| /* Osmocom Software Defined E1 |
| * |
| * (C) 2018 by Harald Welte <laforge@gnumonks.org> |
| * |
| * Implements ITU-T Rec. G.704 Section 2.3 |
| */ |
| |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <string.h> |
| |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/fsm.h> |
| |
| #include "crc4itu.h" |
| #include "osmo_e1f.h" |
| |
| #define S(x) (1 << (x)) |
| |
| /* Frame Alignment Signal (BIT1 may be overwritten with CRC-4) */ |
| #define G704_E1_FAS 0x1B |
| |
| static inline bool is_correct_fas(uint8_t bt) { |
| if ((bt & 0x7F) == G704_E1_FAS) |
| return true; |
| else |
| return false; |
| } |
| |
| /* are we in SMF II (true) or I (false) */ |
| static inline bool is_smf_II(const struct osmo_e1f_tx_state *tx) { |
| if (tx->frame_nr >= 8) |
| return true; |
| return false; |
| } |
| |
| static struct osmo_fsm e1_align_fsm; |
| static void align_fsm_reset(struct osmo_e1f_instance *e1i); |
| |
| static void notify_user(struct osmo_e1f_instance *e1i, enum osmo_e1f_notify_event evt, |
| bool present, void *priv) |
| { |
| if (!e1i->notify_cb) |
| return; |
| e1i->notify_cb(e1i, evt, present, priv); |
| } |
| |
| /*! Initialize a (caller-allocated) Osmocom E1 Instance |
| * \param[inout] e1i E1 Instance to be initialized |
| * \returns 0 on success, negative on error */ |
| int osmo_e1f_instance_init(struct osmo_e1f_instance *e1i, const char *name, e1_notify_cb cb, |
| bool crc4_enabled, void *priv) |
| { |
| int i; |
| |
| e1i->crc4_enabled = crc4_enabled; |
| e1i->notify_cb = cb; |
| e1i->tx.sa4_sa8 = 0x1f; |
| |
| e1i->priv = priv; |
| |
| for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) { |
| struct osmo_e1f_instance_ts *e1t = &e1i->ts[i]; |
| e1t->ts_nr = i; |
| e1t->inst = e1i; |
| INIT_LLIST_HEAD(&e1t->tx.queue); |
| |
| e1t->rx.granularity = 256; |
| } |
| |
| e1i->rx.fi = osmo_fsm_inst_alloc(&e1_align_fsm, NULL, e1i, LOGL_DEBUG, name); |
| if (!e1i->rx.fi) |
| return -1; |
| |
| osmo_e1f_instance_reset(e1i); |
| |
| return 0; |
| } |
| |
| /*! stop E1 timeslot; release any pending rx/tx buffers |
| * \param[in] e1t Timeslot which we are to stop, disable and release buffers */ |
| void osmo_e1f_ts_reset(struct osmo_e1f_instance_ts *e1t) |
| { |
| e1t->tx.underruns = 0; |
| msgb_queue_free(&e1t->tx.queue); |
| |
| e1t->rx.enabled = false; |
| msgb_free(e1t->rx.msg); |
| e1t->rx.msg = NULL; |
| |
| osmo_isdnhdlc_rcv_init(&e1t->rx.hdlc, OSMO_HDLC_F_BITREVERSE); |
| //osmo_isdnhdlc_rcv_init(&e1t->rx.hdlc, 0); |
| osmo_isdnhdlc_out_init(&e1t->tx.hdlc, 0); |
| } |
| |
| /*! stop E1 instance; stops all timeslots and releases any pending rx/tx buffers |
| * \param[in] e1t E1 instance which we are to stop */ |
| void osmo_e1f_instance_reset(struct osmo_e1f_instance *e1i) |
| { |
| int i; |
| |
| align_fsm_reset(e1i); |
| |
| e1i->tx.remote_alarm = false; |
| e1i->tx.crc4_error = false; |
| e1i->tx.frame_nr = 0; |
| e1i->tx.crc4_last_smf = 0; |
