linux-stable/include/net/net_namespace.h
Jiri Pirko 2034d90ae4 net: treat possible_net_t net pointer as an RCU one and add read_pnet_rcu()
Make the net pointer stored in possible_net_t structure annotated as
an RCU pointer. Change the access helpers to treat it as such.
Introduce read_pnet_rcu() helper to allow caller to dereference
the net pointer under RCU read lock.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-10-18 09:23:01 +01:00

557 lines
14 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Operations on the network namespace
*/
#ifndef __NET_NET_NAMESPACE_H
#define __NET_NET_NAMESPACE_H
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include <linux/list.h>
#include <linux/sysctl.h>
#include <linux/uidgid.h>
#include <net/flow.h>
#include <net/netns/core.h>
#include <net/netns/mib.h>
#include <net/netns/unix.h>
#include <net/netns/packet.h>
#include <net/netns/ipv4.h>
#include <net/netns/ipv6.h>
#include <net/netns/nexthop.h>
#include <net/netns/ieee802154_6lowpan.h>
#include <net/netns/sctp.h>
#include <net/netns/netfilter.h>
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
#include <net/netns/conntrack.h>
#endif
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
#include <net/netns/flow_table.h>
#endif
#include <net/netns/nftables.h>
#include <net/netns/xfrm.h>
#include <net/netns/mpls.h>
#include <net/netns/can.h>
#include <net/netns/xdp.h>
#include <net/netns/smc.h>
#include <net/netns/bpf.h>
#include <net/netns/mctp.h>
#include <net/net_trackers.h>
#include <linux/ns_common.h>
#include <linux/idr.h>
#include <linux/skbuff.h>
#include <linux/notifier.h>
#include <linux/xarray.h>
struct user_namespace;
struct proc_dir_entry;
struct net_device;
struct sock;
struct ctl_table_header;
struct net_generic;
struct uevent_sock;
struct netns_ipvs;
struct bpf_prog;
#define NETDEV_HASHBITS 8
#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
struct net {
/* First cache line can be often dirtied.
* Do not place here read-mostly fields.
*/
refcount_t passive; /* To decide when the network
* namespace should be freed.
*/
spinlock_t rules_mod_lock;
atomic_t dev_unreg_count;
unsigned int dev_base_seq; /* protected by rtnl_mutex */
u32 ifindex;
spinlock_t nsid_lock;
atomic_t fnhe_genid;
struct list_head list; /* list of network namespaces */
struct list_head exit_list; /* To linked to call pernet exit
* methods on dead net (
* pernet_ops_rwsem read locked),
* or to unregister pernet ops
* (pernet_ops_rwsem write locked).
*/
struct llist_node cleanup_list; /* namespaces on death row */
#ifdef CONFIG_KEYS
struct key_tag *key_domain; /* Key domain of operation tag */
#endif
struct user_namespace *user_ns; /* Owning user namespace */
struct ucounts *ucounts;
struct idr netns_ids;
struct ns_common ns;
struct ref_tracker_dir refcnt_tracker;
struct ref_tracker_dir notrefcnt_tracker; /* tracker for objects not
* refcounted against netns
*/
struct list_head dev_base_head;
struct proc_dir_entry *proc_net;
struct proc_dir_entry *proc_net_stat;
#ifdef CONFIG_SYSCTL
struct ctl_table_set sysctls;
#endif
struct sock *rtnl; /* rtnetlink socket */
struct sock *genl_sock;
struct uevent_sock *uevent_sock; /* uevent socket */
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
struct xarray dev_by_index;
struct raw_notifier_head netdev_chain;
/* Note that @hash_mix can be read millions times per second,
* it is critical that it is on a read_mostly cache line.
