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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
4 | * operating system. INET is implemented using the BSD Socket | |
5 | * interface as the means of communication with the user level. | |
6 | * | |
7 | * The Internet Protocol (IP) output module. | |
8 | * | |
9 | * Authors: Ross Biro | |
10 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> | |
11 | * Donald Becker, <becker@super.org> | |
12 | * Alan Cox, <Alan.Cox@linux.org> | |
13 | * Richard Underwood | |
14 | * Stefan Becker, <stefanb@yello.ping.de> | |
15 | * Jorge Cwik, <jorge@laser.satlink.net> | |
16 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | |
17 | * Hirokazu Takahashi, <taka@valinux.co.jp> | |
18 | * | |
19 | * See ip_input.c for original log | |
20 | * | |
21 | * Fixes: | |
22 | * Alan Cox : Missing nonblock feature in ip_build_xmit. | |
23 | * Mike Kilburn : htons() missing in ip_build_xmit. | |
24 | * Bradford Johnson: Fix faulty handling of some frames when | |
25 | * no route is found. | |
26 | * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit | |
27 | * (in case if packet not accepted by | |
28 | * output firewall rules) | |
29 | * Mike McLagan : Routing by source | |
30 | * Alexey Kuznetsov: use new route cache | |
31 | * Andi Kleen: Fix broken PMTU recovery and remove | |
32 | * some redundant tests. | |
33 | * Vitaly E. Lavrov : Transparent proxy revived after year coma. | |
34 | * Andi Kleen : Replace ip_reply with ip_send_reply. | |
35 | * Andi Kleen : Split fast and slow ip_build_xmit path | |
36 | * for decreased register pressure on x86 | |
37 | * and more readibility. | |
38 | * Marc Boucher : When call_out_firewall returns FW_QUEUE, | |
39 | * silently drop skb instead of failing with -EPERM. | |
40 | * Detlev Wengorz : Copy protocol for fragments. | |
41 | * Hirokazu Takahashi: HW checksumming for outgoing UDP | |
42 | * datagrams. | |
43 | * Hirokazu Takahashi: sendfile() on UDP works now. | |
44 | */ | |
45 | ||
46 | #include <linux/uaccess.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 <net/inet_ecn.h> | |
78 | #include <net/lwtunnel.h> | |
79 | #include <linux/bpf-cgroup.h> | |
80 | #include <linux/igmp.h> | |
81 | #include <linux/netfilter_ipv4.h> | |
82 | #include <linux/netfilter_bridge.h> | |
83 | #include <linux/netlink.h> | |
84 | #include <linux/tcp.h> | |
85 | ||
86 | static int | |
87 | ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, | |
88 | unsigned int mtu, | |
89 | int (*output)(struct net *, struct sock *, struct sk_buff *)); | |
90 | ||
91 | /* Generate a checksum for an outgoing IP datagram. */ | |
92 | void ip_send_check(struct iphdr *iph) | |
93 | { | |
94 | iph->check = 0; | |
95 | iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); | |
96 | } | |
97 | EXPORT_SYMBOL(ip_send_check); | |
98 | ||
99 | int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) | |
100 | { | |
101 | struct iphdr *iph = ip_hdr(skb); | |
102 | ||
103 | iph->tot_len = htons(skb->len); | |
104 | ip_send_check(iph); | |
105 | ||
106 | /* if egress device is enslaved to an L3 master device pass the | |
107 | * skb to its handler for processing | |
108 | */ | |
109 | skb = l3mdev_ip_out(sk, skb); | |
110 | if (unlikely(!skb)) | |
111 | return 0; | |
112 | ||
113 | skb->protocol = htons(ETH_P_IP); | |
114 | ||
115 | return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, | |
116 | net, sk, skb, NULL, skb_dst(skb)->dev, | |
117 | dst_output); | |
118 | } | |
119 | ||
120 | int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) | |
121 | { | |
122 | int err; | |
123 | ||
124 | err = __ip_local_out(net, sk, skb); | |
125 | if (likely(err == 1)) | |
126 | err = dst_output(net, sk, skb); | |
127 | ||
128 | return err; | |
129 | } | |
130 | EXPORT_SYMBOL_GPL(ip_local_out); | |
131 | ||
132 | static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) | |
133 | { | |
134 | int ttl = inet->uc_ttl; | |
135 | ||
136 | if (ttl < 0) | |
137 | ttl = ip4_dst_hoplimit(dst); | |
138 | return ttl; | |
139 | } | |
140 | ||
141 | /* | |
142 | * Add an ip header to a skbuff and send it out. | |
143 | * | |
144 | */ | |
145 | int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk, | |
146 | __be32 saddr, __be32 daddr, struct ip_options_rcu *opt, | |
147 | u8 tos) | |
148 | { | |
149 | struct inet_sock *inet = inet_sk(sk); | |
150 | struct rtable *rt = skb_rtable(skb); | |
151 | struct net *net = sock_net(sk); | |
152 | struct iphdr *iph; | |
153 | ||
154 | /* Build the IP header. */ | |
155 | skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); | |
156 | skb_reset_network_header(skb); | |
157 | iph = ip_hdr(skb); | |
158 | iph->version = 4; | |
159 | iph->ihl = 5; | |
160 | iph->tos = tos; | |
161 | iph->ttl = ip_select_ttl(inet, &rt->dst); | |
162 | iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr); | |
163 | iph->saddr = saddr; | |
164 | iph->protocol = sk->sk_protocol; | |
165 | if (ip_dont_fragment(sk, &rt->dst)) { | |
166 | iph->frag_off = htons(IP_DF); | |
167 | iph->id = 0; | |
168 | } else { | |
169 | iph->frag_off = 0; | |
170 | __ip_select_ident(net, iph, 1); | |
171 | } | |
172 | ||
173 | if (opt && opt->opt.optlen) { | |
174 | iph->ihl += opt->opt.optlen>>2; | |
175 | ip_options_build(skb, &opt->opt, daddr, rt, 0); | |
176 | } | |
177 | ||
178 | skb->priority = sk->sk_priority; | |
179 | if (!skb->mark) | |
180 | skb->mark = sk->sk_mark; | |
181 | ||
182 | /* Send it out. */ | |
183 | return ip_local_out(net, skb->sk, skb); | |
184 | } | |
185 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); | |
186 | ||
187 | static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) | |
188 | { | |
189 | struct dst_entry *dst = skb_dst(skb); | |
190 | struct rtable *rt = (struct rtable *)dst; | |
191 | struct net_device *dev = dst->dev; | |
192 | unsigned int hh_len = LL_RESERVED_SPACE(dev); | |
193 | struct neighbour *neigh; | |
194 | bool is_v6gw = false; | |
195 | ||
196 | if (rt->rt_type == RTN_MULTICAST) { | |
197 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len); | |
198 | } else if (rt->rt_type == RTN_BROADCAST) | |
199 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len); | |
200 | ||
201 | /* Be paranoid, rather than too clever. */ | |
202 | if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { | |
203 | struct sk_buff *skb2; | |
204 | ||
205 | skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); | |
206 | if (!skb2) { | |
207 | kfree_skb(skb); | |
208 | return -ENOMEM; | |
209 | } | |
210 | if (skb->sk) | |
211 | skb_set_owner_w(skb2, skb->sk); | |
212 | consume_skb(skb); | |
213 | skb = skb2; | |
214 | } | |
215 | ||
216 | if (lwtunnel_xmit_redirect(dst->lwtstate)) { | |
217 | int res = lwtunnel_xmit(skb); | |
218 | ||
219 | if (res < 0 || res == LWTUNNEL_XMIT_DONE) | |
220 | return res; | |
221 | } | |
222 | ||
223 | rcu_read_lock_bh(); | |
224 | neigh = ip_neigh_for_gw(rt, skb, &is_v6gw); | |
225 | if (!IS_ERR(neigh)) { | |
226 | int res; | |
227 | ||
228 | sock_confirm_neigh(skb, neigh); | |
229 | /* if crossing protocols, can not use the cached header */ | |
230 | res = neigh_output(neigh, skb, is_v6gw); | |
