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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; | |
29 | ||
30 | switch (subtype) { | |
31 | case MPTCPOPT_MP_CAPABLE: | |
cc7972ea CP |
32 | /* strict size checking */ |
33 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { | |
34 | if (skb->len > tcp_hdr(skb)->doff << 2) | |
35 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
36 | else | |
37 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK; | |
38 | } else { | |
39 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) | |
40 | expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; | |
41 | else | |
42 | expected_opsize = TCPOLEN_MPTCP_MPC_SYN; | |
43 | } | |
44 | if (opsize != expected_opsize) | |
eda7acdd PK |
45 | break; |
46 | ||
cc7972ea | 47 | /* try to be gentle vs future versions on the initial syn */ |
eda7acdd | 48 | version = *ptr++ & MPTCP_VERSION_MASK; |
cc7972ea CP |
49 | if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
50 | if (version != MPTCP_SUPPORTED_VERSION) | |
51 | break; | |
52 | } else if (version < MPTCP_SUPPORTED_VERSION) { | |
eda7acdd | 53 | break; |
cc7972ea | 54 | } |
eda7acdd PK |
55 | |
56 | flags = *ptr++; | |
65492c5a | 57 | if (!mptcp_cap_flag_sha256(flags) || |
eda7acdd PK |
58 | (flags & MPTCP_CAP_EXTENSIBILITY)) |
59 | break; | |
60 | ||
61 | /* RFC 6824, Section 3.1: | |
62 | * "For the Checksum Required bit (labeled "A"), if either | |
63 | * host requires the use of checksums, checksums MUST be used. | |
64 | * In other words, the only way for checksums not to be used | |
65 | * is if both hosts in their SYNs set A=0." | |
66 | * | |
67 | * Section 3.3.0: | |
68 | * "If a checksum is not present when its use has been | |
69 | * negotiated, the receiver MUST close the subflow with a RST as | |
70 | * it is considered broken." | |
71 | * | |
72 | * We don't implement DSS checksum - fall back to TCP. | |
73 | */ | |
74 | if (flags & MPTCP_CAP_CHECKSUM_REQD) | |
75 | break; | |
76 | ||
77 | mp_opt->mp_capable = 1; | |
cc7972ea CP |
78 | if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
79 | mp_opt->sndr_key = get_unaligned_be64(ptr); | |
80 | ptr += 8; | |
81 | } | |
82 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { | |
eda7acdd PK |
83 | mp_opt->rcvr_key = get_unaligned_be64(ptr); |
84 | ptr += 8; | |
eda7acdd | 85 | } |
cc7972ea CP |
86 | if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) { |
87 | /* Section 3.1.: | |
88 | * "the data parameters in a MP_CAPABLE are semantically | |
89 | * equivalent to those in a DSS option and can be used | |
90 | * interchangeably." | |
91 | */ | |
92 | mp_opt->dss = 1; | |
93 | mp_opt->use_map = 1; | |
94 | mp_opt->mpc_map = 1; | |
95 | mp_opt->data_len = get_unaligned_be16(ptr); | |
96 | ptr += 2; | |
97 | } | |
98 | pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d", | |
99 | version, flags, opsize, mp_opt->sndr_key, | |
100 | mp_opt->rcvr_key, mp_opt->data_len); | |
eda7acdd PK |
101 | break; |
102 | ||
f296234c PK |
103 | case MPTCPOPT_MP_JOIN: |
104 | mp_opt->mp_join = 1; | |
105 | if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { | |
106 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; | |
107 | mp_opt->join_id = *ptr++; | |
108 | mp_opt->token = get_unaligned_be32(ptr); | |
109 | ptr += 4; | |
110 | mp_opt->nonce = get_unaligned_be32(ptr); | |
111 | ptr += 4; | |
112 | pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", | |
113 | mp_opt->backup, mp_opt->join_id, | |
114 | mp_opt->token, mp_opt->nonce); | |
115 | } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { | |
116 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; | |
117 | mp_opt->join_id = *ptr++; | |
118 | mp_opt->thmac = get_unaligned_be64(ptr); | |
119 | ptr += 8; | |
120 | mp_opt->nonce = get_unaligned_be32(ptr); | |
121 | ptr += 4; | |
122 | pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", | |
123 | mp_opt->backup, mp_opt->join_id, | |
124 | mp_opt->thmac, mp_opt->nonce); | |
125 | } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { | |
126 | ptr += 2; | |
127 | memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); | |
128 | pr_debug("MP_JOIN hmac"); | |
129 | } else { | |
130 | pr_warn("MP_JOIN bad option size"); | |
131 | mp_opt->mp_join = 0; | |
132 | } | |
133 | break; | |
134 | ||
eda7acdd PK |
135 | case MPTCPOPT_DSS: |
136 | pr_debug("DSS"); | |
648ef4b8 MM |
137 | ptr++; |
138 | ||
cc7972ea CP |
139 | /* we must clear 'mpc_map' be able to detect MP_CAPABLE |
140 | * map vs DSS map in mptcp_incoming_options(), and reconstruct | |
141 | * map info accordingly | |
142 | */ | |
143 | mp_opt->mpc_map = 0; | |
648ef4b8 MM |
144 | flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
145 | mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; | |
146 | mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; | |
147 | mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; | |
148 | mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; | |
149 | mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); | |
150 | ||
151 | pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", | |
152 | mp_opt->data_fin, mp_opt->dsn64, | |
153 | mp_opt->use_map, mp_opt->ack64, | |
154 | mp_opt->use_ack); | |
155 | ||
156 | expected_opsize = TCPOLEN_MPTCP_DSS_BASE; | |
157 | ||
158 | if (mp_opt->use_ack) { | |
159 | if (mp_opt->ack64) | |
160 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; | |
161 | else | |
162 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; | |
163 | } | |
164 | ||
165 | if (mp_opt->use_map) { | |
166 | if (mp_opt->dsn64) | |
167 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; | |
168 | else | |
169 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; | |
170 | } | |
171 | ||
172 | /* RFC 6824, Section 3.3: | |
173 | * If a checksum is present, but its use had | |
