[NET]: Introducing socket mark socket option.

A userspace program may wish to set the mark for each packets its send
without using the netfilter MARK target. Changing the mark can be used
for mark based routing without netfilter or for packet filtering.

It requires CAP_NET_ADMIN capability.

Signed-off-by: Laszlo Attila Toth <panther@balabit.hu>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-blackfin/socket.h b/include/asm-blackfin/socket.h
index 5213c96..2ca702e 100644
--- a/include/asm-blackfin/socket.h
+++ b/include/asm-blackfin/socket.h
@@ -50,4 +50,7 @@
 #define SO_PASSSEC		34
 #define SO_TIMESTAMPNS		35
 #define SCM_TIMESTAMPNS		SO_TIMESTAMPNS
+
+#define SO_MARK			36
+
 #endif				/* _ASM_SOCKET_H */