diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 24ce97f42d3552cc8ddd9a1de0855a1acb9bdf06..d5df40c75aa4e855c1c9aef5874bd428a001ca06 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1563,6 +1563,15 @@ temp_prefered_lft - INTEGER
Preferred lifetime (in seconds) for temporary addresses.
Default: 86400 (1 day)
+keep_addr_on_down - INTEGER
+ Keep all IPv6 addresses on an interface down event. If set static
+ global addresses with no expiration time are not flushed.
+ >0 : enabled
+ 0 : system default
+ <0 : disabled
+
+ Default: 0 (addresses are removed)
+
max_desync_factor - INTEGER
Maximum value for DESYNC_FACTOR, which is a random value
that ensures that clients don't synchronize with each
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 4b2267e1b7c3300487b0dffab84326d259fb3822..7edc14fb66b6870298b7927e0727931d72342c1b 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -62,6 +62,7 @@ struct ipv6_devconf {
struct in6_addr secret;
} stable_secret;
__s32 use_oif_addrs_only;
+ __s32 keep_addr_on_down;
void *sysctl;
};
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index ec117b65d5a519c7c524b03b20a7522a6b1e1113..395876060f5087983cfae103b8ed8c16c30bde50 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -176,6 +176,7 @@ enum {
DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN,
DEVCONF_DROP_UNICAST_IN_L2_MULTICAST,
DEVCONF_DROP_UNSOLICITED_NA,
+ DEVCONF_KEEP_ADDR_ON_DOWN,
DEVCONF_MAX
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 4751f8922362109786622e60f4e34a19ea55dcc9..a2d6f6c242af107fea311875d6b736458ea85fbb 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -216,6 +216,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
},
.use_oif_addrs_only = 0,
.ignore_routes_with_linkdown = 0,
+ .keep_addr_on_down = 0,
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -260,6 +261,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
},
.use_oif_addrs_only = 0,
.ignore_routes_with_linkdown = 0,
+ .keep_addr_on_down = 0,
};
/* Check if a valid qdisc is available */
@@ -3168,6 +3170,55 @@ static void addrconf_gre_config(struct net_device *dev)
}
#endif
+static int fixup_permanent_addr(struct inet6_dev *idev,
+ struct inet6_ifaddr *ifp)
+{
+ if (!ifp->rt) {
+ struct rt6_info *rt;
+
+ rt = addrconf_dst_alloc(idev, &ifp->addr, false);
+ if (unlikely(IS_ERR(rt)))
+ return PTR_ERR(rt);
+
+ ifp->rt = rt;
+ }
+
+ if (!(ifp->flags & IFA_F_NOPREFIXROUTE)) {
+ addrconf_prefix_route(&ifp->addr, ifp->prefix_len,
+ idev->dev, 0, 0);
+ }
+
+ addrconf_dad_start(ifp);
+
+ return 0;
+}
+
+static void addrconf_permanent_addr(struct net_device *dev)
+{
+ struct inet6_ifaddr *ifp, *tmp;
+ struct inet6_dev *idev;
+
+ idev = __in6_dev_get(dev);
+ if (!idev)
+ return;
+
+ write_lock_bh(&idev->lock);
+
+ list_for_each_entry_safe(ifp, tmp, &idev->addr_list, if_list) {
+ if ((ifp->flags & IFA_F_PERMANENT) &&
+ fixup_permanent_addr(idev, ifp) < 0) {
+ write_unlock_bh(&idev->lock);
+ ipv6_del_addr(ifp);
+ write_lock_bh(&idev->lock);
+
+ net_info_ratelimited("%s: Failed to add prefix route for address %pI6c; dropping\n",
+ idev->dev->name, &ifp->addr);
+ }
+ }
+
+ write_unlock_bh(&idev->lock);
+}
+
static int addrconf_notify(struct notifier_block *this, unsigned long event,
void *ptr)
{
@@ -3253,6 +3304,9 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
run_pending = 1;
}
+ /* restore routes for permanent addresses */
+ addrconf_permanent_addr(dev);
+
switch (dev->type) {
#if IS_ENABLED(CONFIG_IPV6_SIT)
case ARPHRD_SIT:
@@ -3356,7 +3410,10 @@ static int addrconf_ifdown(struct net_device *dev, int how)
{
struct net *net = dev_net(dev);
struct inet6_dev *idev;
- struct inet6_ifaddr *ifa;
