libpurple/protocols/qq/qq_network.c

/**
 * @file qq_network.c
 *
 * purple
 *
 * Purple is the legal property of its developers, whose names are too numerous
 * to list here.  Please refer to the COPYRIGHT file distributed with this
 * source distribution.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
 */

#include "cipher.h"
#include "debug.h"
#include "internal.h"

#ifdef _WIN32
#define random rand
#define srandom srand
#endif

#include "buddy_info.h"
#include "buddy_list.h"
#include "buddy_opt.h"
#include "buddy_status.h"
#include "group_free.h"
#include "char_conv.h"
#include "crypt.h"
#include "group_network.h"
#include "header_info.h"
#include "keep_alive.h"
#include "im.h"
#include "login_logout.h"
#include "packet_parse.h"
#include "qq_network.h"
#include "qq_trans.h"
#include "sys_msg.h"
#include "utils.h"

/* set QQ_RECONNECT_MAX to 1, when test reconnecting */
#define QQ_RECONNECT_MAX					4
#define QQ_RECONNECT_INTERVAL		5000

static gboolean set_new_server(qq_data *qd)
{
	gint count;
	gint index;
	GList *it = NULL;
	
 	g_return_val_if_fail(qd != NULL, FALSE);

	if (qd->servers == NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Server list is NULL\n");
		return FALSE;
	}

	if (qd->real_hostname) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free real_hostname\n");
		g_free(qd->real_hostname);
		qd->real_hostname = NULL;
	}

	/* remove server used before */
	if (qd->server_name != NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ",
			"Remove previous server [%s]\n", qd->server_name);
   		qd->servers = g_list_remove(qd->servers, qd->server_name);
   		qd->server_name = NULL;
    }
	
	count = g_list_length(qd->servers);
	purple_debug(PURPLE_DEBUG_INFO, "QQ", "Server list has %d\n", count);
	if (count <= 0) {
		/* no server left, disconnect when result is false */
		qd->servers = NULL;
		return FALSE;
	}
	
	/* get new server */
	index  = random() % count;
	it = g_list_nth(qd->servers, index);
    qd->server_name = it->data;		/* do not free server_name */
    if (qd->server_name == NULL || strlen(qd->server_name) <= 0 ) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Server name at %d is empty\n", index);
		return FALSE;
	}

	qd->real_hostname = g_strdup(qd->server_name);
	qd->real_port = qd->user_port;
	
 	qd->reconnect_times = QQ_RECONNECT_MAX;

	purple_debug(PURPLE_DEBUG_INFO, "QQ",
		"set new server to %s:%d\n", qd->real_hostname, qd->real_port);
	return TRUE;
}

/* QQ 2003iii uses double MD5 for the pwkey to get the session key */
static guint8 *encrypt_account_password(const gchar *pwd)
{
	PurpleCipher *cipher;
	PurpleCipherContext *context;

	guchar pwkey_tmp[QQ_KEY_LENGTH];

	cipher = purple_ciphers_find_cipher("md5");
	context = purple_cipher_context_new(cipher, NULL);
	purple_cipher_context_append(context, (guchar *) pwd, strlen(pwd));
	purple_cipher_context_digest(context, sizeof(pwkey_tmp), pwkey_tmp, NULL);
	purple_cipher_context_destroy(context);
	context = purple_cipher_context_new(cipher, NULL);
	purple_cipher_context_append(context, pwkey_tmp, QQ_KEY_LENGTH);
	purple_cipher_context_digest(context, sizeof(pwkey_tmp), pwkey_tmp, NULL);
	purple_cipher_context_destroy(context);

	return g_memdup(pwkey_tmp, QQ_KEY_LENGTH);
}

/* default process, decrypt and dump */
static void process_cmd_unknow(PurpleConnection *gc, guint8 *buf, gint buf_len, guint16 cmd, guint16 seq)
{
	qq_data *qd;
	guint8 *data;
	gint data_len;
	gchar *msg_utf8 = NULL;

	g_return_if_fail(buf != NULL && buf_len != 0);

	qq_show_packet("Processing unknown packet", buf, buf_len);

	qd = (qq_data *) gc->proto_data;

	data_len = buf_len;
	data = g_newa(guint8, data_len);
	memset(data, 0, data_len);
	if ( !qq_decrypt(buf, buf_len, qd->session_key, data, &data_len )) {
		purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Fail decrypt packet with default process\n");
		return;
	}
	
	qq_hex_dump(PURPLE_DEBUG_WARNING, "QQ",
			data, data_len,
			">>> [%d] %s -> [default] decrypt and dump",
			seq, qq_get_cmd_desc(cmd));

	msg_utf8 = try_dump_as_gbk(data, data_len);
	if (msg_utf8) {
		g_free(msg_utf8);
	}
}

static gint packet_get_header(guint8 *header_tag,  guint16 *source_tag,
	guint16 *cmd, guint16 *seq, guint8 *buf)
{
	gint bytes = 0;
	bytes += qq_get8(header_tag, buf + bytes);
	bytes += qq_get16(source_tag, buf + bytes);
	bytes += qq_get16(cmd, buf + bytes);
	bytes += qq_get16(seq, buf + bytes);
	return bytes;
}

