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/*
 * include/linux/sunrpc/xdr.h
 *
 * Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
 */

#ifndef _SUNRPC_XDR_H_
#define _SUNRPC_XDR_H_

#ifdef __KERNEL__

#include <linux/uio.h>
#include <asm/byteorder.h>

/*
 * Buffer adjustment
 */
#define XDR_QUADLEN(l)          (((l) + 3) >> 2)

/*
 * Generic opaque `network object.' At the kernel level, this type
 * is used only by lockd.
 */
#define XDR_MAX_NETOBJ          1024
struct xdr_netobj {
        unsigned int            len;
        u8 *                    data;
};

/*
 * This is the generic XDR function. rqstp is either a rpc_rqst (client
 * side) or svc_rqst pointer (server side).
 * Encode functions always assume there's enough room in the buffer.
 */
typedef int     (*kxdrproc_t)(void *rqstp, u32 *data, void *obj);

/*
 * Basic structure for transmission/reception of a client XDR message.
 * Features a header (for a linear buffer containing RPC headers
 * and the data payload for short messages), and then an array of
 * pages.
 * The tail iovec allows you to append data after the page array. Its
 * main interest is for appending padding to the pages in order to
 * satisfy the int_32-alignment requirements in RFC1832.
 *
 * For the future, we might want to string several of these together
 * in a list if anybody wants to make use of NFSv4 COMPOUND
 * operations and/or has a need for scatter/gather involving pages.
 */
struct xdr_buf {
        struct iovec    head[1],        /* RPC header + non-page data */
                        tail[1];        /* Appended after page data */

        struct page **  pages;          /* Array of contiguous pages */
        unsigned int    page_base,      /* Start of page data */
                        page_len;       /* Length of page data */

        unsigned int    len;            /* Total length of data */

};

/*
 * pre-xdr'ed macros.
 */

#define xdr_zero        __constant_htonl(0)
#define xdr_one         __constant_htonl(1)
#define xdr_two         __constant_htonl(2)

#define rpc_success             __constant_htonl(RPC_SUCCESS)
#define rpc_prog_unavail        __constant_htonl(RPC_PROG_UNAVAIL)
#define rpc_prog_mismatch       __constant_htonl(RPC_PROG_MISMATCH)
#define rpc_proc_unavail        __constant_htonl(RPC_PROC_UNAVAIL)
#define rpc_garbage_args        __constant_htonl(RPC_GARBAGE_ARGS)
#define rpc_system_err          __constant_htonl(RPC_SYSTEM_ERR)

#define rpc_auth_ok             __constant_htonl(RPC_AUTH_OK)
#define rpc_autherr_badcred     __constant_htonl(RPC_AUTH_BADCRED)
#define rpc_autherr_rejectedcred __constant_htonl(RPC_AUTH_REJECTEDCRED)
#define rpc_autherr_badverf     __constant_htonl(RPC_AUTH_BADVERF)
#define rpc_autherr_rejectedverf __constant_htonl(RPC_AUTH_REJECTEDVERF)
#define rpc_autherr_tooweak     __constant_htonl(RPC_AUTH_TOOWEAK)
#define rpcsec_gsserr_credproblem       __constant_htonl(RPCSEC_GSS_CREDPROBLEM)
#define rpcsec_gsserr_ctxproblem        __constant_htonl(RPCSEC_GSS_CTXPROBLEM)
#define rpc_autherr_oldseqnum   __constant_htonl(101)

/*
 * Miscellaneous XDR helper functions
 */
u32 *   xdr_encode_array(u32 *p, const char *s, unsigned int len);
u32 *   xdr_encode_string(u32 *p, const char *s);
u32 *   xdr_decode_string(u32 *p, char **sp, int *lenp, int maxlen);
u32 *   xdr_decode_string_inplace(u32 *p, char **sp, int *lenp, int maxlen);
u32 *   xdr_encode_netobj(u32 *p, const struct xdr_netobj *);
u32 *   xdr_decode_netobj(u32 *p, struct xdr_netobj *);
u32 *   xdr_decode_netobj_fixed(u32 *p, void *obj, unsigned int len);

void    xdr_encode_pages(struct xdr_buf *, struct page **, unsigned int,
                         unsigned int);
void    xdr_inline_pages(struct xdr_buf *, unsigned int,
                         struct page **, unsigned int, unsigned int);

