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 readability. |
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/gso.h> |
77 | #include <net/inetpeer.h> |
78 | #include <net/inet_ecn.h> |
79 | #include <net/lwtunnel.h> |
80 | #include <linux/bpf-cgroup.h> |
81 | #include <linux/igmp.h> |
82 | #include <linux/netfilter_ipv4.h> |
83 | #include <linux/netfilter_bridge.h> |
84 | #include <linux/netlink.h> |
85 | #include <linux/tcp.h> |
86 | |
87 | static int |
88 | ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
89 | unsigned int mtu, |
90 | int (*output)(struct net *, struct sock *, struct sk_buff *)); |
91 | |
92 | /* Generate a checksum for an outgoing IP datagram. */ |
93 | void ip_send_check(struct iphdr *iph) |
94 | { |
95 | iph->check = 0; |
96 | iph->check = ip_fast_csum(iph: (unsigned char *)iph, ihl: iph->ihl); |
97 | } |
98 | EXPORT_SYMBOL(ip_send_check); |
99 | |
100 | int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
101 | { |
102 | struct iphdr *iph = ip_hdr(skb); |
103 | |
104 | IP_INC_STATS(net, IPSTATS_MIB_OUTREQUESTS); |
105 | |
106 | iph_set_totlen(iph, len: skb->len); |
107 | ip_send_check(iph); |
108 | |
109 | /* if egress device is enslaved to an L3 master device pass the |
110 | * skb to its handler for processing |
111 | */ |
112 | skb = l3mdev_ip_out(sk, skb); |
113 | if (unlikely(!skb)) |
114 | return 0; |
115 | |
116 | skb->protocol = htons(ETH_P_IP); |
117 | |
118 | return nf_hook(pf: NFPROTO_IPV4, hook: NF_INET_LOCAL_OUT, |
119 | net, sk, skb, NULL, outdev: skb_dst(skb)->dev, |
120 | okfn: dst_output); |
121 | } |
122 | |
123 | int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
124 | { |
125 | int err; |
126 | |
127 | err = __ip_local_out(net, sk, skb); |
128 | if (likely(err == 1)) |
129 | err = dst_output(net, sk, skb); |
130 | |
131 | return err; |
132 | } |
133 | EXPORT_SYMBOL_GPL(ip_local_out); |
134 | |
135 | static inline int ip_select_ttl(const struct inet_sock *inet, |
136 | const struct dst_entry *dst) |
137 | { |
138 | int ttl = READ_ONCE(inet->uc_ttl); |
139 | |
140 | if (ttl < 0) |
141 | ttl = ip4_dst_hoplimit(dst); |
142 | return ttl; |
143 | } |
144 | |
145 | /* |
146 | * Add an ip header to a skbuff and send it out. |
147 | * |
148 | */ |
149 | int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk, |
150 | __be32 saddr, __be32 daddr, struct ip_options_rcu *opt, |
151 | u8 tos) |
152 | { |
153 | const struct inet_sock *inet = inet_sk(sk); |
154 | struct rtable *rt = skb_rtable(skb); |
155 | struct net *net = sock_net(sk); |
156 | struct iphdr *iph; |
157 | |
158 | /* Build the IP header. */ |
159 | skb_push(skb, len: sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); |
160 | skb_reset_network_header(skb); |
161 | iph = ip_hdr(skb); |
162 | iph->version = 4; |
163 | iph->ihl = 5; |
164 | iph->tos = tos; |
165 | iph->ttl = ip_select_ttl(inet, dst: &rt->dst); |
166 | iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr); |
167 | iph->saddr = saddr; |
168 | iph->protocol = sk->sk_protocol; |
169 | /* Do not bother generating IPID for small packets (eg SYNACK) */ |
170 | if (skb->len <= IPV4_MIN_MTU || ip_dont_fragment(sk, dst: &rt->dst)) { |
171 | iph->frag_off = htons(IP_DF); |
172 | iph->id = 0; |
173 | } else { |
174 | iph->frag_off = 0; |
175 | /* TCP packets here are SYNACK with fat IPv4/TCP options. |
176 | * Avoid using the hashed IP ident generator. |
177 | */ |
178 | if (sk->sk_protocol == IPPROTO_TCP) |
179 | iph->id = (__force __be16)get_random_u16(); |
180 | else |
181 | __ip_select_ident(net, iph, segs: 1); |
182 | } |
183 | |
184 | if (opt && opt->opt.optlen) { |
185 | iph->ihl += opt->opt.optlen>>2; |
186 | ip_options_build(skb, opt: &opt->opt, daddr, rt); |
187 | } |
188 | |
189 | skb->priority = READ_ONCE(sk->sk_priority); |
190 | if (!skb->mark) |
191 | skb->mark = READ_ONCE(sk->sk_mark); |
192 | |
193 | /* Send it out. */ |
194 | return ip_local_out(net, skb->sk, skb); |
195 | } |
196 | EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); |
197 | |
198 | static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) |
199 | { |
200 | struct dst_entry *dst = skb_dst(skb); |
201 | struct rtable *rt = (struct rtable *)dst; |
202 | struct net_device *dev = dst->dev; |
203 | unsigned int hh_len = LL_RESERVED_SPACE(dev); |
204 | struct neighbour *neigh; |
205 | bool is_v6gw = false; |
206 | |
207 | if (rt->rt_type == RTN_MULTICAST) { |
208 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len); |
209 | } else if (rt->rt_type == RTN_BROADCAST) |
210 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len); |
211 | |
212 | /* OUTOCTETS should be counted after fragment */ |
213 | IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); |
214 | |
215 | if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { |
216 | skb = skb_expand_head(skb, headroom: hh_len); |
217 | if (!skb) |
218 | return -ENOMEM; |
219 | } |
220 | |
221 | if (lwtunnel_xmit_redirect(lwtstate: dst->lwtstate)) { |
222 | int res = lwtunnel_xmit(skb); |
223 | |
224 | if (res != LWTUNNEL_XMIT_CONTINUE) |
225 | return res; |
226 | } |
227 | |
228 | rcu_read_lock(); |
229 | neigh = ip_neigh_for_gw(rt, skb, is_v6gw: &is_v6gw); |
230 | if (!IS_ERR(ptr: neigh)) { |
231 | int res; |
232 | |
233 | sock_confirm_neigh(skb, n: neigh); |
234 | /* if crossing protocols, can not use the cached header */ |
235 | res = neigh_output(n: neigh, skb, skip_cache: is_v6gw); |
236 | rcu_read_unlock(); |
237 | return res; |
238 | } |
239 | rcu_read_unlock(); |
240 | |
241 | net_dbg_ratelimited("%s: No header cache and no neighbour!\n" , |
242 | __func__); |
243 | kfree_skb_reason(skb, reason: SKB_DROP_REASON_NEIGH_CREATEFAIL); |
244 | return PTR_ERR(ptr: neigh); |
245 | } |
246 | |
247 | static int ip_finish_output_gso(struct net *net, struct sock *sk, |
248 | struct sk_buff *skb, unsigned int mtu) |
249 | { |
250 | struct sk_buff *segs, *nskb; |
251 | netdev_features_t features; |
252 | int ret = 0; |
253 | |
254 | /* common case: seglen is <= mtu |
255 | */ |
256 | if (skb_gso_validate_network_len(skb, mtu)) |
257 | return ip_finish_output2(net, sk, skb); |
258 | |
259 | /* Slowpath - GSO segment length exceeds the egress MTU. |
260 | * |
261 | * This can happen in several cases: |
262 | * - Forwarding of a TCP GRO skb, when DF flag is not set. |
263 | * - Forwarding of an skb that arrived on a virtualization interface |
264 | * (virtio-net/vhost/tap) with TSO/GSO size set by other network |
265 | * stack. |
266 | * - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an |
