/* SPDX-License-Identifier: GPL-2.0 */
/* IP Virtual Server
 * data structure and functionality definitions
 */

#ifndef _NET_IP_VS_H
#define _NET_IP_VS_H

#include <linux/ip_vs.h>                /* definitions shared with userland */

#include <asm/types.h>                  /* for __uXX types */

#include <linux/list.h>                 /* for struct list_head */
#include <linux/spinlock.h>             /* for struct rwlock_t */
#include <linux/atomic.h>               /* for struct atomic_t */
#include <linux/refcount.h>             /* for struct refcount_t */
#include <linux/workqueue.h>

#include <linux/compiler.h>
#include <linux/timer.h>
#include <linux/bug.h>

#include <net/checksum.h>
#include <linux/netfilter.h>            /* for union nf_inet_addr */
#include <linux/ip.h>
#include <linux/ipv6.h>                 /* for struct ipv6hdr */
#include <net/ipv6.h>
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif
#include <net/net_namespace.h>          /* Netw namespace */
#include <linux/sched/isolation.h>

#define IP_VS_HDR_INVERSE       1
#define IP_VS_HDR_ICMP          2

/* Generic access of ipvs struct */
static inline struct netns_ipvs *net_ipvs(struct net* net)
{
        return net->ipvs;
}

/* Connections' size value needed by ip_vs_ctl.c */
extern int ip_vs_conn_tab_size;

extern struct mutex __ip_vs_mutex;

struct ip_vs_iphdr {
        int hdr_flags;  /* ipvs flags */
        __u32 off;      /* Where IP or IPv4 header starts */
        __u32 len;      /* IPv4 simply where L4 starts
                         * IPv6 where L4 Transport Header starts */
        __u16 fragoffs; /* IPv6 fragment offset, 0 if first frag (or not frag)*/
        __s16 protocol;
        __s32 flags;
        union nf_inet_addr saddr;
        union nf_inet_addr daddr;
};

static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset,
                                      int len, void *buffer)
{
        return skb_header_pointer(skb, offset, len, buffer);
}

/* This function handles filling *ip_vs_iphdr, both for IPv4 and IPv6.
 * IPv6 requires some extra work, as finding proper header position,
 * depend on the IPv6 extension headers.
 */
static inline int
ip_vs_fill_iph_skb_off(int af, const struct sk_buff *skb, int offset,
                       int hdr_flags, struct ip_vs_iphdr *iphdr)
{
        iphdr->hdr_flags = hdr_flags;
        iphdr->off = offset;

#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6) {
                struct ipv6hdr _iph;
                const struct ipv6hdr *iph = skb_header_pointer(
                        skb, offset, sizeof(_iph), &_iph);
                if (!iph)
                        return 0;

                iphdr->saddr.in6 = iph->saddr;
                iphdr->daddr.in6 = iph->daddr;
                /* ipv6_find_hdr() updates len, flags */
                iphdr->len       = offset;
                iphdr->flags     = 0;
                iphdr->protocol  = ipv6_find_hdr(skb, &iphdr->len, -1,
                                                 &iphdr->fragoffs,
                                                 &iphdr->flags);
                if (iphdr->protocol < 0)
                        return 0;
        } else
#endif
        {
                struct iphdr _iph;
                const struct iphdr *iph = skb_header_pointer(
                        skb, offset, sizeof(_iph), &_iph);
                if (!iph)
                        return 0;

                iphdr->len      = offset + iph->ihl * 4;
                iphdr->fragoffs = 0;
                iphdr->protocol = iph->protocol;
                iphdr->saddr.ip = iph->saddr;
                iphdr->daddr.ip = iph->daddr;
        }

        return 1;
}

static inline int
ip_vs_fill_iph_skb_icmp(int af, const struct sk_buff *skb, int offset,
                        bool inverse, struct ip_vs_iphdr *iphdr)
{
        int hdr_flags = IP_VS_HDR_ICMP;

        if (inverse)
                hdr_flags |= IP_VS_HDR_INVERSE;

        return ip_vs_fill_iph_skb_off(af, skb, offset, hdr_flags, iphdr);
}

static inline int
ip_vs_fill_iph_skb(int af, const struct sk_buff *skb, bool inverse,
                   struct ip_vs_iphdr *iphdr)
{
        int hdr_flags = 0;

        if (inverse)
                hdr_flags |= IP_VS_HDR_INVERSE;

        return ip_vs_fill_iph_skb_off(af, skb, skb_network_offset(skb),
                                      hdr_flags, iphdr);
}

static inline bool
ip_vs_iph_inverse(const struct ip_vs_iphdr *iph)
{
        return !!(iph->hdr_flags & IP_VS_HDR_INVERSE);
}

static inline bool
ip_vs_iph_icmp(const struct ip_vs_iphdr *iph)
{
        return !!(iph->hdr_flags & IP_VS_HDR_ICMP);
}

static inline void ip_vs_addr_copy(int af, union nf_inet_addr *dst,
                                   const union nf_inet_addr *src)
{
#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6)
                dst->in6 = src->in6;
        else
#endif
        dst->ip = src->ip;
}

static inline void ip_vs_addr_set(int af, union nf_inet_addr *dst,
                                  const union nf_inet_addr *src)
{
#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6) {
                dst->in6 = src->in6;
                return;
        }
#endif
        dst->ip = src->ip;
        dst->all[1] = 0;
        dst->all[2] = 0;
        dst->all[3] = 0;
}

static inline int ip_vs_addr_equal(int af, const union nf_inet_addr *a,
                                   const union nf_inet_addr *b)
{
#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6)
                return ipv6_addr_equal(&a->in6, &b->in6);
#endif
        return a->ip == b->ip;
}

#ifdef CONFIG_IP_VS_DEBUG
#include <linux/net.h>

int ip_vs_get_debug_level(void);

static inline const char *ip_vs_dbg_addr(int af, char *buf, size_t buf_len,
                                         const union nf_inet_addr *addr,
                                         int *idx)
{
        int len;
#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6)
                len = snprintf(&buf[*idx], buf_len - *idx, "[%pI6c]",
                               &addr->in6) + 1;
        else
#endif
                len = snprintf(&buf[*idx], buf_len - *idx, "%pI4",
                               &addr->ip) + 1;

        *idx += len;
        BUG_ON(*idx > buf_len + 1);
        return &buf[*idx - len];
}

#define IP_VS_DBG_BUF(level, msg, ...)                                  \
        do {                                                            \
                char ip_vs_dbg_buf[160];                                \
                int ip_vs_dbg_idx = 0;                                  \
                if (level <= ip_vs_get_debug_level())                   \
                        printk(KERN_DEBUG pr_fmt(msg), ##__VA_ARGS__);  \
        } while (0)
#define IP_VS_ERR_BUF(msg...)                                           \
        do {                                                            \
                char ip_vs_dbg_buf[160];                                \
                int ip_vs_dbg_idx = 0;                                  \
                pr_err(msg);                                            \
        } while (0)

/* Only use from within IP_VS_DBG_BUF() or IP_VS_ERR_BUF macros */
#define IP_VS_DBG_ADDR(af, addr)                                        \
        ip_vs_dbg_addr(af, ip_vs_dbg_buf,                               \
                       sizeof(ip_vs_dbg_buf), addr,                     \
                       &ip_vs_dbg_idx)

#define IP_VS_DBG(level, msg, ...)                                      \
        do {                                                            \
                if (level <= ip_vs_get_debug_level())                   \
                        printk(KERN_DEBUG pr_fmt(msg), ##__VA_ARGS__);  \
        } while (0)
#define IP_VS_DBG_RL(msg, ...)                                          \
        do {                                                            \
                if (net_ratelimit())                                    \
                        printk(KERN_DEBUG pr_fmt(msg), ##__VA_ARGS__);  \
        } while (0)
#define IP_VS_DBG_PKT(level, af, pp, skb, ofs, msg)                     \
        do {                                                            \
                if (level <= ip_vs_get_debug_level())                   \
                        pp->debug_packet(af, pp, skb, ofs, msg);        \
        } while (0)
#define IP_VS_DBG_RL_PKT(level, af, pp, skb, ofs, msg)                  \
        do {                                                            \
                if (level <= ip_vs_get_debug_level() &&                 \
                    net_ratelimit())                                    \
                        pp->debug_packet(af, pp, skb, ofs, msg);        \
        } while (0)
#else   /* NO DEBUGGING at ALL */
#define IP_VS_DBG_BUF(level, msg...)  do {} while (0)
#define IP_VS_ERR_BUF(msg...)  do {} while (0)
#define IP_VS_DBG(level, msg...)  do {} while (0)
#define IP_VS_DBG_RL(msg...)  do {} while (0)
#define IP_VS_DBG_PKT(level, af, pp, skb, ofs, msg)     do {} while (0)
#define IP_VS_DBG_RL_PKT(level, af, pp, skb, ofs, msg)  do {} while (0)
#endif

