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mptcp: change add_addr_signal type
[linux-2.6-block.git] / net / mptcp / options.c
CommitLineData
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>
bd697222 10#include <crypto/sha.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		 16static bool mptcp_cap_flag_sha256(u8 flags)
17{
18 return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
19}
20
cfde141e
PA		 21static 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++;
6a6c05a8 245 pr_debug("ADD_ADDR: id=%d, echo=%d", mp_opt->addr_id, mp_opt->echo);
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 }
270 break;
271
272 case MPTCPOPT_RM_ADDR:
273 if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
274 break;
275
8e60eed6
GT		 276 ptr++;
277
3df523ab
PK		 278 mp_opt->rm_addr = 1;
279 mp_opt->rm_id = *ptr++;
280 pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
281 break;
282
eda7acdd
PK		 283 default:
284 break;
285 }
286}
287
cec37a6e 288void mptcp_get_options(const struct sk_buff *skb,
cfde141e 289 struct mptcp_options_received *mp_opt)
cec37a6e 290{
cec37a6e 291 const struct tcphdr *th = tcp_hdr(skb);
cfde141e
PA		 292 const unsigned char *ptr;
293 int length;
cec37a6e 294
cfde141e
PA		 295 /* initialize option status */
296 mp_opt->mp_capable = 0;
297 mp_opt->mp_join = 0;
298 mp_opt->add_addr = 0;
fe2d9b1a 299 mp_opt->ahmac = 0;
65b8c8a6 300 mp_opt->port = 0;
cfde141e
PA		 301 mp_opt->rm_addr = 0;
302 mp_opt->dss = 0;
303
304 length = (th->doff * 4) - sizeof(struct tcphdr);
cec37a6e
PK		 305 ptr = (const unsigned char *)(th + 1);
306
307 while (length > 0) {
308 int opcode = *ptr++;
309 int opsize;
310
311 switch (opcode) {
312 case TCPOPT_EOL:
313 return;
314 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
315 length--;
316 continue;
317 default:
318 opsize = *ptr++;
319 if (opsize < 2) /* "silly options" */
320 return;
321 if (opsize > length)
322 return; /* don't parse partial options */
323 if (opcode == TCPOPT_MPTCP)
cfde141e 324 mptcp_parse_option(skb, ptr, opsize, mp_opt);
cec37a6e
PK		 325 ptr += opsize - 2;
326 length -= opsize;
327 }
328 }
329}
330
cc7972ea
CP		 331bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
332 unsigned int *size, struct mptcp_out_options *opts)
cec37a6e
PK		 333{
334 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
335
cc7972ea
CP		 336 /* we will use snd_isn to detect first pkt [re]transmission
337 * in mptcp_established_options_mp()
338 */
339 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq;
cec37a6e 340 if (subflow->request_mptcp) {
cec37a6e 341 opts->suboptions = OPTION_MPTCP_MPC_SYN;
cec37a6e
PK		 342 *size = TCPOLEN_MPTCP_MPC_SYN;
343 return true;
ec3edaa7
PK		 344 } else if (subflow->request_join) {
345 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
346 subflow->local_nonce);
347 opts->suboptions = OPTION_MPTCP_MPJ_SYN;
348 opts->join_id = subflow->local_id;
349 opts->token = subflow->remote_token;
350 opts->nonce = subflow->local_nonce;
351 opts->backup = subflow->request_bkup;
352 *size = TCPOLEN_MPTCP_MPJ_SYN;
353 return true;
cec37a6e
PK		 354 }
355 return false;
356}
357
ec3edaa7
PK		 358/* MP_JOIN client subflow must wait for 4th ack before sending any data:
359 * TCP can't schedule delack timer before the subflow is fully established.
