Nfcd

nfcd is a daemon running under the mobile user. It handles the communications between PassKit and the underlying hardware and libraries.

The core objects in it are:

• NFDaemon
• NFFieldDetectController
• NFCoreTelephonyConnection
• NFPowerManager
• NFAbstractController
• NFCardEmulationController
• NFSecureElementController

NFDaemon - (void)XPCConnection:(id) didReceiveCommand:(id)

Launchd plist

{
    EnablePressuredExit = 1;
    EnableTransactions = 1;
    ExitTimeOut = 45;
    Label = "com.apple.nfcd";
    MachServices =     {
        "com.apple.nfcd" = 1;
    };
    ProcessType = Interactive;
    Program = "/usr/libexec/nfcd";
    UserName = mobile;
}

Where the XPC service is registered under the "com.apple.nfcd" name

Supported XPC Commands

ID	Command
1	q_registerConnection:info:
2	q_unregisterConnection:
3-64	send command to SE controller
65	q_updateSecureElementPowerState
66	_seIsInRestrictedMode
67	restrictedModeChanged
68-239	callSEContoller
240	setDeviceString
241	q_getControllerInfo
242	q_getSecureElementInfo
243	q_getBoosterInfo
244	q_readBoosterRegister
245	q_sendBoosterCommand
246	q_triggerAssertion
>247	throw error

A command is send by using the key "command" which is set to the corresponding uint64_t value above. i.e

xpc_dictionary_set_uint64(xpc_dictionary, "command", <command here>")

see https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/xpc_dictionary_set_uint64.3.html

NFDaemon - (unsigned int)q_unregisterConnection:(XPCConnection)

This functions checks for an existing controller for the

• [NFCardEmulationController embeddedCardEmulationController]
• [NFCardEmulationController UICCCardEmulationController]
• [NFSecureElementController seController]
• [NFFieldDetectController fieldDetectController]

Then when it finds the appropriate controller then calls the unregister function for it.