NAT44: client-IP based session affinity for load-balancing (VPP-1297)

Enable client-IP based session affinity per LB NAT rule with specific timeout.

Change-Id: I9aade152e330218d21dfda99cc5e984d769ab806
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 269 insertions, 0 deletions

diff --git a/src/plugins/nat/nat_affinity.c b/src/plugins/nat/nat_affinity.c
new file mode 100644
index 00000000000..28c25aecda5
--- /dev/null
+++ b/src/plugins/nat/nat_affinity.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright (c) 2018 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 plugin client-IP based session affinity for load-balancing
+ */
+
+#include <nat/nat_affinity.h>
+#include <nat/nat.h>
+
+nat_affinity_main_t nat_affinity_main;
+
+#define AFFINITY_HASH_BUCKETS 65536
+#define AFFINITY_HASH_MEMORY (2 << 25)
+
+u8 *
+format_affinity_kvp (u8 * s, va_list * args)
+{
+  clib_bihash_kv_16_8_t *v = va_arg (*args, clib_bihash_kv_16_8_t *);
+  nat_affinity_key_t k;
+
+  k.as_u64[0] = v->key[0];
+  k.as_u64[1] = v->key[1];
+
+  s = format (s, "client %U backend %U:%d proto %U index %llu",
+	      format_ip4_address, &k.client_addr,
+	      format_ip4_address, &k.service_addr,
+	      clib_net_to_host_u16 (k.service_port),
+	      format_snat_protocol, k.proto);
+
+  return s;
+}
+
+clib_error_t *
+nat_affinity_init (vlib_main_t * vm)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+  clib_error_t *error = 0;
+
+  if (tm->n_vlib_mains > 1)
+    clib_spinlock_init (&nam->affinity_lock);
+
+  clib_bihash_init_16_8 (&nam->affinity_hash, "nat-affinity",
+			 AFFINITY_HASH_BUCKETS, AFFINITY_HASH_MEMORY);
+  clib_bihash_set_kvp_format_fn_16_8 (&nam->affinity_hash,
+				      format_affinity_kvp);
+
+  nam->vlib_main = vm;
+
+  return error;
+}
+
+static_always_inline void
+make_affinity_kv (clib_bihash_kv_16_8_t * kv, ip4_address_t client_addr,
+		  ip4_address_t service_addr, u8 proto, u16 service_port)
+{
+  nat_affinity_key_t *key = (nat_affinity_key_t *) kv->key;
+
+  key->client_addr = client_addr;
+  key->service_addr = service_addr;
+  key->proto = proto;
+  key->service_port = service_port;
+
+  kv->value = ~0ULL;
+}
+
+u32
+nat_affinity_get_per_service_list_head_index (void)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  dlist_elt_t *head_elt;
+
+  clib_spinlock_lock_if_init (&nam->affinity_lock);
+
+  pool_get (nam->list_pool, head_elt);
+  clib_dlist_init (nam->list_pool, head_elt - nam->list_pool);
+
+  clib_spinlock_unlock_if_init (&nam->affinity_lock);
+
+  return head_elt - nam->list_pool;
+}
+
+void
+nat_affinity_flush_service (u32 affinity_per_service_list_head_index)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  u32 elt_index;
+  dlist_elt_t *elt;
+  nat_affinity_t *a;
+  clib_bihash_kv_16_8_t kv;
+
+  clib_spinlock_lock_if_init (&nam->affinity_lock);
+
+  while ((elt_index =
+	  clib_dlist_remove_head (nam->list_pool,
+				  affinity_per_service_list_head_index)) !=
+	 ~0)
+    {
+      elt = pool_elt_at_index (nam->list_pool, elt_index);
+      a = pool_elt_at_index (nam->affinity_pool, elt->value);
+      kv.key[0] = a->key.as_u64[0];
+      kv.key[1] = a->key.as_u64[1];
+      pool_put_index (nam->affinity_pool, elt->value);
+      if (clib_bihash_add_del_16_8 (&nam->affinity_hash, &kv, 0))
+	nat_log_warn ("affinity key del failed");
+      pool_put_index (nam->list_pool, elt_index);
+    }
+  pool_put_index (nam->list_pool, affinity_per_service_list_head_index);
+
+  clib_spinlock_unlock_if_init (&nam->affinity_lock);
+}
+
+int
+nat_affinity_find_and_lock (ip4_address_t client_addr,
+			    ip4_address_t service_addr, u8 proto,
+			    u16 service_port, u8 * backend_index)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  clib_bihash_kv_16_8_t kv, value;
+  nat_affinity_t *a;
+  int rv = 0;
+
