| /*! \file v110_ta.c |
| * TA (Terminal Adapter) implementation as per ITU-T V.110. */ |
| /* |
| * (C) 2022 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| * |
| * Initial (Work-in-Progress) implementation by Harald Welte, |
| * completed and co-authored by Vadim Yanitskiy. |
| * |
| * All Rights Reserved |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * 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 <stdbool.h> |
| #include <stdint.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/bits.h> |
| #include <osmocom/core/tdef.h> |
| #include <osmocom/core/fsm.h> |
| |
| #include <osmocom/isdn/v110.h> |
| #include <osmocom/isdn/v110_ta.h> |
| |
| #define S(x) (1 << (x)) |
| |
| #define V24_FLAGMASK_IS_ON(flags, circuit) \ |
| (((flags) & S(circuit)) != 0) |
| |
| #define V24_FLAGMASK_IS_OFF(flags, circuit) \ |
| (((flags) & S(circuit)) == 0) |
| |
| #define V24_FLAGMASK_SET_ON(flags, circuit) \ |
| (flags) |= S(circuit) |
| |
| #define V24_FLAGMASK_SET_OFF(flags, circuit) \ |
| (flags) &= ~S(circuit) |
| |
| /* inverse logic: ON = binary 0; OFF = binary 1 */ |
| #define V110_SX_BIT_ON 0 |
| #define V110_SX_BIT_OFF 1 |
| |
| const struct value_string osmo_v110_ta_circuit_names[] = { |
| { OSMO_V110_TA_C_105, "105/RTS" }, |
| { OSMO_V110_TA_C_106, "106/CTS" }, |
| { OSMO_V110_TA_C_107, "107/DSR" }, |
| { OSMO_V110_TA_C_108, "108/DTR" }, |
| { OSMO_V110_TA_C_109, "109/DCD" }, |
| { OSMO_V110_TA_C_133, "133" }, |
| { 0, NULL } |
| }; |
| |
| const struct value_string osmo_v110_ta_circuit_descs[] = { |
| { OSMO_V110_TA_C_105, "Request to Send" }, |
| { OSMO_V110_TA_C_106, "Clear to Send" }, |
| { OSMO_V110_TA_C_107, "Data Set Ready" }, |
| { OSMO_V110_TA_C_108, "Data Terminal Ready" }, |
| { OSMO_V110_TA_C_109, "Data Carrier Detect" }, |
| { OSMO_V110_TA_C_133, "Ready for receiving" }, |
| { 0, NULL } |
| }; |
| |
| static const struct osmo_tdef v110_ta_tdef[] = { |
| { .T = OSMO_V110_TA_TIMER_X1, |
| .unit = OSMO_TDEF_MS, .default_val = 3000, /* suggested in 7.1.5 e) */ |
| .desc = "ITU-T V.110 7.1.5 Loss of frame synchronization: sync recovery timer" }, |
| { .T = OSMO_V110_TA_TIMER_T1, |
| .unit = OSMO_TDEF_MS, .default_val = 10000, /* suggested in 7.1.2.2 */ |
| .desc = "ITU-T V.110 7.1.2 Connect TA to line: sync establishment timer" }, |
| { .T = OSMO_V110_TA_TIMER_T2, |
| .unit = OSMO_TDEF_MS, .default_val = 5000, /* suggested in 7.1.4.1 */ |
| .desc = "ITU-T V.110 7.1.4 Disconnect mode: disconnect confirmation timer" }, |
| { /* end of list */ } |
| }; |
| |
| /********************************************************************************* |
| * V.110 TERMINAL ADAPTER FSM |
| *********************************************************************************/ |
| |
| enum v110_ta_fsm_state { |
| V110_TA_ST_IDLE_READY, /* 7.1.1 Idle (or ready) state */ |
| V110_TA_ST_CON_TA_TO_LINE, /* 7.1.2 Connect TA to line state */ |
| V110_TA_ST_DATA_TRANSFER, /* 7.1.3 Data transfer state */ |
| V110_TA_ST_DISCONNECTING, /* 7.1.4 Disconnect mode */ |
| V110_TA_ST_RESYNCING, /* 7.1.5 Re-synchronizing state */ |
| }; |
| |
| enum v110_ta_fsm_event { |
| V110_TA_EV_RX_FRAME_IND, /* a V.110 frame was received by the lower layer */ |
| V110_TA_EV_TX_FRAME_RTS, /* a V.110 frame is to be sent by the lower layer */ |
| V110_TA_EV_V24_STATUS_CHG, /* V.24 flag-mask has been updated by TE */ |
| V110_TA_EV_SYNC_IND, /* the lower layer has synchronized to the frame clock */ |
| V110_TA_EV_DESYNC_IND, /* the lower layer has lost frame clock synchronization */ |
| V110_TA_EV_TIMEOUT, /* generic event for handling a timeout condition */ |
| }; |
| |
| static const struct value_string v110_ta_fsm_event_names[] = { |
| { V110_TA_EV_RX_FRAME_IND, "RX_FRAME_IND" }, |
| { V110_TA_EV_TX_FRAME_RTS, "TX_FRAME_RTS" }, |
| { V110_TA_EV_V24_STATUS_CHG, "V24_STATUS_CHG" }, |
| { V110_TA_EV_SYNC_IND, "SYNC_IND" }, |
| { V110_TA_EV_DESYNC_IND, "DESYNC_IND" }, |
