/* Traffic channel support for NuRAN Wireless Litecell 1.5 BTS L1 */ /* Copyright (C) 2015 by Yves Godin * * Based on sysmoBTS: * (C) 2011-2012 by Harald Welte * * All Rights Reserved * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation; either version 3 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. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "lc15bts.h" #include "l1_if.h" /* input octet-aligned, output not octet-aligned */ void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in, unsigned int num_nibbles) { unsigned int i; unsigned int num_whole_bytes = num_nibbles / 2; /* first byte: upper nibble empty, lower nibble from src */ out[0] = (in[0] >> 4); /* bytes 1.. */ for (i = 1; i < num_whole_bytes; i++) out[i] = ((in[i-1] & 0xF) << 4) | (in[i] >> 4); /* shift the last nibble, in case there's an odd count */ i = num_whole_bytes; if (num_nibbles & 1) out[i] = ((in[i-1] & 0xF) << 4) | (in[i] >> 4); else out[i] = (in[i-1] & 0xF) << 4; } /* input unaligned, output octet-aligned */ void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in, unsigned int num_nibbles) { unsigned int i; unsigned int num_whole_bytes = num_nibbles / 2; for (i = 0; i < num_whole_bytes; i++) out[i] = ((in[i] & 0xF) << 4) | (in[i+1] >> 4); /* shift the last nibble, in case there's an odd count */ i = num_whole_bytes; if (num_nibbles & 1) out[i] = (in[i] & 0xF) << 4; } #define GSM_FR_BITS 260 #define GSM_EFR_BITS 244 #define GSM_FR_BYTES 33 /* TS 101318 Chapter 5.1: 260 bits + 4bit sig */ #define GSM_HR_BYTES 14 /* TS 101318 Chapter 5.2: 112 bits, no sig */ #define GSM_EFR_BYTES 31 /* TS 101318 Chapter 5.3: 244 bits + 4bit sig */ static struct msgb *l1_to_rtppayload_fr(uint8_t *l1_payload, uint8_t payload_len, struct gsm_lchan *lchan) { struct msgb *msg; uint8_t *cur; msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP"); if (!msg) return NULL; /* new L1 can deliver bits like we need them */ cur = msgb_put(msg, GSM_FR_BYTES); memcpy(cur, l1_payload, GSM_FR_BYTES); if (osmo_fr_check_sid(l1_payload, payload_len)) lchan->tch.ul_sid = true; else if (lchan->tch.ul_sid) { lchan->tch.ul_sid = false; lchan->rtp_tx_marker = true; } return msg; } /*! \brief convert GSM-FR from RTP payload to L1 format * \param[out] l1_payload payload part of L1 buffer * \param[in] rtp_payload pointer to RTP payload data * \param[in] payload_len length of \a rtp_payload * \returns number of \a l1_payload bytes filled */ static int rtppayload_to_l1_fr(uint8_t *l1_payload, const uint8_t *rtp_payload, unsigned int payload_len) { /* new L1 can deliver bits like we need them */ memcpy(l1_payload, rtp_payload, GSM_FR_BYTES); return GSM_FR_BYTES; } static struct msgb *l1_to_rtppayload_efr(uint8_t *l1_payload, uint8_t payload_len, struct gsm_lchan *lchan) { struct msgb *msg; uint8_t *cur; msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP"); if (!msg) return NULL; /* new L1 can deliver bits like we need them */ cur = msgb_put(msg, GSM_EFR_BYTES); memcpy(cur, l1_payload, GSM_EFR_BYTES); enum osmo_amr_type ft; enum osmo_amr_quality bfi; uint8_t cmr; int8_t