ipv6 connection tracking plugin

A security feature: drop unsolicited global unicast traffic.

Change-Id: I421da7d52e08b7acf40c62a1f6e2a6caac349e7e
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 362 insertions, 0 deletions

diff --git a/src/plugins/ct6/ct6_in2out.c b/src/plugins/ct6/ct6_in2out.c
new file mode 100644
index 00000000000..b28d349dd29
--- /dev/null
+++ b/src/plugins/ct6/ct6_in2out.c
@@ -0,0 +1,362 @@
+/*
+ * ct6_in2out.c - ip6 connection tracker, inside-to-outside path
+ *
+ * Copyright (c) 2019 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <ct6/ct6.h>
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u32 session_index;
+} ct6_in2out_trace_t;
+
+#ifndef CLIB_MARCH_VARIANT
+
+/* packet trace format function */
+static u8 *
+format_ct6_in2out_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  ct6_in2out_trace_t *t = va_arg (*args, ct6_in2out_trace_t *);
+
+  s = format (s, "CT6_IN2OUT: sw_if_index %d, next index %d session %d\n",
+	      t->sw_if_index, t->next_index, t->session_index);
+  return s;
+}
+
+vlib_node_registration_t ct6_in2out_node;
+
+#endif /* CLIB_MARCH_VARIANT */
+
+#define foreach_ct6_in2out_error                \
+_(PROCESSED, "ct6 packets processed")           \
+_(CREATED, "ct6 sessions created")              \
+_(RECYCLED, "ct6 sessions recycled")
+
+typedef enum
+{
+#define _(sym,str) CT6_IN2OUT_ERROR_##sym,
+  foreach_ct6_in2out_error
+#undef _
+    CT6_IN2OUT_N_ERROR,
+} ct6_in2out_error_t;
+
+#ifndef CLIB_MARCH_VARIANT
+static char *ct6_in2out_error_strings[] = {
+#define _(sym,string) string,
+  foreach_ct6_in2out_error
+#undef _
+};
+#endif /* CLIB_MARCH_VARIANT */
+
+typedef enum
+{
+  CT6_IN2OUT_NEXT_DROP,
+  CT6_IN2OUT_N_NEXT,
+} ct6_next_t;
+
+#ifndef CLIB_MARCH_VARIANT
+ct6_session_t *
+ct6_create_or_recycle_session (ct6_main_t * cmp,
+			       clib_bihash_kv_48_8_t * kvpp, f64 now,
+			       u32 my_thread_index, u32 * recyclep,
+			       u32 * createp)
+{
+  ct6_session_t *s0;
+
+  /* Empty arena? */
+  if (PREDICT_FALSE (cmp->last_index[my_thread_index] == ~0))
+    goto alloc0;
+
+  /* Look at the least-recently-used session */
+  s0 = pool_elt_at_index (cmp->sessions[my_thread_index],
+			  cmp->last_index[my_thread_index]);
+
+  if (s0->expires < now)
+    clib_warning ("session %d expired %.2f time now %.2f",
+		  s0 - cmp->sessions[my_thread_index], s0->expires, now);
+
+  if (pool_elts (cmp->sessions[my_thread_index]) >=
+      cmp->max_sessions_per_worker)
+    clib_warning ("recycle session %d have %d max %d",
+		  s0 - cmp->sessions[my_thread_index],
+		  pool_elts (cmp->sessions[my_thread_index]),
+		  cmp->max_sessions_per_worker);
+
+  /* Session expired, or we have as many sessions as is allowed by law? */
+  if ((s0->expires < now) || (pool_elts (cmp->sessions[my_thread_index])
+			      >= cmp->max_sessions_per_worker))
+    {
+      /* recycle the session */
+      if (clib_bihash_add_del_48_8 (&cmp->session_hash,
+				    (clib_bihash_kv_48_8_t *) s0,
+				    0 /* is_add */ ) < 0)
+	clib_warning ("session %d not found in hash?",
+		      s0 - cmp->sessions[my_thread_index]);
+
+      ct6_lru_remove (cmp, s0);
+      *recyclep += 1;
+    }
+  else
+    {
+    alloc0:
+      /* Allocate a fresh session */
+      pool_get (cmp->sessions[my_thread_index], s0);
+      *createp += 1;
