Internet Architecture Board (IAB) P. Hoffman

Internet Architecture Board (IAB) P. Hoffman
Request for Comments: 7998 ICANN
Category: Informational J. Hildebrand
ISSN: 2070-1721 Mozilla
December 2016

"xml2rfc" Version 3 Preparation Tool Description

Abstract

This document describes some aspects of the "prep tool" that is
expected to be created when the new xml2rfc version 3 specification
is deployed.

Status of This Memo

This document is not an Internet Standards Track specification; it is
published for informational purposes.

This document is a product of the Internet Architecture Board (IAB)
and represents information that the IAB has deemed valuable to
provide for permanent record. It represents the consensus of the
Internet Architecture Board (IAB). Documents approved for
publication by the IAB are not a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7998.

Copyright Notice

Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.

Hoffman & Hildebrand Informational [Page 1]

RFC 7998 v3 Prep Tool December 2016

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. xml2rfc v3 Prep Tool Usage Scenarios . . . . . . . . . . . . 4
3. Internet-Draft Submission . . . . . . . . . . . . . . . . . . 4
4. Canonical RFC Preparation . . . . . . . . . . . . . . . . . . 5
5. What the v3 Prep Tool Does . . . . . . . . . . . . . . . . . 5
5.1. XML Sanitization . . . . . . . . . . . . . . . . . . . . 6
5.1.1. XInclude Processing . . . . . . . . . . . . . . . . . 6
5.1.2. DTD Removal . . . . . . . . . . . . . . . . . . . . . 6
5.1.3. Processing Instruction Removal . . . . . . . . . . . 6
5.1.4. Validity Check . . . . . . . . . . . . . . . . . . . 6
5.1.5. Check "anchor" . . . . . . . . . . . . . . . . . . . 6
5.2. Defaults . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2.1. "version" Insertion . . . . . . . . . . . . . . . . . 6
5.2.2. "seriesInfo" Insertion . . . . . . . . . . . . . . . 7
5.2.3. <date> Insertion . . . . . . . . . . . . . . . . . . 7
5.2.4. "prepTime" Insertion . . . . . . . . . . . . . . . . 7
5.2.5. <ol> Group "start" Insertion . . . . . . . . . . . . 7
5.2.6. Attribute Default Value Insertion . . . . . . . . . . 7
5.2.7. Section "toc" attribute . . . . . . . . . . . . . . . 7
5.2.8. "removeInRFC" Warning Paragraph . . . . . . . . . . . 8
5.3. Normalization . . . . . . . . . . . . . . . . . . . . . . 8
5.3.1. "month" Attribute . . . . . . . . . . . . . . . . . . 8
5.3.2. ASCII Attribute Processing . . . . . . . . . . . . . 8
5.3.3. "title" Conversion . . . . . . . . . . . . . . . . . 9
5.4. Generation . . . . . . . . . . . . . . . . . . . . . . . 9
5.4.1. "expiresDate" Insertion . . . . . . . . . . . . . . . 9
5.4.2. <boilerplate> Insertion . . . . . . . . . . . . . . . 9
5.4.2.1. Compare <rfc> "submissionType" and <seriesInfo>
"stream" . . . . . . . . . . . . . . . . . . . . 9
5.4.2.2. "Status of this Memo" Insertion . . . . . . . . . 9
5.4.2.3. "Copyright Notice" Insertion . . . . . . . . . . 10
5.4.3. <reference> "target" Insertion . . . . . . . . . . . 10
5.4.4. <name> Slugification . . . . . . . . . . . . . . . . 10
5.4.5. <reference> Sorting . . . . . . . . . . . . . . . . . 10
5.4.6. "pn" Numbering . . . . . . . . . . . . . . . . . . . 10
5.4.7. <iref> Numbering . . . . . . . . . . . . . . . . . . 11
5.4.8. <xref> Processing . . . . . . . . . . . . . . . . . . 11
5.4.8.1. "derivedContent" Insertion (with Content) . . . . 11
5.4.8.2. "derivedContent" Insertion (without Content) . . 11
5.4.9. <relref> Processing . . . . . . . . . . . . . . . . . 12
5.5. Inclusion . . . . . . . . . . . . . . . . . . . . . . . . 12
5.5.1. <artwork> Processing . . . . . . . . . . . . . . . . 12
5.5.2. <sourcecode> Processing . . . . . . . . . . . . . . . 14

