From 03fd8d014f9871896a86534432c8757d65a576fe Mon Sep 17 00:00:00 2001 From: Jonathan Santos Date: Wed, 25 May 2011 13:54:02 -0400 Subject: Import upstream version 0.9.13 --- src/libtrau/trau_frame.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 260 insertions(+) create mode 100644 src/libtrau/trau_frame.c (limited to 'src/libtrau/trau_frame.c') diff --git a/src/libtrau/trau_frame.c b/src/libtrau/trau_frame.c new file mode 100644 index 000000000..d4d6447cc --- /dev/null +++ b/src/libtrau/trau_frame.c @@ -0,0 +1,260 @@ +/* TRAU frame handling according to GSM TS 08.60 */ + +/* (C) 2009 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 Affero 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 + +static u_int32_t get_bits(const u_int8_t *bitbuf, int offset, int num) +{ + int i; + u_int32_t ret = 0; + + for (i = offset; i < offset + num; i++) { + ret = ret << 1; + if (bitbuf[i]) + ret |= 1; + } + return ret; +} + +/* Decode according to 3.1.1 */ +static void decode_fr(struct decoded_trau_frame *fr, const u_int8_t *trau_bits) +{ + int i; + int d_idx = 0; + + /* C1 .. C15 */ + memcpy(fr->c_bits+0, trau_bits+17, 15); + /* C16 .. C21 */ + memcpy(fr->c_bits+15, trau_bits+310, 6); + /* T1 .. T4 */ + memcpy(fr->t_bits+0, trau_bits+316, 4); + /* D1 .. D255 */ + for (i = 32; i < 304; i+= 16) { + memcpy(fr->d_bits + d_idx, trau_bits+i+1, 15); + d_idx += 15; + } + /* D256 .. D260 */ + memcpy(fr->d_bits + d_idx, trau_bits + 305, 5); +} + +/* Decode according to 3.1.2 */ +static void decode_amr(struct decoded_trau_frame *fr, const u_int8_t *trau_bits) +{ + int i; + int d_idx = 0; + + /* C1 .. C15 */ + memcpy(fr->c_bits+0, trau_bits+17, 15); + /* C16 .. C25 */ + memcpy(fr->c_bits+15, trau_bits+33, 10); + /* T1 .. T4 */ + memcpy(fr->t_bits+0, trau_bits+316, 4); + /* D1 .. D5 */ + memcpy(fr->d_bits, trau_bits+43, 5); + /* D6 .. D245 */ + for (i = 48; i < 304; i += 16) { + memcpy(fr->d_bits + d_idx, trau_bits+i+1, 15); + d_idx += 15; + } + /* D246 .. D256 */ + memcpy(fr->d_bits + d_idx, trau_bits + 305, 11); +} + +int decode_trau_frame(struct decoded_trau_frame *fr, const u_int8_t *trau_bits) +{ + u_int8_t cbits5 = get_bits(trau_bits, 17, 5); + + switch (cbits5) { + case TRAU_FT_FR_UP: + case TRAU_FT_FR_DOWN: + case TRAU_FT_IDLE_UP: + case TRAU_FT_IDLE_DOWN: + case TRAU_FT_EFR: + decode_fr(fr, trau_bits); + break; + case TRAU_FT_AMR: + decode_amr(fr, trau_bits); + break; + case TRAU_FT_OM_UP: + case TRAU_FT_OM_DOWN: + case TRAU_FT_DATA_UP: + case TRAU_FT_DATA_DOWN: + case TRAU_FT_D145_SYNC: + case TRAU_FT_EDATA: + LOGP(DMUX, LOGL_NOTICE, "can't decode unimplemented TRAU " + "Frame Type 0x%02x\n", cbits5); + return -1; + break; + default: + LOGP(DMUX, LOGL_NOTICE, "can't decode unknown TRAU " + "Frame Type 0x%02x\n", cbits5); + return -1; + break; + } + + return 0; +} + +const u_int8_t ft_fr_down_bits[] = { 1, 1, 1, 0, 0 }; +const u_int8_t ft_idle_down_bits[] = { 0, 1, 1, 1, 0 }; + +/* modify an uplink TRAU frame so we can send it downlink */ +int trau_frame_up2down(struct decoded_trau_frame *fr) +{ + u_int8_t cbits5 = get_bits(fr->c_bits, 0, 5); + + switch (cbits5) { + case TRAU_FT_FR_UP: + memcpy(fr->c_bits, ft_fr_down_bits, 5); + /* clear time alignment */ + memset(fr->c_bits+5, 0, 6); + /* FIXME: SP / BFI in case of DTx */ + /* C12 .. C21 are spare and coded as '1' */ + memset(fr->c_bits+11, 0x01, 10); + break; + case TRAU_FT_EFR: + /* clear time alignment */ + memset(fr->c_bits+5, 0, 6); + /* FIXME: set UFE appropriately */ + /* FIXME: SP / BFI in case of DTx */ + break; + case TRAU_FT_IDLE_UP: + memcpy(fr->c_bits, ft_idle_down_bits, 5); + /* clear time alignment */ + memset(fr->c_bits+5, 0, 6); + /* FIXME: SP / BFI in case of DTx */ + /* C12 .. C21 are spare and coded as '1' */ + memset(fr->c_bits+11, 0x01, 10); + break; + case TRAU_FT_FR_DOWN: + case TRAU_FT_IDLE_DOWN: + case TRAU_FT_OM_DOWN: + case TRAU_FT_DATA_DOWN: + /* we cannot convert a downlink to a downlink frame */ + return -EINVAL; + break; + case TRAU_FT_AMR: + case TRAU_FT_OM_UP: + case TRAU_FT_DATA_UP: + case TRAU_FT_D145_SYNC: + case TRAU_FT_EDATA: + LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type " + "0x%02x\n", cbits5); + return -1; + break; + default: + LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type " + "0x%02x\n", cbits5); + return -1; + break; + } + + return 0; + +} + +static void encode_fr(u_int8_t *trau_bits, const struct decoded_trau_frame *fr) +{ + int i; + int d_idx = 0; + + trau_bits[16] = 1; + /* C1 .. C15 */ + memcpy(trau_bits+17, fr->c_bits+0, 15); + /* D1 .. D255 */ + for (i = 32; i < 304; i+= 16) { + trau_bits[i] = 1; + memcpy(trau_bits+i+1, fr->d_bits + d_idx, 15); + d_idx += 15; + } + /* D256 .. D260 */ + trau_bits[304] = 1; + memcpy(trau_bits + 305, fr->d_bits + d_idx, 5); + /* C16 .. C21 */ + memcpy(trau_bits+310, fr->c_bits+15, 6); + + /* FIXME: handle timing adjustment */ + + /* T1 .. T4 */ + memcpy(trau_bits+316, fr->t_bits+0, 4); +} + + +int encode_trau_frame(u_int8_t *trau_bits, const struct decoded_trau_frame *fr) +{ + u_int8_t cbits5 = get_bits(fr->c_bits, 0, 5); + + /* 16 bits of sync header */ + memset(trau_bits, 0, 16); + + switch (cbits5) { + case TRAU_FT_FR_UP: + case TRAU_FT_FR_DOWN: + case TRAU_FT_IDLE_UP: + case TRAU_FT_IDLE_DOWN: + case TRAU_FT_EFR: + encode_fr(trau_bits, fr); + break; + case TRAU_FT_AMR: + case TRAU_FT_OM_UP: + case TRAU_FT_OM_DOWN: + case TRAU_FT_DATA_UP: + case TRAU_FT_DATA_DOWN: + case TRAU_FT_D145_SYNC: + case TRAU_FT_EDATA: + LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type " + "0x%02x\n", cbits5); + return -1; + break; + default: + LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type " + "0x%02x\n", cbits5); + return -1; + break; + } + + return 0; +} + +static struct decoded_trau_frame fr_idle_frame = { + .c_bits = { 0, 1, 1, 1, 0 }, /* IDLE DOWNLINK 3.5.5 */ + .t_bits = { 1, 1, 1, 1 }, +}; +static u_int8_t encoded_idle_frame[TRAU_FRAME_BITS]; +static int dbits_initted; + +u_int8_t *trau_idle_frame(void) +{ + /* only initialize during the first call */ + if (!dbits_initted) { + /* set all D-bits to 1 */ + memset(&fr_idle_frame.d_bits, 0x01, 260); + encode_fr(encoded_idle_frame, &fr_idle_frame); + } + return encoded_idle_frame; +} -- cgit v1.2.3