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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git
The following commit(s) were added to refs/heads/master by this push:
new 1e25602 net/can,icmp,icmpv6,tcp,tcp_timer,udp: device should poll
only those connections that are bound to the device. tcp_timer: eliminated
false decrements of conn->timer in case of multiple network adapters. The false
timer decrements sometimes provoked TCP spurious retransmissions due to
premature timeouts.
1e25602 is described below
commit 1e2560267898f413c93c5fb616ddc5b1d4d07184
Author: Alexander Lunev <alexanderlu...@mail.ru>
AuthorDate: Sat Oct 2 03:47:08 2021 +0300
net/can,icmp,icmpv6,tcp,tcp_timer,udp: device should poll only those
connections that are bound to the device.
tcp_timer: eliminated false decrements of conn->timer in case of multiple
network adapters.
The false timer decrements sometimes provoked TCP spurious retransmissions
due to premature timeouts.
---
net/can/can_poll.c | 29 ++---
net/devif/devif_poll.c | 101 +++++++++++-------
net/icmp/icmp_poll.c | 5 +
net/icmpv6/icmpv6_poll.c | 6 ++
net/tcp/tcp_devpoll.c | 50 ++++-----
net/tcp/tcp_timer.c | 267 ++++++++++++++++++++++-------------------------
net/udp/udp_devpoll.c | 11 ++
7 files changed, 247 insertions(+), 222 deletions(-)
diff --git a/net/can/can_poll.c b/net/can/can_poll.c
index c968fe2..3caed22 100644
--- a/net/can/can_poll.c
+++ b/net/can/can_poll.c
@@ -26,6 +26,7 @@
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_CAN)
+#include <assert.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
@@ -53,31 +54,31 @@
*
* Assumptions:
* The network is locked.
+ * dev is not NULL.
+ * conn is not NULL.
+ * The connection (conn) is bound to the polling device (dev).
*
****************************************************************************/
void can_poll(FAR struct net_driver_s *dev, FAR struct can_conn_s *conn)
{
- /* Verify that the packet connection is valid */
+ DEBUGASSERT(dev != NULL && conn != NULL && dev == conn->dev);
- if (conn != NULL)
- {
- /* Setup for the application callback */
+ /* Setup for the application callback */
- dev->d_appdata = &dev->d_buf[NET_LL_HDRLEN(dev)];
- dev->d_len = 0;
- dev->d_sndlen = 0;
+ dev->d_appdata = &dev->d_buf[NET_LL_HDRLEN(dev)];
+ dev->d_len = 0;
+ dev->d_sndlen = 0;
- /* Perform the application callback */
+ /* Perform the application callback */
- can_callback(dev, conn, CAN_POLL);
+ can_callback(dev, conn, CAN_POLL);
- /* Check if the application has data to send */
+ /* Check if the application has data to send */
- if (dev->d_sndlen > 0)
- {
- return;
- }
+ if (dev->d_sndlen > 0)
+ {
+ return;
}
/* Make sure that d_len is zero meaning that there is nothing to be sent */
diff --git a/net/devif/devif_poll.c b/net/devif/devif_poll.c
index 6865742..4b14c73 100644
--- a/net/devif/devif_poll.c
+++ b/net/devif/devif_poll.c
@@ -248,10 +248,12 @@ static int devif_poll_can_connections(FAR struct
net_driver_s *dev,
while (!bstop && (can_conn = can_nextconn(can_conn)))
{
- /* Perform the packet TX poll */
+ /* Skip connections that are bound to other polling devices */
if (dev == can_conn->dev)
{
+ /* Perform the packet TX poll */
+
can_poll(dev, can_conn);
/* Call back into the driver */
@@ -361,17 +363,22 @@ static inline int devif_poll_icmp(FAR struct net_driver_s
*dev,
while (!bstop && (conn = icmp_nextconn(conn)) != NULL)
{
- /* Perform the ICMP poll */
+ /* Skip ICMP connections that are bound to other polling devices */
- icmp_poll(dev, conn);
+ if (dev == conn->dev)
+ {
+ /* Perform the ICMP poll */
- /* Perform any necessary conversions on outgoing packets */
+ icmp_poll(dev, conn);
- devif_packet_conversion(dev, DEVIF_ICMP);
+ /* Perform any necessary conversions on outgoing packets */
- /* Call back into the driver */
+ devif_packet_conversion(dev, DEVIF_ICMP);
- bstop = callback(dev);
+ /* Call back into the driver */
+
+ bstop = callback(dev);
+ }
}
return bstop;
@@ -393,27 +400,32 @@ static inline int devif_poll_icmpv6(FAR struct
net_driver_s *dev,
FAR struct icmpv6_conn_s *conn = NULL;
int bstop = 0;
- /* Traverse all of the allocated ICMPV6 connections and perform the poll
+ /* Traverse all of the allocated ICMPv6 connections and perform the poll
* action.