174 | * not been negotiated in the MP_CAPABLE handshake, | |
175 | * the checksum field MUST be ignored. | |
176 | */ | |
177 | if (opsize != expected_opsize && | |
178 | opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) | |
179 | break; | |
180 | ||
eda7acdd | 181 | mp_opt->dss = 1; |
648ef4b8 MM |
182 | |
183 | if (mp_opt->use_ack) { | |
184 | if (mp_opt->ack64) { | |
185 | mp_opt->data_ack = get_unaligned_be64(ptr); | |
186 | ptr += 8; | |
187 | } else { | |
188 | mp_opt->data_ack = get_unaligned_be32(ptr); | |
189 | ptr += 4; | |
190 | } | |
191 | ||
192 | pr_debug("data_ack=%llu", mp_opt->data_ack); | |
193 | } | |
194 | ||
195 | if (mp_opt->use_map) { | |
196 | if (mp_opt->dsn64) { | |
197 | mp_opt->data_seq = get_unaligned_be64(ptr); | |
198 | ptr += 8; | |
199 | } else { | |
200 | mp_opt->data_seq = get_unaligned_be32(ptr); | |
201 | ptr += 4; | |
202 | } | |
203 | ||
204 | mp_opt->subflow_seq = get_unaligned_be32(ptr); | |
205 | ptr += 4; | |
206 | ||
207 | mp_opt->data_len = get_unaligned_be16(ptr); | |
208 | ptr += 2; | |
209 | ||
210 | pr_debug("data_seq=%llu subflow_seq=%u data_len=%u", | |
211 | mp_opt->data_seq, mp_opt->subflow_seq, | |
212 | mp_opt->data_len); | |
213 | } | |
214 | ||
eda7acdd PK |
215 | break; |
216 | ||
3df523ab PK |
217 | case MPTCPOPT_ADD_ADDR: |
218 | mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; | |
219 | if (!mp_opt->echo) { | |
220 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR || | |
221 | opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) | |
222 | mp_opt->family = MPTCP_ADDR_IPVERSION_4; | |
223 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
224 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || | |
225 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) | |
226 | mp_opt->family = MPTCP_ADDR_IPVERSION_6; | |
227 | #endif | |
228 | else | |
229 | break; | |
230 | } else { | |
231 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || | |
232 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) | |
233 | mp_opt->family = MPTCP_ADDR_IPVERSION_4; | |
234 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
235 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || | |
236 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) | |
237 | mp_opt->family = MPTCP_ADDR_IPVERSION_6; | |
238 | #endif | |
239 | else | |
240 | break; | |
241 | } | |
242 | ||
243 | mp_opt->add_addr = 1; | |
3df523ab | 244 | mp_opt->addr_id = *ptr++; |
3df523ab PK |
245 | if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) { |
246 | memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4); | |
247 | ptr += 4; | |
248 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || | |
249 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { | |
250 | mp_opt->port = get_unaligned_be16(ptr); | |
251 | ptr += 2; | |
252 | } | |
253 | } | |
254 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
255 | else { | |
256 | memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16); | |
257 | ptr += 16; | |
258 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || | |
259 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { | |
260 | mp_opt->port = get_unaligned_be16(ptr); | |
261 | ptr += 2; | |
262 | } | |
263 | } | |
264 | #endif | |
265 | if (!mp_opt->echo) { | |
266 | mp_opt->ahmac = get_unaligned_be64(ptr); | |
267 | ptr += 8; | |
268 | } | |
90a4aea8 GT |
269 | pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", |
270 | (mp_opt->family == MPTCP_ADDR_IPVERSION_6) ? "6" : "", | |
271 | mp_opt->addr_id, mp_opt->ahmac, mp_opt->echo, mp_opt->port); | |
3df523ab PK |
272 | break; |
273 | ||
274 | case MPTCPOPT_RM_ADDR: | |
275 | if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE) | |
276 | break; | |
277 | ||
8e60eed6 GT |
278 | ptr++; |
279 | ||
3df523ab PK |
280 | mp_opt->rm_addr = 1; |
281 | mp_opt->rm_id = *ptr++; | |
282 | pr_debug("RM_ADDR: id=%d", mp_opt->rm_id); | |
283 | break; | |
284 | ||
50c504a2 FW |
285 | case MPTCPOPT_MP_FASTCLOSE: |
286 | if (opsize != TCPOLEN_MPTCP_FASTCLOSE) | |
287 | break; | |
288 | ||
289 | ptr += 2; | |
290 | mp_opt->rcvr_key = get_unaligned_be64(ptr); | |
291 | ptr += 8; | |
292 | mp_opt->fastclose = 1; | |
293 | break; | |
294 | ||
eda7acdd PK |
295 | default: |
296 | break; | |
297 | } | |
298 | } | |
299 | ||
cec37a6e | 300 | void mptcp_get_options(const struct sk_buff *skb, |
cfde141e | 301 | struct mptcp_options_received *mp_opt) |
cec37a6e | 302 | { |
cec37a6e | 303 | const struct tcphdr *th = tcp_hdr(skb); |
cfde141e PA |
304 | const unsigned char *ptr; |
305 | int length; | |
cec37a6e | 306 | |
cfde141e PA |
307 | /* initialize option status */ |
308 | mp_opt->mp_capable = 0; | |
309 | mp_opt->mp_join = 0; | |
310 | mp_opt->add_addr = 0; | |
fe2d9b1a | 311 | mp_opt->ahmac = 0; |
50c504a2 | 312 | mp_opt->fastclose = 0; |
65b8c8a6 | 313 | mp_opt->port = 0; |
cfde141e PA |
314 | mp_opt->rm_addr = 0; |
315 | mp_opt->dss = 0; | |
316 | ||
317 | length = (th->doff * 4) - sizeof(struct tcphdr); | |
cec37a6e PK |
318 | ptr = (const unsigned char *)(th + 1); |
319 | ||
320 | while (length > 0) { | |
321 | int opcode = *ptr++; | |
322 | int opsize; | |
323 | ||
324 | switch (opcode) { | |
325 | case TCPOPT_EOL: | |
326 | return; | |
327 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
328 | length--; | |
329 | continue; | |
330 | default: | |
331 | opsize = *ptr++; | |
332 | if (opsize < 2) /* "silly options" */ | |
333 | return; | |
334 | if (opsize > length) | |
335 | return; /* don't parse partial options */ | |
336 | if (opcode == TCPOPT_MPTCP) | |
cfde141e | 337 | mptcp_parse_option(skb, ptr, opsize, mp_opt); |
cec37a6e PK |
338 | ptr += opsize - 2; |
339 | length -= opsize; | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
cc7972ea CP |
344 | bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
345 | unsigned int *size, struct mptcp_out_options *opts) | |
cec37a6e PK |
346 | { |
