1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* INET An implementation of the TCP/IP protocol suite for the LINUX
4	* operating system. INET is implemented using the BSD Socket
5	* interface as the means of communication with the user level.
6	*
7	* Implementation of the Transmission Control Protocol(TCP).
8	*
9	* Authors: Ross Biro
10	* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11	* Mark Evans, <evansmp@uhura.aston.ac.uk>
12	* Corey Minyard <wf-rch!minyard@relay.EU.net>
13	* Florian La Roche, <flla@stud.uni-sb.de>
14	* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
15	* Linus Torvalds, <torvalds@cs.helsinki.fi>
16	* Alan Cox, <gw4pts@gw4pts.ampr.org>
17	* Matthew Dillon, <dillon@apollo.west.oic.com>
18	* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
19	* Jorge Cwik, <jorge@laser.satlink.net>
20	*
21	* Fixes:
22	* Alan Cox : Numerous verify_area() calls
23	* Alan Cox : Set the ACK bit on a reset
24	* Alan Cox : Stopped it crashing if it closed while
25	* sk->inuse=1 and was trying to connect
26	* (tcp_err()).
27	* Alan Cox : All icmp error handling was broken
28	* pointers passed where wrong and the
29	* socket was looked up backwards. Nobody
30	* tested any icmp error code obviously.
31	* Alan Cox : tcp_err() now handled properly. It
32	* wakes people on errors. poll
33	* behaves and the icmp error race
34	* has gone by moving it into sock.c
35	* Alan Cox : tcp_send_reset() fixed to work for
36	* everything not just packets for
37	* unknown sockets.
38	* Alan Cox : tcp option processing.
39	* Alan Cox : Reset tweaked (still not 100%) [Had
40	* syn rule wrong]
41	* Herp Rosmanith : More reset fixes
42	* Alan Cox : No longer acks invalid rst frames.
43	* Acking any kind of RST is right out.
44	* Alan Cox : Sets an ignore me flag on an rst
45	* receive otherwise odd bits of prattle
46	* escape still
47	* Alan Cox : Fixed another acking RST frame bug.
48	* Should stop LAN workplace lockups.
49	* Alan Cox : Some tidyups using the new skb list
50	* facilities
51	* Alan Cox : sk->keepopen now seems to work
52	* Alan Cox : Pulls options out correctly on accepts
53	* Alan Cox : Fixed assorted sk->rqueue->next errors
54	* Alan Cox : PSH doesn't end a TCP read. Switched a
55	* bit to skb ops.
56	* Alan Cox : Tidied tcp_data to avoid a potential
57	* nasty.
58	* Alan Cox : Added some better commenting, as the
59	* tcp is hard to follow
60	* Alan Cox : Removed incorrect check for 20 * psh
61	* Michael O'Reilly : ack < copied bug fix.
62	* Johannes Stille : Misc tcp fixes (not all in yet).
63	* Alan Cox : FIN with no memory -> CRASH
64	* Alan Cox : Added socket option proto entries.
65	* Also added awareness of them to accept.
66	* Alan Cox : Added TCP options (SOL_TCP)
67	* Alan Cox : Switched wakeup calls to callbacks,
68	* so the kernel can layer network
69	* sockets.
70	* Alan Cox : Use ip_tos/ip_ttl settings.
71	* Alan Cox : Handle FIN (more) properly (we hope).
72	* Alan Cox : RST frames sent on unsynchronised
73	* state ack error.
74	* Alan Cox : Put in missing check for SYN bit.
75	* Alan Cox : Added tcp_select_window() aka NET2E
76	* window non shrink trick.
77	* Alan Cox : Added a couple of small NET2E timer
78	* fixes
79	* Charles Hedrick : TCP fixes
80	* Toomas Tamm : TCP window fixes
81	* Alan Cox : Small URG fix to rlogin ^C ack fight
82	* Charles Hedrick : Rewrote most of it to actually work
83	* Linus : Rewrote tcp_read() and URG handling
84	* completely
85	* Gerhard Koerting: Fixed some missing timer handling
86	* Matthew Dillon : Reworked TCP machine states as per RFC
87	* Gerhard Koerting: PC/TCP workarounds
88	* Adam Caldwell : Assorted timer/timing errors
89	* Matthew Dillon : Fixed another RST bug
90	* Alan Cox : Move to kernel side addressing changes.
91	* Alan Cox : Beginning work on TCP fastpathing
92	* (not yet usable)
93	* Arnt Gulbrandsen: Turbocharged tcp_check() routine.
94	* Alan Cox : TCP fast path debugging
95	* Alan Cox : Window clamping
96	* Michael Riepe : Bug in tcp_check()
97	* Matt Dillon : More TCP improvements and RST bug fixes
98	* Matt Dillon : Yet more small nasties remove from the
99	* TCP code (Be very nice to this man if
100	* tcp finally works 100%) 8)
101	* Alan Cox : BSD accept semantics.
102	* Alan Cox : Reset on closedown bug.
103	* Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
104	* Michael Pall : Handle poll() after URG properly in
105	* all cases.
106	* Michael Pall : Undo the last fix in tcp_read_urg()
107	* (multi URG PUSH broke rlogin).
108	* Michael Pall : Fix the multi URG PUSH problem in
109	* tcp_readable(), poll() after URG
110	* works now.
111	* Michael Pall : recv(...,MSG_OOB) never blocks in the
112	* BSD api.
113	* Alan Cox : Changed the semantics of sk->socket to
114	* fix a race and a signal problem with
115	* accept() and async I/O.
116	* Alan Cox : Relaxed the rules on tcp_sendto().
117	* Yury Shevchuk : Really fixed accept() blocking problem.
118	* Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
119	* clients/servers which listen in on
120	* fixed ports.
121	* Alan Cox : Cleaned the above up and shrank it to
122	* a sensible code size.
123	* Alan Cox : Self connect lockup fix.
124	* Alan Cox : No connect to multicast.
125	* Ross Biro : Close unaccepted children on master
126	* socket close.
127	* Alan Cox : Reset tracing code.
128	* Alan Cox : Spurious resets on shutdown.
129	* Alan Cox : Giant 15 minute/60 second timer error
130	* Alan Cox : Small whoops in polling before an
131	* accept.
132	* Alan Cox : Kept the state trace facility since
133	* it's handy for debugging.
134	* Alan Cox : More reset handler fixes.
135	* Alan Cox : Started rewriting the code based on
136	* the RFC's for other useful protocol
137	* references see: Comer, KA9Q NOS, and
138	* for a reference on the difference
139	* between specifications and how BSD
140	* works see the 4.4lite source.
141	* A.N.Kuznetsov : Don't time wait on completion of tidy
142	* close.
143	* Linus Torvalds : Fin/Shutdown & copied_seq changes.
144	* Linus Torvalds : Fixed BSD port reuse to work first syn
145	* Alan Cox : Reimplemented timers as per the RFC
146	* and using multiple timers for sanity.
147	* Alan Cox : Small bug fixes, and a lot of new
148	* comments.
149	* Alan Cox : Fixed dual reader crash by locking
150	* the buffers (much like datagram.c)
151	* Alan Cox : Fixed stuck sockets in probe. A probe
152	* now gets fed up of retrying without
153	* (even a no space) answer.
154	* Alan Cox : Extracted closing code better
155	* Alan Cox : Fixed the closing state machine to
156	* resemble the RFC.
157	* Alan Cox : More 'per spec' fixes.
158	* Jorge Cwik : Even faster checksumming.
159	* Alan Cox : tcp_data() doesn't ack illegal PSH
160	* only frames. At least one pc tcp stack
161	* generates them.
162	* Alan Cox : Cache last socket.
163	* Alan Cox : Per route irtt.
164	* Matt Day : poll()->select() match BSD precisely on error
165	* Alan Cox : New buffers
166	* Marc Tamsky : Various sk->prot->retransmits and
167	* sk->retransmits misupdating fixed.
168	* Fixed tcp_write_timeout: stuck close,
169	* and TCP syn retries gets used now.
170	* Mark Yarvis : In tcp_read_wakeup(), don't send an
171	* ack if state is TCP_CLOSED.
172	* Alan Cox : Look up device on a retransmit - routes may
173	* change. Doesn't yet cope with MSS shrink right
174	* but it's a start!
175	* Marc Tamsky : Closing in closing fixes.
176	* Mike Shaver : RFC1122 verifications.
177	* Alan Cox : rcv_saddr errors.
178	* Alan Cox : Block double connect().
179	* Alan Cox : Small hooks for enSKIP.
180	* Alexey Kuznetsov: Path MTU discovery.
181	* Alan Cox : Support soft errors.
182	* Alan Cox : Fix MTU discovery pathological case
183	* when the remote claims no mtu!
184	* Marc Tamsky : TCP_CLOSE fix.
185	* Colin (G3TNE) : Send a reset on syn ack replies in
186	* window but wrong (fixes NT lpd problems)
187	* Pedro Roque : Better TCP window handling, delayed ack.
188	* Joerg Reuter : No modification of locked buffers in
189	* tcp_do_retransmit()
190	* Eric Schenk : Changed receiver side silly window
191	* avoidance algorithm to BSD style
192	* algorithm. This doubles throughput
193	* against machines running Solaris,
194	* and seems to result in general
195	* improvement.
196	* Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
197	* Willy Konynenberg : Transparent proxying support.
198	* Mike McLagan : Routing by source
199	* Keith Owens : Do proper merging with partial SKB's in
200	* tcp_do_sendmsg to avoid burstiness.
201	* Eric Schenk : Fix fast close down bug with
202	* shutdown() followed by close().
203	* Andi Kleen : Make poll agree with SIGIO
204	* Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
205	* lingertime == 0 (RFC 793 ABORT Call)
206	* Hirokazu Takahashi : Use copy_from_user() instead of
207	* csum_and_copy_from_user() if possible.
208	*
209	* Description of States:
210	*
211	* TCP_SYN_SENT sent a connection request, waiting for ack
212	*
213	* TCP_SYN_RECV received a connection request, sent ack,
214	* waiting for final ack in three-way handshake.
215	*
216	* TCP_ESTABLISHED connection established
217	*
218	* TCP_FIN_WAIT1 our side has shutdown, waiting to complete
219	* transmission of remaining buffered data
220	*
221	* TCP_FIN_WAIT2 all buffered data sent, waiting for remote
222	* to shutdown
223	*
224	* TCP_CLOSING both sides have shutdown but we still have
225	* data we have to finish sending
226	*
227	* TCP_TIME_WAIT timeout to catch resent junk before entering
228	* closed, can only be entered from FIN_WAIT2
229	* or CLOSING. Required because the other end
230	* may not have gotten our last ACK causing it
231	* to retransmit the data packet (which we ignore)
232	*
233	* TCP_CLOSE_WAIT remote side has shutdown and is waiting for
234	* us to finish writing our data and to shutdown
235	* (we have to close() to move on to LAST_ACK)
236	*
237	* TCP_LAST_ACK out side has shutdown after remote has
238	* shutdown. There may still be data in our
239	* buffer that we have to finish sending
240	*
241	* TCP_CLOSE socket is finished
242	*/
243
244	#define pr_fmt(fmt) "TCP: " fmt
245
246	#include <crypto/hash.h>
247	#include <linux/kernel.h>
248	#include <linux/module.h>
249	#include <linux/types.h>
250	#include <linux/fcntl.h>
251	#include <linux/poll.h>
252	#include <linux/inet_diag.h>
253	#include <linux/init.h>
254	#include <linux/fs.h>
255	#include <linux/skbuff.h>
256	#include <linux/scatterlist.h>
257	#include <linux/splice.h>
258	#include <linux/net.h>
259	#include <linux/socket.h>
260	#include <linux/random.h>
261	#include <linux/memblock.h>
262	#include <linux/highmem.h>
263	#include <linux/cache.h>
264	#include <linux/err.h>
265	#include <linux/time.h>
266	#include <linux/slab.h>
267	#include <linux/errqueue.h>
268	#include <linux/static_key.h>
269	#include <linux/btf.h>
270
271	#include <net/icmp.h>
272	#include <net/inet_common.h>
273	#include <net/tcp.h>
274	#include <net/mptcp.h>
275	#include <net/xfrm.h>
276	#include <net/ip.h>
277	#include <net/sock.h>
278
279	#include <linux/uaccess.h>
280	#include <asm/ioctls.h>
281	#include <net/busy_poll.h>
282	#include <net/rps.h>
283
284	/* Track pending CMSGs. */
285	enum {
286	TCP_CMSG_INQ = 1,
287	TCP_CMSG_TS = 2
288	};
289
290	DEFINE_PER_CPU(unsigned int, tcp_orphan_count);
291	EXPORT_PER_CPU_SYMBOL_GPL(tcp_orphan_count);
292
293	long sysctl_tcp_mem[3] __read_mostly;
294	EXPORT_SYMBOL(sysctl_tcp_mem);
295
296	atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp; /* Current allocated memory. */
297	EXPORT_SYMBOL(tcp_memory_allocated);
298	DEFINE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc);
299	EXPORT_PER_CPU_SYMBOL_GPL(tcp_memory_per_cpu_fw_alloc);
300
301	#if IS_ENABLED(CONFIG_SMC)
302	DEFINE_STATIC_KEY_FALSE(tcp_have_smc);
303	EXPORT_SYMBOL(tcp_have_smc);
304	#endif
305
306	/*
307	* Current number of TCP sockets.
308	*/
309	struct percpu_counter tcp_sockets_allocated ____cacheline_aligned_in_smp;
310	EXPORT_SYMBOL(tcp_sockets_allocated);
311
312	/*
313	* TCP splice context
314	*/
315	struct tcp_splice_state {
316	struct pipe_inode_info *pipe;
317	size_t len;
318	unsigned int flags;
319	};
320
321	/*
322	* Pressure flag: try to collapse.
323	* Technical note: it is used by multiple contexts non atomically.
324	* All the __sk_mem_schedule() is of this nature: accounting
325	* is strict, actions are advisory and have some latency.
326	*/
327	unsigned long tcp_memory_pressure __read_mostly;
328	EXPORT_SYMBOL_GPL(tcp_memory_pressure);
329
330	void tcp_enter_memory_pressure(struct sock *sk)
331	{
332	unsigned long val;
333
334	if (READ_ONCE(tcp_memory_pressure))
335	return;
336	val = jiffies;
337
338	if (!val)
339	val--;
340	if (!cmpxchg(&tcp_memory_pressure, 0, val))
341	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
342	}
343	EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure);
344
345	void tcp_leave_memory_pressure(struct sock *sk)
346	{
347	unsigned long val;
348
349	if (!READ_ONCE(tcp_memory_pressure))
350	return;
351	val = xchg(&tcp_memory_pressure, 0);
352	if (val)
353	NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO,
354	jiffies_to_msecs(jiffies - val));
355	}
356	EXPORT_SYMBOL_GPL(tcp_leave_memory_pressure);
357
358	/* Convert seconds to retransmits based on initial and max timeout */
359	static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
360	{
361	u8 res = 0;
362
363	if (seconds > 0) {
364	int period = timeout;
365
366	res = 1;
367	while (seconds > period && res < 255) {
368	res++;
369	timeout <<= 1;
370	if (timeout > rto_max)
371	timeout = rto_max;
372	period += timeout;
373	}
374	}
375	return res;
376	}
377
378	/* Convert retransmits to seconds based on initial and max timeout */
379	static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
380	{
381	int period = 0;
382
383	if (retrans > 0) {
384	period = timeout;
385	while (--retrans) {
386	timeout <<= 1;
387	if (timeout > rto_max)
388	timeout = rto_max;
389	period += timeout;
390	}
391	}
392	return period;
393	}
394
395	static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
396	{
397	u32 rate = READ_ONCE(tp->rate_delivered);
398	u32 intv = READ_ONCE(tp->rate_interval_us);
399	u64 rate64 = 0;
400
401	if (rate && intv) {
402	rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
403	do_div(rate64, intv);
404	}
405	return rate64;
406	}
407
408	/* Address-family independent initialization for a tcp_sock.
409	*
410	* NOTE: A lot of things set to zero explicitly by call to
411	* sk_alloc() so need not be done here.
412	*/
413	void tcp_init_sock(struct sock *sk)
414	{
415	struct inet_connection_sock *icsk = inet_csk(sk);
416	struct tcp_sock *tp = tcp_sk(sk);
417
418	tp->out_of_order_queue = RB_ROOT;
419	sk->tcp_rtx_queue = RB_ROOT;
420	tcp_init_xmit_timers(sk);
421	INIT_LIST_HEAD(list: &tp->tsq_node);
422	INIT_LIST_HEAD(list: &tp->tsorted_sent_queue);
423
424	icsk->icsk_rto = TCP_TIMEOUT_INIT;
425	icsk->icsk_rto_min = TCP_RTO_MIN;
426	icsk->icsk_delack_max = TCP_DELACK_MAX;
427	tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
428	minmax_reset(m: &tp->rtt_min, tcp_jiffies32, meas: ~0U);
429
430	/* So many TCP implementations out there (incorrectly) count the
431	* initial SYN frame in their delayed-ACK and congestion control
432	* algorithms that we must have the following bandaid to talk
433	* efficiently to them. -DaveM
434	*/
435	tcp_snd_cwnd_set(tp, TCP_INIT_CWND);
436
437	/* There's a bubble in the pipe until at least the first ACK. */
438	tp->app_limited = ~0U;
439	tp->rate_app_limited = 1;
440
441	/* See draft-stevens-tcpca-spec-01 for discussion of the
442	* initialization of these values.
443	*/
444	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
445	tp->snd_cwnd_clamp = ~0;
446	tp->mss_cache = TCP_MSS_DEFAULT;
447
448	tp->reordering = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering);
449	tcp_assign_congestion_control(sk);
450
451	tp->tsoffset = 0;
452	tp->rack.reo_wnd_steps = 1;
453
454	sk->sk_write_space = sk_stream_write_space;
455	sock_set_flag(sk, flag: SOCK_USE_WRITE_QUEUE);
456
457	icsk->icsk_sync_mss = tcp_sync_mss;
458
459	WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]));
460	WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]));
461	tcp_scaling_ratio_init(sk);
462
463	set_bit(SOCK_SUPPORT_ZC, addr: &sk->sk_socket->flags);
464	sk_sockets_allocated_inc(sk);
465	}
466	EXPORT_SYMBOL(tcp_init_sock);
467
468	static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
469	{
470	struct sk_buff *skb = tcp_write_queue_tail(sk);
471
472	if (tsflags && skb) {
473	struct skb_shared_info *shinfo = skb_shinfo(skb);
474	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
475
476	sock_tx_timestamp(sk, tsflags, tx_flags: &shinfo->tx_flags);
477	if (tsflags & SOF_TIMESTAMPING_TX_ACK)
478	tcb->txstamp_ack = 1;
479	if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
480	shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
481	}
482	}
483
484	static bool tcp_stream_is_readable(struct sock *sk, int target)
485	{
486	if (tcp_epollin_ready(sk, target))
487	return true;
488	return sk_is_readable(sk);
489	}
490
491	/*
492	* Wait for a TCP event.
493	*
494	* Note that we don't need to lock the socket, as the upper poll layers
495	* take care of normal races (between the test and the event) and we don't
496	* go look at any of the socket buffers directly.
497	*/
498	__poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
499	{
500	__poll_t mask;
501	struct sock *sk = sock->sk;
502	const struct tcp_sock *tp = tcp_sk(sk);
503	u8 shutdown;
504	int state;
505
506	sock_poll_wait(filp: file, sock, p: wait);
507
508	state = inet_sk_state_load(sk);
509	if (state == TCP_LISTEN)
510	return inet_csk_listen_poll(sk);
511
512	/* Socket is not locked. We are protected from async events
513	* by poll logic and correct handling of state changes
514	* made by other threads is impossible in any case.
515	*/
516
517	mask = 0;
518
519	/*
520	* EPOLLHUP is certainly not done right. But poll() doesn't
521	* have a notion of HUP in just one direction, and for a
522	* socket the read side is more interesting.
523	*
524	* Some poll() documentation says that EPOLLHUP is incompatible
525	* with the EPOLLOUT/POLLWR flags, so somebody should check this
526	* all. But careful, it tends to be safer to return too many
527	* bits than too few, and you can easily break real applications
528	* if you don't tell them that something has hung up!
529	*
530	* Check-me.
531	*
532	* Check number 1. EPOLLHUP is _UNMASKABLE_ event (see UNIX98 and
533	* our fs/select.c). It means that after we received EOF,
534	* poll always returns immediately, making impossible poll() on write()
535	* in state CLOSE_WAIT. One solution is evident --- to set EPOLLHUP
536	* if and only if shutdown has been made in both directions.
537	* Actually, it is interesting to look how Solaris and DUX
538	* solve this dilemma. I would prefer, if EPOLLHUP were maskable,
539	* then we could set it on SND_SHUTDOWN. BTW examples given
540	* in Stevens' books assume exactly this behaviour, it explains
541	* why EPOLLHUP is incompatible with EPOLLOUT. --ANK
542	*
543	* NOTE. Check for TCP_CLOSE is added. The goal is to prevent
544	* blocking on fresh not-connected or disconnected socket. --ANK
545	*/
546	shutdown = READ_ONCE(sk->sk_shutdown);
547	if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
548	mask |= EPOLLHUP;
549	if (shutdown & RCV_SHUTDOWN)
550	mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
551
552	/* Connected or passive Fast Open socket? */
553	if (state != TCP_SYN_SENT &&
554	(state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) {
555	int target = sock_rcvlowat(sk, waitall: 0, INT_MAX);
556	u16 urg_data = READ_ONCE(tp->urg_data);
557
558	if (unlikely(urg_data) &&
559	READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) &&
560	!sock_flag(sk, flag: SOCK_URGINLINE))
561	target++;
562
563	if (tcp_stream_is_readable(sk, target))
564	mask |= EPOLLIN | EPOLLRDNORM;
565
566	if (!(shutdown & SEND_SHUTDOWN)) {
567	if (__sk_stream_is_writeable(sk, wake: 1)) {
568	mask |= EPOLLOUT | EPOLLWRNORM;
569	} else { /* send SIGIO later */
570	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
571	set_bit(SOCK_NOSPACE, addr: &sk->sk_socket->flags);
572
573	/* Race breaker. If space is freed after
574	* wspace test but before the flags are set,
575	* IO signal will be lost. Memory barrier
576	* pairs with the input side.