+ struct inet6_ifaddr *ifa, *tmp;
+ struct list_head del_list;
+ int _keep_addr;
+ bool keep_addr;
int state, i;
ASSERT_RTNL();
@@ -3383,6 +3440,16 @@ static int addrconf_ifdown(struct net_device *dev, int how)
}
+ /* aggregate the system setting and interface setting */
+ _keep_addr = net->ipv6.devconf_all->keep_addr_on_down;
+ if (!_keep_addr)
+ _keep_addr = idev->cnf.keep_addr_on_down;
+
+ /* combine the user config with event to determine if permanent
+ * addresses are to be removed from address hash table
+ */
+ keep_addr = !(how || _keep_addr <= 0);
+
/* Step 2: clear hash table */
for (i = 0; i < IN6_ADDR_HSIZE; i++) {
struct hlist_head *h = &inet6_addr_lst[i];
@@ -3391,9 +3458,15 @@ static int addrconf_ifdown(struct net_device *dev, int how)
restart:
hlist_for_each_entry_rcu(ifa, h, addr_lst) {
if (ifa->idev == idev) {
- hlist_del_init_rcu(&ifa->addr_lst);
addrconf_del_dad_work(ifa);
- goto restart;
+ /* combined flag + permanent flag decide if
+ * address is retained on a down event
+ */
+ if (!keep_addr ||
+ !(ifa->flags & IFA_F_PERMANENT)) {
+ hlist_del_init_rcu(&ifa->addr_lst);
+ goto restart;
+ }
}
}
spin_unlock_bh(&addrconf_hash_lock);
@@ -3427,31 +3500,53 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_lock_bh(&idev->lock);
}
- while (!list_empty(&idev->addr_list)) {
- ifa = list_first_entry(&idev->addr_list,
- struct inet6_ifaddr, if_list);
- addrconf_del_dad_work(ifa);
+ /* re-combine the user config with event to determine if permanent
+ * addresses are to be removed from the interface list
+ */
+ keep_addr = (!how && _keep_addr > 0);
- list_del(&ifa->if_list);
+ INIT_LIST_HEAD(&del_list);
+ list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
+ addrconf_del_dad_work(ifa);
write_unlock_bh(&idev->lock);
-
spin_lock_bh(&ifa->lock);
- state = ifa->state;
- ifa->state = INET6_IFADDR_STATE_DEAD;
+
+ if (keep_addr && (ifa->flags & IFA_F_PERMANENT)) {
+ /* set state to skip the notifier below */
+ state = INET6_IFADDR_STATE_DEAD;
+ ifa->state = 0;
+ if (!(ifa->flags & IFA_F_NODAD))
+ ifa->flags |= IFA_F_TENTATIVE;
+ } else {
+ state = ifa->state;
+ ifa->state = INET6_IFADDR_STATE_DEAD;
+
+ list_del(&ifa->if_list);
+ list_add(&ifa->if_list, &del_list);
+ }
+
spin_unlock_bh(&ifa->lock);
if (state != INET6_IFADDR_STATE_DEAD) {
__ipv6_ifa_notify(RTM_DELADDR, ifa);
inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
}
- in6_ifa_put(ifa);
write_lock_bh(&idev->lock);
}
write_unlock_bh(&idev->lock);
+ /* now clean up addresses to be removed */
+ while (!list_empty(&del_list)) {
+ ifa = list_first_entry(&del_list,
+ struct inet6_ifaddr, if_list);
+ list_del(&ifa->if_list);
+
+ in6_ifa_put(ifa);
+ }
+
/* Step 5: Discard anycast and multicast list */
if (how) {
ipv6_ac_destroy_dev(idev);
@@ -4716,6 +4811,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
array[DEVCONF_USE_OIF_ADDRS_ONLY] = cnf->use_oif_addrs_only;
array[DEVCONF_DROP_UNICAST_IN_L2_MULTICAST] = cnf->drop_unicast_in_l2_multicast;
array[DEVCONF_DROP_UNSOLICITED_NA] = cnf->drop_unsolicited_na;
+ array[DEVCONF_KEEP_ADDR_ON_DOWN] = cnf->keep_addr_on_down;
}
static inline size_t inet6_ifla6_size(void)
@@ -5197,10 +5293,12 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
if (rt)
ip6_del_rt(rt);
}
- dst_hold(&ifp->rt->dst);
-
- ip6_del_rt(ifp->rt);
+ if (ifp->rt) {
+ dst_hold(&ifp->rt->dst);
+ ip6_del_rt(ifp->rt);
+ ifp->rt = NULL;
+ }
rt_genid_bump_ipv6(net);
break;
}
@@ -5803,6 +5901,14 @@ static struct addrconf_sysctl_table
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "keep_addr_on_down",
+ .data = &ipv6_devconf.keep_addr_on_down,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+
+ },
{
/* sentinel */
}