I will send out a v2 short, this breaks compilation when
CONFIG_LWTUNNEL is not defined.
On Thu, Aug 13, 2015 at 9:54 AM, Tom Herbert <t...@herbertland.com> wrote:
> 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 <t...@herbertland.com>
> ---
> include/net/lwtunnel.h | 25 ++++++++++++++++++++++-
> net/core/lwtunnel.c | 55
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> net/ipv4/route.c | 8 +++++++-
> net/ipv6/route.c | 8 +++++++-
> 4 files changed, 93 insertions(+), 3 deletions(-)
>
> diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
> index 33bd309..3db87d7 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 @@ struct lwtunnel_encap_ops {
> 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 @@ static inline bool lwtunnel_output_redirect(struct
> lwtunnel_state *lwtstate)
> 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 @@ struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
> 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
>
> @@ -142,6 +155,16 @@ static inline int lwtunnel_output6(struct sock *sk,
> struct sk_buff *skb)
> return -EOPNOTSUPP;
> }
>
> +static inline int lwtunnel_input(struct sock *sk, struct sk_buff *skb)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static inline int lwtunnel_input6(struct sock *sk, 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 @@ int lwtunnel_output(struct sock *sk, struct sk_buff *skb)
> 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 18fd7c9..051d834 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1630,8 +1630,14 @@ static int __mkroute_input(struct sk_buff *skb,
> 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 54fccf0..b01a437 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -1779,8 +1779,14 @@ int ip6_route_add(struct fib6_config *cfg)
> 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);
> --
> 1.8.1
>
> --
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