ip_tunnel: Ops registration for secondary encap (fou, gue)
Instead of calling fou and gue functions directly from ip_tunnel
use ops for these that were previously registered. This patch adds the
logic to add and remove encapsulation operations for ip_tunnel,
and modified fou (and gue) to register with ip_tunnels.
This patch also addresses a circular dependency between ip_tunnel
and fou that was causing link errors when CONFIG_NET_IP_TUNNEL=y
and CONFIG_NET_FOU=m. References to fou an gue have been removed from
ip_tunnel.c
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/fou.h b/include/net/fou.h
index 25b26ff..19b8a0c 100644
--- a/include/net/fou.h
+++ b/include/net/fou.h
@@ -8,31 +8,12 @@
#include <net/ip_tunnels.h>
#include <net/udp.h>
+size_t fou_encap_hlen(struct ip_tunnel_encap *e);
+static size_t gue_encap_hlen(struct ip_tunnel_encap *e);
+
int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi4 *fl4);
int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi4 *fl4);
-static size_t fou_encap_hlen(struct ip_tunnel_encap *e)
-{
- return sizeof(struct udphdr);
-}
-
-static size_t gue_encap_hlen(struct ip_tunnel_encap *e)
-{
- size_t len;
- bool need_priv = false;
-
- len = sizeof(struct udphdr) + sizeof(struct guehdr);
-
- if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
- len += GUE_PLEN_REMCSUM;
- need_priv = true;
- }
-
- len += need_priv ? GUE_LEN_PRIV : 0;
-
- return len;
-}
-
#endif
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 5bc6ede..25a59eb 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -117,6 +117,22 @@
struct hlist_head tunnels[IP_TNL_HASH_SIZE];
};
+struct ip_tunnel_encap_ops {
+ size_t (*encap_hlen)(struct ip_tunnel_encap *e);
+ int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
+ u8 *protocol, struct flowi4 *fl4);
+};
+
+#define MAX_IPTUN_ENCAP_OPS 8
+
+extern const struct ip_tunnel_encap_ops __rcu *
+ iptun_encaps[MAX_IPTUN_ENCAP_OPS];
+
+int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *op,
+ unsigned int num);
+int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *op,
+ unsigned int num);
+
#ifdef CONFIG_INET
int ip_tunnel_init(struct net_device *dev);
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 740ae09..fe09077 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -668,6 +668,30 @@
},
};
+size_t fou_encap_hlen(struct ip_tunnel_encap *e)
+{
+ return sizeof(struct udphdr);
+}
+EXPORT_SYMBOL(fou_encap_hlen);
+
+size_t gue_encap_hlen(struct ip_tunnel_encap *e)
+{
+ size_t len;
+ bool need_priv = false;
+
+ len = sizeof(struct udphdr) + sizeof(struct guehdr);
+
+ if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
+ len += GUE_PLEN_REMCSUM;
+ need_priv = true;
+ }
+
+ len += need_priv ? GUE_LEN_PRIV : 0;
+
+ return len;
+}
+EXPORT_SYMBOL(gue_encap_hlen);
+
static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
struct flowi4 *fl4, u8 *protocol, __be16 sport)
{
@@ -787,6 +811,57 @@
}
EXPORT_SYMBOL(gue_build_header);
+#ifdef CONFIG_NET_FOU_IP_TUNNELS
+
+static const struct ip_tunnel_encap_ops __read_mostly fou_iptun_ops = {
+ .encap_hlen = fou_encap_hlen,
+ .build_header = fou_build_header,
+};
+
+static const struct ip_tunnel_encap_ops __read_mostly gue_iptun_ops = {
+ .encap_hlen = gue_encap_hlen,
+ .build_header = gue_build_header,
+};
+
+static int ip_tunnel_encap_add_fou_ops(void)
+{
+ int ret;
+
+ ret = ip_tunnel_encap_add_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+ if (ret < 0) {
