/* AF_RXRPC internal definitions
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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.
 */

#include <linux/atomic.h>
#include <linux/seqlock.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "protocol.h"

#if 0
#define CHECK_SLAB_OKAY(X)                                   \
        BUG_ON(atomic_read((X)) >> (sizeof(atomic_t) - 2) == \
               (POISON_FREE << 8 | POISON_FREE))
#else
#define CHECK_SLAB_OKAY(X) do {} while (0)
#endif

#define FCRYPT_BSIZE 8
struct rxrpc_crypt {
        union {
                u8      x[FCRYPT_BSIZE];
                __be32  n[2];
        };
} __attribute__((aligned(8)));

#define rxrpc_queue_work(WS)    queue_work(rxrpc_workqueue, (WS))
#define rxrpc_queue_delayed_work(WS,D)  \
        queue_delayed_work(rxrpc_workqueue, (WS), (D))

struct rxrpc_connection;

/*
 * Mark applied to socket buffers.
 */
enum rxrpc_skb_mark {
        RXRPC_SKB_MARK_DATA,            /* data message */
        RXRPC_SKB_MARK_FINAL_ACK,       /* final ACK received message */
        RXRPC_SKB_MARK_BUSY,            /* server busy message */
        RXRPC_SKB_MARK_REMOTE_ABORT,    /* remote abort message */
        RXRPC_SKB_MARK_LOCAL_ABORT,     /* local abort message */
        RXRPC_SKB_MARK_NET_ERROR,       /* network error message */
        RXRPC_SKB_MARK_LOCAL_ERROR,     /* local error message */
        RXRPC_SKB_MARK_NEW_CALL,        /* local error message */
};

/*
 * sk_state for RxRPC sockets
 */
enum {
        RXRPC_UNBOUND = 0,
        RXRPC_CLIENT_UNBOUND,           /* Unbound socket used as client */
        RXRPC_CLIENT_BOUND,             /* client local address bound */
        RXRPC_SERVER_BOUND,             /* server local address bound */
        RXRPC_SERVER_BOUND2,            /* second server local address bound */
        RXRPC_SERVER_LISTENING,         /* server listening for connections */
        RXRPC_SERVER_LISTEN_DISABLED,   /* server listening disabled */
        RXRPC_CLOSE,                    /* socket is being closed */
};

/*
 * Per-network namespace data.
 */
struct rxrpc_net {
        struct proc_dir_entry   *proc_net;      /* Subdir in /proc/net */
        u32                     epoch;          /* Local epoch for detecting local-end reset */
        struct list_head        calls;          /* List of calls active in this namespace */
        rwlock_t                call_lock;      /* Lock for ->calls */

        struct list_head        conn_proc_list; /* List of conns in this namespace for proc */
        struct list_head        service_conns;  /* Service conns in this namespace */
        rwlock_t                conn_lock;      /* Lock for ->conn_proc_list, ->service_conns */
        struct delayed_work     service_conn_reaper;

        unsigned int            nr_client_conns;
        unsigned int            nr_active_client_conns;
        bool                    kill_all_client_conns;
        spinlock_t              client_conn_cache_lock; /* Lock for ->*_client_conns */
        spinlock_t              client_conn_discard_lock; /* Prevent multiple discarders */
        struct list_head        waiting_client_conns;
        struct list_head        active_client_conns;
        struct list_head        idle_client_conns;
        struct delayed_work     client_conn_reaper;

        struct list_head        local_endpoints;
        struct mutex            local_mutex;    /* Lock for ->local_endpoints */

        spinlock_t              peer_hash_lock; /* Lock for ->peer_hash */
        DECLARE_HASHTABLE       (peer_hash, 10);
};

/*
 * Service backlog preallocation.
 *
 * This contains circular buffers of preallocated peers, connections and calls
 * for incoming service calls and their head and tail pointers.  This allows
 * calls to be set up in the data_ready handler, thereby avoiding the need to
 * shuffle packets around so much.
 */
struct rxrpc_backlog {
        unsigned short          peer_backlog_head;
        unsigned short          peer_backlog_tail;
        unsigned short          conn_backlog_head;
        unsigned short          conn_backlog_tail;
        unsigned short          call_backlog_head;
        unsigned short          call_backlog_tail;
#define RXRPC_BACKLOG_MAX       32
        struct rxrpc_peer       *peer_backlog[RXRPC_BACKLOG_MAX];
        struct rxrpc_connection *conn_backlog[RXRPC_BACKLOG_MAX];
        struct rxrpc_call       *call_backlog[RXRPC_BACKLOG_MAX];
};

/*
 * RxRPC socket definition
 */
struct rxrpc_sock {
        /* WARNING: sk has to be the first member */
        struct sock             sk;
        rxrpc_notify_new_call_t notify_new_call; /* Func to notify of new call */
        rxrpc_discard_new_call_t discard_new_call; /* Func to discard a new call */
        struct rxrpc_local      *local;         /* local endpoint */
        struct rxrpc_backlog    *backlog;       /* Preallocation for services */
        spinlock_t              incoming_lock;  /* Incoming call vs service shutdown lock */
        struct list_head        sock_calls;     /* List of calls owned by this socket */
        struct list_head        to_be_accepted; /* calls awaiting acceptance */
        struct list_head        recvmsg_q;      /* Calls awaiting recvmsg's attention  */
        rwlock_t                recvmsg_lock;   /* Lock for recvmsg_q */
        struct key              *key;           /* security for this socket */
        struct key              *securities;    /* list of server security descriptors */
        struct rb_root          calls;          /* User ID -> call mapping */
        unsigned long           flags;
#define RXRPC_SOCK_CONNECTED            0       /* connect_srx is set */
        rwlock_t                call_lock;      /* lock for calls */
        u32                     min_sec_level;  /* minimum security level */
#define RXRPC_SECURITY_MAX      RXRPC_SECURITY_ENCRYPT
        bool                    exclusive;      /* Exclusive connection for a client socket */
        u16                     second_service; /* Additional service bound to the endpoint */
        struct {
                /* Service upgrade information */
                u16             from;           /* Service ID to upgrade (if not 0) */
                u16             to;             /* service ID to upgrade to */
        } service_upgrade;
        sa_family_t             family;         /* Protocol family created with */
        struct sockaddr_rxrpc   srx;            /* Primary Service/local addresses */
        struct sockaddr_rxrpc   connect_srx;    /* Default client address from connect() */
};

