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
__mptcp_tcp_fallback(struct mptcp_sock * msk)17 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
18 {
19 sock_owned_by_me((const struct sock *)msk);
20
21 if (likely(!__mptcp_check_fallback(msk)))
22 return NULL;
23
24 return msk->first;
25 }
26
sockopt_seq_reset(const struct sock * sk)27 static u32 sockopt_seq_reset(const struct sock *sk)
28 {
29 sock_owned_by_me(sk);
30
31 /* Highbits contain state. Allows to distinguish sockopt_seq
32 * of listener and established:
33 * s0 = new_listener()
34 * sockopt(s0) - seq is 1
35 * s1 = accept(s0) - s1 inherits seq 1 if listener sk (s0)
36 * sockopt(s0) - seq increments to 2 on s0
37 * sockopt(s1) // seq increments to 2 on s1 (different option)
38 * new ssk completes join, inherits options from s0 // seq 2
39 * Needs sync from mptcp join logic, but ssk->seq == msk->seq
40 *
41 * Set High order bits to sk_state so ssk->seq == msk->seq test
42 * will fail.
43 */
44
45 return (u32)sk->sk_state << 24u;
46 }
47
sockopt_seq_inc(struct mptcp_sock * msk)48 static void sockopt_seq_inc(struct mptcp_sock *msk)
49 {
50 u32 seq = (msk->setsockopt_seq + 1) & 0x00ffffff;
51
52 msk->setsockopt_seq = sockopt_seq_reset((struct sock *)msk) + seq;
53 }
54
mptcp_get_int_option(struct mptcp_sock * msk,sockptr_t optval,unsigned int optlen,int * val)55 static int mptcp_get_int_option(struct mptcp_sock *msk, sockptr_t optval,
56 unsigned int optlen, int *val)
57 {
58 if (optlen < sizeof(int))
59 return -EINVAL;
60
61 if (copy_from_sockptr(val, optval, sizeof(*val)))
62 return -EFAULT;
63
64 return 0;
65 }
66
mptcp_sol_socket_sync_intval(struct mptcp_sock * msk,int optname,int val)67 static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, int val)
68 {
69 struct mptcp_subflow_context *subflow;
70 struct sock *sk = (struct sock *)msk;
71
72 lock_sock(sk);
73 sockopt_seq_inc(msk);
74
75 mptcp_for_each_subflow(msk, subflow) {
76 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
77 bool slow = lock_sock_fast(ssk);
78
79 switch (optname) {
80 case SO_DEBUG:
81 sock_valbool_flag(ssk, SOCK_DBG, !!val);
82 break;
83 case SO_KEEPALIVE:
84 if (ssk->sk_prot->keepalive)
85 ssk->sk_prot->keepalive(ssk, !!val);
86 sock_valbool_flag(ssk, SOCK_KEEPOPEN, !!val);
87 break;
88 case SO_PRIORITY:
89 ssk->sk_priority = val;
90 break;
91 case SO_SNDBUF:
92 case SO_SNDBUFFORCE:
93 ssk->sk_userlocks |= SOCK_SNDBUF_LOCK;
94 WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
95 break;
96 case SO_RCVBUF:
97 case SO_RCVBUFFORCE:
98 ssk->sk_userlocks |= SOCK_RCVBUF_LOCK;
99 WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
100 break;
101 case SO_MARK:
102 if (READ_ONCE(ssk->sk_mark) != sk->sk_mark) {
103 ssk->sk_mark = sk->sk_mark;
104 sk_dst_reset(ssk);
105 }
106 break;
107 case SO_INCOMING_CPU:
108 WRITE_ONCE(ssk->sk_incoming_cpu, val);
109 break;
110 }
111
112 subflow->setsockopt_seq = msk->setsockopt_seq;
113 unlock_sock_fast(ssk, slow);
114 }
115
116 release_sock(sk);
117 }
118
mptcp_sol_socket_intval(struct mptcp_sock * msk,int optname,int val)119 static int mptcp_sol_socket_intval(struct mptcp_sock *msk, int optname, int val)
120 {
121 sockptr_t optval = KERNEL_SOCKPTR(&val);
