Connecting from a Linux host

SSH (with shared internet)

Note

This guide only goes over Linux systems using NetworkManager or systemd-networkd

  1. Connect the OreSat Linux card to the host machine using a USB cable.

  2. In a terminal, run the following command and wait for an interface starting with enp or enx to appear.

The number following the enx or enp is the MAC address of the target’s interface. Note that it can change if the target is rebooted.

$ watch -n1 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
  ...
2: wlo1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
  ...
3: enp0s20f0u3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000
    link/ether 60:64:05:f9:0d:06 brd ff:ff:ff:ff:ff:ff
4: enp0s20f0u3i2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 60:64:05:f9:0d:08 brd ff:ff:ff:ff:ff:ff

If there are multiple interfaces whose name start with enp the target is usually connected to the enp*i2 interface (as shown above). If the interface name starts with enx interface, the target is usually connected to the interface with a higher number following the enx.

Only if the Linux host uses NetworkManager

  1. Install dnsmasq on your system.

  2. In another terminal, setup a DHCP server. Replace enp0s20f0u3i2 in the following command with the name found in previous step on your host.

Note

This guide use the nmcli command as the NetworkManager GUI is limited.

nmcli connection add type ethernet ifname enp0s20f0u3i2 ipv4.method shared con-name oresat-card

Note

This interface name can change if the target reboots. To change the intrerface name use the following.

nmcli connection modify oresat-card connection.interface_name [interface name]

You can rely on tab completion to discover the interface name.

Only if the Linux host uses systemd-networkd

  1. Setup the DHCP server, with your favorite IDE or text editor create a file with the name 20-oresat-card.network in the /etc/systemd/network directory. Add the following text to the file. Replace enp*i2 as needed.

  1. Restart systemd-networkd

sudo systemctl restart systemd-networkd

SSH using an IP address

  1. Go back to the terminal with watch ip a command running at wait for the address to be set. Make a note of the address and IPv4 address space; it should be something like 10.42.1.1/24.

$ watch -n1 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
  ...
2: wlo1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
  ...
3: enp0s20f0u3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000
  link/ether 60:64:05:f9:0d:06 brd ff:ff:ff:ff:ff:ff
4: enp0s20f0u3i2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
  link/ether 60:64:05:f9:0d:08 brd ff:ff:ff:ff:ff:ff
  inet 10.42.1.1/24 scope host lo
    valid_lft forever preferred_lft forever
  net6 fe80::cbcb:674d:2adf/64 scope link noprefixroute
    valid_lft forever preferred_lft forever

  1. Install ``nmap``_ on the Linux host.

  2. Run nmap to discover the card’s IP address. Replace 10.42.1.1/24 in the following command with the IPv4 address space found in the previous step. Alternatively, [linux_host_hostname].local/24 (e.g. thnkpd.local/24) will work as well on most distros.

$ nmap -sn 10.42.1.1/24
Starting Nmap 7.92 ( https://nmap.org ) at 2022-04-13 22:07 UTC
Nmap scan report for 10.42.1.1
Host is up (0.00079s latency).
Nmap scan report for 10.42.1.120
Host is up (0.0035s latency).
Nmap done: 256 IP addresses (2 hosts up) scanned in 2.63 seconds

That should print out two IP addresses (one is the Linux host and one is the OreSat card)

The terminal with watch ip a running is no longer needed.

  1. SSH onto the card. Password is temppwd. Replace 10.42.1.120 in the following command with other address that nmap found

ssh debian@10.42.1.120

SSH using multicast DNS (mDNS) domain

Note

mDNS is not configured by default on the target. To configure it add MulticastDNS=yes to \etc\systemd\network\10-usb0.network and restart systemd-networkd.

  1. SSH onto the card. Password is temppwd. Replace oresat-dev in the following command with other hostname

ssh debian@oresat-dev.local

For convenience, we can add oresat-dev.local to $HOME/.ssh/config.

Host oresat-dev.local
  HostName oresat-dev.local
  User debian

This gives the slight benefit of using tab completion when using ssh.

Mounting a remote directory with SSHFS

Mounting the target to the host filesystem makes it easy to transfer files, search the target’s file tree (try fzf, ripgrep, and zoxide), and remotely develop and deploy code to the target. To mount the target’s filesystem first install `sshfs`_ to your Linux host machine, then run the following command.

Verify the target has an internet connection

$ ping www.google.com
PING www.google.com (172.217.14.228) 56(84) bytes of data.
64 bytes from sea30s02-in-f4.1e100.net (172.217.14.228): icmp_seq=1 ttl=117 time=41.6 ms
64 bytes from sea30s02-in-f4.1e100.net (172.217.14.228): icmp_seq=2 ttl=117 time=29.1 ms

Serial

  1. Install picocom to the Linux host.

  2. Connect a USB to FTDI chip on the card debug board and to you system

picocom -b 115200 /dev/serial/by-id/usb-BeagleBoard*

Note

To exit picocom enter control-A-X