#define rxrpc_sk(__sk) container_of((__sk), struct rxrpc_sock, sk)

/*
 * CPU-byteorder normalised Rx packet header.
 */
struct rxrpc_host_header {
        u32             epoch;          /* client boot timestamp */
        u32             cid;            /* connection and channel ID */
        u32             callNumber;     /* call ID (0 for connection-level packets) */
        u32             seq;            /* sequence number of pkt in call stream */
        u32             serial;         /* serial number of pkt sent to network */
        u8              type;           /* packet type */
        u8              flags;          /* packet flags */
        u8              userStatus;     /* app-layer defined status */
        u8              securityIndex;  /* security protocol ID */
        union {
                u16     _rsvd;          /* reserved */
                u16     cksum;          /* kerberos security checksum */
        };
        u16             serviceId;      /* service ID */
} __packed;

/*
 * RxRPC socket buffer private variables
 * - max 48 bytes (struct sk_buff::cb)
 */
struct rxrpc_skb_priv {
        union {
                u8              nr_jumbo;       /* Number of jumbo subpackets */
        };
        union {
                int             remain;         /* amount of space remaining for next write */
        };

        struct rxrpc_host_header hdr;           /* RxRPC packet header from this packet */
};

#define rxrpc_skb(__skb) ((struct rxrpc_skb_priv *) &(__skb)->cb)

/*
 * RxRPC security module interface
 */
struct rxrpc_security {
        const char              *name;          /* name of this service */
        u8                      security_index; /* security type provided */

        /* Initialise a security service */
        int (*init)(void);

        /* Clean up a security service */
        void (*exit)(void);

        /* initialise a connection's security */
        int (*init_connection_security)(struct rxrpc_connection *);

        /* prime a connection's packet security */
        int (*prime_packet_security)(struct rxrpc_connection *);

        /* impose security on a packet */
        int (*secure_packet)(struct rxrpc_call *,
                             struct sk_buff *,
                             size_t,
                             void *);

        /* verify the security on a received packet */
        int (*verify_packet)(struct rxrpc_call *, struct sk_buff *,
                             unsigned int, unsigned int, rxrpc_seq_t, u16);

        /* Locate the data in a received packet that has been verified. */
        void (*locate_data)(struct rxrpc_call *, struct sk_buff *,
                            unsigned int *, unsigned int *);

        /* issue a challenge */
        int (*issue_challenge)(struct rxrpc_connection *);

        /* respond to a challenge */
        int (*respond_to_challenge)(struct rxrpc_connection *,
                                    struct sk_buff *,
                                    u32 *);

        /* verify a response */
        int (*verify_response)(struct rxrpc_connection *,
                               struct sk_buff *,
                               u32 *);

        /* clear connection security */
        void (*clear)(struct rxrpc_connection *);
};

/*
 * RxRPC local transport endpoint description
 * - owned by a single AF_RXRPC socket
 * - pointed to by transport socket struct sk_user_data
 */
struct rxrpc_local {
        struct rcu_head         rcu;
        atomic_t                usage;
        struct rxrpc_net        *rxnet;         /* The network ns in which this resides */
        struct list_head        link;
        struct socket           *socket;        /* my UDP socket */
        struct work_struct      processor;
        struct rxrpc_sock __rcu *service;       /* Service(s) listening on this endpoint */
        struct rw_semaphore     defrag_sem;     /* control re-enablement of IP DF bit */
        struct sk_buff_head     reject_queue;   /* packets awaiting rejection */
        struct sk_buff_head     event_queue;    /* endpoint event packets awaiting processing */
        struct rb_root          client_conns;   /* Client connections by socket params */
        spinlock_t              client_conns_lock; /* Lock for client_conns */
        spinlock_t              lock;           /* access lock */
        rwlock_t                services_lock;  /* lock for services list */
        int                     debug_id;       /* debug ID for printks */
        bool                    dead;
        struct sockaddr_rxrpc   srx;            /* local address */
};

/*
 * RxRPC remote transport endpoint definition
 * - matched by local endpoint, remote port, address and protocol type
 */
struct rxrpc_peer {
        struct rcu_head         rcu;            /* This must be first */
        atomic_t                usage;
        unsigned long           hash_key;
        struct hlist_node       hash_link;
        struct rxrpc_local      *local;
        struct hlist_head       error_targets;  /* targets for net error distribution */
        struct work_struct      error_distributor;
        struct rb_root          service_conns;  /* Service connections */
        seqlock_t               service_conn_lock;
        spinlock_t              lock;           /* access lock */
        unsigned int            if_mtu;         /* interface MTU for this peer */
        unsigned int            mtu;            /* network MTU for this peer */
        unsigned int            maxdata;        /* data size (MTU - hdrsize) */
        unsigned short          hdrsize;        /* header size (IP + UDP + RxRPC) */
        int                     debug_id;       /* debug ID for printks */
        int                     error_report;   /* Net (+0) or local (+1000000) to distribute */
#define RXRPC_LOCAL_ERROR_OFFSET 1000000
        struct sockaddr_rxrpc   srx;            /* remote address */

        /* calculated RTT cache */
#define RXRPC_RTT_CACHE_SIZE 32
        ktime_t                 rtt_last_req;   /* Time of last RTT request */
        u64                     rtt;            /* Current RTT estimate (in nS) */
        u64                     rtt_sum;        /* Sum of cache contents */
        u64                     rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* Determined RTT cache */
        u8                      rtt_cursor;     /* next entry at which to insert */
        u8                      rtt_usage;      /* amount of cache actually used */

        u8                      cong_cwnd;      /* Congestion window size */
};

