Bug 1811119

Note to QE: this bug should probably be verified in coordination with the original bug reported against OSP: https://bugzilla.redhat.com/show_bug.cgi?id=1801006 (the original bug is TestOnly).

I can reproduce this bug on version:
# rpm -qa|grep ovn
ovn2.11-central-2.11.1-33.el8fdp.x86_64
ovn2.11-2.11.1-33.el8fdp.x86_64
ovn2.11-host-2.11.1-33.el8fdp.x86_64

and verified on version
ovn2.11-central-2.11.1-37.el8fdp.x86_64
ovn2.11-2.11.1-37.el8fdp.x86_64
ovn2.11-host-2.11.1-37.el8fdp.x86_64

server:
local dhcp_102=$(ovn-nbctl create DHCP_Options cidr=42.42.42.0/24 \
                        options="\"server_id\"=\"42.42.42.254\" \"server_mac\"=\"00:de:ad:ff:01:02\" \
                        \"lease_time\"=\"3600\" \"router\"=\"42.42.42.254\"")
                echo $dhcp_102

                ovn-nbctl ls-add ls
                ovn-nbctl lsp-add ls vm1
                ovn-nbctl lsp-set-addresses vm1 "00:00:00:00:00:01 42.42.42.2"
                rlRun "ovn-nbctl lsp-set-dhcpv4-options vm1 $dhcp_102"
                rlRun "ovn-nbctl lsp-get-dhcpv4-options vm1"
                ovn-nbctl lsp-add ls vm2
                ovn-nbctl lsp-set-addresses vm2 "00:00:00:00:00:02 42.42.42.3"
                rlRun "ovn-nbctl lsp-set-dhcpv4-options vm2 $dhcp_102"
                rlRun "ovn-nbctl lsp-get-dhcpv4-options vm2"

                ip netns add vm1
                ovs-vsctl add-port br-int vm1 -- set interface vm1 type=internal
                ip link set vm1 netns vm1
                ip netns exec vm1 ip link set vm1 address 00:00:00:00:00:01
                ip netns exec vm1 ip link set vm1 up
                ip netns exec vm1 ip link set lo up
                ovs-vsctl set Interface vm1 external_ids:iface-id=vm1

client:
ip netns add vm2
                ovs-vsctl add-port br-int vm2 -- set interface vm2 type=internal
                ip link set vm2 netns vm2
                ip netns exec vm2 ip link set vm2 address 00:00:00:00:00:02
                ip netns exec vm2 ip link set vm2 up
                ip netns exec vm2 ip link set lo up
                ovs-vsctl set Interface vm2 external_ids:iface-id=vm2


                rlRun "ip netns exec vm2 tcpdump -U -i vm2 -w a.pacp&"
                sleep 5
then send packet asbelow:
conf.checkIPaddr = False
    fam,hw =get_if_raw_hwaddr(conf.iface)
    sendp(Ether(src="00:00:00:00:00:02", dst="ff:ff:ff:ff:ff:ff")/IP(src="0.0.0.0", dst="255.255.255.255")/UDP(sport=68,dport=67)/BOOTP(flags=32768,chaddr=hw)/DHCP(options=[("message-type","discover"),"end"]),iface="vm2")


pkill -9 tcpdump
tcpdump -r a.pacp -nn -v |grep 42.42.42.254.67.*255.255.255.255.*BOOTP/DHCP.*Reply'
reading from file a.pacp, link-type EN10MB (Ethernet)
    42.42.42.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 276, Flags [Broadcast]


on the old version, the reply packet is a unicast packet.
# tcpdump -r b.pacp -nn -v
reading from file b.pacp, link-type EN10MB (Ethernet)
04:34:56.679758 IP (tos 0x0, ttl 64, id 1, offset 0, flags [none], proto UDP (17), length 272)
    0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:00:00:00:00:02, length 244, Flags [Broadcast]
	  Client-Ethernet-Address 00:00:00:00:00:02
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Discover
04:34:56.681402 IP (tos 0x0, ttl 64, id 1, offset 0, flags [none], proto UDP (17), length 304)
    42.42.42.254.67 > 42.42.42.3.68: BOOTP/DHCP, Reply, length 276, Flags [Broadcast]
	  Your-IP 42.42.42.3
	  Client-Ethernet-Address 00:00:00:00:00:02
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Offer
	    Lease-Time Option 51, length 4: 3600
	    Subnet-Mask Option 1, length 4: 255.255.255.0
	    Default-Gateway Option 3, length 4: 42.42.42.254
	    Server-ID Option 54, length 4: 42.42.42.254

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:1458