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/* SPDX-License-Identifier: GPL-2.0-or-later */
* Linux INET6 implementation
* Authors:
* Pedro Roque <>
#ifndef _IP6_FIB_H
#define _IP6_FIB_H
#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/ip_fib.h>
#include <net/netlink.h>
#include <net/inetpeer.h>
#include <net/fib_notifier.h>
#define FIB6_TABLE_HASHSZ 256
#define RT6_DEBUG 2
#if RT6_DEBUG >= 3
#define RT6_TRACE(x...) pr_debug(x)
#define RT6_TRACE(x...) do { ; } while (0)
struct rt6_info;
struct fib6_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 : 14;
u32 fc_nh_id;
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 __rcu *parent;
struct fib6_node __rcu *left;
struct fib6_node __rcu *right;
struct fib6_node __rcu *subtree;
struct fib6_info __rcu *leaf;
__u16 fn_bit; /* bit key */
__u16 fn_flags;
int fn_sernum;
struct fib6_info __rcu *rr_ptr;
struct rcu_head rcu;
struct fib6_gc_args {
int timeout;
int more;
#define FIB6_SUBTREE(fn) NULL
#define FIB6_SUBTREE(fn) (rcu_dereference_protected((fn)->subtree, 1))
* routing information
struct rt6key {
struct in6_addr addr;
int plen;
struct fib6_table;
struct rt6_exception_bucket {
struct hlist_head chain;
int depth;
struct rt6_exception {
struct hlist_node hlist;
struct rt6_info *rt6i;
unsigned long stamp;
struct rcu_head rcu;
#define FIB6_MAX_DEPTH 5
struct fib6_nh {
struct fib_nh_common nh_common;
unsigned long last_probe;
struct rt6_info * __percpu *rt6i_pcpu;
struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
struct fib6_info {
struct fib6_table *fib6_table;
struct fib6_info __rcu *fib6_next;
struct fib6_node __rcu *fib6_node;
/* Multipath routes:
* siblings is a list of fib6_info that have the the same metric/weight,
* destination, but not the same gateway. nsiblings is just a cache
* to speed up lookup.
union {
struct list_head fib6_siblings;
struct list_head nh_list;
unsigned int fib6_nsiblings;
refcount_t fib6_ref;
unsigned long expires;
struct dst_metrics *fib6_metrics;
#define fib6_pmtu fib6_metrics->metrics[RTAX_MTU-1]
struct rt6key fib6_dst;
u32 fib6_flags;
struct rt6key fib6_src;
struct rt6key fib6_prefsrc;
u32 fib6_metric;
u8 fib6_protocol;
u8 fib6_type;
u8 should_flush:1,
struct rcu_head rcu;
struct nexthop *nh;
struct fib6_nh fib6_nh[0];
struct rt6_info {
struct dst_entry dst;
struct fib6_info __rcu *from;
int sernum;
struct rt6key rt6i_dst;
struct rt6key rt6i_src;
struct in6_addr rt6i_gateway;
struct inet6_dev *rt6i_idev;
u32 rt6i_flags;
struct list_head rt6i_uncached;
struct uncached_list *rt6i_uncached_list;
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
struct fib6_result {
struct fib6_nh *nh;
struct fib6_info *f6i;
u32 fib6_flags;
u8 fib6_type;
struct rt6_info *rt6;
#define for_each_fib6_node_rt_rcu(fn) \
for (rt = rcu_dereference((fn)->leaf); rt; \
rt = rcu_dereference(rt->fib6_next))
#define for_each_fib6_walker_rt(w) \
for (rt = (w)->leaf; rt; \
rt = rcu_dereference_protected(rt->fib6_next, 1))
static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
return ((struct rt6_info *)dst)->rt6i_idev;
static inline void fib6_clean_expires(struct fib6_info *f6i)
f6i->fib6_flags &= ~RTF_EXPIRES;
f6i->expires = 0;
static inline void fib6_set_expires(struct fib6_info *f6i,
unsigned long expires)
f6i->expires = expires;
f6i->fib6_flags |= RTF_EXPIRES;
static inline bool fib6_check_expired(const struct fib6_info *f6i)
if (f6i->fib6_flags & RTF_EXPIRES)
return time_after(jiffies, f6i->expires);
return false;
/* Function to safely get fn->sernum for passed in rt
* and store result in passed in cookie.
