net/rxrpc/call_event.c - kernel/common - Git at Google

 // 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 ([email protected])
  */

 #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)
 {
 	ktime_t delay = ms_to_ktime(READ_ONCE(rxrpc_idle_ack_delay));
 	ktime_t now = ktime_get_real();
 	ktime_t ping_at = ktime_add(now, delay);

 	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
 	if (ktime_before(ping_at, call->ping_at)) {
 		call->ping_at = ping_at;
 		trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_ping);
 	}
 }

 /*
  * 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)
 {
 	ktime_t now = ktime_get_real(), delay;

 	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);

 	if (call->srtt_us)
 		delay = (call->srtt_us >> 3) * NSEC_PER_USEC;
 	else
 		delay = ms_to_ktime(READ_ONCE(rxrpc_soft_ack_delay));
 	ktime_add_ms(delay, call->tx_backoff);

 	call->delay_ack_at = ktime_add(now, delay);
 	trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_delayed_ack);
 }

 /*
  * Retransmit one or more packets.
  */
 static bool rxrpc_retransmit_data(struct rxrpc_call *call,
 				  struct rxrpc_send_data_req *req)
 {
 	struct rxrpc_txqueue *tq = req->tq;
 	unsigned int ix = req->seq & RXRPC_TXQ_MASK;
 	struct rxrpc_txbuf *txb = tq->bufs[ix];

 	_enter("%x,%x,%x,%x", tq->qbase, req->seq, ix, txb->debug_id);

 	req->retrans = true;
 	trace_rxrpc_retransmit(call, req, txb);

 	txb->flags |= RXRPC_TXBUF_RESENT;
 	rxrpc_send_data_packet(call, req);
 	rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);

 	req->tq		= NULL;
 	req->n		= 0;
 	req->did_send	= true;
 	req->now	= ktime_get_real();
 	return true;
 }

 /*
  * Perform retransmission of NAK'd and unack'd packets.
  */
 static void rxrpc_resend(struct rxrpc_call *call)
 {
 	struct rxrpc_send_data_req req = {
 		.now	= ktime_get_real(),
 		.trace	= rxrpc_txdata_retransmit,
 	};
 	struct rxrpc_txqueue *tq;

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

 	trace_rxrpc_resend(call, call->acks_highest_serial);

 	/* Scan the transmission queue, looking for lost packets. */
 	for (tq = call->tx_queue; tq; tq = tq->next) {
 		unsigned long lost = tq->segment_lost;

 		if (after(tq->qbase, call->tx_transmitted))
 			break;

 		_debug("retr %16lx %u c=%08x [%x]",
 		       tq->segment_acked, tq->nr_reported_acks, call->debug_id, tq->qbase);
 		_debug("lost %16lx", lost);

 		trace_rxrpc_resend_lost(call, tq, lost);
 		while (lost) {
 			unsigned int ix = __ffs(lost);
 			struct rxrpc_txbuf *txb = tq->bufs[ix];

 			__clear_bit(ix, &lost);
 			rxrpc_see_txbuf(txb, rxrpc_txbuf_see_lost);

 			req.tq  = tq;
 			req.seq = tq->qbase + ix;
 			req.n   = 1;
 			rxrpc_retransmit_data(call, &req);
 		}
 	}

 	rxrpc_get_rto_backoff(call, req.did_send);
 	_leave("");
 }

 /*
  * Resend the highest-seq DATA packet so far transmitted for RACK-TLP [RFC8985 7.3].
  */
 void rxrpc_resend_tlp(struct rxrpc_call *call)
 {
 	struct rxrpc_send_data_req req = {
 		.now		= ktime_get_real(),
 		.seq		= call->tx_transmitted,
 		.n		= 1,
 		.tlp_probe	= true,
 		.trace		= rxrpc_txdata_tlp_retransmit,
 	};

