On Mon, Apr 16, 2012 at 03:05:54PM +0100, Ed W wrote: > Hi, I'm suffering extreme performance problems with getaddrinfo > being used by ipset to do conversions from IP textual strings to > number. Although the IP address is textual there is a reverse DNS > lookup performed and in the event that my resolver is slow, this is > sometimes taking 60seconds or so to return
I have not looked at the source, but I suspect this is a uClibc bug based on a misreading of the standard. Many incorrect historical getaddrinfo implementations performed unnecessary reverse dns lookups to fill in the ai_canonname field of the addrinfo structure. POSIX is very clear that this is wrong: A numeric host address string is not a ``name'', and thus does not have a ``canonical name'' form; no address to host name translation is performed. See below for handling of the case where a canonical name cannot be obtained. Source: http://pubs.opengroup.org/onlinepubs/9699919799/functions/getaddrinfo.html Rich _______________________________________________ uClibc mailing list [email protected] http://lists.busybox.net/mailman/listinfo/uclibc
