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2303f994 PK |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Multipath TCP | |
3 | * | |
4 | * Copyright (c) 2017 - 2019, Intel Corporation. | |
5 | */ | |
6 | ||
79c0949e PK |
7 | #define pr_fmt(fmt) "MPTCP: " fmt |
8 | ||
2303f994 PK |
9 | #include <linux/kernel.h> |
10 | #include <linux/module.h> | |
11 | #include <linux/netdevice.h> | |
f296234c | 12 | #include <crypto/algapi.h> |
bd697222 | 13 | #include <crypto/sha.h> |
2303f994 PK |
14 | #include <net/sock.h> |
15 | #include <net/inet_common.h> | |
16 | #include <net/inet_hashtables.h> | |
17 | #include <net/protocol.h> | |
18 | #include <net/tcp.h> | |
cec37a6e PK |
19 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
20 | #include <net/ip6_route.h> | |
21 | #endif | |
2303f994 PK |
22 | #include <net/mptcp.h> |
23 | #include "protocol.h" | |
fc518953 FW |
24 | #include "mib.h" |
25 | ||
26 | static void SUBFLOW_REQ_INC_STATS(struct request_sock *req, | |
27 | enum linux_mptcp_mib_field field) | |
28 | { | |
29 | MPTCP_INC_STATS(sock_net(req_to_sk(req)), field); | |
30 | } | |
2303f994 | 31 | |
79c0949e PK |
32 | static void subflow_req_destructor(struct request_sock *req) |
33 | { | |
34 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
35 | ||
36 | pr_debug("subflow_req=%p", subflow_req); | |
37 | ||
8fd4de12 PA |
38 | if (subflow_req->msk) |
39 | sock_put((struct sock *)subflow_req->msk); | |
40 | ||
2c5ebd00 | 41 | mptcp_token_destroy_request(req); |
79c0949e PK |
42 | tcp_request_sock_ops.destructor(req); |
43 | } | |
44 | ||
f296234c PK |
45 | static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2, |
46 | void *hmac) | |
47 | { | |
48 | u8 msg[8]; | |
49 | ||
50 | put_unaligned_be32(nonce1, &msg[0]); | |
51 | put_unaligned_be32(nonce2, &msg[4]); | |
52 | ||
53 | mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac); | |
54 | } | |
55 | ||
4cf8b7e4 PA |
56 | static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk) |
57 | { | |
58 | return mptcp_is_fully_established((void *)msk) && | |
59 | READ_ONCE(msk->pm.accept_subflow); | |
60 | } | |
61 | ||
f296234c | 62 | /* validate received token and create truncated hmac and nonce for SYN-ACK */ |
8fd4de12 PA |
63 | static struct mptcp_sock *subflow_token_join_request(struct request_sock *req, |
64 | const struct sk_buff *skb) | |
f296234c PK |
65 | { |
66 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
bd697222 | 67 | u8 hmac[SHA256_DIGEST_SIZE]; |
f296234c PK |
68 | struct mptcp_sock *msk; |
69 | int local_id; | |
70 | ||
71 | msk = mptcp_token_get_sock(subflow_req->token); | |
72 | if (!msk) { | |
fc518953 | 73 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN); |
8fd4de12 | 74 | return NULL; |
f296234c PK |
75 | } |
76 | ||
77 | local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req); | |
78 | if (local_id < 0) { | |
79 | sock_put((struct sock *)msk); | |
8fd4de12 | 80 | return NULL; |
f296234c PK |
81 | } |
82 | subflow_req->local_id = local_id; | |
83 | ||
84 | get_random_bytes(&subflow_req->local_nonce, sizeof(u32)); | |
85 | ||
86 | subflow_generate_hmac(msk->local_key, msk->remote_key, | |
87 | subflow_req->local_nonce, | |
88 | subflow_req->remote_nonce, hmac); | |
89 | ||
90 | subflow_req->thmac = get_unaligned_be64(hmac); | |
8fd4de12 | 91 | return msk; |
f296234c PK |
92 | } |
93 | ||
78d8b7bc | 94 | static int __subflow_init_req(struct request_sock *req, const struct sock *sk_listener) |
cec37a6e | 95 | { |
cec37a6e | 96 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
cec37a6e PK |
97 | |
98 | subflow_req->mp_capable = 0; | |
f296234c | 99 | subflow_req->mp_join = 0; |
8fd4de12 | 100 | subflow_req->msk = NULL; |
2c5ebd00 | 101 | mptcp_token_init_request(req); |
cec37a6e PK |
102 | |
103 | #ifdef CONFIG_TCP_MD5SIG | |
104 | /* no MPTCP if MD5SIG is enabled on this socket or we may run out of | |
105 | * TCP option space. | |
106 | */ | |
107 | if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) | |
78d8b7bc | 108 | return -EINVAL; |
cec37a6e PK |
109 | #endif |
110 | ||
78d8b7bc FW |
111 | return 0; |
112 | } | |
113 | ||
114 | static void subflow_init_req(struct request_sock *req, | |
115 | const struct sock *sk_listener, | |
116 | struct sk_buff *skb) | |
117 | { | |
118 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); | |
119 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
120 | struct mptcp_options_received mp_opt; | |
121 | int ret; | |
122 | ||
123 | pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); | |
124 | ||
125 | ret = __subflow_init_req(req, sk_listener); | |
126 | if (ret) | |
127 | return; | |
128 | ||
129 | mptcp_get_options(skb, &mp_opt); | |
130 | ||
cfde141e | 131 | if (mp_opt.mp_capable) { |
fc518953 FW |
132 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); |
133 | ||
cfde141e | 134 | if (mp_opt.mp_join) |
fc518953 | 135 | return; |
cfde141e | 136 | } else if (mp_opt.mp_join) { |
fc518953 FW |
137 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX); |
138 | } | |
f296234c | 139 | |
cfde141e | 140 | if (mp_opt.mp_capable && listener->request_mptcp) { |
535fb815 FW |
141 | int err, retries = 4; |
142 | ||
c83a47e5 | 143 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
535fb815 FW |
144 | again: |
145 | do { | |
146 | get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key)); | |
147 | } while (subflow_req->local_key == 0); | |
79c0949e | 148 | |
c83a47e5 FW |
149 | if (unlikely(req->syncookie)) { |
150 | mptcp_crypto_key_sha(subflow_req->local_key, | |
151 | &subflow_req->token, | |
152 | &subflow_req->idsn); | |
153 | if (mptcp_token_exists(subflow_req->token)) { | |
154 | if (retries-- > 0) | |
155 | goto again; | |
156 | } else { | |
157 | subflow_req->mp_capable = 1; | |
158 | } | |
159 | return; | |
160 | } | |
161 | ||
79c0949e PK |
162 | err = mptcp_token_new_request(req); |
163 | if (err == 0) | |
164 | subflow_req->mp_capable = 1; | |
535fb815 FW |
165 | else if (retries-- > 0) |
166 | goto again; | |
79c0949e | 167 | |
cfde141e | 168 | } else if (mp_opt.mp_join && listener->request_mptcp) { |
ec3edaa7 | 169 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
f296234c | 170 | subflow_req->mp_join = 1; |
cfde141e PA |
171 | subflow_req->backup = mp_opt.backup; |
172 | subflow_req->remote_id = mp_opt.join_id; | |
173 | subflow_req->token = mp_opt.token; | |
174 | subflow_req->remote_nonce = mp_opt.nonce; | |
8fd4de12 | 175 | subflow_req->msk = subflow_token_join_request(req, skb); |
9466a1cc FW |
176 | |
177 | if (unlikely(req->syncookie) && subflow_req->msk) { | |
178 | if (mptcp_can_accept_new_subflow(subflow_req->msk)) | |
179 | subflow_init_req_cookie_join_save(subflow_req, skb); | |
180 | } | |
181 | ||
8fd4de12 PA |
182 | pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, |
