ip: refactor reassembly

this is a preparation step for introducing other reassembly types

Type: refactor

Change-Id: I197e299dbd729b00eead31667913b8ceff915d63
Signed-off-by: Klement Sekera <ksekera@cisco.com>

1 files changed, 1818 insertions, 0 deletions

diff --git a/src/vnet/ip/reass/ip4_full_reass.c b/src/vnet/ip/reass/ip4_full_reass.c
new file mode 100644
index 00000000000..7cf4f43b0a8
--- /dev/null
+++ b/src/vnet/ip/reass/ip4_full_reass.c
@@ -0,0 +1,1818 @@
+/*
+ * Copyright (c) 2017 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 IPv4 Full Reassembly.
+ *
+ * This file contains the source code for IPv4 full reassembly.
+ */
+
+#include <vppinfra/vec.h>
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vppinfra/fifo.h>
+#include <vppinfra/bihash_16_8.h>
+#include <vnet/ip/reass/ip4_full_reass.h>
+#include <stddef.h>
+
+#define MSEC_PER_SEC 1000
+#define IP4_REASS_TIMEOUT_DEFAULT_MS 100
+#define IP4_REASS_EXPIRE_WALK_INTERVAL_DEFAULT_MS 10000	// 10 seconds default
+#define IP4_REASS_MAX_REASSEMBLIES_DEFAULT 1024
+#define IP4_REASS_MAX_REASSEMBLY_LENGTH_DEFAULT 3
+#define IP4_REASS_HT_LOAD_FACTOR (0.75)
+
+#define IP4_REASS_DEBUG_BUFFERS 0
+#if IP4_REASS_DEBUG_BUFFERS
+#define IP4_REASS_DEBUG_BUFFER(bi, what)             \
+  do                                                 \
+    {                                                \
+      u32 _bi = bi;                                  \
+      printf (#what "buffer %u", _bi);               \
+      vlib_buffer_t *_b = vlib_get_buffer (vm, _bi); \
+      while (_b->flags & VLIB_BUFFER_NEXT_PRESENT)   \
+        {                                            \
+          _bi = _b->next_buffer;                     \
+          printf ("[%u]", _bi);                      \
+          _b = vlib_get_buffer (vm, _bi);            \
+        }                                            \
+      printf ("\n");                                 \
+      fflush (stdout);                               \
+    }                                                \
+  while (0)
+#else
+#define IP4_REASS_DEBUG_BUFFER(...)
+#endif
+
+typedef enum
+{
+  IP4_REASS_RC_OK,
+  IP4_REASS_RC_TOO_MANY_FRAGMENTS,
+  IP4_REASS_RC_INTERNAL_ERROR,
+  IP4_REASS_RC_NO_BUF,
+  IP4_REASS_RC_HANDOFF,
+} ip4_full_reass_rc_t;
+
+typedef struct
+{
+  union
+  {
+    struct
+    {
+      u32 xx_id;
+      ip4_address_t src;
+      ip4_address_t dst;
+      u16 frag_id;
+      u8 proto;
+      u8 unused;
+    };
+    u64 as_u64[2];
+  };
+} ip4_full_reass_key_t;
+
+typedef union
+{
+  struct
+  {
+    u32 reass_index;
+    u32 memory_owner_thread_index;
+  };
+  u64 as_u64;
+} ip4_full_reass_val_t;
+
+typedef union
+{
+  struct
+  {
+    ip4_full_reass_key_t k;
+    ip4_full_reass_val_t v;
+  };
+  clib_bihash_kv_16_8_t kv;
+} ip4_full_reass_kv_t;
+
+always_inline u32
+ip4_full_reass_buffer_get_data_offset (vlib_buffer_t * b)
+{
+  vnet_buffer_opaque_t *vnb = vnet_buffer (b);
+  return vnb->ip.reass.range_first - vnb->ip.reass.fragment_first;
+}
+
+always_inline u16
+ip4_full_reass_buffer_get_data_len (vlib_buffer_t * b)
+{
+  vnet_buffer_opaque_t *vnb = vnet_buffer (b);
+  return clib_min (vnb->ip.reass.range_last, vnb->ip.reass.fragment_last) -
+    (vnb->ip.reass.fragment_first +
+     ip4_full_reass_buffer_get_data_offset (b)) + 1;
+}
+
+typedef struct
+{
+  // hash table key
+  ip4_full_reass_key_t key;
+  // time when last packet was received
+  f64 last_heard;
+  // internal id of this reassembly
+  u64 id;
+  // buffer index of first buffer in this reassembly context
+  u32 first_bi;
+  // last octet of packet, ~0 until fragment without more_fragments arrives
+  u32 last_packet_octet;
+  // length of data collected so far
+  u32 data_len;
+  // trace operation counter
+  u32 trace_op_counter;
+  // next index - used by non-feature node
+  u32 next_index;
+  // error next index - used by custom apps (~0 if not used)
+  u32 error_next_index;
+  // minimum fragment length for this reassembly - used to estimate MTU
+  u16 min_fragment_length;
+  // number of fragments in this reassembly
+  u32 fragments_n;
+  // thread owning memory for this context (whose pool contains this ctx)
+  u32 memory_owner_thread_index;
+  // thread which received fragment with offset 0 and which sends out the
+  // completed reassembly
+  u32 sendout_thread_index;
+} ip4_full_reass_t;
+
+typedef struct
+{
+  ip4_full_reass_t *pool;
+  u32 reass_n;
+  u32 id_counter;
+  clib_spinlock_t lock;
+} ip4_full_reass_per_thread_t;
+
+typedef struct
+{
+  // IPv4 config
+  u32 timeout_ms;
+  f64 timeout;
+  u32 expire_walk_interval_ms;
+  // maximum number of fragments in one reassembly
+  u32 max_reass_len;
+  // maximum number of reassemblies
+  u32 max_reass_n;
+
+  // IPv4 runtime
+  clib_bihash_16_8_t hash;
+  // per-thread data
+  ip4_full_reass_per_thread_t *per_thread_data;
+
+  // convenience
+  vlib_main_t *vlib_main;
+
+  // node index of ip4-drop node
+  u32 ip4_drop_idx;
+  u32 ip4_full_reass_expire_node_idx;
+
+  /** Worker handoff */
+  u32 fq_index;
+  u32 fq_feature_index;
+
+} ip4_full_reass_main_t;
+
+extern ip4_full_reass_main_t ip4_full_reass_main;
+
+#ifndef CLIB_MARCH_VARIANT
+ip4_full_reass_main_t ip4_full_reass_main;
+#endif /* CLIB_MARCH_VARIANT */
+
+typedef enum
+{
+  IP4_FULL_REASS_NEXT_INPUT,
+  IP4_FULL_REASS_NEXT_DROP,
+  IP4_FULL_REASS_NEXT_HANDOFF,
+  IP4_FULL_REASS_N_NEXT,
+} ip4_full_reass_next_t;
+
+typedef enum
+{
+  RANGE_NEW,
+  RANGE_SHRINK,
+  RANGE_DISCARD,
+  RANGE_OVERLAP,
+  FINALIZE,
+  HANDOFF,
+} ip4_full_reass_trace_operation_e;
+
+typedef struct
+{
+  u16 range_first;
+  u16 range_last;
+  u32 range_bi;
+  i32 data_offset;
+  u32 data_len;
+  u32 first_bi;
+} ip4_full_reass_range_trace_t;
+
+typedef struct
+{
+  ip4_full_reass_trace_operation_e action;
+  u32 reass_id;
+  ip4_full_reass_range_trace_t trace_range;
+  u32 size_diff;
+  u32 op_id;
+  u32 thread_id;
+  u32 thread_id_to;
+  u32 fragment_first;
+  u32 fragment_last;
+  u32 total_data_len;
+} ip4_full_reass_trace_t;
+
+extern vlib_node_registration_t ip4_full_reass_node;
+extern vlib_node_registration_t ip4_full_reass_node_feature;
+
+static void
+ip4_full_reass_trace_details (vlib_main_t * vm, u32 bi,
