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 | #include <trace/events/mptcp.h> |
17 | |
18 | static bool mptcp_cap_flag_sha256(u8 flags) |
19 | { |
20 | return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; |
21 | } |
22 | |
23 | static void mptcp_parse_option(const struct sk_buff *skb, |
24 | const unsigned char *ptr, int opsize, |
25 | struct mptcp_options_received *mp_opt) |
26 | { |
27 | u8 subtype = *ptr >> 4; |
28 | int expected_opsize; |
29 | u16 subopt; |
30 | u8 version; |
31 | u8 flags; |
32 | u8 i; |
33 | |
34 | switch (subtype) { |
35 | case MPTCPOPT_MP_CAPABLE: |
36 | /* strict size checking */ |
37 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
38 | if (skb->len > tcp_hdr(skb)->doff << 2) |
39 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; |
40 | else |
41 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK; |
42 | subopt = OPTION_MPTCP_MPC_ACK; |
43 | } else { |
44 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) { |
45 | expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; |
46 | subopt = OPTION_MPTCP_MPC_SYNACK; |
47 | } else { |
48 | expected_opsize = TCPOLEN_MPTCP_MPC_SYN; |
49 | subopt = OPTION_MPTCP_MPC_SYN; |
50 | } |
51 | } |
52 | |
53 | /* Cfr RFC 8684 Section 3.3.0: |
54 | * If a checksum is present but its use had |
55 | * not been negotiated in the MP_CAPABLE handshake, the receiver MUST |
56 | * close the subflow with a RST, as it is not behaving as negotiated. |
57 | * If a checksum is not present when its use has been negotiated, the |
58 | * receiver MUST close the subflow with a RST, as it is considered |
59 | * broken |
60 | * We parse even option with mismatching csum presence, so that |
61 | * later in subflow_data_ready we can trigger the reset. |
62 | */ |
63 | if (opsize != expected_opsize && |
64 | (expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA || |
65 | opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM)) |
66 | break; |
67 | |
68 | /* try to be gentle vs future versions on the initial syn */ |
69 | version = *ptr++ & MPTCP_VERSION_MASK; |
70 | if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
71 | if (version != MPTCP_SUPPORTED_VERSION) |
72 | break; |
73 | } else if (version < MPTCP_SUPPORTED_VERSION) { |
74 | break; |
75 | } |
76 | |
77 | flags = *ptr++; |
78 | if (!mptcp_cap_flag_sha256(flags) || |
79 | (flags & MPTCP_CAP_EXTENSIBILITY)) |
80 | break; |
81 | |
82 | /* RFC 6824, Section 3.1: |
83 | * "For the Checksum Required bit (labeled "A"), if either |
84 | * host requires the use of checksums, checksums MUST be used. |
85 | * In other words, the only way for checksums not to be used |
86 | * is if both hosts in their SYNs set A=0." |
87 | */ |
88 | if (flags & MPTCP_CAP_CHECKSUM_REQD) |
89 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
90 | |
91 | mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0); |
92 | |
93 | mp_opt->suboptions |= subopt; |
94 | if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
95 | mp_opt->sndr_key = get_unaligned_be64(p: ptr); |
96 | ptr += 8; |
97 | } |
98 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { |
99 | mp_opt->rcvr_key = get_unaligned_be64(p: ptr); |
100 | ptr += 8; |
101 | } |
102 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) { |
103 | /* Section 3.1.: |
104 | * "the data parameters in a MP_CAPABLE are semantically |
105 | * equivalent to those in a DSS option and can be used |
106 | * interchangeably." |
107 | */ |
108 | mp_opt->suboptions |= OPTION_MPTCP_DSS; |
109 | mp_opt->use_map = 1; |
110 | mp_opt->mpc_map = 1; |
111 | mp_opt->data_len = get_unaligned_be16(p: ptr); |
112 | ptr += 2; |
113 | } |
114 | if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) { |
115 | mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
116 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
117 | ptr += 2; |
118 | } |
119 | pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u" , |
120 | version, flags, opsize, mp_opt->sndr_key, |
121 | mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum); |
122 | break; |
123 | |
124 | case MPTCPOPT_MP_JOIN: |
125 | mp_opt->suboptions |= OPTIONS_MPTCP_MPJ; |
126 | if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { |
127 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
128 | mp_opt->join_id = *ptr++; |
129 | mp_opt->token = get_unaligned_be32(p: ptr); |
130 | ptr += 4; |
131 | mp_opt->nonce = get_unaligned_be32(p: ptr); |
132 | ptr += 4; |
133 | pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u" , |
134 | mp_opt->backup, mp_opt->join_id, |
135 | mp_opt->token, mp_opt->nonce); |
136 | } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { |
137 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
138 | mp_opt->join_id = *ptr++; |
139 | mp_opt->thmac = get_unaligned_be64(p: ptr); |
140 | ptr += 8; |
141 | mp_opt->nonce = get_unaligned_be32(p: ptr); |
142 | ptr += 4; |
143 | pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u" , |
144 | mp_opt->backup, mp_opt->join_id, |
145 | mp_opt->thmac, mp_opt->nonce); |
146 | } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { |
147 | ptr += 2; |
148 | memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); |
149 | pr_debug("MP_JOIN hmac" ); |
150 | } else { |
151 | mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ; |
152 | } |
153 | break; |
154 | |
155 | case MPTCPOPT_DSS: |
156 | pr_debug("DSS" ); |
157 | ptr++; |
158 | |
159 | /* we must clear 'mpc_map' be able to detect MP_CAPABLE |
160 | * map vs DSS map in mptcp_incoming_options(), and reconstruct |
161 | * map info accordingly |
162 | */ |
163 | mp_opt->mpc_map = 0; |
164 | flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
165 | mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; |
166 | mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; |
167 | mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; |
168 | mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; |
169 | mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); |
170 | |
171 | pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d" , |
172 | mp_opt->data_fin, mp_opt->dsn64, |
173 | mp_opt->use_map, mp_opt->ack64, |
174 | mp_opt->use_ack); |
175 | |
176 | expected_opsize = TCPOLEN_MPTCP_DSS_BASE; |
177 | |
178 | if (mp_opt->use_ack) { |
179 | if (mp_opt->ack64) |
180 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; |
181 | else |
182 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; |
183 | } |
184 | |
185 | if (mp_opt->use_map) { |
186 | if (mp_opt->dsn64) |
187 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; |
188 | else |
189 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; |
190 | } |
191 | |
192 | /* Always parse any csum presence combination, we will enforce |
193 | * RFC 8684 Section 3.3.0 checks later in subflow_data_ready |
194 | */ |
195 | if (opsize != expected_opsize && |
196 | opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) |
197 | break; |
198 | |
199 | mp_opt->suboptions |= OPTION_MPTCP_DSS; |
200 | if (mp_opt->use_ack) { |
201 | if (mp_opt->ack64) { |
202 | mp_opt->data_ack = get_unaligned_be64(p: ptr); |
203 | ptr += 8; |
204 | } else { |
205 | mp_opt->data_ack = get_unaligned_be32(p: ptr); |
206 | ptr += 4; |
207 | } |
208 | |
209 | pr_debug("data_ack=%llu" , mp_opt->data_ack); |
210 | } |
211 | |
212 | if (mp_opt->use_map) { |