347 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
348 | ||
cc7972ea CP |
349 | /* we will use snd_isn to detect first pkt [re]transmission |
350 | * in mptcp_established_options_mp() | |
351 | */ | |
352 | subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; | |
cec37a6e | 353 | if (subflow->request_mptcp) { |
cec37a6e | 354 | opts->suboptions = OPTION_MPTCP_MPC_SYN; |
cec37a6e PK |
355 | *size = TCPOLEN_MPTCP_MPC_SYN; |
356 | return true; | |
ec3edaa7 PK |
357 | } else if (subflow->request_join) { |
358 | pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, | |
359 | subflow->local_nonce); | |
360 | opts->suboptions = OPTION_MPTCP_MPJ_SYN; | |
361 | opts->join_id = subflow->local_id; | |
362 | opts->token = subflow->remote_token; | |
363 | opts->nonce = subflow->local_nonce; | |
364 | opts->backup = subflow->request_bkup; | |
365 | *size = TCPOLEN_MPTCP_MPJ_SYN; | |
366 | return true; | |
cec37a6e PK |
367 | } |
368 | return false; | |
369 | } | |
370 | ||
ec3edaa7 PK |
371 | /* MP_JOIN client subflow must wait for 4th ack before sending any data: |
372 | * TCP can't schedule delack timer before the subflow is fully established. | |
373 | * MPTCP uses the delack timer to do 3rd ack retransmissions | |
374 | */ | |
375 | static void schedule_3rdack_retransmission(struct sock *sk) | |
376 | { | |
377 | struct inet_connection_sock *icsk = inet_csk(sk); | |
378 | struct tcp_sock *tp = tcp_sk(sk); | |
379 | unsigned long timeout; | |
380 | ||
381 | /* reschedule with a timeout above RTT, as we must look only for drop */ | |
382 | if (tp->srtt_us) | |
383 | timeout = tp->srtt_us << 1; | |
384 | else | |
385 | timeout = TCP_TIMEOUT_INIT; | |
386 | ||
387 | WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); | |
388 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
389 | icsk->icsk_ack.timeout = timeout; | |
390 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
391 | } | |
392 | ||
393 | static void clear_3rdack_retransmission(struct sock *sk) | |
394 | { | |
395 | struct inet_connection_sock *icsk = inet_csk(sk); | |
396 | ||
397 | sk_stop_timer(sk, &icsk->icsk_delack_timer); | |
398 | icsk->icsk_ack.timeout = 0; | |
399 | icsk->icsk_ack.ato = 0; | |
400 | icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); | |
401 | } | |
402 | ||
cc7972ea CP |
403 | static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
404 | unsigned int *size, | |
6d0060f6 MM |
405 | unsigned int remaining, |
406 | struct mptcp_out_options *opts) | |
cec37a6e PK |
407 | { |
408 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
cc7972ea CP |
409 | struct mptcp_ext *mpext; |
410 | unsigned int data_len; | |
411 | ||
ec3edaa7 PK |
412 | /* When skb is not available, we better over-estimate the emitted |
413 | * options len. A full DSS option (28 bytes) is longer than | |
414 | * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so | |
415 | * tell the caller to defer the estimate to | |
416 | * mptcp_established_options_dss(), which will reserve enough space. | |
417 | */ | |
418 | if (!skb) | |
419 | return false; | |
cc7972ea | 420 | |
ec3edaa7 PK |
421 | /* MPC/MPJ needed only on 3rd ack packet */ |
422 | if (subflow->fully_established || | |
423 | subflow->snd_isn != TCP_SKB_CB(skb)->seq) | |
424 | return false; | |
425 | ||
426 | if (subflow->mp_capable) { | |
cc7972ea CP |
427 | mpext = mptcp_get_ext(skb); |
428 | data_len = mpext ? mpext->data_len : 0; | |
cec37a6e | 429 | |
cc7972ea CP |
430 | /* we will check ext_copy.data_len in mptcp_write_options() to |
431 | * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and | |
432 | * TCPOLEN_MPTCP_MPC_ACK | |
433 | */ | |
434 | opts->ext_copy.data_len = data_len; | |
cec37a6e PK |
435 | opts->suboptions = OPTION_MPTCP_MPC_ACK; |
436 | opts->sndr_key = subflow->local_key; | |
437 | opts->rcvr_key = subflow->remote_key; | |
cc7972ea CP |
438 | |
439 | /* Section 3.1. | |
440 | * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK | |
441 | * packets that start the first subflow of an MPTCP connection, | |
442 | * as well as the first packet that carries data | |
443 | */ | |
444 | if (data_len > 0) | |
445 | *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); | |
446 | else | |
447 | *size = TCPOLEN_MPTCP_MPC_ACK; | |
448 | ||
449 | pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", | |
450 | subflow, subflow->local_key, subflow->remote_key, | |
451 | data_len); | |
452 | ||
cec37a6e | 453 | return true; |
ec3edaa7 PK |
454 | } else if (subflow->mp_join) { |
455 | opts->suboptions = OPTION_MPTCP_MPJ_ACK; | |
456 | memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); | |
457 | *size = TCPOLEN_MPTCP_MPJ_ACK; | |
458 | pr_debug("subflow=%p", subflow); | |
459 | ||
460 | schedule_3rdack_retransmission(sk); | |
461 | return true; | |
cec37a6e PK |
462 | } |
463 | return false; | |
464 | } | |
465 | ||
6d0060f6 | 466 | static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
9c29e361 | 467 | struct sk_buff *skb, struct mptcp_ext *ext) |
6d0060f6 | 468 | { |
017512a0 PA |
469 | /* The write_seq value has already been incremented, so the actual |
470 | * sequence number for the DATA_FIN is one less. | |
471 | */ | |
472 | u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; | |
7279da61 | 473 | |
9c29e361 | 474 | if (!ext->use_map || !skb->len) { |
6d0060f6 MM |
475 | /* RFC6824 requires a DSS mapping with specific values |
476 | * if DATA_FIN is set but no data payload is mapped | |
477 | */ | |
6d37a0b8 | 478 | ext->data_fin = 1; |
6d0060f6 MM |
479 | ext->use_map = 1; |
480 | ext->dsn64 = 1; | |
017512a0 | 481 | ext->data_seq = data_fin_tx_seq; |
6d0060f6 MM |
482 | ext->subflow_seq = 0; |
483 | ext->data_len = 1; | |
7279da61 | 484 | } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { |
6d37a0b8 MM |
485 | /* If there's an existing DSS mapping and it is the |