+			      ip4_full_reass_range_trace_t * trace)
+{
+  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+  vnet_buffer_opaque_t *vnb = vnet_buffer (b);
+  trace->range_first = vnb->ip.reass.range_first;
+  trace->range_last = vnb->ip.reass.range_last;
+  trace->data_offset = ip4_full_reass_buffer_get_data_offset (b);
+  trace->data_len = ip4_full_reass_buffer_get_data_len (b);
+  trace->range_bi = bi;
+}
+
+static u8 *
+format_ip4_full_reass_range_trace (u8 * s, va_list * args)
+{
+  ip4_full_reass_range_trace_t *trace =
+    va_arg (*args, ip4_full_reass_range_trace_t *);
+  s =
+    format (s, "range: [%u, %u], off %d, len %u, bi %u", trace->range_first,
+	    trace->range_last, trace->data_offset, trace->data_len,
+	    trace->range_bi);
+  return s;
+}
+
+static u8 *
+format_ip4_full_reass_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 *);
+  ip4_full_reass_trace_t *t = va_arg (*args, ip4_full_reass_trace_t *);
+  u32 indent = 0;
+  if (~0 != t->reass_id)
+    {
+      s = format (s, "reass id: %u, op id: %u, ", t->reass_id, t->op_id);
+      indent = format_get_indent (s);
+      s =
+	format (s,
+		"first bi: %u, data len: %u, ip/fragment[%u, %u]",
+		t->trace_range.first_bi, t->total_data_len, t->fragment_first,
+		t->fragment_last);
+    }
+  switch (t->action)
+    {
+    case RANGE_SHRINK:
+      s = format (s, "\n%Ushrink %U by %u", format_white_space, indent,
+		  format_ip4_full_reass_range_trace, &t->trace_range,
+		  t->size_diff);
+      break;
+    case RANGE_DISCARD:
+      s = format (s, "\n%Udiscard %U", format_white_space, indent,
+		  format_ip4_full_reass_range_trace, &t->trace_range);
+      break;
+    case RANGE_NEW:
+      s = format (s, "\n%Unew %U", format_white_space, indent,
+		  format_ip4_full_reass_range_trace, &t->trace_range);
+      break;
+    case RANGE_OVERLAP:
+      s = format (s, "\n%Uoverlapping/ignored %U", format_white_space, indent,
+		  format_ip4_full_reass_range_trace, &t->trace_range);
+      break;
+    case FINALIZE:
+      s = format (s, "\n%Ufinalize reassembly", format_white_space, indent);
+      break;
+    case HANDOFF:
+      s =
+	format (s, "handoff from thread #%u to thread #%u", t->thread_id,
+		t->thread_id_to);
+      break;
+    }
+  return s;
+}
+
+static void
+ip4_full_reass_add_trace (vlib_main_t * vm, vlib_node_runtime_t * node,
+			  ip4_full_reass_main_t * rm,
+			  ip4_full_reass_t * reass, u32 bi,
+			  ip4_full_reass_trace_operation_e action,
+			  u32 size_diff, u32 thread_id_to)
+{
+  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+  vnet_buffer_opaque_t *vnb = vnet_buffer (b);
+  ip4_full_reass_trace_t *t = vlib_add_trace (vm, node, b, sizeof (t[0]));
+  if (reass)
+    {
+      t->reass_id = reass->id;
+      t->op_id = reass->trace_op_counter;
+      t->trace_range.first_bi = reass->first_bi;
+      t->total_data_len = reass->data_len;
+      ++reass->trace_op_counter;
+    }
+  else
+    {
+      t->reass_id = ~0;
+      t->op_id = 0;
+      t->trace_range.first_bi = 0;
+      t->total_data_len = 0;
+    }
+  t->action = action;
+  ip4_full_reass_trace_details (vm, bi, &t->trace_range);
+  t->size_diff = size_diff;
+  t->thread_id = vm->thread_index;
+  t->thread_id_to = thread_id_to;
+  t->fragment_first = vnb->ip.reass.fragment_first;
+  t->fragment_last = vnb->ip.reass.fragment_last;
+#if 0
+  static u8 *s = NULL;
+  s = format (s, "%U", format_ip4_full_reass_trace, NULL, NULL, t);
+  printf ("%.*s\n", vec_len (s), s);
+  fflush (stdout);
+  vec_reset_length (s);
+#endif
+}
+
+always_inline void
+ip4_full_reass_free_ctx (ip4_full_reass_per_thread_t * rt,
+			 ip4_full_reass_t * reass)
+{
+  pool_put (rt->pool, reass);
+  --rt->reass_n;
+}
+
+always_inline void
+ip4_full_reass_free (ip4_full_reass_main_t * rm,
+		     ip4_full_reass_per_thread_t * rt,
+		     ip4_full_reass_t * reass)
+{
+  clib_bihash_kv_16_8_t kv;
+  kv.key[0] = reass->key.as_u64[0];
+  kv.key[1] = reass->key.as_u64[1];
+  clib_bihash_add_del_16_8 (&rm->hash, &kv, 0);
+  return ip4_full_reass_free_ctx (rt, reass);
+}
+
+always_inline void
+ip4_full_reass_drop_all (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 ip4_full_reass_main_t * rm, ip4_full_reass_t * reass)
+{
+  u32 range_bi = reass->first_bi;
+  vlib_buffer_t *range_b;
+  vnet_buffer_opaque_t *range_vnb;
+  u32 *to_free = NULL;
+  while (~0 != range_bi)
+    {
+      range_b = vlib_get_buffer (vm, range_bi);
+      range_vnb = vnet_buffer (range_b);
+      u32 bi = range_bi;
+      while (~0 != bi)
+	{
+	  vec_add1 (to_free, bi);
+	  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+	  if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+	    {
+	      bi = b->next_buffer;
+	      b->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
+	    }
+	  else
+	    {
+	      bi = ~0;
+	    }
+	}
+      range_bi = range_vnb->ip.reass.next_range_bi;
+    }
+  /* send to next_error_index */
+  if (~0 != reass->error_next_index)
+    {
+      u32 n_left_to_next, *to_next, next_index;
+
+      next_index = reass->error_next_index;
+      u32 bi = ~0;
+
+      while (vec_len (to_free) > 0)
+	{
+	  vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+	  while (vec_len (to_free) > 0 && n_left_to_next > 0)
+	    {
+	      bi = vec_pop (to_free);
+
+	      if (~0 != bi)
+		{
+		  to_next[0] = bi;
+		  to_next += 1;
+		  n_left_to_next -= 1;
+		}
+	    }
+	  vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+	}
+    }
+  else
+    {
+      vlib_buffer_free (vm, to_free, vec_len (to_free));
+    }
+}
+
+always_inline void
+ip4_full_reass_init (ip4_full_reass_t * reass)
+{
+  reass->first_bi = ~0;
+  reass->last_packet_octet = ~0;
+  reass->data_len = 0;
+  reass->next_index = ~0;
+  reass->error_next_index = ~0;
+}
+
+always_inline ip4_full_reass_t *
+ip4_full_reass_find_or_create (vlib_main_t * vm, vlib_node_runtime_t * node,
+			       ip4_full_reass_main_t * rm,
+			       ip4_full_reass_per_thread_t * rt,
+			       ip4_full_reass_kv_t * kv, u8 * do_handoff)
+{
+  ip4_full_reass_t *reass;
+  f64 now;
+
+again:
+
+  reass = NULL;
+  now = vlib_time_now (vm);
+  if (!clib_bihash_search_16_8
+      (&rm->hash, (clib_bihash_kv_16_8_t *) kv, (clib_bihash_kv_16_8_t *) kv))
+    {
+      reass =
