call_event.c 32.2 KB
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/* 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.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

/*
 * propose an ACK be sent
 */
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void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
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			 u32 serial, bool immediate)
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{
	unsigned long expiry;
	s8 prior = rxrpc_ack_priority[ack_reason];

	ASSERTCMP(prior, >, 0);

	_enter("{%d},%s,%%%x,%u",
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	       call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
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	if (prior < rxrpc_ack_priority[call->ackr_reason]) {
		if (immediate)
			goto cancel_timer;
		return;
	}

	/* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	 * numbers */
	if (prior == rxrpc_ack_priority[call->ackr_reason]) {
		if (prior <= 4)
			call->ackr_serial = serial;
		if (immediate)
			goto cancel_timer;
		return;
	}

	call->ackr_reason = ack_reason;
	call->ackr_serial = serial;

	switch (ack_reason) {
	case RXRPC_ACK_DELAY:
		_debug("run delay timer");
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		expiry = rxrpc_soft_ack_delay;
		goto run_timer;
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	case RXRPC_ACK_IDLE:
		if (!immediate) {
			_debug("run defer timer");
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			expiry = rxrpc_idle_ack_delay;
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			goto run_timer;
		}
		goto cancel_timer;

	case RXRPC_ACK_REQUESTED:
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		expiry = rxrpc_requested_ack_delay;
		if (!expiry)
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			goto cancel_timer;
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		if (!immediate || serial == 1) {
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			_debug("run defer timer");
			goto run_timer;
		}

	default:
		_debug("immediate ACK");
		goto cancel_timer;
	}

run_timer:
	expiry += jiffies;
	if (!timer_pending(&call->ack_timer) ||
	    time_after(call->ack_timer.expires, expiry))
		mod_timer(&call->ack_timer, expiry);
	return;

cancel_timer:
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	_debug("cancel timer %%%u", serial);
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	try_to_del_timer_sync(&call->ack_timer);
	read_lock_bh(&call->state_lock);
	if (call->state <= RXRPC_CALL_COMPLETE &&
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	    !test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events))
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		rxrpc_queue_call(call);
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	read_unlock_bh(&call->state_lock);
}

/*
 * propose an ACK be sent, locking the call structure
 */
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void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
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		       u32 serial, bool immediate)
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{
	s8 prior = rxrpc_ack_priority[ack_reason];

	if (prior > rxrpc_ack_priority[call->ackr_reason]) {
		spin_lock_bh(&call->lock);
		__rxrpc_propose_ACK(call, ack_reason, serial, immediate);
		spin_unlock_bh(&call->lock);
	}
}

/*
 * set the resend timer
 */
static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
			     unsigned long resend_at)
{
	read_lock_bh(&call->state_lock);
	if (call->state >= RXRPC_CALL_COMPLETE)
		resend = 0;

	if (resend & 1) {
		_debug("SET RESEND");
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		set_bit(RXRPC_CALL_EV_RESEND, &call->events);
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	}

	if (resend & 2) {
		_debug("MODIFY RESEND TIMER");
		set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
		mod_timer(&call->resend_timer, resend_at);
	} else {
		_debug("KILL RESEND TIMER");
		del_timer_sync(&call->resend_timer);
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		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
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		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
	}
	read_unlock_bh(&call->state_lock);
}

/*
 * resend packets
 */
static void rxrpc_resend(struct rxrpc_call *call)
{
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	struct rxrpc_wire_header *whdr;
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	struct rxrpc_skb_priv *sp;
	struct sk_buff *txb;
	unsigned long *p_txb, resend_at;
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	bool stop;
	int loop;
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	u8 resend;

	_enter("{%d,%d,%d,%d},",
	       call->acks_hard, call->acks_unacked,
	       atomic_read(&call->sequence),
	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));

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	stop = false;
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	resend = 0;
	resend_at = 0;

	for (loop = call->acks_tail;
	     loop != call->acks_head || stop;
	     loop = (loop + 1) &  (call->acks_winsz - 1)
	     ) {
		p_txb = call->acks_window + loop;
		smp_read_barrier_depends();
		if (*p_txb & 1)
			continue;

		txb = (struct sk_buff *) *p_txb;
		sp = rxrpc_skb(txb);

		if (sp->need_resend) {
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			sp->need_resend = false;
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			/* each Tx packet has a new serial number */
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			sp->hdr.serial = atomic_inc_return(&call->conn->serial);
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			whdr = (struct rxrpc_wire_header *)txb->head;
			whdr->serial = htonl(sp->hdr.serial);
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			_proto("Tx DATA %%%u { #%d }",
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			       sp->hdr.serial, sp->hdr.seq);
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			if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
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				stop = true;
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				sp->resend_at = jiffies + 3;
			} else {
				sp->resend_at =
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					jiffies + rxrpc_resend_timeout;
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			}
		}

