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, 41 insertions, 15 deletions

diff --git a/src/net/arp.c b/src/net/arp.c
index 66f9bd4c..6293bf95 100644
--- a/src/net/arp.c
+++ b/src/net/arp.c
@@ -36,6 +36,12 @@
  *
  */
 
+/** Registered ARP protocols */
+static struct arp_net_protocol arp_net_protocols[0]
+	__table_start ( arp_net_protocols );
+static struct arp_net_protocol arp_net_protocols_end[0]
+	__table_end ( arp_net_protocols );
+
 /** An ARP cache entry */
 struct arp_entry {
 	/** Network-layer protocol */
@@ -134,7 +140,6 @@ int arp_resolve ( struct net_device *netdev, struct net_protocol *net_protocol,
 			  2 * ( MAX_LL_ADDR_LEN + MAX_NET_ADDR_LEN ) );
 	if ( ! pkb )
 		return -ENOMEM;
-	pkb->net_protocol = &arp_protocol;
 	pkb_reserve ( pkb, MAX_LL_HEADER_LEN );
 
 	/* Build up ARP request */
@@ -154,17 +159,38 @@ int arp_resolve ( struct net_device *netdev, struct net_protocol *net_protocol,
 		 dest_net_addr, net_protocol->net_addr_len );
 
 	/* Transmit ARP request */
-	if ( ( rc = net_transmit ( pkb, netdev, &arp_protocol, 
-				   ll_protocol->ll_broadcast ) ) != 0 )
+	if ( ( rc = net_tx ( pkb, netdev, &arp_protocol, 
+			     ll_protocol->ll_broadcast ) ) != 0 )
 		return rc;
 
 	return -ENOENT;
 }
 
 /**
+ * Identify ARP protocol
+ *
+ * @v net_proto			Network-layer protocol, in network-endian order
+ * @ret arp_net_protocol	ARP protocol, or NULL
+ *
+ */
+static struct arp_net_protocol * arp_find_protocol ( uint16_t net_proto ) {
+	struct arp_net_protocol *arp_net_protocol;
+
+	for ( arp_net_protocol = arp_net_protocols ;
+	      arp_net_protocol < arp_net_protocols_end ; arp_net_protocol++ ) {
+		if ( arp_net_protocol->net_protocol->net_proto == net_proto ) {
+			return arp_net_protocol;
+		}
+	}
+	return NULL;
+}
+
+/**
  * Process incoming ARP packets
  *
  * @v pkb		Packet buffer
+ * @v netdev		Network device
+ * @v ll_source		Link-layer source address
  * @ret rc		Return status code
  *
  * This handles ARP requests and responses as detailed in RFC826.  The
@@ -173,19 +199,21 @@ int arp_resolve ( struct net_device *netdev, struct net_protocol *net_protocol,
  * avoiding the need for extraneous ARP requests; read the RFC for
  * details.
  */
-static int arp_rx ( struct pk_buff *pkb ) {
+static int arp_rx ( struct pk_buff *pkb, struct net_device *netdev,
+		    const void *ll_source __unused ) {
 	struct arphdr *arphdr = pkb->data;
-	struct ll_protocol *ll_protocol;
+	struct arp_net_protocol *arp_net_protocol;
 	struct net_protocol *net_protocol;
+	struct ll_protocol *ll_protocol;
 	struct arp_entry *arp;
-	struct net_device *netdev;
 	int merge = 0;
 
-	/* Identify link-layer and network-layer protocols */
-	ll_protocol = pkb->ll_protocol;
-	net_protocol = find_net_protocol ( arphdr->ar_pro );
-	if ( ! net_protocol )
+	/* Identify network-layer and link-layer protocols */
+	arp_net_protocol = arp_find_protocol ( arphdr->ar_pro );
+	if ( ! arp_net_protocol )
 		goto done;
+	net_protocol = arp_net_protocol->net_protocol;
+	ll_protocol = netdev->ll_protocol;
 
 	/* Sanity checks */
 	if ( ( arphdr->ar_hrd != ll_protocol->ll_proto ) ||
@@ -206,9 +234,7 @@ static int arp_rx ( struct pk_buff *pkb ) {
 	}
 
 	/* See if we own the target protocol address */
-	netdev = find_netdev_by_net_addr ( net_protocol,
-					   arp_target_pa ( arphdr ) );
-	if ( ! netdev )
+	if ( arp_net_protocol->check ( netdev, arp_target_pa ( arphdr ) ) != 0)
 		goto done;
 	
 	/* Create new ARP table entry if necessary */
@@ -239,7 +265,7 @@ static int arp_rx ( struct pk_buff *pkb ) {
 	memcpy ( arp_sender_ha ( arphdr ), netdev->ll_addr, arphdr->ar_hln );
 
 	/* Send reply */
-	net_transmit ( pkb, netdev, &arp_protocol, arp_target_ha (arphdr ) );
+	net_tx ( pkb, netdev, &arp_protocol, arp_target_ha (arphdr ) );
 	pkb = NULL;
 
  done:
@@ -264,7 +290,7 @@ arp_ntoa ( const void *net_addr __attribute__ (( unused )) ) {
 struct net_protocol arp_protocol = {
 	.name = "ARP",
 	.net_proto = htons ( ETH_P_ARP ),
-	.rx_process = arp_rx,
+	.rx = arp_rx,
 	.ntoa = arp_ntoa,
 };