+	pool_elt_at_index (rm->per_thread_data
+			   [kv->v.memory_owner_thread_index].pool,
+			   kv->v.reass_index);
+      if (vm->thread_index != reass->memory_owner_thread_index)
+	{
+	  *do_handoff = 1;
+	  return reass;
+	}
+
+      if (now > reass->last_heard + rm->timeout)
+	{
+	  ip4_full_reass_drop_all (vm, node, rm, reass);
+	  ip4_full_reass_free (rm, rt, reass);
+	  reass = NULL;
+	}
+    }
+
+  if (reass)
+    {
+      reass->last_heard = now;
+      return reass;
+    }
+
+  if (rt->reass_n >= rm->max_reass_n)
+    {
+      reass = NULL;
+      return reass;
+    }
+  else
+    {
+      pool_get (rt->pool, reass);
+      clib_memset (reass, 0, sizeof (*reass));
+      reass->id = ((u64) vm->thread_index * 1000000000) + rt->id_counter;
+      reass->memory_owner_thread_index = vm->thread_index;
+      ++rt->id_counter;
+      ip4_full_reass_init (reass);
+      ++rt->reass_n;
+    }
+
+  reass->key.as_u64[0] = ((clib_bihash_kv_16_8_t *) kv)->key[0];
+  reass->key.as_u64[1] = ((clib_bihash_kv_16_8_t *) kv)->key[1];
+  kv->v.reass_index = (reass - rt->pool);
+  kv->v.memory_owner_thread_index = vm->thread_index;
+  reass->last_heard = now;
+
+  int rv =
+    clib_bihash_add_del_16_8 (&rm->hash, (clib_bihash_kv_16_8_t *) kv, 2);
+  if (rv)
+    {
+      ip4_full_reass_free_ctx (rt, reass);
+      reass = NULL;
+      // if other worker created a context already work with the other copy
+      if (-2 == rv)
+	goto again;
+    }
+
+  return reass;
+}
+
+always_inline ip4_full_reass_rc_t
+ip4_full_reass_finalize (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 ip4_full_reass_main_t * rm,
+			 ip4_full_reass_per_thread_t * rt,
+			 ip4_full_reass_t * reass, u32 * bi0,
+			 u32 * next0, u32 * error0, bool is_custom_app)
+{
+  vlib_buffer_t *first_b = vlib_get_buffer (vm, reass->first_bi);
+  vlib_buffer_t *last_b = NULL;
+  u32 sub_chain_bi = reass->first_bi;
+  u32 total_length = 0;
+  u32 buf_cnt = 0;
+  do
+    {
+      u32 tmp_bi = sub_chain_bi;
+      vlib_buffer_t *tmp = vlib_get_buffer (vm, tmp_bi);
+      ip4_header_t *ip = vlib_buffer_get_current (tmp);
+      vnet_buffer_opaque_t *vnb = vnet_buffer (tmp);
+      if (!(vnb->ip.reass.range_first >= vnb->ip.reass.fragment_first) &&
+	  !(vnb->ip.reass.range_last > vnb->ip.reass.fragment_first))
+	{
+	  return IP4_REASS_RC_INTERNAL_ERROR;
+	}
+
+      u32 data_len = ip4_full_reass_buffer_get_data_len (tmp);
+      u32 trim_front =
+	ip4_header_bytes (ip) + ip4_full_reass_buffer_get_data_offset (tmp);
+      u32 trim_end =
+	vlib_buffer_length_in_chain (vm, tmp) - trim_front - data_len;
+      if (tmp_bi == reass->first_bi)
+	{
+	  /* first buffer - keep ip4 header */
+	  if (0 != ip4_full_reass_buffer_get_data_offset (tmp))
+	    {
+	      return IP4_REASS_RC_INTERNAL_ERROR;
+	    }
+	  trim_front = 0;
+	  trim_end = vlib_buffer_length_in_chain (vm, tmp) - data_len -
+	    ip4_header_bytes (ip);
+	  if (!(vlib_buffer_length_in_chain (vm, tmp) - trim_end > 0))
+	    {
+	      return IP4_REASS_RC_INTERNAL_ERROR;
+	    }
+	}
+      u32 keep_data =
+	vlib_buffer_length_in_chain (vm, tmp) - trim_front - trim_end;
+      while (1)
+	{
+	  ++buf_cnt;
+	  if (trim_front)
+	    {
+	      if (trim_front > tmp->current_length)
+		{
+		  /* drop whole buffer */
+		  u32 to_be_freed_bi = tmp_bi;
+		  trim_front -= tmp->current_length;
+		  if (!(tmp->flags & VLIB_BUFFER_NEXT_PRESENT))
+		    {
+		      return IP4_REASS_RC_INTERNAL_ERROR;
+		    }
+		  tmp->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
+		  tmp_bi = tmp->next_buffer;
+		  tmp->next_buffer = 0;
+		  tmp = vlib_get_buffer (vm, tmp_bi);
+		  vlib_buffer_free_one (vm, to_be_freed_bi);
+		  continue;
+		}
+	      else
+		{
+		  vlib_buffer_advance (tmp, trim_front);
+		  trim_front = 0;
+		}
+	    }
+	  if (keep_data)
+	    {
+	      if (last_b)
+		{
+		  last_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
+		  last_b->next_buffer = tmp_bi;
+		}
+	      last_b = tmp;
+	      if (keep_data <= tmp->current_length)
+		{
+		  tmp->current_length = keep_data;
+		  keep_data = 0;
+		}
+	      else
+		{
+		  keep_data -= tmp->current_length;
+		  if (!(tmp->flags & VLIB_BUFFER_NEXT_PRESENT))
+		    {
+		      return IP4_REASS_RC_INTERNAL_ERROR;
+		    }
+		}
+	      total_length += tmp->current_length;
+	      if (tmp->flags & VLIB_BUFFER_NEXT_PRESENT)
+		{
+		  tmp_bi = tmp->next_buffer;
+		  tmp = vlib_get_buffer (vm, tmp->next_buffer);
+		}
+	      else
+		{
+		  break;
+		}
+	    }
+	  else
+	    {
+	      u32 to_be_freed_bi = tmp_bi;
+	      if (reass->first_bi == tmp_bi)
+		{
+		  return IP4_REASS_RC_INTERNAL_ERROR;
+		}
+	      if (tmp->flags & VLIB_BUFFER_NEXT_PRESENT)
+		{
+		  tmp->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
+		  tmp_bi = tmp->next_buffer;
+		  tmp->next_buffer = 0;
+		  tmp = vlib_get_buffer (vm, tmp_bi);
+		  vlib_buffer_free_one (vm, to_be_freed_bi);
+		}
+	      else
+		{
+		  tmp->next_buffer = 0;
+		  vlib_buffer_free_one (vm, to_be_freed_bi);
+		  break;
+		}
+	    }
+	}
+      sub_chain_bi =
+	vnet_buffer (vlib_get_buffer (vm, sub_chain_bi))->ip.
+	reass.next_range_bi;
+    }
+  while (~0 != sub_chain_bi);
+
+  if (!last_b)
+    {
+      return IP4_REASS_RC_INTERNAL_ERROR;
+    }
+  last_b->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
+
+  if (total_length < first_b->current_length)
+    {
+      return IP4_REASS_RC_INTERNAL_ERROR;
+    }
+  total_length -= first_b->current_length;
+  first_b->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
+  first_b->total_length_not_including_first_buffer = total_length;
+  ip4_header_t *ip = vlib_buffer_get_current (first_b);
+  ip->flags_and_fragment_offset = 0;
+  ip->length = clib_host_to_net_u16 (first_b->current_length + total_length);
+  ip->checksum = ip4_header_checksum (ip);
+  if (!vlib_buffer_chain_linearize (vm, first_b))
+    {
+      return IP4_REASS_RC_NO_BUF;
+    }
+  // reset to reconstruct the mbuf linking
+  first_b->flags &= ~VLIB_BUFFER_EXT_HDR_VALID;
+  if (PREDICT_FALSE (first_b->flags & VLIB_BUFFER_IS_TRACED))
+    {
+      ip4_full_reass_add_trace (vm, node, rm, reass, reass->first_bi,
+				FINALIZE, 0, ~0);
+#if 0
+      // following code does a hexdump of packet fragments to stdout ...
