[linux-2.6-block.git] / net / rxrpc / call_event.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/circ_buf.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/udp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

/*
 * Propose a PING ACK be sent.
 */
static void rxrpc_propose_ping(struct rxrpc_call *call,
			       bool immediate, bool background)
{
	if (immediate) {
		if (background &&
		    !test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
			rxrpc_queue_call(call);
	} else {
		unsigned long now = jiffies;
		unsigned long ping_at = now + rxrpc_idle_ack_delay;

		if (time_before(ping_at, call->ping_at)) {
			WRITE_ONCE(call->ping_at, ping_at);
			rxrpc_reduce_call_timer(call, ping_at, now,
						rxrpc_timer_set_for_ping);
		}
	}
}

/*
 * propose an ACK be sent
 */
static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
				u16 skew, u32 serial, bool immediate,
				bool background,
				enum rxrpc_propose_ack_trace why)
{
	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
	unsigned long expiry = rxrpc_soft_ack_delay;
	s8 prior = rxrpc_ack_priority[ack_reason];

	/* Pings are handled specially because we don't want to accidentally
	 * lose a ping response by subsuming it into a ping.
	 */
	if (ack_reason == RXRPC_ACK_PING) {
		rxrpc_propose_ping(call, immediate, background);
		goto trace;
	}

	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	 * numbers, but we don't alter the timeout.
	 */
	_debug("prior %u %u vs %u %u",
	       ack_reason, prior,
	       call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
	if (ack_reason == call->ackr_reason) {
		if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
			outcome = rxrpc_propose_ack_update;
			call->ackr_serial = serial;
			call->ackr_skew = skew;
		}
		if (!immediate)
			goto trace;
	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
		call->ackr_reason = ack_reason;
		call->ackr_serial = serial;
		call->ackr_skew = skew;
	} else {
		outcome = rxrpc_propose_ack_subsume;
	}

	switch (ack_reason) {
	case RXRPC_ACK_REQUESTED:
		if (rxrpc_requested_ack_delay < expiry)
			expiry = rxrpc_requested_ack_delay;
		if (serial == 1)
			immediate = false;
		break;

	case RXRPC_ACK_DELAY:
		if (rxrpc_soft_ack_delay < expiry)
			expiry = rxrpc_soft_ack_delay;
		break;

	case RXRPC_ACK_IDLE:
		if (rxrpc_idle_ack_delay < expiry)
			expiry = rxrpc_idle_ack_delay;
		break;

	default:
		immediate = true;
		break;
	}

	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
		_debug("already scheduled");
	} else if (immediate || expiry == 0) {
		_debug("immediate ACK %lx", call->events);
		if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
		    background)
			rxrpc_queue_call(call);
	} else {
		unsigned long now = jiffies, ack_at;

		if (call->peer->rtt_usage > 0)
			ack_at = nsecs_to_jiffies(call->peer->rtt);
		else
			ack_at = expiry;

		ack_at += READ_ONCE(call->tx_backoff);
		ack_at += now;
		if (time_before(ack_at, call->ack_at)) {
			WRITE_ONCE(call->ack_at, ack_at);
			rxrpc_reduce_call_timer(call, ack_at, now,
						rxrpc_timer_set_for_ack);
		}
	}

trace:
	trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
				background, outcome);
}

/*
 * propose an ACK be sent, locking the call structure
 */
void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
		       u16 skew, u32 serial, bool immediate, bool background,
		       enum rxrpc_propose_ack_trace why)
{
	spin_lock_bh(&call->lock);
	__rxrpc_propose_ACK(call, ack_reason, skew, serial,
			    immediate, background, why);
	spin_unlock_bh(&call->lock);
}

/*
 * Handle congestion being detected by the retransmit timeout.
 */
static void rxrpc_congestion_timeout(struct rxrpc_call *call)
{
	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
}

/*
 * Perform retransmission of NAK'd and unack'd packets.
 */
static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
{
	struct sk_buff *skb;
	unsigned long resend_at;
	rxrpc_seq_t cursor, seq, top;
	ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
	int ix;
	u8 annotation, anno_type, retrans = 0, unacked = 0;