/* check whether one sequence number is duplicated or not
 * return TRUE if it is duplicated, otherwise FALSE */
static gboolean packet_is_dup(qq_data *qd, guint16 seq)
{
	guint8 *byte, mask;

	g_return_val_if_fail(qd != NULL, FALSE);

	byte = &(qd->rcv_window[seq / 8]);
	mask = (1 << (seq % 8));

	if ((*byte) & mask)
		return TRUE;	/* check mask */
	(*byte) |= mask;
	return FALSE;		/* set mask */
}

static gboolean packet_check_ack(qq_data *qd, guint16 seq)
{
	gpointer trans;

	g_return_val_if_fail(qd != NULL, FALSE);

	trans = qq_send_trans_find(qd, seq);
	if (trans == NULL) {
		return FALSE;
	}
	
	qq_send_trans_remove(qd, trans);
	return TRUE;
}

static gboolean reconnect_later_cb(gpointer data)
{
	PurpleConnection *gc;
	qq_data *qd;

	gc = (PurpleConnection *) data;
	g_return_val_if_fail(gc != NULL && gc->proto_data != NULL, FALSE);
	qd = (qq_data *) gc->proto_data;

	qd->reconnect_timeout = 0;

	qq_connect(gc->account);
	return FALSE;	/* timeout callback stops */
}

static void reconnect_later(PurpleConnection *gc)
{
	qq_data *qd;

	g_return_if_fail(gc != NULL && gc->proto_data != NULL);
	qd = (qq_data *) gc->proto_data;

	qd->reconnect_times--;
	if (qd->reconnect_times < 0) {
		if ( set_new_server(qd) != TRUE) {
			purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
					_("Failed to connect server"));
			return;
		}
	}

	purple_debug(PURPLE_DEBUG_INFO, "QQ",
		"Reconnect to server %s:%d next retries %d in %d ms\n",
		qd->real_hostname, qd->real_port,
		qd->reconnect_times, QQ_RECONNECT_INTERVAL);

	qd->reconnect_timeout = purple_timeout_add(QQ_RECONNECT_INTERVAL,
		reconnect_later_cb, gc);
}

static void process_cmd_server(
	PurpleConnection *gc, guint16 cmd, guint16 seq, guint8 *data, gint data_len)
{
	/* now process the packet */
	switch (cmd) {
		case QQ_CMD_RECV_IM:
			qq_process_recv_im(data, data_len, seq, gc);
			break;
		case QQ_CMD_RECV_MSG_SYS:
			qq_process_msg_sys(data, data_len, seq, gc);
			break;
		case QQ_CMD_RECV_MSG_FRIEND_CHANGE_STATUS:
			qq_process_friend_change_status(data, data_len, gc);
			break;
		default:
			process_cmd_unknow(gc, data, data_len, cmd, seq);
			break;
	}
}

static void process_cmd_reply(
	PurpleConnection *gc, guint16 cmd, guint16 seq, guint8 *data, gint data_len)
{
	/* now process the packet */
	switch (cmd) {
		case QQ_CMD_KEEP_ALIVE:
			qq_process_keep_alive_reply(data, data_len, gc);
			break;
		case QQ_CMD_UPDATE_INFO:
			qq_process_modify_info_reply(data, data_len, gc);
			break;
		case QQ_CMD_ADD_FRIEND_WO_AUTH:
			qq_process_add_buddy_reply(data, data_len, seq, gc);
			break;
		case QQ_CMD_DEL_FRIEND:
			qq_process_remove_buddy_reply(data, data_len, gc);
			break;
		case QQ_CMD_REMOVE_SELF:
			qq_process_remove_self_reply(data, data_len, gc);
			break;
		case QQ_CMD_BUDDY_AUTH:
			qq_process_add_buddy_auth_reply(data, data_len, gc);
			break;
		case QQ_CMD_GET_USER_INFO:
			qq_process_get_info_reply(data, data_len, gc);
			break;
		case QQ_CMD_CHANGE_ONLINE_STATUS:
			qq_process_change_status_reply(data, data_len, gc);
			break;
		case QQ_CMD_SEND_IM:
			qq_process_send_im_reply(data, data_len, gc);
			break;
		case QQ_CMD_LOGIN:
			qq_process_login_reply(data, data_len, gc);
			break;
		case QQ_CMD_GET_FRIENDS_LIST:
			qq_process_get_buddies_list_reply(data, data_len, gc);
			break;
		case QQ_CMD_GET_FRIENDS_ONLINE:
			qq_process_get_buddies_online_reply(data, data_len, gc);
			break;
		case QQ_CMD_GROUP_CMD:
			qq_process_group_cmd_reply(data, data_len, seq, gc);
			break;
		case QQ_CMD_GET_ALL_LIST_WITH_GROUP:
			qq_process_get_all_list_with_group_reply(data, data_len, gc);
			break;
		case QQ_CMD_GET_LEVEL:
			qq_process_get_level_reply(data, data_len, gc);
			break;
		case QQ_CMD_REQUEST_LOGIN_TOKEN:
			qq_process_request_login_token_reply(data, data_len, gc);
			break;
		default:
			process_cmd_unknow(gc, data, data_len, cmd, seq);
			break;
	}
}

/* process the incoming packet from qq_pending */
static void packet_process(PurpleConnection *gc, guint8 *buf, gint buf_len)
{
	qq_data *qd;
	gint bytes, bytes_not_read;

	gboolean prev_login_status;
	guint8 *new_data;
	gint new_data_len;
	
	guint8 header_tag;
	guint16 source_tag;
	guint16 cmd;
	guint16 seq;		/* May be ack_seq or send_seq, depends on cmd */

	gboolean is_reply;

	g_return_if_fail(buf != NULL && buf_len > 0);

	qd = (qq_data *) gc->proto_data;

	prev_login_status = qd->logged_in;

