NetBSD Problem Report #41121

From darrenr@netbsd.org  Wed Apr  1 19:15:32 2009
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Date: Wed,  1 Apr 2009 19:15:32 +0000 (UTC)
From: darrenr@netbsd.org
Reply-To: darrenr@netbsd.org
To: gnats-bugs@gnats.NetBSD.org
Subject: <net/dlt.h> needs to be realigned with tcpdump distro
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>Number:         41121
>Category:       kern
>Synopsis:       <net/dlt.h> needs to be realigned with tcudmp disto
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 01 19:20:01 +0000 2009
>Closed-Date:    Sat Dec 06 03:16:18 +0000 2025
>Last-Modified:  Sat Dec 06 03:16:18 +0000 2025
>Originator:     Darren Reed
>Release:        NetBSD 4.0_STABLE
>Organization:
NetBSD
>Environment:


System: NetBSD homeworld.netbsd.org 4.0_STABLE NetBSD 4.0_STABLE (NBMAIL) #1: Fri Sep 5 16:31:35 UTC 2008 root@ADMIN:/usr/obj/sys/arch/i386/compile.i386/NBMAIL i386
Architecture: i386
Machine: i386
>Description:
NetBSD has defined at least two DLT types, DLT_HIPPI and DLT_HDLC
that do not appear in the upstream (tcpdump.org) bpf.h file that
lists all of the various DLTs supported by libpcap.
From our <net/dlt.h> file:

#define DLT_HIPPI       15      /* HIPPI */
#define DLT_HDLC        16      /* HDLC framing */

For all platforms aside from FreeBSD and NetBSD, libpcap has this:
#define DLT_SLIP_BSDOS  15      /* BSD/OS Serial Line IP */
#define DLT_PPP_BSDOS   16      /* BSD/OS Point-to-point Protocol */
... for which we use 13 & 14.

It is probably worthwhile taking the time to work through all of the
defines in <net/dlt.h>, bring in ones that aren't there and work with
tcpdump.org to agree on numbers for ones we have but they don't.
>How-To-Repeat:

>Fix:


>Release-Note:

>Audit-Trail:
From: Guy Harris <gharris@sonic.net>
To: "gnats-bugs@netbsd.org" <gnats-bugs@NetBSD.org>
Cc: 
Subject: Re: kern/41121
Date: Mon, 10 Nov 2025 11:03:47 -0800

 Different numerical values for the same DLT_ definition, and different =
 DLT_ definitions for the same numeric value, are no longer an issue.

 Source code should *not* use numerical DLT_ values, it should use the =
 DLT_ #defines.

 libpcap no longer writes DLT_ values in capture files; instead, there is =
 a set of LINKTYPE_ values, with platform-independent definitions, listed =
 at https://www.tcpdump.org/linktypes.html, and it maps between the =
 LINKTYPE_ values in capture files and the DLT_ values in its API.

 NetBSD's is tracking tcpdump.org's libpcap and has picked up those =
 changes.

 So nothing more needs to be done here.=

State-Changed-From-To: open->closed
State-Changed-By: lukem@NetBSD.org
State-Changed-When: Sat, 06 Dec 2025 03:16:18 +0000
State-Changed-Why:
Guy Harris mentioned this isn't a problem any more.
Comparing external/bsd/libpcap/dist/pcap/dlt.h and sys/net/dlt.h
shows they're mostly identical, with some NetBSD-specific DLT_CLASS()
related defined at the end of the file


>Unformatted:

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