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RIOT/sys/net/routing/nhdp/nhdp_reader.c 16 KB
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  /*
   * Copyright (C) 2014 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     nhdp
   * @{
   *
   * @file
   * @brief       Reader implementation for message processing in NHDP
   *
   * @author      Fabian Nack <nack@inf.fu-berlin.de>
   *
   * @}
   */
  
  #include "mutex.h"
  #include "utlist.h"
  
  #include "rfc5444/rfc5444.h"
  #include "rfc5444/rfc5444_iana.h"
  #include "rfc5444/rfc5444_reader.h"
  
  #include "lib_table.h"
  #include "nib_table.h"
  #include "iib_table.h"
  #include "nhdp.h"
  #include "nhdp_address.h"
  #include "nhdp_reader.h"
  
  /* Internal variables */
  struct rfc5444_reader reader;
  static mutex_t mtx_packet_handler = MUTEX_INIT;
  
  static iib_link_set_entry_t *originator_link_tuple = NULL;
  static uint32_t lt_metric_val = NHDP_METRIC_UNKNOWN;
  
  static kernel_pid_t if_pid;
  static uint64_t val_time;
  static uint64_t int_time;
  static uint8_t sym = 0;
  static uint8_t lost = 0;
  
  /* Internal function prototypes */
  static enum rfc5444_result _nhdp_pkt_end_cb(struct rfc5444_reader_tlvblock_context *context,
                                              bool dropped);
  static enum rfc5444_result _nhdp_blocktlv_msg_cb(struct rfc5444_reader_tlvblock_context *cont);
  static enum rfc5444_result _nhdp_blocktlv_address_cb(struct rfc5444_reader_tlvblock_context *cont);
  static enum rfc5444_result _nhdp_msg_end_cb(struct rfc5444_reader_tlvblock_context *cont,
          bool dropped);
  static enum rfc5444_result check_msg_validity(struct rfc5444_reader_tlvblock_context *cont);
  static enum rfc5444_result check_addr_validity(nhdp_addr_t *addr);
  static nhdp_addr_t *get_nhdp_db_addr(uint8_t *addr, uint8_t prefix);
  static void add_temp_metric_value(nhdp_addr_t *address);
  static void process_temp_tables(void);
  
  /* Array containing the processable message TLVs for HELLO messages */
  static struct rfc5444_reader_tlvblock_consumer_entry _nhdp_msg_tlvs[] = {
      [RFC5444_MSGTLV_INTERVAL_TIME] = { .type = RFC5444_MSGTLV_INTERVAL_TIME, .mandatory = false },
      [RFC5444_MSGTLV_VALIDITY_TIME] = { .type = RFC5444_MSGTLV_VALIDITY_TIME, .mandatory = true },
  };
  
  /* Array containing the processable address TLVs for HELLO message address blocks */
  static struct rfc5444_reader_tlvblock_consumer_entry _nhdp_addr_tlvs[] = {
      [RFC5444_ADDRTLV_LOCAL_IF] = { .type = RFC5444_ADDRTLV_LOCAL_IF },
      [RFC5444_ADDRTLV_LINK_STATUS] = { .type = RFC5444_ADDRTLV_LINK_STATUS },
      [RFC5444_ADDRTLV_OTHER_NEIGHB] = { .type = RFC5444_ADDRTLV_OTHER_NEIGHB },
      [RFC5444_ADDRTLV_LINK_METRIC] = { .type = RFC5444_ADDRTLV_LINK_METRIC, .type_ext = NHDP_METRIC,
                                        .match_type_ext = true, .min_length = 0x02,
                                        .max_length = 0x02, .match_length = true },
  };
  
  /* oonf_api packet consumer used for RFC5444 packet consumption */
  static struct rfc5444_reader_tlvblock_consumer _nhdp_packet_consumer = {
      .end_callback = _nhdp_pkt_end_cb,
  };
  
  /* oonf_api message consumer used for HELLO message consumption */
  static struct rfc5444_reader_tlvblock_consumer _nhdp_msg_consumer = {
      .msg_id = RFC5444_MSGTYPE_HELLO,
      .block_callback = _nhdp_blocktlv_msg_cb,
      .end_callback = _nhdp_msg_end_cb,
  };
  
  /* oonf_api message consumer user for HELLO message address block consumption */
  static struct rfc5444_reader_tlvblock_consumer _nhdp_address_consumer = {
      .msg_id = RFC5444_MSGTYPE_HELLO,
      .addrblock_consumer = true,
      .block_callback = _nhdp_blocktlv_address_cb,
  };
  
