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evdns_compat(3) Library Functions Manual evdns_compat(3)
NAME
evdns_compat - Potentially non-threadsafe versions of the functions in
dns.h: provided only for backwards compatibility.
SYNOPSIS
#include <event2/dns_compat.h>
#include <event2/event-config.h>
#include <event2/util.h>
Functions
struct evdns_server_port * evdns_add_server_port (evutil_socket_t
socket, int flags, evdns_request_callback_fn_type callback, void
*user_data)
As evdns_server_new_with_base.
int evdns_clear_nameservers_and_suspend (void)
Remove all configured nameservers, and suspend all pending
resolves.
int evdns_count_nameservers (void)
Get the number of configured nameservers.
struct evdns_base * evdns_get_global_base (void)
Return the global evdns_base created by event_init() and used by
the other deprecated functions.
int evdns_init (void)
Initialize the asynchronous DNS library.
int evdns_nameserver_add (unsigned long int address)
Add a nameserver.
int evdns_nameserver_ip_add (const char *ip_as_string)
Add a nameserver.
int evdns_resolv_conf_parse (int flags, const char *const filename)
Parse a resolv.conf file.
int evdns_resolve_ipv4 (const char *name, int flags,
evdns_callback_type callback, void *ptr)
Lookup an A record for a given name.
int evdns_resolve_ipv6 (const char *name, int flags,
evdns_callback_type callback, void *ptr)
Lookup an AAAA record for a given name.
int evdns_resolve_reverse (const struct in_addr *in, int flags,
evdns_callback_type callback, void *ptr)
Lookup a PTR record for a given IP address.
int evdns_resolve_reverse_ipv6 (const struct in6_addr *in, int flags,
evdns_callback_type callback, void *ptr)
Lookup a PTR record for a given IPv6 address.
int evdns_resume (void)
Resume normal operation and continue any suspended resolve
requests.
void evdns_search_add (const char *domain)
Add a domain to the list of search domains.
void evdns_search_clear (void)
Clear the list of search domains.
void evdns_search_ndots_set (const int ndots)
Set the 'ndots' parameter for searches.
int evdns_set_option (const char *option, const char *val, int flags)
Set the value of a configuration option.
void evdns_shutdown (int fail_requests)
Shut down the asynchronous DNS resolver and terminate all active
requests.
Detailed Description
Potentially non-threadsafe versions of the functions in dns.h: provided
only for backwards compatibility.
Function Documentation
struct evdns_server_port* evdns_add_server_port (evutil_socket_t socket,
int flags, evdns_request_callback_fn_type callback, void * user_data)
As evdns_server_new_with_base.
Deprecated
This function is deprecated because it does not allow the caller to
specify which even_base it uses. The recommended function is
evdns_add_server_port_with_base().
int evdns_clear_nameservers_and_suspend (void)
Remove all configured nameservers, and suspend all pending resolves.
Resolves will not necessarily be re-attempted until evdns_resume() is
called.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_clear_nameservers_and_suspend().
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_resume()
int evdns_count_nameservers (void)
Get the number of configured nameservers. This returns the number of
configured nameservers (not necessarily the number of running
nameservers). This is useful for double-checking whether our calls to
the various nameserver configuration functions have been successful.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_count_nameservers().
Returns:
the number of configured nameservers
See also:
evdns_nameserver_add()
struct evdns_base* evdns_get_global_base (void)
Return the global evdns_base created by event_init() and used by the
other deprecated functions.
Deprecated
This function is deprecated because use of the global evdns_base is
error-prone.
int evdns_init (void)
Initialize the asynchronous DNS library. This function initializes
support for non-blocking name resolution by calling
evdns_resolv_conf_parse() on UNIX and
evdns_config_windows_nameservers() on Windows.
Deprecated
This function is deprecated because it always uses the current
event base, and is easily confused by multiple calls to
event_init(), and so is not safe for multithreaded use.
Additionally, it allocates a global structure that only one thread
can use. The replacement is evdns_base_new().
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_shutdown()
int evdns_nameserver_add (unsigned long int address)
Add a nameserver. The address should be an IPv4 address in network byte
order. The type of address is chosen so that it matches in_addr.s_addr.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_nameserver_add().
Parameters:
address an IP address in network byte order
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_nameserver_ip_add()
int evdns_nameserver_ip_add (const char * ip_as_string)
Add a nameserver. This wraps the evdns_nameserver_add() function by
parsing a string as an IP address and adds it as a nameserver.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_nameserver_ip_add().
