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socket-connect-bpf

socket-connect-bpf is a Linux command line utility that writes human-readable information about each application that makes new (network) connections to the standard output.

socket-connect-bpf while making a request with curl

More sample output.

Details

socket-connect-bpf is a BPF/eBPF prototype with a kernel probe attached to security_socket_connect. Connections to AF_UNSPEC and AF_UNIX are explicitly excluded.

Following information about each request is displayed if possible:

Name	Description	Sample
Time	Time at which the connection event was received.	`17:15:58`
AF	Address family	`AF_INET`
PID	Process ID of the process making the request.	`8549`
Process	Process path/args of the process making the request.	`/usr/bin/curl`
User	Username under which the process is executed.	`root`
Destination	IP address and port of the destination.	`127.0.0.1 53`
AS-Info	Info about the autonomous system (AS) of the IP address.	`AS36459 (GITHUB)`

Use cases

You might want to try socket-connect-bpf for the following use cases:

Check if an application contains analytics.
Check if your trusted dependencies communicate with the outside world.
As a less invasive alternative to Kernel modules that provide the same functionality.

License

The socket-connect-bpf Go code is licensed under the Apache License. The BPF code is licensed under GPL as some BPF-helpers are GPL-only.

System requirements

x64/amd64 or AArch64/arm64 CPU
Linux Kernel: 4.18 or later

Installation

Install binaries (Version 0.4.0 or later)

Tested on following architecures:

amd64 (Intel x64 CPU)
arm64 (AWS Graviton2/Arm Neoverse-N1)

Instructions tested on Debian Bookworm with Linux Kernel 6.5:

Extract the corresponding socket-connect-bpf-*.tar.gz release.

Verify binaries (Version 0.4.0 or later)

Tarballs can be verified with minisign and following public key:

RWRUqB/iFRENms4B2LbOrNGizwXbStkIPE8sUq01r63cXJP8kzHp+ITv

Running:

sudo ./socket-connect-bpf

Print all

Print all -a also prints the process arguments and the AS information.

sudo ./socket-connect-bpf -a

Autonomous System (AS) Information

Information about an autonomous system (AS) that an IP address belongs to is not displayed by default. It can be turned on with the print all flag -a.

sudo ./socket-connect-bpf -a

AS data

AS data of IPtoASN is used. The local AS-Number lookup will require some more RAM.

To update the AS data used while developing run:

./updateASData.sh

Development

Build code from repository

Step-by-Step instructions for Debian Bookworm with Linux Kernel 6.5.0.

# Install Go 1.22 or later (if not already installed)
sudo snap install --classic go

# Install Clang 16 (for compiling the BPF sources)
sudo apt install clang-16

# Change into a folder of your choice and clone socket-connect-bpf
git clone https://github.com/p-/socket-connect-bpf.git

cd socket-connect-bpf

go generate
go build

Tests

Run tests:

go test ./...

IDE

VS Code or any other Go Lang IDE can be used for development.