#define IP_VS_BUG() BUG()
#define IP_VS_ERR_RL(msg, ...)                                          \
        do {                                                            \
                if (net_ratelimit())                                    \
                        pr_err(msg, ##__VA_ARGS__);                     \
        } while (0)

/* The port number of FTP service (in network order). */
#define FTPPORT  cpu_to_be16(21)
#define FTPDATA  cpu_to_be16(20)

/* TCP State Values */
enum {
        IP_VS_TCP_S_NONE = 0,
        IP_VS_TCP_S_ESTABLISHED,
        IP_VS_TCP_S_SYN_SENT,
        IP_VS_TCP_S_SYN_RECV,
        IP_VS_TCP_S_FIN_WAIT,
        IP_VS_TCP_S_TIME_WAIT,
        IP_VS_TCP_S_CLOSE,
        IP_VS_TCP_S_CLOSE_WAIT,
        IP_VS_TCP_S_LAST_ACK,
        IP_VS_TCP_S_LISTEN,
        IP_VS_TCP_S_SYNACK,
        IP_VS_TCP_S_LAST
};

/* UDP State Values */
enum {
        IP_VS_UDP_S_NORMAL,
        IP_VS_UDP_S_LAST,
};

/* ICMP State Values */
enum {
        IP_VS_ICMP_S_NORMAL,
        IP_VS_ICMP_S_LAST,
};

/* SCTP State Values */
enum ip_vs_sctp_states {
        IP_VS_SCTP_S_NONE,
        IP_VS_SCTP_S_INIT1,
        IP_VS_SCTP_S_INIT,
        IP_VS_SCTP_S_COOKIE_SENT,
        IP_VS_SCTP_S_COOKIE_REPLIED,
        IP_VS_SCTP_S_COOKIE_WAIT,
        IP_VS_SCTP_S_COOKIE,
        IP_VS_SCTP_S_COOKIE_ECHOED,
        IP_VS_SCTP_S_ESTABLISHED,
        IP_VS_SCTP_S_SHUTDOWN_SENT,
        IP_VS_SCTP_S_SHUTDOWN_RECEIVED,
        IP_VS_SCTP_S_SHUTDOWN_ACK_SENT,
        IP_VS_SCTP_S_REJECTED,
        IP_VS_SCTP_S_CLOSED,
        IP_VS_SCTP_S_LAST
};

/* Connection templates use bits from state */
#define IP_VS_CTPL_S_NONE               0x0000
#define IP_VS_CTPL_S_ASSURED            0x0001
#define IP_VS_CTPL_S_LAST               0x0002

/* Delta sequence info structure
 * Each ip_vs_conn has 2 (output AND input seq. changes).
 * Only used in the VS/NAT.
 */
struct ip_vs_seq {
        __u32                   init_seq;       /* Add delta from this seq */
        __u32                   delta;          /* Delta in sequence numbers */
        __u32                   previous_delta; /* Delta in sequence numbers
                                                 * before last resized pkt */
};

/* counters per cpu */
struct ip_vs_counters {
        u64_stats_t     conns;          /* connections scheduled */
        u64_stats_t     inpkts;         /* incoming packets */
        u64_stats_t     outpkts;        /* outgoing packets */
        u64_stats_t     inbytes;        /* incoming bytes */
        u64_stats_t     outbytes;       /* outgoing bytes */
};
/* Stats per cpu */
struct ip_vs_cpu_stats {
        struct ip_vs_counters   cnt;
        struct u64_stats_sync   syncp;
};

/* Default nice for estimator kthreads */
#define IPVS_EST_NICE           0

/* IPVS statistics objects */
struct ip_vs_estimator {
        struct hlist_node       list;

        u64                     last_inbytes;
        u64                     last_outbytes;
        u64                     last_conns;
        u64                     last_inpkts;
        u64                     last_outpkts;

        u64                     cps;
        u64                     inpps;
        u64                     outpps;
        u64                     inbps;
        u64                     outbps;

        s32                     ktid:16,        /* kthread ID, -1=temp list */
                                ktrow:8,        /* row/tick ID for kthread */
                                ktcid:8;        /* chain ID for kthread tick */
};

/*
 * IPVS statistics object, 64-bit kernel version of struct ip_vs_stats_user
 */
struct ip_vs_kstats {
        u64                     conns;          /* connections scheduled */
        u64                     inpkts;         /* incoming packets */
        u64                     outpkts;        /* outgoing packets */
        u64                     inbytes;        /* incoming bytes */
        u64                     outbytes;       /* outgoing bytes */

        u64                     cps;            /* current connection rate */
        u64                     inpps;          /* current in packet rate */
        u64                     outpps;         /* current out packet rate */
        u64                     inbps;          /* current in byte rate */
        u64                     outbps;         /* current out byte rate */
};

struct ip_vs_stats {
        struct ip_vs_kstats     kstats;         /* kernel statistics */
        struct ip_vs_estimator  est;            /* estimator */
        struct ip_vs_cpu_stats __percpu *cpustats;      /* per cpu counters */
        spinlock_t              lock;           /* spin lock */
        struct ip_vs_kstats     kstats0;        /* reset values */
};

struct ip_vs_stats_rcu {
        struct ip_vs_stats      s;
        struct rcu_head         rcu_head;
};

int ip_vs_stats_init_alloc(struct ip_vs_stats *s);
struct ip_vs_stats *ip_vs_stats_alloc(void);
void ip_vs_stats_release(struct ip_vs_stats *stats);
void ip_vs_stats_free(struct ip_vs_stats *stats);

/* Process estimators in multiple timer ticks (20/50/100, see ktrow) */
#define IPVS_EST_NTICKS         50
/* Estimation uses a 2-second period containing ticks (in jiffies) */
#define IPVS_EST_TICK           ((2 * HZ) / IPVS_EST_NTICKS)

/* Limit of CPU load per kthread (8 for 12.5%), ratio of CPU capacity (1/C).
 * Value of 4 and above ensures kthreads will take work without exceeding
 * the CPU capacity under different circumstances.
 */
#define IPVS_EST_LOAD_DIVISOR   8

/* Kthreads should not have work that exceeds the CPU load above 50% */
#define IPVS_EST_CPU_KTHREADS   (IPVS_EST_LOAD_DIVISOR / 2)

/* Desired number of chains per timer tick (chain load factor in 100us units),
 * 48=4.8ms of 40ms tick (12% CPU usage):
 * 2 sec * 1000 ms in sec * 10 (100us in ms) / 8 (12.5%) / 50
 */
#define IPVS_EST_CHAIN_FACTOR   \
        ALIGN_DOWN(2 * 1000 * 10 / IPVS_EST_LOAD_DIVISOR / IPVS_EST_NTICKS, 8)

/* Compiled number of chains per tick
 * The defines should match cond_resched_rcu
 */
#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
#define IPVS_EST_TICK_CHAINS    IPVS_EST_CHAIN_FACTOR
#else
#define IPVS_EST_TICK_CHAINS    1
#endif

#if IPVS_EST_NTICKS > 127
#error Too many timer ticks for ktrow
#endif

/* Multiple chains processed in same tick */
struct ip_vs_est_tick_data {
        struct rcu_head         rcu_head;
        struct hlist_head       chains[IPVS_EST_TICK_CHAINS];
        DECLARE_BITMAP(present, IPVS_EST_TICK_CHAINS);
        DECLARE_BITMAP(full, IPVS_EST_TICK_CHAINS);
        int                     chain_len[IPVS_EST_TICK_CHAINS];
};