| e1i->tx.crc4 = crc4itu_init(); |
| |
| e1i->rx.frame_nr = 0; |
| memset(&e1i->rx.ts0_history, 0, sizeof(e1i->rx.ts0_history)); |
| e1i->rx.ts0_hist_len = 0; |
| e1i->rx.remote_alarm = false; |
| e1i->rx.remote_crc4_error = false; |
| e1i->rx.num_ts0_in_mframe_search = 0; |
| |
| for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) { |
| struct osmo_e1f_instance_ts *e1t = &e1i->ts[i]; |
| osmo_e1f_ts_reset(e1t); |
| } |
| } |
| |
| /*! obtain pointer to TS given by instance + timeslot number |
| * \param[in] e1i E1 intance on which we work |
| * \param[in] ts_nr E1 timeslot number (1..31) |
| * \returns pointer to timeslot; NULL on error */ |
| struct osmo_e1f_instance_ts *osmo_e1f_instance_ts(struct osmo_e1f_instance *e1i, uint8_t ts_nr) |
| { |
| if (ts_nr == 0 || ts_nr >= ARRAY_SIZE(e1i->ts)) |
| return NULL; |
| |
| return &e1i->ts[ts_nr]; |
| } |
| |
| /*! configure an E1 timeslot |
| * \param[in] e1t Timeslot which we are to configure |
| * \param[in] granularity granularity (buffer size) to use on Rx |
| * \param[in] enable enable (true) or disalble (false) receiving on this TS |
| * \param[in] mode the mode for this timeslot (raw or hdlc) |
| * \return 0 on success; negative on error */ |
| int osmo_e1f_ts_config(struct osmo_e1f_instance_ts *e1t, e1_data_cb cb, unsigned int granularity, |
| bool enable, enum osmo_e1f_ts_mode mode) |
| { |
| e1t->rx.data_cb = cb; |
| e1t->rx.enabled = enable; |
| e1t->rx.granularity = granularity; |
| e1t->mode = mode; |
| |
| return 0; |
| } |
| |
| const struct value_string osmo_e1f_notifv_evt_names[] = { |
| { E1_NTFY_EVT_ALIGN_FRAME, "Aligned to Frame" }, |
| { E1_NTFY_EVT_ALIGN_CRC_MFRAME, "Aligned to CRC4-Multiframe" }, |
| { E1_NTFY_EVT_CRC_ERROR, "CRC Error detected (local)" }, |
| { E1_NTFY_EVT_REMOTE_CRC_ERROR, "CRC Error reported (remote)" }, |
| { E1_NTFY_EVT_REMOTE_ALARM, "Remote Alarm condition repoorted" }, |
| { 0, NULL } |
| }; |
| |
| /*********************************************************************** |
| * Transmit Side |
| ***********************************************************************/ |
| |
| /*! Enqueue a message buffer of to-be-transmitted data for a timeslot |
| * \param[in] e1i E1 instance for which to enqueue |
| * \param[in] ts_nr Timeslot number on which data is to be transmitted |
| * \param[in] msg Message buffer storing the to-be-transmitted data |
| * \returns 0 on success; negative in case of error. |
| * |
| * Ownership of \a msg is transferred from caller into this function, but only |
| * in case of successful execution (return 0)! |
| */ |
| void osmo_e1f_ts_enqueue(struct osmo_e1f_instance_ts *e1t, struct msgb *msg) |
| { |
| msgb_enqueue(&e1t->tx.queue, msg); |
| } |
| |
| /* obtain a CRC4 bit for the current frame number */ |
| static uint8_t e1_pull_crc4_bit(struct osmo_e1f_instance *e1i) |
| { |
| /* If CRC-4 is disabled, all CRC bits shall be '1' */ |
| if (e1i->crc4_enabled == 0) { |
