There is a consensus that ifaddr.ifa_addr should never be NULL,

except in places dealing with ifaddr creation or destruction; and
in such special places incomplete ifaddrs should never be linked
to system-wide data structures.  Therefore we can eliminate all the
superfluous checks for "ifa->ifa_addr != NULL" and get ready
to the system crashing honestly instead of masking possible bugs.

Suggested by:	glebius, jhb, ru

11 files changed, 28 insertions, 50 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index f92c930..d540c95 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -581,12 +581,11 @@ if_purgeaddrs(struct ifnet *ifp)
 	struct ifaddr *ifa, *next;
 
 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
-
-		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_LINK)
+		if (ifa->ifa_addr->sa_family == AF_LINK)
 			continue;
 #ifdef INET
 		/* XXX: Ugly!! ad hoc just for INET */
-		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
+		if (ifa->ifa_addr->sa_family == AF_INET) {
 			struct ifaliasreq ifr;
 
 			bzero(&ifr, sizeof(ifr));
@@ -599,7 +598,7 @@ if_purgeaddrs(struct ifnet *ifp)
 		}
 #endif /* INET */
 #ifdef INET6
-		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6) {
+		if (ifa->ifa_addr->sa_family == AF_INET6) {
 			in6_purgeaddr(ifa);
 			/* ifp_addrhead is already updated */
 			continue;
@@ -2404,8 +2403,7 @@ if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
 		 * the address change.
 		 */
 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
-			if (ifa->ifa_addr != NULL &&
-			    ifa->ifa_addr->sa_family == AF_INET)
+			if (ifa->ifa_addr->sa_family == AF_INET)
 				arp_ifinit(ifp, ifa);
 		}
 #endif
diff --git a/sys/net/if_atmsubr.c b/sys/net/if_atmsubr.c
index 00f89d0..d3f7956 100644
--- a/sys/net/if_atmsubr.c
+++ b/sys/net/if_atmsubr.c
@@ -387,8 +387,8 @@ atm_ifattach(struct ifnet *ifp)
 #elif defined(__FreeBSD__) || defined(__bsdi__)
 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) 
 #endif
-		if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
-		    sdl->sdl_family == AF_LINK) {
+		if (ifa->ifa_addr->sa_family == AF_LINK) {
+			sdl = (struct sockaddr_dl *)ifa->ifa_addr;
 			sdl->sdl_type = IFT_ATM;
 			sdl->sdl_alen = ifp->if_addrlen;
 #ifdef notyet /* if using ATMARP, store hardware address using the next line */
diff --git a/sys/net/if_stf.c b/sys/net/if_stf.c
index 23f51cc..594b648 100644
--- a/sys/net/if_stf.c
+++ b/sys/net/if_stf.c
@@ -368,8 +368,6 @@ stf_getsrcifa6(ifp)
 	struct in_addr in;
 
 	TAILQ_FOREACH(ia, &ifp->if_addrlist, ifa_list) {
-		if (ia->ifa_addr == NULL)
-			continue;
 		if (ia->ifa_addr->sa_family != AF_INET6)
 			continue;
 		sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index deee367..b0d0e42 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -393,28 +393,23 @@ tuninit(struct ifnet *ifp)
 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
 	getmicrotime(&ifp->if_lastchange);
 
-	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
-		if (ifa->ifa_addr == NULL)
-			error = EFAULT;
-			/* XXX: Should maybe return straight off? */
-		else {
 #ifdef INET
-			if (ifa->ifa_addr->sa_family == AF_INET) {
-			    struct sockaddr_in *si;
-
-			    si = (struct sockaddr_in *)ifa->ifa_addr;
-			    mtx_lock(&tp->tun_mtx);
-			    if (si->sin_addr.s_addr)
-				    tp->tun_flags |= TUN_IASET;
-
-			    si = (struct sockaddr_in *)ifa->ifa_dstaddr;
-			    if (si && si->sin_addr.s_addr)
-				    tp->tun_flags |= TUN_DSTADDR;
-			    mtx_unlock(&tp->tun_mtx);
-			}
-#endif
+	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
+		if (ifa->ifa_addr->sa_family == AF_INET) {
+			struct sockaddr_in *si;
+
+			si = (struct sockaddr_in *)ifa->ifa_addr;
+			mtx_lock(&tp->tun_mtx);
+			if (si->sin_addr.s_addr)
+				tp->tun_flags |= TUN_IASET;
+
+			si = (struct sockaddr_in *)ifa->ifa_dstaddr;
+			if (si && si->sin_addr.s_addr)
+				tp->tun_flags |= TUN_DSTADDR;
+			mtx_unlock(&tp->tun_mtx);
 		}
 	}
+#endif
 	return (error);
 }
 
diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index 1b154df..94beb78 100644
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -654,7 +654,7 @@ in_arpinput(m)
 	 * as a dummy address for the rest of the function.
 	 */
 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
-		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
+		if (ifa->ifa_addr->sa_family == AF_INET) {
 			ia = ifatoia(ifa);
 			goto match;
 		}
diff --git a/sys/netinet/ip_divert.c b/sys/netinet/ip_divert.c
index 2b14f44..7136644 100644
--- a/sys/netinet/ip_divert.c
+++ b/sys/netinet/ip_divert.c
@@ -206,8 +206,6 @@ divert_packet(struct mbuf *m, int incoming)
 
