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nuttx/net/udp/udp_input.c

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/****************************************************************************
* net/udp/udp_input.c
* Handling incoming UDP input
*
* Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Adapted for NuttX from logic in uIP which also has a BSD-like license:
*
* Original author Adam Dunkels <adam@dunkels.com>
* Copyright () 2001-2003, Adam Dunkels.
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)
#include <debug.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/udp.h>
#include <nuttx/net/netstats.h>
#include "devif/devif.h"
#include "utils/utils.h"
#include "udp/udp.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: udp_input
*
* Description:
* Handle incoming UDP input
*
* Parameters:
* dev - The device driver structure containing the received UDP packet
* udp - A pointer to the UDP header in the packet
* udpiplen - Length of the IP and UDP headers
*
* Return:
* OK The packet has been processed and can be deleted
* ERROR Hold the packet and try again later. There is a listening socket
* but no receive in place to catch the packet yet.
*
* Assumptions:
* Called from the interrupt level or with interrupts disabled.
*
****************************************************************************/
static int udp_input(FAR struct net_driver_s *dev, unsigned int iplen)
{
FAR struct udp_hdr_s *udp;
FAR struct udp_conn_s *conn;
unsigned int udpiplen;
unsigned int hdrlen;
#ifdef CONFIG_NET_UDP_CHECKSUMS
uint16_t chksum;
#endif
int ret = OK;
/* Update the count of UDP packets received */
#ifdef CONFIG_NET_STATISTICS
g_netstats.udp.recv++;
#endif
/* Get a pointer to the UDP header. The UDP header lies just after the
* the link layer header and the IP header.
*/
udp = (FAR struct udp_hdr_s *)&dev->d_buf[iplen + NET_LL_HDRLEN(dev)];
/* Get the size of the IP header and the UDP header */
udpiplen = iplen + UDP_HDRLEN;
/* Get the size of the link layer header, the IP header, and the UDP header */
hdrlen = udpiplen + NET_LL_HDRLEN(dev);
/* UDP processing is really just a hack. We don't do anything to the UDP/IP
* headers, but let the UDP application do all the hard work. If the
* application sets d_sndlen, it has a packet to send.
*/
dev->d_len -= udpiplen;
dev->d_appdata = &dev->d_buf[hdrlen];
#ifdef CONFIG_NET_UDP_CHECKSUMS
chksum = udp->udpchksum;
if (chksum != 0)
{
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
if (IFF_IS_IPv6(dev->d_flags))
#endif
{
chksum = ~udp_ipv6_chksum(dev);
}
#endif /* CONFIG_NET_IPv6 */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
else
#endif
{
chksum = ~udp_ipv4_chksum(dev);
}
#endif /* CONFIG_NET_IPv6 */
}
if (chksum != 0)
{
#ifdef CONFIG_NET_STATISTICS
g_netstats.udp.drop++;
g_netstats.udp.chkerr++;
#endif
nlldbg("Bad UDP checksum\n");
dev->d_len = 0;
}
else
#endif
{
/* Demultiplex this UDP packet between the UDP "connections".
*
* REVISIT: The logic here expects either a single receive socket or
* none at all. However, multiple sockets should be capable of
* receiving a UDP datagram (multicast reception). This could be
* handled easily by something like:
*
* for (conn = NULL; conn = udp_active(dev, udp); )
*
* If the callback logic that receives a packet responds with an
* outgoing packet, then it will over-write the received buffer,
* however. recvfrom() will not do that, however. We would have to
* make that the rule: Recipients of a UDP packet must treat the
* packet as read-only.
*/
conn = udp_active(dev, udp);
if (conn)
{
uint16_t flags;
/* Set-up for the application callback */
dev->d_appdata = &dev->d_buf[hdrlen];
dev->d_sndlen = 0;
/* Perform the application callback */
flags = udp_callback(dev, conn, UDP_NEWDATA);
/* If the operation was successful, the UDP_NEWDATA flag is removed
* and thus the packet can be deleted (OK will be returned).
*/
if ((flags & UDP_NEWDATA) != 0)
{
/* No.. the packet was not processed now. Return ERROR so
* that the driver may retry again later.
*/
ret = ERROR;
}
/* If the application has data to send, setup the UDP/IP header */
if (dev->d_sndlen > 0)
{
udp_send(dev, conn);
}
}
else
{
nlldbg("No listener on UDP port\n");
dev->d_len = 0;
}
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: udp_ipv4_input
*
* Description:
* Handle incoming UDP input in an IPv4 packet
*
* Parameters:
* dev - The device driver structure containing the received UDP packet
*
* Return:
* OK The packet has been processed and can be deleted
* ERROR Hold the packet and try again later. There is a listening socket
* but no receive in place to catch the packet yet.
*
* Assumptions:
* Called from network stack logic with the network stack locked
*
****************************************************************************/
#ifdef CONFIG_NET_IPv4
int udp_ipv4_input(FAR struct net_driver_s *dev)
{
/* Configure to receive an UDP IPv4 packet */
udp_ipv4_select(dev);
/* Then process in the UDP IPv4 input */
return udp_input(dev, IPv4_HDRLEN);
}
#endif
/****************************************************************************
* Name: udp_ipv6_input
*
* Description:
* Handle incoming UDP input in an IPv6 packet
*
* Parameters:
* dev - The device driver structure containing the received UDP packet
*
* Return:
* OK The packet has been processed and can be deleted
* ERROR Hold the packet and try again later. There is a listening socket
* but no receive in place to catch the packet yet.
*
* Assumptions:
* Called from network stack logic with the network stack locked
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int udp_ipv6_input(FAR struct net_driver_s *dev)
{
/* Configure to receive an UDP IPv6 packet */
udp_ipv6_select(dev);
/* Then process in the UDP IPv6 input */
return udp_input(dev, IPv6_HDRLEN);
}
#endif
#endif /* CONFIG_NET && CONFIG_NET_UDP */
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