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@

3 files changed, 33 insertions, 53 deletions

diff --git a/sys/netinet6/in6_src.c b/sys/netinet6/in6_src.c
index e46678d79b0..3068833ac18 100644
--- a/sys/netinet6/in6_src.c
+++ b/sys/netinet6/in6_src.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_src.c,v 1.28 2013/03/04 14:42:25 bluhm Exp $	*/
+/*	$OpenBSD: in6_src.c,v 1.29 2013/03/20 10:34:12 mpi Exp $	*/
 /*	$KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 itojun Exp $	*/
 
 /*
@@ -103,6 +103,7 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
     struct ip6_moptions *mopts, struct route_in6 *ro, struct in6_addr *laddr,
     int *errorp, u_int rtableid)
 {
+	struct ifnet *ifp = NULL;
 	struct in6_addr *dst;
 	struct in6_ifaddr *ia6 = NULL;
 	struct in6_pktinfo *pi = NULL;
@@ -118,7 +119,6 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 	 */
 	if (opts && (pi = opts->ip6po_pktinfo) &&
 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
-		struct ifnet *ifp = NULL;
 		struct sockaddr_in6 sa6;
 
 		/* get the outgoing interface */
@@ -160,9 +160,12 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 	 * the interface.
 	 */
 	if (pi && pi->ipi6_ifindex) {
-		/* XXX boundary check is assumed to be already done. */
-		ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
-				       dst, rtableid);
+		ifp = if_get(pi->ipi6_ifindex);
+		if (ifp == NULL) {
+			*errorp = ENXIO; /* XXX: better error? */
+			return (0);
+		}
+		ia6 = in6_ifawithscope(ifp, dst, rtableid);
 		if (ia6 == 0) {
 			*errorp = EADDRNOTAVAIL;
 			return (0);
@@ -181,18 +184,12 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 	 */
 	if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
 	     IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) {
-		/*
-		 * I'm not sure if boundary check for scope_id is done
-		 * somewhere...
-		 */
-		if (dstsock->sin6_scope_id < 0 ||
-		    if_indexlim <= dstsock->sin6_scope_id ||
-		    !ifindex2ifnet[dstsock->sin6_scope_id]) {
+		ifp = if_get(dstsock->sin6_scope_id);
+		if (ifp == NULL) {
 			*errorp = ENXIO; /* XXX: better error? */
 			return (0);
 		}
-		ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
-				       dst, rtableid);
+		ia6 = in6_ifawithscope(ifp, dst, rtableid);
 		if (ia6 == 0) {
 			*errorp = EADDRNOTAVAIL;
 			return (0);
@@ -208,10 +205,10 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 	 * choose a loopback interface as the outgoing interface.
 	 */
 	if (IN6_IS_ADDR_MULTICAST(dst)) {
-		struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
+		ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
 
 		if (!ifp && dstsock->sin6_scope_id)
-			ifp = ifindex2ifnet[htons(dstsock->sin6_scope_id)];
+			ifp = if_get(htons(dstsock->sin6_scope_id));
 
 		if (ifp) {
 			ia6 = in6_ifawithscope(ifp, dst, rtableid);
@@ -349,8 +346,7 @@ selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 
 	/* If the caller specify the outgoing interface explicitly, use it. */
 	if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
-		/* XXX boundary check is assumed to be already done. */
-		ifp = ifindex2ifnet[pi->ipi6_ifindex];
+		ifp = if_get(pi->ipi6_ifindex);
 		if (ifp != NULL &&
 		    (norouteok || retrt == NULL ||
 		     IN6_IS_ADDR_MULTICAST(dst))) {
@@ -640,7 +636,9 @@ in6_embedscope(in6, sin6, in6p, ifpp)
 		if (in6p && in6p->in6p_outputopts &&
 		    (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
 		    pi->ipi6_ifindex) {
-			ifp = ifindex2ifnet[pi->ipi6_ifindex];
+			ifp = if_get(pi->ipi6_ifindex);
+			if (ifp == NULL)
+				return ENXIO;  /* XXX EINVAL? */
 			in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
 		} else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
 			   in6p->in6p_moptions &&
@@ -648,11 +646,9 @@ in6_embedscope(in6, sin6, in6p, ifpp)
 			ifp = in6p->in6p_moptions->im6o_multicast_ifp;
 			in6->s6_addr16[1] = htons(ifp->if_index);
 		} else if (scopeid) {
-			/* boundary check */
-			if (scopeid < 0 || if_indexlim <= scopeid ||
-			    !ifindex2ifnet[scopeid])
+			ifp = if_get(scopeid);
+			if (ifp == NULL)
 				return ENXIO;  /* XXX EINVAL? */
-			ifp = ifindex2ifnet[scopeid];
 			/*XXX assignment to 16bit from 32bit variable */
 			in6->s6_addr16[1] = htons(scopeid & 0xffff);
 		}
@@ -694,8 +690,7 @@ in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6,
 		scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
 		if (scopeid) {
 			/* sanity check */
-			if (scopeid < 0 || if_indexlim <= scopeid ||
-			    !ifindex2ifnet[scopeid])
+			if (if_get(scopeid) == NULL)
 				return ENXIO;
 			if (ifp && ifp->if_index != scopeid)
 				return ENXIO;
diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
index 762bcff38d5..35f50677523 100644
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -584,9 +584,7 @@ add_m6if(struct mif6ctl *mifcp)
 	mifp = mif6table + mifcp->mif6c_mifi;
 	if (mifp->m6_ifp)
 		return EADDRINUSE; /* XXX: is it appropriate? */
-	if (mifcp->mif6c_pifi == 0 || mifcp->mif6c_pifi >= if_indexlim)
-		return ENXIO;
-	ifp = ifindex2ifnet[mifcp->mif6c_pifi];
+	ifp = if_get(mifcp->mif6c_pifi);
 	if (!ifp)
 		return ENXIO;
 
diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index 5ab27a5b0ef..9ec2f19239d 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_output.c,v 1.134 2013/03/14 11:18:37 mpi Exp $	*/
+/*	$OpenBSD: ip6_output.c,v 1.135 2013/03/20 10:34:12 mpi Exp $	*/
 /*	$KAME: ip6_output.c,v 1.172 2001/03/25 09:55:56 itojun Exp $	*/
 
 /*
@@ -742,9 +742,9 @@ reroute:
 		 */
 		origifp = NULL;
 		if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
-			origifp = ifindex2ifnet[ntohs(ip6->ip6_src.s6_addr16[1])];
+			origifp = if_get(ntohs(ip6->ip6_src.s6_addr16[1]));
 		else if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
-			origifp = ifindex2ifnet[ntohs(ip6->ip6_dst.s6_addr16[1])];
+			origifp = if_get(ntohs(ip6->ip6_dst.s6_addr16[1]));
 		/*
 		 * XXX: origifp can be NULL even in those two cases above.
 		 * For example, if we remove the (only) link-local address
@@ -2380,14 +2380,12 @@ ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
 		if (ifindex == 0)
 			ifp = NULL;
 		else {
-			if (ifindex < 0 || if_indexlim <= ifindex ||
-			    !ifindex2ifnet[ifindex]) {
+			ifp = if_get(ifindex);
+			if (ifp == NULL) {
 				error = ENXIO;	/* XXX EINVAL? */
 				break;
 			}
-			ifp = ifindex2ifnet[ifindex];
-			if (ifp == NULL ||
-			    (ifp->if_flags & IFF_MULTICAST) == 0) {
+			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
 				error = EADDRNOTAVAIL;
 				break;
 			}
@@ -2484,13 +2482,11 @@ ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
 			/*
 			 * If the interface is specified, validate it.
 			 */
-			if (mreq->ipv6mr_interface < 0 ||
-			    if_indexlim <= mreq->ipv6mr_interface ||
-			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
+			ifp = if_get(mreq->ipv6mr_interface);
+			if (ifp == NULL) {
 				error = ENXIO;	/* XXX EINVAL? */
 				break;
 			}
-			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
 		}
 
 		/*
@@ -2558,13 +2554,11 @@ ip6_setmoptions(int optname, struct ip6_moptions **im6op, struct mbuf *m)
 		if (mreq->ipv6mr_interface == 0)
 			ifp = NULL;
 		else {
-			if (mreq->ipv6mr_interface < 0 ||
-			    if_indexlim <= mreq->ipv6mr_interface ||
-			    !ifindex2ifnet[mreq->ipv6mr_interface]) {
+			ifp = if_get(mreq->ipv6mr_interface);
+			if (ifp == NULL) {
 				error = ENXIO;	/* XXX EINVAL? */
 				break;
 			}
-			ifp = ifindex2ifnet[mreq->ipv6mr_interface];
 		}
 
 		/*
@@ -2827,13 +2821,8 @@ ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
 			return (EINVAL);
 		}
 
-		/* validate the interface index if specified. */
-		if (pktinfo->ipi6_ifindex >= if_indexlim ||
-		    pktinfo->ipi6_ifindex < 0) {
-			 return (ENXIO);
-		}
 		if (pktinfo->ipi6_ifindex) {
-			ifp = ifindex2ifnet[pktinfo->ipi6_ifindex];
+			ifp = if_get(pktinfo->ipi6_ifindex);
 			if (ifp == NULL)
 				return (ENXIO);
 		}
@@ -2921,9 +2910,7 @@ ip6_setpktopt(int optname, u_char *buf, int len, struct ip6_pktopts *opt,
 				return (EINVAL);
 			}
 			if (IN6_IS_SCOPE_EMBED(&sa6->sin6_addr)) {
-				if (sa6->sin6_scope_id < 0 ||
-				    if_indexlim <= sa6->sin6_scope_id ||
-				    !ifindex2ifnet[sa6->sin6_scope_id])
+				if (if_get(sa6->sin6_scope_id) == NULL)
 					return (EINVAL);
 				sa6->sin6_addr.s6_addr16[1] =
 				    htonl(sa6->sin6_scope_id);