/* Context for estimation kthread */
struct ip_vs_est_kt_data {
        struct netns_ipvs       *ipvs;
        struct task_struct      *task;          /* task if running */
        struct ip_vs_est_tick_data __rcu *ticks[IPVS_EST_NTICKS];
        DECLARE_BITMAP(avail, IPVS_EST_NTICKS); /* tick has space for ests */
        unsigned long           est_timer;      /* estimation timer (jiffies) */
        struct ip_vs_stats      *calc_stats;    /* Used for calculation */
        int                     tick_len[IPVS_EST_NTICKS];      /* est count */
        int                     id;             /* ktid per netns */
        int                     chain_max;      /* max ests per tick chain */
        int                     tick_max;       /* max ests per tick */
        int                     est_count;      /* attached ests to kthread */
        int                     est_max_count;  /* max ests per kthread */
        int                     add_row;        /* row for new ests */
        int                     est_row;        /* estimated row */
};

struct dst_entry;
struct iphdr;
struct ip_vs_conn;
struct ip_vs_app;
struct sk_buff;
struct ip_vs_proto_data;

struct ip_vs_protocol {
        struct ip_vs_protocol   *next;
        char                    *name;
        u16                     protocol;
        u16                     num_states;
        int                     dont_defrag;

        void (*init)(struct ip_vs_protocol *pp);

        void (*exit)(struct ip_vs_protocol *pp);

        int (*init_netns)(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd);

        void (*exit_netns)(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd);

        int (*conn_schedule)(struct netns_ipvs *ipvs,
                             int af, struct sk_buff *skb,
                             struct ip_vs_proto_data *pd,
                             int *verdict, struct ip_vs_conn **cpp,
                             struct ip_vs_iphdr *iph);

        struct ip_vs_conn *
        (*conn_in_get)(struct netns_ipvs *ipvs,
                       int af,
                       const struct sk_buff *skb,
                       const struct ip_vs_iphdr *iph);

        struct ip_vs_conn *
        (*conn_out_get)(struct netns_ipvs *ipvs,
                        int af,
                        const struct sk_buff *skb,
                        const struct ip_vs_iphdr *iph);

        int (*snat_handler)(struct sk_buff *skb, struct ip_vs_protocol *pp,
                            struct ip_vs_conn *cp, struct ip_vs_iphdr *iph);

        int (*dnat_handler)(struct sk_buff *skb, struct ip_vs_protocol *pp,
                            struct ip_vs_conn *cp, struct ip_vs_iphdr *iph);

        const char *(*state_name)(int state);

        void (*state_transition)(struct ip_vs_conn *cp, int direction,
                                 const struct sk_buff *skb,
                                 struct ip_vs_proto_data *pd);

        int (*register_app)(struct netns_ipvs *ipvs, struct ip_vs_app *inc);

        void (*unregister_app)(struct netns_ipvs *ipvs, struct ip_vs_app *inc);

        int (*app_conn_bind)(struct ip_vs_conn *cp);

        void (*debug_packet)(int af, struct ip_vs_protocol *pp,
                             const struct sk_buff *skb,
                             int offset,
                             const char *msg);

        void (*timeout_change)(struct ip_vs_proto_data *pd, int flags);
};

/* protocol data per netns */
struct ip_vs_proto_data {
        struct ip_vs_proto_data *next;
        struct ip_vs_protocol   *pp;
        int                     *timeout_table; /* protocol timeout table */
        atomic_t                appcnt;         /* counter of proto app incs. */
        struct tcp_states_t     *tcp_state_table;
};

struct ip_vs_protocol   *ip_vs_proto_get(unsigned short proto);
struct ip_vs_proto_data *ip_vs_proto_data_get(struct netns_ipvs *ipvs,
                                              unsigned short proto);

struct ip_vs_conn_param {
        struct netns_ipvs               *ipvs;
        const union nf_inet_addr        *caddr;
        const union nf_inet_addr        *vaddr;
        __be16                          cport;
        __be16                          vport;
        __u16                           protocol;
        u16                             af;

        const struct ip_vs_pe           *pe;
        char                            *pe_data;
        __u8                            pe_data_len;
};

/* IP_VS structure allocated for each dynamically scheduled connection */
struct ip_vs_conn {
        struct hlist_node       c_list;         /* hashed list heads */
        /* Protocol, addresses and port numbers */
        __be16                  cport;
        __be16                  dport;
        __be16                  vport;
        u16                     af;             /* address family */
        union nf_inet_addr      caddr;          /* client address */
        union nf_inet_addr      vaddr;          /* virtual address */
        union nf_inet_addr      daddr;          /* destination address */
        volatile __u32          flags;          /* status flags */
        __u16                   protocol;       /* Which protocol (TCP/UDP) */
        __u16                   daf;            /* Address family of the dest */
        struct netns_ipvs       *ipvs;

        /* counter and timer */
        refcount_t              refcnt;         /* reference count */
        struct timer_list       timer;          /* Expiration timer */
        volatile unsigned long  timeout;        /* timeout */

        /* Flags and state transition */
        spinlock_t              lock;           /* lock for state transition */
        volatile __u16          state;          /* state info */
        volatile __u16          old_state;      /* old state, to be used for
                                                 * state transition triggered
                                                 * synchronization
                                                 */
        __u32                   fwmark;         /* Fire wall mark from skb */
        unsigned long           sync_endtime;   /* jiffies + sent_retries */

        /* Control members */
        struct ip_vs_conn       *control;       /* Master control connection */
        atomic_t                n_control;      /* Number of controlled ones */
        struct ip_vs_dest       *dest;          /* real server */
        atomic_t                in_pkts;        /* incoming packet counter */

        /* Packet transmitter for different forwarding methods.  If it
         * mangles the packet, it must return NF_DROP or better NF_STOLEN,
         * otherwise this must be changed to a sk_buff **.
         * NF_ACCEPT can be returned when destination is local.
         */
        int (*packet_xmit)(struct sk_buff *skb, struct ip_vs_conn *cp,
                           struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);

        /* Note: we can group the following members into a structure,
         * in order to save more space, and the following members are
         * only used in VS/NAT anyway
         */
        struct ip_vs_app        *app;           /* bound ip_vs_app object */
        void                    *app_data;      /* Application private data */
        struct_group(sync_conn_opt,
                struct ip_vs_seq  in_seq;       /* incoming seq. struct */
                struct ip_vs_seq  out_seq;      /* outgoing seq. struct */
        );

        const struct ip_vs_pe   *pe;
        char                    *pe_data;
        __u8                    pe_data_len;

        struct rcu_head         rcu_head;
};

/* Extended internal versions of struct ip_vs_service_user and ip_vs_dest_user
 * for IPv6 support.
 *
 * We need these to conveniently pass around service and destination
 * options, but unfortunately, we also need to keep the old definitions to
 * maintain userspace backwards compatibility for the setsockopt interface.
 */
struct ip_vs_service_user_kern {
        /* virtual service addresses */
        u16                     af;
        u16                     protocol;
        union nf_inet_addr      addr;           /* virtual ip address */
        __be16                  port;
        u32                     fwmark;         /* firewall mark of service */

        /* virtual service options */
        char                    *sched_name;
        char                    *pe_name;
        unsigned int            flags;          /* virtual service flags */
        unsigned int            timeout;        /* persistent timeout in sec */
        __be32                  netmask;        /* persistent netmask or plen */
};


struct ip_vs_dest_user_kern {
        /* destination server address */
        union nf_inet_addr      addr;
        __be16                  port;

        /* real server options */
        unsigned int            conn_flags;     /* connection flags */
        int                     weight;         /* destination weight */

        /* thresholds for active connections */
        u32                     u_threshold;    /* upper threshold */
        u32                     l_threshold;    /* lower threshold */

        /* Address family of addr */
        u16                     af;

        u16                     tun_type;       /* tunnel type */
        __be16                  tun_port;       /* tunnel port */
        u16                     tun_flags;      /* tunnel flags */
};


/*
 * The information about the virtual service offered to the net and the
 * forwarding entries.
 */
struct ip_vs_service {
        struct hlist_node       s_list;   /* for normal service table */
        struct hlist_node       f_list;   /* for fwmark-based service table */
        atomic_t                refcnt;   /* reference counter */

        u16                     af;       /* address family */
        __u16                   protocol; /* which protocol (TCP/UDP) */
        union nf_inet_addr      addr;     /* IP address for virtual service */
        __be16                  port;     /* port number for the service */
        __u32                   fwmark;   /* firewall mark of the service */
        unsigned int            flags;    /* service status flags */
        unsigned int            timeout;  /* persistent timeout in ticks */
        __be32                  netmask;  /* grouping granularity, mask/plen */
        struct netns_ipvs       *ipvs;

        struct list_head        destinations;  /* real server d-linked list */
        __u32                   num_dests;     /* number of servers */
        struct ip_vs_stats      stats;         /* statistics for the service */

