Hey, the following Setup i got. I installed openwrt on my Mikrotik. after that i installed openvswitch. Then i configurated a bridge. The Bridge looks like this
OFPT_FEATURES_REPLY (xid=0x2): dpid:000048a98aecb172
n_tables:254, n_buffers:0
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
2(br-lan.2): addr:48:a9:8a:ec:b1:72
config: 0
state: 0
current: 1GB-FD
speed: 1000 Mbps now, 0 Mbps max
3(br-lan.3): addr:48:a9:8a:ec:b1:72
config: 0
state: 0
current: 1GB-FD
speed: 1000 Mbps now, 0 Mbps max
4(br-lan.4): addr:48:a9:8a:ec:b1:72
config: 0
state: 0
current: 1GB-FD
speed: 1000 Mbps now, 0 Mbps max
5(br-lan.5): addr:48:a9:8a:ec:b1:72
config: 0
state: 0
current: 1GB-FD
speed: 1000 Mbps now, 0 Mbps max
LOCAL(ovs-br): addr:48:a9:8a:ec:b1:72
config: PORT_DOWN
state: LINK_DOWN
speed: 0 Mbps now, 0 Mbps max
OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0
Becuse i need some mac`s on the port i setted it via ovs-vsctl get Interface br-lan.3 mac="48:a9:8a:a9:32:33" for example for port 3
On port 2 i got a pc (Ip Addresse= 10.10.1.1, Default Gateway = 10.10.1.254) on Port 3 i got another pc (ip-address=10.10.123.1, Defaut-gateway=10.10.123.254). So now leats try to make an nat router. For this i create an arp reply out of the arp request the router get.
ovs-ofctl add-flow ovs-br "table=0,in_port=3,arp,arp_op=1,arp_tpa=10.10.123.254 actions=\
load:2->arp_op,\
move:arp_spa->arp_tpa,\
load:0x0a0a7bfe->arp_spa,\
move:arp_sha->arp_tha,\
load:0x48a98aa93233->arp_sha,in_port"
ovs-ofctl add-flow ovs-br "table=0,in_port=2,arp,arp_op=1,arp_tpa=10.10.1.254 actions=\
load:2->arp_op,\
move:arp_spa->arp_tpa,\
load:0x0a0a01fe->arp_spa,\
move:arp_sha->arp_tha,\
load:0x48a98aa93222->arp_sha,in_port"
ovs-ofctl add-flow ovs-br "table=0,in_port=2,ip,ip_dst=10.10.123.1 actions=\
dec_ttl,\
move:eth_dst->eth_src,\
load:mac of my pc on port 3->eth_dst,\
output:br-lan.3"
So on my pc on port 3 i think its working (with wireshark i can see that the reply says: 10.10.123.254 is at 48:a9:8a:a9:32:33.
With this configuration. The pc on port 2 doesnt build his arp tablle and the ping from port 2 to 3 doesnt work