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Transceiver: Clean up receival of downlink bursts 

Use a packed structure to clearly indicate what is contained in the
received buffer.

Change-Id: I4d8c0e3c0c717699889f79e50c778d14b6058f2d
This commit is contained in:
Pau Espin 2019-08-26 11:21:55 +02:00
parent e7195ac7d0
commit e4166be76f
2 changed files with 31 additions and 25 deletions
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49
Transceiver52M/Transceiver.cpp
View File

@ -929,8 +929,8 @@ bool Transceiver::driveTxPriorityQueue(size_t chan)
{
int msgLen;
int burstLen;
char buffer[EDGE_BURST_NBITS + 50];
struct trxd_hdr_common *chdr;
struct trxd_hdr_v01_dl *dl;
char buffer[sizeof(*dl) + EDGE_BURST_NBITS];
uint32_t fn;
// check data socket
@ -940,54 +940,53 @@ bool Transceiver::driveTxPriorityQueue(size_t chan)
return false;
}
if (msgLen == gSlotLen + 1 + 4 + 1) {
burstLen = gSlotLen;
} else if (msgLen == EDGE_BURST_NBITS + 1 + 4 + 1) {
if (mSPSTx != 4)
switch (msgLen) {
case sizeof(*dl) + gSlotLen: /* GSM burst */
burstLen = gSlotLen;
break;
case sizeof(*dl) + EDGE_BURST_NBITS: /* EDGE burst */
if (mSPSTx != 4) {
LOG(ERR) << "EDGE burst received but SPS is set to " << mSPSTx;
return false;
}
burstLen = EDGE_BURST_NBITS;
break;
default:
LOG(ERR) << "badly formatted packet on GSM->TRX interface (len="<< msgLen << ")";
return false;
burstLen = EDGE_BURST_NBITS;
} else {
LOG(ERR) << "badly formatted packet on GSM->TRX interface";
return false;
}
/* Common header part: HDR version, TDMA TN & FN */
chdr = (struct trxd_hdr_common *) buffer;
dl = (struct trxd_hdr_v01_dl *) buffer;
/* Convert TDMA FN to the host endianness */
fn = osmo_load32be(&chdr->fn);
fn = osmo_load32be(&dl->common.fn);
/* Make sure we support the received header format */
switch (chdr->version) {
switch (dl->common.version) {
case 0:
/* Version 1 has the same format */
case 1:
break;
default:
LOG(ERR) << "Rx TRXD message with unknown header version " << chdr->version;
LOG(ERR) << "Rx TRXD message with unknown header version " << dl->common.version;
return false;
}
LOG(DEBUG) << "Rx TRXD message (hdr_ver=" << chdr->version << "): "
<< "fn=" << fn << ", tn=" << chdr->tn << ", "
LOG(DEBUG) << "Rx TRXD message (hdr_ver=" << dl->common.version << "): "
<< "fn=" << fn << ", tn=" << dl->common.tn << ", "
<< "burst_len=" << burstLen;
int RSSI = (int) buffer[5];
BitVector newBurst(burstLen);
BitVector::iterator itr = newBurst.begin();
char *bufferItr = buffer+6;
uint8_t *bufferItr = dl->soft_bits;
while (itr < newBurst.end())
*itr++ = *bufferItr++;
GSM::Time currTime = GSM::Time(fn, chdr->tn);
GSM::Time currTime = GSM::Time(fn, dl->common.tn);
addRadioVector(chan, newBurst, RSSI, currTime);
addRadioVector(chan, newBurst, dl->tx_att, currTime);
return true;
}
void Transceiver::driveReceiveRadio()

7
Transceiver52M/proto_trxd.h
View File

@ -66,6 +66,13 @@ struct trxd_hdr_v0 {
uint8_t soft_bits[0];
} __attribute__ ((packed));
/* Downlink burst (BTS->TRX), v0 anf v1 use same format */
struct trxd_hdr_v01_dl {
struct trxd_hdr_common common;
uint8_t tx_att; /* Tx Attentuation */
uint8_t soft_bits[0];
} __attribute__ ((packed));
#define TRXD_MODULATION_GMSK(ts_set) (0b0000 | (ts_set & 0b0011))
#define TRXD_MODULATION_8PSK(ts_set) (0b0100 | (ts_set & 0b0001))