| { V110_TA_EV_TIMEOUT, "TIMEOUT" }, |
| { 0, NULL } |
| }; |
| |
| enum v110_ta_d_bit_mode { |
| V110_TA_DBIT_M_ALL_ZERO = 0, /* set all bits to binary '0' */ |
| V110_TA_DBIT_M_ALL_ONE = 1, /* set all bits to binary '1' */ |
| V110_TA_DBIT_M_FORWARD, /* forward D-bits to/from DTE */ |
| }; |
| |
| struct v110_ta_state { |
| /*! V.24 status flags shared between DTE (user) and DCE (TA, us) */ |
| unsigned int v24_flags; |
| struct { |
| /* what kind of D-bits to transmit in V.110 frames */ |
| enum v110_ta_d_bit_mode d_bit_mode; |
| /* what to put in S-bits of transmitted V.110 frames */ |
| ubit_t s_bits; |
| /* what to put in X-bits of transmitted V.110 frames */ |
| ubit_t x_bits; |
| } tx; |
| struct { |
| enum v110_ta_d_bit_mode d_bit_mode; |
| } rx; |
| }; |
| |
| struct osmo_v110_ta { |
| const char *name; |
| struct osmo_tdef *Tdefs; |
| struct osmo_fsm_inst *fi; |
| struct osmo_v110_ta_cfg *cfg; |
| struct v110_ta_state state; |
| }; |
| |
| static inline bool v110_df_x_bits_are(const struct osmo_v110_decoded_frame *df, ubit_t cmp) |
| { |
| return (df->x_bits[0] == cmp) && (df->x_bits[1] == cmp); |
| } |
| |
| static inline bool v110_df_s_bits_are(const struct osmo_v110_decoded_frame *df, ubit_t cmp) |
| { |
| /* ITU-T Table 2/V.110 (see also 5.1.2.3) defines the following S-bits: |
| * S1, S3, S4, S6, S8, S9 (6 bits total). However, fr->s_bits[] contains |
| * 9 (MAX_S_BITS) bits, including the undefined bits S2, S5, S7. |
| * Hence we must skip those undefined bits. */ |
| static const uint8_t sbit_map[] = { 0, 2, 3, 5, 7, 8 }; |
| |
| for (unsigned int i = 0; i < ARRAY_SIZE(sbit_map); i++) { |
| uint8_t idx = sbit_map[i]; |
| if (df->s_bits[idx] != cmp) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static inline bool v110_df_d_bits_are(const struct osmo_v110_decoded_frame *df, ubit_t cmp) |
| { |
| for (unsigned int i = 0; i < MAX_D_BITS; i++) { |
| if (df->d_bits[i] != cmp) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* handle one V.110 frame and forward user bits to the application */ |
| static void v110_ta_handle_frame(const struct osmo_v110_ta *ta, |
| const struct osmo_v110_decoded_frame *df) |
| { |
| const struct osmo_v110_ta_cfg *cfg = ta->cfg; |
| const struct v110_ta_state *ts = &ta->state; |
| ubit_t user_bits[MAX_D_BITS]; |
| int num_user_bits; |
| int rc; |
| |
| switch (ts->rx.d_bit_mode) { |
| case V110_TA_DBIT_M_ALL_ZERO: |
| case V110_TA_DBIT_M_ALL_ONE: |
| /* generate as many user bits as needed for the configured rate */ |
| num_user_bits = osmo_v110_sync_ra1_get_user_data_chunk_bitlen(cfg->rate); |
| OSMO_ASSERT(num_user_bits > 0); |
| /* set them all to binary '0' or binary '1' */ |
| memset(&user_bits[0], (int)ts->rx.d_bit_mode, num_user_bits); |
| cfg->rx_cb(cfg->priv, &user_bits[0], num_user_bits); |
| break; |
| case V110_TA_DBIT_M_FORWARD: |
| rc = osmo_v110_sync_ra1_ir_to_user(cfg->rate, &user_bits[0], sizeof(user_bits), df); |
| if (rc > 0) |
| cfg->rx_cb(cfg->priv, &user_bits[0], rc); |
| /* XXX else: indicate an error somehow? */ |
| break; |
| } |
| } |
| |
| /* build one V.110 frame to transmit */ |
| static void v110_ta_build_frame(const struct osmo_v110_ta *ta, |
| struct osmo_v110_decoded_frame *df) |
| { |
| const struct osmo_v110_ta_cfg *cfg = ta->cfg; |
| const struct v110_ta_state *ts = &ta->state; |
| ubit_t user_bits[MAX_D_BITS]; |
| int num_user_bits; |
| int rc; |
| |
| /* E-bits (E1/E2/E3 may be overwritten below) */ |
| memset(df->e_bits, 1, sizeof(df->e_bits)); |
| /* S-bits */ |
| memset(df->s_bits, ts->tx.s_bits, sizeof(df->s_bits)); |
| /* X-bits */ |
| memset(df->x_bits, ts->tx.x_bits, sizeof(df->x_bits)); |
| |
| /* D-bits */ |
| switch (ts->tx.d_bit_mode) { |
| case V110_TA_DBIT_M_ALL_ZERO: |
| case V110_TA_DBIT_M_ALL_ONE: |
| /* set them all to binary '0' or binary '1' */ |
| memset(df->d_bits, (int)ts->tx.d_bit_mode, sizeof(df->d_bits)); |
| break; |
