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nuttx/net/tcp/tcp_backlog.c

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/****************************************************************************
* net/tcp/tcp_backlog.c
*
* Copyright (C) 2008-2009, 2011-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/net/netconfig.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && defined(CONFIG_NET_TCPBACKLOG)
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <queue.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/uip/uip.h>
#include <nuttx/net/uip/uip-tcp.h>
#include "uip/uip_internal.h"
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: uip_backlogcreate
*
* Description:
* Called from the listen() logic to setup the backlog as specified in the
* the listen arguments.
*
* Assumptions:
* Called from normal user code. Interrupts may be disabled.
*
****************************************************************************/
int uip_backlogcreate(FAR struct uip_conn *conn, int nblg)
{
FAR struct uip_backlog_s *bls = NULL;
FAR struct uip_blcontainer_s *blc;
uip_lock_t flags;
int size;
int offset;
int i;
nllvdbg("conn=%p nblg=%d\n", conn, nblg);
#ifdef CONFIG_DEBUG
if (!conn)
{
return -EINVAL;
}
#endif
/* Then allocate the backlog as requested */
if (nblg > 0)
{
/* Align the list of backlog structures to 32-bit boundaries. This
* may be excessive on 24-16-bit address machines; and insufficient
* on 64-bit address machines -- REVISIT
*/
offset = (sizeof(struct uip_backlog_s) + 3) & ~3;
/* Then determine the full size of the allocation include the
* uip_backlog_s, a pre-allocated array of struct uip_blcontainer_s
* and alignment padding
*/
size = offset + nblg * sizeof(struct uip_blcontainer_s);
/* Then allocate that much */
bls = (FAR struct uip_backlog_s *)kzalloc(size);
if (!bls)
{
nlldbg("Failed to allocate backlog\n");
return -ENOMEM;
}
/* Then add all of the pre-allocated containers to the free list */
blc = (FAR struct uip_blcontainer_s*)(((FAR uint8_t*)bls) + offset);
for (i = 0; i < nblg; i++)
{
sq_addfirst(&blc->bc_node, &bls->bl_free);
blc++;
}
}
/* Destroy any existing backlog (shouldn't be any) */
flags = uip_lock();
uip_backlogdestroy(conn);
/* Now install the backlog tear-off in the connection. NOTE that bls may
* actually be NULL if nblg is <= 0; In that case, we are disabling backlog
* support. Since interrupts are disabled, destroying the old backlog and
* replace it with the new is an atomic operation
*/
conn->backlog = bls;
uip_unlock(flags);
return OK;
}
/****************************************************************************
* Function: uip_backlogdestroy
*
* Description:
* (1) Called from uip_tcpfree() whenever a connection is freed.
* (2) Called from uip_backlogcreate() to destroy any old backlog
*
* NOTE: This function may re-enter uip_tcpfree when a connection that
* is freed that has pending connections.
*
* Assumptions:
* The caller has disabled interrupts so that there can be no conflict
* with ongoing, interrupt driven activity
*
****************************************************************************/
int uip_backlogdestroy(FAR struct uip_conn *conn)
{
FAR struct uip_backlog_s *blg;
FAR struct uip_blcontainer_s *blc;
FAR struct uip_conn *blconn;
nllvdbg("conn=%p\n", conn);
#ifdef CONFIG_DEBUG
if (!conn)
{
return -EINVAL;
}
#endif
/* Make sure that the connection has a backlog to be destroyed */
if (conn->backlog)
{
/* Remove the backlog structure reference from the connection */
blg = conn->backlog;
conn->backlog = NULL;
/* Handle any pending connections in the backlog */
while ((blc = (FAR struct uip_blcontainer_s*)sq_remfirst(&blg->bl_pending)) != NULL)
{
blconn = blc->bc_conn;
if (blconn)
{
/* REVISIT -- such connections really need to be gracefully closed */
blconn->blparent = NULL;
blconn->backlog = NULL;
blconn->crefs = 0;
uip_tcpfree(blconn);
}
}
/* Then free the entire backlog structure */
kfree(blg);
}
return OK;
}
/****************************************************************************
* Function: uip_backlogadd
*
* Description:
* Called uip_listen when a new connection is made with a listener socket
* but when there is no accept() in place to receive the connection. This
* function adds the new connection to the backlog.
*
* Assumptions:
* Called from the interrupt level with interrupts disabled
*
****************************************************************************/
int uip_backlogadd(FAR struct uip_conn *conn, FAR struct uip_conn *blconn)
{
FAR struct uip_backlog_s *bls;
FAR struct uip_blcontainer_s *blc;
int ret = -EINVAL;
nllvdbg("conn=%p blconn=%p\n", conn, blconn);
#ifdef CONFIG_DEBUG
if (!conn)
{
return -EINVAL;
}
#endif
bls = conn->backlog;
if (bls && blconn)
{
/* Allocate a container for the connection from the free list */
blc = (FAR struct uip_blcontainer_s *)sq_remfirst(&bls->bl_free);
if (!blc)
{
nlldbg("Failed to allocate container\n");
ret = -ENOMEM;
}
else
{
/* Save the connection reference in the container and put the
* container at the end of the pending connection list (FIFO).
*/
blc->bc_conn = blconn;
sq_addlast(&blc->bc_node, &bls->bl_pending);
ret = OK;
}
}
return ret;
}
/****************************************************************************
* Function: uip_backlogremove
*
* Description:
* Called from poll(). Before waiting for a new connection, poll will
* call this API to see if there are pending connections in the backlog.
*
* Assumptions:
* Called from normal user code, but with interrupts disabled,
*
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
bool uip_backlogavailable(FAR struct uip_conn *conn)
{
return (conn && conn->backlog && !sq_empty(&conn->backlog->bl_pending));
}
#endif
/****************************************************************************
* Function: uip_backlogremove
*
* Description:
* Called from accept(). Before waiting for a new connection, accept will
* call this API to see if there are pending connections in the backlog.
*
* Assumptions:
* Called from normal user code, but with interrupts disabled,
*
****************************************************************************/
struct uip_conn *uip_backlogremove(FAR struct uip_conn *conn)
{
FAR struct uip_backlog_s *bls;
FAR struct uip_blcontainer_s *blc;
FAR struct uip_conn *blconn = NULL;
#ifdef CONFIG_DEBUG
if (!conn)
{
return NULL;
}
#endif
bls = conn->backlog;
if (bls)
{
/* Remove the a container at the head of the pending connection list
* (FIFO)
*/
blc = (FAR struct uip_blcontainer_s *)sq_remfirst(&bls->bl_pending);
if (blc)
{
/* Extract the connection reference from the container and put
* container in the free list
*/
blconn = blc->bc_conn;
blc->bc_conn = NULL;
sq_addlast(&blc->bc_node, &bls->bl_free);
}
}
nllvdbg("conn=%p, returning %p\n", conn, blconn);
return blconn;
}
/****************************************************************************
* Function: uip_backlogdelete
*
* Description:
* Called from uip_tcpfree() when a connection is freed that this also
* retained in the pending connectino list of a listener. We simply need
* to remove the defunct connecton from the list.
*
* Assumptions:
* Called from the interrupt level with interrupts disabled
*
****************************************************************************/
int uip_backlogdelete(FAR struct uip_conn *conn, FAR struct uip_conn *blconn)
{
FAR struct uip_backlog_s *bls;
FAR struct uip_blcontainer_s *blc;
FAR struct uip_blcontainer_s *prev;
nllvdbg("conn=%p blconn=%p\n", conn, blconn);
#ifdef CONFIG_DEBUG
if (!conn)
{
return -EINVAL;
}
#endif
bls = conn->backlog;
if (bls)
{
/* Find the container hold the connection */
for (blc = (FAR struct uip_blcontainer_s *)sq_peek(&bls->bl_pending), prev = NULL;
blc;
prev = blc, blc = (FAR struct uip_blcontainer_s *)sq_next(&blc->bc_node))
{
if (blc->bc_conn == blconn)
{
if (prev)
{
/* Remove the a container from the middle of the list of
* pending connections
*/
(void)sq_remafter(&prev->bc_node, &bls->bl_pending);
}
else
{
/* Remove the a container from the head of the list of
* pending connections
*/
(void)sq_remfirst(&bls->bl_pending);
}
/* Put container in the free list */
blc->bc_conn = NULL;
sq_addlast(&blc->bc_node, &bls->bl_free);
return OK;
}
}
nlldbg("Failed to find pending connection\n");
return -EINVAL;
}
return OK;
}
#endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCPBACKLOG */
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