486 | * final mapping, DATA_FIN consumes 1 additional byte of | |
487 | * mapping space. | |
6d0060f6 | 488 | */ |
6d37a0b8 | 489 | ext->data_fin = 1; |
6d0060f6 MM |
490 | ext->data_len++; |
491 | } | |
492 | } | |
493 | ||
494 | static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, | |
495 | unsigned int *size, | |
496 | unsigned int remaining, | |
497 | struct mptcp_out_options *opts) | |
498 | { | |
499 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
7279da61 | 500 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
e3859603 | 501 | u64 snd_data_fin_enable, ack_seq; |
6d0060f6 MM |
502 | unsigned int dss_size = 0; |
503 | struct mptcp_ext *mpext; | |
6d0060f6 | 504 | unsigned int ack_size; |
d22f4988 | 505 | bool ret = false; |
6d0060f6 | 506 | |
0bac966a | 507 | mpext = skb ? mptcp_get_ext(skb) : NULL; |
e16163b6 | 508 | snd_data_fin_enable = mptcp_data_fin_enabled(msk); |
6d0060f6 | 509 | |
7279da61 | 510 | if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { |
6d0060f6 MM |
511 | unsigned int map_size; |
512 | ||
513 | map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; | |
514 | ||
515 | remaining -= map_size; | |
516 | dss_size = map_size; | |
517 | if (mpext) | |
518 | opts->ext_copy = *mpext; | |
519 | ||
7279da61 | 520 | if (skb && snd_data_fin_enable) |
9c29e361 | 521 | mptcp_write_data_fin(subflow, skb, &opts->ext_copy); |
d22f4988 CP |
522 | ret = true; |
523 | } | |
524 | ||
2398e399 PA |
525 | /* passive sockets msk will set the 'can_ack' after accept(), even |
526 | * if the first subflow may have the already the remote key handy | |
527 | */ | |
d22f4988 | 528 | opts->ext_copy.use_ack = 0; |
dc093db5 | 529 | if (!READ_ONCE(msk->can_ack)) { |
d22f4988 CP |
530 | *size = ALIGN(dss_size, 4); |
531 | return ret; | |
6d0060f6 MM |
532 | } |
533 | ||
e3859603 | 534 | ack_seq = READ_ONCE(msk->ack_seq); |
37198e93 | 535 | if (READ_ONCE(msk->use_64bit_ack)) { |
a0c1d0ea | 536 | ack_size = TCPOLEN_MPTCP_DSS_ACK64; |
e3859603 | 537 | opts->ext_copy.data_ack = ack_seq; |
a0c1d0ea CP |
538 | opts->ext_copy.ack64 = 1; |
539 | } else { | |
540 | ack_size = TCPOLEN_MPTCP_DSS_ACK32; | |
e3859603 | 541 | opts->ext_copy.data_ack32 = (uint32_t)ack_seq; |
a0c1d0ea CP |
542 | opts->ext_copy.ack64 = 0; |
543 | } | |
544 | opts->ext_copy.use_ack = 1; | |
ea4ca586 | 545 | WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); |
6d0060f6 MM |
546 | |
547 | /* Add kind/length/subtype/flag overhead if mapping is not populated */ | |
548 | if (dss_size == 0) | |
549 | ack_size += TCPOLEN_MPTCP_DSS_BASE; | |
550 | ||
551 | dss_size += ack_size; | |
552 | ||
6d0060f6 MM |
553 | *size = ALIGN(dss_size, 4); |
554 | return true; | |
555 | } | |
556 | ||
3df523ab PK |
557 | static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id, |
558 | struct in_addr *addr) | |
559 | { | |
bd697222 | 560 | u8 hmac[SHA256_DIGEST_SIZE]; |
3df523ab PK |
561 | u8 msg[7]; |
562 | ||
563 | msg[0] = addr_id; | |
564 | memcpy(&msg[1], &addr->s_addr, 4); | |
565 | msg[5] = 0; | |
566 | msg[6] = 0; | |
567 | ||
568 | mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac); | |
569 | ||
bd697222 | 570 | return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
3df523ab PK |
571 | } |
572 | ||
573 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
574 | static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id, | |
575 | struct in6_addr *addr) | |
576 | { | |
bd697222 | 577 | u8 hmac[SHA256_DIGEST_SIZE]; |
3df523ab PK |
578 | u8 msg[19]; |
579 | ||
580 | msg[0] = addr_id; | |
581 | memcpy(&msg[1], &addr->s6_addr, 16); | |
582 | msg[17] = 0; | |
583 | msg[18] = 0; | |
584 | ||
585 | mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac); | |
586 | ||
bd697222 | 587 | return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
3df523ab PK |
588 | } |
589 | #endif | |
590 | ||
84dfe367 | 591 | static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, |
f643b803 GT |
592 | unsigned int *size, |
593 | unsigned int remaining, | |
594 | struct mptcp_out_options *opts) | |
3df523ab PK |
595 | { |
596 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
597 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
84dfe367 GT |
598 | bool drop_other_suboptions = false; |
599 | unsigned int opt_size = *size; | |
1b1c7a0e | 600 | struct mptcp_addr_info saddr; |
6a6c05a8 | 601 | bool echo; |
4a2777a8 | 602 | bool port; |
1b1c7a0e | 603 | int len; |
3df523ab | 604 | |
fbe0f87a GT |
605 | if ((mptcp_pm_should_add_signal_ipv6(msk) || |
606 | mptcp_pm_should_add_signal_port(msk)) && | |
84dfe367 GT |
607 | skb && skb_is_tcp_pure_ack(skb)) { |
608 | pr_debug("drop other suboptions"); | |
609 | opts->suboptions = 0; | |
3ae32c07 GT |
610 | opts->ext_copy.use_ack = 0; |
611 | opts->ext_copy.use_map = 0; | |
84dfe367 GT |
612 | remaining += opt_size; |
613 | drop_other_suboptions = true; | |
614 | } | |
615 | ||
f643b803 | 616 | if (!mptcp_pm_should_add_signal(msk) || |
4a2777a8 | 617 | !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port))) |
1b1c7a0e PK |
618 | return false; |
619 | ||
4a2777a8 | 620 | len = mptcp_add_addr_len(saddr.family, echo, port); |
1b1c7a0e PK |
621 | if (remaining < len) |
622 | return false; | |
3df523ab | 623 | |
1b1c7a0e | 624 | *size = len; |
84dfe367 GT |
625 | if (drop_other_suboptions) |
626 | *size -= opt_size; | |
1b1c7a0e | 627 | opts->addr_id = saddr.id; |
4a2777a8 GT |
628 | if (port) |
629 | opts->port = ntohs(saddr.port); | |
1b1c7a0e | 630 | if (saddr.family == AF_INET) { |
3df523ab | 631 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR; |
1b1c7a0e | 632 | opts->addr = saddr.addr; |
6a6c05a8 GT |
633 | if (!echo) { |
634 | opts->ahmac = add_addr_generate_hmac(msk->local_key, | |
635 | msk->remote_key, | |
636 | opts->addr_id, | |
637 | &opts->addr); | |
638 | } | |
3df523ab PK |
639 | } |
640 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1b1c7a0e | 641 | else if (saddr.family == AF_INET6) { |
