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Date: Mon, 22 Jan 2007 14:45:48 -0500
From: Neil Horman <nhorman@...driver.com>
To: Mika Penttilä <mika.penttila@...umbus.fi>
Cc: yoshfuji@...ux-ipv6.org, davem@...emloft.net, kuznet@....inr.ac.ru,
pekkas@...core.fi, jmorris@...ei.org, kaber@...eworks.de,
netdev@...r.kernel.org
Subject: Re: [PATCH] IPv6: Implement RFC 4429 Optimistic Duplicate Address Detection
On Mon, Jan 22, 2007 at 08:39:24PM +0200, Mika Penttilä wrote:
> Neil Horman wrote:
><snip >
> I think you should remove / modify the :
> if (!dad)
> goto out;
>
> which makes the rfc4429 tests not functional.
>
> --Mika
>
Yeah, I think you're right. In fact, as I look at it more closely I think that
logic for NS message recives is a bit confused overall. Section 3.3 of RFC 4429
says that I should fail DAD if I'm optimistic and I get an NS from the
unspecified address, but I must reply to an NS from a unicast address. The way
the logic is written, I was going to fail dad if the address was just tentative
(i.e. odad was disabled), which is a deviation from the nominal behavior. And
of course, as you mention, the (!dad) clause kills the odad tests (although it
is still required if we are not an optimistic address). This updated patch
should take care of all that, as well as make that logic more clear
Thanks & Regards
Neil
Signed-off-by: Neil Horman <nhorman@...driver.com>
include/linux/if_addr.h | 1
include/linux/ipv6.h | 1
include/linux/sysctl.h | 1
include/net/addrconf.h | 4 ++-
net/ipv6/addrconf.c | 55 ++++++++++++++++++++++++++++++++++++------
net/ipv6/mcast.c | 4 +--
net/ipv6/ndisc.c | 62 +++++++++++++++++++++++++++++++++++++-----------
7 files changed, 104 insertions(+), 24 deletions(-)
diff --git a/include/linux/if_addr.h b/include/linux/if_addr.h
index d557e4c..43f3bed 100644
--- a/include/linux/if_addr.h
+++ b/include/linux/if_addr.h
@@ -39,6 +39,7 @@ enum
#define IFA_F_TEMPORARY IFA_F_SECONDARY
#define IFA_F_NODAD 0x02
+#define IFA_F_OPTIMISTIC 0x04
#define IFA_F_HOMEADDRESS 0x10
#define IFA_F_DEPRECATED 0x20
#define IFA_F_TENTATIVE 0x40
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index f824113..1a8edc1 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -176,6 +176,7 @@ struct ipv6_devconf {
__s32 accept_ra_rt_info_max_plen;
#endif
#endif
+ __s32 use_optimistic_dad;
__s32 proxy_ndp;
void *sysctl;
};
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 81480e6..972a33a 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -570,6 +570,7 @@ enum {
NET_IPV6_RTR_PROBE_INTERVAL=21,
NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN=22,
NET_IPV6_PROXY_NDP=23,
+ NET_IPV6_OPTIMISTIC_DAD=24,
__NET_IPV6_MAX
};
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 88df8fc..d248a19 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -73,7 +73,9 @@ extern int ipv6_get_saddr(struct dst_entry *dst,
extern int ipv6_dev_get_saddr(struct net_device *dev,
struct in6_addr *daddr,
struct in6_addr *saddr);
-extern int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *);
+extern int ipv6_get_lladdr(struct net_device *dev,
+ struct in6_addr *,
+ unsigned char banned_flags);
extern int ipv6_rcv_saddr_equal(const struct sock *sk,
const struct sock *sk2);
extern void addrconf_join_solict(struct net_device *dev,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2a7e461..316d771 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -830,7 +830,8 @@ retry:
ift = !max_addresses ||
ipv6_count_addresses(idev) < max_addresses ?
