/*
 * linux/fs/lockd/clntxdr.c
 *
 * XDR functions to encode/decode NLM version 3 RPC arguments and results.
 * NLM version 3 is backwards compatible with NLM versions 1 and 2.
 *
 * 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

/*
 * Declare the space requirements for NLM arguments and replies as
 * number of 32bit-words
 */
#define NLM_cookie_sz           (1+(NLM_MAXCOOKIELEN>>2))
#define NLM_caller_sz           (1+(NLMCLNT_OHSIZE>>2))
#define NLM_owner_sz            (1+(NLMCLNT_OHSIZE>>2))
#define NLM_fhandle_sz          (1+(NFS2_FHSIZE>>2))
#define NLM_lock_sz             (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
#define NLM_holder_sz           (4+NLM_owner_sz)

#define NLM_testargs_sz         (NLM_cookie_sz+1+NLM_lock_sz)
#define NLM_lockargs_sz         (NLM_cookie_sz+4+NLM_lock_sz)
#define NLM_cancargs_sz         (NLM_cookie_sz+2+NLM_lock_sz)
#define NLM_unlockargs_sz       (NLM_cookie_sz+NLM_lock_sz)

#define NLM_testres_sz          (NLM_cookie_sz+1+NLM_holder_sz)
#define NLM_res_sz              (NLM_cookie_sz+1)
#define NLM_norep_sz            (0)


static s32 loff_t_to_s32(loff_t offset)
{
        s32 res;

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

static void nlm_compute_offsets(const struct nlm_lock *lock,
                                u32 *l_offset, u32 *l_len)
{
        const struct file_lock *fl = &lock->fl;

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

        *l_offset = loff_t_to_s32(fl->fl_start);
        if (fl->fl_end == OFFSET_MAX)
                *l_len = 0;
        else
                *l_len = loff_t_to_s32(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 NLMv3 basic data types
 *
 * Basic NLMv3 data types are not defined in an IETF standards
 * document.  X/Open has a description of these data types that
 * is useful.  See Chapter 10 of "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 != NFS2_FHSIZE);
        encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
}

/*
 *      enum nlm_stats {
 *              LCK_GRANTED = 0,
 *              LCK_DENIED = 1,
 *              LCK_DENIED_NOLOCKS = 2,
 *              LCK_BLOCKED = 3,
 *              LCK_DENIED_GRACE_PERIOD = 4
 *      };
 *
 *
 *      struct nlm_stat {
 *              nlm_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_nlm_stat(struct xdr_stream *xdr,
                            const __be32 stat)
{
        __be32 *p;

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

static int decode_nlm_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(nlm_lck_denied_grace_period)))
                goto out_enum;
        *stat = *p;
        return 0;
out_enum:
        dprintk("%s: server returned invalid nlm_stats value: %u\n",
                __func__, be32_to_cpup(p));
        return -EIO;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 *      struct nlm_holder {
 *              bool exclusive;
 *              int uppid;
 *              netobj oh;
 *              unsigned l_offset;
 *              unsigned l_len;
 *      };
 */
static void encode_nlm_holder(struct xdr_stream *xdr,
                              const struct nlm_res *result)
{
        const struct nlm_lock *lock = &result->lock;
        u32 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);
        nlm_compute_offsets(lock, &l_offset, &l_len);
        *p++ = cpu_to_be32(l_offset);
        *p   = cpu_to_be32(l_len);
}

static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
{
        struct nlm_lock *lock = &result->lock;
        struct file_lock *fl = &lock->fl;
        u32 exclusive, l_offset, l_len;
        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, 4 + 4);
        if (unlikely(p == NULL))
                goto out_overflow;

        fl->fl_flags = FL_POSIX;
        fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
        l_offset = be32_to_cpup(p++);
        l_len = be32_to_cpup(p);
        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 nlm_lock {
 *              string caller_name<LM_MAXSTRLEN>;
 *              netobj fh;
 *              netobj oh;
 *              int uppid;
 *              unsigned l_offset;
 *              unsigned l_len;
 *      };
 */
static void encode_nlm_lock(struct xdr_stream *xdr,
                            const struct nlm_lock *lock)
{
        u32 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 + 4 + 4);
        *p++ = cpu_to_be32(lock->svid);

        nlm_compute_offsets(lock, &l_offset, &l_len);
        *p++ = cpu_to_be32(l_offset);
        *p   = cpu_to_be32(l_len);
}


