[PATCH v4 net-next 1/2] net/ipv6: allow sysctl to change link-local address generation mode

@@ -69,6 +69,7 @@ struct ipv6_devconf {
 	__s32		seg6_require_hmac;
 #endif
 	__u32		enhanced_dad;
+	__u32		addr_gen_mode;
 
 	struct ctl_table_header *sysctl_header;
 };

@@ -205,7 +205,6 @@ struct inet6_dev {
 	__s32			rs_interval;	/* in jiffies */
 	__u8			rs_probes;
 
-	__u8			addr_gen_mode;
 	unsigned long		tstamp; /* ipv6InterfaceTable update timestamp */
 	struct rcu_head		rcu;
 };

@@ -182,6 +182,7 @@ enum {
 	DEVCONF_SEG6_ENABLED,
 	DEVCONF_SEG6_REQUIRE_HMAC,
 	DEVCONF_ENHANCED_DAD,
+	DEVCONF_ADDR_GEN_MODE,
 	DEVCONF_MAX
 };
 

@@ -243,6 +243,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.seg6_require_hmac	= 0,
 #endif
 	.enhanced_dad           = 1,
+	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {

@@ -294,6 +295,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.seg6_require_hmac	= 0,
 #endif
 	.enhanced_dad           = 1,
+	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 };
 
 /* Check if a valid qdisc is available */

@@ -386,9 +388,9 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
 	memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));
 
 	if (ndev->cnf.stable_secret.initialized)
-		ndev->addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
+		ndev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
 	else
-		ndev->addr_gen_mode = IN6_ADDR_GEN_MODE_EUI64;
+		ndev->cnf.addr_gen_mode = ipv6_devconf_dflt.addr_gen_mode;
 
 	ndev->cnf.mtu6 = dev->mtu;
 	ndev->nd_parms = neigh_parms_alloc(dev, &nd_tbl);

@@ -2387,8 +2389,8 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 
 static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
 {
-	return idev->addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY ||
-	       idev->addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
+	return idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY ||
+	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
 }
 
 int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,

@@ -3152,7 +3154,7 @@ static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 
 	ipv6_addr_set(&addr, htonl(0xFE800000), 0, 0, 0);
 
-	switch (idev->addr_gen_mode) {
+	switch (idev->cnf.addr_gen_mode) {
 	case IN6_ADDR_GEN_MODE_RANDOM:
 		ipv6_gen_mode_random_init(idev);
 		/* fallthrough */

@@ -3204,8 +3206,8 @@ static void addrconf_dev_config(struct net_device *dev)
 
 	/* this device type has no EUI support */
 	if (dev->type == ARPHRD_NONE &&
-	    idev->addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64)
-		idev->addr_gen_mode = IN6_ADDR_GEN_MODE_RANDOM;
+	    idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64)
+		idev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_RANDOM;
 
 	addrconf_addr_gen(idev, false);
 }

@@ -4982,6 +4984,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_SEG6_REQUIRE_HMAC] = cnf->seg6_require_hmac;
 #endif
 	array[DEVCONF_ENHANCED_DAD] = cnf->enhanced_dad;
+	array[DEVCONF_ADDR_GEN_MODE] = cnf->addr_gen_mode;
 }
 
 static inline size_t inet6_ifla6_size(void)

@@ -5093,7 +5096,7 @@ static int inet6_fill_ifla6_attrs(struct sk_buff *skb, struct inet6_dev *idev,
 	if (!nla)
 		goto nla_put_failure;
 
-	if (nla_put_u8(skb, IFLA_INET6_ADDR_GEN_MODE, idev->addr_gen_mode))
+	if (nla_put_u8(skb, IFLA_INET6_ADDR_GEN_MODE, idev->cnf.addr_gen_mode))
 		goto nla_put_failure;
 
 	read_lock_bh(&idev->lock);

@@ -5211,6 +5214,26 @@ static int inet6_validate_link_af(const struct net_device *dev,
 	return nla_parse_nested(tb, IFLA_INET6_MAX, nla, inet6_af_policy);
 }
 
+static int check_addr_gen_mode(int mode)
+{
+	if (mode != IN6_ADDR_GEN_MODE_EUI64 &&
+	    mode != IN6_ADDR_GEN_MODE_NONE &&
+	    mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
+	    mode != IN6_ADDR_GEN_MODE_RANDOM)
+		return -EINVAL;
+	return 1;
+}
+
+static int check_stable_privacy(struct inet6_dev *idev, struct net *net,
+				int mode)
+{
+	if (mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
+	    !idev->cnf.stable_secret.initialized &&
+	    !net->ipv6.devconf_dflt->stable_secret.initialized)
+		return -EINVAL;
+	return 1;
+}
+
 static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla)
 {
 	int err = -EINVAL;

