047 | cork->opt = kmalloc(sizeof(struct ip_options) + 40, | |
1048 | sk->sk_allocation); | |
1049 | if (unlikely(cork->opt == NULL)) | |
1050 | return -ENOBUFS; | |
1051 | } | |
f6d8bd05 | 1052 | memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen); |
1470ddf7 HX |
1053 | cork->flags |= IPCORK_OPT; |
1054 | cork->addr = ipc->addr; | |
1055 | } | |
1056 | rt = *rtp; | |
1057 | if (unlikely(!rt)) | |
1058 | return -EFAULT; | |
1059 | /* | |
1060 | * We steal reference to this route, caller should not release it | |
1061 | */ | |
1062 | *rtp = NULL; | |
482fc609 HFS |
1063 | cork->fragsize = ip_sk_use_pmtu(sk) ? |
1064 | dst_mtu(&rt->dst) : rt->dst.dev->mtu; | |
1470ddf7 HX |
1065 | cork->dst = &rt->dst; |
1066 | cork->length = 0; | |
aa661581 FF |
1067 | cork->ttl = ipc->ttl; |
1068 | cork->tos = ipc->tos; | |
1069 | cork->priority = ipc->priority; | |
1470ddf7 | 1070 | cork->tx_flags = ipc->tx_flags; |
1470ddf7 HX |
1071 | |
1072 | return 0; | |
1073 | } | |
1074 | ||
1075 | /* | |
1076 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
1077 | * from many pieces of data. Each pieces will be holded on the socket | |
1078 | * until ip_push_pending_frames() is called. Each piece can be a page | |
1079 | * or non-page data. | |
1080 | * | |
1081 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
1082 | * this interface potentially. | |
1083 | * | |
1084 | * LATER: length must be adjusted by pad at tail, when it is required. | |
1085 | */ | |
f5fca608 | 1086 | int ip_append_data(struct sock *sk, struct flowi4 *fl4, |
1470ddf7 HX |
1087 | int getfrag(void *from, char *to, int offset, int len, |
1088 | int odd, struct sk_buff *skb), | |
1089 | void *from, int length, int transhdrlen, | |
1090 | struct ipcm_cookie *ipc, struct rtable **rtp, | |
1091 | unsigned int flags) | |
1092 | { | |
1093 | struct inet_sock *inet = inet_sk(sk); | |
1094 | int err; | |
1095 | ||
1096 | if (flags&MSG_PROBE) | |
1097 | return 0; | |
1098 | ||
1099 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
bdc712b4 | 1100 | err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp); |
1470ddf7 HX |
1101 | if (err) |
1102 | return err; | |
1103 | } else { | |
1104 | transhdrlen = 0; | |
1105 | } | |
1106 | ||
5640f768 ED |
1107 | return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base, |
1108 | sk_page_frag(sk), getfrag, | |
1470ddf7 HX |
1109 | from, length, transhdrlen, flags); |
1110 | } | |
1111 | ||
f5fca608 | 1112 | ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, |
1da177e4 LT |
1113 | int offset, size_t size, int flags) |
1114 | { | |
1115 | struct inet_sock *inet = inet_sk(sk); | |
1116 | struct sk_buff *skb; | |
1117 | struct rtable *rt; | |
1118 | struct ip_options *opt = NULL; | |
bdc712b4 | 1119 | struct inet_cork *cork; |
1da177e4 LT |
1120 | int hh_len; |
1121 | int mtu; | |
1122 | int len; | |
1123 | int err; | |
daba287b | 1124 | unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize; |
1da177e4 LT |
1125 | |
1126 | if (inet->hdrincl) | |
1127 | return -EPERM; | |
1128 | ||
1129 | if (flags&MSG_PROBE) | |
1130 | return 0; | |
1131 | ||
1132 | if (skb_queue_empty(&sk->sk_write_queue)) | |
1133 | return -EINVAL; | |
