{trxcon,virt_phy}: shared GPRS L1 (MAC) implementation

Change-Id: I9567d64f9d00262e36147e8d7e541e5e246bda5f
Related: OS#5500

24 files changed, 738 insertions, 254 deletions

diff --git a/src/host/trxcon/include/osmocom/bb/Makefile.am b/src/host/trxcon/include/osmocom/bb/Makefile.am
index 127a2c78..4a575ffb 100644
--- a/src/host/trxcon/include/osmocom/bb/Makefile.am
+++ b/src/host/trxcon/include/osmocom/bb/Makefile.am
@@ -5,4 +5,5 @@ SUBDIRS = \
 
 noinst_HEADERS = \
 	l1ctl_proto.h \
+	l1gprs.h \
 	$(NULL)
diff --git a/src/host/trxcon/include/osmocom/bb/l1gprs.h b/src/host/trxcon/include/osmocom/bb/l1gprs.h
new file mode 120000
index 00000000..3bf85176
--- /dev/null
+++ b/src/host/trxcon/include/osmocom/bb/l1gprs.h
@@ -0,0 +1 @@
+../../../../../../include/l1gprs.h
\ No newline at end of file
diff --git a/src/host/trxcon/include/osmocom/bb/trxcon/logging.h b/src/host/trxcon/include/osmocom/bb/trxcon/logging.h
index f8521a0e..ce149926 100644
--- a/src/host/trxcon/include/osmocom/bb/trxcon/logging.h
+++ b/src/host/trxcon/include/osmocom/bb/trxcon/logging.h
@@ -10,6 +10,7 @@ enum {
 	DTRXD,
 	DSCH,
 	DSCHD,
+	DGPRS,
 };
 
 int trxcon_logging_init(void *tall_ctx, const char *category_mask);
diff --git a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h
index 15e63f71..1d012de2 100644
--- a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h
+++ b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h
@@ -4,6 +4,7 @@
 
 struct osmo_fsm_inst;
 struct l1sched_state;
+struct l1gprs_state;
 struct msgb;
 
 struct trxcon_inst {
@@ -18,6 +19,9 @@ struct trxcon_inst {
 
 	/* The L1 scheduler */
 	struct l1sched_state *sched;
+	/* GPRS state (MAC layer) */
+	struct l1gprs_state *gprs;
+
 	/* PHY interface (e.g. TRXC/TRXD) */
 	void *phyif;
 	/* L2 interface (e.g. L1CTL) */
@@ -46,6 +50,7 @@ enum trxcon_log_cat {
 	TRXCON_LOGC_L1D,	/* L1CTL data */
 	TRXCON_LOGC_SCHC,	/* l1sched control */
 	TRXCON_LOGC_SCHD,	/* l1sched data */
+	TRXCON_LOGC_GPRS,	/* l1gprs logging */
 };
 
 void trxcon_set_log_cfg(const int *logc, unsigned int logc_num);
diff --git a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon_fsm.h b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon_fsm.h
index 49b5e3a5..bbb4eb57 100644
--- a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon_fsm.h
+++ b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon_fsm.h
@@ -37,6 +37,9 @@ enum trxcon_fsm_events {
 	TRXCON_EV_TX_DATA_CNF,
 	TRXCON_EV_RX_DATA_IND,
 	TRXCON_EV_CRYPTO_REQ,
+	TRXCON_EV_GPRS_UL_TBF_CFG_REQ,		/* param: L1CTL msgb */
+	TRXCON_EV_GPRS_DL_TBF_CFG_REQ,		/* param: L1CTL msgb */
+	TRXCON_EV_GPRS_UL_BLOCK_REQ,		/* param: L1CTL msgb */
 };
 
 /* param of TRXCON_EV_FULL_POWER_SCAN_REQ */
diff --git a/src/host/trxcon/src/Makefile.am b/src/host/trxcon/src/Makefile.am
index a286f2ae..c96949a2 100644
--- a/src/host/trxcon/src/Makefile.am
+++ b/src/host/trxcon/src/Makefile.am
@@ -29,6 +29,13 @@ libl1sched_la_SOURCES = \
 	$(NULL)
 
 
+noinst_LTLIBRARIES += libl1gprs.la
+
+libl1gprs_la_SOURCES = \
+	l1gprs.c \
+	$(NULL)
+
+
 noinst_LTLIBRARIES += libtrxcon.la
 
 libtrxcon_la_SOURCES = \
@@ -51,6 +58,7 @@ trxcon_SOURCES = \
 trxcon_LDADD = \
 	libtrxcon.la \
 	libl1sched.la \
+	libl1gprs.la \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOCODING_LIBS) \
 	$(LIBOSMOGSM_LIBS) \
diff --git a/src/host/trxcon/src/l1ctl.c b/src/host/trxcon/src/l1ctl.c
index ec98f82b..a45bc2c4 100644
--- a/src/host/trxcon/src/l1ctl.c
+++ b/src/host/trxcon/src/l1ctl.c
@@ -785,6 +785,7 @@ static int l1ctl_rx_crypto_req(struct trxcon_inst *trxcon, struct msgb *msg)
 int trxcon_l1ctl_receive(struct trxcon_inst *trxcon, struct msgb *msg)
 {
 	const struct l1ctl_hdr *l1h;
+	int rc;
 
 	l1h = (const struct l1ctl_hdr *)msg->l1h;
 	msg->l1h = (uint8_t *)l1h->data;
@@ -818,11 +819,20 @@ int trxcon_l1ctl_receive(struct trxcon_inst *trxcon, struct msgb *msg)
 		return l1ctl_rx_tch_mode_req(trxcon, msg);
 	case L1CTL_CRYPTO_REQ:
 		return l1ctl_rx_crypto_req(trxcon, msg);
-
+	case L1CTL_GPRS_UL_TBF_CFG_REQ:
+		rc = osmo_fsm_inst_dispatch(trxcon->fi, TRXCON_EV_GPRS_UL_TBF_CFG_REQ, msg);
+		msgb_free(msg);
+		return rc;
+	case L1CTL_GPRS_DL_TBF_CFG_REQ:
+		rc = osmo_fsm_inst_dispatch(trxcon->fi, TRXCON_EV_GPRS_DL_TBF_CFG_REQ, msg);
+		msgb_free(msg);
+		return rc;
+	case L1CTL_GPRS_UL_BLOCK_REQ:
+		rc = osmo_fsm_inst_dispatch(trxcon->fi, TRXCON_EV_GPRS_UL_BLOCK_REQ, msg);
+		msgb_free(msg);
+		return rc;
 	/* Not (yet) handled messages */
 	case L1CTL_NEIGH_PM_REQ:
-	case L1CTL_DATA_TBF_REQ:
-	case L1CTL_TBF_CFG_REQ:
 	case L1CTL_DM_FREQ_REQ:
 	case L1CTL_SIM_REQ:
 		LOGPFSMSL(trxcon->fi, g_logc_l1c, LOGL_NOTICE,
diff --git a/src/host/trxcon/src/l1gprs.c b/src/host/trxcon/src/l1gprs.c
new file mode 120000
index 00000000..0185f68b
--- /dev/null
+++ b/src/host/trxcon/src/l1gprs.c
@@ -0,0 +1 @@
+../../../shared/l1gprs.c
\ No newline at end of file
diff --git a/src/host/trxcon/src/logging.c b/src/host/trxcon/src/logging.c
index 2222577b..e94ad2d8 100644
--- a/src/host/trxcon/src/logging.c
+++ b/src/host/trxcon/src/logging.c
@@ -67,6 +67,12 @@ static struct log_info_cat trxcon_log_info_cat[] = {
 		.color = "\033[1;36m",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
+	[DGPRS] = {
+		.name = "DGPRS",
+		.description = "L1 GPRS (MAC layer)",
+		.color = "\033[1;36m",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
 };
 
 static const struct log_info trxcon_log_info = {
@@ -80,6 +86,7 @@ static const int trxcon_log_cfg[] = {
 	[TRXCON_LOGC_L1D] = DL1D,
 	[TRXCON_LOGC_SCHC] = DSCH,
 	[TRXCON_LOGC_SCHD] = DSCHD,
+	[TRXCON_LOGC_GPRS] = DGPRS,
 };
 
 int trxcon_logging_init(void *tall_ctx, const char *category_mask)
diff --git a/src/host/trxcon/src/trxcon_fsm.c b/src/host/trxcon/src/trxcon_fsm.c
index 186c04bc..053ca2f6 100644
--- a/src/host/trxcon/src/trxcon_fsm.c
+++ b/src/host/trxcon/src/trxcon_fsm.c
@@ -2,7 +2,7 @@
  * OsmocomBB <-> SDR connection bridge
  * The trxcon state machine (see 3GPP TS 44.004, section 5.1)
  *
- * (C) 2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * (C) 2022-2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
  * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
  *
  * All Rights Reserved
@@ -29,12 +29,14 @@
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/gsm/gsm0502.h>
+#include <osmocom/gsm/protocol/gsm_08_58.h>
 
