diff --git a/usr.sbin/route6d/route6d.c b/usr.sbin/route6d/route6d.c
index ee577eb0fe59..a08d7cbec937 100644
--- a/usr.sbin/route6d/route6d.c
+++ b/usr.sbin/route6d/route6d.c
@@ -686,9 +686,9 @@ static int nrt;
 static struct netinfo6 *np;
 
 void
-ripflush(ifcp, sin)
+ripflush(ifcp, sin6)
 	struct ifc *ifcp;
-	struct sockaddr_in6 *sin;
+	struct sockaddr_in6 *sin6;
 {
 	int i;
 	int error;
@@ -696,10 +696,10 @@ ripflush(ifcp, sin)
 	if (ifcp)
 		tracet(1, "Send(%s): info(%d) to %s.%d\n",
 			ifcp->ifc_name, nrt,
-			inet6_n2p(&sin->sin6_addr), ntohs(sin->sin6_port));
+			inet6_n2p(&sin6->sin6_addr), ntohs(sin6->sin6_port));
 	else
 		tracet(1, "Send: info(%d) to %s.%d\n",
-			nrt, inet6_n2p(&sin->sin6_addr), ntohs(sin->sin6_port));
+			nrt, inet6_n2p(&sin6->sin6_addr), ntohs(sin6->sin6_port));
 	if (dflag >= 2) {
 		np = ripbuf->rip6_nets;
 		for (i = 0; i < nrt; i++, np++) {
@@ -722,7 +722,7 @@ ripflush(ifcp, sin)
 			trace(2, "\n");
 		}
 	}
-	error = sendpacket(sin, RIPSIZE(nrt));
+	error = sendpacket(sin6, RIPSIZE(nrt));
 	if (error == EAFNOSUPPORT) {
 		/* Protocol not supported */
 		tracet(1, "Could not send info to %s (%s): "
@@ -737,9 +737,9 @@ ripflush(ifcp, sin)
  * Generate RIP6_RESPONSE packets and send them.
  */
 void
-ripsend(ifcp, sin, flag)
+ripsend(ifcp, sin6, flag)
 	struct	ifc *ifcp;
-	struct	sockaddr_in6 *sin;
+	struct	sockaddr_in6 *sin6;
 	int flag;
 {
 	struct	riprt *rrt;
@@ -763,12 +763,12 @@ ripsend(ifcp, sin, flag)
 			*np = rrt->rrt_info;
 			np++; nrt++;
 			if (nrt == maxrte) {
-				ripflush(NULL, sin);
+				ripflush(NULL, sin6);
 				nh = NULL;
 			}
 		}
 		if (nrt)	/* Send last packet */
-			ripflush(NULL, sin);
+			ripflush(NULL, sin6);
 		return;
 	}
 
@@ -792,7 +792,7 @@ ripsend(ifcp, sin, flag)
 		np = ripbuf->rip6_nets;
 		*np = rrt_info;
 		nrt = 1;
-		ripflush(ifcp, sin);
+		ripflush(ifcp, sin6);
 		return;
 	}
 
@@ -825,7 +825,7 @@ ripsend(ifcp, sin, flag)
 		    (rrt->rrt_rflags & RRTF_NH_NOT_LLADDR) == 0) {
 			if (nh == NULL || !IN6_ARE_ADDR_EQUAL(nh, &rrt->rrt_gw)) {
 				if (nrt == maxrte - 2)
-					ripflush(ifcp, sin);
+					ripflush(ifcp, sin6);
 				np->rip6_dest = rrt->rrt_gw;
 				if (IN6_IS_ADDR_LINKLOCAL(&np->rip6_dest))
 					SET_IN6_LINKLOCAL_IFINDEX(np->rip6_dest, 0);
@@ -840,7 +840,7 @@ ripsend(ifcp, sin, flag)
 				  rrt->rrt_rflags & RRTF_NH_NOT_LLADDR)) {
 			/* Reset nexthop */
 			if (nrt == maxrte - 2)
-				ripflush(ifcp, sin);
+				ripflush(ifcp, sin6);
 			memset(np, 0, sizeof(struct netinfo6));
 			np->rip6_metric = NEXTHOP_METRIC;
 			nh = NULL;
@@ -851,12 +851,12 @@ ripsend(ifcp, sin, flag)
 		*np = rrt->rrt_info;
 		np++; nrt++;
 		if (nrt == maxrte) {
-			ripflush(ifcp, sin);
+			ripflush(ifcp, sin6);
 			nh = NULL;
 		}
 	}
 	if (nrt)	/* Send last packet */
-		ripflush(ifcp, sin);
+		ripflush(ifcp, sin6);
 }
 