122 struct sock *sk = (struct sock *)msk;
123 int ret;
124
125 ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
126 optval, sizeof(val));
127 if (ret)
128 return ret;
129
130 mptcp_sol_socket_sync_intval(msk, optname, val);
131 return 0;
132 }
133
mptcp_so_incoming_cpu(struct mptcp_sock * msk,int val)134 static void mptcp_so_incoming_cpu(struct mptcp_sock *msk, int val)
135 {
136 struct sock *sk = (struct sock *)msk;
137
138 WRITE_ONCE(sk->sk_incoming_cpu, val);
139
140 mptcp_sol_socket_sync_intval(msk, SO_INCOMING_CPU, val);
141 }
142
mptcp_setsockopt_sol_socket_int(struct mptcp_sock * msk,int optname,sockptr_t optval,unsigned int optlen)143 static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
144 sockptr_t optval, unsigned int optlen)
145 {
146 int val, ret;
147
148 ret = mptcp_get_int_option(msk, optval, optlen, &val);
149 if (ret)
150 return ret;
151
152 switch (optname) {
153 case SO_KEEPALIVE:
154 mptcp_sol_socket_sync_intval(msk, optname, val);
155 return 0;
156 case SO_DEBUG:
157 case SO_MARK:
158 case SO_PRIORITY:
159 case SO_SNDBUF:
160 case SO_SNDBUFFORCE:
161 case SO_RCVBUF:
162 case SO_RCVBUFFORCE:
163 return mptcp_sol_socket_intval(msk, optname, val);
164 case SO_INCOMING_CPU:
165 mptcp_so_incoming_cpu(msk, val);
166 return 0;
167 }
168
169 return -ENOPROTOOPT;
170 }
171
mptcp_setsockopt_sol_socket_linger(struct mptcp_sock * msk,sockptr_t optval,unsigned int optlen)172 static int mptcp_setsockopt_sol_socket_linger(struct mptcp_sock *msk, sockptr_t optval,
173 unsigned int optlen)
174 {
175 struct mptcp_subflow_context *subflow;
176 struct sock *sk = (struct sock *)msk;
177 struct linger ling;
178 sockptr_t kopt;
179 int ret;
180
181 if (optlen < sizeof(ling))
182 return -EINVAL;
183
184 if (copy_from_sockptr(&ling, optval, sizeof(ling)))
185 return -EFAULT;
186
187 kopt = KERNEL_SOCKPTR(&ling);
188 ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, SO_LINGER, kopt, sizeof(ling));
189 if (ret)
190 return ret;
191
192 lock_sock(sk);
193 sockopt_seq_inc(msk);
194 mptcp_for_each_subflow(msk, subflow) {
195 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
196 bool slow = lock_sock_fast(ssk);
197
198 if (!ling.l_onoff) {
199 sock_reset_flag(ssk, SOCK_LINGER);
200 } else {
201 ssk->sk_lingertime = sk->sk_lingertime;
202 sock_set_flag(ssk, SOCK_LINGER);
203 }
204
205 subflow->setsockopt_seq = msk->setsockopt_seq;
206 unlock_sock_fast(ssk, slow);
207 }
208
209 release_sock(sk);
210 return 0;
211 }
212
mptcp_setsockopt_sol_socket(struct mptcp_sock * msk,int optname,sockptr_t optval,unsigned int optlen)213 static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
214 sockptr_t optval, unsigned int optlen)
215 {
216 struct sock *sk = (struct sock *)msk;
217 struct socket *ssock;
218 int ret;
219
220 switch (optname) {
221 case SO_REUSEPORT:
222 case SO_REUSEADDR:
223 case SO_BINDTODEVICE:
224 case SO_BINDTOIFINDEX:
225 lock_sock(sk);
226 ssock = __mptcp_nmpc_socket(msk);
227 if (!ssock) {
228 release_sock(sk);
229 return -EINVAL;
230 }
231
232 ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
233 if (ret == 0) {
234 if (optname == SO_REUSEPORT)
235 sk->sk_reuseport = ssock->sk->sk_reuseport;
