[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.
 */
void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial,
			enum rxrpc_propose_ack_trace why)
{
	unsigned long now = jiffies;
	unsigned long ping_at = now + rxrpc_idle_ack_delay;

	if (time_before(ping_at, call->ping_at)) {
		call->ping_at = ping_at;
		rxrpc_reduce_call_timer(call, ping_at, now,
					rxrpc_timer_set_for_ping);
		trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
	}
}

/*
 * Propose a DELAY ACK be sent in the future.
 */
void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t serial,
			     enum rxrpc_propose_ack_trace why)
{
	unsigned long expiry = rxrpc_soft_ack_delay;
	unsigned long now = jiffies, ack_at;

	if (rxrpc_soft_ack_delay < expiry)
		expiry = rxrpc_soft_ack_delay;
	if (call->peer->srtt_us != 0)
		ack_at = usecs_to_jiffies(call->peer->srtt_us >> 3);
	else
		ack_at = expiry;

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

	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);
}

/*
 * 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.
 */
void rxrpc_resend(struct rxrpc_call *call, struct sk_buff *ack_skb)
{
	struct rxrpc_ackpacket *ack = NULL;
	struct rxrpc_skb_priv *sp;
	struct rxrpc_txbuf *txb;
	unsigned long resend_at;
	rxrpc_seq_t transmitted = call->tx_transmitted;
	ktime_t now, max_age, oldest, ack_ts;
	bool unacked = false;
	unsigned int i;
	LIST_HEAD(retrans_queue);

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

	now = ktime_get_real();
	max_age = ktime_sub_us(now, jiffies_to_usecs(call->peer->rto_j));
	oldest = now;

	if (list_empty(&call->tx_buffer))
		goto no_resend;

	if (list_empty(&call->tx_buffer))
		goto no_further_resend;

	trace_rxrpc_resend(call, ack_skb);
	txb = list_first_entry(&call->tx_buffer, struct rxrpc_txbuf, call_link);

	/* Scan the soft ACK table without dropping the lock and resend any
	 * explicitly NAK'd packets.
	 */
	if (ack_skb) {
		sp = rxrpc_skb(ack_skb);
		ack = (void *)ack_skb->data + sizeof(struct rxrpc_wire_header);

		for (i = 0; i < sp->nr_acks; i++) {
			rxrpc_seq_t seq;

			if (ack->acks[i] & 1)
				continue;
			seq = sp->first_ack + i;
			if (after(txb->seq, transmitted))
				break;
			if (after(txb->seq, seq))
				continue; /* A new hard ACK probably came in */
			list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
				if (txb->seq == seq)
					goto found_txb;
			}
			goto no_further_resend;

		found_txb:
			if (after(txb->serial, call->acks_highest_serial))
				continue; /* Ack point not yet reached */

			rxrpc_see_txbuf(txb, rxrpc_txbuf_see_unacked);

			if (list_empty(&txb->tx_link)) {
				list_add_tail(&txb->tx_link, &retrans_queue);
				txb->flags |= RXRPC_TXBUF_RESENT;
			}

			trace_rxrpc_retransmit(call, txb->seq, txb->serial,
					       ktime_to_ns(ktime_sub(txb->last_sent,
								     max_age)));

			if (list_is_last(&txb->call_link, &call->tx_buffer))
				goto no_further_resend;
			txb = list_next_entry(txb, call_link);
		}
	}

	/* Fast-forward through the Tx queue to the point the peer says it has
	 * seen.  Anything between the soft-ACK table and that point will get
	 * ACK'd or NACK'd in due course, so don't worry about it here; here we
	 * need to consider retransmitting anything beyond that point.
	 */
	if (after_eq(call->acks_prev_seq, call->tx_transmitted))
		goto no_further_resend;

	list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
		if (before_eq(txb->seq, call->acks_prev_seq))
			continue;
		if (after(txb->seq, call->tx_transmitted))
			break; /* Not transmitted yet */

		if (ack && ack->reason == RXRPC_ACK_PING_RESPONSE &&
		    before(txb->serial, ntohl(ack->serial)))
			goto do_resend; /* Wasn't accounted for by a more recent ping. */

		if (ktime_after(txb->last_sent, max_age)) {
			if (ktime_before(txb->last_sent, oldest))
				oldest = txb->last_sent;
			continue;
		}