360 * MPTCP uses the delack timer to do 3rd ack retransmissions
361 */
362static void schedule_3rdack_retransmission(struct sock *sk)
363{
364 struct inet_connection_sock *icsk = inet_csk(sk);
365 struct tcp_sock *tp = tcp_sk(sk);
366 unsigned long timeout;
367
368 /* reschedule with a timeout above RTT, as we must look only for drop */
369 if (tp->srtt_us)
370 timeout = tp->srtt_us << 1;
371 else
372 timeout = TCP_TIMEOUT_INIT;
373
374 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
375 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
376 icsk->icsk_ack.timeout = timeout;
377 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
378}
379
380static void clear_3rdack_retransmission(struct sock *sk)
381{
382 struct inet_connection_sock *icsk = inet_csk(sk);
383
384 sk_stop_timer(sk, &icsk->icsk_delack_timer);
385 icsk->icsk_ack.timeout = 0;
386 icsk->icsk_ack.ato = 0;
387 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER);
388}
389
cc7972ea
CP		 390static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
391 unsigned int *size,
6d0060f6
MM		 392 unsigned int remaining,
393 struct mptcp_out_options *opts)
cec37a6e
PK		 394{
395 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
cc7972ea
CP		 396 struct mptcp_ext *mpext;
397 unsigned int data_len;
398
ec3edaa7
PK		 399 /* When skb is not available, we better over-estimate the emitted
400 * options len. A full DSS option (28 bytes) is longer than
401 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so
402 * tell the caller to defer the estimate to
403 * mptcp_established_options_dss(), which will reserve enough space.
404 */
405 if (!skb)
406 return false;
cc7972ea 407
ec3edaa7
PK		 408 /* MPC/MPJ needed only on 3rd ack packet */
409 if (subflow->fully_established ||
410 subflow->snd_isn != TCP_SKB_CB(skb)->seq)
411 return false;
412
413 if (subflow->mp_capable) {
cc7972ea
CP		 414 mpext = mptcp_get_ext(skb);
415 data_len = mpext ? mpext->data_len : 0;
cec37a6e 416
cc7972ea
CP		 417 /* we will check ext_copy.data_len in mptcp_write_options() to
418 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
419 * TCPOLEN_MPTCP_MPC_ACK
420 */
421 opts->ext_copy.data_len = data_len;
cec37a6e
PK		 422 opts->suboptions = OPTION_MPTCP_MPC_ACK;
423 opts->sndr_key = subflow->local_key;
424 opts->rcvr_key = subflow->remote_key;
cc7972ea
CP		 425
426 /* Section 3.1.
427 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK
428 * packets that start the first subflow of an MPTCP connection,
429 * as well as the first packet that carries data
430 */
431 if (data_len > 0)
432 *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4);
433 else
434 *size = TCPOLEN_MPTCP_MPC_ACK;
435
436 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d",
437 subflow, subflow->local_key, subflow->remote_key,
438 data_len);
439
cec37a6e 440 return true;
ec3edaa7
PK		 441 } else if (subflow->mp_join) {
442 opts->suboptions = OPTION_MPTCP_MPJ_ACK;
443 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
444 *size = TCPOLEN_MPTCP_MPJ_ACK;
445 pr_debug("subflow=%p", subflow);
446
447 schedule_3rdack_retransmission(sk);
448 return true;
cec37a6e
PK		 449 }
450 return false;
451}
452
6d0060f6 453static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
9c29e361 454 struct sk_buff *skb, struct mptcp_ext *ext)
6d0060f6 455{
017512a0
PA		 456 /* The write_seq value has already been incremented, so the actual
457 * sequence number for the DATA_FIN is one less.
458 */
459 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
7279da61 460
9c29e361 461 if (!ext->use_map || !skb->len) {
6d0060f6
MM		 462 /* RFC6824 requires a DSS mapping with specific values
463 * if DATA_FIN is set but no data payload is mapped
464 */
6d37a0b8 465 ext->data_fin = 1;
6d0060f6
MM		 466 ext->use_map = 1;
467 ext->dsn64 = 1;
017512a0 468 ext->data_seq = data_fin_tx_seq;
6d0060f6
MM		 469 ext->subflow_seq = 0;
470 ext->data_len = 1;
7279da61 471 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
6d37a0b8
MM		 472 /* If there's an existing DSS mapping and it is the
473 * final mapping, DATA_FIN consumes 1 additional byte of
474 * mapping space.
