From c77021231c32119f2262465df069df10e50c6f55 Mon Sep 17 00:00:00 2001
From: Eric House <eehouse@fit>
Date: Sun, 30 Jun 2013 08:33:29 -0700
Subject: [PATCH] print checksums of sent and received messages

---
 xwords4/common/comms.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/xwords4/common/comms.c b/xwords4/common/comms.c
index b0578dbda..729cabe31 100644
--- a/xwords4/common/comms.c
+++ b/xwords4/common/comms.c
@@ -1204,6 +1204,11 @@ sendMsg( CommsCtxt* comms, MsgQueueElem* elem )
 
     channelNo = elem->channelNo;
 
+#ifdef COMMS_CHECKSUM
+    XP_LOGF( "%s: sending message of len %d with sum %s", __func__, elem->len, 
+             elem->checksum );
+#endif
+
     if ( 0 ) {
 #ifdef XWFEATURE_RELAY
     } else if ( conType == COMMS_CONN_RELAY ) {
@@ -1809,6 +1814,9 @@ comms_checkIncomingStream( CommsCtxt* comms, XWStreamCtxt* stream,
     XP_Bool usingRelay = XP_FALSE;
 
     XP_ASSERT( retAddr == NULL || comms->addr.conType == retAddr->conType );
+#ifdef COMMS_CHECKSUM
+    XP_U16 initialLen = stream_getSize( stream );
+#endif
 
     if ( !preProcess( comms, stream, &usingRelay, &senderID ) ) {
         XP_U32 connID;
@@ -1816,6 +1824,17 @@ comms_checkIncomingStream( CommsCtxt* comms, XWStreamCtxt* stream,
         MsgID msgID;
         MsgID lastMsgRcd;
 
+#ifdef COMMS_CHECKSUM
+        {
+            XP_U16 len = stream_getSize( stream );
+            // stream_getPtr pts at base, but sum excludes relay header
+            const XP_U8* ptr = initialLen - len + stream_getPtr( stream );
+            gchar* sum = g_compute_checksum_for_data( G_CHECKSUM_MD5, ptr, len );
+            XP_LOGF( "%s: got message of len %d with sum %s", __func__, len, sum );
+            g_free( sum );
+        }
+#endif
+
         /* reject too-small message */
         if ( stream_getSize( stream ) >=
              (sizeof(connID) + sizeof(channelNo)