WIP V110laforge/libosmoisdn

Change-Id: I5716bd6fd0201ee7a7a29e72f775972cd374082f

1 files changed, 330 insertions, 0 deletions

diff --git a/src/isdn/v110.c b/src/isdn/v110.c
index 46962bfa..47f4aabd 100644
--- a/src/isdn/v110.c
+++ b/src/isdn/v110.c
@@ -30,6 +30,8 @@
 #include <errno.h>
 
 #include <osmocom/core/bits.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/fsm.h>
 
 #include <osmocom/isdn/v110.h>
 
@@ -581,3 +583,331 @@ int osmo_v110_sync_ra1_ir_to_user(enum osmo_v100_sync_ra1_rate rate, ubit_t *d_o
 
 	return osmo_v110_sync_ra1_def[rate].adapt_ir_to_user(d_out, out_len, fr);
 }
+
+/*********************************************************************************
+ * V.110 TERMINAL ADAPTER FSMs
+ *********************************************************************************/
+
+enum v110_ta_state {
+	V110_TA_S_IDLE_READY,		/* Idle (or ready) state */
+	V110_TA_S_CON_TA_LINE,		/* Connect TA to line state */
+	V110_TA_S_DATA_TRANSFER,	/* Data transfer state */
+	V110_TA_S_RESYNCING,		/* Re-synchronizing state */
+};
+
+enum v110_ta_event {
+	V110_TA_E_RX_FRAME_IND,		/* Received V.110 frame indication */
+	V110_TA_E_TX_FRAME_RTS,		/* V.110 frame Ready-to-send indication */
+};
+
+static const struct value_string v110_ta_event_names[] = {
+	{ V110_TA_E_RX_FRAME_IND,	"RX_FRAME_IND" },
+	{ V110_TA_E_TX_FRAME_RTS,	"TX_FRAME_RTS" },
+	{ 0, NULL }
+};
+
+enum v110_ta_tx_d_bit_mode {
+	V110_TA_TX_FRAME_ALL_ONE,
+	V110_TA_TX_FRAME_ALL_ZERO,
+	V110_TA_TX_FRAME_FROM_DTE,
+};
+
+struct v110_ta_state {
+	/* V.24 status flags shared between DTE (user) and DCE (TA, us) */
+	v24_flagmask	v24_flags;
+	struct {
+		/* is end-to-end flow-control enabled or not? */
+		bool end_to_end_flowctrl;
+		/* synchronous user rate */
+		enum osmo_v100_sync_ra1_rate rate;
+	} cfg;
+	struct {
+		/* what kind of D-bits to transmit in V.110 frames */
+		enum v110_ta_tx_d_bit_mode d_bit_mode;
+		/* what to put in S-bits of transmitted V.110 frames (true = ON) */
+		bool s_bits;
+		/* what to put in X-bits of transmitted V.110 frames (true = OFF) */
+		bool x_bits;
+		/* what to put in E-bits of transmitted V.110 frames */
+		ubit_t e_bits[MAX_E_BITS];
+	} tx;
+	struct { 
+		enum v11o_ta_tx_d_bit_mode bit_mode;
+	} rx;
+};
+
+/* build one V.110 frame to transmit */
+static void v110_ta_build_frame(struct osmo_v110_decoded_frame *out, struct osmo_fsm_inst *fi)
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+
+	/* D-bits */
+	switch (ts->tx.d_bit_mode) {
+	case V110_TA_TX_FRAME_ALL_ONE:
+		memset(out->d_bits, 1, sizeof(out->d_bits));
+		break;
+	case V110_TA_TX_FRAME_ALL_ZERO:
+		memset(out->d_bits, 0, sizeof(out->d_bits));
+		break;
+	case V110_TA_TX_FRAME_FROM_DTE:
+		//FIXME: retrieve user bits */
+		rc = osmo_v110_sync_ra1_user_to_ir(ts->cfg.rate, out, user_bits, num_user_bits);
+		OSMO_ASSERT(rc == 0);
+		break;
+	};
+
+	/* E-bits */
+	memcpy(out->e_bits, ts->tx.e_bits, sizeof(out->e_bits));
+
+	/* S-bits */
+	if (ts->tx.s_bits == true)
+		memset(out->s_bits, 0, sizeof(out->s_bits));
+	else
+		memset(out->s_bits, 1, sizeof(out->s_bits));
+
+	/* X-bits */
+	if (ts->tx.x_bits == true)
+		memset(out->x_bits, 0, sizeof(out->x_bits));
+	else
+		memset(out->x_bits, 1, sizeof(out->x_bits));
+}
+
+static void v24_flags_updated(struct osmo_fsm_inst *fi)
+{
+	/* FIXME: somehow notify the USART about it */
+}
+
+/* ITU-T V.110 Section 7.1.1 */
+static void v110fsm_ta_idle_ready_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state);
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+
+	/* E4 .. E7 bits (lower 3 bits are generated by v110 frame encoder) */
+	memset(ts->tx.e_bits+3, 1, 4);
+	ts->user_data_cunk_bitlen = osmo_v110_sync_ra1_get_user_data_chunk_bitlen(ts->cfg.rate);
+
+	/* 7.1.1.2 During the idle (or ready) state the TA will transmit continuous binary 1s into the B-channel */
+	/* 7.1.1.3 During the idle (or ready) state the TA (DCE) will transmit the following toward the DTE: * */
+	/* - 104: continuous binary 1*/
