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Improve the generic frame acquisition 

* Add CRC-16-IBM supported by CC11xx products
* Check CRC for frame validity
* Extract variable frame length
* Tested with Reaktor-Hello-World in-orbit frame
This commit is contained in:
Manolis Surligas 2018-12-03 01:42:14 +02:00
parent 10f27c045e
commit 4ec333f5e6
12 changed files with 427 additions and 104 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
grc/CMakeLists.txt
View File

@ -52,6 +52,7 @@ list(APPEND enabled_blocks
satnogs_ogg_source.xml
satnogs_noaa_apt_sink.xml
satnogs_whitening.xml
satnogs_frame_acquisition.xml
)
if(${INCLUDE_DEBUG_BLOCKS})

1
grc/satnogs_block_tree.xml
View File

@ -42,4 +42,5 @@
<block>satnogs_ccsds_rs_decoder_mm</block>
<block>satnogs_decoder_8b10b</block>
<block>variable_whitening</block>
<block>satnogs_frame_acquisition</block>
</cat>

119
grc/satnogs_frame_acquisition.xml Normal file
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@ -0,0 +1,119 @@
<?xml version="1.0"?>
<block>
<name>Generic Frame Acquisition</name>
<key>satnogs_frame_acquisition</key>
<import>import satnogs</import>
<make>satnogs.frame_acquisition($variant, $preamble, $preamble_thrsh, $sync_word, $sync_thrsh, $frame_size_field_len, $frame_len, $crc, $whitening, $max_frame_len)</make>
<param>
<name>Variant</name>
<key>variant</key>
<type>enum</type>
<option>
<name>TI, Constant Frame Length</name>
<key>0</key>
</option>
<option>
<name>TI, Variable Frame Length</name>
<key>1</key>
</option>
<option>
<name>Golay24 coded Frame Length</name>
<key>2</key>
</option>
</param>
<param>
<name>Frame Preamble</name>
<key>preamble</key>
<value>[0x55, 0x55, 0x55, 0x55, 0x55]</value>
<type>raw</type>
</param>
<param>
<name>Preamble Threshold</name>
<key>preamble_thrsh</key>
<value>5</value>
<type>int</type>
</param>
<param>
<name>Synchronization Word</name>
<key>sync_word</key>
<value>[0x31, 0xe5]</value>
<type>raw</type>
</param>
<param>
<name>Synchronization Word Threshold</name>
<key>sync_thrsh</key>
<value>3</value>
<type>int</type>
</param>
<param>
<name>Frame Size Field Length</name>
<key>frame_size_field_len</key>
<value>1</value>
<type>int</type>
<hide>>#if $variant() == 1 then 'none' else 'all'#</hide>
</param>
<param>
<name>Frame Length</name>
<key>frame_len</key>
<value>128</value>
<type>int</type>
<hide>>#if $variant() == 0 then 'none' else 'all'#</hide>
</param>
<param>
<name>Maximum Frame Length</name>
<key>max_frame_len</key>
<value>2048</value>
<type>int</type>
</param>
<param>
<name>Whitening</name>
<key>whitening</key>
<value>None</value>
<type>raw</type>
</param>
<param>
<name>CRC</name>
<key>crc</key>
<type>enum</type>
<option>
<name>None</name>
<key>0</key>
</option>
<option>
<name>CRC16_CCITT</name>
<key>1</key>
</option>
<option>
<name>CRC16_CCITT_REVERSED</name>
<key>2</key>
</option>
<option>
<name>CRC16_IBM</name>
<key>3</key>
</option>
<option>
<name>CRC32_CCITT</name>
<key>4</key>
</option>
</param>
<sink>
<name>in</name>
<type>byte</type>
</sink>
<source>
<name>out</name>
<type>message</type>
</source>
</block>

