nl80211: Add CMD_CONTROL_PORT_FRAME API

This commit also adds cfg80211_rx_control_port function.  This is used
to generate a CMD_CONTROL_PORT_FRAME event out to userspace.  The
conn_owner_nlportid is used as the unicast destination.  This means that
userspace must specify NL80211_ATTR_SOCKET_OWNER flag if control port
over nl80211 routing is requested in NL80211_CMD_CONNECT,
NL80211_CMD_ASSOCIATE, NL80211_CMD_START_AP or IBSS/mesh join.

Signed-off-by: Denis Kenzior <denkenz@gmail.com>
[johannes: fix return value of cfg80211_rx_control_port()]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 114 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index bfe174896fcf..df145f76adad 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -5722,6 +5722,28 @@ void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
 
 
 /**
+ * cfg80211_rx_control_port - notification about a received control port frame
+ * @dev: The device the frame matched to
+ * @buf: control port frame
+ * @len: length of the frame data
+ * @addr: The peer from which the frame was received
+ * @proto: frame protocol, typically PAE or Pre-authentication
+ * @unencrypted: Whether the frame was received unencrypted
+ *
+ * This function is used to inform userspace about a received control port
+ * frame.  It should only be used if userspace indicated it wants to receive
+ * control port frames over nl80211.
+ *
+ * The frame is the data portion of the 802.3 or 802.11 data frame with all
+ * network layer headers removed (e.g. the raw EAPoL frame).
+ *
+ * Return: %true if the frame was passed to userspace
+ */
+bool cfg80211_rx_control_port(struct net_device *dev,
+                              const u8 *buf, size_t len,
+                              const u8 *addr, u16 proto, bool unencrypted);
+
+/**
  * cfg80211_cqm_rssi_notify - connection quality monitoring rssi event
  * @dev: network device
  * @rssi_event: the triggered RSSI event
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 9ea3d6039eca..6a3cc7a635b5 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -990,6 +990,17 @@
  *      &NL80211_CMD_CONNECT or &NL80211_CMD_ROAM. If the 4 way handshake failed
  *      &NL80211_CMD_DISCONNECT should be indicated instead.
  *
+ * @NL80211_CMD_CONTROL_PORT_FRAME: Control Port (e.g. PAE) frame TX request
+ *      and RX notification.  This command is used both as a request to transmit
+ *      a control port frame and as a notification that a control port frame
+ *      has been received. %NL80211_ATTR_FRAME is used to specify the
+ *      frame contents.  The frame is the raw EAPoL data, without ethernet or
+ *      802.11 headers.
+ *      When used as an event indication %NL80211_ATTR_CONTROL_PORT_ETHERTYPE,
+ *      %NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT and %NL80211_ATTR_MAC are added
+ *      indicating the protocol type of the received frame; whether the frame
+ *      was received unencrypted and the MAC address of the peer respectively.
+ *
  * @NL80211_CMD_RELOAD_REGDB: Request that the regdb firmware file is reloaded.
  *
  * @NL80211_CMD_EXTERNAL_AUTH: This interface is exclusively defined for host
@@ -1228,6 +1239,8 @@ enum nl80211_commands {
 
         NL80211_CMD_STA_OPMODE_CHANGED,
 
+        NL80211_CMD_CONTROL_PORT_FRAME,
+
         /* add new commands above here */
 
         /* used to define NL80211_CMD_MAX below */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index cfaf2aeb9783..0870447fbd55 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -14553,6 +14553,64 @@ void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
 }
 EXPORT_SYMBOL(cfg80211_mgmt_tx_status);
 
+static int __nl80211_rx_control_port(struct net_device *dev,
+                                     const u8 *buf, size_t len,
+                                     const u8 *addr, u16 proto,
+                                     bool unencrypted, gfp_t gfp)
+{
+        struct wireless_dev *wdev = dev->ieee80211_ptr;
+        struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
+        struct sk_buff *msg;
+        void *hdr;
+        u32 nlportid = READ_ONCE(wdev->conn_owner_nlportid);
+
+        if (!nlportid)
+                return -ENOENT;
+
+        msg = nlmsg_new(100 + len, gfp);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_CONTROL_PORT_FRAME);
+        if (!hdr) {
+                nlmsg_free(msg);
+                return -ENOBUFS;
+        }
+
+        if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
+            nla_put_u32(msg, NL80211_ATTR_IFINDEX, dev->ifindex) ||
+            nla_put_u64_64bit(msg, NL80211_ATTR_WDEV, wdev_id(wdev),
+                              NL80211_ATTR_PAD) ||
+            nla_put(msg, NL80211_ATTR_FRAME, len, buf) ||
+            nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, addr) ||
+            nla_put_u16(msg, NL80211_ATTR_CONTROL_PORT_ETHERTYPE, proto) ||
+            (unencrypted && nla_put_flag(msg,
+                                         NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT)))
+                goto nla_put_failure;
+
+        genlmsg_end(msg, hdr);
+
+        return genlmsg_unicast(wiphy_net(&rdev->wiphy), msg, nlportid);
+
+ nla_put_failure:
+        nlmsg_free(msg);
+        return -ENOBUFS;
+}
+
+bool cfg80211_rx_control_port(struct net_device *dev,
+                              const u8 *buf, size_t len,
+                              const u8 *addr, u16 proto, bool unencrypted)
+{
+        int ret;
+
+        trace_cfg80211_rx_control_port(dev, buf, len, addr, proto, unencrypted);
+        ret = __nl80211_rx_control_port(dev, buf, len, addr, proto,
+                                        unencrypted, GFP_ATOMIC);
+        trace_cfg80211_return_bool(ret == 0);
+        return ret == 0;
+}
+EXPORT_SYMBOL(cfg80211_rx_control_port);
+
 static struct sk_buff *cfg80211_prepare_cqm(struct net_device *dev,
                                             const char *mac, gfp_t gfp)
 {
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 5152938b358d..42fd338f879e 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2600,6 +2600,27 @@ TRACE_EVENT(cfg80211_mgmt_tx_status,
                   WDEV_PR_ARG, __entry->cookie, BOOL_TO_STR(__entry->ack))
 );
 
+TRACE_EVENT(cfg80211_rx_control_port,
+        TP_PROTO(struct net_device *netdev, const u8 *buf, size_t len,
+                 const u8 *addr, u16 proto, bool unencrypted),
+        TP_ARGS(netdev, buf, len, addr, proto, unencrypted),
+        TP_STRUCT__entry(
+                NETDEV_ENTRY
+                MAC_ENTRY(addr)
+                __field(u16, proto)
+                __field(bool, unencrypted)
+        ),
+        TP_fast_assign(
+                NETDEV_ASSIGN;
+                MAC_ASSIGN(addr, addr);
+                __entry->proto = proto;
+                __entry->unencrypted = unencrypted;
+        ),
+        TP_printk(NETDEV_PR_FMT ", " MAC_PR_FMT " proto: 0x%x, unencrypted: %s",
+                  NETDEV_PR_ARG, MAC_PR_ARG(addr),
+                  __entry->proto, BOOL_TO_STR(__entry->unencrypted))
+);
+
 TRACE_EVENT(cfg80211_cqm_rssi_notify,
         TP_PROTO(struct net_device *netdev,
                  enum nl80211_cqm_rssi_threshold_event rssi_event,