 #include <osmocom/bb/trxcon/trxcon.h>
 #include <osmocom/bb/trxcon/trxcon_fsm.h>
 #include <osmocom/bb/trxcon/phyif.h>
 #include <osmocom/bb/trxcon/l1ctl.h>
 #include <osmocom/bb/l1sched/l1sched.h>
+#include <osmocom/bb/l1gprs.h>
 
 #define S(x)	(1 << (x))
 
@@ -505,6 +507,25 @@ static void trxcon_st_dedicated_action(struct osmo_fsm_inst *fi,
 	}
 }
 
+static void trxcon_st_packet_data_onenter(struct osmo_fsm_inst *fi,
+					  uint32_t prev_state)
+{
+	struct trxcon_inst *trxcon = fi->priv;
+
+	OSMO_ASSERT(trxcon->gprs == NULL);
+	trxcon->gprs = l1gprs_state_alloc(trxcon, trxcon->log_prefix, trxcon);
+	OSMO_ASSERT(trxcon->gprs != NULL);
+}
+
+static void trxcon_st_packet_data_onleave(struct osmo_fsm_inst *fi,
+					  uint32_t next_state)
+{
+	struct trxcon_inst *trxcon = fi->priv;
+
+	l1gprs_state_free(trxcon->gprs);
+	trxcon->gprs = NULL;
+}
+
 static void trxcon_st_packet_data_action(struct osmo_fsm_inst *fi,
 					 uint32_t event, void *data)
 {
@@ -517,14 +538,58 @@ static void trxcon_st_packet_data_action(struct osmo_fsm_inst *fi,
 	case TRXCON_EV_TX_ACCESS_BURST_CNF:
 		l1ctl_tx_rach_conf(trxcon, (const struct trxcon_param_tx_access_burst_cnf *)data);
 		break;
+	case TRXCON_EV_GPRS_UL_TBF_CFG_REQ:
+		l1gprs_handle_ul_tbf_cfg_req(trxcon->gprs, (struct msgb *)data);
+		break;
+	case TRXCON_EV_GPRS_DL_TBF_CFG_REQ:
+		l1gprs_handle_dl_tbf_cfg_req(trxcon->gprs, (struct msgb *)data);
+		break;
+	case TRXCON_EV_GPRS_UL_BLOCK_REQ:
+	{
+		struct l1gprs_prim_ul_block_req block_req;
+		const struct msgb *msg = data;
+		struct l1sched_ts_prim *prim;
+
+		if (l1gprs_handle_ul_block_req(trxcon->gprs, &block_req, msg) != 0)
+			return;
+
+		prim = l1sched_prim_push(trxcon->sched, L1SCHED_PRIM_DATA,
+					 RSL_CHAN_OSMO_PDCH | block_req.hdr.tn, 0x00,
+					 block_req.data, block_req.data_len);
+		if (prim == NULL) {
+			LOGPFSML(fi, LOGL_ERROR, "Failed to enqueue a prim\n");
+			return;
+		}
+		break;
+	}
 	case TRXCON_EV_RX_DATA_IND:
 	{
 		const struct trxcon_param_rx_data_ind *ind = data;
+		struct l1gprs_prim_dl_block_ind block_ind;
+		struct msgb *msg;
 
-		if (ind->link_id == 0x00)
-			LOGPFSML(fi, LOGL_NOTICE, "Rx PDTCH/D message\n");
+		block_ind = (struct l1gprs_prim_dl_block_ind) {
+			.hdr = {
+				.fn = ind->frame_nr,
+				.tn = ind->chan_nr & 0x07,
+			},
+			.meas = {
+				/* .ber10k is set below */
+				.ci_cb = 180, /* 18 dB */
+				.rx_lev = dbm2rxlev(ind->rssi),
+			},
+			.data_len = ind->data_len,
+			.data = ind->data,
+		};
+
+		if (ind->n_bits_total == 0)
+			block_ind.meas.ber10k = 10000;
 		else
-			LOGPFSML(fi, LOGL_NOTICE, "Rx PTCCH/D message\n");
+			block_ind.meas.ber10k = 10000 * ind->n_errors / ind->n_bits_total;
+
+		msg = l1gprs_handle_dl_block_ind(trxcon->gprs, &block_ind);
+		if (msg != NULL)
+			trxcon_l1ctl_send(trxcon, msg);
 		break;
 	}
 	case TRXCON_EV_DCH_EST_REQ:
@@ -550,6 +615,9 @@ static void trxcon_fsm_pre_term_cb(struct osmo_fsm_inst *fi,
 	/* Shutdown the scheduler */
 	if (trxcon->sched != NULL)
 		l1sched_free(trxcon->sched);
+	/* Clean up GPRS L1 state */
+	l1gprs_state_free(trxcon->gprs);
+
 	/* Close active connections */
 	if (trxcon->l2if != NULL)
 		trxcon_l1ctl_close(trxcon);
@@ -625,7 +693,12 @@ static const struct osmo_fsm_state trxcon_fsm_states[] = {
 				| S(TRXCON_EV_DCH_EST_REQ)
 				| S(TRXCON_EV_TX_ACCESS_BURST_REQ)
 				| S(TRXCON_EV_TX_ACCESS_BURST_CNF)
+				| S(TRXCON_EV_GPRS_UL_TBF_CFG_REQ)
+				| S(TRXCON_EV_GPRS_DL_TBF_CFG_REQ)
+				| S(TRXCON_EV_GPRS_UL_BLOCK_REQ)
 				| S(TRXCON_EV_RX_DATA_IND),
+		.onenter = &trxcon_st_packet_data_onenter,
+		.onleave = &trxcon_st_packet_data_onleave,
 		.action = &trxcon_st_packet_data_action,
 	},
 };
@@ -651,6 +724,9 @@ static const struct value_string trxcon_fsm_event_names[] = {
 	OSMO_VALUE_STRING(TRXCON_EV_TX_DATA_CNF),
 	OSMO_VALUE_STRING(TRXCON_EV_RX_DATA_IND),
 	OSMO_VALUE_STRING(TRXCON_EV_CRYPTO_REQ),
+	OSMO_VALUE_STRING(TRXCON_EV_GPRS_UL_TBF_CFG_REQ),
+	OSMO_VALUE_STRING(TRXCON_EV_GPRS_DL_TBF_CFG_REQ),
+	OSMO_VALUE_STRING(TRXCON_EV_GPRS_UL_BLOCK_REQ),
 	{ 0, NULL }
 };
 
diff --git a/src/host/trxcon/src/trxcon_inst.c b/src/host/trxcon/src/trxcon_inst.c
index da4d6180..65e63b3a 100644
--- a/src/host/trxcon/src/trxcon_inst.c
+++ b/src/host/trxcon/src/trxcon_inst.c
@@ -27,6 +27,7 @@
 #include <osmocom/bb/trxcon/trxcon_fsm.h>
 #include <osmocom/bb/l1sched/l1sched.h>
 #include <osmocom/bb/l1sched/logging.h>
+#include <osmocom/bb/l1gprs.h>
 
 extern int g_logc_l1c;
 extern int g_logc_l1d;
@@ -53,6 +54,9 @@ void trxcon_set_log_cfg(const int *logc, unsigned int logc_num)
 		case TRXCON_LOGC_SCHD:
 			schd = logc[i];
 			break;
+		case TRXCON_LOGC_GPRS:
+			l1gprs_logging_init(logc[i]);
+			break;
 		}
 	}
 
diff --git a/src/host/virt_phy/include/osmocom/bb/Makefile.am b/src/host/virt_phy/include/osmocom/bb/Makefile.am
index c52fb937..9a4b939a 100644
--- a/src/host/virt_phy/include/osmocom/bb/Makefile.am
+++ b/src/host/virt_phy/include/osmocom/bb/Makefile.am
@@ -4,4 +4,5 @@ SUBDIRS = \
 