	do_resend:
		unacked = true;
		if (list_empty(&txb->tx_link)) {
			list_add_tail(&txb->tx_link, &retrans_queue);
			txb->flags |= RXRPC_TXBUF_RESENT;
			rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);
		}
	}

no_further_resend:
no_resend:
	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
	resend_at += jiffies + rxrpc_get_rto_backoff(call->peer,
						     !list_empty(&retrans_queue));
	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 (list_empty(&retrans_queue)) {
		rxrpc_reduce_call_timer(call, resend_at, jiffies,
					rxrpc_timer_set_for_resend);
		ack_ts = ktime_sub(now, call->acks_latest_ts);
		if (ktime_to_us(ack_ts) < (call->peer->srtt_us >> 3))
			goto out;
		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
			       rxrpc_propose_ack_ping_for_lost_ack);
		goto out;
	}

	/* Retransmit the queue */
	while ((txb = list_first_entry_or_null(&retrans_queue,
					       struct rxrpc_txbuf, tx_link))) {
		list_del_init(&txb->tx_link);
		rxrpc_transmit_one(call, txb);
	}

out:
	_leave("");
}

/*
 * Start transmitting the reply to a service.  This cancels the need to ACK the
 * request if we haven't yet done so.
 */
static void rxrpc_begin_service_reply(struct rxrpc_call *call)
{
	unsigned long now = jiffies;

	rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
	call->delay_ack_at = now + MAX_JIFFY_OFFSET;
	if (call->ackr_reason == RXRPC_ACK_DELAY)
		call->ackr_reason = 0;
	trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
}

/*
 * Close the transmission phase.  After this point there is no more data to be
 * transmitted in the call.
 */
static void rxrpc_close_tx_phase(struct rxrpc_call *call)
{
	_debug("________awaiting reply/ACK__________");

	switch (__rxrpc_call_state(call)) {
	case RXRPC_CALL_CLIENT_SEND_REQUEST:
		rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY);
		break;
	case RXRPC_CALL_SERVER_SEND_REPLY:
		rxrpc_set_call_state(call, RXRPC_CALL_SERVER_AWAIT_ACK);
		break;
	default:
		break;
	}
}

static bool rxrpc_tx_window_has_space(struct rxrpc_call *call)
{
	unsigned int winsize = min_t(unsigned int, call->tx_winsize,
				     call->cong_cwnd + call->cong_extra);
	rxrpc_seq_t window = call->acks_hard_ack, wtop = window + winsize;
	rxrpc_seq_t tx_top = call->tx_top;
	int space;

	space = wtop - tx_top;
	return space > 0;
}

/*
 * Decant some if the sendmsg prepared queue into the transmission buffer.
 */
static void rxrpc_decant_prepared_tx(struct rxrpc_call *call)
{
	struct rxrpc_txbuf *txb;

	if (!test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
		if (list_empty(&call->tx_sendmsg))
			return;
		rxrpc_expose_client_call(call);
	}

	while ((txb = list_first_entry_or_null(&call->tx_sendmsg,
					       struct rxrpc_txbuf, call_link))) {
		spin_lock(&call->tx_lock);
		list_del(&txb->call_link);
		spin_unlock(&call->tx_lock);

		call->tx_top = txb->seq;
		list_add_tail(&txb->call_link, &call->tx_buffer);

		if (txb->flags & RXRPC_LAST_PACKET)
			rxrpc_close_tx_phase(call);

		rxrpc_transmit_one(call, txb);

		if (!rxrpc_tx_window_has_space(call))
			break;
	}
}

static void rxrpc_transmit_some_data(struct rxrpc_call *call)
{
	switch (__rxrpc_call_state(call)) {
	case RXRPC_CALL_SERVER_ACK_REQUEST:
		if (list_empty(&call->tx_sendmsg))
			return;
		rxrpc_begin_service_reply(call);
		fallthrough;

	case RXRPC_CALL_SERVER_SEND_REPLY:
	case RXRPC_CALL_CLIENT_SEND_REQUEST:
		if (!rxrpc_tx_window_has_space(call))
			return;
		if (list_empty(&call->tx_sendmsg)) {
			rxrpc_inc_stat(call->rxnet, stat_tx_data_underflow);
			return;
		}
		rxrpc_decant_prepared_tx(call);
		break;
	default:
		return;
	}
}