236 else if (optname == SO_REUSEADDR)
237 sk->sk_reuse = ssock->sk->sk_reuse;
238 else if (optname == SO_BINDTODEVICE)
239 sk->sk_bound_dev_if = ssock->sk->sk_bound_dev_if;
240 else if (optname == SO_BINDTOIFINDEX)
241 sk->sk_bound_dev_if = ssock->sk->sk_bound_dev_if;
242 }
243 release_sock(sk);
244 return ret;
245 case SO_KEEPALIVE:
246 case SO_PRIORITY:
247 case SO_SNDBUF:
248 case SO_SNDBUFFORCE:
249 case SO_RCVBUF:
250 case SO_RCVBUFFORCE:
251 case SO_MARK:
252 case SO_INCOMING_CPU:
253 case SO_DEBUG:
254 return mptcp_setsockopt_sol_socket_int(msk, optname, optval, optlen);
255 case SO_LINGER:
256 return mptcp_setsockopt_sol_socket_linger(msk, optval, optlen);
257 case SO_NO_CHECK:
258 case SO_DONTROUTE:
259 case SO_BROADCAST:
260 case SO_BSDCOMPAT:
261 case SO_PASSCRED:
262 case SO_PASSSEC:
263 case SO_RXQ_OVFL:
264 case SO_WIFI_STATUS:
265 case SO_NOFCS:
266 case SO_SELECT_ERR_QUEUE:
267 return 0;
268 }
269
270 return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
271 }
272
mptcp_setsockopt_v6(struct mptcp_sock * msk,int optname,sockptr_t optval,unsigned int optlen)273 static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
274 sockptr_t optval, unsigned int optlen)
275 {
276 struct sock *sk = (struct sock *)msk;
277 int ret = -EOPNOTSUPP;
278 struct socket *ssock;
279
280 switch (optname) {
281 case IPV6_V6ONLY:
282 lock_sock(sk);
283 ssock = __mptcp_nmpc_socket(msk);
284 if (!ssock) {
285 release_sock(sk);
286 return -EINVAL;
287 }
288
289 ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
290 if (ret == 0)
291 sk->sk_ipv6only = ssock->sk->sk_ipv6only;
292
293 release_sock(sk);
294 break;
295 }
296
297 return ret;
298 }
299
mptcp_supported_sockopt(int level,int optname)300 static bool mptcp_supported_sockopt(int level, int optname)
301 {
302 if (level == SOL_SOCKET) {
303 switch (optname) {
304 case SO_DEBUG:
305 case SO_REUSEPORT:
306 case SO_REUSEADDR:
307
308 /* the following ones need a better implementation,
309 * but are quite common we want to preserve them
310 */
311 case SO_BINDTODEVICE:
312 case SO_SNDBUF:
313 case SO_SNDBUFFORCE:
314 case SO_RCVBUF:
315 case SO_RCVBUFFORCE:
316 case SO_KEEPALIVE:
317 case SO_PRIORITY:
318 case SO_LINGER:
319 case SO_TIMESTAMP_OLD:
320 case SO_TIMESTAMP_NEW:
321 case SO_TIMESTAMPNS_OLD:
322 case SO_TIMESTAMPNS_NEW:
323 case SO_TIMESTAMPING_OLD:
324 case SO_TIMESTAMPING_NEW:
325 case SO_RCVLOWAT:
326 case SO_RCVTIMEO_OLD:
327 case SO_RCVTIMEO_NEW:
328 case SO_SNDTIMEO_OLD:
329 case SO_SNDTIMEO_NEW:
330 case SO_MARK:
331 case SO_INCOMING_CPU:
332 case SO_BINDTOIFINDEX:
333 case SO_BUSY_POLL:
334 case SO_PREFER_BUSY_POLL:
335 case SO_BUSY_POLL_BUDGET:
336
337 /* next ones are no-op for plain TCP */
338 case SO_NO_CHECK:
339 case SO_DONTROUTE:
340 case SO_BROADCAST:
341 case SO_BSDCOMPAT:
342 case SO_PASSCRED:
343 case SO_PASSSEC:
344 case SO_RXQ_OVFL:
345 case SO_WIFI_STATUS:
346 case SO_NOFCS:
347 case SO_SELECT_ERR_QUEUE:
348 return true;
349 }
350
351 /* SO_OOBINLINE is not supported, let's avoid the related mess */
352 /* SO_ATTACH_FILTER, SO_ATTACH_BPF, SO_ATTACH_REUSEPORT_CBPF,
353 * SO_DETACH_REUSEPORT_BPF, SO_DETACH_FILTER, SO_LOCK_FILTER,
