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-rw-r--r--gsm-receiver/src/lib/decoder/gsmstack.c128
-rw-r--r--gsm-receiver/src/lib/decoder/gsmstack.h24
2 files changed, 141 insertions, 11 deletions
diff --git a/gsm-receiver/src/lib/decoder/gsmstack.c b/gsm-receiver/src/lib/decoder/gsmstack.c
index 2bdbf12..3766268 100644
--- a/gsm-receiver/src/lib/decoder/gsmstack.c
+++ b/gsm-receiver/src/lib/decoder/gsmstack.c
@@ -24,17 +24,6 @@
static const int USEFUL_BITS = 142;
-enum BURST_TYPE {
- UNKNOWN,
- FCCH,
- PARTIAL_SCH, //successful correlation, but missing data ^
- SCH,
- CTS_SCH,
- COMPACT_SCH,
- NORMAL,
- DUMMY,
- ACCESS
-};
static void out_gsmdecode(char type, int arfcn, int ts, int fn, char *data, int len);
/* encode a decoded burst (1 bit per byte) into 8-bit-per-byte */
@@ -81,6 +70,123 @@ diff_decode(char *dst, char *src, int len)
}
#endif
+/* TODO: handle mapping in a more elegant way or simplify the function */
+
+uint8_t
+get_chan_type(enum TIMESLOT_TYPE type, int fn, uint8_t *ss)
+{
+ uint8_t chan_type = GSMTAP_CHANNEL_BCCH;
+ *ss = 0;
+ int mf51 = fn % 51;
+
+ if(type == TST_FCCH_SCH_BCCH_CCCH_SDCCH4)
+ {
+ if(mf51 == 22) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4;
+ *ss = 0;
+ }
+ else if(mf51 == 26) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4;
+ *ss = 1;
+ }
+ else if(mf51 == 32) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4;
+ *ss = 2;
+ }
+ else if(mf51 == 36) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4;
+ *ss = 3;
+ }
+ else if(mf51 == 42) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 2 : 0;
+ }
+ else if(mf51 == 46) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH4 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 3 : 1;
+ }
+ }
+ else if(type == TST_FCCH_SCH_BCCH_CCCH)
+ {
+ if(mf51 != 2) /* BCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_CCCH;
+ *ss = 0;
+ }
+ }
+ else if(type == TST_SDCCH8)
+ {
+ if(mf51 == 0) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 0;
+ }
+ else if(mf51 == 4) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 1;
+ }
+ else if(mf51 == 8) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 2;
+ }
+ else if(mf51 == 12) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 3;
+ }
+ else if(mf51 == 16) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 4;
+ }
+ else if(mf51 == 20) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 5;
+ }
+ else if(mf51 == 24) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 6;
+ }
+ else if(mf51 == 28) /* SDCCH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8;
+ *ss = 7;
+ }
+ else if(mf51 == 32) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 4 : 0;
+ }
+ else if(mf51 == 36) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 5 : 1;
+ }
+ else if(mf51 == 40) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 6 : 2;
+ }
+ else if(mf51 == 44) /* SAACH */
+ {
+ chan_type = GSMTAP_CHANNEL_SDCCH8 | GSMTAP_CHANNEL_ACCH;
+ *ss = ((fn % 102) > 51) ? 7 : 3;
+ }
+ }
+
+ return chan_type;
+}
+
/*
* Initialize a new GSMSTACK context.
*/
diff --git a/gsm-receiver/src/lib/decoder/gsmstack.h b/gsm-receiver/src/lib/decoder/gsmstack.h
index 62427d2..ea84d60 100644
--- a/gsm-receiver/src/lib/decoder/gsmstack.h
+++ b/gsm-receiver/src/lib/decoder/gsmstack.h
@@ -9,10 +9,34 @@ extern "C" {
#include <linux/if_ether.h>
#include "interleave.h"
+enum BURST_TYPE {
+ UNKNOWN = 0,
+ FCCH,
+ PARTIAL_SCH, //successful correlation, but missing data ^
+ SCH,
+ CTS_SCH,
+ COMPACT_SCH,
+ NORMAL,
+ DUMMY,
+ ACCESS
+};
+
+enum TIMESLOT_TYPE {
+ TST_UNKNOWN = 0,
+ TST_OFF, /* timeslot is not decoded */
+ TST_FCCH_SCH_BCCH_CCCH_SDCCH4,
+ TST_FCCH_SCH_BCCH_CCCH,
+ TST_SDCCH8,
+ TST_TCHF
+};
+
struct gs_ts_ctx {
/* FIXME: later do this per each ts per each arfcn */
unsigned char burst[4 * 58 * 2];
+ unsigned char burst2[8 * 58 * 2]; /* buffer for FACCH on TCH */
int burst_count;
+ int burst_count2; /* counter for FACCH on TCH */
+ enum TIMESLOT_TYPE type;
};
typedef struct
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