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eda7acdd PK |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Multipath TCP | |
3 | * | |
4 | * Copyright (c) 2017 - 2019, Intel Corporation. | |
5 | */ | |
6 | ||
c85adced GT |
7 | #define pr_fmt(fmt) "MPTCP: " fmt |
8 | ||
eda7acdd | 9 | #include <linux/kernel.h> |
a24d22b2 | 10 | #include <crypto/sha2.h> |
eda7acdd PK |
11 | #include <net/tcp.h> |
12 | #include <net/mptcp.h> | |
13 | #include "protocol.h" | |
a877de06 | 14 | #include "mib.h" |
eda7acdd | 15 | |
65492c5a PA |
16 | static bool mptcp_cap_flag_sha256(u8 flags) |
17 | { | |
18 | return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; | |
19 | } | |
20 | ||
cfde141e PA |
21 | static void mptcp_parse_option(const struct sk_buff *skb, |
22 | const unsigned char *ptr, int opsize, | |
23 | struct mptcp_options_received *mp_opt) | |
eda7acdd | 24 | { |
eda7acdd | 25 | u8 subtype = *ptr >> 4; |
648ef4b8 | 26 | int expected_opsize; |
eda7acdd PK |
27 | u8 version; |
28 | u8 flags; | |
5c4a824d | 29 | u8 i; |
eda7acdd PK |
30 | |
31 | switch (subtype) { | |
32 | case MPTCPOPT_MP_CAPABLE: | |
cc7972ea CP |
33 | /* strict size checking */ |
34 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { | |
35 | if (skb->len > tcp_hdr(skb)->doff << 2) | |
36 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
37 | else | |
38 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK; | |
39 | } else { | |
40 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) | |
41 | expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; | |
42 | else | |
43 | expected_opsize = TCPOLEN_MPTCP_MPC_SYN; | |
44 | } | |
45 | if (opsize != expected_opsize) | |
eda7acdd PK |
46 | break; |
47 | ||
cc7972ea | 48 | /* try to be gentle vs future versions on the initial syn */ |
eda7acdd | 49 | version = *ptr++ & MPTCP_VERSION_MASK; |
cc7972ea CP |
50 | if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
51 | if (version != MPTCP_SUPPORTED_VERSION) | |
52 | break; | |
53 | } else if (version < MPTCP_SUPPORTED_VERSION) { | |
eda7acdd | 54 | break; |
cc7972ea | 55 | } |
eda7acdd PK |
56 | |
57 | flags = *ptr++; | |
65492c5a | 58 | if (!mptcp_cap_flag_sha256(flags) || |
eda7acdd PK |
59 | (flags & MPTCP_CAP_EXTENSIBILITY)) |
60 | break; | |
61 | ||
62 | /* RFC 6824, Section 3.1: | |
63 | * "For the Checksum Required bit (labeled "A"), if either | |
64 | * host requires the use of checksums, checksums MUST be used. | |
65 | * In other words, the only way for checksums not to be used | |
66 | * is if both hosts in their SYNs set A=0." | |
67 | * | |
68 | * Section 3.3.0: | |
69 | * "If a checksum is not present when its use has been | |
70 | * negotiated, the receiver MUST close the subflow with a RST as | |
71 | * it is considered broken." | |
72 | * | |
73 | * We don't implement DSS checksum - fall back to TCP. | |
74 | */ | |
75 | if (flags & MPTCP_CAP_CHECKSUM_REQD) | |
76 | break; | |
77 | ||
78 | mp_opt->mp_capable = 1; | |
cc7972ea CP |
79 | if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
80 | mp_opt->sndr_key = get_unaligned_be64(ptr); | |
81 | ptr += 8; | |
82 | } | |
83 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { | |
eda7acdd PK |
84 | mp_opt->rcvr_key = get_unaligned_be64(ptr); |
85 | ptr += 8; | |
eda7acdd | 86 | } |
cc7972ea CP |
87 | if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) { |
88 | /* Section 3.1.: | |
89 | * "the data parameters in a MP_CAPABLE are semantically | |
90 | * equivalent to those in a DSS option and can be used | |
91 | * interchangeably." | |
92 | */ | |
93 | mp_opt->dss = 1; | |
94 | mp_opt->use_map = 1; | |
95 | mp_opt->mpc_map = 1; | |
96 | mp_opt->data_len = get_unaligned_be16(ptr); | |
97 | ptr += 2; | |
98 | } | |
99 | pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d", | |
100 | version, flags, opsize, mp_opt->sndr_key, | |
101 | mp_opt->rcvr_key, mp_opt->data_len); | |
eda7acdd PK |
102 | break; |
103 | ||
f296234c PK |
104 | case MPTCPOPT_MP_JOIN: |
105 | mp_opt->mp_join = 1; | |
106 | if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { | |
107 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; | |
108 | mp_opt->join_id = *ptr++; | |
109 | mp_opt->token = get_unaligned_be32(ptr); | |
110 | ptr += 4; | |
111 | mp_opt->nonce = get_unaligned_be32(ptr); | |
112 | ptr += 4; | |
113 | pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", | |
114 | mp_opt->backup, mp_opt->join_id, | |
115 | mp_opt->token, mp_opt->nonce); | |
116 | } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { | |
117 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; | |
118 | mp_opt->join_id = *ptr++; | |
119 | mp_opt->thmac = get_unaligned_be64(ptr); | |
120 | ptr += 8; | |
121 | mp_opt->nonce = get_unaligned_be32(ptr); | |
122 | ptr += 4; | |
123 | pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", | |
124 | mp_opt->backup, mp_opt->join_id, | |
125 | mp_opt->thmac, mp_opt->nonce); | |
126 | } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { | |
127 | ptr += 2; | |
128 | memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); | |
129 | pr_debug("MP_JOIN hmac"); | |
130 | } else { | |
131 | pr_warn("MP_JOIN bad option size"); | |
132 | mp_opt->mp_join = 0; | |
133 | } | |
134 | break; | |
135 | ||
eda7acdd PK |
136 | case MPTCPOPT_DSS: |
137 | pr_debug("DSS"); | |
648ef4b8 MM |
138 | ptr++; |
139 | ||
cc7972ea CP |
140 | /* we must clear 'mpc_map' be able to detect MP_CAPABLE |
141 | * map vs DSS map in mptcp_incoming_options(), and reconstruct | |
142 | * map info accordingly | |
143 | */ | |
144 | mp_opt->mpc_map = 0; | |
648ef4b8 MM |
145 | flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
146 | mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; | |
147 | mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; | |
148 | mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; | |
149 | mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; | |
150 | mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); | |
151 | ||
152 | pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", | |
153 | mp_opt->data_fin, mp_opt->dsn64, | |
154 | mp_opt->use_map, mp_opt->ack64, | |
155 | mp_opt->use_ack); | |
156 | ||
157 | expected_opsize = TCPOLEN_MPTCP_DSS_BASE; | |
158 | ||
159 | if (mp_opt->use_ack) { | |
160 | if (mp_opt->ack64) | |
161 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; | |
162 | else | |
163 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; | |
164 | } | |
165 | ||
166 | if (mp_opt->use_map) { | |
167 | if (mp_opt->dsn64) | |
168 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; | |
169 | else | |
170 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; | |
171 | } | |
172 | ||
173 | /* RFC 6824, Section 3.3: | |
174 | * If a checksum is present, but its use had | |
175 | * not been negotiated in the MP_CAPABLE handshake, | |
176 | * the checksum field MUST be ignored. | |
177 | */ | |
178 | if (opsize != expected_opsize && | |
179 | opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) | |
180 | break; | |
181 | ||
eda7acdd | 182 | mp_opt->dss = 1; |
648ef4b8 MM |
183 | |
184 | if (mp_opt->use_ack) { | |
185 | if (mp_opt->ack64) { | |
186 | mp_opt->data_ack = get_unaligned_be64(ptr); | |
187 | ptr += 8; | |
188 | } else { | |
189 | mp_opt->data_ack = get_unaligned_be32(ptr); | |
190 | ptr += 4; | |
191 | } | |
192 | ||
193 | pr_debug("data_ack=%llu", mp_opt->data_ack); | |
194 | } | |
195 | ||
196 | if (mp_opt->use_map) { | |
197 | if (mp_opt->dsn64) { | |
198 | mp_opt->data_seq = get_unaligned_be64(ptr); | |
199 | ptr += 8; | |
200 | } else { | |
201 | mp_opt->data_seq = get_unaligned_be32(ptr); | |
202 | ptr += 4; | |
203 | } | |
204 | ||
205 | mp_opt->subflow_seq = get_unaligned_be32(ptr); | |
206 | ptr += 4; | |
207 | ||
208 | mp_opt->data_len = get_unaligned_be16(ptr); | |
209 | ptr += 2; | |
210 | ||
211 | pr_debug("data_seq=%llu subflow_seq=%u data_len=%u", | |
212 | mp_opt->data_seq, mp_opt->subflow_seq, | |
213 | mp_opt->data_len); | |
214 | } | |
215 | ||
eda7acdd PK |
216 | break; |
217 | ||
3df523ab PK |
218 | case MPTCPOPT_ADD_ADDR: |
219 | mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; | |
220 | if (!mp_opt->echo) { | |
221 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR || | |
222 | opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) | |
223 | mp_opt->family = MPTCP_ADDR_IPVERSION_4; | |
224 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
225 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || | |
226 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) | |
227 | mp_opt->family = MPTCP_ADDR_IPVERSION_6; | |
228 | #endif | |
229 | else | |
230 | break; | |
231 | } else { | |
232 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || | |
233 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) | |
234 | mp_opt->family = MPTCP_ADDR_IPVERSION_4; | |
235 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
236 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || | |
237 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) | |
238 | mp_opt->family = MPTCP_ADDR_IPVERSION_6; | |
239 | #endif | |
240 | else | |
241 | break; | |
242 | } | |
243 | ||
244 | mp_opt->add_addr = 1; | |
3df523ab | 245 | mp_opt->addr_id = *ptr++; |
3df523ab PK |
246 | if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) { |
247 | memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4); | |
248 | ptr += 4; | |
249 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || | |
250 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { | |
251 | mp_opt->port = get_unaligned_be16(ptr); | |
252 | ptr += 2; | |
253 | } | |
254 | } | |
255 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
256 | else { | |
257 | memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16); | |
258 | ptr += 16; | |
259 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || | |
260 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { | |
261 | mp_opt->port = get_unaligned_be16(ptr); | |
262 | ptr += 2; | |
263 | } | |
264 | } | |
265 | #endif | |
266 | if (!mp_opt->echo) { | |
267 | mp_opt->ahmac = get_unaligned_be64(ptr); | |
268 | ptr += 8; | |
269 | } | |
90a4aea8 GT |
270 | pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", |
271 | (mp_opt->family == MPTCP_ADDR_IPVERSION_6) ? "6" : "", | |
272 | mp_opt->addr_id, mp_opt->ahmac, mp_opt->echo, mp_opt->port); | |
3df523ab PK |
273 | break; |
274 | ||
275 | case MPTCPOPT_RM_ADDR: | |
5c4a824d GT |
276 | if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || |
277 | opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) | |
3df523ab PK |
278 | break; |
279 | ||
8e60eed6 GT |
280 | ptr++; |
281 | ||
3df523ab | 282 | mp_opt->rm_addr = 1; |
5c4a824d GT |
283 | mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; |
284 | for (i = 0; i < mp_opt->rm_list.nr; i++) | |
285 | mp_opt->rm_list.ids[i] = *ptr++; | |
286 | pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr); | |
3df523ab PK |
287 | break; |
288 | ||
40453a5c GT |
289 | case MPTCPOPT_MP_PRIO: |
290 | if (opsize != TCPOLEN_MPTCP_PRIO) | |
291 | break; | |
292 | ||
293 | mp_opt->mp_prio = 1; | |
294 | mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; | |
295 | pr_debug("MP_PRIO: prio=%d", mp_opt->backup); | |
296 | break; | |
297 | ||
50c504a2 FW |
298 | case MPTCPOPT_MP_FASTCLOSE: |
299 | if (opsize != TCPOLEN_MPTCP_FASTCLOSE) | |
300 | break; | |
301 | ||
302 | ptr += 2; | |
303 | mp_opt->rcvr_key = get_unaligned_be64(ptr); | |
304 | ptr += 8; | |
305 | mp_opt->fastclose = 1; | |
306 | break; | |
307 | ||
eda7acdd PK |
308 | default: |
309 | break; | |
310 | } | |
311 | } | |
312 | ||
cec37a6e | 313 | void mptcp_get_options(const struct sk_buff *skb, |
cfde141e | 314 | struct mptcp_options_received *mp_opt) |
cec37a6e | 315 | { |
cec37a6e | 316 | const struct tcphdr *th = tcp_hdr(skb); |
cfde141e PA |
317 | const unsigned char *ptr; |
318 | int length; | |
cec37a6e | 319 | |
cfde141e PA |
320 | /* initialize option status */ |
321 | mp_opt->mp_capable = 0; | |
322 | mp_opt->mp_join = 0; | |
323 | mp_opt->add_addr = 0; | |
fe2d9b1a | 324 | mp_opt->ahmac = 0; |
50c504a2 | 325 | mp_opt->fastclose = 0; |
65b8c8a6 | 326 | mp_opt->port = 0; |
cfde141e PA |
327 | mp_opt->rm_addr = 0; |
328 | mp_opt->dss = 0; | |
40453a5c | 329 | mp_opt->mp_prio = 0; |
cfde141e PA |
330 | |
331 | length = (th->doff * 4) - sizeof(struct tcphdr); | |
cec37a6e PK |
332 | ptr = (const unsigned char *)(th + 1); |
333 | ||
334 | while (length > 0) { | |
335 | int opcode = *ptr++; | |
336 | int opsize; | |
337 | ||
338 | switch (opcode) { | |
339 | case TCPOPT_EOL: | |
340 | return; | |
341 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
342 | length--; | |
343 | continue; | |
344 | default: | |
345 | opsize = *ptr++; | |
346 | if (opsize < 2) /* "silly options" */ | |
347 | return; | |
348 | if (opsize > length) | |
349 | return; /* don't parse partial options */ | |
350 | if (opcode == TCPOPT_MPTCP) | |
cfde141e | 351 | mptcp_parse_option(skb, ptr, opsize, mp_opt); |
