/* $Id$ */
/* 
 * Copyright (C) 2008-2009 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 
 */
#include <pjlib-util/stun_simple.h>
#include <pjlib-util/errno.h>
#include <pj/log.h>
#include <pj/os.h>
#include <pj/pool.h>
#include <pj/rand.h>
#include <pj/sock_select.h>
#include <pj/string.h>


enum { MAX_REQUEST = 4 };
static int stun_timer[] = {1000, 1000, 1000, 1000 };

#define THIS_FILE	"stun_client.c"
#define LOG_ADDR(addr)	pj_inet_ntoa(addr.sin_addr), pj_ntohs(addr.sin_port)


PJ_DEF(pj_status_t) pjstun_get_mapped_addr( pj_pool_factory *pf,
					    int sock_cnt, pj_sock_t sock[],
					    const pj_str_t *srv1, int port1,
					    const pj_str_t *srv2, int port2,
					    pj_sockaddr_in mapped_addr[])
{
    pj_sockaddr_in srv_addr[2];
    int i, j, send_cnt = 0;
    pj_pool_t *pool;
    struct query_rec {
	struct {
	    pj_uint32_t	mapped_addr;
	    pj_uint32_t	mapped_port;
	} srv[2];
    } *rec;
    void       *out_msg;
    pj_size_t	out_msg_len;
    int wait_resp = 0;
    pj_status_t status;

    PJ_CHECK_STACK();

    /* Create pool. */
    pool = pj_pool_create(pf, "stun%p", 1024, 1024, NULL);
    if (!pool)
	return PJ_ENOMEM;


    /* Allocate client records */
    rec = (struct query_rec*) pj_pool_calloc(pool, sock_cnt, sizeof(*rec));
    if (!rec) {
	status = PJ_ENOMEM;
	goto on_error;
    }


    /* Create the outgoing BIND REQUEST message template */
    status = pjstun_create_bind_req( pool, &out_msg, &out_msg_len, 
				      pj_rand(), pj_rand());
    if (status != PJ_SUCCESS)
	goto on_error;

    /* Resolve servers. */
    status = pj_sockaddr_in_init(&srv_addr[0], srv1, (pj_uint16_t)port1);
    if (status != PJ_SUCCESS)
	goto on_error;

    status = pj_sockaddr_in_init(&srv_addr[1], srv2, (pj_uint16_t)port2);
    if (status != PJ_SUCCESS)
	goto on_error;

    /* Init mapped addresses to zero */
    pj_memset(mapped_addr, 0, sock_cnt * sizeof(pj_sockaddr_in));

    /* Main retransmission loop. */
    for (send_cnt=0; send_cnt<MAX_REQUEST; ++send_cnt) {
	pj_time_val next_tx, now;
	pj_fd_set_t r;
	int select_rc;

	PJ_FD_ZERO(&r);

	/* Send messages to servers that has not given us response. */
	for (i=0; i<sock_cnt && status==PJ_SUCCESS; ++i) {
	    for (j=0; j<2 && status==PJ_SUCCESS; ++j) {
		pjstun_msg_hdr *msg_hdr = (pjstun_msg_hdr*) out_msg;
                pj_ssize_t sent_len;

		if (rec[i].srv[j].mapped_port != 0)
		    continue;

		/* Modify message so that we can distinguish response. */
		msg_hdr->tsx[2] = pj_htonl(i);
		msg_hdr->tsx[3] = pj_htonl(j);

		/* Send! */
                sent_len = out_msg_len;
		status = pj_sock_sendto(sock[i], out_msg, &sent_len, 0,
					(pj_sockaddr_t*)&srv_addr[j], 
					sizeof(pj_sockaddr_in));
		if (status == PJ_SUCCESS)
		    ++wait_resp;
	    }
	}

	/* All requests sent.
	 * The loop below will wait for responses until all responses have
	 * been received (i.e. wait_resp==0) or timeout occurs, which then
	 * we'll go to the next retransmission iteration.
	 */

