2 * iovec manipulation routines.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
11 * Andrew Lunn : Errors in iovec copying.
12 * Pedro Roque : Added memcpy_fromiovecend and
13 * csum_..._fromiovecend.
14 * Andi Kleen : fixed error handling for 2.1
15 * Alexey Kuznetsov: 2.1 optimisations
16 * Andi Kleen : Fix csum*fromiovecend for IPv6.
19 #include <linux/errno.h>
20 #include <linux/module.h>
21 #include <linux/kernel.h>
23 #include <linux/net.h>
24 #include <linux/in6.h>
25 #include <asm/uaccess.h>
26 #include <asm/byteorder.h>
27 #include <net/checksum.h>
31 * Verify iovec. The caller must ensure that the iovec is big enough
32 * to hold the message iovec.
34 * Save time not doing access_ok. copy_*_user will make this work
38 int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *address, int mode)
43 if (mode == VERIFY_READ) {
45 namep = (void __user __force *) m->msg_name;
46 err = move_addr_to_kernel(namep, m->msg_namelen,
52 m->msg_name = address;
57 size = m->msg_iovlen * sizeof(struct iovec);
58 if (copy_from_user(iov, (void __user __force *) m->msg_iov, size))
64 for (ct = 0; ct < m->msg_iovlen; ct++) {
65 size_t len = iov[ct].iov_len;
67 if (len > INT_MAX - err) {
69 iov[ct].iov_len = len;
78 * Copy kernel to iovec. Returns -EFAULT on error.
81 int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
85 for (; len > 0; ++iov) {
86 /* Skip over the finished iovecs */
87 if (unlikely(offset >= iov->iov_len)) {
88 offset -= iov->iov_len;
91 copy = min_t(unsigned int, iov->iov_len - offset, len);
92 if (copy_to_user(iov->iov_base + offset, kdata, copy))
101 EXPORT_SYMBOL(memcpy_toiovecend);
104 * Copy iovec to kernel. Returns -EFAULT on error.
107 int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
110 /* Skip over the finished iovecs */
111 while (offset >= iov->iov_len) {
112 offset -= iov->iov_len;
117 u8 __user *base = iov->iov_base + offset;
118 int copy = min_t(unsigned int, len, iov->iov_len - offset);
121 if (copy_from_user(kdata, base, copy))
130 EXPORT_SYMBOL(memcpy_fromiovecend);
133 * And now for the all-in-one: copy and checksum from a user iovec
134 * directly to a datagram
135 * Calls to csum_partial but the last must be in 32 bit chunks
137 * ip_build_xmit must ensure that when fragmenting only the last
138 * call to this function will be unaligned also.
140 int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
141 int offset, unsigned int len, __wsum *csump)
143 __wsum csum = *csump;
144 int partial_cnt = 0, err = 0;
146 /* Skip over the finished iovecs */
147 while (offset >= iov->iov_len) {
148 offset -= iov->iov_len;
153 u8 __user *base = iov->iov_base + offset;
154 int copy = min_t(unsigned int, len, iov->iov_len - offset);
158 /* There is a remnant from previous iov. */
160 int par_len = 4 - partial_cnt;
162 /* iov component is too short ... */
163 if (par_len > copy) {
164 if (copy_from_user(kdata, base, copy))
173 *csump = csum_partial(kdata - partial_cnt,
177 if (copy_from_user(kdata, base, par_len))
179 csum = csum_partial(kdata - partial_cnt, 4, csum);
188 partial_cnt = copy % 4;
191 if (copy_from_user(kdata + copy, base + copy,
198 csum = csum_and_copy_from_user(base, kdata, copy,
203 len -= copy + partial_cnt;
204 kdata += copy + partial_cnt;
215 EXPORT_SYMBOL(csum_partial_copy_fromiovecend);
217 unsigned long iov_pages(const struct iovec *iov, int offset,
218 unsigned long nr_segs)
220 unsigned long seg, base;
221 int pages = 0, len, size;
223 while (nr_segs && (offset >= iov->iov_len)) {
224 offset -= iov->iov_len;
229 for (seg = 0; seg < nr_segs; seg++) {
230 base = (unsigned long)iov[seg].iov_base + offset;
231 len = iov[seg].iov_len - offset;
232 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
239 EXPORT_SYMBOL(iov_pages);