From 6b97c43005f6458ce2e253f87af6f609eaebef60 Mon Sep 17 00:00:00 2001 From: Dmitry Valter Date: Fri, 9 Dec 2022 19:34:22 +0000 Subject: nat: fix accidental o2i deletion/reuse Nat session is allocated before the port allocation. During port allocation candidate address+port are set to o2i 6-tuple and tested against the flow hash. If insertion fails, the port is busy and rejected. When all N attempts are unsuccessful, "out-of-ports" error is recorded and the session is to be deleted. During session deletion o2i and i2o tuples are deleted from the flow hash. In case of "out-of-ports" i2o tuple is not valid, however o2i is and it refers to **some other** session that's known to be allocated. By backing match tuple up session should be invalidated well enough not to collide with any valid one. Type: fix Signed-off-by: Dmitry Valter Change-Id: Id30be6f26ecce7a5a63135fb971bb65ce318af82 --- test/test_nat44_ed.py | 75 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 73 insertions(+), 2 deletions(-) (limited to 'test') diff --git a/test/test_nat44_ed.py b/test/test_nat44_ed.py index 8a8c96870f4..7279b6a7d56 100644 --- a/test/test_nat44_ed.py +++ b/test/test_nat44_ed.py @@ -4,6 +4,7 @@ import unittest from io import BytesIO from random import randint, choice +import re import scapy.compat from framework import tag_fixme_ubuntu2204, is_distro_ubuntu2204 from framework import VppTestCase, VppTestRunner, VppLoInterface @@ -48,8 +49,9 @@ class TestNAT44ED(VppTestCase): if not self.vpp_dead: self.plugin_disable() - def plugin_enable(self): - self.vapi.nat44_ed_plugin_enable_disable(sessions=self.max_sessions, enable=1) + def plugin_enable(self, max_sessions=None): + max_sessions = max_sessions or self.max_sessions + self.vapi.nat44_ed_plugin_enable_disable(sessions=max_sessions, enable=1) def plugin_disable(self): self.vapi.nat44_ed_plugin_enable_disable(enable=0) @@ -616,6 +618,16 @@ class TestNAT44ED(VppTestCase): return pkts + def create_udp_stream(self, in_if, out_if, count, base_port=6303): + return [ + ( + Ether(dst=in_if.local_mac, src=in_if.remote_mac) + / IP(src=in_if.remote_ip4, dst=out_if.remote_ip4, ttl=64) + / UDP(sport=base_port + i, dport=20) + ) + for i in range(count) + ] + def create_stream_frag( self, src_if, dst, sport, dport, data, proto=IP_PROTOS.tcp, echo_reply=False ): @@ -4821,6 +4833,65 @@ class TestNAT44EDMW(TestNAT44ED): ) self.send_and_expect(self.pg0, p, self.pg1) + def test_dynamic_ports_exhausted(self): + """NAT44ED dynamic translation test: address ports exhaused""" + + sessions_per_batch = 128 + n_available_ports = 65536 - 1024 + n_sessions = n_available_ports + 2 * sessions_per_batch + + # set high enough session limit for ports to be exhausted + self.plugin_disable() + self.plugin_enable(max_sessions=n_sessions) + + self.nat_add_inside_interface(self.pg0) + self.nat_add_outside_interface(self.pg1) + + # set timeouts to high for sessions to reallistically expire + config = self.vapi.nat44_show_running_config() + old_timeouts = config.timeouts + self.vapi.nat_set_timeouts( + udp=21600, + tcp_established=old_timeouts.tcp_established, + tcp_transitory=old_timeouts.tcp_transitory, + icmp=old_timeouts.icmp, + ) + + # in2out after NAT addresses added + self.nat_add_address(self.nat_addr) + + for i in range(n_sessions // sessions_per_batch): + pkts = self.create_udp_stream( + self.pg0, + self.pg1, + sessions_per_batch, + base_port=i * sessions_per_batch + 100, + ) + + self.pg0.add_stream(pkts) + self.pg_start() + + err = self.statistics.get_err_counter( + "/err/nat44-ed-in2out-slowpath/out of ports" + ) + if err > sessions_per_batch: + break + + # Check for ports to be used no more than once + ports = set() + sessions = self.vapi.cli("show nat44 sessions") + rx = re.compile( + f" *o2i flow: match: saddr {self.pg1.remote_ip4} sport [0-9]+ daddr {self.nat_addr} dport ([0-9]+) proto UDP.*" + ) + for line in sessions.splitlines(): + m = rx.match(line) + if m: + port = int(m.groups()[0]) + self.assertNotIn(port, ports) + ports.add(port) + + self.assertGreaterEqual(err, sessions_per_batch) + if __name__ == "__main__": unittest.main(testRunner=VppTestRunner) -- cgit 1.2.3-korg