	/* Len, header and tail tag have been checked before */
	bytes = 0;
	bytes += packet_get_header(&header_tag, &source_tag, &cmd, &seq, buf + bytes);

	if (QQ_DEBUG) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ",
				"==> [%05d] 0x%04X %s, from (0x%04X %s)\n",
				seq, cmd, qq_get_cmd_desc(cmd), source_tag, qq_get_source_str(source_tag));
	}
	
	bytes_not_read = buf_len - bytes - 1;

	/* ack packet, we need to update send tranactions */
	/* we do not check duplication for server ack */
	is_reply = packet_check_ack(qd, seq);
	if ( !is_reply ) {
		if ( !qd->logged_in ) {
			/* packets before login */
			qq_rcv_trans_push(qd, cmd, seq, buf + bytes, bytes_not_read);
			return;	/* do not process it now */
		}
		
		/* server intiated packet, we need to send ack and check duplicaion 
		 * this must be put after processing b4_packet
		 * as these packets will be passed in twice */
		if (packet_is_dup(qd, seq)) {
			purple_debug(PURPLE_DEBUG_WARNING,
					"QQ", "dup [%05d] %s, discard...\n", seq, qq_get_cmd_desc(cmd));
			return;
		}
		process_cmd_server(gc, cmd, seq, buf + bytes, bytes_not_read);
		return;
	}

	/* this is the length of all the encrypted data (also remove tail tag */
	process_cmd_reply(gc, cmd, seq, buf + bytes, bytes_not_read);

	/* check is redirect or not, and do it now */
	if (qd->is_redirect) {
	 	/* free resource except real_hostname and port */
		qq_disconnect(gc);
	 	qd->reconnect_times = QQ_RECONNECT_MAX;
		reconnect_later(gc);
		return;
	}

	if (prev_login_status != qd->logged_in && qd->logged_in == TRUE) {
		/* logged_in, but we have packets before login */
		new_data = g_newa(guint8, MAX_PACKET_SIZE);
		while (1) {
			memset(new_data, 0, MAX_PACKET_SIZE);
			new_data_len = qq_rcv_trans_pop(qd, &cmd, &seq, new_data, MAX_PACKET_SIZE);
			if (new_data_len < 0) {
				break;
			}
			if (new_data_len == 0) {
				continue;
			}
			process_cmd_reply(gc, seq, cmd, new_data, new_data_len);
		}
	}
}

static void tcp_pending(gpointer data, gint source, PurpleInputCondition cond)
{
	PurpleConnection *gc;
	qq_data *qd;
	guint8 buf[1024];		/* set to 16 when test  tcp_rxqueue */
	gint buf_len;
	gint bytes;
	
	guint8 *pkt;
	guint16 pkt_len;
	
	gchar *error_msg;
	guint8 *jump;
	gint jump_len;

	gc = (PurpleConnection *) data;
	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	if(cond != PURPLE_INPUT_READ) {
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("Socket error"));
		return;
	}

	qd = (qq_data *) gc->proto_data;
	
	/* test code, not using tcp_rxqueue
	memset(pkt,0, sizeof(pkt));
	buf_len = read(qd->fd, pkt, sizeof(pkt));
	if (buf_len > 2) {
		packet_process(gc, pkt + 2, buf_len - 2);
	}
	return;
	*/
	
	buf_len = read(qd->fd, buf, sizeof(buf));
	if (buf_len < 0) {
		if (errno == EAGAIN)
			/* No worries */
			return;

		error_msg = g_strdup_printf(_("Lost connection with server:\n%d, %s"), errno, g_strerror(errno));
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR, error_msg);
		g_free(error_msg);
		return;
	} else if (buf_len == 0) {
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("Server closed the connection."));
		return;
	}

	gc->last_received = time(NULL);
	purple_debug(PURPLE_DEBUG_INFO, "TCP_PENDING",
			   "Read %d bytes from socket, rxlen is %d\n", buf_len, qd->tcp_rxlen);
	qd->tcp_rxqueue = g_realloc(qd->tcp_rxqueue, buf_len + qd->tcp_rxlen);
	memcpy(qd->tcp_rxqueue + qd->tcp_rxlen, buf, buf_len);
	qd->tcp_rxlen += buf_len;
	
	pkt = g_newa(guint8, MAX_PACKET_SIZE);
	while (1) {
		if (qd->tcp_rxlen < QQ_TCP_HEADER_LENGTH) {
			break;
		}
		
		bytes = 0;
		bytes += qq_get16(&pkt_len, qd->tcp_rxqueue + bytes);
		if (qd->tcp_rxlen < pkt_len) {
			break;
		}

		purple_debug(PURPLE_DEBUG_INFO, "TCP_PENDING",
				   "Packet len is %d bytes, rxlen is %d\n", pkt_len, qd->tcp_rxlen);

		if ( pkt_len < QQ_TCP_HEADER_LENGTH
		    || *(qd->tcp_rxqueue + bytes) != QQ_PACKET_TAG
			|| *(qd->tcp_rxqueue + pkt_len - 1) != QQ_PACKET_TAIL) {
			/* HEY! This isn't even a QQ. What are you trying to pull? */

			purple_debug(PURPLE_DEBUG_ERROR, "TCP_PENDING",
				 "Packet error, failed to check header and tail tag\n");

			jump = memchr(qd->tcp_rxqueue + 1, QQ_PACKET_TAIL, qd->tcp_rxlen - 1);
			if ( !jump ) {
				purple_debug(PURPLE_DEBUG_INFO, "TCP_PENDING",
				 	"Failed to find next QQ_PACKET_TAIL, clear receive buffer\n");
				g_free(qd->tcp_rxqueue);
				qd->tcp_rxqueue = NULL;
				qd->tcp_rxlen = 0;
				return;
			}

