[deliverable/linux.git] / net / rxrpc / call_event.c

/* 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)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#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"

/*
 * Set the timer
 */
static void rxrpc_set_timer(struct rxrpc_call *call)
{
	unsigned long t, now = jiffies;

	_enter("{%ld,%ld,%ld:%ld}",
	       call->ack_at - now, call->resend_at - now, call->expire_at - now,
	       call->timer.expires - now);
	
	read_lock_bh(&call->state_lock);

	if (call->state < RXRPC_CALL_COMPLETE) {
		t = call->ack_at;
		if (time_before(call->resend_at, t))
			t = call->resend_at;
		if (time_before(call->expire_at, t))
			t = call->expire_at;
		if (!timer_pending(&call->timer) ||
		    time_before(t, call->timer.expires)) {
			_debug("set timer %ld", t - now);
			mod_timer(&call->timer, t);
		}
	}
	read_unlock_bh(&call->state_lock);
}

/*
 * 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)
{
	unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
	s8 prior = rxrpc_ack_priority[ack_reason];

	_enter("{%d},%s,%%%x,%u",
	       call->debug_id, rxrpc_acks(ack_reason), serial, immediate);

	/* 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)) {
			call->ackr_serial = serial;
			call->ackr_skew = skew;
		}
		if (!immediate)
			return;
	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
		call->ackr_reason = ack_reason;
		call->ackr_serial = serial;
		call->ackr_skew = skew;
	}

	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_soft_ack_delay < expiry)
			expiry = rxrpc_idle_ack_delay;
		break;

	default:
		immediate = true;
		break;
	}

	now = jiffies;
	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 {
		ack_at = now + expiry;
		_debug("deferred ACK %ld < %ld", expiry, call->ack_at - now);
		if (time_before(ack_at, call->ack_at)) {
			call->ack_at = ack_at;
			rxrpc_set_timer(call);
		}
	}
}

/*
 * 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)
{
	spin_lock_bh(&call->lock);
	__rxrpc_propose_ACK(call, ack_reason, skew, serial,
			    immediate, background);
	spin_unlock_bh(&call->lock);
}

/*
 * Perform retransmission of NAK'd and unack'd packets.
 */
static void rxrpc_resend(struct rxrpc_call *call)
{
	struct rxrpc_wire_header *whdr;
	struct rxrpc_skb_priv *sp;
	struct sk_buff *skb;
	rxrpc_seq_t cursor, seq, top;
	unsigned long resend_at, now;
	int ix;
	u8 annotation;

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

	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.
	 */
	now = jiffies;
	resend_at = now + rxrpc_resend_timeout;
	seq = cursor + 1;
	do {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		if (annotation == RXRPC_TX_ANNO_ACK)
			continue;

		skb = call->rxtx_buffer[ix];
		rxrpc_see_skb(skb);
		sp = rxrpc_skb(skb);

		if (annotation == RXRPC_TX_ANNO_UNACK) {
			if (time_after(sp->resend_at, now)) {
				if (time_before(sp->resend_at, resend_at))
					resend_at = sp->resend_at;
				continue;
			}
		}

		/* Okay, we need to retransmit a packet. */
		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
		seq++;
	} while (before_eq(seq, top));

	call->resend_at = resend_at;

	/* 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.
	 */
	seq = cursor + 1;
	do {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		if (annotation != RXRPC_TX_ANNO_RETRANS)
			continue;

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

		/* Each Tx packet needs a new serial number */
		sp->hdr.serial = atomic_inc_return(&call->conn->serial);

		whdr = (struct rxrpc_wire_header *)skb->head;
		whdr->serial = htonl(sp->hdr.serial);

		if (rxrpc_send_data_packet(call->conn, skb) < 0) {
			call->resend_at = now + 2;
			rxrpc_free_skb(skb);
			return;
		}

		if (rxrpc_is_client_call(call))
			rxrpc_expose_client_call(call);
		sp->resend_at = now + rxrpc_resend_timeout;

		rxrpc_free_skb(skb);
		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) &&
		    (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_RETRANS ||
		     call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK))
			call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;

		if (after(call->tx_hard_ack, seq))
			seq = call->tx_hard_ack;
		seq++;
	} while (before_eq(seq, top));

out_unlock:
	spin_unlock_bh(&call->lock);
	_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);
	unsigned long now;

	rxrpc_see_call(call);

