Socket Programming in C, TCP over a network (2 systems)

tcpserver.c

 
#include"stdio.h"
#include"stdlib.h"
#include"sys/types.h"
#include"sys/socket.h"
#include"string.h"
#include"netinet/in.h"

#define PORT 4444
#define BUF_SIZE 2000

void main() {
 struct sockaddr_in addr, cl_addr;
 int sockfd, len, ret, newsockfd;
 char buffer[BUF_SIZE];
 
 sockfd = socket(AF_INET, SOCK_STREAM, 0);
 if (sockfd < 0) {
  printf("Error creating socket!\n");
  exit(1);
 }
 printf("Socket created...\n");
 
 memset(&addr, 0, sizeof(addr));
 addr.sin_family = AF_INET;
 addr.sin_addr.s_addr = INADDR_ANY;
 addr.sin_port = PORT;
 
 ret = bind(sockfd, (struct sockaddr *) &addr, sizeof(addr));
 if (ret < 0) {
  printf("Error binding!\n");
  exit(1);
 }
 printf("Binding done...\n");

 printf("Waiting for a connection...\n");
 listen(sockfd, 5);

 len = sizeof(cl_addr);
 newsockfd = accept(sockfd, (struct sockaddr *) &cl_addr, &len);
 if (newsockfd < 0) {
  printf("Error accepting connection!\n");
  exit(1);
 }
 printf("Connection accepted...\n"); 

 memset(buffer, 0, BUF_SIZE);
 ret = recv(newsockfd, buffer, BUF_SIZE, 0);
 if(ret < 0) {
  printf("Error receiving data!\n");  
  exit(1);
 }
 printf("Received data: %s\n", buffer); 

 ret = send(newsockfd, buffer, strlen(buffer), 0);  
 if (ret < 0) {  
  printf("Error sending data!\n");  
  exit(1);  
 }  
 printf("Sent data: %s\n", buffer);
 close(sockfd);
 close(newsockfd);
}

tcpclient.c

 
#include"stdio.h"  
#include"stdlib.h"  
#include"sys/types.h"  
#include"sys/socket.h"  
#include"string.h"  
#include"netinet/in.h"  
#include"netdb.h"
  
#define PORT 4444 
#define BUF_SIZE 2000 
  
int main(int argc, char**argv) {
 struct sockaddr_in addr, cl_addr;  
 int sockfd, ret;  
 char buffer[BUF_SIZE];  
 struct hostent * server;
 char * serverAddr;

 if (argc < 2) {
  printf("usage: client < ip address >\n");
  exit(1);  
 }

 serverAddr = argv[1];

 sockfd = socket(AF_INET, SOCK_STREAM, 0);  
 if (sockfd < 0) {  
  printf("Error creating socket!\n");  
  exit(1);  
 }  
 printf("Socket created...\n");   

 memset(&addr, 0, sizeof(addr));  
 addr.sin_family = AF_INET;  
 addr.sin_addr.s_addr = inet_addr(serverAddr);
 addr.sin_port = PORT;     

 ret = connect(sockfd, (struct sockaddr *) &addr, sizeof(addr));  
 if (ret < 0) {  
  printf("Error connecting to the server!\n");  
  exit(1);  
 }  
 printf("Connected to the server...\n");  

 memset(buffer, 0, BUF_SIZE);
 printf("Enter your message: ");
 scanf("%s", buffer);
 ret = send(sockfd, buffer, strlen(buffer), 0);  
 if (ret < 0) {  
  printf("Error sending data!\n");  
  exit(1);  
 }  
 printf("Sent data: %s\n", buffer);  

 memset(buffer, 0, BUF_SIZE);  
 ret = recv(sockfd, buffer, BUF_SIZE, 0);  
 if(ret < 0) {  
  printf("Error receiving data!\n");    
  exit(1);  
 }  
 printf("Received data: %s\n", buffer); 

 return 0;
}  

Output:

terminal 1
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ gcc tcpserver.c -o server
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ gcc tcpclient.c -o client
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ ./server
Socket created...
Binding done...
Waiting for a connection...
Connection accepted...
Received data: hi
Sent data: hi
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ p-laptop:~/coding/tcp_2sys$ gcc tcpclient.c -o client
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ ./server
Socket created...
Binding done...
Waiting for a connection...
Connection accepted...
Received data: hi
Sent data: hi

dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ 

terminal 2
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ ./client 
usage: client
dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$ ./client 192.168.0.4
Socket created...
Connected to the server...
Enter your message: hi
Sent data: hi
Received data: hi

dhanoopbhaskar@dhanoop-laptop:~/coding/tcp_2sys$