This document contains C code for creating a basic TCP server socket that listens for connections from clients and allows for bidirectional communication by reading from and writing to the client socket file descriptor. The code binds the server socket to port 4020 on IP address 10.180.5.196, accepts an incoming connection, and then enters a loop to continuously read messages from the client and write responses until the client sends the string "bye".

1. #include<stdio.h>
#include<unistd.h>
#include<sys/socket.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/un.h>
#include<string.h>
#include<termios.h>
#include<fcntl.h>
#include <stdlib.h>
intmain()
{
intsfd,result,client_sfd,ret;
socklen_tlen;
char buffer[256];
struct sockaddr_inaddr,client_addr;
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=inet_addr("10.180.5.196");
addr.sin_port=htons(4020);
sfd=socket(AF_INET,SOCK_STREAM,0);
if(sfd==-1)
{
printf("socketnotcreatedn");

2. exit(0);
}
result=bind(sfd,(structsockaddr*)&addr,sizeof(addr));
if(result==-1)
{
printf("bindingfailedn");
exit(0);
}
listen(sfd,5);
printf("waitingforclientn");
len=sizeof(client_addr);
client_sfd=accept(sfd,(struct sockaddr*) &client_addr,&len);
if(client_sfd==-1)
{
printf("connectionnotacceptedn");
exit(0);
}
while(strncmp(buffer,"bye",3)!=0){
bzero(buffer,255);
printf("client:");
read(client_sfd,buffer,255);
printf("%s",buffer);

3. printf("server:");
fgets(buffer,255,stdin);
write(client_sfd,buffer,255);
}
close(client_sfd);
}