nat: refactor of port/address allocation functions

Change-Id: Ie2a3c0f44322dd8415603b7ce51bb72d72769c95
Ticket: VPP-1815
Type: refactor
Signed-off-by: Filip Varga <fivarga@cisco.com>

8 files changed, 429 insertions, 15 deletions

diff --git a/src/plugins/nat/CMakeLists.txt b/src/plugins/nat/CMakeLists.txt
index 372bbd61bb3..edba893cafe 100644
--- a/src/plugins/nat/CMakeLists.txt
+++ b/src/plugins/nat/CMakeLists.txt
@@ -11,6 +11,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+set(NAT_SRCS
+  lib/alloc.c
+)
+
+set(NAT_HEADERS
+  lib/alloc.h
+)
+
+add_vpp_library(nat
+  SOURCES ${NAT_SRCS}
+  LINK_LIBRARIES m
+  INSTALL_HEADERS ${NAT_HEADERS}
+  COMPONENT libnat
+)
+
 add_vpp_plugin(nat
   SOURCES
   nat.c
diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 7eaaab29544..8d6f124f51b 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -28,7 +28,7 @@
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
 #include <nat/nat_inlines.h>
-#include <nat/nat44_inlines.h>
+#include <nat/nat44/inlines.h>
 #include <nat/nat_syslog.h>
 #include <nat/nat_ha.h>
 
@@ -267,7 +267,7 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
   nat44_session_try_cleanup (&ip0->src_address, rx_fib_index0, thread_index,
 			     now);
 
-  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
     {
       b0->error = node->errors[SNAT_IN2OUT_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
diff --git a/src/plugins/nat/in2out_ed.c b/src/plugins/nat/in2out_ed.c
index 0209a4059db..ebcd29852bb 100644
--- a/src/plugins/nat/in2out_ed.c
+++ b/src/plugins/nat/in2out_ed.c
@@ -28,7 +28,7 @@
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
 #include <nat/nat_inlines.h>
-#include <nat/nat44_inlines.h>
+#include <nat/nat44/inlines.h>
 #include <nat/nat_syslog.h>
 #include <nat/nat_ha.h>
 
@@ -211,7 +211,7 @@ slow_path_ed (snat_main_t * sm,
 
   nat44_session_try_cleanup (&key->l_addr, rx_fib_index, thread_index, now);
 
