Subject: Re: [net-next-2.6 PATCH v7 3/7 RFC] TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS

From: William Allen Simpson <[email-masked]>
Date: Sat, 21 Nov 2009 11:51:13 -0500

David Miller wrote:
> From: William Allen Simpson <[email-masked]>
> Date: Fri, 20 Nov 2009 09:33:51 -0500
> 
>> @@ -59,6 +59,14 @@ int sysctl_tcp_base_mss __read_mostly = 512;
>>  /* By default, RFC2861 behavior.  */
>>  int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
>>  
>> +#ifdef CONFIG_SYSCTL
>> +/* By default, let the user enable it. */
>> +int sysctl_tcp_cookie_size __read_mostly = 0;
>> +#else
>> +int sysctl_tcp_cookie_size __read_mostly = TCP_COOKIE_MAX;
>> +#endif
>> +
> 
> I would prefer if the default did not depend upon whether
> SYSCTL is enabled or not.  That's extremely non-intuitive.
> 
> 
This code was based on net/ipv4/tcp_minisocks.c for syncookies.
Apparently, default for syncookies has been controversial.

Would you accept always default to TCP_COOKIE_MAX?

The code already automatically reduces the size of the cookie to
match available space in the TCP options (part 1f).