213 | if (mp_opt->dsn64) { |
214 | mp_opt->data_seq = get_unaligned_be64(p: ptr); |
215 | ptr += 8; |
216 | } else { |
217 | mp_opt->data_seq = get_unaligned_be32(p: ptr); |
218 | ptr += 4; |
219 | } |
220 | |
221 | mp_opt->subflow_seq = get_unaligned_be32(p: ptr); |
222 | ptr += 4; |
223 | |
224 | mp_opt->data_len = get_unaligned_be16(p: ptr); |
225 | ptr += 2; |
226 | |
227 | if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) { |
228 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
229 | mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
230 | ptr += 2; |
231 | } |
232 | |
233 | pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u" , |
234 | mp_opt->data_seq, mp_opt->subflow_seq, |
235 | mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD), |
236 | mp_opt->csum); |
237 | } |
238 | |
239 | break; |
240 | |
241 | case MPTCPOPT_ADD_ADDR: |
242 | mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; |
243 | if (!mp_opt->echo) { |
244 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR || |
245 | opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) |
246 | mp_opt->addr.family = AF_INET; |
247 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
248 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || |
249 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) |
250 | mp_opt->addr.family = AF_INET6; |
251 | #endif |
252 | else |
253 | break; |
254 | } else { |
255 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || |
256 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) |
257 | mp_opt->addr.family = AF_INET; |
258 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
259 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || |
260 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) |
261 | mp_opt->addr.family = AF_INET6; |
262 | #endif |
263 | else |
264 | break; |
265 | } |
266 | |
267 | mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR; |
268 | mp_opt->addr.id = *ptr++; |
269 | mp_opt->addr.port = 0; |
270 | mp_opt->ahmac = 0; |
271 | if (mp_opt->addr.family == AF_INET) { |
272 | memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4); |
273 | ptr += 4; |
274 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || |
275 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { |
276 | mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
277 | ptr += 2; |
278 | } |
279 | } |
280 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
281 | else { |
282 | memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16); |
283 | ptr += 16; |
284 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || |
285 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { |
286 | mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
287 | ptr += 2; |
288 | } |
289 | } |
290 | #endif |
291 | if (!mp_opt->echo) { |
292 | mp_opt->ahmac = get_unaligned_be64(p: ptr); |
293 | ptr += 8; |
294 | } |
295 | pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d" , |
296 | (mp_opt->addr.family == AF_INET6) ? "6" : "" , |
297 | mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port)); |
298 | break; |
299 | |
300 | case MPTCPOPT_RM_ADDR: |
301 | if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || |
302 | opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) |
303 | break; |
304 | |
305 | ptr++; |
306 | |
307 | mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR; |
308 | mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; |
309 | for (i = 0; i < mp_opt->rm_list.nr; i++) |
310 | mp_opt->rm_list.ids[i] = *ptr++; |
311 | pr_debug("RM_ADDR: rm_list_nr=%d" , mp_opt->rm_list.nr); |
312 | break; |
313 | |
314 | case MPTCPOPT_MP_PRIO: |
315 | if (opsize != TCPOLEN_MPTCP_PRIO) |
316 | break; |
317 | |
318 | mp_opt->suboptions |= OPTION_MPTCP_PRIO; |
319 | mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; |
320 | pr_debug("MP_PRIO: prio=%d" , mp_opt->backup); |
321 | break; |
322 | |
323 | case MPTCPOPT_MP_FASTCLOSE: |
324 | if (opsize != TCPOLEN_MPTCP_FASTCLOSE) |
325 | break; |
326 | |
327 | ptr += 2; |
328 | mp_opt->rcvr_key = get_unaligned_be64(p: ptr); |
329 | ptr += 8; |
330 | mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE; |
331 | pr_debug("MP_FASTCLOSE: recv_key=%llu" , mp_opt->rcvr_key); |
332 | break; |
333 | |
334 | case MPTCPOPT_RST: |
335 | if (opsize != TCPOLEN_MPTCP_RST) |
336 | break; |
337 | |
338 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) |
339 | break; |
340 | |
341 | mp_opt->suboptions |= OPTION_MPTCP_RST; |
342 | flags = *ptr++; |
343 | mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT; |
344 | mp_opt->reset_reason = *ptr; |
345 | pr_debug("MP_RST: transient=%u reason=%u" , |
346 | mp_opt->reset_transient, mp_opt->reset_reason); |
347 | break; |
348 | |
349 | case MPTCPOPT_MP_FAIL: |
350 | if (opsize != TCPOLEN_MPTCP_FAIL) |
351 | break; |
352 | |
353 | ptr += 2; |
354 | mp_opt->suboptions |= OPTION_MPTCP_FAIL; |
355 | mp_opt->fail_seq = get_unaligned_be64(p: ptr); |
356 | pr_debug("MP_FAIL: data_seq=%llu" , mp_opt->fail_seq); |
357 | break; |
358 | |
359 | default: |
360 | break; |
361 | } |
362 | } |
363 | |
364 | void mptcp_get_options(const struct sk_buff *skb, |
365 | struct mptcp_options_received *mp_opt) |
366 | { |
367 | const struct tcphdr *th = tcp_hdr(skb); |
368 | const unsigned char *ptr; |
369 | int length; |
370 | |
371 | /* initialize option status */ |
372 | mp_opt->suboptions = 0; |
373 | |
374 | length = (th->doff * 4) - sizeof(struct tcphdr); |
375 | ptr = (const unsigned char *)(th + 1); |
376 | |
377 | while (length > 0) { |
378 | int opcode = *ptr++; |
379 | int opsize; |
380 | |
381 | switch (opcode) { |
382 | case TCPOPT_EOL: |
383 | return; |
384 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
385 | length--; |
386 | continue; |
387 | default: |
388 | if (length < 2) |
389 | return; |
390 | opsize = *ptr++; |
391 | if (opsize < 2) /* "silly options" */ |
392 | return; |
393 | if (opsize > length) |
394 | return; /* don't parse partial options */ |
395 | if (opcode == TCPOPT_MPTCP) |
396 | mptcp_parse_option(skb, ptr, opsize, mp_opt); |
397 | ptr += opsize - 2; |
398 | length -= opsize; |
399 | } |
400 | } |
401 | } |
402 | |
403 | bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
404 | unsigned int *size, struct mptcp_out_options *opts) |
405 | { |
406 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
407 | |
408 | /* we will use snd_isn to detect first pkt [re]transmission |
409 | * in mptcp_established_options_mp() |
410 | */ |
411 | subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; |
412 | if (subflow->request_mptcp) { |
413 | opts->suboptions = OPTION_MPTCP_MPC_SYN; |
414 | opts->csum_reqd = mptcp_is_checksum_enabled(net: sock_net(sk)); |
415 | opts->allow_join_id0 = mptcp_allow_join_id0(net: sock_net(sk)); |
416 | *size = TCPOLEN_MPTCP_MPC_SYN; |
417 | return true; |
418 | } else if (subflow->request_join) { |
419 | pr_debug("remote_token=%u, nonce=%u" , subflow->remote_token, |
420 | subflow->local_nonce); |
421 | opts->suboptions = OPTION_MPTCP_MPJ_SYN; |
422 | opts->join_id = subflow->local_id; |
423 | opts->token = subflow->remote_token; |
424 | opts->nonce = subflow->local_nonce; |
425 | opts->backup = subflow->request_bkup; |
426 | *size = TCPOLEN_MPTCP_MPJ_SYN; |
427 | return true; |
428 | } |
429 | return false; |
430 | } |
431 | |
