Lookup contexts aka "ACL as a service" {#acl_lookup_context}
======================================

The initial implementation of the ACL plugin had tightly tied the policy (L3-L4) ACLs
to ingress/egress processing on an interface.

However, some uses outside of pure traffic control have appeared, for example,
ACL-based forwarding, etc. Also, improved algorithms of the ACL lookup
could benefit of the more abstract representation, not coupled to the interfaces.

This describes a way to accommodate these use cases by generalizing the ACL
lookups into "ACL lookup contexts", not tied to specific interfaces, usable
by other portions of the code by utilizing the exports.h header file,
which provides the necessary interface.


Why "lookup contexts" and not "match me an ACL#" ?
================================================

The first reason is the logical grouping of multiple ACLs.

The interface matching code currently allows for matching multiple ACLs
in a 'first-match' fashion. Some other use cases also fall into a similar
pattern: they attempt to match a sequence of ACLs, and the first matched ACL
determines what the outcome is, e.g. where to forward traffic. Thus,
a match never happens on an ACL in isolation, but always on a group of
ACLs.

The second reason is potential optimizations in matching.

A naive match on series of ACLs each represented as a vector of ACEs
does not care about the API level - it could be "match one ACL", or
"match the set of ACLs" - there will be just a simple loop iterating over
the ACLs to match, returning the first match. Be it in the ACL code or
in the user code.

However, for more involved lookup methods, providing a more high-level
interface of matching over the entire group of ACLs allows for future
improvements in the algorithms, delivered at once to all the users
of the API.

What is a "lookup context" ?
============================

An ACL lookup context is an entity that groups the set of ACL#s
together for the purposes of a first-match lookup, and may store
additional internal information needed to optimize the lookups
for that particular vector of ACLs.

Using ACL contexts in your code
===============================

In order to use the ACL lookup contexts, you need to include
plugins/acl/exports.h into your code. This header includes
all the necessary dependencies required.

As you probably will invoke this code from another plugin,
the non-inline function calls are implemented via function pointers,
which you need to initialize by calling acl_plugin_exports_init(&acl_plugin), which,
if everything succeeds, returns 0 and fills in the acl_plugin structure
with pointers to the exported methods - else it will return clib_error_t with
more information about what went wrong.

When you have initialized the symbols, you also need to register yourself
as a user of the ACL lookups - this allows to track the ACL lookup context
ownership, as well as make the debug show outputs more user friendly.

To do that, call acl_plugin.register_user_module(caller_module_string, val1_label, val2_label) -
and record the returned value. This will bethe first parameter that you pass to create a new
lookup context. The passed strings must be static, and are used as descriptions for the ACL
contexts themselves, as well as labels for up to two user-supplied u32 labels, used to
differentiate the lookup contexts for the debugging purposes.

Creating a new context is done by calling acl_plugin.get_lookup_context_index(user_id, val1, val2).
The first argument is your "user" ID obtained in a registration call earlier, the other two
arguments are u32s with semantics that you designate. They are used purely for debugging purposes
in the "show acl lookup context" command.

To set the vector of ACL numbers to be looked up within the context, use the function
acl_plugin.set_acl_vec_for_context(lc_index, acl_list). The first parameter specifies the context
that you have created, the second parameter is a vector of u32s, each u32 being the index of the ACL
which we should be looking up within this context. The command is idempotent, i.e.
it unapplies the previously applied list of ACLs, and then sets the new list of ACLs.

Subsequent ACL updates for the already applied ACLs will cause the re-application
on an as-needed basis. Note, that the ACL application is potentially a relatively costly operation,
so it is only expected that these changes will be done in the control plane, NOT in the datapath.

The matching within the context is done using two functions - acl_plugin.fill_5tuple() and
acl_plugin.match_5tuple() and their corresponding inline versions, named acl_plugin_fill_5tuple_inline()
and acl_plugin_match_5tuple_inline(). The inline and non-inline versions have the equivalent functionality,
in that the non-inline version calls the inline version. These two variants are provided
for debugging/maintenance reasons.

