From 2b2b708d4330010bbaac5a36309fb0926c5129b2 Mon Sep 17 00:00:00 2001
From: Naveen Albert <asterisk@phreaknet.org>
Date: Wed, 22 Sep 2021 00:18:08 +0000
Subject: [PATCH] app_mf: Add full tech-agnostic MF support

Adds tech-agnostic support for MF signaling by adding
MF sender and receiver applications as well as Dial
integration.

ASTERISK-29496-mf #do-not-close

Change-Id: I61962b359b8ec4cfd05df877ddf9f5b8f71927a4
---
 apps/app_dial.c                   |  65 +++--
 apps/app_mf.c                     | 398 ++++++++++++++++++++----------
 doc/CHANGES-staging/app_mf_mf.txt |   5 +
 include/asterisk/app.h            |  33 +++
 include/asterisk/channel.h        |  32 +++
 main/app.c                        | 123 +++++++++
 main/channel.c                    |  76 +++++-
 7 files changed, 588 insertions(+), 144 deletions(-)
 create mode 100644 doc/CHANGES-staging/app_mf_mf.txt

diff --git a/apps/app_dial.c b/apps/app_dial.c
index 526a3af16b..f073af3b9a 100644
--- a/apps/app_dial.c
+++ b/apps/app_dial.c
@@ -156,6 +156,8 @@
 					<argument name="called" />
 					<argument name="calling" />
 					<argument name="progress" />
+					<argument name="mfprogress" />
+					<argument name="mfwink" />
 					<para>Send the specified DTMF strings <emphasis>after</emphasis> the called
 					party has answered, but before the call gets bridged.  The
 					<replaceable>called</replaceable> DTMF string is sent to the called party, and the
@@ -163,6 +165,15 @@
 					can be used alone.  If <replaceable>progress</replaceable> is specified, its DTMF is sent
 					to the called party immediately after receiving a <literal>PROGRESS</literal> message.</para>
 					<para>See <literal>SendDTMF</literal> for valid digits.</para>
+					<para>If <replaceable>mfprogress</replaceable> is specified, its MF is sent
+					to the called party immediately after receiving a <literal>PROGRESS</literal> message.
+					If <replaceable>mfwink</replaceable> is specified, its MF is sent
+					to the called party immediately after receiving a <literal>WINK</literal> message.</para>
+					<para>See <literal>SendMF</literal> for valid digits.</para>
+				</option>
+				<option name="E">
+					<para>Enable echoing of sent MF or SF digits back to caller (e.g. "hearpulsing").
+					Used in conjunction with the D option.</para>
 				</option>
 				<option name="e">
 					<para>Execute the <literal>h</literal> extension for peer after the call ends</para>
@@ -499,7 +510,6 @@
 			answered, if it has not already been answered. These two channels will then
 			be active in a bridged call. All other channels that were requested will then
 			be hung up.</para>
-
 			<para>Unless there is a timeout specified, the Dial application will wait
 			indefinitely until one of the called channels answers, the user hangs up, or
 			if all of the called channels are busy or unavailable. Dialplan execution will
@@ -512,7 +522,6 @@
 			If the <variable>OUTBOUND_GROUP_ONCE</variable> variable is set, all peer channels created by this
 			application will be put into that group (as in <literal>Set(GROUP()=...</literal>). Unlike <variable>OUTBOUND_GROUP</variable>,
 			however, the variable will be unset after use.</para>
-
 			<example title="Dial with 30 second timeout">
 			 same => n,Dial(PJSIP/alice,30)
 			</example>
@@ -534,28 +543,22 @@
 			</example>
 			<example title="Dial with pre-dial subroutines">
 			[default]
-
 			exten => callee_channel,1,NoOp(ARG1=${ARG1} ARG2=${ARG2})
 			 same => n,Log(NOTICE, I'm called on channel ${CHANNEL} prior to it starting the dial attempt)
 			 same => n,Return()
-
 			exten => called_channel,1,NoOp(ARG1=${ARG1} ARG2=${ARG2})
 			 same => n,Log(NOTICE, I'm called on outbound channel ${CHANNEL} prior to it being used to dial someone)
 			 same => n,Return()
-
 			exten => _X.,1,NoOp()
 			 same => n,Dial(PJSIP/alice,,b(default^called_channel^1(my_gosub_arg1^my_gosub_arg2))B(default^callee_channel^1(my_gosub_arg1^my_gosub_arg2)))
 			 same => n,Hangup()
 			</example>
 			<example title="Dial with post-answer subroutine executed on outbound channel">
 			[my_gosub_routine]
-
 			exten => s,1,NoOp(ARG1=${ARG1} ARG2=${ARG2})
 			 same => n,Playback(hello)
 			 same => n,Return()
-
 			[default]
-
 			exten => _X.,1,NoOp()
 			 same => n,Dial(PJSIP/alice,,U(my_gosub_routine^my_gosub_arg1^my_gosub_arg2))
 			 same => n,Hangup()
@@ -717,6 +720,7 @@ enum {
 #define OPT_PREDIAL_CALLER   (1LLU << 42)
 #define OPT_RING_WITH_EARLY_MEDIA (1LLU << 43)
 #define OPT_HANGUPCAUSE      (1LLU << 44)
+#define OPT_HEARPULSING      (1LLU << 45)
 
