draft-ietf-nfsv4-rfc1831bis-05.txt   draft-ietf-nfsv4-rfc1831bis-06.txt 
Network Working Group Robert Thurlow Network Working Group Robert Thurlow
Document: draft-ietf-nfsv4-rfc1831bis-05.txt Document: draft-ietf-nfsv4-rfc1831bis-06.txt
RPC: Remote Procedure Call Protocol Specification Version 2 RPC: Remote Procedure Call Protocol Specification Version 2
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, each author represents that any
patent or other IPR claims of which I am aware have been disclosed, applicable patent or other IPR claims of which he or she is aware
and any of which I become aware will be disclosed, in accordance with have been or will be disclosed, and any of which he or she becomes
RFC 3668. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
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Discussion and suggestions for improvement are requested. This Discussion and suggestions for improvement are requested. This
document will expire in August, 2005. Distribution of this draft is document will expire in August, 2005. Distribution of this draft is
unlimited. unlimited.
Abstract Abstract
This document describes the ONC (Open Network Computing) Remote This document describes the ONC (Open Network Computing) Remote
Procedure Call (ONC RPC Version 2) protocol as it is currently Procedure Call (ONC RPC Version 2) protocol as it is currently
deployed and accepted. It is meant to supersede [RFC1831]. deployed and accepted. It is meant to supersede [RFC1831].
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The RPC Model . . . . . . . . . . . . . . . . . . . . . . . 3 3. The RPC Model . . . . . . . . . . . . . . . . . . . . . . . 3
4. Transports and Semantics . . . . . . . . . . . . . . . . . . 5 4. Transports and Semantics . . . . . . . . . . . . . . . . . . 5
5. Binding and Rendezvous Independence . . . . . . . . . . . . 6 5. Binding and Rendezvous Independence . . . . . . . . . . . . 6
6. Authentication . . . . . . . . . . . . . . . . . . . . . . . 6 6. Authentication . . . . . . . . . . . . . . . . . . . . . . . 6
7. RPC Protocol Requirements . . . . . . . . . . . . . . . . . 6 7. RPC Protocol Requirements . . . . . . . . . . . . . . . . . 6
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7.4.2. Broadcast Remote Procedure Calls . . . . . . . . . . . . 9 7.4.2. Broadcast Remote Procedure Calls . . . . . . . . . . . . 9
8. The RPC Message Protocol . . . . . . . . . . . . . . . . . 10 8. The RPC Message Protocol . . . . . . . . . . . . . . . . . 10
9. Authentication Protocols . . . . . . . . . . . . . . . . . 13 9. Authentication Protocols . . . . . . . . . . . . . . . . . 13
9.1. Null Authentication . . . . . . . . . . . . . . . . . . 14 9.1. Null Authentication . . . . . . . . . . . . . . . . . . 14
10. Record Marking Standard . . . . . . . . . . . . . . . . . 14 10. Record Marking Standard . . . . . . . . . . . . . . . . . 14
11. The RPC Language . . . . . . . . . . . . . . . . . . . . 14 11. The RPC Language . . . . . . . . . . . . . . . . . . . . 14
11.1. An Example Service Described in the RPC Language . . . 15 11.1. An Example Service Described in the RPC Language . . . 15
11.2. The RPC Language Specification . . . . . . . . . . . . 16 11.2. The RPC Language Specification . . . . . . . . . . . . 16
11.3. Syntax Notes . . . . . . . . . . . . . . . . . . . . . 16 11.3. Syntax Notes . . . . . . . . . . . . . . . . . . . . . 16
12. IANA Considerations . . . . . . . . . . . . . . . . . . . 17 12. IANA Considerations . . . . . . . . . . . . . . . . . . . 17
13. Security Considerations . . . . . . . . . . . . . . . . . 17 12.1. Numbering Requests to IANA . . . . . . . . . . . . . . 17
14. Appendix A: System Authentication . . . . . . . . . . . . 17 12.2. Protecting Past Assignments . . . . . . . . . . . . . . 17
12.3. RPC Number Assignment . . . . . . . . . . . . . . . . . 17
12.3.1. To be assigned by IANA . . . . . . . . . . . . . . . 18
12.3.2. Defined by local administrator . . . . . . . . . . . 18
12.3.3. Transient block . . . . . . . . . . . . . . . . . . . 18
12.3.4. Reserved block . . . . . . . . . . . . . . . . . . . 19
12.3.5. RPC Number Sub-Blocks . . . . . . . . . . . . . . . . 19
12.4. RPC Authentication Flavor Number Assignment . . . . . . 20
13. Security Considerations . . . . . . . . . . . . . . . . . 21
14. Appendix A: System Authentication . . . . . . . . . . . . 21
15. Appendix B: Requesting RPC program or authentication 15. Appendix B: Requesting RPC program or authentication
numbers . . . . . . . . . . . . . . . . . . . . . . . . . 18 numbers . . . . . . . . . . . . . . . . . . . . . . . . . 22
16. Full Copyright Statement . . . . . . . . . . . . . . . . 20 16. Full Copyright Statement . . . . . . . . . . . . . . . . 24
17. Intellectual property . . . . . . . . . . . . . . . . . . 20 17. Intellectual property . . . . . . . . . . . . . . . . . . 24
18. Normative References . . . . . . . . . . . . . . . . . . 21 18. Normative References . . . . . . . . . . . . . . . . . . 25
19. Informative References . . . . . . . . . . . . . . . . . 21 19. Informative References . . . . . . . . . . . . . . . . . 25
20. Author's Address . . . . . . . . . . . . . . . . . . . . 23 20. Author's Address . . . . . . . . . . . . . . . . . . . . 27
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
1. Introduction 1. Introduction
This document specifies version two of the message protocol used in This document specifies version two of the message protocol used in
ONC Remote Procedure Call (RPC). The message protocol is specified ONC Remote Procedure Call (RPC). The message protocol is specified
with the eXternal Data Representation (XDR) language [RFC1832]. This with the eXternal Data Representation (XDR) language [RFC1832]. This
document assumes that the reader is familiar with XDR. It does not document assumes that the reader is familiar with XDR. It does not
attempt to justify remote procedure calls systems or describe their attempt to justify remote procedure calls systems or describe their
use. The paper by Birrell and Nelson [XRPC] is recommended as an use. The paper by Birrell and Nelson [XRPC] is recommended as an
excellent background for the remote procedure call concept. excellent background for the remote procedure call concept.
