git: 32f793e22976 - main - pf tests: test handling of ICMP echo requests with the same ID

The branch main has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=32f793e2297619e1cb835c0938396ab6f6d0a6b3

commit 32f793e2297619e1cb835c0938396ab6f6d0a6b3
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2025-06-27 08:18:18 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2025-06-27 11:12:50 +0000

    pf tests: test handling of ICMP echo requests with the same ID
    
    We previously broke this, so add a test to prevent regressions.
    
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
---
 tests/sys/netpfil/pf/icmp.py | 77 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/tests/sys/netpfil/pf/icmp.py b/tests/sys/netpfil/pf/icmp.py
index 232c56a23dbf..83096886691e 100644
--- a/tests/sys/netpfil/pf/icmp.py
+++ b/tests/sys/netpfil/pf/icmp.py
@@ -175,3 +175,80 @@ class TestICMP(VnetTestTemplate):
         self.check_icmp_echo(sp, 128)
         self.check_icmp_echo(sp, 1464)
         self.check_icmp_echo(sp, 1468)
+
+class TestICMP_NAT(VnetTestTemplate):
+    REQUIRED_MODULES = [ "pf" ]
+    TOPOLOGY = {
+        "vnet1": {"ifaces": ["if1"]},
+        "vnet2": {"ifaces": ["if1", "if2"]},
+        "vnet3": {"ifaces": ["if2"]},
+        "if1": {"prefixes4": [("192.0.2.2/24", "192.0.2.1/24")]},
+        "if2": {"prefixes4": [("198.51.100.1/24", "198.51.100.2/24")]},
+    }
+
+    def vnet2_handler(self, vnet):
+        ifname = vnet.iface_alias_map["if1"].name
+        if2name = vnet.iface_alias_map["if2"].name
+
+        ToolsHelper.print_output("/sbin/pfctl -e")
+        ToolsHelper.pf_rules([
+            "set reassemble yes",
+            "set state-policy if-bound",
+            "nat on %s inet from 192.0.2.0/24 to any -> (%s)" % (if2name, if2name),
+            "block",
+            "pass inet proto icmp icmp-type echoreq",
+            ])
+
+        ToolsHelper.print_output("/sbin/sysctl net.inet.ip.forwarding=1")
+        ToolsHelper.print_output("/sbin/pfctl -x loud")
+
+    def vnet3_handler(self, vnet):
+        ifname = vnet.iface_alias_map["if2"].name
+        ToolsHelper.print_output("/sbin/ifconfig %s inet alias 198.51.100.3/24" % ifname)
+
+    @pytest.mark.require_user("root")
+    @pytest.mark.require_progs(["scapy"])
+    def test_id_conflict(self):
+        """
+            Test ICMP echo requests with the same ID from different clients.
+            Windows does this, and it can confuse pf.
+        """
+        ifname = self.vnet.iface_alias_map["if1"].name
+        ToolsHelper.print_output("/sbin/route add default 192.0.2.1")
+        ToolsHelper.print_output("/sbin/ifconfig %s inet alias 192.0.2.3/24" % ifname)
+
+        ToolsHelper.print_output("/sbin/ping -c 1 192.0.2.1")
+        ToolsHelper.print_output("/sbin/ping -c 1 198.51.100.1")
+        ToolsHelper.print_output("/sbin/ping -c 1 198.51.100.2")
+        ToolsHelper.print_output("/sbin/ping -c 1 198.51.100.3")
+
+        # Import in the correct vnet, so at to not confuse Scapy
+        import scapy.all as sp
+
+        # Address one
+        packet = sp.IP(src="192.0.2.2", dst="198.51.100.2", flags="DF") \
+            / sp.ICMP(type='echo-request', id=42) \
+            / sp.raw(bytes.fromhex('f0') * 16)
+
+        p = sp.sr1(packet, timeout=3)
+        p.show()
+        ip = p.getlayer(sp.IP)
+        icmp = p.getlayer(sp.ICMP)
+        assert ip
+        assert icmp
+        assert ip.dst == "192.0.2.2"
+        assert icmp.id == 42
+
+        # Address one
+        packet = sp.IP(src="192.0.2.3", dst="198.51.100.2", flags="DF") \
+            / sp.ICMP(type='echo-request', id=42) \
+            / sp.raw(bytes.fromhex('f0') * 16)
+
+        p = sp.sr1(packet, timeout=3)
+        p.show()
+        ip = p.getlayer(sp.IP)
+        icmp = p.getlayer(sp.ICMP)
+        assert ip
+        assert icmp
+        assert ip.dst == "192.0.2.3"
+        assert icmp.id == 42