267 | * interface with a smaller MTU. |
268 | * - Arriving GRO skb (or GSO skb in a virtualized environment) that is |
269 | * bridged to a NETIF_F_TSO tunnel stacked over an interface with an |
270 | * insufficient MTU. |
271 | */ |
272 | features = netif_skb_features(skb); |
273 | BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET); |
274 | segs = skb_gso_segment(skb, features: features & ~NETIF_F_GSO_MASK); |
275 | if (IS_ERR_OR_NULL(ptr: segs)) { |
276 | kfree_skb(skb); |
277 | return -ENOMEM; |
278 | } |
279 | |
280 | consume_skb(skb); |
281 | |
282 | skb_list_walk_safe(segs, segs, nskb) { |
283 | int err; |
284 | |
285 | skb_mark_not_on_list(skb: segs); |
286 | err = ip_fragment(net, sk, skb: segs, mtu, output: ip_finish_output2); |
287 | |
288 | if (err && ret == 0) |
289 | ret = err; |
290 | } |
291 | |
292 | return ret; |
293 | } |
294 | |
295 | static int __ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
296 | { |
297 | unsigned int mtu; |
298 | |
299 | #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) |
300 | /* Policy lookup after SNAT yielded a new policy */ |
301 | if (skb_dst(skb)->xfrm) { |
302 | IPCB(skb)->flags |= IPSKB_REROUTED; |
303 | return dst_output(net, sk, skb); |
304 | } |
305 | #endif |
306 | mtu = ip_skb_dst_mtu(sk, skb); |
307 | if (skb_is_gso(skb)) |
308 | return ip_finish_output_gso(net, sk, skb, mtu); |
309 | |
310 | if (skb->len > mtu || IPCB(skb)->frag_max_size) |
311 | return ip_fragment(net, sk, skb, mtu, output: ip_finish_output2); |
312 | |
313 | return ip_finish_output2(net, sk, skb); |
314 | } |
315 | |
316 | static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
317 | { |
318 | int ret; |
319 | |
320 | ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); |
321 | switch (ret) { |
322 | case NET_XMIT_SUCCESS: |
323 | return __ip_finish_output(net, sk, skb); |
324 | case NET_XMIT_CN: |
325 | return __ip_finish_output(net, sk, skb) ? : ret; |
326 | default: |
327 | kfree_skb_reason(skb, reason: SKB_DROP_REASON_BPF_CGROUP_EGRESS); |
328 | return ret; |
329 | } |
330 | } |
331 | |
332 | static int ip_mc_finish_output(struct net *net, struct sock *sk, |
333 | struct sk_buff *skb) |
334 | { |
335 | struct rtable *new_rt; |
336 | bool do_cn = false; |
337 | int ret, err; |
338 | |
339 | ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); |
340 | switch (ret) { |
341 | case NET_XMIT_CN: |
342 | do_cn = true; |
343 | fallthrough; |
344 | case NET_XMIT_SUCCESS: |
345 | break; |
346 | default: |
347 | kfree_skb_reason(skb, reason: SKB_DROP_REASON_BPF_CGROUP_EGRESS); |
348 | return ret; |
349 | } |
350 | |
351 | /* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting |
352 | * this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten, |
353 | * see ipv4_pktinfo_prepare(). |
354 | */ |
355 | new_rt = rt_dst_clone(dev: net->loopback_dev, rt: skb_rtable(skb)); |
356 | if (new_rt) { |
357 | new_rt->rt_iif = 0; |
358 | skb_dst_drop(skb); |
359 | skb_dst_set(skb, dst: &new_rt->dst); |
360 | } |
361 | |
362 | err = dev_loopback_xmit(net, sk, newskb: skb); |
363 | return (do_cn && err) ? ret : err; |
364 | } |
365 | |
366 | int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
367 | { |
368 | struct rtable *rt = skb_rtable(skb); |
369 | struct net_device *dev = rt->dst.dev; |
370 | |
371 | /* |
372 | * If the indicated interface is up and running, send the packet. |
373 | */ |
374 | skb->dev = dev; |
375 | skb->protocol = htons(ETH_P_IP); |
376 | |
377 | /* |
378 | * Multicasts are looped back for other local users |
379 | */ |
380 | |
381 | if (rt->rt_flags&RTCF_MULTICAST) { |
382 | if (sk_mc_loop(sk) |
383 | #ifdef CONFIG_IP_MROUTE |
384 | /* Small optimization: do not loopback not local frames, |
385 | which returned after forwarding; they will be dropped |
386 | by ip_mr_input in any case. |
387 | Note, that local frames are looped back to be delivered |
388 | to local recipients. |
389 | |
390 | This check is duplicated in ip_mr_input at the moment. |
391 | */ |
392 | && |
393 | ((rt->rt_flags & RTCF_LOCAL) || |
394 | !(IPCB(skb)->flags & IPSKB_FORWARDED)) |
395 | #endif |
396 | ) { |
397 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
398 | if (newskb) |
399 | NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_POST_ROUTING, |
400 | net, sk, skb: newskb, NULL, out: newskb->dev, |
401 | okfn: ip_mc_finish_output); |
402 | } |
403 | |
404 | /* Multicasts with ttl 0 must not go beyond the host */ |
405 | |
406 | if (ip_hdr(skb)->ttl == 0) { |
407 | kfree_skb(skb); |
408 | return 0; |
409 | } |
410 | } |
411 | |
412 | if (rt->rt_flags&RTCF_BROADCAST) { |
413 | struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
414 | if (newskb) |
415 | NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_POST_ROUTING, |
416 | net, sk, skb: newskb, NULL, out: newskb->dev, |
417 | okfn: ip_mc_finish_output); |
418 | } |
419 | |
420 | return NF_HOOK_COND(pf: NFPROTO_IPV4, hook: NF_INET_POST_ROUTING, |
421 | net, sk, skb, NULL, out: skb->dev, |
422 | okfn: ip_finish_output, |
423 | cond: !(IPCB(skb)->flags & IPSKB_REROUTED)); |
424 | } |
425 | |
426 | int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
427 | { |
428 | struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev; |
429 | |
430 | skb->dev = dev; |
431 | skb->protocol = htons(ETH_P_IP); |
432 | |
433 | return NF_HOOK_COND(pf: NFPROTO_IPV4, hook: NF_INET_POST_ROUTING, |
434 | net, sk, skb, in: indev, out: dev, |
435 | okfn: ip_finish_output, |
436 | cond: !(IPCB(skb)->flags & IPSKB_REROUTED)); |
437 | } |
438 | EXPORT_SYMBOL(ip_output); |
439 | |
440 | /* |
441 | * copy saddr and daddr, possibly using 64bit load/stores |
442 | * Equivalent to : |
443 | * iph->saddr = fl4->saddr; |
444 | * iph->daddr = fl4->daddr; |
445 | */ |
446 | static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4) |
447 | { |
448 | BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) != |
449 | offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr)); |
450 | |
451 | iph->saddr = fl4->saddr; |
452 | iph->daddr = fl4->daddr; |
453 | } |
454 | |
455 | /* Note: skb->sk can be different from sk, in case of tunnels */ |
456 | int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, |
457 | __u8 tos) |
458 | { |
459 | struct inet_sock *inet = inet_sk(sk); |
460 | struct net *net = sock_net(sk); |
461 | struct ip_options_rcu *inet_opt; |
462 | struct flowi4 *fl4; |
463 | struct rtable *rt; |
464 | struct iphdr *iph; |
465 | int res; |
466 | |
467 | /* Skip all of this if the packet is already routed, |