 enum {
 	OPT_ARG_ANNOUNCE = 0,
@@ -752,6 +756,7 @@ AST_APP_OPTIONS(dial_exec_options, BEGIN_OPTIONS
 	AST_APP_OPTION('c', OPT_CANCEL_ELSEWHERE),
 	AST_APP_OPTION('d', OPT_DTMF_EXIT),
 	AST_APP_OPTION_ARG('D', OPT_SENDDTMF, OPT_ARG_SENDDTMF),
+	AST_APP_OPTION('E', OPT_HEARPULSING),
 	AST_APP_OPTION('e', OPT_PEER_H),
 	AST_APP_OPTION_ARG('f', OPT_FORCECLID, OPT_ARG_FORCECLID),
 	AST_APP_OPTION_ARG('F', OPT_CALLEE_GO_ON, OPT_ARG_CALLEE_GO_ON),
@@ -1208,6 +1213,8 @@ static struct ast_channel *wait_for_answer(struct ast_channel *in,
 	char *opt_args[],
 	struct privacy_args *pa,
 	const struct cause_args *num_in, int *result, char *dtmf_progress,
+	char *mf_progress, char *mf_wink,
+	const int hearpulsing,
 	const int ignore_cc,
 	struct ast_party_id *forced_clid, struct ast_party_id *stored_clid,
 	struct ast_bridge_config *config)
@@ -1227,7 +1234,7 @@ static struct ast_channel *wait_for_answer(struct ast_channel *in,
 	int cc_frame_received = 0;
 	int num_ringing = 0;
 	int sent_ring = 0;
-	int sent_progress = 0;
+	int sent_progress = 0, sent_wink = 0;
 	struct timeval start = ast_tvnow();
 	SCOPE_ENTER(3, "%s\n", ast_channel_name(in));
 
@@ -1565,6 +1572,14 @@ static struct ast_channel *wait_for_answer(struct ast_channel *in,
 						ast_channel_unlock(in);
 						sent_progress = 1;
 
+						if (!ast_strlen_zero(mf_progress)) {
+							ast_verb(3,
+								"Sending MF '%s' to %s as result of "
+								"receiving a PROGRESS message.\n",
+								mf_progress, hearpulsing ? "parties" : "called party");
+							ast_mf_stream(c, (hearpulsing ? NULL : in),
+							(hearpulsing ? in : NULL), mf_progress, 50, 55, 120, 65, 0);
+						}
 						if (!ast_strlen_zero(dtmf_progress)) {
 							ast_verb(3,
 								"Sending DTMF '%s' to the called party as result of "
@@ -1575,6 +1590,20 @@ static struct ast_channel *wait_for_answer(struct ast_channel *in,
 					}
 					ast_channel_publish_dial(in, c, NULL, "PROGRESS");
 					break;
+				case AST_CONTROL_WINK:
+					ast_verb(3, "%s winked, passing it to %s\n", ast_channel_name(c), ast_channel_name(in));
+					if (!sent_wink) {
+						sent_wink = 1;
+						if (!ast_strlen_zero(mf_wink)) {
+							ast_verb(3,
+								"Sending MF '%s' to %s as result of "
+								"receiving a WINK message.\n",
+								mf_wink, (hearpulsing ? "parties" : "called party"));
+							ast_mf_stream(c, (hearpulsing ? NULL : in),
+							(hearpulsing ? in : NULL), mf_wink, 50, 55, 120, 65, 0);
+						}
+					}
+					break;
 				case AST_CONTROL_VIDUPDATE:
 				case AST_CONTROL_SRCUPDATE:
 				case AST_CONTROL_SRCCHANGE:
@@ -2132,9 +2161,7 @@ static int setup_privacy_args(struct privacy_args *pa,
 			/* the file doesn't exist yet. Let the caller submit his
 			   vocal intro for posterity */
 			/* priv-recordintro script:
-
 			   "At the tone, please say your name:"
-
 			*/
 			int silencethreshold = ast_dsp_get_threshold_from_settings(THRESHOLD_SILENCE);
 			ast_answer(chan);
@@ -2249,7 +2276,8 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 
 	struct ast_bridge_config config = { { 0, } };
 	struct timeval calldurationlimit = { 0, };
-	char *dtmfcalled = NULL, *dtmfcalling = NULL, *dtmf_progress=NULL;
+	char *dtmfcalled = NULL, *dtmfcalling = NULL, *dtmf_progress = NULL;
+	char *mf_progress = NULL, *mf_wink = NULL;
 	struct privacy_args pa = {
 		.sentringing = 0,
 		.privdb_val = 0,
@@ -2385,9 +2413,11 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 	}
 
 	if (ast_test_flag64(&opts, OPT_SENDDTMF) && !ast_strlen_zero(opt_args[OPT_ARG_SENDDTMF])) {
-		dtmf_progress = opt_args[OPT_ARG_SENDDTMF];
-		dtmfcalled = strsep(&dtmf_progress, ":");
-		dtmfcalling = strsep(&dtmf_progress, ":");
+		mf_wink = opt_args[OPT_ARG_SENDDTMF];
+		dtmfcalled = strsep(&mf_wink, ":");
+		dtmfcalling = strsep(&mf_wink, ":");
+		dtmf_progress = strsep(&mf_wink, ":");
+		mf_progress = strsep(&mf_wink, ":");
 	}
 
 	if (ast_test_flag64(&opts, OPT_DURATION_LIMIT) && !ast_strlen_zero(opt_args[OPT_ARG_DURATION_LIMIT])) {
@@ -2864,7 +2894,8 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 	}
 
 	peer = wait_for_answer(chan, &out_chans, &to, peerflags, opt_args, &pa, &num, &result,
-		dtmf_progress, ignore_cc, &forced_clid, &stored_clid, &config);
+		dtmf_progress, mf_progress, mf_wink, (ast_test_flag64(&opts, OPT_HEARPULSING) ? 1 : 0),
+		ignore_cc, &forced_clid, &stored_clid, &config);
 
 	if (!peer) {
 		if (result) {
@@ -3542,4 +3573,4 @@ AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Dialing Application",
 	.load = load_module,
 	.unload = unload_module,
 	.requires = "ccss",
-);
+);
\ No newline at end of file
diff --git a/apps/app_mf.c b/apps/app_mf.c
index 671fc1c936..3caf8a42d2 100644
--- a/apps/app_mf.c
+++ b/apps/app_mf.c
@@ -18,7 +18,7 @@
 