 		/* Find IP address for receive interface */
 		TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
-			if (ifa->ifa_addr == NULL)
-				continue;
 			if (ifa->ifa_addr->sa_family != AF_INET)
 				continue;
 			divsrc.sin_addr =
diff --git a/sys/netinet/ip_fw2.c b/sys/netinet/ip_fw2.c
index 5ad1eb6..64cfeeb 100644
--- a/sys/netinet/ip_fw2.c
+++ b/sys/netinet/ip_fw2.c
@@ -465,8 +465,6 @@ iface_match(struct ifnet *ifp, ipfw_insn_if *cmd)
 
 		/* XXX lock? */
 		TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
-			if (ia->ifa_addr == NULL)
-				continue;
 			if (ia->ifa_addr->sa_family != AF_INET)
 				continue;
 			if (cmd->p.ip.s_addr == ((struct sockaddr_in *)
@@ -575,8 +573,6 @@ search_ip6_addr_net (struct in6_addr * ip6_addr)
 
 	TAILQ_FOREACH(mdc, &ifnet, if_link)
 		TAILQ_FOREACH(mdc2, &mdc->if_addrlist, ifa_list) {
-			if (!mdc2->ifa_addr)
-				continue;
 			if (mdc2->ifa_addr->sa_family == AF_INET6) {
 				fdm = (struct in6_ifaddr *)mdc2;
 				copia = fdm->ia_addr.sin6_addr;
diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index fcc3080..5c05d6a 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -1696,8 +1696,6 @@ in6_ifinit(ifp, ia, sin6, newhost)
 	 * and to validate the address if necessary.
 	 */
 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
-		if (ifa->ifa_addr == NULL)
-			continue;	/* just for safety */
 		if (ifa->ifa_addr->sa_family != AF_INET6)
 			continue;
 		ifacount++;
@@ -1830,8 +1828,6 @@ in6ifa_ifpforlinklocal(ifp, ignoreflags)
 	struct ifaddr *ifa;
 
 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
-		if (ifa->ifa_addr == NULL)
-			continue;	/* just for safety */
 		if (ifa->ifa_addr->sa_family != AF_INET6)
 			continue;
 		if (IN6_IS_ADDR_LINKLOCAL(IFA_IN6(ifa))) {
@@ -1857,8 +1853,6 @@ in6ifa_ifpwithaddr(ifp, addr)
 	struct ifaddr *ifa;
 
 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
-		if (ifa->ifa_addr == NULL)
-			continue;	/* just for safety */
 		if (ifa->ifa_addr->sa_family != AF_INET6)
 			continue;
 		if (IN6_ARE_ADDR_EQUAL(addr, IFA_IN6(ifa)))
diff --git a/sys/netinet6/in6_var.h b/sys/netinet6/in6_var.h
index 4d3c6ba..faa3e62 100644
--- a/sys/netinet6/in6_var.h
+++ b/sys/netinet6/in6_var.h
@@ -494,8 +494,6 @@ MALLOC_DECLARE(M_IP6MADDR);
 do {									\
 	struct ifaddr *ifa;						\
 	TAILQ_FOREACH(ifa, &(ifp)->if_addrlist, ifa_list) {		\
-		if (!ifa->ifa_addr)					\
-			continue;					\
 		if (ifa->ifa_addr->sa_family == AF_INET6)		\
 			break;						\
 	}								\
diff --git a/sys/nfsclient/bootp_subr.c b/sys/nfsclient/bootp_subr.c
index 1b4eded..dfd2395 100644
--- a/sys/nfsclient/bootp_subr.c
+++ b/sys/nfsclient/bootp_subr.c
@@ -1048,10 +1048,11 @@ bootpc_fakeup_interface(struct bootpc_ifcontext *ifctx,
 
 	sdl = NULL;
 	TAILQ_FOREACH(ifa, &ifctx->ifp->if_addrhead, ifa_link)
-		if (ifa->ifa_addr->sa_family == AF_LINK &&
-		    (sdl = ((struct sockaddr_dl *) ifa->ifa_addr)) != NULL &&
-		    sdl->sdl_type == IFT_ETHER)
-			break;
+		if (ifa->ifa_addr->sa_family == AF_LINK) {
+			sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+			if (sdl->sdl_type == IFT_ETHER)
+				break;
+		}
 
 	if (sdl == NULL)
 		panic("bootpc: Unable to find HW address for %s",
diff --git a/sys/nfsclient/nfs_diskless.c b/sys/nfsclient/nfs_diskless.c
index 9aa2de1..bc62b50 100644
--- a/sys/nfsclient/nfs_diskless.c
+++ b/sys/nfsclient/nfs_diskless.c
@@ -132,8 +132,8 @@ nfs_setup_diskless(void)
 	IFNET_RLOCK();
 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
-			if ((ifa->ifa_addr->sa_family == AF_LINK) &&
-			    (sdl = ((struct sockaddr_dl *)ifa->ifa_addr))) {
+			if (ifa->ifa_addr->sa_family == AF_LINK) {
+				sdl = (struct sockaddr_dl *)ifa->ifa_addr;
 				if ((sdl->sdl_type == ourdl.sdl_type) &&
 				    (sdl->sdl_alen == ourdl.sdl_alen) &&
 				    !bcmp(LLADDR(sdl),