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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/net.h>
- #include "devif/devif.h"
- #include "tcp/tcp.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: tcp_backlogcreate
- *
- * Description:
- * Called from the listen() logic to setup the backlog as specified in the
- * the listen arguments.
- *
- * Assumptions:
- * Called from normal task logic. The network may or may not be locked.
- *
- ****************************************************************************/
- int tcp_backlogcreate(FAR struct tcp_conn_s *conn, int nblg)
- {
- FAR struct tcp_backlog_s *bls = NULL;
- FAR struct tcp_blcontainer_s *blc;
- int size;
- int offset;
- int i;
- ninfo("conn=%p nblg=%d\n", conn, nblg);
- #ifdef CONFIG_DEBUG_FEATURES
- if (!conn)
- {
- return -EINVAL;
- }
- #endif
- /* Then allocate the backlog as requested */
- if (nblg > 0)
- {
- /* nblog value must less than SOMAXCONN */
- if (nblg > SOMAXCONN)
- {
- nblg = SOMAXCONN;
- }
- /* 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 tcp_backlog_s) + 3) & ~3;
- /* Then determine the full size of the allocation include the
- * tcp_backlog_s, a pre-allocated array of struct tcp_blcontainer_s
- * and alignment padding
- */
- size = offset + nblg * sizeof(struct tcp_blcontainer_s);
- /* Then allocate that much */
- bls = (FAR struct tcp_backlog_s *)kmm_zalloc(size);
- if (!bls)
- {
- nerr("ERROR: Failed to allocate backlog\n");
- return -ENOMEM;
- }
- /* Then add all of the pre-allocated containers to the free list */
- blc = (FAR struct tcp_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) */
- net_lock();
- tcp_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 the network is locked, destroying the old backlog and
- * replace it with the new is an atomic operation
- */
- conn->backlog = bls;
- net_unlock();
- return OK;
- }
- /****************************************************************************
- * Name: tcp_backlogdestroy
- *
- * Description:
- * (1) Called from tcp_free() whenever a connection is freed.
- * (2) Called from tcp_backlogcreate() to destroy any old backlog
- *
- * NOTE: This function may re-enter tcp_free when a connection that
- * is freed that has pending connections.
- *
- * Assumptions:
- * Called from network socket logic with the network locked
- *
- ****************************************************************************/
- int tcp_backlogdestroy(FAR struct tcp_conn_s *conn)
- {
- FAR struct tcp_backlog_s *blg;
- FAR struct tcp_blcontainer_s *blc;
- FAR struct tcp_conn_s *blconn;
- ninfo("conn=%p\n", conn);
- #ifdef CONFIG_DEBUG_FEATURES
- 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 tcp_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;
- tcp_free(blconn);
- }
- }
- /* Then free the entire backlog structure */
- kmm_free(blg);
- }
- return OK;
- }
- /****************************************************************************
- * Name: tcp_backlogadd
- *
- * Description:
- * Called tcp_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 network socket logic with the network locked
- *
- ****************************************************************************/
- int tcp_backlogadd(FAR struct tcp_conn_s *conn, FAR struct tcp_conn_s *blconn)
- {
- FAR struct tcp_backlog_s *bls;
- FAR struct tcp_blcontainer_s *blc;
- int ret = -EINVAL;
- ninfo("conn=%p blconn=%p\n", conn, blconn);
- #ifdef CONFIG_DEBUG_FEATURES
- if (!conn)
- {
- return -EINVAL;
- }
- #endif
- bls = conn->backlog;
- if (bls && blconn)
- {
- /* Allocate a container for the connection from the free list */
- blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&bls->bl_free);
- if (!blc)
- {
- nerr("ERROR: 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;
- }
- /****************************************************************************
- * Name: tcp_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 network socket logic with the network locked
- *
- ****************************************************************************/
- bool tcp_backlogavailable(FAR struct tcp_conn_s *conn)
- {
- return (conn && conn->backlog && !sq_empty(&conn->backlog->bl_pending));
- }
- /****************************************************************************
- * Name: tcp_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 network socket logic with the network locked
- *
- ****************************************************************************/
- FAR struct tcp_conn_s *tcp_backlogremove(FAR struct tcp_conn_s *conn)
- {
- FAR struct tcp_backlog_s *bls;
- FAR struct tcp_blcontainer_s *blc;
- FAR struct tcp_conn_s *blconn = NULL;
- #ifdef CONFIG_DEBUG_FEATURES
- 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 tcp_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);
- }
- }
- ninfo("conn=%p, returning %p\n", conn, blconn);
- return blconn;
- }
- /****************************************************************************
- * Name: tcp_backlogdelete
- *
- * Description:
- * Called from tcp_free() when a connection is freed that this also
- * retained in the pending connection list of a listener. We simply need
- * to remove the defunct connection from the list.
- *
- * Assumptions:
- * Called from network socket logic with the network locked
- *
- ****************************************************************************/
- int tcp_backlogdelete(FAR struct tcp_conn_s *conn,
- FAR struct tcp_conn_s *blconn)
- {
- FAR struct tcp_backlog_s *bls;
- FAR struct tcp_blcontainer_s *blc;
- FAR struct tcp_blcontainer_s *prev;
- ninfo("conn=%p blconn=%p\n", conn, blconn);
- #ifdef CONFIG_DEBUG_FEATURES
- if (!conn)
- {
- return -EINVAL;
- }
- #endif
- bls = conn->backlog;
- if (bls)
- {
- /* Find the container hold the connection */
- for (blc = (FAR struct tcp_blcontainer_s *)sq_peek(&bls->bl_pending), prev = NULL;
- blc;
- prev = blc, blc = (FAR struct tcp_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;
- }
- }
- nerr("ERROR: Failed to find pending connection\n");
- return -EINVAL;
- }
- return OK;
- }
- #endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCPBACKLOG */
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