*/
u32 hash_mix;
struct net_device *loopback_dev; /* The loopback */
/* core fib_rules */
struct list_head rules_ops;
struct netns_core core;
struct netns_mib mib;
struct netns_packet packet;
#if IS_ENABLED(CONFIG_UNIX)
struct netns_unix unx;
#endif
struct netns_nexthop nexthop;
struct netns_ipv4 ipv4;
#if IS_ENABLED(CONFIG_IPV6)
struct netns_ipv6 ipv6;
#endif
#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
struct netns_ieee802154_lowpan ieee802154_lowpan;
#endif
#if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
struct netns_sctp sctp;
#endif
#ifdef CONFIG_NETFILTER
struct netns_nf nf;
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct netns_ct ct;
#endif
#if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
struct netns_nftables nft;
#endif
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
struct netns_ft ft;
#endif
#endif
#ifdef CONFIG_WEXT_CORE
struct sk_buff_head wext_nlevents;
#endif
struct net_generic __rcu *gen;
/* Used to store attached BPF programs */
struct netns_bpf bpf;
/* Note : following structs are cache line aligned */
#ifdef CONFIG_XFRM
struct netns_xfrm xfrm;
#endif
u64 net_cookie; /* written once */
#if IS_ENABLED(CONFIG_IP_VS)
struct netns_ipvs *ipvs;
#endif
#if IS_ENABLED(CONFIG_MPLS)
struct netns_mpls mpls;
#endif
#if IS_ENABLED(CONFIG_CAN)
struct netns_can can;
#endif
#ifdef CONFIG_XDP_SOCKETS
struct netns_xdp xdp;
#endif
#if IS_ENABLED(CONFIG_MCTP)
struct netns_mctp mctp;
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
struct sock *crypto_nlsk;
#endif
struct sock *diag_nlsk;
#if IS_ENABLED(CONFIG_SMC)
struct netns_smc smc;
#endif
} __randomize_layout;
#include <linux/seq_file_net.h>
/* Init's network namespace */
extern struct net init_net;
#ifdef CONFIG_NET_NS
struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
struct net *old_net);
void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
void net_ns_barrier(void);
struct ns_common *get_net_ns(struct ns_common *ns);
struct net *get_net_ns_by_fd(int fd);
#else /* CONFIG_NET_NS */
#include <linux/sched.h>
#include <linux/nsproxy.h>
static inline struct net *copy_net_ns(unsigned long flags,
struct user_namespace *user_ns, struct net *old_net)
{
if (flags & CLONE_NEWNET)
return ERR_PTR(-EINVAL);
return old_net;
}
static inline void net_ns_get_ownership(const struct net *net,
kuid_t *uid, kgid_t *gid)
{
*uid = GLOBAL_ROOT_UID;
*gid = GLOBAL_ROOT_GID;
}
static inline void net_ns_barrier(void) {}
static inline struct ns_common *get_net_ns(struct ns_common *ns)
{
return ERR_PTR(-EINVAL);
}
static inline struct net *get_net_ns_by_fd(int fd)
{
return ERR_PTR(-EINVAL);
}
#endif /* CONFIG_NET_NS */
extern struct list_head net_namespace_list;
struct net *get_net_ns_by_pid(pid_t pid);
#ifdef CONFIG_SYSCTL
void ipx_register_sysctl(void);
void ipx_unregister_sysctl(void);
#else
#define ipx_register_sysctl()
#define ipx_unregister_sysctl()
#endif
#ifdef CONFIG_NET_NS
void __put_net(struct net *net);
/* Try using get_net_track() instead */
static inline struct net *get_net(struct net *net)
{
refcount_inc(&net->ns.count);
return net;
}
static inline struct net *maybe_get_net(struct net *net)
{
/* Used when we know struct net exists but we
* aren't guaranteed a previous reference count
* exists. If the reference count is zero this
* function fails and returns NULL.
*/
if (!refcount_inc_not_zero(&net->ns.count))
net = NULL;
return net;
}
/* Try using put_net_track() instead */
static inline void put_net(struct net *net)
{
if (refcount_dec_and_test(&net->ns.count))
__put_net(net);
}
static inline
int net_eq(const struct net *net1, const struct net *net2)
{
return net1 == net2;
}
static inline int check_net(const struct net *net)
{
return refcount_read(&net->ns.count) != 0;
}
void net_drop_ns(void *);
#else
static inline struct net *get_net(struct net *net)
{
return net;
}
static inline void put_net(struct net *net)
{
}
static inline struct net *maybe_get_net(struct net *net)
{
return net;
}
static inline
int net_eq(const struct net *net1, const struct net *net2)
{
return 1;
}
static inline int check_net(const struct net *net)
{
return 1;
}
#define net_drop_ns NULL
#endif
static inline void __netns_tracker_alloc(struct net *net,
netns_tracker *tracker,
bool refcounted,
gfp_t gfp)
{
#ifdef CONFIG_NET_NS_REFCNT_TRACKER
ref_tracker_alloc(refcounted ? &net->refcnt_tracker :
&net->notrefcnt_tracker,
tracker, gfp);
#endif
}
static inline void netns_tracker_alloc(struct net *net, netns_tracker *tracker,
gfp_t gfp)
{
__netns_tracker_alloc(net, tracker, true, gfp);
}
static inline void __netns_tracker_free(struct net *net,
netns_tracker *tracker,
bool refcounted)
{
#ifdef CONFIG_NET_NS_REFCNT_TRACKER
ref_tracker_free(refcounted ? &net->refcnt_tracker :
&net->notrefcnt_tracker, tracker);
#endif
}
static inline struct net *get_net_track(struct net *net,
netns_tracker *tracker, gfp_t gfp)
{
get_net(net);
netns_tracker_alloc(net, tracker, gfp);
return net;
}
static inline void put_net_track(struct net *net, netns_tracker *tracker)
{
__netns_tracker_free(net, tracker, true);
put_net(net);
}
typedef struct {
#ifdef CONFIG_NET_NS
struct net __rcu *net;
#endif
} possible_net_t;
static inline void write_pnet(possible_net_t *pnet, struct net *net)
{
#ifdef CONFIG_NET_NS
rcu_assign_pointer(pnet->net, net);
#endif
}
static inline struct net *read_pnet(const possible_net_t *pnet)
{
#ifdef CONFIG_NET_NS
return rcu_dereference_protected(pnet->net, true);
#else
return &init_net;
#endif
}
static inline struct net *read_pnet_rcu(possible_net_t *pnet)
{
#ifdef CONFIG_NET_NS
return rcu_dereference(pnet->net);
#else
return &init_net;
#endif
}
/* Protected by net_rwsem */
#define for_each_net(VAR) \
list_for_each_entry(VAR, &net_namespace_list, list)
#define for_each_net_continue_reverse(VAR) \
list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
#define for_each_net_rcu(VAR) \
list_for_each_entry_rcu(VAR, &net_namespace_list, list)
#ifdef CONFIG_NET_NS
#define __net_init
#define __net_exit
#define __net_initdata
#define __net_initconst
#else
#define __net_init __init
#define __net_exit __ref
#define __net_initdata __initdata
#define __net_initconst __initconst
#endif
int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp);
int peernet2id(const struct net *net, struct net *peer);
bool peernet_has_id(const struct net *net, struct net *peer);
struct net *get_net_ns_by_id(const struct net *net, int id);
struct pernet_operations {
struct list_head list;
/*
* Below methods are called without any exclusive locks.