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3. The RPC Model 3. The RPC Model
The ONC RPC protocol is based on the remote procedure call model, The ONC RPC protocol is based on the remote procedure call model,
which is similar to the local procedure call model. In the local which is similar to the local procedure call model. In the local
case, the caller places arguments to a procedure in some well- case, the caller places arguments to a procedure in some well-
specified location (such as a register window). It then transfers specified location (such as a register window). It then transfers
control to the procedure, and eventually regains control. At that control to the procedure, and eventually regains control. At that
point, the results of the procedure are extracted from the well- point, the results of the procedure are extracted from the well-
specified location, and the caller continues execution. specified location, and the caller continues execution.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
The remote procedure call model is similar. One thread of control The remote procedure call model is similar. One thread of control
logically winds through two processes: the caller's process, and a logically winds through two processes: the caller's process, and a
server's process. The caller process first sends a call message to server's process. The caller process first sends a call message to
the server process and waits (blocks) for a reply message. The call the server process and waits (blocks) for a reply message. The call
message includes the procedure's parameters, and the reply message message includes the procedure's parameters, and the reply message
includes the procedure's results. Once the reply message is includes the procedure's results. Once the reply message is
received, the results of the procedure are extracted, and caller's received, the results of the procedure are extracted, and caller's
execution is resumed. execution is resumed.
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o Authentication: since remote procedure calls can be transported o Authentication: since remote procedure calls can be transported
over unsecured networks, authentication may be necessary. over unsecured networks, authentication may be necessary.
Authentication prevents one entity from masquerading as some Authentication prevents one entity from masquerading as some
other entity. other entity.
The conclusion is that even though there are tools to automatically The conclusion is that even though there are tools to automatically
generate client and server libraries for a given service, protocols generate client and server libraries for a given service, protocols
must still be designed carefully. must still be designed carefully.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
4. Transports and Semantics 4. Transports and Semantics
The RPC protocol can be implemented on several different transport The RPC protocol can be implemented on several different transport
protocols. The RPC protocol does not care how a message is passed protocols. The RPC protocol does not care how a message is passed
from one process to another, but only with specification and from one process to another, but only with specification and
interpretation of messages. However, the application may wish to interpretation of messages. However, the application may wish to
obtain information about (and perhaps control over) the transport obtain information about (and perhaps control over) the transport
layer through an interface not specified in this document. For layer through an interface not specified in this document. For
example, the transport protocol may impose a restriction on the example, the transport protocol may impose a restriction on the
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may choose to reuse its previous transaction ID when retransmitting a may choose to reuse its previous transaction ID when retransmitting a
call. The server may choose to remember this ID after executing a call. The server may choose to remember this ID after executing a
call and not execute calls with the same ID in order to achieve some call and not execute calls with the same ID in order to achieve some
degree of execute-at-most-once semantics. The server is not allowed degree of execute-at-most-once semantics. The server is not allowed
to examine this ID in any other way except as a test for equality. to examine this ID in any other way except as a test for equality.
On the other hand, if using a "reliable" transport such as TCP, the On the other hand, if using a "reliable" transport such as TCP, the
application can infer from a reply message that the procedure was application can infer from a reply message that the procedure was
executed exactly once, but if it receives no reply message, it cannot executed exactly once, but if it receives no reply message, it cannot
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
assume that the remote procedure was not executed. Note that even if assume that the remote procedure was not executed. Note that even if
a connection-oriented protocol like TCP is used, an application still a connection-oriented protocol like TCP is used, an application still
needs time-outs and reconnection to handle server crashes. needs time-outs and reconnection to handle server crashes.
