1 files changed, 40 insertions, 0 deletions

diff --git a/include/linux/sunrpc/msg_prot.h b/include/linux/sunrpc/msg_prot.h
index 8d10d148834e..1e65f2dd80e5 100644
--- a/include/linux/sunrpc/msg_prot.h
+++ b/include/linux/sunrpc/msg_prot.h
@@ -11,6 +11,9 @@
 
 #define RPC_VERSION 2
 
+/* size of an XDR encoding unit in bytes, i.e. 32bit */
+#define XDR_UNIT        (4)
+
 /* spec defines authentication flavor as an unsigned 32 bit integer */
 typedef u32     rpc_authflavor_t;
 
@@ -34,6 +37,9 @@ enum rpc_auth_flavors {
         RPC_AUTH_GSS_SPKMP = 390011,
 };
 
+/* Maximum size (in bytes) of an rpc credential or verifier */
+#define RPC_MAX_AUTH_SIZE (400)
+
 enum rpc_msg_type {
         RPC_CALL = 0,
         RPC_REPLY = 1
@@ -101,5 +107,39 @@ typedef __be32	rpc_fraghdr;
 #define RPC_FRAGMENT_SIZE_MASK          (~RPC_LAST_STREAM_FRAGMENT)
 #define RPC_MAX_FRAGMENT_SIZE           ((1U << 31) - 1)
 
+/*
+ * RPC call and reply header size as number of 32bit words (verifier
+ * size computed separately, see below)
+ */
+#define RPC_CALLHDRSIZE         (6)
+#define RPC_REPHDRSIZE          (4)
+
+
+/*
+ * Maximum RPC header size, including authentication,
+ * as number of 32bit words (see RFCs 1831, 1832).
+ *
+ *      xid                         1 xdr unit = 4 bytes
+ *      mtype                       1
+ *      rpc_version                 1
+ *      program                     1
+ *      prog_version                1
+ *      procedure                   1
+ *      cred {
+ *          flavor                  1
+ *          length                  1
+ *          body<RPC_MAX_AUTH_SIZE> 100 xdr units = 400 bytes
+ *      }
+ *      verf {
+ *          flavor                  1
+ *          length                  1
+ *          body<RPC_MAX_AUTH_SIZE> 100 xdr units = 400 bytes
+ *      }
+ *      TOTAL                       210 xdr units = 840 bytes
+ */
+#define RPC_MAX_HEADER_WITH_AUTH \
+        (RPC_CALLHDRSIZE + 2*(2+RPC_MAX_AUTH_SIZE/4))
+
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_MSGPROT_H_ */