Internet Draft Curtis Villamizar
Expires March 1, 2000 Avici Systems
draft-ietf-rps-dist-03.txt Cengiz Alaettinoglu
ISI
Ramesh Govindan
ISI
David M. Meyer
Cisco
August 31, 1999
Routing Policy System Replication
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
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Copyright (C) The Internet Society (August 31, 1999). All Rights
Reserved.
Abstract
The RIPE database specifications and RPSL define languages used as
the basis for representing information in a routing policy system. A
repository for routing policy system information is known as a routing
registry. A routing registry provides a means of exchanging informa-
Internet Draft Routing Policy System Replication August 31, 1999
tion needed to address many issues of importance to the operation of
the Internet. The implementation and deployment of a routing policy
system must maintain some degree of integrity to be of any use. The
Routing Policy System Security RFC [3] addresses the need to assure
integrity of the data by proposing an authentication and authoriza-
tion model. This document addresses the need to distribute data over
multiple repositories and delegate authority for data subsets to other
repositories without compromising the authorization model established
in Routing Policy System Security RFC.
1 Overview
A routing registry must maintain some degree of integrity to be of any
use. The IRR is increasingly used for purposes that have a stronger
requirement for data integrity and security. There is also a desire
to further decentralize the IRR. This document proposes a means of
decentralizing the routing registry in a way that is consistent with
the usage of the IRR and which avoids compromising data integrity and
security even if the IRR is distributed among less trusted reposito-
ries.
Two methods of authenticating the routing registry information have
been proposed.
authorization and authentication checks on transactions: The integri-
ty of the routing registry data is insured by repeating authoriza-
tion checks as transactions are processed. As transactions are
flooded each remote registry has the option to repeat the autho-
rization and authentication checks. This scales with the total
number of changes to the registry regardless of how many registries
exist. When querying, the integrity of the repository must be such
that it can be trusted. If an organization is unwilling to trust
any of the available repositories or mirrors they have the option
to run their own mirror and repeat authorization checks at that
mirror site. Queries can then be directed to a mirror under their
own administration which presumably can be trusted.
signing routing registry objects: An alternate which appears on the
surface to be attractive is signing the objects themselves. Closer
examination reveals that the approach of signing objects by itself
is flawed and when used in addition to signing transactions and
rechecking authorizations as changes are made adds nothing. In
order for an insertion of critical objects such as inetnums and
routes to be valid, authorization checks must be made which allow
the insertion. The objects on which those authorization checks are
made may later change. In order to later repeat the authorization
checks the state of other objects, possibly in other repositories
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would have to be known. If the repository were not trusted then
the change history on the object would have to be traced back to
the object's insertion. If the repository were not trusted, the
change history of any object that was depended upon for autho-
rization would also have to be rechecked. This trace back would
have to go back to the epoch or at least to a point where only
trusted objects were being relied upon for the authorizations. If
the depth of the search is at all limited, authorization could be
falsified simply by exceeding the search depth with a chain of au-
thorization references back to falsified objects. This would be
grossly inefficient. Simply verifying that an object is signed
provides no assurance that addition of the object addition was
properly authorized.
A minor distinction is made between a repository and a mirror. A
repository has responsibility for the initial authorization and au-
thentication checks for transactions related to its local objects
which are then flooded to adjacent repositories. A mirror receives
flooded transactions from remote repositories but is not the authori-
tative source for any objects. From a protocol standpoint, reposito-
ries and mirrors appear identical in the flooding topology.
Either a repository or a mirror may recheck all or a subset of trans-
actions that are flooded to it. A repository or mirror may elect not
to recheck authorization and authentication on transactions received
from a trusted adjacency on the grounds that the adjacent repository
is trusted and would not have flooded the information unless autho-
rization and authentication checks had been made.
If it can be arranged that all adjacencies are trusted for a given
mirror, then there is no need to implement the code to check autho-
rization and authentication. There is only a need to be able to check
the signatures on the flooded transactions of the adjacent reposito-
ry. This is an important special case because it could allow a router
to act as a mirror. Only changes to the registry database would be
received through flooding, which is a very low volume. Only the sig-
nature of the adjacent mirror or repository would have to be checked.
2 Data Representation
RPSL provides a complete description of the contents of a routing
repository [1]. Many RPSL data objects remain unchanged from the
RIPE, and RPSL references the RIPE-181 specification as recorded in
RFC-1786 [2]. RPSL provides external data representation. Data may
be stored differently internal to a routing registry. The integrity
of the distributed registry data requires the use of the authorization
and authentication additions to RPSL described in [3].
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Some additions to RPSL are needed to locate all of the repositories
after having located one of them and to make certain parameters se-
lectable on a per repository basis readily available. These additions
are described in Section 5.
Some form of encapsulation must be used to exchange data. The de-
facto encapsulation has been that which the RIPE tools accept, a plain
text file or plain text in the body of an RFC-822 formatted mail mes-
sage with information needed for authentication derived from the mail
headers. Merit has slightly modified this using the PGP signed por-
tion of a plain text file or PGP signed portion of the body of a mail
message.
The exchange that occurs during flooding differs from the initial
submission. In order to repeat the authorization checks the state
of all repositories containing objects referenced by the authoriza-
tion checks needs to be known. To accomplish this a sequence number
is associated with each transaction in a repository and the flooded
transactions must contain the sequence number of each repository on
which authorization of the transaction depends.
In order to repeat authorization checks it must be possible to re-
trieve back revisions of objects. How this is accomplished is a mat-
ter local to the implementation. One method which is quite simple is
to keep the traversal data structures to all current objects even if
the state is deleted, keep the sequence number that the version of the
object became effective and keep back links to prior versions of the
objects. Finding a prior version of an object involves looking back
through the references until the sequence number of the version of
the object is less than or equal to the sequence number being searched
for.
The existing very simple forms of encapsulation are adequate for the
initial submission of a database transaction and should be retained
as long as needed for backward compatibility. A more robust encapsu-
lation and submission protocol, with optional confirmation is defined
in Section 6.1. An encapsulation suitable for exchange of transaction
between repositories is addressed in Section 6. Query encapsulation
and protocol is outside the scope of this document.
3 Authentication and Authorization
Control must be exercised over who can make changes and what changes
they can make. The distinction of who vs what separates authentica-
tion from authorization.
o Authentication is the means to determine who is attempting to make
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a change.
o Authorization is the determination of whether a transaction pass-
ing a specific authentication check is allowed to perform a given
operation.
A submitted transaction contains a claimed identity. Depending on the
type of transaction, the authorization will depend on related objects.
The ``mnt-by'', ``mnt-routes'', or ``mnt-lower'' attributes in those
related objects reference ``maintainer'' objects. Those maintainer
objects contain ``auth'' attributes. The auth attributes contain an
authorization method and data which generally contains the claimed
identity and some form of public encryption key used to authenticate
the claim.
Authentication is done on transactions. Authentication should also be
done between repositories to insure the integrity of the information
exchange. In order to comply with import, export, and use restric-
tions throughout the world no encryption capability is specified.
Transactions must not be encrypted because it may be illegal to use
decryption software in some parts of the world.
4 Repository Hierarchy
With multiple repositories, ``repository'' objects are needed to prop-
agate the existence of new repositories and provide an automated means
to determine the supported methods of access and other characteristics
of the repository. The repository object is described in Section 5.
In each repository there should be a special repository object named
ROOT. This should point to the root repository or to a higher lev-
el repository. This is to allow queries to be directed to the local
repository but refer to the full set of registries for resolution of
hierarchically allocated objects.
Each repository may have an ``expire'' attribute. The expire at-
tribute is used to determine if a repository must be updated before a
local transaction that depends on it can proceed.
The repository object also contains attributes describing the access
methods and supported authentication methods of the repository. The
``query-address'' attribute provides a host name and a port number
used to direct queries. The ``response-auth-type'' attribute provides
the authentication types that may be used by the repository when re-
sponding to queries. The ``submit-address'' attribute provides a host
name and a port number used to submit objects to the repository. The
``submit-auth-type'' attribute provides the authentication types that
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may be used by the repository when responding to submissions.
5 Additions to RPSL
There are very few additions to RPSL defined here. The additions to
RPSL are referred to as RPSL ``objects''. They reside in the repos-
itory database and can be retrieved with ordinary queries. Objects
consist of ``attributes'', which are name/value pairs. Attributes
may be mandatory or optional. They may be single or multiple. One or
more attributes may be part of a key field. Some attributes may have
the requirement of being unique.
Most of the data formats described in this document are encapsula-
tions used in transaction exchanges. These are referred to as ``meta-
objects''. These ``meta-objects'', unlike RPSL ``objects'' do not
reside in the database but some must be retained in a transaction log.
A similar format is used to represent ``meta-objects''. They also
consist of ``attributes'' which are name/value pairs.
This section contains all of the additions to RPSL described in this
document. This section describes only RPSL objects. Other sections
described only meta-objects.
5.1 repository object
A root repository must be agreed upon. Ideally such a repository
would contain only top level delegations and pointers to other repos-
itories used in these delegations. It would be wise to allow only
cryptographically strong transactions in the root repository [3].
The root repository contains references to other repositories. An
object of the following form identifies another repository.
repository: RIPE
query-address: whois://whois.ripe.net
response-auth-type: PGPKEY-23F5CE35 # pointer to key-cert object
response-auth-type: none
remarks: you can request rsa signature on queries
remarks: PGP required on submissions
submit-address: mailto://auto-dbm@ripe.net
submit-address: rps-query://whois.ripe.net:43
submit-auth-type: pgp-key, crypt-pw, mail-from
remarks: these are the authentication types supported
mnt-by: maint-ripe-db
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expire: 0000 04:00:00
heartbeat-interval: 0000 01:00:00
...
remarks: admin and technical contact, etc
source: IANA
The attributes of the repository object are listed below.
repository key mandatory single
query-address mandatory multiple
response-auth-type mandatory multiple
submit-address mandatory multiple
submit-auth-type mandatory multiple
repository-cert mandatory multiple
expire mandatory single
heartbeat-interval mandatory single
descr optional multiple
remarks optional multiple
admin-c mandatory multiple
tech-c mandatory multiple
notify optional multiple
mnt-by mandatory multiple
changed mandatory multiple
source mandatory single
In the above object type only a small number of the attribute types
are new. These are:
repository This attribute provides the name of the repository. This
is the key field for the object and is single and must be globally
unique. This is the same name used in the source attribute of all
objects in that repository.
query-address This attribute provides a url for directing queries.
``rps-query'' or ``whois'' can be used as the protocol identifier.
response-auth-type This attribute provides an authentication type
that may be used by the repository when responding to user queries.
Its syntax and semantics is same as the auth attribute of the main-
tainer class.
submit-address This attribute provides a url for submitting objects
to the repository.
submit-auth-type This attribute provides the authentication types
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that are allowed by the repository for users when submitting regis-
trations.
repository-cert This attribute provides a reference to a public key
certificate in the form of an RPSL key-cert object. This attribute
can be multiple to allow the repository to use more than one method
of signature.
heartbeat-interval Heartbeat meta-objects are sent by this repos-
itory at the rate of one heartbeat meta-object per the interval
indicated. The value of this attribute shall be expressed in the
form ``dddd hh:mm:ss'', where the ``dddd'' represents days, ``hh''
represents hours, ``mm'' minutes and ``ss'' seconds.
expire If no heartbeat or new registrations are received from a
repository for expire period, objects from this repository should
be considered non-authoritative, and cannot be used for authoriza-
tion purposes. The value of this attribute shall be expressed in
the form ``dddd hh:mm:ss'', where the ``dddd'' represents days,
``hh'' represents hours, ``mm'' minutes and ``ss'' seconds. This
value should be bigger than heartbeat-interval.
Please note that the ``heartbeat'' meta-objects mentioned above, like
other meta-objects described in this document are part of the protocol
to exchange information but are not placed in the database itself.
See Section 7.3.2 for a description of the heartbeat meta-object.
The remaining attributes in the repository object are defined in RPSL.
5.2 delegated attribute
For many RPSL object types a particular entry should appear only in
one repository. These are the object types for which there is a natu-
ral hierarchy, ``as-block'', ``aut-num'', ``inetnum'', and ``route''.
In order to facilitate putting an object in another repository, a
``delegated'' attribute is added.
delegated The delegated attribute is allowed in any object type with
a hierarchy. This attribute indicates that further searches for
object in the hierarchy must be made in one or more alternate
repositories. The current repository may be listed. The ability
to list more than one repository serves only to accommodate grand-
fathered objects (those created prior to using an authorization
model). The value of a delegated attribute is a list of repository
names.
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If an object contains a ``delegated'' attribute, an exact key field
match of the object may also be contained in each repository listed in
the ``delegated'' attribute. For the purpose of authorizing changes
only the ``mnt-by'' in the object in the repository being modified is
considered.
The following is an example of the use of a ``delegated'' attribute.
inetnum: 193.0.0.0 - 193.0.0.255
delegated: RIPE
...
source: IANA
This inetnum simply delegates the storage of any more specific inetnum
objects overlapping the stated range to the RIPE repository. An exact
match of this inetnum may also exist in the RIPE repository to pro-
vide hooks for the attributes referencing maintainer objects. In this
case, when adding objects to the RIPE repository, the ``mnt-lower'',
`mnt-routes'', and ``mnt-by'' fields in the IANA inetnum object will
not be considered, instead the values in the RIPE copy will be used.
5.3 integrity attribute
The ``integrity'' attribute can be contained in any RPSL object. It
is intended solely as a means to facilitate a transition period during
which some data has been moved from repositories prior to the use of a
strong authorization model and is therefore questionable, or when some
repositories are not properly checking authorization.
The ``integrity'' attribute may have the values ``legacy'', ``no-
auth'', ``auth-failed'', or ``authorized''. If absent, the integrity
is considered to be ``authorized''. The integrity values have the
following meanings:
legacy: This data existed prior to the use of an adequate authoriza-
tion model. The data is highly suspect.
no-auth: This data was added to a repository during an initial tran-
sition use of an authorization model but authorization depended
on other objects whose integrity was not ``authorized''. Such an
addition is being allowed during the transition but would be disal-
lowed later.
auth-failed: The authoritative repository is not checking autho-
rization. Had it been doing so, authorization would have failed.
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This attribute may be added by a repository that is mirroring be-
fore placing the object in its local storage, or can add this at-
tribute to an encapsulating meta-object used to further propagate
the transaction. If the failure to enforce authorization is in-
tentional and part of a transition (for example, issuing warnings
only), then the authoritative repository may add this attribute to
the encapsulating meta-object used to further propagate the trans-
action.
authorized: Authorization checks were passed. The maintainer con-
tained a ``referral-by'' attribute, a form of authentication deemed
adequate by the repository was used, and all objects that were
needed for authorization were objects whose integrity was ``autho-
rized''.
Normally once an object is added to a repository another object cannot
overwrite it unless authorized to do so by the maintainers referenced
by the ``mnt-by'' attributes in the object itself. If the integrity
attribute is anything but ``authorized'', an object can be overwritten
or deleted by any transaction that would have been a properly autho-
rized addition had the object of lesser integrity not existed.
During such a transition grandfathered data and data added without
proper authorization becomes advisory until a properly authorized
addition occurs. After transition additions of this type would no
longer be accepted. Those objects already added without proper autho-
rization would remain but would be marked as candidates for replace-
ment.
6 Interactions with a Repository or Mirror
This section presents an overview of the transaction distribution
mechanisms. The detailed format of the meta-objects for encapsulating
and distributing transactions, and the rules for processing meta-
objects are described in Section 7. There are a few different types
of interactions between routing repositories or mirrors.