48
include/satnogs/frame_acquisition.h
View File

@ -40,42 +40,32 @@ class SATNOGS_API frame_acquisition : virtual public gr::sync_block
public:
typedef boost::shared_ptr<frame_acquisition> sptr;
typedef enum {
GENERIC_CONSTANT_FRAME_LEN = 0,
GENERIC_VAR_FRAME_LEN,
GOLAY24_CODED_FRAME_LEN
} variant_t;
typedef enum {
CRC_NONE = 0,
CRC16,
CRC16_CCITT,
CRC16_CCITT_REVERSED,
CRC16_IBM,
CRC32
} checksum_t;
static sptr
make_generic_var_len (const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_len = 1,
checksum_t crc = CRC_NONE,
whitening::sptr descrambler = nullptr,
size_t max_frame_len = 2048);
static sptr
make_generic_const_len(const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_len = 1,
checksum_t crc = CRC_NONE,
whitening::sptr descrambler = nullptr,
size_t max_frame_len = 2048);
static sptr
make_golay24_var_len (const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
checksum_t crc = CRC_NONE,
whitening::sptr descrambler = nullptr,
size_t max_frame_len = 2048);
make(variant_t variant,
const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_field_len,
size_t frame_len,
checksum_t crc = CRC_NONE,
whitening::whitening_sptr descrambler = nullptr,
size_t max_frame_len = 2048);
};
} // namespace satnogs

6
include/satnogs/shift_reg.h
View File

@ -23,6 +23,8 @@
#include <satnogs/api.h>
#include <deque>
#include <ostream>
namespace gr
{
namespace satnogs
@ -35,7 +37,7 @@ namespace satnogs
class SATNOGS_API shift_reg
{
public:
shift_reg (size_t len = 32);
shift_reg (size_t len);
~shift_reg ();
void
@ -86,6 +88,8 @@ public:
bool
back();
friend std::ostream&
operator<<(std::ostream& os, const shift_reg& reg);
private:
const size_t d_len;

112
include/satnogs/utils.h
View File

@ -116,6 +116,7 @@ static const uint16_t crc16_ccitt_table[256] =
0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17,
0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 };
static inline uint16_t
update_crc16_ccitt_reversed (uint16_t crc, const uint8_t *data, size_t len)
{
@ -147,6 +148,31 @@ crc16_ccitt (const uint8_t *data, size_t len)
return update_crc16_ccitt (0x0000, data, len);
}
static uint16_t
update_crc16_ibm (uint8_t crc, uint16_t reg)
{
const uint16_t crc_poly = 0x8005;
for (size_t i = 0; i < 8; i++) {
if (((reg & 0x8000) >> 8) ^ (crc & 0x80)) {
reg = (reg << 1) ^ crc_poly;
}
else {
reg = (reg << 1);
}
crc <<= 1;
}
return reg;
}
static uint16_t
crc16_ibm (uint8_t *buf, size_t len)
{
uint16_t crc = 0xFFFF;
for (size_t i = 0; i < len; i++)
crc = update_crc16_ibm (buf[i], crc);
return crc;
}
/**
* Counts the number of active bits in x
*/
@ -216,6 +242,92 @@ reverse_uint64_bytes (uint64_t x)
return x;
}
/**
* CRC-32 calculation using lookup tables, supporting progressive CRC calculation
* polynomial: 0x104C11DB7
*
* @param crc the initial feed
* @param data the buffer containing the data
* @param len the length of the buffer
* @return the CRC-32 result
*/
static inline uint32_t
update_crc32 (uint32_t crc, const uint8_t *data, size_t len)
{
static const uint32_t crc32_lut[256] =
{ 0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL, 0x076DC419L,
0x706AF48FL, 0xE963A535L, 0x9E6495A3L, 0x0EDB8832L, 0x79DCB8A4L,
0xE0D5E91EL, 0x97D2D988L, 0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L,
0x90BF1D91L, 0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL,
0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L, 0x136C9856L,
0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL, 0x14015C4FL, 0x63066CD9L,
0xFA0F3D63L, 0x8D080DF5L, 0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L,
0xA2677172L, 0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL,
0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L, 0x32D86CE3L,
0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L, 0x26D930ACL, 0x51DE003AL,
0xC8D75180L, 0xBFD06116L, 0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L,
0xB8BDA50FL, 0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L,
0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL, 0x76DC4190L,
0x01DB7106L, 0x98D220BCL, 0xEFD5102AL, 0x71B18589L, 0x06B6B51FL,
0x9FBFE4A5L, 0xE8B8D433L, 0x7807C9A2L, 0x0F00F934L, 0x9609A88EL,
0xE10E9818L, 0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L,
0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL, 0x6C0695EDL,
0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L, 0x65B0D9C6L, 0x12B7E950L,
0x8BBEB8EAL, 0xFCB9887CL, 0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L,
0xFBD44C65L, 0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L,
0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL, 0x4369E96AL,
0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L, 0x44042D73L, 0x33031DE5L,
0xAA0A4C5FL, 0xDD0D7CC9L, 0x5005713CL, 0x270241AAL, 0xBE0B1010L,
0xC90C2086L, 0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL,
0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L, 0x59B33D17L,
0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL, 0xEDB88320L, 0x9ABFB3B6L,
0x03B6E20CL, 0x74B1D29AL, 0xEAD54739L, 0x9DD277AFL, 0x04DB2615L,
0x73DC1683L, 0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L,
0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L, 0xF00F9344L,
0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL, 0xF762575DL, 0x806567CBL,
0x196C3671L, 0x6E6B06E7L, 0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL,
0x67DD4ACCL, 0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L,
0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L, 0xD1BB67F1L,
0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL, 0xD80D2BDAL, 0xAF0A1B4CL,
0x36034AF6L, 0x41047A60L, 0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL,
0x4669BE79L, 0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L,
0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL, 0xC5BA3BBEL,
0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L, 0xC2D7FFA7L, 0xB5D0CF31L,
0x2CD99E8BL, 0x5BDEAE1DL, 0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL,
0x026D930AL, 0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L,
0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L, 0x92D28E9BL,
0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L, 0x86D3D2D4L, 0xF1D4E242L,
0x68DDB3F8L, 0x1FDA836EL, 0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L,
0x18B74777L, 0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL,
0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L, 0xA00AE278L,
0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L, 0xA7672661L, 0xD06016F7L,
0x4969474DL, 0x3E6E77DBL, 0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L,
0x37D83BF0L, 0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L,
0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L, 0xBAD03605L,
0xCDD70693L, 0x54DE5729L, 0x23D967BFL, 0xB3667A2EL, 0xC4614AB8L,
0x5D681B02L, 0x2A6F2B94L, 0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL,
0x2D02EF8DL };
register uint32_t i;
for (i = 0; i < len; i++) {
crc = (crc >> 8) ^ crc32_lut[(crc ^ data[i]) & 0xff];
}
return crc;
}
/**
* Calculates the CRC-32 of the buffer buf.
* @param buf The buffer containing the data
* @param len the size of the buffer
* @return the CRC-32 of the buffer
*/
static inline uint32_t
crc32 (const uint8_t *buf, size_t len)
{
unsigned int crc = update_crc32 (0xffffffff, buf, len) ^ 0xffffffff;
return crc;
}
} // namespace satnogs
} // namespace gr

