Documentation/networking/dns_resolver.rst

1 .. SPDX-License-Identifier: GPL-2.0
9  - Overview.
10  - Compilation.
11  - Setting up.
12  - Usage.
13  - Mechanism.
14  - Debugging.
21 by way of requesting a key of key type dns_resolver.  These queries are
22 upcalled to userspace through /sbin/request-key.
25 request-key.  It is under development and does not yet provide the full feature
42 	CONFIG_DNS_RESOLVER	- tristate "DNS Resolver support"
45 Setting up
48 To set up this facility, the /etc/request-key.conf file must be altered so that
49 /sbin/request-key can appropriately direct the upcalls.  For example, to handle
54 	#OP	TYPE		DESC	CO-INFO	PROGRAM ARG1 ARG2 ARG3 ...
79      may then be cached.  The key description is constructed as a string of the
86      looked up.  The default query type is a straight hostname to IP address
89      The name parameter is not required to be a NUL-terminated string, and its
96      for the default query type it is just a list of comma-separated IPv4 and
100      error code is returned otherwise.  -EKEYREJECTED will be returned if the
103      If _expiry is non-NULL, the expiry time (TTL) of the result will be
106 The kernel maintains an internal keyring in which it caches looked up keys.
121 The dnsresolver module registers a key type called "dns_resolver".  Keys of
129 directed by means of configuration lines in /etc/request-key.conf that tell
130 /sbin/request-key what program to run to instantiate the key.
136 remainder of the string to the key as its payload.
138 The upcall handler program should set the expiry time on the key to that of the
140 the key will be discarded and recreated when the data it holds has expired.
142 dns_query() returns a copy of the value attached to the key, or an error if
145 See <file:Documentation/security/keys/request-key.rst> for further
146 information about request-key function.