• Johan Hedberg's avatar
    Bluetooth: Increase SMP re-encryption delay to 500ms · 5ed884d7
    Johan Hedberg authored
    In some cases the current 250ms delay is not enough for the remote to
    receive the keys, as can be witnessed by the following log:
    
    > ACL Data RX: Handle 64 flags 0x02 dlen 21               [hci1] 231.414217
          SMP: Signing Information (0x0a) len 16
            Signature key: 555bb66b7ab3abc9d5c287c97fe6eb29
    < ACL Data TX: Handle 64 flags 0x00 dlen 21               [hci1] 231.414414
          SMP: Encryption Information (0x06) len 16
            Long term key: 2a7cdc233c9a4b1f3ed31dd9843fea29
    < ACL Data TX: Handle 64 flags 0x00 dlen 15               [hci1] 231.414466
          SMP: Master Identification (0x07) len 10
            EDIV: 0xeccc
            Rand: 0x322e0ef50bd9308a
    < ACL Data TX: Handle 64 flags 0x00 dlen 21               [hci1] 231.414505
          SMP: Signing Information (0x0a) len 16
            Signature key: bbda1b2076e2325aa66fbcdd5388f745
    > HCI Event: Number of Completed Packets (0x13) plen 5    [hci1] 231.483130
            Num handles: 1
            Handle: 64
            Count: 2
    < HCI Command: LE Start Encryption (0x08|0x0019) plen 28  [hci1] 231.664211
            Handle: 64
            Random number: 0x5052ad2b75fed54b
            Encrypted diversifier: 0xb7c2
            Long term key: a336ede66711b49a84bde9b41426692e
    > HCI Event: Command Status (0x0f) plen 4                 [hci1] 231.666937
          LE Start Encryption (0x08|0x0019) ncmd 1
            Status: Success (0x00)
    > HCI Event: Number of Completed Packets (0x13) plen 5    [hci1] 231.712646
            Num handles: 1
            Handle: 64
            Count: 1
    > HCI Event: Disconnect Complete (0x05) plen 4            [hci1] 232.562587
            Status: Success (0x00)
            Handle: 64
            Reason: Remote User Terminated Connection (0x13)
    
    As can be seen, the last key (Signing Information) is sent at 231.414505
    but the completed packets event for it comes only at 231.712646,
    i.e. roughly 298ms later.
    
    To have a better margin of error this patch increases the delay to
    500ms.
    Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
    Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
    5ed884d7
smp.h 4.37 KB