1134 | ||
bdc712b4 DM |
1135 | cork = &inet->cork.base; |
1136 | rt = (struct rtable *)cork->dst; | |
1137 | if (cork->flags & IPCORK_OPT) | |
1138 | opt = cork->opt; | |
1da177e4 | 1139 | |
d8d1f30b | 1140 | if (!(rt->dst.dev->features&NETIF_F_SG)) |
1da177e4 LT |
1141 | return -EOPNOTSUPP; |
1142 | ||
d8d1f30b | 1143 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
bdc712b4 | 1144 | mtu = cork->fragsize; |
1da177e4 LT |
1145 | |
1146 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1147 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1b346576 | 1148 | maxnonfragsize = ip_sk_local_df(sk) ? 0xFFFF : mtu; |
1da177e4 | 1149 | |
daba287b | 1150 | if (cork->length + size > maxnonfragsize - fragheaderlen) { |
61e7f09d HFS |
1151 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, |
1152 | mtu - (opt ? opt->optlen : 0)); | |
1da177e4 LT |
1153 | return -EMSGSIZE; |
1154 | } | |
1155 | ||
1156 | if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) | |
1157 | return -EINVAL; | |
1158 | ||
bdc712b4 | 1159 | cork->length += size; |
26cde9f7 HX |
1160 | if ((size + skb->len > mtu) && |
1161 | (sk->sk_protocol == IPPROTO_UDP) && | |
d8d1f30b | 1162 | (rt->dst.dev->features & NETIF_F_UFO)) { |
7967168c | 1163 | skb_shinfo(skb)->gso_size = mtu - fragheaderlen; |
f83ef8c0 | 1164 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; |
7967168c | 1165 | } |
e89e9cf5 | 1166 | |
1da177e4 LT |
1167 | |
1168 | while (size > 0) { | |
1169 | int i; | |
1170 | ||
89114afd | 1171 | if (skb_is_gso(skb)) |
e89e9cf5 AR |
1172 | len = size; |
1173 | else { | |
1174 | ||
1175 | /* Check if the remaining data fits into current packet. */ | |
1176 | len = mtu - skb->len; | |
1177 | if (len < size) | |
1178 | len = maxfraglen - skb->len; | |
1179 | } | |
1da177e4 LT |
1180 | if (len <= 0) { |
1181 | struct sk_buff *skb_prev; | |
1da177e4 LT |
1182 | int alloclen; |
1183 | ||
1184 | skb_prev = skb; | |
0d0d2bba | 1185 | fraggap = skb_prev->len - maxfraglen; |
1da177e4 LT |
1186 | |
1187 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1188 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1189 | if (unlikely(!skb)) { | |
1190 | err = -ENOBUFS; | |
1191 | goto error; | |
1192 | } | |
1193 | ||
1194 | /* | |
1195 | * Fill in the control structures | |
1196 | */ | |
1197 | skb->ip_summed = CHECKSUM_NONE; | |
1198 | skb->csum = 0; | |
1199 | skb_reserve(skb, hh_len); | |
1200 | ||
1201 | /* | |
1202 | * Find where to start putting bytes. | |
1203 | */ | |
967b05f6 | 1204 | skb_put(skb, fragheaderlen + fraggap); |
2ca9e6f2 | 1205 | skb_reset_network_header(skb); |
b0e380b1 ACM |
1206 | skb->transport_header = (skb->network_header + |
1207 | fragheaderlen); | |
1da177e4 | 1208 | if (fraggap) { |
967b05f6 ACM |
1209 | skb->csum = skb_copy_and_csum_bits(skb_prev, |
1210 | maxfraglen, | |
9c70220b | 1211 | skb_transport_header(skb), |
967b05f6 | 1212 | fraggap, 0); |
1da177e4 LT |
1213 | skb_prev->csum = csum_sub(skb_prev->csum, |
1214 | skb->csum); | |
e9fa4f7b | 1215 | pskb_trim_unique(skb_prev, maxfraglen); |
1da177e4 LT |
1216 | } |
1217 | ||
1218 | /* | |
1219 | * Put the packet on the pending queue. | |
1220 | */ | |