Initial submission of transactions: Transactions may include addi-
tions, changes, and deletions. A transaction may operate on more
than one object and must be treated as an atomic operation. By
definition initial submission of transactions is not applicable
to a mirror. Initial submission of transactions is described in
Section 6.1.
Redistribution of Transactions: The primary purpose of the inter-
actions between registries is the redistribution of transactions.
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There are a number of ways to redistribute transactions. Transac-
tions can also be rescinded. This is discussed in Section 6.2.
Queries: Query interactions are outside the scope of this document.
Rescinding Transactions Although it is hoped that the feature is
never needed, it may be necessary to rescind transactions (Sec-
tion 6.3).
Transaction Commit and Confirmation: Repositories may optionally im-
plement a commit protocol and a completion indication that gives
the submitter of a transaction a response that indicates that a
transaction has been successful and will not be lost by a crash of
the local repository. A submitter may optionally request such a
confirmation. This is discussed in Section 6.4.
6.1 Initial Transaction Submission
The simplest form of transaction submission is an object or set of
objects submitted with RFC--822 email encapsulation. This form is
still supported for backwards compatibility. A preferred form al-
lows some meta-information to be included in the submission, such
as a preferred form of confirmation. Where either encapsulation is
used, the submitter will connect to a host and port specified in the
repository object. This allows immediate confirmation. If an email
interface similar to the interface provided by the existing RIPE code
is desired, then an external program can provide the email interface.
The encapsulation of a transaction submission and response is de-
scribed in detail in Section 7.
6.2 Redistribution of Transactions
Redistribution of transactions can be accomplished using one of:
1. A repository snapshot is a request for the complete contents of
a given repository. This is usually done when starting up a new
repository or mirror or when recovering from a disaster, such as a
disk crash.
2. A transaction sequence exchange is a request for a specific set of
transactions. Often the request is for the most recent sequence
number known to a mirror to the last transactions. This is used in
polling.
3. Transaction flooding is accomplished through a unicast adjacency.
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This section describes the operations somewhat qualitatively. Data
formats and state diagrams are provided in Section 7.
6.3 Rescinding Transactions
Rescinding a transaction requires manual intervention. The adminis-
trators of a repository may find it necessary to request that a spe-
cific set of transactions be removed. Database mirrors would have to
roll back the entire database to the first transaction being rescinded
and then roll forward the transaction log from that point forward.
Authorizations in other repositories may be affected.
There are many reasons for having to rescind a transaction whose cause
is outside the control of the operator of the repository. For exam-
ple, a disgruntled employee at a client of the repository may remove
all authorization from that clients database objects. There may be
opportunities for malicious entries in objects for which there is no
authorization hierarchy (See [3]). An example is the anonymous regis-
tration of falsified person objects or libelous or obscene person or
role objects. In addition, mistakes or program bugs are inevitable.
The most compelling reason to support a rescind is the possibility of
a security breach at the repository that results in theft of identity
of the repository and falsified transactions. The rescind feature is
one that needs to be included but the repositories hope to never need.
6.4 Transaction Commit and Confirmation
If a submission requires a strong confirmation of completion, or if
a higher degree of protection against false positive confirmation is
desired as a matter of repository policy, a commit may be performed.
A commit request is a request from the repository processing an ini-
tial transaction submission to another repository to confirm that
they have been able to advance the transaction sequence up to the se-
quence number immediately below the transaction in the request and are
willing to accept the transaction in the request as a further advance
in the sequence. This indicates that either the authorization was
rechecked by the responding repository and passed or that the respond-
ing repository trusts the requesting repository and has accepted the
transaction.
A commit request can be sent to more than one alternate repository.
One commit completion response is sufficient to respond to the sub-
mitter with a positive confirmation that the transaction has been com-
pleted. However, the repository or submitter may optionally require
more than one.
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7 Data Format Summaries, Transaction Encapsulation and Processing
RIPE-181 [2] and RPSL [1] data is represented externally as ASCII tex-
t. Objects consist of a set of attributes. Attributes are name/value
pairs. A single attribute is represented as a single line with the
name followed by a colon followed by whitespace characters (space,
tab, or line continuation) and followed by the value. Within a val-
ue all consecutive whitespace characters is equivalent to a single
space. Line continuation is supported by putting a white space or
'+' character to the beginning of the continuation lines. An object
is externally represented as a sequence of attributes. Objects are
separated by blank lines.
Protocol interactions between registries are activated by passing
``meta objects''. Meta objects are not part of RPSL but conform to
RPSL object representation. They serve mostly as delimiters to the
protocol messages or to carry the request for an operation.
7.1 Transaction Submit and Confirm
The de-facto method for submitting database changes has been via e-
mail. This method should be supported by an external application.
Merit has added the pgp-from authentication method to the RADB (re-
placed by ``pgpkey'' in [4]), where the mail headers are essentially
ignored and the body of the mail message must be PGP signed.
This specification defines a different encapsulation for transaction
submission. When submitting a group of objects to a repository, a
user MUST append to that group of objects, exactly one ``timestamp''
and one or more ``signature'' meta-objects, in that order.
The ``timestamp'' meta-object contains a single attribute:
timestamp This attribute is mandatory and single-valued. This at-
tribute specifies the time at which the user submits the transac-
tion to the repository. The format of this attribute is ``YYYYMMDD
hh:mm:ss [+/-]xx:yy'', where ``YYYY'' specifies the four digit
year, ``MM'' represents the month, ``DD'' the date, ``hh'' the
hour, ``mm'' the minutes, ``ss'' the seconds of the timestamp, and
``xx'' and ``yy'' represents the hours and minutes respectively
that that timestamp is ahead or behind UTC.
A repository may reject a transaction which does not include the
``timestamp'' meta-object. The timestamp object is used to prevent
replaying registrations. How this is actually used is a local matter.
For example, a repository can accept a transaction only if the value
of the timestamp attribute is greater than the timestamp attribute
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in the previous registration received from this user (maintainer), or
the repository may only accept transactions with timestamps within its
expire window.
Each ``signature'' meta-object contains a single attribute:
signature This attribute is mandatory and single-valued. This at-
tribute, a block of free text, contains the signature corresponding
to the authentication method used for the transaction. When the
authentication method is a cryptographic hash (as in PGP-based au-
thentication), the signature must include all text upto (but not
including) the last blank line before the first ``signature'' meta-
object.
A repository must reject a transaction that does not include any
``signature'' meta-object.
The group of objects submitted by the user, together with the ``times-
tamp'' and ``signature'' meta-objects, constitute the ``submitted
text'' of the transaction.
The protocol used for submitting a transaction, and for receiving con-
firmation of locally committed transactions, is not specified in this
document. This protocol may define additional encapsulations around
the submitted text. The rest of this section gives an example of one
such protocol. Implementations are free to choose another encapsula-
tion.
The meta-objects ``transaction-submit-begin'' and ``transaction-
submit-end'' delimit a transaction. A transaction is handled as an
atomic operation. If any part of the transaction fails none of the
changes take effect. For this reason a transaction can only operate
on a single database.
A socket connection is used to request queries or submit transactions.
An email interface may be provided by an external program that con-
nects to the socket. A socket connection must use the ``transaction-
submit-begin'' and ``transaction-submit-end'' delimiters but can re-
quest a legacy style confirmation. Multiple transactions may be sent
prior to the response for any single transaction. Transactions may
not complete in the order sent.
The ``transaction-submit-begin'' meta-object may contain the following
attributes.
transaction-submit-begin This attribute is mandatory and single. The
value of the attribute contains name of the database and an identi-
fier that must be unique over the course of the socket connection.
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response-auth-type This attribute is optional and multiple. The re-
mainder of the line specifies an authentication type that would
be acceptable in the response. This is used to request a response
cryptographically signed by the repository.
transaction-confirm-type This attribute is optional and single. A
confirmation type keyword must be provided. Keywords are ``none'',
``legacy'', ``normal'', ``commit''. The confirmation type can be
followed by the option ``verbose''.