ipv6_add_addr(idev, &addr, tmp_plen,
- ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK, IFA_F_TEMPORARY) : NULL;
+ ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK,
+ IFA_F_TEMPORARY|IFA_F_OPTIMISTIC) : NULL;
if (!ift || IS_ERR(ift)) {
in6_ifa_put(ifp);
in6_dev_put(idev);
@@ -1174,7 +1175,8 @@ int ipv6_get_saddr(struct dst_entry *dst,
}
-int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)
+int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
+ unsigned char banned_flags)
{
struct inet6_dev *idev;
int err = -EADDRNOTAVAIL;
@@ -1185,7 +1187,7 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)
read_lock_bh(&idev->lock);
for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {
- if (ifp->scope == IFA_LINK && !(ifp->flags&IFA_F_TENTATIVE)) {
+ if (ifp->scope == IFA_LINK && !(ifp->flags & banned_flags)) {
ipv6_addr_copy(addr, &ifp->addr);
err = 0;
break;
@@ -1751,6 +1753,7 @@ ok:
update_lft = create = 1;
ifp->cstamp = jiffies;
+ ifp->flags |= IFA_F_OPTIMISTIC;
addrconf_dad_start(ifp, RTF_ADDRCONF|RTF_PREFIX_RT);
}
@@ -1945,7 +1948,11 @@ static int inet6_addr_add(int ifindex, struct in6_addr *pfx, int plen,
ifp->prefered_lft = prefered_lft;
ifp->tstamp = jiffies;
spin_unlock_bh(&ifp->lock);
-
+ /*
+ * Note that section 3.1 of RFC 4429 indicates
+ * That the Optimistic flag should not be set for
+ * manually configured addresses
+ */
addrconf_dad_start(ifp, 0);
in6_ifa_put(ifp);
addrconf_verify(0);
@@ -2123,7 +2130,8 @@ static void addrconf_add_linklocal(struct inet6_dev *idev, struct in6_addr *addr
{
struct inet6_ifaddr * ifp;
- ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK, IFA_F_PERMANENT);
+ ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK,
+ IFA_F_PERMANENT|IFA_F_OPTIMISTIC);
if (!IS_ERR(ifp)) {
addrconf_dad_start(ifp, 0);
in6_ifa_put(ifp);
@@ -2190,7 +2198,7 @@ ipv6_inherit_linklocal(struct inet6_dev *idev, struct net_device *link_dev)
{
struct in6_addr lladdr;
- if (!ipv6_get_lladdr(link_dev, &lladdr)) {
+ if (!ipv6_get_lladdr(link_dev, &lladdr, IFA_F_TENTATIVE)) {
addrconf_add_linklocal(idev, &lladdr);
return 0;
}
@@ -2537,8 +2545,18 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
struct inet6_dev *idev = ifp->idev;
struct net_device *dev = idev->dev;
+ if (!idev->cnf.use_optimistic_dad)
+ ifp->flags &= ~IFA_F_OPTIMISTIC;
+
addrconf_join_solict(dev, &ifp->addr);
+ /*
+ * Optimistic nodes need to joing the anycast address
+ * right away
+ */
+ if (ifp->flags & IFA_F_OPTIMISTIC)
+ addrconf_join_anycast(ifp);
+
if (ifp->prefix_len != 128 && (ifp->flags&IFA_F_PERMANENT))
addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev, 0,
flags);
@@ -2553,7 +2571,7 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
!(ifp->flags&IFA_F_TENTATIVE) ||
ifp->flags & IFA_F_NODAD) {
- ifp->flags &= ~IFA_F_TENTATIVE;
+ ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);
spin_unlock_bh(&ifp->lock);
read_unlock_bh(&idev->lock);
@@ -2573,6 +2591,18 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
addrconf_dad_stop(ifp);
return;
}
+
+ /*
+ * Forwarding devices (routers) should not use
+ * optimistic addresses
+ * Nor should interfaces that don't know the
+ * Source address for their default gateway
+ * RFC 4429 Sec 3.3
+ */
+ if ((ipv6_devconf.forwarding) ||
+ (ifp->rt == NULL))
+ ifp->flags &= ~IFA_F_OPTIMISTIC;
+
addrconf_dad_kick(ifp);
spin_unlock_bh(&ifp->lock);
out:
@@ -2597,7 +2627,7 @@ static void addrconf_dad_timer(unsigned long data)
* DAD was successful
*/
- ifp->flags &= ~IFA_F_TENTATIVE;
+ ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);
spin_unlock_bh(&ifp->lock);
read_unlock_bh(&idev->lock);
@@ -3918,6 +3948,15 @@ static struct addrconf_sysctl_table
.proc_handler = &proc_dointvec,
},
{
+ .ctl_name = NET_IPV6_OPTIMISTIC_DAD,
+ .procname = "use_optimistic_dad",
+ .data = &ipv6_devconf.use_optimistic_dad,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+
+ },
+ {
.ctl_name = 0, /* sentinel */
}
},
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 882cde4..9c5273c 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1411,7 +1411,7 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
skb_reserve(skb, LL_RESERVED_SPACE(dev));
- if (ipv6_get_lladdr(dev, &addr_buf)) {
+ if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
/* <draft-ietf-magma-mld-source-05.txt>:
* use unspecified address as the source address
* when a valid link-local address is not available.
