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root/fs/nfs/callback_xdr.c

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DEFINITIONS

This source file includes following definitions.
  1. nfs4_callback_null
  2. nfs4_decode_void
  3. nfs4_encode_void
  4. read_buf
  5. decode_string
  6. decode_fh
  7. decode_bitmap
  8. decode_stateid
  9. decode_compound_hdr_arg
  10. decode_op_hdr
  11. decode_getattr_args
  12. decode_recall_args
  13. encode_string
  14. encode_attr_bitmap
  15. encode_attr_change
  16. encode_attr_size
  17. encode_attr_time
  18. encode_attr_ctime
  19. encode_attr_mtime
  20. encode_compound_hdr_res
  21. encode_op_hdr
  22. encode_getattr_res
  23. process_op
  24. nfs4_callback_compound

/*
 * linux/fs/nfs/callback_xdr.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback encode/decode procedures
 */
#include <linux/kernel.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include "nfs4_fs.h"
#include "callback.h"

#define CB_OP_TAGLEN_MAXSZ      (512)
#define CB_OP_HDR_RES_MAXSZ     (2 + CB_OP_TAGLEN_MAXSZ)
#define CB_OP_GETATTR_BITMAP_MAXSZ      (4)
#define CB_OP_GETATTR_RES_MAXSZ (CB_OP_HDR_RES_MAXSZ + \
                                CB_OP_GETATTR_BITMAP_MAXSZ + \
                                2 + 2 + 3 + 3)
#define CB_OP_RECALL_RES_MAXSZ  (CB_OP_HDR_RES_MAXSZ)

#define NFSDBG_FACILITY NFSDBG_CALLBACK

typedef __be32 (*callback_process_op_t)(void *, void *);
typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);


struct callback_op {
        callback_process_op_t process_op;
        callback_decode_arg_t decode_args;
        callback_encode_res_t encode_res;
        long res_maxsize;
};

static struct callback_op callback_ops[];

static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
        return htonl(NFS4_OK);
}

static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
        return xdr_argsize_check(rqstp, p);
}

static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
        return xdr_ressize_check(rqstp, p);
}

static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, nbytes);
        if (unlikely(p == NULL))
                printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
        return p;
}

static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
{
        __be32 *p;

        p = read_buf(xdr, 4);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        *len = ntohl(*p);

        if (*len != 0) {
                p = read_buf(xdr, *len);
                if (unlikely(p == NULL))
                        return htonl(NFS4ERR_RESOURCE);
                *str = (const char *)p;
        } else
                *str = NULL;

        return 0;
}

static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
{
        __be32 *p;

        p = read_buf(xdr, 4);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        fh->size = ntohl(*p);
        if (fh->size > NFS4_FHSIZE)
                return htonl(NFS4ERR_BADHANDLE);
        p = read_buf(xdr, fh->size);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        memcpy(&fh->data[0], p, fh->size);
        memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
        return 0;
}

static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
{
        __be32 *p;
        unsigned int attrlen;

        p = read_buf(xdr, 4);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        attrlen = ntohl(*p);
        p = read_buf(xdr, attrlen << 2);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        if (likely(attrlen > 0))
                bitmap[0] = ntohl(*p++);
        if (attrlen > 1)
                bitmap[1] = ntohl(*p);
        return 0;
}

static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
{
        __be32 *p;

        p = read_buf(xdr, 16);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        memcpy(stateid->data, p, 16);
        return 0;
}

static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
{
        __be32 *p;
        unsigned int minor_version;
        __be32 status;

        status = decode_string(xdr, &hdr->taglen, &hdr->tag);
        if (unlikely(status != 0))
                return status;
        /* We do not like overly long tags! */
        if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
                printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
                                __func__, hdr->taglen);
                return htonl(NFS4ERR_RESOURCE);
        }
        p = read_buf(xdr, 12);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        minor_version = ntohl(*p++);
        /* Check minor version is zero. */
        if (minor_version != 0) {
                printk(KERN_WARNING "%s: NFSv4 server callback with illegal minor version %u!\n",
                                __func__, minor_version);
                return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
        }
        hdr->callback_ident = ntohl(*p++);
        hdr->nops = ntohl(*p);
        return 0;
}