+    }
+
+  /* Sesison setup */
+  memset (s0, 0, sizeof (*s0));
+  clib_memcpy_fast (s0, kvpp, sizeof (ct6_session_key_t));
+  s0->thread_index = my_thread_index;
+  s0->expires = now + cmp->session_timeout_interval;
+  kvpp->value = s0 - cmp->sessions[my_thread_index];
+  clib_bihash_add_del_48_8 (&cmp->session_hash, kvpp, 1 /* is_add */ );
+  ct6_lru_add (cmp, s0, now);
+  return s0;
+}
+#endif /* CLIB_MARCH_VARIANT */
+
+always_inline uword
+ct6_in2out_inline (vlib_main_t * vm,
+		   vlib_node_runtime_t * node, vlib_frame_t * frame,
+		   int is_trace)
+{
+  u32 n_left_from, *from;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  u16 nexts[VLIB_FRAME_SIZE], *next;
+  ct6_main_t *cmp = &ct6_main;
+  u32 my_thread_index = vm->thread_index;
+  f64 now = vlib_time_now (vm);
+  u32 created = 0;
+  u32 recycled = 0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  vlib_get_buffers (vm, from, bufs, n_left_from);
+  b = bufs;
+  next = nexts;
+
+#if 0
+  while (n_left_from >= 4)
+    {
+      /* Prefetch next iteration. */
+      if (PREDICT_TRUE (n_left_from >= 8))
+	{
+	  vlib_prefetch_buffer_header (b[4], STORE);
+	  vlib_prefetch_buffer_header (b[5], STORE);
+	  vlib_prefetch_buffer_header (b[6], STORE);
+	  vlib_prefetch_buffer_header (b[7], STORE);
+	  CLIB_PREFETCH (b[4]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  CLIB_PREFETCH (b[5]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  CLIB_PREFETCH (b[6]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  CLIB_PREFETCH (b[7]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	}
+
+      /* $$$$ process 4x pkts right here */
+      next[0] = 0;
+      next[1] = 0;
+      next[2] = 0;
+      next[3] = 0;
+
+      if (is_trace)
+	{
+	  if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ct6_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t));
+	      t->next_index = next[0];
+	      t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	    }
+	  if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ct6_trace_t *t = vlib_add_trace (vm, node, b[1], sizeof (*t));
+	      t->next_index = next[1];
+	      t->sw_if_index = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
+	    }
+	  if (b[2]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ct6_trace_t *t = vlib_add_trace (vm, node, b[2], sizeof (*t));
+	      t->next_index = next[2];
+	      t->sw_if_index = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
+	    }
+	  if (b[3]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ct6_trace_t *t = vlib_add_trace (vm, node, b[3], sizeof (*t));
+	      t->next_index = next[3];
+	      t->sw_if_index = vnet_buffer (b[3])->sw_if_index[VLIB_RX];
+	    }
+	}
+
+      b += 4;
+      next += 4;
+      n_left_from -= 4;
+    }
+#endif
+
+  while (n_left_from > 0)
+    {
+      clib_bihash_kv_48_8_t kvp0;
+      ct6_session_key_t *key0;
+      ct6_session_t *s0;
+      u32 session_index0 = ~0;
+      u32 next0, delta0;
+      ethernet_header_t *e0;
+
+      ip6_header_t *ip0;
+      udp_header_t *udp0;
+
+      /* $$$ Set to 0 for pg testing */
+      if (1)
+	{
+	  vnet_feature_next (&next0, b[0]);
+	  next[0] = next0;
+	}
+      else
+	next[0] = CT6_IN2OUT_NEXT_DROP;
+
+      /*
+       * This is an output feature which runs at the last possible
+       * moment. Assume an ethernet header.
