1*54704b32SXingquan Liu#!/usr/bin/env python3 2*54704b32SXingquan Liu# SPDX-License-Identifier: GPL-2.0 3*54704b32SXingquan Liu 4*54704b32SXingquan Liu""" 5*54704b32SXingquan Liutdc_gso.py - send a UDP GSO datagram 6*54704b32SXingquan Liu 7*54704b32SXingquan LiuCopyright (C) 2026 Xingquan Liu <b1n@b1n.io> 8*54704b32SXingquan Liu""" 9*54704b32SXingquan Liu 10*54704b32SXingquan Liuimport argparse 11*54704b32SXingquan Liuimport socket 12*54704b32SXingquan Liuimport struct 13*54704b32SXingquan Liuimport sys 14*54704b32SXingquan Liu 15*54704b32SXingquan LiuUDP_MAX_SEGMENTS = 1 << 7 16*54704b32SXingquan Liu 17*54704b32SXingquan Liu 18*54704b32SXingquan Liuparser = argparse.ArgumentParser(description="UDP GSO datagram sender") 19*54704b32SXingquan Liuparser.add_argument("src", help="source IPv4 address") 20*54704b32SXingquan Liuparser.add_argument("dst", help="destination IPv4 address") 21*54704b32SXingquan Liuparser.add_argument("port", type=int, help="destination UDP port") 22*54704b32SXingquan Liuparser.add_argument("gso_size", type=int, help="UDP GSO segment payload size") 23*54704b32SXingquan Liuparser.add_argument("payload_len", type=int, help="total UDP payload length") 24*54704b32SXingquan Liuargs = parser.parse_args() 25*54704b32SXingquan Liu 26*54704b32SXingquan Liuif args.gso_size <= 0 or args.gso_size > 0xFFFF: 27*54704b32SXingquan Liu parser.error("gso_size must fit in an unsigned 16-bit integer") 28*54704b32SXingquan Liuif args.payload_len <= args.gso_size: 29*54704b32SXingquan Liu parser.error("payload_len must be larger than gso_size") 30*54704b32SXingquan Liuif args.payload_len > args.gso_size * UDP_MAX_SEGMENTS: 31*54704b32SXingquan Liu parser.error("payload_len exceeds UDP_MAX_SEGMENTS") 32*54704b32SXingquan Liu 33*54704b32SXingquan LiuSOL_UDP = getattr(socket, "SOL_UDP", socket.IPPROTO_UDP) 34*54704b32SXingquan LiuUDP_SEGMENT = getattr(socket, "UDP_SEGMENT", 103) 35*54704b32SXingquan Liu 36*54704b32SXingquan Liusock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 37*54704b32SXingquan Liusock.bind((args.src, 0)) 38*54704b32SXingquan Liu 39*54704b32SXingquan Liupayload = b"b" * args.payload_len 40*54704b32SXingquan Liucmsg = [(SOL_UDP, UDP_SEGMENT, struct.pack("=H", args.gso_size))] 41*54704b32SXingquan Liu 42*54704b32SXingquan Liusent = sock.sendmsg([payload], cmsg, 0, (args.dst, args.port)) 43*54704b32SXingquan Liusys.exit(sent != len(payload)) 44