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50d889b178
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>
455 lines
11 KiB
C
455 lines
11 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Definitions for the Forwarding Information Base.
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*
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* Authors: A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _NET_IP_FIB_H
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#define _NET_IP_FIB_H
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#include <net/flow.h>
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#include <linux/seq_file.h>
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#include <linux/rcupdate.h>
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#include <net/fib_notifier.h>
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#include <net/fib_rules.h>
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#include <net/inetpeer.h>
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#include <linux/percpu.h>
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#include <linux/notifier.h>
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#include <linux/refcount.h>
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struct fib_config {
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u8 fc_dst_len;
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u8 fc_tos;
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u8 fc_protocol;
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u8 fc_scope;
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u8 fc_type;
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/* 3 bytes unused */
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u32 fc_table;
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__be32 fc_dst;
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__be32 fc_gw;
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int fc_oif;
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u32 fc_flags;
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u32 fc_priority;
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__be32 fc_prefsrc;
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struct nlattr *fc_mx;
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struct rtnexthop *fc_mp;
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int fc_mx_len;
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int fc_mp_len;
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u32 fc_flow;
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u32 fc_nlflags;
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struct nl_info fc_nlinfo;
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struct nlattr *fc_encap;
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u16 fc_encap_type;
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};
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struct fib_info;
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struct rtable;
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struct fib_nh_exception {
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struct fib_nh_exception __rcu *fnhe_next;
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int fnhe_genid;
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__be32 fnhe_daddr;
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u32 fnhe_pmtu;
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bool fnhe_mtu_locked;
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__be32 fnhe_gw;
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unsigned long fnhe_expires;
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struct rtable __rcu *fnhe_rth_input;
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struct rtable __rcu *fnhe_rth_output;
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unsigned long fnhe_stamp;
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struct rcu_head rcu;
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};
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struct fnhe_hash_bucket {
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struct fib_nh_exception __rcu *chain;
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};
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#define FNHE_HASH_SHIFT 11
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#define FNHE_HASH_SIZE (1 << FNHE_HASH_SHIFT)
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#define FNHE_RECLAIM_DEPTH 5
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struct fib_nh {
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struct net_device *nh_dev;
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struct hlist_node nh_hash;
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struct fib_info *nh_parent;
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unsigned int nh_flags;
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unsigned char nh_scope;
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#ifdef CONFIG_IP_ROUTE_MULTIPATH
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int nh_weight;
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atomic_t nh_upper_bound;
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#endif
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#ifdef CONFIG_IP_ROUTE_CLASSID
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__u32 nh_tclassid;
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#endif
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int nh_oif;
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__be32 nh_gw;
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__be32 nh_saddr;
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int nh_saddr_genid;
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struct rtable __rcu * __percpu *nh_pcpu_rth_output;
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struct rtable __rcu *nh_rth_input;
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struct fnhe_hash_bucket __rcu *nh_exceptions;
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struct lwtunnel_state *nh_lwtstate;
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};
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/*
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* This structure contains data shared by many of routes.
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*/
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struct fib_info {
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struct hlist_node fib_hash;
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struct hlist_node fib_lhash;
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struct net *fib_net;
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int fib_treeref;
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refcount_t fib_clntref;
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unsigned int fib_flags;
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unsigned char fib_dead;
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unsigned char fib_protocol;
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unsigned char fib_scope;
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unsigned char fib_type;
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__be32 fib_prefsrc;
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u32 fib_tb_id;
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u32 fib_priority;
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struct dst_metrics *fib_metrics;
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#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
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#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
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#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
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#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
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int fib_nhs;
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struct rcu_head rcu;
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struct fib_nh fib_nh[0];
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#define fib_dev fib_nh[0].nh_dev
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};
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#ifdef CONFIG_IP_MULTIPLE_TABLES
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struct fib_rule;
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#endif
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struct fib_table;
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struct fib_result {
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__be32 prefix;
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unsigned char prefixlen;
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unsigned char nh_sel;
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unsigned char type;
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unsigned char scope;
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u32 tclassid;
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struct fib_info *fi;
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struct fib_table *table;
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struct hlist_head *fa_head;
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};
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struct fib_result_nl {
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__be32 fl_addr; /* To be looked up*/
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u32 fl_mark;
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unsigned char fl_tos;
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unsigned char fl_scope;
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unsigned char tb_id_in;
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unsigned char tb_id; /* Results */
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unsigned char prefixlen;
