l2_patch.c

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/*
 * 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.
 */
#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/pg/pg.h>
#include <vnet/ethernet/ethernet.h>
#include <vppinfra/error.h>

typedef struct {
  u32 cached_next_index;
  u32 cached_rx_sw_if_index;

  /* vector of dispositions, indexed by rx_sw_if_index */
  u32 *tx_next_by_rx_sw_if_index;
  u32 *tx_sw_if_index_by_rx_sw_if_index;

  /* convenience variables */
  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;
} l2_patch_main_t;

typedef struct {
  u32 rx_sw_if_index;
  u32 tx_sw_if_index;
} l2_patch_trace_t;

/* packet trace format function */
static u8 * format_l2_patch_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 *);
  l2_patch_trace_t * t = va_arg (*args, l2_patch_trace_t *);
  
  s = format (s, "L2_PATCH: rx %d tx %d", t->rx_sw_if_index,
              t->tx_sw_if_index);
  return s;
}

l2_patch_main_t l2_patch_main;

static vlib_node_registration_t l2_patch_node;

#define foreach_l2_patch_error                  \
_(PATCHED, "L2 patch packets")                  \
_(DROPPED, "L2 patch misconfigured drops")

typedef enum {
#define _(sym,str) L2_PATCH_ERROR_##sym,
  foreach_l2_patch_error
#undef _
  L2_PATCH_N_ERROR,
} l2_patch_error_t;

static char * l2_patch_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_patch_error
#undef _
};

typedef enum {
  L2_PATCH_NEXT_DROP,
  L2_PATCH_N_NEXT,
} l2_patch_next_t;

static uword
l2_patch_node_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame)
{
  u32 n_left_from, * from, * to_next;
  l2_patch_next_t next_index;
  l2_patch_main_t * l2pm = &l2_patch_main;
  vlib_node_t *n = vlib_get_node (vm, l2_patch_node.index);
  u32 node_counter_base_index = n->error_heap_index;
  vlib_error_main_t * em = &vm->error_main;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  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 >= 4 && n_left_to_next >= 2)
        {
          u32 bi0, bi1;
          vlib_buffer_t * b0, * b1;
          u32 next0, next1;
          u32 sw_if_index0, sw_if_index1;
          
          /* Prefetch next iteration. */
          {
            vlib_buffer_t * p2, * p3;
            
            p2 = vlib_get_buffer (vm, from[2]);
            p3 = vlib_get_buffer (vm, from[3]);
            
            vlib_prefetch_buffer_header (p2, LOAD);
            vlib_prefetch_buffer_header (p3, LOAD);

            /* So stupid / simple, we don't need to prefetch data */
          }

          /* speculatively enqueue b0 and b1 to the current next frame */
          to_next[0] = bi0 = from[0];
          to_next[1] = bi1 = from[1];
          from += 2;
          to_next += 2;
          n_left_from -= 2;
          n_left_to_next -= 2;

          b0 = vlib_get_buffer (vm, bi0);
          b1 = vlib_get_buffer (vm, bi1);

          sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
          sw_if_index1 = vnet_buffer(b1)->sw_if_index[VLIB_RX];
          
          ASSERT(l2pm->tx_next_by_rx_sw_if_index[sw_if_index0] != ~0);
          ASSERT(l2pm->tx_sw_if_index_by_rx_sw_if_index[sw_if_index0] != ~0);
          ASSERT(l2pm->tx_next_by_rx_sw_if_index[sw_if_index1] != ~0);
          ASSERT(l2pm->tx_sw_if_index_by_rx_sw_if_index[sw_if_index1] != ~0);

          if (PREDICT_TRUE (sw_if_index0 == l2pm->cached_rx_sw_if_index))
            next0 = l2pm->cached_next_index;
          else
            {
              next0 = l2pm->tx_next_by_rx_sw_if_index[sw_if_index0];
              l2pm->cached_rx_sw_if_index = sw_if_index0;
              l2pm->cached_next_index = next0;
            }
          
          if (PREDICT_TRUE (sw_if_index1 == l2pm->cached_rx_sw_if_index))
            next1 = l2pm->cached_next_index;
          else 
            next1 = l2pm->tx_next_by_rx_sw_if_index [sw_if_index1];
          
