![Eric Dumazet](/assets/img/avatar_default.png)
net_hash_mix() currently uses kernel address of a struct net,
and is used in many places that could be used to reveal this
address to a patient attacker, thus defeating KASLR, for
the typical case (initial net namespace, &init_net is
not dynamically allocated)
I believe the original implementation tried to avoid spending
too many cycles in this function, but security comes first.
Also provide entropy regardless of CONFIG_NET_NS.
Fixes: 0b4419162a
("netns: introduce the net_hash_mix "salt" for hashes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Amit Klein <aksecurity@gmail.com>
Reported-by: Benny Pinkas <benny@pinkas.net>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
451 lines
11 KiB
C
451 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Operations on the network namespace
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*/
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#ifndef __NET_NET_NAMESPACE_H
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#define __NET_NET_NAMESPACE_H
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#include <linux/atomic.h>
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#include <linux/refcount.h>
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#include <linux/workqueue.h>
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#include <linux/list.h>
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#include <linux/sysctl.h>
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#include <linux/uidgid.h>
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#include <net/flow.h>
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#include <net/netns/core.h>
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#include <net/netns/mib.h>
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#include <net/netns/unix.h>
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#include <net/netns/packet.h>
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#include <net/netns/ipv4.h>
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#include <net/netns/ipv6.h>
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#include <net/netns/ieee802154_6lowpan.h>
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#include <net/netns/sctp.h>
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#include <net/netns/dccp.h>
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#include <net/netns/netfilter.h>
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#include <net/netns/x_tables.h>
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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#include <net/netns/conntrack.h>
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#endif
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#include <net/netns/nftables.h>
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#include <net/netns/xfrm.h>
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#include <net/netns/mpls.h>
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#include <net/netns/can.h>
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#include <net/netns/xdp.h>
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#include <linux/ns_common.h>
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#include <linux/idr.h>
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#include <linux/skbuff.h>
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struct user_namespace;
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struct proc_dir_entry;
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struct net_device;
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struct sock;
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struct ctl_table_header;
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struct net_generic;
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struct uevent_sock;
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struct netns_ipvs;
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struct bpf_prog;
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#define NETDEV_HASHBITS 8
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#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
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struct net {
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refcount_t passive; /* To decided when the network
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* namespace should be freed.
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*/
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refcount_t count; /* To decided when the network
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* namespace should be shut down.
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*/
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spinlock_t rules_mod_lock;
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u32 hash_mix;
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atomic64_t cookie_gen;
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struct list_head list; /* list of network namespaces */
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struct list_head exit_list; /* To linked to call pernet exit
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* methods on dead net (
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* pernet_ops_rwsem read locked),
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* or to unregister pernet ops
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* (pernet_ops_rwsem write locked).
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*/
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struct llist_node cleanup_list; /* namespaces on death row */
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struct user_namespace *user_ns; /* Owning user namespace */
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struct ucounts *ucounts;
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spinlock_t nsid_lock;
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struct idr netns_ids;
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struct ns_common ns;
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struct proc_dir_entry *proc_net;
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struct proc_dir_entry *proc_net_stat;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_set sysctls;
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#endif
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struct sock *rtnl; /* rtnetlink socket */
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struct sock *genl_sock;
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struct uevent_sock *uevent_sock; /* uevent socket */
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struct list_head dev_base_head;
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struct hlist_head *dev_name_head;
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struct hlist_head *dev_index_head;
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unsigned int dev_base_seq; /* protected by rtnl_mutex */
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int ifindex;
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unsigned int dev_unreg_count;
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/* core fib_rules */
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struct list_head rules_ops;
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struct list_head fib_notifier_ops; /* Populated by
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* register_pernet_subsys()
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*/
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struct net_device *loopback_dev; /* The loopback */
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struct netns_core core;
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struct netns_mib mib;
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struct netns_packet packet;
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struct netns_unix unx;
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struct netns_ipv4 ipv4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct netns_ipv6 ipv6;
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#endif
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#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
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struct netns_ieee802154_lowpan ieee802154_lowpan;
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#endif
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#if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
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struct netns_sctp sctp;
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#endif
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#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
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struct netns_dccp dccp;
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#endif
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#ifdef CONFIG_NETFILTER
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struct netns_nf nf;
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struct netns_xt xt;
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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struct netns_ct ct;
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#endif
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#if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
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struct netns_nftables nft;
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#endif
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#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
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struct netns_nf_frag nf_frag;
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struct ctl_table_header *nf_frag_frags_hdr;
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#endif
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struct sock *nfnl;
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struct sock *nfnl_stash;
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#if IS_ENABLED(CONFIG_NETFILTER_NETLINK_ACCT)
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struct list_head nfnl_acct_list;
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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struct list_head nfct_timeout_list;
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#endif
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#endif
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#ifdef CONFIG_WEXT_CORE
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struct sk_buff_head wext_nlevents;
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#endif
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struct net_generic __rcu *gen;
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struct bpf_prog __rcu *flow_dissector_prog;
