Download Firmware OpenWrt 21.02

Version 21.02 of OpenWrt has been released. OpenWrt is an alternative open source firmware for a large number various routers and embedded devices. By means of the opkg package management system there is the possibility to determine for yourself what the router can and cannot do. Also on GoT there are several people actively working on it, see this topic. You can simply update the version with sysupgrade from the web interface. The main improvements made in this release are listed below.

WPA3 support included by default

WPA3 was already supported in 19.07 but it was not provided by the default set of packages in OpenWrt images. With 21.02, all packages necessary to provide WPA3 are installed by default in OpenWrt images. WPA3 is supported by most Wi-Fi drivers in OpenWrt.

TLS and HTTPS support included by default

TLS support is now provided by default in OpenWrt images including the trusted CA certificates from Mozilla. It means that wget and opkg now support fetching resources over HTTPS out-of-the-box. The opkg download server is accessed through HTTPS by default. OpenWrt switched from mbedTLS to wolfSSL as the default SSL library. mbedTLS and OpenSSL are still available and can be installed manually.

In addition, LuCI is now available over HTTPS in addition to HTTP. There is no automatic redirection to HTTPS on a fresh OpenWrt 21.02 installation; however, redirection will be enabled after upgrading from OpenWrt 19.07 to OpenWrt 21.02. It is always possible to activate or deactivate the redirection to HTTPS.

Initial DSA support

DSA stands for Distributed Switch Architecture and is the Linux standard to deal with configurable Ethernet switches. OpenWrt 21.02 comes with initial support for DSA, which replaces the swconfig system that OpenWrt was using up until now. Not all targets have been ported: some devices still use swconfig while some devices already switched to DSA.

This is a significant change to how switch ports and VLANs are managed. As such, sysupgrade will not be able to convert existing swconfig configuration to DSA configuration (see “Upgrading” below). See the OpenWrt DSA Networking documentation for details. The following targets are using a switch managed with DSA in OpenWrt 21.02:

• ath79 (TP-Link TL-WR941ND only)
• bcm4908
• gemini
• kirkwood
• mediatek (most boards)
• mvebu
• octeon
• ramips (mt7621 subtarget only)
• realtek

Increased minimum hardware requirements: 8 MB flash, 64 MB RAM

Due to new features being introduced and the general size increase of the Linux kernel, devices now need at least 8 MB of flash and 64 MB of RAM to run a default build of OpenWrt. More flash space is recommended for extensibility, see 8/64 warning

It is still possible to build custom OpenWrt images (eg using the ImageBuilder) that may fit devices with 4 MB of flash or 32 MB of RAM. However, the level of functionality will be reduced and there is no guarantee to stability. see OpenWrt on 4/32 devices for more details and guidance.

New network configuration syntax and board.json change

There have been several changes to the network configuration syntax in /etc/config/network:

• in config interface, option ifname has been renamed to device (since it refers to a device section)
• in config device of type bridge, ifname has been renamed to ports
• for new installs, the generated configuration now creates separate sections for layer 2 (config device) and layer 3 (config interface) configuration

The old syntax is still supported to facilitate transition, and there is no automated migration when upgrading.

However, the LuCI web interface detects old-style configuration and will propose to migrate it to the new syntax. This is necessary to be able to edit network configuration through LuCI.

New UCI syntax

The new configuration style looks like this:

config device option name ‘br-lan’ option type ‘bridge’ option macaddr ’00:01:02:XX:XX:XX’ list ports ‘lan1’ list ports ‘lan2’ list ports ‘lan3’ list ports ‘lan4’ 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 ‘eth1′ option macaddr ’00:01:02 :YY:YY:YY’ config interface ‘wan’ option device ‘eth1’ option proto ‘dhcp’ config interface ‘wan6’ option device ‘eth1’ option proto ‘dhcpv6’

This example uses DSA with lanX interface names. A non-DSA device would use more classical ethX interface names.

Changes to board.json

In addition, network fields in board.json have also been renamed from “ifname” to “device”. In addition, DSA bridges now expose their list of ports in a “ports” attribute. If you rely on board.json, this change is not backwards compatible.

Example for a DSA bridge:

“network”: { “lan”: { “ports”: [
“lan1”,
“lan2”,
“lan3”,
“lan4″
]”protocol”: “static” }, “wan”: { “device”: “wan”, “protocol”: “dhcp” } }

Example for a classical swconfig switch configuration:

“network”: { “lan”: { “device”: “eth0”, “protocol”: “static” }, “wan”: { “device”: “eth1”, “protocol”: “dhcp” } }
New hardware targets

A new realtek target has been added, which is often found in managed switches. As a result, it is now possible to run OpenWrt on devices with a significant number of Ethernet ports. See supported devices for realtek. In addition, new bmc4908 and rockchip targets have been added. Support for many new boards was added to the existing targets.

Dropped hardware targets

The ar71xx target was deprecated in OpenWrt 19.07 and has been gradually replaced by ath79, see ar71xx-ath79 migration. With OpenWrt 21.02, the ar71xx has now been removed and users must use ath79 instead. If you are still running with the ar71xx target, it is recommended to reinstall OpenWrt 21.02 from scratch. Users already on the ath79 target can use sysupgrade to upgrade to OpenWrt 21.02. Other targets were also removed: cns3xxx, rb532 and samsung.

ASLR activated

Network exposed user space applications are linked as position-independent executable (PIE) to allow full Address Space Layout Randomization (ASLR) support. This makes it harder for attackers to exploit OpenWrt. see Hardening build options for more details.

Kernel with container support

Multiple Linux kernel compile options, needed for Linux Containers (LXC) and procd-ujail are activated by default for most targets. This allows to use LXC and ujail with the normal release builds.

SELinux support

It is possible to compile OpenWrt with SELinux support. This is currently not activated by default.

Core components update

Core components have the following versions in 21.02.0:

• Updated tool chain:
  • musl libc 1.1.24
  • glibc 2.33
  • gcc 8.4.0
  • binutils 2.34
• Updated Linux kernel
  • 5.4.143 for all targets
• Network:
  • hostapd 2020-06-08, dnsmasq 2.85, dropbear 2020.81
  • cfg80211/mac80211 from kernel 5.10.42
  • wireguard backport from upstream Linux kernel
• System user country:
  • busy box 1.33.1

In addition to the listed applications, many others were also updated.

Upgrading to 21.02.0

Sysupgrade can be used to upgrade a device from 19.07 to 21.02, and configuration will be preserved in most cases.

• Sysupgrade from 18.06 to 21.02 is not supported.
• There is no migration path for targets that switched from swconfig to DSA. In that case, sysupgrade will refuse to proceed with an appropriate error message:
  Image version mismatch. image 1.1 device 1.0 Please wipe config during upgrade (force required) or reinstall. Config cannot be migrated from swconfig to DSA Image check failed
• The default root file system partition size changed for targets/devices relying on booting from mass storage (HDD, USB flash, SD card, etc.), so MBR will change and any additional partition will be deleted when sysupgrading.

Known issues

• Some IPv6 packets are dropped when software flow offloading is used: FS#3373
  As a workaround, do not activate software flow offloading, it is deactivate by default.