/* tbf_ul_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_ul_ass_fsm_timeouts[32] = { [TBF_UL_ASS_NONE] = {}, [TBF_UL_ASS_SEND_ASS] = { .keep_timer = true }, [TBF_UL_ASS_SEND_ASS_REJ] = {}, [TBF_UL_ASS_WAIT_ACK] = { .keep_timer = true }, }; static const struct value_string tbf_ul_ass_fsm_event_names[] = { { TBF_UL_ASS_EV_SCHED_ASS, "SCHED_ASS" }, { TBF_UL_ASS_EV_SCHED_ASS_REJ, "SCHED_ASS_REJ" }, { TBF_UL_ASS_EV_CREATE_RLCMAC_MSG, "CREATE_RLCMAC_MSG" }, { TBF_UL_ASS_EV_RX_ASS_CTRL_ACK, "RX_ASS_CTRL_ACK" }, { TBF_UL_ASS_EV_ASS_POLL_TIMEOUT, "ASS_POLL_TIMEOUT" }, { TBF_UL_ASS_EV_ABORT, "ABORT" }, { 0, NULL } }; /* Transition to a state, using the T timer defined in tbf_ul_ass_fsm_timeouts. * The actual timeout value is in turn obtained from conn->T_defs. * Assumes local variable fi exists. */ #define tbf_ul_ass_fsm_state_chg(fi, NEXT_STATE) \ osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \ tbf_ul_ass_fsm_timeouts, \ the_pcu->T_defs, \ -1) static struct msgb *create_packet_access_reject(const struct tbf_ul_ass_fsm_ctx *ctx) { struct msgb *msg; struct GprsMs *ms = tbf_ms(ctx->tbf); msg = msgb_alloc(GSM_MACBLOCK_LEN, "rlcmac_ul_ass_rej"); struct bitvec *packet_access_rej = bitvec_alloc(GSM_MACBLOCK_LEN, ctx->tbf); bitvec_unhex(packet_access_rej, DUMMY_VEC); write_packet_access_reject(packet_access_rej, ms_tlli(ms), osmo_tdef_get(ms->bts->pcu->T_defs, 3172, OSMO_TDEF_MS, -1)); bts_do_rate_ctr_inc(ms->bts, CTR_PKT_ACCESS_REJ); bitvec_pack(packet_access_rej, msgb_put(msg, GSM_MACBLOCK_LEN)); bitvec_free(packet_access_rej); return msg; } static struct msgb *create_packet_ul_assign(const struct tbf_ul_ass_fsm_ctx *ctx, const struct tbf_ul_ass_ev_create_rlcmac_msg_ctx *d) { struct msgb *msg = NULL; struct gprs_rlcmac_ul_tbf *new_tbf = NULL; RlcMacDownlink_t *mac_control_block = NULL; struct GprsMs *ms = tbf_ms(ctx->tbf); uint32_t tlli; int rc; unsigned int rrbp; uint32_t new_poll_fn; rc = tbf_check_polling(ctx->tbf, d->pdch, d->fn, &new_poll_fn, &rrbp); if (rc < 0) return NULL; new_tbf = ms_ul_tbf(ms); if (!new_tbf) { LOGPTBF(ctx->tbf, LOGL_ERROR, "We have a schedule for uplink assignment, but there is no uplink TBF\n"); tbf_ul_ass_fsm_state_chg(ctx->fi, TBF_UL_ASS_NONE); return NULL; } msg = msgb_alloc(GSM_MACBLOCK_LEN, "rlcmac_ul_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 != ul_tbf_as_tbf_const(new_tbf)) LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Uplink Assignment (PACCH) for %s\n", tbf_name(ul_tbf_as_tbf_const(new_tbf))); else LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Uplink Assignment (PACCH)\n"); mac_control_block = (RlcMacDownlink_t *)talloc_zero(ctx->tbf, RlcMacDownlink_t); tlli = ms_tlli(ms); write_packet_uplink_assignment(mac_control_block, tbf_tfi(ctx->tbf), (tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF), ms_tlli(ms), tlli != GSM_RESERVED_TMSI, new_tbf, 1, rrbp, bts_get_ms_pwr_alpha(ms->bts), the_pcu->vty.gamma, -1, tbf_is_egprs_enabled(ctx->tbf)); LOGP(DTBF, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++\n"); rc = encode_gsm_rlcmac_downlink(&bv, mac_control_block); if (rc < 0) { LOGP(DTBF, LOGL_ERROR, "Encoding of Packet Uplink Ass failed (%d)\n", rc); goto free_ret; } LOGP(DTBF, LOGL_DEBUG, "------------------------- TX : Packet Uplink Assignment -------------------------\n"); bts_do_rate_ctr_inc(ms->bts, CTR_PKT_UL_ASSIGNMENT); tbf_set_polling(ctx->tbf, d->pdch, new_poll_fn, PDCH_ULC_POLL_UL_ASS); LOGPTBF(ctx->tbf, LOGL_INFO, "Scheduled