When you no longer need a particular context, you can return the allocated resources by calling
acl_plugin.put_lookup_context_index() to mark it as free. The lookup structured associated with
the vector of ACLs set for the lookup are cleaned up automatically. However, the ACLs themselves
are not deleted and are available for subsequent reuse by other lookup contexts if needed.

There is one delicate detail that you might want to be aware of.
When the non-inline functions reference the inline functions,
they are compiled as part of ACL plugin; whereas when you refer to the inline
functions from your code, they are compiled as part of your code.
This makes referring to a single acl_main structure a little trickier.

It is done by having a static p_acl_main within the .h file, 
which points to acl_main of the 
/*
 * Copyright (c) 2015 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.
 */
/*
 * buffer.h: VLIB buffers
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef included_vlib_buffer_h
#define included_vlib_buffer_h

#include <vppinfra/types.h>
#include <vppinfra/cache.h>
#include <vppinfra/serialize.h>
#include <vppinfra/vector.h>
#include <vppinfra/lock.h>
#include <vlib/error.h>		/* for vlib_error_t */

#include <vlib/config.h>	/* for __PRE_DATA_SIZE */
#define VLIB_BUFFER_DATA_SIZE		(2048)
#define VLIB_BUFFER_PRE_DATA_SIZE	__PRE_DATA_SIZE

typedef u8 vlib_buffer_free_list_index_t;

/** \file
    vlib buffer structure definition and a few select
    access methods. This structure and the buffer allocation
    mechanism should perhaps live in vnet, but it would take a lot
    of typing to make it so.
*/

/**
 * Buffer Flags
 */
#define foreach_vlib_buffer_flag \
  _( 0, NON_DEFAULT_FREELIST, "non-default-fl")		\
  _( 1, IS_TRACED, 0)					\
  _( 2, NEXT_PRESENT, 0)				\
  _( 3, TOTAL_LENGTH_VALID, 0)				\
  _( 4, EXT_HDR_VALID, "ext-hdr-valid")

/* NOTE: only buffer generic flags should be defined here, please consider
   using user flags. i.e. src/vnet/buffer.h */

enum
{
#define _(bit, name, v) VLIB_BUFFER_##name  = (1 << (bit)),
  foreach_vlib_buffer_flag
#undef _
};

enum
{
#define _(bit, name, v) VLIB_BUFFER_LOG2_##name  = (bit),
  foreach_vlib_buffer_flag
#undef _
};

  /* User defined buffer flags. */
#define LOG2_VLIB_BUFFER_FLAG_USER(n) (32 - (n))
#define VLIB_BUFFER_FLAG_USER(n) (1 << LOG2_VLIB_BUFFER_FLAG_USER(n))

/* VLIB buffer representation. */
typedef struct
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  STRUCT_MARK (template_start);
  /* Offset within data[] that we are currently processing.
     If negative current header points into predata area. */
  i16 current_data;  /**< signed offset in data[], pre_data[]
                        that we are currently processing.
                        If negative current header points into predata area.
                     */
  u16 current_length;  /**< Nbytes between current data and
                          the end of this buffer.
                       */
  u32 flags; /**< buffer flags:
                <br> VLIB_BUFFER_FREE_LIST_INDEX_MASK: bits used to store free list index,
                <br> VLIB_BUFFER_IS_TRACED: trace this buffer.
                <br> VLIB_BUFFER_NEXT_PRESENT: this is a multi-chunk buffer.
                <br> VLIB_BUFFER_TOTAL_LENGTH_VALID: as it says
                <br> VLIB_BUFFER_EXT_HDR_VALID: buffer contains valid external buffer manager header,
                set to avoid adding it to a flow report
                <br> VLIB_BUFFER_FLAG_USER(n): user-defined bit N
             */

  u32 flow_id;	/**< Generic flow identifier */


  u32 next_buffer;   /**< Next buffer for this linked-list of buffers.
                        Only valid if VLIB_BUFFER_NEXT_PRESENT flag is set.
                     */

    STRUCT_MARK (template_end);

  u32 current_config_index; /**< Used by feature subgraph arcs to
                               visit enabled feature nodes
                            */
  vlib_error_t error;	/**< Error code for buffers to be enqueued
                           to error handler.
                        */
  u8 n_add_refs; /**< Number of additional references to this buffer. */

  u8 buffer_pool_index;	/**< index of buffer pool this buffer belongs. */

  u32 opaque[10]; /**< Opaque data used by sub-graphs for their own purposes.
                    See .../vnet/vnet/buffer.h
                 */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);

  u32 trace_index; /**< Specifies index into trace buffer
                      if VLIB_PACKET_IS_TRACED flag is set.
                   */
  u32 recycle_count; /**< Used by L2 path recycle code */

  u32 total_length_not_including_first_buffer;
  /**< Only valid for first buffer in chain. Current length plus
     total length given here give total number of bytes in buffer chain.
  */
  vlib_buffer_free_list_index_t free_list_index; /** < only used if
						   VLIB_BUFFER_NON_DEFAULT_FREELIST
						   flag is set */
  u8 align_pad[3]; /**< available */
  u32 opaque2[12];  /**< More opaque data, see ../vnet/vnet/buffer.h */

  /***** end of second cache line */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline2);
  u8 pre_data[VLIB_BUFFER_PRE_DATA_SIZE];  /**< Space for inserting data
                                               before buffer start.
                                               Packet rewrite string will be
                                               rewritten backwards and may extend
                                               back before buffer->data[0].
                                               Must come directly before packet data.
                                            */

  u8 data[0]; /**< Packet data. Hardware DMA here */
} vlib_buffer_t;		/* Must be a multiple of 64B. */

#define VLIB_BUFFER_HDR_SIZE  (sizeof(vlib_buffer_t) - VLIB_BUFFER_PRE_DATA_SIZE)

/** \brief Prefetch buffer metadata.
    The first 64 bytes of buffer contains most header information

    @param b - (vlib_buffer_t *) pointer to the buffer
    @param type - LOAD, STORE. In most cases, STORE is the right answer
*/

#define vlib_prefetch_buffer_header(b,type) CLIB_PREFETCH (b, 64, type)

always_inline void
vlib_buffer_struct_is_sane (vlib_buffer_t * b)
{
  ASSERT (sizeof (b[0]) % 64 == 0);

  /* Rewrite data must be before and contiguous with packet data. */
  ASSERT (b->pre_data + VLIB_BUFFER_PRE_DATA_SIZE == b->data);
}

always_inline uword
vlib_buffer_get_va (vlib_buffer_t * b)
{
  return pointer_to_uword (b->data);
}

/** \brief Get pointer to current data to process

    @param b - (vlib_buffer_t *) pointer to the buffer
    @return - (void *) (b->data + b->current_data)
*/

always_inline void *
vlib_buffer_get_current (vlib_buffer_t * b)
{
  /* Check bounds. */
  ASSERT ((signed) b->current_data >= (signed) -VLIB_BUFFER_PRE_DATA_SIZE);
  return b->data + b->current_data;
}

always_inline uword
vlib_buffer_get_current_va (vlib_buffer_t * b)
{
  return vlib_buffer_get_va (b) + b->current_data;
}

/** \brief Advance current data pointer by the supplied (signed!) amount

    @param b - (vlib_buffer_t *) pointer to the buffer
    @param l - (word) signed increment
*/
always_inline void
vlib_buffer_advance (vlib_buffer_t * b, word l)
{
  ASSERT (b->current_length >= l);
  b->current_data += l;
  b->current_length -= l;
}

/** \brief Check if there is enough space in buffer to advance

    @param b - (vlib_buffer_t *) pointer to the buffer
    @param l - (word) size to check
    @return - 0 if there is less space than 'l' in buffer
*/
always_inline u8
vlib_buffer_has_space (vlib_buffer_t * b, word l)
{
  return b->current_length >= l;
}

/** \brief Reset current header & length to state they were in when
    packet was received.