6d0060f6 475 */
6d37a0b8 476 ext->data_fin = 1;
6d0060f6
MM		 477 ext->data_len++;
478 }
479}
480
481static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
482 unsigned int *size,
483 unsigned int remaining,
484 struct mptcp_out_options *opts)
485{
486 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
7279da61 487 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
6d0060f6 488 unsigned int dss_size = 0;
7279da61 489 u64 snd_data_fin_enable;
6d0060f6 490 struct mptcp_ext *mpext;
6d0060f6 491 unsigned int ack_size;
d22f4988 492 bool ret = false;
6d0060f6 493
0bac966a 494 mpext = skb ? mptcp_get_ext(skb) : NULL;
e16163b6 495 snd_data_fin_enable = mptcp_data_fin_enabled(msk);
6d0060f6 496
7279da61 497 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
6d0060f6
MM		 498 unsigned int map_size;
499
500 map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
501
502 remaining -= map_size;
503 dss_size = map_size;
504 if (mpext)
505 opts->ext_copy = *mpext;
506
7279da61 507 if (skb && snd_data_fin_enable)
9c29e361 508 mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
d22f4988
CP		 509 ret = true;
510 }
511
2398e399
PA		 512 /* passive sockets msk will set the 'can_ack' after accept(), even
513 * if the first subflow may have the already the remote key handy
514 */
d22f4988 515 opts->ext_copy.use_ack = 0;
dc093db5 516 if (!READ_ONCE(msk->can_ack)) {
d22f4988
CP		 517 *size = ALIGN(dss_size, 4);
518 return ret;
6d0060f6
MM		 519 }
520
37198e93 521 if (READ_ONCE(msk->use_64bit_ack)) {
a0c1d0ea 522 ack_size = TCPOLEN_MPTCP_DSS_ACK64;
917944da 523 opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
a0c1d0ea
CP		 524 opts->ext_copy.ack64 = 1;
525 } else {
526 ack_size = TCPOLEN_MPTCP_DSS_ACK32;
917944da 527 opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
a0c1d0ea
CP		 528 opts->ext_copy.ack64 = 0;
529 }
530 opts->ext_copy.use_ack = 1;
6d0060f6
MM		 531
532 /* Add kind/length/subtype/flag overhead if mapping is not populated */
533 if (dss_size == 0)
534 ack_size += TCPOLEN_MPTCP_DSS_BASE;
535
536 dss_size += ack_size;
537
6d0060f6
MM		 538 *size = ALIGN(dss_size, 4);
539 return true;
540}
541
3df523ab
PK		 542static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id,
543 struct in_addr *addr)
544{
bd697222 545 u8 hmac[SHA256_DIGEST_SIZE];
3df523ab
PK		 546 u8 msg[7];
547
548 msg[0] = addr_id;
549 memcpy(&msg[1], &addr->s_addr, 4);
550 msg[5] = 0;
551 msg[6] = 0;
552
553 mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);
554
bd697222 555 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
3df523ab
PK		 556}
557
558#if IS_ENABLED(CONFIG_MPTCP_IPV6)
559static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
560 struct in6_addr *addr)
561{
bd697222 562 u8 hmac[SHA256_DIGEST_SIZE];
3df523ab
PK		 563 u8 msg[19];
564
565 msg[0] = addr_id;
566 memcpy(&msg[1], &addr->s6_addr, 16);
567 msg[17] = 0;
568 msg[18] = 0;
569
570 mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);
571
bd697222 572 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
3df523ab
PK		 573}
574#endif
575
f643b803
GT		 576static bool mptcp_established_options_add_addr(struct sock *sk,
577 unsigned int *size,
578 unsigned int remaining,
579 struct mptcp_out_options *opts)
3df523ab
PK		 580{
581 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
582 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1b1c7a0e 583 struct mptcp_addr_info saddr;
6a6c05a8 584 bool echo;
1b1c7a0e 585 int len;
3df523ab 586
f643b803 587 if (!mptcp_pm_should_add_signal(msk) ||
6a6c05a8 588 !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo)))
1b1c7a0e
PK		 589 return false;
590
456afe01 591 len = mptcp_add_addr_len(saddr.family, echo);
1b1c7a0e
PK		 592 if (remaining < len)
593 return false;
3df523ab 594
1b1c7a0e
PK		 595 *size = len;
596 opts->addr_id = saddr.id;
597 if (saddr.family == AF_INET) {
3df523ab 598 opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
1b1c7a0e 599 opts->addr = saddr.addr;
6a6c05a8
GT		 600 if (!echo) {
601 opts->ahmac = add_addr_generate_hmac(msk->local_key,
602 msk->remote_key,
603 opts->addr_id,
604 &opts->addr);
605 }
3df523ab
PK		 606 }
607#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1b1c7a0e 608 else if (saddr.family == AF_INET6) {
3df523ab 609 opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
1b1c7a0e 610 opts->addr6 = saddr.addr6;
6a6c05a8
GT		 611 if (!echo) {
612 opts->ahmac = add_addr6_generate_hmac(msk->local_key,
