/**************************************************************************** * net/udp/udp_input.c * Handling incoming UDP input * * Copyright (C) 2007-2009, 2011, 2018-2019 Gregory Nutt. All rights * reserved. * Author: Gregory Nutt * * Adapted for NuttX from logic in uIP which also has a BSD-like license: * * Original author Adam Dunkels * 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 #if defined(CONFIG_NET) && defined(CONFIG_NET_UDP) #include #include #include #include #include #include "devif/devif.h" #include "utils/utils.h" #include "udp/udp.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define IPv4BUF ((FAR struct ipv4_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) /**************************************************************************** * 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 * -EAGAIN - 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 -EAGAIN 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 = -EAGAIN; } /* 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) { FAR struct ipv4_hdr_s *ipv4 = IPv4BUF; uint16_t iphdrlen; /* Configure to receive an UDP IPv4 packet */ udp_ipv4_select(dev); /* Get the IP header length (accounting for possible options). */ iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2; /* Then process in the UDP IPv4 input */ return udp_input(dev, iphdrlen); } #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 */