From: Paul Fertser <fercerpav@gmail.com>
Date: Tue, 20 Jan 2009 22:44:39 +0000 (+0300)
Subject: Implement proper channel allocation and dealloction
X-Git-Tag: 0.9.3~4
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=b8949ff6ef8f7c5d2e37170e4005d2dd968d2b77;p=gsm0710muxd.git

Implement proper channel allocation and dealloction

With this patch the muxer will allocate channels in a clean way, it will
not return a pts until the modem is really ready to operate on this
channel.  It will also retry the command several times until the channel is
allocated.

Channel deallocation is also greatly improved, now we send a correct code to
close a channel and will repeat several times if the packet somehow (e.g.
modem was in power-saving state) lost.
---

diff --git a/src/gsm0710muxd.c b/src/gsm0710muxd.c
index cb8df03..ecbf608 100644
--- a/src/gsm0710muxd.c
+++ b/src/gsm0710muxd.c
@@ -148,6 +148,7 @@ typedef struct Channel
 	char* devicename;
 	int fd;
 	int opened;
+	int frames_allowed;
 	unsigned char v24_signals;
 	char* ptsname;
 	char* origin;
@@ -291,6 +292,12 @@ static int baud_rate_index(
 	return -1;
 }
 
+gboolean glib_returnfalse(
+       gpointer data)
+{
+       return FALSE;
+}
+
 /**
  * Calculates frame check sequence from given characters.
  *
@@ -525,6 +532,36 @@ static int handle_channel_data(
 
 static int logical_channel_close(Channel* channel)
 {
+	guint timeout_id;
+	GSource *timeout_source;
+	int write_retries;
+
+	LOG(LOG_DEBUG, "Enter");
+	if (channel->opened)
+	{
+		LOG(LOG_INFO, "Logical channel %d for %s closing", channel->id, channel->origin);
+		for (write_retries=0; write_retries<GSM0710_WRITE_RETRIES; write_retries++)
+		{
+			if (cmux_mode)
+				write_frame(channel->id, NULL, 0, GSM0710_TYPE_DISC | GSM0710_PF);
+			else
+				write_frame(channel->id, close_channel_cmd, 2, GSM0710_TYPE_UIH);
+			timeout_id = g_timeout_add_seconds(3, glib_returnfalse, NULL);
+			timeout_source = g_main_context_find_source_by_id(NULL, timeout_id);
+			do
+			{
+				LOG(LOG_DEBUG, "g_main_context_iteration");
+				g_main_context_iteration(NULL, TRUE);
+			}
+			while (channel->opened && !g_source_is_destroyed(timeout_source));
+			if (!channel->opened)
+				break;
+		} 
+		/* No need to explicitly destroy this source */
+		if (channel->opened)
+			LOG(LOG_WARNING, "Unable to properly close a channel");
+	}
+
 	if (channel->g_source >= 0)
 		g_source_remove(channel->g_source);
 	channel->g_source = -1;
@@ -541,6 +578,7 @@ static int logical_channel_close(Channel* channel)
 		free(channel->origin);
 	channel->origin = NULL;
 	channel->opened = 0;
+	channel->frames_allowed = 0;
 	channel->v24_signals = 0;
 	channel->remaining = 0;
 	return 0;
@@ -555,6 +593,7 @@ static int logical_channel_init(Channel* channel, int id)
 	channel->ptsname = NULL;
 	channel->tmp = NULL;
 	channel->origin = NULL;
+	channel->opened = 0;
 	return logical_channel_close(channel);
 }
 
