SUNRPC: Add rpcauth_list_flavors()

The gss_mech_list_pseudoflavors() function provides a list of
currently registered GSS pseudoflavors.  This list does not include
any non-GSS flavors that have been registered with the RPC client.
nfs4_find_root_sec() currently adds these extra flavors by hand.

Instead, nfs4_find_root_sec() should be looking at the set of flavors
that have been explicitly registered via rpcauth_register().  And,
other areas of code will soon need the same kind of list that
contains all flavors the kernel currently knows about (see below).

Rather than cloning the open-coded logic in nfs4_find_root_sec() to
those new places, introduce a generic RPC function that generates a
full list of registered auth flavors and pseudoflavors.

A new rpc_authops method is added that lists a flavor's
pseudoflavors, if it has any.  I encountered an interesting module
loader loop when I tried to get the RPC client to invoke
gss_mech_list_pseudoflavors() by name.

This patch is a pre-requisite for server trunking discovery, and a
pre-requisite for fixing up the in-kernel mount client to do better
automatic security flavor selection.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 492a36d72829..f25ba922baaf 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -101,6 +101,7 @@ struct rpc_authops {
         struct rpc_cred *       (*crcreate)(struct rpc_auth*, struct auth_cred *, int);
         int                     (*pipes_create)(struct rpc_auth *);
         void                    (*pipes_destroy)(struct rpc_auth *);
+        int                     (*list_pseudoflavors)(rpc_authflavor_t *, int);
 };
 
 struct rpc_credops {
@@ -135,6 +136,7 @@ int			rpcauth_register(const struct rpc_authops *);
 int                     rpcauth_unregister(const struct rpc_authops *);
 struct rpc_auth *       rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);
 void                    rpcauth_release(struct rpc_auth *);
+int                     rpcauth_list_flavors(rpc_authflavor_t *, int);
 struct rpc_cred *       rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int);
 void                    rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 struct rpc_cred *       rpcauth_lookupcred(struct rpc_auth *, int);
diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h
index 332da61cf8b7..a19e2547ae6a 100644
--- a/include/linux/sunrpc/gss_api.h
+++ b/include/linux/sunrpc/gss_api.h
@@ -14,6 +14,7 @@
 
 #ifdef __KERNEL__
 #include <linux/sunrpc/xdr.h>
+#include <linux/sunrpc/msg_prot.h>
 #include <linux/uio.h>
 
 /* The mechanism-independent gss-api context: */
@@ -127,7 +128,7 @@ struct gss_api_mech *gss_mech_get_by_name(const char *);
 struct gss_api_mech *gss_mech_get_by_pseudoflavor(u32);
 
 /* Fill in an array with a list of supported pseudoflavors */
-int gss_mech_list_pseudoflavors(u32 *);
+int gss_mech_list_pseudoflavors(rpc_authflavor_t *, int);
 
 /* Just increments the mechanism's reference count and returns its input: */
 struct gss_api_mech * gss_mech_get(struct gss_api_mech *);