#include <string.h>
#include <assert.h>
#include <byteswap.h>
#include <latch.h>
#include <errno.h>
#include <gpxe/process.h>
#include <gpxe/init.h>
#include <gpxe/netdevice.h>
#include <gpxe/pkbuff.h>
#include <gpxe/ip.h>
#include <gpxe/tcp.h>
#include "uip/uip.h"
/** @file
*
* TCP protocol
*
* The gPXE TCP stack is currently implemented on top of the uIP
* protocol stack. This file provides wrappers around uIP so that
* higher-level protocol implementations do not need to talk directly
* to uIP (which has a somewhat baroque API).
*
* Basic operation is to create a #tcp_connection structure, call
* tcp_connect() and then call run_tcpip() in a loop until the
* operation has completed. The TCP stack will call the various
* methods defined in the #tcp_operations structure in order to send
* and receive data.
*
* See hello.c for a trivial example of a TCP protocol using this
* API.
*
*/
/**
* TCP transmit buffer
*
* When a tcp_operations::senddata() method is called, it is
* guaranteed to be able to use this buffer as temporary space for
* constructing the data to be sent. For example, code such as
*
* @code
*
* static void my_senddata ( struct tcp_connection *conn ) {
* int len;
*
* len = snprintf ( tcp_buffer, tcp_buflen, "FETCH %s\r\n", filename );
* tcp_send ( conn, tcp_buffer + already_sent, len - already_sent );
* }
*
* @endcode
*
* is allowed, and is probably the best way to deal with
* variably-sized data.
*
* Note that you cannot use this simple mechanism if you want to be
* able to construct single data blocks of more than #tcp_buflen
* bytes.
*/
void *tcp_buffer = uip_buf + ( 40 + UIP_LLH_LEN );
/** Size of #tcp_buffer */
size_t tcp_buflen = UIP_BUFSIZE - ( 40 + UIP_LLH_LEN );
/**
* Open a TCP connection
*
* @v conn TCP connection
*
* This sets up a new TCP connection to the remote host specified in
* tcp_connection::sin.
*/
void tcp_connect ( struct tcp_connection *conn ) {
struct uip_conn *uip_conn;
u16_t ipaddr[2];
assert ( conn->sin.sin_addr.s_addr != 0 );
assert ( conn->sin.sin_port != 0 );
assert ( conn->tcp_op != NULL );
assert ( sizeof ( uip_conn->appstate ) == sizeof ( conn ) );
* ( ( uint32_t * ) ipaddr ) = conn->sin.sin_addr.s_addr;
uip_conn = uip_connect ( ipaddr, conn->sin.sin_port );
#warning "Use linked lists so that uip_connect() cannot fail"
assert ( uip_conn != NULL );
*( ( void ** ) uip_conn->appstate ) = conn;
}
/**
* Send data via a TCP connection
*
* @v conn TCP connection
* @v data Data to send
* @v len Length of data
*
* Data will be automatically limited to the current TCP window size.
*
* If retransmission is required, the connection's
* tcp_operations::senddata() method will be called again in order to
* regenerate the data.
*/
void tcp_send ( struct tcp_connection *conn __unused,
const void *data, size_t len ) {
assert ( conn = *( ( void ** ) uip_conn->appstate ) );
if ( len > tcp_buflen )
len = tcp_buflen;
memmove ( tcp_buffer, data, len );
uip_send ( tcp_buffer, len );
}
/**
* Close a TCP connection
*
* @v conn TCP connection
*/
void tcp_close ( struct tcp_connection *conn __unused ) {
assert ( conn = *( ( void ** ) uip_conn->appstate ) );
uip_close();
}
/**
* uIP TCP application call interface
*
* This is the entry point of gPXE from the point of view of the uIP
* protocol stack. This function calls the appropriate methods from
* the connection's @tcp_operations table in order to process received
* data, transmit new data etc.
*/
void uip_tcp_appcall ( void ) {
struct tcp_connection *conn = *( ( void ** ) uip_conn->appstate );
struct tcp_operations *op = conn->tcp_op;
if ( op->closed ) {
if ( uip_aborted() )
op->closed ( conn, -ECONNABORTED );
if ( uip_timedout() )
op->closed ( conn, -ETIMEDOUT );
if ( uip_closed() )
op->closed ( conn, 0 );
}
if ( uip_connected() && op->connected )
op->connected ( conn );
if ( uip_acked() && op->acked )
op->acked ( conn, uip_conn->len );
if ( uip_newdata() && op->newdata )
op->newdata ( conn, ( void * ) uip_appdata, uip_len );
if ( ( uip_rexmit() || uip_newdata() || uip_acked() ||
uip_connected() || uip_poll() ) && op->senddata )
op->senddata ( conn );
}
/* Present here to allow everything to link. Will go into separate
* udp.c file
*/
void uip_udp_appcall ( void ) {
}
/**
* Perform periodic processing of all TCP connections
*
* This allows TCP connections to retransmit data if necessary.
*/
static void tcp_periodic ( void ) {
struct pk_buff *pkb;
int i;
for ( i = 0 ; i < UIP_CONNS ; i++ ) {
uip_periodic ( i );
if ( uip_len > 0 ) {
pkb = alloc_pkb ( uip_len + MAX_LL_HEADER_LEN);
if ( ! pkb )
continue;
pkb_reserve ( pkb, MAX_LL_HEADER_LEN );
pkb_put ( pkb, uip_len );
memcpy ( pkb->data, uip_buf, uip_len );
pkb->net_protocol = &ipv4_protocol;
net_transmit ( pkb );
}
}
}
/**
* Single-step the TCP stack
*
* @v process TCP process
*
* This calls tcp_periodic() at regular intervals.
*/
static void tcp_step ( struct process *process ) {
static unsigned long timeout = 0;
if ( currticks() > timeout ) {
timeout = currticks() + ( TICKS_PER_SEC / 10 );
tcp_periodic ();
}
schedule ( process );
}
/** TCP stack process */
static struct process tcp_process = {
.step = tcp_step,
};
/** Initialise the TCP stack */
static void init_tcp ( void ) {
schedule ( &tcp_process );
}
INIT_FN ( INIT_PROCESS, init_tcp, NULL, NULL );