 /*! \file
  *
- * \brief App to send MF digits
+ * \brief MF sender and receiver applications
  *
  * \author Naveen Albert <asterisk@phreaknet.org>
  *
@@ -31,22 +31,93 @@
 
 #include "asterisk.h"
 
+#include "asterisk/file.h"
 #include "asterisk/pbx.h"
-#include "asterisk/module.h"
-#include "asterisk/app.h"
 #include "asterisk/channel.h"
+#include "asterisk/dsp.h"
+#include "asterisk/app.h"
+#include "asterisk/module.h"
 #include "asterisk/indications.h"
+#include "asterisk/conversions.h"
 
 /*** DOCUMENTATION
+	<application name="ReceiveMF" language="en_US">
+		<synopsis>
+			Detects MF digits on a channel and saves them to a variable.
+		</synopsis>
+		<syntax>
+			<parameter name="variable" required="true">
+				<para>The input digits will be stored in the given
+				<replaceable>variable</replaceable> name.</para>
+			</parameter>
+			<parameter name="timeout">
+				<para>The number of seconds to wait for all digits, if greater
+				than <literal>0</literal>. Can be floating point. Default
+				is no timeout.</para>
+			</parameter>
+			<parameter name="options">
+				<optionlist>
+					<option name="d">
+						<para>Delay audio by a frame to try to extra quelch.</para>
+					</option>
+					<option name="l">
+						<para>Receive digits even if a key pulse (KP) has not yet
+						been received. By default, this application will ignore
+						all other digits until a KP has been received.</para>
+					</option>
+					<option name="k">
+						<para>Do not return a character for the KP digit.</para>
+					</option>
+					<option name="m">
+						<para>Mute conference.</para>
+					</option>
+					<option name="o">
+						<para>Enable override. Repeated KPs will clear all previous digits.</para>
+					</option>
+					<option name="q">
+						<para>Quelch MF from in-band.</para>
+					</option>
+					<option name="r">
+						<para>"Radio" mode (relaxed MF).</para>
+					</option>
+					<option name="s">
+						<para>Do not return a character for ST digits.</para>
+					</option>
+				</optionlist>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Reads a ST, STP, ST2P, or ST3P-terminated string of MF digits from
+			the user in to the given <replaceable>variable</replaceable>.</para>
+			<para>This application does not automatically answer the channel and
+			should be preceded with <literal>Answer</literal> or
+			<literal>Progress</literal> as needed.</para>
+			<variablelist>
+				<variable name="RECEIVEMFSTATUS">
+					<para>This is the status of the read operation.</para>
+					<value name="START" />
+					<value name="ERROR" />
+					<value name="HANGUP" />
+					<value name="MAXDIGITS" />
+					<value name="TIMEOUT" />
+				</variable>
+			</variablelist>
+		</description>
+		<see-also>
+			<ref type="application">Read</ref>
+			<ref type="application">SendMF</ref>
+		</see-also>
+	</application>
 	<application name="SendMF" language="en_US">
 		<synopsis>
-			Sends arbitrary MF digits
+			Sends arbitrary MF digits on the current or specified channel.
 		</synopsis>
 		<syntax>
 			<parameter name="digits" required="true">
-				<para>List of digits 0-9,*#ABC to send; also f or F for a flash-hook
-				if the channel supports flash-hook, and w or W for a wink if the channel
-				supports wink.</para>
+				<para>List of digits 0-9,*#ABC to send; w for a half-second pause,
+				also f or F for a flash-hook if the channel supports flash-hook,
+				h or H for 250 ms of 2600 Hz,
+				and W for a wink if the channel supports wink.</para>
 				<para>Key pulse and start digits are not included automatically.
 				* is used for KP, # for ST, A for STP, B for ST2P, and C for ST3P.</para>
 			</parameter>
@@ -70,12 +141,13 @@
 			<para>It will send all digits or terminate if it encounters an error.</para>
 		</description>
 		<see-also>
+			<ref type="application">ReceiveMF</ref>
 			<ref type="application">SendDTMF</ref>
 		</see-also>
 	</application>
 	<manager name="PlayMF" language="en_US">
 		<synopsis>
-			Play MF signal on a specific channel.
+			Play MF digit on a specific channel.
 		</synopsis>
 		<syntax>
 			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
@@ -95,140 +167,218 @@
 	</manager>
  ***/
 
+enum read_option_flags {
+	OPT_DELAY = (1 << 0),
+	OPT_MUTE = (1 << 1),
+	OPT_QUELCH = (1 << 2),
+	OPT_RELAXED = (1 << 3),
+	OPT_LAX_KP = (1 << 4),
+	OPT_PROCESS = (1 << 5),
+	OPT_NO_KP = (1 << 6),
+	OPT_NO_ST = (1 << 7),
+	OPT_KP_OVERRIDE = (1 << 8),
+};
+
+AST_APP_OPTIONS(read_app_options, {
+	AST_APP_OPTION('d', OPT_DELAY),
+	AST_APP_OPTION('l', OPT_LAX_KP),
+	AST_APP_OPTION('k', OPT_NO_KP),
+	AST_APP_OPTION('m', OPT_MUTE),
+	AST_APP_OPTION('o', OPT_KP_OVERRIDE),
+	AST_APP_OPTION('p', OPT_PROCESS),
+	AST_APP_OPTION('q', OPT_QUELCH),
+	AST_APP_OPTION('r', OPT_RELAXED),
+	AST_APP_OPTION('s', OPT_NO_ST),
+});
+
+static const char *readmf_name = "ReceiveMF";
 static const char sendmf_name[] = "SendMF";
 
