Merge branch 'ipv6_stable_privacy_address'

Hannes Frederic Sowa says:

====================
ipv6: RFC7217 stable privacy addresses implementation

this is an implementation of basic support for RFC7217 stable privacy
addresses. Please review and consider for net-next.

v2:
* Correct references to RFC 7212 -> RFC 7217 in documentation patch (thanks, Eric!)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ip-sysctl.txt

@@ -1220,6 +1220,17 @@ anycast_src_echo_reply - BOOLEAN
 	FALSE: disabled
 	Default: FALSE
 
+idgen_delay - INTEGER
+	Controls the delay in seconds after which time to retry
+	privacy stable address generation if a DAD conflict is
+	detected.
+	Default: 1 (as specified in RFC7217)
+
+idgen_retries - INTEGER
+	Controls the number of retries to generate a stable privacy
+	address if a DAD conflict is detected.
+	Default: 3 (as specified in RFC7217)
+
 mld_qrv - INTEGER
 	Controls the MLD query robustness variable (see RFC3810 9.1).
 	Default: 2 (as specified by RFC3810 9.1)
@@ -1540,6 +1551,20 @@ use_optimistic - BOOLEAN
 		0: disabled (default)
 		1: enabled
 
+stable_secret - IPv6 address
+	This IPv6 address will be used as a secret to generate IPv6
+	addresses for link-local addresses and autoconfigured
+	ones. All addresses generated after setting this secret will
+	be stable privacy ones by default. This can be changed via the
+	addrgenmode ip-link. conf/default/stable_secret is used as the
+	secret for the namespace, the interface specific ones can
+	overwrite that. Writes to conf/all/stable_secret are refused.
+
+	It is recommended to generate this secret during installation
+	of a system and keep it stable after that.
+
+	By default the stable secret is unset.
+
 icmp/*:
 ratelimit - INTEGER
 	Limit the maximal rates for sending ICMPv6 packets.

include/linux/ipv6.h

@@ -53,6 +53,10 @@ struct ipv6_devconf {
 	__s32           ndisc_notify;
 	__s32		suppress_frag_ndisc;
 	__s32		accept_ra_mtu;
+	struct ipv6_stable_secret {
+		bool initialized;
+		struct in6_addr secret;
+	} stable_secret;
 	void		*sysctl;
 };
 

include/net/if_inet6.h

@@ -41,18 +41,18 @@ enum {
 struct inet6_ifaddr {
 	struct in6_addr		addr;
 	__u32			prefix_len;
-	
+
 	/* In seconds, relative to tstamp. Expiry is at tstamp + HZ * lft. */
 	__u32			valid_lft;
 	__u32			prefered_lft;
 	atomic_t		refcnt;
 	spinlock_t		lock;
-	spinlock_t		state_lock;
 
 	int			state;
 
 	__u32			flags;
 	__u8			dad_probes;
+	__u8			stable_privacy_retry;
 
 	__u16			scope;
 

include/net/netns/ipv6.h

@@ -32,6 +32,8 @@ struct netns_sysctl_ipv6 {
 	int icmpv6_time;
 	int anycast_src_echo_reply;
 	int fwmark_reflect;
+	int idgen_retries;
+	int idgen_delay;
 };
 
 struct netns_ipv6 {

include/uapi/linux/if_addr.h

@@ -51,6 +51,7 @@ enum {
 #define IFA_F_MANAGETEMPADDR	0x100
 #define IFA_F_NOPREFIXROUTE	0x200
 #define IFA_F_MCAUTOJOIN	0x400
+#define IFA_F_STABLE_PRIVACY	0x800
 
 struct ifa_cacheinfo {
 	__u32	ifa_prefered;

include/uapi/linux/if_link.h

@@ -216,6 +216,7 @@ enum {
 enum in6_addr_gen_mode {
 	IN6_ADDR_GEN_MODE_EUI64,
 	IN6_ADDR_GEN_MODE_NONE,
+	IN6_ADDR_GEN_MODE_STABLE_PRIVACY,
 };
 
 /* Bridge section */

include/uapi/linux/ipv6.h

@@ -170,6 +170,7 @@ enum {
 	DEVCONF_ACCEPT_RA_FROM_LOCAL,
 	DEVCONF_USE_OPTIMISTIC,
 	DEVCONF_ACCEPT_RA_MTU,
+	DEVCONF_STABLE_SECRET,
 	DEVCONF_MAX
 };
 

lib/sha1.c

@@ -198,3 +198,4 @@ void sha_init(__u32 *buf)
 	buf[3] = 0x10325476;
 	buf[4] = 0xc3d2e1f0;
 }
+EXPORT_SYMBOL(sha_init);

net/ipv6/addrconf.c

@@ -46,6 +46,7 @@
 #include <linux/socket.h>
 #include <linux/sockios.h>
 #include <linux/net.h>
+#include <linux/inet.h>
 #include <linux/in6.h>
 #include <linux/netdevice.h>
 #include <linux/if_addr.h>
@@ -102,6 +103,9 @@
 