sti, cmi; osmo_amr_rtp_dec(l1_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti); if (ft == AMR_GSM_EFR_SID) lchan->tch.ul_sid = true; else if (lchan->tch.ul_sid) { lchan->tch.ul_sid = false; lchan->rtp_tx_marker = true; } return msg; } static int rtppayload_to_l1_efr(uint8_t *l1_payload, const uint8_t *rtp_payload, unsigned int payload_len) { memcpy(l1_payload, rtp_payload, payload_len); return payload_len; } static struct msgb *l1_to_rtppayload_hr(uint8_t *l1_payload, uint8_t payload_len, struct gsm_lchan *lchan) { struct msgb *msg; uint8_t *cur; msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP"); if (!msg) return NULL; if (payload_len != GSM_HR_BYTES) { LOGP(DL1C, LOGL_ERROR, "L1 HR frame length %u != expected %u\n", payload_len, GSM_HR_BYTES); return NULL; } cur = msgb_put(msg, GSM_HR_BYTES); memcpy(cur, l1_payload, GSM_HR_BYTES); if (osmo_hr_check_sid(l1_payload, payload_len)) lchan->tch.ul_sid = true; else if (lchan->tch.ul_sid) { lchan->tch.ul_sid = false; lchan->rtp_tx_marker = true; } return msg; } /*! \brief convert GSM-FR from RTP payload to L1 format * \param[out] l1_payload payload part of L1 buffer * \param[in] rtp_payload pointer to RTP payload data * \param[in] payload_len length of \a rtp_payload * \returns number of \a l1_payload bytes filled */ static int rtppayload_to_l1_hr(uint8_t *l1_payload, const uint8_t *rtp_payload, unsigned int payload_len) { if (payload_len != GSM_HR_BYTES) { LOGP(DL1C, LOGL_ERROR, "RTP HR frame length %u != expected %u\n", payload_len, GSM_HR_BYTES); return 0; } memcpy(l1_payload, rtp_payload, GSM_HR_BYTES); return GSM_HR_BYTES; } static struct msgb *l1_to_rtppayload_amr(uint8_t *l1_payload, uint8_t payload_len, struct gsm_lchan *lchan) { struct msgb *msg; uint8_t amr_if2_len = payload_len - 2; uint8_t *cur; msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP"); if (!msg) return NULL; cur = msgb_put(msg, amr_if2_len); memcpy(cur, l1_payload+2, amr_if2_len); /* * Audiocode's MGW doesn't like receiving CMRs that are not * the same as the previous one. This means we need to patch * the content here. */ if ((cur[0] & 0xF0) == 0xF0) cur[0]= lchan->tch.last_cmr << 4; else lchan->tch.last_cmr = cur[0] >> 4; return msg; } int get_amr_mode_idx(const struct amr_multirate_conf *amr_mrc, uint8_t cmi) { unsigned int i; for (i = 0; i < amr_mrc->num_modes; i++) { if (amr_mrc->bts_mode[i].mode == cmi) return i; } return -EINVAL; } /*! \brief convert AMR from RTP payload to L1 format * \param[out] l1_payload payload part of L1 buffer * \param[in] rtp_payload pointer to RTP payload data * \param[in] payload_len length of \a rtp_payload * \returns number of \a l1_payload bytes filled */ static int rtppayload_to_l1_amr(uint8_t *l1_payload, const uint8_t *rtp_payload, uint8_t payload_len, struct gsm_lchan *lchan) { struct amr_multirate_conf *amr_mrc = &lchan->tch.amr_mr; enum osmo_amr_type ft; enum osmo_amr_quality bfi; uint8_t cmr; int8_t sti, cmi; uint8_t *l1_cmi_idx = l1_payload; uint8_t *l1_cmr_idx = l1_payload+1; int rc; osmo_amr_rtp_dec(rtp_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti); memcpy(l1_payload+2, rtp_payload, payload_len); /* CMI