468 | * f.e. by something like SCTP. |
469 | */ |
470 | rcu_read_lock(); |
471 | inet_opt = rcu_dereference(inet->inet_opt); |
472 | fl4 = &fl->u.ip4; |
473 | rt = skb_rtable(skb); |
474 | if (rt) |
475 | goto packet_routed; |
476 | |
477 | /* Make sure we can route this packet. */ |
478 | rt = (struct rtable *)__sk_dst_check(sk, cookie: 0); |
479 | if (!rt) { |
480 | __be32 daddr; |
481 | |
482 | /* Use correct destination address if we have options. */ |
483 | daddr = inet->inet_daddr; |
484 | if (inet_opt && inet_opt->opt.srr) |
485 | daddr = inet_opt->opt.faddr; |
486 | |
487 | /* If this fails, retransmit mechanism of transport layer will |
488 | * keep trying until route appears or the connection times |
489 | * itself out. |
490 | */ |
491 | rt = ip_route_output_ports(net, fl4, sk, |
492 | daddr, saddr: inet->inet_saddr, |
493 | dport: inet->inet_dport, |
494 | sport: inet->inet_sport, |
495 | proto: sk->sk_protocol, |
496 | RT_CONN_FLAGS_TOS(sk, tos), |
497 | oif: sk->sk_bound_dev_if); |
498 | if (IS_ERR(ptr: rt)) |
499 | goto no_route; |
500 | sk_setup_caps(sk, dst: &rt->dst); |
501 | } |
502 | skb_dst_set_noref(skb, dst: &rt->dst); |
503 | |
504 | packet_routed: |
505 | if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway) |
506 | goto no_route; |
507 | |
508 | /* OK, we know where to send it, allocate and build IP header. */ |
509 | skb_push(skb, len: sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0)); |
510 | skb_reset_network_header(skb); |
511 | iph = ip_hdr(skb); |
512 | *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (tos & 0xff)); |
513 | if (ip_dont_fragment(sk, dst: &rt->dst) && !skb->ignore_df) |
514 | iph->frag_off = htons(IP_DF); |
515 | else |
516 | iph->frag_off = 0; |
517 | iph->ttl = ip_select_ttl(inet, dst: &rt->dst); |
518 | iph->protocol = sk->sk_protocol; |
519 | ip_copy_addrs(iph, fl4); |
520 | |
521 | /* Transport layer set skb->h.foo itself. */ |
522 | |
523 | if (inet_opt && inet_opt->opt.optlen) { |
524 | iph->ihl += inet_opt->opt.optlen >> 2; |
525 | ip_options_build(skb, opt: &inet_opt->opt, daddr: inet->inet_daddr, rt); |
526 | } |
527 | |
528 | ip_select_ident_segs(net, skb, sk, |
529 | skb_shinfo(skb)->gso_segs ?: 1); |
530 | |
531 | /* TODO : should we use skb->sk here instead of sk ? */ |
532 | skb->priority = READ_ONCE(sk->sk_priority); |
533 | skb->mark = READ_ONCE(sk->sk_mark); |
534 | |
535 | res = ip_local_out(net, sk, skb); |
536 | rcu_read_unlock(); |
537 | return res; |
538 | |
539 | no_route: |
540 | rcu_read_unlock(); |
541 | IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
542 | kfree_skb_reason(skb, reason: SKB_DROP_REASON_IP_OUTNOROUTES); |
543 | return -EHOSTUNREACH; |
544 | } |
545 | EXPORT_SYMBOL(__ip_queue_xmit); |
546 | |
547 | int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl) |
548 | { |
549 | return __ip_queue_xmit(sk, skb, fl, READ_ONCE(inet_sk(sk)->tos)); |
550 | } |
551 | EXPORT_SYMBOL(ip_queue_xmit); |
552 | |
553 | static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) |
554 | { |
555 | to->pkt_type = from->pkt_type; |
556 | to->priority = from->priority; |
557 | to->protocol = from->protocol; |
558 | to->skb_iif = from->skb_iif; |
559 | skb_dst_drop(skb: to); |
560 | skb_dst_copy(nskb: to, oskb: from); |
561 | to->dev = from->dev; |
562 | to->mark = from->mark; |
563 | |
564 | skb_copy_hash(to, from); |
565 | |
566 | #ifdef CONFIG_NET_SCHED |
567 | to->tc_index = from->tc_index; |
568 | #endif |
569 | nf_copy(dst: to, src: from); |
570 | skb_ext_copy(dst: to, src: from); |
571 | #if IS_ENABLED(CONFIG_IP_VS) |
572 | to->ipvs_property = from->ipvs_property; |
573 | #endif |
574 | skb_copy_secmark(to, from); |
575 | } |
576 | |
577 | static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
578 | unsigned int mtu, |
579 | int (*output)(struct net *, struct sock *, struct sk_buff *)) |
580 | { |
581 | struct iphdr *iph = ip_hdr(skb); |
582 | |
583 | if ((iph->frag_off & htons(IP_DF)) == 0) |
584 | return ip_do_fragment(net, sk, skb, output); |
585 | |
586 | if (unlikely(!skb->ignore_df || |
587 | (IPCB(skb)->frag_max_size && |
588 | IPCB(skb)->frag_max_size > mtu))) { |
589 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
590 | icmp_send(skb_in: skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, |
591 | htonl(mtu)); |
592 | kfree_skb(skb); |
593 | return -EMSGSIZE; |
594 | } |
595 | |
596 | return ip_do_fragment(net, sk, skb, output); |
597 | } |
598 | |
599 | void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph, |
600 | unsigned int hlen, struct ip_fraglist_iter *iter) |
601 | { |
602 | unsigned int first_len = skb_pagelen(skb); |
603 | |
604 | iter->frag = skb_shinfo(skb)->frag_list; |
605 | skb_frag_list_init(skb); |
606 | |
607 | iter->offset = 0; |
608 | iter->iph = iph; |
609 | iter->hlen = hlen; |
610 | |
611 | skb->data_len = first_len - skb_headlen(skb); |
612 | skb->len = first_len; |
613 | iph->tot_len = htons(first_len); |
614 | iph->frag_off = htons(IP_MF); |
615 | ip_send_check(iph); |
616 | } |
617 | EXPORT_SYMBOL(ip_fraglist_init); |
618 | |
619 | void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter) |
620 | { |
621 | unsigned int hlen = iter->hlen; |
622 | struct iphdr *iph = iter->iph; |
623 | struct sk_buff *frag; |
624 | |
625 | frag = iter->frag; |
626 | frag->ip_summed = CHECKSUM_NONE; |
627 | skb_reset_transport_header(skb: frag); |
628 | __skb_push(skb: frag, len: hlen); |
629 | skb_reset_network_header(skb: frag); |
630 | memcpy(skb_network_header(frag), iph, hlen); |
631 | iter->iph = ip_hdr(skb: frag); |
632 | iph = iter->iph; |
633 | iph->tot_len = htons(frag->len); |
634 | ip_copy_metadata(to: frag, from: skb); |
635 | iter->offset += skb->len - hlen; |
636 | iph->frag_off = htons(iter->offset >> 3); |
637 | if (frag->next) |
638 | iph->frag_off |= htons(IP_MF); |
639 | /* Ready, complete checksum */ |
640 | ip_send_check(iph); |
641 | } |
642 | EXPORT_SYMBOL(ip_fraglist_prepare); |
643 | |
644 | void ip_frag_init(struct sk_buff *skb, unsigned int hlen, |
645 | unsigned int ll_rs, unsigned int mtu, bool DF, |
646 | struct ip_frag_state *state) |
647 | { |
648 | struct iphdr *iph = ip_hdr(skb); |
649 | |
650 | state->DF = DF; |
651 | state->hlen = hlen; |
652 | state->ll_rs = ll_rs; |
653 | state->mtu = mtu; |
654 | |
655 | state->left = skb->len - hlen; /* Space per frame */ |
656 | state->ptr = hlen; /* Where to start from */ |
657 | |
658 | state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; |