+      do
+	{
+	  u32 bi = reass->first_bi;
+	  u8 *s = NULL;
+	  while (~0 != bi)
+	    {
+	      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+	      s = format (s, "%u: %U\n", bi, format_hexdump,
+			  vlib_buffer_get_current (b), b->current_length);
+	      if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+		{
+		  bi = b->next_buffer;
+		}
+	      else
+		{
+		  break;
+		}
+	    }
+	  printf ("%.*s\n", vec_len (s), s);
+	  fflush (stdout);
+	  vec_free (s);
+	}
+      while (0);
+#endif
+    }
+  *bi0 = reass->first_bi;
+  if (!is_custom_app)
+    {
+      *next0 = IP4_FULL_REASS_NEXT_INPUT;
+    }
+  else
+    {
+      *next0 = reass->next_index;
+    }
+  vnet_buffer (first_b)->ip.reass.estimated_mtu = reass->min_fragment_length;
+  *error0 = IP4_ERROR_NONE;
+  ip4_full_reass_free (rm, rt, reass);
+  reass = NULL;
+  return IP4_REASS_RC_OK;
+}
+
+always_inline ip4_full_reass_rc_t
+ip4_full_reass_insert_range_in_chain (vlib_main_t * vm,
+				      ip4_full_reass_main_t * rm,
+				      ip4_full_reass_per_thread_t * rt,
+				      ip4_full_reass_t * reass,
+				      u32 prev_range_bi, u32 new_next_bi)
+{
+  vlib_buffer_t *new_next_b = vlib_get_buffer (vm, new_next_bi);
+  vnet_buffer_opaque_t *new_next_vnb = vnet_buffer (new_next_b);
+  if (~0 != prev_range_bi)
+    {
+      vlib_buffer_t *prev_b = vlib_get_buffer (vm, prev_range_bi);
+      vnet_buffer_opaque_t *prev_vnb = vnet_buffer (prev_b);
+      new_next_vnb->ip.reass.next_range_bi = prev_vnb->ip.reass.next_range_bi;
+      prev_vnb->ip.reass.next_range_bi = new_next_bi;
+    }
+  else
+    {
+      if (~0 != reass->first_bi)
+	{
+	  new_next_vnb->ip.reass.next_range_bi = reass->first_bi;
+	}
+      reass->first_bi = new_next_bi;
+    }
+  vnet_buffer_opaque_t *vnb = vnet_buffer (new_next_b);
+  if (!(vnb->ip.reass.range_first >= vnb->ip.reass.fragment_first) &&
+      !(vnb->ip.reass.range_last > vnb->ip.reass.fragment_first))
+    {
+      return IP4_REASS_RC_INTERNAL_ERROR;
+    }
+  reass->data_len += ip4_full_reass_buffer_get_data_len (new_next_b);
+  return IP4_REASS_RC_OK;
+}
+
+always_inline ip4_full_reass_rc_t
+ip4_full_reass_remove_range_from_chain (vlib_main_t * vm,
+					vlib_node_runtime_t * node,
+					ip4_full_reass_main_t * rm,
+					ip4_full_reass_t * reass,
+					u32 prev_range_bi, u32 discard_bi)
+{
+  vlib_buffer_t *discard_b = vlib_get_buffer (vm, discard_bi);
+  vnet_buffer_opaque_t *discard_vnb = vnet_buffer (discard_b);
+  if (~0 != prev_range_bi)
+    {
+      vlib_buffer_t *prev_b = vlib_get_buffer (vm, prev_range_bi);
+      vnet_buffer_opaque_t *prev_vnb = vnet_buffer (prev_b);
+      if (!(prev_vnb->ip.reass.next_range_bi == discard_bi))
+	{
+	  return IP4_REASS_RC_INTERNAL_ERROR;
+	}
+      prev_vnb->ip.reass.next_range_bi = discard_vnb->ip.reass.next_range_bi;
+    }
+  else
+    {
+      reass->first_bi = discard_vnb->ip.reass.next_range_bi;
+    }
+  vnet_buffer_opaque_t *vnb = vnet_buffer (discard_b);
+  if (!(vnb->ip.reass.range_first >= vnb->ip.reass.fragment_first) &&
+      !(vnb->ip.reass.range_last > vnb->ip.reass.fragment_first))
+    {
+      return IP4_REASS_RC_INTERNAL_ERROR;
+    }
+  reass->data_len -= ip4_full_reass_buffer_get_data_len (discard_b);
+  while (1)
+    {
+      u32 to_be_freed_bi = discard_bi;
+      if (PREDICT_FALSE (discard_b->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  ip4_full_reass_add_trace (vm, node, rm, reass, discard_bi,
+				    RANGE_DISCARD, 0, ~0);
+	}
+      if (discard_b->flags & VLIB_BUFFER_NEXT_PRESENT)
+	{
+	  discard_b->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
+	  discard_bi = discard_b->next_buffer;
+	  discard_b->next_buffer = 0;
+	  discard_b = vlib_get_buffer (vm, discard_bi);
+	  vlib_buffer_free_one (vm, to_be_freed_bi);
+	}
+      else
+	{
+	  discard_b->next_buffer = 0;
+	  vlib_buffer_free_one (vm, to_be_freed_bi);
+	  break;
+	}
+    }
+  return IP4_REASS_RC_OK;
+}
+
+always_inline ip4_full_reass_rc_t
+ip4_full_reass_update (vlib_main_t * vm, vlib_node_runtime_t * node,
+		       ip4_full_reass_main_t * rm,
+		       ip4_full_reass_per_thread_t * rt,
+		       ip4_full_reass_t * reass, u32 * bi0, u32 * next0,
+		       u32 * error0, bool is_custom_app,
+		       u32 * handoff_thread_idx)
+{
+  vlib_buffer_t *fb = vlib_get_buffer (vm, *bi0);
+  vnet_buffer_opaque_t *fvnb = vnet_buffer (fb);
+  if (is_custom_app)
+    {
+      // store (error_)next_index before it's overwritten
+      reass->next_index = fvnb->ip.reass.next_index;
+      reass->error_next_index = fvnb->ip.reass.error_next_index;
+    }
+  ip4_full_reass_rc_t rc = IP4_REASS_RC_OK;
+  int consumed = 0;
+  ip4_header_t *fip = vlib_buffer_get_current (fb);
+  const u32 fragment_first = ip4_get_fragment_offset_bytes (fip);
+  const u32 fragment_length =
+    clib_net_to_host_u16 (fip->length) - ip4_header_bytes (fip);
+  const u32 fragment_last = fragment_first + fragment_length - 1;
+  fvnb->ip.reass.fragment_first = fragment_first;
+  fvnb->ip.reass.fragment_last = fragment_last;
+  int more_fragments = ip4_get_fragment_more (fip);
+  u32 candidate_range_bi = reass->first_bi;
+  u32 prev_range_bi = ~0;
+  fvnb->ip.reass.range_first = fragment_first;
+  fvnb->ip.reass.range_last = fragment_last;
+  fvnb->ip.reass.next_range_bi = ~0;
+  if (!more_fragments)
+    {
+      reass->last_packet_octet = fragment_last;
+    }
+  if (~0 == reass->first_bi)
+    {
+      // starting a new reassembly
+      rc =
+	ip4_full_reass_insert_range_in_chain (vm, rm, rt, reass,
+					      prev_range_bi, *bi0);
+      if (IP4_REASS_RC_OK != rc)
+	{
+	  return rc;
+	}
+      if (PREDICT_FALSE (fb->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  ip4_full_reass_add_trace (vm, node, rm, reass, *bi0, RANGE_NEW, 0,
+				    ~0);
+	}
+      *bi0 = ~0;
+      reass->min_fragment_length = clib_net_to_host_u16 (fip->length);
+      reass->fragments_n = 1;
+      return IP4_REASS_RC_OK;
+    }
+  reass->min_fragment_length =
+    clib_min (clib_net_to_host_u16 (fip->length),
+	      fvnb->ip.reass.estimated_mtu);
+  while (~0 != candidate_range_bi)
+    {
+      vlib_buffer_t *candidate_b = vlib_get_buffer (vm, candidate_range_bi);
+      vnet_buffer_opaque_t *candidate_vnb = vnet_buffer (candidate_b);
+      if (fragment_first > candidate_vnb->ip.reass.range_last)
+	{
+	  // this fragments starts after candidate range
+	  prev_range_bi = candidate_range_bi;
+	  candidate_range_bi = candidate_vnb->ip.reass.next_range_bi;
