[mirror_ubuntu-bionic-kernel.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>
#include <linux/export.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_SHIFT;
		base &= ~PAGE_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_SIZE;
		kaddr = kmap_atomic(*ppage);
		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);
		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 = 0;
	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) &&
	    !skb->csum_complete_sw)
		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>
bc3b2d7f	17	#include <linux/export.h>
094bb20b CL	18
	19
	20	/**
9d292316	21	* xdr_skb_read_bits - copy some data bits from skb to internal buffer
094bb20b CL	22	* @desc: sk_buff copy helper
	23	* @to: copy destination
	24	* @len: number of bytes to copy
	25	*
	26	* Possibly called several times to iterate over an sk_buff and copy
	27	* data out of it.
	28	*/
dd456471	29	size_t xdr_skb_read_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b CL	30	{
	31	if (len > desc->count)
	32	len = desc->count;
9d292316	33	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
094bb20b CL	34	return 0;
	35	desc->count -= len;
	36	desc->offset += len;
	37	return len;
	38	}
12444809	39	EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
094bb20b CL	40
094bb20b CL	41	/**
9d292316	42	* xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
094bb20b CL	43	* @desc: sk_buff copy helper
	44	* @to: copy destination
	45	* @len: number of bytes to copy
	46	*
	47	* Same as skb_read_bits, but calculate a checksum at the same time.
	48	*/
dd456471	49	static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader desc, void to, size_t len)
094bb20b	50	{
5f92a738 AV	51	unsigned int pos;
5f92a738 AV	52	__wsum csum2;
094bb20b CL	53
	54	if (len > desc->count)
	55	len = desc->count;
	56	pos = desc->offset;
	57	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
	58	desc->csum = csum_block_add(desc->csum, csum2, pos);
	59	desc->count -= len;
	60	desc->offset += len;
	61	return len;
	62	}
	63
	64	/**
	65	* xdr_partial_copy_from_skb - copy data out of an skb
	66	* @xdr: target XDR buffer
	67	* @base: starting offset
	68	* @desc: sk_buff copy helper
	69	* @copy_actor: virtual method for copying data
	70	*
	71	*/
dd456471	72	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	73	{
	74	struct page **ppage = xdr->pages;
	75	unsigned int len, pglen = xdr->page_len;
	76	ssize_t copied = 0;
322e2efe	77	size_t ret;
094bb20b CL	78
	79	len = xdr->head[0].iov_len;
	80	if (base < len) {
	81	len -= base;
	82	ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
	83	copied += ret;
	84	if (ret != len \|\| !desc->count)
	85	goto out;
	86	base = 0;
	87	} else
	88	base -= len;
	89
	90	if (unlikely(pglen == 0))
	91	goto copy_tail;
	92	if (unlikely(base >= pglen)) {
	93	base -= pglen;
	94	goto copy_tail;
	95	}
	96	if (base \|\| xdr->page_base) {
	97	pglen -= base;
	98	base += xdr->page_base;
09cbfeaf KS	99	ppage += base >> PAGE_SHIFT;
09cbfeaf KS	100	base &= ~PAGE_MASK;
094bb20b CL	101	}
	102	do {
	103	char *kaddr;
	104
	105	/* ACL likes to be lazy in allocating pages - ACLs
	106	* are small by default but can get huge. */
	107	if (unlikely(*ppage == NULL)) {
	108	*ppage = alloc_page(GFP_ATOMIC);
	109	if (unlikely(*ppage == NULL)) {
	110	if (copied == 0)
	111	copied = -ENOMEM;
	112	goto out;
	113	}
	114	}
	115
09cbfeaf	116	len = PAGE_SIZE;
b8541786	117	kaddr = kmap_atomic(*ppage);
094bb20b CL	118	if (base) {
	119	len -= base;
	120	if (pglen < len)
	121	len = pglen;
	122	ret = copy_actor(desc, kaddr + base, len);
	123	base = 0;
	124	} else {
	125	if (pglen < len)
	126	len = pglen;
	127	ret = copy_actor(desc, kaddr, len);
	128	}
	129	flush_dcache_page(*ppage);
b8541786	130	kunmap_atomic(kaddr);
094bb20b CL	131	copied += ret;
	132	if (ret != len \|\| !desc->count)
	133	goto out;
	134	ppage++;
	135	} while ((pglen -= len) != 0);
	136	copy_tail:
	137	len = xdr->tail[0].iov_len;
	138	if (base < len)
	139	copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
	140	out:
	141	return copied;
	142	}
12444809	143	EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
094bb20b CL	144
	145	/**
	146	* csum_partial_copy_to_xdr - checksum and copy data
	147	* @xdr: target XDR buffer
	148	* @skb: source skb
	149	*
	150	* We have set things up such that we perform the checksum of the UDP
	151	* packet in parallel with the copies into the RPC client iovec. -DaveM
	152	*/
	153	int csum_partial_copy_to_xdr(struct xdr_buf xdr, struct sk_buff skb)
	154	{
dd456471	155	struct xdr_skb_reader desc;
094bb20b CL	156
094bb20b CL	157	desc.skb = skb;
1da8c681	158	desc.offset = 0;
094bb20b CL	159	desc.count = skb->len - desc.offset;
094bb20b CL	160
60476372	161	if (skb_csum_unnecessary(skb))
094bb20b CL	162	goto no_checksum;
	163
	164	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
9d292316	165	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
094bb20b CL	166	return -1;
094bb20b CL	167	if (desc.offset != skb->len) {
5f92a738	168	__wsum csum2;
094bb20b CL	169	csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
	170	desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
	171	}
	172	if (desc.count)
	173	return -1;
d3bc23e7	174	if (csum_fold(desc.csum))
094bb20b	175	return -1;
7e3cead5 TH	176	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
7e3cead5 TH	177	!skb->csum_complete_sw)
fb286bb2	178	netdev_rx_csum_fault(skb->dev);
094bb20b CL	179	return 0;
094bb20b CL	180	no_checksum:
9d292316	181	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
094bb20b CL	182	return -1;
	183	if (desc.count)
	184	return -1;
	185	return 0;
	186	}
12444809	187	EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);