Use FF02:0:0:0:0:2:FF00::/104 prefix for IPv6 Node Information Group

Address.  Although KAME implementation used FF02:0:0:0:0:2::/96 based on
older versions of draft-ietf-ipngwg-icmp-name-lookup, it has been changed
in RFC 4620.

The kernel always joins the /104-prefixed address, and additionally does
/96-prefixed one only when net.inet6.icmp6.nodeinfo_oldmcprefix=1.
The default value of the sysctl is 1.

ping6(8) -N flag now uses /104-prefixed one.  When this flag is specified
twice, it uses /96-prefixed one instead.

Reviewed by:		ume
Based on work by:	Thomas Scheffler
PR:			conf/174957
MFC after:		2 weeks

4 files changed, 53 insertions, 6 deletions

diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 934665c..5a90111 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -106,6 +106,9 @@ __FBSDID("$FreeBSD$");
 #include <netinet6/scope6_var.h>
 #include <netinet6/in6_pcb.h>
 
+VNET_DECLARE(int, icmp6_nodeinfo_oldmcprefix);
+#define V_icmp6_nodeinfo_oldmcprefix	VNET(icmp6_nodeinfo_oldmcprefix)
+
 /*
  * Definitions of some costant IP6 addresses.
  */
@@ -947,6 +950,17 @@ in6_update_ifa_join_mc(struct ifnet *ifp, struct in6_aliasreq *ifra,
 		else
 			LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
 	}
+	if (V_icmp6_nodeinfo_oldmcprefix && 
+	     in6_nigroup_oldmcprefix(ifp, NULL, -1, &mltaddr.sin6_addr) == 0) {
+		imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error, delay);
+		if (imm == NULL)
+			nd6log((LOG_WARNING, "%s: addmulti failed for %s on %s "
+			    "(errno=%d)\n", __func__, ip6_sprintf(ip6buf,
+			    &mltaddr.sin6_addr), if_name(ifp), error));
+			/* XXX not very fatal, go on... */
+		else
+			LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
+	}
 
 	/*
 	 * Join interface-local all-nodes address.
diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 28ec920..85890ab 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -616,13 +616,16 @@ in6_ifattach_loopback(struct ifnet *ifp)
 
 /*
  * compute NI group address, based on the current hostname setting.
- * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
+ * see RFC 4620.
  *
  * when ifp == NULL, the caller is responsible for filling scopeid.
+ *
+ * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
+ * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620. 
  */
-int
-in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
-    struct in6_addr *in6)
+static int
+in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
+    struct in6_addr *in6, int oldmcprefix)
 {
 	struct prison *pr;
 	const char *p;
@@ -667,7 +670,7 @@ in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
 			*q = *q - 'A' + 'a';
 	}
 
-	/* generate 8 bytes of pseudo-random value. */
+	/* generate 16 bytes of pseudo-random value. */
 	bzero(&ctxt, sizeof(ctxt));
 	MD5Init(&ctxt);
 	MD5Update(&ctxt, &l, sizeof(l));
@@ -677,13 +680,36 @@ in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
 	bzero(in6, sizeof(*in6));
 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
 	in6->s6_addr8[11] = 2;
-	bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
+	if (oldmcprefix == 0) {
+		in6->s6_addr8[12] = 0xff;
+	 	/* Copy the first 24 bits of 128-bit hash into the address. */
+		bcopy(digest, &in6->s6_addr8[13], 3);
+	} else {
+	 	/* Copy the first 32 bits of 128-bit hash into the address. */
+		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
+	}
 	if (in6_setscope(in6, ifp, NULL))
 		return (-1); /* XXX: should not fail */
 
 	return 0;
 }
 
+int
+in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
+    struct in6_addr *in6)
+{
+
+	return (in6_nigroup0(ifp, name, namelen, in6, 0));
+}
+
+int
+in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
+    struct in6_addr *in6)
+{
+
+	return (in6_nigroup0(ifp, name, namelen, in6, 1));
+}
+
 /*
  * XXX multiple loopback interface needs more care.  for instance,
  * nodelocal address needs to be configured onto only one of them.
diff --git a/sys/netinet6/in6_ifattach.h b/sys/netinet6/in6_ifattach.h
index 113c427..af62731 100644
--- a/sys/netinet6/in6_ifattach.h
+++ b/sys/netinet6/in6_ifattach.h
@@ -40,6 +40,7 @@ int in6_get_tmpifid(struct ifnet *, u_int8_t *, const u_int8_t *, int);
 void in6_tmpaddrtimer(void *);
 int in6_get_hw_ifid(struct ifnet *, struct in6_addr *);
 int in6_nigroup(struct ifnet *, const char *, int, struct in6_addr *);
+int in6_nigroup_oldmcprefix(struct ifnet *, const char *, int, struct in6_addr *);
 #endif /* _KERNEL */
 
 #endif /* _NETINET6_IN6_IFATTACH_H_ */
diff --git a/sys/netinet6/in6_proto.c b/sys/netinet6/in6_proto.c
index ede1f9d..a1efac4 100644
--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -438,6 +438,7 @@ VNET_DEFINE(int, icmp6errppslim) = 100;		/* 100pps */
 /* control how to respond to NI queries */
 VNET_DEFINE(int, icmp6_nodeinfo) =
     (ICMP6_NODEINFO_FQDNOK|ICMP6_NODEINFO_NODEADDROK);
+VNET_DEFINE(int, icmp6_nodeinfo_oldmcprefix) = 1;
 
 /*
  * sysctl related items.
@@ -602,6 +603,11 @@ SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_USELOOPBACK, nd6_useloopback,
 	CTLFLAG_RW, &VNET_NAME(nd6_useloopback), 0, "");
 SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_NODEINFO, nodeinfo, CTLFLAG_RW,
 	&VNET_NAME(icmp6_nodeinfo), 0, "");
+SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_NODEINFO_OLDMCPREFIX,
+	nodeinfo_oldmcprefix, CTLFLAG_RW,
+	&VNET_NAME(icmp6_nodeinfo_oldmcprefix), 0, 
+	"Join old IPv6 NI group address in draft-ietf-ipngwg-icmp-name-lookup"
+	" for compatibility with KAME implememtation.");
 SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ERRPPSLIMIT, errppslimit,
 	CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0, "");
 SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_MAXNUDHINT, nd6_maxnudhint,