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>
diff --git a/include/asm-generic/socket.h b/include/asm-generic/socket.h
index 5d79e40..7e24d18 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 */