e1d: Add watchdog timer to detect dead lines / USB devices

We just found a bug in icE1usb (likely firmware) which was hard to find
as there was zero notification from osmo-e1d that it actually never
received any data from the icE1usb hardware/firmware anymore.

Change-Id: Id22e4110b9067f50b1818eb12295b2d4eb9cdc12

3 files changed, 29 insertions, 0 deletions

diff --git a/src/e1d.h b/src/e1d.h
index af6c09e..618776d 100644
--- a/src/e1d.h
+++ b/src/e1d.h
@@ -123,6 +123,12 @@ struct e1_line {
 		struct osmo_timer_list timer;
 	} ts0;
 
+	/* watchdog timer to catch situations where no more USB data is received */
+	struct {
+		struct osmo_timer_list timer;
+		uint32_t rx_bytes;
+	} watchdog;
+
 	void *e1gen_priv;
 };
 
diff --git a/src/intf_line.c b/src/intf_line.c
index 5143e45..5659129 100644
--- a/src/intf_line.c
+++ b/src/intf_line.c
@@ -35,6 +35,7 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/core/stats.h>
 #include <osmocom/core/rate_ctr.h>
+#include <osmocom/core/timer.h>
 #include <osmocom/e1d/proto.h>
 
 #include "e1d.h"
@@ -64,6 +65,20 @@ static const struct rate_ctr_group_desc line_ctrg_desc = {
 	.ctr_desc = line_ctr_description,
 };
 
+/* watchdog timer, called once per second to check if we still receive data on the line */
+static void line_watchdog_cb(void *data)
+{
+	struct e1_line *line = data;
+
+	if (line->watchdog.rx_bytes < 240000) {
+		LOGPLI(line, DE1D, LOGL_ERROR, "Received Only %u bytes/s (expected: 262144): Line dead?\n",
+			line->watchdog.rx_bytes);
+	}
+
+	line->watchdog.rx_bytes = 0;
+	osmo_timer_schedule(&line->watchdog.timer, 1, 0);
+}
+
 // ---------------------------------------------------------------------------
 // e1d structures
 // ---------------------------------------------------------------------------
@@ -196,6 +211,10 @@ e1_line_new(struct e1_intf *intf, void *drv_data)
 
 	llist_add_tail(&line->list, &intf->lines);
 
+	/* start watchdog timer */
+	osmo_timer_setup(&line->watchdog.timer, line_watchdog_cb, line);
+	osmo_timer_schedule(&line->watchdog.timer, 1, 0);
+
 	LOGPLI(line, DE1D, LOGL_NOTICE, "Created\n");
 
 	return line;
@@ -206,6 +225,8 @@ e1_line_destroy(struct e1_line *line)
 {
 	LOGPLI(line, DE1D, LOGL_NOTICE, "Destroying\n");
 
+	osmo_timer_del(&line->watchdog.timer);
+
 	/* close all [peer] file descriptors */
 	for (int i=0; i<32; i++)
 		e1_ts_stop(&line->ts[i]);
diff --git a/src/mux_demux.c b/src/mux_demux.c
index 341256a..b0a9cf2 100644
--- a/src/mux_demux.c
+++ b/src/mux_demux.c
@@ -391,6 +391,8 @@ e1_line_demux_in(struct e1_line *line, const uint8_t *buf, int size, int frame_b
 		return -1;
 	}
 
+	line->watchdog.rx_bytes += size;
+
 	ftr = size / 32;
 	OSMO_ASSERT(size % 32 == 0);