ipv6: Add a receive path hook for vti6 in xfrm6_mode_tunnel.

Add a receive path hook for the IPsec vritual tunnel interface.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index 4770d515c2c8..cb04f7a16b5e 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -18,6 +18,65 @@
 #include <net/ipv6.h>
 #include <net/xfrm.h>
 
+/* Informational hook. The decap is still done here. */
+static struct xfrm_tunnel_notifier __rcu *rcv_notify_handlers __read_mostly;
+static DEFINE_MUTEX(xfrm6_mode_tunnel_input_mutex);
+
+int xfrm6_mode_tunnel_input_register(struct xfrm_tunnel_notifier *handler)
+{
+        struct xfrm_tunnel_notifier __rcu **pprev;
+        struct xfrm_tunnel_notifier *t;
+        int ret = -EEXIST;
+        int priority = handler->priority;
+
+        mutex_lock(&xfrm6_mode_tunnel_input_mutex);
+
+        for (pprev = &rcv_notify_handlers;
+             (t = rcu_dereference_protected(*pprev,
+             lockdep_is_held(&xfrm6_mode_tunnel_input_mutex))) != NULL;
+             pprev = &t->next) {
+                if (t->priority > priority)
+                        break;
+                if (t->priority == priority)
+                        goto err;
+
+        }
+
+        handler->next = *pprev;
+        rcu_assign_pointer(*pprev, handler);
+
+        ret = 0;
+
+err:
+        mutex_unlock(&xfrm6_mode_tunnel_input_mutex);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(xfrm6_mode_tunnel_input_register);
+
+int xfrm6_mode_tunnel_input_deregister(struct xfrm_tunnel_notifier *handler)
+{
+        struct xfrm_tunnel_notifier __rcu **pprev;
+        struct xfrm_tunnel_notifier *t;
+        int ret = -ENOENT;
+
+        mutex_lock(&xfrm6_mode_tunnel_input_mutex);
+        for (pprev = &rcv_notify_handlers;
+             (t = rcu_dereference_protected(*pprev,
+             lockdep_is_held(&xfrm6_mode_tunnel_input_mutex))) != NULL;
+             pprev = &t->next) {
+                if (t == handler) {
+                        *pprev = handler->next;
+                        ret = 0;
+                        break;
+                }
+        }
+        mutex_unlock(&xfrm6_mode_tunnel_input_mutex);
+        synchronize_net();
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(xfrm6_mode_tunnel_input_deregister);
+
 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
 {
         const struct ipv6hdr *outer_iph = ipv6_hdr(skb);
@@ -63,8 +122,15 @@ static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
         return 0;
 }
 
+#define for_each_input_rcu(head, handler)       \
+        for (handler = rcu_dereference(head);   \
+             handler != NULL;                   \
+             handler = rcu_dereference(handler->next))
+
+
 static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 {
+        struct xfrm_tunnel_notifier *handler;
         int err = -EINVAL;
 
         if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
@@ -72,6 +138,9 @@ static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
                 goto out;
 
+        for_each_input_rcu(rcv_notify_handlers, handler)
+                handler->handler(skb);
+
         err = skb_unclone(skb, GFP_ATOMIC);
         if (err)
                 goto out;