xref: /openbmc/linux/net/mptcp/sockopt.c (revision 3fc7c707)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Multipath TCP
3  *
4  * Copyright (c) 2021, Red Hat.
5  */
6 
7 #define pr_fmt(fmt) "MPTCP: " fmt
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <net/sock.h>
12 #include <net/protocol.h>
13 #include <net/tcp.h>
14 #include <net/mptcp.h>
15 #include "protocol.h"
16 
17 #define MIN_INFO_OPTLEN_SIZE		16
18 #define MIN_FULL_INFO_OPTLEN_SIZE	40
19 
20 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
21 {
22 	msk_owned_by_me(msk);
23 
24 	if (likely(!__mptcp_check_fallback(msk)))
25 		return NULL;
26 
27 	return msk->first;
28 }
29 
30 static u32 sockopt_seq_reset(const struct sock *sk)
31 {
32 	sock_owned_by_me(sk);
33 
34 	/* Highbits contain state.  Allows to distinguish sockopt_seq
35 	 * of listener and established:
36 	 * s0 = new_listener()
37 	 * sockopt(s0) - seq is 1
38 	 * s1 = accept(s0) - s1 inherits seq 1 if listener sk (s0)
39 	 * sockopt(s0) - seq increments to 2 on s0
40 	 * sockopt(s1) // seq increments to 2 on s1 (different option)
41 	 * new ssk completes join, inherits options from s0 // seq 2
42 	 * Needs sync from mptcp join logic, but ssk->seq == msk->seq
43 	 *
44 	 * Set High order bits to sk_state so ssk->seq == msk->seq test
45 	 * will fail.
46 	 */
47 
48 	return (u32)sk->sk_state << 24u;
49 }
50 
51 static void sockopt_seq_inc(struct mptcp_sock *msk)
52 {
53 	u32 seq = (msk->setsockopt_seq + 1) & 0x00ffffff;
54 
55 	msk->setsockopt_seq = sockopt_seq_reset((struct sock *)msk) + seq;
56 }
57 
58 static int mptcp_get_int_option(struct mptcp_sock *msk, sockptr_t optval,
59 				unsigned int optlen, int *val)
60 {
61 	if (optlen < sizeof(int))
62 		return -EINVAL;
63 
64 	if (copy_from_sockptr(val, optval, sizeof(*val)))
65 		return -EFAULT;
66 
67 	return 0;
68 }
69 
70 static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, int val)
71 {
72 	struct mptcp_subflow_context *subflow;
73 	struct sock *sk = (struct sock *)msk;
74 
75 	lock_sock(sk);
76 	sockopt_seq_inc(msk);
77 
78 	mptcp_for_each_subflow(msk, subflow) {
79 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
80 		bool slow = lock_sock_fast(ssk);
81 
82 		switch (optname) {
83 		case SO_DEBUG:
84 			sock_valbool_flag(ssk, SOCK_DBG, !!val);
85 			break;
86 		case SO_KEEPALIVE:
87 			if (ssk->sk_prot->keepalive)
88 				ssk->sk_prot->keepalive(ssk, !!val);
89 			sock_valbool_flag(ssk, SOCK_KEEPOPEN, !!val);
90 			break;
91 		case SO_PRIORITY:
92 			ssk->sk_priority = val;
93 			break;
94 		case SO_SNDBUF:
95 		case SO_SNDBUFFORCE:
96 			ssk->sk_userlocks |= SOCK_SNDBUF_LOCK;
97 			WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
98 			break;
99 		case SO_RCVBUF:
100 		case SO_RCVBUFFORCE:
101 			ssk->sk_userlocks |= SOCK_RCVBUF_LOCK;
102 			WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
103 			break;
104 		case SO_MARK:
105 			if (READ_ONCE(ssk->sk_mark) != sk->sk_mark) {
106 				WRITE_ONCE(ssk->sk_mark, sk->sk_mark);
107 				sk_dst_reset(ssk);
108 			}
109 			break;
110 		case SO_INCOMING_CPU:
111 			WRITE_ONCE(ssk->sk_incoming_cpu, val);
112 			break;
113 		}
114 
115 		subflow->setsockopt_seq = msk->setsockopt_seq;
116 		unlock_sock_fast(ssk, slow);
117 	}
118 
119 	release_sock(sk);
120 }
121 
122 static int mptcp_sol_socket_intval(struct mptcp_sock *msk, int optname, int val)
123 {
124 	sockptr_t optval = KERNEL_SOCKPTR(&val);
125 	struct sock *sk = (struct sock *)msk;
126 	int ret;
127 
128 	ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
129 			      optval, sizeof(val));
130 	if (ret)
131 		return ret;
132 
133 	mptcp_sol_socket_sync_intval(msk, optname, val);
134 	return 0;
135 }
136 
137 static void mptcp_so_incoming_cpu(struct mptcp_sock *msk, int val)
138 {
139 	struct sock *sk = (struct sock *)msk;
140 
141 	WRITE_ONCE(sk->sk_incoming_cpu, val);
142 
143 	mptcp_sol_socket_sync_intval(msk, SO_INCOMING_CPU, val);
144 }
145 
146 static int mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optname, int val)
147 {
148 	sockptr_t optval = KERNEL_SOCKPTR(&val);
149 	struct mptcp_subflow_context *subflow;
150 	struct sock *sk = (struct sock *)msk;
151 	int ret;
152 
153 	ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
154 			      optval, sizeof(val));
155 	if (ret)
156 		return ret;
157 
158 	lock_sock(sk);
159 	mptcp_for_each_subflow(msk, subflow) {
160 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
161 		bool slow = lock_sock_fast(ssk);
162 
163 		sock_set_timestamp(sk, optname, !!val);
164 		unlock_sock_fast(ssk, slow);
165 	}
166 
167 	release_sock(sk);
168 	return 0;
169 }
170 
171 static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
172 					   sockptr_t optval,
173 					   unsigned int optlen)
174 {
175 	int val, ret;
176 
177 	ret = mptcp_get_int_option(msk, optval, optlen, &val);
178 	if (ret)
179 		return ret;
180 
181 	switch (optname) {
182 	case SO_KEEPALIVE:
183 		mptcp_sol_socket_sync_intval(msk, optname, val);
184 		return 0;
185 	case SO_DEBUG:
186 	case SO_MARK:
187 	case SO_PRIORITY:
188 	case SO_SNDBUF:
189 	case SO_SNDBUFFORCE:
190 	case SO_RCVBUF:
191 	case SO_RCVBUFFORCE:
192 		return mptcp_sol_socket_intval(msk, optname, val);
193 	case SO_INCOMING_CPU:
194 		mptcp_so_incoming_cpu(msk, val);
195 		return 0;
196 	case SO_TIMESTAMP_OLD:
197 	case SO_TIMESTAMP_NEW:
198 	case SO_TIMESTAMPNS_OLD:
199 	case SO_TIMESTAMPNS_NEW:
200 		return mptcp_setsockopt_sol_socket_tstamp(msk, optname, val);
201 	}
202 
203 	return -ENOPROTOOPT;
204 }
205 
206 static int mptcp_setsockopt_sol_socket_timestamping(struct mptcp_sock *msk,
207 						    int optname,