*/
do
{
- /* Perform the ICMPV6 poll
- * Note: conn equal NULL in the first iteration means poll dev's
- * callback list since icmpv6_autoconfig and icmpv6_neighbor still
- * append it's callback into this list.
- */
+ /* Skip ICMPv6 connections that are bound to other polling devices */
- icmpv6_poll(dev, conn);
+ if (conn == NULL || dev == conn->dev)
+ {
+ /* Perform the ICMPV6 poll
+ * Note: conn equal NULL in the first iteration means poll dev's
+ * callback list since icmpv6_autoconfig and icmpv6_neighbor still
+ * append it's callback into this list.
+ */
- /* Perform any necessary conversions on outgoing packets */
+ icmpv6_poll(dev, conn);
- devif_packet_conversion(dev, DEVIF_ICMP6);
+ /* Perform any necessary conversions on outgoing packets */
- /* Call back into the driver */
+ devif_packet_conversion(dev, DEVIF_ICMP6);
- bstop = callback(dev);
+ /* Call back into the driver */
+
+ bstop = callback(dev);
+ }
}
while (!bstop && (conn = icmpv6_nextconn(conn)) != NULL);
@@ -533,17 +545,24 @@ static int devif_poll_udp_connections(FAR struct
net_driver_s *dev,
while (!bstop && (conn = udp_nextconn(conn)))
{
- /* Perform the UDP TX poll */
+#ifdef CONFIG_NET_UDP_WRITE_BUFFERS
+ /* Skip UDP connections that are bound to other polling devices */
- udp_poll(dev, conn);
+ if (dev == conn->dev)
+#endif
+ {
+ /* Perform the UDP TX poll */
- /* Perform any necessary conversions on outgoing packets */
+ udp_poll(dev, conn);
- devif_packet_conversion(dev, DEVIF_UDP);
+ /* Perform any necessary conversions on outgoing packets */
- /* Call back into the driver */
+ devif_packet_conversion(dev, DEVIF_UDP);
- bstop = callback(dev);
+ /* Call back into the driver */
+
+ bstop = callback(dev);
+ }
}
return bstop;
@@ -573,17 +592,22 @@ static inline int devif_poll_tcp_connections(FAR struct
net_driver_s *dev,
while (!bstop && (conn = tcp_nextconn(conn)))
{
- /* Perform the TCP TX poll */
+ /* Skip TCP connections that are bound to other polling devices */
- tcp_poll(dev, conn);
+ if (dev == conn->dev)
+ {
+ /* Perform the TCP TX poll */
- /* Perform any necessary conversions on outgoing packets */
+ tcp_poll(dev, conn);
- devif_packet_conversion(dev, DEVIF_TCP);
+ /* Perform any necessary conversions on outgoing packets */
- /* Call back into the driver */
+ devif_packet_conversion(dev, DEVIF_TCP);
- bstop = callback(dev);
+ /* Call back into the driver */
+
+ bstop = callback(dev);
+ }
}
return bstop;
@@ -619,17 +643,22 @@ static inline int devif_poll_tcp_timer(FAR struct
net_driver_s *dev,
while (!bstop && (conn = tcp_nextconn(conn)))
{
- /* Perform the TCP timer poll */
+ /* Skip TCP connections that are bound to other polling devices */
- tcp_timer(dev, conn, hsec);
+ if (dev == conn->dev)
+ {
+ /* Perform the TCP timer poll */
- /* Perform any necessary conversions on outgoing packets */
+ tcp_timer(dev, conn, hsec);
- devif_packet_conversion(dev, DEVIF_TCP);
+ /* Perform any necessary conversions on outgoing packets */
- /* Call back into the driver */
+ devif_packet_conversion(dev, DEVIF_TCP);
- bstop = callback(dev);
+ /* Call back into the driver */
+
+ bstop = callback(dev);
+ }
}
return bstop;
diff --git a/net/icmp/icmp_poll.c b/net/icmp/icmp_poll.c
index f0f76c6..bd0f761 100644
--- a/net/icmp/icmp_poll.c
+++ b/net/icmp/icmp_poll.c
@@ -54,11 +54,16 @@
*
* Assumptions:
* The network is locked.