static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
{
        __be32 *p;
        p = read_buf(xdr, 4);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        *op = ntohl(*p);
        return 0;
}

static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
{
        __be32 status;

        status = decode_fh(xdr, &args->fh);
        if (unlikely(status != 0))
                goto out;
        args->addr = svc_addr(rqstp);
        status = decode_bitmap(xdr, args->bitmap);
out:
        dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
        return status;
}

static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
{
        __be32 *p;
        __be32 status;

        args->addr = svc_addr(rqstp);
        status = decode_stateid(xdr, &args->stateid);
        if (unlikely(status != 0))
                goto out;
        p = read_buf(xdr, 4);
        if (unlikely(p == NULL)) {
                status = htonl(NFS4ERR_RESOURCE);
                goto out;
        }
        args->truncate = ntohl(*p);
        status = decode_fh(xdr, &args->fh);
out:
        dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
        return status;
}

static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, 4 + len);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        xdr_encode_opaque(p, str, len);
        return 0;
}

#define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
#define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
{
        __be32 bm[2];
        __be32 *p;

        bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
        bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
        if (bm[1] != 0) {
                p = xdr_reserve_space(xdr, 16);
                if (unlikely(p == NULL))
                        return htonl(NFS4ERR_RESOURCE);
                *p++ = htonl(2);
                *p++ = bm[0];
                *p++ = bm[1];
        } else if (bm[0] != 0) {
                p = xdr_reserve_space(xdr, 12);
                if (unlikely(p == NULL))
                        return htonl(NFS4ERR_RESOURCE);
                *p++ = htonl(1);
                *p++ = bm[0];
        } else {
                p = xdr_reserve_space(xdr, 8);
                if (unlikely(p == NULL))
                        return htonl(NFS4ERR_RESOURCE);
                *p++ = htonl(0);
        }
        *savep = p;
        return 0;
}

static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
{
        __be32 *p;

        if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
                return 0;
        p = xdr_reserve_space(xdr, 8);
        if (unlikely(!p))
                return htonl(NFS4ERR_RESOURCE);
        p = xdr_encode_hyper(p, change);
        return 0;
}

static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
{
        __be32 *p;

        if (!(bitmap[0] & FATTR4_WORD0_SIZE))
                return 0;
        p = xdr_reserve_space(xdr, 8);
        if (unlikely(!p))
                return htonl(NFS4ERR_RESOURCE);
        p = xdr_encode_hyper(p, size);
        return 0;
}

static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, 12);
        if (unlikely(!p))
                return htonl(NFS4ERR_RESOURCE);
        p = xdr_encode_hyper(p, time->tv_sec);
        *p = htonl(time->tv_nsec);
        return 0;
}

static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
{
        if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
                return 0;
        return encode_attr_time(xdr,time);
}

static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
{
        if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
                return 0;
        return encode_attr_time(xdr,time);
}

static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
{
        __be32 status;

        hdr->status = xdr_reserve_space(xdr, 4);
        if (unlikely(hdr->status == NULL))
                return htonl(NFS4ERR_RESOURCE);
        status = encode_string(xdr, hdr->taglen, hdr->tag);
        if (unlikely(status != 0))
                return status;
        hdr->nops = xdr_reserve_space(xdr, 4);
        if (unlikely(hdr->nops == NULL))
                return htonl(NFS4ERR_RESOURCE);
        return 0;
}

static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
{
        __be32 *p;
        
        p = xdr_reserve_space(xdr, 8);
        if (unlikely(p == NULL))
                return htonl(NFS4ERR_RESOURCE);
        *p++ = htonl(op);
        *p = res;
        return 0;
}

static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
{
        __be32 *savep = NULL;
        __be32 status = res->status;
        
        if (unlikely(status != 0))
                goto out;
        status = encode_attr_bitmap(xdr, res->bitmap, &savep);
        if (unlikely(status != 0))
                goto out;
        status = encode_attr_change(xdr, res->bitmap, res->change_attr);
        if (unlikely(status != 0))
                goto out;
        status = encode_attr_size(xdr, res->bitmap, res->size);
        if (unlikely(status != 0))
                goto out;
        status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
        if (unlikely(status != 0))
                goto out;
        status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
        *savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
out:
        dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
        return status;
}

static __be32 process_op(struct svc_rqst *rqstp,
                struct xdr_stream *xdr_in, void *argp,
                struct xdr_stream *xdr_out, void *resp)
{
        struct callback_op *op = &callback_ops[0];
        unsigned int op_nr = OP_CB_ILLEGAL;
        __be32 status = 0;
        long maxlen;
        __be32 res;

        dprintk("%s: start\n", __func__);
        status = decode_op_hdr(xdr_in, &op_nr);
        if (likely(status == 0)) {
                switch (op_nr) {
                        case OP_CB_GETATTR:
                        case OP_CB_RECALL:
                                op = &callback_ops[op_nr];
                                break;
                        default:
                                op_nr = OP_CB_ILLEGAL;
                                op = &callback_ops[0];
                                status = htonl(NFS4ERR_OP_ILLEGAL);
                }
        }

        maxlen = xdr_out->end - xdr_out->p;
        if (maxlen > 0 && maxlen < PAGE_SIZE) {
                if (likely(status == 0 && op->decode_args != NULL))
                        status = op->decode_args(rqstp, xdr_in, argp);
                if (likely(status == 0 && op->process_op != NULL))
                        status = op->process_op(argp, resp);
        } else
                status = htonl(NFS4ERR_RESOURCE);

        res = encode_op_hdr(xdr_out, op_nr, status);
        if (status == 0)
                status = res;
        if (op->encode_res != NULL && status == 0)
                status = op->encode_res(rqstp, xdr_out, resp);
        dprintk("%s: done, status = %d\n", __func__, ntohl(status));
        return status;
}

/*
 * Decode, process and encode a COMPOUND
 */
static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
{
        struct cb_compound_hdr_arg hdr_arg = { 0 };
        struct cb_compound_hdr_res hdr_res = { NULL };
        struct xdr_stream xdr_in, xdr_out;
        __be32 *p;
        __be32 status;
        unsigned int nops = 0;

        dprintk("%s: start\n", __func__);

        xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);

        p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
        xdr_init_encode(&xdr_out, &rqstp->rq_res, p);

        status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
        if (status == __constant_htonl(NFS4ERR_RESOURCE))
                return rpc_garbage_args;

        hdr_res.taglen = hdr_arg.taglen;
        hdr_res.tag = hdr_arg.tag;
        if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
                return rpc_system_err;

        while (status == 0 && nops != hdr_arg.nops) {
                status = process_op(rqstp, &xdr_in, argp, &xdr_out, resp);
                nops++;
        }

        *hdr_res.status = status;
        *hdr_res.nops = htonl(nops);
        dprintk("%s: done, status = %u\n", __func__, ntohl(status));
        return rpc_success;
}

/*
 * Define NFS4 callback COMPOUND ops.
 */
static struct callback_op callback_ops[] = {
        [0] = {
                .res_maxsize = CB_OP_HDR_RES_MAXSZ,
        },
        [OP_CB_GETATTR] = {
                .process_op = (callback_process_op_t)nfs4_callback_getattr,
                .decode_args = (callback_decode_arg_t)decode_getattr_args,
                .encode_res = (callback_encode_res_t)encode_getattr_res,
                .res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
        },
        [OP_CB_RECALL] = {
                .process_op = (callback_process_op_t)nfs4_callback_recall,
                .decode_args = (callback_decode_arg_t)decode_recall_args,
                .res_maxsize = CB_OP_RECALL_RES_MAXSZ,
        }
};

/*
 * Define NFS4 callback procedures
 */
static struct svc_procedure nfs4_callback_procedures1[] = {
        [CB_NULL] = {
                .pc_func = nfs4_callback_null,
                .pc_decode = (kxdrproc_t)nfs4_decode_void,
                .pc_encode = (kxdrproc_t)nfs4_encode_void,
                .pc_xdrressize = 1,
        },
        [CB_COMPOUND] = {
                .pc_func = nfs4_callback_compound,
                .pc_encode = (kxdrproc_t)nfs4_encode_void,
                .pc_argsize = 256,
                .pc_ressize = 256,
                .pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
        }
};

struct svc_version nfs4_callback_version1 = {
        .vs_vers = 1,
        .vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
        .vs_proc = nfs4_callback_procedures1,
        .vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
        .vs_dispatch = NULL,
};


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