208 						    sockptr_t optval,
209 						    unsigned int optlen)
210 {
211 	struct mptcp_subflow_context *subflow;
212 	struct sock *sk = (struct sock *)msk;
213 	struct so_timestamping timestamping;
214 	int ret;
215 
216 	if (optlen == sizeof(timestamping)) {
217 		if (copy_from_sockptr(&timestamping, optval,
218 				      sizeof(timestamping)))
219 			return -EFAULT;
220 	} else if (optlen == sizeof(int)) {
221 		memset(&timestamping, 0, sizeof(timestamping));
222 
223 		if (copy_from_sockptr(&timestamping.flags, optval, sizeof(int)))
224 			return -EFAULT;
225 	} else {
226 		return -EINVAL;
227 	}
228 
229 	ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
230 			      KERNEL_SOCKPTR(&timestamping),
231 			      sizeof(timestamping));
232 	if (ret)
233 		return ret;
234 
235 	lock_sock(sk);
236 
237 	mptcp_for_each_subflow(msk, subflow) {
238 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
239 		bool slow = lock_sock_fast(ssk);
240 
241 		sock_set_timestamping(sk, optname, timestamping);
242 		unlock_sock_fast(ssk, slow);
243 	}
244 
245 	release_sock(sk);
246 
247 	return 0;
248 }
249 
250 static int mptcp_setsockopt_sol_socket_linger(struct mptcp_sock *msk, sockptr_t optval,
251 					      unsigned int optlen)
252 {
253 	struct mptcp_subflow_context *subflow;
254 	struct sock *sk = (struct sock *)msk;
255 	struct linger ling;
256 	sockptr_t kopt;
257 	int ret;
258 
259 	if (optlen < sizeof(ling))
260 		return -EINVAL;
261 
262 	if (copy_from_sockptr(&ling, optval, sizeof(ling)))
263 		return -EFAULT;
264 
265 	kopt = KERNEL_SOCKPTR(&ling);
266 	ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, SO_LINGER, kopt, sizeof(ling));
267 	if (ret)
268 		return ret;
269 
270 	lock_sock(sk);
271 	sockopt_seq_inc(msk);
272 	mptcp_for_each_subflow(msk, subflow) {
273 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
274 		bool slow = lock_sock_fast(ssk);
275 
276 		if (!ling.l_onoff) {
277 			sock_reset_flag(ssk, SOCK_LINGER);
278 		} else {
279 			ssk->sk_lingertime = sk->sk_lingertime;
280 			sock_set_flag(ssk, SOCK_LINGER);
281 		}
282 
283 		subflow->setsockopt_seq = msk->setsockopt_seq;
284 		unlock_sock_fast(ssk, slow);
285 	}
286 
287 	release_sock(sk);
288 	return 0;
289 }
290 
291 static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
292 				       sockptr_t optval, unsigned int optlen)
293 {
294 	struct sock *sk = (struct sock *)msk;
295 	struct sock *ssk;
296 	int ret;
297 
298 	switch (optname) {
299 	case SO_REUSEPORT:
300 	case SO_REUSEADDR:
301 	case SO_BINDTODEVICE:
302 	case SO_BINDTOIFINDEX:
303 		lock_sock(sk);
304 		ssk = __mptcp_nmpc_sk(msk);
305 		if (IS_ERR(ssk)) {
306 			release_sock(sk);
307 			return PTR_ERR(ssk);
308 		}
309 
310 		ret = sk_setsockopt(ssk, SOL_SOCKET, optname, optval, optlen);
311 		if (ret == 0) {
312 			if (optname == SO_REUSEPORT)
313 				sk->sk_reuseport = ssk->sk_reuseport;
314 			else if (optname == SO_REUSEADDR)
315 				sk->sk_reuse = ssk->sk_reuse;
316 			else if (optname == SO_BINDTODEVICE)
317 				sk->sk_bound_dev_if = ssk->sk_bound_dev_if;
318 			else if (optname == SO_BINDTOIFINDEX)
319 				sk->sk_bound_dev_if = ssk->sk_bound_dev_if;
320 		}
321 		release_sock(sk);
322 		return ret;
323 	case SO_KEEPALIVE:
324 	case SO_PRIORITY:
325 	case SO_SNDBUF:
326 	case SO_SNDBUFFORCE:
327 	case SO_RCVBUF:
328 	case SO_RCVBUFFORCE:
329 	case SO_MARK:
330 	case SO_INCOMING_CPU:
331 	case SO_DEBUG:
332 	case SO_TIMESTAMP_OLD:
333 	case SO_TIMESTAMP_NEW:
334 	case SO_TIMESTAMPNS_OLD:
335 	case SO_TIMESTAMPNS_NEW:
336 		return mptcp_setsockopt_sol_socket_int(msk, optname, optval,
337 						       optlen);
338 	case SO_TIMESTAMPING_OLD:
339 	case SO_TIMESTAMPING_NEW:
340 		return mptcp_setsockopt_sol_socket_timestamping(msk, optname,
341 								optval, optlen);
342 	case SO_LINGER:
343 		return mptcp_setsockopt_sol_socket_linger(msk, optval, optlen);
344 	case SO_RCVLOWAT:
345 	case SO_RCVTIMEO_OLD:
346 	case SO_RCVTIMEO_NEW:
347 	case SO_SNDTIMEO_OLD:
348 	case SO_SNDTIMEO_NEW:
349 	case SO_BUSY_POLL:
350 	case SO_PREFER_BUSY_POLL:
351 	case SO_BUSY_POLL_BUDGET:
352 		/* No need to copy: only relevant for msk */
353 		return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
354 	case SO_NO_CHECK:
355 	case SO_DONTROUTE:
356 	case SO_BROADCAST:
357 	case SO_BSDCOMPAT:
358 	case SO_PASSCRED:
359 	case SO_PASSPIDFD:
360 	case SO_PASSSEC:
361 	case SO_RXQ_OVFL:
362 	case SO_WIFI_STATUS:
363 	case SO_NOFCS:
364 	case SO_SELECT_ERR_QUEUE:
365 		return 0;
366 	}
367 
368 	/* SO_OOBINLINE is not supported, let's avoid the related mess
369 	 * SO_ATTACH_FILTER, SO_ATTACH_BPF, SO_ATTACH_REUSEPORT_CBPF,
370 	 * SO_DETACH_REUSEPORT_BPF, SO_DETACH_FILTER, SO_LOCK_FILTER,
371 	 * we must be careful with subflows
372 	 *
373 	 * SO_ATTACH_REUSEPORT_EBPF is not supported, at it checks
374 	 * explicitly the sk_protocol field
375 	 *
376 	 * SO_PEEK_OFF is unsupported, as it is for plain TCP
377 	 * SO_MAX_PACING_RATE is unsupported, we must be careful with subflows
378 	 * SO_CNX_ADVICE is currently unsupported, could possibly be relevant,
379 	 * but likely needs careful design
380 	 *
381 	 * SO_ZEROCOPY is currently unsupported, TODO in sndmsg
382 	 * SO_TXTIME is currently unsupported
383 	 */
384 
385 	return -EOPNOTSUPP;
386 }
387 
388 static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
389 			       sockptr_t optval, unsigned int optlen)
390 {
391 	struct sock *sk = (struct sock *)msk;
392 	int ret = -EOPNOTSUPP;
393 	struct sock *ssk;
394 
395 	switch (optname) {
396 	case IPV6_V6ONLY:
397 	case IPV6_TRANSPARENT:
398 	case IPV6_FREEBIND:
399 		lock_sock(sk);
