#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <byteswap.h>
#include <errno.h>
#include <gpxe/tcpip.h>
#include <gpxe/pkbuff.h>
#include <gpxe/netdevice.h>
#include <gpxe/udp.h>
/** @file
*
* UDP protocol
*/
struct tcpip_protocol udp_protocol;
/**
* List of registered UDP connections
*/
static LIST_HEAD ( udp_conns );
/**
* Bind UDP connection to local port
*
* @v conn UDP connection
* @v local_port Local port, in network byte order
* @ret rc Return status code
*/
int udp_bind ( struct udp_connection *conn, uint16_t local_port ) {
struct udp_connection *existing;
list_for_each_entry ( existing, &udp_conns, list ) {
if ( existing->local_port == local_port )
return -EADDRINUSE;
}
conn->local_port = local_port;
return 0;
}
/**
* Open a local port
*
* @v conn UDP connection
* @v local_port Local port, in network byte order, or zero
* @ret rc Return status code
*
* Opens the UDP connection and binds to a local port. If no local
* port is specified, the first available port will be used.
*/
int udp_open ( struct udp_connection *conn, uint16_t local_port ) {
static uint16_t try_port = 1024;
int rc;
/* If no port specified, find the first available port */
if ( ! local_port ) {
for ( ; try_port ; try_port++ ) {
if ( try_port < 1024 )
continue;
if ( udp_open ( conn, htons ( try_port ) ) == 0 )
return 0;
}
return -EADDRINUSE;
}
/* Attempt bind to local port */
if ( ( rc = udp_bind ( conn, local_port ) ) != 0 )
return rc;
/* Add to UDP connection list */
list_add ( &conn->list, &udp_conns );
DBG ( "UDP opened %p on port %d\n", conn, ntohs ( local_port ) );
return 0;
}
/**
* Close a UDP connection
*
* @v conn UDP connection
*/
void udp_close ( struct udp_connection *conn ) {
list_del ( &conn->list );
DBG ( "UDP closed %p\n", conn );
}
/**
* User request to send data via a UDP connection
*
* @v conn UDP connection
*
* This function allocates buffer space and invokes the function's senddata()
* callback. The callback may use the buffer space
*/
int udp_senddata ( struct udp_connection *conn ) {
int rc;
conn->tx_pkb = alloc_pkb ( UDP_MAX_TXPKB );
if ( conn->tx_pkb == NULL ) {
DBG ( "UDP %p cannot allocate packet buffer of length %d\n",
conn, UDP_MAX_TXPKB );
return -ENOMEM;
}
pkb_reserve ( conn->tx_pkb, UDP_MAX_HLEN );
rc = conn->udp_op->senddata ( conn, conn->tx_pkb->data,
pkb_available ( conn->tx_pkb ) );
if ( conn->tx_pkb )
free_pkb ( conn->tx_pkb );
return rc;
}
/**
* Transmit data via a UDP connection to a specified address
*
* @v conn UDP connection
* @v peer Destination address
* @v data Data to send
* @v len Length of data
* @ret rc Return status code
*
* This function fills up the UDP headers and sends the data. It may
* be called only from within the context of an application's
* senddata() method; if the application wishes to send data it must
* call udp_senddata() and wait for its senddata() method to be
* called.
*/
int udp_sendto ( struct udp_connection *conn, struct sockaddr_tcpip *peer,
const void *data, size_t len ) {
struct udp_header *udphdr;
struct pk_buff *pkb;
/* Take ownership of packet buffer back from the
* udp_connection structure.
