diff options
Diffstat (limited to 'src/common/handover.c')
| -rw-r--r-- | src/common/handover.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/src/common/handover.c b/src/common/handover.c index c40219db..ab3cbcf8 100644 --- a/src/common/handover.c +++ b/src/common/handover.c @@ -34,6 +34,118 @@ #include <osmo-bts/logging.h> #include <osmo-bts/handover.h> +/* Transmit a handover related PHYS INFO on given lchan */ +static int ho_tx_phys_info(struct gsm_lchan *lchan) +{ + struct msgb *msg = msgb_alloc_headroom(1024, 128, "PHYS INFO"); + struct gsm48_hdr *gh; + + if (!msg) + return -ENOMEM; + + LOGP(DHO, LOGL_INFO, + "%s Sending PHYSICAL INFORMATION to MS.\n", + gsm_lchan_name(lchan)); + + /* Build RSL UNITDATA REQUEST message with 04.08 PHYS INFO */ + msg->l3h = msg->data; + gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh)); + gh->proto_discr = GSM48_PDISC_RR; + gh->msg_type = GSM48_MT_RR_HANDO_INFO; + msgb_put_u8(msg, lchan->rqd_ta); + + rsl_rll_push_l3(msg, RSL_MT_UNIT_DATA_REQ, gsm_lchan2chan_nr(lchan), + 0x00, 0); + + lapdm_rslms_recvmsg(msg, &lchan->lapdm_ch); + return 0; +} + +/* timer call-back for T3105 (handover PHYS INFO re-transmit) */ +static void ho_t3105_cb(void *data) +{ + struct gsm_lchan *lchan = data; + struct gsm_bts *bts = lchan->ts->trx->bts; + struct gsm_bts_role_bts *btsb = bts->role; + + LOGP(DHO, LOGL_INFO, "%s T3105 timeout (%d resends left)\n", + gsm_lchan_name(lchan), btsb->ny1 - lchan->ho.phys_info_count); + + if (lchan->state != LCHAN_S_ACTIVE) { + LOGP(DHO, LOGL_NOTICE, + "%s is in not active. It is in state %s. Ignoring\n", + gsm_lchan_name(lchan), gsm_lchans_name(lchan->state)); + return; + } + + if (lchan->ho.phys_info_count >= btsb->ny1) { + /* HO Abort */ + LOGP(DHO, LOGL_NOTICE, "%s NY1 reached, sending CONNection " + "FAILure to BSC.\n", gsm_lchan_name(lchan)); + rsl_tx_conn_fail(lchan, RSL_ERR_HANDOVER_ACC_FAIL); + return; + } + + ho_tx_phys_info(lchan); + lchan->ho.phys_info_count++; + osmo_timer_schedule(&lchan->ho.t3105, 0, btsb->t3105_ms * 1000); +} + +/* received random access on dedicated channel */ +void handover_rach(struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay) +{ + struct gsm_bts *bts = lchan->ts->trx->bts; + struct gsm_bts_role_bts *btsb = bts->role; + + /* Ignore invalid handover ref */ + if (lchan->ho.ref != ra) { + LOGP(DHO, LOGL_INFO, "%s RACH on dedicated channel received, but " + "ra=0x%02x != expected ref=0x%02x. (This is no bug)\n", + gsm_lchan_name(lchan), ra, lchan->ho.ref); + return; + } + + LOGP(DHO, LOGL_NOTICE, + "%s RACH on dedicated channel received with TA=%u\n", + gsm_lchan_name(lchan), acc_delay); + + /* Set timing advance */ + lchan->rqd_ta = acc_delay; + + /* Stop handover detection, wait for valid frame */ + lchan->ho.active = HANDOVER_WAIT_FRAME; + if (bts_model_rsl_chan_mod(lchan) != 0) { + LOGP(DHO, LOGL_ERROR, + "%s failed to modify channel after handover\n", + gsm_lchan_name(lchan)); + rsl_tx_conn_fail(lchan, RSL_ERR_HANDOVER_ACC_FAIL); + return; + } + + /* Send HANDover DETect to BSC */ + rsl_tx_hando_det(lchan, &lchan->rqd_ta); + + /* Send PHYS INFO */ + lchan->ho.phys_info_count = 1; + ho_tx_phys_info(lchan); + + /* Start T3105 */ + LOGP(DHO, LOGL_DEBUG, + "%s Starting T3105 with %u ms\n", + gsm_lchan_name(lchan), btsb->t3105_ms); + lchan->ho.t3105.cb = ho_t3105_cb; + lchan->ho.t3105.data = lchan; + osmo_timer_schedule(&lchan->ho.t3105, 0, btsb->t3105_ms * 1000); +} + +/* received frist valid data frame on dedicated channel */ +void handover_frame(struct gsm_lchan *lchan) +{ + LOGP(DHO, LOGL_INFO, + "%s First valid frame detected\n", gsm_lchan_name(lchan)); + handover_frame(lchan); +} + /* release handover state */ void handover_reset(struct gsm_lchan *lchan) { |