This directory contains patch files for LwIP that enable required or desired functionality in Matter. Patches that are not yet integrated into mainline LwIP are provided as a patch file. This file also contains a list of helpful patches that may not be present in vendor forks of the LwIP codebase
Required for wifi devices to support communication with a thread device behind an open thread border router.
Troubleshooting: The patch uses the ip6_addr_net_eq function, which is a recent API change on upstream LwIP. The previous version of this function is ip6_addr_netcmp, so this function call may need to be replaced on older forks.
In earlier version of lwIP, there is a bug where the RA processing fails if the RA includes an LLADDR option with a hw address that is not the max length. This happens for thread devices. Relevant patches from lwIP main that should be applied back to any Matter device using an older version of lwIP:
https://git.savannah.nongnu.org/cgit/lwip.git/commit/?id=7807f706f357d2eea85d9927d970991dc4b1ef90 https://git.savannah.nongnu.org/cgit/lwip.git/commit/?id=6f700a157d1049a06ab9c467057d71e98e7798de
There was a bug in the DHCPv6 code where if the router sent a DNS using DHCPv6 stateless, it would set the DNS server as an ipv4 address, which ended up being garbage. This would invalidate the whole DNS table, and lwip does not have a default backup.