text: /*
   * Copyright (c) 2011-2016 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/cdp/cdp_node.h>
  
  cdp_main_t cdp_main;
  
  #define DEBUG_TLV_DUMP 0	/* 1=> dump TLV's to stdout while processing them */
  
  /* Reliable multicast messages we use to keep peers updated */
  mc_serialize_msg_t serialize_cdp_neighbor_msg;
  mc_serialize_msg_t serialize_cdp_keepalive_msg;
  
  /*
   * ported from an unspecified Cisco cdp implementation.
   * Compute / return in HOST byte order. 0 => good checksum.
   */
  u16
  cdp_checksum (void *p, int count)
  {
    u32 sum;
    u16 i, *data;
  
    data = p;
    sum = 0;
    while (count > 1)
      {
        sum += ntohs (*data);
        data++;
        count -= 2;
      }
  
    if (count > 0)
      sum += *(char *) data;
  
    while (sum >> 16)
      {
        sum = (sum & 0xFFFF) + (sum >> 16);
      }
  
    i = (i16) sum;
    return (~i);
  }
  
  /* TLV handler table */
  typedef struct
  {
    char *name;
    u32 tlv_id;
    void *format;
    void *process;
  } tlv_handler_t;
  
  static tlv_handler_t tlv_handlers[];
  
  /* Display a generic TLV as a set of hex bytes */
  static u8 *
  format_generic_tlv (u8 * s, va_list * va)
  {
    cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
    tlv_handler_t *h = &tlv_handlers[t->t];
  
    s = format (s, "%s(%d): %U\n", h->name,
  	      t->t, format_hex_bytes, t->v, t->l - sizeof (*t));
    return s;
  }
  
  /* Ignore / skip a TLV we don't support */
  static cdp_error_t
  process_generic_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
  {
  #if DEBUG_TLV_DUMP > 0
    fformat (stdout, "%U", format_generic_tlv, t);
  #endif
  
    return CDP_ERROR_NONE;
  }
  
  /* print a text tlv */
  static u8 *
  format_text_tlv (u8 * s, va_list * va)
  {
    cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
    tlv_handler_t *h = &tlv_handlers[t->t];
    int i;
  
    s = format (s, "%s(%d): ", h->name, t->t);
  
    for (i = 0; i < (t->l - sizeof (*t)); i++)
      vec_add1 (s, t->v[i]);
  
    vec_add1 (s, '\n');
    return s;
  }
  
  #if DEBUG_TLV_DUMP == 0
  /* gcc warning be gone */
  CLIB_UNUSED (static cdp_error_t
  	     process_text_tlv (cdp_main_t * cm, cdp_neighbor_t * n,
  			       cdp_tlv_t * t));
  #endif
  
  /* process / skip a generic text TLV that we don't support */
  static cdp_error_t
  process_text_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
  {
  #if DEBUG_TLV_DUMP > 0
    fformat (stdout, "%U\n", format_text_tlv, t);
  #endif
  
    return CDP_ERROR_NONE;
  }
  
  /* per-TLV format function definitions */
  #define format_unused_tlv format_generic_tlv
  #define format_device_name_tlv format_text_tlv
  #define format_address_tlv format_generic_tlv
  #define format_port_id_tlv format_text_tlv
  #define format_capabilities_tlv format_generic_tlv
  #define format_version_tlv format_text_tlv
  #define format_platform_tlv format_text_tlv
  #define format_ipprefix_tlv format_generic_tlv
  #define format_hello_tlv format_generic_tlv
  #define format_vtp_domain_tlv format_generic_tlv
  #define format_native_vlan_tlv format_generic_tlv
  #define format_duplex_tlv format_generic_tlv
  #define format_appl_vlan_tlv format_generic_tlv
  #define format_trigger_tlv format_generic_tlv
  #define format_power_tlv format_generic_tlv
  #define format_mtu_tlv format_generic_tlv
  #define format_trust_tlv format_generic_tlv
  #define format_cos_tlv format_generic_tlv
  #define format_sysname_tlv format_generic_tlv
  #define format_sysobject_tlv format_generic_tlv
  #define format_mgmt_addr_tlv format_generic_tlv
  #define format_physical_loc_tlv format_generic_tlv
  #define format_mgmt_addr2_tlv format_generic_tlv
  #define format_power_requested_tlv format_generic_tlv
  #define format_power_available_tlv format_generic_tlv
  #define format_port_unidirectional_tlv format_generic_tlv
  #define format_unknown_28_tlv format_generic_tlv
  #define format_energywise_tlv format_generic_tlv
  #define format_unknown_30_tlv format_generic_tlv
  #define format_spare_poe_tlv format_generic_tlv
  
