Re: [RFC TCPDUMP PATCH 2/2] Add sll_ifindex into sll_header + use it to print ifname

[Guy Harris <gharris () sonic net>]

On Jul 12, 2018, at 11:33 AM, Petr Vorel <pvorel () suse cz> wrote:

> +#ifdef PCAP_SUPPORT_SLL_V2
> +     char ifname[IF_NAMESIZE];
> +     if (if_indextoname(EXTRACT_BE_U_6(sllp->sll_ifindex), ifname))
> +             ND_PRINT("IFNAME %s ", ifname);
> +#endif

What happens if you capture traffic on machine A and print it on machine B, where machines A and B have different sets 
of network interfaces?

(This is why pcapng has Interface Description Blocks - so that the list of interfaces is part of the file, so you use 
*that*, rather than the configuration of interfaces on the machine running the program reading the capture, to get 
interface names.)

Perhaps this should be done *only* for live captures, *not* for reading savefiles.
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