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unsigned char nh_sel;
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unsigned char type;
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unsigned char scope;
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int err;
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};
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#ifdef CONFIG_IP_ROUTE_MULTIPATH
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#define FIB_RES_NH(res) ((res).fi->fib_nh[(res).nh_sel])
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#else /* CONFIG_IP_ROUTE_MULTIPATH */
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#define FIB_RES_NH(res) ((res).fi->fib_nh[0])
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#endif /* CONFIG_IP_ROUTE_MULTIPATH */
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#ifdef CONFIG_IP_MULTIPLE_TABLES
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#define FIB_TABLE_HASHSZ 256
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#else
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#define FIB_TABLE_HASHSZ 2
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#endif
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__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);
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#define FIB_RES_SADDR(net, res) \
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((FIB_RES_NH(res).nh_saddr_genid == \
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atomic_read(&(net)->ipv4.dev_addr_genid)) ? \
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FIB_RES_NH(res).nh_saddr : \
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fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))
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#define FIB_RES_GW(res) (FIB_RES_NH(res).nh_gw)
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#define FIB_RES_DEV(res) (FIB_RES_NH(res).nh_dev)
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#define FIB_RES_OIF(res) (FIB_RES_NH(res).nh_oif)
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#define FIB_RES_PREFSRC(net, res) ((res).fi->fib_prefsrc ? : \
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FIB_RES_SADDR(net, res))
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struct fib_entry_notifier_info {
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struct fib_notifier_info info; /* must be first */
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u32 dst;
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int dst_len;
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struct fib_info *fi;
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u8 tos;
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u8 type;
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u32 tb_id;
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};
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struct fib_nh_notifier_info {
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struct fib_notifier_info info; /* must be first */
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struct fib_nh *fib_nh;
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};
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int call_fib4_notifier(struct notifier_block *nb, struct net *net,
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enum fib_event_type event_type,
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struct fib_notifier_info *info);
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int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
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struct fib_notifier_info *info);
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int __net_init fib4_notifier_init(struct net *net);
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void __net_exit fib4_notifier_exit(struct net *net);
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void fib_notify(struct net *net, struct notifier_block *nb);
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struct fib_table {
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struct hlist_node tb_hlist;
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u32 tb_id;
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int tb_num_default;
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struct rcu_head rcu;
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unsigned long *tb_data;
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unsigned long __data[0];
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};
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int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
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struct fib_result *res, int fib_flags);
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int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
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struct netlink_ext_ack *extack);
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int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
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struct netlink_ext_ack *extack);
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int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
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struct netlink_callback *cb);
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int fib_table_flush(struct net *net, struct fib_table *table);
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struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
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void fib_table_flush_external(struct fib_table *table);
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void fib_free_table(struct fib_table *tb);
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#ifndef CONFIG_IP_MULTIPLE_TABLES
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#define TABLE_LOCAL_INDEX (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
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#define TABLE_MAIN_INDEX (RT_TABLE_MAIN & (FIB_TABLE_HASHSZ - 1))
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static inline struct fib_table *fib_get_table(struct net *net, u32 id)
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{
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struct hlist_node *tb_hlist;
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struct hlist_head *ptr;
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ptr = id == RT_TABLE_LOCAL ?
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&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
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&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
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tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));
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return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
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}
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static inline struct fib_table *fib_new_table(struct net *net, u32 id)
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{
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return fib_get_table(net, id);
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}
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static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
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struct fib_result *res, unsigned int flags)
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{
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struct fib_table *tb;
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int err = -ENETUNREACH;
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rcu_read_lock();
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tb = fib_get_table(net, RT_TABLE_MAIN);
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if (tb)
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err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);
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if (err == -EAGAIN)
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err = -ENETUNREACH;
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rcu_read_unlock();
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return err;
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}
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static inline bool fib4_rule_default(const struct fib_rule *rule)
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{
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return true;
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}
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static inline int fib4_rules_dump(struct net *net, struct notifier_block *nb)
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{
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return 0;
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}
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static inline unsigned int fib4_rules_seq_read(struct net *net)
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{
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return 0;
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}
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static inline bool fib4_rules_early_flow_dissect(struct net *net,
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struct sk_buff *skb,
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struct flowi4 *fl4,
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struct flow_keys *flkeys)
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{
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return false;
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}
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#else /* CONFIG_IP_MULTIPLE_TABLES */
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int __net_init fib4_rules_init(struct net *net);