in downlink tells the L1 encoder which encoding function * it will use, so we have to use the frame type */ switch (ft) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: cmi = ft; LOGP(DRTP, LOGL_DEBUG, "SPEECH frame with CMI %u\n", cmi); break; case AMR_SID: LOGP(DRTP, LOGL_DEBUG, "SID %s frame with CMI %u\n", sti ? "UPDATE" : "FIRST", cmi); break; default: LOGP(DRTP, LOGL_ERROR, "unsupported AMR FT 0x%02x\n", ft); return -EINVAL; break; } rc = get_amr_mode_idx(amr_mrc, cmi); if (rc < 0) { LOGP(DRTP, LOGL_ERROR, "AMR CMI %u not part of AMR MR set\n", cmi); *l1_cmi_idx = 0; } else *l1_cmi_idx = rc; /* Codec Mode Request is in upper 4 bits of RTP payload header, * and we simply copy the CMR into the CMC */ if (cmr == 0xF) { /* FIXME: we need some state about the last codec mode */ *l1_cmr_idx = 0; } else { rc = get_amr_mode_idx(amr_mrc, cmr); if (rc < 0) { /* FIXME: we need some state about the last codec mode */ LOGP(DRTP, LOGL_INFO, "RTP->L1: overriding CMR %u\n", cmr); *l1_cmr_idx = 0; } else *l1_cmr_idx = rc; } #if 0 /* check for bad quality indication */ if (bfi == AMR_GOOD) { /* obtain frame type from AMR FT */ l1_payload[2] = ft; } else { /* bad quality, we should indicate that... */ if (ft == AMR_SID) { /* FIXME: Should we do GsmL1_TchPlType_Amr_SidBad? */ l1_payload[2] = ft; } else { l1_payload[2] = ft; } } #endif if (ft == AMR_SID) { /* store the last SID frame in lchan context */ unsigned int copy_len; copy_len = OSMO_MIN(payload_len+1, ARRAY_SIZE(lchan->tch.last_sid.buf)); lchan->tch.last_sid.len = copy_len; memcpy(lchan->tch.last_sid.buf, l1_payload, copy_len); } return payload_len+1; } #define RTP_MSGB_ALLOC_SIZE 512 /*! \brief function for incoming RTP via TCH.req * \param rs RTP Socket * \param[in] rtp_pl buffer containing RTP payload * \param[in] rtp_pl_len length of \a rtp_pl * * This function prepares a msgb with a L1 PH-DATA.req primitive and * queues it into lchan->dl_tch_queue. * * Note that the actual L1 primitive header is not fully initialized * yet, as things like the frame number, etc. are unknown at the time we * pre-fill the primtive. */ void l1if_tch_encode(struct gsm_lchan *lchan, uint8_t *data, uint8_t *len, const uint8_t *rtp_pl, unsigned int rtp_pl_len) { uint8_t *payload_type; uint8_t *l1_payload; int rc; DEBUGP(DRTP, "%s RTP IN: %s\n", gsm_lchan_name(lchan), osmo_hexdump(rtp_pl, rtp_pl_len)); payload_type = &data[0]; l1_payload = &data[1]; switch (lchan->tch_mode) { case GSM48_CMODE_SPEECH_V1: if (lchan->type == GSM_LCHAN_TCH_F) { *payload_type = GsmL1_TchPlType_Fr; rc = rtppayload_to_l1_fr(l1_payload, rtp_pl, rtp_pl_len); } else{ *payload_type = GsmL1_TchPlType_Hr; rc = rtppayload_to_l1_hr(l1_payload, rtp_pl, rtp_pl_len); } break; case GSM48_CMODE_SPEECH_EFR: *payload_type = GsmL1_TchPlType_Efr; rc = rtppayload_to_l1_efr(l1_payload, rtp_pl, rtp_pl_len); break; case GSM48_CMODE_SPEECH_AMR: *payload_type = GsmL1_TchPlType_Amr; rc = rtppayload_to_l1_amr(l1_payload, rtp_pl, rtp_pl_len, lchan); break; default: /* we don't support CSD modes */ rc = -1; break; } if (rc < 