text: /*
   * 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 Reassembly.
   *
   * This file contains the source code for IPv4 reassembly.
   */
  
  #include <vppinfra/vec.h>
  #include <vnet/vnet.h>
  #include <vnet/ip/ip.h>
  #include <vppinfra/bihash_16_8.h>
  #include <vnet/ip/ip4_reassembly.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_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_INTERNAL_ERROR,
    IP4_REASS_RC_NO_BUF,
  } ip4_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_reass_key_t;
  
  typedef union
  {
    struct
    {
      u32 reass_index;
      u32 thread_index;
    };
    u64 as_u64;
  } ip4_reass_val_t;
  
  typedef union
  {
    struct
    {
      ip4_reass_key_t k;
      ip4_reass_val_t v;
    };
    clib_bihash_kv_16_8_t kv;
  } ip4_reass_kv_t;
  
  always_inline u32
  ip4_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_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_reass_buffer_get_data_offset (b)) + 1;
  }
  
  typedef struct
  {
    // hash table key
    ip4_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
    u8 next_index;
    // minimum fragment length for this reassembly - used to estimate MTU
    u16 min_fragment_length;
  
  } ip4_reass_t;
  
  typedef struct
  {
    ip4_reass_t *pool;
    u32 reass_n;
    u32 id_counter;
    clib_spinlock_t lock;
  } ip4_reass_per_thread_t;
  
  typedef struct
  {
    // IPv4 config
    u32 timeout_ms;
    f64 timeout;
    u32 expire_walk_interval_ms;
    u32 max_reass_n;
  
    // IPv4 runtime
    clib_bihash_16_8_t hash;
    // per-thread data
    ip4_reass_per_thread_t *per_thread_data;
  
    // convenience
    vlib_main_t *vlib_main;
    vnet_main_t *vnet_main;
  
    // node index of ip4-drop node
    u32 ip4_drop_idx;
    u32 ip4_reass_expire_node_idx;
  
    /** Worker handoff */
    u32 fq_index;
    u32 fq_feature_index;
  
  } ip4_reass_main_t;
  
  extern ip4_reass_main_t ip4_reass_main;
  
  #ifndef CLIB_MARCH_VARIANT
  ip4_reass_main_t ip4_reass_main;
  #endif /* CLIB_MARCH_VARIANT */
  
  typedef enum
  {
    IP4_REASSEMBLY_NEXT_INPUT,
    IP4_REASSEMBLY_NEXT_DROP,
    IP4_REASSEMBLY_NEXT_HANDOFF,
    IP4_REASSEMBLY_N_NEXT,
  } ip4_reass_next_t;
  
  typedef enum
  {
    RANGE_NEW,
    RANGE_SHRINK,
    RANGE_DISCARD,
    RANGE_OVERLAP,
    FINALIZE,
  } ip4_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_reass_range_trace_t;
  
  typedef struct
  {
    ip4_reass_trace_operation_e action;
    u32 reass_id;
    ip4_reass_range_trace_t trace_range;
    u32 size_diff;
    u32 op_id;
    u32 fragment_first;
    u32 fragment_last;
    u32 total_data_len;
  } ip4_reass_trace_t;
  
  extern vlib_node_registration_t ip4_reass_node;
  extern vlib_node_registration_t ip4_reass_node_feature;
  
  static void
  ip4_reass_trace_details (vlib_main_t * vm, u32 bi,
  			 ip4_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_reass_buffer_get_data_offset (b);
    trace->data_len = ip4_reass_buffer_get_data_len (b);
    trace->range_bi = bi;
  }
  
  static u8 *
  format_ip4_reass_range_trace (u8 * s, va_list * args)
  {
    ip4_reass_range_trace_t *trace = va_arg (*args, ip4_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_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_reass_trace_t *t = va_arg (*args, ip4_reass_trace_t *);
    s = format (s, "reass id: %u, op id: %u ", t->reass_id, t->op_id);
    u32 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_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_reass_range_trace, &t->trace_range);
        break;
      case RANGE_NEW:
        s = format (s, "\n%Unew %U", format_white_space, indent,
  		  format_ip4_reass_range_trace, &t->trace_range);
        break;
      case RANGE_OVERLAP:
        s = format (s, "\n%Uoverlapping/ignored %U", format_white_space, indent,
  		  format_ip4_reass_range_trace, &t->trace_range);
        break;
      case FINALIZE:
        s = format (s, "\n%Ufinalize reassembly", format_white_space, indent);
        break;
      }
    return s;
  }
  
