Release 4.11 net/netfilter/nf_conntrack_h323_asn1.c

/****************************************************************************
 * ip_conntrack_helper_h323_asn1.c - BER and PER decoding library for H.323
 *                                   conntrack/NAT module.
 *
 * Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net>
 *
 * This source code is licensed under General Public License version 2.
 *
 * See ip_conntrack_helper_h323_asn1.h for details.
 *
 ****************************************************************************/

#ifdef __KERNEL__
#include <linux/kernel.h>
#else
#include <stdio.h>
#endif
#include <linux/netfilter/nf_conntrack_h323_asn1.h>

/* Trace Flag */
#ifndef H323_TRACE

#define H323_TRACE 0
#endif

#if H323_TRACE

#define TAB_SIZE 4

#define IFTHEN(cond, act) if(cond){act;}
#ifdef __KERNEL__

#define PRINT printk
#else

#define PRINT printf
#endif

#define FNAME(name) name,
#else

#define IFTHEN(cond, act)

#define PRINT(fmt, args...)

#define FNAME(name)
#endif

/* ASN.1 Types */

#define NUL 0

#define BOOL 1

#define OID 2

#define INT 3

#define ENUM 4

#define BITSTR 5

#define NUMSTR 6

#define NUMDGT 6

#define TBCDSTR 6

#define OCTSTR 7

#define PRTSTR 7

#define IA5STR 7

#define GENSTR 7

#define BMPSTR 8

#define SEQ 9

#define SET 9

#define SEQOF 10

#define SETOF 10

#define CHOICE 11

/* Constraint Types */

#define FIXD 0
/* #define BITS 1-8 */

#define BYTE 9

#define WORD 10

#define CONS 11

#define SEMI 12

#define UNCO 13

/* ASN.1 Type Attributes */

#define SKIP 0

#define STOP 1

#define DECODE 2

#define EXT 4

#define OPEN 8

#define OPT 16


/* ASN.1 Field Structure */

typedef struct field_t {
#if H323_TRACE
	
char *name;
#endif
	
unsigned char type;
	
unsigned char sz;
	
unsigned char lb;
	
unsigned char ub;
	
unsigned short attr;
	
unsigned short offset;
	
const struct field_t *fields;
} 
field_t;

/* Bit Stream */
typedef struct {
	
unsigned char *buf;
	
unsigned char *beg;
	
unsigned char *end;
	
unsigned char *cur;
	
unsigned int bit;
} 
bitstr_t;

/* Tool Functions */

#define INC_BIT(bs) if((++(bs)->bit)>7){(bs)->cur++;(bs)->bit=0;}

#define INC_BITS(bs,b) if(((bs)->bit+=(b))>7){(bs)->cur+=(bs)->bit>>3;(bs)->bit&=7;}

#define BYTE_ALIGN(bs) if((bs)->bit){(bs)->cur++;(bs)->bit=0;}

#define CHECK_BOUND(bs,n) if((bs)->cur+(n)>(bs)->end)return(H323_ERROR_BOUND)
static unsigned int get_len(bitstr_t *bs);
static unsigned int get_bit(bitstr_t *bs);
static unsigned int get_bits(bitstr_t *bs, unsigned int b);
static unsigned int get_bitmap(bitstr_t *bs, unsigned int b);
static unsigned int get_uint(bitstr_t *bs, int b);

/* Decoder Functions */
static int decode_nul(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_bool(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_oid(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_int(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_enum(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_bitstr(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_numstr(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_octstr(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_bmpstr(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_seq(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_seqof(bitstr_t *bs, const struct field_t *f, char *base, int level);
static int decode_choice(bitstr_t *bs, const struct field_t *f, char *base, int level);

/* Decoder Functions Vector */

typedef int (*decoder_t)(bitstr_t *, const struct field_t *, char *, int);

static const decoder_t Decoders[] = {
	decode_nul,
	decode_bool,
	decode_oid,
	decode_int,
	decode_enum,
	decode_bitstr,
	decode_numstr,
	decode_octstr,
	decode_bmpstr,
	decode_seq,
	decode_seqof,
	decode_choice,
};

/****************************************************************************
 * H.323 Types
 ****************************************************************************/
#include "nf_conntrack_h323_types.c"