 #define	INFINITY_LIFE_TIME	0xFFFFFFFF
 
+#define IPV6_MAX_STRLEN \
+	sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")
+
 static inline u32 cstamp_delta(unsigned long cstamp)
 {
 	return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
@@ -127,6 +131,9 @@ static void ipv6_regen_rndid(unsigned long data);
 
 static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
 static int ipv6_count_addresses(struct inet6_dev *idev);
+static int ipv6_generate_stable_address(struct in6_addr *addr,
+					u8 dad_count,
+					const struct inet6_dev *idev);
 
 /*
  *	Configured unicast address hash table
@@ -202,6 +209,9 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.accept_dad		= 1,
 	.suppress_frag_ndisc	= 1,
 	.accept_ra_mtu		= 1,
+	.stable_secret		= {
+		.initialized = false,
+	}
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -240,6 +250,9 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.accept_dad		= 1,
 	.suppress_frag_ndisc	= 1,
 	.accept_ra_mtu		= 1,
+	.stable_secret		= {
+		.initialized = false,
+	},
 };
 
 /* Check if a valid qdisc is available */
@@ -860,7 +873,6 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 		ifa->peer_addr = *peer_addr;
 
 	spin_lock_init(&ifa->lock);
-	spin_lock_init(&ifa->state_lock);
 	INIT_DELAYED_WORK(&ifa->dad_work, addrconf_dad_work);
 	INIT_HLIST_NODE(&ifa->addr_lst);
 	ifa->scope = scope;
@@ -1003,10 +1015,10 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 
 	ASSERT_RTNL();
 
-	spin_lock_bh(&ifp->state_lock);
+	spin_lock_bh(&ifp->lock);
 	state = ifp->state;
 	ifp->state = INET6_IFADDR_STATE_DEAD;
-	spin_unlock_bh(&ifp->state_lock);
+	spin_unlock_bh(&ifp->lock);
 
 	if (state == INET6_IFADDR_STATE_DEAD)
 		goto out;
@@ -1686,19 +1698,21 @@ static int addrconf_dad_end(struct inet6_ifaddr *ifp)
 {
 	int err = -ENOENT;
 
-	spin_lock_bh(&ifp->state_lock);
+	spin_lock_bh(&ifp->lock);
 	if (ifp->state == INET6_IFADDR_STATE_DAD) {
 		ifp->state = INET6_IFADDR_STATE_POSTDAD;
 		err = 0;
 	}
-	spin_unlock_bh(&ifp->state_lock);
+	spin_unlock_bh(&ifp->lock);
 
 	return err;
 }
 
 void addrconf_dad_failure(struct inet6_ifaddr *ifp)
 {
+	struct in6_addr addr;
 	struct inet6_dev *idev = ifp->idev;
+	struct net *net = dev_net(ifp->idev->dev);
 
 	if (addrconf_dad_end(ifp)) {
 		in6_ifa_put(ifp);
@@ -1708,9 +1722,57 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
 	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;
+		int retries = ifp->stable_privacy_retry + 1;
+
+		if (retries > net->ipv6.sysctl.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, net->ipv6.sysctl.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;
 
@@ -1724,10 +1786,10 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
 		}
 	}
 
-	spin_lock_bh(&ifp->state_lock);
+errdad:
 	/* transition from _POSTDAD to _ERRDAD */
 	ifp->state = INET6_IFADDR_STATE_ERRDAD;
-	spin_unlock_bh(&ifp->state_lock);
+	spin_unlock_bh(&ifp->lock);
 
 	addrconf_mod_dad_work(ifp, 0);
 }
@@ -2186,6 +2248,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 	__u32 valid_lft;
 	__u32 prefered_lft;
 	int addr_type;
+	u32 addr_flags = 0;
 	struct inet6_dev *in6_dev;
 	struct net *net = dev_net(dev);
 