/*
 * Ping the other end to fill our RTT cache and to retrieve the rwind
 * and MTU parameters.
 */
static void rxrpc_send_initial_ping(struct rxrpc_call *call)
{
	if (call->peer->rtt_count < 3 ||
	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
			 ktime_get_real()))
		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
			       rxrpc_propose_ack_ping_for_params);
}

/*
 * Handle retransmission and deferred ACK/abort generation.
 */
bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
{
	unsigned long now, next, t;
	bool resend = false, expired = false;
	s32 abort_code;

	rxrpc_see_call(call, rxrpc_call_see_input);

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

	if (__rxrpc_call_is_complete(call))
		goto out;

	/* Handle abort request locklessly, vs rxrpc_propose_abort(). */
	abort_code = smp_load_acquire(&call->send_abort);
	if (abort_code) {
		rxrpc_abort_call(call, 0, call->send_abort, call->send_abort_err,
				 call->send_abort_why);
		goto out;
	}

	if (skb && skb->mark == RXRPC_SKB_MARK_ERROR)
		goto out;

	/* If we see our async-event poke, check for timeout trippage. */
	now = jiffies;
	t = call->expect_rx_by;
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
		expired = true;
	}

	t = call->expect_req_by;
	if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST &&
	    time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
		expired = true;
	}

	t = READ_ONCE(call->expect_term_by);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
		expired = true;
	}

	t = call->delay_ack_at;
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
		call->delay_ack_at = now + MAX_JIFFY_OFFSET;
		rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
			       rxrpc_propose_ack_ping_for_lost_ack);
	}

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

	t = call->keepalive_at;
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
		call->keepalive_at = now + MAX_JIFFY_OFFSET;
		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
			       rxrpc_propose_ack_ping_for_keepalive);
	}

	t = call->ping_at;
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
		call->ping_at = now + MAX_JIFFY_OFFSET;
		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
			       rxrpc_propose_ack_ping_for_keepalive);
	}

	t = call->resend_at;
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
		call->resend_at = now + MAX_JIFFY_OFFSET;
		resend = true;
	}

	if (skb)
		rxrpc_input_call_packet(call, skb);

	rxrpc_transmit_some_data(call);

	if (skb) {
		struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

		if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK)
			rxrpc_congestion_degrade(call);
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events))
		rxrpc_send_initial_ping(call);

	/* Process events */
	if (expired) {
		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(call, 0, RX_CALL_DEAD, -ECONNRESET,
					 rxrpc_abort_call_reset);
		} else {
			rxrpc_abort_call(call, 0, RX_CALL_TIMEOUT, -ETIME,
					 rxrpc_abort_call_timeout);
		}
		goto out;
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
			       rxrpc_propose_ack_ping_for_lost_ack);

	if (resend && __rxrpc_call_state(call) != RXRPC_CALL_CLIENT_RECV_REPLY)
		rxrpc_resend(call, NULL);

	if (test_and_clear_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
		rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
			       rxrpc_propose_ack_rx_idle);

	if (call->ackr_nr_unacked > 2) {
		if (call->peer->rtt_count < 3)
			rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
				       rxrpc_propose_ack_ping_for_rtt);
		else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
				      ktime_get_real()))
			rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
				       rxrpc_propose_ack_ping_for_old_rtt);
		else
			rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
				       rxrpc_propose_ack_input_data);
	}

	/* Make sure the timer is restarted */
	if (!__rxrpc_call_is_complete(call)) {
		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->delay_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))
			rxrpc_poke_call(call, rxrpc_call_poke_timer_now);

		rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
	}

out:
	if (__rxrpc_call_is_complete(call)) {
		del_timer_sync(&call->timer);
		if (!test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
			rxrpc_disconnect_call(call);
		if (call->security)
			call->security->free_call_crypto(call);
	}
	if (call->acks_hard_ack != call->tx_bottom)
		rxrpc_shrink_call_tx_buffer(call);
	_leave("");
	return true;
}
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	*/
72f0c6fb DH	23	void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial,
72f0c6fb DH	24	enum rxrpc_propose_ack_trace why)
a5af7e1f	25	{
72f0c6fb DH	26	unsigned long now = jiffies;
72f0c6fb DH	27	unsigned long ping_at = now + rxrpc_idle_ack_delay;
a5af7e1f	28
72f0c6fb	29	if (time_before(ping_at, call->ping_at)) {
d73f3a74	30	call->ping_at = ping_at;
72f0c6fb DH	31	rxrpc_reduce_call_timer(call, ping_at, now,
72f0c6fb DH	32	rxrpc_timer_set_for_ping);
530403d9	33	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
a5af7e1f DH	34	}
	35	}
	36
17926a79	37	/*
530403d9	38	* Propose a DELAY ACK be sent in the future.
17926a79	39	*/
4e76bd40 DH	40	void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t serial,
4e76bd40 DH	41	enum rxrpc_propose_ack_trace why)
17926a79	42	{
beb8e5e4	43	unsigned long expiry = rxrpc_soft_ack_delay;
72f0c6fb	44	unsigned long now = jiffies, ack_at;
17926a79	45
530403d9 DH	46	if (rxrpc_soft_ack_delay < expiry)
530403d9 DH	47	expiry = rxrpc_soft_ack_delay;
72f0c6fb DH	48	if (call->peer->srtt_us != 0)
	49	ack_at = usecs_to_jiffies(call->peer->srtt_us >> 3);
	50	else
	51	ack_at = expiry;
	52
	53	ack_at += READ_ONCE(call->tx_backoff);
	54	ack_at += now;
530403d9	55	if (time_before(ack_at, call->delay_ack_at)) {
d73f3a74	56	call->delay_ack_at = ack_at;
72f0c6fb DH	57	rxrpc_reduce_call_timer(call, ack_at, now,
72f0c6fb DH	58	rxrpc_timer_set_for_ack);
17926a79	59	}
9c7ad434	60
530403d9	61	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);
17926a79 DH	62	}
17926a79 DH	63
57494343 DH	64	/*
	65	* Handle congestion being detected by the retransmit timeout.
	66	*/
	67	static void rxrpc_congestion_timeout(struct rxrpc_call *call)
	68	{
	69	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
	70	}
	71
17926a79	72	/*
248f219c	73	* Perform retransmission of NAK'd and unack'd packets.
17926a79	74	*/
5e6ef4f1	75	void rxrpc_resend(struct rxrpc_call call, struct sk_buff ack_skb)
17926a79	76	{
d57a3a15	77	struct rxrpc_ackpacket *ack = NULL;
41b7fa15	78	struct rxrpc_skb_priv *sp;
a4ea4c47	79	struct rxrpc_txbuf *txb;
2c13c05c	80	unsigned long resend_at;
693f9c13	81	rxrpc_seq_t transmitted = call->tx_transmitted;
c410bf01	82	ktime_t now, max_age, oldest, ack_ts;
a4ea4c47	83	bool unacked = false;
d57a3a15	84	unsigned int i;
a4ea4c47	85	LIST_HEAD(retrans_queue);
17926a79	86
a4ea4c47	87	_enter("{%d,%d}", call->acks_hard_ack, call->tx_top);
17926a79	88
a158bdd3	89	now = ktime_get_real();
214a9dc7	90	max_age = ktime_sub_us(now, jiffies_to_usecs(call->peer->rto_j));
d57a3a15 DH	91	oldest = now;
d57a3a15 DH	92
d57a3a15 DH	93	if (list_empty(&call->tx_buffer))
d57a3a15 DH	94	goto no_resend;
50235c4b	95
d57a3a15 DH	96	if (list_empty(&call->tx_buffer))
	97	goto no_further_resend;
	98
5e6ef4f1	99	trace_rxrpc_resend(call, ack_skb);
d57a3a15	100	txb = list_first_entry(&call->tx_buffer, struct rxrpc_txbuf, call_link);
17926a79	101
d57a3a15 DH	102	/* Scan the soft ACK table without dropping the lock and resend any
	103	* explicitly NAK'd packets.
	104	*/
5e6ef4f1	105	if (ack_skb) {
41b7fa15	106	sp = rxrpc_skb(ack_skb);
5e6ef4f1 DH	107	ack = (void *)ack_skb->data + sizeof(struct rxrpc_wire_header);