	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);

	if (call->peer->rtt_usage > 1)
		timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
	else
		timeout = ms_to_ktime(rxrpc_resend_timeout);
	min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
	if (ktime_before(timeout, min_timeo))
		timeout = min_timeo;

	now = ktime_get_real();
	max_age = ktime_sub(now, timeout);

	spin_lock_bh(&call->lock);

	cursor = call->tx_hard_ack;
	top = call->tx_top;
	ASSERT(before_eq(cursor, top));
	if (cursor == top)
		goto out_unlock;

	/* Scan the packet list without dropping the lock and decide which of
	 * the packets in the Tx buffer we're going to resend and what the new
	 * resend timeout will be.
	 */
	trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
	oldest = now;
	for (seq = cursor + 1; before_eq(seq, top); seq++) {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		anno_type = annotation & RXRPC_TX_ANNO_MASK;
		annotation &= ~RXRPC_TX_ANNO_MASK;
		if (anno_type == RXRPC_TX_ANNO_ACK)
			continue;

		skb = call->rxtx_buffer[ix];
		rxrpc_see_skb(skb, rxrpc_skb_tx_seen);

		if (anno_type == RXRPC_TX_ANNO_UNACK) {
			if (ktime_after(skb->tstamp, max_age)) {
				if (ktime_before(skb->tstamp, oldest))
					oldest = skb->tstamp;
				continue;
			}
			if (!(annotation & RXRPC_TX_ANNO_RESENT))
				unacked++;
		}

		/* Okay, we need to retransmit a packet. */
		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
		retrans++;
		trace_rxrpc_retransmit(call, seq, annotation | anno_type,
				       ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
	}

	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
	resend_at += jiffies + rxrpc_resend_timeout;
	WRITE_ONCE(call->resend_at, resend_at);

	if (unacked)
		rxrpc_congestion_timeout(call);

	/* If there was nothing that needed retransmission then it's likely
	 * that an ACK got lost somewhere.  Send a ping to find out instead of
	 * retransmitting data.
	 */
	if (!retrans) {
		rxrpc_reduce_call_timer(call, resend_at, now_j,
					rxrpc_timer_set_for_resend);
		spin_unlock_bh(&call->lock);
		ack_ts = ktime_sub(now, call->acks_latest_ts);
		if (ktime_to_ns(ack_ts) < call->peer->rtt)
			goto out;
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
				  rxrpc_propose_ack_ping_for_lost_ack);
		rxrpc_send_ack_packet(call, true, NULL);
		goto out;
	}

	/* Now go through the Tx window and perform the retransmissions.  We
	 * have to drop the lock for each send.  If an ACK comes in whilst the
	 * lock is dropped, it may clear some of the retransmission markers for
	 * packets that it soft-ACKs.
	 */
	for (seq = cursor + 1; before_eq(seq, top); seq++) {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		anno_type = annotation & RXRPC_TX_ANNO_MASK;
		if (anno_type != RXRPC_TX_ANNO_RETRANS)
			continue;

		skb = call->rxtx_buffer[ix];
		rxrpc_get_skb(skb, rxrpc_skb_tx_got);
		spin_unlock_bh(&call->lock);

		if (rxrpc_send_data_packet(call, skb, true) < 0) {
			rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
			return;
		}

		if (rxrpc_is_client_call(call))
			rxrpc_expose_client_call(call);

		rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
		spin_lock_bh(&call->lock);

		/* We need to clear the retransmit state, but there are two
		 * things we need to be aware of: A new ACK/NAK might have been
		 * received and the packet might have been hard-ACK'd (in which
		 * case it will no longer be in the buffer).
		 */
		if (after(seq, call->tx_hard_ack)) {
			annotation = call->rxtx_annotations[ix];
			anno_type = annotation & RXRPC_TX_ANNO_MASK;
			if (anno_type == RXRPC_TX_ANNO_RETRANS ||
			    anno_type == RXRPC_TX_ANNO_NAK) {
				annotation &= ~RXRPC_TX_ANNO_MASK;
				annotation |= RXRPC_TX_ANNO_UNACK;
			}
			annotation |= RXRPC_TX_ANNO_RESENT;
			call->rxtx_annotations[ix] = annotation;
		}

		if (after(call->tx_hard_ack, seq))
			seq = call->tx_hard_ack;
	}

out_unlock:
	spin_unlock_bh(&call->lock);
out:
	_leave("");
}

/*
 * Handle retransmission and deferred ACK/abort generation.
 */
void rxrpc_process_call(struct work_struct *work)
{
	struct rxrpc_call *call =
		container_of(work, struct rxrpc_call, processor);
	rxrpc_serial_t *send_ack;
	unsigned long now, next, t;
	unsigned int iterations = 0;

	rxrpc_see_call(call);

