user2896215 user2896215 - 1 year ago 87
Perl Question

Using Perl's Net::Frame::Simple module to rewrite ethernet header

I am using below code (copied from to rewrite the ethernet src and dst mac information but its generating bad IP packet.


use Net::Frame::Simple;
use Net::Frame::Layer::IPv4;
use Net::Frame::Layer::TCP;
use Net::Frame::Layer::ETH;
use Net::Frame::Device;
use Net::Write::Layer3;
use Net::Frame::Dump::Online;
use Net::Write::Layer2;

my $src = '';
my $target = '';
my $port = 22;

my $eth = Net::Frame::Layer::ETH->new(src => "00:0c:29:d1:03:06", dst => "03:03:03:03:03:03");
my $ip4 = Net::Frame::Layer::IPv4->new(src => $src,dst => $target);
my $tcp = Net::Frame::Layer::TCP->new(dst => $port, options => "\x02\x04\x54\x0b",payload => 'test');

my $oSimple = Net::Frame::Simple->new(layers => [$eth,$ip4,$tcp],);

# Now, the frame is ready to be send to the network
# We open a sender object, and a retriever object

my $oWrite = Net::Write::Layer2->new(dev => 'eth0');
$oWrite = Net::Write::Layer3->new(dst => $target);
#my $oDump = Net::Frame::Dump::Online->new(dev => $oDevice->dev);

# We send the frame

If i remove the ethernet part ($eth) when defining layers in $oSimple, it works.
Any suggestions what i am missing or doing wrong?

Answer Source

I was able to make it work For anyone's reference, if remove the line "Net::Write::Layer3" and just do the writing at layer 2 (Net::Write::Layer2) in above code, you can change the src and dst MACs.

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