+ pr_err("can't add fou ops\n");
+ return ret;
+ }
+
+ ret = ip_tunnel_encap_add_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
+ if (ret < 0) {
+ pr_err("can't add gue ops\n");
+ ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void ip_tunnel_encap_del_fou_ops(void)
+{
+ ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+ ip_tunnel_encap_del_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
+}
+
+#else
+
+static int ip_tunnel_encap_add_fou_ops(void)
+{
+ return 0;
+}
+
+static int ip_tunnel_encap_del_fou_ops(void)
+{
+}
+
+#endif
+
static int __init fou_init(void)
{
int ret;
@@ -794,6 +869,14 @@
ret = genl_register_family_with_ops(&fou_nl_family,
fou_nl_ops);
+ if (ret < 0)
+ goto exit;
+
+ ret = ip_tunnel_encap_add_fou_ops();
+ if (ret < 0)
+ genl_unregister_family(&fou_nl_family);
+
+exit:
return ret;
}
@@ -801,6 +884,8 @@
{
struct fou *fou, *next;
+ ip_tunnel_encap_del_fou_ops();
+
genl_unregister_family(&fou_nl_family);
/* Close all the FOU sockets */
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index c3587e1..63e745a 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -57,10 +57,6 @@
#include <net/rtnetlink.h>
#include <net/udp.h>
-#if IS_ENABLED(CONFIG_NET_FOU)
-#include <net/fou.h>
-#endif
-
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/ip6_fib.h>
@@ -494,20 +490,51 @@
static int ip_encap_hlen(struct ip_tunnel_encap *e)
{
- switch (e->type) {
- case TUNNEL_ENCAP_NONE:
+ const struct ip_tunnel_encap_ops *ops;
+ int hlen = -EINVAL;
+
+ if (e->type == TUNNEL_ENCAP_NONE)
return 0;
-#if IS_ENABLED(CONFIG_NET_FOU)
- case TUNNEL_ENCAP_FOU:
- return fou_encap_hlen(e);
- case TUNNEL_ENCAP_GUE:
- return gue_encap_hlen(e);
-#endif
- default:
+
+ if (e->type >= MAX_IPTUN_ENCAP_OPS)
return -EINVAL;
- }
+
+ rcu_read_lock();
+ ops = rcu_dereference(iptun_encaps[e->type]);
+ if (likely(ops && ops->encap_hlen))
+ hlen = ops->encap_hlen(e);
+ rcu_read_unlock();
+
+ return hlen;
}
+const struct ip_tunnel_encap_ops __rcu *
+ iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
+
+int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *ops,
+ unsigned int num)
+{
+ return !cmpxchg((const struct ip_tunnel_encap_ops **)
+ &iptun_encaps[num],
+ NULL, ops) ? 0 : -1;
+}
+EXPORT_SYMBOL(ip_tunnel_encap_add_ops);
+
+int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *ops,
+ unsigned int num)
+{
+ int ret;
+
+ ret = (cmpxchg((const struct ip_tunnel_encap_ops **)
+ &iptun_encaps[num],
+ ops, NULL) == ops) ? 0 : -1;
+
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL(ip_tunnel_encap_del_ops);
+
int ip_tunnel_encap_setup(struct ip_tunnel *t,
struct ip_tunnel_encap *ipencap)
{
@@ -534,18 +561,19 @@
int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
u8 *protocol, struct flowi4 *fl4)
{
- switch (t->encap.type) {
- case TUNNEL_ENCAP_NONE:
+ const struct ip_tunnel_encap_ops *ops;
+ int ret = -EINVAL;
+
+ if (t->encap.type == TUNNEL_ENCAP_NONE)
return 0;
-#if IS_ENABLED(CONFIG_NET_FOU)
- case TUNNEL_ENCAP_FOU:
- return fou_build_header(skb, &t->encap, protocol, fl4);
- case TUNNEL_ENCAP_GUE:
- return gue_build_header(skb, &t->encap, protocol, fl4);
-#endif
- default:
- return -EINVAL;
- }
+
+ rcu_read_lock();
+ ops = rcu_dereference(iptun_encaps[t->encap.type]);
+ if (likely(ops && ops->build_header))
+ ret = ops->build_header(skb, &t->encap, protocol, fl4);
+ rcu_read_unlock();
+
+ return ret;
}
EXPORT_SYMBOL(ip_tunnel_encap);