+ * dev is not NULL.
+ * conn is not NULL.
+ * The connection (conn) is bound to the polling device (dev).
*
****************************************************************************/
void icmp_poll(FAR struct net_driver_s *dev, FAR struct icmp_conn_s *conn)
{
+ DEBUGASSERT(dev != NULL && conn != NULL && dev == conn->dev);
+
/* Setup for the application callback */
dev->d_appdata = &dev->d_buf[NET_LL_HDRLEN(dev) + IPICMP_HDRLEN];
diff --git a/net/icmpv6/icmpv6_poll.c b/net/icmpv6/icmpv6_poll.c
index 63d89f6..5124739 100644
--- a/net/icmpv6/icmpv6_poll.c
+++ b/net/icmpv6/icmpv6_poll.c
@@ -53,12 +53,18 @@
*
* Assumptions:
* The network is locked.
+ * dev is not NULL.
+ * conn may be NULL.
+ * The connection (conn), if not NULL, is bound to
+ * the polling device (dev).
*
****************************************************************************/
void icmpv6_poll(FAR struct net_driver_s *dev,
FAR struct icmpv6_conn_s *conn)
{
+ DEBUGASSERT(dev != NULL && (conn == NULL || dev == conn->dev));
+
/* Setup for the application callback */
dev->d_appdata = &dev->d_buf[NET_LL_HDRLEN(dev) + IPICMPv6_HDRLEN];
diff --git a/net/tcp/tcp_devpoll.c b/net/tcp/tcp_devpoll.c
index e1b7da2..30fd278 100644
--- a/net/tcp/tcp_devpoll.c
+++ b/net/tcp/tcp_devpoll.c
@@ -74,7 +74,10 @@
* None
*
* Assumptions:
- * Called with the network locked.
+ * It is called with the network locked.
+ * dev is not NULL.
+ * conn is not NULL.
+ * The connection (conn) is bound to the polling device (dev).
*
****************************************************************************/
@@ -82,6 +85,8 @@ void tcp_poll(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn)
{
uint16_t result;
+ DEBUGASSERT(dev != NULL && conn != NULL && dev == conn->dev);
+
/* Discard any currently buffered data */
dev->d_len = 0;
@@ -91,43 +96,34 @@ void tcp_poll(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn)
if ((conn->tcpstateflags & TCP_STATE_MASK) == TCP_ESTABLISHED)
{
- /* The TCP connection is established and, hence, should be bound
- * to a device. Make sure that the polling device is the one that
- * we are bound to.
+ /* Set up for the callback. We can't know in advance if the
+ * application is going to send a IPv4 or an IPv6 packet, so this
+ * setup may not actually be used.
*/
- DEBUGASSERT(conn->dev != NULL);
- if (dev == conn->dev)
- {
- /* Set up for the callback. We can't know in advance if the
- * application is going to send a IPv4 or an IPv6 packet, so this
- * setup may not actually be used.
