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>

1 files changed, 1 insertions, 0 deletions

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