613 msk->remote_key,
614 opts->addr_id,
615 &opts->addr6);
616 }
3df523ab
PK		 617 }
618#endif
6a6c05a8 619 pr_debug("addr_id=%d, ahmac=%llu, echo=%d", opts->addr_id, opts->ahmac, echo);
3df523ab
PK		 620
621 return true;
622}
623
5cb104ae
GT		 624static bool mptcp_established_options_rm_addr(struct sock *sk,
625 unsigned int *size,
626 unsigned int remaining,
627 struct mptcp_out_options *opts)
628{
629 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
630 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
631 u8 rm_id;
632
633 if (!mptcp_pm_should_rm_signal(msk) ||
634 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id)))
635 return false;
636
637 if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
638 return false;
639
640 *size = TCPOLEN_MPTCP_RM_ADDR_BASE;
641 opts->suboptions |= OPTION_MPTCP_RM_ADDR;
642 opts->rm_id = rm_id;
643
644 pr_debug("rm_id=%d", opts->rm_id);
645
646 return true;
647}
648
6d0060f6
MM		 649bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
650 unsigned int *size, unsigned int remaining,
651 struct mptcp_out_options *opts)
652{
653 unsigned int opt_size = 0;
654 bool ret = false;
655
3df523ab
PK		 656 opts->suboptions = 0;
657
e1ff9e82
DC		 658 if (unlikely(mptcp_check_fallback(sk)))
659 return false;
660
d5824847
PA		 661 /* prevent adding of any MPTCP related options on reset packet
662 * until we support MP_TCPRST/MP_FASTCLOSE
663 */
664 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
665 return false;
666
cc7972ea 667 if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
6d0060f6
MM		 668 ret = true;
669 else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
670 opts))
671 ret = true;
672
673 /* we reserved enough space for the above options, and exceeding the
674 * TCP option space would be fatal
675 */
676 if (WARN_ON_ONCE(opt_size > remaining))
677 return false;
678
679 *size += opt_size;
680 remaining -= opt_size;
f643b803 681 if (mptcp_established_options_add_addr(sk, &opt_size, remaining, opts)) {
3df523ab
PK		 682 *size += opt_size;
683 remaining -= opt_size;
684 ret = true;
5cb104ae
GT		 685 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
686 *size += opt_size;
687 remaining -= opt_size;
688 ret = true;
3df523ab 689 }
6d0060f6
MM		 690
691 return ret;
692}
693
cec37a6e
PK		 694bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
695 struct mptcp_out_options *opts)
696{
697 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
698
699 if (subflow_req->mp_capable) {
700 opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
701 opts->sndr_key = subflow_req->local_key;
702 *size = TCPOLEN_MPTCP_MPC_SYNACK;
703 pr_debug("subflow_req=%p, local_key=%llu",
704 subflow_req, subflow_req->local_key);
705 return true;
f296234c
PK		 706 } else if (subflow_req->mp_join) {
707 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
708 opts->backup = subflow_req->backup;
709 opts->join_id = subflow_req->local_id;
710 opts->thmac = subflow_req->thmac;
711 opts->nonce = subflow_req->local_nonce;
712 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
713 subflow_req, opts->backup, opts->join_id,
714 opts->thmac, opts->nonce);
715 *size = TCPOLEN_MPTCP_MPJ_SYNACK;
716 return true;
cec37a6e
PK		 717 }
718 return false;
719}
720
d5824847 721static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
f296234c 722 struct mptcp_subflow_context *subflow,
0be534f5
PA		 723 struct sk_buff *skb,
724 struct mptcp_options_received *mp_opt)
d22f4988
CP		 725{
726 /* here we can process OoO, in-window pkts, only in-sequence 4th ack
f296234c 727 * will make the subflow fully established
d22f4988 728 */
f296234c
PK		 729 if (likely(subflow->fully_established)) {
730 /* on passive sockets, check for 3rd ack retransmission
731 * note that msk is always set by subflow_syn_recv_sock()
732 * for mp_join subflows
733 */
734 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
735 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
736 subflow->mp_join && mp_opt->mp_join &&
737 READ_ONCE(msk->pm.server_side))
d5824847 738 tcp_send_ack(ssk);
f296234c
PK		 739 goto fully_established;
740 }
741
d5824847
PA		 742 /* we must process OoO packets before the first subflow is fully
743 * established. OoO packets are instead a protocol violation
744 * for MP_JOIN subflows as the peer must not send any data
745 * before receiving the forth ack - cfr. RFC 8684 section 3.2.
