Add a ROUTE_PRIOFILTER socket option for roueing sockets that

allows filtering on the priority of the route. All routes up to
the specified value will be passed.
ok claudio, ok henning previous version, feedback and manpage from
sthen.

2 files changed, 24 insertions, 3 deletions

diff --git a/sys/net/route.h b/sys/net/route.h
index 1ca0a22c45f..9f5459a9a62 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: route.h,v 1.167 2017/08/02 08:38:28 mpi Exp $	*/
+/*	$OpenBSD: route.h,v 1.168 2018/02/11 02:26:55 benno Exp $	*/
 /*	$NetBSD: route.h,v 1.9 1996/02/13 22:00:49 christos Exp $	*/
 
 /*
@@ -297,6 +297,9 @@ struct rt_msghdr {
 				   sent to the client. */
 #define ROUTE_TABLEFILTER 2	/* change routing table the socket is listening
 				   on, RTABLE_ANY listens on all tables. */
+#define ROUTE_PRIOFILTER 3	/* only pass updates with a priority higher or
+				   equal (actual value lower) to the specified
+				   priority. */
 
 #define ROUTE_FILTER(m)	(1 << (m))
 #define RTABLE_ANY	0xffffffff
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 35bdd09d143..70497d29a93 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtsock.c,v 1.260 2018/02/08 22:24:41 claudio Exp $	*/
+/*	$OpenBSD: rtsock.c,v 1.261 2018/02/11 02:26:55 benno Exp $	*/
 /*	$NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $	*/
 
 /*
@@ -141,6 +141,7 @@ struct routecb {
 	unsigned int		msgfilter;
 	unsigned int		flags;
 	u_int			rtableid;
+	u_char			priority;
 };
 #define	sotoroutecb(so)	((struct routecb *)(so)->so_pcb)
 
@@ -308,7 +309,7 @@ route_ctloutput(int op, struct socket *so, int level, int optname,
 {
 	struct routecb *rop = sotoroutecb(so);
 	int error = 0;
-	unsigned int tid;
+	unsigned int tid, prio;
 
 	if (level != AF_ROUTE)
 		return (EINVAL);
@@ -333,6 +334,17 @@ route_ctloutput(int op, struct socket *so, int level, int optname,
 			else
 				rop->rtableid = tid;
 			break;
+		case ROUTE_PRIOFILTER:
+			if (m == NULL || m->m_len != sizeof(unsigned int)) {
+				error = EINVAL;
+				break;
+			}
+			prio = *mtod(m, unsigned int *);
+			if (prio > RTP_MAX)
+				error = EINVAL;
+			else
+				rop->priority = prio;
+			break;
 		default:
 			error = ENOPROTOOPT;
 			break;
@@ -348,6 +360,10 @@ route_ctloutput(int op, struct socket *so, int level, int optname,
 			m->m_len = sizeof(unsigned int);
 			*mtod(m, unsigned int *) = rop->rtableid;
 			break;
+		case ROUTE_PRIOFILTER:
+			m->m_len = sizeof(unsigned int);
+			*mtod(m, unsigned int *) = rop->priority;
+			break;
 		default:
 			error = ENOPROTOOPT;
 			break;
@@ -431,6 +447,8 @@ route_input(struct mbuf *m0, struct socket *so, sa_family_t sa_family)
 		if (rtm->rtm_type != RTM_DESYNC && rop->msgfilter != 0 &&
 		    !(rop->msgfilter & (1 << rtm->rtm_type)))
 			continue;
+		if (rop->priority != 0 && rop->priority < rtm->rtm_priority)
+			continue;
 		switch (rtm->rtm_type) {
 		case RTM_IFANNOUNCE:
 		case RTM_DESYNC: