[LEDE-DEV] [PATCH] BT Home Hub 5A: configure Red Ethernet as DMZ interface (FS#490) and fix Red Ethernet switch port (FS#390)

Mauro Mozzarelli mauro at ezplanet.net
Thu Feb 16 09:37:41 PST 2017


I have just come across a weird side effect of the following change. 
With the patch applied it is no longer possible to communicate via the 
red Ethernet between 2 BT Home Hub 5, but communications are fine 
between a HH5 and any other device (??).

diff --git a/target/linux/lantiq/dts/BTHOMEHUBV5A.dts 
index 7f19e52..59b6cee 100644
--- a/target/linux/lantiq/dts/BTHOMEHUBV5A.dts
+++ b/target/linux/lantiq/dts/BTHOMEHUBV5A.dts
@@ -244,15 +244,6 @@
             phy-mode = "gmii";
             phy-handle = <&phy13>;
-   };
-   wan: interface at 1 {
-       compatible = "lantiq,xrx200-pdi";
-       #address-cells = <1>;
-       #size-cells = <0>;
-       reg = <1>;
-       lantiq,wan;
         ethernet at 5 {
             compatible = "lantiq,xrx200-pdi-port";
             reg = <5>;


With the above patch applied (and changing board.json to include port 5) 
the red Ethernet appears as eth0.2

SCENARIO with above patch applied:
red Ethernet appears as eth0.2 and assigned an IP

2 x bt (BTHomeHub5) routers (a and b) plus other devices (od)
bt(a), bt(b) and od have eth0.2 on the same subnet

ping bt(a) --> bt(b) no response (tcpdump shows arp request from bt(a) 
mac address and no arp response from bt(b)
ping bt(b) --> bt(a) as above
ping bt(a or b) --> od  OK
ping od --> bt(a or b) OK

SCENARIO without above patch applied
red Ethernet as eth1.2 and bridged (it does not work if I do not create 
a bridge and assign eth1.2 to the bridge, but we knew this)

ping bt(a) --> bt(b) OK
ping bt(b) --> bt(a) OK
ping bt(a or b) --> od  OK
ping od --> bt(a or b) OK


On 13/02/17 07:27, Mathias Kresin wrote:
> 12.02.2017 17:40, Mauro Mozzarelli:
>> You are correct that the name does not matter, however if we have
>> routers already configured to associate the xDSL or Ethernet to WAN,
>> when we flash the new firmware we will have to reconfigure them to
>> rename the device. This is all good if the routers are physically there,
>> but when the routers are in remote unmanaged locations (like I have) it
>> becomes a problem. Renaming the interface is a small thing, but it will
>> impact many end users. I advocate to maintain WAN for xDSL out of my use
>> case interest and also because personally I think an xDSL is truly a WAN
>> interface whilst an Ethernet can be anything.
> Please keep in mind that your existing config is not touched and the 
> wan network still exists with my patches applied. I fail to see how it 
> should break existing xDSL configs.
> But you are right, the ethernet wan config will most likely not work 
> any longer for people who managed to workaround all the outlined 
> issues. But the same applies to your patch, since you are moving the 
> ethernet wan from eth1 to eth0 as well. Lets hope that only the 
> minority of the uses managed to configure a working ethernet wan.
> Mathias
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Mauro Mozzarelli
eMail: mauro at ezplanet.net
Phone: +44 7941 727378

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