- */
-
#if defined(CONFIG_NET_IPv6) && defined(CONFIG_NET_IPv4)
- if (conn->domain == PF_INET)
- {
- tcp_ipv4_select(dev);
- }
- else
- {
- tcp_ipv6_select(dev);
- }
+ if (conn->domain == PF_INET)
+ {
+ tcp_ipv4_select(dev);
+ }
+ else
+ {
+ tcp_ipv6_select(dev);
+ }
#elif defined(CONFIG_NET_IPv4)
- tcp_ipv4_select(dev);
+ tcp_ipv4_select(dev);
#else /* if defined(CONFIG_NET_IPv6) */
- tcp_ipv6_select(dev);
+ tcp_ipv6_select(dev);
#endif
- /* Perform the callback */
+ /* Perform the callback */
- result = tcp_callback(dev, conn, TCP_POLL);
+ result = tcp_callback(dev, conn, TCP_POLL);
- /* Handle the callback response */
+ /* Handle the callback response */
- tcp_appsend(dev, conn, result);
- }
+ tcp_appsend(dev, conn, result);
}
}
diff --git a/net/tcp/tcp_timer.c b/net/tcp/tcp_timer.c
index 4e8fc13..7ecb987 100644
--- a/net/tcp/tcp_timer.c
+++ b/net/tcp/tcp_timer.c
@@ -94,6 +94,9 @@
*
* Assumptions:
* The network is locked.
+ * dev is not NULL.
+ * conn is not NULL.
+ * The connection (conn) is bound to the polling device (dev).
*
****************************************************************************/
@@ -103,6 +106,14 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn,
uint16_t result;
uint8_t hdrlen;
+ /* NOTE: It is important to decrease conn->timer at "hsec" pace,
+ * not faster. Excessive (false) decrements of conn->timer are not allowed
+ * here. Otherwise, it breaks TCP timings and leads to TCP spurious
+ * retransmissions and other issues due to premature timeouts.
+ */
+
+ DEBUGASSERT(dev != NULL && conn != NULL && dev == conn->dev);
+
/* Set up for the callback. We can't know in advance if the application
* is going to send a IPv4 or an IPv6 packet, so this setup may not
* actually be used. Furthermore, the TCP logic is required to call
@@ -140,6 +151,13 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn,
dev->d_len = 0;
dev->d_sndlen = 0;
+ if (conn->tcpstateflags == TCP_CLOSED)
+ {
+ /* Nothing to be done */
+
+ return;
+ }
+
/* Check if the connection is in a state in which we simply wait
* for the connection to time out. If so, we increase the
* connection's timer and remove the connection if it times
@@ -162,30 +180,13 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn,
/* Set the timer to the maximum value */
conn->timer = TCP_TIME_WAIT_TIMEOUT * HSEC_PER_SEC;
+ conn->tcpstateflags = TCP_CLOSED;
- /* The TCP connection was established and, hence, should be bound
- * to a device. Make sure that the polling device is the one that
- * we are bound to.
- *
- * If not, then we will catch the timeout on the next poll from
- * the correct device.
- */
-
- DEBUGASSERT(conn->dev != NULL);
- if (dev != conn->dev)
- {
- ninfo("TCP: TCP_CLOSED pending\n");
- }
- else
- {
- conn->tcpstateflags = TCP_CLOSED;
-
- /* Notify upper layers about the timeout */
+ /* Notify upper layers about the timeout */
- tcp_callback(dev, conn, TCP_TIMEDOUT);
+ tcp_callback(dev, conn, TCP_TIMEDOUT);
- ninfo("TCP state: TCP_CLOSED\n");
- }
+ ninfo("TCP state: TCP_CLOSED\n");
}
else
{
@@ -217,21 +218,6 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn,
conn->timer = 0;
- /* The TCP is connected and, hence, should be bound to a
- * device. Make sure that the polling device is the one that
- * we are bound to.
- *
- * If not, then we will catch the timeout on the next poll
- * from the correct device.
- */
-
- DEBUGASSERT(conn->dev != NULL);
- if (dev != conn->dev)
- {
- ninfo("TCP: TCP_CLOSED pending\n");
- goto done;
- }
-
/* Check for a timeout on connection in the TCP_SYN_RCVD state.
* On such timeouts, we would normally resend the SYNACK until
* the ACK is received, completing the 3-way handshake. But if
@@ -370,157 +356,148 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct
tcp_conn_s *conn,
else if ((conn->tcpstateflags & TCP_STATE_MASK) == TCP_ESTABLISHED)
{
- /* The TCP connection is established and, hence, should be bound
- * to a device. Make sure that the polling device is the one that
- * we are bound to.
