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ofono/gatchat/gsm0710.c

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/*
*
* AT chat library with GLib integration
*
* Copyright (C) 2009 Intel Corporation. All rights reserved.
* Copyright (C) 2009 Trolltech ASA.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; 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 <alloca.h>
#include <string.h>
#include <stdio.h>
#include "gsm0710.h"
/* Frame types and subtypes */
#define GSM0710_OPEN_CHANNEL 0x3F
#define GSM0710_CLOSE_CHANNEL 0x53
#define GSM0710_DATA 0xEF
#define GSM0710_DATA_ALT 0x03
#define GSM0710_STATUS_SET 0xE3
#define GSM0710_STATUS_ACK 0xE1
#define GSM0710_TERMINATE_BYTE1 0xC3
#define GSM0710_TERMINATE_BYTE2 0x01
/* Status flags */
#define GSM0710_FC 0x02
#define GSM0710_DTR 0x04
#define GSM0710_DSR 0x04
#define GSM0710_RTS 0x08
#define GSM0710_CTS 0x08
#define GSM0710_DCD 0x80
/* Initialize a GSM 07.10 context, in preparation for startup */
void gsm0710_initialize(struct gsm0710_context *ctx)
{
ctx->mode = GSM0710_MODE_BASIC;
ctx->frame_size = GSM0710_DEFAULT_FRAME_SIZE;
ctx->port_speed = 115200;
ctx->server = 0;
ctx->buffer_used = 0;
memset(ctx->used_channels, 0, sizeof(ctx->used_channels));
ctx->reinit_detect = 0;
ctx->reinit_detect_len = 0;
ctx->user_data = 0;
ctx->fd = -1;
ctx->at_command = 0;
ctx->read = 0;
ctx->write = 0;
ctx->deliver_data = 0;
ctx->deliver_status = 0;
ctx->debug_message = 0;
ctx->open_channel = 0;
ctx->close_channel = 0;
ctx->terminate = 0;
ctx->packet_filter = 0;
}
/* Determine if a channel is in use */
static int is_channel_used(struct gsm0710_context *ctx, int channel)
{
int index = channel / 32;
return ((ctx->used_channels[index] & (1L << (channel % 32))) != 0);
}
/* Mark a channel as used */
static void mark_channel_used(struct gsm0710_context *ctx, int channel)
{
int index = channel / 32;
ctx->used_channels[index] |= (1L << (channel % 32));
}
/* Mark a channel as unused */
static void mark_channel_unused(struct gsm0710_context *ctx, int channel)
{
int index = channel / 32;
ctx->used_channels[index] &= ~(1L << (channel % 32));
}
/* Write a debug message */
static void gsm0710_debug(struct gsm0710_context *ctx, const char *msg)
{
if (ctx->debug_message)
ctx->debug_message(ctx, msg);
}
/* Set the "reinitialize detect" string to "str". When "str" is
encountered in the input stream, the AT+CMUX command will be
re-sent and the multiplexer re-started. This is needed for
devices that drop out of multiplexer mode due to suspend/wakeup/etc.
The data at "str" must persist until the context is destroyed */
void gsm0710_set_reinit_detect(struct gsm0710_context *ctx, const char *str)
{
ctx->reinit_detect = str;
ctx->reinit_detect_len = (str ? strlen(str) : 0);
}
static const unsigned char crc_table[256] = {
0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
};
static unsigned char gsm0710_compute_crc(const unsigned char *data, int len)
{
int sum = 0xFF;
while (len > 0) {
sum = crc_table[(sum ^ *data++) & 0xFF];
--len;
}
return (~sum & 0xFF);
}
/* Write a raw GSM 07.10 frame to the underlying device */
static void gsm0710_write_frame(struct gsm0710_context *ctx, int channel,
int type, const unsigned char *data, int len)
{
unsigned char *frame = alloca(ctx->frame_size * 2 + 8);
int size;
if (len > ctx->frame_size)
len = ctx->frame_size;
if (ctx->mode) {
int temp, crc;
frame[0] = 0x7E;
frame[1] = ((channel << 2) | 0x03);
frame[2] = type;
crc = gsm0710_compute_crc(frame + 1, 2);
if (type == 0x7E || type == 0x7D) {
/* Need to quote the type field now that crc has been computed */
frame[2] = 0x7D;
frame[3] = (type ^ 0x20);
size = 4;
} else {
size = 3;
}
while (len > 0) {
temp = *data++ & 0xFF;
--len;
if (temp != 0x7E && temp != 0x7D) {
frame[size++] = temp;
} else {
frame[size++] = 0x7D;
frame[size++] = (temp ^ 0x20);
}
}
if (crc != 0x7E && crc != 0x7D) {
frame[size++] = crc;
} else {
frame[size++] = 0x7D;
frame[size++] = (crc ^ 0x20);
}
frame[size++] = 0x7E;
} else {
int header_size;
frame[0] = 0xF9;
frame[1] = ((channel << 2) | 0x03);
frame[2] = type;
if (len <= 127) {
frame[3] = ((len << 1) | 0x01);
header_size = size = 4;
} else {
frame[3] = (len << 1);
frame[4] = (len >> 7);
header_size = size = 5;
}
if (len > 0) {
memcpy(frame + size, data, len);
size += len;
}
/* Note: GSM 07.10 says that the CRC is only computed over the header */
frame[size++] = gsm0710_compute_crc(frame + 1, header_size - 1);
frame[size++] = 0xF9;
}
if (ctx->write)
ctx->write(ctx, frame, size);
}
/* Start up the GSM 07.10 session on the underlying device.
