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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> | |
12 | #include <net/sock.h> | |
13 | #include <net/inet_common.h> | |
14 | #include <net/inet_hashtables.h> | |
15 | #include <net/protocol.h> | |
16 | #include <net/tcp.h> | |
cec37a6e PK |
17 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
18 | #include <net/ip6_route.h> | |
19 | #endif | |
2303f994 PK |
20 | #include <net/mptcp.h> |
21 | #include "protocol.h" | |
22 | ||
79c0949e PK |
23 | static int subflow_rebuild_header(struct sock *sk) |
24 | { | |
25 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
26 | int err = 0; | |
27 | ||
28 | if (subflow->request_mptcp && !subflow->token) { | |
29 | pr_debug("subflow=%p", sk); | |
30 | err = mptcp_token_new_connect(sk); | |
31 | } | |
32 | ||
33 | if (err) | |
34 | return err; | |
35 | ||
36 | return subflow->icsk_af_ops->rebuild_header(sk); | |
37 | } | |
38 | ||
39 | static void subflow_req_destructor(struct request_sock *req) | |
40 | { | |
41 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
42 | ||
43 | pr_debug("subflow_req=%p", subflow_req); | |
44 | ||
45 | if (subflow_req->mp_capable) | |
46 | mptcp_token_destroy_request(subflow_req->token); | |
47 | tcp_request_sock_ops.destructor(req); | |
48 | } | |
49 | ||
cec37a6e PK |
50 | static void subflow_init_req(struct request_sock *req, |
51 | const struct sock *sk_listener, | |
52 | struct sk_buff *skb) | |
53 | { | |
54 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); | |
55 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
56 | struct tcp_options_received rx_opt; | |
57 | ||
58 | pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); | |
59 | ||
60 | memset(&rx_opt.mptcp, 0, sizeof(rx_opt.mptcp)); | |
61 | mptcp_get_options(skb, &rx_opt); | |
62 | ||
63 | subflow_req->mp_capable = 0; | |
d22f4988 | 64 | subflow_req->remote_key_valid = 0; |
cec37a6e PK |
65 | |
66 | #ifdef CONFIG_TCP_MD5SIG | |
67 | /* no MPTCP if MD5SIG is enabled on this socket or we may run out of | |
68 | * TCP option space. | |
69 | */ | |
70 | if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) | |
71 | return; | |
72 | #endif | |
73 | ||
74 | if (rx_opt.mptcp.mp_capable && listener->request_mptcp) { | |
79c0949e PK |
75 | int err; |
76 | ||
77 | err = mptcp_token_new_request(req); | |
78 | if (err == 0) | |
79 | subflow_req->mp_capable = 1; | |
80 | ||
648ef4b8 | 81 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
cec37a6e PK |
82 | } |
83 | } | |
84 | ||
85 | static void subflow_v4_init_req(struct request_sock *req, | |
86 | const struct sock *sk_listener, | |
87 | struct sk_buff *skb) | |
88 | { | |
89 | tcp_rsk(req)->is_mptcp = 1; | |
90 | ||
91 | tcp_request_sock_ipv4_ops.init_req(req, sk_listener, skb); | |
92 | ||
93 | subflow_init_req(req, sk_listener, skb); | |
94 | } | |
95 | ||
96 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
97 | static void subflow_v6_init_req(struct request_sock *req, | |
98 | const struct sock *sk_listener, | |
99 | struct sk_buff *skb) | |
100 | { | |
101 | tcp_rsk(req)->is_mptcp = 1; | |
102 | ||
103 | tcp_request_sock_ipv6_ops.init_req(req, sk_listener, skb); | |
104 | ||
105 | subflow_init_req(req, sk_listener, skb); | |
106 | } | |
107 | #endif | |
108 | ||
109 | static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) | |
110 | { | |
111 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
112 | ||
113 | subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); | |
114 | ||
115 | if (subflow->conn && !subflow->conn_finished) { | |
116 | pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk), | |
117 | subflow->remote_key); | |
118 | mptcp_finish_connect(sk); | |
119 | subflow->conn_finished = 1; | |
648ef4b8 MM |
120 | |
121 | if (skb) { | |
122 | pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq); | |
