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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// 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);