There are other possibilities for transports besides datagram- or There are other possibilities for transports besides datagram- or
connection-oriented protocols. For example, a request-reply protocol connection-oriented protocols. For example, a request-reply protocol
such as [VMTP] is perhaps a natural transport for RPC. ONC RPC such as [VMTP] is perhaps a natural transport for RPC. ONC RPC
currently uses both TCP and UDP transport protocols. Section 10 currently uses both TCP and UDP transport protocols. Section 10
(Record Marking Standard) describes the mechanism employed by ONC RPC (Record Marking Standard) describes the mechanism employed by ONC RPC
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The RPC protocol must provide for the following: The RPC protocol must provide for the following:
o Unique specification of a procedure to be called. o Unique specification of a procedure to be called.
o Provisions for matching response messages to request messages. o Provisions for matching response messages to request messages.
o Provisions for authenticating the caller to service and vice- o Provisions for authenticating the caller to service and vice-
versa. versa.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
Besides these requirements, features that detect the following are Besides these requirements, features that detect the following are
worth supporting because of protocol roll-over errors, implementation worth supporting because of protocol roll-over errors, implementation
bugs, user error, and network administration: bugs, user error, and network administration:
o RPC protocol mismatches. o RPC protocol mismatches.
o Remote program protocol version mismatches. o Remote program protocol version mismatches.
o Protocol errors (such as misspecification of a procedure's o Protocol errors (such as misspecification of a procedure's
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The reply message to a request message has enough information to The reply message to a request message has enough information to
distinguish the following error conditions: distinguish the following error conditions:
o The remote implementation of RPC does not support protocol o The remote implementation of RPC does not support protocol
version 2. The lowest and highest supported RPC version numbers version 2. The lowest and highest supported RPC version numbers
are returned. are returned.
o The remote program is not available on the remote system. o The remote program is not available on the remote system.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
o The remote program does not support the requested version o The remote program does not support the requested version
number. The lowest and highest supported remote program version number. The lowest and highest supported remote program version
numbers are returned. numbers are returned.
o The requested procedure number does not exist. (This is usually o The requested procedure number does not exist. (This is usually
a client side protocol or programming error.) a client side protocol or programming error.)
o The parameters to the remote procedure appear to be garbage from o The parameters to the remote procedure appear to be garbage from
the server's point of view. (Again, this is usually caused by a the server's point of view. (Again, this is usually caused by a
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(uninterpreted by) the RPC protocol implementation. (uninterpreted by) the RPC protocol implementation.
The interpretation and semantics of the data contained within the The interpretation and semantics of the data contained within the
authentication fields is specified by individual, independent authentication fields is specified by individual, independent
authentication protocol specifications. (Section 9 defines the authentication protocol specifications. (Section 9 defines the
various authentication protocols.) various authentication protocols.)
If authentication parameters were rejected, the reply message If authentication parameters were rejected, the reply message
contains information stating why they were rejected. contains information stating why they were rejected.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
7.3. Program Number Assignment 7.3. Program Number Assignment
Program numbers are given out in groups of hexadecimal 20000000 Program numbers are given out in groups of hexadecimal 20000000
(decimal 536870912) according to the following chart: (decimal 536870912) according to the following chart:
0 Reserved 0 Reserved
1 - 0x1fffffff To be assigned by IANA 1 - 0x1fffffff To be assigned by IANA
0x20000000 - 0x3fffffff Defined by local administrator 0x20000000 - 0x3fffffff Defined by local administrator
(some blocks assigned here) (some blocks assigned here)
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batch calls is usually terminated by a legitimate remote procedure batch calls is usually terminated by a legitimate remote procedure
call operation in order to flush the pipeline and get positive call operation in order to flush the pipeline and get positive
acknowledgement. acknowledgement.
7.4.2. Broadcast Remote Procedure Calls 7.4.2. Broadcast Remote Procedure Calls
In broadcast protocols, the client sends a broadcast call to the In broadcast protocols, the client sends a broadcast call to the
network and waits for numerous replies. This requires the use of network and waits for numerous replies. This requires the use of
packet-based protocols (like UDP) as its transport protocol. Servers packet-based protocols (like UDP) as its transport protocol. Servers
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
that support broadcast protocols usually respond only when the call that support broadcast protocols usually respond only when the call
is successfully processed and are silent in the face of errors, but is successfully processed and are silent in the face of errors, but
this varies with the application. this varies with the application.
The principles of broadcast RPC also apply to multicasting - an RPC The principles of broadcast RPC also apply to multicasting - an RPC
request can be sent to a multicast address. request can be sent to a multicast address.
