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io_uring: ensure finish_wait() is always called in __io_uring_task_cancel()
[linux/fpc-iii.git] / net / mptcp / options.c
blobe0d21c0607e5397f620c31ca8f2e10cb1d03a50c
1 // SPDX-License-Identifier: GPL-2.0
2 /* Multipath TCP
3 *
4 * Copyright (c) 2017 - 2019, Intel Corporation.
5 */
6
7 #define pr_fmt(fmt) "MPTCP: " fmt
8
9 #include <linux/kernel.h>
10 #include <crypto/sha2.h>
11 #include <net/tcp.h>
12 #include <net/mptcp.h>
13 #include "protocol.h"
14 #include "mib.h"
15
16 static bool mptcp_cap_flag_sha256(u8 flags)
17 {
18 return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
19 }
20
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)
24 {
25 u8 subtype = *ptr >> 4;
26 int expected_opsize;
27 u8 version;
28 u8 flags;
29
30 switch (subtype) {
31 case MPTCPOPT_MP_CAPABLE:
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)
45 break;
46
47 /* try to be gentle vs future versions on the initial syn */
48 version = *ptr++ & MPTCP_VERSION_MASK;
49 if (opsize != TCPOLEN_MPTCP_MPC_SYN) {
50 if (version != MPTCP_SUPPORTED_VERSION)
51 break;
52 } else if (version < MPTCP_SUPPORTED_VERSION) {
53 break;
54 }
55
56 flags = *ptr++;
57 if (!mptcp_cap_flag_sha256(flags) ||
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;
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) {
83 mp_opt->rcvr_key = get_unaligned_be64(ptr);
84 ptr += 8;
85 }
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);
101 break;
102
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
135 case MPTCPOPT_DSS:
136 pr_debug("DSS");
137 ptr++;
138
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;
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
181 mp_opt->dss = 1;
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
215 break;
216
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;
244 mp_opt->addr_id = *ptr++;
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 }
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);
272 break;
273
274 case MPTCPOPT_RM_ADDR:
275 if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
276 break;
277
278 ptr++;
279
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
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
295 default:
296 break;
297 }
298 }
299
300 void mptcp_get_options(const struct sk_buff *skb,
301 struct mptcp_options_received *mp_opt)
302 {
303 const struct tcphdr *th = tcp_hdr(skb);
304 const unsigned char *ptr;
305 int length;
306
307 /* initialize option status */
308 mp_opt->mp_capable = 0;
309 mp_opt->mp_join = 0;
310 mp_opt->add_addr = 0;
311 mp_opt->ahmac = 0;
312 mp_opt->fastclose = 0;
313 mp_opt->port = 0;
314 mp_opt->rm_addr = 0;
315 mp_opt->dss = 0;
316
317 length = (th->doff * 4) - sizeof(struct tcphdr);
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)
337 mptcp_parse_option(skb, ptr, opsize, mp_opt);
338 ptr += opsize - 2;
339 length -= opsize;
340 }
341 }
342 }
343
344 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
345 unsigned int *size, struct mptcp_out_options *opts)
346 {
347 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
348
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;
353 if (subflow->request_mptcp) {
354 opts->suboptions = OPTION_MPTCP_MPC_SYN;
355 *size = TCPOLEN_MPTCP_MPC_SYN;
356 return true;
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;
367 }
368 return false;
369 }
370
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
403 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
404 unsigned int *size,
405 unsigned int remaining,
406 struct mptcp_out_options *opts)
407 {
408 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
409 struct mptcp_ext *mpext;
410 unsigned int data_len;
411
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;
420
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) {
427 mpext = mptcp_get_ext(skb);
428 data_len = mpext ? mpext->data_len : 0;
429
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;
435 opts->suboptions = OPTION_MPTCP_MPC_ACK;
436 opts->sndr_key = subflow->local_key;
437 opts->rcvr_key = subflow->remote_key;
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
453 return true;
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;
462 }
463 return false;
464 }
465
466 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
467 struct sk_buff *skb, struct mptcp_ext *ext)
468 {
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;
473
474 if (!ext->use_map || !skb->len) {
475 /* RFC6824 requires a DSS mapping with specific values
476 * if DATA_FIN is set but no data payload is mapped
477 */
478 ext->data_fin = 1;
479 ext->use_map = 1;
480 ext->dsn64 = 1;
481 ext->data_seq = data_fin_tx_seq;
482 ext->subflow_seq = 0;
483 ext->data_len = 1;
484 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
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.
