[PATCH 1/2] nl80211: add src and dst mac attributes

[PATCH 1/2] nl80211: add src and dst mac attributes

[Markus Theil]

This patch is a prerequisite for handling preauth frames
over nl80211 control port correctly in ap mode.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 include/uapi/linux/nl80211.h | 6 ++++++
 net/wireless/nl80211.c       | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 341e0e8cae46..c284bd828669 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2400,6 +2400,9 @@ enum nl80211_commands {
  * @NL80211_ATTR_VLAN_ID: VLAN ID (1..4094) for the station and VLAN group key
  *	(u16).
  *
+ * @NL80211_ATTR_SRC_MAC: MAC address used in control port over nl80211 transmit
+ * @NL80211_ATTR_DST_MAC: MAC address used in control port over nl80211 receive
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2864,6 +2867,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_VLAN_ID,
 
+	NL80211_ATTR_SRC_MAC,
+	NL80211_ATTR_DST_MAC,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fa3526592c51..467a48b818f9 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -625,6 +625,8 @@ const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_TWT_RESPONDER] = { .type = NLA_FLAG },
 	[NL80211_ATTR_HE_OBSS_PD] = NLA_POLICY_NESTED(he_obss_pd_policy),
 	[NL80211_ATTR_VLAN_ID] = NLA_POLICY_RANGE(NLA_U16, 1, VLAN_N_VID - 2),
+	[NL80211_ATTR_SRC_MAC] = NLA_POLICY_ETH_ADDR,
+	[NL80211_ATTR_DST_MAC] = NLA_POLICY_ETH_ADDR,
 };
 
 /* policy for the key attributes */
-- 
2.24.1

[PATCH 2/2] nl80211: use src and dst addr attribute for control port tx/rx

[Markus Theil]

When using control port over nl80211 in AP mode with
pre-authentication, APs need to forward frames to other
APs defined by their MAC address. Before this patch,
pre-auth frames reaching user space over nl80211 control
port  have no longer any information about the dest attached,
which can be used for forwarding to a controller or injecting
the frame back to a ethernet interface over a AF_PACKET
socket.
Analog problems exist, when forwarding pre-auth frames from
AP -> STA.

This patch therefore uses the NL80211_ATTR_DST_MAC and
NL80211_ATTR_SRC_MAC attributes to provide more context
information when forwarding.
The respective arguments are optional on tx and included on rx.
Therefore unaware existing software is not affected.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 include/net/cfg80211.h       |  3 ++-
 include/uapi/linux/nl80211.h |  5 ++++-
 net/mac80211/ieee80211_i.h   |  3 ++-
 net/mac80211/tx.c            |  5 +++--
 net/wireless/nl80211.c       | 16 +++++++++++++---
 net/wireless/rdev-ops.h      |  8 ++++----
 net/wireless/trace.h         | 27 +++++++++++++++++----------
 7 files changed, 45 insertions(+), 22 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 059524b87c4c..d8e7310d712a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3939,7 +3939,8 @@ struct cfg80211_ops {
 	int	(*tx_control_port)(struct wiphy *wiphy,
 				   struct net_device *dev,
 				   const u8 *buf, size_t len,
-				   const u8 *dest, const __be16 proto,
+				   const u8 *dest, const u8 *src,
+				   const __be16 proto,
 				   const bool noencrypt);
 
