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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 | ||
7 | #include <linux/kernel.h> | |
8 | #include <net/tcp.h> | |
9 | #include <net/mptcp.h> | |
10 | #include "protocol.h" | |
11 | ||
65492c5a PA |
12 | static bool mptcp_cap_flag_sha256(u8 flags) |
13 | { | |
14 | return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; | |
15 | } | |
16 | ||
cc7972ea CP |
17 | void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr, |
18 | int opsize, struct tcp_options_received *opt_rx) | |
eda7acdd PK |
19 | { |
20 | struct mptcp_options_received *mp_opt = &opt_rx->mptcp; | |
21 | u8 subtype = *ptr >> 4; | |
648ef4b8 | 22 | int expected_opsize; |
eda7acdd PK |
23 | u8 version; |
24 | u8 flags; | |
25 | ||
26 | switch (subtype) { | |
27 | case MPTCPOPT_MP_CAPABLE: | |
cc7972ea CP |
28 | /* strict size checking */ |
29 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { | |
30 | if (skb->len > tcp_hdr(skb)->doff << 2) | |
31 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
32 | else | |
33 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK; | |
34 | } else { | |
35 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) | |
36 | expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; | |
37 | else | |
38 | expected_opsize = TCPOLEN_MPTCP_MPC_SYN; | |
39 | } | |
40 | if (opsize != expected_opsize) | |
eda7acdd PK |
41 | break; |
42 | ||
cc7972ea | 43 | /* try to be gentle vs future versions on the initial syn */ |
eda7acdd | 44 | version = *ptr++ & MPTCP_VERSION_MASK; |
cc7972ea CP |
45 | if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
46 | if (version != MPTCP_SUPPORTED_VERSION) | |
47 | break; | |
48 | } else if (version < MPTCP_SUPPORTED_VERSION) { | |
eda7acdd | 49 | break; |
cc7972ea | 50 | } |
eda7acdd PK |
51 | |
52 | flags = *ptr++; | |
65492c5a | 53 | if (!mptcp_cap_flag_sha256(flags) || |
eda7acdd PK |
54 | (flags & MPTCP_CAP_EXTENSIBILITY)) |
55 | break; | |
56 | ||
57 | /* RFC 6824, Section 3.1: | |
58 | * "For the Checksum Required bit (labeled "A"), if either | |
59 | * host requires the use of checksums, checksums MUST be used. | |
60 | * In other words, the only way for checksums not to be used | |
61 | * is if both hosts in their SYNs set A=0." | |
62 | * | |
63 | * Section 3.3.0: | |
64 | * "If a checksum is not present when its use has been | |
65 | * negotiated, the receiver MUST close the subflow with a RST as | |
66 | * it is considered broken." | |
67 | * | |
68 | * We don't implement DSS checksum - fall back to TCP. | |
69 | */ | |
70 | if (flags & MPTCP_CAP_CHECKSUM_REQD) | |
71 | break; | |
72 | ||
73 | mp_opt->mp_capable = 1; | |
cc7972ea CP |
74 | if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
75 | mp_opt->sndr_key = get_unaligned_be64(ptr); | |
76 | ptr += 8; | |
77 | } | |
78 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { | |
eda7acdd PK |
79 | mp_opt->rcvr_key = get_unaligned_be64(ptr); |
80 | ptr += 8; | |
eda7acdd | 81 | } |
cc7972ea CP |
82 | if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) { |
83 | /* Section 3.1.: | |
84 | * "the data parameters in a MP_CAPABLE are semantically | |
85 | * equivalent to those in a DSS option and can be used | |
86 | * interchangeably." | |
87 | */ | |
88 | mp_opt->dss = 1; | |
89 | mp_opt->use_map = 1; | |
90 | mp_opt->mpc_map = 1; | |
91 | mp_opt->data_len = get_unaligned_be16(ptr); | |
92 | ptr += 2; | |
93 | } | |
94 | pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d", | |
95 | version, flags, opsize, mp_opt->sndr_key, | |
96 | mp_opt->rcvr_key, mp_opt->data_len); | |
eda7acdd PK |
97 | break; |
98 | ||
99 | case MPTCPOPT_DSS: | |
100 | pr_debug("DSS"); | |
648ef4b8 MM |
101 | ptr++; |
102 | ||
cc7972ea CP |
103 | /* we must clear 'mpc_map' be able to detect MP_CAPABLE |
