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, 504 insertions, 0 deletions

diff --git a/src/plugins/nat/pnat/pnat_test.c b/src/plugins/nat/pnat/pnat_test.c
new file mode 100644
index 00000000000..762b4bdb3f0
--- /dev/null
+++ b/src/plugins/nat/pnat/pnat_test.c
@@ -0,0 +1,504 @@
+/*
+ * 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.
+ */
+
+#include <stdbool.h>
+#include <assert.h>
+#include <vlib/vlib.h>
+#include <vnet/feature/feature.h>
+#include <vppinfra/clib_error.h>
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/udp/udp.h>
+#include <vppinfra/bihash_16_8.h>
+#include <vppinfra/bihash_template.c>
+#include <vnet/fib/ip4_fib.h>
+#include "pnat.h"
+#include <pnat/pnat.api_enum.h> /* For error counters */
+#include <arpa/inet.h>
+#include "pnat_test_stubs.h"
+
+/*
+** Buffer management in test setup
+** Allocate buffers return vector of buffer indicies.
+**
+** Setup frame with buffers when calling function.
+** Global vector of all buffers with their indicies?
+** Convert buffer index to pointer?
+*/
+struct buffers {
+    u8 data[2048];
+};
+struct buffers buffers[256];
+struct buffers expected[256];
+u32 *buffers_vector = 0;
+
+static u32 *buffer_init(u32 *vector, int count) {
+    int i;
+    for (i = 0; i < count; i++) {
+        vec_add1(vector, i);
+    }
+    return vector;
+}
+#define PNAT_TEST_DEBUG 0
+
+u32 *results_bi = 0; /* global vector of result buffers */
+u16 *results_next = 0;
+vlib_node_runtime_t *node;
+
+#define log_info(M, ...)                                                       \
+    fprintf(stderr, "\033[32;1m[OK] " M "\033[0m\n", ##__VA_ARGS__)
+#define log_error(M, ...)                                                      \
+    fprintf(stderr, "\033[31;1m[ERROR] (%s:%d:) " M "\033[0m\n", __FILE__,     \
+            __LINE__, ##__VA_ARGS__)
+#define test_assert(A, M, ...)                                                 \
+    if (!(A)) {                                                                \
+        log_error(M, ##__VA_ARGS__);                                           \
+        assert(A);                                                             \
+    } else {                                                                   \
+        log_info(M, ##__VA_ARGS__);                                            \
+    }
+
+/*
+ * Always return the frame of generated packets
+ */
+#define vlib_frame_vector_args test_vlib_frame_vector_args
+void *test_vlib_frame_vector_args(vlib_frame_t *f) { return buffers_vector; }
+
+/* Synthetic value for vnet_feature_next  */
+#define NEXT_PASSTHROUGH 4242
+
+#define vnet_feature_next_u16 test_vnet_feature_next_u16
+void vnet_feature_next_u16(u16 *next0, vlib_buffer_t *b0) {
+    *next0 = NEXT_PASSTHROUGH;
+}
+
+/* Gather output packets */
+#define vlib_buffer_enqueue_to_next test_vlib_buffer_enqueue_to_next
+void test_vlib_buffer_enqueue_to_next(vlib_main_t *vm,
+                                      vlib_node_runtime_t *node, u32 *buffers,
+                                      u16 *nexts, uword count) {
+    vec_add(results_next, nexts, count);
+    vec_add(results_bi, buffers, count);
+}
+
+pnat_trace_t trace = {0};
+#define vlib_add_trace test_vlib_add_trace