f296234c 746 */
d5824847
PA		 747 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
748 if (subflow->mp_join)
749 goto reset;
f296234c 750 return subflow->mp_capable;
d5824847 751 }
d22f4988 752
5a91e32b 753 if (mp_opt->dss && mp_opt->use_ack) {
f296234c
PK		 754 /* subflows are fully established as soon as we get any
755 * additional ack.
756 */
0be534f5 757 subflow->fully_established = 1;
b93df08c 758 WRITE_ONCE(msk->fully_established, true);
f296234c
PK		 759 goto fully_established;
760 }
d22f4988 761
d22f4988 762 /* If the first established packet does not contain MP_CAPABLE + data
d5824847
PA		 763 * then fallback to TCP. Fallback scenarios requires a reset for
764 * MP_JOIN subflows.
d22f4988
CP		 765 */
766 if (!mp_opt->mp_capable) {
d5824847
PA		 767 if (subflow->mp_join)
768 goto reset;
d22f4988 769 subflow->mp_capable = 0;
e1ff9e82
DC		 770 pr_fallback(msk);
771 __mptcp_do_fallback(msk);
d22f4988
CP		 772 return false;
773 }
f296234c 774
d6085fe1
PA		 775 if (unlikely(!READ_ONCE(msk->pm.server_side)))
776 pr_warn_once("bogus mpc option on established client sk");
b93df08c 777 mptcp_subflow_fully_established(subflow, mp_opt);
f296234c
PK		 778
779fully_established:
780 if (likely(subflow->pm_notified))
781 return true;
782
783 subflow->pm_notified = 1;
ec3edaa7 784 if (subflow->mp_join) {
d5824847 785 clear_3rdack_retransmission(ssk);
f296234c 786 mptcp_pm_subflow_established(msk, subflow);
ec3edaa7 787 } else {
f296234c 788 mptcp_pm_fully_established(msk);
ec3edaa7 789 }
d22f4988 790 return true;
d5824847
PA		 791
792reset:
793 mptcp_subflow_reset(ssk);
794 return false;
d22f4988
CP		 795}
796
cc9d2566
PA		 797static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
798{
799 u32 old_ack32, cur_ack32;
800
801 if (use_64bit)
802 return cur_ack;
803
804 old_ack32 = (u32)old_ack;
805 cur_ack32 = (u32)cur_ack;
806 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
807 if (unlikely(before(cur_ack32, old_ack32)))
808 return cur_ack + (1LL << 32);
809 return cur_ack;
810}
811
6f8a612a
FW		 812static void ack_update_msk(struct mptcp_sock *msk,
813 const struct sock *ssk,
814 struct mptcp_options_received *mp_opt)
cc9d2566
PA		 815{
816 u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una);
6f8a612a 817 u64 new_wnd_end, wnd_end, old_wnd_end = atomic64_read(&msk->wnd_end);
eaa2ffab 818 u64 snd_nxt = READ_ONCE(msk->snd_nxt);
6f8a612a 819 struct sock *sk = (struct sock *)msk;
cc9d2566
PA		 820
821 /* avoid ack expansion on update conflict, to reduce the risk of
822 * wrongly expanding to a future ack sequence number, which is way
823 * more dangerous than missing an ack
824 */
825 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
826
827 /* ACK for data not even sent yet? Ignore. */
eaa2ffab 828 if (after64(new_snd_una, snd_nxt))
cc9d2566
PA		 829 new_snd_una = old_snd_una;
830
6f8a612a
FW		 831 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
832
833 while (after64(new_wnd_end, old_wnd_end)) {
834 wnd_end = old_wnd_end;
835 old_wnd_end = atomic64_cmpxchg(&msk->wnd_end, wnd_end,
836 new_wnd_end);
837 if (old_wnd_end == wnd_end) {
838 if (mptcp_send_head(sk))
839 mptcp_schedule_work(sk);
840 break;
841 }
842 }
843
cc9d2566
PA		 844 while (after64(new_snd_una, old_snd_una)) {
845 snd_una = old_snd_una;
846 old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una,
847 new_snd_una);
b51f9b80 848 if (old_snd_una == snd_una) {
6f8a612a 849 mptcp_data_acked(sk);
cc9d2566 850 break;
