Re: Net::RawIP - invalid checksum ?

Not sure what you're trying to do - other than create custom UDP packets. If that's the only requirement, you can try the Perl Packet Crafter. It's a shell similar to 'scapy' but this is the Perl version based on the Net::Frame modules.

Find it here:

Script: http://www.vinsworld.com/software/ppc.zip
Perldoc: http://www.vinsworld.com/software/ppc.html

You'll need to get Net::Pcap running if you don't already have it going. Once all prereq's are installed, it's as easy as:

VinsWorldcom@C:\Users\VinsWorldcom\tmp\ppc> ppc -i "Wireless Network C
+onnection"
Welcome to Perl Packet Crafter (PPC)
Copyright (C) Michael Vincent 2012

Wireless Network Connection

ppc> sendp packet ETHER,IPv4(src=>'192.168.10.10',dst=>'192.168.10.20'
+,protocol=>NF_IPv4_PROTOCOL_UDP),UDP(src=>6544,dst=>514,payload=>'tes
+t123');
.
Sent 1 packet


ppc>
[download]

And tcpdump verfies:

VinsWorldcom@C:\Users\VinsWorldcom> tcpdump -i4 -nevvXX udp port 514
tcpdump: listening on \Device\NPF_{731EA781-5FB3-4C71-944A-D70C7EE18AA
+7}
21:00:28.058467 c0:cb:38:08:46:76 > 58:6d:8f:78:ad:40, ethertype IPv4 
+(0x0800),
length 49: (tos 0x0, ttl 128, id 56403, offset 0, flags [none], proto:
+ UDP (17),
 length: 35) 192.168.10.10.6544 > 192.168.10.20.514: [udp sum ok] [|sy
+slog]
        0x0000:  586d 8f78 ad40 c0cb 3808 4676 0800 4500  Xm.x.@..8.Fv
+..E.
        0x0010:  0023 dc53 0000 8011 c907 c0a8 0a0a c0a8  .#.S........
+....
        0x0020:  0a14 1990 0202 000f 02c3 7465 7374 3132  ..........te
+st12
        0x0030:  33                                       3

1 packets captured
28 packets received by filter
0 packets dropped by kernel
[download]

And note if you're actually trying to send Syslog, there is a Net::Frame::Layer::Syslog module for that.

Comment on Re: Net::RawIP - invalid checksum ? Select or Download Code

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Re^2: Net::RawIP - invalid checksum ? by willambender (Initiate) on Dec 07, 2013 at 02:28 UTC
Cool. Thanks for the info, i'll look into those. Yeah, what im working on is forwarding/creating syslog messages for a project. I have working code in C and wanted to port it over to perl as well. I started looking at using perl Socket but was sidetracked to Net::RawIP when i read it calculated the checksums for ya. Thou, it's looking like that this is not the case? - Will	[reply]
Re^3: Net::RawIP - invalid checksum ? by VinsWorldcom (Prior) on Dec 07, 2013 at 11:42 UTC
If you're looking to send Syslog, you don't need to craft custom UDP packets. You can use IO::Socket to create TCP and UDP packets without worrying about checksum calculation - it's done for you by the OS IP/socket stack. For Syslog specifically, just use Net::Syslog. You don't even need to worry about sockets with that - it's done behind the scenes. If you need to listen to / receive Syslog messages, have a look at Net::Syslogd.	[reply]