+void *test_vlib_add_trace(vlib_main_t *vm, vlib_node_runtime_t *r,
+                          vlib_buffer_t *b, u32 n_data_bytes) {
+    return &trace;
+}
+
+#define vlib_get_buffers test_vlib_get_buffers
+void test_vlib_get_buffers(vlib_main_t *vm, u32 *bi, vlib_buffer_t **b,
+                           int count) {
+    int i;
+    for (i = 0; i < count; i++) {
+        b[i] = (vlib_buffer_t *)&buffers[bi[i]];
+    }
+}
+
+vlib_buffer_t *test_vlib_get_buffer(u32 bi) {
+    return (vlib_buffer_t *)&buffers[bi];
+}
+
+/* Must be included here to allow the above functions to override */
+#include "pnat_node.h"
+
+/*** TESTS ***/
+
+typedef struct {
+    char *src;
+    char *dst;
+    u8 proto;
+    u16 sport;
+    u16 dport;
+} test_5tuple_t;
+
+typedef struct {
+    char *name;
+    test_5tuple_t send;
+    test_5tuple_t expect;
+    u32 expect_next_index;
+} test_t;
+
+test_t tests[] = {
+    {
+        .name = "da rewritten",
+        .send = {"1.1.1.1", "2.2.2.2", 17, 80, 6871},
+        .expect = {"1.1.1.1", "1.2.3.4", 17, 80, 6871},
+        .expect_next_index = NEXT_PASSTHROUGH,
+    },
+    {
+        .name = "unchanged",
+        .send = {"1.1.1.1", "2.2.2.2", 17, 80, 8080},
+        .expect = {"1.1.1.1", "2.2.2.2", 17, 80, 8080},
+        .expect_next_index = NEXT_PASSTHROUGH,
+    },
+    {
+        .name = "tcp da",
+        .send = {"1.1.1.1", "2.2.2.2", 6, 80, 6871},
+        .expect = {"1.1.1.1", "1.2.3.4", 6, 80, 6871},
+        .expect_next_index = NEXT_PASSTHROUGH,
+    },
+    {
+        .name = "tcp da ports",
+        .send = {"1.1.1.1", "2.2.2.2", 6, 80, 6872},
+        .expect = {"1.1.1.1", "1.2.3.4", 6, 53, 8000},
+        .expect_next_index = NEXT_PASSTHROUGH,
+    },
+};
+
+/* Rules */
+typedef struct {
+    test_5tuple_t match;
+    test_5tuple_t rewrite;
+    bool in;
+    u32 index;
+} rule_t;
+
+rule_t rules[] = {
+    {
+        .match = {.dst = "2.2.2.2", .proto = 17, .dport = 6871},
+        .rewrite = {.dst = "1.2.3.4"},
+        .in = true,
+    },
+    {
+        .match = {.dst = "2.2.2.2", .proto = 6, .dport = 6871},
+        .rewrite = {.dst = "1.2.3.4"},
+        .in = true,
+    },
+    {
+        .match = {.dst = "2.2.2.2", .proto = 6, .dport = 6872},
+        .rewrite = {.dst = "1.2.3.4", .sport = 53, .dport = 8000},
+        .in = true,
+    },
+    {
+        .match = {.dst = "2.2.2.2", .proto = 6, .dport = 6873},
+        .rewrite = {.dst = "1.2.3.4", .sport = 53, .dport = 8000},
+        .in = true,
+    },
+};
+
+static int fill_packets(vlib_main_t *vm, vlib_buffer_t *b,
+                        test_5tuple_t *test) {
+    b->flags |= VLIB_BUFFER_IS_TRACED;
+
+    ip4_header_t *ip = (ip4_header_t *)vlib_buffer_get_current(b);
+    memset(ip, 0, sizeof(*ip));
+    ip->ip_version_and_header_length = 0x45;
+    ip->ttl = 64;
+    inet_pton(AF_INET, test->src, &ip->src_address.as_u32);
+    inet_pton(AF_INET, test->dst, &ip->dst_address.as_u32);
+    ip->protocol = test->proto;
+
+    if (test->proto == IP_PROTOCOL_UDP) {
+        udp_header_t *udp = ip4_next_header(ip);
+        memset(udp, 0, sizeof(*udp));
+        udp->dst_port = htons(test->dport);
+        udp->src_port = htons(test->sport);
+        udp->length = htons(8);