8. The RPC Message Protocol 8. The RPC Message Protocol
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enum reject_stat { enum reject_stat {
RPC_MISMATCH = 0, /* RPC version number != 2 */ RPC_MISMATCH = 0, /* RPC version number != 2 */
AUTH_ERROR = 1 /* remote can't authenticate caller */ AUTH_ERROR = 1 /* remote can't authenticate caller */
}; };
Why authentication failed: Why authentication failed:
enum auth_stat { enum auth_stat {
AUTH_OK = 0, /* success */ AUTH_OK = 0, /* success */
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
/* /*
* failed at remote end * failed at remote end
*/ */
AUTH_BADCRED = 1, /* bad credential (seal broken) */ AUTH_BADCRED = 1, /* bad credential (seal broken) */
AUTH_REJECTEDCRED = 2, /* client must begin new session */ AUTH_REJECTEDCRED = 2, /* client must begin new session */
AUTH_BADVERF = 3, /* bad verifier (seal broken) */ AUTH_BADVERF = 3, /* bad verifier (seal broken) */
AUTH_REJECTEDVERF = 4, /* verifier expired or replayed */ AUTH_REJECTEDVERF = 4, /* verifier expired or replayed */
AUTH_TOOWEAK = 5, /* rejected for security reasons */ AUTH_TOOWEAK = 5, /* rejected for security reasons */
/* /*
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struct rpc_msg { struct rpc_msg {
unsigned int xid; unsigned int xid;
union switch (msg_type mtype) { union switch (msg_type mtype) {
case CALL: case CALL:
call_body cbody; call_body cbody;
case REPLY: case REPLY:
reply_body rbody; reply_body rbody;
} body; } body;
}; };
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
Body of an RPC call: Body of an RPC call:
In version 2 of the RPC protocol specification, rpcvers must be equal In version 2 of the RPC protocol specification, rpcvers must be equal
to 2. The fields prog, vers, and proc specify the remote program, to 2. The fields prog, vers, and proc specify the remote program,
its version number, and the procedure within the remote program to be its version number, and the procedure within the remote program to be
called. After these fields are two authentication parameters: cred called. After these fields are two authentication parameters: cred
(authentication credential) and verf (authentication verifier). The (authentication credential) and verf (authentication verifier). The
two authentication parameters are followed by the parameters to the two authentication parameters are followed by the parameters to the
remote procedure, which are specified by the specific program remote procedure, which are specified by the specific program
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order to validate itself to the client. It is followed by a union order to validate itself to the client. It is followed by a union
whose discriminant is an enum accept_stat. The SUCCESS arm of the whose discriminant is an enum accept_stat. The SUCCESS arm of the
union is protocol specific. The PROG_UNAVAIL, PROC_UNAVAIL, union is protocol specific. The PROG_UNAVAIL, PROC_UNAVAIL,
GARBAGE_ARGS, and SYSTEM_ERR arms of the union are void. The GARBAGE_ARGS, and SYSTEM_ERR arms of the union are void. The
PROG_MISMATCH arm specifies the lowest and highest version numbers of PROG_MISMATCH arm specifies the lowest and highest version numbers of
the remote program supported by the server. the remote program supported by the server.
struct accepted_reply { struct accepted_reply {
opaque_auth verf; opaque_auth verf;
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
union switch (accept_stat stat) { union switch (accept_stat stat) {
case SUCCESS: case SUCCESS:
opaque results[0]; opaque results[0];
/* /*
* procedure-specific results start here * procedure-specific results start here
*/ */
case PROG_MISMATCH: case PROG_MISMATCH:
struct { struct {
unsigned int low; unsigned int low;
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9. Authentication Protocols 9. Authentication Protocols
As previously stated, authentication parameters are opaque, but As previously stated, authentication parameters are opaque, but
open-ended to the rest of the RPC protocol. This section defines two open-ended to the rest of the RPC protocol. This section defines two
standard "flavors" of authentication. Implementors are free to standard "flavors" of authentication. Implementors are free to
invent new authentication types, with the same rules of flavor number invent new authentication types, with the same rules of flavor number
assignment as there is for program number assignment. The "flavor" assignment as there is for program number assignment. The "flavor"
of a credential or verifier refers to the value of the "flavor" field of a credential or verifier refers to the value of the "flavor" field
in the opaque_auth structure. Flavor numbers, like RPC program in the opaque_auth structure. Flavor numbers, like RPC program
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
numbers, are also administered centrally, and developers may assign numbers, are also administered centrally, and developers may assign
new flavor numbers by methods described in Appendix B. Credentials new flavor numbers by methods described in Appendix B. Credentials
and verifiers are represented as variable length opaque data (the and verifiers are represented as variable length opaque data (the
"body" field in the opaque_auth structure). "body" field in the opaque_auth structure).
In this document, two flavors of authentication are described. Of In this document, two flavors of authentication are described. Of
these, Null authentication (described in the next subsection) is these, Null authentication (described in the next subsection) is
mandatory - it must be available in all implementations. System mandatory - it must be available in all implementations. System
authentication (AUTH_SYS) is described in Appendix A. It is strongly authentication (AUTH_SYS) is described in Appendix A. It is strongly
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highest-order bit of the header; the length is the 31 low-order bits. highest-order bit of the header; the length is the 31 low-order bits.
(Note that this record specification is NOT in XDR standard form!) (Note that this record specification is NOT in XDR standard form!)