| case V110_TA_DBIT_M_FORWARD: |
| /* how many user bits to retrieve */ |
| num_user_bits = osmo_v110_sync_ra1_get_user_data_chunk_bitlen(cfg->rate); |
| OSMO_ASSERT(num_user_bits > 0); |
| /* retrieve user bits from the application */ |
| cfg->tx_cb(cfg->priv, &user_bits[0], num_user_bits); |
| /* convert user bits to intermediate rate (store to df) */ |
| rc = osmo_v110_sync_ra1_user_to_ir(cfg->rate, df, &user_bits[0], num_user_bits); |
| OSMO_ASSERT(rc == 0); |
| break; |
| } |
| } |
| |
| static void v110_ta_flags_update(struct osmo_v110_ta *ta, unsigned int v24_flags) |
| { |
| struct osmo_v110_ta_cfg *cfg = ta->cfg; |
| |
| if (ta->state.v24_flags == v24_flags) |
| return; |
| if (cfg->status_update_cb != NULL) |
| cfg->status_update_cb(cfg->priv, v24_flags); |
| ta->state.v24_flags = v24_flags; |
| } |
| |
| static const struct osmo_tdef_state_timeout v110_ta_fsm_timeouts[32] = { |
| [V110_TA_ST_RESYNCING] = { .T = OSMO_V110_TA_TIMER_X1 }, |
| [V110_TA_ST_CON_TA_TO_LINE] = { .T = OSMO_V110_TA_TIMER_T1 }, |
| [V110_TA_ST_DISCONNECTING] = { .T = OSMO_V110_TA_TIMER_T2 }, |
| }; |
| |
| #define v110_ta_fsm_state_chg(state) \ |
| osmo_tdef_fsm_inst_state_chg(fi, state, \ |
| v110_ta_fsm_timeouts, \ |
| ((struct osmo_v110_ta *)(fi->priv))->Tdefs, \ |
| 0) |
| |
| /* ITU-T V.110 Section 7.1.1 */ |
| static void v110_ta_fsm_idle_ready_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| /* 7.1.1.2 During the idle (or ready) state the TA will transmit continuous binary 1s into the B-channel */ |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_ALL_ONE; /* circuit 103: continuous binary '1' */ |
| ts->tx.s_bits = V110_SX_BIT_OFF; /* OFF is binary '1' */ |
| ts->tx.x_bits = V110_SX_BIT_OFF; /* OFF is binary '1' */ |
| |
| /* 7.1.1.3 During the idle (or ready) state the TA (DCE) will transmit the following toward the DTE: */ |
| /* - circuit 104: continuous binary '1' */ |
| ts->rx.d_bit_mode = V110_TA_DBIT_M_ALL_ONE; |
| /* - circuits 107, 106, 109 = OFF */ |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_106); |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_107); |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_109); |
| v110_ta_flags_update(ta, v24_flags); |
| } |
| |
| /* ITU-T V.110 Section 7.1.1 */ |
| static void v110_ta_fsm_idle_ready(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| |
| switch (event) { |
| case V110_TA_EV_V24_STATUS_CHG: |
| /* 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_V110_TA_C_108)) { |
| /* 7.12.2: Start timer T1 when switching to CON_TA_LINE */ |
| v110_ta_fsm_state_chg(V110_TA_ST_CON_TA_TO_LINE); |
| } |
| break; |
| case V110_TA_EV_RX_FRAME_IND: |
| v110_ta_handle_frame(ta, (const struct osmo_v110_decoded_frame *)data); |
| break; |
| case V110_TA_EV_TX_FRAME_RTS: |
| v110_ta_build_frame(ta, (struct osmo_v110_decoded_frame *)data); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| /* ITU-T V.110 Section 7.1.2 */ |
| static void v110_ta_fsm_connect_ta_to_line_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| |
| /* 7.1.2.1 Switching to the data mode causes the TA to transmit the following towards the ISDN: */ |
| /* a) frame synchronization pattern as described in 5.1.3.1 and 5.2.1 (done by the API user) */ |
| /* b) circuit 103: continuous binary '1' */ |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_ALL_ONE; |
| /* c) status bits S = OFF and X = OFF */ |
| ts->tx.s_bits = V110_SX_BIT_OFF; /* OFF is binary '1' */ |
| ts->tx.x_bits = V110_SX_BIT_OFF; /* OFF is binary '1' */ |
| |
| /* 7.1.2.2 ... the receiver in the TA will begin to search for the frame synchronization |
| * pattern in the received bit stream (see 5.1.3.1 and 5.2.1) and start timer T1. */ |
| OSMO_ASSERT(fi->T == OSMO_V110_TA_TIMER_T1); |
| } |
| |
| /* ITU-T V.110 Section 7.1.2 */ |
| static void v110_ta_fsm_connect_ta_to_line(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| |