| return 0x01; |
| } else { |
| /* CRC is transmitted MSB first */ |
| switch (e1i->tx.frame_nr % 8) { |
| case 0: |
| return (e1i->tx.crc4_last_smf >> 3) & 1; |
| case 2: |
| return (e1i->tx.crc4_last_smf >> 2) & 1; |
| case 4: |
| return (e1i->tx.crc4_last_smf >> 1) & 1; |
| case 6: |
| return (e1i->tx.crc4_last_smf >> 0) & 1; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| } |
| |
| /* pull a single to-be-transmitted byte for TS0 */ |
| static uint8_t e1_pull_ts0(struct osmo_e1f_instance *e1i) |
| { |
| uint8_t ret = 0; |
| |
| /* re-set CRC4 at start of sub-multiframe */ |
| if (e1i->tx.frame_nr == 0 || e1i->tx.frame_nr == 8) { |
| e1i->tx.crc4_last_smf = e1i->tx.crc4; |
| e1i->tx.crc4 = 0; |
| } |
| |
| /* according to Table 5B/G.704 - CRC-4 multiframe structure */ |
| if ((e1i->tx.frame_nr % 2) == 0) { |
| /* FAS */ |
| ret = G704_E1_FAS | (e1_pull_crc4_bit(e1i) << 7); |
| } else { |
| switch (e1i->tx.frame_nr) { |
| case 1: |
| case 3: |
| case 7: |
| ret = 0x40; |
| break; |
| case 5: |
| case 9: |
| case 11: |
| ret = 0xC0; |
| break; |
| case 13: |
| case 15: |
| ret = 0x40; |
| if (!e1i->tx.crc4_error) |
| ret |= 0x80; |
| break; |
| } |
| ret |= e1i->tx.sa4_sa8; |
| if (e1i->tx.remote_alarm) |
| ret |= 0x20; |
| } |
| |
| /* increment frame number modulo 16 */ |
| e1i->tx.frame_nr = (e1i->tx.frame_nr + 1) % 16; |
| |
| return ret; |
| } |
| |
| /* pull a single to-be-transmitted byte for TS1..31 */ |
| static uint8_t e1_pull_tsN(struct osmo_e1f_instance_ts *e1t) |
| { |
| struct msgb *msg = llist_first_entry_or_null(&e1t->tx.queue, struct msgb, list); |
| uint8_t *cur; |
| |
| retry: |
| /* if there's no message to transmit */ |
| if (!msg) { |
| e1t->tx.underruns++; |
| return 0xFF; |
| } |
| if (msgb_length(msg) <= 0) { |
| llist_del(&msg->list); |
| msgb_free(msg); |
| msg = llist_first_entry_or_null(&e1t->tx.queue, struct msgb, list); |
| goto retry; |
| } |
| cur = msgb_pull(msg, 1); |
| return *cur; |
| } |
| |
| /* update the current in-progress CRC4 value with data from \a out_frame */ |
| static void e1_tx_update_crc4(struct osmo_e1f_instance *e1i, const uint8_t *out_frame) |
| { |
| uint8_t ts0; |
| |
| ts0 = out_frame[0]; |
| /* mask off the C bits */ |
| if (is_correct_fas(ts0)) |
| ts0 &= 0x7F; |
| e1i->tx.crc4 = crc4itu_update(e1i->tx.crc4, &ts0, 1); |
| /* add the remaining bytes/bits */ |
| e1i->tx.crc4 = crc4itu_update(e1i->tx.crc4, out_frame+1, ARRAY_SIZE(e1i->ts)-1); |
| } |
| |
| /*! Pull one to-be-transmitted E1 frame (256bits) from the E1 instance |
| * \param e1i E1 instance for which the frame shall be generated |
| * \param[out] out_frame callee-allocated buffer to which function stores 32 bytes |
| * \returns 0 on success, negative on error */ |
| int osmo_e1f_pull_tx_frame(struct osmo_e1f_instance *e1i, uint8_t *out_frame) |
| { |
| int i; |
| |
| /* generate TS0 */ |
| out_frame[0] = e1_pull_ts0(e1i); |
| |
