Ignore Router Advertisment's current hop limit.

Appart from the usual inet6 axe murdering exercise to keep you fit, this
allows us to get rid of a lot of layer violation due to the use of per-
ifp variables to store the current hop limit.

Imputs from bluhm@, ok phessler@, florian@, bluhm@

11 files changed, 28 insertions, 40 deletions

diff --git a/sys/netinet/in_pcb.h b/sys/netinet/in_pcb.h
index 8d351cf6802..9ac0f5bd0fe 100644
--- a/sys/netinet/in_pcb.h
+++ b/sys/netinet/in_pcb.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in_pcb.h,v 1.90 2015/09/22 09:34:39 vgross Exp $	*/
+/*	$OpenBSD: in_pcb.h,v 1.91 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$NetBSD: in_pcb.h,v 1.14 1996/02/13 23:42:00 christos Exp $	*/
 
 /*
@@ -287,7 +287,7 @@ struct rtentry *
 int	in6_pcbnotify(struct inpcbtable *, struct sockaddr_in6 *,
 	u_int, const struct sockaddr_in6 *, u_int, u_int, int, void *,
 	void (*)(struct inpcb *, int));
-int	in6_selecthlim(struct inpcb *, struct ifnet *);
+int	in6_selecthlim(struct inpcb *);
 int	in6_pcbsetport(struct in6_addr *, struct inpcb *, struct proc *);
 #endif /* _KERNEL */
 #endif /* _NETINET_IN_PCB_H_ */
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index f7c98b7f756..a77cc639190 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_input.c,v 1.305 2015/09/11 08:17:06 claudio Exp $	*/
+/*	$OpenBSD: tcp_input.c,v 1.306 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$NetBSD: tcp_input.c,v 1.23 1996/02/13 23:43:44 christos Exp $	*/
 
 /*
@@ -4363,8 +4363,7 @@ syn_cache_respond(struct syn_cache *sc, struct mbuf *m)
 		break;
 #ifdef INET6
 	case AF_INET6:
-		ip6->ip6_hlim = in6_selecthlim(NULL,
-				ro->ro_rt ? ro->ro_rt->rt_ifp : NULL);
+		ip6->ip6_hlim = in6_selecthlim(NULL);
 
 		error = ip6_output(m, NULL /*XXX*/, (struct route_in6 *)ro, 0,
 		    NULL, NULL);
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index aa320da5cd9..7aa2690e21e 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_output.c,v 1.114 2015/09/11 08:17:06 claudio Exp $	*/
+/*	$OpenBSD: tcp_output.c,v 1.115 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$NetBSD: tcp_output.c,v 1.16 1997/06/03 16:17:09 kml Exp $	*/
 
 /*
@@ -1108,7 +1108,7 @@ send:
 				sizeof(struct ip6_hdr);
 			packetlen = m->m_pkthdr.len;
 			ip6->ip6_nxt = IPPROTO_TCP;
-			ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb, NULL);
+			ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb);
 #ifdef TCP_ECN
 			if (needect)
 				ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index 52744c32012..e79fcd2df1c 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_subr.c,v 1.149 2015/10/02 09:51:54 tedu Exp $	*/
+/*	$OpenBSD: tcp_subr.c,v 1.150 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$NetBSD: tcp_subr.c,v 1.22 1996/02/13 23:44:00 christos Exp $	*/
 
 /*
@@ -254,7 +254,7 @@ tcp_template(tp)
 
 			ip6->ip6_nxt = IPPROTO_TCP;
 			ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/
-			ip6->ip6_hlim = in6_selecthlim(inp, NULL);	/*XXX*/
+			ip6->ip6_hlim = in6_selecthlim(inp);	/*XXX*/
 
 			th = (struct tcphdr *)(mtod(m, caddr_t) +
 				sizeof(struct ip6_hdr));
@@ -400,7 +400,7 @@ tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
 	case AF_INET6:
 		ip6->ip6_flow = htonl(0x60000000);
 		ip6->ip6_nxt  = IPPROTO_TCP;
-		ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL);	/*XXX*/
+		ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL);	/*XXX*/
 		ip6->ip6_plen = tlen - sizeof(struct ip6_hdr);
 		ip6->ip6_plen = htons(ip6->ip6_plen);
 		ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL,
diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
index 95ae08f8a90..4e5e1c72e22 100644
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_pcb.c,v 1.81 2015/10/20 18:04:03 deraadt Exp $	*/
+/*	$OpenBSD: in6_pcb.c,v 1.82 2015/10/24 16:08:48 mpi Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -369,7 +369,6 @@ in6_pcbconnect(struct inpcb *inp, struct mbuf *nam)
 {
 	struct in6_addr *in6a = NULL;
 	struct sockaddr_in6 *sin6 = mtod(nam, struct sockaddr_in6 *);
-	struct ifnet *ifp = NULL;	/* outgoing interface */
 	int error = 0;
 	struct sockaddr_in6 tmp;
 