| switch (event) { |
| case V110_TA_EV_V24_STATUS_CHG: |
| /* If circuit 108 is OFF, we go back to IDLE/READY */ |
| if (V24_FLAGMASK_IS_OFF(ts->v24_flags, OSMO_V110_TA_C_108)) |
| v110_ta_fsm_state_chg(V110_TA_ST_IDLE_READY); |
| break; |
| case V110_TA_EV_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). */ |
| OSMO_ASSERT(V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V110_TA_C_108)); |
| ts->tx.s_bits = V110_SX_BIT_ON; |
| ts->tx.x_bits = V110_SX_BIT_ON; |
| break; |
| case V110_TA_EV_RX_FRAME_IND: |
| { |
| const struct osmo_v110_decoded_frame *df = data; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| /* 7.1.2.4 When the receiver recognizes that the status of bits S and X are ON */ |
| if (v110_df_s_bits_are(df, V110_SX_BIT_ON) && |
| v110_df_x_bits_are(df, V110_SX_BIT_ON)) { |
| /* ... it will perform the following functions: */ |
| /* a) Turn ON circuit 107 toward the DTE and stop timer T1 */ |
| V24_FLAGMASK_SET_ON(v24_flags, OSMO_V110_TA_C_107); |
| osmo_timer_del(&fi->timer); |
| /* 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(v24_flags, OSMO_V110_TA_C_109); |
| ts->rx.d_bit_mode = V110_TA_DBIT_M_FORWARD; |
| /* d) After an interval of N bits (see 6.3), it will turn ON circuit 106. */ |
| V24_FLAGMASK_SET_ON(v24_flags, OSMO_V110_TA_C_106); |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_FORWARD; |
| v110_ta_flags_update(ta, v24_flags); |
| /* Circuit 106 transitioning from OFF to ON will cause the transmitted data to |
| * transition from binary 1 to the data mode. */ |
| v110_ta_fsm_state_chg(V110_TA_ST_DATA_TRANSFER); |
| } |
| |
| v110_ta_handle_frame(ta, df); |
| break; |
| } |
| case V110_TA_EV_TX_FRAME_RTS: |
| v110_ta_build_frame(ta, (struct osmo_v110_decoded_frame *)data); |
| break; |
| case V110_TA_EV_TIMEOUT: |
| v110_ta_fsm_state_chg(V110_TA_ST_IDLE_READY); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| /* ITU-T V.110 Section 7.1.3 */ |
| static void v110_ta_fsm_data_transfer_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| /* 7.1.3.1 While in the data transfer state, the following circuit conditions exist: |
| * a): 105, 107, 108, and 109 are in the ON condition */ |
| /* XXX: OSMO_ASSERT(V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V110_TA_C_105)); */ |
| V24_FLAGMASK_SET_ON(v24_flags, OSMO_V110_TA_C_107); |
| /* XXX: OSMO_ASSERT(V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V110_TA_C_108)); */ |
| V24_FLAGMASK_SET_ON(v24_flags, OSMO_V110_TA_C_109); |
| /* b) data is being transmitted on circuit 103 and received on circuit 104 */ |
| ts->rx.d_bit_mode = V110_TA_DBIT_M_FORWARD; |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_FORWARD; |
| /* c) circuits 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 (!ta->cfg->flow_ctrl.end_to_end) { |
| /* XXX: OSMO_ASSERT(V24_FLAGMASK_IS_ON(ts->v24_flags, OSMO_V110_TA_C_133)); */ |
| V24_FLAGMASK_SET_ON(v24_flags, OSMO_V110_TA_C_106); |
| } |
| v110_ta_flags_update(ta, v24_flags); |
| |
| /* 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 = V110_SX_BIT_ON; |
| /* 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 (!ta->cfg->flow_ctrl.end_to_end) |
| ts->tx.x_bits = V110_SX_BIT_ON; |
| } |
| |
| /* ITU-T V.110 Section 7.1.3 */ |
| static void v110_ta_fsm_data_transfer(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| |
| /* 7.1.3.3 While in the data transfer state: */ |
| /* a) the S status bits shall *not* be mapped to/from the interchange circuits */ |
| /* b) the X status bits shall *not* be mapped according to Table 3, |
| * unless end-to-end flow control is implemented */ |
| /* TODO: if (ta->cfg->flow_ctrl.end_to_end) { ... } */ |
| |
| switch (event) { |
| case V110_TA_EV_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_ON(ts->v24_flags, OSMO_V110_TA_C_108)) |
| break; |
| v110_ta_fsm_state_chg(V110_TA_ST_DISCONNECTING); |
| break; |
| case V110_TA_EV_DESYNC_IND: |