354 * we must be careful with subflows
355 */
356 /* SO_ATTACH_REUSEPORT_EBPF is not supported, at it checks
357 * explicitly the sk_protocol field
358 */
359 /* SO_PEEK_OFF is unsupported, as it is for plain TCP */
360 /* SO_MAX_PACING_RATE is unsupported, we must be careful with subflows */
361 /* SO_CNX_ADVICE is currently unsupported, could possibly be relevant,
362 * but likely needs careful design
363 */
364 /* SO_ZEROCOPY is currently unsupported, TODO in sndmsg */
365 /* SO_TXTIME is currently unsupported */
366 return false;
367 }
368 if (level == SOL_IP) {
369 switch (optname) {
370 /* should work fine */
371 case IP_FREEBIND:
372 case IP_TRANSPARENT:
373
374 /* the following are control cmsg related */
375 case IP_PKTINFO:
376 case IP_RECVTTL:
377 case IP_RECVTOS:
378 case IP_RECVOPTS:
379 case IP_RETOPTS:
380 case IP_PASSSEC:
381 case IP_RECVORIGDSTADDR:
382 case IP_CHECKSUM:
383 case IP_RECVFRAGSIZE:
384
385 /* common stuff that need some love */
386 case IP_TOS:
387 case IP_TTL:
388 case IP_BIND_ADDRESS_NO_PORT:
389 case IP_MTU_DISCOVER:
390 case IP_RECVERR:
391
392 /* possibly less common may deserve some love */
393 case IP_MINTTL:
394
395 /* the following is apparently a no-op for plain TCP */
396 case IP_RECVERR_RFC4884:
397 return true;
398 }
399
400 /* IP_OPTIONS is not supported, needs subflow care */
401 /* IP_HDRINCL, IP_NODEFRAG are not supported, RAW specific */
402 /* IP_MULTICAST_TTL, IP_MULTICAST_LOOP, IP_UNICAST_IF,
403 * IP_ADD_MEMBERSHIP, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_MEMBERSHIP,
404 * IP_DROP_SOURCE_MEMBERSHIP, IP_BLOCK_SOURCE, IP_UNBLOCK_SOURCE,
405 * MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP MCAST_JOIN_SOURCE_GROUP,
406 * MCAST_LEAVE_SOURCE_GROUP, MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE,
407 * MCAST_MSFILTER, IP_MULTICAST_ALL are not supported, better not deal
408 * with mcast stuff
409 */
410 /* IP_IPSEC_POLICY, IP_XFRM_POLICY are nut supported, unrelated here */
411 return false;
412 }
413 if (level == SOL_IPV6) {
414 switch (optname) {
415 case IPV6_V6ONLY:
416
417 /* the following are control cmsg related */
418 case IPV6_RECVPKTINFO:
419 case IPV6_2292PKTINFO:
420 case IPV6_RECVHOPLIMIT:
421 case IPV6_2292HOPLIMIT:
422 case IPV6_RECVRTHDR:
423 case IPV6_2292RTHDR:
424 case IPV6_RECVHOPOPTS:
425 case IPV6_2292HOPOPTS:
426 case IPV6_RECVDSTOPTS:
427 case IPV6_2292DSTOPTS:
428 case IPV6_RECVTCLASS:
429 case IPV6_FLOWINFO:
430 case IPV6_RECVPATHMTU:
431 case IPV6_RECVORIGDSTADDR:
432 case IPV6_RECVFRAGSIZE:
433
434 /* the following ones need some love but are quite common */
435 case IPV6_TCLASS:
436 case IPV6_TRANSPARENT:
437 case IPV6_FREEBIND:
438 case IPV6_PKTINFO:
439 case IPV6_2292PKTOPTIONS:
440 case IPV6_UNICAST_HOPS:
441 case IPV6_MTU_DISCOVER:
442 case IPV6_MTU:
443 case IPV6_RECVERR:
444 case IPV6_FLOWINFO_SEND:
445 case IPV6_FLOWLABEL_MGR:
446 case IPV6_MINHOPCOUNT:
447 case IPV6_DONTFRAG:
448 case IPV6_AUTOFLOWLABEL:
449
450 /* the following one is a no-op for plain TCP */
451 case IPV6_RECVERR_RFC4884:
452 return true;
453 }
454
455 /* IPV6_HOPOPTS, IPV6_RTHDRDSTOPTS, IPV6_RTHDR, IPV6_DSTOPTS are
456 * not supported
457 */
