ipvlan: drop ipv6 dependency

IPVlan has an hard dependency on IPv6, refactor the ipvlan code to allow
compiling it with IPv6 disabled, move duplicate code into addr_equal()
and refactor series of if-else into a switch.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -149,7 +149,6 @@ config MACVTAP
 config IPVLAN
     tristate "IP-VLAN support"
     depends on INET
-    depends on IPV6
     depends on NETFILTER
     depends on NET_L3_MASTER_DEV
     ---help---

drivers/net/ipvlan/ipvlan_core.c

@@ -35,6 +35,7 @@ void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
 }
 EXPORT_SYMBOL_GPL(ipvlan_count_rx);
 
+#if IS_ENABLED(CONFIG_IPV6)
 static u8 ipvlan_get_v6_hash(const void *iaddr)
 {
 	const struct in6_addr *ip6_addr = iaddr;
@@ -42,6 +43,12 @@ static u8 ipvlan_get_v6_hash(const void *iaddr)
 	return __ipv6_addr_jhash(ip6_addr, ipvlan_jhash_secret) &
 	       IPVLAN_HASH_MASK;
 }
+#else
+static u8 ipvlan_get_v6_hash(const void *iaddr)
+{
+	return 0;
+}
+#endif
 
 static u8 ipvlan_get_v4_hash(const void *iaddr)
 {
@@ -51,6 +58,23 @@ static u8 ipvlan_get_v4_hash(const void *iaddr)
 	       IPVLAN_HASH_MASK;
 }
 
+static bool addr_equal(bool is_v6, struct ipvl_addr *addr, const void *iaddr)
+{
+	if (!is_v6 && addr->atype == IPVL_IPV4) {
+		struct in_addr *i4addr = (struct in_addr *)iaddr;
+
+		return addr->ip4addr.s_addr == i4addr->s_addr;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (is_v6 && addr->atype == IPVL_IPV6) {
+		struct in6_addr *i6addr = (struct in6_addr *)iaddr;
+
+		return ipv6_addr_equal(&addr->ip6addr, i6addr);
+#endif
+	}
+
+	return false;
+}
+
 static struct ipvl_addr *ipvlan_ht_addr_lookup(const struct ipvl_port *port,
 					       const void *iaddr, bool is_v6)
 {
@@ -59,15 +83,9 @@ static struct ipvl_addr *ipvlan_ht_addr_lookup(const struct ipvl_port *port,
 
 	hash = is_v6 ? ipvlan_get_v6_hash(iaddr) :
 	       ipvlan_get_v4_hash(iaddr);
-	hlist_for_each_entry_rcu(addr, &port->hlhead[hash], hlnode) {
-		if (is_v6 && addr->atype == IPVL_IPV6 &&
-		    ipv6_addr_equal(&addr->ip6addr, iaddr))
-			return addr;
-		else if (!is_v6 && addr->atype == IPVL_IPV4 &&
-			 addr->ip4addr.s_addr ==
-				((struct in_addr *)iaddr)->s_addr)
+	hlist_for_each_entry_rcu(addr, &port->hlhead[hash], hlnode)
+		if (addr_equal(is_v6, addr, iaddr))
 			return addr;
-	}
 	return NULL;
 }
 
@@ -93,13 +111,9 @@ struct ipvl_addr *ipvlan_find_addr(const struct ipvl_dev *ipvlan,
 {
 	struct ipvl_addr *addr;
 
-	list_for_each_entry(addr, &ipvlan->addrs, anode) {
-		if ((is_v6 && addr->atype == IPVL_IPV6 &&
-		    ipv6_addr_equal(&addr->ip6addr, iaddr)) ||
-		    (!is_v6 && addr->atype == IPVL_IPV4 &&
-		    addr->ip4addr.s_addr == ((struct in_addr *)iaddr)->s_addr))
+	list_for_each_entry(addr, &ipvlan->addrs, anode)
+		if (addr_equal(is_v6, addr, iaddr))
 			return addr;
-	}
 	return NULL;
 }
 
@@ -150,6 +164,7 @@ static void *ipvlan_get_L3_hdr(struct ipvl_port *port, struct sk_buff *skb, int
 		lyr3h = ip4h;
 		break;
 	}
+#if IS_ENABLED(CONFIG_IPV6)
 	case htons(ETH_P_IPV6): {
 		struct ipv6hdr *ip6h;
 