cec37a6e PK |
352 | ptr += opsize - 2; |
353 | length -= opsize; | |
354 | } | |
355 | } | |
356 | } | |
357 | ||
cc7972ea CP |
358 | bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
359 | unsigned int *size, struct mptcp_out_options *opts) | |
cec37a6e PK |
360 | { |
361 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
362 | ||
cc7972ea CP |
363 | /* we will use snd_isn to detect first pkt [re]transmission |
364 | * in mptcp_established_options_mp() | |
365 | */ | |
366 | subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; | |
cec37a6e | 367 | if (subflow->request_mptcp) { |
cec37a6e | 368 | opts->suboptions = OPTION_MPTCP_MPC_SYN; |
cec37a6e PK |
369 | *size = TCPOLEN_MPTCP_MPC_SYN; |
370 | return true; | |
ec3edaa7 PK |
371 | } else if (subflow->request_join) { |
372 | pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, | |
373 | subflow->local_nonce); | |
374 | opts->suboptions = OPTION_MPTCP_MPJ_SYN; | |
375 | opts->join_id = subflow->local_id; | |
376 | opts->token = subflow->remote_token; | |
377 | opts->nonce = subflow->local_nonce; | |
378 | opts->backup = subflow->request_bkup; | |
379 | *size = TCPOLEN_MPTCP_MPJ_SYN; | |
380 | return true; | |
cec37a6e PK |
381 | } |
382 | return false; | |
383 | } | |
384 | ||
ec3edaa7 PK |
385 | /* MP_JOIN client subflow must wait for 4th ack before sending any data: |
386 | * TCP can't schedule delack timer before the subflow is fully established. | |
387 | * MPTCP uses the delack timer to do 3rd ack retransmissions | |
388 | */ | |
389 | static void schedule_3rdack_retransmission(struct sock *sk) | |
390 | { | |
391 | struct inet_connection_sock *icsk = inet_csk(sk); | |
392 | struct tcp_sock *tp = tcp_sk(sk); | |
393 | unsigned long timeout; | |
394 | ||
395 | /* reschedule with a timeout above RTT, as we must look only for drop */ | |
396 | if (tp->srtt_us) | |
397 | timeout = tp->srtt_us << 1; | |
398 | else | |
399 | timeout = TCP_TIMEOUT_INIT; | |
400 | ||
401 | WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); | |
402 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
403 | icsk->icsk_ack.timeout = timeout; | |
404 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
405 | } | |
406 | ||
407 | static void clear_3rdack_retransmission(struct sock *sk) | |
408 | { | |
409 | struct inet_connection_sock *icsk = inet_csk(sk); | |
410 | ||
411 | sk_stop_timer(sk, &icsk->icsk_delack_timer); | |
412 | icsk->icsk_ack.timeout = 0; | |
413 | icsk->icsk_ack.ato = 0; | |
414 | icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); | |
415 | } | |
416 | ||
cc7972ea | 417 | static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
d87903b6 | 418 | bool snd_data_fin_enable, |
cc7972ea | 419 | unsigned int *size, |
6d0060f6 MM |
420 | unsigned int remaining, |
421 | struct mptcp_out_options *opts) | |
cec37a6e PK |
422 | { |
423 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
cc7972ea CP |
424 | struct mptcp_ext *mpext; |
425 | unsigned int data_len; | |
426 | ||
ec3edaa7 PK |
427 | /* When skb is not available, we better over-estimate the emitted |
428 | * options len. A full DSS option (28 bytes) is longer than | |
429 | * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so | |
430 | * tell the caller to defer the estimate to | |
431 | * mptcp_established_options_dss(), which will reserve enough space. | |
432 | */ | |
433 | if (!skb) | |
434 | return false; | |
cc7972ea | 435 | |
d87903b6 PA |
436 | /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ |
437 | if (subflow->fully_established || snd_data_fin_enable || | |
438 | subflow->snd_isn != TCP_SKB_CB(skb)->seq || | |
439 | sk->sk_state != TCP_ESTABLISHED) | |
ec3edaa7 PK |
440 | return false; |
441 | ||
442 | if (subflow->mp_capable) { | |
cc7972ea CP |
443 | mpext = mptcp_get_ext(skb); |
444 | data_len = mpext ? mpext->data_len : 0; | |
cec37a6e | 445 | |
cc7972ea CP |
446 | /* we will check ext_copy.data_len in mptcp_write_options() to |
447 | * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and | |
448 | * TCPOLEN_MPTCP_MPC_ACK | |
449 | */ | |
450 | opts->ext_copy.data_len = data_len; | |
cec37a6e PK |
451 | opts->suboptions = OPTION_MPTCP_MPC_ACK; |
452 | opts->sndr_key = subflow->local_key; | |
453 | opts->rcvr_key = subflow->remote_key; | |
cc7972ea CP |
454 | |
455 | /* Section 3.1. | |
456 | * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK | |
457 | * packets that start the first subflow of an MPTCP connection, | |
458 | * as well as the first packet that carries data | |
459 | */ | |
460 | if (data_len > 0) | |
461 | *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); | |
462 | else | |
463 | *size = TCPOLEN_MPTCP_MPC_ACK; | |
464 | ||
465 | pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", | |
466 | subflow, subflow->local_key, subflow->remote_key, | |
467 | data_len); | |
468 | ||
cec37a6e | 469 | return true; |
ec3edaa7 PK |
470 | } else if (subflow->mp_join) { |
471 | opts->suboptions = OPTION_MPTCP_MPJ_ACK; | |
472 | memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); | |
473 | *size = TCPOLEN_MPTCP_MPJ_ACK; | |
474 | pr_debug("subflow=%p", subflow); | |
475 | ||
476 | schedule_3rdack_retransmission(sk); | |
477 | return true; | |
cec37a6e PK |
478 | } |
479 | return false; | |
480 | } | |
481 | ||
6d0060f6 | 482 | static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
9c29e361 | 483 | struct sk_buff *skb, struct mptcp_ext *ext) |
6d0060f6 | 484 | { |
017512a0 PA |
485 | /* The write_seq value has already been incremented, so the actual |
486 | * sequence number for the DATA_FIN is one less. | |
487 | */ | |
488 | u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; | |
7279da61 | 489 | |
9c29e361 | 490 | if (!ext->use_map || !skb->len) { |
6d0060f6 MM |
491 | /* RFC6824 requires a DSS mapping with specific values |
492 | * if DATA_FIN is set but no data payload is mapped | |
493 | */ | |
6d37a0b8 | 494 | ext->data_fin = 1; |
6d0060f6 MM |
495 | ext->use_map = 1; |
496 | ext->dsn64 = 1; | |
017512a0 | 497 | ext->data_seq = data_fin_tx_seq; |
6d0060f6 MM |
498 | ext->subflow_seq = 0; |
499 | ext->data_len = 1; | |
7279da61 | 500 | } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { |
6d37a0b8 MM |
501 | /* If there's an existing DSS mapping and it is the |
502 | * final mapping, DATA_FIN consumes 1 additional byte of | |
503 | * mapping space. | |
6d0060f6 | 504 | */ |
6d37a0b8 | 505 | ext->data_fin = 1; |
6d0060f6 MM |
506 | ext->data_len++; |
