ja3_fingerprint.so docs: --modify-incoming (#11226)
This adds a description for --modify-incoming to the ja3_fingerprint.so
docs.
(cherry picked from commit 2014479155bee9744daa419321718b94ff93440f)
diff --git a/doc/admin-guide/plugins/ja3_fingerprint.en.rst b/doc/admin-guide/plugins/ja3_fingerprint.en.rst
index 62bf316..faada25 100644
--- a/doc/admin-guide/plugins/ja3_fingerprint.en.rst
+++ b/doc/admin-guide/plugins/ja3_fingerprint.en.rst
@@ -55,7 +55,6 @@
.. option:: --ja3log
-
This option enables logging to the file ``ja3_fingerprint.log`` in the standard logging
directory. The format is ::
@@ -63,6 +62,19 @@
By default this is not enabled.
+.. option:: --modify-incoming
+
+ As described above, typically, the ``X-JA3-Sig`` header is added to the request as it is sent
+ upstream so that any upstream hosts can make use of it. The ``--modify-incoming`` option
+ instructs the plugin to add the ``X-JA3-Sig`` header field earlier on the incoming request so
+ that other plugins can make use of it while processing the request. To be precise,
+ ``--modify-incoming`` adds the ``X-JA3-Sig`` header field in the
+ ``TS_HTTP_READ_REQUEST_HDR_HOOK`` hook rather than the default ``TS_HTTP_SEND_REQUEST_HDR_HOOK``
+ hook.
+
+ This option is only useful when the plugin is configured as a global plugin. By default this
+ is not enabled.
+
Requirement
=============
