Static Hostname definitions

This enables functionality like /etc/hosts for dns_query() More...

Detailed Description

This enables functionality like /etc/hosts for dns_query()

This module allows to make static hostname - IP address mappings that will be taken into consideration when using dns_query() or a higher level API that makes use of dns_query().

To enable this, add the hosts module to your Makefile:

USEMODULE += hosts

Usage

To add a static hostname mapping to your code, just declare it with HOST_IPV4() or HOST_IPV6() anywhere in a .c file

#define IPV4_ADDR_EXAMPLE_COM IPV4_ADDR_INIT(192,168,42,23)
#define IPV6_ADDR_EXAMPLE_COM {{ 0xfd, 0x00, 0x00, 0x00, \
                                 0x00, 0x00, 0x00, 0x00, \
                                 0x00, 0x00, 0x00, 0x00, \
                                 0x00, 0x00, 0x42, 0x23 }}
 
HOST_IPV4(example.com, IPV4_ADDR_EXAMPLE_COM);
HOST_IPV6(example.com, IPV6_ADDR_EXAMPLE_COM);

The hostname should then be resolved by any tool or function that makes use of dns_query():

> ping example.com
12 bytes from fd::42:23: icmp_seq=0 ttl=64 time=1.202 ms
12 bytes from fd::42:23: icmp_seq=1 ttl=64 time=1.202 ms
12 bytes from fd::42:23: icmp_seq=2 ttl=64 time=1.202 ms
 
--- example.com PING statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 1.202/1.202/1.202 ms

Files
file	hosts.h
	Static mappings from hostnames to IP addresses.

Data Structures
struct	hostnames_v4_xfa_t
	A single IPv4 host in the list of hostnames. More...
struct	hostnames_v6_xfa_t
	A single IPv6 host in the list of hostnames. More...

Macros
#define	HOST_IPV4(host, ip)
	Define IPv4 host. More...
#define	HOST_IPV6(host, ip)
	Define IPv6 host. More...

Functions
int	hosts_query (const char *host_name, void *addr_out, int family)
	Get IP address for a host name. More...

Macro Definition Documentation

HOST_IPV4

#define HOST_IPV4	(		host,
			ip
	)

Value:

    XFA_USE_CONST(hostnames_v4_xfa_t, hostnames_v4_xfa); \
    static FLASH_ATTR const char _xfa_ ## host ## _hostname[] = #host; \
    XFA_CONST(hostnames_v4_xfa_t, hostnames_v4_xfa, 0) _xfa_ ## host ## _host = { \
        .name = _xfa_ ## host ## _hostname, \
        .addr = ip, \
    };

Define IPv4 host.

Note

This is not available from C++, but a trivial C++ file can easily hook up a extern "C" function implemented in C.

This macro is a helper for defining a hostname -> address mapping and adding it to the host names XFA (cross file array).

Example:

#include "hosts.h"
HOST_IPV4(localhost, IPV4_ADDR_LOOPBACK);

Definition at line 105 of file hosts.h.

HOST_IPV6

#define HOST_IPV6	(		host,
			ip
	)

Value:

    XFA_USE_CONST(hostnames_v6_xfa_t, hostnames_v6_xfa); \
    static FLASH_ATTR const char _xfa_ ## host ## _hostname[] = #host; \
    XFA_CONST(hostnames_v6_xfa_t, hostnames_v6_xfa, 0) _xfa_ ## host ## _host = { \
        .name = _xfa_ ## host ## _hostname, \
        .addr = ip, \
    };

Define IPv6 host.

Note

This is not available from C++, but a trivial C++ file can easily hook up a extern "C" function implemented in C.

This macro is a helper for defining a hostname -> address mapping and adding it to the host names XFA (cross file array).

Example:

#include "hosts.h"
HOST_IPV6(localhost, IPV6_ADDR_LOOPBACK);

Definition at line 129 of file hosts.h.

Function Documentation

hosts_query()

int hosts_query	(	const char *	host_name,
		void *	addr_out,
		int	family
	)

Get IP address for a host name.

Host Name <-> IP address mappings can be statically defined with the HOST_IPV6 macro.

Parameters

[in]	host_name	Host name to resolve into address
[out]	addr_out	Buffer to write result into, but be able to accommodate an address of the selected family
[in]	family	Either AF_INET (IPv4), AF_INET6 (IPv6) or AF_UNSPEC (either IPv4 or IPv6)

Returns

the size of the resolved address on success or an error code

Return values

-ENOENT

if no matching entry could be found