api: ip: add IP_ROUTE_LOOKUP API

Add an IP_ROUTE_LOOKUP function that does either an exact match or
longest prefix match in a given fib table for a given prefix
returning the match if present.

Add API test.

Type: improvement
Signed-off-by: Christian Hopps <chopps@labn.net>
Change-ID: I67ec5a61079f4acf1349a9c646185f91f5f11806

4 files changed, 231 insertions, 0 deletions

diff --git a/src/vnet/ip/ip.api b/src/vnet/ip/ip.api
index 5624bcfaf6a..42371c492ac 100644
--- a/src/vnet/ip/ip.api
+++ b/src/vnet/ip/ip.api
@@ -190,6 +190,32 @@ manual_endian manual_print define ip_route_details
   vl_api_ip_route_t route;
 };
 
+/** \brief Lookup IP route from a table
+    @param client_index - opaque cookie to identify the sender
+    @param table_id - The IP table to look the route up in
+    @param exact - 0 for normal route lookup, 1 for exact match only
+    @param prefix - The prefix (or host) for route lookup.
+*/
+define ip_route_lookup
+{
+  u32 client_index;
+  u32 context;
+  u32 table_id;
+  u8 exact;
+  vl_api_prefix_t prefix;
+};
+
+/** \brief IP FIB table lookup response
+    @param retval - return code of the lookup
+    @param route - The route entry in the table if found
+*/
+define ip_route_lookup_reply
+{
+  u32 context;
+  i32 retval;
+  vl_api_ip_route_t route;
+};
+
 /** \brief Set the ip flow hash config for a fib request
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
diff --git a/src/vnet/ip/ip_api.c b/src/vnet/ip/ip_api.c
index d5fa2d32f21..b976eaeaa6b 100644
--- a/src/vnet/ip/ip_api.c
+++ b/src/vnet/ip/ip_api.c
@@ -82,6 +82,7 @@ _(IP_TABLE_REPLACE_BEGIN, ip_table_replace_begin)                       \
 _(IP_TABLE_REPLACE_END, ip_table_replace_end)                           \
 _(IP_TABLE_FLUSH, ip_table_flush)                                       \
 _(IP_ROUTE_ADD_DEL, ip_route_add_del)                                   \
+_(IP_ROUTE_LOOKUP, ip_route_lookup)                                     \
 _(IP_TABLE_ADD_DEL, ip_table_add_del)                                   \
 _(IP_PUNT_POLICE, ip_punt_police)                                       \
 _(IP_PUNT_REDIRECT, ip_punt_redirect)                                   \
@@ -574,6 +575,62 @@ vl_api_ip_route_add_del_t_handler (vl_api_ip_route_add_del_t * mp)
 }
 
 void
+vl_api_ip_route_lookup_t_handler (vl_api_ip_route_lookup_t * mp)
+{
+  vl_api_ip_route_lookup_reply_t *rmp = NULL;
+  fib_route_path_t *rpaths = NULL, *rpath;
+  const fib_prefix_t *pfx = NULL;
+  fib_prefix_t lookup;
+  vl_api_fib_path_t *fp;
+  fib_node_index_t fib_entry_index;
+  u32 fib_index;
+  int npaths = 0;
+  int rv;
+
+  ip_prefix_decode (&mp->prefix, &lookup);
+  rv = fib_api_table_id_decode (lookup.fp_proto, ntohl (mp->table_id),
+				&fib_index);
+  if (PREDICT_TRUE (!rv))
+    {
+      if (mp->exact)
+	fib_entry_index = fib_table_lookup_exact_match (fib_index, &lookup);
+      else
+	fib_entry_index = fib_table_lookup (fib_index, &lookup);
+      if (fib_entry_index == FIB_NODE_INDEX_INVALID)
+	rv = VNET_API_ERROR_NO_SUCH_ENTRY;
+      else
+	{
+	  pfx = fib_entry_get_prefix (fib_entry_index);
+	  rpaths = fib_entry_encode (fib_entry_index);
+	  npaths = vec_len (rpaths);
+	}
+    }
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO3_ZERO(VL_API_IP_ROUTE_LOOKUP_REPLY,
+                    npaths * sizeof (*fp),
+  ({
+    if (!rv)
+      {
+        ip_prefix_encode (pfx, &rmp->route.prefix);
+        rmp->route.table_id = mp->table_id;
+        rmp->route.n_paths = npaths;
+        rmp->route.stats_index = fib_table_entry_get_stats_index (fib_index, pfx);
+        rmp->route.stats_index = htonl (rmp->route.stats_index);
+
+        fp = rmp->route.paths;
+        vec_foreach (rpath, rpaths)
+          {
+            fib_api_path_encode (rpath, fp);
+            fp++;
+          }
+      }
+  }));
+  /* *INDENT-ON* */
+  vec_free (rpaths);
+}
+
+void
 ip_table_create (fib_protocol_t fproto,
 		 u32 table_id, u8 is_api, const u8 * name)
 {
diff --git a/test/test_ip4.py b/test/test_ip4.py
index 6f8047cace9..43804c7c40a 100644
--- a/test/test_ip4.py
+++ b/test/test_ip4.py
@@ -214,6 +214,80 @@ class TestIPv4(VppTestCase):
             self.verify_capture(i, pkts)
 