 /*
@@ -963,8 +963,8 @@ tobeadv(rrt, ifcp)
  * Send a rip packet actually.
  */
 int
-sendpacket(sin, len)
-	struct	sockaddr_in6 *sin;
+sendpacket(sin6, len)
+	struct	sockaddr_in6 *sin6;
 	int	len;
 {
 	/*
@@ -981,18 +981,18 @@ sendpacket(sin, len)
 	struct sockaddr_in6 sincopy;
 
 	/* do not overwrite the given sin */
-	sincopy = *sin;
-	sin = &sincopy;
+	sincopy = *sin6;
+	sin6 = &sincopy;
 
-	if (IN6_IS_ADDR_LINKLOCAL(&sin->sin6_addr)
-	 || IN6_IS_ADDR_MULTICAST(&sin->sin6_addr)) {
-		idx = IN6_LINKLOCAL_IFINDEX(sin->sin6_addr);
-		SET_IN6_LINKLOCAL_IFINDEX(sin->sin6_addr, 0);
+	if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)
+	 || IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
+		idx = IN6_LINKLOCAL_IFINDEX(sin6->sin6_addr);
+		SET_IN6_LINKLOCAL_IFINDEX(sin6->sin6_addr, 0);
 	} else
 		idx = 0;
 
-	m.msg_name = (caddr_t)sin;
-	m.msg_namelen = sizeof(*sin);
+	m.msg_name = (caddr_t)sin6;
+	m.msg_namelen = sizeof(*sin6);
 	iov[0].iov_base = (caddr_t)ripbuf;
 	iov[0].iov_len = len;
 	m.msg_iov = iov;
@@ -1339,11 +1339,11 @@ sendrequest(ifcp)
  * Process a RIP6_REQUEST packet.
  */
 void
-riprequest(ifcp, np, nn, sin)
+riprequest(ifcp, np, nn, sin6)
 	struct ifc *ifcp;
 	struct netinfo6 *np;
 	int nn;
-	struct sockaddr_in6 *sin;
+	struct sockaddr_in6 *sin6;
 {
 	int i;
 	struct riprt *rrt;
@@ -1359,12 +1359,12 @@ riprequest(ifcp, np, nn, sin)
 			else
 				np->rip6_metric = HOPCNT_INFINITY6;
 		}
-		(void)sendpacket(sin, RIPSIZE(nn));
+		(void)sendpacket(sin6, RIPSIZE(nn));
 		return;
 	}
 	/* Whole routing table dump */
 	trace(1, "\tRIP Request -- whole routing table\n");
-	ripsend(ifcp, sin, RRTF_SENDANYWAY);
+	ripsend(ifcp, sin6, RRTF_SENDANYWAY);
 }
 
 /*
@@ -1450,20 +1450,20 @@ ifconfig1(name, sa, ifcp, s)
 	int	s;
 {
 	struct	in6_ifreq ifr;
-	const struct sockaddr_in6 *sin;
+	const struct sockaddr_in6 *sin6;
 	struct	ifac *ifa;
 	int	plen;
 	char	buf[BUFSIZ];
 
-	sin = (const struct sockaddr_in6 *)sa;
-	ifr.ifr_addr = *sin;
+	sin6 = (const struct sockaddr_in6 *)sa;
+	ifr.ifr_addr = *sin6;
 	strcpy(ifr.ifr_name, name);
 	if (ioctl(s, SIOCGIFNETMASK_IN6, (char *)&ifr) < 0) {
 		fatal("ioctl: SIOCGIFNETMASK_IN6");
 		/*NOTREACHED*/
 	}
 	plen = sin6mask2len(&ifr.ifr_addr);
-	if ((ifa = ifa_match(ifcp, &sin->sin6_addr, plen)) != NULL) {
+	if ((ifa = ifa_match(ifcp, &sin6->sin6_addr, plen)) != NULL) {
 		/* same interface found */
 		/* need check if something changed */
 		/* XXX not yet implemented */
@@ -1480,10 +1480,10 @@ ifconfig1(name, sa, ifcp, s)
 	ifa->ifa_conf = ifcp;
 	ifa->ifa_next = ifcp->ifc_addr;
 	ifcp->ifc_addr = ifa;
-	ifa->ifa_addr = sin->sin6_addr;
+	ifa->ifa_addr = sin6->sin6_addr;
 	ifa->ifa_plen = plen;
 	if (ifcp->ifc_flags & IFF_POINTOPOINT) {
-		ifr.ifr_addr = *sin;
+		ifr.ifr_addr = *sin6;
 		if (ioctl(s, SIOCGIFDSTADDR_IN6, (char *)&ifr) < 0) {
 			fatal("ioctl: SIOCGIFDSTADDR_IN6");
 			/*NOTREACHED*/
@@ -2651,7 +2651,7 @@ addroute(rrt, gw, ifcp)
 	struct	netinfo6 *np;
 	u_char	buf[BUFSIZ], buf1[BUFSIZ], buf2[BUFSIZ];
 	struct	rt_msghdr	*rtm;
-	struct	sockaddr_in6	*sin;
+	struct	sockaddr_in6	*sin6;
 	int	len;
 
