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rfc:rfc1833

Network Working Group R. Srinivasan Request for Comments: 1833 Sun Microsystems Category: Standards Track August 1995

              Binding Protocols for ONC RPC Version 2

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

ABSTRACT

 This document describes the binding protocols used in conjunction
 with the ONC Remote Procedure Call (ONC RPC Version 2) protocols.

TABLE OF CONTENTS

 1. Introduction                                               1
 2. RPCBIND Program Protocol                                   2
 2.1 RPCBIND Protocol Specification (in RPC Language)          3
 2.2 RPCBIND Operation                                         9
 2.2.1 RPCBIND Version 3                                       9
 2.2.2 RPCBIND, Version 4                                     10
 3. Port Mapper Program Protocol                              11
 3.1 Port Mapper Protocol Specification (in RPC Language)     11
 3.2 Port Mapper Operation                                    13
 References                                                   14
 Security Considerations                                      14
 Author's Address                                             14

1. Introduction

 This document specifies the binding protocols used in conjunction
 with ONC RPC Version 2.  As a prerequisite, the reader is expected to
 be familiar with [1] and [2] which describe the ONC RPC Version 2 and
 XDR (eXternal Data Representation) protocols.
 An RPC service is identified by its RPC program number, version
 number, and the transport address where it may be reached.  The
 transport address, in turn, consists of a network address and a
 transport selector.  In the case of a service available over TCP/IP
 or UDP/IP, the network address will be an IP address, and the
 transport selector will be a TCP or UDP port number.

Srinivasan Standards Track [Page 1] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

 A client program needs to know the RPC program number, version
 number, and the transport address corresponding to a service in order
 to utilize the service.  Of these, the RPC program number and version
 number are usually built into the client program, as part of the
 service definition.  The network address component of the transport
 address is usually available in a name service, or is given as a
 parameter to the client program.  The transport selector (ie., the
 TCP or UDP port) is usually determined dynamically, and varies with
 each invocation of the service.  Server programs allocate a transport
 address, and register it with a well-known lookup service (well-known
 because it uses a fixed transport selector, and resides at the same
 network address as the server).  Client programs consult the lookup
 service in order to obtain the server's transport address.
 Such a lookup service is very desirable because the range of well-
 known transport selectors is very small for some transports and the
 number of services is potentially very large.  By running only the
 lookup service on a well-known transport selector, the transport
 addresses of other remote programs can be ascertained by querying the
 lookup service.
 This document describes three versions of a lookup service, all of
 which use the same RPC program number (100000).  They all use port
 111 over TCP and UDP transports.  Versions 3 and 4 are described in
 Section 2 ("RPCBIND Program Protocol").  Version 2 is described in
 Section 3 ("Port Mapper Program Protocol").
 The distinguishing characteristic of RPCBIND (versions 3 and 4) is
 that this protocol uses a transport-independent format for the
 transport address, known as the universal address format.  An address
 in universal address format is an ASCII string representation of the
 transport dependent address.  String representation of addresses
 corresponding to a transport are defined by the addressing authority
 for the transport.  The RPCBIND protocol can be used for binding ONC
 RPC clients and servers over any transport.
 The Port Mapper (version 2), on the other hand, is an older protocol
 that is specific to TCP and UDP.  It handles TCP and UDP ports
 directly.

2. RPCBIND Program Protocol

 The RPCBIND program maps RPC program and version numbers to universal
 addresses, thus making dynamic binding of remote programs possible.
 The RPCBIND program is bound to a well-known address of each
 supported transport, and other programs register their dynamically
 allocated transport address with it.  The RPCBIND program then makes

Srinivasan Standards Track [Page 2] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

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

2.1 RPCBIND Protocol Specification (in RPC Language)

/* * rpcb_prot.x * rpcbind protocol, versions 3 and 4, in RPC Language */

/* * rpcbind address for TCP/UDP */ const RPCB_PORT = 111;

/* * A mapping of (program, version, network ID) to address * * The network identifier (r_netid): * This is a string that represents a local identification for a * network. This is defined by a system administrator based on local * conventions, and cannot be depended on to have the same value on * every system. */ struct rpcb { unsigned long r_prog; /* program number */ unsigned long r_vers; /* version number */ string r_netid<>; /* network id */ string r_addr<>; /* universal address */ string r_owner<>; /* owner of this service */ };

struct rplist { rpcb rpcb_map; struct rplist *rpcb_next; };