          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)))
            {
              if (b0->flags & VLIB_BUFFER_IS_TRACED) 
                {
                    l2_patch_trace_t *t = 
                      vlib_add_trace (vm, node, b0, sizeof (*t));
                    t->rx_sw_if_index = sw_if_index0;
                    t->tx_sw_if_index = 
                      l2pm->tx_sw_if_index_by_rx_sw_if_index [sw_if_index0];
                  }
              if (b1->flags & VLIB_BUFFER_IS_TRACED) 
                {
                    l2_patch_trace_t *t = 
                      vlib_add_trace (vm, node, b1, sizeof (*t));
                    t->rx_sw_if_index = sw_if_index1;
                    t->tx_sw_if_index = 
                      l2pm->tx_sw_if_index_by_rx_sw_if_index [sw_if_index1];
                  }
              }
            
            /* verify speculative enqueues, maybe switch current next frame */
            vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
                                             to_next, n_left_to_next,
                                             bi0, bi1, next0, next1);
        }
      
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t * b0;
          u32 next0;
          u32 sw_if_index0;

          /* speculatively enqueue b0 to the current next frame */
          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];

          ASSERT(l2pm->tx_next_by_rx_sw_if_index[sw_if_index0] != ~0);
          ASSERT(l2pm->tx_sw_if_index_by_rx_sw_if_index[sw_if_index0] != ~0);

          if (PREDICT_TRUE (sw_if_index0 == l2pm->cached_rx_sw_if_index))
            next0 = l2pm->cached_next_index;
          else
            {
              next0 = l2pm->tx_next_by_rx_sw_if_index [sw_if_index0];
              l2pm->cached_rx_sw_if_index = sw_if_index0;
              l2pm->cached_next_index = next0;
            }

          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)))
            {
              if (b0->flags & VLIB_BUFFER_IS_TRACED) 
                {
                    l2_patch_trace_t *t = 
                      vlib_add_trace (vm, node, b0, sizeof (*t));
                    t->rx_sw_if_index = sw_if_index0;
                    t->tx_sw_if_index = 
                      l2pm->tx_sw_if_index_by_rx_sw_if_index [sw_if_index0];
                  }
            }

          /* 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);
    }

  em->counters[node_counter_base_index + L2_PATCH_ERROR_PATCHED] += 
    frame->n_vectors;

  return frame->n_vectors;
}

VLIB_REGISTER_NODE (l2_patch_node, static) = {
  .function = l2_patch_node_fn,
  .name = "l2_patch",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_patch_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  
  .n_errors = ARRAY_LEN(l2_patch_error_strings),
  .error_strings = l2_patch_error_strings,

  .n_next_nodes = L2_PATCH_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
        [L2_PATCH_NEXT_DROP] = "error-drop",
  },
};

int vnet_l2_patch_add_del (u32 rx_sw_if_index, u32 tx_sw_if_index, int is_add)
{
  l2_patch_main_t * l2pm = &l2_patch_main;  
  vnet_hw_interface_t * rxhi, *txhi;
  u32 tx_next_index;

  /* 
   * We assume that the API msg handler has used 2x VALIDATE_SW_IF_INDEX
   * macros...
   */

  rxhi = vnet_get_sup_hw_interface (l2pm->vnet_main, rx_sw_if_index);

  /* Make sure caller didn't pass a vlan subif, etc. */
  if (rxhi->sw_if_index != rx_sw_if_index)
    return VNET_API_ERROR_INVALID_SW_IF_INDEX;

  txhi = vnet_get_sup_hw_interface (l2pm->vnet_main, tx_sw_if_index);
  if (txhi->sw_if_index != tx_sw_if_index)
    return VNET_API_ERROR_INVALID_SW_IF_INDEX_2;

  if (is_add)
    {
      tx_next_index = vlib_node_add_next (l2pm->vlib_main,
                                          l2_patch_node.index,
                                          txhi->output_node_index);

      vec_validate_init_empty (l2pm->tx_next_by_rx_sw_if_index,
                               rx_sw_if_index, ~0);
      
      l2pm->tx_next_by_rx_sw_if_index[rx_sw_if_index] = tx_next_index;
      vec_validate_init_empty (l2pm->tx_sw_if_index_by_rx_sw_if_index,
                               rx_sw_if_index, ~0);
      l2pm->tx_sw_if_index_by_rx_sw_if_index[rx_sw_if_index] 
        = txhi->sw_if_index;
      
      ethernet_set_flags (l2pm->vnet_main, rxhi->hw_if_index, 
                          ETHERNET_INTERFACE_FLAG_ACCEPT_ALL);