+	  if (candidate_vnb->ip.reass.range_last < fragment_last &&
+	      ~0 == candidate_range_bi)
+	    {
+	      // special case - this fragment falls beyond all known ranges
+	      rc =
+		ip4_full_reass_insert_range_in_chain (vm, rm, rt, reass,
+						      prev_range_bi, *bi0);
+	      if (IP4_REASS_RC_OK != rc)
+		{
+		  return rc;
+		}
+	      consumed = 1;
+	      break;
+	    }
+	  continue;
+	}
+      if (fragment_last < candidate_vnb->ip.reass.range_first)
+	{
+	  // this fragment ends before candidate range without any overlap
+	  rc =
+	    ip4_full_reass_insert_range_in_chain (vm, rm, rt, reass,
+						  prev_range_bi, *bi0);
+	  if (IP4_REASS_RC_OK != rc)
+	    {
+	      return rc;
+	    }
+	  consumed = 1;
+	}
+      else
+	{
+	  if (fragment_first >= candidate_vnb->ip.reass.range_first &&
+	      fragment_last <= candidate_vnb->ip.reass.range_last)
+	    {
+	      // this fragment is a (sub)part of existing range, ignore it
+	      if (PREDICT_FALSE (fb->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  ip4_full_reass_add_trace (vm, node, rm, reass, *bi0,
+					    RANGE_OVERLAP, 0, ~0);
+		}
+	      break;
+	    }
+	  int discard_candidate = 0;
+	  if (fragment_first < candidate_vnb->ip.reass.range_first)
+	    {
+	      u32 overlap =
+		fragment_last - candidate_vnb->ip.reass.range_first + 1;
+	      if (overlap < ip4_full_reass_buffer_get_data_len (candidate_b))
+		{
+		  candidate_vnb->ip.reass.range_first += overlap;
+		  if (reass->data_len < overlap)
+		    {
+		      return IP4_REASS_RC_INTERNAL_ERROR;
+		    }
+		  reass->data_len -= overlap;
+		  if (PREDICT_FALSE (fb->flags & VLIB_BUFFER_IS_TRACED))
+		    {
+		      ip4_full_reass_add_trace (vm, node, rm, reass,
+						candidate_range_bi,
+						RANGE_SHRINK, 0, ~0);
+		    }
+		  rc =
+		    ip4_full_reass_insert_range_in_chain (vm, rm, rt, reass,
+							  prev_range_bi,
+							  *bi0);
+		  if (IP4_REASS_RC_OK != rc)
+		    {
+		      return rc;
+		    }
+		  consumed = 1;
+		}
+	      else
+		{
+		  discard_candidate = 1;
+		}
+	    }
+	  else if (fragment_last > candidate_vnb->ip.reass.range_last)
+	    {
+	      u32 overlap =
+		candidate_vnb->ip.reass.range_last - fragment_first + 1;
+	      if (overlap < ip4_full_reass_buffer_get_data_len (candidate_b))
+		{
+		  fvnb->ip.reass.range_first += overlap;
+		  if (~0 != candidate_vnb->ip.reass.next_range_bi)
+		    {
+		      prev_range_bi = candidate_range_bi;
+		      candidate_range_bi =
+			candidate_vnb->ip.reass.next_range_bi;
+		      continue;
+		    }
+		  else
+		    {
+		      // special case - last range discarded
+		      rc =
+			ip4_full_reass_insert_range_in_chain (vm, rm, rt,
+							      reass,
+							      candidate_range_bi,
+							      *bi0);
+		      if (IP4_REASS_RC_OK != rc)
+			{
+			  return rc;
+			}
+		      consumed = 1;
+		    }
+		}
+	      else
+		{
+		  discard_candidate = 1;
+		}
+	    }
+	  else
+	    {
+	      discard_candidate = 1;
+	    }
+	  if (discard_candidate)
+	    {
+	      u32 next_range_bi = candidate_vnb->ip.reass.next_range_bi;
+	      // discard candidate range, probe next range
+	      rc =
+		ip4_full_reass_remove_range_from_chain (vm, node, rm, reass,
+							prev_range_bi,
+							candidate_range_bi);
+	      if (IP4_REASS_RC_OK != rc)
+		{
+		  return rc;
+		}
+	      if (~0 != next_range_bi)
+		{
+		  candidate_range_bi = next_range_bi;
+		  continue;
+		}
+	      else
+		{
+		  // special case - last range discarded
+		  rc =
+		    ip4_full_reass_insert_range_in_chain (vm, rm, rt, reass,
+							  prev_range_bi,
+							  *bi0);
+		  if (IP4_REASS_RC_OK != rc)
+		    {
+		      return rc;
+		    }
+		  consumed = 1;
+		}
+	    }
+	}
+      break;
+    }
+  ++reass->fragments_n;
+  if (consumed)
+    {
+      if (PREDICT_FALSE (fb->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  ip4_full_reass_add_trace (vm, node, rm, reass, *bi0, RANGE_NEW, 0,
+				    ~0);
+	}
+    }
+  if (~0 != reass->last_packet_octet &&
+      reass->data_len == reass->last_packet_octet + 1)
+    {
+      *handoff_thread_idx = reass->sendout_thread_index;
+      rc =
+	ip4_full_reass_finalize (vm, node, rm, rt, reass, bi0, next0, error0,
+				 is_custom_app);
+      if (IP4_REASS_RC_OK == rc
+	  && reass->memory_owner_thread_index != reass->sendout_thread_index)
+	{
+	  rc = IP4_REASS_RC_HANDOFF;
+	}
+    }
+  else
+    {
+      if (consumed)
+	{
+	  *bi0 = ~0;
+	  if (reass->fragments_n > rm->max_reass_len)
+	    {
+	      rc = IP4_REASS_RC_TOO_MANY_FRAGMENTS;
+	    }
+	}
+      else
+	{
+	  *next0 = IP4_FULL_REASS_NEXT_DROP;
+	  *error0 = IP4_ERROR_REASS_DUPLICATE_FRAGMENT;
+	}
+    }
+  return rc;
+}
+
+always_inline uword
+ip4_full_reass_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+		       vlib_frame_t * frame, bool is_feature,
+		       bool is_custom_app)
+{
+  u32 *from = vlib_frame_vector_args (frame);
+  u32 n_left_from, n_left_to_next, *to_next, next_index;
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+  ip4_full_reass_per_thread_t *rt = &rm->per_thread_data[vm->thread_index];
+  clib_spinlock_lock (&rt->lock);
+
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  u32 error0 = IP4_ERROR_NONE;
+
+	  bi0 = from[0];
+	  b0 = vlib_get_buffer (vm, bi0);
+
+	  ip4_header_t *ip0 = vlib_buffer_get_current (b0);
+	  if (!ip4_get_fragment_more (ip0) && !ip4_get_fragment_offset (ip0))
+	    {
+	      // this is a whole packet - no fragmentation
+	      if (!is_custom_app)
+		{
+		  next0 = IP4_FULL_REASS_NEXT_INPUT;
+		}
+	      else
+		{
+		  next0 = vnet_buffer (b0)->ip.reass.next_index;
+		}
+	      goto packet_enqueue;
+	    }
+	  const u32 fragment_first = ip4_get_fragment_offset_bytes (ip0);
+	  const u32 fragment_length =
+	    clib_net_to_host_u16 (ip0->length) - ip4_header_bytes (ip0);
+	  const u32 fragment_last = fragment_first + fragment_length - 1;
+	  if (fragment_first > fragment_last || fragment_first + fragment_length > UINT16_MAX - 20 || (fragment_length < 8 && ip4_get_fragment_more (ip0)))	// 8 is minimum frag length per RFC 791
+	    {
+	      next0 = IP4_FULL_REASS_NEXT_DROP;
+	      error0 = IP4_ERROR_REASS_MALFORMED_PACKET;
+	      goto packet_enqueue;
+	    }
+	  ip4_full_reass_kv_t kv;
+	  u8 do_handoff = 0;
+
+	  kv.k.as_u64[0] =
+	    (u64) vec_elt (ip4_main.fib_index_by_sw_if_index,
+			   vnet_buffer (b0)->sw_if_index[VLIB_RX]) |
+	    (u64) ip0->src_address.as_u32 << 32;
+	  kv.k.as_u64[1] =
+	    (u64) ip0->dst_address.
