[LEDE-DEV] IPv6 link locals, vlans and bridging
Matthew McClintock
msm-oss at mcclintock.net
Fri Aug 25 07:35:19 PDT 2017
On Fri, Aug 25, 2017 at 8:16 AM, Kevin Darbyshire-Bryant
<kevin at darbyshire-bryant.me.uk> wrote:
> Here's a 'fun' one that I'm trying to work who is doing what incorrectly.
>
> For 'reasons' I have a number of tagged vlan ethernet interfaces. I also
> have a similar number of wifi interfaces. These vlan ethernet interfaces
> and wifi interfaces are bridged together in pairs.
>
> The wifi interfaces have non-unique link local addresses that appear auto
> assigned:
>
> wlan0 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:4E
> inet6 addr: fe80::62e3:27ff:feaf:9e4e/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:43577 errors:0 dropped:0 overruns:0 frame:0
> TX packets:82723 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:15588069 (14.8 MiB) TX bytes:97978594 (93.4 MiB)
>
> wlan0-1 Link encap:Ethernet HWaddr 62:E3:27:AF:9E:4E
> inet6 addr: fe80::60e3:27ff:feaf:9e4e/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15106 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 B) TX bytes:7953093 (7.5 MiB)
>
> wlan1 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:4F
> inet6 addr: fe80::62e3:27ff:feaf:9e4f/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:90 errors:0 dropped:0 overruns:0 frame:0
> TX packets:16399 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:12498 (12.2 KiB) TX bytes:8373520 (7.9 MiB)
>
> wlan1-1 Link encap:Ethernet HWaddr 62:E3:27:AF:9E:4F
> inet6 addr: fe80::60e3:27ff:feaf:9e4f/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15748 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 B) TX bytes:8266015 (7.8 MiB)
>
> The ethernet vlans mostly do not have link local addresses except eth1.3
> which is the main untagged and hence main interface (this also has a global
> address)
>
> eth1.10 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:39845 errors:0 dropped:0 overruns:0 frame:0
> TX packets:69474 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:5739889 (5.4 MiB) TX bytes:65964032 (62.9 MiB)
>
> eth1.15 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15786 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:319 (319.0 B) TX bytes:7995298 (7.6 MiB)
>
> eth1.20 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:29258 errors:0 dropped:0 overruns:0 frame:0
> TX packets:50498 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:2799288 (2.6 MiB) TX bytes:36024938 (34.3 MiB)
>
> eth1.25 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15782 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:319 (319.0 B) TX bytes:7994866 (7.6 MiB)
>
> eth1.3 Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> inet addr:192.250.219.1 Bcast:192.168.250.255 Mask:255.255.255.0
> inet6 addr: fe80::62e3:27ff:feaf:9e50/64 Scope:Link
> inet6 addr: 2a02:c7f:1250:1250::da2b:da2b/64 Scope:Global
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:8254319 errors:0 dropped:0 overruns:0 frame:0
> TX packets:5455240 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:12101826609 (11.2 GiB) TX bytes:325616404 (310.5 MiB)
>
> So far, possibly so good. The 'fun' starts with the bridge interfaces:
>
> br-wifi5_guest Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> inet addr:192.168.25.1 Bcast:192.168.25.255 Mask:255.255.255.0
> inet6 addr: 2a02:c7f:1234:bf25::da2b:da2b/64 Scope:Global
> inet6 addr: fe80::62e3:27ff:feaf:9e50/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15782 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:319 (319.0 B) TX bytes:7994866 (7.6 MiB)
>
> br-wifi5_priv Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> inet addr:192.168.20.1 Bcast:192.168.20.255 Mask:255.255.255.0
> inet6 addr: 2a02:c7f:1234:bf20::da2b:da2b/64 Scope:Global
> inet6 addr: fe80::62e3:27ff:feaf:9e50/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:72837 errors:0 dropped:0 overruns:0 frame:0
> TX packets:113739 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:17777291 (16.9 MiB) TX bytes:123549133 (117.8 MiB)
>
> br-wifi_guest Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> inet addr:192.168.15.1 Bcast:192.168.15.255 Mask:255.255.255.0
> inet6 addr: fe80::62e3:27ff:feaf:9e50/64 Scope:Link
> inet6 addr: 2a02:c7f:1234:bf15::da2b:da2b/64 Scope:Global
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:3 errors:0 dropped:0 overruns:0 frame:0
> TX packets:15786 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:319 (319.0 B) TX bytes:7995298 (7.6 MiB)
>
> br-wifi_priv Link encap:Ethernet HWaddr 60:E3:27:AF:9E:50
> inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0
> inet6 addr: fe80::62e3:27ff:feaf:9e50/64 Scope:Link
> inet6 addr: 2a02:c7f:1234:bf10::da2b:da2b/64 Scope:Global
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:39937 errors:0 dropped:0 overruns:0 frame:0
> TX packets:69501 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:5751139 (5.4 MiB) TX bytes:65973138 (62.9 MiB)
>
> You will note that they all have the same link local address. I honestly
> don't know if that's legal or not, but let's move on to the problem.
>
> I have dnsmasq listening on the bridge interfaces - it's happy doing so and
> says it's listening on the link local address (effectively the same address
> many times) all ok. It also listens on the global address. If I configure
> dns clients to use the link local address for DNS service I get no
> responses. If I configure dns clients to use the global address relevant
> for each bridge then dns responses are fine.
>
> I suspect that dnsmasq is receiving the requests but is unable to
> reply....goes to enable some logging to test that a bit later...
>
> Who is doing what incorrectly here?
Just a random bit of info, I've had dnsmasq issues with bridges until
I disabled these:
net.bridge.bridge-nf-call-ip6tables=0
net.bridge.bridge-nf-call-iptables=0
net.bridge.bridge-nf-call-arptables=0
Not sure this is your issue, but you should run tcpdump on the
interfaces and see what's going on.
-M
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