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lmic.c
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/*
* Copyright (c) 2014-2016 IBM Corporation.
* All rights reserved.
*
* Copyright (c) 2016-2018 MCCI Corporation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the <organization> nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
//! \file
#define LMIC_DR_LEGACY 0
#include "lmic_bandplan.h"
#if defined(DISABLE_BEACONS) && !defined(DISABLE_PING)
#error Ping needs beacon tracking
#endif
DEFINE_LMIC;
// Fwd decls.
static void engineUpdate(void);
#if !defined(DISABLE_BEACONS)
static void startScan (void);
#endif
static inline void initTxrxFlags(const char *func, u1_t mask) {
LMIC_DEBUG2_PARAMETER(func);
#if LMIC_DEBUG_LEVEL > 1
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": %s txrxFlags %#02x --> %02x\n", os_getTime(), func, LMIC.txrxFlags, mask);
#endif
LMIC.txrxFlags = mask;
}
static inline void orTxrxFlags(const char *func, u1_t mask) {
initTxrxFlags(func, LMIC.txrxFlags | mask);
}
// ================================================================================
// BEG OS - default implementations for certain OS suport functions
#if !defined(HAS_os_calls)
#if !defined(os_rlsbf2)
u2_t os_rlsbf2 (xref2cu1_t buf) {
return (u2_t)((u2_t)buf[0] | ((u2_t)buf[1]<<8));
}
#endif
#if !defined(os_rlsbf4)
u4_t os_rlsbf4 (xref2cu1_t buf) {
return (u4_t)((u4_t)buf[0] | ((u4_t)buf[1]<<8) | ((u4_t)buf[2]<<16) | ((u4_t)buf[3]<<24));
}
#endif
#if !defined(os_rmsbf4)
u4_t os_rmsbf4 (xref2cu1_t buf) {
return (u4_t)((u4_t)buf[3] | ((u4_t)buf[2]<<8) | ((u4_t)buf[1]<<16) | ((u4_t)buf[0]<<24));
}
#endif
#if !defined(os_wlsbf2)
void os_wlsbf2 (xref2u1_t buf, u2_t v) {
buf[0] = v;
buf[1] = v>>8;
}
#endif
#if !defined(os_wlsbf4)
void os_wlsbf4 (xref2u1_t buf, u4_t v) {
buf[0] = v;
buf[1] = v>>8;
buf[2] = v>>16;
buf[3] = v>>24;
}
#endif
#if !defined(os_wmsbf4)
void os_wmsbf4 (xref2u1_t buf, u4_t v) {
buf[3] = v;
buf[2] = v>>8;
buf[1] = v>>16;
buf[0] = v>>24;
}
#endif
#if !defined(os_getBattLevel)
u1_t os_getBattLevel (void) {
return MCMD_DEVS_BATT_NOINFO;
}
#endif
#if !defined(os_crc16)
// New CRC-16 CCITT(XMODEM) checksum for beacons:
u2_t os_crc16 (xref2cu1_t data, uint len) {
u2_t remainder = 0;
u2_t polynomial = 0x1021;
for( uint i = 0; i < len; i++ ) {
remainder ^= data[i] << 8;
for( u1_t bit = 8; bit > 0; bit--) {
if( (remainder & 0x8000) )
remainder = (remainder << 1) ^ polynomial;
else
remainder <<= 1;
}
}
return remainder;
}
#endif
#endif // !HAS_os_calls
// END OS - default implementations for certain OS suport functions
// ================================================================================
// ================================================================================
// BEG AES
static void micB0 (u4_t devaddr, u4_t seqno, int dndir, int len) {
os_clearMem(AESaux,16);
AESaux[0] = 0x49;
AESaux[5] = dndir?1:0;
AESaux[15] = len;
os_wlsbf4(AESaux+ 6,devaddr);
os_wlsbf4(AESaux+10,seqno);
}
static int aes_verifyMic (xref2cu1_t key, u4_t devaddr, u4_t seqno, int dndir, xref2u1_t pdu, int len) {
micB0(devaddr, seqno, dndir, len);
os_copyMem(AESkey,key,16);
return os_aes(AES_MIC, pdu, len) == os_rmsbf4(pdu+len);
}
static void aes_appendMic (xref2cu1_t key, u4_t devaddr, u4_t seqno, int dndir, xref2u1_t pdu, int len) {
micB0(devaddr, seqno, dndir, len);
os_copyMem(AESkey,key,16);
// MSB because of internal structure of AES