  static void
  ip4_reass_add_trace (vlib_main_t * vm, vlib_node_runtime_t * node,
  		     ip4_reass_main_t * rm, ip4_reass_t * reass, u32 bi,
  		     ip4_reass_trace_operation_e action, u32 size_diff)
  {
    vlib_buffer_t *b = vlib_get_buffer (vm, bi);
    vnet_buffer_opaque_t *vnb = vnet_buffer (b);
    if (pool_is_free_index (vm->trace_main.trace_buffer_pool, b->trace_index))
      {
        // this buffer's trace is gone
        b->flags &= ~VLIB_BUFFER_IS_TRACED;
        return;
      }
    ip4_reass_trace_t *t = vlib_add_trace (vm, node, b, sizeof (t[0]));
    t->reass_id = reass->id;
    t->action = action;
    ip4_reass_trace_details (vm, bi, &t->trace_range);
    t->size_diff = size_diff;
    t->op_id = reass->trace_op_counter;
    ++reass->trace_op_counter;
    t->fragment_first = vnb->ip.reass.fragment_first;
    t->fragment_last = vnb->ip.reass.fragment_last;
    t->trace_range.first_bi = reass->first_bi;
    t->total_data_len = reass->data_len;
  #if 0
    static u8 *s = NULL;
    s = format (s, "%U", format_ip4_reass_trace, NULL, NULL, t);
    printf ("%.*s\n", vec_len (s), s);
    fflush (stdout);
    vec_reset_length (s);
  #endif
  }
  
  
  always_inline void
  ip4_reass_free (ip4_reass_main_t * rm, ip4_reass_per_thread_t * rt,
  		ip4_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);
    pool_put (rt->pool, reass);
    --rt->reass_n;
  }
  
  always_inline void
  ip4_reass_on_timeout (vlib_main_t * vm, ip4_reass_main_t * rm,
  		      ip4_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;
      }
    vlib_buffer_free (vm, to_free, vec_len (to_free));
    vec_free (to_free);
  }
  
  static ip4_reass_t *
  ip4_reass_find_or_create (vlib_main_t * vm, ip4_reass_main_t * rm,
  			  ip4_reass_per_thread_t * rt, ip4_reass_kv_t * kv,
  			  u8 * do_handoff)
  {
    ip4_reass_t *reass = NULL;
    f64 now = vlib_time_now (rm->vlib_main);
  
    if (!clib_bihash_search_16_8
        (&rm->hash, (clib_bihash_kv_16_8_t *) kv, (clib_bihash_kv_16_8_t *) kv))
      {
        if (vm->thread_index != kv->v.thread_index)
  	{
  	  *do_handoff = 1;
  	  return NULL;
  	}
        reass = pool_elt_at_index (rt->pool, kv->v.reass_index);
  
        if (now > reass->last_heard + rm->timeout)
  	{
  	  ip4_reass_on_timeout (vm, rm, reass);
  	  ip4_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;
        ++rt->id_counter;
        reass->first_bi = ~0;
        reass->last_packet_octet = ~0;
        reass->data_len = 0;
        ++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.thread_index = vm->thread_index;
    reass->last_heard = now;
  
    if (clib_bihash_add_del_16_8 (&rm->hash, (clib_bihash_kv_16_8_t *) kv, 1))
      {
        ip4_reass_free (rm, rt, reass);
        reass = NULL;
      }
  
    return reass;
  }
  
  always_inline ip4_reass_rc_t
  ip4_reass_finalize (vlib_main_t * vm, vlib_node_runtime_t * node,
  		    ip4_reass_main_t * rm, ip4_reass_per_thread_t * rt,
  		    ip4_reass_t * reass, u32 * bi0, u32 * next0, u32 * error0,
  		    bool is_feature)
  {
    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_reass_buffer_get_data_len (tmp);
        u32 trim_front =
  	ip4_header_bytes (ip) + ip4_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_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 */
  		  vlib_buffer_free_one (vm, 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 = vlib_get_buffer (vm, tmp_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;
  	    }
  	  else
  	    {
  	      vlib_buffer_free_one (vm, tmp_bi);
  	      if (reass->first_bi == tmp_bi)
  		{
  		  return IP4_REASS_RC_INTERNAL_ERROR;
  		}
  	    }
  	  if (tmp->flags & VLIB_BUFFER_NEXT_PRESENT)
  	    {
  	      tmp_bi = tmp->next_buffer;
  	      tmp = vlib_get_buffer (vm, tmp->next_buffer);
  	    }
  	  else
  	    {
  	      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;
      }
  
