Add smdi support for asterisk (see doc/smdi.txt for config info) (#5945)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@9423 65c4cc65-6c06-0410-ace0-fbb531ad65f3

2 files changed, 801 insertions, 0 deletions

diff --git a/res/Makefile b/res/Makefile
index 5b127713d..0ade18337 100644
--- a/res/Makefile
+++ b/res/Makefile
@@ -64,6 +64,13 @@ else
 CFLAGS+=-DOPENSSL_NO_KRB5 -fPIC
 endif
 
+#
+# Asterisk SMDI integration
+#
+ifeq (${WITH_SMDI},1)
+MODS+=res_smdi.so
+endif
+
 all: depend $(MODS)
 
 install: all
diff --git a/res/res_smdi.c b/res/res_smdi.c
new file mode 100644
index 000000000..7c83478a2
--- /dev/null
+++ b/res/res_smdi.c
@@ -0,0 +1,794 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * SMDI support for Asterisk.
+ * 
+ * Copyright (C) 2005, Digium, Inc.
+ *
+ * Matthew A. Nicholson <mnicholson@digium.com>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <termios.h>
+#include <sys/time.h>
+#include <time.h>
+#include <ctype.h>
+#include "asterisk/module.h"
+#include "asterisk/lock.h"
+#include "asterisk/utils.h"
+#include "asterisk/smdi.h"
+#include "asterisk/config.h"
+#include "asterisk/astobj.h"
+#include "asterisk/io.h"
+#include "asterisk/logger.h"
+#include "asterisk/utils.h"
+#include "asterisk/options.h"
+
+/*!
+ * \file
+ * \brief SMDI support for Asterisk.
+ * \author Matthew A. Nicholson <mnicholson@digium.com>
+ */
+
+/* Message expiry time in milliseconds */
+#define SMDI_MSG_EXPIRY_TIME	30000 /* 30 seconds */
+
+static const char tdesc[] = "Asterisk Simplified Message Desk Interface (SMDI) Module";
+static const char config_file[] = "smdi.conf";
+
+static void ast_smdi_md_message_push(struct ast_smdi_interface *iface, struct ast_smdi_md_message *msg);
+static void ast_smdi_mwi_message_push(struct ast_smdi_interface *iface, struct ast_smdi_mwi_message *msg);
+
+static void *smdi_read(void *iface_p);
+static int smdi_load(int reload);
+
+/* Use count stuff */
+
+AST_MUTEX_DEFINE_STATIC(localuser_lock);
+static int localusecnt = 0;
+
+/*! \brief SMDI interface container. */
+struct ast_smdi_interface_container {
+	ASTOBJ_CONTAINER_COMPONENTS(struct ast_smdi_interface);
+} smdi_ifaces;
+
+/*! 
+ * \internal
+ * \brief Push an SMDI message to the back of an interface's message queue.
+ * \param iface a pointer to the interface to use.
+ * \param md_msg a pointer to the message to use.
+ */
+static void ast_smdi_md_message_push(struct ast_smdi_interface *iface, struct ast_smdi_md_message *md_msg)
+{
+	ASTOBJ_CONTAINER_LINK_END(&iface->md_q, md_msg);
+}
+
+/*!
+ * \internal
+ * \brief Push an SMDI message to the back of an interface's message queue.
+ * \param iface a pointer to the interface to use.
+ * \param mwi_msg a pointer to the message to use.
+ */
+static void ast_smdi_mwi_message_push(struct ast_smdi_interface *iface, struct ast_smdi_mwi_message *mwi_msg)
+{
+	ASTOBJ_CONTAINER_LINK_END(&iface->mwi_q, mwi_msg);
+}
+
+/*!
+ * \brief Set the MWI indicator for a mailbox.
+ * \param iface the interface to use.
+ * \param mailbox the mailbox to use.