@@ -188,6 +203,7 @@ static void *ipvlan_get_L3_hdr(struct ipvl_port *port, struct sk_buff *skb, int
 		}
 		break;
 	}
+#endif
 	default:
 		return NULL;
 	}
@@ -337,14 +353,18 @@ static struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port,
 {
 	struct ipvl_addr *addr = NULL;
 
-	if (addr_type == IPVL_IPV6) {
+	switch (addr_type) {
+#if IS_ENABLED(CONFIG_IPV6)
+	case IPVL_IPV6: {
 		struct ipv6hdr *ip6h;
 		struct in6_addr *i6addr;
 
 		ip6h = (struct ipv6hdr *)lyr3h;
 		i6addr = use_dest ? &ip6h->daddr : &ip6h->saddr;
 		addr = ipvlan_ht_addr_lookup(port, i6addr, true);
-	} else if (addr_type == IPVL_ICMPV6) {
+		break;
+	}
+	case IPVL_ICMPV6: {
 		struct nd_msg *ndmh;
 		struct in6_addr *i6addr;
 
@@ -356,14 +376,19 @@ static struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port,
 			i6addr = &ndmh->target;
 			addr = ipvlan_ht_addr_lookup(port, i6addr, true);
 		}
-	} else if (addr_type == IPVL_IPV4) {
+		break;
+	}
+#endif
+	case IPVL_IPV4: {
 		struct iphdr *ip4h;
 		__be32 *i4addr;
 
 		ip4h = (struct iphdr *)lyr3h;
 		i4addr = use_dest ? &ip4h->daddr : &ip4h->saddr;
 		addr = ipvlan_ht_addr_lookup(port, i4addr, false);
-	} else if (addr_type == IPVL_ARP) {
+		break;
+	}
+	case IPVL_ARP: {
 		struct arphdr *arph;
 		unsigned char *arp_ptr;
 		__be32 dip;
@@ -377,6 +402,8 @@ static struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port,
 
 		memcpy(&dip, arp_ptr, 4);
 		addr = ipvlan_ht_addr_lookup(port, &dip, false);
+		break;
+	}
 	}
 
 	return addr;
@@ -420,6 +447,7 @@ out:
 	return ret;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
 static int ipvlan_process_v6_outbound(struct sk_buff *skb)
 {
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
@@ -456,6 +484,12 @@ err:
 out:
 	return ret;
 }
+#else
+static int ipvlan_process_v6_outbound(struct sk_buff *skb)
+{
+	return NET_XMIT_DROP;
+}
+#endif
 
 static int ipvlan_process_outbound(struct sk_buff *skb)
 {
@@ -759,6 +793,7 @@ struct sk_buff *ipvlan_l3_rcv(struct net_device *dev, struct sk_buff *skb,
 			goto out;
 		break;
 	}
+#if IS_ENABLED(CONFIG_IPV6)
 	case AF_INET6:
 	{
 		struct dst_entry *dst;
@@ -778,6 +813,7 @@ struct sk_buff *ipvlan_l3_rcv(struct net_device *dev, struct sk_buff *skb,
 		skb_dst_set(skb, dst);
 		break;
 	}
+#endif
 	default:
 		break;
 	}

drivers/net/ipvlan/ipvlan_main.c

@@ -22,12 +22,14 @@ static const struct nf_hook_ops ipvl_nfops[] = {
 		.hooknum  = NF_INET_LOCAL_IN,
 		.priority = INT_MAX,
 	},
+#if IS_ENABLED(CONFIG_IPV6)
 	{
 		.hook     = ipvlan_nf_input,
 		.pf       = NFPROTO_IPV6,
 		.hooknum  = NF_INET_LOCAL_IN,
 		.priority = INT_MAX,
 	},
+#endif
 };
 
 static const struct l3mdev_ops ipvl_l3mdev_ops = {
@@ -800,12 +802,14 @@ static int ipvlan_add_addr(struct ipvl_dev *ipvlan, void *iaddr, bool is_v6)
 		return -ENOMEM;
 
 	addr->master = ipvlan;
-	if (is_v6) {
-		memcpy(&addr->ip6addr, iaddr, sizeof(struct in6_addr));
-		addr->atype = IPVL_IPV6;
-	} else {
+	if (!is_v6) {
 		memcpy(&addr->ip4addr, iaddr, sizeof(struct in_addr));
 		addr->atype = IPVL_IPV4;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else {
+		memcpy(&addr->ip6addr, iaddr, sizeof(struct in6_addr));
+		addr->atype = IPVL_IPV6;
+#endif
 	}
 	list_add_tail(&addr->anode, &ipvlan->addrs);
 
