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/* 3GPP TS 48.071 BSSLAP protocol definitions */
/*
* (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Neels Hofmeyr <neels@hofmeyr.de>
*
* SPDX-License-Identifier: GPL-2.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/bsslap.h>
#include <osmocom/gsm/tlv.h>
#include <osmocom/core/logging.h>
/*! \addtogroup bsslap
* @{
* \file bsslap.c
* Message encoding and decoding for 3GPP TS 48.071 BSSLAP protocol.
*/
static const struct tlv_definition osmo_bsslap_tlvdef = {
.def = {
[BSSLAP_IEI_TA] = { TLV_TYPE_TV },
[BSSLAP_IEI_CELL_ID] = { TLV_TYPE_FIXED, 2 },
[BSSLAP_IEI_CHAN_DESC] = { TLV_TYPE_FIXED, 3 },
[BSSLAP_IEI_MEAS_REP] = { TLV_TYPE_TLV },
[BSSLAP_IEI_CAUSE] = { TLV_TYPE_TV },
[BSSLAP_IEI_RRLP_FLAG] = { TLV_TYPE_TV },
[BSSLAP_IEI_RRLP] = { TLV_TYPE_TLV },
[BSSLAP_IEI_CELL_ID_LIST] = { TLV_TYPE_TLV },
[BSSLAP_IEI_ENH_MEAS_REP] = { TLV_TYPE_TLV },
[BSSLAP_IEI_LAC] = { TLV_TYPE_TLV },
[BSSLAP_IEI_FREQ_LIST] = { TLV_TYPE_TLV },
[BSSLAP_IEI_MS_POWER] = { TLV_TYPE_TV },
[BSSLAP_IEI_DELTA_TIMER] = { TLV_TYPE_TV },
[BSSLAP_IEI_SERVING_CELL_ID] = { TLV_TYPE_TLV },
[BSSLAP_IEI_ENCR_KEY] = { TLV_TYPE_FIXED, 8 },
[BSSLAP_IEI_CIPH_MODE_SET] = { TLV_TYPE_TV },
[BSSLAP_IEI_CHAN_MODE] = { TLV_TYPE_TV, 2 },
[BSSLAP_IEI_MR_CONFIG] = { TLV_TYPE_TLV },
[BSSLAP_IEI_POLLING_REPETITION] = { TLV_TYPE_TV },
[BSSLAP_IEI_PACKET_CHAN_DESC] = { TLV_TYPE_FIXED, 4 },
[BSSLAP_IEI_TLLI] = { TLV_TYPE_FIXED, 4 },
[BSSLAP_IEI_TFI] = { TLV_TYPE_TLV },
[BSSLAP_IEI_TBF_START_TIME] = { TLV_TYPE_FIXED, 2 },
[BSSLAP_IEI_PWRUP_START_TIME] = { TLV_TYPE_TLV },
[BSSLAP_IEI_LONG_ENCR_KEY] = { TLV_TYPE_FIXED, 16 },
[BSSLAP_IEI_CONCUR_POS_PROC_F] = { TLV_TYPE_TV },
},
};
#define DEC_ERR(RC, MSG_TYPE, IEI, CAUSE, fmt, args...) do { \
if (err && !*err) { \
*err = talloc_zero(err_ctx, struct osmo_bsslap_err); \
**err = (struct osmo_bsslap_err){ \
.rc = (RC), \
.msg_type = (MSG_TYPE), \
.iei = (IEI), \
.cause = (CAUSE), \
.logmsg = talloc_asprintf(*err, "Error decoding BSSLAP%s%s%s%s%s: " fmt, \
(MSG_TYPE) >= 0 ? " " : "", \
(MSG_TYPE) >= 0 ? osmo_bsslap_msgt_name(MSG_TYPE) : "", \
(IEI) >= 0 ? ": " : "", \
(IEI) >= 0 ? osmo_bsslap_iei_name(IEI) : "", \
(IEI) >= 0 ? " IE" : "", \
##args), \
}; \
} \
return RC; \
} while(0)
static void osmo_bsslap_ie_enc_cell_id(struct msgb *msg, uint16_t cell_id)
{
msgb_put_u8(msg, BSSLAP_IEI_CELL_ID);
msgb_put_u16(msg, cell_id);
}
static int osmo_bsslap_ie_dec_cell_id(uint16_t *cell_id,
enum bsslap_msgt msgt, enum bsslap_iei iei,
struct osmo_bsslap_err **err, void *err_ctx,
const uint8_t *data, size_t len)
{
if (len != 2)
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "Expected 2 bytes, got %zu", len);
*cell_id = osmo_load16be(data);
