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RIOT/sys/net/gnrc/link_layer/gnrc_mac/internal.c 7.86 KB
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  /*
   * Copyright (C) 2015 Daniel Krebs
   *               2016 INRIA
   *
   * 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     net_gnrc_mac
   * @{
   *
   * @file
   * @brief       Implementation of internal functions of GNRC_MAC
   *
   * @author      Daniel Krebs <github@daniel-krebs.net>
   * @author      Shuguo Zhuo  <shuguo.zhuo@inria.fr>
   * @}
   */
  
  #include <stdbool.h>
  
  #include "net/gnrc.h"
  #include "net/gnrc/mac/internal.h"
  
  #define ENABLE_DEBUG    (0)
  #include "debug.h"
  
  #if ((GNRC_MAC_TX_QUEUE_SIZE != 0) || (GNRC_MAC_RX_QUEUE_SIZE != 0))
  gnrc_priority_pktqueue_node_t *_alloc_pktqueue_node(gnrc_priority_pktqueue_node_t *nodes,
                                                      uint32_t size)
  {
      assert(nodes != NULL);
      assert(size > 0);
  
      /* search for free packet_queue_node */
      for (size_t i = 0; i < size; i++) {
          if ((nodes[i].pkt == NULL) &&
              (nodes[i].next == NULL)) {
              return &nodes[i];
          }
      }
  
      return NULL;
  }
  #endif /* ((GNRC_MAC_TX_QUEUE_SIZE != 0) || (GNRC_MAC_RX_QUEUE_SIZE != 0)) */
  
  #if GNRC_MAC_TX_QUEUE_SIZE != 0
  #if GNRC_MAC_NEIGHBOR_COUNT != 0
  /* Find the neighbor's id based on the given address */
  int _gnrc_mac_find_neighbor(gnrc_mac_tx_t *tx, const uint8_t *dst_addr, int addr_len)
  {
      assert(tx != NULL);
      assert(dst_addr != NULL);
      assert(addr_len > 0);
  
      gnrc_mac_tx_neighbor_t *neighbors;
      neighbors = tx->neighbors;
  
      /* Don't attempt to find broadcast neighbor, so start at index 1 */
      for (int i = 1; i <= (signed)GNRC_MAC_NEIGHBOR_COUNT; i++) {
          if (neighbors[i].l2_addr_len == addr_len) {
              if (memcmp(&(neighbors[i].l2_addr), dst_addr, addr_len) == 0) {
                  return i;
              }
          }
      }
      return -ENOENT;
  }
  
  /* Free first empty queue (neighbor) that is not active */
  int _gnrc_mac_free_neighbor(gnrc_mac_tx_t *tx)
  {
      assert(tx != NULL);
  
      gnrc_mac_tx_neighbor_t *neighbors;
      neighbors = tx->neighbors;
  
      /* Don't attempt to free broadcast neighbor, so start at index 1 */
      for (int i = 1; i <= (signed)GNRC_MAC_NEIGHBOR_COUNT; i++) {
          if ((gnrc_priority_pktqueue_length(&(neighbors[i].queue)) == 0) &&
              (&neighbors[i] != tx->current_neighbor)) {
              /* Mark as free */
              neighbors[i].l2_addr_len = 0;
              return i;
          }
      }
      return -ENOSPC;
  }
  
  /* Allocate first unused queue (neighbor) */
  int _gnrc_mac_alloc_neighbor(gnrc_mac_tx_t *tx)
  {
      assert(tx != NULL);
  
      gnrc_mac_tx_neighbor_t *neighbors;
      neighbors = tx->neighbors;
  
      /* Don't attempt to allocate broadcast neighbor, so start at index 1 */
      for (int i = 1; i <= (signed)GNRC_MAC_NEIGHBOR_COUNT; i++) {
          if (neighbors[i].l2_addr_len == 0) {
              gnrc_priority_pktqueue_init(&(neighbors[i].queue));
              return i;
          }
      }
      return -ENOSPC;
  }
  
  /* Initialize the neighbor */
  void _gnrc_mac_init_neighbor(gnrc_mac_tx_neighbor_t *neighbor, const uint8_t *addr, int len)
  {
      assert(neighbor != NULL);
      assert(addr != NULL);
      assert(len > 0);
  
      neighbor->l2_addr_len = len;
      neighbor->phase = GNRC_MAC_PHASE_MAX;
      memcpy(&(neighbor->l2_addr), addr, len);
  }
  #endif /* GNRC_MAC_NEIGHBOR_COUNT != 0 */
  
  bool gnrc_mac_queue_tx_packet(gnrc_mac_tx_t *tx, uint32_t priority, gnrc_pktsnip_t *pkt)
  {
      assert(tx != NULL);
      assert(pkt != NULL);
  
  #if GNRC_MAC_NEIGHBOR_COUNT == 0
  
      gnrc_priority_pktqueue_node_t *node;
      node = _alloc_pktqueue_node(tx->_queue_nodes, GNRC_MAC_TX_QUEUE_SIZE);
  
      if (node) {
          gnrc_priority_pktqueue_node_init(node, priority, pkt);
          gnrc_priority_pktqueue_push(&tx->queue, node);
          return true;
      }
  
      DEBUG("[gnrc_mac-int] Can't push to TX queue, no entries left\n");
      return false;
  
  #else
  
      gnrc_mac_tx_neighbor_t *neighbor;
      int neighbor_id;
  
      /* Check whether the packet it for broadcast or multicast */
      if (gnrc_netif_hdr_get_flag(pkt) &
          (GNRC_NETIF_HDR_FLAGS_MULTICAST | GNRC_NETIF_HDR_FLAGS_BROADCAST)) {
          /* Broadcast/multicast queue is neighbor 0 by definition */
          neighbor_id = 0;
          neighbor = &tx->neighbors[neighbor_id];
  
      }
      else {
          uint8_t *addr;
          int addr_len;
          bool neighbor_known = true;
  
          /* Get destination address of packet */
          addr_len = gnrc_netif_hdr_get_dstaddr(pkt, &addr);
          if (addr_len <= 0) {
              DEBUG("[gnrc_mac-int] Packet has no destination address\n");
              return false;
          }
  
          /* Search for existing queue for destination */
          neighbor_id = _gnrc_mac_find_neighbor(tx, addr, addr_len);
  
          /* neighbor node doesn't have a queue yet */
          if (neighbor_id < 0) {
              neighbor_known = false;
  
              /* Try to allocate neighbor entry */
              neighbor_id = _gnrc_mac_alloc_neighbor(tx);
  
              /* No neighbor entries left */
              if (neighbor_id < 0) {
                  DEBUG("[gnrc_mac-int] No neighbor entries left, maybe increase "
                        "GNRC_MAC_NEIGHBOR_COUNT for better performance\n");
  
                  /* Try to free an unused queue */
                  neighbor_id = _gnrc_mac_free_neighbor(tx);
  
                  /* All queues are in use, so reject */
                  if (neighbor_id < 0) {
                      DEBUG("[gnrc_mac-int] Couldn't allocate tx queue for packet\n");
                      return false;
                  }
              }
          }
  
          neighbor = &tx->neighbors[neighbor_id];
  
          if (!neighbor_known) {
              _gnrc_mac_init_neighbor(neighbor, addr, addr_len);
          }
      }
  
      gnrc_priority_pktqueue_node_t *node;
      node = _alloc_pktqueue_node(tx->_queue_nodes, GNRC_MAC_TX_QUEUE_SIZE);
      if (node) {
          gnrc_priority_pktqueue_node_init(node, priority, pkt);
          gnrc_priority_pktqueue_push(&neighbor->queue, node);
          DEBUG("[gnrc_mac-int] Queuing pkt to neighbor #%d\n", neighbor_id);
          return true;
      }
  
      DEBUG("[gnrc_mac-int] Can't push to neighbor #%d's queue, no entries left\n",
            neighbor_id);
      return false;
  
  #endif  /* GNRC_MAC_NEIGHBOR_COUNT == 0 */
  }
  #endif  /* GNRC_MAC_TX_QUEUE_SIZE != 0 */
  
  #if GNRC_MAC_RX_QUEUE_SIZE != 0
  bool gnrc_mac_queue_rx_packet(gnrc_mac_rx_t *rx, uint32_t priority, gnrc_pktsnip_t *pkt)
  {
      assert(rx != NULL);
      assert(pkt != NULL);
  
      gnrc_priority_pktqueue_node_t *node;
      node = _alloc_pktqueue_node(rx->_queue_nodes, GNRC_MAC_RX_QUEUE_SIZE);
  
      if (node) {
          gnrc_priority_pktqueue_node_init(node, priority, pkt);
          gnrc_priority_pktqueue_push(&rx->queue, node);
          return true;
      }
  
      DEBUG("[gnrc_mac] Can't push RX packet @ %p, no entries left\n", pkt);
      return false;
  }
  #endif /* GNRC_MAC_RX_QUEUE_SIZE != 0 */
  
  #if GNRC_MAC_DISPATCH_BUFFER_SIZE != 0
  void gnrc_mac_dispatch(gnrc_mac_rx_t *rx)
  {
      assert(rx != NULL);
  
      for (unsigned i = 0; i < GNRC_MAC_DISPATCH_BUFFER_SIZE; i++) {
          if (rx->dispatch_buffer[i]) {
  #ifdef MODULE_GNRC_LWMAC
              /* save pointer to netif header */
              gnrc_pktsnip_t *netif = rx->dispatch_buffer[i]->next->next;
  
              /* remove lwmac header */
              rx->dispatch_buffer[i]->next->next = NULL;
              gnrc_pktbuf_release(rx->dispatch_buffer[i]->next);
  
              /* make append netif header after payload again */
              rx->dispatch_buffer[i]->next = netif;
  #endif
              if (!gnrc_netapi_dispatch_receive(rx->dispatch_buffer[i]->type,
                                                GNRC_NETREG_DEMUX_CTX_ALL,
                                                rx->dispatch_buffer[i])) {
                  DEBUG("Unable to forward packet of type %i\n", buffer[i]->type);
                  gnrc_pktbuf_release(rx->dispatch_buffer[i]);
              }
              rx->dispatch_buffer[i] = NULL;
          }
      }
  }
  #endif /* GNRC_MAC_DISPATCH_BUFFER_SIZE != 0 */