Allow recording of TX and RX errors to aid in end-user debugging.

src/include/gpxe/netdevice.h

  */
 struct net_device_stats {
 	/** Count of successfully completed transmissions */
-	unsigned int tx_count;
+	unsigned int tx_ok;
+	/** Count of transmission errors */
+	unsigned int tx_err;
 	/** Count of successfully received packets */
-	unsigned int rx_count;
+	unsigned int rx_ok;
+	/** Count of reception errors */
+	unsigned int rx_err;
 };
 
 /**
 	 * owned by the net device's TX queue, and the net device must
 	 * eventually call netdev_tx_complete() to free the buffer.
 	 * If this method returns failure, the I/O buffer is
-	 * immediately released.
+	 * immediately released; the failure is interpreted as
+	 * "failure to enqueue buffer".
 	 *
 	 * This method is guaranteed to be called only when the device
 	 * is open.
 }
 
 extern int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf );
-extern void netdev_tx_complete ( struct net_device *netdev,
-				 struct io_buffer *iobuf );
-extern void netdev_tx_complete_next ( struct net_device *netdev );
+extern void netdev_tx_complete_err ( struct net_device *netdev,
+				 struct io_buffer *iobuf, int rc );
+extern void netdev_tx_complete_next_err ( struct net_device *netdev, int rc );
 extern void netdev_rx ( struct net_device *netdev, struct io_buffer *iobuf );
+extern void netdev_rx_err ( struct net_device *netdev,
+			    struct io_buffer *iobuf, int rc );
 extern int netdev_poll ( struct net_device *netdev, unsigned int rx_quota );
 extern struct io_buffer * netdev_rx_dequeue ( struct net_device *netdev );
 extern struct net_device * alloc_netdev ( size_t priv_size );
 extern int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    uint16_t net_proto, const void *ll_source );
 
+/**
+ * Complete network transmission
+ *
+ * @v netdev		Network device
+ * @v iobuf		I/O buffer
+ *
+ * The packet must currently be in the network device's TX queue.
+ */
+static inline void netdev_tx_complete ( struct net_device *netdev,
+					struct io_buffer *iobuf ) {
+	netdev_tx_complete_err ( netdev, iobuf, 0 );
+}
+
+/**
+ * Complete network transmission
+ *
+ * @v netdev		Network device
+ *
+ * Completes the oldest outstanding packet in the TX queue.
+ */
+static inline void netdev_tx_complete_next ( struct net_device *netdev ) {
+	netdev_tx_complete_next_err ( netdev, 0 );
+}
+
 #endif /* _GPXE_NETDEVICE_H */

src/interface/pxe/pxe_undi.c

 					 *undi_get_statistics ) {
 	DBG ( "PXENV_UNDI_GET_STATISTICS" );
 
-	undi_get_statistics->XmtGoodFrames = pxe_netdev->stats.tx_count;
-	undi_get_statistics->RcvGoodFrames = pxe_netdev->stats.rx_count;
-	undi_get_statistics->RcvCRCErrors = 0;
-	undi_get_statistics->RcvResourceErrors = 0;
+	undi_get_statistics->XmtGoodFrames = pxe_netdev->stats.tx_ok;
+	undi_get_statistics->RcvGoodFrames = pxe_netdev->stats.rx_ok;
+	undi_get_statistics->RcvCRCErrors = pxe_netdev->stats.rx_err;
+	undi_get_statistics->RcvResourceErrors = pxe_netdev->stats.rx_err;
 
 	undi_get_statistics->Status = PXENV_STATUS_SUCCESS;
 	return PXENV_EXIT_SUCCESS;

src/net/netdevice.c

 	return 0;
 
  err:
-	DBGC ( netdev, "NETDEV %p transmission %p failed: %s\n",
-	       netdev, iobuf, strerror ( rc ) );
-	netdev_tx_complete ( netdev, iobuf );
+	netdev_tx_complete_err ( netdev, iobuf, rc );
 	return rc;
 }
 
