Difference between revisions of "Openwrt"
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https://github.com/sirMackk/py3tftp | https://github.com/sirMackk/py3tftp | ||
The only downside is the need for pip. | The only downside is the need for pip. | ||
| + | |||
| + | ===Always test with RAM only images=== | ||
| + | Test firmware images without writing them to flash by using ramdisk | ||
| + | images. | ||
| + | |||
| + | In make menuconfig select Target Images and then you can select the | ||
| + | ramdisk option. | ||
| + | |||
| + | This will create an image with kernel + initramfs, that will have | ||
| + | initramfs in the name. The resulting image can be loaded in the device | ||
| + | through the bootloader's tftp function and should boot to a prompt | ||
| + | without relying on flash/filesystem support. | ||
===various links i found interesting=== | ===various links i found interesting=== | ||
Revision as of 05:01, 5 November 2022
Recommended Router
Current:
high traffic: x86 PC
low traffic: ARM / MIPS with the following:
* uboot bootloader * doesn't require multiple hoops to install (i.e. no 'two different' serial speeds on the same UART. moron ubiquiti...) * promotes FOSS and is ok with LEDE/openwrt
Still evaluating them, but it looks like gl.inet is the way to go.
OLD:
I used to use these as they are rack mount, but the bootloader is proprietary and i had two of them brick themselves for no reason during the 2nd sysupgrade. Proprietary software. Not Even Once.
High-end companies can look at https://www.opencompute.org/products
Recommended wireless AP
Open mesh in Oregon was good. But they were bought out. They are now doomed. China has gl.inet which is basically the same as open mesh, although they specialize in small travel routers. Only buy wifi APs that support openwrt.
Tips
port forwarding
Port forwarding is two steps:
- redirect port from outside to internal (NAT)
- allow access from outside to inside via this port (firewall)
Contents of /etc/config/firewall
Note: Proto can be 'tcp' OR 'tcpudp' OR 'udp'
reserved ip / static lease
Contents of /etc/config/dhcp
ref: https://openwrt.org/docs/guide-user/base-system/dhcp_configuration#static_leases
I tried to add this to the wiki, but someone (https://openwrt.org/docs/guide-user/base-system/dhcp_configuration?rev=1596434574) decided to replace my simple solution with an obfuscated one that requires uci commands. So instead, it will remain here. EDIT: I added it back. See how long that lasts...
openvpn
opkg install openvpn-openssl
Contents of /etc/config/openvpn
And your .ovpn in /etc/openvpn/.
aliases
Put in /etc/profile. e.g.
export TERM=xterm alias vpnme= 'openvpn --config /etc/openvpn/myconfigfile.ovpn & ./script.sh &'
mwan3
Mwan3 can be tricky. The wiki lacks a quick start*. The following files get edited:
/etc/config/network /etc/config/mwan3 /etc/config/firewall
Tips Page: Mwan3_On_Openwrt
If you add a new WAN interface, (e.g. wanb or wan2) you must add wanb to the existing wan firewall zone for outgoing comms. How this is handled differs from 17 to 19.*2
Balanced policies can have issues with connections jumping from one wan to another.
* the current mwan3 page is a lengthy multi-page behemoth (which has grown over time) that expects no less of you than to understand all functional and architectural details of how the failover works. It's a lot for someone that just wants to setup backup internet. But mwan3 can and does work.
- 2 ctrl-f for firewall comes up with half a dozen mentions of firewall masking (something done automatically) and one easily missable note, for GUI setup only, about adding the new wan2 to the firewall zone. An absolutely required step.
iptables vs fw3
In the firewall:
iptables -L
will list current rules, but the iptables rule generator is fw3.
fw3 print
Will display iptables commands that make up the firewall. fw3 script is described in firewall pages on official wiki. Please review that. 22 now uses nft.
nft list tables
less with / search
The stock 'less' command does not include '/' search.
opkg install less
To get forward slash search https://dev.archive.openwrt.org/ticket/7132
remove poweroff command
cd /sbin/ rm ./poweroff
Now to power off, you must type
busybox poweroff
This will keep you from accidentally shutting down a router.
misc
start wifi
wifi up wifi status
transfer files using nc / scp on lean embedded devices
Logging
display (RAM based) logs (note that this is not in /var/log/messages...)