+ */
+extern int ast_smdi_mwi_set(struct ast_smdi_interface *iface, const char *mailbox)
+{
+	FILE *file;
+	int i;
+	
+	file = fopen(iface->name, "w");
+	if(!file) {
+		ast_log(LOG_ERROR, "Error opening SMDI interface %s (%s) for writing\n", iface->name, strerror(errno));
+		return 1;
+	}	
+
+	ASTOBJ_WRLOCK(iface);
+
+	fprintf(file, "OP:MWI ");
+
+	for(i = 0; i < iface->msdstrip; i++)
+	   fprintf(file, "0");
+
+	fprintf(file, "%s!\x04", mailbox);
+	fclose(file);
+
+	ASTOBJ_UNLOCK(iface);
+	ast_log(LOG_DEBUG, "Sent MWI set message for %s on %s\n", mailbox, iface->name);
+	return 0;
+}
+
+/*! 
+ * \brief Unset the MWI indicator for a mailbox.
+ * \param iface the interface to use.
+ * \param mailbox the mailbox to use.
+ */
+extern int ast_smdi_mwi_unset(struct ast_smdi_interface *iface, const char *mailbox)
+{
+	FILE *file;
+	int i;
+	
+	file = fopen(iface->name, "w");
+	if(!file) {
+		ast_log(LOG_ERROR, "Error opening SMDI interface %s (%s) for writing\n", iface->name, strerror(errno));
+		return 1;
+	}	
+
+	ASTOBJ_WRLOCK(iface);
+
+	fprintf(file, "RMV:MWI ");
+
+	for(i = 0; i < iface->msdstrip; i++)
+	   fprintf(file, "0");
+
+	fprintf(file, "%s!\x04", mailbox);
+	fclose(file);
+
+	ASTOBJ_UNLOCK(iface);
+	ast_log(LOG_DEBUG, "Sent MWI unset message for %s on %s", mailbox, iface->name);
+	return 0;
+}
+
+/*!
+ * \brief Put an SMDI message back in the front of the queue.
+ * \param iface a pointer to the interface to use.
+ * \param msg a pointer to the message to use.
+ *
+ * This function puts a message back in the front of the specified queue.  It
+ * should be used if a message was popped but is not going to be processed for
+ * some reason, and the message needs to be returned to the queue.
+ */
+extern void ast_smdi_md_message_putback(struct ast_smdi_interface *iface, struct ast_smdi_md_message *md_msg)
+{
+	ASTOBJ_CONTAINER_LINK_START(&iface->md_q, md_msg);
+}
+
+/*!
+ * \brief Put an SMDI message back in the front of the queue.
+ * \param iface a pointer to the interface to use.
+ * \param msg a pointer to the message to use.
+ *
+ * This function puts a message back in the front of the specified queue.  It
+ * should be used if a message was popped but is not going to be processed for
+ * some reason, and the message needs to be returned to the queue.
+ */
+extern void ast_smdi_mwi_message_putback(struct ast_smdi_interface *iface, struct ast_smdi_mwi_message *mwi_msg)
+{
+	ASTOBJ_CONTAINER_LINK_START(&iface->mwi_q, mwi_msg);
+}
+
+/*! 
+ * \brief Get the next SMDI message from the queue.
+ * \param iface a pointer to the interface to use.
+ *
+ * This function pulls the first unexpired message from the SMDI message queue
+ * on the specified interface.  It will purge all expired SMDI messages before
+ * returning.
+ *
+ * \return the next SMDI message, or NULL if there were no pending messages.
