Bug#438179: getaddrinfo() sorts results.
Kurt Roeckx a écrit :
> reopen 438179
> On Thu, Aug 16, 2007 at 08:24:51PM +0200, Aurelien Jarno wrote:
>> This is a feature, not a bug. getaddrinfo() sorts results according to
>> RFC3484. You can configure the way they are sorted using /etc/gai.conf.
> None of the rules in rfc3484 say anything about this. In fact, the last
> rule says:
> Rule 10: Otherwise, leave the order unchanged.
> If DA preceded DB in the original list, prefer DA. Otherwise prefer
Rule 9 comes before:
Rule 9: Use longest matching prefix.
When DA and DB belong to the same address family (both are IPv6 or
both are IPv4): If CommonPrefixLen(DA, Source(DA)) >
CommonPrefixLen(DB, Source(DB)), then prefer DA. Similarly, if
CommonPrefixLen(DA, Source(DA)) < CommonPrefixLen(DB, Source(DB)),
then prefer DB.
That's why you see small variation among the returned address.
> Also, I don't see an option to prevent it from sorting the list.
Because this thing is not configurable. This is not required by the RFC
and this is a bad idea as you start using IPv6.
>> If you don't want results to be sorted, don't use getaddrinfo().
> Do you have a suggestion for an other interface that works with
> different address types other than getipnodebyname()?
No I don't. Anyway if you don't want to sort to the returned addresses,
you only want to do that for IPv4, and thus need two different interfaces.
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
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