Srinivasan Standards Track [Page 3] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

typedef rp__list *rpcblist_ptr; /* results of RPCBPROC_DUMP */

/* * Arguments of remote calls */ struct rpcb_rmtcallargs { unsigned long prog; /* program number */ unsigned long vers; /* version number */ unsigned long proc; /* procedure number */ opaque args<>; /* argument */ };

/* * Results of the remote call */ struct rpcb_rmtcallres { string addr<>; /* remote universal address */ opaque results<>; /* result */ };

/* * rpcb_entry contains a merged address of a service on a particular * transport, plus associated netconfig information. A list of * rpcb_entry items is returned by RPCBPROC_GETADDRLIST. The meanings * and values used for the r_nc_* fields are given below. * * The network identifier (r_nc_netid):

* This is a string that represents a local identification for a * network. This is defined by a system administrator based on * local conventions, and cannot be depended on to have the same * value on every system. * * Transport semantics (r_nc_semantics): * This represents the type of transport, and has the following values: * NC_TPI_CLTS (1) Connectionless * NC_TPI_COTS (2) Connection oriented * NC_TPI_COTS_ORD (3) Connection oriented with graceful close * NC_TPI_RAW (4) Raw transport * * Protocol family (r_nc_protofmly): * This identifies the family to which the protocol belongs. The * following values are defined: * NC_NOPROTOFMLY "-" * NC_LOOPBACK "loopback"

Srinivasan Standards Track [Page 4] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

* NC_INET "inet" * NC_IMPLINK "implink" * NC_PUP "pup" * NC_CHAOS "chaos" * NC_NS "ns" * NC_NBS "nbs" * NC_ECMA "ecma" * NC_DATAKIT "datakit" * NC_CCITT "ccitt" * NC_SNA "sna" * NC_DECNET "decnet" * NC_DLI "dli" * NC_LAT "lat" * NC_HYLINK "hylink" * NC_APPLETALK "appletalk" * NC_NIT "nit" * NC_IEEE802 "ieee802" * NC_OSI "osi" * NC_X25 "x25" * NC_OSINET "osinet" * NC_GOSIP "gosip" * * Protocol name (r_nc_proto): * This identifies a protocol within a family. The following are * currently defined: * NC_NOPROTO "-" * NC_TCP "tcp" * NC_UDP "udp" * NC_ICMP "icmp" */ struct rpcb_entry { string r_maddr<>; /* merged address of service */ string r_nc_netid<>; /* netid field */ unsigned long r_nc_semantics; /* semantics of transport */ string r_nc_protofmly<>; /* protocol family */ string r_nc_proto<>; /* protocol name */ };

/* * A list of addresses supported by a service. */ struct rpcb_entry_list { rpcb_entry rpcb_entry_map; struct rpcb_entry_list *rpcb_entry_next; };

typedef rpcb_entry_list *rpcb_entry_list_ptr;

Srinivasan Standards Track [Page 5] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

/* * rpcbind statistics */

const rpcb_highproc_2 = RPCBPROC_CALLIT; const rpcb_highproc_3 = RPCBPROC_TADDR2UADDR; const rpcb_highproc_4 = RPCBPROC_GETSTAT;

const RPCBSTAT_HIGHPROC = 13; /* # of procs in rpcbind V4 plus one */ const RPCBVERS_STAT = 3; /* provide only for rpcbind V2, V3 and V4 */ const RPCBVERS_4_STAT = 2; const RPCBVERS_3_STAT = 1; const RPCBVERS_2_STAT = 0;

/* Link list of all the stats about getport and getaddr */ struct rpcbs_addrlist { unsigned long prog; unsigned long vers; int success; int failure; string netid<>; struct rpcbs_addrlist *next; };

/* Link list of all the stats about rmtcall */ struct rpcbs_rmtcalllist { unsigned long prog; unsigned long vers; unsigned long proc; int success; int failure; int indirect; /* whether callit or indirect */ string netid<>; struct rpcbs_rmtcalllist *next; };

typedef int rpcbs_proc[RPCBSTAT_HIGHPROC]; typedef rpcbs_addrlist *rpcbs_addrlist_ptr; typedef rpcbs_rmtcalllist *rpcbs_rmtcalllist_ptr;

struct rpcb_stat { rpcbs_proc info; int setinfo; int unsetinfo; rpcbs_addrlist_ptr addrinfo; rpcbs_rmtcalllist_ptr rmtinfo; };

Srinivasan Standards Track [Page 6] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

/* * One rpcb_stat structure is returned for each version of rpcbind * being monitored. */

typedef rpcb_stat rpcb_stat_byvers[RPCBVERS_STAT];