+ */
+extern struct ast_smdi_md_message *ast_smdi_md_message_pop(struct ast_smdi_interface *iface)
+{
+	struct ast_smdi_md_message *md_msg = ASTOBJ_CONTAINER_UNLINK_START(&iface->md_q);
+	struct timeval now;
+	long elapsed = 0;
+
+	/* purge old messages */
+	gettimeofday(&now, NULL);
+	while(md_msg)
+	{
+		/* calculate the elapsed time since this message was recieved ( in milliseconds) */
+		elapsed = (now.tv_sec - md_msg->timestamp.tv_sec) * 1000;
+		elapsed += (now.tv_usec - md_msg->timestamp.tv_usec) / 1000;
+
+		if(elapsed > iface->msg_expiry)
+		{ /* found an expired message */
+			ASTOBJ_UNREF(md_msg,ast_smdi_md_message_destroy);
+			ast_log(LOG_NOTICE, "Purged expired message from %s SMDI MD message queue.  Message was %ld milliseconds too old.", iface->name, elapsed - iface->msg_expiry);
+			md_msg = ASTOBJ_CONTAINER_UNLINK_START(&iface->md_q);
+		}
+		else /* good message, return it */
+		{
+			break;
+		}
+	}
+
+	return md_msg;
+}
+
+/*!
+ * \brief Get the next SMDI message from the queue.
+ * \param iface a pointer to the interface to use.
+ * \param timeout the time to wait before returning in milliseconds.
+ *
+ * This function pulls a message from the SMDI message queue on the specified
+ * interface.  If no message is available this function will wait the specified
+ * amount of time before returning.
+ *
+ * \return the next SMDI message, or NULL if there were no pending messages and
+ * the timeout has expired.
+ */
+extern struct ast_smdi_md_message *ast_smdi_md_message_wait(struct ast_smdi_interface *iface, int timeout)
+{
+	struct timeval start, end;
+	long diff = 0;
+	struct ast_smdi_md_message *msg;
+
+	gettimeofday(&start, NULL);
+	while(diff < timeout) {
+
+		if((msg = ast_smdi_md_message_pop(iface)))
+			return msg;
+
+		/* check timeout */
+		gettimeofday(&end, NULL);
+		diff = (end.tv_sec - start.tv_sec) * 1000;
+		diff += (end.tv_usec - start.tv_usec) / 1000;
+	}
+	return (ast_smdi_md_message_pop(iface));
+}
+
+/*!
+ * \brief Get the next SMDI message from the queue.
+ * \param iface a pointer to the interface to use.
+ *
+ * This function pulls the first unexpired message from the SMDI message queue
+ * on the specified interface.  It will purge all expired SMDI messages before
+ * returning.
+ *
+ * \return the next SMDI message, or NULL if there were no pending messages.
+ */
+extern struct ast_smdi_mwi_message *ast_smdi_mwi_message_pop(struct ast_smdi_interface *iface)
+{
+	struct ast_smdi_mwi_message *mwi_msg = ASTOBJ_CONTAINER_UNLINK_START(&iface->mwi_q);
+	struct timeval now;
+	long elapsed = 0;
+
+	/* purge old messages */
+	gettimeofday(&now, NULL);
+	while(mwi_msg)
+	{
+		/* calculate the elapsed time since this message was recieved ( in milliseconds) */
+		elapsed = (now.tv_sec - mwi_msg->timestamp.tv_sec) * 1000;
+		elapsed += (now.tv_usec - mwi_msg->timestamp.tv_usec) / 1000;
+
+		if(elapsed > iface->msg_expiry)
+		{ /* found an expired message */
+			ASTOBJ_UNREF(mwi_msg,ast_smdi_mwi_message_destroy);
+			ast_log(LOG_NOTICE, "Purged expired message from %s SMDI MWI message queue.  Message was %ld milliseconds too old.", iface->name, elapsed - iface->msg_expiry);
+			mwi_msg = ASTOBJ_CONTAINER_UNLINK_START(&iface->mwi_q);
+		}
+		else /* good message, return it */
+		{
+			break;
+		}
+	}
+
+	return mwi_msg;
+	return (ASTOBJ_CONTAINER_UNLINK_START(&iface->mwi_q));
+}
+
+/*!
+ * \brief Get the next SMDI message from the queue.
+ * \param iface a pointer to the interface to use.
+ * \param timeout the time to wait before returning in milliseconds.
+ *
+ * This function pulls a message from the SMDI message queue on the specified
+ * interface.  If no message is available this function will wait the specified
+ * amount of time before returning.
