| #!/usr/bin/env python3 | |
| # SPDX-License-Identifier: GPL-2.0 | |
| """ | |
| tdc_gso.py - send a UDP GSO datagram | |
| Copyright (C) 2026 Xingquan Liu <b1n@b1n.io> | |
| """ | |
| import argparse | |
| import socket | |
| import struct | |
| import sys | |
| UDP_MAX_SEGMENTS = 1 << 7 | |
| parser = argparse.ArgumentParser(description="UDP GSO datagram sender") | |
| parser.add_argument("src", help="source IPv4 address") | |
| parser.add_argument("dst", help="destination IPv4 address") | |
| parser.add_argument("port", type=int, help="destination UDP port") | |
| parser.add_argument("gso_size", type=int, help="UDP GSO segment payload size") | |
| parser.add_argument("payload_len", type=int, help="total UDP payload length") | |
| args = parser.parse_args() | |
| if args.gso_size <= 0 or args.gso_size > 0xFFFF: | |
| parser.error("gso_size must fit in an unsigned 16-bit integer") | |
| if args.payload_len <= args.gso_size: | |
| parser.error("payload_len must be larger than gso_size") | |
| if args.payload_len > args.gso_size * UDP_MAX_SEGMENTS: | |
| parser.error("payload_len exceeds UDP_MAX_SEGMENTS") | |
| SOL_UDP = getattr(socket, "SOL_UDP", socket.IPPROTO_UDP) | |
| UDP_SEGMENT = getattr(socket, "UDP_SEGMENT", 103) | |
| sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) | |
| sock.bind((args.src, 0)) | |
| payload = b"b" * args.payload_len | |
| cmsg = [(SOL_UDP, UDP_SEGMENT, struct.pack("=H", args.gso_size))] | |
| sent = sock.sendmsg([payload], cmsg, 0, (args.dst, args.port)) | |
| sys.exit(sent != len(payload)) |