Linux Sockets (1)

The properties of a socket are determined by three properties: domain, type, protocol.

1. Domain

Af_unix UNIX Domain protocol (file system sockets)

Af_inet arpa Internet Protocol (Unix network sockets)

... Omitted

2. Type

1) Flow socket: Sock_stream

2) Datagram Socket: Sock_dgram

3. Agreement

It is generally determined by the socket type and socket field, and usually does not need to be selected. Setting this parameter to 0 means that the default protocol is used.

Socket address.

1) Af_unix

struct Sockaddr_un {

sa_family_t sun_family; /* Af_unix */

Char sun_path[]; /* Pathname */

};

2) Af_inet

struct SOCKADDR_IN {

short int sin_family; /* Af_inet */

unsigned short int sin_port; /* Port number */

struct IN_ADDR sin_addr; /* Internet Address */

}; The structure is defined in the header file Netinet/in.h

The IP address structure in_addr is defined as:

struct IN_ADDR {

unsigned long int s_addr;

};

1. Naming sockets

#include <sys/socket.h>

int bind (int socket, const struct SOCKADDR *address, size_t Address_len);

2. Create a socket queue

#include <sys/socket.h>

int listen (int socket, int backlog);

3. Accept the connection

#include <sys/socket.h>

int accept (int socket, struct sockaddr *address, size_t *address_len);

4. Request a connection

#include <sys/socket.h>

int connect (int socket, const struct SOCKADDR *address, size_t Address_len);

5. Close the socket

Close ();

Linux Sockets (1)