/****************************************************************************
 * Functions
 ****************************************************************************/
/* Assume bs is aligned && v < 16384 */


static unsigned int get_len(bitstr_t *bs)
{
	unsigned int v;

	v = *bs->cur++;

	if (v & 0x80) {
		v &= 0x3f;
		v <<= 8;
		v += *bs->cur++;
	}

	return v;
}

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Jing Min Zhao
47
94.00%
1
33.33%
Jan Engelhardt
2
4.00%
1
33.33%
Stephen Hemminger
1
2.00%
1
33.33%
Total
50
100.00%
3
100.00%

/****************************************************************************/


static unsigned int get_bit(bitstr_t *bs)
{
	unsigned int b = (*bs->cur) & (0x80 >> bs->bit);

	INC_BIT(bs);

	return b;
}

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Jing Min Zhao
35
92.11%
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33.33%
Jan Engelhardt
2
5.26%
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33.33%
Stephen Hemminger
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2.63%
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33.33%
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/****************************************************************************/
/* Assume b <= 8 */


static unsigned int get_bits(bitstr_t *bs, unsigned int b)
{
	unsigned int v, l;

	v = (*bs->cur) & (0xffU >> bs->bit);
	l = b + bs->bit;

	if (l < 8) {
		v >>= 8 - l;
		bs->bit = l;
	} else if (l == 8) {
		bs->cur++;
		bs->bit = 0;
	} else {		/* l > 8 */

		v <<= 8;
		v += *(++bs->cur);
		v >>= 16 - l;
		bs->bit = l - 8;
	}

	return v;
}

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Jing Min Zhao
117
96.69%
1
33.33%
Jan Engelhardt
3
2.48%
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33.33%
Stephen Hemminger
1
0.83%
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33.33%
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/****************************************************************************/
/* Assume b <= 32 */


static unsigned int get_bitmap(bitstr_t *bs, unsigned int b)
{
	unsigned int v, l, shift, bytes;

	if (!b)
		return 0;

	l = bs->bit + b;

	if (l < 8) {
		v = (unsigned int)(*bs->cur) << (bs->bit + 24);
		bs->bit = l;
	} else if (l == 8) {
		v = (unsigned int)(*bs->cur++) << (bs->bit + 24);
		bs->bit = 0;
	} else {
		for (bytes = l >> 3, shift = 24, v = 0; bytes;
		     bytes--, shift -= 8)
			v |= (unsigned int)(*bs->cur++) << shift;

		if (l < 32) {
			v |= (unsigned int)(*bs->cur) << shift;
			v <<= bs->bit;
		} else if (l > 32) {
			v <<= bs->bit;
			v |= (*bs->cur) >> (8 - bs->bit);
		}

		bs->bit = l & 0x7;
	}

	v &= 0xffffffff << (32 - b);

	return v;
}

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Jing Min Zhao
231
96.65%
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33.33%
Jan Engelhardt
7
2.93%
1
33.33%
Stephen Hemminger
1
0.42%
1
33.33%
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100.00%
3
100.00%

/****************************************************************************
 * Assume bs is aligned and sizeof(unsigned int) == 4
 ****************************************************************************/


static unsigned int get_uint(bitstr_t *bs, int b)
{
	unsigned int v = 0;

	switch (b) {
	case 4:
		v |= *bs->cur++;
		v <<= 8;
	case 3:
		v |= *bs->cur++;
		v <<= 8;
	case 2:
		v |= *bs->cur++;
		v <<= 8;
	case 1:
		v |= *bs->cur++;
		break;
	}
	return v;
}

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CommitProp
Jing Min Zhao
83
96.51%
1
33.33%
Jan Engelhardt
2
2.33%
1
33.33%
Stephen Hemminger
1
1.16%
1
33.33%
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100.00%
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/****************************************************************************/


static int decode_nul(bitstr_t *bs, const struct field_t *f,
                      char *base, int level)
{
	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	return H323_ERROR_NONE;
}

Contributors
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CommitProp
Jing Min Zhao
38
92.68%
1
33.33%
Jan Engelhardt
2
4.88%
1
33.33%
Stephen Hemminger
1
2.44%
1
33.33%
Total
41
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/****************************************************************************/


static int decode_bool(bitstr_t *bs, const struct field_t *f,
                       char *base, int level)
{
	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	INC_BIT(bs);

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

Contributors
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CommitProp
Jing Min Zhao
50
94.34%
1
33.33%
Jan Engelhardt
2
3.77%
1
33.33%
Stephen Hemminger
1
1.89%
1
33.33%
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53
100.00%
3
100.00%

/****************************************************************************/


static int decode_oid(bitstr_t *bs, const struct field_t *f,
                      char *base, int level)
{
	int len;

	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	BYTE_ALIGN(bs);
	CHECK_BOUND(bs, 1);
	len = *bs->cur++;
	bs->cur += len;

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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Jing Min Zhao
74
96.10%
1
33.33%
Jan Engelhardt
2
2.60%
1
33.33%
Stephen Hemminger
1
1.30%
1
33.33%
Total
77
100.00%
3
100.00%

/****************************************************************************/


static int decode_int(bitstr_t *bs, const struct field_t *f,
                      char *base, int level)
{
	unsigned int len;

	PRINT("%*.s%s", level * TAB_SIZE, " ", f->name);

	switch (f->sz) {
	case BYTE:		/* Range == 256 */
		BYTE_ALIGN(bs);
		bs->cur++;
		break;
	case WORD:		/* 257 <= Range <= 64K */
		BYTE_ALIGN(bs);
		bs->cur += 2;
		break;
	case CONS:		/* 64K < Range < 4G */
		len = get_bits(bs, 2) + 1;
		BYTE_ALIGN(bs);
		if (base && (f->attr & DECODE)) {	/* timeToLive */
			unsigned int v = get_uint(bs, len) + f->lb;
			PRINT(" = %u", v);
			*((unsigned int *)(base + f->offset)) = v;
		}
		bs->cur += len;
		break;
	case UNCO:
		BYTE_ALIGN(bs);
		CHECK_BOUND(bs, 2);
		len = get_len(bs);
		bs->cur += len;
		break;
	default:		/* 2 <= Range <= 255 */
		INC_BITS(bs, f->sz);
		break;
	}

	PRINT("\n");

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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Jing Min Zhao
213
97.26%
1
25.00%
Jan Engelhardt
5
2.28%
2
50.00%
Stephen Hemminger
1
0.46%
1
25.00%
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4
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/****************************************************************************/


static int decode_enum(bitstr_t *bs, const struct field_t *f,
                       char *base, int level)
{
	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	if ((f->attr & EXT) && get_bit(bs)) {
		INC_BITS(bs, 7);
	} else {
		INC_BITS(bs, f->sz);
	}

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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81
96.43%
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33.33%
Jan Engelhardt
2
2.38%
1
33.33%
Stephen Hemminger
1
1.19%
1
33.33%
Total
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100.00%
3
100.00%

/****************************************************************************/


static int decode_bitstr(bitstr_t *bs, const struct field_t *f,
                         char *base, int level)
{
	unsigned int len;

	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	BYTE_ALIGN(bs);
	switch (f->sz) {
	case FIXD:		/* fixed length > 16 */
		len = f->lb;
		break;
	case WORD:		/* 2-byte length */
		CHECK_BOUND(bs, 2);
		len = (*bs->cur++) << 8;
		len += (*bs->cur++) + f->lb;
		break;
	case SEMI:
		CHECK_BOUND(bs, 2);
		len = get_len(bs);
		break;
	default:
		len = 0;
		break;
	}

	bs->cur += len >> 3;
	bs->bit = len & 7;

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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Jing Min Zhao
150
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25.00%
Jan Engelhardt
3
1.95%
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50.00%
Stephen Hemminger
1
0.65%
1
25.00%
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/****************************************************************************/


static int decode_numstr(bitstr_t *bs, const struct field_t *f,
                         char *base, int level)
{
	unsigned int len;

	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	/* 2 <= Range <= 255 */
	len = get_bits(bs, f->sz) + f->lb;

	BYTE_ALIGN(bs);
	INC_BITS(bs, (len << 2));

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

Contributors
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Jing Min Zhao
80
95.24%
1
25.00%
Jan Engelhardt
3
3.57%
2
50.00%
Stephen Hemminger
1
1.19%
1
25.00%
Total
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100.00%
4
100.00%

/****************************************************************************/


static int decode_octstr(bitstr_t *bs, const struct field_t *f,
                         char *base, int level)
{
	unsigned int len;

