monitor/rfcomm: Add RFCOMM support to btmon

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

1 files changed, 132 insertions, 0 deletions

diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
new file mode 100644
index 000000000..155bde200
--- /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;
+}