How to bond network interfaces?

orion777 · Posted: Wed Jan 03, 2018 8:45 pm Post subject: How to bond network interfaces?

I'm newbee, sorry about that. I'm very interested in two interfaces bonding. The primary consideration to increase availability of the connection, however, I would like to try network balancing to.
The key problem, that I'm found a couple of how-to use ifenslave, but most of them are 10 years old and reports DIFFERENT configuration! Some of them require fully manual config of the network (what, seems, is ignored in my system), other require kernel config; miimon and bonding type specification is aso different..

https://syzygytech.com/?p=106

https://forums.gentoo.org/viewtopic-t-198607-start-0.html

https://habrahabr.ru/post/58218/

https://wiki.archlinux.org/index.php/Netctl_

That why I'm asking about bond config here; to make it clear and to exclude possibility to make my device unbootable (raspberry pi3b)

What I have:
- rpi-4.10 kernel
- running dhcpcd
- (optionally NetworkManager and/or dhclient CAN be runned, but these are not in autostart for now)
- ls /sys/class/net reports my interfaces correctly; also ifconfig reports all my network interfaces
- config in /etc/conf.d/net is ignored (at least I was trying to specify static IP configuration for the eth1, but eth1 still gets its ip by means of dhcpcd)

khayyam

orion777

khayyam

orion777 · Posted: Fri Jan 05, 2018 5:16 pm Post subject:

I have no running NetworkManager, only dhcpcd is in autostart. eth1 is attached via usb.
Here it is:

khayyam · Posted: Fri Jan 05, 2018 7:30 pm Post subject:

orion777 ...

that all seems consistent to me (if a little difficult to figure out what you're doing). If you want dhcpcd to ignore the interface then add '--denyinterfaces <pattern>' as a parameter, or config, for dhcpcd, eg:

orion777 · Posted: Sat Jan 06, 2018 8:22 am Post subject:

I have to use two usb cellular 3G/4G dongles huawei 3372h simultaneously. The problem is that all 3372h have same mac-address and these cannot be changed (this problem is well known and was discussed in cellular modem forum), also you can take a look at udevadm when both dongles are attached, here in post #3 https://forums.gentoo.org/viewtopic-t-1072550.html
By default, NetworkManager starts dhclient for the first inserted dongle, while second inserted was ignored and ip was not assigned by dhclient (probably due of similar mac-addresses). Than I was disabling NetworkManager (hence there are also no child process dhclient), than dhcpcd was added into autorun and now both dongles gets their ip by means of dhcpcd (by the cost that DNS server is not working and all requests should be done thru ip, hence emerge,etc cant recognize servers and are not working).

WHAT I WANT:
I want to connect two 3G/4G dongles and mate them together to get reliable solution (by means of parallel redundant network) for moving equipment (remotely controlled car-robot with camera, that why I'm using raspberry pi 3b with sakakis' rpi64 image https://github.com/sakaki-/gentoo-on-rpi3-64bit ). Dongles have different ip and gateway addresses, probably these can be configured manually to exclude dhcp problem, but these MUST be assigned based on eth number, NOT mac-address (as ethers are same). Dongles eth numbers are assigned by USB port number, hence are same all the time

szatox · Advocate Joined: 27 Aug 2013 Posts: 3603

orion777 · Posted: Sun Jan 07, 2018 8:08 am Post subject:

szatox · Advocate Joined: 27 Aug 2013 Posts: 3603

Alright.... Well, I have bad feelings about this setup, but you could try to circumvent some limitations of public networks by means of an overlay network.
Say, you could try setting up 2 VPN connections (one over each GSM link) to a single server. and then connect tap devices with a bridge or a bond.
There was even a kernel driver for fault tolerant networks that would broadcast your packet via all interfaces and only pick the first copy on the receiving end, dropping the rest, so changing paths does not add any latency at all. Sorry, can't recall its name right now.

