cfg80211: provide channel to join_mesh function

Just like the AP mode patch, instead of setting
the channel and then joining the mesh network,
provide the channel to join the network on to
the join_mesh() function.

Like in AP mode, you can also give the channel
to the join-mesh nl80211 command now.

Unlike AP mode, it picks a default channel if
none was given.

As libertas uses mesh mode interfaces but has
no join_mesh callback and we can't simply break
it, keep some compatibility code for that case
and configure the channel directly for it.

In the non-libertas case, where we store the
channel until join, allow setting it while the
interface is down.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 144 insertions, 15 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8e9d525c4653..f47af8b3185e 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1598,6 +1598,12 @@ static int ieee80211_join_mesh(struct wiphy *wiphy, struct net_device *dev,
         err = copy_mesh_setup(ifmsh, setup);
         if (err)
                 return err;
+
+        err = ieee80211_set_channel(wiphy, dev, setup->channel,
+                                    setup->channel_type);
+        if (err)
+                return err;
+
         ieee80211_start_mesh(sdata);
 
         return 0;
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 8523f3878677..1d3d24126946 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -303,14 +303,17 @@ extern const struct mesh_config default_mesh_config;
 extern const struct mesh_setup default_mesh_setup;
 int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
                          struct net_device *dev,
-                         const struct mesh_setup *setup,
+                         struct mesh_setup *setup,
                          const struct mesh_config *conf);
 int cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
                        struct net_device *dev,
-                       const struct mesh_setup *setup,
+                       struct mesh_setup *setup,
                        const struct mesh_config *conf);
 int cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
                         struct net_device *dev);
+int cfg80211_set_mesh_freq(struct cfg80211_registered_device *rdev,
+                           struct wireless_dev *wdev, int freq,
+                           enum nl80211_channel_type channel_type);
 
 /* MLME */
 int __cfg80211_mlme_auth(struct cfg80211_registered_device *rdev,
diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
index 2749cb86b462..2e3b700eba32 100644
--- a/net/wireless/mesh.c
+++ b/net/wireless/mesh.c
@@ -65,6 +65,9 @@ const struct mesh_config default_mesh_config = {
 };
 
 const struct mesh_setup default_mesh_setup = {
+        /* cfg80211_join_mesh() will pick a channel if needed */
+        .channel = NULL,
+        .channel_type = NL80211_CHAN_NO_HT,
         .sync_method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET,
         .path_sel_proto = IEEE80211_PATH_PROTOCOL_HWMP,
         .path_metric = IEEE80211_PATH_METRIC_AIRTIME,
@@ -75,7 +78,7 @@ const struct mesh_setup default_mesh_setup = {
 
 int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
                          struct net_device *dev,
-                         const struct mesh_setup *setup,
+                         struct mesh_setup *setup,
                          const struct mesh_config *conf)
 {
         struct wireless_dev *wdev = dev->ieee80211_ptr;
@@ -101,6 +104,51 @@ int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
         if (!rdev->ops->join_mesh)
                 return -EOPNOTSUPP;
 
+        if (!setup->channel) {
+                /* if no channel explicitly given, use preset channel */
+                setup->channel = wdev->preset_chan;
+                setup->channel_type = wdev->preset_chantype;
+        }
+
+        if (!setup->channel) {
+                /* if we don't have that either, use the first usable channel */
+                enum ieee80211_band band;
+
+                for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+                        struct ieee80211_supported_band *sband;
+                        struct ieee80211_channel *chan;
+                        int i;
+
+                        sband = rdev->wiphy.bands[band];
+                        if (!sband)
+                                continue;
+
+                        for (i = 0; i < sband->n_channels; i++) {
+                                chan = &sband->channels[i];
+                                if (chan->flags & (IEEE80211_CHAN_NO_IBSS |
+                                                   IEEE80211_CHAN_PASSIVE_SCAN |
+                                                   IEEE80211_CHAN_DISABLED |
+                                                   IEEE80211_CHAN_RADAR))
+                                        continue;
+                                setup->channel = chan;
+                                break;
+                        }
+
+                        if (setup->channel)
+                                break;
+                }
+
+                /* no usable channel ... */
+                if (!setup->channel)
+                        return -EINVAL;
+
+                setup->channel_type = NL80211_CHAN_NO_HT;
+        }
+
+        if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, setup->channel,
+                                          setup->channel_type))
+                return -EINVAL;
+
         err = rdev->ops->join_mesh(&rdev->wiphy, dev, conf, setup);
         if (!err) {
                 memcpy(wdev->ssid, setup->mesh_id, setup->mesh_id_len);
@@ -112,7 +160,7 @@ int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
 
 int cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
                        struct net_device *dev,
-                       const struct mesh_setup *setup,
+                       struct mesh_setup *setup,
                        const struct mesh_config *conf)
 {
         struct wireless_dev *wdev = dev->ieee80211_ptr;
@@ -125,6 +173,45 @@ int cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
         return err;
 }
 
