diff options
Diffstat (limited to 'src/e1gen/osmo_e1f.c')
| -rw-r--r-- | src/e1gen/osmo_e1f.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/src/e1gen/osmo_e1f.c b/src/e1gen/osmo_e1f.c new file mode 100644 index 0000000..2c3fcfb --- /dev/null +++ b/src/e1gen/osmo_e1f.c @@ -0,0 +1,699 @@ +/* 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); +} |