linux/include/net/ip6_fib.h
David Ahern 0ae8133586 net: ipv6: Allow shorthand delete of all nexthops in multipath route
IPv4 allows multipath routes to be deleted using just the prefix and
length. For example:
    $ ip ro ls vrf red
    unreachable default metric 8192
    1.1.1.0/24
        nexthop via 10.100.1.254  dev eth1 weight 1
        nexthop via 10.11.200.2  dev eth11.200 weight 1
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

    $ ip ro del 1.1.1.0/24 vrf red

    $ ip ro ls vrf red
    unreachable default metric 8192
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

The same notation does not work with IPv6 because of how multipath routes
are implemented for IPv6. For IPv6 only the first nexthop of a multipath
route is deleted if the request contains only a prefix and length. This
leads to unnecessary complexity in userspace dealing with IPv6 multipath
routes.

This patch allows all nexthops to be deleted without specifying each one
in the delete request. Internally, this is done by walking the sibling
list of the route matching the specifications given (prefix, length,
metric, protocol, etc).

    $  ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:200::/120 via 2001:db8:1::2 dev eth1 metric 1024  pref medium
    2001:db8:200::/120 via 2001:db8:2::2 dev eth2 metric 1024  pref medium
    ...

    $ ip -6 ro del vrf red 2001:db8:200::/120

    $ ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    ...

Because IPv6 allows individual nexthops to be deleted without deleting
the entire route, the ip6_route_multipath_del and non-multipath code
path (ip6_route_del) have to be discriminated so that all nexthops are
only deleted for the latter case. This is done by making the existing
fc_type in fib6_config a u16 and then adding a new u16 field with
fc_delete_all_nh as the first bit.

Suggested-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-04 19:58:14 -05:00

