For cisco IGRP priting add -DIGRP in CFLAGS.
Modified files are Makefile, interface.h, print-ip.c
New files are igrp.h and print-igrp.c
Read Charles L. Hedrick paper on IGRP (on ftp.cisco.com)

An example is :

> C% tcpdump -v -p -s 2000 ip proto 9
> 14:37:32.99 paca-gw.inria.fr > 192.93.1.255: igrp 208(ttl 2, id 0)
>   Update vers=1 edit=70 AS=774 (0 int / 14 sys / 0 ext)
>  192.54.214.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  192.54.176.0 d=20000 b=64 r=255 l=100 M=158250 mtu=1500 in 0 hops
>  192.54.174.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  192.54.175.0 d=20000 b=64 r=255 l=100 M=158250 mtu=1500 in 0 hops
>  192.33.144.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  192.33.149.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  128.16.0.0 d=167772150 b=64 r=255 l=21 M=16777215 mtu=576 in 2 hops
>  192.44.79.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  192.70.34.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  192.70.35.0 d=20000 b=64 r=255 l=100 M=158250 mtu=1500 in 0 hops
>  192.70.50.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  134.59.0.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops
>  128.86.0.0 d=167772150 b=64 r=241 l=25 M=16777215 mtu=576 in 8 hops
>  139.124.0.0 d=1000 b=10000 r=255 l=1 M=1100 mtu=1500 in 0 hops

Francis.Dupont@inria.fr Sun Apr 21 1991