 	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index c284bd828669..fea0b34b0dd2 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1039,11 +1039,14 @@
  *	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.
+ *	802.11 headers. An optional %NL80211_ATTR_SRC_MAC can be used to send
+ *	pre-auth frames to STAs on behalf of other APs.
  *	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_ATTR_DST_MAC can be used to forward pre-auth frames in
+ *	userspace while using AP mode.
  *
  * @NL80211_CMD_RELOAD_REGDB: Request that the regdb firmware file is reloaded.
  *
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e3cf24cb4615..e485a7528678 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1786,7 +1786,8 @@ void ieee80211_check_fast_xmit_iface(struct ieee80211_sub_if_data *sdata);
 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);
+			      const u8 *dest, const u8 *src, __be16 proto,
+			      bool unencrypted);
 int ieee80211_probe_mesh_link(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len);
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b31b5078f656..1872d0d13c2d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -5276,7 +5276,8 @@ void __ieee80211_tx_skb_tid_band(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)
+			      const u8 *dest, const u8 *src, __be16 proto,
+			      bool unencrypted)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = sdata->local;
@@ -5307,7 +5308,7 @@ 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);
-	memcpy(ehdr->h_source, sdata->vif.addr, ETH_ALEN);
+	memcpy(ehdr->h_source, src, ETH_ALEN);
 	ehdr->h_proto = proto;
 
 	skb->dev = dev;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 467a48b818f9..42c27ac7742b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -13609,6 +13609,7 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 	const u8 *buf;
 	size_t len;
 	u8 *dest;
+	u8 src[ETH_ALEN];
 	u16 proto;
 	bool noencrypt;
 	int err;
@@ -13646,6 +13647,13 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
+	/* copy src address under wdev_lock, as we may copy wdev_address */
+	if (info->attrs[NL80211_ATTR_SRC_MAC])
+		ether_addr_copy(src,
+				nla_data(info->attrs[NL80211_ATTR_SRC_MAC]));
+	else
+		ether_addr_copy(src, wdev_address(wdev));
+
 	wdev_unlock(wdev);
 
 	buf = nla_data(info->attrs[NL80211_ATTR_FRAME]);
@@ -13656,7 +13664,7 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 		nla_get_flag(info->attrs[NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT]);
 
 	return rdev_tx_control_port(rdev, dev, buf, len,
-				    dest, cpu_to_be16(proto), noencrypt);
+				    dest, src, cpu_to_be16(proto), noencrypt);
 
  out:
 	wdev_unlock(wdev);
@@ -15911,7 +15919,8 @@ static int __nl80211_rx_control_port(struct net_device *dev,
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
 	struct ethhdr *ehdr = eth_hdr(skb);
-	const u8 *addr = ehdr->h_source;
+	const u8 *daddr = ehdr->h_dest;
+	const u8 *saddr = ehdr->h_source;
 	u16 proto = be16_to_cpu(skb->protocol);
 	struct sk_buff *msg;
 	void *hdr;
@@ -15936,7 +15945,8 @@ static int __nl80211_rx_control_port(struct net_device *dev,
 	    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_MAC, ETH_ALEN, addr) ||
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, saddr) ||
+	    nla_put(msg, NL80211_ATTR_DST_MAC, ETH_ALEN, daddr) ||
 	    nla_put_u16(msg, NL80211_ATTR_CONTROL_PORT_ETHERTYPE, proto) ||
 	    (unencrypted && nla_put_flag(msg,
 					 NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT)))
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index e853a4fe6f97..39e6c1db3092 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -730,14 +730,14 @@ static inline int rdev_mgmt_tx(struct cfg80211_registered_device *rdev,
 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)
+				       const u8 *dest, const u8 *src,
+				       __be16 proto, const bool noencrypt)
 {
 	int ret;
 	trace_rdev_tx_control_port(&rdev->wiphy, dev, buf, len,
-				   dest, proto, noencrypt);
+				   dest, src, proto, noencrypt);
 	ret = rdev->ops->tx_control_port(&rdev->wiphy, dev, buf, len,
-					 dest, proto, noencrypt);
+					 dest, src, proto, noencrypt);
 	trace_rdev_return_int(&rdev->wiphy, ret);
 	return ret;
 }
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index d98ad2b3143b..fefa255fd062 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -1923,27 +1923,31 @@ 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,
+		 const u8 *buf, size_t len,
+		 const u8 *dest, const u8 *src, __be16 proto,
 		 bool unencrypted),
-	TP_ARGS(wiphy, netdev, buf, len, dest, proto, unencrypted),
+	TP_ARGS(wiphy, netdev, buf, len, dest, src, proto, unencrypted),
 	TP_STRUCT__entry(
 		WIPHY_ENTRY
 		NETDEV_ENTRY
 		MAC_ENTRY(dest)
-		__field(__be16, proto)
+		MAC_ENTRY(src)
+		__field(u16, proto)
 		__field(bool, unencrypted)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
 		NETDEV_ASSIGN;
 		MAC_ASSIGN(dest, dest);
-		__entry->proto = proto;
+		MAC_ASSIGN(src, src);
+		__entry->proto = be16_to_cpu(proto);
 		__entry->unencrypted = unencrypted;
 	),
-	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT ","
-		  " proto: 0x%x, unencrypted: %s",
-		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(dest),
-		  be16_to_cpu(__entry->proto),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", dest: " MAC_PR_FMT
+		  ", src: " MAC_PR_FMT ", proto: 0x%x, unencrypted: %s",
+		  WIPHY_PR_ARG, NETDEV_PR_ARG,
+		  MAC_PR_ARG(dest), MAC_PR_ARG(src),
+		  __entry->proto,
 		  BOOL_TO_STR(__entry->unencrypted))
 );
 
