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Complete the EON Steel HDLC encoding/decoding work

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The previous patch did the HDLC encoding on packet send, this does the
HDLC decoding on the receive side.

In order to properly check the data integrity, the HDLC-encoded packet
needs to be fully received before it can be processed.  So while the HID
downloading continues to work packet-by-packet, the HDLC encoded BLE
GATT stream needs a temporary buffer for the data that gets filled as we
ask for the reply header.

Right now only the old USB HID path is actually tested, because I
haven't flushed out the packet receiving side in subsurface yet.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2017-06-23 15:05:42 -07:00
parent c863db02f0
commit ca115b97e2
1 changed files with 126 additions and 6 deletions
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132
src/suunto_eonsteel.c
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@ -126,11 +126,10 @@ static void put_le32(unsigned int val, unsigned char *p)
* The maximum payload is 62 bytes.
*/
#define PACKET_SIZE 64
static int receive_packet(suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
static int receive_usbhid_packet(dc_custom_io_t *io, suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
{
unsigned char buf[64];
dc_status_t rc = DC_STATUS_SUCCESS;
dc_custom_io_t *io = _dc_context_custom_io(eon->base.context);
size_t transferred = 0;
int len;
@ -161,6 +160,123 @@ static int receive_packet(suunto_eonsteel_device_t *eon, unsigned char *buffer,
return len;
}
static int fill_ble_buffer(dc_custom_io_t *io, suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
{
int state = 0;
int bytes = 0;
unsigned int crc;
for (;;) {
unsigned char packet[32];
dc_status_t rc = DC_STATUS_SUCCESS;
size_t transferred = 0;
int i;
rc = io->packet_read(io, packet, sizeof(packet), &transferred);
if (rc != DC_STATUS_SUCCESS) {
ERROR(eon->base.context, "BLE GATT read transfer failed");
return -1;
}
for (i = 0; i < transferred; i++) {
unsigned char c = packet[i];
if (c == 0x7e) {
if (state == 1)
goto done;
if (state == 2) {
ERROR(eon->base.context, "BLE GATT stream has escaped 7e character");
return -1;
}
/* Initial 7e character - good */
state = 1;
continue;
}
if (!state) {
ERROR(eon->base.context, "BLE GATT stream did not start with 7e");
return -1;
}
if (c == 0x7d) {
if (state == 2) {
ERROR(eon->base.context, "BLE GATT stream has escaped 7d character");
return -1;
}
state = 2;
continue;
}
if (state == 2) {
c ^= 0x20;
state = 1;
}
if (bytes < size)
buffer[bytes] = c;
bytes++;
}
}
done:
if (bytes < 4) {
ERROR(eon->base.context, "did not receive BLE CRC32 data");
return -1;
}
if (bytes > size) {
ERROR(eon->base.context, "BLE GATT stream too long (%d bytes, buffer is %d)", bytes, size);
return -1;
}
/* Remove and check CRC */
bytes -= 4;
crc = crc32(0, buffer, bytes);
if (crc != array_uint32_le(buffer + bytes)) {
ERROR(eon->base.context, "incorrect BLE CRC32 data");
return -1;
}
HEXDUMP (eon->base.context, DC_LOGLEVEL_DEBUG, "rcv", buffer, bytes);
return bytes;
}
#define HDRSIZE 12
#define MAXDATA 2048
#define CRCSIZE 4
static struct {
unsigned int len, offset;
unsigned char buffer[HDRSIZE + MAXDATA + CRCSIZE];
} ble_data;
static void fill_ble_data(dc_custom_io_t *io, suunto_eonsteel_device_t *eon)
{
int received;
received = fill_ble_buffer(io, eon, ble_data.buffer, sizeof(ble_data.buffer));
if (received < 0)
received = 0;
ble_data.offset = 0;
ble_data.len = received;
}
static int receive_ble_packet(dc_custom_io_t *io, suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
{
int maxsize;
if (ble_data.offset >= ble_data.len)
return 0;
maxsize = ble_data.len - ble_data.offset;
if (size > maxsize)
size = maxsize;
memcpy(buffer, ble_data.buffer + ble_data.offset, size);
ble_data.offset += size;
return size;
}
static int receive_packet(dc_custom_io_t *io, suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
{
if (io->packet_size < 64)
return receive_ble_packet(io, eon, buffer, size);
return receive_usbhid_packet(io, eon, buffer, size);
}
static int add_hdlc(unsigned char *dst, unsigned char val)
{
int chars = 1;
@ -281,8 +397,11 @@ static int receive_header(suunto_eonsteel_device_t *eon, struct eon_hdr *hdr, un
{
int ret;
unsigned char header[64];
dc_custom_io_t *io = _dc_context_custom_io(eon->base.context);
ret = receive_packet(eon, header, sizeof(header));
if (io->packet_size < 64)
fill_ble_data(io, eon);
ret = receive_packet(io, eon, header, sizeof(header));
if (ret < 0)
return -1;
if (ret < 12) {
@ -308,11 +427,12 @@ static int receive_header(suunto_eonsteel_device_t *eon, struct eon_hdr *hdr, un
static int receive_data(suunto_eonsteel_device_t *eon, unsigned char *buffer, int size)
{
int ret = 0;
dc_custom_io_t *io = _dc_context_custom_io(eon->base.context);
while (size > 0) {
int len;
len = receive_packet(eon, buffer + ret, size);
len = receive_packet(io, eon, buffer + ret, size);
if (len < 0)
return -1;
@ -497,7 +617,7 @@ static struct directory_entry *parse_dirent(suunto_eonsteel_device_t *eon, int n
struct directory_entry *entry;
if (namelen + 8 + 1 > len || name[namelen] != 0) {
ERROR(eon->base.context, "corrupt dirent entry");
ERROR(eon->base.context, "corrupt dirent entry: len=%d namelen=%d name='%s'", len, namelen, name);
break;
}
HEXDUMP(eon->base.context, DC_LOGLEVEL_DEBUG, "dir entry", p, 8);
@ -630,7 +750,7 @@ suunto_eonsteel_device_open(dc_device_t **out, dc_context_t *context, const char
return DC_STATUS_SUCCESS;
error_close:
io->packet_close(io);
suunto_eonsteel_device_close((dc_device_t *) eon);
error_free:
free(eon);
return status;