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
  */

src/net/ipv4.c

@@ -12,7 +12,7 @@
 #include <gpxe/netdevice.h>
 #include "uip/uip.h"
 #include <gpxe/ip.h>
-#include <gpxe/interface.h>
+#include <gpxe/tcpip_if.h>
 
 /** @file
  *
@@ -103,6 +103,7 @@ void del_ipv4_address ( struct net_device *netdev ) {
  * @v iphdr	IPv4 header
  */
 static void ipv4_dump ( struct iphdr *iphdr __unused ) {
+
 	DBG ( "IP4 header at %p+%zx\n", iphdr, sizeof ( *iphdr ) );
 	DBG ( "\tVersion = %d\n", ( iphdr->verhdrlen & IP_MASK_VER ) / 16 );
 	DBG ( "\tHeader length = %d\n", iphdr->verhdrlen & IP_MASK_HLEN );
@@ -120,12 +121,19 @@ static void ipv4_dump ( struct iphdr *iphdr __unused ) {
 
 /**
  * Complete the transport-layer checksum
+ *
+ * @v pkb	Packet buffer
+ * @v tcpip	Transport-layer protocol
+ *
+ * This function calculates the tcpip 
  */
-void ipv4_tx_csum ( struct pk_buff *pkb, uint8_t trans_proto ) {
+void ipv4_tx_csum ( struct pk_buff *pkb, struct tcpip_protocol *tcpip ) {
 
 	struct iphdr *iphdr = pkb->data;
 	struct ipv4_pseudo_header pshdr;
-	void *csum_offset = iphdr + sizeof ( *iphdr ) + ( trans_proto == IP_UDP ? 6 : 16 );
+	void *csum_offset = iphdr + sizeof ( *iphdr ) + tcpip->csum_offset;
+	uint16_t partial_csum = *( ( uint16_t* ) csum_offset );
+	uint16_t csum;
 
 	/* Calculate pseudo header */
 	pshdr.src = iphdr->src;
@@ -135,14 +143,19 @@ void ipv4_tx_csum ( struct pk_buff *pkb, uint8_t trans_proto ) {
 	pshdr.len = htons ( pkb_len ( pkb ) - sizeof ( *iphdr ) );
 
 	/* Update the checksum value */
-	*( ( uint16_t* ) csum_offset ) = *( ( uint16_t* ) csum_offset ) + calc_chksum ( &pshdr, IP_PSHLEN );
+	csum = partial_csum + calc_chksum ( &pshdr, sizeof ( pshdr ) );
+	memcpy ( csum_offset, &csum, 2 );
 }
 
 /**
  * Calculate the transport-layer checksum while processing packets
  */
-uint16_t ipv4_rx_csum ( struct pk_buff *pkb __unused, uint8_t trans_proto __unused ) {
-	/** This function needs to be implemented. Until then, it will return 0xffffffff every time */
+uint16_t ipv4_rx_csum ( struct pk_buff *pkb __unused,
+			uint8_t trans_proto __unused ) {
+	/** 
+	 * This function needs to be implemented. Until then, it will return
+	 * 0xffffffff every time
+	 */
 	return 0xffff;
 }
 
@@ -222,13 +235,14 @@ int ipv4_uip_tx ( struct pk_buff *pkb ) {
  * Transmit IP packet (without uIP)
  *
  * @v pkb		Packet buffer
- * @v trans_proto	Transport-layer protocol number
+ * @v tcpip		Transport-layer protocol
  * @v dest		Destination network-layer address
  * @ret rc		Status
  *
  * This function expects a transport-layer segment and prepends the IP header
  */
-int ipv4_tx ( struct pk_buff *pkb, uint16_t trans_proto, struct in_addr *dest ) {
+int ipv4_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip,
+	      struct in_addr *dest ) {
 	struct iphdr *iphdr = pkb_push ( pkb, sizeof ( *iphdr ) );
 	struct ipv4_miniroute *miniroute;
 	struct net_device *netdev = NULL;
@@ -244,7 +258,7 @@ int ipv4_tx ( struct pk_buff *pkb, uint16_t trans_proto, struct in_addr *dest )
 	iphdr->ident = htons ( next_ident++ );
 	iphdr->frags = 0;
 	iphdr->ttl = IP_TTL;
-	iphdr->protocol = trans_proto;
+	iphdr->protocol = tcpip->trans_proto;
 