If "send_cmux" is non-zero, then send the AT+CMUX command.
Otherwise the underlying device is assumed to already be
in multiplexing mode. Returns zero if the AT+CMUX failed */
int gsm0710_startup(struct gsm0710_context *ctx, int send_cmux)
{
int channel;
char command[64];
/* Discard any data in the buffer, in case of restart */
ctx->buffer_used = 0;
/* Send the appropriate AT+CMUX command */
if (send_cmux) {
int speed;
switch (ctx->port_speed) {
case 9600:
speed = 1;
break;
case 19200:
speed = 2;
break;
case 38400:
speed = 3;
break;
case 57600:
speed = 4;
break;
case 115200:
speed = 5;
break;
case 230400:
speed = 6;
break;
default:
speed = 5;
break;
}
sprintf(command, "AT+CMUX=%d,0,%d,%d",
ctx->mode, speed, ctx->frame_size);
if (!ctx->at_command || !ctx->at_command(ctx, command)) {
gsm0710_debug(ctx,
"could not initialize multiplexing with AT+CMUX");
return 0;
}
}
/* Open the control channel */
gsm0710_write_frame(ctx, 0, GSM0710_OPEN_CHANNEL, NULL, 0);
/* Open previously-used channels if this is a reinit.
Send "ERROR" on re-opened channels, to cause higher
layers to abort pending AT commands */
for (channel = 1; channel <= GSM0710_MAX_CHANNELS; ++channel) {
if (is_channel_used(ctx, channel)) {
gsm0710_write_frame(ctx, channel,
GSM0710_OPEN_CHANNEL, NULL, 0);
if (ctx->deliver_data)
ctx->deliver_data(ctx, channel,
"\r\nERROR\r\n", 9);
}
}
return 1;
}
/* Shut down the GSM 07.10 session, closing all channels */
void gsm0710_shutdown(struct gsm0710_context *ctx)
{
static const unsigned char terminate[2] = { GSM0710_TERMINATE_BYTE1,
GSM0710_TERMINATE_BYTE2 };
if (!ctx->server) {
int channel;
for (channel = 1; channel <= GSM0710_MAX_CHANNELS; ++channel) {
if (is_channel_used(ctx, channel)) {
gsm0710_write_frame(ctx, channel,
GSM0710_CLOSE_CHANNEL, NULL, 0);
}
}
gsm0710_write_frame(ctx, 0, GSM0710_DATA, terminate, 2);
}
memset(ctx->used_channels, 0, sizeof(ctx->used_channels));
}
/* Open a specific channel. Returns non-zero if successful */
int gsm0710_open_channel(struct gsm0710_context *ctx, int channel)
{
if (channel <= 0 || channel > GSM0710_MAX_CHANNELS)
return 0; /* Invalid channel number */
if (is_channel_used(ctx, channel))
return 1; /* Channel is already open */
mark_channel_used(ctx, channel);
if (!ctx->server)
gsm0710_write_frame(ctx, channel,
GSM0710_OPEN_CHANNEL, NULL, 0);
return 1;
}
/* Close a specific channel */
void gsm0710_close_channel(struct gsm0710_context *ctx, int channel)
{
if (channel <= 0 || channel > GSM0710_MAX_CHANNELS)
return; /* Invalid channel number */
if (!is_channel_used(ctx, channel))
return; /* Channel is already closed */
mark_channel_unused(ctx, channel);
if (!ctx->server)
gsm0710_write_frame(ctx, channel,
GSM0710_CLOSE_CHANNEL, NULL, 0);
}
/* Determine if a specific channel is open */
int gsm0710_is_channel_open(struct gsm0710_context *ctx, int channel)
{
