hostname_cache.cc File Reference

Get hostname for an IP address. More...

#include "sql/hostname_cache.h"
#include "my_config.h"
#include "map_helpers.h"
#include "mutex_lock.h"
#include "my_psi_config.h"
#include "my_systime.h"
#include "mysql/components/services/bits/mysql_mutex_bits.h"
#include "mysql/components/services/bits/psi_mutex_bits.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/my_loglevel.h"
#include "thr_mutex.h"
#include <netdb.h>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <sys/socket.h>
#include <list>
#include <memory>
#include <new>
#include <string>
#include <unordered_map>
#include <utility>
#include "m_string.h"
#include "my_compiler.h"
#include "my_dbug.h"
#include "my_sys.h"
#include "mysql/psi/mysql_mutex.h"
#include "mysql/service_mysql_alloc.h"
#include "mysql/strings/m_ctype.h"
#include "mysqld_error.h"
#include "sql/log.h"
#include "sql/mysqld.h"
#include "sql/psi_memory_key.h"
#include "violite.h"
#include <arpa/inet.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 ()
list< unique_ptr< Host_entry > >::iterator	hostname_cache_begin ()
list< unique_ptr< Host_entry > >::iterator	hostname_cache_end ()
static Host_entry *	hostname_cache_search (const char *ip_string)
static void	add_hostname_impl (const char *ip_string, const char *hostname, bool validated, Host_errors *errors, ulonglong now)
static void	add_hostname (const char *ip_string, const char *hostname, bool validated, Host_errors *errors)
void	inc_host_errors (const char *ip_string, Host_errors *errors)
void	reset_host_connect_errors (const char *ip_string)
static bool	is_ip_loopback (const struct sockaddr *ip)
static bool	is_hostname_valid (const char *hostname)
int	ip_to_hostname (struct sockaddr_storage *ip_storage, const char *ip_string, char **hostname, uint *connect_errors)
	Resolve IP-address to host name. More...

Variables
static size_t	hostname_cache_max_size
static list< unique_ptr< Host_entry > > *	hostname_cache_lru
static malloc_unordered_map< string, list< unique_ptr< Host_entry > >::iterator > *	hostname_cache_by_ip
static mysql_mutex_t	hostname_cache_mutex
static bool	hostname_cache_mutex_inited = false

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.

Function Documentation

add_hostname()

static void add_hostname ( const char *  ip_string, const char *  hostname, bool  validated, Host_errors *  errors  )

static

add_hostname_impl()

static void add_hostname_impl ( const char *  ip_string, const char *  hostname, bool  validated, Host_errors *  errors, ulonglong  now  )

static

hostname_cache_begin()

list< unique_ptr< Host_entry > >::iterator hostname_cache_begin

(

)

hostname_cache_end()

list< unique_ptr< Host_entry > >::iterator hostname_cache_end

(

)

hostname_cache_free()

void hostname_cache_free

(

)

hostname_cache_init()

bool hostname_cache_init

(

uint

size

)

hostname_cache_lock()

void hostname_cache_lock

(

)

hostname_cache_refresh()

void hostname_cache_refresh

(

void

)

hostname_cache_resize()

void hostname_cache_resize

(

uint

size

)

hostname_cache_search()

static Host_entry * hostname_cache_search ( const char *  ip_string )

inlinestatic

hostname_cache_size()

uint hostname_cache_size

(

)

hostname_cache_unlock()

void hostname_cache_unlock

(

)

inc_host_errors()

void inc_host_errors	(	const char *	ip_string,
		Host_errors *	errors
	)

ip_to_hostname()

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	Hostname if IP-address is valid.
[out]	connect_errors	Represents number of connection errors.

Returns

Error status

Return values

0	Success
RC_BLOCKED_HOST	The host is blocked.
RC_LONG_HOSTNAME	The hostname is longer than HOSTNAME_LENGTH.

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.

is_hostname_valid()

static bool is_hostname_valid ( const char *  hostname )

inlinestatic

is_ip_loopback()

static bool is_ip_loopback ( const struct sockaddr *  ip )

inlinestatic

reset_host_connect_errors()

void reset_host_connect_errors

(

const char *

ip_string

)

Variable Documentation

hostname_cache_by_ip

malloc_unordered_map<string, list<unique_ptr<Host_entry> >::iterator>* hostname_cache_by_ip

static

hostname_cache_lru

list<unique_ptr<Host_entry> >* hostname_cache_lru

static

hostname_cache_max_size

size_t hostname_cache_max_size

static

hostname_cache_mutex

mysql_mutex_t hostname_cache_mutex

static

hostname_cache_mutex_inited

bool hostname_cache_mutex_inited = false

static