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path: root/src/vnet/ip/reass/ip4_full_reass.c
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.. _vmxnet3:

VPP with VMware/Vmxnet3
=======================

This section describes a native Vmxnet3 driver that is included with VPP.
This driver is written as a plugin and is found in src/plugin/vmxnet3.

Advantages
----------

The native VPP native vmxnet3 driver provides the following features
that are not provided with the standard dpdk vmxnet3 driver.

-  Interrupt mode
-  Adaptive mode
-  LRO/TSO mode

Does not support
----------------

This driver does yet support the following features.

-  VLAN filter

Prerequisites
-------------

-  This code is tested with vfio-pci driver installed with Ubuntu 18.04
   which has kernel version 4.15.0-33-generic.

-  This code is tested with ESXi vSwitch version 6.5 and 6.7 for LRO/TSO support,
   VMware Workstation 15 Pro (no LRO/TSO), and VMware Fusion 11 Pro (no LRO/TSO).

-  Driver requires MSI-X interrupt support, which is not supported by
   uio_pci_generic driver, so vfio-pci needs to be used. On systems
   without IOMMU vfio driver can still be used with recent kernels which
   support no-iommu mode.

VMware Fusion for Mac
---------------------

VMware fusion does not have a menu option to change the default driver (e1000)
to the **vmxnet3** driver. VPP supports the **vmxnet3** driver.

These instructions describe how to change the e1000 driver for VMware fusion.

* From the VMware Fusion menu bar select **Window** then **Virtual Machine
  Library**.
* From the Virtual Machine menu right click on the Virtual Machine you are using
  and select **Show in Finder**
* Find the name associated with the VM you are using, right click on it and
  select **Show Package Contents**
* Find the **.vmx** file and edit it.
* Find all the occurrences of **e1000** and change them to **vmxnet3**

If you are concerned more with configuration not performance the vmxnet3 driver
can be set to **interrupt** mode in VPP. This will save a great deal on battery
usage. Do this with the following

VMware Workstatiom PRO 15 for Linux
-----------------------------------

VMware Workstation does not have a menu option to change the default driver
(e1000) to the **vmxnet3** driver. VPP supports the **vmxnet3** driver.

These instructions describe how to change the e1000 driver for VMware
Workstation PRO 15 Linux. You may need to be a superuser for performing these
steps.

* Shut down the VM you are about to change.
* From the vmware folder where vmware creates and stores the VM's, change the
  directory to the specific VM which you want to modify, and use your favorite
  text editor to open the corresponding VM's .vmx file. By default, it is
  $HOME/vmware/<vm-name>/<vm-name>.vmx
* Locate the line for the interface which you want to modify. For example, if it
  is ethernet1, then change the line **ethernet1.virtualDev = "e1000"** to
  **ethernet1.virtualDev = "vmxnet3"**
* Save the file and power on the VM.

If you are concerned more with configuration not performance the vmxnet3 driver
can be set to **interrupt** mode in VPP. This will save a great deal on battery
usage. Do this with the following

.. code-block:: console

    $ sudo vppctl set interface rx-mode <interface> interrupt


System setup
~~~~~~~~~~~~

To use the native VPP vmxnet3 driver use the following Steps

Load VFIO driver

.. code-block:: console

    $ sudo modprobe vfio-pci

Make sure the interface is down

.. code-block:: console

    $ sudo ifconfig <if-name> down

The next 2 steps are optional and may be accomplished by specifying the optional
"bind" keyword when creating the vmxnet3 interface.

For systems without IOMMU only, enable unsafe NOIOMMU mode

.. code-block:: console

    $ echo Y | sudo tee /sys/module/vfio/parameters/enable_unsafe_noiommu_mode

To bind interface to vfio-pci first install the :ref:`configutil`. This will
download the dpdk_devbind.py script. It is located in
*/usr/vpp/vpp-config/scripts* with Centos and
*/usr/local/vpp/vpp-config/scripts* with Ubuntu.

Bind the driver with the following commands:

.. code-block:: console

    $ sudo /usr/local/vpp/vpp-config/scripts/dpdk-devbind.py -s

    Network devices using DPDK-compatible driver
    ============================================
    <none>
    
    Network devices using kernel driver
    ===================================
    0000:03:00.0 'VMXNET3 Ethernet Controller' if=ens160 drv=vmxnet3 unused=vfio-pci,uio_pci_generic 
    0000:0b:00.0 'VMXNET3 Ethernet Controller' drv=vfio-pci unused=vmxnet3,uio_pci_generic
    0000:13:00.0 'VMXNET3 Ethernet Controller' drv=vfio-pci unused=vmxnet3,uio_pci_generic
    .....

    $ sudo /usr/local/vpp/vpp-config/scripts/dpdk-devbind.py --bind vfio-pci 0b:00.0


Interface Creation
~~~~~~~~~~~~~~~~~~

Now create the interface dynamically with following. The bind option must be
specified if pci is not already bound manually by above steps.

