d74ca3ab82
The tcp_backlog is used when there is not process running to accept a new connection, but it is limited by the number of allocated backlog containers. The current error message induces the user to believe there is not free memory to allocate a new container, but actually the containers were allocated during the initialization and were available until the last element of the list has been removed to use.
407 lines
12 KiB
C
407 lines
12 KiB
C
/****************************************************************************
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* net/tcp/tcp_backlog.c
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*
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* Copyright (C) 2008-2009, 2011-2013, 2020 Gregory Nutt. All rights
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* reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/net/netconfig.h>
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#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && defined(CONFIG_NET_TCPBACKLOG)
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#include <stdint.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <queue.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/net/net.h>
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#include "devif/devif.h"
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#include "tcp/tcp.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tcp_backlogcreate
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*
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* Description:
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* Called from the listen() logic to setup the backlog as specified in the
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* the listen arguments.
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*
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* Assumptions:
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* Called from normal task logic. The network may or may not be locked.
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*
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****************************************************************************/
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int tcp_backlogcreate(FAR struct tcp_conn_s *conn, int nblg)
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{
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FAR struct tcp_backlog_s *bls = NULL;
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FAR struct tcp_blcontainer_s *blc;
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int size;
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int offset;
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int i;
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ninfo("conn=%p nblg=%d\n", conn, nblg);
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn)
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{
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return -EINVAL;
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}
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#endif
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/* Then allocate the backlog as requested */
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if (nblg > 0)
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{
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/* nblog value must less than SOMAXCONN */
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if (nblg > SOMAXCONN)
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{
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nblg = SOMAXCONN;
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}
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/* Align the list of backlog structures to 32-bit boundaries. This
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* may be excessive on 24-16-bit address machines; and insufficient
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* on 64-bit address machines -- REVISIT
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*/
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offset = (sizeof(struct tcp_backlog_s) + 3) & ~3;
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/* Then determine the full size of the allocation include the
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* tcp_backlog_s, a pre-allocated array of struct tcp_blcontainer_s
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* and alignment padding
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*/
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size = offset + nblg * sizeof(struct tcp_blcontainer_s);
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/* Then allocate that much */
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bls = (FAR struct tcp_backlog_s *)kmm_zalloc(size);
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if (!bls)
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{
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nerr("ERROR: Failed to allocate backlog\n");
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return -ENOMEM;
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}
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/* Then add all of the pre-allocated containers to the free list */
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blc = (FAR struct tcp_blcontainer_s *)(((FAR uint8_t *)bls) + offset);
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for (i = 0; i < nblg; i++)
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{
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sq_addfirst(&blc->bc_node, &bls->bl_free);
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blc++;
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}
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}
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/* Destroy any existing backlog (shouldn't be any) */
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net_lock();
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tcp_backlogdestroy(conn);
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/* Now install the backlog tear-off in the connection. NOTE that bls may
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* actually be NULL if nblg is <= 0; In that case, we are disabling backlog
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* support. Since the network is locked, destroying the old backlog and
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* replace it with the new is an atomic operation
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*/
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conn->backlog = bls;
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net_unlock();
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return OK;
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}
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/****************************************************************************
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* Name: tcp_backlogdestroy
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*
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* Description:
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* (1) Called from tcp_free() whenever a connection is freed.
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* (2) Called from tcp_backlogcreate() to destroy any old backlog
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*
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* NOTE: This function may re-enter tcp_free when a connection that
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* is freed that has pending connections.
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*
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* Assumptions:
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* Called from network socket logic with the network locked
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*
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****************************************************************************/
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int tcp_backlogdestroy(FAR struct tcp_conn_s *conn)
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{
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FAR struct tcp_backlog_s *blg;
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FAR struct tcp_blcontainer_s *blc;
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FAR struct tcp_conn_s *blconn;
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ninfo("conn=%p\n", conn);
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn)
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{
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return -EINVAL;
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}
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#endif
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/* Make sure that the connection has a backlog to be destroyed */
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if (conn->backlog)
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{
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/* Remove the backlog structure reference from the connection */
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blg = conn->backlog;
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conn->backlog = NULL;
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/* Handle any pending connections in the backlog */
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while ((blc = (FAR struct tcp_blcontainer_s *)
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sq_remfirst(&blg->bl_pending)) != NULL)
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{
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blconn = blc->bc_conn;
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if (blconn)
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{
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/* REVISIT -- such connections really need to be gracefully closed */
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blconn->blparent = NULL;
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blconn->backlog = NULL;
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blconn->crefs = 0;
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tcp_free(blconn);
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}
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}
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/* Then free the entire backlog structure */
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kmm_free(blg);
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}
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return OK;
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}
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/****************************************************************************
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* Name: tcp_backlogadd
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*
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* Description:
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* Called tcp_listen when a new connection is made with a listener socket
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* but when there is no accept() in place to receive the connection. This
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* function adds the new connection to the backlog.
