Advice required for sending STP BPDU traffic between tap interfaces connected by common bridge

Need advice for the bridge tap interface to run stp traffic.

  1. created the tap interface and bridge  
  2. Have come across stp BPDU is consumed by bridge.
  3. i’m running the scapy on the host, however i’m not seeing the stp BPDU on the bridge nor on the tapB interface when i run the tcppdump, please advise4.
  4. My intent is to send/inject stp BPDU via  tapA and should receive on tapB or any tap interfaces on that bridge.
  5. I see packets with tcpdump on tapA, but they do not pass to bridge nor tapB interface.

scapy

Sent 1 packets.

send(Ether(dst=”01:80:c2:00:00:00″)/LLC()/STP(), iface=”tapA”)
WARNING: Mac address to reach destination not found. Using broadcast


sendp(Dot3(dst=”01:80:c2:00:00:00″,src=”08:17:35:51:29:2e”)/LLC(dsap=0xaa, ssap=0xaa)/SNAP(OUI=0x0c, code=0x010b)/STP(), iface=”tapA1″, count=1)

Sent 1 packets.

I’m running the tap listener where i open the scokets and recv/read the data on the tap interfaces for tapA and tapB

configuration:

root@santosh-virtualbox:/home/santosh#sudo brctl addbr testbridge
root@santosh-virtualbox:/home/santosh#sudo ip tuntap add mode tap tapA
oot@santosh-virtualbox:/home/santosh#sudo ip tuntap add mode tap tapB 
root@santosh-virtualbox:/home/santosh#sudo brctl addif testbridge  tapA
root@santosh-virtualbox:/home/santosh#sudo brctl addif testbridge  tapB
root@santosh-virtualbox:/home/santosh#sudo brctl show 
bridge name     bridge id        STP enabled     interfaces
testbridge    8000.8207f065cdfb       no          tapA
                                                  tapB 

root@santosh-virtualbox:/home/santosh#sudo ip addr add 192.168.67.1/24 dev tapA
root@santosh-virtualbox:/home/santosh#sudo ip addr add 192.168.67.2/24 dev tapB
ip link set dev tapA up 
ip link set dev tapB up
ip link set dev testbridge up

ifconfig Output.

santosh@santosh-virtualbox:~/linux_source$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:26:cd:de brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global dynamic noprefixroute enp0s3
       valid_lft 85637sec preferred_lft 85637sec
    inet6 fe80::f7db:f963:8e15:157e/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
3: enp0s8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:60:7a:a6 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.6/24 brd 192.168.1.255 scope global dynamic noprefixroute enp0s8
       valid_lft 234879sec preferred_lft 234879sec
    inet6 2401:4900:1f26:12bd:ba44:a1f5:3a20:8b18/64 scope global dynamic noprefixroute
       valid_lft 86317sec preferred_lft 86317sec
    inet6 fe80::1475:613b:ad77:89ee/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
4: testbridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether c2:26:1a:8b:d9:d0 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::c026:1aff:fe8b:d9d0/64 scope link
       valid_lft forever preferred_lft forever
5: tapA: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master testaux state UP group default qlen 1000
    link/ether 72:1c:e2:96:9d:d4 brd ff:ff:ff:ff:ff:ff
    inet 192.168.67.1/24 scope global tapA
       valid_lft forever preferred_lft forever
    inet6 fe80::701c:e2ff:fe96:9dd4/64 scope link
       valid_lft forever preferred_lft forever
6: tapB: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master testaux state UP group default qlen 1000
    link/ether ca:07:2e:eb:c5:12 brd ff:ff:ff:ff:ff:ff
    inet 192.168.67.2/24 scope global tapB
       valid_lft forever preferred_lft forever
    inet6 fe80::c807:2eff:feeb:c512/64 scope link
       valid_lft forever preferred_lft forever

 Regards,Santosh

Answer

Attribution
Source : Link , Question Author : Santosh Kumar , Answer Author : Community

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