/* 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/dccp.h>
#include <net/netns/netfilter.h>
#include <net/netns/x_tables.h>
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
#include <net/netns/conntrack.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 <linux/ns_common.h>
#include <linux/idr.h>
#include <linux/skbuff.h>
#include <linux/notifier.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.
                                                 */
        refcount_t              count;          /* To decided when the network
                                                 *  namespace should be shut down.
                                                 */
        spinlock_t              rules_mod_lock;

        unsigned int            dev_unreg_count;

        unsigned int            dev_base_seq;   /* protected by rtnl_mutex */
        int                     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 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 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;
        struct netns_unix       unx;
        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
#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
        struct netns_dccp       dccp;
#endif
#ifdef CONFIG_NETFILTER
        struct netns_nf         nf;
        struct netns_xt         xt;
#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_DEFRAG_IPV6)
        struct netns_nf_frag    nf_frag;
        struct ctl_table_header *nf_frag_frags_hdr;
#endif
        struct sock             *nfnl;
        struct sock             *nfnl_stash;
#if IS_ENABLED(CONFIG_NETFILTER_NETLINK_ACCT)
        struct list_head        nfnl_acct_list;
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
        struct list_head        nfct_timeout_list;
#endif
#endif
#ifdef CONFIG_WEXT_CORE
        struct sk_buff_head     wext_nlevents;
#endif
        struct net_generic __rcu        *gen;

        struct bpf_prog __rcu   *flow_dissector_prog;

        /* Note : following structs are cache line aligned */
#ifdef CONFIG_XFRM
        struct netns_xfrm       xfrm;
#endif
#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_CRYPTO_USER)
        struct sock             *crypto_nlsk;
#endif
        struct sock             *diag_nlsk;
} __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);
#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) {}
#endif /* CONFIG_NET_NS */


extern struct list_head net_namespace_list;

struct net *get_net_ns_by_pid(pid_t pid);
struct net *get_net_ns_by_fd(int fd);

#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);

static inline struct net *get_net(struct net *net)
{
        refcount_inc(&net->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->count))
                net = NULL;
        return net;
}

static inline void put_net(struct net *net)
{
        if (refcount_dec_and_test(&net->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->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


typedef struct {
#ifdef CONFIG_NET_NS
        struct net *net;
#endif
} possible_net_t;

static inline void write_pnet(possible_net_t *pnet, struct net *net)
{
#ifdef CONFIG_NET_NS
        pnet->net = net;
#endif
}

static inline struct net *read_pnet(const possible_net_t *pnet)
{
#ifdef CONFIG_NET_NS
        return 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;
struct ctl_table_header;

#ifdef CONFIG_SYSCTL
int net_sysctl_init(void);
struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
                                             struct ctl_table *table);
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(struct net *net,
        const char *path, struct ctl_table *table)
{
        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);
}

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);
}

#endif /* __NET_NET_NAMESPACE_H */