wtls.c

WTLS安全层源程序

 /*
 * wtls.c - WTLS Server-side implementation
 *
 * Nick Clarey <[e-mail]>
 */

#if (HAVE_WTLS_OPENSSL)

#include "gwlib/gwlib.h"
#include "wtls.h"
#include "timers.h"
#include "wap_events.h"
#include "wtls_pdu.h"
#include "wtls_statesupport.h"
#include "gw/msg.h"

#include "wtp.h"

/***********************************************************************
 * Internal data structures.
 *
 * List of WTLS Server machines.
 */
static List *wtls_machines = NULL;

/*
 * Counter for WTLS Server machine id numbers, to make sure they are unique.
 */
static Counter *wtls_machine_id_counter = NULL;

/*
 * Give the status of wtls server layer:
 *	limbo - not running at all
 *	running - operating normally
 *	terminating - waiting for operations to terminate, returning to limbo
 */
static enum { limbo, running, terminating } wtls_run_status = limbo;

/*
 * Queue of events to be handled by WTLS Server machines.
 */
static List *wtls_queue = NULL;


/*****************************************************************************
 *
 * Prototypes of internal functions:
 */

/*
 * Create and destroy an uninitialized wtls server state machine.
 */

static WTLSMachine* wtls_machine_create(WAPAddrTuple *tuple);
static void wtls_machine_create_destroy(void *sm);
static void wtls_machine_destroy(void * p);

/*
 * Checks whether the list of wlts server machines includes a specific machine.
 *
 * The machine in question is identified with with source and destination
 * address and port. If the machine does not exist and the event is either;
 * - A SEC-Create-Request.req or
 * - A T-Unitdata.ind containing a ClientHello packet or
 * - A T-Unitdata.ind containing an Alert(no_renegotiation) packet
 * a new machine is created and added in the machines data structure. 
 *
 * See WTLS 7.2 for details of this check.
 */
static WTLSMachine *wtls_machine_find_or_create(WAPEvent *event);

/*
 * Feed an event to a WTLS Server state machine. Handle all errors by 
 * itself, do not report them to the caller.
 */
static void wtls_event_handle(WTLSMachine *machine, WAPEvent *event);

/*
 * Print a WTLS Server machine state as a string.
 */
static unsigned char *name_wtlser_state(int name);

/*
 * Find a WTLS Server machine from the global list of wtls server 
 * structures that corresponds to the four-tuple of source and destination 
 * addresses and ports. Return a pointer to the machine, or NULL if not found.
 */
static WTLSMachine *wtls_machine_find(WAPAddrTuple *tuple, long mid);

static void main_thread(void *);
static WTLSMachine *find_wtls_machine_using_mid(long mid);
static void add_wtls_address(Msg *msg, WTLSMachine *wtls_machine);

/* The match* functions are used for searches through lists */
static int match_handshake_type(void* item, void* pattern);
static int match_pdu_type(void* item, void* pattern);

/*static WAPEvent *create_tr_invoke_ind(WTPRespMachine *sm, Octstr *user_data);
static WAPEvent *create_tr_abort_ind(WTPRespMachine *sm, long abort_reason);
static WAPEvent *create_tr_result_cnf(WTPRespMachine *sm); */

/******************************************************************************
 *
 * EXTERNAL FUNCTIONS:
 *
 */
WAPEvent *wtls_unpack_wdp_datagram(Msg *msg)
{
        WAPEvent* unitdataIndEvent;
        List* wtlsPayloadList;

        /* Dump the Msg */
        msg_dump(msg,0);
        
        /* Then, stuff it into a T_Unitdata_Ind Event */
        unitdataIndEvent = wap_event_create(T_Unitdata_Ind);
        info(0,"Event created");
        
        /* Firstly, the address */ 
        unitdataIndEvent->u.T_Unitdata_Ind.addr_tuple =
                wap_addr_tuple_create(msg->wdp_datagram.source_address,
                                      msg->wdp_datagram.source_port,
                                      msg->wdp_datagram.destination_address,
                                      msg->wdp_datagram.destination_port);
        info(0,"Set address and stuff");

        /* Attempt to stuff this baby into a list-of-WTLS-PDUs */
        wtlsPayloadList = wtls_unpack_payloadlist (msg->wdp_datagram.user_data);
        info(0,"Datagram unpacked!");
        
        /* Then, the pdu material */
        unitdataIndEvent->u.T_Unitdata_Ind.pdu_list = wtlsPayloadList;

        /* And return the event */
        return unitdataIndEvent;
}

void wtls_init(void) {
        /* Initialise our various lists and counters */
        wtls_machines = list_create();
        wtls_machine_id_counter = counter_create();
        
        wtls_queue = list_create();
        list_add_producer(wtls_queue);

        /* Idiot check - ensure that we are able to start running */
        gw_assert(wtls_run_status == limbo);
        wtls_run_status = running;
        gwthread_create(main_thread, NULL);
}

void wtls_shutdown(void) {
        /* Make sure that we're actually running; if so, then
           prepare for termination */
        gw_assert(wtls_run_status == running);
        wtls_run_status = terminating;
        list_remove_producer(wtls_queue);
        gwthread_join_every(main_thread);

