Feature request: allow integers in -y

[gpotter2]

Hello,

It would be great if the -y option (data link type) could also accept the integer values of the DLT types.

It would require a small change in

tcpdump/tcpdump.c

Lines 1823 to 1829 in c36abfe

	case 'y':
	yflag_dlt_name = optarg;
	yflag_dlt =
	pcap_datalink_name_to_val(yflag_dlt_name);
	if (yflag_dlt < 0)
	error("invalid data link type %s", yflag_dlt_name);
	break;

We play around with the numeric values of the datalinks in Scapy, (therefore we don't support -y ATM) as we use them to write pcaps, therefore it would make it easier for us to call tcpdump.

[guyharris]

You can use pcap_datalink_val_to_name() to translate a numerical value to a name, if either 1) you're writing your own Python wrapper for libpcap or 2) whatever wrapper you're using provides it.

[gpotter2]

Thanks for the tip. That works great

Thanks for your work on tcpdump & libpcap !