The ``transaction-submit-end'' meta-object consists of a single at-
tribute by the same name. It must contain the same database name
and identifier as the corresponding ``transaction-submit-begin'' at-
tribute.
Unless the confirmation type is ``none'' a confirmation is sent. If
the confirmation type is ``legacy'', then an email message of the for-
m currently sent by the RIPE database code will be returned on the
socket (suitable for submission to the sendmail program).
A ``normal'' confirmation does not require completion of the commit
protocol. A ``commit'' confirmation does. A ``verbose'' confirmation
may contain additional detail.
A transaction confirmation is returned as a ``transaction-confirm''
meta-object. The ``transaction-confirm'' meta-object may have the
following attributes.
transaction-confirm This attribute is mandatory and single. It con-
tains the database name and identifier associated with the transac-
tion.
confirmed-operation This attribute is optional and multiple. It
contains one of the keywords ``add'', ``delete'' or ``modify'' fol-
lowed by the object type and key fields of the object operated on.
commit-status This attribute is mandatory and single. It contain-
s one of the keywords ``succeeded'', ``error'', or ``held''. The
``error'' keyword may be followed by an optional text string. The
``held'' keyword is returned when a repository containing a depen-
dent object for authorization has expired.
7.2 Redistribution of Transactions
In order to redistribute transactions, each repository maintains a
TCP connection with one or more other repositories. After locally
committing a submitted transaction, a repository assigns a sequence
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number to the transaction, signs and encapsulates the transaction, and
then sends one copy to each neighboring (or ``peer'') repository. In
turn, each repository authenticates the transaction (as described in
Section 7.6), may re-sign the transaction and redistributes the trans-
action to its neighbors. We use the term ``originating repository''
to distinguish the repository that redistributes a locally submitted
transaction.
This document also specifies two other methods for redistributing
transactions to other repositories: a database snapshot format used
for initializing a new registry, and a polling technique used by mir-
rors.
In this section, we first describe how a repository may encapsulate
the submitted text of a transaction. We then describe the proto-
col for flooding transactions or polling for transactions, and the
database snapshot contents and format.
7.3 Redistribution Protocol Description
The originating repository must first authenticate a submitted trans-
action using methods described in [3].
Before redistributing a transaction, the originating repository must
encapsulate the submitted text of the transaction with several meta-
objects, which are described below.
The originating repository must prepend the submitted text with exact-
ly one ``transaction-label'' meta-object. This meta-object contains
the following attributes:
transaction-label This attribute is mandatory and single. The value
of this attribute conforms to the syntax of an RPSL word, and rep-
resents a globally unique identifier for the database to which this
transaction is added.
sequence This attribute is mandatory and single. The value of this
attribute is an RPSL integer specifying the sequence number as-
signed by the originating repository to the transaction. Succes-
sive transactions distributed by the same originating repository
have successive sequence numbers. The first transaction originat-
ed by a registry is assigned a sequence number 1. Each repository
must use sequence numbers drawn from a range at least as large as
64 bit unsigned integers.
timestamp This attribute is mandatory and single-valued. This at-
tribute specifies the time at which the originating repository
encapsulates the submitted text. The format of this attribute is
``YYYYMMDD hh:mm:ss [+/-]xx:yy'', where ``YYYY'' specifies the four
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digit year, ``MM'' represents the month, ``DD'' the date, ``hh''
the hour, ``mm'' the minutes, ``ss'' the seconds of the timestamp,
and ``xx'' and ``yy'' represents the hours and minutes respectively
that that timestamp is ahead or behind UTC.
integrity This attribute is optional and single-valued. It may have
the values ``legacy'', ``no-auth'', ``auth-failed'', or ``autho-
rized''. If absent, the integrity is considered to be ``autho-
rized''.
The originating repository may append to the submitted text one or
more ``auth-dependency'' meta-objects. These meta-objects are used
to indicate which other repositories' objects were used by the o-
riginating registry to authenticate the submitted text. The ``auth-
dependency'' meta-object contains the following attributes:
auth-dependency This attribute mandatory and single-valued. It e-
quals a repository name from which an object is used to autho-
rize/authenticate this transaction.
sequence This attribute mandatory and single-valued. It equals the
transaction sequence number of the dependent repository known at
the originating repository at the time of processing this transac-
tion.
timestamp This attribute mandatory and single-valued. It equals
the timestamp of the dependent repository known at the originating
repository at the time of processing this transaction.
If the originating repository needs to modify submitted objects in a
way that the remote repositories can not re-create, it can append an
``override-objects'' meta-object followed by the modified versions of
these objects. An example modification can be auto assignment of NIC
handles. The ``override-objects'' meta-object contains the following
attributes:
override-objects A free text remark.
Other repositories may or may not honor override requests, or limit
the kinds of overrides they allow.
Following this, the originating repository must append exactly one
``repository-signature'' meta-object. The ``repository-signature''
meta-object contains the following attributes:
repository-signature This attribute is mandatory and single-valued.
It contains the name of the repository.
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integrity This attribute is optional and single-valued. It may have
the values ``legacy'', ``no-auth'', ``auth-failed'', or ``au-
thorized''. If absent, the value is same as the value in the
transaction-label. If a different value is used, the value here
takes precedence.
signature This attribute is mandatory and single-valued. This at-
tribute, a block of free text, contains the repository's sig-
nature corresponding to the authentication method used for the
transaction. When the authentication method is a cryptographic
hash (as in PGP-based authentication), the signature must include
all text upto (but not including) this attribute. That is, the
``repository-signature'' and ``integrity'' attributes of this ob-
ject are included.
A repository must reject a redistributed transaction that does not
include any ``repository-signature'' meta-object.
The transaction-label, the submitted text, the dependency objects,
the override-objects, the overriden objects, and the repository's
signature together constitute what we call the ``redistributed text''.
In preparation for redistributing the transaction to other reposito-
ries, the originating repository must perform the following protocol
encapsulation. This protocol encapsulation may involve transforming
the redistributed text according to one of the ``transfer-method''s
described below.
The transformed redistributed text is first prepended with exactly one
``transaction-begin'' meta-object. One newline character separates
this meta-object from the redistributed text. This meta-object has
the following attributes:
transaction-begin This attribute is mandatory and single. The val-
ue of this attribute is the length, in bytes, of the transformed
redistributed text.
transfer-method This attribute is optional and single-valued. Its
value is either ``gzip'', or ``plain''. The value of the attribute
describes the kind of text encoding that the repository has per-
formed on the redistributed text. If this attribute is not speci-
fied, its value is assumed to be ``plain''. An implementation must
be capable of encoding and decoding both of these types.
The ``transaction-begin'' meta-object and the transformed redistribut-
ed text constitute what we call the ``transmitted text''. The origi-
nating repository may distribute the transmitted text to one or more
peer repositories.
When a repository receives the transmitted text of a transaction,
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it must perform the following steps. After performing the following
steps, a transaction may be marked successful or failed.
1. It must decapsulate the ``transaction-begin'' meta-object, then de-
code the original redistributed text according to the value of the
transfer-method attribute specified in the ``transaction-begin''
meta-object.
2. It should then extract the "transaction-label" meta-object from the
transmitted text. If this transaction has already been processed,
or is currently being held, the repository must silently discard
this incarnation of the same transaction.
3. It should verify that the signature of the originating reposito-
ry matches the first ``repository-signature'' meta-object in the
redistributed text following the ``auth-dependency'' meta-objects.
4. If not all previous (i.e., those with a lower sequence number)
transactions from the same repository have been received or com-
pletely processed, the repository must ``hold'' this transaction.
5. It may check whether any subsequent ``repository-signature'' meta-
objects were appended by a trusted repository. If so, this in-
dicates that the trusted repository verified the transaction's
integrity and marked its conclusion in the integrity attribute of
this object. The repository may verify the trusted repositories
signature and also mark the transaction with the same integrity,
and skip the remaining steps.
