[dragonfly.git] / contrib / tcpdump / cpack.c

/*-
 * Copyright (c) 2003, 2004 David Young.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of David Young may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL DAVID
 * YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include <tcpdump-stdinc.h>

#include "cpack.h"
#include "extract.h"

static u_int8_t *
cpack_next_boundary(u_int8_t *buf, u_int8_t *p, size_t alignment)
{
	size_t misalignment = (size_t)(p - buf) % alignment;

	if (misalignment == 0)
		return p;

	return p + (alignment - misalignment);
}

/* Advance to the next wordsize boundary. Return NULL if fewer than
 * wordsize bytes remain in the buffer after the boundary.  Otherwise,
 * return a pointer to the boundary.
 */
static u_int8_t *
cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize)
{
	u_int8_t *next;

	/* Ensure alignment. */
	next = cpack_next_boundary(cs->c_buf, cs->c_next, wordsize);

	/* Too little space for wordsize bytes? */
	if (next - cs->c_buf + wordsize > cs->c_len)
		return NULL;

	return next;
}

int
cpack_init(struct cpack_state *cs, u_int8_t *buf, size_t buflen)
{
	memset(cs, 0, sizeof(*cs));

	cs->c_buf = buf;
	cs->c_len = buflen;
	cs->c_next = cs->c_buf;

	return 0;
}

/* Unpack a 64-bit unsigned integer. */
int
cpack_uint64(struct cpack_state *cs, u_int64_t *u)
{
	u_int8_t *next;

	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
		return -1;

	*u = EXTRACT_LE_64BITS(next);

	/* Move pointer past the u_int64_t. */
	cs->c_next = next + sizeof(*u);
	return 0;
}

/* Unpack a 32-bit unsigned integer. */
int
cpack_uint32(struct cpack_state *cs, u_int32_t *u)
{
	u_int8_t *next;

	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
		return -1;

	*u = EXTRACT_LE_32BITS(next);

	/* Move pointer past the u_int32_t. */
	cs->c_next = next + sizeof(*u);
	return 0;
}

/* Unpack a 16-bit unsigned integer. */
int
cpack_uint16(struct cpack_state *cs, u_int16_t *u)
{
	u_int8_t *next;

	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
		return -1;

	*u = EXTRACT_LE_16BITS(next);

	/* Move pointer past the u_int16_t. */
	cs->c_next = next + sizeof(*u);
	return 0;
}

/* Unpack an 8-bit unsigned integer. */
int
cpack_uint8(struct cpack_state *cs, u_int8_t *u)
{
	/* No space left? */
	if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len)
		return -1;

	*u = *cs->c_next;

	/* Move pointer past the u_int8_t. */
	cs->c_next++;
	return 0;
}
Commit	Line	Data
c8cf0f94 PA	1	/*-
	2	* Copyright (c) 2003, 2004 David Young. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	* 3. The name of David Young may not be used to endorse or promote
	13	* products derived from this software without specific prior
	14	* written permission.
	15	*
	16	* THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY
	17	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
	18	* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	19	* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVID
	20	* YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	21	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
	22	* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	24	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	25	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
	27	* OF SUCH DAMAGE.
	28	*/
	29
	30	#ifdef HAVE_CONFIG_H
	31	#include "config.h"
	32	#endif
	33
	34	#include <stdlib.h>
	35	#include <string.h>
	36	#include <tcpdump-stdinc.h>
	37
	38	#include "cpack.h"
	39	#include "extract.h"
	40
	41	static u_int8_t *
	42	cpack_next_boundary(u_int8_t buf, u_int8_t p, size_t alignment)
	43	{
	44	size_t misalignment = (size_t)(p - buf) % alignment;
	45
	46	if (misalignment == 0)
	47	return p;
	48
	49	return p + (alignment - misalignment);
	50	}
	51
	52	/* Advance to the next wordsize boundary. Return NULL if fewer than
	53	* wordsize bytes remain in the buffer after the boundary. Otherwise,
	54	* return a pointer to the boundary.
	55	*/
	56	static u_int8_t *
	57	cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize)
	58	{
	59	u_int8_t *next;
	60
	61	/* Ensure alignment. */
	62	next = cpack_next_boundary(cs->c_buf, cs->c_next, wordsize);
	63
	64	/* Too little space for wordsize bytes? */
65	if (next - cs->c_buf + wordsize > cs->c_len)
66	return NULL;
67
68	return next;
69	}
70
71	int
72	cpack_init(struct cpack_state cs, u_int8_t buf, size_t buflen)
73	{
74	memset(cs, 0, sizeof(*cs));
75
76	cs->c_buf = buf;
77	cs->c_len = buflen;
78	cs->c_next = cs->c_buf;
79
80	return 0;
81	}
82
83	/* Unpack a 64-bit unsigned integer. */
84	int
85	cpack_uint64(struct cpack_state cs, u_int64_t u)
86	{
87	u_int8_t *next;
88
89	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
90	return -1;
91
92	*u = EXTRACT_LE_64BITS(next);
93
94	/* Move pointer past the u_int64_t. */
95	cs->c_next = next + sizeof(*u);
96	return 0;
97	}
98
99	/* Unpack a 32-bit unsigned integer. */
100	int
101	cpack_uint32(struct cpack_state cs, u_int32_t u)
102	{
103	u_int8_t *next;
104
105	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
106	return -1;
107
108	*u = EXTRACT_LE_32BITS(next);
109
110	/* Move pointer past the u_int32_t. */
111	cs->c_next = next + sizeof(*u);
112	return 0;
113	}
114
115	/* Unpack a 16-bit unsigned integer. */
116	int
117	cpack_uint16(struct cpack_state cs, u_int16_t u)
118	{
119	u_int8_t *next;
120
121	if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
122	return -1;
123
124	*u = EXTRACT_LE_16BITS(next);
125
126	/* Move pointer past the u_int16_t. */
127	cs->c_next = next + sizeof(*u);
128	return 0;
129	}
130
131	/* Unpack an 8-bit unsigned integer. */
132	int
133	cpack_uint8(struct cpack_state cs, u_int8_t u)
134	{
135	/* No space left? */
136	if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len)
137	return -1;
138
139	u = cs->c_next;
140
141	/* Move pointer past the u_int8_t. */
142	cs->c_next++;
143	return 0;
144	}