	//printk("\n--------------------\n");
	_enter("{%d,%s,%lx}",
	       call->debug_id, rxrpc_call_states[call->state], call->events);

recheck_state:
	/* Limit the number of times we do this before returning to the manager */
	iterations++;
	if (iterations > 5)
		goto requeue;

	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
		rxrpc_send_abort_packet(call);
		goto recheck_state;
	}

	if (call->state == RXRPC_CALL_COMPLETE) {
		del_timer_sync(&call->timer);
		rxrpc_notify_socket(call);
		goto out_put;
	}

	/* Work out if any timeouts tripped */
	now = jiffies;
	t = READ_ONCE(call->expect_rx_by);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->expect_req_by);
	if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
	    time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->expect_term_by);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->ack_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
		cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_ACK, &call->events);
	}

	t = READ_ONCE(call->ack_lost_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
		cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
	}

	t = READ_ONCE(call->keepalive_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
		cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, true,
				  rxrpc_propose_ack_ping_for_keepalive);
		set_bit(RXRPC_CALL_EV_PING, &call->events);
	}

	t = READ_ONCE(call->ping_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
		cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_PING, &call->events);
	}

	t = READ_ONCE(call->resend_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
		cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_RESEND, &call->events);
	}

	/* Process events */
	if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
		if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
		    (int)call->conn->hi_serial - (int)call->rx_serial > 0) {
			trace_rxrpc_call_reset(call);
			rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ECONNRESET);
		} else {
			rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
		}
		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
		goto recheck_state;
	}

	send_ack = NULL;
	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
		call->acks_lost_top = call->tx_top;
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
				  rxrpc_propose_ack_ping_for_lost_ack);
		send_ack = &call->acks_lost_ping;
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
	    send_ack) {
		if (call->ackr_reason) {
			rxrpc_send_ack_packet(call, false, send_ack);
			goto recheck_state;
		}
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
		rxrpc_send_ack_packet(call, true, NULL);
		goto recheck_state;
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
		rxrpc_resend(call, now);
		goto recheck_state;
	}

	/* Make sure the timer is restarted */
	next = call->expect_rx_by;

#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }

	set(call->expect_req_by);
	set(call->expect_term_by);
	set(call->ack_at);
	set(call->ack_lost_at);
	set(call->resend_at);
	set(call->keepalive_at);
	set(call->ping_at);

	now = jiffies;
	if (time_after_eq(now, next))
		goto recheck_state;

	rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);

	/* other events may have been raised since we started checking */
	if (call->events && call->state < RXRPC_CALL_COMPLETE)
		goto requeue;

out_put:
	rxrpc_put_call(call, rxrpc_call_put);
out:
	_leave("");
	return;

requeue:
	__rxrpc_queue_call(call);
	goto out;
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
17926a79 DH	2	/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
	3	*
	4	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
17926a79 DH	6	*/
17926a79 DH	7
9b6d5398 JP	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	9
17926a79 DH	10	#include <linux/module.h>
	11	#include <linux/circ_buf.h>
	12	#include <linux/net.h>
	13	#include <linux/skbuff.h>
5a0e3ad6	14	#include <linux/slab.h>
17926a79 DH	15	#include <linux/udp.h>
	16	#include <net/sock.h>
	17	#include <net/af_rxrpc.h>
	18	#include "ar-internal.h"
	19
a5af7e1f DH	20	/*
	21	* Propose a PING ACK be sent.
	22	*/
	23	static void rxrpc_propose_ping(struct rxrpc_call *call,
	24	bool immediate, bool background)
	25	{
	26	if (immediate) {
	27	if (background &&
	28	!test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
	29	rxrpc_queue_call(call);
	30	} else {
a158bdd3 DH	31	unsigned long now = jiffies;
a158bdd3 DH	32	unsigned long ping_at = now + rxrpc_idle_ack_delay;
a5af7e1f	33
a158bdd3 DH	34	if (time_before(ping_at, call->ping_at)) {
	35	WRITE_ONCE(call->ping_at, ping_at);
	36	rxrpc_reduce_call_timer(call, ping_at, now,
	37	rxrpc_timer_set_for_ping);
a5af7e1f DH	38	}
	39	}
	40	}
	41
17926a79	42	/*
248f219c	43	* propose an ACK be sent
17926a79	44	*/
248f219c DH	45	static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
248f219c DH	46	u16 skew, u32 serial, bool immediate,
9c7ad434 DH	47	bool background,
9c7ad434 DH	48	enum rxrpc_propose_ack_trace why)
17926a79	49	{
9c7ad434	50	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
beb8e5e4	51	unsigned long expiry = rxrpc_soft_ack_delay;
17926a79 DH	52	s8 prior = rxrpc_ack_priority[ack_reason];
17926a79 DH	53
a5af7e1f DH	54	/* Pings are handled specially because we don't want to accidentally
	55	* lose a ping response by subsuming it into a ping.
	56	*/
	57	if (ack_reason == RXRPC_ACK_PING) {
	58	rxrpc_propose_ping(call, immediate, background);
	59	goto trace;
	60	}
	61
248f219c DH	62	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	63	* numbers, but we don't alter the timeout.
	64	*/
	65	_debug("prior %u %u vs %u %u",
	66	ack_reason, prior,
	67	call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
	68	if (ack_reason == call->ackr_reason) {
	69	if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
9c7ad434	70	outcome = rxrpc_propose_ack_update;
248f219c DH	71	call->ackr_serial = serial;
248f219c DH	72	call->ackr_skew = skew;
17926a79	73	}
248f219c	74	if (!immediate)
9c7ad434	75	goto trace;
248f219c DH	76	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
	77	call->ackr_reason = ack_reason;
	78	call->ackr_serial = serial;
	79	call->ackr_skew = skew;
9c7ad434 DH	80	} else {
9c7ad434 DH	81	outcome = rxrpc_propose_ack_subsume;
17926a79 DH	82	}
17926a79 DH	83
248f219c DH	84	switch (ack_reason) {
	85	case RXRPC_ACK_REQUESTED:
	86	if (rxrpc_requested_ack_delay < expiry)
	87	expiry = rxrpc_requested_ack_delay;
	88	if (serial == 1)
	89	immediate = false;
	90	break;
17926a79	91
248f219c DH	92	case RXRPC_ACK_DELAY:
	93	if (rxrpc_soft_ack_delay < expiry)
	94	expiry = rxrpc_soft_ack_delay;
	95	break;
17926a79	96
248f219c	97	case RXRPC_ACK_IDLE:
91c2c7b6	98	if (rxrpc_idle_ack_delay < expiry)
248f219c DH	99	expiry = rxrpc_idle_ack_delay;
248f219c DH	100	break;
17926a79	101
248f219c DH	102	default:
	103	immediate = true;
	104	break;
17926a79 DH	105	}
17926a79 DH	106
248f219c DH	107	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
	108	_debug("already scheduled");
	109	} else if (immediate \|\| expiry == 0) {
	110	_debug("immediate ACK %lx", call->events);
	111	if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
	112	background)
	113	rxrpc_queue_call(call);
	114	} else {
beb8e5e4 DH	115	unsigned long now = jiffies, ack_at;
	116
	117	if (call->peer->rtt_usage > 0)
	118	ack_at = nsecs_to_jiffies(call->peer->rtt);
	119	else
	120	ack_at = expiry;
	121
c7e86acf	122	ack_at += READ_ONCE(call->tx_backoff);
282ef472	123	ack_at += now;
a158bdd3 DH	124	if (time_before(ack_at, call->ack_at)) {
	125	WRITE_ONCE(call->ack_at, ack_at);
