Re: dhcpd uses bad current time

[Gerhard Roth]

On Wed, 15 May 2013 10:15:54 +0200
Gerhard Roth <gr...@genua.de> wrote:

> In dhcpd, variable cur_time is set only once per dispatch loop.
> Unfortunately, this is done before the poll(2) call. Since poll(2)
> may sleep for an arbitrary amount of time, the value of cur_time
> might refer to some long ago point in time. When message dispatching
> is done, timeouts and lease ends are calculated based on this
> outdated cur_time value that was set before the call to poll(2).
> 
> It's fine to set cur_time only once per loop, but we should do it after
> the blocking poll(2) syscall so that its value is more accurate.
> 
> ok?
> 
> Gerhard
> 


Sorry, the previous version will break timeout handling when there
are no incoming packets. I notice the moment that I sent the mail.

So let's keep all the old code and just add another update of cur_time
after poll(2).

Gerhard


Index: usr.sbin/dhcpd/dispatch.c
===================================================================
RCS file: /cvs/src/usr.sbin/dhcpd/dispatch.c,v
retrieving revision 1.30
diff -u -p -r1.30 dispatch.c
--- usr.sbin/dhcpd/dispatch.c   19 Apr 2013 21:25:39 -0000      1.30
+++ usr.sbin/dhcpd/dispatch.c   15 May 2013 08:26:49 -0000
@@ -360,6 +360,7 @@ another:
                case 0:
                        continue;       /* no packets */
                }
+               time(&cur_time);
 
                for (i = 0, l = protocols; l; l = l->next) {
                        struct interface_info *ip = l->local;