		if (time_after_eq(jiffies + 1, sp->resend_at)) {
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			sp->need_resend = true;
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			resend |= 1;
		} else if (resend & 2) {
			if (time_before(sp->resend_at, resend_at))
				resend_at = sp->resend_at;
		} else {
			resend_at = sp->resend_at;
			resend |= 2;
		}
	}

	rxrpc_set_resend(call, resend, resend_at);
	_leave("");
}

/*
 * handle resend timer expiry
 */
static void rxrpc_resend_timer(struct rxrpc_call *call)
{
	struct rxrpc_skb_priv *sp;
	struct sk_buff *txb;
	unsigned long *p_txb, resend_at;
	int loop;
	u8 resend;

	_enter("%d,%d,%d",
	       call->acks_tail, call->acks_unacked, call->acks_head);

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	if (call->state >= RXRPC_CALL_COMPLETE)
		return;

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	resend = 0;
	resend_at = 0;

	for (loop = call->acks_unacked;
	     loop != call->acks_head;
	     loop = (loop + 1) &  (call->acks_winsz - 1)
	     ) {
		p_txb = call->acks_window + loop;
		smp_read_barrier_depends();
		txb = (struct sk_buff *) (*p_txb & ~1);
		sp = rxrpc_skb(txb);

		ASSERT(!(*p_txb & 1));

		if (sp->need_resend) {
			;
		} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
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			sp->need_resend = true;
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			resend |= 1;
		} else if (resend & 2) {
			if (time_before(sp->resend_at, resend_at))
				resend_at = sp->resend_at;
		} else {
			resend_at = sp->resend_at;
			resend |= 2;
		}
	}

	rxrpc_set_resend(call, resend, resend_at);
	_leave("");
}

/*
 * process soft ACKs of our transmitted packets
 * - these indicate packets the peer has or has not received, but hasn't yet
 *   given to the consumer, and so can still be discarded and re-requested
 */
static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
				   struct rxrpc_ackpacket *ack,
				   struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp;
	struct sk_buff *txb;
	unsigned long *p_txb, resend_at;
	int loop;
	u8 sacks[RXRPC_MAXACKS], resend;

	_enter("{%d,%d},{%d},",
	       call->acks_hard,
	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
	       ack->nAcks);

	if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
		goto protocol_error;

	resend = 0;
	resend_at = 0;
	for (loop = 0; loop < ack->nAcks; loop++) {
		p_txb = call->acks_window;
		p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
		smp_read_barrier_depends();
		txb = (struct sk_buff *) (*p_txb & ~1);
		sp = rxrpc_skb(txb);

		switch (sacks[loop]) {
		case RXRPC_ACK_TYPE_ACK:
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			sp->need_resend = false;
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			*p_txb |= 1;
			break;
		case RXRPC_ACK_TYPE_NACK:
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			sp->need_resend = true;
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			*p_txb &= ~1;
			resend = 1;
			break;
		default:
			_debug("Unsupported ACK type %d", sacks[loop]);
			goto protocol_error;
		}
	}

	smp_mb();
	call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);

	/* anything not explicitly ACK'd is implicitly NACK'd, but may just not
	 * have been received or processed yet by the far end */
	for (loop = call->acks_unacked;
	     loop != call->acks_head;
	     loop = (loop + 1) &  (call->acks_winsz - 1)
	     ) {
		p_txb = call->acks_window + loop;
		smp_read_barrier_depends();
		txb = (struct sk_buff *) (*p_txb & ~1);
		sp = rxrpc_skb(txb);

		if (*p_txb & 1) {
			/* packet must have been discarded */
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			sp->need_resend = true;
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			*p_txb &= ~1;
			resend |= 1;
		} else if (sp->need_resend) {
			;
		} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
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			sp->need_resend = true;
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			resend |= 1;
		} else if (resend & 2) {
			if (time_before(sp->resend_at, resend_at))
				resend_at = sp->resend_at;
		} else {
			resend_at = sp->resend_at;
			resend |= 2;
		}
	}

	rxrpc_set_resend(call, resend, resend_at);
	_leave(" = 0");
	return 0;

protocol_error:
	_leave(" = -EPROTO");
	return -EPROTO;
}

/*
 * discard hard-ACK'd packets from the Tx window
 */
static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
{
	unsigned long _skb;
	int tail = call->acks_tail, old_tail;
	int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);

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	_enter("{%u,%u},%u", call->acks_hard, win, hard);
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	ASSERTCMP(hard - call->acks_hard, <=, win);

	while (call->acks_hard < hard) {
		smp_read_barrier_depends();
		_skb = call->acks_window[tail] & ~1;
		rxrpc_free_skb((struct sk_buff *) _skb);
		old_tail = tail;
		tail = (tail + 1) & (call->acks_winsz - 1);
		call->acks_tail = tail;
		if (call->acks_unacked == old_tail)
			call->acks_unacked = tail;
		call->acks_hard++;
	}

	wake_up(&call->tx_waitq);
}

/*
 * clear the Tx window in the event of a failure
 */
static void rxrpc_clear_tx_window(struct rxrpc_call *call)
{
	rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
}

/*
 * drain the out of sequence received packet queue into the packet Rx queue
 */
static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
{
	struct rxrpc_skb_priv *sp;
	struct sk_buff *skb;
	bool terminal;
	int ret;

	_enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);

	spin_lock_bh(&call->lock);

	ret = -ECONNRESET;
	if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
		goto socket_unavailable;

	skb = skb_dequeue(&call->rx_oos_queue);
	if (skb) {
		sp = rxrpc_skb(skb);

		_debug("drain OOS packet %d [%d]",
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		       sp->hdr.seq, call->rx_first_oos);
414

415
		if (sp->hdr.seq != call->rx_first_oos) {
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			skb_queue_head(&call->rx_oos_queue, skb);
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			call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
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			_debug("requeue %p {%u}", skb, call->rx_first_oos);
		} else {
			skb->mark = RXRPC_SKB_MARK_DATA;
			terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
				!(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
			ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
			BUG_ON(ret < 0);
			_debug("drain #%u", call->rx_data_post);
			call->rx_data_post++;

			/* find out what the next packet is */
			skb = skb_peek(&call->rx_oos_queue);
			if (skb)
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				call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
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			else
				call->rx_first_oos = 0;
			_debug("peek %p {%u}", skb, call->rx_first_oos);
		}
	}

	ret = 0;
socket_unavailable:
	spin_unlock_bh(&call->lock);
	_leave(" = %d", ret);
	return ret;
}

/*
 * insert an out of sequence packet into the buffer
 */
static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
				    struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp, *psp;
	struct sk_buff *p;
	u32 seq;

	sp = rxrpc_skb(skb);
456
	seq = sp->hdr.seq;
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	_enter(",,{%u}", seq);

	skb->destructor = rxrpc_packet_destructor;
	ASSERTCMP(sp->call, ==, NULL);
	sp->call = call;
	rxrpc_get_call(call);

	/* insert into the buffer in sequence order */
	spin_lock_bh(&call->lock);

	skb_queue_walk(&call->rx_oos_queue, p) {
		psp = rxrpc_skb(p);
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		if (psp->hdr.seq > seq) {
			_debug("insert oos #%u before #%u", seq, psp->hdr.seq);
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			skb_insert(p, skb, &call->rx_oos_queue);
			goto inserted;
		}
	}

	_debug("append oos #%u", seq);
	skb_queue_tail(&call->rx_oos_queue, skb);
inserted:

	/* we might now have a new front to the queue */
	if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
		call->rx_first_oos = seq;

	read_lock(&call->state_lock);
	if (call->state < RXRPC_CALL_COMPLETE &&
	    call->rx_data_post == call->rx_first_oos) {
		_debug("drain rx oos now");
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		set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
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	}
	read_unlock(&call->state_lock);

	spin_unlock_bh(&call->lock);
	_leave(" [stored #%u]", call->rx_first_oos);
}

/*
 * clear the Tx window on final ACK reception
 */
static void rxrpc_zap_tx_window(struct rxrpc_call *call)
{
	struct rxrpc_skb_priv *sp;
	struct sk_buff *skb;
	unsigned long _skb, *acks_window;
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	u8 winsz = call->acks_winsz;
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	int tail;

	acks_window = call->acks_window;
	call->acks_window = NULL;

	while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
		tail = call->acks_tail;
		smp_read_barrier_depends();
		_skb = acks_window[tail] & ~1;
		smp_mb();
		call->acks_tail = (call->acks_tail + 1) & (winsz - 1);

		skb = (struct sk_buff *) _skb;
		sp = rxrpc_skb(skb);
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		_debug("+++ clear Tx %u", sp->hdr.seq);
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		rxrpc_free_skb(skb);
	}

	kfree(acks_window);
}

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/*
 * process the extra information that may be appended to an ACK packet
 */
static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
530
				  unsigned int latest, int nAcks)
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{
	struct rxrpc_ackinfo ackinfo;
	struct rxrpc_peer *peer;
534
	unsigned int mtu;
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	if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
		_leave(" [no ackinfo]");
		return;
	}