8
include/satnogs/whitening.h
View File

@ -42,13 +42,15 @@ public:
int
unique_id ();
typedef boost::shared_ptr<whitening> sptr;
typedef boost::shared_ptr<whitening> whitening_sptr;
static sptr
static whitening_sptr
make(uint32_t mask, uint32_t seed, uint32_t order);
whitening (uint32_t mask, uint32_t seed, uint32_t order);
~whitening();
void
reset ();
@ -65,7 +67,7 @@ public:
private:
digital::lfsr d_lfsr;
int d_id;
int d_id;
};
} // namespace satnogs

197
lib/frame_acquisition_impl.cc
View File

@ -27,6 +27,9 @@
#include "frame_acquisition_impl.h"
#include <satnogs/golay24.h>
#include <satnogs/log.h>
#include <satnogs/utils.h>
#include <arpa/inet.h>
namespace gr
{
@ -34,53 +37,27 @@ namespace satnogs
{
frame_acquisition::sptr
frame_acquisition::make_generic_var_len (const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_len,
checksum_t crc,
whitening::sptr descrambler,
size_t max_frame_len)
frame_acquisition::make (variant_t variant,
const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_field_len,
size_t frame_len,
checksum_t crc,
whitening::whitening_sptr descrambler,
size_t max_frame_len)
{
return gnuradio::get_initial_sptr (
new frame_acquisition_impl (frame_acquisition_impl::GENERIC_VAR_FRAME_LEN,
new frame_acquisition_impl (variant,
preamble,
preamble_threshold, sync, sync_threshold,
frame_size_len, 0, crc, descrambler,
max_frame_len));
}
frame_acquisition::sptr
frame_acquisition::make_generic_const_len (const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_len, checksum_t crc,
whitening::sptr descrambler,
size_t max_frame_len)
{
return gnuradio::get_initial_sptr (
new frame_acquisition_impl (frame_acquisition_impl::GENERIC_CONSTANT_FRAME_LEN,
preamble,
preamble_threshold, sync, sync_threshold,
0, frame_len, crc, descrambler,
max_frame_len));
}
frame_acquisition::sptr
frame_acquisition::make_golay24_var_len (const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold, checksum_t crc,
whitening::sptr descrambler,
size_t max_frame_len)
{
return gnuradio::get_initial_sptr (
new frame_acquisition_impl (frame_acquisition_impl::GOLAY24_CODED_FRAME_LEN,
preamble,
preamble_threshold, sync, sync_threshold,
0, 0, crc, descrambler,
preamble_threshold,
sync,
sync_threshold,
frame_size_field_len,
frame_len,
crc,
descrambler,
max_frame_len));
}
@ -89,10 +66,10 @@ frame_acquisition_impl::frame_acquisition_impl (variant_t variant,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_len,
size_t frame_size_field_len,
size_t frame_len,
checksum_t crc,
whitening::sptr descrambler,
whitening::whitening_sptr descrambler,
size_t max_frame_len) :
gr::sync_block ("frame_acquisition",
gr::io_signature::make (1, 1, sizeof(uint8_t)),
@ -108,17 +85,17 @@ frame_acquisition_impl::frame_acquisition_impl (variant_t variant,
d_sync_thrsh(sync_threshold),
d_state(SEARCHING),
d_cnt(0),
d_frame_size_field_len(frame_size_len),
d_frame_size_field_len(frame_size_field_len),
d_frame_len(frame_len),
d_max_frame_len(max_frame_len),
d_crc(crc),