+	ts->rx.bit_mode = V110_TA_TX_FRAME_ALL_ONE;
+	/* - 107, 106, 109 = OFF */
+	V24_FLAGMASK_SET_OFF(ts->v24_flags, OSMO_V24_C_106);
+	V24_FLAGMASK_SET_OFF(ts->v24_flags, OSMO_V24_C_107);
+	V24_FLAGMASK_SET_OFF(ts->v24_flags, OSMO_V24_C_109);
+	v24_flags_updated(fi);
+}
+
+/* ITU-T V.110 Section 7.1.1 */
+static void v110fsm_ta_idle_ready(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+	const struct osmo_v110_decoded_frame *fr = NULL;
+	int rc;
+
+	switch (event) {
+	case V110_TA_E_RX_FRAME_IND:
+		fr = data;
+		rc = osmo_v110_sync_ra1_ir_to_user(ts->cfg.rate, d_out, out_len, fr);
+		break;
+	case V110_TA_E_TX_FRAME_RTS:
+		/* transmit continuous binary 1 to B channels */
+		break;
+	case V110_TA_E_SWITCH_TO_DATA_MODE:
+		/* When the TA is to be switched to the data mode, circuit 108 must be ON */
+		if (V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V24_C_108_2)) {
+			/* 7.12.2: Start timer T1 when switching to CON_TA_LINE */
+			osmo_fsm_inst_state_chg(fi, V110_TA_S_CON_TA_LINE, 10, 1);
+		}
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+/* ITU-t V.110 Section 7.1.2 */
+static void v110fsm_ta_connect_to_line_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state);
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+
+	/* frame sync pattern as per 5.1.3.1 / 5.2.1 */
+	FIXME
+	/* data bits: binary 1 */
+	ts->tx.d_bit_mode = V110_TA_TX_FRAME_ALL_ONE;
+	/* S = OFF, X = OFF (ON = binary 0; OFF = binary 1) */
+	ts->tx.s_bits = false;
+	ts->tx.x_bits = false;
+	/* onenter: T1 has been started */
+	OSMO_ASSERT(fi->T = 1);
+}
+
+static bool all_bits_are(const ubit_t *in, ubit_t cmp, size_t in_len)
+{
+	for (unsigned int i = 0; i < in_len; i++) {
+		if (in[i] != cmp)
+			return false;
+	}
+	return true;
+}
+#define ARRAY_ALL_BITS_ONE(arr)		all_bits_are((arr), 1, sizeof(arr))
+#define ARRAY_ALL_BITS_ZERO(arr)	all_bits_are((arr), 0, sizeof(arr))
+
+/* ITU-t V.110 Section 7.1.2 */
+static void v110fsm_ta_connect_ta_to_line(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+	struct osmo_v110_decoded_frame *fr = NULL;
+
+	switch (event) {
+	case V110_TA_E_RX_FRAME_IND:
+		fr = data;
+		if (ARRAY_ALL_BITS_ZERO(fr->s_bits) && ARRAY_ALL_BITS_ZERO(fr->x_bits)) {
+			/* 7.1.2.4 When the receiver recognizes that the status of bits S and X are in the ON
+			 * condition, it will perform the following functions: */
+			/* a) Turn ON circuit 107 toward the DTE and stop timer T1. */
+			V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_107);
+			/* b) Then, circuit 103 may be connected to the data bits in the frame; however, the
+			 * DTE must maintain a binary 1 condition on circuit 103 until circuit 106 is turned
+			 * ON in the next portion of the sequence. */
+			/* c) Turn ON circuit 109 and connect the data bits to circuit 104. */
+			V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_109);
+			/* d) After an interval of N bits (see 6.3), it will turn ON circuit 106. */
+			V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_106);
+			v24_flags_updated(fi);
+			/* Circuit 106 transitioning from OFF to ON will cause the transmitted data to
+			 * transition from binary 1 to the data mode. */
+			osmo_fsm_inst_state_chg(fi, V110_TA_S_DATA_XFER, 0, 0);
+
+			rc = osmo_v110_sync_ra1_ir_to_user(ts->cfg.rate, d_out, out_len, fr);
+		}
+		break;
+	case V110_TA_E_TX_FRAME_RTS:
+		fr = data;
+		v110_ta_build_frame(fr, fi);
+		break;
+	case V110_TA_E_RX_SYNC_IND:
+		/* 7.1.2.3 When the receiver recognizes the frame synchronization pattern, it causes the S-
+		 * and X-bits in the transmitted frames to be turned ON (provided that circuit 108 is ON). */
+		if (V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V24_C_108_2)) {
+			ts->tx.s_bits = true;
+			ts->tx.x_bits = true;
+		}
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+/* ITU-t V.110 Section 7.1.3 */
+static void v110fsm_ta_data_transfer_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+
+	ts->tx.d_bit_mode = V110_TA_TX_FRAME_FROM_DTE;
+