    @param b - (vlib_buffer_t *) pointer to the buffer
*/

always_inline void
vlib_buffer_reset (vlib_buffer_t * b)
{
  b->current_length += clib_max (b->current_data, 0);
  b->current_data = 0;
}

/** \brief Get pointer to buffer's opaque data array

    @param b - (vlib_buffer_t *) pointer to the buffer
    @return - (void *) b->opaque
*/
always_inline void *
vlib_get_buffer_opaque (vlib_buffer_t * b)
{
  return (void *) b->opaque;
}

/** \brief Get pointer to buffer's opaque2 data array

    @param b - (vlib_buffer_t *) pointer to the buffer
    @return - (void *) b->opaque2
*/
always_inline void *
vlib_get_buffer_opaque2 (vlib_buffer_t * b)
{
  return (void *) b->opaque2;
}

/** \brief Get pointer to the end of buffer's data
 * @param b     pointer to the buffer
 * @return      pointer to tail of packet's data
 */
always_inline u8 *
vlib_buffer_get_tail (vlib_buffer_t * b)
{
  return b->data + b->current_data + b->current_length;
}

/** \brief Append uninitialized data to buffer
 * @param b     pointer to the buffer
 * @param size  number of uninitialized bytes
 * @return      pointer to beginning of uninitialized data
 */
always_inline void *
vlib_buffer_put_uninit (vlib_buffer_t * b, u8 size)
{
  void *p = vlib_buffer_get_tail (b);
  /* XXX make sure there's enough space */
  b->current_length += size;
  return p;
}

/** \brief Prepend uninitialized data to buffer
 * @param b     pointer to the buffer
 * @param size  number of uninitialized bytes
 * @return      pointer to beginning of uninitialized data
 */
always_inline void *
vlib_buffer_push_uninit (vlib_buffer_t * b, u8 size)
{
  ASSERT (b->current_data + VLIB_BUFFER_PRE_DATA_SIZE >= size);
  b->current_data -= size;
  b->current_length += size;

  return vlib_buffer_get_current (b);
}

/** \brief Make head room, typically for packet headers
 * @param b     pointer to the buffer
 * @param size  number of head room bytes
 * @return      pointer to start of buffer (current data)
 */
always_inline void *
vlib_buffer_make_headroom (vlib_buffer_t * b, u8 size)
{
  ASSERT (b->current_data + VLIB_BUFFER_PRE_DATA_SIZE >= size);
  b->current_data += size;
  return vlib_buffer_get_current (b);
}

/** \brief Retrieve bytes from buffer head
 * @param b     pointer to the buffer
 * @param size  number of bytes to pull
 * @return      pointer to start of buffer (current data)
 */
always_inline void *
vlib_buffer_pull (vlib_buffer_t * b, u8 size)
{
  if (b->current_length + VLIB_BUFFER_PRE_DATA_SIZE < size)
    return 0;

  void *data = vlib_buffer_get_current (b);
  vlib_buffer_advance (b, size);
  return data;
}

/* Forward declaration. */
struct vlib_main_t;

typedef struct vlib_buffer_free_list_t
{
  /* Template buffer used to initialize first 16 bytes of buffers
     allocated on this free list. */
  vlib_buffer_t buffer_init_template;

  /* Our index into vlib_main_t's buffer_free_list_pool. */
  vlib_buffer_free_list_index_t index;

  /* Number of data bytes for buffers in this free list. */
  u32 n_data_bytes;

  /* Number of buffers to allocate when we need to allocate new buffers */
  u32 min_n_buffers_each_alloc;