Hoffman & Hildebrand Informational [Page 2]

RFC 7998 v3 Prep Tool December 2016

5.6. RFC Production Mode Cleanup . . . . . . . . . . . . . . . 14
5.6.1. <note> Removal . . . . . . . . . . . . . . . . . . . 14
5.6.2. <cref> Removal . . . . . . . . . . . . . . . . . . . 15
5.6.3. <link> Processing . . . . . . . . . . . . . . . . . . 15
5.6.4. XML Comment Removal . . . . . . . . . . . . . . . . . 15
5.6.5. "xml:base" and "originalSrc" Removal . . . . . . . . 15
5.6.6. Compliance Check . . . . . . . . . . . . . . . . . . 15
5.7. Finalization . . . . . . . . . . . . . . . . . . . . . . 15
5.7.1. "scripts" Insertion . . . . . . . . . . . . . . . . . 16
5.7.2. Pretty-Format . . . . . . . . . . . . . . . . . . . . 16
6. Additional Uses for the Prep Tool . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. Informative References . . . . . . . . . . . . . . . . . . . 17
IAB Members at the Time of Approval . . . . . . . . . . . . . . . 18
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18

1. Introduction

As initially described in [RFC6949], the canonical format (the data
that is the authorized, recognized, accepted, and archived version of
the document) of the RFC Series has been plain text to date: it is
now changing to XML (using the xml2rfc v3 vocabulary [RFC7991]).

However, most people will read RFCs in other formats, such as HTML,
PDF, ASCII text, or other formats not yet in existence. In order to
ensure as much uniformity in text output as possible across formats
(and with the canonical XML itself), there is a desire that the
translation from XML into the other formats will be straightforward
syntactic translation. To make that happen, a good amount of data
will need to be in the XML format that is not there today. That data
will be added by a program called the "prep tool", which will often
run as a part of the xml2rfc process.

This document specifies the steps that the prep tool will have to
take. When changes to the xml2rfc v3 vocabulary [RFC7991] are made,
this document is likely to be updated at the same time.

The details (particularly any vocabularies) described in this
document are expected to change based on experience gained in
implementing the new publication toolsets. Revised documents will be
published capturing those changes as the toolsets are completed.
Other implementers must not expect those changes to remain backwards-
compatible with the details described in this document.

Hoffman & Hildebrand Informational [Page 3]

RFC 7998 v3 Prep Tool December 2016

2. xml2rfc v3 Prep Tool Usage Scenarios

The prep tool will have several settings:

o Internet-Draft preparation

o Canonical RFC preparation

There are only a few differences between the two settings: for
example, the boilerplate output and the date output on the front
page.

Note that this document only describes what the IETF-sponsored prep
tool does. Others might create their own work-alike prep tools for
their own formatting needs. However, an output format developer does
not need to change the prep tool in order to create their own
formatter: they only need to be able to consume prepared text. The
IETF-sponsored prep tool runs in two different modes: "I-D" mode when
the tool is run during Internet-Draft submission and processing and
"RFC production mode" when the tool is run by the RFC Production
Center while producing an RFC.

This tool is described as if it is a separate tool so that we can
reason about its architectural properties. In actual implementation,
it might be a part of a larger suite of functionality.

3. Internet-Draft Submission

When the IETF draft submission tool accepts xml2rfc version 3
vocabulary [RFC7991] (referred to as "v3" hereafter) as an input
format, the submission tool runs the submitted file through the prep
tool. This is called "I-D mode" in this document. If the tool finds
no errors, it keeps two XML files: the submitted file and the prepped
file.