/* * netbuf structure, used to store the transport specific form of * a universal transport address. */ struct netbuf { unsigned int maxlen; opaque buf<>; };

/* * rpcbind procedures */ program RPCBPROG { version RPCBVERS {

   bool
   RPCBPROC_SET(rpcb) = 1;
   bool
   RPCBPROC_UNSET(rpcb) = 2;
   string
   RPCBPROC_GETADDR(rpcb) = 3;
   rpcblist_ptr
   RPCBPROC_DUMP(void) = 4;
   rpcb_rmtcallres
   RPCBPROC_CALLIT(rpcb_rmtcallargs) = 5;
   unsigned int
   RPCBPROC_GETTIME(void) = 6;
   netbuf
   RPCBPROC_UADDR2TADDR(string) = 7;
   string
   RPCBPROC_TADDR2UADDR(netbuf) = 8;

} = 3;

Srinivasan Standards Track [Page 7] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

version RPCBVERS4 {

   bool
   RPCBPROC_SET(rpcb) = 1;
   bool
   RPCBPROC_UNSET(rpcb) = 2;
   string
   RPCBPROC_GETADDR(rpcb) = 3;
   rpcblist_ptr
   RPCBPROC_DUMP(void) = 4;
   /*
    * NOTE: RPCBPROC_BCAST has the same functionality as CALLIT;
    * the new name is intended to indicate that this
    * procedure should be used for broadcast RPC, and
    * RPCBPROC_INDIRECT should be used for indirect calls.
    */
   rpcb_rmtcallres
   RPCBPROC_BCAST(rpcb_rmtcallargs) = RPCBPROC_CALLIT;
   unsigned int
   RPCBPROC_GETTIME(void) = 6;
   netbuf
   RPCBPROC_UADDR2TADDR(string) = 7;
   string
   RPCBPROC_TADDR2UADDR(netbuf) = 8;
   string
   RPCBPROC_GETVERSADDR(rpcb) = 9;
   rpcb_rmtcallres
   RPCBPROC_INDIRECT(rpcb_rmtcallargs) = 10;
   rpcb_entry_list_ptr
   RPCBPROC_GETADDRLIST(rpcb) = 11;
   rpcb_stat_byvers
   RPCBPROC_GETSTAT(void) = 12;

} = 4; } = 100000;

Srinivasan Standards Track [Page 8] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

2.2 RPCBIND Operation

 RPCBIND is contacted by way of an assigned address specific to the
 transport being used.  For TCP/IP and UDP/IP, for example, it is port
 number 111.  Each transport has such an assigned, well-known address.
 The following is a description of each of the procedures supported by
 RPCBIND.

2.2.1 RPCBIND Version 3

 RPCBPROC_SET:
 When a program first becomes available on a machine, it registers
 itself with RPCBIND running on the same machine.  The program passes
 its program number "r_prog", version number "r_vers", network
 identifier "r_netid", universal address "r_addr", and the owner of
 the service "r_owner".  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 ordered set ("r_prog",
 "r_vers", "r_netid").  Note that neither "r_netid" nor "r_addr" can
 be NULL, and that "r_netid" should be a valid network identifier on
 the machine making the call.
 RPCBPROC_UNSET:
 When a program becomes unavailable, it should unregister itself with
 the RPCBIND program on the same machine.  The parameters and results
 have meanings identical to those of RPCBPROC_SET.  The mapping of the
 ("r_prog", "r_vers", "r_netid") tuple with "r_addr" is deleted.  If
 "r_netid" is NULL, all mappings specified by the ordered set
 ("r_prog", "r_vers", *) and the corresponding universal addresses are
 deleted.  Only the owner of the service or the super-user is allowed
 to unset a service.
 RPCBPROC_GETADDR:
 Given a program number "r_prog", version number "r_vers", and network
 identifier  "r_netid", this procedure returns the universal address
 on which the program is awaiting call requests.  The "r_netid" field
 of the argument is ignored and the "r_netid" is inferred from the
 network identifier of the transport on which the request came in.
 RPCBPROC_DUMP:
 This procedure lists all entries in RPCBIND's database.  The
 procedure takes no parameters and returns a list of program, version,
 network identifier, and universal addresses.