b51f9b80 851 }
cc9d2566
PA		 852 }
853}
854
1a49b2c2 855bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
3721b9b6
MM		 856{
857 /* Skip if DATA_FIN was already received.
858 * If updating simultaneously with the recvmsg loop, values
859 * should match. If they mismatch, the peer is misbehaving and
860 * we will prefer the most recent information.
861 */
862 if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))
863 return false;
864
1a49b2c2
MM		 865 WRITE_ONCE(msk->rcv_data_fin_seq,
866 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
3721b9b6
MM		 867 WRITE_ONCE(msk->rcv_data_fin, 1);
868
869 return true;
870}
871
1b1c7a0e
PK		 872static bool add_addr_hmac_valid(struct mptcp_sock *msk,
873 struct mptcp_options_received *mp_opt)
874{
875 u64 hmac = 0;
876
877 if (mp_opt->echo)
878 return true;
879
880 if (mp_opt->family == MPTCP_ADDR_IPVERSION_4)
881 hmac = add_addr_generate_hmac(msk->remote_key,
882 msk->local_key,
883 mp_opt->addr_id, &mp_opt->addr);
884#if IS_ENABLED(CONFIG_MPTCP_IPV6)
885 else
886 hmac = add_addr6_generate_hmac(msk->remote_key,
887 msk->local_key,
888 mp_opt->addr_id, &mp_opt->addr6);
889#endif
890
891 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
892 msk, (unsigned long long)hmac,
893 (unsigned long long)mp_opt->ahmac);
894
895 return hmac == mp_opt->ahmac;
896}
897
77d0cab9 898void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
648ef4b8 899{
d22f4988 900 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1b1c7a0e 901 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
cfde141e 902 struct mptcp_options_received mp_opt;
648ef4b8
MM		 903 struct mptcp_ext *mpext;
904
e1ff9e82
DC		 905 if (__mptcp_check_fallback(msk))
906 return;
907
cfde141e
PA		 908 mptcp_get_options(skb, &mp_opt);
909 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
d22f4988 910 return;
648ef4b8 911
cfde141e 912 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) {
1b1c7a0e
PK		 913 struct mptcp_addr_info addr;
914
cfde141e
PA		 915 addr.port = htons(mp_opt.port);
916 addr.id = mp_opt.addr_id;
917 if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) {
1b1c7a0e 918 addr.family = AF_INET;
cfde141e 919 addr.addr = mp_opt.addr;
1b1c7a0e
PK		 920 }
921#if IS_ENABLED(CONFIG_MPTCP_IPV6)
cfde141e 922 else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) {
1b1c7a0e 923 addr.family = AF_INET6;
cfde141e 924 addr.addr6 = mp_opt.addr6;
1b1c7a0e
PK		 925 }
926#endif
a877de06 927 if (!mp_opt.echo) {
1b1c7a0e 928 mptcp_pm_add_addr_received(msk, &addr);
a877de06
GT		 929 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
930 } else {
00cfd77b 931 mptcp_pm_del_add_timer(msk, &addr);
a877de06
GT		 932 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
933 }
cfde141e 934 mp_opt.add_addr = 0;
1b1c7a0e
PK		 935 }
936
d0876b22
GT		 937 if (mp_opt.rm_addr) {
938 mptcp_pm_rm_addr_received(msk, mp_opt.rm_id);
939 mp_opt.rm_addr = 0;
940 }
941
cfde141e 942 if (!mp_opt.dss)
648ef4b8
MM		 943 return;
944
cc9d2566
PA		 945 /* we can't wait for recvmsg() to update the ack_seq, otherwise
946 * monodirectional flows will stuck
947 */
cfde141e 948 if (mp_opt.use_ack)
6f8a612a 949 ack_update_msk(msk, sk, &mp_opt);
cc9d2566 950
06827b34
MM		 951 /* Zero-data-length packets are dropped by the caller and not
952 * propagated to the MPTCP layer, so the skb extension does not
953 * need to be allocated or populated. DATA_FIN information, if
954 * present, needs to be updated here before the skb is freed.
