Enable complex network settings

[dl1com]

Description

This pull request enables the user to set up the Pluto to work in typical Hamnet network topologies. For this purpose, bridging, NAT and and iptables support have been enabled in the Kernel. For persistent configuration, the network settings are added to the config.txt architecture of the Pluto (persistent storage in uboot fw_env)

• [x] Kernel settings
• [x] Buildroot settings
• [x] Network configuration

Supported network configurations

Basestation (via USB-Ethernet-Adapter + Lease from HAMNET-Router + Static Route from HAMNET-Router to HNAP-User-Network)

[NETWORK] hostname = master ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = # dhcp-client netmask_eth = 255.255.255.0 # will be ignored, since "ipaddr_eth = " (no value -> DHCP-Client)

[HNAP_NETWORK] ipaddr_tap = 44.128.0.17 # replaces the need for "fw_setenv hnap_tap_ip" netmask_tap = 255.255.255.240 dhcp_server_first_ip_tap = 44.128.0.21 # Starts DHCP-Server starting from .21 (max .30 due to netmask_tap) dhcp_server_leastime_tap = 600 # dhcp_server_gateway_tap = 44.128.0.17 # Configuration file for "udhcpd" reads like this:

start 44.128.0.21

                                    #    interface tap0
                                    #    option subnet 255.255.255.240
                                    #    option router 44.128.0.17
                                    #    option lease 600

Client (PC via USB + DHCP-Client on HNAP-User-Network + Masquerade packets to HNAP-User-Network)

[NETWORK] hostname = client ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = # dhcp-client netmask_eth = 255.255.255.0 # will be ignored, since "ipaddr_eth = " (no value -> DHCP-Client)

[HNAP_NETWORK] ipaddr_tap = # udhcpc running on "tap0" netmask_tap = 255.255.255.0 # see section [USB_ETHERNET]; I guess it is not required if ipaddr_eth/tap is empty

[NAT] nat_interface = HNAP_NETWORK # translates to "iptables -t nat -A POSTROUTING -o tap0 -j MASQUERADE"

---

Basestation (via USB-Ethernet-Adapter + Bridge USB_ETHERNET / HNAP_NETWORK + Lease from HAMNET-Router)

[BRIDGE] master_interface = USB_ETHERNET slave_interface_1 = HNAP_NETWORK

[NETWORK] hostname = master ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = # dhcp-client netmask_eth = 255.255.255.0 # will be ignored, since "ipaddr_eth = " (no value -> DHCP-Client)

[HNAP_NETWORK] ipaddr_tap = 44.128.0.17 # since HNAP_NETWORK is a "slave_interface" all settings are ignored netmask_tap = 255.255.255.240 # since HNAP_NETWORK is a "slave_interface" all settings are ignored

---

Basestation (via USB-Ethernet-Adapter + Bridge USB_ETHERNET / HNAP_NETWORK + static IP)

[BRIDGE] master_interface = USB_ETHERNET slave_interface = HNAP_NETWORK

[NETWORK] hostname = master ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = 44.128.0.2 netmask_eth = 255.255.255.240 gateway_eth = 44.128.0.1 # set defaultroute

[HNAP_NETWORK] ipaddr_tap = 44.128.0.17 # since HNAP_NETWORK is a "slave_interface" all settings are ignored netmask_tap = 255.255.255.240 # since HNAP_NETWORK is a "slave_interface" all settings are ignored

---

Client (Integration into HomeLAN via USB-Ethernet-Adapter + DHCP-Client on HNAP-User-Network + Masquerade packets to HNAP-User-Network)

--> same as "normal client configuration (see first example)

[NETWORK] hostname = client ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = # dhcp-client netmask_eth = 255.255.255.0 # will be ignored, since "ipaddr_eth = " (no value -> DHCP-Client)

[HNAP_NETWORK] ipaddr_tap = # udhcpc running on "tap0" netmask_tap = 255.255.255.0 # see section [USB_ETHERNET]; I guess it is not required if ipaddr_eth/tap is empty

[NAT] nat_interface = HNAP_NETWORK # translates to "iptables -t nat -A POSTROUTING -o tap0 -j MASQUERADE"

---

Client (Integration into HomeLAN via USB-Ethernet-Adapter to Mikrotik-Router + Bridge USB_ETHERNET / HNAP_NETWORK + DHCP-Client on HNAP-User-Network)