507 | } | |
508 | } | |
509 | ||
510 | static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, | |
d87903b6 | 511 | bool snd_data_fin_enable, |
6d0060f6 MM |
512 | unsigned int *size, |
513 | unsigned int remaining, | |
514 | struct mptcp_out_options *opts) | |
515 | { | |
516 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
7279da61 | 517 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
6d0060f6 MM |
518 | unsigned int dss_size = 0; |
519 | struct mptcp_ext *mpext; | |
6d0060f6 | 520 | unsigned int ack_size; |
d22f4988 | 521 | bool ret = false; |
d87903b6 | 522 | u64 ack_seq; |
6d0060f6 | 523 | |
0bac966a | 524 | mpext = skb ? mptcp_get_ext(skb) : NULL; |
6d0060f6 | 525 | |
7279da61 | 526 | if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { |
6d0060f6 MM |
527 | unsigned int map_size; |
528 | ||
529 | map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; | |
530 | ||
531 | remaining -= map_size; | |
532 | dss_size = map_size; | |
533 | if (mpext) | |
534 | opts->ext_copy = *mpext; | |
535 | ||
7279da61 | 536 | if (skb && snd_data_fin_enable) |
9c29e361 | 537 | mptcp_write_data_fin(subflow, skb, &opts->ext_copy); |
d22f4988 CP |
538 | ret = true; |
539 | } | |
540 | ||
2398e399 PA |
541 | /* passive sockets msk will set the 'can_ack' after accept(), even |
542 | * if the first subflow may have the already the remote key handy | |
543 | */ | |
d22f4988 | 544 | opts->ext_copy.use_ack = 0; |
dc093db5 | 545 | if (!READ_ONCE(msk->can_ack)) { |
d22f4988 CP |
546 | *size = ALIGN(dss_size, 4); |
547 | return ret; | |
6d0060f6 MM |
548 | } |
549 | ||
e3859603 | 550 | ack_seq = READ_ONCE(msk->ack_seq); |
37198e93 | 551 | if (READ_ONCE(msk->use_64bit_ack)) { |
a0c1d0ea | 552 | ack_size = TCPOLEN_MPTCP_DSS_ACK64; |
e3859603 | 553 | opts->ext_copy.data_ack = ack_seq; |
a0c1d0ea CP |
554 | opts->ext_copy.ack64 = 1; |
555 | } else { | |
556 | ack_size = TCPOLEN_MPTCP_DSS_ACK32; | |
e3859603 | 557 | opts->ext_copy.data_ack32 = (uint32_t)ack_seq; |
a0c1d0ea CP |
558 | opts->ext_copy.ack64 = 0; |
559 | } | |
560 | opts->ext_copy.use_ack = 1; | |
ea4ca586 | 561 | WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); |
6d0060f6 MM |
562 | |
563 | /* Add kind/length/subtype/flag overhead if mapping is not populated */ | |
564 | if (dss_size == 0) | |
565 | ack_size += TCPOLEN_MPTCP_DSS_BASE; | |
566 | ||
567 | dss_size += ack_size; | |
568 | ||
6d0060f6 MM |
569 | *size = ALIGN(dss_size, 4); |
570 | return true; | |
571 | } | |
572 | ||
3df523ab | 573 | static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id, |
13832ae2 | 574 | struct in_addr *addr, u16 port) |
3df523ab | 575 | { |
bd697222 | 576 | u8 hmac[SHA256_DIGEST_SIZE]; |
3df523ab PK |
577 | u8 msg[7]; |
578 | ||
579 | msg[0] = addr_id; | |
580 | memcpy(&msg[1], &addr->s_addr, 4); | |
13832ae2 DC |
581 | msg[5] = port >> 8; |
582 | msg[6] = port & 0xFF; | |
3df523ab PK |
583 | |
584 | mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac); | |
585 | ||
bd697222 | 586 | return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
3df523ab PK |
587 | } |
588 | ||
589 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
590 | static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id, | |
13832ae2 | 591 | struct in6_addr *addr, u16 port) |
3df523ab | 592 | { |
bd697222 | 593 | u8 hmac[SHA256_DIGEST_SIZE]; |
3df523ab PK |
594 | u8 msg[19]; |
595 | ||
596 | msg[0] = addr_id; | |
597 | memcpy(&msg[1], &addr->s6_addr, 16); | |
13832ae2 DC |
598 | msg[17] = port >> 8; |
599 | msg[18] = port & 0xFF; | |
3df523ab PK |
600 | |
601 | mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac); | |
602 | ||
bd697222 | 603 | return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
3df523ab PK |
604 | } |
605 | #endif | |
606 | ||
84dfe367 | 607 | static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, |
f643b803 GT |
608 | unsigned int *size, |
609 | unsigned int remaining, | |
610 | struct mptcp_out_options *opts) | |
3df523ab PK |
611 | { |
612 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
613 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
84dfe367 GT |
614 | bool drop_other_suboptions = false; |
615 | unsigned int opt_size = *size; | |
1b1c7a0e | 616 | struct mptcp_addr_info saddr; |
6a6c05a8 | 617 | bool echo; |
4a2777a8 | 618 | bool port; |
1b1c7a0e | 619 | int len; |
3df523ab | 620 | |
fbe0f87a GT |
621 | if ((mptcp_pm_should_add_signal_ipv6(msk) || |
622 | mptcp_pm_should_add_signal_port(msk)) && | |
84dfe367 GT |
623 | skb && skb_is_tcp_pure_ack(skb)) { |
624 | pr_debug("drop other suboptions"); | |
625 | opts->suboptions = 0; | |
3ae32c07 GT |
626 | opts->ext_copy.use_ack = 0; |
627 | opts->ext_copy.use_map = 0; | |
84dfe367 GT |
628 | remaining += opt_size; |
629 | drop_other_suboptions = true; | |
630 | } | |
631 | ||
f643b803 | 632 | if (!mptcp_pm_should_add_signal(msk) || |
4a2777a8 | 633 | !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port))) |
1b1c7a0e PK |
634 | return false; |
635 | ||
4a2777a8 | 636 | len = mptcp_add_addr_len(saddr.family, echo, port); |
1b1c7a0e PK |
637 | if (remaining < len) |
638 | return false; | |
3df523ab | 639 | |
1b1c7a0e | 640 | *size = len; |
84dfe367 GT |
641 | if (drop_other_suboptions) |
642 | *size -= opt_size; | |
1b1c7a0e | 643 | opts->addr_id = saddr.id; |
4a2777a8 GT |
644 | if (port) |
645 | opts->port = ntohs(saddr.port); | |
1b1c7a0e | 646 | if (saddr.family == AF_INET) { |
3df523ab | 647 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR; |
1b1c7a0e | 648 | opts->addr = saddr.addr; |
6a6c05a8 GT |
649 | if (!echo) { |
650 | opts->ahmac = add_addr_generate_hmac(msk->local_key, | |
651 | msk->remote_key, | |
652 | opts->addr_id, | |
13832ae2 DC |
653 | &opts->addr, |
654 | opts->port); | |
6a6c05a8 | 655 | } |
3df523ab PK |
656 | } |
657 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1b1c7a0e | 658 | else if (saddr.family == AF_INET6) { |
3df523ab | 659 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR6; |
1b1c7a0e | 660 | opts->addr6 = saddr.addr6; |
6a6c05a8 GT |
661 | if (!echo) { |
662 | opts->ahmac = add_addr6_generate_hmac(msk->local_key, | |
663 | msk->remote_key, | |
664 | opts->addr_id, | |
13832ae2 DC |
665 | &opts->addr6, |
666 | opts->port); | |
6a6c05a8 | 667 | } |
3df523ab PK |
668 | } |
669 | #endif | |
4a2777a8 GT |
670 | pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", |
671 | opts->addr_id, opts->ahmac, echo, opts->port); | |
3df523ab PK |
672 | |
673 | return true; | |
674 | } | |
675 | ||
