net: add wireless TX status socket option

The 802.1X EAPOL handshake hostapd does requires
knowing whether the frame was ack'ed by the peer.
Currently, we fudge this pretty badly by not even
transmitting the frame as a normal data frame but
injecting it with radiotap and getting the status
out of radiotap monitor as well. This is rather
complex, confuses users (mon.wlan0 presence) and
doesn't work with all hardware.

To get rid of that hack, introduce a real wifi TX
status option for data frame transmissions.

This works similar to the existing TX timestamping
in that it reflects the SKB back to the socket's
error queue with a SCM_WIFI_STATUS cmsg that has
an int indicating ACK status (0/1).

Since it is possible that at some point we will
want to have TX timestamping and wifi status in a
single errqueue SKB (there's little point in not
doing that), redefine SO_EE_ORIGIN_TIMESTAMPING
to SO_EE_ORIGIN_TXSTATUS which can collect more
than just the timestamp; keep the old constant
as an alias of course. Currently the internal APIs
don't make that possible, but it wouldn't be hard
to split them up in a way that makes it possible.

Thanks to Neil Horman for helping me figure out
the functions that add the control messages.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

23 files changed, 123 insertions, 3 deletions

diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h
index 06edfefc337..082355f159e 100644
--- a/arch/alpha/include/asm/socket.h
+++ b/arch/alpha/include/asm/socket.h
@@ -69,6 +69,9 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
  */
diff --git a/arch/arm/include/asm/socket.h b/arch/arm/include/asm/socket.h
index 90ffd04b8e7..dec6f9afb3c 100644
--- a/arch/arm/include/asm/socket.h
+++ b/arch/arm/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/avr32/include/asm/socket.h b/arch/avr32/include/asm/socket.h
index c8d1fae4947..247b88c760b 100644
--- a/arch/avr32/include/asm/socket.h
+++ b/arch/avr32/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/asm/socket.h b/arch/cris/include/asm/socket.h
index 1a4a61909ca..e269264df7c 100644
--- a/arch/cris/include/asm/socket.h
+++ b/arch/cris/include/asm/socket.h
@@ -64,6 +64,9 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/asm/socket.h b/arch/frv/include/asm/socket.h
index a6b26880c1e..ce80fdadcce 100644
--- a/arch/frv/include/asm/socket.h
+++ b/arch/frv/include/asm/socket.h
@@ -62,5 +62,8 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/h8300/include/asm/socket.h b/arch/h8300/include/asm/socket.h
index 04c0f4596eb..cf1daab6f27 100644
--- a/arch/h8300/include/asm/socket.h
+++ b/arch/h8300/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/ia64/include/asm/socket.h b/arch/ia64/include/asm/socket.h
index 51427eaa51b..4b03664e3fb 100644
--- a/arch/ia64/include/asm/socket.h
+++ b/arch/ia64/include/asm/socket.h
@@ -71,4 +71,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h
index 469787c3009..e8b8c5bb053 100644
--- a/arch/m32r/include/asm/socket.h
+++ b/arch/m32r/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/m68k/include/asm/socket.h b/arch/m68k/include/asm/socket.h
index 9bf49c87d95..d4708ce466e 100644
--- a/arch/m68k/include/asm/socket.h
+++ b/arch/m68k/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/mips/include/asm/socket.h b/arch/mips/include/asm/socket.h
index 9de5190f248..ad5c0a7a02a 100644
--- a/arch/mips/include/asm/socket.h
+++ b/arch/mips/include/asm/socket.h
@@ -82,6 +82,9 @@ To add: #define SO_REUSEPORT 0x0200	/* Allow local address and port reuse.  */
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #ifdef __KERNEL__
 
 /** sock_type - Socket types
diff --git a/arch/mn10300/include/asm/socket.h b/arch/mn10300/include/asm/socket.h
index 4e60c428128..876356d7852 100644
--- a/arch/mn10300/include/asm/socket.h
+++ b/arch/mn10300/include/asm/socket.h
@@ -62,4 +62,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/asm/socket.h b/arch/parisc/include/asm/socket.h
index 225b7d6a1a0..d28c51b6106 100644
--- a/arch/parisc/include/asm/socket.h
+++ b/arch/parisc/include/asm/socket.h
@@ -61,6 +61,9 @@
 
