summaryrefslogtreecommitdiffstats
path: root/lib/isc/hex.c
blob: 3fa0e699fa553c49c0d5e07d1b50726cce532b8b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * Copyright (C) 2004, 2005, 2007, 2008  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: hex.c,v 1.20 2008/09/25 04:02:39 tbox Exp $ */

/*! \file */

#include <config.h>

#include <ctype.h>

#include <isc/buffer.h>
#include <isc/hex.h>
#include <isc/lex.h>
#include <isc/string.h>
#include <isc/util.h>

#define RETERR(x) do { \
	isc_result_t _r = (x); \
	if (_r != ISC_R_SUCCESS) \
		return (_r); \
	} while (0)


/*
 * BEW: These static functions are copied from lib/dns/rdata.c.
 */
static isc_result_t
str_totext(const char *source, isc_buffer_t *target);

static isc_result_t
mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);

static const char hex[] = "0123456789ABCDEF";

isc_result_t
isc_hex_totext(isc_region_t *source, int wordlength,
	       const char *wordbreak, isc_buffer_t *target)
{
	char buf[3];
	unsigned int loops = 0;

	if (wordlength < 2)
		wordlength = 2;

	memset(buf, 0, sizeof(buf));
	while (source->length > 0) {
		buf[0] = hex[(source->base[0] >> 4) & 0xf];
		buf[1] = hex[(source->base[0]) & 0xf];
		RETERR(str_totext(buf, target));
		isc_region_consume(source, 1);

		loops++;
		if (source->length != 0 &&
		    (int)((loops + 1) * 2) >= wordlength)
		{
			loops = 0;
			RETERR(str_totext(wordbreak, target));
		}
	}
	return (ISC_R_SUCCESS);
}

/*%
 * State of a hex decoding process in progress.
 */
typedef struct {
	int length;		/*%< Desired length of binary data or -1 */
	isc_buffer_t *target;	/*%< Buffer for resulting binary data */
	int digits;		/*%< Number of buffered hex digits */
	int val[2];
} hex_decode_ctx_t;

static inline void
hex_decode_init(hex_decode_ctx_t *ctx, int length, isc_buffer_t *target)
{
	ctx->digits = 0;
	ctx->length = length;
	ctx->target = target;
}

static inline isc_result_t
hex_decode_char(hex_decode_ctx_t *ctx, int c) {
	char *s;

	if ((s = strchr(hex, toupper(c))) == NULL)
		return (ISC_R_BADHEX);
	ctx->val[ctx->digits++] = s - hex;
	if (ctx->digits == 2) {
		unsigned char num;

		num = (ctx->val[0] << 4) + (ctx->val[1]);
		RETERR(mem_tobuffer(ctx->target, &num, 1));
		if (ctx->length >= 0) {
			if (ctx->length == 0)
				return (ISC_R_BADHEX);
			else
				ctx->length -= 1;
		}
		ctx->digits = 0;
	}
	return (ISC_R_SUCCESS);
}

static inline isc_result_t
hex_decode_finish(hex_decode_ctx_t *ctx) {
	if (ctx->length > 0)
		return (ISC_R_UNEXPECTEDEND);
	if (ctx->digits != 0)
		return (ISC_R_BADHEX);
	return (ISC_R_SUCCESS);
}

isc_result_t
isc_hex_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
	hex_decode_ctx_t ctx;
	isc_textregion_t *tr;
	isc_token_t token;
	isc_boolean_t eol;

	hex_decode_init(&ctx, length, target);

	while (ctx.length != 0) {
		unsigned int i;

		if (length > 0)
			eol = ISC_FALSE;
		else
			eol = ISC_TRUE;
		RETERR(isc_lex_getmastertoken(lexer, &token,
					      isc_tokentype_string, eol));
		if (token.type != isc_tokentype_string)
			break;
		tr = &token.value.as_textregion;
		for (i = 0; i < tr->length; i++)
			RETERR(hex_decode_char(&ctx, tr->base[i]));
	}
	if (ctx.length < 0)
		isc_lex_ungettoken(lexer, &token);
	RETERR(hex_decode_finish(&ctx));
	return (ISC_R_SUCCESS);
}

isc_result_t
isc_hex_decodestring(const char *cstr, isc_buffer_t *target) {
	hex_decode_ctx_t ctx;

	hex_decode_init(&ctx, -1, target);
	for (;;) {
		int c = *cstr++;
		if (c == '\0')
			break;
		if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
			continue;
		RETERR(hex_decode_char(&ctx, c));
	}
	RETERR(hex_decode_finish(&ctx));
	return (ISC_R_SUCCESS);
}

static isc_result_t
str_totext(const char *source, isc_buffer_t *target) {
	unsigned int l;
	isc_region_t region;

	isc_buffer_availableregion(target, &region);
	l = strlen(source);

	if (l > region.length)
		return (ISC_R_NOSPACE);

	memcpy(region.base, source, l);
	isc_buffer_add(target, l);
	return (ISC_R_SUCCESS);
}

static isc_result_t
mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
	isc_region_t tr;

	isc_buffer_availableregion(target, &tr);
	if (length > tr.length)
		return (ISC_R_NOSPACE);
	memcpy(tr.base, base, length);
	isc_buffer_add(target, length);
	return (ISC_R_SUCCESS);
}