RequestTimeOut.c

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/************************************************************************************
 * Copyright (C) 2020     
 *
 * TETCOS, Bangalore. India                                                         *
 
 * Tetcos owns the intellectual property rights in the Product and its content.     *
 * The copying, redistribution, reselling or publication of any or all of the       *
 * Product or its content without express prior written consent of Tetcos is        *
 * prohibited. Ownership and / or any other right relating to the software and all  *
 * intellectual property rights therein shall remain at all times with Tetcos.      *
 
 * Author:   Basamma YB 
 * Date  :   
 ************************************************************************************/
 
#define _CRT_SECURE_NO_DEPRECATE
#include "main.h"
#include "ARP.h"
/**
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Function: ARP Request Timeout 
When we generate Arp Request, we will add the Timeout event with the present 
event time + ARP_RETRY_INTERVAL. At that time this function is called.
Do the following to generate Request
1. Check the destination entry present in the table and set nDestinationPresentFlag. 
2. if nDestinationPresentFlag =0 Check RetryCont<RetryLimit.
3. if true generate ARP request, reset pnArpRequestFlag, increament nArpRequestSentCount.
4. else drop the buffered packets and reset the RetryCount and RequestFlag.
3. if nDestinationPresentFlag set,drop temp packet and reset RetryCount and RequestFlag
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
int fn_NetSim_ARP_Request_Timeout(NetSim_EVENTDETAILS *pstruEventDetails, struct stru_NetSim_Network *NETWORK)
{
    NETSIM_ID nDeviceId;
    NETSIM_ID nInterfaceId;
    NETSIM_ID nDestinationId,i;
    NETSIM_IPAddress szDestIPadd;
    
    int nPktDropCount=0;
    int nDestinationPresentFlag = 0;
    
    NetSim_PACKET *pstruTemp_Data;      // store the packet from the event details  
    ARP_VARIABLES *pstruArpVariables;   //type casting Arp variables
    ARP_BUFFER *pstruPacketBuffer;      //type casting Arp buffer
    ARP_TABLE  *pstruTableHead, *pstruCurrentTable; //Type casting ARP table 
    
    pstruTemp_Data = pstruEventDetails->pPacket;    //Get the packet from the event     
    nDeviceId = pstruEventDetails->nDeviceId;       // Get the deviceID
    nInterfaceId = pstruEventDetails->nInterfaceId; // Get the  interfaceId 
    
    
    //Shashi kant
    szDestIPadd = IP_COPY(pstruTemp_Data->pstruNetworkData->szNextHopIp);
    // Get the source and destination IP address from the packet
    //szSrcIPadd = IP_COPY(pstruTemp_Data->pstruNetworkData->szSourceIP);
    //szDestIPadd = IP_COPY(pstruTemp_Data->pstruNetworkData->szDestIP);
    //szNextHopIp =  pstruTemp_Data->pstruNetworkData->szNextHopIp;
    //if(IP_COMPARE(szSrcIPadd,DEVICE_INTERFACE(nDeviceId,nInterfaceId)->szAddress) != 0)
    //{
    //  szSrcIPadd = IP_COPY(DEVICE_INTERFACE(nDeviceId,nInterfaceId)->szAddress);
    //}
    ///*if(szNextHopIp)
    //  szDestIPadd = szNextHopIp;*/
    //szSubnetMaskAdd = IP_COPY(DEVICE_INTERFACE(nDeviceId,nInterfaceId)->szSubnetMask);
    //// Call the IPV4 function to check Destination MAC in the same subnet/LAN
    //nCheckSubnet = IP_IS_IN_SAME_NETWORK(szSrcIPadd,szDestIPadd,szSubnetMaskAdd);
    //// Get the Arp variables from device ipVar
    pstruArpVariables = DEVICE_INTERFACE(nDeviceId,nInterfaceId)->ipVar;
    pstruTableHead = pstruArpVariables->pstruArpTable;
    //  switch(nCheckSubnet)
    //  {
    //  case 1: // Destination in the same LAN      
    //      nDestinationId = pstruEventDetails->pPacket->nDestinationId;
    //      //szDestIPadd = _strdup(pstruTemp_Data->pstruNetworkData->szDestIP);
    //      break;
    //  case 2:// Destination in the different LAN
    //      nDestinationId = 0;         // for the Default Gateway
    //      szDestIPadd = IP_COPY(DEVICE_INTERFACE(nDeviceId,nInterfaceId)->szDefaultGateWay);          
    //      break;
    //  default:            
    //      fnNetSimError("Invalid Data From IPV4 in Read ARP Table function");
    //      return 0;
    //      break;
    //  }//switch end
 