Srinivasan Standards Track [Page 9] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

 RPCBPROC_CALLIT:
 This procedure allows a caller to call another remote procedure on
 the same machine without knowing the remote procedure's universal
 address.  It is intended for supporting broadcasts to arbitrary
 remote programs via RPCBIND's universal address.  The parameters
 "prog", "vers", "proc", and args are the program number, version
 number, procedure number, and parameters of the remote procedure.
 Note - This procedure only sends a response if the procedure was
 successfully executed and is silent (no response) otherwise.
 The procedure returns the remote program's universal address, and the
 results of the remote procedure.
 RPCBPROC_GETTIME:
 This procedure returns the local time on its own machine in seconds
 since the midnight of the First day of January, 1970.
 RPCBPROC_UADDR2TADDR:
 This procedure converts universal addresses to transport specific
 addresses.
 RPCBPROC_TADDR2UADDR:
 This procedure converts transport specific addresses to universal
 addresses.

2.2.2 RPCBIND, Version 4

 Version 4 of the RPCBIND protocol includes all of the above
 procedures, and adds several additional ones.
 RPCBPROC_BCAST:
 This procedure is identical to the version 3 RPCBPROC_CALLIT
 procedure.  The new name indicates that the procedure should be used
 for broadcast RPCs only.  RPCBPROC_INDIRECT, defined below, should be
 used for indirect RPC calls.
 RPCBPROC_GETVERSADDR:
 This procedure is similar to RPCBPROC_GETADDR.  The difference is the
 "r_vers" field of the rpcb structure can be used to specify the
 version of interest.  If that version is not registered, no address
 is returned.

Srinivasan Standards Track [Page 10] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

 RPCBPROC_INDIRECT:
 Similar to RPCBPROC_CALLIT.  Instead of being silent about errors
 (such as the program not being registered on the system), this
 procedure returns an indication of the error.  This procedure should
 not be used for broadcast RPC. It is intended to be used with
 indirect RPC calls only.
 RPCBPROC_GETADDRLIST:
 This procedure returns a list of addresses for the given rpcb entry.
 The client may be able use the results to determine alternate
 transports that it can use to communicate with the server.
 RPCBPROC_GETSTAT:
 This procedure returns statistics on the activity of the RPCBIND
 server.  The information lists the number and kind of requests the
 server has received.
 Note - All procedures except RPCBPROC_SET and RPCBPROC_UNSET can be
 called by clients running on a machine other than a machine on which
 RPCBIND is running.  RPCBIND only accepts RPCBPROC_SET and
 RPCBPROC_UNSET requests by clients running on the same machine as the
 RPCBIND program.

3. 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.  The port mapper protocol differs from
 the newer RPCBIND protocols in that it is transport specific in its
 address handling.

3.1 Port Mapper Protocol Specification (in RPC Language)

    const PMAP_PORT = 111;      /* portmapper port number */
 A mapping of (program, version, protocol) to port number:
    struct mapping {
       unsigned int prog;
       unsigned int vers;
       unsigned int prot;
       unsigned int port;
    };

Srinivasan Standards Track [Page 11] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

 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;
          bool
          PMAPPROC_SET(mapping)       = 1;
          bool
          PMAPPROC_UNSET(mapping)     = 2;
          unsigned int
          PMAPPROC_GETPORT(mapping)   = 3;
          pmaplist
          PMAPPROC_DUMP(void)         = 4;
          call_result

Srinivasan Standards Track [Page 12] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

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

3.2 Port Mapper Operation

 The portmapper program currently supports two protocols (UDP and
 TCP).  The portmapper is contacted by talking to it on assigned port
 number 111 (SUNRPC) 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 reply 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.
 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.

Srinivasan Standards Track [Page 13] RFC 1833 Binding Protocols for ONC RPC Version 2 August 1995

 PMAPPROC_CALLIT:
 This procedure allows a client 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 reply if the procedure was
    successfully executed and is silent (no reply) otherwise.
    (2) The port mapper communicates with the remote program using UDP
    only.
 The procedure returns the remote program's port number, and the reply
 is the reply of the remote procedure.

References

 [1]  Srinivasan, R., "Remote Procedure Call Protocol Version 2",
      RFC 1831, Sun Microsystems, Inc., August 1995.
 [2]  Srinivasan, R., "XDR: External Data Representation Standard",
      RFC 1832, Sun Microsystems, Inc., August 1995.

Security Considerations

 Security issues are not discussed in this memo.

Author's Address

 Raj Srinivasan
 Sun Microsystems, Inc.
 ONC Technologies
 2550 Garcia Avenue
 M/S MTV-5-40
 Mountain View, CA  94043
 USA
 Phone: 415-336-2478
 Fax:   415-336-6015
 EMail: raj@eng.sun.com

Srinivasan Standards Track [Page 14]

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