* [9fans] bug in network stack regarding Ipht
@ 2015-06-08 22:35 yoann padioleau
2015-06-09 8:07 ` cinap_lenrek
0 siblings, 1 reply; 2+ messages in thread
From: yoann padioleau @ 2015-06-08 22:35 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
Hi,
I think I’ve found a bug in the network stack.
in 9/ip/ip.h there is
struct Ipht
{
Lock;
Iphash *tab[Nipht];
};
where Night is 521,
but then in 9/ip/ipaux.c there is
ulong
iphash(uchar *sa, ushort sp, uchar *da, ushort dp)
{
return ((sa[IPaddrlen-1]<<24) ^ (sp << 16) ^ (da[IPaddrlen-1]<<8) ^ dp ) % Nhash;
}
where Nhash is just 64,
so lots of entries in Ipht.tab will never be used. This slows down every ip+port lookups in the UDP and TCP code.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [9fans] bug in network stack regarding Ipht
2015-06-08 22:35 [9fans] bug in network stack regarding Ipht yoann padioleau
@ 2015-06-09 8:07 ` cinap_lenrek
0 siblings, 0 replies; 2+ messages in thread
From: cinap_lenrek @ 2015-06-09 8:07 UTC (permalink / raw)
To: 9fans
good catch!
--
cinap
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-06-09 8:07 ` cinap_lenrek
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