@@ -595,21 +634,11 @@ gboolean pseudo_device_read(GIOChannel *source, GIOCondition condition, gpointer
 			return TRUE;
 		}
 		// dropped connection
-		if (cmux_mode)
-			write_frame(channel->id, NULL, 0, GSM0710_CONTROL_CLD | GSM0710_CR);
-		else
-			write_frame(channel->id, close_channel_cmd, 2, GSM0710_TYPE_UIH);
 		logical_channel_close(channel);
-		LOG(LOG_INFO, "Logical channel %d for %s closed", channel->id, channel->origin);
 	}
 	else if (condition == G_IO_HUP)
 	{
-		if (cmux_mode)
-			write_frame(channel->id, NULL, 0, GSM0710_CONTROL_CLD | GSM0710_CR);
-		else
-			write_frame(channel->id, close_channel_cmd, 2, GSM0710_TYPE_UIH);
 		logical_channel_close(channel);
-		LOG(LOG_INFO, "Logical channel %d for %s closed", channel->id, channel->origin);
 	}
 	LOG(LOG_DEBUG, "Leave");
 	return FALSE;
@@ -666,6 +695,9 @@ static gboolean c_alloc_channel(const char* origin, const char** name)
 {
 	LOG(LOG_DEBUG, "Enter");
 	int i;
+	guint timeout_id;
+	GSource *timeout_source;
+	int write_retries;
 	if (serial.state == MUX_STATE_MUXING)
 		for (i=1;i<GSM0710_MAX_CHANNELS;i++)
 			if (channellist[i].fd < 0) // is this channel free?
@@ -693,10 +725,30 @@ static gboolean c_alloc_channel(const char* origin, const char** name)
 				g_io_channel_set_encoding(channellist[i].g_channel, NULL, NULL );
 				g_io_channel_set_buffer_size( channellist[i].g_channel, PTY_GLIB_BUFFER_SIZE );
 				channellist[i].g_source = g_io_add_watch(channellist[i].g_channel, G_IO_IN | G_IO_HUP, pseudo_device_read, channellist+i);
-				write_frame(i, NULL, 0, GSM0710_TYPE_SABM | GSM0710_PF);
 				LOG(LOG_INFO, "Connecting %s to virtual channel %d for %s on %s",
 					channellist[i].ptsname, channellist[i].id, channellist[i].origin, serial.devicename);
 				*name = strdup(channellist[i].ptsname);
+				for (write_retries=0; write_retries<GSM0710_WRITE_RETRIES; write_retries++)
+				{
+					write_frame(i, NULL, 0, GSM0710_TYPE_SABM | GSM0710_PF);
+					timeout_id = g_timeout_add_seconds(3, glib_returnfalse, NULL);
+					timeout_source = g_main_context_find_source_by_id(NULL, timeout_id);
+					do
+					{
+						LOG(LOG_DEBUG, "g_main_context_iteration");
+						g_main_context_iteration(NULL, TRUE);
+					}
+					while (!channellist[i].frames_allowed && !g_source_is_destroyed(timeout_source));
+					if (channellist[i].opened)
+						break;
+				} 
+				/* No need to explicitly destroy this source */
+				if (!channellist[i].frames_allowed)
+				{
+					LOG(LOG_INFO, "Unable to open the new channel %d", i);
+					logical_channel_close(&channellist[i]);
+					return FALSE;
+				}
 				return TRUE;
 			}
 	LOG(LOG_WARNING, "not muxing or no free channel found");
@@ -1291,6 +1343,7 @@ static int handle_command(
 					{
 //op.arg |= USSP_CTS;
 						LOG(LOG_DEBUG, "Frames allowed");
+						channellist[channel].frames_allowed = 1;
 					}
 					if ((signals & GSM0710_SIGNAL_RTC) == GSM0710_SIGNAL_RTC)
 					{
@@ -1403,9 +1456,9 @@ int extract_frames(
 				LOG(LOG_DEBUG, "Frame is UA");
 				if (channellist[frame->channel].opened)
 				{
-					SYSCHECK(logical_channel_close(channellist+frame->channel));
 					LOG(LOG_INFO, "Logical channel %d for %s closed",
 						frame->channel, channellist[frame->channel].origin);
+					channellist[frame->channel].opened = 0;
 				}
 				else
 				{
@@ -1721,11 +1774,6 @@ static int close_devices()
 			if (channellist[i].opened)
 			{
 				LOG(LOG_INFO, "Closing down the logical channel %d", i);
-				if (cmux_mode)
-					write_frame(i, NULL, 0, GSM0710_CONTROL_CLD | GSM0710_CR);
-//multiplexer close down command doesn't work with benqM22a module, use: write_frame(0, NULL, 0, GSM0710_TYPE_DISC | GSM0710_PF);
-				else
-					write_frame(i, close_channel_cmd, 2, GSM0710_TYPE_UIH);
 				SYSCHECK(logical_channel_close(channellist+i));
 			}
 			LOG(LOG_INFO, "Logical channel %d closed", channellist[i].id);
@@ -1972,7 +2020,8 @@ int main(
 	g_main_loop_run(main_loop); // will/may be terminated in signal_treatment
 	g_main_loop_unref(main_loop);
 //finalize everything
-	SYSCHECK(close_devices());
+//	Don't bother with closing devices, mainloop is not running anymore
+//	SYSCHECK(close_devices());
 	free(serial.adv_frame_buf);
 	gsm0710_buffer_destroy(serial.in_buf);
 	LOG(LOG_INFO, "Received %ld frames and dropped %ld received frames during the mux-mode",