123 | subflow->ssn_offset = TCP_SKB_CB(skb)->seq; | |
124 | } | |
cec37a6e PK |
125 | } |
126 | } | |
127 | ||
128 | static struct request_sock_ops subflow_request_sock_ops; | |
129 | static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops; | |
130 | ||
131 | static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) | |
132 | { | |
133 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
134 | ||
135 | pr_debug("subflow=%p", subflow); | |
136 | ||
137 | /* Never answer to SYNs sent to broadcast or multicast */ | |
138 | if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) | |
139 | goto drop; | |
140 | ||
141 | return tcp_conn_request(&subflow_request_sock_ops, | |
142 | &subflow_request_sock_ipv4_ops, | |
143 | sk, skb); | |
144 | drop: | |
145 | tcp_listendrop(sk); | |
146 | return 0; | |
147 | } | |
148 | ||
149 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
150 | static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops; | |
151 | static struct inet_connection_sock_af_ops subflow_v6_specific; | |
152 | static struct inet_connection_sock_af_ops subflow_v6m_specific; | |
153 | ||
154 | static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) | |
155 | { | |
156 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
157 | ||
158 | pr_debug("subflow=%p", subflow); | |
159 | ||
160 | if (skb->protocol == htons(ETH_P_IP)) | |
161 | return subflow_v4_conn_request(sk, skb); | |
162 | ||
163 | if (!ipv6_unicast_destination(skb)) | |
164 | goto drop; | |
165 | ||
166 | return tcp_conn_request(&subflow_request_sock_ops, | |
167 | &subflow_request_sock_ipv6_ops, sk, skb); | |
168 | ||
169 | drop: | |
170 | tcp_listendrop(sk); | |
171 | return 0; /* don't send reset */ | |
172 | } | |
173 | #endif | |
174 | ||
175 | static struct sock *subflow_syn_recv_sock(const struct sock *sk, | |
176 | struct sk_buff *skb, | |
177 | struct request_sock *req, | |
178 | struct dst_entry *dst, | |
179 | struct request_sock *req_unhash, | |
180 | bool *own_req) | |
181 | { | |
182 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk); | |
cc7972ea CP |
183 | struct mptcp_subflow_request_sock *subflow_req; |
184 | struct tcp_options_received opt_rx; | |
58b09919 | 185 | struct sock *new_msk = NULL; |
cec37a6e PK |
186 | struct sock *child; |
187 | ||
188 | pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn); | |
189 | ||
ae2dd716 FW |
190 | if (tcp_rsk(req)->is_mptcp == 0) |
191 | goto create_child; | |
192 | ||
d22f4988 | 193 | /* if the sk is MP_CAPABLE, we try to fetch the client key */ |
cc7972ea CP |
194 | subflow_req = mptcp_subflow_rsk(req); |
195 | if (subflow_req->mp_capable) { | |
d22f4988 CP |
196 | if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) { |
197 | /* here we can receive and accept an in-window, | |
198 | * out-of-order pkt, which will not carry the MP_CAPABLE | |
199 | * opt even on mptcp enabled paths | |
200 | */ | |
58b09919 | 201 | goto create_msk; |
d22f4988 CP |
202 | } |
203 | ||
cc7972ea CP |
204 | opt_rx.mptcp.mp_capable = 0; |
205 | mptcp_get_options(skb, &opt_rx); | |
d22f4988 | 206 | if (opt_rx.mptcp.mp_capable) { |
cc7972ea | 207 | subflow_req->remote_key = opt_rx.mptcp.sndr_key; |
d22f4988 CP |
208 | subflow_req->remote_key_valid = 1; |
209 | } else { | |
210 | subflow_req->mp_capable = 0; | |
58b09919 | 211 | goto create_child; |
d22f4988 | 212 | } |
58b09919 PA |
213 | |
214 | create_msk: | |
215 | new_msk = mptcp_sk_clone(listener->conn, req); | |
216 | if (!new_msk) | |
217 | subflow_req->mp_capable = 0; | |
cc7972ea | 218 | } |
cec37a6e | 219 | |
d22f4988 | 220 | create_child: |
cec37a6e PK |
221 | child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, |
222 | req_unhash, own_req); | |
223 | ||
224 | if (child && *own_req) { | |
79c0949e PK |
225 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child); |
226 | ||
227 | /* we have null ctx on TCP fallback, not fatal on MPC | |
228 | * handshake | |
229 | */ | |
230 | if (!ctx) | |
58b09919 | 231 | goto out; |
79c0949e PK |
232 | |
233 | if (ctx->mp_capable) { | |
58b09919 PA |
234 | /* new mpc subflow takes ownership of the newly |
235 | * created mptcp socket | |
236 | */ | |
237 | ctx->conn = new_msk; | |
238 | new_msk = NULL; | |
cec37a6e PK |
239 | } |
240 | } | |
241 | ||
58b09919 PA |
242 | out: |
243 | /* dispose of the left over mptcp master, if any */ | |
244 | if (unlikely(new_msk)) | |
245 | sock_put(new_msk); | |
cec37a6e PK |
246 | return child; |
247 | } | |
248 | ||
249 | static struct inet_connection_sock_af_ops subflow_specific; | |
250 | ||
648ef4b8 MM |
251 | enum mapping_status { |
252 | MAPPING_OK, | |
253 | MAPPING_INVALID, | |
254 | MAPPING_EMPTY, | |
255 | MAPPING_DATA_FIN | |
256 | }; | |
257 | ||
258 | static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq) | |
259 | { | |
260 | if ((u32)seq == (u32)old_seq) | |
261 | return old_seq; | |
262 | ||
263 | /* Assume map covers data not mapped yet. */ | |
264 | return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32)); | |
265 | } | |
266 | ||
267 | static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) | |
268 | { | |
269 | WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d", | |
270 | ssn, subflow->map_subflow_seq, subflow->map_data_len); | |
271 | } | |
272 | ||
273 | static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) | |
274 | { | |
275 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
276 | unsigned int skb_consumed; | |
277 | ||
278 | skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; | |
279 | if (WARN_ON_ONCE(skb_consumed >= skb->len)) | |
280 | return true; | |
281 | ||
282 | return skb->len - skb_consumed <= subflow->map_data_len - | |
283 | mptcp_subflow_get_map_offset(subflow); | |
284 | } | |
285 | ||
286 | static bool validate_mapping(struct sock *ssk, struct sk_buff *skb) | |
287 | { | |
288 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
289 | u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; | |
290 | ||
291 | if (unlikely(before(ssn, subflow->map_subflow_seq))) { | |
292 | /* Mapping covers data later in the subflow stream, | |
293 | * currently unsupported. | |
294 | */ | |
295 | warn_bad_map(subflow, ssn); | |
296 | return false; | |
297 | } | |
298 | if (unlikely(!before(ssn, subflow->map_subflow_seq + | |
299 | subflow->map_data_len))) { | |
300 | /* Mapping does covers past subflow data, invalid */ | |
301 | warn_bad_map(subflow, ssn + skb->len); | |
302 | return false; | |
303 | } | |
304 | return true; | |
305 | } | |
306 | ||
307 | static enum mapping_status get_mapping_status(struct sock *ssk) | |
308 | { | |
309 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
310 | struct mptcp_ext *mpext; | |
311 | struct sk_buff *skb; | |
312 | u16 data_len; | |
313 | u64 map_seq; | |
314 | ||
315 | skb = skb_peek(&ssk->sk_receive_queue); | |
316 | if (!skb) | |
317 | return MAPPING_EMPTY; | |
318 | ||
319 | mpext = mptcp_get_ext(skb); | |
320 | if (!mpext || !mpext->use_map) { | |
321 | if (!subflow->map_valid && !skb->len) { | |
322 | /* the TCP stack deliver 0 len FIN pkt to the receive | |
323 | * queue, that is the only 0len pkts ever expected here, | |
324 | * and we can admit no mapping only for 0 len pkts | |
325 | */ | |
326 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) | |
327 | WARN_ONCE(1, "0len seq %d:%d flags %x", | |
328 | TCP_SKB_CB(skb)->seq, | |
329 | TCP_SKB_CB(skb)->end_seq, | |
330 | TCP_SKB_CB(skb)->tcp_flags); | |
331 | sk_eat_skb(ssk, skb); | |
332 | return MAPPING_EMPTY; | |
333 | } | |
334 | ||
335 | if (!subflow->map_valid) | |
336 | return MAPPING_INVALID; | |
337 | ||
338 | goto validate_seq; | |
339 | } | |
340 | ||
341 | pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d", | |
342 | mpext->data_seq, mpext->dsn64, mpext->subflow_seq, | |
