From 99ba58c674b16af00f55405695a33726bb620f4d Mon Sep 17 00:00:00 2001
From: mpi <mpi@openbsd.org>
Date: Tue, 19 Jul 2016 08:13:45 +0000
Subject: [PATCH] Use a flag to indicate that a packet has been received on an
 IPv6 anycast address.

This will allow us to split ip6_input() in two parts using a queue
in the middle.

ok jca@, florian@, bluhm@
---
 share/man/man9/mbuf.9    | 10 ++++------
 sys/netinet6/ip6_input.c |  8 ++++----
 sys/sys/mbuf.h           |  8 ++++----
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index a663f801599..1508832cbb5 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: mbuf.9,v 1.99 2016/04/08 10:01:12 dlg Exp $
+.\"     $OpenBSD: mbuf.9,v 1.100 2016/07/19 08:13:46 mpi Exp $
 .\"
 .\" Copyright (c) 2001 Jean-Jacques Bernard-Gundol <jjbg@openbsd.org>
 .\" All rights reserved.
@@ -25,7 +25,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: April 8 2016 $
+.Dd $Mdocdate: July 19 2016 $
 .Dt MGET 9
 .Os
 .Sh NAME
@@ -294,10 +294,8 @@ protocol-specific.
 variable is valid.
 .It Dv M_LOOP
 for mbuf statistics.
-.It Dv M_FILDROP
-dropped by
-.Xr bpf 4
-filter.
+.It Dv M_ACAST
+received as IPv6 anycast.
 .It Dv M_BCAST
 packet send/received as link-level broadcast.
 .It Dv M_MCAST
diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c
index 882d660c77e..7d4966e980c 100644
--- a/sys/netinet6/ip6_input.c
+++ b/sys/netinet6/ip6_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_input.c,v 1.164 2016/07/18 19:50:49 bluhm Exp $	*/
+/*	$OpenBSD: ip6_input.c,v 1.165 2016/07/19 08:13:46 mpi Exp $	*/
 /*	$KAME: ip6_input.c,v 1.188 2001/03/29 05:34:31 itojun Exp $	*/
 
 /*
@@ -197,7 +197,7 @@ ip6_input(struct mbuf *m)
 #if NPF > 0
 	struct in6_addr odst;
 #endif
-	int srcrt = 0, isanycast = 0;
+	int srcrt = 0;
 
 	ifp = if_get(m->m_pkthdr.ph_ifidx);
 	if (ifp == NULL)
@@ -450,7 +450,7 @@ ip6_input(struct mbuf *m)
 		struct in6_ifaddr *ia6 =
 			ifatoia6(ip6_forward_rt.ro_rt->rt_ifa);
 		if (ia6->ia6_flags & IN6_IFF_ANYCAST)
-			isanycast = 1;
+			m->m_flags |= M_ACAST;
 		/*
 		 * packets to a tentative, duplicated, or somehow invalid
 		 * address must not be accepted.
@@ -552,7 +552,7 @@ ip6_input(struct mbuf *m)
 		}
 
 		/* draft-itojun-ipv6-tcp-to-anycast */
-		if (isanycast && nxt == IPPROTO_TCP) {
+		if (ISSET(m->m_flags, M_ACAST) && (nxt == IPPROTO_TCP)) {
 			if (m->m_len >= sizeof(struct ip6_hdr)) {
 				icmp6_error(m, ICMP6_DST_UNREACH,
 					ICMP6_DST_UNREACH_ADDR,
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 35f42b41790..df56ea8d91a 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mbuf.h,v 1.215 2016/06/13 21:24:43 bluhm Exp $	*/
+/*	$OpenBSD: mbuf.h,v 1.216 2016/07/19 08:13:45 mpi Exp $	*/
 /*	$NetBSD: mbuf.h,v 1.19 1996/02/09 18:25:14 christos Exp $	*/
 
 /*
@@ -184,7 +184,7 @@ struct mbuf {
 /* mbuf pkthdr flags, also in m_flags */
 #define M_VLANTAG	0x0020	/* ether_vtag is valid */
 #define M_LOOP		0x0040	/* for Mbuf statistics */
-#define M_FILDROP	0x0080	/* dropped by bpf filter */
+#define M_ACAST		0x0080	/* received as IPv6 anycast */
 #define M_BCAST		0x0100	/* send/received as link-level broadcast */
 #define M_MCAST		0x0200	/* send/received as link-level multicast */
 #define M_CONF		0x0400  /* payload was encrypted (ESP-transport) */
@@ -197,13 +197,13 @@ struct mbuf {
 #ifdef _KERNEL
 #define M_BITS \
     ("\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_EXTWR\5M_PROTO1\6M_VLANTAG\7M_LOOP" \
-    "\10M_FILDROP\11M_BCAST\12M_MCAST\13M_CONF\14M_AUTH\15M_TUNNEL" \
+    "\10M_ACAST\11M_BCAST\12M_MCAST\13M_CONF\14M_AUTH\15M_TUNNEL" \
     "\16M_ZEROIZE\17M_COMP\20M_LINK0")
 #endif
 
 /* flags copied when copying m_pkthdr */
 #define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST|M_CONF|M_COMP|\
-			 M_AUTH|M_LOOP|M_TUNNEL|M_LINK0|M_VLANTAG|M_FILDROP|\
+			 M_AUTH|M_LOOP|M_TUNNEL|M_LINK0|M_VLANTAG|M_ACAST|\
 			 M_ZEROIZE)
 
 /* Checksumming flags */
-- 
2.20.1