DNS: Separate out CIFS DNS Resolver code
authorWang Lei <wang840925@gmail.com>
Wed, 4 Aug 2010 14:16:33 +0000 (15:16 +0100)
committerSteve French <sfrench@us.ibm.com>
Thu, 5 Aug 2010 17:17:51 +0000 (17:17 +0000)
commit1a4240f4764ac78adbf4b0ebb49b3bd8c72ffa11
tree7d9de5b071e7ab8a8355bdf7902db4c0a0e812b1
parentba5dadbf4e7b531bd7ccecffb4d3935c80a3372e
DNS: Separate out CIFS DNS Resolver code

Separate out the DNS resolver key type from the CIFS filesystem into its own
module so that it can be made available for general use, including the AFS
filesystem module.

This facility makes it possible for the kernel to upcall to userspace to have
it issue DNS requests, package up the replies and present them to the kernel
in a useful form.  The kernel is then able to cache the DNS replies as keys
can be retained in keyrings.

Resolver keys are of type "dns_resolver" and have a case-insensitive
description that is of the form "[<type>:]<domain_name>".  The optional <type>
indicates the particular DNS lookup and packaging that's required.  The
<domain_name> is the query to be made.

If <type> isn't given, a basic hostname to IP address lookup is made, and the
result is stored in the key in the form of a printable string consisting of a
comma-separated list of IPv4 and IPv6 addresses.

This key type is supported by userspace helpers driven from /sbin/request-key
and configured through /etc/request-key.conf.  The cifs.upcall utility is
invoked for UNC path server name to IP address resolution.

The CIFS functionality is encapsulated by the dns_resolve_unc_to_ip() function,
which is used to resolve a UNC path to an IP address for CIFS filesystem.  This
part remains in the CIFS module for now.

See the added Documentation/networking/dns_resolver.txt for more information.

Signed-off-by: Wang Lei <wang840925@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
14 files changed:
Documentation/networking/dns_resolver.txt [new file with mode: 0644]
fs/cifs/Kconfig
fs/cifs/cifsfs.c
fs/cifs/dns_resolve.c
fs/cifs/dns_resolve.h
include/keys/dns_resolver-type.h [new file with mode: 0644]
include/linux/dns_resolver.h [new file with mode: 0644]
net/Kconfig
net/Makefile
net/dns_resolver/Kconfig [new file with mode: 0644]
net/dns_resolver/Makefile [new file with mode: 0644]
net/dns_resolver/dns_key.c [new file with mode: 0644]
net/dns_resolver/dns_query.c [new file with mode: 0644]
net/dns_resolver/internal.h [new file with mode: 0644]