+ *
+ * \return the next SMDI message, or NULL if there were no pending messages and
+ * the timeout has expired.
+ */
+extern struct ast_smdi_mwi_message *ast_smdi_mwi_message_wait(struct ast_smdi_interface *iface, int timeout)
+{
+	struct timeval start, end;
+	long diff = 0;
+	struct ast_smdi_mwi_message *msg;
+
+	gettimeofday(&start, NULL);
+	while(diff < timeout) {
+
+		if((msg = ast_smdi_mwi_message_pop(iface)))
+			return msg;
+
+		/* check timeout */
+		gettimeofday(&end, NULL);
+		diff = (end.tv_sec - start.tv_sec) * 1000;
+		diff += (end.tv_usec - start.tv_usec) / 1000;
+	}
+	return (ast_smdi_mwi_message_pop(iface));
+}
+
+/*!
+ * \brief Find an SMDI interface with the specified name.
+ * \param iface_name the name/port of the interface to search for.
+ *
+ * \return a pointer to the interface located or NULL if none was found.  This
+ * actually returns an ASTOBJ reference and should be released using
+ * #ASTOBJ_UNREF(iface, ast_smdi_interface_destroy).
+ */
+extern struct ast_smdi_interface *ast_smdi_interface_find(const char *iface_name)
+{
+	return (ASTOBJ_CONTAINER_FIND(&smdi_ifaces,iface_name));
+}
+
+/*! \brief Read an SMDI message.
+ *
+ * \param iface the SMDI interface to read from.
+ *
+ * This function loops and reads from and SMDI interface.  It must be stopped
+ * using pthread_cancel().
+ */
+static void *smdi_read(void *iface_p)
+{
+	struct ast_smdi_interface *iface = iface_p;
+	struct ast_smdi_md_message *md_msg;
+	struct ast_smdi_mwi_message *mwi_msg;
+	char c = '\0';
+	char *cp = NULL;
+	int i;
+	int start = 0;
+		
+	/* read an smdi message */
+	while((c = fgetc(iface->file))) {
+
+		/* check if this is the start of a message */
+		if(!start)
+		{
+			if(c == 'M')
+				start = 1;
+		}
+		else /* Determine if this is a MD or MWI message */
+		{
+			if(c == 'D') { /* MD message */
+				start = 0;
+
+				md_msg = malloc(sizeof(struct ast_smdi_md_message));
+				if(!md_msg) {
+					ast_log(LOG_ERROR, "Error allocating memory for ast_smdi_md_message.  Stopping listner thread.\n");
+					ASTOBJ_UNREF(iface,ast_smdi_interface_destroy);
+					return NULL;
+				}
+				memset(md_msg, 0, sizeof(struct ast_smdi_md_message));
+				
+				ASTOBJ_INIT(md_msg);
+
+				/* read the message desk number */
+				for(i = 0; i < SMDI_MESG_DESK_NUM_LEN; i++) {
+					md_msg->mesg_desk_num[i] = fgetc(iface->file);
+				}
+				md_msg->mesg_desk_num[SMDI_MESG_DESK_NUM_LEN] = '\0';
+
+				/* read the message desk terminal number */
+				for(i = 0; i < SMDI_MESG_DESK_TERM_LEN; i++) {
+					md_msg->mesg_desk_term[i] = fgetc(iface->file);
+				}
+				md_msg->mesg_desk_term[SMDI_MESG_DESK_TERM_LEN] = '\0';
+
+				/* read the message type */
+				md_msg->type = fgetc(iface->file);
+			   
+				/* read the forwarding station number (may be blank) */
+				cp = &md_msg->fwd_st[0];
+				for(i = 0; i < SMDI_MAX_STATION_NUM_LEN + 1; i++) {
+					if((c = fgetc(iface->file)) == ' ') {
+						*cp = '\0';
+						break;
+					}
+
+					/* store c in md_msg->fwd_st */
+					if( i >= iface->msdstrip) {
+						*cp = c;
+						cp++;
+					}
+				}