| /* generate TS1..31 */ |
| for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) { |
| struct osmo_e1f_instance_ts *e1t = &e1i->ts[i]; |
| /* get next to-be-transmitted byte from the TS */ |
| out_frame[i] = e1_pull_tsN(e1t); |
| } |
| /* update our CRC4 computation */ |
| e1_tx_update_crc4(e1i, out_frame); |
| |
| return 0; |
| } |
| |
| /*********************************************************************** |
| * Receiver Side |
| ***********************************************************************/ |
| |
| /* According to Figure 2 / ITU-T G.706 */ |
| enum e1_align_state { |
| /* Frame Alignment Search */ |
| E1_AS_SEARCH_FRAME, |
| /* CRC multiframe alignment search */ |
| E1_AS_SEARCH_CRC_MFRAME, |
| /* monitoring for incorrect frame alignment and error performance using CRC */ |
| E1_AS_ALIGNED_CRC_MFRAME, |
| /* no CRC: just frame alignment loss check */ |
| E1_AS_ALIGNED_BASIC, |
| }; |
| |
| enum e1_align_event { |
| /* received a TS0 octet */ |
| E1_AE_RX_TS0, |
| E1_AE_RESET |
| }; |
| |
| static const struct value_string e1_align_evt_names[] = { |
| { E1_AE_RX_TS0, "E1_AE_RX_TS0" }, |
| { E1_AE_RESET, "E1_AE_RESET" }, |
| { 0, NULL } |
| }; |
| |
| /* get a TS0 byte from the history. delta 0 == current, delte 1 == previous, ... */ |
| static uint8_t get_ts0_hist(struct osmo_e1f_instance *e1i, uint8_t delta) |
| { |
| return e1i->rx.ts0_history[((e1i->rx.frame_nr + 16)-delta) % 16]; |
| } |
| |
| /* ITU-T G.706 Section 4.1.1 */ |
| static bool frame_alignment_lost(struct osmo_e1f_instance *e1i) |
| { |
| if (e1i->rx.frame_nr % 2) |
| return false; |
| |
| /* Frame alignment will be assumed to have been lost when three consecutive incorrect |
| * frame alignment signals have been received. */ |
| if (!is_correct_fas(get_ts0_hist(e1i, 0)) && |
| !is_correct_fas(get_ts0_hist(e1i, 2)) && |
| !is_correct_fas(get_ts0_hist(e1i, 4))) |
| return true; |
| else |
| return false; |
| } |
| |
| /* ITU-T G.706 Section 4.1.2 */ |
| static bool frame_alignment_recovered(struct osmo_e1f_instance *e1i) |
| { |
| /* two consecutive FAS with one non-FAS interspersed */ |
| if (is_correct_fas(get_ts0_hist(e1i, 0)) && |
| !is_correct_fas(get_ts0_hist(e1i, 1)) && |
| is_correct_fas(get_ts0_hist(e1i, 2))) |
| return true; |
| else |
| return false; |
| } |
| |
| /* ITU-T G.706 Section 4.2 */ |
| static bool crc_mframe_alignment_achieved(struct osmo_e1f_instance *e1i) |
| { |
| /* if current TS0 byte is FAS, we cannot detect alignment */ |
| if (is_correct_fas(get_ts0_hist(e1i, 0))) |
| return false; |
| if ((get_ts0_hist(e1i, 0) >> 7) == 1 && |
| (get_ts0_hist(e1i, 2) >> 7) == 1 && |
| (get_ts0_hist(e1i, 4) >> 7) == 0 && |
| (get_ts0_hist(e1i, 6) >> 7) == 1 && |
| (get_ts0_hist(e1i, 8) >> 7) == 0 && |
| (get_ts0_hist(e1i, 10) >> 7) == 0) |
| return true; |
| else |
| return false; |
| } |
| |
| /* Get the CRC4 that was received from our Rx TS0 history */ |
