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Module Cf_nameinfo


module Cf_nameinfo: sig .. end
Domain name resolver interface.

Overview

This module is a wrapper over the C interface to the Domain Name Resolver for IPv6 hosts. These functions typically block until network resources respond to remote queries, sometimes within a few milliseconds. Some exceptions are associated with conditions that take several seconds to detect, e.g. no domain name service available.

Two functions are defined: to_address and of_address. Each function takes an optional argument in the form of a record of boolean flags to control the parameters of the query, much in the way the C interface to the getaddrinfo() and getnameinfo() functions work.

Exceptions raised by the to_address and of_address functions are all of variants of type unresolved constructed on the exception Unresolved defined below.

type unresolved =
| EAI_ADDRFAMILY (*Address family not supported for node.*)
| EAI_AGAIN (*Temporary failure in name resolution.*)
| EAI_BADFLAGS (*Invalid value for flags.*)
| EAI_FAIL (*Non-recoverable failure in name resolution.*)
| EAI_FAMILY (*Address family not supported by resolver.*)
| EAI_MEMORY (*Memory allocation failure.*)
| EAI_NODATA (*No address associated with name.*)
| EAI_NONAME (*No name associated with address.*)
| EAI_SERVICE (*Service name not supported for socket type.*)
| EAI_SOCKTYPE (*Socket type not supported.*)
| EAI_BADHINTS (*Bad hints in getaddrinfo().*)
| EAI_PROTOCOL (*Protocol not supported.*)
| EAI_UNKNOWN of int (*Unknown error code.*)

The sum type of exception conditions
exception Unresolved of unresolved
The exception type.
module P: Cf_socket.P  with type AF.tag = unit and type ST.tag = unit
The unspecified socket protocol, used in composing hints. 
val is_specific_socktype : unit Cf_socket.socktype -> 'a Cf_socket.socktype -> bool
Returns true if the socket types are equivalent.
val is_specific_domain : unit Cf_socket.sockaddr -> 'a Cf_socket.domain -> bool
Returns true if the socket address is of the specific domain.
val specialize_sockaddr : unit Cf_socket.sockaddr -> 'a Cf_socket.domain -> 'a Cf_socket.sockaddr
Use specialize_sockaddr sa d to specialize a socket address sa from the unspecified (or unknown) address family into a socket address of the address family associated with the socket domain d. Raises Not_found if the socket address is not of the appropriate address family.

type of_address_flags = {
   ni_nofqdn : bool; (*Return only the nodename for local hosts.*)
   ni_numerichost : bool; (*Return only the numeric form (no DNS query).*)
   ni_namereqd : bool; (*Raise exception unless name in DNS.*)
   ni_numericserv : bool; (*Return only the numeric form (no DNS query).*)
   ni_dgram : bool; (*Use "udp" in getservbyname().*)
}
The type of flags used with the of_address function to control the parameters of queries for host and service names.
val of_address_default_flags : of_address_flags
The default value of flags for the of_address function below (all flags set to false).
val of_address : ?host:int ->
       ?serv:int ->
       ?flags:of_address_flags ->
       'a Cf_socket.sockaddr -> string * string
Use of_address ?host ?serv ?flags sa to resolve the name of the host and the service associated with the socket address sa. If the ?host or ?serv parameters are provided, they are used as the maximum length of the returned host and/or service name, respectively. Returns an pair of strings, the first is the host name and the second is the service name. Raises Unix.Error if there is an error.

type to_address_flags = {
   ai_passive : bool; (*Return a socket address for a listener.*)
   ai_canonname : bool; (*Return the canonical name.*)
   ai_numerichost : bool; (*Require numeric input (no DNS query).*)
}
The type of flags used with the to_address function to control the parameters of queries for host addresses and service numbers.
val to_address_default_flags : to_address_flags
The default value of ai_flags record field for the hints provided to the to_address function below (all flags set to false).

type to_address_arg =
| A_nodename of string (*Unspecified service name.*)
| A_servicename of string (*Unspecified host name.*)
| A_bothnames of string * string (*Host and service names.*)
The argument to the to_address function.

type ('a, 'b) addrinfo = private {
   ai_flags : to_address_flags; (*Query control in hints.*)
   ai_family : 'a Cf_socket.domain; (*The socket address family.*)
   ai_socktype : 'b Cf_socket.socktype; (*The socket type.*)
   ai_protocol : Cf_socket.protocol; (*The socket protocol.*)
   ai_cname : string option; (*The canonical name.*)
   ai_addr : 'a Cf_socket.sockaddr; (*The address.*)
}
The type of elements in the list returned by the to_address function.
val addrinfo_hint : ?flags:to_address_flags ->
       'a Cf_socket.domain ->
       'b Cf_socket.socktype -> Cf_socket.protocol -> ('a, 'b) addrinfo
Construct a hints value for the to_address function.
val addrinfo_default_hint : (unit, unit) addrinfo
The default hints value for the to_address function, .
val to_addresses : ('a, 'b) addrinfo ->
       to_address_arg -> ('a, 'b) addrinfo list
Use to_addresses hint arg to obtain a list of address information records associated with the host name and/or service name provided in the argument arg, using the hints provided in the hint argument.
val to_all_addresses : to_address_arg -> (unit, unit) addrinfo list
Use to_all_address arg to obtain a list of address information records associated with the host name and/or service name provided in the argument arg. The default hints are used.