SocketCAN: Allow specifying the protocol to use

So far, only CAN_RAW was allowed, but there might be
cases where other protocols are useful too.

The default value is still CAN_RAW, so all existing
applications will continue working.

[ChangeLog][SocketCAN] Added the configuration parameter
QCanBusDevice::ProtocolKey to use another protocol
inside the protocol family PF_CAN.

Fixes: QTBUG-75204
Change-Id: I8323ab8d77a569f51d3cd8c296b433352a3f5609
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

2 files changed, 12 insertions, 1 deletions

diff --git a/src/plugins/canbus/socketcan/socketcanbackend.cpp b/src/plugins/canbus/socketcan/socketcanbackend.cpp
index 27fa326..2ed1310 100644
--- a/src/plugins/canbus/socketcan/socketcanbackend.cpp
+++ b/src/plugins/canbus/socketcan/socketcanbackend.cpp
@@ -389,7 +389,7 @@ bool SocketCanBackend::connectSocket()
 {
     struct ifreq interface;
 
-    if (Q_UNLIKELY((canSocket = socket(PF_CAN, SOCK_RAW | SOCK_NONBLOCK, CAN_RAW)) < 0)) {
+    if (Q_UNLIKELY((canSocket = socket(PF_CAN, SOCK_RAW | SOCK_NONBLOCK, protocol)) < 0)) {
         setError(qt_error_string(errno),
                  QCanBusDevice::CanBusError::ConnectionError);
         return false;
@@ -464,6 +464,16 @@ void SocketCanBackend::setConfigurationParameter(int key, const QVariant &value)
                 return;
             }
         }
+    } else if (key == QCanBusDevice::ProtocolKey) {
+        bool ok = false;
+        const int newProtocol = value.toInt(&ok);
+        if (Q_UNLIKELY(!ok || (newProtocol < 0))) {
+            const QString errorString = tr("Cannot set protocol to value %1.").arg(value.toString());
+            setError(errorString, QCanBusDevice::ConfigurationError);
+            qCWarning(QT_CANBUS_PLUGINS_SOCKETCAN, "%ls", qUtf16Printable(errorString));
+            return;
+        }
+        protocol = newProtocol;
     }
     // connected & params not applyable/invalid
     if (canSocket != -1 && !applyConfigurationParameter(key, value))
diff --git a/src/plugins/canbus/socketcan/socketcanbackend.h b/src/plugins/canbus/socketcan/socketcanbackend.h
index 199401e..0497244 100644
--- a/src/plugins/canbus/socketcan/socketcanbackend.h
+++ b/src/plugins/canbus/socketcan/socketcanbackend.h
@@ -87,6 +87,7 @@ private:
     bool hasBusStatus() const;
     QCanBusDevice::CanBusStatus busStatus() const;
 
+    int protocol = CAN_RAW;
     canfd_frame m_frame;
     sockaddr_can m_address;
     msghdr m_msg;