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#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <byteswap.h>
#include <gpxe/pkbuff.h>
#include <gpxe/tables.h>
#include <gpxe/tcpip.h>
/** @file
*
* Transport-network layer interface
*
* This file contains functions and utilities for the
* TCP/IP transport-network layer interface
*/
/** Registered network-layer protocols that support TCP/IP */
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 );
/** Registered transport-layer protocols that support TCP/IP */
static struct tcpip_protocol
tcpip_protocols[0]__table_start ( tcpip_protocols );
static struct tcpip_protocol
tcpip_protocols_end[0] __table_end ( tcpip_protocols );
/** Process a received TCP/IP packet
*
* @v pkb Packet buffer
* @v tcpip_proto Transport-layer protocol number
* @v st_src Partially-filled source address
* @v st_dest Partially-filled destination address
* @ret rc Return status code
*
* This function expects a transport-layer segment from the network
* layer. The network layer should fill in as much as it can of the
* source and destination addresses (i.e. it should fill in the
* address family and the network-layer addresses, but leave the ports
* and the rest of the structures as zero).
*/
int tcpip_rx ( struct pk_buff *pkb, uint8_t tcpip_proto,
struct sockaddr_tcpip *st_src,
struct sockaddr_tcpip *st_dest ) {
struct tcpip_protocol *tcpip;
/* Hand off packet to the appropriate transport-layer protocol */
for ( tcpip = tcpip_protocols; tcpip < tcpip_protocols_end; tcpip++ ) {
if ( tcpip->tcpip_proto == tcpip_proto ) {
DBG ( "TCP/IP received %s packet\n", tcpip->name );
return tcpip->rx ( pkb, st_src, st_dest );
}
}
DBG ( "Unrecognised TCP/IP protocol %d\n", tcpip_proto );
return -EPROTONOSUPPORT;
}
/** Transmit a TCP/IP packet
*
* @v pkb Packet buffer
* @v tcpip_protocol Transport-layer protocol
* @v st_dest Destination address
* @ret rc Return status code
*/
int tcpip_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip_protocol,
struct sockaddr_tcpip *st_dest ) {
struct tcpip_net_protocol *tcpip_net;
/* Hand off packet to the appropriate network-layer protocol */
for ( tcpip_net = tcpip_net_protocols ;
tcpip_net < tcpip_net_protocols_end ; tcpip_net++ ) {
if ( tcpip_net->sa_family == st_dest->st_family ) {
DBG ( "TCP/IP sending %s packet\n", tcpip_net->name );
return tcpip_net->tx ( pkb, tcpip_protocol, st_dest );
}
}
DBG ( "Unrecognised TCP/IP address family %d\n", st_dest->st_family );
return -EAFNOSUPPORT;
}
/**
* Calculate continued TCP/IP checkum
*
* @v partial Checksum of already-summed data, in network byte order
* @v data Data buffer
* @v len Length of data buffer
* @ret cksum Updated checksum, in network byte order
*
* Calculates a TCP/IP-style 16-bit checksum over the data block. The
* checksum is returned in network byte order.
*
* This function may be used to add new data to an existing checksum.
* The function assumes that both the old data and the new data start
* on even byte offsets; if this is not the case then you will need to
* byte-swap either the input partial checksum, the output checksum,
* or both. Deciding which to swap is left as an exercise for the
* interested reader.
*/
unsigned int tcpip_continue_chksum ( unsigned int partial, const void *data,
size_t len ) {
unsigned int cksum = ( ( ~partial ) & 0xffff );
unsigned int value;
unsigned int i;
for ( i = 0 ; i < len ; i++ ) {
value = * ( ( uint8_t * ) data + i );
if ( i & 1 ) {
/* Odd bytes: swap on little-endian systems */
value = be16_to_cpu ( value );
} else {
/* Even bytes: swap on big-endian systems */
value = le16_to_cpu ( value );
}
cksum += value;
if ( cksum > 0xffff )
cksum -= 0xffff;
}
return ( ( ~cksum ) & 0xffff );
}
/**
* Calculate TCP/IP checkum
*
* @v data Data buffer
* @v len Length of data buffer
* @ret cksum Checksum, in network byte order
*
* Calculates a TCP/IP-style 16-bit checksum over the data block. The
* checksum is returned in network byte order.
*/
unsigned int tcpip_chksum ( const void *data, size_t len ) {
return tcpip_continue_chksum ( 0xffff, data, len );
}
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