6. It should verify the syntactic correctness of the transaction. An
implementation may allow configurable levels of syntactic confor-
mance with RPSL [1]. This enables RPSL extensions to be incremen-
tally deployed in the distributed registry scheme.
7. The repository must authorize and authenticate this transaction.
To do this, it may need to reference objects and transactions from
other repositories. If these objects are not available, the repos-
itory must ``hold'' this transaction as described in Section 7.6,
until it can be authorized and authenticated later. In order to
verify authorization/authentication of this transaction, the repos-
itory must not use an object from a repository not mentioned in an
``auth-dependency'' meta-obect. The repository should also only
use the latest objects (by rolling back to earlier versions if nec-
essary) which are within the transaction sequence numbers of the
``auth-dependency'' meta-objects.
A non-originating repository must redistribute a failed transaction in
order not to cause a gap in the sequence.
To the redistributed text of a transaction, a repository may append
another ``repository-signature'' meta-object. This indicates that the
repository has verified the transaction's integrity and marked it in
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the ``integrity'' attribute of this object. The signature covers the
new redistributed text from (and including) the transaction-label ob-
ject to this object's signature attribute (including the ``repository-
signature'' and ``integrity'' attributes of this object, but excluding
the ``signature'' attribute). The original redistributed text, to-
gether with the new ``repository-signature'' meta-object constitutes
the modified redistributed text.
To redistribute a successful or failed transaction, the repository
must encapsulate the (original or modified) redistributed text with
a ``transaction-begin'' object. This step is essentially the same as
that performed by the originating repository (except that the reposi-
tory is free to use a different ``transfer-method'' from the one that
was in the received transaction.
7.3.1 Explicitly Requesting Transactions
A repository may also explicitly request one or more transactions be-
longing to a specified originating repository. This is useful for
catching up after a repository has been off-line for a period of time.
It is also useful for mirrors which intermittently poll a repository
for recently received transactions.
To request a range of transactions from a peer, a repository must send
a ``transaction-request'' meta-object to the peer. A ``transaction-
request'' meta-object may contain the following attributes:
transaction-request This attribute is mandatory and single. It con-
tains the name of the database whose transactions are being re-
quested.
sequence-begin This attribute is optional and single. It contains
the sequence number of the first transaction being requested.
sequence-end This attribute is optional and single. It contains the
sequence number of the last transaction being requested.
Upon receiving a ``transaction-request'' object, a repository performs
the following actions. If the ``sequence-begin'' attribute is not
specified, the repository assumes the request first sequence number
to be 1. The last sequence number is the lesser of the value of the
``sequence-end'' attributed and the highest completed transaction in
the corresponding database. The repository then, in order, transmits
the requested range of transactions. Each transaction is prepared
exactly according to the rules for redistribution specified in Sec-
tion 7.3.
After transmitting all the transactions, the peer repository must
send a ``transaction-response'' meta-object. This meta-object has the
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following attributes:
transaction-response This attribute is mandatory and single. It
contains the name of the database whose transactions are were re-
quested.
sequence-begin This attribute is optional and mandatory. It con-
tains the value of the ``sequence-begin'' attribute in the original
request. It is omitted if the corresponding attribute was not
specified in the original request.
sequence-end This attribute is optional and mandatory. It contains
the value of the ``sequence-end attribute in the original request.
It is omitted if the corresponding attribute was not specified in
the original request.
After receiving a ``transaction-response'' meta-object, a repository
may tear down the TCP connection to its peer. This is useful for mir-
rors that intermittently resynchronize transactions with a repository.
If the TCP connection stays open, repositories exchange subsequent
transactions according to the redistribution mechanism specified in
Section 7.3.
7.3.2 Heartbeat Processing
Each repository that has originated at least one transaction must pe-
riodically send a ``heartbeat'' meta-object. The interval between two
successive transmissions of this meta-object is configurable but must
be less than 1 day. This meta-object serves to indicate the liveness
of a particular repository. The repository liveness determines how
long transactions are held (See Section 7.6).
The ``heartbeat'' meta-object contains the following attributes:
heartbeat This attribute is mandatory and single. It contains the
name of the repository which originates this meta-object.
sequence This attribute is mandatory and single. It contains the
highest transaction sequence number that has been assigned by the
repository.
timestamp This attribute is mandatory and single. It contains the
time at which this meta-object was generated. The format of this
attribute is ``YYYYMMDD hh:mm:ss [+/-]xx:yy'', where ``YYYY'' spec-
ifies the four digit year, ``MM'' represents the month, ``DD'' the
date, ``hh'' the hour, ``mm'' the minutes, ``ss'' the seconds of
the timestamp, and ``xx'' and ``yy'' represents the hours and min-
utes respectively that that timestamp is ahead or behind UTC.
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Upon receiving a heartbeat meta-object, a repository must first check
the timestamp of the latest previously received heartbeat message.
If that timestamp exceeds the timestamp in the received heartbeat
message, the repository must silently discard the heartbeat message.
Otherwise, it must record the timestamp and sequence number in the
heartbeat message, and redistribute the heartbeat message, without
modification, to each of its peer repositories.
If the heartbeat message is from a repository previously unknown to
the recipient, the recipient may send a ``transaction-request'' to
one or more of its peers to obtain all transactions belonging to the
corresponding database. If the heartbeat message contains a sequence
number higher than the highest sequence number processed by the recip-
ient, the recipient may send a ``transaction-request'' to one or more
of its peers to obtain all transactions belonging to the corresponding
database.
7.4 Transaction Commit
Submitters may require stronger confirmation of commit for their
transactions (Section 6.4). This section describes a simple request-
response protocol by which a repository may provide this stronger
confirmation, by verifying if one or more other repositories have
committed the transaction. Implementation of this request-response
protocol is optional.
After it has redistributed a transaction, the originating repository
may request a commit confirmation from one or more peer repositories
by sending to them a ``commit-request'' meta-object. The ``commit-
request'' contains two attributes:
commit-request This attribute is mandatory and single. It contains
the name of the database for whom a commit confirmation is being
requested.
sequence This attribute is mandatory and single. It contains the
transaction sequence number for which a commit confirmation is be-
ing requested.
A repository that receives a ``commit-request'' must not redistribute
the request. It must delay the response until the corresponding
transaction has been processed. For this reason, the repository must
keep state about pending commit requests. It should discard this s-
tate if the connection to the requester is lost before the response
is sent. In that event, it is the responsibility of the requester to
resend the request.
Once a transaction has been processed (Section 7.3), a repository must
check to see if there exists any pending commit request for the trans-
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action. If so, it must send a ``commit-response'' meta-object to the
requester. This meta-object has three attributes:
commit-response This attribute is mandatory and single. It contains
the name of the database for whom a commit response is being sent.
sequence This attribute is mandatory and single. It contains the
transaction sequence number for which a commit response is being
sent.
commit-status This attribute is mandatory and single. It contain-
s one of the keywords ``held'', ``error'', or ``succeeded''. The
``error'' keyword may be followed by an optional text string. The
``held'' keyword is returned when a repository containing a depen-
dent object for authorization has expired.
7.5 Database Snapshot
A database snapshot provides a complete copy of a database. It is
intended only for repository initialization or disaster recovery. A
database snapshot is an out of band mechanism. A set of files are
created periodically at the source repository. These files are then
transferred to the requestor out of band (e.g. ftp transfer). The
objects in these files are then registered locally.
A snapshot of repository X contains the following set of files:
X.db This file contains the RPSL objects of repository X, separated
by blank lines. In addition to the RPSL objects and blank lines,
comment lines can be present. Comment lines start with the charac-
ter '#'. The comment lines are ignored. The file X.db ends in a
special comment line ``# eof''.
X.<class>.db This optional file if present contains the RPSL objects
in X.db that are of class <class>. The format of the file is same
as that of X.db.
X.transaction-label This file contains a transaction-label object
that records the timestamp and the latest sequence number of the
repository at the time of the snapshot.