400 		ssk = __mptcp_nmpc_sk(msk);
401 		if (IS_ERR(ssk)) {
402 			release_sock(sk);
403 			return PTR_ERR(ssk);
404 		}
405 
406 		ret = tcp_setsockopt(ssk, SOL_IPV6, optname, optval, optlen);
407 		if (ret != 0) {
408 			release_sock(sk);
409 			return ret;
410 		}
411 
412 		sockopt_seq_inc(msk);
413 
414 		switch (optname) {
415 		case IPV6_V6ONLY:
416 			sk->sk_ipv6only = ssk->sk_ipv6only;
417 			break;
418 		case IPV6_TRANSPARENT:
419 			inet_assign_bit(TRANSPARENT, sk,
420 					inet_test_bit(TRANSPARENT, ssk));
421 			break;
422 		case IPV6_FREEBIND:
423 			inet_assign_bit(FREEBIND, sk,
424 					inet_test_bit(FREEBIND, ssk));
425 			break;
426 		}
427 
428 		release_sock(sk);
429 		break;
430 	}
431 
432 	return ret;
433 }
434 
435 static bool mptcp_supported_sockopt(int level, int optname)
436 {
437 	if (level == SOL_IP) {
438 		switch (optname) {
439 		/* should work fine */
440 		case IP_FREEBIND:
441 		case IP_TRANSPARENT:
442 
443 		/* the following are control cmsg related */
444 		case IP_PKTINFO:
445 		case IP_RECVTTL:
446 		case IP_RECVTOS:
447 		case IP_RECVOPTS:
448 		case IP_RETOPTS:
449 		case IP_PASSSEC:
450 		case IP_RECVORIGDSTADDR:
451 		case IP_CHECKSUM:
452 		case IP_RECVFRAGSIZE:
453 
454 		/* common stuff that need some love */
455 		case IP_TOS:
456 		case IP_TTL:
457 		case IP_BIND_ADDRESS_NO_PORT:
458 		case IP_MTU_DISCOVER:
459 		case IP_RECVERR:
460 
461 		/* possibly less common may deserve some love */
462 		case IP_MINTTL:
463 
464 		/* the following is apparently a no-op for plain TCP */
465 		case IP_RECVERR_RFC4884:
466 			return true;
467 		}
468 
469 		/* IP_OPTIONS is not supported, needs subflow care */
470 		/* IP_HDRINCL, IP_NODEFRAG are not supported, RAW specific */
471 		/* IP_MULTICAST_TTL, IP_MULTICAST_LOOP, IP_UNICAST_IF,
472 		 * IP_ADD_MEMBERSHIP, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_MEMBERSHIP,
473 		 * IP_DROP_SOURCE_MEMBERSHIP, IP_BLOCK_SOURCE, IP_UNBLOCK_SOURCE,
474 		 * MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP MCAST_JOIN_SOURCE_GROUP,
475 		 * MCAST_LEAVE_SOURCE_GROUP, MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE,
476 		 * MCAST_MSFILTER, IP_MULTICAST_ALL are not supported, better not deal
477 		 * with mcast stuff
478 		 */
479 		/* IP_IPSEC_POLICY, IP_XFRM_POLICY are nut supported, unrelated here */
480 		return false;
481 	}
482 	if (level == SOL_IPV6) {
483 		switch (optname) {
484 		case IPV6_V6ONLY:
485 
486 		/* the following are control cmsg related */
487 		case IPV6_RECVPKTINFO:
488 		case IPV6_2292PKTINFO:
489 		case IPV6_RECVHOPLIMIT:
490 		case IPV6_2292HOPLIMIT:
491 		case IPV6_RECVRTHDR:
492 		case IPV6_2292RTHDR:
493 		case IPV6_RECVHOPOPTS:
494 		case IPV6_2292HOPOPTS:
495 		case IPV6_RECVDSTOPTS:
496 		case IPV6_2292DSTOPTS:
497 		case IPV6_RECVTCLASS:
498 		case IPV6_FLOWINFO:
499 		case IPV6_RECVPATHMTU:
500 		case IPV6_RECVORIGDSTADDR:
501 		case IPV6_RECVFRAGSIZE:
502 
503 		/* the following ones need some love but are quite common */
504 		case IPV6_TCLASS:
505 		case IPV6_TRANSPARENT:
506 		case IPV6_FREEBIND:
507 		case IPV6_PKTINFO:
508 		case IPV6_2292PKTOPTIONS:
509 		case IPV6_UNICAST_HOPS:
510 		case IPV6_MTU_DISCOVER:
511 		case IPV6_MTU:
512 		case IPV6_RECVERR:
513 		case IPV6_FLOWINFO_SEND:
514 		case IPV6_FLOWLABEL_MGR:
515 		case IPV6_MINHOPCOUNT:
516 		case IPV6_DONTFRAG:
517 		case IPV6_AUTOFLOWLABEL:
518 
519 		/* the following one is a no-op for plain TCP */
520 		case IPV6_RECVERR_RFC4884:
521 			return true;
522 		}
523 
524 		/* IPV6_HOPOPTS, IPV6_RTHDRDSTOPTS, IPV6_RTHDR, IPV6_DSTOPTS are
525 		 * not supported
526 		 */
527 		/* IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_IF,
528 		 * IPV6_MULTICAST_IF, IPV6_ADDRFORM,
529 		 * IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_JOIN_ANYCAST,
530 		 * IPV6_LEAVE_ANYCAST, IPV6_MULTICAST_ALL, MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP,
531 		 * MCAST_JOIN_SOURCE_GROUP, MCAST_LEAVE_SOURCE_GROUP,
532 		 * MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE, MCAST_MSFILTER
533 		 * are not supported better not deal with mcast
534 		 */
535 		/* IPV6_ROUTER_ALERT, IPV6_ROUTER_ALERT_ISOLATE are not supported, since are evil */
536 
537 		/* IPV6_IPSEC_POLICY, IPV6_XFRM_POLICY are not supported */
538 		/* IPV6_ADDR_PREFERENCES is not supported, we must be careful with subflows */
539 		return false;
540 	}
541 	if (level == SOL_TCP) {
542 		switch (optname) {
543 		/* the following are no-op or should work just fine */
544 		case TCP_THIN_DUPACK:
545 		case TCP_DEFER_ACCEPT:
546 
547 		/* the following need some love */
548 		case TCP_MAXSEG:
549 		case TCP_NODELAY:
550 		case TCP_THIN_LINEAR_TIMEOUTS:
551 		case TCP_CONGESTION:
552 		case TCP_CORK:
553 		case TCP_KEEPIDLE:
554 		case TCP_KEEPINTVL:
555 		case TCP_KEEPCNT:
556 		case TCP_SYNCNT:
557 		case TCP_SAVE_SYN:
558 		case TCP_LINGER2:
559 		case TCP_WINDOW_CLAMP:
560 		case TCP_QUICKACK:
561 		case TCP_USER_TIMEOUT:
562 		case TCP_TIMESTAMP:
563 		case TCP_NOTSENT_LOWAT:
564 		case TCP_TX_DELAY:
565 		case TCP_INQ:
566 		case TCP_FASTOPEN:
567 		case TCP_FASTOPEN_CONNECT:
568 		case TCP_FASTOPEN_KEY:
569 		case TCP_FASTOPEN_NO_COOKIE:
570 			return true;
571 		}
572 
573 		/* TCP_MD5SIG, TCP_MD5SIG_EXT are not supported, MD5 is not compatible with MPTCP */
574 
575 		/* TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS,
576 		 * TCP_REPAIR_WINDOW are not supported, better avoid this mess
577 		 */
578 	}
579 	return false;
580 }
581 
582 static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t optval,
583 					       unsigned int optlen)
584 {