488 */
489 ext->data_fin = 1;
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);
500 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
501 unsigned int dss_size = 0;
502 u64 snd_data_fin_enable;
503 struct mptcp_ext *mpext;
504 unsigned int ack_size;
505 bool ret = false;
506
507 mpext = skb ? mptcp_get_ext(skb) : NULL;
508 snd_data_fin_enable = mptcp_data_fin_enabled(msk);
509
510 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
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
520 if (skb && snd_data_fin_enable)
521 mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
522 ret = true;
523 }
524
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 */
528 opts->ext_copy.use_ack = 0;
529 if (!READ_ONCE(msk->can_ack)) {
530 *size = ALIGN(dss_size, 4);
531 return ret;
532 }
533
534 if (READ_ONCE(msk->use_64bit_ack)) {
535 ack_size = TCPOLEN_MPTCP_DSS_ACK64;
536 opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
537 opts->ext_copy.ack64 = 1;
538 } else {
539 ack_size = TCPOLEN_MPTCP_DSS_ACK32;
540 opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
541 opts->ext_copy.ack64 = 0;
542 }
543 opts->ext_copy.use_ack = 1;
544 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk));
545
546 /* Add kind/length/subtype/flag overhead if mapping is not populated */
547 if (dss_size == 0)
548 ack_size += TCPOLEN_MPTCP_DSS_BASE;
549
550 dss_size += ack_size;
551
552 *size = ALIGN(dss_size, 4);
553 return true;
554 }
555
556 static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id,
557 struct in_addr *addr)
558 {
559 u8 hmac[SHA256_DIGEST_SIZE];
560 u8 msg[7];
561
562 msg[0] = addr_id;
563 memcpy(&msg[1], &addr->s_addr, 4);
564 msg[5] = 0;
565 msg[6] = 0;
566
567 mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);
568
569 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
570 }
571
572 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
573 static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
574 struct in6_addr *addr)
575 {
576 u8 hmac[SHA256_DIGEST_SIZE];
577 u8 msg[19];
578
579 msg[0] = addr_id;
580 memcpy(&msg[1], &addr->s6_addr, 16);
581 msg[17] = 0;
582 msg[18] = 0;
583
584 mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);
585
586 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
587 }
588 #endif
589
590 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb,
591 unsigned int *size,
592 unsigned int remaining,
593 struct mptcp_out_options *opts)
594 {
595 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
596 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
597 bool drop_other_suboptions = false;
598 unsigned int opt_size = *size;
599 struct mptcp_addr_info saddr;
600 bool echo;
601 bool port;
602 int len;
603
604 if ((mptcp_pm_should_add_signal_ipv6(msk) ||
605 mptcp_pm_should_add_signal_port(msk)) &&
606 skb && skb_is_tcp_pure_ack(skb)) {
607 pr_debug("drop other suboptions");
608 opts->suboptions = 0;
609 opts->ext_copy.use_ack = 0;
610 opts->ext_copy.use_map = 0;
611 remaining += opt_size;
612 drop_other_suboptions = true;
613 }
614
615 if (!mptcp_pm_should_add_signal(msk) ||
616 !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port)))
617 return false;
618
619 len = mptcp_add_addr_len(saddr.family, echo, port);
620 if (remaining < len)
621 return false;
622
623 *size = len;
624 if (drop_other_suboptions)
625 *size -= opt_size;
626 opts->addr_id = saddr.id;
627 if (port)
628 opts->port = ntohs(saddr.port);
629 if (saddr.family == AF_INET) {
630 opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
631 opts->addr = saddr.addr;
632 if (!echo) {
633 opts->ahmac = add_addr_generate_hmac(msk->local_key,
634 msk->remote_key,
635 opts->addr_id,
636 &opts->addr);
637 }
638 }
639 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
640 else if (saddr.family == AF_INET6) {
641 opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
642 opts->addr6 = saddr.addr6;
643 if (!echo) {
644 opts->ahmac = add_addr6_generate_hmac(msk->local_key,
645 msk->remote_key,
646 opts->addr_id,
647 &opts->addr6);
648 }
649 }
650 #endif
651 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
652 opts->addr_id, opts->ahmac, echo, opts->port);
653
654 return true;
655 }
656
657 static bool mptcp_established_options_rm_addr(struct sock *sk,
658 unsigned int *size,
659 unsigned int remaining,
660 struct mptcp_out_options *opts)