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/* Note : following structs are cache line aligned */
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#ifdef CONFIG_XFRM
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struct netns_xfrm xfrm;
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#endif
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#if IS_ENABLED(CONFIG_IP_VS)
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struct netns_ipvs *ipvs;
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#endif
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#if IS_ENABLED(CONFIG_MPLS)
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struct netns_mpls mpls;
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#endif
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#if IS_ENABLED(CONFIG_CAN)
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struct netns_can can;
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#endif
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#ifdef CONFIG_XDP_SOCKETS
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struct netns_xdp xdp;
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#endif
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struct sock *diag_nlsk;
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atomic_t fnhe_genid;
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} __randomize_layout;
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#include <linux/seq_file_net.h>
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/* Init's network namespace */
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extern struct net init_net;
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#ifdef CONFIG_NET_NS
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struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
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struct net *old_net);
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void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
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void net_ns_barrier(void);
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#else /* CONFIG_NET_NS */
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#include <linux/sched.h>
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#include <linux/nsproxy.h>
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static inline struct net *copy_net_ns(unsigned long flags,
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struct user_namespace *user_ns, struct net *old_net)
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{
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if (flags & CLONE_NEWNET)
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return ERR_PTR(-EINVAL);
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return old_net;
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}
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static inline void net_ns_get_ownership(const struct net *net,
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kuid_t *uid, kgid_t *gid)
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{
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*uid = GLOBAL_ROOT_UID;
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*gid = GLOBAL_ROOT_GID;
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}
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static inline void net_ns_barrier(void) {}
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#endif /* CONFIG_NET_NS */
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extern struct list_head net_namespace_list;
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struct net *get_net_ns_by_pid(pid_t pid);
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struct net *get_net_ns_by_fd(int fd);
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#ifdef CONFIG_SYSCTL
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void ipx_register_sysctl(void);
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void ipx_unregister_sysctl(void);
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#else
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#define ipx_register_sysctl()
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#define ipx_unregister_sysctl()
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#endif
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#ifdef CONFIG_NET_NS
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void __put_net(struct net *net);
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static inline struct net *get_net(struct net *net)
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{
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refcount_inc(&net->count);
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return net;
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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/* Used when we know struct net exists but we
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* aren't guaranteed a previous reference count
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* exists. If the reference count is zero this
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* function fails and returns NULL.
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*/
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if (!refcount_inc_not_zero(&net->count))
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net = NULL;
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return net;
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}
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static inline void put_net(struct net *net)
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{
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if (refcount_dec_and_test(&net->count))
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__put_net(net);
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return net1 == net2;
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}
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static inline int check_net(const struct net *net)
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{
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return refcount_read(&net->count) != 0;
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}
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void net_drop_ns(void *);
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#else
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static inline struct net *get_net(struct net *net)
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{
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return net;
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}
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static inline void put_net(struct net *net)
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{
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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return net;
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return 1;
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}
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static inline int check_net(const struct net *net)
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{
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return 1;
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}
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#define net_drop_ns NULL
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#endif
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typedef struct {
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#ifdef CONFIG_NET_NS
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struct net *net;
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#endif
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} possible_net_t;
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static inline void write_pnet(possible_net_t *pnet, struct net *net)
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{
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#ifdef CONFIG_NET_NS
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pnet->net = net;
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#endif
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}
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static inline struct net *read_pnet(const possible_net_t *pnet)
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{
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#ifdef CONFIG_NET_NS
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return pnet->net;
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#else
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return &init_net;
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#endif
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}
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/* Protected by net_rwsem */
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#define for_each_net(VAR) \
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list_for_each_entry(VAR, &net_namespace_list, list)
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#define for_each_net_rcu(VAR) \
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list_for_each_entry_rcu(VAR, &net_namespace_list, list)
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#ifdef CONFIG_NET_NS
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#define __net_init
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#define __net_exit
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#define __net_initdata
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#define __net_initconst
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#else
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#define __net_init __init
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#define __net_exit __ref
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#define __net_initdata __initdata
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#define __net_initconst __initconst
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#endif
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int peernet2id_alloc(struct net *net, struct net *peer);
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int peernet2id(struct net *net, struct net *peer);
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bool peernet_has_id(struct net *net, struct net *peer);
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struct net *get_net_ns_by_id(struct net *net, int id);
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struct pernet_operations {
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struct list_head list;
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/*
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* Below methods are called without any exclusive locks.
