PacketProcessing.c

/************************************************************************************
 * Copyright (C) 2023                                                               *
 * 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:    Shashi Kant Suman                                                       *
 *                                                                                  *
 * ---------------------------------------------------------------------------------*/
#include "main.h"
#include "DSR.h"
#include "List.h"
/**
This function is called in the Network Out Event for routing of the packet.<br/>
 
Whenever a packet is to be routed to a destination and the device route cache doesnt have
a route to the target, the Packet is added to the Send buffer and a Route Discovery is 
iitiated.<br/>
 
If the Device route cache has a route to the target, then the packet is added to the Maintanence
Buffer and the count of packets originated is incremented.
 
*/
int fn_NetSim_DSR_GeneralPacketProcessing(NetSim_EVENTDETAILS* pstruEventDetails)
{
    NETSIM_IPAddress nextHop;
    NETSIM_ID nInterface;
    DSR_ROUTE_CACHE* cache=NULL;
    DSR_DEVICE_VAR* pstruDevVar = DSR_DEV_VAR(pstruEventDetails->nDeviceId);
    pstruEventDetails->pPacket->pstruNetworkData->szGatewayIP = IP_COPY(dsr_get_curr_ip());
    if(DSR_CHECK_ROUTE_FOUND(pstruEventDetails->pPacket->pstruNetworkData->szDestIP,
        pstruDevVar,&nextHop,pstruEventDetails->dEventTime,&cache))
    {
        //Route found
        DSR_ADD_SRC_ROUTE(pstruEventDetails->pPacket,cache);
        DSR_ADD_ACK_REQUEST(pstruEventDetails->pPacket);
        IP_FREE(pstruEventDetails->pPacket->pstruNetworkData->szNextHopIp);
        pstruEventDetails->pPacket->pstruNetworkData->szNextHopIp = IP_COPY(nextHop);
        pstruEventDetails->pPacket->pstruNetworkData->szGatewayIP = IP_COPY(dsr_get_curr_ip());
        pstruEventDetails->pPacket->nTransmitterId = pstruEventDetails->nDeviceId;
        pstruEventDetails->pPacket->nReceiverId = fn_NetSim_Stack_GetDeviceId_asIP(nextHop,&nInterface);
        DSR_ADD_TO_MAINT_BUFFER(pstruEventDetails->nDeviceId,pstruEventDetails->pPacket,pstruEventDetails->dEventTime);
        DSR_DEV_VAR(pstruEventDetails->nDeviceId)->dsrMetrics.packetTransmitted++;
        if(pstruEventDetails->pPacket->nSourceId == pstruEventDetails->nDeviceId)
            DSR_DEV_VAR(pstruEventDetails->nDeviceId)->dsrMetrics.packetOrginated++;
        if(DSR_DEV_VAR(pstruEventDetails->nDeviceId)->AckType == LINK_LAYER_ACK)
            pstruEventDetails->pPacket->ReceiveAckNotification = fn_NetSim_DSR_LinkLayerAck;
    }
    else
    {
        //Add packet to send buffer
        if(DSR_ADD_TO_SEND_BUFFER(&pstruDevVar->pstruSendBuffer,
            pstruEventDetails->pPacket,
            pstruEventDetails->dEventTime))
        {
            //Initiate Route discovery process
            NetSim_PACKET* packet = DSR_INIT_RREQ(pstruEventDetails->pPacket->pstruNetworkData->szDestIP,
                &pstruDevVar->pstruRREQTable,
                pstruEventDetails->nDeviceId,
                pstruEventDetails->dEventTime);
            pstruEventDetails->pPacket = packet;
            pstruEventDetails->dPacketSize = packet->pstruNetworkData->dPacketSize;
            pstruEventDetails->nApplicationId = 0;
            pstruEventDetails->nPacketId = 0;
        }
        else
        {
            //RREQ already sent
            pstruEventDetails->pPacket = NULL;//Don't transmit the packet
        }
    }
    return 1;
}