clnt4xdr.c

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/*
 * linux/fs/lockd/clnt4xdr.c
 *
 * XDR functions to encode/decode NLM version 4 RPC arguments and results.
 *
 * NLM client-side only.
 *
 * Copyright (C) 2010, Oracle.  All rights reserved.
 */

#include <linux/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/lockd/lockd.h>

#define NLMDBG_FACILITY     NLMDBG_XDR

#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
#  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
#endif

#if (NLMCLNT_OHSIZE > NLM_MAXSTRLEN)
#  error "NLM host name cannot be larger than NLM's maximum string length!"
#endif

/*
 * Declare the space requirements for NLM arguments and replies as
 * number of 32bit-words
 */
#define NLM4_void_sz        (0)
#define NLM4_cookie_sz      (1+(NLM_MAXCOOKIELEN>>2))
#define NLM4_caller_sz      (1+(NLMCLNT_OHSIZE>>2))
#define NLM4_owner_sz       (1+(NLMCLNT_OHSIZE>>2))
#define NLM4_fhandle_sz     (1+(NFS3_FHSIZE>>2))
#define NLM4_lock_sz        (5+NLM4_caller_sz+NLM4_owner_sz+NLM4_fhandle_sz)
#define NLM4_holder_sz      (6+NLM4_owner_sz)

#define NLM4_testargs_sz    (NLM4_cookie_sz+1+NLM4_lock_sz)
#define NLM4_lockargs_sz    (NLM4_cookie_sz+4+NLM4_lock_sz)
#define NLM4_cancargs_sz    (NLM4_cookie_sz+2+NLM4_lock_sz)
#define NLM4_unlockargs_sz  (NLM4_cookie_sz+NLM4_lock_sz)

#define NLM4_testres_sz     (NLM4_cookie_sz+1+NLM4_holder_sz)
#define NLM4_res_sz     (NLM4_cookie_sz+1)
#define NLM4_norep_sz       (0)


static s64 loff_t_to_s64(loff_t offset)
{
    s64 res;

    if (offset >= NLM4_OFFSET_MAX)
        res = NLM4_OFFSET_MAX;
    else if (offset <= -NLM4_OFFSET_MAX)
        res = -NLM4_OFFSET_MAX;
    else
        res = offset;
    return res;
}

static void nlm4_compute_offsets(const struct nlm_lock *lock,
                 u64 *l_offset, u64 *l_len)
{
    const struct file_lock *fl = &lock->fl;

    BUG_ON(fl->fl_start > NLM4_OFFSET_MAX);
    BUG_ON(fl->fl_end > NLM4_OFFSET_MAX &&
                fl->fl_end != OFFSET_MAX);

    *l_offset = loff_t_to_s64(fl->fl_start);
    if (fl->fl_end == OFFSET_MAX)
        *l_len = 0;
    else
        *l_len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1);
}

/*
 * Handle decode buffer overflows out-of-line.
 */
static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
{
    dprintk("lockd: %s prematurely hit the end of our receive buffer. "
        "Remaining buffer length is %tu words.\n",
        func, xdr->end - xdr->p);
}


/*
 * Encode/decode NLMv4 basic data types
 *
 * Basic NLMv4 data types are defined in Appendix II, section 6.1.4
 * of RFC 1813: "NFS Version 3 Protocol Specification" and in Chapter
 * 10 of X/Open's "Protocols for Interworking: XNFS, Version 3W".
 *
 * Not all basic data types have their own encoding and decoding
 * functions.  For run-time efficiency, some data types are encoded
 * or decoded inline.
 */

static void encode_bool(struct xdr_stream *xdr, const int value)
{
    __be32 *p;

    p = xdr_reserve_space(xdr, 4);
    *p = value ? xdr_one : xdr_zero;
}

static void encode_int32(struct xdr_stream *xdr, const s32 value)
{
    __be32 *p;

    p = xdr_reserve_space(xdr, 4);
    *p = cpu_to_be32(value);
}

/*
 *  typedef opaque netobj<MAXNETOBJ_SZ>
 */
static void encode_netobj(struct xdr_stream *xdr,
              const u8 *data, const unsigned int length)
{
    __be32 *p;

    BUG_ON(length > XDR_MAX_NETOBJ);
    p = xdr_reserve_space(xdr, 4 + length);
    xdr_encode_opaque(p, data, length);
}

static int decode_netobj(struct xdr_stream *xdr,
             struct xdr_netobj *obj)
{
    u32 length;
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        goto out_overflow;
    length = be32_to_cpup(p++);
    if (unlikely(length > XDR_MAX_NETOBJ))
        goto out_size;
    obj->len = length;
    obj->data = (u8 *)p;
    return 0;
out_size:
    dprintk("NFS: returned netobj was too long: %u\n", length);
    return -EIO;
out_overflow:
    print_overflow_msg(__func__, xdr);
    return -EIO;
}