    if (PREDICT_FALSE (first_b->flags & VLIB_BUFFER_IS_TRACED))
      {
        ip4_reass_add_trace (vm, node, rm, reass, reass->first_bi, FINALIZE, 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_feature)
      {
        *next0 = IP4_REASSEMBLY_NEXT_INPUT;
      }
    else
      {
        *next0 = reass->next_index;
      }
    vnet_buffer (first_b)->ip.reass.estimated_mtu = reass->min_fragment_length;
    *error0 = IP4_ERROR_NONE;
    ip4_reass_free (rm, rt, reass);
    reass = NULL;
    return IP4_REASS_RC_OK;
  }
  
  always_inline ip4_reass_rc_t
  ip4_reass_insert_range_in_chain (vlib_main_t * vm,
  				 ip4_reass_main_t * rm,
  				 ip4_reass_per_thread_t * rt,
  				 ip4_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_reass_buffer_get_data_len (new_next_b);
    return IP4_REASS_RC_OK;
  }
  
  always_inline ip4_reass_rc_t
  ip4_reass_remove_range_from_chain (vlib_main_t * vm,
  				   vlib_node_runtime_t * node,
  				   ip4_reass_main_t * rm,
  				   ip4_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_reass_buffer_get_data_len (discard_b);
    while (1)
      {
        vlib_buffer_free_one (vm, discard_bi);
        if (PREDICT_FALSE (discard_b->flags & VLIB_BUFFER_IS_TRACED))
  	{
  	  ip4_reass_add_trace (vm, node, rm, reass, discard_bi, RANGE_DISCARD,
  			       0);
  	}
        if (discard_b->flags & VLIB_BUFFER_NEXT_PRESENT)
  	{
  	  discard_b->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
  	  discard_bi = discard_b->next_buffer;
  	  discard_b = vlib_get_buffer (vm, discard_bi);
  	}
        else
  	{
  	  break;
  	}
      }
    return IP4_REASS_RC_OK;
  }
  
  always_inline ip4_reass_rc_t
  ip4_reass_update (vlib_main_t * vm, vlib_node_runtime_t * node,
  		  ip4_reass_main_t * rm, ip4_reass_per_thread_t * rt,
  		  ip4_reass_t * reass, u32 * bi0, u32 * next0, u32 * error0,
  		  bool is_feature)
  {
    ip4_reass_rc_t rc = IP4_REASS_RC_OK;
    int consumed = 0;
    vlib_buffer_t *fb = vlib_get_buffer (vm, *bi0);
    ip4_header_t *fip = vlib_buffer_get_current (fb);
    vnet_buffer_opaque_t *fvnb = vnet_buffer (fb);
    reass->next_index = fvnb->ip.reass.next_index;	// store next_index before it's overwritten
    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_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_reass_add_trace (vm, node, rm, reass, *bi0, RANGE_NEW, 0);
  	}
        *bi0 = ~0;
        reass->min_fragment_length = clib_net_to_host_u16 (fip->length);
        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_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_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_reass_add_trace (vm, node, rm, reass, *bi0,
  				       RANGE_OVERLAP, 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_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_reass_add_trace (vm, node, rm, reass,
  					   candidate_range_bi, RANGE_SHRINK,
  					   overlap);
  		    }
  		  rc =
  		    ip4_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_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_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_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_reass_insert_range_in_chain (vm, rm, rt, reass,
  						     prev_range_bi, *bi0);
  		  if (IP4_REASS_RC_OK != rc)
  		    {
  		      return rc;
  		    }
  		  consumed = 1;
  		}
  	    }
  	}
        break;
      }
    if (consumed)
      {
        if (PREDICT_FALSE (fb->flags & VLIB_BUFFER_IS_TRACED))
  	{
  	  ip4_reass_add_trace (vm, node, rm, reass, *bi0, RANGE_NEW, 0);
  	}
      }
    if (~0 != reass->last_packet_octet &&
        reass->data_len == reass->last_packet_octet + 1)
      {
        return ip4_reass_finalize (vm, node, rm, rt, reass, bi0, next0, error0,
  				 is_feature);
      }
    else
      {
        if (consumed)
  	{
  	  *bi0 = ~0;
  	}
        else
  	{
  	  *next0 = IP4_REASSEMBLY_NEXT_DROP;
  	  *error0 = IP4_ERROR_REASS_DUPLICATE_FRAGMENT;
  	}
      }
    return rc;
  }
  
  always_inline uword
  ip4_reassembly_inline (vlib_main_t * vm,
  		       vlib_node_runtime_t * node,
  		       vlib_frame_t * frame, bool is_feature)
  {
    u32 *from = vlib_frame_vector_args (frame);
    u32 n_left_from, n_left_to_next, *to_next, next_index;
    ip4_reass_main_t *rm = &ip4_reass_main;
    ip4_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_feature)
  		{
  		  next0 = IP4_REASSEMBLY_NEXT_INPUT;
  		}
  	      else
  		{
  		  next0 = vnet_buffer (b0)->ip.reass.next_index;
  		}
  	    }
  	  else
  	    {
  	      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_REASSEMBLY_NEXT_DROP;
  		  error0 = IP4_ERROR_REASS_MALFORMED_PACKET;
  		}
  	      else
  		{
  		  ip4_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_reass_t *reass =
  		    ip4_reass_find_or_create (vm, rm, rt, &kv, &do_handoff);
  
  		  if (PREDICT_FALSE (do_handoff))
  		    {
  		      next0 = IP4_REASSEMBLY_NEXT_HANDOFF;
  		      if (is_feature)
  			vnet_buffer (b0)->ip.
  			  reass.owner_feature_thread_index =
  			  kv.v.thread_index;
  		      else
  			vnet_buffer (b0)->ip.reass.owner_thread_index =
  			  kv.v.thread_index;
  		    }
  		  else if (reass)
  		    {
  		      switch (ip4_reass_update
  			      (vm, node, rm, rt, reass, &bi0, &next0,
  			       &error0, is_feature))
  			{
  			case IP4_REASS_RC_OK:
  			  /* nothing to do here */
  			  break;
  			case IP4_REASS_RC_NO_BUF:
  			  /* fallthrough */
  			case IP4_REASS_RC_INTERNAL_ERROR:
  			  /* drop everything and start with a clean slate */
  			  ip4_reass_on_timeout (vm, rm, reass);
  			  ip4_reass_free (rm, rt, reass);
  			  goto next_packet;
  			  break;
  			}
  		    }
  		  else
  		    {
  		      next0 = IP4_REASSEMBLY_NEXT_DROP;
  		      error0 = IP4_ERROR_REASS_LIMIT_REACHED;
  		    }
  		}
  
  	      b0->error = node->errors[error0];
  	    }
  
  	  if (bi0 != ~0)
  	    {
  	      to_next[0] = bi0;
  	      to_next += 1;
  	      n_left_to_next -= 1;
  	      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_reassembly_error_strings[] = {
  #define _(sym, string) string,
    foreach_ip4_error
  #undef _
  };
  
  VLIB_NODE_FN (ip4_reass_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
  			       vlib_frame_t * frame)
  {
    return ip4_reassembly_inline (vm, node, frame, false /* is_feature */ );
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (ip4_reass_node) = {
      .name = "ip4-reassembly",
      .vector_size = sizeof (u32),
      .format_trace = format_ip4_reass_trace,
      .n_errors = ARRAY_LEN (ip4_reassembly_error_strings),
      .error_strings = ip4_reassembly_error_strings,
      .n_next_nodes = IP4_REASSEMBLY_N_NEXT,
      .next_nodes =
          {
                  [IP4_REASSEMBLY_NEXT_INPUT] = "ip4-input",
                  [IP4_REASSEMBLY_NEXT_DROP] = "ip4-drop",
                  [IP4_REASSEMBLY_NEXT_HANDOFF] = "ip4-reassembly-handoff",
  
          },
  };
  /* *INDENT-ON* */
  
  VLIB_NODE_FN (ip4_reass_node_feature) (vlib_main_t * vm,
  				       vlib_node_runtime_t * node,
  				       vlib_frame_t * frame)
  {
    return ip4_reassembly_inline (vm, node, frame, true /* is_feature */ );
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (ip4_reass_node_feature) = {
      .name = "ip4-reassembly-feature",
      .vector_size = sizeof (u32),
      .format_trace = format_ip4_reass_trace,
      .n_errors = ARRAY_LEN (ip4_reassembly_error_strings),
      .error_strings = ip4_reassembly_error_strings,
      .n_next_nodes = IP4_REASSEMBLY_N_NEXT,
      .next_nodes =
          {
                  [IP4_REASSEMBLY_NEXT_INPUT] = "ip4-input",
                  [IP4_REASSEMBLY_NEXT_DROP] = "ip4-drop",
                  [IP4_REASSEMBLY_NEXT_HANDOFF] = "ip4-reass-feature-hoff",
          },
  };
  /* *INDENT-ON* */
  
  /* *INDENT-OFF* */
  VNET_FEATURE_INIT (ip4_reassembly_feature, static) = {
      .arc_name = "ip4-unicast",
      .node_name = "ip4-reassembly-feature",
      .runs_before = VNET_FEATURES ("ip4-lookup"),
      .runs_after = 0,
  };
  /* *INDENT-ON* */
  
  #ifndef CLIB_MARCH_VARIANT
  always_inline u32
  ip4_reass_get_nbuckets ()
  {
    ip4_reass_main_t *rm = &ip4_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_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_reass_set_params (u32 timeout_ms, u32 max_reassemblies,
  		      u32 expire_walk_interval_ms)
  {
    ip4_reass_main.timeout_ms = timeout_ms;
    ip4_reass_main.timeout = (f64) timeout_ms / (f64) MSEC_PER_SEC;
    ip4_reass_main.max_reass_n = max_reassemblies;
    ip4_reass_main.expire_walk_interval_ms = expire_walk_interval_ms;
  }
  
  vnet_api_error_t
  ip4_reass_set (u32 timeout_ms, u32 max_reassemblies,
  	       u32 expire_walk_interval_ms)
  {
    u32 old_nbuckets = ip4_reass_get_nbuckets ();
    ip4_reass_set_params (timeout_ms, max_reassemblies,
  			expire_walk_interval_ms);
    vlib_process_signal_event (ip4_reass_main.vlib_main,
  			     ip4_reass_main.ip4_reass_expire_node_idx,
  			     IP4_EVENT_CONFIG_CHANGED, 0);
    u32 new_nbuckets = ip4_reass_get_nbuckets ();
    if (ip4_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-reass", new_nbuckets,
  			     new_nbuckets * 1024);
        clib_bihash_foreach_key_value_pair_16_8 (&ip4_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_reass_main.hash);
  	  clib_memcpy_fast (&ip4_reass_main.hash, &new_hash,
  			    sizeof (ip4_reass_main.hash));
  	}
      }
    return 0;
  }
  
  vnet_api_error_t
  ip4_reass_get (u32 * timeout_ms, u32 * max_reassemblies,
  	       u32 * expire_walk_interval_ms)
  {
    *timeout_ms = ip4_reass_main.timeout_ms;
    *max_reassemblies = ip4_reass_main.max_reass_n;
    *expire_walk_interval_ms = ip4_reass_main.expire_walk_interval_ms;
    return 0;
  }
  
  static clib_error_t *
  ip4_reass_init_function (vlib_main_t * vm)
  {
    ip4_reass_main_t *rm = &ip4_reass_main;
    clib_error_t *error = 0;
    u32 nbuckets;
    vlib_node_t *node;
  
    rm->vlib_main = vm;
    rm->vnet_main = vnet_get_main ();
  
    vec_validate (rm->per_thread_data, vlib_num_workers ());
    ip4_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-reassembly-expire-walk");
    ASSERT (node);
    rm->ip4_reass_expire_node_idx = node->index;
  
    ip4_reass_set_params (IP4_REASS_TIMEOUT_DEFAULT_MS,
  			IP4_REASS_MAX_REASSEMBLIES_DEFAULT,
  			IP4_REASS_EXPIRE_WALK_INTERVAL_DEFAULT_MS);
  
    nbuckets = ip4_reass_get_nbuckets ();
    clib_bihash_init_16_8 (&rm->hash, "ip4-reass", 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_reass_node.index, 0);
    rm->fq_feature_index =
      vlib_frame_queue_main_init (ip4_reass_node_feature.index, 0);
  
  
    return error;
  }
  
  VLIB_INIT_FUNCTION (ip4_reass_init_function);
  #endif /* CLIB_MARCH_VARIANT */
  
  static uword
  ip4_reass_walk_expired (vlib_main_t * vm,
  			vlib_node_runtime_t * node, vlib_frame_t * f)
  {
    ip4_reass_main_t *rm = &ip4_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_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_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_reass_t *reass = pool_elt_at_index (rt->pool, i[0]);
              ip4_reass_on_timeout (vm, rm, reass);
              ip4_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_reass_expire_node, static) = {
      .function = ip4_reass_walk_expired,
      .type = VLIB_NODE_TYPE_PROCESS,
      .name = "ip4-reassembly-expire-walk",
      .format_trace = format_ip4_reass_trace,
      .n_errors = ARRAY_LEN (ip4_reassembly_error_strings),
      .error_strings = ip4_reassembly_error_strings,
  