 noinst_HEADERS = \
 	l1ctl_proto.h \
+	l1gprs.h \
 	$(NULL)
diff --git a/src/host/virt_phy/include/osmocom/bb/l1gprs.h b/src/host/virt_phy/include/osmocom/bb/l1gprs.h
new file mode 120000
index 00000000..3bf85176
--- /dev/null
+++ b/src/host/virt_phy/include/osmocom/bb/l1gprs.h
@@ -0,0 +1 @@
+../../../../../../include/l1gprs.h
\ No newline at end of file
diff --git a/src/host/virt_phy/include/osmocom/bb/virtphy/l1ctl_sap.h b/src/host/virt_phy/include/osmocom/bb/virtphy/l1ctl_sap.h
index 724d238b..e756c140 100644
--- a/src/host/virt_phy/include/osmocom/bb/virtphy/l1ctl_sap.h
+++ b/src/host/virt_phy/include/osmocom/bb/virtphy/l1ctl_sap.h
@@ -57,6 +57,8 @@ void l1ctl_rx_tch_mode_req(struct l1_model_ms *ms, struct msgb *msg);
 void l1ctl_rx_neigh_pm_req(struct l1_model_ms *ms, struct msgb *msg);
 void l1ctl_rx_traffic_req(struct l1_model_ms *ms, struct msgb *msg);
 void l1ctl_rx_sim_req(struct l1_model_ms *ms, struct msgb *msg);
+void l1ctl_rx_gprs_uldl_tbf_cfg_req(struct l1_model_ms *ms, struct msgb *msg);
+void l1ctl_rx_gprs_ul_block_req(struct l1_model_ms *ms, struct msgb *msg);
 
 /* transmit routines */
 void l1ctl_tx_reset(struct l1_model_ms *ms, uint8_t msg_type, uint8_t reset_type);
@@ -75,6 +77,8 @@ void l1ctl_tx_pm_conf(struct l1_model_ms *ms, struct l1ctl_pm_req *pm_req);
 void l1ctl_tx_fbsb_conf(struct l1_model_ms *ms, uint8_t res, uint16_t arfcn);
 void l1ctl_tx_ccch_mode_conf(struct l1_model_ms *ms, uint8_t ccch_mode);
 void l1ctl_tx_tch_mode_conf(struct l1_model_ms *ms, uint8_t tch_mode, uint8_t audio_mode);
+void l1ctl_tx_gprs_dl_block_ind(struct l1_model_ms *ms, const struct msgb *msg,
+				uint32_t fn, uint8_t tn, uint8_t rxlev);
 
 /* scheduler functions */
 uint32_t sched_fn_ul(struct gsm_time cur_time, uint8_t chan_nr,
diff --git a/src/host/virt_phy/include/osmocom/bb/virtphy/logging.h b/src/host/virt_phy/include/osmocom/bb/virtphy/logging.h
index b22db992..48f7ed55 100644
--- a/src/host/virt_phy/include/osmocom/bb/virtphy/logging.h
+++ b/src/host/virt_phy/include/osmocom/bb/virtphy/logging.h
@@ -7,6 +7,7 @@ enum virtphy_log_cat {
 	DL1C,
 	DL1P,
 	DVIRPHY,
+	DGPRS,
 	DMAIN
 };
 
diff --git a/src/host/virt_phy/include/osmocom/bb/virtphy/virt_l1_model.h b/src/host/virt_phy/include/osmocom/bb/virtphy/virt_l1_model.h
index b729c443..94581f61 100644
--- a/src/host/virt_phy/include/osmocom/bb/virtphy/virt_l1_model.h
+++ b/src/host/virt_phy/include/osmocom/bb/virtphy/virt_l1_model.h
@@ -16,7 +16,6 @@ enum ms_state {
 	MS_STATE_IDLE_SYNCING,
 	MS_STATE_IDLE_CAMPING,
 	MS_STATE_DEDICATED,
-	MS_STATE_TBF
 };
 
 
@@ -77,15 +76,6 @@ struct l1_state_ms {
 		uint8_t tsc; // training sequence code (unused in virtual um)
 		uint8_t h; // hopping enabled flag (unused in virtual um)
 	} dedicated;
-	struct {
-		struct {
-			uint8_t usf[8];
-			struct llist_head tx_queue;
-		} ul;
-		struct {
-			uint8_t tfi[8];
-		} dl;
-	} tbf;
 
 	/* fbsb state */
 	struct {
@@ -116,6 +106,8 @@ struct l1_model_ms {
 	struct l1ctl_sock_client *lsc;
 	/* pointer to the (shared) GSMTAP/VirtUM socket to talk to BTS(s) */
 	struct virt_um_inst *vui;
+	/* GPRS state (MAC layer) */
+	struct l1gprs_state *gprs;
 	/* actual per-MS state */
 	struct l1_state_ms state;
 };
diff --git a/src/host/virt_phy/src/Makefile.am b/src/host/virt_phy/src/Makefile.am
index 902284d0..f10639f5 100644
--- a/src/host/virt_phy/src/Makefile.am
+++ b/src/host/virt_phy/src/Makefile.am
@@ -5,6 +5,7 @@ bin_PROGRAMS = virtphy
 
 virtphy_SOURCES = \
 	virtphy.c \
+	l1gprs.c \
 	logging.c \
 	gsmtapl1_if.c \
 	l1ctl_sock.c \
@@ -13,6 +14,7 @@ virtphy_SOURCES = \
 	virt_prim_fbsb.c \
 	virt_prim_rach.c \
 	virt_prim_data.c \
+	virt_prim_pdch.c \
 	virt_prim_traffic.c \
 	virt_l1_sched_simple.c \
 	virt_l1_model.c \
diff --git a/src/host/virt_phy/src/gsmtapl1_if.c b/src/host/virt_phy/src/gsmtapl1_if.c
index f5c49af4..ef8d6840 100644
--- a/src/host/virt_phy/src/gsmtapl1_if.c
+++ b/src/host/virt_phy/src/gsmtapl1_if.c
@@ -94,23 +94,16 @@ void gsmtapl1_tx_to_virt_um_inst(struct l1_model_ms *ms, uint32_t fn, uint8_t tn
 	uint8_t timeslot;	/* tdma timeslot to send in (0-7) */
 	uint8_t gsmtap_chan;	/* the gsmtap channel */
 
-	switch (ms->state.state) {
-	case MS_STATE_DEDICATED:
-	case MS_STATE_TBF:
+	if (ms->state.state == MS_STATE_DEDICATED)
 		arfcn = ms->state.dedicated.band_arfcn;
-		break;
-	default:
+	else
 		arfcn = ms->state.serving_cell.arfcn;
-		break;
-	}
 
 	switch (l1h->msg_type) {
-	case L1CTL_DATA_TBF_REQ:
-		ul = NULL;
-		rsl_chantype = RSL_CHAN_OSMO_PDCH;
+	case L1CTL_GPRS_UL_BLOCK_REQ:
+		gsmtap_chan = GSMTAP_CHANNEL_PDCH;
 		timeslot = tn;
 		subslot = 0;
-		gsmtap_chan = chantype_rsl2gsmtap2(rsl_chantype, 0, false);
 		break;
 	case L1CTL_TRAFFIC_REQ:
 		ul = (struct l1ctl_info_ul *)l1h->data;
@@ -165,77 +158,6 @@ extern void prim_fbsb_sync(struct l1_model_ms *ms, struct msgb *msg);
  */
 extern uint16_t prim_pm_set_sig_strength(struct l1_model_ms *ms, uint16_t arfcn, int16_t sig_lev);
 
