/* tbf_dl_ass_fsm.c * * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH * Author: Pau Espin Pedrol * * 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 #include #include #include #include #include #include #include #include #include #include #define X(s) (1 << (s)) static const struct osmo_tdef_state_timeout tbf_dl_ass_fsm_timeouts[32] = { [TBF_DL_ASS_NONE] = {}, [TBF_DL_ASS_SEND_ASS] = {}, [TBF_DL_ASS_WAIT_ACK] = {}, }; static const struct value_string tbf_dl_ass_fsm_event_names[] = { { TBF_DL_ASS_EV_SCHED_ASS, "SCHED_ASS" }, { TBF_DL_ASS_EV_CREATE_RLCMAC_MSG, "CREATE_RLCMAC_MSG" }, { TBF_DL_ASS_EV_RX_ASS_CTRL_ACK, "RX_ASS_CTRL_ACK" }, { TBF_DL_ASS_EV_ASS_POLL_TIMEOUT, "ASS_POLL_TIMEOUT" }, { TBF_DL_ASS_EV_ABORT, "ABORT" }, { 0, NULL } }; /* Transition to a state, using the T timer defined in tbf_dl_ass_fsm_timeouts. * The actual timeout value is in turn obtained from conn->T_defs. * Assumes local variable fi exists. */ #define tbf_dl_ass_fsm_state_chg(fi, NEXT_STATE) \ osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \ tbf_dl_ass_fsm_timeouts, \ the_pcu->T_defs, \ -1) static struct msgb *create_packet_dl_assign(const struct tbf_dl_ass_fsm_ctx *ctx, const struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *d) { struct msgb *msg; struct gprs_rlcmac_dl_tbf *new_dl_tbf = NULL; RlcMacDownlink_t *mac_control_block = NULL; struct GprsMs *ms = tbf_ms(ctx->tbf); const int poll_ass_dl = 1; unsigned int rrbp = 0; uint32_t new_poll_fn = 0; int rc; bool old_tfi_is_valid = tbf_is_tfi_assigned(ctx->tbf); /* We only use this function in control TS (PACCH) so that MS can always answer the poll */ OSMO_ASSERT(tbf_is_control_ts(ctx->tbf, d->pdch)); rc = tbf_check_polling(ctx->tbf, d->pdch, d->fn, &new_poll_fn, &rrbp); if (rc < 0) return NULL; new_dl_tbf = ms_dl_tbf(ms); if (!new_dl_tbf) { LOGPTBF(ctx->tbf, LOGL_ERROR, "We have a schedule for downlink assignment, but there is no downlink TBF\n"); tbf_dl_ass_fsm_state_chg(ctx->fi, TBF_DL_ASS_NONE); return NULL; } if (old_tfi_is_valid && ms_tlli(ms) == GSM_RESERVED_TMSI) { LOGPTBF(ctx->tbf, LOGL_ERROR, "The old TFI is not assigned and there is no TLLI. New TBF %s\n", tbf_name((struct gprs_rlcmac_tbf *)new_dl_tbf)); tbf_dl_ass_fsm_state_chg(ctx->fi, TBF_DL_ASS_NONE); return NULL; } msg = msgb_alloc(GSM_MACBLOCK_LEN, "rlcmac_dl_ass"); if (!msg) return NULL; /* Initialize a bit vector that uses allocated msgb as the data buffer. */ struct bitvec bv = { .data = msgb_put(msg, GSM_MACBLOCK_LEN), .data_len = GSM_MACBLOCK_LEN, }; bitvec_unhex(&bv, DUMMY_VEC); if (ctx->tbf != (struct gprs_rlcmac_tbf *)new_dl_tbf) LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Downlink Assignment (PACCH) for %s\n", tbf_name((const struct gprs_rlcmac_tbf *)new_dl_tbf)); else LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Downlink Assignment (PACCH)\n"); mac_control_block = (RlcMacDownlink_t *)talloc_zero(ctx->tbf, RlcMacDownlink_t); write_packet_downlink_assignment(mac_control_block, old_tfi_is_valid, tbf_tfi(ctx->tbf), (tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF), new_dl_tbf, poll_ass_dl, rrbp, bts_get_ms_pwr_alpha(ms->bts), the_pcu->vty.gamma, -1, 0, tbf_is_egprs_enabled(ctx->tbf), tbf_state(ctx->tbf) == TBF_ST_WAIT_RELEASE); LOGP(DTBF, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++\n"); rc = encode_gsm_rlcmac_downlink(&bv, mac_control_block); if (rc < 0) { LOGP(DTBF, LOGL_ERROR, "Encoding of Packet Downlink Ass failed (%d)\n", rc); goto free_ret; } LOGP(DTBF, LOGL_DEBUG, "------------------------- TX : Packet Downlink Assignment -------------------------\n"); bts_do_rate_ctr_inc(ms->bts, CTR_PKT_DL_ASSIGNMENT); tbf_set_polling(ctx->tbf, d->pdch, new_poll_fn, PDCH_ULC_POLL_DL_ASS); LOGPTBF(ctx->tbf, LOGL_INFO, "Scheduled DL Assignment polling on PACCH (FN=%d, TS=%d)\n", new_poll_fn, d->pdch->ts_no); talloc_free(mac_control_block); return msg; free_ret: talloc_free(mac_control_block); msgb_free(msg); return NULL; } static void st_none_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { } static void st_none(struct osmo_fsm_inst *fi, uint32_t event, void *data) { switch (event) { case TBF_DL_ASS_EV_SCHED_ASS: tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_SEND_ASS); break; default: OSMO_ASSERT(0); } } static void st_send_ass(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_dl_ass_fsm_ctx *ctx = (struct tbf_dl_ass_fsm_ctx *)fi->priv; struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *data_ctx; switch (event) { case TBF_DL_ASS_EV_CREATE_RLCMAC_MSG: data_ctx = (struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *)data; data_ctx->msg = create_packet_dl_assign(ctx, data_ctx); if (!data_ctx->msg) return; tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_WAIT_ACK); break; case TBF_DL_ASS_EV_ABORT: /* Cancel pending schedule for Pkt Ul Ass: */ tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_NONE); break; default: OSMO_ASSERT(0); } } static void st_wait_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_dl_ass_fsm_ctx *ctx = (struct tbf_dl_ass_fsm_ctx *)fi->priv; switch (event) { case TBF_DL_ASS_EV_RX_ASS_CTRL_ACK: tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_NONE); break; case TBF_DL_ASS_EV_ASS_POLL_TIMEOUT: LOGPTBF(ctx->tbf, LOGL_NOTICE, "Timeout for polling PACKET CONTROL ACK for PACKET DOWNLINK ASSIGNMENT: %s\n", tbf_rlcmac_diag(ctx->tbf)); /* Reschedule Pkt Dl Ass */ tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_SEND_ASS); break; case TBF_DL_ASS_EV_ABORT: tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_NONE); break; default: OSMO_ASSERT(0); } } static int tbf_dl_ass_fsm_timer_cb(struct osmo_fsm_inst *fi) { switch (fi->T) { default: OSMO_ASSERT(0); } return 0; } static struct osmo_fsm_state tbf_dl_ass_fsm_states[] = { [TBF_DL_ASS_NONE] = { .in_event_mask = X(TBF_DL_ASS_EV_SCHED_ASS), .out_state_mask = X(TBF_DL_ASS_SEND_ASS), .name = "NONE", .action = st_none, .onenter = st_none_on_enter, }, [TBF_DL_ASS_SEND_ASS] = { .in_event_mask = X(TBF_DL_ASS_EV_CREATE_RLCMAC_MSG) | X(TBF_DL_ASS_EV_ABORT), .out_state_mask = X(TBF_DL_ASS_WAIT_ACK) | X(TBF_DL_ASS_NONE), .name = "SEND_ASS", .action = st_send_ass, }, [TBF_DL_ASS_WAIT_ACK] = { .in_event_mask = X(TBF_DL_ASS_EV_RX_ASS_CTRL_ACK) | X(TBF_DL_ASS_EV_ASS_POLL_TIMEOUT) | X(TBF_DL_ASS_EV_ABORT), .out_state_mask = X(TBF_DL_ASS_NONE) | X(TBF_DL_ASS_SEND_ASS), .name = "WAIT_ACK", .action = st_wait_ack, }, }; struct osmo_fsm tbf_dl_ass_fsm = { .name = "DL_ASS_TBF", .states = tbf_dl_ass_fsm_states, .num_states = ARRAY_SIZE(tbf_dl_ass_fsm_states), .timer_cb = tbf_dl_ass_fsm_timer_cb, .log_subsys = DTBF, .event_names = tbf_dl_ass_fsm_event_names, }; static __attribute__((constructor)) void tbf_dl_ass_fsm_init(void) { OSMO_ASSERT(osmo_fsm_register(&tbf_dl_ass_fsm) == 0); } struct msgb *tbf_dl_ass_create_rlcmac_msg(const struct gprs_rlcmac_tbf *tbf, const struct gprs_rlcmac_pdch *pdch, uint32_t fn) { int rc; struct tbf_dl_ass_ev_create_rlcmac_msg_ctx data_ctx = { .pdch = pdch, .fn = fn, .msg = NULL, }; rc = osmo_fsm_inst_dispatch(tbf_dl_ass_fi(tbf), TBF_DL_ASS_EV_CREATE_RLCMAC_MSG, &data_ctx); if (rc != 0 || !data_ctx.msg) return NULL; return data_ctx.msg; } bool tbf_dl_ass_rts(const struct gprs_rlcmac_tbf *tbf, const struct gprs_rlcmac_pdch *pdch) { struct osmo_fsm_inst *fi; if (!tbf_is_control_ts(tbf, pdch)) return false; fi = tbf_dl_ass_fi(tbf); if (fi->state != TBF_DL_ASS_SEND_ASS) return false; if (tbf_ul_ass_fi(tbf)->state == TBF_UL_ASS_WAIT_ACK) { LOGPTBF(tbf, LOGL_DEBUG, "Polling is already scheduled, so we must wait for the uplink assignment...\n"); return false; } /* on uplink TBF we get the downlink TBF to be assigned. */ if (tbf_direction(tbf) == GPRS_RLCMAC_UL_TBF) { const struct gprs_rlcmac_ul_tbf *ul_tbf = (const struct gprs_rlcmac_ul_tbf *)tbf; /* be sure to check first, if contention resolution is done, * otherwise we cannot send the assignment yet (3GPP TS 44.060 sec 7.1.3.1) */ if (!ul_tbf_contention_resolution_done(ul_tbf)) { LOGPTBF(tbf, LOGL_DEBUG, "Cannot assign DL TBF now, because contention resolution is not finished.\n"); return false; } } return true; }