308 lines
6.8 KiB
C

/*
* 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
#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/spinlock.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/netlink.h>
#include <net/inetpeer.h>
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
#define FIB6_TABLE_HASHSZ 256
#else
#define FIB6_TABLE_HASHSZ 1
#endif
struct rt6_info;
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;
u16 fc_type; /* only 8 bits are used */
u16 fc_delete_all_nh : 1,
__unused : 15;
struct in6_addr fc_dst;
struct in6_addr fc_src;
struct in6_addr fc_prefsrc;
struct in6_addr fc_gateway;
unsigned long fc_expires;
struct nlattr *fc_mx;
int fc_mx_len;
int fc_mp_len;
struct nlattr *fc_mp;
struct nl_info fc_nlinfo;
struct nlattr *fc_encap;
u16 fc_encap_type;
};
struct fib6_node {
struct fib6_node *parent;
struct fib6_node *left;
struct fib6_node *right;
#ifdef CONFIG_IPV6_SUBTREES
struct fib6_node *subtree;
#endif
struct rt6_info *leaf;
__u16 fn_bit; /* bit key */
__u16 fn_flags;
int fn_sernum;
struct rt6_info *rr_ptr;
};
#ifndef CONFIG_IPV6_SUBTREES
#define FIB6_SUBTREE(fn) NULL
#else
#define FIB6_SUBTREE(fn) ((fn)->subtree)
#endif
struct mx6_config {
const u32 *mx;
DECLARE_BITMAP(mx_valid, RTAX_MAX);
};
/*
* routing information
*
*/
struct rt6key {
struct in6_addr addr;
int plen;
};
struct fib6_table;
struct rt6_info {
struct dst_entry dst;
/*
* Tail elements of dst_entry (__refcnt etc.)
* and these elements (rarely used in hot path) are in
* the same cache line.
*/
struct fib6_table *rt6i_table;
struct fib6_node *rt6i_node;
struct in6_addr rt6i_gateway;
/* Multipath routes:
* siblings is a list of rt6_info that have the the same metric/weight,
* destination, but not the same gateway. nsiblings is just a cache
* to speed up lookup.
*/
struct list_head rt6i_siblings;
unsigned int rt6i_nsiblings;
atomic_t rt6i_ref;
/* These are in a separate cache line. */
struct rt6key rt6i_dst ____cacheline_aligned_in_smp;
u32 rt6i_flags;
struct rt6key rt6i_src;
struct rt6key rt6i_prefsrc;
struct list_head rt6i_uncached;
struct uncached_list *rt6i_uncached_list;
struct inet6_dev *rt6i_idev;
struct rt6_info * __percpu *rt6i_pcpu;
u32 rt6i_metric;
u32 rt6i_pmtu;
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
u8 rt6i_protocol;
};
static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
{
return ((struct rt6_info *)dst)->rt6i_idev;
}
static inline void rt6_clean_expires(struct rt6_info *rt)
{
rt->rt6i_flags &= ~RTF_EXPIRES;
rt->dst.expires = 0;
}
static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
{
rt->dst.expires = expires;
rt->rt6i_flags |= RTF_EXPIRES;
}
static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
{
struct rt6_info *rt;
for (rt = rt0; rt && !(rt->rt6i_flags & RTF_EXPIRES);
rt = (struct rt6_info *)rt->dst.from);
if (rt && rt != rt0)
rt0->dst.expires = rt->dst.expires;
dst_set_expires(&rt0->dst, timeout);
rt0->rt6i_flags |= RTF_EXPIRES;
}
static inline u32 rt6_get_cookie(const struct rt6_info *rt)
{
if (rt->rt6i_flags & RTF_PCPU ||
(unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
rt = (struct rt6_info *)(rt->dst.from);
return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
}
static inline void ip6_rt_put(struct rt6_info *rt)
{
/* dst_release() accepts a NULL parameter.
* We rely on dst being first structure in struct rt6_info
*/
BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
dst_release(&rt->dst);
}
enum fib6_walk_state {
#ifdef CONFIG_IPV6_SUBTREES
FWS_S,
#endif
FWS_L,
FWS_R,
FWS_C,
FWS_U
};
struct fib6_walker {
struct list_head lh;
struct fib6_node *root, *node;
struct rt6_info *leaf;
enum fib6_walk_state state;
bool prune;
unsigned int skip;
unsigned int count;
int (*func)(struct fib6_walker *);
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 */
/*
* priority levels (or metrics)
*
*/
struct fib6_table {
struct hlist_node tb6_hlist;
u32 tb6_id;
rwlock_t tb6_lock;
struct fib6_node tb6_root;
struct inet_peer_base tb6_peers;
unsigned int flags;
#define RT6_TABLE_HAS_DFLT_ROUTER BIT(0)
};
#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
#define RT6_TABLE_LOCAL RT_TABLE_LOCAL
#else
#define FIB6_TABLE_MIN RT_TABLE_MAIN
#define FIB6_TABLE_MAX FIB6_TABLE_MIN
#define RT6_TABLE_LOCAL RT6_TABLE_MAIN
#endif
typedef struct rt6_info *(*pol_lookup_t)(struct net *,
struct fib6_table *,
struct flowi6 *, int);
/*
* exported functions
*/
struct fib6_table *fib6_get_table(struct net *net, u32 id);
struct fib6_table *fib6_new_table(struct net *net, u32 id);
struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
int flags, pol_lookup_t lookup);
struct fib6_node *fib6_lookup(struct fib6_node *root,
const struct in6_addr *daddr,
const struct in6_addr *saddr);
struct fib6_node *fib6_locate(struct fib6_node *root,
const struct in6_addr *daddr, int dst_len,
const struct in6_addr *saddr, int src_len);
void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
void *arg);
int fib6_add(struct fib6_node *root, struct rt6_info *rt,
struct nl_info *info, struct mx6_config *mxc);
int fib6_del(struct rt6_info *rt, struct nl_info *info);
void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info,
unsigned int flags);
void fib6_run_gc(unsigned long expires, struct net *net, bool force);
void fib6_gc_cleanup(void);
int fib6_init(void);
int ipv6_route_open(struct inode *inode, struct file *file);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
int fib6_rules_init(void);
void fib6_rules_cleanup(void);
#else
static inline int fib6_rules_init(void)
{
return 0;
}
static inline void fib6_rules_cleanup(void)
{
return ;
}
#endif
#endif