[lwip-users] igmp_set_timer() fix

[Marko Kiiskila]

Hi,

I encountered this issue few months back, and thought I'd share
the observation. igmp_set_timer() can still set it's timer value to 0,
which is not good. At least for me. My random number generator can
return 0.

address@hidden:~/src2/module/ext/LwIP/src/core/ipv4]$ diff -C 3
~/lwip/src/core/ipv4/igmp.c igmp.c
*** /Users/marko/lwip/src/core/ipv4/igmp.c      2014-03-13 16:47:44.000000000 
-0700
--- igmp.c      2014-03-14 11:59:05.000000000 -0700
***************
*** 699,709 ****
  {
    /* ensure the input value is > 0 */
  #ifdef LWIP_RAND
!   if (max_time == 0) {
!     max_time = 1;
!   }
    /* ensure the random value is > 0 */
!   group->timer = (LWIP_RAND() % max_time);
  #else /* LWIP_RAND */
    /* ATTENTION: use this only if absolutely necessary! */
    group->timer = max_time / 2;
--- 699,710 ----
  {
    /* ensure the input value is > 0 */
  #ifdef LWIP_RAND
!   if (max_time <= 1) {
!     group->timer = 1;
!   } else {
    /* ensure the random value is > 0 */
!     group->timer = (LWIP_RAND() % (max_time - 1)) + 1;
!   }
  #else /* LWIP_RAND */
    /* ATTENTION: use this only if absolutely necessary! */
    group->timer = max_time / 2;