BUG/MEDIUM: bwlim: Reset analyse expiration date when then channel analyse ends

The bandwidth limitation filter sets the analyse expiration date on the
channel to restart the data forwarding and thus limit the bandwidth.
However, this expiration date is not reset on abort. So it is possible to
reuse the same expiration date to set the stream one. If it expired before
the end of the stream, this will lead to a spinning loop on process_stream()
because the task expiration date is always set in past.

To fix the issue, when the analyse ends on a channel, the bandwidth
limitation filter reset the corrsponding analyse expiration date.

This patch should fix the issue #2230. It must be backported as far as 2.7.

(cherry picked from commit f1bf0b1a6bafedf807d91643b6a09120d2a57e18)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
diff --git a/src/flt_bwlim.c b/src/flt_bwlim.c
index c9cdf2f..27db231 100644
--- a/src/flt_bwlim.c
+++ b/src/flt_bwlim.c
@@ -289,6 +289,18 @@
 }
 
 /**************************************************************************
+ * Hooks to handle channels activity
+ *************************************************************************/
+
+/* Called when analyze ends for a given channel */
+static int bwlim_chn_end_analyze(struct stream *s, struct filter *filter, struct channel *chn)
+{
+	chn->analyse_exp = TICK_ETERNITY;
+        return 1;
+}
+
+
+/**************************************************************************
  * Hooks to filter HTTP messages
  *************************************************************************/
 static int bwlim_http_headers(struct stream *s, struct filter *filter, struct http_msg *msg)
@@ -325,6 +337,8 @@
 	.attach             = bwlim_attach,
 	.detach             = bwlim_detach,
 
+	        /* Handle channels activity */
+        .channel_end_analyze = bwlim_chn_end_analyze,
 
 	/* Filter HTTP requests and responses */
 	.http_headers        = bwlim_http_headers,