[Dnsmasq-discuss] timing of dhcp-script for tftp downloads

Simon Kelley simon at thekelleys.org.uk
Sat Nov 16 15:01:15 GMT 2013

On 16/11/13 14:21, Maule Mark wrote:
> When is dhcp-script called after doing a tftp download?  Is that script
> invoked immediately, or is it queued operation that has an indeterminate
> delay between tftp completion and script start?

It's queued at transfer completion. There are at least two sources of delay.

1) Only one instance of the script is running at any time, so a TFTP 
completion event can be queued indefinitely waiting for a previous 
invocation of the script to exit.

2) "transfer completion" is defined as receipt of the ACK for the last 
block, but some clients never send this: as soon as they have all the 
blocks they return, and never send the last ACK; also the last ACK may 
be lost. In this case, the transfer complete at the server occurs after 
multiple timeouts and retransmissions, at the point at which a failed 
transfer would otherwise be signalled.

> Also, is there any way to know when a tftp download starts vs.ends?

No, I don't think so.



> thanks
> Mark
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