-  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
     {
       b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
@@ -685,7 +685,7 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
     }
   else
     {
-      if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+      if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 	{
 	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 	  nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
diff --git a/src/plugins/nat/lib/alloc.c b/src/plugins/nat/lib/alloc.c
new file mode 100644
index 00000000000..2c9841b7b63
--- /dev/null
+++ b/src/plugins/nat/lib/alloc.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright (c) 2020 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.
+ */
+/**
+ * @file
+ * @brief NAT port/address allocation lib
+ */
+
+#include <nat/lib/alloc.h>
+
+static_always_inline void
+nat_ip4_addr_increment (ip4_address_t * addr)
+{
+  u32 v;
+  v = clib_net_to_host_u32 (addr->as_u32) + 1;
+  addr->as_u32 = clib_host_to_net_u32 (v);
+}
+
+int
+nat_add_del_ip4_pool_addr (nat_ip4_pool_t * pool, ip4_address_t addr,
+			   u8 is_add)
+{
+  int i;
+  nat_ip4_pool_addr_t *a = 0;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+
+  // lookup for the address
+  for (i = 0; i < vec_len (pool); i++)
+    {
+      if (pool->pool_addr[i].addr.as_u32 == addr.as_u32)
+	{
+	  a = pool->pool_addr + 1;
+	  break;
+	}
+    }
+  if (is_add)
+    {
+      if (a)
+	return NAT_ERROR_VALUE_EXIST;
+      vec_add2 (pool->pool_addr, a, 1);
+      a->addr = addr;
+#define _(N, i, n, s) \
+      clib_bitmap_alloc (a->busy_##n##_port_bitmap, 65535); \
+      a->busy_##n##_ports = 0; \
+      vec_validate_init_empty (a->busy_##n##_ports_per_thread, tm->n_vlib_mains - 1, 0);
+      foreach_nat_protocol
+#undef _
+    }
+  else
+    {
+      if (!a)
+	return NAT_ERROR_NO_SUCH_ENTRY;
+#define _(N, id, n, s) \
+      clib_bitmap_free (a->busy_##n##_port_bitmap); \
+      vec_free (a->busy_##n##_ports_per_thread);
+      foreach_nat_protocol
+#undef _
+	vec_del1 (pool->pool_addr, i);
+    }
+  return 0;
+}
+
+int
+nat_add_del_ip4_pool_addrs (nat_ip4_pool_t * pool,
+			    ip4_address_t addr, u32 count, u8 is_add,
+			    void *opaque)
+{
+  int i, rv;
+
+  for (i = 0; i < count; i++)
+    {
+      // TODO:
+      // a) consider if we could benefit from pre and post cb
+      // b) consider if we could benefit from add/del cb separation
+
+      // pre call:
+      // pool->add_del_pool_addr_pre_cb (&addr, is_add, opaque);
+
+      if ((rv = nat_add_del_ip4_pool_addr (pool, addr, is_add)) != 0)
+	return rv;
+
+      // post call:
+      // pool->add_del_pool_addr_post_cb (&addr, is_add, opaque);
+
+      pool->add_del_pool_addr_cb (addr, is_add, opaque);
+      nat_ip4_addr_increment (&addr);
+    }
+
+  return 0;
+}
+
+static_always_inline u16
+nat_random_port (u32 random_seed, u16 min, u16 max)
+{
+  return min + random_u32 (&random_seed) /
+    (random_u32_max () / (max - min + 1) + 1);
+}
+
+int
+nat_alloc_ip4_addr_and_port_cb_default (nat_ip4_pool_t * pool,
+					u32 fib_index,
+					u32 thread_index,
+					u32 nat_thread_index,
+					u16 port_per_thread,
+					u16 protocol,
+					nat_ip4_addr_port_t * out)
+{
+  nat_ip4_pool_addr_t *a, *ga = 0;
+  u32 i;
+  u32 portnum;
+
+  for (i = 0; i < vec_len (pool->pool_addr); i++)
+    {
+      a = pool->pool_addr + i;
+      switch (protocol)
+	{
+#define _(N, j, n, s) \
+        case NAT_PROTOCOL_##N: \
+          if (a->busy_##n##_ports_per_thread[thread_index] < port_per_thread) \
+            { \
+              if (a->fib_index == fib_index) \
+                { \
+                  while (1) \
+                    { \
+                      portnum = (port_per_thread * \
+                        nat_thread_index) + \
+                        nat_random_port(pool->random_seed, 1, port_per_thread) + 1024; \
+                      if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+                        continue; \
+                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+                      a->busy_##n##_ports_per_thread[thread_index]++; \
+                      a->busy_##n##_ports++; \
+                      out->addr = a->addr; \
+                      out->port = clib_host_to_net_u16(portnum); \
+                      return 0; \
+                    } \
+                } \
+              else if (a->fib_index == ~0) \
+                { \
+                  ga = a; \
+                } \
+            } \
+          break;
+	  foreach_nat_protocol
+#undef _
+	default:
+	  return NAT_ERROR_UNKNOWN_PROTOCOL;
+	}
+
+    }
+  if (ga)
+    {
+      a = ga;
+      switch (protocol)
+	{
+#define _(N, j, n, s) \
+        case NAT_PROTOCOL_##N: \
+          while (1) \
+            { \
+              portnum = (port_per_thread * \
+                nat_thread_index) + \
+                nat_random_port(pool->random_seed, 1, port_per_thread) + 1024; \
+              if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+                continue; \
+              clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+              a->busy_##n##_ports_per_thread[thread_index]++; \
+              a->busy_##n##_ports++; \
