Network_Layer_Ack.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 adds the Acknowledge request option to the packet.
*/
int fn_NetSim_DSR_Add_Ack_request_Option(NetSim_PACKET* packet,
    NetSim_EVENTDETAILS* pstruEventDetails)
{
    DSR_OPTION_HEADER* option = (DSR_OPTION_HEADER*)packet->pstruNetworkData->Packet_RoutingProtocol;
    static unsigned int nIdentification=1; 
    if(DSR_DEV_VAR(pstruEventDetails->nDeviceId)->AckType == NETWORK_LAYER_ACK)
    {
        if(!option->ackRequestOption)
            option->ackRequestOption = (DSR_ACK_REQ_OPTION*)calloc(1,sizeof* option->ackRequestOption);
        option->ackRequestOption->nOptionType = optType_AckRequest;
        option->ackRequestOption->nIdentification = nIdentification++;
        packet->pstruNetworkData->dPacketSize+=DSR_ACK_REQUEST_LEN;
        packet->pstruNetworkData->dOverhead+=DSR_ACK_REQUEST_LEN;
    }
    else
    {
        if(option->ackRequestOption)
        {
            option->ackRequestOption = NULL;
            packet->pstruNetworkData->dPacketSize-=DSR_ACK_REQUEST_LEN;
            packet->pstruNetworkData->dOverhead-=DSR_ACK_REQUEST_LEN;
        }
    }
    return 1;
}
/**
If a packet has an acknowledge request option, this function generates the acknowledge
and transmits it.
*/
int fn_NetSim_DSR_Process_AckRequestOption(NetSim_PACKET* packet,NetSim_EVENTDETAILS* pstruEventDetails)
{
    DSR_OPTION_HEADER* option = (DSR_OPTION_HEADER*)packet->pstruNetworkData->Packet_RoutingProtocol;
    if(option->ackRequestOption)
    {
        NetSim_EVENTDETAILS pevent;
        DSR_ACK_REQ_OPTION* ackRequest = option->ackRequestOption;
        NetSim_PACKET* ppacket = fn_NetSim_DSR_GenerateCtrlPacket(pstruEventDetails->nDeviceId,
            packet->nTransmitterId,
            packet->nTransmitterId,
            pstruEventDetails->dEventTime,
            ctrlPacket_ACK);
        option = (DSR_OPTION_HEADER*)calloc(1,sizeof* option);
        DSR_ACK_OPTION* ack = (DSR_ACK_OPTION*)calloc(1,sizeof* ack);
        ppacket->pstruNetworkData->Packet_RoutingProtocol = option;
        option->options = ack;
        option->nNextHeader = NO_NEXT_HEADER;
        option->optType = optType_Ack;
        option->nPayloadLength = DSR_ACK_OPTION_LEN;
 
        ack->DestAddress = dsr_get_dev_ip(packet->nTransmitterId);
        ack->nIdentification = ackRequest->nIdentification;
        ack->nOptionDataLen = DSR_ACK_OPTION_LEN;
        ack->nOptionType = optType_Ack;
        ack->sourceAddress = dsr_get_curr_ip();
        ppacket->pstruNetworkData->dOverhead = DSR_ACK_OPTION_LEN+DSR_OPTION_HEADER_SIZE;
        ppacket->pstruNetworkData->dPacketSize = DSR_ACK_OPTION_LEN+DSR_OPTION_HEADER_SIZE;
        ppacket->pstruNetworkData->nTTL = 2;
        //Transmit ack
        memcpy(&pevent,pstruEventDetails,sizeof* pstruEventDetails);
        pevent.dPacketSize = DSR_ACK_OPTION_LEN+DSR_OPTION_HEADER_SIZE;
        pevent.nApplicationId = 0;
        pevent.nEventType = NETWORK_OUT_EVENT;
        pevent.nPacketId = 0;
        pevent.nProtocolId = fn_NetSim_Stack_GetNWProtocol(pevent.nDeviceId);
        pevent.nSegmentId = 0;
        pevent.nSubEventType = 0;
        pevent.pPacket = ppacket;
        fnpAddEvent(&pevent);
    }
    return 1;
}
/**
Whenever an acknowlegement is received, the DSR Maintenance Buffer is Emptied.
*/
int fn_NetSim_DSR_ProcessAckOption(NetSim_EVENTDETAILS* pstruEventDetails)
{
    NetSim_PACKET* packet = pstruEventDetails->pPacket;
    NETSIM_ID nSource = packet->nSourceId;
    DSR_EMPTY_MAINT_BUFFER(pstruEventDetails->nDeviceId,nSource);
    fn_NetSim_Packet_FreePacket(packet);
    pstruEventDetails->pPacket=NULL;
    return 1;
}