os_wmsbf4(pdu+len, os_aes(AES_MIC, pdu, len));
}
static void aes_appendMic0 (xref2u1_t pdu, int len) {
os_getDevKey(AESkey);
os_wmsbf4(pdu+len, os_aes(AES_MIC|AES_MICNOAUX, pdu, len)); // MSB because of internal structure of AES
}
static int aes_verifyMic0 (xref2u1_t pdu, int len) {
os_getDevKey(AESkey);
return os_aes(AES_MIC|AES_MICNOAUX, pdu, len) == os_rmsbf4(pdu+len);
}
static void aes_encrypt (xref2u1_t pdu, int len) {
os_getDevKey(AESkey);
os_aes(AES_ENC, pdu, len);
}
static void aes_cipher (xref2cu1_t key, u4_t devaddr, u4_t seqno, int dndir, xref2u1_t payload, int len) {
if( len <= 0 )
return;
os_clearMem(AESaux, 16);
AESaux[0] = AESaux[15] = 1; // mode=cipher / dir=down / block counter=1
AESaux[5] = dndir?1:0;
os_wlsbf4(AESaux+ 6,devaddr);
os_wlsbf4(AESaux+10,seqno);
os_copyMem(AESkey,key,16);
os_aes(AES_CTR, payload, len);
}
static void aes_sessKeys (u2_t devnonce, xref2cu1_t artnonce, xref2u1_t nwkkey, xref2u1_t artkey) {
os_clearMem(nwkkey, 16);
nwkkey[0] = 0x01;
os_copyMem(nwkkey+1, artnonce, LEN_ARTNONCE+LEN_NETID);
os_wlsbf2(nwkkey+1+LEN_ARTNONCE+LEN_NETID, devnonce);
os_copyMem(artkey, nwkkey, 16);
artkey[0] = 0x02;
os_getDevKey(AESkey);
os_aes(AES_ENC, nwkkey, 16);
os_getDevKey(AESkey);
os_aes(AES_ENC, artkey, 16);
}
// END AES
// ================================================================================
// ================================================================================
// BEG LORA
static CONST_TABLE(u1_t, SENSITIVITY)[7][3] = {
// ------------bw----------
// 125kHz 250kHz 500kHz
{ 141-109, 141-109, 141-109 }, // FSK
{ 141-127, 141-124, 141-121 }, // SF7
{ 141-129, 141-126, 141-123 }, // SF8
{ 141-132, 141-129, 141-126 }, // SF9
{ 141-135, 141-132, 141-129 }, // SF10
{ 141-138, 141-135, 141-132 }, // SF11
{ 141-141, 141-138, 141-135 } // SF12
};
int getSensitivity (rps_t rps) {
return -141 + TABLE_GET_U1_TWODIM(SENSITIVITY, getSf(rps), getBw(rps));
}
ostime_t calcAirTime (rps_t rps, u1_t plen) {
u1_t bw = getBw(rps); // 0,1,2 = 125,250,500kHz
u1_t sf = getSf(rps); // 0=FSK, 1..6 = SF7..12
if( sf == FSK ) {
return (plen+/*preamble*/5+/*syncword*/3+/*len*/1+/*crc*/2) * /*bits/byte*/8
* (s4_t)OSTICKS_PER_SEC / /*kbit/s*/50000;
}
u1_t sfx = 4*(sf+(7-SF7));
u1_t q = sfx - (sf >= SF11 ? 8 : 0);
int tmp = 8*plen - sfx + 28 + (getNocrc(rps)?0:16) - (getIh(rps)?20:0);
if( tmp > 0 ) {
tmp = (tmp + q - 1) / q;
tmp *= getCr(rps)+5;
tmp += 8;
} else {
tmp = 8;
}
tmp = (tmp<<2) + /*preamble*/49 /* 4 * (8 + 4.25) */;
// bw = 125000 = 15625 * 2^3
// 250000 = 15625 * 2^4
// 500000 = 15625 * 2^5
// sf = 7..12
//
// osticks = tmp * OSTICKS_PER_SEC * 1<<sf / bw
//
// 3 => counter reduced divisor 125000/8 => 15625
// 2 => counter 2 shift on tmp
sfx = sf+(7-SF7) - (3+2) - bw;
int div = 15625;
if( sfx > 4 ) {
// prevent 32bit signed int overflow in last step
div >>= sfx-4;
sfx = 4;
}
// Need 32bit arithmetic for this last step
return (((ostime_t)tmp << sfx) * OSTICKS_PER_SEC + div/2) / div;
}
// END LORA
// ================================================================================
// Adjust DR for TX retries
// - indexed by retry count
// - return steps to lower DR
static CONST_TABLE(u1_t, DRADJUST)[2+TXCONF_ATTEMPTS] = {
// normal frames - 1st try / no retry
0,
// confirmed frames
0,0,1,0,1,0,1,0,0
};
// Table below defines the size of one symbol as
// symtime = 256us * 2^T(sf,bw)
// 256us is called one symunit.