| v110_ta_fsm_state_chg(V110_TA_ST_RESYNCING); |
| break; |
| case V110_TA_EV_TX_FRAME_RTS: |
| v110_ta_build_frame(ta, (struct osmo_v110_decoded_frame *)data); |
| break; |
| case V110_TA_EV_RX_FRAME_IND: |
| { |
| const struct osmo_v110_decoded_frame *df = data; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| /* 7.1.4.2 ... this TA will recognize the transition of the status bits S from |
| * ON to OFF and the data bits from data to binary 0 as a disconnect request */ |
| if (v110_df_s_bits_are(df, V110_SX_BIT_OFF) && v110_df_d_bits_are(df, 0)) { |
| /* ... and it will turn OFF circuits 107 and 109. */ |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_107); |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_109); |
| v110_ta_flags_update(ta, v24_flags); |
| /* DTE should respond by turning OFF circuit 108 */ |
| break; /* XXX: shall we forward D-bits to DTE anyway? */ |
| } |
| |
| v110_ta_handle_frame(ta, df); |
| break; |
| } |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| /* ITU-T V.110 Section 7.1.4 */ |
| static void v110_ta_fsm_disconnect_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| /* 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. This will cause the following to occur: */ |
| /* a) the status bits S in the frame toward ISDN will turn OFF, status bits X are kept ON */ |
| ts->tx.s_bits = V110_SX_BIT_OFF; |
| /* b) circuit 106 will be turned OFF */ |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_106); |
| v110_ta_flags_update(ta, v24_flags); |
| /* c) the data bits in the frame will be set to binary 0. */ |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_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_ASSERT(fi->T == OSMO_V110_TA_TIMER_T2); |
| } |
| |
| /* ITU-T V.110 Section 7.1.4 */ |
| static void v110_ta_fsm_disconnect(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| |
| switch (event) { |
| case V110_TA_EV_V24_STATUS_CHG: |
| break; /* nothing to do */ |
| case V110_TA_EV_TX_FRAME_RTS: |
| v110_ta_build_frame(ta, (struct osmo_v110_decoded_frame *)data); |
| break; |
| case V110_TA_EV_RX_FRAME_IND: |
| { |
| const struct osmo_v110_decoded_frame *df = data; |
| |
| /* 7.1.4.3 The TA at the station that originated the disconnect request will |
| * recognize reception of S = OFF or the loss of framing signals as a disconnect |
| * acknowledgement and turn OFF circuits 107 and 109. */ |
| if (v110_df_s_bits_are(df, V110_SX_BIT_OFF)) { |
| /* circuits 107 and 109 set to off in .onenter() */ |
| v110_ta_fsm_state_chg(V110_TA_ST_IDLE_READY); |
| } |
| |
| v110_ta_handle_frame(ta, df); |
| break; |
| } |
| case V110_TA_EV_DESYNC_IND: |
| case V110_TA_EV_TIMEOUT: |
| /* circuits 107 and 109 set to off in .onenter() */ |
| v110_ta_fsm_state_chg(V110_TA_ST_IDLE_READY); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| /* ITU-T V.110 Section 7.1.5 */ |
| static void v110_ta_fsm_resyncing_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| |
| /* 7.1.5 In the event of loss of frame synchronization, the (local) TA should |
| * attempt to resynchronize as follows: */ |
| /* a) Place circuit 104 in binary 1 condition (passes from the data mode) */ |
| ts->rx.d_bit_mode = V110_TA_DBIT_M_ALL_ONE; |
| /* b) Turn OFF status bit X in the transmitted frame */ |
| ts->tx.x_bits = V110_SX_BIT_OFF; |
| |
| /* guard timeout, see 7.1.5 e) */ |
| OSMO_ASSERT(fi->T == OSMO_V110_TA_TIMER_X1); |
| } |
| |
| /* ITU-T V.110 Section 7.1.5 */ |
| static void v110_ta_fsm_resyncing(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_v110_ta *ta = (struct osmo_v110_ta *)fi->priv; |
| struct v110_ta_state *ts = &ta->state; |
| unsigned int v24_flags = ta->state.v24_flags; |
| |
| switch (event) { |
| case V110_TA_EV_V24_STATUS_CHG: |
| break; /* TODO: handle circuit 108 being set to OFF? */ |
| case V110_TA_EV_TX_FRAME_RTS: |
| v110_ta_build_frame(ta, (struct osmo_v110_decoded_frame *)data); |
