nl80211: Separate channel noise fetch from scan result processing

This untangles the NL80211_CMD_GET_SURVEY handler loop from
NL80211_CMD_GET_SCAN processing so that the per-channel noise
information can be fetched with a common function to a local data
structure that can then be easily used to update individual scan results
(a single BSS) instead of having to go through a full set of scan
results. This is a step towards optimizing scan result fetching without
having to allocate memory for all entries at the same time.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

diff --git a/src/drivers/driver_nl80211_scan.c b/src/drivers/driver_nl80211_scan.c
index e50323106448f64c716cc03fc4756642ce17b6c7..b46c7f1b3a971c40d5c374f3591631f0a2509098 100644 (file)
--- a/src/drivers/driver_nl80211_scan.c
+++ b/src/drivers/driver_nl80211_scan.c
@@ -20,6 +20,14 @@
 #include "driver_nl80211.h"
 
 
+#define MAX_NL80211_NOISE_FREQS 50
+
+struct nl80211_noise_info {
+       u32 freq[MAX_NL80211_NOISE_FREQS];
+       s8 noise[MAX_NL80211_NOISE_FREQS];
+       unsigned int count;
+};
+
 static int get_noise_for_scan_results(struct nl_msg *msg, void *arg)
 {
        struct nlattr *tb[NL80211_ATTR_MAX + 1];
@@ -29,9 +37,10 @@ static int get_noise_for_scan_results(struct nl_msg *msg, void *arg)
                [NL80211_SURVEY_INFO_FREQUENCY] = { .type = NLA_U32 },
                [NL80211_SURVEY_INFO_NOISE] = { .type = NLA_U8 },
        };
-       struct wpa_scan_results *scan_results = arg;
-       struct wpa_scan_res *scan_res;
-       size_t i;
+       struct nl80211_noise_info *info = arg;
+
+       if (info->count >= MAX_NL80211_NOISE_FREQS)
+               return NL_STOP;
 
        nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
                  genlmsg_attrlen(gnlh, 0), NULL);
@@ -55,33 +64,24 @@ static int get_noise_for_scan_results(struct nl_msg *msg, void *arg)
        if (!sinfo[NL80211_SURVEY_INFO_FREQUENCY])
                return NL_SKIP;
 
-       for (i = 0; i < scan_results->num; ++i) {
-               scan_res = scan_results->res[i];
-               if (!scan_res)
-                       continue;
-               if ((int) nla_get_u32(sinfo[NL80211_SURVEY_INFO_FREQUENCY]) !=
-                   scan_res->freq)
-                       continue;
-               if (!(scan_res->flags & WPA_SCAN_NOISE_INVALID))
-                       continue;
-               scan_res->noise = (s8)
-                       nla_get_u8(sinfo[NL80211_SURVEY_INFO_NOISE]);
-               scan_res->flags &= ~WPA_SCAN_NOISE_INVALID;
-       }
+       info->freq[info->count] =
+               nla_get_u32(sinfo[NL80211_SURVEY_INFO_FREQUENCY]);
+       info->noise[info->count] =
+               (s8) nla_get_u8(sinfo[NL80211_SURVEY_INFO_NOISE]);
+       info->count++;
 
        return NL_SKIP;
 }
 
 
 static int nl80211_get_noise_for_scan_results(
-       struct wpa_driver_nl80211_data *drv,
-       struct wpa_scan_results *scan_res)
+       struct wpa_driver_nl80211_data *drv, struct nl80211_noise_info *info)
 {
        struct nl_msg *msg;
 
+       os_memset(info, 0, sizeof(*info));
        msg = nl80211_drv_msg(drv, NLM_F_DUMP, NL80211_CMD_GET_SURVEY);
-       return send_and_recv_msgs(drv, msg, get_noise_for_scan_results,
-                                 scan_res);
+       return send_and_recv_msgs(drv, msg, get_noise_for_scan_results, info);
 }
 
 
@@ -853,6 +853,21 @@ static void wpa_driver_nl80211_check_bss_status(
 }
 
 
+static void nl80211_update_scan_res_noise(struct wpa_scan_res *res,
+                                         struct nl80211_noise_info *info)
+{
+       unsigned int i;
+
+       for (i = 0; res && i < info->count; i++) {
+               if ((int) info->freq[i] != res->freq ||
+                   !(res->flags & WPA_SCAN_NOISE_INVALID))
+                       continue;
+               res->noise = info->noise[i];
+               res->flags &= ~WPA_SCAN_NOISE_INVALID;
+       }
+}
+
+
 static struct wpa_scan_results *
 nl80211_get_scan_results(struct wpa_driver_nl80211_data *drv)
 {
@@ -874,9 +889,17 @@ nl80211_get_scan_results(struct wpa_driver_nl80211_data *drv)
        arg.res = res;
        ret = send_and_recv_msgs(drv, msg, bss_info_handler, &arg);
        if (ret == 0) {
+               struct nl80211_noise_info info;
+
                wpa_printf(MSG_DEBUG, "nl80211: Received scan results (%lu "
                           "BSSes)", (unsigned long) res->num);
-               nl80211_get_noise_for_scan_results(drv, res);
+               if (nl80211_get_noise_for_scan_results(drv, &info) == 0) {
+                       size_t i;
+
+                       for (i = 0; i < res->num; ++i)
+                               nl80211_update_scan_res_noise(res->res[i],
+                                                             &info);
+               }
                return res;
        }
        wpa_printf(MSG_DEBUG, "nl80211: Scan result fetch failed: ret=%d "