tcp_ni.c

用于嵌入式系统的TCP/IP协议栈

  if ((ni->poll == NULL) || (ni->transmit == NULL) ||
      (!(ni->flags & NIF_P2P) && (ni->broadcast == NULL)))
  {
    NetError(NULL, EINVAL);
    return -1;
  }

  /*-------------------------------------------------------------------*/
  /* Ensure improper flags are not set.                                */
  /*-------------------------------------------------------------------*/
  if (ni->flags & (NIF_UP | NIF_BORROWED))
  {
    NetError(NULL, EINVAL);
    return -1;
  }

  /*-------------------------------------------------------------------*/
  /* Acquire access to protocol internals.                             */
  /*-------------------------------------------------------------------*/
  semPend(Net.IntSem, WAIT_FOREVER);

  /*-------------------------------------------------------------------*/
  /* Clear statistics fields in network interface structure.           */
  /*-------------------------------------------------------------------*/
  ni->ipkts = ni->ierrs = ni->opkts = ni->oerrs = 0;

  /*-------------------------------------------------------------------*/
  /* Ensure interface is not already installed.                        */
  /*-------------------------------------------------------------------*/
  for (np = Net.Local.next; np; np = np->next)
    if (np == ni)
    {
      NetError(NULL, EINVAL);
      rc = -1;
      goto add_err;
    }

  /*-------------------------------------------------------------------*/
  /* Determine address assignment method and call appropriate routine. */
  /*-------------------------------------------------------------------*/
  if (ni->flags & NIF_USE_DHCP)
    rc = DhcpAdd(ni);
  else if (ni->flags & NIF_USE_RARP)
    rc = RarpAdd(ni);
  else
    rc = NiRtAdd(ni);

  /*-------------------------------------------------------------------*/
  /* If successful, add to linked list of network interfaces.          */
  /*-------------------------------------------------------------------*/
  if (rc == 0)
  {
    ni->next = Net.Local.next;
    Net.Local.next = ni;
  }

  /*-------------------------------------------------------------------*/
  /* Release access to protocol internals and return status.           */
  /*-------------------------------------------------------------------*/
add_err:
  semPost(Net.IntSem);
  return rc;
}

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

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

  /*-------------------------------------------------------------------*/
  /* Acquire access to protocol internals.                             */
  /*-------------------------------------------------------------------*/
  semPend(Net.IntSem, WAIT_FOREVER);

  /*-------------------------------------------------------------------*/
  /* Search linked list, starting at local interface.                  */
  /*-------------------------------------------------------------------*/
  for (np = &Net.Local;;)
  {
    /*-----------------------------------------------------------------*/
    /* Advance, remembering the previous interface.                    */
    /*-----------------------------------------------------------------*/
    prev = np;
    np = np->next;

    /*-----------------------------------------------------------------*/
    /* If interface found, remove from linked list and break.          */
    /*-----------------------------------------------------------------*/
    if (np == ni)
    {
      prev->next = ni->next;
      break;
    }

    /*-----------------------------------------------------------------*/
    /* If end reached, interface was not installed.                    */
    /*-----------------------------------------------------------------*/
    if (np == NULL)
    {
      NetError(NULL, EINVAL);
      semPost(Net.IntSem);
      return -1;
    }
  }

  /*-------------------------------------------------------------------*/
  /* Stop DHCP state machine if using DHCP.                            */
  /*-------------------------------------------------------------------*/
  if (ni->flags & NIF_USE_DHCP)
    DhcpDel(ni);

  /*-------------------------------------------------------------------*/
  /* Delete all routes associated with the interface.                  */
  /*-------------------------------------------------------------------*/
  NiRtDel(ni);

  /*-------------------------------------------------------------------*/
  /* Check if IP address has been assigned and is not been borrowed.   */
  /*-------------------------------------------------------------------*/
  if (ni->ip_addr && ((ni->flags & NIF_BORROWED) == FALSE))
  {
    /*-----------------------------------------------------------------*/
    /* See if another interface "owns" this address also.              */
    /*-----------------------------------------------------------------*/
    for (np = Net.Local.next; np; np = np->next)
    {
      if ((np->ip_addr == ni->ip_addr) && !(np->flags & NIF_BORROWED))
        break;
    }

    /*-----------------------------------------------------------------*/
    /* If this was only owner, must bring borrowers down.              */
    /*-----------------------------------------------------------------*/
    if (np == NULL)
    {
      for (np = Net.Local.next; np; np = np->next)
        if ((np->ip_addr == ni->ip_addr) && (np->flags & NIF_BORROWED))
          NiRtDel(np);
    }
  }

  /*-------------------------------------------------------------------*/
  /* Delete any queued buffers associated with the interface.          */
  /*-------------------------------------------------------------------*/
  NiBufFree(ni);

  /*-------------------------------------------------------------------*/
  /* Release access to protocol internals and return success.          */
  /*-------------------------------------------------------------------*/
  semPost(Net.IntSem);
  return 0;
}

/***********************************************************************/
/*   tcpStatNi: Read network interface status                          */
/*                                                                     */
/*       Input: ni = pointer to network interface structure            */
/*                                                                     */
/*     Returns: TRUE if interface is up, 0 if down, -1 if errors       */
/*                                                                     */
/***********************************************************************/
int tcpStatNi(const char *name)
{
  Ni *ni;

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

  /*-------------------------------------------------------------------*/
  /* Acquire access to protocol internals.                             */
  /*-------------------------------------------------------------------*/
  semPend(Net.IntSem, WAIT_FOREVER);

  /*-------------------------------------------------------------------*/
  /* Search through list of network interfaces.                        */
  /*-------------------------------------------------------------------*/
  for (ni = &Net.Local; ni; ni = ni->next)
  {
    /*-----------------------------------------------------------------*/
    /* Read state and break if named interface is found.               */
    /*-----------------------------------------------------------------*/
    if (!strcmp(name, ni->name))
      break;
  }

  /*-------------------------------------------------------------------*/
  /* Release access to protocol internals and return status.           */
  /*-------------------------------------------------------------------*/
  semPost(Net.IntSem);
  return (ni != NULL) && (ni->flags & NIF_UP);
}