 
 
 
 
        // Check the destination entry in the table
        pstruCurrentTable = pstruTableHead;         
        while(pstruCurrentTable != 0) 
        {
            if(IP_COMPARE(pstruCurrentTable->szIPAddress,szDestIPadd)== 0)
            {
                nDestinationPresentFlag = 1; //Entry exist in the table
                break;
            }
            else
                pstruCurrentTable = pstruCurrentTable->pstruNextEntry;
        }       
        nDestinationId =  fn_NetSim_Stack_GetDeviceId_asIP(pstruEventDetails->pPacket->pstruNetworkData->szNextHopIp,&i);
    if(!nDestinationPresentFlag)
    {
        
        // If RetryCont<RetryLimit, generate ARP request, else drop the buffered packets    
        if(pstruArpVariables->pnArpRetryCount[nDestinationId] < pstruArpVariables->nArpRetryLimit)
        {   // Write to Log file    
            printf("\n%s\n","ARP---Reply not received with in the ARP_RETRY_INTERVAL, send request once again");            
            pstruArpVariables->pnArpRequestFlag[nDestinationId] = 0; // Reset the flag
            pstruEventDetails->nSubEventType = GENERATE_ARP_REQUEST;
            fnpAddEvent(pstruEventDetails);             
        }
        else 
        {   // Drop the buffered packets
            char ipstr[_NETSIM_IP_LEN];
            pstruPacketBuffer = pstruArpVariables->pstruPacketBuffer;
            IP_TO_STR(pstruPacketBuffer->pstruPacket->pstruNetworkData->szGatewayIP,ipstr);
            nPktDropCount = 0;
            fn_NetSim_Arp_Drop_Buffered_Packet(nDeviceId,nInterfaceId,szDestIPadd,&nPktDropCount);
            pstruPacketBuffer = pstruArpVariables->pstruPacketBuffer;
            // update the packet count in the buffer                
            pstruArpVariables->pstruArpMetrics->nPacketDropCount+= nPktDropCount;
            pstruArpVariables->pstruArpMetrics->nPacketsInBuffer-= nPktDropCount;
            // Reset the RetryCount and RequestFlag
            pstruArpVariables->pnArpRetryCount[nDestinationId] = 0;
            pstruArpVariables->pnArpRequestFlag[nDestinationId] = 0;
            
            // Write to Log file    
            printf("\n%s\n","ARP---Request reached the ARP_RETRY_LIMIT, drop the packet");
            printf("ARP---Packets Dropped at\tEventTime:%0.3lf\tSrcIP:%s\tDropCount:%d\n",pstruEventDetails->dEventTime,ipstr,nPktDropCount);
 
        }       
    }
    else
    {   // Reset the RetryCount and RequestFlag
        pstruArpVariables->pnArpRetryCount[nDestinationId] = 0;
        pstruArpVariables->pnArpRequestFlag[nDestinationId] = 0;
        // free the packet
        fn_NetSim_Packet_FreePacket(pstruTemp_Data);
        pstruEventDetails->pPacket = NULL;
    }
 
 
    //shashi kant
    /*IP_FREE(szSubnetMaskAdd);
    IP_FREE(szSrcIPadd);
    IP_FREE(szDestIPadd);   */
    return 0;   
}