compat: Isolate more functions

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 97 insertions, 59 deletions

diff --git a/src/compat.h b/src/compat.h
index 5a49655..29bd8c4 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -6,7 +6,6 @@
 #include <linux/kconfig.h>
 #include <linux/version.h>
 #include <linux/types.h>
-#include <linux/netdevice.h>
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 0)
 #error "WireGuard requires Linux >= 4.1"
@@ -25,17 +24,109 @@
 #define RCU_LOCKDEP_WARN(cond, message) rcu_lockdep_assert(!(cond), message)
 #endif
 
-/* https://lkml.org/lkml/2016/9/28/904
- * 64-bit jiffy functions like in include/linux/jiffies.h */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+#define udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) do { int ret = udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l);  iptunnel_xmit_stats(ret, &dev->stats, dev->tstats); } while (0)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0) && IS_ENABLED(CONFIG_IPV6)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+#define udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, j, k, l)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+struct udp_port_cfg_new {
+	u8 family;
+	union {
+		struct in_addr local_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr local_ip6;
+#endif
+	};
+	union {
+		struct in_addr peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr peer_ip6;
+#endif
+	};
+	__be16 local_udp_port;
+	__be16 peer_udp_port;
+	unsigned int use_udp_checksums:1, use_udp6_tx_checksums:1, use_udp6_rx_checksums:1, ipv6_v6only:1;
+};
+__attribute__((unused)) static inline int udp_sock_create_new(struct net *net, struct udp_port_cfg_new *cfg, struct socket **sockp)
+{
+	struct udp_port_cfg old_cfg = {
+		.family = cfg->family,
+		.local_ip = cfg->local_ip,
+#if IS_ENABLED(CONFIG_IPV6)
+		.local_ip6 = cfg->local_ip6,
+#endif
+		.peer_ip = cfg->peer_ip,
+#if IS_ENABLED(CONFIG_IPV6)
+		.peer_ip6 = cfg->peer_ip6,
+#endif
+		.local_udp_port = cfg->local_udp_port,
+		.peer_udp_port = cfg->peer_udp_port,
+		.use_udp_checksums = cfg->use_udp_checksums,
+		.use_udp6_tx_checksums = cfg->use_udp6_tx_checksums,
+		.use_udp6_rx_checksums = cfg->use_udp6_rx_checksums
+	};
+	if (cfg->family == AF_INET)
+		return udp_sock_create4(net, &old_cfg, sockp);
+
+#if IS_ENABLED(CONFIG_IPV6)
+	if (cfg->family == AF_INET6) {
+		int ret;
+		int old_bindv6only;
+		struct net *nobns;
+
+		if (cfg->ipv6_v6only) {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
+			nobns = &init_net;
+#else
+			nobns = net;
+#endif
+			/* Since udp_port_cfg only learned of ipv6_v6only in 4.3, we do this horrible
+			 * hack here and set the sysctl variable temporarily to something that will
+			 * set the right option for us in sock_create. It's super racey! */
+			old_bindv6only = nobns->ipv6.sysctl.bindv6only;
+			nobns->ipv6.sysctl.bindv6only = 1;
+		}
+		ret = udp_sock_create6(net, &old_cfg, sockp);
+		if (cfg->ipv6_v6only)
+			nobns->ipv6.sysctl.bindv6only = old_bindv6only;
+		return ret;
+	}
+#endif
+	return -EPFNOSUPPORT;
+}
+#define udp_port_cfg udp_port_cfg_new
+#define udp_sock_create(a, b, c) udp_sock_create_new(a, b, c)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
+#define ipv6_dst_lookup(a, b, c, d) ipv6_dst_lookup(b, c, d)
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 5) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)) || LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 17)
+#define IP6_ECN_set_ce(a, b) IP6_ECN_set_ce(b)
+#endif
+
+/* https://lkml.org/lkml/2016/9/28/904 */
 #define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a)
 #define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a)
 #define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a)
 #define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a)
 
-/* https://lkml.org/lkml/2015/6/12/415
- * Inverse of netdev_priv in include/linux/netdevice.h */
+/* https://lkml.org/lkml/2015/6/12/415 */
+#include <linux/netdevice.h>
 static inline struct net_device *netdev_pub(void *dev)
 {
 	return (struct net_device *)((char *)dev - ALIGN(sizeof(struct net_device), NETDEV_ALIGN));
 }
+
 #endif
diff --git a/src/socket.c b/src/socket.c
index 3042f41..fc8863d 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -80,11 +80,7 @@ static inline struct dst_entry *route(struct wireguard_device *wg, struct flowi4
 		/* TODO: addr6->sin6_flowinfo */
 