+        vnet_buffer(b)->ip.reass.l4_src_port = udp->src_port;
+        vnet_buffer(b)->ip.reass.l4_dst_port = udp->dst_port;
+        b->current_length = 28;
+        ip->length = htons(b->current_length);
+        ip->checksum = ip4_header_checksum(ip);
+        udp->checksum = ip4_tcp_udp_compute_checksum(vm, b, ip);
+    } else if (test->proto == IP_PROTOCOL_TCP) {
+        tcp_header_t *tcp = ip4_next_header(ip);
+        memset(tcp, 0, sizeof(*tcp));
+        tcp->dst_port = htons(test->dport);
+        tcp->src_port = htons(test->sport);
+        vnet_buffer(b)->ip.reass.l4_src_port = tcp->src_port;
+        vnet_buffer(b)->ip.reass.l4_dst_port = tcp->dst_port;
+        b->current_length = sizeof(ip4_header_t) + sizeof(tcp_header_t);
+        ip->length = htons(b->current_length);
+        ip->checksum = ip4_header_checksum(ip);
+        tcp->checksum = ip4_tcp_udp_compute_checksum(vm, b, ip);
+    } else {
+        b->current_length = sizeof(ip4_header_t);
+        ip->length = htons(b->current_length);
+        ip->checksum = ip4_header_checksum(ip);
+        vnet_buffer(b)->ip.reass.l4_src_port = 0;
+        vnet_buffer(b)->ip.reass.l4_dst_port = 0;
+    }
+
+    return 0;
+}
+
+static void ruleto5tuple(test_5tuple_t *r, pnat_5tuple_t *t) {
+    if (r->src) {
+        inet_pton(AF_INET, r->src, &t->src);
+        t->mask |= PNAT_SA;
+    }
+    if (r->dst) {
+        inet_pton(AF_INET, r->dst, &t->dst);
+        t->mask |= PNAT_DA;
+    }
+    if (r->dport) {
+        t->dport = r->dport;
+        t->mask |= PNAT_DPORT;
+    }
+    if (r->sport) {
+        t->sport = r->sport;
+        t->mask |= PNAT_SPORT;
+    }
+    t->proto = r->proto;
+}
+
+static void add_translation(rule_t *r) {
+    pnat_5tuple_t match = {0};
+    pnat_5tuple_t rewrite = {0};
+
+    ruleto5tuple(&r->match, &match);
+    ruleto5tuple(&r->rewrite, &rewrite);
+
+    int rv = pnat_binding_add(&match, &rewrite, &r->index);
+    assert(rv == 0);
+
+    rv = pnat_binding_attach(0, PNAT_IP4_INPUT, r->index);
+    assert(rv == 0);
+}
+
+static void del_translation(rule_t *r) {
+    int rv = pnat_binding_detach(0, PNAT_IP4_INPUT, r->index);
+    assert(rv == 0);
+
+    rv = pnat_binding_del(r->index);
+    assert(rv == 0);
+}
+
+static void validate_packet(vlib_main_t *vm, char *name, u32 bi,
+                            vlib_buffer_t *expected_b) {
+    vlib_buffer_t *b = test_vlib_get_buffer(bi);
+    assert(b);
+
+    ip4_header_t *ip = (ip4_header_t *)vlib_buffer_get_current(b);
+    ip4_header_t *expected_ip =
+        (ip4_header_t *)vlib_buffer_get_current(expected_b);
+
+#if PNAT_TEST_DEBUG
+    clib_warning("Received packet: %U", format_ip4_header, ip, 20);
+    clib_warning("Expected packet: %U", format_ip4_header, expected_ip, 20);
+    tcp_header_t *tcp = ip4_next_header(ip);
+    clib_warning("IP: %U TCP: %U", format_ip4_header, ip, sizeof(*ip),
+                 format_tcp_header, tcp, sizeof(*tcp));
+    tcp = ip4_next_header(expected_ip);
+    clib_warning("IP: %U TCP: %U", format_ip4_header, expected_ip, sizeof(*ip),
+                 format_tcp_header, tcp, sizeof(*tcp));
+#endif
+
+    u32 flags = ip4_tcp_udp_validate_checksum(vm, b);