183 | subflow_req->remote_nonce, subflow_req->msk); | |
cec37a6e PK |
184 | } |
185 | } | |
186 | ||
c83a47e5 FW |
187 | int mptcp_subflow_init_cookie_req(struct request_sock *req, |
188 | const struct sock *sk_listener, | |
189 | struct sk_buff *skb) | |
190 | { | |
191 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); | |
192 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
193 | struct mptcp_options_received mp_opt; | |
194 | int err; | |
195 | ||
196 | err = __subflow_init_req(req, sk_listener); | |
197 | if (err) | |
198 | return err; | |
199 | ||
200 | mptcp_get_options(skb, &mp_opt); | |
201 | ||
202 | if (mp_opt.mp_capable && mp_opt.mp_join) | |
203 | return -EINVAL; | |
204 | ||
205 | if (mp_opt.mp_capable && listener->request_mptcp) { | |
206 | if (mp_opt.sndr_key == 0) | |
207 | return -EINVAL; | |
208 | ||
209 | subflow_req->local_key = mp_opt.rcvr_key; | |
210 | err = mptcp_token_new_request(req); | |
211 | if (err) | |
212 | return err; | |
213 | ||
214 | subflow_req->mp_capable = 1; | |
215 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; | |
9466a1cc FW |
216 | } else if (mp_opt.mp_join && listener->request_mptcp) { |
217 | if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) | |
218 | return -EINVAL; | |
219 | ||
220 | if (mptcp_can_accept_new_subflow(subflow_req->msk)) | |
221 | subflow_req->mp_join = 1; | |
222 | ||
223 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; | |
c83a47e5 FW |
224 | } |
225 | ||
226 | return 0; | |
227 | } | |
228 | EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req); | |
229 | ||
cec37a6e PK |
230 | static void subflow_v4_init_req(struct request_sock *req, |
231 | const struct sock *sk_listener, | |
232 | struct sk_buff *skb) | |
233 | { | |
234 | tcp_rsk(req)->is_mptcp = 1; | |
235 | ||
236 | tcp_request_sock_ipv4_ops.init_req(req, sk_listener, skb); | |
237 | ||
238 | subflow_init_req(req, sk_listener, skb); | |
239 | } | |
240 | ||
241 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
242 | static void subflow_v6_init_req(struct request_sock *req, | |
243 | const struct sock *sk_listener, | |
244 | struct sk_buff *skb) | |
245 | { | |
246 | tcp_rsk(req)->is_mptcp = 1; | |
247 | ||
248 | tcp_request_sock_ipv6_ops.init_req(req, sk_listener, skb); | |
249 | ||
250 | subflow_init_req(req, sk_listener, skb); | |
251 | } | |
252 | #endif | |
253 | ||
ec3edaa7 PK |
254 | /* validate received truncated hmac and create hmac for third ACK */ |
255 | static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow) | |
256 | { | |
bd697222 | 257 | u8 hmac[SHA256_DIGEST_SIZE]; |
ec3edaa7 PK |
258 | u64 thmac; |
259 | ||
260 | subflow_generate_hmac(subflow->remote_key, subflow->local_key, | |
261 | subflow->remote_nonce, subflow->local_nonce, | |
262 | hmac); | |
263 | ||
264 | thmac = get_unaligned_be64(hmac); | |
265 | pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n", | |
266 | subflow, subflow->token, | |
267 | (unsigned long long)thmac, | |
268 | (unsigned long long)subflow->thmac); | |
269 | ||
270 | return thmac == subflow->thmac; | |
271 | } | |
272 | ||
cec37a6e PK |
273 | static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) |
274 | { | |
275 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
cfde141e | 276 | struct mptcp_options_received mp_opt; |
c3c123d1 | 277 | struct sock *parent = subflow->conn; |
cec37a6e PK |
278 | |
279 | subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); | |
280 | ||
1200832c | 281 | if (inet_sk_state_load(parent) == TCP_SYN_SENT) { |
c3c123d1 DC |
282 | inet_sk_state_store(parent, TCP_ESTABLISHED); |
283 | parent->sk_state_change(parent); | |
284 | } | |
285 | ||
263e1201 PA |
286 | /* be sure no special action on any packet other than syn-ack */ |
287 | if (subflow->conn_finished) | |
288 | return; | |
289 | ||
b0977bb2 | 290 | subflow->rel_write_seq = 1; |
263e1201 | 291 | subflow->conn_finished = 1; |
e1ff9e82 DC |
292 | subflow->ssn_offset = TCP_SKB_CB(skb)->seq; |
293 | pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset); | |
263e1201 | 294 | |
cfde141e | 295 | mptcp_get_options(skb, &mp_opt); |
fa25e815 PA |
296 | if (subflow->request_mptcp) { |
297 | if (!mp_opt.mp_capable) { | |
298 | MPTCP_INC_STATS(sock_net(sk), | |
299 | MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); | |
300 | mptcp_do_fallback(sk); | |
301 | pr_fallback(mptcp_sk(subflow->conn)); | |
302 | goto fallback; | |
303 | } | |
304 | ||
263e1201 PA |
305 | subflow->mp_capable = 1; |
306 | subflow->can_ack = 1; | |
cfde141e | 307 | subflow->remote_key = mp_opt.sndr_key; |
263e1201 PA |
308 | pr_debug("subflow=%p, remote_key=%llu", subflow, |
309 | subflow->remote_key); | |
fa25e815 PA |
310 | mptcp_finish_connect(sk); |
311 | } else if (subflow->request_join) { | |
312 | u8 hmac[SHA256_DIGEST_SIZE]; | |
313 | ||
314 | if (!mp_opt.mp_join) | |
315 | goto do_reset; | |
316 | ||
cfde141e PA |
317 | subflow->thmac = mp_opt.thmac; |
318 | subflow->remote_nonce = mp_opt.nonce; | |
263e1201 PA |
319 | pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow, |
320 | subflow->thmac, subflow->remote_nonce); | |
263e1201 | 321 | |
ec3edaa7 | 322 | if (!subflow_thmac_valid(subflow)) { |
fc518953 | 323 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC); |
ec3edaa7 PK |
324 | goto do_reset; |
325 | } | |
326 | ||
327 | subflow_generate_hmac(subflow->local_key, subflow->remote_key, | |
328 | subflow->local_nonce, | |
329 | subflow->remote_nonce, | |
bd697222 | 330 | hmac); |
bd697222 | 331 | memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN); |
ec3edaa7 | 332 | |
ec3edaa7 PK |
333 | if (!mptcp_finish_join(sk)) |
334 | goto do_reset; | |
335 | ||
fa25e815 | 336 | subflow->mp_join = 1; |
fc518953 | 337 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX); |
fa25e815 PA |
338 | } else if (mptcp_check_fallback(sk)) { |
339 | fallback: | |
340 | mptcp_rcv_space_init(mptcp_sk(parent), sk); | |
cec37a6e | 341 | } |
fa25e815 PA |
342 | return; |
343 | ||
344 | do_reset: | |
345 | tcp_send_active_reset(sk, GFP_ATOMIC); | |
346 | tcp_done(sk); | |
cec37a6e PK |
347 | } |
348 | ||
08b8d080 FW |
349 | struct request_sock_ops mptcp_subflow_request_sock_ops; |
350 | EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops); | |
cec37a6e PK |
351 | static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops; |
352 | ||
353 | static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) | |
354 | { | |
355 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
356 | ||
357 | pr_debug("subflow=%p", subflow); | |
358 | ||
359 | /* Never answer to SYNs sent to broadcast or multicast */ | |
360 | if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) | |
361 | goto drop; | |
362 | ||
08b8d080 | 363 | return tcp_conn_request(&mptcp_subflow_request_sock_ops, |
