Netgear R7800: L2 between wlan devs on ath0 (5GHz) fails.

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mha
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Joined: 10 Sep 2011
Posts: 33

PostPosted: Fri Jan 04, 2019 11:28    Post subject: Netgear R7800: L2 between wlan devs on ath0 (5GHz) fails. Reply with quote
I'm running a Netgear R7800 with BS build r38159 with a VAP <=> VLAN via bridge L2 setup.

The router does not have any L3 connectivity to any interface except br0 where management occurs.

I've noticed that I from any computer connected to a ath0 (5GHz) device is unable to make TCP connections to other devices not connected via the TP cable in Port 1 on the LAN.

For instance connecting to the default gateway via TCP works great. External connections work great (router is not default gateway). Connecting to other cabled equipment on the network works great. Performance is great (475Mbit/s). Making a connection to another wireless device on the same bridge or even the router itself on the management IP (172.16.8.132) fails;

Code:

 tcpdump -i any -nnn -vvv host 172.16.8.132 and port 80
tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
11:59:12.135101 IP (tos 0x0, ttl 128, id 19677, offset 0, flags [DF], proto TCP (6), length 52)
    172.16.8.155.52947 > 172.16.8.132.80: Flags [S], cksum 0xc8c6 (correct), seq 1277961929, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
11:59:12.135221 IP (tos 0x0, ttl 128, id 19677, offset 0, flags [DF], proto TCP (6), length 52)
    172.16.8.155.52947 > 172.16.8.132.80: Flags [S], cksum 0xc8c6 (correct), seq 1277961929, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
11:59:15.141796 IP (tos 0x0, ttl 128, id 19678, offset 0, flags [DF], proto TCP (6), length 52)
    172.16.8.155.52947 > 172.16.8.132.80: Flags [S], cksum 0xc8c6 (correct), seq 1277961929, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
11:59:15.141916 IP (tos 0x0, ttl 128, id 19678, offset 0, flags [DF], proto TCP (6), length 52)


Double packets recorded above as -i any will record it on both ath0 and br0.

When connected to ath0 ICMP ping packets to other WLAN devices (except for the router itself) are responded to however with an extreme latency and only some of them.

Code:

$ ping 172.16.8.200
PING 172.16.8.200 (172.16.8.200) 56(84) bytes of data.
64 bytes from 172.16.8.200: icmp_seq=7 ttl=254 time=21.5 ms
64 bytes from 172.16.8.200: icmp_seq=9 ttl=254 time=17.7 ms
64 bytes from 172.16.8.200: icmp_seq=11 ttl=254 time=16.8 ms
64 bytes from 172.16.8.200: icmp_seq=12 ttl=254 time=16.6 ms
^C
--- 172.16.8.200 ping statistics ---
12 packets transmitted, 4 received, 66% packet loss, time 11022ms
rtt min/avg/max/mdev = 16.630/18.203/21.581/2.005 ms


Now for the weird part. When I connect to the 2.4GHz corresponding VAP on the same bridge (br0) all connectivity to other WLAN devices and the management IP of the router works great.

Following is the bridge configuration;

Code:

# brctl show
bridge name   bridge id      STP enabled   interfaces
br0      8000.78d294a81f3a   yes      ath0
                     ath1
                     eth1.400
br1      8000.78d294a81f3a   yes      ath0.1
                     ath1.1
                     eth1.200
br2      8000.78d294a81f3a   yes      ath0.2
                     ath1.2
                     eth1.300
br3      8000.78d294a81f3a   yes      ath0.3
                     ath1.3
                     eth1.500


Any leads to where to troubleshoot or if this is a known issue for Atheros hardware? Tried searching for similar issues but came up short handed.

Thanks!
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mha
DD-WRT Novice


Joined: 10 Sep 2011
Posts: 33

PostPosted: Sun Feb 17, 2019 11:32    Post subject: Reply with quote
Bump. Tried troubleshooting this without success a couple of times.

Did of course check the obvious settings like AP isolation etc. No dice. Smile
mha
DD-WRT Novice


Joined: 10 Sep 2011
Posts: 33

PostPosted: Sun Feb 17, 2019 13:38    Post subject: Reply with quote
Also attempted the fix on several similar issues;

Code:
swconfig dev <port> set enable_vlan 1
swconfig dev <port> set apply
swconfig dev <port> set reset


Nomatter how I do the router's WLAN and LAN hang after the apply command. Nomatter if it's superseeded with a reset or not.
Per Yngve Berg
DD-WRT Guru


Joined: 13 Aug 2013
Posts: 6856
Location: Romerike, Norway

PostPosted: Sun Feb 17, 2019 13:55    Post subject: Reply with quote
Remember this was reported some builds ago.

