peer.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
*/

/*
 * Functions dealing with peer connections.  This includes the code
 * used to establish a peer connection for both Oscar File transfer
 * (OFT) and Oscar Direct Connect (ODC).  (ODC is also referred to
 * as DirectIM and IM Image.)
 */

#ifdef HAVE_CONFIG_H
#include  <config.h>
#endif

/* From the oscar PRPL */
#include "oscar.h"
#include "peer.h"

/* From Purple */
#include "conversation.h"
#include "ft.h"
#include "network.h"
#include "notify.h"
#include "request.h"
#include "util.h"

#ifndef _WIN32
#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h> /* for inet_ntoa */
#include <limits.h> /* for UINT_MAX */
#endif

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

/*
 * I really want to switch all our networking code to using IPv6 only,
 * but that really isn't a good idea at all.  Evan S. of Adium says
 * OS X sets all connections as "AF_INET6/PF_INET6," even if there is
 * nothing inherently IPv6 about them.  And I feel like Linux kernel
 * 2.6.5 is doing the same thing.  So we REALLY should accept
 * connections if they're showing up as IPv6.  Old OSes (Solaris?)
 * that might not have full IPv6 support yet will fail if we try
 * to use PF_INET6 but it isn't defined.  --Mark Doliner
 */
#ifndef PF_INET6
#define PF_INET6 PF_INET
#endif

PeerConnection *
peer_connection_find_by_type(OscarData *od, const char *sn, OscarCapability type)
{
	GSList *cur;
	PeerConnection *conn;

	for (cur = od->peer_connections; cur != NULL; cur = cur->next)
	{
		conn = cur->data;
		if ((conn->type == type) && !aim_sncmp(conn->sn, sn))
			return conn;
	}

	return NULL;
}

/**
 * @param cookie This must be exactly 8 characters.
 */
PeerConnection *
peer_connection_find_by_cookie(OscarData *od, const char *sn, const guchar *cookie)
{
	GSList *cur;
	PeerConnection *conn;

	for (cur = od->peer_connections; cur != NULL; cur = cur->next)
	{
		conn = cur->data;
		if (!memcmp(conn->cookie, cookie, 8) && !aim_sncmp(conn->sn, sn))
			return conn;
	}

	return NULL;
}

PeerConnection *
peer_connection_new(OscarData *od, OscarCapability type, const char *sn)
{
	PeerConnection *conn;
	PurpleAccount *account;

	account = purple_connection_get_account(od->gc);

	conn = g_new0(PeerConnection, 1);
	conn->od = od;
	conn->type = type;
	conn->sn = g_strdup(sn);
	conn->buffer_outgoing = purple_circ_buffer_new(0);
	conn->listenerfd = -1;
	conn->fd = -1;
	conn->lastactivity = time(NULL);
	conn->use_proxy |= purple_account_get_bool(account, "always_use_rv_proxy", FALSE);

	if (type == OSCAR_CAPABILITY_DIRECTIM)
		memcpy(conn->magic, "ODC2", 4);
	else if (type == OSCAR_CAPABILITY_SENDFILE)
		memcpy(conn->magic, "OFT2", 4);

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

	return conn;
}

static void
peer_connection_close(PeerConnection *conn)
{
	if (conn->type == OSCAR_CAPABILITY_DIRECTIM)
		peer_odc_close(conn);
	else if (conn->type == OSCAR_CAPABILITY_SENDFILE)
		peer_oft_close(conn);

	if (conn->verified_connect_data != NULL)
	{
		purple_proxy_connect_cancel(conn->verified_connect_data);
		conn->verified_connect_data = NULL;
	}

	if (conn->client_connect_data != NULL)
	{
		purple_proxy_connect_cancel(conn->client_connect_data);
		conn->client_connect_data = NULL;
	}

	if (conn->listen_data != NULL)
	{
		purple_network_listen_cancel(conn->listen_data);
		conn->listen_data = NULL;
	}

	if (conn->connect_timeout_timer != 0)
	{
		purple_timeout_remove(conn->connect_timeout_timer);
		conn->connect_timeout_timer = 0;
	}

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

	g_free(conn->buffer_incoming.data);
	conn->buffer_incoming.data = NULL;
	conn->buffer_incoming.len = 0;
	conn->buffer_incoming.offset = 0;

	purple_circ_buffer_destroy(conn->buffer_outgoing);
	conn->buffer_outgoing = purple_circ_buffer_new(0);

	conn->flags &= ~PEER_CONNECTION_FLAG_IS_INCOMING;
}

static gboolean
peer_connection_destroy_cb(gpointer data)
{
	PeerConnection *conn;

	conn = data;

	purple_request_close_with_handle(conn);

	peer_connection_close(conn);

	if (conn->checksum_data != NULL)
		peer_oft_checksum_destroy(conn->checksum_data);