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_nameserver_add()
int evdns_resolv_conf_parse (int flags, const char *const filename)
Parse a resolv.conf file. The 'flags' parameter determines what
information is parsed from the resolv.conf file. See the man page for
resolv.conf for the format of this file.
The following directives are not parsed from the file: sortlist,
rotate, no-check-names, inet6, debug.
If this function encounters an error, the possible return values are: 1
= failed to open file, 2 = failed to stat file, 3 = file too large, 4 =
out of memory, 5 = short read from file, 6 = no nameservers listed in
the file
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_resolv_conf_parse().
Parameters:
flags any of
DNS_OPTION_NAMESERVERS|DNS_OPTION_SEARCH|DNS_OPTION_MISC|
DNS_OPTIONS_ALL
filename the path to the resolv.conf file
Returns:
0 if successful, or various positive error codes if an error
occurred (see above)
See also:
resolv.conf(3), evdns_config_windows_nameservers()
int evdns_resolve_ipv4 (const char * name, int flags, evdns_callback_type
callback, void * ptr)
Lookup an A record for a given name.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_resolve_ipv4().
Parameters:
name a DNS hostname
flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for
this query.
callback a callback function to invoke when the request is
completed
ptr an argument to pass to the callback function
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_resolve_ipv6(), evdns_resolve_reverse(),
evdns_resolve_reverse_ipv6()
int evdns_resolve_ipv6 (const char * name, int flags, evdns_callback_type
callback, void * ptr)
Lookup an AAAA record for a given name.
Parameters:
name a DNS hostname
flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for
this query.
callback a callback function to invoke when the request is
completed
ptr an argument to pass to the callback function
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_resolve_ipv4(), evdns_resolve_reverse(),
evdns_resolve_reverse_ipv6()
int evdns_resolve_reverse (const struct in_addr * in, int flags,
evdns_callback_type callback, void * ptr)
Lookup a PTR record for a given IP address.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_resolve_reverse().
Parameters:
in an IPv4 address
flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for
this query.
callback a callback function to invoke when the request is
completed
ptr an argument to pass to the callback function
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_resolve_reverse_ipv6()
int evdns_resolve_reverse_ipv6 (const struct in6_addr * in, int flags,
evdns_callback_type callback, void * ptr)
Lookup a PTR record for a given IPv6 address.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_resolve_reverse_ipv6().
Parameters:
in an IPv6 address
flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for
this query.
callback a callback function to invoke when the request is
completed
ptr an argument to pass to the callback function
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_resolve_reverse_ipv6()
int evdns_resume (void)
Resume normal operation and continue any suspended resolve requests.
Re-attempt resolves left in limbo after an earlier call to
evdns_clear_nameservers_and_suspend().
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_resume().
Returns:
0 if successful, or -1 if an error occurred
See also:
evdns_clear_nameservers_and_suspend()
void evdns_search_add (const char * domain)
Add a domain to the list of search domains.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_search_add().
Parameters:
domain the domain to be added to the search list
void evdns_search_clear (void)
Clear the list of search domains.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_search_clear().
void evdns_search_ndots_set (const int ndots)
Set the 'ndots' parameter for searches. Sets the number of dots which,
when found in a name, causes the first query to be without any search
domain.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_search_ndots_set().
Parameters:
ndots the new ndots parameter
int evdns_set_option (const char * option, const char * val, int flags)
Set the value of a configuration option. The currently available
configuration options are:
ndots, timeout, max-timeouts, max-inflight, and attempts
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_set_option().
Parameters:
option the name of the configuration option to be modified
val the value to be set
flags Ignored.
Returns:
0 if successful, or -1 if an error occurred
void evdns_shutdown (int fail_requests)
Shut down the asynchronous DNS resolver and terminate all active
requests. If the 'fail_requests' option is enabled, all active requests
will return an empty result with the error flag set to
DNS_ERR_SHUTDOWN. Otherwise, the requests will be silently discarded.
Deprecated
This function is deprecated because it does not allow the caller to
specify which evdns_base it applies to. The recommended function is
evdns_base_shutdown().
Parameters:
fail_requests if zero, active requests will be aborted; if non-
zero, active requests will return DNS_ERR_SHUTDOWN.
See also:
evdns_init()
Author
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libevent Tue Jan 31 2017 evdns_compat(3)