gbp_learn_node.c

Go to the documentation of this file.

/*
 * Copyright (c) 2018 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#include <plugins/gbp/gbp.h>
#include <plugins/gbp/gbp_learn.h>
#include <plugins/gbp/gbp_bridge_domain.h>
#include <vlibmemory/api.h>
 
#include <vnet/util/throttle.h>
#include <vnet/l2/l2_input.h>
#include <vnet/fib/fib_table.h>
#include <vnet/vxlan-gbp/vxlan_gbp_packet.h>
#include <vnet/ethernet/arp_packet.h>
 
#define GBP_LEARN_DBG(...)                                      \
    vlib_log_debug (gbp_learn_main.gl_logger, __VA_ARGS__);
 
#define foreach_gbp_learn                      \
  _(DROP,    "drop")
 
typedef enum
{
#define _(sym,str) GBP_LEARN_ERROR_##sym,
  foreach_gbp_learn
#undef _
    GBP_LEARN_N_ERROR,
} gbp_learn_error_t;
 
static char *gbp_learn_error_strings[] = {
#define _(sym,string) string,
  foreach_gbp_learn
#undef _
};
 
typedef enum
{
#define _(sym,str) GBP_LEARN_NEXT_##sym,
  foreach_gbp_learn
#undef _
    GBP_LEARN_N_NEXT,
} gbp_learn_next_t;
 
typedef struct gbp_learn_l2_t_
{
  ip46_address_t ip;
  mac_address_t mac;
  u32 sw_if_index;
  u32 bd_index;
  sclass_t sclass;
  ip46_address_t outer_src;
  ip46_address_t outer_dst;
} gbp_learn_l2_t;
 
 
static void
gbp_learn_l2_cp (const gbp_learn_l2_t * gl2)
{
  ip46_address_t *ips = NULL;
 
  GBP_LEARN_DBG ("L2 EP: %U %U, %d",
                 format_mac_address_t, &gl2->mac,
                 format_ip46_address, &gl2->ip, IP46_TYPE_ANY, gl2->sclass);
 
  if (!ip46_address_is_zero (&gl2->ip))
    vec_add1 (ips, gl2->ip);
 
  /*
   * flip the source and dst, since that's how it was received, this API
   * takes how it's sent
   */
  gbp_endpoint_update_and_lock (GBP_ENDPOINT_SRC_DP,
                                gl2->sw_if_index, ips,
                                &gl2->mac, INDEX_INVALID,
                                INDEX_INVALID, gl2->sclass,
                                (GBP_ENDPOINT_FLAG_LEARNT |
                                 GBP_ENDPOINT_FLAG_REMOTE),
                                &gl2->outer_dst, &gl2->outer_src, NULL);
  vec_free (ips);
}
 
static void
gbp_learn_l2_ip4_dp (const u8 * mac, const ip4_address_t * ip,
                     u32 bd_index, u32 sw_if_index, sclass_t sclass,
                     const ip4_address_t * outer_src,
                     const ip4_address_t * outer_dst)
{
  gbp_learn_l2_t gl2 = {
    .sw_if_index = sw_if_index,
    .bd_index = bd_index,
    .sclass = sclass,
    .ip.ip4 = *ip,
    .outer_src.ip4 = *outer_src,
    .outer_dst.ip4 = *outer_dst,
  };
  mac_address_from_bytes (&gl2.mac, mac);
 
  vl_api_rpc_call_main_thread (gbp_learn_l2_cp, (u8 *) & gl2, sizeof (gl2));
}
 
static void
gbp_learn_l2_ip6_dp (const u8 * mac, const ip6_address_t * ip,
                     u32 bd_index, u32 sw_if_index, sclass_t sclass,
                     const ip4_address_t * outer_src,
                     const ip4_address_t * outer_dst)
{
  gbp_learn_l2_t gl2 = {
    .sw_if_index = sw_if_index,
    .bd_index = bd_index,
    .sclass = sclass,
    .ip.ip6 = *ip,
    .outer_src.ip4 = *outer_src,
    .outer_dst.ip4 = *outer_dst,
  };
  mac_address_from_bytes (&gl2.mac, mac);
 
  vl_api_rpc_call_main_thread (gbp_learn_l2_cp, (u8 *) & gl2, sizeof (gl2));
}
 
static void
gbp_learn_l2_dp (const u8 * mac, u32 bd_index, u32 sw_if_index,
                 sclass_t sclass,
                 const ip4_address_t * outer_src,
                 const ip4_address_t * outer_dst)
{
  gbp_learn_l2_t gl2 = {
    .sw_if_index = sw_if_index,
    .bd_index = bd_index,
    .sclass = sclass,
    .outer_src.ip4 = *outer_src,
    .outer_dst.ip4 = *outer_dst,
  };
  mac_address_from_bytes (&gl2.mac, mac);
 
  vl_api_rpc_call_main_thread (gbp_learn_l2_cp, (u8 *) & gl2, sizeof (gl2));
}
 
/**
 * per-packet trace data
 */
typedef struct gbp_learn_l2_trace_t_
{
  /* per-pkt trace data */
  mac_address_t mac;
  u32 sw_if_index;
  u32 new;
  u32 throttled;
  u32 sclass;
  u32 d_bit;
  gbp_bridge_domain_flags_t gb_flags;
} gbp_learn_l2_trace_t;
 
always_inline void
gbp_learn_get_outer (const ethernet_header_t * eh0,
                     ip4_address_t * outer_src, ip4_address_t * outer_dst)
{
  ip4_header_t *ip0;
  u8 *buff;
 
  /* rewind back to the ivxlan header */
  buff = (u8 *) eh0;
  buff -= (sizeof (vxlan_gbp_header_t) +
           sizeof (udp_header_t) + sizeof (ip4_header_t));
 
  ip0 = (ip4_header_t *) buff;
 
  *outer_src = ip0->src_address;
  *outer_dst = ip0->dst_address;
}
 
always_inline int
gbp_endpoint_update_required (const gbp_endpoint_t * ge0,
                              u32 rx_sw_if_index, sclass_t sclass)
{
  /* Conditions for [re]learning this EP */
 
  /* 1. it doesn't have a dataplane source */
  if (!gbp_endpoint_is_learnt (ge0))
    return (!0);
 
  /* 2. has the input interface changed */
  if (gbp_itf_get_sw_if_index (ge0->ge_fwd.gef_itf) != rx_sw_if_index)
    return (!0);
 
  /* 3. has the sclass changed */
  if (sclass != ge0->ge_fwd.gef_sclass)
    return (!0);
 
  /* otherwise it's unchanged */
  return (0);
}
 
VLIB_NODE_FN (gbp_learn_l2_node) (vlib_main_t * vm,
                                  vlib_node_runtime_t * node,
                                  vlib_frame_t * frame)
{
  u32 n_left_from, *from, *to_next, next_index, thread_index, seed;
  gbp_learn_main_t *glm;
  f64 time_now;
 
  glm = &gbp_learn_main;
  next_index = 0;
  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);
  time_now = vlib_time_now (vm);
  thread_index = vm->thread_index;
 
  seed = throttle_seed (&glm->gl_l2_throttle, thread_index, time_now);
 
  while (n_left_from > 0)
    {
      u32 n_left_to_next;
 
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          ip4_address_t outer_src, outer_dst;
          const ethernet_header_t *eh0;
          u32 bi0, sw_if_index0, t0;
          gbp_bridge_domain_t *gb0;
          gbp_learn_next_t next0;
          gbp_endpoint_t *ge0;
          vlib_buffer_t *b0;
          sclass_t sclass0;
 
          next0 = GBP_LEARN_NEXT_DROP;
          bi0 = from[0];
          to_next[0] = bi0;
          from += 1;
          to_next += 1;
          n_left_from -= 1;
          n_left_to_next -= 1;
 
          b0 = vlib_get_buffer (vm, bi0);
          sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 
          eh0 = vlib_buffer_get_current (b0);
          sclass0 = vnet_buffer2 (b0)->gbp.sclass;
 
          next0 = vnet_l2_feature_next (b0, glm->gl_l2_input_feat_next,
                                        L2INPUT_FEAT_GBP_LEARN);
 
          ge0 = gbp_endpoint_find_mac (eh0->src_address,
                                       vnet_buffer (b0)->l2.bd_index);
          gb0 =
            gbp_bridge_domain_get_by_bd_index (vnet_buffer (b0)->l2.bd_index);
 
          if ((vnet_buffer2 (b0)->gbp.flags & VXLAN_GBP_GPFLAGS_D) ||
              (gb0->gb_flags & GBP_BD_FLAG_DO_NOT_LEARN))
            {
              t0 = 1;
              goto trace;
            }
 
          /*
           * check for new EP or a moved EP
           */
          if (NULL == ge0 ||
              gbp_endpoint_update_required (ge0, sw_if_index0, sclass0))
            {
              /*
               * use the last 4 bytes of the mac address as the hash for the EP
               */
              t0 = throttle_check (&glm->gl_l2_throttle, thread_index,
                                   *((u32 *) (eh0->src_address + 2)), seed);
              if (!t0)
                {
                  gbp_learn_get_outer (eh0, &outer_src, &outer_dst);
 
                  if (outer_src.as_u32 == 0 || outer_dst.as_u32 == 0)
                    {
                      t0 = 2;
                      goto trace;
                    }
 
                  switch (clib_net_to_host_u16 (eh0->type))
                    {
                    case ETHERNET_TYPE_IP4:
                      {
                        const ip4_header_t *ip0;
 
                        ip0 = (ip4_header_t *) (eh0 + 1);
 
                        gbp_learn_l2_ip4_dp (eh0->src_address,
                                             &ip0->src_address,
                                             vnet_buffer (b0)->l2.bd_index,
                                             sw_if_index0, sclass0,
                                             &outer_src, &outer_dst);
 
                        break;
                      }
                    case ETHERNET_TYPE_IP6:
                      {
                        const ip6_header_t *ip0;
 
                        ip0 = (ip6_header_t *) (eh0 + 1);
 
                        gbp_learn_l2_ip6_dp (eh0->src_address,
                                             &ip0->src_address,
                                             vnet_buffer (b0)->l2.bd_index,
                                             sw_if_index0, sclass0,
                                             &outer_src, &outer_dst);
 
                        break;
                      }
                    case ETHERNET_TYPE_ARP:
                      {
                        const ethernet_arp_header_t *arp0;
 
                        arp0 = (ethernet_arp_header_t *) (eh0 + 1);
 
                        gbp_learn_l2_ip4_dp (eh0->src_address,
                                             &arp0->ip4_over_ethernet[0].ip4,
                                             vnet_buffer (b0)->l2.bd_index,
                                             sw_if_index0, sclass0,
                                             &outer_src, &outer_dst);
                        break;
                      }
                    default:
                      gbp_learn_l2_dp (eh0->src_address,
                                       vnet_buffer (b0)->l2.bd_index,
                                       sw_if_index0, sclass0,
                                       &outer_src, &outer_dst);
                      break;
                    }
                }
            }
          else
            {
              /*
               * this update could happen simultaneoulsy from multiple workers
               * but that's ok we are not interested in being very accurate.
               */
              t0 = 0;
              ge0->ge_last_time = time_now;
            }
        trace:
          if (PREDICT_FALSE ((b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              gbp_learn_l2_trace_t *t =
                vlib_add_trace (vm, node, b0, sizeof (*t));
              clib_memcpy_fast (t->mac.bytes, eh0->src_address, 6);
              t->new = (NULL == ge0);
              t->throttled = t0;
              t->sw_if_index = sw_if_index0;
              t->sclass = sclass0;
              t->gb_flags = gb0->gb_flags;
              t->d_bit = ! !(vnet_buffer2 (b0)->gbp.flags &
                             VXLAN_GBP_GPFLAGS_D);
            }
 
          /* verify speculative enqueue, maybe switch current next frame */
          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           bi0, next0);
        }
 
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
 
  return frame->n_vectors;
}
 
/* packet trace format function */
static u8 *
format_gbp_learn_l2_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 *);
  gbp_learn_l2_trace_t *t = va_arg (*args, gbp_learn_l2_trace_t *);
 
  s = format (s, "new:%d throttled:%d d-bit:%d mac:%U itf:%d sclass:%d"
              " gb-flags:%U",
              t->new, t->throttled, t->d_bit,
              format_mac_address_t, &t->mac, t->sw_if_index, t->sclass,
              format_gbp_bridge_domain_flags, t->gb_flags);
 
  return s;
}
 
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (gbp_learn_l2_node) = {
  .name = "gbp-learn-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_gbp_learn_l2_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
 
  .n_errors = ARRAY_LEN(gbp_learn_error_strings),
  .error_strings = gbp_learn_error_strings,
 
  .n_next_nodes = GBP_LEARN_N_NEXT,
 
  .next_nodes = {
    [GBP_LEARN_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */
 
typedef struct gbp_learn_l3_t_
{
  ip46_address_t ip;
  u32 fib_index;
  u32 sw_if_index;
  sclass_t sclass;
  ip46_address_t outer_src;
  ip46_address_t outer_dst;
} gbp_learn_l3_t;
 
static void
gbp_learn_l3_cp (const gbp_learn_l3_t * gl3)
{
  ip46_address_t *ips = NULL;
 
