diff options
Diffstat (limited to 'src/gsm/gsm0808_utils.c')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index df24e2b8..eef6146d 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -31,6 +31,7 @@ #define IP_V6_ADDR_LEN 16 #define IP_PORT_LEN 2 + /* Encode AoIP transport address element */ uint8_t gsm0808_enc_aoip_trasp_addr(struct msgb *msg, const struct sockaddr_storage *ss) @@ -120,3 +121,188 @@ int gsm0808_dec_aoip_trasp_addr(struct sockaddr_storage *ss, return (int)(elem - old_elem); } + +/* Helper function for gsm0808_enc_speech_codec() + * and gsm0808_enc_speech_codec_list() */ +static uint8_t enc_speech_codec(struct msgb *msg, + const struct gsm0808_speech_codec *sc) +{ + /* See also 3GPP TS 48.008 3.2.2.103 Speech Codec List */ + uint8_t header = 0; + uint8_t *old_tail; + + old_tail = msg->tail; + + if (sc->fi) + header |= (1 << 7); + if (sc->pi) + header |= (1 << 6); + if (sc->pt) + header |= (1 << 5); + if (sc->tf) + header |= (1 << 4); + if (sc->type_extended) { + header |= 0x0f; + msgb_put_u8(msg, header); + } else { + OSMO_ASSERT(sc->type < 0x0f); + header |= sc->type; + msgb_put_u8(msg, header); + return (uint8_t) (msg->tail - old_tail); + } + + msgb_put_u8(msg, sc->type); + + if (sc->cfg_present) + msgb_put_u16(msg, sc->cfg); + + return (uint8_t) (msg->tail - old_tail); +} + +/* Encode Speech Codec element */ +uint8_t gsm0808_enc_speech_codec(struct msgb *msg, + const struct gsm0808_speech_codec *sc) +{ + uint8_t *old_tail; + uint8_t *tlv_len; + + OSMO_ASSERT(msg); + OSMO_ASSERT(sc); + + msgb_put_u8(msg, GSM0808_IE_SPEECH_CODEC); + tlv_len = msgb_put(msg, 1); + old_tail = msg->tail; + + enc_speech_codec(msg, sc); + + *tlv_len = (uint8_t) (msg->tail - old_tail); + return *tlv_len + 2; +} + +/* Decode Speech Codec element */ +int gsm0808_dec_speech_codec(struct gsm0808_speech_codec *sc, + const uint8_t *elem, uint8_t len) +{ + /* See also 3GPP TS 48.008 3.2.2.103 Speech Codec List */ + uint8_t header; + const uint8_t *old_elem = elem; + + OSMO_ASSERT(sc); + if (!elem) + return -EINVAL; + if (len <= 0) + return -EINVAL; + + memset(sc, 0, sizeof(*sc)); + + header = *elem; + + /* Malformed elements */ + if ((header & 0x0F) == 0x0F && len < 2) + return -EINVAL; + else if ((header & 0x0F) != 0x0F && len < 1) + return -EINVAL; + + elem++; + len--; + + if (header & (1 << 7)) + sc->fi = true; + if (header & (1 << 6)) + sc->pi = true; + if (header & (1 << 5)) + sc->pt = true; + if (header & (1 << 4)) + sc->tf = true; + + if ((header & 0x0F) != 0x0F) { + sc->type = (header & 0x0F); + return (int)(elem - old_elem); + } + + sc->type = *elem; + elem++; + len--; + + sc->type_extended = true; + + if (len < 2) + return (int)(elem - old_elem); + + sc->cfg = osmo_load16be(elem); + elem += 2; + sc->cfg_present = true; + + return (int)(elem - old_elem); +} + +/* Encode Speech Codec list */ +uint8_t gsm0808_enc_speech_codec_list(struct msgb *msg, + const struct gsm0808_speech_codec_list *scl) +{ + uint8_t *old_tail; + uint8_t *tlv_len; + unsigned int i; + uint8_t rc; + unsigned int bytes_used = 0; + + OSMO_ASSERT(msg); + OSMO_ASSERT(scl); + + /* Empty list */ + OSMO_ASSERT(scl->len >= 1); + + msgb_put_u8(msg, GSM0808_IE_SPEECH_CODEC_LIST); + tlv_len = msgb_put(msg, 1); + old_tail = msg->tail; + + for (i = 0; i < scl->len; i++) { + rc = enc_speech_codec(msg, &scl->codec[i]); + OSMO_ASSERT(rc >= 1); + bytes_used += rc; + OSMO_ASSERT(bytes_used <= 255); + } + + *tlv_len = (uint8_t) (msg->tail - old_tail); + return *tlv_len + 2; +} + +/* Decode Speech Codec list */ +int gsm0808_dec_speech_codec_list(struct gsm0808_speech_codec_list *scl, + const uint8_t *elem, uint8_t len) +{ + const uint8_t *old_elem = elem; + unsigned int i; + int rc; + uint8_t decoded = 0; + + OSMO_ASSERT(scl); + if (!elem) + return -EINVAL; + if (len <= 0) + return -EINVAL; + + memset(scl, 0, sizeof(*scl)); + + for (i = 0; i < ARRAY_SIZE(scl->codec); i++) { + if (len <= 0) + break; + + rc = gsm0808_dec_speech_codec(&scl->codec[i], elem, len); + if (rc < 1) + return -EINVAL; + + elem+=rc; + len -= rc; + decoded++; + } + + scl->len = decoded; + + /* Empty list */ + if (decoded < 1) { + return -EINVAL; + } + + return (int)(elem - old_elem); +} |