@@ -2292,6 +2355,12 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 				       in6_dev->token.s6_addr + 8, 8);
 				read_unlock_bh(&in6_dev->lock);
 				tokenized = true;
+			} else if (in6_dev->addr_gen_mode ==
+				   IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
+				   !ipv6_generate_stable_address(&addr, 0,
+								 in6_dev)) {
+				addr_flags |= IFA_F_STABLE_PRIVACY;
+				goto ok;
 			} else if (ipv6_generate_eui64(addr.s6_addr + 8, dev) &&
 				   ipv6_inherit_eui64(addr.s6_addr + 8, in6_dev)) {
 				in6_dev_put(in6_dev);
@@ -2310,7 +2379,6 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 
 		if (ifp == NULL && valid_lft) {
 			int max_addresses = in6_dev->cnf.max_addresses;
-			u32 addr_flags = 0;
 
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 			if (in6_dev->cnf.optimistic_dad &&
@@ -2350,7 +2418,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 			u32 stored_lft;
 
 			/* update lifetime (RFC2462 5.5.3 e) */
-			spin_lock(&ifp->lock);
+			spin_lock_bh(&ifp->lock);
 			now = jiffies;
 			if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
 				stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
@@ -2380,12 +2448,12 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 				ifp->tstamp = now;
 				flags = ifp->flags;
 				ifp->flags &= ~IFA_F_DEPRECATED;
-				spin_unlock(&ifp->lock);
+				spin_unlock_bh(&ifp->lock);
 
 				if (!(flags&IFA_F_TENTATIVE))
 					ipv6_ifa_notify(0, ifp);
 			} else
-				spin_unlock(&ifp->lock);
+				spin_unlock_bh(&ifp->lock);
 
 			manage_tempaddrs(in6_dev, ifp, valid_lft, prefered_lft,
 					 create, now);
@@ -2789,10 +2857,11 @@ static void init_loopback(struct net_device *dev)
 	}
 }
 
-static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr *addr)
+static void addrconf_add_linklocal(struct inet6_dev *idev,
+				   const struct in6_addr *addr, u32 flags)
 {
 	struct inet6_ifaddr *ifp;
-	u32 addr_flags = IFA_F_PERMANENT;
+	u32 addr_flags = flags | IFA_F_PERMANENT;
 
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	if (idev->cnf.optimistic_dad &&
@@ -2800,7 +2869,6 @@ static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr
 		addr_flags |= IFA_F_OPTIMISTIC;
 #endif
 
-
 	ifp = ipv6_add_addr(idev, addr, NULL, 64, IFA_LINK, addr_flags,
 			    INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
 	if (!IS_ERR(ifp)) {
@@ -2810,18 +2878,103 @@ static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr
 	}
 }
 
+static bool ipv6_reserved_interfaceid(struct in6_addr address)
+{
+	if ((address.s6_addr32[2] | address.s6_addr32[3]) == 0)
+		return true;
+
+	if (address.s6_addr32[2] == htonl(0x02005eff) &&
+	    ((address.s6_addr32[3] & htonl(0xfe000000)) == htonl(0xfe000000)))
+		return true;
+
+	if (address.s6_addr32[2] == htonl(0xfdffffff) &&
+	    ((address.s6_addr32[3] & htonl(0xffffff80)) == htonl(0xffffff80)))
+		return true;
+
+	return false;
+}
+
+static int ipv6_generate_stable_address(struct in6_addr *address,
+					u8 dad_count,
+					const struct inet6_dev *idev)
+{
+	static DEFINE_SPINLOCK(lock);
+	static __u32 digest[SHA_DIGEST_WORDS];
+	static __u32 workspace[SHA_WORKSPACE_WORDS];
+
+	static union {
+		char __data[SHA_MESSAGE_BYTES];
+		struct {
+			struct in6_addr secret;
+			__be64 prefix;
+			unsigned char hwaddr[MAX_ADDR_LEN];
+			u8 dad_count;
+		} __packed;
+	} data;
+
+	struct in6_addr secret;
+	struct in6_addr temp;
+	struct net *net = dev_net(idev->dev);
+
+	BUILD_BUG_ON(sizeof(data.__data) != sizeof(data));
+
+	if (idev->cnf.stable_secret.initialized)
+		secret = idev->cnf.stable_secret.secret;
+	else if (net->ipv6.devconf_dflt->stable_secret.initialized)
+		secret = net->ipv6.devconf_dflt->stable_secret.secret;
+	else
+		return -1;
+
+retry:
+	spin_lock_bh(&lock);
+
+	sha_init(digest);
+	memset(&data, 0, sizeof(data));
+	memset(workspace, 0, sizeof(workspace));
+	memcpy(data.hwaddr, idev->dev->perm_addr, idev->dev->addr_len);
+	data.prefix = ((__be64)address->s6_addr32[0] << 32) |
+		       (__be64)address->s6_addr32[1];
+	data.secret = secret;
+	data.dad_count = dad_count;
+
+	sha_transform(digest, data.__data, workspace);
+
+	temp = *address;
+	temp.s6_addr32[2] = digest[0];
+	temp.s6_addr32[3] = digest[1];
+
+	spin_unlock_bh(&lock);
+
+	if (ipv6_reserved_interfaceid(temp)) {
+		dad_count++;
+		if (dad_count > dev_net(idev->dev)->ipv6.sysctl.idgen_retries)
+			return -1;
+		goto retry;
+	}
+
+	*address = temp;
+	return 0;
+}
+
 static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 {
-	if (idev->addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64) {
-		struct in6_addr addr;
+	struct in6_addr addr;
 