661 {
662 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
663 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
664 u8 rm_id;
665
666 if (!mptcp_pm_should_rm_signal(msk) ||
667 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id)))
668 return false;
669
670 if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
671 return false;
672
673 *size = TCPOLEN_MPTCP_RM_ADDR_BASE;
674 opts->suboptions |= OPTION_MPTCP_RM_ADDR;
675 opts->rm_id = rm_id;
676
677 pr_debug("rm_id=%d", opts->rm_id);
678
679 return true;
680 }
681
682 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
683 unsigned int *size, unsigned int remaining,
684 struct mptcp_out_options *opts)
685 {
686 unsigned int opt_size = 0;
687 bool ret = false;
688
689 opts->suboptions = 0;
690
691 if (unlikely(mptcp_check_fallback(sk)))
692 return false;
693
694 /* prevent adding of any MPTCP related options on reset packet
695 * until we support MP_TCPRST/MP_FASTCLOSE
696 */
697 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
698 return false;
699
700 if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
701 ret = true;
702 else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
703 opts))
704 ret = true;
705
706 /* we reserved enough space for the above options, and exceeding the
707 * TCP option space would be fatal
708 */
709 if (WARN_ON_ONCE(opt_size > remaining))
710 return false;
711
712 *size += opt_size;
713 remaining -= opt_size;
714 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
715 *size += opt_size;
716 remaining -= opt_size;
717 ret = true;
718 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
719 *size += opt_size;
720 remaining -= opt_size;
721 ret = true;
722 }
723
724 return ret;
725 }
726
727 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
728 struct mptcp_out_options *opts)
729 {
730 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
731
732 if (subflow_req->mp_capable) {
733 opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
734 opts->sndr_key = subflow_req->local_key;
735 *size = TCPOLEN_MPTCP_MPC_SYNACK;
736 pr_debug("subflow_req=%p, local_key=%llu",
737 subflow_req, subflow_req->local_key);
738 return true;
739 } else if (subflow_req->mp_join) {
740 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
741 opts->backup = subflow_req->backup;
742 opts->join_id = subflow_req->local_id;
743 opts->thmac = subflow_req->thmac;
744 opts->nonce = subflow_req->local_nonce;
745 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
746 subflow_req, opts->backup, opts->join_id,
747 opts->thmac, opts->nonce);
748 *size = TCPOLEN_MPTCP_MPJ_SYNACK;
749 return true;
750 }
751 return false;
752 }
753
754 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
755 struct mptcp_subflow_context *subflow,
756 struct sk_buff *skb,
757 struct mptcp_options_received *mp_opt)
758 {
759 /* here we can process OoO, in-window pkts, only in-sequence 4th ack
760 * will make the subflow fully established
761 */
762 if (likely(subflow->fully_established)) {
763 /* on passive sockets, check for 3rd ack retransmission
764 * note that msk is always set by subflow_syn_recv_sock()
765 * for mp_join subflows
766 */
767 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
768 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
769 subflow->mp_join && mp_opt->mp_join &&
770 READ_ONCE(msk->pm.server_side))
771 tcp_send_ack(ssk);
772 goto fully_established;
773 }
774
775 /* we must process OoO packets before the first subflow is fully
776 * established. OoO packets are instead a protocol violation
777 * for MP_JOIN subflows as the peer must not send any data
778 * before receiving the forth ack - cfr. RFC 8684 section 3.2.
779 */
780 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
781 if (subflow->mp_join)
782 goto reset;
783 return subflow->mp_capable;
784 }
785
786 if (mp_opt->dss && mp_opt->use_ack) {
787 /* subflows are fully established as soon as we get any
788 * additional ack.
789 */
790 subflow->fully_established = 1;
791 WRITE_ONCE(msk->fully_established, true);
792 goto fully_established;
793 }
794
795 if (mp_opt->add_addr) {
796 WRITE_ONCE(msk->fully_established, true);
797 return true;
798 }
799
800 /* If the first established packet does not contain MP_CAPABLE + data
801 * then fallback to TCP. Fallback scenarios requires a reset for
802 * MP_JOIN subflows.
