.. _networking_with_native_sim_eth_bridge: Ethernet bridge with native_sim board ##################################### .. contents:: :local: :depth: 2 This document describes how to set up a bridged Ethernet network between a (Linux) host and a Zephyr application running in a :ref:`native_sim ` board. This setup is useful when testing the Ethernet bridging feature that can be enabled with :kconfig:option:`CONFIG_NET_ETHERNET_BRIDGE` Kconfig option. In this setup, the net-tools configuration creates two host network interfaces ``zeth0`` and ``zeth1`` and connects them to Zephyr's :ref:`native_sim ` application. First create the host interfaces. In this example two interfaces are created. .. code-block:: console cd $ZEPHYR_BASE/../tools/net-tools ./net-setup.sh -c zeth-multiface.conf -i zeth0 -t 2 The ``-c`` tells which configuration file to use, where ``zeth-multiface.conf`` is tailored for generating multiple network interfaces in the host. The ``-i`` option tells what is the first host interface name. The ``-t`` tells how many network interfaces to create. Example output of the host interfaces: .. code-block:: console zeth0: flags=4099 mtu 1500 inet 192.0.2.2 netmask 255.255.255.255 broadcast 0.0.0.0 inet6 2001:db8::2 prefixlen 128 scopeid 0x0 inet6 fe80::200:5eff:fe00:5300 prefixlen 64 scopeid 0x20 ether 00:00:5e:00:53:00 txqueuelen 1000 (Ethernet) RX packets 33 bytes 2408 (2.4 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 49 bytes 4092 (4.0 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 zeth1: flags=4099 mtu 1500 inet 198.51.100.1 netmask 255.255.255.255 broadcast 0.0.0.0 inet6 fe80::200:5eff:fe00:5301 prefixlen 64 scopeid 0x20 inet6 2001:db8:2::1 prefixlen 128 scopeid 0x0 ether 00:00:5e:00:53:01 txqueuelen 1000 (Ethernet) RX packets 21 bytes 1340 (1.3 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 45 bytes 3916 (3.9 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 Then create a sample and enable Ethernet bridging support. In this example we create :zephyr:code-sample:`sockets-echo-server` sample application. .. code-block:: console west build -p -b native_sim -d ../build/echo-server \ samples/net/sockets/echo_server -- \ -DCONFIG_NATIVE_UART_AUTOATTACH_DEFAULT_CMD="\"gnome-terminal -- screen %s\"" \ -DCONFIG_NET_ETHERNET_BRIDGE=y \ -DCONFIG_NET_ETHERNET_BRIDGE_SHELL=y \ -DCONFIG_ETH_NATIVE_POSIX_INTERFACE_COUNT=2 \ -DCONFIG_NET_IF_MAX_IPV6_COUNT=2 \ -DCONFIG_NET_IF_MAX_IPV4_COUNT=2 ../build/echo-server/zephyr/zephyr.exe -attach_uart This will create and run :zephyr:code-sample:`sockets-echo-server` with bridging enabled but not yet configured. To configure the bridging, you either need to use the bridge shell or call the bridging API directly from the application. We setup the bridging using the bridge shell like this: .. code-block:: console net bridge addif 1 3 2 net iface up 1 In the above example, the bridge interface index is 1, and interfaces 2 and 3 are Ethernet interfaces which are linked to interfaces ``zeth0`` and ``zeth1`` in the host side. The network interfaces look like this in Zephyr's side: .. code-block:: console net iface Hostname: zephyr Interface bridge0 (0x8090ebc) (Virtual) [1] ================================== Virtual name : No attached network interface. Link addr : 3B:DB:31:0F:CC:B6 MTU : 1500 Flags : NO_AUTO_START Device : BRIDGE_0 (0x8088354) Promiscuous mode : disabled IPv6 not enabled for this interface. IPv4 not enabled for this interface. Interface eth0 (0x8090fcc) (Ethernet) [2] =================================== Link addr : 02:00:5E:00:53:D2 MTU : 1500 Flags : AUTO_START,IPv4,IPv6 Device : zeth0 (0x808837c) Promiscuous mode : disabled Ethernet capabilities supported: TXTIME Promiscuous mode Ethernet PHY device: (0) IPv6 unicast addresses (max 3): fe80::5eff:fe00:53d2 autoconf preferred infinite 2001:db8::1 manual preferred infinite IPv6 multicast addresses (max 4): ff02::1 ff02::1:ff00:53d2 ff02::1:ff00:1 IPv6 prefixes (max 2): IPv6 hop limit : 64 IPv6 base reachable time : 30000 IPv6 reachable time : 18476 IPv6 retransmit timer : 0 IPv4 unicast addresses (max 1): 192.0.2.1/255.255.255.0 manual preferred infinite IPv4 multicast addresses (max 2): 224.0.0.1 IPv4 gateway : 0.0.0.0 Interface eth1 (0x80910dc) (Ethernet) [3] =================================== Link addr : 02:00:5E:00:53:87 MTU : 1500 Flags : AUTO_START,IPv4,IPv6 Device : zeth1 (0x8088368) Promiscuous mode : disabled Ethernet capabilities supported: TXTIME Promiscuous mode Ethernet PHY device: (0) IPv6 unicast addresses (max 3): fe80::5eff:fe00:5387 autoconf preferred infinite IPv6 multicast addresses (max 4): ff02::1 ff02::1:ff00:5387 IPv6 prefixes (max 2): IPv6 hop limit : 64 IPv6 base reachable time : 30000 IPv6 reachable time : 25158 IPv6 retransmit timer : 0 IPv4 unicast addresses (max 1): IPv4 multicast addresses (max 2): 224.0.0.1 IPv4 gateway : 0.0.0.0 The ``net bridge`` command will show the current status of the bridging: .. code-block:: console net bridge Bridge Status Config Interfaces 1 up ok 2 3 The ``addif`` command adds Ethernet interfaces 2 and 3 to the bridge interface 1. After the ``addif`` command, the bridging is still disabled because the bridge interface is not up by default. The ``net iface up`` command will turn on bridging. If you have wireshark running in host side and monitoring ``zeth0`` and ``zeth1``, you should see the same network traffic in both host interfaces. Note that interface index numbers are not fixed, the bridge and Ethernet interface index values might be different in your setup. The bridging can be disabled by taking the bridge interface down, and the Ethernet interfaces can be removed from the bridge using ``delif`` command. .. code-block:: console net iface down 1 net bridge delif 1 2 3