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>

Conflicts:
	include/asm-generic/socket.h
	net/core/sock.c

Change-Id: I032421709aa9b052fb7dde423c3b976bb80ebe0a
diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h
index 06edfef..082355f 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 3ff6501..d97caad 100644
--- a/arch/arm/include/asm/socket.h
+++ b/arch/arm/include/asm/socket.h
@@ -63,4 +63,7 @@
 #define SO_RXQ_OVFL             40
 #define SO_RXQ_ALLOC		101  /* non-upstreamed sockopt */
 
+#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 c8d1fae..247b88c 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 1a4a619..e269264 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 a6b2688..ce80fda 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 04c0f45..cf1daab 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 51427ea..4b03664 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 469787c3..e8b8c5b 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 9bf49c8..d4708ce 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 9de5190..ad5c0a7 100644
--- a/arch/mips/include/asm/socket.h
+++ b/arch/mips/include/asm/socket.h
@@ -82,6 +82,9 @@
 
 #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 4e60c42..876356d 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 225b7d6..d28c51b 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 866f760..2fc2af8 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 fdff1e9..67b5c1b 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 9d3fefc..8af1b64 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 cbdf2ff..bb06968 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 8e7c2f7..22d4e36d 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -66,4 +66,6 @@
 #define SO_RXQ_OVFL             40
 #define SO_RXQ_ALLOC		101  /* non-upstreamed sockopt */
 
+#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 034072c..c9f522b 100644
--- a/include/linux/errqueue.h
+++ b/include/linux/errqueue.h
@@ -17,7 +17,8 @@
 #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 70fd1e2..e131195 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -218,6 +218,9 @@
 
 	/* 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 @@
  *	@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
@@ -448,10 +453,11 @@
 #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
@@ -2308,6 +2314,15 @@
 	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 80ed0da..bd8102d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -564,6 +564,7 @@
 	SOCK_RXQ_OVFL,
 	SOCK_RXQ_ALLOC,
 	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)
@@ -1717,6 +1718,8 @@
 
 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)
@@ -1744,6 +1747,9 @@
 		__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 9b9be63..e54b3c4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3343,6 +3343,26 @@
 }
 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 2d19e4e..39bde3c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -736,12 +736,18 @@
 	case SO_RXQ_OVFL:
 		sock_valbool_flag(sk, SOCK_RXQ_OVFL, valbool);
 		break;
+
 	case SO_RXQ_ALLOC:
 		if (valbool)
 			sock_set_flag(sk, SOCK_RXQ_ALLOC);
 		else
 			sock_reset_flag(sk, SOCK_RXQ_ALLOC);
 		break;
+
+	case SO_WIFI_STATUS:
+		sock_valbool_flag(sk, SOCK_WIFI_STATUS, valbool);
+		break;
+
 	default:
 		ret = -ENOPROTOOPT;
 		break;
@@ -967,6 +973,10 @@
 		v.val = !!sock_flag(sk, SOCK_RXQ_ALLOC);
 		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 9ba4f71..1eab220 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -538,6 +538,8 @@
 		*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 @@
 }
 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)
 {