343 | mpext->data_len, mpext->data_fin); | |
344 | ||
345 | data_len = mpext->data_len; | |
346 | if (data_len == 0) { | |
347 | pr_err("Infinite mapping not handled"); | |
348 | return MAPPING_INVALID; | |
349 | } | |
350 | ||
351 | if (mpext->data_fin == 1) { | |
352 | if (data_len == 1) { | |
353 | pr_debug("DATA_FIN with no payload"); | |
354 | if (subflow->map_valid) { | |
355 | /* A DATA_FIN might arrive in a DSS | |
356 | * option before the previous mapping | |
357 | * has been fully consumed. Continue | |
358 | * handling the existing mapping. | |
359 | */ | |
360 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
361 | return MAPPING_OK; | |
362 | } else { | |
363 | return MAPPING_DATA_FIN; | |
364 | } | |
365 | } | |
366 | ||
367 | /* Adjust for DATA_FIN using 1 byte of sequence space */ | |
368 | data_len--; | |
369 | } | |
370 | ||
371 | if (!mpext->dsn64) { | |
372 | map_seq = expand_seq(subflow->map_seq, subflow->map_data_len, | |
373 | mpext->data_seq); | |
374 | pr_debug("expanded seq=%llu", subflow->map_seq); | |
375 | } else { | |
376 | map_seq = mpext->data_seq; | |
377 | } | |
378 | ||
379 | if (subflow->map_valid) { | |
380 | /* Allow replacing only with an identical map */ | |
381 | if (subflow->map_seq == map_seq && | |
382 | subflow->map_subflow_seq == mpext->subflow_seq && | |
383 | subflow->map_data_len == data_len) { | |
384 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
385 | return MAPPING_OK; | |
386 | } | |
387 | ||
388 | /* If this skb data are fully covered by the current mapping, | |
389 | * the new map would need caching, which is not supported | |
390 | */ | |
391 | if (skb_is_fully_mapped(ssk, skb)) | |
392 | return MAPPING_INVALID; | |
393 | ||
394 | /* will validate the next map after consuming the current one */ | |
395 | return MAPPING_OK; | |
396 | } | |
397 | ||
398 | subflow->map_seq = map_seq; | |
399 | subflow->map_subflow_seq = mpext->subflow_seq; | |
400 | subflow->map_data_len = data_len; | |
401 | subflow->map_valid = 1; | |
d22f4988 | 402 | subflow->mpc_map = mpext->mpc_map; |
648ef4b8 MM |
403 | pr_debug("new map seq=%llu subflow_seq=%u data_len=%u", |
404 | subflow->map_seq, subflow->map_subflow_seq, | |
405 | subflow->map_data_len); | |
406 | ||
407 | validate_seq: | |
408 | /* we revalidate valid mapping on new skb, because we must ensure | |
409 | * the current skb is completely covered by the available mapping | |
410 | */ | |
411 | if (!validate_mapping(ssk, skb)) | |
412 | return MAPPING_INVALID; | |
413 | ||
414 | skb_ext_del(skb, SKB_EXT_MPTCP); | |
415 | return MAPPING_OK; | |
416 | } | |
417 | ||
bfae9dae FW |
418 | static int subflow_read_actor(read_descriptor_t *desc, |
419 | struct sk_buff *skb, | |
420 | unsigned int offset, size_t len) | |
421 | { | |
422 | size_t copy_len = min(desc->count, len); | |
423 | ||
424 | desc->count -= copy_len; | |
425 | ||
426 | pr_debug("flushed %zu bytes, %zu left", copy_len, desc->count); | |
427 | return copy_len; | |
428 | } | |
429 | ||
648ef4b8 MM |
430 | static bool subflow_check_data_avail(struct sock *ssk) |
431 | { | |
432 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); | |
433 | enum mapping_status status; | |
434 | struct mptcp_sock *msk; | |
435 | struct sk_buff *skb; | |
436 | ||
437 | pr_debug("msk=%p ssk=%p data_avail=%d skb=%p", subflow->conn, ssk, | |
438 | subflow->data_avail, skb_peek(&ssk->sk_receive_queue)); | |
439 | if (subflow->data_avail) | |
440 | return true; | |
441 | ||
442 | if (!subflow->conn) | |
443 | return false; | |
444 | ||
445 | msk = mptcp_sk(subflow->conn); | |
446 | for (;;) { | |
447 | u32 map_remaining; | |
448 | size_t delta; | |
449 | u64 ack_seq; | |
450 | u64 old_ack; | |
451 | ||
452 | status = get_mapping_status(ssk); | |
453 | pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status); | |
454 | if (status == MAPPING_INVALID) { | |