if (channel <= 0 || channel > GSM0710_MAX_CHANNELS)
return 0; /* Invalid channel number */
return is_channel_used(ctx, channel);
}
/* Process an incoming GSM 07.10 packet */
static int gsm0710_packet(struct gsm0710_context *ctx, int channel, int type,
const unsigned char *data, int len)
{
if (ctx->packet_filter &&
ctx->packet_filter(ctx, channel, type, data, len)) {
/* The filter has extracted and processed the packet */
return 1;
}
if (type == 0xEF || type == 0x03) {
if (channel >= 1 && channel <= GSM0710_MAX_CHANNELS &&
is_channel_used(ctx, channel)) {
/* Ordinary data packet */
if (ctx->deliver_data)
ctx->deliver_data(ctx, channel, data, len);
} else if (channel == 0) {
/* An embedded command or response on channel 0 */
if (len >= 2 && data[0] == GSM0710_STATUS_SET) {
return gsm0710_packet(ctx, channel,
GSM0710_STATUS_ACK,
data + 2, len - 2);
} else if (len >= 2 && data[0] == 0xC3 && ctx->server) {
/* Incoming terminate request on server side */
for (channel = 1; channel <= GSM0710_MAX_CHANNELS; ++channel) {
if (is_channel_used(ctx, channel)) {
if (ctx->close_channel)
ctx->close_channel(ctx, channel);
}
}
memset(ctx->used_channels, 0,
sizeof(ctx->used_channels));
if (ctx->terminate)
ctx->terminate(ctx);
return 0;
} else if (len >= 2 && data[0] == 0x43) {
/* Test command from other side - send the same bytes back */
unsigned char *resp = alloca(len);
memcpy(resp, data, len);
resp[0] = 0x41; /* Clear the C/R bit in the response */
gsm0710_write_frame(ctx, 0, GSM0710_DATA,
resp, len);
}
}
} else if (type == GSM0710_STATUS_ACK && channel == 0) {
unsigned char resp[33];
/* Status change message */
if (len >= 2) {
/* Handle status changes on other channels */
channel = ((data[0] & 0xFC) >> 2);
if (channel >= 1 && channel <= GSM0710_MAX_CHANNELS &&
is_channel_used(ctx, channel)) {
if (ctx->deliver_status)
ctx->deliver_status(ctx, channel,
data[1] & 0xFF);
}
}
/* Send the response to the status change request to ACK it */
gsm0710_debug(ctx,
"received status line signal, sending response");
if (len > 31)
len = 31;
resp[0] = GSM0710_STATUS_ACK;
resp[1] = ((len << 1) | 0x01);
memcpy(resp + 2, data, len);
gsm0710_write_frame(ctx, 0, GSM0710_DATA, resp, len + 2);
} else if (type == (0x3F & 0xEF) && ctx->server) {
/* Incoming channel open request on server side */
if (channel >= 1 && channel <= GSM0710_MAX_CHANNELS) {
if (!is_channel_used(ctx, channel)) {
mark_channel_used(ctx, channel);
if (ctx->open_channel)
ctx->open_channel(ctx, channel);
}
}
} else if (type == (0x53 & 0xEF) && ctx->server) {
/* Incoming channel close request on server side */
if (channel >= 1 && channel <= GSM0710_MAX_CHANNELS) {
if (is_channel_used(ctx, channel)) {
mark_channel_unused(ctx, channel);
if (ctx->close_channel)
ctx->close_channel(ctx, channel);
}
}
}
return 1;
}
/* Function that is called when the underlying device is ready to be read.