	126	rxrpc_reduce_call_timer(call, ack_at, now,
	127	rxrpc_timer_set_for_ack);
17926a79 DH	128	}
17926a79 DH	129	}
9c7ad434 DH	130
	131	trace:
	132	trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
	133	background, outcome);
17926a79 DH	134	}
	135
	136	/*
248f219c	137	* propose an ACK be sent, locking the call structure
17926a79	138	*/
248f219c	139	void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
9c7ad434 DH	140	u16 skew, u32 serial, bool immediate, bool background,
9c7ad434 DH	141	enum rxrpc_propose_ack_trace why)
17926a79	142	{
248f219c DH	143	spin_lock_bh(&call->lock);
248f219c DH	144	__rxrpc_propose_ACK(call, ack_reason, skew, serial,
9c7ad434	145	immediate, background, why);
248f219c	146	spin_unlock_bh(&call->lock);
17926a79 DH	147	}
17926a79 DH	148
57494343 DH	149	/*
	150	* Handle congestion being detected by the retransmit timeout.
	151	*/
	152	static void rxrpc_congestion_timeout(struct rxrpc_call *call)
	153	{
	154	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
	155	}
	156
17926a79	157	/*
248f219c	158	* Perform retransmission of NAK'd and unack'd packets.
17926a79	159	*/
a158bdd3	160	static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
17926a79	161	{
17926a79	162	struct sk_buff *skb;
a158bdd3	163	unsigned long resend_at;
248f219c	164	rxrpc_seq_t cursor, seq, top;
beb8e5e4	165	ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
248f219c	166	int ix;
57494343	167	u8 annotation, anno_type, retrans = 0, unacked = 0;
17926a79	168
248f219c	169	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
17926a79	170
beb8e5e4 DH	171	if (call->peer->rtt_usage > 1)
	172	timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
	173	else
	174	timeout = ms_to_ktime(rxrpc_resend_timeout);
	175	min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
	176	if (ktime_before(timeout, min_timeo))
	177	timeout = min_timeo;
	178
a158bdd3	179	now = ktime_get_real();
beb8e5e4	180	max_age = ktime_sub(now, timeout);
50235c4b	181
17926a79 DH	182	spin_lock_bh(&call->lock);
17926a79 DH	183
248f219c DH	184	cursor = call->tx_hard_ack;
	185	top = call->tx_top;
	186	ASSERT(before_eq(cursor, top));
	187	if (cursor == top)
	188	goto out_unlock;
	189
	190	/* Scan the packet list without dropping the lock and decide which of
	191	* the packets in the Tx buffer we're going to resend and what the new
	192	* resend timeout will be.
	193	*/
827efed6	194	trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
50235c4b	195	oldest = now;
dfa7d920	196	for (seq = cursor + 1; before_eq(seq, top); seq++) {
248f219c DH	197	ix = seq & RXRPC_RXTX_BUFF_MASK;
248f219c DH	198	annotation = call->rxtx_annotations[ix];
f07373ea DH	199	anno_type = annotation & RXRPC_TX_ANNO_MASK;
	200	annotation &= ~RXRPC_TX_ANNO_MASK;
	201	if (anno_type == RXRPC_TX_ANNO_ACK)
248f219c	202	continue;
17926a79	203
248f219c	204	skb = call->rxtx_buffer[ix];
71f3ca40	205	rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
17926a79	206
f07373ea	207	if (anno_type == RXRPC_TX_ANNO_UNACK) {
50235c4b DH	208	if (ktime_after(skb->tstamp, max_age)) {
	209	if (ktime_before(skb->tstamp, oldest))
	210	oldest = skb->tstamp;
248f219c	211	continue;
33c40e24	212	}
57494343 DH	213	if (!(annotation & RXRPC_TX_ANNO_RESENT))
57494343 DH	214	unacked++;
17926a79	215	}
17926a79	216
248f219c	217	/* Okay, we need to retransmit a packet. */
f07373ea	218	call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS \| annotation;
57494343	219	retrans++;
c6672e3f DH	220	trace_rxrpc_retransmit(call, seq, annotation \| anno_type,
c6672e3f DH	221	ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
dfa7d920	222	}
248f219c	223
59299aa1	224	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
a158bdd3 DH	225	resend_at += jiffies + rxrpc_resend_timeout;
a158bdd3 DH	226	WRITE_ONCE(call->resend_at, resend_at);
248f219c	227
57494343 DH	228	if (unacked)
	229	rxrpc_congestion_timeout(call);
	230
	231	/* If there was nothing that needed retransmission then it's likely
	232	* that an ACK got lost somewhere. Send a ping to find out instead of
	233	* retransmitting data.
	234	*/
	235	if (!retrans) {
f82eb88b	236	rxrpc_reduce_call_timer(call, resend_at, now_j,