The prepped file provides a record of what a submitter was attesting
to at the time of submission. It represents a self-contained record
of what any external references resolved to at the time of
submission.

The prepped file is used by the IETF formatters to create outputs
such as HTML, PDF, and text (or the tools act in a way
indistinguishable from this). The message sent out by the draft
submission tool includes a link to the submitted XML as well as the
other outputs, including the prepped XML.

Hoffman & Hildebrand Informational [Page 4]

RFC 7998 v3 Prep Tool December 2016

The prepped XML can be used by tools not yet developed to output new
formats that have as similar output as possible to the current IETF
formatters. For example, if the IETF creates a .mobi output renderer
later, it can run that renderer on all of the prepped XML that has
been saved, ensuring that the content of included external references
and all of the part numbers and boilerplate will be the same as what
was produced by the previous IETF formatters at the time the document
was first uploaded.

4. Canonical RFC Preparation

During editing, the RPC will run the prep tool in canonical RFC
production mode and make the results available to the authors during
AUTH48 (see [PUB-PROCESS]) so they can see what the final output
would look like. When the document has passed AUTH48 review, the RPC
runs the prep tool in canonical RFC production mode one last time,
locks down the canonicalized XML, runs the formatters for the
publication formats, and publishes all of those.

This document assumes that the prep tool will be used by the RPC in
the manner described in this document; they may use something
different or with different configuration.

Similar to the case for I-Ds, the prepped XML can be used later to
re-render the output formats or to generate new formats.

5. What the v3 Prep Tool Does

The steps listed here are in order of processing. In all cases where
the prep tool would "add" an attribute or element, if that attribute
or element already exists, the prep tool will check that the
attribute or element has valid values. If the value is incorrect,
the prep tool will warn with the old and new values, then replace the
incorrect value with the new value.

Currently, the IETF uses a tool called "idnits" [IDNITS] to check
text input to the Internet-Drafts posting process. idnits indicates
if it encountered anything it considers an error and provides text
describing all of the warnings and errors in a human-readable form.
The prep tool should probably check for as many of these errors and
warnings as possible when it is processing the XML input. For the
moment, tooling might run idnits on the text output from the prepared
XML. The list below contains some of these errors and warnings, but
the deployed version of the prep tool may contain additional steps to
include more or the checks from idnits.

Hoffman & Hildebrand Informational [Page 5]

RFC 7998 v3 Prep Tool December 2016

5.1. XML Sanitization

These steps will ensure that the input document is properly formatted
and that all XML processing has been performed.

5.1.1. XInclude Processing

Process all <x:include> elements. Note: XML <x:include> elements may
include more <x:include> elements (with relative references resolved
against the base URI potentially modified by a previously inserted
xml:base attribute). The tool may be configurable with a limit on
the depth of recursion.

5.1.2. DTD Removal

Fully process any Document Type Definitions (DTDs) in the input
document, then remove the DTD. At a minimum, this entails processing
the entity references and includes for external files.

5.1.3. Processing Instruction Removal

Remove processing instructions.

5.1.4. Validity Check

Check the input against the RELAX NG (RNG) in [RFC7991]. If the
input is not valid, give an error.

5.1.5. Check "anchor"

Check all elements for "anchor" attributes. If any "anchor"
attribute begins with "s-", "f-", "t-", or "i-", give an error.

5.2. Defaults

These steps will ensure that all default values have been filled in
to the XML, in case the defaults change at a later date. Steps in
this section will not overwrite existing values in the input file.

5.2.1. "version" Insertion

If the <rfc> element has a "version" attribute with a value other
than "3", give an error. If the <rfc> element has no "version"
attribute, add one with the value "3".

Hoffman & Hildebrand Informational [Page 6]

RFC 7998 v3 Prep Tool December 2016

5.2.2. "seriesInfo" Insertion

If the <front> element of the <rfc> element does not already have a
<seriesInfo> element, add a <seriesInfo> element with the name
attribute based on the mode in which the prep tool is running
("Internet-Draft" for Draft mode and "RFC" for RFC production mode)
and a value that is the input filename minus any extension for
Internet-Drafts, and is a number specified by the RFC Editor for
RFCs.

