diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 69 | ||||
| -rw-r--r-- | src/gsm/libosmogsm.map | 1 |
2 files changed, 59 insertions, 11 deletions
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index 70eed15e..afff59aa 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -193,6 +193,17 @@ int gsm0808_dec_osmux_cid(uint8_t *cid, const uint8_t *elem, uint8_t len) #endif /* HAVE_SYS_SOCKET_H */ +/* Decode 5-byte LAI list element data (see TS 08.08 3.2.2.27) into MCC/MNC/LAC. */ +static void decode_lai(const uint8_t *data, struct osmo_location_area_id *decoded) +{ + struct gsm48_loc_area_id lai; + + /* Copy data to stack to prevent unaligned access in gsm48_decode_lai2(). */ + memcpy(&lai, data, sizeof(lai)); /* don't byte swap yet */ + + gsm48_decode_lai2(&lai, decoded); +} + /* Helper function for gsm0808_enc_speech_codec() * and gsm0808_enc_speech_codec_list() */ static uint8_t enc_speech_codec(struct msgb *msg, @@ -756,6 +767,53 @@ int gsm0808_dec_encrypt_info(struct gsm0808_encrypt_info *ei, return (int)(elem - old_elem); } +/*! Decode a single GSM 08.08 Cell ID list element payload + * \param[out] out caller-provided output union + * \param[in] discr Cell ID discriminator describing type to be decoded + * \param[in] buf User-provided input buffer containing binary Cell ID list element + * \param[in] len Length of buf + * \returns 0 on success; negative on error */ +int gsm0808_decode_cell_id_u(union gsm0808_cell_id_u *out, enum CELL_IDENT discr, const uint8_t *buf, unsigned int len) +{ + switch (discr) { + case CELL_IDENT_WHOLE_GLOBAL: + if (len < 7) + return -EINVAL; + decode_lai(buf, &out->global.lai); + out->global.cell_identity = osmo_load16be(buf + sizeof(struct gsm48_loc_area_id)); + break; + case CELL_IDENT_LAC_AND_CI: + if (len < 4) + return -EINVAL; + out->lac_and_ci.lac = osmo_load16be(buf); + out->lac_and_ci.ci = osmo_load16be(buf + sizeof(uint16_t)); + break; + case CELL_IDENT_CI: + if (len < 2) + return -EINVAL; + out->ci = osmo_load16be(buf); + break; + case CELL_IDENT_LAI_AND_LAC: + if (len < 5) + return -EINVAL; + decode_lai(buf, &out->lai_and_lac); + break; + case CELL_IDENT_LAC: + if (len < 2) + return -EINVAL; + out->lac = osmo_load16be(buf); + break; + case CELL_IDENT_BSS: + case CELL_IDENT_NO_CELL: + /* Does not have any list items */ + break; + default: + /* Remaining cell identification types are not implemented. */ + return -EINVAL; + } + return 0; +} + void gsm0808_msgb_put_cell_id_u(struct msgb *msg, enum CELL_IDENT id_discr, const union gsm0808_cell_id_u *u) { switch (id_discr) { @@ -865,17 +923,6 @@ uint8_t gsm0808_enc_cell_id_list(struct msgb *msg, return *tlv_len + 2; } -/* Decode 5-byte LAI list element data (see TS 08.08 3.2.2.27) into MCC/MNC/LAC. */ -static void decode_lai(const uint8_t *data, struct osmo_location_area_id *decoded) -{ - struct gsm48_loc_area_id lai; - - /* Copy data to stack to prevent unaligned access in gsm48_decode_lai2(). */ - memcpy(&lai, data, sizeof(lai)); /* don't byte swap yet */ - - gsm48_decode_lai2(&lai, decoded); -} - static int parse_cell_id_global_list(struct gsm0808_cell_id_list2 *cil, const uint8_t *data, size_t remain, size_t *consumed) { diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map index d49401d8..9aa9683a 100644 --- a/src/gsm/libosmogsm.map +++ b/src/gsm/libosmogsm.map @@ -244,6 +244,7 @@ gsm0808_lcls_status_names; gsm0808_enc_lcls; gsm0808_dec_lcls; gsm0808_msgb_put_cell_id_u; +gsm0808_decode_cell_id_u; gsm29118_msgb_alloc; gsm29118_create_alert_req; |