Simplify RX data path.

Kill off the static single net device and move to proper dynamic
registration (which we need with the new device model).

Break the (flawed) assumption that all network-layer protocols can use
ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP
protocol using ARP_NET_PROTOCOL() and provide a single method for checking
the existence of a local network-layer address.

1 files changed, 154 insertions, 146 deletions

diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index 1825a55b..1197e66c 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -20,6 +20,7 @@
 #include <byteswap.h>
 #include <string.h>
 #include <errno.h>
+#include <malloc.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/pkbuff.h>
 #include <gpxe/tables.h>
@@ -33,175 +34,116 @@
  *
  */
 
-/**
- * Static single instance of a network device
- *
- * The gPXE API is designed to accommodate multiple network devices.
- * However, in the interests of code size, the implementation behind
- * the API supports only a single instance of a network device.
- *
- * No code outside of netdevice.c should ever refer directly to @c
- * static_single_netdev.
- *
- * Callers should always check the return status of alloc_netdev(),
- * register_netdev() etc.  In the current implementation this code
- * will be optimised out by the compiler, so there is no penalty.
- */
-struct net_device static_single_netdev;
-
 /** Registered network-layer protocols */
 static struct net_protocol net_protocols[0] __table_start ( net_protocols );
 static struct net_protocol net_protocols_end[0] __table_end ( net_protocols );
 
-/** Network-layer addresses for @c static_single_netdev */
-static struct net_address static_single_netdev_addresses[0]
-	__table_start ( sgl_netdev_addresses );
-static struct net_address static_single_netdev_addresses_end[0]
-	__table_end ( sgl_netdev_addresses );
-
-/** Recevied packet queue */
-static LIST_HEAD ( rx_queue );
+/** List of network devices */
+static LIST_HEAD ( net_devices );
 
 #warning "Remove this static IP address hack"
 #include <ip.h>
 #include <gpxe/ip.h>
 
 /**
- * Register network device
+ * Transmit raw packet via network device
  *
  * @v netdev		Network device
+ * @v pkb		Packet buffer
  * @ret rc		Return status code
  *
- * Adds the network device to the list of network devices.
+ * Transmits the packet via the specified network device.  This
+ * function takes ownership of the packet buffer.
  */
-int register_netdev ( struct net_device *netdev ) {
-	
-#warning "Remove this static IP address hack"
-	{
-		const struct in_addr static_address = { htonl ( 0x0afefe01 ) };
-		const struct in_addr static_netmask = { htonl ( 0xffffff00 ) };
-		const struct in_addr static_gateway = { INADDR_NONE };
-		int rc;
-		
-		if ( ( rc = add_ipv4_address ( netdev, static_address,
-					       static_netmask,
-					       static_gateway ) ) != 0 )
-			return rc;
-	}
-
-	return 0;
+int netdev_tx ( struct net_device *netdev, struct pk_buff *pkb ) {
+	DBG ( "%s transmitting %p+%zx\n", netdev_name ( netdev ),
+	      pkb->data, pkb_len ( pkb ) );
+	return netdev->transmit ( netdev, pkb );
 }
 
 /**
- * Unregister network device
+ * Add packet to receive queue
  *
  * @v netdev		Network device
+ * @v pkb		Packet buffer
  *
- * Removes the network device from the list of network devices.
+ * The packet is added to the network device's RX queue.  This
+ * function takes ownership of the packet buffer.
  */
-void unregister_netdev ( struct net_device *netdev ) {
-
-#warning "Remove this static IP address hack"
-	del_ipv4_address ( netdev );
-
+void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb ) {
+	DBG ( "%s received %p+%zx\n", netdev_name ( netdev ),
+	      pkb->data, pkb_len ( pkb ) );
+	list_add_tail ( &pkb->list, &netdev->rx_queue );
 }
 
 /**
- * Add packet to receive queue
+ * Transmit network-layer packet
  *
- * @v netdev		Network device
  * @v pkb		Packet buffer
+ * @v netdev		Network device
+ * @v net_protocol	Network-layer protocol
+ * @v ll_dest		Destination link-layer address
+ * @ret rc		Return status code
  *
- * The packet is added to the RX queue.  This function takes ownership
- * of the packet buffer.
+ * Prepends link-layer headers to the packet buffer and transmits the
+ * packet via the specified network device.  This function takes
+ * ownership of the packet buffer.
  */
-void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb ) {
-	DBG ( "Packet received\n" );
-	pkb->ll_protocol = netdev->ll_protocol;
-	list_add_tail ( &pkb->list, &rx_queue );
+int net_tx ( struct pk_buff *pkb, struct net_device *netdev,
+	     struct net_protocol *net_protocol, const void *ll_dest ) {
+	return netdev->ll_protocol->tx ( pkb, netdev, net_protocol, ll_dest );
 }
 
