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Add payload MAC commands parsing + LinkcheckReq/Ans MAC commands #19

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Add payload MAC commands parsing + LinkcheckReq/Ans MAC commands #19

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1ab33f6
Add `LMIC_setLinkCheckRequestOnce` to send `LinkCheckReq` MAC command
Oliv4945 Jun 25, 2016
20e6d8b
Parse MAC command LinkCheckAns
Oliv4945 Jun 25, 2016
d4b7d68
Parse MAC commands in payload
Oliv4945 Jun 25, 2016
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244 changes: 135 additions & 109 deletions src/lmic/lmic.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1014,119 +1014,16 @@ static int decodeBeacon (void) {
#endif // !DISABLE_BEACONS


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;
const char *window = (LMIC.txrxFlags & TXRX_DNW1) ? "RX1" : ((LMIC.txrxFlags & TXRX_DNW2) ? "RX2" : "Other");
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
printf("%lu: 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;

// Process OPTS
int m = LMIC.rssi - RSSI_OFF - getSensitivity(LMIC.rps);
LMIC.margin = m < 0 ? 0 : m > 254 ? 254 : m;

xref2u1_t opts = &d[OFF_DAT_OPTS];
// Parse MAC commands
static void parseMacCommands (xref2u1_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];
LMIC.gwMargin = opts[oidx+1];
LMIC.nGws = opts[oidx+2];
oidx += 3;
LMIC.lchkReq = 0; // Request only once
continue;
}
case MCMD_LADR_REQ: {
Expand Down Expand Up @@ -1263,12 +1160,126 @@ static bit_t decodeFrame (void) {
e_.eui = MAIN::CDEV->getEui(),
e_.info = 0x1000000 + (oidx) + (olen<<8)));
}
}


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;
const char *window = (LMIC.txrxFlags & TXRX_DNW1) ? "RX1" : ((LMIC.txrxFlags & TXRX_DNW2) ? "RX2" : "Other");
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
printf("%lu: 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;

// Process OPTS
int m = LMIC.rssi - RSSI_OFF - getSensitivity(LMIC.rps);
LMIC.margin = m < 0 ? 0 : m > 254 ? 254 : m;

xref2u1_t opts = &d[OFF_DAT_OPTS];
parseMacCommands(opts, olen);

if( !replayConf ) {
// Handle payload only if not a replay
// Decrypt payload - if any
if( port >= 0 && pend-poff > 0 )
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) { // MAC commands in payload
parseMacCommands(d+poff, pend-poff);
}
}

EV(dfinfo, DEBUG, (e_.deveui = MAIN::CDEV->getEui(),
e_.devaddr = LMIC.devaddr,
Expand Down Expand Up @@ -1628,6 +1639,10 @@ static void buildDataFrame (void) {
LMIC.dn2Ans = 0;
}
#endif // !DISABLE_MCMD_DN2P_SET
if( LMIC.lchkReq ) { // Ask for a link check request (gateway's margin + gateway number)
LMIC.frame[end+0] = MCMD_LCHK_REQ;
end += 1;
}
if( LMIC.devsAns ) { // answer to device status
LMIC.frame[end+0] = MCMD_DEVS_ANS;
LMIC.frame[end+1] = os_getBattLevel();
Expand Down Expand Up @@ -2212,6 +2227,9 @@ void LMIC_reset (void) {
LMIC.dn2Dr = DR_DNW2; // we need this for 2nd DN window of join accept
LMIC.dn2Freq = FREQ_DNW2; // ditto
LMIC.rxDelay = DELAY_DNW1;
LMIC.lchkReq = 0;
LMIC.gwMargin = 0;
LMIC.nGws = 0;
#if !defined(DISABLE_PING)
LMIC.ping.freq = FREQ_PING; // defaults for ping
LMIC.ping.dr = DR_PING; // ditto
Expand Down Expand Up @@ -2339,3 +2357,11 @@ void LMIC_setLinkCheckMode (bit_t enabled) {
void LMIC_setClockError(u2_t error) {
LMIC.clockError = error;
}


// Linkcheckreq
// Ask for a link check request on next frame UP.
// It will ask the network for gateway's margin and the number of gateways
void LMIC_setLinkCheckRequestOnce (bit_t enabled) {
LMIC.lchkReq = 1;
}
5 changes: 5 additions & 0 deletions src/lmic/lmic.h
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Original file line number Diff line number Diff line change
Expand Up @@ -217,6 +217,10 @@ struct lmic_t {
bit_t devsAns; // device status answer pending
u1_t adrEnabled;
u1_t moreData; // NWK has more data pending

bit_t lchkReq; // Send lCheckReq MAC command
u1_t gwMargin; // Gateway margin (lcheckAns)
u1_t nGws; // Number of gateways (lcheckAns)
#if !defined(DISABLE_MCMD_DCAP_REQ)
bit_t dutyCapAns; // have to ACK duty cycle settings
#endif
Expand Down Expand Up @@ -305,6 +309,7 @@ void LMIC_tryRejoin (void);
void LMIC_setSession (u4_t netid, devaddr_t devaddr, xref2u1_t nwkKey, xref2u1_t artKey);
void LMIC_setLinkCheckMode (bit_t enabled);
void LMIC_setClockError(u2_t error);
void LMIC_setLinkCheckRequestOnce (bit_t enabled);

// Declare onEvent() function, to make sure any definition will have the
// C conventions, even when in a C++ file.
Expand Down