return 0;
}
static void osmo_bsslap_ie_enc_ta(struct msgb *msg, uint8_t ta)
{
msgb_put_u8(msg, BSSLAP_IEI_TA);
msgb_put_u8(msg, ta);
}
static int osmo_bsslap_ie_dec_ta(uint8_t *ta,
enum bsslap_msgt msgt, enum bsslap_iei iei,
struct osmo_bsslap_err **err, void *err_ctx,
const uint8_t *data, size_t len)
{
if (len != 1)
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "Expected 1 byte, got %zu", len);
*ta = data[0];
return 0;
}
static void osmo_bsslap_ie_enc_cause(struct msgb *msg, enum bsslap_cause cause)
{
msgb_put_u8(msg, BSSLAP_IEI_CAUSE);
msgb_put_u8(msg, cause);
}
static int osmo_bsslap_ie_dec_cause(enum bsslap_cause *cause,
enum bsslap_msgt msgt, enum bsslap_iei iei,
struct osmo_bsslap_err **err, void *err_ctx,
const uint8_t *data, size_t len)
{
if (len != 1)
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "Expected 1 byte, got %zu", len);
*cause = data[0];
return 0;
}
static void osmo_bsslap_ie_enc_chan_desc(struct msgb *msg, const struct gsm48_chan_desc *chan_desc)
{
struct gsm48_chan_desc *put_chan_desc;
msgb_put_u8(msg, BSSLAP_IEI_CHAN_DESC);
put_chan_desc = (void*)msgb_put(msg, sizeof(*chan_desc));
*put_chan_desc = *chan_desc;
}
static int osmo_bsslap_ie_dec_chan_desc(struct gsm48_chan_desc *chan_desc,
enum bsslap_msgt msgt, enum bsslap_iei iei,
struct osmo_bsslap_err **err, void *err_ctx,
const uint8_t *data, size_t len)
{
if (len != sizeof(*chan_desc))
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "Expected %zu bytes, got %zu",
sizeof(*chan_desc), len);
*chan_desc = *(struct gsm48_chan_desc*)data;
return 0;
}
/*! Encode BSSLAP PDU and append to msgb (3GPP TS 48.071).
* \param[out] msg msgb to append to.
* \param[in] pdu PDU data to encode.
* \return number of bytes written, negative on error.
*/
int osmo_bsslap_enc(struct msgb *msg, const struct bsslap_pdu *pdu)
{
uint8_t *old_tail = msg->tail;
msgb_put_u8(msg, pdu->msg_type);
switch (pdu->msg_type) {
case BSSLAP_MSGT_TA_REQUEST:
/* The TA Request message contains only the message type. */
break;
case BSSLAP_MSGT_TA_RESPONSE:
osmo_bsslap_ie_enc_cell_id(msg, pdu->ta_response.cell_id);
osmo_bsslap_ie_enc_ta(msg, pdu->ta_response.ta);
break;
case BSSLAP_MSGT_REJECT:
osmo_bsslap_ie_enc_cause(msg, pdu->reject);
break;
case BSSLAP_MSGT_RESET:
osmo_bsslap_ie_enc_cell_id(msg, pdu->reset.cell_id);
osmo_bsslap_ie_enc_ta(msg, pdu->reset.ta);
osmo_bsslap_ie_enc_chan_desc(msg, &pdu->reset.chan_desc);
osmo_bsslap_ie_enc_cause(msg, pdu->reset.cause);
break;
case BSSLAP_MSGT_ABORT:
osmo_bsslap_ie_enc_cause(msg, pdu->abort);
break;
case BSSLAP_MSGT_TA_LAYER3:
osmo_bsslap_ie_enc_ta(msg, pdu->ta_layer3.ta);
break;
default:
return -ENOTSUP;
}
return (msg->tail - old_tail);
}
/*! Decode BSSLAP PDU (3GPP TS 48.071).