	if (conn->xfer != NULL)
	{
		PurpleXferStatusType status;
		conn->xfer->data = NULL;
		status = purple_xfer_get_status(conn->xfer);
		if ((status != PURPLE_XFER_STATUS_DONE) &&
			(status != PURPLE_XFER_STATUS_CANCEL_LOCAL) &&
			(status != PURPLE_XFER_STATUS_CANCEL_REMOTE))
		{
			if ((conn->disconnect_reason == OSCAR_DISCONNECT_REMOTE_CLOSED) ||
				(conn->disconnect_reason == OSCAR_DISCONNECT_REMOTE_REFUSED))
				purple_xfer_cancel_remote(conn->xfer);
			else
				purple_xfer_cancel_local(conn->xfer);
		}
		purple_xfer_unref(conn->xfer);
		conn->xfer = NULL;
	}

	g_free(conn->sn);
	g_free(conn->error_message);
	g_free(conn->proxyip);
	g_free(conn->clientip);
	g_free(conn->verifiedip);
	g_free(conn->xferdata.name);
	purple_circ_buffer_destroy(conn->buffer_outgoing);

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

	g_free(conn);

	return FALSE;
}

void
peer_connection_destroy(PeerConnection *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);
	peer_connection_destroy_cb(conn);
}

void
peer_connection_schedule_destroy(PeerConnection *conn, OscarDisconnectReason reason, const gchar *error_message)
{
	if (conn->destroy_timeout != 0)
		/* Already taken care of */
		return;

	purple_debug_info("oscar", "Scheduling destruction of peer connection\n");
	conn->disconnect_reason = reason;
	g_free(conn->error_message);
	conn->error_message = g_strdup(error_message);
	conn->destroy_timeout = purple_timeout_add(0, peer_connection_destroy_cb, conn);
}

/*******************************************************************/
/* Begin code for receiving data on a peer connection                */
/*******************************************************************/

/**
 * This should be used to read ODC and OFT framing info.  It should
 * NOT be used to read the payload sent across the connection (IMs,
 * file data, etc), and it should NOT be used to read proxy negotiation
 * headers.
 *
 * Unlike flap_connection_recv_cb(), this only reads one frame at a
 * time.  This is done so that the watcher can be changed during the
 * handling of the frame.  If the watcher is changed then this
 * function will not read in any more data.  This happens when
 * reading the payload of a direct IM frame, or when we're
 * receiving a file from the remote user.  Once the data has been
 * read, the watcher will be switched back to this function to
 * continue reading the next frame.
 */
void
peer_connection_recv_cb(gpointer data, gint source, PurpleInputCondition cond)
{
	PeerConnection *conn;
	ssize_t read;

	conn = data;

	/* Start reading a new ODC/OFT frame */
	if (conn->buffer_incoming.data == NULL)
	{
		/* Read the first 6 bytes (magic string and frame length) */
		read = recv(conn->fd, conn->header + conn->header_received,
				6 - conn->header_received, 0);

		/* Check if the remote user closed the connection */
		if (read == 0)
		{
			peer_connection_destroy(conn, OSCAR_DISCONNECT_REMOTE_CLOSED, NULL);
			return;
		}

		/* If there was an error then close the connection */
		if (read < 0)
		{
			if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
				/* No worries */
				return;

			peer_connection_destroy(conn,
					OSCAR_DISCONNECT_LOST_CONNECTION, strerror(errno));
			return;
		}

		conn->lastactivity = time(NULL);

		/* If we don't even have the first 6 bytes then do nothing */
		conn->header_received += read;
		if (conn->header_received < 6)
			return;

		/* All ODC/OFT frames must start with a magic string */
		if (memcmp(conn->magic, conn->header, 4))
		{
			purple_debug_warning("oscar", "Expecting magic string to "
				"be %c%c%c%c but received magic string %c%c%c%c.  "
				"Closing connection.\n",
				conn->magic[0], conn->magic[1], conn->magic[2],
				conn->magic[3], conn->header[0], conn->header[1],
				conn->header[2], conn->header[3]);
			peer_connection_destroy(conn, OSCAR_DISCONNECT_INVALID_DATA, NULL);
			return;
		}

		/* Initialize a new temporary ByteStream for incoming data */
		conn->buffer_incoming.len = aimutil_get16(&conn->header[4]) - 6;
		conn->buffer_incoming.data = g_new(guint8, conn->buffer_incoming.len);
		conn->buffer_incoming.offset = 0;
	}

	/* Read data into the temporary buffer until it is complete */
	read = recv(conn->fd,
				&conn->buffer_incoming.data[conn->buffer_incoming.offset],
				conn->buffer_incoming.len - conn->buffer_incoming.offset,
				0);

	/* Check if the remote user closed the connection */
	if (read == 0)
	{
		peer_connection_destroy(conn, OSCAR_DISCONNECT_REMOTE_CLOSED, NULL);
		return;
	}