432 | static void clear_3rdack_retransmission(struct sock *sk) |
433 | { |
434 | struct inet_connection_sock *icsk = inet_csk(sk); |
435 | |
436 | sk_stop_timer(sk, timer: &icsk->icsk_delack_timer); |
437 | icsk->icsk_ack.timeout = 0; |
438 | icsk->icsk_ack.ato = 0; |
439 | icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); |
440 | } |
441 | |
442 | static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
443 | bool snd_data_fin_enable, |
444 | unsigned int *size, |
445 | struct mptcp_out_options *opts) |
446 | { |
447 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
448 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
449 | struct mptcp_ext *mpext; |
450 | unsigned int data_len; |
451 | u8 len; |
452 | |
453 | /* When skb is not available, we better over-estimate the emitted |
454 | * options len. A full DSS option (28 bytes) is longer than |
455 | * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so |
456 | * tell the caller to defer the estimate to |
457 | * mptcp_established_options_dss(), which will reserve enough space. |
458 | */ |
459 | if (!skb) |
460 | return false; |
461 | |
462 | /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ |
463 | if (subflow->fully_established || snd_data_fin_enable || |
464 | subflow->snd_isn != TCP_SKB_CB(skb)->seq || |
465 | sk->sk_state != TCP_ESTABLISHED) |
466 | return false; |
467 | |
468 | if (subflow->mp_capable) { |
469 | mpext = mptcp_get_ext(skb); |
470 | data_len = mpext ? mpext->data_len : 0; |
471 | |
472 | /* we will check ops->data_len in mptcp_write_options() to |
473 | * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and |
474 | * TCPOLEN_MPTCP_MPC_ACK |
475 | */ |
476 | opts->data_len = data_len; |
477 | opts->suboptions = OPTION_MPTCP_MPC_ACK; |
478 | opts->sndr_key = subflow->local_key; |
479 | opts->rcvr_key = subflow->remote_key; |
480 | opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
481 | opts->allow_join_id0 = mptcp_allow_join_id0(net: sock_net(sk)); |
482 | |
483 | /* Section 3.1. |
484 | * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK |
485 | * packets that start the first subflow of an MPTCP connection, |
486 | * as well as the first packet that carries data |
487 | */ |
488 | if (data_len > 0) { |
489 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
490 | if (opts->csum_reqd) { |
491 | /* we need to propagate more info to csum the pseudo hdr */ |
492 | opts->data_seq = mpext->data_seq; |
493 | opts->subflow_seq = mpext->subflow_seq; |
494 | opts->csum = mpext->csum; |
495 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
496 | } |
497 | *size = ALIGN(len, 4); |
498 | } else { |
499 | *size = TCPOLEN_MPTCP_MPC_ACK; |
500 | } |
501 | |
502 | pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d" , |
503 | subflow, subflow->local_key, subflow->remote_key, |
504 | data_len); |
505 | |
506 | return true; |
507 | } else if (subflow->mp_join) { |
508 | opts->suboptions = OPTION_MPTCP_MPJ_ACK; |
509 | memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); |
510 | *size = TCPOLEN_MPTCP_MPJ_ACK; |
511 | pr_debug("subflow=%p" , subflow); |
512 | |
513 | /* we can use the full delegate action helper only from BH context |
514 | * If we are in process context - sk is flushing the backlog at |
515 | * socket lock release time - just set the appropriate flag, will |
516 | * be handled by the release callback |
517 | */ |
518 | if (sock_owned_by_user(sk)) |
519 | set_bit(MPTCP_DELEGATE_ACK, addr: &subflow->delegated_status); |
520 | else |
521 | mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK); |
522 | return true; |
523 | } |
524 | return false; |
525 | } |
526 | |
527 | static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
528 | struct sk_buff *skb, struct mptcp_ext *ext) |
529 | { |
530 | /* The write_seq value has already been incremented, so the actual |
531 | * sequence number for the DATA_FIN is one less. |
532 | */ |
533 | u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; |
534 | |
535 | if (!ext->use_map || !skb->len) { |
536 | /* RFC6824 requires a DSS mapping with specific values |
537 | * if DATA_FIN is set but no data payload is mapped |
538 | */ |
539 | ext->data_fin = 1; |
540 | ext->use_map = 1; |
541 | ext->dsn64 = 1; |
542 | ext->data_seq = data_fin_tx_seq; |
543 | ext->subflow_seq = 0; |
544 | ext->data_len = 1; |
545 | } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { |
546 | /* If there's an existing DSS mapping and it is the |
547 | * final mapping, DATA_FIN consumes 1 additional byte of |
548 | * mapping space. |
549 | */ |
550 | ext->data_fin = 1; |
551 | ext->data_len++; |
552 | } |
553 | } |
554 | |
555 | static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, |
556 | bool snd_data_fin_enable, |
557 | unsigned int *size, |
558 | struct mptcp_out_options *opts) |
559 | { |
560 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
561 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
562 | unsigned int dss_size = 0; |
563 | struct mptcp_ext *mpext; |
564 | unsigned int ack_size; |
565 | bool ret = false; |
566 | u64 ack_seq; |
567 | |
568 | opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
569 | mpext = skb ? mptcp_get_ext(skb) : NULL; |
570 | |
571 | if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { |
572 | unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; |
573 | |
574 | if (mpext) { |
575 | if (opts->csum_reqd) |
576 | map_size += TCPOLEN_MPTCP_DSS_CHECKSUM; |
577 | |
578 | opts->ext_copy = *mpext; |
579 | } |
580 | |
581 | dss_size = map_size; |
582 | if (skb && snd_data_fin_enable) |
583 | mptcp_write_data_fin(subflow, skb, ext: &opts->ext_copy); |
584 | opts->suboptions = OPTION_MPTCP_DSS; |
585 | ret = true; |
586 | } |
587 | |
588 | /* passive sockets msk will set the 'can_ack' after accept(), even |
589 | * if the first subflow may have the already the remote key handy |
590 | */ |
591 | opts->ext_copy.use_ack = 0; |
592 | if (!READ_ONCE(msk->can_ack)) { |
593 | *size = ALIGN(dss_size, 4); |
594 | return ret; |
595 | } |
596 | |
597 | ack_seq = READ_ONCE(msk->ack_seq); |
598 | if (READ_ONCE(msk->use_64bit_ack)) { |
599 | ack_size = TCPOLEN_MPTCP_DSS_ACK64; |
600 | opts->ext_copy.data_ack = ack_seq; |
601 | opts->ext_copy.ack64 = 1; |
602 | } else { |
603 | ack_size = TCPOLEN_MPTCP_DSS_ACK32; |
604 | opts->ext_copy.data_ack32 = (uint32_t)ack_seq; |
605 | opts->ext_copy.ack64 = 0; |
606 | } |
607 | opts->ext_copy.use_ack = 1; |
608 | opts->suboptions = OPTION_MPTCP_DSS; |
609 | WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); |
610 | |
611 | /* Add kind/length/subtype/flag overhead if mapping is not populated */ |
612 | if (dss_size == 0) |
613 | ack_size += TCPOLEN_MPTCP_DSS_BASE; |
614 | |
615 | dss_size += ack_size; |
616 | |
617 | *size = ALIGN(dss_size, 4); |
618 | return true; |
619 | } |
620 | |
621 | static u64 add_addr_generate_hmac(u64 key1, u64 key2, |
622 | struct mptcp_addr_info *addr) |
623 | { |
624 | u16 port = ntohs(addr->port); |
625 | u8 hmac[SHA256_DIGEST_SIZE]; |
626 | u8 msg[19]; |
627 | int i = 0; |
628 | |
629 | msg[i++] = addr->id; |
630 | if (addr->family == AF_INET) { |
631 | memcpy(&msg[i], &addr->addr.s_addr, 4); |
632 | i += 4; |
633 | } |
634 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
635 | else if (addr->family == AF_INET6) { |
