garogers01/switchlink

Netlink listener library

Switchlink

The switchlink library provides a Netlink listener that listens to kernel notifications for network events (link, address, neighbor, route, etc.) and uses the switchsai library to program the data plane described in the switch.p4 program in the p4factory repository.

+---------------------------------------------------+
|                    Switchlink                     |
|                                                   |
+-----------------------+---------------------------+
|          SAI          |                   ^
|                       |                   |
+-----------------------+                   |
|      Switch API       |                   |
|                       |                   |
+-----------------------+---------+         |
|      Resource Mgmt. API         |         |
| (auto-gen. from switch.p4)      |         | Netlink events
+---------------------------------+         |
|        Soft Switch              |         |
|  (compiled from switch.p4)      |         |
+---------------------------------+         |
                                            |
                                            |
+----------------------------------------------------------------+
|                             Kernel                             |
|                                                                |
+----------------------------------------------------------------+

The switchlink library listens to NETLINK messages only on 'swp' interfaces. The 'swp' interfaces are TUNTAP interfaces that represent the softswitch's physical ports. Each 'swp' interface is mapped to a physical port (see src/switchlink_db.c). Applications (bridge-utils, mstpd, iputils, Quagga, etc.) interact with the softswitch via the 'swp' interfaces. Users can use native Linux tools to configure the 'swp' interfaces.

The 'swp' interfaces are created as shown below:

ip tuntap add dev swp1 mode tap
ip tuntap add dev swp2 mode tap
ip tuntap add dev swp3 mode tap
ip tuntap add dev swp4 mode tap
ip link set swp1 up
ip link set swp2 up
ip link set swp3 up
ip link set swp4 up

Sample L2 configuration:

# Create a bridge and add two interfaces

brctl addbr v100
brctl addif v100 swp1
brctl addif v100 swp2
ip link set v100 up

# Add few static MAC addresses

bridge fdb add  00:00:00:00:11:02 dev swp1 master temp
bridge fdb add  00:00:00:00:22:02 dev swp2 master temp

Sample L3 configuration:

# Add interface IP addresses

ip address add 172.16.30.1/24 broadcast + dev swp3
ip address add 172.16.40.1/24 broadcast + dev swp4

ip address add 2ffe:3::1/70 dev swp3
ip address add 2ffe:4::1/48 dev swp4

# Add neighbors

ip neigh add 172.16.30.2 lladdr 00:00:00:00:33:02 dev swp3
ip neigh add 172.16.40.2 lladdr 00:00:00:00:44:02 dev swp4
ip neigh add 172.16.40.3 lladdr 00:00:00:00:44:03 dev swp4

ip neigh add 2ffe:3::2 lladdr 00:00:00:00:33:02 dev swp3
ip neigh add 2ffe:4::2 lladdr 00:00:00:00:44:02 dev swp4
ip neigh add 2ffe:4::3 lladdr 00:00:00:00:44:03 dev swp4

# Add routes

ip route add 172.16.101.0/24 nexthop via 172.16.40.2
ip route add 172.16.102.0/24 nexthop via 172.16.40.2 nexthop via 172.16.40.3

ip route add 3ffe:2::/64 nexthop via 2ffe:4::2
ip route add 3ffe:3::/64 nexthop via 2ffe:4::2 nexthop via 2ffe:4::3

Supported Features

1. Basic L2 switching
2. Basic L3 Routing: IPv4
3. L2 protocol integration (mstpd)
4. L3 protocol integration (Quagga)
5. ECMP

Upcoming Features

1. L2: Learning and aging
2. IPv6
3. LAG