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

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

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

	now = jiffies;
	if (time_after_eq(now, call->expire_at)) {
		rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
	    time_after_eq(now, call->ack_at)) {
		call->ack_at = call->expire_at;
		if (call->ackr_reason) {
			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
			goto recheck_state;
		}
	}

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

	rxrpc_set_timer(call);

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

out_put:
	rxrpc_put_call(call, rxrpc_call_put);
out:
	_leave("");
}
Commit	Line	Data
17926a79 DH	1	/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
9b6d5398 JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	13
17926a79 DH	14	#include <linux/module.h>
	15	#include <linux/circ_buf.h>
	16	#include <linux/net.h>
	17	#include <linux/skbuff.h>
5a0e3ad6	18	#include <linux/slab.h>
17926a79 DH	19	#include <linux/udp.h>
	20	#include <net/sock.h>
	21	#include <net/af_rxrpc.h>
	22	#include "ar-internal.h"
	23
17926a79	24	/*
248f219c	25	* Set the timer
17926a79	26	*/
248f219c	27	static void rxrpc_set_timer(struct rxrpc_call *call)
17926a79	28	{
248f219c	29	unsigned long t, now = jiffies;
17926a79	30
248f219c DH	31	_enter("{%ld,%ld,%ld:%ld}",
	32	call->ack_at - now, call->resend_at - now, call->expire_at - now,
	33	call->timer.expires - now);
	34
	35	read_lock_bh(&call->state_lock);
17926a79	36
248f219c DH	37	if (call->state < RXRPC_CALL_COMPLETE) {
	38	t = call->ack_at;
	39	if (time_before(call->resend_at, t))
	40	t = call->resend_at;
	41	if (time_before(call->expire_at, t))
	42	t = call->expire_at;
	43	if (!timer_pending(&call->timer) \|\|
	44	time_before(t, call->timer.expires)) {
	45	_debug("set timer %ld", t - now);
	46	mod_timer(&call->timer, t);
17926a79	47	}
17926a79	48	}
17926a79 DH	49	read_unlock_bh(&call->state_lock);
	50	}
	51
	52	/*
248f219c	53	* propose an ACK be sent
17926a79	54	*/
248f219c DH	55	static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
	56	u16 skew, u32 serial, bool immediate,
	57	bool background)
17926a79	58	{
248f219c	59	unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
17926a79 DH	60	s8 prior = rxrpc_ack_priority[ack_reason];
17926a79 DH	61
248f219c DH	62	_enter("{%d},%s,%%%x,%u",
248f219c DH	63	call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
17926a79	64
248f219c DH	65	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	66	* numbers, but we don't alter the timeout.
	67	*/
	68	_debug("prior %u %u vs %u %u",
	69	ack_reason, prior,
	70	call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
	71	if (ack_reason == call->ackr_reason) {
	72	if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
	73	call->ackr_serial = serial;
	74	call->ackr_skew = skew;
17926a79	75	}
248f219c DH	76	if (!immediate)
	77	return;
	78	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
	79	call->ackr_reason = ack_reason;
	80	call->ackr_serial = serial;
	81	call->ackr_skew = skew;
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 DH	97	case RXRPC_ACK_IDLE:
	98	if (rxrpc_soft_ack_delay < expiry)
	99	expiry = rxrpc_idle_ack_delay;
	100	break;
17926a79	101
248f219c DH	102	default:
	103	immediate = true;
	104	break;
17926a79 DH	105	}
17926a79 DH	106
248f219c DH	107	now = jiffies;
	108	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
