ofp-util: Add comment to ofputil_postappend_stats_reply().

It seemed like it could use one.

Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/lib/ofp-util.c b/lib/ofp-util.c
index d9a77f1ebb7086e82f8793c0fb01993057ea24f0..99f92a8cca28f074052cea486bcb76917ac35d12 100644 (file)
--- a/lib/ofp-util.c
+++ b/lib/ofp-util.c
@@ -3392,6 +3392,16 @@ ofputil_append_stats_reply(size_t len, struct list *replies)
     return ofpbuf_put_uninit(ofputil_reserve_stats_reply(len, replies), len);
 }
 
+/* Sometimes, when composing stats replies, it's difficult to predict how long
+ * an individual reply chunk will be before actually encoding it into the reply
+ * buffer.  This function allows easy handling of this case: just encode the
+ * reply, then use this function to break the message into two pieces if it
+ * exceeds the OpenFlow message limit.
+ *
+ * In detail, if the final stats message in 'replies' is too long for OpenFlow,
+ * this function breaks it into two separate stats replies, the first one with
+ * the first 'start_ofs' bytes, the second one containing the bytes from that
+ * offset onward. */
 void
 ofputil_postappend_stats_reply(size_t start_ofs, struct list *replies)
 {