+    assert((flags & VNET_BUFFER_F_L4_CHECKSUM_CORRECT) != 0);
+    flags = ip4_tcp_udp_validate_checksum(vm, expected_b);
+    assert((flags & VNET_BUFFER_F_L4_CHECKSUM_CORRECT) != 0);
+    assert(b->current_length == expected_b->current_length);
+
+    test_assert(memcmp(ip, expected_ip, b->current_length) == 0, "%s", name);
+}
+
+extern vlib_node_registration_t pnat_input_node;
+
+static void test_table(test_t *t, int no_tests) {
+    // walk through table of tests
+    int i;
+    vlib_main_t *vm = &vlib_global_main;
+
+    /* Generate packet data */
+    for (i = 0; i < no_tests; i++) {
+        // create input buffer(s)
+        fill_packets(vm, (vlib_buffer_t *)&buffers[i], &t[i].send);
+        fill_packets(vm, (vlib_buffer_t *)&expected[i], &t[i].expect);
+    }
+
+    /* send packets through graph node */
+    vlib_frame_t frame = {.n_vectors = no_tests};
+    node->flags |= VLIB_NODE_FLAG_TRACE;
+
+    pnat_node_inline(vm, node, &frame, PNAT_IP4_INPUT, VLIB_RX);
+
+    /* verify tests */
+    for (i = 0; i < no_tests; i++) {
+        assert(t[i].expect_next_index == results_next[i]);
+        validate_packet(vm, t[i].name, results_bi[i],
+                        (vlib_buffer_t *)&expected[i]);
+    }
+    vec_free(results_next);
+    vec_free(results_bi);
+}
+
+static void test_performance(void) {
+    pnat_main_t *pm = &pnat_main;
+    int i;
+    vlib_main_t *vm = &vlib_global_main;
+
+    for (i = 0; i < sizeof(rules) / sizeof(rules[0]); i++) {
+        add_translation(&rules[i]);
+    }
+    assert(pool_elts(pm->translations) == sizeof(rules) / sizeof(rules[0]));
+
+    int no_tests = sizeof(tests) / sizeof(tests[0]);
+    /* Generate packet data */
+    for (i = 0; i < VLIB_FRAME_SIZE; i++) {
+        // create input buffer(s)
+        fill_packets(vm, (vlib_buffer_t *)&buffers[i],
+                     &tests[i % no_tests].send);
+        // fill_packets(vm, (vlib_buffer_t *)&expected[i], &tests[i %
+        // no_tests].expect);
+    }
+
+    /* send packets through graph node */
+    vlib_frame_t frame = {.n_vectors = VLIB_FRAME_SIZE};
+    node->flags &= ~VLIB_NODE_FLAG_TRACE;
+
+    int j;
+    for (j = 0; j < 10000; j++) {
+        pnat_node_inline(vm, node, &frame, PNAT_IP4_INPUT, VLIB_RX);
+
+#if 0
+    for (i = 0; i < VLIB_FRAME_SIZE; i++) {
+        assert(tests[i % no_tests].expect_next_index == results_next[i]);
+        validate_packet(vm, tests[i % no_tests].name, results_bi[i], (vlib_buffer_t *)&expected[i]);
+    }
+#endif
+        vec_free(results_next);
+        vec_free(results_bi);
+    }
+
+    for (i = 0; i < sizeof(rules) / sizeof(rules[0]); i++) {
+        del_translation(&rules[i]);
+    }
+    assert(pool_elts(pm->translations) == 0);
+    assert(pool_elts(pm->interfaces) == 0);
+}
+
+static void test_packets(void) {
+    pnat_main_t *pm = &pnat_main;
+    int i;
+    for (i = 0; i < sizeof(rules) / sizeof(rules[0]); i++) {
+        add_translation(&rules[i]);
+    }
+    assert(pool_elts(pm->translations) == sizeof(rules) / sizeof(rules[0]));
+
+    test_table(tests, sizeof(tests) / sizeof(tests[0]));
+
+    for (i = 0; i < sizeof(rules) / sizeof(rules[0]); i++) {
+        del_translation(&rules[i]);
+    }
+    assert(pool_elts(pm->translations) == 0);
+    assert(pool_elts(pm->interfaces) == 0);
+}
+static void test_attach(void) {
+    pnat_attachment_point_t attachment = PNAT_IP4_INPUT;
+    u32 binding_index = 0;
+    u32 sw_if_index = 0;
+    int rv = pnat_binding_attach(sw_if_index, attachment, binding_index);
+    test_assert(rv == -1, "binding_attach - nothing to attach");
+
+    rv = pnat_binding_detach(sw_if_index, attachment, 1234);
+    test_assert(rv == -1, "binding_detach - nothing to detach");
+
+    pnat_5tuple_t match = {.mask = PNAT_SA};
+    pnat_5tuple_t rewrite = {.mask = PNAT_SA};
+    rv = pnat_binding_add(&match, &rewrite, &binding_index);
+    assert(rv == 0);
+
+    rv = pnat_binding_attach(sw_if_index, attachment, binding_index);
+    test_assert(rv == 0, "binding_attach - rule");
+
+    rv = pnat_binding_detach(sw_if_index, attachment, binding_index);
+    test_assert(rv == 0, "binding_detach - rule");
+
+    rv = pnat_binding_del(binding_index);
+    assert(rv == 0);
+}
+
+static void test_del_before_detach(void) {
+    pnat_attachment_point_t attachment = PNAT_IP4_INPUT;
+    u32 binding_index = 0;
+    u32 sw_if_index = 0;
+
+    /* Ensure 5-tuple here will not duplicate with other tests cause this will
+     * not be removed from flow cache */
+    rule_t rule = {
+        .match = {.dst = "123.123.123.123", .proto = 17, .dport = 6871},
+        .rewrite = {.dst = "1.2.3.4"},
+        .in = true,
+    };
+
+    add_translation(&rule);
+
+    int rv = pnat_binding_del(binding_index);
+    assert(rv == 0);
+
+    test_t test = {
+        .name = "hit missing rule",
+        .send = {"1.1.1.1", "123.123.123.123", 17, 80, 6871},
+        .expect = {"1.1.1.1", "123.123.123.123", 17, 80, 6871},
+        .expect_next_index = PNAT_NEXT_DROP,
+    };
+
+    test_table(&test, 1);
+
+    /* For now if you have deleted before detach, can't find key */
+    rv = pnat_binding_detach(sw_if_index, attachment, binding_index);
+    test_assert(rv == -1, "binding_detach - failure");
+
+    /* Re-add the rule and try again */
+    pnat_5tuple_t match = {0};
+    pnat_5tuple_t rewrite = {0};
+    ruleto5tuple(&rule.match, &match);
+    ruleto5tuple(&rule.rewrite, &rewrite);
+    rv = pnat_binding_add(&match, &rewrite, &binding_index);
+    assert(rv == 0);
+    rv = pnat_binding_detach(sw_if_index, attachment, binding_index);
+    test_assert(rv == 0, "binding_detach - pass");
+    rv = pnat_binding_del(binding_index);
+    assert(rv == 0);
+}
+
+static void test_api(void) {
+    test_attach();
+    test_del_before_detach();
+}
+
+/*
+ * Unit testing:
+ * 1) Table of packets and expected outcomes. Run through
+ * 2) Performance tests. Measure instructions, cache behaviour etc.
+ */
+clib_error_t *ip_checksum_init(vlib_main_t *vm);
+
+int main(int argc, char **argv) {
+
+    clib_mem_init(0, 3ULL << 30);
+
+    vlib_main_t *vm = &vlib_global_main;
+
+    buffers_vector = buffer_init(buffers_vector, 256);
+
+    assert(vlib_node_main_init(vm) == 0);
+
+    ip_checksum_init(vm);
+
+    u32 node_index = vlib_register_node(vm, &pnat_input_node);
+    node = vlib_node_get_runtime(vm, node_index);
+    assert(node);
+
+    /* Test API */
+    test_api();
+
+    test_packets();
+
+    test_performance();
+}