43b54c6e
MM		 955 */
956 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
957 if (mp_opt.data_fin && mp_opt.data_len == 1 &&
1a49b2c2 958 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
43b54c6e
MM		 959 schedule_work(&msk->work))
960 sock_hold(subflow->conn);
06827b34
MM		 961
962 return;
43b54c6e
MM		 963 }
964
648ef4b8
MM		 965 mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
966 if (!mpext)
967 return;
968
969 memset(mpext, 0, sizeof(*mpext));
970
cfde141e
PA		 971 if (mp_opt.use_map) {
972 if (mp_opt.mpc_map) {
cc7972ea
CP		 973 /* this is an MP_CAPABLE carrying MPTCP data
974 * we know this map the first chunk of data
975 */
976 mptcp_crypto_key_sha(subflow->remote_key, NULL,
977 &mpext->data_seq);
978 mpext->data_seq++;
979 mpext->subflow_seq = 1;
980 mpext->dsn64 = 1;
981 mpext->mpc_map = 1;
a77895db 982 mpext->data_fin = 0;
cc7972ea 983 } else {
cfde141e
PA		 984 mpext->data_seq = mp_opt.data_seq;
985 mpext->subflow_seq = mp_opt.subflow_seq;
986 mpext->dsn64 = mp_opt.dsn64;
987 mpext->data_fin = mp_opt.data_fin;
cc7972ea 988 }
cfde141e 989 mpext->data_len = mp_opt.data_len;
648ef4b8 990 mpext->use_map = 1;
648ef4b8 991 }
648ef4b8
MM		 992}
993
eda7acdd
PK		 994void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
995{
cc7972ea 996 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK |
eda7acdd
PK		 997 OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
998 u8 len;
999
1000 if (OPTION_MPTCP_MPC_SYN & opts->suboptions)
1001 len = TCPOLEN_MPTCP_MPC_SYN;
cec37a6e
PK		 1002 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions)
1003 len = TCPOLEN_MPTCP_MPC_SYNACK;
cc7972ea
CP		 1004 else if (opts->ext_copy.data_len)
1005 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
eda7acdd
PK		 1006 else
1007 len = TCPOLEN_MPTCP_MPC_ACK;
1008
3df523ab
PK		 1009 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
1010 MPTCP_SUPPORTED_VERSION,
1011 MPTCP_CAP_HMAC_SHA256);
cc7972ea
CP		 1012
1013 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
1014 opts->suboptions))
1015 goto mp_capable_done;
1016
eda7acdd
PK		 1017 put_unaligned_be64(opts->sndr_key, ptr);
1018 ptr += 2;
cc7972ea
CP		 1019 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
1020 goto mp_capable_done;
1021
1022 put_unaligned_be64(opts->rcvr_key, ptr);
1023 ptr += 2;
1024 if (!opts->ext_copy.data_len)
1025 goto mp_capable_done;
1026
1027 put_unaligned_be32(opts->ext_copy.data_len << 16 |
1028 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1029 ptr += 1;
eda7acdd 1030 }
6d0060f6 1031
cc7972ea 1032mp_capable_done:
3df523ab
PK		 1033 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
1034 if (opts->ahmac)
1035 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1036 TCPOLEN_MPTCP_ADD_ADDR, 0,
1037 opts->addr_id);
1038 else
1039 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1040 TCPOLEN_MPTCP_ADD_ADDR_BASE,
1041 MPTCP_ADDR_ECHO,
1042 opts->addr_id);
1043 memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
1044 ptr += 1;
1045 if (opts->ahmac) {
1046 put_unaligned_be64(opts->ahmac, ptr);
1047 ptr += 2;
1048 }
1049 }
1050
