ceph: negotiate authentication protocol; implement AUTH_NONE protocol

When we open a monitor session, we send an initial AUTH message listing
the auth protocols we support, our entity name, and (possibly) a previously
assigned global_id.  The monitor chooses a protocol and responds with an
initial message.

Initially implement AUTH_NONE, a dummy protocol that provides no security,
but works within the new framework.  It generates 'authorizers' that are
used when connecting to (mds, osd) services that simply state our entity
name and global_id.

This is a wire protocol change.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 69feeb1..8a28515 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -8,6 +8,7 @@
 #include "super.h"
 #include "messenger.h"
 #include "decode.h"
+#include "auth.h"
 
 /*
  * A cluster of MDS (metadata server) daemons is responsible for
@@ -274,8 +275,12 @@
 {
 	dout("mdsc put_session %p %d -> %d\n", s,
 	     atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
-	if (atomic_dec_and_test(&s->s_ref))
+	if (atomic_dec_and_test(&s->s_ref)) {
+		if (s->s_authorizer)
+			s->s_mdsc->client->monc.auth->ops->destroy_authorizer(
+				s->s_mdsc->client->monc.auth, s->s_authorizer);
 		kfree(s);
+	}
 }
 
 /*
@@ -2777,9 +2782,15 @@
 
 	ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
 	ceph_decode_copy(&p, &fsid, sizeof(fsid));
-	if (ceph_fsid_compare(&fsid, &mdsc->client->monc.monmap->fsid)) {
-		pr_err("got mdsmap with wrong fsid\n");
-		return;
+        if (mdsc->client->monc.have_fsid) {
+		if (ceph_fsid_compare(&fsid,
+				      &mdsc->client->monc.monmap->fsid)) {
+			pr_err("got mdsmap with wrong fsid\n");
+			return;
+		}
+	} else {
+		ceph_fsid_set(&mdsc->client->monc.monmap->fsid, &fsid);
+		mdsc->client->monc.have_fsid = true;
 	}
 	epoch = ceph_decode_32(&p);
 	maplen = ceph_decode_32(&p);
@@ -2895,10 +2906,60 @@
 	ceph_msg_put(msg);
 }
 
+/*
+ * authentication
+ */
+static int get_authorizer(struct ceph_connection *con,
+			  void **buf, int *len, int *proto,
+			  void **reply_buf, int *reply_len, int force_new)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	struct ceph_auth_client *ac = mdsc->client->monc.auth;
+	int ret = 0;
+
+	if (force_new && s->s_authorizer) {
+		ac->ops->destroy_authorizer(ac, s->s_authorizer);
+		s->s_authorizer = NULL;
+	}
+	if (s->s_authorizer == NULL) {
+		if (ac->ops->create_authorizer) {
+			ret = ac->ops->create_authorizer(
+				ac, CEPH_ENTITY_TYPE_MDS,
+				&s->s_authorizer,
+				&s->s_authorizer_buf,
+				&s->s_authorizer_buf_len,
+				&s->s_authorizer_reply_buf,
+				&s->s_authorizer_reply_buf_len);
+			if (ret)
+				return ret;
+		}
+	}
+
+	*proto = ac->protocol;
+	*buf = s->s_authorizer_buf;
+	*len = s->s_authorizer_buf_len;
+	*reply_buf = s->s_authorizer_reply_buf;
+	*reply_len = s->s_authorizer_reply_buf_len;
+	return 0;
+}
+
+
+static int verify_authorizer_reply(struct ceph_connection *con, int len)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	struct ceph_auth_client *ac = mdsc->client->monc.auth;
+
+	return ac->ops->verify_authorizer_reply(ac, s->s_authorizer, len);
+}
+
 const static struct ceph_connection_operations mds_con_ops = {
 	.get = con_get,
 	.put = con_put,
 	.dispatch = dispatch,
+	.get_authorizer = get_authorizer,
+	.verify_authorizer_reply = verify_authorizer_reply,
 	.peer_reset = peer_reset,
 	.alloc_msg = ceph_alloc_msg,
 	.alloc_middle = ceph_alloc_middle,