	109	_debug("already scheduled");
	110	} else if (immediate \|\| expiry == 0) {
	111	_debug("immediate ACK %lx", call->events);
	112	if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
	113	background)
	114	rxrpc_queue_call(call);
	115	} else {
	116	ack_at = now + expiry;
	117	_debug("deferred ACK %ld < %ld", expiry, call->ack_at - now);
	118	if (time_before(ack_at, call->ack_at)) {
	119	call->ack_at = ack_at;
	120	rxrpc_set_timer(call);
17926a79 DH	121	}
17926a79 DH	122	}
17926a79 DH	123	}
	124
	125	/*
248f219c	126	* propose an ACK be sent, locking the call structure
17926a79	127	*/
248f219c DH	128	void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
248f219c DH	129	u16 skew, u32 serial, bool immediate, bool background)
17926a79	130	{
248f219c DH	131	spin_lock_bh(&call->lock);
	132	__rxrpc_propose_ACK(call, ack_reason, skew, serial,
	133	immediate, background);
	134	spin_unlock_bh(&call->lock);
17926a79 DH	135	}
	136
	137	/*
248f219c	138	* Perform retransmission of NAK'd and unack'd packets.
17926a79	139	*/
248f219c	140	static void rxrpc_resend(struct rxrpc_call *call)
17926a79	141	{
248f219c	142	struct rxrpc_wire_header *whdr;
17926a79 DH	143	struct rxrpc_skb_priv *sp;
17926a79 DH	144	struct sk_buff *skb;
248f219c DH	145	rxrpc_seq_t cursor, seq, top;
	146	unsigned long resend_at, now;
	147	int ix;
	148	u8 annotation;
17926a79	149
248f219c	150	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
17926a79 DH	151
	152	spin_lock_bh(&call->lock);
	153
248f219c DH	154	cursor = call->tx_hard_ack;
	155	top = call->tx_top;
	156	ASSERT(before_eq(cursor, top));
	157	if (cursor == top)
	158	goto out_unlock;
	159
	160	/* Scan the packet list without dropping the lock and decide which of
	161	* the packets in the Tx buffer we're going to resend and what the new
	162	* resend timeout will be.
	163	*/
	164	now = jiffies;
	165	resend_at = now + rxrpc_resend_timeout;
	166	seq = cursor + 1;
	167	do {
	168	ix = seq & RXRPC_RXTX_BUFF_MASK;
	169	annotation = call->rxtx_annotations[ix];
	170	if (annotation == RXRPC_TX_ANNO_ACK)
	171	continue;
17926a79	172
248f219c	173	skb = call->rxtx_buffer[ix];
df844fd4	174	rxrpc_see_skb(skb);
17926a79 DH	175	sp = rxrpc_skb(skb);
17926a79 DH	176
248f219c DH	177	if (annotation == RXRPC_TX_ANNO_UNACK) {
	178	if (time_after(sp->resend_at, now)) {
	179	if (time_before(sp->resend_at, resend_at))
	180	resend_at = sp->resend_at;
	181	continue;
33c40e24	182	}
17926a79	183	}
17926a79	184
248f219c DH	185	/* Okay, we need to retransmit a packet. */
	186	call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
	187	seq++;
	188	} while (before_eq(seq, top));
	189
	190	call->resend_at = resend_at;
	191
	192	/* Now go through the Tx window and perform the retransmissions. We
	193	* have to drop the lock for each send. If an ACK comes in whilst the
	194	* lock is dropped, it may clear some of the retransmission markers for
	195	* packets that it soft-ACKs.
	196	*/
	197	seq = cursor + 1;
	198	do {
	199	ix = seq & RXRPC_RXTX_BUFF_MASK;
	200	annotation = call->rxtx_annotations[ix];
	201	if (annotation != RXRPC_TX_ANNO_RETRANS)
	202	continue;
17926a79	203
248f219c DH	204	skb = call->rxtx_buffer[ix];
248f219c DH	205	rxrpc_get_skb(skb);
17926a79	206	spin_unlock_bh(&call->lock);
248f219c	207	sp = rxrpc_skb(skb);
17926a79	208
248f219c DH	209	/* Each Tx packet needs a new serial number */