  GBP_LEARN_DBG ("L3 EP: %U, %d", format_ip46_address, &gl3->ip,
                 IP46_TYPE_ANY, gl3->sclass);
 
  vec_add1 (ips, gl3->ip);
 
  gbp_endpoint_update_and_lock (GBP_ENDPOINT_SRC_DP,
                                gl3->sw_if_index, ips, NULL,
                                INDEX_INVALID, INDEX_INVALID, gl3->sclass,
                                (GBP_ENDPOINT_FLAG_REMOTE |
                                 GBP_ENDPOINT_FLAG_LEARNT),
                                &gl3->outer_dst, &gl3->outer_src, NULL);
  vec_free (ips);
}
 
static void
gbp_learn_ip4_dp (const ip4_address_t * ip,
                  u32 fib_index, u32 sw_if_index, sclass_t sclass,
                  const ip4_address_t * outer_src,
                  const ip4_address_t * outer_dst)
{
  /* *INDENT-OFF* */
  gbp_learn_l3_t gl3 = {
    .ip = {
      .ip4 = *ip,
    },
    .sw_if_index = sw_if_index,
    .fib_index = fib_index,
    .sclass = sclass,
    .outer_src.ip4 = *outer_src,
    .outer_dst.ip4 = *outer_dst,
  };
  /* *INDENT-ON* */
 
  vl_api_rpc_call_main_thread (gbp_learn_l3_cp, (u8 *) & gl3, sizeof (gl3));
}
 
static void
gbp_learn_ip6_dp (const ip6_address_t * ip,
                  u32 fib_index, u32 sw_if_index, sclass_t sclass,
                  const ip4_address_t * outer_src,
                  const ip4_address_t * outer_dst)
{
  /* *INDENT-OFF* */
  gbp_learn_l3_t gl3 = {
    .ip = {
      .ip6 = *ip,
    },
    .sw_if_index = sw_if_index,
    .fib_index = fib_index,
    .sclass = sclass,
    .outer_src.ip4 = *outer_src,
    .outer_dst.ip4 = *outer_dst,
  };
  /* *INDENT-ON* */
 
  vl_api_rpc_call_main_thread (gbp_learn_l3_cp, (u8 *) & gl3, sizeof (gl3));
}
 
/**
 * per-packet trace data
 */
typedef struct gbp_learn_l3_trace_t_
{
  /* per-pkt trace data */
  ip46_address_t ip;
  u32 sw_if_index;
  u32 new;
  u32 throttled;
  u32 sclass;
} gbp_learn_l3_trace_t;
 
static uword
gbp_learn_l3 (vlib_main_t * vm,
              vlib_node_runtime_t * node, vlib_frame_t * frame,
              fib_protocol_t fproto)
{
  u32 n_left_from, *from, *to_next, next_index, thread_index, seed;
  gbp_learn_main_t *glm;
  f64 time_now;
 
  glm = &gbp_learn_main;
  next_index = 0;
  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);
  time_now = vlib_time_now (vm);
  thread_index = vm->thread_index;
 
  seed = throttle_seed (&glm->gl_l3_throttle, thread_index, time_now);
 
  while (n_left_from > 0)
    {
      u32 n_left_to_next;
 
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          CLIB_UNUSED (const ip4_header_t *) ip4_0;
          CLIB_UNUSED (const ip6_header_t *) ip6_0;
          u32 bi0, sw_if_index0, t0, fib_index0;
          ip4_address_t outer_src, outer_dst;
          ethernet_header_t *eth0;
          gbp_learn_next_t next0;
          gbp_endpoint_t *ge0;
          vlib_buffer_t *b0;
          sclass_t sclass0;
 
          next0 = GBP_LEARN_NEXT_DROP;
          bi0 = from[0];
          to_next[0] = bi0;
          from += 1;
          to_next += 1;
          n_left_from -= 1;
          n_left_to_next -= 1;
 
          b0 = vlib_get_buffer (vm, bi0);
          sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
          sclass0 = vnet_buffer2 (b0)->gbp.sclass;
          ip6_0 = NULL;
          ip4_0 = NULL;
 
          vnet_feature_next (&next0, b0);
 
          if (vnet_buffer2 (b0)->gbp.flags & VXLAN_GBP_GPFLAGS_D)
            {
              t0 = 1;
              ge0 = NULL;
              goto trace;
            }
 
          fib_index0 = fib_table_get_index_for_sw_if_index (fproto,
                                                            sw_if_index0);
 