585 	struct mptcp_subflow_context *subflow;
586 	struct sock *sk = (struct sock *)msk;
587 	char name[TCP_CA_NAME_MAX];
588 	bool cap_net_admin;
589 	int ret;
590 
591 	if (optlen < 1)
592 		return -EINVAL;
593 
594 	ret = strncpy_from_sockptr(name, optval,
595 				   min_t(long, TCP_CA_NAME_MAX - 1, optlen));
596 	if (ret < 0)
597 		return -EFAULT;
598 
599 	name[ret] = 0;
600 
601 	cap_net_admin = ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN);
602 
603 	ret = 0;
604 	lock_sock(sk);
605 	sockopt_seq_inc(msk);
606 	mptcp_for_each_subflow(msk, subflow) {
607 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
608 		int err;
609 
610 		lock_sock(ssk);
611 		err = tcp_set_congestion_control(ssk, name, true, cap_net_admin);
612 		if (err < 0 && ret == 0)
613 			ret = err;
614 		subflow->setsockopt_seq = msk->setsockopt_seq;
615 		release_sock(ssk);
616 	}
617 
618 	if (ret == 0)
619 		strcpy(msk->ca_name, name);
620 
621 	release_sock(sk);
622 	return ret;
623 }
624 
625 static int mptcp_setsockopt_sol_tcp_cork(struct mptcp_sock *msk, sockptr_t optval,
626 					 unsigned int optlen)
627 {
628 	struct mptcp_subflow_context *subflow;
629 	struct sock *sk = (struct sock *)msk;
630 	int val;
631 
632 	if (optlen < sizeof(int))
633 		return -EINVAL;
634 
635 	if (copy_from_sockptr(&val, optval, sizeof(val)))
636 		return -EFAULT;
637 
638 	lock_sock(sk);
639 	sockopt_seq_inc(msk);
640 	msk->cork = !!val;
641 	mptcp_for_each_subflow(msk, subflow) {
642 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
643 
644 		lock_sock(ssk);
645 		__tcp_sock_set_cork(ssk, !!val);
646 		release_sock(ssk);
647 	}
648 	if (!val)
649 		mptcp_check_and_set_pending(sk);
650 	release_sock(sk);
651 
652 	return 0;
653 }
654 
655 static int mptcp_setsockopt_sol_tcp_nodelay(struct mptcp_sock *msk, sockptr_t optval,
656 					    unsigned int optlen)
657 {
658 	struct mptcp_subflow_context *subflow;
659 	struct sock *sk = (struct sock *)msk;
660 	int val;
661 
662 	if (optlen < sizeof(int))
663 		return -EINVAL;
664 
665 	if (copy_from_sockptr(&val, optval, sizeof(val)))
666 		return -EFAULT;
667 
668 	lock_sock(sk);
669 	sockopt_seq_inc(msk);
670 	msk->nodelay = !!val;
671 	mptcp_for_each_subflow(msk, subflow) {
672 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
673 
674 		lock_sock(ssk);
675 		__tcp_sock_set_nodelay(ssk, !!val);
676 		release_sock(ssk);
677 	}
678 	if (val)
679 		mptcp_check_and_set_pending(sk);
680 	release_sock(sk);
681 
682 	return 0;
683 }
684 
685 static int mptcp_setsockopt_sol_ip_set_transparent(struct mptcp_sock *msk, int optname,
686 						   sockptr_t optval, unsigned int optlen)
687 {
688 	struct sock *sk = (struct sock *)msk;
689 	struct sock *ssk;
690 	int err;
691 
692 	err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
693 	if (err != 0)
694 		return err;
695 
696 	lock_sock(sk);
697 
698 	ssk = __mptcp_nmpc_sk(msk);
699 	if (IS_ERR(ssk)) {
700 		release_sock(sk);
701 		return PTR_ERR(ssk);
702 	}
703 
704 	switch (optname) {
705 	case IP_FREEBIND:
706 		inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
707 		break;
708 	case IP_TRANSPARENT:
709 		inet_assign_bit(TRANSPARENT, ssk,
710 				inet_test_bit(TRANSPARENT, sk));
711 		break;
712 	default:
713 		release_sock(sk);
714 		WARN_ON_ONCE(1);
715 		return -EOPNOTSUPP;
716 	}
717 
718 	sockopt_seq_inc(msk);
719 	release_sock(sk);
720 	return 0;
721 }
722 
723 static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
724 				       sockptr_t optval, unsigned int optlen)
725 {
726 	struct mptcp_subflow_context *subflow;
727 	struct sock *sk = (struct sock *)msk;
728 	int err, val;
729 
730 	err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
731 
732 	if (err != 0)
733 		return err;
734 
735 	lock_sock(sk);
736 	sockopt_seq_inc(msk);
737 	val = inet_sk(sk)->tos;
738 	mptcp_for_each_subflow(msk, subflow) {
739 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
740 
741 		__ip_sock_set_tos(ssk, val);
742 	}
743 	release_sock(sk);
744 
745 	return 0;
746 }
747 
748 static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
749 			       sockptr_t optval, unsigned int optlen)
750 {
751 	switch (optname) {
752 	case IP_FREEBIND:
753 	case IP_TRANSPARENT:
754 		return mptcp_setsockopt_sol_ip_set_transparent(msk, optname, optval, optlen);
755 	case IP_TOS:
756 		return mptcp_setsockopt_v4_set_tos(msk, optname, optval, optlen);
757 	}
758 
759 	return -EOPNOTSUPP;
760 }
761 
762 static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
763 					  sockptr_t optval, unsigned int optlen)
764 {
765 	struct sock *sk = (struct sock *)msk;
766 	struct sock *ssk;
767 	int ret;
768 
769 	/* Limit to first subflow, before the connection establishment */
770 	lock_sock(sk);
771 	ssk = __mptcp_nmpc_sk(msk);
772 	if (IS_ERR(ssk)) {
773 		ret = PTR_ERR(ssk);
774 		goto unlock;
775 	}
776 
777 	ret = tcp_setsockopt(ssk, level, optname, optval, optlen);
778 
779 unlock:
780 	release_sock(sk);
781 	return ret;
782 }
783 
784 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
785 				    sockptr_t optval, unsigned int optlen)
786 {
787 	struct sock *sk = (void *)msk;
788 	int ret, val;
789 
790 	switch (optname) {
791 	case TCP_INQ:
792 		ret = mptcp_get_int_option(msk, optval, optlen, &val);
793 		if (ret)
794 			return ret;
795 		if (val < 0 || val > 1)
796 			return -EINVAL;
797 
798 		lock_sock(sk);
799 		msk->recvmsg_inq = !!val;
800 		release_sock(sk);
801 		return 0;
802 	case TCP_ULP:
803 		return -EOPNOTSUPP;
804 	case TCP_CONGESTION:
805 		return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen);
806 	case TCP_CORK:
