sockets.py

import socket

from typing import Final

ETH_P_ALL: Final[int] = 3

RECV_SIZE: Final[int] = 65536


def make_raw_socket() -> socket.socket:
    """Makes a socket that abstracts away nothing."""
    return socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(ETH_P_ALL))


def make_ethernet_socket(proto: int = socket.IPPROTO_RAW) -> socket.socket:
    """Makes a socket that abstracts away the ethernet layer."""
    result: socket.socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, proto)
    result.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
    return result


def make_ip_socket() -> socket.socket:
    """Makes a socket that abstracts away the IP layer."""
    return socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)


def flush_socket(s: socket.socket) -> None:
    """
    Removes everything in the socket buffer from before this function was called.
    There is no guarantee that data received during the execution of this function
    will be flushed, so there is no guarantee that the socket is empty after the
    execution of this function.
    """
    orig_timeout: float | None = s.gettimeout()
    s.settimeout(0.0)
    while True:
        try:
            s.recv(RECV_SIZE)
        except BlockingIOError:
            break
    s.settimeout(orig_timeout)