steffenschumacher / massdhclient Goto Github PK

Is your feature request related to a problem? Please describe.
When roc-compliant clients fail to obtain addresses, they implement a backoff algorithm to ensure they do not DoS the DHCP server in cases where it is experiencing a high load. Without this, our client would do the same.

Describe the solution you'd like
Each failed attempt by a DHCP client to either request or renew a lease, must increment a counter, which can be used to derive a backoff delay, until next attempt is done. Furthermore, the time of the last failed attempt must also be stored, so that the precise time of the next attempt can be calculated. The formula must be 0.5+log(failed_attempts)*20 to find how many seconds to wait until the next attempt.

Describe alternatives you've considered
Static and random algorithms produce undesired side effects

Additional context
N/A

Is your feature request related to a problem? Please describe.
If the offered address is being used by some host which can/will not respond to an ICMP probe from the DHCP server the client will currently use the offered address unaware of the potential issue

Describe the solution you'd like
On receiving a DHCP offer, the client must perform an arp get for the offered IP address and wait ~100 ms for a reply, before requesting the address from the DHCP server. If a response is unexpectedly seen, the client must issue a DHCPDECLINE to the DHCP server.

Describe alternatives you've considered
Using both ICMP from the server would work in cases where the holder of the IP has a route to the DHCP server, and is configured to respond to ICMP, however neither will always be the case.

Additional context
This is required to be rfc compliant..