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* More than one net may be constructed and destructed
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* in parallel on several cpus. Every pernet_operations
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* have to keep in mind all other pernet_operations and
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* to introduce a locking, if they share common resources.
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*
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* The only time they are called with exclusive lock is
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* from register_pernet_subsys(), unregister_pernet_subsys()
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* register_pernet_device() and unregister_pernet_device().
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*
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* Exit methods using blocking RCU primitives, such as
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* synchronize_rcu(), should be implemented via exit_batch.
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* Then, destruction of a group of net requires single
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* synchronize_rcu() related to these pernet_operations,
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* instead of separate synchronize_rcu() for every net.
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* Please, avoid synchronize_rcu() at all, where it's possible.
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*/
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int (*init)(struct net *net);
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void (*exit)(struct net *net);
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void (*exit_batch)(struct list_head *net_exit_list);
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unsigned int *id;
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size_t size;
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};
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/*
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* Use these carefully. If you implement a network device and it
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* needs per network namespace operations use device pernet operations,
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* otherwise use pernet subsys operations.
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*
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* Network interfaces need to be removed from a dying netns _before_
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* subsys notifiers can be called, as most of the network code cleanup
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* (which is done from subsys notifiers) runs with the assumption that
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* dev_remove_pack has been called so no new packets will arrive during
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* and after the cleanup functions have been called. dev_remove_pack
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* is not per namespace so instead the guarantee of no more packets
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* arriving in a network namespace is provided by ensuring that all
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* network devices and all sockets have left the network namespace
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* before the cleanup methods are called.
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*
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* For the longest time the ipv4 icmp code was registered as a pernet
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* device which caused kernel oops, and panics during network
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* namespace cleanup. So please don't get this wrong.
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*/
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int register_pernet_subsys(struct pernet_operations *);
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void unregister_pernet_subsys(struct pernet_operations *);
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int register_pernet_device(struct pernet_operations *);
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void unregister_pernet_device(struct pernet_operations *);
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struct ctl_table;
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struct ctl_table_header;
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#ifdef CONFIG_SYSCTL
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int net_sysctl_init(void);
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struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
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struct ctl_table *table);
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void unregister_net_sysctl_table(struct ctl_table_header *header);
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#else
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static inline int net_sysctl_init(void) { return 0; }
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static inline struct ctl_table_header *register_net_sysctl(struct net *net,
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const char *path, struct ctl_table *table)
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{
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return NULL;
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}
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static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
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{
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}
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#endif
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static inline int rt_genid_ipv4(struct net *net)
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{
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return atomic_read(&net->ipv4.rt_genid);
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}
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static inline void rt_genid_bump_ipv4(struct net *net)
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{
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atomic_inc(&net->ipv4.rt_genid);
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}
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extern void (*__fib6_flush_trees)(struct net *net);
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static inline void rt_genid_bump_ipv6(struct net *net)
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{
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if (__fib6_flush_trees)
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__fib6_flush_trees(net);
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}
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#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
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static inline struct netns_ieee802154_lowpan *
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net_ieee802154_lowpan(struct net *net)
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{
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return &net->ieee802154_lowpan;
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}
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#endif
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/* For callers who don't really care about whether it's IPv4 or IPv6 */
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static inline void rt_genid_bump_all(struct net *net)
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{
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rt_genid_bump_ipv4(net);
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rt_genid_bump_ipv6(net);
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}
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static inline int fnhe_genid(struct net *net)
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{
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return atomic_read(&net->fnhe_genid);
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}
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static inline void fnhe_genid_bump(struct net *net)
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{
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atomic_inc(&net->fnhe_genid);
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}
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#endif /* __NET_NET_NAMESPACE_H */
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