  /* Total number of buffers allocated from this free list. */
  u32 n_alloc;

  /* Vector of free buffers.  Each element is a byte offset into I/O heap. */
  u32 *buffers;

  /* index of buffer pool used to get / put buffers */
  u8 buffer_pool_index;

  /* Free list name. */
  u8 *name;

  /* Callback functions to initialize newly allocated buffers.
     If null buffers are zeroed. */
  void (*buffer_init_function) (struct vlib_main_t * vm,
				struct vlib_buffer_free_list_t * fl,
				u32 * buffers, u32 n_buffers);

  uword buffer_init_function_opaque;
} __attribute__ ((aligned (16))) vlib_buffer_free_list_t;

typedef uword (vlib_buffer_fill_free_list_cb_t) (struct vlib_main_t * vm,
						 vlib_buffer_free_list_t * fl,
						 uword min_free_buffers);
typedef void (vlib_buffer_free_cb_t) (struct vlib_main_t * vm, u32 * buffers,
				      u32 n_buffers);
typedef void (vlib_buffer_free_no_next_cb_t) (struct vlib_main_t * vm,
					      u32 * buffers, u32 n_buffers);

typedef struct
{
  vlib_buffer_fill_free_list_cb_t *vlib_buffer_fill_free_list_cb;
  vlib_buffer_free_cb_t *vlib_buffer_free_cb;
  vlib_buffer_free_no_next_cb_t *vlib_buffer_free_no_next_cb;
  void (*vlib_packet_template_init_cb) (struct vlib_main_t * vm, void *t,
					void *packet_data,
					uword n_packet_data_bytes,
					uword
					min_n_buffers_each_physmem_alloc,
					u8 * name);
  void (*vlib_buffer_delete_free_list_cb) (struct vlib_main_t * vm,
					   vlib_buffer_free_list_index_t
					   free_list_index);
} vlib_buffer_callbacks_t;

extern vlib_buffer_callbacks_t *vlib_buffer_callbacks;

typedef struct
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  uword start;
  uword size;
  uword log2_page_size;
  u32 physmem_map_index;
  u32 buffer_size;
  u32 *buffers;
  clib_spinlock_t lock;
} vlib_buffer_pool_t;

typedef struct
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  /* Virtual memory address and size of buffer memory, used for calculating
     buffer index */
  uword buffer_mem_start;
  uword buffer_mem_size;
  vlib_buffer_pool_t *buffer_pools;

  /* Buffer free callback, for subversive activities */
    u32 (*buffer_free_callback) (struct vlib_main_t * vm,
				 u32 * buffers,
				 u32 n_buffers, u32 follow_buffer_next);
#define VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX (0)
#define VLIB_BUFFER_DEFAULT_FREE_LIST_BYTES VLIB_BUFFER_DATA_SIZE

  /* Hash table mapping buffer size (rounded to next unit of
     sizeof (vlib_buffer_t)) to free list index. */
  uword *free_list_by_size;

  /* Hash table mapping buffer index into number
     0 => allocated but free, 1 => allocated and not-free.
     If buffer index is not in hash table then this buffer
     has never been allocated. */
  uword *buffer_known_hash;
  clib_spinlock_t buffer_known_hash_lockp;

  /* Callbacks */
  vlib_buffer_callbacks_t cb;
  int callbacks_registered;
} vlib_buffer_main_t;

extern vlib_buffer_main_t buffer_main;

static_always_inline vlib_buffer_pool_t *
vlib_buffer_pool_get (u8 buffer_pool_index)
{
  vlib_buffer_main_t *bm = &buffer_main;
  return vec_elt_at_index (bm->buffer_pools, buffer_pool_index);
}

u8 vlib_buffer_register_physmem_map (struct vlib_main_t * vm,
				     u32 physmem_map_index);

clib_error_t *vlib_buffer_main_init (struct vlib_main_t *vm);

typedef struct
{
  struct vlib_main_t *vlib_main;

  u32 first_buffer, last_buffer;

  union
  {
    struct
    {
      /* Total accumulated bytes in chain starting with first_buffer. */
      u32 n_total_data_bytes;