 #define SO_RXQ_OVFL             0x4021
 
+#define SO_WIFI_STATUS		0x4022
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
  */
diff --git a/arch/powerpc/include/asm/socket.h b/arch/powerpc/include/asm/socket.h
index 866f7606da6..2fc2af8fbf5 100644
--- a/arch/powerpc/include/asm/socket.h
+++ b/arch/powerpc/include/asm/socket.h
@@ -69,4 +69,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/asm/socket.h b/arch/s390/include/asm/socket.h
index fdff1e995c7..67b5c1b14b5 100644
--- a/arch/s390/include/asm/socket.h
+++ b/arch/s390/include/asm/socket.h
@@ -70,4 +70,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/asm/socket.h b/arch/sparc/include/asm/socket.h
index 9d3fefcff2f..8af1b64168b 100644
--- a/arch/sparc/include/asm/socket.h
+++ b/arch/sparc/include/asm/socket.h
@@ -58,6 +58,9 @@
 
 #define SO_RXQ_OVFL             0x0024
 
+#define SO_WIFI_STATUS		0x0025
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/asm/socket.h b/arch/xtensa/include/asm/socket.h
index cbdf2ffaacf..bb06968be22 100644
--- a/arch/xtensa/include/asm/socket.h
+++ b/arch/xtensa/include/asm/socket.h
@@ -73,4 +73,7 @@
 
 #define SO_RXQ_OVFL             40
 
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS		SO_WIFI_STATUS
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/asm-generic/socket.h b/include/asm-generic/socket.h
index 9a6115e7cf6..49c1704173e 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -64,4 +64,7 @@
 #define SO_DOMAIN		39
 
 #define SO_RXQ_OVFL             40
+
+#define SO_WIFI_STATUS		41
+#define SCM_WIFI_STATUS	SO_WIFI_STATUS
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/include/linux/errqueue.h b/include/linux/errqueue.h
index 034072cea85..c9f522bd17e 100644
--- a/include/linux/errqueue.h
+++ b/include/linux/errqueue.h
@@ -17,7 +17,8 @@ struct sock_extended_err {
 #define SO_EE_ORIGIN_LOCAL	1
 #define SO_EE_ORIGIN_ICMP	2
 #define SO_EE_ORIGIN_ICMP6	3
-#define SO_EE_ORIGIN_TIMESTAMPING 4
+#define SO_EE_ORIGIN_TXSTATUS	4
+#define SO_EE_ORIGIN_TIMESTAMPING SO_EE_ORIGIN_TXSTATUS
 
 #define SO_EE_OFFENDER(ee)	((struct sockaddr*)((ee)+1))
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6a6b352326d..ff7e1306a2d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -218,6 +218,9 @@ enum {
 
 	/* device driver supports TX zero-copy buffers */
 	SKBTX_DEV_ZEROCOPY = 1 << 4,
+
+	/* generate wifi status information (where possible) */
+	SKBTX_WIFI_STATUS = 1 << 5,
 };
 
 /*
@@ -352,6 +355,8 @@ typedef unsigned char *sk_buff_data_t;
  *	@ooo_okay: allow the mapping of a socket to a queue to be changed
  *	@l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
  *		ports.
+ *	@wifi_acked_valid: wifi_acked was set
+ *	@wifi_acked: whether frame was acked on wifi or not
  *	@dma_cookie: a cookie to one of several possible DMA operations
  *		done by skb DMA functions
  *	@secmark: security marking
@@ -445,10 +450,11 @@ struct sk_buff {
 #endif
 	__u8			ooo_okay:1;
 	__u8			l4_rxhash:1;
+	__u8			wifi_acked_valid:1;
+	__u8			wifi_acked:1;
+	/* 10/12 bit hole (depending on ndisc_nodetype presence) */
 	kmemcheck_bitfield_end(flags2);
 
-	/* 0/13 bit hole */
-
 #ifdef CONFIG_NET_DMA
 	dma_cookie_t		dma_cookie;
 #endif
@@ -2263,6 +2269,15 @@ static inline void skb_tx_timestamp(struct sk_buff *skb)
 	sw_tx_timestamp(skb);
 }
 