+				/* make sure the value is null terminated, even if this truncates it */
+				md_msg->fwd_st[SMDI_MAX_STATION_NUM_LEN] = '\0';
+				cp = NULL;
+				
+				/* read the calling station number (may be blank) */
+				cp = &md_msg->calling_st[0];
+				for(i = 0; i < SMDI_MAX_STATION_NUM_LEN + 1; i++) {
+					if(!isdigit( (c = fgetc(iface->file)) )) {
+						*cp = '\0';
+						break;
+					}
+
+					/* store c in md_msg->calling_st */
+					if( i >= iface->msdstrip) {
+						*cp = c;
+						cp++;
+					}
+				}
+				/* make sure the value is null terminated, even if this truncates it */
+				md_msg->calling_st[SMDI_MAX_STATION_NUM_LEN] = '\0';
+				cp = NULL;
+
+				/* add the message to the message queue */
+				gettimeofday(&md_msg->timestamp, NULL);
+				ast_smdi_md_message_push(iface, md_msg);
+				ast_log(LOG_DEBUG, "Recieved SMDI MD message on %s\n", iface->name);
+				
+				ASTOBJ_UNREF(md_msg, ast_smdi_md_message_destroy);
+
+			} else if(c == 'W') { /* MWI message */
+				start = 0;
+
+				mwi_msg = malloc(sizeof(struct ast_smdi_mwi_message));
+				if(!mwi_msg) {
+					ast_log(LOG_ERROR, "Error allocating memory for ast_smdi_mwi_message.  Stopping listner thread.\n");
+					ASTOBJ_UNREF(iface,ast_smdi_interface_destroy);
+					return NULL;
+				}
+				memset(mwi_msg, 0, sizeof(struct ast_smdi_mwi_message));
+				
+				ASTOBJ_INIT(mwi_msg);
+
+				/* discard the 'I' (from 'MWI') */
+				fgetc(iface->file);
+				
+				/* read the forwarding station number (may be blank) */
+				cp = &mwi_msg->fwd_st[0];
+				for(i = 0; i < SMDI_MAX_STATION_NUM_LEN + 1; i++) {
+					if((c = fgetc(iface->file)) == ' ') {
+						*cp = '\0';
+						break;
+					}
+
+					/* store c in md_msg->fwd_st */
+					if( i >= iface->msdstrip) {
+						*cp = c;
+						cp++;
+					}
+				}
+				/* make sure the station number is null terminated, even if this will truncate it */
+				mwi_msg->fwd_st[SMDI_MAX_STATION_NUM_LEN] = '\0';
+				cp = NULL;
+				
+				/* read the mwi failure cause */
+				for(i = 0; i < SMDI_MWI_FAIL_CAUSE_LEN; i++) {
+					mwi_msg->cause[i] = fgetc(iface->file);
+				}
+				mwi_msg->cause[SMDI_MWI_FAIL_CAUSE_LEN] = '\0';
+
+				/* add the message to the message queue */
+				gettimeofday(&mwi_msg->timestamp, NULL);
+				ast_smdi_mwi_message_push(iface, mwi_msg);
+				ast_log(LOG_DEBUG, "Recieved SMDI MWI message on %s\n", iface->name);
+				
+				ASTOBJ_UNREF(mwi_msg, ast_smdi_mwi_message_destroy);
+			} else {
+				ast_log(LOG_ERROR, "Unknown SMDI message type recieved on %s (M%c).\n", iface->name, c);
+				start = 0;
+			}
+		}
+	}
+
+	ast_log(LOG_ERROR, "Error reading from SMDI interface %s, stopping listener thread\n", iface->name);
+	ASTOBJ_UNREF(iface,ast_smdi_interface_destroy);
+	return NULL;
+}
+
+/*! \brief ast_smdi_md_message destructor. */
+void ast_smdi_md_message_destroy(struct ast_smdi_md_message *msg)
+{
+	free(msg);
+}
+
+/*! \brief ast_smdi_mwi_message destructor. */
+void ast_smdi_mwi_message_destroy(struct ast_smdi_mwi_message *msg)
+{
+	free(msg);
+}
+
+/*! \brief ast_smdi_interface destructor. */
+void ast_smdi_interface_destroy(struct ast_smdi_interface *iface)
+{
+	if(iface->thread != AST_PTHREADT_NULL && iface->thread != AST_PTHREADT_STOP) {
+		pthread_cancel(iface->thread);
+		pthread_join(iface->thread, NULL);
+	}
+	
+	iface->thread = AST_PTHREADT_STOP;
+	
+	if(iface->file) 
+		fclose(iface->file);
+	
+	ASTOBJ_CONTAINER_DESTROYALL(&iface->md_q, ast_smdi_md_message_destroy);
+	ASTOBJ_CONTAINER_DESTROYALL(&iface->mwi_q, ast_smdi_mwi_message_destroy);
+	ASTOBJ_CONTAINER_DESTROY(&iface->md_q);
+	ASTOBJ_CONTAINER_DESTROY(&iface->mwi_q);
+	free(iface);
+
+	ast_mutex_lock(&localuser_lock);
+	localusecnt--;
+	ast_mutex_unlock(&localuser_lock);
+	ast_update_use_count();
+}
+
+/*!
+ * \internal
+ * \brief Load and reload SMDI configuration.
+ * \param reload this should be 1 if we are reloading and 0 if not.
+ *
+ * This function loads/reloads the SMDI configuration and starts and stops
+ * interfaces accordingly.
+ *
+ * \return zero on success, -1 on failure, and 1 if no smdi interfaces were started.
+ */
+static int smdi_load(int reload)
+{
+	struct ast_config *conf;
+	struct ast_variable *v;
+	struct ast_smdi_interface *iface = NULL;
+	int res = 0;
+
+	/* Config options */
+	speed_t baud_rate = B9600;     /* 9600 baud rate */
+	tcflag_t paritybit = PARENB;   /* even parity checking */
+	tcflag_t charsize = CS7;       /* seven bit characters */
+	int stopbits = 0;              /* One stop bit */
+	
+	int msdstrip = 0;              /* strip zero digits */
+	long msg_expiry = SMDI_MSG_EXPIRY_TIME;
+	
+	conf = ast_config_load(config_file);
+
+	if(!conf) {
+		ast_log(LOG_ERROR, "Unable to load config %s\n", config_file);
+		return -1;
+	}
+
+	/* Mark all interfaces that we are listening on.  We will unmark them
+	 * as we find them in the config file, this way we know any interfaces
+	 * still marked after we have finished parsing the config file should
+	 * be stopped.
+	 */
+	if(reload)
+		ASTOBJ_CONTAINER_MARKALL(&smdi_ifaces);
+
+	v = ast_variable_browse(conf, "interfaces");
+	while(v) {
+		if(!strcasecmp(v->name, "baudrate")) {
+			if(!strcasecmp(v->value, "9600")) {
+				baud_rate = B9600;
+			} else if(!strcasecmp(v->value, "4800")) {
+				baud_rate = B4800;
+			} else if(!strcasecmp(v->value, "2400")) {
+				baud_rate = B2400;
+			} else if(!strcasecmp(v->value, "1200")) {
+				baud_rate = B1200;
+			} else {
+				ast_log(LOG_NOTICE, "Invalid baud rate '%s' specified in %s (line %d), using default\n", v->value, config_file, v->lineno);
+				baud_rate = B9600;
+			}
+		} else if(!strcasecmp(v->name, "msdstrip")) {
+			if(!sscanf(v->value, "%d", &msdstrip)) {
+				ast_log(LOG_NOTICE, "Invalid msdstrip value in %s (line %d), using default\n", config_file, v->lineno);
+				msdstrip = 0;
+			} else if(0 > msdstrip || msdstrip > 9) {
+				ast_log(LOG_NOTICE, "Invalid msdstrip value in %s (line %d), using default\n", config_file, v->lineno);
+				msdstrip = 0;
+			}
+		} else if(!strcasecmp(v->name, "msgexpirytime")) {
+			if(!sscanf(v->value, "%ld", &msg_expiry)) {
+				ast_log(LOG_NOTICE, "Invalid msgexpirytime value in %s (line %d), using default\n", config_file, v->lineno);