231 | rcu_read_unlock_bh(); | |
232 | return res; | |
233 | } | |
234 | rcu_read_unlock_bh(); | |
235 | ||
236 | net_dbg_ratelimited("%s: No header cache and no neighbour!\n", | |
237 | __func__); | |
238 | kfree_skb(skb); | |
239 | return -EINVAL; | |
240 | } | |
241 | ||
242 | static int ip_finish_output_gso(struct net *net, struct sock *sk, | |
243 | struct sk_buff *skb, unsigned int mtu) | |
244 | { | |
245 | struct sk_buff *segs, *nskb; | |
246 | netdev_features_t features; | |
247 | int ret = 0; | |
248 | ||
249 | /* common case: seglen is <= mtu | |
250 | */ | |
251 | if (skb_gso_validate_network_len(skb, mtu)) | |
252 | return ip_finish_output2(net, sk, skb); | |
253 | ||
254 | /* Slowpath - GSO segment length exceeds the egress MTU. | |
255 | * | |
256 | * This can happen in several cases: | |
257 | * - Forwarding of a TCP GRO skb, when DF flag is not set. | |
258 | * - Forwarding of an skb that arrived on a virtualization interface | |
259 | * (virtio-net/vhost/tap) with TSO/GSO size set by other network | |
260 | * stack. | |
261 | * - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an | |
262 | * interface with a smaller MTU. | |
263 | * - Arriving GRO skb (or GSO skb in a virtualized environment) that is | |
264 | * bridged to a NETIF_F_TSO tunnel stacked over an interface with an | |
265 | * insufficent MTU. | |
266 | */ | |
267 | features = netif_skb_features(skb); | |
268 | BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET); | |
269 | segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); | |
270 | if (IS_ERR_OR_NULL(segs)) { | |
271 | kfree_skb(skb); | |
272 | return -ENOMEM; | |
273 | } | |
274 | ||
275 | consume_skb(skb); | |
276 | ||
277 | skb_list_walk_safe(segs, segs, nskb) { | |
278 | int err; | |
279 | ||
280 | skb_mark_not_on_list(segs); | |
281 | err = ip_fragment(net, sk, segs, mtu, ip_finish_output2); | |
282 | ||
283 | if (err && ret == 0) | |
284 | ret = err; | |
285 | } | |
286 | ||
287 | return ret; | |
288 | } | |
289 | ||
290 | static int __ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) | |
291 | { | |
292 | unsigned int mtu; | |
293 | ||
294 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) | |
295 | /* Policy lookup after SNAT yielded a new policy */ | |
296 | if (skb_dst(skb)->xfrm) { | |
297 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
298 | return dst_output(net, sk, skb); | |
299 | } | |
300 | #endif | |
301 | mtu = ip_skb_dst_mtu(sk, skb); | |
302 | if (skb_is_gso(skb)) | |
303 | return ip_finish_output_gso(net, sk, skb, mtu); | |
304 | ||
305 | if (skb->len > mtu || (IPCB(skb)->flags & IPSKB_FRAG_PMTU)) | |
306 | return ip_fragment(net, sk, skb, mtu, ip_finish_output2); | |
307 | ||
308 | return ip_finish_output2(net, sk, skb); | |
309 | } | |
310 | ||
311 | static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) | |
312 | { | |
313 | int ret; | |
314 | ||
315 | ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); | |
316 | switch (ret) { | |
317 | case NET_XMIT_SUCCESS: | |
318 | return __ip_finish_output(net, sk, skb); | |
319 | case NET_XMIT_CN: | |
320 | return __ip_finish_output(net, sk, skb) ? : ret; | |
321 | default: | |
322 | kfree_skb(skb); | |
323 | return ret; | |
324 | } | |
325 | } | |
326 | ||
327 | static int ip_mc_finish_output(struct net *net, struct sock *sk, | |
328 | struct sk_buff *skb) | |
329 | { | |
330 | struct rtable *new_rt; | |
331 | bool do_cn = false; | |
332 | int ret, err; | |
333 | ||
334 | ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); | |
335 | switch (ret) { | |
336 | case NET_XMIT_CN: | |
337 | do_cn = true; | |
338 | fallthrough; | |
339 | case NET_XMIT_SUCCESS: | |
340 | break; | |
341 | default: | |
342 | kfree_skb(skb); | |
343 | return ret; | |
344 | } | |
345 | ||
346 | /* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting | |
347 | * this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten, | |
348 | * see ipv4_pktinfo_prepare(). | |
349 | */ | |
350 | new_rt = rt_dst_clone(net->loopback_dev, skb_rtable(skb)); | |
351 | if (new_rt) { | |
352 | new_rt->rt_iif = 0; | |
353 | skb_dst_drop(skb); | |
354 | skb_dst_set(skb, &new_rt->dst); | |
355 | } | |
356 | ||
357 | err = dev_loopback_xmit(net, sk, skb); | |
358 | return (do_cn && err) ? ret : err; | |
359 | } | |
360 | ||
361 | int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb) | |
362 | { | |
363 | struct rtable *rt = skb_rtable(skb); | |
364 | struct net_device *dev = rt->dst.dev; | |
365 | ||
366 | /* | |
367 | * If the indicated interface is up and running, send the packet. | |
368 | */ | |
369 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); | |
370 | ||
371 | skb->dev = dev; | |
372 | skb->protocol = htons(ETH_P_IP); | |
373 | ||
374 | /* | |
375 | * Multicasts are looped back for other local users | |
376 | */ | |
377 | ||
378 | if (rt->rt_flags&RTCF_MULTICAST) { | |
379 | if (sk_mc_loop(sk) | |
380 | #ifdef CONFIG_IP_MROUTE | |
381 | /* Small optimization: do not loopback not local frames, | |
382 | which returned after forwarding; they will be dropped | |
383 | by ip_mr_input in any case. | |
384 | Note, that local frames are looped back to be delivered | |
385 | to local recipients. | |
386 | ||
387 | This check is duplicated in ip_mr_input at the moment. | |
388 | */ | |
389 | && | |
390 | ((rt->rt_flags & RTCF_LOCAL) || | |
391 | !(IPCB(skb)->flags & IPSKB_FORWARDED)) | |
392 | #endif | |
393 | ) { | |
394 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
395 | if (newskb) | |
396 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, | |
397 | net, sk, newskb, NULL, newskb->dev, | |
398 | ip_mc_finish_output); | |
399 | } | |
400 | ||
401 | /* Multicasts with ttl 0 must not go beyond the host */ | |
402 | ||
403 | if (ip_hdr(skb)->ttl == 0) { | |
404 | kfree_skb(skb); | |
405 | return 0; | |
406 | } | |
407 | } | |
408 | ||
409 | if (rt->rt_flags&RTCF_BROADCAST) { | |
410 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); | |
411 | if (newskb) | |
412 | NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, | |
413 | net, sk, newskb, NULL, newskb->dev, | |
414 | ip_mc_finish_output); | |
415 | } | |
416 | ||
417 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, | |
418 | net, sk, skb, NULL, skb->dev, | |
419 | ip_finish_output, | |
420 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
421 | } | |
422 | ||
423 | int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb) | |
424 | { | |
425 | struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev; | |
426 | ||
427 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); | |
428 | ||
429 | skb->dev = dev; | |
430 | skb->protocol = htons(ETH_P_IP); | |
431 | ||
432 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, | |
433 | net, sk, skb, indev, dev, | |
434 | ip_finish_output, | |
435 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
436 | } | |
437 | ||
438 | /* | |
439 | * copy saddr and daddr, possibly using 64bit load/stores | |
440 | * Equivalent to : | |
441 | * iph->saddr = fl4->saddr; | |
442 | * iph->daddr = fl4->daddr; | |
443 | */ | |
444 | static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4) | |
445 | { | |