5cb104ae GT |
676 | static bool mptcp_established_options_rm_addr(struct sock *sk, |
677 | unsigned int *size, | |
678 | unsigned int remaining, | |
679 | struct mptcp_out_options *opts) | |
680 | { | |
681 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
682 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
6445e17a GT |
683 | struct mptcp_rm_list rm_list; |
684 | int i, len; | |
5cb104ae GT |
685 | |
686 | if (!mptcp_pm_should_rm_signal(msk) || | |
6445e17a | 687 | !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list))) |
5cb104ae GT |
688 | return false; |
689 | ||
6445e17a GT |
690 | len = mptcp_rm_addr_len(&rm_list); |
691 | if (len < 0) | |
692 | return false; | |
693 | if (remaining < len) | |
5cb104ae GT |
694 | return false; |
695 | ||
6445e17a | 696 | *size = len; |
5cb104ae | 697 | opts->suboptions |= OPTION_MPTCP_RM_ADDR; |
6445e17a | 698 | opts->rm_list = rm_list; |
5cb104ae | 699 | |
6445e17a GT |
700 | for (i = 0; i < opts->rm_list.nr; i++) |
701 | pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]); | |
5cb104ae GT |
702 | |
703 | return true; | |
704 | } | |
705 | ||
06706542 GT |
706 | static bool mptcp_established_options_mp_prio(struct sock *sk, |
707 | unsigned int *size, | |
708 | unsigned int remaining, | |
709 | struct mptcp_out_options *opts) | |
710 | { | |
711 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
712 | ||
713 | if (!subflow->send_mp_prio) | |
714 | return false; | |
715 | ||
ec99a470 DC |
716 | /* account for the trailing 'nop' option */ |
717 | if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) | |
06706542 GT |
718 | return false; |
719 | ||
ec99a470 | 720 | *size = TCPOLEN_MPTCP_PRIO_ALIGN; |
06706542 GT |
721 | opts->suboptions |= OPTION_MPTCP_PRIO; |
722 | opts->backup = subflow->request_bkup; | |
723 | ||
724 | pr_debug("prio=%d", opts->backup); | |
725 | ||
726 | return true; | |
727 | } | |
728 | ||
6d0060f6 MM |
729 | bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, |
730 | unsigned int *size, unsigned int remaining, | |
731 | struct mptcp_out_options *opts) | |
732 | { | |
d87903b6 PA |
733 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
734 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
6d0060f6 | 735 | unsigned int opt_size = 0; |
d87903b6 | 736 | bool snd_data_fin; |
6d0060f6 MM |
737 | bool ret = false; |
738 | ||
3df523ab PK |
739 | opts->suboptions = 0; |
740 | ||
d87903b6 | 741 | if (unlikely(__mptcp_check_fallback(msk))) |
e1ff9e82 DC |
742 | return false; |
743 | ||
d5824847 PA |
744 | /* prevent adding of any MPTCP related options on reset packet |
745 | * until we support MP_TCPRST/MP_FASTCLOSE | |
746 | */ | |
747 | if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) | |
748 | return false; | |
749 | ||
d87903b6 PA |
750 | snd_data_fin = mptcp_data_fin_enabled(msk); |
751 | if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts)) | |
6d0060f6 | 752 | ret = true; |
d87903b6 | 753 | else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) |
6d0060f6 MM |
754 | ret = true; |
755 | ||
756 | /* we reserved enough space for the above options, and exceeding the | |
757 | * TCP option space would be fatal | |
758 | */ | |
759 | if (WARN_ON_ONCE(opt_size > remaining)) | |
760 | return false; | |
761 | ||
762 | *size += opt_size; | |
763 | remaining -= opt_size; | |
84dfe367 | 764 | if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { |
3df523ab PK |
765 | *size += opt_size; |
766 | remaining -= opt_size; | |
767 | ret = true; | |
5cb104ae GT |
768 | } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { |
769 | *size += opt_size; | |
770 | remaining -= opt_size; | |
771 | ret = true; | |
3df523ab | 772 | } |
6d0060f6 | 773 | |
06706542 GT |
774 | if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) { |
775 | *size += opt_size; | |
776 | remaining -= opt_size; | |
777 | ret = true; | |
778 | } | |
779 | ||
6d0060f6 MM |
780 | return ret; |
781 | } | |
782 | ||
cec37a6e PK |
783 | bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
784 | struct mptcp_out_options *opts) | |
785 | { | |
786 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
787 | ||
788 | if (subflow_req->mp_capable) { | |
789 | opts->suboptions = OPTION_MPTCP_MPC_SYNACK; | |
790 | opts->sndr_key = subflow_req->local_key; | |
791 | *size = TCPOLEN_MPTCP_MPC_SYNACK; | |
792 | pr_debug("subflow_req=%p, local_key=%llu", | |
793 | subflow_req, subflow_req->local_key); | |
794 | return true; | |
f296234c PK |
795 | } else if (subflow_req->mp_join) { |
796 | opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; | |
797 | opts->backup = subflow_req->backup; | |
798 | opts->join_id = subflow_req->local_id; | |
799 | opts->thmac = subflow_req->thmac; | |
800 | opts->nonce = subflow_req->local_nonce; | |
801 | pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", | |
802 | subflow_req, opts->backup, opts->join_id, | |
803 | opts->thmac, opts->nonce); | |
804 | *size = TCPOLEN_MPTCP_MPJ_SYNACK; | |
805 | return true; | |
cec37a6e PK |
806 | } |
807 | return false; | |
808 | } | |
809 | ||
d5824847 | 810 | static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, |
f296234c | 811 | struct mptcp_subflow_context *subflow, |
0be534f5 PA |
812 | struct sk_buff *skb, |
813 | struct mptcp_options_received *mp_opt) | |
d22f4988 CP |
814 | { |
815 | /* here we can process OoO, in-window pkts, only in-sequence 4th ack | |
f296234c | 816 | * will make the subflow fully established |
d22f4988 | 817 | */ |
f296234c PK |
818 | if (likely(subflow->fully_established)) { |
819 | /* on passive sockets, check for 3rd ack retransmission | |
820 | * note that msk is always set by subflow_syn_recv_sock() | |
821 | * for mp_join subflows | |
822 | */ | |
823 | if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && | |
824 | TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && | |
825 | subflow->mp_join && mp_opt->mp_join && | |
826 | READ_ONCE(msk->pm.server_side)) | |
d5824847 | 827 | tcp_send_ack(ssk); |
f296234c PK |
828 | goto fully_established; |
829 | } | |
830 | ||
d5824847 PA |
831 | /* we must process OoO packets before the first subflow is fully |
832 | * established. OoO packets are instead a protocol violation | |
833 | * for MP_JOIN subflows as the peer must not send any data | |
834 | * before receiving the forth ack - cfr. RFC 8684 section 3.2. | |
f296234c | 835 | */ |
d5824847 PA |
836 | if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { |
837 | if (subflow->mp_join) | |
838 | goto reset; | |