[BRIDGE] master_interface = USB_ETHERNET slave_interface_1 = HNAP_NETWORK

[NETWORK] hostname = client ipaddr = 192.168.2.1 netmask = 255.255.255.0 dhcp_server_first_ip = 192.168.2.10 # or: "ipaddr_host = 192.168.2.10" dhcp_server_leasetime = 600 # 10 minutes lease time dhcp_server_gateway = 192.168.2.1 # Usually "dhcp_server_gateway" equals to "ipaddr" (for me it is OK to type the IP twice)

[USB_ETHERNET] ipaddr_eth = # udhcpc running on Bridge (master_interface) netmask_eth = 255.255.255.0

[HNAP_NETWORK] ipaddr_tap = # nothing - slave client netmask_tap = 255.255.255.0 #

[dl1com]

Current default settings:

[NETWORK]
hostname = pluto
ipaddr = 192.168.2.1
netmask = 255.255.255.0
dhcp_server_pool_start = 192.168.2.10
dhcp_server_leasetime = 600
dhcp_server_gateway = 192.168.2.1

[WLAN]
ssid_wlan = 
pwd_wlan = 
ipaddr_wlan = 

[USB_ETHERNET]
ipaddr_eth = 
netmask_eth = 255.255.255.0

[HNAP_NETWORK]
ipaddr_tap = 
netmask_tap = 255.255.255.240
dhcp_server_pool_start_tap = 
dhcp_server_leasetime_tap = 600
dhcp_server_gateway_tap = 

[NAT]
nat_interface = HNAP_NETWORK

[BRIDGE]
master_interface = 
slave_interface_1 = 

• If ipaddr/ipaddr_tap are unset, this interface acts as a DHCP client
• If dhcp_server_pool_start/dhcp_server_pool_start_tap is set, a DHCP server is started on this interface
• In NAT and BRIDGE, these names can be used: NETWORK, WLAN, USB_ETHERNET, HNAP_NETWORK

[dl1com]

Current default settings:

[NETWORK]
hostname = pluto
ipaddr = 192.168.2.1
netmask = 255.255.255.0
dhcp_server_pool_start = 192.168.2.10
dhcp_server_leasetime = 600
dhcp_server_gateway = 192.168.2.1
dhcp_server_dns = 192.168.2.1

[WLAN]
ssid_wlan = 
pwd_wlan = 
ipaddr_wlan = 

[USB_ETHERNET]
ipaddr_eth = 
netmask_eth = 255.255.255.0

[HNAP_NETWORK]
ipaddr_tap = 
netmask_tap = 255.255.255.240
dhcp_server_pool_start_tap = 
dhcp_server_leasetime_tap = 600
dhcp_server_gateway_tap = 
dhcp_server_dns_tap = 

[NAT]
nat_interface = HNAP_NETWORK

[BRIDGE]
bridge_master_interface = 
bridge_slave_interface_1 = 

• NETWORK interface works only with static IP, no DHCP client
• If ipaddr_eth/ipaddr_tap are unset, this interface acts as a DHCP client
• If dhcp_server_pool_start/dhcp_server_pool_start_tap is set, a DHCP server is started on this interface
• In NAT, these names can be used: NETWORK, WLAN, USB_ETHERNET, HNAP_NETWORK or NONE
• In BRIDGE, these names can be used: NETWORK, WLAN, USB_ETHERNET, HNAP_NETWORK or leave it empty

Known issues:

• udhcpc on HNAP_NETWORK tries discovery only 3 times, then goes idle. We'll add a script to continuously send discoveries until we have a lease

[dl1com]

After some discussion with @dg8ngn, we'll do some changes to optimize bridge config:

• Get rid of the [NAT] section and move the NAT decision inside the interfaces:

[NETWORK]
nat = yes       --> "pre-up iptables -t nat -A POSTROUTING -o usb -j MASQUERADE"
[WLAN]
nat_wlan = yes  --> "pre-up iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE"
[USB_ETHERNET]
nat_eth = yes   --> "pre-up iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE"
[HNAP_NETWORK]
nat_tap = yes   --> "pre-up iptables -t nat -A POSTROUTING -o tap0 -j MASQUERADE"