807 		return mptcp_setsockopt_sol_tcp_cork(msk, optval, optlen);
808 	case TCP_NODELAY:
809 		return mptcp_setsockopt_sol_tcp_nodelay(msk, optval, optlen);
810 	case TCP_DEFER_ACCEPT:
811 		/* See tcp.c: TCP_DEFER_ACCEPT does not fail */
812 		mptcp_setsockopt_first_sf_only(msk, SOL_TCP, optname, optval, optlen);
813 		return 0;
814 	case TCP_FASTOPEN:
815 	case TCP_FASTOPEN_CONNECT:
816 	case TCP_FASTOPEN_KEY:
817 	case TCP_FASTOPEN_NO_COOKIE:
818 		return mptcp_setsockopt_first_sf_only(msk, SOL_TCP, optname,
819 						      optval, optlen);
820 	}
821 
822 	return -EOPNOTSUPP;
823 }
824 
825 int mptcp_setsockopt(struct sock *sk, int level, int optname,
826 		     sockptr_t optval, unsigned int optlen)
827 {
828 	struct mptcp_sock *msk = mptcp_sk(sk);
829 	struct sock *ssk;
830 
831 	pr_debug("msk=%p", msk);
832 
833 	if (level == SOL_SOCKET)
834 		return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
835 
836 	if (!mptcp_supported_sockopt(level, optname))
837 		return -ENOPROTOOPT;
838 
839 	/* @@ the meaning of setsockopt() when the socket is connected and
840 	 * there are multiple subflows is not yet defined. It is up to the
841 	 * MPTCP-level socket to configure the subflows until the subflow
842 	 * is in TCP fallback, when TCP socket options are passed through
843 	 * to the one remaining subflow.
844 	 */
845 	lock_sock(sk);
846 	ssk = __mptcp_tcp_fallback(msk);
847 	release_sock(sk);
848 	if (ssk)
849 		return tcp_setsockopt(ssk, level, optname, optval, optlen);
850 
851 	if (level == SOL_IP)
852 		return mptcp_setsockopt_v4(msk, optname, optval, optlen);
853 
854 	if (level == SOL_IPV6)
855 		return mptcp_setsockopt_v6(msk, optname, optval, optlen);
856 
857 	if (level == SOL_TCP)
858 		return mptcp_setsockopt_sol_tcp(msk, optname, optval, optlen);
859 
860 	return -EOPNOTSUPP;
861 }
862 
863 static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
864 					  char __user *optval, int __user *optlen)
865 {
866 	struct sock *sk = (struct sock *)msk;
867 	struct sock *ssk;
868 	int ret;
869 
870 	lock_sock(sk);
871 	ssk = msk->first;
872 	if (ssk) {
873 		ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
874 		goto out;
875 	}
876 
877 	ssk = __mptcp_nmpc_sk(msk);
878 	if (IS_ERR(ssk)) {
879 		ret = PTR_ERR(ssk);
880 		goto out;
881 	}
882 
883 	ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
884 
885 out:
886 	release_sock(sk);
887 	return ret;
888 }
889 
890 void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
891 {
892 	struct sock *sk = (struct sock *)msk;
893 	u32 flags = 0;
894 	bool slow;
895 
896 	memset(info, 0, sizeof(*info));
897 
898 	info->mptcpi_subflows = READ_ONCE(msk->pm.subflows);
899 	info->mptcpi_add_addr_signal = READ_ONCE(msk->pm.add_addr_signaled);
900 	info->mptcpi_add_addr_accepted = READ_ONCE(msk->pm.add_addr_accepted);
901 	info->mptcpi_local_addr_used = READ_ONCE(msk->pm.local_addr_used);
902 
903 	if (inet_sk_state_load(sk) == TCP_LISTEN)
904 		return;
905 
906 	/* The following limits only make sense for the in-kernel PM */
907 	if (mptcp_pm_is_kernel(msk)) {
908 		info->mptcpi_subflows_max =
909 			mptcp_pm_get_subflows_max(msk);
910 		info->mptcpi_add_addr_signal_max =
911 			mptcp_pm_get_add_addr_signal_max(msk);
912 		info->mptcpi_add_addr_accepted_max =
913 			mptcp_pm_get_add_addr_accept_max(msk);
914 		info->mptcpi_local_addr_max =
915 			mptcp_pm_get_local_addr_max(msk);
916 	}
917 
918 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags))
919 		flags |= MPTCP_INFO_FLAG_FALLBACK;
920 	if (READ_ONCE(msk->can_ack))
921 		flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
922 	info->mptcpi_flags = flags;
923 	mptcp_data_lock(sk);
924 	info->mptcpi_snd_una = msk->snd_una;
925 	info->mptcpi_rcv_nxt = msk->ack_seq;
926 	info->mptcpi_bytes_acked = msk->bytes_acked;
927 	mptcp_data_unlock(sk);
928 
929 	slow = lock_sock_fast(sk);
930 	info->mptcpi_csum_enabled = msk->csum_enabled;
931 	info->mptcpi_token = msk->token;
932 	info->mptcpi_write_seq = msk->write_seq;
933 	info->mptcpi_retransmits = inet_csk(sk)->icsk_retransmits;
934 	info->mptcpi_bytes_sent = msk->bytes_sent;
935 	info->mptcpi_bytes_received = msk->bytes_received;
936 	info->mptcpi_bytes_retrans = msk->bytes_retrans;
937 	unlock_sock_fast(sk, slow);
938 }
939 EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);
940 
941 static int mptcp_getsockopt_info(struct mptcp_sock *msk, char __user *optval, int __user *optlen)
942 {
943 	struct mptcp_info m_info;
944 	int len;
945 
946 	if (get_user(len, optlen))
947 		return -EFAULT;
948 
949 	len = min_t(unsigned int, len, sizeof(struct mptcp_info));
950 
951 	mptcp_diag_fill_info(msk, &m_info);
952 
953 	if (put_user(len, optlen))
954 		return -EFAULT;
955 
956 	if (copy_to_user(optval, &m_info, len))
957 		return -EFAULT;
958 
959 	return 0;
960 }
961 
962 static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
963 				  char __user *optval,
964 				  u32 copied,
965 				  int __user *optlen)
966 {
967 	u32 copylen = min_t(u32, sfd->size_subflow_data, sizeof(*sfd));
968 
969 	if (copied)
970 		copied += sfd->size_subflow_data;
971 	else
972 		copied = copylen;
973 
974 	if (put_user(copied, optlen))
975 		return -EFAULT;
976 
977 	if (copy_to_user(optval, sfd, copylen))
978 		return -EFAULT;
979 
980 	return 0;
981 }
982 
983 static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
984 				  char __user *optval,
985 				  int __user *optlen)
986 {
987 	int len, copylen;
988 
989 	if (get_user(len, optlen))
990 		return -EFAULT;
991 
992 	/* if mptcp_subflow_data size is changed, need to adjust
993 	 * this function to deal with programs using old version.