cec37a6e PK |
364 | &subflow_request_sock_ipv4_ops, |
365 | sk, skb); | |
366 | drop: | |
367 | tcp_listendrop(sk); | |
368 | return 0; | |
369 | } | |
370 | ||
371 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
372 | static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops; | |
373 | static struct inet_connection_sock_af_ops subflow_v6_specific; | |
374 | static struct inet_connection_sock_af_ops subflow_v6m_specific; | |
375 | ||
376 | static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) | |
377 | { | |
378 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
379 | ||
380 | pr_debug("subflow=%p", subflow); | |
381 | ||
382 | if (skb->protocol == htons(ETH_P_IP)) | |
383 | return subflow_v4_conn_request(sk, skb); | |
384 | ||
385 | if (!ipv6_unicast_destination(skb)) | |
386 | goto drop; | |
387 | ||
08b8d080 | 388 | return tcp_conn_request(&mptcp_subflow_request_sock_ops, |
cec37a6e PK |
389 | &subflow_request_sock_ipv6_ops, sk, skb); |
390 | ||
391 | drop: | |
392 | tcp_listendrop(sk); | |
393 | return 0; /* don't send reset */ | |
394 | } | |
395 | #endif | |
396 | ||
f296234c PK |
397 | /* validate hmac received in third ACK */ |
398 | static bool subflow_hmac_valid(const struct request_sock *req, | |
cfde141e | 399 | const struct mptcp_options_received *mp_opt) |
f296234c PK |
400 | { |
401 | const struct mptcp_subflow_request_sock *subflow_req; | |
bd697222 | 402 | u8 hmac[SHA256_DIGEST_SIZE]; |
f296234c | 403 | struct mptcp_sock *msk; |
f296234c PK |
404 | |
405 | subflow_req = mptcp_subflow_rsk(req); | |
8fd4de12 | 406 | msk = subflow_req->msk; |
f296234c PK |
407 | if (!msk) |
408 | return false; | |
409 | ||
410 | subflow_generate_hmac(msk->remote_key, msk->local_key, | |
411 | subflow_req->remote_nonce, | |
412 | subflow_req->local_nonce, hmac); | |
413 | ||
8fd4de12 | 414 | return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN); |
f296234c PK |
415 | } |
416 | ||
df1036da FW |
417 | static void mptcp_sock_destruct(struct sock *sk) |
418 | { | |
419 | /* if new mptcp socket isn't accepted, it is free'd | |
420 | * from the tcp listener sockets request queue, linked | |
421 | * from req->sk. The tcp socket is released. | |
422 | * This calls the ULP release function which will | |
423 | * also remove the mptcp socket, via | |
424 | * sock_put(ctx->conn). | |
425 | * | |
7ee24926 PA |
426 | * Problem is that the mptcp socket will be in |
427 | * ESTABLISHED state and will not have the SOCK_DEAD flag. | |
df1036da FW |
428 | * Both result in warnings from inet_sock_destruct. |
429 | */ | |
430 | ||
7ee24926 | 431 | if (sk->sk_state == TCP_ESTABLISHED) { |
df1036da FW |
432 | sk->sk_state = TCP_CLOSE; |
433 | WARN_ON_ONCE(sk->sk_socket); | |
434 | sock_orphan(sk); | |
435 | } | |
436 | ||
2c5ebd00 | 437 | mptcp_token_destroy(mptcp_sk(sk)); |
df1036da FW |
438 | inet_sock_destruct(sk); |
439 | } | |
440 | ||
9f5ca6a5 FW |
441 | static void mptcp_force_close(struct sock *sk) |
442 | { | |
443 | inet_sk_state_store(sk, TCP_CLOSE); | |
444 | sk_common_release(sk); | |
445 | } | |
446 | ||
4c8941de PA |
447 | static void subflow_ulp_fallback(struct sock *sk, |
448 | struct mptcp_subflow_context *old_ctx) | |
449 | { | |
450 | struct inet_connection_sock *icsk = inet_csk(sk); | |
451 | ||
452 | mptcp_subflow_tcp_fallback(sk, old_ctx); | |
453 | icsk->icsk_ulp_ops = NULL; | |
454 | rcu_assign_pointer(icsk->icsk_ulp_data, NULL); | |
455 | tcp_sk(sk)->is_mptcp = 0; | |
456 | } | |
457 | ||
39884604 PA |
458 | static void subflow_drop_ctx(struct sock *ssk) |
459 | { | |
460 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); | |
461 | ||
462 | if (!ctx) | |
463 | return; | |
464 | ||
465 | subflow_ulp_fallback(ssk, ctx); | |
466 | if (ctx->conn) | |
467 | sock_put(ctx->conn); | |
468 | ||
469 | kfree_rcu(ctx, rcu); | |
470 | } | |
471 | ||
b93df08c PA |
472 | void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow, |
473 | struct mptcp_options_received *mp_opt) | |
474 | { | |
475 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
476 | ||
477 | subflow->remote_key = mp_opt->sndr_key; | |
478 | subflow->fully_established = 1; | |
479 | subflow->can_ack = 1; | |
480 | WRITE_ONCE(msk->fully_established, true); | |
481 | } | |
482 | ||
cec37a6e PK |
483 | static struct sock *subflow_syn_recv_sock(const struct sock *sk, |
484 | struct sk_buff *skb, | |
485 | struct request_sock *req, | |
486 | struct dst_entry *dst, | |
487 | struct request_sock *req_unhash, | |
488 | bool *own_req) | |
489 | { | |
490 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk); | |
cc7972ea | 491 | struct mptcp_subflow_request_sock *subflow_req; |
cfde141e | 492 | struct mptcp_options_received mp_opt; |
9e365ff5 | 493 | bool fallback, fallback_is_fatal; |
58b09919 | 494 | struct sock *new_msk = NULL; |
cec37a6e PK |
495 | struct sock *child; |
496 | ||
497 | pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn); | |
498 | ||
9e365ff5 PA |
499 | /* After child creation we must look for 'mp_capable' even when options |
500 | * are not parsed | |
cfde141e PA |
501 | */ |
502 | mp_opt.mp_capable = 0; | |
9e365ff5 PA |
503 | |
504 | /* hopefully temporary handling for MP_JOIN+syncookie */ | |
505 | subflow_req = mptcp_subflow_rsk(req); | |
b7514694 | 506 | fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join; |
9e365ff5 PA |
507 | fallback = !tcp_rsk(req)->is_mptcp; |
508 | if (fallback) | |
ae2dd716 FW |
509 | goto create_child; |
510 | ||
d22f4988 | 511 | /* if the sk is MP_CAPABLE, we try to fetch the client key */ |
cc7972ea | 512 | if (subflow_req->mp_capable) { |
d22f4988 CP |
513 | if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) { |
514 | /* here we can receive and accept an in-window, | |
515 | * out-of-order pkt, which will not carry the MP_CAPABLE | |
516 | * opt even on mptcp enabled paths | |
517 | */ | |
58b09919 | 518 | goto create_msk; |
d22f4988 CP |
519 | } |
520 | ||
cfde141e PA |
521 | mptcp_get_options(skb, &mp_opt); |
522 | if (!mp_opt.mp_capable) { | |
4c8941de | 523 | fallback = true; |
58b09919 | 524 | goto create_child; |
d22f4988 | 525 | } |
58b09919 PA |
526 | |
527 | create_msk: | |
cfde141e | 528 | new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req); |
58b09919 | 529 | if (!new_msk) |
4c8941de | 530 | fallback = true; |
f296234c | 531 | } else if (subflow_req->mp_join) { |
cfde141e PA |
532 | mptcp_get_options(skb, &mp_opt); |
533 | if (!mp_opt.mp_join || | |
4cf8b7e4 | 534 | !mptcp_can_accept_new_subflow(subflow_req->msk) || |
cfde141e | 535 | !subflow_hmac_valid(req, &mp_opt)) { |
fc518953 | 536 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); |
9e365ff5 | 537 | fallback = true; |
fc518953 | 538 | } |
cc7972ea | 539 | } |
cec37a6e | 540 | |
