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From: Jim Fleming <JimFleming@unety.net>
To: "current@FreeBSD.org" <current@FreeBSD.org>,
        "'Poul-Henning Kamp'"
	 <phk@critter.tfs.com>
Cc: Jim Fleming <JimFleming@unety.net>
Subject: RE: SLIP: Check IP Version (please test)
Date: Tue, 23 Apr 1996 15:17:57 -0500
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On Tuesday, April 23, 1996 3:05 PM, Poul-Henning Kamp[SMTP:phk@critter.tfs.com] wrote:
@
@Somebody running slip with header compression please test this patch.
@
@Poul-Henning
@
@> I am starting to develop a substantialliy modified version of the IP protocol
@.
@> As specified in the IP protocol the ip_v (IP Version) field of the IP header
@> should be set to 4. (see /usr/src/sys/netinet/ip.h)
@> 
@> It is not desirable for new versions of IP to "break" existing code. I have n
@ot
@> provide this but in studying the SLIP code I see that there is never really
@> a check done to see of the IP header is of version 4.
@
@Index: if_sl.c
@===================================================================
@RCS file: /home/ncvs/src/sys/net/if_sl.c,v
@retrieving revision 1.37
@diff -u -r1.37 if_sl.c
@--- if_sl.c	1996/04/07 17:39:09	1.37
@+++ if_sl.c	1996/04/23 20:03:53
@@@ -561,7 +561,8 @@
@ 			} while (m1 = m1->m_next);
@ 		}
@ #endif
@-		if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
@+		if ((ip = mtod(m, struct ip *))->ip_v == IPVERSION) &&
@+		    (ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
@ 			if (sc->sc_if.if_flags & SC_COMPRESS)
@ 				*mtod(m, u_char *) |= sl_compress_tcp(m, ip,
@ 				    &sc->sc_comp, 1);
@--
@Poul-Henning Kamp           | phk@FreeBSD.ORG       FreeBSD Core-team.
@http://www.freebsd.org/~phk | phk@login.dknet.dk    Private mailbox.
@whois: [PHK]                | phk@ref.tfs.com       TRW Financial Systems, Inc.
@Future will arrive by its own means, progress not so.
@
@

It looks good here....now SLIP will not compress our IPv8 IP headers...:-)

--
Jim Fleming
UNETY Systems, Inc.
Naperville, IL 60563

e-mail: JimFleming@unety.net