[RTEMS Project] #2877: DHCP client fails on complex networks

[RTEMS trac]

#2877: DHCP client fails on complex networks
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 Reporter:  stavros.passas  |      Owner:
     Type:  defect          |     Status:  new
 Priority:  normal          |  Milestone:  4.12
Component:  General         |    Version:  4.12
 Severity:  normal          |   Keywords:  dhcp
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 What happens is that on networks with more than one DHCP servers, or on
 networks that use multiple vlans it can happen that After a DHCP discover
 our client broadcasts, it receives multiple offers, which is perfectly
 fine based on the DHCP RFC.

 However our implementation of a DHCP client, expects a linear execution
 flow:
 1. Broadcast a DHCP discover;
 2. Wait for a DHCP offer;
 3. Transmit a DHCP request;
 4. Wait for a DHCP ack;

 However the network stack is not cleaned between the reception of a DHCP
 offer and a DHCP ack, so if multiple offers are received, just the first
 one will be processed during the "Receive DHCP offer" phase, and the next
 one will be received when we expect a "DHCP ack", which makes our
 implementation assume the DHCP handshake is invalid and fail. Thus we
 restart the network and retry the whole process from the beginning which
 will cause the same issue again.

 This issue that is present from when I remember in RTEMS, definitely from
 4.10 up to now.

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Ticket URL: <http://devel.rtems.org/ticket/2877>
RTEMS Project <http://www.rtems.org/>
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