sockets: remove dom_externalize

It was used only by unix(4) and now is completely isolated.

sys/kern/uipc_debug.c

@@ -236,9 +236,6 @@ db_print_domain(struct domain *d, const char *domain_name, int indent)
 	db_printf("dom_family: %d   ", d->dom_family);
 	db_printf("dom_name: %s\n", d->dom_name);
 
-	db_print_indent(indent);
-	db_printf("dom_externalize: %p   ", d->dom_externalize);
-
 	db_print_indent(indent);
 	db_printf("dom_protosw: %p   ", d->dom_protosw);
 	db_printf("dom_next: %p\n", d->dom_next.sle_next);

sys/kern/uipc_socket.c

@@ -2934,13 +2934,7 @@ soreceive_generic_locked(struct socket *so, struct sockaddr **psa,
 		while (cm != NULL) {
 			cmn = cm->m_next;
 			cm->m_next = NULL;
-			if (pr->pr_domain->dom_externalize != NULL) {
-				SOCKBUF_UNLOCK(&so->so_rcv);
-				VNET_SO_ASSERT(so);
-				error = (*pr->pr_domain->dom_externalize)
-				    (cm, controlp, flags);
-				SOCKBUF_LOCK(&so->so_rcv);
-			} else if (controlp != NULL)
+			if (controlp != NULL)
 				*controlp = cm;
 			else
 				m_freem(cm);
@@ -3623,10 +3617,7 @@ soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio,
 		while (cm != NULL) {
 			cmn = cm->m_next;
 			cm->m_next = NULL;
-			if (pr->pr_domain->dom_externalize != NULL) {
-				error = (*pr->pr_domain->dom_externalize)
-				    (cm, controlp, flags);
-			} else if (controlp != NULL)
+			if (controlp != NULL)
 				*controlp = cm;
 			else
 				m_freem(cm);

sys/kern/uipc_usrreq.c

@@ -4422,7 +4422,6 @@ static struct protosw seqpacketproto = {
 static struct domain localdomain = {
 	.dom_family =		AF_LOCAL,
 	.dom_name =		"local",
-	.dom_externalize =	unp_externalize,
 	.dom_nprotosw =		3,
 	.dom_protosw =		{
 		&streamproto,

sys/sys/domain.h

@@ -52,8 +52,6 @@ struct domain {
 	char	*dom_name;
 	int	dom_flags;
 	int	(*dom_probe)(void);	/* check for support (optional) */
-	int	(*dom_externalize)	/* externalize access rights */
-		(struct mbuf *, struct mbuf **, int);
 	struct rib_head *(*dom_rtattach)	/* initialize routing table */
 		(uint32_t);
 	void	(*dom_rtdetach)		/* clean up routing table */