+int cfg80211_set_mesh_freq(struct cfg80211_registered_device *rdev,
+                           struct wireless_dev *wdev, int freq,
+                           enum nl80211_channel_type channel_type)
+{
+        struct ieee80211_channel *channel;
+
+        /*
+         * Workaround for libertas (only!), it puts the interface
+         * into mesh mode but doesn't implement join_mesh. Instead,
+         * it is configured via sysfs and then joins the mesh when
+         * you set the channel. Note that the libertas mesh isn't
+         * compatible with 802.11 mesh.
+         */
+        if (!rdev->ops->join_mesh) {
+                int err;
+
+                if (!netif_running(wdev->netdev))
+                        return -ENETDOWN;
+                wdev_lock(wdev);
+                err = cfg80211_set_freq(rdev, wdev, freq, channel_type);
+                wdev_unlock(wdev);
+
+                return err;
+        }
+
+        if (wdev->mesh_id_len)
+                return -EBUSY;
+
+        channel = rdev_freq_to_chan(rdev, freq, channel_type);
+        if (!channel || !cfg80211_can_beacon_sec_chan(&rdev->wiphy,
+                                                      channel,
+                                                      channel_type)) {
+                return -EINVAL;
+        }
+        wdev->preset_chan = channel;
+        wdev->preset_chantype = channel_type;
+        return 0;
+}
+
 void cfg80211_notify_new_peer_candidate(struct net_device *dev,
                 const u8 *macaddr, const u8* ie, u8 ie_len, gfp_t gfp)
 {
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 089a5204dad5..b22f1f876881 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -921,7 +921,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                 if (nla_put_u32(msg, i, NL80211_CMD_SET_WIPHY_NETNS))
                         goto nla_put_failure;
         }
-        if (dev->ops->set_channel || dev->ops->start_ap) {
+        if (dev->ops->set_channel || dev->ops->start_ap ||
+            dev->ops->join_mesh) {
                 i++;
                 if (nla_put_u32(msg, i, NL80211_CMD_SET_CHANNEL))
                         goto nla_put_failure;
@@ -1166,17 +1167,19 @@ static int parse_txq_params(struct nlattr *tb[],
 static bool nl80211_can_set_dev_channel(struct wireless_dev *wdev)
 {
         /*
-         * You can only set the channel explicitly for AP and
-         * mesh type interfaces; all others have their channel
-         * managed via their respective "establish a connection"
-         * command (connect, join, ...)
+         * You can only set the channel explicitly for WDS interfaces,
+         * all others have their channel managed via their respective
+         * "establish a connection" command (connect, join, ...)
+         *
+         * For AP/GO and mesh mode, the channel can be set with the
+         * channel userspace API, but is only stored and passed to the
+         * low-level driver when the AP starts or the mesh is joined.
+         * This is for backward compatibility, userspace can also give
+         * the channel in the start-ap or join-mesh commands instead.
          *
          * Monitors are special as they are normally slaved to
          * whatever else is going on, so they behave as though
          * you tried setting the wiphy channel itself.
-         *
-         * For AP/GO modes, it's only for compatibility, you can
-         * also give the channel to the start-AP command.
          */
         return !wdev ||
                 wdev->iftype == NL80211_IFTYPE_AP ||
@@ -1246,6 +1249,9 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
                 wdev->preset_chantype = channel_type;
                 result = 0;
                 break;
+        case NL80211_IFTYPE_MESH_POINT:
+                result = cfg80211_set_mesh_freq(rdev, wdev, freq, channel_type);
+                break;
         default:
                 wdev_lock(wdev);
                 result = cfg80211_set_freq(rdev, wdev, freq, channel_type);
@@ -1335,8 +1341,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                 result = 0;
 
                 mutex_lock(&rdev->mtx);
-        } else if (netif_running(netdev) &&
-                   nl80211_can_set_dev_channel(netdev->ieee80211_ptr))
+        } else if (nl80211_can_set_dev_channel(netdev->ieee80211_ptr))
                 wdev = netdev->ieee80211_ptr;
         else
                 wdev = NULL;
@@ -6080,6 +6085,24 @@ static int nl80211_join_mesh(struct sk_buff *skb, struct genl_info *info)
                         return err;
         }
 
+        if (info->attrs[NL80211_ATTR_WIPHY_FREQ]) {
+                enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
+
+                if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE] &&
+                    !nl80211_valid_channel_type(info, &channel_type))
+                        return -EINVAL;
+
+                setup.channel = rdev_freq_to_chan(rdev,
+                        nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]),
+                        channel_type);
+                if (!setup.channel)
+                        return -EINVAL;
+                setup.channel_type = channel_type;
+        } else {
+                /* cfg80211_join_mesh() will sort it out */
+                setup.channel = NULL;
+        }
+
         return cfg80211_join_mesh(rdev, dev, &setup, &cfg);
 }
 
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index b082fcc26f06..faeb03548aa4 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -796,7 +796,6 @@ static int cfg80211_wext_siwfreq(struct net_device *dev,
         case NL80211_IFTYPE_ADHOC:
                 return cfg80211_ibss_wext_siwfreq(dev, info, wextfreq, extra);
         case NL80211_IFTYPE_MONITOR:
-        case NL80211_IFTYPE_MESH_POINT:
                 freq = cfg80211_wext_freq(wdev->wiphy, wextfreq);
                 if (freq < 0)
                         return freq;
@@ -808,6 +807,17 @@ static int cfg80211_wext_siwfreq(struct net_device *dev,
                 wdev_unlock(wdev);
                 mutex_unlock(&rdev->devlist_mtx);
                 return err;
+        case NL80211_IFTYPE_MESH_POINT:
+                freq = cfg80211_wext_freq(wdev->wiphy, wextfreq);
+                if (freq < 0)
+                        return freq;
+                if (freq == 0)
+                        return -EINVAL;
+                mutex_lock(&rdev->devlist_mtx);
+                err = cfg80211_set_mesh_freq(rdev, wdev, freq,
+                                             NL80211_CHAN_NO_HT);
+                mutex_unlock(&rdev->devlist_mtx);
+                return err;
         default:
                 return -EOPNOTSUPP;
         }