From: Andrew Lunn <andrew@lunn.ch>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: "Pali Rohár" <pali.rohar@gmail.com>,
"Ido Schimmel" <idosch@idosch.org>,
netdev@vger.kernel.org, "Jiri Pirko" <jiri@resnulli.us>,
"Ivan Vecera" <ivecera@redhat.com>,
"Vivien Didelot" <vivien.didelot@gmail.com>
Subject: Re: [RFC 0/3] VLANs, DSA switches and multiple bridges
Date: Thu, 2 Jan 2020 13:54:17 +0100 [thread overview]
Message-ID: <20200102125417.GA22789@lunn.ch> (raw)
In-Reply-To: <20200101173014.GZ25745@shell.armlinux.org.uk>
> # tcpdump -enXXi $host_dsa_interface
>
> Here's an example ping packet received over the vlan with the above
> configuration, captured from the host DSA interface (ether mac
> addresses obfuscated):
>
> 0x0000: DDDD DDDD DDDD SSSS SSSS SSSS dada 0000 .PC.....[h:.....
> ^^^^^^^^^
> 0x0010: c020 0000 8100 0080 0800 4500 0054 ec40 ..........E..T.@
> ^^^^^^^^^ ^^^^^^^^^ ^^^^
> 0x0020: 4000 4001 c314 c0a8 0502 c0a8 0501 0800 @.@.............
> 0x0030: 8784 0c85 0001 32c8 0c5e 0000 0000 59fc ......2..^....Y.
> 0x0040: 0c00 0000 0000 1011 1213 1415 1617 1819 ................
> 0x0050: 1a1b 1c1d 1e1f 2021 2223 2425 2627 2829 .......!"#$%&'()
> 0x0060: 2a2b 2c2d 2e2f 3031 3233 3435 3637 *+,-./01234567
>
> dada 0000 c020 0000 - EDSA tag
> 8100 0080 - VLAN ethertype, vlan id
> 0800 - IPv4 ethertype, and what follows is the ipv4
> packet.
>
> That way it would be possible to know whether the DSA switch is
> forwarding the packets, and in what manner it's forwarding them.
Hi Russell
Try upgrading your tcpdump and pcap library. It now understands DSA
headers, will dump them in a semi human readable way, and also the
rest of the frame.
Andrew
prev parent reply other threads:[~2020-01-02 12:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-22 19:22 [RFC 0/3] VLANs, DSA switches and multiple bridges Russell King - ARM Linux admin
2019-12-22 19:24 ` [RFC 1/3] net: switchdev: do not propagate bridge updates across bridges Russell King
2019-12-24 8:39 ` Ido Schimmel
2019-12-25 7:41 ` Ido Schimmel
2019-12-22 19:24 ` [RFC 2/3] net: dsa: mv88e6xxx: fix duplicate vlan warning Russell King
2019-12-23 17:49 ` Florian Fainelli
2019-12-22 19:24 ` [RFC 3/3] net: dsa: mv88e6xxx: fix vlan setup Russell King
2019-12-23 18:02 ` Florian Fainelli
2019-12-24 8:30 ` Ido Schimmel
2019-12-23 11:16 ` [RFC 0/3] VLANs, DSA switches and multiple bridges Andrew Lunn
2019-12-31 16:10 ` Pali Rohár
2019-12-31 18:06 ` Ido Schimmel
2020-01-01 1:10 ` Pali Rohár
2020-01-01 17:30 ` Russell King - ARM Linux admin
2020-01-01 18:07 ` Pali Rohár
2020-01-01 18:29 ` Russell King - ARM Linux admin
2020-01-02 4:53 ` Florian Fainelli
2020-01-02 15:40 ` Pali Rohár
2020-01-02 12:54 ` Andrew Lunn [this message]
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