 /**
- * Identify network protocol
+ * Process received network-layer packet
  *
+ * @v pkb		Packet buffer
+ * @v netdev		Network device
  * @v net_proto		Network-layer protocol, in network-byte order
- * @ret net_protocol	Network-layer protocol, or NULL
- *
- * Identify a network-layer protocol from a protocol number, which
- * must be an ETH_P_XXX constant in network-byte order.
+ * @v ll_source		Source link-layer address
  */
-struct net_protocol * find_net_protocol ( uint16_t net_proto ) {
+void net_rx ( struct pk_buff *pkb, struct net_device *netdev,
+	      uint16_t net_proto, const void *ll_source ) {
 	struct net_protocol *net_protocol;
 
+	/* Hand off to network-layer protocol, if any */
 	for ( net_protocol = net_protocols ; net_protocol < net_protocols_end ;
 	      net_protocol++ ) {
-		if ( net_protocol->net_proto == net_proto )
-			return net_protocol;
-	}
-	return NULL;
-}
-
-/**
- * Identify network device by network-layer address
- *
- * @v net_protocol	Network-layer protocol
- * @v net_addr		Network-layer address
- * @ret netdev		Network device, or NULL
- *
- * Searches through all network devices to find the device with the
- * specified network-layer address.
- *
- * Note that even with a static single network device, this function
- * can still return NULL.
- */
-struct net_device *
-find_netdev_by_net_addr ( struct net_protocol *net_protocol,
-			  void *net_addr ) {
-	struct net_address *net_address;
-	struct net_device *netdev = &static_single_netdev;
-	
-	for ( net_address = static_single_netdev_addresses ;
-	      net_address < static_single_netdev_addresses_end ;
-	      net_address ++ ) {
-		if ( ( net_address->net_protocol == net_protocol ) &&
-		     ( memcmp ( net_address->net_addr, net_addr,
-				net_protocol->net_addr_len ) == 0 ) )
-			return netdev;
+		if ( net_protocol->net_proto == net_proto ) {
+			net_protocol->rx ( pkb, netdev, ll_source );
+			break;
+		}
 	}
-
-	return NULL;
 }
 
 /**
- * Poll for packet on all network devices
+ * Poll for packet on network device
  *
+ * @v netdev		Network device
  * @ret True		There are packets present in the receive queue
  * @ret False		There are no packets present in the receive queue
  *
- * Polls all network devices for received packets.  Any received
+ * Polls the network device for received packets.  Any received
  * packets will be added to the RX packet queue via netdev_rx().
  */
-int net_poll ( void ) {
-	struct net_device *netdev = &static_single_netdev;
-
-	DBG ( "Polling network\n" );
+int netdev_poll ( struct net_device *netdev ) {
 	netdev->poll ( netdev );
-
-	return ( ! list_empty ( &rx_queue ) );
+	return ( ! list_empty ( &netdev->rx_queue ) );
 }
 
 /**
- * Remove packet from receive queue
+ * Remove packet from device's receive queue
  *
+ * @v netdev		Network device
  * @ret pkb		Packet buffer, or NULL
  *
- * Removes the first packet from the RX queue and returns it.
+ * Removes the first packet from the device's RX queue and returns it.
  * Ownership of the packet is transferred to the caller.
  */
-struct pk_buff * net_rx_dequeue ( void ) {
+struct pk_buff * netdev_rx_dequeue ( struct net_device *netdev ) {
 	struct pk_buff *pkb;
 
-	list_for_each_entry ( pkb, &rx_queue, list ) {
+	list_for_each_entry ( pkb, &netdev->rx_queue, list ) {
 		list_del ( &pkb->list );
 		return pkb;
 	}
@@ -209,49 +151,109 @@ struct pk_buff * net_rx_dequeue ( void ) {
 }
 
 /**
- * Process received packet
+ * Allocate network device
  *
- * @v pkb		Packet buffer
- * @ret rc		Return status code
+ * @v priv_size		Size of private data area (net_device::priv)
+ * @ret netdev		Network device, or NULL
  *
- * Processes a packet received from the network (and, usually, removed
- * from the RX queue by net_rx_dequeue()).  This call takes ownership
- * of the packet buffer.
+ * Allocates space for a network device and its private data area.
  */
-int net_rx_process ( struct pk_buff *pkb ) {
-	struct ll_protocol *ll_protocol;
-	struct ll_header llhdr;
-	struct net_protocol *net_protocol;
-	int rc;
+struct net_device * alloc_netdev ( size_t priv_size ) {
+	struct net_device *netdev;
 
