Fix combination of Mode = router and DeviceType = tap on Linux.

I believe I have found a bug in tinc on Linux when it is used with
Mode = router and DeviceType = tap. This combination is useful because
it allows global broadcast packets to be used in router mode. However,
when tinc receives a packet in this situation, it needs to make sure its
destination MAC address matches the address of the TAP adapter, which is
typically not the case since the sending node doesn't know the MAC
address of the recipient. Unfortunately, this is not the case on Linux,
which breaks connectivity.

diff --git a/src/linux/device.c b/src/linux/device.c
index 3b3b439df034c4364f0cd0e2b162c1c805242200..127e3e828488c146c380f5db1384eda0edcb9909 100644 (file)
--- a/src/linux/device.c
+++ b/src/linux/device.c
@@ -84,6 +84,8 @@ static bool setup_device(void) {
                device_type = DEVICE_TYPE_TUN;
                device_info = "Linux tun/tap device (tun mode)";
        } else {
+               if (routing_mode == RMODE_ROUTER)
+                       overwrite_mac = true;
                ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
                device_type = DEVICE_TYPE_TAP;
                device_info = "Linux tun/tap device (tap mode)";