[PATCH v2 0/4] Add support for RFCOMM in btmon

[PATCH v2 0/4] Add support for RFCOMM in btmon

[Gowtham Anandha Babu]

Adds an initial implementation for RFCOMM in Bluetooth monitor.

Implementation for Decoding MSC, RPN, RLS, PN, NSC frames 
will  be covered in the next patch-set.

*v1: Incorporated Johan comments.

*v2: changed FCS fetching by l2cap_frame_pull

Gowtham Anandha Babu (4):
  monitor/rfcomm: Add RFCOMM support to btmon
  monitor/rfcomm: Add support for printing RFCOMM hdr
  monitor/rfcomm: Add support for UIH frame decoding
  monitor/rfcomm: Add support for mcc frame decoding

 Makefile.tools     |   1 +
 android/Android.mk |   1 +
 monitor/l2cap.c    |   4 +
 monitor/l2cap.h    |   2 +
 monitor/rfcomm.c   | 275 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 283 insertions(+)
 create mode 100644 monitor/rfcomm.c

-- 
1.9.1

[PATCH v2 0/4] Add support for RFCOMM in btmon

[Gowtham Anandha Babu]

Adds an initial implementation for RFCOMM in Bluetooth monitor.

Implementation for Decoding MSC, RPN, RLS, PN, NSC frames 
will  be covered in the next patch-set.

*v1: Incorporated Johan comments.

*v2: changed FCS fetching by l2cap_frame_pull

Gowtham Anandha Babu (4):
  monitor/rfcomm: Add RFCOMM support to btmon
  monitor/rfcomm: Add support for printing RFCOMM hdr
  monitor/rfcomm: Add support for UIH frame decoding
  monitor/rfcomm: Add support for mcc frame decoding

 Makefile.tools     |   1 +
 android/Android.mk |   1 +
 monitor/l2cap.c    |   4 +
 monitor/l2cap.h    |   2 +
 monitor/rfcomm.c   | 275 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 283 insertions(+)
 create mode 100644 monitor/rfcomm.c

-- 
1.9.1

[PATCH v2 1/4] monitor/rfcomm: Add RFCOMM support to btmon

[Gowtham Anandha Babu]

Changes made to add initial code to support RFCOMM frame in btmon

btmon logs:

      RFCOMM: Set Async Balance Mode (SABM) (0x2f)
        01 1c                                            ..

      RFCOMM: Unnumbered Ack (UA)(0x63)
        01 d7                                            ..

      RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
        15 81 11 20 e0 27 00 9a 02 00 07 aa              ... .'......

      RFCOMM: Disconnect (DISC)(0x43)
        01 fd
---
 Makefile.tools     |   1 +
 android/Android.mk |   1 +
 monitor/l2cap.c    |   4 ++
 monitor/l2cap.h    |   2 +
 monitor/rfcomm.c   | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 140 insertions(+)
 create mode 100644 monitor/rfcomm.c

diff --git a/Makefile.tools b/Makefile.tools
index 42cccc6..75a6faa 100644
--- a/Makefile.tools
+++ b/Makefile.tools
@@ -26,6 +26,7 @@ monitor_btmon_SOURCES = monitor/main.c monitor/bt.h \
 				monitor/l2cap.h monitor/l2cap.c \
 				monitor/sdp.h monitor/sdp.c \
 				monitor/avctp.h monitor/avctp.c \
+				monitor/rfcomm.h monitor/rfcomm.c \
 				monitor/uuid.h monitor/uuid.c \
 				monitor/hwdb.h monitor/hwdb.c \
 				monitor/keys.h monitor/keys.c \
diff --git a/android/Android.mk b/android/Android.mk
index 64ed6b9..dff71f5 100644
--- a/android/Android.mk
+++ b/android/Android.mk
@@ -288,6 +288,7 @@ LOCAL_SRC_FILES := \
 	bluez/monitor/packet.c \
 	bluez/monitor/l2cap.c \
 	bluez/monitor/avctp.c \
+	bluez/monitor/rfcomm.c \
 	bluez/monitor/uuid.c \
 	bluez/monitor/sdp.c \
 	bluez/monitor/vendor.c \
diff --git a/monitor/l2cap.c b/monitor/l2cap.c
index c004d6b..ebdd20f 100644
--- a/monitor/l2cap.c
+++ b/monitor/l2cap.c
@@ -42,6 +42,7 @@
 #include "keys.h"
 #include "sdp.h"
 #include "avctp.h"
+#include "rfcomm.h"
 