455 | ssk->sk_err = EBADMSG; | |
456 | goto fatal; | |
457 | } | |
458 | ||
459 | if (status != MAPPING_OK) | |
460 | return false; | |
461 | ||
462 | skb = skb_peek(&ssk->sk_receive_queue); | |
463 | if (WARN_ON_ONCE(!skb)) | |
464 | return false; | |
465 | ||
d22f4988 CP |
466 | /* if msk lacks the remote key, this subflow must provide an |
467 | * MP_CAPABLE-based mapping | |
468 | */ | |
469 | if (unlikely(!READ_ONCE(msk->can_ack))) { | |
470 | if (!subflow->mpc_map) { | |
471 | ssk->sk_err = EBADMSG; | |
472 | goto fatal; | |
473 | } | |
474 | WRITE_ONCE(msk->remote_key, subflow->remote_key); | |
475 | WRITE_ONCE(msk->ack_seq, subflow->map_seq); | |
476 | WRITE_ONCE(msk->can_ack, true); | |
477 | } | |
478 | ||
648ef4b8 MM |
479 | old_ack = READ_ONCE(msk->ack_seq); |
480 | ack_seq = mptcp_subflow_get_mapped_dsn(subflow); | |
481 | pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack, | |
482 | ack_seq); | |
483 | if (ack_seq == old_ack) | |
484 | break; | |
485 | ||
486 | /* only accept in-sequence mapping. Old values are spurious | |
487 | * retransmission; we can hit "future" values on active backup | |
488 | * subflow switch, we relay on retransmissions to get | |
489 | * in-sequence data. | |
490 | * Cuncurrent subflows support will require subflow data | |
491 | * reordering | |
492 | */ | |
493 | map_remaining = subflow->map_data_len - | |
494 | mptcp_subflow_get_map_offset(subflow); | |
495 | if (before64(ack_seq, old_ack)) | |
496 | delta = min_t(size_t, old_ack - ack_seq, map_remaining); | |
497 | else | |
498 | delta = min_t(size_t, ack_seq - old_ack, map_remaining); | |
499 | ||
500 | /* discard mapped data */ | |
501 | pr_debug("discarding %zu bytes, current map len=%d", delta, | |
502 | map_remaining); | |
503 | if (delta) { | |
648ef4b8 MM |
504 | read_descriptor_t desc = { |
505 | .count = delta, | |
648ef4b8 MM |
506 | }; |
507 | int ret; | |
508 | ||
bfae9dae | 509 | ret = tcp_read_sock(ssk, &desc, subflow_read_actor); |
648ef4b8 MM |
510 | if (ret < 0) { |
511 | ssk->sk_err = -ret; | |
512 | goto fatal; | |
513 | } | |
514 | if (ret < delta) | |
515 | return false; | |
516 | if (delta == map_remaining) | |
517 | subflow->map_valid = 0; | |
518 | } | |
519 | } | |
520 | return true; | |
521 | ||
522 | fatal: | |
523 | /* fatal protocol error, close the socket */ | |
524 | /* This barrier is coupled with smp_rmb() in tcp_poll() */ | |
525 | smp_wmb(); | |
526 | ssk->sk_error_report(ssk); | |
527 | tcp_set_state(ssk, TCP_CLOSE); | |
528 | tcp_send_active_reset(ssk, GFP_ATOMIC); | |
529 | return false; | |
530 | } | |
531 | ||
532 | bool mptcp_subflow_data_available(struct sock *sk) | |
533 | { | |
534 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
535 | struct sk_buff *skb; | |
536 | ||
537 | /* check if current mapping is still valid */ | |
538 | if (subflow->map_valid && | |
539 | mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) { | |
540 | subflow->map_valid = 0; | |
541 | subflow->data_avail = 0; | |
542 | ||
543 | pr_debug("Done with mapping: seq=%u data_len=%u", | |
544 | subflow->map_subflow_seq, | |
545 | subflow->map_data_len); | |
546 | } | |
547 | ||
548 | if (!subflow_check_data_avail(sk)) { | |
549 | subflow->data_avail = 0; | |
550 | return false; | |
551 | } | |
552 | ||
553 | skb = skb_peek(&sk->sk_receive_queue); | |
554 | subflow->data_avail = skb && | |
555 | before(tcp_sk(sk)->copied_seq, TCP_SKB_CB(skb)->end_seq); | |
556 | return subflow->data_avail; | |
557 | } | |
558 | ||
559 | static void subflow_data_ready(struct sock *sk) | |
560 | { | |
561 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
562 | struct sock *parent = subflow->conn; | |
563 | ||
564 | if (!parent || !subflow->mp_capable) { | |
565 | subflow->tcp_data_ready(sk); | |
566 | ||
567 | if (parent) | |
568 | parent->sk_data_ready(parent); | |
569 | return; | |
570 | } | |