0) { LOGP(DRTP, LOGL_ERROR, "%s unable to parse RTP payload\n", gsm_lchan_name(lchan)); return; } *len = rc + 1; DEBUGP(DRTP, "%s RTP->L1: %s\n", gsm_lchan_name(lchan), osmo_hexdump(data, *len)); } static int is_recv_only(uint8_t speech_mode) { return (speech_mode & 0xF0) == (1 << 4); } /*! \brief receive a traffic L1 primitive for a given lchan */ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg) { GsmL1_Prim_t *l1p = msgb_l1prim(l1p_msg); GsmL1_PhDataInd_t *data_ind = &l1p->u.phDataInd; uint8_t payload_type = data_ind->msgUnitParam.u8Buffer[0]; uint8_t *payload = data_ind->msgUnitParam.u8Buffer + 1; uint8_t payload_len; struct msgb *rmsg = NULL; struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)]; if (is_recv_only(lchan->abis_ip.speech_mode)) return -EAGAIN; if (data_ind->msgUnitParam.u8Size < 1) { LOGP(DL1C, LOGL_ERROR, "chan_nr %d Rx Payload size 0\n", chan_nr); return -EINVAL; } payload_len = data_ind->msgUnitParam.u8Size - 1; switch (payload_type) { case GsmL1_TchPlType_Fr: case GsmL1_TchPlType_Efr: if (lchan->type != GSM_LCHAN_TCH_F) goto err_payload_match; break; case GsmL1_TchPlType_Hr: if (lchan->type != GSM_LCHAN_TCH_H) goto err_payload_match; break; case GsmL1_TchPlType_Amr: if (lchan->type != GSM_LCHAN_TCH_H && lchan->type != GSM_LCHAN_TCH_F) goto err_payload_match; break; case GsmL1_TchPlType_Amr_Onset: if (lchan->type != GSM_LCHAN_TCH_H && lchan->type != GSM_LCHAN_TCH_F) goto err_payload_match; /* according to 3GPP TS 26.093 ONSET frames precede the first speech frame of a speech burst - set the marker for next RTP frame and drop last SID */ lchan->rtp_tx_marker = true; break; default: LOGP(DL1C, LOGL_NOTICE, "%s Rx Payload Type %s is unsupported\n", gsm_lchan_name(lchan), get_value_string(lc15bts_tch_pl_names, payload_type)); break; } switch (payload_type) { case GsmL1_TchPlType_Fr: rmsg = l1_to_rtppayload_fr(payload, payload_len, lchan); break; case GsmL1_TchPlType_Hr: rmsg = l1_to_rtppayload_hr(payload, payload_len, lchan); break; case GsmL1_TchPlType_Efr: rmsg = l1_to_rtppayload_efr(payload, payload_len, lchan); break; case GsmL1_TchPlType_Amr: rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan); break; } if (rmsg) { struct osmo_phsap_prim *l1sap; LOGP(DL1C, LOGL_DEBUG, "%s Rx -> RTP: %s\n", gsm_lchan_name(lchan), osmo_hexdump(rmsg->data, rmsg->len)); /* add l1sap header */ rmsg->l2h = rmsg->data; msgb_push(rmsg, sizeof(*l1sap)); rmsg->l1h = rmsg->data; l1sap = msgb_l1sap_prim(rmsg); osmo_prim_init(&l1sap->oph, SAP_GSM_PH, PRIM_TCH, PRIM_OP_INDICATION, rmsg); l1sap->u.tch.chan_nr = chan_nr; l1sap->u.tch.fn = data_ind->u32Fn; return l1sap_up(trx, l1sap); } return 0; err_payload_match: LOGP(DL1C, LOGL_ERROR, "%s Rx Payload Type %s incompatible with lchan\n", gsm_lchan_name(lchan), get_value_string(lc15bts_tch_pl_names, payload_type)); return -EINVAL; } static inline bool fn_chk(uint8_t *t, uint32_t fn) { uint8_t i; for (i = 0; i < ARRAY_SIZE(t); i++) if (fn % 104 == t[i]) return false; return true; } static bool dtx_sched_optional(struct gsm_lchan *lchan, uint32_t fn) { /* 3GPP TS 45.008 ยง 8.3 */ uint8_t f[] = { 52, 