[PATCH 1/7] Babel: Make sure intervals don't overflow.

[Toke Høiland-Jørgensen]

Ondrej Zajicek <santiago at crfreenet.org> writes:

> On Mon, May 02, 2016 at 07:07:49PM +0200, Toke Høiland-Jørgensen wrote:
>> Intervals are carried as 16-bit centisecond values, but kept internally
>> in 16-bit second values, which causes a potential for overflow. This
>> adds some checks to make sure this doesn't happen.
>> 
>> +  /* make sure we don't overflow the 16-bit centisec fields */
>>    if (!BABEL_IFACE->update_interval)
>> -    BABEL_IFACE->update_interval = BABEL_IFACE->hello_interval*BABEL_UPDATE_INTERVAL_FACTOR;
>> -  BABEL_IFACE->ihu_interval = BABEL_IFACE->hello_interval*BABEL_IHU_INTERVAL_FACTOR;
>> +    BABEL_IFACE->update_interval = MIN_(BABEL_IFACE->hello_interval*BABEL_UPDATE_INTERVAL_FACTOR, BABEL_MAX_INTERVAL);
>> +  BABEL_IFACE->ihu_interval = MIN_(BABEL_IFACE->hello_interval*BABEL_IHU_INTERVAL_FACTOR, BABEL_MAX_INTERVAL);
>
> This is not completely correct, because IHU interval is not independent
> of hello_interval in this implementation - IHUs are sent for each
> BABEL_IHU_INTERVAL_FACTOR hellos even if ihu_interval is limited by this.

Yeah, you're right. Hmm, guess it doesn't really make sense to have the
IHU interval configurable by itself, then?

-Toke