446 | BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) != | |
447 | offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr)); | |
448 | memcpy(&iph->saddr, &fl4->saddr, | |
449 | sizeof(fl4->saddr) + sizeof(fl4->daddr)); | |
450 | } | |
451 | ||
452 | /* Note: skb->sk can be different from sk, in case of tunnels */ | |
453 | int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, | |
454 | __u8 tos) | |
455 | { | |
456 | struct inet_sock *inet = inet_sk(sk); | |
457 | struct net *net = sock_net(sk); | |
458 | struct ip_options_rcu *inet_opt; | |
459 | struct flowi4 *fl4; | |
460 | struct rtable *rt; | |
461 | struct iphdr *iph; | |
462 | int res; | |
463 | ||
464 | /* Skip all of this if the packet is already routed, | |
465 | * f.e. by something like SCTP. | |
466 | */ | |
467 | rcu_read_lock(); | |
468 | inet_opt = rcu_dereference(inet->inet_opt); | |
469 | fl4 = &fl->u.ip4; | |
470 | rt = skb_rtable(skb); | |
471 | if (rt) | |
472 | goto packet_routed; | |
473 | ||
474 | /* Make sure we can route this packet. */ | |
475 | rt = (struct rtable *)__sk_dst_check(sk, 0); | |
476 | if (!rt) { | |
477 | __be32 daddr; | |
478 | ||
479 | /* Use correct destination address if we have options. */ | |
480 | daddr = inet->inet_daddr; | |
481 | if (inet_opt && inet_opt->opt.srr) | |
482 | daddr = inet_opt->opt.faddr; | |
483 | ||
484 | /* If this fails, retransmit mechanism of transport layer will | |
485 | * keep trying until route appears or the connection times | |
486 | * itself out. | |
487 | */ | |
488 | rt = ip_route_output_ports(net, fl4, sk, | |
489 | daddr, inet->inet_saddr, | |
490 | inet->inet_dport, | |
491 | inet->inet_sport, | |
492 | sk->sk_protocol, | |
493 | RT_CONN_FLAGS_TOS(sk, tos), | |
494 | sk->sk_bound_dev_if); | |
495 | if (IS_ERR(rt)) | |
496 | goto no_route; | |
497 | sk_setup_caps(sk, &rt->dst); | |
498 | } | |
499 | skb_dst_set_noref(skb, &rt->dst); | |
500 | ||
501 | packet_routed: | |
502 | if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway) | |
503 | goto no_route; | |
504 | ||
505 | /* OK, we know where to send it, allocate and build IP header. */ | |
506 | skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0)); | |
507 | skb_reset_network_header(skb); | |
508 | iph = ip_hdr(skb); | |
509 | *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (tos & 0xff)); | |
510 | if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df) | |
511 | iph->frag_off = htons(IP_DF); | |
512 | else | |
513 | iph->frag_off = 0; | |
514 | iph->ttl = ip_select_ttl(inet, &rt->dst); | |
515 | iph->protocol = sk->sk_protocol; | |
516 | ip_copy_addrs(iph, fl4); | |
517 | ||
518 | /* Transport layer set skb->h.foo itself. */ | |
519 | ||
520 | if (inet_opt && inet_opt->opt.optlen) { | |
521 | iph->ihl += inet_opt->opt.optlen >> 2; | |
522 | ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0); | |
523 | } | |
524 | ||
525 | ip_select_ident_segs(net, skb, sk, | |
526 | skb_shinfo(skb)->gso_segs ?: 1); | |
527 | ||
528 | /* TODO : should we use skb->sk here instead of sk ? */ | |
529 | skb->priority = sk->sk_priority; | |
530 | skb->mark = sk->sk_mark; | |
531 | ||
532 | res = ip_local_out(net, sk, skb); | |
533 | rcu_read_unlock(); | |
534 | return res; | |
535 | ||
536 | no_route: | |
537 | rcu_read_unlock(); | |
538 | IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); | |
539 | kfree_skb(skb); | |
540 | return -EHOSTUNREACH; | |
541 | } | |
542 | EXPORT_SYMBOL(__ip_queue_xmit); | |
543 | ||
544 | int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl) | |
545 | { | |
546 | return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos); | |
547 | } | |
548 | EXPORT_SYMBOL(ip_queue_xmit); | |
549 | ||
550 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) | |
551 | { | |
552 | to->pkt_type = from->pkt_type; | |
553 | to->priority = from->priority; | |
554 | to->protocol = from->protocol; | |
555 | to->skb_iif = from->skb_iif; | |
556 | skb_dst_drop(to); | |
557 | skb_dst_copy(to, from); | |
558 | to->dev = from->dev; | |
559 | to->mark = from->mark; | |
560 | ||
561 | skb_copy_hash(to, from); | |
562 | ||
563 | #ifdef CONFIG_NET_SCHED | |
564 | to->tc_index = from->tc_index; | |
565 | #endif | |
566 | nf_copy(to, from); | |
567 | skb_ext_copy(to, from); | |
568 | #if IS_ENABLED(CONFIG_IP_VS) | |
569 | to->ipvs_property = from->ipvs_property; | |
570 | #endif | |
571 | skb_copy_secmark(to, from); | |
572 | } | |
573 | ||
574 | static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, | |
575 | unsigned int mtu, | |
576 | int (*output)(struct net *, struct sock *, struct sk_buff *)) | |
577 | { | |
578 | struct iphdr *iph = ip_hdr(skb); | |
579 | ||
580 | if ((iph->frag_off & htons(IP_DF)) == 0) | |
581 | return ip_do_fragment(net, sk, skb, output); | |
582 | ||
583 | if (unlikely(!skb->ignore_df || | |
584 | (IPCB(skb)->frag_max_size && | |
585 | IPCB(skb)->frag_max_size > mtu))) { | |
586 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); | |
587 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, | |
588 | htonl(mtu)); | |
589 | kfree_skb(skb); | |
590 | return -EMSGSIZE; | |
591 | } | |
592 | ||
593 | return ip_do_fragment(net, sk, skb, output); | |
594 | } | |
595 | ||
596 | void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph, | |
597 | unsigned int hlen, struct ip_fraglist_iter *iter) | |
598 | { | |
599 | unsigned int first_len = skb_pagelen(skb); | |
600 | ||
601 | iter->frag = skb_shinfo(skb)->frag_list; | |
602 | skb_frag_list_init(skb); | |
603 | ||
604 | iter->offset = 0; | |
605 | iter->iph = iph; | |
606 | iter->hlen = hlen; | |
607 | ||
608 | skb->data_len = first_len - skb_headlen(skb); | |
609 | skb->len = first_len; | |
610 | iph->tot_len = htons(first_len); | |
611 | iph->frag_off = htons(IP_MF); | |
612 | ip_send_check(iph); | |
613 | } | |
614 | EXPORT_SYMBOL(ip_fraglist_init); | |
615 | ||
616 | static void ip_fraglist_ipcb_prepare(struct sk_buff *skb, | |
617 | struct ip_fraglist_iter *iter) | |
618 | { | |
619 | struct sk_buff *to = iter->frag; | |
620 | ||
621 | /* Copy the flags to each fragment. */ | |
622 | IPCB(to)->flags = IPCB(skb)->flags; | |
623 | ||
624 | if (iter->offset == 0) | |
625 | ip_options_fragment(to); | |
626 | } | |
627 | ||
628 | void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter) | |
629 | { | |
630 | unsigned int hlen = iter->hlen; | |
631 | struct iphdr *iph = iter->iph; | |
632 | struct sk_buff *frag; | |
633 | ||
634 | frag = iter->frag; | |
635 | frag->ip_summed = CHECKSUM_NONE; | |
636 | skb_reset_transport_header(frag); | |
637 | __skb_push(frag, hlen); | |
638 | skb_reset_network_header(frag); | |
639 | memcpy(skb_network_header(frag), iph, hlen); | |
640 | iter->iph = ip_hdr(frag); | |
641 | iph = iter->iph; | |
642 | iph->tot_len = htons(frag->len); | |
643 | ip_copy_metadata(frag, skb); | |
644 | iter->offset += skb->len - hlen; | |
645 | iph->frag_off = htons(iter->offset >> 3); | |
646 | if (frag->next) | |
647 | iph->frag_off |= htons(IP_MF); | |
648 | /* Ready, complete checksum */ | |
649 | ip_send_check(iph); | |
650 | } | |
651 | EXPORT_SYMBOL(ip_fraglist_prepare); | |
652 | ||
653 | void ip_frag_init(struct sk_buff *skb, unsigned int hlen, | |