+				msg_expiry = SMDI_MSG_EXPIRY_TIME;
+			}
+		} else if(!strcasecmp(v->name, "paritybit")) {
+			if(!strcasecmp(v->value, "even")) {
+				paritybit = PARENB;
+			} else if(!strcasecmp(v->value, "odd")) {
+				paritybit = PARENB | PARODD;
+			} else if(!strcasecmp(v->value, "none")) {
+				paritybit = ~PARENB;
+			} else {
+				ast_log(LOG_NOTICE, "Invalid parity bit setting in %s (line %d), using default\n", config_file, v->lineno);
+				paritybit = PARENB;
+			}
+		} else if(!strcasecmp(v->name, "charsize")) {
+			if(!strcasecmp(v->value, "7")) {
+				charsize = CS7;
+			} else if(!strcasecmp(v->value, "8")) {
+				charsize = CS8;
+			} else {
+				ast_log(LOG_NOTICE, "Invalid character size setting in %s (line %d), using default\n", config_file, v->lineno);
+				charsize = CS7;
+			}
+		} else if(!strcasecmp(v->name, "twostopbits")) {
+			stopbits = ast_true(v->name);
+		} else if(!strcasecmp(v->name, "smdiport")) {
+			if(reload) {
+				/* we are reloading, check if we are already
+				 * monitoring this interface, if we are we do
+				 * not want to start it again.  This also has
+				 * the side effect of not updating different
+				 * setting for the serial port, but it should
+				 * be trivial to rewrite this section so that
+				 * options on the port are changed without
+				 * restarting the interface.  Or the interface
+				 * could be restarted with out emptying the
+				 * queue. */
+				iface = ASTOBJ_CONTAINER_FIND(&smdi_ifaces, v->value);
+				if(iface) {
+					ast_log(LOG_NOTICE, "SMDI interface %s already running, not restarting\n", iface->name);
+					ASTOBJ_UNMARK(iface);
+					ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+					v = v->next;
+					continue;
+				}
+			}
+							
+			iface = malloc(sizeof(struct ast_smdi_interface));
+
+			ASTOBJ_INIT(iface);
+			ASTOBJ_CONTAINER_INIT(&iface->md_q);
+			ASTOBJ_CONTAINER_INIT(&iface->mwi_q);
+			iface->md_q.head = NULL;
+			iface->mwi_q.head = NULL;
+			iface->thread = AST_PTHREADT_NULL;
+			memset(&iface->mode, 0, sizeof(iface->mode));
+
+			ast_copy_string(iface->name, v->value, sizeof(iface->name));
+
+			iface->file = fopen(iface->name, "r");
+			if(!(iface->file)) {
+				ast_log(LOG_ERROR, "Error opening SMDI interface %s (%s)\n", iface->name, strerror(errno));
+				ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+		                v = v->next;
+				continue;
+			}
+			iface->fd = fileno(iface->file);
+
+			/* Set the proper attributes for our serial port. */
+
+			/* get the current attributes from the port */
+			if(tcgetattr(iface->fd, &iface->mode)) {
+				ast_log(LOG_ERROR, "Error getting atributes of %s (%s)\n", iface->name, strerror(errno));
+				ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+				v = v->next;
+				continue;
+			}
+
+			/* set the desired speed */
+			if(cfsetispeed(&iface->mode, baud_rate) || cfsetospeed(&iface->mode, baud_rate)) {
+				ast_log(LOG_ERROR, "Error setting baud rate on %s (%s)\n", iface->name, strerror(errno));
+				ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+				v = v->next;
