[PATCH 1/2] ip/ip6_gre: Fix changing addr gen mode not generating IPv6 link local address

[Thomas Winter]

Commit e5dd729460ca changed the code path so that GRE tunnels
generate an IPv6 address based on the tunnel source address.
It also changed the code path so GRE tunnels don't call addrconf_addr_gen
in addrconf_dev_config which is called by addrconf_sysctl_addr_gen_mode
when the IN6_ADDR_GEN_MODE is changed.

This patch aims to fix this issue by moving the code in addrconf_notify
which calls the addr gen for GRE and SIT into a separate function
and calling it in the places that expect the IPv6 address to be
generated.

The previous addrconf_dev_config is renamed to addrconf_eth_config
since it only expected eth type interfaces and follows the
addrconf_gre/sit_config format.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Thomas Winter <Thomas.Winter@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/addrconf.c | 47 +++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6dcf034835ec..e9d7ec03316d 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3355,7 +3355,7 @@ static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 	}
 }
 
-static void addrconf_dev_config(struct net_device *dev)
+static void addrconf_eth_config(struct net_device *dev)
 {
 	struct inet6_dev *idev;
 
@@ -3447,6 +3447,30 @@ static void addrconf_gre_config(struct net_device *dev)
 }
 #endif
 
+static void addrconf_dev_config(struct net_device *dev)
+{
+	switch (dev->type) {
+#if IS_ENABLED(CONFIG_IPV6_SIT)
+	case ARPHRD_SIT:
+		addrconf_sit_config(dev);
+		break;
+#endif
+#if IS_ENABLED(CONFIG_NET_IPGRE) || IS_ENABLED(CONFIG_IPV6_GRE)
+	case ARPHRD_IP6GRE:
+	case ARPHRD_IPGRE:
+		addrconf_gre_config(dev);
+		break;
+#endif
+	case ARPHRD_LOOPBACK:
+		init_loopback(dev);
+		break;
+
+	default:
+		addrconf_eth_config(dev);
+		break;
+	}
+}
+
 static int fixup_permanent_addr(struct net *net,
 				struct inet6_dev *idev,
 				struct inet6_ifaddr *ifp)
@@ -3611,26 +3635,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
 			run_pending = 1;
 		}
 
-		switch (dev->type) {
-#if IS_ENABLED(CONFIG_IPV6_SIT)
-		case ARPHRD_SIT:
-			addrconf_sit_config(dev);
-			break;
-#endif
-#if IS_ENABLED(CONFIG_NET_IPGRE) || IS_ENABLED(CONFIG_IPV6_GRE)
-		case ARPHRD_IP6GRE:
-		case ARPHRD_IPGRE:
-			addrconf_gre_config(dev);
-			break;
-#endif
-		case ARPHRD_LOOPBACK:
-			init_loopback(dev);
-			break;
-
-		default:
-			addrconf_dev_config(dev);
-			break;
-		}
+		addrconf_dev_config(dev);
 
 		if (!IS_ERR_OR_NULL(idev)) {
 			if (run_pending)
-- 
2.37.3