5.2.3. <date> Insertion

If the <front> element in the <rfc> element does not contain a <date>
element, add it and fill in the "day", "month", and "year" attributes
from the current date. If the <front> element in the <rfc> element
has a <date> element with "day", "month", and "year" attributes, but
the date indicated is more than three days in the past or is in the
future, give a warning. If the <front> element in the <rfc> element
has a <date> element with some but not all of the "day", "month", and
"year" attributes, give an error.

5.2.4. "prepTime" Insertion

If the input document includes a "prepTime" attribute of <rfc>, exit
with an error.

Fill in the "prepTime" attribute of <rfc> with the current datetime.

5.2.5. <ol> Group "start" Insertion

Add a "start" attribute to every <ol> element containing a group that
does not already have a start.

5.2.6. Attribute Default Value Insertion

Fill in any default values for attributes on elements, except
"keepWithNext" and "keepWithPrevious" of <t>, and "toc" of <section>.
Some default values can be found in the RELAX NG schema, while others
can be found in the prose describing the elements in [RFC7991].

5.2.7. Section "toc" attribute

For each <section>, modify the "toc" attribute to be either "include"
or "exclude":

o for sections that have an ancestor of <boilerplate>, use "exclude"

Hoffman & Hildebrand Informational [Page 7]

RFC 7998 v3 Prep Tool December 2016

o else for sections that have a descendant that has toc="include",
use "include". If the ancestor section has toc="exclude" in the
input, this is an error.

o else for sections that are children of a section with
toc="exclude", use "exclude".

o else for sections that are deeper than rfc/@tocDepth, use
"exclude"

o else use "include"

5.2.8. "removeInRFC" Warning Paragraph

In I-D mode, if there is a <note> or <section> element with a
"removeInRFC" attribute that has the value "true", add a paragraph to
the top of the element with the text "This note is to be removed
before publishing as an RFC." or "This section...", unless a
paragraph consisting of that exact text already exists.

5.3. Normalization

These steps will ensure that ideas that can be expressed in multiple
different ways in the input document are only found in one way in the
prepared document.

5.3.1. "month" Attribute

Normalize the values of "month" attributes in all <date> elements in
<front> elements in <rfc> elements to numeric values.

5.3.2. ASCII Attribute Processing

In every <email>, <organization>, <street>, <city>, <region>,
<country>, and <code> element, if there is an "ascii" attribute and
the value of that attribute is the same as the content of the
element, remove the "ascii" element and issue a warning about the
removal.

In every <author> element, if there is an "asciiFullname",
"asciiInitials", or "asciiSurname" attribute, check the content of
that element against its matching "fullname", "initials", or
"surname" element (respectively). If the two are the same, remove
the "ascii*" element and issue a warning about the removal.

Hoffman & Hildebrand Informational [Page 8]

RFC 7998 v3 Prep Tool December 2016

5.3.3. "title" Conversion

For every <section>, <note>, <figure>, <references>, and <texttable>
element that has a (deprecated) "title" attribute, remove the "title"
attribute and insert a <name> element with the title from the
attribute.

5.4. Generation

These steps will generate new content, overriding existing similar
content in the input document. Some of these steps are important
enough that they specify a warning to be generated when the content
being overwritten does not match the new content.

5.4.1. "expiresDate" Insertion

If in I-D mode, fill in "expiresDate" attribute of <rfc> based on the
<date> element of the document's <front> element.

5.4.2. <boilerplate> Insertion

Create a <boilerplate> element if it does not exist. If there are
any children of the <boilerplate> element, produce a warning that
says "Existing boilerplate being removed. Other tools, specifically
the draft submission tool, will treat this condition as an error" and
remove the existing children.

5.4.2.1. Compare <rfc> "submissionType" and <seriesInfo> "stream"

Verify that <rfc> "submissionType" and <seriesInfo> "stream" are the
same if they are both present. If either is missing, add it. Note
that both have a default value of "IETF".

5.4.2.2. "Status of this Memo" Insertion

Add the "Status of this Memo" section to the <boilerplate> element
with current values. The application will use the "submissionType",
and "consensus" attributes of the <rfc> element, the <workgroup>
element, and the "status" and "stream" attributes of the <seriesInfo>
element, to determine which boilerplate from [RFC7841] to include, as
described in Appendix A of [RFC7991].

Hoffman & Hildebrand Informational [Page 9]

RFC 7998 v3 Prep Tool December 2016

5.4.2.3. "Copyright Notice" Insertion

Add the "Copyright Notice" section to the <boilerplate> element. The
application will use the "ipr" and "submissionType" attributes of the
<rfc> element and the <date> element to determine which portions and
which version of the Trust Legal Provisions (TLP) to use, as
described in A.1 of [RFC7991].

5.4.3. <reference> "target" Insertion

For any <reference> element that does not already have a "target"
attribute, fill the target attribute in if the element has one or
more <seriesinfo> child element(s) and the "name" attribute of the
<seriesinfo> element is "RFC", "Internet-Draft", or "DOI" or other
value for which it is clear what the "target" should be. The
particular URLs for RFCs, Internet-Drafts, and Digital Object
Identifiers (DOIs) for this step will be specified later by the RFC
Editor and the IESG. These URLs might also be different before and
after the v3 format is adopted.

5.4.4. <name> Slugification

Add a "slugifiedName" attribute to each <name> element that does not
contain one; replace the attribute if it contains a value that begins
with "n-".

5.4.5. <reference> Sorting

If the "sortRefs" attribute of the <rfc> element is true, sort the
<reference> and <referencegroup> elements lexically by the value of
the "anchor" attribute, as modified by the "to" attribute of any
<displayreference> element. The RFC Editor needs to determine what
the rules for lexical sorting are. The authors of this document
acknowledge that getting consensus on this will be a difficult task.

5.4.6. "pn" Numbering

Add "pn" attributes for all parts. Parts are:

o <section> in <middle>: pn='s-1.4.2'

o <references>: pn='s-12' or pn='s-12.1'

o <abstract>: pn='s-abstract'

o <note>: pn='s-note-2'

o <section> in <boilerplate>: pn='s-boilerplate-1'

Hoffman & Hildebrand Informational [Page 10]

RFC 7998 v3 Prep Tool December 2016

o <table>: pn='t-3'

o <figure>: pn='f-4'

o <artwork>, <aside>, <blockquote>, <dt>, <li>, <sourcecode>, <t>:
pn='p-[section]-[counter]'

5.4.7. <iref> Numbering

In every <iref> element, create a document-unique "pn" attribute.
The value of the "pn" attribute will start with 'i-', and use the
item attribute, the subitem attribute (if it exists), and a counter
to ensure uniqueness. For example, the first instance of "<iref
item='foo' subitem='bar'>" will have the "irefid" attribute set to
'i-foo-bar-1'.

5.4.8. <xref> Processing

5.4.8.1. "derivedContent" Insertion (with Content)

For each <xref> element that has content, fill the "derivedContent"
with the element content, having first trimmed the whitespace from
ends of content text. Issue a warning if the "derivedContent"
attribute already exists and has a different value from what was
being filled in.

5.4.8.2. "derivedContent" Insertion (without Content)

For each <xref> element that does not have content, fill the
"derivedContent" attribute based on the "format" attribute.

o For a value of "counter", the "derivedContent" is set to the
section, figure, table, or ordered list number of the element with
an anchor equal to the <xref> target.

o For format='default' and the "target" attribute points to a
<reference> or <referencegroup> element, the "derivedContent" is
the value of the "target" attribute (or the "to" attribute of a
<displayreference> element for the targeted <reference>).

o For format='default' and the "target" attribute points to a
<section>, <figure>, or <table>, the "derivedContent" is the name
of the thing pointed to, such as "Section 2.3", "Figure 12", or
"Table 4".

o For format='title', if the target is a <reference> element, the
"derivedContent" attribute is the name of the reference, extracted
from the <title> child of the <front> child of the reference.

