ipv6: do retries on stable privacy addresses
If a DAD conflict is detected, we want to retry privacy stable address
generation up to idgen_retries (= 3) times with a delay of idgen_delay
(= 1 second). Add the logic to addrconf_dad_failure.
By design, we don't clean up dad failed permanent addresses.
Cc: Erik Kline <ek@google.com>
Cc: Fernando Gont <fgont@si6networks.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: YOSHIFUJI Hideaki/吉藤英明 <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index d89397a2..1c8b682 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -52,6 +52,7 @@
__u32 flags;
__u8 dad_probes;
+ __u8 stable_privacy_retry;
__u16 scope;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1cc5320..9b51fdb 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1710,6 +1710,7 @@
void addrconf_dad_failure(struct inet6_ifaddr *ifp)
{
+ struct in6_addr addr;
struct inet6_dev *idev = ifp->idev;
if (addrconf_dad_end(ifp)) {
@@ -1720,9 +1721,59 @@
net_info_ratelimited("%s: IPv6 duplicate address %pI6c detected!\n",
ifp->idev->dev->name, &ifp->addr);
- if (idev->cnf.accept_dad > 1 && !idev->cnf.disable_ipv6) {
- struct in6_addr addr;
+ spin_lock_bh(&ifp->lock);
+ if (ifp->flags & IFA_F_STABLE_PRIVACY) {
+ int scope = ifp->scope;
+ u32 flags = ifp->flags;
+ struct in6_addr new_addr;
+ struct inet6_ifaddr *ifp2;
+ u32 valid_lft, preferred_lft;
+ int pfxlen = ifp->prefix_len;
+ const unsigned int idgen_retries = 3;
+ const unsigned int idgen_delay = 1 * HZ;
+ int retries = ifp->stable_privacy_retry + 1;
+
+ if (retries > idgen_retries) {
+ net_info_ratelimited("%s: privacy stable address generation failed because of DAD conflicts!\n",
+ ifp->idev->dev->name);
+ goto errdad;
+ }
+
+ new_addr = ifp->addr;
+ if (ipv6_generate_stable_address(&new_addr, retries,
+ idev))
+ goto errdad;
+
+ valid_lft = ifp->valid_lft;
+ preferred_lft = ifp->prefered_lft;
+
+ spin_unlock_bh(&ifp->lock);
+
+ if (idev->cnf.max_addresses &&
+ ipv6_count_addresses(idev) >=
+ idev->cnf.max_addresses)
+ goto lock_errdad;
+
+ net_info_ratelimited("%s: generating new stable privacy address because of DAD conflict\n",
+ ifp->idev->dev->name);
+
+ ifp2 = ipv6_add_addr(idev, &new_addr, NULL, pfxlen,
+ scope, flags, valid_lft,
+ preferred_lft);
+ if (IS_ERR(ifp2))
+ goto lock_errdad;
+
+ spin_lock_bh(&ifp2->lock);
+ ifp2->stable_privacy_retry = retries;
+ ifp2->state = INET6_IFADDR_STATE_PREDAD;
+ spin_unlock_bh(&ifp2->lock);
+
+ addrconf_mod_dad_work(ifp2, idgen_delay);
+ in6_ifa_put(ifp2);
+lock_errdad:
+ spin_lock_bh(&ifp->lock);
+ } else if (idev->cnf.accept_dad > 1 && !idev->cnf.disable_ipv6) {
addr.s6_addr32[0] = htonl(0xfe800000);
addr.s6_addr32[1] = 0;
@@ -1736,7 +1787,7 @@
}
}
- spin_lock_bh(&ifp->lock);
+errdad:
/* transition from _POSTDAD to _ERRDAD */
ifp->state = INET6_IFADDR_STATE_ERRDAD;
spin_unlock_bh(&ifp->lock);