Networking

Sep

2023

Where to find cheap RJ45 connectors

Generally, I always recommend going with metal-shielded RJ45 ports since those tend not to break as often.

If you want to buy more than, say, 10pcs, you can check out LCSC’s Ethernet Connectors / Modular Connectors lineup. The very good prices compensate for the shipping fee even when buying only medium quantities.

Note that it’s easy to mix up models with and without magnetics at the moment as there is no suitable filter. It’s easiest to just look at the length of the connector – RJ45 connectors without magnetics are almost cubic in size (i.e. length in the direction where you insert the connector is equal to the width) whereas connectors with magnetics are much longer. Nevertheless, always check the datasheet.

Some examples:

With magnetics:

HanRun HR913124A, Two LEDs, includes magnetics, right angle, EMI shielding tabs, THT, 0,89€/pc @ 100pcs
HanRun HR913129C, Two LEDs, includes magnetics, right angle, EMI shielding tabs, THT, 0,69€/pc @ 100pcs
HanRun HR911105A, Two LEDs, includes magnetics, right angle, No EMI shielding tabs, THT, 0.80€/pc @ 100pcs
- Much cheaper on AliExpress, 100pcs @ 0,65€, single piece @0,38€ plus shipping, 50pcs @0,6318€/pc

No magnetics:

RCH RC01133, No LEDs, no magnetics, right angle, THT, 0.11€/pc @100pcs
HC-WK88-H16-DB, Two LEDs, no magnetics, right angle, THT, 0.14€/pc @ 100pcs
RJ45-B-1*1, Two LEDs, no magnetics, shield with case contacts, 0.22€/pc @ 100pcs

Sep

2023

How to access RouterOS API in Python using the ‘routeros’ library (minimal example)

This example uses the routeros library from PyPI (GitHub) to access the MikroTik API and extract the system identity.

#!/usr/bin/env python3
from routeros import login

routeros = login('admin', 'abc123abc', '192.168.88.1')

output = routeros('/system/identity/print')
# Extract the one identity string from the list of dictionaries
print(output[0]['name'])

Sep

2023

Netmiko MikroTik RouterOS SSH key login example

In our previous example Netmiko MikroTik RouterOS minimal example we showed how to login to a RouterOS device using netmikoand password-based login.

#!/usr/bin/env python3  
from netmiko import ConnectHandler
import os.path
mikrotik = {
    'device_type': 'mikrotik_routeros',
    'host':   '192.168.88.1',
    'username': 'admin',
    'key_file': os.path.expanduser("~/.ssh/id_mikrotik"),
}
with ConnectHandler(**mikrotik) as mikrotik_connection:
    print(mikrotik_connection.send_command(f'/system/identity/print', cmd_verify=False))

Example output:

name: MySwitch01

Sep

2023

How to parse Ethernet packet header (src & dst MAC addresses) using lwIP

You can use this code, for example, in a custom packet handler function.

#include <lwip/prot/ethernet.h>

eth_hdr* hdr = reinterpret_cast<eth_hdr*>(buffer);
auto srcMAC = hdr->src.addr;
auto dstMAC = hdr->dest.addr;

Serial.printf("Received packet: Packet of length %d\n", len);
Serial.printf("    Src MAC: %02X:%02X:%02X:%02X:%02X:%02X\n", srcMAC[0], srcMAC[1], srcMAC[2], srcMAC[3], srcMAC[4], srcMAC[5]);
Serial.printf("    Dst MAC: %02X:%02X:%02X:%02X:%02X:%02X\n", dstMAC[0], dstMAC[1], dstMAC[2], dstMAC[3], dstMAC[4], dstMAC[5]);
Serial.printf("    Our MAC: %02X:%02X:%02X:%02X:%02X:%02X\n", ourEthernetMAC[0], ourEthernetMAC[1], ourEthernetMAC[2], ourEthernetMAC[3], ourEthernetMAC[4], ourEthernetMAC[5]);

Sep

2023

Where does lwIP parse the Ethernet packet header?

The Ethernet packet header is parsed in ethernet_input() in lwip/src/netif/ethernet.c:

Sep

2023

What is the default esp_eth_update_input_path() handler function?