1221 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1222 | continue; | |
1223 | } | |
1224 | ||
1225 | i = skb_shinfo(skb)->nr_frags; | |
1226 | if (len > size) | |
1227 | len = size; | |
1228 | if (skb_can_coalesce(skb, i, page, offset)) { | |
9e903e08 | 1229 | skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len); |
1da177e4 LT |
1230 | } else if (i < MAX_SKB_FRAGS) { |
1231 | get_page(page); | |
1232 | skb_fill_page_desc(skb, i, page, offset, len); | |
1233 | } else { | |
1234 | err = -EMSGSIZE; | |
1235 | goto error; | |
1236 | } | |
1237 | ||
1238 | if (skb->ip_summed == CHECKSUM_NONE) { | |
44bb9363 | 1239 | __wsum csum; |
1da177e4 LT |
1240 | csum = csum_page(page, offset, len); |
1241 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1242 | } | |
1243 | ||
1244 | skb->len += len; | |
1245 | skb->data_len += len; | |
1e34a11d DM |
1246 | skb->truesize += len; |
1247 | atomic_add(len, &sk->sk_wmem_alloc); | |
1da177e4 LT |
1248 | offset += len; |
1249 | size -= len; | |
1250 | } | |
1251 | return 0; | |
1252 | ||
1253 | error: | |
bdc712b4 | 1254 | cork->length -= size; |
5e38e270 | 1255 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
1da177e4 LT |
1256 | return err; |
1257 | } | |
1258 | ||
1470ddf7 | 1259 | static void ip_cork_release(struct inet_cork *cork) |
429f08e9 | 1260 | { |
1470ddf7 HX |
1261 | cork->flags &= ~IPCORK_OPT; |
1262 | kfree(cork->opt); | |
1263 | cork->opt = NULL; | |
1264 | dst_release(cork->dst); | |
1265 | cork->dst = NULL; | |
429f08e9 PE |
1266 | } |
1267 | ||
1da177e4 LT |
1268 | /* |
1269 | * Combined all pending IP fragments on the socket as one IP datagram | |
1270 | * and push them out. | |
1271 | */ | |
1c32c5ad | 1272 | struct sk_buff *__ip_make_skb(struct sock *sk, |
77968b78 | 1273 | struct flowi4 *fl4, |
1c32c5ad HX |
1274 | struct sk_buff_head *queue, |
1275 | struct inet_cork *cork) | |
1da177e4 LT |
1276 | { |
1277 | struct sk_buff *skb, *tmp_skb; | |
1278 | struct sk_buff **tail_skb; | |
1279 | struct inet_sock *inet = inet_sk(sk); | |
0388b004 | 1280 | struct net *net = sock_net(sk); |
1da177e4 | 1281 | struct ip_options *opt = NULL; |
1470ddf7 | 1282 | struct rtable *rt = (struct rtable *)cork->dst; |
1da177e4 | 1283 | struct iphdr *iph; |
76ab608d | 1284 | __be16 df = 0; |
1da177e4 | 1285 | __u8 ttl; |
1da177e4 | 1286 | |
1470ddf7 | 1287 | if ((skb = __skb_dequeue(queue)) == NULL) |
1da177e4 LT |
1288 | goto out; |
1289 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1290 | ||
1291 | /* move skb->data to ip header from ext header */ | |
d56f90a7 | 1292 | if (skb->data < skb_network_header(skb)) |
bbe735e4 | 1293 | __skb_pull(skb, skb_network_offset(skb)); |
1470ddf7 | 1294 | while ((tmp_skb = __skb_dequeue(queue)) != NULL) { |
cfe1fc77 | 1295 | __skb_pull(tmp_skb, skb_network_header_len(skb)); |
1da177e4 LT |
1296 | *tail_skb = tmp_skb; |
1297 | tail_skb = &(tmp_skb->next); | |
1298 | skb->len += tmp_skb->len; | |
1299 | skb->data_len += tmp_skb->len; | |
1300 | skb->truesize += tmp_skb->truesize; | |
1da177e4 LT |
1301 | tmp_skb->destructor = NULL; |
1302 | tmp_skb->sk = NULL; | |
1303 | } | |
1304 | ||