636 | memcpy(&msg[i], &addr->addr6.s6_addr, 16); |
637 | i += 16; |
638 | } |
639 | #endif |
640 | msg[i++] = port >> 8; |
641 | msg[i++] = port & 0xFF; |
642 | |
643 | mptcp_crypto_hmac_sha(key1, key2, msg, len: i, hmac); |
644 | |
645 | return get_unaligned_be64(p: &hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
646 | } |
647 | |
648 | static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, |
649 | unsigned int *size, |
650 | unsigned int remaining, |
651 | struct mptcp_out_options *opts) |
652 | { |
653 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
654 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
655 | bool drop_other_suboptions = false; |
656 | unsigned int opt_size = *size; |
657 | bool echo; |
658 | int len; |
659 | |
660 | /* add addr will strip the existing options, be sure to avoid breaking |
661 | * MPC/MPJ handshakes |
662 | */ |
663 | if (!mptcp_pm_should_add_signal(msk) || |
664 | (opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) || |
665 | !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, addr: &opts->addr, |
666 | echo: &echo, drop_other_suboptions: &drop_other_suboptions)) |
667 | return false; |
668 | |
669 | if (drop_other_suboptions) |
670 | remaining += opt_size; |
671 | len = mptcp_add_addr_len(family: opts->addr.family, echo, port: !!opts->addr.port); |
672 | if (remaining < len) |
673 | return false; |
674 | |
675 | *size = len; |
676 | if (drop_other_suboptions) { |
677 | pr_debug("drop other suboptions" ); |
678 | opts->suboptions = 0; |
679 | |
680 | /* note that e.g. DSS could have written into the memory |
681 | * aliased by ahmac, we must reset the field here |
682 | * to avoid appending the hmac even for ADD_ADDR echo |
683 | * options |
684 | */ |
685 | opts->ahmac = 0; |
686 | *size -= opt_size; |
687 | } |
688 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR; |
689 | if (!echo) { |
690 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_ADDADDRTX); |
691 | opts->ahmac = add_addr_generate_hmac(key1: msk->local_key, |
692 | key2: msk->remote_key, |
693 | addr: &opts->addr); |
694 | } else { |
695 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_ECHOADDTX); |
696 | } |
697 | pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d" , |
698 | opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port)); |
699 | |
700 | return true; |
701 | } |
702 | |
703 | static bool mptcp_established_options_rm_addr(struct sock *sk, |
704 | unsigned int *size, |
705 | unsigned int remaining, |
706 | struct mptcp_out_options *opts) |
707 | { |
708 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
709 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
710 | struct mptcp_rm_list rm_list; |
711 | int i, len; |
712 | |
713 | if (!mptcp_pm_should_rm_signal(msk) || |
714 | !(mptcp_pm_rm_addr_signal(msk, remaining, rm_list: &rm_list))) |
715 | return false; |
716 | |
717 | len = mptcp_rm_addr_len(rm_list: &rm_list); |
718 | if (len < 0) |
719 | return false; |
720 | if (remaining < len) |
721 | return false; |
722 | |
723 | *size = len; |
724 | opts->suboptions |= OPTION_MPTCP_RM_ADDR; |
725 | opts->rm_list = rm_list; |
726 | |
727 | for (i = 0; i < opts->rm_list.nr; i++) |
728 | pr_debug("rm_list_ids[%d]=%d" , i, opts->rm_list.ids[i]); |
729 | MPTCP_ADD_STATS(net: sock_net(sk), field: MPTCP_MIB_RMADDRTX, val: opts->rm_list.nr); |
730 | return true; |
731 | } |
732 | |
733 | static bool mptcp_established_options_mp_prio(struct sock *sk, |
734 | unsigned int *size, |
735 | unsigned int remaining, |
736 | struct mptcp_out_options *opts) |
737 | { |
738 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
739 | |
740 | /* can't send MP_PRIO with MPC, as they share the same option space: |
741 | * 'backup'. Also it makes no sense at all |
742 | */ |
743 | if (!subflow->send_mp_prio || (opts->suboptions & OPTIONS_MPTCP_MPC)) |
744 | return false; |
745 | |
746 | /* account for the trailing 'nop' option */ |
747 | if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) |
748 | return false; |
749 | |
750 | *size = TCPOLEN_MPTCP_PRIO_ALIGN; |
751 | opts->suboptions |= OPTION_MPTCP_PRIO; |
752 | opts->backup = subflow->request_bkup; |
753 | |
754 | pr_debug("prio=%d" , opts->backup); |
755 | |
756 | return true; |
757 | } |
758 | |
759 | static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb, |
760 | unsigned int *size, |
761 | unsigned int remaining, |
762 | struct mptcp_out_options *opts) |
763 | { |
764 | const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
765 | |
766 | if (remaining < TCPOLEN_MPTCP_RST) |
767 | return false; |
768 | |
769 | *size = TCPOLEN_MPTCP_RST; |
770 | opts->suboptions |= OPTION_MPTCP_RST; |
771 | opts->reset_transient = subflow->reset_transient; |
772 | opts->reset_reason = subflow->reset_reason; |
773 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPRSTTX); |
774 | |
775 | return true; |
776 | } |
777 | |
778 | static bool mptcp_established_options_fastclose(struct sock *sk, |
779 | unsigned int *size, |
780 | unsigned int remaining, |
781 | struct mptcp_out_options *opts) |
782 | { |
783 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
784 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
785 | |
786 | if (likely(!subflow->send_fastclose)) |
787 | return false; |
788 | |
789 | if (remaining < TCPOLEN_MPTCP_FASTCLOSE) |
790 | return false; |
791 | |
792 | *size = TCPOLEN_MPTCP_FASTCLOSE; |
793 | opts->suboptions |= OPTION_MPTCP_FASTCLOSE; |
794 | opts->rcvr_key = msk->remote_key; |
795 | |
796 | pr_debug("FASTCLOSE key=%llu" , opts->rcvr_key); |
797 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPFASTCLOSETX); |
798 | return true; |
799 | } |
800 | |
801 | static bool mptcp_established_options_mp_fail(struct sock *sk, |
802 | unsigned int *size, |
803 | unsigned int remaining, |
804 | struct mptcp_out_options *opts) |
805 | { |
806 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
807 | |
808 | if (likely(!subflow->send_mp_fail)) |
809 | return false; |
810 | |
811 | if (remaining < TCPOLEN_MPTCP_FAIL) |
812 | return false; |
813 | |
814 | *size = TCPOLEN_MPTCP_FAIL; |
815 | opts->suboptions |= OPTION_MPTCP_FAIL; |
816 | opts->fail_seq = subflow->map_seq; |
817 | |
818 | pr_debug("MP_FAIL fail_seq=%llu" , opts->fail_seq); |
819 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPFAILTX); |
820 | |
821 | return true; |
822 | } |
823 | |
824 | bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, |
825 | unsigned int *size, unsigned int remaining, |
826 | struct mptcp_out_options *opts) |
827 | { |
828 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
829 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
830 | unsigned int opt_size = 0; |
831 | bool snd_data_fin; |
832 | bool ret = false; |
833 | |
834 | opts->suboptions = 0; |
835 | |
836 | if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb))) |
837 | return false; |
838 | |
839 | if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { |
840 | if (mptcp_established_options_fastclose(sk, size: &opt_size, remaining, opts) || |
841 | mptcp_established_options_mp_fail(sk, size: &opt_size, remaining, opts)) { |
842 | *size += opt_size; |
843 | remaining -= opt_size; |
844 | } |
845 | /* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */ |
846 | if (mptcp_established_options_rst(sk, skb, size: &opt_size, remaining, opts)) { |