+/**
+ * skb_complete_wifi_ack - deliver skb with wifi status
+ *
+ * @skb: the original outgoing packet
+ * @acked: ack status
+ *
+ */
+void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
+
 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
 
diff --git a/include/net/sock.h b/include/net/sock.h
index 5ac682f73d6..fa6f5381c5d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -564,6 +564,7 @@ enum sock_flags {
 	SOCK_FASYNC, /* fasync() active */
 	SOCK_RXQ_OVFL,
 	SOCK_ZEROCOPY, /* buffers from userspace */
+	SOCK_WIFI_STATUS, /* push wifi status to userspace */
 };
 
 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
@@ -1714,6 +1715,8 @@ static inline int sock_intr_errno(long timeo)
 
 extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 	struct sk_buff *skb);
+extern void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
+	struct sk_buff *skb);
 
 static __inline__ void
 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
@@ -1741,6 +1744,9 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 		__sock_recv_timestamp(msg, sk, skb);
 	else
 		sk->sk_stamp = kt;
+
+	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
+		__sock_recv_wifi_status(msg, sk, skb);
 }
 
 extern void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ca4db40e75b..2f6babd5a57 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3168,6 +3168,26 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
 }
 EXPORT_SYMBOL_GPL(skb_tstamp_tx);
 
+void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
+{
+	struct sock *sk = skb->sk;
+	struct sock_exterr_skb *serr;
+	int err;
+
+	skb->wifi_acked_valid = 1;
+	skb->wifi_acked = acked;
+
+	serr = SKB_EXT_ERR(skb);
+	memset(serr, 0, sizeof(*serr));
+	serr->ee.ee_errno = ENOMSG;
+	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
+
+	err = sock_queue_err_skb(sk, skb);
+	if (err)
+		kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
+
 
 /**
  * skb_partial_csum_set - set up and verify partial csum values for packet
diff --git a/net/core/sock.c b/net/core/sock.c
index 4ed7b1d12f5..cbdf51c0d5a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -740,6 +740,11 @@ set_rcvbuf:
 	case SO_RXQ_OVFL:
 		sock_valbool_flag(sk, SOCK_RXQ_OVFL, valbool);
 		break;
+
+	case SO_WIFI_STATUS:
+		sock_valbool_flag(sk, SOCK_WIFI_STATUS, valbool);
+		break;
+
 	default:
 		ret = -ENOPROTOOPT;
 		break;
@@ -961,6 +966,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = !!sock_flag(sk, SOCK_RXQ_OVFL);
 		break;
 
+	case SO_WIFI_STATUS:
+		v.val = !!sock_flag(sk, SOCK_WIFI_STATUS);
+		break;
+
 	default:
 		return -ENOPROTOOPT;
 	}
diff --git a/net/socket.c b/net/socket.c
index 2877647f347..425ef427046 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -538,6 +538,8 @@ int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
 		*tx_flags |= SKBTX_HW_TSTAMP;
 	if (sock_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE))
 		*tx_flags |= SKBTX_SW_TSTAMP;
+	if (sock_flag(sk, SOCK_WIFI_STATUS))
+		*tx_flags |= SKBTX_WIFI_STATUS;
 	return 0;
 }
 EXPORT_SYMBOL(sock_tx_timestamp);
@@ -674,6 +676,22 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 }
 EXPORT_SYMBOL_GPL(__sock_recv_timestamp);
 
+void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
+	struct sk_buff *skb)
+{
+	int ack;
+
+	if (!sock_flag(sk, SOCK_WIFI_STATUS))
+		return;
+	if (!skb->wifi_acked_valid)
+		return;
+
+	ack = skb->wifi_acked;
+
+	put_cmsg(msg, SOL_SOCKET, SCM_WIFI_STATUS, sizeof(ack), &ack);
+}
+EXPORT_SYMBOL_GPL(__sock_recv_wifi_status);
+
 static inline void sock_recv_drops(struct msghdr *msg, struct sock *sk,
 				   struct sk_buff *skb)
 {