+       */
+
+      e0 = vlib_buffer_get_current (b[0]);
+      delta0 = sizeof (*e0);
+      delta0 += (e0->type == clib_net_to_host_u16 (ETHERNET_TYPE_VLAN))
+	? 4 : 0;
+      delta0 += (e0->type == clib_net_to_host_u16 (ETHERNET_TYPE_DOT1AD))
+	? 8 : 0;
+
+      ip0 = (ip6_header_t *) (vlib_buffer_get_current (b[0]) + delta0);
+
+      /*
+       * Pass non-global unicast traffic
+       */
+      if (PREDICT_FALSE (!ip6_address_is_global_unicast (&ip0->src_address)
+			 ||
+			 !ip6_address_is_global_unicast (&ip0->src_address)))
+	goto trace0;
+      /* Pass non-udp, non-tcp traffic */
+      if (PREDICT_FALSE (ip0->protocol != IP_PROTOCOL_TCP &&
+			 ip0->protocol != IP_PROTOCOL_UDP))
+	goto trace0;
+
+      udp0 = ip6_next_header (ip0);
+
+      /*
+       * See if we know about this flow.
+       * Key set up for the out2in path, the performant case
+       */
+      key0 = (ct6_session_key_t *) & kvp0;
+      clib_memcpy_fast (&key0->src, &ip0->dst_address,
+			sizeof (ip6_address_t));
+      clib_memcpy_fast (&key0->dst, &ip0->src_address,
+			sizeof (ip6_address_t));
+      key0->as_u64[4] = 0;
+      key0->as_u64[5] = 0;
+      key0->sport = udp0->dst_port;
+      key0->dport = udp0->src_port;
+      key0->proto = ip0->protocol;
+
+      /* Need to create a new session? */
+      if (clib_bihash_search_48_8 (&cmp->session_hash, &kvp0, &kvp0) < 0)
+	{
+	  s0 =
+	    ct6_create_or_recycle_session (cmp, &kvp0, now, my_thread_index,
+					   &recycled, &created);
+	  session_index0 = kvp0.value;
+	}
+      else
+	{
+	  s0 = pool_elt_at_index (cmp->sessions[my_thread_index], kvp0.value);
+	  session_index0 = kvp0.value;
+	  ct6_update_session_hit (cmp, s0, now);
+	}
+
+    trace0:
+      if (is_trace)
+	{
+	  if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ct6_in2out_trace_t *t =
+		vlib_add_trace (vm, node, b[0], sizeof (*t));
+	      t->next_index = next[0];
+	      t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	      t->session_index = session_index0;
+	    }
+	}
+
+      b += 1;
+      next += 1;
+      n_left_from -= 1;
+    }
+
+  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
+
+  vlib_node_increment_counter (vm, node->node_index,
+			       CT6_IN2OUT_ERROR_PROCESSED, frame->n_vectors);
+  vlib_node_increment_counter (vm, node->node_index,
+			       CT6_IN2OUT_ERROR_CREATED, created);
+  vlib_node_increment_counter (vm, node->node_index,
+			       CT6_IN2OUT_ERROR_RECYCLED, recycled);
+
+  return frame->n_vectors;
+}
+
+VLIB_NODE_FN (ct6_in2out_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+				vlib_frame_t * frame)
+{
+  if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+    return ct6_in2out_inline (vm, node, frame, 1 /* is_trace */ );
+  else
+    return ct6_in2out_inline (vm, node, frame, 0 /* is_trace */ );
+}
+
+/* *INDENT-OFF* */
+#ifndef CLIB_MARCH_VARIANT
+VLIB_REGISTER_NODE (ct6_in2out_node) =
+{
+  .name = "ct6-in2out",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ct6_in2out_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(ct6_in2out_error_strings),
+  .error_strings = ct6_in2out_error_strings,
+
+  .n_next_nodes = CT6_IN2OUT_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+        [CT6_IN2OUT_NEXT_DROP] = "error-drop",
+  },
+  .unformat_buffer = unformat_ethernet_header,
+};
+#endif /* CLIB_MARCH_VARIANT */
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */