linux/include/net/ip_fib.h
David Ahern 50d889b178 net/ipv4: Add helper to return path MTU based on fib result
Determine path MTU from a FIB lookup result. Logic is a distillation of
ip_dst_mtu_maybe_forward.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22 10:51:09 +02:00

455 lines
11 KiB
C

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for the Forwarding Information Base.
*
* Authors: A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* 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 _NET_IP_FIB_H
#define _NET_IP_FIB_H
#include <net/flow.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <net/fib_notifier.h>
#include <net/fib_rules.h>
#include <net/inetpeer.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/refcount.h>
struct fib_config {
u8 fc_dst_len;
u8 fc_tos;
u8 fc_protocol;
u8 fc_scope;
u8 fc_type;
/* 3 bytes unused */
u32 fc_table;
__be32 fc_dst;
__be32 fc_gw;
int fc_oif;
u32 fc_flags;
u32 fc_priority;
__be32 fc_prefsrc;
struct nlattr *fc_mx;
struct rtnexthop *fc_mp;
int fc_mx_len;
int fc_mp_len;
u32 fc_flow;
u32 fc_nlflags;
struct nl_info fc_nlinfo;
struct nlattr *fc_encap;
u16 fc_encap_type;
};
struct fib_info;
struct rtable;
struct fib_nh_exception {
struct fib_nh_exception __rcu *fnhe_next;
int fnhe_genid;
__be32 fnhe_daddr;
u32 fnhe_pmtu;
bool fnhe_mtu_locked;
__be32 fnhe_gw;
unsigned long fnhe_expires;
struct rtable __rcu *fnhe_rth_input;
struct rtable __rcu *fnhe_rth_output;
unsigned long fnhe_stamp;
struct rcu_head rcu;
};
struct fnhe_hash_bucket {
struct fib_nh_exception __rcu *chain;
};
#define FNHE_HASH_SHIFT 11
#define FNHE_HASH_SIZE (1 << FNHE_HASH_SHIFT)
#define FNHE_RECLAIM_DEPTH 5
struct fib_nh {
struct net_device *nh_dev;
struct hlist_node nh_hash;
struct fib_info *nh_parent;
unsigned int nh_flags;
unsigned char nh_scope;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int nh_weight;
atomic_t nh_upper_bound;
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
__u32 nh_tclassid;
#endif
int nh_oif;
__be32 nh_gw;
__be32 nh_saddr;
int nh_saddr_genid;
struct rtable __rcu * __percpu *nh_pcpu_rth_output;
struct rtable __rcu *nh_rth_input;
struct fnhe_hash_bucket __rcu *nh_exceptions;
struct lwtunnel_state *nh_lwtstate;
};
/*
* This structure contains data shared by many of routes.
*/
struct fib_info {
struct hlist_node fib_hash;
struct hlist_node fib_lhash;
struct net *fib_net;
int fib_treeref;
refcount_t fib_clntref;
unsigned int fib_flags;
unsigned char fib_dead;
unsigned char fib_protocol;
unsigned char fib_scope;
unsigned char fib_type;
__be32 fib_prefsrc;
u32 fib_tb_id;
u32 fib_priority;
struct dst_metrics *fib_metrics;
#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
int fib_nhs;
struct rcu_head rcu;
struct fib_nh fib_nh[0];
#define fib_dev fib_nh[0].nh_dev
};
#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_rule;
#endif
struct fib_table;
struct fib_result {
__be32 prefix;
unsigned char prefixlen;
unsigned char nh_sel;