@@ -412,10 +411,7 @@ in6_pcbconnect(struct inpcb *inp, struct mbuf *nam)
 	if (error)
 		return (error);
 
-	if (rtisvalid(inp->inp_route6.ro_rt))
-		ifp = inp->inp_route6.ro_rt->rt_ifp;
-
-	inp->inp_ipv6.ip6_hlim = (u_int8_t)in6_selecthlim(inp, ifp);
+	inp->inp_ipv6.ip6_hlim = (u_int8_t)in6_selecthlim(inp);
 
 	if (in_pcblookup(inp->inp_table, &sin6->sin6_addr, sin6->sin6_port,
 	    IN6_IS_ADDR_UNSPECIFIED(&inp->inp_laddr6) ? in6a : &inp->inp_laddr6,
diff --git a/sys/netinet6/in6_src.c b/sys/netinet6/in6_src.c
index dfe5791948f..045a4e38fb8 100644
--- a/sys/netinet6/in6_src.c
+++ b/sys/netinet6/in6_src.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_src.c,v 1.66 2015/10/24 12:33:16 mpi Exp $	*/
+/*	$OpenBSD: in6_src.c,v 1.67 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 itojun Exp $	*/
 
 /*
@@ -470,14 +470,12 @@ in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
  * 3. The system default hoplimit.
 */
 int
-in6_selecthlim(struct inpcb *in6p, struct ifnet *ifp)
+in6_selecthlim(struct inpcb *in6p)
 {
 	if (in6p && in6p->inp_hops >= 0)
 		return (in6p->inp_hops);
-	else if (ifp)
-		return (ND_IFINFO(ifp)->chlim);
-	else
-		return (ip6_defhlim);
+
+	return (ip6_defhlim);
 }
 
 /*
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 3cb55ede1f2..1d30d63a979 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.c,v 1.158 2015/10/22 16:44:54 mpi Exp $	*/
+/*	$OpenBSD: nd6.c,v 1.159 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: nd6.c,v 1.280 2002/06/08 19:52:07 itojun Exp $	*/
 
 /*
@@ -147,7 +147,6 @@ nd6_ifattach(struct ifnet *ifp)
 
 	nd->initialized = 1;
 
-	nd->chlim = IPV6_DEFHLIM;
 	nd->basereachable = REACHABLE_TIME;
 	nd->reachable = ND_COMPUTE_RTIME(nd->basereachable);
 	nd->retrans = RETRANS_TIMER;
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index f1b3098f590..162dec320a9 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.h,v 1.49 2015/08/31 10:03:47 mpi Exp $	*/
+/*	$OpenBSD: nd6.h,v 1.50 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: nd6.h,v 1.95 2002/06/08 11:31:06 itojun Exp $	*/
 
 /*
@@ -56,7 +56,6 @@ struct nd_ifinfo {
 	u_int32_t retrans;		/* Retrans Timer */
 	u_int32_t flags;		/* Flags */
 	int recalctm;			/* BaseReacable re-calculation timer */
-	u_int8_t chlim;			/* CurHopLimit */
 	u_int8_t initialized; /* Flag to see the entry is initialized */
 	/* the following 3 members are for privacy extension for addrconf */
 	u_int8_t randomseed0[8]; /* upper 64 bits of MD5 digest */
diff --git a/sys/netinet6/nd6_rtr.c b/sys/netinet6/nd6_rtr.c
index 6e85e6c3893..025372d55a6 100644
--- a/sys/netinet6/nd6_rtr.c
+++ b/sys/netinet6/nd6_rtr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6_rtr.c,v 1.126 2015/10/22 15:37:47 bluhm Exp $	*/
+/*	$OpenBSD: nd6_rtr.c,v 1.127 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: nd6_rtr.c,v 1.97 2001/02/07 11:09:13 itojun Exp $	*/
 