        /* for scheduling */
        struct ip_vs_scheduler __rcu *scheduler; /* bound scheduler object */
        spinlock_t              sched_lock;    /* lock sched_data */
        void                    *sched_data;   /* scheduler application data */

        /* alternate persistence engine */
        struct ip_vs_pe __rcu   *pe;
        int                     conntrack_afmask;

        struct rcu_head         rcu_head;
};

/* Information for cached dst */
struct ip_vs_dest_dst {
        struct dst_entry        *dst_cache;     /* destination cache entry */
        u32                     dst_cookie;
        union nf_inet_addr      dst_saddr;
        struct rcu_head         rcu_head;
};

/* The real server destination forwarding entry with ip address, port number,
 * and so on.
 */
struct ip_vs_dest {
        struct list_head        n_list;   /* for the dests in the service */
        struct hlist_node       d_list;   /* for table with all the dests */

        u16                     af;             /* address family */
        __be16                  port;           /* port number of the server */
        union nf_inet_addr      addr;           /* IP address of the server */
        volatile unsigned int   flags;          /* dest status flags */
        atomic_t                conn_flags;     /* flags to copy to conn */
        atomic_t                weight;         /* server weight */
        atomic_t                last_weight;    /* server latest weight */
        __u16                   tun_type;       /* tunnel type */
        __be16                  tun_port;       /* tunnel port */
        __u16                   tun_flags;      /* tunnel flags */

        refcount_t              refcnt;         /* reference counter */
        struct ip_vs_stats      stats;          /* statistics */
        unsigned long           idle_start;     /* start time, jiffies */

        /* connection counters and thresholds */
        atomic_t                activeconns;    /* active connections */
        atomic_t                inactconns;     /* inactive connections */
        atomic_t                persistconns;   /* persistent connections */
        __u32                   u_threshold;    /* upper threshold */
        __u32                   l_threshold;    /* lower threshold */

        /* for destination cache */
        spinlock_t              dst_lock;       /* lock of dst_cache */
        struct ip_vs_dest_dst __rcu *dest_dst;  /* cached dst info */

        /* for virtual service */
        struct ip_vs_service __rcu *svc;        /* service it belongs to */
        __u16                   protocol;       /* which protocol (TCP/UDP) */
        __be16                  vport;          /* virtual port number */
        union nf_inet_addr      vaddr;          /* virtual IP address */
        __u32                   vfwmark;        /* firewall mark of service */

        struct rcu_head         rcu_head;
        struct list_head        t_list;         /* in dest_trash */
        unsigned int            in_rs_table:1;  /* we are in rs_table */
};

/* The scheduler object */
struct ip_vs_scheduler {
        struct list_head        n_list;         /* d-linked list head */
        char                    *name;          /* scheduler name */
        atomic_t                refcnt;         /* reference counter */
        struct module           *module;        /* THIS_MODULE/NULL */

        /* scheduler initializing service */
        int (*init_service)(struct ip_vs_service *svc);
        /* scheduling service finish */
        void (*done_service)(struct ip_vs_service *svc);
        /* dest is linked */
        int (*add_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);
        /* dest is unlinked */
        int (*del_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);
        /* dest is updated */
        int (*upd_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);

        /* selecting a server from the given service */
        struct ip_vs_dest* (*schedule)(struct ip_vs_service *svc,
                                       const struct sk_buff *skb,
                                       struct ip_vs_iphdr *iph);
};

/* The persistence engine object */
struct ip_vs_pe {
        struct list_head        n_list;         /* d-linked list head */
        char                    *name;          /* scheduler name */
        atomic_t                refcnt;         /* reference counter */
        struct module           *module;        /* THIS_MODULE/NULL */

        /* get the connection template, if any */
        int (*fill_param)(struct ip_vs_conn_param *p, struct sk_buff *skb);
        bool (*ct_match)(const struct ip_vs_conn_param *p,
                         struct ip_vs_conn *ct);
        u32 (*hashkey_raw)(const struct ip_vs_conn_param *p, u32 initval,
                           bool inverse);
        int (*show_pe_data)(const struct ip_vs_conn *cp, char *buf);
        /* create connections for real-server outgoing packets */
        struct ip_vs_conn* (*conn_out)(struct ip_vs_service *svc,
                                       struct ip_vs_dest *dest,
                                       struct sk_buff *skb,
                                       const struct ip_vs_iphdr *iph,
                                       __be16 dport, __be16 cport);
};

/* The application module object (a.k.a. app incarnation) */
struct ip_vs_app {
        struct list_head        a_list;         /* member in app list */
        int                     type;           /* IP_VS_APP_TYPE_xxx */
        char                    *name;          /* application module name */
        __u16                   protocol;
        struct module           *module;        /* THIS_MODULE/NULL */
        struct list_head        incs_list;      /* list of incarnations */

        /* members for application incarnations */
        struct list_head        p_list;         /* member in proto app list */
        struct ip_vs_app        *app;           /* its real application */
        __be16                  port;           /* port number in net order */
        atomic_t                usecnt;         /* usage counter */
        struct rcu_head         rcu_head;

        /* output hook: Process packet in inout direction, diff set for TCP.
         * Return: 0=Error, 1=Payload Not Mangled/Mangled but checksum is ok,
         *         2=Mangled but checksum was not updated
         */
        int (*pkt_out)(struct ip_vs_app *, struct ip_vs_conn *,
                       struct sk_buff *, int *diff, struct ip_vs_iphdr *ipvsh);

        /* input hook: Process packet in outin direction, diff set for TCP.
         * Return: 0=Error, 1=Payload Not Mangled/Mangled but checksum is ok,
         *         2=Mangled but checksum was not updated
         */
        int (*pkt_in)(struct ip_vs_app *, struct ip_vs_conn *,
                      struct sk_buff *, int *diff, struct ip_vs_iphdr *ipvsh);

        /* ip_vs_app initializer */
        int (*init_conn)(struct ip_vs_app *, struct ip_vs_conn *);

        /* ip_vs_app finish */
        int (*done_conn)(struct ip_vs_app *, struct ip_vs_conn *);


        /* not used now */
        int (*bind_conn)(struct ip_vs_app *, struct ip_vs_conn *,
                         struct ip_vs_protocol *);

        void (*unbind_conn)(struct ip_vs_app *, struct ip_vs_conn *);

        int *                   timeout_table;
        int *                   timeouts;
        int                     timeouts_size;

        int (*conn_schedule)(struct sk_buff *skb, struct ip_vs_app *app,
                             int *verdict, struct ip_vs_conn **cpp);

        struct ip_vs_conn *
        (*conn_in_get)(const struct sk_buff *skb, struct ip_vs_app *app,
                       const struct iphdr *iph, int inverse);

        struct ip_vs_conn *
        (*conn_out_get)(const struct sk_buff *skb, struct ip_vs_app *app,
                        const struct iphdr *iph, int inverse);

        int (*state_transition)(struct ip_vs_conn *cp, int direction,
                                const struct sk_buff *skb,
                                struct ip_vs_app *app);

        void (*timeout_change)(struct ip_vs_app *app, int flags);
};

struct ipvs_master_sync_state {
        struct list_head        sync_queue;
        struct ip_vs_sync_buff  *sync_buff;
        unsigned long           sync_queue_len;
        unsigned int            sync_queue_delay;
        struct delayed_work     master_wakeup_work;
        struct netns_ipvs       *ipvs;
};

struct ip_vs_sync_thread_data;

/* How much time to keep dests in trash */
#define IP_VS_DEST_TRASH_PERIOD         (120 * HZ)

struct ipvs_sync_daemon_cfg {
        union nf_inet_addr      mcast_group;
        int                     syncid;
        u16                     sync_maxlen;
        u16                     mcast_port;
        u8                      mcast_af;
        u8                      mcast_ttl;
        /* multicast interface name */
        char                    mcast_ifn[IP_VS_IFNAME_MAXLEN];
};