11. The RPC Language 11. The RPC Language
Just as there was a need to describe the XDR data-types in a formal Just as there was a need to describe the XDR data-types in a formal
language, there is also need to describe the procedures that operate language, there is also need to describe the procedures that operate
on these XDR data-types in a formal language as well. The RPC on these XDR data-types in a formal language as well. The RPC
Language is an extension to the XDR language, with the addition of Language is an extension to the XDR language, with the addition of
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
"program", "procedure", and "version" declarations. The following "program", "procedure", and "version" declarations. The following
example is used to describe the essence of the language. example is used to describe the essence of the language.
11.1. An Example Service Described in the RPC Language 11.1. An Example Service Described in the RPC Language
Here is an example of the specification of a simple ping program. Here is an example of the specification of a simple ping program.
program PING_PROG { program PING_PROG {
/* /*
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convention, procedure 0 of any RPC protocol should have the same convention, procedure 0 of any RPC protocol should have the same
semantics, and never require any kind of authentication. The second semantics, and never require any kind of authentication. The second
procedure is used for the client to have the server do a reverse ping 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 operation back to the client, and it returns the amount of time (in
microseconds) that the operation used. The next version, microseconds) that the operation used. The next version,
PING_VERS_ORIG, is the original version of the protocol and it does PING_VERS_ORIG, is the original version of the protocol and it does
not contain PINGPROC_PINGBACK procedure. It is useful for not contain PINGPROC_PINGBACK procedure. It is useful for
compatibility with old client programs, and as this program matures compatibility with old client programs, and as this program matures
it may be dropped from the protocol entirely. it may be dropped from the protocol entirely.
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11.2. The RPC Language Specification 11.2. The RPC Language Specification
The RPC language is identical to the XDR language defined in RFC The RPC language is identical to the XDR language defined in RFC
1014, except for the added definition of a "program-def" described 1014, except for the added definition of a "program-def" described
below. below.
program-def: program-def:
"program" identifier "{" "program" identifier "{"
version-def version-def
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once within the scope of version definition. once within the scope of version definition.
o Program identifiers are in the same name space as constant and o Program identifiers are in the same name space as constant and
type identifiers. type identifiers.
o Only unsigned constants can be assigned to programs, versions o Only unsigned constants can be assigned to programs, versions
and procedures. and procedures.
o Current RPC language compilers do not generally support more o Current RPC language compilers do not generally support more
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
than one type-specifier in procedure argument lists; the usual than one type-specifier in procedure argument lists; the usual
practice is to wrap arguments into a structure. practice is to wrap arguments into a structure.
12. IANA Considerations 12. IANA Considerations
[RPCIANA] proposes to transfer authority over RPC program numbers and The assignment of RPC program numbers and authentication flavor
authentication flavor numbers described here from Sun Microsystems, numbers has in the past been performed by Sun Microsystems, Inc.
Inc. to IANA. This document assumes this transfer. This is inappropriate for an IETF standard protocol, as such work is
done well by the Internet Assigned Numbers Authority (IANA). This
document proposes the transfer of authority over RPC program numbers
and authentication flavor numbers described here from Sun
Microsystems, Inc. to IANA and proposes how IANA will maintain and
assign RPC program numbers and authentication flavor numbers. Users
of RPC protocols will benefit by having an independent body
responsible for RPC number assignments.
12.1. Numbering Requests to IANA
Appendix B of this document describes the information to be sent to
IANA to request one or more RPC numbers and the rules that apply.
IANA should review this part of the document as well.
12.2. Protecting Past Assignments
Sun has made assignments in both number spaces since the original
deployment of RPC. The assignments made by Sun Microsystems are
still valid, and will be preserved. Sun will communicate all current
assignments in both number spaces to IANA before final handoff of
number assignment is done.
12.3. RPC Number Assignment
Future IANA practice should deal with the following partitioning of
the 32-bit number space:
0 Reserved
1 - 0x1fffffff To be assigned by IANA
0x20000000 - 0x3fffffff Defined by local administrator
(see note1)
0x40000000 - 0x5fffffff Transient
0x60000000 - 0x7effffff Reserved
0x7f000000 - 0x7fffffff Assignment outstanding
0x80000000 - 0xffffffff Reserved
Title Remote Procedure Call Protocol Version 2 December 2006
Detailed information for the administration of these blocks is given
below.
12.3.1. To be assigned by IANA
The first block will be administered by IANA, with previous
assignments by Sun protected. Previous assignments were restricted
to the range decimal 100000-399999 (0x000186a0 to 0x00061a7f),
therefore IANA should begin assignments at decimal 400000.
Individual numbers should be grated on a first-come, first-served
basis, and blocks should be granted under rules related to the size
of the block.
12.3.2. Defined by local administrator
The "Defined by local administrator" block is available for any local
administrative domain to use, in a similar manner to IP address
ranges reserved for private use. The expected use would be through
the establishment of a local domain "authority" for assigning numbers
from this range. This authority would establish any policies or
procedures to be used within that local domain for use or assignment
of RPC numbers from the range. The local domain should be
sufficiently isolated that it would be unlikely that RPC applications
developed by other local domains could communicate with the domain.
This could result in RPC number contention, which would cause one of
the applications to fail. In the absence of a local administrator,
this block can be utilized in a "Private Use" manner per [RFC2434].
