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