1305 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1306 | * to fragment the frame generated here. No matter, what transforms | |
1307 | * how transforms change size of the packet, it will come out. | |
1308 | */ | |
1b346576 | 1309 | skb->local_df = ip_sk_local_df(sk); |
1da177e4 LT |
1310 | |
1311 | /* DF bit is set when we want to see DF on outgoing frames. | |
1312 | * If local_df is set too, we still allow to fragment this frame | |
1313 | * locally. */ | |
482fc609 HFS |
1314 | if (inet->pmtudisc == IP_PMTUDISC_DO || |
1315 | inet->pmtudisc == IP_PMTUDISC_PROBE || | |
d8d1f30b CG |
1316 | (skb->len <= dst_mtu(&rt->dst) && |
1317 | ip_dont_fragment(sk, &rt->dst))) | |
1da177e4 LT |
1318 | df = htons(IP_DF); |
1319 | ||
1470ddf7 HX |
1320 | if (cork->flags & IPCORK_OPT) |
1321 | opt = cork->opt; | |
1da177e4 | 1322 | |
aa661581 FF |
1323 | if (cork->ttl != 0) |
1324 | ttl = cork->ttl; | |
1325 | else if (rt->rt_type == RTN_MULTICAST) | |
1da177e4 LT |
1326 | ttl = inet->mc_ttl; |
1327 | else | |
d8d1f30b | 1328 | ttl = ip_select_ttl(inet, &rt->dst); |
1da177e4 | 1329 | |
749154aa | 1330 | iph = ip_hdr(skb); |
1da177e4 LT |
1331 | iph->version = 4; |
1332 | iph->ihl = 5; | |
aa661581 | 1333 | iph->tos = (cork->tos != -1) ? cork->tos : inet->tos; |
1da177e4 | 1334 | iph->frag_off = df; |
1da177e4 LT |
1335 | iph->ttl = ttl; |
1336 | iph->protocol = sk->sk_protocol; | |
84f9307c | 1337 | ip_copy_addrs(iph, fl4); |
703133de | 1338 | ip_select_ident(skb, &rt->dst, sk); |
1da177e4 | 1339 | |
22f728f8 DM |
1340 | if (opt) { |
1341 | iph->ihl += opt->optlen>>2; | |
1342 | ip_options_build(skb, opt, cork->addr, rt, 0); | |
1343 | } | |
1344 | ||
aa661581 | 1345 | skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority; |
4a19ec58 | 1346 | skb->mark = sk->sk_mark; |
a21bba94 ED |
1347 | /* |
1348 | * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec | |
1349 | * on dst refcount | |
1350 | */ | |
1470ddf7 | 1351 | cork->dst = NULL; |
d8d1f30b | 1352 | skb_dst_set(skb, &rt->dst); |
1da177e4 | 1353 | |
96793b48 | 1354 | if (iph->protocol == IPPROTO_ICMP) |
0388b004 | 1355 | icmp_out_count(net, ((struct icmphdr *) |
96793b48 DS |
1356 | skb_transport_header(skb))->type); |
1357 | ||
1c32c5ad HX |
1358 | ip_cork_release(cork); |
1359 | out: | |
1360 | return skb; | |
1361 | } | |
1362 | ||
b5ec8eea | 1363 | int ip_send_skb(struct net *net, struct sk_buff *skb) |
1c32c5ad | 1364 | { |
1c32c5ad HX |
1365 | int err; |
1366 | ||
c439cb2e | 1367 | err = ip_local_out(skb); |
1da177e4 LT |
1368 | if (err) { |
1369 | if (err > 0) | |
6ce9e7b5 | 1370 | err = net_xmit_errno(err); |
1da177e4 | 1371 | if (err) |
1c32c5ad | 1372 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); |
1da177e4 LT |
1373 | } |
1374 | ||
1da177e4 | 1375 | return err; |
1da177e4 LT |
1376 | } |
1377 | ||
77968b78 | 1378 | int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4) |
1470ddf7 | 1379 | { |
1c32c5ad HX |
1380 | struct sk_buff *skb; |
1381 | ||
77968b78 | 1382 | skb = ip_finish_skb(sk, fl4); |
1c32c5ad HX |
1383 | if (!skb) |
1384 | return 0; | |
1385 | ||
1386 | /* Netfilter gets whole the not fragmented skb. */ | |
b5ec8eea | 1387 | return ip_send_skb(sock_net(sk), skb); |
1470ddf7 HX |
