Skip to content

Freertr - Unleashed

Freertr - Unleashed

References

[1] http://docs.freertr.org/guides/getting-started/003-unleash/

[2] https://unix.stackexchange.com/questions/152331/how-can-i-create-a-virtual-ethernet-interface-on-a-machine-without-a-physical-ad

[3] https://askubuntu.com/questions/1004388/sysctl-permission-denied

Tutorial

2 Installation

2.1 Pre-requisites

In order to illustrate this binding operation, I've added one new interfaces to my VirtualBox Debian guest OS.

sudo lsmod | grep dummy
sudo modprobe dummy
sudo lsmod | grep dummy
dummy                  16384  0
sudo ip link add enp0s9 type dummy

run ip a

ip a
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether fa:16:3e:24:34:d8 brd ff:ff:ff:ff:ff:ff
    altname enp0s3
    inet 10.55.2.161/24 metric 100 brd 10.55.2.255 scope global dynamic ens3
       valid_lft 85276sec preferred_lft 85276sec
    inet6 fe80::f816:3eff:fe24:34d8/64 scope link 
       valid_lft forever preferred_lft forever

As this interface is totally controlled by freeRtr we need to reset it:

ip addr flush dev enp0s9

In order to avoid future problem (disable TCP-offload)

cat <<EOF | sudo tee /root/tcp-offload-off.sh

#! /bin/bash

/sbin/ethtool -K \$1 rx off
/sbin/ethtool -K \$1 tx off
/sbin/ethtool -K \$1 sg off
/sbin/ethtool -K \$1 tso off
/sbin/ethtool -K \$1 ufo off
/sbin/ethtool -K \$1 gso off
/sbin/ethtool -K \$1 gro off
/sbin/ethtool -K \$1 lro off
/sbin/ethtool -K \$1 rxvlan off
/sbin/ethtool -K \$1 txvlan off
/sbin/ethtool -K \$1 ntuple off
/sbin/ethtool -K \$1 rxhash off

EOF

sudo chmod u+x /root/tcp-offload-off.sh

sudo /root/tcp-offload-off.sh enp0s9

Result

sudo /root/tcp-offload-off.sh enp0s9
Actual changes:
tx-checksum-ip-generic: off
tx-tcp-segmentation: off [not requested]
tx-tcp-ecn-segmentation: off [not requested]
tx-tcp-mangleid-segmentation: off [not requested]
tx-tcp6-segmentation: off [not requested]
Actual changes:
tx-scatter-gather: off
tx-scatter-gather-fraglist: off
tx-generic-segmentation: off [not requested]
Could not change any device features

Enable promiscuous mode and set MTU to 8192 as freeRtr is able to handle jumbo frames

sudo ip link set enp0s9 up promisc on mtu 8192

Enable enp0s9

sudo ip link set enp0s9 up

IPv6 will be handled by freeRtr, therefore we disable IPv6 from Linux perspective

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
sudo sysctl -w net.ipv6.route.flush=1

FreeRouter S/w

Let's add an additional interface definition eth3

  • eth3, A-end:127.0.0.1 1003 ---- B-end:127.0.0.1 5003

In this example B-end will be stitched to an existing Linux interface. r1@eth3 which has socket 127.0.0.1 1003 will be bind to enp0s9 Linux interface. In order to accomplish this, we will use a simple tool called pcapInt part of freeRtr bundles

Let's first install freeRtr addtional tools bundle.

sudo mkdir /rtr
cd /rtr
wget http://www.freertr.net/rtr.jar

install Dependencies

sudo apt-get install --no-install-recommends --no-install-suggests --yes default-jre-headless

These tools are basically tools used to ensure freeRtr packet forwarding in different context and dataplane.

~/rtr$ ls -ltrh *.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 vlan.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 ttyLin.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 tapInt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 stdLin.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 sender.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 rawInt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 ptyRun.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 pcapInt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 pcap2pcap.bin
-rwxr-xr-x 1 dcollin5 dcollin5  27K Dec 31  2009 p4xdp_user.bin
-rw-r--r-- 1 dcollin5 dcollin5 1.3K Dec 31  2009 p4xdp_pass.bin
-rw-r--r-- 1 dcollin5 dcollin5 101K Dec 31  2009 p4xdp_kern.bin
-rw-r--r-- 1 dcollin5 dcollin5 1.3K Dec 31  2009 p4xdp_drop.bin
-rwxr-xr-x 1 dcollin5 dcollin5 135K Dec 31  2009 p4udp.bin
-rwxr-xr-x 1 dcollin5 dcollin5  23K Dec 31  2009 p4pkt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  23K Dec 31  2009 p4mnl_user.bin
-rw-r--r-- 1 dcollin5 dcollin5 4.3K Dec 31  2009 p4mnl_kern.bin
-rwxr-xr-x 1 dcollin5 dcollin5 136K Dec 31  2009 p4emu.bin
-rwxr-xr-x 1 dcollin5 dcollin5  39K Dec 31  2009 p4dpdkPkt.bin
-rwxr-xr-x 1 dcollin5 dcollin5 156K Dec 31  2009 p4dpdkDbg.bin
-rwxr-xr-x 1 dcollin5 dcollin5 152K Dec 31  2009 p4dpdk.bin
-rwxr-xr-x 1 dcollin5 dcollin5 140K Dec 31  2009 p4dbg.bin
-rwxr-xr-x 1 dcollin5 dcollin5 135K Dec 31  2009 p4bench.bin
-rwxr-xr-x 1 dcollin5 dcollin5  19K Dec 31  2009 modem.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 mapInt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  19K Dec 31  2009 hdlcInt.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 dummyCon.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 daemonRun.bin
-rwxr-xr-x 1 dcollin5 dcollin5  15K Dec 31  2009 bundle.bin