rtnetlink: add NEWCACHEREPORT message type

New NEWCACHEREPORT message type to be used for cache reports sent
via Netlink, effectively allowing splitting cache report reception from
mroute programming.

Suggested-by: Ryan Halbrook <[e-mail]>
Signed-off-by: Julien Gomes <[e-mail]>
Reviewed-by: Nikolay Aleksandrov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/rtnetlink.h

···
 	RTM_GETSTATS = 94,
 #define RTM_GETSTATS RTM_GETSTATS
 
+	RTM_NEWCACHEREPORT = 96,
+#define RTM_NEWCACHEREPORT RTM_NEWCACHEREPORT
+
 	__RTM_MAX,
 #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
 };

security/selinux/nlmsgtab.c

···
 	{ RTM_GETNSID,		NETLINK_ROUTE_SOCKET__NLMSG_READ  },
 	{ RTM_NEWSTATS,		NETLINK_ROUTE_SOCKET__NLMSG_READ },
 	{ RTM_GETSTATS,		NETLINK_ROUTE_SOCKET__NLMSG_READ  },
+	{ RTM_NEWCACHEREPORT,	NETLINK_ROUTE_SOCKET__NLMSG_READ },
 };
 
 static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
···
 	switch (sclass) {
 	case SECCLASS_NETLINK_ROUTE_SOCKET:
 		/* RTM_MAX always point to RTM_SETxxxx, ie RTM_NEWxxx + 3 */
-		BUILD_BUG_ON(RTM_MAX != (RTM_NEWSTATS + 3));
+		BUILD_BUG_ON(RTM_MAX != (RTM_NEWCACHEREPORT + 3));
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
 				 sizeof(nlmsg_route_perms));
 		break;