a simple utility to fake IPv4 traceroute path, optionally with MPLS labels.
usage: ./traced -T -p PATHDEF_FILE -t TUN_IFNAME
usage: ./traced -I -p PATHDEF_FILE -i IN_IFNAME -o OUT_IFNAME -d DST_MAC
modes:
-T: tun mode - traffic needs to be routed into the tun interface.
-I: inline mode - sniff low-ttl traffic from IN_IFNAME, and sends reply to
DST_MAC on OUT_IFNAME.
see path.conf.example for an example of PATHDEF_FILE.
to use tap mode (assuming you want to tun interface to be named tun0):
$ sudo ./traced -Tp path.conf -i tun0
then, bring the tun0 interface up, route some network(s) to it, then do a trace:
$ sudo ip link set tun0 up
$ sudo ip route add x.x.x.x/32 dev tun0
$ traceroute -e x.x.x.x
inline mode sniff packets from given interface with AF_PACKET, then send out ICMP messages for low TTL packets to given dst mac on given interface.
to use inline mode (assuming sniffing from eth0 and replying to 00:00:00:00:00:01 on eth1):
$ sudo ./traced -Ip path.conf -i eth0 -o eth1 -d 00:00:00:00:00:01
in most of the cases, the mac 00:00:00:00:00:01 should be the mac of router (so the ICMP messages are forwarded back to the sender). note that input and output interface can be the same interface.
to test this, either configure port mirror to send traffic to the box, or setup some sort of rules to route low-TTL packets to the box.
just git clone, install bison and flex, then run make in the repo root.