Each of these files can be optionally compressed uzing gzip. This
is signified by appending the suffix .gz to the file name. Each of
these files can optionally be PGP signed. In this case, the detached
signature is stored in a file whose name is constructed by appending
.sig to the file name of the file being signed.
In order to construct a repository's contents from a snapshot, a
repository downloads these files. After uncompressing and checking
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signatures, the repository records these objects in its database.
No RPS authorization/authentication is done on these objects. The
transaction-label object provides the seed for the replication pro-
tocol to receive the follow on transactions from this repository.
Hence, it is not crucial to download an up to the minute snapshot.
After successfully playing a snapshot, it is possible that a repos-
itory may receive a transaction from a third repository that has a
dependency on an earlier version of one of the objects in the snap-
shot. This can only happen within the expire period of the repository
being downloaded, plus any possible network partition period. This
dependency is only important if the repository wants to re-verify RPS
authorization/authentication. There are three allowed alternatives
in this case. The simplest alternative is for the repository to ac-
cept the transaction and mark it with integrity ``no-auth''. The
second choice is to only peer with trusted repositories during this
time period, and accept the transaction with the same integrity as the
trusted repository (possibly as ``authorized''). The most preferred
alternative is not to download an up to the minute snapshot, but to
download an older snapshot, at minimum twice the repositories expire
time, in practice few days older. Upon replaying an older snapshot,
the replication protocol will fetch the more current transactions
from this repository. Together they provide the necessary versions of
objects to re-verify rps authorization/authentication.
7.6 Authenticating Operations
The ``signature'' and ``repository-signature'' meta-objects represent
detached signatures. Where multiple of these objects are present,
the signatures should be over the original contents, not over oth-
er detached signatures. This allows signatures to be checked in any
order.
A maintainer can also sign a transaction using several authentication
methods (some of which may be available in some repositories only).
In the case of PGP, the attributes of the ``signature'' and
``repository-signature'' meta-objects are the attributes contained
in a detached signature file produced by PGP.
Note that the RPSL objects themselves are not signed but the entire
transaction body is signed. When exchanging transactions among reg-
istries, the meta-objects (e.g. ``auth-dependency'') prior to the
first ``repository-signature'' meta object in the redistributed text
are also signed over.
Transactions must remain intact, including the signatures, even if
an authentication method provided by the submitter is not used by
a repository handling the message. An originating repository may
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chose to remove clear text passwords signatures from a transaction,
and replace it with the keyword ``clear-text-passwd'' followed by the
maintainer's id.
signature: clear-text-passwd <maintainer-name>
Note that this does not make the system less secure since clear text
password is an indication of total trust to the originating repository
by the maintainer.
A repository may sign a transaction that it verified. If at any point
the signature of a trusted repository is encountered, no further au-
thorization or authentication is needed.
7.7 Rescinding Transactions
To rescind a transaction, a new transaction whose submitted text con-
tains one ``rescind-request'', one timestamp and one signature objects
is sent. The signature should be generated using the repository key.
The ``rescind-request'' object contains the following attributes:
rescind-request This attribute is mandatory and single. It contains
the name of the database for whom a rescind request is being sent.
sequence This attribute is mandatory and single. It contains the
transaction sequence number for which a rescind request is being
sent.
Processing ``rescind-request'' requires out of band confirmation of
the request, hence operator intervention at the receiving end is re-
quired.
A Examples
RPSL provides an external representation of RPSL objects and at-
tributes. An attribute is a name/value pair. RPSL is line orient-
ed. Line continuation is supported, however most attributes fit on
a single line. The attribute name is followed by a colon, then any
amount of whitespace, then the attribute value. An example of the
ASCII representation of an RPSL attribute is the following:
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route: 140.222.0.0/16
An RPSL object is a set of attributes. Objects are separated from
each other by one or more blank lines. An example of a complete RPSL
object follows:
route: 140.222.0.0/16
descr: ANS Communications
origin: AS1673
member-of: RS-ANSOSPFAGGREGATE
mnt-by: ANS
changed: tck@ans.net 19980115
source: ANS
A.1 Initial Object Submission and Redistribution
Figure 1 outlines the steps involved in submitting an object and the
initial redistribution from the authoritative registry to its flooding
peers.
If the authorization check requires objects from other repositories,
then the sequence numbers of the local copies of those databases is
required for mirrors to recheck the authorization.
To simply resubmit the object from the prior example, the submitter
or a client application program acting on the submitter's behalf must
submit a transaction. The legacy method was to send PGP signed email.
The preferred method is for an interactive program to encapsulate a
request between ``transaction-submit-begin'' and ``transaction-submit-
end'' meta-objects and encapsulate that as a signed block as in the
following example:
transaction-submit-begin: ANS 1
response-auth-type: PGP
transaction-confirm-type: normal
route: 140.222.0.0/16
descr: ANS Communications
origin: AS1673
member-of: RS-ANSOSPFAGGREGATE
mnt-by: ANS
changed: curtis@ans.net 19990401
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+--------------+
| Transaction |
| signed by |
| submitter |
+--------------+
|
| 1
v
+---------------------+ 2
| Primary repository |---->+----------+
| identified by | | database |
| RPSL source |<----+----------+
+---------------------+ 3
|
| 4
v
+----------------+
| Redistributed |
| transaction |
+----------------+
1. submit object
2. authorization check
3. sequence needed for authorization
4. redistribute
Figure 1: Initial Object Submission and Redistribution
source: ANS
timestamp: 19990401 103000 +08:00
signature:
+ -----BEGIN PGP SIGNATURE-----
+ Version: PGP for Personal Privacy 5.0
+ MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
+
+ iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
+ Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
+ Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
+ PGBIEN3/NlM=
+ =c93c
+ -----END PGP SIGNATURE-----
transaction-submit-end: ANS 1
The signature covers the everything after the first blank line after
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the ``transaction-submit-begin'' object to the last blank line before
the ``signature'' meta-object. If multiple signatures are needed, it
would be quite easy to email this block and ask the other party to add
a signature-block and return or submit the transaction. Because of
delay in obtaining multiple signatures the accuracy of the ``times-
tamp'' cannot be strictly enforced. Enforcing accuracy to within the
``expire'' time of the database might be a reasonable compromise. The
tradeoff is between convenience, allowing a longer time to obtain
multiple signatures, and increased time of exposure to replay attack.
The ANS repository would look at its local database and make autho-
rization checks. If the authorization passes, then the sequence num-
ber of any other database needed for the authorization is obtained.
If this operation was successful, then a confirmation would be re-
turned. The confirmation would be of the form:
transaction-confirm: ANS 1
confirmed-operation: change route 140.222.0.0/16 AS1673
commit-status: commit
timestamp: 19990401 103010 +05:00
A.2 Transaction Redistribution Encoding
Having passed the authorization check the transaction is given a se-
quence number and stored in the local transaction log and is then
flooded. The meta-object flooded to another database would be signed
by the repository and would be of the following form:
transaction-label: ANS
sequence: 6666
timestamp: 19990401 133010 +05:00
integrity: authorized
route: 140.222.0.0/16
descr: ANS Communications
origin: AS1673
member-of: RS-ANSOSPFAGGREGATE
mnt-by: ANS
changed: curtis@ans.net 19990401
source: ANS
timestamp: 19990401 103000 +08:00
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signature:
+ -----BEGIN PGP SIGNATURE-----
+ Version: PGP for Personal Privacy 5.0
+ MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
+
+ iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
+ Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
+ Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
+ PGBIEN3/NlM=
+ =c93c
+ -----END PGP SIGNATURE-----
auth-dependency: ARIN
sequence: 555
timestamp: 19990401 133008 +05:00
auth-dependency: RADB
sequence: 4567
timestamp: 19990401 132754 +05:00
repository-signature: ANS
signature:
+ -----BEGIN PGP SIGNATURE-----
+ Version: PGP for Personal Privacy 5.0
+ MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
+
+ iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
+ Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
+ Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
+ PGBIEN3/NlM=
+ =c93c
+ -----END PGP SIGNATURE-----
Note that the repository-signature above is a detached signature for
another file and is illustrative only. The repository-signature cov-
ers from the ``transaction-label'' meta-object (including) to the last
blank line before the first ``repository-signature'' meta-object (ex-
cluding the last blank line and the ``repository-signature'' object).