994 	 */
995 	BUILD_BUG_ON(sizeof(*sfd) != MIN_INFO_OPTLEN_SIZE);
996 
997 	if (len < MIN_INFO_OPTLEN_SIZE)
998 		return -EINVAL;
999 
1000 	memset(sfd, 0, sizeof(*sfd));
1001 
1002 	copylen = min_t(unsigned int, len, sizeof(*sfd));
1003 	if (copy_from_user(sfd, optval, copylen))
1004 		return -EFAULT;
1005 
1006 	/* size_subflow_data is u32, but len is signed */
1007 	if (sfd->size_subflow_data > INT_MAX ||
1008 	    sfd->size_user > INT_MAX)
1009 		return -EINVAL;
1010 
1011 	if (sfd->size_subflow_data < MIN_INFO_OPTLEN_SIZE ||
1012 	    sfd->size_subflow_data > len)
1013 		return -EINVAL;
1014 
1015 	if (sfd->num_subflows || sfd->size_kernel)
1016 		return -EINVAL;
1017 
1018 	return len - sfd->size_subflow_data;
1019 }
1020 
1021 static int mptcp_getsockopt_tcpinfo(struct mptcp_sock *msk, char __user *optval,
1022 				    int __user *optlen)
1023 {
1024 	struct mptcp_subflow_context *subflow;
1025 	struct sock *sk = (struct sock *)msk;
1026 	unsigned int sfcount = 0, copied = 0;
1027 	struct mptcp_subflow_data sfd;
1028 	char __user *infoptr;
1029 	int len;
1030 
1031 	len = mptcp_get_subflow_data(&sfd, optval, optlen);
1032 	if (len < 0)
1033 		return len;
1034 
1035 	sfd.size_kernel = sizeof(struct tcp_info);
1036 	sfd.size_user = min_t(unsigned int, sfd.size_user,
1037 			      sizeof(struct tcp_info));
1038 
1039 	infoptr = optval + sfd.size_subflow_data;
1040 
1041 	lock_sock(sk);
1042 
1043 	mptcp_for_each_subflow(msk, subflow) {
1044 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1045 
1046 		++sfcount;
1047 
1048 		if (len && len >= sfd.size_user) {
1049 			struct tcp_info info;
1050 
1051 			tcp_get_info(ssk, &info);
1052 
1053 			if (copy_to_user(infoptr, &info, sfd.size_user)) {
1054 				release_sock(sk);
1055 				return -EFAULT;
1056 			}
1057 
1058 			infoptr += sfd.size_user;
1059 			copied += sfd.size_user;
1060 			len -= sfd.size_user;
1061 		}
1062 	}
1063 
1064 	release_sock(sk);
1065 
1066 	sfd.num_subflows = sfcount;
1067 
1068 	if (mptcp_put_subflow_data(&sfd, optval, copied, optlen))
1069 		return -EFAULT;
1070 
1071 	return 0;
1072 }
1073 
1074 static void mptcp_get_sub_addrs(const struct sock *sk, struct mptcp_subflow_addrs *a)
1075 {
1076 	const struct inet_sock *inet = inet_sk(sk);
1077 
1078 	memset(a, 0, sizeof(*a));
1079 
1080 	if (sk->sk_family == AF_INET) {
1081 		a->sin_local.sin_family = AF_INET;
1082 		a->sin_local.sin_port = inet->inet_sport;
1083 		a->sin_local.sin_addr.s_addr = inet->inet_rcv_saddr;
1084 
1085 		if (!a->sin_local.sin_addr.s_addr)
1086 			a->sin_local.sin_addr.s_addr = inet->inet_saddr;
1087 
1088 		a->sin_remote.sin_family = AF_INET;
1089 		a->sin_remote.sin_port = inet->inet_dport;
1090 		a->sin_remote.sin_addr.s_addr = inet->inet_daddr;
1091 #if IS_ENABLED(CONFIG_IPV6)
1092 	} else if (sk->sk_family == AF_INET6) {
1093 		const struct ipv6_pinfo *np = inet6_sk(sk);
1094 
1095 		if (WARN_ON_ONCE(!np))
1096 			return;
1097 
1098 		a->sin6_local.sin6_family = AF_INET6;
1099 		a->sin6_local.sin6_port = inet->inet_sport;
1100 
1101 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
1102 			a->sin6_local.sin6_addr = np->saddr;
1103 		else
1104 			a->sin6_local.sin6_addr = sk->sk_v6_rcv_saddr;
1105 
1106 		a->sin6_remote.sin6_family = AF_INET6;
1107 		a->sin6_remote.sin6_port = inet->inet_dport;
1108 		a->sin6_remote.sin6_addr = sk->sk_v6_daddr;
1109 #endif
1110 	}
1111 }
1112 
1113 static int mptcp_getsockopt_subflow_addrs(struct mptcp_sock *msk, char __user *optval,
1114 					  int __user *optlen)
1115 {
1116 	struct mptcp_subflow_context *subflow;
1117 	struct sock *sk = (struct sock *)msk;
1118 	unsigned int sfcount = 0, copied = 0;
1119 	struct mptcp_subflow_data sfd;
1120 	char __user *addrptr;
1121 	int len;
1122 
1123 	len = mptcp_get_subflow_data(&sfd, optval, optlen);
1124 	if (len < 0)
1125 		return len;
1126 
1127 	sfd.size_kernel = sizeof(struct mptcp_subflow_addrs);
1128 	sfd.size_user = min_t(unsigned int, sfd.size_user,
1129 			      sizeof(struct mptcp_subflow_addrs));
1130 
1131 	addrptr = optval + sfd.size_subflow_data;
1132 
1133 	lock_sock(sk);
1134 
1135 	mptcp_for_each_subflow(msk, subflow) {
1136 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1137 
1138 		++sfcount;
1139 
1140 		if (len && len >= sfd.size_user) {
1141 			struct mptcp_subflow_addrs a;
1142 
1143 			mptcp_get_sub_addrs(ssk, &a);
1144 
1145 			if (copy_to_user(addrptr, &a, sfd.size_user)) {
1146 				release_sock(sk);
1147 				return -EFAULT;
1148 			}
1149 
1150 			addrptr += sfd.size_user;
1151 			copied += sfd.size_user;
1152 			len -= sfd.size_user;
1153 		}
1154 	}
1155 
1156 	release_sock(sk);
1157 
1158 	sfd.num_subflows = sfcount;
1159 
1160 	if (mptcp_put_subflow_data(&sfd, optval, copied, optlen))
1161 		return -EFAULT;
1162 
1163 	return 0;
1164 }
1165 
1166 static int mptcp_get_full_info(struct mptcp_full_info *mfi,
1167 			       char __user *optval,
