DNS sock API

Sock DNS client. More...

Detailed Description

Sock DNS client.

Files
file	dns.h
	DNS sock definitions.

Data Structures
struct	sock_dns_hdr_t
	DNS internal structure. More...

Functions
int	sock_dns_query (const char *domain_name, void *addr_out, int family)
	Get IP address for DNS name. More...

Variables
sock_udp_ep_t	sock_dns_server
	global DNS server endpoint

DNS defines
#define	DNS_TYPE_A   (1)
#define	DNS_TYPE_AAAA   (28)
#define	DNS_CLASS_IN   (1)
#define	SOCK_DNS_PORT   (53)
#define	SOCK_DNS_RETRIES   (2)
#define	SOCK_DNS_BUF_LEN   (128) /* we're in embedded context. */
#define	SOCK_DNS_MAX_NAME_LEN   (SOCK_DNS_BUF_LEN - sizeof(sock_dns_hdr_t) - 4)

Function Documentation

sock_dns_query()

int sock_dns_query	(	const char *	domain_name,
		void *	addr_out,
		int	family
	)

Get IP address for DNS name.

This function will synchronously try to resolve a DNS A or AAAA record by contacting the DNS server specified in the global variable sock_dns_server.

By supplying AF_INET, AF_INET6 or AF_UNSPEC in family requesting of A records (IPv4), AAAA records (IPv6) or both can be selected.

This function will return the first DNS record it receives. IF both A and AAAA are requested, AAAA will be preferred.

Note

addr_out needs to provide space for any possible result! (4byte when family==AF_INET, 16byte otherwise)

Parameters

[in]	domain_name	DNS name to resolve into address
[out]	addr_out	buffer to write result into
[in]	family	Either AF_INET, AF_INET6 or AF_UNSPEC

Returns

the size of the resolved address on success

< 0 otherwise