5e6ef4f1 DH	108
41b7fa15	109	for (i = 0; i < sp->nr_acks; i++) {
d57a3a15	110	rxrpc_seq_t seq;
17926a79	111
d57a3a15	112	if (ack->acks[i] & 1)
248f219c	113	continue;
41b7fa15	114	seq = sp->first_ack + i;
d57a3a15 DH	115	if (after(txb->seq, transmitted))
	116	break;
	117	if (after(txb->seq, seq))
	118	continue; /* A new hard ACK probably came in */
	119	list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
	120	if (txb->seq == seq)
	121	goto found_txb;
	122	}
	123	goto no_further_resend;
	124
	125	found_txb:
ba132d84	126	if (after(txb->serial, call->acks_highest_serial))
d57a3a15 DH	127	continue; /* Ack point not yet reached */
	128
	129	rxrpc_see_txbuf(txb, rxrpc_txbuf_see_unacked);
	130
	131	if (list_empty(&txb->tx_link)) {
d57a3a15	132	list_add_tail(&txb->tx_link, &retrans_queue);
12bdff73	133	txb->flags \|= RXRPC_TXBUF_RESENT;
33c40e24	134	}
d57a3a15	135
ba132d84	136	trace_rxrpc_retransmit(call, txb->seq, txb->serial,
d57a3a15 DH	137	ktime_to_ns(ktime_sub(txb->last_sent,
	138	max_age)));
	139
	140	if (list_is_last(&txb->call_link, &call->tx_buffer))
	141	goto no_further_resend;
	142	txb = list_next_entry(txb, call_link);
17926a79	143	}
d57a3a15	144	}
17926a79	145
d57a3a15 DH	146	/* Fast-forward through the Tx queue to the point the peer says it has
	147	* seen. Anything between the soft-ACK table and that point will get
	148	* ACK'd or NACK'd in due course, so don't worry about it here; here we
	149	* need to consider retransmitting anything beyond that point.
d57a3a15	150	*/
693f9c13	151	if (after_eq(call->acks_prev_seq, call->tx_transmitted))
d57a3a15 DH	152	goto no_further_resend;
	153
	154	list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
693f9c13	155	if (before_eq(txb->seq, call->acks_prev_seq))
d57a3a15	156	continue;
693f9c13	157	if (after(txb->seq, call->tx_transmitted))
d57a3a15 DH	158	break; /* Not transmitted yet */
	159
	160	if (ack && ack->reason == RXRPC_ACK_PING_RESPONSE &&
ba132d84	161	before(txb->serial, ntohl(ack->serial)))
d57a3a15 DH	162	goto do_resend; /* Wasn't accounted for by a more recent ping. */
	163
	164	if (ktime_after(txb->last_sent, max_age)) {
	165	if (ktime_before(txb->last_sent, oldest))
	166	oldest = txb->last_sent;
	167	continue;
	168	}
	169
	170	do_resend:
	171	unacked = true;
	172	if (list_empty(&txb->tx_link)) {
d57a3a15	173	list_add_tail(&txb->tx_link, &retrans_queue);
12bdff73	174	txb->flags \|= RXRPC_TXBUF_RESENT;
d57a3a15 DH	175	rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);
d57a3a15 DH	176	}
dfa7d920	177	}
248f219c	178
d57a3a15	179	no_further_resend:
d57a3a15	180	no_resend:
59299aa1	181	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
a4ea4c47 DH	182	resend_at += jiffies + rxrpc_get_rto_backoff(call->peer,
a4ea4c47 DH	183	!list_empty(&retrans_queue));
d73f3a74	184	call->resend_at = resend_at;
248f219c	185
57494343 DH	186	if (unacked)
	187	rxrpc_congestion_timeout(call);
	188
	189	/* If there was nothing that needed retransmission then it's likely
	190	* that an ACK got lost somewhere. Send a ping to find out instead of
	191	* retransmitting data.
	192	*/
a4ea4c47	193	if (list_empty(&retrans_queue)) {
5e6ef4f1	194	rxrpc_reduce_call_timer(call, resend_at, jiffies,
a158bdd3	195	rxrpc_timer_set_for_resend);
57494343	196	ack_ts = ktime_sub(now, call->acks_latest_ts);
c410bf01	197	if (ktime_to_us(ack_ts) < (call->peer->srtt_us >> 3))
57494343	198	goto out;
72f0c6fb DH	199	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
72f0c6fb DH	200	rxrpc_propose_ack_ping_for_lost_ack);
57494343 DH	201	goto out;
	202	}
	203
5e6ef4f1	204	/* Retransmit the queue */
