| 
									
										
										
										
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										 |  |  | /*
 | 
					
						
							|  |  |  |  *	Linux INET6 implementation  | 
					
						
							|  |  |  |  * | 
					
						
							|  |  |  |  *	Authors: | 
					
						
							|  |  |  |  *	Pedro Roque		<roque@di.fc.ul.pt>	 | 
					
						
							|  |  |  |  * | 
					
						
							|  |  |  |  *	This program is free software; you can redistribute it and/or | 
					
						
							|  |  |  |  *      modify it under the terms of the GNU General Public License | 
					
						
							|  |  |  |  *      as published by the Free Software Foundation; either version | 
					
						
							|  |  |  |  *      2 of the License, or (at your option) any later version. | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #ifndef _IP6_FIB_H
 | 
					
						
							|  |  |  | #define _IP6_FIB_H
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #ifdef __KERNEL__
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #include <linux/ipv6_route.h>
 | 
					
						
							|  |  |  | #include <linux/rtnetlink.h>
 | 
					
						
							|  |  |  | #include <linux/spinlock.h>
 | 
					
						
							| 
									
										
										
										
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										 |  |  | #include <net/dst.h>
 | 
					
						
							|  |  |  | #include <net/flow.h>
 | 
					
						
							|  |  |  | #include <net/netlink.h>
 | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							|  |  |  | struct rt6_info; | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | struct fib6_config | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	u32		fc_table; | 
					
						
							|  |  |  | 	u32		fc_metric; | 
					
						
							|  |  |  | 	int		fc_dst_len; | 
					
						
							|  |  |  | 	int		fc_src_len; | 
					
						
							|  |  |  | 	int		fc_ifindex; | 
					
						
							|  |  |  | 	u32		fc_flags; | 
					
						
							|  |  |  | 	u32		fc_protocol; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct in6_addr	fc_dst; | 
					
						
							|  |  |  | 	struct in6_addr	fc_src; | 
					
						
							|  |  |  | 	struct in6_addr	fc_gateway; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	unsigned long	fc_expires; | 
					
						
							|  |  |  | 	struct nlattr	*fc_mx; | 
					
						
							|  |  |  | 	int		fc_mx_len; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct nl_info	fc_nlinfo; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct fib6_node | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	struct fib6_node	*parent; | 
					
						
							|  |  |  | 	struct fib6_node	*left; | 
					
						
							|  |  |  | 	struct fib6_node	*right; | 
					
						
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										 |  |  | #ifdef CONFIG_IPV6_SUBTREES
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										 |  |  | 	struct fib6_node	*subtree; | 
					
						
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										 |  |  | #endif
 | 
					
						
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										 |  |  | 	struct rt6_info		*leaf; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	__u16			fn_bit;		/* bit key */ | 
					
						
							|  |  |  | 	__u16			fn_flags; | 
					
						
							|  |  |  | 	__u32			fn_sernum; | 
					
						
							| 
									
										
											  
											
												[IPV6]: Fix routing round-robin locking.
As per RFC2461, section 6.3.6, item #2, when no routers on the
matching list are known to be reachable or probably reachable we
do round robin on those available routes so that we make sure
to probe as many of them as possible to detect when one becomes
reachable faster.
Each routing table has a rwlock protecting the tree and the linked
list of routes at each leaf.  The round robin code executes during
lookup and thus with the rwlock taken as a reader.  A small local
spinlock tries to provide protection but this does not work at all
for two reasons:
1) The round-robin list manipulation, as coded, goes like this (with
   read lock held):
	walk routes finding head and tail
	spin_lock();
	rotate list using head and tail
	spin_unlock();
   While one thread is rotating the list, another thread can
   end up with stale values of head and tail and then proceed
   to corrupt the list when it gets the lock.  This ends up causing
   the OOPS in fib6_add() later onthat many people have been hitting.
2) All the other code paths that run with the rwlock held as
   a reader do not expect the list to change on them, they
   expect it to remain completely fixed while they hold the
   lock in that way.
So, simply stated, it is impossible to implement this correctly using
a manipulation of the list without violating the rwlock locking
semantics.
Reimplement using a per-fib6_node round-robin pointer.  This way we
don't need to manipulate the list at all, and since the round-robin
pointer can only ever point to real existing entries we don't need
to perform any locking on the changing of the round-robin pointer
itself.  We only need to reset the round-robin pointer to NULL when
the entry it is pointing to is removed.
The idea is from Thomas Graf and it is very similar to how this
was implemented before the advanced router selection code when in.
Signed-off-by: David S. Miller <davem@davemloft.net>
											
