[PATCH] Be more permissive on NAKs

Cherry-picked from
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/
master/net-misc/dhcpcd/files/patches/dhcpcd-6.8.2-Be-more-permissive-on-
NAKs.patch.

Previously, we'd reject NAKs that did not include a server ID.
Since we'd only check that a server ID was present, but did not
validate it against any stored state, the test is merely pedantic.
Moreover, some DHCP servers (e.g. OpenBSD 4.6) send NAK messages
without a server ID. [1]

To improve compatibility with real-world DHCP servers, drop the
check for the presence of a server ID.

BUG: 22956197
Change-Id: I11515205b89affde5bc61eb95e6615db450d6176

Reviewed-on: https://chromium-review.googlesource.com/194972
1 file changed