3df523ab | 642 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR6; |
1b1c7a0e | 643 | opts->addr6 = saddr.addr6; |
6a6c05a8 GT |
644 | if (!echo) { |
645 | opts->ahmac = add_addr6_generate_hmac(msk->local_key, | |
646 | msk->remote_key, | |
647 | opts->addr_id, | |
648 | &opts->addr6); | |
649 | } | |
3df523ab PK |
650 | } |
651 | #endif | |
4a2777a8 GT |
652 | pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", |
653 | opts->addr_id, opts->ahmac, echo, opts->port); | |
3df523ab PK |
654 | |
655 | return true; | |
656 | } | |
657 | ||
5cb104ae GT |
658 | static bool mptcp_established_options_rm_addr(struct sock *sk, |
659 | unsigned int *size, | |
660 | unsigned int remaining, | |
661 | struct mptcp_out_options *opts) | |
662 | { | |
663 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
664 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); | |
665 | u8 rm_id; | |
666 | ||
667 | if (!mptcp_pm_should_rm_signal(msk) || | |
668 | !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id))) | |
669 | return false; | |
670 | ||
671 | if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE) | |
672 | return false; | |
673 | ||
674 | *size = TCPOLEN_MPTCP_RM_ADDR_BASE; | |
675 | opts->suboptions |= OPTION_MPTCP_RM_ADDR; | |
676 | opts->rm_id = rm_id; | |
677 | ||
678 | pr_debug("rm_id=%d", opts->rm_id); | |
679 | ||
680 | return true; | |
681 | } | |
682 | ||
6d0060f6 MM |
683 | bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, |
684 | unsigned int *size, unsigned int remaining, | |
685 | struct mptcp_out_options *opts) | |
686 | { | |
687 | unsigned int opt_size = 0; | |
688 | bool ret = false; | |
689 | ||
3df523ab PK |
690 | opts->suboptions = 0; |
691 | ||
e1ff9e82 DC |
692 | if (unlikely(mptcp_check_fallback(sk))) |
693 | return false; | |
694 | ||
d5824847 PA |
695 | /* prevent adding of any MPTCP related options on reset packet |
696 | * until we support MP_TCPRST/MP_FASTCLOSE | |
697 | */ | |
698 | if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) | |
699 | return false; | |
700 | ||
cc7972ea | 701 | if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts)) |
6d0060f6 MM |
702 | ret = true; |
703 | else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining, | |
704 | opts)) | |
705 | ret = true; | |
706 | ||
707 | /* we reserved enough space for the above options, and exceeding the | |
708 | * TCP option space would be fatal | |
709 | */ | |
710 | if (WARN_ON_ONCE(opt_size > remaining)) | |
711 | return false; | |
712 | ||
713 | *size += opt_size; | |
714 | remaining -= opt_size; | |
84dfe367 | 715 | if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { |
3df523ab PK |
716 | *size += opt_size; |
717 | remaining -= opt_size; | |
718 | ret = true; | |
5cb104ae GT |
719 | } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { |
720 | *size += opt_size; | |
721 | remaining -= opt_size; | |
722 | ret = true; | |
3df523ab | 723 | } |
6d0060f6 MM |
724 | |
725 | return ret; | |
726 | } | |
727 | ||
cec37a6e PK |
728 | bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
729 | struct mptcp_out_options *opts) | |
730 | { | |
731 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
732 | ||
733 | if (subflow_req->mp_capable) { | |
734 | opts->suboptions = OPTION_MPTCP_MPC_SYNACK; | |
735 | opts->sndr_key = subflow_req->local_key; | |
736 | *size = TCPOLEN_MPTCP_MPC_SYNACK; | |
737 | pr_debug("subflow_req=%p, local_key=%llu", | |
738 | subflow_req, subflow_req->local_key); | |
739 | return true; | |
f296234c PK |
740 | } else if (subflow_req->mp_join) { |
741 | opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; | |
742 | opts->backup = subflow_req->backup; | |
743 | opts->join_id = subflow_req->local_id; | |
744 | opts->thmac = subflow_req->thmac; | |
745 | opts->nonce = subflow_req->local_nonce; | |
746 | pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", | |
747 | subflow_req, opts->backup, opts->join_id, | |
748 | opts->thmac, opts->nonce); | |
749 | *size = TCPOLEN_MPTCP_MPJ_SYNACK; | |
750 | return true; | |
cec37a6e PK |
751 | } |
752 | return false; | |
753 | } | |
754 | ||
d5824847 | 755 | static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, |
f296234c | 756 | struct mptcp_subflow_context *subflow, |
0be534f5 PA |
757 | struct sk_buff *skb, |
758 | struct mptcp_options_received *mp_opt) | |
d22f4988 CP |
759 | { |
760 | /* here we can process OoO, in-window pkts, only in-sequence 4th ack | |
f296234c | 761 | * will make the subflow fully established |
d22f4988 | 762 | */ |
f296234c PK |
763 | if (likely(subflow->fully_established)) { |
764 | /* on passive sockets, check for 3rd ack retransmission | |
765 | * note that msk is always set by subflow_syn_recv_sock() | |
766 | * for mp_join subflows | |
767 | */ | |
768 | if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && | |
769 | TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && | |
770 | subflow->mp_join && mp_opt->mp_join && | |
771 | READ_ONCE(msk->pm.server_side)) | |
d5824847 | 772 | tcp_send_ack(ssk); |
f296234c PK |
773 | goto fully_established; |
774 | } | |
775 | ||
d5824847 PA |
776 | /* we must process OoO packets before the first subflow is fully |
777 | * established. OoO packets are instead a protocol violation | |
778 | * for MP_JOIN subflows as the peer must not send any data | |
779 | * before receiving the forth ack - cfr. RFC 8684 section 3.2. | |
f296234c | 780 | */ |
d5824847 PA |
781 | if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { |
782 | if (subflow->mp_join) | |
783 | goto reset; | |
f296234c | 784 | return subflow->mp_capable; |
d5824847 | 785 | } |
d22f4988 | 786 | |
5a91e32b | 787 | if (mp_opt->dss && mp_opt->use_ack) { |
f296234c PK |
788 | /* subflows are fully established as soon as we get any |
789 | * additional ack. | |
790 | */ | |
0be534f5 | 791 | subflow->fully_established = 1; |