  
  /*---------------------------------------------------------------------------*
   *                             NHDP Reader API                               *
   *---------------------------------------------------------------------------*/
  
  void nhdp_reader_init(void)
  {
      /* Initialize reader */
      rfc5444_reader_init(&reader);
  
      /* Register packet consumer for sequence number processing */
      rfc5444_reader_add_packet_consumer(&reader, &_nhdp_packet_consumer, NULL, 0);
  
      /* Register HELLO message consumer */
      rfc5444_reader_add_message_consumer(&reader, &_nhdp_msg_consumer,
                                          _nhdp_msg_tlvs, ARRAYSIZE(_nhdp_msg_tlvs));
      rfc5444_reader_add_message_consumer(&reader, &_nhdp_address_consumer,
                                          _nhdp_addr_tlvs, ARRAYSIZE(_nhdp_addr_tlvs));
  }
  
  int nhdp_reader_handle_packet(kernel_pid_t rcvg_if_pid, void *buffer, size_t length)
  {
      int result;
  
      mutex_lock(&mtx_packet_handler);
  
      /* Store PID of interface this packet was received on */
      if_pid = rcvg_if_pid;
      /* Parse packet with reader */
      result = rfc5444_reader_handle_packet(&reader, buffer, length);
  
      mutex_unlock(&mtx_packet_handler);
  
      return result;
  }
  
  void nhdp_reader_cleanup(void)
  {
      rfc5444_reader_cleanup(&reader);
  }
  
  
  /*------------------------------------------------------------------------------------*/
  /*                                Internal functions                                  */
  /*------------------------------------------------------------------------------------*/
  
  /**
   * Process metric steps for packet with packet sequence number
   * Called by oonf_api after the whole packet was processed
   */
  static enum rfc5444_result _nhdp_pkt_end_cb(struct rfc5444_reader_tlvblock_context *context,
                                              bool dropped __attribute__((unused)))
  {
      /* Process metric changes */
      if ((originator_link_tuple != NULL) && (context->has_pktseqno)) {
          iib_process_metric_pckt(originator_link_tuple, lt_metric_val, context->pkt_seqno);
      }
  
      /* Reset originator temp fields */
      originator_link_tuple = NULL;
      lt_metric_val = NHDP_METRIC_UNKNOWN;
  
      return RFC5444_OKAY;
  }
  
  /**
   * Handle one address and its corresponding TLVs
   * Called by oonf_api for every included address to allow parsing
   */
  static enum rfc5444_result
  _nhdp_blocktlv_address_cb(struct rfc5444_reader_tlvblock_context *cont)
  {
      uint8_t tmp_result;
  
      /* Get NHDP address for the current netaddr */
      nhdp_addr_t *current_addr = get_nhdp_db_addr(&cont->addr._addr[0], cont->addr._prefix_len);
  
      if (!current_addr) {
          /* Insufficient memory */
          return RFC5444_DROP_MESSAGE;
      }
  
      /* Check validity of address tlvs */
      if (check_addr_validity(current_addr) != RFC5444_OKAY) {
          nhdp_decrement_addr_usage(current_addr);
          return RFC5444_DROP_MESSAGE;
      }
  
      /* Handle address and add it to proper temporary list */
      if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LOCAL_IF].tlv) {
          switch (*_nhdp_addr_tlvs[RFC5444_ADDRTLV_LOCAL_IF].tlv->single_value) {
              case RFC5444_LOCALIF_THIS_IF:
                  current_addr->in_tmp_table = NHDP_ADDR_TMP_SEND_LIST;
                  break;
  
              case RFC5444_LOCALIF_OTHER_IF:
                  current_addr->in_tmp_table = NHDP_ADDR_TMP_NB_LIST;
                  break;
  
              default:
                  /* Wrong value, drop message */
                  nhdp_decrement_addr_usage(current_addr);
                  return RFC5444_DROP_MESSAGE;
          }
      }
      else if ((tmp_result = lib_is_reg_addr(if_pid, current_addr))) {
          /* The address is one of our local addresses (do not add it for processing) */
          if ((!sym) && (tmp_result == 1) && _nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv) {
              /* If address is a local address of the receiving interface, check */
              /* whether we can derive a status for this link (symmetry or lost) */
              switch (*_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv->single_value) {
                  case RFC5444_LINKSTATUS_SYMMETRIC:
                      /* Fall - through */
  
                  case RFC5444_LINKSTATUS_HEARD:
                      sym = 1;
                      break;
  
                  case RFC5444_LINKSTATUS_LOST:
                      lost = 1;
                      break;
  
                  default:
                      /* Wrong value, drop message */
                      nhdp_decrement_addr_usage(current_addr);
                      return RFC5444_DROP_MESSAGE;
              }
          }
  
          if (lt_metric_val == NHDP_METRIC_UNKNOWN
              && _nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_METRIC].tlv != NULL) {
              /* Determine our outgoing link metric value to the originator interface */
              uint16_t metric_enc = *((uint16_t*)_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_METRIC]
                                                        .tlv->single_value);
              if (metric_enc & NHDP_KD_LM_INC) {
                  /* Incoming metric value at the neighbor if is outgoing value for our if */
                  lt_metric_val = rfc5444_metric_decode(metric_enc);
              }
          }
  
          /* Address is one of our own addresses, ignore it */
          nhdp_decrement_addr_usage(current_addr);
      }
      else if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv) {
          switch (*_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv->single_value) {
              case RFC5444_LINKSTATUS_SYMMETRIC:
                  add_temp_metric_value(current_addr);
                  current_addr->in_tmp_table = NHDP_ADDR_TMP_TH_SYM_LIST;
                  break;
  
              case RFC5444_LINKSTATUS_HEARD:
                  /* Fall-through */
  
              case RFC5444_LINKSTATUS_LOST:
                  if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv
                      && *_nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv->single_value
                      == RFC5444_OTHERNEIGHB_SYMMETRIC) {
                      /* Symmetric has higher priority */
                      add_temp_metric_value(current_addr);
                      current_addr->in_tmp_table = NHDP_ADDR_TMP_TH_SYM_LIST;
                  }
                  else {
                      current_addr->in_tmp_table = NHDP_ADDR_TMP_TH_REM_LIST;
                  }
  
                  break;
  
              default:
                  /* Wrong value, drop message */
                  nhdp_decrement_addr_usage(current_addr);
                  return RFC5444_DROP_MESSAGE;
          }
      }
      else if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv) {
          switch (*_nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv->single_value) {
              case RFC5444_OTHERNEIGHB_SYMMETRIC:
                  add_temp_metric_value(current_addr);
                  current_addr->in_tmp_table = NHDP_ADDR_TMP_TH_SYM_LIST;
                  break;
  
              case RFC5444_OTHERNEIGHB_LOST:
                  current_addr->in_tmp_table = NHDP_ADDR_TMP_TH_REM_LIST;
                  break;
  
              default:
                  /* Wrong value, drop message */
                  nhdp_decrement_addr_usage(current_addr);
                  return RFC5444_DROP_MESSAGE;
          }
      }
      else {
          /* Addresses without expected TLV are ignored */
          nhdp_decrement_addr_usage(current_addr);
          return RFC5444_DROP_ADDRESS;
      }
  
      return RFC5444_OKAY;
  }
  
  /**
   * Handle message TLVs of received HELLO
   * Called by oonf_api to allow message TLV parsing
   */
  static enum rfc5444_result
  _nhdp_blocktlv_msg_cb(struct rfc5444_reader_tlvblock_context *cont)
  {
      /* Check whether specified message TLVs are correctly included */
      if (check_msg_validity(cont) != RFC5444_OKAY) {
          return RFC5444_DROP_MESSAGE;
      }
  
      /* Validity time must be included as message tlv */
      val_time = rfc5444_timetlv_decode(
                     *_nhdp_msg_tlvs[RFC5444_MSGTLV_VALIDITY_TIME].tlv->single_value);
  
      /* Interval time is not mandatory as message tlv */
      if (_nhdp_msg_tlvs[RFC5444_MSGTLV_INTERVAL_TIME].tlv) {
          int_time = rfc5444_timetlv_decode(
                         *_nhdp_msg_tlvs[RFC5444_MSGTLV_INTERVAL_TIME].tlv->single_value);
      }
  
      return RFC5444_OKAY;
  }
  
  /**
   * Process received addresses and clean up temporary stuff
   * Called by oonf_api after message was parsed
   */
  static enum rfc5444_result
  _nhdp_msg_end_cb(struct rfc5444_reader_tlvblock_context *cont __attribute__((unused)),
                   bool dropped)
  {
      if (!dropped) {
          /* Only process the received addresses if message was valid */
          process_temp_tables();
      }
  