Hoffman & Hildebrand Informational [Page 11]

RFC 7998 v3 Prep Tool December 2016

o For format='title', if the target element has a <name> child
element, the "derivedContent" attribute is the text content of
that <name> element concatenated with the text content of each
descendant node of <name> (that is, stripping out all of the XML
markup, leaving only the text).

o For format='title', if the target element does not contain a
<name> child element, the "derivedContent" attribute is the value
of the "target" attribute with no other adornment. Issue a
warning if the "derivedContent" attribute already exists and has a
different value from what was being filled in.

5.4.9. <relref> Processing

If any <relref> element's "target" attribute refers to anything but a
<reference> element, give an error.

For each <relref> element, fill in the "derivedLink" attribute.

5.5. Inclusion

These steps will include external files into the output document.

5.5.1. <artwork> Processing

1. If an <artwork> element has a "src" attribute where no scheme is
specified, copy the "src" attribute value to the "originalSrc"
attribute, and replace the "src" value with a URI that uses the
"file:" scheme in a path relative to the file being processed.
See Section 7 for warnings about this step. This will likely be
one of the most common authoring approaches.

2. If an <artwork> element has a "src" attribute with a "file:"
scheme, and if processing the URL would cause the processor to
retrieve a file that is not in the same directory, or a
subdirectory, as the file being processed, give an error. If the
"src" has any shellmeta strings (such as "`", "$USER", and so on)
that would be processed, give an error. Replace the "src"
attribute with a URI that uses the "file:" scheme in a path
relative to the file being processed. This rule attempts to
prevent <artwork src='file:///etc/passwd'> and similar security
issues. See Section 7 for warnings about this step.

3. If an <artwork> element has a "src" attribute, and the element
has content, give an error.

Hoffman & Hildebrand Informational [Page 12]

RFC 7998 v3 Prep Tool December 2016

4. If an <artwork> element has type='svg' and there is an "src"
attribute, the data needs to be moved into the content of the
<artwork> element.

* If the "src" URI scheme is "data:", fill the content of the
<artwork> element with that data and remove the "src"
attribute.

* If the "src" URI scheme is "file:", "http:", or "https:", fill
the content of the <artwork> element with the resolved XML
from the URI in the "src" attribute. If there is no
"originalSrc" attribute, add an "originalSrc" attribute with
the value of the URI and remove the "src" attribute.

* If the <artwork> element has an "alt" attribute, and the SVG
does not have a <desc> element, add the <desc> element with
the contents of the "alt" attribute.

5. If an <artwork> element has type='binary-art', the data needs to
be in an "src" attribute with a URI scheme of "data:". If the
"src" URI scheme is "file:", "http:", or "https:", resolve the
URL. Replace the "src" attribute with a "data:" URI, and add an
"originalSrc" attribute with the value of the URI. For the
"http:" and "https:" URI schemes, the mediatype of the "data:"
URI will be the Content-Type of the HTTP response. For the
"file:" URI scheme, the mediatype of the "data:" URI needs to be
guessed with heuristics (this is possibly a bad idea). This also
fails for content that includes binary images but uses a type
other than "binary-art". Note: since this feature can't be used
for RFCs at the moment, this entire feature might be

6. If an <artwork> element does not have type='svg' or
type='binary-art' and there is an "src" attribute, the data needs
to be moved into the content of the <artwork> element. Note that
this step assumes that all of the preferred types other than
"binary-art" are text, which is possibly wrong.

* If the "src" URI scheme is "data:", fill the content of the
<artwork> element with the correctly escaped form of that data
and remove the "src" attribute.

