flap_connection.c

Linux下的多协议即时通讯程序源代码

/*
 * Purple's oscar protocol plugin
 * This file is the legal property of its developers.
 * Please see the AUTHORS file distributed alongside this file.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "oscar.h"

#include "eventloop.h"
#include "proxy.h"

#ifndef _WIN32
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#endif

#ifdef _WIN32
#include "win32dep.h"
#endif

/**
 * This sends a channel 1 SNAC containing the FLAP version.
 * The FLAP version is sent by itself at the beginning of every
 * connection to a FLAP server.  It is always the very first
 * packet sent by both the server and the client after the SYN,
 * SYN/ACK, ACK handshake.
 */
void
flap_connection_send_version(OscarData *od, FlapConnection *conn)
{
	FlapFrame *frame;

	frame = flap_frame_new(od, 0x01, 4);
	byte_stream_put32(&frame->data, 0x00000001);
	flap_connection_send(conn, frame);
}

/**
 * This sends a channel 1 FLAP containing the FLAP version and
 * the authentication cookie.  This is sent when connecting to
 * any FLAP server after the initial connection to the auth
 * server.  It is always the very first packet sent by both the
 * server and the client after the SYN, SYN/ACK, ACK handshake.
 */
void
flap_connection_send_version_with_cookie(OscarData *od, FlapConnection *conn, guint16 length, const guint8 *chipsahoy)
{
	FlapFrame *frame;
	GSList *tlvlist = NULL;

	frame = flap_frame_new(od, 0x01, 4 + 2 + 2 + length);
	byte_stream_put32(&frame->data, 0x00000001);
	aim_tlvlist_add_raw(&tlvlist, 0x0006, length, chipsahoy);
	aim_tlvlist_write(&frame->data, &tlvlist);
	aim_tlvlist_free(tlvlist);

	flap_connection_send(conn, frame);
}

static struct rateclass *
flap_connection_get_rateclass(FlapConnection *conn, guint16 family, guint16 subtype)
{
	GSList *tmp1;
	gconstpointer key;

	key = GUINT_TO_POINTER((family << 16) + subtype);

	for (tmp1 = conn->rateclasses; tmp1 != NULL; tmp1 = tmp1->next)
	{
		struct rateclass *rateclass;
		rateclass = tmp1->data;

		if (g_hash_table_lookup(rateclass->members, key))
			return rateclass;
	}

	return NULL;
}

/*
 * Attempt to calculate what our new current average would be if we
 * were to send a SNAC in this rateclass at the given time.
 */
static guint32
rateclass_get_new_current(FlapConnection *conn, struct rateclass *rateclass, struct timeval *now)
{
	unsigned long timediff; /* In milliseconds */

	timediff = (now->tv_sec - rateclass->last.tv_sec) * 1000 + (now->tv_usec - rateclass->last.tv_usec) / 1000;

	/* This formula is taken from the joscar API docs. Preesh. */
	return MIN(((rateclass->current * (rateclass->windowsize - 1)) + timediff) / rateclass->windowsize, rateclass->max);
}

static gboolean flap_connection_send_queued(gpointer data)
{
	FlapConnection *conn;
	struct timeval now;

	conn = data;
	gettimeofday(&now, NULL);

	while (!g_queue_is_empty(conn->queued_snacs))
	{
		QueuedSnac *queued_snac;
		struct rateclass *rateclass;

		queued_snac = g_queue_peek_head(conn->queued_snacs);

		rateclass = flap_connection_get_rateclass(conn, queued_snac->family, queued_snac->subtype);
		if (rateclass != NULL)
		{
			guint32 new_current;

			new_current = rateclass_get_new_current(conn, rateclass, &now);

			if (new_current < rateclass->alert + 100)
				/* (Add 100ms padding to account for inaccuracies in the calculation) */
				/* Not ready to send this SNAC yet--keep waiting. */
				return TRUE;

			rateclass->current = new_current;
			rateclass->last.tv_sec = now.tv_sec;
			rateclass->last.tv_usec = now.tv_usec;
		}

		flap_connection_send(conn, queued_snac->frame);
		g_free(queued_snac);
		g_queue_pop_head(conn->queued_snacs);
	}

	conn->queued_timeout = 0;
	return FALSE;
}

/**
 * This sends a channel 2 FLAP containing a SNAC.  The SNAC family and
 * subtype are looked up in the rate info for this connection, and if
 * sending this SNAC will induce rate limiting then we delay sending
 * of the SNAC by putting it into an outgoing holding queue.
 *
 * @param data The optional bytestream that makes up the data portion
 *        of this SNAC.  For empty SNACs this should be NULL.
 */
void
flap_connection_send_snac(OscarData *od, FlapConnection *conn, guint16 family, guint16 subtype, guint16 flags, aim_snacid_t snacid, ByteStream *data)
{
	FlapFrame *frame;
	guint32 length;
	gboolean enqueue = FALSE;
	struct rateclass *rateclass;

	length = data != NULL ? data->offset : 0;

	frame = flap_frame_new(od, 0x02, 10 + length);
	aim_putsnac(&frame->data, family, subtype, flags, snacid);

	if (length > 0)
	{
		byte_stream_rewind(data);
		byte_stream_putbs(&frame->data, data, length);
	}

	if (conn->queued_timeout != 0)
		enqueue = TRUE;
	else if ((rateclass = flap_connection_get_rateclass(conn, family, subtype)) != NULL)
	{
		struct timeval now;
		guint32 new_current;

		gettimeofday(&now, NULL);
		new_current = rateclass_get_new_current(conn, rateclass, &now);

		if (new_current < rateclass->alert + 100)
		{
			/* (Add 100ms padding to account for inaccuracies in the calculation) */
			enqueue = TRUE;
		}
		else
		{
			rateclass->current = new_current;
			rateclass->last.tv_sec = now.tv_sec;
			rateclass->last.tv_usec = now.tv_usec;
		}
	}

	if (enqueue)
	{
		/* We've been sending too fast, so delay this message */
		QueuedSnac *queued_snac;

		queued_snac = g_new(QueuedSnac, 1);
		queued_snac->family = family;
		queued_snac->subtype = subtype;
		queued_snac->frame = frame;
		g_queue_push_tail(conn->queued_snacs, queued_snac);

		if (conn->queued_timeout == 0)
			conn->queued_timeout = purple_timeout_add(500, flap_connection_send_queued, conn);

		return;
	}

	flap_connection_send(conn, frame);
}

/**
 * This sends an empty channel 4 FLAP.  This is sent to signify
 * that we're logging off.  This shouldn't really be necessary--
 * usually the AIM server will detect that the TCP connection has
 * been destroyed--but it's good practice.
 */
static void
flap_connection_send_close(OscarData *od, FlapConnection *conn)
{
	FlapFrame *frame;

	frame = flap_frame_new(od, 0x04, 0);
	flap_connection_send(conn, frame);
}

/**
 * This sends an empty channel 5 FLAP.  This is used as a keepalive
 * packet in FLAP connections.  WinAIM 4.x and higher send these
 * _every minute_ to keep the connection alive.
 */
void
flap_connection_send_keepalive(OscarData *od, FlapConnection *conn)
{
	FlapFrame *frame;

	frame = flap_frame_new(od, 0x05, 0);
	flap_connection_send(conn, frame);

	/* clean out SNACs over 60sec old */
	aim_cleansnacs(od, 60);
}

/**
 * Allocate a new empty connection structure.
 *
 * @param od The oscar session associated with this connection.
 * @param type Type of connection to create
 *
 * @return Returns the new connection structure.
 */
FlapConnection *
flap_connection_new(OscarData *od, int type)
{
	FlapConnection *conn;

	conn = g_new0(FlapConnection, 1);
	conn->od = od;
	conn->buffer_outgoing = purple_circ_buffer_new(0);
	conn->fd = -1;
	conn->subtype = -1;
	conn->type = type;
	conn->queued_snacs = g_queue_new();

	od->oscar_connections = g_slist_prepend(od->oscar_connections, conn);

	return conn;
}

/**
 * Close (but not free) a connection.
 *
 * This cancels any currently pending connection attempt,
 * closes any open fd and frees the auth cookie.
 *
 * @param conn The connection to close.
 */
void
flap_connection_close(OscarData *od, FlapConnection *conn)
{
	if (conn->connect_data != NULL)
	{
		purple_proxy_connect_cancel(conn->connect_data);
		conn->connect_data = NULL;
	}

	if (conn->connect_data != NULL)
	{
		if (conn->type == SNAC_FAMILY_CHAT)
		{
			oscar_chat_destroy(conn->new_conn_data);
			conn->connect_data = NULL;
		}
	}

	if (conn->fd >= 0)
	{
		if (conn->type == SNAC_FAMILY_LOCATE)
			flap_connection_send_close(od, conn);

		close(conn->fd);
		conn->fd = -1;
	}

	if (conn->watcher_incoming != 0)
	{
		purple_input_remove(conn->watcher_incoming);
		conn->watcher_incoming = 0;
	}

	if (conn->watcher_outgoing != 0)
	{
		purple_input_remove(conn->watcher_outgoing);
		conn->watcher_outgoing = 0;
	}

	g_free(conn->buffer_incoming.data.data);
	conn->buffer_incoming.data.data = NULL;

	purple_circ_buffer_destroy(conn->buffer_outgoing);
	conn->buffer_outgoing = NULL;
}

static void
flap_connection_destroy_rateclass(struct rateclass *rateclass)
{
	g_hash_table_destroy(rateclass->members);
	g_free(rateclass);
}

/**
 * Free a FlapFrame
 *
 * @param frame The frame to free.
 */
static void
flap_frame_destroy(FlapFrame *frame)
{
	g_free(frame->data.data);
	g_free(frame);
}

static gboolean
flap_connection_destroy_cb(gpointer data)
{
	FlapConnection *conn;
	OscarData *od;
	PurpleAccount *account;

	conn = data;
	od = conn->od;
	account = (PURPLE_CONNECTION_IS_VALID(od->gc) ? purple_connection_get_account(od->gc) : NULL);

	purple_debug_info("oscar", "Destroying oscar connection of "
			"type 0x%04hx\n", conn->type);

	od->oscar_connections = g_slist_remove(od->oscar_connections, conn);