| break; |
| case V110_TA_EV_SYNC_IND: |
| /* f) If resynchronization is achieved, the local TA should turn ON status bit X */ |
| ts->tx.x_bits = V110_SX_BIT_ON; |
| v110_ta_fsm_state_chg(V110_TA_ST_DATA_TRANSFER); |
| break; |
| case V110_TA_EV_TIMEOUT: |
| /* e) If after an interval of X1 seconds the local TA cannot attain synchronization, |
| * it should send a disconnect request by turning OFF all of the status bits for several |
| * (at least three) frames with data bits set to binary 0 and then disconnect by turning |
| * OFF circuit 107 and transferring to the disconnected mode as discussed in 7.1.4.2. */ |
| ts->tx.s_bits = V110_SX_BIT_OFF; |
| ts->tx.x_bits = V110_SX_BIT_OFF; |
| ts->tx.d_bit_mode = V110_TA_DBIT_M_ALL_ZERO; |
| /* TODO: actually Tx those frames (delay state transition) */ |
| V24_FLAGMASK_SET_OFF(v24_flags, OSMO_V110_TA_C_107); |
| v110_ta_flags_update(ta, v24_flags); |
| v110_ta_fsm_state_chg(V110_TA_ST_DISCONNECTING); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| static int v110_ta_timer_cb(struct osmo_fsm_inst *fi) |
| { |
| osmo_fsm_inst_dispatch(fi, V110_TA_EV_TIMEOUT, NULL); |
| return 0; |
| } |
| |
| static const struct osmo_fsm_state v110_ta_states[] = { |
| [V110_TA_ST_IDLE_READY] = { |
| .name = "IDLE_READY", |
| .in_event_mask = S(V110_TA_EV_V24_STATUS_CHG) |
| | S(V110_TA_EV_TX_FRAME_RTS) |
| | S(V110_TA_EV_RX_FRAME_IND), |
| .out_state_mask = S(V110_TA_ST_IDLE_READY) |
| | S(V110_TA_ST_CON_TA_TO_LINE), |
| .action = &v110_ta_fsm_idle_ready, |
| .onenter = &v110_ta_fsm_idle_ready_onenter, |
| }, |
| [V110_TA_ST_CON_TA_TO_LINE] = { |
| .name = "CONNECT_TA_TO_LINE", |
| .in_event_mask = S(V110_TA_EV_V24_STATUS_CHG) |
| | S(V110_TA_EV_TIMEOUT) |
| | S(V110_TA_EV_SYNC_IND) |
| | S(V110_TA_EV_TX_FRAME_RTS) |
| | S(V110_TA_EV_RX_FRAME_IND), |
| .out_state_mask = S(V110_TA_ST_DATA_TRANSFER) |
| | S(V110_TA_ST_IDLE_READY), |
| .action = &v110_ta_fsm_connect_ta_to_line, |
| .onenter = &v110_ta_fsm_connect_ta_to_line_onenter, |
| }, |
| [V110_TA_ST_DATA_TRANSFER] = { |
| .name = "DATA_TRANSFER", |
| .in_event_mask = S(V110_TA_EV_V24_STATUS_CHG) |
| | S(V110_TA_EV_DESYNC_IND) |
| | S(V110_TA_EV_TX_FRAME_RTS) |
| | S(V110_TA_EV_RX_FRAME_IND), |
| .out_state_mask = S(V110_TA_ST_RESYNCING) |
| | S(V110_TA_ST_DISCONNECTING), |
| .action = &v110_ta_fsm_data_transfer, |
| .onenter = &v110_ta_fsm_data_transfer_onenter, |
| }, |
| [V110_TA_ST_DISCONNECTING] = { |
| .name = "DISCONNECTING", |
| .in_event_mask = S(V110_TA_EV_V24_STATUS_CHG) |
| | S(V110_TA_EV_TIMEOUT) |
| | S(V110_TA_EV_TX_FRAME_RTS) |
| | S(V110_TA_EV_RX_FRAME_IND) |
| | S(V110_TA_EV_DESYNC_IND), |
| .out_state_mask = S(V110_TA_ST_IDLE_READY), |
| .action = &v110_ta_fsm_disconnect, |
| .onenter = &v110_ta_fsm_disconnect_onenter, |
| }, |
| [V110_TA_ST_RESYNCING] = { |
| .name = "RESYNCING", |
| .in_event_mask = S(V110_TA_EV_V24_STATUS_CHG) |
| | S(V110_TA_EV_TIMEOUT) |
| | S(V110_TA_EV_TX_FRAME_RTS) |
| | S(V110_TA_EV_SYNC_IND), |
| .out_state_mask = S(V110_TA_ST_IDLE_READY) |
| | S(V110_TA_ST_DATA_TRANSFER), |
| .action = &v110_ta_fsm_resyncing, |
| .onenter = &v110_ta_fsm_resyncing_onenter, |
| }, |
| }; |
| |
| static struct osmo_fsm osmo_v110_ta_fsm = { |
| .name = "V110-TA", |
| .states = v110_ta_states, |
| .num_states = ARRAY_SIZE(v110_ta_states), |
| .timer_cb = v110_ta_timer_cb, |
| .log_subsys = DLGLOBAL, |
| .event_names = v110_ta_fsm_event_names, |
| }; |
| |
| static __attribute__((constructor)) void on_dso_load(void) |
| { |
| OSMO_ASSERT(osmo_fsm_register(&osmo_v110_ta_fsm) == 0); |
| } |
| |
| /*! Allocate a V.110 TA (Terminal Adapter) instance. |
| * \param[in] ctx parent talloc context. |
| * \param[in] name name of the TA instance. |
| * \param[in] cfg initial configuration of the TA instance. |
| * \returns pointer to allocated TA instance; NULL on error. */ |
| struct osmo_v110_ta *osmo_v110_ta_alloc(void *ctx, const char *name, |