1168 			       int __user *optlen)
1169 {
1170 	int len;
1171 
1172 	BUILD_BUG_ON(offsetof(struct mptcp_full_info, mptcp_info) !=
1173 		     MIN_FULL_INFO_OPTLEN_SIZE);
1174 
1175 	if (get_user(len, optlen))
1176 		return -EFAULT;
1177 
1178 	if (len < MIN_FULL_INFO_OPTLEN_SIZE)
1179 		return -EINVAL;
1180 
1181 	memset(mfi, 0, sizeof(*mfi));
1182 	if (copy_from_user(mfi, optval, MIN_FULL_INFO_OPTLEN_SIZE))
1183 		return -EFAULT;
1184 
1185 	if (mfi->size_tcpinfo_kernel ||
1186 	    mfi->size_sfinfo_kernel ||
1187 	    mfi->num_subflows)
1188 		return -EINVAL;
1189 
1190 	if (mfi->size_sfinfo_user > INT_MAX ||
1191 	    mfi->size_tcpinfo_user > INT_MAX)
1192 		return -EINVAL;
1193 
1194 	return len - MIN_FULL_INFO_OPTLEN_SIZE;
1195 }
1196 
1197 static int mptcp_put_full_info(struct mptcp_full_info *mfi,
1198 			       char __user *optval,
1199 			       u32 copylen,
1200 			       int __user *optlen)
1201 {
1202 	copylen += MIN_FULL_INFO_OPTLEN_SIZE;
1203 	if (put_user(copylen, optlen))
1204 		return -EFAULT;
1205 
1206 	if (copy_to_user(optval, mfi, copylen))
1207 		return -EFAULT;
1208 	return 0;
1209 }
1210 
1211 static int mptcp_getsockopt_full_info(struct mptcp_sock *msk, char __user *optval,
1212 				      int __user *optlen)
1213 {
1214 	unsigned int sfcount = 0, copylen = 0;
1215 	struct mptcp_subflow_context *subflow;
1216 	struct sock *sk = (struct sock *)msk;
1217 	void __user *tcpinfoptr, *sfinfoptr;
1218 	struct mptcp_full_info mfi;
1219 	int len;
1220 
1221 	len = mptcp_get_full_info(&mfi, optval, optlen);
1222 	if (len < 0)
1223 		return len;
1224 
1225 	/* don't bother filling the mptcp info if there is not enough
1226 	 * user-space-provided storage
1227 	 */
1228 	if (len > 0) {
1229 		mptcp_diag_fill_info(msk, &mfi.mptcp_info);
1230 		copylen += min_t(unsigned int, len, sizeof(struct mptcp_info));
1231 	}
1232 
1233 	mfi.size_tcpinfo_kernel = sizeof(struct tcp_info);
1234 	mfi.size_tcpinfo_user = min_t(unsigned int, mfi.size_tcpinfo_user,
1235 				      sizeof(struct tcp_info));
1236 	sfinfoptr = u64_to_user_ptr(mfi.subflow_info);
1237 	mfi.size_sfinfo_kernel = sizeof(struct mptcp_subflow_info);
1238 	mfi.size_sfinfo_user = min_t(unsigned int, mfi.size_sfinfo_user,
1239 				     sizeof(struct mptcp_subflow_info));
1240 	tcpinfoptr = u64_to_user_ptr(mfi.tcp_info);
1241 
1242 	lock_sock(sk);
1243 	mptcp_for_each_subflow(msk, subflow) {
1244 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1245 		struct mptcp_subflow_info sfinfo;
1246 		struct tcp_info tcp_info;
1247 
1248 		if (sfcount++ >= mfi.size_arrays_user)
1249 			continue;
1250 
1251 		/* fetch addr/tcp_info only if the user space buffers
1252 		 * are wide enough
1253 		 */
1254 		memset(&sfinfo, 0, sizeof(sfinfo));
1255 		sfinfo.id = subflow->subflow_id;
1256 		if (mfi.size_sfinfo_user >
1257 		    offsetof(struct mptcp_subflow_info, addrs))
1258 			mptcp_get_sub_addrs(ssk, &sfinfo.addrs);
1259 		if (copy_to_user(sfinfoptr, &sfinfo, mfi.size_sfinfo_user))
1260 			goto fail_release;
1261 
1262 		if (mfi.size_tcpinfo_user) {
1263 			tcp_get_info(ssk, &tcp_info);
1264 			if (copy_to_user(tcpinfoptr, &tcp_info,
1265 					 mfi.size_tcpinfo_user))
1266 				goto fail_release;
1267 		}
1268 
1269 		tcpinfoptr += mfi.size_tcpinfo_user;
1270 		sfinfoptr += mfi.size_sfinfo_user;
1271 	}
1272 	release_sock(sk);
1273 
1274 	mfi.num_subflows = sfcount;
1275 	if (mptcp_put_full_info(&mfi, optval, copylen, optlen))
1276 		return -EFAULT;
1277 
1278 	return 0;
1279 
1280 fail_release:
1281 	release_sock(sk);
1282 	return -EFAULT;
1283 }
1284 
1285 static int mptcp_put_int_option(struct mptcp_sock *msk, char __user *optval,
1286 				int __user *optlen, int val)
1287 {
1288 	int len;
1289 
1290 	if (get_user(len, optlen))
1291 		return -EFAULT;
1292 	if (len < 0)
1293 		return -EINVAL;
1294 
1295 	if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
1296 		unsigned char ucval = (unsigned char)val;
1297 
1298 		len = 1;
1299 		if (put_user(len, optlen))
1300 			return -EFAULT;
1301 		if (copy_to_user(optval, &ucval, 1))
1302 			return -EFAULT;
1303 	} else {
1304 		len = min_t(unsigned int, len, sizeof(int));
1305 		if (put_user(len, optlen))
1306 			return -EFAULT;
1307 		if (copy_to_user(optval, &val, len))
1308 			return -EFAULT;
1309 	}
1310 
1311 	return 0;
1312 }
1313 
1314 static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
1315 				    char __user *optval, int __user *optlen)
1316 {
1317 	switch (optname) {
1318 	case TCP_ULP:
1319 	case TCP_CONGESTION:
1320 	case TCP_INFO:
1321 	case TCP_CC_INFO:
1322 	case TCP_DEFER_ACCEPT:
1323 	case TCP_FASTOPEN:
1324 	case TCP_FASTOPEN_CONNECT:
1325 	case TCP_FASTOPEN_KEY:
1326 	case TCP_FASTOPEN_NO_COOKIE:
1327 		return mptcp_getsockopt_first_sf_only(msk, SOL_TCP, optname,
1328 						      optval, optlen);
1329 	case TCP_INQ:
1330 		return mptcp_put_int_option(msk, optval, optlen, msk->recvmsg_inq);