+              out->addr = a->addr; \
+              out->port = clib_host_to_net_u16(portnum); \
+              return 0; \
+            }
+	  break;
+	  foreach_nat_protocol
+#undef _
+	default:
+	  return NAT_ERROR_UNKNOWN_PROTOCOL;
+	}
+    }
+  return NAT_ERROR_OUT_OF_TRANSLATIONS;
+}
+
+int
+nat_alloc_ip4_addr_and_port (nat_ip4_pool_t * pool,
+			     u32 fib_index,
+			     u32 thread_index,
+			     u32 nat_thread_index,
+			     u16 port_per_thread,
+			     u16 protocol, nat_ip4_addr_port_t * out)
+{
+  return pool->alloc_addr_and_port_cb (pool,
+				       fib_index,
+				       thread_index,
+				       nat_thread_index,
+				       port_per_thread, protocol, out);
+}
+
+// TODO: consider using standard u16 port and ip4_address_t as input ?
+int
+nat_free_ip4_addr_and_port (nat_ip4_pool_t * pool,
+			    u32 thread_index,
+			    u16 protocol, nat_ip4_addr_port_t * addr_port)
+{
+  nat_ip4_pool_addr_t *a = 0;
+  u32 i;
+  u16 port = clib_net_to_host_u16 (addr_port->port);
+
+  for (i = 0; i < vec_len (pool->pool_addr); i++)
+    {
+      if (pool->pool_addr[i].addr.as_u32 == addr_port->addr.as_u32)
+	{
+	  a = pool->pool_addr + i;
+	  break;
+	}
+    }
+
+  if (!a)
+    {
+      return NAT_ERROR_NO_SUCH_ENTRY;
+    }
+
+  switch (protocol)
+    {
+#define _(N, i, n, s) \
+    case NAT_PROTOCOL_##N: \
+      ASSERT (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, \
+        port) == 1); \
+      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, \
+        port, 0); \
+      a->busy_##n##_ports--; \
+      a->busy_##n##_ports_per_thread[thread_index]--; \
+      break;
+      foreach_nat_protocol
+#undef _
+    default:
+      return NAT_ERROR_UNKNOWN_PROTOCOL;
+    }
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/lib/alloc.h b/src/plugins/nat/lib/alloc.h
new file mode 100644
index 00000000000..9dba2ca94da
--- /dev/null
+++ b/src/plugins/nat/lib/alloc.h
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2020 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.
+ */
+/**
+ * @file
+ * @brief NAT port/address allocation lib
+ */
+
+#ifndef included_nat_lib_alloc_h__
+#define included_nat_lib_alloc_h__
+
+#include <vnet/ip/ip.h>
+
+#define foreach_nat_error \
+  _(VALUE_EXIST, -1, "Value already exists") \
+  _(NO_SUCH_ENTRY, -2, "No such entry") \
+  _(UNKNOWN_PROTOCOL, -3, "Unknown protocol") \
+  _(OUT_OF_TRANSLATIONS, -4, "Out of translations")
+
+#define foreach_nat_protocol \
+  _(UDP, 0, udp, "udp")       \
+  _(TCP, 1, tcp, "tcp")       \
+  _(ICMP, 2, icmp, "icmp")
+
+typedef enum
+{
+#define _(N, i, s) NAT_ERROR_##N = i,
+  foreach_nat_error
+#undef _
+} nat_error_t;
+
+typedef enum
+{
+#define _(N, i, n, s) NAT_PROTOCOL_##N = i,
+  foreach_nat_protocol
+#undef _
+} nat_protocol_t;
+
+typedef struct nat_ip4_pool_addr_s nat_ip4_pool_addr_t;
+typedef struct nat_ip4_addr_port_s nat_ip4_addr_port_t;
+typedef struct nat_ip4_pool_s nat_ip4_pool_t;
+
+typedef void (nat_add_del_ip4_pool_addr_cb_t) (ip4_address_t addr,
+					       u8 is_add, void *opaque);
+
+typedef int (nat_alloc_ip4_addr_and_port_cb_t) (nat_ip4_pool_t * pool,
+						u32 fib_index,
+						u32 thread_index,
+						u32 nat_thread_index,
+						u16 port_per_thread,
+						u16 protocol,
+						nat_ip4_addr_port_t * out);
+
+struct nat_ip4_pool_addr_s
+{
+  ip4_address_t addr;
+  u32 fib_index;
+/* *INDENT-OFF* */
+#define _(N, i, n, s) \
+  u16 busy_##n##_ports; \
+  u16 * busy_##n##_ports_per_thread; \
+  uword * busy_##n##_port_bitmap;
+  foreach_nat_protocol
+#undef _
+/* *INDENT-ON* */
+};
+
+struct nat_ip4_addr_port_s
+{
+  ip4_address_t addr;
+  u16 port;
+};
+
+struct nat_ip4_pool_s
+{
+  nat_add_del_ip4_pool_addr_cb_t *add_del_pool_addr_cb;
+  nat_alloc_ip4_addr_and_port_cb_t *alloc_addr_and_port_cb;
+  nat_ip4_pool_addr_t *pool_addr;
+  u32 random_seed;
+};
+
+int
+nat_add_del_ip4_pool_addr (nat_ip4_pool_t * pool,
+			   ip4_address_t addr, u8 is_add);
+
+int
+nat_add_del_ip4_pool_addrs (nat_ip4_pool_t * pool,
+			    ip4_address_t addr,
+			    u32 count, u8 is_add, void *opaque);
+
+int
+nat_alloc_ip4_addr_and_port_cb_default (nat_ip4_pool_t * pool,
+					u32 fib_index,
+					u32 thread_index,
+					u32 nat_thread_index,
+					u16 port_per_thread,
+					u16 protocol,
+					nat_ip4_addr_port_t * out);
+
+int
+nat_alloc_ip4_addr_and_port (nat_ip4_pool_t * pool,
+			     u32 fib_index,
+			     u32 thread_index,
+			     u32 nat_thread_index,
+			     u16 port_per_thread,
+			     u16 protocol, nat_ip4_addr_port_t * out);
+
+int
+nat_free_ip4_addr_and_port (nat_ip4_pool_t * pool,
+			    u32 thread_index,
+			    u16 protocol, nat_ip4_addr_port_t * in);
+
+#endif /* included_nat_lib_alloc_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/nat44_inlines.h b/src/plugins/nat/nat44/inlines.h
index eb1077cdf34..a7bb469b464 100644
--- a/src/plugins/nat/nat44_inlines.h
+++ b/src/plugins/nat/nat44/inlines.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Copyright (c) 2020 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:
@@ -15,12 +15,22 @@
 /**
  * @brief The NAT44 inline functions
  */
-#ifndef __included_nat44_inlines_h__
-#define __included_nat44_inlines_h__
+
+#ifndef included_nat44_inlines_h__
+#define included_nat44_inlines_h__
 