  };
  /* *INDENT-ON* */
  
  static u8 *
  format_ip4_reass_key (u8 * s, va_list * args)
  {
    ip4_reass_key_t *key = va_arg (*args, ip4_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_reass_t *reass = va_arg (*args, ip4_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_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_reass_buffer_get_data_offset (b),
  		  ip4_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_reass_main_t *rm = &ip4_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_reass_t *reass;
    uword thread_index;
    const uword nthreads = vlib_num_workers () + 1;
    for (thread_index = 0; thread_index < nthreads; ++thread_index)
      {
        ip4_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_reassembly_cmd, static) = {
      .path = "show ip4-reassembly",
      .short_help = "show ip4-reassembly [details]",
      .function = show_ip4_reass,
  };
  /* *INDENT-ON* */
  
  #ifndef CLIB_MARCH_VARIANT
  vnet_api_error_t
  ip4_reass_enable_disable (u32 sw_if_index, u8 enable_disable)
  {
    return vnet_feature_enable_disable ("ip4-unicast",
  				      "ip4-reassembly-feature", sw_if_index,
  				      enable_disable, 0, 0);
  }
  #endif /* CLIB_MARCH_VARIANT */
  
  
  #define foreach_ip4_reassembly_handoff_error                       \
  _(CONGESTION_DROP, "congestion drop")
  
  
  typedef enum
  {
  #define _(sym,str) IP4_REASSEMBLY_HANDOFF_ERROR_##sym,
    foreach_ip4_reassembly_handoff_error
  #undef _
      IP4_REASSEMBLY_HANDOFF_N_ERROR,
  } ip4_reassembly_handoff_error_t;
  
  static char *ip4_reassembly_handoff_error_strings[] = {
  #define _(sym,string) string,
    foreach_ip4_reassembly_handoff_error
  #undef _
  };
  
  typedef struct
  {
    u32 next_worker_index;
  } ip4_reassembly_handoff_trace_t;
  
  static u8 *
  format_ip4_reassembly_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_reassembly_handoff_trace_t *t =
      va_arg (*args, ip4_reassembly_handoff_trace_t *);
  
    s =
      format (s, "ip4-reassembly-handoff: next-worker %d",
  	    t->next_worker_index);
  
    return s;
  }
  
  always_inline uword
  ip4_reassembly_handoff_node_inline (vlib_main_t * vm,
  				    vlib_node_runtime_t * node,
  				    vlib_frame_t * frame, bool is_feature)
  {
    ip4_reass_main_t *rm = &ip4_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_reassembly_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_REASSEMBLY_HANDOFF_ERROR_CONGESTION_DROP,
  				 frame->n_vectors - n_enq);
    return frame->n_vectors;
  }
  
  VLIB_NODE_FN (ip4_reassembly_handoff_node) (vlib_main_t * vm,
  					    vlib_node_runtime_t * node,
  					    vlib_frame_t * frame)
  {
    return ip4_reassembly_handoff_node_inline (vm, node, frame,
  					     false /* is_feature */ );
  }
  
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (ip4_reassembly_handoff_node) = {
    .name = "ip4-reassembly-handoff",
    .vector_size = sizeof (u32),
    .n_errors = ARRAY_LEN(ip4_reassembly_handoff_error_strings),
    .error_strings = ip4_reassembly_handoff_error_strings,
    .format_trace = format_ip4_reassembly_handoff_trace,
  
    .n_next_nodes = 1,
  
    .next_nodes = {
      [0] = "error-drop",
    },
  };
  /* *INDENT-ON* */
  
  
  /* *INDENT-OFF* */
  VLIB_NODE_FN (ip4_reassembly_feature_handoff_node) (vlib_main_t * vm,
  						    vlib_node_runtime_t *
  						    node,
  						    vlib_frame_t * frame)
  {
    return ip4_reassembly_handoff_node_inline (vm, node, frame,
  					     true /* is_feature */ );
  }
  /* *INDENT-ON* */
  
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (ip4_reassembly_feature_handoff_node) = {
    .name = "ip4-reass-feature-hoff",
    .vector_size = sizeof (u32),
    .n_errors = ARRAY_LEN(ip4_reassembly_handoff_error_strings),
    .error_strings = ip4_reassembly_handoff_error_strings,
    .format_trace = format_ip4_reassembly_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:
   */
  