* More than one net may be constructed and destructed
* in parallel on several cpus. Every pernet_operations
* have to keep in mind all other pernet_operations and
* to introduce a locking, if they share common resources.
*
* The only time they are called with exclusive lock is
* from register_pernet_subsys(), unregister_pernet_subsys()
* register_pernet_device() and unregister_pernet_device().
*
* Exit methods using blocking RCU primitives, such as
* synchronize_rcu(), should be implemented via exit_batch.
* Then, destruction of a group of net requires single
* synchronize_rcu() related to these pernet_operations,
* instead of separate synchronize_rcu() for every net.
* Please, avoid synchronize_rcu() at all, where it's possible.
*
* Note that a combination of pre_exit() and exit() can
* be used, since a synchronize_rcu() is guaranteed between
* the calls.
*/
int (*init)(struct net *net);
void (*pre_exit)(struct net *net);
void (*exit)(struct net *net);
void (*exit_batch)(struct list_head *net_exit_list);
unsigned int *id;
size_t size;
};
/*
* Use these carefully. If you implement a network device and it
* needs per network namespace operations use device pernet operations,
* otherwise use pernet subsys operations.
*
* Network interfaces need to be removed from a dying netns _before_
* subsys notifiers can be called, as most of the network code cleanup
* (which is done from subsys notifiers) runs with the assumption that
* dev_remove_pack has been called so no new packets will arrive during
* and after the cleanup functions have been called. dev_remove_pack
* is not per namespace so instead the guarantee of no more packets
* arriving in a network namespace is provided by ensuring that all
* network devices and all sockets have left the network namespace
* before the cleanup methods are called.
*
* For the longest time the ipv4 icmp code was registered as a pernet
* device which caused kernel oops, and panics during network
* namespace cleanup. So please don't get this wrong.
*/
int register_pernet_subsys(struct pernet_operations *);
void unregister_pernet_subsys(struct pernet_operations *);
int register_pernet_device(struct pernet_operations *);
void unregister_pernet_device(struct pernet_operations *);
struct ctl_table;
#define register_net_sysctl(net, path, table) \
register_net_sysctl_sz(net, path, table, ARRAY_SIZE(table))
#ifdef CONFIG_SYSCTL
int net_sysctl_init(void);
struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,
struct ctl_table *table, size_t table_size);
void unregister_net_sysctl_table(struct ctl_table_header *header);
#else
static inline int net_sysctl_init(void) { return 0; }
static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,
const char *path, struct ctl_table *table, size_t table_size)
{
return NULL;
}
static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
{
}
#endif
static inline int rt_genid_ipv4(const struct net *net)
{
return atomic_read(&net->ipv4.rt_genid);
}
#if IS_ENABLED(CONFIG_IPV6)
static inline int rt_genid_ipv6(const struct net *net)
{
return atomic_read(&net->ipv6.fib6_sernum);
}
#endif
static inline void rt_genid_bump_ipv4(struct net *net)
{
atomic_inc(&net->ipv4.rt_genid);
}
extern void (*__fib6_flush_trees)(struct net *net);
static inline void rt_genid_bump_ipv6(struct net *net)
{
if (__fib6_flush_trees)
__fib6_flush_trees(net);
}
#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
static inline struct netns_ieee802154_lowpan *
net_ieee802154_lowpan(struct net *net)
{
return &net->ieee802154_lowpan;
}
#endif
/* For callers who don't really care about whether it's IPv4 or IPv6 */
static inline void rt_genid_bump_all(struct net *net)
{
rt_genid_bump_ipv4(net);
rt_genid_bump_ipv6(net);
}
static inline int fnhe_genid(const struct net *net)
{
return atomic_read(&net->fnhe_genid);
}
static inline void fnhe_genid_bump(struct net *net)
{
atomic_inc(&net->fnhe_genid);
}
#ifdef CONFIG_NET
void net_ns_init(void);
#else
static inline void net_ns_init(void) {}
#endif
#endif /* __NET_NET_NAMESPACE_H */