Run on a pcap (not pcap-ng) dump of Pokémon X/Y traffic. Outputs formatted output (using SGR sequences); make sure you use a relatively modern terminal.
make ./xydec <dump.pcap | less -r
to use like instacheck
I've slightly modified it to show some of the info that instacheck shows. Original code is intact and simply commented out. I haven't coded in C in a really long time and my edits may be rubbish. You can get it to show other relevant info such as moves/egg moves etc by editing xydec.c
I am using a raspberry-pi with a usb wifi stick acting as a router and capturing the packets with
dumpcap -i wlan0 -P -w - | /home/d1g1t/shinyvaluedetect/xydec
FireyFly for xydec
OmegaDonut for instacheck (pokemon/nature/etc names are taken from there along with the block permutations)