-/* determine if a received Downlink RLC/MAC block matches the current MS configuration */
-static bool gprs_dl_block_matches_ms(struct l1_model_ms *ms, struct msgb *msg, uint8_t timeslot)
-{
-	uint8_t payload_type;
-	uint8_t tfi;
-
-	if (msgb_length(msg) < 1)
-		return false;
-
-	/* FIXME: Ensure this will also work for EGPRS!  */
-	payload_type = msg->data[0] >> 6;
-	switch (payload_type) {
-	case 0: /* RLC Data Block */
-		/* forward all RLD Data Blocks destined for TFI of MS */
-		tfi = (msg->data[1] >> 1) & 0x1f;
-		if (ms->state.state == MS_STATE_TBF && ms->state.tbf.dl.tfi[timeslot] == tfi)
-			return true;
-		break;
-	case 1: /* RLC/MAC Control without optional octets */
-		/* forward all RLC/MAC control blocks without optional octets, i.e. not addressed
-		 * to a specific TFI */
-		return true;
-	case 2: /* RLC/MAC with optional control octets */
-		/* forward all RLD Control Blocks destined for TFI of MS */
-		tfi = (msg->data[2] >> 1) & 0x1f;
-		if (ms->state.state == MS_STATE_TBF && ms->state.tbf.dl.tfi[timeslot] == tfi)
-			return true;
-		break;
-	default:
-		break;
-	}
-	return false;
-}
-
-/* determine if given USF at given timeslot is relevant to given MS or not */
-static bool usf_matches_ms(struct l1_model_ms *ms, uint8_t usf, uint8_t timeslot)
-{
-	if (ms->state.state == MS_STATE_TBF && ms->state.tbf.ul.usf[timeslot] == usf)
-		return true;
-
-	return false;
-}
-
-/* extract USF from (E)GPRS RLC/MAC block */
-static uint8_t get_usf_from_block(struct msgb *msg)
-{
-	/* FIXME: Ensure this will also work for EGPRS!  */
-	return msg->data[0] & 0x7;
-}
-
-/* MS is authorized to transmit a block in uplink for given USF on timeslot+arfcn at FN */
-static void ms_ul_tbf_may_transmit(struct l1_model_ms *ms, uint16_t arfcn, uint8_t timeslot,
-				   uint32_t fn, uint8_t usf)
-{
-	struct msgb *msg;
-
-	/* If USF is not for us, bail out */
-	if (!usf_matches_ms(ms, usf, timeslot))
-		return;
-
-	/* attempt to de-queue pending msgb for this UL TBF and transmit it */
-	msg = msgb_dequeue(&ms->state.tbf.ul.tx_queue);
-	if (!msg) {
-		printf("FN=%u, TN=%u, USF=%u: empty tx_queue, not transmitting\n", fn, timeslot, usf);
-		/* FIXME: send some dummy control frame? */
-	} else {
-		printf("FN=%u, TN=%u, USF=%u: transmitting queued msg\n", fn, timeslot, usf);
-		gsmtapl1_tx_to_virt_um_inst(ms, fn, timeslot, msg);
-	}
-}
-
 static void l1ctl_from_virt_um(struct l1ctl_sock_client *lsc, struct msgb *msg, uint32_t fn,
 				uint16_t arfcn, uint8_t timeslot, uint8_t subslot,
 				uint8_t gsmtap_chantype, uint8_t chan_nr, uint8_t link_id,
@@ -243,7 +165,6 @@ static void l1ctl_from_virt_um(struct l1ctl_sock_client *lsc, struct msgb *msg,
 {
 	struct l1_model_ms *ms = lsc->priv;
 	uint8_t rxlev = dbm2rxlev(prim_pm_set_sig_strength(ms, arfcn & GSMTAP_ARFCN_MASK, MAX_SIG_LEV_DBM));
-	uint8_t usf;
 
 	gsm_fn2gsmtime(&ms->state.downlink_time, fn);
 
@@ -310,16 +231,13 @@ static void l1ctl_from_virt_um(struct l1ctl_sock_client *lsc, struct msgb *msg,
 	case GSMTAP_CHANNEL_RACH:
 		LOGPMS(DVIRPHY, LOGL_NOTICE, ms, "Ignoring unexpected RACH in downlink ?!?\n");
 		break;
+	case GSMTAP_CHANNEL_PTCCH:
 	case GSMTAP_CHANNEL_PACCH:
 	case GSMTAP_CHANNEL_PDCH:
-		if (gprs_dl_block_matches_ms(ms, msg, timeslot))
-			l1ctl_tx_data_ind(ms, msg, arfcn, link_id, chan_nr, fn, snr_db, rxlev, 0, 0);
-		usf = get_usf_from_block(msg);
-		ms_ul_tbf_may_transmit(ms, arfcn, timeslot, fn, usf);
+		l1ctl_tx_gprs_dl_block_ind(ms, msg, fn, timeslot, rxlev);
 		break;
 	case GSMTAP_CHANNEL_SDCCH:
 	case GSMTAP_CHANNEL_CCCH:
-	case GSMTAP_CHANNEL_PTCCH:
 		LOGPMS(DVIRPHY, LOGL_NOTICE, ms, "Ignoring unsupported channel type %s\n",
 			get_value_string(gsmtap_gsm_channel_names, gsmtap_chantype));
 		break;
diff --git a/src/host/virt_phy/src/l1ctl_sap.c b/src/host/virt_phy/src/l1ctl_sap.c
index ab917c6a..7e4540df 100644
--- a/src/host/virt_phy/src/l1ctl_sap.c
+++ b/src/host/virt_phy/src/l1ctl_sap.c
@@ -30,7 +30,6 @@
 #include <osmocom/gsm/protocol/gsm_08_58.h>
 #include <osmocom/gsm/protocol/gsm_04_08.h>
 #include <osmocom/gsm/rsl.h>
-#include <osmocom/gprs/gprs_rlc.h>
 
 #include <osmocom/bb/virtphy/virtual_um.h>
 #include <osmocom/bb/virtphy/l1ctl_sock.h>
@@ -40,9 +39,7 @@
 #include <osmocom/bb/virtphy/logging.h>
 #include <osmocom/bb/virtphy/virt_l1_sched.h>
 #include <osmocom/bb/l1ctl_proto.h>
-
-static void l1ctl_rx_tbf_cfg_req(struct l1_model_ms *ms, struct msgb *msg);
-static void l1ctl_rx_data_tbf_req(struct l1_model_ms *ms, struct msgb *msg);
+#include <osmocom/bb/l1gprs.h>
 
 static void l1_model_tch_mode_set(struct l1_model_ms *ms, uint8_t tch_mode)
 {
@@ -60,7 +57,6 @@ static void l1_model_tch_mode_set(struct l1_model_ms *ms, uint8_t tch_mode)
 void l1ctl_sap_init(struct l1_model_ms *model)
 {
 	INIT_LLIST_HEAD(&model->state.sched.mframe_items);
-	INIT_LLIST_HEAD(&model->state.tbf.ul.tx_queue);
 
 	prim_pm_init(model);
 }
@@ -163,8 +159,8 @@ static bool is_l1ctl_control(uint8_t msg_type)
 	switch (msg_type) {
 	case L1CTL_DATA_REQ:
 	case L1CTL_DATA_CONF:
-	case L1CTL_DATA_TBF_REQ:
-	case L1CTL_DATA_TBF_CONF:
+	case L1CTL_GPRS_UL_BLOCK_REQ:
+	case L1CTL_GPRS_DL_BLOCK_IND:
 	case L1CTL_TRAFFIC_REQ:
 	case L1CTL_TRAFFIC_CONF:
 	case L1CTL_TRAFFIC_IND:
@@ -247,11 +243,12 @@ void l1ctl_sap_handler(struct l1_model_ms *ms, struct msgb *msg)
 	case L1CTL_SIM_REQ:
 		l1ctl_rx_sim_req(ms, msg);
 		break;
-	case L1CTL_TBF_CFG_REQ:
-		l1ctl_rx_tbf_cfg_req(ms, msg);
+	case L1CTL_GPRS_UL_TBF_CFG_REQ:
+	case L1CTL_GPRS_DL_TBF_CFG_REQ:
+		l1ctl_rx_gprs_uldl_tbf_cfg_req(ms, msg);
 		break;
-	case L1CTL_DATA_TBF_REQ:
-		l1ctl_rx_data_tbf_req(ms, msg);
+	case L1CTL_GPRS_UL_BLOCK_REQ:
+		l1ctl_rx_gprs_ul_block_req(ms, msg);
 		goto exit_nofree;
 	}
 
@@ -297,6 +294,12 @@ void l1ctl_rx_dm_est_req(struct l1_model_ms *ms, struct msgb *msg)
 	ms->state.dedicated.subslot = subslot;
 	ms->state.state = MS_STATE_DEDICATED;
 