+	    as_u32 | (u64) ip0->fragment_id << 32 | (u64) ip0->protocol << 48;
+
+	  ip4_full_reass_t *reass =
+	    ip4_full_reass_find_or_create (vm, node, rm, rt, &kv,
+					   &do_handoff);
+
+	  if (reass)
+	    {
+	      const u32 fragment_first = ip4_get_fragment_offset_bytes (ip0);
+	      if (0 == fragment_first)
+		{
+		  reass->sendout_thread_index = vm->thread_index;
+		}
+	    }
+
+	  if (PREDICT_FALSE (do_handoff))
+	    {
+	      next0 = IP4_FULL_REASS_NEXT_HANDOFF;
+	      if (is_feature)
+		vnet_buffer (b0)->ip.reass.owner_feature_thread_index =
+		  kv.v.memory_owner_thread_index;
+	      else
+		vnet_buffer (b0)->ip.reass.owner_thread_index =
+		  kv.v.memory_owner_thread_index;
+	    }
+	  else if (reass)
+	    {
+	      u32 handoff_thread_idx;
+	      switch (ip4_full_reass_update
+		      (vm, node, rm, rt, reass, &bi0, &next0,
+		       &error0, is_custom_app, &handoff_thread_idx))
+		{
+		case IP4_REASS_RC_OK:
+		  /* nothing to do here */
+		  break;
+		case IP4_REASS_RC_HANDOFF:
+		  next0 = IP4_FULL_REASS_NEXT_HANDOFF;
+		  b0 = vlib_get_buffer (vm, bi0);
+		  if (is_feature)
+		    vnet_buffer (b0)->ip.reass.owner_feature_thread_index =
+		      handoff_thread_idx;
+		  else
+		    vnet_buffer (b0)->ip.reass.owner_thread_index =
+		      handoff_thread_idx;
+		  break;
+		case IP4_REASS_RC_TOO_MANY_FRAGMENTS:
+		  vlib_node_increment_counter (vm, node->node_index,
+					       IP4_ERROR_REASS_FRAGMENT_CHAIN_TOO_LONG,
+					       1);
+		  ip4_full_reass_drop_all (vm, node, rm, reass);
+		  ip4_full_reass_free (rm, rt, reass);
+		  goto next_packet;
+		  break;
+		case IP4_REASS_RC_NO_BUF:
+		  vlib_node_increment_counter (vm, node->node_index,
+					       IP4_ERROR_REASS_NO_BUF, 1);
+		  ip4_full_reass_drop_all (vm, node, rm, reass);
+		  ip4_full_reass_free (rm, rt, reass);
+		  goto next_packet;
+		  break;
+		case IP4_REASS_RC_INTERNAL_ERROR:
+		  /* drop everything and start with a clean slate */
+		  vlib_node_increment_counter (vm, node->node_index,
+					       IP4_ERROR_REASS_INTERNAL_ERROR,
+					       1);
+		  ip4_full_reass_drop_all (vm, node, rm, reass);
+		  ip4_full_reass_free (rm, rt, reass);
+		  goto next_packet;
+		  break;
+		}
+	    }
+	  else
+	    {
+	      next0 = IP4_FULL_REASS_NEXT_DROP;
+	      error0 = IP4_ERROR_REASS_LIMIT_REACHED;
+	    }
+
+
+	packet_enqueue:
+	  b0->error = node->errors[error0];
+
+	  if (bi0 != ~0)
+	    {
+	      to_next[0] = bi0;
+	      to_next += 1;
+	      n_left_to_next -= 1;
+	      if (next0 == IP4_FULL_REASS_NEXT_HANDOFF)
+		{
+		  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+		    {
+		      if (is_feature)
+			ip4_full_reass_add_trace (vm, node, rm, NULL,
+						  bi0, HANDOFF, 0,
+						  vnet_buffer (b0)->ip.
+						  reass.owner_feature_thread_index);
+		      else
+			ip4_full_reass_add_trace (vm, node, rm, NULL,
+						  bi0, HANDOFF, 0,
+						  vnet_buffer (b0)->ip.
+						  reass.owner_thread_index);
+		    }
+		}
+	      else if (is_feature && IP4_ERROR_NONE == error0)
+		{
+		  b0 = vlib_get_buffer (vm, bi0);
+		  vnet_feature_next (&next0, b0);
+		}
+	      vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					       to_next, n_left_to_next,
+					       bi0, next0);
+	      IP4_REASS_DEBUG_BUFFER (bi0, enqueue_next);
+	    }
+
+	next_packet:
+	  from += 1;
+	  n_left_from -= 1;
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  clib_spinlock_unlock (&rt->lock);
+  return frame->n_vectors;
+}
+
+static char *ip4_full_reass_error_strings[] = {
+#define _(sym, string) string,
+  foreach_ip4_error
+#undef _
+};
+
+VLIB_NODE_FN (ip4_full_reass_node) (vlib_main_t * vm,
+				    vlib_node_runtime_t * node,
+				    vlib_frame_t * frame)
+{
+  return ip4_full_reass_inline (vm, node, frame, false /* is_feature */ ,
+				false /* is_custom_app */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_full_reass_node) = {
+    .name = "ip4-full-reassembly",
+    .vector_size = sizeof (u32),
+    .format_trace = format_ip4_full_reass_trace,
+    .n_errors = ARRAY_LEN (ip4_full_reass_error_strings),
+    .error_strings = ip4_full_reass_error_strings,
+    .n_next_nodes = IP4_FULL_REASS_N_NEXT,
+    .next_nodes =
+        {
+                [IP4_FULL_REASS_NEXT_INPUT] = "ip4-input",
+                [IP4_FULL_REASS_NEXT_DROP] = "ip4-drop",
+                [IP4_FULL_REASS_NEXT_HANDOFF] = "ip4-full-reassembly-handoff",
+
+        },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FN (ip4_full_reass_node_feature) (vlib_main_t * vm,
+					    vlib_node_runtime_t * node,
+					    vlib_frame_t * frame)
+{
+  return ip4_full_reass_inline (vm, node, frame, true /* is_feature */ ,
+				false /* is_custom_app */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_full_reass_node_feature) = {
+    .name = "ip4-full-reassembly-feature",
+    .vector_size = sizeof (u32),
+    .format_trace = format_ip4_full_reass_trace,
+    .n_errors = ARRAY_LEN (ip4_full_reass_error_strings),
+    .error_strings = ip4_full_reass_error_strings,
+    .n_next_nodes = IP4_FULL_REASS_N_NEXT,
+    .next_nodes =
+        {
+                [IP4_FULL_REASS_NEXT_INPUT] = "ip4-input",
+                [IP4_FULL_REASS_NEXT_DROP] = "ip4-drop",
+                [IP4_FULL_REASS_NEXT_HANDOFF] = "ip4-full-reass-feature-hoff",
+        },
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VNET_FEATURE_INIT (ip4_full_reass_feature, static) = {
+    .arc_name = "ip4-unicast",
+    .node_name = "ip4-full-reassembly-feature",
+    .runs_before = VNET_FEATURES ("ip4-lookup",
+                                  "ipsec4-input-feature"),
+    .runs_after = 0,
+};
+/* *INDENT-ON* */
+
+#ifndef CLIB_MARCH_VARIANT
+always_inline u32
+ip4_full_reass_get_nbuckets ()
+{
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+  u32 nbuckets;
+  u8 i;
+
+  nbuckets = (u32) (rm->max_reass_n / IP4_REASS_HT_LOAD_FACTOR);
+
+  for (i = 0; i < 31; i++)
+    if ((1 << i) >= nbuckets)
+      break;
+  nbuckets = 1 << i;
+
+  return nbuckets;
+}
+#endif /* CLIB_MARCH_VARIANT */
+
+typedef enum
+{
+  IP4_EVENT_CONFIG_CHANGED = 1,
+} ip4_full_reass_event_t;
+
+typedef struct
+{
+  int failure;
+  clib_bihash_16_8_t *new_hash;
+} ip4_rehash_cb_ctx;
+
+#ifndef CLIB_MARCH_VARIANT
+static void
+ip4_rehash_cb (clib_bihash_kv_16_8_t * kv, void *_ctx)
+{
+  ip4_rehash_cb_ctx *ctx = _ctx;
+  if (clib_bihash_add_del_16_8 (ctx->new_hash, kv, 1))
+    {
+      ctx->failure = 1;
+    }
+}
+
+static void
+ip4_full_reass_set_params (u32 timeout_ms, u32 max_reassemblies,