577	*/
578	smp_mb__after_atomic();
579	if (__sk_stream_is_writeable(sk, wake: 1))
580	mask |= EPOLLOUT | EPOLLWRNORM;
581	}
582	} else
583	mask |= EPOLLOUT | EPOLLWRNORM;
584
585	if (urg_data & TCP_URG_VALID)
586	mask |= EPOLLPRI;
587	} else if (state == TCP_SYN_SENT &&
588	inet_test_bit(DEFER_CONNECT, sk)) {
589	/* Active TCP fastopen socket with defer_connect
590	* Return EPOLLOUT so application can call write()
591	* in order for kernel to generate SYN+data
592	*/
593	mask |= EPOLLOUT | EPOLLWRNORM;
594	}
595	/* This barrier is coupled with smp_wmb() in tcp_reset() */
596	smp_rmb();
597	if (READ_ONCE(sk->sk_err) ||
598	!skb_queue_empty_lockless(list: &sk->sk_error_queue))
599	mask |= EPOLLERR;
600
601	return mask;
602	}
603	EXPORT_SYMBOL(tcp_poll);
604
605	int tcp_ioctl(struct sock *sk, int cmd, int *karg)
606	{
607	struct tcp_sock *tp = tcp_sk(sk);
608	int answ;
609	bool slow;
610
611	switch (cmd) {
612	case SIOCINQ:
613	if (sk->sk_state == TCP_LISTEN)
614	return -EINVAL;
615
616	slow = lock_sock_fast(sk);
617	answ = tcp_inq(sk);
618	unlock_sock_fast(sk, slow);
619	break;
620	case SIOCATMARK:
621	answ = READ_ONCE(tp->urg_data) &&
622	READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq);
623	break;
624	case SIOCOUTQ:
625	if (sk->sk_state == TCP_LISTEN)
626	return -EINVAL;
627
628	if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
629	answ = 0;
630	else
631	answ = READ_ONCE(tp->write_seq) - tp->snd_una;
632	break;
633	case SIOCOUTQNSD:
634	if (sk->sk_state == TCP_LISTEN)
635	return -EINVAL;
636
637	if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
638	answ = 0;
639	else
640	answ = READ_ONCE(tp->write_seq) -
641	READ_ONCE(tp->snd_nxt);
642	break;
643	default:
644	return -ENOIOCTLCMD;
645	}
646
647	*karg = answ;
648	return 0;
649	}
650	EXPORT_SYMBOL(tcp_ioctl);
651
652	void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
653	{
654	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
655	tp->pushed_seq = tp->write_seq;
656	}
657
658	static inline bool forced_push(const struct tcp_sock *tp)
659	{
660	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
661	}
662
663	void tcp_skb_entail(struct sock *sk, struct sk_buff *skb)
664	{
665	struct tcp_sock *tp = tcp_sk(sk);
666	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
667
668	tcb->seq = tcb->end_seq = tp->write_seq;
669	tcb->tcp_flags = TCPHDR_ACK;
670	__skb_header_release(skb);
671	tcp_add_write_queue_tail(sk, skb);
672	sk_wmem_queued_add(sk, val: skb->truesize);
673	sk_mem_charge(sk, size: skb->truesize);
674	if (tp->nonagle & TCP_NAGLE_PUSH)
675	tp->nonagle &= ~TCP_NAGLE_PUSH;
676
677	tcp_slow_start_after_idle_check(sk);
678	}
679
680	static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
681	{
682	if (flags & MSG_OOB)
683	tp->snd_up = tp->write_seq;
684	}
685
686	/* If a not yet filled skb is pushed, do not send it if
687	* we have data packets in Qdisc or NIC queues :
688	* Because TX completion will happen shortly, it gives a chance
689	* to coalesce future sendmsg() payload into this skb, without
690	* need for a timer, and with no latency trade off.
691	* As packets containing data payload have a bigger truesize
692	* than pure acks (dataless) packets, the last checks prevent
693	* autocorking if we only have an ACK in Qdisc/NIC queues,
694	* or if TX completion was delayed after we processed ACK packet.
695	*/
696	static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
697	int size_goal)
698	{
699	return skb->len < size_goal &&
700	READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_autocorking) &&
701	!tcp_rtx_queue_empty(sk) &&
702	refcount_read(r: &sk->sk_wmem_alloc) > skb->truesize &&
703	tcp_skb_can_collapse_to(skb);
704	}
705
706	void tcp_push(struct sock *sk, int flags, int mss_now,
707	int nonagle, int size_goal)
708	{
709	struct tcp_sock *tp = tcp_sk(sk);
710	struct sk_buff *skb;
711
712	skb = tcp_write_queue_tail(sk);
713	if (!skb)
714	return;
715	if (!(flags & MSG_MORE) || forced_push(tp))
716	tcp_mark_push(tp, skb);
717
718	tcp_mark_urg(tp, flags);
719
720	if (tcp_should_autocork(sk, skb, size_goal)) {
721
722	/* avoid atomic op if TSQ_THROTTLED bit is already set */
723	if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {
724	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
725	set_bit(nr: TSQ_THROTTLED, addr: &sk->sk_tsq_flags);
726	smp_mb__after_atomic();
727	}
728	/* It is possible TX completion already happened
729	* before we set TSQ_THROTTLED.
730	*/
731	if (refcount_read(r: &sk->sk_wmem_alloc) > skb->truesize)
732	return;
733	}
734
735	if (flags & MSG_MORE)
736	nonagle = TCP_NAGLE_CORK;
737
738	__tcp_push_pending_frames(sk, cur_mss: mss_now, nonagle);
739	}
740
741	static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
742	unsigned int offset, size_t len)
743	{
744	struct tcp_splice_state *tss = rd_desc->arg.data;
745	int ret;
746
747	ret = skb_splice_bits(skb, sk: skb->sk, offset, pipe: tss->pipe,
748	min(rd_desc->count, len), flags: tss->flags);
749	if (ret > 0)
750	rd_desc->count -= ret;
751	return ret;
752	}
753
754	static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
755	{
756	/* Store TCP splice context information in read_descriptor_t. */
757	read_descriptor_t rd_desc = {
758	.arg.data = tss,
759	.count = tss->len,
760	};
761
762	return tcp_read_sock(sk, desc: &rd_desc, recv_actor: tcp_splice_data_recv);
763	}
764
765	/**
766	* tcp_splice_read - splice data from TCP socket to a pipe
767	* @sock: socket to splice from
768	* @ppos: position (not valid)
769	* @pipe: pipe to splice to
770	* @len: number of bytes to splice
771	* @flags: splice modifier flags
772	*
773	* Description:
774	* Will read pages from given socket and fill them into a pipe.
775	*
776	**/
777	ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
778	struct pipe_inode_info *pipe, size_t len,
779	unsigned int flags)
780	{
781	struct sock *sk = sock->sk;
782	struct tcp_splice_state tss = {
783	.pipe = pipe,
784	.len = len,
785	.flags = flags,
786	};
787	long timeo;
788	ssize_t spliced;
789	int ret;
790
791	sock_rps_record_flow(sk);
792	/*
793	* We can't seek on a socket input
794	*/
795	if (unlikely(*ppos))
796	return -ESPIPE;
797
798	ret = spliced = 0;
799
800	lock_sock(sk);
801
802	timeo = sock_rcvtimeo(sk, noblock: sock->file->f_flags & O_NONBLOCK);
803	while (tss.len) {
804	ret = __tcp_splice_read(sk, tss: &tss);
805	if (ret < 0)
806	break;
807	else if (!ret) {
808	if (spliced)
809	break;
810	if (sock_flag(sk, flag: SOCK_DONE))
811	break;
812	if (sk->sk_err) {
813	ret = sock_error(sk);
814	break;
815	}
816	if (sk->sk_shutdown & RCV_SHUTDOWN)
817	break;
818	if (sk->sk_state == TCP_CLOSE) {
819	/*
820	* This occurs when user tries to read
821	* from never connected socket.
822	*/
823	ret = -ENOTCONN;
824	break;
825	}
826	if (!timeo) {
827	ret = -EAGAIN;
828	break;
829	}
830	/* if __tcp_splice_read() got nothing while we have
831	* an skb in receive queue, we do not want to loop.
832	* This might happen with URG data.
833	*/
834	if (!skb_queue_empty(list: &sk->sk_receive_queue))
835	break;
836	ret = sk_wait_data(sk, timeo: &timeo, NULL);
837	if (ret < 0)
838	break;
839	if (signal_pending(current)) {
840	ret = sock_intr_errno(timeo);
841	break;
842	}
843	continue;
844	}
845	tss.len -= ret;
846	spliced += ret;
847
848	if (!tss.len || !timeo)
849	break;
850	release_sock(sk);
851	lock_sock(sk);
852
853	if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
854	(sk->sk_shutdown & RCV_SHUTDOWN) ||
855	signal_pending(current))
856	break;
857	}
858
859	release_sock(sk);
860
861	if (spliced)
862	return spliced;
863
864	return ret;
865	}
866	EXPORT_SYMBOL(tcp_splice_read);
867
868	struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp,
869	bool force_schedule)
870	{
871	struct sk_buff *skb;
872
873	skb = alloc_skb_fclone(MAX_TCP_HEADER, priority: gfp);
874	if (likely(skb)) {
875	bool mem_scheduled;
876
877	skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
878	if (force_schedule) {
879	mem_scheduled = true;
880	sk_forced_mem_schedule(sk, size: skb->truesize);
881	} else {
882	mem_scheduled = sk_wmem_schedule(sk, size: skb->truesize);
883	}
884	if (likely(mem_scheduled)) {
885	skb_reserve(skb, MAX_TCP_HEADER);
886	skb->ip_summed = CHECKSUM_PARTIAL;
887	INIT_LIST_HEAD(list: &skb->tcp_tsorted_anchor);
888	return skb;
889	}
890	__kfree_skb(skb);
891	} else {
892	sk->sk_prot->enter_memory_pressure(sk);
893	sk_stream_moderate_sndbuf(sk);
894	}
895	return NULL;
896	}
897
898	static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
899	int large_allowed)
900	{
901	struct tcp_sock *tp = tcp_sk(sk);
902	u32 new_size_goal, size_goal;
903
904	if (!large_allowed)
905	return mss_now;
906
907	/* Note : tcp_tso_autosize() will eventually split this later */
908	new_size_goal = tcp_bound_to_half_wnd(tp, pktsize: sk->sk_gso_max_size);
909
910	/* We try hard to avoid divides here */
911	size_goal = tp->gso_segs * mss_now;
912	if (unlikely(new_size_goal < size_goal ||
913	new_size_goal >= size_goal + mss_now)) {
914	tp->gso_segs = min_t(u16, new_size_goal / mss_now,
915	sk->sk_gso_max_segs);
916	size_goal = tp->gso_segs * mss_now;
917	}
918
919	return max(size_goal, mss_now);
920	}
921
922	int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
923	{
924	int mss_now;
925
926	mss_now = tcp_current_mss(sk);
927	*size_goal = tcp_xmit_size_goal(sk, mss_now, large_allowed: !(flags & MSG_OOB));
928
929	return mss_now;
930	}
931
932	/* In some cases, sendmsg() could have added an skb to the write queue,
933	* but failed adding payload on it. We need to remove it to consume less
934	* memory, but more importantly be able to generate EPOLLOUT for Edge Trigger
935	* epoll() users. Another reason is that tcp_write_xmit() does not like
936	* finding an empty skb in the write queue.
937	*/
938	void tcp_remove_empty_skb(struct sock *sk)
939	{
940	struct sk_buff *skb = tcp_write_queue_tail(sk);
941
942	if (skb && TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
943	tcp_unlink_write_queue(skb, sk);
944	if (tcp_write_queue_empty(sk))
945	tcp_chrono_stop(sk, type: TCP_CHRONO_BUSY);
946	tcp_wmem_free_skb(sk, skb);
947	}
948	}
949
950	/* skb changing from pure zc to mixed, must charge zc */
951	static int tcp_downgrade_zcopy_pure(struct sock *sk, struct sk_buff *skb)
952	{
953	if (unlikely(skb_zcopy_pure(skb))) {
954	u32 extra = skb->truesize -
955	SKB_TRUESIZE(skb_end_offset(skb));
956
957	if (!sk_wmem_schedule(sk, size: extra))
958	return -ENOMEM;
959
960	sk_mem_charge(sk, size: extra);
961	skb_shinfo(skb)->flags &= ~SKBFL_PURE_ZEROCOPY;
962	}
963	return 0;
964	}
965
966
967	int tcp_wmem_schedule(struct sock *sk, int copy)
968	{
969	int left;
970
971	if (likely(sk_wmem_schedule(sk, copy)))
972	return copy;
973
974	/* We could be in trouble if we have nothing queued.
975	* Use whatever is left in sk->sk_forward_alloc and tcp_wmem[0]
976	* to guarantee some progress.
977	*/
978	left = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]) - sk->sk_wmem_queued;
979	if (left > 0)
980	sk_forced_mem_schedule(sk, min(left, copy));
981	return min(copy, sk->sk_forward_alloc);
982	}
983
984	void tcp_free_fastopen_req(struct tcp_sock *tp)
985	{
986	if (tp->fastopen_req) {
987	kfree(objp: tp->fastopen_req);
988	tp->fastopen_req = NULL;
989	}
990	}
991
992	int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied,
993	size_t size, struct ubuf_info *uarg)
994	{
995	struct tcp_sock *tp = tcp_sk(sk);
996	struct inet_sock *inet = inet_sk(sk);
997	struct sockaddr *uaddr = msg->msg_name;
998	int err, flags;
999
1000	if (!(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) &
1001	TFO_CLIENT_ENABLE) ||
1002	(uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
1003	uaddr->sa_family == AF_UNSPEC))
1004	return -EOPNOTSUPP;
1005	if (tp->fastopen_req)
1006	return -EALREADY; /* Another Fast Open is in progress */
1007
1008	tp->fastopen_req = kzalloc(size: sizeof(struct tcp_fastopen_request),
1009	flags: sk->sk_allocation);
1010	if (unlikely(!tp->fastopen_req))
1011	return -ENOBUFS;
1012	tp->fastopen_req->data = msg;
1013	tp->fastopen_req->size = size;
1014	tp->fastopen_req->uarg = uarg;
1015
1016	if (inet_test_bit(DEFER_CONNECT, sk)) {
1017	err = tcp_connect(sk);
1018	/* Same failure procedure as in tcp_v4/6_connect */
1019	if (err) {
1020	tcp_set_state(sk, state: TCP_CLOSE);
1021	inet->inet_dport = 0;
1022	sk->sk_route_caps = 0;
1023	}
1024	}
1025	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1026	err = __inet_stream_connect(sock: sk->sk_socket, uaddr,
1027	addr_len: msg->msg_namelen, flags, is_sendmsg: 1);
1028	/* fastopen_req could already be freed in __inet_stream_connect
1029	* if the connection times out or gets rst
1030	*/
1031	if (tp->fastopen_req) {
1032	*copied = tp->fastopen_req->copied;
1033	tcp_free_fastopen_req(tp);
1034	inet_clear_bit(DEFER_CONNECT, sk);
1035	}
1036	return err;
1037	}
1038
1039	int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
1040	{
1041	struct tcp_sock *tp = tcp_sk(sk);
1042	struct ubuf_info *uarg = NULL;
1043	struct sk_buff *skb;
1044	struct sockcm_cookie sockc;
1045	int flags, err, copied = 0;
1046	int mss_now = 0, size_goal, copied_syn = 0;
1047	int process_backlog = 0;
1048	int zc = 0;
1049	long timeo;
1050
1051	flags = msg->msg_flags;
1052
1053	if ((flags & MSG_ZEROCOPY) && size) {
1054	if (msg->msg_ubuf) {
1055	uarg = msg->msg_ubuf;
1056	if (sk->sk_route_caps & NETIF_F_SG)
1057	zc = MSG_ZEROCOPY;
1058	} else if (sock_flag(sk, flag: SOCK_ZEROCOPY)) {
1059	skb = tcp_write_queue_tail(sk);
1060	uarg = msg_zerocopy_realloc(sk, size, uarg: skb_zcopy(skb));
1061	if (!uarg) {
1062	err = -ENOBUFS;
1063	goto out_err;
1064	}
1065	if (sk->sk_route_caps & NETIF_F_SG)
1066	zc = MSG_ZEROCOPY;
1067	else
1068	uarg_to_msgzc(uarg)->zerocopy = 0;
1069	}
1070	} else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
1071	if (sk->sk_route_caps & NETIF_F_SG)
1072	zc = MSG_SPLICE_PAGES;
1073	}
1074
1075	if (unlikely(flags & MSG_FASTOPEN ||
1076	inet_test_bit(DEFER_CONNECT, sk)) &&
1077	!tp->repair) {
1078	err = tcp_sendmsg_fastopen(sk, msg, copied: &copied_syn, size, uarg);
1079	if (err == -EINPROGRESS && copied_syn > 0)
1080	goto out;
1081	else if (err)
1082	goto out_err;
1083	}
1084
1085	timeo = sock_sndtimeo(sk, noblock: flags & MSG_DONTWAIT);
1086
1087	tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1088
1089	/* Wait for a connection to finish. One exception is TCP Fast Open
1090	* (passive side) where data is allowed to be sent before a connection
1091	* is fully established.
1092	*/
1093	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1094	!tcp_passive_fastopen(sk)) {
1095	err = sk_stream_wait_connect(sk, timeo_p: &timeo);
1096	if (err != 0)
1097	goto do_error;
1098	}
1099
1100	if (unlikely(tp->repair)) {
1101	if (tp->repair_queue == TCP_RECV_QUEUE) {
1102	copied = tcp_send_rcvq(sk, msg, size);
1103	goto out_nopush;
1104	}
1105
1106	err = -EINVAL;
1107	if (tp->repair_queue == TCP_NO_QUEUE)
1108	goto out_err;
1109
1110	/* 'common' sending to sendq */
1111	}
1112
1113	sockcm_init(sockc: &sockc, sk);
1114	if (msg->msg_controllen) {
1115	err = sock_cmsg_send(sk, msg, sockc: &sockc);
1116	if (unlikely(err)) {
1117	err = -EINVAL;
1118	goto out_err;
1119	}
1120	}
1121
1122	/* This should be in poll */
1123	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1124
1125	/* Ok commence sending. */
1126	copied = 0;
1127
1128	restart:
1129	mss_now = tcp_send_mss(sk, size_goal: &size_goal, flags);
1130
1131	err = -EPIPE;
1132	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1133	goto do_error;
1134
1135	while (msg_data_left(msg)) {
1136	ssize_t copy = 0;
1137
1138	skb = tcp_write_queue_tail(sk);
1139	if (skb)
1140	copy = size_goal - skb->len;
1141
1142	if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
1143	bool first_skb;
1144
1145	new_segment:
1146	if (!sk_stream_memory_free(sk))
1147	goto wait_for_space;
1148
1149	if (unlikely(process_backlog >= 16)) {
1150	process_backlog = 0;
1151	if (sk_flush_backlog(sk))
1152	goto restart;
1153	}
1154	first_skb = tcp_rtx_and_write_queues_empty(sk);
1155	skb = tcp_stream_alloc_skb(sk, gfp: sk->sk_allocation,
1156	force_schedule: first_skb);
1157	if (!skb)
1158	goto wait_for_space;
1159
1160	process_backlog++;
1161
1162	tcp_skb_entail(sk, skb);
1163	copy = size_goal;
1164
1165	/* All packets are restored as if they have
1166	* already been sent. skb_mstamp_ns isn't set to
1167	* avoid wrong rtt estimation.
1168	*/
1169	if (tp->repair)
1170	TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1171	}
1172
1173	/* Try to append data to the end of skb. */
1174	if (copy > msg_data_left(msg))
1175	copy = msg_data_left(msg);
1176
1177	if (zc == 0) {
1178	bool merge = true;
1179	int i = skb_shinfo(skb)->nr_frags;
1180	struct page_frag *pfrag = sk_page_frag(sk);
1181
1182	if (!sk_page_frag_refill(sk, pfrag))
1183	goto wait_for_space;
1184
1185	if (!skb_can_coalesce(skb, i, page: pfrag->page,
1186	off: pfrag->offset)) {
1187	if (i >= READ_ONCE(sysctl_max_skb_frags)) {
1188	tcp_mark_push(tp, skb);
1189	goto new_segment;
1190	}
1191	merge = false;
1192	}
1193
1194	copy = min_t(int, copy, pfrag->size - pfrag->offset);
1195
1196	if (unlikely(skb_zcopy_pure(skb) || skb_zcopy_managed(skb))) {
1197	if (tcp_downgrade_zcopy_pure(sk, skb))
1198	goto wait_for_space;
1199	skb_zcopy_downgrade_managed(skb);
1200	}
1201
1202	copy = tcp_wmem_schedule(sk, copy);
1203	if (!copy)
1204	goto wait_for_space;
1205
1206	err = skb_copy_to_page_nocache(sk, from: &msg->msg_iter, skb,
1207	page: pfrag->page,
1208	off: pfrag->offset,
1209	copy);
1210	if (err)
1211	goto do_error;
1212
1213	/* Update the skb. */
1214	if (merge) {
1215	skb_frag_size_add(frag: &skb_shinfo(skb)->frags[i - 1], delta: copy);
1216	} else {
1217	skb_fill_page_desc(skb, i, page: pfrag->page,
1218	off: pfrag->offset, size: copy);
1219	page_ref_inc(page: pfrag->page);
1220	}
1221	pfrag->offset += copy;
1222	} else if (zc == MSG_ZEROCOPY) {
1223	/* First append to a fragless skb builds initial
1224	* pure zerocopy skb
1225	*/
1226	if (!skb->len)
1227	skb_shinfo(skb)->flags |= SKBFL_PURE_ZEROCOPY;
1228
1229	if (!skb_zcopy_pure(skb)) {
1230	copy = tcp_wmem_schedule(sk, copy);
1231	if (!copy)
1232	goto wait_for_space;
1233	}
1234
1235	err = skb_zerocopy_iter_stream(sk, skb, msg, len: copy, uarg);
1236	if (err == -EMSGSIZE || err == -EEXIST) {
1237	tcp_mark_push(tp, skb);
1238	goto new_segment;
1239	}
1240	if (err < 0)
1241	goto do_error;
1242	copy = err;
1243	} else if (zc == MSG_SPLICE_PAGES) {
1244	/* Splice in data if we can; copy if we can't. */
1245	if (tcp_downgrade_zcopy_pure(sk, skb))
1246	goto wait_for_space;
1247	copy = tcp_wmem_schedule(sk, copy);
1248	if (!copy)
1249	goto wait_for_space;
1250
1251	err = skb_splice_from_iter(skb, iter: &msg->msg_iter, maxsize: copy,
1252	gfp: sk->sk_allocation);
1253	if (err < 0) {
1254	if (err == -EMSGSIZE) {
1255	tcp_mark_push(tp, skb);
1256	goto new_segment;
1257	}
1258	goto do_error;
1259	}
1260	copy = err;
1261
1262	if (!(flags & MSG_NO_SHARED_FRAGS))
1263	skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
1264
1265	sk_wmem_queued_add(sk, val: copy);
1266	sk_mem_charge(sk, size: copy);
1267	}
1268
1269	if (!copied)
1270	TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1271
1272	WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
1273	TCP_SKB_CB(skb)->end_seq += copy;
1274	tcp_skb_pcount_set(skb, segs: 0);
1275
1276	copied += copy;
1277	if (!msg_data_left(msg)) {
1278	if (unlikely(flags & MSG_EOR))
1279	TCP_SKB_CB(skb)->eor = 1;
1280	goto out;
1281	}
1282
1283	if (skb->len < size_goal || (flags & MSG_OOB) || unlikely(tp->repair))
1284	continue;
1285
1286	if (forced_push(tp)) {
1287	tcp_mark_push(tp, skb);
1288	__tcp_push_pending_frames(sk, cur_mss: mss_now, TCP_NAGLE_PUSH);
1289	} else if (skb == tcp_send_head(sk))
1290	tcp_push_one(sk, mss_now);
1291	continue;
1292
1293	wait_for_space:
1294	set_bit(SOCK_NOSPACE, addr: &sk->sk_socket->flags);
1295	tcp_remove_empty_skb(sk);
1296	if (copied)
1297	tcp_push(sk, flags: flags & ~MSG_MORE, mss_now,
1298	TCP_NAGLE_PUSH, size_goal);
1299
1300	err = sk_stream_wait_memory(sk, timeo_p: &timeo);
1301	if (err != 0)
1302	goto do_error;
1303
1304	mss_now = tcp_send_mss(sk, size_goal: &size_goal, flags);
1305	}
1306
1307	out:
1308	if (copied) {
1309	tcp_tx_timestamp(sk, tsflags: sockc.tsflags);
1310	tcp_push(sk, flags, mss_now, nonagle: tp->nonagle, size_goal);
1311	}
1312	out_nopush:
1313	/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
1314	if (uarg && !msg->msg_ubuf)
1315	net_zcopy_put(uarg);
1316	return copied + copied_syn;
1317
1318	do_error:
1319	tcp_remove_empty_skb(sk);
1320
1321	if (copied + copied_syn)
1322	goto out;
1323	out_err:
1324	/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
1325	if (uarg && !msg->msg_ubuf)
1326	net_zcopy_put_abort(uarg, have_uref: true);
1327	err = sk_stream_error(sk, flags, err);
1328	/* make sure we wake any epoll edge trigger waiter */
1329	if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {
1330	sk->sk_write_space(sk);
1331	tcp_chrono_stop(sk, type: TCP_CHRONO_SNDBUF_LIMITED);
1332	}
1333	return err;
1334	}
1335	EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
1336
1337	int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1338	{
1339	int ret;
1340
1341	lock_sock(sk);
1342	ret = tcp_sendmsg_locked(sk, msg, size);
1343	release_sock(sk);
1344
1345	return ret;
1346	}
1347	EXPORT_SYMBOL(tcp_sendmsg);
1348
1349	void tcp_splice_eof(struct socket *sock)
1350	{
1351	struct sock *sk = sock->sk;
1352	struct tcp_sock *tp = tcp_sk(sk);
1353	int mss_now, size_goal;
1354
1355	if (!tcp_write_queue_tail(sk))
1356	return;
1357
1358	lock_sock(sk);
1359	mss_now = tcp_send_mss(sk, size_goal: &size_goal, flags: 0);
1360	tcp_push(sk, flags: 0, mss_now, nonagle: tp->nonagle, size_goal);
1361	release_sock(sk);
1362	}
1363	EXPORT_SYMBOL_GPL(tcp_splice_eof);
1364
1365	/*
1366	* Handle reading urgent data. BSD has very simple semantics for
1367	* this, no blocking and very strange errors 8)
1368	*/
1369
1370	static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1371	{
1372	struct tcp_sock *tp = tcp_sk(sk);
1373
1374	/* No URG data to read. */
1375	if (sock_flag(sk, flag: SOCK_URGINLINE) || !tp->urg_data ||
1376	tp->urg_data == TCP_URG_READ)
1377	return -EINVAL; /* Yes this is right ! */
1378
1379	if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, flag: SOCK_DONE))
1380	return -ENOTCONN;
1381
1382	if (tp->urg_data & TCP_URG_VALID) {
1383	int err = 0;
1384	char c = tp->urg_data;
1385
1386	if (!(flags & MSG_PEEK))
1387	WRITE_ONCE(tp->urg_data, TCP_URG_READ);
1388
1389	/* Read urgent data. */
1390	msg->msg_flags |= MSG_OOB;
1391
1392	if (len > 0) {
1393	if (!(flags & MSG_TRUNC))
1394	err = memcpy_to_msg(msg, data: &c, len: 1);
1395	len = 1;
1396	} else
1397	msg->msg_flags |= MSG_TRUNC;
1398
1399	return err ? -EFAULT : len;
1400	}
1401
1402	if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1403	return 0;
1404
1405	/* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1406	* the available implementations agree in this case:
1407	* this call should never block, independent of the
1408	* blocking state of the socket.
1409	* Mike <pall@rz.uni-karlsruhe.de>
1410	*/
1411	return -EAGAIN;
1412	}
1413
1414	static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1415	{
1416	struct sk_buff *skb;
1417	int copied = 0, err = 0;
1418
1419	/* XXX -- need to support SO_PEEK_OFF */
1420
1421	skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
1422	err = skb_copy_datagram_msg(from: skb, offset: 0, msg, size: skb->len);
1423	if (err)
1424	return err;
1425	copied += skb->len;
1426	}
1427
1428	skb_queue_walk(&sk->sk_write_queue, skb) {
1429	err = skb_copy_datagram_msg(from: skb, offset: 0, msg, size: skb->len);
1430	if (err)
1431	break;
1432
1433	copied += skb->len;
1434	}
1435
1436	return err ?: copied;
1437	}
1438
1439	/* Clean up the receive buffer for full frames taken by the user,
1440	* then send an ACK if necessary. COPIED is the number of bytes
1441	* tcp_recvmsg has given to the user so far, it speeds up the
1442	* calculation of whether or not we must ACK for the sake of
1443	* a window update.
1444	*/
1445	void __tcp_cleanup_rbuf(struct sock *sk, int copied)
1446	{
1447	struct tcp_sock *tp = tcp_sk(sk);
1448	bool time_to_ack = false;
1449
1450	if (inet_csk_ack_scheduled(sk)) {
1451	const struct inet_connection_sock *icsk = inet_csk(sk);
1452
1453	if (/* Once-per-two-segments ACK was not sent by tcp_input.c */
1454	tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1455	/*
1456	* If this read emptied read buffer, we send ACK, if
1457	* connection is not bidirectional, user drained
1458	* receive buffer and there was a small segment
1459	* in queue.
1460	*/
1461	(copied > 0 &&
1462	((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1463	((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1464	!inet_csk_in_pingpong_mode(sk))) &&
1465	!atomic_read(v: &sk->sk_rmem_alloc)))
1466	time_to_ack = true;
1467	}
1468
1469	/* We send an ACK if we can now advertise a non-zero window
1470	* which has been raised "significantly".
1471	*
1472	* Even if window raised up to infinity, do not send window open ACK
1473	* in states, where we will not receive more. It is useless.
1474	*/
1475	if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1476	__u32 rcv_window_now = tcp_receive_window(tp);
1477
1478	/* Optimize, __tcp_select_window() is not cheap. */
1479	if (2*rcv_window_now <= tp->window_clamp) {
1480	__u32 new_window = __tcp_select_window(sk);
1481
1482	/* Send ACK now, if this read freed lots of space
1483	* in our buffer. Certainly, new_window is new window.
1484	* We can advertise it now, if it is not less than current one.
1485	* "Lots" means "at least twice" here.
1486	*/
1487	if (new_window && new_window >= 2 * rcv_window_now)
1488	time_to_ack = true;
1489	}
1490	}
1491	if (time_to_ack)
1492	tcp_send_ack(sk);
1493	}
1494
1495	void tcp_cleanup_rbuf(struct sock *sk, int copied)
1496	{
1497	struct sk_buff *skb = skb_peek(list_: &sk->sk_receive_queue);
1498	struct tcp_sock *tp = tcp_sk(sk);
1499
1500	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1501	"cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1502	tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1503	__tcp_cleanup_rbuf(sk, copied);
1504	}
1505
1506	static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb)
1507	{
1508	__skb_unlink(skb, list: &sk->sk_receive_queue);
1509	if (likely(skb->destructor == sock_rfree)) {
1510	sock_rfree(skb);
1511	skb->destructor = NULL;
1512	skb->sk = NULL;
1513	return skb_attempt_defer_free(skb);
1514	}
1515	__kfree_skb(skb);
1516	}
1517
1518	struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1519	{
1520	struct sk_buff *skb;
1521	u32 offset;
1522
1523	while ((skb = skb_peek(list_: &sk->sk_receive_queue)) != NULL) {
1524	offset = seq - TCP_SKB_CB(skb)->seq;
1525	if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1526	pr_err_once("%s: found a SYN, please report !\n", __func__);
1527	offset--;
1528	}
1529	if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1530	*off = offset;
1531	return skb;
1532	}
1533	/* This looks weird, but this can happen if TCP collapsing
1534	* splitted a fat GRO packet, while we released socket lock
1535	* in skb_splice_bits()
1536	*/
1537	tcp_eat_recv_skb(sk, skb);
1538	}
1539	return NULL;
1540	}
1541	EXPORT_SYMBOL(tcp_recv_skb);
1542
1543	/*
1544	* This routine provides an alternative to tcp_recvmsg() for routines
1545	* that would like to handle copying from skbuffs directly in 'sendfile'
1546	* fashion.
1547	* Note:
1548	* - It is assumed that the socket was locked by the caller.
1549	* - The routine does not block.
1550	* - At present, there is no support for reading OOB data
1551	* or for 'peeking' the socket using this routine
1552	* (although both would be easy to implement).
1553	*/
1554	int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1555	sk_read_actor_t recv_actor)
1556	{
1557	struct sk_buff *skb;
1558	struct tcp_sock *tp = tcp_sk(sk);
1559	u32 seq = tp->copied_seq;
1560	u32 offset;
1561	int copied = 0;
1562
1563	if (sk->sk_state == TCP_LISTEN)
1564	return -ENOTCONN;
1565	while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1566	if (offset < skb->len) {
1567	int used;
1568	size_t len;
1569
1570	len = skb->len - offset;
1571	/* Stop reading if we hit a patch of urgent data */
1572	if (unlikely(tp->urg_data)) {
1573	u32 urg_offset = tp->urg_seq - seq;
1574	if (urg_offset < len)
1575	len = urg_offset;
1576	if (!len)
1577	break;
1578	}
1579	used = recv_actor(desc, skb, offset, len);
1580	if (used <= 0) {
1581	if (!copied)
1582	copied = used;
1583	break;
1584	}
1585	if (WARN_ON_ONCE(used > len))
1586	used = len;
1587	seq += used;
1588	copied += used;
1589	offset += used;
1590
1591	/* If recv_actor drops the lock (e.g. TCP splice
1592	* receive) the skb pointer might be invalid when
1593	* getting here: tcp_collapse might have deleted it
1594	* while aggregating skbs from the socket queue.
1595	*/
1596	skb = tcp_recv_skb(sk, seq - 1, &offset);
1597	if (!skb)
1598	break;
1599	/* TCP coalescing might have appended data to the skb.
1600	* Try to splice more frags
1601	*/
1602	if (offset + 1 != skb->len)
1603	continue;
1604	}
1605	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1606	tcp_eat_recv_skb(sk, skb);
1607	++seq;
1608	break;
1609	}
1610	tcp_eat_recv_skb(sk, skb);
1611	if (!desc->count)
1612	break;
1613	WRITE_ONCE(tp->copied_seq, seq);
1614	}
1615	WRITE_ONCE(tp->copied_seq, seq);
1616
1617	tcp_rcv_space_adjust(sk);
1618
1619	/* Clean up data we have read: This will do ACK frames. */
1620	if (copied > 0) {
1621	tcp_recv_skb(sk, seq, &offset);
1622	tcp_cleanup_rbuf(sk, copied);
1623	}
1624	return copied;
1625	}
1626	EXPORT_SYMBOL(tcp_read_sock);
1627
1628	int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
1629	{
1630	struct sk_buff *skb;
1631	int copied = 0;
1632
1633	if (sk->sk_state == TCP_LISTEN)
1634	return -ENOTCONN;
1635
1636	while ((skb = skb_peek(list_: &sk->sk_receive_queue)) != NULL) {
1637	u8 tcp_flags;
1638	int used;
1639
1640	__skb_unlink(skb, list: &sk->sk_receive_queue);
1641	WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
1642	tcp_flags = TCP_SKB_CB(skb)->tcp_flags;
1643	used = recv_actor(sk, skb);
1644	if (used < 0) {
1645	if (!copied)
1646	copied = used;
1647	break;
1648	}
1649	copied += used;
1650
1651	if (tcp_flags & TCPHDR_FIN)
1652	break;
1653	}
1654	return copied;
1655	}
1656	EXPORT_SYMBOL(tcp_read_skb);
1657
1658	void tcp_read_done(struct sock *sk, size_t len)
1659	{
1660	struct tcp_sock *tp = tcp_sk(sk);
1661	u32 seq = tp->copied_seq;
1662	struct sk_buff *skb;
1663	size_t left;
1664	u32 offset;
1665
1666	if (sk->sk_state == TCP_LISTEN)
1667	return;
1668
1669	left = len;
1670	while (left && (skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1671	int used;
1672
1673	used = min_t(size_t, skb->len - offset, left);
1674	seq += used;
1675	left -= used;
1676
1677	if (skb->len > offset + used)
1678	break;
1679
1680	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1681	tcp_eat_recv_skb(sk, skb);
1682	++seq;
1683	break;
1684	}
1685	tcp_eat_recv_skb(sk, skb);
1686	}
1687	WRITE_ONCE(tp->copied_seq, seq);
1688
1689	tcp_rcv_space_adjust(sk);
1690
1691	/* Clean up data we have read: This will do ACK frames. */
1692	if (left != len)
1693	tcp_cleanup_rbuf(sk, copied: len - left);
1694	}
1695	EXPORT_SYMBOL(tcp_read_done);
1696
1697	int tcp_peek_len(struct socket *sock)
1698	{
1699	return tcp_inq(sk: sock->sk);
1700	}
1701	EXPORT_SYMBOL(tcp_peek_len);
1702
1703	/* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */
1704	int tcp_set_rcvlowat(struct sock *sk, int val)
1705	{
1706	int space, cap;
1707
1708	if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1709	cap = sk->sk_rcvbuf >> 1;
1710	else
1711	cap = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1;
1712	val = min(val, cap);
1713	WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
1714
1715	/* Check if we need to signal EPOLLIN right now */
1716	tcp_data_ready(sk);
1717
1718	if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1719	return 0;
1720
1721	space = tcp_space_from_win(sk, win: val);
1722	if (space > sk->sk_rcvbuf) {
1723	WRITE_ONCE(sk->sk_rcvbuf, space);
1724	tcp_sk(sk)->window_clamp = val;
1725	}
1726	return 0;
1727	}
1728	EXPORT_SYMBOL(tcp_set_rcvlowat);
1729
1730	void tcp_update_recv_tstamps(struct sk_buff *skb,
1731	struct scm_timestamping_internal *tss)
1732	{
1733	if (skb->tstamp)
1734	tss->ts[0] = ktime_to_timespec64(skb->tstamp);
1735	else
1736	tss->ts[0] = (struct timespec64) {0};
1737
1738	if (skb_hwtstamps(skb)->hwtstamp)
1739	tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp);
1740	else
1741	tss->ts[2] = (struct timespec64) {0};
1742	}
1743
1744	#ifdef CONFIG_MMU
1745	static const struct vm_operations_struct tcp_vm_ops = {
1746	};
1747
1748	int tcp_mmap(struct file *file, struct socket *sock,
1749	struct vm_area_struct *vma)
1750	{
1751	if (vma->vm_flags & (VM_WRITE | VM_EXEC))
1752	return -EPERM;
1753	vm_flags_clear(vma, VM_MAYWRITE | VM_MAYEXEC);
1754
1755	/* Instruct vm_insert_page() to not mmap_read_lock(mm) */
1756	vm_flags_set(vma, VM_MIXEDMAP);
1757
1758	vma->vm_ops = &tcp_vm_ops;
1759	return 0;
1760	}
1761	EXPORT_SYMBOL(tcp_mmap);
1762
1763	static skb_frag_t *skb_advance_to_frag(struct sk_buff *skb, u32 offset_skb,
1764	u32 *offset_frag)
1765	{
1766	skb_frag_t *frag;
1767
1768	if (unlikely(offset_skb >= skb->len))
1769	return NULL;
1770
1771	offset_skb -= skb_headlen(skb);
1772	if ((int)offset_skb < 0 || skb_has_frag_list(skb))
1773	return NULL;
1774
1775	frag = skb_shinfo(skb)->frags;
1776	while (offset_skb) {
1777	if (skb_frag_size(frag) > offset_skb) {
1778	*offset_frag = offset_skb;
1779	return frag;
1780	}
1781	offset_skb -= skb_frag_size(frag);
1782	++frag;
1783	}
1784	*offset_frag = 0;
1785	return frag;
1786	}
1787
1788	static bool can_map_frag(const skb_frag_t *frag)
1789	{
1790	struct page *page;
1791
1792	if (skb_frag_size(frag) != PAGE_SIZE || skb_frag_off(frag))
1793	return false;
1794
1795	page = skb_frag_page(frag);
1796
1797	if (PageCompound(page) || page->mapping)
1798	return false;
1799
1800	return true;
1801	}
1802
1803	static int find_next_mappable_frag(const skb_frag_t *frag,
1804	int remaining_in_skb)
1805	{
1806	int offset = 0;
1807
1808	if (likely(can_map_frag(frag)))
1809	return 0;
1810
1811	while (offset < remaining_in_skb && !can_map_frag(frag)) {
1812	offset += skb_frag_size(frag);
1813	++frag;
1814	}
1815	return offset;
1816	}
1817
1818	static void tcp_zerocopy_set_hint_for_skb(struct sock *sk,
1819	struct tcp_zerocopy_receive *zc,
1820	struct sk_buff *skb, u32 offset)
1821	{
1822	u32 frag_offset, partial_frag_remainder = 0;
1823	int mappable_offset;
1824	skb_frag_t *frag;
1825
1826	/* worst case: skip to next skb. try to improve on this case below */
1827	zc->recv_skip_hint = skb->len - offset;
1828
1829	/* Find the frag containing this offset (and how far into that frag) */
1830	frag = skb_advance_to_frag(skb, offset_skb: offset, offset_frag: &frag_offset);
1831	if (!frag)
1832	return;
1833
1834	if (frag_offset) {
1835	struct skb_shared_info *info = skb_shinfo(skb);
1836
1837	/* We read part of the last frag, must recvmsg() rest of skb. */
1838	if (frag == &info->frags[info->nr_frags - 1])
1839	return;
1840
1841	/* Else, we must at least read the remainder in this frag. */
1842	partial_frag_remainder = skb_frag_size(frag) - frag_offset;
1843	zc->recv_skip_hint -= partial_frag_remainder;
1844	++frag;
1845	}
1846
1847	/* partial_frag_remainder: If part way through a frag, must read rest.
1848	* mappable_offset: Bytes till next mappable frag, *not* counting bytes
1849	* in partial_frag_remainder.
1850	*/
1851	mappable_offset = find_next_mappable_frag(frag, remaining_in_skb: zc->recv_skip_hint);
1852	zc->recv_skip_hint = mappable_offset + partial_frag_remainder;
1853	}
1854
1855	static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
1856	int flags, struct scm_timestamping_internal *tss,
1857	int *cmsg_flags);
1858	static int receive_fallback_to_copy(struct sock *sk,
1859	struct tcp_zerocopy_receive *zc, int inq,
1860	struct scm_timestamping_internal *tss)
1861	{
1862	unsigned long copy_address = (unsigned long)zc->copybuf_address;
1863	struct msghdr msg = {};
1864	int err;
1865
1866	zc->length = 0;
1867	zc->recv_skip_hint = 0;
1868
1869	if (copy_address != zc->copybuf_address)
1870	return -EINVAL;
1871
1872	err = import_ubuf(ITER_DEST, buf: (void __user *)copy_address, len: inq,
1873	i: &msg.msg_iter);
1874	if (err)
1875	return err;
1876
1877	err = tcp_recvmsg_locked(sk, msg: &msg, len: inq, MSG_DONTWAIT,
1878	tss, cmsg_flags: &zc->msg_flags);
1879	if (err < 0)
1880	return err;
1881
1882	zc->copybuf_len = err;
1883	if (likely(zc->copybuf_len)) {
1884	struct sk_buff *skb;
1885	u32 offset;
1886
1887	skb = tcp_recv_skb(sk, tcp_sk(sk)->copied_seq, &offset);
1888	if (skb)
1889	tcp_zerocopy_set_hint_for_skb(sk, zc, skb, offset);
1890	}
1891	return 0;
1892	}
1893
1894	static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc,
1895	struct sk_buff *skb, u32 copylen,
1896	u32 *offset, u32 *seq)
1897	{
1898	unsigned long copy_address = (unsigned long)zc->copybuf_address;
1899	struct msghdr msg = {};
1900	int err;
1901
1902	if (copy_address != zc->copybuf_address)
1903	return -EINVAL;
1904
1905	err = import_ubuf(ITER_DEST, buf: (void __user *)copy_address, len: copylen,
1906	i: &msg.msg_iter);
1907	if (err)
1908	return err;
1909	err = skb_copy_datagram_msg(from: skb, offset: *offset, msg: &msg, size: copylen);
1910	if (err)
1911	return err;
1912	zc->recv_skip_hint -= copylen;
1913	*offset += copylen;
1914	*seq += copylen;
1915	return (__s32)copylen;
1916	}
1917
1918	static int tcp_zc_handle_leftover(struct tcp_zerocopy_receive *zc,
1919	struct sock *sk,
1920	struct sk_buff *skb,
1921	u32 *seq,
1922	s32 copybuf_len,
1923	struct scm_timestamping_internal *tss)
1924	{
1925	u32 offset, copylen = min_t(u32, copybuf_len, zc->recv_skip_hint);
1926
1927	if (!copylen)
1928	return 0;
1929	/* skb is null if inq < PAGE_SIZE. */
1930	if (skb) {
1931	offset = *seq - TCP_SKB_CB(skb)->seq;
1932	} else {
1933	skb = tcp_recv_skb(sk, *seq, &offset);
1934	if (TCP_SKB_CB(skb)->has_rxtstamp) {
1935	tcp_update_recv_tstamps(skb, tss);
1936	zc->msg_flags |= TCP_CMSG_TS;
1937	}
1938	}
1939
1940	zc->copybuf_len = tcp_copy_straggler_data(zc, skb, copylen, offset: &offset,
1941	seq);
1942	return zc->copybuf_len < 0 ? 0 : copylen;
1943	}
1944
1945	static int tcp_zerocopy_vm_insert_batch_error(struct vm_area_struct *vma,
1946	struct page **pending_pages,
1947	unsigned long pages_remaining,
1948	unsigned long *address,
1949	u32 *length,
1950	u32 *seq,
1951	struct tcp_zerocopy_receive *zc,
1952	u32 total_bytes_to_map,
1953	int err)
1954	{
1955	/* At least one page did not map. Try zapping if we skipped earlier. */
1956	if (err == -EBUSY &&
1957	zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT) {
1958	u32 maybe_zap_len;
1959
1960	maybe_zap_len = total_bytes_to_map - /* All bytes to map */
1961	*length + /* Mapped or pending */
1962	(pages_remaining * PAGE_SIZE); /* Failed map. */
1963	zap_page_range_single(vma, address: *address, size: maybe_zap_len, NULL);
1964	err = 0;
1965	}
1966
1967	if (!err) {
1968	unsigned long leftover_pages = pages_remaining;
1969	int bytes_mapped;
1970
1971	/* We called zap_page_range_single, try to reinsert. */
1972	err = vm_insert_pages(vma, addr: *address,
1973	pages: pending_pages,
1974	num: &pages_remaining);
1975	bytes_mapped = PAGE_SIZE * (leftover_pages - pages_remaining);
1976	*seq += bytes_mapped;
1977	*address += bytes_mapped;
1978	}
1979	if (err) {
1980	/* Either we were unable to zap, OR we zapped, retried an
1981	* insert, and still had an issue. Either ways, pages_remaining
1982	* is the number of pages we were unable to map, and we unroll
1983	* some state we speculatively touched before.
1984	*/
1985	const int bytes_not_mapped = PAGE_SIZE * pages_remaining;
1986
1987	*length -= bytes_not_mapped;
1988	zc->recv_skip_hint += bytes_not_mapped;
1989	}
1990	return err;
1991	}
1992
1993	static int tcp_zerocopy_vm_insert_batch(struct vm_area_struct *vma,
1994	struct page **pages,
1995	unsigned int pages_to_map,
1996	unsigned long *address,
1997	u32 *length,
1998	u32 *seq,
1999	struct tcp_zerocopy_receive *zc,
2000	u32 total_bytes_to_map)
2001	{
2002	unsigned long pages_remaining = pages_to_map;
2003	unsigned int pages_mapped;
2004	unsigned int bytes_mapped;
2005	int err;
2006
2007	err = vm_insert_pages(vma, addr: *address, pages, num: &pages_remaining);
2008	pages_mapped = pages_to_map - (unsigned int)pages_remaining;
2009	bytes_mapped = PAGE_SIZE * pages_mapped;
2010	/* Even if vm_insert_pages fails, it may have partially succeeded in
2011	* mapping (some but not all of the pages).
2012	*/
2013	*seq += bytes_mapped;
2014	*address += bytes_mapped;
2015
2016	if (likely(!err))
2017	return 0;
2018
2019	/* Error: maybe zap and retry + rollback state for failed inserts. */
2020	return tcp_zerocopy_vm_insert_batch_error(vma, pending_pages: pages + pages_mapped,
2021	pages_remaining, address, length, seq, zc, total_bytes_to_map,
2022	err);
2023	}
2024
2025	#define TCP_VALID_ZC_MSG_FLAGS (TCP_CMSG_TS)
2026	static void tcp_zc_finalize_rx_tstamp(struct sock *sk,
2027	struct tcp_zerocopy_receive *zc,
2028	struct scm_timestamping_internal *tss)
2029	{
2030	unsigned long msg_control_addr;
2031	struct msghdr cmsg_dummy;
2032
2033	msg_control_addr = (unsigned long)zc->msg_control;
2034	cmsg_dummy.msg_control_user = (void __user *)msg_control_addr;
2035	cmsg_dummy.msg_controllen =
2036	(__kernel_size_t)zc->msg_controllen;
2037	cmsg_dummy.msg_flags = in_compat_syscall()
2038	? MSG_CMSG_COMPAT : 0;
2039	cmsg_dummy.msg_control_is_user = true;
2040	zc->msg_flags = 0;
2041	if (zc->msg_control == msg_control_addr &&
2042	zc->msg_controllen == cmsg_dummy.msg_controllen) {
2043	tcp_recv_timestamp(msg: &cmsg_dummy, sk, tss);
2044	zc->msg_control = (__u64)
2045	((uintptr_t)cmsg_dummy.msg_control_user);
2046	zc->msg_controllen =
2047	(__u64)cmsg_dummy.msg_controllen;
2048	zc->msg_flags = (__u32)cmsg_dummy.msg_flags;
2049	}
2050	}
2051
2052	static struct vm_area_struct *find_tcp_vma(struct mm_struct *mm,
2053	unsigned long address,
2054	bool *mmap_locked)
2055	{
2056	struct vm_area_struct *vma = lock_vma_under_rcu(mm, address);
2057
2058	if (vma) {
2059	if (vma->vm_ops != &tcp_vm_ops) {
2060	vma_end_read(vma);
2061	return NULL;
2062	}
2063	*mmap_locked = false;
2064	return vma;
2065	}
2066
2067	mmap_read_lock(mm);
2068	vma = vma_lookup(mm, addr: address);
2069	if (!vma || vma->vm_ops != &tcp_vm_ops) {
2070	mmap_read_unlock(mm);
2071	return NULL;
2072	}
2073	*mmap_locked = true;
2074	return vma;
2075	}
2076
2077	#define TCP_ZEROCOPY_PAGE_BATCH_SIZE 32
2078	static int tcp_zerocopy_receive(struct sock *sk,
2079	struct tcp_zerocopy_receive *zc,
2080	struct scm_timestamping_internal *tss)
2081	{
2082	u32 length = 0, offset, vma_len, avail_len, copylen = 0;
2083	unsigned long address = (unsigned long)zc->address;
2084	struct page *pages[TCP_ZEROCOPY_PAGE_BATCH_SIZE];
2085	s32 copybuf_len = zc->copybuf_len;
2086	struct tcp_sock *tp = tcp_sk(sk);
2087	const skb_frag_t *frags = NULL;
2088	unsigned int pages_to_map = 0;
2089	struct vm_area_struct *vma;
2090	struct sk_buff *skb = NULL;
2091	u32 seq = tp->copied_seq;
2092	u32 total_bytes_to_map;
2093	int inq = tcp_inq(sk);
2094	bool mmap_locked;
2095	int ret;
2096
2097	zc->copybuf_len = 0;
2098	zc->msg_flags = 0;
2099
2100	if (address & (PAGE_SIZE - 1) || address != zc->address)
2101	return -EINVAL;
2102
2103	if (sk->sk_state == TCP_LISTEN)
2104	return -ENOTCONN;
2105
2106	sock_rps_record_flow(sk);
2107
2108	if (inq && inq <= copybuf_len)
2109	return receive_fallback_to_copy(sk, zc, inq, tss);
2110
2111	if (inq < PAGE_SIZE) {
2112	zc->length = 0;
2113	zc->recv_skip_hint = inq;
2114	if (!inq && sock_flag(sk, flag: SOCK_DONE))
2115	return -EIO;
2116	return 0;
2117	}
2118
2119	vma = find_tcp_vma(current->mm, address, mmap_locked: &mmap_locked);
2120	if (!vma)
2121	return -EINVAL;
2122
2123	vma_len = min_t(unsigned long, zc->length, vma->vm_end - address);
2124	avail_len = min_t(u32, vma_len, inq);
2125	total_bytes_to_map = avail_len & ~(PAGE_SIZE - 1);
2126	if (total_bytes_to_map) {
2127	if (!(zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT))
2128	zap_page_range_single(vma, address, size: total_bytes_to_map,
2129	NULL);
2130	zc->length = total_bytes_to_map;
2131	zc->recv_skip_hint = 0;
2132	} else {
2133	zc->length = avail_len;
2134	zc->recv_skip_hint = avail_len;
2135	}
2136	ret = 0;
2137	while (length + PAGE_SIZE <= zc->length) {
2138	int mappable_offset;
2139	struct page *page;
2140
2141	if (zc->recv_skip_hint < PAGE_SIZE) {
2142	u32 offset_frag;
2143
2144	if (skb) {
2145	if (zc->recv_skip_hint > 0)
2146	break;
2147	skb = skb->next;
2148	offset = seq - TCP_SKB_CB(skb)->seq;
2149	} else {
2150	skb = tcp_recv_skb(sk, seq, &offset);
2151	}
2152
2153	if (TCP_SKB_CB(skb)->has_rxtstamp) {
2154	tcp_update_recv_tstamps(skb, tss);
2155	zc->msg_flags |= TCP_CMSG_TS;
2156	}
2157	zc->recv_skip_hint = skb->len - offset;
2158	frags = skb_advance_to_frag(skb, offset_skb: offset, offset_frag: &offset_frag);
2159	if (!frags || offset_frag)
2160	break;
2161	}
2162
2163	mappable_offset = find_next_mappable_frag(frag: frags,
2164	remaining_in_skb: zc->recv_skip_hint);
2165	if (mappable_offset) {
2166	zc->recv_skip_hint = mappable_offset;
2167	break;
2168	}
2169	page = skb_frag_page(frag: frags);
2170	prefetchw(x: page);
2171	pages[pages_to_map++] = page;
2172	length += PAGE_SIZE;
2173	zc->recv_skip_hint -= PAGE_SIZE;
2174	frags++;
2175	if (pages_to_map == TCP_ZEROCOPY_PAGE_BATCH_SIZE ||
2176	zc->recv_skip_hint < PAGE_SIZE) {
2177	/* Either full batch, or we're about to go to next skb
2178	* (and we cannot unroll failed ops across skbs).
2179	*/
2180	ret = tcp_zerocopy_vm_insert_batch(vma, pages,
2181	pages_to_map,
2182	address: &address, length: &length,
2183	seq: &seq, zc,
2184	total_bytes_to_map);
2185	if (ret)
2186	goto out;
2187	pages_to_map = 0;
2188	}
2189	}
2190	if (pages_to_map) {
2191	ret = tcp_zerocopy_vm_insert_batch(vma, pages, pages_to_map,
2192	address: &address, length: &length, seq: &seq,
2193	zc, total_bytes_to_map);
2194	}
2195	out:
2196	if (mmap_locked)
2197	mmap_read_unlock(current->mm);
2198	else
2199	vma_end_read(vma);
2200	/* Try to copy straggler data. */
2201	if (!ret)
2202	copylen = tcp_zc_handle_leftover(zc, sk, skb, seq: &seq, copybuf_len, tss);
2203
2204	if (length + copylen) {
2205	WRITE_ONCE(tp->copied_seq, seq);
2206	tcp_rcv_space_adjust(sk);
2207
2208	/* Clean up data we have read: This will do ACK frames. */
2209	tcp_recv_skb(sk, seq, &offset);
2210	tcp_cleanup_rbuf(sk, copied: length + copylen);
2211	ret = 0;
2212	if (length == zc->length)
2213	zc->recv_skip_hint = 0;
2214	} else {
2215	if (!zc->recv_skip_hint && sock_flag(sk, flag: SOCK_DONE))
2216	ret = -EIO;
2217	}
2218	zc->length = length;
2219	return ret;
2220	}
2221	#endif
2222
2223	/* Similar to __sock_recv_timestamp, but does not require an skb */
2224	void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
2225	struct scm_timestamping_internal *tss)
2226	{
2227	int new_tstamp = sock_flag(sk, flag: SOCK_TSTAMP_NEW);
2228	bool has_timestamping = false;
2229
2230	if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
2231	if (sock_flag(sk, flag: SOCK_RCVTSTAMP)) {
2232	if (sock_flag(sk, flag: SOCK_RCVTSTAMPNS)) {
2233	if (new_tstamp) {
2234	struct __kernel_timespec kts = {
2235	.tv_sec = tss->ts[0].tv_sec,
2236	.tv_nsec = tss->ts[0].tv_nsec,
2237	};
2238	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
2239	len: sizeof(kts), data: &kts);
2240	} else {
2241	struct __kernel_old_timespec ts_old = {
2242	.tv_sec = tss->ts[0].tv_sec,
2243	.tv_nsec = tss->ts[0].tv_nsec,
2244	};
2245	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
2246	len: sizeof(ts_old), data: &ts_old);
2247	}
2248	} else {
2249	if (new_tstamp) {
2250	struct __kernel_sock_timeval stv = {
2251	.tv_sec = tss->ts[0].tv_sec,
2252	.tv_usec = tss->ts[0].tv_nsec / 1000,
2253	};
2254	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_NEW,
2255	len: sizeof(stv), data: &stv);
2256	} else {
2257	struct __kernel_old_timeval tv = {
2258	.tv_sec = tss->ts[0].tv_sec,
2259	.tv_usec = tss->ts[0].tv_nsec / 1000,
2260	};
2261	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD,
2262	len: sizeof(tv), data: &tv);
2263	}
2264	}
2265	}
2266
2267	if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_SOFTWARE)
2268	has_timestamping = true;
2269	else
2270	tss->ts[0] = (struct timespec64) {0};
2271	}
2272
2273	if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
2274	if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_RAW_HARDWARE)
2275	has_timestamping = true;
2276	else
2277	tss->ts[2] = (struct timespec64) {0};
2278	}
2279
2280	if (has_timestamping) {
2281	tss->ts[1] = (struct timespec64) {0};
2282	if (sock_flag(sk, SOCK_TSTAMP_NEW))
2283	put_cmsg_scm_timestamping64(msg, tss);
2284	else
2285	put_cmsg_scm_timestamping(msg, tss);
2286	}
2287	}
2288
2289	static int tcp_inq_hint(struct sock *sk)
2290	{
2291	const struct tcp_sock *tp = tcp_sk(sk);
2292	u32 copied_seq = READ_ONCE(tp->copied_seq);
2293	u32 rcv_nxt = READ_ONCE(tp->rcv_nxt);
2294	int inq;
2295
2296	inq = rcv_nxt - copied_seq;
2297	if (unlikely(inq < 0 || copied_seq != READ_ONCE(tp->copied_seq))) {
2298	lock_sock(sk);
2299	inq = tp->rcv_nxt - tp->copied_seq;
2300	release_sock(sk);
2301	}
2302	/* After receiving a FIN, tell the user-space to continue reading
2303	* by returning a non-zero inq.
2304	*/
2305	if (inq == 0 && sock_flag(sk, flag: SOCK_DONE))
2306	inq = 1;
2307	return inq;
2308	}
2309
2310	/*
2311	* This routine copies from a sock struct into the user buffer.
2312	*
2313	* Technical note: in 2.3 we work on _locked_ socket, so that
2314	* tricks with *seq access order and skb->users are not required.
2315	* Probably, code can be easily improved even more.
2316	*/
2317
2318	static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
2319	int flags, struct scm_timestamping_internal *tss,
2320	int *cmsg_flags)
2321	{
2322	struct tcp_sock *tp = tcp_sk(sk);
2323	int copied = 0;
2324	u32 peek_seq;
2325	u32 *seq;
2326	unsigned long used;
2327	int err;
2328	int target; /* Read at least this many bytes */
2329	long timeo;
2330	struct sk_buff *skb, *last;
2331	u32 urg_hole = 0;
2332
2333	err = -ENOTCONN;
2334	if (sk->sk_state == TCP_LISTEN)
2335	goto out;
2336
2337	if (tp->recvmsg_inq) {
2338	*cmsg_flags = TCP_CMSG_INQ;
2339	msg->msg_get_inq = 1;
2340	}
2341	timeo = sock_rcvtimeo(sk, noblock: flags & MSG_DONTWAIT);
2342
2343	/* Urgent data needs to be handled specially. */
2344	if (flags & MSG_OOB)
2345	goto recv_urg;
2346
2347	if (unlikely(tp->repair)) {
2348	err = -EPERM;
2349	if (!(flags & MSG_PEEK))
2350	goto out;
2351
2352	if (tp->repair_queue == TCP_SEND_QUEUE)
2353	goto recv_sndq;
2354
2355	err = -EINVAL;
2356	if (tp->repair_queue == TCP_NO_QUEUE)
2357	goto out;
2358
2359	/* 'common' recv queue MSG_PEEK-ing */
2360	}
2361
2362	seq = &tp->copied_seq;
2363	if (flags & MSG_PEEK) {
2364	peek_seq = tp->copied_seq;
2365	seq = &peek_seq;
2366	}
2367
2368	target = sock_rcvlowat(sk, waitall: flags & MSG_WAITALL, len);
2369
2370	do {
2371	u32 offset;
2372
2373	/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
2374	if (unlikely(tp->urg_data) && tp->urg_seq == *seq) {
2375	if (copied)
2376	break;
2377	if (signal_pending(current)) {
2378	copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
2379	break;
2380	}
2381	}
2382
2383	/* Next get a buffer. */
2384
2385	last = skb_peek_tail(list_: &sk->sk_receive_queue);
2386	skb_queue_walk(&sk->sk_receive_queue, skb) {
2387	last = skb;
2388	/* Now that we have two receive queues this
2389	* shouldn't happen.
2390	*/
2391	if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
2392	"TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
2393	*seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
2394	flags))
2395	break;
2396
2397	offset = *seq - TCP_SKB_CB(skb)->seq;
2398	if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
2399	pr_err_once("%s: found a SYN, please report !\n", __func__);
2400	offset--;
2401	}
2402	if (offset < skb->len)
2403	goto found_ok_skb;
2404	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2405	goto found_fin_ok;
2406	WARN(!(flags & MSG_PEEK),
2407	"TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
2408	*seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
2409	}
2410
2411	/* Well, if we have backlog, try to process it now yet. */
2412
2413	if (copied >= target && !READ_ONCE(sk->sk_backlog.tail))
2414	break;
2415
2416	if (copied) {
2417	if (!timeo ||
2418	sk->sk_err ||
2419	sk->sk_state == TCP_CLOSE ||
2420	(sk->sk_shutdown & RCV_SHUTDOWN) ||
2421	signal_pending(current))
2422	break;
2423	} else {
2424	if (sock_flag(sk, flag: SOCK_DONE))
2425	break;
2426
2427	if (sk->sk_err) {
2428	copied = sock_error(sk);
2429	break;
2430	}
2431
2432	if (sk->sk_shutdown & RCV_SHUTDOWN)
2433	break;
2434
2435	if (sk->sk_state == TCP_CLOSE) {
2436	/* This occurs when user tries to read
2437	* from never connected socket.
2438	*/
2439	copied = -ENOTCONN;
2440	break;
2441	}
2442
2443	if (!timeo) {
2444	copied = -EAGAIN;
2445	break;
2446	}
2447
2448	if (signal_pending(current)) {
2449	copied = sock_intr_errno(timeo);
2450	break;
2451	}
2452	}
2453
2454	if (copied >= target) {
2455	/* Do not sleep, just process backlog. */
2456	__sk_flush_backlog(sk);
2457	} else {
2458	tcp_cleanup_rbuf(sk, copied);
2459	err = sk_wait_data(sk, timeo: &timeo, skb: last);
2460	if (err < 0) {
2461	err = copied ? : err;
2462	goto out;
2463	}
2464	}
2465
2466	if ((flags & MSG_PEEK) &&
2467	(peek_seq - copied - urg_hole != tp->copied_seq)) {
2468	net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
2469	current->comm,
2470	task_pid_nr(current));
2471	peek_seq = tp->copied_seq;
2472	}
2473	continue;
2474
2475	found_ok_skb:
2476	/* Ok so how much can we use? */
2477	used = skb->len - offset;
2478	if (len < used)
2479	used = len;
2480
2481	/* Do we have urgent data here? */
2482	if (unlikely(tp->urg_data)) {
2483	u32 urg_offset = tp->urg_seq - *seq;
2484	if (urg_offset < used) {
2485	if (!urg_offset) {
2486	if (!sock_flag(sk, flag: SOCK_URGINLINE)) {
2487	WRITE_ONCE(*seq, *seq + 1);
2488	urg_hole++;
2489	offset++;
2490	used--;
2491	if (!used)
2492	goto skip_copy;
2493	}
2494	} else
2495	used = urg_offset;
2496	}
2497	}
2498
2499	if (!(flags & MSG_TRUNC)) {
2500	err = skb_copy_datagram_msg(from: skb, offset, msg, size: used);
2501	if (err) {
2502	/* Exception. Bailout! */
2503	if (!copied)
2504	copied = -EFAULT;
2505	break;
2506	}
2507	}
2508
2509	WRITE_ONCE(*seq, *seq + used);
2510	copied += used;
2511	len -= used;
2512
2513	tcp_rcv_space_adjust(sk);
2514
2515	skip_copy:
2516	if (unlikely(tp->urg_data) && after(tp->copied_seq, tp->urg_seq)) {
2517	WRITE_ONCE(tp->urg_data, 0);
2518	tcp_fast_path_check(sk);
2519	}
2520
2521	if (TCP_SKB_CB(skb)->has_rxtstamp) {
2522	tcp_update_recv_tstamps(skb, tss);
2523	*cmsg_flags |= TCP_CMSG_TS;
2524	}
2525
2526	if (used + offset < skb->len)
2527	continue;
2528
2529	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2530	goto found_fin_ok;
2531	if (!(flags & MSG_PEEK))
2532	tcp_eat_recv_skb(sk, skb);
2533	continue;
2534
2535	found_fin_ok:
2536	/* Process the FIN. */
2537	WRITE_ONCE(*seq, *seq + 1);
2538	if (!(flags & MSG_PEEK))
2539	tcp_eat_recv_skb(sk, skb);
2540	break;
2541	} while (len > 0);
2542
2543	/* According to UNIX98, msg_name/msg_namelen are ignored
2544	* on connected socket. I was just happy when found this 8) --ANK
2545	*/
2546
2547	/* Clean up data we have read: This will do ACK frames. */
2548	tcp_cleanup_rbuf(sk, copied);
2549	return copied;
2550
2551	out:
2552	return err;
2553
2554	recv_urg:
2555	err = tcp_recv_urg(sk, msg, len, flags);
2556	goto out;
2557
2558	recv_sndq:
2559	err = tcp_peek_sndq(sk, msg, len);
2560	goto out;
2561	}
2562
2563	int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
2564	int *addr_len)
2565	{
2566	int cmsg_flags = 0, ret;
2567	struct scm_timestamping_internal tss;
2568
2569	if (unlikely(flags & MSG_ERRQUEUE))
2570	return inet_recv_error(sk, msg, len, addr_len);
2571
2572	if (sk_can_busy_loop(sk) &&
2573	skb_queue_empty_lockless(list: &sk->sk_receive_queue) &&
2574	sk->sk_state == TCP_ESTABLISHED)
2575	sk_busy_loop(sk, nonblock: flags & MSG_DONTWAIT);
2576
2577	lock_sock(sk);
2578	ret = tcp_recvmsg_locked(sk, msg, len, flags, tss: &tss, cmsg_flags: &cmsg_flags);
2579	release_sock(sk);
2580
2581	if ((cmsg_flags || msg->msg_get_inq) && ret >= 0) {
2582	if (cmsg_flags & TCP_CMSG_TS)
2583	tcp_recv_timestamp(msg, sk, tss: &tss);
2584	if (msg->msg_get_inq) {
2585	msg->msg_inq = tcp_inq_hint(sk);
2586	if (cmsg_flags & TCP_CMSG_INQ)
2587	put_cmsg(msg, SOL_TCP, TCP_CM_INQ,
2588	len: sizeof(msg->msg_inq), data: &msg->msg_inq);
2589	}
2590	}
2591	return ret;
2592	}
2593	EXPORT_SYMBOL(tcp_recvmsg);
2594
2595	void tcp_set_state(struct sock *sk, int state)
2596	{
2597	int oldstate = sk->sk_state;
2598
2599	/* We defined a new enum for TCP states that are exported in BPF
2600	* so as not force the internal TCP states to be frozen. The
2601	* following checks will detect if an internal state value ever
2602	* differs from the BPF value. If this ever happens, then we will
2603	* need to remap the internal value to the BPF value before calling
2604	* tcp_call_bpf_2arg.
2605	*/
2606	BUILD_BUG_ON((int)BPF_TCP_ESTABLISHED != (int)TCP_ESTABLISHED);
2607	BUILD_BUG_ON((int)BPF_TCP_SYN_SENT != (int)TCP_SYN_SENT);
2608	BUILD_BUG_ON((int)BPF_TCP_SYN_RECV != (int)TCP_SYN_RECV);
2609	BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT1 != (int)TCP_FIN_WAIT1);
2610	BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT2 != (int)TCP_FIN_WAIT2);
2611	BUILD_BUG_ON((int)BPF_TCP_TIME_WAIT != (int)TCP_TIME_WAIT);
2612	BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE);
2613	BUILD_BUG_ON((int)BPF_TCP_CLOSE_WAIT != (int)TCP_CLOSE_WAIT);
2614	BUILD_BUG_ON((int)BPF_TCP_LAST_ACK != (int)TCP_LAST_ACK);
2615	BUILD_BUG_ON((int)BPF_TCP_LISTEN != (int)TCP_LISTEN);
2616	BUILD_BUG_ON((int)BPF_TCP_CLOSING != (int)TCP_CLOSING);
2617	BUILD_BUG_ON((int)BPF_TCP_NEW_SYN_RECV != (int)TCP_NEW_SYN_RECV);
2618	BUILD_BUG_ON((int)BPF_TCP_BOUND_INACTIVE != (int)TCP_BOUND_INACTIVE);
2619	BUILD_BUG_ON((int)BPF_TCP_MAX_STATES != (int)TCP_MAX_STATES);
2620
2621	/* bpf uapi header bpf.h defines an anonymous enum with values
2622	* BPF_TCP_* used by bpf programs. Currently gcc built vmlinux
2623	* is able to emit this enum in DWARF due to the above BUILD_BUG_ON.
2624	* But clang built vmlinux does not have this enum in DWARF
2625	* since clang removes the above code before generating IR/debuginfo.
2626	* Let us explicitly emit the type debuginfo to ensure the
2627	* above-mentioned anonymous enum in the vmlinux DWARF and hence BTF
2628	* regardless of which compiler is used.
2629	*/
2630	BTF_TYPE_EMIT_ENUM(BPF_TCP_ESTABLISHED);
2631
2632	if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_STATE_CB_FLAG))
2633	tcp_call_bpf_2arg(sk, op: BPF_SOCK_OPS_STATE_CB, arg1: oldstate, arg2: state);
2634
2635	switch (state) {
2636	case TCP_ESTABLISHED:
2637	if (oldstate != TCP_ESTABLISHED)
2638	TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2639	break;
2640
2641	case TCP_CLOSE:
2642	if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
2643	TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
2644
2645	sk->sk_prot->unhash(sk);
2646	if (inet_csk(sk)->icsk_bind_hash &&
2647	!(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2648	inet_put_port(sk);
2649	fallthrough;
2650	default:
2651	if (oldstate == TCP_ESTABLISHED)
2652	TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2653	}
2654
2655	/* Change state AFTER socket is unhashed to avoid closed
2656	* socket sitting in hash tables.
2657	*/
2658	inet_sk_state_store(sk, newstate: state);
2659	}
2660	EXPORT_SYMBOL_GPL(tcp_set_state);
2661
2662	/*
2663	* State processing on a close. This implements the state shift for
2664	* sending our FIN frame. Note that we only send a FIN for some
2665	* states. A shutdown() may have already sent the FIN, or we may be
2666	* closed.
2667	*/
2668
2669	static const unsigned char new_state[16] = {
2670	/* current state: new state: action: */
2671	[0 /* (Invalid) */] = TCP_CLOSE,
2672	[TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2673	[TCP_SYN_SENT] = TCP_CLOSE,
2674	[TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2675	[TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2676	[TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2677	[TCP_TIME_WAIT] = TCP_CLOSE,
2678	[TCP_CLOSE] = TCP_CLOSE,
2679	[TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2680	[TCP_LAST_ACK] = TCP_LAST_ACK,
2681	[TCP_LISTEN] = TCP_CLOSE,
2682	[TCP_CLOSING] = TCP_CLOSING,
2683	[TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2684	};
2685
2686	static int tcp_close_state(struct sock *sk)
2687	{
2688	int next = (int)new_state[sk->sk_state];
2689	int ns = next & TCP_STATE_MASK;
2690
2691	tcp_set_state(sk, ns);
2692
2693	return next & TCP_ACTION_FIN;
2694	}
2695
2696	/*
2697	* Shutdown the sending side of a connection. Much like close except
2698	* that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2699	*/
2700
2701	void tcp_shutdown(struct sock *sk, int how)
2702	{
2703	/* We need to grab some memory, and put together a FIN,
2704	* and then put it into the queue to be sent.
2705	* Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2706	*/
2707	if (!(how & SEND_SHUTDOWN))
2708	return;
2709
2710	/* If we've already sent a FIN, or it's a closed state, skip this. */
2711	if ((1 << sk->sk_state) &
2712	(TCPF_ESTABLISHED | TCPF_SYN_SENT |
2713	TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2714	/* Clear out any half completed packets. FIN if needed. */
2715	if (tcp_close_state(sk))
2716	tcp_send_fin(sk);
2717	}
2718	}
2719	EXPORT_SYMBOL(tcp_shutdown);
2720
2721	int tcp_orphan_count_sum(void)
2722	{
2723	int i, total = 0;
2724
2725	for_each_possible_cpu(i)
2726	total += per_cpu(tcp_orphan_count, i);
2727
2728	return max(total, 0);
2729	}
2730
2731	static int tcp_orphan_cache;
2732	static struct timer_list tcp_orphan_timer;
2733	#define TCP_ORPHAN_TIMER_PERIOD msecs_to_jiffies(100)
2734
2735	static void tcp_orphan_update(struct timer_list *unused)
2736	{
2737	WRITE_ONCE(tcp_orphan_cache, tcp_orphan_count_sum());
2738	mod_timer(timer: &tcp_orphan_timer, expires: jiffies + TCP_ORPHAN_TIMER_PERIOD);
2739	}
2740
2741	static bool tcp_too_many_orphans(int shift)
2742	{
2743	return READ_ONCE(tcp_orphan_cache) << shift >
2744	READ_ONCE(sysctl_tcp_max_orphans);
2745	}
2746
2747	bool tcp_check_oom(struct sock *sk, int shift)
2748	{
2749	bool too_many_orphans, out_of_socket_memory;
2750
2751	too_many_orphans = tcp_too_many_orphans(shift);
2752	out_of_socket_memory = tcp_out_of_memory(sk);
2753
2754	if (too_many_orphans)
2755	net_info_ratelimited("too many orphaned sockets\n");
2756	if (out_of_socket_memory)
2757	net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2758	return too_many_orphans || out_of_socket_memory;
2759	}
2760
2761	void __tcp_close(struct sock *sk, long timeout)
2762	{
2763	struct sk_buff *skb;
2764	int data_was_unread = 0;
2765	int state;
2766
2767	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2768
2769	if (sk->sk_state == TCP_LISTEN) {
2770	tcp_set_state(sk, TCP_CLOSE);
2771
2772	/* Special case. */
2773	inet_csk_listen_stop(sk);
2774
2775	goto adjudge_to_death;
2776	}
2777
2778	/* We need to flush the recv. buffs. We do this only on the
2779	* descriptor close, not protocol-sourced closes, because the
2780	* reader process may not have drained the data yet!
2781	*/
2782	while ((skb = __skb_dequeue(list: &sk->sk_receive_queue)) != NULL) {
2783	u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2784
2785	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2786	len--;
2787	data_was_unread += len;
2788	__kfree_skb(skb);
2789	}
2790
2791	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2792	if (sk->sk_state == TCP_CLOSE)
2793	goto adjudge_to_death;
2794
2795	/* As outlined in RFC 2525, section 2.17, we send a RST here because
2796	* data was lost. To witness the awful effects of the old behavior of
2797	* always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2798	* GET in an FTP client, suspend the process, wait for the client to
2799	* advertise a zero window, then kill -9 the FTP client, wheee...
2800	* Note: timeout is always zero in such a case.
2801	*/
2802	if (unlikely(tcp_sk(sk)->repair)) {
2803	sk->sk_prot->disconnect(sk, 0);
2804	} else if (data_was_unread) {
2805	/* Unread data was tossed, zap the connection. */
2806	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2807	tcp_set_state(sk, TCP_CLOSE);
2808	tcp_send_active_reset(sk, priority: sk->sk_allocation);
2809	} else if (sock_flag(sk, flag: SOCK_LINGER) && !sk->sk_lingertime) {
2810	/* Check zero linger _after_ checking for unread data. */
2811	sk->sk_prot->disconnect(sk, 0);
2812	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2813	} else if (tcp_close_state(sk)) {
2814	/* We FIN if the application ate all the data before
2815	* zapping the connection.
2816	*/
2817
2818	/* RED-PEN. Formally speaking, we have broken TCP state
2819	* machine. State transitions:
2820	*
2821	* TCP_ESTABLISHED -> TCP_FIN_WAIT1
2822	* TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2823	* TCP_CLOSE_WAIT -> TCP_LAST_ACK
2824	*
2825	* are legal only when FIN has been sent (i.e. in window),
2826	* rather than queued out of window. Purists blame.
2827	*
2828	* F.e. "RFC state" is ESTABLISHED,
2829	* if Linux state is FIN-WAIT-1, but FIN is still not sent.
2830	*
2831	* The visible declinations are that sometimes
2832	* we enter time-wait state, when it is not required really
2833	* (harmless), do not send active resets, when they are
2834	* required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2835	* they look as CLOSING or LAST_ACK for Linux)
2836	* Probably, I missed some more holelets.
2837	* --ANK
2838	* XXX (TFO) - To start off we don't support SYN+ACK+FIN
2839	* in a single packet! (May consider it later but will
2840	* probably need API support or TCP_CORK SYN-ACK until
2841	* data is written and socket is closed.)
2842	*/
2843	tcp_send_fin(sk);
2844	}
2845
2846	sk_stream_wait_close(sk, timeo_p: timeout);
2847
2848	adjudge_to_death:
2849	state = sk->sk_state;
2850	sock_hold(sk);
2851	sock_orphan(sk);
2852
2853	local_bh_disable();
2854	bh_lock_sock(sk);
2855	/* remove backlog if any, without releasing ownership. */
2856	__release_sock(sk);
2857
2858	this_cpu_inc(tcp_orphan_count);
2859
2860	/* Have we already been destroyed by a softirq or backlog? */
2861	if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2862	goto out;
2863
2864	/* This is a (useful) BSD violating of the RFC. There is a
2865	* problem with TCP as specified in that the other end could
2866	* keep a socket open forever with no application left this end.
2867	* We use a 1 minute timeout (about the same as BSD) then kill
2868	* our end. If they send after that then tough - BUT: long enough
2869	* that we won't make the old 4*rto = almost no time - whoops
2870	* reset mistake.
2871	*
2872	* Nope, it was not mistake. It is really desired behaviour
2873	* f.e. on http servers, when such sockets are useless, but
2874	* consume significant resources. Let's do it with special
2875	* linger2 option. --ANK
2876	*/
2877
2878	if (sk->sk_state == TCP_FIN_WAIT2) {
2879	struct tcp_sock *tp = tcp_sk(sk);
2880	if (READ_ONCE(tp->linger2) < 0) {
2881	tcp_set_state(sk, TCP_CLOSE);
2882	tcp_send_active_reset(sk, GFP_ATOMIC);
2883	__NET_INC_STATS(sock_net(sk),
2884	LINUX_MIB_TCPABORTONLINGER);
2885	} else {
2886	const int tmo = tcp_fin_time(sk);
2887
2888	if (tmo > TCP_TIMEWAIT_LEN) {
2889	inet_csk_reset_keepalive_timer(sk,
2890	timeout: tmo - TCP_TIMEWAIT_LEN);
2891	} else {
2892	tcp_time_wait(sk, state: TCP_FIN_WAIT2, timeo: tmo);
2893	goto out;
2894	}
2895	}
2896	}
2897	if (sk->sk_state != TCP_CLOSE) {
2898	if (tcp_check_oom(sk, shift: 0)) {
2899	tcp_set_state(sk, TCP_CLOSE);
2900	tcp_send_active_reset(sk, GFP_ATOMIC);
2901	__NET_INC_STATS(sock_net(sk),
2902	LINUX_MIB_TCPABORTONMEMORY);
2903	} else if (!check_net(net: sock_net(sk))) {
2904	/* Not possible to send reset; just close */
2905	tcp_set_state(sk, TCP_CLOSE);
2906	}
2907	}
2908
2909	if (sk->sk_state == TCP_CLOSE) {
2910	struct request_sock *req;
2911
2912	req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk,
2913	lockdep_sock_is_held(sk));
2914	/* We could get here with a non-NULL req if the socket is
2915	* aborted (e.g., closed with unread data) before 3WHS
2916	* finishes.
