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gerrit.osmocom.org / osmo-msc / 5d53c6001dc3af457aa32de59ed5fc31d71fcce7 / . / src / libmsc / ran_msg.c
blob: e050303db4807ed5d89cd1aa3b08dd2a7b196a27 [file] [log] [blame]
Neels Hofmeyrc4628a32018-12-07 14:47:34 +0100[diff] [blame]1/* Common bits for RAN message handling */
2/*
3 * (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
4 * All Rights Reserved
5 *
6 * Author: Neels Hofmeyr
7 *
8 * SPDX-License-Identifier: GPL-2.0+
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
Neels Hofmeyrc4628a32018-12-07 14:47:34 +0100[diff] [blame]19 */
20
21#include <osmocom/core/utils.h>
22
23#include <osmocom/msc/ran_msg.h>
24
25const struct value_string ran_msg_type_names[] = {
26 { RAN_MSG_NONE, "NONE" },
27 { RAN_MSG_COMPL_L3, "COMPL_L3" },
28 { RAN_MSG_DTAP, "DTAP" },
29 { RAN_MSG_CLEAR_COMMAND, "CLEAR_COMMAND" },
30 { RAN_MSG_CLEAR_REQUEST, "CLEAR_REQUEST" },
31 { RAN_MSG_CLEAR_COMPLETE, "CLEAR_COMPLETE" },
32 { RAN_MSG_CLASSMARK_REQUEST, "CLASSMARK_REQUEST" },
33 { RAN_MSG_CLASSMARK_UPDATE, "CLASSMARK_UPDATE" },
34 { RAN_MSG_CIPHER_MODE_COMMAND, "CIPHER_MODE_COMMAND" },
35 { RAN_MSG_CIPHER_MODE_COMPLETE, "CIPHER_MODE_COMPLETE" },
36 { RAN_MSG_CIPHER_MODE_REJECT, "CIPHER_MODE_REJECT" },
37 { RAN_MSG_COMMON_ID, "COMMON_ID" },
38 { RAN_MSG_ASSIGNMENT_COMMAND, "ASSIGNMENT_COMMAND" },
39 { RAN_MSG_ASSIGNMENT_COMPLETE, "ASSIGNMENT_COMPLETE" },
40 { RAN_MSG_ASSIGNMENT_FAILURE, "ASSIGNMENT_FAILURE" },
41 { RAN_MSG_SAPI_N_REJECT, "SAPI_N_REJECT" },
42 { RAN_MSG_LCLS_STATUS, "LCLS_STATUS" },
43 { RAN_MSG_LCLS_BREAK_REQ, "LCLS_BREAK_REQ" },
44 { RAN_MSG_HANDOVER_COMMAND, "HANDOVER_COMMAND" },
45 { RAN_MSG_HANDOVER_SUCCEEDED, "HANDOVER_SUCCEEDED" },
46 { RAN_MSG_HANDOVER_PERFORMED, "HANDOVER_PERFORMED" },
47 { RAN_MSG_HANDOVER_REQUIRED, "HANDOVER_REQUIRED" },
48 { RAN_MSG_HANDOVER_REQUIRED_REJECT, "HANDOVER_REQUIRED_REJECT" },
49 { RAN_MSG_HANDOVER_REQUEST, "HANDOVER_REQUEST" },
50 { RAN_MSG_HANDOVER_REQUEST_ACK, "HANDOVER_REQUEST_ACK" },
51 { RAN_MSG_HANDOVER_DETECT, "HANDOVER_DETECT" },
52 { RAN_MSG_HANDOVER_COMPLETE, "HANDOVER_COMPLETE" },
53 { RAN_MSG_HANDOVER_FAILURE, "HANDOVER_FAILURE" },
54 {}
55};
56
57/* extract the N(SD) and return the modulo value for a R99 message */
58static uint8_t ran_dec_dtap_undup_determine_nsd_ret_modulo_r99(uint8_t pdisc, uint8_t msg_type, uint8_t *n_sd)
59{
60 switch (pdisc) {
61 case GSM48_PDISC_MM:
62 case GSM48_PDISC_CC:
63 case GSM48_PDISC_NC_SS:
64 *n_sd = (msg_type >> 6) & 0x3;
65 return 4;
66 case GSM48_PDISC_GROUP_CC:
