Spits out the channels as seen on the IE, useful when debugging
issues with APs. When found the equivalent distance of the
coverage class is printed out in meters.
Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
---
Sorry, resending, I mistakenly sent to lkml instead of linux-wireless.
OK so I removed the line that says we're printing IEs and also
added a distance compuation based on Lukáš Turek's forumal.
coverage = (distance + 449) / 450;
coverage/450 = distance + 499
(coverage/450) - 499 = distance
So in meters:
distance = (coverage/450) - 499
scan.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 79 insertions(+), 17 deletions(-)
diff --git a/scan.c b/scan.c
index ec63e61..2d7f15e 100644
--- a/scan.c
+++ b/scan.c
@@ -36,6 +36,23 @@ struct scan_params {
bool show_both_ie_sets;
};
+#define IEEE80211_COUNTRY_EXTENSION_ID 201
+
+struct ieee80211_country_ie_triplet {
+ union {
+ struct {
+ __u8 first_channel;
+ __u8 num_channels;
+ __s8 max_power;
+ } __attribute__ ((packed)) chans;
+ struct {
+ __u8 reg_extension_id;
+ __u8 reg_class;
+ __u8 coverage_class;
+ } __attribute__ ((packed)) ext;
+ };
+} __attribute__ ((packed));
+
static int handle_scan(struct nl80211_state *state,
struct nl_cb *cb,
struct nl_msg *msg,
@@ -143,29 +160,74 @@ static void print_ds(const uint8_t type, uint8_t len, const uint8_t *data)
printf(" channel %d\n", data[0]);
}
-static void print_country(const uint8_t type, uint8_t len, const uint8_t *data)
+static const char *country_env_str(char environment)
{
- int i;
-
- printf(" %.*s", 2, data);
- switch (data[2]) {
+ switch (environment) {
case 'I':
- printf(" (indoor)");
- break;
+ return "Indoor only";
case 'O':
- printf(" (outdoor)");
- break;
+ return "Outdoor only";
case ' ':
- printf(" (in/outdoor)");
- break;
+ return "Indoor/Outdoor";
default:
- printf(" (invalid environment)");
- break;
+ return "bogus";
}
- printf(", data:");
- for(i=0; i<len-3; i++)
- printf(" %.02x", data[i + 3]);
- printf("\n");
+}
+
+/*
+ * Using the inverse of the distance to coverage class
+ * formula we get that in meters
+ * distance = (coverage/450) - 499
+ */
+static int coverage_class_to_distance(__u8 coverage_class)
+{
+ return (coverage_class / 450) - 499;
+}
+
+static void print_country(const uint8_t type, uint8_t len, const uint8_t *data)
+{
+ printf(" %.*s", 2, data);
+
+ printf("\tEnvironment: %s\n", country_env_str(data[2]));
+
+ data += 3;
+ len -= 3;
+
+ if (len < 3) {
+ printf("\t\tNo country IE triplets present\n");
+ return;
+ }
+
+ while (len >= 3) {
+ int end_channel;
+ struct ieee80211_country_ie_triplet *triplet =
+ (struct ieee80211_country_ie_triplet *) data;
+
+ if (triplet->ext.reg_extension_id >= IEEE80211_COUNTRY_EXTENSION_ID) {
+ printf("\t\tExtension ID: %d Regulatory Class: %d Coverage class: %d (Approx %d meters)\n",
+ triplet->ext.reg_extension_id,
+ triplet->ext.reg_class,
+ triplet->ext.coverage_class,
+ coverage_class_to_distance(triplet->ext.coverage_class));
+
+ data += 3;
+ len -= 3;
+ continue;
+ }
+
+ /* 2 GHz */
+ if (triplet->chans.first_channel <= 14)
+ end_channel = triplet->chans.first_channel + (triplet->chans.num_channels - 1);
+ else
+ end_channel = triplet->chans.first_channel + (4 * (triplet->chans.num_channels - 1));
+
+ printf("\t\tChannels [%d - %d]\n", triplet->chans.first_channel, end_channel);
+
+ data += 3;
+ len -= 3;
+ }
+
+ return;
}
static void print_powerconstraint(const uint8_t type, uint8_t len, const uint8_t *data)
--
1.6.3.3
--
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