svn commit: r358568 - head/sys/netinet6

[Bjoern A. Zeeb]

Author: bz
Date: Tue Mar  3 09:45:16 2020
New Revision: 358568
URL: https://svnweb.freebsd.org/changeset/base/358568

Log:
  fib6_rte_to_nh_*: return a link-local gw address with scope embedded
  
  In fib6_rte_to_nh_* when returning a link-local gateway address
  currently we do clear the scope. That could be recovered using
  the ifp returned as well, but the code in general seems to
  expect a link-local address with scope embeedded as otherwise
  the "dst" (gw) passed to the output routines will not include
  scope and not send the packet out (the right interface).
  
  Do not clear the scope when returning a link-local address and
  allow packets to go out (the right interface).
  
  Remove the (now) extra scope recovery in the IPv6 fast-fwd code.
  
  Sponsored by:	Netflix
  Reviewed by:	melifaro, ae
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D23872

Modified:
  head/sys/netinet6/in6_fib.c
  head/sys/netinet6/ip6_fastfwd.c

Modified: head/sys/netinet6/in6_fib.c
==============================================================================
--- head/sys/netinet6/in6_fib.c	Tue Mar  3 08:28:16 2020	(r358567)
+++ head/sys/netinet6/in6_fib.c	Tue Mar  3 09:45:16 2020	(r358568)
@@ -115,9 +115,9 @@ fib6_rte_to_nh_basic(struct rtentry *rte, const struct
 
 	pnh6->nh_mtu = min(rte->rt_mtu, IN6_LINKMTU(rte->rt_ifp));
 	if (rte->rt_flags & RTF_GATEWAY) {
+		/* Return address with embedded scope. */
 		gw = (struct sockaddr_in6 *)rte->rt_gateway;
 		pnh6->nh_addr = gw->sin6_addr;
-		in6_clearscope(&pnh6->nh_addr);
 	} else
 		pnh6->nh_addr = *dst;
 	/* Set flags */
@@ -143,9 +143,9 @@ fib6_rte_to_nh_extended(struct rtentry *rte, const str
 
 	pnh6->nh_mtu = min(rte->rt_mtu, IN6_LINKMTU(rte->rt_ifp));
 	if (rte->rt_flags & RTF_GATEWAY) {
+		/* Return address with embedded scope. */
 		gw = (struct sockaddr_in6 *)rte->rt_gateway;
 		pnh6->nh_addr = gw->sin6_addr;
-		in6_clearscope(&pnh6->nh_addr);
 	} else
 		pnh6->nh_addr = *dst;
 	/* Set flags */

Modified: head/sys/netinet6/ip6_fastfwd.c
==============================================================================
--- head/sys/netinet6/ip6_fastfwd.c	Tue Mar  3 08:28:16 2020	(r358567)
+++ head/sys/netinet6/ip6_fastfwd.c	Tue Mar  3 09:45:16 2020	(r358568)
@@ -274,14 +274,7 @@ passout:
 	m_clrprotoflags(m);	/* Avoid confusing lower layers. */
 	IP_PROBE(send, NULL, NULL, ip6, nh.nh_ifp, NULL, ip6);
 
-	/*
-	 * XXX: we need to use destination address with embedded scope
-	 * zone id, because LLTABLE uses such form of addresses for lookup.
-	 */
 	dst.sin6_addr = nh.nh_addr;
-	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6_addr))
-		dst.sin6_addr.s6_addr16[1] = htons(nh.nh_ifp->if_index & 0xffff);
-
 	error = (*nh.nh_ifp->if_output)(nh.nh_ifp, m,
 	    (struct sockaddr *)&dst, NULL);
 	if (error != 0) {