This program crafts an Ethernet frame which transport an UDP datagram and then sends it through a chosen Ethernet interface. It allows to spoof both IP src address and src MAC address.

An ethernet link. To configure it:

1 - Directly connect 2 computers through an ethernet cable

2 - Assign to both computers ethernet interfaces an IP address in the same subnet

ifconfig eth0 10.0.0.1 netmask 255.255.255.0 up.

ifconfig enp0s3 10.0.0.2 netmask 255.255.255.0 up.

usage: craft srcip dstip srcmac dstmac srcport dstport ethif data

On one computer listen udp connections on 5555 port

nc -ulvvp 5555

On the other

gcc udpcrafter.c -o udpcrafter

./udpcrafter 10.0.0.8 10.0.0.2 aa:bb:cc:dd:ee:ff a2:bd:ee:a9:d7:ff 4444 5555 eth0 hello

You can check the content of the fields using Wireshark