fb8cf9373c
In connection-mode UDP sockets, a remote address is retained in the UDP connection structure. This determines both there send() will send the packets and which packets recv() will accept. This same mechanism is used for connection-less UDP sendto: A temporary remote address is written into the connection structure to support the sendto() operation. That address persists until the next recvfrom() when it is reset to accept any address. When UDP read-ahead buffering is enabled, however, that means that the old, invalid remote address can be left in the connection structure for some time. This can cause read-ahead buffer to fail, dropping UDP packets. Shortening the time between when he remote address is reset (i.e., immediately after the sendto() completes) is not a solution, that does not eliminate the race condition; in only makes it smaller. With this change, a flag was added to the connection structure to indicate if the UDP socket is in connection mode or if it is connection-less. This change effects only UDP receive operations: The remote address in the UDP connection is always ignored if the UDP socket is not in connection-mode. No for connection-mode sockets, that remote address behaves as before. But for connection-less sockets, it is only used by sendto().
217 lines
6.8 KiB
C
217 lines
6.8 KiB
C
/****************************************************************************
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* net/udp/udp_finddev.c
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*
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* Copyright (C) 2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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/config.h>
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#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)
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#include <string.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/ip.h>
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#include "netdev/netdev.h"
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#include "inet/inet.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_find_ipv4_device
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*
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* Description:
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* Select the network driver to use with the IPv4 UDP transaction.
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*
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* Input Parameters:
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* conn - UDP connection structure (not currently used).
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* ipv4addr - The IPv4 address to use in the device selection.
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*
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* Returned Value:
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* A pointer to the network driver to use.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_IPv4
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FAR struct net_driver_s *udp_find_ipv4_device(FAR struct udp_conn_s *conn,
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in_addr_t ipv4addr)
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{
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/* Return NULL if the address is INADDR_ANY. In this case, there may
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* be multiple devices that can provide data so the exceptional events
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* from any particular device are not important.
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*
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* Of course, it would be a problem if this is the remote address of
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* sendto().
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*/
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if (net_ipv4addr_cmp(ipv4addr, INADDR_ANY))
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{
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return NULL;
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}
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/* We need to select the device that is going to route the UDP packet
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* based on the provided IP address.
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*/
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return netdev_findby_ipv4addr(conn->u.ipv4.laddr, ipv4addr);
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}
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#endif /* CONFIG_NET_IPv4 */
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/****************************************************************************
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* Name: udp_find_ipv6_device
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*
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* Description:
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* Select the network driver to use with the IPv6 UDP transaction.
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*
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* Input Parameters:
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* conn - UDP connection structure (not currently used).
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* ipv6addr - The IPv6 address to use in the device selection.
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*
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* Returned Value:
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* A pointer to the network driver to use.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_IPv6
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FAR struct net_driver_s *udp_find_ipv6_device(FAR struct udp_conn_s *conn,
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net_ipv6addr_t ipv6addr)
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{
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/* Return NULL if the address is IN6ADDR_ANY. In this case, there may
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* be multiple devices that can provide data so the exceptional events
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* from any particular device are not important.
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*
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* Of course, it would be a problem if this is the remote address of
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* sendto().
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*/
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if (net_ipv6addr_cmp(ipv6addr, g_ipv6_allzeroaddr))
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{
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return NULL;
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}
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/* We need to select the device that is going to route the UDP packet
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* based on the provided IP address.
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*/
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return netdev_findby_ipv6addr(conn->u.ipv6.laddr, ipv6addr);
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}
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#endif /* CONFIG_NET_IPv6 */
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/****************************************************************************
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* Name: udp_find_laddr_device
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*
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* Description:
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* Select the network driver to use with the UDP transaction using the
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* locally bound IP address.
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*
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* Input Parameters:
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* conn - UDP connection structure (not currently used).
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*
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* Returned Value:
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* A pointer to the network driver to use.
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*
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****************************************************************************/
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FAR struct net_driver_s *udp_find_laddr_device(FAR struct udp_conn_s *conn)
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{
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/* There are multiple network devices. We need to select the device that
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* is going to route the UDP packet based on the provided IP address.
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*/
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#ifdef CONFIG_NET_IPv4
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#ifdef CONFIG_NET_IPv6
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if (conn->domain == PF_INET)
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#endif
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{
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return udp_find_ipv4_device(conn, conn->u.ipv4.laddr);
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}
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#endif
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#ifdef CONFIG_NET_IPv6
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#ifdef CONFIG_NET_IPv4
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else
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#endif
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{
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return udp_find_ipv6_device(conn, conn->u.ipv6.laddr);
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}
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#endif
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}
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/****************************************************************************
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* Name: udp_find_raddr_device
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*
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* Description:
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* Select the network driver to use with the UDP transaction using the
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* remote IP address.
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*
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* Input Parameters:
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* conn - UDP connection structure.
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*
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* Returned Value:
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* A pointer to the network driver to use.
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*
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****************************************************************************/
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FAR struct net_driver_s *udp_find_raddr_device(FAR struct udp_conn_s *conn)
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{
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/* We need to select the device that is going to route the UDP packet
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* based on the provided IP address.
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*/
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#ifdef CONFIG_NET_IPv4
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#ifdef CONFIG_NET_IPv6
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if (conn->domain == PF_INET)
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#endif
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{
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return udp_find_ipv4_device(conn, conn->u.ipv4.raddr);
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}
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#endif
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#ifdef CONFIG_NET_IPv6
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#ifdef CONFIG_NET_IPv4
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else
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#endif
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{
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return udp_find_ipv6_device(conn, conn->u.ipv6.raddr);
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}
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#endif
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}
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#endif /* CONFIG_NET && CONFIG_NET_UDP */
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