Experiment with socket for point-to-point communication under Linux (server to client)

The server listens to two ports, which are then connected by the client, and no end has a send thread and accept thread dedicated to sending and receiving

Service-side process: Create a socket, bind port (to populate the network address structure first), listen for port,accept connections, and then transfer data

Client process: Create sockets, populate server-side network addresses, connect server-side ports, and transfer data

Service-side code

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


#define BUFLEN 1000
#define SEND_PORT 4000
#define Recv_port 4001
#define LISTEN_NUM 10


Set an connection, SOCKFD are the FD of sockets, CONFD is the FD of one connetction
void Set_conn (int *sockfd, int *confd,int port)
{
struct sockaddr_in s_addr, c_addr;
Socklen_t Len;
/* Build socket*/
if ((*SOCKFD = socket (af_inet, sock_stream, 0)) = = = 1)
{
Perror ("socket");
Exit (errno);
}


Fill the Address
memset (&s_addr,0,sizeof (S_ADDR));
s_addr.sin_family = af_inet;
S_addr.sin_port = htons (port);
S_ADDR.SIN_ADDR.S_ADDR = Inaddr_any;


Set the port as a reuseable port
int opt = 1;
SetSockOpt (*sockfd,sol_socket, so_reuseaddr, &opt, sizeof (opt));


Bind
if (bind (*SOCKFD, struct sockaddr*) &s_addr,sizeof (struct sockaddr)) = =-1)
{
Perror ("bind");
Exit (errno);
}


Listen
if (listen (*sockfd,listen_num) = =-1)
{
Perror ("Listen");
Exit (errno);
}


Accept
len = sizeof (struct sockaddr);
if (*CONFD = Accept (*SOCKFD, (struct sockaddr*) &c_addr, &len)) = =-1)
{
Perror ("accept");
Exit (errno);
}
}

Send Thread
void* th_send (void* Arg)
{
int SOCKFD, CONFD;
Char Buf[buflen];
Set_conn (&sockfd,&confd,send_port);
while (1)
{
Fgets (Buf,buflen,stdin);
if (!strcmp (buf, "exit"))
{
printf ("exiting\n");
Close (SOCKFD);
Close (CONFD);
return 0;
}
if (Send (Confd,buf,strlen (BUF), 0) = =-1)
{
Perror ("message sent Failed");
Exit (errno);
}
}
}

Receive thread
void* th_recv (void* Arg)
{
int SOCKFD, CONFD;
Char Buf[buflen];
Set_conn (&sockfd,&confd,recv_port);
while (1)
{
memset (Buf,0,buflen);
Switch (recv (confd,buf,buflen,0))
{
Case-1:///error occurred
Perror ("Failed to accept message");
Exit (errno);
Case 0:///peer have performed an orderly shutdown.
printf ("Client exited, chat terminated");
Return
Default://Receive succssed
printf ("client:%s", buf);
}
}
}


int main ()
{
pthread_t Tid_send,tid_recv;

Pthread_create (&tid_send,null,th_send,null);///Send Thread
Pthread_create (&tid_recv,null,th_recv,null);///Receive Thread

Pthread_join (Tid_send,null);
Pthread_join (Tid_recv,null);
return 0;
}

Client code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>


#define BUFLEN 10000
#define Send_port 4001
#define RECV_PORT 4000


int get_conn (int port)
{
int sockfd;
struct sockaddr_in s_addr;
Socklen_t Len;


/* Build socket*/
if ((SOCKFD = socket (af_inet, sock_stream, 0)) = = = 1)
{
Perror ("socket");
Exit (errno);
}


/* Set the server port */
memset (&s_addr,0,sizeof (S_ADDR));
s_addr.sin_family = af_inet;
S_addr.sin_port = htons (port);
S_ADDR.SIN_ADDR.S_ADDR = inet_addr ("127.0.0.1");


/* Connect to Server */
if (Connect (sockfd, struct sockaddr*) &s_addr,sizeof (struct sockaddr)) = =-1)
{
Perror ("Connect");
Exit (errno);
}
return SOCKFD;
}


void* th_send (void* Arg)
{


Char Buf[buflen];
int CONFD;
int ret;
CONFD = Get_conn (Send_port);
while (1)
{
Fgets (Buf,buflen,stdin);
if (!strcmp (buf, "exit"))
{
Close (CONFD);
printf ("exiting\n");
Return
}
if (Send (Confd,buf,strlen (BUF), 0) = =-1)
{
printf ("Return%d\n", ret);
Perror ("message sent Failed");
Exit (errno);
}
}
}


void* th_recv (void* Arg)
{
Char Buf[buflen];
int CONFD;
CONFD = Get_conn (Recv_port);
while (1)
{
memset (Buf,0,buflen);
Switch (recv (confd,buf,buflen,0))
{
Case-1:///error occurred
Perror ("Failed to accept message");
Exit (errno);
Case 0:///peer have performed an orderly shutdown.
printf ("Server exited, chat terminated");
Return
Default://Receive succssed
printf ("server:%s", buf);
}
}
}


int main ()
{
pthread_t Tid_send;
pthread_t Tid_recv;

Pthread_create (&tid_send,null,th_send,null);
Pthread_create (&tid_recv,null,th_recv,null);

Pthread_join (Tid_send,null);
Pthread_join (Tid_recv,null);
return 0;
}

Experiment with socket for point-to-point communication under Linux (server to client)