rfc1050.txt

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RFC 1050                 Remote Procedure Call                April 1988


                */
               int
               PINGPROC_PINGBACK(void) = 1;
            } = 2;

            /*
             * Original version
             */
            version PING_VERS_ORIG {
               void
               PINGPROC_NULL(void) = 0;
            } = 1;
         } = 1;

         const PING_VERS = 2;      /* latest version */

   The first version described is PING_VERS_PINGBACK with two
   procedures, PINGPROC_NULL and PINGPROC_PINGBACK.  PINGPROC_NULL takes
   no arguments and returns no results, but it is useful for computing
   round-trip times from the client to the server and back again.  By
   convention, procedure 0 of any RPC protocol should have the same
   semantics, and never require any kind of authentication.  The second
   procedure is used for the client to have the server do a reverse ping
   operation back to the client, and it returns the amount of time (in
   microseconds) that the operation used.  The next version,
   PING_VERS_ORIG, is the original version of the protocol and it does
   not contain PINGPROC_PINGBACK procedure.  It is useful for
   compatibility with old client programs, and as this program matures
   it may be dropped from the protocol entirely.

11.1 The RPC Language Specification

   The RPC language is identical to the XDR language, except for the
   added definition of a "program-def" described below.

      program-def:
         "program" identifier "{"
             version-def
             version-def *
         "}" "=" constant ";"

      version-def:
         "version" identifier "{"
             procedure-def
             procedure-def *
         "}" "=" constant ";"

      procedure-def:



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RFC 1050                 Remote Procedure Call                April 1988


         type-specifier identifier "(" type-specifier ")"
         "=" constant ";"

11.2 Syntax Notes

   (1) The following keywords are added and cannot be used as
       identifiers:  "program" and "version";

   (2) A version name cannot occur more than once within the scope
       of a program definition.  Nor can a version number occur more
       than once within the scope of a program definition.

   (3) A procedure name cannot occur more than once within the scope
       of a version definition.  Nor can a procedure number occur
       more than once within the scope of version definition.

   (4) Program identifiers are in the same name space as constant
       and type identifiers.

   (5) Only unsigned constants can be assigned to programs, versions,
       and procedures.

APPENDIX A: PORT MAPPER PROGRAM PROTOCOL

   The port mapper program maps RPC program and version numbers to
   transport-specific port numbers.  This program makes dynamic binding
   of remote programs possible.

   This is desirable because the range of reserved port numbers is very
   small, and the number of potential remote programs is very large.  By
   running only the port mapper on a reserved port, the port numbers of
   other remote programs can be ascertained by querying the port mapper.

   The port mapper also aids in broadcast RPC.  A given RPC program will
   usually have different port number bindings on different machines, so
   there is no way to directly broadcast to all of these programs.  The
   port mapper, however, does have a fixed port number.  So, to
   broadcast to a given program, the client actually sends its message
   to the port mapper located at the broadcast address.  Each port
   mapper that picks up the broadcast then calls the local service
   specified by the client.  When the port mapper gets the reply from
   the local service, it sends the reply on back to the client.

A.1 Port Mapper Protocol Specification (in RPC Language)


      const PMAP_PORT = 111;      /* portmapper port number */




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RFC 1050                 Remote Procedure Call                April 1988


      /*
       * A mapping of (program, version, protocol) to port number
       */
      struct mapping {
         unsigned int prog;
         unsigned int vers;
         unsigned int prot;
         unsigned int port;
      };

      /*
       * Supported values for the "prot" field
       */
      const IPPROTO_TCP = 6;      /* protocol number for TCP/IP */
      const IPPROTO_UDP = 17;     /* protocol number for UDP/IP */

      /*
       * A list of mappings
       */
      struct *pmaplist {
         mapping map;
         pmaplist next;
      };
      /*
       * Arguments to callit
       */
      struct call_args {
         unsigned int prog;
         unsigned int vers;
         unsigned int proc;
         opaque args<>;
      };
      /*
       * Results of callit
       */
      struct call_result {
         unsigned int port;
         opaque res<>;
      };

     /*
      * Port mapper procedures
      */
      program PMAP_PROG {
         version PMAP_VERS {
            void
            PMAPPROC_NULL(void)         = 0;