2917	*/
2918	if (req)
2919	reqsk_fastopen_remove(sk, req, reset: false);
2920	inet_csk_destroy_sock(sk);
2921	}
2922	/* Otherwise, socket is reprieved until protocol close. */
2923
2924	out:
2925	bh_unlock_sock(sk);
2926	local_bh_enable();
2927	}
2928
2929	void tcp_close(struct sock *sk, long timeout)
2930	{
2931	lock_sock(sk);
2932	__tcp_close(sk, timeout);
2933	release_sock(sk);
2934	if (!sk->sk_net_refcnt)
2935	inet_csk_clear_xmit_timers_sync(sk);
2936	sock_put(sk);
2937	}
2938	EXPORT_SYMBOL(tcp_close);
2939
2940	/* These states need RST on ABORT according to RFC793 */
2941
2942	static inline bool tcp_need_reset(int state)
2943	{
2944	return (1 << state) &
2945	(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2946	TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2947	}
2948
2949	static void tcp_rtx_queue_purge(struct sock *sk)
2950	{
2951	struct rb_node *p = rb_first(&sk->tcp_rtx_queue);
2952
2953	tcp_sk(sk)->highest_sack = NULL;
2954	while (p) {
2955	struct sk_buff *skb = rb_to_skb(p);
2956
2957	p = rb_next(p);
2958	/* Since we are deleting whole queue, no need to
2959	* list_del(&skb->tcp_tsorted_anchor)
2960	*/
2961	tcp_rtx_queue_unlink(skb, sk);
2962	tcp_wmem_free_skb(sk, skb);
2963	}
2964	}
2965
2966	void tcp_write_queue_purge(struct sock *sk)
2967	{
2968	struct sk_buff *skb;
2969
2970	tcp_chrono_stop(sk, type: TCP_CHRONO_BUSY);
2971	while ((skb = __skb_dequeue(list: &sk->sk_write_queue)) != NULL) {
2972	tcp_skb_tsorted_anchor_cleanup(skb);
2973	tcp_wmem_free_skb(sk, skb);
2974	}
2975	tcp_rtx_queue_purge(sk);
2976	INIT_LIST_HEAD(list: &tcp_sk(sk)->tsorted_sent_queue);
2977	tcp_clear_all_retrans_hints(tcp_sk(sk));
2978	tcp_sk(sk)->packets_out = 0;
2979	inet_csk(sk)->icsk_backoff = 0;
2980	}
2981
2982	int tcp_disconnect(struct sock *sk, int flags)
2983	{
2984	struct inet_sock *inet = inet_sk(sk);
2985	struct inet_connection_sock *icsk = inet_csk(sk);
2986	struct tcp_sock *tp = tcp_sk(sk);
2987	int old_state = sk->sk_state;
2988	u32 seq;
2989
2990	if (old_state != TCP_CLOSE)
2991	tcp_set_state(sk, TCP_CLOSE);
2992
2993	/* ABORT function of RFC793 */
2994	if (old_state == TCP_LISTEN) {
2995	inet_csk_listen_stop(sk);
2996	} else if (unlikely(tp->repair)) {
2997	WRITE_ONCE(sk->sk_err, ECONNABORTED);
2998	} else if (tcp_need_reset(state: old_state) ||
2999	(tp->snd_nxt != tp->write_seq &&
3000	(1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
3001	/* The last check adjusts for discrepancy of Linux wrt. RFC
3002	* states
3003	*/
3004	tcp_send_active_reset(sk, priority: gfp_any());
3005	WRITE_ONCE(sk->sk_err, ECONNRESET);
3006	} else if (old_state == TCP_SYN_SENT)
3007	WRITE_ONCE(sk->sk_err, ECONNRESET);
3008
3009	tcp_clear_xmit_timers(sk);
3010	__skb_queue_purge(list: &sk->sk_receive_queue);
3011	WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
3012	WRITE_ONCE(tp->urg_data, 0);
3013	tcp_write_queue_purge(sk);
3014	tcp_fastopen_active_disable_ofo_check(sk);
3015	skb_rbtree_purge(root: &tp->out_of_order_queue);
3016
3017	inet->inet_dport = 0;
3018
3019	inet_bhash2_reset_saddr(sk);
3020
3021	WRITE_ONCE(sk->sk_shutdown, 0);
3022	sock_reset_flag(sk, flag: SOCK_DONE);
3023	tp->srtt_us = 0;
3024	tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
3025	tp->rcv_rtt_last_tsecr = 0;
3026
3027	seq = tp->write_seq + tp->max_window + 2;
3028	if (!seq)
3029	seq = 1;
3030	WRITE_ONCE(tp->write_seq, seq);
3031
3032	icsk->icsk_backoff = 0;
3033	icsk->icsk_probes_out = 0;
3034	icsk->icsk_probes_tstamp = 0;
3035	icsk->icsk_rto = TCP_TIMEOUT_INIT;
3036	icsk->icsk_rto_min = TCP_RTO_MIN;
3037	icsk->icsk_delack_max = TCP_DELACK_MAX;
3038	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
3039	tcp_snd_cwnd_set(tp, TCP_INIT_CWND);
3040	tp->snd_cwnd_cnt = 0;
3041	tp->is_cwnd_limited = 0;
3042	tp->max_packets_out = 0;
3043	tp->window_clamp = 0;
3044	tp->delivered = 0;
3045	tp->delivered_ce = 0;
3046	if (icsk->icsk_ca_ops->release)
3047	icsk->icsk_ca_ops->release(sk);
3048	memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
3049	icsk->icsk_ca_initialized = 0;
3050	tcp_set_ca_state(sk, ca_state: TCP_CA_Open);
3051	tp->is_sack_reneg = 0;
3052	tcp_clear_retrans(tp);
3053	tp->total_retrans = 0;
3054	inet_csk_delack_init(sk);
3055	/* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
3056	* issue in __tcp_select_window()
3057	*/
3058	icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
3059	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
3060	__sk_dst_reset(sk);
3061	dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL));
3062	tcp_saved_syn_free(tp);
3063	tp->compressed_ack = 0;
3064	tp->segs_in = 0;
3065	tp->segs_out = 0;
3066	tp->bytes_sent = 0;
3067	tp->bytes_acked = 0;
3068	tp->bytes_received = 0;
3069	tp->bytes_retrans = 0;
3070	tp->data_segs_in = 0;
3071	tp->data_segs_out = 0;
3072	tp->duplicate_sack[0].start_seq = 0;
3073	tp->duplicate_sack[0].end_seq = 0;
3074	tp->dsack_dups = 0;
3075	tp->reord_seen = 0;
3076	tp->retrans_out = 0;
3077	tp->sacked_out = 0;
3078	tp->tlp_high_seq = 0;
3079	tp->last_oow_ack_time = 0;
3080	tp->plb_rehash = 0;
3081	/* There's a bubble in the pipe until at least the first ACK. */
3082	tp->app_limited = ~0U;
3083	tp->rate_app_limited = 1;
3084	tp->rack.mstamp = 0;
3085	tp->rack.advanced = 0;
3086	tp->rack.reo_wnd_steps = 1;
3087	tp->rack.last_delivered = 0;
3088	tp->rack.reo_wnd_persist = 0;
3089	tp->rack.dsack_seen = 0;
3090	tp->syn_data_acked = 0;
3091	tp->rx_opt.saw_tstamp = 0;
3092	tp->rx_opt.dsack = 0;
3093	tp->rx_opt.num_sacks = 0;
3094	tp->rcv_ooopack = 0;
3095
3096
3097	/* Clean up fastopen related fields */
3098	tcp_free_fastopen_req(tp);
3099	inet_clear_bit(DEFER_CONNECT, sk);
3100	tp->fastopen_client_fail = 0;
3101
3102	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
3103
3104	if (sk->sk_frag.page) {
3105	put_page(page: sk->sk_frag.page);
3106	sk->sk_frag.page = NULL;
3107	sk->sk_frag.offset = 0;
3108	}
3109	sk_error_report(sk);
3110	return 0;
3111	}
3112	EXPORT_SYMBOL(tcp_disconnect);
3113
3114	static inline bool tcp_can_repair_sock(const struct sock *sk)
3115	{
3116	return sockopt_ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
3117	(sk->sk_state != TCP_LISTEN);
3118	}
3119
3120	static int tcp_repair_set_window(struct tcp_sock *tp, sockptr_t optbuf, int len)
3121	{
3122	struct tcp_repair_window opt;
3123
3124	if (!tp->repair)
3125	return -EPERM;
3126
3127	if (len != sizeof(opt))
3128	return -EINVAL;
3129
3130	if (copy_from_sockptr(dst: &opt, src: optbuf, size: sizeof(opt)))
3131	return -EFAULT;
3132
3133	if (opt.max_window < opt.snd_wnd)
3134	return -EINVAL;
3135
3136	if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
3137	return -EINVAL;
3138
3139	if (after(opt.rcv_wup, tp->rcv_nxt))
3140	return -EINVAL;
3141
3142	tp->snd_wl1 = opt.snd_wl1;
3143	tp->snd_wnd = opt.snd_wnd;
3144	tp->max_window = opt.max_window;
3145
3146	tp->rcv_wnd = opt.rcv_wnd;
3147	tp->rcv_wup = opt.rcv_wup;
3148
3149	return 0;
3150	}
3151
3152	static int tcp_repair_options_est(struct sock *sk, sockptr_t optbuf,
3153	unsigned int len)
3154	{
3155	struct tcp_sock *tp = tcp_sk(sk);
3156	struct tcp_repair_opt opt;
3157	size_t offset = 0;
3158
3159	while (len >= sizeof(opt)) {
3160	if (copy_from_sockptr_offset(dst: &opt, src: optbuf, offset, size: sizeof(opt)))
3161	return -EFAULT;
3162
3163	offset += sizeof(opt);
3164	len -= sizeof(opt);
3165
3166	switch (opt.opt_code) {
3167	case TCPOPT_MSS:
3168	tp->rx_opt.mss_clamp = opt.opt_val;
3169	tcp_mtup_init(sk);
3170	break;
3171	case TCPOPT_WINDOW:
3172	{
3173	u16 snd_wscale = opt.opt_val & 0xFFFF;
3174	u16 rcv_wscale = opt.opt_val >> 16;
3175
3176	if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
3177	return -EFBIG;
3178
3179	tp->rx_opt.snd_wscale = snd_wscale;
3180	tp->rx_opt.rcv_wscale = rcv_wscale;
3181	tp->rx_opt.wscale_ok = 1;
3182	}
3183	break;
3184	case TCPOPT_SACK_PERM:
3185	if (opt.opt_val != 0)
3186	return -EINVAL;
3187
3188	tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
3189	break;
3190	case TCPOPT_TIMESTAMP:
3191	if (opt.opt_val != 0)
3192	return -EINVAL;
3193
3194	tp->rx_opt.tstamp_ok = 1;
3195	break;
3196	}
3197	}
3198
3199	return 0;
3200	}
3201
3202	DEFINE_STATIC_KEY_FALSE(tcp_tx_delay_enabled);
3203	EXPORT_SYMBOL(tcp_tx_delay_enabled);
3204
3205	static void tcp_enable_tx_delay(void)
3206	{
3207	if (!static_branch_unlikely(&tcp_tx_delay_enabled)) {
3208	static int __tcp_tx_delay_enabled = 0;
3209
3210	if (cmpxchg(&__tcp_tx_delay_enabled, 0, 1) == 0) {
3211	static_branch_enable(&tcp_tx_delay_enabled);
3212	pr_info("TCP_TX_DELAY enabled\n");
3213	}
3214	}
3215	}
3216
3217	/* When set indicates to always queue non-full frames. Later the user clears
3218	* this option and we transmit any pending partial frames in the queue. This is
3219	* meant to be used alongside sendfile() to get properly filled frames when the
3220	* user (for example) must write out headers with a write() call first and then
3221	* use sendfile to send out the data parts.
3222	*
3223	* TCP_CORK can be set together with TCP_NODELAY and it is stronger than
3224	* TCP_NODELAY.
3225	*/
3226	void __tcp_sock_set_cork(struct sock *sk, bool on)
3227	{
3228	struct tcp_sock *tp = tcp_sk(sk);
3229
3230	if (on) {
3231	tp->nonagle |= TCP_NAGLE_CORK;
3232	} else {
3233	tp->nonagle &= ~TCP_NAGLE_CORK;
3234	if (tp->nonagle & TCP_NAGLE_OFF)
3235	tp->nonagle |= TCP_NAGLE_PUSH;
3236	tcp_push_pending_frames(sk);
3237	}
3238	}
3239
3240	void tcp_sock_set_cork(struct sock *sk, bool on)
3241	{
3242	lock_sock(sk);
3243	__tcp_sock_set_cork(sk, on);
3244	release_sock(sk);
3245	}
3246	EXPORT_SYMBOL(tcp_sock_set_cork);
3247
3248	/* TCP_NODELAY is weaker than TCP_CORK, so that this option on corked socket is
3249	* remembered, but it is not activated until cork is cleared.
3250	*
3251	* However, when TCP_NODELAY is set we make an explicit push, which overrides
3252	* even TCP_CORK for currently queued segments.
3253	*/
3254	void __tcp_sock_set_nodelay(struct sock *sk, bool on)
3255	{
3256	if (on) {
3257	tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
3258	tcp_push_pending_frames(sk);
3259	} else {
3260	tcp_sk(sk)->nonagle &= ~TCP_NAGLE_OFF;
3261	}
3262	}
3263
3264	void tcp_sock_set_nodelay(struct sock *sk)
3265	{
3266	lock_sock(sk);
3267	__tcp_sock_set_nodelay(sk, on: true);
3268	release_sock(sk);
3269	}
3270	EXPORT_SYMBOL(tcp_sock_set_nodelay);
3271
3272	static void __tcp_sock_set_quickack(struct sock *sk, int val)
3273	{
3274	if (!val) {
3275	inet_csk_enter_pingpong_mode(sk);
3276	return;
3277	}
3278
3279	inet_csk_exit_pingpong_mode(sk);
3280	if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
3281	inet_csk_ack_scheduled(sk)) {
3282	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_PUSHED;
3283	tcp_cleanup_rbuf(sk, copied: 1);
3284	if (!(val & 1))
3285	inet_csk_enter_pingpong_mode(sk);
3286	}
3287	}
3288
3289	void tcp_sock_set_quickack(struct sock *sk, int val)
3290	{
3291	lock_sock(sk);
3292	__tcp_sock_set_quickack(sk, val);
3293	release_sock(sk);
3294	}
3295	EXPORT_SYMBOL(tcp_sock_set_quickack);
3296
3297	int tcp_sock_set_syncnt(struct sock *sk, int val)
3298	{
3299	if (val < 1 || val > MAX_TCP_SYNCNT)
3300	return -EINVAL;
3301
3302	WRITE_ONCE(inet_csk(sk)->icsk_syn_retries, val);
3303	return 0;
3304	}
3305	EXPORT_SYMBOL(tcp_sock_set_syncnt);
3306
3307	int tcp_sock_set_user_timeout(struct sock *sk, int val)
3308	{
3309	/* Cap the max time in ms TCP will retry or probe the window
3310	* before giving up and aborting (ETIMEDOUT) a connection.
3311	*/
3312	if (val < 0)
3313	return -EINVAL;
3314
3315	WRITE_ONCE(inet_csk(sk)->icsk_user_timeout, val);
3316	return 0;
3317	}
3318	EXPORT_SYMBOL(tcp_sock_set_user_timeout);
3319
3320	int tcp_sock_set_keepidle_locked(struct sock *sk, int val)
3321	{
3322	struct tcp_sock *tp = tcp_sk(sk);
3323
3324	if (val < 1 || val > MAX_TCP_KEEPIDLE)
3325	return -EINVAL;
3326
3327	/* Paired with WRITE_ONCE() in keepalive_time_when() */
3328	WRITE_ONCE(tp->keepalive_time, val * HZ);
3329	if (sock_flag(sk, flag: SOCK_KEEPOPEN) &&
3330	!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
3331	u32 elapsed = keepalive_time_elapsed(tp);
3332
3333	if (tp->keepalive_time > elapsed)
3334	elapsed = tp->keepalive_time - elapsed;
3335	else
3336	elapsed = 0;
3337	inet_csk_reset_keepalive_timer(sk, timeout: elapsed);
3338	}
3339
3340	return 0;
3341	}
3342
3343	int tcp_sock_set_keepidle(struct sock *sk, int val)
3344	{
3345	int err;
3346
3347	lock_sock(sk);
3348	err = tcp_sock_set_keepidle_locked(sk, val);
3349	release_sock(sk);
3350	return err;
3351	}
3352	EXPORT_SYMBOL(tcp_sock_set_keepidle);
3353
3354	int tcp_sock_set_keepintvl(struct sock *sk, int val)
3355	{
3356	if (val < 1 || val > MAX_TCP_KEEPINTVL)
3357	return -EINVAL;
3358
3359	WRITE_ONCE(tcp_sk(sk)->keepalive_intvl, val * HZ);
3360	return 0;
3361	}
3362	EXPORT_SYMBOL(tcp_sock_set_keepintvl);
3363
3364	int tcp_sock_set_keepcnt(struct sock *sk, int val)
3365	{
3366	if (val < 1 || val > MAX_TCP_KEEPCNT)
3367	return -EINVAL;
3368
3369	/* Paired with READ_ONCE() in keepalive_probes() */
3370	WRITE_ONCE(tcp_sk(sk)->keepalive_probes, val);
3371	return 0;
3372	}
3373	EXPORT_SYMBOL(tcp_sock_set_keepcnt);
3374
3375	int tcp_set_window_clamp(struct sock *sk, int val)
3376	{
3377	struct tcp_sock *tp = tcp_sk(sk);
3378
3379	if (!val) {
3380	if (sk->sk_state != TCP_CLOSE)
3381	return -EINVAL;
3382	tp->window_clamp = 0;
3383	} else {
3384	u32 new_rcv_ssthresh, old_window_clamp = tp->window_clamp;
3385	u32 new_window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
3386	SOCK_MIN_RCVBUF / 2 : val;
3387
3388	if (new_window_clamp == old_window_clamp)
3389	return 0;
3390
3391	tp->window_clamp = new_window_clamp;
3392	if (new_window_clamp < old_window_clamp) {
3393	/* need to apply the reserved mem provisioning only
3394	* when shrinking the window clamp
3395	*/
3396	__tcp_adjust_rcv_ssthresh(sk, new_ssthresh: tp->window_clamp);
3397
3398	} else {
3399	new_rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp);
3400	tp->rcv_ssthresh = max(new_rcv_ssthresh,
3401	tp->rcv_ssthresh);
3402	}
3403	}
3404	return 0;
3405	}
3406
3407	/*
3408	* Socket option code for TCP.
3409	*/
3410	int do_tcp_setsockopt(struct sock *sk, int level, int optname,
3411	sockptr_t optval, unsigned int optlen)
3412	{
3413	struct tcp_sock *tp = tcp_sk(sk);
3414	struct inet_connection_sock *icsk = inet_csk(sk);
3415	struct net *net = sock_net(sk);
3416	int val;
3417	int err = 0;
3418
3419	/* These are data/string values, all the others are ints */
3420	switch (optname) {
3421	case TCP_CONGESTION: {
3422	char name[TCP_CA_NAME_MAX];
3423
3424	if (optlen < 1)
3425	return -EINVAL;
3426
3427	val = strncpy_from_sockptr(dst: name, src: optval,
3428	min_t(long, TCP_CA_NAME_MAX-1, optlen));
3429	if (val < 0)
3430	return -EFAULT;
3431	name[val] = 0;
3432
3433	sockopt_lock_sock(sk);
3434	err = tcp_set_congestion_control(sk, name, load: !has_current_bpf_ctx(),
3435	cap_net_admin: sockopt_ns_capable(ns: sock_net(sk)->user_ns,
3436	CAP_NET_ADMIN));
3437	sockopt_release_sock(sk);
3438	return err;
3439	}
3440	case TCP_ULP: {
3441	char name[TCP_ULP_NAME_MAX];
3442
3443	if (optlen < 1)
3444	return -EINVAL;
3445
3446	val = strncpy_from_sockptr(dst: name, src: optval,
3447	min_t(long, TCP_ULP_NAME_MAX - 1,
3448	optlen));
3449	if (val < 0)
3450	return -EFAULT;
3451	name[val] = 0;
3452
3453	sockopt_lock_sock(sk);
3454	err = tcp_set_ulp(sk, name);
3455	sockopt_release_sock(sk);
3456	return err;
3457	}
3458	case TCP_FASTOPEN_KEY: {
3459	__u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
3460	__u8 *backup_key = NULL;
3461
3462	/* Allow a backup key as well to facilitate key rotation
3463	* First key is the active one.
3464	*/
3465	if (optlen != TCP_FASTOPEN_KEY_LENGTH &&
3466	optlen != TCP_FASTOPEN_KEY_BUF_LENGTH)
3467	return -EINVAL;
3468
3469	if (copy_from_sockptr(dst: key, src: optval, size: optlen))
3470	return -EFAULT;
3471
3472	if (optlen == TCP_FASTOPEN_KEY_BUF_LENGTH)
3473	backup_key = key + TCP_FASTOPEN_KEY_LENGTH;
3474
3475	return tcp_fastopen_reset_cipher(net, sk, primary_key: key, backup_key);
3476	}
3477	default:
3478	/* fallthru */
3479	break;
3480	}
3481
3482	if (optlen < sizeof(int))
3483	return -EINVAL;
3484
3485	if (copy_from_sockptr(dst: &val, src: optval, size: sizeof(val)))
3486	return -EFAULT;
3487
3488	/* Handle options that can be set without locking the socket. */
3489	switch (optname) {
3490	case TCP_SYNCNT:
3491	return tcp_sock_set_syncnt(sk, val);
3492	case TCP_USER_TIMEOUT:
3493	return tcp_sock_set_user_timeout(sk, val);
3494	case TCP_KEEPINTVL:
3495	return tcp_sock_set_keepintvl(sk, val);
3496	case TCP_KEEPCNT:
3497	return tcp_sock_set_keepcnt(sk, val);
3498	case TCP_LINGER2:
3499	if (val < 0)
3500	WRITE_ONCE(tp->linger2, -1);
3501	else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
3502	WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
3503	else
3504	WRITE_ONCE(tp->linger2, val * HZ);
3505	return 0;
3506	case TCP_DEFER_ACCEPT:
3507	/* Translate value in seconds to number of retransmits */
3508	WRITE_ONCE(icsk->icsk_accept_queue.rskq_defer_accept,
3509	secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
3510	TCP_RTO_MAX / HZ));
3511	return 0;
3512	}
3513
3514	sockopt_lock_sock(sk);
3515
3516	switch (optname) {
3517	case TCP_MAXSEG:
3518	/* Values greater than interface MTU won't take effect. However
3519	* at the point when this call is done we typically don't yet
3520	* know which interface is going to be used
3521	*/
3522	if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
3523	err = -EINVAL;
3524	break;
3525	}
3526	tp->rx_opt.user_mss = val;
3527	break;
3528
3529	case TCP_NODELAY:
3530	__tcp_sock_set_nodelay(sk, on: val);
3531	break;
3532
3533	case TCP_THIN_LINEAR_TIMEOUTS:
3534	if (val < 0 || val > 1)
3535	err = -EINVAL;
3536	else
3537	tp->thin_lto = val;
3538	break;
3539
3540	case TCP_THIN_DUPACK:
3541	if (val < 0 || val > 1)
3542	err = -EINVAL;
3543	break;
3544
3545	case TCP_REPAIR:
3546	if (!tcp_can_repair_sock(sk))
3547	err = -EPERM;
3548	else if (val == TCP_REPAIR_ON) {
3549	tp->repair = 1;
3550	sk->sk_reuse = SK_FORCE_REUSE;
3551	tp->repair_queue = TCP_NO_QUEUE;
3552	} else if (val == TCP_REPAIR_OFF) {
3553	tp->repair = 0;
3554	sk->sk_reuse = SK_NO_REUSE;
3555	tcp_send_window_probe(sk);
3556	} else if (val == TCP_REPAIR_OFF_NO_WP) {
3557	tp->repair = 0;
3558	sk->sk_reuse = SK_NO_REUSE;
3559	} else
3560	err = -EINVAL;
3561
3562	break;
3563
3564	case TCP_REPAIR_QUEUE:
3565	if (!tp->repair)
3566	err = -EPERM;
3567	else if ((unsigned int)val < TCP_QUEUES_NR)
3568	tp->repair_queue = val;
3569	else
3570	err = -EINVAL;
3571	break;
3572
3573	case TCP_QUEUE_SEQ:
3574	if (sk->sk_state != TCP_CLOSE) {
3575	err = -EPERM;
3576	} else if (tp->repair_queue == TCP_SEND_QUEUE) {
3577	if (!tcp_rtx_queue_empty(sk))
3578	err = -EPERM;
3579	else
3580	WRITE_ONCE(tp->write_seq, val);
3581	} else if (tp->repair_queue == TCP_RECV_QUEUE) {
3582	if (tp->rcv_nxt != tp->copied_seq) {
3583	err = -EPERM;
3584	} else {
3585	WRITE_ONCE(tp->rcv_nxt, val);
3586	WRITE_ONCE(tp->copied_seq, val);
3587	}
3588	} else {
3589	err = -EINVAL;
3590	}
3591	break;
3592
3593	case TCP_REPAIR_OPTIONS:
3594	if (!tp->repair)
3595	err = -EINVAL;
3596	else if (sk->sk_state == TCP_ESTABLISHED && !tp->bytes_sent)
3597	err = tcp_repair_options_est(sk, optbuf: optval, len: optlen);
3598	else
3599	err = -EPERM;
3600	break;
3601
3602	case TCP_CORK:
3603	__tcp_sock_set_cork(sk, on: val);
3604	break;
3605
3606	case TCP_KEEPIDLE:
3607	err = tcp_sock_set_keepidle_locked(sk, val);
3608	break;
3609	case TCP_SAVE_SYN:
3610	/* 0: disable, 1: enable, 2: start from ether_header */
3611	if (val < 0 || val > 2)
3612	err = -EINVAL;
3613	else
3614	tp->save_syn = val;
3615	break;
3616
3617	case TCP_WINDOW_CLAMP:
3618	err = tcp_set_window_clamp(sk, val);
3619	break;
3620
3621	case TCP_QUICKACK:
3622	__tcp_sock_set_quickack(sk, val);
3623	break;
3624
3625	case TCP_AO_REPAIR:
3626	if (!tcp_can_repair_sock(sk)) {
3627	err = -EPERM;
3628	break;
3629	}
3630	err = tcp_ao_set_repair(sk, optval, optlen);
3631	break;
3632	#ifdef CONFIG_TCP_AO
3633	case TCP_AO_ADD_KEY:
3634	case TCP_AO_DEL_KEY:
3635	case TCP_AO_INFO: {
3636	/* If this is the first TCP-AO setsockopt() on the socket,
3637	* sk_state has to be LISTEN or CLOSE. Allow TCP_REPAIR
3638	* in any state.