458 /* IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_IF,
459 * IPV6_MULTICAST_IF, IPV6_ADDRFORM,
460 * IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_JOIN_ANYCAST,
461 * IPV6_LEAVE_ANYCAST, IPV6_MULTICAST_ALL, MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP,
462 * MCAST_JOIN_SOURCE_GROUP, MCAST_LEAVE_SOURCE_GROUP,
463 * MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE, MCAST_MSFILTER
464 * are not supported better not deal with mcast
465 */
466 /* IPV6_ROUTER_ALERT, IPV6_ROUTER_ALERT_ISOLATE are not supported, since are evil */
467
468 /* IPV6_IPSEC_POLICY, IPV6_XFRM_POLICY are not supported */
469 /* IPV6_ADDR_PREFERENCES is not supported, we must be careful with subflows */
470 return false;
471 }
472 if (level == SOL_TCP) {
473 switch (optname) {
474 /* the following are no-op or should work just fine */
475 case TCP_THIN_DUPACK:
476 case TCP_DEFER_ACCEPT:
477
478 /* the following need some love */
479 case TCP_MAXSEG:
480 case TCP_NODELAY:
481 case TCP_THIN_LINEAR_TIMEOUTS:
482 case TCP_CONGESTION:
483 case TCP_ULP:
484 case TCP_CORK:
485 case TCP_KEEPIDLE:
486 case TCP_KEEPINTVL:
487 case TCP_KEEPCNT:
488 case TCP_SYNCNT:
489 case TCP_SAVE_SYN:
490 case TCP_LINGER2:
491 case TCP_WINDOW_CLAMP:
492 case TCP_QUICKACK:
493 case TCP_USER_TIMEOUT:
494 case TCP_TIMESTAMP:
495 case TCP_NOTSENT_LOWAT:
496 case TCP_TX_DELAY:
497 return true;
498 }
499
500 /* TCP_MD5SIG, TCP_MD5SIG_EXT are not supported, MD5 is not compatible with MPTCP */
501
502 /* TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS,
503 * TCP_REPAIR_WINDOW are not supported, better avoid this mess
504 */
505 /* TCP_FASTOPEN_KEY, TCP_FASTOPEN TCP_FASTOPEN_CONNECT, TCP_FASTOPEN_NO_COOKIE,
506 * are not supported fastopen is currently unsupported
507 */
508 /* TCP_INQ is currently unsupported, needs some recvmsg work */
509 }
510 return false;
511 }
512
mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock * msk,sockptr_t optval,unsigned int optlen)513 static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t optval,
514 unsigned int optlen)
515 {
516 struct mptcp_subflow_context *subflow;
517 struct sock *sk = (struct sock *)msk;
518 char name[TCP_CA_NAME_MAX];
519 bool cap_net_admin;
520 int ret;
521
522 if (optlen < 1)
523 return -EINVAL;
524
525 ret = strncpy_from_sockptr(name, optval,
526 min_t(long, TCP_CA_NAME_MAX - 1, optlen));
527 if (ret < 0)
528 return -EFAULT;
529
530 name[ret] = 0;
531
532 cap_net_admin = ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN);
533
534 ret = 0;
535 lock_sock(sk);
536 sockopt_seq_inc(msk);
537 mptcp_for_each_subflow(msk, subflow) {
538 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
539 int err;
540
541 lock_sock(ssk);
542 err = tcp_set_congestion_control(ssk, name, true, cap_net_admin);
543 if (err < 0 && ret == 0)
544 ret = err;
545 subflow->setsockopt_seq = msk->setsockopt_seq;
546 release_sock(ssk);
547 }
548
549 if (ret == 0)
550 tcp_set_congestion_control(sk, name, false, cap_net_admin);
551
552 release_sock(sk);
553 return ret;
554 }
555
mptcp_setsockopt_sol_tcp(struct mptcp_sock * msk,int optname,sockptr_t optval,unsigned int optlen)556 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
