DistanceVectorAlgorithm.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:  Thangarasu.K                                                       *
* ---------------------------------------------------------------------------------*/
#include "main.h"
#include "Routing.h"
#include "List.h"
#include "../IP/IP.h"
/**
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
This function runs the distance vector routing algorithm for optimized routing of packets from 
source to destination. The optimization is done per a particular metric, i.e the shortest distance.
This algorithm runs inside a single Autonomous System
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
int fn_NetSim_RIP_DistanceVectorAlgorithm(struct stru_NetSim_Network *NETWORK,NetSim_EVENTDETAILS *pstruEventDetails)
{
    NETSIM_ID nDeviceId,i;
    RIP_ROUTING_DATABASE *pstru_Router_RIP_TempTable=NULL;
    RIP_ROUTING_DATABASE *pstru_Router_RIP_TempTraverse=NULL,*pstru_Router_RIP_InsertTable=NULL;
    // NetSim packet To store the RIP packet
    NetSim_PACKET *pstruControlPacket = NULL;
    RIP_ENTRY *pstru_Router_RIP_RIPEntry=NULL;
    // RIP PACKET to store RIP packet data  
    RIP_PACKET *pstruPacketRIP = NULL;  
    pstruControlPacket=pstruEventDetails->pPacket;
    nDeviceId=pstruEventDetails->nDeviceId;
    pstruPacketRIP=pstruControlPacket->pstruAppData->Packet_AppProtocol;
    pstru_Router_RIP_RIPEntry=pstruPacketRIP->pstruRIPEntry;
    //Get the Routing database of the router
    pstru_Router_RIP_TempTable = ((DEVICE_ROUTER*)DEVICE_APPVAR(nDeviceId, APP_PROTOCOL_RIP))->pstruRoutingTables->pstruRIP_RoutingTable;
    fn_NetSim_Stack_GetDeviceId_asIP(pstruControlPacket->pstruNetworkData->szNextHopIp,&i);
    while(pstru_Router_RIP_RIPEntry)
    {
        pstru_Router_RIP_TempTraverse=pstru_Router_RIP_TempTable;
 
        while(pstru_Router_RIP_TempTraverse)
        {
            if(!IP_COMPARE(pstru_Router_RIP_TempTraverse->szAddress,pstru_Router_RIP_RIPEntry->szIPv4_address)&& !IP_COMPARE(pstru_Router_RIP_TempTraverse->szSubnetmask,pstru_Router_RIP_RIPEntry->szSubnet_Mask) )
            {
                if((pstru_Router_RIP_TempTraverse->nMetric  > pstru_Router_RIP_RIPEntry->nMetric+1))
                {
                    IP_FREE(pstru_Router_RIP_TempTraverse->szAddress);
                    IP_FREE(pstru_Router_RIP_TempTraverse->szRouter);
                    pstru_Router_RIP_TempTraverse->szAddress = IP_COPY(pstru_Router_RIP_RIPEntry->szIPv4_address);
                    pstru_Router_RIP_TempTraverse->szRouter = IP_COPY(pstruControlPacket->pstruNetworkData->szGatewayIP);
                    pstru_Router_RIP_TempTraverse->nMetric = pstru_Router_RIP_RIPEntry->nMetric + 1;
                    pstru_Router_RIP_TempTraverse->nInterface = i;
                    pstru_Router_RIP_TempTraverse->dTimer = pstruEventDetails->dEventTime;
                    {
                        iptable_add(IP_WRAPPER_GET(nDeviceId),
                                    pstru_Router_RIP_RIPEntry->szIPv4_address,
                                    pstru_Router_RIP_RIPEntry->szSubnet_Mask,
                                    0,
                                    pstruControlPacket->pstruNetworkData->szGatewayIP,
                                    1,
                                    &pstruControlPacket->pstruNetworkData->szNextHopIp,
                                    &i,
                                    pstru_Router_RIP_RIPEntry->nMetric + 1,
                                    "RIP");
                    }
                }
                break;
            }
            pstru_Router_RIP_TempTraverse = pstru_Router_RIP_TempTraverse->pstru_Router_NextEntry;
        }
        // If any new entry update that entry in the routing database
        if(!pstru_Router_RIP_TempTraverse)
        {
 
                pstru_Router_RIP_InsertTable=calloc(1,sizeof(RIP_ROUTING_DATABASE));
                pstru_Router_RIP_InsertTable->szAddress=pstru_Router_RIP_RIPEntry->szIPv4_address;
                pstru_Router_RIP_InsertTable->szSubnetmask = IP_COPY(pstru_Router_RIP_RIPEntry->szSubnet_Mask);
                pstru_Router_RIP_InsertTable->szRouter= IP_COPY(pstruControlPacket->pstruNetworkData->szGatewayIP);
                pstru_Router_RIP_InsertTable->nInterface=i;
                pstru_Router_RIP_InsertTable->nMetric=pstru_Router_RIP_RIPEntry->nMetric+1;
                pstru_Router_RIP_InsertTable->dTimer=pstruEventDetails->dEventTime;
                fn_NetSim_UpdateEntryinRoutingTable(NETWORK,pstruEventDetails,nDeviceId,pstru_Router_RIP_InsertTable->nInterface,0,pstru_Router_RIP_InsertTable->szAddress,pstru_Router_RIP_InsertTable->szRouter,pstru_Router_RIP_InsertTable->szSubnetmask,0,pstru_Router_RIP_InsertTable->nMetric,1);
                ((DEVICE_ROUTER*)(DEVICE_APPVAR(nDeviceId,APP_PROTOCOL_RIP)))->uniInteriorRouting.struRIP.nRIP_Update++;
 
                //Adding the entries in IP table
                {
                    iptable_add(IP_WRAPPER_GET(nDeviceId),
                                pstru_Router_RIP_RIPEntry->szIPv4_address,
                                pstru_Router_RIP_RIPEntry->szSubnet_Mask,
                                0,
                                pstruControlPacket->pstruNetworkData->szGatewayIP,
                                1,
                                &pstruControlPacket->pstruNetworkData->szNextHopIp,
                                &i,
                                pstru_Router_RIP_RIPEntry->nMetric + 1,
                                "RIP");
                }
                fnpFreeMemory(pstru_Router_RIP_InsertTable);
 
        }
        pstru_Router_RIP_RIPEntry=pstru_Router_RIP_RIPEntry->pstru_RIP_NextEntry;
    }
    if(pstruControlPacket)
    {
        fn_NetSim_Packet_FreePacket(pstruControlPacket);
        pstruEventDetails->pPacket=NULL;
    }
    return 0;
}