EtherateMT starts when interface is down

[jwbensley]

EtherateMT doesn't check if the interface is physically up and will send traffic out of an interface which is down;

This is an interace that is disabled with sudo ip link set down dev eth2:

bensley@htpc-ubuntu:~/c/EtherateMT$ sudo ./etherate_mt -i eth2
Using inteface eth2 (4).
Setting interface promiscuous mode
Frame size set to 1514 bytes.
Using raw packet socket with send()/read().
Running in Tx mode.
17927:Socket Tx error (Network is down)
Removing interface promiscuous mode

This is an interface which is up (sudo ip link set up dev eth2) but the cable is disconnected:

bensley@htpc-ubuntu:~/c/EtherateMT$ sudo ./etherate_mt -i eth2
Using inteface eth2 (4).
Setting interface promiscuous mode
Frame size set to 1514 bytes.
Using raw packet socket with send()/read().
Running in Tx mode.
0.	Rx: 0.00 Gbps (0 fps)	Tx: 22.66 Gbps (1871223 fps)
1.	Rx: 0.00 Gbps (0 fps)	Tx: 22.90 Gbps (1890306 fps)
2.	Rx: 0.00 Gbps (0 fps)	Tx: 22.89 Gbps (1889481 fps)
^CQuitting...
Removing interface promiscuous mode

[jwbensley]

From: https://github.com/jwbensley/Etherate/blob/master/functions.c#L1349

                    // Is this interface even up?
                    if (ioctl(intf->sock_fd, SIOCGIFFLAGS, &ifreq) == -1) break;
                    if (!(ifreq.ifr_flags & IFF_UP && ifreq.ifr_flags & IFF_RUNNING)) break;