/* IPVS in network namespace */
struct netns_ipvs {
        int                     gen;            /* Generation */
        int                     enable;         /* enable like nf_hooks do */
        /* Hash table: for real service lookups */
        #define IP_VS_RTAB_BITS 4
        #define IP_VS_RTAB_SIZE (1 << IP_VS_RTAB_BITS)
        #define IP_VS_RTAB_MASK (IP_VS_RTAB_SIZE - 1)

        struct hlist_head       rs_table[IP_VS_RTAB_SIZE];
        /* ip_vs_app */
        struct list_head        app_list;
        /* ip_vs_proto */
        #define IP_VS_PROTO_TAB_SIZE    32      /* must be power of 2 */
        struct ip_vs_proto_data *proto_data_table[IP_VS_PROTO_TAB_SIZE];
        /* ip_vs_proto_tcp */
#ifdef CONFIG_IP_VS_PROTO_TCP
        #define TCP_APP_TAB_BITS        4
        #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
        #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
        struct list_head        tcp_apps[TCP_APP_TAB_SIZE];
#endif
        /* ip_vs_proto_udp */
#ifdef CONFIG_IP_VS_PROTO_UDP
        #define UDP_APP_TAB_BITS        4
        #define UDP_APP_TAB_SIZE        (1 << UDP_APP_TAB_BITS)
        #define UDP_APP_TAB_MASK        (UDP_APP_TAB_SIZE - 1)
        struct list_head        udp_apps[UDP_APP_TAB_SIZE];
#endif
        /* ip_vs_proto_sctp */
#ifdef CONFIG_IP_VS_PROTO_SCTP
        #define SCTP_APP_TAB_BITS       4
        #define SCTP_APP_TAB_SIZE       (1 << SCTP_APP_TAB_BITS)
        #define SCTP_APP_TAB_MASK       (SCTP_APP_TAB_SIZE - 1)
        /* Hash table for SCTP application incarnations  */
        struct list_head        sctp_apps[SCTP_APP_TAB_SIZE];
#endif
        /* ip_vs_conn */
        atomic_t                conn_count;      /* connection counter */

        /* ip_vs_ctl */
        struct ip_vs_stats_rcu  *tot_stats;      /* Statistics & est. */

        int                     num_services;    /* no of virtual services */
        int                     num_services6;   /* IPv6 virtual services */

        /* Trash for destinations */
        struct list_head        dest_trash;
        spinlock_t              dest_trash_lock;
        struct timer_list       dest_trash_timer; /* expiration timer */
        /* Service counters */
        atomic_t                ftpsvc_counter;
        atomic_t                nullsvc_counter;
        atomic_t                conn_out_counter;

#ifdef CONFIG_SYSCTL
        /* delayed work for expiring no dest connections */
        struct delayed_work     expire_nodest_conn_work;
        /* 1/rate drop and drop-entry variables */
        struct delayed_work     defense_work;   /* Work handler */
        int                     drop_rate;
        int                     drop_counter;
        int                     old_secure_tcp;
        atomic_t                dropentry;
        /* locks in ctl.c */
        spinlock_t              dropentry_lock;  /* drop entry handling */
        spinlock_t              droppacket_lock; /* drop packet handling */
        spinlock_t              securetcp_lock;  /* state and timeout tables */

        /* sys-ctl struct */
        struct ctl_table_header *sysctl_hdr;
        struct ctl_table        *sysctl_tbl;
#endif

        /* sysctl variables */
        int                     sysctl_amemthresh;
        int                     sysctl_am_droprate;
        int                     sysctl_drop_entry;
        int                     sysctl_drop_packet;
        int                     sysctl_secure_tcp;
#ifdef CONFIG_IP_VS_NFCT
        int                     sysctl_conntrack;
#endif
        int                     sysctl_snat_reroute;
        int                     sysctl_sync_ver;
        int                     sysctl_sync_ports;
        int                     sysctl_sync_persist_mode;
        unsigned long           sysctl_sync_qlen_max;
        int                     sysctl_sync_sock_size;
        int                     sysctl_cache_bypass;
        int                     sysctl_expire_nodest_conn;
        int                     sysctl_sloppy_tcp;
        int                     sysctl_sloppy_sctp;
        int                     sysctl_expire_quiescent_template;
        int                     sysctl_sync_threshold[2];
        unsigned int            sysctl_sync_refresh_period;
        int                     sysctl_sync_retries;
        int                     sysctl_nat_icmp_send;
        int                     sysctl_pmtu_disc;
        int                     sysctl_backup_only;
        int                     sysctl_conn_reuse_mode;
        int                     sysctl_schedule_icmp;
        int                     sysctl_ignore_tunneled;
        int                     sysctl_run_estimation;
#ifdef CONFIG_SYSCTL
        cpumask_var_t           sysctl_est_cpulist;     /* kthread cpumask */
        int                     est_cpulist_valid;      /* cpulist set */
        int                     sysctl_est_nice;        /* kthread nice */
        int                     est_stopped;            /* stop tasks */
#endif

        /* ip_vs_lblc */
        int                     sysctl_lblc_expiration;
        struct ctl_table_header *lblc_ctl_header;
        struct ctl_table        *lblc_ctl_table;
        /* ip_vs_lblcr */
        int                     sysctl_lblcr_expiration;
        struct ctl_table_header *lblcr_ctl_header;
        struct ctl_table        *lblcr_ctl_table;
        /* ip_vs_est */
        struct delayed_work     est_reload_work;/* Reload kthread tasks */
        struct mutex            est_mutex;      /* protect kthread tasks */
        struct hlist_head       est_temp_list;  /* Ests during calc phase */
        struct ip_vs_est_kt_data **est_kt_arr;  /* Array of kthread data ptrs */
        unsigned long           est_max_threads;/* Hard limit of kthreads */
        int                     est_calc_phase; /* Calculation phase */
        int                     est_chain_max;  /* Calculated chain_max */
        int                     est_kt_count;   /* Allocated ptrs */
        int                     est_add_ktid;   /* ktid where to add ests */
        atomic_t                est_genid;      /* kthreads reload genid */
        atomic_t                est_genid_done; /* applied genid */
        /* ip_vs_sync */
        spinlock_t              sync_lock;
        struct ipvs_master_sync_state *ms;
        spinlock_t              sync_buff_lock;
        struct ip_vs_sync_thread_data *master_tinfo;
        struct ip_vs_sync_thread_data *backup_tinfo;
        int                     threads_mask;
        volatile int            sync_state;
        struct mutex            sync_mutex;
        struct ipvs_sync_daemon_cfg     mcfg;   /* Master Configuration */
        struct ipvs_sync_daemon_cfg     bcfg;   /* Backup Configuration */
        /* net name space ptr */
        struct net              *net;            /* Needed by timer routines */
        /* Number of heterogeneous destinations, needed because heterogeneous
         * are not supported when synchronization is enabled.
         */
        unsigned int            mixed_address_family_dests;
        unsigned int            hooks_afmask;   /* &1=AF_INET, &2=AF_INET6 */
};

#define DEFAULT_SYNC_THRESHOLD  3
#define DEFAULT_SYNC_PERIOD     50
#define DEFAULT_SYNC_VER        1
#define DEFAULT_SLOPPY_TCP      0
#define DEFAULT_SLOPPY_SCTP     0
#define DEFAULT_SYNC_REFRESH_PERIOD     (0U * HZ)
#define DEFAULT_SYNC_RETRIES            0
#define IPVS_SYNC_WAKEUP_RATE   8
#define IPVS_SYNC_QLEN_MAX      (IPVS_SYNC_WAKEUP_RATE * 4)
#define IPVS_SYNC_SEND_DELAY    (HZ / 50)
#define IPVS_SYNC_CHECK_PERIOD  HZ
#define IPVS_SYNC_FLUSH_TIME    (HZ * 2)
#define IPVS_SYNC_PORTS_MAX     (1 << 6)

#ifdef CONFIG_SYSCTL

static inline int sysctl_sync_threshold(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_threshold[0];
}

static inline int sysctl_sync_period(struct netns_ipvs *ipvs)
{
        return READ_ONCE(ipvs->sysctl_sync_threshold[1]);
}

static inline unsigned int sysctl_sync_refresh_period(struct netns_ipvs *ipvs)
{
        return READ_ONCE(ipvs->sysctl_sync_refresh_period);
}

static inline int sysctl_sync_retries(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_retries;
}

static inline int sysctl_sync_ver(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_ver;
}

static inline int sysctl_sloppy_tcp(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sloppy_tcp;
}

static inline int sysctl_sloppy_sctp(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sloppy_sctp;
}

static inline int sysctl_sync_ports(struct netns_ipvs *ipvs)
{
        return READ_ONCE(ipvs->sysctl_sync_ports);
}

static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_persist_mode;
}

static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_qlen_max;
}

static inline int sysctl_sync_sock_size(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_sync_sock_size;
}

static inline int sysctl_pmtu_disc(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_pmtu_disc;
}

static inline int sysctl_backup_only(struct netns_ipvs *ipvs)
{
        return ipvs->sync_state & IP_VS_STATE_BACKUP &&
               ipvs->sysctl_backup_only;
}

static inline int sysctl_conn_reuse_mode(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_conn_reuse_mode;
}

static inline int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_expire_nodest_conn;
}

static inline int sysctl_schedule_icmp(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_schedule_icmp;
}

static inline int sysctl_ignore_tunneled(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_ignore_tunneled;
}

static inline int sysctl_cache_bypass(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_cache_bypass;
}

static inline int sysctl_run_estimation(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_run_estimation;
}

static inline const struct cpumask *sysctl_est_cpulist(struct netns_ipvs *ipvs)
{
        if (ipvs->est_cpulist_valid)
                return ipvs->sysctl_est_cpulist;
        else
                return housekeeping_cpumask(HK_TYPE_KTHREAD);
}

static inline const struct cpumask *sysctl_est_preferred_cpulist(struct netns_ipvs *ipvs)
{
        if (ipvs->est_cpulist_valid)
                return ipvs->sysctl_est_cpulist;
        else
                return NULL;
}

static inline int sysctl_est_nice(struct netns_ipvs *ipvs)
{
        return ipvs->sysctl_est_nice;
}

#else

static inline int sysctl_sync_threshold(struct netns_ipvs *ipvs)
{
        return DEFAULT_SYNC_THRESHOLD;
}

static inline int sysctl_sync_period(struct netns_ipvs *ipvs)
{
        return DEFAULT_SYNC_PERIOD;
}

static inline unsigned int sysctl_sync_refresh_period(struct netns_ipvs *ipvs)
{
        return DEFAULT_SYNC_REFRESH_PERIOD;
}

static inline int sysctl_sync_retries(struct netns_ipvs *ipvs)
{
        return DEFAULT_SYNC_RETRIES & 3;
}

static inline int sysctl_sync_ver(struct netns_ipvs *ipvs)
{
        return DEFAULT_SYNC_VER;
}

static inline int sysctl_sloppy_tcp(struct netns_ipvs *ipvs)
{
        return DEFAULT_SLOPPY_TCP;
}

static inline int sysctl_sloppy_sctp(struct netns_ipvs *ipvs)
{
        return DEFAULT_SLOPPY_SCTP;
}

static inline int sysctl_sync_ports(struct netns_ipvs *ipvs)
{
        return 1;
}

static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
{
        return IPVS_SYNC_QLEN_MAX;
}

static inline int sysctl_sync_sock_size(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_pmtu_disc(struct netns_ipvs *ipvs)
{
        return 1;
}

static inline int sysctl_backup_only(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_conn_reuse_mode(struct netns_ipvs *ipvs)
{
        return 1;
}

static inline int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_schedule_icmp(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_ignore_tunneled(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_cache_bypass(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline int sysctl_run_estimation(struct netns_ipvs *ipvs)
{
        return 1;
}

static inline const struct cpumask *sysctl_est_cpulist(struct netns_ipvs *ipvs)
{
        return housekeeping_cpumask(HK_TYPE_KTHREAD);
}

static inline const struct cpumask *sysctl_est_preferred_cpulist(struct netns_ipvs *ipvs)
{
        return NULL;
}

static inline int sysctl_est_nice(struct netns_ipvs *ipvs)
{
        return IPVS_EST_NICE;
}

#endif

/* IPVS core functions
 * (from ip_vs_core.c)
 */
const char *ip_vs_proto_name(unsigned int proto);
void ip_vs_init_hash_table(struct list_head *table, int rows);
struct ip_vs_conn *ip_vs_new_conn_out(struct ip_vs_service *svc,
                                      struct ip_vs_dest *dest,
                                      struct sk_buff *skb,
                                      const struct ip_vs_iphdr *iph,
                                      __be16 dport,
                                      __be16 cport);
#define IP_VS_INIT_HASH_TABLE(t) ip_vs_init_hash_table((t), ARRAY_SIZE((t)))

#define IP_VS_APP_TYPE_FTP      1

/* ip_vs_conn handling functions
 * (from ip_vs_conn.c)
 */
enum {
        IP_VS_DIR_INPUT = 0,
        IP_VS_DIR_OUTPUT,
        IP_VS_DIR_INPUT_ONLY,
        IP_VS_DIR_LAST,
};

static inline void ip_vs_conn_fill_param(struct netns_ipvs *ipvs, int af, int protocol,
                                         const union nf_inet_addr *caddr,
                                         __be16 cport,
                                         const union nf_inet_addr *vaddr,
                                         __be16 vport,
                                         struct ip_vs_conn_param *p)
{
        p->ipvs = ipvs;
        p->af = af;
        p->protocol = protocol;
        p->caddr = caddr;
        p->cport = cport;
        p->vaddr = vaddr;
        p->vport = vport;
        p->pe = NULL;
        p->pe_data = NULL;
}

struct ip_vs_conn *ip_vs_conn_in_get(const struct ip_vs_conn_param *p);
struct ip_vs_conn *ip_vs_ct_in_get(const struct ip_vs_conn_param *p);

struct ip_vs_conn * ip_vs_conn_in_get_proto(struct netns_ipvs *ipvs, int af,
                                            const struct sk_buff *skb,
                                            const struct ip_vs_iphdr *iph);

struct ip_vs_conn *ip_vs_conn_out_get(const struct ip_vs_conn_param *p);

struct ip_vs_conn * ip_vs_conn_out_get_proto(struct netns_ipvs *ipvs, int af,
                                             const struct sk_buff *skb,
                                             const struct ip_vs_iphdr *iph);

/* Get reference to gain full access to conn.
 * By default, RCU read-side critical sections have access only to
 * conn fields and its PE data, see ip_vs_conn_rcu_free() for reference.
 */
static inline bool __ip_vs_conn_get(struct ip_vs_conn *cp)
{
        return refcount_inc_not_zero(&cp->refcnt);
}

/* put back the conn without restarting its timer */
static inline void __ip_vs_conn_put(struct ip_vs_conn *cp)
{
        smp_mb__before_atomic();
        refcount_dec(&cp->refcnt);
}
void ip_vs_conn_put(struct ip_vs_conn *cp);
void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport);

struct ip_vs_conn *ip_vs_conn_new(const struct ip_vs_conn_param *p, int dest_af,
                                  const union nf_inet_addr *daddr,
                                  __be16 dport, unsigned int flags,
                                  struct ip_vs_dest *dest, __u32 fwmark);
void ip_vs_conn_expire_now(struct ip_vs_conn *cp);

const char *ip_vs_state_name(const struct ip_vs_conn *cp);

void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp);
int ip_vs_check_template(struct ip_vs_conn *ct, struct ip_vs_dest *cdest);
void ip_vs_random_dropentry(struct netns_ipvs *ipvs);
int ip_vs_conn_init(void);
void ip_vs_conn_cleanup(void);

static inline void ip_vs_control_del(struct ip_vs_conn *cp)
{
        struct ip_vs_conn *ctl_cp = cp->control;
        if (!ctl_cp) {
                IP_VS_ERR_BUF("request control DEL for uncontrolled: "
                              "%s:%d to %s:%d\n",
                              IP_VS_DBG_ADDR(cp->af, &cp->caddr),
                              ntohs(cp->cport),
                              IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
                              ntohs(cp->vport));

                return;
        }

        IP_VS_DBG_BUF(7, "DELeting control for: "
                      "cp.dst=%s:%d ctl_cp.dst=%s:%d\n",
                      IP_VS_DBG_ADDR(cp->af, &cp->caddr),
                      ntohs(cp->cport),
                      IP_VS_DBG_ADDR(cp->af, &ctl_cp->caddr),
                      ntohs(ctl_cp->cport));

        cp->control = NULL;
        if (atomic_read(&ctl_cp->n_control) == 0) {
                IP_VS_ERR_BUF("BUG control DEL with n=0 : "
                              "%s:%d to %s:%d\n",
                              IP_VS_DBG_ADDR(cp->af, &cp->caddr),
                              ntohs(cp->cport),
                              IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
                              ntohs(cp->vport));