			/* jump and over QQ_PACKET_TAIL */
			jump_len = (jump - qd->tcp_rxqueue) + 1;
			purple_debug(PURPLE_DEBUG_INFO, "TCP_PENDING",
				"Find next QQ_PACKET_TAIL at %d, jump %d bytes\n", jump_len, jump_len + 1);
			g_memmove(qd->tcp_rxqueue, jump, qd->tcp_rxlen - jump_len);
			qd->tcp_rxlen -= jump_len;
			continue;
		}

		memset(pkt, 0, MAX_PACKET_SIZE);
		g_memmove(pkt, qd->tcp_rxqueue + bytes, pkt_len - bytes);
		
		/* jump to next packet */
		qd->tcp_rxlen -= pkt_len;
		if (qd->tcp_rxlen) {
			purple_debug(PURPLE_DEBUG_ERROR, "TCP_PENDING",
			 	"shrink tcp_rxqueue to %d\n", qd->tcp_rxlen);		
			jump = g_memdup(qd->tcp_rxqueue + pkt_len, qd->tcp_rxlen);
			g_free(qd->tcp_rxqueue);
			qd->tcp_rxqueue = jump;
		} else {
			purple_debug(PURPLE_DEBUG_ERROR, "TCP_PENDING",
			 	"free tcp_rxqueue\n");		
			g_free(qd->tcp_rxqueue);
			qd->tcp_rxqueue = NULL;
		}

		if (pkt == NULL) {
			continue;
		}
		/* do not call packet_process before jump 
		 * packet_process may call disconnect and destory tcp_rxqueue */
		packet_process(gc, pkt, pkt_len - bytes);
	}
}

static void udp_pending(gpointer data, gint source, PurpleInputCondition cond)
{
	PurpleConnection *gc;
	qq_data *qd;
	guint8 *buf;
	gint buf_len;

	gc = (PurpleConnection *) data;
	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	if(cond != PURPLE_INPUT_READ) {
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("Socket error"));
		return;
	}

	qd = (qq_data *) gc->proto_data;
	g_return_if_fail(qd->fd >= 0);
	
	buf = g_newa(guint8, MAX_PACKET_SIZE);

	/* here we have UDP proxy suppport */
	buf_len = read(qd->fd, buf, MAX_PACKET_SIZE);
	if (buf_len <= 0) {
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("Unable to read from socket"));
		return;
	}

	gc->last_received = time(NULL);

	if (buf_len < QQ_UDP_HEADER_LENGTH) {
		if (buf[0] != QQ_PACKET_TAG || buf[buf_len - 1] != QQ_PACKET_TAIL) {
			qq_hex_dump(PURPLE_DEBUG_ERROR, "UDP_PENDING",
					buf, buf_len,
					"Received packet is too short, or no header and tail tag");
			return;
		}
	}
	
	packet_process(gc, buf, buf_len);
}

static gint udp_send_out(qq_data *qd, guint8 *data, gint data_len)
{
	gint ret;

	g_return_val_if_fail(qd != NULL && qd->fd >= 0 && data != NULL && data_len > 0, -1);

	purple_debug(PURPLE_DEBUG_INFO, "QQ", "Send %d bytes to socket %d\n", data_len, qd->fd);

	errno = 0;
	ret = send(qd->fd, data, data_len, 0);
	if (ret < 0 && errno == EAGAIN) {
		return ret;
	}
	
	if (ret < 0) {
		/* TODO: what to do here - do we really have to disconnect? */
		purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Send failed: %d, %s\n", errno, g_strerror(errno));
		purple_connection_error_reason(qd->gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR, g_strerror(errno));
	}
	return ret;
}

static void tcp_can_write(gpointer data, gint source, PurpleInputCondition cond)
{
	qq_data *qd = data;
	int ret, writelen;

	writelen = purple_circ_buffer_get_max_read(qd->tcp_txbuf);
	if (writelen == 0) {
		purple_input_remove(qd->tx_handler);
		qd->tx_handler = 0;
		return;
	}

	ret = write(qd->fd, qd->tcp_txbuf->outptr, writelen);
	purple_debug(PURPLE_DEBUG_ERROR, "TCP_CAN_WRITE",
		"total %d bytes is sent %d\n", writelen, ret);

	if (ret < 0 && errno == EAGAIN)
		return;
	else if (ret < 0) {
		/* TODO: what to do here - do we really have to disconnect? */
		purple_connection_error_reason(qd->gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
		                               _("Write Error"));
		return;
	}

	purple_circ_buffer_mark_read(qd->tcp_txbuf, ret);
}

static gint tcp_send_out(qq_data *qd, guint8 *data, gint data_len)
{
	gint ret;

	g_return_val_if_fail(qd != NULL && qd->fd >= 0 && data != NULL && data_len > 0, -1);