/*
 *  netobj cookie;
 */
static void encode_cookie(struct xdr_stream *xdr,
              const struct nlm_cookie *cookie)
{
    BUG_ON(cookie->len > NLM_MAXCOOKIELEN);
    encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
}

static int decode_cookie(struct xdr_stream *xdr,
                 struct nlm_cookie *cookie)
{
    u32 length;
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        goto out_overflow;
    length = be32_to_cpup(p++);
    /* apparently HPUX can return empty cookies */
    if (length == 0)
        goto out_hpux;
    if (length > NLM_MAXCOOKIELEN)
        goto out_size;
    p = xdr_inline_decode(xdr, length);
    if (unlikely(p == NULL))
        goto out_overflow;
    cookie->len = length;
    memcpy(cookie->data, p, length);
    return 0;
out_hpux:
    cookie->len = 4;
    memset(cookie->data, 0, 4);
    return 0;
out_size:
    dprintk("NFS: returned cookie was too long: %u\n", length);
    return -EIO;
out_overflow:
    print_overflow_msg(__func__, xdr);
    return -EIO;
}

/*
 *  netobj fh;
 */
static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
{
    BUG_ON(fh->size > NFS3_FHSIZE);
    encode_netobj(xdr, (u8 *)&fh->data, fh->size);
}

/*
 *  enum nlm4_stats {
 *      NLM4_GRANTED = 0,
 *      NLM4_DENIED = 1,
 *      NLM4_DENIED_NOLOCKS = 2,
 *      NLM4_BLOCKED = 3,
 *      NLM4_DENIED_GRACE_PERIOD = 4,
 *      NLM4_DEADLCK = 5,
 *      NLM4_ROFS = 6,
 *      NLM4_STALE_FH = 7,
 *      NLM4_FBIG = 8,
 *      NLM4_FAILED = 9
 *  };
 *
 *  struct nlm4_stat {
 *      nlm4_stats stat;
 *  };
 *
 * NB: we don't swap bytes for the NLM status values.  The upper
 * layers deal directly with the status value in network byte
 * order.
 */
static void encode_nlm4_stat(struct xdr_stream *xdr,
                 const __be32 stat)
{
    __be32 *p;

    BUG_ON(be32_to_cpu(stat) > NLM_FAILED);
    p = xdr_reserve_space(xdr, 4);
    *p = stat;
}

static int decode_nlm4_stat(struct xdr_stream *xdr, __be32 *stat)
{
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        goto out_overflow;
    if (unlikely(ntohl(*p) > ntohl(nlm4_failed)))
        goto out_bad_xdr;
    *stat = *p;
    return 0;
out_bad_xdr:
    dprintk("%s: server returned invalid nlm4_stats value: %u\n",
            __func__, be32_to_cpup(p));
    return -EIO;
out_overflow:
    print_overflow_msg(__func__, xdr);
    return -EIO;
}

/*
 *  struct nlm4_holder {
 *      bool    exclusive;
 *      int32   svid;
 *      netobj  oh;
 *      uint64  l_offset;
 *      uint64  l_len;
 *  };
 */
static void encode_nlm4_holder(struct xdr_stream *xdr,
                   const struct nlm_res *result)
{
    const struct nlm_lock *lock = &result->lock;
    u64 l_offset, l_len;
    __be32 *p;

    encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
    encode_int32(xdr, lock->svid);
    encode_netobj(xdr, lock->oh.data, lock->oh.len);

    p = xdr_reserve_space(xdr, 4 + 4);
    nlm4_compute_offsets(lock, &l_offset, &l_len);
    p = xdr_encode_hyper(p, l_offset);
    xdr_encode_hyper(p, l_len);
}

static int decode_nlm4_holder(struct xdr_stream *xdr, struct nlm_res *result)
{
    struct nlm_lock *lock = &result->lock;
    struct file_lock *fl = &lock->fl;
    u64 l_offset, l_len;
    u32 exclusive;
    int error;
    __be32 *p;
    s32 end;

    memset(lock, 0, sizeof(*lock));
    locks_init_lock(fl);

    p = xdr_inline_decode(xdr, 4 + 4);
    if (unlikely(p == NULL))
        goto out_overflow;
    exclusive = be32_to_cpup(p++);
    lock->svid = be32_to_cpup(p);
    fl->fl_pid = (pid_t)lock->svid;

    error = decode_netobj(xdr, &lock->oh);
    if (unlikely(error))
        goto out;

    p = xdr_inline_decode(xdr, 8 + 8);
    if (unlikely(p == NULL))
        goto out_overflow;

    fl->fl_flags = FL_POSIX;
    fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
    p = xdr_decode_hyper(p, &l_offset);
    xdr_decode_hyper(p, &l_len);
    end = l_offset + l_len - 1;

    fl->fl_start = (loff_t)l_offset;
    if (l_len == 0 || end < 0)
        fl->fl_end = OFFSET_MAX;
    else
        fl->fl_end = (loff_t)end;
    error = 0;
out:
    return error;
out_overflow:
    print_overflow_msg(__func__, xdr);
    return -EIO;
}

/*
 *  string caller_name<LM_MAXSTRLEN>;
 */
static void encode_caller_name(struct xdr_stream *xdr, const char *name)
{
    /* NB: client-side does not set lock->len */
    u32 length = strlen(name);
    __be32 *p;

    BUG_ON(length > NLM_MAXSTRLEN);
    p = xdr_reserve_space(xdr, 4 + length);
    xdr_encode_opaque(p, name, length);
}

/*
 *  struct nlm4_lock {
 *      string  caller_name<LM_MAXSTRLEN>;
 *      netobj  fh;
 *      netobj  oh;
 *      int32   svid;
 *      uint64  l_offset;
 *      uint64  l_len;
 *  };
 */
static void encode_nlm4_lock(struct xdr_stream *xdr,
                 const struct nlm_lock *lock)
{
    u64 l_offset, l_len;
    __be32 *p;

    encode_caller_name(xdr, lock->caller);
    encode_fh(xdr, &lock->fh);
    encode_netobj(xdr, lock->oh.data, lock->oh.len);

    p = xdr_reserve_space(xdr, 4 + 8 + 8);
    *p++ = cpu_to_be32(lock->svid);

    nlm4_compute_offsets(lock, &l_offset, &l_len);
    p = xdr_encode_hyper(p, l_offset);
    xdr_encode_hyper(p, l_len);
}


/*
 * NLMv4 XDR encode functions
 *
 * NLMv4 argument types are defined in Appendix II of RFC 1813:
 * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
 * "Protocols for Interworking: XNFS, Version 3W".
 */

/*
 *  struct nlm4_testargs {
 *      netobj cookie;
 *      bool exclusive;
 *      struct nlm4_lock alock;
 *  };
 */
static void nlm4_xdr_enc_testargs(struct rpc_rqst *req,
                  struct xdr_stream *xdr,
                  const struct nlm_args *args)
{
    const struct nlm_lock *lock = &args->lock;

    encode_cookie(xdr, &args->cookie);
    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
    encode_nlm4_lock(xdr, lock);
}

/*
 *  struct nlm4_lockargs {
 *      netobj cookie;
 *      bool block;
 *      bool exclusive;
 *      struct nlm4_lock alock;
 *      bool reclaim;
 *      int state;
 *  };
 */
static void nlm4_xdr_enc_lockargs(struct rpc_rqst *req,
                  struct xdr_stream *xdr,
                  const struct nlm_args *args)
{
    const struct nlm_lock *lock = &args->lock;

    encode_cookie(xdr, &args->cookie);
    encode_bool(xdr, args->block);
    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
    encode_nlm4_lock(xdr, lock);
    encode_bool(xdr, args->reclaim);
    encode_int32(xdr, args->state);
}

/*
 *  struct nlm4_cancargs {
 *      netobj cookie;
 *      bool block;
 *      bool exclusive;
 *      struct nlm4_lock alock;
 *  };
 */
static void nlm4_xdr_enc_cancargs(struct rpc_rqst *req,
                  struct xdr_stream *xdr,
                  const struct nlm_args *args)
{
    const struct nlm_lock *lock = &args->lock;

    encode_cookie(xdr, &args->cookie);
    encode_bool(xdr, args->block);
    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
    encode_nlm4_lock(xdr, lock);
}

/*
 *  struct nlm4_unlockargs {
 *      netobj cookie;
 *      struct nlm4_lock alock;
 *  };
 */
static void nlm4_xdr_enc_unlockargs(struct rpc_rqst *req,
                    struct xdr_stream *xdr,
                    const struct nlm_args *args)
{
    const struct nlm_lock *lock = &args->lock;

    encode_cookie(xdr, &args->cookie);
    encode_nlm4_lock(xdr, lock);
}

/*
 *  struct nlm4_res {
 *      netobj cookie;
 *      nlm4_stat stat;
 *  };
 */
static void nlm4_xdr_enc_res(struct rpc_rqst *req,
                 struct xdr_stream *xdr,
                 const struct nlm_res *result)
{
    encode_cookie(xdr, &result->cookie);
    encode_nlm4_stat(xdr, result->status);
}

/*
 *  union nlm4_testrply switch (nlm4_stats stat) {
 *  case NLM4_DENIED:
 *      struct nlm4_holder holder;
 *  default:
 *      void;
 *  };
 *
 *  struct nlm4_testres {
 *      netobj cookie;
 *      nlm4_testrply test_stat;
 *  };
 */
static void nlm4_xdr_enc_testres(struct rpc_rqst *req,
                 struct xdr_stream *xdr,
                 const struct nlm_res *result)
{
    encode_cookie(xdr, &result->cookie);
    encode_nlm4_stat(xdr, result->status);
    if (result->status == nlm_lck_denied)
        encode_nlm4_holder(xdr, result);
}


/*
 * NLMv4 XDR decode functions
 *
 * NLMv4 argument types are defined in Appendix II of RFC 1813:
 * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
 * "Protocols for Interworking: XNFS, Version 3W".
 */

/*
 *  union nlm4_testrply switch (nlm4_stats stat) {
 *  case NLM4_DENIED:
 *      struct nlm4_holder holder;
 *  default:
 *      void;
 *  };
 *
 *  struct nlm4_testres {
 *      netobj cookie;
 *      nlm4_testrply test_stat;
 *  };
 */
static int decode_nlm4_testrply(struct xdr_stream *xdr,
                struct nlm_res *result)
{
    int error;

    error = decode_nlm4_stat(xdr, &result->status);
    if (unlikely(error))
        goto out;
    if (result->status == nlm_lck_denied)
        error = decode_nlm4_holder(xdr, result);
out:
    return error;
}

static int nlm4_xdr_dec_testres(struct rpc_rqst *req,
                struct xdr_stream *xdr,
                struct nlm_res *result)
{
    int error;

    error = decode_cookie(xdr, &result->cookie);
    if (unlikely(error))
        goto out;
    error = decode_nlm4_testrply(xdr, result);
out:
    return error;
}

/*
 *  struct nlm4_res {
 *      netobj cookie;
 *      nlm4_stat stat;
 *  };
 */
static int nlm4_xdr_dec_res(struct rpc_rqst *req,
                struct xdr_stream *xdr,
                struct nlm_res *result)
{
    int error;

    error = decode_cookie(xdr, &result->cookie);
    if (unlikely(error))
        goto out;
    error = decode_nlm4_stat(xdr, &result->status);
out:
    return error;
}


/*
 * For NLM, a void procedure really returns nothing
 */
#define nlm4_xdr_dec_norep  NULL

#define PROC(proc, argtype, restype)                    \
[NLMPROC_##proc] = {                            \
    .p_proc      = NLMPROC_##proc,                  \
    .p_encode    = (kxdreproc_t)nlm4_xdr_enc_##argtype,     \
    .p_decode    = (kxdrdproc_t)nlm4_xdr_dec_##restype,     \
    .p_arglen    = NLM4_##argtype##_sz,             \
    .p_replen    = NLM4_##restype##_sz,             \
    .p_statidx   = NLMPROC_##proc,                  \
    .p_name      = #proc,                       \
    }

static struct rpc_procinfo  nlm4_procedures[] = {
    PROC(TEST,      testargs,   testres),
    PROC(LOCK,      lockargs,   res),
    PROC(CANCEL,        cancargs,   res),
    PROC(UNLOCK,        unlockargs, res),
    PROC(GRANTED,       testargs,   res),
    PROC(TEST_MSG,      testargs,   norep),
    PROC(LOCK_MSG,      lockargs,   norep),
    PROC(CANCEL_MSG,    cancargs,   norep),
    PROC(UNLOCK_MSG,    unlockargs, norep),
    PROC(GRANTED_MSG,   testargs,   norep),
    PROC(TEST_RES,      testres,    norep),
    PROC(LOCK_RES,      res,        norep),
    PROC(CANCEL_RES,    res,        norep),
    PROC(UNLOCK_RES,    res,        norep),
    PROC(GRANTED_RES,   res,        norep),
};

const struct rpc_version nlm_version4 = {
    .number     = 4,
    .nrprocs    = ARRAY_SIZE(nlm4_procedures),
    .procs      = nlm4_procedures,
};