* \param[out] pdu Write decoded values here.
* \param[out] err Returned pointer to error info, dynamically allocated; NULL to not return any.
* \param[in] err_ctx Talloc context to allocate err from, if required.
* \param[in] data Pointer to BSSLAP PDU raw data.
* \param[in] len Data length to decode.
* \return 0 on success, negative on error.
*/
int osmo_bsslap_dec(struct bsslap_pdu *pdu,
struct osmo_bsslap_err **err, void *err_ctx,
const uint8_t *data, size_t len)
{
const uint8_t *ies_start;
int ies_len;
struct tlv_parsed tp;
*pdu = (struct bsslap_pdu){};
if (err)
*err = NULL;
#define DEC_IE_MANDATORY(IEI, DEC_FUN, DEC_FUN_ARG) do { \
const struct tlv_p_entry *e; \
int rc; \
if (!(e = TLVP_GET(&tp, IEI))) \
DEC_ERR(-EINVAL, pdu->msg_type, IEI, LCS_CAUSE_DATA_MISSING_IN_REQ, "missing mandatory IE"); \
rc = DEC_FUN(DEC_FUN_ARG, pdu->msg_type, IEI, err, err_ctx, e->val, e->len); \
if (rc) \
DEC_ERR(rc, pdu->msg_type, IEI, LCS_CAUSE_UNSPECIFIED, "cannot parse IE"); \
} while (0)
if (len < 1)
DEC_ERR(-EINVAL, -1, -1, LCS_CAUSE_UNSPECIFIED, "PDU too short: %zu b", len);
pdu->msg_type = data[0];
if (pdu->msg_type == BSSLAP_MSGT_TA_REQUEST) {
/* The TA Request message contains only the message type. */
return 0;
}
ies_start = &data[1];
ies_len = len - 1;
if (tlv_parse2(&tp, 1, &osmo_bsslap_tlvdef, ies_start, ies_len, 0, 0) <= 0)
DEC_ERR(-EINVAL, pdu->msg_type, -1, LCS_CAUSE_UNSPECIFIED, "failed to parse TLV structure");
switch (pdu->msg_type) {
case BSSLAP_MSGT_TA_RESPONSE:
DEC_IE_MANDATORY(BSSLAP_IEI_CELL_ID, osmo_bsslap_ie_dec_cell_id, &pdu->ta_response.cell_id);
DEC_IE_MANDATORY(BSSLAP_IEI_TA, osmo_bsslap_ie_dec_ta, &pdu->ta_response.ta);
return 0;
case BSSLAP_MSGT_REJECT:
DEC_IE_MANDATORY(BSSLAP_IEI_CAUSE, osmo_bsslap_ie_dec_cause, &pdu->reject);
return 0;
case BSSLAP_MSGT_RESET:
DEC_IE_MANDATORY(BSSLAP_IEI_CELL_ID, osmo_bsslap_ie_dec_cell_id, &pdu->reset.cell_id);
DEC_IE_MANDATORY(BSSLAP_IEI_TA, osmo_bsslap_ie_dec_ta, &pdu->reset.ta);
DEC_IE_MANDATORY(BSSLAP_IEI_CHAN_DESC, osmo_bsslap_ie_dec_chan_desc, &pdu->reset.chan_desc);
DEC_IE_MANDATORY(BSSLAP_IEI_CAUSE, osmo_bsslap_ie_dec_cause, &pdu->reset.cause);