 	/* There's a chance it'll be on the tail segment of the queue. */
 	req.tq = READ_ONCE(call->tx_qtail);
 	if (req.tq &&
 	    before(call->tx_transmitted, req.tq->qbase + RXRPC_NR_TXQUEUE)) {
 		rxrpc_retransmit_data(call, &req);
 		return;
 	}

 	for (req.tq = call->tx_queue; req.tq; req.tq = req.tq->next) {
 		if (after_eq(call->tx_transmitted, req.tq->qbase) &&
 		    before(call->tx_transmitted, req.tq->qbase + RXRPC_NR_TXQUEUE)) {
 			rxrpc_retransmit_data(call, &req);
 			return;
 		}
 	}
 }

 /*
  * 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)
 {
 	rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
 	if (call->ackr_reason == RXRPC_ACK_DELAY)
 		call->ackr_reason = 0;
 	call->delay_ack_at = KTIME_MAX;
 	trace_rxrpc_timer_can(call, rxrpc_timer_trace_delayed_ack);
 }

 /*
  * 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;
 	}
 }

 /*
  * Transmit some as-yet untransmitted data, to a maximum of the supplied limit.
  */
 static void rxrpc_transmit_fresh_data(struct rxrpc_call *call, unsigned int limit,
 				      enum rxrpc_txdata_trace trace)
 {
 	int space = rxrpc_tx_window_space(call);

 	if (!test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
 		if (call->send_top == call->tx_top)
 			return;
 		rxrpc_expose_client_call(call);
 	}

 	while (space > 0) {
 		struct rxrpc_send_data_req req = {
 			.now	= ktime_get_real(),
 			.seq	= call->tx_transmitted + 1,
 			.n	= 0,
 			.trace	= trace,
 		};
 		struct rxrpc_txqueue *tq;
 		struct rxrpc_txbuf *txb;
 		rxrpc_seq_t send_top, seq;
 		int limit = min(space, max(call->peer->pmtud_jumbo, 1));

 		/* Order send_top before the contents of the new txbufs and
 		 * txqueue pointers
 		 */
 		send_top = smp_load_acquire(&call->send_top);
 		if (call->tx_top == send_top)
 			break;

 		trace_rxrpc_transmit(call, send_top, space);

 		tq = call->tx_qtail;
 		seq = call->tx_top;
 		trace_rxrpc_tq(call, tq, seq, rxrpc_tq_decant);

 		do {
 			int ix;

 			seq++;
 			ix = seq & RXRPC_TXQ_MASK;
 			if (!ix) {
 				tq = tq->next;
 				trace_rxrpc_tq(call, tq, seq, rxrpc_tq_decant_advance);
 			}
 			if (!req.tq)
 				req.tq = tq;
 			txb = tq->bufs[ix];
 			req.n++;
 			if (!txb->jumboable)
 				break;
 		} while (req.n < limit && before(seq, send_top));

 		if (txb->flags & RXRPC_LAST_PACKET) {
 			rxrpc_close_tx_phase(call);
 			tq = NULL;
 		}
 		call->tx_qtail = tq;
 		call->tx_top = seq;

 		space -= req.n;
 		rxrpc_send_data_packet(call, &req);
 	}
 }

 void rxrpc_transmit_some_data(struct rxrpc_call *call, unsigned int limit,
 			      enum rxrpc_txdata_trace trace)
 {
 	switch (__rxrpc_call_state(call)) {
 	case RXRPC_CALL_SERVER_ACK_REQUEST:
 		if (call->tx_bottom == READ_ONCE(call->send_top))
 			return;
 		rxrpc_begin_service_reply(call);
 		fallthrough;

 	case RXRPC_CALL_SERVER_SEND_REPLY:
 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 		if (!rxrpc_tx_window_space(call))
 			return;
 		if (call->tx_bottom == READ_ONCE(call->send_top)) {
 			rxrpc_inc_stat(call->rxnet, stat_tx_data_underflow);
 			return;
 		}
 		rxrpc_transmit_fresh_data(call, limit, trace);
 		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->rtt_count < 3 ||
 	    ktime_before(ktime_add_ms(call->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;
 	ktime_t now, t;
 	bool did_receive = false, saw_ack = 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);