// SF:
// BW: |__7___8___9__10__11__12
// 125kHz | 2 3 4 5 6 7
// 250kHz | 1 2 3 4 5 6
// 500kHz | 0 1 2 3 4 5
//
#if !defined(DISABLE_BEACONS)
static ostime_t calcRxWindow (u1_t secs, dr_t dr) {
ostime_t rxoff, err;
if( secs==0 ) {
// aka 128 secs (next becaon)
rxoff = LMIC.drift;
err = LMIC.lastDriftDiff;
} else {
// scheduled RX window within secs into current beacon period
rxoff = (LMIC.drift * (ostime_t)secs) >> BCN_INTV_exp;
err = (LMIC.lastDriftDiff * (ostime_t)secs) >> BCN_INTV_exp;
}
u1_t rxsyms = MINRX_SYMS;
err += (ostime_t)LMIC.maxDriftDiff * LMIC.missedBcns;
LMIC.rxsyms = MINRX_SYMS + (err / dr2hsym(dr));
return (rxsyms-PAMBL_SYMS) * dr2hsym(dr) + rxoff;
}
// Setup beacon RX parameters assuming we have an error of ms (aka +/-(ms/2))
static void calcBcnRxWindowFromMillis (u1_t ms, bit_t ini) {
if( ini ) {
LMIC.drift = 0;
LMIC.maxDriftDiff = 0;
LMIC.missedBcns = 0;
LMIC.bcninfo.flags |= BCN_NODRIFT|BCN_NODDIFF;
}
ostime_t hsym = dr2hsym(DR_BCN);
LMIC.bcnRxsyms = MINRX_SYMS + ms2osticksCeil(ms) / hsym;
LMIC.bcnRxtime = LMIC.bcninfo.txtime + BCN_INTV_osticks - (LMIC.bcnRxsyms-PAMBL_SYMS) * hsym;
}
#endif // !DISABLE_BEACONS
#if !defined(DISABLE_PING)
// Setup scheduled RX window (ping/multicast slot)
static void rxschedInit (xref2rxsched_t rxsched) {
os_clearMem(AESkey,16);
os_clearMem(LMIC.frame+8,8);
os_wlsbf4(LMIC.frame, LMIC.bcninfo.time);
os_wlsbf4(LMIC.frame+4, LMIC.devaddr);
os_aes(AES_ENC,LMIC.frame,16);
u1_t intvExp = rxsched->intvExp;
ostime_t off = os_rlsbf2(LMIC.frame) & (0x0FFF >> (7 - intvExp)); // random offset (slot units)
rxsched->rxbase = (LMIC.bcninfo.txtime +
BCN_RESERVE_osticks +
ms2osticks(BCN_SLOT_SPAN_ms * off)); // random offset osticks
rxsched->slot = 0;
rxsched->rxtime = rxsched->rxbase - calcRxWindow(/*secs BCN_RESERVE*/2+(1<<intvExp),rxsched->dr);
rxsched->rxsyms = LMIC.rxsyms;
}
static bit_t rxschedNext (xref2rxsched_t rxsched, ostime_t cando) {
again:
if( rxsched->rxtime - cando >= 0 )
return 1;
u1_t slot;
if( (slot=rxsched->slot) >= 128 )
return 0;
u1_t intv = 1<<rxsched->intvExp;
if( (rxsched->slot = (slot += (intv))) >= 128 )
return 0;
rxsched->rxtime = rxsched->rxbase
+ ((BCN_WINDOW_osticks * (ostime_t)slot) >> BCN_INTV_exp)
- calcRxWindow(/*secs BCN_RESERVE*/2+slot+intv,rxsched->dr);
rxsched->rxsyms = LMIC.rxsyms;
goto again;
}
#endif // !DISABLE_PING)
ostime_t LMICcore_rndDelay (u1_t secSpan) {
u2_t r = os_getRndU2();
ostime_t delay = r;
if( delay > OSTICKS_PER_SEC )
delay = r % (u2_t)OSTICKS_PER_SEC;
if( secSpan > 0 )
delay += ((u1_t)r % secSpan) * OSTICKS_PER_SEC;
return delay;
}
static void txDelay (ostime_t reftime, u1_t secSpan) {
reftime += LMICcore_rndDelay(secSpan);
if( LMIC.globalDutyRate == 0 || (reftime - LMIC.globalDutyAvail) > 0 ) {
LMIC.globalDutyAvail = reftime;
LMIC.opmode |= OP_RNDTX;
}
}
void LMICcore_setDrJoin (u1_t reason, u1_t dr) {
LMIC_EV_PARAMETER(reason);
EV(drChange, INFO, (e_.reason = reason,
e_.deveui = MAIN::CDEV->getEui(),
e_.dr = dr|DR_PAGE,
e_.txpow = LMIC.adrTxPow,
e_.prevdr = LMIC.datarate|DR_PAGE,
e_.prevtxpow = LMIC.adrTxPow));
LMIC.datarate = dr;
DO_DEVDB(LMIC.datarate,datarate);
}
static void setDrTxpow (u1_t reason, u1_t dr, s1_t pow) {
LMIC_EV_PARAMETER(reason);
EV(drChange, INFO, (e_.reason = reason,
e_.deveui = MAIN::CDEV->getEui(),
e_.dr = dr|DR_PAGE,
e_.txpow = pow,
e_.prevdr = LMIC.datarate|DR_PAGE,
e_.prevtxpow = LMIC.adrTxPow));
if( pow != KEEP_TXPOW )
LMIC.adrTxPow = pow;
if( LMIC.datarate != dr ) {
LMIC.datarate = dr;
DO_DEVDB(LMIC.datarate,datarate);
LMIC.opmode |= OP_NEXTCHNL;
}
}
#if !defined(DISABLE_PING)
void LMIC_stopPingable (void) {
