/* 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);