104 | * map vs DSS map in mptcp_incoming_options(), and reconstruct | |
105 | * map info accordingly | |
106 | */ | |
107 | mp_opt->mpc_map = 0; | |
648ef4b8 MM |
108 | flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
109 | mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; | |
110 | mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; | |
111 | mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; | |
112 | mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; | |
113 | mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); | |
114 | ||
115 | pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", | |
116 | mp_opt->data_fin, mp_opt->dsn64, | |
117 | mp_opt->use_map, mp_opt->ack64, | |
118 | mp_opt->use_ack); | |
119 | ||
120 | expected_opsize = TCPOLEN_MPTCP_DSS_BASE; | |
121 | ||
122 | if (mp_opt->use_ack) { | |
123 | if (mp_opt->ack64) | |
124 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; | |
125 | else | |
126 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; | |
127 | } | |
128 | ||
129 | if (mp_opt->use_map) { | |
130 | if (mp_opt->dsn64) | |
131 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; | |
132 | else | |
133 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; | |
134 | } | |
135 | ||
136 | /* RFC 6824, Section 3.3: | |
137 | * If a checksum is present, but its use had | |
138 | * not been negotiated in the MP_CAPABLE handshake, | |
139 | * the checksum field MUST be ignored. | |
140 | */ | |
141 | if (opsize != expected_opsize && | |
142 | opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) | |
143 | break; | |
144 | ||
eda7acdd | 145 | mp_opt->dss = 1; |
648ef4b8 MM |
146 | |
147 | if (mp_opt->use_ack) { | |
148 | if (mp_opt->ack64) { | |
149 | mp_opt->data_ack = get_unaligned_be64(ptr); | |
150 | ptr += 8; | |
151 | } else { | |
152 | mp_opt->data_ack = get_unaligned_be32(ptr); | |
153 | ptr += 4; | |
154 | } | |
155 | ||
156 | pr_debug("data_ack=%llu", mp_opt->data_ack); | |
157 | } | |
158 | ||
159 | if (mp_opt->use_map) { | |
160 | if (mp_opt->dsn64) { | |
161 | mp_opt->data_seq = get_unaligned_be64(ptr); | |
162 | ptr += 8; | |
163 | } else { | |
164 | mp_opt->data_seq = get_unaligned_be32(ptr); | |
165 | ptr += 4; | |
166 | } | |
167 | ||
168 | mp_opt->subflow_seq = get_unaligned_be32(ptr); | |
169 | ptr += 4; | |
170 | ||
171 | mp_opt->data_len = get_unaligned_be16(ptr); | |
172 | ptr += 2; | |
173 | ||
174 | pr_debug("data_seq=%llu subflow_seq=%u data_len=%u", | |
175 | mp_opt->data_seq, mp_opt->subflow_seq, | |
176 | mp_opt->data_len); | |
177 | } | |
178 | ||
eda7acdd PK |
179 | break; |
180 | ||
181 | default: | |
182 | break; | |
183 | } | |
184 | } | |
185 | ||
cec37a6e PK |
186 | void mptcp_get_options(const struct sk_buff *skb, |
187 | struct tcp_options_received *opt_rx) | |
188 | { | |
189 | const unsigned char *ptr; | |
190 | const struct tcphdr *th = tcp_hdr(skb); | |
191 | int length = (th->doff * 4) - sizeof(struct tcphdr); | |
192 | ||
193 | ptr = (const unsigned char *)(th + 1); | |
194 | ||
195 | while (length > 0) { | |
196 | int opcode = *ptr++; | |
197 | int opsize; | |
198 | ||
199 | switch (opcode) { | |
200 | case TCPOPT_EOL: | |
201 | return; | |
202 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
203 | length--; | |
204 | continue; | |
205 | default: | |
206 | opsize = *ptr++; | |
207 | if (opsize < 2) /* "silly options" */ | |
208 | return; | |
209 | if (opsize > length) | |
210 | return; /* don't parse partial options */ | |
211 | if (opcode == TCPOPT_MPTCP) | |
cc7972ea | 212 | mptcp_parse_option(skb, ptr, opsize, opt_rx); |
cec37a6e PK |
213 | ptr += opsize - 2; |
214 | length -= opsize; | |
215 | } | |
216 | } | |
217 | } | |
218 | ||
cc7972ea CP |
219 | bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
220 | unsigned int *size, struct mptcp_out_options *opts) | |
cec37a6e PK |
221 | { |
