4 Feb
2006
4 Feb
'06
12:01 p.m.
Hi Greg,
at the moment there is no retry support for neither NAPTR nor SRV. The
resolver loops through all NAPTR/SRV records and looks for the first
NAPTR|SRV|A pair of records that can be successfully resolved to IP address.
The biggest problem with having retry support for the resolve is the
combination between parallel and serial forking. Lets supposed the
following scenario:
uriA parallel forks to uriX and uriY
both uriX and uriY leads to distinctive sets of NAPTR/SRV records.
in such a case, even if it's a single transaction, you have to keep the
state of the resolver for each branch to be able to do serial forking
independently on each of them.
Another problem is detecting the failures. According to "4.3 Details of
RFC 2782 Process" specifies usage on ICMP for UDP failures...and ICMP
support is not reliable (depends on OS) and tricky to implement.
Do not get me wrong, I am not saying it's impossible, but it will take
some time to get to it... :)
regards,
Bogdan
Greg Fausak wrote:
Bogdan,
This is great news! Thank you! I've got
a questions about retries.
I'm curious if retries are built in, or do I employ t_on_failure?
What I mean is...
How do I get the t_relay() to try subsequent naptrs and/or srvs in the
event the current one fails? Is all of that automatic, or do I need
a t_on_failure?
I think I understand that you skip ones that don't resolve, but, what if
they resolve but the transaction times out either on the naptr or on the srv?
Best,
-g
--
Greg Fausak
greg(a)thursday.com