a158bdd3	237	rxrpc_timer_set_for_resend);
57494343 DH	238	spin_unlock_bh(&call->lock);
	239	ack_ts = ktime_sub(now, call->acks_latest_ts);
	240	if (ktime_to_ns(ack_ts) < call->peer->rtt)
	241	goto out;
	242	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
	243	rxrpc_propose_ack_ping_for_lost_ack);
bd1fdf8c	244	rxrpc_send_ack_packet(call, true, NULL);
57494343 DH	245	goto out;
	246	}
	247
248f219c DH	248	/* Now go through the Tx window and perform the retransmissions. We
	249	* have to drop the lock for each send. If an ACK comes in whilst the
	250	* lock is dropped, it may clear some of the retransmission markers for
	251	* packets that it soft-ACKs.
	252	*/
dfa7d920	253	for (seq = cursor + 1; before_eq(seq, top); seq++) {
248f219c DH	254	ix = seq & RXRPC_RXTX_BUFF_MASK;
248f219c DH	255	annotation = call->rxtx_annotations[ix];
f07373ea DH	256	anno_type = annotation & RXRPC_TX_ANNO_MASK;
f07373ea DH	257	if (anno_type != RXRPC_TX_ANNO_RETRANS)
248f219c	258	continue;
17926a79	259
248f219c	260	skb = call->rxtx_buffer[ix];
71f3ca40	261	rxrpc_get_skb(skb, rxrpc_skb_tx_got);
17926a79	262	spin_unlock_bh(&call->lock);
17926a79	263
a1767077	264	if (rxrpc_send_data_packet(call, skb, true) < 0) {
71f3ca40	265	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
248f219c DH	266	return;
248f219c DH	267	}
17926a79	268
248f219c DH	269	if (rxrpc_is_client_call(call))
248f219c DH	270	rxrpc_expose_client_call(call);
17926a79	271
71f3ca40	272	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
17926a79	273	spin_lock_bh(&call->lock);
17926a79	274
248f219c DH	275	/* We need to clear the retransmit state, but there are two
	276	* things we need to be aware of: A new ACK/NAK might have been
	277	* received and the packet might have been hard-ACK'd (in which
	278	* case it will no longer be in the buffer).
	279	*/
f07373ea DH	280	if (after(seq, call->tx_hard_ack)) {
	281	annotation = call->rxtx_annotations[ix];
	282	anno_type = annotation & RXRPC_TX_ANNO_MASK;
	283	if (anno_type == RXRPC_TX_ANNO_RETRANS \|\|
	284	anno_type == RXRPC_TX_ANNO_NAK) {
	285	annotation &= ~RXRPC_TX_ANNO_MASK;
	286	annotation \|= RXRPC_TX_ANNO_UNACK;
	287	}
	288	annotation \|= RXRPC_TX_ANNO_RESENT;
	289	call->rxtx_annotations[ix] = annotation;
	290	}
248f219c DH	291
	292	if (after(call->tx_hard_ack, seq))
	293	seq = call->tx_hard_ack;
dfa7d920	294	}
248f219c DH	295
	296	out_unlock:
	297	spin_unlock_bh(&call->lock);
57494343	298	out:
248f219c	299	_leave("");
17926a79 DH	300	}
	301
	302	/*
248f219c	303	* Handle retransmission and deferred ACK/abort generation.
17926a79 DH	304	*/
	305	void rxrpc_process_call(struct work_struct *work)
	306	{
	307	struct rxrpc_call *call =
	308	container_of(work, struct rxrpc_call, processor);
bd1fdf8c	309	rxrpc_serial_t *send_ack;
a158bdd3	310	unsigned long now, next, t;
c7e86acf	311	unsigned int iterations = 0;
17926a79	312
e34d4234 DH	313	rxrpc_see_call(call);
e34d4234 DH	314
17926a79	315	//printk("\n--------------------\n");
248f219c DH	316	_enter("{%d,%s,%lx}",
248f219c DH	317	call->debug_id, rxrpc_call_states[call->state], call->events);
17926a79	318
248f219c	319	recheck_state:
c7e86acf DH	320	/* Limit the number of times we do this before returning to the manager */
	321	iterations++;
	322	if (iterations > 5)
	323	goto requeue;
	324
248f219c	325	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
26cb02aa	326	rxrpc_send_abort_packet(call);
248f219c	327	goto recheck_state;
17926a79 DH	328	}
17926a79 DH	329
248f219c DH	330	if (call->state == RXRPC_CALL_COMPLETE) {
248f219c DH	331	del_timer_sync(&call->timer);
94bc669e	332	rxrpc_notify_socket(call);
248f219c	333	goto out_put;
17926a79 DH	334	}
17926a79 DH	335
a158bdd3 DH	336	/* Work out if any timeouts tripped */
	337	now = jiffies;
	338	t = READ_ONCE(call->expect_rx_by);
	339	if (time_after_eq(now, t)) {
	340	trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
	341	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	342	}
	343
	344	t = READ_ONCE(call->expect_req_by);
	345	if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
	346	time_after_eq(now, t)) {
