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Date: Mon, 22 Jan 2007 13:15:28 -0500
From: Neil Horman <nhorman@...driver.com>
To: yoshfuji@...ux-ipv6.org
Cc: 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 Sat, Jan 20, 2007 at 08:05:07AM +0900, YOSHIFUJI Hideaki / 吉藤英明 wrote:
> Hello.
>
> In article <20070119212314.GA10748@...reliant.homelinux.net> (at Fri, 19 Jan 2007 16:23:14 -0500), Neil Horman <nhorman@...driver.com> says:
>
> > Patch to Implement IPv6 RFC 4429 (Optimistic Duplicate Address Detection). In
>
> Good work. We will see if this would break core and basic ipv6 code.
> Dave, please hold on.
>
> Some quick comments.
> --yoshfuji
<snip>
Reposted patch, with your suggestions/corrections incorporated. The only thing
I left alone was your last comment regarding the checking of saddr for being a
unicast address. According to the RFC as I read it, its possible to receive
valid neighbor soliciations with a source address that is the unspecified
address, which I didn't think ipv6_addr_type flagged as being unicast. Now it
may be that such NS messages are discarded before arriving at that recieve
routine, but I was figuring better safe than sorry. If you're sufficiently
confident that we won't see non-unicast saddrs there, let me know and I'll
happily remove that as well.
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 | 59 ++++++++++++++++++++++++++++++++++++++++--------
7 files changed, 105 insertions(+), 20 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..9edbf9d 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
@@ -796,11 +823,13 @@ 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) {
+
+ if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
/* Address is tentative. If the source
- is unspecified address, it is someone
- does DAD, otherwise we ignore solicitations
- until DAD timer expires.
+ is unspecified address, someone else
+ is doing DAD, and if its not us, then
+ we need to fail our own DAD
+ RFC 4429 Sec 3.3
*/
if (!dad)
goto out;
@@ -816,8 +845,20 @@ 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.
+ */
+ type = ipv6_addr_type(saddr);
+ if (!((ifp->flags & IFA_F_OPTIMISTIC) &&
+ (type & IPV6_ADDR_UNICAST))) {
+ addrconf_dad_failure(ifp);
+ return;
+ }
}
idev = ifp->idev;
@@ -1406,7 +1447,7 @@ 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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