-	/* Parse link-layer header */
-	ll_protocol = pkb->ll_protocol;
-	ll_protocol->parse_llh ( pkb, &llhdr );
-	
-	/* Identify network-layer protocol */
-	net_protocol = find_net_protocol ( llhdr.net_proto );
-	if ( ! net_protocol ) {
-		DBG ( "Unknown network-layer protocol %x\n",
-		      ntohs ( llhdr.net_proto ) );
-		free_pkb ( pkb );
-		return -EPROTONOSUPPORT;
+	netdev = calloc ( 1, sizeof ( *netdev ) + priv_size );
+	if ( netdev ) {
+		INIT_LIST_HEAD ( &netdev->rx_queue );
+		netdev->priv = ( ( ( void * ) netdev ) + sizeof ( *netdev ) );
 	}
-	pkb->net_protocol = net_protocol;
-	
-	/* Strip off link-layer header */
-#warning "Temporary hack"
-	pkb_pull ( pkb, ETH_HLEN );
+	return netdev;
+}
+
+/**
+ * Register network device
+ *
+ * @v netdev		Network device
+ * @ret rc		Return status code
+ *
+ * Adds the network device to the list of network devices.
+ */
+int register_netdev ( struct net_device *netdev ) {
 	
-	/* Hand off to network layer */
-	if ( ( rc = net_protocol->rx_process ( pkb ) ) != 0 ) {
-		DBG ( "Network-layer protocol dropped packet\n" );
-		return rc;
+#warning "Remove this static IP address hack"
+	{
+		const struct in_addr static_address = { htonl ( 0x0afefe01 ) };
+		const struct in_addr static_netmask = { htonl ( 0xffffff00 ) };
+		const struct in_addr static_gateway = { INADDR_NONE };
+		int rc;
+		
+		if ( ( rc = add_ipv4_address ( netdev, static_address,
+					       static_netmask,
+					       static_gateway ) ) != 0 )
+			return rc;
 	}
 
+	/* Add to device list */
+	list_add_tail ( &netdev->list, &net_devices );
+	DBG ( "%s registered\n", netdev_name ( netdev ) );
+
 	return 0;
 }
 
 /**
+ * Unregister network device
+ *
+ * @v netdev		Network device
+ *
+ * Removes the network device from the list of network devices.
+ */
+void unregister_netdev ( struct net_device *netdev ) {
+	struct pk_buff *pkb;
+
+#warning "Remove this static IP address hack"
+	del_ipv4_address ( netdev );
+
+	/* Discard any packets in the RX queue */
+	while ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
+		DBG ( "%s discarding %p+%zx\n", netdev_name ( netdev ),
+		      pkb->data, pkb_len ( pkb ) );
+		free_pkb ( pkb );
+	}
+
+	/* Remove from device list */
+	list_del ( &netdev->list );
+	DBG ( "%s unregistered\n", netdev_name ( netdev ) );
+}
+
+/**
+ * Free network device
+ *
+ * @v netdev		Network device
+ */
+void free_netdev ( struct net_device *netdev ) {
+	free ( netdev );
+}
+
+/**
+ * Iterate through network devices
+ *
+ * @ret netdev		Network device, or NULL
+ *
+ * This returns the registered network devices in the order of
+ * registration.  If no network devices are registered, it will return
+ * NULL.
+ */
+struct net_device * next_netdev ( void ) {
+	struct net_device *netdev;
+
+	list_for_each_entry ( netdev, &net_devices, list ) {
+		list_del ( &netdev->list );
+		list_add_tail ( &netdev->list, &net_devices );
+		return netdev;
+	}
+	return NULL;
+}
+
+/**
  * Single-step the network stack
  *
  * @v process		Network stack process
@@ -266,15 +268,21 @@ int net_rx_process ( struct pk_buff *pkb ) {
  * multiple packets are processed per poll.
  */
 static void net_step ( struct process *process ) {
+	struct net_device *netdev;
 	struct pk_buff *pkb;
 
-	/* Poll for new packets */
-	net_poll();
+	/* Poll and process each network device */
+	list_for_each_entry ( netdev, &net_devices, list ) {
+
+		/* Poll for new packets */
+		netdev_poll ( netdev );
 
-	/* Handle at most one received packet */
-	if ( ( pkb = net_rx_dequeue () ) ) {
-		net_rx_process ( pkb );
-		DBG ( "Processed received packet\n" );
+		/* Handle at most one received packet per poll */
+		if ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
+			DBG ( "%s processing %p+%zx\n", netdev_name ( netdev ),
+			      pkb->data, pkb_len ( pkb ) );
+			netdev->ll_protocol->rx ( pkb, netdev );
+		}
 	}
 
 	/* Re-schedule ourself */