[M] Change in libosmo-abis[master]: rtp2trau: add CSD support

falconia has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmo-abis/+/38133?usp=email ) Change subject: rtp2trau: add CSD support ...................................................................... rtp2trau: add CSD support The previous patch in this series added CSD support to trau2rtp converter; now add the same support in the opposite direction. Change-Id: Ifa1a671f3797a22523bef4b5712d91d0131cdef7 --- M TODO-RELEASE M include/osmocom/trau/trau_rtp.h M src/trau/trau_rtp_conv.c 3 files changed, 222 insertions(+), 0 deletions(-) git pull ssh://gerrit.osmocom.org:29418/libosmo-abis refs/changes/33/38133/1 diff --git a/TODO-RELEASE b/TODO-RELEASE index 0ed7189..6160b28 100644 --- a/TODO-RELEASE +++ b/TODO-RELEASE @@ -7,3 +7,4 @@ # If any interfaces have been added since the last public release: c:r:a + 1. # If any interfaces have been removed or changed since the last public release: c:r:0. #library what description / commit summary line +libosmotrau struct osmo_trau2rtp_state extended (ABI break) diff --git a/include/osmocom/trau/trau_rtp.h b/include/osmocom/trau/trau_rtp.h index 6b2110f..3631b83 100644 --- a/include/osmocom/trau/trau_rtp.h +++ b/include/osmocom/trau/trau_rtp.h @@ -25,6 +25,7 @@ struct osmo_trau2rtp_state { enum osmo_trau_frame_type type; uint8_t rtp_extensions; + bool interm_rate_16k; }; diff --git a/src/trau/trau_rtp_conv.c b/src/trau/trau_rtp_conv.c index 9113f10..06979c6 100644 --- a/src/trau/trau_rtp_conv.c +++ b/src/trau/trau_rtp_conv.c @@ -1055,6 +1055,220 @@ return RFC4040_RTP_PLEN; } +/* + * CSD in the opposite direction: from clearmode RTP input + * to TRAU frame output. + * + * Important note about V.110 frame alignment: in the output from trau2rtp + * process or from OsmoBTS, the 2 or 4 V.110 frames that fit into a 20 ms + * RTP clearmode packet are always perfectly aligned in that packet. + * However, there does not seem to be any formally defined policy in + * Osmocom as to whether this alignment is required in RTP input to + * OsmoBTS or to the future RTP-to-E1 MGW (OsmoMGW extension or otherwise), + * or if these processes are required to hunt for arbitrary V.110 frame + * alignment in their RTP input. + * + * Given that the current CSD implementation in OsmoBTS requires perfect + * V.110 alignment in RTP input, and given that a stateful V.110 alignment + * hunt implementation cannot be fitted into osmo_rtp2trau API, + * the approach implemented here is to also require perfect alignment. + * If our RTP input is not a perfectly aligned pair or quadruple of + * V.110 frames, we emit an idle data frame (all bits set to 1) per + * TS 48.060 section 6.5.1 and TS 48.061 section 6.7.4. + * + * Also note: in the case of OSMO_TRAU16_FT_DATA output, the caller of + * osmo_rtp2trau() API must set st->interm_rate_16k (a Boolean flag) + * appropriately for 8 kbit/s or 16 kbit/s intermediate rate. + * In the absence of out-of-band information, this flag can be set + * from control bit C6 of the first received TRAU-UL frame - that is + * how traditional TRAUs do it. + */ + +static bool check_v110_align(const ubit_t *ra_bits) +{ + int i; + + for (i = 0; i < 8; i++) { + if (ra_bits[i]) + return false; + } + for (i = 1; i < 10; i++) { + if (!ra_bits[i * 8]) + return false; + } + return true; +} + +static void v110_to_63bits(ubit_t *out, const ubit_t *ra_bits) +{ + memcpy(out, ra_bits + 9, 7); + memcpy(out + 7, ra_bits + 17, 7); + memcpy(out + 14, ra_bits + 25, 7); + memcpy(out + 21, ra_bits + 33, 7); + memcpy(out + 28, ra_bits + 41, 7); + memcpy(out + 35, ra_bits + 49, 7); + memcpy(out + 42, ra_bits + 57, 7); + memcpy(out + 49, ra_bits + 65, 7); + memcpy(out + 56, ra_bits + 73, 7); +} + +/* intermediate rate 8 kbit/s */ +static void rtp2trau_data_ir8(struct osmo_trau_frame *tf, const uint8_t *data, + size_t data_len, unsigned second_offset) +{ + ubit_t ra_bits[80 * 2]; + int i; + + if (data_len != RFC4040_RTP_PLEN) + goto idle_fill; + + /* reverse RA2 first */ + for (i = 0; i < sizeof(ra_bits); i++) + ra_bits[i] = (data[i] >> 7) & 1; + + /* enforce two properly aligned V.110 frames */ + if (!check_v110_align(ra_bits)) + goto idle_fill; + if (!check_v110_align(ra_bits + 80)) + goto