[PATCH] iw: add beacon hint event parsing

Here's a screenshot:

mcgrof@pogo ~ $ iw event

mcgrof@pogo ~ $ sudo iw dev wlan0 scan trigger

phy #0: beacon hint:
phy0 5180 MHz [36]:
        o active scanning enabled
        o beaconing enabled

You'll see this on every channel you find a beacon and a flag
is lifted.

Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
---

This patch was sitting in a cave lonely since March 31st, seems we forgot
about it it, poor patch. I rebased it.

 event.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 69 insertions(+), 0 deletions(-)

diff --git a/event.c b/event.c
index 2671331..0cd3c75 100644
--- a/event.c
+++ b/event.c
@@ -9,6 +9,38 @@ static int no_seq_check(struct nl_msg *msg, void *arg)
        return NL_OK;
 }
 
+struct ieee80211_beacon_channel {
+       __u16 center_freq;
+       bool passive_scan;
+       bool no_ibss;
+};
+
+static int parse_beacon_hint_chan(struct nlattr *tb,
+                                 struct ieee80211_beacon_channel *chan)
+{
+       struct nlattr *tb_freq[NL80211_FREQUENCY_ATTR_MAX + 1];
+       static struct nla_policy beacon_freq_policy[NL80211_FREQUENCY_ATTR_MAX 
+ 1] = {
+               [NL80211_FREQUENCY_ATTR_FREQ] = { .type = NLA_U32 },
+               [NL80211_FREQUENCY_ATTR_PASSIVE_SCAN] = { .type = NLA_FLAG },
+               [NL80211_FREQUENCY_ATTR_NO_IBSS] = { .type = NLA_FLAG },
+       };
+
+       if (nla_parse_nested(tb_freq,
+                            NL80211_FREQUENCY_ATTR_MAX,
+                            tb,
+                            beacon_freq_policy))
+               return -EINVAL;
+
+       chan->center_freq = nla_get_u32(tb_freq[NL80211_FREQUENCY_ATTR_FREQ]);
+
+       if (tb_freq[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN])
+               chan->passive_scan = true;
+       if (tb_freq[NL80211_FREQUENCY_ATTR_NO_IBSS])
+               chan->no_ibss = true;
+
+       return 0;
+}
+
 static void print_frame(struct print_event_args *args, struct nlattr *attr)
 {
        uint8_t *frame;
@@ -70,12 +102,21 @@ static void print_frame(struct print_event_args *args, 
struct nlattr *attr)
 
 static int print_event(struct nl_msg *msg, void *arg)
 {
+#define PARSE_BEACON_CHAN(_attr, _chan) do { \
+       r = parse_beacon_hint_chan(tb[_attr], \
+                                  &_chan); \
+       if (r) \
+               return NL_SKIP; \
+} while (0)
        struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
        struct nlattr *tb[NL80211_ATTR_MAX + 1], *nst;
        struct print_event_args *args = arg;
        char ifname[100];
        char macbuf[6*3];
        __u8 reg_type;
+       struct ieee80211_beacon_channel chan_before_beacon,  chan_after_beacon;
+       __u32 wiphy_idx = 0;
+       int r;
        int rem_nst;
        __u16 status;
 
@@ -159,6 +200,33 @@ static int print_event(struct nl_msg *msg, void *arg)
 
                printf("\n");
                break;
+       case NL80211_CMD_REG_BEACON_HINT:
+
+               wiphy_idx = nla_get_u32(tb[NL80211_ATTR_WIPHY]);
+
+               memset(&chan_before_beacon, 0, sizeof(chan_before_beacon));
+               memset(&chan_after_beacon, 0, sizeof(chan_after_beacon));
+
+               PARSE_BEACON_CHAN(NL80211_ATTR_FREQ_BEFORE, chan_before_beacon);
+               PARSE_BEACON_CHAN(NL80211_ATTR_FREQ_AFTER, chan_after_beacon);
+
+               if (chan_before_beacon.center_freq != 
chan_after_beacon.center_freq)
+                       break;
+
+               /* A beacon hint is sent _only_ if something _did_ change */
+               printf("beacon hint:\n");
+
+               printf("phy%d %d MHz [%d]:\n",
+                      wiphy_idx,
+                      chan_before_beacon.center_freq,
+                      
ieee80211_frequency_to_channel(chan_before_beacon.center_freq));
+
+               if (chan_before_beacon.passive_scan && 
!chan_after_beacon.passive_scan)
+                       printf("\to active scanning enabled\n");
+               if (chan_before_beacon.no_ibss && !chan_after_beacon.no_ibss)
+                       printf("\to beaconing enabled\n");
+
+               break;
        case NL80211_CMD_JOIN_IBSS:
                mac_addr_n2a(macbuf, nla_data(tb[NL80211_ATTR_MAC]));
                printf("IBSS %s joined\n", macbuf);
@@ -236,6 +304,7 @@ static int print_event(struct nl_msg *msg, void *arg)
        }
 
        return NL_SKIP;
+#undef PARSE_BEACON_CHAN
 }
 
 struct wait_event {
-- 
1.6.3.3

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html