By default, esp-idf or the Arduino framework handles incoming Ethernet packets using the

static esp_err_t eth_input_to_netif(esp_eth_handle_t eth_handle, uint8_t *buffer, uint32_t length, void *priv);

function in components/esp_eth/src/esp_eth_netif_glue.c which (besides calling just calls the exported functionesp_netif_receive():

static esp_err_t eth_input_to_netif(esp_eth_handle_t eth_handle, uint8_t *buffer, uint32_t length, void *priv)
{
    return esp_netif_receive((esp_netif_t *)priv, buffer, length, NULL);
}

The function esp_netif_receive() is declared in esp_netif.h and implemented in esp_netif_lwip.c.

This function will call esp_netif->lwip_input_fn(...) on the packet, which will in turn call the interface-type specific .input_fn(...), which is one of

or for wrapped interfaces:

esp_netif_lwip_slip_input
esp_netif_lwip_ppp_input

Aug

2023

NodeJS TCP ping example (Typescript)

The following Typescript example allows you to “ping” an IP address or host name not using ICMP but using TCP connection to a given port. If the TCP connection is accepted, the ping is resolved as true. If no connection can be established, it is returned as false. In any case, no data is exchanged and the connection is closed immediately after establishing it.

import { Socket } from "net";

/**
 * Basic TCP ping that returns true if the connection is successful, false if it fails
 * The socket is closed after the connection attempt, no data is exchanged.
 */
export function TCPConnectPing(ipAddress, timeout=5000, port=80): Promise<boolean> {
    return new Promise((resolve) => {
      const socket = new Socket();
      let connected = false;
  
      // Set a timeout for the connection attempt
      const timer = setTimeout(() => {
        if (!connected) {
          socket.destroy();
          resolve(false); // Connection timed out
        }
      }, timeout);
  
      socket.connect(port, ipAddress, () => {
        clearTimeout(timer);
        connected = true;
        socket.destroy();
        resolve(true); // Connection successful
      });
  
      socket.on('error', (error) => {
        clearTimeout(timer);
        if (!connected) {
          resolve(false); // Connection failed due to error
        }
      });
    });
  }

Jun

2023

VirtualHere USB server & systemd autostart on x86_64 in 25 seconds

The following script will download the VirtualHere USB server for the x86_64 called vhusbd.service.

#!/bin/bash
# This script installs and enables/starts the VirtualHere USB server
wget -O /usr/bin/vhusbd https://www.virtualhere.com/sites/default/files/usbserver/vhusbdx86_64
chmod a+x /usr/bin/vhusbd

cat >/etc/systemd/system/vhusbd.service <<EOF
[Unit]
Description=vhusbd
After=network-online.target

[Service]
Restart=always
User=root
Group=root
ExecStart=/usr/bin/vhusbd

[Install]
WantedBy=multi-user.target
EOF

# Enable and start service
systemctl enable --now vhusbd.service

Jun

2023

Cross-compiling boost for OpenWRT

This post showcases how to cross-compile boost for OpenWRT. We’ll use the Teltonika RUTX10 SDK which is already pre-configured with the relevant OpenWRT settings for that router.

The prerequisite for this is that you have:

Downloaded the SDK
Built it using our instructions or the official manual if you prefer a longer read.

We assume the SDK is located in ~/rutos-ipq40xx-rutx-gpl.

Compiling boost

First, you need to consider that many boost libraries are header-only libraries. For those libraries, you don’t need to compile boost, but it might still be easier to prepare a complete boost folder for installation.

First, download boost and unpack it. Now run

./bootstrap.sh

to compile bjam.