a4ea4c47 DH	205	while ((txb = list_first_entry_or_null(&retrans_queue,
	206	struct rxrpc_txbuf, tx_link))) {
	207	list_del_init(&txb->tx_link);
5e6ef4f1	208	rxrpc_transmit_one(call, txb);
dfa7d920	209	}
248f219c	210
57494343	211	out:
248f219c	212	_leave("");
17926a79 DH	213	}
17926a79 DH	214
2d689424 DH	215	/*
	216	* Start transmitting the reply to a service. This cancels the need to ACK the
	217	* request if we haven't yet done so.
	218	*/
	219	static void rxrpc_begin_service_reply(struct rxrpc_call *call)
	220	{
96b4059f	221	unsigned long now = jiffies;
2d689424	222
96b4059f	223	rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
d73f3a74	224	call->delay_ack_at = now + MAX_JIFFY_OFFSET;
96b4059f DH	225	if (call->ackr_reason == RXRPC_ACK_DELAY)
	226	call->ackr_reason = 0;
	227	trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
2d689424 DH	228	}
	229
	230	/*
	231	* Close the transmission phase. After this point there is no more data to be
	232	* transmitted in the call.
	233	*/
	234	static void rxrpc_close_tx_phase(struct rxrpc_call *call)
	235	{
	236	_debug("________awaiting reply/ACK__________");
	237
96b4059f	238	switch (__rxrpc_call_state(call)) {
2d689424	239	case RXRPC_CALL_CLIENT_SEND_REQUEST:
96b4059f	240	rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY);
2d689424 DH	241	break;
2d689424 DH	242	case RXRPC_CALL_SERVER_SEND_REPLY:
96b4059f	243	rxrpc_set_call_state(call, RXRPC_CALL_SERVER_AWAIT_ACK);
2d689424 DH	244	break;
	245	default:
	246	break;
	247	}
2d689424 DH	248	}
2d689424 DH	249
cf37b598 DH	250	static bool rxrpc_tx_window_has_space(struct rxrpc_call *call)
	251	{
	252	unsigned int winsize = min_t(unsigned int, call->tx_winsize,
	253	call->cong_cwnd + call->cong_extra);
	254	rxrpc_seq_t window = call->acks_hard_ack, wtop = window + winsize;
	255	rxrpc_seq_t tx_top = call->tx_top;
	256	int space;
	257
	258	space = wtop - tx_top;
	259	return space > 0;
	260	}
	261
	262	/*
	263	* Decant some if the sendmsg prepared queue into the transmission buffer.
	264	*/
	265	static void rxrpc_decant_prepared_tx(struct rxrpc_call *call)
	266	{
	267	struct rxrpc_txbuf *txb;
	268
a343b174 DH	269	if (!test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
	270	if (list_empty(&call->tx_sendmsg))
	271	return;
cf37b598	272	rxrpc_expose_client_call(call);
a343b174	273	}
cf37b598 DH	274
	275	while ((txb = list_first_entry_or_null(&call->tx_sendmsg,
	276	struct rxrpc_txbuf, call_link))) {
	277	spin_lock(&call->tx_lock);
	278	list_del(&txb->call_link);
	279	spin_unlock(&call->tx_lock);
	280
	281	call->tx_top = txb->seq;
	282	list_add_tail(&txb->call_link, &call->tx_buffer);
	283
12bdff73	284	if (txb->flags & RXRPC_LAST_PACKET)
2d689424 DH	285	rxrpc_close_tx_phase(call);
2d689424 DH	286
cf37b598 DH	287	rxrpc_transmit_one(call, txb);
cf37b598 DH	288
cf37b598 DH	289	if (!rxrpc_tx_window_has_space(call))
	290	break;
	291	}
	292	}
	293
	294	static void rxrpc_transmit_some_data(struct rxrpc_call *call)
	295	{
96b4059f	296	switch (__rxrpc_call_state(call)) {
cf37b598 DH	297	case RXRPC_CALL_SERVER_ACK_REQUEST:
	298	if (list_empty(&call->tx_sendmsg))
	299	return;
2d689424	300	rxrpc_begin_service_reply(call);
cf37b598 DH	301	fallthrough;
	302
	303	case RXRPC_CALL_SERVER_SEND_REPLY:
cf37b598	304	case RXRPC_CALL_CLIENT_SEND_REQUEST:
cf37b598 DH	305	if (!rxrpc_tx_window_has_space(call))
cf37b598 DH	306	return;
32cf8edb DH	307	if (list_empty(&call->tx_sendmsg)) {
32cf8edb DH	308	rxrpc_inc_stat(call->rxnet, stat_tx_data_underflow);
cf37b598	309	return;
32cf8edb	310	}
cf37b598 DH	311	rxrpc_decant_prepared_tx(call);
	312	break;
	313	default:
	314	return;
	315	}
	316	}
	317
5e6ef4f1 DH	318	/*
