gsmstack: add new unfinished GSM burst/channel demultiplex

This is some unfinished work on a new codebase for 'proper'
demultiplex of all the various physical and logical channel
types.

Basically this includes everything needed to get from the
differential-decoded bursts up to the MAC blocks that can
be passed up to layer 2.

1 files changed, 133 insertions, 0 deletions

diff --git a/gsmstack/gsmstack.h b/gsmstack/gsmstack.h
new file mode 100644
index 0000000..9986dff
--- /dev/null
+++ b/gsmstack/gsmstack.h
@@ -0,0 +1,133 @@
+#ifndef _GSMSTACK_H
+#define _GSMSTACK_H
+
+#define NR_TIMESLOTS	8
+#define NR_ARFCN	1024
+
+#define BURST_BITS	(USEFUL_BITS/8 + 1)
+
+#include "gsmtap.h"
+enum gsm_burst_type {
+	GSM_BURST_UNKNOWN = GSMTAP_BURST_UNKNOWN,
+	GSM_BURST_FCCH = GSMTAP_BURST_FCCH,
+	GSM_BURST_PARTIAL_FCCH = GSMTAP_BURST_PARTIAL_FCCH,
+	GSM_BURST_SCH = GSMTAP_BURST_SCH,
+	GSM_BURST_CTS_SCH = GSMTAP_BURST_CTS_SCH,
+	GSM_BURST_COMPACT_SCH = GSMTAP_BURST_COMPACT_SCH,
+	GSM_BURST_NORMAL = GSMTAP_BURST_NORMAL,
+	GSM_BURST_DUMMY = GSMTAP_BURST_DUMMY,
+	GSM_BURST_ACCESS = GSMTAP_BURST_ACCESS,
+	GSM_BURST_NONE = GSMTAP_BURST_NONE,
+	_GSM_BURST_CNT
+};
+
+
+struct gsm_burst {
+	/* time at which we were received */
+	struct timeval rx_time;
+
+	/* the physical channel which we're part of.
+	 * always guaranteed to be != NULL */
+	struct gsm_phys_chan *phys_chan;
+
+	/* the logical channel to which we belong.
+	 * only filled-in if we actually know about it */
+	struct gsm_logi_chan *logi_chan;
+
+	/* the burst type (as per gsmtap.h) */
+	unsigned char burst_type;
+
+	/* the relative receive TDMA frame */
+	unsigned int rx_frame_nr;
+
+	/* the timeslot number is part of the phys_chan */
+
+	/* the burst after differential decode, 8 bit per byte */
+	unsigned char decoded[BURST_BITS];
+
+	/* the burst after differential decode, 1 bit per byte */
+	unsigned char decoded_bits[USEFUL_BITS];
+};
+
+struct gsm_burst_stats {
+	unsigned int rx_total;
+	unsigned int rx_type[_GSM_BURST_CNT];
+};
+
+enum gsm_logical_channel_type {
+	GSM_LCHAN_UNKNOWN,
+	GSM_LCHAN_NONE,
+
+	/* CBCH */
+	GSM_LCHAN_FCCH,		/* Frequency Correction CH */
+	GSM_LCHAN_SCH,		/* Synchronization CH */
+	GSM_LCHAN_BCCH,		/* Broadcast Control CH */
+	GSM_LCHAN_PCH,		/* Paging CH */
+	GSM_LCHAN_NCH,		/* Notification CH */
+	GSM_LCHAN_AGCH,		/* Access Grant CH */
+	GSM_LCHAN_CBCH,		/* Cell Broadcast CH */
+
+	/* SDCCH */
+	GSM_LCHAN_SDCCH8,	/* Slow Dedicated Control CH */
+	GSM_LCHAN_SACCH8C,	/* Slow Associated Control CH */
+
+	/* TCH */
+	GSM_LCHAN_TCH,		/* Traffic CH */
+	GSM_LCHAN_SACCH,	/* Slow Associated Control CH */
+
+	/* uplink */
+	GSM_LCHAN_RACH,		/* Random Access CH */
+};
+
+struct gsm_logi_chan {
+	enum gsm_logical_channel_type type;
+	/* here we aggregate the bursts for this logical channel
+	 * until we have found enough bursts for one MAC block */
+	struct gsm_burst burst_buf[4];
+	int next_burst;
+
+	struct gsm_burst_stats stats;
+};
+
+enum gsm_phys_chan_config {
+	GSM_PCHAN_UNKNOWN,
+	GSM_PCHAN_CCCH,
+	GSM_PCHAN_CCCH_WITH_SDCCH8,
+	GSM_PCHAN_TCH_F,
+	GSM_PCHAN_TCH_H,
+	GSM_PCHAN_SDCCH8_SACCH8C,
+};
+
+/* maximum logical channels for one physical channel */
+#define NR_LOGI_CHANS	16
+
+/* A GSM physical channel configuration */
+struct gsm_phys_chan {
+	/* in which timeslot is this channel? */
+	unsigned int timeslot;
+	/* to which RF channel do we belong? */
+	struct gsm_rf_chan *rf_chan;
+	/* how is our physical configuration */
+	enum gsm_phys_chan_config config;
+	/* those are our logical channels */
+	struct gsm_logi_chan logi_chan[NR_LOGI_CHANS];
+	int nr_logi_chans;
+
+	struct gsm_burst_stats stats;
+};
+
+struct gsm_rf_chan {
+	/* ARFCN (frequency) of the RF channel */
+	unsigned int arfcn;
+
+	/* current RFN as determined by SCH + frame count */
+	unsigned int rfn;
+
+	/* the physical channel for each timeslot */
+	struct gsm_phys_chan phys_chan[NR_TIMESLOTS];
+};
+
+
+extern struct gsm_rf_chan *gsm_init_rfchan(unsigned int arfcn);
+
+#endif /* _GSMSTACK_H */