571 | ||
101f6f85 | 572 | if (mptcp_subflow_data_available(sk)) |
2e52213c | 573 | mptcp_data_ready(parent, sk); |
648ef4b8 MM |
574 | } |
575 | ||
576 | static void subflow_write_space(struct sock *sk) | |
577 | { | |
578 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
579 | struct sock *parent = subflow->conn; | |
580 | ||
581 | sk_stream_write_space(sk); | |
582 | if (parent && sk_stream_is_writeable(sk)) { | |
1891c4a0 FW |
583 | set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags); |
584 | smp_mb__after_atomic(); | |
585 | /* set SEND_SPACE before sk_stream_write_space clears NOSPACE */ | |
648ef4b8 MM |
586 | sk_stream_write_space(parent); |
587 | } | |
588 | } | |
589 | ||
cec37a6e PK |
590 | static struct inet_connection_sock_af_ops * |
591 | subflow_default_af_ops(struct sock *sk) | |
592 | { | |
593 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
594 | if (sk->sk_family == AF_INET6) | |
595 | return &subflow_v6_specific; | |
596 | #endif | |
597 | return &subflow_specific; | |
598 | } | |
599 | ||
cec37a6e | 600 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
31484d56 GU |
601 | void mptcpv6_handle_mapped(struct sock *sk, bool mapped) |
602 | { | |
cec37a6e PK |
603 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
604 | struct inet_connection_sock *icsk = inet_csk(sk); | |
605 | struct inet_connection_sock_af_ops *target; | |
606 | ||
607 | target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk); | |
608 | ||
609 | pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d", | |
edc7e489 | 610 | subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped); |
cec37a6e PK |
611 | |
612 | if (likely(icsk->icsk_af_ops == target)) | |
613 | return; | |
614 | ||
615 | subflow->icsk_af_ops = icsk->icsk_af_ops; | |
616 | icsk->icsk_af_ops = target; | |
cec37a6e | 617 | } |
31484d56 | 618 | #endif |
cec37a6e | 619 | |
2303f994 PK |
620 | int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock) |
621 | { | |
622 | struct mptcp_subflow_context *subflow; | |
623 | struct net *net = sock_net(sk); | |
624 | struct socket *sf; | |
625 | int err; | |
626 | ||
cec37a6e PK |
627 | err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP, |
628 | &sf); | |
2303f994 PK |
629 | if (err) |
630 | return err; | |
631 | ||
632 | lock_sock(sf->sk); | |
633 | ||
634 | /* kernel sockets do not by default acquire net ref, but TCP timer | |
635 | * needs it. | |
636 | */ | |
637 | sf->sk->sk_net_refcnt = 1; | |
638 | get_net(net); | |
f6f7d8cf | 639 | #ifdef CONFIG_PROC_FS |
2303f994 | 640 | this_cpu_add(*net->core.sock_inuse, 1); |
f6f7d8cf | 641 | #endif |
2303f994 PK |
642 | err = tcp_set_ulp(sf->sk, "mptcp"); |
643 | release_sock(sf->sk); | |
644 | ||
645 | if (err) | |
646 | return err; | |
647 | ||
648 | subflow = mptcp_subflow_ctx(sf->sk); | |
649 | pr_debug("subflow=%p", subflow); | |
650 | ||
651 | *new_sock = sf; | |
79c0949e | 652 | sock_hold(sk); |
2303f994 PK |
653 | subflow->conn = sk; |
654 | ||
655 | return 0; | |
656 | } | |
657 | ||
658 | static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk, | |
659 | gfp_t priority) | |
660 | { | |
661 | struct inet_connection_sock *icsk = inet_csk(sk); | |
662 | struct mptcp_subflow_context *ctx; | |
663 | ||
664 | ctx = kzalloc(sizeof(*ctx), priority); | |
665 | if (!ctx) | |
666 | return NULL; | |
667 | ||
668 | rcu_assign_pointer(icsk->icsk_ulp_data, ctx); | |
cec37a6e | 669 | INIT_LIST_HEAD(&ctx->node); |
2303f994 PK |
670 | |
671 | pr_debug("subflow=%p", ctx); | |
672 | ||
673 | ctx->tcp_sock = sk; | |
674 | ||
675 | return ctx; | |
676 | } | |
677 | ||
648ef4b8 MM |
678 | static void __subflow_state_change(struct sock *sk) |
679 | { | |
680 | struct socket_wq *wq; | |
681 | ||
682 | rcu_read_lock(); | |
683 | wq = rcu_dereference(sk->sk_wq); | |
684 | if (skwq_has_sleeper(wq)) | |
685 | wake_up_interruptible_all(&wq->wait); | |