53, 54, 55, 56, 57, 58, 59 }, h0[] = { 0, 2, 4, 6, 52, 54, 56, 58 }, h1[] = { 14, 16, 18, 20, 66, 68, 70, 72 }; if (lchan->tch_mode == GSM48_CMODE_SPEECH_V1) { if (lchan->type == GSM_LCHAN_TCH_F) return fn_chk(f, fn); else return fn_chk(lchan->nr ? h1 : h0, fn); } return false; } static bool repeat_last_sid(struct gsm_lchan *lchan, struct msgb *msg) { GsmL1_Prim_t *l1p; GsmL1_PhDataReq_t *data_req; GsmL1_MsgUnitParam_t *msu_param; uint8_t *l1_payload; l1p = msgb_l1prim(msg); data_req = &l1p->u.phDataReq; msu_param = &data_req->msgUnitParam; l1_payload = &msu_param->u8Buffer[1]; if (lchan->tch.last_sid.len) { memcpy(l1_payload, lchan->tch.last_sid.buf, lchan->tch.last_sid.len); msu_param->u8Size = lchan->tch.last_sid.len + 1; return true; } return false; } /* store the last SID frame in lchan context */ void save_last_sid(struct gsm_lchan *lchan, uint8_t *l1_payload, size_t length, uint32_t fn, bool update) { size_t copy_len = OSMO_MIN(length + 1, ARRAY_SIZE(lchan->tch.last_sid.buf)); lchan->tch.last_sid.len = copy_len; lchan->tch.last_sid.fn = fn; lchan->tch.last_sid.is_update = update; memcpy(lchan->tch.last_sid.buf, l1_payload, copy_len); } struct msgb *gen_empty_tch_msg(struct gsm_lchan *lchan, uint32_t fn) { struct msgb *msg; GsmL1_Prim_t *l1p; GsmL1_PhDataReq_t *data_req; GsmL1_MsgUnitParam_t *msu_param; uint8_t *payload_type; uint8_t *l1_payload; msg = l1p_msgb_alloc(); if (!msg) return NULL; l1p = msgb_l1prim(msg); data_req = &l1p->u.phDataReq; msu_param = &data_req->msgUnitParam; payload_type = &msu_param->u8Buffer[0]; l1_payload = &msu_param->u8Buffer[1]; switch (lchan->tch_mode) { case GSM48_CMODE_SPEECH_AMR: *payload_type = GsmL1_TchPlType_Amr; /* according to 3GPP TS 26.093 A.5.1.1: */ if (lchan->tch.last_sid.is_update) { /* SID UPDATE should be repeated every 8th frame */ if (fn - lchan->tch.last_sid.fn < 7) { msgb_free(msg); return NULL; } } else { /* 3rd frame after SID FIRST should be SID UPDATE */ if (fn - lchan->tch.last_sid.fn < 3) { msgb_free(msg); return NULL; } } if (repeat_last_sid(lchan, msg)) return msg; else { LOGP(DL1C, LOGL_NOTICE, "Have to send AMR frame on TCH " "(FN=%u) but SID buffer is empty - sent NO_DATA\n", fn); osmo_amr_rtp_enc(l1_payload, 0, AMR_NO_DATA, AMR_GOOD); return msg; } break; case GSM48_CMODE_SPEECH_V1: if (lchan->type == GSM_LCHAN_TCH_F) *payload_type = GsmL1_TchPlType_Fr; else *payload_type = GsmL1_TchPlType_Hr; /* unlike AMR, FR & HR schedued based on absolute FN value */ if (dtx_sched_optional(lchan, fn)) { msgb_free(msg); return NULL; } if (repeat_last_sid(lchan, msg)) return msg; else { LOGP(DL1C, LOGL_NOTICE, "Have to send V1 frame on TCH " "(FN=%u) but SID buffer is empty - sent nothing\n", fn); return NULL; } break; case GSM48_CMODE_SPEECH_EFR: *payload_type = GsmL1_TchPlType_Efr; if (dtx_sched_optional(lchan, fn)) { msgb_free(msg); return NULL; } if (repeat_last_sid(lchan, msg)) return msg; else { LOGP(DL1C, LOGL_NOTICE, "Have to send EFR frame on TCH " "(FN=%u) but SID buffer is empty - sent nothing\n", fn); return NULL; } break; default: msgb_free(msg); msg = NULL; break; } return msg; }