// This code is written by Souvik Ghosh
// Client Program

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

#define BUFLEN 512
#define PORT 8888

void die(char *s)
{
    perror(s);
    exit(1);
}

void *send_msg(void *arg)
{
    struct sockaddr_in si_other;
    int s, slen=sizeof(si_other);
    

    if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        die("socket");
    }

    memset((char *) &si_other, 0, sizeof(si_other));
    si_other.sin_family = AF_INET;
    si_other.sin_port = htons(PORT);
     
    if (inet_aton("127.0.0.1",&si_other.sin_addr) == 0) 
    {
        fprintf(stderr,"inet_aton() failed\n");
        exit(1);
    }
    
    while(1)
    { 
    
        char message[BUFLEN];
        fflush(stdin);
 
        fgets(message, BUFLEN, stdin);
         
        //send the message
        if (sendto(s, message, strlen(message) , 0 , (struct sockaddr *) &si_other, slen)==-1)
        {
            die("sendto()");
        }
        if(strncmp(message,"bye",3)==0)
        exit(0);
    }
}

void *recv_msg(void *arg)
{
    struct sockaddr_in si_me, si_other;
    int s, i, slen = sizeof(si_other) , recv_len;
    
     
    if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        die("socket");
    }
     
    memset((char *) &si_me, 0, sizeof(si_me));
     
    si_me.sin_family = AF_INET;
    si_me.sin_port = htons(PORT);
    si_me.sin_addr.s_addr = inet_addr("127.0.0.2");
     
    if( bind(s , (struct sockaddr*)&si_me, sizeof(si_me) ) == -1)
    {
        die("bind");
    }
     
    while(1)
    {
        char buf[BUFLEN];
        fflush(stdout);
       
        //try to receive some data, this is a blocking call
        if ((recv_len = recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen)) == -1)
        {
            die("recvfrom()");
        }
         
        //print details of the client/peer and the data received
        printf("Received packet from %s: %d\n",inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
        printf("Server: %s\n",buf);
        if(strncmp(buf,"bye",3)==0)
        exit(0);
    }
}

int main(void)
{
    pthread_t thread1, thread2;

    if(pthread_create(&thread1, NULL, send_msg, NULL)) 
    {
        fprintf(stderr, "Error creating thread\n");
        return 1;
    }

    if(pthread_create(&thread2, NULL, recv_msg, NULL)) 
    {
        fprintf(stderr, "Error creating thread\n");
        return 1;
    }

    pthread_join(thread1, NULL);
    pthread_join(thread2, NULL);

    return 0;
}

// This code is written by Souvik Ghosh
// Server program

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

#define BUFLEN 512
#define PORT 8888

void die(char *s)
{
    perror(s);
    exit(1);
}

void *send_msg(void *arg)
{
    struct sockaddr_in si_other;
    int s, slen=sizeof(si_other);
   
    

    if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        die("socket");
    }

    memset((char *) &si_other, 0, sizeof(si_other));
    si_other.sin_family = AF_INET;
    si_other.sin_port = htons(PORT);
     
    if (inet_aton("127.0.0.2",&si_other.sin_addr) == 0) 
    {
        fprintf(stderr, "inet_aton() failed\n");
        exit(1);
    }

    while(1)
    {
        char message[BUFLEN];
        fflush(stdin);
        
        fgets(message, BUFLEN, stdin);
         
        //send the message
        if (sendto(s, message, strlen(message) , 0 , (struct sockaddr *) &si_other, slen)==-1)
        {
            die("sendto()");
        }
        if(strncmp(message,"bye",3)==0)
        exit(0);
    }
}

void *recv_msg(void *arg)
{
    struct sockaddr_in si_me, si_other;
    int s, i, slen = sizeof(si_other) , recv_len;
    
     
    if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        die("socket");
    }
     
    memset((char *) &si_me, 0, sizeof(si_me));
     
    si_me.sin_family = AF_INET;
    si_me.sin_port = htons(PORT);
    si_me.sin_addr.s_addr = inet_addr("127.0.0.1");
     
    if( bind(s , (struct sockaddr*)&si_me, sizeof(si_me) ) == -1)
    {
        die("bind");
    }
     
    while(1)
    {
        char buf[BUFLEN];
        fflush(stdout);
         
        //try to receive some data, this is a blocking call
        if ((recv_len = recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen)) == -1)
        {
            die("recvfrom()");
        }
         
        //print details of the client/peer and the data received
        printf("Received packet from %s: %d\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
        printf("Client: %s\n", buf);
         if(strncmp(buf,"bye",3)==0){
         exit(0);
         }
    }
}

int main(void)
{
    pthread_t thread1, thread2;

    if(pthread_create(&thread1, NULL, send_msg, NULL)) 
    {
        fprintf(stderr, "Error creating thread\n");
        return 1;
    }

    if(pthread_create(&thread2, NULL, recv_msg, NULL)) 
    {
        fprintf(stderr, "Error creating thread\n");
        return 1;
    }

    pthread_join(thread1, NULL);
    pthread_join(thread2, NULL);

    return 0;
    
}