  /* tlv ID=0 is a mistake */
  static cdp_error_t
  process_unused_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
  {
    return CDP_ERROR_BAD_TLV;
  }
  
  /* list of text TLV's that we snapshoot */
  #define foreach_text_to_struct_tlv              \
  _(device_name,DEBUG_TLV_DUMP)                   \
  _(version,DEBUG_TLV_DUMP)                       \
  _(platform,DEBUG_TLV_DUMP)                      \
  _(port_id,DEBUG_TLV_DUMP)
  
  #define _(z,dbg)                                                        \
  static                                                                  \
  cdp_error_t process_##z##_tlv (cdp_main_t *cm, cdp_neighbor_t *n,       \
                                    cdp_tlv_t *t)                         \
  {                                                                       \
      int i;                                                              \
      if (dbg)                                                            \
         fformat(stdout, "%U\n", format_text_tlv, t);                     \
                                                                          \
      if (n->z)                                                           \
          _vec_len(n->z) = 0;                                             \
                                                                          \
      for (i = 0; i < (t->l - sizeof (*t)); i++)                          \
          vec_add1(n->z, t->v[i]);                                        \
                                                                          \
      vec_add1(n->z, 0);                                                  \
                                                                          \
      return CDP_ERROR_NONE;                                              \
  }
  
  foreach_text_to_struct_tlv
  #undef _
  #define process_address_tlv process_generic_tlv
  #define process_capabilities_tlv process_generic_tlv
  #define process_ipprefix_tlv process_generic_tlv
  #define process_hello_tlv process_generic_tlv
  #define process_vtp_domain_tlv process_generic_tlv
  #define process_native_vlan_tlv process_generic_tlv
  #define process_duplex_tlv process_generic_tlv
  #define process_appl_vlan_tlv process_generic_tlv
  #define process_trigger_tlv process_generic_tlv
  #define process_power_tlv process_generic_tlv
  #define process_mtu_tlv process_generic_tlv
  #define process_trust_tlv process_generic_tlv
  #define process_cos_tlv process_generic_tlv
  #define process_sysname_tlv process_generic_tlv
  #define process_sysobject_tlv process_generic_tlv
  #define process_mgmt_addr_tlv process_generic_tlv
  #define process_physical_loc_tlv process_generic_tlv
  #define process_mgmt_addr2_tlv process_generic_tlv
  #define process_power_requested_tlv process_generic_tlv
  #define process_power_available_tlv process_generic_tlv
  #define process_port_unidirectional_tlv process_generic_tlv
  #define process_unknown_28_tlv process_generic_tlv
  #define process_energywise_tlv process_generic_tlv
  #define process_unknown_30_tlv process_generic_tlv
  #define process_spare_poe_tlv process_generic_tlv
  static tlv_handler_t tlv_handlers[] = {
  #define _(a) {#a, CDP_TLV_##a, format_##a##_tlv, process_##a##_tlv},
    foreach_cdp_tlv_type
  #undef _
  };
  
