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