A.3 Transaction Protocol Encoding
transaction-begin: 1276
transfer-method: plain
transaction-label: ANS
sequence: 6666
timestamp: 19990401 133010 +05:00
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integrity: authorized
route: 140.222.0.0/16
descr: ANS Communications
origin: AS1673
member-of: RS-ANSOSPFAGGREGATE
mnt-by: ANS
changed: curtis@ans.net 19990401
source: ANS
timestamp: 19990401 103000 +08:00
signature:
+ -----BEGIN PGP SIGNATURE-----
+ Version: PGP for Personal Privacy 5.0
+ MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
+
+ iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
+ Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
+ Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
+ PGBIEN3/NlM=
+ =c93c
+ -----END PGP SIGNATURE-----
auth-dependency: ARIN
sequence: 555
timestamp: 19990401 133008 +05:00
auth-dependency: RADB
sequence: 4567
timestamp: 19990401 132754 +05:00
repository-signature: ANS
signature:
+ -----BEGIN PGP SIGNATURE-----
+ Version: PGP for Personal Privacy 5.0
+ MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
+
+ iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
+ Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
+ Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
+ PGBIEN3/NlM=
+ =c93c
+ -----END PGP SIGNATURE-----
Before the transaction is sent to a peer, the repository prepends a
``transaction-begin'' meta-object. The value of the ``transaction-
begin'' attribute is the number of octets in the transaction, not
counting the ``transaction-begin'' meta-object and the first blank
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Internet Draft Routing Policy System Replication August 31, 1999
line after it.
Separating transaction-begin and transaction-label objects enables
different encodings at different flooding peerings.
A.4 Transaction Redistribution
The last step in Figure 1 was redistributing the submitter's trans-
action through flooding (or later through polling). Figure 2 illus-
trates the further redistribution of the transaction.
+----------------+
| Redistributed |
| transaction |
+----------------+
|
| 1
v
+--------------------+ 2
| |---->+----------+
| Mirror repository | | database |
| |<----+----------+
+--------------------+ 3
|
| 4
v
+------------------+
|+----------------+|
|| Redistributed ||
|| transaction ||
|+----------------+|
| Optional |
| signature |
+------------------+
1. redistribute transaction
2. recheck authorization against full DB at the
time of the transaction using sequence numbers
3. authorization pass/fail
4. optionally sign then redistribute
Figure 2: Further Transaction Redistribution
If the authorization check was repeated, the mirror may optionally add
a repository-signature before passing the transaction any further. A
``signature'' can be added within that block. The previous signatures
should not be signed.
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Figure 3 illustrates the special case referred to as a ``lightweight
mirror''. This is specifically intended for routers.
+----------------+
| Redistributed |
| transaction |
+----------------+
| 1
v
+--------------------+ 2
| |---->+----------+
| Mirror repository | | database |
| |<----+----------+
+--------------------+ 3
| 4
v
+----------------+
| Redistributed |
| transaction |
+----------------+
| 5
v
+--------------------+
| Lightweight | 6 +----------+
| Mirror repository |---->| database |
| (router?) | +----------+
+--------------------+
1. redistribute transaction
2. recheck authorization against full DB at the
time of the transaction using sequence numbers
3. authorization pass/fail
4. sign and redistribute
5. just check mirror signature
6. apply change with no authorization check
Figure 3: Redistribution to Lightweight Mirrors
The lightweight mirror must trust the mirror from which it gets a
feed. This is a safe assumption if the two are under the same admin-
istration (the mirror providing the feed is a host owned by the same
ISP who owns the routers). The lightweight mirror simply checks the
signature of the adjacent repository to insure data integrity.
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B Technical Discussion
B.1 Server Processing
This document does not mandate any particular software design, pro-
gramming language choice, or underlying database or underlying operat-
ing system. Examples are given solely for illustrative purposes.
B.1.1 getting connected
There are two primary methods of communicating with a repository serv-
er. E-mail can be sent to the server. This method may be deprecated
but at least needs to be supported during transition. The second
method is preferred, connect directly to a TCP socket.
Traditionally the whois service is supported for simple queries. It
might be wise to retain the whois port connection solely for simple
queries and use a second port not in the reserved number space for
all other operations including queries except those queries using the
whois unstructured single line query format.
There are two styles of handling connection initiation is the dedi-
cated daemon, in the style of BSD sendmail, or launching through a
general purpose daemon such as BSD inetd. E-mail is normally handled
sequentially and can be handled by a front end program which will make
the connection to a socket in the process as acting as a mail delivery
agent.
B.1.2 rolling transaction logs forward and back
There is a need to be able to easily look back at previous states of
any database in order to repeat authorization checks at the time of
a transaction. This is difficult to do with the RIPE database imple-
mentation, which uses a sequentially written ASCII file and a set of
Berkeley DB maintained index files for traversal. At the very min-
imum, the way in which deletes or replacements are implemented would
need to be altered.
In order to easily support a view back at prior versions of object-
s, the sequence number of the transaction at which each object was
entered would need to be kept with the object. A pointer would be
needed back to the previous state of the object. A deletion would
need to be implemented as a new object with a deleted attribute, re-
placing the previous version of the object but retaining a pointer
back to it.
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A separate transaction log needs to be maintained. Beyond some age,
the older versions of objects and the the older transaction log en-
tries can be removed although it is probably wise to archive them.
B.1.3 committing or disposing of transactions
The ability to commit large transaction, or reject them as a whole
poses problems for simplistic database designs. This form of commit
operation can be supported quite easily using memory mapped files.
The changes can be made in virtual memory only and then either commit-
ted or disposed of.
B.1.4 dealing with concurrency
Multiple connections may be active. In addition, a single connection
may have multiple outstanding operations. It makes sense to have a
single process or thread coordinate the responses for a given connec-
tion and have multiple processes or threads each tending to a single
operation. The operations may complete in random order.
Locking on reads is not essential. Locking before write access is es-
sential. The simplest approach to locking is to lock at the database
granularity or at the database and object type granularity. Finer
locking granularity can also be implemented. Because there are mul-
tiple databases, deadlock avoidance must be considered. The usual
deadlock avoidance mechanism is to acquire all necessary locks in a
single operation or acquire locks in a prescribed order.
B.2 Repository Mirroring for Redundancy
There are numerous reasons why the operator of a repository might
mirror their own repository. Possibly the most obvious are redundan-
cy and the relative ease of disaster recovery. Another reason might
be the widespread use of a small number of implementations (but more
than one) and the desire to insure that the major repository soft-
ware releases will accept a transaction before fully committing to the
transaction. This may avoid the need to rescind transactions in the
face of a newly discovered bug.
The operation of a repository mirror used for redundancy is quite s-
traightforward. The transactions of the primary repository host can
be immediately fed to the redundant repository host. For tighter as-
surances that false positive confirmations will be sent, as a matter
of policy the primary repository host can require commit confirmation
before making a transaction sequence publicly available.
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There are many ways in which the integrity of local data can be as-
sured regardless of a local crash in the midst of transaction disk
writes. For example, transactions can be implemented as memory mapped
file operations, with disk synchronization used as the local commit
mechanism, and disposal of memory copies of pages used to handle com-
mit failures. The old pages can be written to a separate file, the
new pages written into the database. The transaction can be logged
and old pages file can then be removed. In the event of a crash, the
existence of a old pages file and the lack of a record of the transac-
tion completing would trigger a transaction roll back by writing the
old pages back to the database file.
The primary repository host can still sustain severe damage such as a
disk crash. If the primary repository host becomes corrupted, the use
of a mirror repository host provides a backup and can provide a rapid
recovery from disaster by simply reversing roles.