+			   u32 max_reassembly_length,
+			   u32 expire_walk_interval_ms)
+{
+  ip4_full_reass_main.timeout_ms = timeout_ms;
+  ip4_full_reass_main.timeout = (f64) timeout_ms / (f64) MSEC_PER_SEC;
+  ip4_full_reass_main.max_reass_n = max_reassemblies;
+  ip4_full_reass_main.max_reass_len = max_reassembly_length;
+  ip4_full_reass_main.expire_walk_interval_ms = expire_walk_interval_ms;
+}
+
+vnet_api_error_t
+ip4_full_reass_set (u32 timeout_ms, u32 max_reassemblies,
+		    u32 max_reassembly_length, u32 expire_walk_interval_ms)
+{
+  u32 old_nbuckets = ip4_full_reass_get_nbuckets ();
+  ip4_full_reass_set_params (timeout_ms, max_reassemblies,
+			     max_reassembly_length, expire_walk_interval_ms);
+  vlib_process_signal_event (ip4_full_reass_main.vlib_main,
+			     ip4_full_reass_main.ip4_full_reass_expire_node_idx,
+			     IP4_EVENT_CONFIG_CHANGED, 0);
+  u32 new_nbuckets = ip4_full_reass_get_nbuckets ();
+  if (ip4_full_reass_main.max_reass_n > 0 && new_nbuckets > old_nbuckets)
+    {
+      clib_bihash_16_8_t new_hash;
+      clib_memset (&new_hash, 0, sizeof (new_hash));
+      ip4_rehash_cb_ctx ctx;
+      ctx.failure = 0;
+      ctx.new_hash = &new_hash;
+      clib_bihash_init_16_8 (&new_hash, "ip4-dr", new_nbuckets,
+			     new_nbuckets * 1024);
+      clib_bihash_foreach_key_value_pair_16_8 (&ip4_full_reass_main.hash,
+					       ip4_rehash_cb, &ctx);
+      if (ctx.failure)
+	{
+	  clib_bihash_free_16_8 (&new_hash);
+	  return -1;
+	}
+      else
+	{
+	  clib_bihash_free_16_8 (&ip4_full_reass_main.hash);
+	  clib_memcpy_fast (&ip4_full_reass_main.hash, &new_hash,
+			    sizeof (ip4_full_reass_main.hash));
+	  clib_bihash_copied (&ip4_full_reass_main.hash, &new_hash);
+	}
+    }
+  return 0;
+}
+
+vnet_api_error_t
+ip4_full_reass_get (u32 * timeout_ms, u32 * max_reassemblies,
+		    u32 * max_reassembly_length,
+		    u32 * expire_walk_interval_ms)
+{
+  *timeout_ms = ip4_full_reass_main.timeout_ms;
+  *max_reassemblies = ip4_full_reass_main.max_reass_n;
+  *max_reassembly_length = ip4_full_reass_main.max_reass_len;
+  *expire_walk_interval_ms = ip4_full_reass_main.expire_walk_interval_ms;
+  return 0;
+}
+
+static clib_error_t *
+ip4_full_reass_init_function (vlib_main_t * vm)
+{
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+  clib_error_t *error = 0;
+  u32 nbuckets;
+  vlib_node_t *node;
+
+  rm->vlib_main = vm;
+
+  vec_validate (rm->per_thread_data, vlib_num_workers ());
+  ip4_full_reass_per_thread_t *rt;
+  vec_foreach (rt, rm->per_thread_data)
+  {
+    clib_spinlock_init (&rt->lock);
+    pool_alloc (rt->pool, rm->max_reass_n);
+  }
+
+  node = vlib_get_node_by_name (vm, (u8 *) "ip4-full-reassembly-expire-walk");
+  ASSERT (node);
+  rm->ip4_full_reass_expire_node_idx = node->index;
+
+  ip4_full_reass_set_params (IP4_REASS_TIMEOUT_DEFAULT_MS,
+			     IP4_REASS_MAX_REASSEMBLIES_DEFAULT,
+			     IP4_REASS_MAX_REASSEMBLY_LENGTH_DEFAULT,
+			     IP4_REASS_EXPIRE_WALK_INTERVAL_DEFAULT_MS);
+
+  nbuckets = ip4_full_reass_get_nbuckets ();
+  clib_bihash_init_16_8 (&rm->hash, "ip4-dr", nbuckets, nbuckets * 1024);
+
+  node = vlib_get_node_by_name (vm, (u8 *) "ip4-drop");
+  ASSERT (node);
+  rm->ip4_drop_idx = node->index;
+
+  rm->fq_index = vlib_frame_queue_main_init (ip4_full_reass_node.index, 0);
+  rm->fq_feature_index =
+    vlib_frame_queue_main_init (ip4_full_reass_node_feature.index, 0);
+
+  return error;
+}
+
+VLIB_INIT_FUNCTION (ip4_full_reass_init_function);
+#endif /* CLIB_MARCH_VARIANT */
+
+static uword
+ip4_full_reass_walk_expired (vlib_main_t * vm,
+			     vlib_node_runtime_t * node, vlib_frame_t * f)
+{
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+  uword event_type, *event_data = 0;
+
+  while (true)
+    {
+      vlib_process_wait_for_event_or_clock (vm,
+					    (f64)
+					    rm->expire_walk_interval_ms /
+					    (f64) MSEC_PER_SEC);
+      event_type = vlib_process_get_events (vm, &event_data);
+
+      switch (event_type)
+	{
+	case ~0:		/* no events => timeout */
+	  /* nothing to do here */
+	  break;
+	case IP4_EVENT_CONFIG_CHANGED:
+	  break;
+	default:
+	  clib_warning ("BUG: event type 0x%wx", event_type);
+	  break;
+	}
+      f64 now = vlib_time_now (vm);
+
+      ip4_full_reass_t *reass;
+      int *pool_indexes_to_free = NULL;
+
+      uword thread_index = 0;
+      int index;
+      const uword nthreads = vlib_num_workers () + 1;
+      for (thread_index = 0; thread_index < nthreads; ++thread_index)
+	{
+	  ip4_full_reass_per_thread_t *rt =
+	    &rm->per_thread_data[thread_index];
+	  clib_spinlock_lock (&rt->lock);
+
+	  vec_reset_length (pool_indexes_to_free);
+          /* *INDENT-OFF* */
+          pool_foreach_index (index, rt->pool, ({
+                                reass = pool_elt_at_index (rt->pool, index);
+                                if (now > reass->last_heard + rm->timeout)
+                                  {
+                                    vec_add1 (pool_indexes_to_free, index);
+                                  }
+                              }));
+          /* *INDENT-ON* */
+	  int *i;
+          /* *INDENT-OFF* */
+          vec_foreach (i, pool_indexes_to_free)
+          {
+            ip4_full_reass_t *reass = pool_elt_at_index (rt->pool, i[0]);
+            ip4_full_reass_drop_all (vm, node, rm, reass);
+            ip4_full_reass_free (rm, rt, reass);
+          }
+          /* *INDENT-ON* */
+
+	  clib_spinlock_unlock (&rt->lock);
+	}
+
+      vec_free (pool_indexes_to_free);
+      if (event_data)
+	{
+	  _vec_len (event_data) = 0;
+	}
+    }
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_full_reass_expire_node) = {
+    .function = ip4_full_reass_walk_expired,
+    .type = VLIB_NODE_TYPE_PROCESS,
+    .name = "ip4-full-reassembly-expire-walk",
+    .format_trace = format_ip4_full_reass_trace,
+    .n_errors = ARRAY_LEN (ip4_full_reass_error_strings),
+    .error_strings = ip4_full_reass_error_strings,
+
+};
+/* *INDENT-ON* */
+
+static u8 *
+format_ip4_full_reass_key (u8 * s, va_list * args)
+{
+  ip4_full_reass_key_t *key = va_arg (*args, ip4_full_reass_key_t *);
+  s =
+    format (s,
+	    "xx_id: %u, src: %U, dst: %U, frag_id: %u, proto: %u",
+	    key->xx_id, format_ip4_address, &key->src, format_ip4_address,
+	    &key->dst, clib_net_to_host_u16 (key->frag_id), key->proto);
+  return s;
+}
+
+static u8 *
+format_ip4_reass (u8 * s, va_list * args)
+{
+  vlib_main_t *vm = va_arg (*args, vlib_main_t *);
+  ip4_full_reass_t *reass = va_arg (*args, ip4_full_reass_t *);
+