      vnet_hw_interface_rx_redirect_to_node (l2pm->vnet_main, 
                                             rxhi->hw_if_index,
                                             l2_patch_node.index);
    }
  else
    {
      ethernet_set_flags (l2pm->vnet_main, rxhi->hw_if_index, 
                          0 /* disable promiscuous mode */);

      vnet_hw_interface_rx_redirect_to_node (l2pm->vnet_main, 
                                             rxhi->hw_if_index,
                                             ~0 /* disable */);
      if (vec_len (l2pm->tx_next_by_rx_sw_if_index) > rx_sw_if_index)
        {
          l2pm->tx_next_by_rx_sw_if_index[rx_sw_if_index] = ~0;
          l2pm->tx_sw_if_index_by_rx_sw_if_index[rx_sw_if_index] = ~0;
        }
    }
  
  return 0;
}

static clib_error_t *
test_patch_command_fn (vlib_main_t * vm,
                         unformat_input_t * input,
                         vlib_cli_command_t * cmd)
{
  l2_patch_main_t * l2pm = &l2_patch_main;  
  unformat_input_t _line_input, * line_input = &_line_input;
  u32 rx_sw_if_index, tx_sw_if_index;
  int rv;
  int rx_set = 0;
  int tx_set = 0;
  int is_add = 1;

  /* Get a line of input. */
  if (! unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (line_input, "rx %U", unformat_vnet_sw_interface,
                    l2pm->vnet_main, &rx_sw_if_index))
        rx_set = 1;
      else if (unformat (line_input, "tx %U", unformat_vnet_sw_interface,
                         l2pm->vnet_main, &tx_sw_if_index))
        tx_set = 1;
      else if (unformat (line_input, "del"))
        is_add = 0;
      else break;
    }

  if (rx_set == 0)
    return clib_error_return (0, "rx interface not set");

  if (tx_set == 0)
    return clib_error_return (0, "tx interface not set");

  rv = vnet_l2_patch_add_del (rx_sw_if_index, tx_sw_if_index, is_add);

  switch (rv)
    {
    case 0:
      break;

    case VNET_API_ERROR_INVALID_SW_IF_INDEX:
      return clib_error_return (0, "rx interface not a physical port");

    case VNET_API_ERROR_INVALID_SW_IF_INDEX_2:
      return clib_error_return (0, "tx interface not a physical port");

    default:
      return clib_error_return 
        (0, "WARNING: vnet_l2_patch_add_del returned %d", rv);
    }
  
  return 0;
}

VLIB_CLI_COMMAND (test_patch_command, static) = {
    .path = "test l2patch",
    .short_help = 
    "rx <intfc> tx <intfc> [del]",
    .function = test_patch_command_fn,
};

// Display the contents of the l2patch table.
static clib_error_t *
show_l2patch  (vlib_main_t * vm,
               unformat_input_t * input,
               vlib_cli_command_t * cmd)
{
  l2_patch_main_t * l2pm = &l2_patch_main;
  u32 rx_sw_if_index;
  u32 no_entries = 1;

  ASSERT(vec_len(l2pm->tx_next_by_rx_sw_if_index) == 
         vec_len(l2pm->tx_sw_if_index_by_rx_sw_if_index));
  
  for (rx_sw_if_index = 0; 
       rx_sw_if_index < vec_len (l2pm->tx_sw_if_index_by_rx_sw_if_index); 
       rx_sw_if_index++)
    {
      u32 tx_sw_if_index =
        l2pm->tx_sw_if_index_by_rx_sw_if_index[rx_sw_if_index];
      if (tx_sw_if_index != ~0)
        {
          no_entries = 0;
          vlib_cli_output (vm, "%26U -> %U",
                           format_vnet_sw_if_index_name,
                           l2pm->vnet_main, rx_sw_if_index,
                           format_vnet_sw_if_index_name, 
                           l2pm->vnet_main,tx_sw_if_index);
        }
    }

  if (no_entries)
    vlib_cli_output (vm, "no l2patch entries");

  return 0;
}

VLIB_CLI_COMMAND (show_l2patch_cli, static) = {
  .path = "show l2patch",
  .short_help = "Show l2 interface cross-connect entries",
  .function = show_l2patch,
};

clib_error_t *l2_patch_init (vlib_main_t *vm)
{
  l2_patch_main_t * mp = &l2_patch_main;
    
  mp->vlib_main = vm;
  mp->vnet_main = vnet_get_main();

  return 0;
}

VLIB_INIT_FUNCTION (l2_patch_init);