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RFC 1050                 Remote Procedure Call                April 1988


            bool
            PMAPPROC_SET(mapping)       = 1;

            bool
            PMAPPROC_UNSET(mapping)     = 2;

            unsigned int
            PMAPPROC_GETPORT(mapping)   = 3;

            pmaplist
            PMAPPROC_DUMP(void)         = 4;

            call_result
            PMAPPROC_CALLIT(call_args)  = 5;
         } = 2;
      } = 100000;

A.2 Port Mapper Operation

   The portmapper program currently supports two protocols (UDP/IP and
   TCP/IP).  The portmapper is contacted by talking to it on assigned
   port number 111 (SUNRPC [8]) on either of these protocols.  The
   following is a description of each of the portmapper procedures:

      PMAPPROC_NULL:

         This procedure does no work.  By convention, procedure zero of
         any protocol takes no parameters and returns no results.

      PMAPPROC_SET:

         When a program first becomes available on a machine, it
         registers itself with the port mapper program on the same
         machine.  The program passes its program number "prog", version
         number "vers", transport protocol number "prot", and the port
         "port" on which it awaits service request.  The procedure
         returns a boolean response whose value is "TRUE" if the
         procedure successfully established the mapping and "FALSE"
         otherwise.  The procedure refuses to establish a mapping if one
         already exists for the tuple "(prog, vers, prot)".

      PMAPPROC_UNSET:

         When a program becomes unavailable, it should unregister itself
         with the port mapper program on the same machine.  The
         parameters and results have meanings identical to those of
         "PMAPPROC_SET".  The protocol and port number fields of the
         argument are ignored.



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RFC 1050                 Remote Procedure Call                April 1988


      PMAPPROC_GETPORT:

         Given a program number "prog", version number "vers", and
         transport protocol number "prot", this procedure returns the
         port number on which the program is awaiting call requests.  A
         port value of zeros means the program has not been registered.
         The "port" field of the argument is ignored.

      PMAPPROC_DUMP:

         This procedure enumerates all entries in the port mapper's
         database.  The procedure takes no parameters and returns a list
         of program, version, protocol, and port values.

      PMAPPROC_CALLIT:

         This procedure allows a caller to call another remote procedure
         on the same machine without knowing the remote procedure's port
         number.  It is intended for supporting broadcasts to arbitrary
         remote programs via the well-known port mapper's port.  The
         parameters "prog", "vers", "proc", and the bytes of "args" are
         the program number, version number, procedure number, and
         parameters of the remote procedure.  Note:

            (1) This procedure only sends a response if the procedure
                 was successfully executed and is silent (no response)
                 otherwise.

            (2) The port mapper communicates with the remote program
                using UDP/IP only.

         The procedure returns the remote program's port number, and the
         bytes of results are the results of the remote procedure.

REFERENCES

   [1]  Birrel, A. D., and Nelson, B. J., "Implementing Remote
        Procedure Calls", XEROX CSL-83-7, October 1983.

   [2]  Cheriton, D., "VMTP: Versatile Message Transaction Protocol",
        Version 0.7, RFC-1045, Stanford University, February 1988.

   [3]  Diffie & Hellman, "Net Directions in Cryptography", IEEE
        Transactions on Information Theory IT-22, November 1976.

   [4]  Postel, J., and Harrenstien, K., "Time Protocol", RFC-868,
        Network Information Center, SRI, May 1983.




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RFC 1050                 Remote Procedure Call                April 1988


   [5]  National Bureau of Standards, "Data Encryption Standard",
        Federal Information Processing Standards Publication 46,
        January 1977.

   [6]  Postel, J., "Transmission Control Protocol - DARPA Internet
        Program Protocol Specification", RFC-793; Network Information
        Center, SRI, September 1981.

   [7]  Postel, J., "User Datagram Protocol", RFC-768, Network
        Information Center, SRI, August 1980.

   [8]  Reynolds, J. and Postel, J.; "Assigned Numbers", RFC-1010,
        Network Information Center, SRI, May 1987.

   [9]  Sun Microsystems; "XDR:  External Data Representation
        Standard", RFC-1014; Sun Microsystems, June 1987.



































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