1388 | } |
1389 | ||
1da177e4 LT |
1390 | /* |
1391 | * Throw away all pending data on the socket. | |
1392 | */ | |
1470ddf7 HX |
1393 | static void __ip_flush_pending_frames(struct sock *sk, |
1394 | struct sk_buff_head *queue, | |
1395 | struct inet_cork *cork) | |
1da177e4 | 1396 | { |
1da177e4 LT |
1397 | struct sk_buff *skb; |
1398 | ||
1470ddf7 | 1399 | while ((skb = __skb_dequeue_tail(queue)) != NULL) |
1da177e4 LT |
1400 | kfree_skb(skb); |
1401 | ||
1470ddf7 HX |
1402 | ip_cork_release(cork); |
1403 | } | |
1404 | ||
1405 | void ip_flush_pending_frames(struct sock *sk) | |
1406 | { | |
bdc712b4 | 1407 | __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base); |
1da177e4 LT |
1408 | } |
1409 | ||
1c32c5ad | 1410 | struct sk_buff *ip_make_skb(struct sock *sk, |
77968b78 | 1411 | struct flowi4 *fl4, |
1c32c5ad HX |
1412 | int getfrag(void *from, char *to, int offset, |
1413 | int len, int odd, struct sk_buff *skb), | |
1414 | void *from, int length, int transhdrlen, | |
1415 | struct ipcm_cookie *ipc, struct rtable **rtp, | |
1416 | unsigned int flags) | |
1417 | { | |
b80d7226 | 1418 | struct inet_cork cork; |
1c32c5ad HX |
1419 | struct sk_buff_head queue; |
1420 | int err; | |
1421 | ||
1422 | if (flags & MSG_PROBE) | |
1423 | return NULL; | |
1424 | ||
1425 | __skb_queue_head_init(&queue); | |
1426 | ||
b80d7226 DM |
1427 | cork.flags = 0; |
1428 | cork.addr = 0; | |
70652728 | 1429 | cork.opt = NULL; |
1c32c5ad HX |
1430 | err = ip_setup_cork(sk, &cork, ipc, rtp); |
1431 | if (err) | |
1432 | return ERR_PTR(err); | |
1433 | ||
5640f768 ED |
1434 | err = __ip_append_data(sk, fl4, &queue, &cork, |
1435 | ¤t->task_frag, getfrag, | |
1c32c5ad HX |
1436 | from, length, transhdrlen, flags); |
1437 | if (err) { | |
1438 | __ip_flush_pending_frames(sk, &queue, &cork); | |
1439 | return ERR_PTR(err); | |
1440 | } | |
1441 | ||
77968b78 | 1442 | return __ip_make_skb(sk, fl4, &queue, &cork); |
1c32c5ad | 1443 | } |
1da177e4 LT |
1444 | |
1445 | /* | |
1446 | * Fetch data from kernel space and fill in checksum if needed. | |
1447 | */ | |
e905a9ed | 1448 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, |
1da177e4 LT |
1449 | int len, int odd, struct sk_buff *skb) |
1450 | { | |
5084205f | 1451 | __wsum csum; |
1da177e4 LT |
1452 | |
1453 | csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0); | |
1454 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
e905a9ed | 1455 | return 0; |
1da177e4 LT |
1456 | } |
1457 | ||
e905a9ed | 1458 | /* |
1da177e4 | 1459 | * Generic function to send a packet as reply to another packet. |
be9f4a44 | 1460 | * Used to send some TCP resets/acks so far. |
1da177e4 | 1461 | * |
be9f4a44 | 1462 | * Use a fake percpu inet socket to avoid false sharing and contention. |
1da177e4 | 1463 | */ |
be9f4a44 ED |
1464 | static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = { |
1465 | .sk = { | |
1466 | .__sk_common = { | |
1467 | .skc_refcnt = ATOMIC_INIT(1), | |
1468 | }, | |
1469 | .sk_wmem_alloc = ATOMIC_INIT(1), | |
1470 | .sk_allocation = GFP_ATOMIC, | |
1471 | .sk_flags = (1UL << SOCK_USE_WRITE_QUEUE), | |
1472 | }, | |
0980e56e ED |
1473 | .pmtudisc = IP_PMTUDISC_WANT, |