654 | unsigned int ll_rs, unsigned int mtu, bool DF, | |
655 | struct ip_frag_state *state) | |
656 | { | |
657 | struct iphdr *iph = ip_hdr(skb); | |
658 | ||
659 | state->DF = DF; | |
660 | state->hlen = hlen; | |
661 | state->ll_rs = ll_rs; | |
662 | state->mtu = mtu; | |
663 | ||
664 | state->left = skb->len - hlen; /* Space per frame */ | |
665 | state->ptr = hlen; /* Where to start from */ | |
666 | ||
667 | state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; | |
668 | state->not_last_frag = iph->frag_off & htons(IP_MF); | |
669 | } | |
670 | EXPORT_SYMBOL(ip_frag_init); | |
671 | ||
672 | static void ip_frag_ipcb(struct sk_buff *from, struct sk_buff *to, | |
673 | bool first_frag, struct ip_frag_state *state) | |
674 | { | |
675 | /* Copy the flags to each fragment. */ | |
676 | IPCB(to)->flags = IPCB(from)->flags; | |
677 | ||
678 | /* ANK: dirty, but effective trick. Upgrade options only if | |
679 | * the segment to be fragmented was THE FIRST (otherwise, | |
680 | * options are already fixed) and make it ONCE | |
681 | * on the initial skb, so that all the following fragments | |
682 | * will inherit fixed options. | |
683 | */ | |
684 | if (first_frag) | |
685 | ip_options_fragment(from); | |
686 | } | |
687 | ||
688 | struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state) | |
689 | { | |
690 | unsigned int len = state->left; | |
691 | struct sk_buff *skb2; | |
692 | struct iphdr *iph; | |
693 | ||
694 | len = state->left; | |
695 | /* IF: it doesn't fit, use 'mtu' - the data space left */ | |
696 | if (len > state->mtu) | |
697 | len = state->mtu; | |
698 | /* IF: we are not sending up to and including the packet end | |
699 | then align the next start on an eight byte boundary */ | |
700 | if (len < state->left) { | |
701 | len &= ~7; | |
702 | } | |
703 | ||
704 | /* Allocate buffer */ | |
705 | skb2 = alloc_skb(len + state->hlen + state->ll_rs, GFP_ATOMIC); | |
706 | if (!skb2) | |
707 | return ERR_PTR(-ENOMEM); | |
708 | ||
709 | /* | |
710 | * Set up data on packet | |
711 | */ | |
712 | ||
713 | ip_copy_metadata(skb2, skb); | |
714 | skb_reserve(skb2, state->ll_rs); | |
715 | skb_put(skb2, len + state->hlen); | |
716 | skb_reset_network_header(skb2); | |
717 | skb2->transport_header = skb2->network_header + state->hlen; | |
718 | ||
719 | /* | |
720 | * Charge the memory for the fragment to any owner | |
721 | * it might possess | |
722 | */ | |
723 | ||
724 | if (skb->sk) | |
725 | skb_set_owner_w(skb2, skb->sk); | |
726 | ||
727 | /* | |
728 | * Copy the packet header into the new buffer. | |
729 | */ | |
730 | ||
731 | skb_copy_from_linear_data(skb, skb_network_header(skb2), state->hlen); | |
732 | ||
733 | /* | |
734 | * Copy a block of the IP datagram. | |
735 | */ | |
736 | if (skb_copy_bits(skb, state->ptr, skb_transport_header(skb2), len)) | |
737 | BUG(); | |
738 | state->left -= len; | |
739 | ||
740 | /* | |
741 | * Fill in the new header fields. | |
742 | */ | |
743 | iph = ip_hdr(skb2); | |
744 | iph->frag_off = htons((state->offset >> 3)); | |
745 | if (state->DF) | |
746 | iph->frag_off |= htons(IP_DF); | |
747 | ||
748 | /* | |
749 | * Added AC : If we are fragmenting a fragment that's not the | |
750 | * last fragment then keep MF on each bit | |
751 | */ | |
752 | if (state->left > 0 || state->not_last_frag) | |
753 | iph->frag_off |= htons(IP_MF); | |
754 | state->ptr += len; | |
755 | state->offset += len; | |
756 | ||
757 | iph->tot_len = htons(len + state->hlen); | |
758 | ||
759 | ip_send_check(iph); | |
760 | ||
761 | return skb2; | |
762 | } | |
763 | EXPORT_SYMBOL(ip_frag_next); | |
764 | ||
765 | /* | |
766 | * This IP datagram is too large to be sent in one piece. Break it up into | |
767 | * smaller pieces (each of size equal to IP header plus | |
768 | * a block of the data of the original IP data part) that will yet fit in a | |
769 | * single device frame, and queue such a frame for sending. | |
770 | */ | |
771 | ||
772 | int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, | |
773 | int (*output)(struct net *, struct sock *, struct sk_buff *)) | |
774 | { | |
775 | struct iphdr *iph; | |
776 | struct sk_buff *skb2; | |
777 | struct rtable *rt = skb_rtable(skb); | |
778 | unsigned int mtu, hlen, ll_rs; | |
779 | struct ip_fraglist_iter iter; | |
780 | ktime_t tstamp = skb->tstamp; | |
781 | struct ip_frag_state state; | |
782 | int err = 0; | |
783 | ||
784 | /* for offloaded checksums cleanup checksum before fragmentation */ | |
785 | if (skb->ip_summed == CHECKSUM_PARTIAL && | |
786 | (err = skb_checksum_help(skb))) | |
787 | goto fail; | |
788 | ||
789 | /* | |
790 | * Point into the IP datagram header. | |
791 | */ | |
792 | ||
793 | iph = ip_hdr(skb); | |
794 | ||
795 | mtu = ip_skb_dst_mtu(sk, skb); | |
796 | if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu) | |
797 | mtu = IPCB(skb)->frag_max_size; | |
798 | ||
799 | /* | |
800 | * Setup starting values. | |
801 | */ | |
802 | ||
803 | hlen = iph->ihl * 4; | |
804 | mtu = mtu - hlen; /* Size of data space */ | |
805 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; | |
806 | ll_rs = LL_RESERVED_SPACE(rt->dst.dev); | |
807 | ||
808 | /* When frag_list is given, use it. First, check its validity: | |
809 | * some transformers could create wrong frag_list or break existing | |
810 | * one, it is not prohibited. In this case fall back to copying. | |
811 | * | |
812 | * LATER: this step can be merged to real generation of fragments, | |
813 | * we can switch to copy when see the first bad fragment. | |
814 | */ | |
815 | if (skb_has_frag_list(skb)) { | |
816 | struct sk_buff *frag, *frag2; | |
817 | unsigned int first_len = skb_pagelen(skb); | |
818 | ||
819 | if (first_len - hlen > mtu || | |
820 | ((first_len - hlen) & 7) || | |
821 | ip_is_fragment(iph) || | |
822 | skb_cloned(skb) || | |
823 | skb_headroom(skb) < ll_rs) | |
824 | goto slow_path; | |
825 | ||
826 | skb_walk_frags(skb, frag) { | |
827 | /* Correct geometry. */ | |
828 | if (frag->len > mtu || | |
829 | ((frag->len & 7) && frag->next) || | |
830 | skb_headroom(frag) < hlen + ll_rs) | |
831 | goto slow_path_clean; | |
832 | ||
833 | /* Partially cloned skb? */ | |
834 | if (skb_shared(frag)) | |
835 | goto slow_path_clean; | |
836 | ||
837 | BUG_ON(frag->sk); | |
838 | if (skb->sk) { | |
839 | frag->sk = skb->sk; | |
840 | frag->destructor = sock_wfree; | |
841 | } | |
842 | skb->truesize -= frag->truesize; | |
843 | } | |
844 | ||
845 | /* Everything is OK. Generate! */ | |
846 | ip_fraglist_init(skb, iph, hlen, &iter); | |
847 | ||
848 | for (;;) { | |
849 | /* Prepare header of the next frame, | |
850 | * before previous one went down. */ | |
851 | if (iter.frag) { | |
852 | ip_fraglist_ipcb_prepare(skb, &iter); | |
853 | ip_fraglist_prepare(skb, &iter); | |
854 | } | |
855 | ||
856 | skb->tstamp = tstamp; | |
857 | err = output(net, sk, skb); | |
858 | ||
859 | if (!err) | |
860 | IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); | |
861 | if (err || !iter.frag) | |
862 | break; | |
863 | ||
864 | skb = ip_fraglist_next(&iter); | |
865 | } | |
866 | ||
867 | if (err == 0) { | |
