Log CAN frames to the event loop

This will make it easier to debug CAN problems in the future.

Signed-off-by: Ravago Jones <ravagojones@gmail.com>
Change-Id: I589b2d039fc101c6fd988579dd11239179a48415
diff --git a/frc971/can_logger/can_logger.h b/frc971/can_logger/can_logger.h
new file mode 100644
index 0000000..cf37841
--- /dev/null
+++ b/frc971/can_logger/can_logger.h
@@ -0,0 +1,50 @@
+#ifndef FRC971_CAN_LOGGER_CAN_LOGGER_H_
+#define FRC971_CAN_LOGGER_CAN_LOGGER_H_
+
+#include <linux/can.h>
+#include <linux/can/raw.h>
+#include <linux/sockios.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+
+#include <chrono>
+
+#include "aos/events/event_loop.h"
+#include "aos/realtime.h"
+#include "aos/scoped/scoped_fd.h"
+#include "frc971/can_logger/can_logging_generated.h"
+
+namespace frc971 {
+namespace can_logger {
+
+// This class listens to all the traffic on a SocketCAN interface and sends it
+// on the aos event loop so it can be logged with the aos logging
+// infrastructure.
+class CanLogger {
+ public:
+  static constexpr std::chrono::milliseconds kPollPeriod =
+      std::chrono::milliseconds(100);
+
+  CanLogger(aos::EventLoop *event_loop,
+            std::string_view interface_name = "can0");
+
+  CanLogger(const CanLogger &) = delete;
+  CanLogger &operator=(const CanLogger &) = delete;
+
+ private:
+  void Poll();
+
+  // Read a CAN frame from the socket and send it on the event loop
+  // Returns true if successful and false if the recieve buffer is empty.
+  bool ReadFrame();
+
+  aos::ScopedFD fd_;
+  aos::Sender<CanFrame> frames_sender_;
+};
+
+}  // namespace can_logger
+}  // namespace frc971
+
+#endif  // FRC971_CAN_LOGGER_CAN_LOGGER_H_