socket_if - retrieve scope_id for interface name and vice versa

NAME SYNTAX DESCRIPTION INTERFACE_NAME VERSUS SCOPE_ID BACKGROUND SOCKET FILES USAGE SEE ALSO

NAME

socket_if − retrieve scope_id for interface name and vice versa

SYNTAX

#include "socket_if.h"

uint32 socket_getifidx(const char *ifname);

const char *socket_getifname(uint32 scope_id);

DESCRIPTION

socket_getifidx returns the scope_id of an interface named as ifname typically ’’eth0’’.

socket_getifname retrieves from the operating system’s assigned scope_id the interface name ifname.

INTERFACE_NAME VERSUS SCOPE_ID

For IPv6 LLU addresses an additional ifname (interface name) has to be provided accompanying the IPv6 address: fe80::1%eth0. The operating systems rather uses scope_id as index for ifname.

For global IPv6 and ULA addresses ifname can be set to 0. Since IPv4 addresses on any interface are always unique, simply use 0 for all cases.

Qlib’s socket routines provide an easy API to setup TCP or UDP connections over IPv4 or IPv6 networks. Together with Qlib’s IP address parsing capabilities, a set of high-level socket routines allow a common IPv4/IPv6 handling.

SOCKET FILES

socket_bind.c

bind to or reuse the local IPv4/IPv6 address and port for a socket connection

socket_connect.c

attempts to setup a TCP or UDP client connection

socket_info.c

get local/remote IPv4/IPv6 address of socket

socket_recv.c

set up a receiving IPv4/IPv6 connection

socket_send.c

send UDP datagram over a IPv4 or IPv6 connection

socket_setup.c

listen to and accept an IPv4/IPv6 TCP socket connection

socket_tcp.c

create a non-blocking TCP stream socket

socket_udp.c

create a non-blocking UDP datagram socket

USAGE

Most of the above files include their IPv4 and IPv6 counterparts together with a combined usage requiring in addition a scope_id or simply 0. IPv4 addresses are usually converted upon reading to IPv4-mapped IPv6 addresses using Qlib’s IP address parsing functions. IPv4 and IPv6 socket calls - if required - need to be distinguished by the calling routines testing

ip6_isv4mapped(ip)

Otherwise, the unified IPv6/IPv4 versions will be used.