d22f4988 | 541 | create_child: |
cec37a6e PK |
542 | child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, |
543 | req_unhash, own_req); | |
544 | ||
545 | if (child && *own_req) { | |
79c0949e PK |
546 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child); |
547 | ||
90bf4513 PA |
548 | tcp_rsk(req)->drop_req = false; |
549 | ||
4c8941de PA |
550 | /* we need to fallback on ctx allocation failure and on pre-reqs |
551 | * checking above. In the latter scenario we additionally need | |
552 | * to reset the context to non MPTCP status. | |
79c0949e | 553 | */ |
4c8941de | 554 | if (!ctx || fallback) { |
f296234c | 555 | if (fallback_is_fatal) |
729cd643 | 556 | goto dispose_child; |
4c8941de | 557 | |
39884604 | 558 | subflow_drop_ctx(child); |
58b09919 | 559 | goto out; |
f296234c | 560 | } |
79c0949e PK |
561 | |
562 | if (ctx->mp_capable) { | |
b93df08c PA |
563 | /* this can't race with mptcp_close(), as the msk is |
564 | * not yet exposted to user-space | |
565 | */ | |
566 | inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED); | |
567 | ||
58b09919 PA |
568 | /* new mpc subflow takes ownership of the newly |
569 | * created mptcp socket | |
570 | */ | |
df1036da | 571 | new_msk->sk_destruct = mptcp_sock_destruct; |
1b1c7a0e | 572 | mptcp_pm_new_connection(mptcp_sk(new_msk), 1); |
2c5ebd00 | 573 | mptcp_token_accept(subflow_req, mptcp_sk(new_msk)); |
58b09919 PA |
574 | ctx->conn = new_msk; |
575 | new_msk = NULL; | |
fca5c82c PA |
576 | |
577 | /* with OoO packets we can reach here without ingress | |
578 | * mpc option | |
579 | */ | |
b93df08c PA |
580 | if (mp_opt.mp_capable) |
581 | mptcp_subflow_fully_established(ctx, &mp_opt); | |
f296234c PK |
582 | } else if (ctx->mp_join) { |
583 | struct mptcp_sock *owner; | |
584 | ||
8fd4de12 | 585 | owner = subflow_req->msk; |
f296234c | 586 | if (!owner) |
729cd643 | 587 | goto dispose_child; |
f296234c | 588 | |
8fd4de12 PA |
589 | /* move the msk reference ownership to the subflow */ |
590 | subflow_req->msk = NULL; | |
f296234c PK |
591 | ctx->conn = (struct sock *)owner; |
592 | if (!mptcp_finish_join(child)) | |
729cd643 | 593 | goto dispose_child; |
fc518953 FW |
594 | |
595 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX); | |
90bf4513 | 596 | tcp_rsk(req)->drop_req = true; |
cec37a6e PK |
597 | } |
598 | } | |
599 | ||
58b09919 PA |
600 | out: |
601 | /* dispose of the left over mptcp master, if any */ | |
602 | if (unlikely(new_msk)) | |
9f5ca6a5 | 603 | mptcp_force_close(new_msk); |
4c8941de PA |
604 | |
605 | /* check for expected invariant - should never trigger, just help | |
606 | * catching eariler subtle bugs | |
607 | */ | |
ac2b47fb | 608 | WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp && |
4c8941de PA |
609 | (!mptcp_subflow_ctx(child) || |
610 | !mptcp_subflow_ctx(child)->conn)); | |
cec37a6e | 611 | return child; |
f296234c | 612 | |
729cd643 | 613 | dispose_child: |
39884604 | 614 | subflow_drop_ctx(child); |
729cd643 | 615 | tcp_rsk(req)->drop_req = true; |
729cd643 | 616 | inet_csk_prepare_for_destroy_sock(child); |
f296234c | 617 | tcp_done(child); |
97e61751 | 618 | req->rsk_ops->send_reset(sk, skb); |
729cd643 PA |
619 | |
620 | /* The last child reference will be released by the caller */ | |
621 | return child; | |
cec37a6e PK |
622 | } |
623 | ||
624 | static struct inet_connection_sock_af_ops subflow_specific; | |
625 | ||
648ef4b8 MM |
626 | enum mapping_status { |
627 | MAPPING_OK, | |
628 | MAPPING_INVALID, | |
629 | MAPPING_EMPTY, | |
e1ff9e82 DC |
630 | MAPPING_DATA_FIN, |
631 | MAPPING_DUMMY | |
648ef4b8 MM |
632 | }; |
633 | ||
634 | static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq) | |
635 | { | |
636 | if ((u32)seq == (u32)old_seq) | |
637 | return old_seq; | |
638 | ||
639 | /* Assume map covers data not mapped yet. */ | |
640 | return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32)); | |
641 | } | |
642 | ||
643 | static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) | |
644 | { | |
645 | WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d", | |
646 | ssn, subflow->map_subflow_seq, subflow->map_data_len); | |
647 | } | |
648 | ||
649 | static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) | |
650 | { | |
651 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
652 | unsigned int skb_consumed; | |
653 | ||
654 | skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; | |
655 | if (WARN_ON_ONCE(skb_consumed >= skb->len)) | |
656 | return true; | |
657 | ||
658 | return skb->len - skb_consumed <= subflow->map_data_len - | |
659 | mptcp_subflow_get_map_offset(subflow); | |
660 | } | |
661 | ||
662 | static bool validate_mapping(struct sock *ssk, struct sk_buff *skb) | |
663 | { | |
664 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
665 | u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; | |
666 | ||
667 | if (unlikely(before(ssn, subflow->map_subflow_seq))) { | |
668 | /* Mapping covers data later in the subflow stream, | |
669 | * currently unsupported. | |
670 | */ | |
671 | warn_bad_map(subflow, ssn); | |
672 | return false; | |
673 | } | |
674 | if (unlikely(!before(ssn, subflow->map_subflow_seq + | |
675 | subflow->map_data_len))) { | |
676 | /* Mapping does covers past subflow data, invalid */ | |
677 | warn_bad_map(subflow, ssn + skb->len); | |
678 | return false; | |
679 | } | |
680 | return true; | |
681 | } | |
682 | ||
43b54c6e MM |
683 | static enum mapping_status get_mapping_status(struct sock *ssk, |
684 | struct mptcp_sock *msk) | |
648ef4b8 MM |
685 | { |
686 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
687 | struct mptcp_ext *mpext; | |
688 | struct sk_buff *skb; | |
689 | u16 data_len; | |
690 | u64 map_seq; | |
691 | ||
692 | skb = skb_peek(&ssk->sk_receive_queue); | |
693 | if (!skb) | |
694 | return MAPPING_EMPTY; | |
695 | ||
e1ff9e82 DC |
696 | if (mptcp_check_fallback(ssk)) |
697 | return MAPPING_DUMMY; | |
698 | ||
648ef4b8 MM |
699 | mpext = mptcp_get_ext(skb); |
700 | if (!mpext || !mpext->use_map) { | |
701 | if (!subflow->map_valid && !skb->len) { | |
702 | /* the TCP stack deliver 0 len FIN pkt to the receive | |
703 | * queue, that is the only 0len pkts ever expected here, | |
704 | * and we can admit no mapping only for 0 len pkts | |
705 | */ | |
706 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) | |
707 | WARN_ONCE(1, "0len seq %d:%d flags %x", | |
708 | TCP_SKB_CB(skb)->seq, | |
709 | TCP_SKB_CB(skb)->end_seq, | |
710 | TCP_SKB_CB(skb)->tcp_flags); | |
711 | sk_eat_skb(ssk, skb); | |
712 | return MAPPING_EMPTY; | |
713 | } | |
714 | ||
715 | if (!subflow->map_valid) | |
716 | return MAPPING_INVALID; | |
717 | ||
718 | goto validate_seq; | |
719 | } | |
720 | ||
721 | pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d", | |
