[PATCH v2 14/16] ratp: don't ignore data that may arrive in behaviour H1

[Aleksander Morgado]

If an input packet arrives H1 that has data in it, we need to:
  * track sn_received
  * if we have data pending, send it
  * if we don't have data pending, send a plain ACK

This process, as noted in RFC916, is the same as the I1 procedure, so
go and run it:

     Go to the ESTABLISHED state and execute procedure I1 to process
     any data which might be in this packet.

This fix allows the peer to queue data in the last packet doing the
connection establishment. It doesn't apply to the barebox<->bbremote
interaction because bbremote won't queue data until the connection is
completely established, but it allows third party ratp implementations
to do that.

Signed-off-by: Aleksander Morgado <aleksander at aleksander.es>
---
 lib/ratp.c             |  8 +++++++-
 scripts/remote/ratp.py | 14 ++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/lib/ratp.c b/lib/ratp.c
index e810a9e54..2dee41009 100644
--- a/lib/ratp.c
+++ b/lib/ratp.c
@@ -1042,6 +1042,8 @@ static int ratp_behaviour_g(struct ratp_internal *ri, void *pkt)
 	return 0;
 }
 
+static int ratp_behaviour_i1(struct ratp_internal *ri, void *pkt);
+
 /*
  * Our SYN has been acknowledged.  At this point we are
  * technically in the ESTABLISHED state.  Send any initial data
@@ -1062,7 +1064,11 @@ static int ratp_behaviour_h1(struct ratp_internal *ri, void *pkt)
 
 	ratp_state_change(ri, RATP_STATE_ESTABLISHED);
 
-	return 0;
+	/* If the input message has data (i.e. it is not just an ACK
+	 * without data) then we need to send back an ACK ourselves,
+	 * or even data if we have it pending. This is the same
+	 * procedure done in i1, so just run it. */
+	return ratp_behaviour_i1 (ri, pkt);
 }
 
 /*
diff --git a/scripts/remote/ratp.py b/scripts/remote/ratp.py
index e6b3e19b6..7972d31f2 100644
--- a/scripts/remote/ratp.py
+++ b/scripts/remote/ratp.py
@@ -489,12 +489,8 @@ class RatpConnection(object):
 
     def _h1(self, r):
         logging.info("H1")
-
-        # FIXME: initial data?
         self._state = RatpState.established
-        self._r_sn = r.c_sn
-
-        return False
+        return self._common_i1(r)
 
     def _h2(self, r):
         logging.info("H2")
@@ -584,9 +580,7 @@ class RatpConnection(object):
         self._time_wait_deadline = monotonic() + self._get_rto()
         return False
 
-    def _i1(self, r):
-        logging.info("I1")
-
+    def _common_i1(self, r):
         if r.c_so:
             self._r_sn = r.c_sn
             self._rx_buf.append(chr(r.length))
@@ -608,6 +602,10 @@ class RatpConnection(object):
         self._write(s)
         return False
 
+    def _i1(self, r):
+        logging.info("I1")
+        return self._common_i1(r)
+
     def _machine(self, pkt):
         logging.info("State: %r", self._state)
         if self._state == RatpState.listen:
-- 
2.13.1