[linux-2.6-block.git] / net / sunrpc / socklib.c

/*
 * linux/net/sunrpc/socklib.c
 *
 * Common socket helper routines for RPC client and server
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/compiler.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/udp.h>
#include <linux/sunrpc/xdr.h>


/**
 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
 * @desc: sk_buff copy helper
 * @to: copy destination
 * @len: number of bytes to copy
 *
 * Possibly called several times to iterate over an sk_buff and copy
 * data out of it.
 */
size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
{
	if (len > desc->count)
		len = desc->count;
	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
		return 0;
	desc->count -= len;
	desc->offset += len;
	return len;
}
EXPORT_SYMBOL_GPL(xdr_skb_read_bits);

/**
 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
 * @desc: sk_buff copy helper
 * @to: copy destination
 * @len: number of bytes to copy
 *
 * Same as skb_read_bits, but calculate a checksum at the same time.
 */
static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
{
	unsigned int pos;
	__wsum csum2;

	if (len > desc->count)
		len = desc->count;
	pos = desc->offset;
	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
	desc->csum = csum_block_add(desc->csum, csum2, pos);
	desc->count -= len;
	desc->offset += len;
	return len;
}

/**
 * xdr_partial_copy_from_skb - copy data out of an skb
 * @xdr: target XDR buffer
 * @base: starting offset
 * @desc: sk_buff copy helper
 * @copy_actor: virtual method for copying data
 *
 */
ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
{
	struct page	**ppage = xdr->pages;
	unsigned int	len, pglen = xdr->page_len;
	ssize_t		copied = 0;
	size_t		ret;

	len = xdr->head[0].iov_len;
	if (base < len) {
		len -= base;
		ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
		copied += ret;
		if (ret != len || !desc->count)
			goto out;
		base = 0;
	} else
		base -= len;

	if (unlikely(pglen == 0))
		goto copy_tail;
	if (unlikely(base >= pglen)) {
		base -= pglen;
		goto copy_tail;
	}
	if (base || xdr->page_base) {
		pglen -= base;
		base += xdr->page_base;
		ppage += base >> PAGE_CACHE_SHIFT;
		base &= ~PAGE_CACHE_MASK;
	}
	do {
		char *kaddr;

		/* ACL likes to be lazy in allocating pages - ACLs
		 * are small by default but can get huge. */
		if (unlikely(*ppage == NULL)) {
			*ppage = alloc_page(GFP_ATOMIC);
			if (unlikely(*ppage == NULL)) {
				if (copied == 0)
					copied = -ENOMEM;
				goto out;
			}
		}

		len = PAGE_CACHE_SIZE;
		kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
		if (base) {
			len -= base;
			if (pglen < len)
				len = pglen;
			ret = copy_actor(desc, kaddr + base, len);
			base = 0;
		} else {
			if (pglen < len)
				len = pglen;
			ret = copy_actor(desc, kaddr, len);
		}
		flush_dcache_page(*ppage);
		kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
		copied += ret;
		if (ret != len || !desc->count)
			goto out;
		ppage++;
	} while ((pglen -= len) != 0);
copy_tail:
	len = xdr->tail[0].iov_len;
	if (base < len)
		copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
out:
	return copied;
}
EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);

/**
 * csum_partial_copy_to_xdr - checksum and copy data
 * @xdr: target XDR buffer
 * @skb: source skb
 *
 * We have set things up such that we perform the checksum of the UDP
 * packet in parallel with the copies into the RPC client iovec.  -DaveM
 */
int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
{
	struct xdr_skb_reader	desc;

	desc.skb = skb;
	desc.offset = sizeof(struct udphdr);
	desc.count = skb->len - desc.offset;

	if (skb_csum_unnecessary(skb))
		goto no_checksum;