@@ -2835,6 +2839,7 @@ TRACE_EVENT(cfg80211_rx_control_port,
 	TP_STRUCT__entry(
 		NETDEV_ENTRY
 		__field(int, len)
+		MAC_ENTRY(to)
 		MAC_ENTRY(from)
 		__field(u16, proto)
 		__field(bool, unencrypted)
@@ -2842,12 +2847,14 @@ TRACE_EVENT(cfg80211_rx_control_port,
 	TP_fast_assign(
 		NETDEV_ASSIGN;
 		__entry->len = skb->len;
+		MAC_ASSIGN(to, eth_hdr(skb)->h_dest);
 		MAC_ASSIGN(from, eth_hdr(skb)->h_source);
 		__entry->proto = be16_to_cpu(skb->protocol);
 		__entry->unencrypted = unencrypted;
 	),
-	TP_printk(NETDEV_PR_FMT ", len=%d, " MAC_PR_FMT ", proto: 0x%x, unencrypted: %s",
-		  NETDEV_PR_ARG, __entry->len, MAC_PR_ARG(from),
+	TP_printk(NETDEV_PR_FMT ", len=%d, dest: " MAC_PR_FMT
+		  ", src: " MAC_PR_FMT ", proto: 0x%x, unencrypted: %s",
+		  NETDEV_PR_ARG, __entry->len, MAC_PR_ARG(to), MAC_PR_ARG(from),
 		  __entry->proto, BOOL_TO_STR(__entry->unencrypted))
 );
 
-- 
2.24.1

Re: [PATCH 2/2] nl80211: use src and dst addr attribute for control port tx/rx

[Johannes Berg]

Hi Markus,

First, I think you should squash these two patches, there's no point in
adding unused attributes :-)

> The respective arguments are optional on tx and included on rx.
> Therefore unaware existing software is not affected.

This may be true, but doesn't *new* hostapd have to know that this is
supported, or otherwise fall back to sending the frames as data frames?

Seems to me a (driver) capability for this is needed.

johannes

Re: [PATCH 2/2] nl80211: use src and dst addr attribute for control port tx/rx

[Markus Theil]

On 1/15/20 12:30 PM, Johannes Berg wrote:
> Hi Markus,
>
> First, I think you should squash these two patches, there's no point in
> adding unused attributes :-)
Ok.
>> The respective arguments are optional on tx and included on rx.
>> Therefore unaware existing software is not affected.
> This may be true, but doesn't *new* hostapd have to know that this is
> supported, or otherwise fall back to sending the frames as data frames?
>
> Seems to me a (driver) capability for this is needed.
Sounds good and would make a clean detection in hostapd possible.
I'll update my patch.

Markus
> johannes
>