	/* Calculate time of next retransmission. */
	pj_gettimeofday(&next_tx);
	next_tx.sec += (stun_timer[send_cnt]/1000);
	next_tx.msec += (stun_timer[send_cnt]%1000);
	pj_time_val_normalize(&next_tx);

	for (pj_gettimeofday(&now), select_rc=1; 
	     status==PJ_SUCCESS && select_rc>=1 && wait_resp>0 
	       && PJ_TIME_VAL_LT(now, next_tx); 
	     pj_gettimeofday(&now)) 
	{
	    pj_time_val timeout;

	    timeout = next_tx;
	    PJ_TIME_VAL_SUB(timeout, now);

	    for (i=0; i<sock_cnt; ++i) {
		PJ_FD_SET(sock[i], &r);
	    }

	    select_rc = pj_sock_select(PJ_IOQUEUE_MAX_HANDLES, &r, NULL, NULL, &timeout);
	    if (select_rc < 1)
		continue;

	    for (i=0; i<sock_cnt; ++i) {
		int sock_idx, srv_idx;
                pj_ssize_t len;
		pjstun_msg msg;
		pj_sockaddr_in addr;
		int addrlen = sizeof(addr);
		pjstun_mapped_addr_attr *attr;
		char recv_buf[128];

		if (!PJ_FD_ISSET(sock[i], &r))
		    continue;

                len = sizeof(recv_buf);
		status = pj_sock_recvfrom( sock[i], recv_buf, 
				           &len, 0,
				           (pj_sockaddr_t*)&addr,
					   &addrlen);

		if (status != PJ_SUCCESS) {
		    char errmsg[PJ_ERR_MSG_SIZE];

		    PJ_LOG(4,(THIS_FILE, "recvfrom() error ignored: %s",
			      pj_strerror(status, errmsg,sizeof(errmsg)).ptr));

		    /* Ignore non-PJ_SUCCESS status.
		     * It possible that other SIP entity is currently 
		     * sending SIP request to us, and because SIP message
		     * is larger than STUN, we could get EMSGSIZE when
		     * we call recvfrom().
		     */
		    status = PJ_SUCCESS;
		    continue;
		}

		status = pjstun_parse_msg(recv_buf, len, &msg);
		if (status != PJ_SUCCESS) {
		    char errmsg[PJ_ERR_MSG_SIZE];

		    PJ_LOG(4,(THIS_FILE, "STUN parsing error ignored: %s",
			      pj_strerror(status, errmsg,sizeof(errmsg)).ptr));

		    /* Also ignore non-successful parsing. This may not
		     * be STUN response at all. See the comment above.
		     */
		    status = PJ_SUCCESS;
		    continue;
		}

		sock_idx = pj_ntohl(msg.hdr->tsx[2]);
		srv_idx = pj_ntohl(msg.hdr->tsx[3]);

		if (sock_idx<0 || sock_idx>=sock_cnt || srv_idx<0 || srv_idx>=2) {
		    status = PJLIB_UTIL_ESTUNININDEX;
		    continue;
		}

		if (pj_ntohs(msg.hdr->type) != PJSTUN_BINDING_RESPONSE) {
		    status = PJLIB_UTIL_ESTUNNOBINDRES;
		    continue;
		}

		/* From this part, we consider the packet as a valid STUN
		 * response for our request.
		 */
		--wait_resp;

		if (pjstun_msg_find_attr(&msg, PJSTUN_ATTR_ERROR_CODE) != NULL) {
		    status = PJLIB_UTIL_ESTUNRECVERRATTR;
		    continue;
		}

		attr = (pjstun_mapped_addr_attr*) 
		       pjstun_msg_find_attr(&msg, PJSTUN_ATTR_MAPPED_ADDR);
		if (!attr) {
		    status = PJLIB_UTIL_ESTUNNOMAP;
		    continue;
		}

		rec[sock_idx].srv[srv_idx].mapped_addr = attr->addr;
		rec[sock_idx].srv[srv_idx].mapped_port = attr->port;
	    }
	}

	/* The best scenario is if all requests have been replied.
	 * Then we don't need to go to the next retransmission iteration.
	 */
	if (wait_resp <= 0)
	    break;
    }

    for (i=0; i<sock_cnt && status==PJ_SUCCESS; ++i) {
	if (rec[i].srv[0].mapped_addr == rec[i].srv[1].mapped_addr &&
	    rec[i].srv[0].mapped_port == rec[i].srv[1].mapped_port)
	{
	    mapped_addr[i].sin_family = pj_AF_INET();
	    mapped_addr[i].sin_addr.s_addr = rec[i].srv[0].mapped_addr;
	    mapped_addr[i].sin_port = (pj_uint16_t)rec[i].srv[0].mapped_port;

	    if (rec[i].srv[0].mapped_addr == 0 || rec[i].srv[0].mapped_port == 0) {
		status = PJLIB_UTIL_ESTUNNOTRESPOND;
		break;
	    }
	} else {
	    status = PJLIB_UTIL_ESTUNSYMMETRIC;
	    break;
	}
    }

    pj_pool_release(pool);

    return status;

on_error:
    if (pool) pj_pool_release(pool);
    return status;
}