										 
											2007-03-24 20:36:25 -07:00
										 |  |  | 	struct rt6_info		*rr_ptr; | 
					
						
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										 |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | #ifndef CONFIG_IPV6_SUBTREES
 | 
					
						
							|  |  |  | #define FIB6_SUBTREE(fn)	NULL
 | 
					
						
							|  |  |  | #else
 | 
					
						
							|  |  |  | #define FIB6_SUBTREE(fn)	((fn)->subtree)
 | 
					
						
							|  |  |  | #endif
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										 |  |  | 
 | 
					
						
							|  |  |  | /*
 | 
					
						
							|  |  |  |  *	routing information | 
					
						
							|  |  |  |  * | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | struct rt6key | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	struct in6_addr	addr; | 
					
						
							|  |  |  | 	int		plen; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct fib6_table; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct rt6_info | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	union { | 
					
						
							|  |  |  | 		struct dst_entry	dst; | 
					
						
							|  |  |  | 	} u; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct inet6_dev		*rt6i_idev; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #define rt6i_dev			u.dst.dev
 | 
					
						
							|  |  |  | #define rt6i_nexthop			u.dst.neighbour
 | 
					
						
							|  |  |  | #define rt6i_expires			u.dst.expires
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct fib6_node		*rt6i_node; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct in6_addr			rt6i_gateway; | 
					
						
							|  |  |  | 	 | 
					
						
							|  |  |  | 	u32				rt6i_flags; | 
					
						
							|  |  |  | 	u32				rt6i_metric; | 
					
						
							|  |  |  | 	atomic_t			rt6i_ref; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | 	/* more non-fragment space at head required */ | 
					
						
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										 |  |  | 	unsigned short			rt6i_nfheader_len; | 
					
						
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										 |  |  | 
 | 
					
						
							|  |  |  | 	u8				rt6i_protocol; | 
					
						
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										 |  |  | 
 | 
					
						
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										 |  |  | 	struct fib6_table		*rt6i_table; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 	struct rt6key			rt6i_dst; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | #ifdef CONFIG_XFRM
 | 
					
						
							|  |  |  | 	u32				rt6i_flow_cache_genid; | 
					
						
							|  |  |  | #endif
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										 |  |  | 
 | 
					
						
							|  |  |  | 	struct rt6key			rt6i_src; | 
					
						
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										 |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return ((struct rt6_info *)dst)->rt6i_idev; | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct fib6_walker_t | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	struct fib6_walker_t *prev, *next; | 
					
						
							|  |  |  | 	struct fib6_node *root, *node; | 
					
						
							|  |  |  | 	struct rt6_info *leaf; | 
					
						
							|  |  |  | 	unsigned char state; | 
					
						
							|  |  |  | 	unsigned char prune; | 
					
						
							|  |  |  | 	int (*func)(struct fib6_walker_t *); | 
					
						
							|  |  |  | 	void *args; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | struct rt6_statistics { | 
					
						
							|  |  |  | 	__u32		fib_nodes; | 
					
						
							|  |  |  | 	__u32		fib_route_nodes; | 
					
						
							|  |  |  | 	__u32		fib_rt_alloc;		/* permanent routes	*/ | 
					
						
							|  |  |  | 	__u32		fib_rt_entries;		/* rt entries in table	*/ | 
					
						
							|  |  |  | 	__u32		fib_rt_cache;		/* cache routes		*/ | 
					
						
							|  |  |  | 	__u32		fib_discarded_routes; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #define RTN_TL_ROOT	0x0001
 | 
					
						
							|  |  |  | #define RTN_ROOT	0x0002		/* tree root node		*/
 | 
					
						
							|  |  |  | #define RTN_RTINFO	0x0004		/* node with valid routing info	*/
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | /*
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							|  |  |  |  *	priority levels (or metrics) | 
					
						
							|  |  |  |  * | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct fib6_table { | 
					
						
							|  |  |  | 	struct hlist_node	tb6_hlist; | 
					
						
							|  |  |  | 	u32			tb6_id; | 
					
						
							|  |  |  | 	rwlock_t		tb6_lock; | 
					
						
							|  |  |  | 	struct fib6_node	tb6_root; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #define RT6_TABLE_UNSPEC	RT_TABLE_UNSPEC
 | 
					