722 | mpext->data_seq, mpext->dsn64, mpext->subflow_seq, | |
723 | mpext->data_len, mpext->data_fin); | |
724 | ||
725 | data_len = mpext->data_len; | |
726 | if (data_len == 0) { | |
727 | pr_err("Infinite mapping not handled"); | |
fc518953 | 728 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX); |
648ef4b8 MM |
729 | return MAPPING_INVALID; |
730 | } | |
731 | ||
732 | if (mpext->data_fin == 1) { | |
733 | if (data_len == 1) { | |
1a49b2c2 MM |
734 | bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq, |
735 | mpext->dsn64); | |
43b54c6e | 736 | pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq); |
648ef4b8 MM |
737 | if (subflow->map_valid) { |
738 | /* A DATA_FIN might arrive in a DSS | |
739 | * option before the previous mapping | |
740 | * has been fully consumed. Continue | |
741 | * handling the existing mapping. | |
742 | */ | |
743 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
744 | return MAPPING_OK; | |
745 | } else { | |
ef59b195 MM |
746 | if (updated && schedule_work(&msk->work)) |
747 | sock_hold((struct sock *)msk); | |
748 | ||
648ef4b8 MM |
749 | return MAPPING_DATA_FIN; |
750 | } | |
43b54c6e | 751 | } else { |
017512a0 | 752 | u64 data_fin_seq = mpext->data_seq + data_len - 1; |
1a49b2c2 MM |
753 | |
754 | /* If mpext->data_seq is a 32-bit value, data_fin_seq | |
755 | * must also be limited to 32 bits. | |
756 | */ | |
757 | if (!mpext->dsn64) | |
758 | data_fin_seq &= GENMASK_ULL(31, 0); | |
759 | ||
760 | mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64); | |
761 | pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d", | |
762 | data_fin_seq, mpext->dsn64); | |
648ef4b8 MM |
763 | } |
764 | ||
765 | /* Adjust for DATA_FIN using 1 byte of sequence space */ | |
766 | data_len--; | |
767 | } | |
768 | ||
769 | if (!mpext->dsn64) { | |
770 | map_seq = expand_seq(subflow->map_seq, subflow->map_data_len, | |
771 | mpext->data_seq); | |
a0c1d0ea | 772 | subflow->use_64bit_ack = 0; |
648ef4b8 MM |
773 | pr_debug("expanded seq=%llu", subflow->map_seq); |
774 | } else { | |
775 | map_seq = mpext->data_seq; | |
a0c1d0ea | 776 | subflow->use_64bit_ack = 1; |
648ef4b8 MM |
777 | } |
778 | ||
779 | if (subflow->map_valid) { | |
780 | /* Allow replacing only with an identical map */ | |
781 | if (subflow->map_seq == map_seq && | |
782 | subflow->map_subflow_seq == mpext->subflow_seq && | |
783 | subflow->map_data_len == data_len) { | |
784 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
785 | return MAPPING_OK; | |
786 | } | |
787 | ||
788 | /* If this skb data are fully covered by the current mapping, | |
789 | * the new map would need caching, which is not supported | |
790 | */ | |
fc518953 FW |
791 | if (skb_is_fully_mapped(ssk, skb)) { |
792 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH); | |
648ef4b8 | 793 | return MAPPING_INVALID; |
fc518953 | 794 | } |
648ef4b8 MM |
795 | |
796 | /* will validate the next map after consuming the current one */ | |
797 | return MAPPING_OK; | |
798 | } | |
799 | ||
800 | subflow->map_seq = map_seq; | |
801 | subflow->map_subflow_seq = mpext->subflow_seq; | |
802 | subflow->map_data_len = data_len; | |
803 | subflow->map_valid = 1; | |
d22f4988 | 804 | subflow->mpc_map = mpext->mpc_map; |
648ef4b8 MM |
805 | pr_debug("new map seq=%llu subflow_seq=%u data_len=%u", |
806 | subflow->map_seq, subflow->map_subflow_seq, | |
807 | subflow->map_data_len); | |
808 | ||
809 | validate_seq: | |
810 | /* we revalidate valid mapping on new skb, because we must ensure | |
811 | * the current skb is completely covered by the available mapping | |
812 | */ | |
813 | if (!validate_mapping(ssk, skb)) | |
814 | return MAPPING_INVALID; | |
815 | ||
816 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
817 | return MAPPING_OK; | |
818 | } | |
819 | ||
bfae9dae FW |
820 | static int subflow_read_actor(read_descriptor_t *desc, |
821 | struct sk_buff *skb, | |
822 | unsigned int offset, size_t len) | |
823 | { | |
824 | size_t copy_len = min(desc->count, len); | |
825 | ||
826 | desc->count -= copy_len; | |
827 | ||
828 | pr_debug("flushed %zu bytes, %zu left", copy_len, desc->count); | |
829 | return copy_len; | |
830 | } | |
831 | ||
648ef4b8 MM |
832 | static bool subflow_check_data_avail(struct sock *ssk) |
833 | { | |
834 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
835 | enum mapping_status status; | |
836 | struct mptcp_sock *msk; | |
837 | struct sk_buff *skb; | |
838 | ||
839 | pr_debug("msk=%p ssk=%p data_avail=%d skb=%p", subflow->conn, ssk, | |
840 | subflow->data_avail, skb_peek(&ssk->sk_receive_queue)); | |
841 | if (subflow->data_avail) | |
842 | return true; | |
843 | ||
648ef4b8 MM |
844 | msk = mptcp_sk(subflow->conn); |
845 | for (;;) { | |
846 | u32 map_remaining; | |
847 | size_t delta; | |
848 | u64 ack_seq; | |
849 | u64 old_ack; | |
850 | ||
43b54c6e | 851 | status = get_mapping_status(ssk, msk); |
648ef4b8 MM |
852 | pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status); |
853 | if (status == MAPPING_INVALID) { | |
854 | ssk->sk_err = EBADMSG; | |
855 | goto fatal; | |
856 | } | |
e1ff9e82 DC |
857 | if (status == MAPPING_DUMMY) { |
858 | __mptcp_do_fallback(msk); | |
859 | skb = skb_peek(&ssk->sk_receive_queue); | |
860 | subflow->map_valid = 1; | |
861 | subflow->map_seq = READ_ONCE(msk->ack_seq); | |
862 | subflow->map_data_len = skb->len; | |
863 | subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - | |
864 | subflow->ssn_offset; | |
865 | return true; | |
866 | } | |
648ef4b8 MM |
867 | |
868 | if (status != MAPPING_OK) | |
869 | return false; | |
870 | ||
871 | skb = skb_peek(&ssk->sk_receive_queue); | |
872 | if (WARN_ON_ONCE(!skb)) | |
873 | return false; | |
874 | ||
d22f4988 CP |
875 | /* if msk lacks the remote key, this subflow must provide an |
876 | * MP_CAPABLE-based mapping | |
877 | */ | |
878 | if (unlikely(!READ_ONCE(msk->can_ack))) { | |
879 | if (!subflow->mpc_map) { | |
880 | ssk->sk_err = EBADMSG; | |
881 | goto fatal; | |
882 | } | |
883 | WRITE_ONCE(msk->remote_key, subflow->remote_key); | |
884 | WRITE_ONCE(msk->ack_seq, subflow->map_seq); | |
885 | WRITE_ONCE(msk->can_ack, true); | |
886 | } | |
887 | ||
648ef4b8 MM |
888 | old_ack = READ_ONCE(msk->ack_seq); |
889 | ack_seq = mptcp_subflow_get_mapped_dsn(subflow); | |
890 | pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack, | |
891 | ack_seq); | |
892 | if (ack_seq == old_ack) | |
893 | break; | |
894 | ||
895 | /* only accept in-sequence mapping. Old values are spurious | |
896 | * retransmission; we can hit "future" values on active backup | |
897 | * subflow switch, we relay on retransmissions to get | |
898 | * in-sequence data. | |
899 | * Cuncurrent subflows support will require subflow data | |
900 | * reordering | |
901 | */ | |
