cregit-Linux how code gets into the kernel

Release 4.8 net/netfilter/nf_conntrack_h323_asn1.c

Directory: net/netfilter
/****************************************************************************
 * 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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stephen hemmingerstephen hemminger12.00%133.33%
Total50100.00%3100.00%

/****************************************************************************/
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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stephen hemmingerstephen hemminger12.63%133.33%
Total38100.00%3100.00%

/****************************************************************************/ /* 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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Total121100.00%3100.00%

/****************************************************************************/ /* 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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Total239100.00%3100.00%

/**************************************************************************** * 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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stephen hemmingerstephen hemminger11.16%133.33%
Total86100.00%3100.00%

/****************************************************************************/
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; }

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stephen hemmingerstephen hemminger12.44%133.33%
Total41100.00%3100.00%

/****************************************************************************/
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; }

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stephen hemmingerstephen hemminger11.89%133.33%
Total53100.00%3100.00%

/****************************************************************************/
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 zhaojing min zhao7496.10%133.33%
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stephen hemmingerstephen hemminger11.30%133.33%
Total77100.00%3100.00%

/****************************************************************************/
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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Total219100.00%4100.00%

/****************************************************************************/
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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stephen hemmingerstephen hemminger11.19%133.33%
Total84100.00%3100.00%

/****************************************************************************/
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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stephen hemmingerstephen hemminger10.65%125.00%
Total154100.00%4100.00%

/****************************************************************************/
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; }

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stephen hemmingerstephen hemminger11.19%125.00%
Total84100.00%4100.00%

/****************************************************************************/
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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Total275100.00%4100.00%

/****************************************************************************/
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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jan engelhardtjan engelhardt32.46%250.00%
stephen hemmingerstephen hemminger10.82%125.00%
Total122100.00%4100.00%

/****************************************************************************/
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)