                return;
        }
        atomic_dec(&ctl_cp->n_control);
}

static inline void
ip_vs_control_add(struct ip_vs_conn *cp, struct ip_vs_conn *ctl_cp)
{
        if (cp->control) {
                IP_VS_ERR_BUF("request control ADD for already controlled: "
                              "%s:%d to %s:%d\n",
                              IP_VS_DBG_ADDR(cp->af, &cp->caddr),
                              ntohs(cp->cport),
                              IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
                              ntohs(cp->vport));

                ip_vs_control_del(cp);
        }

        IP_VS_DBG_BUF(7, "ADDing control for: "
                      "cp.dst=%s:%d ctl_cp.dst=%s:%d\n",
                      IP_VS_DBG_ADDR(cp->af, &cp->caddr),
                      ntohs(cp->cport),
                      IP_VS_DBG_ADDR(cp->af, &ctl_cp->caddr),
                      ntohs(ctl_cp->cport));

        cp->control = ctl_cp;
        atomic_inc(&ctl_cp->n_control);
}

/* Mark our template as assured */
static inline void
ip_vs_control_assure_ct(struct ip_vs_conn *cp)
{
        struct ip_vs_conn *ct = cp->control;

        if (ct && !(ct->state & IP_VS_CTPL_S_ASSURED) &&
            (ct->flags & IP_VS_CONN_F_TEMPLATE))
                ct->state |= IP_VS_CTPL_S_ASSURED;
}

/* IPVS netns init & cleanup functions */
int ip_vs_estimator_net_init(struct netns_ipvs *ipvs);
int ip_vs_control_net_init(struct netns_ipvs *ipvs);
int ip_vs_protocol_net_init(struct netns_ipvs *ipvs);
int ip_vs_app_net_init(struct netns_ipvs *ipvs);
int ip_vs_conn_net_init(struct netns_ipvs *ipvs);
int ip_vs_sync_net_init(struct netns_ipvs *ipvs);
void ip_vs_conn_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_app_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_protocol_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_control_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_estimator_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_sync_net_cleanup(struct netns_ipvs *ipvs);
void ip_vs_service_nets_cleanup(struct list_head *net_list);

/* IPVS application functions
 * (from ip_vs_app.c)
 */
#define IP_VS_APP_MAX_PORTS  8
struct ip_vs_app *register_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app);
void unregister_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app);
int ip_vs_bind_app(struct ip_vs_conn *cp, struct ip_vs_protocol *pp);
void ip_vs_unbind_app(struct ip_vs_conn *cp);
int register_ip_vs_app_inc(struct netns_ipvs *ipvs, struct ip_vs_app *app, __u16 proto,
                           __u16 port);
int ip_vs_app_inc_get(struct ip_vs_app *inc);
void ip_vs_app_inc_put(struct ip_vs_app *inc);

int ip_vs_app_pkt_out(struct ip_vs_conn *, struct sk_buff *skb,
                      struct ip_vs_iphdr *ipvsh);
int ip_vs_app_pkt_in(struct ip_vs_conn *, struct sk_buff *skb,
                     struct ip_vs_iphdr *ipvsh);

int register_ip_vs_pe(struct ip_vs_pe *pe);
int unregister_ip_vs_pe(struct ip_vs_pe *pe);
struct ip_vs_pe *ip_vs_pe_getbyname(const char *name);
struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name);

/* Use a #define to avoid all of module.h just for these trivial ops */
#define ip_vs_pe_get(pe)                        \
        if (pe && pe->module)                   \
                __module_get(pe->module);

#define ip_vs_pe_put(pe)                        \
        if (pe && pe->module)                   \
                module_put(pe->module);

/* IPVS protocol functions (from ip_vs_proto.c) */
int ip_vs_protocol_init(void);
void ip_vs_protocol_cleanup(void);
void ip_vs_protocol_timeout_change(struct netns_ipvs *ipvs, int flags);
int *ip_vs_create_timeout_table(int *table, int size);
void ip_vs_tcpudp_debug_packet(int af, struct ip_vs_protocol *pp,
                               const struct sk_buff *skb, int offset,
                               const char *msg);

extern struct ip_vs_protocol ip_vs_protocol_tcp;
extern struct ip_vs_protocol ip_vs_protocol_udp;
extern struct ip_vs_protocol ip_vs_protocol_icmp;
extern struct ip_vs_protocol ip_vs_protocol_esp;
extern struct ip_vs_protocol ip_vs_protocol_ah;
extern struct ip_vs_protocol ip_vs_protocol_sctp;

/* Registering/unregistering scheduler functions
 * (from ip_vs_sched.c)
 */
int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler);
int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler);
int ip_vs_bind_scheduler(struct ip_vs_service *svc,
                         struct ip_vs_scheduler *scheduler);
void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
                            struct ip_vs_scheduler *sched);
struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name);
void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler);
struct ip_vs_conn *
ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
               struct ip_vs_proto_data *pd, int *ignored,
               struct ip_vs_iphdr *iph);
int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
                struct ip_vs_proto_data *pd, struct ip_vs_iphdr *iph);

void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg);

/* IPVS control data and functions (from ip_vs_ctl.c) */
extern struct ip_vs_stats ip_vs_stats;
extern int sysctl_ip_vs_sync_ver;

struct ip_vs_service *
ip_vs_service_find(struct netns_ipvs *ipvs, int af, __u32 fwmark, __u16 protocol,
                  const union nf_inet_addr *vaddr, __be16 vport);

bool ip_vs_has_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol,
                            const union nf_inet_addr *daddr, __be16 dport);

struct ip_vs_dest *
ip_vs_find_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol,
                        const union nf_inet_addr *daddr, __be16 dport);
struct ip_vs_dest *ip_vs_find_tunnel(struct netns_ipvs *ipvs, int af,
                                     const union nf_inet_addr *daddr,
                                     __be16 tun_port);

int ip_vs_use_count_inc(void);
void ip_vs_use_count_dec(void);
int ip_vs_register_nl_ioctl(void);
void ip_vs_unregister_nl_ioctl(void);
int ip_vs_control_init(void);
void ip_vs_control_cleanup(void);
struct ip_vs_dest *
ip_vs_find_dest(struct netns_ipvs *ipvs, int svc_af, int dest_af,
                const union nf_inet_addr *daddr, __be16 dport,
                const union nf_inet_addr *vaddr, __be16 vport,
                __u16 protocol, __u32 fwmark, __u32 flags);
void ip_vs_try_bind_dest(struct ip_vs_conn *cp);

static inline void ip_vs_dest_hold(struct ip_vs_dest *dest)
{
        refcount_inc(&dest->refcnt);
}

static inline void ip_vs_dest_put(struct ip_vs_dest *dest)
{
        smp_mb__before_atomic();
        refcount_dec(&dest->refcnt);
}

static inline void ip_vs_dest_put_and_free(struct ip_vs_dest *dest)
{
        if (refcount_dec_and_test(&dest->refcnt))
                kfree(dest);
}

/* IPVS sync daemon data and function prototypes
 * (from ip_vs_sync.c)
 */
int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *cfg,
                      int state);
int stop_sync_thread(struct netns_ipvs *ipvs, int state);
void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts);

/* IPVS rate estimator prototypes (from ip_vs_est.c) */
int ip_vs_start_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats);
void ip_vs_stop_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats);
void ip_vs_zero_estimator(struct ip_vs_stats *stats);
void ip_vs_read_estimator(struct ip_vs_kstats *dst, struct ip_vs_stats *stats);
void ip_vs_est_reload_start(struct netns_ipvs *ipvs);
int ip_vs_est_kthread_start(struct netns_ipvs *ipvs,
                            struct ip_vs_est_kt_data *kd);
void ip_vs_est_kthread_stop(struct ip_vs_est_kt_data *kd);

static inline void ip_vs_est_stopped_recalc(struct netns_ipvs *ipvs)
{
#ifdef CONFIG_SYSCTL
        /* Stop tasks while cpulist is empty or if disabled with flag */
        ipvs->est_stopped = !sysctl_run_estimation(ipvs) ||
                            (ipvs->est_cpulist_valid &&
                             cpumask_empty(sysctl_est_cpulist(ipvs)));
#endif
}

static inline bool ip_vs_est_stopped(struct netns_ipvs *ipvs)
{
#ifdef CONFIG_SYSCTL
        return ipvs->est_stopped;
#else
        return false;
#endif
}

static inline int ip_vs_est_max_threads(struct netns_ipvs *ipvs)
{
        unsigned int limit = IPVS_EST_CPU_KTHREADS *
                             cpumask_weight(sysctl_est_cpulist(ipvs));

        return max(1U, limit);
}

/* Various IPVS packet transmitters (from ip_vs_xmit.c) */
int ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                    struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                  struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                    struct ip_vs_protocol *pp, int offset,
                    unsigned int hooknum, struct ip_vs_iphdr *iph);
void ip_vs_dest_dst_rcu_free(struct rcu_head *head);

