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iwd
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band: Add oci_to_frequency 

This adds a utility that can convert an operating class + channel
combination to a frequency.  Operating class is assumed to be a global
operating class from 802.11 Appendix E4.

This information can be found in Operating Channel Information (OCI) IEs,
as well as OWE Transition Mode IEs.
This commit is contained in:
Denis Kenzior 2021-09-15 12:55:55 -05:00
parent 85a6fc25f1
commit ca767aa857
2 changed files with 223 additions and 0 deletions
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221
src/band.c
View File

@ -465,3 +465,224 @@ try_vht80:
return -ENETUNREACH;
}
struct operating_class_info {
uint32_t starting_frequency;
uint32_t flags;
uint8_t channel_set[20];
uint8_t center_frequencies[8];
uint16_t channel_spacing;
uint8_t operating_class;
};
enum operating_class_flags {
PRIMARY_CHANNEL_UPPER = 0x1,
PRIMARY_CHANNEL_LOWER = 0x2,
PLUS80 = 0x4,
};
static const struct operating_class_info e4_operating_classes[] = {
{
.operating_class = 81,
.starting_frequency = 2407,
.channel_set = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 },
.channel_spacing = 20,
},
{
.operating_class = 82,
.starting_frequency = 2414,
.channel_set = { 14 },
.channel_spacing = 20,
},
{
.operating_class = 83,
.starting_frequency = 2407,
.channel_set = { 1, 2, 3, 4, 5, 6, 7, 8, 9 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_LOWER,
},
{
.operating_class = 84,
.starting_frequency = 2407,
.channel_set = { 5, 6, 7, 8, 9, 10, 11, 12, 13 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_UPPER,
},
{
.operating_class = 115,
.starting_frequency = 5000,
.channel_set = { 36, 40, 44, 48},
.channel_spacing = 20,
},
{
.operating_class = 116,
.starting_frequency = 5000,
.channel_set = { 36, 44 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_LOWER,
},
{
.operating_class = 117,
.starting_frequency = 5000,
.channel_set = { 40, 48 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_UPPER,
},
{
.operating_class = 118,
.starting_frequency = 5000,
.channel_set = { 52, 56, 60, 64},
.channel_spacing = 20,
},
{
.operating_class = 119,
.starting_frequency = 5000,
.channel_set = { 52, 60 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_LOWER,
},
{
.operating_class = 120,
.starting_frequency = 5000,
.channel_set = { 56, 64 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_UPPER,
},
{
.operating_class = 121,
.starting_frequency = 5000,
.channel_set = { 100, 104, 108, 112, 116, 120,
124, 128, 132, 136, 140, 144 },
.channel_spacing = 20,
},
{
.operating_class = 122,
.starting_frequency = 5000,
.channel_set = { 100, 108, 116, 124, 132, 140},
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_LOWER,
},
{
.operating_class = 123,
.starting_frequency = 5000,
.channel_set = { 104, 112, 120, 128, 136, 144 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_UPPER,
},
{
.operating_class = 124,
.starting_frequency = 5000,
.channel_set = { 149, 153, 157, 161 },
.channel_spacing = 20,
},
{
.operating_class = 125,
.starting_frequency = 5000,
.channel_set = { 149, 153, 157, 161, 165, 169, 173},
.channel_spacing = 20,
},
{
.operating_class = 126,
.starting_frequency = 5000,
.channel_set = { 149, 157, 165},
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_LOWER,
},
{
.operating_class = 127,
.starting_frequency = 5000,
.channel_set = { 153, 161, 169 },
.channel_spacing = 40,
.flags = PRIMARY_CHANNEL_UPPER,
},
{
.operating_class = 128,
.starting_frequency = 5000,
.channel_spacing = 80,
.center_frequencies = { 42, 58, 106, 122, 138, 155 },
},
{
.operating_class = 129,
.starting_frequency = 5000,
.channel_spacing = 160,
.center_frequencies = { 50, 114 },
},
{
.operating_class = 130,
.starting_frequency = 5000,
.channel_spacing = 80,
.center_frequencies = { 42, 58, 106, 122, 138, 155 },
.flags = PLUS80,
},
};
static const struct operating_class_info *e4_find_opclass(uint32_t opclass)
{
unsigned int i;
for (i = 0; i < L_ARRAY_SIZE(e4_operating_classes); i++) {
if (e4_operating_classes[i].operating_class != opclass)
continue;
return &e4_operating_classes[i];
}
return NULL;
}
static int e4_channel_to_frequency(const struct operating_class_info *info,
uint32_t channel)
{
unsigned int i;
unsigned int offset;
for (i = 0; info->channel_set[i] &&
i < L_ARRAY_SIZE(info->channel_set); i++) {
if (info->channel_set[i] != channel)
continue;
return channel * 5 + info->starting_frequency;
}
/*
* Only classes in Table E4 with center frequencies are 128-130,
* which use 20 Mhz wide channels. Since E4 gives a center frequency,
* calculate the channel offset based on channel spacing.
*
* Typically +/- 6 for 80 Mhz channels and +/- 14 for 160 Mhz channels
*/
offset = (info->channel_spacing - 20) / 5 / 2;
/*
* Check that the channel is in the frequency range given by one of
* the center frequencies listed for the operating class. The channel
* must be a valid channel for a lower operating class and spaced
* 20 mhz apart
*/
for (i = 0; info->center_frequencies[i] &&
i < L_ARRAY_SIZE(info->center_frequencies); i++) {
unsigned int upper = info->center_frequencies[i] + offset;
unsigned int j = info->center_frequencies[i] - offset;
while (j <= upper && channel >= j) {
if (channel == j)
return channel * 5 + info->starting_frequency;
j += 4;
}
}
return -EINVAL;
}
int oci_to_frequency(uint32_t operating_class, uint32_t channel)
{
const struct operating_class_info *info;
info = e4_find_opclass(operating_class);
if (!info)
return -ENOENT;
return e4_channel_to_frequency(info, channel);
}

2
src/band.h
View File

@ -71,3 +71,5 @@ int band_estimate_nonht_rate(const struct band *band,
const uint8_t *supported_rates,
const uint8_t *ext_supported_rates,
int32_t rssi, uint64_t *out_data_rate);
int oci_to_frequency(uint32_t operating_class, uint32_t channel);