  #if DEBUG_TLV_DUMP == 0
  CLIB_UNUSED (static u8 * format_cdp_hdr (u8 * s, va_list * va));
  #endif
  
  static u8 *
  format_cdp_hdr (u8 * s, va_list * va)
  {
    cdp_hdr_t *h = va_arg (*va, cdp_hdr_t *);
  
    s = format (s, "version %d, ttl %d(secs), cksum 0x%04x\n",
  	      h->version, h->ttl, h->checksum);
    return s;
  }
  
  static cdp_error_t
  process_cdp_hdr (cdp_main_t * cm, cdp_neighbor_t * n, cdp_hdr_t * h)
  {
  #if DEBUG_TLV_DUMP > 0
    fformat (stdout, "%U", format_cdp_hdr, h);
  #endif
  
    if (h->version != 1 && h->version != 2)
      return CDP_ERROR_PROTOCOL_VERSION;
  
    n->ttl_in_seconds = h->ttl;
  
    return CDP_ERROR_NONE;
  }
  
  /* scan a cdp packet; header, then tlv's */
  static int
  cdp_packet_scan (cdp_main_t * cm, cdp_neighbor_t * n)
  {
    u8 *cur = n->last_rx_pkt;
    cdp_hdr_t *h;
    cdp_tlv_t *tlv;
    cdp_error_t e = CDP_ERROR_NONE;
    tlv_handler_t *handler;
    cdp_error_t (*fp) (cdp_main_t *, cdp_neighbor_t *, cdp_tlv_t *);
    u16 computed_checksum;
  
    computed_checksum = cdp_checksum (cur, vec_len (cur));
  
    if (computed_checksum)
      return CDP_ERROR_CHECKSUM;
  
    h = (cdp_hdr_t *) cur;
  
    e = process_cdp_hdr (cm, n, h);
    if (e)
      return e;
  
    cur = (u8 *) (h + 1);
  
    while (cur < n->last_rx_pkt + vec_len (n->last_rx_pkt) - 1)
      {
        tlv = (cdp_tlv_t *) cur;
        tlv->t = ntohs (tlv->t);
        tlv->l = ntohs (tlv->l);
        if (tlv->t >= ARRAY_LEN (tlv_handlers))
  	return CDP_ERROR_BAD_TLV;
        handler = &tlv_handlers[tlv->t];
        fp = handler->process;
        e = (*fp) (cm, n, tlv);
        if (e)
  	return e;
        /* tlv length includes (t, l) */
        cur += tlv->l;
      }
  
    return CDP_ERROR_NONE;
  }
  
  /*
   * cdp input routine
   */
  cdp_error_t
  cdp_input (vlib_main_t * vm, vlib_buffer_t * b0, u32 bi0)
  {
    cdp_main_t *cm = &cdp_main;
    cdp_neighbor_t *n;
    uword *p, nbytes;
    cdp_error_t e;
    uword last_packet_signature;
  
    /* find or create a neighbor pool entry for the (sw) interface
       upon which we received this pkt */
    p = hash_get (cm->neighbor_by_sw_if_index,
  		vnet_buffer (b0)->sw_if_index[VLIB_RX]);
  
    if (p == 0)
      {
        pool_get (cm->neighbors, n);
        memset (n, 0, sizeof (*n));
        n->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
        n->packet_template_index = (u8) ~ 0;
        hash_set (cm->neighbor_by_sw_if_index, n->sw_if_index,
  		n - cm->neighbors);
      }
    else
      {
        n = pool_elt_at_index (cm->neighbors, p[0]);
      }
  
    /*
     * typical clib idiom. Don't repeatedly allocate and free
     * the per-neighbor rx buffer. Reset its apparent length to zero
     * and reuse it.
     */
  
    if (n->last_rx_pkt)
      _vec_len (n->last_rx_pkt) = 0;
  
    /* cdp disabled on this interface, we're done */
    if (n->disabled)
      return CDP_ERROR_DISABLED;
  
    /*
     * Make sure the per-neighbor rx buffer is big enough to hold
     * the data we're about to copy
     */
    vec_validate (n->last_rx_pkt, vlib_buffer_length_in_chain (vm, b0) - 1);
  
    /*
     * Coalesce / copy e the buffer chain into the per-neighbor
     * rx buffer
     */
    nbytes = vlib_buffer_contents (vm, bi0, n->last_rx_pkt);
    ASSERT (nbytes <= vec_len (n->last_rx_pkt));
  