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*
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* Assumptions:
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* Called from network socket logic with the network locked
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*
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****************************************************************************/
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int tcp_backlogadd(FAR struct tcp_conn_s *conn, FAR struct tcp_conn_s *blconn)
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{
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FAR struct tcp_backlog_s *bls;
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FAR struct tcp_blcontainer_s *blc;
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int ret = -EINVAL;
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ninfo("conn=%p blconn=%p\n", conn, blconn);
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn)
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{
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return -EINVAL;
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}
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#endif
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bls = conn->backlog;
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if (bls && blconn)
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{
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/* Get a container for the connection from the free list */
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blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&bls->bl_free);
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if (!blc)
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{
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nerr("ERROR: There are no free containers for TCP BACKLOG!\n");
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ret = -ENOMEM;
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}
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else
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{
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/* Save the connection reference in the container and put the
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* container at the end of the pending connection list (FIFO).
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*/
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blc->bc_conn = blconn;
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sq_addlast(&blc->bc_node, &bls->bl_pending);
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ret = OK;
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}
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}
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return ret;
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}
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/****************************************************************************
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* Name: tcp_backlogremove
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*
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* Description:
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* Called from poll(). Before waiting for a new connection, poll will
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* call this API to see if there are pending connections in the backlog.
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*
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* Assumptions:
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* Called from network socket logic with the network locked
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*
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****************************************************************************/
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bool tcp_backlogavailable(FAR struct tcp_conn_s *conn)
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{
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return (conn && conn->backlog && !sq_empty(&conn->backlog->bl_pending));
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}
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/****************************************************************************
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* Name: tcp_backlogremove
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*
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* Description:
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* Called from accept(). Before waiting for a new connection, accept will
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* call this API to see if there are pending connections in the backlog.
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*
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* Assumptions:
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* Called from network socket logic with the network locked
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*
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****************************************************************************/
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FAR struct tcp_conn_s *tcp_backlogremove(FAR struct tcp_conn_s *conn)
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{
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FAR struct tcp_backlog_s *bls;
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FAR struct tcp_blcontainer_s *blc;
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FAR struct tcp_conn_s *blconn = NULL;
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn)
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{
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return NULL;
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}
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#endif
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bls = conn->backlog;
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if (bls)
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{
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/* Remove the a container at the head of the pending connection list
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* (FIFO)
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*/
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blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&bls->bl_pending);
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if (blc)
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{
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/* Extract the connection reference from the container and put
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* container in the free list
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*/
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blconn = blc->bc_conn;
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blc->bc_conn = NULL;
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sq_addlast(&blc->bc_node, &bls->bl_free);
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}
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}
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ninfo("conn=%p, returning %p\n", conn, blconn);
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return blconn;
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}
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/****************************************************************************
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* Name: tcp_backlogdelete
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*
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* Description:
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* Called from tcp_free() when a connection is freed that this also
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* retained in the pending connection list of a listener. We simply need
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* to remove the defunct connection from the list.
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*
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* Assumptions:
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* Called from network socket logic with the network locked
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*
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****************************************************************************/
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int tcp_backlogdelete(FAR struct tcp_conn_s *conn,
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FAR struct tcp_conn_s *blconn)
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{
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FAR struct tcp_backlog_s *bls;
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FAR struct tcp_blcontainer_s *blc;
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FAR struct tcp_blcontainer_s *prev;
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ninfo("conn=%p blconn=%p\n", conn, blconn);
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn)
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{
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return -EINVAL;
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}
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#endif
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bls = conn->backlog;
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if (bls)
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{
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/* Find the container hold the connection */
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for (blc = (FAR struct tcp_blcontainer_s *)sq_peek(&bls->bl_pending),
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prev = NULL;
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blc;
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prev = blc, blc = (FAR struct tcp_blcontainer_s *)sq_next(&blc->bc_node))
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{
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if (blc->bc_conn == blconn)
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{
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if (prev)
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{
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/* Remove the a container from the middle of the list of
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* pending connections
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*/
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sq_remafter(&prev->bc_node, &bls->bl_pending);
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}
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else
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{
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/* Remove the a container from the head of the list of
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* pending connections
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*/
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sq_remfirst(&bls->bl_pending);
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}
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/* Put container in the free list */
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blc->bc_conn = NULL;
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sq_addlast(&blc->bc_node, &bls->bl_free);
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return OK;
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}
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}
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nerr("ERROR: Failed to find pending connection\n");
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return -EINVAL;
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}
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return OK;
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}
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#endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCPBACKLOG */
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