f296234c | 839 | return subflow->mp_capable; |
d5824847 | 840 | } |
d22f4988 | 841 | |
5a91e32b | 842 | if (mp_opt->dss && mp_opt->use_ack) { |
f296234c PK |
843 | /* subflows are fully established as soon as we get any |
844 | * additional ack. | |
845 | */ | |
0be534f5 | 846 | subflow->fully_established = 1; |
b93df08c | 847 | WRITE_ONCE(msk->fully_established, true); |
f296234c PK |
848 | goto fully_established; |
849 | } | |
d22f4988 | 850 | |
84dfe367 GT |
851 | if (mp_opt->add_addr) { |
852 | WRITE_ONCE(msk->fully_established, true); | |
853 | return true; | |
854 | } | |
855 | ||
d22f4988 | 856 | /* If the first established packet does not contain MP_CAPABLE + data |
d5824847 PA |
857 | * then fallback to TCP. Fallback scenarios requires a reset for |
858 | * MP_JOIN subflows. | |
d22f4988 CP |
859 | */ |
860 | if (!mp_opt->mp_capable) { | |
d5824847 PA |
861 | if (subflow->mp_join) |
862 | goto reset; | |
d22f4988 | 863 | subflow->mp_capable = 0; |
e1ff9e82 DC |
864 | pr_fallback(msk); |
865 | __mptcp_do_fallback(msk); | |
d22f4988 CP |
866 | return false; |
867 | } | |
f296234c | 868 | |
d6085fe1 PA |
869 | if (unlikely(!READ_ONCE(msk->pm.server_side))) |
870 | pr_warn_once("bogus mpc option on established client sk"); | |
b93df08c | 871 | mptcp_subflow_fully_established(subflow, mp_opt); |
f296234c PK |
872 | |
873 | fully_established: | |
5b950ff4 PA |
874 | /* if the subflow is not already linked into the conn_list, we can't |
875 | * notify the PM: this subflow is still on the listener queue | |
876 | * and the PM possibly acquiring the subflow lock could race with | |
877 | * the listener close | |
878 | */ | |
879 | if (likely(subflow->pm_notified) || list_empty(&subflow->node)) | |
f296234c PK |
880 | return true; |
881 | ||
882 | subflow->pm_notified = 1; | |
ec3edaa7 | 883 | if (subflow->mp_join) { |
d5824847 | 884 | clear_3rdack_retransmission(ssk); |
62535200 | 885 | mptcp_pm_subflow_established(msk); |
ec3edaa7 | 886 | } else { |
6c714f1b | 887 | mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC); |
ec3edaa7 | 888 | } |
d22f4988 | 889 | return true; |
d5824847 PA |
890 | |
891 | reset: | |
892 | mptcp_subflow_reset(ssk); | |
893 | return false; | |
d22f4988 CP |
894 | } |
895 | ||
cc9d2566 PA |
896 | static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) |
897 | { | |
898 | u32 old_ack32, cur_ack32; | |
899 | ||
900 | if (use_64bit) | |
901 | return cur_ack; | |
902 | ||
903 | old_ack32 = (u32)old_ack; | |
904 | cur_ack32 = (u32)cur_ack; | |
905 | cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; | |
906 | if (unlikely(before(cur_ack32, old_ack32))) | |
907 | return cur_ack + (1LL << 32); | |
908 | return cur_ack; | |
909 | } | |
910 | ||
6f8a612a | 911 | static void ack_update_msk(struct mptcp_sock *msk, |
6e628cd3 | 912 | struct sock *ssk, |
6f8a612a | 913 | struct mptcp_options_received *mp_opt) |
cc9d2566 | 914 | { |
7439d687 | 915 | u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); |
6f8a612a | 916 | struct sock *sk = (struct sock *)msk; |
7439d687 PA |
917 | u64 old_snd_una; |
918 | ||
919 | mptcp_data_lock(sk); | |
cc9d2566 PA |
920 | |
921 | /* avoid ack expansion on update conflict, to reduce the risk of | |
922 | * wrongly expanding to a future ack sequence number, which is way | |
923 | * more dangerous than missing an ack | |
924 | */ | |
7439d687 | 925 | old_snd_una = msk->snd_una; |
cc9d2566 PA |
926 | new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); |
927 | ||
928 | /* ACK for data not even sent yet? Ignore. */ | |
eaa2ffab | 929 | if (after64(new_snd_una, snd_nxt)) |
cc9d2566 PA |
930 | new_snd_una = old_snd_una; |
931 | ||
6f8a612a FW |
932 | new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; |
933 | ||
219d0499 | 934 | if (after64(new_wnd_end, msk->wnd_end)) |
7439d687 | 935 | msk->wnd_end = new_wnd_end; |
219d0499 PA |
936 | |
937 | /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ | |
d09d818e | 938 | if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) |
219d0499 | 939 | __mptcp_check_push(sk, ssk); |
6f8a612a | 940 | |
7439d687 PA |
941 | if (after64(new_snd_una, old_snd_una)) { |
942 | msk->snd_una = new_snd_una; | |
943 | __mptcp_data_acked(sk); | |
cc9d2566 | 944 | } |
7439d687 | 945 | mptcp_data_unlock(sk); |
cc9d2566 PA |
946 | } |
947 | ||
1a49b2c2 | 948 | bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) |
3721b9b6 MM |
949 | { |
950 | /* Skip if DATA_FIN was already received. | |
951 | * If updating simultaneously with the recvmsg loop, values | |
952 | * should match. If they mismatch, the peer is misbehaving and | |
953 | * we will prefer the most recent information. | |
954 | */ | |
955 | if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first)) | |
956 | return false; | |
957 | ||
1a49b2c2 MM |
958 | WRITE_ONCE(msk->rcv_data_fin_seq, |
959 | expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); | |
3721b9b6 MM |
960 | WRITE_ONCE(msk->rcv_data_fin, 1); |
961 | ||
962 | return true; | |
963 | } | |
964 | ||
1b1c7a0e PK |
965 | static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
966 | struct mptcp_options_received *mp_opt) | |
967 | { | |
968 | u64 hmac = 0; | |
969 | ||
970 | if (mp_opt->echo) | |
971 | return true; | |
972 | ||
973 | if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) | |
974 | hmac = add_addr_generate_hmac(msk->remote_key, | |
975 | msk->local_key, | |
13832ae2 DC |
976 | mp_opt->addr_id, &mp_opt->addr, |
977 | mp_opt->port); | |
1b1c7a0e PK |
978 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
979 | else | |
980 | hmac = add_addr6_generate_hmac(msk->remote_key, | |
981 | msk->local_key, | |
13832ae2 DC |
982 | mp_opt->addr_id, &mp_opt->addr6, |
983 | mp_opt->port); | |
1b1c7a0e PK |
984 | #endif |
985 | ||
986 | pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", | |
987 | msk, (unsigned long long)hmac, | |
988 | (unsigned long long)mp_opt->ahmac); | |
989 | ||
990 | return hmac == mp_opt->ahmac; | |
991 | } | |
992 | ||
77d0cab9 | 993 | void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) |
648ef4b8 | 994 | { |
d22f4988 | 995 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
1b1c7a0e | 996 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
cfde141e | 997 | struct mptcp_options_received mp_opt; |
648ef4b8 MM |
998 | struct mptcp_ext *mpext; |
999 | ||
6e628cd3 PA |
1000 | if (__mptcp_check_fallback(msk)) { |
1001 | /* Keep it simple and unconditionally trigger send data cleanup and | |
