/*
 * NET          Generic infrastructure for INET connection oriented protocols.
 *
 *              Definitions for inet_connection_sock 
 *
 * Authors:     Many people, see the TCP sources
 *
 *              From code originally in TCP
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 */
#ifndef _INET_CONNECTION_SOCK_H
#define _INET_CONNECTION_SOCK_H

#include <linux/compiler.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/poll.h>

#include <net/inet_sock.h>
#include <net/request_sock.h>

#define INET_CSK_DEBUG 1

/* Cancel timers, when they are not required. */
#undef INET_CSK_CLEAR_TIMERS

struct inet_bind_bucket;
struct tcp_congestion_ops;

/*
 * Pointers to address related TCP functions
 * (i.e. things that depend on the address family)
 */
struct inet_connection_sock_af_ops {
        int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
        void        (*send_check)(struct sock *sk, struct sk_buff *skb);
        int         (*rebuild_header)(struct sock *sk);
        void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
        int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
        struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
                                      struct request_sock *req,
                                      struct dst_entry *dst);
        u16         net_header_len;
        u16         net_frag_header_len;
        u16         sockaddr_len;
        int         (*setsockopt)(struct sock *sk, int level, int optname, 
                                  char __user *optval, unsigned int optlen);
        int         (*getsockopt)(struct sock *sk, int level, int optname, 
                                  char __user *optval, int __user *optlen);
#ifdef CONFIG_COMPAT
        int         (*compat_setsockopt)(struct sock *sk,
                                int level, int optname,
                                char __user *optval, unsigned int optlen);
        int         (*compat_getsockopt)(struct sock *sk,
                                int level, int optname,
                                char __user *optval, int __user *optlen);
#endif
        void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
        int         (*bind_conflict)(const struct sock *sk,
                                     const struct inet_bind_bucket *tb, bool relax);
        void        (*mtu_reduced)(struct sock *sk);
};

/** inet_connection_sock - INET connection oriented sock
 *
 * @icsk_accept_queue:     FIFO of established children 
 * @icsk_bind_hash:        Bind node
 * @icsk_timeout:          Timeout
 * @icsk_retransmit_timer: Resend (no ack)
 * @icsk_rto:              Retransmit timeout
 * @icsk_pmtu_cookie       Last pmtu seen by socket
 * @icsk_ca_ops            Pluggable congestion control hook
 * @icsk_af_ops            Operations which are AF_INET{4,6} specific
 * @icsk_ca_state:         Congestion control state
 * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
 * @icsk_pending:          Scheduled timer event
 * @icsk_backoff:          Backoff
 * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
 * @icsk_probes_out:       unanswered 0 window probes
 * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
 * @icsk_ack:              Delayed ACK control data
 * @icsk_mtup;             MTU probing control data
 */
struct inet_connection_sock {
        /* inet_sock has to be the first member! */
        struct inet_sock          icsk_inet;
        struct request_sock_queue icsk_accept_queue;
        struct inet_bind_bucket   *icsk_bind_hash;
        unsigned long             icsk_timeout;
        struct timer_list         icsk_retransmit_timer;
        struct timer_list         icsk_delack_timer;
        __u32                     icsk_rto;
        __u32                     icsk_pmtu_cookie;
        const struct tcp_congestion_ops *icsk_ca_ops;
        const struct inet_connection_sock_af_ops *icsk_af_ops;
        unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
        __u8                      icsk_ca_state;
        __u8                      icsk_retransmits;
        __u8                      icsk_pending;
        __u8                      icsk_backoff;
        __u8                      icsk_syn_retries;
        __u8                      icsk_probes_out;
        __u16                     icsk_ext_hdr_len;
        struct {
                __u8              pending;       /* ACK is pending                         */
                __u8              quick;         /* Scheduled number of quick acks         */
                __u8              pingpong;      /* The session is interactive             */
                __u8              blocked;       /* Delayed ACK was blocked by socket lock */
                __u32             ato;           /* Predicted tick of soft clock           */
                unsigned long     timeout;       /* Currently scheduled timeout            */
                __u32             lrcvtime;      /* timestamp of last received data packet */
                __u16             last_seg_size; /* Size of last incoming segment          */
                __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */ 
        } icsk_ack;
        struct {
                int               enabled;

                /* Range of MTUs to search */
                int               search_high;
                int               search_low;

                /* Information on the current probe. */
                int               probe_size;
        } icsk_mtup;
        u32                       icsk_ca_priv[16];
        u32                       icsk_user_timeout;
#define ICSK_CA_PRIV_SIZE       (16 * sizeof(u32))
};