 		security_sk_classify_flow(sock6, flowi6_to_flowi(fl6));
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
 		ret = ipv6_stub->ipv6_dst_lookup(sock_net(sock6), sock6, &dst, fl6);
-#else
-		ret = ipv6_stub->ipv6_dst_lookup(sock6, &dst, fl6);
-#endif
 		if (unlikely(ret))
 			dst = ERR_PTR(ret);
 #endif
@@ -104,50 +100,24 @@ static inline int send(struct net_device *dev, struct sk_buff *skb, struct dst_e
 			ret = -ENONET;
 			goto err;
 		}
-
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
-		ret = udp_tunnel_xmit_skb((struct rtable *)dst, sock4, skb,
-					  fl4->saddr, fl4->daddr,
-					  dscp, ip4_dst_hoplimit(dst), 0,
-					  fl4->fl4_sport, fl4->fl4_dport,
-					  false, false);
-		iptunnel_xmit_stats(ret, &dev->stats, dev->tstats);
-		return ret > 0 ? 0 : -ECOMM;
-#else
 		udp_tunnel_xmit_skb((struct rtable *)dst, sock4, skb,
 				    fl4->saddr, fl4->daddr,
 				    dscp, ip4_dst_hoplimit(dst), 0,
 				    fl4->fl4_sport, fl4->fl4_dport,
 				    false, false);
 		return 0;
-#endif
 	} else if (addr->ss_family == AF_INET6) {
 		if (unlikely(!sock6)) {
 			ret = -ENONET;
 			goto err;
 		}
 #if IS_ENABLED(CONFIG_IPV6)
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
-		return udp_tunnel6_xmit_skb(dst, sock6, skb, dev,
-					    &fl6->saddr, &fl6->daddr,
-					    dscp, ip6_dst_hoplimit(dst),
-					    fl6->fl6_sport, fl6->fl6_dport,
-					    false) == 0 ? 0 : -ECOMM;
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
-		udp_tunnel6_xmit_skb(dst, sock6, skb, dev,
-				     &fl6->saddr, &fl6->daddr,
-				     dscp, ip6_dst_hoplimit(dst),
-				     fl6->fl6_sport, fl6->fl6_dport,
-				     false);
-		return 0;
-#else
 		udp_tunnel6_xmit_skb(dst, sock6, skb, dev,
 				     &fl6->saddr, &fl6->daddr,
 				     dscp, ip6_dst_hoplimit(dst), 0,
 				     fl6->fl6_sport, fl6->fl6_dport,
 				     false);
 		return 0;
-#endif
 #else
 		goto err;
 #endif
@@ -398,6 +368,7 @@ static inline void set_sock_opts(struct socket *sock)
 
 int socket_init(struct wireguard_device *wg)
 {
+	int ret = 0;
 	struct socket *new4 = NULL;
 	struct udp_port_cfg port4 = {
 		.family = AF_INET,
@@ -411,9 +382,7 @@ int socket_init(struct wireguard_device *wg)
 		.local_ip6 = IN6ADDR_ANY_INIT,
 		.use_udp6_tx_checksums = true,
 		.use_udp6_rx_checksums = true,
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
 		.ipv6_v6only = true
-#endif
 	};
 #endif
 	struct udp_tunnel_sock_cfg cfg = {
@@ -422,12 +391,6 @@ int socket_init(struct wireguard_device *wg)
 		.encap_rcv = receive
 	};
 
-	int ret = 0;
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
-	int old_bindv6only;
-	struct net *nobns;
-#endif
-
 	mutex_lock(&wg->socket_update_lock);
 
 	if (rcu_dereference_protected(wg->sock4, lockdep_is_held(&wg->socket_update_lock)) ||
@@ -455,29 +418,13 @@ int socket_init(struct wireguard_device *wg)
 	rcu_assign_pointer(wg->sock4, new4->sk);
 
 #if IS_ENABLED(CONFIG_IPV6)
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
-	nobns = &init_net;
-#else
-	nobns = wg->creating_net;
-#endif
-	/* Since udp_port_cfg only learned of ipv6_v6only in 4.3, we do this horrible
-	 * hack here and set the sysctl variable temporarily to something that will
-	 * set the right option for us in sock_create. It's super racey! */
-	old_bindv6only = nobns->ipv6.sysctl.bindv6only;
-	nobns->ipv6.sysctl.bindv6only = 1;
-#endif
 	ret = udp_sock_create(wg->creating_net, &port6, &new6);
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
-	nobns->ipv6.sysctl.bindv6only = old_bindv6only;
-#endif
 	if (ret < 0) {
 		pr_err("Could not create IPv6 socket\n");
 		udp_tunnel_sock_release(new4);
 		rcu_assign_pointer(wg->sock4, NULL);
 		goto out;
 	}
-
 	set_sock_opts(new6);
 	setup_udp_tunnel_sock(wg->creating_net, new6, &cfg);
 	rcu_assign_pointer(wg->sock6, new6->sk);