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

#include <stdio.h> 
#include <string.h> 
#include <sys/types.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <pthread.h> 
#define MAX_SIZE 50 
char msg[MAX_SIZE]; 

void *recvmg(void *my_sock) 
{ 
 int sock = *((int *)my_sock); 
 int len; 
 // client thread always ready to receive message 
 while((len = recv(sock,msg,MAX_SIZE,0)) > 0) { 
 msg[len] = '\0'; 
 fputs(msg,stdout); 
 } 
} 

int main(int argc,char *argv[]) 
{ 
 pthread_t recvt; 
 int sock_desc; 
 struct sockaddr_in serv_addr; 
 char client_name[MAX_SIZE]; 
 char recvmsg[MAX_SIZE]; 
 strcpy(client_name, argv[1]); 
 
 if((sock_desc = socket(AF_INET, SOCK_STREAM, 0)) < 0) 
 printf("Failed creating socket\n"); 
 bzero((char *) &serv_addr, sizeof (serv_addr)); 
 serv_addr.sin_family = AF_INET; 
 serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); 
 serv_addr.sin_port = htons(3000); 
 if (connect(sock_desc, (struct sockaddr *) &serv_addr, sizeof (serv_addr)) < 0) { 
 printf("Failed to connect to server\n"); 
 return -1; 
 } 
 
 //creating a client thread which is always waiting for a message 
 pthread_create(&recvt,NULL,(void *)recvmg,&sock_desc); 
 
 char data[MAX_SIZE]; 
 char sendMSG[MAX_SIZE]; 
 while(1){ 
 fgets(data,MAX_SIZE,stdin); 
 strcpy(sendMSG,client_name); 
 strcat(sendMSG,": "); 
 strcat(sendMSG,data); 
 //send the message/reply 
 write(sock_desc,&sendMSG,sizeof(sendMSG)); 
 } 
 exit(0); 
 close(sock_desc); 
 return 0; 
} 

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

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

pthread_mutex_t mutex; 
int clients[20]; 
int n=0; 

void sendtoall(char *msg,int curr){ 
 int i; 
 pthread_mutex_lock(&mutex); 
 for(i = 0; i < n; i++) { 
 if(clients[i] != curr) { 
 if(send(clients[i],msg,strlen(msg),0) < 0) { 
 printf("sending failure \n"); 
 continue; 
 } 
 } 
 } 
 pthread_mutex_unlock(&mutex); 
} 

void *recvmg(void *client_sock){ 
 int sock = *((int *)client_sock); 
 char msg[500]; 
 int len; 
 while((len = recv(sock,msg,500,0)) > 0) { 
 msg[len] = '\0'; 
 fputs(msg,stdout); 
 sendtoall(msg,sock); 
 } 
} 

int main(){ 
 struct sockaddr_in ServerIp; 
 pthread_t recvt; 
 int sock=0 , Client_sock=0; 
 ServerIp.sin_family = AF_INET; 
 ServerIp.sin_port = htons(3000); 
 ServerIp.sin_addr.s_addr = inet_addr("127.0.0.1"); 
 sock = socket(AF_INET,SOCK_STREAM,0 ); 
 if( bind( sock, (struct sockaddr *)&ServerIp, sizeof(ServerIp)) == -1 ) 
 printf("cannot bind, error!! \n"); 
 else 
 printf("Server Started...\n"); 
 if( listen( sock ,20 ) == -1 ) 
 printf("listening failed!! \n"); 
 while(1){ 
 if( (Client_sock = accept(sock, (struct sockaddr *)NULL,NULL)) < 0 ){ 
 printf("accept failed!!\n"); 
 }else{ 
 printf("new client joins the chat!!\n"); 
 } 
 pthread_mutex_lock(&mutex); 
 clients[n]= Client_sock; 
 n++; 
 // creating a thread for each client 
 pthread_create(&recvt,NULL,(void *)recvmg,&Client_sock); 
 pthread_mutex_unlock(&mutex); 
 } 
 return 0; 
}