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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/msg_prot.h>
18#include <linux/sunrpc/xdr.h>
19#include <linux/export.h>
20
21#include "socklib.h"
22
23/*
24 * Helper structure for copying from an sk_buff.
25 */
26struct xdr_skb_reader {
27 struct sk_buff *skb;
28 unsigned int offset;
29 size_t count;
30 __wsum csum;
31};
32
33typedef size_t (*xdr_skb_read_actor)(struct xdr_skb_reader *desc, void *to,
34 size_t len);
35
36/**
37 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
38 * @desc: sk_buff copy helper
39 * @to: copy destination
40 * @len: number of bytes to copy
41 *
42 * Possibly called several times to iterate over an sk_buff and copy
43 * data out of it.
44 */
45static size_t
46xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
47{
48 if (len > desc->count)
49 len = desc->count;
50 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
51 return 0;
52 desc->count -= len;
53 desc->offset += len;
54 return len;
55}
56
57/**
58 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
59 * @desc: sk_buff copy helper
60 * @to: copy destination
61 * @len: number of bytes to copy
62 *
63 * Same as skb_read_bits, but calculate a checksum at the same time.
64 */
65static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
66{
67 unsigned int pos;
68 __wsum csum2;
69
70 if (len > desc->count)
71 len = desc->count;
72 pos = desc->offset;
73 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
74 desc->csum = csum_block_add(desc->csum, csum2, pos);
75 desc->count -= len;
76 desc->offset += len;
77 return len;
78}
79
80/**
81 * xdr_partial_copy_from_skb - copy data out of an skb
82 * @xdr: target XDR buffer
83 * @base: starting offset
84 * @desc: sk_buff copy helper
85 * @copy_actor: virtual method for copying data
86 *
87 */
88static ssize_t
89xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
90{
91 struct page **ppage = xdr->pages;
92 unsigned int len, pglen = xdr->page_len;
93 ssize_t copied = 0;
94 size_t ret;
95
96 len = xdr->head[0].iov_len;
97 if (base < len) {
98 len -= base;
99 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
100 copied += ret;
101 if (ret != len || !desc->count)
102 goto out;
103 base = 0;
104 } else
105 base -= len;
106
107 if (unlikely(pglen == 0))
108 goto copy_tail;
109 if (unlikely(base >= pglen)) {
110 base -= pglen;
111 goto copy_tail;
112 }
113 if (base || xdr->page_base) {
114 pglen -= base;
115 base += xdr->page_base;
116 ppage += base >> PAGE_SHIFT;
117 base &= ~PAGE_MASK;
118 }
119 do {
120 char *kaddr;
121
122 /* ACL likes to be lazy in allocating pages - ACLs
123 * are small by default but can get huge. */
124 if ((xdr->flags & XDRBUF_SPARSE_PAGES) && *ppage == NULL) {
125 *ppage = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
126 if (unlikely(*ppage == NULL)) {
127 if (copied == 0)
128 copied = -ENOMEM;
129 goto out;
130 }
131 }
132
133 len = PAGE_SIZE;
134 kaddr = kmap_atomic(*ppage);
135 if (base) {
136 len -= base;
137 if (pglen < len)
138 len = pglen;
139 ret = copy_actor(desc, kaddr + base, len);
140 base = 0;
141 } else {
142 if (pglen < len)
143 len = pglen;
144 ret = copy_actor(desc, kaddr, len);
145 }
146 flush_dcache_page(*ppage);
147 kunmap_atomic(kaddr);
148 copied += ret;
149 if (ret != len || !desc->count)
150 goto out;
151 ppage++;
152 } while ((pglen -= len) != 0);
153copy_tail:
154 len = xdr->tail[0].iov_len;
155 if (base < len)
156 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
157out:
158 return copied;
159}
160
161/**
162 * csum_partial_copy_to_xdr - checksum and copy data
163 * @xdr: target XDR buffer
164 * @skb: source skb
165 *
166 * We have set things up such that we perform the checksum of the UDP
167 * packet in parallel with the copies into the RPC client iovec. -DaveM
168 */
169int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
170{
171 struct xdr_skb_reader desc;
172
173 desc.skb = skb;
174 desc.offset = 0;
175 desc.count = skb->len - desc.offset;
176
177 if (skb_csum_unnecessary(skb))
178 goto no_checksum;
179
180 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