          if (FIB_PROTOCOL_IP6 == fproto)
            {
              ip6_0 = vlib_buffer_get_current (b0);
              eth0 = (ethernet_header_t *) (((u8 *) ip6_0) - sizeof (*eth0));
 
              gbp_learn_get_outer (eth0, &outer_src, &outer_dst);
 
              ge0 = gbp_endpoint_find_ip6 (&ip6_0->src_address, fib_index0);
 
              if ((NULL == ge0) ||
                  gbp_endpoint_update_required (ge0, sw_if_index0, sclass0))
                {
                  t0 = throttle_check (&glm->gl_l3_throttle,
                                       thread_index,
                                       ip6_address_hash_to_u32
                                       (&ip6_0->src_address), seed);
 
                  if (!t0)
                    {
                      gbp_learn_ip6_dp (&ip6_0->src_address,
                                        fib_index0, sw_if_index0, sclass0,
                                        &outer_src, &outer_dst);
                    }
                }
              else
                {
                  /*
                   * this update could happen simultaneoulsy from multiple
                   * workers but that's ok we are not interested in being
                   * very accurate.
                   */
                  t0 = 0;
                  ge0->ge_last_time = time_now;
                }
            }
          else
            {
              ip4_0 = vlib_buffer_get_current (b0);
              eth0 = (ethernet_header_t *) (((u8 *) ip4_0) - sizeof (*eth0));
 
              gbp_learn_get_outer (eth0, &outer_src, &outer_dst);
              ge0 = gbp_endpoint_find_ip4 (&ip4_0->src_address, fib_index0);
 
              if ((NULL == ge0) ||
                  gbp_endpoint_update_required (ge0, sw_if_index0, sclass0))
                {
                  t0 = throttle_check (&glm->gl_l3_throttle, thread_index,
                                       ip4_0->src_address.as_u32, seed);
 
                  if (!t0)
                    {
                      gbp_learn_ip4_dp (&ip4_0->src_address,
                                        fib_index0, sw_if_index0, sclass0,
                                        &outer_src, &outer_dst);
                    }
                }
              else
                {
                  /*
                   * this update could happen simultaneoulsy from multiple
                   * workers but that's ok we are not interested in being
                   * very accurate.
                   */
                  t0 = 0;
                  ge0->ge_last_time = time_now;
                }
            }
        trace:
          if (PREDICT_FALSE ((b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              gbp_learn_l3_trace_t *t;
 
              t = vlib_add_trace (vm, node, b0, sizeof (*t));
              if (FIB_PROTOCOL_IP6 == fproto && ip6_0)
                ip46_address_set_ip6 (&t->ip, &ip6_0->src_address);
              if (FIB_PROTOCOL_IP4 == fproto && ip4_0)
                ip46_address_set_ip4 (&t->ip, &ip4_0->src_address);
              t->new = (NULL == ge0);
              t->throttled = t0;
              t->sw_if_index = sw_if_index0;
              t->sclass = sclass0;
            }
 
          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           bi0, next0);
        }
 
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
 
  return frame->n_vectors;
}
 
/* packet trace format function */
static u8 *
format_gbp_learn_l3_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 *);
  gbp_learn_l3_trace_t *t = va_arg (*args, gbp_learn_l3_trace_t *);
 
  s = format (s, "new:%d throttled:%d ip:%U itf:%d sclass:%d",
              t->new, t->throttled,
              format_ip46_address, &t->ip, IP46_TYPE_ANY, t->sw_if_index,
              t->sclass);
 
  return s;
}
 
VLIB_NODE_FN (gbp_learn_ip4_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return (gbp_learn_l3 (vm, node, frame, FIB_PROTOCOL_IP4));
}
 
VLIB_NODE_FN (gbp_learn_ip6_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return (gbp_learn_l3 (vm, node, frame, FIB_PROTOCOL_IP6));
}
 
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (gbp_learn_ip4_node) = {
  .name = "gbp-learn-ip4",
  .vector_size = sizeof (u32),
  .format_trace = format_gbp_learn_l3_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
};
 
VNET_FEATURE_INIT (gbp_learn_ip4, static) =
{
  .arc_name = "ip4-unicast",
  .node_name = "gbp-learn-ip4",
};
 
VLIB_REGISTER_NODE (gbp_learn_ip6_node) = {
  .name = "gbp-learn-ip6",
  .vector_size = sizeof (u32),
  .format_trace = format_gbp_learn_l3_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
};
 
VNET_FEATURE_INIT (gbp_learn_ip6, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "gbp-learn-ip6",
};
 
/* *INDENT-ON* */
 
/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */