The (BT)SAP (Bluetooth SIM Access Profile) is a part of Bluetooth
specifications, that defines the protocol and procedures that
shall be used to access a smart card (usually GSM SIM) via
a Bluetooth link.
The profile defines two roles:
- Server - the side that has direct access to a smart card.
It acts as a SIM card reader, which assists the Client
in accessing and controlling the smart card.
- Client - the side that accesses and controls the smart card
inside the Server through the connection with Server.
Typical examples of a Server are a simple SIM card holder or
a portable phone in the car environment. A typical example of
a Client is a car phone, which uses a subscription module in
the Server for a connection to the cellular network.
OsmocomBB implements the Client role providing abstract SAP
interface API to the higher layers. Instead of Bluetooth,
a UNIX socket is used to communicate with a Server.
The previous implementation of (BT)SAP interface was incomplete
and hard to maintain. This change (re)implements it almost from
scratch on top of the Osmocom FSM framework.
Besides that, the most significant changes are:
- The implementation is separated into three parts:
- sap_interface.{c|h} - public SAP interface API,
- sap_proto.{c|h} - SAP protocol definition,
- sap_fsm.{c|h} - SAP FSM implementation.
- Both 'sap_message' and 'sap_param' structures follow the
SAP message format definition according to 5.1 and 5.2.
- The message parsing is done more carefully in order to
prevent buffer overflow and NULL-pointer dereference.
- Introduced public API for getting / adding message
parameters, and checking the ResultCode.
- Introduced public API for opening / closing a connection
with the server, powering on / off and resetting the SIM
card, sending ATR and APDU.
- Introduced a call-back for handling the response message.
- Card reader state is also a part of the public API.
The new implementation was tested against softsim [1]. The
only limitation is Server-initiated Release, that allows the
Server to 'ask' a Client to release connection as soon as
communication with the smart card is finished. This is not
implemented (yet), and leads to immediate release.
[1] https://git.osmocom.org/softsim/
Change-Id: I77bb108615bb2c94c441568f195b04e0a5421643
When starting multiple mobile in the same second, the libc random number
generator will be seeded to exactly the same value.
The random bits inside the RACH request(s) will be exactly the same
across multiple mobile and when the channel fails they all pick the same
randomized back-off timing.
Use stronger random numbers and replace all calls to random(2) with
osmo_get_rand_id. Add a fallback to try random().
[v2: Add helper to make sure the result is int and between 0 and
RAND_MAX]
Change-Id: Icdd4be88c62bba1e9d954568e48f0c12a67ac182
Since libosmocore already has LAPDm implementation, we don't need the
local copy of LAPDm code anymore.
Written-by: Andreas Eversberg <jolly@eversberg.eu>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
This split the headers and adapt the source.
We use osmocom/bb as a prefix because libosomore also
uses osmocom and generic names such as misc & common could
conflict in the future.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Harald Welte
Vadim Yanitskiy
Sylvain Munaut