cfg80211: introduce TDLS channel switch commands

Introduce commands to initiate and cancel TDLS channel-switching. Once
TDLS channel-switching is started, the lower level driver is responsible
for continually initiating channel-switch operations and returning to
the base (AP) channel to listen for beacons from time to time.

Upon cancellation of the channel-switch all communication between the
relevant TDLS peers will continue on the base channel.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

6 files changed, 211 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 220d5f5f1aca..8d04dfef32bf 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2367,6 +2367,12 @@ struct cfg80211_qos_map {
  *      (invoked with the wireless_dev mutex held)
  * @leave_ocb: leave the current OCB network
  *      (invoked with the wireless_dev mutex held)
+ *
+ * @tdls_channel_switch: Start channel-switching with a TDLS peer. The driver
+ *      is responsible for continually initiating channel-switching operations
+ *      and returning to the base channel for communication with the AP.
+ * @tdls_cancel_channel_switch: Stop channel-switching with a TDLS peer. Both
+ *      peers must be on the base channel when the call completes.
  */
 struct cfg80211_ops {
         int     (*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -2622,6 +2628,14 @@ struct cfg80211_ops {
                              u16 admitted_time);
         int     (*del_tx_ts)(struct wiphy *wiphy, struct net_device *dev,
                              u8 tsid, const u8 *peer);
+
+        int     (*tdls_channel_switch)(struct wiphy *wiphy,
+                                       struct net_device *dev,
+                                       const u8 *addr, u8 oper_class,
+                                       struct cfg80211_chan_def *chandef);
+        void    (*tdls_cancel_channel_switch)(struct wiphy *wiphy,
+                                              struct net_device *dev,
+                                              const u8 *addr);
 };
 
 /*
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index ccdeef28d672..365db67ca71d 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -762,6 +762,18 @@
  * @NL80211_CMD_LEAVE_OCB: Leave the OCB network -- no special arguments, the
  *      network is determined by the network interface.
  *
+ * @NL80211_CMD_TDLS_CHANNEL_SWITCH: Start channel-switching with a TDLS peer,
+ *      identified by the %NL80211_ATTR_MAC parameter. A target channel is
+ *      provided via %NL80211_ATTR_WIPHY_FREQ and other attributes determining
+ *      channel width/type. The target operating class is given via
+ *      %NL80211_ATTR_OPER_CLASS.
+ *      The driver is responsible for continually initiating channel-switching
+ *      operations and returning to the base channel for communication with the
+ *      AP.
+ * @NL80211_CMD_TDLS_CANCEL_CHANNEL_SWITCH: Stop channel-switching with a TDLS
+ *      peer given by %NL80211_ATTR_MAC. Both peers must be on the base channel
+ *      when this command completes.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -943,6 +955,9 @@ enum nl80211_commands {
 
         NL80211_CMD_CH_SWITCH_STARTED_NOTIFY,
 
+        NL80211_CMD_TDLS_CHANNEL_SWITCH,
+        NL80211_CMD_TDLS_CANCEL_CHANNEL_SWITCH,
+
         /* add new commands above here */
 
         /* used to define NL80211_CMD_MAX below */
@@ -1669,6 +1684,8 @@ enum nl80211_commands {
  * @NL80211_ATTR_SMPS_MODE: SMPS mode to use (ap mode). see
  *      &enum nl80211_smps_mode.
  *
+ * @NL80211_ATTR_OPER_CLASS: operating class
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -2021,6 +2038,8 @@ enum nl80211_attrs {
 
         NL80211_ATTR_SMPS_MODE,
 
+        NL80211_ATTR_OPER_CLASS,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/core.c b/net/wireless/core.c
index a4d27927aba2..4c2e501203d1 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -541,6 +541,10 @@ int wiphy_register(struct wiphy *wiphy)
                     !wiphy->wowlan->tcp))
                 return -EINVAL;
 #endif
+        if (WARN_ON((wiphy->features & NL80211_FEATURE_TDLS_CHANNEL_SWITCH) &&
+                    (!rdev->ops->tdls_channel_switch ||
+                     !rdev->ops->tdls_cancel_channel_switch)))
+                return -EINVAL;
 
         if (WARN_ON(wiphy->coalesce &&
                     (!wiphy->coalesce->n_rules ||
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d0a8361b3395..27666f5e5050 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -9658,6 +9658,98 @@ static int nl80211_del_tx_ts(struct sk_buff *skb, struct genl_info *info)
         return err;
 }
 
