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.
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
24 #include <linux/slab.h>
25 #include <linux/net.h>
26 #include <linux/in6.h>
27 #include <asm/uaccess.h>
28 #include <asm/byteorder.h>
29 #include <net/checksum.h>
33 * Verify iovec. The caller must ensure that the iovec is big enough
34 * to hold the message iovec.
36 * Save time not doing verify_area. copy_*_user will make this work
40 int verify_iovec(struct msghdr *m, struct iovec *iov, char *address, int mode)
48 err=move_addr_to_kernel(m->msg_name, m->msg_namelen, address);
53 m->msg_name = address;
58 size = m->msg_iovlen * sizeof(struct iovec);
59 if (copy_from_user(iov, m->msg_iov, size))
63 for (err = 0, ct = 0; ct < m->msg_iovlen; ct++) {
64 err += iov[ct].iov_len;
65 /* Goal is not to verify user data, but to prevent returning
66 negative value, which is interpreted as errno.
67 Overflow is still possible, but it is harmless.
77 * Copy kernel to iovec. Returns -EFAULT on error.
79 * Note: this modifies the original iovec.
82 int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
90 int copy = min_t(unsigned int, iov->iov_len, len);
91 if (copy_to_user(iov->iov_base, kdata, copy))
106 * In kernel copy to iovec. Returns -EFAULT on error.
108 * Note: this modifies the original iovec.
111 void memcpy_tokerneliovec(struct iovec *iov, unsigned char *kdata, int len)
117 int copy = min_t(unsigned int, iov->iov_len, len);
118 memcpy(iov->iov_base, kdata, copy);
130 * Copy iovec to kernel. Returns -EFAULT on error.
132 * Note: this modifies the original iovec.
135 int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
143 int copy = min_t(unsigned int, len, iov->iov_len);
144 if (copy_from_user(kdata, iov->iov_base, copy))
160 * For use with ip_build_xmit
163 int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset,
168 /* Skip over the finished iovecs */
169 while(offset >= iov->iov_len)
171 offset -= iov->iov_len;
177 u8 *base = iov->iov_base + offset;
178 int copy = min_t(unsigned int, len, iov->iov_len - offset);
181 if (copy_from_user(kdata, base, copy))
193 * And now for the all-in-one: copy and checksum from a user iovec
194 * directly to a datagram
195 * Calls to csum_partial but the last must be in 32 bit chunks
197 * ip_build_xmit must ensure that when fragmenting only the last
198 * call to this function will be unaligned also.
201 int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
202 int offset, unsigned int len, int *csump)
205 int partial_cnt = 0, err = 0;
207 /* Skip over the finished iovecs */
208 while (offset >= iov->iov_len)
210 offset -= iov->iov_len;
216 u8 *base = iov->iov_base + offset;
217 int copy = min_t(unsigned int, len, iov->iov_len - offset);
220 /* There is a remnant from previous iov. */
223 int par_len = 4 - partial_cnt;
225 /* iov component is too short ... */
226 if (par_len > copy) {
227 if (copy_from_user(kdata, base, copy))
236 *csump = csum_partial(kdata - partial_cnt,
240 if (copy_from_user(kdata, base, par_len))
242 csum = csum_partial(kdata - partial_cnt, 4, csum);
252 partial_cnt = copy % 4;
256 if (copy_from_user(kdata + copy, base + copy,
263 csum = csum_and_copy_from_user(base, kdata, copy,
268 len -= copy + partial_cnt;
269 kdata += copy + partial_cnt;