net_udp.c

MIPS下的boottloader yamon 的源代码

/************************************************************************
 *
 *      NET_UDP.c
 *
 *      The 'NET_UDP' module implements the UDP layer of the IP-protocols
 *      and and it provides services to send and receive
 *      UDP datagrams via service access points, which are linked
 *      with the 'port'-field of the UDP-header.
 *
 *
 * ######################################################################
 *
 * Copyright (c) 1999-2000 MIPS Technologies, Inc. All rights reserved. 
 * 
 * Unpublished rights reserved under the Copyright Laws of the United States of 
 * America. 
 * 
 * This document contains information that is proprietary to MIPS Technologies, 
 * Inc. ("MIPS Technologies"). Any copying, modifying or use of this information 
 * (in whole or in part) which is not expressly permitted in writing by MIPS 
 * Technologies or a contractually-authorized third party is strictly 
 * prohibited. At a minimum, this information is protected under unfair 
 * competition laws and the expression of the information contained herein is 
 * protected under federal copyright laws. Violations thereof may result in 
 * criminal penalties and fines. 
 * MIPS Technologies or any contractually-authorized third party reserves the 
 * right to change the information contained in this document to improve 
 * function, design or otherwise. MIPS Technologies does not assume any 
 * liability arising out of the application or use of this information. Any 
 * license under patent rights or any other intellectual property rights owned 
 * by MIPS Technologies or third parties shall be conveyed by MIPS Technologies 
 * or any contractually-authorized third party in a separate license agreement 
 * between the parties. 
 * The information contained in this document constitutes one or more of the 
 * following: commercial computer software, commercial computer software 
 * documentation or other commercial items. If the user of this information, or 
 * any related documentation of any kind, including related technical data or 
 * manuals, is an agency, department, or other entity of the United States 
 * government ("Government"), the use, duplication, reproduction, release, 
 * modification, disclosure, or transfer of this information, or any related 
 * documentation of any kind, is restricted in accordance with Federal 
 * Acquisition Regulation 12.212 for civilian agencies and Defense Federal 
 * Acquisition Regulation Supplement 227.7202 for military agencies. The use of 
 * this information by the Government is further restricted in accordance with 
 * the terms of the license agreement(s) and/or applicable contract terms and 
 * conditions covering this information from MIPS Technologies or any 
 * contractually-authorized third party. 
 *
 ************************************************************************/


/************************************************************************
 *      Include files
 ************************************************************************/

#include <string.h>
#include <stdio.h>
#include <sysdefs.h>
#include <syserror.h>
#include <sysdev.h>
#include <syscon_api.h>

/* net stuff */
#include <net_api.h>
#include "net.h"
#include "net_mac.h"
#include "net_ip.h"
#include "net_udp.h"


/************************************************************************
 *      Definitions
 ************************************************************************/


/************************************************************************
 *      Public variables
 ************************************************************************/


/************************************************************************
 *      Static variables
 ************************************************************************/

/* Global state of UDP */
static UINT32 NET_UDP_state = UDP_STATE_CLOSED ;

/* The IP SP-handle, returned by 'IP-open' */
static UINT32 ip_sp_hd ;

/* UDP SAP table */
static t_udp_sap_context sap_context[UDP_SAP_COUNT] ;

/* UDP SAP allocation variable, keeping a simple counter
   to be used for allocating unique 'port' numbers
   in UDP-'open'                                      */
static UINT16 udp_sap_next ;


/************************************************************************
 *      Static function prototypes
 ************************************************************************/

/************************************************************************
 *
 *                          NET_UDP_receive
 *  Description :
 *  -------------
 *  This function is registered in the IP-module and linked with the
 *  IP-protocol = '17', to let the IP call us back with a reference
 *  to the received frame, containing an UDP-frame.
 *  In this function the UDP-header will be validated and
 *  the any opened UDP-SAP will be checked to call a user registered
 *  receive handler.
 *
 *
 *
 *  Parameters :
 *  ------------
 *  'src_ip_adr':  sender's IP-address (BE-format)
 *  'src_mac_adr': sender's MAC-address
 *  'length':      length of received ethernet frame
 *  'data':        pointer for received ethernet frame (in driver's space)
 *
 *
 *  Return values :
 *  ---------------
 *  'OK'
 *
 ************************************************************************/
static
UINT32 NET_UDP_receive( UINT32     src_ip_adr,
                        t_mac_addr *src_mac_adr,
                        UINT32     length,
                        UINT8      *data    ) ;




