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/*
*
* 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"
#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;
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;
};
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);
}
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;
};
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, length, ex_length, indent = 1;
const char *frame_str, *frame_color;
struct l2cap_frame *l2cap_frame, tmp_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) ||
!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 */
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;
print_rfcomm_hdr(&rfcomm_frame, indent);
/* UIH frame */
if (ctype == 0xef)
if (!uih_frame(&rfcomm_frame, indent))
goto fail;
return;
fail:
print_text(COLOR_ERROR, "Frame too short");
packet_hexdump(frame->data, frame->size);
return;
}
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