fix erroneous infos about DR in show neighbors/interfaces

[stormshield-rlibaert]

Description of problem

Pimctl can show wrong information about the DR identity for a given subnet. (in both sh neighbors and sh interfaces). If it is not itself, Pimd does not care about who is the DR but yet the information can be misleading. So even though the patch is mostly in pimd, it really just fixes info displayed by pimctl.

Solution

Fixing algorithm for electing the DR. Fixing display bug in the neihgbor table.

Tests

Mounted a multicast network with 3 routers in parallel, with especially:	Router	IP	Prio
1	192.168.20.171	5030
2	192.168.20.177	5020
3	192.168.20.181	5010

Before :
_______________________________________________________________________________
PIM Interface Table
===============================================================================
Interface         State     Address          Nbr  Hello  Prio  DR Address 
===============================================================================
vtnet1            Up        192.168.20.171     2      5  5030  192.168.20.171 
vtnet2            Up        192.168.21.182     2      5     1  192.168.21.186

===============================================================================
vtnet1            Up        192.168.20.177     2      5  5010  192.168.20.181 
vtnet2            Up        192.168.21.186     2      5     1  192.168.21.186

===============================================================================
vtnet1            Up        192.168.20.181     2      5  5020  192.168.20.177 
vtnet2            Up        192.168.21.140     2      5     1  192.168.21.186

After:
_______________________________________________________________________________
PIM Interface Table
===============================================================================
Interface         State     Address          Nbr  Hello  Prio  DR Address 
===============================================================================
vtnet1            Up        192.168.20.171     2      5  5030  192.168.20.171 
vtnet2            Up        192.168.21.182     2      5     1  192.168.21.186

===============================================================================
vtnet1            Up        192.168.20.177     2      5  5030  192.168.20.171 
vtnet2            Up        192.168.21.186     2      5     1  192.168.21.186

===============================================================================
vtnet1            Up        192.168.20.181     2      5  5030  192.168.20.171 
vtnet2            Up        192.168.21.140     2      5     1  192.168.21.186

• Fixing output of pimctl sh neighbors :

  Before:
  _______________________________________________________________________________
  PIM Neighbor Table
  ===============================================================================
  Interface         Address          Prio  Mode  Uptime/Expires               
  ===============================================================================
  vtnet1            192.168.20.181   5010  0h1m7s  0h1m7s/0h0m12s              
  vtnet1            192.168.20.177   5020  0h1m7s  0h1m7s/0h0m17s              
  vtnet2            192.168.21.186      1  DR    0h1m7s/0h0m17s              
  vtnet2            192.168.21.140      1  0h1m7s  0h1m7s/0h0m17s

  After:
  _______________________________________________________________________________
  PIM Neighbor Table
  ===============================================================================
  Interface         Address          Prio  Mode  Uptime/Expires               
  ===============================================================================
  vtnet1            192.168.20.181   5010        0h0m1s/0h0m17s              
  vtnet1            192.168.20.177   5020        0h0m1s/0h0m17s              
  vtnet2            192.168.21.186      1  DR    0h0m1s/0h0m17s              
  vtnet2            192.168.21.140      1        0h0m1s/0h0m17s

[troglobit]

Wow, awesome work on this! :100::+1:

There are only some minor whitespace/coding style issues, but I'll fix them up myself when I merge this later tonight.