659 | state->not_last_frag = iph->frag_off & htons(IP_MF); |
660 | } |
661 | EXPORT_SYMBOL(ip_frag_init); |
662 | |
663 | static void ip_frag_ipcb(struct sk_buff *from, struct sk_buff *to, |
664 | bool first_frag) |
665 | { |
666 | /* Copy the flags to each fragment. */ |
667 | IPCB(to)->flags = IPCB(from)->flags; |
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 (first_frag) |
676 | ip_options_fragment(skb: from); |
677 | } |
678 | |
679 | struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state) |
680 | { |
681 | unsigned int len = state->left; |
682 | struct sk_buff *skb2; |
683 | struct iphdr *iph; |
684 | |
685 | /* IF: it doesn't fit, use 'mtu' - the data space left */ |
686 | if (len > state->mtu) |
687 | len = state->mtu; |
688 | /* IF: we are not sending up to and including the packet end |
689 | then align the next start on an eight byte boundary */ |
690 | if (len < state->left) { |
691 | len &= ~7; |
692 | } |
693 | |
694 | /* Allocate buffer */ |
695 | skb2 = alloc_skb(size: len + state->hlen + state->ll_rs, GFP_ATOMIC); |
696 | if (!skb2) |
697 | return ERR_PTR(error: -ENOMEM); |
698 | |
699 | /* |
700 | * Set up data on packet |
701 | */ |
702 | |
703 | ip_copy_metadata(to: skb2, from: skb); |
704 | skb_reserve(skb: skb2, len: state->ll_rs); |
705 | skb_put(skb: skb2, len: len + state->hlen); |
706 | skb_reset_network_header(skb: skb2); |
707 | skb2->transport_header = skb2->network_header + state->hlen; |
708 | |
709 | /* |
710 | * Charge the memory for the fragment to any owner |
711 | * it might possess |
712 | */ |
713 | |
714 | if (skb->sk) |
715 | skb_set_owner_w(skb: skb2, sk: skb->sk); |
716 | |
717 | /* |
718 | * Copy the packet header into the new buffer. |
719 | */ |
720 | |
721 | skb_copy_from_linear_data(skb, to: skb_network_header(skb: skb2), len: state->hlen); |
722 | |
723 | /* |
724 | * Copy a block of the IP datagram. |
725 | */ |
726 | if (skb_copy_bits(skb, offset: state->ptr, to: skb_transport_header(skb: skb2), len)) |
727 | BUG(); |
728 | state->left -= len; |
729 | |
730 | /* |
731 | * Fill in the new header fields. |
732 | */ |
733 | iph = ip_hdr(skb: skb2); |
734 | iph->frag_off = htons((state->offset >> 3)); |
735 | if (state->DF) |
736 | iph->frag_off |= htons(IP_DF); |
737 | |
738 | /* |
739 | * Added AC : If we are fragmenting a fragment that's not the |
740 | * last fragment then keep MF on each bit |
741 | */ |
742 | if (state->left > 0 || state->not_last_frag) |
743 | iph->frag_off |= htons(IP_MF); |
744 | state->ptr += len; |
745 | state->offset += len; |
746 | |
747 | iph->tot_len = htons(len + state->hlen); |
748 | |
749 | ip_send_check(iph); |
750 | |
751 | return skb2; |
752 | } |
753 | EXPORT_SYMBOL(ip_frag_next); |
754 | |
755 | /* |
756 | * This IP datagram is too large to be sent in one piece. Break it up into |
757 | * smaller pieces (each of size equal to IP header plus |
758 | * a block of the data of the original IP data part) that will yet fit in a |
759 | * single device frame, and queue such a frame for sending. |
760 | */ |
761 | |
762 | int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
763 | int (*output)(struct net *, struct sock *, struct sk_buff *)) |
764 | { |
765 | struct iphdr *iph; |
766 | struct sk_buff *skb2; |
767 | bool mono_delivery_time = skb->mono_delivery_time; |
768 | struct rtable *rt = skb_rtable(skb); |
769 | unsigned int mtu, hlen, ll_rs; |
770 | struct ip_fraglist_iter iter; |
771 | ktime_t tstamp = skb->tstamp; |
772 | struct ip_frag_state state; |
773 | int err = 0; |
774 | |
775 | /* for offloaded checksums cleanup checksum before fragmentation */ |
776 | if (skb->ip_summed == CHECKSUM_PARTIAL && |
777 | (err = skb_checksum_help(skb))) |
778 | goto fail; |
779 | |
780 | /* |
781 | * Point into the IP datagram header. |
782 | */ |
783 | |
784 | iph = ip_hdr(skb); |
785 | |
786 | mtu = ip_skb_dst_mtu(sk, skb); |
787 | if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu) |
788 | mtu = IPCB(skb)->frag_max_size; |
789 | |
790 | /* |
791 | * Setup starting values. |
792 | */ |
793 | |
794 | hlen = iph->ihl * 4; |
795 | mtu = mtu - hlen; /* Size of data space */ |
796 | IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; |
797 | ll_rs = LL_RESERVED_SPACE(rt->dst.dev); |
798 | |
799 | /* When frag_list is given, use it. First, check its validity: |
800 | * some transformers could create wrong frag_list or break existing |
801 | * one, it is not prohibited. In this case fall back to copying. |
802 | * |
803 | * LATER: this step can be merged to real generation of fragments, |
804 | * we can switch to copy when see the first bad fragment. |
805 | */ |
806 | if (skb_has_frag_list(skb)) { |
807 | struct sk_buff *frag, *frag2; |
808 | unsigned int first_len = skb_pagelen(skb); |
809 | |
810 | if (first_len - hlen > mtu || |
811 | ((first_len - hlen) & 7) || |
812 | ip_is_fragment(iph) || |
813 | skb_cloned(skb) || |
814 | skb_headroom(skb) < ll_rs) |
815 | goto slow_path; |
816 | |
817 | skb_walk_frags(skb, frag) { |
818 | /* Correct geometry. */ |
819 | if (frag->len > mtu || |
820 | ((frag->len & 7) && frag->next) || |
821 | skb_headroom(skb: frag) < hlen + ll_rs) |
822 | goto slow_path_clean; |
823 | |
824 | /* Partially cloned skb? */ |
825 | if (skb_shared(skb: frag)) |
826 | goto slow_path_clean; |
827 | |
828 | BUG_ON(frag->sk); |
829 | if (skb->sk) { |
830 | frag->sk = skb->sk; |
831 | frag->destructor = sock_wfree; |
832 | } |
833 | skb->truesize -= frag->truesize; |
834 | } |
835 | |
836 | /* Everything is OK. Generate! */ |
837 | ip_fraglist_init(skb, iph, hlen, &iter); |
838 | |
839 | for (;;) { |
840 | /* Prepare header of the next frame, |
841 | * before previous one went down. */ |
842 | if (iter.frag) { |
843 | bool first_frag = (iter.offset == 0); |
844 | |
845 | IPCB(iter.frag)->flags = IPCB(skb)->flags; |
846 | ip_fraglist_prepare(skb, &iter); |
847 | if (first_frag && IPCB(skb)->opt.optlen) { |
848 | /* ipcb->opt is not populated for frags |
849 | * coming from __ip_make_skb(), |
850 | * ip_options_fragment() needs optlen |
851 | */ |
852 | IPCB(iter.frag)->opt.optlen = |
853 | IPCB(skb)->opt.optlen; |
854 | ip_options_fragment(skb: iter.frag); |
855 | ip_send_check(iter.iph); |
856 | } |
857 | } |
858 | |
859 | skb_set_delivery_time(skb, kt: tstamp, mono: mono_delivery_time); |
860 | err = output(net, sk, skb); |
861 | |
862 | if (!err) |
863 | IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); |
864 | if (err || !iter.frag) |
865 | break; |
866 | |
867 | skb = ip_fraglist_next(iter: &iter); |
