feat(nl80211): add method get_noise

This method is used to obtain the noise of the interface.

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

nl80211.c

@@ -75,6 +75,8 @@ int luaopen_eco_core_nl80211(lua_State *L)
     lua_add_constant(L, "CMD_NEW_SCAN_RESULTS", NL80211_CMD_NEW_SCAN_RESULTS);
     lua_add_constant(L, "CMD_SCAN_ABORTED", NL80211_CMD_SCAN_ABORTED);
 
+    lua_add_constant(L, "CMD_GET_SURVEY", NL80211_CMD_GET_SURVEY);
+
     lua_add_constant(L, "CMD_RADAR_DETECT", NL80211_CMD_RADAR_DETECT);
     lua_add_constant(L, "CMD_GET_PROTOCOL_FEATURES", NL80211_CMD_GET_PROTOCOL_FEATURES);
     lua_add_constant(L, "CMD_CH_SWITCH_STARTED_NOTIFY", NL80211_CMD_CH_SWITCH_STARTED_NOTIFY);
@@ -431,6 +433,9 @@ int luaopen_eco_core_nl80211(lua_State *L)
     lua_add_constant(L, "RATE_INFO_EHT_NSS", NL80211_RATE_INFO_EHT_NSS);
     lua_add_constant(L, "RATE_INFO_EHT_GI", NL80211_RATE_INFO_EHT_GI);
 
+    lua_add_constant(L, "SURVEY_INFO_NOISE", NL80211_SURVEY_INFO_NOISE);
+    lua_add_constant(L, "SURVEY_INFO_IN_USE", NL80211_SURVEY_INFO_IN_USE);
+
     lua_add_constant(L, "PROTOCOL_FEATURE_SPLIT_WIPHY_DUMP", NL80211_PROTOCOL_FEATURE_SPLIT_WIPHY_DUMP);
 
     lua_add_constant(L, "BAND_2GHZ", NL80211_BAND_2GHZ);

nl80211.lua

@@ -751,6 +751,64 @@ function M.wait_event(grp_name, timeout, cb, data)
     end
 end
 
+function M.get_noise(ifname)
+    if type(ifname) ~= 'string' then
+        error('invalid ifname')
+    end
+
+    local ifidx = socket.if_nametoindex(ifname)
+    if not ifidx then
+        return nil, 'no dev'
+    end
+
+    local sock, msg = prepare_send_cmd(nl80211.CMD_GET_SURVEY, nl.NLM_F_DUMP)
+    if not sock then
+        return nil, msg
+    end
+
+    msg:put_attr_u32(nl80211.ATTR_IFINDEX, ifidx)
+
+    local ok, err = sock:send(msg)
+    if not ok then
+        return nil, err
+    end
+
+    local noise = 0
+
+    while true do
+        msg, err = sock:recv()
+        if not msg then
+            return nil, err
+        end
+
+        while true do
+            local nlh = msg:next()
+            if not nlh then
+                break
+            end
+
+            if nlh.type == nl.NLMSG_ERROR then
+                err = msg:parse_error()
+                return nil, sys.strerror(-err)
+            end
+
+            if nlh.type == nl.NLMSG_DONE then
+                return noise
+            end
+
+            local attrs = msg:parse_attr(genl.GENLMSGHDR_SIZE)
+            if attrs[nl80211.ATTR_SURVEY_INFO] then
+                local si = nl.parse_attr_nested(attrs[nl80211.ATTR_SURVEY_INFO])
+                if si[nl80211.SURVEY_INFO_NOISE] then
+                    if noise == 0 or si[nl80211.SURVEY_INFO_IN_USE] then
+                        noise = nl.attr_get_s8(si[nl80211.SURVEY_INFO_NOISE])
+                    end
+                end
+            end
+        end
+    end
+end
+
 local function parse_bitrate(attrs)
     local r = {}
     local rate = 0
@@ -967,7 +1025,10 @@ function M.get_station(ifname, mac)
     end
 
     local sinfo = nl.parse_attr_nested(attrs[nl80211.ATTR_STA_INFO])
-    return parse_station(attrs, sinfo)
+    local res = parse_station(attrs, sinfo)
+    res.noise = M.get_noise(ifname) or 0
+
+    return res
 end
 
 function M.get_stations(ifname)
@@ -992,6 +1053,8 @@ function M.get_stations(ifname)
         return nil, err
     end
 
+    local noise = M.get_noise(ifname) or 0
+
     local stations = {}
 
     while true do
@@ -1020,6 +1083,7 @@ function M.get_stations(ifname)
                 local sinfo = nl.parse_attr_nested(attrs[nl80211.ATTR_STA_INFO])
                 local res = parse_station(attrs, sinfo)
                 if res then
+                    res.noise = noise
                     stations[#stations + 1] = res
                 end
             end