net: implement a SO_PROTOCOL getsockoption

Similar to SO_TYPE returning the socket type, SO_PROTOCOL allows to
retrieve the protocol used with a given socket.

I am not quite sure why we have that-many copies of socket.h, and why
the values are not the same on all arches either, but for where hex
numbers dominate, I use 0x1029 for SO_PROTOCOL as that seems to be
the next free unused number across a bunch of operating systems, or
so Google results make me want to believe. SO_PROTOCOL for others
just uses the next free Linux number, 38.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

20 files changed, 40 insertions, 0 deletions

diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h
index 3641ec1452f4..2f8b4d377749 100644
--- a/arch/alpha/include/asm/socket.h
+++ b/arch/alpha/include/asm/socket.h
@@ -32,6 +32,7 @@
 #define	SO_RCVTIMEO	0x1012
 #define	SO_SNDTIMEO	0x1013
 #define SO_ACCEPTCONN	0x1014
+#define SO_PROTOCOL	0x1028
 
 /* linux-specific, might as well be the same as on i386 */
 #define SO_NO_CHECK	11
diff --git a/arch/arm/include/asm/socket.h b/arch/arm/include/asm/socket.h
index 537de4e0ef50..7f47454ffbf3 100644
--- a/arch/arm/include/asm/socket.h
+++ b/arch/arm/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/avr32/include/asm/socket.h b/arch/avr32/include/asm/socket.h
index 04c860619700..6af2866a4f00 100644
--- a/arch/avr32/include/asm/socket.h
+++ b/arch/avr32/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/asm/socket.h b/arch/cris/include/asm/socket.h
index d5cf74005408..f3859fb0990c 100644
--- a/arch/cris/include/asm/socket.h
+++ b/arch/cris/include/asm/socket.h
@@ -59,6 +59,8 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/asm/socket.h b/arch/frv/include/asm/socket.h
index 57c3d4054e8b..8dab3486ffa4 100644
--- a/arch/frv/include/asm/socket.h
+++ b/arch/frv/include/asm/socket.h
@@ -57,5 +57,7 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/h8300/include/asm/socket.h b/arch/h8300/include/asm/socket.h
index 602518a70a1a..ba770d09cd63 100644
--- a/arch/h8300/include/asm/socket.h
+++ b/arch/h8300/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/ia64/include/asm/socket.h b/arch/ia64/include/asm/socket.h
index 745421225ec6..091cd9d47d0f 100644
--- a/arch/ia64/include/asm/socket.h
+++ b/arch/ia64/include/asm/socket.h
@@ -66,4 +66,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h
index be7ed589af5c..d36f5928fb79 100644
--- a/arch/m32r/include/asm/socket.h
+++ b/arch/m32r/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/m68k/include/asm/socket.h b/arch/m68k/include/asm/socket.h
index ca87f938b03f..060cb7ed024f 100644
--- a/arch/m68k/include/asm/socket.h
+++ b/arch/m68k/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/microblaze/include/asm/socket.h b/arch/microblaze/include/asm/socket.h
index 825936860314..96bf8bfa935e 100644
--- a/arch/microblaze/include/asm/socket.h
+++ b/arch/microblaze/include/asm/socket.h
@@ -66,4 +66,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_MICROBLAZE_SOCKET_H */
diff --git a/arch/mips/include/asm/socket.h b/arch/mips/include/asm/socket.h
index 2abca1780169..289ce5f5f2a3 100644
--- a/arch/mips/include/asm/socket.h
+++ b/arch/mips/include/asm/socket.h
@@ -42,6 +42,7 @@ To add: #define SO_REUSEPORT 0x0200	/* Allow local address and port reuse.  */
 #define SO_SNDTIMEO	0x1005	/* send timeout */
 #define SO_RCVTIMEO 	0x1006	/* receive timeout */
 #define SO_ACCEPTCONN	0x1009
+#define SO_PROTOCOL	0x1028	/* protocol type */
 
 /* linux-specific, might as well be the same as on i386 */
 #define SO_NO_CHECK	11
diff --git a/arch/mn10300/include/asm/socket.h b/arch/mn10300/include/asm/socket.h
index fb5daf438ec9..19d7cf709b77 100644
--- a/arch/mn10300/include/asm/socket.h
+++ b/arch/mn10300/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/asm/socket.h b/arch/parisc/include/asm/socket.h
index 885472bf7b78..a658b09df624 100644
--- a/arch/parisc/include/asm/socket.h
+++ b/arch/parisc/include/asm/socket.h
@@ -24,6 +24,7 @@
 #define SO_RCVTIMEO	0x1006
 #define SO_ERROR	0x1007
 #define SO_TYPE		0x1008
+#define SO_PROTOCOL	0x1028
 #define SO_PEERNAME	0x2000
 
 #define SO_NO_CHECK	0x400b
diff --git a/arch/powerpc/include/asm/socket.h b/arch/powerpc/include/asm/socket.h
index 1e5cfad0e3f7..609049d7117e 100644
--- a/arch/powerpc/include/asm/socket.h
+++ b/arch/powerpc/include/asm/socket.h
@@ -64,4 +64,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/asm/socket.h b/arch/s390/include/asm/socket.h
index 02330c50241b..65baa9a83abc 100644
--- a/arch/s390/include/asm/socket.h
+++ b/arch/s390/include/asm/socket.h
@@ -65,4 +65,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/asm/socket.h b/arch/sparc/include/asm/socket.h
index 982a12f959f4..9cbbfafd0538 100644
--- a/arch/sparc/include/asm/socket.h
+++ b/arch/sparc/include/asm/socket.h
@@ -29,6 +29,8 @@
 #define SO_RCVBUFFORCE	0x100b
 #define SO_ERROR	0x1007
 #define SO_TYPE		0x1008
+#define SO_PROTOCOL	0x1028
+
 
 /* Linux specific, keep the same. */
 #define SO_NO_CHECK	0x000b
diff --git a/arch/x86/include/asm/socket.h b/arch/x86/include/asm/socket.h
index ca8bf2cd0ba9..1077d2535a32 100644
--- a/arch/x86/include/asm/socket.h
+++ b/arch/x86/include/asm/socket.h
@@ -57,4 +57,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* _ASM_X86_SOCKET_H */
diff --git a/arch/xtensa/include/asm/socket.h b/arch/xtensa/include/asm/socket.h
index dd1a7a4a1cea..e47f172142f1 100644
--- a/arch/xtensa/include/asm/socket.h
+++ b/arch/xtensa/include/asm/socket.h
@@ -68,4 +68,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/asm-generic/socket.h b/include/asm-generic/socket.h
index 5d79e409241c..7e24d186616e 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -60,4 +60,6 @@
 #define SO_TIMESTAMPING		37
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
+#define SO_PROTOCOL		38
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index a324a80c163e..ebce661234ac 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -482,6 +482,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		sk->sk_reuse = valbool;
 		break;
 	case SO_TYPE:
+	case SO_PROTOCOL:
 	case SO_ERROR:
 		ret = -ENOPROTOOPT;
 		break;
@@ -764,6 +765,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sk->sk_type;
 		break;
 
+	case SO_PROTOCOL:
+		v.val = sk->sk_protocol;
+		break;
+
 	case SO_ERROR:
 		v.val = -sock_error(sk);
 		if (v.val == 0)