LMIC.opmode &= ~(OP_PINGABLE|OP_PINGINI);
}
void LMIC_setPingable (u1_t intvExp) {
// Change setting
LMIC.ping.intvExp = (intvExp & 0x7);
LMIC.opmode |= OP_PINGABLE;
// App may call LMIC_enableTracking() explicitely before
// Otherwise tracking is implicitly enabled here
if( (LMIC.opmode & (OP_TRACK|OP_SCAN)) == 0 && LMIC.bcninfoTries == 0 )
LMIC_enableTracking(0);
}
#endif // !DISABLE_PING
static void runEngineUpdate (xref2osjob_t osjob) {
LMIC_API_PARAMETER(osjob);
engineUpdate();
}
static void reportEvent (ev_t ev) {
EV(devCond, INFO, (e_.reason = EV::devCond_t::LMIC_EV,
e_.eui = MAIN::CDEV->getEui(),
e_.info = ev));
ON_LMIC_EVENT(ev);
engineUpdate();
}
static void runReset (xref2osjob_t osjob) {
LMIC_API_PARAMETER(osjob);
// Disable session
LMIC_reset();
#if !defined(DISABLE_JOIN)
LMIC_startJoining();
#endif // !DISABLE_JOIN
reportEvent(EV_RESET);
}
static void stateJustJoined (void) {
LMIC.seqnoDn = LMIC.seqnoUp = 0;
LMIC.rejoinCnt = 0;
LMIC.dnConf = LMIC.adrChanged = LMIC.ladrAns = LMIC.devsAns = 0;
#if !defined(DISABLE_MCMD_SNCH_REQ)
LMIC.snchAns = 0;
#endif
#if !defined(DISABLE_MCMD_DN2P_SET)
LMIC.dn2Ans = 0;
#endif
LMIC.moreData = 0;
#if !defined(DISABLE_MCMD_DCAP_REQ)
LMIC.dutyCapAns = 0;
#endif
#if !defined(DISABLE_MCMD_PING_SET) && !defined(DISABLE_PING)
LMIC.pingSetAns = 0;
#endif
LMIC.upRepeat = 0;
LMIC.adrAckReq = LINK_CHECK_INIT;
LMIC.dn2Dr = DR_DNW2;
LMIC.dn2Freq = FREQ_DNW2;
#if !defined(DISABLE_BEACONS)
LMIC.bcnChnl = CHNL_BCN;
#endif
#if !defined(DISABLE_PING)
LMIC.ping.freq = FREQ_PING;
LMIC.ping.dr = DR_PING;
#endif
}
// ================================================================================
// Decoding frames
#if !defined(DISABLE_BEACONS)
// Decode beacon - do not overwrite bcninfo unless we have a match!
static int decodeBeacon (void) {
ASSERT(LMIC.dataLen == LEN_BCN); // implicit header RX guarantees this
xref2u1_t d = LMIC.frame;
if(! LMICbandplan_isValidBeacon1(d))
return 0; // first (common) part fails CRC check
// First set of fields is ok
u4_t bcnnetid = os_rlsbf4(&d[OFF_BCN_NETID]) & 0xFFFFFF;
if( bcnnetid != LMIC.netid )
return -1; // not the beacon we're looking for
LMIC.bcninfo.flags &= ~(BCN_PARTIAL|BCN_FULL);
// Match - update bcninfo structure
LMIC.bcninfo.snr = LMIC.snr;
LMIC.bcninfo.rssi = LMIC.rssi;
LMIC.bcninfo.txtime = LMIC.rxtime - AIRTIME_BCN_osticks;
LMIC.bcninfo.time = os_rlsbf4(&d[OFF_BCN_TIME]);
LMIC.bcninfo.flags |= BCN_PARTIAL;
// Check 2nd set
if( os_rlsbf2(&d[OFF_BCN_CRC2]) != os_crc16(d,OFF_BCN_CRC2) )
return 1;
// Second set of fields is ok
LMIC.bcninfo.lat = (s4_t)os_rlsbf4(&d[OFF_BCN_LAT-1]) >> 8; // read as signed 24-bit
LMIC.bcninfo.lon = (s4_t)os_rlsbf4(&d[OFF_BCN_LON-1]) >> 8; // ditto
LMIC.bcninfo.info = d[OFF_BCN_INFO];
LMIC.bcninfo.flags |= BCN_FULL;
return 2;
}
#endif // !DISABLE_BEACONS
// scan mac commands starting at opts[] for olen, return count of bytes consumed.
static int
scan_mac_cmds(
const uint8_t *opts,
int olen
) {
int oidx = 0;
while( oidx < olen ) {
switch( opts[oidx] ) {
case MCMD_LCHK_ANS: {
//int gwmargin = opts[oidx+1];
//int ngws = opts[oidx+2];
oidx += 3;
continue;
}
case MCMD_LADR_REQ: {
u1_t p1 = opts[oidx+1]; // txpow + DR
u2_t chmap = os_rlsbf2(&opts[oidx+2]);// list of enabled channels
u1_t chpage = opts[oidx+4] & MCMD_LADR_CHPAGE_MASK; // channel page
u1_t uprpt = opts[oidx+4] & MCMD_LADR_REPEAT_MASK; // up repeat count
oidx += 5;
// TODO([email protected]): LoRaWAN 1.1 requires us to process multiple
// LADR requests, and only update if all pass. So this should check
// ladrAns == 0, and only initialize if so. Need to repeat ACKs, so
// we need to count the number we see.