+  s = format (s, "ID: %lu, key: %U\n  first_bi: %u, data_len: %u, "
+	      "last_packet_octet: %u, trace_op_counter: %u\n",
+	      reass->id, format_ip4_full_reass_key, &reass->key,
+	      reass->first_bi, reass->data_len,
+	      reass->last_packet_octet, reass->trace_op_counter);
+
+  u32 bi = reass->first_bi;
+  u32 counter = 0;
+  while (~0 != bi)
+    {
+      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
+      vnet_buffer_opaque_t *vnb = vnet_buffer (b);
+      s =
+	format (s,
+		"  #%03u: range: [%u, %u], bi: %u, off: %d, len: %u, "
+		"fragment[%u, %u]\n", counter, vnb->ip.reass.range_first,
+		vnb->ip.reass.range_last, bi,
+		ip4_full_reass_buffer_get_data_offset (b),
+		ip4_full_reass_buffer_get_data_len (b),
+		vnb->ip.reass.fragment_first, vnb->ip.reass.fragment_last);
+      if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+	{
+	  bi = b->next_buffer;
+	}
+      else
+	{
+	  bi = ~0;
+	}
+    }
+  return s;
+}
+
+static clib_error_t *
+show_ip4_reass (vlib_main_t * vm,
+		unformat_input_t * input,
+		CLIB_UNUSED (vlib_cli_command_t * lmd))
+{
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+
+  vlib_cli_output (vm, "---------------------");
+  vlib_cli_output (vm, "IP4 reassembly status");
+  vlib_cli_output (vm, "---------------------");
+  bool details = false;
+  if (unformat (input, "details"))
+    {
+      details = true;
+    }
+
+  u32 sum_reass_n = 0;
+  ip4_full_reass_t *reass;
+  uword thread_index;
+  const uword nthreads = vlib_num_workers () + 1;
+  for (thread_index = 0; thread_index < nthreads; ++thread_index)
+    {
+      ip4_full_reass_per_thread_t *rt = &rm->per_thread_data[thread_index];
+      clib_spinlock_lock (&rt->lock);
+      if (details)
+	{
+          /* *INDENT-OFF* */
+          pool_foreach (reass, rt->pool, {
+            vlib_cli_output (vm, "%U", format_ip4_reass, vm, reass);
+          });
+          /* *INDENT-ON* */
+	}
+      sum_reass_n += rt->reass_n;
+      clib_spinlock_unlock (&rt->lock);
+    }
+  vlib_cli_output (vm, "---------------------");
+  vlib_cli_output (vm, "Current IP4 reassemblies count: %lu\n",
+		   (long unsigned) sum_reass_n);
+  vlib_cli_output (vm,
+		   "Maximum configured concurrent IP4 reassemblies per worker-thread: %lu\n",
+		   (long unsigned) rm->max_reass_n);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_ip4_full_reass_cmd, static) = {
+    .path = "show ip4-full-reassembly",
+    .short_help = "show ip4-full-reassembly [details]",
+    .function = show_ip4_reass,
+};
+/* *INDENT-ON* */
+
+#ifndef CLIB_MARCH_VARIANT
+vnet_api_error_t
+ip4_full_reass_enable_disable (u32 sw_if_index, u8 enable_disable)
+{
+  return vnet_feature_enable_disable ("ip4-unicast",
+				      "ip4-full-reassembly-feature",
+				      sw_if_index, enable_disable, 0, 0);
+}
+#endif /* CLIB_MARCH_VARIANT */
+
+
+#define foreach_ip4_full_reass_handoff_error                       \
+_(CONGESTION_DROP, "congestion drop")
+
+
+typedef enum
+{
+#define _(sym,str) IP4_FULL_REASS_HANDOFF_ERROR_##sym,
+  foreach_ip4_full_reass_handoff_error
+#undef _
+    IP4_FULL_REASS_HANDOFF_N_ERROR,
+} ip4_full_reass_handoff_error_t;
+
+static char *ip4_full_reass_handoff_error_strings[] = {
+#define _(sym,string) string,
+  foreach_ip4_full_reass_handoff_error
+#undef _
+};
+
+typedef struct
+{
+  u32 next_worker_index;
+} ip4_full_reass_handoff_trace_t;
+
+static u8 *
+format_ip4_full_reass_handoff_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 *);
+  ip4_full_reass_handoff_trace_t *t =
+    va_arg (*args, ip4_full_reass_handoff_trace_t *);
+
+  s =
+    format (s, "ip4-full-reassembly-handoff: next-worker %d",
+	    t->next_worker_index);
+
+  return s;
+}
+
+always_inline uword
+ip4_full_reass_handoff_node_inline (vlib_main_t * vm,
+				    vlib_node_runtime_t * node,
+				    vlib_frame_t * frame, bool is_feature)
+{
+  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
+
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  u32 n_enq, n_left_from, *from;
+  u16 thread_indices[VLIB_FRAME_SIZE], *ti;
+  u32 fq_index;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  vlib_get_buffers (vm, from, bufs, n_left_from);
+
+  b = bufs;
+  ti = thread_indices;
+
+  fq_index = (is_feature) ? rm->fq_feature_index : rm->fq_index;
+
+  while (n_left_from > 0)
+    {
+      ti[0] =
+	(is_feature) ? vnet_buffer (b[0])->ip.
+	reass.owner_feature_thread_index : vnet_buffer (b[0])->ip.
+	reass.owner_thread_index;
+
+      if (PREDICT_FALSE
+	  ((node->flags & VLIB_NODE_FLAG_TRACE)
+	   && (b[0]->flags & VLIB_BUFFER_IS_TRACED)))
+	{
+	  ip4_full_reass_handoff_trace_t *t =
+	    vlib_add_trace (vm, node, b[0], sizeof (*t));
+	  t->next_worker_index = ti[0];
+	}
+
+      n_left_from -= 1;
+      ti += 1;
+      b += 1;
+    }
+  n_enq =
+    vlib_buffer_enqueue_to_thread (vm, fq_index, from, thread_indices,
+				   frame->n_vectors, 1);
+
+  if (n_enq < frame->n_vectors)
+    vlib_node_increment_counter (vm, node->node_index,
+				 IP4_FULL_REASS_HANDOFF_ERROR_CONGESTION_DROP,
+				 frame->n_vectors - n_enq);
+  return frame->n_vectors;
+}
+
+VLIB_NODE_FN (ip4_full_reass_handoff_node) (vlib_main_t * vm,
+					    vlib_node_runtime_t * node,
+					    vlib_frame_t * frame)
+{
+  return ip4_full_reass_handoff_node_inline (vm, node, frame,
+					     false /* is_feature */ );
+}
+
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_full_reass_handoff_node) = {
+  .name = "ip4-full-reassembly-handoff",
+  .vector_size = sizeof (u32),
+  .n_errors = ARRAY_LEN(ip4_full_reass_handoff_error_strings),
+  .error_strings = ip4_full_reass_handoff_error_strings,
+  .format_trace = format_ip4_full_reass_handoff_trace,
+
+  .n_next_nodes = 1,
+
+  .next_nodes = {
+    [0] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+
+/* *INDENT-OFF* */
+VLIB_NODE_FN (ip4_full_reass_feature_handoff_node) (vlib_main_t * vm,
+						    vlib_node_runtime_t *
+						    node,
+						    vlib_frame_t * frame)
+{
+  return ip4_full_reass_handoff_node_inline (vm, node, frame,
+					     true /* is_feature */ );
+}
+/* *INDENT-ON* */
+
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_full_reass_feature_handoff_node) = {
+  .name = "ip4-full-reass-feature-hoff",
+  .vector_size = sizeof (u32),
+  .n_errors = ARRAY_LEN(ip4_full_reass_handoff_error_strings),
+  .error_strings = ip4_full_reass_handoff_error_strings,
+  .format_trace = format_ip4_full_reass_handoff_trace,
+
+  .n_next_nodes = 1,
+
+  .next_nodes = {
+    [0] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */