295 lines
8.7 KiB
C
295 lines
8.7 KiB
C
/****************************************************************************
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* net/tcp/tcp_wrbuffer.c
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*
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* Copyright (C) 2007-2009, 2013-2014, 2018 Gregory Nutt. All rights
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* reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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* Jason Jiang <jasonj@live.cn>
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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_DEBUG_FEATURES) && defined(CONFIG_NET_TCP_WRBUFFER_DEBUG)
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/* Force debug output (from this file only) */
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# undef CONFIG_DEBUG_NET
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# define CONFIG_DEBUG_NET 1
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#endif
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#include <queue.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/net/net.h>
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#include <nuttx/mm/iob.h>
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#include "utils/utils.h"
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#include "tcp/tcp.h"
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#if defined(CONFIG_NET_TCP) && defined(CONFIG_NET_TCP_WRITE_BUFFERS)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* Package all globals used by this logic into a structure */
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struct wrbuffer_s
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{
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/* The semaphore to protect the buffers */
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sem_t sem;
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/* This is the list of available write buffers */
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sq_queue_t freebuffers;
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/* These are the pre-allocated write buffers */
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struct tcp_wrbuffer_s buffers[CONFIG_NET_TCP_NWRBCHAINS];
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};
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* This is the state of the global write buffer resource */
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static struct wrbuffer_s g_wrbuffer;
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tcp_wrbuffer_initialize
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*
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* Description:
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* Initialize the list of free write buffers
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*
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* Assumptions:
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* Called once early initialization.
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*
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****************************************************************************/
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void tcp_wrbuffer_initialize(void)
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{
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int i;
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sq_init(&g_wrbuffer.freebuffers);
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for (i = 0; i < CONFIG_NET_TCP_NWRBCHAINS; i++)
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{
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sq_addfirst(&g_wrbuffer.buffers[i].wb_node, &g_wrbuffer.freebuffers);
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}
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nxsem_init(&g_wrbuffer.sem, 0, CONFIG_NET_TCP_NWRBCHAINS);
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nxsem_setprotocol(&g_wrbuffer.sem, SEM_PRIO_NONE);
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}
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/****************************************************************************
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* Name: tcp_wrbuffer_alloc
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*
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* Description:
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* Allocate a TCP write buffer by taking a pre-allocated buffer from
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* the free list. This function is called from TCP logic when a buffer
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* of TCP data is about to sent
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*
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* Input Parameters:
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* None
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*
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* Assumptions:
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* Called from user logic with the network locked.
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*
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****************************************************************************/
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FAR struct tcp_wrbuffer_s *tcp_wrbuffer_alloc(void)
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{
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FAR struct tcp_wrbuffer_s *wrb;
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/* We need to allocate two things: (1) A write buffer structure and (2)
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* at least one I/O buffer to start the chain.
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*
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* Allocate the write buffer structure first then the IOB. In order to
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* avoid deadlocks, we will need to free the IOB first, then the write
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* buffer
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*/
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net_lockedwait_uninterruptible(&g_wrbuffer.sem);
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/* Now, we are guaranteed to have a write buffer structure reserved
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* for us in the free list.
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*/
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wrb = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&g_wrbuffer.freebuffers);
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DEBUGASSERT(wrb);
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memset(wrb, 0, sizeof(struct tcp_wrbuffer_s));
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/* Now get the first I/O buffer for the write buffer structure */
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wrb->wb_iob = net_ioballoc(false, IOBUSER_NET_TCP_WRITEBUFFER);
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/* Did we get an IOB? We should always get one except under some really
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* weird error conditions.
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*/
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if (wrb->wb_iob == NULL)
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{
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nerr("ERROR: Failed to allocate I/O buffer\n");
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tcp_wrbuffer_release(wrb);
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return NULL;
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}
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return wrb;
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}
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/****************************************************************************
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* Name: tcp_wrbuffer_tryalloc
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*
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* Description:
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* Try to allocate a TCP write buffer by taking a pre-allocated buffer from
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* the free list. This function is called from TCP logic when a buffer
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* of TCP data is about to be sent on a non-blocking socket. Returns
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* immediately if the allocation failed.
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*
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* Input parameters:
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* None
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*
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* Assumptions:
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* Called from user logic with the network locked. Will return if no buffer
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* is available.
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*
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****************************************************************************/
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FAR struct tcp_wrbuffer_s *tcp_wrbuffer_tryalloc(void)
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{
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FAR struct tcp_wrbuffer_s *wrb;
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/* We need to allocate two things: (1) A write buffer structure and (2)
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* at least one I/O buffer to start the chain.
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*
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* Allocate the write buffer structure first then the IOBG. In order to
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* avoid deadlocks, we will need to free the IOB first, then the write
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* buffer
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*/
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if (nxsem_trywait(&g_wrbuffer.sem) != OK)
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{
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return NULL;
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}
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/* Now, we are guaranteed to have a write buffer structure reserved
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* for us in the free list.
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*/
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wrb = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&g_wrbuffer.freebuffers);
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DEBUGASSERT(wrb);
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memset(wrb, 0, sizeof(struct tcp_wrbuffer_s));
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/* Now get the first I/O buffer for the write buffer structure */
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wrb->wb_iob = iob_tryalloc(false, IOBUSER_NET_TCP_WRITEBUFFER);
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if (!wrb->wb_iob)
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{
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nerr("ERROR: Failed to allocate I/O buffer\n");
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tcp_wrbuffer_release(wrb);
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return NULL;
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}
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return wrb;
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}
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/****************************************************************************
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* Name: tcp_wrbuffer_release
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*
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* Description:
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* Release a TCP write buffer by returning the buffer to the free list.
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* This function is called from user logic after it is consumed the
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* buffered data.
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*
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* Assumptions:
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* This function must be called with the network locked.
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*
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****************************************************************************/
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void tcp_wrbuffer_release(FAR struct tcp_wrbuffer_s *wrb)
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{
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DEBUGASSERT(wrb != NULL);
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/* To avoid deadlocks, we must following this ordering: Release the I/O
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* buffer chain first, then the write buffer structure.
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*/
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if (wrb->wb_iob != NULL)
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{
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iob_free_chain(wrb->wb_iob, IOBUSER_NET_TCP_WRITEBUFFER);
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}
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/* Then free the write buffer structure */
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sq_addlast(&wrb->wb_node, &g_wrbuffer.freebuffers);
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nxsem_post(&g_wrbuffer.sem);
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}
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/****************************************************************************
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* Name: tcp_wrbuffer_test
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*
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* Description:
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* Check if there is room in the write buffer. Does not reserve any space.
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*
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* Assumptions:
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* None.
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*
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****************************************************************************/
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int tcp_wrbuffer_test(void)
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{
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int val = 0;
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int ret;
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ret = nxsem_getvalue(&g_wrbuffer.sem, &val);
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if (ret >= 0)
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{
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ret = val > 0 ? OK : -ENOSPC;
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}
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return ret;
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}
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#endif /* CONFIG_NET_TCP && CONFIG_NET_TCP_WRITE_BUFFERS */
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