 #define MAX_CHAN 64
 
@@ -2643,6 +2644,9 @@ static void l2cap_frame(uint16_t index, bool in, uint16_t handle,
 		case 0x0001:
 			sdp_packet(&frame);
 			break;
+		case 0x0003:
+			rfcomm_packet(&frame);
+			break;
 		case 0x001f:
 			att_packet(index, in, handle, cid, data, size);
 			break;
diff --git a/monitor/l2cap.h b/monitor/l2cap.h
index 5faaea6..c14aeef 100644
--- a/monitor/l2cap.h
+++ b/monitor/l2cap.h
@@ -153,3 +153,5 @@ static inline bool l2cap_frame_get_le64(struct l2cap_frame *frame,
 
 void l2cap_packet(uint16_t index, bool in, uint16_t handle, uint8_t flags,
 					const void *data, uint16_t size);
+
+void rfcomm_packet(const struct l2cap_frame *frame);
diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
new file mode 100644
index 0000000..155bde2
--- /dev/null
+++ b/monitor/rfcomm.c
@@ -0,0 +1,132 @@
+/*
+ *
+ *  BlueZ - Bluetooth protocol stack for Linux
+ *
+ *  Copyright (C) 2011-2014  Intel Corporation
+ *  Copyright (C) 2002-2010  Marcel Holtmann <marcel@holtmann.org>
+ *
+ *
+ *  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 2.1 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <inttypes.h>
+
+#include <bluetooth/bluetooth.h>
+
+#include "src/shared/util.h"
+#include "bt.h"
+#include "packet.h"
+#include "display.h"
+#include "l2cap.h"
+#include "uuid.h"
+#include "keys.h"
+#include "sdp.h"
+#include "rfcomm.h"
+
+struct rfcomm_lhdr {
+	uint8_t address;
+	uint8_t control;
+	uint16_t length;
+	uint8_t fcs;
+	uint8_t credits; /* only for UIH frame */
+} __attribute__((packed));
+
+struct rfcomm_frame {
+	struct rfcomm_lhdr hdr;
+	struct l2cap_frame l2cap_frame;
+};
+
+struct rfcomm_data {
+	uint8_t frame;
+	const char *str;
+};
+
+static const struct rfcomm_data rfcomm_table[] = {
+	{ 0x2f, "Set Async Balance Mode (SABM) " },
+	{ 0x63, "Unnumbered Ack (UA)" },
+	{ 0x0f, "Disconnect Mode (DM)" },
+	{ 0x43, "Disconnect (DISC)" },
+	{ 0xef, "Unnumbered Info with Header Check (UIH)" },
+	{ }
+};
+
+void rfcomm_packet(const struct l2cap_frame *frame)
+{
+	uint8_t ctype;
+	const char *frame_str, *frame_color;
+	struct l2cap_frame *l2cap_frame;
+	struct rfcomm_frame rfcomm_frame;
+	struct rfcomm_lhdr hdr;
+	const struct rfcomm_data *rfcomm_data = NULL;
+	int i;
+
+	l2cap_frame_pull(&rfcomm_frame.l2cap_frame, frame, 0);
+
+	l2cap_frame = &rfcomm_frame.l2cap_frame;
+
+	if (frame->size < 4)
+		goto fail;
+
+	if (!l2cap_frame_get_u8(l2cap_frame, &hdr.address) ||
+			!l2cap_frame_get_u8(l2cap_frame, &hdr.control))
+		goto fail;
+
+	/* Decoding frame type */
+	ctype = RFCOMM_GET_TYPE(hdr.control);
+
+	for (i = 0; rfcomm_table[i].str; i++) {
+		if (rfcomm_table[i].frame == ctype) {
+			rfcomm_data = &rfcomm_table[i];
+			break;
+		}
+	}
+
+	if (rfcomm_data) {
+		if (frame->in)
+			frame_color = COLOR_MAGENTA;
+		else
+			frame_color = COLOR_BLUE;
+		frame_str = rfcomm_data->str;
+	} else {
+		frame_color = COLOR_WHITE_BG;
+		frame_str = "Unknown";
+	}
+
+	if (!rfcomm_data) {
+		packet_hexdump(frame->data, frame->size);
+		return;
+	}
+
+	print_indent(6, frame_color, "RFCOMM: ", frame_str, COLOR_OFF,
+						"(0x%2.2x)", ctype);
+
+	rfcomm_frame.hdr = hdr;
+	packet_hexdump(l2cap_frame->data, l2cap_frame->size);
+	return;
+
+fail:
+	print_text(COLOR_ERROR, "Frame too short");
+	packet_hexdump(frame->data, frame->size);
+	return;
+}
-- 
1.9.1

[PATCH v2 2/4] monitor/rfcomm: Add support for printing RFCOMM hdr

[Gowtham Anandha Babu]

Changes made to decode RFCOMM hdr and print the same.

      RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
         Address: 0x01 cr 0 dlci 0x00
         Control: 0xef poll/final 0
         Length: 10
         FCS: 0xaa
        81 11 20 e0 27 00 9a 02 00 07 aa                 .. .'......
---
 monitor/rfcomm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 48 insertions(+), 4 deletions(-)

diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
index 155bde2..8149ab7 100644
--- a/monitor/rfcomm.c
+++ b/monitor/rfcomm.c
@@ -44,6 +44,11 @@
 #include "sdp.h"
 #include "rfcomm.h"
 
+#define GET_LEN8(length) ((length & 0xfe) >> 1)
+#define GET_LEN16(length) ((length & 0xfffe) >> 1)
+#define GET_CR(type)	((type & 0x02) >> 1)
+#define GET_PF(ctr) (((ctr) >> 4) & 0x1)
+
 struct rfcomm_lhdr {
 	uint8_t address;
 	uint8_t control;
@@ -57,6 +62,24 @@ struct rfcomm_frame {
 	struct l2cap_frame l2cap_frame;
 };
 
+static void print_rfcomm_hdr(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
+{
+	struct rfcomm_lhdr hdr = rfcomm_frame->hdr;
+
+	/* Address field */
+	print_field("%*cAddress: 0x%2.2x cr %d dlci 0x%2.2x", indent, ' ',
+					hdr.address, GET_CR(hdr.address),
+					RFCOMM_GET_DLCI(hdr.address));
+
+	/* Control field */
+	print_field("%*cControl: 0x%2.2x poll/final %d", indent, ' ',
+					hdr.control, GET_PF(hdr.control));
+
+	/* Length and FCS */
+	print_field("%*cLength: %d", indent, ' ', hdr.length);
+	print_field("%*cFCS: 0x%2.2x", indent, ' ', hdr.fcs);
+}
+
 struct rfcomm_data {
 	uint8_t frame;
 	const char *str;
@@ -73,9 +96,9 @@ static const struct rfcomm_data rfcomm_table[] = {
 
 void rfcomm_packet(const struct l2cap_frame *frame)
 {
-	uint8_t ctype;
+	uint8_t ctype, length, ex_length, indent = 1;
 	const char *frame_str, *frame_color;
-	struct l2cap_frame *l2cap_frame;
+	struct l2cap_frame *l2cap_frame, tmp_frame;
 	struct rfcomm_frame rfcomm_frame;
 	struct rfcomm_lhdr hdr;
 	const struct rfcomm_data *rfcomm_data = NULL;
@@ -89,7 +112,23 @@ void rfcomm_packet(const struct l2cap_frame *frame)
 		goto fail;
 
 	if (!l2cap_frame_get_u8(l2cap_frame, &hdr.address) ||
-			!l2cap_frame_get_u8(l2cap_frame, &hdr.control))
+			!l2cap_frame_get_u8(l2cap_frame, &hdr.control) ||
+			!l2cap_frame_get_u8(l2cap_frame, &length))
+		goto fail;
+
+	/* length maybe 1 or 2 octets */
+	if (RFCOMM_TEST_EA(length))
+		hdr.length = (uint16_t) GET_LEN8(length);
+	else {
+		if (!l2cap_frame_get_u8(l2cap_frame, &ex_length))
+			goto fail;
+		hdr.length = ((uint16_t)length << 8) | ex_length;
+		hdr.length = GET_LEN16(hdr.length);
+	}
+
+	l2cap_frame_pull(&tmp_frame, l2cap_frame, l2cap_frame->size-1);
+
+	if(!l2cap_frame_get_u8(&tmp_frame, &hdr.fcs))
 		goto fail;
 
 	/* Decoding frame type */
@@ -122,7 +161,12 @@ void rfcomm_packet(const struct l2cap_frame *frame)
 						"(0x%2.2x)", ctype);
 
 	rfcomm_frame.hdr = hdr;
-	packet_hexdump(l2cap_frame->data, l2cap_frame->size);
+	print_rfcomm_hdr(&rfcomm_frame, indent);
+
+	/* UIH frame */
+	if(ctype == 0xef)
+		packet_hexdump(l2cap_frame->data, l2cap_frame->size);
+
 	return;
 
 fail:
-- 
1.9.1

[PATCH v2 3/4] monitor/rfcomm: Add support for UIH frame decoding

[Gowtham Anandha Babu]

Changes made to decode UIH frame in btmon.

