Sticky connections for multi wan

@hendrik

[root@nethserver ~]# ip ru
0:      from all lookup local
999:    from all lookup main
10000:  from all fwmark 0x10000/0xf0000 lookup IC2
10001:  from all fwmark 0x20000/0xf0000 lookup ITC1
20000:  from 91.209.1.56 lookup IC2
20000:  from 91.209.1.54 lookup ITC1
32765:  from all lookup balance
32767:  from all lookup default

So we markup all incoming traffic, thus no problem with misrouted traffic is observed.