+	if (rsl_chantype == RSL_CHAN_OSMO_PDCH) {
+		OSMO_ASSERT(ms->gprs == NULL);
+		ms->gprs = l1gprs_state_alloc(ms, NULL, ms);
+		OSMO_ASSERT(ms->gprs != NULL);
+	}
+
 	/* TCH config */
 	if (rsl_chantype == RSL_CHAN_Bm_ACCHs || rsl_chantype == RSL_CHAN_Lm_ACCHs) {
 		ms->state.tch_mode = est_req->tch_mode;
@@ -381,6 +384,9 @@ void l1ctl_rx_dm_rel_req(struct l1_model_ms *ms, struct msgb *msg)
 	ms->state.tch_mode = GSM48_CMODE_SIGN;
 	ms->state.state = MS_STATE_IDLE_CAMPING;
 
+	l1gprs_state_free(ms->gprs);
+	ms->gprs = NULL;
+
 	/* TODO: disable ciphering */
 	/* TODO: disable audio recording / playing */
 }
@@ -429,6 +435,8 @@ void l1ctl_rx_reset_req(struct l1_model_ms *ms, struct msgb *msg)
 		DEBUGPMS(DL1C, ms, "Rx L1CTL_RESET_REQ (type=FULL)\n");
 		ms->state.state = MS_STATE_IDLE_SEARCHING;
 		virt_l1_sched_stop(ms);
+		l1gprs_state_free(ms->gprs);
+		ms->gprs = NULL;
 		l1ctl_tx_reset(ms, L1CTL_RESET_CONF, reset_req->type);
 		break;
 	case L1CTL_RES_T_SCHED:
@@ -547,145 +555,12 @@ void l1ctl_rx_sim_req(struct l1_model_ms *ms, struct msgb *msg)
 
 }
 
-static void l1ctl_tx_tbf_cfg_conf(struct l1_model_ms *ms, const struct l1ctl_tbf_cfg_req *in);
-
-static void l1ctl_rx_tbf_cfg_req(struct l1_model_ms *ms, struct msgb *msg)
-{
-	struct l1ctl_hdr *l1h = (struct l1ctl_hdr *) msg->data;
-	struct l1ctl_tbf_cfg_req *cfg_req = (struct l1ctl_tbf_cfg_req *) l1h->data;
-	unsigned int i;
-
-	LOGPMS(DL1C, LOGL_INFO, ms, "Rx L1CTL_TBF_CFG_REQ (tbf_id=%u, dir=%s, "
-		"usf=[%d,%d,%d,%d,%d,%d,%d,%d]\n", cfg_req->tbf_nr,
-		cfg_req->is_uplink ? "UL" : "DL", cfg_req->usf[0], cfg_req->usf[1],
-		cfg_req->usf[2], cfg_req->usf[3], cfg_req->usf[4], cfg_req->usf[5],
-		cfg_req->usf[6], cfg_req->usf[7]);
-
-	if (cfg_req->tbf_nr != 0) {
-		LOGPMS(DL1C, LOGL_ERROR, ms, "TBF_NR != 0 not supported yet!\n");
-		return;
-	}
-
-	if (ms->state.state == MS_STATE_DEDICATED)
-		LOGPMS(DL1C, LOGL_NOTICE, ms, "Hard termination of DEDICATED mode, fix L23!\n");
-
-	if (cfg_req->is_uplink) {
-		for (i = 0; i < 8; i++)
-			ms->state.tbf.ul.usf[i] = cfg_req->usf[i];
-	} else {
-		for (i = 0; i < 8; i++)
-			ms->state.tbf.dl.tfi[i] = cfg_req->usf[i];
-	}
-	ms->state.state = MS_STATE_TBF;
-
-	l1ctl_tx_tbf_cfg_conf(ms, cfg_req);
-}
-
-#if 0
-static const enum osmo_gprs_cs osmo_cs_by_l1ctl[] = {
-	[L1CTL_CS_NONE]	= OSMO_GPRS_CS_NONE,
-	[L1CTL_CS1]	= OSMO_GPRS_CS1,
-	[L1CTL_CS2]	= OSMO_GPRS_CS2,
-	[L1CTL_CS3]	= OSMO_GPRS_CS3,
-	[L1CTL_CS4]	= OSMO_GPRS_CS4,
-	[L1CTL_MCS1]	= OSMO_GPRS_MCS1,
-	[L1CTL_MCS2]	= OSMO_GPRS_MCS2,
-	[L1CTL_MCS3]	= OSMO_GPRS_MCS3,
-	[L1CTL_MCS4]	= OSMO_GPRS_MCS4,
-	[L1CTL_MCS5]	= OSMO_GPRS_MCS5,
-	[L1CTL_MCS6]	= OSMO_GPRS_MCS6,
-	[L1CTL_MCS7]	= OSMO_GPRS_MCS7,
-	[L1CTL_MCS8]	= OSMO_GPRS_MCS8,
-	[L1CTL_MCS9]	= OSMO_GPRS_MCS9,
-};
-
-static int get_osmo_cs_by_l1ctl(enum l1ctl_coding_scheme l1)
-{
-	if (l1 >= ARRAY_SIZE(osmo_cs_by_l1ctl))
-		return -1;
-	return osmo_cs_by_l1ctl[l1];
-}
-#endif
-
-static const enum l1ctl_coding_scheme l1ctl_cs_by_osmo[] = {
-	[OSMO_GPRS_CS_NONE]	= L1CTL_CS_NONE,
-	[OSMO_GPRS_CS1]		= L1CTL_CS1,
-	[OSMO_GPRS_CS2]		= L1CTL_CS2,
-	[OSMO_GPRS_CS3]		= L1CTL_CS3,
-	[OSMO_GPRS_CS4]		= L1CTL_CS4,
-	[OSMO_GPRS_MCS1]	= L1CTL_MCS1,
-	[OSMO_GPRS_MCS2]	= L1CTL_MCS2,
-	[OSMO_GPRS_MCS3]	= L1CTL_MCS3,
-	[OSMO_GPRS_MCS4]	= L1CTL_MCS4,
-	[OSMO_GPRS_MCS5]	= L1CTL_MCS5,
-	[OSMO_GPRS_MCS6]	= L1CTL_MCS6,
-	[OSMO_GPRS_MCS7]	= L1CTL_MCS7,
-	[OSMO_GPRS_MCS8]	= L1CTL_MCS8,
-	[OSMO_GPRS_MCS9]	= L1CTL_MCS9,
-};
-
-static int get_l1ctl_cs_by_osmo(enum osmo_gprs_cs in)
-{
-	if (in >= ARRAY_SIZE(l1ctl_cs_by_osmo))
-		return -1;
-	return l1ctl_cs_by_osmo[in];
-}
-
-static void l1ctl_rx_data_tbf_req(struct l1_model_ms *ms, struct msgb *msg)
-{
-	struct l1ctl_hdr *l1h = (struct l1ctl_hdr *) msg->data;
-	struct l1ctl_info_ul_tbf *udt = (struct l1ctl_info_ul_tbf *) l1h->data;
-	enum osmo_gprs_cs osmo_cs;
-	int block_size;
-
-	msg->l2h = udt->payload;
-
-	LOGPMS(DL1P, LOGL_ERROR, ms, "Rx L1CTL_DATA_TBF_REQ (tbf_id=%d, data=%s)\n",
-		udt->tbf_nr, osmo_hexdump(msg->l2h, msgb_l2len(msg)));
-	if (udt->tbf_nr != 0) {
-		LOGPMS(DL1C, LOGL_ERROR, ms, "TBF_NR != 0 not supported yet!\n");
-		return;
-	}
-
-	if (ms->state.state != MS_STATE_TBF) {
-		LOGPMS(DL1P, LOGL_ERROR, ms, "DATA_TBF_REQ in state != TBF\n");
-		return;
-	}
-
-	osmo_cs = get_l1ctl_cs_by_osmo(udt->coding_scheme);
-	if (osmo_cs < 0) {
-		LOGPMS(DL1P, LOGL_ERROR, ms, "DATA_RBF_REQ with invalid CS\n");
-		return;
-	}
-	block_size = osmo_gprs_ul_block_size_bytes(osmo_cs);
-
-	if (msgb_l2len(msg) < block_size) {
-		int pad_len = block_size - msgb_l2len(msg);
-		uint8_t *pad = msgb_put(msg, pad_len);
-		memset(pad, GSM_MACBLOCK_PADDING, pad_len);
-	}
-
-	msgb_enqueue(&ms->state.tbf.ul.tx_queue, msg);
-}
-
 /***************************************************************
  * L1CTL TX ROUTINES *******************************************
  * For more routines check the respective handler classes ******
  * like virt_prim_rach.c ***************************************
  ***************************************************************/
 