	_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
	       latest,
	       ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
	       ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));

	mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));

	peer = call->conn->trans->peer;
	if (mtu < peer->maxdata) {
		spin_lock_bh(&peer->lock);
		peer->maxdata = mtu;
		peer->mtu = mtu + peer->hdrsize;
		spin_unlock_bh(&peer->lock);
		_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
	}
}

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/*
 * process packets in the reception queue
 */
static int rxrpc_process_rx_queue(struct rxrpc_call *call,
				  u32 *_abort_code)
{
	struct rxrpc_ackpacket ack;
	struct rxrpc_skb_priv *sp;
	struct sk_buff *skb;
	bool post_ACK;
	int latest;
	u32 hard, tx;

	_enter("");

process_further:
	skb = skb_dequeue(&call->rx_queue);
	if (!skb)
		return -EAGAIN;

	_net("deferred skb %p", skb);

	sp = rxrpc_skb(skb);

	_debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);

	post_ACK = false;

	switch (sp->hdr.type) {
		/* data packets that wind up here have been received out of
		 * order, need security processing or are jumbo packets */
	case RXRPC_PACKET_TYPE_DATA:
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		_proto("OOSQ DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
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		/* secured packets must be verified and possibly decrypted */
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		if (call->conn->security->verify_packet(call, skb,
							_abort_code) < 0)
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			goto protocol_error;

		rxrpc_insert_oos_packet(call, skb);
		goto process_further;

		/* partial ACK to process */
	case RXRPC_PACKET_TYPE_ACK:
		if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
			_debug("extraction failure");
			goto protocol_error;
		}
		if (!skb_pull(skb, sizeof(ack)))
			BUG();

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		latest = sp->hdr.serial;
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		hard = ntohl(ack.firstPacket);
		tx = atomic_read(&call->sequence);

		_proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
		       latest,
		       ntohs(ack.maxSkew),
		       hard,
		       ntohl(ack.previousPacket),
		       ntohl(ack.serial),
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		       rxrpc_acks(ack.reason),
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		       ack.nAcks);

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		rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);

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		if (ack.reason == RXRPC_ACK_PING) {
			_proto("Rx ACK %%%u PING Request", latest);
			rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
					  sp->hdr.serial, true);
		}

		/* discard any out-of-order or duplicate ACKs */
		if (latest - call->acks_latest <= 0) {
			_debug("discard ACK %d <= %d",
			       latest, call->acks_latest);
			goto discard;
		}
		call->acks_latest = latest;

		if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
		    call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
		    call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
		    call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
			goto discard;

		_debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);

		if (hard > 0) {
			if (hard - 1 > tx) {
				_debug("hard-ACK'd packet %d not transmitted"
				       " (%d top)",
				       hard - 1, tx);
				goto protocol_error;
			}

			if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
			     call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
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			    hard > tx) {
				call->acks_hard = tx;
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				goto all_acked;
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			}
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			smp_rmb();
			rxrpc_rotate_tx_window(call, hard - 1);
		}

		if (ack.nAcks > 0) {
			if (hard - 1 + ack.nAcks > tx) {
				_debug("soft-ACK'd packet %d+%d not"
				       " transmitted (%d top)",
				       hard - 1, ack.nAcks, tx);
				goto protocol_error;
			}

			if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
				goto protocol_error;
		}
		goto discard;

		/* complete ACK to process */
	case RXRPC_PACKET_TYPE_ACKALL:
		goto all_acked;

		/* abort and busy are handled elsewhere */
	case RXRPC_PACKET_TYPE_BUSY:
	case RXRPC_PACKET_TYPE_ABORT:
		BUG();

		/* connection level events - also handled elsewhere */
	case RXRPC_PACKET_TYPE_CHALLENGE:
	case RXRPC_PACKET_TYPE_RESPONSE:
	case RXRPC_PACKET_TYPE_DEBUG:
		BUG();
	}

	/* if we've had a hard ACK that covers all the packets we've sent, then
	 * that ends that phase of the operation */
all_acked:
	write_lock_bh(&call->state_lock);
	_debug("ack all %d", call->state);

	switch (call->state) {
	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
		call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
		break;
	case RXRPC_CALL_SERVER_AWAIT_ACK:
		_debug("srv complete");
		call->state = RXRPC_CALL_COMPLETE;
		post_ACK = true;
		break;
	case RXRPC_CALL_CLIENT_SEND_REQUEST:
	case RXRPC_CALL_SERVER_RECV_REQUEST:
		goto protocol_error_unlock; /* can't occur yet */
	default:
		write_unlock_bh(&call->state_lock);
		goto discard; /* assume packet left over from earlier phase */
	}

	write_unlock_bh(&call->state_lock);