-		ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
+	ipv6_addr_set(&addr, htonl(0xFE800000), 0, 0, 0);
+
+	if (idev->addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY) {
+		if (!ipv6_generate_stable_address(&addr, 0, idev))
+			addrconf_add_linklocal(idev, &addr,
+					       IFA_F_STABLE_PRIVACY);
+		else if (prefix_route)
+			addrconf_prefix_route(&addr, 64, idev->dev, 0, 0);
+	} else if (idev->addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64) {
 		/* addrconf_add_linklocal also adds a prefix_route and we
 		 * only need to care about prefix routes if ipv6_generate_eui64
 		 * couldn't generate one.
 		 */
 		if (ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) == 0)
-			addrconf_add_linklocal(idev, &addr);
+			addrconf_add_linklocal(idev, &addr, 0);
 		else if (prefix_route)
 			addrconf_prefix_route(&addr, 64, idev->dev, 0, 0);
 	}
@@ -3159,10 +3312,10 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 
 		write_unlock_bh(&idev->lock);
 
-		spin_lock_bh(&ifa->state_lock);
+		spin_lock_bh(&ifa->lock);
 		state = ifa->state;
 		ifa->state = INET6_IFADDR_STATE_DEAD;
-		spin_unlock_bh(&ifa->state_lock);
+		spin_unlock_bh(&ifa->lock);
 
 		if (state != INET6_IFADDR_STATE_DEAD) {
 			__ipv6_ifa_notify(RTM_DELADDR, ifa);
@@ -3320,12 +3473,12 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp)
 {
 	bool begin_dad = false;
 
-	spin_lock_bh(&ifp->state_lock);
+	spin_lock_bh(&ifp->lock);
 	if (ifp->state != INET6_IFADDR_STATE_DEAD) {
 		ifp->state = INET6_IFADDR_STATE_PREDAD;
 		begin_dad = true;
 	}
-	spin_unlock_bh(&ifp->state_lock);
+	spin_unlock_bh(&ifp->lock);
 
 	if (begin_dad)
 		addrconf_mod_dad_work(ifp, 0);
@@ -3347,7 +3500,7 @@ static void addrconf_dad_work(struct work_struct *w)
 
 	rtnl_lock();
 
-	spin_lock_bh(&ifp->state_lock);
+	spin_lock_bh(&ifp->lock);
 	if (ifp->state == INET6_IFADDR_STATE_PREDAD) {
 		action = DAD_BEGIN;
 		ifp->state = INET6_IFADDR_STATE_DAD;
@@ -3355,7 +3508,7 @@ static void addrconf_dad_work(struct work_struct *w)
 		action = DAD_ABORT;
 		ifp->state = INET6_IFADDR_STATE_POSTDAD;
 	}
-	spin_unlock_bh(&ifp->state_lock);
+	spin_unlock_bh(&ifp->lock);
 
 	if (action == DAD_BEGIN) {
 		addrconf_dad_begin(ifp);
@@ -4430,6 +4583,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
 	array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
 	array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu;
+	/* we omit DEVCONF_STABLE_SECRET for now */
 }
 
 static inline size_t inet6_ifla6_size(void)
@@ -4664,8 +4818,15 @@ static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla)
 		u8 mode = nla_get_u8(tb[IFLA_INET6_ADDR_GEN_MODE]);
 
