From 6fa74c60ea5930864750d64005b213647f12fe08 Mon Sep 17 00:00:00 2001 From: Matus Fabian Date: Mon, 5 Jun 2017 05:55:48 -0700 Subject: SNAT: fix ICMP hairpinning Change-Id: I9d63133bd1db72917571ade868040c4597c896a1 Signed-off-by: Matus Fabian --- src/plugins/snat/in2out.c | 68 ++++++++++++++++++- test/test_snat.py | 166 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 231 insertions(+), 3 deletions(-) diff --git a/src/plugins/snat/in2out.c b/src/plugins/snat/in2out.c index bc86a7a4..ddde702a 100644 --- a/src/plugins/snat/in2out.c +++ b/src/plugins/snat/in2out.c @@ -515,7 +515,7 @@ u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node, goto out; } - if (PREDICT_FALSE(icmp0->type != ICMP4_echo_request)) + if (PREDICT_FALSE(icmp_is_error_message (icmp0))) { b0->error = node->errors[SNAT_IN2OUT_ERROR_BAD_ICMP_TYPE]; next0 = SNAT_IN2OUT_NEXT_DROP; @@ -869,11 +869,77 @@ static inline u32 icmp_in2out_slow_path (snat_main_t *sm, u32 thread_index, snat_session_t ** p_s0) { + snat_session_key_t key0, sm0; + clib_bihash_kv_8_8_t kv0, value0; + snat_worker_key_t k0; + u32 new_dst_addr0 = 0, old_dst_addr0, si, ti = 0; + ip_csum_t sum0; + next0 = icmp_in2out(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0, thread_index, p_s0, 0); snat_session_t * s0 = *p_s0; if (PREDICT_TRUE(next0 != SNAT_IN2OUT_NEXT_DROP && s0)) { + /* Hairpinning */ + if (!icmp_is_error_message (icmp0)) + { + icmp_echo_header_t *echo0 = (icmp_echo_header_t *)(icmp0+1); + u16 icmp_id0 = echo0->identifier; + key0.addr = ip0->dst_address; + key0.port = icmp_id0; + key0.protocol = SNAT_PROTOCOL_ICMP; + key0.fib_index = sm->outside_fib_index; + kv0.key = key0.as_u64; + + /* Check if destination is in active sessions */ + if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0)) + { + /* or static mappings */ + if (!snat_static_mapping_match(sm, key0, &sm0, 1, 0)) + { + new_dst_addr0 = sm0.addr.as_u32; + vnet_buffer(b0)->sw_if_index[VLIB_TX] = sm0.fib_index; + } + } + else + { + si = value0.value; + if (sm->num_workers > 1) + { + k0.addr = ip0->dst_address; + k0.port = icmp_id0; + k0.fib_index = sm->outside_fib_index; + kv0.key = k0.as_u64; + if (clib_bihash_search_8_8 (&sm->worker_by_out, &kv0, &value0)) + ASSERT(0); + else + ti = value0.value; + } + else + ti = sm->num_workers; + + s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si); + new_dst_addr0 = s0->in2out.addr.as_u32; + vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index; + echo0->identifier = s0->in2out.port; + sum0 = icmp0->checksum; + sum0 = ip_csum_update (sum0, icmp_id0, s0->in2out.port, + icmp_echo_header_t, identifier); + icmp0->checksum = ip_csum_fold (sum0); + } + + /* Destination is behind the same NAT, use internal address and port */ + if (new_dst_addr0) + { + old_dst_addr0 = ip0->dst_address.as_u32; + ip0->dst_address.as_u32 = new_dst_addr0; + sum0 = ip0->checksum; + sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0, + ip4_header_t, dst_address); + ip0->checksum = ip_csum_fold (sum0); + } + } + /* Accounting */ s0->last_heard = now; s0->total_pkts++; diff --git a/test/test_snat.py b/test/test_snat.py index 8d384384..0eceaab2 100644 --- a/test/test_snat.py +++ b/test/test_snat.py @@ -324,7 +324,7 @@ class TestSNAT(MethodHolder): i.config_ip4() i.resolve_arp() - cls.pg0.generate_remote_hosts(2) + cls.pg0.generate_remote_hosts(3) cls.pg0.configure_ipv4_neighbors() cls.overlapping_interfaces = list(list(cls.pg_interfaces[4:7])) @@ -1016,7 +1016,7 @@ class TestSNAT(MethodHolder): self.icmp_id_in]) def test_hairpinning(self): - """ SNAT hairpinning """ + """ SNAT hairpinning - 1:1 NAT with port""" host = self.pg0.remote_hosts[0] server = self.pg0.remote_hosts[1] @@ -1075,6 +1075,168 @@ class TestSNAT(MethodHolder): self.logger.error(ppp("Unexpected or invalid packet:"), p) raise + def test_hairpinning2(self): + """ SNAT hairpinning - 1:1 NAT""" + + server1_nat_ip = "10.0.0.10" + server2_nat_ip = "10.0.0.11" + host = self.pg0.remote_hosts[0] + server1 = self.pg0.remote_hosts[1] + server2 = self.pg0.remote_hosts[2] + server_tcp_port = 22 + server_udp_port = 20 + + self.snat_add_address(self.snat_addr) + self.vapi.snat_interface_add_del_feature(self.pg0.sw_if_index) + self.vapi.snat_interface_add_del_feature(self.pg1.sw_if_index, + is_inside=0) + + # add static mapping for servers + self.snat_add_static_mapping(server1.ip4, server1_nat_ip) + self.snat_add_static_mapping(server2.ip4, server2_nat_ip) + + # host to server1 + pkts = [] + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=host.ip4, dst=server1_nat_ip) / + TCP(sport=self.tcp_port_in, dport=server_tcp_port)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=host.ip4, dst=server1_nat_ip) / + UDP(sport=self.udp_port_in, dport=server_udp_port)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=host.ip4, dst=server1_nat_ip) / + ICMP(id=self.icmp_id_in, type='echo-request')) + pkts.append(p) + self.pg0.add_stream(pkts) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg0.get_capture(len(pkts)) + for packet in capture: + try: + self.assertEqual(packet[IP].src, self.snat_addr) + self.assertEqual(packet[IP].dst, server1.ip4) + if packet.haslayer(TCP): + self.assertNotEqual(packet[TCP].sport, self.tcp_port_in) + self.assertEqual(packet[TCP].dport, server_tcp_port) + self.tcp_port_out = packet[TCP].sport + elif packet.haslayer(UDP): + self.assertNotEqual(packet[UDP].sport, self.udp_port_in) + self.assertEqual(packet[UDP].dport, server_udp_port) + self.udp_port_out = packet[UDP].sport + else: + self.assertNotEqual(packet[ICMP].id, self.icmp_id_in) + self.icmp_id_out = packet[ICMP].id + except: + self.logger.error(ppp("Unexpected or invalid packet:", packet)) + raise + + # server1 to host + pkts = [] + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=self.snat_addr) / + TCP(sport=server_tcp_port, dport=self.tcp_port_out)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=self.snat_addr) / + UDP(sport=server_udp_port, dport=self.udp_port_out)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=self.snat_addr) / + ICMP(id=self.icmp_id_out, type='echo-reply')) + pkts.append(p) + self.pg0.add_stream(pkts) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg0.get_capture(len(pkts)) + for packet in capture: + try: + self.assertEqual(packet[IP].src, server1_nat_ip) + self.assertEqual(packet[IP].dst, host.ip4) + if packet.haslayer(TCP): + self.assertEqual(packet[TCP].dport, self.tcp_port_in) + self.assertEqual(packet[TCP].sport, server_tcp_port) + elif packet.haslayer(UDP): + self.assertEqual(packet[UDP].dport, self.udp_port_in) + self.assertEqual(packet[UDP].sport, server_udp_port) + else: + self.assertEqual(packet[ICMP].id, self.icmp_id_in) + except: + self.logger.error(ppp("Unexpected or invalid packet:", packet)) + raise + + # server2 to server1 + pkts = [] + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server2.ip4, dst=server1_nat_ip) / + TCP(sport=self.tcp_port_in, dport=server_tcp_port)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server2.ip4, dst=server1_nat_ip) / + UDP(sport=self.udp_port_in, dport=server_udp_port)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server2.ip4, dst=server1_nat_ip) / + ICMP(id=self.icmp_id_in, type='echo-request')) + pkts.append(p) + self.pg0.add_stream(pkts) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg0.get_capture(len(pkts)) + for packet in capture: + try: + self.assertEqual(packet[IP].src, server2_nat_ip) + self.assertEqual(packet[IP].dst, server1.ip4) + if packet.haslayer(TCP): + self.assertEqual(packet[TCP].sport, self.tcp_port_in) + self.assertEqual(packet[TCP].dport, server_tcp_port) + self.tcp_port_out = packet[TCP].sport + elif packet.haslayer(UDP): + self.assertEqual(packet[UDP].sport, self.udp_port_in) + self.assertEqual(packet[UDP].dport, server_udp_port) + self.udp_port_out = packet[UDP].sport + else: + self.assertEqual(packet[ICMP].id, self.icmp_id_in) + self.icmp_id_out = packet[ICMP].id + except: + self.logger.error(ppp("Unexpected or invalid packet:", packet)) + raise + + # server1 to server2 + pkts = [] + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=server2_nat_ip) / + TCP(sport=server_tcp_port, dport=self.tcp_port_out)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=server2_nat_ip) / + UDP(sport=server_udp_port, dport=self.udp_port_out)) + pkts.append(p) + p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) / + IP(src=server1.ip4, dst=server2_nat_ip) / + ICMP(id=self.icmp_id_out, type='echo-reply')) + pkts.append(p) + self.pg0.add_stream(pkts) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg0.get_capture(len(pkts)) + for packet in capture: + try: + self.assertEqual(packet[IP].src, server1_nat_ip) + self.assertEqual(packet[IP].dst, server2.ip4) + if packet.haslayer(TCP): + self.assertEqual(packet[TCP].dport, self.tcp_port_in) + self.assertEqual(packet[TCP].sport, server_tcp_port) + elif packet.haslayer(UDP): + self.assertEqual(packet[UDP].dport, self.udp_port_in) + self.assertEqual(packet[UDP].sport, server_udp_port) + else: + self.assertEqual(packet[ICMP].id, self.icmp_id_in) + except: + self.logger.error(ppp("Unexpected or invalid packet:", packet)) + raise + def test_max_translations_per_user(self): """ MAX translations per user - recycle the least recently used """ -- cgit 1.2.3-korg