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Diffstat (limited to 'src/libmsc/ran_msg.c')
| -rw-r--r-- | src/libmsc/ran_msg.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/src/libmsc/ran_msg.c b/src/libmsc/ran_msg.c new file mode 100644 index 000000000..46816a961 --- /dev/null +++ b/src/libmsc/ran_msg.c @@ -0,0 +1,160 @@ +/* Common bits for RAN message handling */ +/* + * (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de> + * All Rights Reserved + * + * Author: Neels Hofmeyr + * + * 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 <osmocom/core/utils.h> + +#include <osmocom/msc/ran_msg.h> + +const struct value_string ran_msg_type_names[] = { + { RAN_MSG_NONE, "NONE" }, + { RAN_MSG_COMPL_L3, "COMPL_L3" }, + { RAN_MSG_DTAP, "DTAP" }, + { RAN_MSG_CLEAR_COMMAND, "CLEAR_COMMAND" }, + { RAN_MSG_CLEAR_REQUEST, "CLEAR_REQUEST" }, + { RAN_MSG_CLEAR_COMPLETE, "CLEAR_COMPLETE" }, + { RAN_MSG_CLASSMARK_REQUEST, "CLASSMARK_REQUEST" }, + { RAN_MSG_CLASSMARK_UPDATE, "CLASSMARK_UPDATE" }, + { RAN_MSG_CIPHER_MODE_COMMAND, "CIPHER_MODE_COMMAND" }, + { RAN_MSG_CIPHER_MODE_COMPLETE, "CIPHER_MODE_COMPLETE" }, + { RAN_MSG_CIPHER_MODE_REJECT, "CIPHER_MODE_REJECT" }, + { RAN_MSG_COMMON_ID, "COMMON_ID" }, + { RAN_MSG_ASSIGNMENT_COMMAND, "ASSIGNMENT_COMMAND" }, + { RAN_MSG_ASSIGNMENT_COMPLETE, "ASSIGNMENT_COMPLETE" }, + { RAN_MSG_ASSIGNMENT_FAILURE, "ASSIGNMENT_FAILURE" }, + { RAN_MSG_SAPI_N_REJECT, "SAPI_N_REJECT" }, + { RAN_MSG_LCLS_STATUS, "LCLS_STATUS" }, + { RAN_MSG_LCLS_BREAK_REQ, "LCLS_BREAK_REQ" }, + { RAN_MSG_HANDOVER_COMMAND, "HANDOVER_COMMAND" }, + { RAN_MSG_HANDOVER_SUCCEEDED, "HANDOVER_SUCCEEDED" }, + { RAN_MSG_HANDOVER_PERFORMED, "HANDOVER_PERFORMED" }, + { RAN_MSG_HANDOVER_REQUIRED, "HANDOVER_REQUIRED" }, + { RAN_MSG_HANDOVER_REQUIRED_REJECT, "HANDOVER_REQUIRED_REJECT" }, + { RAN_MSG_HANDOVER_REQUEST, "HANDOVER_REQUEST" }, + { RAN_MSG_HANDOVER_REQUEST_ACK, "HANDOVER_REQUEST_ACK" }, + { RAN_MSG_HANDOVER_DETECT, "HANDOVER_DETECT" }, + { RAN_MSG_HANDOVER_COMPLETE, "HANDOVER_COMPLETE" }, + { RAN_MSG_HANDOVER_FAILURE, "HANDOVER_FAILURE" }, + {} +}; + +/* extract the N(SD) and return the modulo value for a R99 message */ +static uint8_t ran_dec_dtap_undup_determine_nsd_ret_modulo_r99(uint8_t pdisc, uint8_t msg_type, uint8_t *n_sd) +{ + switch (pdisc) { + case GSM48_PDISC_MM: + case GSM48_PDISC_CC: + case GSM48_PDISC_NC_SS: + *n_sd = (msg_type >> 6) & 0x3; + return 4; + case GSM48_PDISC_GROUP_CC: + case GSM48_PDISC_BCAST_CC: + case GSM48_PDISC_LOC: + *n_sd = (msg_type >> 6) & 0x1; + return 2; + default: + /* no sequence number, we cannot detect dups */ + return 0; + } +} + +/* extract the N(SD) and return the modulo value for a R98 message */ +static uint8_t gsm0407_determine_nsd_ret_modulo_r98(uint8_t pdisc, uint8_t msg_type, uint8_t *n_sd) +{ + switch (pdisc) { + case GSM48_PDISC_MM: + case GSM48_PDISC_CC: + case GSM48_PDISC_NC_SS: + case GSM48_PDISC_GROUP_CC: + case GSM48_PDISC_BCAST_CC: + case GSM48_PDISC_LOC: + *n_sd = (msg_type >> 6) & 0x1; + return 2; + default: + /* no sequence number, we cannot detect dups */ + return 0; + } +} + +/* TS 24.007 11.2.3.2.3 Message Type Octet / Duplicate Detection. + * (Not static for unit testing). */ +int ran_dec_dtap_undup_pdisc_ctr_bin(uint8_t pdisc) +{ + switch (pdisc) { + case GSM48_PDISC_MM: + case GSM48_PDISC_CC: + case GSM48_PDISC_NC_SS: + return 0; + case GSM48_PDISC_GROUP_CC: + return 1; + case GSM48_PDISC_BCAST_CC: + return 2; + case GSM48_PDISC_LOC: + return 3; + default: + return -1; + } +} + +/* TS 24.007 11.2.3.2 Message Type Octet / Duplicate Detection */ +bool ran_dec_dtap_undup_is_duplicate(struct osmo_fsm_inst *log_fi, uint8_t *n_sd_next, bool is_r99, struct msgb *l3) +{ + struct gsm48_hdr *gh; + uint8_t pdisc; + uint8_t n_sd, modulo; + int bin; + + gh = msgb_l3(l3); + pdisc = gsm48_hdr_pdisc(gh); + + if (is_r99) { + modulo = ran_dec_dtap_undup_determine_nsd_ret_modulo_r99(pdisc, gh->msg_type, &n_sd); + } else { /* pre R99 */ + modulo = gsm0407_determine_nsd_ret_modulo_r98(pdisc, gh->msg_type, &n_sd); + } + if (modulo == 0) + return false; + bin = ran_dec_dtap_undup_pdisc_ctr_bin(pdisc); + if (bin < 0) + return false; + + OSMO_ASSERT(bin >= 0 && bin < 4); + if (n_sd != n_sd_next[bin]) { + /* not what we expected: duplicate */ + LOGPFSML(log_fi, LOGL_NOTICE, "Duplicate DTAP: bin=%d, expected n_sd == %u, got %u\n", + bin, n_sd_next[bin], n_sd); + return true; + } else { + /* as expected: no dup; update expected counter for next message */ + n_sd_next[bin] = (n_sd + 1) % modulo; + return false; + } +} + +/* convenience: RAN decode implementations can call this to dispatch the decode_cb with a decoded ran_msg. */ +int ran_decoded(struct ran_dec *ran_dec, struct ran_msg *ran_msg) +{ + if (!ran_dec->decode_cb) + return -1; + return ran_dec->decode_cb(ran_dec->caller_fi, ran_dec->caller_data, ran_msg); +} |