All,
I have a milkV-duo (Pi Pico look-alike running Risc chip) that runs Linux
(busybox) and provides an RNDIS network interface to the host. For some reason
when I connect the device to Arch, it is properly identified and the network
device is created, but the interface is always brought up DOWN. Providing an
address with ip link (it runs on 192.168.42.1) seems to enable the interface,
but when you ssh to that IP it just logs into the Arch host instead of the
milkV-duo.
On connect the rndis host interface is created:
Jan 05 00:30:34 2pi kernel: usb 2-8: new high-speed USB device number 6
using ehci-pci
Jan 05 00:30:34 2pi kernel: usb 2-8: device descriptor read/64, error -71
Jan 05 00:30:34 2pi kernel: usb 2-8: New USB device found, idVendor=3346,
idProduct=1009, bcdDevice= 5.10
Jan 05 00:30:34 2pi kernel: usb 2-8: New USB device strings: Mfr=1, Product=2,
SerialNumber=3
Jan 05 00:30:34 2pi kernel: usb 2-8: Product: RNDIS
Jan 05 00:30:34 2pi kernel: usb 2-8: Manufacturer: Cvitek
Jan 05 00:30:34 2pi kernel: usb 2-8: SerialNumber: 0123456789
Jan 05 00:30:34 2pi kernel: rndis_host 2-8:1.0 usb0: register 'rndis_host' at
usb-0000:00:1d.7-8, RNDIS device, 22:39:53:06:09:42
Jan 05 00:30:34 2pi kernel: rndis_host 2-8:1.0 enp0s29f7u8: renamed from usb0
But then for some reason the dnsmasq-dhcpd running on the chip doesn't get
an address to automatically enable the interface. Checking Arch you have:
# ip addr
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 noprefixroute
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group
default qlen 1000
link/ether 00:23:ae:89:58:90 brd ff:ff:ff:ff:ff:ff
inet 192.168.6.111/24 brd 192.168.6.255 scope global dynamic
noprefixroute enp2s0
valid_lft 4986sec preferred_lft 4086sec
inet6 fe80::b133:3c77:ce09:5b19/64 scope link
valid_lft forever preferred_lft forever
5: enp0s29f7u8: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
link/ether 22:39:53:06:09:42 brd ff:ff:ff:ff:ff:ff
Simply assigning an IP allows you to ping it and get a ssh prompt:
# ip addr add 192.168.42.1 broadcast + dev enp0s29f7u8
# ping 192.168.42.1
PING 192.168.42.1 (192.168.42.1) 56(84) bytes of data.
64 bytes from 192.168.42.1: icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from 192.168.42.1: icmp_seq=2 ttl=64 time=0.018 ms
64 bytes from 192.168.42.1: icmp_seq=3 ttl=64 time=0.049 ms
^C
--- 192.168.42.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2015ms
# ssh david@192.168.42.1
david@192.168.42.1's password:
You have new mail.
Last login: Fri Jan 5 00:30:05 2024 from 192.168.6.114
00:33 2pi:~> l
total 920
drwx------ 41 david david 4096 Jan 5 00:30 .
drwxr-xr-x 12 root root 4096 Aug 30 23:11 ..
drwxr-xr-x 2 david david 4096 Jul 10 2022 .FreeCAD
<snip...>
However, that has just logged into the host and not the milkV-duo board. So
it almost looks like it is considering enp0s29f7u8 as alias for loopback. I
must be missing something easy and fundamental, but I can't figure out what.
Of course, plugging it into Win10 and using PuTTY, the address is already
there and ssh connects directly to the board and not the host. There is no
route added:
# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default _gateway 0.0.0.0 UG 1002 0 0 enp2s0
192.168.6.0 0.0.0.0 255.255.255.0 U 1002 0 0 enp2s0
Adding the address with ip link enables avahi-daemon for the interface and
mdns:
Jan 05 00:54:38 2pi avahi-daemon[328]: Joining mDNS multicast group on
interface enp0s29f7u8.IPv4 with address 192.168.42.1.
Jan 05 00:54:38 2pi avahi-daemon[328]: New relevant interface enp0s29f7u8.IPv4
for mDNS.
Jan 05 00:54:38 2pi avahi-daemon[328]: Registering new address record for
192.168.42.1 on enp0s29f7u8.IPv4.
Jan 05 00:54:39 2pi avahi-daemon[328]: Joining mDNS multicast group on
interface enp0s29f7u8.IPv6 with address fe80::2039:53ff:fe06:942.
Jan 05 00:54:39 2pi avahi-daemon[328]: New relevant interface enp0s29f7u8.IPv6
for mDNS.
Jan 05 00:54:39 2pi avahi-daemon[328]: Registering new address record for
fe80::2039:53ff:fe06:942 on enp0s29f7u8.*.
Anybody else mess with one of these boards or a similar RNDIS device and
know how to successfully bring the interface up so you can connect with the
milkV board and not the host?
--
David C. Rankin, J.D.,P.E.