| static uint8_t crc4_from_ts0_hist(struct osmo_e1f_instance *e1i, bool smf2) |
| { |
| uint8_t crc = 0; |
| uint8_t offset = 0; |
| |
| if (smf2) |
| offset = 8; |
| |
| crc |= (e1i->rx.ts0_history[0+offset] >> 7) << 3; |
| crc |= (e1i->rx.ts0_history[2+offset] >> 7) << 2; |
| crc |= (e1i->rx.ts0_history[4+offset] >> 7) << 1; |
| crc |= (e1i->rx.ts0_history[6+offset] >> 7) << 0; |
| |
| return crc; |
| } |
| |
| /* update the current in-progress CRC4 value with data from \a rx_frame */ |
| static void e1_rx_update_crc4(struct osmo_e1f_instance *e1i, const uint8_t *rx_frame) |
| { |
| uint8_t ts0; |
| |
| ts0 = rx_frame[0]; |
| /* mask off the C bits */ |
| if (is_correct_fas(ts0)) |
| ts0 &= 0x7F; |
| e1i->rx.crc4 = crc4itu_update(e1i->rx.crc4, &ts0, 1); |
| /* add the remaining bytes/bits */ |
| e1i->rx.crc4 = crc4itu_update(e1i->rx.crc4, rx_frame+1, ARRAY_SIZE(e1i->ts)-1); |
| } |
| |
| /* FSM State handler */ |
| static void e1_align_search_frame(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv; |
| |
| if (frame_alignment_recovered(e1i)) { |
| /* if we detected the 2nd FAS, we must be in FN 2 (or at least FN%2=0 */ |
| e1i->rx.frame_nr = 2; |
| notify_user(e1i, E1_NTFY_EVT_ALIGN_FRAME, true, NULL); |
| osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_CRC_MFRAME, 0, 0); |
| } |
| } |
| |
| /* FSM State handler */ |
| static void e1_align_search_crc_mframe(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv; |
| |
| if (crc_mframe_alignment_achieved(e1i)) { |
| /* if we detected the 6-bit CRC multiframe signal, we must be in FN 11 */ |
| e1i->rx.frame_nr = 11; |
| /* FIXME: "at least two valid CRC multiframe alignment signals can be located within |
| * 8 ms, the time separating two CRC multiframe alignment signals being 2 ms or a |
| * multiple of 2 ms" */ |
| notify_user(e1i, E1_NTFY_EVT_ALIGN_CRC_MFRAME, true, NULL); |
| osmo_fsm_inst_state_chg(fi, E1_AS_ALIGNED_CRC_MFRAME, 0, 0); |
| } else { |
| /* if no mframe alignment is established within 8ms (64 frames), fall back */ |
| if (e1i->rx.num_ts0_in_mframe_search >= 64) { |
| e1i->rx.num_ts0_in_mframe_search = 0; |
| osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0); |
| } |
| e1i->rx.num_ts0_in_mframe_search++; |
| } |
| } |
| |
| static void e1_aligned_common(struct osmo_e1f_instance *e1i) |
| { |
| uint8_t inb = get_ts0_hist(e1i, 0); |
| |
| /* All non-FAS frames contain "A" bit in TS0 */ |
| if (!is_correct_fas(inb & 0x7F)) { |
| bool old_alarm = e1i->rx.remote_alarm; |
| /* frame not containing the frame alignment signal */ |
| if (inb & 0x20) |
| e1i->rx.remote_alarm = true; |
| else |
| e1i->rx.remote_alarm = false; |
| if (old_alarm != e1i->rx.remote_alarm) |
| notify_user(e1i, E1_NTFY_EVT_REMOTE_ALARM, e1i->rx.remote_alarm, NULL); |
| } |
| } |
| |
| /* FSM State handler */ |
| static void e1_aligned_crc_mframe(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv; |
| |
| if (frame_alignment_lost(e1i)) { |
| osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0); |
| return; |
| } |
| |
| if (e1i->crc4_enabled) { |
| uint8_t crc_rx; |
| bool crc4_error; |
| |
| /* check if we just received a complete CRC4 */ |
| switch (e1i->rx.frame_nr) { |
| case 7: |
| case 15: |
| crc_rx = crc4_from_ts0_hist(e1i, e1i->rx.frame_nr == 15 ? true : false); |
| if (crc_rx != e1i->rx.crc4_last_smf) |
| crc4_error = true; |
| else |
| crc4_error = false; |
| if (crc4_error != e1i->tx.crc4_error) { |
| notify_user(e1i, E1_NTFY_EVT_CRC_ERROR, crc4_error, NULL); |
| e1i->tx.crc4_error = crc4_error; |
| } |
| /* rotate computed CRC4 one further */ |
| e1i->rx.crc4_last_smf = e1i->rx.crc4; |
| e1i->rx.crc4 = crc4itu_init(); |
| break; |
| default: |
| break; |
| } |
| |
| /* check if the remote side reports any CRC errors */ |
| switch (e1i->rx.frame_nr) { |
| case 13: |
| case 15: |
| crc4_error = false; |
| if ((get_ts0_hist(e1i, 0) >> 7) == 0) |
| crc4_error = true; |
| if (crc4_error != e1i->rx.remote_crc4_error) { |
| notify_user(e1i, E1_NTFY_EVT_REMOTE_CRC_ERROR, crc4_error, NULL); |
| e1i->rx.remote_crc4_error = crc4_error; |
| } |
| break; |
| } |
| } |
| |
| e1_aligned_common(e1i); |
| } |
| |
| /* FSM State handler */ |
| static void e1_aligned_basic(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv; |
| |
| if (frame_alignment_lost(e1i)) { |
| osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0); |
| return; |
| } |
| |
| e1_aligned_common(e1i); |
| } |
| |
| static const struct osmo_fsm_state e1_align_states[] = { |
| [E1_AS_SEARCH_FRAME] = { |
| .name = "SEARCH_FRAME", |
| .in_event_mask = S(E1_AE_RX_TS0), |
| .out_state_mask = S(E1_AS_SEARCH_FRAME) | |
| S(E1_AS_SEARCH_CRC_MFRAME) | |
| S(E1_AS_ALIGNED_BASIC), |
| .action = e1_align_search_frame, |
| }, |
| [E1_AS_SEARCH_CRC_MFRAME] = { |
| .name = "SEARCH_CRC_MFRAME", |
| .in_event_mask = S(E1_AE_RX_TS0), |
| .out_state_mask = S(E1_AS_SEARCH_FRAME) | |
| S(E1_AS_SEARCH_CRC_MFRAME) | |
| S(E1_AS_ALIGNED_CRC_MFRAME), |
| .action = e1_align_search_crc_mframe, |
| }, |
| [E1_AS_ALIGNED_CRC_MFRAME] = { |
| .name = "ALIGNED_CRC_MFRAME", |
| .in_event_mask = S(E1_AE_RX_TS0), |
| .out_state_mask = S(E1_AS_SEARCH_FRAME) | |
| S(E1_AS_SEARCH_CRC_MFRAME) | |
| S(E1_AS_ALIGNED_CRC_MFRAME), |
| .action = e1_aligned_crc_mframe, |
| }, |
| [E1_AS_ALIGNED_BASIC] = { |
| .name = "ALIGNED_BASIC", |
| .in_event_mask = S(E1_AE_RX_TS0), |
| .out_state_mask = S(E1_AS_SEARCH_FRAME), |
| .action = e1_aligned_basic, |
| }, |
| }; |
| |
| static void e1_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv; |
| |
| switch (event) { |
| case E1_AE_RESET: |
| e1i->rx.num_ts0_in_mframe_search = 0; |
| osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0); |
| break; |
| } |
| } |
| |
| static struct osmo_fsm e1_align_fsm = { |
| .name = "e1-align", |
| .states = e1_align_states, |
| .num_states = ARRAY_SIZE(e1_align_states), |
