Date: Sat, 09 Nov 2013 16:44:09 -0330 From: Bear <jilingshu@gmail.com> To: Rozhuk.IM@gmail.com, 'Gleb Smirnoff' <glebius@FreeBSD.org> Cc: freebsd-net@freebsd.org Subject: Re: ng_patch and 802.11Q Message-ID: <527E9791.3070301@Gmail.com> In-Reply-To: <527e4926.aa1d700a.02d7.fffff457@mx.google.com> References: <527C799D.8020208@Gmail.com> <20131108215210.GH7577@FreeBSD.org> <527DDFEA.9050001@Gmail.com> <527e4926.aa1d700a.02d7.fffff457@mx.google.com>
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Hi all, I did a test, it seems ng_ether will capture after removing VLAN tag? > sudo nghook -a em0: lower > 0000: xx xx xx xx xx xx yy yy yy yy yy yy 08 00 45 00 .9D...........E. em0 is the parent interface of all VLAN, and data sent from this interface is ALWAYS tagged. If I run tcpdump: > tcpdump -i em0 -e -n -vv > 142.162.175.108.12401 > xxx.xxx.xxx.xxx.14875: [udp sum ok] UDP, length 59 > 09:43:04.576023 xx:xx:xx:xx:xx:xx > yy:yy:yy:yy:yy:yy, ethertype 802.1Q (0x8100), length 58: vlan 35, p 0, ethertype IPv4, (tos 0x0, ttl 126, id 5184, offset 0, flags [DF], proto TCP (6), length 40) I can see the packet has VLAN tag. How can I obtain raw Ethernet frame with 802.1Q header by netgraph? If I cannot get this, it will become impossible to modify the VLAN priority field. :-( On 2013/11/9 11:09 AM, rozhuk.im@gmail.com wrote: > http://www.netlab.linkpc.net/download/software/FreeBSD/mcastbridge/mcastbr2. > sh > http://www.netlab.linkpc.net/forum/index.php?topic=796.0 > > >> It seems a good idea... Do you have some example working on ng_ether? >> The manpage of ng_ether seems no example... >> >> On 11/8/2013 6:22 PM, Gleb Smirnoff wrote: >>> On Fri, Nov 08, 2013 at 02:11:49AM -0330, Bear wrote: >>> B> Hi all, >>> B> I want to modify VLAN priority by ng_patch. After reading the >>> B> manpage of >>> B> ng_patch(http://www.freebsd.org/cgi/man.cgi?query=ng_patch) and >> the >>> B> example it given: >>> B> >>> B> > /usr/sbin/ngctl -f- <<-SEQ >>> B> > mkpeer ipfw: patch 200 in >>> B> > name ipfw:200 ttl_add >>> B> > msg ttl_add: setconfig { count=1 csum_flags=1 ops=[ \ >>> B> > { mode=2 value=3 length=1 offset=8 } ] } >>> B> > SEQ >>> B> > /sbin/ipfw add 150 netgraph 200 ip from any to >>> B> simplex.remote.net >>> B> >>> B> It seems ng_patch can only modify IP header. However, the position >>> B> of VLAN header is before IP header and after Ethernet header. How >>> B> can I modify it? >>> >>> ipfw allows you to intercept packets at IP layer. Tp modify VLAN >>> header, you need to capture them earlier. May be ng_ether(4) will >> help you. >>> > > > >
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