-#define DEFAULT_EMULATE_MF_DURATION 35
 #define MF_BETWEEN_MS 50
 #define MF_DURATION 55
 #define MF_KP_DURATION 120
 #define MF_ST_DURATION 65
 
-static int senddigit_mf_begin(struct ast_channel *chan, char digit)
-{
-	static const char * const mf_tones[] = {
-		"1300+1500", /* 0 */
-		"700+900",   /* 1 */
-		"700+1100",  /* 2 */
-		"900+1100",  /* 3 */
-		"700+1300",  /* 4 */
-		"900+1300",  /* 5 */
-		"1100+1300", /* 6 */
-		"700+1500",  /* 7 */
-		"900+1500",  /* 8 */
-		"1100+1500", /* 9 */
-		"1100+1700", /* * (KP) */
-		"1500+1700", /* # (ST) */
-		"900+1700",  /* A (STP) */
-		"1300+1700", /* B (ST2P) */
-		"700+1700"   /* C (ST3P) */
-	};
-
-	if (digit >= '0' && digit <='9') {
-		ast_playtones_start(chan, 0, mf_tones[digit-'0'], 0);
-	} else if (digit == '*') {
-		ast_playtones_start(chan, 0, mf_tones[10], 0);
-	} else if (digit == '#') {
-		ast_playtones_start(chan, 0, mf_tones[11], 0);
-	} else if (digit == 'A') {
-		ast_playtones_start(chan, 0, mf_tones[12], 0);
-	} else if (digit == 'B') {
-		ast_playtones_start(chan, 0, mf_tones[13], 0);
-	} else if (digit == 'C') {
-		ast_playtones_start(chan, 0, mf_tones[14], 0);
-	} else {
-		/* not handled */
-		ast_log(LOG_WARNING, "Unable to generate MF tone '%c' for '%s'\n", digit, ast_channel_name(chan));
+/*!
+ * \brief Detects MF digits on channel using DSP, terminated by ST, STP, ST2P, or ST3P
+ *
+ * \param chan channel on which to read digits
+ * \param buf Buffer in which to store digits
+ * \param buflen Size of buffer
+ * \param timeout ms to wait for all digits before giving up
+ * \param features Any additional DSP features to use
+ * \param override Start over if we receive additional KPs
+ * \param no_kp Don't include KP in the output
+ * \param no_st Don't include start digits in the output
+ *
+ * \retval 0 if successful
+ * \retval -1 if unsuccessful.
+ */
+static int read_mf_digits(struct ast_channel *chan, char *buf, int buflen, int timeout, int features, int laxkp, int override, int no_kp, int no_st) {
+	struct ast_dsp *dsp;
+	struct ast_frame *frame = NULL;
+	struct timeval start;
+	int remaining_time = timeout;
+	int digits_read = 0;
+	int is_start_digit = 0;
+	char *str = buf;
+
+	if (!(dsp = ast_dsp_new())) {
+		ast_log(LOG_WARNING, "Unable to allocate DSP!\n");
+		pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "ERROR");
+		return -1;
 	}
-
+	ast_dsp_set_features(dsp, DSP_FEATURE_DIGIT_DETECT);
+	ast_dsp_set_digitmode(dsp, DSP_DIGITMODE_MF | features);
+
+	start = ast_tvnow();
+	*str = 0; /* start with empty output buffer */
+
+	/* based on app_read and generic_fax_exec from res_fax */
+	while (timeout == 0 || remaining_time > 0) {
+		if (timeout > 0) {
+			remaining_time = ast_remaining_ms(start, timeout);
+			if (remaining_time <= 0) {
+				pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "TIMEOUT");
+				break;
+			}
+		}
+		if (digits_read >= (buflen - 1)) { /* we don't have room to store any more digits (very unlikely to happen for a legitimate reason) */
+			/* This result will probably not be usable, so status should not be START */
+			pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "MAXDIGITS");
+			break;
+		}
+		/* ast_waitfordigit only waits for DTMF frames, we need to do DSP on voice frames */
+		if (ast_waitfor(chan, 1000) > 0) {
+			frame = ast_read(chan);
+			if (!frame) {
+				ast_debug(1, "Channel '%s' did not return a frame; probably hung up.\n", ast_channel_name(chan));
+				pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "HANGUP");
+				break;
+			} else if (frame->frametype == AST_FRAME_VOICE) {
+				frame = ast_dsp_process(chan, dsp, frame);
+				/* AST_FRAME_DTMF is used all over the DSP code for DTMF, MF, fax, etc.
+					It's used because we can use the frame to store the digit detected.
+					All this means is that we received something we care about. */
+				if (frame->frametype == AST_FRAME_DTMF) {
+					char result = frame->subclass.integer;
+					if (digits_read == 0 && !laxkp && result != '*') {
+						ast_debug(1, "Received MF digit, but no KP yet, ignoring: %c\n", result);
+						ast_frfree(frame);
+						continue;
+					}
+					ast_debug(1, "Received MF digit: %c\n", result);
+					if (result == '*') {
+						/* We received an additional KP, start over? */
+						if (override && digits_read > 0) {
+							ast_debug(1, "Received another KP, starting over\n");
+							str = buf;
+							*str = 0;
+							digits_read = 1; /* we just detected a KP */
+						} else {
+							digits_read++;
+						}
+						/* if we were told not to include the KP digit in the output string, then skip it */
+						if (no_kp) {
+							ast_frfree(frame);
+							continue;
+						}
+					} else {
+						digits_read++;
+					}
+					is_start_digit = (strchr("#", result) || strchr("A", result) || strchr("B", result) || strchr("C", result));
+					/* if we were told not to include the ST digit in the output string, then skip it */
+					if (!no_st || !is_start_digit) {
+						*str++ = result; /* won't write past allotted memory, because of buffer check at top of loop */
+						*str = 0;
+					}
+					/* we received a ST digit (ST, STP, ST2P, or ST3P), so we're done */
+					if (is_start_digit) {
+						pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "START");
+						ast_frfree(frame);
+						break;
+					}
+					/* only free frame if it was a DSP match. The MF itself should not be muted. */
+					ast_frfree(frame);
+				}
+			}
+		} else {
+			pbx_builtin_setvar_helper(chan, "RECEIVEMFSTATUS", "HANGUP");
+		}
+	}
+	ast_dsp_free(dsp);
+	ast_debug(3, "channel '%s' - event loop stopped { timeout: %d, remaining_time: %d }\n", ast_channel_name(chan), timeout, remaining_time);
 	return 0;
 }
 