 	np = &rrt->rrt_info;
@@ -2677,24 +2677,24 @@ addroute(rrt, gw, ifcp)
 	rtm->rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
 	rtm->rtm_rmx.rmx_hopcount = np->rip6_metric - 1;
 	rtm->rtm_inits = RTV_HOPCOUNT;
-	sin = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
+	sin6 = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
 	/* Destination */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = np->rip6_dest;
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = np->rip6_dest;
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 	/* Gateway */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = *gw;
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = *gw;
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 	/* Netmask */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = *(plen2mask(np->rip6_plen));
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = *(plen2mask(np->rip6_plen));
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 
-	len = (char *)sin - (char *)buf;
+	len = (char *)sin6 - (char *)buf;
 	rtm->rtm_msglen = len;
 	if (write(rtsock, buf, len) > 0)
 		return 0;
@@ -2722,7 +2722,7 @@ delroute(np, gw)
 {
 	u_char	buf[BUFSIZ], buf2[BUFSIZ];
 	struct	rt_msghdr	*rtm;
-	struct	sockaddr_in6	*sin;
+	struct	sockaddr_in6	*sin6;
 	int	len;
 
 	inet_ntop(AF_INET6, (void *)gw, (char *)buf2, sizeof(buf2));
@@ -2744,24 +2744,24 @@ delroute(np, gw)
 	if (np->rip6_plen == sizeof(struct in6_addr) * 8)
 		rtm->rtm_flags |= RTF_HOST;
 	rtm->rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
-	sin = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
+	sin6 = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
 	/* Destination */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = np->rip6_dest;
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = np->rip6_dest;
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 	/* Gateway */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = *gw;
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = *gw;
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 	/* Netmask */
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = *(plen2mask(np->rip6_plen));
-	sin = (struct sockaddr_in6 *)((char *)sin + ROUNDUP(sin->sin6_len));
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = *(plen2mask(np->rip6_plen));
+	sin6 = (struct sockaddr_in6 *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
 
-	len = (char *)sin - (char *)buf;
+	len = (char *)sin6 - (char *)buf;
 	rtm->rtm_msglen = len;
 	if (write(rtsock, buf, len) >= 0)
 		return 0;
@@ -2791,7 +2791,7 @@ getroute(np, gw)
 	u_long myseq;
 	int len;
 	struct rt_msghdr *rtm;
-	struct sockaddr_in6 *sin;
+	struct sockaddr_in6 *sin6;
 
 	rtm = (struct rt_msghdr *)buf;
 	len = sizeof(struct rt_msghdr) + sizeof(struct sockaddr_in6);
@@ -2802,10 +2802,10 @@ getroute(np, gw)
 	rtm->rtm_seq = myseq;
 	rtm->rtm_addrs = RTA_DST;
 	rtm->rtm_msglen = len;
-	sin = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
-	sin->sin6_len = sizeof(struct sockaddr_in6);
-	sin->sin6_family = AF_INET6;
-	sin->sin6_addr = np->rip6_dest;
+	sin6 = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
+	sin6->sin6_len = sizeof(struct sockaddr_in6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_addr = np->rip6_dest;
 	if (write(rtsock, buf, len) < 0) {
 		if (errno == ESRCH)	/* No such route found */
 			return NULL;
@@ -2819,13 +2819,13 @@ getroute(np, gw)
 		}
 		rtm = (struct rt_msghdr *)buf;
 	} while (rtm->rtm_seq != myseq || rtm->rtm_pid != pid);
-	sin = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
+	sin6 = (struct sockaddr_in6 *)&buf[sizeof(struct rt_msghdr)];
 	if (rtm->rtm_addrs & RTA_DST) {
-		sin = (struct sockaddr_in6 *)
-			((char *)sin + ROUNDUP(sin->sin6_len));
+		sin6 = (struct sockaddr_in6 *)
+			((char *)sin6 + ROUNDUP(sin6->sin6_len));
 	}
 	if (rtm->rtm_addrs & RTA_GATEWAY) {
-		*gw = sin->sin6_addr;
+		*gw = sin6->sin6_addr;
 		return gw;
 	}
 	return NULL;