	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
		return -1;
	if (desc.offset != skb->len) {
		__wsum csum2;
		csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
		desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
	}
	if (desc.count)
		return -1;
	if (csum_fold(desc.csum))
		return -1;
	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
		netdev_rx_csum_fault(skb->dev);
	return 0;
no_checksum:
	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
		return -1;
	if (desc.count)
		return -1;
	return 0;
}
EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);
Commit	Line	Data
094bb20b CL	1	/*
	2	* linux/net/sunrpc/socklib.c
	3	*
	4	* Common socket helper routines for RPC client and server
	5	*
	6	* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
	7	*/
	8
fb286bb2 HX	9	#include <linux/compiler.h>
	10	#include <linux/netdevice.h>
	11	#include <linux/skbuff.h>
094bb20b CL	12	#include <linux/types.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/udp.h>
	15	#include <linux/sunrpc/xdr.h>
	16
	17
	18	/**
9d292316	19	* xdr_skb_read_bits - copy some data bits from skb to internal buffer
094bb20b CL	20	* @desc: sk_buff copy helper
	21	* @to: copy destination
	22	* @len: number of bytes to copy
	23	*
	24	* Possibly called several times to iterate over an sk_buff and copy
	25	* data out of it.
	26	*/
dd456471	27	size_t xdr_skb_read_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b CL	28	{
	29	if (len > desc->count)
	30	len = desc->count;
9d292316	31	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
094bb20b CL	32	return 0;
	33	desc->count -= len;
	34	desc->offset += len;
	35	return len;
	36	}
12444809	37	EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
094bb20b CL	38
094bb20b CL	39	/**
9d292316	40	* xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
094bb20b CL	41	* @desc: sk_buff copy helper
	42	* @to: copy destination
	43	* @len: number of bytes to copy
	44	*
	45	* Same as skb_read_bits, but calculate a checksum at the same time.
	46	*/
dd456471	47	static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b	48	{
5f92a738 AV	49	unsigned int pos;
5f92a738 AV	50	__wsum csum2;
094bb20b CL	51
	52	if (len > desc->count)
	53	len = desc->count;
	54	pos = desc->offset;
	55	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
	56	desc->csum = csum_block_add(desc->csum, csum2, pos);
	57	desc->count -= len;
	58	desc->offset += len;
	59	return len;
	60	}
	61
	62	/**
	63	* xdr_partial_copy_from_skb - copy data out of an skb
	64	* @xdr: target XDR buffer
	65	* @base: starting offset
	66	* @desc: sk_buff copy helper
	67	* @copy_actor: virtual method for copying data
	68	*
	69	*/
dd456471	70	ssize_t xdr_partial_copy_from_skb(struct xdr_buf xdr, unsigned int base, struct xdr_skb_reader desc, xdr_skb_read_actor copy_actor)
094bb20b CL	71	{
	72	struct page **ppage = xdr->pages;
	73	unsigned int len, pglen = xdr->page_len;
	74	ssize_t copied = 0;
322e2efe	75	size_t ret;
094bb20b CL	76
	77	len = xdr->head[0].iov_len;
	78	if (base < len) {
	79	len -= base;
	80	ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
	81	copied += ret;
	82	if (ret != len \|\| !desc->count)
	83	goto out;
	84	base = 0;
	85	} else
	86	base -= len;
	87
	88	if (unlikely(pglen == 0))
	89	goto copy_tail;
	90	if (unlikely(base >= pglen)) {
	91	base -= pglen;
	92	goto copy_tail;
	93	}
	94	if (base \|\| xdr->page_base) {
	95	pglen -= base;
	96	base += xdr->page_base;
	97	ppage += base >> PAGE_CACHE_SHIFT;
	98	base &= ~PAGE_CACHE_MASK;
	99	}
	100	do {
	101	char *kaddr;
	102
	103	/* ACL likes to be lazy in allocating pages - ACLs
	104	* are small by default but can get huge. */
	105	if (unlikely(*ppage == NULL)) {
	106	*ppage = alloc_page(GFP_ATOMIC);
	107	if (unlikely(*ppage == NULL)) {
	108	if (copied == 0)
	109	copied = -ENOMEM;
	110	goto out;
	111	}
	112	}
	113
	114	len = PAGE_CACHE_SIZE;
	115	kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
	116	if (base) {
	117	len -= base;
	118	if (pglen < len)
	119	len = pglen;
	120	ret = copy_actor(desc, kaddr + base, len);
	121	base = 0;
	122	} else {
	123	if (pglen < len)
	124	len = pglen;
	125	ret = copy_actor(desc, kaddr, len);
	126	}
	127	flush_dcache_page(*ppage);
	128	kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
	129	copied += ret;
	130	if (ret != len \|\| !desc->count)
	131	goto out;
	132	ppage++;
	133	} while ((pglen -= len) != 0);
	134	copy_tail:
	135	len = xdr->tail[0].iov_len;
	136	if (base < len)
	137	copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
	138	out:
	139	return copied;
140	}
12444809	141	EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
094bb20b CL	142
	143	/**
	144	* csum_partial_copy_to_xdr - checksum and copy data
	145	* @xdr: target XDR buffer
	146	* @skb: source skb
	147	*
	148	* We have set things up such that we perform the checksum of the UDP
	149	* packet in parallel with the copies into the RPC client iovec. -DaveM
	150	*/
	151	int csum_partial_copy_to_xdr(struct xdr_buf xdr, struct sk_buff skb)
	152	{
dd456471	153	struct xdr_skb_reader desc;
094bb20b CL	154
	155	desc.skb = skb;
	156	desc.offset = sizeof(struct udphdr);
	157	desc.count = skb->len - desc.offset;
	158
60476372	159	if (skb_csum_unnecessary(skb))
094bb20b CL	160	goto no_checksum;
	161
	162	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
9d292316	163	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
094bb20b CL	164	return -1;
094bb20b CL	165	if (desc.offset != skb->len) {
5f92a738	166	__wsum csum2;
094bb20b CL	167	csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
	168	desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
	169	}
	170	if (desc.count)
	171	return -1;
d3bc23e7	172	if (csum_fold(desc.csum))
094bb20b	173	return -1;
84fa7933	174	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
fb286bb2	175	netdev_rx_csum_fault(skb->dev);
094bb20b CL	176	return 0;
094bb20b CL	177	no_checksum:
9d292316	178	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
094bb20b CL	179	return -1;
	180	if (desc.count)
	181	return -1;
	182	return 0;
	183	}
12444809	184	EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);