902 | map_remaining = subflow->map_data_len - | |
903 | mptcp_subflow_get_map_offset(subflow); | |
904 | if (before64(ack_seq, old_ack)) | |
905 | delta = min_t(size_t, old_ack - ack_seq, map_remaining); | |
906 | else | |
907 | delta = min_t(size_t, ack_seq - old_ack, map_remaining); | |
908 | ||
909 | /* discard mapped data */ | |
910 | pr_debug("discarding %zu bytes, current map len=%d", delta, | |
911 | map_remaining); | |
912 | if (delta) { | |
648ef4b8 MM |
913 | read_descriptor_t desc = { |
914 | .count = delta, | |
648ef4b8 MM |
915 | }; |
916 | int ret; | |
917 | ||
bfae9dae | 918 | ret = tcp_read_sock(ssk, &desc, subflow_read_actor); |
648ef4b8 MM |
919 | if (ret < 0) { |
920 | ssk->sk_err = -ret; | |
921 | goto fatal; | |
922 | } | |
923 | if (ret < delta) | |
924 | return false; | |
925 | if (delta == map_remaining) | |
926 | subflow->map_valid = 0; | |
927 | } | |
928 | } | |
929 | return true; | |
930 | ||
931 | fatal: | |
932 | /* fatal protocol error, close the socket */ | |
933 | /* This barrier is coupled with smp_rmb() in tcp_poll() */ | |
934 | smp_wmb(); | |
935 | ssk->sk_error_report(ssk); | |
936 | tcp_set_state(ssk, TCP_CLOSE); | |
937 | tcp_send_active_reset(ssk, GFP_ATOMIC); | |
938 | return false; | |
939 | } | |
940 | ||
941 | bool mptcp_subflow_data_available(struct sock *sk) | |
942 | { | |
943 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
944 | struct sk_buff *skb; | |
945 | ||
946 | /* check if current mapping is still valid */ | |
947 | if (subflow->map_valid && | |
948 | mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) { | |
949 | subflow->map_valid = 0; | |
950 | subflow->data_avail = 0; | |
951 | ||
952 | pr_debug("Done with mapping: seq=%u data_len=%u", | |
953 | subflow->map_subflow_seq, | |
954 | subflow->map_data_len); | |
955 | } | |
956 | ||
957 | if (!subflow_check_data_avail(sk)) { | |
958 | subflow->data_avail = 0; | |
959 | return false; | |
960 | } | |
961 | ||
962 | skb = skb_peek(&sk->sk_receive_queue); | |
963 | subflow->data_avail = skb && | |
964 | before(tcp_sk(sk)->copied_seq, TCP_SKB_CB(skb)->end_seq); | |
965 | return subflow->data_avail; | |
966 | } | |
967 | ||
071c8ed6 FW |
968 | /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy, |
969 | * not the ssk one. | |
970 | * | |
971 | * In mptcp, rwin is about the mptcp-level connection data. | |
972 | * | |
973 | * Data that is still on the ssk rx queue can thus be ignored, | |
974 | * as far as mptcp peer is concerened that data is still inflight. | |
975 | * DSS ACK is updated when skb is moved to the mptcp rx queue. | |
976 | */ | |
977 | void mptcp_space(const struct sock *ssk, int *space, int *full_space) | |
978 | { | |
979 | const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
980 | const struct sock *sk = subflow->conn; | |
981 | ||
982 | *space = tcp_space(sk); | |
983 | *full_space = tcp_full_space(sk); | |
984 | } | |
985 | ||
648ef4b8 MM |
986 | static void subflow_data_ready(struct sock *sk) |
987 | { | |
988 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
8c728940 | 989 | u16 state = 1 << inet_sk_state_load(sk); |
648ef4b8 | 990 | struct sock *parent = subflow->conn; |
e1ff9e82 | 991 | struct mptcp_sock *msk; |
648ef4b8 | 992 | |
e1ff9e82 | 993 | msk = mptcp_sk(parent); |
8c728940 | 994 | if (state & TCPF_LISTEN) { |
e1ff9e82 | 995 | set_bit(MPTCP_DATA_READY, &msk->flags); |
dc093db5 | 996 | parent->sk_data_ready(parent); |
648ef4b8 MM |
997 | return; |
998 | } | |
999 | ||
e1ff9e82 | 1000 | WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable && |
8c728940 | 1001 | !subflow->mp_join && !(state & TCPF_CLOSE)); |
e1ff9e82 | 1002 | |
101f6f85 | 1003 | if (mptcp_subflow_data_available(sk)) |
2e52213c | 1004 | mptcp_data_ready(parent, sk); |
648ef4b8 MM |
1005 | } |
1006 | ||
1007 | static void subflow_write_space(struct sock *sk) | |
1008 | { | |
1009 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
1010 | struct sock *parent = subflow->conn; | |
1011 | ||
1012 | sk_stream_write_space(sk); | |
dc093db5 | 1013 | if (sk_stream_is_writeable(sk)) { |
1891c4a0 FW |
1014 | set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags); |
1015 | smp_mb__after_atomic(); | |
1016 | /* set SEND_SPACE before sk_stream_write_space clears NOSPACE */ | |
648ef4b8 MM |
1017 | sk_stream_write_space(parent); |
1018 | } | |
1019 | } | |
1020 | ||
cec37a6e PK |
1021 | static struct inet_connection_sock_af_ops * |
1022 | subflow_default_af_ops(struct sock *sk) | |
1023 | { | |
1024 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1025 | if (sk->sk_family == AF_INET6) | |
1026 | return &subflow_v6_specific; | |
1027 | #endif | |
1028 | return &subflow_specific; | |
1029 | } | |
1030 | ||
cec37a6e | 1031 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
31484d56 GU |
1032 | void mptcpv6_handle_mapped(struct sock *sk, bool mapped) |
1033 | { | |
cec37a6e PK |
1034 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
1035 | struct inet_connection_sock *icsk = inet_csk(sk); | |
1036 | struct inet_connection_sock_af_ops *target; | |
1037 | ||
1038 | target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk); | |
1039 | ||
1040 | pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d", | |
edc7e489 | 1041 | subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped); |
cec37a6e PK |
1042 | |
1043 | if (likely(icsk->icsk_af_ops == target)) | |
1044 | return; | |
1045 | ||
1046 | subflow->icsk_af_ops = icsk->icsk_af_ops; | |
1047 | icsk->icsk_af_ops = target; | |
cec37a6e | 1048 | } |
31484d56 | 1049 | #endif |
cec37a6e | 1050 | |
ec3edaa7 PK |
1051 | static void mptcp_info2sockaddr(const struct mptcp_addr_info *info, |
1052 | struct sockaddr_storage *addr) | |
1053 | { | |
1054 | memset(addr, 0, sizeof(*addr)); | |
1055 | addr->ss_family = info->family; | |
1056 | if (addr->ss_family == AF_INET) { | |
1057 | struct sockaddr_in *in_addr = (struct sockaddr_in *)addr; | |
1058 | ||
1059 | in_addr->sin_addr = info->addr; | |
1060 | in_addr->sin_port = info->port; | |
1061 | } | |
1062 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1063 | else if (addr->ss_family == AF_INET6) { | |
1064 | struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr; | |
1065 | ||
1066 | in6_addr->sin6_addr = info->addr6; | |
1067 | in6_addr->sin6_port = info->port; | |
1068 | } | |
1069 | #endif | |
1070 | } | |
1071 | ||
1072 | int __mptcp_subflow_connect(struct sock *sk, int ifindex, | |
1073 | const struct mptcp_addr_info *loc, | |
1074 | const struct mptcp_addr_info *remote) | |
1075 | { | |
1076 | struct mptcp_sock *msk = mptcp_sk(sk); | |
1077 | struct mptcp_subflow_context *subflow; | |
1078 | struct sockaddr_storage addr; | |
2ff0e566 | 1079 | int remote_id = remote->id; |
6bad912b | 1080 | int local_id = loc->id; |
ec3edaa7 | 1081 | struct socket *sf; |