	/*
	 * purple_debug(PURPLE_DEBUG_INFO, "TCP_SEND_OUT", "Send %d bytes to socket %d\n", data_len, qd->fd);
	 */

	if (qd->tx_handler == 0) {
		ret = write(qd->fd, data, data_len);
	} else {
		ret = -1;
		errno = EAGAIN;
	}

	purple_debug(PURPLE_DEBUG_INFO, "TCP_SEND_OUT",
		"Socket %d, total %d bytes is sent %d\n", qd->fd, data_len, ret);
	if (ret < 0 && errno == EAGAIN) {
		/* socket is busy, send later */
		/*
		 * purple_debug(PURPLE_DEBUG_INFO, "TCP_SEND_OUT", "Socket is busy and send later\n");
		 */
		ret = 0;
	} else if (ret <= 0) {
		/* TODO: what to do here - do we really have to disconnect? */
		purple_debug(PURPLE_DEBUG_ERROR, "TCP_SEND_OUT",
			"Send to socket %d failed: %d, %s\n", qd->fd, errno, g_strerror(errno));
		purple_connection_error_reason(qd->gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR, g_strerror(errno));
		return ret;
	}

	if (ret < data_len) {
		purple_debug(PURPLE_DEBUG_INFO, "TCP_SEND_OUT",
			"Add %d bytes to buffer\n", data_len - ret);
		if (qd->tx_handler == 0) {
			qd->tx_handler = purple_input_add(qd->fd, PURPLE_INPUT_WRITE, tcp_can_write, qd);
		}
		purple_circ_buffer_append(qd->tcp_txbuf, data + ret, data_len - ret);
	}
	return ret;
}

static gboolean trans_timeout(gpointer data)
{
	PurpleConnection *gc;
	qq_data *qd;
	guint8 *buf;
	gint buf_len = 0;
	guint16 cmd;
	gint retries = 0;
	int index;
	
	gc = (PurpleConnection *) data;
	g_return_val_if_fail(gc != NULL && gc->proto_data != NULL, TRUE);

	qd = (qq_data *) gc->proto_data;
	
	index = 0;
	buf = g_newa(guint8, MAX_PACKET_SIZE);

	while (1) {
		if (index < 0) {
			/* next record is NULL */
			break;
		}
		/* purple_debug(PURPLE_DEBUG_ERROR, "QQ", "scan begin %d\n", index); */
		memset(buf, 0, MAX_PACKET_SIZE);
		buf_len = qq_send_trans_scan(qd, &index, buf, MAX_PACKET_SIZE, &cmd, &retries);
		if (buf_len <= 0) {
			/* curr record is empty, whole trans  is NULL */
			break;
		}
		/* index = -1, when get last record of transactions */
		
		/* purple_debug(PURPLE_DEBUG_ERROR, "QQ", "retries %d next index %d\n", retries, index); */
		if (retries > 0) {
			if (qd->use_tcp) {
				tcp_send_out(qd, buf, buf_len);
			} else {
				udp_send_out(qd, buf, buf_len);
			}
			continue;
		}

		/* retries <= 0 */
		switch (cmd) {
		case QQ_CMD_KEEP_ALIVE:
			if (qd->logged_in) {
				purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Connection lost!\n");
				purple_connection_error_reason(gc,
					PURPLE_CONNECTION_ERROR_NETWORK_ERROR, _("Connection lost"));
				qd->logged_in = FALSE;
			}
			break;
		case QQ_CMD_LOGIN:
		case QQ_CMD_REQUEST_LOGIN_TOKEN:
			if (!qd->logged_in)	{
				/* cancel login progress */
				purple_connection_error_reason(gc,
					PURPLE_CONNECTION_ERROR_NETWORK_ERROR, _("Login failed, no reply"));
			}
			break;
		default:
			purple_debug(PURPLE_DEBUG_WARNING, "QQ", 
				"%s packet lost.\n", qq_get_cmd_desc(cmd));
		}
	}

	return TRUE;		/* if return FALSE, timeout callback stops */
}

/* the callback function after socket is built
 * we setup the qq protocol related configuration here */
static void qq_connect_cb(gpointer data, gint source, const gchar *error_message)
{
	qq_data *qd;
	PurpleConnection *gc;
	gchar *conn_msg;
	const gchar *passwd;

	gc = (PurpleConnection *) data;

	if (!PURPLE_CONNECTION_IS_VALID(gc)) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ_CONN", "Invalid connection\n");
		close(source);
		return;
	}

	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	qd = (qq_data *) gc->proto_data;

	/* Connect is now complete; clear the PurpleProxyConnectData */
	qd->connect_data = NULL;

	if (source < 0) {	/* socket returns -1 */
		purple_debug(PURPLE_DEBUG_INFO, "QQ_CONN", "Invalid connection, source is < 0\n");
		qq_disconnect(gc);
		reconnect_later(gc);
		return;
	}

	/* _qq_show_socket("Got login socket", source); */

	/* QQ use random seq, to minimize duplicated packets */
	srandom(time(NULL));
	qd->send_seq = random() & 0x0000ffff;
	qd->fd = source;
	qd->logged_in = FALSE;
	qd->channel = 1;
	qd->uid = strtol(purple_account_get_username(purple_connection_get_account(gc)), NULL, 10);

	/* now generate md5 processed passwd */
	passwd = purple_account_get_password(purple_connection_get_account(gc));
	g_return_if_fail(qd->pwkey == NULL);
	qd->pwkey = encrypt_account_password(passwd);

	g_return_if_fail(qd->resend_timeout == 0);
	/* call trans_timeout every 5 seconds */
	qd->resend_timeout = purple_timeout_add(5000, trans_timeout, gc);
	
	if (qd->use_tcp)
		gc->inpa = purple_input_add(qd->fd, PURPLE_INPUT_READ, tcp_pending, gc);
	else
		gc->inpa = purple_input_add(qd->fd, PURPLE_INPUT_READ, udp_pending, gc);

