Linux Network Programming [1] socket address

• Three Linux socket addresses

• Common socket address of sockaddr

typedef unsigned short sa_family_t;struct sockaddr {        sa_family_t     sa_family;    /* address family, AF_xxx       */        char            sa_data[14];    /* 14 bytes of protocol address */}

• Socket address of sockaddr_in Internet

/* Structure describing an internet socket address. */struct sockaddr_in {_ sockaddr_common (SIN _); in_port_t sin_port;/* port number. */struct in_addr sin_addr;/* Internet address. * // * pad to size of 'struct sockadd '. */unsigned char sin_zero [sizeof (struct sockaddr)-_ sockaddr_common_size-sizeof (in_port_t)-sizeof (struct in_addr)]; /* The character array sin_zero [8] exists to ensure that the size of the struct sockaddr_in is equal to the size of the struct sockaddr */}; struct in_addr {unit32_t s_addr; /* Internet address */};

• Socket address of the sockaddr_un UNIX System

Struct sockaddr_un {sa_family_t sun_family;/* pf_unix or af_unix */Char sun_path [unix_path_max];/* path */};

• Address Translation in Linux socket

In general, the X86 architecture PC uses the small-end mode to store data, while in the socket, the large-end mode is required, so the relevant conversion is required. Common conversion functions include:

• Socket universal conversion functions

Ntohl converts 32-bit network data into host data

Ntohs converts 16-bit network data into host data

Htonl converts 32-bit host data into network data

Htons converts 16-bit network data into network data

• Inet Conversion Function

Inet_ntoa converts the IP address of the network byte to a decimal vertex address.

Inet_aton converts the dotted-decimal address to the IP address of the network byte.

Inet_network converts the dot-decimal to 32-bit data of host bytes.

• Summary

Generally, the sockaddr_in structure is used when network programming is used to fill in the value. When passed in as a function parameter, it is converted to the sockaddr structure, which is a string of 16 characters.Long.