The guest network stack might DHCPREQUEST an address that the slirp built
in dhcp server can't let it have - for example if the guest has an old
leases file from another network configuration. In this case the dhcp
server should and does reject the request and prepares to send a DHCPNAK
to the client.
However, in this case the daddr variable in bootp_reply() is set to
0.0.0.0. Shortly afterwards, it unconditionally attempts to pre-insert the
new client address into the ARP table. This causes an assertion failure in
arp_address_add() because of the 0.0.0.0 address.
According to RFC2131, DHCPNAK messages for clients on the same subnet
must be sent to the broadcast address (S3.2, subpoint 2).
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
90d7416ab1