return 0;
case BSSLAP_MSGT_ABORT:
DEC_IE_MANDATORY(BSSLAP_IEI_CAUSE, osmo_bsslap_ie_dec_cause, &pdu->abort);
return 0;
case BSSLAP_MSGT_TA_LAYER3:
DEC_IE_MANDATORY(BSSLAP_IEI_TA, osmo_bsslap_ie_dec_ta, &pdu->ta_layer3.ta);
return 0;
default:
DEC_ERR(-EINVAL, pdu->msg_type, -1, LCS_CAUSE_UNSPECIFIED, "Unsupported message type");
}
}
const struct value_string osmo_bsslap_msgt_names[] = {
{ BSSLAP_MSGT_TA_REQUEST, "TA Request" },
{ BSSLAP_MSGT_TA_RESPONSE, "TA Response" },
{ BSSLAP_MSGT_REJECT, "Reject" },
{ BSSLAP_MSGT_RESET, "Reset" },
{ BSSLAP_MSGT_ABORT, "Abort" },
{ BSSLAP_MSGT_TA_LAYER3, "TA Layer3" },
{ BSSLAP_MSGT_MS_POS_CMD, "MS Position Command" },
{ BSSLAP_MSGT_MS_POS_RESP, "MS Position Response" },
{ BSSLAP_MSGT_UTDOA_REQ, "U-TDOA Request" },
{ BSSLAP_MSGT_UTDOA_RESP, "U-TDOA Response" },
{}
};
const struct value_string osmo_bsslap_iei_names[] = {
{ BSSLAP_IEI_TA, "Timing Advance" },
{ BSSLAP_IEI_CELL_ID, "Cell Identity" },
{ BSSLAP_IEI_CHAN_DESC, "Channel Description" },
{ BSSLAP_IEI_MEAS_REP, "Measurement Report" },
{ BSSLAP_IEI_CAUSE, "Cause" },
{ BSSLAP_IEI_RRLP_FLAG, "RRLP Flag" },
{ BSSLAP_IEI_RRLP, "RRLP" },
{ BSSLAP_IEI_CELL_ID_LIST, "Cell Identity List" },
{ BSSLAP_IEI_ENH_MEAS_REP, "Enhanced Measurement Report" },
{ BSSLAP_IEI_LAC, "Location Area Code" },
{ BSSLAP_IEI_FREQ_LIST, "Frequency List" },
{ BSSLAP_IEI_MS_POWER, "MS Power" },
{ BSSLAP_IEI_DELTA_TIMER, "Delta Timer" },
{ BSSLAP_IEI_SERVING_CELL_ID, "Serving Cell Identifier" },
{ BSSLAP_IEI_ENCR_KEY, "Encryption Key" },
{ BSSLAP_IEI_CIPH_MODE_SET, "Cipher Mode Setting" },
{ BSSLAP_IEI_CHAN_MODE, "Channel Mode" },
{ BSSLAP_IEI_MR_CONFIG, "MultiRate Configuration" },
{ BSSLAP_IEI_POLLING_REPETITION, "Polling Repetition" },
{ BSSLAP_IEI_PACKET_CHAN_DESC, "Packet Channel Description" },
{ BSSLAP_IEI_TLLI, "TLLI" },
{ BSSLAP_IEI_TFI, "TFI" },
{ BSSLAP_IEI_TBF_START_TIME, "TBF Starting Time" },
{ BSSLAP_IEI_PWRUP_START_TIME, "Powerup Starting Time" },
{ BSSLAP_IEI_LONG_ENCR_KEY, "Long Encryption Key" },
{ BSSLAP_IEI_CONCUR_POS_PROC_F, "Concurrent Positioning Flag" },
{}
};
/*! @} */
|