1051#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1052 if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
1053 if (opts->ahmac)
1054 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1055 TCPOLEN_MPTCP_ADD_ADDR6, 0,
1056 opts->addr_id);
1057 else
1058 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1059 TCPOLEN_MPTCP_ADD_ADDR6_BASE,
1060 MPTCP_ADDR_ECHO,
1061 opts->addr_id);
1062 memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
1063 ptr += 4;
1064 if (opts->ahmac) {
1065 put_unaligned_be64(opts->ahmac, ptr);
1066 ptr += 2;
1067 }
1068 }
1069#endif
1070
1071 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
1072 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
1073 TCPOLEN_MPTCP_RM_ADDR_BASE,
1074 0, opts->rm_id);
1075 }
1076
ec3edaa7
PK		 1077 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
1078 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1079 TCPOLEN_MPTCP_MPJ_SYN,
1080 opts->backup, opts->join_id);
1081 put_unaligned_be32(opts->token, ptr);
1082 ptr += 1;
1083 put_unaligned_be32(opts->nonce, ptr);
1084 ptr += 1;
1085 }
1086
f296234c
PK		 1087 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
1088 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1089 TCPOLEN_MPTCP_MPJ_SYNACK,
1090 opts->backup, opts->join_id);
1091 put_unaligned_be64(opts->thmac, ptr);
1092 ptr += 2;
1093 put_unaligned_be32(opts->nonce, ptr);
1094 ptr += 1;
1095 }
1096
ec3edaa7
PK		 1097 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
1098 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1099 TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
1100 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
1101 ptr += 5;
1102 }
1103
6d0060f6
MM		 1104 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
1105 struct mptcp_ext *mpext = &opts->ext_copy;
1106 u8 len = TCPOLEN_MPTCP_DSS_BASE;
1107 u8 flags = 0;
1108
1109 if (mpext->use_ack) {
a0c1d0ea
CP		 1110 flags = MPTCP_DSS_HAS_ACK;
1111 if (mpext->ack64) {
1112 len += TCPOLEN_MPTCP_DSS_ACK64;
1113 flags |= MPTCP_DSS_ACK64;
1114 } else {
1115 len += TCPOLEN_MPTCP_DSS_ACK32;
1116 }
6d0060f6
MM		 1117 }
1118
1119 if (mpext->use_map) {
1120 len += TCPOLEN_MPTCP_DSS_MAP64;
1121
1122 /* Use only 64-bit mapping flags for now, add
1123 * support for optional 32-bit mappings later.
1124 */
1125 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
1126 if (mpext->data_fin)
1127 flags |= MPTCP_DSS_DATA_FIN;
1128 }
1129
3df523ab 1130 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
6d0060f6
MM		 1131
1132 if (mpext->use_ack) {
a0c1d0ea
CP		 1133 if (mpext->ack64) {
1134 put_unaligned_be64(mpext->data_ack, ptr);
1135 ptr += 2;
1136 } else {
1137 put_unaligned_be32(mpext->data_ack32, ptr);
1138 ptr += 1;
1139 }
6d0060f6
MM		 1140 }
1141
1142 if (mpext->use_map) {
1143 put_unaligned_be64(mpext->data_seq, ptr);
1144 ptr += 2;
1145 put_unaligned_be32(mpext->subflow_seq, ptr);
1146 ptr += 1;
1147 put_unaligned_be32(mpext->data_len << 16 |
1148 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1149 }
1150 }
eda7acdd 1151}
Linux 6.x block layer and io_uring tree(s)