+  make_affinity_kv (&kv, client_addr, service_addr, proto, service_port);
+  clib_spinlock_lock_if_init (&nam->affinity_lock);
+  if (clib_bihash_search_16_8 (&nam->affinity_hash, &kv, &value))
+    {
+      rv = 1;
+      goto unlock;
+    }
+
+  a = pool_elt_at_index (nam->affinity_pool, value.value);
+  /* if already expired delete */
+  if (a->ref_cnt == 0)
+    {
+      if (a->expire < vlib_time_now (nam->vlib_main))
+	{
+	  clib_dlist_remove (nam->list_pool, a->per_service_index);
+	  pool_put_index (nam->list_pool, a->per_service_index);
+	  pool_put_index (nam->affinity_pool, value.value);
+	  if (clib_bihash_add_del_16_8 (&nam->affinity_hash, &kv, 0))
+	    nat_log_warn ("affinity key del failed");
+	  rv = 1;
+	  goto unlock;
+	}
+    }
+  a->ref_cnt++;
+  *backend_index = a->backend_index;
+
+unlock:
+  clib_spinlock_unlock_if_init (&nam->affinity_lock);
+  return rv;
+}
+
+static int
+affinity_is_expired_cb (clib_bihash_kv_16_8_t * kv, void *arg)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  nat_affinity_t *a;
+
+  a = pool_elt_at_index (nam->affinity_pool, kv->value);
+  if (a->ref_cnt == 0)
+    {
+      if (a->expire < vlib_time_now (nam->vlib_main))
+	{
+	  clib_dlist_remove (nam->list_pool, a->per_service_index);
+	  pool_put_index (nam->list_pool, a->per_service_index);
+	  pool_put_index (nam->affinity_pool, kv->value);
+	  if (clib_bihash_add_del_16_8 (&nam->affinity_hash, kv, 0))
+	    nat_log_warn ("affinity key del failed");
+	  return 1;
+	}
+    }
+
+  return 0;
+}
+
+int
+nat_affinity_create_and_lock (ip4_address_t client_addr,
+			      ip4_address_t service_addr, u8 proto,
+			      u16 service_port, u8 backend_index,
+			      u32 sticky_time,
+			      u32 affinity_per_service_list_head_index)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  clib_bihash_kv_16_8_t kv, value;
+  nat_affinity_t *a;
+  dlist_elt_t *list_elt;
+  int rv = 0;
+
+  make_affinity_kv (&kv, client_addr, service_addr, proto, service_port);
+  clib_spinlock_lock_if_init (&nam->affinity_lock);
+  if (!clib_bihash_search_16_8 (&nam->affinity_hash, &kv, &value))
+    {
+      rv = 1;
+      nat_log_notice ("affinity key already exist");
+      goto unlock;
+    }
+
+  pool_get (nam->affinity_pool, a);
+  kv.value = a - nam->affinity_pool;
+  rv =
+    clib_bihash_add_or_overwrite_stale_16_8 (&nam->affinity_hash, &kv,
+					     affinity_is_expired_cb, NULL);
+  if (rv)
+    {
+      nat_log_notice ("affinity key add failed");
+      pool_put (nam->affinity_pool, a);
+      goto unlock;
+    }
+
+  pool_get (nam->list_pool, list_elt);
+  clib_dlist_init (nam->list_pool, list_elt - nam->list_pool);
+  list_elt->value = a - nam->affinity_pool;
+  a->per_service_index = list_elt - nam->list_pool;
+  a->backend_index = backend_index;
+  a->ref_cnt = 1;
+  a->sticky_time = sticky_time;
+  a->key.as_u64[0] = kv.key[0];
+  a->key.as_u64[1] = kv.key[1];
+  clib_dlist_addtail (nam->list_pool, affinity_per_service_list_head_index,
+		      a->per_service_index);
+
+unlock:
+  clib_spinlock_unlock_if_init (&nam->affinity_lock);
+  return rv;
+}
+
+void
+nat_affinity_unlock (ip4_address_t client_addr, ip4_address_t service_addr,
+		     u8 proto, u16 service_port)
+{
+  nat_affinity_main_t *nam = &nat_affinity_main;
+  clib_bihash_kv_16_8_t kv, value;
+  nat_affinity_t *a;
+
+  make_affinity_kv (&kv, client_addr, service_addr, proto, service_port);
+  clib_spinlock_lock_if_init (&nam->affinity_lock);
+  if (clib_bihash_search_16_8 (&nam->affinity_hash, &kv, &value))
+    goto unlock;
+
+  a = pool_elt_at_index (nam->affinity_pool, value.value);
+  a->ref_cnt--;
+  if (a->ref_cnt == 0)
+    a->expire = (u64) a->sticky_time + vlib_time_now (nam->vlib_main);
+
+unlock:
+  clib_spinlock_unlock_if_init (&nam->affinity_lock);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */