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Update for IETF draft-ietf-6man-ipv6only-flag.

Browse Source 
All changes are hidden behind the EXPERIMENTAL option and are not compiled
in by default.

Add ND6_IFF_IPV6_ONLY_MANUAL to be able to set the interface into no-IPv4-mode
manually without router advertisement options.  This will allow developers to
test software for the appropriate behaviour even on dual-stack networks or
IPv6-Only networks without the option being set in RA messages.
Update ifconfig to allow setting and displaying the flag.

Update the checks for the filters to check for either the automatic or the manual
flag to be set.  Add REVARP to the list of filtered IPv4-related protocols and add
an input filter similar to the output filter.

Add a check, when receiving the IPv6-Only RA flag to see if the receiving
interface has any IPv4 configured.  If it does, ignore the IPv6-Only flag.

Add a per-VNET global sysctl, which is on by default, to not process the automatic
RA IPv6-Only flag.  This way an administrator (if this is compiled in) has control
over the behaviour in case the node still relies on IPv4.
This commit is contained in:
Bjoern A. Zeeb 2019-03-06 23:31:42 +00:00
parent e7df98863b
commit 21231a7aa6
8 changed files with 98 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sbin/ifconfig/Makefile
View File

@ -55,6 +55,7 @@ SRCS+= iflagg.c # lagg support
.if ${MK_EXPERIMENTAL} != "no"
CFLAGS+= -DDRAFT_IETF_6MAN_IPV6ONLY_FLAG
CFLAGS+= -DEXPERIMENTAL
.endif
.if ${MK_INET6_SUPPORT} != "no"
CFLAGS+= -DINET6

4
sbin/ifconfig/af_inet6.c
View File

@ -505,6 +505,10 @@ static struct cmd inet6_cmds[] = {
DEF_CMD_ARG("pltime", setip6pltime),
DEF_CMD_ARG("vltime", setip6vltime),
DEF_CMD("eui64", 0, setip6eui64),
#ifdef EXPERIMENTAL
DEF_CMD("ipv6_only", ND6_IFF_IPV6_ONLY_MANUAL,setnd6flags),
DEF_CMD("-ipv6_only", -ND6_IFF_IPV6_ONLY_MANUAL,setnd6flags),
#endif
};
static struct afswtch af_inet6 = {

2
sbin/ifconfig/af_nd6.c
View File

@ -61,7 +61,7 @@ static const char rcsid[] =
#define ND6BITS "\020\001PERFORMNUD\002ACCEPT_RTADV\003PREFER_SOURCE" \
"\004IFDISABLED\005DONT_SET_IFROUTE\006AUTO_LINKLOCAL" \
"\007NO_RADR\010NO_PREFER_IFACE\011NO_DAD" \
"\012IPV6_ONLY" \
"\012IPV6_ONLY\013IPV6_ONLY_MANUAL" \
"\020DEFAULTIF"
#else
#define ND6BITS "\020\001PERFORMNUD\002ACCEPT_RTADV\003PREFER_SOURCE" \

24
sys/net/if_ethersubr.c
View File

@ -476,14 +476,15 @@ ether_output_frame(struct ifnet *ifp, struct mbuf *m)
#ifdef EXPERIMENTAL
#if defined(INET6) && defined(INET)
/* draft-ietf-6man-ipv6only-flag */
/* Catch ETHERTYPE_IP, and ETHERTYPE_ARP if we are v6-only. */
if ((ND_IFINFO(ifp)->flags & ND6_IFF_IPV6_ONLY) != 0) {
/* Catch ETHERTYPE_IP, and ETHERTYPE_[REV]ARP if we are v6-only. */
if ((ND_IFINFO(ifp)->flags & ND6_IFF_IPV6_ONLY_MASK) != 0) {
struct ether_header *eh;
eh = mtod(m, struct ether_header *);
switch (ntohs(eh->ether_type)) {
case ETHERTYPE_IP:
case ETHERTYPE_ARP:
case ETHERTYPE_REVARP:
m_freem(m);
return (EAFNOSUPPORT);
/* NOTREACHED */
@ -534,6 +535,25 @@ ether_input_internal(struct ifnet *ifp, struct mbuf *m)
etype = ntohs(eh->ether_type);
random_harvest_queue_ether(m, sizeof(*m));
#ifdef EXPERIMENTAL
#if defined(INET6) && defined(INET)
/* draft-ietf-6man-ipv6only-flag */
/* Catch ETHERTYPE_IP, and ETHERTYPE_[REV]ARP if we are v6-only. */
if ((ND_IFINFO(ifp)->flags & ND6_IFF_IPV6_ONLY_MASK) != 0) {
switch (etype) {
case ETHERTYPE_IP:
case ETHERTYPE_ARP:
case ETHERTYPE_REVARP:
m_freem(m);
return;
/* NOTREACHED */
break;
};
}
#endif
#endif
CURVNET_SET_QUIET(ifp->if_vnet);
if (ETHER_IS_MULTICAST(eh->ether_dhost)) {