• Bridging
  • search for "bridge_x = master"
  • Use configuration of "bridge_x" for "br0" in /etc/network/interfaces
  • if there it has NAT enabled --> "pre-up iptables -t nat -A POSTROUTING -o br0 -j MASQUERADE"
  • if "bridge_tap" != no, then "pre-up tunctl -t tap0" as first line in br0
  • next line for "br0": "pre-up brctl addbr br0"
  • search for "bridge_x = slave" (may exist multiple times)
  • add "pre-up brctl addif br0 "
  • add "pre-up brctl addif br0 <interface slave 1>"
  • add "pre-up brctl addif br0 "

[dl1com]

Current config.txt default settings:

[NETWORK]
hostname = pluto
ipaddr = 192.168.2.1
netmask = 255.255.255.0
nat = 
bridge = 
dhcp_server_pool_start = 192.168.2.10
dhcp_server_leasetime = 600
dhcp_server_gateway = 192.168.2.1
dhcp_server_dns = 192.168.2.1

[WLAN]
ssid_wlan = 
pwd_wlan = 
ipaddr_wlan = 
nat_wlan = 
bridge_wlan = 

[USB_ETHERNET]
ipaddr_eth = 
netmask_eth = 255.255.255.0
nat_eth = 
bridge_eth = 
dhcp_server_pool_start_eth = 
dhcp_server_leasetime_eth = 600
dhcp_server_gateway_eth = 
dhcp_server_dns_eth = 

[HNAP_NETWORK]
ipaddr_tap = 
netmask_tap = 255.255.255.240
nat_tap = 
bridge_tap = 
dhcp_server_pool_start_tap = 
dhcp_server_leasetime_tap = 600
dhcp_server_gateway_tap = 
dhcp_server_dns_tap = 

• NETWORK interface works only with static IP, no DHCP client
• If ipaddr_eth/ipaddr_tap are unset, this interface acts as a DHCP client
• If dhcp_server_pool_start/dhcp_server_pool_start_eth/dhcp_server_pool_start_tap is set, a DHCP server is started on this interface
• If nat_x is set to yes, this interfaces gets a NAT rule in iptables
• Bridging:
  • To define a bridge br0, one interface has to be set to bridge_x = master
  • The bridge will inherit the settings from the master interface (Static&Dynamic IP setting, DHCP Server, NAT)
  • To add interfaces to this bridge, set bridge_x = slave
  • If bridge_x is neither set to master or slave, it will not be affected by bridging

Bridging Example:

config.txt:

[NETWORK]
hostname = pluto
ipaddr = 192.168.2.1
netmask = 255.255.255.0
nat =
bridge = 
dhcp_server_pool_start = 192.168.2.10
dhcp_server_leasetime = 600
dhcp_server_gateway = 192.168.2.1
dhcp_server_dns = 192.168.2.1

[WLAN]
ssid_wlan = 
pwd_wlan = 
ipaddr_wlan = 
nat_wlan = 
bridge_wlan = 

[USB_ETHERNET]
ipaddr_eth = 
netmask_eth = 255.255.255.0
nat_eth = 
bridge_eth = master
dhcp_server_pool_start_eth = 
dhcp_server_leasetime_eth = 600
dhcp_server_gateway_eth = 
dhcp_server_dns_eth = 

[HNAP_NETWORK]
ipaddr_tap = 
netmask_tap = 255.255.255.240
nat_tap = 
bridge_tap = slave
dhcp_server_pool_start_tap = 
dhcp_server_leasetime_tap = 600
dhcp_server_gateway_tap = 
dhcp_server_dns_tap = 

-> /etc/network/interfaces:

auto lo
iface lo inet loopback

auto usb0
iface usb0 inet static
        address 192.168.2.1
        netmask 255.255.255.0

auto br0
iface br0 inet dhcp
    pre-up tunctl -t tap0
    pre-up brctl addbr br0
    pre-up brctl addif br0 eth0
    pre-up brctl addif br0 tap0

Known issues:

• udhcpc tries discovery only 3 times, then goes idle. This might especially become an issue on tap0 (HNAP_NETWORK) We'll should add a script to continuously send discoveries until we have a lease
• config.txt is somewhat cluttered by our additional paramters (e.g. DHCP server) if they are unused - shall we omit them if currently not set or leave them for documentary purposes?