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ipv6: Revert optional address flusing on ifdown.
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This reverts the following three commits:

70af921
799977d
f1705ec

The feature was ill conceived, has terrible semantics, and has added
nothing but regressions to the already fragile ipv6 stack.

Fixes: f1705ec ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
davem330 committed Apr 25, 2016
1 parent 391a203 commit 841645b
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Showing 4 changed files with 12 additions and 161 deletions.
9 changes: 0 additions & 9 deletions Documentation/networking/ip-sysctl.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -1568,15 +1568,6 @@ 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
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1 change: 0 additions & 1 deletion include/linux/ipv6.h
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,6 @@ struct ipv6_devconf {
struct in6_addr secret;
} stable_secret;
__s32 use_oif_addrs_only;
__s32 keep_addr_on_down;
void *sysctl;
};

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1 change: 0 additions & 1 deletion include/uapi/linux/ipv6.h
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Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,6 @@ enum {
DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN,
DEVCONF_DROP_UNICAST_IN_L2_MULTICAST,
DEVCONF_DROP_UNSOLICITED_NA,
DEVCONF_KEEP_ADDR_ON_DOWN,
DEVCONF_MAX
};

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162 changes: 12 additions & 150 deletions net/ipv6/addrconf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -216,7 +216,6 @@ 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 = {
Expand Down Expand Up @@ -261,7 +260,6 @@ 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 */
Expand Down Expand Up @@ -3176,81 +3174,6 @@ static void addrconf_gre_config(struct net_device *dev)
}
#endif

#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
/* If the host route is cached on the addr struct make sure it is associated
* with the proper table. e.g., enslavement can change and if so the cached
* host route needs to move to the new table.
*/
static void l3mdev_check_host_rt(struct inet6_dev *idev,
struct inet6_ifaddr *ifp)
{
if (ifp->rt) {
u32 tb_id = l3mdev_fib_table(idev->dev) ? : RT6_TABLE_LOCAL;

if (tb_id != ifp->rt->rt6i_table->tb6_id) {
ip6_del_rt(ifp->rt);
ifp->rt = NULL;
}
}
}
#else
static void l3mdev_check_host_rt(struct inet6_dev *idev,
struct inet6_ifaddr *ifp)
{
}
#endif

static int fixup_permanent_addr(struct inet6_dev *idev,
struct inet6_ifaddr *ifp)
{
l3mdev_check_host_rt(idev, 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)
{
Expand Down Expand Up @@ -3337,9 +3260,6 @@ 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:
Expand Down Expand Up @@ -3448,20 +3368,11 @@ static void addrconf_type_change(struct net_device *dev, unsigned long event)
ipv6_mc_unmap(idev);
}

static bool addr_is_local(const struct in6_addr *addr)
{
return ipv6_addr_type(addr) &
(IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
}

static int addrconf_ifdown(struct net_device *dev, int how)
{
struct net *net = dev_net(dev);
struct inet6_dev *idev;
struct inet6_ifaddr *ifa, *tmp;
struct list_head del_list;
int _keep_addr;
bool keep_addr;
struct inet6_ifaddr *ifa;
int state, i;

ASSERT_RTNL();
Expand All @@ -3488,16 +3399,6 @@ 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];
Expand All @@ -3506,16 +3407,9 @@ 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);
/* combined flag + permanent flag decide if
* address is retained on a down event
*/
if (!keep_addr ||
!(ifa->flags & IFA_F_PERMANENT) ||
addr_is_local(&ifa->addr)) {
hlist_del_init_rcu(&ifa->addr_lst);
goto restart;
}
goto restart;
}
}
spin_unlock_bh(&addrconf_hash_lock);
Expand Down Expand Up @@ -3549,54 +3443,31 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_lock_bh(&idev->lock);
}

/* 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);

INIT_LIST_HEAD(&del_list);
list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
while (!list_empty(&idev->addr_list)) {
ifa = list_first_entry(&idev->addr_list,
struct inet6_ifaddr, if_list);
addrconf_del_dad_work(ifa);

write_unlock_bh(&idev->lock);
spin_lock_bh(&ifa->lock);

if (keep_addr && (ifa->flags & IFA_F_PERMANENT) &&
!addr_is_local(&ifa->addr)) {
/* 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_del(&ifa->if_list);
list_add(&ifa->if_list, &del_list);
}
write_unlock_bh(&idev->lock);

spin_lock_bh(&ifa->lock);
state = ifa->state;
ifa->state = INET6_IFADDR_STATE_DEAD;
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);
Expand Down Expand Up @@ -4861,7 +4732,6 @@ 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)
Expand Down Expand Up @@ -5949,14 +5819,6 @@ 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 */
}
Expand Down

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