IBeacon协议分析
对于一个UUID是E2C56DB5-DFFB-48D2-B060-D0F5A71096E0, major是0, minjor是0的iBeacon，此时的Tx的信号是-59 RSSI，他的BLE的广播包如下：
d6 be 89 8e 40 24 05 a2 17 6e 3d 71 02 01 1a 1a ff 4c 00 02 15 e2 c5 6d b5 df fb 48 d2 b0 60 d0 f5 a7 10 96 e0 00 00 00 00 c5 52 ab 8d 38 a5
以上协议包拆解内容如下:
d6 be 89 8e # Access address for advertising data (this is always the same fixed value) 40 # Advertising Channel PDU Header byte 0. Contains: (type = 0), (tx add = 1), (rx add = 0) 24 # Advertising Channel PDU Header byte 1. Contains: (length = total bytes of the advertising payload + 6 bytes for the BLE mac address.) 05 a2 17 6e 3d 71 # Bluetooth Mac address (note this is a spoofed address) 02 01 1a 1a ff 4c 00 02 15 e2 c5 6d b5 df fb 48 d2 b0 60 d0 f5 a7 10 96 e0 00 00 00 00 c5 # Bluetooth advertisement 52 ab 8d 38 a5 # checksum
协议包中的关键部分就是蓝牙的广播部分，这些被分解为如下：
02 01 1a 1a ff 4c 00 02 15 # Apple's fixed iBeacon advertising prefix e2 c5 6d b5 df fb 48 d2 b0 60 d0 f5 a7 10 96 e0 # iBeacon profile uuid 00 00 # major 00 00 # minor c5 # The 2's complement of the calibrated Tx Power
所有的BLE设备都可以发送以上格式的广播包