 	/* 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;
 	}

 	do {
 		skb = __skb_dequeue(&call->rx_queue);
 		if (skb) {
 			struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

 			if (__rxrpc_call_is_complete(call) ||
 			    skb->mark == RXRPC_SKB_MARK_ERROR) {
 				rxrpc_free_skb(skb, rxrpc_skb_put_call_rx);
 				goto out;
 			}

 			saw_ack |= sp->hdr.type == RXRPC_PACKET_TYPE_ACK;

 			rxrpc_input_call_packet(call, skb);
 			rxrpc_free_skb(skb, rxrpc_skb_put_call_rx);
 			did_receive = true;
 		}

 		t = ktime_sub(call->rack_timo_at, ktime_get_real());
 		if (t <= 0) {
 			trace_rxrpc_timer_exp(call, t,
 					      rxrpc_timer_trace_rack_off + call->rack_timer_mode);
 			call->rack_timo_at = KTIME_MAX;
 			rxrpc_rack_timer_expired(call, t);
 		}

 	} while (!skb_queue_empty(&call->rx_queue));

 	/* If we see our async-event poke, check for timeout trippage. */
 	now = ktime_get_real();
 	t = ktime_sub(call->expect_rx_by, now);
 	if (t <= 0) {
 		trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_expect_rx);
 		goto expired;
 	}

 	t = ktime_sub(call->expect_req_by, now);
 	if (t <= 0) {
 		call->expect_req_by = KTIME_MAX;
 		if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST) {
 			trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_idle);
 			goto expired;
 		}
 	}

 	t = ktime_sub(READ_ONCE(call->expect_term_by), now);
 	if (t <= 0) {
 		trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_hard);
 		goto expired;
 	}

 	t = ktime_sub(call->delay_ack_at, now);
 	if (t <= 0) {
 		trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_delayed_ack);
 		call->delay_ack_at = KTIME_MAX;
 		rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
 			       rxrpc_propose_ack_delayed_ack);
 	}

 	t = ktime_sub(call->ping_at, now);
 	if (t <= 0) {
 		trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_ping);
 		call->ping_at = KTIME_MAX;
 		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
 			       rxrpc_propose_ack_ping_for_keepalive);
 	}

 	now = ktime_get_real();
 	t = ktime_sub(call->keepalive_at, now);
 	if (t <= 0) {
 		trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_keepalive);
 		call->keepalive_at = KTIME_MAX;
 		rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
 			       rxrpc_propose_ack_ping_for_keepalive);
 	}

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

 	rxrpc_transmit_some_data(call, UINT_MAX, rxrpc_txdata_new_data);

 	if (saw_ack)
 		rxrpc_congestion_degrade(call);

 	if (did_receive &&
 	    (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 	     __rxrpc_call_state(call) == RXRPC_CALL_SERVER_SEND_REPLY)) {
 		t = ktime_sub(call->rack_timo_at, ktime_get_real());
 		trace_rxrpc_rack(call, t);
 	}

 	/* Process events */
 	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 (call->tx_nr_lost > 0 &&
 	    __rxrpc_call_state(call) != RXRPC_CALL_CLIENT_RECV_REPLY &&
 	    !test_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags))
 		rxrpc_resend(call);

 	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->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->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)) {
 		ktime_t next = READ_ONCE(call->expect_term_by), delay;

 #define set(T) { ktime_t _t = (T); if (ktime_before(_t, next)) next = _t; }

 		set(call->expect_req_by);
 		set(call->expect_rx_by);
 		set(call->delay_ack_at);
 		set(call->rack_timo_at);
 		set(call->keepalive_at);
 		set(call->ping_at);

 		now = ktime_get_real();
 		delay = ktime_sub(next, now);
 		if (delay <= 0) {
 			rxrpc_poke_call(call, rxrpc_call_poke_timer_now);
 		} else {
 			unsigned long nowj = jiffies, delayj, nextj;

 			delayj = umax(nsecs_to_jiffies(delay), 1);
 			nextj = nowj + delayj;
 			if (time_before(nextj, call->timer.expires) ||
 			    !timer_pending(&call->timer)) {
 				trace_rxrpc_timer_restart(call, delay, delayj);
 				timer_reduce(&call->timer, nextj);
 			}
 		}
 	}

 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);
 	} else {
 		if (did_receive &&
 		    call->peer->ackr_adv_pmtud &&
 		    call->peer->pmtud_pending)
 			rxrpc_send_probe_for_pmtud(call);
 	}
 	_leave("");
 	return true;

 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;
 }
	// 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 ([email protected])
	*/

	#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)
	{
	ktime_t delay = ms_to_ktime(READ_ONCE(rxrpc_idle_ack_delay));
	ktime_t now = ktime_get_real();
	ktime_t ping_at = ktime_add(now, delay);

	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
	if (ktime_before(ping_at, call->ping_at)) {
	call->ping_at = ping_at;
	trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_ping);
	}
	}

	/*
	* 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)
	{
	ktime_t now = ktime_get_real(), delay;

	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);

	if (call->srtt_us)
	delay = (call->srtt_us >> 3) * NSEC_PER_USEC;
	else
	delay = ms_to_ktime(READ_ONCE(rxrpc_soft_ack_delay));
	ktime_add_ms(delay, call->tx_backoff);

	call->delay_ack_at = ktime_add(now, delay);
	trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_delayed_ack);
	}

	/*
	* Retransmit one or more packets.
	*/
	static bool rxrpc_retransmit_data(struct rxrpc_call *call,
	struct rxrpc_send_data_req *req)
	{
	struct rxrpc_txqueue *tq = req->tq;
	unsigned int ix = req->seq & RXRPC_TXQ_MASK;
	struct rxrpc_txbuf *txb = tq->bufs[ix];

	_enter("%x,%x,%x,%x", tq->qbase, req->seq, ix, txb->debug_id);

	req->retrans = true;
	trace_rxrpc_retransmit(call, req, txb);

	txb->flags \|= RXRPC_TXBUF_RESENT;
	rxrpc_send_data_packet(call, req);
	rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);

	req->tq = NULL;
	req->n = 0;
	req->did_send = true;
	req->now = ktime_get_real();
	return true;
	}

	/*
	* Perform retransmission of NAK'd and unack'd packets.
	*/
	static void rxrpc_resend(struct rxrpc_call *call)
	{
	struct rxrpc_send_data_req req = {
	.now = ktime_get_real(),
	.trace = rxrpc_txdata_retransmit,
	};
	struct rxrpc_txqueue *tq;

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

	trace_rxrpc_resend(call, call->acks_highest_serial);

	/* Scan the transmission queue, looking for lost packets. */
	for (tq = call->tx_queue; tq; tq = tq->next) {
	unsigned long lost = tq->segment_lost;

	if (after(tq->qbase, call->tx_transmitted))
	break;

	_debug("retr %16lx %u c=%08x [%x]",
	tq->segment_acked, tq->nr_reported_acks, call->debug_id, tq->qbase);
	_debug("lost %16lx", lost);

	trace_rxrpc_resend_lost(call, tq, lost);
	while (lost) {
	unsigned int ix = __ffs(lost);
	struct rxrpc_txbuf *txb = tq->bufs[ix];

	__clear_bit(ix, &lost);
	rxrpc_see_txbuf(txb, rxrpc_txbuf_see_lost);

	req.tq = tq;
	req.seq = tq->qbase + ix;
	req.n = 1;
	rxrpc_retransmit_data(call, &req);
	}
	}

	rxrpc_get_rto_backoff(call, req.did_send);
	_leave("");
	}

	/*
	* Resend the highest-seq DATA packet so far transmitted for RACK-TLP [RFC8985 7.3].
	*/
	void rxrpc_resend_tlp(struct rxrpc_call *call)
	{
	struct rxrpc_send_data_req req = {
	.now = ktime_get_real(),
	.seq = call->tx_transmitted,
	.n = 1,
	.tlp_probe = true,
	.trace = rxrpc_txdata_tlp_retransmit,
	};