3639	*/
3640	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
3641	goto ao_parse;
3642	if (rcu_dereference_protected(tcp_sk(sk)->ao_info,
3643	lockdep_sock_is_held(sk)))
3644	goto ao_parse;
3645	if (tp->repair)
3646	goto ao_parse;
3647	err = -EISCONN;
3648	break;
3649	ao_parse:
3650	err = tp->af_specific->ao_parse(sk, optname, optval, optlen);
3651	break;
3652	}
3653	#endif
3654	#ifdef CONFIG_TCP_MD5SIG
3655	case TCP_MD5SIG:
3656	case TCP_MD5SIG_EXT:
3657	err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
3658	break;
3659	#endif
3660	case TCP_FASTOPEN:
3661	if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
3662	TCPF_LISTEN))) {
3663	tcp_fastopen_init_key_once(net);
3664
3665	fastopen_queue_tune(sk, backlog: val);
3666	} else {
3667	err = -EINVAL;
3668	}
3669	break;
3670	case TCP_FASTOPEN_CONNECT:
3671	if (val > 1 || val < 0) {
3672	err = -EINVAL;
3673	} else if (READ_ONCE(net->ipv4.sysctl_tcp_fastopen) &
3674	TFO_CLIENT_ENABLE) {
3675	if (sk->sk_state == TCP_CLOSE)
3676	tp->fastopen_connect = val;
3677	else
3678	err = -EINVAL;
3679	} else {
3680	err = -EOPNOTSUPP;
3681	}
3682	break;
3683	case TCP_FASTOPEN_NO_COOKIE:
3684	if (val > 1 || val < 0)
3685	err = -EINVAL;
3686	else if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
3687	err = -EINVAL;
3688	else
3689	tp->fastopen_no_cookie = val;
3690	break;
3691	case TCP_TIMESTAMP:
3692	if (!tp->repair) {
3693	err = -EPERM;
3694	break;
3695	}
3696	/* val is an opaque field,
3697	* and low order bit contains usec_ts enable bit.
3698	* Its a best effort, and we do not care if user makes an error.
3699	*/
3700	tp->tcp_usec_ts = val & 1;
3701	WRITE_ONCE(tp->tsoffset, val - tcp_clock_ts(tp->tcp_usec_ts));
3702	break;
3703	case TCP_REPAIR_WINDOW:
3704	err = tcp_repair_set_window(tp, optbuf: optval, len: optlen);
3705	break;
3706	case TCP_NOTSENT_LOWAT:
3707	WRITE_ONCE(tp->notsent_lowat, val);
3708	sk->sk_write_space(sk);
3709	break;
3710	case TCP_INQ:
3711	if (val > 1 || val < 0)
3712	err = -EINVAL;
3713	else
3714	tp->recvmsg_inq = val;
3715	break;
3716	case TCP_TX_DELAY:
3717	if (val)
3718	tcp_enable_tx_delay();
3719	WRITE_ONCE(tp->tcp_tx_delay, val);
3720	break;
3721	default:
3722	err = -ENOPROTOOPT;
3723	break;
3724	}
3725
3726	sockopt_release_sock(sk);
3727	return err;
3728	}
3729
3730	int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
3731	unsigned int optlen)
3732	{
3733	const struct inet_connection_sock *icsk = inet_csk(sk);
3734
3735	if (level != SOL_TCP)
3736	/* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */
3737	return READ_ONCE(icsk->icsk_af_ops)->setsockopt(sk, level, optname,
3738	optval, optlen);
3739	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
3740	}
3741	EXPORT_SYMBOL(tcp_setsockopt);
3742
3743	static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
3744	struct tcp_info *info)
3745	{
3746	u64 stats[__TCP_CHRONO_MAX], total = 0;
3747	enum tcp_chrono i;
3748
3749	for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
3750	stats[i] = tp->chrono_stat[i - 1];
3751	if (i == tp->chrono_type)
3752	stats[i] += tcp_jiffies32 - tp->chrono_start;
3753	stats[i] *= USEC_PER_SEC / HZ;
3754	total += stats[i];
3755	}
3756
3757	info->tcpi_busy_time = total;
3758	info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED];
3759	info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED];
3760	}
3761
3762	/* Return information about state of tcp endpoint in API format. */
3763	void tcp_get_info(struct sock *sk, struct tcp_info *info)
3764	{
3765	const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
3766	const struct inet_connection_sock *icsk = inet_csk(sk);
3767	unsigned long rate;
3768	u32 now;
3769	u64 rate64;
3770	bool slow;
3771
3772	memset(info, 0, sizeof(*info));
3773	if (sk->sk_type != SOCK_STREAM)
3774	return;
3775
3776	info->tcpi_state = inet_sk_state_load(sk);
3777
3778	/* Report meaningful fields for all TCP states, including listeners */
3779	rate = READ_ONCE(sk->sk_pacing_rate);
3780	rate64 = (rate != ~0UL) ? rate : ~0ULL;
3781	info->tcpi_pacing_rate = rate64;
3782
3783	rate = READ_ONCE(sk->sk_max_pacing_rate);
3784	rate64 = (rate != ~0UL) ? rate : ~0ULL;
3785	info->tcpi_max_pacing_rate = rate64;
3786
3787	info->tcpi_reordering = tp->reordering;
3788	info->tcpi_snd_cwnd = tcp_snd_cwnd(tp);
3789
3790	if (info->tcpi_state == TCP_LISTEN) {
3791	/* listeners aliased fields :
3792	* tcpi_unacked -> Number of children ready for accept()
3793	* tcpi_sacked -> max backlog
3794	*/
3795	info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog);
3796	info->tcpi_sacked = READ_ONCE(sk->sk_max_ack_backlog);
3797	return;
3798	}
3799
3800	slow = lock_sock_fast(sk);
3801
3802	info->tcpi_ca_state = icsk->icsk_ca_state;
3803	info->tcpi_retransmits = icsk->icsk_retransmits;
3804	info->tcpi_probes = icsk->icsk_probes_out;
3805	info->tcpi_backoff = icsk->icsk_backoff;
3806
3807	if (tp->rx_opt.tstamp_ok)
3808	info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
3809	if (tcp_is_sack(tp))
3810	info->tcpi_options |= TCPI_OPT_SACK;
3811	if (tp->rx_opt.wscale_ok) {
3812	info->tcpi_options |= TCPI_OPT_WSCALE;
3813	info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
3814	info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
3815	}
3816
3817	if (tp->ecn_flags & TCP_ECN_OK)
3818	info->tcpi_options |= TCPI_OPT_ECN;
3819	if (tp->ecn_flags & TCP_ECN_SEEN)
3820	info->tcpi_options |= TCPI_OPT_ECN_SEEN;
3821	if (tp->syn_data_acked)
3822	info->tcpi_options |= TCPI_OPT_SYN_DATA;
3823	if (tp->tcp_usec_ts)
3824	info->tcpi_options |= TCPI_OPT_USEC_TS;
3825
3826	info->tcpi_rto = jiffies_to_usecs(j: icsk->icsk_rto);
3827	info->tcpi_ato = jiffies_to_usecs(min_t(u32, icsk->icsk_ack.ato,
3828	tcp_delack_max(sk)));
3829	info->tcpi_snd_mss = tp->mss_cache;
3830	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
3831
3832	info->tcpi_unacked = tp->packets_out;
3833	info->tcpi_sacked = tp->sacked_out;
3834
3835	info->tcpi_lost = tp->lost_out;
3836	info->tcpi_retrans = tp->retrans_out;
3837
3838	now = tcp_jiffies32;
3839	info->tcpi_last_data_sent = jiffies_to_msecs(j: now - tp->lsndtime);
3840	info->tcpi_last_data_recv = jiffies_to_msecs(j: now - icsk->icsk_ack.lrcvtime);
3841	info->tcpi_last_ack_recv = jiffies_to_msecs(j: now - tp->rcv_tstamp);
3842
3843	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
3844	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
3845	info->tcpi_rtt = tp->srtt_us >> 3;
3846	info->tcpi_rttvar = tp->mdev_us >> 2;
3847	info->tcpi_snd_ssthresh = tp->snd_ssthresh;
3848	info->tcpi_advmss = tp->advmss;
3849
3850	info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
3851	info->tcpi_rcv_space = tp->rcvq_space.space;
3852
3853	info->tcpi_total_retrans = tp->total_retrans;
3854
3855	info->tcpi_bytes_acked = tp->bytes_acked;
3856	info->tcpi_bytes_received = tp->bytes_received;
3857	info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
3858	tcp_get_info_chrono_stats(tp, info);
3859
3860	info->tcpi_segs_out = tp->segs_out;
3861
3862	/* segs_in and data_segs_in can be updated from tcp_segs_in() from BH */
3863	info->tcpi_segs_in = READ_ONCE(tp->segs_in);
3864	info->tcpi_data_segs_in = READ_ONCE(tp->data_segs_in);
3865
3866	info->tcpi_min_rtt = tcp_min_rtt(tp);
3867	info->tcpi_data_segs_out = tp->data_segs_out;
3868
3869	info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
3870	rate64 = tcp_compute_delivery_rate(tp);
3871	if (rate64)
3872	info->tcpi_delivery_rate = rate64;
3873	info->tcpi_delivered = tp->delivered;
3874	info->tcpi_delivered_ce = tp->delivered_ce;
3875	info->tcpi_bytes_sent = tp->bytes_sent;
3876	info->tcpi_bytes_retrans = tp->bytes_retrans;
3877	info->tcpi_dsack_dups = tp->dsack_dups;
3878	info->tcpi_reord_seen = tp->reord_seen;
3879	info->tcpi_rcv_ooopack = tp->rcv_ooopack;
3880	info->tcpi_snd_wnd = tp->snd_wnd;
3881	info->tcpi_rcv_wnd = tp->rcv_wnd;
3882	info->tcpi_rehash = tp->plb_rehash + tp->timeout_rehash;
3883	info->tcpi_fastopen_client_fail = tp->fastopen_client_fail;
3884
3885	info->tcpi_total_rto = tp->total_rto;
3886	info->tcpi_total_rto_recoveries = tp->total_rto_recoveries;
3887	info->tcpi_total_rto_time = tp->total_rto_time;
3888	if (tp->rto_stamp)
3889	info->tcpi_total_rto_time += tcp_clock_ms() - tp->rto_stamp;
3890
3891	unlock_sock_fast(sk, slow);
3892	}
3893	EXPORT_SYMBOL_GPL(tcp_get_info);
3894
3895	static size_t tcp_opt_stats_get_size(void)
3896	{
3897	return
3898	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_BUSY */
3899	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */
3900	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */
3901	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */
3902	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */
3903	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_PACING_RATE */
3904	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */
3905	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_SND_CWND */
3906	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_REORDERING */
3907	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_MIN_RTT */
3908	nla_total_size(payload: sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */
3909	nla_total_size(payload: sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */
3910	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */
3911	nla_total_size(payload: sizeof(u8)) + /* TCP_NLA_CA_STATE */
3912	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */
3913	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_DELIVERED */
3914	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
3915	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_BYTES_SENT */
3916	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
3917	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */
3918	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_REORD_SEEN */
3919	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_SRTT */
3920	nla_total_size(payload: sizeof(u16)) + /* TCP_NLA_TIMEOUT_REHASH */
3921	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_BYTES_NOTSENT */
3922	nla_total_size_64bit(payload: sizeof(u64)) + /* TCP_NLA_EDT */
3923	nla_total_size(payload: sizeof(u8)) + /* TCP_NLA_TTL */
3924	nla_total_size(payload: sizeof(u32)) + /* TCP_NLA_REHASH */
3925	0;
3926	}
3927
3928	/* Returns TTL or hop limit of an incoming packet from skb. */
3929	static u8 tcp_skb_ttl_or_hop_limit(const struct sk_buff *skb)
3930	{
3931	if (skb->protocol == htons(ETH_P_IP))
3932	return ip_hdr(skb)->ttl;
3933	else if (skb->protocol == htons(ETH_P_IPV6))
3934	return ipv6_hdr(skb)->hop_limit;
3935	else
3936	return 0;
3937	}
3938
3939	struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
3940	const struct sk_buff *orig_skb,
3941	const struct sk_buff *ack_skb)
3942	{
3943	const struct tcp_sock *tp = tcp_sk(sk);
3944	struct sk_buff *stats;
3945	struct tcp_info info;
3946	unsigned long rate;
3947	u64 rate64;
3948
3949	stats = alloc_skb(size: tcp_opt_stats_get_size(), GFP_ATOMIC);
3950	if (!stats)
3951	return NULL;
3952
3953	tcp_get_info_chrono_stats(tp, info: &info);
3954	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_BUSY,
3955	value: info.tcpi_busy_time, padattr: TCP_NLA_PAD);
3956	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_RWND_LIMITED,
3957	value: info.tcpi_rwnd_limited, padattr: TCP_NLA_PAD);
3958	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_SNDBUF_LIMITED,
3959	value: info.tcpi_sndbuf_limited, padattr: TCP_NLA_PAD);
3960	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_DATA_SEGS_OUT,
3961	value: tp->data_segs_out, padattr: TCP_NLA_PAD);
3962	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_TOTAL_RETRANS,
3963	value: tp->total_retrans, padattr: TCP_NLA_PAD);
3964
3965	rate = READ_ONCE(sk->sk_pacing_rate);
3966	rate64 = (rate != ~0UL) ? rate : ~0ULL;
3967	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_PACING_RATE, value: rate64, padattr: TCP_NLA_PAD);
3968
3969	rate64 = tcp_compute_delivery_rate(tp);
3970	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_DELIVERY_RATE, value: rate64, padattr: TCP_NLA_PAD);
3971
3972	nla_put_u32(skb: stats, attrtype: TCP_NLA_SND_CWND, value: tcp_snd_cwnd(tp));
3973	nla_put_u32(skb: stats, attrtype: TCP_NLA_REORDERING, value: tp->reordering);
3974	nla_put_u32(skb: stats, attrtype: TCP_NLA_MIN_RTT, value: tcp_min_rtt(tp));
3975
3976	nla_put_u8(skb: stats, attrtype: TCP_NLA_RECUR_RETRANS, value: inet_csk(sk)->icsk_retransmits);
3977	nla_put_u8(skb: stats, attrtype: TCP_NLA_DELIVERY_RATE_APP_LMT, value: !!tp->rate_app_limited);
3978	nla_put_u32(skb: stats, attrtype: TCP_NLA_SND_SSTHRESH, value: tp->snd_ssthresh);
3979	nla_put_u32(skb: stats, attrtype: TCP_NLA_DELIVERED, value: tp->delivered);
3980	nla_put_u32(skb: stats, attrtype: TCP_NLA_DELIVERED_CE, value: tp->delivered_ce);
3981
3982	nla_put_u32(skb: stats, attrtype: TCP_NLA_SNDQ_SIZE, value: tp->write_seq - tp->snd_una);
3983	nla_put_u8(skb: stats, attrtype: TCP_NLA_CA_STATE, value: inet_csk(sk)->icsk_ca_state);
3984
3985	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_BYTES_SENT, value: tp->bytes_sent,
3986	padattr: TCP_NLA_PAD);
3987	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_BYTES_RETRANS, value: tp->bytes_retrans,
3988	padattr: TCP_NLA_PAD);
3989	nla_put_u32(skb: stats, attrtype: TCP_NLA_DSACK_DUPS, value: tp->dsack_dups);
3990	nla_put_u32(skb: stats, attrtype: TCP_NLA_REORD_SEEN, value: tp->reord_seen);
3991	nla_put_u32(skb: stats, attrtype: TCP_NLA_SRTT, value: tp->srtt_us >> 3);
3992	nla_put_u16(skb: stats, attrtype: TCP_NLA_TIMEOUT_REHASH, value: tp->timeout_rehash);
3993	nla_put_u32(skb: stats, attrtype: TCP_NLA_BYTES_NOTSENT,
3994	max_t(int, 0, tp->write_seq - tp->snd_nxt));
3995	nla_put_u64_64bit(skb: stats, attrtype: TCP_NLA_EDT, value: orig_skb->skb_mstamp_ns,
3996	padattr: TCP_NLA_PAD);
3997	if (ack_skb)
3998	nla_put_u8(skb: stats, attrtype: TCP_NLA_TTL,
3999	value: tcp_skb_ttl_or_hop_limit(skb: ack_skb));
4000
4001	nla_put_u32(skb: stats, attrtype: TCP_NLA_REHASH, value: tp->plb_rehash + tp->timeout_rehash);
4002	return stats;
4003	}
4004
4005	int do_tcp_getsockopt(struct sock *sk, int level,
4006	int optname, sockptr_t optval, sockptr_t optlen)
4007	{
4008	struct inet_connection_sock *icsk = inet_csk(sk);
4009	struct tcp_sock *tp = tcp_sk(sk);
4010	struct net *net = sock_net(sk);
4011	int val, len;
4012
4013	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4014	return -EFAULT;
4015
4016	if (len < 0)
4017	return -EINVAL;
4018
4019	len = min_t(unsigned int, len, sizeof(int));
4020
4021	switch (optname) {
4022	case TCP_MAXSEG:
4023	val = tp->mss_cache;
4024	if (tp->rx_opt.user_mss &&
4025	((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
4026	val = tp->rx_opt.user_mss;
4027	if (tp->repair)
4028	val = tp->rx_opt.mss_clamp;
4029	break;
4030	case TCP_NODELAY:
4031	val = !!(tp->nonagle&TCP_NAGLE_OFF);
4032	break;
4033	case TCP_CORK:
4034	val = !!(tp->nonagle&TCP_NAGLE_CORK);
4035	break;
4036	case TCP_KEEPIDLE:
4037	val = keepalive_time_when(tp) / HZ;
4038	break;
4039	case TCP_KEEPINTVL:
4040	val = keepalive_intvl_when(tp) / HZ;
4041	break;
4042	case TCP_KEEPCNT:
4043	val = keepalive_probes(tp);
4044	break;
4045	case TCP_SYNCNT:
4046	val = READ_ONCE(icsk->icsk_syn_retries) ? :
4047	READ_ONCE(net->ipv4.sysctl_tcp_syn_retries);
4048	break;
4049	case TCP_LINGER2:
4050	val = READ_ONCE(tp->linger2);
4051	if (val >= 0)
4052	val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ;
4053	break;
4054	case TCP_DEFER_ACCEPT:
4055	val = READ_ONCE(icsk->icsk_accept_queue.rskq_defer_accept);
4056	val = retrans_to_secs(retrans: val, TCP_TIMEOUT_INIT / HZ,
4057	TCP_RTO_MAX / HZ);
4058	break;
4059	case TCP_WINDOW_CLAMP:
4060	val = tp->window_clamp;
4061	break;
4062	case TCP_INFO: {
4063	struct tcp_info info;
4064
4065	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4066	return -EFAULT;
4067
4068	tcp_get_info(sk, &info);
4069
4070	len = min_t(unsigned int, len, sizeof(info));
4071	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4072	return -EFAULT;
4073	if (copy_to_sockptr(dst: optval, src: &info, size: len))
4074	return -EFAULT;
4075	return 0;
4076	}
4077	case TCP_CC_INFO: {
4078	const struct tcp_congestion_ops *ca_ops;
4079	union tcp_cc_info info;
4080	size_t sz = 0;
4081	int attr;
4082
4083	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4084	return -EFAULT;
4085
4086	ca_ops = icsk->icsk_ca_ops;
4087	if (ca_ops && ca_ops->get_info)
4088	sz = ca_ops->get_info(sk, ~0U, &attr, &info);
4089
4090	len = min_t(unsigned int, len, sz);
4091	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4092	return -EFAULT;
4093	if (copy_to_sockptr(dst: optval, src: &info, size: len))
4094	return -EFAULT;
4095	return 0;
4096	}
4097	case TCP_QUICKACK:
4098	val = !inet_csk_in_pingpong_mode(sk);
4099	break;
4100
4101	case TCP_CONGESTION:
4102	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4103	return -EFAULT;
4104	len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
4105	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4106	return -EFAULT;
4107	if (copy_to_sockptr(dst: optval, src: icsk->icsk_ca_ops->name, size: len))
4108	return -EFAULT;
4109	return 0;
4110
4111	case TCP_ULP:
4112	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4113	return -EFAULT;
4114	len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
4115	if (!icsk->icsk_ulp_ops) {
4116	len = 0;
4117	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4118	return -EFAULT;
4119	return 0;
4120	}
4121	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4122	return -EFAULT;
4123	if (copy_to_sockptr(dst: optval, src: icsk->icsk_ulp_ops->name, size: len))
4124	return -EFAULT;
4125	return 0;
4126
4127	case TCP_FASTOPEN_KEY: {
4128	u64 key[TCP_FASTOPEN_KEY_BUF_LENGTH / sizeof(u64)];
4129	unsigned int key_len;
4130
4131	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4132	return -EFAULT;
4133
4134	key_len = tcp_fastopen_get_cipher(net, icsk, key) *
4135	TCP_FASTOPEN_KEY_LENGTH;
4136	len = min_t(unsigned int, len, key_len);
4137	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4138	return -EFAULT;
4139	if (copy_to_sockptr(dst: optval, src: key, size: len))
4140	return -EFAULT;
4141	return 0;
4142	}
4143	case TCP_THIN_LINEAR_TIMEOUTS:
4144	val = tp->thin_lto;
4145	break;
4146
4147	case TCP_THIN_DUPACK:
4148	val = 0;
4149	break;
4150
4151	case TCP_REPAIR:
4152	val = tp->repair;
4153	break;
4154
4155	case TCP_REPAIR_QUEUE:
4156	if (tp->repair)
4157	val = tp->repair_queue;
4158	else
4159	return -EINVAL;
4160	break;
4161
4162	case TCP_REPAIR_WINDOW: {
4163	struct tcp_repair_window opt;
4164
4165	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4166	return -EFAULT;
4167
4168	if (len != sizeof(opt))
4169	return -EINVAL;
4170
4171	if (!tp->repair)
4172	return -EPERM;
4173
4174	opt.snd_wl1 = tp->snd_wl1;
4175	opt.snd_wnd = tp->snd_wnd;
4176	opt.max_window = tp->max_window;
4177	opt.rcv_wnd = tp->rcv_wnd;
4178	opt.rcv_wup = tp->rcv_wup;
4179
4180	if (copy_to_sockptr(dst: optval, src: &opt, size: len))
4181	return -EFAULT;
4182	return 0;
4183	}
4184	case TCP_QUEUE_SEQ:
4185	if (tp->repair_queue == TCP_SEND_QUEUE)
4186	val = tp->write_seq;
4187	else if (tp->repair_queue == TCP_RECV_QUEUE)
4188	val = tp->rcv_nxt;
4189	else
4190	return -EINVAL;
4191	break;
4192
4193	case TCP_USER_TIMEOUT:
4194	val = READ_ONCE(icsk->icsk_user_timeout);
4195	break;
4196
4197	case TCP_FASTOPEN:
4198	val = READ_ONCE(icsk->icsk_accept_queue.fastopenq.max_qlen);
4199	break;
4200
4201	case TCP_FASTOPEN_CONNECT:
4202	val = tp->fastopen_connect;
4203	break;
4204
4205	case TCP_FASTOPEN_NO_COOKIE:
4206	val = tp->fastopen_no_cookie;
4207	break;
4208
4209	case TCP_TX_DELAY:
4210	val = READ_ONCE(tp->tcp_tx_delay);
4211	break;
4212
4213	case TCP_TIMESTAMP:
4214	val = tcp_clock_ts(usec_ts: tp->tcp_usec_ts) + READ_ONCE(tp->tsoffset);
4215	if (tp->tcp_usec_ts)
4216	val |= 1;
4217	else
4218	val &= ~1;
4219	break;
4220	case TCP_NOTSENT_LOWAT:
4221	val = READ_ONCE(tp->notsent_lowat);
4222	break;
4223	case TCP_INQ:
4224	val = tp->recvmsg_inq;
4225	break;
4226	case TCP_SAVE_SYN:
4227	val = tp->save_syn;
4228	break;
4229	case TCP_SAVED_SYN: {
4230	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4231	return -EFAULT;
4232
4233	sockopt_lock_sock(sk);
4234	if (tp->saved_syn) {
4235	if (len < tcp_saved_syn_len(saved_syn: tp->saved_syn)) {
4236	len = tcp_saved_syn_len(saved_syn: tp->saved_syn);
4237	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int))) {
4238	sockopt_release_sock(sk);
4239	return -EFAULT;
4240	}
4241	sockopt_release_sock(sk);
4242	return -EINVAL;
4243	}
4244	len = tcp_saved_syn_len(saved_syn: tp->saved_syn);
4245	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int))) {
4246	sockopt_release_sock(sk);
4247	return -EFAULT;
4248	}
4249	if (copy_to_sockptr(dst: optval, src: tp->saved_syn->data, size: len)) {
4250	sockopt_release_sock(sk);
4251	return -EFAULT;
4252	}
4253	tcp_saved_syn_free(tp);
4254	sockopt_release_sock(sk);
4255	} else {
4256	sockopt_release_sock(sk);
4257	len = 0;
4258	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4259	return -EFAULT;
4260	}
4261	return 0;
4262	}
4263	#ifdef CONFIG_MMU
4264	case TCP_ZEROCOPY_RECEIVE: {
4265	struct scm_timestamping_internal tss;
4266	struct tcp_zerocopy_receive zc = {};
4267	int err;
4268
4269	if (copy_from_sockptr(dst: &len, src: optlen, size: sizeof(int)))
4270	return -EFAULT;
4271	if (len < 0 ||
4272	len < offsetofend(struct tcp_zerocopy_receive, length))
4273	return -EINVAL;
4274	if (unlikely(len > sizeof(zc))) {
4275	err = check_zeroed_sockptr(src: optval, offset: sizeof(zc),
4276	size: len - sizeof(zc));
4277	if (err < 1)
4278	return err == 0 ? -EINVAL : err;
4279	len = sizeof(zc);
4280	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4281	return -EFAULT;
4282	}
4283	if (copy_from_sockptr(dst: &zc, src: optval, size: len))
4284	return -EFAULT;
4285	if (zc.reserved)
4286	return -EINVAL;
4287	if (zc.msg_flags & ~(TCP_VALID_ZC_MSG_FLAGS))
4288	return -EINVAL;
4289	sockopt_lock_sock(sk);
4290	err = tcp_zerocopy_receive(sk, zc: &zc, tss: &tss);
4291	err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
4292	&zc, &len, err);
4293	sockopt_release_sock(sk);
4294	if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))
4295	goto zerocopy_rcv_cmsg;
4296	switch (len) {
4297	case offsetofend(struct tcp_zerocopy_receive, msg_flags):
4298	goto zerocopy_rcv_cmsg;
4299	case offsetofend(struct tcp_zerocopy_receive, msg_controllen):
4300	case offsetofend(struct tcp_zerocopy_receive, msg_control):
4301	case offsetofend(struct tcp_zerocopy_receive, flags):
4302	case offsetofend(struct tcp_zerocopy_receive, copybuf_len):
4303	case offsetofend(struct tcp_zerocopy_receive, copybuf_address):
4304	case offsetofend(struct tcp_zerocopy_receive, err):
4305	goto zerocopy_rcv_sk_err;
4306	case offsetofend(struct tcp_zerocopy_receive, inq):
4307	goto zerocopy_rcv_inq;
4308	case offsetofend(struct tcp_zerocopy_receive, length):
4309	default:
4310	goto zerocopy_rcv_out;
4311	}
4312	zerocopy_rcv_cmsg:
4313	if (zc.msg_flags & TCP_CMSG_TS)
4314	tcp_zc_finalize_rx_tstamp(sk, zc: &zc, tss: &tss);
4315	else
4316	zc.msg_flags = 0;
4317	zerocopy_rcv_sk_err:
4318	if (!err)
4319	zc.err = sock_error(sk);
4320	zerocopy_rcv_inq:
4321	zc.inq = tcp_inq_hint(sk);
4322	zerocopy_rcv_out:
4323	if (!err && copy_to_sockptr(dst: optval, src: &zc, size: len))
4324	err = -EFAULT;
4325	return err;
4326	}
4327	#endif
4328	case TCP_AO_REPAIR:
4329	if (!tcp_can_repair_sock(sk))
4330	return -EPERM;
4331	return tcp_ao_get_repair(sk, optval, optlen);
4332	case TCP_AO_GET_KEYS:
4333	case TCP_AO_INFO: {
4334	int err;
4335
4336	sockopt_lock_sock(sk);
4337	if (optname == TCP_AO_GET_KEYS)
4338	err = tcp_ao_get_mkts(sk, optval, optlen);
4339	else
4340	err = tcp_ao_get_sock_info(sk, optval, optlen);
4341	sockopt_release_sock(sk);
4342
4343	return err;
4344	}
4345	default:
4346	return -ENOPROTOOPT;
4347	}
4348
4349	if (copy_to_sockptr(dst: optlen, src: &len, size: sizeof(int)))
4350	return -EFAULT;
4351	if (copy_to_sockptr(dst: optval, src: &val, size: len))
4352	return -EFAULT;
4353	return 0;
4354	}
4355
4356	bool tcp_bpf_bypass_getsockopt(int level, int optname)
4357	{
4358	/* TCP do_tcp_getsockopt has optimized getsockopt implementation
4359	* to avoid extra socket lock for TCP_ZEROCOPY_RECEIVE.
