misc: Move l2tp to plugin

Type: refactor

Change-Id: Ifb36eeb146b87e9e305881429d32d6879e955e1e
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 301 insertions, 0 deletions

diff --git a/src/plugins/l2tp/decap.c b/src/plugins/l2tp/decap.c
new file mode 100644
index 00000000000..8c41bdd2357
--- /dev/null
+++ b/src/plugins/l2tp/decap.c
@@ -0,0 +1,301 @@
+/*
+ * decap.c : L2TPv3 tunnel decapsulation
+ *
+ * Copyright (c) 2013 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 <vppinfra/error.h>
+#include <vppinfra/hash.h>
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vnet/ethernet/ethernet.h>
+#include <l2tp/l2tp.h>
+#include <vnet/l2/l2_input.h>
+
+/* Statistics (not really errors) */
+#define foreach_l2t_decap_error                                 \
+_(USER_TO_NETWORK, "L2TP user (ip6) to L2 network pkts")        \
+_(SESSION_ID_MISMATCH, "l2tpv3 local session id mismatches")    \
+_(COOKIE_MISMATCH, "l2tpv3 local cookie mismatches")            \
+_(NO_SESSION, "l2tpv3 session not found")                       \
+_(ADMIN_DOWN, "l2tpv3 tunnel is down")
+
+static char *l2t_decap_error_strings[] = {
+#define _(sym,string) string,
+  foreach_l2t_decap_error
+#undef _
+};
+
+typedef enum
+{
+#define _(sym,str) L2T_DECAP_ERROR_##sym,
+  foreach_l2t_decap_error
+#undef _
+    L2T_DECAP_N_ERROR,
+} l2t_DECAP_error_t;
+
+typedef enum
+{
+  L2T_DECAP_NEXT_DROP,
+  L2T_DECAP_NEXT_L2_INPUT,
+  L2T_DECAP_N_NEXT,
+  /* Pseudo next index */
+  L2T_DECAP_NEXT_NO_INTERCEPT = L2T_DECAP_N_NEXT,
+} l2t_decap_next_t;
+
+#define NSTAGES 3
+
+static inline void
+stage0 (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b)
+{
+  vlib_prefetch_buffer_header (b, STORE);
+  /* l2tpv3 header is a long way away, need 2 cache lines */
+  CLIB_PREFETCH (b->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
+}
+
+static inline void
+stage1 (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b)
+{
+  l2t_main_t *lm = &l2t_main;
+  ip6_header_t *ip6 = vlib_buffer_get_current (b);
+  u32 session_index;
+  uword *p = 0;
+  l2tpv3_header_t *l2t;
+
+  /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */
+  if (PREDICT_FALSE (ip6->protocol != IP_PROTOCOL_L2TP))
+    {
+      vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
+      return;
+    }
+
+  /* Make up your minds, people... */
+  switch (lm->lookup_type)
+    {
+    case L2T_LOOKUP_SRC_ADDRESS:
+      p = hash_get_mem (lm->session_by_src_address, &ip6->src_address);
+      break;
+    case L2T_LOOKUP_DST_ADDRESS:
+      p = hash_get_mem (lm->session_by_dst_address, &ip6->dst_address);
+      break;
+    case L2T_LOOKUP_SESSION_ID:
+      l2t = (l2tpv3_header_t *) (ip6 + 1);
+      p = hash_get (lm->session_by_session_id, l2t->session_id);
+      break;
+    default:
+      ASSERT (0);
+    }
+
+  if (PREDICT_FALSE (p == 0))
+    {
+      vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
+      return;
+    }
+  else
+    {
+      session_index = p[0];
+    }
+
+  /* Remember mapping index, prefetch the mini counter */
+  vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_L2_INPUT;
+  vnet_buffer (b)->l2t.session_index = session_index;
+
+  /* $$$$$ prefetch counter */
+}
+
+static inline u32
+last_stage (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b)
+{
+  l2t_main_t *lm = &l2t_main;
+  ip6_header_t *ip6 = vlib_buffer_get_current (b);
+  vlib_node_t *n = vlib_get_node (vm, node->node_index);
+  u32 node_counter_base_index = n->error_heap_index;
+  vlib_error_main_t *em = &vm->error_main;
+  l2tpv3_header_t *l2tp;
+  u32 counter_index;
+  l2t_session_t *session = 0;
+  u32 session_index;
+  u32 next_index;
+  u8 l2tp_decap_local = (l2t_decap_local_node.index == n->index);
+
+  /* Other-than-output pkt? We're done... */
+  if (vnet_buffer (b)->l2t.next_index != L2T_DECAP_NEXT_L2_INPUT)
+    {
+      next_index = vnet_buffer (b)->l2t.next_index;
+      goto done;
+    }
+
+  em->counters[node_counter_base_index + L2T_DECAP_ERROR_USER_TO_NETWORK] +=
+    1;
+
+  session_index = vnet_buffer (b)->l2t.session_index;
+
+  counter_index =
+    session_index_to_counter_index (session_index,
+				    SESSION_COUNTER_USER_TO_NETWORK);
+
+  /* per-mapping byte stats include the ethernet header */
+  vlib_increment_combined_counter (&lm->counter_main,