	PRINT("%*.s%s", level * TAB_SIZE, " ", f->name);

	switch (f->sz) {
	case FIXD:		/* Range == 1 */
		if (f->lb > 2) {
			BYTE_ALIGN(bs);
			if (base && (f->attr & DECODE)) {
				/* The IP Address */
				IFTHEN(f->lb == 4,
				       PRINT(" = %d.%d.%d.%d:%d",
					     bs->cur[0], bs->cur[1],
					     bs->cur[2], bs->cur[3],
					     bs->cur[4] * 256 + bs->cur[5]));
				*((unsigned int *)(base + f->offset)) =
				    bs->cur - bs->buf;
			}
		}
		len = f->lb;
		break;
	case BYTE:		/* Range == 256 */
		BYTE_ALIGN(bs);
		CHECK_BOUND(bs, 1);
		len = (*bs->cur++) + f->lb;
		break;
	case SEMI:
		BYTE_ALIGN(bs);
		CHECK_BOUND(bs, 2);
		len = get_len(bs) + f->lb;
		break;
	default:		/* 2 <= Range <= 255 */
		len = get_bits(bs, f->sz) + f->lb;
		BYTE_ALIGN(bs);
		break;
	}

	bs->cur += len;

	PRINT("\n");

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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0.36%
1
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/****************************************************************************/


static int decode_bmpstr(bitstr_t *bs, const struct field_t *f,
                         char *base, int level)
{
	unsigned int len;

	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	switch (f->sz) {
	case BYTE:		/* Range == 256 */
		BYTE_ALIGN(bs);
		CHECK_BOUND(bs, 1);
		len = (*bs->cur++) + f->lb;
		break;
	default:		/* 2 <= Range <= 255 */
		len = get_bits(bs, f->sz) + f->lb;
		BYTE_ALIGN(bs);
		break;
	}

	bs->cur += len << 1;

	CHECK_BOUND(bs, 0);
	return H323_ERROR_NONE;
}

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1
0.82%
1
25.00%
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100.00%
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100.00%

/****************************************************************************/


static int decode_seq(bitstr_t *bs, const struct field_t *f,
                      char *base, int level)
{
	unsigned int ext, bmp, i, opt, len = 0, bmp2, bmp2_len;
	int err;
	const struct field_t *son;
	unsigned char *beg = NULL;

	PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);

	/* Decode? */
	base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;

	/* Extensible? */
	ext = (f->attr & EXT) ? get_bit(bs) : 0;

	/* Get fields bitmap */
	bmp = get_bitmap(bs, f->sz);
	if (base)
		*(unsigned int *)base = bmp;

	/* Decode the root components */
	for (i = opt = 0, son = f->fields; i < f->lb; i++, son++) {
		if (son->attr & STOP) {
			PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
			      son->name);
			return H323_ERROR_STOP;
		}

		if (son->attr & OPT) {	/* Optional component */
			if (!((0x80000000U >> (opt++)) & bmp))	/* Not exist */
				continue;
		}

		/* Decode */
		if (son->attr & OPEN) {	/* Open field */
			CHECK_BOUND(bs, 2);
			len = get_len(bs);
			CHECK_BOUND(bs, len);
			if (!base || !(son->attr & DECODE)) {
				PRINT("%*.s%s\n", (level + 1) * TAB_SIZE,
				      " ", son->name);
				bs->cur += len;
				continue;
			}
			beg = bs->cur;

			/* Decode */
			if ((err = (Decoders[son->type]) (bs, son, base,
							  level + 1)) <
			    H323_ERROR_NONE)
				return err;

			bs->cur = beg + len;
			bs->bit = 0;
		} else if ((err = (Decoders[son->type]) (bs, son, base,
							 level + 1)) <
			   H323_ERROR_NONE)
			return err;
	}

	/* No extension? */
	if (!ext)
		return H323_ERROR_NONE;

	/* Get the extension bitmap */
	bmp2_len = get_bits(bs, 7) + 1;
	CHECK_BOUND(bs, (bmp2_len + 7) >> 3);
	bmp2 = get_bitmap(bs, bmp2_len);
	bmp |= bmp2 >> f->sz;
	if (base)
		*(unsigned int *)base = bmp;
	BYTE_ALIGN(bs);

	/* Decode the extension components */
	for (opt = 0; opt < bmp2_len; opt++, i++, son++) {
		/* Check Range */
		if (i >= f->ub) {	/* Newer Version? */
			CHECK_BOUND(bs, 2);
			len = get_len(bs);
			CHECK_BOUND(bs, len);
			bs->cur += len;
			continue;
		}

		if (son->attr & STOP) {
			PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
			      son->name);
			return H323_ERROR_STOP;
		}

		if (!((0x80000000 >> opt) & bmp2))	/* Not present */
			continue;

		CHECK_BOUND(bs, 2);
		len = get_len(bs);
		CHECK_BOUND(bs, len);
		if (!base || !(son->attr & DECODE)) {
			PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
			      son->name);
			bs->cur += len;
			continue;
		}
		beg = bs->cur;

		if ((err = (Decoders[son->type])