unsigned char type;
unsigned char scope;
u32 tclassid;
struct fib_info *fi;
struct fib_table *table;
struct hlist_head *fa_head;
};
struct fib_result_nl {
__be32 fl_addr; /* To be looked up*/
u32 fl_mark;
unsigned char fl_tos;
unsigned char fl_scope;
unsigned char tb_id_in;
unsigned char tb_id; /* Results */
unsigned char prefixlen;
unsigned char nh_sel;
unsigned char type;
unsigned char scope;
int err;
};
#ifdef CONFIG_IP_ROUTE_MULTIPATH
#define FIB_RES_NH(res) ((res).fi->fib_nh[(res).nh_sel])
#else /* CONFIG_IP_ROUTE_MULTIPATH */
#define FIB_RES_NH(res) ((res).fi->fib_nh[0])
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
#ifdef CONFIG_IP_MULTIPLE_TABLES
#define FIB_TABLE_HASHSZ 256
#else
#define FIB_TABLE_HASHSZ 2
#endif
__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);
#define FIB_RES_SADDR(net, res) \
((FIB_RES_NH(res).nh_saddr_genid == \
atomic_read(&(net)->ipv4.dev_addr_genid)) ? \
FIB_RES_NH(res).nh_saddr : \
fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))
#define FIB_RES_GW(res) (FIB_RES_NH(res).nh_gw)
#define FIB_RES_DEV(res) (FIB_RES_NH(res).nh_dev)
#define FIB_RES_OIF(res) (FIB_RES_NH(res).nh_oif)
#define FIB_RES_PREFSRC(net, res) ((res).fi->fib_prefsrc ? : \
FIB_RES_SADDR(net, res))
struct fib_entry_notifier_info {
struct fib_notifier_info info; /* must be first */
u32 dst;
int dst_len;
struct fib_info *fi;
u8 tos;
u8 type;
u32 tb_id;
};
struct fib_nh_notifier_info {
struct fib_notifier_info info; /* must be first */
struct fib_nh *fib_nh;
};
int call_fib4_notifier(struct notifier_block *nb, struct net *net,
enum fib_event_type event_type,
struct fib_notifier_info *info);
int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info);
int __net_init fib4_notifier_init(struct net *net);
void __net_exit fib4_notifier_exit(struct net *net);
void fib_notify(struct net *net, struct notifier_block *nb);
struct fib_table {
struct hlist_node tb_hlist;
u32 tb_id;
int tb_num_default;
struct rcu_head rcu;
unsigned long *tb_data;
unsigned long __data[0];
};
int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
struct fib_result *res, int fib_flags);
int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
struct netlink_ext_ack *extack);
int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
struct netlink_ext_ack *extack);
int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
struct netlink_callback *cb);
int fib_table_flush(struct net *net, struct fib_table *table);
struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
void fib_table_flush_external(struct fib_table *table);
void fib_free_table(struct fib_table *tb);
#ifndef CONFIG_IP_MULTIPLE_TABLES
#define TABLE_LOCAL_INDEX (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
#define TABLE_MAIN_INDEX (RT_TABLE_MAIN & (FIB_TABLE_HASHSZ - 1))
static inline struct fib_table *fib_get_table(struct net *net, u32 id)
{
struct hlist_node *tb_hlist;
struct hlist_head *ptr;
ptr = id == RT_TABLE_LOCAL ?
&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));
return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
}
static inline struct fib_table *fib_new_table(struct net *net, u32 id)
{
return fib_get_table(net, id);
}
static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
struct fib_result *res, unsigned int flags)
{
struct fib_table *tb;
int err = -ENETUNREACH;
rcu_read_lock();
tb = fib_get_table(net, RT_TABLE_MAIN);
if (tb)
err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);
if (err == -EAGAIN)
err = -ENETUNREACH;
rcu_read_unlock();
return err;
}
static inline bool fib4_rule_default(const struct fib_rule *rule)
{
return true;
}
static inline int fib4_rules_dump(struct net *net, struct notifier_block *nb)
{
return 0;
}
static inline unsigned int fib4_rules_seq_read(struct net *net)
{
return 0;
}
static inline bool fib4_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi4 *fl4,
struct flow_keys *flkeys)
{
return false;
}
#else /* CONFIG_IP_MULTIPLE_TABLES */
int __net_init fib4_rules_init(struct net *net);
void __net_exit fib4_rules_exit(struct net *net);
struct fib_table *fib_new_table(struct net *net, u32 id);
struct fib_table *fib_get_table(struct net *net, u32 id);
int __fib_lookup(struct net *net, struct flowi4 *flp,
struct fib_result *res, unsigned int flags);
static inline int fib_lookup(struct net *net, struct flowi4 *flp,
struct fib_result *res, unsigned int flags)
{
struct fib_table *tb;
int err = -ENETUNREACH;
flags |= FIB_LOOKUP_NOREF;
if (net->ipv4.fib_has_custom_rules)
return __fib_lookup(net, flp, res, flags);
rcu_read_lock();
res->tclassid = 0;
tb = rcu_dereference_rtnl(net->ipv4.fib_main);
if (tb)
err = fib_table_lookup(tb, flp, res, flags);
if (!err)
goto out;
tb = rcu_dereference_rtnl(net->ipv4.fib_default);
if (tb)
err = fib_table_lookup(tb, flp, res, flags);
out:
if (err == -EAGAIN)
err = -ENETUNREACH;
rcu_read_unlock();
return err;
}
bool fib4_rule_default(const struct fib_rule *rule);
int fib4_rules_dump(struct net *net, struct notifier_block *nb);
unsigned int fib4_rules_seq_read(struct net *net);
static inline bool fib4_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi4 *fl4,
struct flow_keys *flkeys)
{
unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
if (!net->ipv4.fib_rules_require_fldissect)
return false;
skb_flow_dissect_flow_keys(skb, flkeys, flag);
fl4->fl4_sport = flkeys->ports.src;
fl4->fl4_dport = flkeys->ports.dst;
fl4->flowi4_proto = flkeys->basic.ip_proto;
return true;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */
/* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[];
void ip_fib_init(void);
__be32 fib_compute_spec_dst(struct sk_buff *skb);
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
u8 tos, int oif, struct net_device *dev,
struct in_device *idev, u32 *itag);
#ifdef CONFIG_IP_ROUTE_CLASSID
static inline int fib_num_tclassid_users(struct net *net)
{
return net->ipv4.fib_num_tclassid_users;
}
#else
static inline int fib_num_tclassid_users(struct net *net)
{
return 0;
}
#endif
int fib_unmerge(struct net *net);
/* Exported by fib_semantics.c */
int ip_fib_check_default(__be32 gw, struct net_device *dev);
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
int fib_sync_down_addr(struct net_device *dev, __be32 local);
int fib_sync_up(struct net_device *dev, unsigned int nh_flags);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
const struct sk_buff *skb, struct flow_keys *flkeys);
#endif
void fib_select_multipath(struct fib_result *res, int hash);
void fib_select_path(struct net *net, struct fib_result *res,
struct flowi4 *fl4, const struct sk_buff *skb);
/* Exported by fib_trie.c */
void fib_trie_init(void);
struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
#ifdef CONFIG_IP_MULTIPLE_TABLES
u32 rtag;
#endif
*itag = FIB_RES_NH(*res).nh_tclassid<<16;
#ifdef CONFIG_IP_MULTIPLE_TABLES
rtag = res->tclassid;
if (*itag == 0)
*itag = (rtag<<16);
*itag |= (rtag>>16);
#endif
#endif
}
void free_fib_info(struct fib_info *fi);
static inline void fib_info_hold(struct fib_info *fi)
{
refcount_inc(&fi->fib_clntref);
}
static inline void fib_info_put(struct fib_info *fi)
{
if (refcount_dec_and_test(&fi->fib_clntref))
free_fib_info(fi);
}
#ifdef CONFIG_PROC_FS
int __net_init fib_proc_init(struct net *net);
void __net_exit fib_proc_exit(struct net *net);
#else
static inline int fib_proc_init(struct net *net)
{
return 0;
}
static inline void fib_proc_exit(struct net *net)
{
}
#endif
u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);
#endif /* _NET_FIB_H */