[deliverable/linux.git] / net / rxrpc / ar-skbuff.c

/* ar-skbuff.c: socket buffer destruction handling
 *
 * 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.
 */

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

/*
 * set up for the ACK at the end of the receive phase when we discard the final
 * receive phase data packet
 * - called with softirqs disabled
 */
static void rxrpc_request_final_ACK(struct rxrpc_call *call)
{
	/* the call may be aborted before we have a chance to ACK it */
	write_lock(&call->state_lock);

	switch (call->state) {
	case RXRPC_CALL_CLIENT_RECV_REPLY:
		call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
		_debug("request final ACK");

		/* get an extra ref on the call for the final-ACK generator to
		 * release */
		rxrpc_get_call(call);
		set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
		if (try_to_del_timer_sync(&call->ack_timer) >= 0)
			rxrpc_queue_call(call);
		break;

	case RXRPC_CALL_SERVER_RECV_REQUEST:
		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
	default:
		break;
	}

	write_unlock(&call->state_lock);
}

/*
 * drop the bottom ACK off of the call ACK window and advance the window
 */
static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
				struct rxrpc_skb_priv *sp)
{
	int loop;
	u32 seq;

	spin_lock_bh(&call->lock);

	_debug("hard ACK #%u", ntohl(sp->hdr.seq));

	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
		call->ackr_window[loop] >>= 1;
		call->ackr_window[loop] |=
			call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
	}

	seq = ntohl(sp->hdr.seq);
	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
	call->rx_data_eaten = seq;

	if (call->ackr_win_top < UINT_MAX)
		call->ackr_win_top++;

	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
		    call->rx_data_post, >=, call->rx_data_recv);
	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
		    call->rx_data_recv, >=, call->rx_data_eaten);

	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
		rxrpc_request_final_ACK(call);
	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
		   test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
		/* We previously soft-ACK'd some received packets that have now
		 * been consumed, so send a hard-ACK if no more packets are
		 * immediately forthcoming to allow the transmitter to free up
		 * its Tx bufferage.
		 */
		_debug("send Rx idle ACK");
		__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
				    false);
	}

	spin_unlock_bh(&call->lock);
}

/*
 * destroy a packet that has an RxRPC control buffer
 * - advance the hard-ACK state of the parent call (done here in case something
 *   in the kernel bypasses recvmsg() and steals the packet directly off of the
 *   socket receive queue)
 */
void rxrpc_packet_destructor(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct rxrpc_call *call = sp->call;

	_enter("%p{%p}", skb, call);

	if (call) {
		/* send the final ACK on a client call */
		if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
			rxrpc_hard_ACK_data(call, sp);
		rxrpc_put_call(call);
		sp->call = NULL;
	}

	if (skb->sk)
		sock_rfree(skb);
	_leave("");
}

/**
 * rxrpc_kernel_free_skb - Free an RxRPC socket buffer
 * @skb: The socket buffer to be freed
 *
 * Let RxRPC free its own socket buffer, permitting it to maintain debug
 * accounting.
 */
void rxrpc_kernel_free_skb(struct sk_buff *skb)
{
	rxrpc_free_skb(skb);
}

EXPORT_SYMBOL(rxrpc_kernel_free_skb);
Commit	Line	Data
17926a79 DH	1	/* ar-skbuff.c: socket buffer destruction handling
	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
	12	#include <linux/module.h>
	13	#include <linux/net.h>
	14	#include <linux/skbuff.h>
	15	#include <net/sock.h>
	16	#include <net/af_rxrpc.h>
	17	#include "ar-internal.h"
	18
	19	/*
	20	* set up for the ACK at the end of the receive phase when we discard the final
	21	* receive phase data packet
	22	* - called with softirqs disabled
	23	*/
	24	static void rxrpc_request_final_ACK(struct rxrpc_call *call)
	25	{
	26	/* the call may be aborted before we have a chance to ACK it */
	27	write_lock(&call->state_lock);
	28
	29	switch (call->state) {
	30	case RXRPC_CALL_CLIENT_RECV_REPLY:
	31	call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
	32	_debug("request final ACK");
	33
	34	/* get an extra ref on the call for the final-ACK generator to
	35	* release */
	36	rxrpc_get_call(call);
	37	set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
	38	if (try_to_del_timer_sync(&call->ack_timer) >= 0)
651350d1	39	rxrpc_queue_call(call);
17926a79 DH	40	break;
	41
	42	case RXRPC_CALL_SERVER_RECV_REQUEST:
	43	call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
	44	default:
	45	break;
	46	}
	47
	48	write_unlock(&call->state_lock);
	49	}
	50
	51	/*
	52	* drop the bottom ACK off of the call ACK window and advance the window
	53	*/
	54	static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
	55	struct rxrpc_skb_priv *sp)
	56	{
	57	int loop;
	58	u32 seq;
	59
	60	spin_lock_bh(&call->lock);
	61
	62	_debug("hard ACK #%u", ntohl(sp->hdr.seq));
	63
	64	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
	65	call->ackr_window[loop] >>= 1;
	66	call->ackr_window[loop] \|=
	67	call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
	68	}
	69
	70	seq = ntohl(sp->hdr.seq);
	71	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
	72	call->rx_data_eaten = seq;
	73
	74	if (call->ackr_win_top < UINT_MAX)
	75	call->ackr_win_top++;
	76
	77	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
	78	call->rx_data_post, >=, call->rx_data_recv);
	79	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
	80	call->rx_data_recv, >=, call->rx_data_eaten);
	81
	82	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
	83	rxrpc_request_final_ACK(call);
	84	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
	85	test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
5873c083 DH	86	/* We previously soft-ACK'd some received packets that have now
	87	* been consumed, so send a hard-ACK if no more packets are
	88	* immediately forthcoming to allow the transmitter to free up
	89	* its Tx bufferage.
	90	*/
17926a79 DH	91	_debug("send Rx idle ACK");
17926a79 DH	92	__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
9823f39a	93	false);
17926a79 DH	94	}
	95
	96	spin_unlock_bh(&call->lock);
	97	}
	98
	99	/*
	100	* destroy a packet that has an RxRPC control buffer
	101	* - advance the hard-ACK state of the parent call (done here in case something
	102	* in the kernel bypasses recvmsg() and steals the packet directly off of the
	103	* socket receive queue)
	104	*/
	105	void rxrpc_packet_destructor(struct sk_buff *skb)
	106	{
	107	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	108	struct rxrpc_call *call = sp->call;
	109
	110	_enter("%p{%p}", skb, call);
	111
	112	if (call) {
	113	/* send the final ACK on a client call */
	114	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
	115	rxrpc_hard_ACK_data(call, sp);
	116	rxrpc_put_call(call);
	117	sp->call = NULL;
	118	}
	119
	120	if (skb->sk)
	121	sock_rfree(skb);
	122	_leave("");
	123	}
651350d1 DH	124
	125	/**
	126	* rxrpc_kernel_free_skb - Free an RxRPC socket buffer
	127	* @skb: The socket buffer to be freed
	128	*
	129	* Let RxRPC free its own socket buffer, permitting it to maintain debug
	130	* accounting.
	131	*/
	132	void rxrpc_kernel_free_skb(struct sk_buff *skb)
	133	{
	134	rxrpc_free_skb(skb);
	135	}
	136
	137	EXPORT_SYMBOL(rxrpc_kernel_free_skb);