/*
 * Decode 64bit quantities (NFSv3 support)
 */
static inline u32 *
xdr_encode_hyper(u32 *p, __u64 val)
{
        *p++ = htonl(val >> 32);
        *p++ = htonl(val & 0xFFFFFFFF);
        return p;
}

static inline u32 *
xdr_decode_hyper(u32 *p, __u64 *valp)
{
        *valp  = ((__u64) ntohl(*p++)) << 32;
        *valp |= ntohl(*p++);
        return p;
}

/*
 * Adjust iovec to reflect end of xdr'ed data (RPC client XDR)
 */
static inline int
xdr_adjust_iovec(struct iovec *iov, u32 *p)
{
        return iov->iov_len = ((u8 *) p - (u8 *) iov->iov_base);
}

void xdr_shift_iovec(struct iovec *, int, size_t);

/*
 * Maximum number of iov's we use.
 */
#define MAX_IOVEC       (12)

/*
 * XDR buffer helper functions
 */
extern int xdr_kmap(struct iovec *, struct xdr_buf *, size_t);
extern void xdr_kunmap(struct xdr_buf *, size_t);
extern void xdr_shift_buf(struct xdr_buf *, size_t);

/*
 * Helper structure for copying from an sk_buff.
 */
typedef struct {
        struct sk_buff  *skb;
        unsigned int    offset;
        size_t          count;
        unsigned int    csum;
} skb_reader_t;

typedef size_t (*skb_read_actor_t)(skb_reader_t *desc, void *to, size_t len);

extern void xdr_partial_copy_from_skb(struct xdr_buf *, unsigned int,
                skb_reader_t *, skb_read_actor_t);

struct socket;
struct sockaddr;
extern int xdr_sendpages(struct socket *, struct sockaddr *, int,
                struct xdr_buf *, unsigned int, int);

/*
 * Provide some simple tools for XDR buffer overflow-checking etc.
 */
struct xdr_stream {
        uint32_t *p;            /* start of available buffer */
        struct xdr_buf *buf;    /* XDR buffer to read/write */

        uint32_t *end;          /* end of available buffer space */
        struct iovec *iov;      /* pointer to the current iovec */
};

/*
 * Initialize an xdr_stream for encoding data.
 *
 * Note: at the moment the RPC client only passes the length of our
 *       scratch buffer in the xdr_buf's header iovec. Previously this
 *       meant we needed to call xdr_adjust_iovec() after encoding the
 *       data. With the new scheme, the xdr_stream manages the details
 *       of the buffer length, and takes care of adjusting the iovec
 *       length for us.
 */
static inline void
xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p)
{
        struct iovec *iov = buf->head;

        xdr->buf = buf;
        xdr->iov = iov;
        xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
        buf->len = iov->iov_len = (char *)p - (char *)iov->iov_base;
        xdr->p = p;
}

/*
 * Check that we have enough buffer space to encode 'nbytes' more
 * bytes of data. If so, update the total xdr_buf length, and
 * adjust the length of the current iovec.
 */
static inline uint32_t *
xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
{
        uint32_t *p = xdr->p;
        uint32_t *q;

        /* align nbytes on the next 32-bit boundary */
        nbytes += 3;
        nbytes &= ~3;
        q = p + (nbytes >> 2);
        if (unlikely(q > xdr->end || q < p))
                return NULL;
        xdr->p = q;
        xdr->iov->iov_len += nbytes;
        xdr->buf->len += nbytes;
        return p;
}

extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
                unsigned int base, unsigned int len);
extern void xdr_read_pages(struct xdr_stream *xdr, unsigned int len);

/*
 * Initialize an xdr_stream for decoding data.
 */
static inline void
xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p)
{
        struct iovec *iov = buf->head;
        xdr->buf = buf;
        xdr->iov = iov;
        xdr->p = p;
        xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
}

/*
 * Check if the input buffer is long enough to enable us to decode
 * 'nbytes' more bytes of data starting at the current position.
 * If so return the current pointer, then update the current
 * position.
 */
static inline uint32_t *
xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
        uint32_t *p = xdr->p;
        uint32_t *q = p + XDR_QUADLEN(nbytes);

        if (unlikely(q > xdr->end || q < p))
                return NULL;
        xdr->p = q;
        return p;
}

#endif /* __KERNEL__ */

#endif /* _SUNRPC_XDR_H_ */