UL 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) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; unsigned long val; unsigned int sec, micro; if (prev_state == TBF_UL_ASS_SEND_ASS_REJ && tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF) { /* If TBF object doing the UL assignment is also an UL TBF, and * it was just rejected over PACCH, then there's nothing more to do * with this UL TBF other than freeing it and waiting for MS to * retry asking for another UL TBF assignment. But since we are * currently being called from the scheduled (we arrived here * through st_send_ass_rej(TBF_UL_ASS_EV_CREATE_RLCMAC_MSG)), * then we need to delay the tbf_free() to do it asynchrosnouly * in the event loop. Using a fixed 0ms internal fsm timer * number would have been fine here, but since for historical * reasons we have VTY-configurable X2000 for this purpose, keep * using it (it is expected to be 0 usually). */ fi->T = -2000; val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1); sec = val / 1000; micro = (val % 1000) * 1000; LOGPTBF(ctx->tbf, LOGL_DEBUG, "Starting timer X2000 [delay free after Packet Access Reject (PACCH)] with %lums\n", val); osmo_timer_schedule(&fi->timer, sec, micro); } } static void st_none(struct osmo_fsm_inst *fi, uint32_t event, void *data) { switch (event) { case TBF_UL_ASS_EV_SCHED_ASS: tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_SEND_ASS); break; case TBF_UL_ASS_EV_SCHED_ASS_REJ: tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_SEND_ASS_REJ); break; case TBF_UL_ASS_EV_ABORT: /* Nothing to do, we are already in proper state */ break; default: OSMO_ASSERT(0); } } static void st_send_ass_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; unsigned long val; unsigned int sec, micro; struct GprsMs *ms = tbf_ms(ctx->tbf); /* Here it's point in time where we received PKT RES REQ or DL ACK/NACK to request a new UL TBF, * so MS will be gone after T3168 (* 4 retrans, 8.1.1.1.2) if we are unable to seize it. * Hence, attempt re-scheduling PKT UL ASS (states SEND_ASS<->WAIT_ACK ping-pong) until T3168 we * announced (SI13) to the MS expires: */ if (prev_state == TBF_UL_ASS_NONE) { /* tbf_free() called upon trigger */ fi->T = 3168; val = osmo_tdef_get(ms->bts->T_defs_bts, fi->T, OSMO_TDEF_MS, -1); val *= 4; /* 4 PKT RES REQ retransmit */ sec = val / 1000; micro = (val % 1000) * 1000; LOGPTBF(ctx->tbf, LOGL_DEBUG, "Starting timer T3168 [PKT UL ASS PACCH] with %u sec. %u microsec\n", sec, micro); osmo_timer_schedule(&fi->timer, sec, micro); } } static void st_send_ass(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; struct tbf_ul_ass_ev_create_rlcmac_msg_ctx *data_ctx; switch (event) { case TBF_UL_ASS_EV_CREATE_RLCMAC_MSG: data_ctx = (struct tbf_ul_ass_ev_create_rlcmac_msg_ctx *)data; data_ctx->msg = create_packet_ul_assign(ctx, data_ctx); if (!data_ctx->msg) return; tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_WAIT_ACK); break; case TBF_UL_ASS_EV_ABORT: /* Cancel pending schedule for Pkt Ul Ass: */ tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_NONE); break; default: OSMO_ASSERT(0); } } static void st_send_ass_rej(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; struct tbf_ul_ass_ev_create_rlcmac_msg_ctx *data_ctx; switch (event) { case TBF_UL_ASS_EV_CREATE_RLCMAC_MSG: data_ctx = (struct tbf_ul_ass_ev_create_rlcmac_msg_ctx *)data; data_ctx->msg = create_packet_access_reject(ctx); if (!data_ctx->msg) return; tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_NONE); break; case TBF_UL_ASS_EV_ABORT: /* Cancel pending schedule for Pkt Ul Ass Rej: */ tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_NONE); break; default: OSMO_ASSERT(0); } } static void st_wait_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; switch (event) { case TBF_UL_ASS_EV_RX_ASS_CTRL_ACK: tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_NONE); break; case TBF_UL_ASS_EV_ASS_POLL_TIMEOUT: LOGPTBF(ctx->tbf, LOGL_NOTICE, "Timeout for polling PACKET CONTROL ACK for PACKET UPLINK ASSIGNMENT: %s\n", tbf_rlcmac_diag(ctx->tbf)); if (tbf_state(ctx->tbf) == TBF_ST_ASSIGN) { /* Reschedule Pkt Ul Ass */ tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_SEND_ASS); } else { /* We are most probably in RELEASING, so stop retrying. */ tbf_ul_ass_fsm_state_chg(fi, TBF_UL_ASS_NONE); } break; case TBF_UL_ASS_EV_ABORT: /* There's nothing we can do here, we already transmitted and * hence we must keep the POLL since the MS is already expected * to transmit there. Whenever we receive event CTRL_ACK or * TIMEOUT above, it will move back to ST_NONE autoamtically */ break; default: OSMO_ASSERT(0); } } static int tbf_ul_ass_fsm_timer_cb(struct osmo_fsm_inst *fi) { struct tbf_ul_ass_fsm_ctx *ctx = (struct tbf_ul_ass_fsm_ctx *)fi->priv; switch (fi->T) { case -2000: case 3168: tbf_free(ctx->tbf); break; default: OSMO_ASSERT(0); } return 0; } static struct osmo_fsm_state tbf_ul_ass_fsm_states[] = { [TBF_UL_ASS_NONE] = { .in_event_mask = X(TBF_UL_ASS_EV_SCHED_ASS) | X(TBF_UL_ASS_EV_SCHED_ASS_REJ) | X(TBF_UL_ASS_EV_ABORT), .out_state_mask = X(TBF_UL_ASS_SEND_ASS) | X(TBF_UL_ASS_SEND_ASS_REJ), .name = "NONE", .action = st_none, .onenter = st_none_on_enter, }, [TBF_UL_ASS_SEND_ASS] = { .in_event_mask = X(TBF_UL_ASS_EV_CREATE_RLCMAC_MSG) | X(TBF_UL_ASS_EV_ABORT), .out_state_mask = X(TBF_UL_ASS_WAIT_ACK) | X(TBF_UL_ASS_NONE), .name = "SEND_ASS", .action = st_send_ass, .onenter = st_send_ass_on_enter, }, [TBF_UL_ASS_SEND_ASS_REJ] = { .in_event_mask = X(TBF_UL_ASS_EV_CREATE_RLCMAC_MSG) | X(TBF_UL_ASS_EV_ABORT), .out_state_mask = X(TBF_UL_ASS_NONE), .name = "SEND_ASS_REJ", .action = st_send_ass_rej, }, [TBF_UL_ASS_WAIT_ACK] = { .in_event_mask = X(TBF_UL_ASS_EV_RX_ASS_CTRL_ACK) | X(TBF_UL_ASS_EV_ASS_POLL_TIMEOUT) | X(TBF_UL_ASS_EV_ABORT), .out_state_mask = X(TBF_UL_ASS_NONE) | X(TBF_UL_ASS_SEND_ASS), .name = "WAIT_ACK", .action = st_wait_ack, }, }; struct osmo_fsm tbf_ul_ass_fsm = { .name = "UL_ASS_TBF", .states = tbf_ul_ass_fsm_states, .num_states = ARRAY_SIZE(tbf_ul_ass_fsm_states), .timer_cb = tbf_ul_ass_fsm_timer_cb, .log_subsys = DTBF, .event_names = tbf_ul_ass_fsm_event_names, }; static __attribute__((constructor)) void tbf_ul_ass_fsm_init(void) { OSMO_ASSERT(osmo_fsm_register(&tbf_ul_ass_fsm) == 0); } struct msgb *tbf_ul_ass_create_rlcmac_msg(const struct gprs_rlcmac_tbf *tbf, const struct gprs_rlcmac_pdch *pdch, uint32_t fn) { int rc; struct tbf_ul_ass_ev_create_rlcmac_msg_ctx data_ctx = { .pdch = pdch, .fn = fn, .msg = NULL, }; rc = osmo_fsm_inst_dispatch(tbf_ul_ass_fi(tbf), TBF_UL_ASS_EV_CREATE_RLCMAC_MSG, &data_ctx); if (rc != 0 || !data_ctx.msg) return NULL; return data_ctx.msg; } bool tbf_ul_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_ul_ass_fi(tbf); return fi->state == TBF_UL_ASS_SEND_ASS || fi->state == TBF_UL_ASS_SEND_ASS_REJ; }