1002 | * pending queue spooling. We will need to acquire the data lock | |
1003 | * for more accurate checks, and once the lock is acquired, such | |
1004 | * helpers are cheap. | |
1005 | */ | |
1006 | mptcp_data_lock(subflow->conn); | |
219d0499 PA |
1007 | if (sk_stream_memory_free(sk)) |
1008 | __mptcp_check_push(subflow->conn, sk); | |
6e628cd3 PA |
1009 | __mptcp_data_acked(subflow->conn); |
1010 | mptcp_data_unlock(subflow->conn); | |
e1ff9e82 | 1011 | return; |
6e628cd3 | 1012 | } |
e1ff9e82 | 1013 | |
cfde141e PA |
1014 | mptcp_get_options(skb, &mp_opt); |
1015 | if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) | |
d22f4988 | 1016 | return; |
648ef4b8 | 1017 | |
50c504a2 FW |
1018 | if (mp_opt.fastclose && |
1019 | msk->local_key == mp_opt.rcvr_key) { | |
1020 | WRITE_ONCE(msk->rcv_fastclose, true); | |
1021 | mptcp_schedule_work((struct sock *)msk); | |
1022 | } | |
1023 | ||
cfde141e | 1024 | if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { |
1b1c7a0e PK |
1025 | struct mptcp_addr_info addr; |
1026 | ||
cfde141e PA |
1027 | addr.port = htons(mp_opt.port); |
1028 | addr.id = mp_opt.addr_id; | |
1029 | if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) { | |
1b1c7a0e | 1030 | addr.family = AF_INET; |
cfde141e | 1031 | addr.addr = mp_opt.addr; |
1b1c7a0e PK |
1032 | } |
1033 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
cfde141e | 1034 | else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) { |
1b1c7a0e | 1035 | addr.family = AF_INET6; |
cfde141e | 1036 | addr.addr6 = mp_opt.addr6; |
1b1c7a0e PK |
1037 | } |
1038 | #endif | |
a877de06 | 1039 | if (!mp_opt.echo) { |
1b1c7a0e | 1040 | mptcp_pm_add_addr_received(msk, &addr); |
a877de06 GT |
1041 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); |
1042 | } else { | |
00cfd77b | 1043 | mptcp_pm_del_add_timer(msk, &addr); |
a877de06 GT |
1044 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); |
1045 | } | |
2fbdd9ea GT |
1046 | |
1047 | if (mp_opt.port) | |
1048 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD); | |
1049 | ||
cfde141e | 1050 | mp_opt.add_addr = 0; |
1b1c7a0e PK |
1051 | } |
1052 | ||
d0876b22 | 1053 | if (mp_opt.rm_addr) { |
5c4a824d | 1054 | mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list); |
d0876b22 GT |
1055 | mp_opt.rm_addr = 0; |
1056 | } | |
1057 | ||
40453a5c GT |
1058 | if (mp_opt.mp_prio) { |
1059 | mptcp_pm_mp_prio_received(sk, mp_opt.backup); | |
0be2ac28 | 1060 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX); |
40453a5c GT |
1061 | mp_opt.mp_prio = 0; |
1062 | } | |
1063 | ||
cfde141e | 1064 | if (!mp_opt.dss) |
648ef4b8 MM |
1065 | return; |
1066 | ||
cc9d2566 PA |
1067 | /* we can't wait for recvmsg() to update the ack_seq, otherwise |
1068 | * monodirectional flows will stuck | |
1069 | */ | |
cfde141e | 1070 | if (mp_opt.use_ack) |
6f8a612a | 1071 | ack_update_msk(msk, sk, &mp_opt); |
cc9d2566 | 1072 | |
06827b34 MM |
1073 | /* Zero-data-length packets are dropped by the caller and not |
1074 | * propagated to the MPTCP layer, so the skb extension does not | |
1075 | * need to be allocated or populated. DATA_FIN information, if | |
1076 | * present, needs to be updated here before the skb is freed. | |
43b54c6e MM |
1077 | */ |
1078 | if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { | |
1079 | if (mp_opt.data_fin && mp_opt.data_len == 1 && | |
1a49b2c2 | 1080 | mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && |
43b54c6e MM |
1081 | schedule_work(&msk->work)) |
1082 | sock_hold(subflow->conn); | |
06827b34 MM |
1083 | |
1084 | return; | |
43b54c6e MM |
1085 | } |
1086 | ||
648ef4b8 MM |
1087 | mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
1088 | if (!mpext) | |
1089 | return; | |
1090 | ||
1091 | memset(mpext, 0, sizeof(*mpext)); | |
1092 | ||
cfde141e PA |
1093 | if (mp_opt.use_map) { |
1094 | if (mp_opt.mpc_map) { | |
cc7972ea CP |
1095 | /* this is an MP_CAPABLE carrying MPTCP data |
1096 | * we know this map the first chunk of data | |
1097 | */ | |
1098 | mptcp_crypto_key_sha(subflow->remote_key, NULL, | |
1099 | &mpext->data_seq); | |
1100 | mpext->data_seq++; | |
1101 | mpext->subflow_seq = 1; | |
1102 | mpext->dsn64 = 1; | |
1103 | mpext->mpc_map = 1; | |
a77895db | 1104 | mpext->data_fin = 0; |
cc7972ea | 1105 | } else { |
cfde141e PA |
1106 | mpext->data_seq = mp_opt.data_seq; |
1107 | mpext->subflow_seq = mp_opt.subflow_seq; | |
1108 | mpext->dsn64 = mp_opt.dsn64; | |
1109 | mpext->data_fin = mp_opt.data_fin; | |
cc7972ea | 1110 | } |
cfde141e | 1111 | mpext->data_len = mp_opt.data_len; |
648ef4b8 | 1112 | mpext->use_map = 1; |
648ef4b8 | 1113 | } |
648ef4b8 MM |
1114 | } |
1115 | ||
fa3fe2b1 FW |
1116 | static void mptcp_set_rwin(const struct tcp_sock *tp) |
1117 | { | |
1118 | const struct sock *ssk = (const struct sock *)tp; | |
1119 | const struct mptcp_subflow_context *subflow; | |
1120 | struct mptcp_sock *msk; | |
1121 | u64 ack_seq; | |
1122 | ||
1123 | subflow = mptcp_subflow_ctx(ssk); | |
1124 | msk = mptcp_sk(subflow->conn); | |
1125 | ||
1126 | ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; | |
1127 | ||
1128 | if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) | |
1129 | WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); | |
1130 | } | |
1131 | ||
1132 | void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, | |
1133 | struct mptcp_out_options *opts) | |
eda7acdd | 1134 | { |
cc7972ea | 1135 | if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | |
eda7acdd PK |
1136 | OPTION_MPTCP_MPC_ACK) & opts->suboptions) { |
1137 | u8 len; | |
1138 | ||
1139 | if (OPTION_MPTCP_MPC_SYN & opts->suboptions) | |
1140 | len = TCPOLEN_MPTCP_MPC_SYN; | |
cec37a6e PK |
1141 | else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) |
1142 | len = TCPOLEN_MPTCP_MPC_SYNACK; | |
cc7972ea CP |
1143 | else if (opts->ext_copy.data_len) |
1144 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
eda7acdd PK |
1145 | else |
1146 | len = TCPOLEN_MPTCP_MPC_ACK; | |
1147 | ||
3df523ab PK |
1148 | *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, |
1149 | MPTCP_SUPPORTED_VERSION, | |
1150 | MPTCP_CAP_HMAC_SHA256); | |
cc7972ea CP |
1151 | |
1152 | if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & | |
1153 | opts->suboptions)) | |
1154 | goto mp_capable_done; | |
1155 | ||
eda7acdd PK |
1156 | put_unaligned_be64(opts->sndr_key, ptr); |
1157 | ptr += 2; | |
cc7972ea CP |
1158 | if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
1159 | goto mp_capable_done; | |
1160 | ||
