frag4.py

#
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2025 Rubicon Communications, LLC (Netgate)
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

import pytest
from utils import DelayedSend
from atf_python.sys.net.tools import ToolsHelper
from atf_python.sys.net.vnet import VnetTestTemplate

class TestFrag4_NoReassemble(VnetTestTemplate):
    REQUIRED_MODULES = [ "pf" ]
    TOPOLOGY = {
        "vnet1": {"ifaces": ["if1"]},
        "vnet2": {"ifaces": ["if1", "if2"]},
        "vnet3": {"ifaces": ["if2"]},
        "if1": {"prefixes4": [("192.0.2.1/24", "192.0.2.2/24")]},
        "if2": {"prefixes4": [("198.51.100.1/24", "198.51.100.2/24")]},
    }

    def vnet2_handler(self, vnet):
        outifname = vnet.iface_alias_map["if2"].name

        ToolsHelper.print_output("/sbin/pfctl -e")
        ToolsHelper.pf_rules([
            "set reassemble no",
            "nat on %s from 192.0.2.0/24 to any -> (%s)" % (outifname, outifname),
            "pass out"
        ])

        ToolsHelper.print_output("/sbin/sysctl net.inet.ip.forwarding=1")

    def vnet3_handler(self, vnet):
        # We deliberately don't set the default gateway here, so if we get a
        # reply from this we know we did NAT in vnet2
        pass

    @pytest.mark.require_user("root")
    @pytest.mark.require_progs(["scapy"])
    def test_udp_frag(self):
        ToolsHelper.print_output("/sbin/route add default 192.0.2.2")
        ToolsHelper.print_output("/sbin/ping -c 3 198.51.100.2")

        # Import in the correct vnet, so at to not confuse Scapy
        import scapy.all as sp

        pkt = sp.IP(dst="198.51.100.2", frag=123) \
            / sp.UDP(dport=12345, sport=54321)
        reply = sp.sr1(pkt, timeout=3)
        # We don't expect a reply
        assert not reply