6bad912b | 1082 | struct sock *ssk; |
ec3edaa7 PK |
1083 | u32 remote_token; |
1084 | int addrlen; | |
1085 | int err; | |
1086 | ||
b93df08c | 1087 | if (!mptcp_is_fully_established(sk)) |
ec3edaa7 PK |
1088 | return -ENOTCONN; |
1089 | ||
1090 | err = mptcp_subflow_create_socket(sk, &sf); | |
1091 | if (err) | |
1092 | return err; | |
1093 | ||
6bad912b PA |
1094 | ssk = sf->sk; |
1095 | subflow = mptcp_subflow_ctx(ssk); | |
1096 | do { | |
1097 | get_random_bytes(&subflow->local_nonce, sizeof(u32)); | |
1098 | } while (!subflow->local_nonce); | |
1099 | ||
1100 | if (!local_id) { | |
1101 | err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk); | |
1102 | if (err < 0) | |
1103 | goto failed; | |
1104 | ||
1105 | local_id = err; | |
1106 | } | |
1107 | ||
ec3edaa7 PK |
1108 | subflow->remote_key = msk->remote_key; |
1109 | subflow->local_key = msk->local_key; | |
1110 | subflow->token = msk->token; | |
1111 | mptcp_info2sockaddr(loc, &addr); | |
1112 | ||
1113 | addrlen = sizeof(struct sockaddr_in); | |
1114 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1115 | if (loc->family == AF_INET6) | |
1116 | addrlen = sizeof(struct sockaddr_in6); | |
1117 | #endif | |
6bad912b | 1118 | ssk->sk_bound_dev_if = ifindex; |
ec3edaa7 PK |
1119 | err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen); |
1120 | if (err) | |
1121 | goto failed; | |
1122 | ||
1123 | mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL); | |
2ff0e566 GT |
1124 | pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk, |
1125 | remote_token, local_id, remote_id); | |
ec3edaa7 | 1126 | subflow->remote_token = remote_token; |
6bad912b | 1127 | subflow->local_id = local_id; |
2ff0e566 | 1128 | subflow->remote_id = remote_id; |
ec3edaa7 PK |
1129 | subflow->request_join = 1; |
1130 | subflow->request_bkup = 1; | |
1131 | mptcp_info2sockaddr(remote, &addr); | |
1132 | ||
1133 | err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK); | |
1134 | if (err && err != -EINPROGRESS) | |
1135 | goto failed; | |
1136 | ||
1137 | spin_lock_bh(&msk->join_list_lock); | |
1138 | list_add_tail(&subflow->node, &msk->join_list); | |
1139 | spin_unlock_bh(&msk->join_list_lock); | |
1140 | ||
1141 | return err; | |
1142 | ||
1143 | failed: | |
1144 | sock_release(sf); | |
1145 | return err; | |
1146 | } | |
1147 | ||
2303f994 PK |
1148 | int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock) |
1149 | { | |
1150 | struct mptcp_subflow_context *subflow; | |
1151 | struct net *net = sock_net(sk); | |
1152 | struct socket *sf; | |
1153 | int err; | |
1154 | ||
adf73410 PA |
1155 | /* un-accepted server sockets can reach here - on bad configuration |
1156 | * bail early to avoid greater trouble later | |
1157 | */ | |
1158 | if (unlikely(!sk->sk_socket)) | |
1159 | return -EINVAL; | |
1160 | ||
cec37a6e PK |
1161 | err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP, |
1162 | &sf); | |
2303f994 PK |
1163 | if (err) |
1164 | return err; | |
1165 | ||
1166 | lock_sock(sf->sk); | |
1167 | ||
1168 | /* kernel sockets do not by default acquire net ref, but TCP timer | |
1169 | * needs it. | |
1170 | */ | |
1171 | sf->sk->sk_net_refcnt = 1; | |
1172 | get_net(net); | |
f6f7d8cf | 1173 | #ifdef CONFIG_PROC_FS |
2303f994 | 1174 | this_cpu_add(*net->core.sock_inuse, 1); |
f6f7d8cf | 1175 | #endif |
2303f994 PK |
1176 | err = tcp_set_ulp(sf->sk, "mptcp"); |
1177 | release_sock(sf->sk); | |
1178 | ||
b8ad540d WY |
1179 | if (err) { |
1180 | sock_release(sf); | |
2303f994 | 1181 | return err; |
b8ad540d | 1182 | } |
2303f994 | 1183 | |
7d14b0d2 PA |
1184 | /* the newly created socket really belongs to the owning MPTCP master |
1185 | * socket, even if for additional subflows the allocation is performed | |
1186 | * by a kernel workqueue. Adjust inode references, so that the | |
1187 | * procfs/diag interaces really show this one belonging to the correct | |
1188 | * user. | |
1189 | */ | |
1190 | SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino; | |
1191 | SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid; | |
1192 | SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid; | |
1193 | ||
2303f994 PK |
1194 | subflow = mptcp_subflow_ctx(sf->sk); |
1195 | pr_debug("subflow=%p", subflow); | |
1196 | ||
1197 | *new_sock = sf; | |
79c0949e | 1198 | sock_hold(sk); |
2303f994 PK |
1199 | subflow->conn = sk; |
1200 | ||
1201 | return 0; | |
1202 | } | |
1203 | ||
1204 | static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk, | |
1205 | gfp_t priority) | |
1206 | { | |
1207 | struct inet_connection_sock *icsk = inet_csk(sk); | |
1208 | struct mptcp_subflow_context *ctx; | |
1209 | ||
1210 | ctx = kzalloc(sizeof(*ctx), priority); | |
1211 | if (!ctx) | |
1212 | return NULL; | |
1213 | ||
1214 | rcu_assign_pointer(icsk->icsk_ulp_data, ctx); | |
cec37a6e | 1215 | INIT_LIST_HEAD(&ctx->node); |
2303f994 PK |
1216 | |
1217 | pr_debug("subflow=%p", ctx); | |
1218 | ||
1219 | ctx->tcp_sock = sk; | |
1220 | ||
1221 | return ctx; | |
1222 | } | |
1223 | ||
648ef4b8 MM |
1224 | static void __subflow_state_change(struct sock *sk) |
1225 | { | |
1226 | struct socket_wq *wq; | |
1227 | ||
1228 | rcu_read_lock(); | |
1229 | wq = rcu_dereference(sk->sk_wq); | |
1230 | if (skwq_has_sleeper(wq)) | |
1231 | wake_up_interruptible_all(&wq->wait); | |
1232 | rcu_read_unlock(); | |
1233 | } | |
1234 | ||
1235 | static bool subflow_is_done(const struct sock *sk) | |
1236 | { | |
1237 | return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE; | |
1238 | } | |
1239 | ||
1240 | static void subflow_state_change(struct sock *sk) | |
1241 | { | |
1242 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
dc093db5 | 1243 | struct sock *parent = subflow->conn; |
648ef4b8 MM |
1244 | |
1245 | __subflow_state_change(sk); | |
1246 | ||
8fd73804 DC |
1247 | if (subflow_simultaneous_connect(sk)) { |
1248 | mptcp_do_fallback(sk); | |
a6b118fe | 1249 | mptcp_rcv_space_init(mptcp_sk(parent), sk); |
8fd73804 DC |
1250 | pr_fallback(mptcp_sk(parent)); |
1251 | subflow->conn_finished = 1; | |
1252 | if (inet_sk_state_load(parent) == TCP_SYN_SENT) { | |
1253 | inet_sk_state_store(parent, TCP_ESTABLISHED); | |
1254 | parent->sk_state_change(parent); | |
1255 | } | |
1256 | } | |
1257 | ||
648ef4b8 MM |
1258 | /* as recvmsg() does not acquire the subflow socket for ssk selection |
1259 | * a fin packet carrying a DSS can be unnoticed if we don't trigger | |
1260 | * the data available machinery here. | |
1261 | */ | |
e1ff9e82 | 1262 | if (mptcp_subflow_data_available(sk)) |
2e52213c | 1263 | mptcp_data_ready(parent, sk); |
648ef4b8 | 1264 | |
067a0b3d MM |
1265 | if (__mptcp_check_fallback(mptcp_sk(parent)) && |
1266 | !(parent->sk_shutdown & RCV_SHUTDOWN) && | |
648ef4b8 MM |
