From owner-freebsd-stable@FreeBSD.ORG Tue Jun 8 18:41:10 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 36F44106564A for ; Tue, 8 Jun 2010 18:41:10 +0000 (UTC) (envelope-from ghelmer@palisadesystems.com) Received: from smtp-saas1.palisadesystems.com (smtp-saas1.palisadesystems.com [216.81.161.161]) by mx1.freebsd.org (Postfix) with ESMTP id 7A0918FC15 for ; Tue, 8 Jun 2010 18:41:08 +0000 (UTC) Received: from [172.16.2.94] (localhost.palisadesystems.com [127.0.0.1]) by smtp-saas1.palisadesystems.com (8.14.3/8.14.3) with ESMTP id o58IesQj050537; Tue, 8 Jun 2010 13:40:54 -0500 (CDT) (envelope-from ghelmer@palisadesystems.com) Mime-Version: 1.0 (Apple Message framework v1078) Content-Type: text/plain; charset=us-ascii From: Guy Helmer In-Reply-To: <4C0E8C59.5010202@earthlink.net> Date: Tue, 8 Jun 2010 13:40:53 -0500 Content-Transfer-Encoding: quoted-printable Message-Id: <8C598A97-0F1E-44A1-BAFE-48927C143553@palisadesystems.com> References: <4C0E81D7.8020209@earthlink.net> <4C0E8C59.5010202@earthlink.net> To: sclark46@earthlink.net X-Mailer: Apple Mail (2.1078) X-PacketSure-Scanned: Yes Cc: bms@freebsd.org, FreeBSD Stable Subject: Re: FreeBSD eats 169.254.x.x addressed packets X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jun 2010 18:41:10 -0000 On Jun 8, 2010, at 1:30 PM, Stephen Clark wrote: > On 06/08/2010 02:21 PM, Guy Helmer wrote: >> On Jun 8, 2010, at 12:45 PM, Stephen Clark wrote: >>=20 >>> Hi, >>>=20 >>> Why does FreeBSD 6.3 eat 169.254.x.x addressed packet when >>> 4.9 didn't? >>>=20 >>> ***** 6.3 ***** >>> $ sudo ipfstat -nio >>> empty list for ipfilter(out) >>> empty list for ipfilter(in) >>> Z2984:~ >>> $ ifconfig rl0 >>> rl0: flags=3D8843 mtu 1500 >>> options=3D8 >>> inet 192.168.129.1 netmask 0xffffff00 broadcast = 192.168.129.255 >>> inet 169.254.1.1 netmask 0xffff0000 broadcast 169.254.255.255 >>> ether 00:30:18:ae:7c:77 >>> media: Ethernet autoselect (100baseTX) >>> status: active >>> Z2984:~ >>> $ ping 169.254.1.1 >>> PING 169.254.1.1 (169.254.1.1): 56 data bytes >>> ^C >>> --- 169.254.1.1 ping statistics --- >>> 4 packets transmitted, 0 packets received, 100% packet loss >>> Z2984:~ >>> $ uname -a >>> FreeBSD Z2984.netwolves.com 6.3-RELEASE-p15 FreeBSD 6.3-RELEASE-p15 = #17: Fri Apr 16 12:51:57 EST 2010 >>>=20 >>> **** 4.9 ***** >>> FreeBSD H101494.com 4.9-STABLE FreeBSD 4.9-STABLE #59: Thu Mar 30 = 13:42:10 EST 2006 root@A1234.com:/mnt2/src/sys/compile/ i386 >>> H101494# ipf -Fa >>> H101494# ipfstat -nio >>> empty list for ipfilter(out) >>> empty list for ipfilter(in) >>> H101494# ifconfig rl0 >>> rl0: flags=3D8843 mtu 1500 >>> inet 10.254.151.1 netmask 0xffffff00 broadcast 10.254.151.255 >>> inet 10.255.3.30 netmask 0xffffffff broadcast 10.255.3.30 >>> inet 10.255.4.30 netmask 0xffffffff broadcast 10.255.4.30 >>> inet 169.254.202.1 netmask 0xffff0000 broadcast = 169.254.255.255 >>> ether 00:30:18:a3:49:b5 >>> media: Ethernet autoselect (none) >>> status: no carrier >>> H101494# ping 169.254.202.1 >>> PING 169.254.202.1 (169.254.202.1): 56 data bytes >>> 64 bytes from 169.254.202.1: icmp_seq=3D0 ttl=3D64 time=3D0.052 ms >>> 64 bytes