	319	* Ping the other end to fill our RTT cache and to retrieve the rwind
	320	* and MTU parameters.
	321	*/
	322	static void rxrpc_send_initial_ping(struct rxrpc_call *call)
	323	{
	324	if (call->peer->rtt_count < 3 \|\|
	325	ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
	326	ktime_get_real()))
	327	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
	328	rxrpc_propose_ack_ping_for_params);
	329	}
	330
17926a79	331	/*
248f219c	332	* Handle retransmission and deferred ACK/abort generation.
17926a79	333	*/
57af281e	334	bool rxrpc_input_call_event(struct rxrpc_call call, struct sk_buff skb)
17926a79	335	{
a158bdd3	336	unsigned long now, next, t;
5e6ef4f1	337	bool resend = false, expired = false;
a343b174	338	s32 abort_code;
17926a79	339
cb0fc0c9	340	rxrpc_see_call(call, rxrpc_call_see_input);
e34d4234	341
17926a79	342	//printk("\n--------------------\n");
248f219c	343	_enter("{%d,%s,%lx}",
96b4059f DH	344	call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)],
96b4059f DH	345	call->events);
17926a79	346
96b4059f	347	if (__rxrpc_call_is_complete(call))
5e6ef4f1	348	goto out;
17926a79	349
a343b174 DH	350	/* Handle abort request locklessly, vs rxrpc_propose_abort(). */
	351	abort_code = smp_load_acquire(&call->send_abort);
	352	if (abort_code) {
57af281e DH	353	rxrpc_abort_call(call, 0, call->send_abort, call->send_abort_err,
57af281e DH	354	call->send_abort_why);
a343b174 DH	355	goto out;
	356	}
	357
5e6ef4f1	358	if (skb && skb->mark == RXRPC_SKB_MARK_ERROR)
3feda9d6	359	goto out;
17926a79	360
5e6ef4f1	361	/* If we see our async-event poke, check for timeout trippage. */
a158bdd3	362	now = jiffies;
d73f3a74	363	t = call->expect_rx_by;
a158bdd3 DH	364	if (time_after_eq(now, t)) {
a158bdd3 DH	365	trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
5e6ef4f1	366	expired = true;
a158bdd3 DH	367	}
a158bdd3 DH	368
d73f3a74	369	t = call->expect_req_by;
96b4059f	370	if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST &&
a158bdd3 DH	371	time_after_eq(now, t)) {
a158bdd3 DH	372	trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
5e6ef4f1	373	expired = true;
a158bdd3 DH	374	}
	375
	376	t = READ_ONCE(call->expect_term_by);
	377	if (time_after_eq(now, t)) {
	378	trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
5e6ef4f1	379	expired = true;
a158bdd3 DH	380	}
a158bdd3 DH	381
d73f3a74	382	t = call->delay_ack_at;
a158bdd3 DH	383	if (time_after_eq(now, t)) {
a158bdd3 DH	384	trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
d73f3a74	385	call->delay_ack_at = now + MAX_JIFFY_OFFSET;
e7870cf1	386	rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
530403d9	387	rxrpc_propose_ack_ping_for_lost_ack);
a158bdd3 DH	388	}
a158bdd3 DH	389
d73f3a74	390	t = call->ack_lost_at;
bd1fdf8c DH	391	if (time_after_eq(now, t)) {
bd1fdf8c DH	392	trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
d73f3a74	393	call->ack_lost_at = now + MAX_JIFFY_OFFSET;
bd1fdf8c DH	394	set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
	395	}
	396
d73f3a74	397	t = call->keepalive_at;
415f44e4 DH	398	if (time_after_eq(now, t)) {
415f44e4 DH	399	trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
d73f3a74	400	call->keepalive_at = now + MAX_JIFFY_OFFSET;
72f0c6fb DH	401	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
72f0c6fb DH	402	rxrpc_propose_ack_ping_for_keepalive);
415f44e4 DH	403	}
415f44e4 DH	404
d73f3a74	405	t = call->ping_at;
a158bdd3 DH	406	if (time_after_eq(now, t)) {
a158bdd3 DH	407	trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
d73f3a74	408	call->ping_at = now + MAX_JIFFY_OFFSET;
72f0c6fb DH	409	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