#define ICSK_TIME_RETRANS       1       /* Retransmit timer */
#define ICSK_TIME_DACK          2       /* Delayed ack timer */
#define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
#define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
#define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */

static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
{
        return (struct inet_connection_sock *)sk;
}

static inline void *inet_csk_ca(const struct sock *sk)
{
        return (void *)inet_csk(sk)->icsk_ca_priv;
}

struct sock *inet_csk_clone_lock(const struct sock *sk,
                                 const struct request_sock *req,
                                 const gfp_t priority);

enum inet_csk_ack_state_t {
        ICSK_ACK_SCHED  = 1,
        ICSK_ACK_TIMER  = 2,
        ICSK_ACK_PUSHED = 4,
        ICSK_ACK_PUSHED2 = 8
};

void inet_csk_init_xmit_timers(struct sock *sk,
                               void (*retransmit_handler)(unsigned long),
                               void (*delack_handler)(unsigned long),
                               void (*keepalive_handler)(unsigned long));
void inet_csk_clear_xmit_timers(struct sock *sk);

static inline void inet_csk_schedule_ack(struct sock *sk)
{
        inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
}

static inline int inet_csk_ack_scheduled(const struct sock *sk)
{
        return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
}

static inline void inet_csk_delack_init(struct sock *sk)
{
        memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
}

void inet_csk_delete_keepalive_timer(struct sock *sk);
void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);

#ifdef INET_CSK_DEBUG
extern const char inet_csk_timer_bug_msg[];
#endif

static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
{
        struct inet_connection_sock *icsk = inet_csk(sk);
        
        if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
                icsk->icsk_pending = 0;
#ifdef INET_CSK_CLEAR_TIMERS
                sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
#endif
        } else if (what == ICSK_TIME_DACK) {
                icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
#ifdef INET_CSK_CLEAR_TIMERS
                sk_stop_timer(sk, &icsk->icsk_delack_timer);
#endif
        }
#ifdef INET_CSK_DEBUG
        else {
                pr_debug("%s", inet_csk_timer_bug_msg);
        }
#endif
}

/*
 *      Reset the retransmission timer
 */
static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
                                             unsigned long when,
                                             const unsigned long max_when)
{
        struct inet_connection_sock *icsk = inet_csk(sk);

        if (when > max_when) {
#ifdef INET_CSK_DEBUG
                pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
                         sk, what, when, current_text_addr());
#endif
                when = max_when;
        }

        if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
            what == ICSK_TIME_EARLY_RETRANS || what ==  ICSK_TIME_LOSS_PROBE) {
                icsk->icsk_pending = what;
                icsk->icsk_timeout = jiffies + when;
                sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
        } else if (what == ICSK_TIME_DACK) {
                icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
                icsk->icsk_ack.timeout = jiffies + when;
                sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
        }
#ifdef INET_CSK_DEBUG
        else {
                pr_debug("%s", inet_csk_timer_bug_msg);
        }
#endif
}

static inline unsigned long
inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
                     unsigned long max_when)
{
        u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;

        return (unsigned long)min_t(u64, when, max_when);
}

struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);

struct request_sock *inet_csk_search_req(const struct sock *sk,
                                         struct request_sock ***prevp,
                                         const __be16 rport,
                                         const __be32 raddr,
                                         const __be32 laddr);
int inet_csk_bind_conflict(const struct sock *sk,
                           const struct inet_bind_bucket *tb, bool relax);
int inet_csk_get_port(struct sock *sk, unsigned short snum);

struct dst_entry *inet_csk_route_req(struct sock *sk, struct flowi4 *fl4,
                                     const struct request_sock *req);
struct dst_entry *inet_csk_route_child_sock(struct sock *sk, struct sock *newsk,
                                            const struct request_sock *req);

static inline void inet_csk_reqsk_queue_add(struct sock *sk,
                                            struct request_sock *req,
                                            struct sock *child)
{
        reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
}

void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
                                   unsigned long timeout);

static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
                                                struct request_sock *req)
{
        if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
                inet_csk_delete_keepalive_timer(sk);
}

static inline void inet_csk_reqsk_queue_added(struct sock *sk,
                                              const unsigned long timeout)
{
        if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
                inet_csk_reset_keepalive_timer(sk, timeout);
}

static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
{
        return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
}

static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
{
        return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
}

static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
{
        return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
}

static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
                                               struct request_sock *req,
                                               struct request_sock **prev)
{
        reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
}

static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
                                             struct request_sock *req,
                                             struct request_sock **prev)
{
        inet_csk_reqsk_queue_unlink(sk, req, prev);
        inet_csk_reqsk_queue_removed(sk, req);
        reqsk_free(req);
}

void inet_csk_reqsk_queue_prune(struct sock *parent,
                                const unsigned long interval,
                                const unsigned long timeout,
                                const unsigned long max_rto);

void inet_csk_destroy_sock(struct sock *sk);
void inet_csk_prepare_forced_close(struct sock *sk);

/*
 * LISTEN is a special case for poll..
 */
static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
{
        return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
                        (POLLIN | POLLRDNORM) : 0;
}

int inet_csk_listen_start(struct sock *sk, const int nr_table_entries);
void inet_csk_listen_stop(struct sock *sk);

void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);

int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
                               char __user *optval, int __user *optlen);
int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
                               char __user *optval, unsigned int optlen);

struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
#endif /* _INET_CONNECTION_SOCK_H */