/*
 * NLMv3 XDR encode functions
 *
 * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 * "Protocols for Interworking: XNFS, Version 3W".
 */

/*
 *      struct nlm_testargs {
 *              netobj cookie;
 *              bool exclusive;
 *              struct nlm_lock alock;
 *      };
 */
static void nlm_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_nlm_lock(xdr, lock);
}

/*
 *      struct nlm_lockargs {
 *              netobj cookie;
 *              bool block;
 *              bool exclusive;
 *              struct nlm_lock alock;
 *              bool reclaim;
 *              int state;
 *      };
 */
static void nlm_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_nlm_lock(xdr, lock);
        encode_bool(xdr, args->reclaim);
        encode_int32(xdr, args->state);
}

/*
 *      struct nlm_cancargs {
 *              netobj cookie;
 *              bool block;
 *              bool exclusive;
 *              struct nlm_lock alock;
 *      };
 */
static void nlm_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_nlm_lock(xdr, lock);
}

/*
 *      struct nlm_unlockargs {
 *              netobj cookie;
 *              struct nlm_lock alock;
 *      };
 */
static void nlm_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_nlm_lock(xdr, lock);
}

/*
 *      struct nlm_res {
 *              netobj cookie;
 *              nlm_stat stat;
 *      };
 */
static void nlm_xdr_enc_res(struct rpc_rqst *req,
                            struct xdr_stream *xdr,
                            const struct nlm_res *result)
{
        encode_cookie(xdr, &result->cookie);
        encode_nlm_stat(xdr, result->status);
}

/*
 *      union nlm_testrply switch (nlm_stats stat) {
 *      case LCK_DENIED:
 *              struct nlm_holder holder;
 *      default:
 *              void;
 *      };
 *
 *      struct nlm_testres {
 *              netobj cookie;
 *              nlm_testrply test_stat;
 *      };
 */
static void encode_nlm_testrply(struct xdr_stream *xdr,
                                const struct nlm_res *result)
{
        if (result->status == nlm_lck_denied)
                encode_nlm_holder(xdr, result);
}

static void nlm_xdr_enc_testres(struct rpc_rqst *req,
                                struct xdr_stream *xdr,
                                const struct nlm_res *result)
{
        encode_cookie(xdr, &result->cookie);
        encode_nlm_stat(xdr, result->status);
        encode_nlm_testrply(xdr, result);
}


/*
 * NLMv3 XDR decode functions
 *
 * NLMv3 result types are defined in Chapter 10 of The Open Group's
 * "Protocols for Interworking: XNFS, Version 3W".
 */

/*
 *      union nlm_testrply switch (nlm_stats stat) {
 *      case LCK_DENIED:
 *              struct nlm_holder holder;
 *      default:
 *              void;
 *      };
 *
 *      struct nlm_testres {
 *              netobj cookie;
 *              nlm_testrply test_stat;
 *      };
 */
static int decode_nlm_testrply(struct xdr_stream *xdr,
                               struct nlm_res *result)
{
        int error;

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

static int nlm_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_nlm_testrply(xdr, result);
out:
        return error;
}

/*
 *      struct nlm_res {
 *              netobj cookie;
 *              nlm_stat stat;
 *      };
 */
static int nlm_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_nlm_stat(xdr, &result->status);
out:
        return error;
}


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

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

static struct rpc_procinfo      nlm_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),
};

static const struct rpc_version nlm_version1 = {
                .number         = 1,
                .nrprocs        = ARRAY_SIZE(nlm_procedures),
                .procs          = nlm_procedures,
};

static const struct rpc_version nlm_version3 = {
                .number         = 3,
                .nrprocs        = ARRAY_SIZE(nlm_procedures),
                .procs          = nlm_procedures,
};

static const struct rpc_version *nlm_versions[] = {
        [1] = &nlm_version1,
        [3] = &nlm_version3,
#ifdef CONFIG_LOCKD_V4
        [4] = &nlm_version4,
#endif
};

static struct rpc_stat          nlm_rpc_stats;

const struct rpc_program        nlm_program = {
                .name           = "lockd",
                .number         = NLM_PROGRAM,
                .nrvers         = ARRAY_SIZE(nlm_versions),
                .version        = nlm_versions,
                .stats          = &nlm_rpc_stats,
};