Linux Network Programming

Linux Network Programming-general Linux technology-Linux technology and application information. For more information, see the following section. /**
* A sample server
*/
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Define PORT 8888
# Define BACKLOG 2

Void process_conn_server (int sock );

Int main (int argc, char ** argv)
{
Int sSock, cSock;
Struct sockaddr_in server_addr;
Struct sockaddr_in client_addr;
Int err;
Pid_t pid;
SSock = socket (AF_INET, SOCK_STREAM, 0); // create a TCP socket
If (-1 = sSock)
{
Printf ("Create socket error ");
Return-1;
}
Bzero (& server_addr, sizeof (server_addr); // initialize the address space
Server_addr.sin_family = AF_INET;
Server_addr.sin_addr.s_addr = htonl (INADDR_ANY );
Server_addr.sin_port = htons (PORT );
Err = bind (sSock, (struct sockaddr *) & server_addr, sizeof (server_addr ));
If (err <0)
{
Printf ("bind error ");
Return-1;
}
Printf ("Bind program is right, it return % d \ n", err );
Err = listen (sSock, BACKLOG );
If (err <0)
{
Printf ("listen error ");
Return-1;
}
Printf ("Listen program is right, it return % d \ n", err );


For (;;)
{
// Int addrlen = sizeof (struct sockaddr );
Socklen_t addrlen = sizeof (struct sockaddr );
CSock = accept (sSock, (struct sockaddr *) & client_addr, & addrlen );
Perror ("The state is :");
Pid = fork ();
If (pid <0)
{
Printf ("can't create new pid ");
Return-1;
}
If (pid = 0)
{
Close (sSock );
Process_conn_server (cSock );
Exit (0 );
}
Else
Close (cSock );
}
// Return 0;
}
Void process_conn_server (int sock)
{
Ssize_t size = 0;
Char buffer [1024];
Char sendbuffer [25] = "Welcome to this server \ n ";
Write (sock, sendbuffer, 25 );
For (;;)
{
Size = read (sock, buffer, 1024); // when the byte bit 0 is read, that is, when the sender stops sending, it will return
If (size = 0)
Return;
// Sprintf (buffer, "% d bytes altogether \ n", (int) size );
Write (sock, buffer, strlen (buffer) + 1 );
Write (STDOUT_FILENO, buffer, strlen (buffer) + 1 );
}
}


/*
* Client. c
* A sample client for server
*/
# Include
// # Include
# Include
# Include
// # Include
// # Include
# Include
# Include
# Include

# Define PORT 8888
Void process_conn_client (int s );

Int main (int argc, char * argv [])
{
Int s;
If (argc! = 2)
{
Printf ("client \ N ");
Return-1;
}
Struct sockaddr_in server_addr;
S = socket (AF_INET, SOCK_STREAM, 0 );
If (s <0)
{
Printf ("failed to creating socket ");
Return-1;
}
Bzero (& server_addr, sizeof (server_addr ));
Server_addr.sin_family = AF_INET;
Server_addr.sin_port = htons (PORT );
Inet_ton (AF_INET, argv [1], & server_addr.sin_addr );
Int cnum = connect (s, (struct sockaddr *) & server_addr, sizeof (struct sockaddr); // if the call succeeds, 0 is returned; otherwise,-1 is returned.
If (cnum <0)
{
Printf ("can't find the servers \ n ");
Return 0;
}
Process_conn_client (s );
Exit (0 );
}

Void process_conn_client (int s)
{

Ssize_t size = 0;
Char buffer [1024];
Char recvbuffer [25];
Read (s, recvbuffer, 25 );
Write (STDOUT_FILENO, recvbuffer, strlen (recvbuffer) + 1 );
For (;;)
{
// Buffer [1024] = {''};
Size = read (0, buffer, 1024); // read the standard input to the buffer. Here, An Initialization is required.
If (size> 0)
Write (s, buffer, strlen (buffer) + 1 );
// Printf (buffer );
Write (STDOUT_FILENO, buffer, strlen (buffer) + 1 );
}
}


The server and client code are as shown above. When the two are connected, the client is disconnected and should have been broken up four times, but I only caught three packets with wireshark, solve it for everyone!