tcp_ni.c

用于嵌入式系统的TCP/IP协议栈

/***********************************************************************/
/*                                                                     */
/*   Module:  tcp_ni.c                                                 */
/*   Release: 2001.3                                                   */
/*   Version: 2000.0                                                   */
/*   Purpose: tcpAddNi()/tcpDelNi() implementations                    */
/*                                                                     */
/*---------------------------------------------------------------------*/
/*                                                                     */
/*               Copyright 2000, Blunk Microsystems                    */
/*                      ALL RIGHTS RESERVED                            */
/*                                                                     */
/*   Licensees have the non-exclusive right to use, modify, or extract */
/*   this computer program for software development at a single site.  */
/*   This program may be resold or disseminated in executable format   */
/*   only. The source code may not be redistributed or resold.         */
/*                                                                     */
/*                                                                     */
/***********************************************************************/
#include "tcp_ipp.h"
#include "ip/ip.h"
#include <string.h>

/***********************************************************************/
/* Local Function Definitions                                          */
/***********************************************************************/

/***********************************************************************/
/* NiBorrowAddr: Searches for available address to borrow              */
/*                                                                     */
/*     Returns: Either 0 or a borrowed IP address                      */
/*                                                                     */
/***********************************************************************/
ui32 NiBorrowAddr(void)
{
  Ni *ni;

  /*-------------------------------------------------------------------*/
  /* Search network interface list, skipping local interface.          */
  /*-------------------------------------------------------------------*/
  for (ni = Net.Local.next; ni; ni = ni->next)
  {
    /*-----------------------------------------------------------------*/
    /* If address assigned and not borrowed, return its value.         */
    /*-----------------------------------------------------------------*/
    if (ni->ip_addr && ((ni->flags & NIF_BORROWED) == FALSE))
      return ni->ip_addr;
  }

  /*-------------------------------------------------------------------*/
  /* Return 0 if no address available to borrow.                       */
  /*-------------------------------------------------------------------*/
  return 0;
}

/***********************************************************************/
/*     NiRtAdd: Add routes for a network interface                     */
/*                                                                     */
/*       Input: ni = pointer to network interface structure            */
/*                                                                     */
/*        Note: Must be called with internals semaphore held           */
/*     Returns: -1 if errors, else 0                                   */
/*                                                                     */
/***********************************************************************/
int NiRtAdd(Ni *ni)
{
  ui32 subnet, subbrc;
  int rc;

  /*-------------------------------------------------------------------*/
  /* Check if adding a point-to-point interface.                       */
  /*-------------------------------------------------------------------*/
  if (ni->flags & NIF_P2P)
  {
    /*-----------------------------------------------------------------*/
    /* If local address is defined, add host route.                    */
    /*-----------------------------------------------------------------*/
    if (ni->ip_addr)
    {
      rc = RtAdd(htonl(INADDR_LOOPBACK), 0xFFFFFFFF, ni->ip_addr,
                 &Net.Local, 0);
      if (rc) return -1;
    }

    /*-----------------------------------------------------------------*/
    /* Else, if available, borrow address from another NI.             */
    /*-----------------------------------------------------------------*/
    else
    {
      ui32 addr = NiBorrowAddr();

      /*---------------------------------------------------------------*/
      /* If address available, use it. Else return error.              */
      /*---------------------------------------------------------------*/
      if (addr)
      {
        ni->flags |= NIF_BORROWED;
        ni->ip_addr = addr;
        ni->ip_mask = 0xFFFFFFFF;
      }
      else
      {
        NetError(NULL, EINVAL);
        return -1;
      }
    }

    /*-----------------------------------------------------------------*/
    /* If remote address supplied, add host route to it.               */
    /*-----------------------------------------------------------------*/
    if (ni->remote_addr)
    {
      rc = RtAdd(ni->ip_addr, 0xFFFFFFFF, ni->remote_addr, ni, 0);
      if (rc) goto man_err;
    }

    /*-----------------------------------------------------------------*/
    /* Else ensure default route option is requested.                  */
    /*-----------------------------------------------------------------*/
    else if ((ni->flags & NIF_DEF_GW) == FALSE)
    {
      NetError(NULL, EINVAL);
      goto man_err;
    }

    /*-----------------------------------------------------------------*/
    /* If requested, add default route to remote address.              */
    /*-----------------------------------------------------------------*/
    if (ni->flags & NIF_DEF_GW)
    {
      rc = RtAdd(ni->remote_addr, 0, htonl(INADDR_ANY), ni, RT_GATEWAY);
      if (rc) goto man_err;
    }
  }

  /*-------------------------------------------------------------------*/
  /* Else adding a broadcast interface.                                */
  /*-------------------------------------------------------------------*/
  else
  {
    /*-----------------------------------------------------------------*/
    /* Error if no address supplied.                                   */
    /*-----------------------------------------------------------------*/
    if (ni->ip_addr == 0)
    {
      NetError(NULL, EINVAL);
      return -1;
    }

    /*-----------------------------------------------------------------*/
    /* Add host route.                                                 */
    /*-----------------------------------------------------------------*/
    rc = RtAdd(htonl(INADDR_LOOPBACK), 0xFFFFFFFF, ni->ip_addr,
               &Net.Local, 0);
    if (rc) return -1;

    /*-----------------------------------------------------------------*/
    /* Add network route.                                              */
    /*-----------------------------------------------------------------*/
    subnet = ni->ip_addr & ni->ip_mask;
    rc = RtAdd(ni->ip_addr, ni->ip_mask, subnet, ni, 0);
    if (rc)
      goto man_err;

    /*-----------------------------------------------------------------*/
    /* Add subnet broadcast address.                                   */
    /*-----------------------------------------------------------------*/
    subbrc = ni->ip_addr | ~ni->ip_mask;
    rc = RtAdd(ni->ip_addr, 0xFFFFFFFF, subbrc, ni, RT_BRDCST);
    if (rc)
      goto man_err;
  }

  /*-------------------------------------------------------------------*/
  /* Set "up" flag and, if installed, call event callback function.    */
  /*-------------------------------------------------------------------*/
  ni->flags |= NIF_UP;
  if (ni->report)
    ni->report(ni, NIE_UP);
  return 0;

man_err:
  NiRtDel(ni);
  return -1;
}

/***********************************************************************/
/* Global Function Definitions                                         */
/***********************************************************************/

/***********************************************************************/
/*    tcpAddNi: Add a network interface                                */
/*                                                                     */
/*       Input: ni = pointer to network interface structure            */
/*                                                                     */
/*     Returns: -1 if errors, else 0                                   */
/*                                                                     */
/***********************************************************************/
int tcpAddNi(Ni *ni)
{
  int rc;
  Ni *np;

  /*-------------------------------------------------------------------*/
  /* Verify protocol has been initialized.                             */
  /*-------------------------------------------------------------------*/
  if (!Net.Initialized)
  {
    NetError(NULL, ENETDOWN);
    return -1;
  }

  /*-------------------------------------------------------------------*/
  /* Ensure all manditory functions are provided.                      */
  /*-------------------------------------------------------------------*/