847 | *size += opt_size; |
848 | remaining -= opt_size; |
849 | } |
850 | return true; |
851 | } |
852 | |
853 | snd_data_fin = mptcp_data_fin_enabled(msk); |
854 | if (mptcp_established_options_mp(sk, skb, snd_data_fin_enable: snd_data_fin, size: &opt_size, opts)) |
855 | ret = true; |
856 | else if (mptcp_established_options_dss(sk, skb, snd_data_fin_enable: snd_data_fin, size: &opt_size, opts)) { |
857 | unsigned int mp_fail_size; |
858 | |
859 | ret = true; |
860 | if (mptcp_established_options_mp_fail(sk, size: &mp_fail_size, |
861 | remaining: remaining - opt_size, opts)) { |
862 | *size += opt_size + mp_fail_size; |
863 | remaining -= opt_size - mp_fail_size; |
864 | return true; |
865 | } |
866 | } |
867 | |
868 | /* we reserved enough space for the above options, and exceeding the |
869 | * TCP option space would be fatal |
870 | */ |
871 | if (WARN_ON_ONCE(opt_size > remaining)) |
872 | return false; |
873 | |
874 | *size += opt_size; |
875 | remaining -= opt_size; |
876 | if (mptcp_established_options_add_addr(sk, skb, size: &opt_size, remaining, opts)) { |
877 | *size += opt_size; |
878 | remaining -= opt_size; |
879 | ret = true; |
880 | } else if (mptcp_established_options_rm_addr(sk, size: &opt_size, remaining, opts)) { |
881 | *size += opt_size; |
882 | remaining -= opt_size; |
883 | ret = true; |
884 | } |
885 | |
886 | if (mptcp_established_options_mp_prio(sk, size: &opt_size, remaining, opts)) { |
887 | *size += opt_size; |
888 | remaining -= opt_size; |
889 | ret = true; |
890 | } |
891 | |
892 | return ret; |
893 | } |
894 | |
895 | bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
896 | struct mptcp_out_options *opts) |
897 | { |
898 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(rsk: req); |
899 | |
900 | if (subflow_req->mp_capable) { |
901 | opts->suboptions = OPTION_MPTCP_MPC_SYNACK; |
902 | opts->sndr_key = subflow_req->local_key; |
903 | opts->csum_reqd = subflow_req->csum_reqd; |
904 | opts->allow_join_id0 = subflow_req->allow_join_id0; |
905 | *size = TCPOLEN_MPTCP_MPC_SYNACK; |
906 | pr_debug("subflow_req=%p, local_key=%llu" , |
907 | subflow_req, subflow_req->local_key); |
908 | return true; |
909 | } else if (subflow_req->mp_join) { |
910 | opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; |
911 | opts->backup = subflow_req->backup; |
912 | opts->join_id = subflow_req->local_id; |
913 | opts->thmac = subflow_req->thmac; |
914 | opts->nonce = subflow_req->local_nonce; |
915 | pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u" , |
916 | subflow_req, opts->backup, opts->join_id, |
917 | opts->thmac, opts->nonce); |
918 | *size = TCPOLEN_MPTCP_MPJ_SYNACK; |
919 | return true; |
920 | } |
921 | return false; |
922 | } |
923 | |
924 | static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, |
925 | struct mptcp_subflow_context *subflow, |
926 | struct sk_buff *skb, |
927 | struct mptcp_options_received *mp_opt) |
928 | { |
929 | /* here we can process OoO, in-window pkts, only in-sequence 4th ack |
930 | * will make the subflow fully established |
931 | */ |
932 | if (likely(subflow->fully_established)) { |
933 | /* on passive sockets, check for 3rd ack retransmission |
934 | * note that msk is always set by subflow_syn_recv_sock() |
935 | * for mp_join subflows |
936 | */ |
937 | if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && |
938 | TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && |
939 | subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) && |
940 | !subflow->request_join) |
941 | tcp_send_ack(sk: ssk); |
942 | goto check_notify; |
943 | } |
944 | |
945 | /* we must process OoO packets before the first subflow is fully |
946 | * established. OoO packets are instead a protocol violation |
947 | * for MP_JOIN subflows as the peer must not send any data |
948 | * before receiving the forth ack - cfr. RFC 8684 section 3.2. |
949 | */ |
950 | if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { |
951 | if (subflow->mp_join) |
952 | goto reset; |
953 | if (subflow->is_mptfo && mp_opt->suboptions & OPTION_MPTCP_MPC_ACK) |
954 | goto set_fully_established; |
955 | return subflow->mp_capable; |
956 | } |
957 | |
958 | if (subflow->remote_key_valid && |
959 | (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) || |
960 | ((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo))) { |
961 | /* subflows are fully established as soon as we get any |
962 | * additional ack, including ADD_ADDR. |
963 | */ |
964 | subflow->fully_established = 1; |
965 | WRITE_ONCE(msk->fully_established, true); |
966 | goto check_notify; |
967 | } |
968 | |
969 | /* If the first established packet does not contain MP_CAPABLE + data |
970 | * then fallback to TCP. Fallback scenarios requires a reset for |
971 | * MP_JOIN subflows. |
972 | */ |
973 | if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) { |
974 | if (subflow->mp_join) |
975 | goto reset; |
976 | subflow->mp_capable = 0; |
977 | pr_fallback(msk); |
978 | mptcp_do_fallback(ssk); |
979 | return false; |
980 | } |
981 | |
982 | if (mp_opt->deny_join_id0) |
983 | WRITE_ONCE(msk->pm.remote_deny_join_id0, true); |
984 | |
985 | set_fully_established: |
986 | if (unlikely(!READ_ONCE(msk->pm.server_side))) |
987 | pr_warn_once("bogus mpc option on established client sk" ); |
988 | mptcp_subflow_fully_established(subflow, mp_opt); |
989 | |
990 | check_notify: |
991 | /* if the subflow is not already linked into the conn_list, we can't |
992 | * notify the PM: this subflow is still on the listener queue |
993 | * and the PM possibly acquiring the subflow lock could race with |
994 | * the listener close |
995 | */ |
996 | if (likely(subflow->pm_notified) || list_empty(head: &subflow->node)) |
997 | return true; |
998 | |
999 | subflow->pm_notified = 1; |
1000 | if (subflow->mp_join) { |
1001 | clear_3rdack_retransmission(sk: ssk); |
1002 | mptcp_pm_subflow_established(msk); |
1003 | } else { |
1004 | mptcp_pm_fully_established(msk, ssk); |
1005 | } |
1006 | return true; |
1007 | |
1008 | reset: |
1009 | mptcp_subflow_reset(ssk); |
1010 | return false; |
1011 | } |
1012 | |
1013 | u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq) |
1014 | { |
1015 | u32 old_seq32, cur_seq32; |
1016 | |
1017 | old_seq32 = (u32)old_seq; |
1018 | cur_seq32 = (u32)cur_seq; |
1019 | cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32; |
1020 | if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32))) |
1021 | return cur_seq + (1LL << 32); |
1022 | |
1023 | /* reverse wrap could happen, too */ |
1024 | if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32))) |
1025 | return cur_seq - (1LL << 32); |
1026 | return cur_seq; |
1027 | } |
1028 | |
1029 | static void __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una) |
1030 | { |
1031 | msk->bytes_acked += new_snd_una - msk->snd_una; |
1032 | msk->snd_una = new_snd_una; |
1033 | } |
1034 | |
1035 | static void ack_update_msk(struct mptcp_sock *msk, |
1036 | struct sock *ssk, |
1037 | struct mptcp_options_received *mp_opt) |
1038 | { |
1039 | u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); |
1040 | struct sock *sk = (struct sock *)msk; |
1041 | u64 old_snd_una; |
1042 | |
1043 | mptcp_data_lock(sk); |
1044 | |
1045 | /* avoid ack expansion on update conflict, to reduce the risk of |
1046 | * wrongly expanding to a future ack sequence number, which is way |
1047 | * more dangerous than missing an ack |
1048 | */ |
1049 | old_snd_una = msk->snd_una; |
1050 | new_snd_una = mptcp_expand_seq(old_seq: old_snd_una, cur_seq: mp_opt->data_ack, use_64bit: mp_opt->ack64); |
1051 | |
1052 | /* ACK for data not even sent yet? Ignore.*/ |
1053 | if (unlikely(after64(new_snd_una, snd_nxt))) |
1054 | new_snd_una = old_snd_una; |
1055 | |
1056 | new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; |
1057 | |
1058 | if (after64(new_wnd_end, msk->wnd_end)) |
1059 | msk->wnd_end = new_wnd_end; |
1060 | |
1061 | /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ |
1062 | if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) |
1063 | __mptcp_check_push(sk, ssk); |
1064 | |
1065 | if (after64(new_snd_una, old_snd_una)) { |
1066 | __mptcp_snd_una_update(msk, new_snd_una); |
1067 | __mptcp_data_acked(sk); |
1068 | } |
1069 | mptcp_data_unlock(sk); |
1070 | |
1071 | trace_ack_update_msk(data_ack: mp_opt->data_ack, |
1072 | old_snd_una, new_snd_una, |
1073 | new_wnd_end, msk_wnd_end: msk->wnd_end); |
1074 | } |
1075 | |
1076 | bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) |
1077 | { |
1078 | /* Skip if DATA_FIN was already received. |
1079 | * If updating simultaneously with the recvmsg loop, values |
1080 | * should match. If they mismatch, the peer is misbehaving and |
1081 | * we will prefer the most recent information. |
1082 | */ |
1083 | if (READ_ONCE(msk->rcv_data_fin)) |
1084 | return false; |
1085 | |
1086 | WRITE_ONCE(msk->rcv_data_fin_seq, |
1087 | mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); |
1088 | WRITE_ONCE(msk->rcv_data_fin, 1); |
1089 | |
1090 | return true; |
1091 | } |
1092 | |
1093 | static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
1094 | struct mptcp_options_received *mp_opt) |
1095 | { |
1096 | u64 hmac = 0; |
1097 | |
1098 | if (mp_opt->echo) |
1099 | return true; |
1100 | |
1101 | hmac = add_addr_generate_hmac(key1: msk->remote_key, |
1102 | key2: msk->local_key, |
1103 | addr: &mp_opt->addr); |
1104 | |
1105 | pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n" , |
1106 | msk, hmac, mp_opt->ahmac); |
1107 | |
1108 | return hmac == mp_opt->ahmac; |
1109 | } |
1110 | |
1111 | /* Return false if a subflow has been reset, else return true */ |
1112 | bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) |
1113 | { |
1114 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
1115 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
1116 | struct mptcp_options_received mp_opt; |
1117 | struct mptcp_ext *mpext; |
1118 | |
1119 | if (__mptcp_check_fallback(msk)) { |
1120 | /* Keep it simple and unconditionally trigger send data cleanup and |
1121 | * pending queue spooling. We will need to acquire the data lock |
1122 | * for more accurate checks, and once the lock is acquired, such |
1123 | * helpers are cheap. |
1124 | */ |
1125 | mptcp_data_lock(subflow->conn); |
1126 | if (sk_stream_memory_free(sk)) |
1127 | __mptcp_check_push(sk: subflow->conn, ssk: sk); |
1128 | |
1129 | /* on fallback we just need to ignore the msk-level snd_una, as |
1130 | * this is really plain TCP |
1131 | */ |
1132 | __mptcp_snd_una_update(msk, READ_ONCE(msk->snd_nxt)); |
1133 | |
1134 | __mptcp_data_acked(sk: subflow->conn); |
1135 | mptcp_data_unlock(subflow->conn); |
1136 | return true; |
1137 | } |
1138 | |
1139 | mptcp_get_options(skb, mp_opt: &mp_opt); |
1140 | |
1141 | /* The subflow can be in close state only if check_fully_established() |
1142 | * just sent a reset. If so, tell the caller to ignore the current packet. |
1143 | */ |
1144 | if (!check_fully_established(msk, ssk: sk, subflow, skb, mp_opt: &mp_opt)) |
1145 | return sk->sk_state != TCP_CLOSE; |
1146 | |
1147 | if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) { |
1148 | if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) && |
1149 | msk->local_key == mp_opt.rcvr_key) { |
1150 | WRITE_ONCE(msk->rcv_fastclose, true); |
1151 | mptcp_schedule_work(sk: (struct sock *)msk); |
1152 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPFASTCLOSERX); |
1153 | } |
1154 | |
1155 | if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) && |
1156 | add_addr_hmac_valid(msk, mp_opt: &mp_opt)) { |
1157 | if (!mp_opt.echo) { |
1158 | mptcp_pm_add_addr_received(ssk: sk, addr: &mp_opt.addr); |
1159 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_ADDADDR); |
1160 | } else { |
1161 | mptcp_pm_add_addr_echoed(msk, addr: &mp_opt.addr); |
1162 | mptcp_pm_del_add_timer(msk, addr: &mp_opt.addr, check_id: true); |
1163 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_ECHOADD); |
1164 | } |
1165 | |
1166 | if (mp_opt.addr.port) |
1167 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_PORTADD); |
1168 | } |
1169 | |
1170 | if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR) |
1171 | mptcp_pm_rm_addr_received(msk, rm_list: &mp_opt.rm_list); |
1172 | |
1173 | if (mp_opt.suboptions & OPTION_MPTCP_PRIO) { |
1174 | mptcp_pm_mp_prio_received(sk, bkup: mp_opt.backup); |
1175 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPPRIORX); |
1176 | } |
1177 | |
1178 | if (mp_opt.suboptions & OPTION_MPTCP_FAIL) { |
1179 | mptcp_pm_mp_fail_received(sk, fail_seq: mp_opt.fail_seq); |
1180 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPFAILRX); |
1181 | } |
1182 | |
1183 | if (mp_opt.suboptions & OPTION_MPTCP_RST) { |
1184 | subflow->reset_seen = 1; |
1185 | subflow->reset_reason = mp_opt.reset_reason; |
1186 | subflow->reset_transient = mp_opt.reset_transient; |
1187 | MPTCP_INC_STATS(net: sock_net(sk), field: MPTCP_MIB_MPRSTRX); |
1188 | } |
1189 | |
1190 | if (!(mp_opt.suboptions & OPTION_MPTCP_DSS)) |
1191 | return true; |
1192 | } |
1193 | |
1194 | /* we can't wait for recvmsg() to update the ack_seq, otherwise |
1195 | * monodirectional flows will stuck |
1196 | */ |
1197 | if (mp_opt.use_ack) |
1198 | ack_update_msk(msk, ssk: sk, mp_opt: &mp_opt); |
1199 | |
1200 | /* Zero-data-length packets are dropped by the caller and not |
1201 | * propagated to the MPTCP layer, so the skb extension does not |
1202 | * need to be allocated or populated. DATA_FIN information, if |
1203 | * present, needs to be updated here before the skb is freed. |
1204 | */ |
1205 | if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { |
1206 | if (mp_opt.data_fin && mp_opt.data_len == 1 && |
1207 | mptcp_update_rcv_data_fin(msk, data_fin_seq: mp_opt.data_seq, use_64bit: mp_opt.dsn64)) |
1208 | mptcp_schedule_work(sk: (struct sock *)msk); |
1209 | |
1210 | return true; |
1211 | } |
1212 | |
1213 | mpext = skb_ext_add(skb, id: SKB_EXT_MPTCP); |
1214 | if (!mpext) |
1215 | return true; |
1216 | |
1217 | memset(mpext, 0, sizeof(*mpext)); |
1218 | |
1219 | if (likely(mp_opt.use_map)) { |
1220 | if (mp_opt.mpc_map) { |
1221 | /* this is an MP_CAPABLE carrying MPTCP data |
1222 | * we know this map the first chunk of data |
1223 | */ |
1224 | mptcp_crypto_key_sha(key: subflow->remote_key, NULL, |
1225 | idsn: &mpext->data_seq); |
1226 | mpext->data_seq++; |
1227 | mpext->subflow_seq = 1; |
1228 | mpext->dsn64 = 1; |
1229 | mpext->mpc_map = 1; |
1230 | mpext->data_fin = 0; |
1231 | } else { |
1232 | mpext->data_seq = mp_opt.data_seq; |
1233 | mpext->subflow_seq = mp_opt.subflow_seq; |
1234 | mpext->dsn64 = mp_opt.dsn64; |