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void __net_exit fib4_rules_exit(struct net *net);
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struct fib_table *fib_new_table(struct net *net, u32 id);
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struct fib_table *fib_get_table(struct net *net, u32 id);
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int __fib_lookup(struct net *net, struct flowi4 *flp,
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struct fib_result *res, unsigned int flags);
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static inline int fib_lookup(struct net *net, struct flowi4 *flp,
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struct fib_result *res, unsigned int flags)
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{
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struct fib_table *tb;
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int err = -ENETUNREACH;
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flags |= FIB_LOOKUP_NOREF;
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if (net->ipv4.fib_has_custom_rules)
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return __fib_lookup(net, flp, res, flags);
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rcu_read_lock();
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res->tclassid = 0;
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tb = rcu_dereference_rtnl(net->ipv4.fib_main);
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if (tb)
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err = fib_table_lookup(tb, flp, res, flags);
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if (!err)
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goto out;
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tb = rcu_dereference_rtnl(net->ipv4.fib_default);
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if (tb)
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err = fib_table_lookup(tb, flp, res, flags);
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out:
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if (err == -EAGAIN)
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err = -ENETUNREACH;
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rcu_read_unlock();
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return err;
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}
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bool fib4_rule_default(const struct fib_rule *rule);
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int fib4_rules_dump(struct net *net, struct notifier_block *nb);
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unsigned int fib4_rules_seq_read(struct net *net);
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static inline bool fib4_rules_early_flow_dissect(struct net *net,
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struct sk_buff *skb,
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struct flowi4 *fl4,
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struct flow_keys *flkeys)
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{
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unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
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if (!net->ipv4.fib_rules_require_fldissect)
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return false;
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skb_flow_dissect_flow_keys(skb, flkeys, flag);
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fl4->fl4_sport = flkeys->ports.src;
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fl4->fl4_dport = flkeys->ports.dst;
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fl4->flowi4_proto = flkeys->basic.ip_proto;
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return true;
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}
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#endif /* CONFIG_IP_MULTIPLE_TABLES */
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/* Exported by fib_frontend.c */
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extern const struct nla_policy rtm_ipv4_policy[];
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void ip_fib_init(void);
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__be32 fib_compute_spec_dst(struct sk_buff *skb);
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int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
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u8 tos, int oif, struct net_device *dev,
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struct in_device *idev, u32 *itag);
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#ifdef CONFIG_IP_ROUTE_CLASSID
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static inline int fib_num_tclassid_users(struct net *net)
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{
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return net->ipv4.fib_num_tclassid_users;
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}
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#else
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static inline int fib_num_tclassid_users(struct net *net)
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{
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return 0;
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}
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#endif
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int fib_unmerge(struct net *net);
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/* Exported by fib_semantics.c */
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int ip_fib_check_default(__be32 gw, struct net_device *dev);
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int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
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int fib_sync_down_addr(struct net_device *dev, __be32 local);
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int fib_sync_up(struct net_device *dev, unsigned int nh_flags);
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#ifdef CONFIG_IP_ROUTE_MULTIPATH
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int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
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const struct sk_buff *skb, struct flow_keys *flkeys);
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#endif
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void fib_select_multipath(struct fib_result *res, int hash);
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void fib_select_path(struct net *net, struct fib_result *res,
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struct flowi4 *fl4, const struct sk_buff *skb);
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/* Exported by fib_trie.c */
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void fib_trie_init(void);
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struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
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static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
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{
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#ifdef CONFIG_IP_ROUTE_CLASSID
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#ifdef CONFIG_IP_MULTIPLE_TABLES
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u32 rtag;
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#endif
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*itag = FIB_RES_NH(*res).nh_tclassid<<16;
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#ifdef CONFIG_IP_MULTIPLE_TABLES
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rtag = res->tclassid;
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if (*itag == 0)
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*itag = (rtag<<16);
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*itag |= (rtag>>16);
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#endif
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#endif
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}
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void free_fib_info(struct fib_info *fi);
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static inline void fib_info_hold(struct fib_info *fi)
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{
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refcount_inc(&fi->fib_clntref);
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}
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static inline void fib_info_put(struct fib_info *fi)
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{
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if (refcount_dec_and_test(&fi->fib_clntref))
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free_fib_info(fi);
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}
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#ifdef CONFIG_PROC_FS
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int __net_init fib_proc_init(struct net *net);
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void __net_exit fib_proc_exit(struct net *net);
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#else
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static inline int fib_proc_init(struct net *net)
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{
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return 0;
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}
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static inline void fib_proc_exit(struct net *net)
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{
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}
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#endif
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u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);
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#endif /* _NET_FIB_H */
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