/*
 *  linux/fs/hfs/trans.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * This file contains routines for converting between the Macintosh
 * character set and various other encodings.  This includes dealing
 * with ':' vs. '/' as the path-element separator.
 */

#include <linux/types.h>
#include <linux/nls.h>

#include "hfs_fs.h"

/*================ Global functions ================*/

/*
 * hfs_mac2asc()
 *
 * Given a 'Pascal String' (a string preceded by a length byte) in
 * the Macintosh character set produce the corresponding filename using
 * the 'trivial' name-mangling scheme, returning the length of the
 * mangled filename.  Note that the output string is not NULL
 * terminated.
 *
 * The name-mangling works as follows:
 * The character '/', which is illegal in Linux filenames is replaced
 * by ':' which never appears in HFS filenames.	 All other characters
 * are passed unchanged from input to output.
 */
int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in)
{
	struct nls_table *nls_disk = HFS_SB(sb)->nls_disk;
	struct nls_table *nls_io = HFS_SB(sb)->nls_io;
	const char *src;
	char *dst;
	int srclen, dstlen, size;

	src = in->name;
	srclen = in->len;
	if (srclen > HFS_NAMELEN)
		srclen = HFS_NAMELEN;
	dst = out;
	dstlen = HFS_MAX_NAMELEN;
	if (nls_io) {
		wchar_t ch;

		while (srclen > 0) {
			if (nls_disk) {
				size = nls_disk->char2uni(src, srclen, &ch);
				if (size <= 0) {
					ch = '?';
					size = 1;
				}
				src += size;
				srclen -= size;
			} else {
				ch = *src++;
				srclen--;
			}
			if (ch == '/')
				ch = ':';
			size = nls_io->uni2char(ch, dst, dstlen);
			if (size < 0) {
				if (size == -ENAMETOOLONG)
					goto out;
				*dst = '?';
				size = 1;
			}
			dst += size;
			dstlen -= size;
		}
	} else {
		char ch;

		while (--srclen >= 0)
			*dst++ = (ch = *src++) == '/' ? ':' : ch;
	}
out:
	return dst - out;
}

/*
 * hfs_asc2mac()
 *
 * Given an ASCII string (not null-terminated) and its length,
 * generate the corresponding filename in the Macintosh character set
 * using the 'trivial' name-mangling scheme, returning the length of
 * the mangled filename.  Note that the output string is not NULL
 * terminated.
 *
 * This routine is a inverse to hfs_mac2triv().
 * A ':' is replaced by a '/'.
 */
void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr *in)
{
	struct nls_table *nls_disk = HFS_SB(sb)->nls_disk;
	struct nls_table *nls_io = HFS_SB(sb)->nls_io;
	const char *src;
	char *dst;
	int srclen, dstlen, size;

	src = in->name;
	srclen = in->len;
	dst = out->name;
	dstlen = HFS_NAMELEN;
	if (nls_io) {
		wchar_t ch;

		while (srclen > 0) {
			size = nls_io->char2uni(src, srclen, &ch);
			if (size < 0) {
				ch = '?';
				size = 1;
			}
			src += size;
			srclen -= size;
			if (ch == ':')
				ch = '/';
			if (nls_disk) {
				size = nls_disk->uni2char(ch, dst, dstlen);
				if (size < 0) {
					if (size == -ENAMETOOLONG)
						goto out;
					*dst = '?';
					size = 1;
				}
				dst += size;
				dstlen -= size;
			} else {
				*dst++ = ch > 0xff ? '?' : ch;
				dstlen--;
			}
		}
	} else {
		char ch;

		if (dstlen > srclen)
			dstlen = srclen;
		while (--dstlen >= 0)
			*dst++ = (ch = *src++) == ':' ? '/' : ch;
	}
out:
	out->len = dst - (char *)out->name;
	dstlen = HFS_NAMELEN - out->len;
	while (--dstlen >= 0)
		*dst++ = 0;
}
llapse</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr class='logheader'><td><span title='2017-01-31 13:16:59 -0500'>2017-01-31</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/ipv6.h?id=90427ef5d2a4b9a24079889bf16afdcdaebc4240'>ipv6: fix flow labels when the traffic class is non-0</a></td><td>Dimitris Michailidis</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+5</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
ip6_make_flowlabel() determines the flow label for IPv6 packets. It's
supposed to be passed a flow label, which it returns as is if non-0 and
in some other cases, otherwise it calculates a new value.

The problem is callers often pass a flowi6.flowlabel, which may also
contain traffic class bits. If the traffic class is non-0
ip6_make_flowlabel() mistakes the non-0 it gets as a flow label and
returns the whole thing. Thus it can return a 'flow label' longer than
20b and the low 20b of that is typically 0 resulting in packets with 0
label. Moreover, different packets of a flow may be labeled differently.
For a TCP flow with ECN non-payload and payload packets get different
labels as exemplified by this pair of consecutive packets:

(pure ACK)
Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    .... .... .... 0001 1100 1110 0100 1001 = Flow Label: 0x1ce49
    Payload Length: 32
    Next Header: TCP (6)

(payload)
Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0))
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2)
    .... .... .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000
    Payload Length: 688
    Next Header: TCP (6)

This patch allows ip6_make_flowlabel() to be passed more than just a
flow label and has it extract the part it really wants. This was simpler
than modifying the callers. With this patch packets like the above become

Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e
    Payload Length: 32
    Next Header: TCP (6)

Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0))
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2)
    .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e
    Payload Length: 688
    Next Header: TCP (6)

Signed-off-by: Dimitris Michailidis &lt;dmichail@google.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;


</td></tr>