 
+class TestIPv4RouteLookup(VppTestCase):
+    """ IPv4 Route Lookup Test Case """
+    routes = []
+
+    def route_lookup(self, prefix, exact):
+        return self.vapi.api(self.vapi.papi.ip_route_lookup,
+                             {
+                                 'table_id': 0,
+                                 'exact': exact,
+                                 'prefix': prefix,
+                             })
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestIPv4RouteLookup, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestIPv4RouteLookup, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestIPv4RouteLookup, self).setUp()
+
+        drop_nh = VppRoutePath("127.0.0.1", 0xffffffff,
+                               type=FibPathType.FIB_PATH_TYPE_DROP)
+
+        # Add 3 routes
+        r = VppIpRoute(self, "1.1.0.0", 16, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "1.1.1.0", 24, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "1.1.1.1", 32, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+    def tearDown(self):
+        # Remove the routes we added
+        for r in self.routes:
+            r.remove_vpp_config()
+
+        super(TestIPv4RouteLookup, self).tearDown()
+
+    def test_exact_match(self):
+        # Verify we find the host route
+        prefix = "1.1.1.1/32"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we find a middle prefix route
+        prefix = "1.1.1.0/24"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we do not find an available LPM.
+        with self.vapi.assert_negative_api_retval():
+            self.route_lookup("1.1.1.2/32", True)
+
+    def test_longest_prefix_match(self):
+        # verify we find lpm
+        lpm_prefix = "1.1.1.0/24"
+        result = self.route_lookup("1.1.1.2/32", False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Verify we find the exact when not requested
+        result = self.route_lookup(lpm_prefix, False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Can't seem to delete the default route so no negative LPM test.
+
+
 class TestIPv4IfAddrRoute(VppTestCase):
     """ IPv4 Interface Addr Route Test Case """
 
diff --git a/test/test_ip6.py b/test/test_ip6.py
index c92ebb5852a..87346c2964f 100644
--- a/test/test_ip6.py
+++ b/test/test_ip6.py
@@ -979,6 +979,80 @@ class TestIPv6(TestIPv6ND):
         self.assertEqual(mld.records_number, 4)
 
 
+class TestIPv6RouteLookup(VppTestCase):
+    """ IPv6 Route Lookup Test Case """
+    routes = []
+
+    def route_lookup(self, prefix, exact):
+        return self.vapi.api(self.vapi.papi.ip_route_lookup,
+                             {
+                                 'table_id': 0,
+                                 'exact': exact,
+                                 'prefix': prefix,
+                             })
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestIPv6RouteLookup, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestIPv6RouteLookup, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestIPv6RouteLookup, self).setUp()
+
+        drop_nh = VppRoutePath("::1", 0xffffffff,
+                               type=FibPathType.FIB_PATH_TYPE_DROP)
+
+        # Add 3 routes
+        r = VppIpRoute(self, "2001:1111::", 32, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "2001:1111:2222::", 48, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "2001:1111:2222::1", 128, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+    def tearDown(self):
+        # Remove the routes we added
+        for r in self.routes:
+            r.remove_vpp_config()
+
+        super(TestIPv6RouteLookup, self).tearDown()
+
+    def test_exact_match(self):
+        # Verify we find the host route
+        prefix = "2001:1111:2222::1/128"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we find a middle prefix route
+        prefix = "2001:1111:2222::/48"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we do not find an available LPM.
+        with self.vapi.assert_negative_api_retval():
+            self.route_lookup("2001::2/128", True)
+
+    def test_longest_prefix_match(self):
+        # verify we find lpm
+        lpm_prefix = "2001:1111:2222::/48"
+        result = self.route_lookup("2001:1111:2222::2/128", False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Verify we find the exact when not requested
+        result = self.route_lookup(lpm_prefix, False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Can't seem to delete the default route so no negative LPM test.
+
+
 class TestIPv6IfAddrRoute(VppTestCase):
     """ IPv6 Interface Addr Route Test Case """