nat: 1:1 policy NAT

A NAT sub-plugin doing statically configured match/rewrite on IP4 input or output.
It's stateless (no connection tracking).
Currently it supports rewriting of SA, DA and TCP/UDP ports.
It should be simple to add new rewrites if required.

API:
pnat_binding_add, pnat_binding_del, pnat_bindings_get, pnat_interfaces_get

CLI:
set pnat translation interface <name> match <5-tuple> rewrite <5-tuple> {in|out} [del]
show pnat translations
show pnat interfaces

Trying a new C based unit testing scheme. Where the graph node is tested
in isolation. See pnat/pnat_test.c.
Also added new cmake targets to generate coverage directly.
E.g.:
make test_pnat-ccov-report

File '/vpp/sdnat/src/plugins/nat/pnat/pnat.c':
Name                               Regions    Miss   Cover     Lines    Miss   Cover
------------------------------------------------------------------------------------
pnat_interface_by_sw_if_index           39       8  79.49%        13       0 100.00%
pnat_instructions_from_mask              9       0 100.00%        13       0 100.00%
pnat_binding_add                        64       8  87.50%        31       2  93.55%
pnat_flow_lookup                         4       4   0.00%        10      10   0.00%
pnat_binding_attach                    104      75  27.88%        33       6  81.82%
pnat_binding_detach                     30       5  83.33%        23       2  91.30%
pnat_binding_del                        97      33  65.98%        17       3  82.35%
pnat.c:pnat_calc_key_from_5tuple         9       1  88.89%        14       1  92.86%
pnat.c:pnat_interface_check_mask        10       2  80.00%        11       2  81.82%
pnat.c:pnat_enable                       5       0 100.00%        11       0 100.00%
pnat.c:pnat_enable_interface           107      26  75.70%        60      15  75.00%
pnat.c:pnat_disable_interface           91      30  67.03%        32       7  78.12%
pnat.c:pnat_disable                      7       2  71.43%        13       7  46.15%
------------------------------------------------------------------------------------
TOTAL                                  576     194  66.32%       281      55  80.43%

File '/vpp/sdnat/src/plugins/nat/pnat/pnat_node.h':
Name                               Regions    Miss   Cover     Lines    Miss   Cover
------------------------------------------------------------------------------------
pnat_test.c:pnat_node_inline            67      11  83.58%       115       1  99.13%
pnat_test.c:pnat_calc_key                9       2  77.78%        14       2  85.71%
pnat_test.c:pnat_rewrite_ip4            55      11  80.00%        60      12  80.00%
pnat_test.c:format_pnat_trace            1       1   0.00%        12      12   0.00%
pnat_node.c:pnat_node_inline            63      63   0.00%       115     115   0.00%
pnat_node.c:pnat_calc_key                9       9   0.00%        14      14   0.00%
pnat_node.c:pnat_rewrite_ip4            55      55   0.00%        60      60   0.00%
pnat_node.c:format_pnat_trace            5       5   0.00%        12      12   0.00%
------------------------------------------------------------------------------------
TOTAL                                  264     157  40.53%       402     228  43.28%

Type: feature
Change-Id: I9c897f833603054a8303e7369ebff6512517c9e0
Signed-off-by: Ole Troan <ot@cisco.com>

1 files changed, 155 insertions, 0 deletions

diff --git a/src/plugins/nat/pnat/pnat.api b/src/plugins/nat/pnat/pnat.api
new file mode 100644
index 00000000000..c18c89445e9
--- /dev/null
+++ b/src/plugins/nat/pnat/pnat.api
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+option version = "0.0.1";
+
+import "vnet/interface_types.api";
+import "vnet/ip/ip_types.api";
+
+enum pnat_mask
+{
+    PNAT_SA = 0x1,
+    PNAT_DA = 0x2,
+    PNAT_SPORT = 0x4,
+    PNAT_DPORT = 0x8,
+};
+
+enum pnat_attachment_point
+{
+    PNAT_IP4_INPUT,
+    PNAT_IP4_OUTPUT,
+    PNAT_ATTACHMENT_POINT_MAX,
+};
+
+typedef pnat_5tuple
+{
+    vl_api_ip4_address_t src;
+    vl_api_ip4_address_t dst;
+    vl_api_ip_proto_t proto;
+    u16 sport;
+    u16 dport;
+    vl_api_pnat_mask_t mask;
+};
+
+autoendian define pnat_binding_add
+{
+    u32 client_index;
+    u32 context;
+    vl_api_pnat_5tuple_t match;
+    vl_api_pnat_5tuple_t rewrite;
+};
+
+autoendian define pnat_binding_add_reply
+{
+    u32 context;
+    i32 retval;
+    u32 binding_index;
+};
+
+autoendian autoreply define pnat_binding_del
+{
+    u32 client_index;
+    u32 context;
+    u32 binding_index;
+};
+
+autoendian autoreply define pnat_binding_attach
+{
+  u32 client_index;
+  u32 context;
+  vl_api_interface_index_t sw_if_index;
+  vl_api_pnat_attachment_point_t attachment;
+  u32 binding_index;
+};
+
+autoendian autoreply define pnat_binding_detach
+{
+  u32 client_index;
+  u32 context;
+  vl_api_interface_index_t sw_if_index;
+  vl_api_pnat_attachment_point_t attachment;
+  u32 binding_index;
+};
+
+service {
+  rpc pnat_bindings_get returns pnat_bindings_get_reply
+    stream pnat_bindings_details;
+  rpc pnat_interfaces_get returns pnat_interfaces_get_reply
+    stream pnat_interfaces_details;
+};
+
+define pnat_bindings_get
+{
+  u32 client_index;
+  u32 context;
+  u32 cursor;
+};
+
+define pnat_bindings_get_reply
+{
+  u32 context;
+  i32 retval;
+  u32 cursor;
+};
+
+define pnat_bindings_details
+{
+  u32 context;
+  vl_api_pnat_5tuple_t match;
+  vl_api_pnat_5tuple_t rewrite;
+};
+
+define pnat_interfaces_get
+{
+  u32 client_index;
+  u32 context;
+  u32 cursor;
+};
+
+define pnat_interfaces_get_reply
+{
+  u32 context;
+  i32 retval;
+  u32 cursor;
+};
+
+define pnat_interfaces_details
+{
+  u32 context;
+  vl_api_interface_index_t sw_if_index;
+  bool enabled[2]; /* PNAT_ATTACHMENT_POINT_MAX */
+  vl_api_pnat_mask_t lookup_mask[2]; /* PNAT_ATTACHMENT_POINT_MAX */
+};
+
+counters pnat {
+  none {
+    severity info;
+    type counter64;
+    units "packets";
+    description "successfully rewritten";
+  };
+
+  rewrite {
+    severity error;
+    type counter64;
+    units "packets";
+    description "rewrite failed";
+  };
+};
+
+paths {
+  "/err/pnat-input" "pnat";
+  "/err/pnat-output" "pnat";
+};