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How to do same as 'nmap' command from within a D program?
Jan 22, 2022
Daren Scot Wilson
Jan 22, 2022
forkit
Jan 22, 2022
forkit
Jan 22, 2022
forkit
Jan 23, 2022
frame
Jan 24, 2022
Daren Scot Wilson
Jan 24, 2022
Adam D Ruppe
January 22, 2022
Gravatar of Daren Scot WilsonPosted by Daren Scot WilsonReply
Daren Scot Wilson
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I'm writing a command line program to control certain hardware devices. I can hardcode or have in a config file the IP addresses for the devices, if I know that info. If I don't? Then I run an 'nmap' command and look for the devices. But why should I, a human, have to do any work like that? Bah! I want my program to obtain this information at runtime, automatically, and "don't make me think".

One thing that might make it tough is nmap must run sudo to report the desired information. (To my knowledge; I'm no networking expert.) The exact command is:

sudo nmap -sn 192.168.11.0/24 |ack -B2 "Philips"

The IP address is printed two lines before the name match (ack is "better than grep"). Typical nmap output is a series of chunks of text like this:

Nmap scan report for 192.168.11.10
Host is up (0.00033s latency).
MAC Address: 00:17:88:4D:97:4D (Philips Lighting BV)

I don't see any D std.* libraries that do this. Are there a Dub packages I should look at?

January 22, 2022
Gravatar of forkitPosted by forkit
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forkit
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On Saturday, 22 January 2022 at 20:55:38 UTC, Daren Scot Wilson wrote:
>

is this helpful:

// ---
module test;

import std;

void main()
{
    auto result = execute(["bash", "-c", "nmap -sn 192.168.11.0/24 | ack -B2 \"Phillips\""]);

    if(canFind(result.to!string, "Host is up"))
        writeln("Host is up");
    else
        writeln("Host not found.");
}

// ---
January 22, 2022
Gravatar of forkitPosted by forkit
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forkit
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On Saturday, 22 January 2022 at 22:44:31 UTC, forkit wrote:
>

and here is how to get the ip (depending on the formatting of your output of course)

// ---
module test;

import std;

void main()
{
    auto result = execute(["bash", "-c", "nmap -sn 192.168.11.0/24 | ack -B2 \"Philips\""]);

    string ip;

    if(canFind(result.to!string, "Host is up"))
    {
        writeln("Host is up");

        string str = result.to!string.chop;
        ip = str[ (indexOf(str, "for Philips (") + 10)..$-4 ];
        writeln(ip);
    }
    else
        writeln("Host not found.");
}

// ----
January 22, 2022
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On Saturday, 22 January 2022 at 23:15:18 UTC, forkit wrote:
>

oh.. this is better i think...

ip = str[ ((lastIndexOf(str, "(")) + 1) .. lastIndexOf(str, ")") ];
January 23, 2022
Gravatar of framePosted by frame
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On Saturday, 22 January 2022 at 20:55:38 UTC, Daren Scot Wilson wrote:

>

I don't see any D std.* libraries that do this. Are there a Dub packages I should look at?

If you really want to this in D without any external app or OS API you could just ping all possible hosts, see which respond and then use getHostByAddr() to find the hostname.

Another more professional way is to query the ARP protocol, where you send a packet as broadcast to all interfaces in the network to find a MAC for a given IP - if any host responses with a MAC, the host is up.

You have to build the packet data for yourself, there are examples on the web. The socket to use is family:INET, type:RAW and protocol:ICMP for ping or RAW for ARP or anything that isn't listed in D.

As you can see, it's required to test every possible IP out (except for any other discovery protocols supported by your network/router). For this reason, any OS does this scan periodically and caches the result. On UNIX you can just directly read the file /proc/net/arp, no need to use nmap.

January 24, 2022
Gravatar of Daren Scot WilsonPosted by Daren Scot Wilson
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On Sunday, 23 January 2022 at 06:30:11 UTC, frame wrote:

>

On Saturday, 22 January 2022 at 20:55:38 UTC, Daren Scot Wilson wrote:

>

I don't see any D std.* libraries that do this. Are there a Dub packages I should look at?

If you really want to this in D without any external app or OS API you could just ping all possible hosts, see which respond and then use getHostByAddr() to find the hostname.

Another more professional way is to query the ARP protocol, where you send a packet as broadcast to all interfaces in the network to find a MAC for a given IP - if any host responses with a MAC, the host is up.

You have to build the packet data for yourself, there are examples on the web. The socket to use is family:INET, type:RAW and protocol:ICMP for ping or RAW for ARP or anything that isn't listed in D.

As you can see, it's required to test every possible IP out (except for any other discovery protocols supported by your network/router). For this reason, any OS does this scan periodically and caches the result. On UNIX you can just directly read the file /proc/net/arp, no need to use nmap.

I'll try this. Looks more educational. This is a personal project, a show-off project. Once I'm done with another portion of it, I'll get onto this. My program will need to scan only once, not even once per run, since I can stash the results in a config file, but once whenever the user knows the hardware devices have changed.

January 24, 2022
Gravatar of Adam D RuppePosted by Adam D Ruppe
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Adam D Ruppe
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On Saturday, 22 January 2022 at 20:55:38 UTC, Daren Scot Wilson wrote:
> I'm writing a command line program to control certain hardware devices. I can hardcode or have in a config file the IP addresses for the devices, if I know that info. If I don't?

Depending on the hardware, you might be able to send a broadcast packet and listen to replies too.

The nmap command you do just does pings to each address in that range (btw I actually wrote a little module to turn one of those ranges into a bunch of ip address strings: https://github.com/adamdruppe/arsd/blob/master/cidr.d ). The stdlib doesn't have a convenient ping function though.

But yah depending on the hardware you might be able to do udp broadcasts and such. I had this led tower light thing for a client I had to set up and that's what i did there - udp broadcast a config packet, get the list of all the mac addresses, send config packets to change their ips, and get going.