idle_fill; + + /* all checks passed - copy the payload */ + v110_to_63bits(tf->d_bits, ra_bits); + v110_to_63bits(tf->d_bits + second_offset, ra_bits + 80); + return; + +idle_fill: + memset(tf->d_bits, 1, 63); + memset(tf->d_bits + second_offset, 1, 63); +} + +/* intermediate rate 16 kbit/s */ +static void rtp2trau_data_ir16(struct osmo_trau_frame *tf, const uint8_t *data, + size_t data_len) +{ + ubit_t ra_bits[80 * 4]; + int i, o; + + if (data_len != RFC4040_RTP_PLEN) + goto idle_fill; + + /* reverse RA2 first */ + o = 0; + for (i = 0; i < RFC4040_RTP_PLEN; i++) { + ra_bits[o++] = (data[i] >> 7) & 1; + ra_bits[o++] = (data[i] >> 6) & 1; + } + + /* enforce 4 properly aligned V.110 frames */ + if (!check_v110_align(ra_bits)) + goto idle_fill; + if (!check_v110_align(ra_bits + 80)) + goto idle_fill; + if (!check_v110_align(ra_bits + 80 * 2)) + goto idle_fill; + if (!check_v110_align(ra_bits + 80 * 3)) + goto idle_fill; + + /* all checks passed - copy the payload */ + v110_to_63bits(tf->d_bits, ra_bits); + v110_to_63bits(tf->d_bits + 63, ra_bits + 80); + v110_to_63bits(tf->d_bits + 63 * 2, ra_bits + 80 * 2); + v110_to_63bits(tf->d_bits + 63 * 3, ra_bits + 80 * 3); + return; + +idle_fill: + memset(tf->d_bits, 1, 63 * 4); +} + +static int rtp2trau_data_fr(struct osmo_trau_frame *tf, const uint8_t *data, + size_t data_len, bool interm_rate_16k) +{ + tf->type = OSMO_TRAU16_FT_DATA; + + if (tf->dir == OSMO_TRAU_DIR_UL) { + /* C1 .. C5: FR data UL */ + tf->c_bits[0] = 0; + tf->c_bits[1] = 1; + tf->c_bits[2] = 0; + tf->c_bits[3] = 0; + tf->c_bits[4] = 0; + } else { + /* C1 .. C5: FR data DL */ + tf->c_bits[0] = 1; + tf->c_bits[1] = 0; + tf->c_bits[2] = 1; + tf->c_bits[3] = 1; + tf->c_bits[4] = 0; + } + + if (interm_rate_16k) { + tf->c_bits[5] = 1; + rtp2trau_data_ir16(tf, data, data_len); + } else { + tf->c_bits[5] = 0; + rtp2trau_data_ir8(tf, data, data_len, 63 * 2); + /* remaining data positions are unused in this format */ + memset(tf->d_bits + 63, 1, 63); + memset(tf->d_bits + 63 * 3, 1, 63); + } + + /* remaining C bits are unused */ + memset(tf->c_bits + 6, 1, 9); + + return 0; +} + +static int rtp2trau_data_hr16(struct osmo_trau_frame *tf, const uint8_t *data, + size_t data_len) +{ + tf->type = OSMO_TRAU16_FT_DATA_HR; + + if (tf->dir == OSMO_TRAU_DIR_UL) { + /* C1 .. C5: HR data UL */ + tf->c_bits[0] = 0; + tf->c_bits[1] = 1; + tf->c_bits[2] = 0; + tf->c_bits[3] = 0; + tf->c_bits[4] = 1; + } else { + /* C1 .. C5: HR data DL */ + tf->c_bits[0] = 1; + tf->c_bits[1] = 0; + tf->c_bits[2] = 1; + tf->c_bits[3] = 1; + tf->c_bits[4] = 1; + } + + tf->c_bits[5] = 0; + /* Note that Osmocom trau_frame decoding and encoding API + * puts the second reduced V.110 frame at d_bits position 63, + * unlike 8 kbit/s IR in FR-data frame type where it resides + * at d_bits position 63 * 2. */ + rtp2trau_data_ir8(tf, data, data_len, 63); + + /* remaining C bits are unused */ + memset(tf->c_bits + 6, 1, 9); + + return 0; +} + +static int rtp2trau_data_hr8(struct osmo_trau_frame *tf, const uint8_t *data, + size_t data_len) +{ + tf->type = OSMO_TRAU8_DATA; + + /* C1 .. C5: HR data */ + tf->c_bits[0] = 0; + tf->c_bits[1] = 0; + tf->c_bits[2] = 1; + tf->c_bits[3] = 1; + tf->c_bits[4] = 1; + + rtp2trau_data_ir8(tf, data, data_len, 63); + + return 0; +} + static inline bool check_twts001(struct osmo_trau2rtp_state *st) { if (st->rtp_extensions & OSMO_RTP_EXT_TWTS001) @@ -1104,8 +1318,14 @@ return rtp2trau_efr(tf, rtp, rtp_len); case OSMO_TRAU16_FT_HR: return rtp2trau_hr16(tf, rtp, rtp_len); + case OSMO_TRAU16_FT_DATA: + return rtp2trau_data_fr(tf, rtp, rtp_len, st->interm_rate_16k); + case OSMO_TRAU16_FT_DATA_HR: + return rtp2trau_data_hr16(tf, rtp, rtp_len); case OSMO_TRAU8_SPEECH: return rtp2trau_hr8(tf, rtp, rtp_len); + case OSMO_TRAU8_DATA: + return rtp2trau_data_hr8(tf, rtp, rtp_len); default: return -EINVAL; } -- To view, visit https://gerrit.osmocom.org/c/libosmo-abis/+/38133?usp=email To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings?usp=email Gerrit-MessageType: newchange Gerrit-Project: libosmo-abis Gerrit-Branch: master Gerrit-Change-Id: Ifa1a671f3797a22523bef4b5712d91d0131cdef7 Gerrit-Change-Number: 38133 Gerrit-PatchSet: 1 Gerrit-Owner: falconia &lt;falcon(a)freecalypso.org&gt;