diff options
| -rw-r--r-- | src/target/fake_trx/burst_fwd.py | 90 |
1 files changed, 61 insertions, 29 deletions
diff --git a/src/target/fake_trx/burst_fwd.py b/src/target/fake_trx/burst_fwd.py index bcf2257e..503d035f 100644 --- a/src/target/fake_trx/burst_fwd.py +++ b/src/target/fake_trx/burst_fwd.py @@ -39,42 +39,75 @@ class BurstForwarder: # one GSM symbol advance. ta = 0 - # Constants - # TODO: add options to change this - RSSI_RAND_TRESHOLD = 10 - RSSI_RAND_MIN = -90 - RSSI_RAND_MAX = -60 + # Timing of Arrival values indicated by transceiver + # in units of 1/256 of GSM symbol periods. A pair of + # base and threshold values defines a range of ToA value + # randomization: from (base - threshold) to (base + threshold). + toa256_dl_base = 0 + toa256_ul_base = 0 - # TODO: add options to change this - TOA256_RAND_TRESHOLD = 128 - TOA256_RAND_BASE = 0 + toa256_dl_threshold = 128 + toa256_ul_threshold = 128 + + # RSSI values indicated by transceiver in dBm. + # A pair of base and threshold values defines a range of RSSI + # randomization: from (base - threshold) to (base + threshold). + rssi_dl_base = -60 + rssi_ul_base = -70 + + rssi_dl_threshold = 10 + rssi_ul_threshold = 5 def __init__(self, bts_link, bb_link): self.bts_link = bts_link self.bb_link = bb_link - # Generate a random RSSI range - rssi = random.randint(self.RSSI_RAND_MIN, self.RSSI_RAND_MAX) - self.rssi_min = rssi - self.RSSI_RAND_TRESHOLD - self.rssi_max = rssi + self.RSSI_RAND_TRESHOLD + # Calculates a random ToA value for Downlink bursts + def calc_dl_toa256(self): + # Calculate a range for randomization + toa256_min = self.toa256_dl_base - self.toa256_dl_threshold + toa256_max = self.toa256_dl_base + self.toa256_dl_threshold + + # Generate a random ToA value + toa256 = random.randint(toa256_min, toa256_max) + + return toa256 - # Generate a random ToA range - self.toa256_min = self.TOA256_RAND_BASE - self.TOA256_RAND_TRESHOLD - self.toa256_max = self.TOA256_RAND_BASE + self.TOA256_RAND_TRESHOLD + # Calculates a random ToA value for Uplink bursts + def calc_ul_toa256(self): + # Calculate a range for randomization + toa256_min = self.toa256_ul_base - self.toa256_ul_threshold + toa256_max = self.toa256_ul_base + self.toa256_ul_threshold - # Calculates ToA value for Uplink bursts (coming to a BTS) - def calc_toa_ul(self): # Generate a random ToA value - toa256 = random.randint(self.toa256_min, self.toa256_max) + toa256 = random.randint(toa256_min, toa256_max) - # Apply TA value + # Apply TA value indicated by MS ta256 = self.ta * 256 toa256 -= ta256 return toa256 + # Calculates a random RSSI value for Downlink bursts + def calc_dl_rssi(self): + # Calculate a range for randomization + rssi_min = self.rssi_dl_base - self.rssi_dl_threshold + rssi_max = self.rssi_dl_base + self.rssi_dl_threshold + + # Generate a random RSSI value + return random.randint(rssi_min, rssi_max) + + # Calculates a random RSSI value for Uplink bursts + def calc_ul_rssi(self): + # Calculate a range for randomization + rssi_min = self.rssi_ul_base - self.rssi_ul_threshold + rssi_max = self.rssi_ul_base + self.rssi_ul_threshold + + # Generate a random RSSI value + return random.randint(rssi_min, rssi_max) + # Converts a L12TRX message to TRX2L1 message - def transform_msg(self, msg_raw): + def transform_msg(self, msg_raw, dl = True): # Attempt to parse a message try: msg_l12trx = DATAMSG_L12TRX() @@ -87,10 +120,12 @@ class BurstForwarder: msg_trx2l1 = msg_l12trx.gen_trx2l1() # Randomize both RSSI and ToA values - msg_trx2l1.rssi = msg_trx2l1.rand_rssi( - min = self.rssi_min, max = self.rssi_max) - msg_trx2l1.toa256 = msg_trx2l1.rand_toa256( - min = self.toa256_min, max = self.toa256_max) + if dl: + msg_trx2l1.toa256 = self.calc_dl_toa256() + msg_trx2l1.rssi = self.calc_dl_rssi() + else: + msg_trx2l1.toa256 = self.calc_ul_toa256() + msg_trx2l1.rssi = self.calc_ul_rssi() return msg_trx2l1 @@ -108,7 +143,7 @@ class BurstForwarder: return None # Process a message - msg = self.transform_msg(data) + msg = self.transform_msg(data, dl = True) if msg is None: return None @@ -140,13 +175,10 @@ class BurstForwarder: return None # Process a message - msg = self.transform_msg(data) + msg = self.transform_msg(data, dl = False) if msg is None: return None - # Emulate ToA value for BTS - msg.toa256 = self.calc_toa_ul() - # Validate and generate the payload payload = msg.gen_msg() |