path: root/net/sunrpc/xdr.c

/*
 * linux/net/sunrpc/xdr.c
 *
 * Generic XDR support.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/errno.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/msg_prot.h>

/*
 * XDR functions for basic NFS types
 */
__be32 *
xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
{
	unsigned int	quadlen = XDR_QUADLEN(obj->len);

	p[quadlen] = 0;		/* zero trailing bytes */
	*p++ = htonl(obj->len);
	memcpy(p, obj->data, obj->len);
	return p + XDR_QUADLEN(obj->len);
}

__be32 *
xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
{
	unsigned int	len;

	if ((len = ntohl(*p++)) > XDR_MAX_NETOBJ)
		return NULL;
	obj->len  = len;
	obj->data = (u8 *) p;
	return p + XDR_QUADLEN(len);
}

/**
 * xdr_encode_opaque_fixed - Encode fixed length opaque data
 * @p: pointer to current position in XDR buffer.
 * @ptr: pointer to data to encode (or NULL)
 * @nbytes: size of data.
 *
 * Copy the array of data of length nbytes at ptr to the XDR buffer
 * at position p, then align to the next 32-bit boundary by padding
 * with zero bytes (see RFC1832).
 * Note: if ptr is NULL, only the padding is performed.
 *
 * Returns the updated current XDR buffer position
 *
 */
__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
{
	if (likely(nbytes != 0)) {
		unsigned int quadlen = XDR_QUADLEN(nbytes);
		unsigned int padding = (quadlen << 2) - nbytes;

		if (ptr != NULL)
			memcpy(p, ptr, nbytes);
		if (padding != 0)
			memset((char *)p + nbytes, 0, padding);
		p += quadlen;
	}
	return p;
}
EXPORT_SYMBOL(xdr_encode_opaque_fixed);

/**
 * xdr_encode_opaque - Encode variable length opaque data
 * @p: pointer to current position in XDR buffer.
 * @ptr: pointer to data to encode (or NULL)
 * @nbytes: size of data.
 *
 * Returns the updated current XDR buffer position
 */
__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
{
	*p++ = htonl(nbytes);
	return xdr_encode_opaque_fixed(p, ptr, nbytes);
}
EXPORT_SYMBOL(xdr_encode_opaque);

__be32 *
xdr_encode_string(__be32 *p, const char *string)
{
	return xdr_encode_array(p, string, strlen(string));
}

__be32 *
xdr_decode_string_inplace(__be32 *p, char **sp, int *lenp, int maxlen)
{
	unsigned int	len;

	if ((len = ntohl(*p++)) > maxlen)
		return NULL;
	*lenp = len;
	*sp = (char *) p;
	return p + XDR_QUADLEN(len);
}

void
xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base,
		 unsigned int len)
{
	struct kvec *tail = xdr->tail;
	u32 *p;

	xdr->pages = pages;
	xdr->page_base = base;
	xdr->page_len = len;

	p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len);
	tail->iov_base = p;
	tail->iov_len = 0;

	if (len & 3) {
		unsigned int pad = 4 - (len & 3);

		*p = 0;
		tail->iov_base = (char *)p + (len & 3);
		tail->iov_len  = pad;
		len += pad;
	}
	xdr->buflen += len;
	xdr->len += len;
}

void
xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
		 struct page **pages, unsigned int base, unsigned int len)
{
	struct </