root/vtcross/branches/bhilburn/src/policy_engines/default_policy_engine.c @ 120

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>

#include "cbr.h"

#define CR_PORT 30002

struct CE_Info {
    int numUtilities;
    int numParameters;
    int numObservables;
};

struct Parameter {
    /*string name;
    string units;*/
    char name[50];
    char units[50];
    float min;
    float max;
    float step;
    float value;
};      
        
// error handling
void error(char *msg)
{
    perror(msg);
    exit(0);
}

void ReadMessage(int socket,char * buffer) {
    int i,n;

    n = recv(socket,buffer,256,MSG_PEEK);
    for(i=0;i<256;i++){
            if(strcmp(&buffer[i],"\0") == 0) break;
    }
    n = recv(socket,buffer,i+1,0);
    if (n < 0) 
         error("ERROR reading from socket");
    //printf("ReadMessage:%s %d\n",buffer,n);
}

// setup client socket connection
int ClientSocket(int argc, char** argv)
{
    int sockfd;
    int portno;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    
    // server name
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    // port no.
    portno = atoi(argv[2]);
    // socket file descriptor
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    // initiate struct socketaddr_in
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(portno);
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    // cast sockaddr_in to sockaddr
    if (connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");

    return sockfd;
}

    
int SendMessage(int socketfd, char *message) 
{
    int n;
     
    strcat(message, "\0000");
    n = send(socketfd,message,(strlen(message)+1),0);
    if (n<0)
        error("Error sending to server\n");
    else if(n == 0)
        printf("Server closed the socket.\n");
   
    return n;
}

int GetParameter(int sockfd, struct Parameter pList[], struct CE_Info *ce_info)
{
    char buffer[256];
    int i;

    // numParameters
    bzero(buffer,256);
    ReadMessage(sockfd,buffer);
    ce_info->numParameters = atoi(buffer);
    printf("number of parameters: %d\n", ce_info->numParameters);
    
    for (i = 0; i < ce_info->numParameters; i++){
        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Name: %s\n", buffer);
        strcpy(pList[i].name, buffer);
    
        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Units: %s\n", buffer);
        strcpy(pList[i].units, buffer);

        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Min: %s\n", buffer);
        pList[i].min = atof(buffer);
    
        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Max: %s\n", buffer);
        pList[i].max = atof(buffer);
    
        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Step: %s\n", buffer);
        pList[i].step = atof(buffer);
    
        bzero(buffer,256);
        ReadMessage(sockfd,buffer);
        printf("Value: %s\n", buffer);
        pList[i].value = atof(buffer);
    
    }
    return 1;
}


int GetRequest(int sockfd, struct Parameter pList[], struct CE_Info *ce_info)
{
    char buffer[256];
   
    // Get control identifier
    // Possibly could implement some sort of authentication here
    bzero(buffer,256);
    ReadMessage(sockfd,buffer);

    if(strcmp(buffer,"val") != 0) {
            printf("Policy Engine:: Unexpected control data received.\n\n");
        return 0;
    }

    printf("Policy Engine:: Getting parameters.\n\n");
    // Get potenial transmission parameter values
    GetParameter(sockfd, pList, ce_info);

    return 1;
}

int ValidateTransmissionParameters(struct Parameter pList[], struct CE_Info *ce_info, int decision_array[])
{
    int i = 0;
    // Decision array holds parameter decision
    // 1 = OK
    // 0 = FAIL

    printf("Policy Engine:: Policies Validated.\n\n");
    for (i = 0; i < ce_info->numParameters; i++){
        decision_array[i] = 1;
    }

    return 1;
}


int RegisterPE(int sockfd)
{
    // Send register message to cognitive radio
    SendMessage(sockfd, "p_register");
    printf("Policy Engine:: Registration message sent.\n\n");
    return 1;
}

int SendCEDecision(int sockfd, struct Parameter pList[], struct CE_Info *ce_info, int decision_array[])
{
    // send results back to server
    char var[50];
    int i;
 
    // parameter
    for (i = 0; i < ce_info->numParameters; i++){
        sprintf(var, "%i", decision_array[i]);
        SendMessage(sockfd, var);
    }
    
    return 1;
}

int ParsePolicies() {

    printf("Policy Engine:: Policies parsed.\n\n");

    return 1;
}

// main client socket
int main(int argc, char *argv[])
{
    int decision_array[10];
    struct Parameter pList[10];
    struct CE_Info ce_info;
    int sockfd;
    int ret = 0;
    
    // setup client socket connection
    if (argc < 3) {
       fprintf(stderr,"usage: %s hostname port\n", argv[0]);
       exit(0);
    }
    
    // setup client socket connection with server
    sockfd = ClientSocket(argc, argv);

    // Parse initial Policies 
    printf("Policy Engine:: Parsing local policies.\n\n");
    ret = ParsePolicies();

    ret = RegisterPE(sockfd);

    while(1) {
        
        printf("Policy Engine:: Waiting for Policy Check Request.\n\n");
        ret = GetRequest(sockfd, pList, &ce_info);
       
        if(ret == 1) {
            printf("Policy Engine:: Validating Transmission Parameters.\n\n");
            ValidateTransmissionParameters(pList, &ce_info, decision_array);    
   
            printf("Policy Engine:: Sending Policy decision to Server.\n\n");
            SendCEDecision(sockfd, pList, &ce_info, decision_array);
        }
    }
    
    return 0;
}