Merge pull request #15943 from jia200x/pr/gnrc_lorawan_channel_mask

net/gnrc_lorawan: implement channel mask support

sys/include/net/gnrc/lorawan.h

@@ -284,6 +284,18 @@ void gnrc_lorawan_mlme_confirm(gnrc_lorawan_t *mac, mlme_confirm_t *confirm);
  */
 netdev_t *gnrc_lorawan_get_netdev(gnrc_lorawan_t *mac);
 
+/**
+ * @brief Set the channel mask in order to enable or disable LoRaWAN channels
+ *
+ * @param[in] mac pointer to the MAC descriptor
+ * @param[in] channel_mask the channel mask. LSB maps to channel 0
+ *
+ * @return 0 on success
+ * @return -EINVAL if @p channel_mask is zero or if the channel mask tries to
+ *         enable an undefined channel
+ */
+int gnrc_lorawan_phy_set_channel_mask(gnrc_lorawan_t *mac, uint16_t channel_mask);
+
 #ifdef __cplusplus
 }
 #endif

sys/net/gnrc/link_layer/lorawan/gnrc_lorawan_mlme.c

@@ -144,6 +144,7 @@ void gnrc_lorawan_mlme_process_join(gnrc_lorawan_t *mac, uint8_t *data,
         gnrc_lorawan_process_cflist(mac, out + sizeof(lorawan_join_accept_t) - 1);
     }
 
+    DEBUG("gnrc_lorawan: Channel mask is %04x\n", mac->channel_mask);
     mac->mlme.activation = MLME_ACTIVATION_OTAA;
     status = GNRC_LORAWAN_REQ_STATUS_SUCCESS;
 

sys/net/gnrc/link_layer/lorawan/gnrc_lorawan_region.c

@@ -13,6 +13,8 @@
  * @author  José Ignacio Alamos <jose.alamos@haw-hamburg.de>
  */
 #include "kernel_defines.h"
+#include "bitarithm.h"
+#include "random.h"
 #include "net/gnrc/lorawan/region.h"
 
 #define ENABLE_DEBUG 0
@@ -62,35 +64,27 @@ uint8_t gnrc_lorawan_rx1_get_dr_offset(uint8_t dr_up, uint8_t dr_offset)
 }
 #endif
 
-static size_t _get_num_used_channels(gnrc_lorawan_t *mac)
+int gnrc_lorawan_phy_set_channel_mask(gnrc_lorawan_t *mac, uint16_t channel_mask)
 {
-    size_t count = 0;
+    if (!channel_mask) {
+        return -EINVAL;
+    }
 
-    for (unsigned i = 0; i < GNRC_LORAWAN_MAX_CHANNELS; i++) {
-        if (mac->channel[i]) {
-            count++;
+    for (int n = channel_mask, i = 0; n; n = n >> 1, i++) {
+        if ((n & 0x1) && !mac->channel[i]) {
+           return -EINVAL;
         }
     }
-    return count;
-}
 
-static uint32_t _get_nth_channel(gnrc_lorawan_t *mac, size_t n)
-{
-    int i = 0;
-    uint32_t channel = 0;
-
-    while (n) {
-        if (mac->channel[i]) {
-            n--;
-            channel = mac->channel[i];
-            i++;
-        }
-    }
-    return channel;
+    mac->channel_mask = channel_mask;
+    return 0;
 }
 
 void gnrc_lorawan_channels_init(gnrc_lorawan_t *mac)
 {
+    /* We set the channel mask for the default channels and populate from the list */
+    mac->channel_mask = UINT16_MAX >> (16 - GNRC_LORAWAN_DEFAULT_CHANNELS_NUMOF);
+
     for (unsigned i = 0; i < GNRC_LORAWAN_DEFAULT_CHANNELS_NUMOF; i++) {
         mac->channel[i] = gnrc_lorawan_default_channels[i];
         DEBUG("gnrc_lorawan_region: Mac -> Channel %u %" PRIu32 " \n", i, mac->channel[i]);
@@ -104,14 +98,15 @@ void gnrc_lorawan_channels_init(gnrc_lorawan_t *mac)
 
 uint32_t gnrc_lorawan_pick_channel(gnrc_lorawan_t *mac)
 {
-    netdev_t *netdev = gnrc_lorawan_get_netdev(mac);
-    uint32_t random_number;
+    uint8_t index = 0;
 
-    netdev->driver->get(netdev, NETOPT_RANDOM, &random_number,
-                        sizeof(random_number));
+    uint8_t random_number = random_uint32_range(0, bitarithm_bits_set(mac->channel_mask));
+    unsigned state = mac->channel_mask;
 
-    return _get_nth_channel(mac,
-                            1 + (random_number % _get_num_used_channels(mac)));
+    for (int i = 0; i < random_number; i++) {
+        state = bitarithm_test_and_clear(state, &index);
+    }
+    return mac->channel[index];
 }
 
 void gnrc_lorawan_process_cflist(gnrc_lorawan_t *mac, uint8_t *cflist)
@@ -122,6 +117,7 @@ void gnrc_lorawan_process_cflist(gnrc_lorawan_t *mac, uint8_t *cflist)
         cl.u32 = 0;
         memcpy(&cl, cflist, GNRC_LORAWAN_CFLIST_ENTRY_SIZE);
         mac->channel[i] = byteorder_ltohl(cl) * 100;
+        mac->channel_mask |= 1 << i;
         cflist += GNRC_LORAWAN_CFLIST_ENTRY_SIZE;
         DEBUG("gnrc_lorawan_region: Mac -> Channel %u %" PRIu32 " \n", i, mac->channel[i]);
     }

sys/net/gnrc/link_layer/lorawan/include/gnrc_lorawan_internal.h

@@ -185,6 +185,7 @@ typedef struct {
     uint8_t *nwkskey;                               /**< pointer to Network SKey buffer */
     uint8_t *appskey;                               /**< pointer to Application SKey buffer */
     uint32_t channel[GNRC_LORAWAN_MAX_CHANNELS];    /**< channel array */
+    uint16_t channel_mask;                          /**< channel mask */
     uint32_t toa;                                   /**< Time on Air of the last transmission */
     int busy;                                       /**< MAC busy  */
     int shutdown_req;                               /**< MAC Shutdown request */