LMIC.ladrAns = 0x80 | // Include an answer into next frame up
MCMD_LADR_ANS_POWACK | MCMD_LADR_ANS_CHACK | MCMD_LADR_ANS_DRACK;
if( !LMICbandplan_mapChannels(chpage, chmap) )
LMIC.ladrAns &= ~MCMD_LADR_ANS_CHACK;
dr_t dr = (dr_t)(p1>>MCMD_LADR_DR_SHIFT);
if( !validDR(dr) ) {
LMIC.ladrAns &= ~MCMD_LADR_ANS_DRACK;
EV(specCond, ERR, (e_.reason = EV::specCond_t::BAD_MAC_CMD,
e_.eui = MAIN::CDEV->getEui(),
e_.info = Base::lsbf4(&d[pend]),
e_.info2 = Base::msbf4(&opts[oidx-4])));
}
// TODO([email protected]): see above; this needs to move outside the
// txloop. And we need to have "consistent" answers for the block
// of contiguous commands (whatever that means), and ignore the
// data rate, NbTrans (uprpt) and txPow until the last one.
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": LinkAdrReq: p1:%02x chmap:%04x chpage:%02x uprt:%02x ans:%02x\n",
os_getTime(), p1, chmap, chpage, uprpt, LMIC.ladrAns
);
#endif /* LMIC_DEBUG_LEVEL */
if( (LMIC.ladrAns & 0x7F) == (MCMD_LADR_ANS_POWACK | MCMD_LADR_ANS_CHACK | MCMD_LADR_ANS_DRACK) ) {
// Nothing went wrong - use settings
LMIC.upRepeat = uprpt;
setDrTxpow(DRCHG_NWKCMD, dr, pow2dBm(p1));
}
LMIC.adrChanged = 1; // Trigger an ACK to NWK
continue;
}
case MCMD_DEVS_REQ: {
LMIC.devsAns = 1;
// LMIC.snr is SNR time 4, convert to real SNR; rounding towards zero.
const int snr = (LMIC.snr + 2) / 4;
// per [1.02] 5.5. the margin is the SNR.
LMIC.devAnsMargin = (u1_t)(0b00111111 & (snr <= -32 ? -32 : snr >= 31 ? 31 : snr));
oidx += 1;
continue;
}
case MCMD_DN2P_SET: {
#if !defined(DISABLE_MCMD_DN2P_SET)
dr_t dr = (dr_t)(opts[oidx+1] & 0x0F);
u1_t rx1DrOffset = (u1_t)((opts[oidx+1] & 0x70) >> 4);
u4_t freq = LMICbandplan_convFreq(&opts[oidx+2]);
LMIC.dn2Ans = 0x80; // answer pending
if( validDR(dr) )
LMIC.dn2Ans |= MCMD_DN2P_ANS_DRACK;
if( freq != 0 )
LMIC.dn2Ans |= MCMD_DN2P_ANS_CHACK;
if (rx1DrOffset <= 3)
LMIC.dn2Ans |= MCMD_DN2P_ANS_RX1DrOffsetAck;
if( LMIC.dn2Ans == (0x80|MCMD_DN2P_ANS_DRACK|MCMD_DN2P_ANS_CHACK| MCMD_DN2P_ANS_RX1DrOffsetAck) ) {
LMIC.dn2Dr = dr;
LMIC.dn2Freq = freq;
LMIC.rx1DrOffset = rx1DrOffset;
DO_DEVDB(LMIC.dn2Dr,dn2Dr);
DO_DEVDB(LMIC.dn2Freq,dn2Freq);
}
#endif // !DISABLE_MCMD_DN2P_SET
oidx += 5;
continue;
}
case MCMD_DCAP_REQ: {
#if !defined(DISABLE_MCMD_DCAP_REQ)
u1_t cap = opts[oidx+1];
// A value cap=0xFF means device is OFF unless enabled again manually.
if( cap==0xFF )
LMIC.opmode |= OP_SHUTDOWN; // stop any sending
LMIC.globalDutyRate = cap & 0xF;
LMIC.globalDutyAvail = os_getTime();
DO_DEVDB(cap,dutyCap);
LMIC.dutyCapAns = 1;
oidx += 2;
#endif // !DISABLE_MCMD_DCAP_REQ
continue;
}
case MCMD_SNCH_REQ: {
#if !defined(DISABLE_MCMD_SNCH_REQ)
u1_t chidx = opts[oidx+1]; // channel
u4_t freq = LMICbandplan_convFreq(&opts[oidx+2]); // freq
u1_t drs = opts[oidx+5]; // datarate span
LMIC.snchAns = 0x80;
if( freq != 0 && LMIC_setupChannel(chidx, freq, DR_RANGE_MAP(drs&0xF,drs>>4), -1) )
LMIC.snchAns |= MCMD_SNCH_ANS_DRACK|MCMD_SNCH_ANS_FQACK;
#endif // !DISABLE_MCMD_SNCH_REQ
oidx += 6;
continue;
}
case MCMD_PING_SET: {
#if !defined(DISABLE_MCMD_PING_SET) && !defined(DISABLE_PING)
u4_t freq = LMICbandplan_convFreq(&opts[oidx+1]);
u1_t flags = 0x80;
if( freq != 0 ) {
flags |= MCMD_PING_ANS_FQACK;
LMIC.ping.freq = freq;
DO_DEVDB(LMIC.ping.intvExp, pingIntvExp);
DO_DEVDB(LMIC.ping.freq, pingFreq);
DO_DEVDB(LMIC.ping.dr, pingDr);
}
LMIC.pingSetAns = flags;
#endif // !DISABLE_MCMD_PING_SET && !DISABLE_PING
oidx += 4;
continue;
}
case MCMD_BCNI_ANS: {
#if !defined(DISABLE_MCMD_BCNI_ANS) && !defined(DISABLE_BEACONS)
// Ignore if tracking already enabled
if( (LMIC.opmode & OP_TRACK) == 0 ) {
LMIC.bcnChnl = opts[oidx+3];
// Enable tracking - bcninfoTries
LMIC.opmode |= OP_TRACK;
// Cleared later in txComplete handling - triggers EV_BEACON_FOUND
ASSERT(LMIC.bcninfoTries!=0);
// Setup RX parameters
LMIC.bcninfo.txtime = (LMIC.rxtime
+ ms2osticks(os_rlsbf2(&opts[oidx+1]) * MCMD_BCNI_TUNIT)
+ ms2osticksCeil(MCMD_BCNI_TUNIT/2)
- BCN_INTV_osticks);
LMIC.bcninfo.flags = 0; // txtime above cannot be used as reference (BCN_PARTIAL|BCN_FULL cleared)
calcBcnRxWindowFromMillis(MCMD_BCNI_TUNIT,1); // error of +/-N ms
EV(lostFrame, INFO, (e_.reason = EV::lostFrame_t::MCMD_BCNI_ANS,
e_.eui = MAIN::CDEV->getEui(),
e_.lostmic = Base::lsbf4(&d[pend]),
e_.info = (LMIC.missedBcns |
(osticks2us(LMIC.bcninfo.txtime + BCN_INTV_osticks
- LMIC.bcnRxtime) << 8)),
e_.time = MAIN::CDEV->ostime2ustime(LMIC.bcninfo.txtime + BCN_INTV_osticks)));
}
#endif // !DISABLE_MCMD_BCNI_ANS && !DISABLE_BEACONS
oidx += 4;
continue;
} /* end case */
case MCMD_TxParamSetupReq: {
#if LMIC_ENABLE_TxParamSetupReq
uint8_t txParam;
txParam = opts[oidx+1];
// we don't allow unrecognized bits to come through
txParam &= (MCMD_TxParam_RxDWELL_MASK|
MCMD_TxParam_TxDWELL_MASK|
MCMD_TxParam_MaxEIRP_MASK);
LMIC.txParam = txParam;
LMIC.txParamSetupAns = 1;
#endif // LMIC_ENABLE_TxParamSetupReq
oidx += 2;
continue;
} /* end case */
case MCMD_DeviceTimeAns: {
#if LMIC_ENABLE_DeviceTimeReq
// don't process a spurious downlink.
if ( LMIC.txDeviceTimeReqState == lmic_RequestTimeState_rx ) {
// remember that it's time to notify the client.
LMIC.txDeviceTimeReqState = lmic_RequestTimeState_success;
// the network time is linked to the time of the last TX.
LMIC.localDeviceTime = LMIC.txend;
// save the network time.
// The first 4 bytes contain the seconds since the GPS epoch
// (i.e January the 6th 1980 at 00:00:00 UTC).
// Note: as per the LoRaWAN specs, the octet order for all
// multi-octet fields is little endian
// Note: the casts are necessary, because opts is an array of
// single byte values, and they might overflow when shifted
LMIC.netDeviceTime = ( (lmic_gpstime_t) opts[oidx + 1] ) |
(((lmic_gpstime_t) opts[oidx + 2]) << 8) |
(((lmic_gpstime_t) opts[oidx + 3]) << 16) |
(((lmic_gpstime_t) opts[oidx + 4]) << 24);
// The 5th byte contains the fractional seconds in 2^-8 second steps
LMIC.netDeviceTimeFrac = opts[oidx + 5];
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": MAC command DeviceTimeAns received: seconds_since_gps_epoch=%"PRIu32", fractional_seconds=%d\n", os_getTime(), LMIC.netDeviceTime, LMIC.netDeviceTimeFrac);
#endif
}
#endif // LMIC_ENABLE_DeviceTimeReq
oidx += 6;
continue;
} /* end case */
} /* end switch */
/* unrecognized mac commands fall out of switch to here */
EV(specCond, ERR, (e_.reason = EV::specCond_t::BAD_MAC_CMD,
e_.eui = MAIN::CDEV->getEui(),
e_.info = Base::lsbf4(&d[pend]),
e_.info2 = Base::msbf4(&opts[oidx])));
/* stop processing options */
break;
} /* end while */
return oidx;
}
static bit_t decodeFrame (void) {
xref2u1_t d = LMIC.frame;
u1_t hdr = d[0];
u1_t ftype = hdr & HDR_FTYPE;
int dlen = LMIC.dataLen;
#if LMIC_DEBUG_LEVEL > 0
const char *window = (LMIC.txrxFlags & TXRX_DNW1) ? "RX1" : ((LMIC.txrxFlags & TXRX_DNW2) ? "RX2" : "Other");
#endif
if( dlen < OFF_DAT_OPTS+4 ||
(hdr & HDR_MAJOR) != HDR_MAJOR_V1 ||
(ftype != HDR_FTYPE_DADN && ftype != HDR_FTYPE_DCDN) ) {
// Basic sanity checks failed
EV(specCond, WARN, (e_.reason = EV::specCond_t::UNEXPECTED_FRAME,
e_.eui = MAIN::CDEV->getEui(),
e_.info = dlen < 4 ? 0 : os_rlsbf4(&d[dlen-4]),
e_.info2 = hdr + (dlen<<8)));
norx:
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": Invalid downlink, window=%s\n", os_getTime(), window);
#endif
LMIC.dataLen = 0;
return 0;
}
// Validate exact frame length
// Note: device address was already read+evaluated in order to arrive here.