-static int senddigit_mf_end(struct ast_channel *chan)
+static int read_mf_exec(struct ast_channel *chan, const char *data)
 {
-	if (ast_channel_generator(chan)) {
-		ast_playtones_stop(chan);
-		return 0;
+#define BUFFER_SIZE 256
+	char tmp[BUFFER_SIZE] = "";
+	int to = 0;
+	double tosec;
+	struct ast_flags flags = {0};
+	char *argcopy = NULL;
+	int features = 0;
+
+	AST_DECLARE_APP_ARGS(arglist,
+		AST_APP_ARG(variable);
+		AST_APP_ARG(timeout);
+		AST_APP_ARG(options);
+	);
+
+	if (ast_strlen_zero(data)) {
+		ast_log(LOG_WARNING, "ReceiveMF requires an argument (variable)\n");
+		return -1;
 	}
-	return -1;
-}
 
-static int mysleep(struct ast_channel *chan, int ms, int is_external)
-{
-	return is_external ? usleep(ms * 1000) : ast_safe_sleep(chan, ms);
-}
+	argcopy = ast_strdupa(data);
 
-static int senddigit_mf(struct ast_channel *chan, char digit, unsigned int duration,
-	unsigned int durationkp, unsigned int durationst, int is_external)
-{
-	if (duration < DEFAULT_EMULATE_MF_DURATION) {
-		duration = DEFAULT_EMULATE_MF_DURATION;
+	AST_STANDARD_APP_ARGS(arglist, argcopy);
+
+	if (!ast_strlen_zero(arglist.options)) {
+		ast_app_parse_options(read_app_options, &flags, NULL, arglist.options);
 	}
-	if (ast_channel_tech(chan)->send_digit_begin) {
-		if (digit == '*') {
-			duration = durationkp;
-		} else if (digit == '#' || digit == 'A' || digit == 'B' || digit == 'C') {
-			duration = durationst;
+
+	if (!ast_strlen_zero(arglist.timeout)) {
+		tosec = atof(arglist.timeout);
+		if (tosec <= 0) {
+			to = 0;
+		} else {
+			to = tosec * 1000.0;
 		}
-		senddigit_mf_begin(chan, digit);
-		mysleep(chan, duration, is_external);
 	}
-	return senddigit_mf_end(chan);
-}
-
-static int mf_stream(struct ast_channel *chan, const char *digits, int between, unsigned int duration,
-	unsigned int durationkp, unsigned int durationst, int is_external)
-{
-	const char *ptr;
-	int res;
-	struct ast_silence_generator *silgen = NULL;
 
-	if (!between) {
-		between = 100;
+	if (ast_strlen_zero(arglist.variable)) {
+		ast_log(LOG_WARNING, "Invalid! Usage: ReceiveMF(variable[,timeout][,option])\n");
+		return -1;
 	}
 
-	/* Need a quiet time before sending digits. */
-	if (ast_opt_transmit_silence) {
-		silgen = ast_channel_start_silence_generator(chan);
+	if (ast_test_flag(&flags, OPT_DELAY)) {
+		features |= DSP_DIGITMODE_MUTEMAX;
 	}
-	res = mysleep(chan, 100, is_external);
-	if (res) {
-		goto mf_stream_cleanup;
+
+	if (ast_test_flag(&flags, OPT_MUTE)) {
+		features |= DSP_DIGITMODE_MUTECONF;
 	}
 
-	for (ptr = digits; *ptr; ptr++) {
-		if (strchr("0123456789*#ABCwWfF", *ptr)) {
-			if (*ptr == 'f' || *ptr == 'F') {
-				/* ignore return values if not supported by channel */
-				ast_indicate(chan, AST_CONTROL_FLASH);
-			} else if (*ptr == 'w' || *ptr == 'W') {
-				/* ignore return values if not supported by channel */
-				ast_indicate(chan, AST_CONTROL_WINK);
-			} else {
-				/* Character represents valid MF */
-				senddigit_mf(chan, *ptr, duration, durationkp, durationst, is_external);
-			}
-			/* pause between digits */
-			/* The DSP code in Asterisk does not currently properly receive repeated tones
-				if no audio is sent in the middle. Simply sending audio (even 0 Hz)
-				works around this limitation and guarantees the correct behavior.
-				*/
-			ast_playtones_start(chan, 0, "0", 0);
-			res = mysleep(chan, between, is_external);
-			senddigit_mf_end(chan);
-			if (res) {
-				break;
-			}
-		} else {
-			ast_log(LOG_WARNING, "Illegal MF character '%c' in string. (0-9*#ABCwWfF allowed)\n", *ptr);
-		}
+	if (!ast_test_flag(&flags, OPT_QUELCH)) {
+		features |= DSP_DIGITMODE_NOQUELCH;
 	}
 