In below UIH frame, MCC frame is present, so no credits field is printed.

      RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
         Address: 0x01 cr 0 dlci 0x00
         Control: 0xef poll/final 0
         Length: 10
         FCS: 0xaa
        81 11 20 e0 27 00 9a 02 00 07 aa                 .. .'......

In this UIH frame, no MCC frame, so credits field is printed.

      RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
         Address: 0x81 cr 0 dlci 0x20
         Control: 0xff poll/final 1
         Length: 0
         FCS: 0x1e
         Credits : 33
---
 monitor/rfcomm.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
index 8149ab7..aa6ba36 100644
--- a/monitor/rfcomm.c
+++ b/monitor/rfcomm.c
@@ -80,6 +80,31 @@ static void print_rfcomm_hdr(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
 	print_field("%*cFCS: 0x%2.2x", indent, ' ', hdr.fcs);
 }
 
+static bool uih_frame(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
+{
+	uint8_t credits;
+	struct l2cap_frame *frame = &rfcomm_frame->l2cap_frame;
+	struct rfcomm_lhdr *hdr = &rfcomm_frame->hdr;
+
+	if (!RFCOMM_GET_CHANNEL(hdr->address)) {
+		/* MCC frame parser implementation */
+		goto done;
+	}
+
+	/* fetching credits from UIH frame */
+	if (GET_PF(hdr->control)) {
+		if (!l2cap_frame_get_u8(frame, &credits))
+			return false;
+		hdr->credits = credits;
+		print_field("%*cCredits: %d", indent, ' ', hdr->credits);
+		return true;
+	}
+
+done:
+	packet_hexdump(frame->data, frame->size);
+	return true;
+}
+
 struct rfcomm_data {
 	uint8_t frame;
 	const char *str;
@@ -164,8 +189,9 @@ void rfcomm_packet(const struct l2cap_frame *frame)
 	print_rfcomm_hdr(&rfcomm_frame, indent);
 
 	/* UIH frame */
-	if(ctype == 0xef)
-		packet_hexdump(l2cap_frame->data, l2cap_frame->size);
+	if (ctype == 0xef)
+		if (!uih_frame(&rfcomm_frame, indent))
+			goto fail;
 
 	return;
 
-- 
1.9.1

[PATCH v2 4/4] monitor/rfcomm: Add support for mcc frame decoding

[Gowtham Anandha Babu]

Changes made to decode MCC frame in RFCOMM for btmon.

      RFCOMM: Unnumbered Info with Header Check (UIH)(0xef)
         Address: 0x01 cr 0 dlci 0x00
         Control: 0xef poll/final 0
         Length: 10
         FCS: 0xaa
         MCC Message type: DLC Parameter Negotiation RSP(0x20)
           Length: 8
        20 e0 27 00 9a 02 00 07 aa                        .'......
---
 monitor/rfcomm.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 78 insertions(+), 5 deletions(-)

diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
index aa6ba36..881ae5e 100644
--- a/monitor/rfcomm.c
+++ b/monitor/rfcomm.c
@@ -44,6 +44,12 @@
 #include "sdp.h"
 #include "rfcomm.h"
 
+static char *cr_str[] = {
+	"RSP",
+	"CMD"
+};
+
+#define CR_STR(type) cr_str[GET_CR(type)]
 #define GET_LEN8(length) ((length & 0xfe) >> 1)
 #define GET_LEN16(length) ((length & 0xfffe) >> 1)
 #define GET_CR(type)	((type & 0x02) >> 1)
@@ -57,8 +63,14 @@ struct rfcomm_lhdr {
 	uint8_t credits; /* only for UIH frame */
 } __attribute__((packed));
 
+struct rfcomm_lmcc {
+	uint8_t type;
+	uint16_t length;
+} __attribute__((packed));
+
 struct rfcomm_frame {
 	struct rfcomm_lhdr hdr;
+	struct rfcomm_lmcc mcc;
 	struct l2cap_frame l2cap_frame;
 };
 
