Invert the signature logic of in{,6}_selectsrc, make them return the

error code and pass the resulting source address back to the caller
through a pointer, as suggested by chrisz.  This gives us more readable
code, and eases the deletion of useless checks in the callers' error path.
Add a bunch of "0 -> NULL" conversions, while here.
ok chrisz@ mpi@

1 files changed, 49 insertions, 51 deletions

diff --git a/sys/netinet6/in6_src.c b/sys/netinet6/in6_src.c
index 7ca882e4ab2..513aef2a245 100644
--- a/sys/netinet6/in6_src.c
+++ b/sys/netinet6/in6_src.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_src.c,v 1.41 2014/04/07 10:04:17 mpi Exp $	*/
+/*	$OpenBSD: in6_src.c,v 1.42 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 itojun Exp $	*/
 
 /*
@@ -96,18 +96,18 @@ int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *,
  * If necessary, this function lookups the routing table and returns
  * an entry to the caller for later use.
  */
-struct in6_addr *
-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)
+int
+in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
+    struct ip6_pktopts *opts, struct ip6_moptions *mopts,
+    struct route_in6 *ro, struct in6_addr *laddr, u_int rtableid)
 {
 	struct ifnet *ifp = NULL;
 	struct in6_addr *dst;
 	struct in6_ifaddr *ia6 = NULL;
 	struct in6_pktinfo *pi = NULL;
+	int	error;
 
 	dst = &dstsock->sin6_addr;
-	*errorp = 0;
 
 	/*
 	 * If the source address is explicitly specified by the caller,
@@ -120,9 +120,9 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 		struct sockaddr_in6 sa6;
 
 		/* get the outgoing interface */
-		if ((*errorp = in6_selectif(dstsock, opts, mopts, ro,
-		    &ifp, rtableid)) != 0)
-			return (NULL);
+		error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid);
+		if (error)
+			return (error);
 
 		bzero(&sa6, sizeof(sa6));
 		sa6.sin6_family = AF_INET6;
@@ -134,22 +134,23 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 
 		ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid));
 		if (ia6 == NULL ||
-		    (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) {
-			*errorp = EADDRNOTAVAIL;
-			return (NULL);
-		}
+		    (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY)))
+			return (EADDRNOTAVAIL);
 
 		pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */
 
-		return (&pi->ipi6_addr);
+		*in6src = &pi->ipi6_addr;
+		return (0);
 	}
 
 	/*
 	 * If the source address is not specified but the socket(if any)
 	 * is already bound, use the bound address.
 	 */
-	if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
-		return (laddr);
+	if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
+		*in6src = laddr;
+		return (0);
+	}
 
 	/*
 	 * If the caller doesn't specify the source address but
@@ -158,16 +159,15 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 	 */
 	if (pi && pi->ipi6_ifindex) {
 		ifp = if_get(pi->ipi6_ifindex);
-		if (ifp == NULL) {
-			*errorp = ENXIO; /* XXX: better error? */
-			return (0);
-		}
+		if (ifp == NULL)
+			return (ENXIO); /* XXX: better error? */
+
 		ia6 = in6_ifawithscope(ifp, dst, rtableid);
-		if (ia6 == 0) {
-			*errorp = EADDRNOTAVAIL;
-			return (0);
-		}
-		return (&ia6->ia_addr.sin6_addr);
+		if (ia6 == NULL)
+			return (EADDRNOTAVAIL);
+
+		*in6src = &ia6->ia_addr.sin6_addr;
+		return (0);
 	}
 
 	/*
@@ -182,16 +182,15 @@ 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) {
 		ifp = if_get(dstsock->sin6_scope_id);
-		if (ifp == NULL) {
-			*errorp = ENXIO; /* XXX: better error? */
-			return (0);
-		}
+		if (ifp == NULL)
+			return (ENXIO); /* XXX: better error? */
+
 		ia6 = in6_ifawithscope(ifp, dst, rtableid);
-		if (ia6 == 0) {
-			*errorp = EADDRNOTAVAIL;
-			return (0);
-		}
-		return (&ia6->ia_addr.sin6_addr);
+		if (ia6 == NULL)
+			return (EADDRNOTAVAIL);
+
+		*in6src = &ia6->ia_addr.sin6_addr;
+		return (0);
 	}
 
 	/*
@@ -209,11 +208,11 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 
 		if (ifp) {
 			ia6 = in6_ifawithscope(ifp, dst, rtableid);
-			if (ia6 == 0) {
-				*errorp = EADDRNOTAVAIL;
-				return (0);
-			}
-			return (&ia6->ia_addr.sin6_addr);
+			if (ia6 == NULL)
+				return (EADDRNOTAVAIL);
+
+			*in6src = &ia6->ia_addr.sin6_addr;
+			return (0);
 		}
 	}
 
@@ -236,11 +235,11 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 				if (ia6 == 0)
 					ia6 = ifatoia6(rt->rt_ifa);
 			}
-			if (ia6 == 0) {
-				*errorp = EADDRNOTAVAIL;
-				return (0);
-			}
-			return (&ia6->ia_addr.sin6_addr);
+			if (ia6 == NULL)
+				return (EADDRNOTAVAIL);
+
+			*in6src = &ia6->ia_addr.sin6_addr;
+			return (0);
 		}
 	}
 
@@ -286,15 +285,14 @@ in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
 			if (ia6 == 0) /* xxx scope error ?*/
 				ia6 = ifatoia6(ro->ro_rt->rt_ifa);
 		}
-		if (ia6 == 0) {
-			*errorp = EHOSTUNREACH;	/* no route */
-			return (0);
-		}
-		return (&ia6->ia_addr.sin6_addr);
+		if (ia6 == NULL)
+			return (EHOSTUNREACH);	/* no route */
+
+		*in6src = &ia6->ia_addr.sin6_addr;
+		return (0);
 	}
 
-	*errorp = EADDRNOTAVAIL;
-	return (0);
+	return (EADDRNOTAVAIL);
 }
 
 int