l2_xcrw.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 <vnet/l2/l2_xcrw.h>

/* 
 * General L2 / L3 cross-connect, used to set up
 * "L2 interface <--> your-favorite-tunnel-encap" tunnels.
 *
 * We set up a typical L2 cross-connect or (future) bridge
 * to hook L2 interface(s) up to the L3 stack in arbitrary ways.
 *
 * Each l2_xcrw adjacency specifies 3 things:
 * 
 * 1. The next graph node (presumably in the L3 stack) to
 *    process the (L2 -> L3) packet
 *
 * 2. A new value for vnet_buffer(b)->sw_if_index[VLIB_TX] 
 *    (i.e. a lookup FIB index),
 *
 * 3. A rewrite string to apply.
 *
 * Example: to cross-connect an L2 interface or (future) bridge
 * to an mpls-o-gre tunnel, set up the L2 rewrite string as shown in 
 * mpls_gre_rewrite, and use "mpls-post-rewrite" to fix the
 * GRE IP header checksum and length fields.
 */

typedef struct {
  u32 next_index;
  u32 tx_fib_index;
} l2_xcrw_trace_t;

/* packet trace format function */
static u8 * format_l2_xcrw_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_xcrw_trace_t * t = va_arg (*args, l2_xcrw_trace_t *);
  
  s = format (s, "L2_XCRW: next index %d tx_fib_index %d",
              t->next_index, t->tx_fib_index);
  return s;
}

l2_xcrw_main_t l2_xcrw_main;

static vlib_node_registration_t l2_xcrw_node;

static char * l2_xcrw_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_xcrw_error
#undef _
};

static uword
l2_xcrw_node_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame)
{
  u32 n_left_from, * from, * to_next;
  l2_xcrw_next_t next_index;
  l2_xcrw_main_t * xcm = &l2_xcrw_main;
  vlib_node_t *n = vlib_get_node (vm, l2_xcrw_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;
          l2_xcrw_adjacency_t * adj0, * adj1;
          
          /* 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);

            CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
            CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
          }

          /* 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];

          adj0 = vec_elt_at_index (xcm->adj_by_sw_if_index, sw_if_index0);
          adj1 = vec_elt_at_index (xcm->adj_by_sw_if_index, sw_if_index1);

          next0 = adj0->rewrite_header.next_index;
          vnet_buffer(b0)->sw_if_index[VLIB_TX] = 
            adj0->rewrite_header.sw_if_index;

          next1 = adj1->rewrite_header.next_index;
          vnet_buffer(b1)->sw_if_index[VLIB_TX] = 
            adj1->rewrite_header.sw_if_index;

          em->counters[node_counter_base_index + next1]++;

          if (PREDICT_TRUE(next0 > 0))
            {
              u8 * h0 = vlib_buffer_get_current (b0);
              vnet_rewrite_one_header (adj0[0], h0, 
                                       adj0->rewrite_header.data_bytes);
              vlib_buffer_advance (b0, -adj0->rewrite_header.data_bytes);
              em->counters[node_counter_base_index + L2_XCRW_ERROR_FWD]++;
            }

          if (PREDICT_TRUE(next1 > 0))
            {
              u8 * h1 = vlib_buffer_get_current (b1);
              vnet_rewrite_one_header (adj1[0], h1, 
                                       adj1->rewrite_header.data_bytes);
              vlib_buffer_advance (b1, -adj1->rewrite_header.data_bytes);
              em->counters[node_counter_base_index + L2_XCRW_ERROR_FWD]++;
            }


          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)))
            {
              if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) 
                                && (b0->flags & VLIB_BUFFER_IS_TRACED))) 
                {
                  l2_xcrw_trace_t *t = 
                    vlib_add_trace (vm, node, b0, sizeof (*t));
                  t->next_index = next0;
                  t->tx_fib_index = adj0->rewrite_header.sw_if_index;
                }
              if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) 
                                && (b1->flags & VLIB_BUFFER_IS_TRACED))) 
                {
                  l2_xcrw_trace_t *t = 
                    vlib_add_trace (vm, node, b1, sizeof (*t));
                  t->next_index = next1;
                  t->tx_fib_index = adj1->rewrite_header.sw_if_index;
                }
            }
            
            /* 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;
          l2_xcrw_adjacency_t * adj0;
          
          /* 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];

          adj0 = vec_elt_at_index (xcm->adj_by_sw_if_index, sw_if_index0);

          next0 = adj0->rewrite_header.next_index;
          vnet_buffer(b0)->sw_if_index[VLIB_TX] = 
            adj0->rewrite_header.sw_if_index;

          if (PREDICT_TRUE(next0 > 0))
            {
              u8 *h0 = vlib_buffer_get_current (b0);
              vnet_rewrite_one_header (adj0[0], h0, 
                                       adj0->rewrite_header.data_bytes);
              vlib_buffer_advance (b0, -adj0->rewrite_header.data_bytes);
              em->counters[node_counter_base_index + L2_XCRW_ERROR_FWD]++;
            }

          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) 
                            && (b0->flags & VLIB_BUFFER_IS_TRACED))) 
            {
              l2_xcrw_trace_t *t = 
                vlib_add_trace (vm, node, b0, sizeof (*t));
              t->next_index = next0;
              t->tx_fib_index = adj0->rewrite_header.sw_if_index;
            }

          /* 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;
}

VLIB_REGISTER_NODE (l2_xcrw_node, static) = {
  .function = l2_xcrw_node_fn,
  .name = "l2-xcrw",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_xcrw_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  
  .n_errors = ARRAY_LEN(l2_xcrw_error_strings),
  .error_strings = l2_xcrw_error_strings,

  .n_next_nodes = L2_XCRW_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
        [L2_XCRW_NEXT_DROP] = "error-drop",
  },
};

clib_error_t *l2_xcrw_init (vlib_main_t *vm)
{
  l2_xcrw_main_t * mp = &l2_xcrw_main;
    
  mp->vlib_main = vm;
  mp->vnet_main = &vnet_main;
  mp->tunnel_index_by_l2_sw_if_index = hash_create (0, sizeof(uword));

  return 0;
}

VLIB_INIT_FUNCTION (l2_xcrw_init);

static uword dummy_interface_tx (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame)
{
  clib_warning ("you shouldn't be here, leaking buffers...");
  return frame->n_vectors;
}

static u8 * format_xcrw_name (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  return format (s, "xcrw%d", dev_instance);
}

VNET_DEVICE_CLASS (xcrw_device_class,static) = {
  .name = "Xcrw",
  .format_device_name = format_xcrw_name,
  .tx_function = dummy_interface_tx,
};

/* Create a sham tunnel interface and return its sw_if_index */
static u32
create_xcrw_interface (vlib_main_t * vm)
{
  vnet_main_t * vnm = vnet_get_main();
  static u32 instance;
  u8 address[6];
  u32 hw_if_index;
  vnet_hw_interface_t * hi;
  u32 sw_if_index;

  /* mac address doesn't really matter */
  memset (address, 0, sizeof (address));
  address[2] = 0x12;

  /* can returns error iff phy != 0 */
  (void) ethernet_register_interface
    (vnm,
     xcrw_device_class.index,
     instance++,
     address,
     &hw_if_index,
     /* flag change */ 0);

  hi = vnet_get_hw_interface (vnm, hw_if_index);
  sw_if_index = hi->sw_if_index;
  vnet_sw_interface_set_flags (vnm, sw_if_index, 
                               VNET_SW_INTERFACE_FLAG_ADMIN_UP);

  /* Output to the sham tunnel invokes the encap node */
  hi->output_node_index = l2_xcrw_node.index;

  return sw_if_index;
}

int vnet_configure_l2_xcrw (vlib_main_t * vm, vnet_main_t *vnm,
                            u32 l2_sw_if_index, u32 tx_fib_index,
                            u8 * rewrite, u32 next_node_index, int is_add)
{
  l2_xcrw_main_t * xcm = &l2_xcrw_main;
  l2_xcrw_adjacency_t * a;
  l2_xcrw_tunnel_t * t;
  uword * p;
  
  if (is_add)
    {

      pool_get (xcm->tunnels, t);