d_crc_len(0),
d_whitening(descrambler)
{
set_output_multiple(8);
for(uint8_t b : preamble) {
d_preamble <<= (b >> 7);
d_preamble <<= ((b >> 6) & 0x1);
d_preamble <<= ((b >> 6) & 0x1);
d_preamble <<= ((b >> 5) & 0x1);
d_preamble <<= ((b >> 4) & 0x1);
d_preamble <<= ((b >> 3) & 0x1);
@ -129,7 +106,6 @@ frame_acquisition_impl::frame_acquisition_impl (variant_t variant,
for(uint8_t b : sync) {
d_sync <<= (b >> 7);
d_sync <<= ((b >> 6) & 0x1);
d_sync <<= ((b >> 6) & 0x1);
d_sync <<= ((b >> 5) & 0x1);
d_sync <<= ((b >> 4) & 0x1);
d_sync <<= ((b >> 3) & 0x1);
@ -168,10 +144,33 @@ frame_acquisition_impl::frame_acquisition_impl (variant_t variant,
throw std::invalid_argument ("Frame length field can be up to 4 bytes");
}
if (d_frame_size_field_len == 0) {
if (d_frame_size_field_len == 0 && d_variant != GENERIC_CONSTANT_FRAME_LEN) {
throw std::invalid_argument ("Frame length field cannot be 0");
}
if(d_variant == GENERIC_CONSTANT_FRAME_LEN) {
d_frame_size_field_len = 0;
}
/* Set the CRC length */
switch(d_crc) {
case CRC16_CCITT:
d_crc_len = 2;
break;
case CRC16_CCITT_REVERSED:
d_crc_len = 2;
break;
case CRC16_IBM:
d_crc_len = 2;
break;
case CRC32:
d_crc_len = 4;
break;
default:
d_crc_len = 0;
break;
}
d_pdu = new uint8_t[max_frame_len];
/* Register the PMT message queue */
@ -219,6 +218,7 @@ frame_acquisition_impl::searching_preamble (const uint8_t* in, int len)
d_preamble_shift_reg <<= in[i];
shift_reg tmp = d_preamble_shift_reg ^ d_preamble;
if(tmp.count() <= d_preamble_thrsh) {
LOG_DEBUG("Found PREAMBLE");
d_state = SEARCHING_SYNC;
d_cnt = 0;
return i+1;
@ -235,12 +235,16 @@ frame_acquisition_impl::searching_sync (const uint8_t* in, int len)
shift_reg tmp = d_sync_shift_reg ^ d_sync;
d_cnt++;
if (tmp.count () <= d_sync_thrsh) {
LOG_DEBUG("Found SYNC");
switch(d_variant) {
case GENERIC_CONSTANT_FRAME_LEN:
d_state = DECODING_PAYLOAD;
break;
case GENERIC_VAR_FRAME_LEN:
d_state = DECODING_GENERIC_FRAME_LEN;
break;
case GENERIC_CONSTANT_FRAME_LEN:
d_state = DECODING_GENERIC_FRAME_LEN;
case GOLAY24_CODED_FRAME_LEN:
d_state = DECODING_GOLAY24_FRAME_LEN;
break;
}
d_cnt = 0;
@ -274,15 +278,28 @@ frame_acquisition_impl::dec_generic_frame_len (const uint8_t* in, int len)
d_frame_len |= b;
d_cnt++;
if(d_cnt == d_frame_size_field_len) {
/* Most of the available modems apply whitening on the frame length too */
if(d_whitening) {
uint32_t descrambled = 0x0;
d_whitening->descramble((uint8_t *)&descrambled,
(const uint8_t *)&d_frame_len,
d_frame_size_field_len, true);
d_frame_size_field_len, false);
d_frame_len = descrambled;
}
/* Mask the bits that are not used */
d_frame_len &= ~(0xFFFFFFFF << (d_frame_size_field_len * 8));
LOG_DEBUG("Found frame length: %u", d_frame_len);
/* Length field is needed for the CRC calculation */
for(uint32_t j = 0; j < d_frame_size_field_len; j++) {
d_pdu[j] = (d_frame_len >> ((d_frame_size_field_len - 1 - j) * 8)) & 0xFF;
}
d_frame_len += d_frame_size_field_len;
/* Append the CRC length if any */
d_frame_len += d_crc_len;
