Updates #3053. Squashed commit of the following: commit eb68a21436536d67b6d23873e6b6f291912bf3a1 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Fri May 14 18:58:15 2021 +0300 dhcpd: do not panic commit 423678934e736e842fc90042ee0037d1efa912ee Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Fri May 14 18:18:49 2021 +0300 dhcpd: support decline and release msgs