implement SO_DOMAIN and SO_PROTOCOL so that the domain and the protocol

can also be retrieved with getsockopt(3)
it looks like these will also be in the next issue of posix:
http://austingroupbugs.net/view.php?id=840#c2263

ok claudio@, sthen@

lib/libc/sys/getsockopt.2

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: getsockopt.2,v 1.55 2019/02/13 11:55:21 martijn Exp $
+.\"	$OpenBSD: getsockopt.2,v 1.56 2019/07/22 15:34:07 robert Exp $
 .\"	$NetBSD: getsockopt.2,v 1.7 1995/02/27 12:33:29 cgd Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)getsockopt.2	8.3 (Berkeley) 4/19/94
 .\"
-.Dd $Mdocdate: February 13 2019 $
+.Dd $Mdocdate: July 22 2019 $
 .Dt GETSOCKOPT 2
 .Os
 .Sh NAME
@@ -174,6 +174,10 @@ clear all memory containing user supplied data
 get the type of the socket (get only)
 .It Dv SO_ERROR
 get and clear error on the socket (get only)
+.It Dv SO_DOMAIN
+get the domain of the socket (get only)
+.It Dv SO_PROTOCOL
+get the protocol of the socket (get only)
 .El
 .Pp
 .Dv SO_DEBUG
@@ -451,7 +455,9 @@ If
 is set, overwrite kernel memory after sending data.
 .Pp
 Finally,
-.Dv SO_TYPE
+.Dv SO_TYPE ,
+.Dv SO_DOMAIN ,
+.Dv SO_PROTOCOL
 and
 .Dv SO_ERROR
 are options used only with
@@ -460,6 +466,12 @@ are options used only with
 returns the type of the socket, such as
 .Dv SOCK_STREAM ;
 it is useful for servers that inherit sockets on startup.
+.Dv SO_DOMAIN
+returns the domain of the socket, such as
+.Dv AF_INET .
+.Dv SO_PROTOCOL
+returns the protocol of the socket such as
+.Dv IPPROTO_TCP .
 .Dv SO_ERROR
 returns any pending error on the socket and clears the error status.
 It may be used to check for asynchronous errors on connected

sys/kern/uipc_socket.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket.c,v 1.233 2019/07/11 11:57:35 bluhm Exp $	*/
+/*	$OpenBSD: uipc_socket.c,v 1.234 2019/07/22 15:34:07 robert Exp $	*/
 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
 
 /*
@@ -1868,6 +1868,14 @@ sogetopt(struct socket *so, int level, int optname, struct mbuf *m)
 			so->so_error = 0;
 			break;
 
+		case SO_DOMAIN:
+			*mtod(m, int *) = so->so_proto->pr_domain->dom_family;
+			break;
+
+		case SO_PROTOCOL:
+			*mtod(m, int *) = so->so_proto->pr_protocol;
+			break;
+
 		case SO_SNDBUF:
 			*mtod(m, int *) = so->so_snd.sb_hiwat;
 			break;

sys/sys/socket.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: socket.h,v 1.97 2019/07/03 10:08:10 dlg Exp $	*/
+/*	$OpenBSD: socket.h,v 1.98 2019/07/22 15:34:07 robert Exp $	*/
 /*	$NetBSD: socket.h,v 1.14 1996/02/09 18:25:36 christos Exp $	*/
 
 /*
@@ -113,6 +113,8 @@ typedef	__sa_family_t	sa_family_t;	/* sockaddr address family type */
 #define	SO_RTABLE	0x1021		/* routing table to be used */
 #define	SO_PEERCRED	0x1022		/* get connect-time credentials */
 #define	SO_SPLICE	0x1023		/* splice data to other socket */
+#define	SO_DOMAIN	0x1024		/* get socket domain */
+#define	SO_PROTOCOL	0x1025		/* get socket protocol */
 
 /*
  * Structure used for manipulating linger option.