557 sockptr_t optval, unsigned int optlen)
558 {
559 switch (optname) {
560 case TCP_ULP:
561 return -EOPNOTSUPP;
562 case TCP_CONGESTION:
563 return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen);
564 }
565
566 return -EOPNOTSUPP;
567 }
568
mptcp_setsockopt(struct sock * sk,int level,int optname,sockptr_t optval,unsigned int optlen)569 int mptcp_setsockopt(struct sock *sk, int level, int optname,
570 sockptr_t optval, unsigned int optlen)
571 {
572 struct mptcp_sock *msk = mptcp_sk(sk);
573 struct sock *ssk;
574
575 pr_debug("msk=%p", msk);
576
577 if (!mptcp_supported_sockopt(level, optname))
578 return -ENOPROTOOPT;
579
580 if (level == SOL_SOCKET)
581 return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
582
583 /* @@ the meaning of setsockopt() when the socket is connected and
584 * there are multiple subflows is not yet defined. It is up to the
585 * MPTCP-level socket to configure the subflows until the subflow
586 * is in TCP fallback, when TCP socket options are passed through
587 * to the one remaining subflow.
588 */
589 lock_sock(sk);
590 ssk = __mptcp_tcp_fallback(msk);
591 release_sock(sk);
592 if (ssk)
593 return tcp_setsockopt(ssk, level, optname, optval, optlen);
594
595 if (level == SOL_IPV6)
596 return mptcp_setsockopt_v6(msk, optname, optval, optlen);
597
598 if (level == SOL_TCP)
599 return mptcp_setsockopt_sol_tcp(msk, optname, optval, optlen);
600
601 return -EOPNOTSUPP;
602 }
603
mptcp_getsockopt_first_sf_only(struct mptcp_sock * msk,int level,int optname,char __user * optval,int __user * optlen)604 static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
605 char __user *optval, int __user *optlen)
606 {
607 struct sock *sk = (struct sock *)msk;
608 struct socket *ssock;
609 int ret = -EINVAL;
610 struct sock *ssk;
611
612 lock_sock(sk);
613 ssk = msk->first;
614 if (ssk) {
615 ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
616 goto out;
617 }
618
619 ssock = __mptcp_nmpc_socket(msk);
620 if (!ssock)
621 goto out;
622
623 ret = tcp_getsockopt(ssock->sk, level, optname, optval, optlen);
624
625 out:
626 release_sock(sk);
627 return ret;
628 }
629
mptcp_getsockopt_sol_tcp(struct mptcp_sock * msk,int optname,char __user * optval,int __user * optlen)630 static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
631 char __user *optval, int __user *optlen)
632 {
633 switch (optname) {
634 case TCP_ULP:
635 case TCP_CONGESTION:
636 case TCP_INFO:
637 case TCP_CC_INFO:
638 return mptcp_getsockopt_first_sf_only(msk, SOL_TCP, optname,
639 optval, optlen);
640 }
641 return -EOPNOTSUPP;
642 }
643
mptcp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * option)644 int mptcp_getsockopt(struct sock *sk, int level, int optname,
645 char __user *optval, int __user *option)
646 {
647 struct mptcp_sock *msk = mptcp_sk(sk);
648 struct sock *ssk;
649
650 pr_debug("msk=%p", msk);
651
652 /* @@ the meaning of setsockopt() when the socket is connected and
653 * there are multiple subflows is not yet defined. It is up to the
654 * MPTCP-level socket to configure the subflows until the subflow
655 * is in TCP fallback, when socket options are passed through
656 * to the one remaining subflow.