	347	trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
	348	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	349	}
	350
	351	t = READ_ONCE(call->expect_term_by);
	352	if (time_after_eq(now, t)) {
	353	trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
	354	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	355	}
	356
	357	t = READ_ONCE(call->ack_at);
	358	if (time_after_eq(now, t)) {
	359	trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
	360	cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
	361	set_bit(RXRPC_CALL_EV_ACK, &call->events);
	362	}
	363
bd1fdf8c DH	364	t = READ_ONCE(call->ack_lost_at);
	365	if (time_after_eq(now, t)) {
	366	trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
	367	cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
	368	set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
	369	}
	370
415f44e4 DH	371	t = READ_ONCE(call->keepalive_at);
	372	if (time_after_eq(now, t)) {
	373	trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
	374	cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
	375	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, true,
	376	rxrpc_propose_ack_ping_for_keepalive);
	377	set_bit(RXRPC_CALL_EV_PING, &call->events);
	378	}
	379
a158bdd3 DH	380	t = READ_ONCE(call->ping_at);
	381	if (time_after_eq(now, t)) {
	382	trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
	383	cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
	384	set_bit(RXRPC_CALL_EV_PING, &call->events);
	385	}
	386
	387	t = READ_ONCE(call->resend_at);
	388	if (time_after_eq(now, t)) {
	389	trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
	390	cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
	391	set_bit(RXRPC_CALL_EV_RESEND, &call->events);
	392	}
	393
	394	/* Process events */
	395	if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
1a025028 DH	396	if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
	397	(int)call->conn->hi_serial - (int)call->rx_serial > 0) {
	398	trace_rxrpc_call_reset(call);
	399	rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ECONNRESET);
	400	} else {
	401	rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
	402	}
248f219c	403	set_bit(RXRPC_CALL_EV_ABORT, &call->events);
57494343	404	goto recheck_state;
17926a79 DH	405	}
17926a79 DH	406
bd1fdf8c DH	407	send_ack = NULL;
	408	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
	409	call->acks_lost_top = call->tx_top;
	410	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
	411	rxrpc_propose_ack_ping_for_lost_ack);
	412	send_ack = &call->acks_lost_ping;
	413	}
	414
	415	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) \|\|
	416	send_ack) {
248f219c	417	if (call->ackr_reason) {
bd1fdf8c	418	rxrpc_send_ack_packet(call, false, send_ack);
248f219c	419	goto recheck_state;
17926a79 DH	420	}
	421	}
	422
a5af7e1f	423	if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
bd1fdf8c	424	rxrpc_send_ack_packet(call, true, NULL);
a5af7e1f DH	425	goto recheck_state;
	426	}
	427
405dea1d	428	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
df0adc78	429	rxrpc_resend(call, now);
248f219c	430	goto recheck_state;
17926a79 DH	431	}
17926a79 DH	432
a158bdd3 DH	433	/* Make sure the timer is restarted */
	434	next = call->expect_rx_by;
	435
	436	#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
3d7682af	437
a158bdd3 DH	438	set(call->expect_req_by);
	439	set(call->expect_term_by);
	440	set(call->ack_at);
bd1fdf8c	441	set(call->ack_lost_at);
a158bdd3	442	set(call->resend_at);
415f44e4	443	set(call->keepalive_at);
a158bdd3 DH	444	set(call->ping_at);
	445
	446	now = jiffies;
	447	if (time_after_eq(now, next))
	448	goto recheck_state;
	449
	450	rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
17926a79 DH	451
17926a79 DH	452	/* other events may have been raised since we started checking */
c7e86acf DH	453	if (call->events && call->state < RXRPC_CALL_COMPLETE)
c7e86acf DH	454	goto requeue;
17926a79	455
248f219c DH	456	out_put:
	457	rxrpc_put_call(call, rxrpc_call_put);
	458	out:
17926a79	459	_leave("");
c7e86acf DH	460	return;
	461
	462	requeue:
	463	__rxrpc_queue_call(call);
	464	goto out;
17926a79	465	}