        /* Print out a friendly message stating that we're going to die */
        debug("wap.wtls", 0, "wtls_shutdown: %ld wtls machines left",
              list_len(wtls_machines));

        /* And clean up nicely after ourselves */
        list_destroy(wtls_machines, wtls_machine_destroy);
        list_destroy(wtls_queue, wap_event_destroy_item);     
        counter_destroy(wtls_machine_id_counter);
}

void wtls_dispatch_event(WAPEvent *event) {
        /* Stick the event on the incoming events queue */
        list_produce(wtls_queue, event);
}

int wtls_get_address_tuple(long mid, WAPAddrTuple **tuple) {
	WTLSMachine *sm;
	
	sm = find_wtls_machine_using_mid(mid);
	if (sm == NULL)
		return -1;

	*tuple = wap_addr_tuple_duplicate(sm->addr_tuple);
	return 0;
}

void send_alert(int alertLevel, int alertDescription, WTLSMachine* wtls_machine) {
        wtls_Payload* alertPayload;
        wtls_PDU* alertPDU;
        
        Octstr* packedAlert;
        Msg* msg = NULL;
        
        alertPDU = (wtls_PDU*) wtls_pdu_create(Alert_PDU);
        alertPDU->u.alert.level = alertLevel;
        alertPDU->u.alert.desc = alertDescription;

        /* Here's where we should get the current checksum from the wtls_machine */
        alertPDU->u.alert.chksum = 0;

        /* Pack the PDU */
        msg = msg_create(wdp_datagram);
        add_wtls_address(msg, wtls_machine);

        /* Pack the message */
        alertPayload = wtls_pdu_pack(alertPDU, wtls_machine);

        packedAlert = (Octstr*) wtls_payload_pack(alertPayload);
        msg->wdp_datagram.user_data = packedAlert;

        /* And destroy the structure */
        wtls_payload_destroy(alertPayload);
        alertPayload = NULL;
        
        /* Send it off */
        write_to_bearerbox(msg);
}

void clear_queuedpdus(WTLSMachine* wtls_machine)
{
}

void add_pdu(WTLSMachine* wtls_machine, wtls_PDU* pduToAdd)
{
        int currentLength;
        wtls_Payload* payloadToAdd;
        Octstr* packedPDU;

        /* Check to see if we've already allocated some memory for the list */
        if (wtls_machine->packet_to_send == NULL) {
                wtls_machine->packet_to_send = octstr_create("");
        }

        /* Pack and encrypt the pdu */
        payloadToAdd = wtls_pdu_pack(pduToAdd, wtls_machine);

        /* If the pdu is a Handshake pdu, append the Octstr to our wtls_machine's
           exchanged_handshakes Octstr */
        packedPDU = wtls_payload_pack(payloadToAdd);

        /* Add it to our list */
        currentLength = octstr_len(wtls_machine->packet_to_send);
        octstr_insert(wtls_machine->packet_to_send, packedPDU, currentLength);
}


/*
 * Send the pdu_to_send list to the destination specified by the address in the machine
 * structure. Don't return anything, handle all errors internally.
 */
void send_queuedpdus(WTLSMachine* wtls_machine)
{
        Msg* msg = NULL;

        gw_assert(wtls_machine->packet_to_send != NULL);
        
        /* Pack the PDU */
        msg = msg_create(wdp_datagram);
        add_wtls_address(msg, wtls_machine);
        msg->wdp_datagram.user_data = octstr_duplicate(wtls_machine->packet_to_send);

        /* Send it off */
        write_to_bearerbox(msg);

        /* Destroy our copy of the sent string */
        octstr_destroy(wtls_machine->packet_to_send);
        wtls_machine->packet_to_send = NULL;
        
}


/* 
 * Add address from  state machine.
 */
void add_wtls_address(Msg *msg, WTLSMachine *wtls_machine){

       debug("wap.wtls", 0, "adding address");
       msg->wdp_datagram.source_address = 
    	    octstr_duplicate(wtls_machine->addr_tuple->local->address);
       msg->wdp_datagram.source_port = wtls_machine->addr_tuple->local->port;
       msg->wdp_datagram.destination_address = 
    	    octstr_duplicate(wtls_machine->addr_tuple->remote->address);
       msg->wdp_datagram.destination_port = 
            wtls_machine->addr_tuple->remote->port;
}

/*****************************************************************************
 *
 * INTERNAL FUNCTIONS:
 *
 */

static void main_thread(void *arg) {
	WTLSMachine *sm;
	WAPEvent *e;
        
	while (wtls_run_status == running && 
               (e = list_consume(wtls_queue)) != NULL) {
		sm = wtls_machine_find_or_create(e);
		if (sm == NULL)
			wap_event_destroy(e);
		else
			wtls_event_handle(sm, e);
                }
}

/*
 * Give the name of a WTLS Server state in a readable form. 
 */
static unsigned char *name_wtls_state(int s){
       switch (s){
              #define STATE_NAME(state) case state: return #state;
              #define ROW(state, event, condition, action, new_state)
              #include "wtls_state-decl.h"
              default: