Programmatically detect network connectivity in Windows (C++) - c++

I need to detect when the Windows system is connected to/disconnected from network (LAN or WLAN) in C++ and without using WMI.
I have found a way to do this for wireless networks. (I have answered my own question here after finding a way), but this does not work (obviously) when I connect/disconnect a LAN cable.
How can I detect a change in network connection when user has connected a LAN cable to his Windows system? Is there a general way (instead of having separate code for WLAN and LAN) to find this?
Note: The network may or may not be connected to the internet.

Related

Listen to UDP broadcast from a Ubuntu docker-container on Windows host

I have a C++ application that records the data from an external camera sensor. The sensor sends out UDP packets and it has it's own API. The API automatically scans the subnet and connects to the camera sensor. I know the IP address of the camera but there is no possibility to specify it manually using this API.
Unfortunately, I must use a Windows host machine to use my CPP application. I use CPP libraries that are only available for linux. Therefore I am constrained to use linux in a docker container on the Windows host. The camera API does not automatically find the device because it is not on the same subnet. The host network feature in docker would have solved this issue but it is not available on Windows.
Has someone been in a similar situation? or Can someone explain me how to get around this problem? I do not have much knowledge of networking.

Application specific network interface in CEF3 based application

I am writing a CEF3 based application. I have a requirement, where I can show available network interface and select any of them. Once I have selected the network interface all the traffic should route through that selected network interface. For example if I am having one Ethernet one wifi and one 3G network interface available in my system. and all communication is going through the default which is Ethernet. Now If I select wifi from the application, All communication within the application should go through wifi.
I searched a lot over net and figured out that using bind() function we can bind a specific IP address for communication. But, How can I achieve it in CEF3?
I am new to CEF3 and never written any networking software.
I have already gone through below links-
Using a specific network interface for a socket in windows
https://www.raymond.cc/blog/bind-windows-application-to-specific-network-adapter-with-forcebindip/
TCP/IP connection on a specific interface
I am writing cef3 application in win32/c++ so looking for the same.

Detect devices on local network for client-server connection in C++

I'm trying to implement an auto-connect feature for my Android application DroidPad, which is basically a TCP server running on an Android phone which the PC application connects to.
To make the process easier for the user, is there any way in (portable?) C++ to scan the IP addresses on the local subnet, possibly ones with a certain open port? I've tried using UDP broadcasting, but couldn't get it to work. I'm currently using the wxWidgets toolkit for GUI and libraries.
Any ideas?
I found a solution: wxServDisc. It uses mDNS (aka Zeroconf / Bonjour) to discover devices on a subnet, and is also based on wxWidgets.

How to acess COM port of remote system?

I Want to access the COM port present in the remote system from system. Any help would be appreciable.
I am using windows XP in both remote as well as local system.
The com0com project, and especially the com2tcp application should help you.
In conjunction with the Null-modem
emulator (com0com) the com2tcp enables
to use a COM port based applications
to communicate with the TCP/IP based
applications. It also allows
communication with a remote serial
port via the TCP/IP.
Personally, I use SerProxy, which makes that com port looks like telnet:
Serproxy is a multi-threaded proxy program for redirecting network socket connections to/from serial links, in cases where the remote end of the serial link doesn't have a TCP/IP stack (eg an embedded or microcontroller system). The proxy allows other hosts on the network to communicate with the system on the remote end of the serial link.
I also looked into com0com before, but I finally decide not to use it, as it requires a driver installation. Where as serproxy just need to be run. Another nice part is that if the com port is not being "used" remotely, I can still access it locally.
I've used Advanced Virtual COM Port to share a COM port remotely.
On the local PC, it creates a virtual COM port that mirrors the activity of a real COM port on the remote PC. The remote PC can be on a local network or on the Internet. (If on the Internet, you just have to make sure your firewalls allow the particular TCP ports through.)
I tried several programs to share a COM port remotely, but this was the only one I found that also shared the serial hardware handshaking signals. So we picked this one, and it worked great. We used it about 3 years ago, to access a Japanese CDMA modem dev board, sitting in Japan, from Australia.

Detect When Network Cable Unplugged

Windows knows when you have removed the network cable from your NIC. Is there a programmatic way to determine this via API in C++?
Note: I am not using .NET and this is for a closed LAN (not connected to Internet ever)
Raymond Chen blogged about something similar recently. Here is the relevant documentation. I think the MIB_IPADDR_DISCONNECTED flag is what you are looking for.
Use the Network List Manager api with the INetwork api.
You can register your app to receive callbacks when networks become connected/not connected.
Or you can get the list of networks and then check each of them to see if the machine is network connected or not
Remember that a windows machine will often have multiple networks set up (Ethernet, wifi, etc)
Remember that just because a network is connected, you may not have access to the internet. Eg you could have DNS or routing problems. Or you could be on a working network that is not connected to the internet.
Due to the above, many diagnostic tools also connect to a "known-good" internet server if they want to really know if they're connected or not. Something like google.com -- they spend a lot of money to make sure that their site is up all the time.
Finally, you can also have a semi-connected situation where packets are getting through but not enough to really enable communications to flow. To test this, don't just ping an internet site since that'd only be a pair of packets. Instead, open a TCP connection or something more than a ping.