[GitHub/mt8127/android_kernel_alcatel_ttab.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/gfp.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>
fb286bb2 HX	10	#include <linux/netdevice.h>
5a0e3ad6	11	#include <linux/gfp.h>
fb286bb2	12	#include <linux/skbuff.h>
094bb20b CL	13	#include <linux/types.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/udp.h>
	16	#include <linux/sunrpc/xdr.h>
	17
	18
	19	/**
9d292316	20	* xdr_skb_read_bits - copy some data bits from skb to internal buffer
094bb20b CL	21	* @desc: sk_buff copy helper
	22	* @to: copy destination
	23	* @len: number of bytes to copy
	24	*
	25	* Possibly called several times to iterate over an sk_buff and copy
	26	* data out of it.
	27	*/
dd456471	28	size_t xdr_skb_read_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b CL	29	{
	30	if (len > desc->count)
	31	len = desc->count;
9d292316	32	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
094bb20b CL	33	return 0;
	34	desc->count -= len;
	35	desc->offset += len;
	36	return len;
	37	}
12444809	38	EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
094bb20b CL	39
094bb20b CL	40	/**
9d292316	41	* xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
094bb20b CL	42	* @desc: sk_buff copy helper
	43	* @to: copy destination
	44	* @len: number of bytes to copy
	45	*
	46	* Same as skb_read_bits, but calculate a checksum at the same time.
	47	*/
dd456471	48	static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b	49	{
5f92a738 AV	50	unsigned int pos;
5f92a738 AV	51	__wsum csum2;
094bb20b CL	52
	53	if (len > desc->count)
	54	len = desc->count;
	55	pos = desc->offset;
	56	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
	57	desc->csum = csum_block_add(desc->csum, csum2, pos);
	58	desc->count -= len;
	59	desc->offset += len;
	60	return len;
	61	}
	62
	63	/**
	64	* xdr_partial_copy_from_skb - copy data out of an skb
	65	* @xdr: target XDR buffer
	66	* @base: starting offset
	67	* @desc: sk_buff copy helper
	68	* @copy_actor: virtual method for copying data
	69	*
	70	*/
dd456471	71	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	72	{
	73	struct page **ppage = xdr->pages;
	74	unsigned int len, pglen = xdr->page_len;
	75	ssize_t copied = 0;
322e2efe	76	size_t ret;
094bb20b CL	77
	78	len = xdr->head[0].iov_len;
	79	if (base < len) {
	80	len -= base;
	81	ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
	82	copied += ret;
	83	if (ret != len \|\| !desc->count)
	84	goto out;
	85	base = 0;
	86	} else
	87	base -= len;
	88
	89	if (unlikely(pglen == 0))
	90	goto copy_tail;
	91	if (unlikely(base >= pglen)) {
	92	base -= pglen;
	93	goto copy_tail;
	94	}
	95	if (base \|\| xdr->page_base) {
	96	pglen -= base;
	97	base += xdr->page_base;
	98	ppage += base >> PAGE_CACHE_SHIFT;
	99	base &= ~PAGE_CACHE_MASK;
	100	}
	101	do {
	102	char *kaddr;
	103
	104	/* ACL likes to be lazy in allocating pages - ACLs
	105	* are small by default but can get huge. */
	106	if (unlikely(*ppage == NULL)) {
	107	*ppage = alloc_page(GFP_ATOMIC);
	108	if (unlikely(*ppage == NULL)) {
	109	if (copied == 0)
	110	copied = -ENOMEM;
	111	goto out;
	112	}
	113	}
	114
	115	len = PAGE_CACHE_SIZE;
	116	kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
	117	if (base) {
	118	len -= base;
	119	if (pglen < len)
	120	len = pglen;
	121	ret = copy_actor(desc, kaddr + base, len);
	122	base = 0;
	123	} else {
	124	if (pglen < len)
	125	len = pglen;
	126	ret = copy_actor(desc, kaddr, len);
	127	}
	128	flush_dcache_page(*ppage);
	129	kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
	130	copied += ret;
	131	if (ret != len \|\| !desc->count)
	132	goto out;
	133	ppage++;
	134	} while ((pglen -= len) != 0);
	135	copy_tail:
	136	len = xdr->tail[0].iov_len;
	137	if (base < len)
	138	copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
	139	out:
	140	return copied;
141	}
12444809	142	EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
094bb20b CL	143
	144	/**
	145	* csum_partial_copy_to_xdr - checksum and copy data
	146	* @xdr: target XDR buffer
	147	* @skb: source skb
	148	*
	149	* We have set things up such that we perform the checksum of the UDP
	150	* packet in parallel with the copies into the RPC client iovec. -DaveM
	151	*/
	152	int csum_partial_copy_to_xdr(struct xdr_buf xdr, struct sk_buff skb)
	153	{
dd456471	154	struct xdr_skb_reader desc;
094bb20b CL	155
	156	desc.skb = skb;
	157	desc.offset = sizeof(struct udphdr);
	158	desc.count = skb->len - desc.offset;
	159
60476372	160	if (skb_csum_unnecessary(skb))
094bb20b CL	161	goto no_checksum;
	162
	163	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
9d292316	164	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
094bb20b CL	165	return -1;
094bb20b CL	166	if (desc.offset != skb->len) {
5f92a738	167	__wsum csum2;
094bb20b CL	168	csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
	169	desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
	170	}
	171	if (desc.count)
	172	return -1;
d3bc23e7	173	if (csum_fold(desc.csum))
094bb20b	174	return -1;
84fa7933	175	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
fb286bb2	176	netdev_rx_csum_fault(skb->dev);
094bb20b CL	177	return 0;
094bb20b CL	178	no_checksum:
9d292316	179	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
094bb20b CL	180	return -1;
	181	if (desc.count)
	182	return -1;
	183	return 0;
	184	}
12444809	185	EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);