868 | IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); | |
869 | return 0; | |
870 | } | |
871 | ||
872 | kfree_skb_list(iter.frag); | |
873 | ||
874 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); | |
875 | return err; | |
876 | ||
877 | slow_path_clean: | |
878 | skb_walk_frags(skb, frag2) { | |
879 | if (frag2 == frag) | |
880 | break; | |
881 | frag2->sk = NULL; | |
882 | frag2->destructor = NULL; | |
883 | skb->truesize += frag2->truesize; | |
884 | } | |
885 | } | |
886 | ||
887 | slow_path: | |
888 | /* | |
889 | * Fragment the datagram. | |
890 | */ | |
891 | ||
892 | ip_frag_init(skb, hlen, ll_rs, mtu, IPCB(skb)->flags & IPSKB_FRAG_PMTU, | |
893 | &state); | |
894 | ||
895 | /* | |
896 | * Keep copying data until we run out. | |
897 | */ | |
898 | ||
899 | while (state.left > 0) { | |
900 | bool first_frag = (state.offset == 0); | |
901 | ||
902 | skb2 = ip_frag_next(skb, &state); | |
903 | if (IS_ERR(skb2)) { | |
904 | err = PTR_ERR(skb2); | |
905 | goto fail; | |
906 | } | |
907 | ip_frag_ipcb(skb, skb2, first_frag, &state); | |
908 | ||
909 | /* | |
910 | * Put this fragment into the sending queue. | |
911 | */ | |
912 | skb2->tstamp = tstamp; | |
913 | err = output(net, sk, skb2); | |
914 | if (err) | |
915 | goto fail; | |
916 | ||
917 | IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); | |
918 | } | |
919 | consume_skb(skb); | |
920 | IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); | |
921 | return err; | |
922 | ||
923 | fail: | |
924 | kfree_skb(skb); | |
925 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); | |
926 | return err; | |
927 | } | |
928 | EXPORT_SYMBOL(ip_do_fragment); | |
929 | ||
930 | int | |
931 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) | |
932 | { | |
933 | struct msghdr *msg = from; | |
934 | ||
935 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
936 | if (!copy_from_iter_full(to, len, &msg->msg_iter)) | |
937 | return -EFAULT; | |
938 | } else { | |
939 | __wsum csum = 0; | |
940 | if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter)) | |
941 | return -EFAULT; | |
942 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
943 | } | |
944 | return 0; | |
945 | } | |
946 | EXPORT_SYMBOL(ip_generic_getfrag); | |
947 | ||
948 | static inline __wsum | |
949 | csum_page(struct page *page, int offset, int copy) | |
950 | { | |
951 | char *kaddr; | |
952 | __wsum csum; | |
953 | kaddr = kmap(page); | |
954 | csum = csum_partial(kaddr + offset, copy, 0); | |
955 | kunmap(page); | |
956 | return csum; | |
957 | } | |
958 | ||
959 | static int __ip_append_data(struct sock *sk, | |
960 | struct flowi4 *fl4, | |
961 | struct sk_buff_head *queue, | |
962 | struct inet_cork *cork, | |
963 | struct page_frag *pfrag, | |
964 | int getfrag(void *from, char *to, int offset, | |
965 | int len, int odd, struct sk_buff *skb), | |
966 | void *from, int length, int transhdrlen, | |
967 | unsigned int flags) | |
968 | { | |
969 | struct inet_sock *inet = inet_sk(sk); | |
970 | struct ubuf_info *uarg = NULL; | |
971 | struct sk_buff *skb; | |
972 | ||
973 | struct ip_options *opt = cork->opt; | |
974 | int hh_len; | |
975 | int exthdrlen; | |
976 | int mtu; | |
977 | int copy; | |
978 | int err; | |
979 | int offset = 0; | |
980 | unsigned int maxfraglen, fragheaderlen, maxnonfragsize; | |
981 | int csummode = CHECKSUM_NONE; | |
982 | struct rtable *rt = (struct rtable *)cork->dst; | |
983 | unsigned int wmem_alloc_delta = 0; | |
984 | bool paged, extra_uref = false; | |
985 | u32 tskey = 0; | |
986 | ||
987 | skb = skb_peek_tail(queue); | |
988 | ||
989 | exthdrlen = !skb ? rt->dst.header_len : 0; | |
990 | mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize; | |
991 | paged = !!cork->gso_size; | |
992 | ||
993 | if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP && | |
994 | sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) | |
995 | tskey = sk->sk_tskey++; | |
996 | ||
997 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); | |
998 | ||
999 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1000 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1001 | maxnonfragsize = ip_sk_ignore_df(sk) ? IP_MAX_MTU : mtu; | |
1002 | ||
1003 | if (cork->length + length > maxnonfragsize - fragheaderlen) { | |
1004 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, | |
1005 | mtu - (opt ? opt->optlen : 0)); | |
1006 | return -EMSGSIZE; | |
1007 | } | |
1008 | ||
1009 | /* | |
1010 | * transhdrlen > 0 means that this is the first fragment and we wish | |
1011 | * it won't be fragmented in the future. | |
1012 | */ | |
1013 | if (transhdrlen && | |
1014 | length + fragheaderlen <= mtu && | |
1015 | rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) && | |
1016 | (!(flags & MSG_MORE) || cork->gso_size) && | |
1017 | (!exthdrlen || (rt->dst.dev->features & NETIF_F_HW_ESP_TX_CSUM))) | |
1018 | csummode = CHECKSUM_PARTIAL; | |
1019 | ||
1020 | if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) { | |
1021 | uarg = sock_zerocopy_realloc(sk, length, skb_zcopy(skb)); | |
1022 | if (!uarg) | |
1023 | return -ENOBUFS; | |
1024 | extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ | |
1025 | if (rt->dst.dev->features & NETIF_F_SG && | |
1026 | csummode == CHECKSUM_PARTIAL) { | |
1027 | paged = true; | |
1028 | } else { | |
1029 | uarg->zerocopy = 0; | |
1030 | skb_zcopy_set(skb, uarg, &extra_uref); | |
1031 | } | |
1032 | } | |
1033 | ||
1034 | cork->length += length; | |
1035 | ||
1036 | /* So, what's going on in the loop below? | |
1037 | * | |
1038 | * We use calculated fragment length to generate chained skb, | |
1039 | * each of segments is IP fragment ready for sending to network after | |
1040 | * adding appropriate IP header. | |
1041 | */ | |
1042 | ||
1043 | if (!skb) | |
1044 | goto alloc_new_skb; | |
1045 | ||
1046 | while (length > 0) { | |
1047 | /* Check if the remaining data fits into current packet. */ | |
1048 | copy = mtu - skb->len; | |
1049 | if (copy < length) | |
1050 | copy = maxfraglen - skb->len; | |
1051 | if (copy <= 0) { | |
1052 | char *data; | |
1053 | unsigned int datalen; | |
1054 | unsigned int fraglen; | |
1055 | unsigned int fraggap; | |
1056 | unsigned int alloclen; | |
1057 | unsigned int pagedlen; | |
1058 | struct sk_buff *skb_prev; | |
1059 | alloc_new_skb: | |
1060 | skb_prev = skb; | |
1061 | if (skb_prev) | |
1062 | fraggap = skb_prev->len - maxfraglen; | |
1063 | else | |
1064 | fraggap = 0; | |
1065 | ||
1066 | /* | |
1067 | * If remaining data exceeds the mtu, | |
1068 | * we know we need more fragment(s). | |
1069 | */ | |
1070 | datalen = length + fraggap; | |
1071 | if (datalen > mtu - fragheaderlen) | |
1072 | datalen = maxfraglen - fragheaderlen; | |
1073 | fraglen = datalen + fragheaderlen; | |
1074 | pagedlen = 0; | |
1075 | ||
1076 | if ((flags & MSG_MORE) && | |
1077 | !(rt->dst.dev->features&NETIF_F_SG)) | |
1078 | alloclen = mtu; | |
1079 | else if (!paged) | |
1080 | alloclen = fraglen; | |
1081 | else { | |
1082 | alloclen = min_t(int, fraglen, MAX_HEADER); | |
1083 | pagedlen = fraglen - alloclen; | |
1084 | } | |
1085 | ||
1086 | alloclen += exthdrlen; | |
1087 | ||