1331 	case TCP_CORK:
1332 		return mptcp_put_int_option(msk, optval, optlen, msk->cork);
1333 	case TCP_NODELAY:
1334 		return mptcp_put_int_option(msk, optval, optlen, msk->nodelay);
1335 	}
1336 	return -EOPNOTSUPP;
1337 }
1338 
1339 static int mptcp_getsockopt_v4(struct mptcp_sock *msk, int optname,
1340 			       char __user *optval, int __user *optlen)
1341 {
1342 	struct sock *sk = (void *)msk;
1343 
1344 	switch (optname) {
1345 	case IP_TOS:
1346 		return mptcp_put_int_option(msk, optval, optlen, inet_sk(sk)->tos);
1347 	}
1348 
1349 	return -EOPNOTSUPP;
1350 }
1351 
1352 static int mptcp_getsockopt_sol_mptcp(struct mptcp_sock *msk, int optname,
1353 				      char __user *optval, int __user *optlen)
1354 {
1355 	switch (optname) {
1356 	case MPTCP_INFO:
1357 		return mptcp_getsockopt_info(msk, optval, optlen);
1358 	case MPTCP_FULL_INFO:
1359 		return mptcp_getsockopt_full_info(msk, optval, optlen);
1360 	case MPTCP_TCPINFO:
1361 		return mptcp_getsockopt_tcpinfo(msk, optval, optlen);
1362 	case MPTCP_SUBFLOW_ADDRS:
1363 		return mptcp_getsockopt_subflow_addrs(msk, optval, optlen);
1364 	}
1365 
1366 	return -EOPNOTSUPP;
1367 }
1368 
1369 int mptcp_getsockopt(struct sock *sk, int level, int optname,
1370 		     char __user *optval, int __user *option)
1371 {
1372 	struct mptcp_sock *msk = mptcp_sk(sk);
1373 	struct sock *ssk;
1374 
1375 	pr_debug("msk=%p", msk);
1376 
1377 	/* @@ the meaning of setsockopt() when the socket is connected and
1378 	 * there are multiple subflows is not yet defined. It is up to the
1379 	 * MPTCP-level socket to configure the subflows until the subflow
1380 	 * is in TCP fallback, when socket options are passed through
1381 	 * to the one remaining subflow.
1382 	 */
1383 	lock_sock(sk);
1384 	ssk = __mptcp_tcp_fallback(msk);
1385 	release_sock(sk);
1386 	if (ssk)
1387 		return tcp_getsockopt(ssk, level, optname, optval, option);
1388 
1389 	if (level == SOL_IP)
1390 		return mptcp_getsockopt_v4(msk, optname, optval, option);
1391 	if (level == SOL_TCP)
1392 		return mptcp_getsockopt_sol_tcp(msk, optname, optval, option);
1393 	if (level == SOL_MPTCP)
1394 		return mptcp_getsockopt_sol_mptcp(msk, optname, optval, option);
1395 	return -EOPNOTSUPP;
1396 }
1397 
1398 static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
1399 {
1400 	static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
1401 	struct sock *sk = (struct sock *)msk;
1402 
1403 	if (ssk->sk_prot->keepalive) {
1404 		if (sock_flag(sk, SOCK_KEEPOPEN))
1405 			ssk->sk_prot->keepalive(ssk, 1);
1406 		else
1407 			ssk->sk_prot->keepalive(ssk, 0);
1408 	}
1409 
1410 	ssk->sk_priority = sk->sk_priority;
1411 	ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
1412 	ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
1413 	ssk->sk_ipv6only = sk->sk_ipv6only;
1414 	__ip_sock_set_tos(ssk, inet_sk(sk)->tos);
1415 
1416 	if (sk->sk_userlocks & tx_rx_locks) {
1417 		ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
1418 		if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
1419 			WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
1420 		if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1421 			WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
1422 	}
1423 
1424 	if (sock_flag(sk, SOCK_LINGER)) {
1425 		ssk->sk_lingertime = sk->sk_lingertime;
1426 		sock_set_flag(ssk, SOCK_LINGER);
1427 	} else {
1428 		sock_reset_flag(ssk, SOCK_LINGER);
1429 	}
1430 
1431 	if (sk->sk_mark != ssk->sk_mark) {
1432 		ssk->sk_mark = sk->sk_mark;
1433 		sk_dst_reset(ssk);
1434 	}
1435 
1436 	sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
1437 
1438 	if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
1439 		tcp_set_congestion_control(ssk, msk->ca_name, false, true);
1440 	__tcp_sock_set_cork(ssk, !!msk->cork);
1441 	__tcp_sock_set_nodelay(ssk, !!msk->nodelay);
1442 
1443 	inet_assign_bit(TRANSPARENT, ssk, inet_test_bit(TRANSPARENT, sk));
1444 	inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
1445 }
1446 
1447 static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
1448 {
1449 	bool slow = lock_sock_fast(ssk);
1450 
1451 	sync_socket_options(msk, ssk);
1452 
1453 	unlock_sock_fast(ssk, slow);
1454 }
1455 
1456 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
1457 {
1458 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1459 
1460 	msk_owned_by_me(msk);
1461 
1462 	if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
1463 		__mptcp_sockopt_sync(msk, ssk);
1464 
1465 		subflow->setsockopt_seq = msk->setsockopt_seq;
1466 	}
1467 }
1468 
1469 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk)
1470 {
1471 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1472 
1473 	msk_owned_by_me(msk);
1474 
1475 	if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
1476 		sync_socket_options(msk, ssk);
1477 
1478 		subflow->setsockopt_seq = msk->setsockopt_seq;
1479 	}
1480 }
1481