	/*
	 * TODO: If we don't have a SNAC_FAMILY_LOCATE connection then
	 * we should try to request one instead of disconnecting.
	 */
	if (account && !account->disconnecting &&
		((od->oscar_connections == NULL) || (!flap_connection_getbytype(od, SNAC_FAMILY_LOCATE))))
	{
		/* No more FLAP connections!  Sign off this PurpleConnection! */
		gchar *tmp;
		if (conn->disconnect_reason == OSCAR_DISCONNECT_REMOTE_CLOSED)
			tmp = g_strdup(_("Server closed the connection."));
		else if (conn->disconnect_reason == OSCAR_DISCONNECT_LOST_CONNECTION)
			tmp = g_strdup_printf(_("Lost connection with server:\n%s"),
					conn->error_message);
		else if (conn->disconnect_reason == OSCAR_DISCONNECT_INVALID_DATA)
			tmp = g_strdup(_("Received invalid data on connection with server."));
		else if (conn->disconnect_reason == OSCAR_DISCONNECT_COULD_NOT_CONNECT)
			tmp = g_strdup_printf(_("Could not establish a connection with the server:\n%s"),
					conn->error_message);
		else
			/*
			 * We shouldn't print a message for some disconnect_reasons.
			 * Like OSCAR_DISCONNECT_LOCAL_CLOSED.
			 */
			tmp = NULL;

		if (tmp != NULL)
		{
			purple_connection_error(od->gc, tmp);
			g_free(tmp);
		}
	}

	flap_connection_close(od, conn);

	g_free(conn->error_message);
	g_free(conn->cookie);

	/*
	 * Free conn->internal, if necessary
	 */
	if (conn->type == SNAC_FAMILY_CHAT)
		flap_connection_destroy_chat(od, conn);

	g_slist_free(conn->groups);
	while (conn->rateclasses != NULL)
	{
		flap_connection_destroy_rateclass(conn->rateclasses->data);
		conn->rateclasses = g_slist_delete_link(conn->rateclasses, conn->rateclasses);
	}

	while (!g_queue_is_empty(conn->queued_snacs))
	{
		QueuedSnac *queued_snac;
		queued_snac = g_queue_pop_head(conn->queued_snacs);
		flap_frame_destroy(queued_snac->frame);
		g_free(queued_snac);
	}
	g_queue_free(conn->queued_snacs);
	if (conn->queued_timeout > 0)
		purple_timeout_remove(conn->queued_timeout);

	g_free(conn);

	return FALSE;
}

/**
 * See the comments for the parameters of
 * flap_connection_schedule_destroy().
 */
void
flap_connection_destroy(FlapConnection *conn, OscarDisconnectReason reason, const gchar *error_message)
{
	if (conn->destroy_timeout != 0)
		purple_timeout_remove(conn->destroy_timeout);
	conn->disconnect_reason = reason;
	g_free(conn->error_message);
	conn->error_message = g_strdup(error_message);
	flap_connection_destroy_cb(conn);
}

/**
 * Schedule Purple to destroy the given FlapConnection as soon as we
 * return control back to the program's main loop.  We must do this
 * if we want to destroy the connection but we are still using it
 * for some reason.
 *
 * @param reason The reason for the disconnection.
 * @param error_message A brief error message that gives more detail
 *        regarding the reason for the disconnecting.  This should
 *        be NULL for everything except OSCAR_DISCONNECT_LOST_CONNECTION,
 *        in which case it should contain the value of strerror(errno),
 *        and OSCAR_DISCONNECT_COULD_NOT_CONNECT, in which case it
 *        should contain the error_message passed back from the call
 *        to purple_proxy_connect().
 */
void
flap_connection_schedule_destroy(FlapConnection *conn, OscarDisconnectReason reason, const gchar *error_message)
{
	if (conn->destroy_timeout != 0)
		/* Already taken care of */
		return;

	purple_debug_info("oscar", "Scheduling destruction of FLAP "
			"connection of type 0x%04hx\n", conn->type);
	conn->disconnect_reason = reason;
	g_free(conn->error_message);
	conn->error_message = g_strdup(error_message);
	conn->destroy_timeout = purple_timeout_add(0, flap_connection_destroy_cb, conn);
}

/**
 * In OSCAR, every connection has a set of SNAC groups associated
 * with it.  These are the groups that you can send over this connection
 * without being guaranteed a "Not supported" SNAC error.
 *
 * The grand theory of things says that these associations transcend
 * what libfaim calls "connection types" (conn->type).  You can probably
 * see the elegance here, but since I want to revel in it for a bit, you
 * get to hear it all spelled out.
 *
 * So let us say that you have your core BOS connection running.  One