/* 
 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#define THIS_FILE   "stateless_proxy.c"

/* Common proxy functions */
#define STATEFUL    0
#include "proxy.h"


/* Callback to be called to handle incoming requests. */
static pj_bool_t on_rx_request( pjsip_rx_data *rdata );

/* Callback to be called to handle incoming response. */
static pj_bool_t on_rx_response( pjsip_rx_data *rdata );


static pj_status_t init_stateless_proxy(void)
{
    static pjsip_module mod_stateless_proxy =
    {
        NULL, NULL,                         /* prev, next.      */
        { "mod-stateless-proxy", 19 },      /* Name.            */
        -1,                                 /* Id               */
        PJSIP_MOD_PRIORITY_UA_PROXY_LAYER,  /* Priority         */
        NULL,                               /* load()           */
        NULL,                               /* start()          */
        NULL,                               /* stop()           */
        NULL,                               /* unload()         */
        &on_rx_request,                     /* on_rx_request()  */
        &on_rx_response,                    /* on_rx_response() */
        NULL,                               /* on_tx_request.   */
        NULL,                               /* on_tx_response() */
        NULL,                               /* on_tsx_state()   */
    };

    pj_status_t status;

    /* Register our module to receive incoming requests. */
    status = pjsip_endpt_register_module( global.endpt, &mod_stateless_proxy);
    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);

    return PJ_SUCCESS;
}


/* Callback to be called to handle incoming requests. */
static pj_bool_t on_rx_request( pjsip_rx_data *rdata )
{
    pjsip_tx_data *tdata;
    pj_status_t status;


    /* Verify incoming request */
    status = proxy_verify_request(rdata);
    if (status != PJ_SUCCESS) {
        app_perror("RX invalid request", status);
        return PJ_TRUE;
    }

    /*
     * Request looks sane, next clone the request to create transmit data.
     */
    status = pjsip_endpt_create_request_fwd(global.endpt, rdata, NULL,
                                            NULL, 0, &tdata);
    if (status != PJ_SUCCESS) {
        pjsip_endpt_respond_stateless(global.endpt, rdata,
                                      PJSIP_SC_INTERNAL_SERVER_ERROR, NULL, 
                                      NULL, NULL);
        return PJ_TRUE;
    }


    /* Process routing */
    status = proxy_process_routing(tdata);
    if (status != PJ_SUCCESS) {
        app_perror("Error processing route", status);
        return PJ_TRUE;
    }

    /* Calculate target */
    status = proxy_calculate_target(rdata, tdata);
    if (status != PJ_SUCCESS) {
        app_perror("Error calculating target", status);
        return PJ_TRUE;
    }

    /* Target is set, forward the request */
    status = pjsip_endpt_send_request_stateless(global.endpt, tdata, 
                                                NULL, NULL);
    if (status != PJ_SUCCESS) {
        app_perror("Error forwarding request", status);
        return PJ_TRUE;
    }

    return PJ_TRUE;
}


/* Callback to be called to handle incoming response. */
static pj_bool_t on_rx_response( pjsip_rx_data *rdata )
{
    pjsip_tx_data *tdata;
    pjsip_response_addr res_addr;
    pjsip_via_hdr *hvia;
    pj_status_t status;

    /* Create response to be forwarded upstream (Via will be stripped here) */
    status = pjsip_endpt_create_response_fwd(global.endpt, rdata, 0, &tdata);
    if (status != PJ_SUCCESS) {
        app_perror("Error creating response", status);
        return PJ_TRUE;
    }

    /* Get topmost Via header */
    hvia = (pjsip_via_hdr*) pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL);
    if (hvia == NULL) {
        /* Invalid response! Just drop it */
        pjsip_tx_data_dec_ref(tdata);
        return PJ_TRUE;
    }

    /* Calculate the address to forward the response */
    pj_bzero(&res_addr, sizeof(res_addr));
    res_addr.dst_host.type = PJSIP_TRANSPORT_UDP;
    res_addr.dst_host.flag = pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);

    /* Destination address is Via's received param */
    res_addr.dst_host.addr.host = hvia->recvd_param;
    if (res_addr.dst_host.addr.host.slen == 0) {
        /* Someone has messed up our Via header! */
        res_addr.dst_host.addr.host = hvia->sent_by.host;
    }

    /* Destination port is the rpot */
    if (hvia->rport_param != 0 && hvia->rport_param != -1)
        res_addr.dst_host.addr.port = hvia->rport_param;

    if (res_addr.dst_host.addr.port == 0) {
        /* Ugh, original sender didn't put rport!
         * At best, can only send the response to the port in Via.
         */
        res_addr.dst_host.addr.port = hvia->sent_by.port;
    }

    /* Forward response */
    status = pjsip_endpt_send_response(global.endpt, &res_addr, tdata, 
                                       NULL, NULL);
    if (status != PJ_SUCCESS) {
        pjsip_tx_data_dec_ref(tdata);
        app_perror("Error forwarding response", status);
        return PJ_TRUE;
    }

    return PJ_TRUE;
}


/*
 * main()
 */
int main(int argc, char *argv[])
{
    pj_status_t status;

    global.port = 5060;
    pj_log_set_level(4);

    status = init_options(argc, argv);
    if (status != PJ_SUCCESS)
        return 1;

    status = init_stack();
    if (status != PJ_SUCCESS) {
        app_perror("Error initializing stack", status);
        return 1;
    }

    status = init_proxy();
    if (status != PJ_SUCCESS) {
        app_perror("Error initializing proxy", status);
        return 1;
    }

    status = init_stateless_proxy();
    if (status != PJ_SUCCESS) {
        app_perror("Error initializing stateless proxy", status);
        return 1;
    }

#if PJ_HAS_THREADS
    status = pj_thread_create(global.pool, "sproxy", &worker_thread, 
                              NULL, 0, 0, &global.thread);
    if (status != PJ_SUCCESS) {
        app_perror("Error creating thread", status);
        return 1;
    }

    while (!global.quit_flag) {
        char line[10];

        puts("\n"
             "Menu:\n"
             "  q    quit\n"
             "  d    dump status\n"
             "  dd   dump detailed status\n"
             "");

        if (fgets(line, sizeof(line), stdin) == NULL) {
            puts("EOF while reading stdin, will quit now..");
            global.quit_flag = PJ_TRUE;
            break;
        }

        if (line[0] == 'q') {
            global.quit_flag = PJ_TRUE;
        } else if (line[0] == 'd') {
            pj_bool_t detail = (line[1] == 'd');
            pjsip_endpt_dump(global.endpt, detail);
#if STATEFUL
            pjsip_tsx_layer_dump(detail);
#endif
        }
    }

    pj_thread_join(global.thread);

#else
    puts("\nPress Ctrl-C to quit\n");
    for (;;) {
        pj_time_val delay = {0, 0};
        pjsip_endpt_handle_events(global.endpt, &delay);
    }
#endif

    destroy_stack();

    return 0;
}