67 case GSM48_PDISC_BCAST_CC:
68 case GSM48_PDISC_LOC:
69 *n_sd = (msg_type >> 6) & 0x1;
70 return 2;
71 default:
72 /* no sequence number, we cannot detect dups */
73 return 0;
74 }
75}
76
77/* extract the N(SD) and return the modulo value for a R98 message */
78static uint8_t gsm0407_determine_nsd_ret_modulo_r98(uint8_t pdisc, uint8_t msg_type, uint8_t *n_sd)
79{
80 switch (pdisc) {
81 case GSM48_PDISC_MM:
82 case GSM48_PDISC_CC:
83 case GSM48_PDISC_NC_SS:
84 case GSM48_PDISC_GROUP_CC:
85 case GSM48_PDISC_BCAST_CC:
86 case GSM48_PDISC_LOC:
87 *n_sd = (msg_type >> 6) & 0x1;
88 return 2;
89 default:
90 /* no sequence number, we cannot detect dups */
91 return 0;
92 }
93}
94
95/* TS 24.007 11.2.3.2.3 Message Type Octet / Duplicate Detection.
96 * (Not static for unit testing). */
97int ran_dec_dtap_undup_pdisc_ctr_bin(uint8_t pdisc)
98{
99 switch (pdisc) {
100 case GSM48_PDISC_MM:
101 case GSM48_PDISC_CC:
102 case GSM48_PDISC_NC_SS:
103 return 0;
104 case GSM48_PDISC_GROUP_CC:
105 return 1;
106 case GSM48_PDISC_BCAST_CC:
107 return 2;
108 case GSM48_PDISC_LOC:
109 return 3;
110 default:
111 return -1;
112 }
113}
114
115/* TS 24.007 11.2.3.2 Message Type Octet / Duplicate Detection */
116bool ran_dec_dtap_undup_is_duplicate(struct osmo_fsm_inst *log_fi, uint8_t *n_sd_next, bool is_r99, struct msgb *l3)
117{
118 struct gsm48_hdr *gh;
119 uint8_t pdisc;
120 uint8_t n_sd, modulo;
121 int bin;
122
123 gh = msgb_l3(l3);
124 pdisc = gsm48_hdr_pdisc(gh);
125
126 if (is_r99) {
127 modulo = ran_dec_dtap_undup_determine_nsd_ret_modulo_r99(pdisc, gh->msg_type, &n_sd);
128 } else { /* pre R99 */
129 modulo = gsm0407_determine_nsd_ret_modulo_r98(pdisc, gh->msg_type, &n_sd);
130 }
131 if (modulo == 0)
132 return false;
133 bin = ran_dec_dtap_undup_pdisc_ctr_bin(pdisc);
134 if (bin < 0)
135 return false;
136
137 OSMO_ASSERT(bin >= 0 && bin < 4);
138 if (n_sd != n_sd_next[bin]) {
139 /* not what we expected: duplicate */
140 LOGPFSML(log_fi, LOGL_NOTICE, "Duplicate DTAP: bin=%d, expected n_sd == %u, got %u\n",
141 bin, n_sd_next[bin], n_sd);
142 return true;
143 } else {
144 /* as expected: no dup; update expected counter for next message */
145 n_sd_next[bin] = (n_sd + 1) % modulo;
146 return false;
147 }
148}
149
150/* convenience: RAN decode implementations can call this to dispatch the decode_cb with a decoded ran_msg. */
151int ran_decoded(struct ran_dec *ran_dec, struct ran_msg *ran_msg)
152{
153 if (!ran_dec->decode_cb)
154 return -1;
155 return ran_dec->decode_cb(ran_dec->caller_fi, ran_dec->caller_data, ran_msg);
156}