*/
pkb = conn->tx_pkb;
conn->tx_pkb = NULL;
/* Avoid overflowing TX buffer */
if ( len > pkb_available ( pkb ) )
len = pkb_available ( pkb );
/* Copy payload */
memmove ( pkb_put ( pkb, len ), data, len );
/*
* Add the UDP header
*
* Covert all 16- and 32- bit integers into network btye order before
* sending it over the network
*/
udphdr = pkb_push ( pkb, sizeof ( *udphdr ) );
udphdr->dest_port = peer->st_port;
udphdr->source_port = conn->local_port;
udphdr->len = htons ( pkb_len ( pkb ) );
udphdr->chksum = 0;
udphdr->chksum = tcpip_chksum ( udphdr, sizeof ( *udphdr ) + len );
/* Dump debugging information */
DBG ( "UDP %p transmitting %p+%#zx len %#x src %d dest %d "
"chksum %#04x\n", conn, pkb->data,
pkb_len ( pkb ), ntohs ( udphdr->len ),
ntohs ( udphdr->source_port ), ntohs ( udphdr->dest_port ),
ntohs ( udphdr->chksum ) );
/* Send it to the next layer for processing */
return tcpip_tx ( pkb, &udp_protocol, peer );
}
/**
* Transmit data via a UDP connection
*
* @v conn UDP connection
* @v data Data to send
* @v len Length of data
* @ret rc Return status code
*
* This function fills up the UDP headers and sends the data. It may
* be called only from within the context of an application's
* senddata() method; if the application wishes to send data it must
* call udp_senddata() and wait for its senddata() method to be
* called.
*/
int udp_send ( struct udp_connection *conn, const void *data, size_t len ) {
return udp_sendto ( conn, &conn->peer, data, len );
}
/**
* Process a received packet
*
* @v pkb Packet buffer
* @v st_src Partially-filled source address
* @v st_dest Partially-filled destination address
* @ret rc Return status code
*/
static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
struct sockaddr_tcpip *st_dest ) {
struct udp_header *udphdr = pkb->data;
struct udp_connection *conn;
unsigned int ulen;
uint16_t chksum;
int rc;
/* Sanity check */
if ( pkb_len ( pkb ) < sizeof ( *udphdr ) ) {
DBG ( "UDP received underlength packet %p+%#zx\n",
pkb->data, pkb_len ( pkb ) );
rc = -EINVAL;
goto done;
}
/* Dump debugging information */
DBG ( "UDP received %p+%#zx len %#x src %d dest %d chksum %#04x\n",
pkb->data, pkb_len ( pkb ), ntohs ( udphdr->len ),
ntohs ( udphdr->source_port ), ntohs ( udphdr->dest_port ),
ntohs ( udphdr->chksum ) );
/* Check length and trim any excess */
ulen = ntohs ( udphdr->len );
if ( ulen > pkb_len ( pkb ) ) {
DBG ( "UDP received truncated packet %p+%#zx\n",
pkb->data, pkb_len ( pkb ) );
rc = -EINVAL;
goto done;
}
pkb_unput ( pkb, ( pkb_len ( pkb ) - ulen ) );
/* Verify the checksum */
#warning "Don't we need to take the pseudo-header into account here?"
#if 0
chksum = tcpip_chksum ( pkb->data, pkb_len ( pkb ) );
if ( chksum != 0xffff ) {
DBG ( "Bad checksum %#x\n", chksum );
rc = -EINVAL;
goto done;
}
#endif
/* Complete the socket addresses */
st_src->st_port = udphdr->source_port;
st_dest->st_port = udphdr->dest_port;
/* Demux the connection */
list_for_each_entry ( conn, &udp_conns, list ) {
if ( conn->local_port &&
( conn->local_port != udphdr->dest_port ) ) {
/* Bound to local port and local port doesn't match */
continue;
}
/* Strip off the UDP header */
pkb_pull ( pkb, sizeof ( *udphdr ) );
DBG ( "UDP delivering to %p\n", conn );
/* Call the application's callback */
rc = conn->udp_op->newdata ( conn, pkb->data, pkb_len( pkb ),
st_src, st_dest );
goto done;
}
DBG ( "No UDP connection listening on port %d\n",
ntohs ( udphdr->dest_port ) );
rc = 0;
done:
free_pkb ( pkb );
return rc;
}
struct tcpip_protocol udp_protocol = {
.name = "UDP",
.rx = udp_rx,
.tcpip_proto = IP_UDP,
.csum_offset = 6,
};
TCPIP_PROTOCOL ( udp_protocol );
