LXR linux/include/linux/sunrpc/xprt.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 *  linux/include/linux/sunrpc/xprt.h
   4 *
   5 *  Declarations for the RPC transport interface.
   6 *
   7 *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   8 */
   9
  10#ifndef _LINUX_SUNRPC_XPRT_H
  11#define _LINUX_SUNRPC_XPRT_H
  12
  13#include <linux/uio.h>
  14#include <linux/socket.h>
  15#include <linux/in.h>
  16#include <linux/ktime.h>
  17#include <linux/kref.h>
  18#include <linux/sunrpc/sched.h>
  19#include <linux/sunrpc/xdr.h>
  20#include <linux/sunrpc/msg_prot.h>
  21
  22#ifdef __KERNEL__
  23
  24#define RPC_MIN_SLOT_TABLE      (2U)
  25#define RPC_DEF_SLOT_TABLE      (16U)
  26#define RPC_MAX_SLOT_TABLE_LIMIT        (65536U)
  27#define RPC_MAX_SLOT_TABLE      RPC_MAX_SLOT_TABLE_LIMIT
  28
  29#define RPC_CWNDSHIFT           (8U)
  30#define RPC_CWNDSCALE           (1U << RPC_CWNDSHIFT)
  31#define RPC_INITCWND            RPC_CWNDSCALE
  32#define RPC_MAXCWND(xprt)       ((xprt)->max_reqs << RPC_CWNDSHIFT)
  33#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
  34
  35/*
  36 * This describes a timeout strategy
  37 */
  38struct rpc_timeout {
  39        unsigned long           to_initval,             /* initial timeout */
  40                                to_maxval,              /* max timeout */
  41                                to_increment;           /* if !exponential */
  42        unsigned int            to_retries;             /* max # of retries */
  43        unsigned char           to_exponential;
  44};
  45
  46enum rpc_display_format_t {
  47        RPC_DISPLAY_ADDR = 0,
  48        RPC_DISPLAY_PORT,
  49        RPC_DISPLAY_PROTO,
  50        RPC_DISPLAY_HEX_ADDR,
  51        RPC_DISPLAY_HEX_PORT,
  52        RPC_DISPLAY_NETID,
  53        RPC_DISPLAY_MAX,
  54};
  55
  56struct rpc_task;
  57struct rpc_xprt;
  58struct seq_file;
  59struct svc_serv;
  60struct net;
  61
  62/*
  63 * This describes a complete RPC request
  64 */
  65struct rpc_rqst {
  66        /*
  67         * This is the user-visible part
  68         */
  69        struct rpc_xprt *       rq_xprt;                /* RPC client */
  70        struct xdr_buf          rq_snd_buf;             /* send buffer */
  71        struct xdr_buf          rq_rcv_buf;             /* recv buffer */
  72
  73        /*
  74         * This is the private part
  75         */
  76        struct rpc_task *       rq_task;        /* RPC task data */
  77        struct rpc_cred *       rq_cred;        /* Bound cred */
  78        __be32                  rq_xid;         /* request XID */
  79        int                     rq_cong;        /* has incremented xprt->cong */
  80        u32                     rq_seqno;       /* gss seq no. used on req. */
  81        int                     rq_enc_pages_num;
  82        struct page             **rq_enc_pages; /* scratch pages for use by
  83                                                   gss privacy code */
  84        void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
  85        struct list_head        rq_list;
  86
  87        void                    *rq_xprtdata;   /* Per-xprt private data */
  88        void                    *rq_buffer;     /* Call XDR encode buffer */
  89        size_t                  rq_callsize;
  90        void                    *rq_rbuffer;    /* Reply XDR decode buffer */
  91        size_t                  rq_rcvsize;
  92        size_t                  rq_xmit_bytes_sent;     /* total bytes sent */
  93        size_t                  rq_reply_bytes_recvd;   /* total reply bytes */
  94                                                        /* received */
  95
  96        struct xdr_buf          rq_private_buf;         /* The receive buffer
  97                                                         * used in the softirq.