12.3.3. Transient block
The "Transient" block can be used by any RPC application on a "as
available" basis. This range is intended for services that can
communicate a dynamically selected RPC program number to clients of
the service. Any mechanism can be used to communicate the number.
Examples include shared memory when the client and server are located
on the same system, or a network message (either RPC or otherwise)
that disseminates the selected number.
The transient block is not administered. An RPC service uses this
range by selecting a number in the transient range and attempting to
register that number with the local system's RPC bindery (see the
RPCBPROC_SET or PMAPPROC_SET procedures in "Binding Protocols for ONC
RPC", [RFC1833]). If successful, no other RPC service was using that
number and the RPC Bindery has assigned that number to the requesting
RPC application. The registration is valid until the RPC Bindery
terminates, which normally would only happen if the system reboots
Title Remote Procedure Call Protocol Version 2 December 2006
causing all applications, including the RPC service using the
transient number, to terminate. If the transient number registration
fails, another RPC application is using the number and the requestor
must select another number and try again. To avoid conflicts, the
recommended method is to select a number randomly from the transient
range.
12.3.4. Reserved block
The "Reserved" blocks are available for future use. RPC applications
must not use numbers in these ranges unless their use is allowed by
future action by the IESG.
12.3.5. RPC Number Sub-Blocks
RPC numbers are usually assigned for specific RPC services. Some
applications, however, require multiple RPC numbers for a service.
The most common example is an RPC service that needs to have multiple
instances of the service active simultaneously at a specific site.
RPC does not have an "instance identifier" in the protocol, so either
a mechanism must be implemented to multiplex RPC requests amongst
various instances of the service, or unique RPC numbers must be used
by each instance.
In these cases, the RPC protocol used with the various numbers may be
different or the same. The numbers may be assigned dynamically by
the application, or as part of a site-specific administrative
decision. If possible, RPC services that dynamically assign RPC
numbers should use the "Transient" RPC number block defined in
section 2. If not possible, RPC number sub-blocks may be requested.
Assignment of RPC Number Sub-Blocks is controlled by the size of the
sub-block being requested. "Specification Required" and "IESG
Approval" are used as defined by [RFC2434] Section 2.
Size of sub-block Assignment Method Authority
----------------- ----------------- ---------
Up to 100 numbers First Come First Served IANA
Up to 1000 numbers Specification Required IANA
More than 1000 numbers IESG Approval required IESG
Note: sub-blocks can be any size. The limits given above are
maximums and smaller size sub-blocks are allowed.
Sub-blocks sized up to 100 numbers may be assigned by IANA on a First
Come First Served basis. The RPC Service Description included in the
Title Remote Procedure Call Protocol Version 2 December 2006
range must include an indication of how the sub-block is managed. At
minimum, the statement should indicate whether the sub-block is used
with a single RPC protocol or multiple RPC protocols, and whether the
numbers are dynamically assigned or statically (through
administrative action) assigned.
Sub-blocks of up to 1000 numbers must be documented in detail. The
documentation must describe the RPC protocol or protocols that are to
be used in the range. It must also describe how the numbers within
the sub-block are to be assigned or used.
Sub-blocks sized over 1000 numbers must be documented as described
above, however an Internet Draft must be submitted as an
Informational or Standards Track RFC. If accepted as either, IANA
will assign the requested number sub-block.
In order to avoid multiple requests of large blocks of numbers the
following rule is proposed.
Requests up to and including 100 RPC numbers are handled via the
First Come First Served assignment method. This 100 number
threshhold applies to the total number of RPC numbers assigned to an
individual or entity. For example, if an individual or entity first
requests say 70 numbers, and then later requests 40 numbers, then the
request for the 40 numbers will be assigned via the Specification
Required method. As long as the total number of numbers assigned
does not exceed 1000, IANA is free to waive the Specification
Required assignment for incremental requests of less than 100
numbers.
If an individual or entity has under 1000 numbers and later requests
an additional set of numbers such that the individual or entity would
over 1000 numbers, then the individual or entity will have the
additional request submitted to the IESG. IESG is free to waive the
IESG Action Required assignment method for incremental requests of
less than 1000 numbers.
12.4. RPC Authentication Flavor Number Assignment
The second number space is the authentication mechanism identifier,
or "flavor", number. This number is used to distinguish between
various authentication mechanisms which can be optionally used with
an RPC message. An authentication identifier is used in the "flavor"
field of the "opaque_auth" structure.
Recent progress in RPC security has focused on using the existing
RPCSEC_GSS flavor and inventing novel GSS-API mechanisms which can be
Title Remote Procedure Call Protocol Version 2 December 2006
used with it. Even though RPCSEC_GSS is an assigned authentication
flavor, use of a new RPCSEC_GSS mechanism with NFS ([RFC1094]
[RFC1813] and [RFC3010]) will require the registration of 'pseudo-
flavors' which are used to negotiate security mechanisms in an
unambiguous way, as defined by [RFC2623]. Existing pseudo-flavors
have been granted in the decimal range 390000-390255 as described in
2.2.