 #include <vnet/fib/ip4_fib.h>
 #include <nat/nat.h>
 
+static_always_inline u8
+nat44_maximum_sessions_exceeded (snat_main_t * sm, u32 thread_index)
+{
+  if (pool_elts (sm->per_thread_data[thread_index].sessions) >=
+      sm->max_translations)
+    return 1;
+  return 0;
+}
+
 static_always_inline void
 nat44_session_cleanup (snat_session_t * s, u32 thread_index)
 {
@@ -98,7 +108,7 @@ nat44_session_try_cleanup (ip4_address_t * addr,
 			  thread_index, now);
 }
 
-#endif /* __included_nat44_inlines_h__ */
+#endif /* included_nat44_inlines_h__ */
 
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index e9ca88f1d68..144f324dbf4 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -28,7 +28,7 @@
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
 #include <nat/nat_inlines.h>
-#include <nat/nat44_inlines.h>
+#include <nat/nat44/inlines.h>
 #include <nat/nat_syslog.h>
 #include <nat/nat_ha.h>
 
@@ -191,7 +191,7 @@ create_session_for_static_mapping (snat_main_t * sm,
   nat44_session_try_cleanup (&in2out.addr, in2out.fib_index, thread_index,
 			     now);
 
-  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
     {
       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_elog_notice ("maximum sessions exceeded");
diff --git a/src/plugins/nat/out2in_ed.c b/src/plugins/nat/out2in_ed.c
index ee2f85aa080..7cb205f6d6f 100644
--- a/src/plugins/nat/out2in_ed.c
+++ b/src/plugins/nat/out2in_ed.c
@@ -28,7 +28,7 @@
 #include <nat/nat.h>
 #include <nat/nat_ipfix_logging.h>
 #include <nat/nat_inlines.h>
-#include <nat/nat44_inlines.h>
+#include <nat/nat44/inlines.h>
 #include <nat/nat_syslog.h>
 #include <nat/nat_ha.h>
 
@@ -205,7 +205,7 @@ create_session_for_static_mapping_ed (snat_main_t * sm,
 
   nat44_session_try_cleanup (&l_key.addr, l_key.fib_index, thread_index, now);
 
-  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
     {
       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_elog_notice ("maximum sessions exceeded");
@@ -369,7 +369,7 @@ create_bypass_for_fwd (snat_main_t * sm, vlib_buffer_t * b, ip4_header_t * ip,
     {
       u32 proto;
 
-      if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+      if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 	return;
 
       u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index,
@@ -592,7 +592,7 @@ nat44_ed_out2in_unknown_proto (snat_main_t * sm,
     }
   else
     {
-      if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+      if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 	{
 	  b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 	  nat_elog_notice ("maximum sessions exceeded");