3 files changed, 45 insertions, 18 deletions

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index b4956a5fcc3f..d07b1a64b4e7 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -205,6 +205,7 @@ struct inet6_dev {
 	struct timer_list	rs_timer;
 	__u8			rs_probes;
 
+	__u8			addr_gen_mode;
 	unsigned long		tstamp; /* ipv6InterfaceTable update timestamp */
 	struct rcu_head		rcu;
 };
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index b38534895db5..ff957604a721 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -204,11 +204,17 @@ enum {
 	IFLA_INET6_CACHEINFO,	/* time values and max reasm size */
 	IFLA_INET6_ICMP6STATS,	/* statistics (icmpv6)		*/
 	IFLA_INET6_TOKEN,	/* device token			*/
+	IFLA_INET6_ADDR_GEN_MODE, /* implicit address generator mode */
 	__IFLA_INET6_MAX
 };
 
 #define IFLA_INET6_MAX	(__IFLA_INET6_MAX - 1)
 
+enum in6_addr_gen_mode {
+	IN6_ADDR_GEN_MODE_EUI64,
+	IN6_ADDR_GEN_MODE_NONE,
+};
+
 enum {
 	BRIDGE_MODE_UNSPEC,
 	BRIDGE_MODE_HAIRPIN,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 358edd2272ac..4c03c2843094 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2730,9 +2730,25 @@ static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr
 	}
 }
 
+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;
+
+		ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
+		/* 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);
+		else if (prefix_route)
+			addrconf_prefix_route(&addr, 64, idev->dev, 0, 0);
+	}
+}
+
 static void addrconf_dev_config(struct net_device *dev)
 {
-	struct in6_addr addr;
 	struct inet6_dev *idev;
 
 	ASSERT_RTNL();
@@ -2753,11 +2769,7 @@ static void addrconf_dev_config(struct net_device *dev)
 	if (IS_ERR(idev))
 		return;
 
-	memset(&addr, 0, sizeof(struct in6_addr));
-	addr.s6_addr32[0] = htonl(0xFE800000);
-
-	if (ipv6_generate_eui64(addr.s6_addr + 8, dev) == 0)
-		addrconf_add_linklocal(idev, &addr);
+	addrconf_addr_gen(idev, false);
 }
 
 #if IS_ENABLED(CONFIG_IPV6_SIT)
@@ -2779,11 +2791,7 @@ static void addrconf_sit_config(struct net_device *dev)
 	}
 
 	if (dev->priv_flags & IFF_ISATAP) {
-		struct in6_addr addr;
-
-		ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
-		if (!ipv6_generate_eui64(addr.s6_addr + 8, dev))
-			addrconf_add_linklocal(idev, &addr);
+		addrconf_addr_gen(idev, false);
 		return;
 	}
 
@@ -2798,7 +2806,6 @@ static void addrconf_sit_config(struct net_device *dev)
 static void addrconf_gre_config(struct net_device *dev)
 {
 	struct inet6_dev *idev;
-	struct in6_addr addr;
 
 	ASSERT_RTNL();
 
@@ -2807,11 +2814,7 @@ static void addrconf_gre_config(struct net_device *dev)
 		return;
 	}
 
-	ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
-	if (!ipv6_generate_eui64(addr.s6_addr + 8, dev))
-		addrconf_add_linklocal(idev, &addr);
-	else
-		addrconf_prefix_route(&addr, 64, dev, 0, 0);
+	addrconf_addr_gen(idev, true);
 }
 #endif
 
@@ -4423,6 +4426,10 @@ static int inet6_fill_ifla6_attrs(struct sk_buff *skb, struct inet6_dev *idev)
 	nla = nla_reserve(skb, IFLA_INET6_TOKEN, sizeof(struct in6_addr));
 	if (nla == NULL)
 		goto nla_put_failure;
+
+	if (nla_put_u8(skb, IFLA_INET6_ADDR_GEN_MODE, idev->addr_gen_mode))
+		goto nla_put_failure;
+
 	read_lock_bh(&idev->lock);
 	memcpy(nla_data(nla), idev->token.s6_addr, nla_len(nla));
 	read_unlock_bh(&idev->lock);
@@ -4527,8 +4534,21 @@ static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla)
 	if (nla_parse_nested(tb, IFLA_INET6_MAX, nla, NULL) < 0)
 		BUG();
 
-	if (tb[IFLA_INET6_TOKEN])
+	if (tb[IFLA_INET6_TOKEN]) {
 		err = inet6_set_iftoken(idev, nla_data(tb[IFLA_INET6_TOKEN]));
+		if (err)
+			return err;
+	}
+
+	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)
+			return -EINVAL;
+		idev->addr_gen_mode = mode;
+		err = 0;
+	}
 
 	return err;
 }