cxcast is a userland application to encapsulte BUM packets in specified VXLAN. It helps VXLAN devices that do not have Multicast based MAC/VTEP learning.
How to use: git clone https://github.com/upa/cxcast, cd cxcast and make.
cxcast creates a tap interface, and encapsulates BUM packets transmitted to the tap interface in specified VXLAN, UDP and IP headers.
./cxcast: invalid option -- 'h'
usage of cxcast
-t [IFNAME] : tap interface name
-v [VNI] : VNI for tap interface
-i [IFNAME] : underlay interface name (optional)
-m MACADDR_MCASTADDR_SRCADDR : mac/mcast/source mapping
One tap interface is one VNI. Source and Destination UDP port numbers are 4789. UDP checksum is 0. MACADDR of -m option means source MAC address of BUM packets. ff:ff:ff:ff:ff:ff matches all source MAC addresses (defualt entry). Multiple -m options are permitted. To encapsulate BUM packets of multiple segments, run multiple cxcast processes with different tap interface names at the same time.
% sudo ./cxcast -t vxlan10 -v 10 -m ff:ff:ff:ff:ff:ff_239.0.0.1_172.16.10.11 &
main [414] install MAC_MCAST_SRC entry ff:ff:ff:ff:ff:ff_239.0.0.1_172.16.10.11
mac_list_add [111] install defualt MAC entry, MCAST=239.0.0.1 SRC=172.16.10.11
main [455] tap_fd:3, raw_fd:4
% ifconfig vxlan10
vxlan10 Link encap:Ethernet HWaddr a2:98:d6:d9:f2:8a
inet6 addr: fe80::a098:d6ff:fed9:f28a/64 Scope:Link
UP BROADCAST RUNNING MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:0 (0.0 B) TX bytes:508 (508.0 B)
%
Then, create br interface, bridge the segument that you want to encap BUM packets and the tap interface.
% sudo brctl addbr br0
% sudo ip link set dev br0 up
% sudo brctl addif br0 eth2
% sudo brctl addif br0 vxlan10
% brctl show
bridge name bridge id STP enabled interfaces
br0 8000.a298d6d9f28a no eth2
vxlan10
%
All BUM packets from eth2 are encapsulated in VXLAN header, UDP header and IP header with source 172.16.10.11 destination 239.0.0.1.
To join multicast address group (send IGMP report for snooping), use socat.
apt-get install socatsocat STDIO UDP4-RECV:1234,ip-add-membership=239.0.0.1:eth0