Fix: Avoid returning negative value that's stop watch socket

Even if the frame read is wrong doesn't mean that socket is compromise only
that communication on CAN bus is difficult, maybe temporary. On en EPOLL err
code, or hangup, just close and restart the socket and reset the filter.

Change-Id: I61f146fd269bb2524f09e1f2ed89d93e83166136
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

3 files changed, 12 insertions, 7 deletions

diff --git a/CAN-binder/low-can-binding/binding/low-can-cb.cpp b/CAN-binder/low-can-binding/binding/low-can-cb.cpp
index 414fa910..21838936 100644
--- a/CAN-binder/low-can-binding/binding/low-can-cb.cpp
+++ b/CAN-binder/low-can-binding/binding/low-can-cb.cpp
@@ -55,9 +55,16 @@ void on_no_clients(std::string message)
 int read(sd_event_source *s, int fd, uint32_t revents, void *userdata)
 {
 	can_signal_t* sig= (can_signal_t*)userdata;
-	if(sig->read_socket() != can_message_format_t::ERROR)
-		return 0;
-	return -1;
+	sig->read_socket();
+
+	/* check if error or hangup */
+	if ((revents & (EPOLLERR|EPOLLRDHUP|EPOLLHUP)) != 0)
+	{
+		sd_event_source_unref(s);
+		sig->get_socket().close();
+		sig->create_rx_filter();
+	}
+	return 0;
 }
 
 ///******************************************************************************
diff --git a/CAN-binder/low-can-binding/can/can-signals.cpp b/CAN-binder/low-can-binding/can/can-signals.cpp
index c8098a51..d072fb36 100644
--- a/CAN-binder/low-can-binding/can/can-signals.cpp
+++ b/CAN-binder/low-can-binding/can/can-signals.cpp
@@ -235,7 +235,7 @@ int can_signal_t::create_rx_filter()
 	return -1;
 }
 
-can_message_format_t can_signal_t::read_socket()
+void can_signal_t::read_socket()
 {
 	can_message_t msg;
 	can_bus_t& cbm = configuration_t::instance().get_can_bus_manager();
@@ -243,6 +243,4 @@ can_message_format_t can_signal_t::read_socket()
 	std::lock_guard<std::mutex> can_message_lock(cbm.get_can_message_mutex());
 	{ cbm.push_new_can_message(msg); }
 	cbm.get_new_can_message_cv().notify_one();
-
-	return msg.get_format();
 }
\ No newline at end of file
diff --git a/CAN-binder/low-can-binding/can/can-signals.hpp b/CAN-binder/low-can-binding/can/can-signals.hpp
index 8196c7eb..6152b79a 100644
--- a/CAN-binder/low-can-binding/can/can-signals.hpp
+++ b/CAN-binder/low-can-binding/can/can-signals.hpp
@@ -159,5 +159,5 @@ public:
 	void set_last_value(float val);
 
 	int create_rx_filter();
-	can_message_format_t read_socket();
+	void read_socket();
 };
\ No newline at end of file