osmo-remsim/doc/manuals/chapters/rspro.adoc

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[[rspro]]
== RSPRO
*RSPRO*, the *Remote SIM Protocol*, is an osmo-remsim specific,
non-standard communications protocol used between the elements of the
osmo-remsim system.
It is specified in ASN.1 syntax (see `asn1/RSPRO.asn` in the
`osmo-remsim` source code) and uses BER (Basic Encoding Rules) on the
transport level.
WARNING: RSPRO and its underlying transport layer both operate in plain-text,
There is no authentication or encryption built into the protocol. It is
assumed that the protocol is only spoken over trusted, controlled IP
networks, such as inside a VPN or a closed / private corporate network.
=== Underlying Transport Layer
RSPRO uses TCP as an underlying transport protocol. As TCP doesn't
preserve message boundaries, the IPA multiplex is used as intermediate
layer between TCP and the BER-encoded RSPRO PDU.
For more information about the IPA multiplex, see the related chapter
in http://ftp.osmocom.org/docs/latest/osmobts-abis.pdf
RSPRO uses the IPA CCM PING/PONG messages for keep-alive and detection
of dead/stale connections. The compiled-in defaults transmits one IPA
PING every 30s and waits 10s for a response from the peer before
declaring the connection as dead.
=== RSPRO PDU
An RsproPDU consists of:
* *version* of the protocol (v2 is current)
* *tag* specified by the sender, echoed back by the receiver in
its response so the server can map responses back to a specific
request
* *msg* the actual RSPRO Message (union/choice)
=== RSPRO Operations
Each RSPRO Operation typically (unless specified othewise) consists of a
Request and Response pair.
==== ConnectBank
This is used by `remsim-bankd` to identify itself to `remsim-server` and
to establish a logical connection between the two elements.
==== ConnectClient
This is used by `remsim-client` to identify itself to `remsim-server`
and to establish a logical connection between the two elements.
==== CreateMapping
This is used by `remsim-server` to install a slot mapping in a
`remsim-bankd`.
==== RemoveMapping
This is used by `remsim-server` to remove a slot mapping from a
`remsim-bankd`.
==== ConfigClientId
This is used by `remsim-server` to dynamically configure a ClientID in a
`remsim-client`. This mode is currently not supported yet, each client
must have a locally-configured ClientID.
==== ConfigClientBank
This is used by `remsim-server` to inform a `remsim-client` about the
details (bankd ID, slot number, IP address, TCP port) of a the
`remsim-bankd` to which it shall connect.
==== ErrorInd
This is a generic error indication that can be sent by any RSRPO entity.
==== SetAtr
This is used by `remsim-bankd` to inform the `remsim-client` about the
ATR of the card, so that `remsim-client` can replicate that ATR when
answering to the reset of the SIM card interface of the phone/modem.
==== TpduModemToCard
This is used by `remsim-client` to transfer a command TPDU/APDU from the
phone/modem to the SIM card in `remsim-bankd`
==== TpduCardToModem
This is used by `remsim-bankd` to transfer a response TPDU/APDU from the
SIM card back to the phone/modem at `remsim-client`.
==== ClientSlotStatusInd
This is used by `remsim-client` to report the status of a given slot.
==== BankSlotStatusInd
This is used by `remsim-bankd` to report the status of a given slot.