	/* There's a chance it'll be on the tail segment of the queue. */
	req.tq = READ_ONCE(call->tx_qtail);
	if (req.tq &&
	before(call->tx_transmitted, req.tq->qbase + RXRPC_NR_TXQUEUE)) {
	rxrpc_retransmit_data(call, &req);
	return;
	}

	for (req.tq = call->tx_queue; req.tq; req.tq = req.tq->next) {
	if (after_eq(call->tx_transmitted, req.tq->qbase) &&
	before(call->tx_transmitted, req.tq->qbase + RXRPC_NR_TXQUEUE)) {
	rxrpc_retransmit_data(call, &req);
	return;
	}
	}
	}

	/*
	* 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)
	{
	rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
	if (call->ackr_reason == RXRPC_ACK_DELAY)
	call->ackr_reason = 0;
	call->delay_ack_at = KTIME_MAX;
	trace_rxrpc_timer_can(call, rxrpc_timer_trace_delayed_ack);
	}

	/*
	* 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;
	}
	}

	/*
	* Transmit some as-yet untransmitted data, to a maximum of the supplied limit.
	*/
	static void rxrpc_transmit_fresh_data(struct rxrpc_call *call, unsigned int limit,
	enum rxrpc_txdata_trace trace)
	{
	int space = rxrpc_tx_window_space(call);

	if (!test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
	if (call->send_top == call->tx_top)
	return;
	rxrpc_expose_client_call(call);
	}

	while (space > 0) {
	struct rxrpc_send_data_req req = {
	.now = ktime_get_real(),
	.seq = call->tx_transmitted + 1,
	.n = 0,
	.trace = trace,
	};
	struct rxrpc_txqueue *tq;
	struct rxrpc_txbuf *txb;
	rxrpc_seq_t send_top, seq;
	int limit = min(space, max(call->peer->pmtud_jumbo, 1));

	/* Order send_top before the contents of the new txbufs and
	* txqueue pointers
	*/
	send_top = smp_load_acquire(&call->send_top);
	if (call->tx_top == send_top)
	break;

	trace_rxrpc_transmit(call, send_top, space);

	tq = call->tx_qtail;
	seq = call->tx_top;
	trace_rxrpc_tq(call, tq, seq, rxrpc_tq_decant);

	do {
	int ix;

	seq++;
	ix = seq & RXRPC_TXQ_MASK;
	if (!ix) {
	tq = tq->next;
	trace_rxrpc_tq(call, tq, seq, rxrpc_tq_decant_advance);
	}
	if (!req.tq)
	req.tq = tq;
	txb = tq->bufs[ix];
	req.n++;
	if (!txb->jumboable)
	break;
	} while (req.n < limit && before(seq, send_top));

	if (txb->flags & RXRPC_LAST_PACKET) {
	rxrpc_close_tx_phase(call);
	tq = NULL;
	}
	call->tx_qtail = tq;
	call->tx_top = seq;

	space -= req.n;
	rxrpc_send_data_packet(call, &req);
	}
	}

	void rxrpc_transmit_some_data(struct rxrpc_call *call, unsigned int limit,
	enum rxrpc_txdata_trace trace)
	{
	switch (__rxrpc_call_state(call)) {
	case RXRPC_CALL_SERVER_ACK_REQUEST:
	if (call->tx_bottom == READ_ONCE(call->send_top))
	return;
	rxrpc_begin_service_reply(call);
	fallthrough;

	case RXRPC_CALL_SERVER_SEND_REPLY:
	case RXRPC_CALL_CLIENT_SEND_REQUEST:
	if (!rxrpc_tx_window_space(call))
	return;
	if (call->tx_bottom == READ_ONCE(call->send_top)) {
	rxrpc_inc_stat(call->rxnet, stat_tx_data_underflow);
	return;
	}
	rxrpc_transmit_fresh_data(call, limit, trace);
	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->rtt_count < 3 \|\|
	ktime_before(ktime_add_ms(call->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;
	ktime_t now, t;
	bool did_receive = false, saw_ack = 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);