If a mirror is set up using a different software implementation with
commit mirror confirmation required, any transaction which fails due a
software bug will be deferred indefinitely allowing other transactions
to proceed rather than halting the remote processing of all transac-
tions until the bug is fixed everywhere or the offending transaction
is rescinded.
B.3 Trust Relationships
If all repositories trust each other then there is never a need to
repeat authorization checks. This enables a convenient interim step
for deployment prior to the completion of software supporting that
capability. The opposite case is where no repository trusts any other
repository. In this case, all repositories must roll forward trans-
actions gradually, checking the authorization of each remote transac-
tion.
It is likely that repositories will trust a subset of other reposi-
tories. This trust can reduce the amount of processing a repository
required to maintain mirror images of the full set of data. For exam-
ple, a subset of repositories might be trustworthy in that they take
reasonable security measures, the organizations themselves have the
integrity not to alter data, and these repositories trust only a lim-
ited set of similar repositories. If any one of these repositories
receives a transaction sequence and repeats the authorization checks,
other major repositories which trusts that repository need not re-
peat the checks. In addition, trust need not be mutual to reap some
benefit in reduced processing.
As a transaction sequence is passed from repository to repository each
repository signs the transaction sequence before forwarding it. If
a receiving repository finds that any trusted repository has signed
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the transaction sequence it can be considered authorized since the
trusted repository either trusted a preceding repository or repeated
the authorization checks.
B.4 A Router as a Minimal Mirror
A router could serve as a minimal repository mirror. The following
simplifications can be made.
1. No support for repeating authorization checks or transaction au-
thentication checks need be coded in the router.
2. The router must be adjacent only to trusted mirrors, generally op-
erated by the same organization.
3. The router would only check the authentication of the adjacent
repository mirrors.
4. No support for transaction submission or query need be coded in the
router. No commit support is needed.
5. The router can dispose of any object types or attributes not needed
for configuration of route filters.
The need to update router configurations could be significantly re-
duced if the router were capable of acting as a limited repository
mirror.
A significant amount of non-volatile storage would be needed. There
are currently an estimated 100 transactions per day. If storage were
flash memory with a limited number of writes, or if there were some
other reason to avoid writing to flash, the router could only update
the non-volatile copy every few days. A transaction sequence request
can be made to get an update in the event of a crash, returning only a
few hundred updates after losing a few days of deferred writes. The
routers can still take a frequent or continuous feed of transactions.
Alternately, router filters can be reconfigured periodically as they
are today.
B.5 Dealing with Errors
If verification of an authorization check fails, the entire trans-
action must be rejected and no further advancement of the repository
can occur until the originating repository corrects the problem. If
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the problem is due to a software bug, the offending transaction can
be removed manually once the problem is corrected. If a software bug
exists in the receiving software, then the transaction sequence is
stalled until the bug is corrected. It is better for software to er-
ror on the side of denying a transaction than acceptance, since an
error on the side of acceptance will require rescinding transactions
and rolling forward only those that were valid.
C Deployment Considerations
This section described deployment considerations. The intention is to
raise issues rather than to provide a deployment plan.
This document calls for a transaction exchange mechanism similar to
but not identical to the existing ``near real time mirroring'' sup-
ported by the code base widely used by the routing registries. As an
initial step, the transaction exchange can be implemented without the
commit protocol or the ability to recheck transaction authorization.
This is a fairly minimal step from the existing capabilities.
The transition can be staged as follows:
1. Modify the format of ``near real time mirroring'' transaction ex-
change to conform to the specifications of this document.
2. Implement commit protocol and confirmation support.
3. Implement remote recheck of authorization. Prior to this step all
repositories must be trusted.
4. Allow further decentralization of the repositories.
D Privacy of Contact Information
The routing registries have contained contact information. The redis-
tribution of this contact information has been a delicate issue and in
some countries has legal implications.
The person and role objects contain contact information. These ob-
jects are referenced by NIC-handles. There are some attributes such
as the "changed" and "notify" attributes that require an email ad-
dress. All of the fields that currently require an email address must
also accept a NIC-handle.
The person and role objects should not be redistributed by default.
If a submission contains an email address in a field such as a changed
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field rather than a NIC-handle the submitter should be aware that they
are allowing that email address to be redistributed and forfeiting any
privacy. Repositories which do not feel that prior warnings of this
forfeiture are sufficient legal protection should reject the submis-
sion requesting that a NIC-handle be used.
Queries to role and person objects arriving at a mirror must be re-
ferred to the authoritative repository where whatever authentication,
restrictions, or limitations deemed appropriate by that repository can
be enforced directly.
Software should make it possible to restrict the redistribution of
other entire object types as long as those object types are not re-
quired for the authorization of additions of other object types. It
is not possible to redistribute objects with attributes removed or
altered since this would invalidate the submitter's signature and make
subsequent authentication checks impossible. Repositories should not
redistribute a subset of the objects of a given type.
Software should also not let a transaction contain both redis-
tributable (e.g. policy objects) and non-redustributable objects
(e.g. person) since there is no way to verify the signature of these
transactions without the non-redustributable objects.
When redistributing legacy data, contact information in attributes
such as "changed" and "notify" should be stripped to maintain privacy.
The "integrity" attribute on these objects should already be set to
"legacy" indicating that their origin is questionable, so the issue of
not being able to recheck signatures is not as significant.
References
[1] C. Alaettinoglu, C. Villamizar, E. Gerich, D. Kessens, D. Meyer,
T. Bates, D. Karrenberg, and M. Terpstra. Routing Policy Spec-
ification Language (RPSL). Technical Report RFC 2622, Internet
Engineering Task Force, 1999.
[2] T. Bates, E. Gerich, L. Joncheray, J-M. Jouanigot, D. Karrenberg,
M. Terpstra, and J. Yu. Representation of IP Routing Policies
in a Routing Registry (ripe-81++). Technical Report RFC 1786,
Internet Engineering Task Force, 1995.
[3] David Meyer, Curtis Villamizar, Cengiz Alaettinoglu, and S. Mur-
phy. Routing Policy System Security. Internet Draft (Work in
Progress) draft-ietf-rps-auth-04, Internet Engineering Task
Force, 7 1999.
[4] Janos Zsako. PGP authentication for RIPE database updates. Inter-
net Draft (Work in Progress) draft-ietf-rps-dbsec-pgp-authent-01,
Internet Engineering Task Force, 4 1999.
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Internet Draft Routing Policy System Replication August 31, 1999
Security Considerations
An authentication and authorization model for routing policy object
submission is provided by [3]. Cryptographic authentication is ad-
dressed by [4]. This document provides a protocol for the exchange of
information among distributed routing registries such that the autho-
rization model provided by [3] can be adhered to by all registries and
any deviation (hopefully accidental) from those rules on the part of a
registry can be identified by other registries or mirrors.
Author's Addresses
Curtis Villamizar Cengiz Alaettinoglu
Avici Systems ISI
<curtis@avici.com> <cengiz@ISI.EDU>
Ramesh Govindan David M. Meyer
ISI Cisco
<govindan@ISI.EDU> <dmm@cisco.com>
Full Copyright Statement
Copyright (C) The Internet Society (August 31, 1999). All Rights
Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are in-
cluded on all such copies and derivative works. However, this doc-
ument itself may not be modified in any way, such as by removing the
copyright notice or references to the Internet Society or other In-
ternet organizations, except as needed for the purpose of developing
Internet standards in which case the procedures for copyrights defined
in the Internet Standards process must be followed, or as required to
translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
Villamizar,Alaettinoglu,Govindan,Meyer Expires March 1, 2000[Page 39]
Internet Draft Routing Policy System Replication August 31, 1999
``AS IS'' basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEER-
ING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUD-
ING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MER-
CHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Villamizar,Alaettinoglu,Govindan,Meyer Expires March 1, 2000[Page 40]