	/* Update the login progress status display */
	conn_msg = g_strdup_printf("Login as %d", qd->uid);
	purple_connection_update_progress(gc, conn_msg, QQ_CONNECT_STEPS - 1, QQ_CONNECT_STEPS);
	g_free(conn_msg);

	qq_send_packet_request_login_token(gc);
}

static void udp_can_write(gpointer data, gint source, PurpleInputCondition cond)
{
	PurpleConnection *gc;
	qq_data *qd;
	socklen_t len;
	int error=0, ret;

	gc = (PurpleConnection *) data;
	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	qd = (qq_data *) gc->proto_data;


	purple_debug_info("proxy", "Connected.\n");

	/*
	 * getsockopt after a non-blocking connect returns -1 if something is
	 * really messed up (bad descriptor, usually). Otherwise, it returns 0 and
	 * error holds what connect would have returned if it blocked until now.
	 * Thus, error == 0 is success, error == EINPROGRESS means "try again",
	 * and anything else is a real error.
	 *
	 * (error == EINPROGRESS can happen after a select because the kernel can
	 * be overly optimistic sometimes. select is just a hint that you might be
	 * able to do something.)
	 */
	len = sizeof(error);
	ret = getsockopt(source, SOL_SOCKET, SO_ERROR, &error, &len);
	if (ret == 0 && error == EINPROGRESS)
		return; /* we'll be called again later */
		
	purple_input_remove(qd->tx_handler);
	qd->tx_handler = 0;
	if (ret < 0 || error != 0) {
		if(ret != 0) 
			error = errno;

		close(source);

		purple_debug_error("proxy", "getsockopt SO_ERROR check: %s\n", g_strerror(error));

		qq_connect_cb(gc, -1, _("Unable to connect"));
		return;
	}

	qq_connect_cb(gc, source, NULL);
}

static void udp_host_resolved(GSList *hosts, gpointer data, const char *error_message) {
	PurpleConnection *gc;
	qq_data *qd;
	struct sockaddr server_addr;
	int addr_size;
	gint fd = -1;
	int flags;

	gc = (PurpleConnection *) data;
	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	qd = (qq_data *) gc->proto_data;

	/* udp_query_data must be set as NULL.
	 * Otherwise purple_dnsquery_destroy in qq_disconnect cause glib double free error */
	qd->udp_query_data = NULL;

	if (!hosts || !hosts->data) {
		purple_connection_error_reason(gc,
			PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
			_("Couldn't resolve host"));
		return;
	}

	addr_size = GPOINTER_TO_INT(hosts->data);
	hosts = g_slist_remove(hosts, hosts->data);
	memcpy(&server_addr, hosts->data, addr_size);
	g_free(hosts->data);
	
	hosts = g_slist_remove(hosts, hosts->data);
	while(hosts) {
		hosts = g_slist_remove(hosts, hosts->data);
		g_free(hosts->data);
		hosts = g_slist_remove(hosts, hosts->data);
	}

	fd = socket(PF_INET, SOCK_DGRAM, 0);
	if (fd < 0) {
		purple_debug(PURPLE_DEBUG_ERROR, "QQ", 
				"Unable to create socket: %s\n", g_strerror(errno));
		return;
	}

	/* we use non-blocking mode to speed up connection */
	flags = fcntl(fd, F_GETFL);
	fcntl(fd, F_SETFL, flags | O_NONBLOCK);

	/* From Unix-socket-FAQ: http://www.faqs.org/faqs/unix-faq/socket/
	 *
	 * If a UDP socket is unconnected, which is the normal state after a
	 * bind() call, then send() or write() are not allowed, since no
	 * destination is available; only sendto() can be used to send data.
	 *   
	 * Calling connect() on the socket simply records the specified address
	 * and port number as being the desired communications partner. That
	 * means that send() or write() are now allowed; they use the destination
	 * address and port given on the connect call as the destination of packets.
	 */
	if (connect(fd, &server_addr, addr_size) >= 0) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Connected.\n");
		flags = fcntl(fd, F_GETFL);
		fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
		qq_connect_cb(gc, fd, NULL);
		return;
	}
	
	/* [EINPROGRESS]
	 *    The socket is marked as non-blocking and the connection cannot be 
	 *    completed immediately. It is possible to select for completion by 
	 *    selecting the socket for writing.
	 * [EINTR]
	 *    A signal interrupted the call. 
	 *    The connection is established asynchronously.
	 */
	if ((errno == EINPROGRESS) || (errno == EINTR)) {
			purple_debug(PURPLE_DEBUG_WARNING, "QQ", "Connect in asynchronous mode.\n");
			qd->tx_handler = purple_input_add(fd, PURPLE_INPUT_WRITE, udp_can_write, gc);
			return;
		}

	purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Connection failed: %d\n", g_strerror(errno));
	close(fd);
}

/* establish a generic QQ connection 
 * TCP/UDP, and direct/redirected */
void qq_connect(PurpleAccount *account)
{
	PurpleConnection *gc;
	qq_data *qd;
	gchar *conn_msg;

	gc = purple_account_get_connection(account);
	g_return_if_fail(gc != NULL && gc->proto_data != NULL);

	qd = (qq_data *) gc->proto_data;