      /* Clean all temporary stuff */
      val_time = 0ULL;
      int_time = 0ULL;
      sym = 0;
      lost = 0;
      nhdp_reset_addresses_tmp_usg(1);
  
      if (dropped) {
          return RFC5444_DROP_MESSAGE;
      }
  
      return RFC5444_OKAY;
  }
  
  /**
   * Check validity of HELLO message header and message TLVs
   */
  static enum rfc5444_result check_msg_validity(struct rfc5444_reader_tlvblock_context *cont)
  {
      if (cont->has_hoplimit && cont->hoplimit != 1) {
          /* Hop Limit other than 1 */
          return RFC5444_DROP_MESSAGE;
      }
  
      if (cont->has_hopcount && cont->hopcount != 0) {
          /* Hop Count other than zero */
          return RFC5444_DROP_MESSAGE;
      }
  
      if (!(_nhdp_msg_tlvs[RFC5444_MSGTLV_VALIDITY_TIME].tlv)) {
          /* No validity time tlv */
          return RFC5444_DROP_MESSAGE;
      }
      else if (_nhdp_msg_tlvs[RFC5444_MSGTLV_VALIDITY_TIME].tlv->next_entry) {
          /* Multiple validity time tlvs */
          return RFC5444_DROP_MESSAGE;
      }
  
      if (_nhdp_msg_tlvs[RFC5444_MSGTLV_INTERVAL_TIME].tlv
          && _nhdp_msg_tlvs[RFC5444_MSGTLV_INTERVAL_TIME].tlv->next_entry) {
          /* Multiple interval time tlvs */
          return RFC5444_DROP_MESSAGE;
      }
  
      return RFC5444_OKAY;
  }
  
  /**
   * Check validity of address block TLVs
   */
  static enum rfc5444_result check_addr_validity(nhdp_addr_t *addr)
  {
      if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LOCAL_IF].tlv) {
          if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv
              || _nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv) {
              /* Conflicting tlv types for the address */
              return RFC5444_DROP_MESSAGE;
          }
          else if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LOCAL_IF].tlv->next_entry) {
              /* Multiple tlvs of the same type are not allowed */
              return RFC5444_DROP_MESSAGE;
          }
          else if (lib_is_reg_addr(if_pid, addr)) {
              /* Address of one of neighbor's IFs equals one of ours */
              return RFC5444_DROP_MESSAGE;
          }
      }
      else if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv
               && _nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_STATUS].tlv->next_entry) {
          /* Multiple tlvs of the same type are not allowed */
          return RFC5444_DROP_MESSAGE;
      }
      else if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv
               && _nhdp_addr_tlvs[RFC5444_ADDRTLV_OTHER_NEIGHB].tlv->next_entry) {
          /* Multiple tlvs of the same type are not allowed */
          return RFC5444_DROP_MESSAGE;
      }
  
      return RFC5444_OKAY;
  }
  
  /**
   * Get a new or existing NHDP address entry from the centralized address storage
   * for the given address data
   */
  static nhdp_addr_t *get_nhdp_db_addr(uint8_t *addr, uint8_t prefix)
  {
      switch (prefix) {
          case 8:
              return nhdp_addr_db_get_address(addr, 1, AF_CC110X);
  
          case 32:
              return nhdp_addr_db_get_address(addr, 4, AF_INET);
  
          default:
              if (prefix < 32) {
                  return nhdp_addr_db_get_address(addr, 4, AF_INET);
              }
              else {
                  return nhdp_addr_db_get_address(addr, 16, AF_INET6);
              }
      }
  }
  
  /**
   * Add a metric value to the address if a corresponding TLV exists in the message
   */
  static void add_temp_metric_value(nhdp_addr_t *address)
  {
      if (_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_METRIC].tlv) {
          uint16_t metric_enc = *((uint16_t*)_nhdp_addr_tlvs[RFC5444_ADDRTLV_LINK_METRIC]
                                                             .tlv->single_value);
          if (metric_enc & (NHDP_KD_LM_INC | NHDP_KD_NM_INC)) {
              address->tmp_metric_val = metric_enc;
          }
      }
  }
  
  /**
   * Process address lists from the HELLO msg in the information bases
   */
  static void process_temp_tables(void)
  {
      nib_entry_t *nib_elt;
      timex_t now;
  
      xtimer_now_timex(&now);
      iib_update_lt_status(&now);
  
      nib_elt = nib_process_hello();
  
      if (nib_elt) {
          originator_link_tuple = iib_process_hello(if_pid, nib_elt, val_time, sym, lost);
  
          if (originator_link_tuple) {
              iib_process_metric_msg(originator_link_tuple, int_time != 0 ? int_time : val_time);
          }
      }
  }