created interface for transport-network interface

src/include/gpxe/interface.h

@@ -0,0 +1,90 @@
+#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 trans_protocol;
+struct tcpip_net_protocol;
+
+/** 
+ * A transport-layer protocol
+ */
+struct trans_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;
+};
+
+/**
+ * A TCPIP supporting 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 trans_proto	Transport-layer protocol number
+	 *
+	 * This function expects a network-layer datagram in its packet with the protocol field in the
+	 * IP header to be filled up. It constructs a psuedo-header using the information provided in
+	 * the IP header and computes the checksum over the pseudo-header. The checksum offset in the
+	 * transport layer header can be determined without the need of an offset value as
+	 * 
+	 * void *csum_offset = pkb->data + NET_HLEN + csum_offset ( trans_proto );
+	 * 
+	 * where,
+	 * csum_offset ( IP_TCP ) = 16
+	 * csum_offset ( IP_UDP ) = 6
+	 */
+	void ( * tx_csum ) ( struct pk_buff *pkb );
+};
+
+/**
+ * Register a transport-layer protocol
+ *
+ * @v protocol          Transport-layer protocol
+ */
+#define TRANS_PROTOCOL( protocol ) \
+        struct trans_protocol protocol __table ( trans_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, uint8_t trans_proto, struct sockaddr *dest );
+
+extern uint16_t calc_chksum ( void *data, size_t len );
+
+/** Do we need these functions? -Nikhil, 24-6-06 */
+extern struct trans_protocol * find_trans_protocol ( uint8_t trans_proto );
+extern struct tcpip_net_protocol * find_tcpip_net_protocol ( sa_family_t sa_family );
+
+#endif /* _GPXE_INTERFACE_H */

src/net/interface.c

@@ -0,0 +1,132 @@
+#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/interface.h>
+
+/** @file
+ *
+ * Transport-network layer interface
+ *
+ * This file contains functions and utilities for the transport-network layer interface
+ */
+
+/** Registered 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 trans_protocol;
+
+/** Registered transport-layer protocols */
+static struct trans_protocol trans_protocols[0] __table_start ( trans_protocols );
+static struct trans_protocol trans_protocols_end[0] __table_end ( trans_protocols );
+
+/** Identify TCPIP net 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;
+
+        for ( tcpip = tcpip_net_protocols; tcpip < tcpip_net_protocols_end; tcpip++ ) {
+                if ( tcpip->sa_family == sa_family ) {
+                        return tcpip;
+                }
+        }
+        return NULL;
+}
+
+/** Identify transport-layer protocol
+ *
+ * @v trans_proto	Transport-layer protocol number, IP_XXX
+ * @ret trans_protocol	Transport-layer protocol, or NULL
+ */
+struct trans_protocol* find_trans_protocol ( uint8_t trans_proto ) {
+        struct trans_protocol *trans_protocol;
+
+        for ( trans_protocol = trans_protocols; trans_protocol <= trans_protocols_end; ++trans_protocol ) {
+                if ( trans_protocol->trans_proto == trans_proto ) {
+                        return trans_protocol;
+                }
+        }
+        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 trans_protocol *trans_protocol;
+
+        /* Identify the transport layer protocol */
+        for ( trans_protocol = trans_protocols; trans_protocol <= trans_protocols_end; ++trans_protocol ) {
+                if ( trans_protocol->trans_proto == trans_proto ) {
+			DBG ( "Packet sent to %s module", trans_protocol->name );
+                        trans_protocol->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, uint8_t trans_proto, 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, trans_proto, &sock->sin.sin_addr );
+        case AF_INET6: /* IPv6 network family */
+                return ipv6_tx ( pkb, trans_proto, &sock->sin6.sin6_addr );
+        default:
+                DBG ( "Network family %d not supported", sock->sa_family );
+        }
+        return -EPROTONOSUPPORT;
+}
+
+/**
+ * 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;
+}
+
+