-static void l1ctl_tx_tbf_cfg_conf(struct l1_model_ms *ms, const struct l1ctl_tbf_cfg_req *in)
-{
-	struct msgb *msg = l1ctl_msgb_alloc(L1CTL_TBF_CFG_CONF);
-	struct l1ctl_tbf_cfg_req *out;
-
-	/* copy over the data from the request */
-	out = (struct l1ctl_tbf_cfg_req *) msgb_put(msg, sizeof(*out));
-	*out = *in;
-
-	l1ctl_sap_tx_to_l23_inst(ms, msg);
-}
-
 /**
  * @brief Transmit L1CTL_RESET_IND or L1CTL_RESET_CONF to layer 23.
  *
diff --git a/src/host/virt_phy/src/l1gprs.c b/src/host/virt_phy/src/l1gprs.c
new file mode 120000
index 00000000..0185f68b
--- /dev/null
+++ b/src/host/virt_phy/src/l1gprs.c
@@ -0,0 +1 @@
+../../../shared/l1gprs.c
\ No newline at end of file
diff --git a/src/host/virt_phy/src/logging.c b/src/host/virt_phy/src/logging.c
index 04667d1f..0a1b2a41 100644
--- a/src/host/virt_phy/src/logging.c
+++ b/src/host/virt_phy/src/logging.c
@@ -54,10 +54,10 @@ static const char* l1ctlPrimNames[] = {
 	"L1CTL_TRAFFIC_CONF",
 	"L1CTL_TRAFFIC_IND",
 	"L1CTL_BURST_IND",
-	"L1CTL_TBF_CFG_REQ",
-	"L1CTL_TBF_CFG_CONF",
-	"L1CTL_DATA_TBF_REQ",
-	"L1CTL_DATA_TBF_CONF"
+	"L1CTL_GPRS_UL_TBF_CFG_REQ",
+	"L1CTL_GPRS_DL_TBF_CFG_REQ",
+	"L1CTL_GPRS_UL_BLOCK_REQ",
+	"L1CTL_GPRS_DL_BLOCK_IND",
 };
 
 static const struct log_info_cat default_categories[] = {
@@ -82,6 +82,13 @@ static const struct log_info_cat default_categories[] = {
 		.enabled = 1,
 		.loglevel = LOGL_NOTICE,
 	},
+	[DGPRS] = {
+		.name = "DGPRS",
+		.description = "L1 GPRS (MAC leyer)",
+		.color = "\033[1;31m",
+		.enabled = 1,
+		.loglevel = LOGL_NOTICE,
+	},
 	[DMAIN] = {
 		.name = "DMAIN",
 		.description = "Main Program / Data Structures",
diff --git a/src/host/virt_phy/src/virt_prim_pdch.c b/src/host/virt_phy/src/virt_prim_pdch.c
new file mode 100644
index 00000000..7125a70b
--- /dev/null
+++ b/src/host/virt_phy/src/virt_prim_pdch.c
@@ -0,0 +1,106 @@
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ */
+
+#include <stdint.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/gsm/gsm_utils.h>
+#include <osmocom/gsm/protocol/gsm_08_58.h>
+
+#include <osmocom/bb/virtphy/l1ctl_sap.h>
+#include <osmocom/bb/virtphy/virt_l1_sched.h>
+#include <osmocom/bb/virtphy/gsmtapl1_if.h>
+#include <osmocom/bb/virtphy/logging.h>
+
+#include <osmocom/bb/l1ctl_proto.h>
+#include <osmocom/bb/l1gprs.h>
+
+void l1ctl_rx_gprs_uldl_tbf_cfg_req(struct l1_model_ms *ms, struct msgb *msg)
+{
+	const struct l1ctl_hdr *l1h = (struct l1ctl_hdr *)msg->data;
+
+	if (OSMO_UNLIKELY(ms->gprs == NULL)) {
+		LOGPMS(DL1C, LOGL_ERROR, ms, "l1gprs is not initialized\n");
+		return;
+	}
+
+	msg->l1h = msgb_pull(msg, sizeof(*l1h));
+
+	if (l1h->msg_type == L1CTL_GPRS_UL_TBF_CFG_REQ)
+		l1gprs_handle_ul_tbf_cfg_req(ms->gprs, msg);
+	else
+		l1gprs_handle_dl_tbf_cfg_req(ms->gprs, msg);
+}
+
+void l1ctl_rx_gprs_ul_block_req(struct l1_model_ms *ms, struct msgb *msg)
+{
+	const struct l1ctl_hdr *l1h = (struct l1ctl_hdr *)msg->data;
+	struct l1gprs_prim_ul_block_req req;
+	uint32_t fn_sched;
+
+	if (OSMO_UNLIKELY(ms->gprs == NULL)) {
+		LOGPMS(DL1P, LOGL_ERROR, ms, "l1gprs is not initialized\n");
+		return;
+	}
+
+	msg->l1h = (void *)l1h->data;
+	if (l1gprs_handle_ul_block_req(ms->gprs, &req, msg) != 0)
+		return;
+	msg->l2h = (void *)&req.data[0];
+
+	fn_sched = sched_fn_ul(ms->state.current_time,
+			       RSL_CHAN_OSMO_PDCH | req.hdr.tn, 0x00);
+	if (OSMO_UNLIKELY(fn_sched != req.hdr.fn)) {
+		LOGPMS(DL1P, LOGL_ERROR, ms,
+		       "GPRS UL BLOCK.req: fn_sched(%u) != fn_req(%u)\n",
+		       fn_sched, req.hdr.fn);
+		/* FIXME: return; */
+	}
+
+	virt_l1_sched_schedule(ms, msg, fn_sched, req.hdr.tn,
+			       &gsmtapl1_tx_to_virt_um_inst);
+}
+
+void l1ctl_tx_gprs_dl_block_ind(struct l1_model_ms *ms, const struct msgb *msg,
+				uint32_t fn, uint8_t tn, uint8_t rxlev)
+{
+	struct l1gprs_prim_dl_block_ind ind;
+	struct msgb *nmsg;
+
+	if (ms->gprs == NULL)
+		return;
+
+	ind = (struct l1gprs_prim_dl_block_ind) {
+		.hdr = {
+			.fn = fn,
+			.tn = tn,
+		},
+		.meas = {
+			.ber10k = 0, /* perfect Um, no errors */
+			.ci_cb = 180, /* 18 dB */
+			.rx_lev = rxlev,
+		},
+		.data = msgb_data(msg),
+		.data_len = msgb_length(msg),
+	};
+
+	nmsg = l1gprs_handle_dl_block_ind(ms->gprs, &ind);
+	if (nmsg != NULL)
+		l1ctl_sap_tx_to_l23_inst(ms, nmsg);
+}
diff --git a/src/host/virt_phy/src/virtphy.c b/src/host/virt_phy/src/virtphy.c
index ad09a53c..005ae2dd 100644
--- a/src/host/virt_phy/src/virtphy.c
+++ b/src/host/virt_phy/src/virtphy.c
@@ -40,8 +40,9 @@
 #include <osmocom/bb/virtphy/gsmtapl1_if.h>
 #include <osmocom/bb/virtphy/logging.h>
 #include <osmocom/bb/virtphy/virt_l1_sched.h>
+#include <osmocom/bb/l1gprs.h>
 
-#define DEFAULT_LOG_MASK "DL1C,2:DL1P,2:DVIRPHY,2:DMAIN,1"
+#define DEFAULT_LOG_MASK "DL1C,2:DL1P,2:DVIRPHY,2:DGPRS,1:DMAIN,1"
 
 /* this exists once in the program, and contains the state that we
  * only keep once:  L1CTL server socket, GSMTAP/VirtUM socket */
@@ -242,6 +243,7 @@ int main(int argc, char *argv[])
 	handle_options(argc, argv);
 
 	ms_log_init(log_mask);
+	l1gprs_logging_init(DGPRS);
 