      /* Max number of bytes to accumulate in chain starting with first_buffer.
         As this limit is reached buffers are enqueued to next node. */
      u32 max_n_data_bytes_per_chain;

      /* Next node to enqueue buffers to relative to current process node. */
      u32 next_index;

      /* Free list to use to allocate new buffers. */
      vlib_buffer_free_list_index_t free_list_index;
    } tx;

    struct
    {
      /* CLIB fifo of buffer indices waiting to be unserialized. */
      u32 *buffer_fifo;

      /* Event type used to signal that RX buffers have been added to fifo. */
      uword ready_one_time_event;
    } rx;
  };
} vlib_serialize_buffer_main_t;

void serialize_open_vlib_buffer (serialize_main_t * m, struct vlib_main_t *vm,
				 vlib_serialize_buffer_main_t * sm);
void unserialize_open_vlib_buffer (serialize_main_t * m,
				   struct vlib_main_t *vm,
				   vlib_serialize_buffer_main_t * sm);

u32 serialize_close_vlib_buffer (serialize_main_t * m);
void unserialize_close_vlib_buffer (serialize_main_t * m);
void *vlib_set_buffer_free_callback (struct vlib_main_t *vm, void *fp);

always_inline u32
serialize_vlib_buffer_n_bytes (serialize_main_t * m)
{
  serialize_stream_t *s = &m->stream;
  vlib_serialize_buffer_main_t *sm
    = uword_to_pointer (m->stream.data_function_opaque,
			vlib_serialize_buffer_main_t *);
  return sm->tx.n_total_data_bytes + s->current_buffer_index +
    vec_len (s->overflow_buffer);
}

/*
 */

/** \brief Compile time buffer trajectory tracing option
    Turn this on if you run into "bad monkey" contexts,
    and you want to know exactly which nodes they've visited...
    See vlib/main.c...
*/
#define VLIB_BUFFER_TRACE_TRAJECTORY 0

#if VLIB_BUFFER_TRACE_TRAJECTORY > 0
extern void (*vlib_buffer_trace_trajectory_cb) (vlib_buffer_t * b, u32 index);
extern void (*vlib_buffer_trace_trajectory_init_cb) (vlib_buffer_t * b);
extern void vlib_buffer_trace_trajectory_init (vlib_buffer_t * b);
#define VLIB_BUFFER_TRACE_TRAJECTORY_INIT(b) \
  vlib_buffer_trace_trajectory_init (b);
#else
#define VLIB_BUFFER_TRACE_TRAJECTORY_INIT(b)
#endif /* VLIB_BUFFER_TRACE_TRAJECTORY */

#endif /* included_vlib_buffer_h */

#define VLIB_BUFFER_REGISTER_CALLBACKS(x,...)                           \
    __VA_ARGS__ vlib_buffer_callbacks_t __##x##_buffer_callbacks;       \
static void __vlib_add_buffer_callbacks_t_##x (void)                    \
    __attribute__((__constructor__)) ;                                  \
static void __vlib_add_buffer_callbacks_t_##x (void)                    \
{                                                                       \
    if (vlib_buffer_callbacks)                                          \
      clib_panic ("vlib buffer callbacks already registered");          \
    vlib_buffer_callbacks = &__##x##_buffer_callbacks;                  \
}                                                                       \
static void __vlib_rm_buffer_callbacks_t_##x (void)                     \
    __attribute__((__destructor__)) ;                                   \
static void __vlib_rm_buffer_callbacks_t_##x (void)                     \
{ vlib_buffer_callbacks = 0; }                                          \
__VA_ARGS__ vlib_buffer_callbacks_t __##x##_buffer_callbacks

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