@@ -80,16 +92,78 @@ static void print_rfcomm_hdr(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
 	print_field("%*cFCS: 0x%2.2x", indent, ' ', hdr.fcs);
 }
 
+struct mcc_data {
+	uint8_t type;
+	const char *str;
+};
+
+static const struct mcc_data mcc_table[] = {
+	{ 0x08, "Test Command" },
+	{ 0x28, "Flow Control On Command" },
+	{ 0x18, "Flow Control Off Command" },
+	{ 0x38, "Modem Status Command" },
+	{ 0x24, "Remote Port Negotiation Command" },
+	{ 0x14, "Remote Line Status" },
+	{ 0x20, "DLC Parameter Negotiation" },
+	{ 0x04, "Non Supported Command" },
+	{ }
+};
+
+static inline bool mcc_frame(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
+{
+	uint8_t length, ex_length, type;
+	const char *type_str;
+	int i;
+	struct l2cap_frame *frame = &rfcomm_frame->l2cap_frame;
+	struct rfcomm_lmcc mcc;
+	const struct mcc_data *mcc_data = NULL;
+
+	if (!l2cap_frame_get_u8(frame, &mcc.type) ||
+			!l2cap_frame_get_u8(frame, &length))
+		return false;
+
+	if (RFCOMM_TEST_EA(length))
+		mcc.length = (uint16_t) GET_LEN8(length);
+	else {
+		if (!l2cap_frame_get_u8(frame, &ex_length))
+			return false;
+		mcc.length = ((uint16_t) length << 8) | ex_length;
+		mcc.length = GET_LEN16(mcc.length);
+	}
+
+	type = RFCOMM_GET_MCC_TYPE(mcc.type);
+
+	for (i = 0; mcc_table[i].str; i++) {
+		if (mcc_table[i].type == type) {
+			mcc_data = &mcc_table[i];
+			break;
+		}
+	}
+
+	if (mcc_data)
+		type_str = mcc_data->str;
+	else
+		type_str = "Unknown";
+
+	print_field("%*cMCC Message type: %s %s(0x%2.2x)", indent, ' ',
+				type_str, CR_STR(mcc.type), type);
+
+	print_field("%*cLength: %d", indent+2, ' ', mcc.length);
+
+	rfcomm_frame->mcc = mcc;
+	packet_hexdump(frame->data, frame->size);
+
+	return true;
+}
+
 static bool uih_frame(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
 {
 	uint8_t credits;
 	struct l2cap_frame *frame = &rfcomm_frame->l2cap_frame;
 	struct rfcomm_lhdr *hdr = &rfcomm_frame->hdr;
 
-	if (!RFCOMM_GET_CHANNEL(hdr->address)) {
-		/* MCC frame parser implementation */
-		goto done;
-	}
+	if (!RFCOMM_GET_CHANNEL(hdr->address))
+		return mcc_frame(rfcomm_frame, indent);
 
 	/* fetching credits from UIH frame */
 	if (GET_PF(hdr->control)) {
@@ -100,7 +174,6 @@ static bool uih_frame(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
 		return true;
 	}
 
-done:
 	packet_hexdump(frame->data, frame->size);
 	return true;
 }
-- 
1.9.1

Re: [PATCH v2 0/4] Add support for RFCOMM in btmon

[Luiz Augusto von Dentz]

Hi Gowtham,

On Fri, Nov 7, 2014 at 5:43 PM, Gowtham Anandha Babu
<gowtham.ab@samsung.com> wrote:
> Adds an initial implementation for RFCOMM in Bluetooth monitor.
>
> Implementation for Decoding MSC, RPN, RLS, PN, NSC frames
> will  be covered in the next patch-set.
>
> *v1: Incorporated Johan comments.
>
> *v2: changed FCS fetching by l2cap_frame_pull
>
> Gowtham Anandha Babu (4):
>   monitor/rfcomm: Add RFCOMM support to btmon
>   monitor/rfcomm: Add support for printing RFCOMM hdr
>   monitor/rfcomm: Add support for UIH frame decoding
>   monitor/rfcomm: Add support for mcc frame decoding
>
>  Makefile.tools     |   1 +
>  android/Android.mk |   1 +
>  monitor/l2cap.c    |   4 +
>  monitor/l2cap.h    |   2 +
>  monitor/rfcomm.c   | 275 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 283 insertions(+)
>  create mode 100644 monitor/rfcomm.c
>
> --
> 1.9.1

Applied, thanks.


-- 
Luiz Augusto von Dentz