#ifdef CONFIG_IP_VS_IPV6
int ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
                         struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
                         struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
                     struct ip_vs_protocol *pp, struct ip_vs_iphdr *iph);
int ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
                       struct ip_vs_protocol *pp, int offset,
                       unsigned int hooknum, struct ip_vs_iphdr *iph);
#endif

#ifdef CONFIG_SYSCTL
/* This is a simple mechanism to ignore packets when
 * we are loaded. Just set ip_vs_drop_rate to 'n' and
 * we start to drop 1/rate of the packets
 */
static inline int ip_vs_todrop(struct netns_ipvs *ipvs)
{
        if (!ipvs->drop_rate)
                return 0;
        if (--ipvs->drop_counter > 0)
                return 0;
        ipvs->drop_counter = ipvs->drop_rate;
        return 1;
}
#else
static inline int ip_vs_todrop(struct netns_ipvs *ipvs) { return 0; }
#endif

#ifdef CONFIG_SYSCTL
/* Enqueue delayed work for expiring no dest connections
 * Only run when sysctl_expire_nodest=1
 */
static inline void ip_vs_enqueue_expire_nodest_conns(struct netns_ipvs *ipvs)
{
        if (sysctl_expire_nodest_conn(ipvs))
                queue_delayed_work(system_long_wq,
                                   &ipvs->expire_nodest_conn_work, 1);
}

void ip_vs_expire_nodest_conn_flush(struct netns_ipvs *ipvs);
#else
static inline void ip_vs_enqueue_expire_nodest_conns(struct netns_ipvs *ipvs) {}
#endif

#define IP_VS_DFWD_METHOD(dest) (atomic_read(&(dest)->conn_flags) & \
                                 IP_VS_CONN_F_FWD_MASK)

/* ip_vs_fwd_tag returns the forwarding tag of the connection */
#define IP_VS_FWD_METHOD(cp)  (cp->flags & IP_VS_CONN_F_FWD_MASK)

static inline char ip_vs_fwd_tag(struct ip_vs_conn *cp)
{
        char fwd;

        switch (IP_VS_FWD_METHOD(cp)) {
        case IP_VS_CONN_F_MASQ:
                fwd = 'M'; break;
        case IP_VS_CONN_F_LOCALNODE:
                fwd = 'L'; break;
        case IP_VS_CONN_F_TUNNEL:
                fwd = 'T'; break;
        case IP_VS_CONN_F_DROUTE:
                fwd = 'R'; break;
        case IP_VS_CONN_F_BYPASS:
                fwd = 'B'; break;
        default:
                fwd = '?'; break;
        }
        return fwd;
}

void ip_vs_nat_icmp(struct sk_buff *skb, struct ip_vs_protocol *pp,
                    struct ip_vs_conn *cp, int dir);

#ifdef CONFIG_IP_VS_IPV6
void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct ip_vs_protocol *pp,
                       struct ip_vs_conn *cp, int dir);
#endif

__sum16 ip_vs_checksum_complete(struct sk_buff *skb, int offset);

static inline __wsum ip_vs_check_diff4(__be32 old, __be32 new, __wsum oldsum)
{
        __be32 diff[2] = { ~old, new };

        return csum_partial(diff, sizeof(diff), oldsum);
}

#ifdef CONFIG_IP_VS_IPV6
static inline __wsum ip_vs_check_diff16(const __be32 *old, const __be32 *new,
                                        __wsum oldsum)
{
        __be32 diff[8] = { ~old[3], ~old[2], ~old[1], ~old[0],
                            new[3],  new[2],  new[1],  new[0] };

        return csum_partial(diff, sizeof(diff), oldsum);
}
#endif

static inline __wsum ip_vs_check_diff2(__be16 old, __be16 new, __wsum oldsum)
{
        __be16 diff[2] = { ~old, new };

        return csum_partial(diff, sizeof(diff), oldsum);
}

/* Forget current conntrack (unconfirmed) and attach notrack entry */
static inline void ip_vs_notrack(struct sk_buff *skb)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
        enum ip_conntrack_info ctinfo;
        struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

        if (ct) {
                nf_conntrack_put(&ct->ct_general);
                nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
        }
#endif
}

#ifdef CONFIG_IP_VS_NFCT
/* Netfilter connection tracking
 * (from ip_vs_nfct.c)
 */
static inline int ip_vs_conntrack_enabled(struct netns_ipvs *ipvs)
{
#ifdef CONFIG_SYSCTL
        return ipvs->sysctl_conntrack;
#else
        return 0;
#endif
}

void ip_vs_update_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp,
                            int outin);
int ip_vs_confirm_conntrack(struct sk_buff *skb);
void ip_vs_nfct_expect_related(struct sk_buff *skb, struct nf_conn *ct,
                               struct ip_vs_conn *cp, u_int8_t proto,
                               const __be16 port, int from_rs);
void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp);

#else

static inline int ip_vs_conntrack_enabled(struct netns_ipvs *ipvs)
{
        return 0;
}

static inline void ip_vs_update_conntrack(struct sk_buff *skb,
                                          struct ip_vs_conn *cp, int outin)
{
}

static inline int ip_vs_confirm_conntrack(struct sk_buff *skb)
{
        return NF_ACCEPT;
}

static inline void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp)
{
}
#endif /* CONFIG_IP_VS_NFCT */

/* Using old conntrack that can not be redirected to another real server? */
static inline bool ip_vs_conn_uses_old_conntrack(struct ip_vs_conn *cp,
                                                 struct sk_buff *skb)
{
#ifdef CONFIG_IP_VS_NFCT
        enum ip_conntrack_info ctinfo;
        struct nf_conn *ct;

        ct = nf_ct_get(skb, &ctinfo);
        if (ct && nf_ct_is_confirmed(ct))
                return true;
#endif
        return false;
}

static inline int ip_vs_register_conntrack(struct ip_vs_service *svc)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
        int afmask = (svc->af == AF_INET6) ? 2 : 1;
        int ret = 0;

        if (!(svc->conntrack_afmask & afmask)) {
                ret = nf_ct_netns_get(svc->ipvs->net, svc->af);
                if (ret >= 0)
                        svc->conntrack_afmask |= afmask;
        }
        return ret;
#else
        return 0;
#endif
}

static inline void ip_vs_unregister_conntrack(struct ip_vs_service *svc)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
        int afmask = (svc->af == AF_INET6) ? 2 : 1;

        if (svc->conntrack_afmask & afmask) {
                nf_ct_netns_put(svc->ipvs->net, svc->af);
                svc->conntrack_afmask &= ~afmask;
        }
#endif
}

int ip_vs_register_hooks(struct netns_ipvs *ipvs, unsigned int af);
void ip_vs_unregister_hooks(struct netns_ipvs *ipvs, unsigned int af);

static inline int
ip_vs_dest_conn_overhead(struct ip_vs_dest *dest)
{
        /* We think the overhead of processing active connections is 256
         * times higher than that of inactive connections in average. (This
         * 256 times might not be accurate, we will change it later) We
         * use the following formula to estimate the overhead now:
         *                dest->activeconns*256 + dest->inactconns
         */
        return (atomic_read(&dest->activeconns) << 8) +
                atomic_read(&dest->inactconns);
}

#ifdef CONFIG_IP_VS_PROTO_TCP
INDIRECT_CALLABLE_DECLARE(int
        tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
                         struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
#endif

#ifdef CONFIG_IP_VS_PROTO_UDP
INDIRECT_CALLABLE_DECLARE(int
        udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
                         struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
#endif
#endif  /* _NET_IP_VS_H */