1088 | /* The last fragment gets additional space at tail. | |
1089 | * Note, with MSG_MORE we overallocate on fragments, | |
1090 | * because we have no idea what fragment will be | |
1091 | * the last. | |
1092 | */ | |
1093 | if (datalen == length + fraggap) | |
1094 | alloclen += rt->dst.trailer_len; | |
1095 | ||
1096 | if (transhdrlen) { | |
1097 | skb = sock_alloc_send_skb(sk, | |
1098 | alloclen + hh_len + 15, | |
1099 | (flags & MSG_DONTWAIT), &err); | |
1100 | } else { | |
1101 | skb = NULL; | |
1102 | if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= | |
1103 | 2 * sk->sk_sndbuf) | |
1104 | skb = alloc_skb(alloclen + hh_len + 15, | |
1105 | sk->sk_allocation); | |
1106 | if (unlikely(!skb)) | |
1107 | err = -ENOBUFS; | |
1108 | } | |
1109 | if (!skb) | |
1110 | goto error; | |
1111 | ||
1112 | /* | |
1113 | * Fill in the control structures | |
1114 | */ | |
1115 | skb->ip_summed = csummode; | |
1116 | skb->csum = 0; | |
1117 | skb_reserve(skb, hh_len); | |
1118 | ||
1119 | /* | |
1120 | * Find where to start putting bytes. | |
1121 | */ | |
1122 | data = skb_put(skb, fraglen + exthdrlen - pagedlen); | |
1123 | skb_set_network_header(skb, exthdrlen); | |
1124 | skb->transport_header = (skb->network_header + | |
1125 | fragheaderlen); | |
1126 | data += fragheaderlen + exthdrlen; | |
1127 | ||
1128 | if (fraggap) { | |
1129 | skb->csum = skb_copy_and_csum_bits( | |
1130 | skb_prev, maxfraglen, | |
1131 | data + transhdrlen, fraggap); | |
1132 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1133 | skb->csum); | |
1134 | data += fraggap; | |
1135 | pskb_trim_unique(skb_prev, maxfraglen); | |
1136 | } | |
1137 | ||
1138 | copy = datalen - transhdrlen - fraggap - pagedlen; | |
1139 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { | |
1140 | err = -EFAULT; | |
1141 | kfree_skb(skb); | |
1142 | goto error; | |
1143 | } | |
1144 | ||
1145 | offset += copy; | |
1146 | length -= copy + transhdrlen; | |
1147 | transhdrlen = 0; | |
1148 | exthdrlen = 0; | |
1149 | csummode = CHECKSUM_NONE; | |
1150 | ||
1151 | /* only the initial fragment is time stamped */ | |
1152 | skb_shinfo(skb)->tx_flags = cork->tx_flags; | |
1153 | cork->tx_flags = 0; | |
1154 | skb_shinfo(skb)->tskey = tskey; | |
1155 | tskey = 0; | |
1156 | skb_zcopy_set(skb, uarg, &extra_uref); | |
1157 | ||
1158 | if ((flags & MSG_CONFIRM) && !skb_prev) | |
1159 | skb_set_dst_pending_confirm(skb, 1); | |
1160 | ||
1161 | /* | |
1162 | * Put the packet on the pending queue. | |
1163 | */ | |
1164 | if (!skb->destructor) { | |
1165 | skb->destructor = sock_wfree; | |
1166 | skb->sk = sk; | |
1167 | wmem_alloc_delta += skb->truesize; | |
1168 | } | |
1169 | __skb_queue_tail(queue, skb); | |
1170 | continue; | |
1171 | } | |
1172 | ||
1173 | if (copy > length) | |
1174 | copy = length; | |
1175 | ||
1176 | if (!(rt->dst.dev->features&NETIF_F_SG) && | |
1177 | skb_tailroom(skb) >= copy) { | |
1178 | unsigned int off; | |
1179 | ||
1180 | off = skb->len; | |
1181 | if (getfrag(from, skb_put(skb, copy), | |
1182 | offset, copy, off, skb) < 0) { | |
1183 | __skb_trim(skb, off); | |
1184 | err = -EFAULT; | |
1185 | goto error; | |
1186 | } | |
1187 | } else if (!uarg || !uarg->zerocopy) { | |
1188 | int i = skb_shinfo(skb)->nr_frags; | |
1189 | ||
1190 | err = -ENOMEM; | |
1191 | if (!sk_page_frag_refill(sk, pfrag)) | |
1192 | goto error; | |
1193 | ||
1194 | if (!skb_can_coalesce(skb, i, pfrag->page, | |
1195 | pfrag->offset)) { | |
1196 | err = -EMSGSIZE; | |
1197 | if (i == MAX_SKB_FRAGS) | |
1198 | goto error; | |
1199 | ||
1200 | __skb_fill_page_desc(skb, i, pfrag->page, | |
1201 | pfrag->offset, 0); | |
1202 | skb_shinfo(skb)->nr_frags = ++i; | |
1203 | get_page(pfrag->page); | |
1204 | } | |
1205 | copy = min_t(int, copy, pfrag->size - pfrag->offset); | |
1206 | if (getfrag(from, | |
1207 | page_address(pfrag->page) + pfrag->offset, | |
1208 | offset, copy, skb->len, skb) < 0) | |
1209 | goto error_efault; | |
1210 | ||
1211 | pfrag->offset += copy; | |
1212 | skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); | |
1213 | skb->len += copy; | |
1214 | skb->data_len += copy; | |
1215 | skb->truesize += copy; | |
1216 | wmem_alloc_delta += copy; | |
1217 | } else { | |
1218 | err = skb_zerocopy_iter_dgram(skb, from, copy); | |
1219 | if (err < 0) | |
1220 | goto error; | |
1221 | } | |
1222 | offset += copy; | |
1223 | length -= copy; | |
1224 | } | |
1225 | ||
1226 | if (wmem_alloc_delta) | |
1227 | refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); | |
1228 | return 0; | |
1229 | ||
1230 | error_efault: | |
1231 | err = -EFAULT; | |
1232 | error: | |
1233 | if (uarg) | |
1234 | sock_zerocopy_put_abort(uarg, extra_uref); | |
1235 | cork->length -= length; | |
1236 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1237 | refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); | |
1238 | return err; | |
1239 | } | |
1240 | ||
1241 | static int ip_setup_cork(struct sock *sk, struct inet_cork *cork, | |
1242 | struct ipcm_cookie *ipc, struct rtable **rtp) | |
1243 | { | |
1244 | struct ip_options_rcu *opt; | |
1245 | struct rtable *rt; | |
1246 | ||
1247 | rt = *rtp; | |
1248 | if (unlikely(!rt)) | |
1249 | return -EFAULT; | |
1250 | ||
1251 | /* | |
1252 | * setup for corking. | |
1253 | */ | |
1254 | opt = ipc->opt; | |
1255 | if (opt) { | |
1256 | if (!cork->opt) { | |
1257 | cork->opt = kmalloc(sizeof(struct ip_options) + 40, | |
1258 | sk->sk_allocation); | |
1259 | if (unlikely(!cork->opt)) | |
1260 | return -ENOBUFS; | |
1261 | } | |
1262 | memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen); | |
1263 | cork->flags |= IPCORK_OPT; | |
1264 | cork->addr = ipc->addr; | |
1265 | } | |
1266 | ||
1267 | cork->fragsize = ip_sk_use_pmtu(sk) ? | |
1268 | dst_mtu(&rt->dst) : READ_ONCE(rt->dst.dev->mtu); | |
1269 | ||
1270 | if (!inetdev_valid_mtu(cork->fragsize)) | |
1271 | return -ENETUNREACH; | |
1272 | ||
1273 | cork->gso_size = ipc->gso_size; | |
1274 | ||
1275 | cork->dst = &rt->dst; | |
1276 | /* We stole this route, caller should not release it. */ | |
1277 | *rtp = NULL; | |
1278 | ||
1279 | cork->length = 0; | |
1280 | cork->ttl = ipc->ttl; | |
1281 | cork->tos = ipc->tos; | |
1282 | cork->mark = ipc->sockc.mark; | |
1283 | cork->priority = ipc->priority; | |
1284 | cork->transmit_time = ipc->sockc.transmit_time; | |
1285 | cork->tx_flags = 0; | |
1286 | sock_tx_timestamp(sk, ipc->sockc.tsflags, &cork->tx_flags); | |
1287 | ||
1288 | return 0; | |
1289 | } | |
1290 | ||
1291 | /* | |
1292 | * ip_append_data() and ip_append_page() can make one large IP datagram | |
1293 | * from many pieces of data. Each pieces will be holded on the socket | |
1294 | * until ip_push_pending_frames() is called. Each piece can be a page | |
1295 | * or non-page data. | |
1296 | * | |
1297 | * Not only UDP, other transport protocols - e.g. raw sockets - can use | |
1298 | * this interface potentially. | |
1299 | * | |
1300 | * LATER: length must be adjusted by pad at tail, when it is required. | |
1301 | */ | |
1302 | int ip_append_data(struct sock *sk, struct flowi4 *fl4, | |
1303 | int getfrag(void *from, char *to, int offset, int len, | |
1304 | int odd, struct sk_buff *skb), | |
