1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/net/sunrpc/socklib.c
5 * Common socket helper routines for RPC client and server
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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>
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
27 * Possibly called several times to iterate over an sk_buff and copy
31 xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
33 if (len > desc->count)
35 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
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
48 * Same as skb_read_bits, but calculate a checksum at the same time.
50 static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
55 if (len > desc->count)
58 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
59 desc->csum = csum_block_add(desc->csum, csum2, pos);
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
74 xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
76 struct page **ppage = xdr->pages;
77 unsigned int len, pglen = xdr->page_len;
81 len = xdr->head[0].iov_len;
84 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
86 if (ret != len || !desc->count)
92 if (unlikely(pglen == 0))
94 if (unlikely(base >= pglen)) {
98 if (base || xdr->page_base) {
100 base += xdr->page_base;
101 ppage += base >> PAGE_SHIFT;
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)) {
119 kaddr = kmap_atomic(*ppage);
124 ret = copy_actor(desc, kaddr + base, len);
129 ret = copy_actor(desc, kaddr, len);
131 flush_dcache_page(*ppage);
132 kunmap_atomic(kaddr);
134 if (ret != len || !desc->count)
137 } while ((pglen -= len) != 0);
139 len = xdr->tail[0].iov_len;
141 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
147 * csum_partial_copy_to_xdr - checksum and copy data
148 * @xdr: target XDR buffer
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
154 int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
156 struct xdr_skb_reader desc;
160 desc.count = skb->len - desc.offset;
162 if (skb_csum_unnecessary(skb))
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)
168 if (desc.offset != skb->len) {
170 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
171 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
175 if (csum_fold(desc.csum))
177 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
178 !skb->csum_complete_sw)
179 netdev_rx_csum_fault(skb->dev, skb);
182 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
188 EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);