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An application that utilizes fast AF_XDP Linux sockets to generate and send network packets. Used for penetration testing including Denial of Service (DoS) and network monitoring. Made by @gamemann!

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Packet Batch AF_XDP Build Workflow Packet Batch AF_XDP Run Workflow

Packet Batch is a collection of high-performance applications and tools designed for generating and sending network packets. It serves two main purposes: penetration testing, which involves assessing network security by simulating various attacks like Denial of Service (DoS); and network monitoring, which involves analyzing and inspecting network traffic.

Features

  • The ability to send multiple network packets in a chain via sequences and multiple payloads inside of a single sequence coming from the same source.
  • Support for sending from randomized source IPs within range(s) indicated by CIDR.
  • Support for randomized payload data within a specific range in length.
  • UDP, TCP, and ICMP layer 4 protocols supported.
  • Optional layer 3 and 4 checksum calculation in the event you want the NIC's hardware to calculate checksums for generated outgoing packets.

Note Regarding Seeding/Randomness

When generating randomness in a packet (e.g. random source IPs, ports, payload(s), etc.), by default, we try to use nanoseconds since boot using timespec as the seed when passing to rand_r() for example. However, I've found this isn't completely random, especially since the seed variable (unsigned int) and timespec nanoseconds variable (long) do not match in size.

Therefore, I added the constant VERY_RANDOM that can be uncommented. When this constant is defined, the getrandom() function is used to fill the seed with random bytes. This results in more randomness, but the getrandom() function adds a bit more overhead than retrieving the nanoseconds since system boot from my testing.

Disclaimer

I do NOT support using these tools maliciously or as a part of a targeted attack. I've made these tools to perform penetration tests against my own firewalls along with occasionally debugging network issues such as packets not arriving to their destination correctly.

Showcase

These are just a couple of basic tests I performed between two virtual machines on my home server.

Test One

Test Two

NOTE - Since the above demos, there was a change in Packet Batch that allows for more precise/randomized IPs/ports via seeding here (using the seed, nanoseconds since boot, instead of the UNIX timestamp which is shown above). Therefore, Packet Batch will now send from a more randomized IP/port than what is shown above!

AF_XDP

This is a special version of Packet Batch that utilizes AF_XDP sockets instead of AF_PACKETv3 (which is what the standard version uses). I recommend using this version over the standard version due to performance improvements, but you must keep in mind the following.

  1. AF_XDP sockets require a more recent Linux kernel.
  2. The TCP cooked and oneconnection settings are NOT available in this version due to no cooked sockets support in AF_XDP.

The above is why we aren't utilizing AF_XDP sockets in the standard version.

From the benchmarks I've concluded on my home server running Proxmox VMs, AF_XDP sockets send around 5 - 10% more packets per second than the standard version and the amount of packets per second it is sending is a lot more consistent (regardless of the batch size option explained below). I won't have solid benchmarks until I perform these tests on full dedicated hardware which should happen in early 2022.

Building And Installing

Building and installing this project is fairly easy and just like the standard version. It includes building the Packet Batch Common repository which requires JSON-C. As long as you use the --recursive flag with git, it should retrieve all of the required submodules automatically located in the modules/ directory. Otherwise, you will need to go into the Common repository and execute the git submodule update --init command. We use make to build and install the application.

The following commands should work for Ubuntu/Debian-based systems. However, you should be able to install this on other Linux distros with a few adjustments as well.

# Update apt.
sudo apt update

# Install Git if it isn't already installed.
sudo apt install -y git

# Clone this repository along with its submodules.
git clone --recursive https://github.com/Packet-Batch/PB-AF-XDP.git

# Install build essentials/tools and needed libaries for JSON-C.
sudo apt install -y build-essential clang cmake pkgconf

# Install LibELF for BPF.
sudo apt install -y libelf-dev

# Change the current working directory to PB-AF-XDP/.
cd PB-AF-XDP/

# Execute ./build.sh file to build and install dependencies and main project which requires sudo privileges.
# WARNING - If you don't have sudo available on your system, please look at the ./build.sh file and execute make commands as root in order.
# NOTE - You may also look at the .github/workflows/build.yml.
# NOTE - The first argument represents the amount of threads to use with make. 0 uses the amount of available threads on the system and supplying no argument uses 1 thread.
./build.sh 0

# You may use the following to clean the build. You must run this as root or sudo because of the Common's cleanup.
sudo make clean

Install GIF

Installation Video!