@@ -833,6 +837,20 @@ static void ipvlan_del_addr(struct ipvl_dev *ipvlan, void *iaddr, bool is_v6)
 	return;
 }
 
+static bool ipvlan_is_valid_dev(const struct net_device *dev)
+{
+	struct ipvl_dev *ipvlan = netdev_priv(dev);
+
+	if (!netif_is_ipvlan(dev))
+		return false;
+
+	if (!ipvlan || !ipvlan->port)
+		return false;
+
+	return true;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
 static int ipvlan_add_addr6(struct ipvl_dev *ipvlan, struct in6_addr *ip6_addr)
 {
 	if (ipvlan_addr_busy(ipvlan->port, ip6_addr, true)) {
@@ -850,19 +868,6 @@ static void ipvlan_del_addr6(struct ipvl_dev *ipvlan, struct in6_addr *ip6_addr)
 	return ipvlan_del_addr(ipvlan, ip6_addr, true);
 }
 
-static bool ipvlan_is_valid_dev(const struct net_device *dev)
-{
-	struct ipvl_dev *ipvlan = netdev_priv(dev);
-
-	if (!netif_is_ipvlan(dev))
-		return false;
-
-	if (!ipvlan || !ipvlan->port)
-		return false;
-
-	return true;
-}
-
 static int ipvlan_addr6_event(struct notifier_block *unused,
 			      unsigned long event, void *ptr)
 {
@@ -913,6 +918,7 @@ static int ipvlan_addr6_validator_event(struct notifier_block *unused,
 
 	return NOTIFY_OK;
 }
+#endif
 
 static int ipvlan_add_addr4(struct ipvl_dev *ipvlan, struct in_addr *ip4_addr)
 {
@@ -993,6 +999,7 @@ static struct notifier_block ipvlan_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_device_event,
 };
 
+#if IS_ENABLED(CONFIG_IPV6)
 static struct notifier_block ipvlan_addr6_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_addr6_event,
 };
@@ -1000,6 +1007,7 @@ static struct notifier_block ipvlan_addr6_notifier_block __read_mostly = {
 static struct notifier_block ipvlan_addr6_vtor_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_addr6_validator_event,
 };
+#endif
 
 static void ipvlan_ns_exit(struct net *net)
 {
@@ -1024,9 +1032,11 @@ static int __init ipvlan_init_module(void)
 
 	ipvlan_init_secret();
 	register_netdevice_notifier(&ipvlan_notifier_block);
+#if IS_ENABLED(CONFIG_IPV6)
 	register_inet6addr_notifier(&ipvlan_addr6_notifier_block);
 	register_inet6addr_validator_notifier(
 	    &ipvlan_addr6_vtor_notifier_block);
+#endif
 	register_inetaddr_notifier(&ipvlan_addr4_notifier_block);
 	register_inetaddr_validator_notifier(&ipvlan_addr4_vtor_notifier_block);
 
@@ -1045,9 +1055,11 @@ error:
 	unregister_inetaddr_notifier(&ipvlan_addr4_notifier_block);
 	unregister_inetaddr_validator_notifier(
 	    &ipvlan_addr4_vtor_notifier_block);
+#if IS_ENABLED(CONFIG_IPV6)
 	unregister_inet6addr_notifier(&ipvlan_addr6_notifier_block);
 	unregister_inet6addr_validator_notifier(
 	    &ipvlan_addr6_vtor_notifier_block);
+#endif
 	unregister_netdevice_notifier(&ipvlan_notifier_block);
 	return err;
 }
@@ -1060,9 +1072,11 @@ static void __exit ipvlan_cleanup_module(void)
 	unregister_inetaddr_notifier(&ipvlan_addr4_notifier_block);
 	unregister_inetaddr_validator_notifier(
 	    &ipvlan_addr4_vtor_notifier_block);
+#if IS_ENABLED(CONFIG_IPV6)
 	unregister_inet6addr_notifier(&ipvlan_addr6_notifier_block);
 	unregister_inet6addr_validator_notifier(
 	    &ipvlan_addr6_vtor_notifier_block);
+#endif
 }
 
 module_init(ipvlan_init_module);