803 */
804 if (!mp_opt->mp_capable) {
805 if (subflow->mp_join)
806 goto reset;
807 subflow->mp_capable = 0;
808 pr_fallback(msk);
809 __mptcp_do_fallback(msk);
810 return false;
811 }
812
813 if (unlikely(!READ_ONCE(msk->pm.server_side)))
814 pr_warn_once("bogus mpc option on established client sk");
815 mptcp_subflow_fully_established(subflow, mp_opt);
816
817 fully_established:
818 /* if the subflow is not already linked into the conn_list, we can't
819 * notify the PM: this subflow is still on the listener queue
820 * and the PM possibly acquiring the subflow lock could race with
821 * the listener close
822 */
823 if (likely(subflow->pm_notified) || list_empty(&subflow->node))
824 return true;
825
826 subflow->pm_notified = 1;
827 if (subflow->mp_join) {
828 clear_3rdack_retransmission(ssk);
829 mptcp_pm_subflow_established(msk, subflow);
830 } else {
831 mptcp_pm_fully_established(msk);
832 }
833 return true;
834
835 reset:
836 mptcp_subflow_reset(ssk);
837 return false;
838 }
839
840 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
841 {
842 u32 old_ack32, cur_ack32;
843
844 if (use_64bit)
845 return cur_ack;
846
847 old_ack32 = (u32)old_ack;
848 cur_ack32 = (u32)cur_ack;
849 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
850 if (unlikely(before(cur_ack32, old_ack32)))
851 return cur_ack + (1LL << 32);
852 return cur_ack;
853 }
854
855 static void ack_update_msk(struct mptcp_sock *msk,
856 struct sock *ssk,
857 struct mptcp_options_received *mp_opt)
858 {
859 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt);
860 struct sock *sk = (struct sock *)msk;
861 u64 old_snd_una;
862
863 mptcp_data_lock(sk);
864
865 /* avoid ack expansion on update conflict, to reduce the risk of
866 * wrongly expanding to a future ack sequence number, which is way
867 * more dangerous than missing an ack
868 */
869 old_snd_una = msk->snd_una;
870 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
871
872 /* ACK for data not even sent yet? Ignore. */
873 if (after64(new_snd_una, snd_nxt))
874 new_snd_una = old_snd_una;
875
876 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
877
878 if (after64(new_wnd_end, msk->wnd_end))
879 msk->wnd_end = new_wnd_end;
880
881 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
882 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)) &&
883 sk_stream_memory_free(ssk))
884 __mptcp_check_push(sk, ssk);
885
886 if (after64(new_snd_una, old_snd_una)) {
887 msk->snd_una = new_snd_una;
888 __mptcp_data_acked(sk);
889 }
890 mptcp_data_unlock(sk);
891 }
892
893 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
894 {
895 /* Skip if DATA_FIN was already received.
896 * If updating simultaneously with the recvmsg loop, values
897 * should match. If they mismatch, the peer is misbehaving and
898 * we will prefer the most recent information.
899 */
900 if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))
901 return false;
902
903 WRITE_ONCE(msk->rcv_data_fin_seq,
904 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
905 WRITE_ONCE(msk->rcv_data_fin, 1);
906
907 return true;
908 }
909
910 static bool add_addr_hmac_valid(struct mptcp_sock *msk,
911 struct mptcp_options_received *mp_opt)
912 {
913 u64 hmac = 0;
914
915 if (mp_opt->echo)
916 return true;
917
918 if (mp_opt->family == MPTCP_ADDR_IPVERSION_4)
919 hmac = add_addr_generate_hmac(msk->remote_key,
920 msk->local_key,
921 mp_opt->addr_id, &mp_opt->addr);
922 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
923 else
924 hmac = add_addr6_generate_hmac(msk->remote_key,
925 msk->local_key,
926 mp_opt->addr_id, &mp_opt->addr6);
927 #endif
928
929 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
930 msk, (unsigned long long)hmac,
931 (unsigned long long)mp_opt->ahmac);
932
933 return hmac == mp_opt->ahmac;
934 }
935
936 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
937 {
938 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
939 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
940 struct mptcp_options_received mp_opt;
941 struct mptcp_ext *mpext;
942
943 if (__mptcp_check_fallback(msk)) {
944 /* Keep it simple and unconditionally trigger send data cleanup and
945 * pending queue spooling. We will need to acquire the data lock
946 * for more accurate checks, and once the lock is acquired, such
947 * helpers are cheap.