b93df08c | 792 | WRITE_ONCE(msk->fully_established, true); |
f296234c PK |
793 | goto fully_established; |
794 | } | |
d22f4988 | 795 | |
84dfe367 GT |
796 | if (mp_opt->add_addr) { |
797 | WRITE_ONCE(msk->fully_established, true); | |
798 | return true; | |
799 | } | |
800 | ||
d22f4988 | 801 | /* If the first established packet does not contain MP_CAPABLE + data |
d5824847 PA |
802 | * then fallback to TCP. Fallback scenarios requires a reset for |
803 | * MP_JOIN subflows. | |
d22f4988 CP |
804 | */ |
805 | if (!mp_opt->mp_capable) { | |
d5824847 PA |
806 | if (subflow->mp_join) |
807 | goto reset; | |
d22f4988 | 808 | subflow->mp_capable = 0; |
e1ff9e82 DC |
809 | pr_fallback(msk); |
810 | __mptcp_do_fallback(msk); | |
d22f4988 CP |
811 | return false; |
812 | } | |
f296234c | 813 | |
d6085fe1 PA |
814 | if (unlikely(!READ_ONCE(msk->pm.server_side))) |
815 | pr_warn_once("bogus mpc option on established client sk"); | |
b93df08c | 816 | mptcp_subflow_fully_established(subflow, mp_opt); |
f296234c PK |
817 | |
818 | fully_established: | |
5b950ff4 PA |
819 | /* if the subflow is not already linked into the conn_list, we can't |
820 | * notify the PM: this subflow is still on the listener queue | |
821 | * and the PM possibly acquiring the subflow lock could race with | |
822 | * the listener close | |
823 | */ | |
824 | if (likely(subflow->pm_notified) || list_empty(&subflow->node)) | |
f296234c PK |
825 | return true; |
826 | ||
827 | subflow->pm_notified = 1; | |
ec3edaa7 | 828 | if (subflow->mp_join) { |
d5824847 | 829 | clear_3rdack_retransmission(ssk); |
f296234c | 830 | mptcp_pm_subflow_established(msk, subflow); |
ec3edaa7 | 831 | } else { |
f296234c | 832 | mptcp_pm_fully_established(msk); |
ec3edaa7 | 833 | } |
d22f4988 | 834 | return true; |
d5824847 PA |
835 | |
836 | reset: | |
837 | mptcp_subflow_reset(ssk); | |
838 | return false; | |
d22f4988 CP |
839 | } |
840 | ||
cc9d2566 PA |
841 | static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) |
842 | { | |
843 | u32 old_ack32, cur_ack32; | |
844 | ||
845 | if (use_64bit) | |
846 | return cur_ack; | |
847 | ||
848 | old_ack32 = (u32)old_ack; | |
849 | cur_ack32 = (u32)cur_ack; | |
850 | cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; | |
851 | if (unlikely(before(cur_ack32, old_ack32))) | |
852 | return cur_ack + (1LL << 32); | |
853 | return cur_ack; | |
854 | } | |
855 | ||
6f8a612a | 856 | static void ack_update_msk(struct mptcp_sock *msk, |
6e628cd3 | 857 | struct sock *ssk, |
6f8a612a | 858 | struct mptcp_options_received *mp_opt) |
cc9d2566 | 859 | { |
7439d687 | 860 | u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); |
6f8a612a | 861 | struct sock *sk = (struct sock *)msk; |
7439d687 PA |
862 | u64 old_snd_una; |
863 | ||
864 | mptcp_data_lock(sk); | |
cc9d2566 PA |
865 | |
866 | /* avoid ack expansion on update conflict, to reduce the risk of | |
867 | * wrongly expanding to a future ack sequence number, which is way | |
868 | * more dangerous than missing an ack | |
869 | */ | |
7439d687 | 870 | old_snd_una = msk->snd_una; |
cc9d2566 PA |
871 | new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); |
872 | ||
873 | /* ACK for data not even sent yet? Ignore. */ | |
eaa2ffab | 874 | if (after64(new_snd_una, snd_nxt)) |
cc9d2566 PA |
875 | new_snd_una = old_snd_una; |
876 | ||
6f8a612a FW |
877 | new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; |
878 | ||
219d0499 | 879 | if (after64(new_wnd_end, msk->wnd_end)) |
7439d687 | 880 | msk->wnd_end = new_wnd_end; |
219d0499 PA |
881 | |
882 | /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ | |
883 | if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)) && | |
884 | sk_stream_memory_free(ssk)) | |
885 | __mptcp_check_push(sk, ssk); | |
6f8a612a | 886 | |
7439d687 PA |
887 | if (after64(new_snd_una, old_snd_una)) { |
888 | msk->snd_una = new_snd_una; | |
889 | __mptcp_data_acked(sk); | |
cc9d2566 | 890 | } |
7439d687 | 891 | mptcp_data_unlock(sk); |
cc9d2566 PA |
892 | } |
893 | ||
1a49b2c2 | 894 | bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) |
3721b9b6 MM |
895 | { |
896 | /* Skip if DATA_FIN was already received. | |
897 | * If updating simultaneously with the recvmsg loop, values | |
898 | * should match. If they mismatch, the peer is misbehaving and | |
899 | * we will prefer the most recent information. | |
900 | */ | |
901 | if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first)) | |
902 | return false; | |
903 | ||
1a49b2c2 MM |
904 | WRITE_ONCE(msk->rcv_data_fin_seq, |
905 | expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); | |
3721b9b6 MM |
906 | WRITE_ONCE(msk->rcv_data_fin, 1); |
907 | ||
908 | return true; | |
909 | } | |
910 | ||
1b1c7a0e PK |
911 | static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
912 | struct mptcp_options_received *mp_opt) | |
913 | { | |
914 | u64 hmac = 0; | |
915 | ||
916 | if (mp_opt->echo) | |
917 | return true; | |
918 | ||
919 | if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) | |
920 | hmac = add_addr_generate_hmac(msk->remote_key, | |
921 | msk->local_key, | |
922 | mp_opt->addr_id, &mp_opt->addr); | |
923 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
924 | else | |
925 | hmac = add_addr6_generate_hmac(msk->remote_key, | |
926 | msk->local_key, | |
927 | mp_opt->addr_id, &mp_opt->addr6); | |
928 | #endif | |
929 | ||
930 | pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", | |
931 | msk, (unsigned long long)hmac, | |
932 | (unsigned long long)mp_opt->ahmac); | |
933 | ||
934 | return hmac == mp_opt->ahmac; | |
935 | } | |
936 | ||
77d0cab9 | 937 | void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) |
648ef4b8 | 938 | { |
d22f4988 | 939 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
1b1c7a0e | 940 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
cfde141e | 941 | struct mptcp_options_received mp_opt; |