1235 | mpext->data_fin = mp_opt.data_fin; |
1236 | } |
1237 | mpext->data_len = mp_opt.data_len; |
1238 | mpext->use_map = 1; |
1239 | mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD); |
1240 | |
1241 | if (mpext->csum_reqd) |
1242 | mpext->csum = mp_opt.csum; |
1243 | } |
1244 | |
1245 | return true; |
1246 | } |
1247 | |
1248 | static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th) |
1249 | { |
1250 | const struct sock *ssk = (const struct sock *)tp; |
1251 | struct mptcp_subflow_context *subflow; |
1252 | u64 ack_seq, rcv_wnd_old, rcv_wnd_new; |
1253 | struct mptcp_sock *msk; |
1254 | u32 new_win; |
1255 | u64 win; |
1256 | |
1257 | subflow = mptcp_subflow_ctx(sk: ssk); |
1258 | msk = mptcp_sk(subflow->conn); |
1259 | |
1260 | ack_seq = READ_ONCE(msk->ack_seq); |
1261 | rcv_wnd_new = ack_seq + tp->rcv_wnd; |
1262 | |
1263 | rcv_wnd_old = atomic64_read(v: &msk->rcv_wnd_sent); |
1264 | if (after64(rcv_wnd_new, rcv_wnd_old)) { |
1265 | u64 rcv_wnd; |
1266 | |
1267 | for (;;) { |
1268 | rcv_wnd = atomic64_cmpxchg(v: &msk->rcv_wnd_sent, old: rcv_wnd_old, new: rcv_wnd_new); |
1269 | |
1270 | if (rcv_wnd == rcv_wnd_old) |
1271 | break; |
1272 | |
1273 | rcv_wnd_old = rcv_wnd; |
1274 | if (before64(seq1: rcv_wnd_new, seq2: rcv_wnd_old)) { |
1275 | MPTCP_INC_STATS(net: sock_net(sk: ssk), field: MPTCP_MIB_RCVWNDCONFLICTUPDATE); |
1276 | goto raise_win; |
1277 | } |
1278 | MPTCP_INC_STATS(net: sock_net(sk: ssk), field: MPTCP_MIB_RCVWNDCONFLICT); |
1279 | } |
1280 | return; |
1281 | } |
1282 | |
1283 | if (rcv_wnd_new != rcv_wnd_old) { |
1284 | raise_win: |
1285 | win = rcv_wnd_old - ack_seq; |
1286 | tp->rcv_wnd = min_t(u64, win, U32_MAX); |
1287 | new_win = tp->rcv_wnd; |
1288 | |
1289 | /* Make sure we do not exceed the maximum possible |
1290 | * scaled window. |
1291 | */ |
1292 | if (unlikely(th->syn)) |
1293 | new_win = min(new_win, 65535U) << tp->rx_opt.rcv_wscale; |
1294 | if (!tp->rx_opt.rcv_wscale && |
1295 | READ_ONCE(sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows)) |
1296 | new_win = min(new_win, MAX_TCP_WINDOW); |
1297 | else |
1298 | new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale)); |
1299 | |
1300 | /* RFC1323 scaling applied */ |
1301 | new_win >>= tp->rx_opt.rcv_wscale; |
1302 | th->window = htons(new_win); |
1303 | MPTCP_INC_STATS(net: sock_net(sk: ssk), field: MPTCP_MIB_RCVWNDSHARED); |
1304 | } |
1305 | } |
1306 | |
1307 | __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum) |
1308 | { |
1309 | struct csum_pseudo_header ; |
1310 | __wsum csum; |
1311 | |
1312 | /* cfr RFC 8684 3.3.1.: |
1313 | * the data sequence number used in the pseudo-header is |
1314 | * always the 64-bit value, irrespective of what length is used in the |
1315 | * DSS option itself. |
1316 | */ |
1317 | header.data_seq = cpu_to_be64(data_seq); |
1318 | header.subflow_seq = htonl(subflow_seq); |
1319 | header.data_len = htons(data_len); |
1320 | header.csum = 0; |
1321 | |
1322 | csum = csum_partial(buff: &header, len: sizeof(header), sum); |
1323 | return csum_fold(sum: csum); |
1324 | } |
1325 | |
1326 | static __sum16 mptcp_make_csum(const struct mptcp_ext *mpext) |
1327 | { |
1328 | return __mptcp_make_csum(data_seq: mpext->data_seq, subflow_seq: mpext->subflow_seq, data_len: mpext->data_len, |
1329 | sum: ~csum_unfold(n: mpext->csum)); |
1330 | } |
1331 | |
1332 | static void put_len_csum(u16 len, __sum16 csum, void *data) |
1333 | { |
1334 | __sum16 *sumptr = data + 2; |
1335 | __be16 *ptr = data; |
1336 | |
1337 | put_unaligned_be16(val: len, p: ptr); |
1338 | |
1339 | put_unaligned(csum, sumptr); |
1340 | } |
1341 | |
1342 | void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp, |
1343 | struct mptcp_out_options *opts) |
1344 | { |
1345 | const struct sock *ssk = (const struct sock *)tp; |
1346 | struct mptcp_subflow_context *subflow; |
1347 | |
1348 | /* Which options can be used together? |
1349 | * |
1350 | * X: mutually exclusive |
1351 | * O: often used together |
1352 | * C: can be used together in some cases |
1353 | * P: could be used together but we prefer not to (optimisations) |
1354 | * |
1355 | * Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC | |
1356 | * ------|------|------|------|------|------|------|------|------| |
1357 | * MPC |------|------|------|------|------|------|------|------| |
1358 | * MPJ | X |------|------|------|------|------|------|------| |
1359 | * DSS | X | X |------|------|------|------|------|------| |
1360 | * ADD | X | X | P |------|------|------|------|------| |
1361 | * RM | C | C | C | P |------|------|------|------| |
1362 | * PRIO | X | C | C | C | C |------|------|------| |
1363 | * FAIL | X | X | C | X | X | X |------|------| |
1364 | * FC | X | X | X | X | X | X | X |------| |
1365 | * RST | X | X | X | X | X | X | O | O | |
1366 | * ------|------|------|------|------|------|------|------|------| |
1367 | * |
1368 | * The same applies in mptcp_established_options() function. |
1369 | */ |
1370 | if (likely(OPTION_MPTCP_DSS & opts->suboptions)) { |
1371 | struct mptcp_ext *mpext = &opts->ext_copy; |
1372 | u8 len = TCPOLEN_MPTCP_DSS_BASE; |
1373 | u8 flags = 0; |
1374 | |
1375 | if (mpext->use_ack) { |
1376 | flags = MPTCP_DSS_HAS_ACK; |
1377 | if (mpext->ack64) { |
1378 | len += TCPOLEN_MPTCP_DSS_ACK64; |
1379 | flags |= MPTCP_DSS_ACK64; |
1380 | } else { |
1381 | len += TCPOLEN_MPTCP_DSS_ACK32; |
1382 | } |
1383 | } |
1384 | |
1385 | if (mpext->use_map) { |
1386 | len += TCPOLEN_MPTCP_DSS_MAP64; |
1387 | |
1388 | /* Use only 64-bit mapping flags for now, add |
1389 | * support for optional 32-bit mappings later. |
1390 | */ |
1391 | flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; |
1392 | if (mpext->data_fin) |
1393 | flags |= MPTCP_DSS_DATA_FIN; |
1394 | |
1395 | if (opts->csum_reqd) |
1396 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
1397 | } |
1398 | |
1399 | *ptr++ = mptcp_option(MPTCPOPT_DSS, len, nib: 0, field: flags); |
1400 | |
1401 | if (mpext->use_ack) { |
1402 | if (mpext->ack64) { |
1403 | put_unaligned_be64(val: mpext->data_ack, p: ptr); |
1404 | ptr += 2; |
1405 | } else { |
1406 | put_unaligned_be32(val: mpext->data_ack32, p: ptr); |
1407 | ptr += 1; |
1408 | } |
1409 | } |
1410 | |
1411 | if (mpext->use_map) { |
1412 | put_unaligned_be64(val: mpext->data_seq, p: ptr); |
1413 | ptr += 2; |
1414 | put_unaligned_be32(val: mpext->subflow_seq, p: ptr); |
1415 | ptr += 1; |
1416 | if (opts->csum_reqd) { |
1417 | /* data_len == 0 is reserved for the infinite mapping, |
1418 | * the checksum will also be set to 0. |
1419 | */ |
1420 | put_len_csum(len: mpext->data_len, |
1421 | csum: (mpext->data_len ? mptcp_make_csum(mpext) : 0), |
1422 | data: ptr); |
1423 | } else { |
1424 | put_unaligned_be32(val: mpext->data_len << 16 | |
1425 | TCPOPT_NOP << 8 | TCPOPT_NOP, p: ptr); |
1426 | } |
1427 | ptr += 1; |
1428 | } |
1429 | |
1430 | /* We might need to add MP_FAIL options in rare cases */ |
1431 | if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) |
1432 | goto mp_fail; |
1433 | } else if (OPTIONS_MPTCP_MPC & opts->suboptions) { |
1434 | u8 len, flag = MPTCP_CAP_HMAC_SHA256; |
1435 | |
1436 | if (OPTION_MPTCP_MPC_SYN & opts->suboptions) { |
1437 | len = TCPOLEN_MPTCP_MPC_SYN; |
1438 | } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) { |