	/* if all the packets we sent are hard-ACK'd, then we can discard
	 * whatever we've got left */
	_debug("clear Tx %d",
	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));

	del_timer_sync(&call->resend_timer);
	clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
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	clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
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	if (call->acks_window)
		rxrpc_zap_tx_window(call);

	if (post_ACK) {
		/* post the final ACK message for userspace to pick up */
		_debug("post ACK");
		skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
		sp->call = call;
		rxrpc_get_call(call);
		spin_lock_bh(&call->lock);
		if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
			BUG();
		spin_unlock_bh(&call->lock);
		goto process_further;
	}

discard:
	rxrpc_free_skb(skb);
	goto process_further;

protocol_error_unlock:
	write_unlock_bh(&call->state_lock);
protocol_error:
	rxrpc_free_skb(skb);
	_leave(" = -EPROTO");
	return -EPROTO;
}

/*
 * post a message to the socket Rx queue for recvmsg() to pick up
 */
static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
			      bool fatal)
{
	struct rxrpc_skb_priv *sp;
	struct sk_buff *skb;
	int ret;

	_enter("{%d,%lx},%u,%u,%d",
	       call->debug_id, call->flags, mark, error, fatal);

	/* remove timers and things for fatal messages */
	if (fatal) {
		del_timer_sync(&call->resend_timer);
		del_timer_sync(&call->ack_timer);
		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
	}

	if (mark != RXRPC_SKB_MARK_NEW_CALL &&
	    !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
		_leave("[no userid]");
		return 0;
	}

	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
		skb = alloc_skb(0, GFP_NOFS);
		if (!skb)
			return -ENOMEM;

		rxrpc_new_skb(skb);

		skb->mark = mark;

		sp = rxrpc_skb(skb);
		memset(sp, 0, sizeof(*sp));
		sp->error = error;
		sp->call = call;
		rxrpc_get_call(call);

		spin_lock_bh(&call->lock);
		ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
		spin_unlock_bh(&call->lock);
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Julia Lawall committed
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		BUG_ON(ret < 0);
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	}

	return 0;
}

/*
 * handle background processing of incoming call packets and ACK / abort
 * generation
 */
void rxrpc_process_call(struct work_struct *work)
{
	struct rxrpc_call *call =
		container_of(work, struct rxrpc_call, processor);
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	struct rxrpc_wire_header whdr;
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	struct rxrpc_ackpacket ack;
	struct rxrpc_ackinfo ackinfo;
	struct msghdr msg;
	struct kvec iov[5];
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	enum rxrpc_call_event genbit;
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	unsigned long bits;
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	__be32 data, pad;
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	size_t len;
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	int loop, nbit, ioc, ret, mtu;
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	u32 serial, abort_code = RX_PROTOCOL_ERROR;
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	u8 *acks = NULL;

	//printk("\n--------------------\n");
	_enter("{%d,%s,%lx} [%lu]",
	       call->debug_id, rxrpc_call_states[call->state], call->events,
	       (jiffies - call->creation_jif) / (HZ / 10));

	if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
		_debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
		return;
	}

	/* there's a good chance we're going to have to send a message, so set
	 * one up in advance */
839 840
	msg.msg_name	= &call->conn->trans->peer->srx.transport;
	msg.msg_namelen	= call->conn->trans->peer->srx.transport_len;
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	msg.msg_control	= NULL;
	msg.msg_controllen = 0;
	msg.msg_flags	= 0;

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	whdr.epoch	= htonl(call->conn->epoch);
	whdr.cid	= htonl(call->cid);
	whdr.callNumber	= htonl(call->call_id);
	whdr.seq	= 0;
	whdr.type	= RXRPC_PACKET_TYPE_ACK;
	whdr.flags	= call->conn->out_clientflag;
	whdr.userStatus	= 0;
	whdr.securityIndex = call->conn->security_ix;
	whdr._rsvd	= 0;
	whdr.serviceId	= htons(call->service_id);
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	memset(iov, 0, sizeof(iov));
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	iov[0].iov_base	= &whdr;
	iov[0].iov_len	= sizeof(whdr);
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	/* deal with events of a final nature */
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	if (test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
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		rxrpc_release_call(call);
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		clear_bit(RXRPC_CALL_EV_RELEASE, &call->events);
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	}

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	if (test_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events)) {
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		int error;

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		clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
		clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
		clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
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		error = call->conn->trans->peer->net_error;
		_debug("post net error %d", error);

		if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
				       error, true) < 0)
			goto no_mem;
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		clear_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
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		goto kill_ACKs;
	}

883
	if (test_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events)) {
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		ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);

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		clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
		clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
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		_debug("post conn abort");

		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
				       call->conn->error, true) < 0)
			goto no_mem;
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		clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
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		goto kill_ACKs;
	}

898
	if (test_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events)) {
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		whdr.type = RXRPC_PACKET_TYPE_BUSY;
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		genbit = RXRPC_CALL_EV_REJECT_BUSY;
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		goto send_message;
	}

904
	if (test_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
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		ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);

		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
				       ECONNABORTED, true) < 0)
			goto no_mem;
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		whdr.type = RXRPC_PACKET_TYPE_ABORT;
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		data = htonl(call->local_abort);
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		iov[1].iov_base = &data;
		iov[1].iov_len = sizeof(data);
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		genbit = RXRPC_CALL_EV_ABORT;
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		goto send_message;
	}

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	if (test_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events)) {
		genbit = RXRPC_CALL_EV_ACK_FINAL;
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		ack.bufferSpace	= htons(8);
		ack.maxSkew	= 0;
		ack.serial	= 0;
		ack.reason	= RXRPC_ACK_IDLE;
		ack.nAcks	= 0;
		call->ackr_reason = 0;

		spin_lock_bh(&call->lock);
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		ack.serial	= htonl(call->ackr_serial);
		ack.previousPacket = htonl(call->ackr_prev_seq);
		ack.firstPacket	= htonl(call->rx_data_eaten + 1);
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		spin_unlock_bh(&call->lock);

		pad = 0;

		iov[1].iov_base = &ack;
		iov[1].iov_len	= sizeof(ack);
		iov[2].iov_base = &pad;
		iov[2].iov_len	= 3;
		iov[3].iov_base = &ackinfo;
		iov[3].iov_len	= sizeof(ackinfo);
		goto send_ACK;
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	}

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	if (call->events & ((1 << RXRPC_CALL_EV_RCVD_BUSY) |
			    (1 << RXRPC_CALL_EV_RCVD_ABORT))
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	    ) {
		u32 mark;

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		if (test_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events))
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			mark = RXRPC_SKB_MARK_REMOTE_ABORT;
		else
			mark = RXRPC_SKB_MARK_BUSY;

		_debug("post abort/busy");
		rxrpc_clear_tx_window(call);
		if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
			goto no_mem;

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		clear_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
		clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
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		goto kill_ACKs;
	}

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	if (test_and_clear_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events)) {
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		_debug("do implicit ackall");
		rxrpc_clear_tx_window(call);
	}

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	if (test_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events)) {
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		write_lock_bh(&call->state_lock);
		if (call->state <= RXRPC_CALL_COMPLETE) {
			call->state = RXRPC_CALL_LOCALLY_ABORTED;
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			call->local_abort = RX_CALL_TIMEOUT;
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			set_bit(RXRPC_CALL_EV_ABORT, &call->events);
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		}
		write_unlock_bh(&call->state_lock);

		_debug("post timeout");
		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
				       ETIME, true) < 0)
			goto no_mem;

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		clear_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events);
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		goto kill_ACKs;
	}

	/* deal with assorted inbound messages */
	if (!skb_queue_empty(&call->rx_queue)) {
		switch (rxrpc_process_rx_queue(call, &abort_code)) {
		case 0:
		case -EAGAIN:
			break;
		case -ENOMEM:
			goto no_mem;
		case -EKEYEXPIRED:
		case -EKEYREJECTED:
		case -EPROTO:
			rxrpc_abort_call(call, abort_code);
			goto kill_ACKs;
		}
	}

	/* handle resending */
1005
	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
1006
		rxrpc_resend_timer(call);
1007
	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events))
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		rxrpc_resend(call);

	/* consider sending an ordinary ACK */
1011
	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
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		_debug("send ACK: window: %d - %d { %lx }",
		       call->rx_data_eaten, call->ackr_win_top,
		       call->ackr_window[0]);

		if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
		    call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
			/* ACK by sending reply DATA packet in this state */
1019
			clear_bit(RXRPC_CALL_EV_ACK, &call->events);
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			goto maybe_reschedule;
		}

1023
		genbit = RXRPC_CALL_EV_ACK;
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		acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
			       GFP_NOFS);
		if (!acks)
			goto no_mem;