/*
 * Keys for matching a connection.
 */
struct rxrpc_conn_proto {
        union {
                struct {
                        u32     epoch;          /* epoch of this connection */
                        u32     cid;            /* connection ID */
                };
                u64             index_key;
        };
};

struct rxrpc_conn_parameters {
        struct rxrpc_local      *local;         /* Representation of local endpoint */
        struct rxrpc_peer       *peer;          /* Remote endpoint */
        struct key              *key;           /* Security details */
        bool                    exclusive;      /* T if conn is exclusive */
        bool                    upgrade;        /* T if service ID can be upgraded */
        u16                     service_id;     /* Service ID for this connection */
        u32                     security_level; /* Security level selected */
};

/*
 * Bits in the connection flags.
 */
enum rxrpc_conn_flag {
        RXRPC_CONN_HAS_IDR,             /* Has a client conn ID assigned */
        RXRPC_CONN_IN_SERVICE_CONNS,    /* Conn is in peer->service_conns */
        RXRPC_CONN_IN_CLIENT_CONNS,     /* Conn is in local->client_conns */
        RXRPC_CONN_EXPOSED,             /* Conn has extra ref for exposure */
        RXRPC_CONN_DONT_REUSE,          /* Don't reuse this connection */
        RXRPC_CONN_COUNTED,             /* Counted by rxrpc_nr_client_conns */
        RXRPC_CONN_PROBING_FOR_UPGRADE, /* Probing for service upgrade */
};

/*
 * Events that can be raised upon a connection.
 */
enum rxrpc_conn_event {
        RXRPC_CONN_EV_CHALLENGE,        /* Send challenge packet */
};

/*
 * The connection cache state.
 */
enum rxrpc_conn_cache_state {
        RXRPC_CONN_CLIENT_INACTIVE,     /* Conn is not yet listed */
        RXRPC_CONN_CLIENT_WAITING,      /* Conn is on wait list, waiting for capacity */
        RXRPC_CONN_CLIENT_ACTIVE,       /* Conn is on active list, doing calls */
        RXRPC_CONN_CLIENT_UPGRADE,      /* Conn is on active list, probing for upgrade */
        RXRPC_CONN_CLIENT_CULLED,       /* Conn is culled and delisted, doing calls */
        RXRPC_CONN_CLIENT_IDLE,         /* Conn is on idle list, doing mostly nothing */
        RXRPC_CONN__NR_CACHE_STATES
};

/*
 * The connection protocol state.
 */
enum rxrpc_conn_proto_state {
        RXRPC_CONN_UNUSED,              /* Connection not yet attempted */
        RXRPC_CONN_CLIENT,              /* Client connection */
        RXRPC_CONN_SERVICE_PREALLOC,    /* Service connection preallocation */
        RXRPC_CONN_SERVICE_UNSECURED,   /* Service unsecured connection */
        RXRPC_CONN_SERVICE_CHALLENGING, /* Service challenging for security */
        RXRPC_CONN_SERVICE,             /* Service secured connection */
        RXRPC_CONN_REMOTELY_ABORTED,    /* Conn aborted by peer */
        RXRPC_CONN_LOCALLY_ABORTED,     /* Conn aborted locally */
        RXRPC_CONN__NR_STATES
};

/*
 * RxRPC connection definition
 * - matched by { local, peer, epoch, conn_id, direction }
 * - each connection can only handle four simultaneous calls
 */
struct rxrpc_connection {
        struct rxrpc_conn_proto proto;
        struct rxrpc_conn_parameters params;

        atomic_t                usage;
        struct rcu_head         rcu;
        struct list_head        cache_link;

        spinlock_t              channel_lock;
        unsigned char           active_chans;   /* Mask of active channels */
#define RXRPC_ACTIVE_CHANS_MASK ((1 << RXRPC_MAXCALLS) - 1)
        struct list_head        waiting_calls;  /* Calls waiting for channels */
        struct rxrpc_channel {
                struct rxrpc_call __rcu *call;          /* Active call */
                u32                     call_id;        /* ID of current call */
                u32                     call_counter;   /* Call ID counter */
                u32                     last_call;      /* ID of last call */
                u8                      last_type;      /* Type of last packet */
                union {
                        u32             last_seq;
                        u32             last_abort;
                };
        } channels[RXRPC_MAXCALLS];

        struct work_struct      processor;      /* connection event processor */
        union {
                struct rb_node  client_node;    /* Node in local->client_conns */
                struct rb_node  service_node;   /* Node in peer->service_conns */
        };
        struct list_head        proc_link;      /* link in procfs list */
        struct list_head        link;           /* link in master connection list */
        struct sk_buff_head     rx_queue;       /* received conn-level packets */
        const struct rxrpc_security *security;  /* applied security module */
        struct key              *server_key;    /* security for this service */
        struct crypto_skcipher  *cipher;        /* encryption handle */
        struct rxrpc_crypt      csum_iv;        /* packet checksum base */
        unsigned long           flags;
        unsigned long           events;
        unsigned long           idle_timestamp; /* Time at which last became idle */
        spinlock_t              state_lock;     /* state-change lock */
        enum rxrpc_conn_cache_state cache_state;
        enum rxrpc_conn_proto_state state;      /* current state of connection */
        u32                     local_abort;    /* local abort code */
        u32                     remote_abort;   /* remote abort code */
        int                     debug_id;       /* debug ID for printks */
        atomic_t                serial;         /* packet serial number counter */
        unsigned int            hi_serial;      /* highest serial number received */
        u32                     security_nonce; /* response re-use preventer */
        u16                     service_id;     /* Service ID, possibly upgraded */
        u8                      size_align;     /* data size alignment (for security) */
        u8                      security_size;  /* security header size */
        u8                      security_ix;    /* security type */
        u8                      out_clientflag; /* RXRPC_CLIENT_INITIATED if we are client */
};

