From d1288b4e6ef9accc6fec412aa78373b3775b67d9 Mon Sep 17 00:00:00 2001
From: Luke Dashjr <luke-jr+git@utopios.org>
Date: Sat, 15 Sep 2012 04:20:34 +0000
Subject: [PATCH] Check block version for compatibility, honouring
 version/force and version/reduce mutations if allowed

---
 blkmaker_jansson.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/blkmaker_jansson.c b/blkmaker_jansson.c
index 85c543d..faa4bc7 100644
--- a/blkmaker_jansson.c
+++ b/blkmaker_jansson.c
@@ -245,6 +245,15 @@ const char *blktmpl_add_jansson(blktemplate_t *tmpl, const json_t *json, time_t
 		}
 	}
 	
+	if (tmpl->version > 2 || (tmpl->version == 2 && !tmpl->height))
+	{
+		if (tmpl->mutations & BMM_VERDROP)
+			tmpl->version = tmpl->height ? 2 : 1;
+		else
+		if (!(tmpl->mutations & BMM_VERFORCE))
+			return "Unrecognized block version, and not allowed to reduce or force it";
+	}
+	
 	tmpl->_time_rcvd = time_rcvd;
 	
 	return NULL;