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)
42 if (m->msg_name && m->msg_namelen) {
43 if (mode == VERIFY_READ) {
45 namep = (void __user __force *) m->msg_name;
46 err = move_addr_to_kernel(namep, m->msg_namelen,
51 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 from kernel. Returns -EFAULT on error.
107 int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
114 /* Skip over the finished iovecs */
115 while (offset >= iov->iov_len) {
116 offset -= iov->iov_len;
121 u8 __user *base = iov->iov_base + offset;
122 int copy = min_t(unsigned int, len, iov->iov_len - offset);
125 if (copy_from_user(kdata, base, copy))
134 EXPORT_SYMBOL(memcpy_fromiovecend);
137 * And now for the all-in-one: copy and checksum from a user iovec
138 * directly to a datagram
139 * Calls to csum_partial but the last must be in 32 bit chunks
141 * ip_build_xmit must ensure that when fragmenting only the last
142 * call to this function will be unaligned also.
144 int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
145 int offset, unsigned int len, __wsum *csump)
147 __wsum csum = *csump;
148 int partial_cnt = 0, err = 0;
150 /* Skip over the finished iovecs */
151 while (offset >= iov->iov_len) {
152 offset -= iov->iov_len;
157 u8 __user *base = iov->iov_base + offset;
158 int copy = min_t(unsigned int, len, iov->iov_len - offset);
162 /* There is a remnant from previous iov. */
164 int par_len = 4 - partial_cnt;
166 /* iov component is too short ... */
167 if (par_len > copy) {
168 if (copy_from_user(kdata, base, copy))
177 *csump = csum_partial(kdata - partial_cnt,
181 if (copy_from_user(kdata, base, par_len))
183 csum = csum_partial(kdata - partial_cnt, 4, csum);
192 partial_cnt = copy % 4;
195 if (copy_from_user(kdata + copy, base + copy,
202 csum = csum_and_copy_from_user(base, kdata, copy,
207 len -= copy + partial_cnt;
208 kdata += copy + partial_cnt;
219 EXPORT_SYMBOL(csum_partial_copy_fromiovecend);