1305 | void *from, int length, int transhdrlen, | |
1306 | struct ipcm_cookie *ipc, struct rtable **rtp, | |
1307 | unsigned int flags) | |
1308 | { | |
1309 | struct inet_sock *inet = inet_sk(sk); | |
1310 | int err; | |
1311 | ||
1312 | if (flags&MSG_PROBE) | |
1313 | return 0; | |
1314 | ||
1315 | if (skb_queue_empty(&sk->sk_write_queue)) { | |
1316 | err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp); | |
1317 | if (err) | |
1318 | return err; | |
1319 | } else { | |
1320 | transhdrlen = 0; | |
1321 | } | |
1322 | ||
1323 | return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base, | |
1324 | sk_page_frag(sk), getfrag, | |
1325 | from, length, transhdrlen, flags); | |
1326 | } | |
1327 | ||
1328 | ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, | |
1329 | int offset, size_t size, int flags) | |
1330 | { | |
1331 | struct inet_sock *inet = inet_sk(sk); | |
1332 | struct sk_buff *skb; | |
1333 | struct rtable *rt; | |
1334 | struct ip_options *opt = NULL; | |
1335 | struct inet_cork *cork; | |
1336 | int hh_len; | |
1337 | int mtu; | |
1338 | int len; | |
1339 | int err; | |
1340 | unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize; | |
1341 | ||
1342 | if (inet->hdrincl) | |
1343 | return -EPERM; | |
1344 | ||
1345 | if (flags&MSG_PROBE) | |
1346 | return 0; | |
1347 | ||
1348 | if (skb_queue_empty(&sk->sk_write_queue)) | |
1349 | return -EINVAL; | |
1350 | ||
1351 | cork = &inet->cork.base; | |
1352 | rt = (struct rtable *)cork->dst; | |
1353 | if (cork->flags & IPCORK_OPT) | |
1354 | opt = cork->opt; | |
1355 | ||
1356 | if (!(rt->dst.dev->features & NETIF_F_SG)) | |
1357 | return -EOPNOTSUPP; | |
1358 | ||
1359 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); | |
1360 | mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize; | |
1361 | ||
1362 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); | |
1363 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; | |
1364 | maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu; | |
1365 | ||
1366 | if (cork->length + size > maxnonfragsize - fragheaderlen) { | |
1367 | ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, | |
1368 | mtu - (opt ? opt->optlen : 0)); | |
1369 | return -EMSGSIZE; | |
1370 | } | |
1371 | ||
1372 | skb = skb_peek_tail(&sk->sk_write_queue); | |
1373 | if (!skb) | |
1374 | return -EINVAL; | |
1375 | ||
1376 | cork->length += size; | |
1377 | ||
1378 | while (size > 0) { | |
1379 | /* Check if the remaining data fits into current packet. */ | |
1380 | len = mtu - skb->len; | |
1381 | if (len < size) | |
1382 | len = maxfraglen - skb->len; | |
1383 | ||
1384 | if (len <= 0) { | |
1385 | struct sk_buff *skb_prev; | |
1386 | int alloclen; | |
1387 | ||
1388 | skb_prev = skb; | |
1389 | fraggap = skb_prev->len - maxfraglen; | |
1390 | ||
1391 | alloclen = fragheaderlen + hh_len + fraggap + 15; | |
1392 | skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); | |
1393 | if (unlikely(!skb)) { | |
1394 | err = -ENOBUFS; | |
1395 | goto error; | |
1396 | } | |
1397 | ||
1398 | /* | |
1399 | * Fill in the control structures | |
1400 | */ | |
1401 | skb->ip_summed = CHECKSUM_NONE; | |
1402 | skb->csum = 0; | |
1403 | skb_reserve(skb, hh_len); | |
1404 | ||
1405 | /* | |
1406 | * Find where to start putting bytes. | |
1407 | */ | |
1408 | skb_put(skb, fragheaderlen + fraggap); | |
1409 | skb_reset_network_header(skb); | |
1410 | skb->transport_header = (skb->network_header + | |
1411 | fragheaderlen); | |
1412 | if (fraggap) { | |
1413 | skb->csum = skb_copy_and_csum_bits(skb_prev, | |
1414 | maxfraglen, | |
1415 | skb_transport_header(skb), | |
1416 | fraggap); | |
1417 | skb_prev->csum = csum_sub(skb_prev->csum, | |
1418 | skb->csum); | |
1419 | pskb_trim_unique(skb_prev, maxfraglen); | |
1420 | } | |
1421 | ||
1422 | /* | |
1423 | * Put the packet on the pending queue. | |
1424 | */ | |
1425 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1426 | continue; | |
1427 | } | |
1428 | ||
1429 | if (len > size) | |
1430 | len = size; | |
1431 | ||
1432 | if (skb_append_pagefrags(skb, page, offset, len)) { | |
1433 | err = -EMSGSIZE; | |
1434 | goto error; | |
1435 | } | |
1436 | ||
1437 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1438 | __wsum csum; | |
1439 | csum = csum_page(page, offset, len); | |
1440 | skb->csum = csum_block_add(skb->csum, csum, skb->len); | |
1441 | } | |
1442 | ||
1443 | skb->len += len; | |
1444 | skb->data_len += len; | |
1445 | skb->truesize += len; | |
1446 | refcount_add(len, &sk->sk_wmem_alloc); | |
1447 | offset += len; | |
1448 | size -= len; | |
1449 | } | |
1450 | return 0; | |
1451 | ||
1452 | error: | |
1453 | cork->length -= size; | |
1454 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); | |
1455 | return err; | |
1456 | } | |
1457 | ||
1458 | static void ip_cork_release(struct inet_cork *cork) | |
1459 | { | |
1460 | cork->flags &= ~IPCORK_OPT; | |
1461 | kfree(cork->opt); | |
1462 | cork->opt = NULL; | |
1463 | dst_release(cork->dst); | |
1464 | cork->dst = NULL; | |
1465 | } | |
1466 | ||
1467 | /* | |
1468 | * Combined all pending IP fragments on the socket as one IP datagram | |
1469 | * and push them out. | |
1470 | */ | |
1471 | struct sk_buff *__ip_make_skb(struct sock *sk, | |
1472 | struct flowi4 *fl4, | |
1473 | struct sk_buff_head *queue, | |
1474 | struct inet_cork *cork) | |
1475 | { | |
1476 | struct sk_buff *skb, *tmp_skb; | |
1477 | struct sk_buff **tail_skb; | |
1478 | struct inet_sock *inet = inet_sk(sk); | |
1479 | struct net *net = sock_net(sk); | |
1480 | struct ip_options *opt = NULL; | |
1481 | struct rtable *rt = (struct rtable *)cork->dst; | |
1482 | struct iphdr *iph; | |
1483 | __be16 df = 0; | |
1484 | __u8 ttl; | |
1485 | ||
1486 | skb = __skb_dequeue(queue); | |
1487 | if (!skb) | |
1488 | goto out; | |
1489 | tail_skb = &(skb_shinfo(skb)->frag_list); | |
1490 | ||
1491 | /* move skb->data to ip header from ext header */ | |
1492 | if (skb->data < skb_network_header(skb)) | |
1493 | __skb_pull(skb, skb_network_offset(skb)); | |
1494 | while ((tmp_skb = __skb_dequeue(queue)) != NULL) { | |
1495 | __skb_pull(tmp_skb, skb_network_header_len(skb)); | |
1496 | *tail_skb = tmp_skb; | |
1497 | tail_skb = &(tmp_skb->next); | |
1498 | skb->len += tmp_skb->len; | |
1499 | skb->data_len += tmp_skb->len; | |
1500 | skb->truesize += tmp_skb->truesize; | |
1501 | tmp_skb->destructor = NULL; | |
1502 | tmp_skb->sk = NULL; | |
1503 | } | |
1504 | ||
1505 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow | |
1506 | * to fragment the frame generated here. No matter, what transforms | |
1507 | * how transforms change size of the packet, it will come out. | |
1508 | */ | |
1509 | skb->ignore_df = ip_sk_ignore_df(sk); | |
1510 | ||
1511 | /* DF bit is set when we want to see DF on outgoing frames. | |
1512 | * If ignore_df is set too, we still allow to fragment this frame | |
1513 | * locally. */ | |
1514 | if (inet->pmtudisc == IP_PMTUDISC_DO || | |
1515 | inet->pmtudisc == IP_PMTUDISC_PROBE || | |
1516 | (skb->len <= dst_mtu(&rt->dst) && | |
1517 | ip_dont_fragment(sk, &rt->dst))) | |
1518 | df = htons(IP_DF); | |
1519 | ||
1520 | if (cork->flags & IPCORK_OPT) | |