657 */
658 lock_sock(sk);
659 ssk = __mptcp_tcp_fallback(msk);
660 release_sock(sk);
661 if (ssk)
662 return tcp_getsockopt(ssk, level, optname, optval, option);
663
664 if (level == SOL_TCP)
665 return mptcp_getsockopt_sol_tcp(msk, optname, optval, option);
666 return -EOPNOTSUPP;
667 }
668
sync_socket_options(struct mptcp_sock * msk,struct sock * ssk)669 static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
670 {
671 static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
672 struct sock *sk = (struct sock *)msk;
673
674 if (ssk->sk_prot->keepalive) {
675 if (sock_flag(sk, SOCK_KEEPOPEN))
676 ssk->sk_prot->keepalive(ssk, 1);
677 else
678 ssk->sk_prot->keepalive(ssk, 0);
679 }
680
681 ssk->sk_priority = sk->sk_priority;
682 ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
683 ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
684
685 if (sk->sk_userlocks & tx_rx_locks) {
686 ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
687 if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
688 WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
689 if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
690 WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
691 }
692
693 if (sock_flag(sk, SOCK_LINGER)) {
694 ssk->sk_lingertime = sk->sk_lingertime;
695 sock_set_flag(ssk, SOCK_LINGER);
696 } else {
697 sock_reset_flag(ssk, SOCK_LINGER);
698 }
699
700 if (sk->sk_mark != ssk->sk_mark) {
701 ssk->sk_mark = sk->sk_mark;
702 sk_dst_reset(ssk);
703 }
704
705 sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
706
707 if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
708 tcp_set_congestion_control(ssk, inet_csk(sk)->icsk_ca_ops->name, false, true);
709 }
710
__mptcp_sockopt_sync(struct mptcp_sock * msk,struct sock * ssk)711 static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
712 {
713 bool slow = lock_sock_fast(ssk);
714
715 sync_socket_options(msk, ssk);
716
717 unlock_sock_fast(ssk, slow);
718 }
719
mptcp_sockopt_sync(struct mptcp_sock * msk,struct sock * ssk)720 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
721 {
722 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
723
724 msk_owned_by_me(msk);
725
726 if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
727 __mptcp_sockopt_sync(msk, ssk);
728
729 subflow->setsockopt_seq = msk->setsockopt_seq;
730 }
731 }
732
mptcp_sockopt_sync_all(struct mptcp_sock * msk)733 void mptcp_sockopt_sync_all(struct mptcp_sock *msk)
734 {
735 struct mptcp_subflow_context *subflow;
736 struct sock *sk = (struct sock *)msk;
737 u32 seq;
738
739 seq = sockopt_seq_reset(sk);
740
741 mptcp_for_each_subflow(msk, subflow) {
742 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
743 u32 sseq = READ_ONCE(subflow->setsockopt_seq);
744
745 if (sseq != msk->setsockopt_seq) {
746 __mptcp_sockopt_sync(msk, ssk);
747 WRITE_ONCE(subflow->setsockopt_seq, seq);
748 } else if (sseq != seq) {
749 WRITE_ONCE(subflow->setsockopt_seq, seq);
750 }
751
752 cond_resched();
753 }
754
755 msk->setsockopt_seq = seq;
756 }
757