1439 | len = TCPOLEN_MPTCP_MPC_SYNACK; |
1440 | } else if (opts->data_len) { |
1441 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
1442 | if (opts->csum_reqd) |
1443 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
1444 | } else { |
1445 | len = TCPOLEN_MPTCP_MPC_ACK; |
1446 | } |
1447 | |
1448 | if (opts->csum_reqd) |
1449 | flag |= MPTCP_CAP_CHECKSUM_REQD; |
1450 | |
1451 | if (!opts->allow_join_id0) |
1452 | flag |= MPTCP_CAP_DENY_JOIN_ID0; |
1453 | |
1454 | *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, |
1455 | MPTCP_SUPPORTED_VERSION, |
1456 | field: flag); |
1457 | |
1458 | if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & |
1459 | opts->suboptions)) |
1460 | goto mp_capable_done; |
1461 | |
1462 | put_unaligned_be64(val: opts->sndr_key, p: ptr); |
1463 | ptr += 2; |
1464 | if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
1465 | goto mp_capable_done; |
1466 | |
1467 | put_unaligned_be64(val: opts->rcvr_key, p: ptr); |
1468 | ptr += 2; |
1469 | if (!opts->data_len) |
1470 | goto mp_capable_done; |
1471 | |
1472 | if (opts->csum_reqd) { |
1473 | put_len_csum(len: opts->data_len, |
1474 | csum: __mptcp_make_csum(data_seq: opts->data_seq, |
1475 | subflow_seq: opts->subflow_seq, |
1476 | data_len: opts->data_len, |
1477 | sum: ~csum_unfold(n: opts->csum)), |
1478 | data: ptr); |
1479 | } else { |
1480 | put_unaligned_be32(val: opts->data_len << 16 | |
1481 | TCPOPT_NOP << 8 | TCPOPT_NOP, p: ptr); |
1482 | } |
1483 | ptr += 1; |
1484 | |
1485 | /* MPC is additionally mutually exclusive with MP_PRIO */ |
1486 | goto mp_capable_done; |
1487 | } else if (OPTIONS_MPTCP_MPJ & opts->suboptions) { |
1488 | if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { |
1489 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
1490 | TCPOLEN_MPTCP_MPJ_SYN, |
1491 | nib: opts->backup, field: opts->join_id); |
1492 | put_unaligned_be32(val: opts->token, p: ptr); |
1493 | ptr += 1; |
1494 | put_unaligned_be32(val: opts->nonce, p: ptr); |
1495 | ptr += 1; |
1496 | } else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { |
1497 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
1498 | TCPOLEN_MPTCP_MPJ_SYNACK, |
1499 | nib: opts->backup, field: opts->join_id); |
1500 | put_unaligned_be64(val: opts->thmac, p: ptr); |
1501 | ptr += 2; |
1502 | put_unaligned_be32(val: opts->nonce, p: ptr); |
1503 | ptr += 1; |
1504 | } else { |
1505 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
1506 | TCPOLEN_MPTCP_MPJ_ACK, nib: 0, field: 0); |
1507 | memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); |
1508 | ptr += 5; |
1509 | } |
1510 | } else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { |
1511 | u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; |
1512 | u8 echo = MPTCP_ADDR_ECHO; |
1513 | |
1514 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
1515 | if (opts->addr.family == AF_INET6) |
1516 | len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; |
1517 | #endif |
1518 | |
1519 | if (opts->addr.port) |
1520 | len += TCPOLEN_MPTCP_PORT_LEN; |
1521 | |
1522 | if (opts->ahmac) { |
1523 | len += sizeof(opts->ahmac); |
1524 | echo = 0; |
1525 | } |
1526 | |
1527 | *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, |
1528 | len, nib: echo, field: opts->addr.id); |
1529 | if (opts->addr.family == AF_INET) { |
1530 | memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4); |
1531 | ptr += 1; |
1532 | } |
1533 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
1534 | else if (opts->addr.family == AF_INET6) { |
1535 | memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16); |
1536 | ptr += 4; |
1537 | } |
1538 | #endif |
1539 | |
1540 | if (!opts->addr.port) { |
1541 | if (opts->ahmac) { |
1542 | put_unaligned_be64(val: opts->ahmac, p: ptr); |
1543 | ptr += 2; |
1544 | } |
1545 | } else { |
1546 | u16 port = ntohs(opts->addr.port); |
1547 | |
1548 | if (opts->ahmac) { |
1549 | u8 *bptr = (u8 *)ptr; |
1550 | |
1551 | put_unaligned_be16(val: port, p: bptr); |
1552 | bptr += 2; |
1553 | put_unaligned_be64(val: opts->ahmac, p: bptr); |
1554 | bptr += 8; |
1555 | put_unaligned_be16(TCPOPT_NOP << 8 | |
1556 | TCPOPT_NOP, p: bptr); |
1557 | |
1558 | ptr += 3; |
1559 | } else { |
1560 | put_unaligned_be32(val: port << 16 | |
1561 | TCPOPT_NOP << 8 | |
1562 | TCPOPT_NOP, p: ptr); |
1563 | ptr += 1; |
1564 | } |
1565 | } |
1566 | } else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) { |
1567 | /* FASTCLOSE is mutually exclusive with others except RST */ |
1568 | *ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE, |
1569 | TCPOLEN_MPTCP_FASTCLOSE, |
1570 | nib: 0, field: 0); |
1571 | put_unaligned_be64(val: opts->rcvr_key, p: ptr); |
1572 | ptr += 2; |
1573 | |
1574 | if (OPTION_MPTCP_RST & opts->suboptions) |
1575 | goto mp_rst; |
1576 | return; |
1577 | } else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) { |
1578 | mp_fail: |
1579 | /* MP_FAIL is mutually exclusive with others except RST */ |
1580 | subflow = mptcp_subflow_ctx(sk: ssk); |
1581 | subflow->send_mp_fail = 0; |
1582 | |
1583 | *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL, |
1584 | TCPOLEN_MPTCP_FAIL, |
1585 | nib: 0, field: 0); |
1586 | put_unaligned_be64(val: opts->fail_seq, p: ptr); |
1587 | ptr += 2; |
1588 | |
1589 | if (OPTION_MPTCP_RST & opts->suboptions) |
1590 | goto mp_rst; |
1591 | return; |
1592 | } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) { |
1593 | mp_rst: |
1594 | *ptr++ = mptcp_option(MPTCPOPT_RST, |
1595 | TCPOLEN_MPTCP_RST, |
1596 | nib: opts->reset_transient, |
1597 | field: opts->reset_reason); |
1598 | return; |
1599 | } |
1600 | |
1601 | if (OPTION_MPTCP_PRIO & opts->suboptions) { |
1602 | subflow = mptcp_subflow_ctx(sk: ssk); |
1603 | subflow->send_mp_prio = 0; |
1604 | |
1605 | *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, |
1606 | TCPOLEN_MPTCP_PRIO, |
1607 | nib: opts->backup, TCPOPT_NOP); |
1608 | |
1609 | MPTCP_INC_STATS(net: sock_net(sk: ssk), field: MPTCP_MIB_MPPRIOTX); |
1610 | } |
1611 | |
1612 | mp_capable_done: |
1613 | if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { |
1614 | u8 i = 1; |
1615 | |
1616 | *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, |
1617 | TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, |
1618 | nib: 0, field: opts->rm_list.ids[0]); |
1619 | |
1620 | while (i < opts->rm_list.nr) { |
1621 | u8 id1, id2, id3, id4; |
1622 | |
1623 | id1 = opts->rm_list.ids[i]; |
1624 | id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; |
1625 | id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; |
1626 | id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; |
1627 | put_unaligned_be32(val: id1 << 24 | id2 << 16 | id3 << 8 | id4, p: ptr); |
1628 | ptr += 1; |
1629 | i += 4; |
1630 | } |
1631 | } |
1632 | |
1633 | if (tp) |
1634 | mptcp_set_rwin(tp, th); |
1635 | } |
1636 | |
1637 | __be32 mptcp_get_reset_option(const struct sk_buff *skb) |
1638 | { |
1639 | const struct mptcp_ext *ext = mptcp_get_ext(skb); |
1640 | u8 flags, reason; |
1641 | |
1642 | if (ext) { |
1643 | flags = ext->reset_transient; |
1644 | reason = ext->reset_reason; |
1645 | |
1646 | return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST, |
1647 | nib: flags, field: reason); |
1648 | } |
1649 | |
1650 | return htonl(0u); |
1651 | } |
1652 | EXPORT_SYMBOL_GPL(mptcp_get_reset_option); |
1653 | |