1521 | opt = cork->opt; | |
1522 | ||
1523 | if (cork->ttl != 0) | |
1524 | ttl = cork->ttl; | |
1525 | else if (rt->rt_type == RTN_MULTICAST) | |
1526 | ttl = inet->mc_ttl; | |
1527 | else | |
1528 | ttl = ip_select_ttl(inet, &rt->dst); | |
1529 | ||
1530 | iph = ip_hdr(skb); | |
1531 | iph->version = 4; | |
1532 | iph->ihl = 5; | |
1533 | iph->tos = (cork->tos != -1) ? cork->tos : inet->tos; | |
1534 | iph->frag_off = df; | |
1535 | iph->ttl = ttl; | |
1536 | iph->protocol = sk->sk_protocol; | |
1537 | ip_copy_addrs(iph, fl4); | |
1538 | ip_select_ident(net, skb, sk); | |
1539 | ||
1540 | if (opt) { | |
1541 | iph->ihl += opt->optlen >> 2; | |
1542 | ip_options_build(skb, opt, cork->addr, rt, 0); | |
1543 | } | |
1544 | ||
1545 | skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority; | |
1546 | skb->mark = cork->mark; | |
1547 | skb->tstamp = cork->transmit_time; | |
1548 | /* | |
1549 | * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec | |
1550 | * on dst refcount | |
1551 | */ | |
1552 | cork->dst = NULL; | |
1553 | skb_dst_set(skb, &rt->dst); | |
1554 | ||
1555 | if (iph->protocol == IPPROTO_ICMP) | |
1556 | icmp_out_count(net, ((struct icmphdr *) | |
1557 | skb_transport_header(skb))->type); | |
1558 | ||
1559 | ip_cork_release(cork); | |
1560 | out: | |
1561 | return skb; | |
1562 | } | |
1563 | ||
1564 | int ip_send_skb(struct net *net, struct sk_buff *skb) | |
1565 | { | |
1566 | int err; | |
1567 | ||
1568 | err = ip_local_out(net, skb->sk, skb); | |
1569 | if (err) { | |
1570 | if (err > 0) | |
1571 | err = net_xmit_errno(err); | |
1572 | if (err) | |
1573 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); | |
1574 | } | |
1575 | ||
1576 | return err; | |
1577 | } | |
1578 | ||
1579 | int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4) | |
1580 | { | |
1581 | struct sk_buff *skb; | |
1582 | ||
1583 | skb = ip_finish_skb(sk, fl4); | |
1584 | if (!skb) | |
1585 | return 0; | |
1586 | ||
1587 | /* Netfilter gets whole the not fragmented skb. */ | |
1588 | return ip_send_skb(sock_net(sk), skb); | |
1589 | } | |
1590 | ||
1591 | /* | |
1592 | * Throw away all pending data on the socket. | |
1593 | */ | |
1594 | static void __ip_flush_pending_frames(struct sock *sk, | |
1595 | struct sk_buff_head *queue, | |
1596 | struct inet_cork *cork) | |
1597 | { | |
1598 | struct sk_buff *skb; | |
1599 | ||
1600 | while ((skb = __skb_dequeue_tail(queue)) != NULL) | |
1601 | kfree_skb(skb); | |
1602 | ||
1603 | ip_cork_release(cork); | |
1604 | } | |
1605 | ||
1606 | void ip_flush_pending_frames(struct sock *sk) | |
1607 | { | |
1608 | __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base); | |
1609 | } | |
1610 | ||
1611 | struct sk_buff *ip_make_skb(struct sock *sk, | |
1612 | struct flowi4 *fl4, | |
1613 | int getfrag(void *from, char *to, int offset, | |
1614 | int len, int odd, struct sk_buff *skb), | |
1615 | void *from, int length, int transhdrlen, | |
1616 | struct ipcm_cookie *ipc, struct rtable **rtp, | |
1617 | struct inet_cork *cork, unsigned int flags) | |
1618 | { | |
1619 | struct sk_buff_head queue; | |
1620 | int err; | |
1621 | ||
1622 | if (flags & MSG_PROBE) | |
1623 | return NULL; | |
1624 | ||
1625 | __skb_queue_head_init(&queue); | |
1626 | ||
1627 | cork->flags = 0; | |
1628 | cork->addr = 0; | |
1629 | cork->opt = NULL; | |
1630 | err = ip_setup_cork(sk, cork, ipc, rtp); | |
1631 | if (err) | |
1632 | return ERR_PTR(err); | |
1633 | ||
1634 | err = __ip_append_data(sk, fl4, &queue, cork, | |
1635 | ¤t->task_frag, getfrag, | |
1636 | from, length, transhdrlen, flags); | |
1637 | if (err) { | |
1638 | __ip_flush_pending_frames(sk, &queue, cork); | |
1639 | return ERR_PTR(err); | |
1640 | } | |
1641 | ||
1642 | return __ip_make_skb(sk, fl4, &queue, cork); | |
1643 | } | |
1644 | ||
1645 | /* | |
1646 | * Fetch data from kernel space and fill in checksum if needed. | |
1647 | */ | |
1648 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, | |
1649 | int len, int odd, struct sk_buff *skb) | |
1650 | { | |
1651 | __wsum csum; | |
1652 | ||
1653 | csum = csum_partial_copy_nocheck(dptr+offset, to, len); | |
1654 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
1655 | return 0; | |
1656 | } | |
1657 | ||
1658 | /* | |
1659 | * Generic function to send a packet as reply to another packet. | |
1660 | * Used to send some TCP resets/acks so far. | |
1661 | */ | |
1662 | void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, | |
1663 | const struct ip_options *sopt, | |
1664 | __be32 daddr, __be32 saddr, | |
1665 | const struct ip_reply_arg *arg, | |
1666 | unsigned int len, u64 transmit_time) | |
1667 | { | |
1668 | struct ip_options_data replyopts; | |
1669 | struct ipcm_cookie ipc; | |
1670 | struct flowi4 fl4; | |
1671 | struct rtable *rt = skb_rtable(skb); | |
1672 | struct net *net = sock_net(sk); | |
1673 | struct sk_buff *nskb; | |
1674 | int err; | |
1675 | int oif; | |
1676 | ||
1677 | if (__ip_options_echo(net, &replyopts.opt.opt, skb, sopt)) | |
1678 | return; | |
1679 | ||
1680 | ipcm_init(&ipc); | |
1681 | ipc.addr = daddr; | |
1682 | ipc.sockc.transmit_time = transmit_time; | |
1683 | ||
1684 | if (replyopts.opt.opt.optlen) { | |
1685 | ipc.opt = &replyopts.opt; | |
1686 | ||
1687 | if (replyopts.opt.opt.srr) | |
1688 | daddr = replyopts.opt.opt.faddr; | |
1689 | } | |
1690 | ||
1691 | oif = arg->bound_dev_if; | |
1692 | if (!oif && netif_index_is_l3_master(net, skb->skb_iif)) | |
1693 | oif = skb->skb_iif; | |
1694 | ||
1695 | flowi4_init_output(&fl4, oif, | |
1696 | IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark, | |
1697 | RT_TOS(arg->tos), | |
1698 | RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol, | |
1699 | ip_reply_arg_flowi_flags(arg), | |
1700 | daddr, saddr, | |
1701 | tcp_hdr(skb)->source, tcp_hdr(skb)->dest, | |
1702 | arg->uid); | |
1703 | security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); | |
1704 | rt = ip_route_output_key(net, &fl4); | |
1705 | if (IS_ERR(rt)) | |
1706 | return; | |
1707 | ||
1708 | inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK; | |
1709 | ||
1710 | sk->sk_protocol = ip_hdr(skb)->protocol; | |
1711 | sk->sk_bound_dev_if = arg->bound_dev_if; | |
1712 | sk->sk_sndbuf = sysctl_wmem_default; | |
1713 | ipc.sockc.mark = fl4.flowi4_mark; | |
1714 | err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, | |
1715 | len, 0, &ipc, &rt, MSG_DONTWAIT); | |
1716 | if (unlikely(err)) { | |
1717 | ip_flush_pending_frames(sk); | |
1718 | goto out; | |
1719 | } | |
1720 | ||
1721 | nskb = skb_peek(&sk->sk_write_queue); | |
1722 | if (nskb) { | |
1723 | if (arg->csumoffset >= 0) | |
1724 | *((__sum16 *)skb_transport_header(nskb) + | |
1725 | arg->csumoffset) = csum_fold(csum_add(nskb->csum, | |
1726 | arg->csum)); | |
1727 | nskb->ip_summed = CHECKSUM_NONE; | |
1728 | ip_push_pending_frames(sk, &fl4); | |
1729 | } | |
1730 | out: | |
1731 | ip_rt_put(rt); | |
1732 | } | |
1733 | ||
1734 | void __init ip_init(void) | |
1735 | { | |
1736 | ip_rt_init(); | |
1737 | inet_initpeers(); | |
1738 | ||
1739 | #if defined(CONFIG_IP_MULTICAST) | |
1740 | igmp_mc_init(); | |
1741 | #endif | |
1742 | } |