		//hdr.flags	= RXRPC_SLOW_START_OK;
		ack.bufferSpace	= htons(8);
		ack.maxSkew	= 0;

		spin_lock_bh(&call->lock);
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		ack.reason	= call->ackr_reason;
		ack.serial	= htonl(call->ackr_serial);
		ack.previousPacket = htonl(call->ackr_prev_seq);
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		ack.firstPacket = htonl(call->rx_data_eaten + 1);

		ack.nAcks = 0;
		for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
			nbit = loop * BITS_PER_LONG;
			for (bits = call->ackr_window[loop]; bits; bits >>= 1
			     ) {
				_debug("- l=%d n=%d b=%lx", loop, nbit, bits);
				if (bits & 1) {
					acks[nbit] = RXRPC_ACK_TYPE_ACK;
					ack.nAcks = nbit + 1;
				}
				nbit++;
			}
		}
		call->ackr_reason = 0;
		spin_unlock_bh(&call->lock);

		pad = 0;

		iov[1].iov_base = &ack;
		iov[1].iov_len	= sizeof(ack);
		iov[2].iov_base = acks;
		iov[2].iov_len	= ack.nAcks;
		iov[3].iov_base = &pad;
		iov[3].iov_len	= 3;
		iov[4].iov_base = &ackinfo;
		iov[4].iov_len	= sizeof(ackinfo);

		switch (ack.reason) {
		case RXRPC_ACK_REQUESTED:
		case RXRPC_ACK_DUPLICATE:
		case RXRPC_ACK_OUT_OF_SEQUENCE:
		case RXRPC_ACK_EXCEEDS_WINDOW:
		case RXRPC_ACK_NOSPACE:
		case RXRPC_ACK_PING:
		case RXRPC_ACK_PING_RESPONSE:
			goto send_ACK_with_skew;
		case RXRPC_ACK_DELAY:
		case RXRPC_ACK_IDLE:
			goto send_ACK;
		}
	}

	/* handle completion of security negotiations on an incoming
	 * connection */
1084
	if (test_and_clear_bit(RXRPC_CALL_EV_SECURED, &call->events)) {
1085 1086 1087 1088 1089 1090 1091
		_debug("secured");
		spin_lock_bh(&call->lock);

		if (call->state == RXRPC_CALL_SERVER_SECURING) {
			_debug("securing");
			write_lock(&call->conn->lock);
			if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1092
			    !test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
1093 1094 1095 1096 1097 1098 1099 1100
				_debug("not released");
				call->state = RXRPC_CALL_SERVER_ACCEPTING;
				list_move_tail(&call->accept_link,
					       &call->socket->acceptq);
			}
			write_unlock(&call->conn->lock);
			read_lock(&call->state_lock);
			if (call->state < RXRPC_CALL_COMPLETE)
1101
				set_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
1102 1103 1104 1105
			read_unlock(&call->state_lock);
		}

		spin_unlock_bh(&call->lock);
1106
		if (!test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events))
1107 1108 1109 1110
			goto maybe_reschedule;
	}

	/* post a notification of an acceptable connection to the app */
1111
	if (test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events)) {
1112 1113 1114 1115
		_debug("post accept");
		if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
				       0, false) < 0)
			goto no_mem;
1116
		clear_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
1117 1118 1119 1120
		goto maybe_reschedule;
	}

	/* handle incoming call acceptance */
1121
	if (test_and_clear_bit(RXRPC_CALL_EV_ACCEPTED, &call->events)) {
1122 1123 1124 1125 1126
		_debug("accepted");
		ASSERTCMP(call->rx_data_post, ==, 0);
		call->rx_data_post = 1;
		read_lock_bh(&call->state_lock);
		if (call->state < RXRPC_CALL_COMPLETE)
1127
			set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
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		read_unlock_bh(&call->state_lock);
	}

	/* drain the out of sequence received packet queue into the packet Rx
	 * queue */
1133
	if (test_and_clear_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events)) {
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
		while (call->rx_data_post == call->rx_first_oos)
			if (rxrpc_drain_rx_oos_queue(call) < 0)
				break;
		goto maybe_reschedule;
	}

	/* other events may have been raised since we started checking */
	goto maybe_reschedule;

send_ACK_with_skew:
	ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
			    ntohl(ack.serial));
send_ACK:
1147 1148 1149
	mtu = call->conn->trans->peer->if_mtu;
	mtu -= call->conn->trans->peer->hdrsize;
	ackinfo.maxMTU	= htonl(mtu);
1150
	ackinfo.rwind	= htonl(rxrpc_rx_window_size);
1151 1152

	/* permit the peer to send us jumbo packets if it wants to */
1153 1154
	ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
	ackinfo.jumbo_max = htonl(rxrpc_rx_jumbo_max);
1155