222 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
223 | ||
cc7972ea CP |
224 | /* we will use snd_isn to detect first pkt [re]transmission |
225 | * in mptcp_established_options_mp() | |
226 | */ | |
227 | subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; | |
cec37a6e PK |
228 | if (subflow->request_mptcp) { |
229 | pr_debug("local_key=%llu", subflow->local_key); | |
230 | opts->suboptions = OPTION_MPTCP_MPC_SYN; | |
231 | opts->sndr_key = subflow->local_key; | |
232 | *size = TCPOLEN_MPTCP_MPC_SYN; | |
233 | return true; | |
234 | } | |
235 | return false; | |
236 | } | |
237 | ||
238 | void mptcp_rcv_synsent(struct sock *sk) | |
239 | { | |
240 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
241 | struct tcp_sock *tp = tcp_sk(sk); | |
242 | ||
243 | pr_debug("subflow=%p", subflow); | |
244 | if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) { | |
245 | subflow->mp_capable = 1; | |
246 | subflow->remote_key = tp->rx_opt.mptcp.sndr_key; | |
247 | } else { | |
248 | tcp_sk(sk)->is_mptcp = 0; | |
249 | } | |
250 | } | |
251 | ||
cc7972ea CP |
252 | static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
253 | unsigned int *size, | |
6d0060f6 MM |
254 | unsigned int remaining, |
255 | struct mptcp_out_options *opts) | |
cec37a6e PK |
256 | { |
257 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
cc7972ea CP |
258 | struct mptcp_ext *mpext; |
259 | unsigned int data_len; | |
260 | ||
261 | pr_debug("subflow=%p fourth_ack=%d seq=%x:%x remaining=%d", subflow, | |
262 | subflow->fourth_ack, subflow->snd_isn, | |
263 | skb ? TCP_SKB_CB(skb)->seq : 0, remaining); | |
264 | ||
265 | if (subflow->mp_capable && !subflow->fourth_ack && skb && | |
266 | subflow->snd_isn == TCP_SKB_CB(skb)->seq) { | |
267 | /* When skb is not available, we better over-estimate the | |
268 | * emitted options len. A full DSS option is longer than | |
269 | * TCPOLEN_MPTCP_MPC_ACK_DATA, so let's the caller try to fit | |
270 | * that. | |
271 | */ | |
272 | mpext = mptcp_get_ext(skb); | |
273 | data_len = mpext ? mpext->data_len : 0; | |
cec37a6e | 274 | |
cc7972ea CP |
275 | /* we will check ext_copy.data_len in mptcp_write_options() to |
276 | * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and | |
277 | * TCPOLEN_MPTCP_MPC_ACK | |
278 | */ | |
279 | opts->ext_copy.data_len = data_len; | |
cec37a6e PK |
280 | opts->suboptions = OPTION_MPTCP_MPC_ACK; |
281 | opts->sndr_key = subflow->local_key; | |
282 | opts->rcvr_key = subflow->remote_key; | |
cc7972ea CP |
283 | |
284 | /* Section 3.1. | |
285 | * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK | |
286 | * packets that start the first subflow of an MPTCP connection, | |
287 | * as well as the first packet that carries data | |
288 | */ | |
289 | if (data_len > 0) | |
290 | *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); | |
291 | else | |
292 | *size = TCPOLEN_MPTCP_MPC_ACK; | |
293 | ||
294 | pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", | |
295 | subflow, subflow->local_key, subflow->remote_key, | |
296 | data_len); | |
297 | ||
cec37a6e PK |
298 | return true; |
299 | } | |
300 | return false; | |
301 | } | |
302 | ||
6d0060f6 MM |
303 | static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
304 | struct mptcp_ext *ext) | |
305 | { | |
306 | ext->data_fin = 1; | |
307 | ||
308 | if (!ext->use_map) { | |
309 | /* RFC6824 requires a DSS mapping with specific values | |
310 | * if DATA_FIN is set but no data payload is mapped | |
311 | */ | |
312 | ext->use_map = 1; | |
313 | ext->dsn64 = 1; | |
314 | ext->data_seq = mptcp_sk(subflow->conn)->write_seq; | |
315 | ext->subflow_seq = 0; | |
316 | ext->data_len = 1; | |
317 | } else { | |
318 | /* If there's an existing DSS mapping, DATA_FIN consumes | |
319 | * 1 additional byte of mapping space. | |
320 | */ | |
321 | ext->data_len++; | |
