getnameinfo

Table of Contents >> Application Reference >> DNS Resolver

#include <trsocket.h>

int getnameinfo	(
	const struct sockaddr * addressPtr,
	int addressLength,
	char * hostname,
	int hostnameLength,
	char * serviceName,
	int serviceNameLength,
	int flags
	);

Function Description

Translates an address into it’s corresponding nodename (hostname). Similar to tfDnsGetHostByAddr(). Retrieving a service name or port number is not supported in our implementation of getnameinfo(), so serviceName must be set to NULL.

Non-blocking Mode

Like all of the other DNS functions, getnameinfo can be used in non-blocking mode by specifying TM_BLOCKING_OFF when tfDnsInit() is called. In non-blocking mode, getnameinfo may return TM_EWOULDBLOCK. This indicates that the operation is in progress. Continue to call getnameinfo() until a value other than TM_EWOULDBLOCK is returned, which indicates that the operation is complete. For example code using getnameinfo(), please see the examples/txdns.c file.

Parameters

• addressPtr

  Pointer to address to translate.

• addressLength

  Length of address structure.

• hostname

  Buffer to copy nodename into on completion.

• hostnameLength

  Size of hostname buffer.

• serviceName

  Not used.

• serviceNameLength

  Not used.

• flags

  NI_NUMERICHOST

Returns

• TM_ENOERROR

  Hostname info retrieved successfully.

• TM_ETIMEDOUT

  DNS request failed – requests to DNS server timed out.

• TM_EHOSTUNREACH

  No route to DNS server.

• TM_EWOULDBLOCK

  Indicates that an operation is currently in progress and has not yet completed. Only returned in non-blocking mode. (see above)

• EAI_NONAME

  NI_NUMERICHOST flag was set, but couldn’t convert binary address into string.

• EAI_FAMILY

  Unrecognized or unsupported address family.

• EAI_MEMORY

  Memory allocation failure

• EAI_FAIL

  Non-recoverable error occurred.

• EAI_NONAME

  No entry found for this address.

• TM_DNS_EFORMAT

  Error from DNS server: Format error. The name server was unable to interpret the query.

• TM_DNS_ESERVER

  Error from DNS server: Server failure. The name server was unable to process this query due to a problem with the name server.

• TM_DNS_ENAME_ERROR

  Error from DNS server: Name error. Meaningful only for responses from an authoritative name server, this code signifies that the domain name referenced in the query does not exist.

• TM_DNS_ENOT_IMPLEM

  Error from DNS server: Not implemented. The name server does not support the requested kind of query.

• TM_DNS_EREFUSED

  Error from DNS server: Refused. The name server refuses to perform the specified operation for policy reasons. For example, a name server may not wish to provide the information to the particular requester, or a name server may not wish to perform a particular operation (e.g., zone transfer) for particular data.

• TM_DNS_EANSWER

  No answer received from name server (i.e., response packet received, but it did not contain the answer to our query).

• TM_EFILE

  Treck was unable to successfully allocate a socket for the DNS request. This could indicate Treck did not have the resources to allocate another socket. It could also be due to Treck hitting the limit of sockets set by TM_DNS_MAX_SOCKETS_ALLOWED or the tfDnsSetOption() option: TM_DNS_OPTION_MAX_SOCKETS_ALLOWED.

Table of Contents >> Application Reference >> DNS Resolver