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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
9#include <linux/compiler.h>
10#include <linux/netdevice.h>
11#include <linux/gfp.h>
12#include <linux/skbuff.h>
13#include <linux/types.h>
14#include <linux/pagemap.h>
15#include <linux/udp.h>
16#include <linux/sunrpc/xdr.h>
17#include <linux/export.h>
18
19
20/**
21 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
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 */
29size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
30{
31 if (len > desc->count)
32 len = desc->count;
33 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
34 return 0;
35 desc->count -= len;
36 desc->offset += len;
37 return len;
38}
39EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
40
41/**
42 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
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 */
49static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
50{
51 unsigned int pos;
52 __wsum csum2;
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 */
72ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
73{
74 struct page **ppage = xdr->pages;
75 unsigned int len, pglen = xdr->page_len;
76 ssize_t copied = 0;
77 size_t ret;
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;
99 ppage += base >> PAGE_SHIFT;
100 base &= ~PAGE_MASK;
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
116 len = PAGE_SIZE;
117 kaddr = kmap_atomic(*ppage);
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);
130 kunmap_atomic(kaddr);
131 copied += ret;
132 if (ret != len || !desc->count)
133 goto out;
134 ppage++;
135 } while ((pglen -= len) != 0);
136copy_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);
140out:
141 return copied;
142}
143EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
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 */
153int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
154{
155 struct xdr_skb_reader desc;
156
157 desc.skb = skb;
158 desc.offset = sizeof(struct udphdr);
159 desc.count = skb->len - desc.offset;
160
161 if (skb_csum_unnecessary(skb))
162 goto no_checksum;
163
164 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
165 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
166 return -1;
167 if (desc.offset != skb->len) {
168 __wsum csum2;
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;
174 if (csum_fold(desc.csum))
175 return -1;
176 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
177 !skb->csum_complete_sw)
178 netdev_rx_csum_fault(skb->dev);
179 return 0;
180no_checksum:
181 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
182 return -1;
183 if (desc.count)
184 return -1;
185 return 0;
186}
187EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);
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
9#include <linux/compiler.h>
10#include <linux/netdevice.h>
11#include <linux/gfp.h>
12#include <linux/skbuff.h>
13#include <linux/types.h>
14#include <linux/pagemap.h>
15#include <linux/udp.h>
16#include <linux/sunrpc/xdr.h>
17
18
19/**
20 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
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 */
28size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
29{
30 if (len > desc->count)
31 len = desc->count;
32 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
33 return 0;
34 desc->count -= len;
35 desc->offset += len;
36 return len;
37}
38EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
39
40/**
41 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
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 */
48static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
49{
50 unsigned int pos;
51 __wsum csum2;
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 */
71ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
72{
73 struct page **ppage = xdr->pages;
74 unsigned int len, pglen = xdr->page_len;
75 ssize_t copied = 0;
76 size_t ret;
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);
135copy_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);
139out:
140 return copied;
141}
142EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
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 */
152int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
153{
154 struct xdr_skb_reader desc;
155
156 desc.skb = skb;
157 desc.offset = sizeof(struct udphdr);
158 desc.count = skb->len - desc.offset;
159
160 if (skb_csum_unnecessary(skb))
161 goto no_checksum;
162
163 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
164 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
165 return -1;
166 if (desc.offset != skb->len) {
167 __wsum csum2;
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;
173 if (csum_fold(desc.csum))
174 return -1;
175 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
176 netdev_rx_csum_fault(skb->dev);
177 return 0;
178no_checksum:
179 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
180 return -1;
181 if (desc.count)
182 return -1;
183 return 0;
184}
185EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);