-mf_stream_cleanup:
-	if (silgen) {
-		ast_channel_stop_silence_generator(chan, silgen);
+	if (ast_test_flag(&flags, OPT_RELAXED)) {
+		features |= DSP_DIGITMODE_RELAXDTMF;
 	}
 
-	return res;
+	read_mf_digits(chan, tmp, BUFFER_SIZE, to, features, (ast_test_flag(&flags, OPT_LAX_KP)),
+		(ast_test_flag(&flags, OPT_KP_OVERRIDE)), (ast_test_flag(&flags, OPT_NO_KP)), (ast_test_flag(&flags, OPT_NO_ST)));
+	pbx_builtin_setvar_helper(chan, arglist.variable, tmp);
+	if (!ast_strlen_zero(tmp)) {
+		ast_verb(3, "MF digits received: '%s'\n", tmp);
+	} else {
+		ast_verb(3, "No MF digits received.\n");
+	}
+	return 0;
 }
 
 static int sendmf_exec(struct ast_channel *chan, const char *vdata)
@@ -283,16 +433,9 @@ static int sendmf_exec(struct ast_channel *chan, const char *vdata)
 			chan_autoservice = chan;
 		}
 	}
-	if (chan_autoservice && ast_autoservice_start(chan_autoservice)) {
-		ast_channel_cleanup(chan_found);
-		return -1;
-	}
-	res = mf_stream(chan_dest, args.digits, dinterval <= 0 ? MF_BETWEEN_MS : dinterval,
+	res = ast_mf_stream(chan_dest, chan_autoservice, NULL, args.digits, dinterval <= 0 ? MF_BETWEEN_MS : dinterval,
 		duration <= 0 ? MF_DURATION : duration, durationkp <= 0 ? MF_KP_DURATION : durationkp,
 		durationst <= 0 ? MF_ST_DURATION : durationst, 0);
-	if (chan_autoservice && ast_autoservice_stop(chan_autoservice)) {
-		res = -1;
-	}
 	ast_channel_cleanup(chan_found);
 
 	return chan_autoservice ? 0 : res;
@@ -330,7 +473,8 @@ static int manager_play_mf(struct mansession *s, const struct message *m)
 		return 0;
 	}
 
-	senddigit_mf(chan, *digit, duration_ms, duration_ms, duration_ms, 1);
+	ast_mf_stream(chan, NULL, NULL, digit, 0, duration_ms, duration_ms, duration_ms, 1);
+
 	chan = ast_channel_unref(chan);
 
 	astman_send_ack(s, m, "MF successfully queued");
@@ -342,7 +486,8 @@ static int unload_module(void)
 {
 	int res;
 
-	res = ast_unregister_application(sendmf_name);
+	res = ast_unregister_application(readmf_name);
+	res |= ast_unregister_application(sendmf_name);
 	res |= ast_manager_unregister("PlayMF");
 
 	return res;
@@ -352,10 +497,11 @@ static int load_module(void)
 {
 	int res;
 
-	res = ast_manager_register_xml("PlayMF", EVENT_FLAG_CALL, manager_play_mf);
+	res = ast_register_application_xml(readmf_name, read_mf_exec);
 	res |= ast_register_application_xml(sendmf_name, sendmf_exec);
+	res |= ast_manager_register_xml("PlayMF", EVENT_FLAG_CALL, manager_play_mf);
 
 	return res;
 }
 
-AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Send MF digits Application");
+AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "MF Sender and Receiver Applications");
diff --git a/doc/CHANGES-staging/app_mf_mf.txt b/doc/CHANGES-staging/app_mf_mf.txt
new file mode 100644
index 0000000000..3168f2adbc
--- /dev/null
+++ b/doc/CHANGES-staging/app_mf_mf.txt
@@ -0,0 +1,5 @@
+Subject: app_mf
+
+Adds MF receiver and sender applications to support
+the R1 MF signaling protocol, including integration
+with the Dial application.
diff --git a/include/asterisk/app.h b/include/asterisk/app.h
index fab080c3e2..55b73863e5 100644
--- a/include/asterisk/app.h
+++ b/include/asterisk/app.h
@@ -941,6 +941,39 @@ void ast_replace_sigchld(void);
  */
 void ast_unreplace_sigchld(void);
 
+/*!
+ * \brief Send a string of MF digits to a channel
+ *
+ * \param chan    The channel that will receive the MF digits.
+ * \param peer    (optional) Peer channel that will be autoserviced while the
+ *                primary channel is receiving MF
+ * \param chan2   A second channel that will simultaneously receive MF digits.
+ *                This option may only be used if is_external is 0.
+ * \param digits  This is a string of characters representing the MF digits
+ *                to be sent to the channel.  Valid characters are
+ *                "0123456789*#abcdABCD".  Note: You can pass arguments 'f' or
+ *                'F', if you want to Flash the channel (if supported by the
+ *                channel), or 'w' or 'W' to add a wink (if supported by the
+ *                channel).
+ * \param between This is the number of milliseconds to wait in between each
+ *                MF digit.  If zero milliseconds is specified, then the
+ *                default value of 50 will be used.
+ * \param duration This is the duration that each numeric MF digit should have.
+ *                 Default value is 55.
+ * \param durationkp This is the duration that each KP digit should have. Default
+ *                is 120.
+ * \param durationst This is the duration that each ST, STP, ST2P, or ST3P digit
+ *                should have. Default is 65.
+ * \param is_external 1 if called by a thread that is not the channel's media
+ *                handler thread, 0 if called by the channel's media handler
+ *                thread.
+ *
+ * \retval 0 on success.
+ * \retval -1 on failure or a channel hung up.
+ */
+int ast_mf_stream(struct ast_channel *chan, struct ast_channel *peer, struct ast_channel *chan2, const char *digits,
+	int between, unsigned int duration, unsigned int durationkp, unsigned int durationst, int is_external);
+
 /*!
  * \brief Send a string of DTMF digits to a channel
  *
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index e9dcf6a3c2..59d25a842e 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -2242,6 +2242,30 @@ int ast_sendtext_data(struct ast_channel *chan, struct ast_msg_data *msg);
  */
 int ast_recvchar(struct ast_channel *chan, int timeout);
 
