[Olsr-dev] BUGs found in MPR selection algorithm and Default message Forwarding Algorithm

[Andres Medina]

This mail is to report 2 bugs we found it the code of olsrd. As we don't 
use the source control utilities that you have and we are not involved 
in the development of the code, I'm going to do my best to describe the 
two bugs here:

Bug #1:
Navigate to line 175 of mpr.c of the olsrd-0.5.6-r3 code or look for the 
following piece of code in your current source:
--
    if (second_hop_entries->neighbor_2->mpr_covered_count >= 
olsr_cnf->mpr_coverage)
      count++;
--

The count variable holds the number of nodes that are reached by the 
current MPR set. The variable mpr_coverage is set to 1 and never 
changes. The condition of the "if" is satisfied every time the node is 
reached by an MPR. Thus, when a node is reached by two MPRs, then this 
count is incremented by two, which should not be the case. The solution 
is very simple: the condition should be changed to == insted of >=.

Bug #2:
Navigate to line 319 of olsr.c of the olsrd-0.5.6-r3 code or look for 
the following piece of code in your current source:
--
  /* Check MPR */
  if (olsr_lookup_mprs_set(src) == NULL) {
#ifdef DEBUG
    struct ipaddr_str buf;
    OLSR_PRINTF(5, "Forward - sender %s not MPR selector\n", 
olsr_ip_to_string(&buf, src));
#endif
    return 0;
  }

  if (olsr_message_is_duplicate(m)) {
    return 0;
  }

--

The code olsr_message_is_duplicate(m), should be executed even if the 
node processing the packets is not an MPR of the src node. This is also 
very easy to correct.

-- 
Andres Medina
Department of Electrical and Computer Engineering
University Of Delaware
(spam-protected)