+				continue;
+			}
+			
+			/* set the stop bits */
+			if(stopbits)
+			   iface->mode.c_cflag = iface->mode.c_cflag | CSTOPB;   /* set two stop bits */
+			else
+			   iface->mode.c_cflag = iface->mode.c_cflag & ~CSTOPB;  /* set one stop bit */
+
+			/* set the parity */
+			iface->mode.c_cflag = (iface->mode.c_cflag & ~PARENB & ~PARODD) | paritybit;
+
+			/* set the character size */
+			iface->mode.c_cflag = (iface->mode.c_cflag & ~CSIZE) | charsize;
+			
+			/* commit the desired attributes */
+			if(tcsetattr(iface->fd, TCSAFLUSH, &iface->mode)) {
+				ast_log(LOG_ERROR, "Error setting attributes on %s (%s)\n", iface->name, strerror(errno));
+				ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+				v = v->next;
+				continue;
+			}
+
+			/* set the msdstrip */
+			iface->msdstrip = msdstrip;
+
+			/* set the message expiry time */
+			iface->msg_expiry = msg_expiry;
+
+                        /* start the listner thread */
+			if(option_verbose > 2)
+				ast_verbose(VERBOSE_PREFIX_3 "Starting SMDI monitor thread for %s\n", iface->name);
+			if(ast_pthread_create(&iface->thread, NULL, smdi_read, iface)) {
+				ast_log(LOG_ERROR, "Error starting SMDI monitor thread for %s\n", iface->name);
+				ASTOBJ_UNREF(iface, ast_smdi_interface_destroy);
+		                v = v->next;
+				continue;
+			}
+			ASTOBJ_CONTAINER_LINK(&smdi_ifaces, iface);
+			ast_mutex_lock(&localuser_lock);
+			localusecnt++;
+			ast_mutex_unlock(&localuser_lock);
+			ast_update_use_count();
+		} else {
+			ast_log(LOG_NOTICE, "Ignoring unknown option %s in %s\n", v->name, config_file);
+		}
+		v = v->next;
+	}
+	ast_config_destroy(conf);
+
+	/* Prune any interfaces we should no longer monitor. */
+	if(reload)
+		ASTOBJ_CONTAINER_PRUNE_MARKED(&smdi_ifaces, ast_smdi_interface_destroy);
+	
+	ASTOBJ_CONTAINER_RDLOCK(&smdi_ifaces);
+	if(!smdi_ifaces.head)
+		res = 1;
+	ASTOBJ_CONTAINER_UNLOCK(&smdi_ifaces);
+			
+	return res;
+}
+
+
+char *description(void)
+{
+	return (char *)tdesc;
+}
+
+int load_module(void)
+{
+	int res;
+
+	/* initilize our containers */
+	ASTOBJ_CONTAINER_INIT(&smdi_ifaces);
+	smdi_ifaces.head = NULL;
+
+	/* load the config and start the listener threads*/
+	res = smdi_load(0);
+	if(res < 0) {
+		return res;
+	} else if(res == 1) {
+		ast_log(LOG_WARNING, "No SMDI interfaces are available to listen on, not starting SDMI listener.\n");
+		return 0;
+	}
+
+	return 0;
+}
+
+int unload_module(void)
+{
+	/* this destructor stops any running smdi_read threads */
+	ASTOBJ_CONTAINER_DESTROYALL(&smdi_ifaces,ast_smdi_interface_destroy);
+	ASTOBJ_CONTAINER_DESTROY(&smdi_ifaces);
+
+	return 0;
+}
+
+int reload(void)
+{
+	int res;
+	res = smdi_load(1);
+
+	if(res < 0) {
+		return res;
+	} else if(res == 1) {
+		ast_log(LOG_WARNING, "No SMDI interfaces were specified to listen on, not starting SDMI listener.\n");
+		return 0;
+	}
+
+	/* notify the listner thread? */
+	return 0;
+}
+
+int usecount(void)
+{
+	int res;
+	STANDARD_USECOUNT(res);
+	return res;
+}
+
+char *key()
+{
+	return ASTERISK_GPL_KEY;
+}