+/*!
+ * \brief End sending an MF digit to a channel.
+ * \param chan channel to act upon
+ * \return Returns 0 on success, -1 on failure
+ */
+int ast_senddigit_mf_end(struct ast_channel *chan);
+
+/*!
+ * \brief Send an MF digit to a channel.
+ *
+ * \param chan channel to act upon
+ * \param digit the MF digit to send, encoded in ASCII
+ * \param duration the duration of a numeric digit ending in ms
+ * \param duration the duration of a KP digit ending in ms
+ * \param duration the duration of a ST, STP, ST2P, or ST3P digit ending in ms
+ * \param is_external 1 if called by a thread that is not the channel's media
+ *                handler thread, 0 if called by the channel's media handler
+ *                thread.
+ *
+ * \return 0 on success, -1 on failure
+ */
+int ast_senddigit_mf(struct ast_channel *chan, char digit, unsigned int duration,
+	unsigned int durationkp, unsigned int durationst, int is_external);
+
 /*!
  * \brief Send a DTMF digit to a channel.
  *
@@ -2269,6 +2293,14 @@ int ast_senddigit(struct ast_channel *chan, char digit, unsigned int duration);
  */
 int ast_senddigit_external(struct ast_channel *chan, char digit, unsigned int duration);
 
+/*!
+ * \brief Send an MF digit to a channel.
+ * \param chan channel to act upon
+ * \param digit the MF digit to send, encoded in ASCII
+ * \return 0 on success, -1 on failure
+ */
+int ast_senddigit_mf_begin(struct ast_channel *chan, char digit);
+
 /*!
  * \brief Send a DTMF digit to a channel.
  * \param chan channel to act upon
diff --git a/main/app.c b/main/app.c
index 326357999d..c20e3705d9 100644
--- a/main/app.c
+++ b/main/app.c
@@ -830,6 +830,115 @@ static int external_sleep(struct ast_channel *chan, int ms)
 	return 0;
 }
 
+static int mf_stream(struct ast_channel *chan, struct ast_channel *chan2, const char *digits, int between, unsigned int duration,
+	unsigned int durationkp, unsigned int durationst, int is_external)
+{
+	const char *ptr;
+	int res;
+	struct ast_silence_generator *silgen = NULL, *silgen2 = NULL;
+	int (*my_sleep)(struct ast_channel *chan, int ms);
+
+	if (is_external) {
+		my_sleep = external_sleep;
+	} else {
+		my_sleep = ast_safe_sleep;
+	}
+
+	if (!between) {
+		between = 100;
+	}
+
+	/* Need a quiet time before sending digits. */
+	if (ast_opt_transmit_silence) {
+		silgen = ast_channel_start_silence_generator(chan);
+		if (chan2) {
+			silgen2 = ast_channel_start_silence_generator(chan2);
+		}
+	}
+	if (chan2) {
+		ast_autoservice_start(chan2);
+	}
+	res = my_sleep(chan, 100);
+	if (chan2) {
+		ast_autoservice_stop(chan2);
+	}
+	if (res) {
+		goto mf_stream_cleanup;
+	}
+
+	for (ptr = digits; *ptr; ptr++) {
+		if (*ptr == 'w') {
+			/* 'w' -- wait half a second */
+			res = my_sleep(chan, 500);
+			if (res) {
+				break;
+			}
+		} else if (*ptr == 'h' || *ptr == 'H') {
+			/* 'h' -- 2600 Hz for half a second, but
+				only to far end of trunk, not near end */
+			ast_playtones_start(chan, 0, "2600", 0);
+			if (chan2) {
+				ast_playtones_start(chan2, 0, "0", 0);
+				ast_autoservice_start(chan2);
+			}
+			res = my_sleep(chan, 250);
+			ast_senddigit_mf_end(chan);
+			if (chan2) {
+				ast_autoservice_stop(chan2);
+				ast_senddigit_mf_end(chan2);
+			}
+			if (res) {
+				break;
+			}
+		} else if (strchr("0123456789*#ABCwWfF", *ptr)) {
+			if (*ptr == 'f' || *ptr == 'F') {
+				/* ignore return values if not supported by channel */
+				ast_indicate(chan, AST_CONTROL_FLASH);
+			} else if (*ptr == 'W') {
+				/* ignore return values if not supported by channel */
+				ast_indicate(chan, AST_CONTROL_WINK);
+			} else {
+				/* Character represents valid MF */
+				ast_senddigit_mf(chan, *ptr, duration, durationkp, durationst, is_external);
+				if (chan2) {
+					ast_senddigit_mf(chan2, *ptr, duration, durationkp, durationst, is_external);
+				}
+			}
+			/* pause between digits */
+			/* The DSP code in Asterisk does not currently properly receive repeated tones
+				if no audio is sent in the middle. Simply sending audio (even 0 Hz)
+				works around this limitation and guarantees the correct behavior.
+				*/
+			ast_playtones_start(chan, 0, "0", 0);
+			if (chan2) {
+				ast_playtones_start(chan2, 0, "0", 0);
+				ast_autoservice_start(chan2);
+			}
+			res = my_sleep(chan, between);
+			ast_senddigit_mf_end(chan);
+			if (chan2) {
+				ast_autoservice_stop(chan2);
+				ast_senddigit_mf_end(chan2);
+			}
+			if (res) {
+				break;
+			}
+		} else {
+			ast_log(LOG_WARNING, "Illegal MF character '%c' in string. (0-9*#ABCwWfFhH allowed)\n", *ptr);
+		}
+	}
+
+mf_stream_cleanup:
+	if (silgen) {
+		ast_channel_stop_silence_generator(chan, silgen);
+	}
+	if (silgen2) {
+		ast_channel_stop_silence_generator(chan2, silgen2);
+	}
+
+	return res;
+}
+
 static int dtmf_stream(struct ast_channel *chan, const char *digits, int between, unsigned int duration, int is_external)
 {
 	const char *ptr;
@@ -898,6 +1007,20 @@ dtmf_stream_cleanup:
 	return res;
 }
 