Now, open project-config.jam inside the boost folder and add the following line at the top of the file:

using gcc : openwrt : arm-openwrt-linux-muslgnueabi-g++ ;

Now, inside the boost folder, run the following bash script:

export STAGING_DIR=~/rutos-ipq40xx-rutx-gpl/staging_dir
export TOOLCHAIN=${STAGING_DIR}/toolchain-arm_cortex-a7+neon-vfpv4_gcc-8.4.0_musl_eabi
export CC=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-gcc
export CPP=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-g++
export PATH=$PATH:${TOOLCHAIN}/bin/

# Insert at the top of project-config.jam
# using gcc : openwrt : arm-openwrt-linux-muslgnueabi-g++ ;

rm -rf ~/boost_rutx10
mkdir -p ~/boost_rutx10/
./b2 --prefix=$HOME/boost_rutx10 install toolset=gcc-openwrt -sNO_COMPRESSION=1

Now, boost is installed in ~/boost_rutx10, which has include and lib subdirectories.

Jun

2023

How to build the Teltonika RUTX10 SDK in 5 minutes

Download the SDK from the relevant router’s page, e.g. RUTX10 firmware downloads
Unpack it
```
./scripts/feeds update -a
```
```
make -i
```
Wait until finished (it will typically take 30 minutes or so, depending on the computer.

May

2023

Does MikroTik RouterOS support secp384r1 certificates

Yes, RouterOS 7.9+ supports certificates with secp384r1 keys.

RouterOS versions before 7.9 possibly also support secp384r1 certificates but I have no older RouterOS available for testing at the moment.

May

2023

NodeJS MikroTik PoE status query example

This example builds on our previous posts NodeJS Mikrotik API minimal example and MikroTik RouterOS: How to power-cycle PoE using the terminal.

The following code will print the PoE status on Port ether5 on the given MikroTik device using the MikroTik API.

import * as MikroNode from 'mikrotik' ;

const host = "192.168.88.1";
const username = "admin";
const password = "admin1234"; // Hope that's not your real password ;)

const connection = MikroNode.getConnection(host, username, password, {
    closeOnDone : true
});

connection.getConnectPromise().then(function(conn) {
    conn.getCommandPromise(['/interface/ethernet/poe/print', '?name=ether5']).then(values => {
        console.log(values);
    }, reason => {
        console.log('Error while running command: ' + JSON.stringify(reason));
    });
}).catch(reason =>  {
    console.log('Error while connecting: ' + JSON.stringify(reason));
});

Example output:

[
  {
    '.id': '*5',
    name: 'ether5',
    'poe-out': 'forced-on',
    'poe-priority': '10',
    'poe-lldp-enabled': 'false',
    'power-cycle-ping-enabled': 'false',
    'power-cycle-interval': 'none',
    '.about': 'poe-out status: power_reset'
  }
]

If the PoE is currently being power-cycled, this will print:

[
  {
    '.id': '*5',
    name: 'ether5',
    'poe-out': 'forced-on',
    'poe-priority': '10',
    'poe-lldp-enabled': 'false',
    'power-cycle-ping-enabled': 'false',
    'power-cycle-interval': 'none',
    '.about': 'poe-out status: power_reset'
  }
]

May

2023

MikroTik RouterOS: How to power-cycle PoE using the terminal

/interface/ethernet/poe/power-cycle ether-MyAccessPoint duration=5

May

2023

NodeJS Mikrotik API minimal example

This is an example of access the Mikrotik API using NodeJS and the mikrotik package.

First, install the package

npm i --save mikrotik

Also, in order to enable import statement, set

"type": "module"

in package.json.

Example code:

import * as MikroNode from 'mikrotik' ;

const host = "10.56.23.4";
const username = "admin";
const password = "N@CdVTz8y@D$KwVS5TTo"; // Hope that's not your real password ;)

const  connection = MikroNode.getConnection(host, username, password, {
    closeOnDone : true
});

connection.getConnectPromise().then(function(conn) {
    conn.getCommandPromise('/ip/address/print').then(addresses => {
        for(const address of addresses) {
            console.info(`Address: ${address.address} on ${address.interface}`);
        }
    }, reason => {
        console.log('Error while running command: ' + JSON.stringify(reason));
    });
}).catch(reason =>  {
    console.log('Error while connecting: ' + JSON.stringify(reason));
});

This will output, for example:

Address: 192.168.88.1/24 on bridge
Address: 10.1.2.3/24 on bridge

In case of bad username/password credentials, it will print:

Error while connecting: {"errors":[{"category":"","message":"invalid user name or password (6)"}],"channelId":"login","channel":{"id":"login","running":true,"closing":true,"closed":true,"clearEvents":false,"saveBuffer":true,"closeOnDone":false,"lastCommand":["/login","=name=admin","=password=admin1234",".tag=login"],"_events":{},"_eventsCount":0}}

May

2023

Joplin default username / password

The default credentials for the Joplin note app are:

Username: admin@localhost
Password: admin

Source: Server README on Github

May

2023

How to fix MikroTik “Couldn’t add new IPv6 Pool – prefix length cannot be smaller than prefix (6)”?

Problem:

You are trying to add a new IPv6 pool with settings such as

But when you click OK, you see an error message Couldn't add new IPv6 Pool - prefix length cannot be smaller than prefix (6)

Solution:

You need to add the prefix length – e.g. /64 to the Prefix field as well:

Now click OK or apply and the error will disappear.

Important note: You might want to use a different Prefix Length here (typically it is smaller than the e.g. /64 at the end of the Prefix field so multiple prefixes can be extracted from the given pool.

May

2023

Where to find public domain “Ethernet” / “Network port” icon?

This one on Wikimedia commons is public domain by @CompanyDude and available as SVG:

May

2023

Where is the mosquitto persistence DB located by default?

By default, mosquitto saves persistence data in mosquitto.db

Source: mosquitto manpage

Apr

2023

How to monitor storj storage node satellite exit status using docker-compose

First try

docker-compose exec storagenode /app/storagenode exit-status --identity.cert-path /app/identity/identity.cert --identity.key-path /app/identity/identity.key

or for older storj versions use

docker-compose exec storagenode /app/storagenode exit-status --identity-dir /app/identity

Apr

2023

How to cross-compile native C++ executable for Teltonika RUTX10 / RUTX11

First, download the pre-configure OpenWRT buildroot from Teltonika.

Unzip it:

tar xzvf RUTX_R_GPL_00.07.04.1.tar.gz
cd rutos-ipq40xx-rutx-gpl/

and now build using

./scripts/feeds update -a
make -i

This will build not only the toolchain but also all packages etc, hence it will take a while.

Now create main.cpp, e.g.:

#include <iostream>

int main(int argc, char** argv) {
    std::cout << "Hello World!" <<std::endl;
}

The build script build.sh looks like this:

#!/bin/sh
export STAGING_DIR=~/rutos-ipq40xx-rutx-gpl/staging_dir
export TOOLCHAIN=${STAGING_DIR}/toolchain-arm_cortex-a7+neon-vfpv4_gcc-8.4.0_musl_eabi
export CC=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-gcc
export CPP=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-g++

# Build !
${CPP} -o main main.cpp

This will produce main , an executable which you can copy to and run on your RUTX10.

Networking

Where to find cheap RJ45 connectors

With magnetics:

No magnetics:

How to access RouterOS API in Python using the ‘routeros’ library (minimal example)

Netmiko MikroTik RouterOS SSH key login example

Example output:

How to parse Ethernet packet header (src & dst MAC addresses) using lwIP

Where does lwIP parse the Ethernet packet header?

What is the default esp_eth_update_input_path() handler function?

NodeJS TCP ping example (Typescript)

VirtualHere USB server & systemd autostart on x86_64 in 25 seconds

Cross-compiling boost for OpenWRT

Compiling boost

How to build the Teltonika RUTX10 SDK in 5 minutes

Does MikroTik RouterOS support secp384r1 certificates

NodeJS MikroTik PoE status query example

Example output:

MikroTik RouterOS: How to power-cycle PoE using the terminal

NodeJS Mikrotik API minimal example

Example code:

Joplin default username / password

How to fix MikroTik “Couldn’t add new IPv6 Pool – prefix length cannot be smaller than prefix (6)”?

Problem:

Solution:

Where to find public domain “Ethernet” / “Network port” icon?

Where is the mosquitto persistence DB located by default?

How to monitor storj storage node satellite exit status using docker-compose

How to cross-compile native C++ executable for Teltonika RUTX10 / RUTX11

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