868 | } |
869 | |
870 | if (err == 0) { |
871 | IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); |
872 | return 0; |
873 | } |
874 | |
875 | kfree_skb_list(segs: iter.frag); |
876 | |
877 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
878 | return err; |
879 | |
880 | slow_path_clean: |
881 | skb_walk_frags(skb, frag2) { |
882 | if (frag2 == frag) |
883 | break; |
884 | frag2->sk = NULL; |
885 | frag2->destructor = NULL; |
886 | skb->truesize += frag2->truesize; |
887 | } |
888 | } |
889 | |
890 | slow_path: |
891 | /* |
892 | * Fragment the datagram. |
893 | */ |
894 | |
895 | ip_frag_init(skb, hlen, ll_rs, mtu, IPCB(skb)->flags & IPSKB_FRAG_PMTU, |
896 | &state); |
897 | |
898 | /* |
899 | * Keep copying data until we run out. |
900 | */ |
901 | |
902 | while (state.left > 0) { |
903 | bool first_frag = (state.offset == 0); |
904 | |
905 | skb2 = ip_frag_next(skb, &state); |
906 | if (IS_ERR(ptr: skb2)) { |
907 | err = PTR_ERR(ptr: skb2); |
908 | goto fail; |
909 | } |
910 | ip_frag_ipcb(from: skb, to: skb2, first_frag); |
911 | |
912 | /* |
913 | * Put this fragment into the sending queue. |
914 | */ |
915 | skb_set_delivery_time(skb: skb2, kt: tstamp, mono: mono_delivery_time); |
916 | err = output(net, sk, skb2); |
917 | if (err) |
918 | goto fail; |
919 | |
920 | IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); |
921 | } |
922 | consume_skb(skb); |
923 | IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); |
924 | return err; |
925 | |
926 | fail: |
927 | kfree_skb(skb); |
928 | IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
929 | return err; |
930 | } |
931 | EXPORT_SYMBOL(ip_do_fragment); |
932 | |
933 | int |
934 | ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) |
935 | { |
936 | struct msghdr *msg = from; |
937 | |
938 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
939 | if (!copy_from_iter_full(addr: to, bytes: len, i: &msg->msg_iter)) |
940 | return -EFAULT; |
941 | } else { |
942 | __wsum csum = 0; |
943 | if (!csum_and_copy_from_iter_full(addr: to, bytes: len, csum: &csum, i: &msg->msg_iter)) |
944 | return -EFAULT; |
945 | skb->csum = csum_block_add(csum: skb->csum, csum2: csum, offset: odd); |
946 | } |
947 | return 0; |
948 | } |
949 | EXPORT_SYMBOL(ip_generic_getfrag); |
950 | |
951 | static int __ip_append_data(struct sock *sk, |
952 | struct flowi4 *fl4, |
953 | struct sk_buff_head *queue, |
954 | struct inet_cork *cork, |
955 | struct page_frag *pfrag, |
956 | int getfrag(void *from, char *to, int offset, |
957 | int len, int odd, struct sk_buff *skb), |
958 | void *from, int length, int transhdrlen, |
959 | unsigned int flags) |
960 | { |
961 | struct inet_sock *inet = inet_sk(sk); |
962 | struct ubuf_info *uarg = NULL; |
963 | struct sk_buff *skb; |
964 | struct ip_options *opt = cork->opt; |
965 | int hh_len; |
966 | int exthdrlen; |
967 | int mtu; |
968 | int copy; |
969 | int err; |
970 | int offset = 0; |
971 | bool zc = false; |
972 | unsigned int maxfraglen, , maxnonfragsize; |
973 | int csummode = CHECKSUM_NONE; |
974 | struct rtable *rt = (struct rtable *)cork->dst; |
975 | unsigned int wmem_alloc_delta = 0; |
976 | bool paged, = false; |
977 | u32 tskey = 0; |
978 | |
979 | skb = skb_peek_tail(list_: queue); |
980 | |
981 | exthdrlen = !skb ? rt->dst.header_len : 0; |
982 | mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize; |
983 | paged = !!cork->gso_size; |
984 | |
985 | if (cork->tx_flags & SKBTX_ANY_TSTAMP && |
986 | READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) |
987 | tskey = atomic_inc_return(v: &sk->sk_tskey) - 1; |
988 | |
989 | hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
990 | |
991 | fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); |
992 | maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; |
993 | maxnonfragsize = ip_sk_ignore_df(sk) ? IP_MAX_MTU : mtu; |
994 | |
995 | if (cork->length + length > maxnonfragsize - fragheaderlen) { |
996 | ip_local_error(sk, EMSGSIZE, daddr: fl4->daddr, dport: inet->inet_dport, |
997 | info: mtu - (opt ? opt->optlen : 0)); |
998 | return -EMSGSIZE; |
999 | } |
1000 | |
1001 | /* |
1002 | * transhdrlen > 0 means that this is the first fragment and we wish |
1003 | * it won't be fragmented in the future. |
1004 | */ |
1005 | if (transhdrlen && |
1006 | length + fragheaderlen <= mtu && |
1007 | rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) && |
1008 | (!(flags & MSG_MORE) || cork->gso_size) && |
1009 | (!exthdrlen || (rt->dst.dev->features & NETIF_F_HW_ESP_TX_CSUM))) |
1010 | csummode = CHECKSUM_PARTIAL; |
1011 | |
1012 | if ((flags & MSG_ZEROCOPY) && length) { |
1013 | struct msghdr *msg = from; |
1014 | |
1015 | if (getfrag == ip_generic_getfrag && msg->msg_ubuf) { |
1016 | if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb)) |
1017 | return -EINVAL; |
1018 | |
1019 | /* Leave uarg NULL if can't zerocopy, callers should |
1020 | * be able to handle it. |
1021 | */ |
1022 | if ((rt->dst.dev->features & NETIF_F_SG) && |
1023 | csummode == CHECKSUM_PARTIAL) { |
1024 | paged = true; |
1025 | zc = true; |
1026 | uarg = msg->msg_ubuf; |
1027 | } |
1028 | } else if (sock_flag(sk, flag: SOCK_ZEROCOPY)) { |
1029 | uarg = msg_zerocopy_realloc(sk, size: length, uarg: skb_zcopy(skb)); |
1030 | if (!uarg) |
1031 | return -ENOBUFS; |
1032 | extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ |
1033 | if (rt->dst.dev->features & NETIF_F_SG && |
1034 | csummode == CHECKSUM_PARTIAL) { |
1035 | paged = true; |
1036 | zc = true; |
1037 | } else { |
1038 | uarg_to_msgzc(uarg)->zerocopy = 0; |
1039 | skb_zcopy_set(skb, uarg, have_ref: &extra_uref); |
1040 | } |
1041 | } |
1042 | } else if ((flags & MSG_SPLICE_PAGES) && length) { |
1043 | if (inet_test_bit(HDRINCL, sk)) |
1044 | return -EPERM; |
1045 | if (rt->dst.dev->features & NETIF_F_SG && |
1046 | getfrag == ip_generic_getfrag) |
1047 | /* We need an empty buffer to attach stuff to */ |
1048 | paged = true; |
1049 | else |
1050 | flags &= ~MSG_SPLICE_PAGES; |
1051 | } |
1052 | |
1053 | cork->length += length; |
1054 | |
1055 | /* So, what's going on in the loop below? |
1056 | * |
1057 | * We use calculated fragment length to generate chained skb, |
1058 | * each of segments is IP fragment ready for sending to network after |
1059 | * adding appropriate IP header. |
1060 | */ |
1061 | |
1062 | if (!skb) |
1063 | goto alloc_new_skb; |
1064 | |
1065 | while (length > 0) { |
1066 | /* Check if the remaining data fits into current packet. */ |
1067 | copy = mtu - skb->len; |