	/* test set_new_server
	while (set_new_server(qd)) {
   		purple_debug(PURPLE_DEBUG_INFO, "QQ_TEST",
   			"New server %s:%d  Real server %s:%d\n",
   			qd->server_name, qd->user_port, qd->real_hostname, qd->real_port);
	}
	purple_debug(PURPLE_DEBUG_INFO, "QQ_TEST", "qd->servers %lu\n",
 			qd->servers);
 	exit(1);
	*/
	if (qd->server_name == NULL) {
		/* must be first call this function */
		if ( set_new_server(qd) != TRUE) {
			purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
					_("Failed to connect server"));
			return;
		}
	}

	if (qd->real_hostname == NULL || qd->real_port == 0) {
		purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("hostname is NULL or port is 0"));
		return;
	}

	conn_msg = g_strdup_printf( _("Connecting server %s, retries %d"),
		qd->real_hostname, qd->reconnect_times);
	purple_connection_update_progress(gc, conn_msg, 1, QQ_CONNECT_STEPS);
	g_free(conn_msg);

	if (qd->is_redirect) {
   		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Redirect to %s:%d\n",
   			qd->real_hostname, qd->real_port);
   	}
	qd->is_redirect = FALSE;

	qd->fd = -1;
	qd->tx_handler = 0;
	
	/* QQ connection via UDP/TCP. 
	* Now use Purple proxy function to provide TCP proxy support,
	* and qq_udp_proxy.c to add UDP proxy support (thanks henry) */
	if(qd->use_tcp) {
   		purple_debug(PURPLE_DEBUG_INFO, "QQ", "TCP Connect to %s:%d\n",
   			qd->real_hostname, qd->real_port);

		/* TODO: is there a good default grow size? */
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Create tcp_txbuf\n");
		qd->tcp_txbuf = purple_circ_buffer_new(0);

		qd->connect_data = purple_proxy_connect(NULL, account,
				qd->real_hostname, qd->real_port, qq_connect_cb, gc);
		if (qd->connect_data == NULL) {
			purple_connection_error_reason(gc, PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
				_("Unable to connect."));
		}
		return;
	}
	
	purple_debug(PURPLE_DEBUG_INFO, "QQ", "UDP Connect to %s:%d\n",
		qd->real_hostname, qd->real_port);

	g_return_if_fail(qd->udp_query_data == NULL);
	qd->udp_query_data = purple_dnsquery_a(qd->real_hostname, qd->real_port,
		udp_host_resolved, gc);
	if (qd->udp_query_data == NULL) {
		purple_connection_error_reason(qd->gc,
			PURPLE_CONNECTION_ERROR_NETWORK_ERROR,
			_("Could not resolve hostname"));
	}
}

/* clean up qq_data structure and all its components
 * always used before a redirectly connection */
void qq_disconnect(PurpleConnection *gc)
{
	qq_data *qd;

	g_return_if_fail(gc != NULL && gc->proto_data != NULL);
	qd = (qq_data *) gc->proto_data;

	purple_debug(PURPLE_DEBUG_INFO, "QQ", "Disconnecting ...\n");
	/* finish  all I/O */
	if (qd->fd >= 0 && qd->logged_in) {
		qq_send_packet_logout(gc);
	}

	if (qd->resend_timeout > 0) {
		purple_timeout_remove(qd->resend_timeout);
		qd->resend_timeout = 0;
	}

	if (gc->inpa > 0) {
		purple_input_remove(gc->inpa);
		gc->inpa = 0;
	}

	if (qd->fd >= 0) {
		close(qd->fd);
		qd->fd = -1;
	}

	if (qd->reconnect_timeout > 0) {
		purple_timeout_remove(qd->reconnect_timeout);
		qd->reconnect_timeout = 0;
	}

	if (qd->connect_data != NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "Cancel connect_data\n");
		purple_proxy_connect_cancel(qd->connect_data);
	}
	
	if(qd->tcp_txbuf != NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "destroy tcp_txbuf\n");
		purple_circ_buffer_destroy(qd->tcp_txbuf);
		qd->tcp_txbuf = NULL;
	}
	
	if (qd->tx_handler) {
		purple_input_remove(qd->tx_handler);
		qd->tx_handler = 0;
	}
	if (qd->tcp_rxqueue != NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "destroy tcp_rxqueue\n");
		g_free(qd->tcp_rxqueue);
		qd->tcp_rxqueue = NULL;
		qd->tcp_rxlen = 0;
	}
	
	if (qd->udp_query_data != NULL) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "destroy udp_query_data\n");
		purple_dnsquery_destroy(qd->udp_query_data);
		qd->udp_query_data = NULL;
	}

	memset(qd->rcv_window, 0, sizeof(qd->rcv_window));
	qq_rcv_trans_remove_all(qd);
	qq_send_trans_remove_all(qd);
	
	if (qd->inikey) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free inikey\n");
		g_free(qd->inikey);
		qd->inikey = NULL;
	}
	if (qd->pwkey) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free pwkey\n");
		g_free(qd->pwkey);
		qd->pwkey = NULL;
	}
	if (qd->session_key) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free session_key\n");
		g_free(qd->session_key);
		qd->session_key = NULL;
	}
	if (qd->session_md5) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free session_md5\n");
		g_free(qd->session_md5);
		qd->session_md5 = NULL;
	}
	if (qd->my_ip) {
		purple_debug(PURPLE_DEBUG_INFO, "QQ", "free my_ip\n");
		g_free(qd->my_ip);
		qd->my_ip = NULL;
	}

