root/vtcross/trunk/src/policy_engines/PolicyEngine.cpp @ 201

/* Virginia Tech Cognitive Radio Open Source Systems
 * Virginia Tech, 2009
 *
 * LICENSE INFORMATION GOES HERE
 */

/* DESCRIPTION OF FILE.
 */


#include <cstdlib>
#include <cstring>
#include <stdint.h>

#include "vtcross/common.h"
#include "vtcross/components.h"
#include "vtcross/containers.h"
#include "vtcross/debug.h"
#include "vtcross/error.h"
#include "vtcross/socketcomm.h"


PolicyEngine::PolicyEngine()
{
    LOG("Creating Policy Engine.\n");
    SML_present = false;
    LoadPolicies();
}


PolicyEngine::~PolicyEngine()
{
}


PolicyEngine::PolicyEngine(const char* serverName, const char* serverPort, \
        const bool SML)
{
    LOG("Creating Policy Engine.\n");

    SML_present = SML;
    
    ConnectToRemoteComponent(serverName, serverPort);

    LoadPolicies();
}


void
PolicyEngine::SendComponentType()
{
    SendMessage(commandSocketFD, "response_engine_policy");
    LOG("Policy Engine responded to GetRemoteComponentType query.\n");
}


void
PolicyEngine::ConnectToRemoteComponent(const char* serverName, \
        const char* serverPort)
{
    commandSocketFD = ClientSocket(serverName, serverPort);

    if(SML_present) {
        RegisterServices();
        LOG("Policy Engine connected to SML at %s.\n", serverName);
    }
    else {
        RegisterComponent();
        LOG("Policy Engine connected to shell at %s.\n", serverName);
    }
}


void 
PolicyEngine::WaitForSignal()
{
    char buffer[256];

    while(true) {
        memset(buffer, 0, 256);
       
        ReadMessage(commandSocketFD, buffer);

        // TODO this is ugly... is there a better way? Doesn't strcmp compare the
        // whole string?  We only need to compare until we find a single different
        // byte...
        //
        // If we send integer op codes rather than strings, this process will be
        // MUCH faster since instead of donig string compares we can simply
        // switch on the integer value...
        if(strcmp(buffer, "validate_parameters") == 0) {
            ValidateParameters();
        }
        else if(strcmp(buffer, "query_component_type") == 0) {
            SendComponentType();
        }
        else if(strcmp(buffer, "connect_sml") == 0) {
            /* This command implies that we are disconnecting from the shell and
             * connecting to a SML component. */
            char serverName[256];
            char serverPort[256];
            // TODO is this going to end up being too slow?
            memset(serverName, 0, 256);
            memset(serverPort, 0, 256);

            ReadMessage(commandSocketFD, serverName);
            ReadMessage(commandSocketFD, serverPort);

            /* Only continue if we are currently connected to a shell. */
            if(!SML_present) {
                DeregisterComponent();

                shutdown(commandSocketFD, 2);
                close(commandSocketFD);

                SML_present = true;

                ConnectToRemoteComponent(serverName, serverPort);
            }
        }
        else if(strcmp(buffer, "disconnect_sml") == 0) {
            /* This command implies that we are disconnecting from the SML and
             * connecting to a shell component. */
            char serverName[256];
            char serverPort[256];
            // TODO is this going to end up being too slow?
            memset(serverName, 0, 256);
            memset(serverPort, 0, 256);

            ReadMessage(commandSocketFD, serverName);
            ReadMessage(commandSocketFD, serverPort);

            /* We only want to do this if we are actually connected to an SML
             * currently. */
            if(SML_present) {
                DeregisterServices();

                shutdown(commandSocketFD, 2);
                close(commandSocketFD);

                SML_present = false;

                ConnectToRemoteComponent(serverName, serverPort);
            }
        }
        else if(strcmp(buffer, "reload_engine_configs") == 0) {
            ReloadPolicies();
        }
        else if(strcmp(buffer, "reset_engine_policy") == 0) {
            Reset();
        }
        else if(strcmp(buffer, "shutdown_engine_policy") == 0) {
            Shutdown();
        }
    }
}


void 
PolicyEngine::Shutdown()
{
    if(SML_present)
        DeregisterServices();
    else
        DeregisterComponent();

    // TODO should something else be happening here?
}


void
PolicyEngine::Reset()
{
    LOG("Resetting Policy Engine.\n");
    SML_present = false;
    commandSocketFD = -1;
    LoadPolicies();
}


void
PolicyEngine::RegisterComponent()
{
    SendMessage(commandSocketFD, "register_engine_policy");
    LOG("Policy Engine:: Registration message sent to shell.\n");
}


void 
PolicyEngine::DeregisterComponent()
{
    SendMessage(commandSocketFD, "deregister_engine_policy");
    LOG("Policy Engine:: Deregistration message sent to shell.\n");

    shutdown(commandSocketFD, 2);
    close(commandSocketFD);
    LOG("Policy Engine:: Shell socket closed.\n");
}


void 
PolicyEngine::RegisterServices()
{
    LOG("Policy Engine:: Registering services.\n");
    SendMessage(commandSocketFD, "register_service_pe_geo");
    SendMessage(commandSocketFD, "register_service_pe_time");
    SendMessage(commandSocketFD, "register_service_pe_spectrum");
    SendMessage(commandSocketFD, "register_service_pe_spacial");
}


void 
PolicyEngine::DeregisterServices()
{
    LOG("Policy Engine:: Deregistering services.\n");
    SendMessage(commandSocketFD, "deregister_service_pe_geo");
    SendMessage(commandSocketFD, "deregister_service_pe_time");
    SendMessage(commandSocketFD, "deregister_service_pe_spectrum");
    SendMessage(commandSocketFD, "deregister_service_pe_spacial");

    shutdown(commandSocketFD, 2);
    close(commandSocketFD);
    LOG("Policy Engine:: SML socket closed.\n");
}


void 
PolicyEngine::LoadPolicies()
{
    LOG("PolicyEngine:: Loading policies.\n");
}


void 
PolicyEngine::ReloadPolicies()
{
    LOG("PolicyEngine:: Reloading policies.\n");
}


void 
PolicyEngine::SendPEDecision(struct Parameter pList[], \
        struct Radio_Info *radio_info, int32_t decision_array[])
{
    char var[50];
 
    for (size_t i = 0; i < radio_info->numParameters; i++) {
        sprintf(var, "%i", decision_array[i]);
        SendMessage(commandSocketFD, var);
    }
}


void 
PolicyEngine::ValidateParameters()
{
    LOG("Policy Engine:: Preparing to receive parameters for validation....\n");

    int32_t decision_array[10];
    struct Parameter pList[10];
    struct Radio_Info radio_info;

    if(GetRequest(commandSocketFD, pList, &radio_info)) {
        LOG("Policy Engine:: Validating Transmission Parameters.\n");
        for (size_t i = 0; i < radio_info.numParameters; i++)
            decision_array[i] = 1;

        LOG("Policy Engine:: Sending Policy decision to Server.\n");
        SendPEDecision(pList, &radio_info, decision_array);

        LOG("Policy Engine:: Policies Validated.\n");
    }
    else
        ERROR(1, "Call to GetRequest in ValidateParameters failed.\n");

}