lwt: Add support to redirect dst.input
This patch adds the capability to redirect dst input in the same way
that dst output is redirected by LWT.
Also, save the original dst.input and and dst.out when setting up
lwtunnel redirection. These can be called by the client as a pass-
through.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
index 33bd309..e25b60e 100644
--- a/include/net/lwtunnel.h
+++ b/include/net/lwtunnel.h
@@ -11,12 +11,15 @@
#define LWTUNNEL_HASH_SIZE (1 << LWTUNNEL_HASH_BITS)
/* lw tunnel state flags */
-#define LWTUNNEL_STATE_OUTPUT_REDIRECT 0x1
+#define LWTUNNEL_STATE_OUTPUT_REDIRECT BIT(0)
+#define LWTUNNEL_STATE_INPUT_REDIRECT BIT(1)
struct lwtunnel_state {
__u16 type;
__u16 flags;
atomic_t refcnt;
+ int (*orig_output)(struct sock *sk, struct sk_buff *skb);
+ int (*orig_input)(struct sk_buff *);
int len;
__u8 data[0];
};
@@ -25,6 +28,7 @@
int (*build_state)(struct net_device *dev, struct nlattr *encap,
struct lwtunnel_state **ts);
int (*output)(struct sock *sk, struct sk_buff *skb);
+ int (*input)(struct sk_buff *skb);
int (*fill_encap)(struct sk_buff *skb,
struct lwtunnel_state *lwtstate);
int (*get_encap_size)(struct lwtunnel_state *lwtstate);
@@ -58,6 +62,13 @@
return false;
}
+static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
+{
+ if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
+ return true;
+
+ return false;
+}
int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
unsigned int num);
int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
@@ -72,6 +83,8 @@
int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
int lwtunnel_output(struct sock *sk, struct sk_buff *skb);
int lwtunnel_output6(struct sock *sk, struct sk_buff *skb);
+int lwtunnel_input(struct sk_buff *skb);
+int lwtunnel_input6(struct sk_buff *skb);
#else
@@ -90,6 +103,11 @@
return false;
}
+static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
+{
+ return false;
+}
+
static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
unsigned int num)
{
@@ -142,6 +160,16 @@
return -EOPNOTSUPP;
}
+static inline int lwtunnel_input(struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int lwtunnel_input6(struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
#endif
#endif /* __NET_LWTUNNEL_H */
diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
index 5d6d8e3..3331585 100644
--- a/net/core/lwtunnel.c
+++ b/net/core/lwtunnel.c
@@ -241,3 +241,58 @@
return __lwtunnel_output(sk, skb, lwtstate);
}
EXPORT_SYMBOL(lwtunnel_output);
+
+int __lwtunnel_input(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate)
+{
+ const struct lwtunnel_encap_ops *ops;
+ int ret = -EINVAL;
+
+ if (!lwtstate)
+ goto drop;
+
+ if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
+ lwtstate->type > LWTUNNEL_ENCAP_MAX)
+ return 0;
+
+ ret = -EOPNOTSUPP;
+ rcu_read_lock();
+ ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
+ if (likely(ops && ops->input))
+ ret = ops->input(skb);
+ rcu_read_unlock();
+
+ if (ret == -EOPNOTSUPP)
+ goto drop;
+
+ return ret;
+
+drop:
+ kfree_skb(skb);
+
+ return ret;
+}
+
+int lwtunnel_input6(struct sk_buff *skb)
+{
+ struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
+ struct lwtunnel_state *lwtstate = NULL;
+
+ if (rt)
+ lwtstate = rt->rt6i_lwtstate;
+
+ return __lwtunnel_input(skb, lwtstate);
+}
+EXPORT_SYMBOL(lwtunnel_input6);
+
+int lwtunnel_input(struct sk_buff *skb)
+{
+ struct rtable *rt = (struct rtable *)skb_dst(skb);
+ struct lwtunnel_state *lwtstate = NULL;
+
+ if (rt)
+ lwtstate = rt->rt_lwtstate;
+
+ return __lwtunnel_input(skb, lwtstate);
+}
+EXPORT_SYMBOL(lwtunnel_input);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 2c89d29..2403e85 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1631,8 +1631,14 @@
rth->dst.output = ip_output;
rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
- if (lwtunnel_output_redirect(rth->rt_lwtstate))
+ if (lwtunnel_output_redirect(rth->rt_lwtstate)) {
+ rth->rt_lwtstate->orig_output = rth->dst.output;
rth->dst.output = lwtunnel_output;
+ }
+ if (lwtunnel_input_redirect(rth->rt_lwtstate)) {
+ rth->rt_lwtstate->orig_input = rth->dst.input;
+ rth->dst.input = lwtunnel_input;
+ }
skb_dst_set(skb, &rth->dst);
out:
err = 0;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1c0217e..c373304 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1785,8 +1785,14 @@
if (err)
goto out;
rt->rt6i_lwtstate = lwtstate_get(lwtstate);
- if (lwtunnel_output_redirect(rt->rt6i_lwtstate))
+ if (lwtunnel_output_redirect(rt->rt6i_lwtstate)) {
+ rt->rt6i_lwtstate->orig_output = rt->dst.output;
rt->dst.output = lwtunnel_output6;
+ }
+ if (lwtunnel_input_redirect(rt->rt6i_lwtstate)) {
+ rt->rt6i_lwtstate->orig_input = rt->dst.input;
+ rt->dst.input = lwtunnel_input6;
+ }
}
ipv6_addr_prefix(&rt->rt6i_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);