Click here to watch!

Warning! - The installation video is a bit outdated, but should show most of the installation process. Since the video was made, we've switched to json-c from libyaml and use a build script to build the project and its dependencies (./build.sh).

After installing, the executable is copied to the /usr/bin/ directory which should be included in your $PATH. Therefore, you may use the application globally (in any directory).

For example.

pcktbatch -c /path/to/conf.json

Command Line Usage

Basic

Basic command line usage may be found below.

Usage: pcktbatch -c <configfile> [-v -h]

-c --cfg => Path to the config file.
-l --list => Print basic information about sequences.
-v --verbose => Provide verbose output.
-h --help => Print out help menu and exit program.

First Sequence Override

If you wanted to quickly send packets and don't want to create a config file, you may specify command line options to override the first sequence. You must also specify the -z or --cli flag in order to do this.

The following command line options are available to override the first sequence.

-z --cli => Enables the first sequence/packet override.

--interface => The interface to send out of.    --block => Whether to enable blocking mode (0/1).       --track => Track packet and byte statistics and print at the end (0/1). Will impact performance!
--maxpckts => The maximum amount of packets to send during this sequence before exiting.
--maxbytes => The maximum amount of bytes to send during this sequence before exiting.
--pps => The amount of packets per second to limit this sequence to (0 = disabled).
--bps => The amount of bytes per second to limit this sequence to (0 = disabled)
--delay => The delay in-between sending packets on each thread.
--threads => The amount of threads and sockets to spawn (0 = CPU count).
--l4csum => Whether to calculate the layer-4 checksum (TCP, UDP, and ICMP) (0/1).

--smac => The ethernet source MAC address to use.
--dmac => The ethernet destination MAC address to use.

--minttl => The minimum IP TTL to use.
--maxttl => The maximum IP TTL to use.
--minid => The minimum IP ID to use.
--maxid => The maximum IP ID to use.
--sip => The source IP (one range is supported in CIDR format).
--dip => The destination IP.
--protocol => The protocol to use (TCP, UDP, or ICMP).
--tos => The IP TOS to use.
--l3csum => Whether to calculate the IP header checksum or not (0/1).

--usport => The UDP source port.
--udport => The UDP destination port.

--tsport => The TCP source port.
--tdport => The TCP source port.
--syn => Set the TCP SYN flag (0/1).
--ack => Set the TCP ACK flag (0/1).
--psh => Set the TCP PSH flag (0/1).
--rst => Set the TCP RST flag (0/1).
--fin => Set the TCP FIN flag (0/1).
--urg => Set the TCP URG flag (0/1).
--ece => Set the TCP ECE flag (0/1).
--cwr => Set the TCP CWR flag (0/1).

--pmin => The minimum payload data.
--pmax => The maximum payload data.
--pstatic => Use static payload (0/1).
--pexact => The exact payload string.
--pfile => Whether to parse a file as the 'pexact' string instead.
--pstring => Parse the 'pexact' string or file as a string instead of hexadecimal.

AF_XDP

There is additional command line usage with the AF_XDP version which may be found below.

--queue => If set, all AF_XDP/XSK sockets are bound to this specific queue ID.
--nowakeup => If set, all AF_XDP/XSK sockets are bound without the wakeup flag.
--sharedumem => If set, all AF_XDP/XSK sockets use the same UMEM area.
--batchsize => How many packets to send at once (default 1).
--forceskb => If set, all AF_XDP/XSK sockets are bound using the SKB flag instead of DRV mode.
--zerocopy => If set, all AF_XDP/XSK sockets are attempted to be bound with zero copy mode.
--copy => If set, all AF_XDP/XSK sockets are bound with copy mode.

NOTE - The batch size indicates how many packets to send at the same time, but this is the same packet data. This may or may not speed up performance, but personally I didn't see much of an impact.

NOTE - By default, each socket is created in a separate thread specified in the config and is bound to a separate queue ID (incremented by 1). With that said, shared UMEM is not supported by default and each socket has its own UMEM area. The XDP wakeup flag is also specified by default which should improve performance.

Configuration File

If you want to use more than one sequence or more control, you will need to specify sequences inside of a config file using the JSON syntax.

Before continuing, here is information on the types used below with the config.