| .allstate_event_mask = S(E1_AE_RESET), |
| .allstate_action = e1_allstate, |
| .log_subsys = DLGLOBAL, |
| .event_names = e1_align_evt_names, |
| }; |
| |
| static void align_fsm_reset(struct osmo_e1f_instance *e1i) |
| { |
| osmo_fsm_inst_dispatch(e1i->rx.fi, E1_AE_RESET, NULL); |
| } |
| |
| static void e1_rx_hist_add(struct osmo_e1f_instance *e1i, uint8_t inb) |
| { |
| e1i->rx.ts0_history[e1i->rx.frame_nr] = inb; |
| if (e1i->rx.ts0_hist_len < 16) |
| e1i->rx.ts0_hist_len++; |
| } |
| |
| static void e1_rx_ts0(struct osmo_e1f_instance *e1i, uint8_t inb) |
| { |
| /* append just-received byte to the TS0 receive history buffer */ |
| e1_rx_hist_add(e1i, inb); |
| |
| /* notify the FSM that a new TS0 byte was received */ |
| osmo_fsm_inst_dispatch(e1i->rx.fi, E1_AE_RX_TS0, NULL); |
| |
| e1i->rx.frame_nr = (e1i->rx.frame_nr + 1) % 16; |
| } |
| |
| static void e1_rx_tsN(struct osmo_e1f_instance_ts *e1t, uint8_t inb) |
| { |
| struct msgb *msg; |
| int count, rc; |
| |
| if (!e1t->rx.enabled) |
| return; |
| |
| if (!e1t->rx.msg) |
| e1t->rx.msg = msgb_alloc(e1t->rx.granularity, "E1 Rx"); |
| msg = e1t->rx.msg; |
| OSMO_ASSERT(msg); |
| |
| switch (e1t->mode) { |
| case OSMO_E1F_TS_RAW: |
| /* append byte at end of msgb */ |
| msgb_put_u8(msg, inb); |
| /* flush msgb, if full */ |
| if (msgb_tailroom(msg) <= 0) { |
| goto flush; |
| } |
| break; |
| case OSMO_E1F_TS_HDLC_CRC: |
| rc = osmo_isdnhdlc_decode(&e1t->rx.hdlc, &inb, 1, &count, |
| msgb_data(msg), msgb_tailroom(msg)); |
| switch (rc) { |
| case -OSMO_HDLC_FRAMING_ERROR: |
| fprintf(stdout, "Framing Error\n"); |
| break; |
| case -OSMO_HDLC_CRC_ERROR: |
| fprintf(stdout, "CRC Error\n"); |
| break; |
| case -OSMO_HDLC_LENGTH_ERROR: |
| fprintf(stdout, "Length Error\n"); |
| break; |
| case 0: |
| /* no output yet */ |
| break; |
| default: |
| msgb_put(msg, rc); |
| goto flush; |
| } |
| break; |
| } |
| |
| return; |
| flush: |
| |
| if (!e1t->rx.data_cb) |
| msgb_free(msg); |
| else |
| e1t->rx.data_cb(e1t, msg); |
| e1t->rx.msg = NULL; |
| } |
| |
| /*! Receive a single E1 frame of 32x8 (=256) bits |
| * \param e1i E1 instance for which the frame was received |
| * \param[in] in_frame caller-provided buffer of 32 octets |
| * |
| * The idea is that whoever calls us will already have done the bit-alignment, |
| * i.e. the first bit of TS0 of the frame will be octet-aligned and hence the |
| * entire 256bit buffer is provided as octet-aligned 32bytes in \a in_frame. |
| */ |
| int osmo_e1f_rx_frame(struct osmo_e1f_instance *e1i, const uint8_t *in_frame) |
| { |
| int i; |
| |
| e1_rx_update_crc4(e1i, in_frame); |
| |
| e1_rx_ts0(e1i, in_frame[0]); |
| |
| for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) { |
| struct osmo_e1f_instance_ts *e1t = &e1i->ts[i]; |
| e1_rx_tsN(e1t, in_frame[i]); |
| } |
| |
| return 0; |
| } |
| |
| int osmo_e1f_init(void) |
| { |
| return osmo_fsm_register(&e1_align_fsm); |
| } |