if(d_frame_len < d_max_frame_len) {
d_state = DECODING_PAYLOAD;
}
@ -290,7 +307,7 @@ frame_acquisition_impl::dec_generic_frame_len (const uint8_t* in, int len)
reset();
return (i + 1) * 8;
}
d_cnt = 0;
d_cnt = d_frame_size_field_len;
return (i + 1) * 8;
}
}
@ -321,13 +338,17 @@ frame_acquisition_impl::dec_golay24_frame_len (const uint8_t* in, int len)
if(d_whitening) {
uint32_t descrambled = 0x0;
d_whitening->descramble((uint8_t *)&descrambled,
(const uint8_t *)&d_frame_len, 3, true);
(const uint8_t *)&d_frame_len, 3, false);
d_frame_len = descrambled;
}
golay24 g = golay24 ();
uint16_t tmp = 0;
if (g.decode24 (&tmp, d_frame_len)) {
d_frame_len = tmp;
/* Append the CRC length if any */
d_frame_len += d_crc_len;
/* Check if the payload can fit in the buffer */
if(d_frame_len > d_max_frame_len) {
reset();
@ -354,7 +375,7 @@ frame_acquisition_impl::decoding (const uint8_t* in, int len)
const int s = len / 8;
for(int i = 0; i < s; i++) {
uint8_t b = 0x0;
b |= in[i * 8] << 7;
b = in[i * 8] << 7;
b |= in[i * 8 + 1] << 6;
b |= in[i * 8 + 2] << 5;
b |= in[i * 8 + 3] << 4;
@ -365,9 +386,17 @@ frame_acquisition_impl::decoding (const uint8_t* in, int len)
d_pdu[d_cnt++] = b;
if(d_cnt == d_frame_len) {
if(d_whitening) {
d_whitening->descramble(d_pdu, d_pdu, d_frame_len, true);
d_whitening->descramble(d_pdu + d_frame_size_field_len,
d_pdu + d_frame_size_field_len,
d_frame_len - d_frame_size_field_len, false);
}
if (check_crc ()) {
message_port_pub (
pmt::mp ("out"),
pmt::make_blob (d_pdu + d_frame_size_field_len,
d_frame_len - d_crc_len - d_frame_size_field_len));
}
/* TODO */
reset();
return (i+1) * 8;
}
@ -387,6 +416,56 @@ frame_acquisition_impl::reset ()
d_sync_shift_reg.reset();
}
bool
frame_acquisition_impl::check_crc ()
{
uint16_t crc16_c;
uint16_t crc16_received;
uint32_t crc32_c;
uint32_t crc32_received;
switch(d_crc){
case CRC_NONE:
return true;
case CRC16_CCITT:
crc16_c = crc16_ccitt(d_pdu, d_frame_len - 2);
memcpy(&crc16_received, d_pdu + d_frame_len - 2, 2);
crc16_received = ntohs(crc16_received);
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
if(crc16_c == crc16_received) {
return true;
}
return false;
case CRC16_CCITT_REVERSED:
crc16_c = crc16_ccitt_reversed(d_pdu, d_frame_len - 2);
memcpy(&crc16_received, d_pdu + d_frame_len - 2, 2);
crc16_received = ntohs(crc16_received);
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
if(crc16_c == crc16_received) {
return true;
}
return false;
case CRC16_IBM:
crc16_c = crc16_ibm(d_pdu, d_frame_len - 2);
memcpy(&crc16_received, d_pdu + d_frame_len - 2, 2);
crc16_received = ntohs(crc16_received);
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
if(crc16_c == crc16_received) {
return true;
}
return false;
case CRC32:
crc32_c = crc32(d_pdu, d_frame_len - 4);
memcpy(&crc32_received, d_pdu + d_frame_len - 4, 4);
crc32_received = ntohl(crc32_received);
if(crc32_c == crc32_received) {
return true;
}
return false;
default:
return false;
}
}
} /* namespace satnogs */
} /* namespace gr */

18
lib/frame_acquisition_impl.h
View File

@ -33,21 +33,15 @@ class frame_acquisition_impl : public frame_acquisition
{
public:
typedef enum {
GENERIC_VAR_FRAME_LEN = 0,
GENERIC_CONSTANT_FRAME_LEN,
GOLAY24_CODED_FRAME_LEN
} variant_t;
frame_acquisition_impl (variant_t variant,
const std::vector<uint8_t>& preamble,
size_t preamble_threshold,
const std::vector<uint8_t>& sync,
size_t sync_threshold,
size_t frame_size_len,
size_t frame_size_field_len,
size_t frame_len,
checksum_t crc,
whitening::sptr descrambler,
whitening::whitening_sptr descrambler,
size_t max_frame_len);
~frame_acquisition_impl ();
@ -81,11 +75,12 @@ private:
const size_t d_sync_thrsh;
decoding_state_t d_state;
uint32_t d_cnt;
const uint32_t d_frame_size_field_len;
uint32_t d_frame_size_field_len;
uint32_t d_frame_len;
const uint32_t d_max_frame_len;
const checksum_t d_crc;
whitening::sptr d_whitening;
uint32_t d_crc_len;
whitening::whitening_sptr d_whitening;
uint8_t *d_pdu;
@ -105,6 +100,9 @@ private:
void
reset();
bool
check_crc();
};
} // namespace satnogs

9
lib/shift_reg.cc
View File

@ -199,6 +199,15 @@ shift_reg::back ()
return d_reg.back();
}
std::ostream&
operator<<(std::ostream& os, const shift_reg& reg)
{
for(bool bit : reg.d_reg) {
os << " " << bit;
}
return os;
}
} /* namespace satnogs */
} /* namespace gr */

8
lib/whitening.cc
View File

@ -41,10 +41,10 @@ int whitening::base_unique_id = 1;
* @param order the order of the shift register. This is equal to the
* number of memory stages.
*/
whitening::sptr
whitening::whitening_sptr
whitening::make (uint32_t mask, uint32_t seed, uint32_t order)
{
return whitening::sptr(new whitening(mask, seed, order));
return whitening::whitening_sptr(new whitening(mask, seed, order));
}
@ -62,6 +62,10 @@ whitening::whitening (uint32_t mask, uint32_t seed, uint32_t order) :
d_id = base_unique_id++;
}
whitening::~whitening ()
{
}
int
whitening::unique_id ()
{

4
swig/satnogs_swig0.i
View File

@ -8,6 +8,10 @@
//load generated python docstrings
%include "satnogs_swig0_doc.i"
%template(whitening_sptr) boost::shared_ptr<gr::satnogs::whitening>;
%{
#include "satnogs/morse_tree.h"
#include "satnogs/morse_decoder.h"