1156 1157
	serial = atomic_inc_return(&call->conn->serial);
	whdr.serial = htonl(serial);
1158
	_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1159
	       serial,
1160 1161 1162 1163
	       ntohs(ack.maxSkew),
	       ntohl(ack.firstPacket),
	       ntohl(ack.previousPacket),
	       ntohl(ack.serial),
1164
	       rxrpc_acks(ack.reason),
1165 1166 1167 1168 1169 1170 1171 1172 1173 1174
	       ack.nAcks);

	del_timer_sync(&call->ack_timer);
	if (ack.nAcks > 0)
		set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
	goto send_message_2;

send_message:
	_debug("send message");

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	serial = atomic_inc_return(&call->conn->serial);
	whdr.serial = htonl(serial);
	_proto("Tx %s %%%u", rxrpc_pkts[whdr.type], serial);
1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207
send_message_2:

	len = iov[0].iov_len;
	ioc = 1;
	if (iov[4].iov_len) {
		ioc = 5;
		len += iov[4].iov_len;
		len += iov[3].iov_len;
		len += iov[2].iov_len;
		len += iov[1].iov_len;
	} else if (iov[3].iov_len) {
		ioc = 4;
		len += iov[3].iov_len;
		len += iov[2].iov_len;
		len += iov[1].iov_len;
	} else if (iov[2].iov_len) {
		ioc = 3;
		len += iov[2].iov_len;
		len += iov[1].iov_len;
	} else if (iov[1].iov_len) {
		ioc = 2;
		len += iov[1].iov_len;
	}

	ret = kernel_sendmsg(call->conn->trans->local->socket,
			     &msg, iov, ioc, len);
	if (ret < 0) {
		_debug("sendmsg failed: %d", ret);
		read_lock_bh(&call->state_lock);
		if (call->state < RXRPC_CALL_DEAD)
1208
			rxrpc_queue_call(call);
1209 1210 1211 1212 1213
		read_unlock_bh(&call->state_lock);
		goto error;
	}

	switch (genbit) {
1214
	case RXRPC_CALL_EV_ABORT:
1215
		clear_bit(genbit, &call->events);
1216
		clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
1217 1218
		goto kill_ACKs;

1219
	case RXRPC_CALL_EV_ACK_FINAL:
1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
		write_lock_bh(&call->state_lock);
		if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
			call->state = RXRPC_CALL_COMPLETE;
		write_unlock_bh(&call->state_lock);
		goto kill_ACKs;

	default:
		clear_bit(genbit, &call->events);
		switch (call->state) {
		case RXRPC_CALL_CLIENT_AWAIT_REPLY:
		case RXRPC_CALL_CLIENT_RECV_REPLY:
		case RXRPC_CALL_SERVER_RECV_REQUEST:
		case RXRPC_CALL_SERVER_ACK_REQUEST:
			_debug("start ACK timer");
			rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
					  call->ackr_serial, false);
		default:
			break;
		}
		goto maybe_reschedule;
	}

kill_ACKs:
	del_timer_sync(&call->ack_timer);
1244
	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events))
1245
		rxrpc_put_call(call);
1246
	clear_bit(RXRPC_CALL_EV_ACK, &call->events);
1247 1248 1249 1250 1251

maybe_reschedule:
	if (call->events || !skb_queue_empty(&call->rx_queue)) {
		read_lock_bh(&call->state_lock);
		if (call->state < RXRPC_CALL_DEAD)
1252
			rxrpc_queue_call(call);
1253 1254 1255 1256 1257 1258 1259
		read_unlock_bh(&call->state_lock);
	}

	/* don't leave aborted connections on the accept queue */
	if (call->state >= RXRPC_CALL_COMPLETE &&
	    !list_empty(&call->accept_link)) {
		_debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1260
		       call, call->events, call->flags, call->conn->cid);
1261 1262 1263

		read_lock_bh(&call->state_lock);
		if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1264
		    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
1265
			rxrpc_queue_call(call);
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277
		read_unlock_bh(&call->state_lock);
	}

error:
	clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
	kfree(acks);

	/* because we don't want two CPUs both processing the work item for one
	 * call at the same time, we use a flag to note when it's busy; however
	 * this means there's a race between clearing the flag and setting the
	 * work pending bit and the work item being processed again */
	if (call->events && !work_pending(&call->processor)) {
1278
		_debug("jumpstart %x", call->conn->cid);
1279
		rxrpc_queue_call(call);
1280 1281 1282 1283 1284 1285 1286 1287 1288
	}

	_leave("");
	return;

no_mem:
	_debug("out of memory");
	goto maybe_reschedule;
}