1474 | .uc_ttl = -1, | |
be9f4a44 ED |
1475 | }; |
1476 | ||
1477 | void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, | |
70e73416 DM |
1478 | __be32 saddr, const struct ip_reply_arg *arg, |
1479 | unsigned int len) | |
1da177e4 | 1480 | { |
f6d8bd05 | 1481 | struct ip_options_data replyopts; |
1da177e4 | 1482 | struct ipcm_cookie ipc; |
77968b78 | 1483 | struct flowi4 fl4; |
511c3f92 | 1484 | struct rtable *rt = skb_rtable(skb); |
be9f4a44 ED |
1485 | struct sk_buff *nskb; |
1486 | struct sock *sk; | |
1487 | struct inet_sock *inet; | |
1da177e4 | 1488 | |
f6d8bd05 | 1489 | if (ip_options_echo(&replyopts.opt.opt, skb)) |
1da177e4 LT |
1490 | return; |
1491 | ||
0a5ebb80 | 1492 | ipc.addr = daddr; |
1da177e4 | 1493 | ipc.opt = NULL; |
2244d07b | 1494 | ipc.tx_flags = 0; |
aa661581 FF |
1495 | ipc.ttl = 0; |
1496 | ipc.tos = -1; | |
1da177e4 | 1497 | |
f6d8bd05 | 1498 | if (replyopts.opt.opt.optlen) { |
1da177e4 LT |
1499 | ipc.opt = &replyopts.opt; |
1500 | ||
f6d8bd05 ED |
1501 | if (replyopts.opt.opt.srr) |
1502 | daddr = replyopts.opt.opt.faddr; | |
1da177e4 LT |
1503 | } |
1504 | ||
77968b78 | 1505 | flowi4_init_output(&fl4, arg->bound_dev_if, 0, |
66b13d99 | 1506 | RT_TOS(arg->tos), |
be9f4a44 | 1507 | RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol, |
77968b78 | 1508 | ip_reply_arg_flowi_flags(arg), |
70e73416 | 1509 | daddr, saddr, |
77968b78 DM |
1510 | tcp_hdr(skb)->source, tcp_hdr(skb)->dest); |
1511 | security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); | |
be9f4a44 | 1512 | rt = ip_route_output_key(net, &fl4); |
77968b78 DM |
1513 | if (IS_ERR(rt)) |
1514 | return; | |
1da177e4 | 1515 | |
be9f4a44 | 1516 | inet = &get_cpu_var(unicast_sock); |
1da177e4 | 1517 | |
66b13d99 | 1518 | inet->tos = arg->tos; |
be9f4a44 | 1519 | sk = &inet->sk; |
1da177e4 | 1520 | sk->sk_priority = skb->priority; |
eddc9ec5 | 1521 | sk->sk_protocol = ip_hdr(skb)->protocol; |
f0e48dbf | 1522 | sk->sk_bound_dev_if = arg->bound_dev_if; |
be9f4a44 ED |
1523 | sock_net_set(sk, net); |
1524 | __skb_queue_head_init(&sk->sk_write_queue); | |
1525 | sk->sk_sndbuf = sysctl_wmem_default; | |
f5fca608 | 1526 | ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0, |
2e77d89b | 1527 | &ipc, &rt, MSG_DONTWAIT); |
be9f4a44 ED |
1528 | nskb = skb_peek(&sk->sk_write_queue); |
1529 | if (nskb) { | |
1da177e4 | 1530 | if (arg->csumoffset >= 0) |
be9f4a44 ED |
1531 | *((__sum16 *)skb_transport_header(nskb) + |
1532 | arg->csumoffset) = csum_fold(csum_add(nskb->csum, | |
9c70220b | 1533 | arg->csum)); |
be9f4a44 | 1534 | nskb->ip_summed = CHECKSUM_NONE; |
3a7c384f | 1535 | skb_orphan(nskb); |
be9f4a44 | 1536 | skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb)); |
77968b78 | 1537 | ip_push_pending_frames(sk, &fl4); |
1da177e4 LT |
1538 | } |
1539 | ||
be9f4a44 | 1540 | put_cpu_var(unicast_sock); |
1da177e4 LT |
1541 | |
1542 | ip_rt_put(rt); | |
1543 | } | |
1544 | ||
1da177e4 LT |
1545 | void __init ip_init(void) |
1546 | { | |
1da177e4 LT |
1547 | ip_rt_init(); |
1548 | inet_initpeers(); | |
1549 | ||
72c1d3bd WC |
1550 | #if defined(CONFIG_IP_MULTICAST) |
1551 | igmp_mc_init(); | |
1da177e4 LT |
1552 | #endif |
1553 | } |