181 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
182 return -1;
183 if (desc.offset != skb->len) {
184 __wsum csum2;
185 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
186 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
187 }
188 if (desc.count)
189 return -1;
190 if (csum_fold(desc.csum))
191 return -1;
192 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
193 !skb->csum_complete_sw)
194 netdev_rx_csum_fault(skb->dev, skb);
195 return 0;
196no_checksum:
197 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
198 return -1;
199 if (desc.count)
200 return -1;
201 return 0;
202}
203EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);
204
205static inline int xprt_sendmsg(struct socket *sock, struct msghdr *msg,
206 size_t seek)
207{
208 if (seek)
209 iov_iter_advance(&msg->msg_iter, seek);
210 return sock_sendmsg(sock, msg);
211}
212
213static int xprt_send_kvec(struct socket *sock, struct msghdr *msg,
214 struct kvec *vec, size_t seek)
215{
216 iov_iter_kvec(&msg->msg_iter, WRITE, vec, 1, vec->iov_len);
217 return xprt_sendmsg(sock, msg, seek);
218}
219
220static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg,
221 struct xdr_buf *xdr, size_t base)
222{
223 int err;
224
225 err = xdr_alloc_bvec(xdr, GFP_KERNEL);
226 if (err < 0)
227 return err;
228
229 iov_iter_bvec(&msg->msg_iter, WRITE, xdr->bvec, xdr_buf_pagecount(xdr),
230 xdr->page_len + xdr->page_base);
231 return xprt_sendmsg(sock, msg, base + xdr->page_base);
232}
233
234/* Common case:
235 * - stream transport
236 * - sending from byte 0 of the message
237 * - the message is wholly contained in @xdr's head iovec
238 */
239static int xprt_send_rm_and_kvec(struct socket *sock, struct msghdr *msg,
240 rpc_fraghdr marker, struct kvec *vec,
241 size_t base)
242{
243 struct kvec iov[2] = {
244 [0] = {
245 .iov_base = &marker,
246 .iov_len = sizeof(marker)
247 },
248 [1] = *vec,
249 };
250 size_t len = iov[0].iov_len + iov[1].iov_len;
251
252 iov_iter_kvec(&msg->msg_iter, WRITE, iov, 2, len);
253 return xprt_sendmsg(sock, msg, base);
254}
255
256/**
257 * xprt_sock_sendmsg - write an xdr_buf directly to a socket
258 * @sock: open socket to send on
259 * @msg: socket message metadata
260 * @xdr: xdr_buf containing this request
261 * @base: starting position in the buffer
262 * @marker: stream record marker field
263 * @sent_p: return the total number of bytes successfully queued for sending
264 *
265 * Return values:
266 * On success, returns zero and fills in @sent_p.
267 * %-ENOTSOCK if @sock is not a struct socket.
268 */
269int xprt_sock_sendmsg(struct socket *sock, struct msghdr *msg,
270 struct xdr_buf *xdr, unsigned int base,
271 rpc_fraghdr marker, unsigned int *sent_p)
272{
273 unsigned int rmsize = marker ? sizeof(marker) : 0;
274 unsigned int remainder = rmsize + xdr->len - base;
275 unsigned int want;
276 int err = 0;
277
278 *sent_p = 0;
279
280 if (unlikely(!sock))
281 return -ENOTSOCK;
282
283 msg->msg_flags |= MSG_MORE;
284 want = xdr->head[0].iov_len + rmsize;
285 if (base < want) {
286 unsigned int len = want - base;
287
288 remainder -= len;
289 if (remainder == 0)
290 msg->msg_flags &= ~MSG_MORE;
291 if (rmsize)
292 err = xprt_send_rm_and_kvec(sock, msg, marker,
293 &xdr->head[0], base);
294 else
295 err = xprt_send_kvec(sock, msg, &xdr->head[0], base);
296 if (remainder == 0 || err != len)
297 goto out;
298 *sent_p += err;
299 base = 0;
300 } else {
301 base -= want;
302 }
303
304 if (base < xdr->page_len) {
305 unsigned int len = xdr->page_len - base;
306
307 remainder -= len;
308 if (remainder == 0)
309 msg->msg_flags &= ~MSG_MORE;
310 err = xprt_send_pagedata(sock, msg, xdr, base);
311 if (remainder == 0 || err != len)
312 goto out;
313 *sent_p += err;
314 base = 0;
315 } else {
316 base -= xdr->page_len;
317 }
318
319 if (base >= xdr->tail[0].iov_len)
320 return 0;
321 msg->msg_flags &= ~MSG_MORE;
322 err = xprt_send_kvec(sock, msg, &xdr->tail[0], base);
323out:
324 if (err > 0) {
325 *sent_p += err;
326 err = 0;
327 }
328 return err;
329}
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);