text: /*
   * nsim.c - skeleton vpp engine plug-in
   *
   * Copyright (c) <current-year> <your-organization>
   * 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 <vlib/vlib.h>
  #include <vnet/vnet.h>
  #include <vnet/pg/pg.h>
  #include <vppinfra/error.h>
  #include <nsim/nsim.h>
  
  typedef struct
  {
    f64 expired;
    u32 tx_sw_if_index;
  } nsim_tx_trace_t;
  
  #ifndef CLIB_MARCH_VARIANT
  /* packet trace format function */
  static u8 *
  format_nsim_tx_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 *);
    nsim_tx_trace_t *t = va_arg (*args, nsim_tx_trace_t *);
  
    s = format (s, "NSIM: tx at %.6f sw_if_index %d",
  	      t->expired, t->tx_sw_if_index);
    return s;
  }
  #endif /* CLIB_MARCH_VARIANT */
  
  #define foreach_nsim_tx_error                      \
  _(TX, "Packets transmitted")                    \
  _(DROPPED, "No buffer drops")
  
  typedef enum
  {
  #define _(sym,str) NSIM_TX_ERROR_##sym,
    foreach_nsim_tx_error
  #undef _
      NSIM_N_ERROR,
  } nsim_tx_error_t;
  
  #ifndef CLIB_MARCH_VARIANT
  static char *nsim_tx_error_strings[] = {
  #define _(sym,string) string,
    foreach_nsim_tx_error
  #undef _
  };
  #endif /* CLIB_MARCH_VARIANT */
  
  typedef enum
  {
    NSIM_NEXT_DROP,
    NSIM_N_NEXT,
  } nsim_next_t;
  
  always_inline uword
  nsim_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
  		   vlib_frame_t * f, int is_trace)
  {
    nsim_main_t *nsm = &nsim_main;
    u32 my_thread_index = vm->thread_index;
    u32 *my_buffer_cache = nsm->buffer_indices_by_thread[my_thread_index];
    nsim_wheel_t *wp = nsm->wheel_by_thread[my_thread_index];
    u32 n_trace = vlib_get_trace_count (vm, node);
    f64 now = vlib_time_now (vm);
    uword n_rx_packets = 0;
    vlib_buffer_t *b0;
    u32 bi0, next0;
    u32 *to_next;
    u32 next_index;
    u32 n_left_to_next;
    nsim_wheel_entry_t *ep;
  
    /* Nothing on the scheduler wheel? */
    if (wp->cursize == 0)
      return 0;
  
    /* First entry on the wheel isn't expired? */
    ep = wp->entries + wp->head;
    if (ep->tx_time > now)
      return n_rx_packets;
  
    /*
     * We use per-thread buffer caches, so we need the freelist to
     * initialize them...
     */
    next_index = node->cached_next_index;
  
    while (wp->cursize)
      {
        /* Be aware: this is not the usual coding pattern */
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_to_next > 0 && ep->tx_time <= now)
  	{
  	  /* Out of local buffer cache? */
  	  if (PREDICT_FALSE (_vec_len (my_buffer_cache) == 0))
  	    {
  	      u32 n =
  		vlib_buffer_alloc (vm, my_buffer_cache, VLIB_FRAME_SIZE);
  	      _vec_len (my_buffer_cache) = n;
  
  	      /* Ugh, drop the rest of the expired entries */
  	      if (n == 0)
  		{
  		  u32 drops = 0;
  		  while (ep->tx_time <= now && wp->cursize)
  		    {
  		      wp->head++;
  		      if (wp->head == wp->wheel_size)
  			wp->head = 0;
  		      ep = wp->entries + wp->head;
  		      wp->cursize--;
  		      drops++;
  		    }
  		  /* Count the drops */
  		  vlib_node_increment_counter (vm, node->node_index,
  					       NSIM_TX_ERROR_DROPPED, drops);
  		  /* Ship any pkts we already processed */
  		  vlib_put_next_frame (vm, node, next_index, n_left_to_next);
  		  return n_rx_packets + drops;
  		}
  	    }
  
  	  /* Allocate a buffer */
  	  bi0 = my_buffer_cache[_vec_len (my_buffer_cache) - 1];
  	  _vec_len (my_buffer_cache) -= 1;
  
  	  to_next[0] = bi0;
  	  to_next += 1;
  	  n_left_to_next -= 1;
  
  	  b0 = vlib_get_buffer (vm, bi0);
  	  /* Initialize the buffer */
  
  	  b0->current_data = 0;
  	  b0->current_length = ep->current_length;
  
  	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
  
  	  if (PREDICT_FALSE (n_trace))
  	    {
  	      nsim_tx_trace_t *t0;
  	      vlib_trace_buffer (vm, node, next_index, b0,
  				 0 /* follow_chain */ );
  	      t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
  	      t0->expired = ep->tx_time;
  	      t0->tx_sw_if_index = ep->tx_sw_if_index;
  	    }
  
  	  /* Copy data from the ring */
  	  clib_memcpy_fast (b0->data, ep->data, ep->current_length);
  	  b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
  	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ep->tx_sw_if_index;
  	  vnet_buffer (b0)->sw_if_index[VLIB_RX] =
  	    (ep->tx_sw_if_index == nsm->sw_if_index0) ? nsm->sw_if_index1 :
  	    nsm->sw_if_index0;
  	  next0 = (ep->tx_sw_if_index == nsm->sw_if_index0) ?
  	    nsm->output_next_index0 : nsm->output_next_index1;
  
  	  /* 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);
  	  /* Advance to the next ring entry */
  	  wp->head++;
  	  if (wp->head == wp->wheel_size)
  	    wp->head = 0;
  	  wp->cursize--;
  	  ep = wp->entries + wp->head;
  	  n_rx_packets++;
  
  	  /* Out of ring entries? */
  	  if (PREDICT_FALSE (wp->cursize == 0))
  	    break;
  	}
  
        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
  
        /* If the current entry hasn't expired, we're done */
        if (ep->tx_time > now)
  	break;
      }
    return n_rx_packets;
  }
  
  VLIB_NODE_FN (nsim_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
  				vlib_frame_t * frame)
  {
    if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
      return nsim_input_inline (vm, node, frame, 1 /* is_trace */ );
    else
      return nsim_input_inline (vm, node, frame, 0 /* is_trace */ );
  
  }
  
  /* *INDENT-OFF* */
  #ifndef CLIB_MARCH_VARIANT
  VLIB_REGISTER_NODE (nsim_input_node) =
  {
    .type = VLIB_NODE_TYPE_INPUT,
    .name = "nsim-wheel",
  
    /* Will be enabled if/when the feature is configured */
    .state = VLIB_NODE_STATE_DISABLED,
  
    .format_trace = format_nsim_tx_trace,
  
    .n_errors = NSIM_N_ERROR,
    .error_strings = nsim_tx_error_strings,
  };
  #endif /* CLIB_MARCH_VARIANT */
  /* *INDENT-ON* */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  