Fix #722: don't allow LMIC_setupChannel() to change default channels.

src/lmic/lmic.h

@@ -660,6 +660,9 @@ bit_t LMIC_enableChannel(u1_t channel);
 bit_t LMIC_disableSubBand(u1_t band);
 bit_t LMIC_selectSubBand(u1_t band);
 
+//! \brief get the number of (fixed) default channels before the progammable channels.
+u1_t  LMIC_queryNumDefaultChannels(void);
+
 void  LMIC_setDrTxpow   (dr_t dr, s1_t txpow);  // set default/start DR/txpow
 void  LMIC_setAdrMode   (bit_t enabled);        // set ADR mode (if mobile turn off)
 

src/lmic/lmic_as923.c

@@ -226,17 +226,29 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
         return 1;
 }
 
+
+///
+/// \brief query number of default channels.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return NUM_DEFAULT_CHANNELS;
+}
+
+///
+/// \brief LMIC_setupChannel for EU 868
+///
+/// \note according to LoRaWAN 1.3 section 5.6, "the acceptable range
+///     for **ChIndex** is N to 16", where N is our \c NUM_DEFAULT_CHANNELS.
+///     This routine is used internally for MAC commands, so we enforce
+///     this for the extenal API as well.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         // zero the band bits in freq, just in case.
         freq &= ~3;
 
         if (chidx < NUM_DEFAULT_CHANNELS) {
-                // can't disable a default channel.
-                if (freq == 0)
-                        return 0;
-                // can't change a default channel.
-                else if (freq != (LMIC.channelFreq[chidx] & ~3))
-                        return 0;
+                // can't do anything to a default channel.
+                return 0;
         }
         bit_t fEnable = (freq != 0);
         if (chidx >= MAX_CHANNELS)

src/lmic/lmic_au915.c

@@ -144,7 +144,24 @@ u4_t LMICau915_convFreq(xref2cu1_t ptr) {
         return freq;
 }
 
-// au915: no support for xchannels.
+///
+/// \brief query number of default channels.
+///
+/// \note
+///     For AU, we have no programmable channels; all channels
+///     are fixed. Return the total channel count.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return 64 + 8;
+}
+
+
+///
+/// \brief LMIC_setupChannel for AU915
+///
+/// \note there are no progammable channels for US915, so this API
+///     always returns FALSE.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         LMIC_API_PARAMETER(chidx);
         LMIC_API_PARAMETER(freq);

src/lmic/lmic_eu868.c

@@ -140,17 +140,28 @@ static CONST_TABLE(u4_t, bandAssignments)[] = {
   865000000 /* .. 868400000 */    | BAND_CENTI,
 };
 
+///
+/// \brief query number of default channels.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return NUM_DEFAULT_CHANNELS;
+}
+
+///
+/// \brief LMIC_setupChannel for EU 868
+///
+/// \note according to LoRaWAN 1.0.3 section 5.6, "the acceptable range
+///     for **ChIndex** is N to 16", where N is our \c NUM_DEFAULT_CHANNELS.
+///     This routine is used internally for MAC commands, so we enforce
+///     this for the extenal API as well.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         // zero the band bits in freq, just in case.
         freq &= ~3;
 
         if (chidx < NUM_DEFAULT_CHANNELS) {
-                // can't disable a default channel.
-                if (freq == 0)
-                        return 0;
-                // can't change a default channel.
-                else if (freq != (LMIC.channelFreq[chidx] & ~3))
-                        return 0;
+                // can't do anything to a default channel.
+                return 0;
         }
         bit_t fEnable = (freq != 0);
         if (chidx >= MAX_CHANNELS)

src/lmic/lmic_in866.c

@@ -134,17 +134,27 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
         return 1;
 }
 
+///
+/// \brief query number of default channels.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return NUM_DEFAULT_CHANNELS;
+}
+
+///
+/// \brief LMIC_setupChannel for IN region
+///
+/// \note according to LoRaWAN 1.3 section 5.6, "the acceptable range
+///     for **ChIndex** is N to 16", where N is our \c NUM_DEFAULT_CHANNELS.
+///     This routine is used internally for MAC commands, so we enforce
+///     this for the extenal API as well.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         // zero the band bits in freq, just in case.
         freq &= ~3;
 
         if (chidx < NUM_DEFAULT_CHANNELS) {
-                // can't disable a default channel.
-                if (freq == 0)
-                        return 0;
-                // can't change a default channel.
-                else if (freq != (LMIC.channelFreq[chidx] & ~3))
-                        return 0;
+                return 0;
         }
         bit_t fEnable = (freq != 0);
         if (chidx >= MAX_CHANNELS)

src/lmic/lmic_kr920.c

@@ -145,17 +145,28 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
         return 1;
 }
 
+///
+/// \brief query number of default channels.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return NUM_DEFAULT_CHANNELS;
+}
+
+///
+/// \brief LMIC_setupChannel for KR920
+///
+/// \note according to LoRaWAN 1.3 section 5.6, "the acceptable range
+///     for **ChIndex** is N to 16", where N is our \c NUM_DEFAULT_CHANNELS.
+///     This routine is used internally for MAC commands, so we enforce
+///     this for the extenal API as well.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         // zero the band bits in freq, just in case.
         freq &= ~3;
 
         if (chidx < NUM_DEFAULT_CHANNELS) {
-                // can't disable a default channel.
-                if (freq == 0)
-                        return 0;
                 // can't change a default channel.
-                else if (freq != (LMIC.channelFreq[chidx] & ~3))
-                        return 0;
+                return 0;
         }
         bit_t fEnable = (freq != 0);
         if (chidx >= MAX_CHANNELS)

src/lmic/lmic_us915.c

@@ -99,6 +99,22 @@ u4_t LMICus915_convFreq(xref2cu1_t ptr) {
         return freq;
 }
 
+///
+/// \brief query number of default channels.
+///
+///     For US, we have no programmable channels; all channels
+///     are fixed. Return the total channel count.
+///
+u1_t LMIC_queryNumDefaultChannels() {
+        return 64 + 8;
+}
+
+///
+/// \brief LMIC_setupChannel for US915
+///
+/// \note there are no progammable channels for US915, so this API
+///     always returns FALSE.
+///
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
         LMIC_API_PARAMETER(chidx);
         LMIC_API_PARAMETER(freq);