slpfunc.c

这是有名的＜＜嵌入式系统TCP/IP应用层协议＞＞,M.Tim Jones 著

/*
 *  Embedded SLP Message Functions
 *
 *  ./software/ch10/emslp/slpfunc.c
 *
 *  [e-mail]
 *
 */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "manip.h"
#include "slppriv.h"

#define SLP_VERSION	2

/*
 *  slpCreateHeader()
 *
 *  Populate an SLP message header with default and user-defined values.
 *
 */

void slpCreateHeader( slpMsgType *slpMsg, 
                      int type, 
                      const char *lang, 
                      uint8_t flags )
{
  int len = strlen(lang);

  extern int archType;

  if ((slpMsg == NULL) || (lang == NULL)) return;

  bzero( (void *)slpMsg, sizeof(slpMsgType) );

  if (archType == MULTICAST_ARCH) flags |= REQUEST_MCAST;

  emitByte(slpMsg, SLP_VERSION);
  emitByte(slpMsg, (unsigned char)type);
  emitShort(slpMsg, 0); emitByte(slpMsg, 0); // Fake length
  emitByte(slpMsg, flags);
  emitShort(slpMsg, 0);                      // Rsvd / Next Ext Offset
  emitShort(slpMsg, 0);                      // Next Offset Continued
  emitShort(slpMsg, 0);                      // Fake XID
  emitShort(slpMsg, len);                    // Language Tag Length
  emitString(slpMsg, lang);                  // Language Tag
}


/*
 *  setSlpHeaderLength()
 *
 *  Set the length of an SLP message in the SLP header.
 *
 */

void setSlpHeaderLength( slpMsgType *slpMsg )
{
  if (slpMsg == NULL) return;

  /* Load the message length into the slp message buffer */
  slpMsg->buffer[2] = (unsigned char)((slpMsg->len >> 16) & 0xff);
  slpMsg->buffer[3] = (unsigned char)((slpMsg->len >> 8)  & 0xff);
  slpMsg->buffer[4] = (unsigned char)((slpMsg->len)       & 0xff);
}


/*
 *  setSlpXID()
 *
 *  Set the XID of an SLP message in the SLP header.
 *
 */

void setSlpXID( slpMsgType *slpMsg, uint16_t xid )
{
  if (slpMsg == NULL) return;

  slpMsg->buffer[10] = (unsigned char)((xid >> 8) & 0xff);
  slpMsg->buffer[11] = (unsigned char)((xid)      & 0xff);
}


/*
 *  slpPrintMessage()
 *
 *  Debug function to emit an SLP message.
 *
 */

void slpPrintMessage( slpMsgType *slpMsg )
{
#ifdef SLP_DEBUG
  int i, j, start=0;

  if (slpMsg == NULL) return;

  for (i = 0 ; i < slpMsg->len ; i++) {
    if ((i % 16) == 0) {
      if (i != 0) {
        start = i-16;
        printf("  ");
        for (j = start ; j < i ; j++) {
          printf("%c", (isprint(slpMsg->buffer[j]) ? slpMsg->buffer[j] : '.'));
        }
      }
      printf("\n  %04x : ", i);
    }
    printf("%02x ", (unsigned char)slpMsg->buffer[i]);
  }

  if ((i % 16) != 0) {
      for (j = 0 ; j < (16 - (i % 16)) ; j++) {
        printf("   ");
      }
      printf("  ");
      for (j = start+16 ; j < i ; j++) {
        printf("%c", (isprint(slpMsg->buffer[j]) ? slpMsg->buffer[j] : '.'));
      }
  }
  printf("\n");

#endif

  return;
}

/*
 *  Copyright (c) 2002 Charles River Media.  All rights reserved.
 * 
 *  Redistribution and use in source and binary forms, with or 
 *  without modification, is hereby granted without fee provided 
 *  that the following conditions are met:
 * 
 *    1.  Redistributions of source code must retain the above 
 *        copyright notice, this list of conditions and the 
 *        following disclaimer.
 *    2.  Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the 
 *        following disclaimer in the documentation and/or other 
 *        materials provided with the distribution.
 *    3.  Neither the name of Charles River Media nor the names of 
 *        its contributors may be used to endorse or promote products 
 *        derived from this software without specific prior 
 *        written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY CHARLES RIVER MEDIA AND CONTRIBUTERS 
 * 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CHARLES
 * RIVER MEDIA OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARAY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 */