 		if (mode != IN6_ADDR_GEN_MODE_EUI64 &&
-		    mode != IN6_ADDR_GEN_MODE_NONE)
+		    mode != IN6_ADDR_GEN_MODE_NONE &&
+		    mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY)
 			return -EINVAL;
+
+		if (mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
+		    !idev->cnf.stable_secret.initialized &&
+		    !dev_net(dev)->ipv6.devconf_dflt->stable_secret.initialized)
+			return -EINVAL;
+
 		idev->addr_gen_mode = mode;
 		err = 0;
 	}
@@ -5074,6 +5235,74 @@ int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
+					 void __user *buffer, size_t *lenp,
+					 loff_t *ppos)
+{
+	int err;
+	struct in6_addr addr;
+	char str[IPV6_MAX_STRLEN];
+	struct ctl_table lctl = *ctl;
+	struct net *net = ctl->extra2;
+	struct ipv6_stable_secret *secret = ctl->data;
+
+	if (&net->ipv6.devconf_all->stable_secret == ctl->data)
+		return -EIO;
+
+	lctl.maxlen = IPV6_MAX_STRLEN;
+	lctl.data = str;
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	if (!write && !secret->initialized) {
+		err = -EIO;
+		goto out;
+	}
+
+	if (!write) {
+		err = snprintf(str, sizeof(str), "%pI6",
+			       &secret->secret);
+		if (err >= sizeof(str)) {
+			err = -EIO;
+			goto out;
+		}
+	}
+
+	err = proc_dostring(&lctl, write, buffer, lenp, ppos);
+	if (err || !write)
+		goto out;
+
+	if (in6_pton(str, -1, addr.in6_u.u6_addr8, -1, NULL) != 1) {
+		err = -EIO;
+		goto out;
+	}
+
+	secret->initialized = true;
+	secret->secret = addr;
+
+	if (&net->ipv6.devconf_dflt->stable_secret == ctl->data) {
+		struct net_device *dev;
+
+		for_each_netdev(net, dev) {
+			struct inet6_dev *idev = __in6_dev_get(dev);
+
+			if (idev) {
+				idev->addr_gen_mode =
+					IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
+			}
+		}
+	} else {
+		struct inet6_dev *idev = ctl->extra1;
+
+		idev->addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
+	}
+
+out:
+	rtnl_unlock();
+
+	return err;
+}
 
 static struct addrconf_sysctl_table
 {
@@ -5346,6 +5575,13 @@ static struct addrconf_sysctl_table
 			.mode		= 0644,
 			.proc_handler	= proc_dointvec,
 		},
+		{
+			.procname	= "stable_secret",
+			.data		= &ipv6_devconf.stable_secret,
+			.maxlen		= IPV6_MAX_STRLEN,
+			.mode		= 0600,
+			.proc_handler	= addrconf_sysctl_stable_secret,
+		},
 		{
 			/* sentinel */
 		}
@@ -5442,6 +5678,9 @@ static int __net_init addrconf_init_net(struct net *net)
 	dflt->autoconf = ipv6_defaults.autoconf;
 	dflt->disable_ipv6 = ipv6_defaults.disable_ipv6;
 
+	dflt->stable_secret.initialized = false;
+	all->stable_secret.initialized = false;
+
 	net->ipv6.devconf_all = all;
 	net->ipv6.devconf_dflt = dflt;
 

net/ipv6/af_inet6.c

@@ -766,6 +766,8 @@ static int __net_init inet6_net_init(struct net *net)
 	net->ipv6.sysctl.icmpv6_time = 1*HZ;
 	net->ipv6.sysctl.flowlabel_consistency = 1;
 	net->ipv6.sysctl.auto_flowlabels = 0;
+	net->ipv6.sysctl.idgen_retries = 3;
+	net->ipv6.sysctl.idgen_delay = 1 * HZ;
 	atomic_set(&net->ipv6.fib6_sernum, 1);
 
 	err = ipv6_init_mibs(net);

net/ipv6/sysctl_net_ipv6.c

@@ -54,6 +54,20 @@ static struct ctl_table ipv6_table_template[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "idgen_retries",
+		.data		= &init_net.ipv6.sysctl.idgen_retries,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "idgen_delay",
+		.data		= &init_net.ipv6.sysctl.idgen_delay,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
 	{ }
 };
 
@@ -93,6 +107,8 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
 	ipv6_table[2].data = &net->ipv6.sysctl.flowlabel_consistency;
 	ipv6_table[3].data = &net->ipv6.sysctl.auto_flowlabels;
 	ipv6_table[4].data = &net->ipv6.sysctl.fwmark_reflect;
+	ipv6_table[5].data = &net->ipv6.sysctl.idgen_retries;
+	ipv6_table[6].data = &net->ipv6.sysctl.idgen_delay;
 
 	ipv6_route_table = ipv6_route_sysctl_init(net);
 	if (!ipv6_route_table)