linux/include/net/lwtunnel.h
David Lebrun a23a8f5bc1 lwtunnel: subtract tunnel headroom from mtu on output redirect
This patch changes the lwtunnel_headroom() function which is called
in ipv4_mtu() and ip6_mtu(), to also return the correct headroom
value when the lwtunnel state is OUTPUT_REDIRECT.

This patch enables e.g. SR-IPv6 encapsulations to work without
manually setting the route mtu.

Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-16 17:01:15 -05:00

221 lines
5.1 KiB
C

#ifndef __NET_LWTUNNEL_H
#define __NET_LWTUNNEL_H 1
#include <linux/lwtunnel.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <net/route.h>
#define LWTUNNEL_HASH_BITS 7
#define LWTUNNEL_HASH_SIZE (1 << LWTUNNEL_HASH_BITS)
/* lw tunnel state flags */
#define LWTUNNEL_STATE_OUTPUT_REDIRECT BIT(0)
#define LWTUNNEL_STATE_INPUT_REDIRECT BIT(1)
#define LWTUNNEL_STATE_XMIT_REDIRECT BIT(2)
enum {
LWTUNNEL_XMIT_DONE,
LWTUNNEL_XMIT_CONTINUE,
};
struct lwtunnel_state {
__u16 type;
__u16 flags;
__u16 headroom;
atomic_t refcnt;
int (*orig_output)(struct net *net, struct sock *sk, struct sk_buff *skb);
int (*orig_input)(struct sk_buff *);
struct rcu_head rcu;
__u8 data[0];
};
struct lwtunnel_encap_ops {
int (*build_state)(struct net_device *dev, struct nlattr *encap,
unsigned int family, const void *cfg,
struct lwtunnel_state **ts);
void (*destroy_state)(struct lwtunnel_state *lws);
int (*output)(struct net *net, 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);
int (*cmp_encap)(struct lwtunnel_state *a, struct lwtunnel_state *b);
int (*xmit)(struct sk_buff *skb);
};
#ifdef CONFIG_LWTUNNEL
void lwtstate_free(struct lwtunnel_state *lws);
static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state *lws)
{
if (lws)
atomic_inc(&lws->refcnt);
return lws;
}
static inline void lwtstate_put(struct lwtunnel_state *lws)
{
if (!lws)
return;
if (atomic_dec_and_test(&lws->refcnt))
lwtstate_free(lws);
}
static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
{
if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
return true;
return false;
}
static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
{
if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
return true;
return false;
}
static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
{
if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
return true;
return false;
}
static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
unsigned int mtu)
{
if ((lwtunnel_xmit_redirect(lwtstate) ||
lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
return lwtstate->headroom;
return 0;
}
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,
unsigned int num);
int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
struct nlattr *encap,
unsigned int family, const void *cfg,
struct lwtunnel_state **lws);
int lwtunnel_fill_encap(struct sk_buff *skb,
struct lwtunnel_state *lwtstate);
int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
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 net *net, struct sock *sk, struct sk_buff *skb);
int lwtunnel_input(struct sk_buff *skb);
int lwtunnel_xmit(struct sk_buff *skb);
#else
static inline void lwtstate_free(struct lwtunnel_state *lws)
{
}
static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state *lws)
{
return lws;
}
static inline void lwtstate_put(struct lwtunnel_state *lws)
{
}
static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
{
return false;
}
static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
{
return false;
}
static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
{
return false;
}
static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
unsigned int mtu)
{
return 0;
}
static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
unsigned int num)
{
return -EOPNOTSUPP;
}
static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
unsigned int num)
{
return -EOPNOTSUPP;
}
static inline int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
struct nlattr *encap,
unsigned int family, const void *cfg,
struct lwtunnel_state **lws)
{
return -EOPNOTSUPP;
}
static inline int lwtunnel_fill_encap(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
return 0;
}
static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
{
return 0;
}
static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
{
return NULL;
}
static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
struct lwtunnel_state *b)
{
return 0;
}
static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return -EOPNOTSUPP;
}
static inline int lwtunnel_input(struct sk_buff *skb)
{
return -EOPNOTSUPP;
}
static inline int lwtunnel_xmit(struct sk_buff *skb)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_LWTUNNEL */
#define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
#endif /* __NET_LWTUNNEL_H */