    /*
     * Compute Jenkins hash of the new packet, decide if we need to
     * actually parse through the TLV's. CDP packets are all identical,
     * so unless we time out the peer, we don't need to process the packet.
     */
    last_packet_signature =
      hash_memory (n->last_rx_pkt, vec_len (n->last_rx_pkt), 0xd00b);
  
    if (n->last_packet_signature_valid &&
        n->last_packet_signature == last_packet_signature)
      {
        e = CDP_ERROR_CACHE_HIT;
      }
    else
      {
        /* Actually scan the packet */
        e = cdp_packet_scan (cm, n);
        n->last_packet_signature_valid = 1;
        n->last_packet_signature = last_packet_signature;
      }
  
    if (e == CDP_ERROR_NONE)
      {
        n->last_heard = vlib_time_now (vm);
      }
  
    return e;
  }
  
  /*
   * setup neighbor hash table
   */
  static clib_error_t *
  cdp_init (vlib_main_t * vm)
  {
    clib_error_t *error;
    cdp_main_t *cm = &cdp_main;
    void vnet_cdp_node_reference (void);
  
    vnet_cdp_node_reference ();
  
    if ((error = vlib_call_init_function (vm, cdp_periodic_init)))
      return error;
  
    cm->vlib_main = vm;
    cm->vnet_main = vnet_get_main ();
    cm->neighbor_by_sw_if_index = hash_create (0, sizeof (uword));
  
    return 0;
  }
  
  VLIB_INIT_FUNCTION (cdp_init);
  
  
  static u8 *
  format_cdp_neighbors (u8 * s, va_list * va)
  {
    CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
    cdp_main_t *cm = va_arg (*va, cdp_main_t *);
    vnet_main_t *vnm = &vnet_main;
    cdp_neighbor_t *n;
    vnet_hw_interface_t *hw;
  
    s = format (s,
  	      "%=25s %=15s %=25s %=10s\n",
  	      "Our Port", "Peer System", "Peer Port", "Last Heard");
  
    /* *INDENT-OFF* */
    pool_foreach (n, cm->neighbors,
    ({
      hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
  
      if (n->disabled == 0)
        s = format (s, "%=25s %=15s %=25s %=10.1f\n",
                    hw->name, n->device_name, n->port_id,
                    n->last_heard);
    }));
    /* *INDENT-ON* */
    return s;
  }
  
  
  static clib_error_t *
  show_cdp (vlib_main_t * vm,
  	  unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    cdp_main_t *cm = &cdp_main;
  
    vlib_cli_output (vm, "%U\n", format_cdp_neighbors, vm, cm);
  
    return 0;
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (show_cdp_command, static) = {
    .path = "show cdp",
    .short_help = "Show cdp command",
    .function = show_cdp,
  };
  /* *INDENT-ON* */
  
  
  /*
   * packet trace format function, very similar to
   * cdp_packet_scan except that we call the per TLV format
   * functions instead of the per TLV processing functions
   */
  u8 *
  cdp_input_format_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 *);
    cdp_input_trace_t *t = va_arg (*args, cdp_input_trace_t *);
    u8 *cur;
    cdp_hdr_t *h;
    cdp_tlv_t *tlv;
    tlv_handler_t *handler;
    u8 *(*fp) (cdp_tlv_t *);
  
    cur = t->data;
  
    h = (cdp_hdr_t *) cur;
    s = format (s, "%U", format_cdp_hdr, h);
  
    cur = (u8 *) (h + 1);
  
    while (cur < t->data + t->len)
      {
        tlv = (cdp_tlv_t *) cur;
        tlv->t = ntohs (tlv->t);
        tlv->l = ntohs (tlv->l);
        if (tlv->t >= ARRAY_LEN (tlv_handlers))
  	{
  	  s = format (s, "BAD_TLV\n");
  	  break;
  	}
        handler = &tlv_handlers[tlv->t];
        fp = handler->format;
        s = format (s, "  %U", fp, tlv);
        /* tlv length includes (t, l) */
        cur += tlv->l;
      }
  
    return s;
  }
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  