  98                                                         */
  99        unsigned long           rq_majortimeo;  /* major timeout alarm */
 100        unsigned long           rq_timeout;     /* Current timeout value */
 101        ktime_t                 rq_rtt;         /* round-trip time */
 102        unsigned int            rq_retries;     /* # of retries */
 103        unsigned int            rq_connect_cookie;
 104                                                /* A cookie used to track the
 105                                                   state of the transport
 106                                                   connection */
 107        
 108        /*
 109         * Partial send handling
 110         */
 111        u32                     rq_bytes_sent;  /* Bytes we have sent */
 112
 113        ktime_t                 rq_xtime;       /* transmit time stamp */
 114        int                     rq_ntrans;
 115
 116#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 117        struct list_head        rq_bc_list;     /* Callback service list */
 118        unsigned long           rq_bc_pa_state; /* Backchannel prealloc state */
 119        struct list_head        rq_bc_pa_list;  /* Backchannel prealloc list */
 120#endif /* CONFIG_SUNRPC_BACKCHANEL */
 121};
 122#define rq_svec                 rq_snd_buf.head
 123#define rq_slen                 rq_snd_buf.len
 124
 125struct rpc_xprt_ops {
 126        void            (*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
 127        int             (*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 128        void            (*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 129        void            (*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
 130        void            (*rpcbind)(struct rpc_task *task);
 131        void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
 132        void            (*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
 133        int             (*buf_alloc)(struct rpc_task *task);
 134        void            (*buf_free)(struct rpc_task *task);
 135        int             (*send_request)(struct rpc_task *task);
 136        void            (*set_retrans_timeout)(struct rpc_task *task);
 137        void            (*timer)(struct rpc_xprt *xprt, struct rpc_task *task);
 138        void            (*release_request)(struct rpc_task *task);
 139        void            (*close)(struct rpc_xprt *xprt);
 140        void            (*destroy)(struct rpc_xprt *xprt);
 141        void            (*set_connect_timeout)(struct rpc_xprt *xprt,
 142                                        unsigned long connect_timeout,
 143                                        unsigned long reconnect_timeout);
 144        void            (*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
 145        int             (*enable_swap)(struct rpc_xprt *xprt);
 146        void            (*disable_swap)(struct rpc_xprt *xprt);
 147        void            (*inject_disconnect)(struct rpc_xprt *xprt);
 148        int             (*bc_setup)(struct rpc_xprt *xprt,
 149                                    unsigned int min_reqs);
 150        int             (*bc_up)(struct svc_serv *serv, struct net *net);
 151        size_t          (*bc_maxpayload)(struct rpc_xprt *xprt);
 152        void            (*bc_free_rqst)(struct rpc_rqst *rqst);
 153        void            (*bc_destroy)(struct rpc_xprt *xprt,
 154                                      unsigned int max_reqs);
 155};
 156
 157/*
 158 * RPC transport identifiers
 159 *
 160 * To preserve compatibility with the historical use of raw IP protocol
 161 * id's for transport selection, UDP and TCP identifiers are specified
 162 * with the previous values. No such restriction exists for new transports,
 163 * except that they may not collide with these values (17 and 6,
 164 * respectively).
 165 */
 166#define XPRT_TRANSPORT_BC       (1 << 31)
 167enum xprt_transports {
 168        XPRT_TRANSPORT_UDP      = IPPROTO_UDP,
 169        XPRT_TRANSPORT_TCP      = IPPROTO_TCP,
 170        XPRT_TRANSPORT_BC_TCP   = IPPROTO_TCP | XPRT_TRANSPORT_BC,
 171        XPRT_TRANSPORT_RDMA     = 256,
 172        XPRT_TRANSPORT_BC_RDMA  = XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
 173        XPRT_TRANSPORT_LOCAL    = 257,
 174};
 175
 176struct rpc_xprt {
 177        struct kref             kref;           /* Reference count */
 178        const struct rpc_xprt_ops *ops;         /* transport methods */
 179
 180        const struct rpc_timeout *timeout;      /* timeout parms */
 181        struct sockaddr_storage addr;           /* server address */
 182        size_t                  addrlen;        /* size of server address */
 183        int                     prot;           /* IP protocol */
 184
 185        unsigned long           cong;           /* current congestion */
 186        unsigned long           cwnd;           /* congestion window */
 187
 188        size_t                  max_payload;    /* largest RPC payload size,
 189                                                   in bytes */
 190        unsigned int            tsh_size;       /* size of transport specific
 191                                                   header */
 192
 193        struct rpc_wait_queue   binding;        /* requests waiting on rpcbind */
 194        struct rpc_wait_queue   sending;        /* requests waiting to send */
 195        struct rpc_wait_queue   pending;        /* requests in flight */
 196        struct rpc_wait_queue   backlog;        /* waiting for slot */
 197        struct list_head        free;           /* free slots */
 198        unsigned int            max_reqs;       /* max number of slots */
 199        unsigned int            min_reqs;       /* min number of slots */
 200        atomic_t                num_reqs;       /* total slots */
 201        unsigned long           state;          /* transport state */
 202        unsigned char           resvport   : 1; /* use a reserved port */
 203        atomic_t                swapper;        /* we're swapping over this
 204                                                   transport */
 205        unsigned int            bind_index;     /* bind function index */
 206
 207        /*
 208         * Multipath
 209         */
 210        struct list_head        xprt_switch;
 211
 212        /*
 213         * Connection of transports
 214         */
 215        unsigned long           bind_timeout,
 216                                reestablish_timeout;
 217        unsigned int            connect_cookie; /* A cookie that gets bumped
 218                                                   every time the transport
 219                                                   is reconnected */
 220
 221        /*
 222         * Disconnection of idle transports
 223         */
 224        struct work_struct      task_cleanup;
 225        struct timer_list       timer;
 226        unsigned long           last_used,
 227                                idle_timeout,
 228                                connect_timeout,
 229                                max_reconnect_timeout;
 230
 231        /*
 232         * Send stuff
 233         */
 234        spinlock_t              transport_lock; /* lock transport info */
 235        spinlock_t              reserve_lock;   /* lock slot table */
 236        spinlock_t              recv_lock;      /* lock receive list */
 237        u32                     xid;            /* Next XID value to use */
 238        struct rpc_task *       snd_task;       /* Task blocked in send */
 239        struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 240#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 241        struct svc_serv         *bc_serv;       /* The RPC service which will */
 242                                                /* process the callback */
 243        int                     bc_alloc_count; /* Total number of preallocs */
 244        atomic_t                bc_free_slots;
 245        spinlock_t              bc_pa_lock;     /* Protects the preallocated
 246                                                 * items */
 247        struct list_head        bc_pa_list;     /* List of preallocated
 248                                                 * backchannel rpc_rqst's */
 249#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 250        struct list_head        recv;
 251
 252        struct {
 253                unsigned long           bind_count,     /* total number of binds */
 254                                        connect_count,  /* total number of connects */
 255                                        connect_start,  /* connect start timestamp */
 256                                        connect_time,   /* jiffies waiting for connect */
 257                                        sends,          /* how many complete requests */
 258                                        recvs,          /* how many complete requests */
 259                                        bad_xids,       /* lookup_rqst didn't find XID */
 260                                        max_slots;      /* max rpc_slots used */
 261
 262                unsigned long long      req_u,          /* average requests on the wire */
 263                                        bklog_u,        /* backlog queue utilization */
 264                                        sending_u,      /* send q utilization */
 265                                        pending_u;      /* pend q utilization */
 266        } stat;
 267
 268        struct net              *xprt_net;
 269        const char              *servername;
 270        const char              *address_strings[RPC_DISPLAY_MAX];
 271#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 272        struct dentry           *debugfs;               /* debugfs directory */
 273        atomic_t                inject_disconnect;
 274#endif
 275        struct rcu_head         rcu;
 276};
 277
 278#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 279/*
 280 * Backchannel flags
 281 */
 282#define RPC_BC_PA_IN_USE        0x0001          /* Preallocated backchannel */
 283                                                /* buffer in use */
 284#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 285
 286#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 287static inline int bc_prealloc(struct rpc_rqst *req)
 288{
 289        return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 290}
 291#else
 292static inline int bc_prealloc(struct rpc_rqst *req)
 293{
 294        return 0;
 295}
 296#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 297
 298#define XPRT_CREATE_INFINITE_SLOTS      (1U)
 299#define XPRT_CREATE_NO_IDLE_TIMEOUT     (1U << 1)
 300
 301struct xprt_create {
 302        int                     ident;          /* XPRT_TRANSPORT identifier */
 303        struct net *            net;
 304        struct sockaddr *       srcaddr;        /* optional local address */
 305        struct sockaddr *       dstaddr;        /* remote peer address */
 306        size_t                  addrlen;
 307        const char              *servername;
 308        struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 309        struct rpc_xprt_switch  *bc_xps;
 310        unsigned int            flags;
 311};
 312
 313struct xprt_class {
 314        struct list_head        list;
 315        int                     ident;          /* XPRT_TRANSPORT identifier */
 316        struct rpc_xprt *       (*setup)(struct xprt_create *);
 317        struct module           *owner;
 318        char                    name[32];
 319};
 320
 321/*
 322 * Generic internal transport functions
 323 */
 324struct rpc_xprt         *xprt_create_transport(struct xprt_create *args);
 325void                    xprt_connect(struct rpc_task *task);
 326void                    xprt_reserve(struct rpc_task *task);
 327void                    xprt_retry_reserve(struct rpc_task *task);
 328int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 329int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 330void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 331void                    xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 332bool                    xprt_prepare_transmit(struct rpc_task *task);
 333void                    xprt_transmit(struct rpc_task *task);
 334void                    xprt_end_transmit(struct rpc_task *task);
 335int                     xprt_adjust_timeout(struct rpc_rqst *req);
 336void                    xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 337void                    xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 338void                    xprt_release(struct rpc_task *task);
 339struct rpc_xprt *       xprt_get(struct rpc_xprt *xprt);
 340void                    xprt_put(struct rpc_xprt *xprt);
 341struct rpc_xprt *       xprt_alloc(struct net *net, size_t size,
 342                                unsigned int num_prealloc,
 343                                unsigned int max_req);
 344void                    xprt_free(struct rpc_xprt *);
 345
 346static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
 347{
 348        return p + xprt->tsh_size;
 349}
 350
 351static inline int
 352xprt_enable_swap(struct rpc_xprt *xprt)
 353{
 354        return xprt->ops->enable_swap(xprt);
 355}
 356
 357static inline void
 358xprt_disable_swap(struct rpc_xprt *xprt)
 359{
 360        xprt->ops->disable_swap(xprt);
 361}
 362
 363/*
 364 * Transport switch helper functions
 365 */
 366int                     xprt_register_transport(struct xprt_class *type);
 367int                     xprt_unregister_transport(struct xprt_class *type);
 368int                     xprt_load_transport(const char *);
 369void                    xprt_set_retrans_timeout_def(struct rpc_task *task);
 370void                    xprt_set_retrans_timeout_rtt(struct rpc_task *task);
 371void                    xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 372void                    xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
 373void                    xprt_write_space(struct rpc_xprt *xprt);
 374void                    xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 375struct rpc_rqst *       xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 376void                    xprt_complete_rqst(struct rpc_task *task, int copied);
 377void                    xprt_pin_rqst(struct rpc_rqst *req);
 378void                    xprt_unpin_rqst(struct rpc_rqst *req);
 379void                    xprt_release_rqst_cong(struct rpc_task *task);
 380void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 381void                    xprt_force_disconnect(struct rpc_xprt *xprt);
 382void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 383
 384bool                    xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 385void                    xprt_unlock_connect(struct rpc_xprt *, void *);
 386
 387/*
 388 * Reserved bit positions in xprt->state
 389 */
 390#define XPRT_LOCKED             (0)
 391#define XPRT_CONNECTED          (1)
 392#define XPRT_CONNECTING         (2)
 393#define XPRT_CLOSE_WAIT         (3)
 394#define XPRT_BOUND              (4)
 395#define XPRT_BINDING            (5)
 396#define XPRT_CLOSING            (6)
 397#define XPRT_CONGESTED          (9)
 398
 399static inline void xprt_set_connected(struct rpc_xprt *xprt)
 400{
 401        set_bit(XPRT_CONNECTED, &xprt->state);
 402}
 403
 404static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 405{
 406        clear_bit(XPRT_CONNECTED, &xprt->state);
 407}
 408
 409static inline int xprt_connected(struct rpc_xprt *xprt)
 410{
 411        return test_bit(XPRT_CONNECTED, &xprt->state);
 412}
 413
 414static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 415{
 416        return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 417}
 418
 419static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 420{
 421        return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 422}
 423
 424static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 425{
 426        smp_mb__before_atomic();
 427        clear_bit(XPRT_CONNECTING, &xprt->state);
 428        smp_mb__after_atomic();
 429}
 430
 431static inline int xprt_connecting(struct rpc_xprt *xprt)
 432{
 433        return test_bit(XPRT_CONNECTING, &xprt->state);
 434}
 435
 436static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 437{
 438        return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 439}
 440
 441static inline void xprt_set_bound(struct rpc_xprt *xprt)
 442{
 443        test_and_set_bit(XPRT_BOUND, &xprt->state);
 444}
 445
 446static inline int xprt_bound(struct rpc_xprt *xprt)
 447{
 448        return test_bit(XPRT_BOUND, &xprt->state);
 449}
 450
 451static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 452{
 453        clear_bit(XPRT_BOUND, &xprt->state);
 454}
 455
 456static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 457{
 458        smp_mb__before_atomic();
 459        clear_bit(XPRT_BINDING, &xprt->state);
 460        smp_mb__after_atomic();
 461}
 462
 463static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 464{
 465        return test_and_set_bit(XPRT_BINDING, &xprt->state);
 466}
 467
 468#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 469extern unsigned int rpc_inject_disconnect;
 470static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 471{
 472        if (!rpc_inject_disconnect)
 473                return;
 474        if (atomic_dec_return(&xprt->inject_disconnect))
 475                return;
 476        atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 477        xprt->ops->inject_disconnect(xprt);
 478}
 479#else
 480static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 481{
 482}
 483#endif
 484
 485#endif /* __KERNEL__*/
 486
 487#endif /* _LINUX_SUNRPC_XPRT_H */
 488