  *
  * @v netdev		Network device
  * @v iobuf		I/O buffer
+ * @v rc		Packet status code
  *
  * The packet must currently be in the network device's TX queue.
  */
-void netdev_tx_complete ( struct net_device *netdev, struct io_buffer *iobuf ) {
-	DBGC ( netdev, "NETDEV %p transmission %p complete\n", netdev, iobuf );
+void netdev_tx_complete_err ( struct net_device *netdev,
+			      struct io_buffer *iobuf, int rc ) {
+
+	/* Update statistics counter */
+	if ( rc == 0 ) {
+		netdev->stats.tx_ok++;
+		DBGC ( netdev, "NETDEV %p transmission %p complete\n",
+		       netdev, iobuf );
+	} else {
+		netdev->stats.tx_err++;
+		DBGC ( netdev, "NETDEV %p transmission %p failed: %s\n",
+		       netdev, iobuf, strerror ( rc ) );
+	}
 
 	/* Catch data corruption as early as possible */
 	assert ( iobuf->list.next != NULL );
 	/* Dequeue and free I/O buffer */
 	list_del ( &iobuf->list );
 	free_iob ( iobuf );
-
-	/* Update statistics counter */
-	netdev->stats.tx_count++;
 }
 
 /**
  * Complete network transmission
  *
  * @v netdev		Network device
+ * @v rc		Packet status code
  *
  * Completes the oldest outstanding packet in the TX queue.
  */
-void netdev_tx_complete_next ( struct net_device *netdev ) {
+void netdev_tx_complete_next_err ( struct net_device *netdev, int rc ) {
 	struct io_buffer *iobuf;
 
 	list_for_each_entry ( iobuf, &netdev->tx_queue, list ) {
-		netdev_tx_complete ( netdev, iobuf );
+		netdev_tx_complete_err ( netdev, iobuf, rc );
 		return;
 	}
 }
 
 	/* Discard any packets in the TX queue */
 	while ( ! list_empty ( &netdev->tx_queue ) ) {
-		netdev_tx_complete_next ( netdev );
+		netdev_tx_complete_next_err ( netdev, -ECANCELED );
 	}
 }
 
  * Add packet to receive queue
  *
  * @v netdev		Network device
- * @v iobuf		I/O buffer
+ * @v iobuf		I/O buffer, or NULL
  *
  * The packet is added to the network device's RX queue.  This
  * function takes ownership of the I/O buffer.
  */
 void netdev_rx ( struct net_device *netdev, struct io_buffer *iobuf ) {
+
 	DBGC ( netdev, "NETDEV %p received %p (%p+%zx)\n",
 	       netdev, iobuf, iobuf->data, iob_len ( iobuf ) );
 
 	list_add_tail ( &iobuf->list, &netdev->rx_queue );
 
 	/* Update statistics counter */
-	netdev->stats.rx_count++;
+	netdev->stats.rx_ok++;
+}
+
+/**
+ * Discard received packet
+ *
+ * @v netdev		Network device
+ * @v iobuf		I/O buffer, or NULL
+ * @v rc		Packet status code
+ *
+ * The packet is discarded and an RX error is recorded.  This function
+ * takes ownership of the I/O buffer.  @c iobuf may be NULL if, for
+ * example, the net device wishes to report an error due to being
+ * unable to allocate an I/O buffer.
+ */
+void netdev_rx_err ( struct net_device *netdev,
+		     struct io_buffer *iobuf, int rc ) {
+
+	DBGC ( netdev, "NETDEV %p failed to receive %p: %s\n",
+	       netdev, iobuf, strerror ( rc ) );
+
+	/* Discard packet */
+	free_iob ( iobuf );
+
+	/* Update statistics counter */
+	netdev->stats.rx_err++;
 }
 
 /**
 
 	/* Discard any packets in the RX queue */
 	while ( ( iobuf = netdev_rx_dequeue ( netdev ) ) ) {
-		DBGC ( netdev, "NETDEV %p discarding received %p\n",
-		       netdev, iobuf );
-		free_iob ( iobuf );
+		netdev_rx_err ( netdev, iobuf, -ECANCELED );
 	}
 }
 

src/usr/ifmgmt.c

  * @v netdev		Network device
  */
 void ifstat ( struct net_device *netdev ) {
-	printf ( "%s: %s on %s (%s) TX:%d RX:%d\n",
+	printf ( "%s: %s on %s (%s) TX:%d TXE:%d RX:%d RXE:%d\n",
 		 netdev->name, netdev_hwaddr ( netdev ), netdev->dev->name,
 		 ( ( netdev->state & NETDEV_OPEN ) ? "open" : "closed" ),
-		 netdev->stats.tx_count, netdev->stats.rx_count );
+		 netdev->stats.tx_ok, netdev->stats.tx_err,
+		 netdev->stats.rx_ok, netdev->stats.rx_err );
 }