1th Network Programming Basics (3)-Basic socket communication

Server Common Model

(1) Initialize the monitor socket

Initialize socket

= socket (af_inet,socket_stream,ipproto_tcp); // create a socket as a listening port // socket type is stream socket // the network protocol used is the TCP protocol // Socket Family value is af_inet

Bind socket

== inet_addr ("127.0.0.1"= Htnos (9000); bind (s), ( LPSOCKETADDR)&addr,sizeof(addr)); // Socket Family value is af_inet // server address is 127.0.0.1 // the server uses a port of 9000

Start listening.

Listen (s,somaxconn); // Maximum number of connections system set maximum value

(2) Establishing a connection

Detecting socket Status

The function Select detects the corresponding socket state to determine whether a new connection needs to be established.

00; Fd_zero (&Readset); Fd_set (S,&readset); int Select (fd_setsize,&readset,null,null,&timeout); if (ret>0&&fd_isset (s,&// New connection    }

Create a new connection

Establish a new connection if the client has a new connection request fed

sockaddr_in addr; int sizeof  = Accept (S, (sockaddr*) &addr, (socklen_t*) &len); if (temp = = Invalid_socket) {// connection failed }

(3) Send and receive data

Detecting read-in data

00; Fd_zero (&Readset); Fd_set (S,&reader); int Select (fd_setsize,&readset,null,null,&timeout); if (ret>0&&fd_isset (s,&readset)) {// with new data }

Receive data

Char buf[1024x768]; int  = recv (s,buf,1024x768,0);

Detect sending Data

00; Fd_zero (&Wtiteset); Fd_set (S,&writeset); int Select (fd_setsize,&writeset,null,&timeout); if (ret>0&&fd_isset (s,&writeset)) {// can send data }

Send data

Char buf[1024x768]; int  = Send (S,buf,1024x768,0);

(4) Close the connection

Closesocket (s);

Client Common model

(1) Initialize socket

Create socket

= socket (af_inet,socket_stream,ipproto_tcp); // create a socket as a listening port // socket type is stream socket // the network protocol used is the TCP protocol // Socket Family value is af_inet

The types of sockets that the client and server side choose are consistent.

Binding port

The client's IP address and port number do not need to be fixed and can be assigned automatically by the system.

== = htons (0); Bind (S, (LPSOCKADDR)&addr,sizeof(addr)); // Socket Family value is af_inet // the client IP address and port are specified by the system

(2) Establishing a connection

When sending a connection request, you need to specify the port number and IP address of the server.

serveraddr.sin_family=af_inet; Serveraddr.sin_port=htons (9000); ServerAddr.sin_addr.s_addr=inet_addr ("127.0.0.1"); Connect (s, (Sockadd* ) &serveraddr,sizeof(serveraddr)); // Server Socket Family value is af_inet // Server port number is 9000 // Server IP address is 127.0.0.1

(3) Send and receive data

Same as Server

(4) Close the connection

Same as Server

1th Network Programming Basics (3)-Basic socket communication