sub_server_2.c

#include <stdio.h>
#include <string.h>
#include <sys/socket.h> //socket
#include <arpa/inet.h> //inet_addr
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

int send_msg_to_main_server(char msg[])
{

    int socket_desc;
        struct sockaddr_in server_addr;
        char server_message[2000], client_message[2000];
        
        //Cleaning the Buffers
        
        memset(server_message,'\0',sizeof(server_message));
        memset(client_message,'\0',sizeof(client_message));
        
        //Creating Socket
        
        socket_desc = socket(AF_INET, SOCK_STREAM, 0);
        
        if(socket_desc < 0)
        {
                printf("Could Not Create Socket. Error!!!!!\n");
                return -1;
        }
        
        printf("Socket Created\n");
        
        //Specifying the IP and Port of the server to connect
        
        server_addr.sin_family = AF_INET;
        server_addr.sin_port = htons(2001);
        server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
        
        //Now connecting to the server accept() using connect() from client side
        
        if(connect(socket_desc, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0)
        {
                printf("Connection Failed. Error!!!!!");
                return -1;
        }
        
        printf("Connected\n");
        
        //Send the message to my information to Main Server
        
        strcpy(server_message,msg);
        printf("%s",server_message);

        if(send(socket_desc, server_message, strlen(server_message),0) < 0)
        {
                printf("Send Failed. Error!!!!\n");
                return -1;
        }
        
        memset(server_message,'\0',sizeof(server_message));
        memset(client_message,'\0',sizeof(client_message));
        
        //Closing the Socket
        
        close(socket_desc);
        
        return 0;
}

struct client_info
{
    int socket;
    int port;
    char ip[10];
    struct client_info* loc;
};

void *client_thread_func (void* c_info)
{
    printf("starting client_thread_func\n");
    
    char server_message[2000], client_message[2000],port_buffer[7];
    struct client_info *info=(struct client_info*) c_info;
    int client_sock=info->socket;
    printf("\nSocket: %i",client_sock);
    printf("\nPort: %i",info->port);
    printf("\nIP: %s",info->ip);
    printf("\nmalloc: %s ",info->loc);
    
    char test_type[]="Enter your test type:\nGeometry\nAlgebra\nIQ\n";
    
    //Cleaning the Buffers

    memset(server_message,'\0',sizeof(server_message));
    memset(client_message,'\0',sizeof(client_message));
    
    strcpy(server_message,test_type);
    if (send(client_sock, server_message, strlen(server_message),0)<0)
    {
        printf("client_thread_func Send Failed. Error!!!!!\n");
        return 0;
    }
    
    //Receive the message from the client

        if (recv(client_sock, client_message, sizeof(client_message),0) < 0)
        {
                printf("client_thread_func Receive Failed. Error!!!!!\n");
                return 0;
        }


        printf("client_thread_func Client Sock: %i\n",client_sock);
        printf("client_thread_func Client Message: %s\n",client_message);
        
        memset(server_message,'\0',sizeof(server_message));
        memset(port_buffer,'\0',sizeof(port_buffer));
        if(strcmp(client_message,"Geometry")==0 || strcmp(client_message,"Algebra")==0 || strcmp(client_message,"IQ")==0)
        {
            sprintf(port_buffer, "%d", info->port);
            strcpy(server_message,info->ip);
            strcat(server_message,",");
            strcat(server_message,port_buffer);
            strcat(server_message,",Math,");
            strcat(server_message,client_message);
            strcat(server_message,",20");
        }
        else
            strcpy(server_message, "Invalid Input!!!");
        

        //Send the message back to client
        if (send(client_sock, server_message, strlen(server_message),0)<0)
        {
                printf("client_thread_func Send Failed. Error!!!!!\n");
                return 0;
        }
        
        if(send_msg_to_main_server(server_message)==-1)
            return -1;
    
    close(client_sock);
    free(info->loc);
    pthread_exit(NULL); 
}

int Set_connection_for_clients(char my_ip[], char my_port[])
{   
    int port=atoi(my_port);
    
    
    int socket_desc, client_sock, client_size; 
        struct sockaddr_in server_addr, client_addr;
        pthread_t thread;
        
        //Creating Socket
        
        socket_desc = socket(AF_INET, SOCK_STREAM, 0);
        
        if(socket_desc < 0)
        {
                printf("Could Not Create Socket. Error!!!!!\n");
                return -1;
        }
        
        printf("Socket Created\n");
        
        //Binding IP and Port to socket
        
        server_addr.sin_family = AF_INET;
        server_addr.sin_port = htons(port);
        server_addr.sin_addr.s_addr = inet_addr(my_ip);
        
        if(bind(socket_desc, (struct sockaddr*)&server_addr, sizeof(server_addr))<0)
        {
                printf("Bind Failed. Error!!!!!\n");
                return -1;
        }        
        
        printf("Bind Done\n");
        
        //Put the socket into Listening State
        
        if(listen(socket_desc, 1) < 0)
        {
                printf("Listening Failed. Error!!!!!\n");
                return -1;
        }
        
        printf("Listening for Incoming Connections.....\n");
        
        
        while(1)
        {
            //Accept the incoming Connections

            client_size = sizeof(client_addr);
            client_sock = accept(socket_desc, (struct sockaddr*)&client_addr, &client_size);

            if (client_sock < 0)
            {
                    printf("Accept Failed. Error!!!!!!\n");
                    return -1;
            }
            else
            {
                struct client_info *info;
                info=malloc(sizeof(struct client_info));
                strcpy(info->ip,inet_ntoa(client_addr.sin_addr));
                info->port=ntohs(client_addr.sin_port);
                info->socket=client_sock;
                info->loc=info;
                
                int ret = pthread_create(&thread, NULL, client_thread_func, (void *)info);
                if (ret!=0)
                {
                    printf("Error In Creating Thread\n");
                }
            }


            //printf("Client Connected with IP: %s and Port No: %i\n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));
        }
              
        //Closing the Socket


        close(socket_desc);
        pthread_exit(NULL); //Terminates the parent thread    
    
    
    return 0;
}


int main(int argc, char** argv) {

    char msg[100];
    char my_test_name[]="Math";
    char my_ip[]="127.0.0.1";
    char my_port[]="2020";
    
    memset(msg,'\0',sizeof(msg));

    strcpy(msg,my_test_name);
    strcat(msg,",");
    strcat(msg,my_ip);
    strcat(msg,",");
    strcat(msg,my_port);
        
    if(send_msg_to_main_server(msg)==-1)
        return -1;
    
    Set_connection_for_clients(my_ip,my_port);

    
    return (EXIT_SUCCESS);
}