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@

7 files changed, 84 insertions, 95 deletions

diff --git a/sys/netinet6/icmp6.c b/sys/netinet6/icmp6.c
index 3d8a0f6ba78..a5b1f852738 100644
--- a/sys/netinet6/icmp6.c
+++ b/sys/netinet6/icmp6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: icmp6.c,v 1.142 2014/04/14 09:06:42 mpi Exp $	*/
+/*	$OpenBSD: icmp6.c,v 1.143 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: icmp6.c,v 1.217 2001/06/20 15:03:29 jinmei Exp $	*/
 
 /*
@@ -1962,7 +1962,7 @@ icmp6_reflect(struct mbuf *m, size_t off)
 	struct ip6_hdr *ip6;
 	struct icmp6_hdr *icmp6;
 	struct in6_ifaddr *ia6;
-	struct in6_addr t, *src = 0;
+	struct in6_addr t, *src = NULL;
 	int plen;
 	int type, code;
 	struct ifnet *outif = NULL;
@@ -2060,8 +2060,8 @@ icmp6_reflect(struct mbuf *m, size_t off)
 		src = &t;
 	}
 
-	if (src == 0) {
-		int e;
+	if (src == NULL) {
+		int error;
 		struct route_in6 ro;
 		char addr[INET6_ADDRSTRLEN];
 
@@ -2071,18 +2071,18 @@ icmp6_reflect(struct mbuf *m, size_t off)
 		 * source address of the erroneous packet.
 		 */
 		bzero(&ro, sizeof(ro));
-		src = in6_selectsrc(&sa6_src, NULL, NULL, &ro, NULL, &e,
+		error = in6_selectsrc(&src, &sa6_src, NULL, NULL, &ro, NULL,
 		    m->m_pkthdr.ph_rtableid);
 		if (ro.ro_rt) { /* XXX: see comments in icmp6_mtudisc_update */
 			RTFREE(ro.ro_rt); /* XXX: we could use this */
 		}
-		if (src == NULL) {
+		if (error) {
 			nd6log((LOG_DEBUG,
 			    "icmp6_reflect: source can't be determined: "
 			    "dst=%s, error=%d\n",
 			    inet_ntop(AF_INET6, &sa6_src.sin6_addr,
 				addr, sizeof(addr)),
-			    e));
+			    error));
 			goto bad;
 		}
 	}
diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
index 28e37dd3d0e..c3fd4790b76 100644
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_pcb.c,v 1.61 2014/04/16 13:04:38 mpi Exp $	*/
+/*	$OpenBSD: in6_pcb.c,v 1.62 2014/04/18 10:48:30 jca Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -429,14 +429,11 @@ in6_pcbconnect(struct inpcb *inp, struct mbuf *nam)
 	 * with the address specified by setsockopt(IPV6_PKTINFO).
 	 * Is it the intended behavior?
 	 */
-	in6a = in6_selectsrc(sin6, inp->inp_outputopts6,
+	error = in6_selectsrc(&in6a, sin6, inp->inp_outputopts6,
 	    inp->inp_moptions6, &inp->inp_route6, &inp->inp_laddr6,
-	    &error, inp->inp_rtableid);
-	if (in6a == 0) {
-		if (error == 0)
-			error = EADDRNOTAVAIL;
+	    inp->inp_rtableid);
+	if (error)
 		return (error);
-	}
 
 	if (inp->inp_route6.ro_rt && inp->inp_route6.ro_rt->rt_flags & RTF_UP)
 		ifp = inp->inp_route6.ro_rt->rt_ifp;
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
diff --git a/sys/netinet6/ip6_var.h b/sys/netinet6/ip6_var.h
index 04d43031e48..c78c161852e 100644
--- a/sys/netinet6/ip6_var.h
+++ b/sys/netinet6/ip6_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_var.h,v 1.47 2013/10/21 12:27:16 deraadt Exp $	*/
+/*	$OpenBSD: ip6_var.h,v 1.48 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: ip6_var.h,v 1.33 2000/06/11 14:59:20 jinmei Exp $	*/
 
 /*
@@ -308,9 +308,9 @@ int	rip6_sysctl(int *, u_int, void *, size_t *, void *, size_t);
 int	dest6_input(struct mbuf **, int *, int);
 int	none_input(struct mbuf **, int *, int);
 
-struct in6_addr *in6_selectsrc(struct sockaddr_in6 *, struct ip6_pktopts *,
-	    struct ip6_moptions *, struct route_in6 *, struct in6_addr *,
-	    int *, u_int);
+int	in6_selectsrc(struct in6_addr **, struct sockaddr_in6 *,
+	    struct ip6_pktopts *, struct ip6_moptions *, struct route_in6 *,
+	    struct in6_addr *, u_int);
 int	in6_selectroute(struct sockaddr_in6 *, struct ip6_pktopts *,
 	    struct ip6_moptions *, struct route_in6 *, struct ifnet **,
 	    struct rtentry **, u_int rtableid);
diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 52da768dcf2..729c959ea27 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6_nbr.c,v 1.77 2014/04/14 09:06:42 mpi Exp $	*/
+/*	$OpenBSD: nd6_nbr.c,v 1.78 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei Exp $	*/
 
 /*
@@ -456,9 +456,9 @@ nd6_ns_output(struct ifnet *ifp, struct in6_addr *daddr6,
 			int error;
 
 			bcopy(&dst_sa, &ro.ro_dst, sizeof(dst_sa));
-			src0 = in6_selectsrc(&dst_sa, NULL, NULL, &ro, NULL,
-			    &error, m->m_pkthdr.ph_rtableid);
-			if (src0 == NULL) {
+			error = in6_selectsrc(&src0, &dst_sa, NULL, NULL, &ro,
+			    NULL, m->m_pkthdr.ph_rtableid);
+			if (error) {
 				char addr[INET6_ADDRSTRLEN];
 
 				nd6log((LOG_DEBUG,
@@ -968,9 +968,9 @@ nd6_na_output(struct ifnet *ifp, struct in6_addr *daddr6,
 	 * Select a source whose scope is the same as that of the dest.
 	 */
 	bcopy(&dst_sa, &ro.ro_dst, sizeof(dst_sa));
-	src0 = in6_selectsrc(&dst_sa, NULL, NULL, &ro, NULL, &error,
+	error = in6_selectsrc(&src0, &dst_sa, NULL, NULL, &ro, NULL,
 	    m->m_pkthdr.ph_rtableid);
-	if (src0 == NULL) {
+	if (error) {
 		char addr[INET6_ADDRSTRLEN];
 
 		nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c
index 36ccd5afa5b..281ddc77ba9 100644
--- a/sys/netinet6/raw_ip6.c
+++ b/sys/netinet6/raw_ip6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: raw_ip6.c,v 1.65 2014/04/14 09:06:42 mpi Exp $	*/
+/*	$OpenBSD: raw_ip6.c,v 1.66 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: raw_ip6.c,v 1.69 2001/03/04 15:55:44 itojun Exp $	*/
 
 /*
@@ -413,13 +413,12 @@ rip6_output(struct mbuf *m, ...)
 	{
 		struct in6_addr *in6a;
 
-		if ((in6a = in6_selectsrc(dstsock, optp, in6p->inp_moptions6,
-		    &in6p->inp_route6, &in6p->inp_laddr6, &error,
-		    in6p->inp_rtableid)) == 0) {
-			if (error == 0)
-				error = EADDRNOTAVAIL;
+		error = in6_selectsrc(&in6a, dstsock, optp,
+		    in6p->inp_moptions6, &in6p->inp_route6, &in6p->inp_laddr6,
+		    in6p->inp_rtableid);
+		if (error)
 			goto bad;
-		}
+
 		ip6->ip6_src = *in6a;
 		if (in6p->inp_route6.ro_rt &&
 		    in6p->inp_route6.ro_rt->rt_flags & RTF_UP)
@@ -722,14 +721,11 @@ rip6_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam,
 		}
 
 		/* Source address selection. XXX: need pcblookup? */
-		in6a = in6_selectsrc(addr, in6p->inp_outputopts6,
+		error = in6_selectsrc(&in6a, addr, in6p->inp_outputopts6,
 		    in6p->inp_moptions6, &in6p->inp_route6,
-		    &in6p->inp_laddr6, &error, in6p->inp_rtableid);
-		if (in6a == NULL) {
-			if (error == 0)
-				error = EADDRNOTAVAIL;
+		    &in6p->inp_laddr6, in6p->inp_rtableid);
+		if (error)
 			break;
-		}
 		in6p->inp_laddr6 = *in6a;
 		in6p->inp_faddr6 = addr->sin6_addr;
 		soisconnected(so);
diff --git a/sys/netinet6/udp6_output.c b/sys/netinet6/udp6_output.c
index be94e2c500c..4df8e16258e 100644
--- a/sys/netinet6/udp6_output.c
+++ b/sys/netinet6/udp6_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: udp6_output.c,v 1.26 2014/04/16 13:04:38 mpi Exp $	*/
+/*	$OpenBSD: udp6_output.c,v 1.27 2014/04/18 10:48:30 jca Exp $	*/
 /*	$KAME: udp6_output.c,v 1.21 2001/02/07 11:51:54 itojun Exp $	*/
 
 /*
@@ -152,14 +152,12 @@ udp6_output(struct inpcb *in6p, struct mbuf *m, struct mbuf *addr6,
 		}
 
 		/* we don't support IPv4 mapped address */
-		laddr = in6_selectsrc(sin6, optp,
+		error = in6_selectsrc(&laddr, sin6, optp,
 		    in6p->inp_moptions6, &in6p->inp_route6,
-		    &in6p->inp_laddr6, &error, in6p->inp_rtableid);
-		if (laddr == NULL) {
-			if (error == 0)
-				error = EADDRNOTAVAIL;
+		    &in6p->inp_laddr6, in6p->inp_rtableid);
+		if (error)
 			goto release;
-		}
+
 		if (in6p->inp_lport == 0 &&
 		    (error = in6_pcbsetport(laddr, in6p, p)) != 0)
 			goto release;