[tor-commits] [torspec/main] Be explicit about EXT_FIELD_LEN=0

[nickm at torproject.org]

commit fa940c0d9e30d52b168d0ee64bec08c0a88f4edb
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Feb 17 16:16:15 2022 -0500

    Be explicit about EXT_FIELD_LEN=0
---
 proposals/332-ntor-v3-with-extra-data.md | 2 ++
 rend-spec-v3.txt                         | 1 +
 2 files changed, 3 insertions(+)

diff --git a/proposals/332-ntor-v3-with-extra-data.md b/proposals/332-ntor-v3-with-extra-data.md
index 8e6dedc..25ae0ba 100644
--- a/proposals/332-ntor-v3-with-extra-data.md
+++ b/proposals/332-ntor-v3-with-extra-data.md
@@ -343,6 +343,8 @@ server messages.
        EXT_FIELD_LEN      [one byte]
        EXT_FIELD          [EXT_FIELD_LEN bytes]
 
+(`EXT_FIELD_LEN` may be zero, in which case EXT_FIELD is absent.)
+
 All parties MUST reject messages that are not well-formed per the
 rules above.
 
diff --git a/rend-spec-v3.txt b/rend-spec-v3.txt
index 1a0b945..fac1395 100644
--- a/rend-spec-v3.txt
+++ b/rend-spec-v3.txt
@@ -1550,6 +1550,7 @@ Table of contents:
    The EXT_FIELD_TYPE, EXT_FIELD_LEN, EXT_FIELD entries are reserved for
    extensions to the introduction protocol. Extensions with
    unrecognized EXT_FIELD_TYPE values must be ignored.
+   (`EXT_FIELD_LEN` may be zero, in which case EXT_FIELD is absent.)
 
    Unless otherwise specified in the documentation for an extension type:
       * Each extension type SHOULD be sent only once in a message.