	/* 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;
	}

	do {
	skb = __skb_dequeue(&call->rx_queue);
	if (skb) {
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	if (__rxrpc_call_is_complete(call) \|\|
	skb->mark == RXRPC_SKB_MARK_ERROR) {
	rxrpc_free_skb(skb, rxrpc_skb_put_call_rx);
	goto out;
	}

	saw_ack \|= sp->hdr.type == RXRPC_PACKET_TYPE_ACK;

	rxrpc_input_call_packet(call, skb);
	rxrpc_free_skb(skb, rxrpc_skb_put_call_rx);
	did_receive = true;
	}

	t = ktime_sub(call->rack_timo_at, ktime_get_real());
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t,
	rxrpc_timer_trace_rack_off + call->rack_timer_mode);
	call->rack_timo_at = KTIME_MAX;
	rxrpc_rack_timer_expired(call, t);
	}

	} while (!skb_queue_empty(&call->rx_queue));

	/* If we see our async-event poke, check for timeout trippage. */
	now = ktime_get_real();
	t = ktime_sub(call->expect_rx_by, now);
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_expect_rx);
	goto expired;
	}

	t = ktime_sub(call->expect_req_by, now);
	if (t <= 0) {
	call->expect_req_by = KTIME_MAX;
	if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_idle);
	goto expired;
	}
	}

	t = ktime_sub(READ_ONCE(call->expect_term_by), now);
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_hard);
	goto expired;
	}

	t = ktime_sub(call->delay_ack_at, now);
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_delayed_ack);
	call->delay_ack_at = KTIME_MAX;
	rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
	rxrpc_propose_ack_delayed_ack);
	}

	t = ktime_sub(call->ping_at, now);
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_ping);
	call->ping_at = KTIME_MAX;
	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
	rxrpc_propose_ack_ping_for_keepalive);
	}

	now = ktime_get_real();
	t = ktime_sub(call->keepalive_at, now);
	if (t <= 0) {
	trace_rxrpc_timer_exp(call, t, rxrpc_timer_trace_keepalive);
	call->keepalive_at = KTIME_MAX;
	rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
	rxrpc_propose_ack_ping_for_keepalive);
	}

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

	rxrpc_transmit_some_data(call, UINT_MAX, rxrpc_txdata_new_data);

	if (saw_ack)
	rxrpc_congestion_degrade(call);

	if (did_receive &&
	(__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_SEND_REQUEST \|\|
	__rxrpc_call_state(call) == RXRPC_CALL_SERVER_SEND_REPLY)) {
	t = ktime_sub(call->rack_timo_at, ktime_get_real());
	trace_rxrpc_rack(call, t);
	}

	/* Process events */
	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 (call->tx_nr_lost > 0 &&
	__rxrpc_call_state(call) != RXRPC_CALL_CLIENT_RECV_REPLY &&
	!test_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags))
	rxrpc_resend(call);

	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->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->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)) {
	ktime_t next = READ_ONCE(call->expect_term_by), delay;

	#define set(T) { ktime_t _t = (T); if (ktime_before(_t, next)) next = _t; }

	set(call->expect_req_by);
	set(call->expect_rx_by);
	set(call->delay_ack_at);
	set(call->rack_timo_at);
	set(call->keepalive_at);
	set(call->ping_at);

	now = ktime_get_real();
	delay = ktime_sub(next, now);
	if (delay <= 0) {
	rxrpc_poke_call(call, rxrpc_call_poke_timer_now);
	} else {
	unsigned long nowj = jiffies, delayj, nextj;

	delayj = umax(nsecs_to_jiffies(delay), 1);
	nextj = nowj + delayj;
	if (time_before(nextj, call->timer.expires) \|\|
	!timer_pending(&call->timer)) {
	trace_rxrpc_timer_restart(call, delay, delayj);
	timer_reduce(&call->timer, nextj);
	}
	}
	}

	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);
	} else {
	if (did_receive &&
	call->peer->ackr_adv_pmtud &&
	call->peer->pmtud_pending)
	rxrpc_send_probe_for_pmtud(call);
	}
	_leave("");
	return true;

	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;
	}