+	/* 7.1.3.1 a): 105, 107, 108/1, 108/2 and 109 are in the ON condition */
+	V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_105);
+	V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_107);
+	V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_108_1);
+	V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_108_2);
+	V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_109);
+	/* 7.1.3.1 c): 133 (when implemented) and 106 are in the ON condition unless local out-of-band
+	   flow control is being used, either or both circuits may be in the ON or the OFF condition. */
+	if (!ts->cfg.end_to_end_flowctrl) {
+		V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_133);
+		V24_FLAGMASK_SET_ON(ts->v24_flags, OSMO_V24_C_106);
+	}
+	v24_flags_updated(fi);
+	/* 7.1.3.2 While in the data transfer state, the following status bit conditions exist: */
+	/* a) status bits S in both directions are in the ON condition; */
+	ts->tx.s_bits = true;
+	/* b) status bits X in both directions are in the ON condition unless end-to-end flow control is
+	      being used, in which case status bit X in either or both directions may be in the ON or the OFF
+	      condition. */
+	if (!ts->cfg.end_to_end_flowctrl) {
+		ts->tx.x_bits = true;
+	}
+}
+
+/* ITU-t V.110 Section 7.1.3 */
+static void v110fsm_ta_data_transfer(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct v110_ta_state *ts = (struct v110_ta_state *) fi->priv;
+	struct osmo_v110_decoded_frame *fr = NULL;
+
+	switch (event) {
+	case V110_TA_E_RX_V24_STATUS_CHG:
+		/* 7.1.4.1 At the completion of the data transfer phase, the local DTE will indicate a
+		 * disconnect request by turning OFF circuit 108 */
+		if (V24_FLAGMASK_IS_OFF(ts->v24_flags, OSMO_V24_C_108_2)) {
+			/* a) the status bits S in the frame toward ISDN will turn OFF, status bits X are kept ON */
+			ts->tx.s_bits = false;
+			/* b) circuit 106 will be turned OFF */
+			V24_FLAGMASK_SET_OFF(ts->v24_flags, OSMO_V24_C_106);
+			v24_flags_updated(fi);
+			/* c) the data bits in the frame will be set to binary 0. */
+			ts->tx.d_bit_mode = V110_TA_TX_FRAME_ALL_ZERO;
+			/* to guard against the failure of the remote TA to respond to the disconnect request,
+			 * the local TA may start a timer T2 (suggested value 5 s) which is stopped by the
+			 * reception or transmission of any D-channel clearing message (DISCONNECT, RELEASE,
+			 * RELEASE COMPLETE) */
+			osmo_fsm_inst_state_chg(fi, V110_TA_S_WAIT_DISC_CONF, 5, 2);
+		}
+		break;
+	case V110_TA_E_TX_FRAME_RTS:
+		fr = data;
+		v110_ta_build_frame(fr, fi);
+		break;
+	case V110_TA_E_RX_FRAME_IND:
+		fr = data;
+		rc = osmo_v110_sync_ra1_ir_to_user(ts->cfg.rate, d_out, out_len, fr);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static int v110_ta_timer_cb(struct osmo_fsm_inst *fi)
+{
+	switch (fi->T) {
+	case 1:	/* T1: wait for sync pattern */
+		break;
+	case 2: /* T2: wait for response to disconnect */
+		break;
+	}
+}
+
+static const struct osmo_fsm_state v110_ta_states[] = {
+	[V110_TA_S_IDLE_READY] = {
+		.name = "IDLE_READY",
+		.in_event_mask = S(V110_TA_E_TX_FRAME_RTS),
+		.out_state_mask = S(V110_TA_S_CON_TA_LINE),
+		.action = v110fsm_ta_idle_ready,
+		.ontenter = v110fsm_ta_idle_ready_onenter,
+	},
+	[V110_TA_S_CON_TA_LINE] = {
+		.name = "CONNECT_TA_TO_LINE",
+		.in_event_mask = S(V110_TA_E_TX_FRAME_RTS),
+		.out_state_mask = S(V110_TA_S_IDLE_READY) |
+				  S(V110_TA_S_DATA_TRANSFER),
+		.action = v110fsm_ta_connect_ta_to_line,
+		.ontenter = v110fsm_ta_connect_ta_to_line_onenter,
+	},
+	[V110_TA_S_DATA_TRANSFER] = {
+		.name = "DATA_TRANSFER",
+		.in_event_mask = ,
+		.out_state_mask = ,
+		.action = v110fsm_ta_data_transfer,
+		.onenter = v110fsm_ta_data_transfer_onenter,
+	},
+};
+
+static struct osmo_fsm osmo_v110_ta_fsm = {
+	.name = "V110-TA",
+	.states = v110_ta_states,
+	.num_states = ARRAY_SIZE(v110_ta_states),
+	.allstate_event_mask = FIXME,
+	.allstate_action = FIXME,
+	.timer_cb = v110_ta_timer_cb,
+	.log_subsys = FIXME,
+	.event_names = v110_ta_event_names,
+};