 	LOGP(DVIRPHY, LOGL_INFO, "Virtual physical layer starting up...\n");
 
diff --git a/src/shared/l1gprs.c b/src/shared/l1gprs.c
new file mode 100644
index 00000000..3babd2b5
--- /dev/null
+++ b/src/shared/l1gprs.c
@@ -0,0 +1,457 @@
+/*
+ * l1gprs - GPRS layer 1 implementation
+ *
+ * (C) 2022-2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ */
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <arpa/inet.h>
+
+#include <osmocom/core/logging.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/msgb.h>
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/protocol/gsm_44_060.h>
+
+#include <osmocom/bb/l1ctl_proto.h>
+#include <osmocom/bb/l1gprs.h>
+
+#define LOGP_GPRS(gprs, level, fmt, args...) \
+	LOGP(l1gprs_log_cat, level, "%s" fmt, \
+	     (gprs)->log_prefix, ## args)
+
+#define LOGP_PDCH(pdch, level, fmt, args...) \
+	LOGP_GPRS((pdch)->gprs, level, "(PDCH-%u) " fmt, \
+		  (pdch)->tn, ## args)
+
+#define LOG_TBF_FMT "%cL-TBF#%03d"
+#define LOG_TBF_ARGS(tbf) \
+	(tbf)->uplink ? 'U' : 'D', tbf->tbf_ref
+
+static int l1gprs_log_cat = DLGLOBAL;
+
+enum gprs_rlcmac_block_type {
+	GPRS_RLCMAC_DATA_BLOCK		= 0x00,
+	GPRS_RLCMAC_CONTROL_BLOCK	= 0x01,
+	GPRS_RLCMAC_CONTROL_BLOCK_OPT	= 0x02,
+	GPRS_RLCMAC_RESERVED		= 0x03,
+};
+
+static struct l1gprs_tbf *l1gprs_tbf_alloc(struct l1gprs_state *gprs,
+					   bool uplink, uint8_t tbf_ref,
+					   uint8_t slotmask)
+{
+	struct l1gprs_tbf *tbf;
+
+	tbf = talloc(gprs, struct l1gprs_tbf);
+	OSMO_ASSERT(tbf != NULL);
+
+	tbf->uplink = uplink;
+	tbf->tbf_ref = tbf_ref;
+	tbf->slotmask = slotmask;
+
+	return tbf;
+}
+
+static void l1gprs_tbf_free(struct l1gprs_tbf *tbf)
+{
+	if (tbf == NULL)
+		return;
+	llist_del(&tbf->list);
+	talloc_free(tbf);
+}
+
+static struct l1gprs_tbf *l1gprs_find_tbf(struct l1gprs_state *gprs,
+					  bool uplink, uint8_t tbf_ref)
+{
+	struct l1gprs_tbf *tbf;
+
+	llist_for_each_entry(tbf, &gprs->tbf_list, list) {
+		if (tbf->uplink != uplink)
+			continue;
+		if (tbf->tbf_ref != tbf_ref)
+			continue;
+		return tbf;
+	}
+
+	return NULL;
+}
+
+static void l1gprs_register_tbf(struct l1gprs_state *gprs,
+				struct l1gprs_tbf *tbf)
+{
+	OSMO_ASSERT(tbf->slotmask != 0x00);
+
+	/* Update the PDCH states */
+	for (unsigned int tn = 0; tn < ARRAY_SIZE(gprs->pdch); tn++) {
+		struct l1gprs_pdch *pdch = &gprs->pdch[tn];
+
+		if (~tbf->slotmask & (1 << pdch->tn))
+			continue;
+
+		if (tbf->uplink) {
+			pdch->ul_tbf_count++;
+		} else {
+			pdch->dl_tbf_count++;
+			pdch->dl_tfi_mask |= (1 << tbf->dl_tfi);
+		}
+
+		LOGP_PDCH(pdch, LOGL_DEBUG,
+			  "Linked " LOG_TBF_FMT "\n",
+			  LOG_TBF_ARGS(tbf));
+	}
+
+	llist_add_tail(&tbf->list, &gprs->tbf_list);
+
+	LOGP_GPRS(gprs, LOGL_INFO,
+		  LOG_TBF_FMT " is registered\n",
+		  LOG_TBF_ARGS(tbf));
+}
+
+static void l1gprs_unregister_tbf(struct l1gprs_state *gprs,
+				  bool uplink, uint8_t tbf_ref)
+{
+	struct l1gprs_tbf *tbf;
+
+	tbf = l1gprs_find_tbf(gprs, uplink, tbf_ref);
+	if (tbf == NULL) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "%s(): " LOG_TBF_FMT " not found\n",
+			  __func__, LOG_TBF_ARGS(tbf));
+		return;
+	}
+
+	/* Update the PDCH states */
+	for (unsigned int tn = 0; tn < ARRAY_SIZE(gprs->pdch); tn++) {
+		struct l1gprs_pdch *pdch = &gprs->pdch[tn];
+
+		if (~tbf->slotmask & (1 << pdch->tn))
+			continue;
+
+		if (tbf->uplink) {
+			OSMO_ASSERT(pdch->ul_tbf_count > 0);
+			pdch->ul_tbf_count--;
+		} else {
+			OSMO_ASSERT(pdch->dl_tbf_count > 0);
+			pdch->dl_tbf_count--;
+			pdch->dl_tfi_mask &= ~(1 << tbf->dl_tfi);
+		}
+
+		LOGP_PDCH(pdch, LOGL_DEBUG,
+			  "Unlinked " LOG_TBF_FMT "\n",
+			  LOG_TBF_ARGS(tbf));
+	}
+
+	LOGP_GPRS(gprs, LOGL_INFO,
+		  LOG_TBF_FMT " is unregistered and free()d\n",
+		  LOG_TBF_ARGS(tbf));
+
+	l1gprs_tbf_free(tbf);
+}
+
+#define L1GPRS_L1CTL_MSGB_SIZE		256
+#define L1GPRS_L1CTL_MSGB_HEADROOM	32
+
+static struct msgb *l1gprs_l1ctl_msgb_alloc(uint8_t msg_type)
+{
+	struct l1ctl_hdr *l1h;
+	struct msgb *msg;
+
+	msg = msgb_alloc_headroom(L1GPRS_L1CTL_MSGB_SIZE,
+				  L1GPRS_L1CTL_MSGB_HEADROOM,
+				  "l1gprs_l1ctl_msg");
+	if (msg == NULL)
+		return NULL;
+
+	msg->l1h = msgb_put(msg, sizeof(*l1h));
+	l1h = (struct l1ctl_hdr *)msg->l1h;
+	l1h->msg_type = msg_type;
+
+	return msg;
+}
+
+static bool l1gprs_pdch_filter_dl_block(const struct l1gprs_pdch *pdch,
+					const uint8_t *data)
+{
+	enum gprs_rlcmac_block_type block_type = data[0] >> 6;
+	uint8_t dl_tfi;
+
+	switch (block_type) {
+	case GPRS_RLCMAC_DATA_BLOCK:
+		/* see 3GPP TS 44.060, section 10.2.1 */
+		dl_tfi = (data[1] >> 1) & 0x1f;
+		break;
+	case GPRS_RLCMAC_CONTROL_BLOCK_OPT:
+		/* see 3GPP TS 44.060, section 10.3.1 */
+		dl_tfi = (data[2] >> 1) & 0x1f;
+		break;
+	case GPRS_RLCMAC_CONTROL_BLOCK:
+		/* no optional octets */
+		return true;
+	default:
+		LOGP_PDCH(pdch, LOGL_NOTICE,
+			  "Rx Downlink block with unknown payload (0x%0x)\n",
+			  block_type);
+		return false;
+	}
+
+	if (pdch->dl_tfi_mask & (1 << dl_tfi))
+		return true;
+	return false;
+}
+
+///////////////////////////////////////////////////////////////////////////////////
+
+void l1gprs_logging_init(int logc)
+{
+	l1gprs_log_cat = logc;
+}
+
+struct l1gprs_state *l1gprs_state_alloc(void *ctx, const char *log_prefix, void *priv)
+{
+	struct l1gprs_state *gprs;
+
+	gprs = talloc_zero(ctx, struct l1gprs_state);
+	if (gprs == NULL)
+		return NULL;
+
+	for (unsigned int tn = 0; tn < ARRAY_SIZE(gprs->pdch); tn++) {
+		struct l1gprs_pdch *pdch = &gprs->pdch[tn];
+
+		pdch->tn = tn;
+		pdch->gprs = gprs;
+	}
+
+	INIT_LLIST_HEAD(&gprs->tbf_list);
+
+	if (log_prefix == NULL)
+		gprs->log_prefix = talloc_asprintf(gprs, "l1gprs[0x%p]: ", gprs);