      /* No interface allocated? Do it. Otherwise, set admin up */
      if (t->tunnel_sw_if_index == 0)
        t->tunnel_sw_if_index = create_xcrw_interface (vm);
      else
        vnet_sw_interface_set_flags (vnm, t->tunnel_sw_if_index, 
                                     VNET_SW_INTERFACE_FLAG_ADMIN_UP);
        
      t->l2_sw_if_index = l2_sw_if_index;

      vec_validate (xcm->adj_by_sw_if_index, t->l2_sw_if_index);
      
      a = vec_elt_at_index (xcm->adj_by_sw_if_index, t->l2_sw_if_index);
      memset (a, 0, sizeof (*a));

      a->rewrite_header.sw_if_index = tx_fib_index;

      /* 
       * Add or find a dynamic disposition for the successor node, 
       * e.g. so we can ship pkts to mpls_post_rewrite...
       */
      a->rewrite_header.next_index = 
        vlib_node_add_next (vm, l2_xcrw_node.index, next_node_index);

      if (vec_len (rewrite))
          vnet_rewrite_set_data (a[0], rewrite, vec_len(rewrite));
      
      set_int_l2_mode (vm, vnm, MODE_L2_XC, t->l2_sw_if_index, 0, 0, 0, 
                       t->tunnel_sw_if_index);
      hash_set (xcm->tunnel_index_by_l2_sw_if_index, 
                t->l2_sw_if_index, t - xcm->tunnels);
      return 0;
    }
  else
    {
      p = hash_get (xcm->tunnel_index_by_l2_sw_if_index, l2_sw_if_index);
      if (p == 0)
        return VNET_API_ERROR_INVALID_SW_IF_INDEX;

      t = pool_elt_at_index (xcm->tunnels, p[0]);

      a = vec_elt_at_index (xcm->adj_by_sw_if_index, t->l2_sw_if_index);
      /* Reset adj to drop traffic */
      memset (a, 0, sizeof (*a));

      set_int_l2_mode (vm, vnm, MODE_L3, t->l2_sw_if_index, 0, 0, 0, 0);

      vnet_sw_interface_set_flags (vnm, t->tunnel_sw_if_index, 0 /* down */);

      hash_unset (xcm->tunnel_index_by_l2_sw_if_index, l2_sw_if_index);
      pool_put (xcm->tunnels, t);
    }
  return 0;
}


static clib_error_t *
set_l2_xcrw_command_fn (vlib_main_t * vm,
                        unformat_input_t * input,
                        vlib_cli_command_t * cmd)
{
  unformat_input_t _line_input, * line_input = &_line_input;
  int is_add = 1;
  int is_ipv6 = 0;              /* for fib id -> fib index mapping */
  u32 tx_fib_id = ~0;
  u32 tx_fib_index = ~0;
  u32 next_node_index = ~0;
  u32 l2_sw_if_index;
  u8 * rw = 0;
  vnet_main_t * vnm = vnet_get_main();
  int rv;
  
  
  if (! unformat_user (input, unformat_line_input, line_input))
    return 0;
  
  if (! unformat (line_input, "%U", 
                  unformat_vnet_sw_interface, vnm, &l2_sw_if_index))
    return clib_error_return (0, "unknown input '%U'",
                              format_unformat_error, line_input);
  
