beeper 0.1.2

# Beeper: Application-Layer Parsing in eBPF

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[doi-url]: https://doi.org/10.48550/arXiv.2605.31084

Beeper (BEEline's ParsER) is an application-layer parser for eBPF. It allows you to process L7 protocols directly in the kernel, which can accelerate user space applications significantly. It achieves this by constructing an Aho-Corasick-like DFA in user space, reducing the parsing complexity to an eBPF-compatible level. With Beeper, you can for example monitor application-layer traffic, redirect it based on its payload, or respond to it, directly from the kernel. For more information, please have a look at the [full paper][doi-url].

Protocol      | Status  | Minimal Kernel Version
------------- | ------- | ----------------------
HTTP/1.1      | ✅      | 6.8
HTTP/2        | ✅      | 6.8
gRPC          | WIP     | 

## Usage

First, in the Rust program, create a new parser instance, add the desired headers that it should parse, and attach it to an existing eBPF program:
```rust
use beeper::h2;

let h2 = h2::Parser::new()
    .capture_hdr(&beeper::header::PATH)?
    .capture_hdr(&http::header::CONTENT_LENGTH)?
    .replace_parse_msg("parse_h2")
    .replace_extract("extract_h2_match")
    .attach(prog_fd)?;
```

Next, in your eBPF program, import the `beeper.h` header, define the stub functions, and call them with the input buffer:
```c
#include "beeper.h"

// stub funcs
BEEPER_EXTRACT_MATCH(extract_h2_match)
BEEPER_H2_PARSE_MSG(parse_h2)

// the header matches occur in the same order as configured in user space
#define H2_PATH_MID 0
#define H2_CONTENT_LENGTH_MID 1

SEC("sk_msg")
int msg_verdict(struct sk_msg_md *msg) {
    struct parse_res pres = { 0 };
    struct h2_frame frame = { 0 };
    int msg_len = parse_h2(msg, &pres, &frame);
    if (msg_len >= 0) {
        struct hdr_str path = { 0 };
        if (extract_h2_match(msg, &pres, H2_PATH_MID, &path) == 0) {
            // note that path can be Huffman-encoded
        }
    }
}
```

Finally, to make this all compile, Beeper relies on [xbpf](https://github.com/lerboe/xbpf). Add the following to `build.rs`:
```rust
use beeper::build::clang_args;
use xbpf::build::Builder;

fn main() {
    Builder::new()
        .clang_arg(clang_args().iter())
        .export_headers()
        .build();
}
```

Please refer to the [example](example) for the full code.

## Build

To build and test Beeper, you need to install the following packages:

```bash
sudo apt install clang-18 llvm-18 libelf-dev zlib1g-dev linux-headers-`uname -r` linux-tools-`uname -r` 
```

You should now be able to compile and test Beeper as follows:

```bash
RUST_LOG=trace cargo test
```

## Running the Example

Once you can build Beeper, you can also run the example. It is a simple HTTP server, with Beeper attached to it. It will serve some static files directly from the kernel. To run it, first start the server:
```bash
cargo run --bin example
```

Then, in another terminal, make a request to the server:
```bash
curl -vv http://127.0.0.1:8080/index.html
```

In the logs of the server, you should find a line that indicates that the request was served directly from the kernel:
```
Served request
```

To benchmark the server, run the following:
```bash
# server accelerated with beeper
RUST_LOG= cargo run -r --bin example
# baseline: server without the fastpath
RUST_LOG= cargo run -r --bin example -- --no-fastpath
```

In a new window, you can now run the load test:
```bash
cargo install oha

# to test http1 performance
oha -c 100 -q 1000 -z 30s --latency-correction --urls-from-file example/load.txt
# to test http2 performance
oha -c 100 -q 1000 -z 30s --http2 --latency-correction --urls-from-file example/load.txt
```

## Citation

If you use this library to conduct your own research, please cite the full paper as follows:
```
@misc{beeline,
      title={Enforcing Application-Layer Policies in eBPF}, 
      author={Laurin Brandner and Ayush Mishra and Sebastiano Miano and Aurojit Panda and Gianni Antichi and Laurent Vanbever},
      year={2026},
      eprint={2605.31084},
      archivePrefix={arXiv},
      primaryClass={cs.NI},
      url={https://arxiv.org/abs/2605.31084}, 
}
```