1068 | if (copy < length) |
1069 | copy = maxfraglen - skb->len; |
1070 | if (copy <= 0) { |
1071 | char *data; |
1072 | unsigned int datalen; |
1073 | unsigned int fraglen; |
1074 | unsigned int fraggap; |
1075 | unsigned int alloclen, ; |
1076 | unsigned int pagedlen; |
1077 | struct sk_buff *skb_prev; |
1078 | alloc_new_skb: |
1079 | skb_prev = skb; |
1080 | if (skb_prev) |
1081 | fraggap = skb_prev->len - maxfraglen; |
1082 | else |
1083 | fraggap = 0; |
1084 | |
1085 | /* |
1086 | * If remaining data exceeds the mtu, |
1087 | * we know we need more fragment(s). |
1088 | */ |
1089 | datalen = length + fraggap; |
1090 | if (datalen > mtu - fragheaderlen) |
1091 | datalen = maxfraglen - fragheaderlen; |
1092 | fraglen = datalen + fragheaderlen; |
1093 | pagedlen = 0; |
1094 | |
1095 | alloc_extra = hh_len + 15; |
1096 | alloc_extra += exthdrlen; |
1097 | |
1098 | /* The last fragment gets additional space at tail. |
1099 | * Note, with MSG_MORE we overallocate on fragments, |
1100 | * because we have no idea what fragment will be |
1101 | * the last. |
1102 | */ |
1103 | if (datalen == length + fraggap) |
1104 | alloc_extra += rt->dst.trailer_len; |
1105 | |
1106 | if ((flags & MSG_MORE) && |
1107 | !(rt->dst.dev->features&NETIF_F_SG)) |
1108 | alloclen = mtu; |
1109 | else if (!paged && |
1110 | (fraglen + alloc_extra < SKB_MAX_ALLOC || |
1111 | !(rt->dst.dev->features & NETIF_F_SG))) |
1112 | alloclen = fraglen; |
1113 | else { |
1114 | alloclen = fragheaderlen + transhdrlen; |
1115 | pagedlen = datalen - transhdrlen; |
1116 | } |
1117 | |
1118 | alloclen += alloc_extra; |
1119 | |
1120 | if (transhdrlen) { |
1121 | skb = sock_alloc_send_skb(sk, size: alloclen, |
1122 | noblock: (flags & MSG_DONTWAIT), errcode: &err); |
1123 | } else { |
1124 | skb = NULL; |
1125 | if (refcount_read(r: &sk->sk_wmem_alloc) + wmem_alloc_delta <= |
1126 | 2 * sk->sk_sndbuf) |
1127 | skb = alloc_skb(size: alloclen, |
1128 | priority: sk->sk_allocation); |
1129 | if (unlikely(!skb)) |
1130 | err = -ENOBUFS; |
1131 | } |
1132 | if (!skb) |
1133 | goto error; |
1134 | |
1135 | /* |
1136 | * Fill in the control structures |
1137 | */ |
1138 | skb->ip_summed = csummode; |
1139 | skb->csum = 0; |
1140 | skb_reserve(skb, len: hh_len); |
1141 | |
1142 | /* |
1143 | * Find where to start putting bytes. |
1144 | */ |
1145 | data = skb_put(skb, len: fraglen + exthdrlen - pagedlen); |
1146 | skb_set_network_header(skb, offset: exthdrlen); |
1147 | skb->transport_header = (skb->network_header + |
1148 | fragheaderlen); |
1149 | data += fragheaderlen + exthdrlen; |
1150 | |
1151 | if (fraggap) { |
1152 | skb->csum = skb_copy_and_csum_bits( |
1153 | skb: skb_prev, offset: maxfraglen, |
1154 | to: data + transhdrlen, len: fraggap); |
1155 | skb_prev->csum = csum_sub(csum: skb_prev->csum, |
1156 | addend: skb->csum); |
1157 | data += fraggap; |
1158 | pskb_trim_unique(skb: skb_prev, len: maxfraglen); |
1159 | } |
1160 | |
1161 | copy = datalen - transhdrlen - fraggap - pagedlen; |
1162 | /* [!] NOTE: copy will be negative if pagedlen>0 |
1163 | * because then the equation reduces to -fraggap. |
1164 | */ |
1165 | if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { |
1166 | err = -EFAULT; |
1167 | kfree_skb(skb); |
1168 | goto error; |
1169 | } else if (flags & MSG_SPLICE_PAGES) { |
1170 | copy = 0; |
1171 | } |
1172 | |
1173 | offset += copy; |
1174 | length -= copy + transhdrlen; |
1175 | transhdrlen = 0; |
1176 | exthdrlen = 0; |
1177 | csummode = CHECKSUM_NONE; |
1178 | |
1179 | /* only the initial fragment is time stamped */ |
1180 | skb_shinfo(skb)->tx_flags = cork->tx_flags; |
1181 | cork->tx_flags = 0; |
1182 | skb_shinfo(skb)->tskey = tskey; |
1183 | tskey = 0; |
1184 | skb_zcopy_set(skb, uarg, have_ref: &extra_uref); |
1185 | |
1186 | if ((flags & MSG_CONFIRM) && !skb_prev) |
1187 | skb_set_dst_pending_confirm(skb, val: 1); |
1188 | |
1189 | /* |
1190 | * Put the packet on the pending queue. |
1191 | */ |
1192 | if (!skb->destructor) { |
1193 | skb->destructor = sock_wfree; |
1194 | skb->sk = sk; |
1195 | wmem_alloc_delta += skb->truesize; |
1196 | } |
1197 | __skb_queue_tail(list: queue, newsk: skb); |
1198 | continue; |
1199 | } |
1200 | |
1201 | if (copy > length) |
1202 | copy = length; |
1203 | |
1204 | if (!(rt->dst.dev->features&NETIF_F_SG) && |
1205 | skb_tailroom(skb) >= copy) { |
1206 | unsigned int off; |
1207 | |
1208 | off = skb->len; |
1209 | if (getfrag(from, skb_put(skb, len: copy), |
1210 | offset, copy, off, skb) < 0) { |
1211 | __skb_trim(skb, len: off); |
1212 | err = -EFAULT; |
1213 | goto error; |
1214 | } |
1215 | } else if (flags & MSG_SPLICE_PAGES) { |
1216 | struct msghdr *msg = from; |
1217 | |
1218 | err = -EIO; |
1219 | if (WARN_ON_ONCE(copy > msg->msg_iter.count)) |
1220 | goto error; |
1221 | |
1222 | err = skb_splice_from_iter(skb, iter: &msg->msg_iter, maxsize: copy, |
1223 | gfp: sk->sk_allocation); |
1224 | if (err < 0) |
1225 | goto error; |
1226 | copy = err; |
1227 | wmem_alloc_delta += copy; |
1228 | } else if (!zc) { |
1229 | int i = skb_shinfo(skb)->nr_frags; |
1230 | |
1231 | err = -ENOMEM; |
1232 | if (!sk_page_frag_refill(sk, pfrag)) |
1233 | goto error; |
1234 | |
1235 | skb_zcopy_downgrade_managed(skb); |
1236 | if (!skb_can_coalesce(skb, i, page: pfrag->page, |
1237 | off: pfrag->offset)) { |
1238 | err = -EMSGSIZE; |
1239 | if (i == MAX_SKB_FRAGS) |
1240 | goto error; |
1241 | |
1242 | __skb_fill_page_desc(skb, i, page: pfrag->page, |
1243 | off: pfrag->offset, size: 0); |
1244 | skb_shinfo(skb)->nr_frags = ++i; |
1245 | get_page(page: pfrag->page); |
1246 | } |
1247 | copy = min_t(int, copy, pfrag->size - pfrag->offset); |
1248 | if (getfrag(from, |
1249 | page_address(pfrag->page) + pfrag->offset, |
1250 | offset, copy, skb->len, skb) < 0) |
1251 | goto error_efault; |
1252 | |
1253 | pfrag->offset += copy; |
1254 | skb_frag_size_add(frag: &skb_shinfo(skb)->frags[i - 1], delta: copy); |
1255 | skb_len_add(skb, delta: copy); |
1256 | wmem_alloc_delta += copy; |
1257 | } else { |
1258 | err = skb_zerocopy_iter_dgram(skb, msg: from, len: copy); |
1259 | if (err < 0) |
1260 | goto error; |
1261 | } |
1262 | offset += copy; |
1263 | length -= copy; |
1264 | } |
1265 | |
1266 | if (wmem_alloc_delta) |
1267 | refcount_add(i: wmem_alloc_delta, r: &sk->sk_wmem_alloc); |
1268 | return 0; |
1269 | |
1270 | error_efault: |
1271 | err = -EFAULT; |
1272 | error: |
1273 | net_zcopy_put_abort(uarg, have_uref: extra_uref); |
1274 | cork->length -= length; |
1275 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