72f0c6fb DH	410	rxrpc_propose_ack_ping_for_keepalive);
a158bdd3 DH	411	}
a158bdd3 DH	412
d73f3a74	413	t = call->resend_at;
a158bdd3 DH	414	if (time_after_eq(now, t)) {
a158bdd3 DH	415	trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
d73f3a74	416	call->resend_at = now + MAX_JIFFY_OFFSET;
5e6ef4f1	417	resend = true;
a158bdd3 DH	418	}
a158bdd3 DH	419
5e6ef4f1 DH	420	if (skb)
	421	rxrpc_input_call_packet(call, skb);
	422
cf37b598 DH	423	rxrpc_transmit_some_data(call);
cf37b598 DH	424
5086d9a9 DH	425	if (skb) {
	426	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	427
	428	if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK)
	429	rxrpc_congestion_degrade(call);
	430	}
	431
5e6ef4f1 DH	432	if (test_and_clear_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events))
	433	rxrpc_send_initial_ping(call);
	434
a158bdd3	435	/* Process events */
5e6ef4f1	436	if (expired) {
1a025028 DH	437	if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
	438	(int)call->conn->hi_serial - (int)call->rx_serial > 0) {
	439	trace_rxrpc_call_reset(call);
57af281e DH	440	rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ECONNRESET,
57af281e DH	441	rxrpc_abort_call_reset);
1a025028	442	} else {
57af281e DH	443	rxrpc_abort_call(call, 0, RX_CALL_TIMEOUT, -ETIME,
57af281e DH	444	rxrpc_abort_call_timeout);
1a025028	445	}
5e6ef4f1	446	goto out;
17926a79 DH	447	}
17926a79 DH	448
5e6ef4f1	449	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
72f0c6fb DH	450	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
72f0c6fb DH	451	rxrpc_propose_ack_ping_for_lost_ack);
a5af7e1f	452
96b4059f	453	if (resend && __rxrpc_call_state(call) != RXRPC_CALL_CLIENT_RECV_REPLY)
5e6ef4f1 DH	454	rxrpc_resend(call, NULL);
	455
	456	if (test_and_clear_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
	457	rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
	458	rxrpc_propose_ack_rx_idle);
	459
5bbf9533	460	if (call->ackr_nr_unacked > 2) {
84e28aa5 DH	461	if (call->peer->rtt_count < 3)
	462	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
	463	rxrpc_propose_ack_ping_for_rtt);
	464	else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
	465	ktime_get_real()))
	466	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
	467	rxrpc_propose_ack_ping_for_old_rtt);
	468	else
	469	rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
	470	rxrpc_propose_ack_input_data);
	471	}
17926a79	472
a158bdd3	473	/* Make sure the timer is restarted */
96b4059f	474	if (!__rxrpc_call_is_complete(call)) {
5e6ef4f1	475	next = call->expect_rx_by;
a158bdd3 DH	476
a158bdd3 DH	477	#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
3d7682af	478
5e6ef4f1 DH	479	set(call->expect_req_by);
	480	set(call->expect_term_by);
	481	set(call->delay_ack_at);
	482	set(call->ack_lost_at);
	483	set(call->resend_at);
	484	set(call->keepalive_at);
	485	set(call->ping_at);
a158bdd3	486
5e6ef4f1 DH	487	now = jiffies;
	488	if (time_after_eq(now, next))
	489	rxrpc_poke_call(call, rxrpc_call_poke_timer_now);
17926a79	490
5e6ef4f1 DH	491	rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
5e6ef4f1 DH	492	}
17926a79	493
248f219c	494	out:
96b4059f	495	if (__rxrpc_call_is_complete(call)) {
5e6ef4f1	496	del_timer_sync(&call->timer);
03fc55ad DH	497	if (!test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
	498	rxrpc_disconnect_call(call);
	499	if (call->security)
	500	call->security->free_call_crypto(call);
	501	}
5e6ef4f1 DH	502	if (call->acks_hard_ack != call->tx_bottom)
5e6ef4f1 DH	503	rxrpc_shrink_call_tx_buffer(call);
17926a79	504	_leave("");
57af281e	505	return true;
17926a79	506	}