1161 | put_unaligned_be64(opts->rcvr_key, ptr); | |
1162 | ptr += 2; | |
1163 | if (!opts->ext_copy.data_len) | |
1164 | goto mp_capable_done; | |
1165 | ||
1166 | put_unaligned_be32(opts->ext_copy.data_len << 16 | | |
1167 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
1168 | ptr += 1; | |
eda7acdd | 1169 | } |
6d0060f6 | 1170 | |
cc7972ea | 1171 | mp_capable_done: |
e1ef6832 GT |
1172 | if ((OPTION_MPTCP_ADD_ADDR |
1173 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1174 | | OPTION_MPTCP_ADD_ADDR6 | |
1175 | #endif | |
1176 | ) & opts->suboptions) { | |
6eb3d1e3 GT |
1177 | u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; |
1178 | u8 echo = MPTCP_ADDR_ECHO; | |
1179 | ||
e1ef6832 GT |
1180 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
1181 | if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) | |
1182 | len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; | |
1183 | #endif | |
1184 | ||
22fb85ff GT |
1185 | if (opts->port) |
1186 | len += TCPOLEN_MPTCP_PORT_LEN; | |
1187 | ||
3df523ab | 1188 | if (opts->ahmac) { |
6eb3d1e3 GT |
1189 | len += sizeof(opts->ahmac); |
1190 | echo = 0; | |
3df523ab | 1191 | } |
3df523ab | 1192 | |
6eb3d1e3 GT |
1193 | *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, |
1194 | len, echo, opts->addr_id); | |
e1ef6832 GT |
1195 | if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { |
1196 | memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4); | |
1197 | ptr += 1; | |
3df523ab | 1198 | } |
3df523ab | 1199 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
e1ef6832 GT |
1200 | else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) { |
1201 | memcpy((u8 *)ptr, opts->addr6.s6_addr, 16); | |
1202 | ptr += 4; | |
3df523ab | 1203 | } |
3df523ab PK |
1204 | #endif |
1205 | ||
22fb85ff GT |
1206 | if (!opts->port) { |
1207 | if (opts->ahmac) { | |
1208 | put_unaligned_be64(opts->ahmac, ptr); | |
1209 | ptr += 2; | |
1210 | } | |
1211 | } else { | |
1212 | if (opts->ahmac) { | |
1213 | u8 *bptr = (u8 *)ptr; | |
1214 | ||
1215 | put_unaligned_be16(opts->port, bptr); | |
1216 | bptr += 2; | |
1217 | put_unaligned_be64(opts->ahmac, bptr); | |
1218 | bptr += 8; | |
1219 | put_unaligned_be16(TCPOPT_NOP << 8 | | |
1220 | TCPOPT_NOP, bptr); | |
1221 | ||
1222 | ptr += 3; | |
1223 | } else { | |
1224 | put_unaligned_be32(opts->port << 16 | | |
1225 | TCPOPT_NOP << 8 | | |
1226 | TCPOPT_NOP, ptr); | |
1227 | ptr += 1; | |
1228 | } | |
3df523ab PK |
1229 | } |
1230 | } | |
3df523ab PK |
1231 | |
1232 | if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { | |
6445e17a GT |
1233 | u8 i = 1; |
1234 | ||
3df523ab | 1235 | *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, |
6445e17a GT |
1236 | TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, |
1237 | 0, opts->rm_list.ids[0]); | |
1238 | ||
1239 | while (i < opts->rm_list.nr) { | |
1240 | u8 id1, id2, id3, id4; | |
1241 | ||
1242 | id1 = opts->rm_list.ids[i]; | |
1243 | id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; | |
1244 | id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; | |
1245 | id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; | |
1246 | put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr); | |
1247 | ptr += 1; | |
1248 | i += 4; | |
1249 | } | |
3df523ab PK |
1250 | } |
1251 | ||
06706542 GT |
1252 | if (OPTION_MPTCP_PRIO & opts->suboptions) { |
1253 | const struct sock *ssk = (const struct sock *)tp; | |
1254 | struct mptcp_subflow_context *subflow; | |
1255 | ||
1256 | subflow = mptcp_subflow_ctx(ssk); | |
1257 | subflow->send_mp_prio = 0; | |
1258 | ||
1259 | *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, | |
1260 | TCPOLEN_MPTCP_PRIO, | |
1261 | opts->backup, TCPOPT_NOP); | |
1262 | } | |
1263 | ||
ec3edaa7 PK |
1264 | if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { |
1265 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1266 | TCPOLEN_MPTCP_MPJ_SYN, | |
1267 | opts->backup, opts->join_id); | |
1268 | put_unaligned_be32(opts->token, ptr); | |
1269 | ptr += 1; | |
1270 | put_unaligned_be32(opts->nonce, ptr); | |
1271 | ptr += 1; | |
1272 | } | |
1273 | ||
f296234c PK |
1274 | if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { |
1275 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1276 | TCPOLEN_MPTCP_MPJ_SYNACK, | |
1277 | opts->backup, opts->join_id); | |
1278 | put_unaligned_be64(opts->thmac, ptr); | |
1279 | ptr += 2; | |
1280 | put_unaligned_be32(opts->nonce, ptr); | |
1281 | ptr += 1; | |
1282 | } | |
1283 | ||
ec3edaa7 PK |
1284 | if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { |
1285 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1286 | TCPOLEN_MPTCP_MPJ_ACK, 0, 0); | |
1287 | memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); | |
1288 | ptr += 5; | |
1289 | } | |
1290 | ||
6d0060f6 MM |
1291 | if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { |
1292 | struct mptcp_ext *mpext = &opts->ext_copy; | |
1293 | u8 len = TCPOLEN_MPTCP_DSS_BASE; | |
1294 | u8 flags = 0; | |
1295 | ||
1296 | if (mpext->use_ack) { | |
a0c1d0ea CP |
1297 | flags = MPTCP_DSS_HAS_ACK; |
1298 | if (mpext->ack64) { | |
1299 | len += TCPOLEN_MPTCP_DSS_ACK64; | |
1300 | flags |= MPTCP_DSS_ACK64; | |
1301 | } else { | |
1302 | len += TCPOLEN_MPTCP_DSS_ACK32; | |
1303 | } | |
6d0060f6 MM |
1304 | } |
1305 | ||
1306 | if (mpext->use_map) { | |
1307 | len += TCPOLEN_MPTCP_DSS_MAP64; | |
1308 | ||
1309 | /* Use only 64-bit mapping flags for now, add | |
1310 | * support for optional 32-bit mappings later. | |
1311 | */ | |
1312 | flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; | |
1313 | if (mpext->data_fin) | |
1314 | flags |= MPTCP_DSS_DATA_FIN; | |
1315 | } | |
1316 | ||
3df523ab | 1317 | *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); |
6d0060f6 MM |
1318 | |
1319 | if (mpext->use_ack) { | |
a0c1d0ea CP |
1320 | if (mpext->ack64) { |
1321 | put_unaligned_be64(mpext->data_ack, ptr); | |
1322 | ptr += 2; | |
1323 | } else { | |
1324 | put_unaligned_be32(mpext->data_ack32, ptr); | |
1325 | ptr += 1; | |
1326 | } | |
6d0060f6 MM |
1327 | } |
1328 | ||
1329 | if (mpext->use_map) { | |
1330 | put_unaligned_be64(mpext->data_seq, ptr); | |
1331 | ptr += 2; | |
1332 | put_unaligned_be32(mpext->subflow_seq, ptr); | |
1333 | ptr += 1; | |
1334 | put_unaligned_be32(mpext->data_len << 16 | | |
1335 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
1336 | } | |
1337 | } | |
fa3fe2b1 FW |
1338 | |
1339 | if (tp) | |
1340 | mptcp_set_rwin(tp); | |
eda7acdd | 1341 | } |