@@ -5232,18 +5255,11 @@ static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla)
 	if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
 		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_STABLE_PRIVACY &&
-		    mode != IN6_ADDR_GEN_MODE_RANDOM)
-			return -EINVAL;
-
-		if (mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
-		    !idev->cnf.stable_secret.initialized &&
-		    !dev_net(dev)->ipv6.devconf_dflt->stable_secret.initialized)
+		if (check_addr_gen_mode(mode) < 0 ||
+		    check_stable_privacy(idev, dev_net(dev), mode) < 0)
 			return -EINVAL;
 
-		idev->addr_gen_mode = mode;
+		idev->cnf.addr_gen_mode = mode;
 		err = 0;
 	}
 

@@ -5652,6 +5668,47 @@ int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
+					 void __user *buffer, size_t *lenp,
+					 loff_t *ppos)
+{
+	int ret = 0;
+	int new_val;
+	struct inet6_dev *idev = (struct inet6_dev *)ctl->extra1;
+	struct net *net = (struct net *)ctl->extra2;
+
+	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+
+	if (write) {
+		new_val = *((int *)ctl->data);
+
+		if (check_addr_gen_mode(new_val) < 0)
+			return -EINVAL;
+
+		/* request for default */
+		if (&net->ipv6.devconf_dflt->addr_gen_mode == ctl->data) {
+			ipv6_devconf_dflt.addr_gen_mode = new_val;
+
+		/* request for individual net device */
+		} else {
+			if (!idev)
+				return ret;
+
+			if (check_stable_privacy(idev, net, new_val) < 0)
+				return -EINVAL;
+
+			if (idev->cnf.addr_gen_mode != new_val) {
+				idev->cnf.addr_gen_mode = new_val;
+				rtnl_lock();
+				addrconf_dev_config(idev->dev);
+				rtnl_unlock();
+			}
+		}
+	}
+
+	return ret;
+}
+
 static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
 					 void __user *buffer, size_t *lenp,
 					 loff_t *ppos)

@@ -5702,14 +5759,14 @@ static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
 			struct inet6_dev *idev = __in6_dev_get(dev);
 
 			if (idev) {
-				idev->addr_gen_mode =
+				idev->cnf.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;
+		idev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
 	}
 
 out:

@@ -6097,6 +6154,13 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.proc_handler   = proc_dointvec,
 	},
 	{
+		.procname		= "addr_gen_mode",
+		.data			= &ipv6_devconf.addr_gen_mode,
+		.maxlen			= sizeof(int),
+		.mode			= 0644,
+		.proc_handler	= addrconf_sysctl_addr_gen_mode,
+	},
+	{
 		/* sentinel */
 	}
 };

@@ -2146,12 +2146,14 @@ static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
 	case ARPHRD_SIT:
 		return addrconf_ifid_sit(eui, dev);
 	case ARPHRD_IPGRE:
+	case ARPHRD_TUNNEL:
 		return addrconf_ifid_gre(eui, dev);
 	case ARPHRD_6LOWPAN:
 		return addrconf_ifid_eui64(eui, dev);
 	case ARPHRD_IEEE1394:
 		return addrconf_ifid_ieee1394(eui, dev);
 	case ARPHRD_TUNNEL6:
+	case ARPHRD_IP6GRE:
 		return addrconf_ifid_ip6tnl(eui, dev);
 	}
 	return -1;

@@ -3195,6 +3197,9 @@ static void addrconf_dev_config(struct net_device *dev)
 	    (dev->type != ARPHRD_IEEE1394) &&
 	    (dev->type != ARPHRD_TUNNEL6) &&
 	    (dev->type != ARPHRD_6LOWPAN) &&
+	    (dev->type != ARPHRD_IP6GRE) &&
+	    (dev->type != ARPHRD_IPGRE) &&
+	    (dev->type != ARPHRD_TUNNEL) &&
 	    (dev->type != ARPHRD_NONE)) {
 		/* Alas, we support only Ethernet autoconfiguration. */
 		return;

@@ -993,6 +993,9 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
 	dev->flags |= IFF_NOARP;
 	dev->addr_len = sizeof(struct in6_addr);
 	netif_keep_dst(dev);
+	/* This perm addr will be used as interface identifier by IPv6 */
+	dev->addr_assign_type = NET_ADDR_RANDOM;
+	eth_random_addr(dev->perm_addr);
 }
 
 static int ip6gre_tunnel_init_common(struct net_device *dev)

@@ -49,6 +49,7 @@
 #include <net/xfrm.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
+#include <linux/etherdevice.h>
 
 #define IP6_VTI_HASH_SIZE_SHIFT  5
 #define IP6_VTI_HASH_SIZE (1 << IP6_VTI_HASH_SIZE_SHIFT)

@@ -842,6 +843,9 @@ static void vti6_dev_setup(struct net_device *dev)
 	dev->flags |= IFF_NOARP;
 	dev->addr_len = sizeof(struct in6_addr);
 	netif_keep_dst(dev);
+	/* This perm addr will be used as interface identifier by IPv6 */
+	dev->addr_assign_type = NET_ADDR_RANDOM;
+	eth_random_addr(dev->perm_addr);
 }
 
 /**