from 169.254.202.1: icmp_seq=3D1 ttl=3D64 time=3D0.080 ms >>> 64 bytes from 169.254.202.1: icmp_seq=3D2 ttl=3D64 time=3D0.081 ms >>> ^C >>> --- 169.254.202.1 ping statistics --- >>> 3 packets transmitted, 3 packets received, 0% packet loss >>> round-trip min/avg/max/stddev =3D 0.052/0.071/0.081/0.013 ms >>>=20 >>>=20 >>=20 >>=20 >> That was a feature added to sys/netinet/in.c and ip_input.c back in = 2007 to obey RFC 3927 not to output datagrams destined for = 169.254.0.0/16. >>=20 >> On a system that needed to be able to send datagrams to = 169.254.0.0/16 addresses, I wrote this patch to add a sysctl knob = net.inet.fwd_link_local to dynamically allow a system to send those = datagrams: >>=20 >>=20 >> Index: in.c >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >> RCS file: /home/ncvs/src/sys/netinet/in.c,v >> retrieving revision 1.102.2.4.2.1 >> diff -u -r1.102.2.4.2.1 in.c >> --- in.c 15 Apr 2009 03:14:26 -0000 1.102.2.4.2.1 >> +++ in.c 29 Jul 2009 15:10:42 -0000 >> @@ -67,6 +67,9 @@ >> struct in_ifaddr *, struct sockaddr_in *, int); >> static void in_purgemaddrs(struct ifnet *); >>=20 >> +int ip_fwdlinklocal =3D 0; >> +SYSCTL_INT(_net_inet_ip, OID_AUTO, fwd_link_local, CTLFLAG_RW, >> + &ip_fwdlinklocal, 0, "Forward link-local addresses"); >> static int subnetsarelocal =3D 0; >> SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW, >> &subnetsarelocal, 0, "Treat all subnets as directly connected"); >> @@ -129,7 +132,8 @@ >> register u_long i =3D ntohl(in.s_addr); >> register u_long net; >>=20 >> - if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i) || IN_LINKLOCAL(i)) >> + if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i) || >> + (!ip_fwdlinklocal&& IN_LINKLOCAL(i))) >> return (0); >> if (IN_CLASSA(i)) { >> net =3D i& IN_CLASSA_NET; >> Index: ip_input.c >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >> RCS file: /home/ncvs/src/sys/netinet/ip_input.c,v >> retrieving revision 1.332.2.5.2.1 >> diff -u -r1.332.2.5.2.1 ip_input.c >> --- ip_input.c 15 Apr 2009 03:14:26 -0000 1.332.2.5.2.1 >> +++ ip_input.c 29 Jul 2009 15:10:44 -0000 >> @@ -134,6 +134,7 @@ >> static struct ifqueue ipintrq; >> static int ipqmaxlen =3D IFQ_MAXLEN; >>=20 >> +extern int ip_fwdlinklocal; >> extern struct domain inetdomain; >> extern struct protosw inetsw[]; >> u_char ip_protox[IPPROTO_MAX]; >> @@ -532,7 +533,7 @@ >> } >> } >> /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ >> - if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { >> + if (!ip_fwdlinklocal&& IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) = { >> ipstat.ips_cantforward++; >> m_freem(m); >> return; >>=20 >>=20 > Hmmm... how is not responding to pings associated with forwarding? >=20 My previous understanding was that RFC 3927 did not allow transmitting = datagrams involving the 169.254.0.0/16 link-local prefix; now that I've = looked over the RFC more closely, I'm not sure that is the case. I have cc'ed Bruce Simpson on this message in hopes that he can shed = some light on this. I believe he committed the change that disallowed = transmitting from 169.254.0.0/16 addresses. Guy