322 | } | |
323 | } | |
324 | ||
325 | static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, | |
326 | unsigned int *size, | |
327 | unsigned int remaining, | |
328 | struct mptcp_out_options *opts) | |
329 | { | |
330 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); | |
331 | unsigned int dss_size = 0; | |
332 | struct mptcp_ext *mpext; | |
333 | struct mptcp_sock *msk; | |
334 | unsigned int ack_size; | |
335 | u8 tcp_fin; | |
336 | ||
337 | if (skb) { | |
338 | mpext = mptcp_get_ext(skb); | |
339 | tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; | |
340 | } else { | |
341 | mpext = NULL; | |
342 | tcp_fin = 0; | |
343 | } | |
344 | ||
345 | if (!skb || (mpext && mpext->use_map) || tcp_fin) { | |
346 | unsigned int map_size; | |
347 | ||
348 | map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; | |
349 | ||
350 | remaining -= map_size; | |
351 | dss_size = map_size; | |
352 | if (mpext) | |
353 | opts->ext_copy = *mpext; | |
354 | ||
355 | if (skb && tcp_fin && | |
356 | subflow->conn->sk_state != TCP_ESTABLISHED) | |
357 | mptcp_write_data_fin(subflow, &opts->ext_copy); | |
358 | } | |
359 | ||
360 | ack_size = TCPOLEN_MPTCP_DSS_ACK64; | |
361 | ||
362 | /* Add kind/length/subtype/flag overhead if mapping is not populated */ | |
363 | if (dss_size == 0) | |
364 | ack_size += TCPOLEN_MPTCP_DSS_BASE; | |
365 | ||
366 | dss_size += ack_size; | |
367 | ||
368 | msk = mptcp_sk(mptcp_subflow_ctx(sk)->conn); | |
369 | if (msk) { | |
370 | opts->ext_copy.data_ack = msk->ack_seq; | |
371 | } else { | |
372 | mptcp_crypto_key_sha(mptcp_subflow_ctx(sk)->remote_key, | |
373 | NULL, &opts->ext_copy.data_ack); | |
374 | opts->ext_copy.data_ack++; | |
375 | } | |
376 | ||
377 | opts->ext_copy.ack64 = 1; | |
378 | opts->ext_copy.use_ack = 1; | |
379 | ||
380 | *size = ALIGN(dss_size, 4); | |
381 | return true; | |
382 | } | |
383 | ||
384 | bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, | |
385 | unsigned int *size, unsigned int remaining, | |
386 | struct mptcp_out_options *opts) | |
387 | { | |
388 | unsigned int opt_size = 0; | |
389 | bool ret = false; | |
390 | ||
cc7972ea | 391 | if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts)) |
6d0060f6 MM |
392 | ret = true; |
393 | else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining, | |
394 | opts)) | |
395 | ret = true; | |
396 | ||
397 | /* we reserved enough space for the above options, and exceeding the | |
398 | * TCP option space would be fatal | |
399 | */ | |
400 | if (WARN_ON_ONCE(opt_size > remaining)) | |
401 | return false; | |
402 | ||
403 | *size += opt_size; | |
404 | remaining -= opt_size; | |
405 | ||
406 | return ret; | |
407 | } | |
408 | ||
cec37a6e PK |
409 | bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
410 | struct mptcp_out_options *opts) | |
411 | { | |
412 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); | |
413 | ||
414 | if (subflow_req->mp_capable) { | |
415 | opts->suboptions = OPTION_MPTCP_MPC_SYNACK; | |
416 | opts->sndr_key = subflow_req->local_key; | |
417 | *size = TCPOLEN_MPTCP_MPC_SYNACK; | |
418 | pr_debug("subflow_req=%p, local_key=%llu", | |
419 | subflow_req, subflow_req->local_key); | |
420 | return true; | |
421 | } | |
422 | return false; | |
423 | } | |
424 | ||
648ef4b8 MM |
425 | void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb, |
426 | struct tcp_options_received *opt_rx) | |
427 | { | |
428 | struct mptcp_options_received *mp_opt; | |
429 | struct mptcp_ext *mpext; | |
430 | ||
431 | mp_opt = &opt_rx->mptcp; | |
432 | ||
433 | if (!mp_opt->dss) | |
434 | return; | |
435 | ||
436 | mpext = skb_ext_add(skb, SKB_EXT_MPTCP); | |
437 | if (!mpext) | |
438 | return; | |
439 | ||
440 | memset(mpext, 0, sizeof(*mpext)); | |
441 | ||
442 | if (mp_opt->use_map) { | |
cc7972ea CP |
443 | if (mp_opt->mpc_map) { |
