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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/net/sunrpc/socklib.c
4 *
5 * Common socket helper routines for RPC client and server
6 *
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8 */
9
10#include <linux/compiler.h>
11#include <linux/netdevice.h>
12#include <linux/gfp.h>
13#include <linux/skbuff.h>
14#include <linux/types.h>
15#include <linux/pagemap.h>
16#include <linux/udp.h>
17#include <linux/sunrpc/xdr.h>
18#include <linux/export.h>
19
20
21/**
22 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
23 * @desc: sk_buff copy helper
24 * @to: copy destination
25 * @len: number of bytes to copy
26 *
27 * Possibly called several times to iterate over an sk_buff and copy
28 * data out of it.
29 */
30static size_t
31xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
32{
33 if (len > desc->count)
34 len = desc->count;
35 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
36 return 0;
37 desc->count -= len;
38 desc->offset += len;
39 return len;
40}
41
42/**
43 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
44 * @desc: sk_buff copy helper
45 * @to: copy destination
46 * @len: number of bytes to copy
47 *
48 * Same as skb_read_bits, but calculate a checksum at the same time.
49 */
50static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
51{
52 unsigned int pos;
53 __wsum csum2;
54
55 if (len > desc->count)
56 len = desc->count;
57 pos = desc->offset;
58 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
59 desc->csum = csum_block_add(desc->csum, csum2, pos);
60 desc->count -= len;
61 desc->offset += len;
62 return len;
63}
64
65/**
66 * xdr_partial_copy_from_skb - copy data out of an skb
67 * @xdr: target XDR buffer
68 * @base: starting offset
69 * @desc: sk_buff copy helper
70 * @copy_actor: virtual method for copying data
71 *
72 */
73static ssize_t
74xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
75{
76 struct page **ppage = xdr->pages;
77 unsigned int len, pglen = xdr->page_len;
78 ssize_t copied = 0;
79 size_t ret;
80
81 len = xdr->head[0].iov_len;
82 if (base < len) {
83 len -= base;
84 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
85 copied += ret;
86 if (ret != len || !desc->count)
87 goto out;
88 base = 0;
89 } else
90 base -= len;
91
92 if (unlikely(pglen == 0))
93 goto copy_tail;
94 if (unlikely(base >= pglen)) {
95 base -= pglen;
96 goto copy_tail;
97 }
98 if (base || xdr->page_base) {
99 pglen -= base;
100 base += xdr->page_base;
101 ppage += base >> PAGE_SHIFT;
102 base &= ~PAGE_MASK;
103 }
104 do {
105 char *kaddr;
106
107 /* ACL likes to be lazy in allocating pages - ACLs
108 * are small by default but can get huge. */
109 if ((xdr->flags & XDRBUF_SPARSE_PAGES) && *ppage == NULL) {
110 *ppage = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
111 if (unlikely(*ppage == NULL)) {
112 if (copied == 0)
113 copied = -ENOMEM;
114 goto out;
115 }
116 }
117
118 len = PAGE_SIZE;
119 kaddr = kmap_atomic(*ppage);
120 if (base) {
121 len -= base;
122 if (pglen < len)
123 len = pglen;
124 ret = copy_actor(desc, kaddr + base, len);
125 base = 0;
126 } else {
127 if (pglen < len)
128 len = pglen;
129 ret = copy_actor(desc, kaddr, len);
130 }
131 flush_dcache_page(*ppage);
132 kunmap_atomic(kaddr);
133 copied += ret;
134 if (ret != len || !desc->count)
135 goto out;
136 ppage++;
137 } while ((pglen -= len) != 0);
138copy_tail:
139 len = xdr->tail[0].iov_len;
140 if (base < len)
141 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
142out:
143 return copied;
144}
145
146/**
147 * csum_partial_copy_to_xdr - checksum and copy data
148 * @xdr: target XDR buffer
149 * @skb: source skb
150 *
151 * We have set things up such that we perform the checksum of the UDP
152 * packet in parallel with the copies into the RPC client iovec. -DaveM
153 */
154int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
155{
156 struct xdr_skb_reader desc;
157
158 desc.skb = skb;
159 desc.offset = 0;
160 desc.count = skb->len - desc.offset;
161
162 if (skb_csum_unnecessary(skb))
163 goto no_checksum;
164
165 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
166 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
167 return -1;
168 if (desc.offset != skb->len) {
169 __wsum csum2;
170 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
171 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
172 }
173 if (desc.count)
174 return -1;
175 if (csum_fold(desc.csum))
176 return -1;
177 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
178 !skb->csum_complete_sw)
179 netdev_rx_csum_fault(skb->dev, skb);
180 return 0;
181no_checksum:
182 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
183 return -1;
184 if (desc.count)
185 return -1;
186 return 0;
187}
188EXPORT_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#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 = 0;
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);