| const struct osmo_v110_ta_cfg *cfg) |
| { |
| struct osmo_v110_ta *ta; |
| |
| OSMO_ASSERT(cfg != NULL); |
| OSMO_ASSERT(cfg->rx_cb != NULL); |
| OSMO_ASSERT(cfg->tx_cb != NULL); |
| |
| /* local (TE-TA) flow control is not implemented */ |
| if (cfg->flow_ctrl.local != OSMO_V110_LOCAL_FLOW_CTRL_NONE) { |
| LOGP(DLGLOBAL, LOGL_ERROR, "Local (TE-TA) flow control is not implemented\n"); |
| return NULL; |
| } |
| |
| ta = talloc_zero(ctx, struct osmo_v110_ta); |
| if (ta == NULL) |
| return NULL; |
| |
| ta->name = talloc_strdup(ta, name); |
| ta->cfg = talloc_memdup(ta, cfg, sizeof(*cfg)); |
| if (ta->name == NULL || ta->cfg == NULL) |
| goto exit_free; |
| |
| ta->Tdefs = talloc_memdup(ta, v110_ta_tdef, sizeof(v110_ta_tdef)); |
| if (ta->Tdefs == NULL) |
| goto exit_free; |
| osmo_tdefs_reset(ta->Tdefs); /* apply default values */ |
| |
| ta->fi = osmo_fsm_inst_alloc(&osmo_v110_ta_fsm, ta, ta, LOGL_DEBUG, name); |
| if (ta->fi == NULL) |
| goto exit_free; |
| |
| /* perform a loop transition to init the internal state */ |
| osmo_fsm_inst_state_chg(ta->fi, V110_TA_ST_IDLE_READY, 0, 0); |
| |
| return ta; |
| |
| exit_free: |
| if (ta->fi != NULL) |
| osmo_fsm_inst_free(ta->fi); |
| talloc_free(ta); |
| return NULL; |
| } |
| |
| /*! Release memory taken by the given V.110 TA instance. |
| * \param[in] ta TA instance to be free()d. */ |
| void osmo_v110_ta_free(struct osmo_v110_ta *ta) |
| { |
| if (ta == NULL) |
| return; |
| if (ta->fi != NULL) |
| osmo_fsm_inst_free(ta->fi); |
| talloc_free(ta); /* also free()s name and cfg */ |
| } |
| |
| /*! Configure a timer of the given V.110 TA instance. |
| * \param[in] ta TA instance to be configured. |
| * \param[in] timer a timer to be configured. |
| * \param[in] val_ms the new timeout value to set (in milliseconds). |
| * \returns 0 in case of success; negative on error. */ |
| int osmo_v110_ta_set_timer_val_ms(struct osmo_v110_ta *ta, |
| enum osmo_v110_ta_timer timer, |
| unsigned long val_ms) |
| { |
| return osmo_tdef_set(ta->Tdefs, (int)timer, val_ms, OSMO_TDEF_MS); |
| } |
| |
| /*! Feed a [decoded] V.110 frame into the given TA instance. |
| * |
| * This function, like its _out counterpart, is intended to be used by the lower layers |
| * receiving V.110 frames over some medium. The caller of this function is responsible |
| * for finding the synchronization pattern (if needed), aligning to the frame boundaries, |
| * and decoding frames using osmo_v110_decode_frame() or osmo_csd_*_decode_frame(). |
| * |
| * Bits E1/E2/E3 are expected to be set by the caller (if not being transmitted |
| * over the medium) in accordance with the configured synchronous user rate. |
| * |
| * Bits D1..D48 are passed to the bit rate adaption function RA1. The resulting output |
| * is then passed to the upper layer (application) via the configured .rx_cb(). Though, |
| * in certain states of the TA's FSM, bits D1..D48 are ignored and the upper layer |
| * gets a sequence of binary '0' or '1'. |
| * |
| * \param[in] ta TA instance to feed the given frame into. |
| * \param[in] in pointer to a [decoded] V.110 frame. |
| * \returns 0 in case of success; negative on error. */ |
| int osmo_v110_ta_frame_in(struct osmo_v110_ta *ta, const struct osmo_v110_decoded_frame *in) |
| { |
| return osmo_fsm_inst_dispatch(ta->fi, V110_TA_EV_RX_FRAME_IND, (void *)in); |
| } |
| |
| /*! Pull a [decoded] V.110 frame out of the given TA instance. |
| * |
| * This function, like its _in counterpart, is intended to be used by the lower layers |
| * transmitting V.110 frames over some medium. The caller of this function is responsible |
| * for encoding the output frame using osmo_v110_encode_frame() or osmo_csd_*_encode_frame(). |
| * |
| * Bits E1/E2/E3 are set in accordance with the configured synchronous user rate. |
| * Bits E4/E5/E6/E7 are unconditionally set to binary '1'. |
| * |