I am now on Kongat 38750M. No issues so far.

http://www.desipro.de/ddwrt/K3-AC-IPQ806X/Test/

Kong owns a R7800 and he test his builds.
mha
DD-WRT Novice


Joined: 10 Sep 2011
Posts: 33

PostPosted: Sun Feb 17, 2019 14:22    Post subject: Reply with quote
Per Yngve Berg wrote:
Remember this was reported some builds ago.

I am now on Kongat 38750M. No issues so far.

http://www.desipro.de/ddwrt/K3-AC-IPQ806X/Test/

Kong owns a R7800 and he test his builds.


Thanks for the tip! Smile

I upgraded to r38750M kongat (02/14/19). Unfortunately it seems like the same. Client connected to my 5GHz network;

Code:

root@wajjfajj:~# tcpdump -i any -n host 172.16.8.131 and port 22
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
15:13:44.423266 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:13:44.423391 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:13:47.424676 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:13:47.424815 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:13:53.431549 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:13:53.431692 IP 172.16.8.155.52287 > 172.16.8.131.22: Flags [S], seq 1087030503, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0


Switching the client over to the 2.4GHz band;

Code:

oot@wajjfajj:~# tcpdump -i any -n host 172.16.8.131 and port 22
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
15:14:37.730923 IP 172.16.8.237.52293 > 172.16.8.131.22: Flags [S], seq 1168250385, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:14:37.731050 IP 172.16.8.237.52293 > 172.16.8.131.22: Flags [S], seq 1168250385, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
15:14:37.732412 ethertype IPv4, IP 172.16.8.131.22 > 172.16.8.237.52293: Flags [S.], seq 2800765590, ack 1168250386, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 5], length 0
15:14:37.732515 IP 172.16.8.131.22 > 172.16.8.237.52293: Flags [S.], seq 2800765590, ack 1168250386, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 5], length 0
15:14:37.732627 IP 172.16.8.131.22 > 172.16.8.237.52293: Flags [S.], seq 2800765590, ack 1168250386, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 5], length 0
15:14:37.734340 IP 172.16.8.237.52293 > 172.16.8.131.22: Flags [.], ack 1, win 256, length 0
15:14:37.734452 IP 172.16.8.237.52293 > 172.16.8.131.22: Flags [.], ack 1, win 256, length 0


172.16.8.131 is connected in the following way;

172.16.8.131 <-> [Switch VLAN 400] <-> [Trunk port to R7800 (VLAN200,300,400,500)] <-> [R7800 eth0 VLAN 400] <-> [br1] <-> [wl] <-> [Client]

The packet capture shows the packets both on wl0/wl1 and the bridge br0. Unfortunately I have no packet capture capability on 172.16.8.131.

Side note; the Windows laptop took several minutes fully connecting to the 5GHz SSID on the Kong build. Weird.

Any other input and/or troubleshooting points to atleast get to the bottom of where this happens would be appreciated. Smile

Thanks
Per Yngve Berg
DD-WRT Guru


Joined: 13 Aug 2013
Posts: 6856
Location: Romerike, Norway

PostPosted: Sun Feb 17, 2019 14:39    Post subject: Reply with quote
Do ath0 and ath1 have unique MAC addresses on Setup->Networking?

Can you show the swconfig commands for the VLAN setup?
mha
DD-WRT Novice


Joined: 10 Sep 2011
Posts: 33

PostPosted: Sun Feb 17, 2019 14:56    Post subject: Reply with quote
Per Yngve Berg wrote:
Do ath0 and ath1 have unique MAC addresses on Setup->Networking?


Yes;

ath0: 78:D2:94:AX:XX:3C
ath1: 78:D2:94:AX:XX:3D

Per Yngve Berg wrote:

Can you show the swconfig commands for the VLAN setup?


I guess I am lazy when setting them up, but I've configured the VLAN tags under Setup => Network on the top VLAN section.

Code:

VLAN 0 Interface eth0  Tag Number 200   Prio 0
VLAN 1 Interface eth0  Tag Number 300   Prio 0
VLAN 2 Interface eth0  Tag Number 400   Prio 0
VLAN 3 Interface eth0  Tag Number 500   Prio 0
VLAN 4 Interface eth0  Tag Number 403   Prio 0


Guess they end up in NVRAM and is configured during boot via swconfig / vconfig?

I've also moved the VLANs off eth1 (seems to be the internal 4-port switch) to the WAN port (eth0) without difference. As I don't use the WAN port for anything in particular.
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