1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
#include <stdint.h>
#include <errno.h>
#include <osmocom/core/logging.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/amr.h>
void amr_log_mr_conf(int ss, int logl, const char *pfx,
struct amr_multirate_conf *amr_mrc)
{
int i;
LOGP(ss, logl, "%s AMR MR Conf: num_modes=%u",
pfx, amr_mrc->num_modes);
for (i = 0; i < amr_mrc->num_modes; i++)
LOGPC(ss, logl, ", mode[%u] = %u/%u/%u",
i, amr_mrc->bts_mode[i].mode,
amr_mrc->bts_mode[i].threshold,
amr_mrc->bts_mode[i].hysteresis);
LOGPC(ss, logl, "\n");
}
static inline int get_amr_mode_idx(const struct amr_multirate_conf *amr_mrc,
uint8_t cmi)
{
unsigned int i;
for (i = 0; i < amr_mrc->num_modes; i++) {
if (amr_mrc->bts_mode[i].mode == cmi)
return i;
}
return -EINVAL;
}
static inline uint8_t set_cmr_mode_idx(const struct amr_multirate_conf *amr_mrc,
uint8_t cmr)
{
int rc;
/* Codec Mode Request is in upper 4 bits of RTP payload header,
* and we simply copy the CMR into the CMC */
if (cmr == 0xF) {
/* FIXME: we need some state about the last codec mode */
return 0;
}
rc = get_amr_mode_idx(amr_mrc, cmr);
if (rc < 0) {
/* FIXME: we need some state about the last codec mode */
LOGP(DRTP, LOGL_INFO, "RTP->L1: overriding CMR %u\n", cmr);
return 0;
}
return rc;
}
static inline uint8_t set_cmi_mode_idx(const struct amr_multirate_conf *amr_mrc,
uint8_t cmi)
{
int rc = get_amr_mode_idx(amr_mrc, cmi);
if (rc < 0) {
LOGP(DRTP, LOGL_ERROR, "AMR CMI %u not part of AMR MR set\n",
cmi);
return 0;
}
return rc;
}
void amr_set_mode_pref(uint8_t *data, const struct amr_multirate_conf *amr_mrc,
uint8_t cmi, uint8_t cmr)
{
data[0] = set_cmi_mode_idx(amr_mrc, cmi);
data[1] = set_cmr_mode_idx(amr_mrc, cmr);
}
/* parse a GSM 04.08 MultiRate Config IE (10.5.2.21aa) in a more
* comfortable internal data structure */
int amr_parse_mr_conf(struct amr_multirate_conf *amr_mrc,
const uint8_t *mr_conf, unsigned int len)
{
uint8_t mr_version = mr_conf[0] >> 5;
uint8_t num_codecs = 0;
int i, j = 0;
if (mr_version != 1) {
LOGP(DRSL, LOGL_ERROR, "AMR Multirate Version %u unknonw\n",
mr_version);
goto ret_einval;
}
/* check number of active codecs */
for (i = 0; i < 8; i++) {
if (mr_conf[1] & (1 << i))
num_codecs++;
}
/* check for minimum length */
if (num_codecs == 0 ||
(num_codecs == 1 && len < 2) ||
(num_codecs == 2 && len < 4) ||
(num_codecs == 3 && len < 5) ||
(num_codecs == 4 && len < 6) ||
(num_codecs > 4)) {
LOGP(DRSL, LOGL_ERROR, "AMR Multirate with %u modes len=%u "
"not possible\n", num_codecs, len);
goto ret_einval;
}
/* copy the first two octets of the IE */
amr_mrc->gsm48_ie[0] = mr_conf[0];
amr_mrc->gsm48_ie[1] = mr_conf[1];
amr_mrc->num_modes = num_codecs;
for (i = 0; i < 8; i++) {
if (mr_conf[1] & (1 << i)) {
amr_mrc->bts_mode[j++].mode = i;
}
}
if (num_codecs >= 2) {
amr_mrc->bts_mode[0].threshold = mr_conf[1] & 0x3F;
amr_mrc->bts_mode[0].hysteresis = mr_conf[2] >> 4;
}
if (num_codecs >= 3) {
amr_mrc->bts_mode[1].threshold =
((mr_conf[2] & 0xF) << 2) | (mr_conf[3] >> 6);
amr_mrc->bts_mode[1].hysteresis = (mr_conf[3] >> 2) & 0xF;
}
if (num_codecs >= 4) {
amr_mrc->bts_mode[2].threshold =
((mr_conf[3] & 0x3) << 4) | (mr_conf[4] >> 4);
amr_mrc->bts_mode[2].hysteresis = mr_conf[4] & 0xF;
}
return num_codecs;
ret_einval:
return -EINVAL;
}
/*! \brief determine AMR initial codec mode for given logical channel
* \returns integer between 0..3 for AMR codce mode 1..4 */
unsigned int amr_get_initial_mode(struct gsm_lchan *lchan)
{
struct amr_multirate_conf *amr_mrc = &lchan->tch.amr_mr;
struct gsm48_multi_rate_conf *mr_conf =
(struct gsm48_multi_rate_conf *) amr_mrc->gsm48_ie;
if (mr_conf->icmi) {
/* initial mode given, coding in TS 05.09 3.4.1 */
return mr_conf->smod;
} else {
/* implicit rule according to TS 05.09 Chapter 3.4.3 */
switch (amr_mrc->num_modes) {
case 2:
case 3:
/* return the most robust */
return 0;
case 4:
/* return the second-most robust */
return 1;
case 1:
default:
/* return the only mode we have */
return 0;
}
}
}
|
