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>

4 files changed, 178 insertions, 0 deletions

diff --git a/net/wireless/core.c b/net/wireless/core.c
index a4d2792..4c2e501 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 d0a8361..27666f5e 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 1b3864c..35cfb71 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 6e25370..ad38910 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		     *
  *************************************************************/