2 * linux/net/sunrpc/socklib.c
4 * Common socket helper routines for RPC client and server
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
9 #include <linux/types.h>
10 #include <linux/pagemap.h>
11 #include <linux/udp.h>
12 #include <linux/sunrpc/xdr.h>
16 * skb_read_bits - copy some data bits from skb to internal buffer
17 * @desc: sk_buff copy helper
18 * @to: copy destination
19 * @len: number of bytes to copy
21 * Possibly called several times to iterate over an sk_buff and copy
24 static size_t skb_read_bits(skb_reader_t
*desc
, void *to
, size_t len
)
26 if (len
> desc
->count
)
28 if (skb_copy_bits(desc
->skb
, desc
->offset
, to
, len
))
36 * skb_read_and_csum_bits - copy and checksum from skb to buffer
37 * @desc: sk_buff copy helper
38 * @to: copy destination
39 * @len: number of bytes to copy
41 * Same as skb_read_bits, but calculate a checksum at the same time.
43 static size_t skb_read_and_csum_bits(skb_reader_t
*desc
, void *to
, size_t len
)
45 unsigned int csum2
, pos
;
47 if (len
> desc
->count
)
50 csum2
= skb_copy_and_csum_bits(desc
->skb
, pos
, to
, len
, 0);
51 desc
->csum
= csum_block_add(desc
->csum
, csum2
, pos
);
58 * xdr_partial_copy_from_skb - copy data out of an skb
59 * @xdr: target XDR buffer
60 * @base: starting offset
61 * @desc: sk_buff copy helper
62 * @copy_actor: virtual method for copying data
65 ssize_t
xdr_partial_copy_from_skb(struct xdr_buf
*xdr
, unsigned int base
, skb_reader_t
*desc
, skb_read_actor_t copy_actor
)
67 struct page
**ppage
= xdr
->pages
;
68 unsigned int len
, pglen
= xdr
->page_len
;
72 len
= xdr
->head
[0].iov_len
;
75 ret
= copy_actor(desc
, (char *)xdr
->head
[0].iov_base
+ base
, len
);
77 if (ret
!= len
|| !desc
->count
)
83 if (unlikely(pglen
== 0))
85 if (unlikely(base
>= pglen
)) {
89 if (base
|| xdr
->page_base
) {
91 base
+= xdr
->page_base
;
92 ppage
+= base
>> PAGE_CACHE_SHIFT
;
93 base
&= ~PAGE_CACHE_MASK
;
98 /* ACL likes to be lazy in allocating pages - ACLs
99 * are small by default but can get huge. */
100 if (unlikely(*ppage
== NULL
)) {
101 *ppage
= alloc_page(GFP_ATOMIC
);
102 if (unlikely(*ppage
== NULL
)) {
109 len
= PAGE_CACHE_SIZE
;
110 kaddr
= kmap_atomic(*ppage
, KM_SKB_SUNRPC_DATA
);
115 ret
= copy_actor(desc
, kaddr
+ base
, len
);
120 ret
= copy_actor(desc
, kaddr
, len
);
122 flush_dcache_page(*ppage
);
123 kunmap_atomic(kaddr
, KM_SKB_SUNRPC_DATA
);
125 if (ret
!= len
|| !desc
->count
)
128 } while ((pglen
-= len
) != 0);
130 len
= xdr
->tail
[0].iov_len
;
132 copied
+= copy_actor(desc
, (char *)xdr
->tail
[0].iov_base
+ base
, len
- base
);
138 * csum_partial_copy_to_xdr - checksum and copy data
139 * @xdr: target XDR buffer
142 * We have set things up such that we perform the checksum of the UDP
143 * packet in parallel with the copies into the RPC client iovec. -DaveM
145 int csum_partial_copy_to_xdr(struct xdr_buf
*xdr
, struct sk_buff
*skb
)
150 desc
.offset
= sizeof(struct udphdr
);
151 desc
.count
= skb
->len
- desc
.offset
;
153 if (skb
->ip_summed
== CHECKSUM_UNNECESSARY
)
156 desc
.csum
= csum_partial(skb
->data
, desc
.offset
, skb
->csum
);
157 if (xdr_partial_copy_from_skb(xdr
, 0, &desc
, skb_read_and_csum_bits
) < 0)
159 if (desc
.offset
!= skb
->len
) {
161 csum2
= skb_checksum(skb
, desc
.offset
, skb
->len
- desc
.offset
, 0);
162 desc
.csum
= csum_block_add(desc
.csum
, csum2
, desc
.offset
);
166 if ((unsigned short)csum_fold(desc
.csum
))
170 if (xdr_partial_copy_from_skb(xdr
, 0, &desc
, skb_read_bits
) < 0)