						
							|  |  |  | #define RT6_TABLE_MAIN		RT_TABLE_MAIN
 | 
					
						
							|  |  |  | #define RT6_TABLE_DFLT		RT6_TABLE_MAIN
 | 
					
						
							|  |  |  | #define RT6_TABLE_INFO		RT6_TABLE_MAIN
 | 
					
						
							|  |  |  | #define RT6_TABLE_PREFIX	RT6_TABLE_MAIN
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 | 
					
						
							|  |  |  | #define FIB6_TABLE_MIN		1
 | 
					
						
							|  |  |  | #define FIB6_TABLE_MAX		RT_TABLE_MAX
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										 |  |  | #define RT6_TABLE_LOCAL		RT_TABLE_LOCAL
 | 
					
						
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										 |  |  | #else
 | 
					
						
							|  |  |  | #define FIB6_TABLE_MIN		RT_TABLE_MAIN
 | 
					
						
							|  |  |  | #define FIB6_TABLE_MAX		FIB6_TABLE_MIN
 | 
					
						
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										 |  |  | #define RT6_TABLE_LOCAL		RT6_TABLE_MAIN
 | 
					
						
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										 |  |  | #endif
 | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | typedef struct rt6_info *(*pol_lookup_t)(struct net *, | 
					
						
							|  |  |  | 					 struct fib6_table *, | 
					
						
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										 |  |  | 					 struct flowi *, int); | 
					
						
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										 |  |  | 
 | 
					
						
							|  |  |  | /*
 | 
					
						
							|  |  |  |  *	exported functions | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | extern struct fib6_table        *fib6_get_table(struct net *net, u32 id); | 
					
						
							|  |  |  | extern struct fib6_table        *fib6_new_table(struct net *net, u32 id); | 
					
						
							|  |  |  | extern struct dst_entry         *fib6_rule_lookup(struct net *net, | 
					
						
							|  |  |  | 						  struct flowi *fl, int flags, | 
					
						
							|  |  |  | 						  pol_lookup_t lookup); | 
					
						
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										 |  |  | 
 | 
					
						
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										 |  |  | extern struct fib6_node		*fib6_lookup(struct fib6_node *root, | 
					
						
							|  |  |  | 					     struct in6_addr *daddr, | 
					
						
							|  |  |  | 					     struct in6_addr *saddr); | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | struct fib6_node		*fib6_locate(struct fib6_node *root, | 
					
						
							|  |  |  | 					     struct in6_addr *daddr, int dst_len, | 
					
						
							|  |  |  | 					     struct in6_addr *saddr, int src_len); | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | extern void			fib6_clean_all(struct net *net, | 
					
						
							|  |  |  | 					       int (*func)(struct rt6_info *, void *arg), | 
					
						
							| 
									
										
										
										
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										 |  |  | 					       int prune, void *arg); | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | extern int			fib6_add(struct fib6_node *root, | 
					
						
							|  |  |  | 					 struct rt6_info *rt, | 
					
						
							| 
									
										
										
										
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										 |  |  | 					 struct nl_info *info); | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							|  |  |  | extern int			fib6_del(struct rt6_info *rt, | 
					
						
							| 
									
										
										
										
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										 |  |  | 					 struct nl_info *info); | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							|  |  |  | extern void			inet6_rt_notify(int event, struct rt6_info *rt, | 
					
						
							| 
									
										
										
										
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										 |  |  | 						struct nl_info *info); | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2008-03-03 23:28:58 -08:00
										 |  |  | extern void			fib6_run_gc(unsigned long expires, | 
					
						
							|  |  |  | 					    struct net *net); | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							|  |  |  | extern void			fib6_gc_cleanup(void); | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | extern int			fib6_init(void); | 
					
						
							| 
									
										
										
										
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										 |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  | #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 | 
					
						
							| 
									
										
										
										
											2007-12-07 00:42:52 -08:00
										 |  |  | extern int			fib6_rules_init(void); | 
					
						
							| 
									
										
										
										
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										 |  |  | extern void			fib6_rules_cleanup(void); | 
					
						
							| 
									
										
										
										
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										 |  |  | #else
 | 
					
						
							|  |  |  | static inline int               fib6_rules_init(void) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return 0; | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | static inline void              fib6_rules_cleanup(void) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return ; | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | #endif
 | 
					
						
							| 
									
										
										
										
											2005-04-16 15:20:36 -07:00
										 |  |  | #endif
 | 
					
						
							|  |  |  | #endif
 |