- */
+#ifdef CONFIG_NET_TCP_KEEPALIVE
+ /* Is this an established connected with KeepAlive enabled? */
- DEBUGASSERT(conn->dev != NULL);
- if (dev == conn->dev)
+ if (conn->keepalive)
{
-#ifdef CONFIG_NET_TCP_KEEPALIVE
- /* Is this an established connected with KeepAlive enabled? */
+ socktimeo_t timeo;
+ uint32_t saveseq;
- if (conn->keepalive)
+ /* If this is the first probe, then the keepstart time is
+ * the time that the last ACK or data was received from the
+ * remote.
+ *
+ * On subsequent retries, keepstart is the time that the
+ * last probe was sent.
+ */
+
+ if (conn->keepretries > 0)
{
- socktimeo_t timeo;
- uint32_t saveseq;
-
- /* If this is the first probe, then the keepstart time is
- * the time that the last ACK or data was received from the
- * remote.
- *
- * On subsequent retries, keepstart is the time that the
- * last probe was sent.
- */
+ timeo = (socktimeo_t)conn->keepintvl;
+ }
+ else
+ {
+ timeo = (socktimeo_t)conn->keepidle;
+ }
- if (conn->keepretries > 0)
- {
- timeo = (socktimeo_t)conn->keepintvl;
- }
- else
- {
- timeo = (socktimeo_t)conn->keepidle;
- }
+ /* Yes... has the idle period elapsed with no data or ACK
+ * received from the remote peer?
+ */
- /* Yes... has the idle period elapsed with no data or ACK
- * received from the remote peer?
- */
+ if (net_timeo(conn->keeptime, timeo))
+ {
+ /* Yes.. Has the retry count expired? */
- if (net_timeo(conn->keeptime, timeo))
+ if (conn->keepretries >= conn->keepcnt)
{
- /* Yes.. Has the retry count expired? */
-
- if (conn->keepretries >= conn->keepcnt)
- {
- /* Yes... stop the network monitor, closing the
- * connection and all sockets associated with the
- * connection.
- */
+ /* Yes... stop the network monitor, closing the
+ * connection and all sockets associated with the
+ * connection.
+ */
- tcp_stop_monitor(conn, TCP_ABORT);
- }
- else
- {
- unsigned int tcpiplen;
+ tcp_stop_monitor(conn, TCP_ABORT);
+ }
+ else
+ {
+ unsigned int tcpiplen;
- /* No.. we need to send another probe.
- * Get the size of the IP and TCP header.
- */
+ /* No.. we need to send another probe.
+ * Get the size of the IP and TCP header.
+ */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
- if (conn->domain == PF_INET)
+ if (conn->domain == PF_INET)
#endif
- {
- tcpiplen = IPv4_HDRLEN + TCP_HDRLEN;
- }
+ {
+ tcpiplen = IPv4_HDRLEN + TCP_HDRLEN;
+ }
#endif
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
- else
+ else
#endif
- {
- tcpiplen = IPv6_HDRLEN + TCP_HDRLEN;
- }
+ {
+ tcpiplen = IPv6_HDRLEN + TCP_HDRLEN;
+ }
#endif
- /* And send the probe.
- * The packet we send must have these properties:
- *
- * - TCP_ACK flag (only) is set.
- * - Sequence number is the sequence number of
- * previously ACKed data, i.e., the expected
- * sequence number minus one.
- *
- * tcp_send() will send the TCP sequence number as
- * conn->sndseq. Rather than creating a new
- * interface, we spoof tcp_end() here:
- */
+ /* And send the probe.
+ * The packet we send must have these properties:
+ *
+ * - TCP_ACK flag (only) is set.
+ * - Sequence number is the sequence number of
+ * previously ACKed data, i.e., the expected
+ * sequence number minus one.