444 | struct mptcp_subflow_context *subflow = | |
445 | mptcp_subflow_ctx(sk); | |
446 | ||
447 | /* this is an MP_CAPABLE carrying MPTCP data | |
448 | * we know this map the first chunk of data | |
449 | */ | |
450 | mptcp_crypto_key_sha(subflow->remote_key, NULL, | |
451 | &mpext->data_seq); | |
452 | mpext->data_seq++; | |
453 | mpext->subflow_seq = 1; | |
454 | mpext->dsn64 = 1; | |
455 | mpext->mpc_map = 1; | |
456 | } else { | |
457 | mpext->data_seq = mp_opt->data_seq; | |
458 | mpext->subflow_seq = mp_opt->subflow_seq; | |
459 | mpext->dsn64 = mp_opt->dsn64; | |
460 | } | |
648ef4b8 MM |
461 | mpext->data_len = mp_opt->data_len; |
462 | mpext->use_map = 1; | |
648ef4b8 MM |
463 | } |
464 | ||
465 | if (mp_opt->use_ack) { | |
466 | mpext->data_ack = mp_opt->data_ack; | |
467 | mpext->use_ack = 1; | |
468 | mpext->ack64 = mp_opt->ack64; | |
469 | } | |
470 | ||
471 | mpext->data_fin = mp_opt->data_fin; | |
472 | } | |
473 | ||
eda7acdd PK |
474 | void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts) |
475 | { | |
cc7972ea | 476 | if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | |
eda7acdd PK |
477 | OPTION_MPTCP_MPC_ACK) & opts->suboptions) { |
478 | u8 len; | |
479 | ||
480 | if (OPTION_MPTCP_MPC_SYN & opts->suboptions) | |
481 | len = TCPOLEN_MPTCP_MPC_SYN; | |
cec37a6e PK |
482 | else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) |
483 | len = TCPOLEN_MPTCP_MPC_SYNACK; | |
cc7972ea CP |
484 | else if (opts->ext_copy.data_len) |
485 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; | |
eda7acdd PK |
486 | else |
487 | len = TCPOLEN_MPTCP_MPC_ACK; | |
488 | ||
489 | *ptr++ = htonl((TCPOPT_MPTCP << 24) | (len << 16) | | |
490 | (MPTCPOPT_MP_CAPABLE << 12) | | |
491 | (MPTCP_SUPPORTED_VERSION << 8) | | |
65492c5a | 492 | MPTCP_CAP_HMAC_SHA256); |
cc7972ea CP |
493 | |
494 | if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & | |
495 | opts->suboptions)) | |
496 | goto mp_capable_done; | |
497 | ||
eda7acdd PK |
498 | put_unaligned_be64(opts->sndr_key, ptr); |
499 | ptr += 2; | |
cc7972ea CP |
500 | if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
501 | goto mp_capable_done; | |
502 | ||
503 | put_unaligned_be64(opts->rcvr_key, ptr); | |
504 | ptr += 2; | |
505 | if (!opts->ext_copy.data_len) | |
506 | goto mp_capable_done; | |
507 | ||
508 | put_unaligned_be32(opts->ext_copy.data_len << 16 | | |
509 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
510 | ptr += 1; | |
eda7acdd | 511 | } |
6d0060f6 | 512 | |
cc7972ea | 513 | mp_capable_done: |
6d0060f6 MM |
514 | if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { |
515 | struct mptcp_ext *mpext = &opts->ext_copy; | |
516 | u8 len = TCPOLEN_MPTCP_DSS_BASE; | |
517 | u8 flags = 0; | |
518 | ||
519 | if (mpext->use_ack) { | |
520 | len += TCPOLEN_MPTCP_DSS_ACK64; | |
521 | flags = MPTCP_DSS_HAS_ACK | MPTCP_DSS_ACK64; | |
522 | } | |
523 | ||
524 | if (mpext->use_map) { | |
525 | len += TCPOLEN_MPTCP_DSS_MAP64; | |
526 | ||
527 | /* Use only 64-bit mapping flags for now, add | |
528 | * support for optional 32-bit mappings later. | |
529 | */ | |
530 | flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; | |
531 | if (mpext->data_fin) | |
532 | flags |= MPTCP_DSS_DATA_FIN; | |
533 | } | |
534 | ||
535 | *ptr++ = htonl((TCPOPT_MPTCP << 24) | | |
536 | (len << 16) | | |
537 | (MPTCPOPT_DSS << 12) | | |
538 | (flags)); | |
539 | ||
540 | if (mpext->use_ack) { | |
541 | put_unaligned_be64(mpext->data_ack, ptr); | |
542 | ptr += 2; | |
543 | } | |
544 | ||
545 | if (mpext->use_map) { | |
546 | put_unaligned_be64(mpext->data_seq, ptr); | |
547 | ptr += 2; | |
548 | put_unaligned_be32(mpext->subflow_seq, ptr); | |
549 | ptr += 1; | |
550 | put_unaligned_be32(mpext->data_len << 16 | | |
551 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); | |
552 | } | |
553 | } | |
eda7acdd | 554 | } |