doc/dev/msgr2: checksum frame header (tag + length)

Ensure we catch transport errors early (before we, say, try to allocate
a missized payload buffer).

Signed-off-by: Sage Weil <sage@redhat.com>

diff --git a/doc/dev/msgr2.rst b/doc/dev/msgr2.rst
index 83ec7c0b4096a8830a835895470a6e68311d5ad2..78ce017dea94fbabc499ff8d82f43f4b851b03eb 100644 (file)
--- a/doc/dev/msgr2.rst
+++ b/doc/dev/msgr2.rst
@@ -82,10 +82,14 @@ the form::
 
   frame_len (le32)
   tag (TAG_* le32)
+  frame_header_checksum (le32)
   payload
   [payload padding -- only present after stream auth phase]
   [signature -- only present after stream auth phase]
 
+
+* The frame_header_checksum is over just the frame_len and tag values (8 bytes).
+
 * frame_len includes everything after the frame_len le32 up to the end of the
   frame (all payloads, signatures, and padding).