Introduce a new sysctl NET_RT_IFNAMES that returns only ifnames to ifindex

mappings. This will be used by if_nameindex(3), if_nametoindex(3) and
if_indextoname(3) soon to fix the issues in pledge because of inet6 link
local addressing.
OK mpi@ benno@ deraadt@
The libc version will follow soon so better start updating your kernels

2 files changed, 42 insertions, 3 deletions

diff --git a/sys/net/if.h b/sys/net/if.h
index 82dd41cc06e..760892939c1 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.h,v 1.170 2015/10/23 01:19:04 dlg Exp $	*/
+/*	$OpenBSD: if.h,v 1.171 2015/10/23 10:22:29 claudio Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -304,6 +304,12 @@ struct if_announcemsghdr {
 #define IFAN_ARRIVAL	0	/* interface arrival */
 #define IFAN_DEPARTURE	1	/* interface departure */
 
+/* message format used to pass interface name to index mappings */
+struct if_nameindex_msg {
+	unsigned int	if_index;
+	char		if_name[IFNAMSIZ];
+};
+
 /*
  * interface groups
  */
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 4f7d6261fac..12d963e4dec 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtsock.c,v 1.173 2015/10/22 17:19:38 mpi Exp $	*/
+/*	$OpenBSD: rtsock.c,v 1.174 2015/10/23 10:22:29 claudio Exp $	*/
 /*	$NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $	*/
 
 /*
@@ -102,6 +102,9 @@ int		 rt_msg2(int, int, struct rt_addrinfo *, caddr_t,
 		     struct walkarg *);
 void		 rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
 
+int		 sysctl_iflist(int, struct walkarg *);
+int		 sysctl_ifnames(struct walkarg *);
+
 struct routecb {
 	struct rawcb	rcb;
 	struct timeout	timeout;
@@ -1321,6 +1324,34 @@ sysctl_iflist(int af, struct walkarg *w)
 }
 
 int
+sysctl_ifnames(struct walkarg *w)
+{
+	struct if_nameindex_msg ifn;
+	struct ifnet *ifp;
+	int error = 0;
+
+	/* XXX ignore tableid for now */
+	TAILQ_FOREACH(ifp, &ifnet, if_list) {
+		if (w->w_arg && w->w_arg != ifp->if_index)
+			continue;
+		w->w_needed += sizeof(ifn);
+		if (w->w_where && w->w_needed <= 0) {
+
+			memset(&ifn, 0, sizeof(ifn));
+			ifn.if_index = ifp->if_index;
+			strlcpy(ifn.if_name, ifp->if_xname,
+			    sizeof(ifn.if_name));
+			error = copyout(&ifn, w->w_where, sizeof(ifn));
+			if (error)
+				return (error);
+			w->w_where += sizeof(ifn);
+		}
+	}
+
+	return (0);
+}
+
+int
 sysctl_rtable(int *name, u_int namelen, void *where, size_t *given, void *new,
     size_t newlen)
 {
@@ -1351,7 +1382,6 @@ sysctl_rtable(int *name, u_int namelen, void *where, size_t *given, void *new,
 
 	s = splsoftnet();
 	switch (w.w_op) {
-
 	case NET_RT_DUMP:
 	case NET_RT_FLAGS:
 		for (i = 1; i <= AF_MAX; i++) {
@@ -1387,6 +1417,9 @@ sysctl_rtable(int *name, u_int namelen, void *where, size_t *given, void *new,
 		    &tableinfo, sizeof(tableinfo));
 		splx(s);
 		return (error);
+	case NET_RT_IFNAMES:
+		error = sysctl_ifnames(&w);
+		break;
 	}
 	splx(s);
 	free(w.w_tmem, M_RTABLE, 0);