  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (line_input, "next %U", 
                    unformat_vlib_node, vm, &next_node_index))
        ;
      else if (unformat (line_input, "tx-fib-id %d", &tx_fib_id))
        ;
      else if (unformat (line_input, "del"))
        is_add = 0;
      else if (unformat (line_input, "ipv6"))
        is_ipv6 = 1;
      else if (unformat (line_input, "rw %U", 
                         unformat_hex_string, &rw));
      else
        break;
    }
        
  if (next_node_index == ~0)
    return clib_error_return (0, "next node not specified");
  
  if (tx_fib_id != ~0)
    {
      uword * p;

      if (is_ipv6)
        p = hash_get (ip6_main.fib_index_by_table_id, tx_fib_id);
      else
        p = hash_get (ip4_main.fib_index_by_table_id, tx_fib_id);

      if (p == 0)
        return clib_error_return (0, "nonexistent tx_fib_id %d", 
                                  tx_fib_id);

      tx_fib_index = p[0];
    }

  rv = vnet_configure_l2_xcrw (vm, vnm, l2_sw_if_index, tx_fib_index,
                               rw, next_node_index, is_add);

  switch (rv)
    {

    case 0:
      break;

    case VNET_API_ERROR_INVALID_SW_IF_INDEX:
      return clib_error_return (0, "%U not cross-connected",
                                format_vnet_sw_if_index_name,
                                vnm, l2_sw_if_index);
    default:
      return clib_error_return (0, "vnet_configure_l2_xcrw returned %d", 
                                rv);
    }
                               
  vec_free (rw);

  return 0;
}

VLIB_CLI_COMMAND (set_l2_xcrw_command, static) = {
  .path = "set interface l2 xcrw",
  .short_help = 
  "set int l2 xcrw <interface> next <node-name>\n"
  "    [del] [tx-fib-id <id>] [ipv6] rw <hex-bytes>",
  .function = set_l2_xcrw_command_fn,
};

static u8 * format_l2xcrw (u8 * s, va_list * args)
{
  vnet_main_t * vnm = va_arg (*args, vnet_main_t *);
  l2_xcrw_tunnel_t * t = va_arg (*args, l2_xcrw_tunnel_t *);
  l2_xcrw_main_t * xcm = &l2_xcrw_main;
  vlib_main_t * vm = vlib_get_main ();
  l2_xcrw_adjacency_t * a;
  u8 * rewrite_string;

  if (t == 0)
    {
      s = format (s, "%-25s%s", "L2 interface", "Tunnel Details");
      return s;
    }

  s = format (s, "%-25U %U ", 
              format_vnet_sw_if_index_name, vnm, t->l2_sw_if_index,
              format_vnet_sw_if_index_name, vnm, t->tunnel_sw_if_index);

  a = vec_elt_at_index (xcm->adj_by_sw_if_index, t->l2_sw_if_index);
  
  s = format (s, "next %U ",
              format_vlib_next_node_name, vm, l2_xcrw_node.index,
              a->rewrite_header.next_index);

  if (a->rewrite_header.sw_if_index != ~0)
    s = format (s, "tx fib index %d ", a->rewrite_header.sw_if_index);

  if (a->rewrite_header.data_bytes)
    {
      rewrite_string = (u8 *)(a + 1);
      rewrite_string -= a->rewrite_header.data_bytes;
      s = format (s, "rewrite data: %U ",
                  format_hex_bytes, rewrite_string, 
                  a->rewrite_header.data_bytes);
    }

  s = format (s, "\n");

  return s;
}


static clib_error_t *
show_l2xcrw_command_fn (vlib_main_t * vm,
                        unformat_input_t * input,
                        vlib_cli_command_t * cmd)
{
  vnet_main_t * vnm = vnet_get_main();
  l2_xcrw_main_t * xcm = &l2_xcrw_main;
  l2_xcrw_tunnel_t * t;

  if (pool_elts (xcm->tunnels) == 0)
    {
      vlib_cli_output (vm, "No L2 / L3 rewrite cross-connects configured");
      return 0;
    }

  vlib_cli_output (vm, "%U", format_l2xcrw, 0, 0);

  pool_foreach (t, xcm->tunnels, 
  ({
    vlib_cli_output (vm, "%U", format_l2xcrw, vnm, t);
  }));

  return 0;
}

VLIB_CLI_COMMAND (show_l2xcrw_command, static) = {
  .path = "show l2xcrw",
  .short_help = "Display L2/L3 rewrite cross-connects",
  .function = show_l2xcrw_command_fn,
};