Security: Re-enable auth-failure (try w/o security); Resolve L2CAPComm::open() BT_SECURITY deadlock

Re-enable auth-failure (try w/o security) from hciSMPMsgCallback()

Resolve L2CAPComm::open() BT_SECURITY deadlock
- set sec_level after connect() within L2CAPComm::open()

- see macro SET_BT_SECURITY_POST_CONNECT in L2CAPComm.cpp

- L2CAPComm::setBTSecurityLevel() ignores unchanged BT_SECURITY value.
  Otherwise it fails on BTSecurityLevel::NONE, don't ask - don't know, even after BlueZ/Kernel review.

Working w/ DBTScanner10:
- Device w/o security: No special settings in commandline
- Device w/ Secure Connection SMP: Only set passkey in commandline
- Device w/ legacy encryption only (no auth): Set BTSecurityLevel::ENC_ONLY or SMPIOCapabilities::NO_INPUT_NO_OUTPUT or both.

1 files changed, 3 insertions, 4 deletions

diff --git a/api/direct_bt/L2CAPComm.hpp b/api/direct_bt/L2CAPComm.hpp
index 9ff2f069..21719d7f 100644
--- a/api/direct_bt/L2CAPComm.hpp
+++ b/api/direct_bt/L2CAPComm.hpp
@@ -143,7 +143,7 @@ namespace direct_bt {
             std::atomic<pthread_t> tid_read;
 
             bool setBTSecurityLevelImpl(const BTSecurityLevel sec_level);
-            bool getBTSecurityLevelImpl(BTSecurityLevel& sec_level);
+            BTSecurityLevel getBTSecurityLevelImpl();
 
         public:
             /**
@@ -197,10 +197,9 @@ namespace direct_bt {
             /**
              * Fetches the current BlueZ's L2CAP socket BT_SECURITY sec_level.
              *
-             * @param sec_level return value reference written to if method returns true
-             * @return true if successful with result written to sec_level, otherwise false.
+             * @return BTSecurityLevel  sec_level value, BTSecurityLevel::UNSET if failure
              */
-            bool getBTSecurityLevel(BTSecurityLevel& sec_level);
+            BTSecurityLevel getBTSecurityLevel();
 
             /** Generic read, w/o locking suitable for a unique ringbuffer sink. Using L2CAPEnv::L2CAP_READER_POLL_TIMEOUT.*/
             jau::snsize_t read(uint8_t* buffer, const jau::nsize_t capacity);