	qq_group_packets_free(qd);
	qq_group_free_all(qd);
	qq_add_buddy_request_free(qd);
	qq_info_query_free(qd);
	qq_buddies_list_free(gc->account, qd);
}

static gint encap(qq_data *qd, guint8 *buf, gint maxlen, guint16 cmd, guint16 seq, 
	guint8 *data, gint data_len)
{
	gint bytes = 0;
	g_return_val_if_fail(qd != NULL && buf != NULL && maxlen > 0, -1);
	
	if (data == NULL) {
		purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Fail encap packet, data is NULL\n");
		return -1;
	}
	if (data_len <= 0) {
		purple_debug(PURPLE_DEBUG_ERROR, "QQ", "Fail encap packet, data len <= 0\n");
		return -1;
	}

	/* QQ TCP packet has two bytes in the begining defines packet length
	 * so leave room here to store packet size */
	if (qd->use_tcp) {
		bytes += qq_put16(buf + bytes, 0x0000);
	}
	/* now comes the normal QQ packet as UDP */
	bytes += qq_put8(buf + bytes, QQ_PACKET_TAG);
	bytes += qq_put16(buf + bytes, QQ_CLIENT);
	bytes += qq_put16(buf + bytes, cmd);
	
	bytes += qq_put16(buf + bytes, seq);

	bytes += qq_put32(buf + bytes, qd->uid);
	bytes += qq_putdata(buf + bytes, data, data_len);
	bytes += qq_put8(buf + bytes, QQ_PACKET_TAIL);

	/* set TCP packet length at begin of the packet */
	if (qd->use_tcp) {
		qq_put16(buf, bytes);
	}

	return bytes;
}

gint qq_send_data(qq_data *qd, guint16 cmd, guint8 *data, gint data_len)
{
	guint8 *buf;
	gint buf_len;
	gint bytes_sent;
	gint seq;

	g_return_val_if_fail(qd != NULL, -1);
	g_return_val_if_fail(data != NULL && data_len > 0, -1);

	buf = g_newa(guint8, MAX_PACKET_SIZE);
	memset(buf, 0, MAX_PACKET_SIZE);
	seq = ++(qd->send_seq);
	buf_len = encap(qd, buf, MAX_PACKET_SIZE, cmd, seq, data, data_len);
	if (buf_len <= 0) {
		return -1;
	}

	if (qd->use_tcp) {
		bytes_sent = tcp_send_out(qd, buf, buf_len);
	} else {
		bytes_sent = udp_send_out(qd, buf, buf_len);
	}

	/* always need ack */
	qq_send_trans_append(qd, buf, buf_len, cmd, seq);

	if (QQ_DEBUG) {
		qq_show_packet("QQ_SEND_DATA", buf, buf_len);
		purple_debug(PURPLE_DEBUG_INFO, "QQ",
				"<== [%05d], %s, total %d bytes is sent %d\n", 
				seq, qq_get_cmd_desc(cmd), buf_len, bytes_sent);
	}
	return bytes_sent;
}

/* send the packet generated with the given cmd and data
 * return the number of bytes sent to socket if succeeds
 * return -1 if there is any error */
gint qq_send_cmd_detail(qq_data *qd, guint16 cmd, guint16 seq, gboolean need_ack,
	guint8 *data, gint data_len)
{
	guint8 *buf;
	gint buf_len;
	guint8 *encrypted_data;
	gint encrypted_len;
	gint bytes_sent;

	g_return_val_if_fail(qd != NULL && qd->session_key != NULL, -1);
	g_return_val_if_fail(data != NULL && data_len > 0, -1);

	encrypted_len = data_len + 16;	/* at most 16 bytes more */
	encrypted_data = g_newa(guint8, encrypted_len);

	qq_encrypt(data, data_len, qd->session_key, encrypted_data, &encrypted_len);

	buf = g_newa(guint8, MAX_PACKET_SIZE);
	memset(buf, 0, MAX_PACKET_SIZE);
	buf_len = encap(qd, buf, MAX_PACKET_SIZE, cmd, seq, encrypted_data, encrypted_len);
	if (buf_len <= 0) {
		return -1;
	}

	if (QQ_DEBUG) {
		qq_show_packet("QQ_SEND_CMD", buf, buf_len);
	}
	if (qd->use_tcp) {
		bytes_sent = tcp_send_out(qd, buf, buf_len);
	} else {
		bytes_sent = udp_send_out(qd, buf, buf_len);
	}
	
	/* if it does not need ACK, we send ACK manually several times */
	if (need_ack)  {
		qq_send_trans_append(qd, buf, buf_len, cmd, seq);
	}

	if (QQ_DEBUG) {
		qq_show_packet("QQ_SEND_CMD", buf, buf_len);
		purple_debug(PURPLE_DEBUG_INFO, "QQ",
				"<== [%05d], %s, total %d bytes is sent %d\n", 
				seq, qq_get_cmd_desc(cmd), buf_len, bytes_sent);
	}
	return bytes_sent;
}

gint qq_send_cmd(qq_data *qd, guint16 cmd, guint8 *data, gint data_len)
{
	g_return_val_if_fail(qd != NULL, -1);
	g_return_val_if_fail(data != NULL && data_len > 0, -1);

	qd->send_seq++;
	return qq_send_cmd_detail(qd, cmd, qd->send_seq, TRUE, data, data_len);
}