 /*
@@ -435,8 +435,12 @@ nd6_ra_input(struct mbuf *m, int off, int icmp6len)
 	}
 	if (nd_ra->nd_ra_retransmit)
 		ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
-	if (nd_ra->nd_ra_curhoplimit)
-		ndi->chlim = nd_ra->nd_ra_curhoplimit;
+	if (nd_ra->nd_ra_curhoplimit) {
+		/*
+		 * Ignore it.  The router doesn't know the diameter of
+		 * the Internet better than this source code.
+		 */
+	}
 	dr = defrtrlist_update(&dr0);
     }
 
diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c
index 9727c64aa6e..75e52bc40b8 100644
--- a/sys/netinet6/raw_ip6.c
+++ b/sys/netinet6/raw_ip6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: raw_ip6.c,v 1.85 2015/10/19 12:11:28 mpi Exp $	*/
+/*	$OpenBSD: raw_ip6.c,v 1.86 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: raw_ip6.c,v 1.69 2001/03/04 15:55:44 itojun Exp $	*/
 
 /*
@@ -344,7 +344,6 @@ rip6_output(struct mbuf *m, ...)
 	u_int	plen = m->m_pkthdr.len;
 	int error = 0;
 	struct ip6_pktopts opt, *optp = NULL, *origoptp;
-	struct ifnet *oifp = NULL;
 	int type, code;		/* for ICMPv6 output statistics only */
 	int priv = 0;
 	va_list ap;
@@ -421,8 +420,6 @@ rip6_output(struct mbuf *m, ...)
 			goto bad;
 
 		ip6->ip6_src = *in6a;
-		if (rtisvalid(in6p->inp_route6.ro_rt))
-			oifp = in6p->inp_route6.ro_rt->rt_ifp;
 	}
 
 	ip6->ip6_flow = in6p->inp_flowinfo & IPV6_FLOWINFO_MASK;
@@ -432,7 +429,7 @@ rip6_output(struct mbuf *m, ...)
 	ip6->ip6_plen  = htons((u_short)plen);
 #endif
 	ip6->ip6_nxt   = in6p->inp_ipv6.ip6_nxt;
-	ip6->ip6_hlim = in6_selecthlim(in6p, oifp);
+	ip6->ip6_hlim = in6_selecthlim(in6p);
 
 	if (so->so_proto->pr_protocol == IPPROTO_ICMPV6 ||
 	    in6p->inp_cksum6 != -1) {
diff --git a/sys/netinet6/udp6_output.c b/sys/netinet6/udp6_output.c
index 61144b81bfc..1d0b3f5b64b 100644
--- a/sys/netinet6/udp6_output.c
+++ b/sys/netinet6/udp6_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: udp6_output.c,v 1.38 2015/10/19 12:11:28 mpi Exp $	*/
+/*	$OpenBSD: udp6_output.c,v 1.39 2015/10/24 16:08:48 mpi Exp $	*/
 /*	$KAME: udp6_output.c,v 1.21 2001/02/07 11:51:54 itojun Exp $	*/
 
 /*
@@ -105,7 +105,6 @@ udp6_output(struct inpcb *in6p, struct mbuf *m, struct mbuf *addr6,
 	struct ip6_pktopts *optp, opt;
 	struct sockaddr_in6 tmp;
 	struct proc *p = curproc;	/* XXX */
-	struct ifnet *ifp;
 	u_short fport;
 
 	if ((in6p->inp_socket->so_state & SS_PRIV) != 0)
@@ -207,10 +206,7 @@ udp6_output(struct inpcb *in6p, struct mbuf *m, struct mbuf *addr6,
 	ip6->ip6_plen	= htons((u_short)plen);
 #endif
 	ip6->ip6_nxt	= IPPROTO_UDP;
-	ifp = NULL;
-	if (rtisvalid(in6p->inp_route6.ro_rt))
-		ifp = in6p->inp_route6.ro_rt->rt_ifp;
-	ip6->ip6_hlim	= in6_selecthlim(in6p, ifp);
+	ip6->ip6_hlim	= in6_selecthlim(in6p);
 	ip6->ip6_src	= *laddr;
 	ip6->ip6_dst	= *faddr;