Python Sockets breaks Wifi between two OpenWRT machines

Installing and Using OpenWrt Network and Wireless Configuration
1

I'm trying to programmatically make two OpenWRT machines connect via a dynamically configured WiFi network using basic sockets with Python. Essentially, I have a host machine which sets up a hidden AP network. The "client" machine knows the credentials to this network, and successfully associates by calling UCI commands from with a python script. It then is expected to connect to the Host machine's socket, and then exchange a few bytes of data. However, when calling "connect_ex" on the client side, the clients networking seems to entirely break! I get error code 128 as a return from the connect method. Afterwards, the client is no longer associated with the host's network. The client gets these messages right after attempting to connect:

[ 1499.604265] br-lan: port 2(wlan0-1) entered blocking state
[ 1499.615222] br-lan: port 2(wlan0-1) entered disabled state
[ 1499.626522] device wlan0-1 entered promiscuous mode
[ 1499.636407] br-lan: port 2(wlan0-1) entered blocking state
[ 1499.647318] br-lan: port 2(wlan0-1) entered forwarding state
[ 1499.660898] br-lan: port 2(wlan0-1) entered disabled state

Strangely, the only way to fix the broken connection is to either do "wifi down; wifi up" on the host machine OR to power cycle the client machine.

Before running the script, I made sure the two were actually associated. Both machines can ping each other, the client knows the correct IP of the host (which acts as a gateway in this case), and that client is getting assigned an IP by the DHCP server on host. The firewall on the host side also has a specific rule which allows this traffic.

Even stranger, I tried creating the socket connection manually using the python interpreter. Of course, this omits almost all of the dynamic UCI configuration my script is performing before making the connection. This strategy seems to work fine!

Here's some of the network related files on the host:
Firewall file:

config defaults
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'

config zone
        option name 'lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        list network 'lan'

config zone
        option name 'wan'
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'
        list network 'wan'
        list network 'wan6'
        list network 'wwan'

config zone
        option name 'vlan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        list network 'vlan'

config rule
        option name 'Allow Server'
        option src 'vlan'
        option proto 'tcp'
        option dest_port '25565'
        option target 'ACCEPT'

config forwarding
        option src 'lan'
        option dest 'wan'


config rule
        option name 'Allow-DHCP-Renew'
        option src 'wan'
        option proto 'udp'
        option dest_port '68'
        option target 'ACCEPT'
        option family 'ipv4'

config rule
        option name 'Allow-Ping'
        option src 'wan'
        option proto 'icmp'
        option icmp_type 'echo-request'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-IGMP'
        option src 'wan'
        option proto 'igmp'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-DHCPv6'
        option src 'wan'
        option proto 'udp'
        option src_ip 'fc00::/6'
        option dest_ip 'fc00::/6'
        option dest_port '546'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-MLD'
        option src 'wan'
        option proto 'icmp'
        option src_ip 'fe80::/10'
        list icmp_type '130/0'
        list icmp_type '131/0'
        list icmp_type '132/0'
        list icmp_type '143/0'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Input'
        option src 'wan'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        list icmp_type 'router-solicitation'
        list icmp_type 'neighbour-solicitation'
        list icmp_type 'router-advertisement'
        list icmp_type 'neighbour-advertisement'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Forward'
        option src 'wan'
        option dest '*'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'

config rule
        option name 'Support-UDP-Traceroute'
        option src 'wan'
        option dest_port '33434:33689'
        option proto 'udp'
        option family 'ipv4'
        option target 'REJECT'
        option enabled 'false'

config include
        option path '/etc/firewall.user'

DHCP file

config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option nonwildcard '1'
        option localservice '1'
        option ednspacket_max '1232'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        option ra_slaac '1'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'

config dhcp 'vlan'
        option interface 'vlan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'

Network file:

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fd37:8453:da23::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'

config device
        option name 'br-vlan'
        option type 'bridge'
        list ports 'eth0.3'

config interface 'vlan'
        option device 'br-vlan'
        option proto 'static'
        option ipaddr '192.168.2.1'
        option netmask '255.255.255.0'

config device
        option name 'eth0.2'
        option macaddr '0c:cf:89:6f:9b:f8'

config interface 'wan'
        option device 'eth0.2'
        option proto 'dhcp'

config interface 'wan6'
        option device 'eth0.2'
        option proto 'dhcpv6'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '1'

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '1 2 3 4 6t'

config switch_vlan
        option device 'switch0'
        option vlan '2'
        option ports '0 6t'

config interface 'wwan'
        option proto 'dhcp'