648ef4b8 MM |
942 | struct mptcp_ext *mpext; |
943 | ||
6e628cd3 PA |
944 | if (__mptcp_check_fallback(msk)) { |
945 | /* Keep it simple and unconditionally trigger send data cleanup and | |
946 | * pending queue spooling. We will need to acquire the data lock | |
947 | * for more accurate checks, and once the lock is acquired, such | |
948 | * helpers are cheap. | |
949 | */ | |
950 | mptcp_data_lock(subflow->conn); | |
219d0499 PA |
951 | if (sk_stream_memory_free(sk)) |
952 | __mptcp_check_push(subflow->conn, sk); | |
6e628cd3 PA |
953 | __mptcp_data_acked(subflow->conn); |
954 | mptcp_data_unlock(subflow->conn); | |
e1ff9e82 | 955 | return; |
6e628cd3 | 956 | } |
e1ff9e82 | 957 | |
cfde141e PA |
958 | mptcp_get_options(skb, &mp_opt); |
959 | if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) | |
d22f4988 | 960 | return; |
648ef4b8 | 961 | |
50c504a2 FW |
962 | if (mp_opt.fastclose && |
963 | msk->local_key == mp_opt.rcvr_key) { | |
964 | WRITE_ONCE(msk->rcv_fastclose, true); | |
965 | mptcp_schedule_work((struct sock *)msk); | |
966 | } | |
967 | ||
cfde141e | 968 | if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { |
1b1c7a0e PK |
969 | struct mptcp_addr_info addr; |
970 | ||
cfde141e PA |
971 | addr.port = htons(mp_opt.port); |
972 | addr.id = mp_opt.addr_id; | |
973 | if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) { | |
1b1c7a0e | 974 | addr.family = AF_INET; |
cfde141e | 975 | addr.addr = mp_opt.addr; |
1b1c7a0e PK |
976 | } |
977 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
cfde141e | 978 | else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) { |
1b1c7a0e | 979 | addr.family = AF_INET6; |
cfde141e | 980 | addr.addr6 = mp_opt.addr6; |
1b1c7a0e PK |
981 | } |
982 | #endif | |
a877de06 | 983 | if (!mp_opt.echo) { |
1b1c7a0e | 984 | mptcp_pm_add_addr_received(msk, &addr); |
a877de06 GT |
985 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); |
986 | } else { | |
00cfd77b | 987 | mptcp_pm_del_add_timer(msk, &addr); |
a877de06 GT |
988 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); |
989 | } | |
cfde141e | 990 | mp_opt.add_addr = 0; |
1b1c7a0e PK |
991 | } |
992 | ||
d0876b22 GT |
993 | if (mp_opt.rm_addr) { |
994 | mptcp_pm_rm_addr_received(msk, mp_opt.rm_id); | |
995 | mp_opt.rm_addr = 0; | |
996 | } | |
997 | ||
cfde141e | 998 | if (!mp_opt.dss) |
648ef4b8 MM |
999 | return; |
1000 | ||
cc9d2566 PA |
1001 | /* we can't wait for recvmsg() to update the ack_seq, otherwise |
1002 | * monodirectional flows will stuck | |
1003 | */ | |
cfde141e | 1004 | if (mp_opt.use_ack) |
6f8a612a | 1005 | ack_update_msk(msk, sk, &mp_opt); |
cc9d2566 | 1006 | |
06827b34 MM |
1007 | /* Zero-data-length packets are dropped by the caller and not |
1008 | * propagated to the MPTCP layer, so the skb extension does not | |
1009 | * need to be allocated or populated. DATA_FIN information, if | |
1010 | * present, needs to be updated here before the skb is freed. | |
43b54c6e MM |
1011 | */ |
1012 | if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { | |
1013 | if (mp_opt.data_fin && mp_opt.data_len == 1 && | |
1a49b2c2 | 1014 | mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && |
43b54c6e MM |
1015 | schedule_work(&msk->work)) |
1016 | sock_hold(subflow->conn); | |
06827b34 MM |
1017 | |
1018 | return; | |
43b54c6e MM |
1019 | } |
1020 | ||
648ef4b8 MM |
1021 | mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
1022 | if (!mpext) | |
1023 | return; | |
1024 | ||
1025 | memset(mpext, 0, sizeof(*mpext)); | |
1026 | ||
cfde141e PA |
1027 | if (mp_opt.use_map) { |
1028 | if (mp_opt.mpc_map) { | |
cc7972ea CP |
1029 | /* this is an MP_CAPABLE carrying MPTCP data |
1030 | * we know this map the first chunk of data | |
1031 | */ | |
1032 | mptcp_crypto_key_sha(subflow->remote_key, NULL, | |
1033 | &mpext->data_seq); | |
1034 | mpext->data_seq++; | |
1035 | mpext->subflow_seq = 1; | |
1036 | mpext->dsn64 = 1; | |
1037 | mpext->mpc_map = 1; | |
a77895db | 1038 | mpext->data_fin = 0; |
cc7972ea | 1039 | } else { |
cfde141e PA |
1040 | mpext->data_seq = mp_opt.data_seq; |
1041 | mpext->subflow_seq = mp_opt.subflow_seq; | |
1042 | mpext->dsn64 = mp_opt.dsn64; | |
1043 | mpext->data_fin = mp_opt.data_fin; | |
cc7972ea | 1044 | } |
cfde141e | 1045 | mpext->data_len = mp_opt.data_len; |
648ef4b8 | 1046 | mpext->use_map = 1; |
648ef4b8 | 1047 | } |
648ef4b8 MM |
1048 | } |
1049 | ||
fa3fe2b1 FW |
1050 | static void mptcp_set_rwin(const struct tcp_sock *tp) |
1051 | { | |
1052 | const struct sock *ssk = (const struct sock *)tp; | |
1053 | const struct mptcp_subflow_context *subflow; | |
1054 | struct mptcp_sock *msk; | |
1055 | u64 ack_seq; | |
1056 | ||
1057 | subflow = mptcp_subflow_ctx(ssk); | |
1058 | msk = mptcp_sk(subflow->conn); | |
1059 | ||
1060 | ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; | |
1061 | ||
1062 | if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) | |
1063 | WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); | |
1064 | } | |
1065 | ||
1066 | void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, | |
1067 | struct mptcp_out_options *opts) | |
eda7acdd | 1068 | { |
cc7972ea | 1069 | if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | |
eda7acdd PK |
1070 | OPTION_MPTCP_MPC_ACK) & opts->suboptions) { |
1071 | u8 len; | |
1072 | ||
1073 | if (OPTION_MPTCP_MPC_SYN & opts->suboptions) | |
1074 | len = TCPOLEN_MPTCP_MPC_SYN; | |
cec37a6e PK |
1075 | else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) |
1076 | len = TCPOLEN_MPTCP_MPC_SYNACK; | |
cc7972ea CP |
1077 | else if (opts->ext_copy.data_len) |
1078 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
eda7acdd PK |
1079 | else |
1080 | len = TCPOLEN_MPTCP_MPC_ACK; | |
1081 | ||
3df523ab PK |
1082 | *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, |
1083 | MPTCP_SUPPORTED_VERSION, | |
1084 | MPTCP_CAP_HMAC_SHA256); | |
