mesh: Deliver TTL=1 PDUs only to the local net interface
mesh: Deliver TTL=1 PDUs only to the local net interface

Section 3.4.5.2 in the Mesh Profile Specification (1.0) states:

"The output filter of the interface connected to advertising or GATT
bearers shall drop all messages with TTL value set to 1."

Also: https://www.bluetooth.org/errata/errata_view.cfm?errata_id=9811

Note that this is specifically 1 and not 0, since e.g. Friend PDUs
always go out with TTL 0.

Another noteworthy thing is that the way this has to be implemented is
slightly contrary to how it's presented in the specification (both in
the text as well as the Message processing flow diagram in section
3.11. If this was implemented following the spec to its word, then any
PDU received over GATT or Advertising with TTL 2 would never be
relayed (since the TTL would be 1 when the PDU gets rerouted back to
the bearer). This would be both counterintuitive to the intended
purpose of the TTL, and would also be contrary to the test
specification (see Test Procedure step 1 in MESH/NODE/RLY/BV-01-C).

IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,IMGJulian/incubator-mynewt-core,mlaz/mynewt-core,IMGJulian/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,IMGJulian/incubator-mynewt-core