blob: 6f17527b9e695684038b2824443e2ab6a80a550e [file] [log] [blame]
Chuck Lever094bb202005-08-11 16:25:20 -04001/*
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
Herbert Xufb286bb2005-11-10 13:01:24 -08009#include <linux/compiler.h>
10#include <linux/netdevice.h>
11#include <linux/skbuff.h>
Chuck Lever094bb202005-08-11 16:25:20 -040012#include <linux/types.h>
13#include <linux/pagemap.h>
14#include <linux/udp.h>
15#include <linux/sunrpc/xdr.h>
16
17
18/**
19 * skb_read_bits - copy some data bits from skb to internal buffer
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 */
27static size_t skb_read_bits(skb_reader_t *desc, void *to, size_t len)
28{
29 if (len > desc->count)
30 len = desc->count;
31 if (skb_copy_bits(desc->skb, desc->offset, to, len))
32 return 0;
33 desc->count -= len;
34 desc->offset += len;
35 return len;
36}
37
38/**
39 * skb_read_and_csum_bits - copy and checksum from skb to buffer
40 * @desc: sk_buff copy helper
41 * @to: copy destination
42 * @len: number of bytes to copy
43 *
44 * Same as skb_read_bits, but calculate a checksum at the same time.
45 */
46static size_t skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
47{
48 unsigned int csum2, pos;
49
50 if (len > desc->count)
51 len = desc->count;
52 pos = desc->offset;
53 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
54 desc->csum = csum_block_add(desc->csum, csum2, pos);
55 desc->count -= len;
56 desc->offset += len;
57 return len;
58}
59
60/**
61 * xdr_partial_copy_from_skb - copy data out of an skb
62 * @xdr: target XDR buffer
63 * @base: starting offset
64 * @desc: sk_buff copy helper
65 * @copy_actor: virtual method for copying data
66 *
67 */
68ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, skb_reader_t *desc, skb_read_actor_t copy_actor)
69{
70 struct page **ppage = xdr->pages;
71 unsigned int len, pglen = xdr->page_len;
72 ssize_t copied = 0;
73 int ret;
74
75 len = xdr->head[0].iov_len;
76 if (base < len) {
77 len -= base;
78 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
79 copied += ret;
80 if (ret != len || !desc->count)
81 goto out;
82 base = 0;
83 } else
84 base -= len;
85
86 if (unlikely(pglen == 0))
87 goto copy_tail;
88 if (unlikely(base >= pglen)) {
89 base -= pglen;
90 goto copy_tail;
91 }
92 if (base || xdr->page_base) {
93 pglen -= base;
94 base += xdr->page_base;
95 ppage += base >> PAGE_CACHE_SHIFT;
96 base &= ~PAGE_CACHE_MASK;
97 }
98 do {
99 char *kaddr;
100
101 /* ACL likes to be lazy in allocating pages - ACLs
102 * are small by default but can get huge. */
103 if (unlikely(*ppage == NULL)) {
104 *ppage = alloc_page(GFP_ATOMIC);
105 if (unlikely(*ppage == NULL)) {
106 if (copied == 0)
107 copied = -ENOMEM;
108 goto out;
109 }
110 }
111
112 len = PAGE_CACHE_SIZE;
113 kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
114 if (base) {
115 len -= base;
116 if (pglen < len)
117 len = pglen;
118 ret = copy_actor(desc, kaddr + base, len);
119 base = 0;
120 } else {
121 if (pglen < len)
122 len = pglen;
123 ret = copy_actor(desc, kaddr, len);
124 }
125 flush_dcache_page(*ppage);
126 kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
127 copied += ret;
128 if (ret != len || !desc->count)
129 goto out;
130 ppage++;
131 } while ((pglen -= len) != 0);
132copy_tail:
133 len = xdr->tail[0].iov_len;
134 if (base < len)
135 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
136out:
137 return copied;
138}
139
140/**
141 * csum_partial_copy_to_xdr - checksum and copy data
142 * @xdr: target XDR buffer
143 * @skb: source skb
144 *
145 * We have set things up such that we perform the checksum of the UDP
146 * packet in parallel with the copies into the RPC client iovec. -DaveM
147 */
148int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
149{
150 skb_reader_t desc;
151
152 desc.skb = skb;
153 desc.offset = sizeof(struct udphdr);
154 desc.count = skb->len - desc.offset;
155
156 if (skb->ip_summed == CHECKSUM_UNNECESSARY)
157 goto no_checksum;
158
159 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
160 if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0)
161 return -1;
162 if (desc.offset != skb->len) {
163 unsigned int csum2;
164 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
165 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
166 }
167 if (desc.count)
168 return -1;
169 if ((unsigned short)csum_fold(desc.csum))
170 return -1;
Patrick McHardy84fa7932006-08-29 16:44:56 -0700171 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
Herbert Xufb286bb2005-11-10 13:01:24 -0800172 netdev_rx_csum_fault(skb->dev);
Chuck Lever094bb202005-08-11 16:25:20 -0400173 return 0;
174no_checksum:
175 if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0)
176 return -1;
177 if (desc.count)
178 return -1;
179 return 0;
180}