+int ast_mf_stream(struct ast_channel *chan, struct ast_channel *peer, struct ast_channel *chan2, const char *digits,
+	int between, unsigned int duration, unsigned int durationkp, unsigned int durationst, int is_external)
+{
+	int res;
+	if (!is_external && !chan2 && peer && ast_autoservice_start(peer)) {
+		return -1;
+	}
+	res = mf_stream(chan, chan2, digits, between, duration, durationkp, durationst, is_external);
+	if (!is_external && !chan2 && peer && ast_autoservice_stop(peer)) {
+		res = -1;
+	}
+	return res;
+}
+
 int ast_dtmf_stream(struct ast_channel *chan, struct ast_channel *peer, const char *digits, int between, unsigned int duration)
 {
 	int res;
diff --git a/main/channel.c b/main/channel.c
index 36afb7fe1b..4d104cef59 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -97,10 +97,14 @@ unsigned long global_fin, global_fout;
 AST_THREADSTORAGE(state2str_threadbuf);
 #define STATE2STR_BUFSIZE   32
 
-/*! Default amount of time to use when emulating a digit as a begin and end
+/*! Default amount of time to use when emulating a DTMF digit as a begin and end
  *  100ms */
 #define AST_DEFAULT_EMULATE_DTMF_DURATION 100
 
+/*! Default amount of time to use when emulating an MF digit as a begin and end
+ *  55ms */
+#define DEFAULT_EMULATE_MF_DURATION 55
+
 #define DEFAULT_AMA_FLAGS AST_AMA_DOCUMENTATION
 
 /*! Minimum amount of time between the end of the last digit and the beginning
@@ -4856,6 +4860,45 @@ int ast_sendtext(struct ast_channel *chan, const char *text)
 	return rc;
 }
 
+int ast_senddigit_mf_begin(struct ast_channel *chan, char digit)
+{
+	static const char * const mf_tones[] = {
+		"1300+1500", /* 0 */
+		"700+900",   /* 1 */
+		"700+1100",  /* 2 */
+		"900+1100",  /* 3 */
+		"700+1300",  /* 4 */
+		"900+1300",  /* 5 */
+		"1100+1300", /* 6 */
+		"700+1500",  /* 7 */
+		"900+1500",  /* 8 */
+		"1100+1500", /* 9 */
+		"1100+1700", /* * (KP) */
+		"1500+1700", /* # (ST) */
+		"900+1700",  /* A (STP) */
+		"1300+1700", /* B (ST2P) */
+		"700+1700"   /* C (ST3P) */
+	};
+
+	if (digit >= '0' && digit <='9') {
+		ast_playtones_start(chan, 0, mf_tones[digit-'0'], 0);
+	} else if (digit == '*') {
+		ast_playtones_start(chan, 0, mf_tones[10], 0);
+	} else if (digit == '#') {
+		ast_playtones_start(chan, 0, mf_tones[11], 0);
+	} else if (digit == 'A') {
+		ast_playtones_start(chan, 0, mf_tones[12], 0);
+	} else if (digit == 'B') {
+		ast_playtones_start(chan, 0, mf_tones[13], 0);
+	} else if (digit == 'C') {
+		ast_playtones_start(chan, 0, mf_tones[14], 0);
+	} else {
+		/* not handled */
+		ast_log(LOG_WARNING, "Unable to generate MF tone '%c' for '%s'\n", digit, ast_channel_name(chan));
+	}
+	return 0;
+}
+
 int ast_senddigit_begin(struct ast_channel *chan, char digit)
 {
 	/* Device does not support DTMF tones, lets fake
@@ -4925,6 +4968,37 @@ int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duratio
 	return 0;
 }
 
+int ast_senddigit_mf_end(struct ast_channel *chan)
+{
+	if (ast_channel_generator(chan)) {
+		ast_playtones_stop(chan);
+		return 0;
+	}
+	return -1;
+}
+
+int ast_senddigit_mf(struct ast_channel *chan, char digit, unsigned int duration,
+	unsigned int durationkp, unsigned int durationst, int is_external)
+{
+	if (duration < DEFAULT_EMULATE_MF_DURATION) {
+		duration = DEFAULT_EMULATE_MF_DURATION;
+	}
+	if (ast_channel_tech(chan)->send_digit_begin) {
+		if (digit == '*') {
+			duration = durationkp;
+		} else if (digit == '#' || digit == 'A' || digit == 'B' || digit == 'C') {
+			duration = durationst;
+		}
+		ast_senddigit_mf_begin(chan, digit);
+		if (is_external) {
+			usleep(duration * 1000);
+		} else {
+			ast_safe_sleep(chan, duration);
+		}
+	}
+	return ast_senddigit_mf_end(chan);
+}
+
 int ast_senddigit(struct ast_channel *chan, char digit, unsigned int duration)
 {
 	if (duration < AST_DEFAULT_EMULATE_DTMF_DURATION) {
-- 
2.47.2