diff options
Diffstat (limited to 'src/tbf_ul_ass_fsm.c')
-rw-r--r-- | src/tbf_ul_ass_fsm.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/src/tbf_ul_ass_fsm.c b/src/tbf_ul_ass_fsm.c new file mode 100644 index 00000000..6f88f112 --- /dev/null +++ b/src/tbf_ul_ass_fsm.c @@ -0,0 +1,392 @@ +/* tbf_ul_ass_fsm.c + * + * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> + * Author: Pau Espin Pedrol <pespin@sysmocom.de> + * + * 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 <unistd.h> + +#include <talloc.h> + +#include <osmocom/core/bitvec.h> + +#include <tbf_ul_ass_fsm.h> +#include <gprs_rlcmac.h> +#include <gprs_debug.h> +#include <gprs_ms.h> +#include <encoding.h> +#include <bts.h> +#include <tbf.h> +#include <tbf_ul.h> + +#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; + + /* Start release after rejecting only if it is UL TBF */ + if (prev_state == TBF_UL_ASS_SEND_ASS_REJ && + tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF) { + /* tbf_free() called upon trigger */ + 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 [reject (PACCH)] with %u sec. %u microsec\n", + sec, micro); + 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; +} |