A callback will be made to ctx->read to get the data for processing */
void gsm0710_ready_read(struct gsm0710_context *ctx)
{
int len, posn, posn2, header_size, channel, type;
/* Read more data from the underlying serial device */
if (!ctx->read)
return;
len = ctx->read(ctx, ctx->buffer + ctx->buffer_used,
sizeof(ctx->buffer) - ctx->buffer_used);
if (len <= 0)
return;
/* Update the buffer size */
ctx->buffer_used += len;
/* Check for the re-initialization detection string */
if (!ctx->server && ctx->reinit_detect_len &&
len >= ctx->reinit_detect_len &&
!memcmp(ctx->buffer, ctx->reinit_detect, ctx->reinit_detect_len)) {
gsm0710_startup(ctx, 1);
return;
}
/* Break the incoming data up into packets */
posn = 0;
while (posn < ctx->buffer_used) {
if (ctx->buffer[posn] == 0xF9) {
/* Basic format: skip additional 0xF9 bytes between frames */
while ((posn + 1) < ctx->buffer_used &&
ctx->buffer[posn + 1] == 0xF9) {
++posn;
}
/* We need at least 4 bytes for the header */
if ((posn + 4) > ctx->buffer_used)
break;
/* The low bit of the second byte should be 1,
which indicates a short channel number */
if ((ctx->buffer[posn + 1] & 0x01) == 0) {
++posn;
continue;
}
/* Get the packet length and validate it */
len = (ctx->buffer[posn + 3] >> 1) & 0x7F;
if ((ctx->buffer[posn + 3] & 0x01) != 0) {
/* Single-byte length indication */
header_size = 3;
} else {
/* Double-byte length indication */
if ((posn + 5) > ctx->buffer_used)
break;
len |= ((int)(ctx->buffer[posn + 4])) << 7;
header_size = 4;
}
if ((posn + header_size + 2 + len) > ctx->buffer_used)
break;
/* Verify the packet header checksum */
if (((gsm0710_compute_crc(ctx->buffer + posn + 1,
header_size) ^ ctx->buffer[posn + len + header_size + 1]) & 0xFF) != 0) {
gsm0710_debug(ctx,
"*** GSM 07.10 checksum check failed ***");
posn += len + header_size + 2;
continue;
}
/* Get the channel number and packet type from the header */
channel = (ctx->buffer[posn + 1] >> 2) & 0x3F;
type = ctx->buffer[posn + 2] & 0xEF; /* Strip "PF" bit */
/* Dispatch data packets to the appropriate channel */
if (!gsm0710_packet(ctx, channel, type,
ctx->buffer + posn + header_size + 1, len)) {
/* Session has been terminated */
ctx->buffer_used = 0;
return;
}
posn += len + header_size + 2;
} else if (ctx->buffer[posn] == 0x7E) {
/* Advanced format: skip additional 0x7E bytes between frames */
while ((posn + 1) < ctx->buffer_used &&
ctx->buffer[posn + 1] == 0x7E) {
++posn;
}
/* Search for the end of the packet (the next 0x7E byte) */
len = posn + 1;
while (len < ctx->buffer_used &&
ctx->buffer[len] != 0x7E) {
++len;
}
if (len >= ctx->buffer_used) {
/* There are insufficient bytes for a packet at present */
if (posn == 0 && len >= (int)sizeof(ctx->buffer)) {
/* The buffer is full and we were unable to find a
legitimate packet. Discard the buffer and restart */
posn = len;
}
break;
}
/* Undo control byte quoting in the packet */
posn2 = 0;
++posn;
while (posn < len) {
if (ctx->buffer[posn] == 0x7D) {
++posn;
if (posn >= len)
break;
ctx->buffer[posn2++] = (ctx->buffer[posn++] ^ 0x20);
} else {
ctx->buffer[posn2++] = ctx->buffer[posn++];
}
}
/* Validate the checksum on the packet header */
if (posn2 >= 3) {
if (((gsm0710_compute_crc(ctx->buffer, 2) ^
ctx->buffer[posn2 - 1]) & 0xFF) != 0) {
gsm0710_debug(ctx,
"*** GSM 07.10 advanced checksum "
"check failed ***");
continue;
}
} else {
gsm0710_debug(ctx,
"*** GSM 07.10 advanced packet "
"is too small ***");
continue;
}
/* Decode and dispatch the packet */
channel = (ctx->buffer[0] >> 2) & 0x3F;
type = ctx->buffer[1] & 0xEF; /* Strip "PF" bit */
if (!gsm0710_packet(ctx, channel, type,
ctx->buffer + 2, posn2 - 3)) {
/* Session has been terminated */
ctx->buffer_used = 0;
return;
}
} else {
++posn;
}
}
if (posn < ctx->buffer_used) {
memmove(ctx->buffer, ctx->buffer + posn,
ctx->buffer_used - posn);
ctx->buffer_used -= posn;
} else {
ctx->buffer_used = 0;
}
}
/* Write a block of data to the the underlying device. It will be split
into several frames according to the frame size, if necessary */
void gsm0710_write_data(struct gsm0710_context *ctx, int channel,
const void *data, int len)
{
int temp;
while (len > 0) {
temp = len;
if (temp > ctx->frame_size)
temp = ctx->frame_size;
gsm0710_write_frame(ctx, channel, GSM0710_DATA, data, temp);
data = ((const unsigned char *) data) + temp;
len -= temp;
}
}
/* Set the modem status lines on a channel */
void gsm0710_set_status(struct gsm0710_context *ctx, int channel, int status)
{
unsigned char data[4];
data[0] = GSM0710_STATUS_SET;
data[1] = 0x03;
data[2] = ((channel << 2) | 0x03);
data[3] = status;
gsm0710_write_frame(ctx, 0, GSM0710_DATA, data, 4);
}
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