netdev - Re: ARP table question

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <49221929.7060504@candelatech.com>
Date:	Mon, 17 Nov 2008 17:23:53 -0800
From:	Ben Greear <greearb@...delatech.com>
To:	Rick Jones <rick.jones2@...com>
CC:	netdev@...r.kernel.org, Patrick McHardy <kaber@...sh.net>
Subject: Re: ARP table question

Rick Jones wrote:

>> +static unsigned long neigh_rand_retry(struct neighbour* neigh) {
>> +    if (neigh->parms->retrans_rand_backoff) {
>> +        return net_random() % neigh->parms->retrans_rand_backoff;
>> +    }
>> +    return 0;
>> +}
>> +
>>  /* Called when a timer expires for a neighbour entry. */
> 
> I thought that mod was something we tried to avoid?  Could you instead 
> use something that isn't random but perhaps varies among all the 
> requests?  Say some of the low-order bits of the IP being resolved?

This is only called when we are going to retransmit an ARP, which shouldn't
be in any sort of hot path, so I figured MOD was fine.

The net_random is a very cheap method (last I checked), as well.

So, I think that part is OK as it is, but I'm open to
persuasion :)

Thanks,
Ben

-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html