248f219c DH	210	sp->hdr.serial = atomic_inc_return(&call->conn->serial);
17926a79	211
248f219c DH	212	whdr = (struct rxrpc_wire_header *)skb->head;
248f219c DH	213	whdr->serial = htonl(sp->hdr.serial);
17926a79	214
248f219c DH	215	if (rxrpc_send_data_packet(call->conn, skb) < 0) {
	216	call->resend_at = now + 2;
	217	rxrpc_free_skb(skb);
	218	return;
	219	}
17926a79	220
248f219c DH	221	if (rxrpc_is_client_call(call))
	222	rxrpc_expose_client_call(call);
	223	sp->resend_at = now + rxrpc_resend_timeout;
17926a79	224
248f219c	225	rxrpc_free_skb(skb);
17926a79	226	spin_lock_bh(&call->lock);
17926a79	227
248f219c DH	228	/* We need to clear the retransmit state, but there are two
	229	* things we need to be aware of: A new ACK/NAK might have been
	230	* received and the packet might have been hard-ACK'd (in which
	231	* case it will no longer be in the buffer).
	232	*/
	233	if (after(seq, call->tx_hard_ack) &&
	234	(call->rxtx_annotations[ix] == RXRPC_TX_ANNO_RETRANS \|\|
	235	call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK))
	236	call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;
	237
	238	if (after(call->tx_hard_ack, seq))
	239	seq = call->tx_hard_ack;
	240	seq++;
	241	} while (before_eq(seq, top));
	242
	243	out_unlock:
	244	spin_unlock_bh(&call->lock);
	245	_leave("");
17926a79 DH	246	}
	247
	248	/*
248f219c	249	* Handle retransmission and deferred ACK/abort generation.
17926a79 DH	250	*/
	251	void rxrpc_process_call(struct work_struct *work)
	252	{
	253	struct rxrpc_call *call =
	254	container_of(work, struct rxrpc_call, processor);
248f219c	255	unsigned long now;
17926a79	256
e34d4234 DH	257	rxrpc_see_call(call);
e34d4234 DH	258
17926a79	259	//printk("\n--------------------\n");
248f219c DH	260	_enter("{%d,%s,%lx}",
248f219c DH	261	call->debug_id, rxrpc_call_states[call->state], call->events);
17926a79	262
248f219c DH	263	recheck_state:
	264	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
	265	rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
	266	goto recheck_state;
17926a79 DH	267	}
17926a79 DH	268
248f219c DH	269	if (call->state == RXRPC_CALL_COMPLETE) {
	270	del_timer_sync(&call->timer);
	271	goto out_put;
17926a79 DH	272	}
17926a79 DH	273
248f219c DH	274	now = jiffies;
248f219c DH	275	if (time_after_eq(now, call->expire_at)) {
5a42976d	276	rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
248f219c	277	set_bit(RXRPC_CALL_EV_ABORT, &call->events);
17926a79 DH	278	}
17926a79 DH	279
248f219c DH	280	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) \|\|
	281	time_after_eq(now, call->ack_at)) {
	282	call->ack_at = call->expire_at;
	283	if (call->ackr_reason) {
	284	rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
	285	goto recheck_state;
17926a79 DH	286	}
	287	}
	288
248f219c DH	289	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events) \|\|
248f219c DH	290	time_after_eq(now, call->resend_at)) {
17926a79	291	rxrpc_resend(call);
248f219c	292	goto recheck_state;
17926a79 DH	293	}
17926a79 DH	294
248f219c	295	rxrpc_set_timer(call);
17926a79 DH	296
17926a79 DH	297	/* other events may have been raised since we started checking */
248f219c	298	if (call->events && call->state < RXRPC_CALL_COMPLETE) {
8d94aa38	299	__rxrpc_queue_call(call);
248f219c	300	goto out;
17926a79 DH	301	}
17926a79 DH	302
248f219c DH	303	out_put:
	304	rxrpc_put_call(call, rxrpc_call_put);
	305	out:
17926a79	306	_leave("");
17926a79	307	}