Introduce if_get() to retrieve an interface descriptor pointer given

an interface index and replace all the redondant checks and accesses
to a global array by a call to this function.

With imputs from and ok bluhm@, mikeb@

2 files changed, 21 insertions, 10 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 7b240389444..6d6f5cc70fb 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.251 2013/03/15 20:45:34 tedu Exp $	*/
+/*	$OpenBSD: if.c,v 1.252 2013/03/20 10:34:12 mpi Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -190,8 +190,8 @@ ifinit()
 	if_slowtimo(&if_slowtim);
 }
 
-static int if_index = 0;
-int if_indexlim = 0;
+static unsigned int if_index = 0;
+static unsigned int if_indexlim = 0;
 struct ifaddr **ifnet_addrs = NULL;
 struct ifnet **ifindex2ifnet = NULL;
 struct ifnet_head ifnet = TAILQ_HEAD_INITIALIZER(ifnet);
@@ -932,8 +932,7 @@ ifa_ifwithnet(struct sockaddr *addr, u_int rdomain)
 	rdomain = rtable_l2(rdomain);
 	if (af == AF_LINK) {
 		struct sockaddr_dl *sdl = (struct sockaddr_dl *)addr;
-		if (sdl->sdl_index && sdl->sdl_index < if_indexlim &&
-		    ifindex2ifnet[sdl->sdl_index])
+		if (sdl->sdl_index && if_get(sdl->sdl_index))
 			return (ifnet_addrs[sdl->sdl_index]);
 	}
 	TAILQ_FOREACH(ifp, &ifnet, if_list) {
@@ -1164,8 +1163,7 @@ if_slowtimo(void *arg)
 }
 
 /*
- * Map interface name to
- * interface structure pointer.
+ * Map interface name to interface structure pointer.
  */
 struct ifnet *
 ifunit(const char *name)
@@ -1180,6 +1178,20 @@ ifunit(const char *name)
 }
 
 /*
+ * Map interface index to interface structure pointer.
+ */
+struct ifnet *
+if_get(unsigned int index)
+{
+	struct ifnet *ifp = NULL;
+
+	if (index < if_indexlim)
+		ifp = ifindex2ifnet[index];
+
+	return (ifp);
+}
+
+/*
  * Interface ioctls.
  */
 int
diff --git a/sys/net/if.h b/sys/net/if.h
index 5c3d4d1251a..f496059d9d9 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.h,v 1.139 2013/03/07 09:40:19 mpi Exp $	*/
+/*	$OpenBSD: if.h,v 1.140 2013/03/20 10:34:12 mpi Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -798,9 +798,7 @@ do {									\
 
 extern int ifqmaxlen;
 extern struct ifnet_head ifnet;
-extern struct ifnet **ifindex2ifnet;
 extern struct ifnet *lo0ifp;
-extern int if_indexlim;
 
 #define	ether_input_mbuf(ifp, m)        ether_input((ifp), NULL, (m))
 
@@ -833,6 +831,7 @@ int	if_addgroup(struct ifnet *, const char *);
 int	if_delgroup(struct ifnet *, const char *);
 void	if_group_routechange(struct sockaddr *, struct sockaddr *);
 struct	ifnet *ifunit(const char *);
+struct	ifnet *if_get(unsigned int);
 void	if_start(struct ifnet *);
 void	ifnewlladdr(struct ifnet *);