/*
 * Flags in call->flags.
 */
enum rxrpc_call_flag {
        RXRPC_CALL_RELEASED,            /* call has been released - no more message to userspace */
        RXRPC_CALL_HAS_USERID,          /* has a user ID attached */
        RXRPC_CALL_IS_SERVICE,          /* Call is service call */
        RXRPC_CALL_EXPOSED,             /* The call was exposed to the world */
        RXRPC_CALL_RX_LAST,             /* Received the last packet (at rxtx_top) */
        RXRPC_CALL_TX_LAST,             /* Last packet in Tx buffer (at rxtx_top) */
        RXRPC_CALL_TX_LASTQ,            /* Last packet has been queued */
        RXRPC_CALL_SEND_PING,           /* A ping will need to be sent */
        RXRPC_CALL_PINGING,             /* Ping in process */
        RXRPC_CALL_RETRANS_TIMEOUT,     /* Retransmission due to timeout occurred */
};

/*
 * Events that can be raised on a call.
 */
enum rxrpc_call_event {
        RXRPC_CALL_EV_ACK,              /* need to generate ACK */
        RXRPC_CALL_EV_ABORT,            /* need to generate abort */
        RXRPC_CALL_EV_TIMER,            /* Timer expired */
        RXRPC_CALL_EV_RESEND,           /* Tx resend required */
        RXRPC_CALL_EV_PING,             /* Ping send required */
};

/*
 * The states that a call can be in.
 */
enum rxrpc_call_state {
        RXRPC_CALL_UNINITIALISED,
        RXRPC_CALL_CLIENT_AWAIT_CONN,   /* - client waiting for connection to become available */
        RXRPC_CALL_CLIENT_SEND_REQUEST, /* - client sending request phase */
        RXRPC_CALL_CLIENT_AWAIT_REPLY,  /* - client awaiting reply */
        RXRPC_CALL_CLIENT_RECV_REPLY,   /* - client receiving reply phase */
        RXRPC_CALL_SERVER_PREALLOC,     /* - service preallocation */
        RXRPC_CALL_SERVER_SECURING,     /* - server securing request connection */
        RXRPC_CALL_SERVER_ACCEPTING,    /* - server accepting request */
        RXRPC_CALL_SERVER_RECV_REQUEST, /* - server receiving request */
        RXRPC_CALL_SERVER_ACK_REQUEST,  /* - server pending ACK of request */
        RXRPC_CALL_SERVER_SEND_REPLY,   /* - server sending reply */
        RXRPC_CALL_SERVER_AWAIT_ACK,    /* - server awaiting final ACK */
        RXRPC_CALL_COMPLETE,            /* - call complete */
        NR__RXRPC_CALL_STATES
};

/*
 * Call Tx congestion management modes.
 */
enum rxrpc_congest_mode {
        RXRPC_CALL_SLOW_START,
        RXRPC_CALL_CONGEST_AVOIDANCE,
        RXRPC_CALL_PACKET_LOSS,
        RXRPC_CALL_FAST_RETRANSMIT,
        NR__RXRPC_CONGEST_MODES
};

/*
 * RxRPC call definition
 * - matched by { connection, call_id }
 */
struct rxrpc_call {
        struct rcu_head         rcu;
        struct rxrpc_connection *conn;          /* connection carrying call */
        struct rxrpc_peer       *peer;          /* Peer record for remote address */
        struct rxrpc_sock __rcu *socket;        /* socket responsible */
        struct mutex            user_mutex;     /* User access mutex */
        ktime_t                 ack_at;         /* When deferred ACK needs to happen */
        ktime_t                 resend_at;      /* When next resend needs to happen */
        ktime_t                 ping_at;        /* When next to send a ping */
        ktime_t                 expire_at;      /* When the call times out */
        struct timer_list       timer;          /* Combined event timer */
        struct work_struct      processor;      /* Event processor */
        rxrpc_notify_rx_t       notify_rx;      /* kernel service Rx notification function */
        struct list_head        link;           /* link in master call list */
        struct list_head        chan_wait_link; /* Link in conn->waiting_calls */
        struct hlist_node       error_link;     /* link in error distribution list */
        struct list_head        accept_link;    /* Link in rx->acceptq */
        struct list_head        recvmsg_link;   /* Link in rx->recvmsg_q */
        struct list_head        sock_link;      /* Link in rx->sock_calls */
        struct rb_node          sock_node;      /* Node in rx->calls */
        struct sk_buff          *tx_pending;    /* Tx socket buffer being filled */
        wait_queue_head_t       waitq;          /* Wait queue for channel or Tx */
        s64                     tx_total_len;   /* Total length left to be transmitted (or -1) */
        __be32                  crypto_buf[2];  /* Temporary packet crypto buffer */
        unsigned long           user_call_ID;   /* user-defined call ID */
        unsigned long           flags;
        unsigned long           events;
        spinlock_t              lock;
        rwlock_t                state_lock;     /* lock for state transition */
        u32                     abort_code;     /* Local/remote abort code */
        int                     error;          /* Local error incurred */
        enum rxrpc_call_state   state;          /* current state of call */
        enum rxrpc_call_completion completion;  /* Call completion condition */
        atomic_t                usage;
        u16                     service_id;     /* service ID */
        u8                      security_ix;    /* Security type */
        u32                     call_id;        /* call ID on connection  */
        u32                     cid;            /* connection ID plus channel index */
        int                     debug_id;       /* debug ID for printks */
        unsigned short          rx_pkt_offset;  /* Current recvmsg packet offset */
        unsigned short          rx_pkt_len;     /* Current recvmsg packet len */

        /* Rx/Tx circular buffer, depending on phase.
         *
         * In the Rx phase, packets are annotated with 0 or the number of the
         * segment of a jumbo packet each buffer refers to.  There can be up to
         * 47 segments in a maximum-size UDP packet.
         *
         * In the Tx phase, packets are annotated with which buffers have been
         * acked.
         */
#define RXRPC_RXTX_BUFF_SIZE    64
#define RXRPC_RXTX_BUFF_MASK    (RXRPC_RXTX_BUFF_SIZE - 1)
#define RXRPC_INIT_RX_WINDOW_SIZE 32
        struct sk_buff          **rxtx_buffer;
        u8                      *rxtx_annotations;
#define RXRPC_TX_ANNO_ACK       0
#define RXRPC_TX_ANNO_UNACK     1
#define RXRPC_TX_ANNO_NAK       2
#define RXRPC_TX_ANNO_RETRANS   3
#define RXRPC_TX_ANNO_MASK      0x03
#define RXRPC_TX_ANNO_LAST      0x04
#define RXRPC_TX_ANNO_RESENT    0x08