For non-pseudo-flavor requests, IANA should begin granting RPC
authentication flavor numbers at 400000 to avoid conflicts with
currently granted numbers.
For authentication flavors to be used on the Internet, it is strongly
advised that an informational or standards-track RFC be published
describing the authentication mechanism behaviour and parameters.
13. Security Considerations 13. Security Considerations
AUTH_SYS as described in Appendix A is known to be insecure due to AUTH_SYS as described in Appendix A is known to be insecure due to
the lack of a verifier to permit the credential to be validated. Use the lack of a verifier to permit the credential to be validated. Use
of AUTH_SYS is not recommended for services which permit clients to of AUTH_SYS is not recommended for services which permit clients to
modify data. modify data.
[RFC2203] defines a new security flavor, RPCSEC_GSS, which permits [RFC2203] defines a new security flavor, RPCSEC_GSS, which permits
GSS-API [RFC2743] mechanisms to be used for securing RPC. All non- GSS-API [RFC2743] mechanisms to be used for securing RPC. All non-
skipping to change at page 17, line 46 skipping to change at page 22, line 4
struct authsys_parms { struct authsys_parms {
unsigned int stamp; unsigned int stamp;
string machinename<255>; string machinename<255>;
unsigned int uid; unsigned int uid;
unsigned int gid; unsigned int gid;
unsigned int gids<16>; unsigned int gids<16>;
}; };
The "stamp" is an arbitrary ID which the caller machine may generate. The "stamp" is an arbitrary ID which the caller machine may generate.
The "machinename" is the name of the caller's machine (like The "machinename" is the name of the caller's machine (like
Title Remote Procedure Call Protocol Version 2 December 2006
"krypton"). The "uid" is the caller's effective user ID. The "gid" "krypton"). The "uid" is the caller's effective user ID. The "gid"
is the caller's effective group ID. The "gids" is a counted array of is the caller's effective group ID. The "gids" is a counted array of
groups which contain the caller as a member. The verifier groups which contain the caller as a member. The verifier
accompanying the credential should have "AUTH_NONE" flavor value accompanying the credential should have "AUTH_NONE" flavor value
(defined above). Note this credential is only unique within a (defined above). Note this credential is only unique within a
particular domain of machine names, uids, and gids. particular domain of machine names, uids, and gids.
Title Remote Procedure Call Protocol Version 2 February 2005
The flavor value of the verifier received in the reply message from The flavor value of the verifier received in the reply message from
the server may be "AUTH_NONE" or "AUTH_SHORT". In the case of the server may be "AUTH_NONE" or "AUTH_SHORT". In the case of
"AUTH_SHORT", the bytes of the reply verifier's string encode an "AUTH_SHORT", the bytes of the reply verifier's string encode an
opaque structure. This new opaque structure may now be passed to the opaque structure. This new opaque structure may now be passed to the
server instead of the original "AUTH_SYS" flavor credential. The server instead of the original "AUTH_SYS" flavor credential. The
server may keep a cache which maps shorthand opaque structures server may keep a cache which maps shorthand opaque structures
(passed back by way of an "AUTH_SHORT" style reply verifier) to the (passed back by way of an "AUTH_SHORT" style reply verifier) to the
original credentials of the caller. The caller can save network original credentials of the caller. The caller can save network
bandwidth and server cpu cycles by using the shorthand credential. bandwidth and server cpu cycles by using the shorthand credential.
skipping to change at page 18, line 35 skipping to change at page 22, line 42
itself. The authentication provided by this scheme can be considered itself. The authentication provided by this scheme can be considered
legitimate only when applications using this scheme and the network legitimate only when applications using this scheme and the network
can be secured externally, and privileged transport addresses are can be secured externally, and privileged transport addresses are
used for the communicating end-points (an example of this is the use used for the communicating end-points (an example of this is the use
of privileged TCP/UDP ports in Unix systems - note that not all of privileged TCP/UDP ports in Unix systems - note that not all
systems enforce privileged transport address mechanisms). systems enforce privileged transport address mechanisms).
15. Appendix B: Requesting RPC program or authentication numbers 15. Appendix B: Requesting RPC program or authentication numbers
RPC numbers which must be unique across all networks are assigned by RPC numbers which must be unique across all networks are assigned by
the Internet Assigned Number Authority. [RPCIANA] describes RPC the Internet Assigned Number Authority. To apply for a single number
program number and authentication flavor number assignment policy to or a block of numbers, electronic mail must be sent to IANA
be implemented by IANA. To apply for a single number or a block of <iana@isi.edu> with the following information:
numbers, electronic mail must be sent to IANA <iana@isi.edu> with the
following information:
o The type of number(s) (program number or authentication flavor o The type of number(s) (program number or authentication flavor
number) sought number) sought
o How many numbers are sought o How many numbers are sought
o The name of person or company which will use the number o The name of person or company which will use the number
o An "identifier string" which associates the number with a o An "identifier string" which associates the number with a
Title Remote Procedure Call Protocol Version 2 December 2006
service service
o Email address of the contact person for the service which will o Email address of the contact person for the service which will
be using the number. be using the number.
o A short description of the purpose and use of the number o A short description of the purpose and use of the number
Title Remote Procedure Call Protocol Version 2 February 2005
o If an authentication flavor number is sought, and the number o If an authentication flavor number is sought, and the number
will be a 'pseudo-flavor' intended for use with RPCSEC_GSS and will be a 'pseudo-flavor' intended for use with RPCSEC_GSS and
NFS, mappings analogous to those in Section 4.2 of [RFC2623] are NFS, mappings analogous to those in Section 4.2 of [RFC2623] are
required. required.
