nl80211: Generate 802.11b mode based on 802.11g information

If the phy info from nl80211 does not include 802.11b mode, generate
that mode based on 802.11g information. This allows hw_mode=b to be used
with drivers that support 2.4 GHz band.

diff --git a/hostapd/driver_nl80211.c b/hostapd/driver_nl80211.c
index 90c6728..8543d9a 100644 (file)
--- a/hostapd/driver_nl80211.c
+++ b/hostapd/driver_nl80211.c
@@ -1497,6 +1497,80 @@ static int phy_info_handler(struct nl_msg *msg, void *arg)
        return NL_SKIP;
 }
 
+static struct hostapd_hw_modes *i802_add_11b(struct hostapd_hw_modes *modes,
+                                            u16 *num_modes)
+{
+       u16 m;
+       struct hostapd_hw_modes *mode11g = NULL, *nmodes, *mode;
+       int i, mode11g_idx = -1;
+
+       /* If only 802.11g mode is included, use it to construct matching
+        * 802.11b mode data. */
+
+       for (m = 0; m < *num_modes; m++) {
+               if (modes[m].mode == HOSTAPD_MODE_IEEE80211B)
+                       return modes; /* 802.11b already included */
+               if (modes[m].mode == HOSTAPD_MODE_IEEE80211G)
+                       mode11g_idx = m;
+       }
+
+       if (mode11g_idx < 0)
+               return modes; /* 2.4 GHz band not supported at all */
+
+       nmodes = os_realloc(modes, (*num_modes + 1) * sizeof(*nmodes));
+       if (nmodes == NULL)
+               return modes; /* Could not add 802.11b mode */
+
+       mode = &nmodes[*num_modes];
+       os_memset(mode, 0, sizeof(*mode));
+       (*num_modes)++;
+       modes = nmodes;
+
+       mode->mode = HOSTAPD_MODE_IEEE80211B;
+
+       mode11g = &modes[mode11g_idx];
+       mode->num_channels = mode11g->num_channels;
+       mode->channels = os_malloc(mode11g->num_channels *
+                                  sizeof(struct hostapd_channel_data));
+       if (mode->channels == NULL) {
+               (*num_modes)--;
+               return modes; /* Could not add 802.11b mode */
+       }
+       os_memcpy(mode->channels, mode11g->channels,
+                 mode11g->num_channels * sizeof(struct hostapd_channel_data));
+
+       mode->num_rates = 0;
+       mode->rates = os_malloc(4 * sizeof(struct hostapd_rate_data));
+       if (mode->rates == NULL) {
+               os_free(mode->channels);
+               (*num_modes)--;
+               return modes; /* Could not add 802.11b mode */
+       }
+
+       for (i = 0; i < mode11g->num_rates; i++) {
+               if (mode11g->rates[i].rate > 110 ||
+                   mode11g->rates[i].flags &
+                   (HOSTAPD_RATE_ERP | HOSTAPD_RATE_OFDM))
+                       continue;
+               mode->rates[mode->num_rates] = mode11g->rates[i];
+               mode->num_rates++;
+               if (mode->num_rates == 4)
+                       break;
+       }
+
+       if (mode->num_rates == 0) {
+               os_free(mode->channels);
+               os_free(mode->rates);
+               (*num_modes)--;
+               return modes; /* No 802.11b rates */
+       }
+
+       wpa_printf(MSG_DEBUG, "nl80211: Added 802.11b mode based on 802.11g "
+                  "information");
+
+       return modes;
+}
+
 static struct hostapd_hw_modes *i802_get_hw_feature_data(void *priv,
                                                         u16 *num_modes,
                                                         u16 *flags)
@@ -1521,7 +1595,7 @@ static struct hostapd_hw_modes *i802_get_hw_feature_data(void *priv,
        NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, if_nametoindex(drv->iface));
 
        if (send_and_recv_msgs(drv, msg, phy_info_handler, &result) == 0)
-               return result.modes;
+               return i802_add_11b(result.modes, num_modes);
  nla_put_failure:
        return NULL;
 }