Name Length (Bytes) Unsigned Description
string N/A N/A A string terminated by \0.
byte 1 yes A single byte integer.
boolean 1 yes A single true (1) or false (0) value.
ushort 2 yes An unsigned short.
short 2 no A short.
uint 4 yes An unsigned integer.
int 4 no An integer.
ulong 8 yes An unsigned long.
long 8 no A long.

Here is the full config file format.

Key Type Default Description
interface string null The default interface to send packets out of.
sequences Array Sequence Object [] An array of sequences to use (see below).
Examples Basic config.
{
    "interface": "devint",
    "sequences": [
        {
            ...
        },
        {
            ...
        }
    ]
}

Sequence Object

The sequence object has the following fields.

Key Type Default Description
interface string null The interface to use when sending out of this sequence.
block boolean true Whether to block the main thread/other sequences until this sequence is completed.
track boolean false Tracks total packets/bytes including average per second for the sequence and prints before the program exits. This will impact performance!
maxpckts ulong 0 If above 0, the sequence will exit after hitting this amount of total packets sent.
maxbytes ulong 0 If above 0, the sequence will exit after hitting this amount of total bytes sent.
pps ulong 0 If above 0, will limit the sequence to this amount of packets per second.
bps ulong 0 If above 0, will limit the sequence to this amount of bytes per second.
time ulong 0 If above 0, will limit the sequence to this amount of time in seconds before exiting.
threads ushort 0 If 0, will spawn x amount of threads for this sequence. Otherwise, uses CPU count.
delay ulong 1000000 The delay between each iteration (sent packet) in the sequence in microseconds.
l4csum boolean true Whether to calculate the layer-4 checksum in the program.
eth Ethernet Object {} The ethernet header object (see below).
ip IP Object {} The IP header object (see below).
udp UDP Object {} The UDP header object (see below).
tcp TCP Object {} The TCP header object (see below).
icmp ICMP Object {} The ICMP header object (see below).
payloads Array Payload Object [] The payloads array (see below).
Examples

The following sends packets out of the dev interface. It blocks the thread and only runs for 20 seconds. There is a 100000 microsecond delay in-between sending packets on the main sequence.

{
    "interface": "dev",
    "block": true,
    "time": 20,
    "delay": 100000,
    "eth": {
        ...
    },
    "ip": {
        ...
    },
    "tcp": {
        ...
    },
    "udp": {
        ...
    },
    "icmp": {
        ...
    },
    "payloads": [
        ...
    ]
}

The following sends packets out of the dev interface. It blocks the thread and only runs until 3000 packets sent. there is no delay between sending packets, so it will send packets as fast as it can.

{
    "interface": "dev",
    "block": true,
    "maxpckts": 3000,
    "time": 0,
    "delay": 0,
    "eth": {
        ...
    },
    "ip": {
        ...
    },
    "tcp": {
        ...
    },
    "udp": {
        ...
    },
    "icmp": {
        ...
    },
    "payloads": [
        ...
    ]
}

The following sends packets out of the dev interface. It blocks the thread and runs until you hit CTRL + C or use another method to kill the process. The sequence is limited to sending 300 packets per second.

{
    "interface": "dev",
    "block": true,
    "pps": 300,
    "time": 0,
    "delay": 0,
    "eth": {
        ...
    },
    "ip": {
        ...
    },
    "tcp": {
        ...
    },
    "udp": {
        ...
    },
    "icmp": {
        ...
    },
    "payloads": [
        ...
    ]
}

Ethernet Object

The ethernet object contains the following fields.

Key Type Default Description
smac string null The source MAC address to use. If not set, will attempt to retrieve the source MAC address automatically.
dmac string null The destination MAC address to use. If not set, will attempt to retrieve the destination MAC address automatically via gateway.
Examples

The following sends packets from 09:EB:23:AB:2D:B1 to 08:EC:4B:23:F2:E3.

{
    "smac": "09:EB:23:AB:2D:B1",
    "dmac": "08:EC:4B:23:F2:E3"
}

IP Object

The IP object contains the following fields.

Key Type Default Description
sip string null The source IP to send from.
dip string null The destination IP to send to.
protocol string null The layer-4 protocol. Available options include tcp, udp, and icmp.
tos byte 0 The Type of Server (ToS) to use.
csum boolean true Whether to calculate the IP header checksum.
ttl TTL Object {} The TTL object (see below).
id ID Object {} The ID object (see below).
ranges Array String {} An array of IP ranges that should be in the <ip>/<cidr> format.
Examples

Here's an example that sends packets from 192.168.2.2 to 192.168.2.3. The protocol is TCP.

{
    "sip": "192.168.2.2",
    "dip": "192.168.2.3",
    "protocol": "tcp",
    "csum": true,
    "ttl": {
        ...
    },
    "id": {
        ...
    },
    "ranges": [
        ...
    ]
}

Here's another example that sends packets from random IPs within the 10.4.0.0/24 and 10.5.0.0/24 ranges to 10.3.0.2. The protocol used is UDP.

{
    "sip": null,
    "dip": "10.3.0.2",
    "protocol": "udp",
    "csum": true,
    "ranges": [
        "10.4.0.0/24",
        "10.5.0.0/24"
    ]
}
TTL Object

The TTL object contains the following fields.

Key Type Default Description
min byte 64 The minimum TTL to use.
max byte 64 The maximum TTL to use.
Examples

Here's an example of generating a TTL between 64 and 128 every time we generate a packet.

{
    "min": 64,
    "max": 128
}
ID Object

The ID object contains the following.

Key Type Default Description
min byte 0 The minimum ID to use.
max byte 64000 The maximum ID to use.
Examples

Here's an example of generating an ID between 4000 and 9000 every time we generate a packet.

{
    "min": 4000,
    "max": 9000
}

TCP Object

The TCP object contains the following fields.

Key Type Default Description
sport ushort 0 The TCP source port to use. If 0, will generate a random port.
dport ushort 0 The TCP destination port to use. If 0, will generate a random port.
syn boolean false Sets the TCP SYN flag.
psh boolean false Sets the TCP PSH flag.
fin boolean false Sets the TCP FIN flag.
ack boolean false Sets the TCP ACK flag.
rst boolean false Sets the TCP RST flag.
urg boolean false Sets the TCP URG flag.
ece boolean false Sets the TCP ECE flag.
cwr boolean false Sets the TCP CWR flag.
Examples

Here's an example of sending packets with the SYN flag set to port 80.

{
    "dport": 80,
    "syn": true
}

UDP Object

The UDP object contains the following.

Key Type Default Description
sport ushort 0 The UDP source port to use. If 0, will generate a random port.
dport ushort 0 The UDP destination port to use. If 0, will generate a random port.
Examples

Here's an example of sending packets from UDP source port 27005 to destination port 27015.

{
    "sport": 27005,
    "dport": 27015
}

ICMP Object

The ICMP object contains the following fields.

Key Type Default Description
code byte 0 The ICMP code to set.
type byte 0 The ICMP type to set.
Examples

Here's an example of sending an ICMP echo request (type 8 and code 0).

{
    "code": 0,
    "type": 8
}

Payload Object

The payload object contains the following fields.

Key Type Default Description
exact string null The exact payload in hexadecimal.
isstatic boolean false Whether the payload is static (shouldn't change). If exact isn't set, it will generate payload once and reuse that payload each time.
isfile boolean false Whether exact should act as the path to the file and read as is.
isstring boolean false Whether to parse exact as a string instead of hexadecimal.
length Length Object {} The length object (see below).
Examples

This example sends packets with the payload 0x01 0xFB 0x02 0xFC (4 bytes in payload size).

{
    "exact": "01 FB 02 FC"
}

This example sends packets with a random payload between 0 and 5 bytes.

{
    "length": {
        "min": 0,
        "max": 5
    }
}

This example parses ./mypayload.txt as hexadecimal and uses that as the payload.

{
    "exact": "./mypayload.txt",
    "isfile": true
}

This example parses GET / HTTP/1.0\r\nHost: 1.2.3.4\r\n\r\n as a string and uses that as the payload.

{
    "exact": "GET / HTTP/1.0\r\nHost: 1.2.3.4\r\n\r\n",
    "isstring": true
}
Length Object

The length object contains the following fields.

Key Type Default Description
min ushort 0 The minimum length.
max ushort 0 The maximum length.

If you are looking for full examples, please check out this repository.

NOTE - The default config path is /etc/pcktbatch/conf.json. This may be changed via the -c and --cfg flags as explained under the Command Line Usage section below.

Credits