* If the "src" URI scheme is "file:", "http:", or "https:", fill
the content of the <artwork> element with the correctly
escaped form of the resolved text from the URI in the "src"
attribute. If there is no "originalSrc" attribute, add an
"originalSrc" attribute with the value of the URI and remove
the "src" attribute.

Hoffman & Hildebrand Informational [Page 13]

RFC 7998 v3 Prep Tool December 2016

5.5.2. <sourcecode> Processing

1. If a <sourcecode> element has a "src" attribute where no scheme
is specified, copy the "src" attribute value to the "originalSrc"
attribute and replace the "src" value with a URI that uses the
"file:" scheme in a path relative to the file being processed.
See Section 7 for warnings about this step. This will likely be
one of the most common authoring approaches.

2. If a <sourcecode> element has a "src" attribute with a "file:"
scheme, and if processing the URL would cause the processor to
retrieve a file that is not in the same directory, or a
subdirectory, as the file being processed, give an error. If the
"src" has any shellmeta strings (such as "`", "$USER", and so on)
that would be processed, give an error. Replace the "src"
attribute with a URI that uses the "file:" scheme in a path
relative to the file being processed. This rule attempts to
prevent <sourcecode src='file:///etc/passwd'> and similar
security issues. See Section 7 for warnings about this step.

3. If a <sourcecode> element has a "src" attribute, and the element
has content, give an error.

4. If a <sourcecode> element has a "src" attribute, the data needs
to be moved into the content of the <sourcecode> element.

* If the "src" URI scheme is "data:", fill the content of the
<sourcecode> element with that data and remove the "src"
attribute.

* If the "src" URI scheme is "file:", "http:", or "https:", fill
the content of the <sourcecode> element with the resolved XML
from the URI in the "src" attribute. If there is no
"originalSrc" attribute, add an "originalSrc" attribute with
the value of the URI and remove the "src" attribute.

5.6. RFC Production Mode Cleanup

These steps provide extra cleanup of the output document in RFC
production mode.

5.6.1. <note> Removal

In RFC production mode, if there is a <note> or <section> element
with a "removeInRFC" attribute that has the value "true", remove the
element.

Hoffman & Hildebrand Informational [Page 14]

RFC 7998 v3 Prep Tool December 2016

5.6.2. <cref> Removal

If in RFC production mode, remove all <cref> elements.

5.6.3. <link> Processing

1. If in RFC production mode, remove all <link> elements whose "rel"
attribute has the value "alternate".

2. If in RFC production mode, check if there is a <link> element
with the current ISSN for the RFC series (2070-1721); if not, add
<link rel="item" href="urn:issn:2070-1721">.

3. If in RFC production mode, check if there is a <link> element
with a DOI for this RFC; if not, add one of the form <link
rel="describedBy" href="https://dx.doi.org/10.17487/rfcdd"> where
"dd" is the number of the RFC, such as
"https://dx.doi.org/10.17487/rfc2109". The URI is described in
[RFC7669]. If there was already a <link> element with a DOI for
this RFC, check that the "href" value has the right format. The
content of the href attribute is expected to change in the
future.

4. If in RFC production mode, check if there is a <link> element
with the file name of the Internet-Draft that became this RFC the
form <link rel="convertedFrom"
href="https://datatracker.ietf.org/doc/draft-tttttttttt/">. If
one does not exist, give an error.

5.6.4. XML Comment Removal

If in RFC production mode, remove XML comments.

5.6.5. "xml:base" and "originalSrc" Removal

If in RFC production mode, remove all "xml:base" or "originalSrc"
attributes from all elements.

5.6.6. Compliance Check

If in RFC production mode, ensure that the result is in full
compliance to the v3 schema, without any deprecated elements or
attributes and give an error if any issues are found.

5.7. Finalization

These steps provide the finishing touches on the output document.

Hoffman & Hildebrand Informational [Page 15]

RFC 7998 v3 Prep Tool December 2016

5.7.1. "scripts" Insertion

Determine all the characters used in the document and fill in the
"scripts" attribute for <rfc>.

5.7.2. Pretty-Format

Pretty-format the XML output. (Note: there are many tools that do an
adequate job.)

6. Additional Uses for the Prep Tool

There will be a need for Internet-Draft authors who include files
from their local disk (such as for <artwork src="mydrawing.svg"/>) to
have the contents of those files inlined to their drafts before
submitting them to the Internet-Draft processor. (There is a
possibility that the Internet-Draft processor will allow XML files
and accompanying files to be submitted at the same time, but this
seems troublesome from a security, portability, and complexity
standpoint.) For these users, having a local copy of the prep tool
that has an option to just inline all local files would be terribly
useful. That option would be a proper subset of the steps given in
Section 5.

A feature that might be useful in a local prep tool would be the
inverse of the "just inline" option would be "extract all". This
would allow a user who has a v3 RFC or Internet-Draft to dump all of
the <artwork> and <sourcecode> elements into local files instead of
having to find each one in the XML. This option might even do as
much validation as possible on the extracted <sourcecode> elements.
This feature might also remove some of the features added by the prep
tool (such as part numbers and "slugifiedName" attributes starting
with "n-") in order to make the resulting file easier to edit.

7. Security Considerations

Steps in this document attempt to prevent the <artwork> and
<sourcecode> entities from exposing the contents of files outside the
directory in which the document being processed resides. For
example, values starting with "/", "./", or "../" should generate
errors.

The security considerations in [RFC3470] apply here. Specifically,
processing XML-external references can expose a prep-tool
implementation to various threats by causing the implementation to
access external resources automatically. It is important to disallow
arbitrary access to such external references within XML data from
untrusted sources.

Hoffman & Hildebrand Informational [Page 16]

RFC 7998 v3 Prep Tool December 2016

8. Informative References

[IDNITS] IETF Tools, "Idnits Tool",
<https://tools.ietf.org/tools/idnits/>.

[PUB-PROCESS]
RFC Editor, "Publication Process",
<https://www.rfc-editor.org/pubprocess/>.

[RFC3470] Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines for
the Use of Extensible Markup Language (XML) within IETF
Protocols", BCP 70, RFC 3470, DOI 10.17487/RFC3470,
January 2003, <http://www.rfc-editor.org/info/rfc3470>.

[RFC6949] Flanagan, H. and N. Brownlee, "RFC Series Format
Requirements and Future Development", RFC 6949,
DOI 10.17487/RFC6949, May 2013,
<http://www.rfc-editor.org/info/rfc6949>.

[RFC7669] Levine, J., "Assigning Digital Object Identifiers to
RFCs", RFC 7669, DOI 10.17487/RFC7669, October 2015,
<http://www.rfc-editor.org/info/rfc7669>.

[RFC7841] Halpern, J., Ed., Daigle, L., Ed., and O. Kolkman, Ed.,
"RFC Streams, Headers, and Boilerplates", RFC 7841,
DOI 10.17487/RFC7841, May 2016,
<http://www.rfc-editor.org/info/rfc7841>.

[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
RFC 7991, DOI 10.17487/RFC7991, December 2016,
<http://www.rfc-editor.org/info/rfc7991>.

Hoffman & Hildebrand Informational [Page 17]

RFC 7998 v3 Prep Tool December 2016

IAB Members at the Time of Approval

The IAB members at the time this memo was approved were (in
alphabetical order):

Jari Arkko
Ralph Droms
Ted Hardie
Joe Hildebrand
Russ Housley
Lee Howard
Erik Nordmark
Robert Sparks
Andrew Sullivan
Dave Thaler
Martin Thomson
Brian Trammell
Suzanne Woolf

Acknowledgements

Many people contributed valuable ideas to this document. Special
thanks go to Robert Sparks for his in-depth review and contributions
early in the development of this document and to Julian Reschke for
his help getting the document structured more clearly.

Authors' Addresses

Paul Hoffman
ICANN

Email: [email protected]

Joe Hildebrand
Mozilla

Email: [email protected]

Hoffman & Hildebrand Informational [Page 18]