+				   vlib_get_thread_index (),
+				   counter_index, 1 /* packet_increment */ ,
+				   vlib_buffer_length_in_chain (vm, b) +
+				   sizeof (ethernet_header_t));
+
+  session = pool_elt_at_index (lm->sessions, session_index);
+
+  l2tp = vlib_buffer_get_current (b) + sizeof (*ip6);
+
+  if (PREDICT_FALSE (l2tp->session_id != session->local_session_id))
+    {
+      /* Key matched but session id does not. Assume packet is not for us. */
+      em->counters[node_counter_base_index +
+		   L2T_DECAP_ERROR_SESSION_ID_MISMATCH] += 1;
+      next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
+      goto done;
+    }
+
+  if (PREDICT_FALSE (l2tp->cookie != session->local_cookie[0]))
+    {
+      if (l2tp->cookie != session->local_cookie[1])
+	{
+	  /* Key and session ID matched, but cookie doesn't. Drop this packet. */
+	  b->error = node->errors[L2T_DECAP_ERROR_COOKIE_MISMATCH];
+	  next_index = L2T_DECAP_NEXT_DROP;
+	  goto done;
+	}
+    }
+
+  vnet_buffer (b)->sw_if_index[VLIB_RX] = session->sw_if_index;
+
+  if (PREDICT_FALSE (!(session->admin_up)))
+    {
+      b->error = node->errors[L2T_DECAP_ERROR_ADMIN_DOWN];
+      next_index = L2T_DECAP_NEXT_DROP;
+      goto done;
+    }
+
+  /* strip the ip6 and L2TP header */
+  vlib_buffer_advance (b, sizeof (*ip6) + session->l2tp_hdr_size);
+
+  /* Required to make the l2 tag push / pop code work on l2 subifs */
+  vnet_update_l2_len (b);
+
+  if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
+    {
+      l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
+      t->is_user_to_network = 1;
+      t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
+      t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
+      t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
+      t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
+      t->session_index = session_index;
+    }
+
+  return L2T_DECAP_NEXT_L2_INPUT;
+
+done:
+  if (next_index == L2T_DECAP_NEXT_NO_INTERCEPT)
+    {
+      /* Small behavioral change between l2tp-decap and l2tp-decap-local */
+      if (l2tp_decap_local)
+	{
+	  b->error = node->errors[L2T_DECAP_ERROR_NO_SESSION];
+	  next_index = L2T_DECAP_NEXT_DROP;
+	}
+      else
+	{
+	  /* Go to next node on the ip6 configuration chain */
+	  if (PREDICT_TRUE (session != 0))
+	    vnet_feature_next (&next_index, b);
+	}
+    }
+
+  if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
+    {
+      l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
+      t->is_user_to_network = 1;
+      t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
+      t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
+      t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
+      t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
+      t->session_index = ~0;
+    }
+  return next_index;
+}
+
+#include <vnet/pipeline.h>
+
+VLIB_NODE_FN (l2t_decap_node) (vlib_main_t * vm,
+			       vlib_node_runtime_t * node,
+			       vlib_frame_t * frame)
+{
+  return dispatch_pipeline (vm, node, frame);
+}
+
+/*
+ * l2tp-decap and l2tp-decap-local have very slightly different behavior.
+ * When a packet has no associated session l2tp-decap let it go to ip6 forward,
+ * while l2tp-decap-local drops it.
+ */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (l2t_decap_node) = {
+  .name = "l2tp-decap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_l2t_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(l2t_decap_error_strings),
+  .error_strings = l2t_decap_error_strings,
+
+  .n_next_nodes = L2T_DECAP_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+        [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
+        [L2T_DECAP_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+extern vlib_node_function_t l2t_decap_node_fn;
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (l2t_decap_local_node) = {
+  .function = l2t_decap_node_fn,
+  .name = "l2tp-decap-local",
+  .vector_size = sizeof (u32),
+  .format_trace = format_l2t_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(l2t_decap_error_strings),
+  .error_strings = l2t_decap_error_strings,
+
+  .n_next_nodes = L2T_DECAP_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
+    [L2T_DECAP_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */