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nuttx/net/udp/udp_forward.c

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/****************************************************************************
* net/udp/udp_forward.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <net/if.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/netstats.h>
#include "devif/ip_forward.h"
#include "devif/devif.h"
#include "netdev/netdev.h"
#include "arp/arp.h"
#include "neighbor/neighbor.h"
#include "udp/udp.h"
#if defined(CONFIG_NET_IPFORWARD) && defined(CONFIG_NET_UDP) && \
defined(CONFIG_NETDEV_MULTINIC)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: forward_ipselect
*
* Description:
* If both IPv4 and IPv6 support are enabled, then we will need to select
* which one to use when generating the outgoing packet. If only one
* domain is selected, then the setup is already in place and we need do
* nothing.
*
* Parameters:
* fwd - The forwarding state structure
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
static inline void forward_ipselect(FAR struct forward_s *fwd)
{
FAR union fwd_iphdr_u *iphdr = FWD_HEADER(fwd);
/* Select IPv4 or IPv6 */
if ((iphdr->ipv4.l2.vhl & IP_VERSION_MASK) == IPv4_VERSION)
{
udp_ipv4_select(fwd->f_dev);
}
else
{
udp_ipv6_select(fwd->f_dev);
}
}
#endif
/****************************************************************************
* Name: udp_forward_addrchk
*
* Description:
* Check if the destination IP address is in the IPv4 ARP or IPv6 Neighbor
* tables. If not, then the send won't actually make it out... it will be
* replaced with an ARP request (IPv4) or a Neighbor Solicitation (IPv6).
*
* NOTE 1: This could be an expensive check if there are a lot of
* entries in the ARP or Neighbor tables.
*
* NOTE 2: If we are actually harvesting IP addresses on incoming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table in many cases (IPv4 only).
*
* NOTE 3: If CONFIG_NET_ARP_SEND then we can be assured that the IP
* address mapping is already in the ARP table.
*
* Parameters:
* fwd - The forwarding state structure
*
* Returned Value:
* true - The Ethernet MAC address is in the ARP or Neighbor table (OR
* the network device is not Ethernet).
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#ifdef CONFIG_NET_ETHERNET
static inline bool udp_forward_addrchk(FAR struct forward_s *fwd)
{
FAR union fwd_iphdr_u *iphdr;
DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL);
/* REVISIT: Could the MAC address not also be in a routing table? */
#ifdef CONFIG_NET_MULTILINK
if (fwd->f_dev->d_lltype != NET_LL_ETHERNET)
{
return true;
}
#endif
iphdr = FWD_HEADER(fwd);
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if ((iphdr->ipv4.l2.vhl & IP_VERSION_MASK) == IPv4_VERSION)
#endif
{
#if !defined(CONFIG_NET_ARP_IPIN) && !defined(CONFIG_NET_ARP_SEND)
return (arp_find(iphdr->ipv4.l2.destipaddr) != NULL);
#else
return true;
#endif
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
#if !defined(CONFIG_NET_ICMPv6_NEIGHBOR)
return (neighbor_findentry(iphdr->ipv6.l2.destipaddr) != NULL);
#else
return true;
#endif
}
#endif /* CONFIG_NET_IPv6 */
}
#else /* CONFIG_NET_ETHERNET */
# define udp_forward_addrchk(r) (true)
#endif /* CONFIG_NET_ETHERNET */
/****************************************************************************
* Name: udp_dropstats
*
* Description:
* Update statistics for a dropped packet.
*
* Input Parameters:
* fwd - The forwarding state structure
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_NET_STATISTICS
static void udp_dropstats(FAR struct forward_s *fwd)
{
#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
FAR union fwd_iphdr_u *iphdr = FWD_HEADER(fwd);
#endif
/* Increment the count of dropped UDP packets */
g_netstats.udp.drop++;
/* Increment the count of dropped IPv4 or IPv6 packets */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if ((iphdr->ipv4.l2.vhl & IP_VERSION_MASK) == IPv4_VERSION)
#endif
{
g_netstats.ipv4.drop++;
}
#endif
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
g_netstats.ipv6.drop++;
}
#endif
}
#else
# define udp_dropstats(ipv6)
#endif
/****************************************************************************
* Name: udp_forward_interrupt
*
* Description:
* This function is called from the interrupt level to perform the actual
* send operation when polled by the lower, device interfacing layer.