Specific numbers cannot be requested. Numbers are assigned on a Specific numbers cannot be requested. Numbers are assigned on a
First Come First Served basis. First Come First Served basis.
For all RPC authentication flavor numbers to used on the Internet, it For all RPC authentication flavor numbers to used on the Internet, it
is strongly advised that an informational or standards-track RFC be is strongly advised that an informational or standards-track RFC be
published describing the authentication mechanism behaviour and published describing the authentication mechanism behaviour and
parameters. parameters.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
16. Full Copyright Statement 16. Full Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, (THE IETF TRUST)
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE.
17. Intellectual property 17. Intellectual property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
skipping to change at page 21, line 5 skipping to change at page 25, line 5
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf- this standard. Please address the information to the IETF at ietf-
ipr@ietf.org. ipr@ietf.org.
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
18. Normative References 18. Normative References
[RFC1832] [RFC1832]
Srinivasan, R., "XDR: External Data Representation Standard", RFC Srinivasan, R., "XDR: External Data Representation Standard", RFC
1832, Sun Microsystems, Inc., August 1995. 1832, Sun Microsystems, Inc., August 1995.
19. Informative References 19. Informative References
[XRPC] [XRPC]
skipping to change at page 22, line 5 skipping to change at page 26, line 5
Protocol Specification", STD 7, RFC 793, USC/Information Sciences Protocol Specification", STD 7, RFC 793, USC/Information Sciences
Institute, September 1981. Institute, September 1981.
[RFC768] [RFC768]
Postel, J., "User Datagram Protocol", STD 6, RFC 768, USC/Information Postel, J., "User Datagram Protocol", STD 6, RFC 768, USC/Information
Sciences Institute, August 1980. Sciences Institute, August 1980.
[RFC1700] [RFC1700]
Reynolds, J., and Postel, J., "Assigned Numbers", STD 2, RFC 1700, Reynolds, J., and Postel, J., "Assigned Numbers", STD 2, RFC 1700,
Title Remote Procedure Call Protocol Version 2 February 2005 Title Remote Procedure Call Protocol Version 2 December 2006
USC/Information Sciences Institute, October 1994. USC/Information Sciences Institute, October 1994.
[RFC1831] [RFC1831]
R. Srinivasan, "RPC: Remote Procedure Call Protocol Specification R. Srinivasan, "RPC: Remote Procedure Call Protocol Specification
Version 2", RFC1831, August 1995. Version 2", RFC1831, August 1995.
[KERB87] [KERB87]
Miller, S., Neuman, C., Schiller, J., and J. Saltzer, "Section Miller, S., Neuman, C., Schiller, J., and J. Saltzer, "Section
E.2.1: Kerberos Authentication and Authorization System", M.I.T. E.2.1: Kerberos Authentication and Authorization System", M.I.T.
skipping to change at page 22, line 28 skipping to change at page 27, line 5
[KERB88] [KERB88]
Steiner, J., Neuman, C., and J. Schiller, "Kerberos: An Steiner, J., Neuman, C., and J. Schiller, "Kerberos: An
Authentication Service for Open Network Systems", pp. 191-202 in Authentication Service for Open Network Systems", pp. 191-202 in
Usenix Conference Proceedings, Dallas, Texas, February 1988. Usenix Conference Proceedings, Dallas, Texas, February 1988.
[RFC1510] [RFC1510]
Kohl, J. and C. Neuman, "The Kerberos Network Authentication Service Kohl, J. and C. Neuman, "The Kerberos Network Authentication Service
(V5)", RFC 1510, Digital Equipment Corporation, USC/Information (V5)", RFC 1510, Digital Equipment Corporation, USC/Information
Sciences Institute, September 1993. Sciences Institute, September 1993.
[RPCIANA] Title Remote Procedure Call Protocol Version 2 December 2006
R. Thurlow, "RPC Numbering Authority Transfer to IANA",
http://www.ietf.org/internet-drafts/draft-ietf-nfsv4-rpc-iana-03.txt,
February 2005
Title Remote Procedure Call Protocol Version 2 February 2005
20. Author's Address 20. Author's Address
Address comments related to this memorandum to: Address comments related to this memorandum to:
nfsv4-wg@sunroof.eng.sun.com nfsv4-wg@sunroof.eng.sun.com
Robert Thurlow Robert Thurlow
Sun Microsystems, Inc. Sun Microsystems, Inc.
500 Eldorado Boulevard, UBRM05-171 500 Eldorado Boulevard, UBRM05-171
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