#define RXRPC_RX_ANNO_JUMBO     0x3f            /* Jumbo subpacket number + 1 if not zero */
#define RXRPC_RX_ANNO_JLAST     0x40            /* Set if last element of a jumbo packet */
#define RXRPC_RX_ANNO_VERIFIED  0x80            /* Set if verified and decrypted */
        rxrpc_seq_t             tx_hard_ack;    /* Dead slot in buffer; the first transmitted but
                                                 * not hard-ACK'd packet follows this.
                                                 */
        rxrpc_seq_t             tx_top;         /* Highest Tx slot allocated. */

        /* TCP-style slow-start congestion control [RFC5681].  Since the SMSS
         * is fixed, we keep these numbers in terms of segments (ie. DATA
         * packets) rather than bytes.
         */
#define RXRPC_TX_SMSS           RXRPC_JUMBO_DATALEN
        u8                      cong_cwnd;      /* Congestion window size */
        u8                      cong_extra;     /* Extra to send for congestion management */
        u8                      cong_ssthresh;  /* Slow-start threshold */
        enum rxrpc_congest_mode cong_mode:8;    /* Congestion management mode */
        u8                      cong_dup_acks;  /* Count of ACKs showing missing packets */
        u8                      cong_cumul_acks; /* Cumulative ACK count */
        ktime_t                 cong_tstamp;    /* Last time cwnd was changed */

        rxrpc_seq_t             rx_hard_ack;    /* Dead slot in buffer; the first received but not
                                                 * consumed packet follows this.
                                                 */
        rxrpc_seq_t             rx_top;         /* Highest Rx slot allocated. */
        rxrpc_seq_t             rx_expect_next; /* Expected next packet sequence number */
        u8                      rx_winsize;     /* Size of Rx window */
        u8                      tx_winsize;     /* Maximum size of Tx window */
        bool                    tx_phase;       /* T if transmission phase, F if receive phase */
        u8                      nr_jumbo_bad;   /* Number of jumbo dups/exceeds-windows */

        /* receive-phase ACK management */
        u8                      ackr_reason;    /* reason to ACK */
        u16                     ackr_skew;      /* skew on packet being ACK'd */
        rxrpc_serial_t          ackr_serial;    /* serial of packet being ACK'd */
        rxrpc_seq_t             ackr_prev_seq;  /* previous sequence number received */
        rxrpc_seq_t             ackr_consumed;  /* Highest packet shown consumed */
        rxrpc_seq_t             ackr_seen;      /* Highest packet shown seen */

        /* ping management */
        rxrpc_serial_t          ping_serial;    /* Last ping sent */
        ktime_t                 ping_time;      /* Time last ping sent */

        /* transmission-phase ACK management */
        ktime_t                 acks_latest_ts; /* Timestamp of latest ACK received */
        rxrpc_serial_t          acks_latest;    /* serial number of latest ACK received */
        rxrpc_seq_t             acks_lowest_nak; /* Lowest NACK in the buffer (or ==tx_hard_ack) */
};

/*
 * Summary of a new ACK and the changes it made to the Tx buffer packet states.
 */
struct rxrpc_ack_summary {
        u8                      ack_reason;
        u8                      nr_acks;                /* Number of ACKs in packet */
        u8                      nr_nacks;               /* Number of NACKs in packet */
        u8                      nr_new_acks;            /* Number of new ACKs in packet */
        u8                      nr_new_nacks;           /* Number of new NACKs in packet */
        u8                      nr_rot_new_acks;        /* Number of rotated new ACKs */
        bool                    new_low_nack;           /* T if new low NACK found */
        bool                    retrans_timeo;          /* T if reTx due to timeout happened */
        u8                      flight_size;            /* Number of unreceived transmissions */
        /* Place to stash values for tracing */
        enum rxrpc_congest_mode mode:8;
        u8                      cwnd;
        u8                      ssthresh;
        u8                      dup_acks;
        u8                      cumulative_acks;
};

#include <trace/events/rxrpc.h>

/*
 * af_rxrpc.c
 */
extern atomic_t rxrpc_n_tx_skbs, rxrpc_n_rx_skbs;
extern atomic_t rxrpc_debug_id;
extern struct workqueue_struct *rxrpc_workqueue;

/*
 * call_accept.c
 */
int rxrpc_service_prealloc(struct rxrpc_sock *, gfp_t);
void rxrpc_discard_prealloc(struct rxrpc_sock *);
struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *,
                                           struct rxrpc_connection *,
                                           struct sk_buff *);
void rxrpc_accept_incoming_calls(struct rxrpc_local *);
struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *, unsigned long,
                                     rxrpc_notify_rx_t);
int rxrpc_reject_call(struct rxrpc_sock *);

/*
 * call_event.c
 */
void __rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace, ktime_t);
void rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace, ktime_t);
void rxrpc_propose_ACK(struct rxrpc_call *, u8, u16, u32, bool, bool,
                       enum rxrpc_propose_ack_trace);
void rxrpc_process_call(struct work_struct *);