*
* Parameters:
* dev The structure of the network driver that caused the interrupt
* conn An instance of the UDP connection structure cast to void *
* pvpriv An instance of struct forward_s cast to void*
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* Modified value of the input flags
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static uint16_t udp_forward_interrupt(FAR struct net_driver_s *dev,
FAR void *conn, FAR void *pvpriv,
uint16_t flags)
{
FAR struct forward_s *fwd = (FAR struct forward_s *)pvpriv;
ninfo("flags: %04x\n", flags);
DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL);
/* Make sure that this is from the forwarding device */
if (dev == fwd->f_dev)
{
/* If the network device has gone down, then we will have terminate
* the wait now with an error.
*/
if ((flags & NETDEV_DOWN) != 0)
{
/* Terminate the transfer with an error. */
nwarn("WARNING: Network is down... Dropping\n");
udp_dropstats(fwd);
}
/* Check if the outgoing packet is available. It may have been claimed
* by a sendto interrupt serving a different thread -OR- if the output
* buffer currently contains unprocessed incoming data. In these cases
* we will just have to wait for the next polling cycle.
*/
else if (dev->d_sndlen > 0 || (flags & UDP_NEWDATA) != 0)
{
/* Another thread has beat us sending data or the buffer is busy,
* Wait for the next polling cycle and check again.
*/
return flags;
}
/* It looks like we are good to forward the data */
else
{
#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
/* If both IPv4 and IPv6 support are enabled, then we will need to
* select which one to use when generating the outgoing packet.
* If only one domain is selected, then the setup is already in
* place and we need do nothing.
*/
forward_ipselect(fwd);
#endif
/* Copy the user data into d_appdata and send it. */
devif_forward(fwd);
/* Check if the destination IP address is in the ARP or Neighbor
* table. If not, then the send won't actually make it out... it
* will be replaced with an ARP request or Neighbor Solicitation.
*/
if (!udp_forward_addrchk(fwd))
{
return flags;
}
}
/* Free the allocated callback structure */
fwd->f_cb->flags = 0;
fwd->f_cb->priv = NULL;
fwd->f_cb->event = NULL;
udp_callback_free(dev, &fwd->f_conn.udp, fwd->f_cb);
/* Free any IOBs */
if (fwd->f_iob != NULL)
{
iob_free_chain(fwd->f_iob);
}
/* And release the forwarding state structure */
ip_forward_free(fwd);
}
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: udp_forward
*
* Description:
* Called by the IP forwarding logic when an UDP packet is received on
* one network device, but must be forwarded on another network device.
*
* Set up to forward the UDP packet on the specified device. This
* function will set up a send "interrupt" handler that will perform the
* actual send asynchronously and must return without waiting for the
* send to complete.
*
* Input Parameters:
* fwd - An initialized instance of the common forwarding structure that
* includes everything needed to perform the forwarding operation.
*
* Returned Value:
* Zero is returned if the packet was successfully forwarded; A negated
* errno value is returned if the packet is not forwardable. In that
* latter case, the caller should free the IOB list and drop the packet.
*
****************************************************************************/
int udp_forward(FAR struct forward_s *fwd)
{
DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL);
/* Set up the callback in the connection */
fwd->f_cb = udp_callback_alloc(fwd->f_dev, &fwd->f_conn.udp);
if (fwd->f_cb != NULL)
{
fwd->f_cb->flags = (UDP_POLL | NETDEV_DOWN);
fwd->f_cb->priv = (FAR void *)fwd;
fwd->f_cb->event = udp_forward_interrupt;
/* Notify the device driver of the availability of TX data */
netdev_txnotify_dev(fwd->f_dev);
return OK;
}
return -EBUSY;
}
#endif /* CONFIG_NET_IPFORWARD && CONFIG_NET_UDP && CONFIG_NETDEV_MULTINIC */
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