4360	*/
4361	if (level == SOL_TCP && optname == TCP_ZEROCOPY_RECEIVE)
4362	return true;
4363
4364	return false;
4365	}
4366	EXPORT_SYMBOL(tcp_bpf_bypass_getsockopt);
4367
4368	int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
4369	int __user *optlen)
4370	{
4371	struct inet_connection_sock *icsk = inet_csk(sk);
4372
4373	if (level != SOL_TCP)
4374	/* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */
4375	return READ_ONCE(icsk->icsk_af_ops)->getsockopt(sk, level, optname,
4376	optval, optlen);
4377	return do_tcp_getsockopt(sk, level, optname, optval: USER_SOCKPTR(p: optval),
4378	optlen: USER_SOCKPTR(p: optlen));
4379	}
4380	EXPORT_SYMBOL(tcp_getsockopt);
4381
4382	#ifdef CONFIG_TCP_MD5SIG
4383	int tcp_md5_sigpool_id = -1;
4384	EXPORT_SYMBOL_GPL(tcp_md5_sigpool_id);
4385
4386	int tcp_md5_alloc_sigpool(void)
4387	{
4388	size_t scratch_size;
4389	int ret;
4390
4391	scratch_size = sizeof(union tcp_md5sum_block) + sizeof(struct tcphdr);
4392	ret = tcp_sigpool_alloc_ahash(alg: "md5", scratch_size);
4393	if (ret >= 0) {
4394	/* As long as any md5 sigpool was allocated, the return
4395	* id would stay the same. Re-write the id only for the case
4396	* when previously all MD5 keys were deleted and this call
4397	* allocates the first MD5 key, which may return a different
4398	* sigpool id than was used previously.
4399	*/
4400	WRITE_ONCE(tcp_md5_sigpool_id, ret); /* Avoids the compiler potentially being smart here */
4401	return 0;
4402	}
4403	return ret;
4404	}
4405
4406	void tcp_md5_release_sigpool(void)
4407	{
4408	tcp_sigpool_release(READ_ONCE(tcp_md5_sigpool_id));
4409	}
4410
4411	void tcp_md5_add_sigpool(void)
4412	{
4413	tcp_sigpool_get(READ_ONCE(tcp_md5_sigpool_id));
4414	}
4415
4416	int tcp_md5_hash_key(struct tcp_sigpool *hp,
4417	const struct tcp_md5sig_key *key)
4418	{
4419	u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */
4420	struct scatterlist sg;
4421
4422	sg_init_one(&sg, key->key, keylen);
4423	ahash_request_set_crypt(req: hp->req, src: &sg, NULL, nbytes: keylen);
4424
4425	/* We use data_race() because tcp_md5_do_add() might change
4426	* key->key under us
4427	*/
4428	return data_race(crypto_ahash_update(hp->req));
4429	}
4430	EXPORT_SYMBOL(tcp_md5_hash_key);
4431
4432	/* Called with rcu_read_lock() */
4433	enum skb_drop_reason
4434	tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
4435	const void *saddr, const void *daddr,
4436	int family, int l3index, const __u8 *hash_location)
4437	{
4438	/* This gets called for each TCP segment that has TCP-MD5 option.
4439	* We have 3 drop cases:
4440	* o No MD5 hash and one expected.
4441	* o MD5 hash and we're not expecting one.
4442	* o MD5 hash and its wrong.
4443	*/
4444	const struct tcp_sock *tp = tcp_sk(sk);
4445	struct tcp_md5sig_key *key;
4446	u8 newhash[16];
4447	int genhash;
4448
4449	key = tcp_md5_do_lookup(sk, l3index, addr: saddr, family);
4450
4451	if (!key && hash_location) {
4452	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
4453	tcp_hash_fail("Unexpected MD5 Hash found", family, skb, "");
4454	return SKB_DROP_REASON_TCP_MD5UNEXPECTED;
4455	}
4456
4457	/* Check the signature.
4458	* To support dual stack listeners, we need to handle
4459	* IPv4-mapped case.
4460	*/
4461	if (family == AF_INET)
4462	genhash = tcp_v4_md5_hash_skb(md5_hash: newhash, key, NULL, skb);
4463	else
4464	genhash = tp->af_specific->calc_md5_hash(newhash, key,
4465	NULL, skb);
4466	if (genhash || memcmp(p: hash_location, q: newhash, size: 16) != 0) {
4467	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
4468	if (family == AF_INET) {
4469	tcp_hash_fail("MD5 Hash failed", AF_INET, skb, "%s L3 index %d",
4470	genhash ? "tcp_v4_calc_md5_hash failed"
4471	: "", l3index);
4472	} else {
4473	if (genhash) {
4474	tcp_hash_fail("MD5 Hash failed",
4475	AF_INET6, skb, "L3 index %d",
4476	l3index);
4477	} else {
4478	tcp_hash_fail("MD5 Hash mismatch",
4479	AF_INET6, skb, "L3 index %d",
4480	l3index);
4481	}
4482	}
4483	return SKB_DROP_REASON_TCP_MD5FAILURE;
4484	}
4485	return SKB_NOT_DROPPED_YET;
4486	}
4487	EXPORT_SYMBOL(tcp_inbound_md5_hash);
4488
4489	#endif
4490
4491	void tcp_done(struct sock *sk)
4492	{
4493	struct request_sock *req;
4494
4495	/* We might be called with a new socket, after
4496	* inet_csk_prepare_forced_close() has been called
4497	* so we can not use lockdep_sock_is_held(sk)
4498	*/
4499	req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk, 1);
4500
4501	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
4502	TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
4503
4504	tcp_set_state(sk, TCP_CLOSE);
4505	tcp_clear_xmit_timers(sk);
4506	if (req)
4507	reqsk_fastopen_remove(sk, req, reset: false);
4508
4509	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
4510
4511	if (!sock_flag(sk, flag: SOCK_DEAD))
4512	sk->sk_state_change(sk);
4513	else
4514	inet_csk_destroy_sock(sk);
4515	}
4516	EXPORT_SYMBOL_GPL(tcp_done);
4517
4518	int tcp_abort(struct sock *sk, int err)
4519	{
4520	int state = inet_sk_state_load(sk);
4521
4522	if (state == TCP_NEW_SYN_RECV) {
4523	struct request_sock *req = inet_reqsk(sk);
4524
4525	local_bh_disable();
4526	inet_csk_reqsk_queue_drop(sk: req->rsk_listener, req);
4527	local_bh_enable();
4528	return 0;
4529	}
4530	if (state == TCP_TIME_WAIT) {
4531	struct inet_timewait_sock *tw = inet_twsk(sk);
4532
4533	refcount_inc(r: &tw->tw_refcnt);
4534	local_bh_disable();
4535	inet_twsk_deschedule_put(tw);
4536	local_bh_enable();
4537	return 0;
4538	}
4539
4540	/* BPF context ensures sock locking. */
4541	if (!has_current_bpf_ctx())
4542	/* Don't race with userspace socket closes such as tcp_close. */
4543	lock_sock(sk);
4544
4545	if (sk->sk_state == TCP_LISTEN) {
4546	tcp_set_state(sk, TCP_CLOSE);
4547	inet_csk_listen_stop(sk);
4548	}
4549
4550	/* Don't race with BH socket closes such as inet_csk_listen_stop. */
4551	local_bh_disable();
4552	bh_lock_sock(sk);
4553
4554	if (!sock_flag(sk, flag: SOCK_DEAD)) {
4555	WRITE_ONCE(sk->sk_err, err);
4556	/* This barrier is coupled with smp_rmb() in tcp_poll() */
4557	smp_wmb();
4558	sk_error_report(sk);
4559	if (tcp_need_reset(state: sk->sk_state))
4560	tcp_send_active_reset(sk, GFP_ATOMIC);
4561	tcp_done(sk);
4562	}
4563
4564	bh_unlock_sock(sk);
4565	local_bh_enable();
4566	tcp_write_queue_purge(sk);
4567	if (!has_current_bpf_ctx())
4568	release_sock(sk);
4569	return 0;
4570	}
4571	EXPORT_SYMBOL_GPL(tcp_abort);
4572
4573	extern struct tcp_congestion_ops tcp_reno;
4574
4575	static __initdata unsigned long thash_entries;
4576	static int __init set_thash_entries(char *str)
4577	{
4578	ssize_t ret;
4579
4580	if (!str)
4581	return 0;
4582
4583	ret = kstrtoul(s: str, base: 0, res: &thash_entries);
4584	if (ret)
4585	return 0;
4586
4587	return 1;
4588	}
4589	__setup("thash_entries=", set_thash_entries);
4590
4591	static void __init tcp_init_mem(void)
4592	{
4593	unsigned long limit = nr_free_buffer_pages() / 16;
4594
4595	limit = max(limit, 128UL);
4596	sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
4597	sysctl_tcp_mem[1] = limit; /* 6.25 % */
4598	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
4599	}
4600
4601	static void __init tcp_struct_check(void)
4602	{
4603	/* TX read-mostly hotpath cache lines */
4604	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, max_window);
4605	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, rcv_ssthresh);
4606	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, reordering);
4607	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, notsent_lowat);
4608	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, gso_segs);
4609	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, lost_skb_hint);
4610	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, retransmit_skb_hint);
4611	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_tx, 40);
4612
4613	/* TXRX read-mostly hotpath cache lines */
4614	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, tsoffset);
4615	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, snd_wnd);
4616	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, mss_cache);
4617	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, snd_cwnd);
4618	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, prr_out);
4619	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, lost_out);
4620	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, sacked_out);
4621	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, scaling_ratio);
4622	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_txrx, 32);
4623
4624	/* RX read-mostly hotpath cache lines */
4625	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, copied_seq);
4626	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rcv_tstamp);
4627	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, snd_wl1);
4628	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, tlp_high_seq);
4629	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rttvar_us);
4630	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, retrans_out);
4631	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, advmss);
4632	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, urg_data);
4633	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, lost);
4634	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rtt_min);
4635	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, out_of_order_queue);
4636	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, snd_ssthresh);
4637	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_rx, 69);
4638
4639	/* TX read-write hotpath cache lines */
4640	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, segs_out);
4641	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, data_segs_out);
4642	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, bytes_sent);
4643	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, snd_sml);
4644	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, chrono_start);
4645	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, chrono_stat);
4646	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, write_seq);
4647	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, pushed_seq);
4648	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, lsndtime);
4649	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, mdev_us);
4650	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_wstamp_ns);
4651	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_clock_cache);
4652	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_mstamp);
4653	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, rtt_seq);
4654	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tsorted_sent_queue);
4655	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, highest_sack);
4656	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, ecn_flags);
4657	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_tx, 105);
4658
4659	/* TXRX read-write hotpath cache lines */
4660	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, pred_flags);
4661	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rcv_nxt);
4662	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_nxt);
4663	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_una);
4664	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, window_clamp);
4665	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, srtt_us);
4666	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, packets_out);
4667	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_up);
4668	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, delivered);
4669	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, delivered_ce);
4670	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, app_limited);
4671	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rcv_wnd);
4672	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rx_opt);
4673	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_txrx, 76);
4674
4675	/* RX read-write hotpath cache lines */
4676	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, bytes_received);
4677	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, segs_in);
4678	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, data_segs_in);
4679	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_wup);
4680	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, max_packets_out);
4681	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, cwnd_usage_seq);
4682	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rate_delivered);
4683	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rate_interval_us);
4684	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_rtt_last_tsecr);
4685	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, first_tx_mstamp);
4686	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, delivered_mstamp);
4687	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, bytes_acked);
4688	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_rtt_est);
4689	CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcvq_space);
4690	CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_rx, 99);
4691	}
4692
4693	void __init tcp_init(void)
4694	{
4695	int max_rshare, max_wshare, cnt;
4696	unsigned long limit;
4697	unsigned int i;
4698
4699	BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
4700	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
4701	sizeof_field(struct sk_buff, cb));
4702
4703	tcp_struct_check();
4704
4705	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
4706
4707	timer_setup(&tcp_orphan_timer, tcp_orphan_update, TIMER_DEFERRABLE);
4708	mod_timer(timer: &tcp_orphan_timer, expires: jiffies + TCP_ORPHAN_TIMER_PERIOD);
4709
4710	inet_hashinfo2_init(h: &tcp_hashinfo, name: "tcp_listen_portaddr_hash",
4711	numentries: thash_entries, scale: 21, /* one slot per 2 MB*/
4712	low_limit: 0, high_limit: 64 * 1024);
4713	tcp_hashinfo.bind_bucket_cachep =
4714	kmem_cache_create(name: "tcp_bind_bucket",
4715	size: sizeof(struct inet_bind_bucket), align: 0,
4716	SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4717	SLAB_ACCOUNT,
4718	NULL);
4719	tcp_hashinfo.bind2_bucket_cachep =
4720	kmem_cache_create(name: "tcp_bind2_bucket",
4721	size: sizeof(struct inet_bind2_bucket), align: 0,
4722	SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4723	SLAB_ACCOUNT,
4724	NULL);
4725
4726	/* Size and allocate the main established and bind bucket
4727	* hash tables.
4728	*
4729	* The methodology is similar to that of the buffer cache.
4730	*/
4731	tcp_hashinfo.ehash =
4732	alloc_large_system_hash(tablename: "TCP established",
4733	bucketsize: sizeof(struct inet_ehash_bucket),
4734	numentries: thash_entries,
4735	scale: 17, /* one slot per 128 KB of memory */
4736	flags: 0,
4737	NULL,
4738	hash_mask: &tcp_hashinfo.ehash_mask,
4739	low_limit: 0,
4740	high_limit: thash_entries ? 0 : 512 * 1024);
4741	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
4742	INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
4743
4744	if (inet_ehash_locks_alloc(hashinfo: &tcp_hashinfo))
4745	panic(fmt: "TCP: failed to alloc ehash_locks");
4746	tcp_hashinfo.bhash =
4747	alloc_large_system_hash(tablename: "TCP bind",
4748	bucketsize: 2 * sizeof(struct inet_bind_hashbucket),
4749	numentries: tcp_hashinfo.ehash_mask + 1,
4750	scale: 17, /* one slot per 128 KB of memory */
4751	flags: 0,
4752	hash_shift: &tcp_hashinfo.bhash_size,
4753	NULL,
4754	low_limit: 0,
4755	high_limit: 64 * 1024);
4756	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
4757	tcp_hashinfo.bhash2 = tcp_hashinfo.bhash + tcp_hashinfo.bhash_size;
4758	for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
4759	spin_lock_init(&tcp_hashinfo.bhash[i].lock);
4760	INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
4761	spin_lock_init(&tcp_hashinfo.bhash2[i].lock);
4762	INIT_HLIST_HEAD(&tcp_hashinfo.bhash2[i].chain);
4763	}
4764
4765	tcp_hashinfo.pernet = false;
4766
4767	cnt = tcp_hashinfo.ehash_mask + 1;
4768	sysctl_tcp_max_orphans = cnt / 2;
4769
4770	tcp_init_mem();
4771	/* Set per-socket limits to no more than 1/128 the pressure threshold */
4772	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
4773	max_wshare = min(4UL*1024*1024, limit);
4774	max_rshare = min(6UL*1024*1024, limit);
4775
4776	init_net.ipv4.sysctl_tcp_wmem[0] = PAGE_SIZE;
4777	init_net.ipv4.sysctl_tcp_wmem[1] = 16*1024;
4778	init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
4779
4780	init_net.ipv4.sysctl_tcp_rmem[0] = PAGE_SIZE;
4781	init_net.ipv4.sysctl_tcp_rmem[1] = 131072;
4782	init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare);
4783
4784	pr_info("Hash tables configured (established %u bind %u)\n",
4785	tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
4786
4787	tcp_v4_init();
4788	tcp_metrics_init();
4789	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
4790	tcp_tasklet_init();
4791	mptcp_init();
4792	}
4793