Using those 2 VPNs or tunnels or whatever separates your transport layer from your public IP and lets you create a single IP space spanning both those links. Since your connection (source IP, source port, destination IP, destination port and sequence number) are not affected by the underlying GSM connection anymore, so you can unplug GSM without immediately breaking your connection in the overlay, so you can either re-establish that tunnel or switch to the other tunnel with exactly the same set of IPs at its ends.

I've never tried this myself, but you can try e.g. GRE tunnels or openvpn in bridged mode.
Also, you will need some tricks to do the routing properly. You will probably connect from your vehicle to a single remote IP. It calls for source-based routing (can be done with multiple routing tables, linux kernel supports this). And then you have to open each connection from a manually selected local IP rather than using the default.

I still I don't really like your idea, there are a lot of things than can go wrong, but you may research the above approach if you feel adventurous.

orion777 · Posted: Sun Jan 07, 2018 8:08 pm Post subject:

Thanks for the idea.

But I'm still is confusing: Who is responsible to read /etc/conf.d/net ?? As specified here https://wiki.gentoo.org/wiki/Handbook:Parts/Networking/Modular/en#Interface_handlers preliminary network configuration is done there, but if /etc/conf.d/net is empty, than it will use dhcp by default.

My /etc/conf.d/net was created manually, because by default net was not exist in my gentoo. Maybe here I was wrong?
Because static IP config is ignored for build-in ethernet card to (now NetworkManager is running)!

szatox · Advocate Joined: 27 Aug 2013 Posts: 3603

/etc/conf.d/net is read by netifrc.
You can invoke it by linking /etc/init.d/net.<your interface name> to /etc/init.d/net.lo and then calling the service by newly created name.
So, if your interface is called eth0, you do cd /etc/init.d; ln -s net.lo net.eth0; ./net.eth0 start
and then it will load variables defined in /etc/conf.d/net and apply those related to eth0.

As I think of it now, you may have to define dependencies by yourself, to ensure openrc starts network interfaces in the correct order.
Also, setups with redundant connections are prone to loops. If you find out your network misbehaves, remove one link and see if it gets better.

orion777 · Posted: Mon Jan 08, 2018 7:06 pm Post subject:

szatox · Advocate Joined: 27 Aug 2013 Posts: 3603

orion777 · Posted: Tue Jan 09, 2018 6:43 pm Post subject:

Yep, seems that You are right..
I was trying to set the following configuration

eth3 -> 192.168.8.* - NAT (gateway 192.168.8.1) -> external ip
----------------------------------------------------------------------------------------> cellular provider server 1020.237.42 -> ... wan ...
eth4 -> 192.168.8.* - NAT (gateway 192.168.8.1) -> external ip

eth3 and eth4 was bonded with ip 192.168.8.100 default gateway 192.168.8.1, however /etc/init.d/net.bond8 start returns error on line 170, write error for both eth3 and eth4.

orion777 · Posted: Tue Jan 09, 2018 6:48 pm Post subject:

So, what next?
1) is it hand to setup two vpn from cmd (without x-servers) ?
2) maybe I have to try http://multipath-tcp.org/ ?
I'm noob in linux, unfortunately :roll:

szatox · Advocate Joined: 27 Aug 2013 Posts: 3603

That multipath tcp looks interesting, I think I've seen something like that running on an enterprizy server, though it was called by different name. Unfortunately I do not know nearly enough details to estimate its usefulness for your case. I've seen it running within a local network.
Anyway, in linux everything can be done from command line without Xserver.
You're trying to do something quite tricky there, so whichever option you chose, you will have to do your own research on this topic. It's certainly going to be a funny little project, but you can't really skip the research part. Good news is, it's gonna make you less noob :lol:

For GRE this one looks promissing
http://lartc.org/howto/lartc.tunnel.gre.html
In case of openvpn you'd have to write your own config file. It's not the most basic setup though, so my guess is gre would be easier.