+	else
+		gprs->log_prefix = talloc_strdup(gprs, log_prefix);
+	gprs->priv = priv;
+
+	return gprs;
+}
+
+void l1gprs_state_free(struct l1gprs_state *gprs)
+{
+	if (gprs == NULL)
+		return;
+
+	while (!llist_empty(&gprs->tbf_list)) {
+		struct l1gprs_tbf *tbf;
+
+		tbf = llist_first_entry(&gprs->tbf_list, struct l1gprs_tbf, list);
+		LOGP_GPRS(gprs, LOGL_DEBUG,
+			  "%s(): " LOG_TBF_FMT " is free()d\n",
+			  __func__, LOG_TBF_ARGS(tbf));
+		l1gprs_tbf_free(tbf);
+	}
+
+	talloc_free(gprs->log_prefix);
+	talloc_free(gprs);
+}
+
+int l1gprs_handle_ul_tbf_cfg_req(struct l1gprs_state *gprs, const struct msgb *msg)
+{
+	const struct l1ctl_gprs_ul_tbf_cfg_req *req = (void *)msg->l1h;
+	struct l1gprs_tbf *tbf = NULL;
+
+	OSMO_ASSERT(req != NULL);
+
+	if (msgb_l1len(msg) < sizeof(*req)) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Rx malformed Uplink TBF config (len=%u < %zu)\n",
+			  msgb_l1len(msg), sizeof(*req));
+		return -EINVAL;
+	}
+
+	LOGP_GPRS(gprs, LOGL_INFO,
+		  "Rx Uplink TBF config: tbf_ref=%u, slotmask=0x%02x\n",
+		  req->tbf_ref, req->slotmask);
+
+	if (req->slotmask != 0x00) {
+		tbf = l1gprs_tbf_alloc(gprs, true, req->tbf_ref, req->slotmask);
+		l1gprs_register_tbf(gprs, tbf);
+	} else {
+		l1gprs_unregister_tbf(gprs, true, req->tbf_ref);
+	}
+
+	return 0;
+}
+
+int l1gprs_handle_dl_tbf_cfg_req(struct l1gprs_state *gprs, const struct msgb *msg)
+{
+	const struct l1ctl_gprs_dl_tbf_cfg_req *req = (void *)msg->l1h;
+	struct l1gprs_tbf *tbf = NULL;
+
+	OSMO_ASSERT(req != NULL);
+
+	if (msgb_l1len(msg) < sizeof(*req)) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Rx malformed Downlink TBF config (len=%u < %zu)\n",
+			  msgb_l1len(msg), sizeof(*req));
+		return -EINVAL;
+	}
+
+	LOGP_GPRS(gprs, LOGL_INFO,
+		  "Rx Downlink TBF config: tbf_ref=%u, slotmask=0x%02x, dl_tfi=%u\n",
+		  req->tbf_ref, req->slotmask, req->dl_tfi);
+
+	if (req->dl_tfi > 31) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Invalid DL TFI %u (shall be in range 0..31)\n",
+			  req->dl_tfi);
+		return -EINVAL;
+	}
+
+	if (req->slotmask != 0x00) {
+		tbf = l1gprs_tbf_alloc(gprs, false, req->tbf_ref, req->slotmask);
+		tbf->dl_tfi = req->dl_tfi;
+		l1gprs_register_tbf(gprs, tbf);
+	} else {
+		l1gprs_unregister_tbf(gprs, false, req->tbf_ref);
+	}
+
+	return 0;
+}
+
+int l1gprs_handle_ul_block_req(struct l1gprs_state *gprs,
+			       struct l1gprs_prim_ul_block_req *req,
+			       const struct msgb *msg)
+{
+	const struct l1ctl_gprs_ul_block_req *l1br = (void *)msg->l1h;
+	const struct l1gprs_pdch *pdch = NULL;
+	size_t data_len;
+
+	OSMO_ASSERT(l1br != NULL);
+
+	if (OSMO_UNLIKELY(msgb_l1len(msg) < sizeof(*l1br))) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Rx malformed UL BLOCK.req (len=%u < %zu)\n",
+			  msgb_l1len(msg), sizeof(*l1br));
+		return -EINVAL;
+	}
+	if (OSMO_UNLIKELY(l1br->hdr.tn >= ARRAY_SIZE(gprs->pdch))) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Rx malformed UL BLOCK.req (tn=%u)\n",
+			  l1br->hdr.tn);
+		return -EINVAL;
+	}
+
+	pdch = &gprs->pdch[l1br->hdr.tn];
+	data_len = msgb_l1len(msg) - sizeof(*l1br);
+
+	LOGP_PDCH(pdch, LOGL_DEBUG,
+		  "Rx UL BLOCK.req (fn=%u, len=%zu): %s\n",
+		  ntohl(l1br->hdr.fn), data_len, osmo_hexdump(l1br->data, data_len));
+
+	if ((pdch->ul_tbf_count == 0) && (pdch->dl_tbf_count == 0)) {
+		LOGP_PDCH(pdch, LOGL_ERROR,
+			  "Rx UL BLOCK.req, but this PDCH has no configured TBFs\n");
+		return -EINVAL;
+	}
+
+	*req = (struct l1gprs_prim_ul_block_req) {
+		.hdr = {
+			.fn = ntohl(l1br->hdr.fn),
+			.tn = l1br->hdr.tn,
+		},
+		.data = &l1br->data[0],
+		.data_len = data_len,
+	};
+
+	return 0;
+}
+
+struct msgb *l1gprs_handle_dl_block_ind(struct l1gprs_state *gprs,
+					const struct l1gprs_prim_dl_block_ind *ind)
+{
+	const struct l1gprs_pdch *pdch = NULL;
+	struct l1ctl_gprs_dl_block_ind *l1bi;
+	enum osmo_gprs_cs cs;
+	struct msgb *msg;
+
+	if (OSMO_UNLIKELY(ind->hdr.tn >= ARRAY_SIZE(gprs->pdch))) {
+		LOGP_GPRS(gprs, LOGL_ERROR,
+			  "Rx malformed DL BLOCK.ind (tn=%u)\n",
+			  ind->hdr.tn);
+		return NULL;
+	}
+
+	pdch = &gprs->pdch[ind->hdr.tn];
+
+	LOGP_PDCH(pdch, LOGL_DEBUG,
+		  "Rx DL BLOCK.ind (fn=%u, len=%zu): %s\n",
+		  ind->hdr.fn, ind->data_len, osmo_hexdump(ind->data, ind->data_len));
+
+	if ((pdch->ul_tbf_count == 0) && (pdch->dl_tbf_count == 0)) {
+		LOGP_PDCH(pdch, LOGL_ERROR,
+			  "Rx DL BLOCK.ind, but this PDCH has no configured TBFs\n");
+		return NULL;
+	}
+
+	msg = l1gprs_l1ctl_msgb_alloc(L1CTL_GPRS_DL_BLOCK_IND);
+	if (OSMO_UNLIKELY(msg == NULL)) {
+		LOGP_GPRS(gprs, LOGL_ERROR, "l1gprs_l1ctl_msgb_alloc() failed\n");
+		return NULL;
+	}
+
+	l1bi = (void *)msgb_put(msg, sizeof(*l1bi));
+	*l1bi = (struct l1ctl_gprs_dl_block_ind) {
+		.hdr = {
+			.fn = htonl(ind->hdr.fn),
+			.tn = ind->hdr.tn,
+		},
+		.meas = {
+			.ber10k = htons(ind->meas.ber10k),
+			.ci_cb = htons(ind->meas.ci_cb),
+			.rx_lev = ind->meas.rx_lev,
+		},
+		.usf = 0xff,
+	};
+
+	if (ind->data_len == 0)
+		return msg;
+
+	cs = osmo_gprs_dl_cs_by_block_bytes(ind->data_len);
+	switch (cs) {
+	case OSMO_GPRS_CS1:
+	case OSMO_GPRS_CS2:
+	case OSMO_GPRS_CS3:
+	case OSMO_GPRS_CS4:
+		l1bi->usf = ind->data[0] & 0x07;
+		/* Determine whether to include the payload or not */
+		if (l1gprs_pdch_filter_dl_block(pdch, ind->data))
+			memcpy(msgb_put(msg, ind->data_len), ind->data, ind->data_len);
+		break;
+	case OSMO_GPRS_CS_NONE:
+		LOGP_PDCH(pdch, LOGL_ERROR,
+			  "Failed to determine Coding Scheme (len=%zu)\n", ind->data_len);
+		break;
+	default:
+		LOGP_PDCH(pdch, LOGL_NOTICE, "Coding Scheme %d is not supported\n", cs);
+		break;
+	}
+
+	return msg;
+}