7
sys/netinet6/in6_proto.c
View File

@ -641,3 +641,10 @@ SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_ONLINKNSRFC4861,
nd6_onlink_ns_rfc4861, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(nd6_onlink_ns_rfc4861), 0,
"Accept 'on-link' ICMPv6 NS messages in compliance with RFC 4861");
#ifdef EXPERIMENTAL
SYSCTL_INT(_net_inet6_icmp6, OID_AUTO,
nd6_ignore_ipv6_only_ra, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(nd6_ignore_ipv6_only_ra), 0,
"Ignore the 'IPv6-Only flag' in RA messages in compliance with "
"draft-ietf-6man-ipv6only-flag");
#endif

5
sys/netinet6/ip6_var.h
View File

@ -355,6 +355,11 @@ VNET_DECLARE(int, ip6stealth);
#define V_ip6stealth VNET(ip6stealth)
#endif
#ifdef EXPERIMENTAL
VNET_DECLARE(int, nd6_ignore_ipv6_only_ra);
#define V_nd6_ignore_ipv6_only_ra VNET(nd6_ignore_ipv6_only_ra)
#endif
extern struct pr_usrreqs rip6_usrreqs;
struct sockopt;

3
sys/netinet6/nd6.h
View File

@ -91,7 +91,10 @@ struct nd_ifinfo {
#define ND6_IFF_NO_PREFER_IFACE 0x80 /* XXX: not related to ND. */
#define ND6_IFF_NO_DAD 0x100
#ifdef EXPERIMENTAL
/* XXX: not related to ND. */
#define ND6_IFF_IPV6_ONLY 0x200 /* draft-ietf-6man-ipv6only-flag */
#define ND6_IFF_IPV6_ONLY_MANUAL 0x400
#define ND6_IFF_IPV6_ONLY_MASK (ND6_IFF_IPV6_ONLY|ND6_IFF_IPV6_ONLY_MANUAL)
#endif
#ifdef _KERNEL

58
sys/netinet6/nd6_rtr.c
View File

@ -106,6 +106,10 @@ VNET_DEFINE(u_int32_t, ip6_temp_valid_lifetime) = DEF_TEMP_VALID_LIFETIME;
VNET_DEFINE(int, ip6_temp_regen_advance) = TEMPADDR_REGEN_ADVANCE;
#ifdef EXPERIMENTAL
VNET_DEFINE(int, nd6_ignore_ipv6_only_ra) = 1;
#endif
/* RTPREF_MEDIUM has to be 0! */
#define RTPREF_HIGH 1
#define RTPREF_MEDIUM 0
@ -208,7 +212,7 @@ nd6_rs_input(struct mbuf *m, int off, int icmp6len)
/*
* An initial update routine for draft-ietf-6man-ipv6only-flag.
* We need to iterate over all default routers for the given
* interface to see whether they are all advertising the "6"
* interface to see whether they are all advertising the "S"
* (IPv6-Only) flag. If they do set, otherwise unset, the
* interface flag we later use to filter on.
*/
@ -216,7 +220,15 @@ static void
defrtr_ipv6_only_ifp(struct ifnet *ifp)
{
struct nd_defrouter *dr;
bool ipv6_only;
bool ipv6_only, ipv6_only_old;
#ifdef INET
struct epoch_tracker et;
struct ifaddr *ifa;
bool has_ipv4_addr;
#endif
if (V_nd6_ignore_ipv6_only_ra != 0)
return;
ipv6_only = true;
ND6_RLOCK();
@ -226,14 +238,54 @@ defrtr_ipv6_only_ifp(struct ifnet *ifp)
ipv6_only = false;
ND6_RUNLOCK();
IF_AFDATA_WLOCK(ifp);
ipv6_only_old = ND_IFINFO(ifp)->flags & ND6_IFF_IPV6_ONLY;
IF_AFDATA_WUNLOCK(ifp);
/* If nothing changed, we have an early exit. */
if (ipv6_only == ipv6_only_old)
return;
#ifdef INET
/*
* Should we want to set the IPV6-ONLY flag, check if the
* interface has a non-0/0 and non-link-local IPv4 address
* configured on it. If it has we will assume working
* IPv4 operations and will clear the interface flag.
*/
has_ipv4_addr = false;
if (ipv6_only) {
NET_EPOCH_ENTER(et);
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
if (in_canforward(
satosin(ifa->ifa_addr)->sin_addr)) {
has_ipv4_addr = true;
break;
}
}
NET_EPOCH_EXIT(et);
}
if (ipv6_only && has_ipv4_addr) {
log(LOG_NOTICE, "%s rcvd RA w/ IPv6-Only flag set but has IPv4 "
"configured, ignoring IPv6-Only flag.\n", ifp->if_xname);
ipv6_only = false;
}
#endif
IF_AFDATA_WLOCK(ifp);
if (ipv6_only)
ND_IFINFO(ifp)->flags |= ND6_IFF_IPV6_ONLY;
else
ND_IFINFO(ifp)->flags &= ~ND6_IFF_IPV6_ONLY;
IF_AFDATA_WUNLOCK(ifp);
}
#ifdef notyet
/* Send notification of flag change. */
#endif
}
#endif /* EXPERIMENTAL */
/*
* Receive Router Advertisement Message.