+static int nl80211_tdls_channel_switch(struct sk_buff *skb,
+                                       struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct wireless_dev *wdev = dev->ieee80211_ptr;
+        struct cfg80211_chan_def chandef = {};
+        const u8 *addr;
+        u8 oper_class;
+        int err;
+
+        if (!rdev->ops->tdls_channel_switch ||
+            !(rdev->wiphy.features & NL80211_FEATURE_TDLS_CHANNEL_SWITCH))
+                return -EOPNOTSUPP;
+
+        switch (dev->ieee80211_ptr->iftype) {
+        case NL80211_IFTYPE_STATION:
+        case NL80211_IFTYPE_P2P_CLIENT:
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        if (!info->attrs[NL80211_ATTR_MAC] ||
+            !info->attrs[NL80211_ATTR_OPER_CLASS])
+                return -EINVAL;
+
+        err = nl80211_parse_chandef(rdev, info, &chandef);
+        if (err)
+                return err;
+
+        /*
+         * Don't allow wide channels on the 2.4Ghz band, as per IEEE802.11-2012
+         * section 10.22.6.2.1. Disallow 5/10Mhz channels as well for now, the
+         * specification is not defined for them.
+         */
+        if (chandef.chan->band == IEEE80211_BAND_2GHZ &&
+            chandef.width != NL80211_CHAN_WIDTH_20_NOHT &&
+            chandef.width != NL80211_CHAN_WIDTH_20)
+                return -EINVAL;
+
+        /* we will be active on the TDLS link */
+        if (!cfg80211_reg_can_beacon(&rdev->wiphy, &chandef, wdev->iftype))
+                return -EINVAL;
+
+        /* don't allow switching to DFS channels */
+        if (cfg80211_chandef_dfs_required(wdev->wiphy, &chandef, wdev->iftype))
+                return -EINVAL;
+
+        addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
+        oper_class = nla_get_u8(info->attrs[NL80211_ATTR_OPER_CLASS]);
+
+        wdev_lock(wdev);
+        err = rdev_tdls_channel_switch(rdev, dev, addr, oper_class, &chandef);
+        wdev_unlock(wdev);
+
+        return err;
+}
+
+static int nl80211_tdls_cancel_channel_switch(struct sk_buff *skb,
+                                              struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct wireless_dev *wdev = dev->ieee80211_ptr;
+        const u8 *addr;
+
+        if (!rdev->ops->tdls_channel_switch ||
+            !rdev->ops->tdls_cancel_channel_switch ||
+            !(rdev->wiphy.features & NL80211_FEATURE_TDLS_CHANNEL_SWITCH))
+                return -EOPNOTSUPP;
+
+        switch (dev->ieee80211_ptr->iftype) {
+        case NL80211_IFTYPE_STATION:
+        case NL80211_IFTYPE_P2P_CLIENT:
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        if (!info->attrs[NL80211_ATTR_MAC])
+                return -EINVAL;
+
+        addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+        wdev_lock(wdev);
+        rdev_tdls_cancel_channel_switch(rdev, dev, addr);
+        wdev_unlock(wdev);
+
+        return 0;
+}
+
 #define NL80211_FLAG_NEED_WIPHY         0x01
 #define NL80211_FLAG_NEED_NETDEV        0x02
 #define NL80211_FLAG_NEED_RTNL          0x04
@@ -10456,6 +10548,22 @@ static const struct genl_ops nl80211_ops[] = {
                 .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
                                   NL80211_FLAG_NEED_RTNL,
         },
+        {
+                .cmd = NL80211_CMD_TDLS_CHANNEL_SWITCH,
+                .doit = nl80211_tdls_channel_switch,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
+        {
+                .cmd = NL80211_CMD_TDLS_CANCEL_CHANNEL_SWITCH,
+                .doit = nl80211_tdls_cancel_channel_switch,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
 };
 
 /* notification functions */
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 1b3864cd50ca..35cfb7134bdb 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -993,4 +993,28 @@ rdev_del_tx_ts(struct cfg80211_registered_device *rdev,
         return ret;
 }
 
+static inline int
+rdev_tdls_channel_switch(struct cfg80211_registered_device *rdev,
+                         struct net_device *dev, const u8 *addr,
+                         u8 oper_class, struct cfg80211_chan_def *chandef)
+{
+        int ret;
+
+        trace_rdev_tdls_channel_switch(&rdev->wiphy, dev, addr, oper_class,
+                                       chandef);
+        ret = rdev->ops->tdls_channel_switch(&rdev->wiphy, dev, addr,
+                                             oper_class, chandef);
+        trace_rdev_return_int(&rdev->wiphy, ret);
+        return ret;
+}
+
+static inline void
+rdev_tdls_cancel_channel_switch(struct cfg80211_registered_device *rdev,
+                                struct net_device *dev, const u8 *addr)
+{
+        trace_rdev_tdls_cancel_channel_switch(&rdev->wiphy, dev, addr);
+        rdev->ops->tdls_cancel_channel_switch(&rdev->wiphy, dev, addr);
+        trace_rdev_return_void(&rdev->wiphy);
+}
+
 #endif /* __CFG80211_RDEV_OPS */
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 6e25370d3ce7..ad38910f7036 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2032,6 +2032,48 @@ TRACE_EVENT(rdev_del_tx_ts,
                   WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(peer), __entry->tsid)
 );
 
+TRACE_EVENT(rdev_tdls_channel_switch,
+        TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+                 const u8 *addr, u8 oper_class,
+                 struct cfg80211_chan_def *chandef),
+        TP_ARGS(wiphy, netdev, addr, oper_class, chandef),
+        TP_STRUCT__entry(
+                WIPHY_ENTRY
+                NETDEV_ENTRY
+                MAC_ENTRY(addr)
+                __field(u8, oper_class)
+                CHAN_DEF_ENTRY
+        ),
+        TP_fast_assign(
+                WIPHY_ASSIGN;
+                NETDEV_ASSIGN;
+                MAC_ASSIGN(addr, addr);
+                CHAN_DEF_ASSIGN(chandef);
+        ),
+        TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT
+                  " oper class %d, " CHAN_DEF_PR_FMT,
+                  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(addr),
+                  __entry->oper_class, CHAN_DEF_PR_ARG)
+);
+
+TRACE_EVENT(rdev_tdls_cancel_channel_switch,
+        TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+                 const u8 *addr),
+        TP_ARGS(wiphy, netdev, addr),
+        TP_STRUCT__entry(
+                WIPHY_ENTRY
+                NETDEV_ENTRY
+                MAC_ENTRY(addr)
+        ),
+        TP_fast_assign(
+                WIPHY_ASSIGN;
+                NETDEV_ASSIGN;
+                MAC_ASSIGN(addr, addr);
+        ),
+        TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT,
+                  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(addr))
+);
+
 /*************************************************************
  *           cfg80211 exported functions traces              *
  *************************************************************/