@@ -1789,7 +1789,7 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
skb_reserve(skb, LL_RESERVED_SPACE(dev));
- if (ipv6_get_lladdr(dev, &addr_buf)) {
+ if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
/* <draft-ietf-magma-mld-source-05.txt>:
* use unspecified address as the source address
* when a valid link-local address is not available.
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 6a9f616..bb872ef 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -498,7 +498,21 @@ static void ndisc_send_na(struct net_device *dev, struct neighbour *neigh,
msg->icmph.icmp6_unused = 0;
msg->icmph.icmp6_router = router;
msg->icmph.icmp6_solicited = solicited;
- msg->icmph.icmp6_override = override;
+ if (!ifp || !(ifp->flags & IFA_F_OPTIMISTIC))
+ msg->icmph.icmp6_override = override;
+ else {
+ /*
+ * We must clear the override flag on all
+ * neighbor advertisements from source
+ * addresses that are OPTIMISTIC - RFC 4429
+ * section 2.2
+ */
+ if (override)
+ printk(KERN_WARNING
+ "Disallowing override flag for OPTIMISTIC addr\n");
+ msg->icmph.icmp6_override = 0;
+ }
+
/* Set the target address. */
ipv6_addr_copy(&msg->target, solicited_addr);
@@ -542,7 +556,8 @@ void ndisc_send_ns(struct net_device *dev, struct neighbour *neigh,
int send_llinfo;
if (saddr == NULL) {
- if (ipv6_get_lladdr(dev, &addr_buf))
+ if (ipv6_get_lladdr(dev, &addr_buf,
+ (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)))
return;
saddr = &addr_buf;
}
@@ -622,9 +637,20 @@ void ndisc_send_rs(struct net_device *dev, struct in6_addr *saddr,
struct sk_buff *skb;
struct icmp6hdr *hdr;
__u8 * opt;
+ struct inet6_ifaddr *ifp;
int len;
int err;
+ /*
+ * Check the source address. If its OPTIMISTIC
+ * and addr_len is non-zero (implying the sllao option)
+ * then don't send the RS (RFC 4429, section 2.2)
+ */
+ ifp = ipv6_get_ifaddr(saddr, dev, 1);
+
+ if ((!ifp) || ((ifp->flags & IFA_F_OPTIMISTIC) && dev->addr_len))
+ return;
+
ndisc_flow_init(&fl, NDISC_ROUTER_SOLICITATION, saddr, daddr,
dev->ifindex);
@@ -746,6 +772,7 @@ static void ndisc_recv_ns(struct sk_buff *skb)
int dad = ipv6_addr_any(saddr);
int inc;
int is_router;
+ int type;
if (ipv6_addr_is_multicast(&msg->target)) {
ND_PRINTK2(KERN_WARNING
@@ -796,14 +823,8 @@ static void ndisc_recv_ns(struct sk_buff *skb)
inc = ipv6_addr_is_multicast(daddr);
if ((ifp = ipv6_get_ifaddr(&msg->target, dev, 1)) != NULL) {
- if (ifp->flags & IFA_F_TENTATIVE) {
- /* Address is tentative. If the source
- is unspecified address, it is someone
- does DAD, otherwise we ignore solicitations
- until DAD timer expires.
- */
- if (!dad)
- goto out;
+
+ if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
if (dev->type == ARPHRD_IEEE802_TR) {
unsigned char *sadr = skb->mac.raw;
if (((sadr[8] ^ dev->dev_addr[0]) & 0x7f) == 0 &&
@@ -816,8 +837,23 @@ static void ndisc_recv_ns(struct sk_buff *skb)
goto out;
}
}
- addrconf_dad_failure(ifp);
- return;
+
+ /* The one exception to the above rule about
+ optimistic addresses is that we need to always
+ respond to an NS from a unicast address if we are
+ optimistic. RFC 4429 Sec 3.3. If (unicast
+ and optimistic) are false then we can just fail
+ dad now.
+ */
+ if (ifp->flags & IFA_F_OPTIMISTIC) {
+ type = ipv6_addr_type(saddr);
+ if (!(type & IPV6_ADDR_UNICAST)) {
+ addrconf_dad_failure(ifp);
+ goto out;
+ }
+ } else
+ if (!dad)
+ goto out;
}
idev = ifp->idev;
@@ -1406,7 +1442,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
dev = skb->dev;
- if (ipv6_get_lladdr(dev, &saddr_buf)) {
+ if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
ND_PRINTK2(KERN_WARNING
"ICMPv6 Redirect: no link-local address on %s\n",
dev->name);
-
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