+ *
+ * tcp_send() will send the TCP sequence number as
+ * conn->sndseq. Rather than creating a new
+ * interface, we spoof tcp_end() here:
+ */
- saveseq = tcp_getsequence(conn->sndseq);
- tcp_setsequence(conn->sndseq, saveseq - 1);
+ saveseq = tcp_getsequence(conn->sndseq);
+ tcp_setsequence(conn->sndseq, saveseq - 1);
- tcp_send(dev, conn, TCP_ACK, tcpiplen);
+ tcp_send(dev, conn, TCP_ACK, tcpiplen);
- tcp_setsequence(conn->sndseq, saveseq);
+ tcp_setsequence(conn->sndseq, saveseq);
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
- /* Increment the un-ACKed sequence number */
+ /* Increment the un-ACKed sequence number */
- conn->sndseq_max++;
+ conn->sndseq_max++;
#endif
- /* Update for the next probe */
-
- conn->keeptime = clock_systime_ticks();
- conn->keepretries++;
- }
+ /* Update for the next probe */
- goto done;
+ conn->keeptime = clock_systime_ticks();
+ conn->keepretries++;
}
+
+ goto done;
}
+ }
#endif
#ifdef CONFIG_NET_TCP_DELAYED_ACK
- /* Handle delayed acknowledgments. Is there a segment with a
- * delayed acknowledgment?
- */
+ /* Handle delayed acknowledgments. Is there a segment with a
+ * delayed acknowledgment?
+ */
- if (conn->rx_unackseg > 0)
- {
- /* Increment the ACK delay. */
+ if (conn->rx_unackseg > 0)
+ {
+ /* Increment the ACK delay. */
- conn->rx_acktimer += hsec;
+ conn->rx_acktimer += hsec;
- /* Per RFC 1122: "...an ACK should not be excessively
- * delayed; in particular, the delay must be less than
- * 0.5 seconds..."
- */
+ /* Per RFC 1122: "...an ACK should not be excessively
+ * delayed; in particular, the delay must be less than
+ * 0.5 seconds..."
+ */
- if (conn->rx_acktimer >= ACK_DELAY)
- {
- /* Reset the delayed ACK state and send the ACK
- * packet.
- */
+ if (conn->rx_acktimer >= ACK_DELAY)
+ {
+ /* Reset the delayed ACK state and send the ACK
+ * packet.
+ */
- conn->rx_unackseg = 0;
- conn->rx_acktimer = 0;
- tcp_synack(dev, conn, TCP_ACK);
- goto done;
- }
+ conn->rx_unackseg = 0;
+ conn->rx_acktimer = 0;
+ tcp_synack(dev, conn, TCP_ACK);
+ goto done;
}
+ }
#endif
- /* There was no need for a retransmission and there was no
- * need to probe the remote peer and there was no need to
- * send a delayed ACK. We poll the application for new
- * outgoing data.
- */
+ /* There was no need for a retransmission and there was no
+ * need to probe the remote peer and there was no need to
+ * send a delayed ACK. We poll the application for new
+ * outgoing data.
+ */
- result = tcp_callback(dev, conn, TCP_POLL);
- tcp_appsend(dev, conn, result);
- goto done;
- }
+ result = tcp_callback(dev, conn, TCP_POLL);
+ tcp_appsend(dev, conn, result);
+ goto done;
}
}
diff --git a/net/udp/udp_devpoll.c b/net/udp/udp_devpoll.c
index 92eaf04..7796f8f 100644
--- a/net/udp/udp_devpoll.c
+++ b/net/udp/udp_devpoll.c
@@ -45,6 +45,7 @@
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)
+#include <assert.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
@@ -73,11 +74,21 @@
*
* Assumptions:
* The network is locked.
+ * dev is not NULL.
+ * conn is not NULL.
+ * The connection (conn) is bound to the polling device (dev) in case of
+ * enabled CONFIG_NET_UDP_WRITE_BUFFERS option.
*
****************************************************************************/
void udp_poll(FAR struct net_driver_s *dev, FAR struct udp_conn_s *conn)
{
+ DEBUGASSERT(dev != NULL && conn != NULL);
+
+#ifdef CONFIG_NET_UDP_WRITE_BUFFERS
+ DEBUGASSERT(dev == conn->dev);
+#endif
+
/* Verify that the UDP connection is valid */
if (conn->lport != 0)
