/* $OpenBSD: field.c,v 1.16 2004/06/14 09:55:41 ho Exp $	 */
/* $EOM: field.c,v 1.11 2000/02/20 19:58:37 niklas Exp $	 */

/*
 * Copyright (c) 1998, 1999 Niklas Hallqvist.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "sysdep.h"

#include "constants.h"
#include "field.h"
#include "log.h"
#include "util.h"

static char    *field_debug_raw(u_int8_t *, size_t, struct constant_map **);
static char    *field_debug_num(u_int8_t *, size_t, struct constant_map **);
static char    *field_debug_mask(u_int8_t *, size_t, struct constant_map **);
static char    *field_debug_ign(u_int8_t *, size_t, struct constant_map **);
static char    *field_debug_cst(u_int8_t *, size_t, struct constant_map **);

/* Contents must match the enum in struct field.  */
static char    *(*decode_field[]) (u_int8_t *, size_t,
    struct constant_map **) = {
	field_debug_raw,
	field_debug_num,
	field_debug_mask,
	field_debug_ign,
	field_debug_cst
};

/*
 * Return a string showing the hexadecimal contents of the LEN-sized buffer
 * BUF.  MAPS should be zero and is only here because the API requires it.
 */
static char *
field_debug_raw(u_int8_t *buf, size_t len, struct constant_map **maps)
{
	char	*retval, *p;

	if (len == 0)
		return 0;
	retval = malloc(3 + len * 2);
	if (!retval)
		return 0;
	strlcpy(retval, "0x", 3 + len * 2);
	p = retval + 2;
	for (; len > 0; len--) {
		snprintf(p, 1 + len * 2, "%02x", *buf++);
		p += 2;
	}
	return retval;
}

/*
 * Convert the unsigned LEN-sized number at BUF of network byteorder to a
 * 32-bit unsigned integer of host byteorder pointed to by VAL.
 */
static int
extract_val(u_int8_t *buf, size_t len, u_int32_t *val)
{
	switch (len) {
	case 1:
		*val = *buf;
		break;
	case 2:
		*val = decode_16(buf);
		break;
	case 4:
		*val = decode_32(buf);
		break;
	default:
		return -1;
	}
	return 0;
}

/*
 * Return a textual representation of the unsigned number pointed to by BUF
 * which is LEN octets long.  MAPS should be zero and is only here because
 * the API requires it.
 */
static char *
field_debug_num(u_int8_t *buf, size_t len, struct constant_map **maps)
{
	char           *retval;
	u_int32_t       val;

	if (extract_val(buf, len, &val))
		return 0;
	/* 3 decimal digits are enough to represent each byte.  */
	retval = malloc(3 * len);
	snprintf(retval, 3 * len, "%u", val);
	return retval;
}

/*
 * Return the symbolic names of the flags pointed to by BUF which is LEN
 * octets long, using the constant maps MAPS.
 */
static char *
field_debug_mask(u_int8_t *buf, size_t len, struct constant_map **maps)
{
	u_int32_t       val;
	u_int32_t       bit;
	char           *retval, *new_buf, *name;
	size_t          buf_sz;

	if (extract_val(buf, len, &val))
		return 0;

	/* Size for brackets, two spaces and a NUL terminator.  */
	buf_sz = 4;
	retval = malloc(buf_sz);
	if (!retval)
		return 0;

	strlcpy(retval, "[ ", buf_sz);
	for (bit = 1; bit; bit <<= 1) {
		if (val & bit) {
			name = constant_name_maps(maps, bit);
			buf_sz += strlen(name) + 1;
			new_buf = realloc(retval, buf_sz);
			if (!new_buf) {
				free(retval);
				return 0;
			}
			retval = new_buf;
			strlcat(retval, name, buf_sz);
			strlcat(retval, " ", buf_sz);
		}
	}
	strlcat(retval, "]", buf_sz);
	return retval;
}

/*
 * Just a dummy needed to skip the unused LEN sized space at BUF.  MAPS
 * should be zero and is only here because the API requires it.
 */
static char *
field_debug_ign(u_int8_t *buf, size_t len, struct constant_map **maps)
{
	return 0;
}

/*
 * Return the symbolic name of a constant pointed to by BUF which is LEN
 * octets long, using the constant maps MAPS.
 */
static char *
field_debug_cst(u_int8_t *buf, size_t len, struct constant_map **maps)
{
	u_int32_t       val;

	if (extract_val(buf, len, &val))
		return 0;

	return strdup(constant_name_maps(maps, val));
}

/* Pretty-print a field from BUF as described by F.  */
void
field_dump_field(struct field *f, u_int8_t *buf)
{
	char	*value;

	value = decode_field[(int) f->type] (buf + f->offset, f->len, f->maps);
	if (value) {
		LOG_DBG((LOG_MESSAGE, 70, "%s: %s", f->name, value));
		free(value);
	}
}

/* Pretty-print all the fields of BUF as described in FIELDS.  */
void
field_dump_payload(struct field *fields, u_int8_t *buf)
{
	struct field   *field;

	for (field = fields; field->name; field++)
		field_dump_field(field, buf);
}

/* Return the numeric value of the field F of BUF.  */
u_int32_t
field_get_num(struct field *f, u_int8_t *buf)
{
	u_int32_t       val;

	if (extract_val(buf + f->offset, f->len, &val))
		return 0;
	return val;
}

/* Stash the number VAL into BUF's field F.  */
void
field_set_num(struct field *f, u_int8_t *buf, u_int32_t val)
{
	switch (f->len) {
	case 1:
		buf[f->offset] = val;
		break;
	case 2:
		encode_16(buf + f->offset, val);
		break;
	case 4:
		encode_32(buf + f->offset, val);
		break;
	}
}

/* Stash BUF's raw field F into VAL.  */
void
field_get_raw(struct field *f, u_int8_t *buf, u_int8_t *val)
{
	memcpy(val, buf + f->offset, f->len);
}

/* Stash the buffer VAL into BUF's field F.  */
void
field_set_raw(struct field *f, u_int8_t *buf, u_int8_t *val)
{
	memcpy(buf + f->offset, val, f->len);
}