/*
 * call_object.c
 */
extern const char *const rxrpc_call_states[];
extern const char *const rxrpc_call_completions[];
extern unsigned int rxrpc_max_call_lifetime;
extern struct kmem_cache *rxrpc_call_jar;

struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *, unsigned long);
struct rxrpc_call *rxrpc_alloc_call(gfp_t);
struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *,
                                         struct rxrpc_conn_parameters *,
                                         struct sockaddr_rxrpc *,
                                         unsigned long, s64, gfp_t);
int rxrpc_retry_client_call(struct rxrpc_sock *,
                            struct rxrpc_call *,
                            struct rxrpc_conn_parameters *,
                            struct sockaddr_rxrpc *,
                            gfp_t);
void rxrpc_incoming_call(struct rxrpc_sock *, struct rxrpc_call *,
                         struct sk_buff *);
void rxrpc_release_call(struct rxrpc_sock *, struct rxrpc_call *);
int rxrpc_prepare_call_for_retry(struct rxrpc_sock *, struct rxrpc_call *);
void rxrpc_release_calls_on_socket(struct rxrpc_sock *);
bool __rxrpc_queue_call(struct rxrpc_call *);
bool rxrpc_queue_call(struct rxrpc_call *);
void rxrpc_see_call(struct rxrpc_call *);
void rxrpc_get_call(struct rxrpc_call *, enum rxrpc_call_trace);
void rxrpc_put_call(struct rxrpc_call *, enum rxrpc_call_trace);
void rxrpc_cleanup_call(struct rxrpc_call *);
void rxrpc_destroy_all_calls(struct rxrpc_net *);

static inline bool rxrpc_is_service_call(const struct rxrpc_call *call)
{
        return test_bit(RXRPC_CALL_IS_SERVICE, &call->flags);
}

static inline bool rxrpc_is_client_call(const struct rxrpc_call *call)
{
        return !rxrpc_is_service_call(call);
}

/*
 * Transition a call to the complete state.
 */
static inline bool __rxrpc_set_call_completion(struct rxrpc_call *call,
                                               enum rxrpc_call_completion compl,
                                               u32 abort_code,
                                               int error)
{
        if (call->state < RXRPC_CALL_COMPLETE) {
                call->abort_code = abort_code;
                call->error = error;
                call->completion = compl,
                call->state = RXRPC_CALL_COMPLETE;
                wake_up(&call->waitq);
                return true;
        }
        return false;
}

static inline bool rxrpc_set_call_completion(struct rxrpc_call *call,
                                             enum rxrpc_call_completion compl,
                                             u32 abort_code,
                                             int error)
{
        bool ret;

        write_lock_bh(&call->state_lock);
        ret = __rxrpc_set_call_completion(call, compl, abort_code, error);
        write_unlock_bh(&call->state_lock);
        return ret;
}

/*
 * Record that a call successfully completed.
 */
static inline bool __rxrpc_call_completed(struct rxrpc_call *call)
{
        return __rxrpc_set_call_completion(call, RXRPC_CALL_SUCCEEDED, 0, 0);
}

static inline bool rxrpc_call_completed(struct rxrpc_call *call)
{
        bool ret;

        write_lock_bh(&call->state_lock);
        ret = __rxrpc_call_completed(call);
        write_unlock_bh(&call->state_lock);
        return ret;
}

/*
 * Record that a call is locally aborted.
 */
static inline bool __rxrpc_abort_call(const char *why, struct rxrpc_call *call,
                                      rxrpc_seq_t seq,
                                      u32 abort_code, int error)
{
        trace_rxrpc_abort(why, call->cid, call->call_id, seq,
                          abort_code, error);
        return __rxrpc_set_call_completion(call, RXRPC_CALL_LOCALLY_ABORTED,
                                           abort_code, error);
}

static inline bool rxrpc_abort_call(const char *why, struct rxrpc_call *call,
                                    rxrpc_seq_t seq, u32 abort_code, int error)
{
        bool ret;

        write_lock_bh(&call->state_lock);
        ret = __rxrpc_abort_call(why, call, seq, abort_code, error);
        write_unlock_bh(&call->state_lock);
        return ret;
}

/*
 * Abort a call due to a protocol error.
 */
static inline bool __rxrpc_abort_eproto(struct rxrpc_call *call,
                                        struct sk_buff *skb,
                                        const char *eproto_why,
                                        const char *why,
                                        u32 abort_code)
{
        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

        trace_rxrpc_rx_eproto(call, sp->hdr.serial, eproto_why);
        return rxrpc_abort_call(why, call, sp->hdr.seq, abort_code, -EPROTO);
}

#define rxrpc_abort_eproto(call, skb, eproto_why, abort_why, abort_code) \
        __rxrpc_abort_eproto((call), (skb), tracepoint_string(eproto_why), \
                             (abort_why), (abort_code))

/*
 * conn_client.c
 */
extern unsigned int rxrpc_max_client_connections;
extern unsigned int rxrpc_reap_client_connections;
extern unsigned int rxrpc_conn_idle_client_expiry;
extern unsigned int rxrpc_conn_idle_client_fast_expiry;
extern struct idr rxrpc_client_conn_ids;

void rxrpc_destroy_client_conn_ids(void);
int rxrpc_connect_call(struct rxrpc_call *, struct rxrpc_conn_parameters *,
                       struct sockaddr_rxrpc *, gfp_t);
void rxrpc_expose_client_call(struct rxrpc_call *);
void rxrpc_disconnect_client_call(struct rxrpc_call *);
void rxrpc_put_client_conn(struct rxrpc_connection *);
void rxrpc_discard_expired_client_conns(struct work_struct *);
void rxrpc_destroy_all_client_connections(struct rxrpc_net *);

/*
 * conn_event.c
 */
void rxrpc_process_connection(struct work_struct *);

/*
 * conn_object.c
 */
extern unsigned int rxrpc_connection_expiry;

struct rxrpc_connection *rxrpc_alloc_connection(gfp_t);
struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *,
                                                   struct sk_buff *);
void __rxrpc_disconnect_call(struct rxrpc_connection *, struct rxrpc_call *);
void rxrpc_disconnect_call(struct rxrpc_call *);
void rxrpc_kill_connection(struct rxrpc_connection *);
bool rxrpc_queue_conn(struct rxrpc_connection *);
void rxrpc_see_connection(struct rxrpc_connection *);
void rxrpc_get_connection(struct rxrpc_connection *);
struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *);
void rxrpc_put_service_conn(struct rxrpc_connection *);
void rxrpc_service_connection_reaper(struct work_struct *);
void rxrpc_destroy_all_connections(struct rxrpc_net *);

static inline bool rxrpc_conn_is_client(const struct rxrpc_connection *conn)
{
        return conn->out_clientflag;
}

static inline bool rxrpc_conn_is_service(const struct rxrpc_connection *conn)
{
        return !rxrpc_conn_is_client(conn);
}

static inline void rxrpc_put_connection(struct rxrpc_connection *conn)
{
        if (!conn)
                return;

        if (rxrpc_conn_is_client(conn))
                rxrpc_put_client_conn(conn);
        else
                rxrpc_put_service_conn(conn);
}

/*
 * conn_service.c
 */
struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
                                                     struct sk_buff *);
struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *, gfp_t);
void rxrpc_new_incoming_connection(struct rxrpc_sock *,
                                   struct rxrpc_connection *, struct sk_buff *);
void rxrpc_unpublish_service_conn(struct rxrpc_connection *);

/*
 * input.c
 */
void rxrpc_data_ready(struct sock *);

/*
 * insecure.c
 */
extern const struct rxrpc_security rxrpc_no_security;

/*
 * key.c
 */
extern struct key_type key_type_rxrpc;
extern struct key_type key_type_rxrpc_s;

int rxrpc_request_key(struct rxrpc_sock *, char __user *, int);
int rxrpc_server_keyring(struct rxrpc_sock *, char __user *, int);
int rxrpc_get_server_data_key(struct rxrpc_connection *, const void *, time64_t,
                              u32);

/*
 * local_event.c
 */
extern void rxrpc_process_local_events(struct rxrpc_local *);

/*
 * local_object.c
 */
struct rxrpc_local *rxrpc_lookup_local(struct net *, const struct sockaddr_rxrpc *);
void __rxrpc_put_local(struct rxrpc_local *);
void rxrpc_destroy_all_locals(struct rxrpc_net *);

static inline void rxrpc_get_local(struct rxrpc_local *local)
{
        atomic_inc(&local->usage);
}

static inline
struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
{
        return atomic_inc_not_zero(&local->usage) ? local : NULL;
}

static inline void rxrpc_put_local(struct rxrpc_local *local)
{
        if (local && atomic_dec_and_test(&local->usage))
                __rxrpc_put_local(local);
}

static inline void rxrpc_queue_local(struct rxrpc_local *local)
{
        rxrpc_queue_work(&local->processor);
}

/*
 * misc.c
 */
extern unsigned int rxrpc_max_backlog __read_mostly;
extern unsigned int rxrpc_requested_ack_delay;
extern unsigned int rxrpc_soft_ack_delay;
extern unsigned int rxrpc_idle_ack_delay;
extern unsigned int rxrpc_rx_window_size;
extern unsigned int rxrpc_rx_mtu;
extern unsigned int rxrpc_rx_jumbo_max;
extern unsigned int rxrpc_resend_timeout;

extern const s8 rxrpc_ack_priority[];

/*
 * net_ns.c
 */
extern unsigned int rxrpc_net_id;
extern struct pernet_operations rxrpc_net_ops;

static inline struct rxrpc_net *rxrpc_net(struct net *net)
{
        return net_generic(net, rxrpc_net_id);
}

/*
 * output.c
 */
int rxrpc_send_ack_packet(struct rxrpc_call *, bool);
int rxrpc_send_abort_packet(struct rxrpc_call *);
int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *, bool);
void rxrpc_reject_packets(struct rxrpc_local *);

/*
 * peer_event.c
 */
void rxrpc_error_report(struct sock *);
void rxrpc_peer_error_distributor(struct work_struct *);
void rxrpc_peer_add_rtt(struct rxrpc_call *, enum rxrpc_rtt_rx_trace,
                        rxrpc_serial_t, rxrpc_serial_t, ktime_t, ktime_t);

/*
 * peer_object.c
 */
struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *,
                                         const struct sockaddr_rxrpc *);
struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *,
                                     struct sockaddr_rxrpc *, gfp_t);
struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *, gfp_t);
struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *,
                                              struct rxrpc_peer *);

static inline struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
{
        atomic_inc(&peer->usage);
        return peer;
}

static inline
struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
{
        return atomic_inc_not_zero(&peer->usage) ? peer : NULL;
}

extern void __rxrpc_put_peer(struct rxrpc_peer *peer);
static inline void rxrpc_put_peer(struct rxrpc_peer *peer)
{
        if (peer && atomic_dec_and_test(&peer->usage))
                __rxrpc_put_peer(peer);
}

/*
 * proc.c

 */
extern const struct file_operations rxrpc_call_seq_fops;
extern const struct file_operations rxrpc_connection_seq_fops;

/*
 * recvmsg.c
 */
void rxrpc_notify_socket(struct rxrpc_call *);
int rxrpc_recvmsg(struct socket *, struct msghdr *, size_t, int);

/*
 * rxkad.c
 */
#ifdef CONFIG_RXKAD
extern const struct rxrpc_security rxkad;
#endif

/*
 * security.c
 */
int __init rxrpc_init_security(void);
void rxrpc_exit_security(void);
int rxrpc_init_client_conn_security(struct rxrpc_connection *);
int rxrpc_init_server_conn_security(struct rxrpc_connection *);

/*
 * sendmsg.c
 */
int rxrpc_do_sendmsg(struct rxrpc_sock *, struct msghdr *, size_t);

/*
 * skbuff.c
 */
void rxrpc_kernel_data_consumed(struct rxrpc_call *, struct sk_buff *);
void rxrpc_packet_destructor(struct sk_buff *);
void rxrpc_new_skb(struct sk_buff *, enum rxrpc_skb_trace);
void rxrpc_see_skb(struct sk_buff *, enum rxrpc_skb_trace);
void rxrpc_get_skb(struct sk_buff *, enum rxrpc_skb_trace);
void rxrpc_free_skb(struct sk_buff *, enum rxrpc_skb_trace);
void rxrpc_lose_skb(struct sk_buff *, enum rxrpc_skb_trace);
void rxrpc_purge_queue(struct sk_buff_head *);

/*
 * sysctl.c
 */
#ifdef CONFIG_SYSCTL
extern int __init rxrpc_sysctl_init(void);
extern void rxrpc_sysctl_exit(void);
#else
static inline int __init rxrpc_sysctl_init(void) { return 0; }
static inline void rxrpc_sysctl_exit(void) {}
#endif

/*
 * utils.c
 */
int rxrpc_extract_addr_from_skb(struct rxrpc_local *, struct sockaddr_rxrpc *,
                                struct sk_buff *);

static inline bool before(u32 seq1, u32 seq2)
{
        return (s32)(seq1 - seq2) < 0;
}
static inline bool before_eq(u32 seq1, u32 seq2)
{
        return (s32)(seq1 - seq2) <= 0;
}
static inline bool after(u32 seq1, u32 seq2)
{
        return (s32)(seq1 - seq2) > 0;
}
static inline bool after_eq(u32 seq1, u32 seq2)
{
        return (s32)(seq1 - seq2) >= 0;
}

/*
 * debug tracing
 */
extern unsigned int rxrpc_debug;

#define dbgprintk(FMT,...) \
        printk("[%-6.6s] "FMT"\n", current->comm ,##__VA_ARGS__)

#define kenter(FMT,...) dbgprintk("==> %s("FMT")",__func__ ,##__VA_ARGS__)
#define kleave(FMT,...) dbgprintk("<== %s()"FMT"",__func__ ,##__VA_ARGS__)
#define kdebug(FMT,...) dbgprintk("    "FMT ,##__VA_ARGS__)
#define kproto(FMT,...) dbgprintk("### "FMT ,##__VA_ARGS__)
#define knet(FMT,...)   dbgprintk("@@@ "FMT ,##__VA_ARGS__)


#if defined(__KDEBUG)
#define _enter(FMT,...) kenter(FMT,##__VA_ARGS__)
#define _leave(FMT,...) kleave(FMT,##__VA_ARGS__)
#define _debug(FMT,...) kdebug(FMT,##__VA_ARGS__)
#define _proto(FMT,...) kproto(FMT,##__VA_ARGS__)
#define _net(FMT,...)   knet(FMT,##__VA_ARGS__)

#elif defined(CONFIG_AF_RXRPC_DEBUG)
#define RXRPC_DEBUG_KENTER      0x01
#define RXRPC_DEBUG_KLEAVE      0x02
#define RXRPC_DEBUG_KDEBUG      0x04
#define RXRPC_DEBUG_KPROTO      0x08
#define RXRPC_DEBUG_KNET        0x10

#define _enter(FMT,...)                                 \
do {                                                    \
        if (unlikely(rxrpc_debug & RXRPC_DEBUG_KENTER)) \
                kenter(FMT,##__VA_ARGS__);              \
} while (0)

#define _leave(FMT,...)                                 \
do {                                                    \
        if (unlikely(rxrpc_debug & RXRPC_DEBUG_KLEAVE)) \
                kleave(FMT,##__VA_ARGS__);              \
} while (0)

#define _debug(FMT,...)                                 \
do {                                                    \
        if (unlikely(rxrpc_debug & RXRPC_DEBUG_KDEBUG)) \
                kdebug(FMT,##__VA_ARGS__);              \
} while (0)

#define _proto(FMT,...)                                 \
do {                                                    \
        if (unlikely(rxrpc_debug & RXRPC_DEBUG_KPROTO)) \
                kproto(FMT,##__VA_ARGS__);              \
} while (0)

#define _net(FMT,...)                                   \
do {                                                    \
        if (unlikely(rxrpc_debug & RXRPC_DEBUG_KNET))   \
                knet(FMT,##__VA_ARGS__);                \
} while (0)

#else
#define _enter(FMT,...) no_printk("==> %s("FMT")",__func__ ,##__VA_ARGS__)
#define _leave(FMT,...) no_printk("<== %s()"FMT"",__func__ ,##__VA_ARGS__)
#define _debug(FMT,...) no_printk("    "FMT ,##__VA_ARGS__)
#define _proto(FMT,...) no_printk("### "FMT ,##__VA_ARGS__)
#define _net(FMT,...)   no_printk("@@@ "FMT ,##__VA_ARGS__)
#endif

/*
 * debug assertion checking
 */
#if 1 // defined(__KDEBUGALL)

#define ASSERT(X)                                               \
do {                                                            \
        if (unlikely(!(X))) {                                   \
                pr_err("Assertion failed\n");                   \
                BUG();                                          \
        }                                                       \
} while (0)

#define ASSERTCMP(X, OP, Y)                                             \
do {                                                                    \
        __typeof__(X) _x = (X);                                         \
        __typeof__(Y) _y = (__typeof__(X))(Y);                          \
        if (unlikely(!(_x OP _y))) {                                    \
                pr_err("Assertion failed - %lu(0x%lx) %s %lu(0x%lx) is false\n", \
                       (unsigned long)_x, (unsigned long)_x, #OP,       \
                       (unsigned long)_y, (unsigned long)_y);           \
                BUG();                                                  \
        }                                                               \
} while (0)

#define ASSERTIF(C, X)                                          \
do {                                                            \
        if (unlikely((C) && !(X))) {                            \
                pr_err("Assertion failed\n");                   \
                BUG();                                          \
        }                                                       \
} while (0)

#define ASSERTIFCMP(C, X, OP, Y)                                        \
do {                                                                    \
        __typeof__(X) _x = (X);                                         \
        __typeof__(Y) _y = (__typeof__(X))(Y);                          \
        if (unlikely((C) && !(_x OP _y))) {                             \
                pr_err("Assertion failed - %lu(0x%lx) %s %lu(0x%lx) is false\n", \
                       (unsigned long)_x, (unsigned long)_x, #OP,       \
                       (unsigned long)_y, (unsigned long)_y);           \
                BUG();                                                  \
        }                                                               \
} while (0)

#else

#define ASSERT(X)                               \
do {                                            \
} while (0)

#define ASSERTCMP(X, OP, Y)                     \
do {                                            \
} while (0)

#define ASSERTIF(C, X)                          \
do {                                            \
} while (0)

#define ASSERTIFCMP(C, X, OP, Y)                \
do {                                            \
} while (0)

#endif /* __KDEBUGALL */