686 | rcu_read_unlock(); | |
687 | } | |
688 | ||
689 | static bool subflow_is_done(const struct sock *sk) | |
690 | { | |
691 | return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE; | |
692 | } | |
693 | ||
694 | static void subflow_state_change(struct sock *sk) | |
695 | { | |
696 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
697 | struct sock *parent = READ_ONCE(subflow->conn); | |
698 | ||
699 | __subflow_state_change(sk); | |
700 | ||
701 | /* as recvmsg() does not acquire the subflow socket for ssk selection | |
702 | * a fin packet carrying a DSS can be unnoticed if we don't trigger | |
703 | * the data available machinery here. | |
704 | */ | |
101f6f85 | 705 | if (parent && subflow->mp_capable && mptcp_subflow_data_available(sk)) |
2e52213c | 706 | mptcp_data_ready(parent, sk); |
648ef4b8 MM |
707 | |
708 | if (parent && !(parent->sk_shutdown & RCV_SHUTDOWN) && | |
709 | !subflow->rx_eof && subflow_is_done(sk)) { | |
710 | subflow->rx_eof = 1; | |
711 | parent->sk_shutdown |= RCV_SHUTDOWN; | |
712 | __subflow_state_change(parent); | |
713 | } | |
714 | } | |
715 | ||
2303f994 PK |
716 | static int subflow_ulp_init(struct sock *sk) |
717 | { | |
cec37a6e | 718 | struct inet_connection_sock *icsk = inet_csk(sk); |
2303f994 PK |
719 | struct mptcp_subflow_context *ctx; |
720 | struct tcp_sock *tp = tcp_sk(sk); | |
721 | int err = 0; | |
722 | ||
723 | /* disallow attaching ULP to a socket unless it has been | |
724 | * created with sock_create_kern() | |
725 | */ | |
726 | if (!sk->sk_kern_sock) { | |
727 | err = -EOPNOTSUPP; | |
728 | goto out; | |
729 | } | |
730 | ||
731 | ctx = subflow_create_ctx(sk, GFP_KERNEL); | |
732 | if (!ctx) { | |
733 | err = -ENOMEM; | |
734 | goto out; | |
735 | } | |
736 | ||
737 | pr_debug("subflow=%p, family=%d", ctx, sk->sk_family); | |
738 | ||
739 | tp->is_mptcp = 1; | |
cec37a6e PK |
740 | ctx->icsk_af_ops = icsk->icsk_af_ops; |
741 | icsk->icsk_af_ops = subflow_default_af_ops(sk); | |
648ef4b8 MM |
742 | ctx->tcp_data_ready = sk->sk_data_ready; |
743 | ctx->tcp_state_change = sk->sk_state_change; | |
744 | ctx->tcp_write_space = sk->sk_write_space; | |
745 | sk->sk_data_ready = subflow_data_ready; | |
746 | sk->sk_write_space = subflow_write_space; | |
747 | sk->sk_state_change = subflow_state_change; | |
2303f994 PK |
748 | out: |
749 | return err; | |
750 | } | |
751 | ||
752 | static void subflow_ulp_release(struct sock *sk) | |
753 | { | |
754 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk); | |
755 | ||
756 | if (!ctx) | |
757 | return; | |
758 | ||
79c0949e PK |
759 | if (ctx->conn) |
760 | sock_put(ctx->conn); | |
761 | ||
2303f994 PK |
762 | kfree_rcu(ctx, rcu); |
763 | } | |
764 | ||
648ef4b8 MM |
765 | static void subflow_ulp_fallback(struct sock *sk, |
766 | struct mptcp_subflow_context *old_ctx) | |
cec37a6e PK |
767 | { |
768 | struct inet_connection_sock *icsk = inet_csk(sk); | |
769 | ||
648ef4b8 | 770 | mptcp_subflow_tcp_fallback(sk, old_ctx); |
cec37a6e PK |
771 | icsk->icsk_ulp_ops = NULL; |
772 | rcu_assign_pointer(icsk->icsk_ulp_data, NULL); | |
773 | tcp_sk(sk)->is_mptcp = 0; | |
774 | } | |
775 | ||
776 | static void subflow_ulp_clone(const struct request_sock *req, | |
777 | struct sock *newsk, | |
778 | const gfp_t priority) | |
779 | { | |
780 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
781 | struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk); | |
782 | struct mptcp_subflow_context *new_ctx; | |
783 | ||
ae2dd716 | 784 | if (!tcp_rsk(req)->is_mptcp || !subflow_req->mp_capable) { |
648ef4b8 | 785 | subflow_ulp_fallback(newsk, old_ctx); |
cec37a6e PK |
786 | return; |
787 | } | |
788 | ||
789 | new_ctx = subflow_create_ctx(newsk, priority); | |
edc7e489 | 790 | if (!new_ctx) { |
648ef4b8 | 791 | subflow_ulp_fallback(newsk, old_ctx); |
cec37a6e PK |
792 | return; |
793 | } | |
794 | ||
