wifi: cfg80211/mac80211: Support control port TX from specific link

In case of authentication with a legacy station, link addressed EAPOL
frames should be sent. Support it.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -4580,7 +4580,7 @@ struct cfg80211_ops {
 				   struct net_device *dev,
 				   const u8 *buf, size_t len,
 				   const u8 *dest, const __be16 proto,
-				   const bool noencrypt,
+				   const bool noencrypt, int link_id,
 				   u64 *cookie);
 
 	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,

net/mac80211/ieee80211_i.h

@@ -1946,7 +1946,7 @@ void ieee80211_clear_fast_xmit(struct sta_info *sta);
 int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len,
 			      const u8 *dest, __be16 proto, bool unencrypted,
-			      u64 *cookie);
+			      int link_id, u64 *cookie);
 int ieee80211_probe_mesh_link(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len);
 

net/mac80211/tx.c

@@ -5674,7 +5674,7 @@ void ieee80211_tx_skb_tid(struct ieee80211_sub_if_data *sdata,
 int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len,
 			      const u8 *dest, __be16 proto, bool unencrypted,
-			      u64 *cookie)
+			      int link_id, u64 *cookie)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = sdata->local;
@@ -5714,7 +5714,23 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 
 	ehdr = skb_push(skb, sizeof(struct ethhdr));
 	memcpy(ehdr->h_dest, dest, ETH_ALEN);
+
+	if (link_id < 0) {
 		memcpy(ehdr->h_source, sdata->vif.addr, ETH_ALEN);
+	} else {
+		struct ieee80211_bss_conf *link_conf;
+
+		rcu_read_lock();
+		link_conf = rcu_dereference(sdata->vif.link_conf[link_id]);
+		if (!link_conf) {
+			dev_kfree_skb(skb);
+			rcu_read_unlock();
+			return -ENOLINK;
+		}
+		memcpy(ehdr->h_source, link_conf->addr, ETH_ALEN);
+		rcu_read_unlock();
+	}
+
 	ehdr->h_proto = proto;
 
 	skb->dev = dev;

net/wireless/nl80211.c

@@ -15223,6 +15223,7 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 	u16 proto;
 	bool noencrypt;
 	u64 cookie = 0;
+	int link_id;
 	int err;
 
 	if (!wiphy_ext_feature_isset(&rdev->wiphy,
@@ -15271,8 +15272,10 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 	noencrypt =
 		nla_get_flag(info->attrs[NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT]);
 
+	link_id = nl80211_link_id_or_invalid(info->attrs);
+
 	err = rdev_tx_control_port(rdev, dev, buf, len,
-				   dest, cpu_to_be16(proto), noencrypt,
+				   dest, cpu_to_be16(proto), noencrypt, link_id,
 				   dont_wait_for_ack ? NULL : &cookie);
 	if (!err && !dont_wait_for_ack)
 		nl_set_extack_cookie_u64(info->extack, cookie);

net/wireless/rdev-ops.h

@@ -746,13 +746,14 @@ static inline int rdev_tx_control_port(struct cfg80211_registered_device *rdev,
 				       struct net_device *dev,
 				       const void *buf, size_t len,
 				       const u8 *dest, __be16 proto,
-				       const bool noencrypt, u64 *cookie)
+				       const bool noencrypt, int link,
+				       u64 *cookie)
 {
 	int ret;
 	trace_rdev_tx_control_port(&rdev->wiphy, dev, buf, len,
-				   dest, proto, noencrypt);
+				   dest, proto, noencrypt, link);
 	ret = rdev->ops->tx_control_port(&rdev->wiphy, dev, buf, len,
-					 dest, proto, noencrypt, cookie);
+					 dest, proto, noencrypt, link, cookie);
 	if (cookie)
 		trace_rdev_return_int_cookie(&rdev->wiphy, ret, *cookie);
 	else

net/wireless/trace.h

@@ -2015,14 +2015,15 @@ TRACE_EVENT(rdev_mgmt_tx,
 TRACE_EVENT(rdev_tx_control_port,
 	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
 		 const u8 *buf, size_t len, const u8 *dest, __be16 proto,
-		 bool unencrypted),
+		 bool unencrypted, int link_id),
-	TP_ARGS(wiphy, netdev, buf, len, dest, proto, unencrypted),
+	TP_ARGS(wiphy, netdev, buf, len, dest, proto, unencrypted, link_id),
 	TP_STRUCT__entry(
 		WIPHY_ENTRY
 		NETDEV_ENTRY
 		MAC_ENTRY(dest)
 		__field(__be16, proto)
 		__field(bool, unencrypted)
+		__field(int, link_id)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
@@ -2030,12 +2031,14 @@ TRACE_EVENT(rdev_tx_control_port,
 		MAC_ASSIGN(dest, dest);
 		__entry->proto = proto;
 		__entry->unencrypted = unencrypted;
+		__entry->link_id = link_id;
 	),
 	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT ","
-		  " proto: 0x%x, unencrypted: %s",
+		  " proto: 0x%x, unencrypted: %s, link: %d",
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(dest),
 		  be16_to_cpu(__entry->proto),
-		  BOOL_TO_STR(__entry->unencrypted))
+		  BOOL_TO_STR(__entry->unencrypted),
+		  __entry->link_id)
 );
 
 TRACE_EVENT(rdev_set_noack_map,