1276 | refcount_add(i: wmem_alloc_delta, r: &sk->sk_wmem_alloc); |
1277 | return err; |
1278 | } |
1279 | |
1280 | static int ip_setup_cork(struct sock *sk, struct inet_cork *cork, |
1281 | struct ipcm_cookie *ipc, struct rtable **rtp) |
1282 | { |
1283 | struct ip_options_rcu *opt; |
1284 | struct rtable *rt; |
1285 | |
1286 | rt = *rtp; |
1287 | if (unlikely(!rt)) |
1288 | return -EFAULT; |
1289 | |
1290 | /* |
1291 | * setup for corking. |
1292 | */ |
1293 | opt = ipc->opt; |
1294 | if (opt) { |
1295 | if (!cork->opt) { |
1296 | cork->opt = kmalloc(size: sizeof(struct ip_options) + 40, |
1297 | flags: sk->sk_allocation); |
1298 | if (unlikely(!cork->opt)) |
1299 | return -ENOBUFS; |
1300 | } |
1301 | memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen); |
1302 | cork->flags |= IPCORK_OPT; |
1303 | cork->addr = ipc->addr; |
1304 | } |
1305 | |
1306 | cork->fragsize = ip_sk_use_pmtu(sk) ? |
1307 | dst_mtu(dst: &rt->dst) : READ_ONCE(rt->dst.dev->mtu); |
1308 | |
1309 | if (!inetdev_valid_mtu(mtu: cork->fragsize)) |
1310 | return -ENETUNREACH; |
1311 | |
1312 | cork->gso_size = ipc->gso_size; |
1313 | |
1314 | cork->dst = &rt->dst; |
1315 | /* We stole this route, caller should not release it. */ |
1316 | *rtp = NULL; |
1317 | |
1318 | cork->length = 0; |
1319 | cork->ttl = ipc->ttl; |
1320 | cork->tos = ipc->tos; |
1321 | cork->mark = ipc->sockc.mark; |
1322 | cork->priority = ipc->priority; |
1323 | cork->transmit_time = ipc->sockc.transmit_time; |
1324 | cork->tx_flags = 0; |
1325 | sock_tx_timestamp(sk, tsflags: ipc->sockc.tsflags, tx_flags: &cork->tx_flags); |
1326 | |
1327 | return 0; |
1328 | } |
1329 | |
1330 | /* |
1331 | * ip_append_data() can make one large IP datagram from many pieces of |
1332 | * data. Each piece will be held on the socket until |
1333 | * ip_push_pending_frames() is called. Each piece can be a page or |
1334 | * non-page data. |
1335 | * |
1336 | * Not only UDP, other transport protocols - e.g. raw sockets - can use |
1337 | * this interface potentially. |
1338 | * |
1339 | * LATER: length must be adjusted by pad at tail, when it is required. |
1340 | */ |
1341 | int ip_append_data(struct sock *sk, struct flowi4 *fl4, |
1342 | int getfrag(void *from, char *to, int offset, int len, |
1343 | int odd, struct sk_buff *skb), |
1344 | void *from, int length, int transhdrlen, |
1345 | struct ipcm_cookie *ipc, struct rtable **rtp, |
1346 | unsigned int flags) |
1347 | { |
1348 | struct inet_sock *inet = inet_sk(sk); |
1349 | int err; |
1350 | |
1351 | if (flags&MSG_PROBE) |
1352 | return 0; |
1353 | |
1354 | if (skb_queue_empty(list: &sk->sk_write_queue)) { |
1355 | err = ip_setup_cork(sk, cork: &inet->cork.base, ipc, rtp); |
1356 | if (err) |
1357 | return err; |
1358 | } else { |
1359 | transhdrlen = 0; |
1360 | } |
1361 | |
1362 | return __ip_append_data(sk, fl4, queue: &sk->sk_write_queue, cork: &inet->cork.base, |
1363 | pfrag: sk_page_frag(sk), getfrag, |
1364 | from, length, transhdrlen, flags); |
1365 | } |
1366 | |
1367 | static void ip_cork_release(struct inet_cork *cork) |
1368 | { |
1369 | cork->flags &= ~IPCORK_OPT; |
1370 | kfree(objp: cork->opt); |
1371 | cork->opt = NULL; |
1372 | dst_release(dst: cork->dst); |
1373 | cork->dst = NULL; |
1374 | } |
1375 | |
1376 | /* |
1377 | * Combined all pending IP fragments on the socket as one IP datagram |
1378 | * and push them out. |
1379 | */ |
1380 | struct sk_buff *__ip_make_skb(struct sock *sk, |
1381 | struct flowi4 *fl4, |
1382 | struct sk_buff_head *queue, |
1383 | struct inet_cork *cork) |
1384 | { |
1385 | struct sk_buff *skb, *tmp_skb; |
1386 | struct sk_buff **tail_skb; |
1387 | struct inet_sock *inet = inet_sk(sk); |
1388 | struct net *net = sock_net(sk); |
1389 | struct ip_options *opt = NULL; |
1390 | struct rtable *rt = (struct rtable *)cork->dst; |
1391 | struct iphdr *iph; |
1392 | u8 pmtudisc, ttl; |
1393 | __be16 df = 0; |
1394 | |
1395 | skb = __skb_dequeue(list: queue); |
1396 | if (!skb) |
1397 | goto out; |
1398 | tail_skb = &(skb_shinfo(skb)->frag_list); |
1399 | |
1400 | /* move skb->data to ip header from ext header */ |
1401 | if (skb->data < skb_network_header(skb)) |
1402 | __skb_pull(skb, len: skb_network_offset(skb)); |
1403 | while ((tmp_skb = __skb_dequeue(list: queue)) != NULL) { |
1404 | __skb_pull(skb: tmp_skb, len: skb_network_header_len(skb)); |
1405 | *tail_skb = tmp_skb; |
1406 | tail_skb = &(tmp_skb->next); |
1407 | skb->len += tmp_skb->len; |
1408 | skb->data_len += tmp_skb->len; |
1409 | skb->truesize += tmp_skb->truesize; |
1410 | tmp_skb->destructor = NULL; |
1411 | tmp_skb->sk = NULL; |
1412 | } |
1413 | |
1414 | /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow |
1415 | * to fragment the frame generated here. No matter, what transforms |
1416 | * how transforms change size of the packet, it will come out. |
1417 | */ |
1418 | skb->ignore_df = ip_sk_ignore_df(sk); |
1419 | |
1420 | /* DF bit is set when we want to see DF on outgoing frames. |
1421 | * If ignore_df is set too, we still allow to fragment this frame |
1422 | * locally. */ |
1423 | pmtudisc = READ_ONCE(inet->pmtudisc); |
1424 | if (pmtudisc == IP_PMTUDISC_DO || |
1425 | pmtudisc == IP_PMTUDISC_PROBE || |
1426 | (skb->len <= dst_mtu(dst: &rt->dst) && |
1427 | ip_dont_fragment(sk, dst: &rt->dst))) |
1428 | df = htons(IP_DF); |
1429 | |
1430 | if (cork->flags & IPCORK_OPT) |
1431 | opt = cork->opt; |
1432 | |
1433 | if (cork->ttl != 0) |
1434 | ttl = cork->ttl; |
1435 | else if (rt->rt_type == RTN_MULTICAST) |
1436 | ttl = READ_ONCE(inet->mc_ttl); |
1437 | else |
1438 | ttl = ip_select_ttl(inet, dst: &rt->dst); |
1439 | |
1440 | iph = ip_hdr(skb); |
1441 | iph->version = 4; |
1442 | iph->ihl = 5; |
1443 | iph->tos = (cork->tos != -1) ? cork->tos : READ_ONCE(inet->tos); |
1444 | iph->frag_off = df; |
1445 | iph->ttl = ttl; |
1446 | iph->protocol = sk->sk_protocol; |
1447 | ip_copy_addrs(iph, fl4); |
1448 | ip_select_ident(net, skb, sk); |
1449 | |
1450 | if (opt) { |
1451 | iph->ihl += opt->optlen >> 2; |
1452 | ip_options_build(skb, opt, daddr: cork->addr, rt); |
1453 | } |
1454 | |
1455 | skb->priority = (cork->tos != -1) ? cork->priority: READ_ONCE(sk->sk_priority); |
1456 | skb->mark = cork->mark; |
1457 | skb->tstamp = cork->transmit_time; |
1458 | /* |
1459 | * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec |
1460 | * on dst refcount |
1461 | */ |
1462 | cork->dst = NULL; |
1463 | skb_dst_set(skb, dst: &rt->dst); |
1464 | |
1465 | if (iph->protocol == IPPROTO_ICMP) { |
