lockd: refactor SM_MON mon_name argument encoder

Clean up: introduce a new XDR encoder specifically for the mon_name
argument of SM_MON requests.  This will be updated later to support IPv6
addresses in addition to IPv4 addresses.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 84fd84cb67b7..87bd4e4d65dd 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -18,6 +18,8 @@
 
 #define NLMDBG_FACILITY         NLMDBG_MONITOR
 
+#define XDR_ADDRBUF_LEN         (20)
+
 static struct rpc_clnt *        nsm_create(void);
 
 static struct rpc_program       nsm_program;
@@ -158,6 +160,29 @@ static __be32 *xdr_encode_nsm_string(__be32 *p, char *string)
         return xdr_encode_opaque(p, string, len);
 }
 
+/*
+ * "mon_name" specifies the host to be monitored.
+ *
+ * Linux uses a text version of the IP address of the remote
+ * host as the host identifier (the "mon_name" argument).
+ *
+ * Linux statd always looks up the canonical hostname first for
+ * whatever remote hostname it receives, so this works alright.
+ */
+static __be32 *xdr_encode_mon_name(__be32 *p, struct nsm_args *argp)
+{
+        char    buffer[XDR_ADDRBUF_LEN + 1];
+        char    *name = argp->mon_name;
+
+        if (!nsm_use_hostnames) {
+                snprintf(buffer, XDR_ADDRBUF_LEN,
+                         NIPQUAD_FMT, NIPQUAD(argp->addr));
+                name = buffer;
+        }
+
+        return xdr_encode_nsm_string(p, name);
+}
+
 static __be32 *
 xdr_encode_common(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
 {