d22f4988 CP |
795 | /* see comments in subflow_syn_recv_sock(), MPTCP connection is fully |
796 | * established only after we receive the remote key | |
797 | */ | |
cec37a6e PK |
798 | new_ctx->conn_finished = 1; |
799 | new_ctx->icsk_af_ops = old_ctx->icsk_af_ops; | |
648ef4b8 MM |
800 | new_ctx->tcp_data_ready = old_ctx->tcp_data_ready; |
801 | new_ctx->tcp_state_change = old_ctx->tcp_state_change; | |
802 | new_ctx->tcp_write_space = old_ctx->tcp_write_space; | |
58b09919 PA |
803 | new_ctx->rel_write_seq = 1; |
804 | new_ctx->tcp_sock = newsk; | |
805 | ||
cec37a6e | 806 | new_ctx->mp_capable = 1; |
d22f4988 CP |
807 | new_ctx->fourth_ack = subflow_req->remote_key_valid; |
808 | new_ctx->can_ack = subflow_req->remote_key_valid; | |
cec37a6e PK |
809 | new_ctx->remote_key = subflow_req->remote_key; |
810 | new_ctx->local_key = subflow_req->local_key; | |
79c0949e | 811 | new_ctx->token = subflow_req->token; |
648ef4b8 MM |
812 | new_ctx->ssn_offset = subflow_req->ssn_offset; |
813 | new_ctx->idsn = subflow_req->idsn; | |
cec37a6e PK |
814 | } |
815 | ||
2303f994 PK |
816 | static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { |
817 | .name = "mptcp", | |
818 | .owner = THIS_MODULE, | |
819 | .init = subflow_ulp_init, | |
820 | .release = subflow_ulp_release, | |
cec37a6e | 821 | .clone = subflow_ulp_clone, |
2303f994 PK |
822 | }; |
823 | ||
cec37a6e PK |
824 | static int subflow_ops_init(struct request_sock_ops *subflow_ops) |
825 | { | |
826 | subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock); | |
827 | subflow_ops->slab_name = "request_sock_subflow"; | |
828 | ||
829 | subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name, | |
830 | subflow_ops->obj_size, 0, | |
831 | SLAB_ACCOUNT | | |
832 | SLAB_TYPESAFE_BY_RCU, | |
833 | NULL); | |
834 | if (!subflow_ops->slab) | |
835 | return -ENOMEM; | |
836 | ||
79c0949e PK |
837 | subflow_ops->destructor = subflow_req_destructor; |
838 | ||
cec37a6e PK |
839 | return 0; |
840 | } | |
841 | ||
2303f994 PK |
842 | void mptcp_subflow_init(void) |
843 | { | |
cec37a6e PK |
844 | subflow_request_sock_ops = tcp_request_sock_ops; |
845 | if (subflow_ops_init(&subflow_request_sock_ops) != 0) | |
846 | panic("MPTCP: failed to init subflow request sock ops\n"); | |
847 | ||
848 | subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops; | |
849 | subflow_request_sock_ipv4_ops.init_req = subflow_v4_init_req; | |
850 | ||
851 | subflow_specific = ipv4_specific; | |
852 | subflow_specific.conn_request = subflow_v4_conn_request; | |
853 | subflow_specific.syn_recv_sock = subflow_syn_recv_sock; | |
854 | subflow_specific.sk_rx_dst_set = subflow_finish_connect; | |
79c0949e | 855 | subflow_specific.rebuild_header = subflow_rebuild_header; |
cec37a6e PK |
856 | |
857 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
858 | subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; | |
859 | subflow_request_sock_ipv6_ops.init_req = subflow_v6_init_req; | |
860 | ||
861 | subflow_v6_specific = ipv6_specific; | |
862 | subflow_v6_specific.conn_request = subflow_v6_conn_request; | |
863 | subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; | |
864 | subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; | |
79c0949e | 865 | subflow_v6_specific.rebuild_header = subflow_rebuild_header; |
cec37a6e PK |
866 | |
867 | subflow_v6m_specific = subflow_v6_specific; | |
868 | subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; | |
869 | subflow_v6m_specific.send_check = ipv4_specific.send_check; | |
870 | subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; | |
871 | subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; | |
872 | subflow_v6m_specific.net_frag_header_len = 0; | |
873 | #endif | |
874 | ||
2303f994 PK |
875 | if (tcp_register_ulp(&subflow_ulp_ops) != 0) |
876 | panic("MPTCP: failed to register subflows to ULP\n"); | |
877 | } |