logread
https://openwrt.org/docs/guide-user/perf_and_log/start e.g. https://openwrt.org/docs/guide-user/perf_and_log/statistic.custom and https://openwrt.org/docs/guide-user/perf_and_log/log.messages
Blink LEDs
If you poke around the Linux Kernel you will come across core Netfilter configuration. It's not in an obvious place, but in 5.4 here:
Location: │ │ -> Networking support (NET [=y]) │ │ -> Networking options │ │ -> Network packet filtering framework (Netfilter) (NETFILTER [=y]) │ │ -> Core Netfilter Configuration │ │ -> Netfilter Xtables support (required for ip_tables) (NETFILTER_XTABLES [=y])
Why am I poking around xtables support? Wireguard needs it for <5.6. But, in this page, you will find some familiar sights: REDIRECT,MASQUERADE,DROP,LOG, etc... All parameters for iptables. Here you will learn what the difference between REDIRECT and MASQUERADE is (one is input, one is output)(which is interesting, because it might be a thing people commonly get wrong, on online tips for using iptables, or if you don't know which does what, you won't know what to look for). Forget about that, there's one named LED. Hey that sounds interesting. That means I can control a LED from the firewall?
Does this work with Openwrt? No idea, but from here I went to the official owrt docs
https://openwrt.org/docs/guide-user/base-system/led_configuration
And you may already know the leds are there, but here's how to configure them. Some of them require modules. e.g.
The LED flashes with link status and/or send and receive activity on the configured interface. If not installed already, install it with: opkg install kmod-ledtrig-netdev
will enable netdev, which will enable led activity on any NIC. so it requires that module and some configuration... e.g.
#:/sys/devices/platform/leds/leds/:green:wan# ls brightness device_name link rx trigger uevent device interval max_brightness subsystem tx #:/sys/devices/platform/leds/leds/:green:wan# cat * 0 cat: read error: Is a directory eth0.2 50 0 255 1 cat: read error: Is a directory none switch0 timer default-on [netdev] phy0rx phy0tx phy0assoc phy0radio phy0tpt 0 OF_NAME=wan OF_FULLNAME=/leds/wan OF_COMPATIBLE_N=0
I had to set rx or tx to 1 (only 1 of them). and also needed to set device_name (not device like docs say) to eth0.2
Just set a ping, then tweak the knobs; should start blinking.
"But what if I want to blink more LEDs from userspace?" See Arduino for ulisp.
Quick TFTP
This is purported to work easy. From: http://web.archive.org/web/20211017192705/https://sagacioussuricata.com/posts/meraki-mr33/
On Windows, there is the excellent tftpd64 project, but unfortunately there doesn’t seem to be anything similar to it on Linux. The solution that finally worked for me was py3tftp, as I was able to put up a functional TFTP server serving the current working directory by simply running sudo py3tftp -v -p 69.
https://github.com/sirMackk/py3tftp The only downside is the need for pip.
Always test with RAM only images
Test firmware images without writing them to flash by using ramdisk images.
In make menuconfig select Target Images and then you can select the ramdisk option.
This will create an image with kernel + initramfs, that will have initramfs in the name. The resulting image can be loaded in the device through the bootloader's tftp function and should boot to a prompt without relying on flash/filesystem support.
various links i found interesting
- https://openwrt.org/docs/guide-user/network/traffic-shaping/sqm - speed test, and traffic shaping to speed up a 'slow' network. protip: use x86 instead of arm if openwrt is slow.
- https://openwrt.org/docs/guide-user/services/nas/netatalk_configuration - apple time machine backup server
- https://openwrt.org/docs/guide-user/network/wan/multiwan/mwan3 - failover for wan. i have used this before, and it worked well.
- https://openwrt.org/tag/faq - FAQs
- https://openwrt.org/docs/techref/flash.layout - Partitions on
HDDflash. And overlay fs.
- https://openwrt.org/docs/techref/start - Technical Reference. Has some informative dives into various aspects of low power routers. As an example see this link on flash: https://openwrt.org/docs/techref/flash IME, flash is built in obsolescence. usb drives, sd cards, and onboard flash tend to last much less than advertised. not recommended. SD and SSDs are a trap. from this: even 'reading' flash can cause bad blocks. that's right, even reading. therefore flash is guaranteed to fail. tech companies love it.
- https://forum.openwrt.org/t/favor-to-do-custom-build-for-anyone-w-dev-toolchain/138275 Appears to be a basic device add to the owrt tree, copying existing code.
- http://web.archive.org/web/20211017192705/https://sagacioussuricata.com/posts/meraki-mr33/ Showing how to flash to nand from owrt running in ram, i think.
- web.archive.org/web/https://cybergibbons.com/hardware-hacking/recovering-firmware-through-u-boot/
- https://forum.openwrt.org/t/x86-booting-two-instances-of-openwrt/106282 have a backup owrt partition on x86 (possibly useful for upgrades)
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