948 */
949 mptcp_data_lock(subflow->conn);
950 if (sk_stream_memory_free(sk))
951 __mptcp_check_push(subflow->conn, sk);
952 __mptcp_data_acked(subflow->conn);
953 mptcp_data_unlock(subflow->conn);
954 return;
955 }
956
957 mptcp_get_options(skb, &mp_opt);
958 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
959 return;
960
961 if (mp_opt.fastclose &&
962 msk->local_key == mp_opt.rcvr_key) {
963 WRITE_ONCE(msk->rcv_fastclose, true);
964 mptcp_schedule_work((struct sock *)msk);
965 }
966
967 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) {
968 struct mptcp_addr_info addr;
969
970 addr.port = htons(mp_opt.port);
971 addr.id = mp_opt.addr_id;
972 if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) {
973 addr.family = AF_INET;
974 addr.addr = mp_opt.addr;
975 }
976 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
977 else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) {
978 addr.family = AF_INET6;
979 addr.addr6 = mp_opt.addr6;
980 }
981 #endif
982 if (!mp_opt.echo) {
983 mptcp_pm_add_addr_received(msk, &addr);
984 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
985 } else {
986 mptcp_pm_del_add_timer(msk, &addr);
987 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
988 }
989 mp_opt.add_addr = 0;
990 }
991
992 if (mp_opt.rm_addr) {
993 mptcp_pm_rm_addr_received(msk, mp_opt.rm_id);
994 mp_opt.rm_addr = 0;
995 }
996
997 if (!mp_opt.dss)
998 return;
999
1000 /* we can't wait for recvmsg() to update the ack_seq, otherwise
1001 * monodirectional flows will stuck
1002 */
1003 if (mp_opt.use_ack)
1004 ack_update_msk(msk, sk, &mp_opt);
1005
1006 /* Zero-data-length packets are dropped by the caller and not
1007 * propagated to the MPTCP layer, so the skb extension does not
1008 * need to be allocated or populated. DATA_FIN information, if
1009 * present, needs to be updated here before the skb is freed.
1010 */
1011 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
1012 if (mp_opt.data_fin && mp_opt.data_len == 1 &&
1013 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
1014 schedule_work(&msk->work))
1015 sock_hold(subflow->conn);
1016
1017 return;
1018 }
1019
1020 mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
1021 if (!mpext)
1022 return;
1023
1024 memset(mpext, 0, sizeof(*mpext));
1025
1026 if (mp_opt.use_map) {
1027 if (mp_opt.mpc_map) {
1028 /* this is an MP_CAPABLE carrying MPTCP data
1029 * we know this map the first chunk of data
1030 */
1031 mptcp_crypto_key_sha(subflow->remote_key, NULL,
1032 &mpext->data_seq);
1033 mpext->data_seq++;
1034 mpext->subflow_seq = 1;
1035 mpext->dsn64 = 1;
1036 mpext->mpc_map = 1;
1037 mpext->data_fin = 0;
1038 } else {
1039 mpext->data_seq = mp_opt.data_seq;
1040 mpext->subflow_seq = mp_opt.subflow_seq;
1041 mpext->dsn64 = mp_opt.dsn64;
1042 mpext->data_fin = mp_opt.data_fin;
1043 }
1044 mpext->data_len = mp_opt.data_len;
1045 mpext->use_map = 1;
1046 }
1047 }
1048
1049 static void mptcp_set_rwin(const struct tcp_sock *tp)
1050 {
1051 const struct sock *ssk = (const struct sock *)tp;
1052 const struct mptcp_subflow_context *subflow;
1053 struct mptcp_sock *msk;
1054 u64 ack_seq;
1055
1056 subflow = mptcp_subflow_ctx(ssk);
1057 msk = mptcp_sk(subflow->conn);
1058
1059 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd;
1060
1061 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent)))
1062 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
1063 }
1064
1065 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
1066 struct mptcp_out_options *opts)
1067 {
1068 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK |
1069 OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
1070 u8 len;
1071
1072 if (OPTION_MPTCP_MPC_SYN & opts->suboptions)
1073 len = TCPOLEN_MPTCP_MPC_SYN;
1074 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions)
1075 len = TCPOLEN_MPTCP_MPC_SYNACK;
1076 else if (opts->ext_copy.data_len)
1077 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
1078 else
1079 len = TCPOLEN_MPTCP_MPC_ACK;
1080
1081 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
1082 MPTCP_SUPPORTED_VERSION,
1083 MPTCP_CAP_HMAC_SHA256);
1084
1085 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
1086 opts->suboptions))
1087 goto mp_capable_done;
1088
1089 put_unaligned_be64(opts->sndr_key, ptr);
1090 ptr += 2;
1091 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
