• Wang Lei's avatar
    DNS: Separate out CIFS DNS Resolver code · 1a4240f4
    Wang Lei authored
    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: default avatarWang Lei <wang840925@gmail.com>
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Acked-by: default avatarJeff Layton <jlayton@redhat.com>
    Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
dns_resolver.h 1.31 KB