/************************************************************************
 *      Implementation : Public functions
 ************************************************************************/

/************************************************************************
 *
 *                          NET_UDP_init
 *  Description :
 *  -------------
 *  Initialize the UDP module.
 *
 *
 *  Parameters :
 *  ------------
 *  -
 *
 *
 *  Return values :
 *  ---------------
 *  'OK'(=0), successfull initialization
 *
 ************************************************************************/
UINT32 NET_UDP_init(  void )
{
    UINT32 rcode ;
    int    i ;

    /* initialize UDP SAP table */
    for ( i = 0; i <IP_SAP_COUNT ; i++)
    {
        sap_context[i].sap_state   = UDP_SAP_STATE_CLOSED ;
        sap_context[i].sap         = UDP_SAP_UNDEFINED ;
        sap_context[i].usr_receive = NULL ;
    }

    /* first unique SAP to be used at 'open' */
    udp_sap_next = UDP_SAP_RESERVED_UPPER + 1 ;

    /* register our receive handler */
    IF_ERROR( (rcode),
              (NET_IP_open( IP_SAP_UDP,
                            NET_UDP_receive,
                            &ip_sp_hd) ) )

    /* UDP-module has now been initialized and opened for service */
    NET_UDP_state = UDP_STATE_OPEN ;

    return(OK) ;
}


/************************************************************************
 *
 *                          NET_UDP_open
 *  Description :
 *  -------------
 *  Allocate a UDP-SAP and register user context.
 *
 *
 *  Parameters :
 *  ------------
 *  'sap_id',          IN,    value of UDP-'port' (our) to bind for.
 *                            If the value is 'undefined'(=0), the
 *                            UDP-module allocates a unique port.
 *  'usr_receive',     IN,    user-receive function to be registered
 *  'sp_hd',           OUT,   handle of UDP to be used by user by call
 *                            of 'send' or 'close'
 *
 *  Return values :
 *  ---------------
 *  'ERROR_NET_UDP_FATAL_STATE'      A fatal state has been detected in UDP.
 *  'ERROR_NET_UDP_NOT_INITIALIZED'  UDP-'init' has not been called.
 *  'OK'(=0),
 *
 *
 ************************************************************************/
UINT32 NET_UDP_open( UINT16            sap_id,     /* port in BE-format */
                     t_udp_usr_receive usr_receive,
                     UINT32            *sp_hd )
{
    UINT32  rcode = OK ;
    int     i ;

    switch (NET_UDP_state)
    {
        case UDP_STATE_CLOSED:
                rcode = ERROR_NET_UDP_NOT_INITIALIZED ;
            break;

        case UDP_STATE_OPEN:
                /* Validate or find unique sap */
                if ( sap_id == UDP_SAP_UNDEFINED )
                {
                    sap_id = CPU_TO_BE16( udp_sap_next ) ;
                    udp_sap_next++ ;
                    if (udp_sap_next == 0) 
                    {
                        udp_sap_next = UDP_SAP_RESERVED_UPPER + 1 ;
                    }
                }
                for ( i = 0; i <UDP_SAP_COUNT ; i++)
                {
                    if ( (sap_context[i].sap_state == UDP_STATE_OPEN) &&
                         (sap_context[i].sap       == sap_id) )
                    {
                        /* we have found an unuseable SAP */
                        return( ERROR_NET_UDP_SAP_INUSE ) ;
                    }
                }

                /* allocate a free UDP SAP table entry */
                for ( i = 0; i <UDP_SAP_COUNT ; i++)
                {
                    if ( sap_context[i].sap_state == UDP_SAP_STATE_CLOSED )
                    {
                        /* save SAP context in allocated entry */
                        sap_context[i].sap_state   = UDP_SAP_STATE_OPEN ;
                        sap_context[i].sap         = sap_id ;
                        sap_context[i].usr_receive = usr_receive ;
                        *sp_hd                     = i ;
                        return( OK ) ;
                    }
                }
                rcode = ERROR_NET_UDP_NO_FREE_SAP ;
            break;

        default:
                /* we should never arrive here */
                rcode = ERROR_NET_UDP_FATAL_STATE ;
            break;

    }
    return( rcode ) ;
}