1092 goto mp_capable_done;
1093
1094 put_unaligned_be64(opts->rcvr_key, ptr);
1095 ptr += 2;
1096 if (!opts->ext_copy.data_len)
1097 goto mp_capable_done;
1098
1099 put_unaligned_be32(opts->ext_copy.data_len << 16 |
1100 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1101 ptr += 1;
1102 }
1103
1104 mp_capable_done:
1105 if ((OPTION_MPTCP_ADD_ADDR
1106 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1107 | OPTION_MPTCP_ADD_ADDR6
1108 #endif
1109 ) & opts->suboptions) {
1110 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1111 u8 echo = MPTCP_ADDR_ECHO;
1112
1113 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1114 if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions)
1115 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1116 #endif
1117
1118 if (opts->port)
1119 len += TCPOLEN_MPTCP_PORT_LEN;
1120
1121 if (opts->ahmac) {
1122 len += sizeof(opts->ahmac);
1123 echo = 0;
1124 }
1125
1126 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1127 len, echo, opts->addr_id);
1128 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
1129 memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
1130 ptr += 1;
1131 }
1132 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1133 else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
1134 memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
1135 ptr += 4;
1136 }
1137 #endif
1138
1139 if (!opts->port) {
1140 if (opts->ahmac) {
1141 put_unaligned_be64(opts->ahmac, ptr);
1142 ptr += 2;
1143 }
1144 } else {
1145 if (opts->ahmac) {
1146 u8 *bptr = (u8 *)ptr;
1147
1148 put_unaligned_be16(opts->port, bptr);
1149 bptr += 2;
1150 put_unaligned_be64(opts->ahmac, bptr);
1151 bptr += 8;
1152 put_unaligned_be16(TCPOPT_NOP << 8 |
1153 TCPOPT_NOP, bptr);
1154
1155 ptr += 3;
1156 } else {
1157 put_unaligned_be32(opts->port << 16 |
1158 TCPOPT_NOP << 8 |
1159 TCPOPT_NOP, ptr);
1160 ptr += 1;
1161 }
1162 }
1163 }
1164
1165 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
1166 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
1167 TCPOLEN_MPTCP_RM_ADDR_BASE,
1168 0, opts->rm_id);
1169 }
1170
1171 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
1172 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1173 TCPOLEN_MPTCP_MPJ_SYN,
1174 opts->backup, opts->join_id);
1175 put_unaligned_be32(opts->token, ptr);
1176 ptr += 1;
1177 put_unaligned_be32(opts->nonce, ptr);
1178 ptr += 1;
1179 }
1180
1181 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
1182 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1183 TCPOLEN_MPTCP_MPJ_SYNACK,
1184 opts->backup, opts->join_id);
1185 put_unaligned_be64(opts->thmac, ptr);
1186 ptr += 2;
1187 put_unaligned_be32(opts->nonce, ptr);
1188 ptr += 1;
1189 }
1190
1191 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
1192 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1193 TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
1194 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
1195 ptr += 5;
1196 }
1197
1198 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
1199 struct mptcp_ext *mpext = &opts->ext_copy;
1200 u8 len = TCPOLEN_MPTCP_DSS_BASE;
1201 u8 flags = 0;
1202
1203 if (mpext->use_ack) {
1204 flags = MPTCP_DSS_HAS_ACK;
1205 if (mpext->ack64) {
1206 len += TCPOLEN_MPTCP_DSS_ACK64;
1207 flags |= MPTCP_DSS_ACK64;
1208 } else {
1209 len += TCPOLEN_MPTCP_DSS_ACK32;
1210 }
1211 }
1212
1213 if (mpext->use_map) {
1214 len += TCPOLEN_MPTCP_DSS_MAP64;
1215
1216 /* Use only 64-bit mapping flags for now, add
1217 * support for optional 32-bit mappings later.
1218 */
1219 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
1220 if (mpext->data_fin)
1221 flags |= MPTCP_DSS_DATA_FIN;
1222 }
1223
1224 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
1225
1226 if (mpext->use_ack) {
1227 if (mpext->ack64) {
1228 put_unaligned_be64(mpext->data_ack, ptr);
1229 ptr += 2;
1230 } else {
1231 put_unaligned_be32(mpext->data_ack32, ptr);
1232 ptr += 1;
1233 }
1234 }
1235
1236 if (mpext->use_map) {
1237 put_unaligned_be64(mpext->data_seq, ptr);
1238 ptr += 2;
1239 put_unaligned_be32(mpext->subflow_seq, ptr);
1240 ptr += 1;
1241 put_unaligned_be32(mpext->data_len << 16 |
1242 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1243 }
1244 }
1245
1246 if (tp)
1247 mptcp_set_rwin(tp);
1248 }
Linux with added FPC-III support