138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
/*
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* iovec manipulation routines.
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Fixes:
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* Andrew Lunn : Errors in iovec copying.
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* Pedro Roque : Added memcpy_fromiovecend and
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* csum_..._fromiovecend.
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* Andi Kleen : fixed error handling for 2.1
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* Alexey Kuznetsov: 2.1 optimisations
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* Andi Kleen : Fix csum*fromiovecend for IPv6.
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*/
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/net.h>
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#include <linux/in6.h>
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#include <asm/uaccess.h>
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#include <asm/byteorder.h>
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#include <net/checksum.h>
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#include <net/sock.h>
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/*
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* And now for the all-in-one: copy and checksum from a user iovec
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* directly to a datagram
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* Calls to csum_partial but the last must be in 32 bit chunks
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*
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* ip_build_xmit must ensure that when fragmenting only the last
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* call to this function will be unaligned also.
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*/
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int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
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int offset, unsigned int len, __wsum *csump)
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{
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__wsum csum = *csump;
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int partial_cnt = 0, err = 0;
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/* Skip over the finished iovecs */
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while (offset >= iov->iov_len) {
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offset -= iov->iov_len;
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iov++;
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}
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while (len > 0) {
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u8 __user *base = iov->iov_base + offset;
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int copy = min_t(unsigned int, len, iov->iov_len - offset);
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offset = 0;
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/* There is a remnant from previous iov. */
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if (partial_cnt) {
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int par_len = 4 - partial_cnt;
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/* iov component is too short ... */
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if (par_len > copy) {
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if (copy_from_user(kdata, base, copy))
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goto out_fault;
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kdata += copy;
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base += copy;
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partial_cnt += copy;
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len -= copy;
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iov++;
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if (len)
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continue;
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*csump = csum_partial(kdata - partial_cnt,
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partial_cnt, csum);
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goto out;
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}
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if (copy_from_user(kdata, base, par_len))
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goto out_fault;
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csum = csum_partial(kdata - partial_cnt, 4, csum);
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kdata += par_len;
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base += par_len;
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copy -= par_len;
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len -= par_len;
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partial_cnt = 0;
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}
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if (len > copy) {
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partial_cnt = copy % 4;
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if (partial_cnt) {
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copy -= partial_cnt;
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if (copy_from_user(kdata + copy, base + copy,
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partial_cnt))
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goto out_fault;
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}
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}
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if (copy) {
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csum = csum_and_copy_from_user(base, kdata, copy,
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csum, &err);
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if (err)
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goto out;
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}
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len -= copy + partial_cnt;
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kdata += copy + partial_cnt;
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iov++;
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}
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*csump = csum;
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out:
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return err;
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out_fault:
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err = -EFAULT;
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goto out;
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}
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EXPORT_SYMBOL(csum_partial_copy_fromiovecend);
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unsigned long iov_pages(const struct iovec *iov, int offset,
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unsigned long nr_segs)
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{
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unsigned long seg, base;
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int pages = 0, len, size;
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while (nr_segs && (offset >= iov->iov_len)) {
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offset -= iov->iov_len;
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++iov;
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--nr_segs;
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}
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for (seg = 0; seg < nr_segs; seg++) {
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base = (unsigned long)iov[seg].iov_base + offset;
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len = iov[seg].iov_len - offset;
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size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
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pages += size;
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offset = 0;
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}
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return pages;
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}
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EXPORT_SYMBOL(iov_pages);
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