dectmon deciphering

[Patrick McHardy]

Just in case someone is interested - I've just pushed out changes
to allow dectmon to decipher connections if it was able to track
the initial key allocation (and thus knows the UAK). The PIN it
uses is currently hardcoded to "0000" in src/nwk.c, so make sure
to change it to use your own PIN or add brute forcing :)

If someone wants to play with this, I'm still looking for traces
of Siemens phones during pairing, location updates etc :)

...
NWK: 05 40 0a 03 01 18 18 0c 08 23 b1 0e 03 7d 0d 3f
|. at .......#...}.?|
NWK: ee 0e 08 77 1c 1c 5f aa a6 06 33
|...w.._...3|
{MM-AUTHENTICATION-REQUEST} message:
  IE: <<AUTH-TYPE>> id: a len: 5 dst: 0x60c2e0
	authentication algorithm: DSAA (1)
	authentication key type: User authentication key (1)
	authentication key number: 8
	cipher key number: 8
	INC: 0 DEF: 0 TXC: 0 UPC: 1
  IE: <<RAND>> id: c len: 10 dst: 0x60c4c0
	value: ee3f0d7d030eb123
  IE: <<RS>> id: e len: 10 dst: 0x60c4e0
	value: 3306a6aa5f1c1c77

NWK: 85 41 0d 04 ba 5b b8 af
|.A...[..|
{MM-AUTHENTICATION-REPLY} message:
  IE: <<RES>> id: d len: 6 dst: 0x60c660
	value: afb85bba

authentication successful
DCK: 30 e5 60 b3 b9 f6 ee e8
|0.`.....|

NWK: 05 4c 19 02 81 98
|.L....|
{MM-CIPHER-REQUEST} message:
  IE: <<CIPHER-INFO>> id: 19 len: 4 dst: 0x60c2b0
	enable: 1
	cipher algorithm: DECT Standard Cipher 1 (1)
	cipher key type: derived (9)
	cipher key num: 8

ciphering enabled: FP->PP
ciphering enabled: PP->FP

NWK: 83 0d 1e 02 80 88 7c 04 90 02 00 84
|......|.....|
{CC-SETUP-ACK} message:
  IE: <<PROGRESS-INDICATOR>> id: 1e len: 4 dst: 0x60c660
	Location: user (0)
	Progress description: In-band information or appropriate pattern now
available (8)
  IE: <<CODEC-LIST>> id: 7c len: 6 dst: 0x60c940
	Negotiation Indicator: codec negotiation (1)
	Codec 1:
	 Codec: G.726 (32kbit) (2)
	 MAC/DLC Service: DLC service: LU1, MAC service: I_NA (0)
	 Slot size: full slot (4)
	 C-Plane routing: C_S only (0)