8a63d29c6e
Allocate the device buffer only if the protocol really need to send data. not all protocols require the driver to prepare additional iob before sending, especially UDP, each iob reserves l2/l3 header in advance after prepare write buffer, net device could reuse this entry to send directly Signed-off-by: chao an <anchao@xiaomi.com>
118 lines
3.9 KiB
C
118 lines
3.9 KiB
C
/****************************************************************************
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* net/udp/udp_devpoll.c
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* Network device poll for the availability of UDP TX data
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*
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* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Adapted for NuttX from logic in uIP which also has a BSD-like license:
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*
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* Original author Adam Dunkels <adam@dunkels.com>
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* Copyright () 2001-2003, Adam Dunkels.
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* All rights reserved.
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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 the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE 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/config.h>
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#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/net/netconfig.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/udp.h>
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#include "devif/devif.h"
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#include "udp/udp.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: udp_poll
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*
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* Description:
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* Poll a UDP "connection" structure for availability of TX data
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*
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* Input Parameters:
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* dev - The device driver structure to use in the send operation
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* conn - The UDP "connection" to poll for TX data
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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* The network is locked.
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* dev is not NULL.
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* conn is not NULL.
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* The connection (conn) is bound to the polling device (dev) in case of
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* enabled CONFIG_NET_UDP_WRITE_BUFFERS option.
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*
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****************************************************************************/
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void udp_poll(FAR struct net_driver_s *dev, FAR struct udp_conn_s *conn)
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{
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DEBUGASSERT(dev != NULL && conn != NULL);
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#ifdef CONFIG_NET_UDP_WRITE_BUFFERS
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DEBUGASSERT(dev == conn->dev);
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#endif
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/* Verify that the UDP connection is valid */
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if (conn->lport != 0)
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{
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dev->d_len = 0;
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dev->d_sndlen = 0;
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/* Perform the application callback */
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udp_callback(dev, conn, UDP_POLL);
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/* If the application has data to send, setup the UDP/IP header */
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if (dev->d_sndlen > 0)
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{
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udp_send(dev, conn);
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return;
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}
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}
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/* Make sure that d_len is zero meaning that there is nothing to be sent */
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dev->d_len = 0;
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}
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#endif /* CONFIG_NET && CONFIG_NET_UDP */
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