1267 | !subflow->rx_eof && subflow_is_done(sk)) { |
1268 | subflow->rx_eof = 1; | |
59832e24 | 1269 | mptcp_subflow_eof(parent); |
648ef4b8 MM |
1270 | } |
1271 | } | |
1272 | ||
2303f994 PK |
1273 | static int subflow_ulp_init(struct sock *sk) |
1274 | { | |
cec37a6e | 1275 | struct inet_connection_sock *icsk = inet_csk(sk); |
2303f994 PK |
1276 | struct mptcp_subflow_context *ctx; |
1277 | struct tcp_sock *tp = tcp_sk(sk); | |
1278 | int err = 0; | |
1279 | ||
1280 | /* disallow attaching ULP to a socket unless it has been | |
1281 | * created with sock_create_kern() | |
1282 | */ | |
1283 | if (!sk->sk_kern_sock) { | |
1284 | err = -EOPNOTSUPP; | |
1285 | goto out; | |
1286 | } | |
1287 | ||
1288 | ctx = subflow_create_ctx(sk, GFP_KERNEL); | |
1289 | if (!ctx) { | |
1290 | err = -ENOMEM; | |
1291 | goto out; | |
1292 | } | |
1293 | ||
1294 | pr_debug("subflow=%p, family=%d", ctx, sk->sk_family); | |
1295 | ||
1296 | tp->is_mptcp = 1; | |
cec37a6e PK |
1297 | ctx->icsk_af_ops = icsk->icsk_af_ops; |
1298 | icsk->icsk_af_ops = subflow_default_af_ops(sk); | |
648ef4b8 MM |
1299 | ctx->tcp_data_ready = sk->sk_data_ready; |
1300 | ctx->tcp_state_change = sk->sk_state_change; | |
1301 | ctx->tcp_write_space = sk->sk_write_space; | |
1302 | sk->sk_data_ready = subflow_data_ready; | |
1303 | sk->sk_write_space = subflow_write_space; | |
1304 | sk->sk_state_change = subflow_state_change; | |
2303f994 PK |
1305 | out: |
1306 | return err; | |
1307 | } | |
1308 | ||
1309 | static void subflow_ulp_release(struct sock *sk) | |
1310 | { | |
1311 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk); | |
1312 | ||
1313 | if (!ctx) | |
1314 | return; | |
1315 | ||
79c0949e PK |
1316 | if (ctx->conn) |
1317 | sock_put(ctx->conn); | |
1318 | ||
2303f994 PK |
1319 | kfree_rcu(ctx, rcu); |
1320 | } | |
1321 | ||
cec37a6e PK |
1322 | static void subflow_ulp_clone(const struct request_sock *req, |
1323 | struct sock *newsk, | |
1324 | const gfp_t priority) | |
1325 | { | |
1326 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
1327 | struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk); | |
1328 | struct mptcp_subflow_context *new_ctx; | |
1329 | ||
f296234c PK |
1330 | if (!tcp_rsk(req)->is_mptcp || |
1331 | (!subflow_req->mp_capable && !subflow_req->mp_join)) { | |
648ef4b8 | 1332 | subflow_ulp_fallback(newsk, old_ctx); |
cec37a6e PK |
1333 | return; |
1334 | } | |
1335 | ||
1336 | new_ctx = subflow_create_ctx(newsk, priority); | |
edc7e489 | 1337 | if (!new_ctx) { |
648ef4b8 | 1338 | subflow_ulp_fallback(newsk, old_ctx); |
cec37a6e PK |
1339 | return; |
1340 | } | |
1341 | ||
1342 | new_ctx->conn_finished = 1; | |
1343 | new_ctx->icsk_af_ops = old_ctx->icsk_af_ops; | |
648ef4b8 MM |
1344 | new_ctx->tcp_data_ready = old_ctx->tcp_data_ready; |
1345 | new_ctx->tcp_state_change = old_ctx->tcp_state_change; | |
1346 | new_ctx->tcp_write_space = old_ctx->tcp_write_space; | |
58b09919 PA |
1347 | new_ctx->rel_write_seq = 1; |
1348 | new_ctx->tcp_sock = newsk; | |
1349 | ||
f296234c PK |
1350 | if (subflow_req->mp_capable) { |
1351 | /* see comments in subflow_syn_recv_sock(), MPTCP connection | |
1352 | * is fully established only after we receive the remote key | |
1353 | */ | |
1354 | new_ctx->mp_capable = 1; | |
f296234c PK |
1355 | new_ctx->local_key = subflow_req->local_key; |
1356 | new_ctx->token = subflow_req->token; | |
1357 | new_ctx->ssn_offset = subflow_req->ssn_offset; | |
1358 | new_ctx->idsn = subflow_req->idsn; | |
1359 | } else if (subflow_req->mp_join) { | |
ec3edaa7 | 1360 | new_ctx->ssn_offset = subflow_req->ssn_offset; |
f296234c PK |
1361 | new_ctx->mp_join = 1; |
1362 | new_ctx->fully_established = 1; | |
1363 | new_ctx->backup = subflow_req->backup; | |
1364 | new_ctx->local_id = subflow_req->local_id; | |
2ff0e566 | 1365 | new_ctx->remote_id = subflow_req->remote_id; |
f296234c PK |
1366 | new_ctx->token = subflow_req->token; |
1367 | new_ctx->thmac = subflow_req->thmac; | |
1368 | } | |
cec37a6e PK |
1369 | } |
1370 | ||
2303f994 PK |
1371 | static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { |
1372 | .name = "mptcp", | |
1373 | .owner = THIS_MODULE, | |
1374 | .init = subflow_ulp_init, | |
1375 | .release = subflow_ulp_release, | |
cec37a6e | 1376 | .clone = subflow_ulp_clone, |
2303f994 PK |
1377 | }; |
1378 | ||
cec37a6e PK |
1379 | static int subflow_ops_init(struct request_sock_ops *subflow_ops) |
1380 | { | |
1381 | subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock); | |
1382 | subflow_ops->slab_name = "request_sock_subflow"; | |
1383 | ||
1384 | subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name, | |
1385 | subflow_ops->obj_size, 0, | |
1386 | SLAB_ACCOUNT | | |
1387 | SLAB_TYPESAFE_BY_RCU, | |
1388 | NULL); | |
1389 | if (!subflow_ops->slab) | |
1390 | return -ENOMEM; | |
1391 | ||
79c0949e PK |
1392 | subflow_ops->destructor = subflow_req_destructor; |
1393 | ||
cec37a6e PK |
1394 | return 0; |
1395 | } | |
1396 | ||
d39dceca | 1397 | void __init mptcp_subflow_init(void) |
2303f994 | 1398 | { |
08b8d080 FW |
1399 | mptcp_subflow_request_sock_ops = tcp_request_sock_ops; |
1400 | if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0) | |
cec37a6e PK |
1401 | panic("MPTCP: failed to init subflow request sock ops\n"); |
1402 | ||
1403 | subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops; | |
1404 | subflow_request_sock_ipv4_ops.init_req = subflow_v4_init_req; | |
1405 | ||
1406 | subflow_specific = ipv4_specific; | |
1407 | subflow_specific.conn_request = subflow_v4_conn_request; | |
1408 | subflow_specific.syn_recv_sock = subflow_syn_recv_sock; | |
1409 | subflow_specific.sk_rx_dst_set = subflow_finish_connect; | |
1410 | ||
1411 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1412 | subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; | |
1413 | subflow_request_sock_ipv6_ops.init_req = subflow_v6_init_req; | |
1414 | ||
1415 | subflow_v6_specific = ipv6_specific; | |
1416 | subflow_v6_specific.conn_request = subflow_v6_conn_request; | |
1417 | subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; | |
1418 | subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; | |
1419 | ||
1420 | subflow_v6m_specific = subflow_v6_specific; | |
1421 | subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; | |
1422 | subflow_v6m_specific.send_check = ipv4_specific.send_check; | |
1423 | subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; | |
1424 | subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; | |
1425 | subflow_v6m_specific.net_frag_header_len = 0; | |
1426 | #endif | |
1427 | ||
5147dfb5 DC |
1428 | mptcp_diag_subflow_init(&subflow_ulp_ops); |
1429 | ||
2303f994 PK |
1430 | if (tcp_register_ulp(&subflow_ulp_ops) != 0) |
1431 | panic("MPTCP: failed to register subflows to ULP\n"); | |
1432 | } |