int fct = d[OFF_DAT_FCT];
u4_t addr = os_rlsbf4(&d[OFF_DAT_ADDR]);
u4_t seqno = os_rlsbf2(&d[OFF_DAT_SEQNO]);
int olen = fct & FCT_OPTLEN;
int ackup = (fct & FCT_ACK) != 0 ? 1 : 0; // ACK last up frame
int poff = OFF_DAT_OPTS+olen;
int pend = dlen-4; // MIC
if( addr != LMIC.devaddr ) {
EV(specCond, WARN, (e_.reason = EV::specCond_t::ALIEN_ADDRESS,
e_.eui = MAIN::CDEV->getEui(),
e_.info = addr,
e_.info2 = LMIC.devaddr));
goto norx;
}
if( poff > pend ) {
EV(specCond, ERR, (e_.reason = EV::specCond_t::CORRUPTED_FRAME,
e_.eui = MAIN::CDEV->getEui(),
e_.info = 0x1000000 + (poff-pend) + (fct<<8) + (dlen<<16)));
goto norx;
}
int port = -1;
int replayConf = 0;
if( pend > poff )
port = d[poff++];
seqno = LMIC.seqnoDn + (u2_t)(seqno - LMIC.seqnoDn);
if( !aes_verifyMic(LMIC.nwkKey, LMIC.devaddr, seqno, /*dn*/1, d, pend) ) {
EV(spe3Cond, ERR, (e_.reason = EV::spe3Cond_t::CORRUPTED_MIC,
e_.eui1 = MAIN::CDEV->getEui(),
e_.info1 = Base::lsbf4(&d[pend]),
e_.info2 = seqno,
e_.info3 = LMIC.devaddr));
goto norx;
}
if( seqno < LMIC.seqnoDn ) {
if( (s4_t)seqno > (s4_t)LMIC.seqnoDn ) {
EV(specCond, INFO, (e_.reason = EV::specCond_t::DNSEQNO_ROLL_OVER,
e_.eui = MAIN::CDEV->getEui(),
e_.info = LMIC.seqnoDn,
e_.info2 = seqno));
goto norx;
}
if( seqno != LMIC.seqnoDn-1 || !LMIC.dnConf || ftype != HDR_FTYPE_DCDN ) {
EV(specCond, INFO, (e_.reason = EV::specCond_t::DNSEQNO_OBSOLETE,
e_.eui = MAIN::CDEV->getEui(),
e_.info = LMIC.seqnoDn,
e_.info2 = seqno));
goto norx;
}
// Replay of previous sequence number allowed only if
// previous frame and repeated both requested confirmation
replayConf = 1;
}
else {
if( seqno > LMIC.seqnoDn ) {
EV(specCond, INFO, (e_.reason = EV::specCond_t::DNSEQNO_SKIP,
e_.eui = MAIN::CDEV->getEui(),
e_.info = LMIC.seqnoDn,
e_.info2 = seqno));
}
LMIC.seqnoDn = seqno+1; // next number to be expected
DO_DEVDB(LMIC.seqnoDn,seqnoDn);
// DN frame requested confirmation - provide ACK once with next UP frame
LMIC.dnConf = (ftype == HDR_FTYPE_DCDN ? FCT_ACK : 0);
}
if( LMIC.dnConf || (fct & FCT_MORE) )
LMIC.opmode |= OP_POLL;
// We heard from network
LMIC.adrChanged = LMIC.rejoinCnt = 0;
if( LMIC.adrAckReq != LINK_CHECK_OFF )
LMIC.adrAckReq = LINK_CHECK_INIT;
int m = LMIC.rssi - RSSI_OFF - getSensitivity(LMIC.rps);
// for legacy reasons, LMIC.margin is set to the unsigned sensitivity. It can never be negative.