| * Bits D1..D48 are set depending on the state of TA's FSM: |
| * |
| * - In data transfer mode, the user bits are obtained from the upper layer (application) |
| * via the configured .tx_cb(), and then passed to the bit rate adaption function RA1, |
| * which generates bits D1..D48. |
| * - In other modes, bits D1..D48 are all set to binary '0' or '1'. |
| * |
| * \param[in] ta TA instance to pull a frame from. |
| * \param[out] out where to store a [decoded] V.110 frame. |
| * \returns 0 in case of success; negative on error. */ |
| int osmo_v110_ta_frame_out(struct osmo_v110_ta *ta, struct osmo_v110_decoded_frame *out) |
| { |
| return osmo_fsm_inst_dispatch(ta->fi, V110_TA_EV_TX_FRAME_RTS, (void *)out); |
| } |
| |
| /*! Indicate a synchronization establishment event. |
| * |
| * This function is intended to be called when the lower layer |
| * achieves synchronization to the frame clock. |
| * |
| * \param[in] ta TA instance to indicate the event to. |
| * \returns 0 in case of success; negative on error. */ |
| int osmo_v110_ta_sync_ind(struct osmo_v110_ta *ta) |
| { |
| return osmo_fsm_inst_dispatch(ta->fi, V110_TA_EV_SYNC_IND, NULL); |
| } |
| |
| /*! Indicate a synchronization loss event. |
| * |
| * This function is intended to be called when the lower layer |
| * experiences a loss of synchronization with the frame clock. |
| * |
| * \param[in] ta TA instance to indicate the event to. |
| * \returns 0 in case of success; negative on error. */ |
| int osmo_v110_ta_desync_ind(struct osmo_v110_ta *ta) |
| { |
| return osmo_fsm_inst_dispatch(ta->fi, V110_TA_EV_DESYNC_IND, NULL); |
| } |
| |
| /*! Get the V.24 status bit-mask of the given TA instance. |
| * \param[in] ta TA instance to get the circuit bit-mask. |
| * \returns bitmask of OSMO_V110_TA_C_*. */ |
| unsigned int osmo_v110_ta_get_status(const struct osmo_v110_ta *ta) |
| { |
| return ta->state.v24_flags; |
| } |
| |
| /*! Set the V.24 status bit-mask of the given TA instance. |
| * \param[in] ta TA instance to update the circuit state. |
| * \param[in] status bit-mask of OSMO_V110_TA_C_*. |
| * \returns 0 on success; negative on error. */ |
| static int v110_ta_set_status(struct osmo_v110_ta *ta, unsigned int status) |
| { |
| const unsigned int old_status = ta->state.v24_flags; |
| int rc = 0; |
| |
| ta->state.v24_flags = status; |
| if (status != old_status) |
| rc = osmo_fsm_inst_dispatch(ta->fi, V110_TA_EV_V24_STATUS_CHG, NULL); |
| |
| return rc; |
| } |
| |
| /*! Get state of a V.24 circuit of the given TA instance. |
| * \param[in] ta TA instance to get the circuit state. |
| * \param[in] circuit a V.24 circuit, one of OSMO_V110_TA_C_*. |
| * \returns circuit state: active (true) or inactive (false). */ |
| bool osmo_v110_ta_get_circuit(const struct osmo_v110_ta *ta, |
| enum osmo_v110_ta_circuit circuit) |
| { |
| return V24_FLAGMASK_IS_ON(ta->state.v24_flags, circuit); |
| } |
| |
| /*! Activate/deactivate a V.24 circuit of the given TA instance. |
| * \param[in] ta TA instance to update the circuit state. |
| * \param[in] circuit a V.24 circuit, one of OSMO_V110_TA_C_* (DTE->DCE). |
| * \param[in] active activate (true) or deactivate (false) the circuit. |
| * \returns 0 on success; negative on error. */ |
| int osmo_v110_ta_set_circuit(struct osmo_v110_ta *ta, |
| enum osmo_v110_ta_circuit circuit, bool active) |
| { |
| unsigned int status = ta->state.v24_flags; |
| |
| /* permit setting only DTE->DCE circuits */ |
| switch (circuit) { |
| case OSMO_V110_TA_C_105: |
| case OSMO_V110_TA_C_108: |
| case OSMO_V110_TA_C_133: |
| break; |
| default: |
| LOGPFSML(ta->fi, LOGL_ERROR, |
| "Setting circuit %s is not permitted (wrong direction?)\n", |
| osmo_v110_ta_circuit_name(circuit)); |
| return -EACCES; |
| } |
| |
| if (active) |
| V24_FLAGMASK_SET_ON(status, circuit); |
| else |
| V24_FLAGMASK_SET_OFF(status, circuit); |
| |
| return v110_ta_set_status(ta, status); |
| } |