Renamed net/interface.c and include/gpxe/interface.h to net/tcpip_if.c and include/gpxe/tcpip_if.h respectively. Made changes in the other files.

src/include/gpxe/ip.h

@@ -32,6 +32,7 @@ struct ipv4_pseudo_header {
 struct pk_buff;
 struct net_device;
 struct net_protocol;
+struct tcpip_protocol;
 
 extern struct net_protocol ipv4_protocol;
 
@@ -41,6 +42,7 @@ extern int add_ipv4_address ( struct net_device *netdev,
 extern void del_ipv4_address ( struct net_device *netdev );
 
 extern int ipv4_uip_tx ( struct pk_buff *pkb );
-extern int ipv4_tx ( struct pk_buff *pkb, uint16_t trans_proto, struct in_addr *dest );
+extern int ipv4_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip,
+		     struct in_addr *dest );
 
 #endif /* _GPXE_IP_H */

src/include/gpxe/tcpip_if.h

@@ -0,0 +1,91 @@
+#ifndef _GPXE_INTERFACE_H
+#define _GPXE_INTERFACE_H
+
+/** @file
+ *
+ * Transport-network layer interface
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/in.h>
+#include <gpxe/tables.h>
+
+struct pk_buff;
+struct net_protocol;
+struct tcpip_protocol;
+struct tcpip_net_protocol;
+
+/** 
+ * A transport-layer protocol of the TCPIP stack (eg. UDP, TCP, etc)
+ */
+struct tcpip_protocol {
+	/** Protocol name */
+	const char *name;
+       	/**
+         * Process received packet
+         *
+         * @v pkb       Packet buffer
+         * @v netdev    Network device
+         * @v ll_source Link-layer source address
+         *
+         * This method takes ownership of the packet buffer.
+         */
+        void ( * rx ) ( struct pk_buff *pkb, struct in_addr *src_net_addr, struct in_addr *dest_net_addr );
+        /** 
+	 * Transport-layer protocol number
+	 *
+	 * This is a constant of the type IP_XXX
+         */
+        uint8_t trans_proto;
+	/**
+	 * Checksum offset
+	 *
+	 * A negative number indicates that the protocol does not require
+	 * checksumming to be performed by the network layer. A positive number is
+	 * the offset of the checksum field in the transport-layer header.
+	 */
+	int csum_offset;
+};
+
+/**
+ * A TCPIP supporting network-layer protocol
+ */
+struct tcpip_net_protocol {
+	/** Network protocol */
+	struct net_protocol *net_protocol;
+	/** Network address family */
+	sa_family_t sa_family;
+	/** Complete transport-layer checksum calculation
+	 *
+	 * @v pkb		Packet buffer
+	 * @v tcpip		Transport-layer protocol
+	 *
+	 */
+	void ( * tx_csum ) ( struct pk_buff *pkb,
+			     struct tcpip_protocol *tcpip );
+};
+
+/**
+ * Register a transport-layer protocol
+ *
+ * @v protocol          Transport-layer protocol
+ */
+#define TCPIP_PROTOCOL( protocol ) \
+        struct tcpip_protocol protocol __table ( tcpip_protocols, 01 )
+
+#define TCPIP_NET_PROTOCOL( protocol ) \
+        struct tcpip_net_protocol protocol __table ( tcpip_net_protocols, 01 )
+
+extern void trans_rx ( struct pk_buff *pkb, uint8_t trans_proto, 
+		       struct in_addr *src, struct in_addr *dest );
+
+extern int trans_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip, 
+		      struct sockaddr *dest );
+
+extern uint16_t calc_chksum ( void *data, size_t len );
+
+extern struct tcpip_protocol * find_tcpip_protocol ( uint8_t trans_proto );
+extern struct tcpip_net_protocol * find_tcpip_net_protocol ( sa_family_t sa_family );
+
+#endif /* _GPXE_INTERFACE_H */

src/include/gpxe/udp.h

@@ -74,6 +74,11 @@ struct udp_connection {
  */
 static LIST_HEAD ( udp_conns );
 
+/**
+ * UDP protocol
+ */
+extern struct tcpip_protocol udp_protocol;
+
 /**
  * Functions provided to the application layer
  */