linux/include/net/ip6_route.h
Julian Anastasov 96dc809514 ipv6: always prefer rt6i_gateway if present
In v3.9 6fd6ce2056 ("ipv6: Do not depend on rt->n in
ip6_finish_output2()." changed the behaviour of ip6_finish_output2()
such that the recently introduced rt6_nexthop() is used
instead of an assigned neighbor.

As rt6_nexthop() prefers rt6i_gateway only for gatewayed
routes this causes a problem for users like IPVS, xt_TEE and
RAW(hdrincl) if they want to use different address for routing
compared to the destination address.

Another case is when redirect can create RTF_DYNAMIC
route without RTF_GATEWAY flag, we ignore the rt6i_gateway
in rt6_nexthop().

Fix the above problems by considering the rt6i_gateway if
present, so that traffic routed to address on local subnet is
not wrongly diverted to the destination address.

Thanks to Simon Horman and Phil Oester for spotting the
problematic commit.

Thanks to Hannes Frederic Sowa for his review and help in testing.

Reported-by: Phil Oester <kernel@linuxace.com>
Reported-by: Mark Brooks <mark@loadbalancer.org>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-21 18:37:00 -04:00

205 lines
5.6 KiB
C

#ifndef _NET_IP6_ROUTE_H
#define _NET_IP6_ROUTE_H
struct route_info {
__u8 type;
__u8 length;
__u8 prefix_len;
#if defined(__BIG_ENDIAN_BITFIELD)
__u8 reserved_h:3,
route_pref:2,
reserved_l:3;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
__u8 reserved_l:3,
route_pref:2,
reserved_h:3;
#endif
__be32 lifetime;
__u8 prefix[0]; /* 0,8 or 16 */
};
#include <net/flow.h>
#include <net/ip6_fib.h>
#include <net/sock.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/route.h>
#define RT6_LOOKUP_F_IFACE 0x00000001
#define RT6_LOOKUP_F_REACHABLE 0x00000002
#define RT6_LOOKUP_F_HAS_SADDR 0x00000004
#define RT6_LOOKUP_F_SRCPREF_TMP 0x00000008
#define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010
#define RT6_LOOKUP_F_SRCPREF_COA 0x00000020
/*
* rt6_srcprefs2flags() and rt6_flags2srcprefs() translate
* between IPV6_ADDR_PREFERENCES socket option values
* IPV6_PREFER_SRC_TMP = 0x1
* IPV6_PREFER_SRC_PUBLIC = 0x2
* IPV6_PREFER_SRC_COA = 0x4
* and above RT6_LOOKUP_F_SRCPREF_xxx flags.
*/
static inline int rt6_srcprefs2flags(unsigned int srcprefs)
{
/* No need to bitmask because srcprefs have only 3 bits. */
return srcprefs << 3;
}
static inline unsigned int rt6_flags2srcprefs(int flags)
{
return (flags >> 3) & 7;
}
extern void rt6_bind_peer(struct rt6_info *rt, int create);
static inline struct inet_peer *__rt6_get_peer(struct rt6_info *rt, int create)
{
if (rt6_has_peer(rt))
return rt6_peer_ptr(rt);
rt6_bind_peer(rt, create);
return (rt6_has_peer(rt) ? rt6_peer_ptr(rt) : NULL);
}
static inline struct inet_peer *rt6_get_peer(struct rt6_info *rt)
{
return __rt6_get_peer(rt, 0);
}
static inline struct inet_peer *rt6_get_peer_create(struct rt6_info *rt)
{
return __rt6_get_peer(rt, 1);
}
extern void ip6_route_input(struct sk_buff *skb);
extern struct dst_entry * ip6_route_output(struct net *net,
const struct sock *sk,
struct flowi6 *fl6);
extern struct dst_entry * ip6_route_lookup(struct net *net,
struct flowi6 *fl6, int flags);
extern int ip6_route_init(void);
extern void ip6_route_cleanup(void);
extern int ipv6_route_ioctl(struct net *net,
unsigned int cmd,
void __user *arg);
extern int ip6_route_add(struct fib6_config *cfg);
extern int ip6_ins_rt(struct rt6_info *);
extern int ip6_del_rt(struct rt6_info *);
extern int ip6_route_get_saddr(struct net *net,
struct rt6_info *rt,
const struct in6_addr *daddr,
unsigned int prefs,
struct in6_addr *saddr);
extern struct rt6_info *rt6_lookup(struct net *net,
const struct in6_addr *daddr,
const struct in6_addr *saddr,
int oif, int flags);
extern struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
struct flowi6 *fl6);
extern int icmp6_dst_gc(void);
extern void fib6_force_start_gc(struct net *net);
extern struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
const struct in6_addr *addr,
bool anycast);
/*
* support functions for ND
*
*/
extern struct rt6_info * rt6_get_dflt_router(const struct in6_addr *addr,
struct net_device *dev);
extern struct rt6_info * rt6_add_dflt_router(const struct in6_addr *gwaddr,
struct net_device *dev,
unsigned int pref);
extern void rt6_purge_dflt_routers(struct net *net);
extern int rt6_route_rcv(struct net_device *dev,
u8 *opt, int len,
const struct in6_addr *gwaddr);
extern void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
int oif, u32 mark);
extern void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk,
__be32 mtu);
extern void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark);
extern void ip6_redirect_no_header(struct sk_buff *skb, struct net *net, int oif,
u32 mark);
extern void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk);
struct netlink_callback;
struct rt6_rtnl_dump_arg {
struct sk_buff *skb;
struct netlink_callback *cb;
struct net *net;
};
extern int rt6_dump_route(struct rt6_info *rt, void *p_arg);
extern void rt6_ifdown(struct net *net, struct net_device *dev);
extern void rt6_mtu_change(struct net_device *dev, unsigned int mtu);
extern void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
/*
* Store a destination cache entry in a socket
*/
static inline void __ip6_dst_store(struct sock *sk, struct dst_entry *dst,
const struct in6_addr *daddr,
const struct in6_addr *saddr)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct rt6_info *rt = (struct rt6_info *) dst;
sk_setup_caps(sk, dst);
np->daddr_cache = daddr;
#ifdef CONFIG_IPV6_SUBTREES
np->saddr_cache = saddr;
#endif
np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
}
static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
struct in6_addr *daddr, struct in6_addr *saddr)
{
spin_lock(&sk->sk_dst_lock);
__ip6_dst_store(sk, dst, daddr, saddr);
spin_unlock(&sk->sk_dst_lock);
}
static inline bool ipv6_unicast_destination(const struct sk_buff *skb)
{
struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
return rt->rt6i_flags & RTF_LOCAL;
}
int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
{
struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ?
skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
}
static inline struct in6_addr *rt6_nexthop(struct rt6_info *rt, struct in6_addr *dest)
{
if (rt->rt6i_flags & RTF_GATEWAY || !ipv6_addr_any(&rt->rt6i_gateway))
return &rt->rt6i_gateway;
return dest;
}
#endif