 	/* Copy destination address */
 	iphdr->dest = *dest;
@@ -280,7 +294,7 @@ int ipv4_tx ( struct pk_buff *pkb, uint16_t trans_proto, struct in_addr *dest )
 	}
 
 	/* Calculate the transport layer checksum */
-	ipv4_tx_csum ( pkb, trans_proto );
+	ipv4_tx_csum ( pkb, tcpip );
 
 	/* Calculate header checksum, in network byte order */
 	iphdr->chksum = 0;
@@ -477,6 +491,14 @@ struct net_protocol ipv4_protocol = {
 
 NET_PROTOCOL ( ipv4_protocol );
 
+/** IPv4 TCPIP net protocol */
+struct tcpip_net_protocol ipv4_tcpip_protocol = {
+	.net_protocol = &ipv4_protocol,
+	.tx_csum = ipv4_tx_csum,
+};
+
+TCPIP_NET_PROTOCOL ( ipv4_tcpip_protocol );
+
 /** IPv4 ARP protocol */
 struct arp_net_protocol ipv4_arp_protocol = {
 	.net_protocol = &ipv4_protocol,

src/net/tcpip_if.c

@@ -0,0 +1,136 @@
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <malloc.h>
+#include <byteswap.h>
+#include <gpxe/in.h>
+#include <gpxe/ip.h>
+#include <gpxe/pkbuff.h>
+#include <gpxe/tables.h>
+#include <gpxe/netdevice.h>
+#include <gpxe/tcpip_if.h>
+
+/** @file
+ *
+ * Transport-network layer interface
+ *
+ * This file contains functions and utilities for the transport-network layer interface
+ */
+
+/** Registered network-layer protocols that support TCPIP */
+static struct tcpip_net_protocol tcpip_net_protocols[0] __table_start ( tcpip_net_protocols );
+static struct tcpip_net_protocol tcpip_net_protocols_end[0] __table_end ( tcpip_net_protocols );
+
+struct tcpip_protocol;
+
+/** Registered transport-layer protocols that support TCPIP */
+static struct tcpip_protocol tcpip_protocols[0] __table_start ( tcpip_protocols );
+static struct tcpip_protocol tcpip_protocols_end[0] __table_end ( tcpip_protocols );
+
+/** Identify TCPIP network-layer protocol
+ *
+ * @v sa_family	 Network address family
+ * @ret tcpip	   Protocol supporting TCPIP, or NULL
+ */
+static struct tcpip_net_protocol * tcpip_find_protocol ( sa_family_t sa_family ) {
+	struct tcpip_net_protocol *tcpip_net;
+
+	for ( tcpip_net = tcpip_net_protocols; 
+		tcpip_net < tcpip_net_protocols_end; ++tcpip_net ) {
+		if ( tcpip_net->sa_family == sa_family ) {
+			return tcpip_net;
+		}
+	}
+	return NULL;
+}
+
+/** Identify TCPIP transport-layer protocol
+ *
+ * @v trans_proto	Transport-layer protocol number, IP_XXX
+ * @ret tcpip_protocol	Transport-layer protocol, or NULL
+ */
+struct tcpip_protocol* find_tcpip_protocol ( uint8_t trans_proto ) {
+	struct tcpip_protocol *tcpip;
+
+	for ( tcpip = tcpip_protocols; tcpip <= tcpip_protocols_end; 
+		++tcpip ) {
+		if ( tcpip->trans_proto == trans_proto ) {
+			return tcpip;
+		}
+	}
+	return NULL;
+}
+
+/** Process a received packet
+ *
+ * @v pkb		Packet buffer
+ * @v trans_proto	Transport-layer protocol number
+ * @v src		Source network-layer address
+ * @v dest		Destination network-layer address
+ *
+ * This function expects a transport-layer segment from the network-layer
+ */
+void trans_rx ( struct pk_buff *pkb, uint8_t trans_proto, struct in_addr *src,
+		struct in_addr *dest ) {
+	struct tcpip_protocol *tcpip;
+
+	/* Identify the transport layer protocol */
+	for ( tcpip = tcpip_protocols; tcpip <= tcpip_protocols_end; ++tcpip ) {
+		if ( tcpip->trans_proto == trans_proto ) {
+			DBG ( "Packet sent to %s module", tcpip->name );
+			tcpip->rx ( pkb, src, dest );
+		}
+	}
+}
+
+/** Transmit a transport-layer segment
+ *
+ * @v pkb		Packet buffer
+ * @v trans_proto	Transport-layer protocol
+ * @v sock		Destination socket address
+ * @ret			Status
+ */
+int trans_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip,
+	       struct sockaddr *sock ) {
+
+	/* Identify the network layer protocol and send it using xxx_tx() */
+	switch ( sock->sa_family ) {
+	case AF_INET: /* IPv4 network family */
+		return ipv4_tx ( pkb, tcpip, &sock->sin.sin_addr );
+	case AF_INET6: /* IPv6 network family */
+		return ipv6_tx ( pkb, tcpip, &sock->sin6.sin6_addr );
+	}
+	DBG ( "Network family %d not supported", sock->sa_family );
+	return -EAFNOSUPPORT;
+}
+
+/**
+ * Calculate internet checksum
+ *
+ * @v data      Pointer to the data
+ * @v len       Length of data to be checksummed
+ * @ret chksum  16 bit internet checksum
+ *
+ * This function calculates the internet checksum (refer RFC1071) for "len"
+ * bytes beginning at the location "data"
+ */
+uint16_t calc_chksum ( void *data, size_t len ) {
+	register long sum = 0;
+	uint16_t checksum;
+	unsigned short *temp;
+	while ( len > 1 ) {
+		temp = (unsigned short*) data++;
+		sum += *temp;
+		len -= 2;
+	}
+	if ( len > 0 ) {
+		sum += *(unsigned char *)data;
+	}
+	while ( sum >> 16 ) {
+		sum = ( sum & 0xffff ) + ( sum >> 16 );
+	}
+	checksum = ~sum;
+	return checksum;
+}
+
+

src/net/udp.c

@@ -6,11 +6,12 @@
 #include <errno.h>
 #include <gpxe/in.h>
 #include <gpxe/ip.h>
+#include <gpxe/ip6.h>
 #include <gpxe/udp.h>
 #include <gpxe/init.h>
 #include <gpxe/pkbuff.h>
 #include <gpxe/netdevice.h>
-#include <gpxe/interface.h>
+#include <gpxe/tcpip_if.h>
 
 /** @file
  *
@@ -149,7 +150,7 @@ int udp_send ( struct udp_connection *conn, const void *data, size_t len ) {
 	udp_dump ( udphdr );
 
 	/* Send it to the next layer for processing */
-	return trans_tx ( conn->tx_pkb, IP_UDP, sock );
+	return trans_tx ( conn->tx_pkb, &udp_protocol, sock );
 }
 
 /**
@@ -268,10 +269,11 @@ void udp_rx ( struct pk_buff *pkb, struct in_addr *src_net_addr __unused,
 	conn->udp_op->newdata ( conn, pkb->data, ulen - sizeof ( *udphdr ) );
 }
 
-struct trans_protocol udp_protocol  = {
+struct tcpip_protocol udp_protocol  = {
 	.name = "UDP",
 	.rx = udp_rx,
 	.trans_proto = IP_UDP,
+	.csum_offset = 6,
 };
 
-TRANS_PROTOCOL ( udp_protocol );
+TCPIP_PROTOCOL ( udp_protocol );