net: implement a SO_DOMAIN getsockoption

This sockopt goes in line with SO_TYPE and SO_PROTOCOL. It makes it
possible for userspace programs to pass around file descriptors — I
am referring to arguments-to-functions, but it may even work for the
fd passing over UNIX sockets — without needing to also pass the
auxiliary information (PF_INET6/IPPROTO_TCP).

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/include/asm-generic/socket.h b/include/asm-generic/socket.h
index 7e24d186616e..538991cef6f0 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -61,5 +61,6 @@
 #define SCM_TIMESTAMPING        SO_TIMESTAMPING
 
 #define SO_PROTOCOL             38
+#define SO_DOMAIN               39
 
 #endif /* __ASM_GENERIC_SOCKET_H */