* Return true if we can get cookie safely
* Return false if not
static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
u32 *cookie)
struct fib6_node *fn;
bool status = false;
fn = rcu_dereference(f6i->fib6_node);
if (fn) {
*cookie = fn->fn_sernum;
/* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
status = true;
return status;
static inline u32 rt6_get_cookie(const struct rt6_info *rt)
struct fib6_info *from;
u32 cookie = 0;
if (rt->sernum)
return rt->sernum;
from = rcu_dereference(rt->from);
if (from)
fib6_get_cookie_safe(from, &cookie);
return cookie;
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);
struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
void fib6_info_destroy_rcu(struct rcu_head *head);
static inline void fib6_info_hold(struct fib6_info *f6i)
static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
return refcount_inc_not_zero(&f6i->fib6_ref);
static inline void fib6_info_release(struct fib6_info *f6i)
if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
enum fib6_walk_state {
struct fib6_walker {
struct list_head lh;
struct fib6_node *root, *node;
struct fib6_info *leaf;
enum fib6_walk_state state;
unsigned int skip;
unsigned int count;
unsigned int skip_in_node;
int (*func)(struct fib6_walker *);
void *args;
struct rt6_statistics {
__u32 fib_nodes; /* all fib6 nodes */
__u32 fib_route_nodes; /* intermediate nodes */
__u32 fib_rt_entries; /* rt entries in fib table */
__u32 fib_rt_cache; /* cached rt entries in exception table */
__u32 fib_discarded_routes; /* total number of routes delete */
/* The following stats are not protected by any lock */
atomic_t fib_rt_alloc; /* total number of routes alloced */
atomic_t fib_rt_uncache; /* rt entries in uncached list */
#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;
spinlock_t tb6_lock;
struct fib6_node tb6_root;
struct inet_peer_base tb6_peers;
unsigned int flags;
unsigned int fib_seq;
#define FIB6_TABLE_MIN 1
typedef struct rt6_info *(*pol_lookup_t)(struct net *,
struct fib6_table *,
struct flowi6 *,
const struct sk_buff *, int);
struct fib6_entry_notifier_info {
struct fib_notifier_info info; /* must be first */
struct fib6_info *rt;
unsigned int nsiblings;
* 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,
const struct sk_buff *skb,
int flags, pol_lookup_t lookup);
/* called with rcu lock held; can return error pointer
* caller needs to select path
int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
struct fib6_result *res, int flags);
/* called with rcu lock held; caller needs to select path */
int fib6_table_lookup(struct net *net, struct fib6_table *table,
int oif, struct flowi6 *fl6, struct fib6_result *res,
int strict);
void fib6_select_path(const struct net *net, struct fib6_result *res,
struct flowi6 *fl6, int oif, bool have_oif_match,
const struct sk_buff *skb, int strict);
struct fib6_node *fib6_node_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,
bool exact_match);
void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
void *arg);
void fib6_clean_all_skip_notify(struct net *net,
int (*func)(struct fib6_info *, void *arg),
void *arg);
int fib6_add(struct fib6_node *root, struct fib6_info *rt,
struct nl_info *info, struct netlink_ext_ack *extack);
int fib6_del(struct fib6_info *rt, struct nl_info *info);
static inline
void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
const struct fib6_info *from;
from = rcu_dereference(rt->from);
if (from) {
*addr = from->fib6_prefsrc.addr;
} else {
struct in6_addr in6_zero = {};
*addr = in6_zero;
int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
struct fib6_config *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack);
void fib6_nh_release(struct fib6_nh *fib6_nh);
void fib6_nh_release_dsts(struct fib6_nh *fib6_nh);
int call_fib6_entry_notifiers(struct net *net,
enum fib_event_type event_type,
struct fib6_info *rt,
struct netlink_ext_ack *extack);
int call_fib6_multipath_entry_notifiers(struct net *net,
enum fib_event_type event_type,
struct fib6_info *rt,
unsigned int nsiblings,
struct netlink_ext_ack *extack);
void fib6_rt_update(struct net *net, struct fib6_info *rt,
struct nl_info *info);
void inet6_rt_notify(int event, struct fib6_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);
struct ipv6_route_iter {
struct seq_net_private p;
struct fib6_walker w;
loff_t skip;
struct fib6_table *tbl;
int sernum;
extern const struct seq_operations ipv6_route_seq_ops;
int call_fib6_notifier(struct notifier_block *nb, struct net *net,
enum fib_event_type event_type,
struct fib_notifier_info *info);
int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info);
int __net_init fib6_notifier_init(struct net *net);
void __net_exit fib6_notifier_exit(struct net *net);
unsigned int fib6_tables_seq_read(struct net *net);
int fib6_tables_dump(struct net *net, struct notifier_block *nb);
void fib6_update_sernum(struct net *net, struct fib6_info *rt);
void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
int fib6_rules_init(void);
void fib6_rules_cleanup(void);
bool fib6_rule_default(const struct fib_rule *rule);
int fib6_rules_dump(struct net *net, struct notifier_block *nb);
unsigned int fib6_rules_seq_read(struct net *net);
static inline bool fib6_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi6 *fl6,
struct flow_keys *flkeys)
unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
if (!net->ipv6.fib6_rules_require_fldissect)
return false;
skb_flow_dissect_flow_keys(skb, flkeys, flag);
fl6->fl6_sport = flkeys->ports.src;
fl6->fl6_dport = flkeys->ports.dst;
fl6->flowi6_proto = flkeys->basic.ip_proto;
return true;
static inline int fib6_rules_init(void)
return 0;
static inline void fib6_rules_cleanup(void)
return ;
static inline bool fib6_rule_default(const struct fib_rule *rule)
return true;
static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
return 0;
static inline unsigned int fib6_rules_seq_read(struct net *net)
return 0;
static inline bool fib6_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi6 *fl6,
struct flow_keys *flkeys)
return false;