libs/iwinfo: implement *_get_txpwrlist() to obtain valid tx power levels

[project/luci.git] / libs / iwinfo / src / iwinfo_wext.c

diff --git a/libs/iwinfo/src/iwinfo_wext.c b/libs/iwinfo/src/iwinfo_wext.c
index 859bb1f..24be10f 100644 (file)
--- a/libs/iwinfo/src/iwinfo_wext.c
+++ b/libs/iwinfo/src/iwinfo_wext.c
@@ -22,6 +22,8 @@
 #include "iwinfo.h"
 #include "iwinfo_wext.h"
 
+#define LOG10_MAGIC    1.25892541179
+
 static int ioctl_socket = -1;
 
 static double wext_freq2float(const struct iw_freq *in)
@@ -50,6 +52,39 @@ static int wext_freq2mhz(const struct iw_freq *in)
        }
 }
 
+static int wext_dbm2mw(int in)
+{
+       double res = 1.0;
+       int ip = in / 10;
+       int fp = in % 10;
+       int k;
+
+       for(k = 0; k < ip; k++) res *= 10;
+       for(k = 0; k < fp; k++) res *= LOG10_MAGIC;
+
+       return (int)res;
+}
+
+static int wext_mw2dbm(int in)
+{
+       double fin = (double) in;
+       int res = 0;
+
+       while(fin > 10.0)
+       {
+               res += 10;
+               fin /= 10.0;
+       }
+
+       while(fin > 1.000001)
+       {
+               res += 1;
+               fin /= LOG10_MAGIC;
+       }
+
+       return res;
+}
+
 static int wext_ioctl(const char *ifname, int cmd, struct iwreq *wrq)
 {
        /* prepare socket */
@@ -297,6 +332,44 @@ int wext_get_assoclist(const char *ifname, char *buf, int *len)
        return -1;
 }
 
+int wext_get_txpwrlist(const char *ifname, char *buf, int *len)
+{
+       struct iwreq wrq;
+       struct iw_range range;
+       struct iwinfo_txpwrlist_entry entry;
+       int i;
+
+       wrq.u.data.pointer = (caddr_t) &range;
+       wrq.u.data.length  = sizeof(struct iw_range);
+       wrq.u.data.flags   = 0;
+
+       if( (wext_ioctl(ifname, SIOCGIWRANGE, &wrq) >= 0) &&
+           (range.num_txpower > 0) && (range.num_txpower <= IW_MAX_TXPOWER) &&
+           !(range.txpower_capa & IW_TXPOW_RELATIVE)
+       ) {
+               for( i = 0; i < range.num_txpower; i++ )
+               {
+                       if( range.txpower_capa & IW_TXPOW_MWATT )
+                       {
+                               entry.dbm = wext_mw2dbm(range.txpower[i]);
+                               entry.mw  = range.txpower[i];
+                       }
+                       else
+                       {
+                               entry.dbm = range.txpower[i];
+                               entry.mw  = wext_dbm2mw(range.txpower[i]);
+                       }
+
+                       memcpy(&buf[i*sizeof(entry)], &entry, sizeof(entry));
+               }
+
+               *len = i * sizeof(entry);
+               return 0;
+       }
+
+       return -1;      
+}
+
 int wext_get_mbssid_support(const char *ifname, int *buf)
 {
        /* No multi bssid support atm */