1466 | u8 icmp_type; |
1467 | |
1468 | /* For such sockets, transhdrlen is zero when do ip_append_data(), |
1469 | * so icmphdr does not in skb linear region and can not get icmp_type |
1470 | * by icmp_hdr(skb)->type. |
1471 | */ |
1472 | if (sk->sk_type == SOCK_RAW && |
1473 | !inet_test_bit(HDRINCL, sk)) |
1474 | icmp_type = fl4->fl4_icmp_type; |
1475 | else |
1476 | icmp_type = icmp_hdr(skb)->type; |
1477 | icmp_out_count(net, type: icmp_type); |
1478 | } |
1479 | |
1480 | ip_cork_release(cork); |
1481 | out: |
1482 | return skb; |
1483 | } |
1484 | |
1485 | int ip_send_skb(struct net *net, struct sk_buff *skb) |
1486 | { |
1487 | int err; |
1488 | |
1489 | err = ip_local_out(net, skb->sk, skb); |
1490 | if (err) { |
1491 | if (err > 0) |
1492 | err = net_xmit_errno(err); |
1493 | if (err) |
1494 | IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); |
1495 | } |
1496 | |
1497 | return err; |
1498 | } |
1499 | |
1500 | int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4) |
1501 | { |
1502 | struct sk_buff *skb; |
1503 | |
1504 | skb = ip_finish_skb(sk, fl4); |
1505 | if (!skb) |
1506 | return 0; |
1507 | |
1508 | /* Netfilter gets whole the not fragmented skb. */ |
1509 | return ip_send_skb(net: sock_net(sk), skb); |
1510 | } |
1511 | |
1512 | /* |
1513 | * Throw away all pending data on the socket. |
1514 | */ |
1515 | static void __ip_flush_pending_frames(struct sock *sk, |
1516 | struct sk_buff_head *queue, |
1517 | struct inet_cork *cork) |
1518 | { |
1519 | struct sk_buff *skb; |
1520 | |
1521 | while ((skb = __skb_dequeue_tail(list: queue)) != NULL) |
1522 | kfree_skb(skb); |
1523 | |
1524 | ip_cork_release(cork); |
1525 | } |
1526 | |
1527 | void ip_flush_pending_frames(struct sock *sk) |
1528 | { |
1529 | __ip_flush_pending_frames(sk, queue: &sk->sk_write_queue, cork: &inet_sk(sk)->cork.base); |
1530 | } |
1531 | |
1532 | struct sk_buff *ip_make_skb(struct sock *sk, |
1533 | struct flowi4 *fl4, |
1534 | int getfrag(void *from, char *to, int offset, |
1535 | int len, int odd, struct sk_buff *skb), |
1536 | void *from, int length, int transhdrlen, |
1537 | struct ipcm_cookie *ipc, struct rtable **rtp, |
1538 | struct inet_cork *cork, unsigned int flags) |
1539 | { |
1540 | struct sk_buff_head queue; |
1541 | int err; |
1542 | |
1543 | if (flags & MSG_PROBE) |
1544 | return NULL; |
1545 | |
1546 | __skb_queue_head_init(list: &queue); |
1547 | |
1548 | cork->flags = 0; |
1549 | cork->addr = 0; |
1550 | cork->opt = NULL; |
1551 | err = ip_setup_cork(sk, cork, ipc, rtp); |
1552 | if (err) |
1553 | return ERR_PTR(error: err); |
1554 | |
1555 | err = __ip_append_data(sk, fl4, queue: &queue, cork, |
1556 | pfrag: ¤t->task_frag, getfrag, |
1557 | from, length, transhdrlen, flags); |
1558 | if (err) { |
1559 | __ip_flush_pending_frames(sk, queue: &queue, cork); |
1560 | return ERR_PTR(error: err); |
1561 | } |
1562 | |
1563 | return __ip_make_skb(sk, fl4, queue: &queue, cork); |
1564 | } |
1565 | |
1566 | /* |
1567 | * Fetch data from kernel space and fill in checksum if needed. |
1568 | */ |
1569 | static int ip_reply_glue_bits(void *dptr, char *to, int offset, |
1570 | int len, int odd, struct sk_buff *skb) |
1571 | { |
1572 | __wsum csum; |
1573 | |
1574 | csum = csum_partial_copy_nocheck(src: dptr+offset, dst: to, len); |
1575 | skb->csum = csum_block_add(csum: skb->csum, csum2: csum, offset: odd); |
1576 | return 0; |
1577 | } |
1578 | |
1579 | /* |
1580 | * Generic function to send a packet as reply to another packet. |
1581 | * Used to send some TCP resets/acks so far. |
1582 | */ |
1583 | void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, |
1584 | const struct ip_options *sopt, |
1585 | __be32 daddr, __be32 saddr, |
1586 | const struct ip_reply_arg *arg, |
1587 | unsigned int len, u64 transmit_time, u32 txhash) |
1588 | { |
1589 | struct ip_options_data replyopts; |
1590 | struct ipcm_cookie ipc; |
1591 | struct flowi4 fl4; |
1592 | struct rtable *rt = skb_rtable(skb); |
1593 | struct net *net = sock_net(sk); |
1594 | struct sk_buff *nskb; |
1595 | int err; |
1596 | int oif; |
1597 | |
1598 | if (__ip_options_echo(net, dopt: &replyopts.opt.opt, skb, sopt)) |
1599 | return; |
1600 | |
1601 | ipcm_init(ipcm: &ipc); |
1602 | ipc.addr = daddr; |
1603 | ipc.sockc.transmit_time = transmit_time; |
1604 | |
1605 | if (replyopts.opt.opt.optlen) { |
1606 | ipc.opt = &replyopts.opt; |
1607 | |
1608 | if (replyopts.opt.opt.srr) |
1609 | daddr = replyopts.opt.opt.faddr; |
1610 | } |
1611 | |
1612 | oif = arg->bound_dev_if; |
1613 | if (!oif && netif_index_is_l3_master(net, ifindex: skb->skb_iif)) |
1614 | oif = skb->skb_iif; |
1615 | |
1616 | flowi4_init_output(fl4: &fl4, oif, |
1617 | IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark, |
1618 | RT_TOS(arg->tos), |
1619 | scope: RT_SCOPE_UNIVERSE, proto: ip_hdr(skb)->protocol, |
1620 | flags: ip_reply_arg_flowi_flags(arg), |
1621 | daddr, saddr, |
1622 | dport: tcp_hdr(skb)->source, sport: tcp_hdr(skb)->dest, |
1623 | uid: arg->uid); |
1624 | security_skb_classify_flow(skb, flic: flowi4_to_flowi_common(fl4: &fl4)); |
1625 | rt = ip_route_output_flow(net, flp: &fl4, sk); |
1626 | if (IS_ERR(ptr: rt)) |
1627 | return; |
1628 | |
1629 | inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK; |
1630 | |
1631 | sk->sk_protocol = ip_hdr(skb)->protocol; |
1632 | sk->sk_bound_dev_if = arg->bound_dev_if; |
1633 | sk->sk_sndbuf = READ_ONCE(sysctl_wmem_default); |
1634 | ipc.sockc.mark = fl4.flowi4_mark; |
1635 | err = ip_append_data(sk, fl4: &fl4, getfrag: ip_reply_glue_bits, from: arg->iov->iov_base, |
1636 | length: len, transhdrlen: 0, ipc: &ipc, rtp: &rt, MSG_DONTWAIT); |
1637 | if (unlikely(err)) { |
1638 | ip_flush_pending_frames(sk); |
1639 | goto out; |
1640 | } |
1641 | |
1642 | nskb = skb_peek(list_: &sk->sk_write_queue); |
1643 | if (nskb) { |
1644 | if (arg->csumoffset >= 0) |
1645 | *((__sum16 *)skb_transport_header(skb: nskb) + |
1646 | arg->csumoffset) = csum_fold(sum: csum_add(csum: nskb->csum, |
1647 | addend: arg->csum)); |
1648 | nskb->ip_summed = CHECKSUM_NONE; |
1649 | nskb->mono_delivery_time = !!transmit_time; |
1650 | if (txhash) |
1651 | skb_set_hash(skb: nskb, hash: txhash, type: PKT_HASH_TYPE_L4); |
1652 | ip_push_pending_frames(sk, fl4: &fl4); |
1653 | } |
1654 | out: |
1655 | ip_rt_put(rt); |
1656 | } |
1657 | |
1658 | void __init ip_init(void) |
1659 | { |
1660 | ip_rt_init(); |
1661 | inet_initpeers(); |
1662 | |
1663 | #if defined(CONFIG_IP_MULTICAST) |
1664 | igmp_mc_init(); |
1665 | #endif |
1666 | } |
1667 | |