.. code-block:: console

    $ sudo vppctl create interface vmxnet3 0000:0b:00.0 bind
    $ sudo vppctl set interface state vmxnet3-0/b/0/0 up

Interface Deletion
~~~~~~~~~~~~~~~~~~

If the interface needs to be deleted:

.. code-block:: console

    $ sudo vppctl delete interface vmxnet3 <if-name>

Show vmxnet3
~~~~~~~~~~~~

Interface and ring information can be obtained with the command
**show vmxnet3 [if-name] [desc]**

For example:

.. code-block:: console

    $ sudo vppctl show vmxnet3
    Interface: vmxnet3-0/b/0/0 (ifindex 1)
      Version: 1
      PCI Address: 0000:0b:00.0
      Mac Address: 00:50:56:88:63:be
      hw if index: 1
      Device instance: 0
      Number of interrupts: 2
      Queue 0 (RX)
        RX completion next index 786
        RX completion generation flag 0x80000000
        ring 0 size 4096 fill 4094 consume 785 produce 784
        ring 1 size 4096 fill 4096 consume 0 produce 0
      Queue 0 (TX)
        TX completion next index 216
        TX completion generation flag 0x0
        size 4096 consume 216 produce 245
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/*
 * 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;

  // reference count for enabling/disabling feature - per interface
  u32 *feature_use_refcount_per_intf;
} 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;
  bool is_after_handoff;
  ip4_header_t ip4_header;
} 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)
    {
      if (t->is_after_handoff)
	{
	  s =
	    format (s, "%U\n", format_ip4_header, &t->ip4_header,
		    sizeof (t->ip4_header));
	  indent = 2;
	}
      s =
	format (s, "%Ureass id: %u, op id: %u, ", format_white_space, indent,
		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);
  bool is_after_handoff = false;
  if (vlib_buffer_get_trace_thread (b) != vm->thread_index)
    {
      is_after_handoff = true;
    }
  ip4_full_reass_trace_t *t = vlib_add_trace (vm, node, b, sizeof (t[0]));
  t->is_after_handoff = is_after_handoff;
  if (t->is_after_handoff)
    {
      clib_memcpy (&t->ip4_header, vlib_buffer_get_current (b),
		   clib_min (sizeof (t->ip4_header), b->current_length));
    }
  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;
      int handoff =
	reass->memory_owner_thread_index != 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 && handoff)
	{
	  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;
	      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);
		  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:

	  if (bi0 != ~0)
	    {
	      to_next[0] = bi0;
	      to_next += 1;
	      n_left_to_next -= 1;

	      /* bi0 might have been updated by reass_finalize, reload */
	      b0 = vlib_get_buffer (vm, bi0);
	      b0->error = node->errors[error0];

	      if (next0 == IP4_FULL_REASS_NEXT_HANDOFF)
		{
		  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
		    {
		      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)
		{
		  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);

  rm->feature_use_refcount_per_intf = NULL;
  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] = 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* */

#ifndef CLIB_MARCH_VARIANT
int
ip4_full_reass_enable_disable_with_refcnt (u32 sw_if_index, int is_enable)
{
  ip4_full_reass_main_t *rm = &ip4_full_reass_main;
  vec_validate (rm->feature_use_refcount_per_intf, sw_if_index);
  if (is_enable)
    {
      if (!rm->feature_use_refcount_per_intf[sw_if_index])
	{
	  ++rm->feature_use_refcount_per_intf[sw_if_index];
	  return vnet_feature_enable_disable ("ip4-unicast",
					      "ip4-full-reassembly-feature",
					      sw_if_index, 1, 0, 0);
	}
      ++rm->feature_use_refcount_per_intf[sw_if_index];
    }
  else
    {
      --rm->feature_use_refcount_per_intf[sw_if_index];
      if (!rm->feature_use_refcount_per_intf[sw_if_index])
	return vnet_feature_enable_disable ("ip4-unicast",
					    "ip4-full-reassembly-feature",
					    sw_if_index, 0, 0, 0);
    }
  return -1;
}
#endif

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */