blob: 1d377d1ab7f4a5018a18a876f87e337c022346c3 [file] [log] [blame]
Chuck Lever094bb202005-08-11 16:25:20 -04001/*
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
Herbert Xufb286bb2005-11-10 13:01:24 -08009#include <linux/compiler.h>
10#include <linux/netdevice.h>
11#include <linux/skbuff.h>
Chuck Lever094bb202005-08-11 16:25:20 -040012#include <linux/types.h>
13#include <linux/pagemap.h>
14#include <linux/udp.h>
15#include <linux/sunrpc/xdr.h>
16
17
18/**
Chuck Lever9d292312006-12-05 16:35:41 -050019 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
Chuck Lever094bb202005-08-11 16:25:20 -040020 * @desc: sk_buff copy helper
21 * @to: copy destination
22 * @len: number of bytes to copy
23 *
24 * Possibly called several times to iterate over an sk_buff and copy
25 * data out of it.
26 */
Chuck Leverdd456472006-12-05 16:35:44 -050027size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
Chuck Lever094bb202005-08-11 16:25:20 -040028{
29 if (len > desc->count)
30 len = desc->count;
Chuck Lever9d292312006-12-05 16:35:41 -050031 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
Chuck Lever094bb202005-08-11 16:25:20 -040032 return 0;
33 desc->count -= len;
34 desc->offset += len;
35 return len;
36}
37
38/**
Chuck Lever9d292312006-12-05 16:35:41 -050039 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
Chuck Lever094bb202005-08-11 16:25:20 -040040 * @desc: sk_buff copy helper
41 * @to: copy destination
42 * @len: number of bytes to copy
43 *
44 * Same as skb_read_bits, but calculate a checksum at the same time.
45 */
Chuck Leverdd456472006-12-05 16:35:44 -050046static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
Chuck Lever094bb202005-08-11 16:25:20 -040047{
Al Viro5f92a732006-11-14 21:36:54 -080048 unsigned int pos;
49 __wsum csum2;
Chuck Lever094bb202005-08-11 16:25:20 -040050
51 if (len > desc->count)
52 len = desc->count;
53 pos = desc->offset;
54 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
55 desc->csum = csum_block_add(desc->csum, csum2, pos);
56 desc->count -= len;
57 desc->offset += len;
58 return len;
59}
60
61/**
62 * xdr_partial_copy_from_skb - copy data out of an skb
63 * @xdr: target XDR buffer
64 * @base: starting offset
65 * @desc: sk_buff copy helper
66 * @copy_actor: virtual method for copying data
67 *
68 */
Chuck Leverdd456472006-12-05 16:35:44 -050069ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
Chuck Lever094bb202005-08-11 16:25:20 -040070{
71 struct page **ppage = xdr->pages;
72 unsigned int len, pglen = xdr->page_len;
73 ssize_t copied = 0;
74 int ret;
75
76 len = xdr->head[0].iov_len;
77 if (base < len) {
78 len -= base;
79 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
80 copied += ret;
81 if (ret != len || !desc->count)
82 goto out;
83 base = 0;
84 } else
85 base -= len;
86
87 if (unlikely(pglen == 0))
88 goto copy_tail;
89 if (unlikely(base >= pglen)) {
90 base -= pglen;
91 goto copy_tail;
92 }
93 if (base || xdr->page_base) {
94 pglen -= base;
95 base += xdr->page_base;
96 ppage += base >> PAGE_CACHE_SHIFT;
97 base &= ~PAGE_CACHE_MASK;
98 }
99 do {
100 char *kaddr;
101
102 /* ACL likes to be lazy in allocating pages - ACLs
103 * are small by default but can get huge. */
104 if (unlikely(*ppage == NULL)) {
105 *ppage = alloc_page(GFP_ATOMIC);
106 if (unlikely(*ppage == NULL)) {
107 if (copied == 0)
108 copied = -ENOMEM;
109 goto out;
110 }
111 }
112
113 len = PAGE_CACHE_SIZE;
114 kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
115 if (base) {
116 len -= base;
117 if (pglen < len)
118 len = pglen;
119 ret = copy_actor(desc, kaddr + base, len);
120 base = 0;
121 } else {
122 if (pglen < len)
123 len = pglen;
124 ret = copy_actor(desc, kaddr, len);
125 }
126 flush_dcache_page(*ppage);
127 kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
128 copied += ret;
129 if (ret != len || !desc->count)
130 goto out;
131 ppage++;
132 } while ((pglen -= len) != 0);
133copy_tail:
134 len = xdr->tail[0].iov_len;
135 if (base < len)
136 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
137out:
138 return copied;
139}
140
141/**
142 * csum_partial_copy_to_xdr - checksum and copy data
143 * @xdr: target XDR buffer
144 * @skb: source skb
145 *
146 * We have set things up such that we perform the checksum of the UDP
147 * packet in parallel with the copies into the RPC client iovec. -DaveM
148 */
149int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
150{
Chuck Leverdd456472006-12-05 16:35:44 -0500151 struct xdr_skb_reader desc;
Chuck Lever094bb202005-08-11 16:25:20 -0400152
153 desc.skb = skb;
154 desc.offset = sizeof(struct udphdr);
155 desc.count = skb->len - desc.offset;
156
Herbert Xu60476372007-04-09 11:59:39 -0700157 if (skb_csum_unnecessary(skb))
Chuck Lever094bb202005-08-11 16:25:20 -0400158 goto no_checksum;
159
160 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
Chuck Lever9d292312006-12-05 16:35:41 -0500161 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
Chuck Lever094bb202005-08-11 16:25:20 -0400162 return -1;
163 if (desc.offset != skb->len) {
Al Viro5f92a732006-11-14 21:36:54 -0800164 __wsum csum2;
Chuck Lever094bb202005-08-11 16:25:20 -0400165 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
166 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
167 }
168 if (desc.count)
169 return -1;
Al Virod3bc23e2006-11-14 21:24:49 -0800170 if (csum_fold(desc.csum))
Chuck Lever094bb202005-08-11 16:25:20 -0400171 return -1;
Patrick McHardy84fa7932006-08-29 16:44:56 -0700172 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
Herbert Xufb286bb2005-11-10 13:01:24 -0800173 netdev_rx_csum_fault(skb->dev);
Chuck Lever094bb202005-08-11 16:25:20 -0400174 return 0;
175no_checksum:
Chuck Lever9d292312006-12-05 16:35:41 -0500176 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
Chuck Lever094bb202005-08-11 16:25:20 -0400177 return -1;
178 if (desc.count)
179 return -1;
180 return 0;
181}