// it's only computed for legacy clients
LMIC.margin = m < 0 ? 0 : m > 254 ? 254 : m;
#if LMIC_DEBUG_LEVEL > 0
// Process OPTS
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": process options (olen=%#x)\n", os_getTime(), olen);
#endif
xref2u1_t opts = &d[OFF_DAT_OPTS];
int oidx = scan_mac_cmds(opts, olen);
if( oidx != olen ) {
EV(specCond, ERR, (e_.reason = EV::specCond_t::CORRUPTED_FRAME,
e_.eui = MAIN::CDEV->getEui(),
e_.info = 0x1000000 + (oidx) + (olen<<8)));
}
if( !replayConf ) {
// Handle payload only if not a replay
// Decrypt payload - if any
if( port >= 0 && pend-poff > 0 ) {
aes_cipher(port <= 0 ? LMIC.nwkKey : LMIC.artKey, LMIC.devaddr, seqno, /*dn*/1, d+poff, pend-poff);
if (port == 0) {
// this is a mac command. scan the options.
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": process mac commands for port 0 (olen=%#x)\n", os_getTime(), pend-poff);
#endif
int optendindex = scan_mac_cmds(d+poff, pend-poff);
if (optendindex != pend-poff) {
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF(
"%"LMIC_PRId_ostime_t": error processing mac commands for port 0 "
"(len=%#x, optendindex=%#x)\n",
os_getTime(), pend-poff, optendindex
);
#endif
}
}
} // end decrypt payload
EV(dfinfo, DEBUG, (e_.deveui = MAIN::CDEV->getEui(),
e_.devaddr = LMIC.devaddr,
e_.seqno = seqno,
e_.flags = (port < 0 ? EV::dfinfo_t::NOPORT : 0) | EV::dfinfo_t::DN,
e_.mic = Base::lsbf4(&d[pend]),
e_.hdr = d[LORA::OFF_DAT_HDR],
e_.fct = d[LORA::OFF_DAT_FCT],
e_.port = port,
e_.plen = dlen,
e_.opts.length = olen,
memcpy(&e_.opts[0], opts, olen)));
} else {
EV(specCond, INFO, (e_.reason = EV::specCond_t::DNSEQNO_REPLAY,
e_.eui = MAIN::CDEV->getEui(),
e_.info = Base::lsbf4(&d[pend]),
e_.info2 = seqno));
}
if( // NWK acks but we don't have a frame pending
(ackup && LMIC.txCnt == 0) ||
// We sent up confirmed and we got a response in DNW1/DNW2
// BUT it did not carry an ACK - this should never happen
// Do not resend and assume frame was not ACKed.
(!ackup && LMIC.txCnt != 0) ) {
EV(specCond, ERR, (e_.reason = EV::specCond_t::SPURIOUS_ACK,
e_.eui = MAIN::CDEV->getEui(),
e_.info = seqno,
e_.info2 = ackup));
#if LMIC_DEBUG_LEVEL > 1
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": ??ack error ack=%d txCnt=%d\n", os_getTime(), ackup, LMIC.txCnt);
#endif
}
if( LMIC.txCnt != 0 ) // we requested an ACK
orTxrxFlags(__func__, ackup ? TXRX_ACK : TXRX_NACK);
if( port <= 0 ) {
orTxrxFlags(__func__, TXRX_NOPORT);
LMIC.dataBeg = poff;
LMIC.dataLen = 0;
} else {
orTxrxFlags(__func__, TXRX_PORT);
LMIC.dataBeg = poff;
LMIC.dataLen = pend-poff;
}
#if LMIC_DEBUG_LEVEL > 0
LMIC_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": Received downlink, window=%s, port=%d, ack=%d, txrxFlags=%#x\n", os_getTime(), window, port, ackup, LMIC.txrxFlags);
#endif
return 1;
}
// ================================================================================
// TX/RX transaction support
static void setupRx2 (void) {
initTxrxFlags(__func__, TXRX_DNW2);
LMIC.rps = dndr2rps(LMIC.dn2Dr);
LMIC.freq = LMIC.dn2Freq;
LMIC.dataLen = 0;
os_radio(RADIO_RX);
}
static void schedRx12 (ostime_t delay, osjobcb_t func, u1_t dr) {
ostime_t hsym = dr2hsym(dr);
LMIC.rxsyms = MINRX_SYMS;
// If a clock error is specified, compensate for it by extending the
// receive window
if (LMIC.clockError != 0) {
// Calculate how much the clock will drift maximally after delay has
// passed. This indicates the amount of time we can be early
// _or_ late.
ostime_t drift = (int64_t)delay * LMIC.clockError / MAX_CLOCK_ERROR;
// Increase the receive window by twice the maximum drift (to
// compensate for a slow or a fast clock).
// decrease the rxtime to compensate for. Note that hsym is a
// *half* symbol time, so the factor 2 is hidden. First check if
// this would overflow (which can happen if the drift is very
// high, or the symbol time is low at high datarates).
if ((255 - LMIC.rxsyms) * hsym < drift)
LMIC.rxsyms = 255;
else
LMIC.rxsyms += drift / hsym;
}
// Center the receive window on the center of the expected preamble
// (again note that hsym is half a sumbol time, so no /2 needed)
LMIC.rxtime = LMIC.txend + delay + PAMBL_SYMS * hsym - LMIC.rxsyms * hsym;
LMIC_X_DEBUG_PRINTF("%"LMIC_PRId_ostime_t": sched Rx12 %"LMIC_PRId_ostime_t"\n", os_getTime(), LMIC.rxtime - RX_RAMPUP);
os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);