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- /****************************************************************************
- * net/udp/udp_input.c
- * Handling incoming UDP input
- *
- * Copyright (C) 2007-2009, 2011, 2018 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
- *
- * Input Parameters:
- * dev - The device driver structure containing the received UDP packet
- * udp - A pointer to the UDP header in the packet
- * iplen - Length of the IP and UDP headers
- *
- * Returned Value:
- * 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. The
- * device's d_len will be set to zero in this case as there is
- * no outgoing data.
- *
- * Assumptions:
- * The network is locked.
- *
- ****************************************************************************/
- 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
- nwarn("WARNING: 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 and the UDP data was "consumed,"
- * then the UDP_NEWDATA flag will be cleared by logic in
- * udp_callback(). The packet memory can then be freed by the
- * network driver. OK will be returned to the network driver to
- * indicate this case.
- *
- * "Consumed" here means that either the received data was (1)
- * accepted by a socket waiting for data on the port or was (2)
- * buffered in the UDP socket's read-ahead buffer.
- */
- if ((flags & UDP_NEWDATA) != 0)
- {
- /* No.. the packet was not processed now. Return ERROR so
- * that the driver may retry again later. We still need to
- * set d_len to zero so that the driver is aware that there
- * is nothing to be sent.
- */
- nwarn("WARNING: Packet not processed\n");
- dev->d_len = 0;
- ret = ERROR;
- }
- /* If the application has data to send, setup the UDP/IP header */
- if (dev->d_sndlen > 0)
- {
- udp_send(dev, conn);
- }
- }
- else
- {
- nwarn("WARNING: 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
- *
- * Input Parameters:
- * dev - The device driver structure containing the received UDP packet
- *
- * Returned Value:
- * 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
- *
- * Input Parameters:
- * dev - The device driver structure containing the received UDP packet
- * iplen - The size of the IPv6 header. This may be larger than
- * IPv6_HDRLEN the IPv6 header if IPv6 extension headers are
- * present.
- *
- * Returned Value:
- * 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, unsigned int iplen)
- {
- /* Configure to receive an UDP IPv6 packet */
- udp_ipv6_select(dev);
- /* Then process in the UDP IPv6 input */
- return udp_input(dev, iplen);
- }
- #endif
- #endif /* CONFIG_NET && CONFIG_NET_UDP */
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