nat: refactor of port/address allocation functions

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

2 files changed, 389 insertions, 0 deletions

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:
+ */