cc7972ea CP |
1085 | |
1086 | if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & | |
1087 | opts->suboptions)) | |
1088 | goto mp_capable_done; | |
1089 | ||
eda7acdd PK |
1090 | put_unaligned_be64(opts->sndr_key, ptr); |
1091 | ptr += 2; | |
cc7972ea CP |
1092 | if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
1093 | goto mp_capable_done; | |
1094 | ||
1095 | put_unaligned_be64(opts->rcvr_key, ptr); | |
1096 | ptr += 2; | |
1097 | if (!opts->ext_copy.data_len) | |
1098 | goto mp_capable_done; | |
1099 | ||
1100 | put_unaligned_be32(opts->ext_copy.data_len << 16 | | |
1101 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
1102 | ptr += 1; | |
eda7acdd | 1103 | } |
6d0060f6 | 1104 | |
cc7972ea | 1105 | mp_capable_done: |
e1ef6832 GT |
1106 | if ((OPTION_MPTCP_ADD_ADDR |
1107 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) | |
1108 | | OPTION_MPTCP_ADD_ADDR6 | |
1109 | #endif | |
1110 | ) & opts->suboptions) { | |
6eb3d1e3 GT |
1111 | u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; |
1112 | u8 echo = MPTCP_ADDR_ECHO; | |
1113 | ||
e1ef6832 GT |
1114 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
1115 | if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) | |
1116 | len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; | |
1117 | #endif | |
1118 | ||
22fb85ff GT |
1119 | if (opts->port) |
1120 | len += TCPOLEN_MPTCP_PORT_LEN; | |
1121 | ||
3df523ab | 1122 | if (opts->ahmac) { |
6eb3d1e3 GT |
1123 | len += sizeof(opts->ahmac); |
1124 | echo = 0; | |
3df523ab | 1125 | } |
3df523ab | 1126 | |
6eb3d1e3 GT |
1127 | *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, |
1128 | len, echo, opts->addr_id); | |
e1ef6832 GT |
1129 | if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { |
1130 | memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4); | |
1131 | ptr += 1; | |
3df523ab | 1132 | } |
3df523ab | 1133 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
e1ef6832 GT |
1134 | else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) { |
1135 | memcpy((u8 *)ptr, opts->addr6.s6_addr, 16); | |
1136 | ptr += 4; | |
3df523ab | 1137 | } |
3df523ab PK |
1138 | #endif |
1139 | ||
22fb85ff GT |
1140 | if (!opts->port) { |
1141 | if (opts->ahmac) { | |
1142 | put_unaligned_be64(opts->ahmac, ptr); | |
1143 | ptr += 2; | |
1144 | } | |
1145 | } else { | |
1146 | if (opts->ahmac) { | |
1147 | u8 *bptr = (u8 *)ptr; | |
1148 | ||
1149 | put_unaligned_be16(opts->port, bptr); | |
1150 | bptr += 2; | |
1151 | put_unaligned_be64(opts->ahmac, bptr); | |
1152 | bptr += 8; | |
1153 | put_unaligned_be16(TCPOPT_NOP << 8 | | |
1154 | TCPOPT_NOP, bptr); | |
1155 | ||
1156 | ptr += 3; | |
1157 | } else { | |
1158 | put_unaligned_be32(opts->port << 16 | | |
1159 | TCPOPT_NOP << 8 | | |
1160 | TCPOPT_NOP, ptr); | |
1161 | ptr += 1; | |
1162 | } | |
3df523ab PK |
1163 | } |
1164 | } | |
3df523ab PK |
1165 | |
1166 | if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { | |
1167 | *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, | |
1168 | TCPOLEN_MPTCP_RM_ADDR_BASE, | |
1169 | 0, opts->rm_id); | |
1170 | } | |
1171 | ||
ec3edaa7 PK |
1172 | if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { |
1173 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1174 | TCPOLEN_MPTCP_MPJ_SYN, | |
1175 | opts->backup, opts->join_id); | |
1176 | put_unaligned_be32(opts->token, ptr); | |
1177 | ptr += 1; | |
1178 | put_unaligned_be32(opts->nonce, ptr); | |
1179 | ptr += 1; | |
1180 | } | |
1181 | ||
f296234c PK |
1182 | if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { |
1183 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1184 | TCPOLEN_MPTCP_MPJ_SYNACK, | |
1185 | opts->backup, opts->join_id); | |
1186 | put_unaligned_be64(opts->thmac, ptr); | |
1187 | ptr += 2; | |
1188 | put_unaligned_be32(opts->nonce, ptr); | |
1189 | ptr += 1; | |
1190 | } | |
1191 | ||
ec3edaa7 PK |
1192 | if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { |
1193 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, | |
1194 | TCPOLEN_MPTCP_MPJ_ACK, 0, 0); | |
1195 | memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); | |
1196 | ptr += 5; | |
1197 | } | |
1198 | ||
6d0060f6 MM |
1199 | if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { |
1200 | struct mptcp_ext *mpext = &opts->ext_copy; | |
1201 | u8 len = TCPOLEN_MPTCP_DSS_BASE; | |
1202 | u8 flags = 0; | |
1203 | ||
1204 | if (mpext->use_ack) { | |
a0c1d0ea CP |
1205 | flags = MPTCP_DSS_HAS_ACK; |
1206 | if (mpext->ack64) { | |
1207 | len += TCPOLEN_MPTCP_DSS_ACK64; | |
1208 | flags |= MPTCP_DSS_ACK64; | |
1209 | } else { | |
1210 | len += TCPOLEN_MPTCP_DSS_ACK32; | |
1211 | } | |
6d0060f6 MM |
1212 | } |
1213 | ||
1214 | if (mpext->use_map) { | |
1215 | len += TCPOLEN_MPTCP_DSS_MAP64; | |
1216 | ||
1217 | /* Use only 64-bit mapping flags for now, add | |
1218 | * support for optional 32-bit mappings later. | |
1219 | */ | |
1220 | flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; | |
1221 | if (mpext->data_fin) | |
1222 | flags |= MPTCP_DSS_DATA_FIN; | |
1223 | } | |
1224 | ||
3df523ab | 1225 | *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); |
6d0060f6 MM |
1226 | |
1227 | if (mpext->use_ack) { | |
a0c1d0ea CP |
1228 | if (mpext->ack64) { |
1229 | put_unaligned_be64(mpext->data_ack, ptr); | |
1230 | ptr += 2; | |
1231 | } else { | |
1232 | put_unaligned_be32(mpext->data_ack32, ptr); | |
1233 | ptr += 1; | |
1234 | } | |
6d0060f6 MM |
1235 | } |
1236 | ||
1237 | if (mpext->use_map) { | |
1238 | put_unaligned_be64(mpext->data_seq, ptr); | |
1239 | ptr += 2; | |
1240 | put_unaligned_be32(mpext->subflow_seq, ptr); | |
1241 | ptr += 1; | |
1242 | put_unaligned_be32(mpext->data_len << 16 | | |
1243 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
1244 | } | |
1245 | } | |
fa3fe2b1 FW |
1246 | |
1247 | if (tp) | |
1248 | mptcp_set_rwin(tp); | |
eda7acdd | 1249 | } |