Wireless file:

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/10300000.wmac'
        option channel '1'
        option band '2g'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'dashboard'
        option device 'radio0'
        option network 'vlan'
        option mode 'ap'
        option encryption 'none'
        option ssid 'yet another network im hosting'
        option disabled '0'

config wifi-iface 'provisioning'
        option device 'radio0'
        option network 'vlan'
        option mode 'ap'
        option ssid 'network client is connecting to'
        option encryption 'psk2'
        option key 'password'
        option hidden '1'
        option disabled '0'

config wifi-iface 'real'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option encryption 'psk2'
        option hidden '1'
        option disabled '0'
        option ssid 'another network im hosting'
        option key 'password'

config wifi-iface 'client'
        option device 'radio0'
        option network 'wwan'
        option mode 'sta'
        option disabled '0'
        option ssid 'internet for the host'
        option encryption 'psk2'
        option key 'the password'

Now here's the version of those on the client:
DHCP:

config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option nonwildcard '1'
        option localservice '1'
        option ednspacket_max '1232'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        option ra_slaac '1'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'

config dhcp 'vlan'
        option interface 'vlan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'

Firewall:
(A lot of these files are similar for the reason that I intend for the "client - host" relationship to be entirely and easily reversible, programmatically)

config defaults
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'

config zone
        option name 'lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        list network 'lan'

config zone
        option name 'wan'
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'
        list network 'wan'
        list network 'wan6'
        list network 'wwan'

config zone
        option name 'vlan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'REJECT'
        list network 'vlan'

config rule
        option name 'Allow Provisioning Server'
        option src 'vlan'
        option proto 'tcp'
        option dest_port '25565'
        option target 'ACCEPT'

config forwarding
        option src 'lan'
        option dest 'wan'

config rule
        option name 'Allow-DHCP-Renew'
        option src 'wan'
        option proto 'udp'
        option dest_port '68'
        option target 'ACCEPT'
        option family 'ipv4'

config rule
        option name 'Allow-Ping'
        option src 'wan'
        option proto 'icmp'
        option icmp_type 'echo-request'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-IGMP'
        option src 'wan'
        option proto 'igmp'
        option family 'ipv4'
        option target 'ACCEPT'

config rule
        option name 'Allow-DHCPv6'
        option src 'wan'
        option proto 'udp'
        option src_ip 'fc00::/6'
        option dest_ip 'fc00::/6'
        option dest_port '546'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-MLD'
        option src 'wan'
        option proto 'icmp'
        option src_ip 'fe80::/10'
        list icmp_type '130/0'
        list icmp_type '131/0'
        list icmp_type '132/0'
        list icmp_type '143/0'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Input'
        option src 'wan'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        list icmp_type 'router-solicitation'
        list icmp_type 'neighbour-solicitation'
        list icmp_type 'router-advertisement'
        list icmp_type 'neighbour-advertisement'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Forward'
        option src 'wan'
        option dest '*'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'

config rule
        option name 'Support-UDP-Traceroute'
        option src 'wan'
        option dest_port '33434:33689'
        option proto 'udp'
        option family 'ipv4'
        option target 'REJECT'
        option enabled 'false'

config include
        option path '/etc/firewall.user'

Network file:

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fd37:8453:da23::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option ipaddr '192.168.3.1'

config device
        option name 'br-vlan'
        option type 'bridge'
        list ports 'eth0.3'

config interface 'vlan'
        option device 'br-vlan'
        option proto 'static'
        option netmask '255.255.255.0'
        option ipaddr '192.168.4.1'

config device
        option name 'eth0.2'
        option macaddr '0c:cf:89:6f:9b:f8'

config interface 'wan'
        option device 'eth0.2'
        option proto 'dhcp'

config interface 'wan6'
        option device 'eth0.2'
        option proto 'dhcpv6

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '1'

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '1 2 3 4 6t'
 
config switch_vlan
        option device 'switch0'
        option vlan '2'
        option ports '0 6t'

config interface 'wwan'
        option proto 'dhcp'

And finally, wireless file on the client:

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/10300000.wmac'
        option channel '1'
        option band '2g'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'child_connect'
        option device 'radio0'
        option network 'wwan'
        option mode 'sta'
        option encryption 'psk2'
        option disabled '0'
        option ssid 'connecting to the host'
        option key 'password'
2

Turns out I had a rouge "os.system("wifi")" in one of my scripts, which was causing weird behavior on the server side. All the openwrt networking config was fine.

3

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