[netdevice] Allow per-device receive queue processing to be frozen

Several use cases (e.g. the UNDI API and the EFI SNP API) require
access to the raw network device receive queue, and so currently use
manual calls to netdev_poll() on a specific network device in order to
prevent received packets from being processed by the network stack.

As an alternative, provide a flag that allows receive queue processing
to be frozen on a per-device basis.  When receive queue processing is
frozen, packets will be enqueued as normal, but will not be
automatically dequeued and passed up the network stack.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 37 insertions, 2 deletions

diff --git a/src/include/ipxe/netdevice.h b/src/include/ipxe/netdevice.h
index 4649377..26e2ab8 100644
--- a/src/include/ipxe/netdevice.h
+++ b/src/include/ipxe/netdevice.h
@@ -343,6 +343,9 @@ struct net_device {
 /** Network device interrupts are enabled */
 #define NETDEV_IRQ_ENABLED 0x0002
 
+/** Network device receive queue processing is frozen */
+#define NETDEV_RX_FROZEN 0x0004
+
 /** Link-layer protocol table */
 #define LL_PROTOCOLS __table ( struct ll_protocol, "ll_protocols" )
 
@@ -505,7 +508,7 @@ netdev_link_ok ( struct net_device *netdev ) {
  * Check whether or not network device is open
  *
  * @v netdev		Network device
- * @v is_open		Network device is open
+ * @ret is_open		Network device is open
  */
 static inline __attribute__ (( always_inline )) int
 netdev_is_open ( struct net_device *netdev ) {
@@ -516,13 +519,24 @@ netdev_is_open ( struct net_device *netdev ) {
  * Check whether or not network device interrupts are currently enabled
  *
  * @v netdev		Network device
- * @v irq_enabled	Network device interrupts are enabled
+ * @ret irq_enabled	Network device interrupts are enabled
  */
 static inline __attribute__ (( always_inline )) int
 netdev_irq_enabled ( struct net_device *netdev ) {
 	return ( netdev->state & NETDEV_IRQ_ENABLED );
 }
 
+/**
+ * Check whether or not network device receive queue processing is frozen
+ *
+ * @v netdev		Network device
+ * @ret rx_frozen	Network device receive queue processing is frozen
+ */
+static inline __attribute__ (( always_inline )) int
+netdev_rx_frozen ( struct net_device *netdev ) {
+	return ( netdev->state & NETDEV_RX_FROZEN );
+}
+
 extern void netdev_link_err ( struct net_device *netdev, int rc );
 extern void netdev_link_down ( struct net_device *netdev );
 extern int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf );
@@ -550,6 +564,7 @@ extern int net_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 extern int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    uint16_t net_proto, const void *ll_dest,
 		    const void *ll_source );
+extern void net_poll ( void );
 
 /**
  * Complete network transmission
@@ -585,4 +600,24 @@ netdev_link_up ( struct net_device *netdev ) {
 	netdev_link_err ( netdev, 0 );
 }
 
+/**
+ * Freeze network device receive queue processing
+ *
+ * @v netdev		Network device
+ */
+static inline __attribute__ (( always_inline )) void
+netdev_rx_freeze ( struct net_device *netdev ) {
+	netdev->state |= NETDEV_RX_FROZEN;
+}
+
+/**
+ * Unfreeze network device receive queue processing
+ *
+ * @v netdev		Network device
+ */
+static inline __attribute__ (( always_inline )) void
+netdev_rx_unfreeze ( struct net_device *netdev ) {
+	netdev->state &= ~NETDEV_RX_FROZEN;
+}
+
 #endif /* _IPXE_NETDEVICE_H */