hostname.cc File Reference

Get hostname for an IP address. More...

#include "my_global.h"
#include "sql_priv.h"
#include "hostname.h"
#include "hash_filo.h"
#include <m_ctype.h>
#include "log.h"
#include "violite.h"
#include <sys/utsname.h>

Functions
void	hostname_cache_refresh ()
uint	hostname_cache_size ()
void	hostname_cache_resize (uint size)
bool	hostname_cache_init (uint size)
void	hostname_cache_free ()
void	hostname_cache_lock ()
void	hostname_cache_unlock ()
Host_entry *	hostname_cache_first ()
void	inc_host_errors (const char *ip_string, Host_errors *errors)
void	reset_host_connect_errors (const char *ip_string)
int	ip_to_hostname (struct sockaddr_storage *ip_storage, const char *ip_string, char **hostname, uint *connect_errors)

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Detailed Description

Get hostname for an IP address.

Hostnames are checked with reverse name lookup and checked that they doesn't resemble an IP address.

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Function Documentation

int ip_to_hostname	(	struct sockaddr_storage *	ip_storage,
		const char *	ip_string,
		char **	hostname,
		uint *	connect_errors
	)

Resolve IP-address to host name.

This function does the following things:

• resolves IP-address;
• employs Forward Confirmed Reverse DNS technique to validate IP-address;
• returns host name if IP-address is validated;
• set value to out-variable connect_errors -- this variable represents the number of connection errors from the specified IP-address.
• update the host_cache statistics

NOTE: connect_errors are counted (are supported) only for the clients where IP-address can be resolved and FCrDNS check is passed.

Parameters:

[in]	ip_storage	IP address (sockaddr). Must be set.
[in]	ip_string	IP address (string). Must be set.
[out]	hostname
[out]	connect_errors

Returns:

Error status

Return values:

0	Success
RC_BLOCKED_HOST	The host is blocked.

The function does not set/report MySQL server error in case of failure. It's caller's responsibility to handle failures of this function properly.