--- /dev/null
+/****************************************************************************
+ * 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;
+ struct field_t *fields;
+} field_t;
+
+/* Bit Stream */
+typedef struct {
+ unsigned char *buf;
+ unsigned char *beg;
+ unsigned char *end;
+ unsigned char *cur;
+ unsigned 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 get_len(bitstr_t * bs);
+static unsigned get_bit(bitstr_t * bs);
+static unsigned get_bits(bitstr_t * bs, unsigned b);
+static unsigned get_bitmap(bitstr_t * bs, unsigned b);
+static unsigned get_uint(bitstr_t * bs, int b);
+
+/* Decoder Functions */
+static int decode_nul(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_bool(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_oid(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_int(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_enum(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_bitstr(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_numstr(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_octstr(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_bmpstr(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_seq(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_seqof(bitstr_t * bs, field_t * f, char *base, int level);
+static int decode_choice(bitstr_t * bs, field_t * f, char *base, int level);
+
+/* Decoder Functions Vector */
+typedef int (*decoder_t) (bitstr_t *, field_t *, char *, int);
+static 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 */
+unsigned get_len(bitstr_t * bs)
+{
+ unsigned v;
+
+ v = *bs->cur++;
+
+ if (v & 0x80) {
+ v &= 0x3f;
+ v <<= 8;
+ v += *bs->cur++;
+ }
+
+ return v;
+}
+
+/****************************************************************************/
+unsigned get_bit(bitstr_t * bs)
+{
+ unsigned b = (*bs->cur) & (0x80 >> bs->bit);
+
+ INC_BIT(bs);
+
+ return b;
+}
+
+/****************************************************************************/
+/* Assume b <= 8 */
+unsigned get_bits(bitstr_t * bs, unsigned b)
+{
+ unsigned 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;
+}
+
+/****************************************************************************/
+/* Assume b <= 32 */
+unsigned get_bitmap(bitstr_t * bs, unsigned b)
+{
+ unsigned v, l, shift, bytes;
+
+ if (!b)
+ return 0;
+
+ l = bs->bit + b;
+
+ if (l < 8) {
+ v = (unsigned) (*bs->cur) << (bs->bit + 24);
+ bs->bit = l;
+ } else if (l == 8) {
+ v = (unsigned) (*bs->cur++) << (bs->bit + 24);
+ bs->bit = 0;
+ } else {
+ for (bytes = l >> 3, shift = 24, v = 0; bytes;
+ bytes--, shift -= 8)
+ v |= (unsigned) (*bs->cur++) << shift;
+
+ if (l < 32) {
+ v |= (unsigned) (*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;
+}
+
+/****************************************************************************
+ * Assume bs is aligned and sizeof(unsigned int) == 4
+ ****************************************************************************/
+unsigned get_uint(bitstr_t * bs, int b)
+{
+ unsigned 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;
+}
+
+/****************************************************************************/
+int decode_nul(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
+
+ return H323_ERROR_NONE;
+}
+
+/****************************************************************************/
+int decode_bool(bitstr_t * bs, 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;
+}
+
+/****************************************************************************/
+int decode_oid(bitstr_t * bs, 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;
+}
+
+/****************************************************************************/
+int decode_int(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned 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 v = get_uint(bs, len) + f->lb;
+ PRINT(" = %u", v);
+ *((unsigned *) (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;
+}
+
+/****************************************************************************/
+int decode_enum(bitstr_t * bs, 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;
+}
+
+/****************************************************************************/
+int decode_bitstr(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned 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;
+}
+
+/****************************************************************************/
+int decode_numstr(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned 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;
+}
+
+/****************************************************************************/
+int decode_octstr(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned 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 *) (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;
+}
+
+/****************************************************************************/
+int decode_bmpstr(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned 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;
+}
+
+/****************************************************************************/
+int decode_seq(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned ext, bmp, i, opt, len = 0, bmp2, bmp2_len;
+ int err;
+ 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 *) 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) {
+ 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 *) base = bmp;
+ BYTE_ALIGN(bs);
+
+ /* Decode the extension components */
+ for (opt = 0; opt < bmp2_len; opt++, i++, son++) {
+ if (i < f->ub && 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 Range */
+ if (i >= f->ub) { /* Newer Version? */
+ CHECK_BOUND(bs, 2);
+ len = get_len(bs);
+ CHECK_BOUND(bs, len);
+ bs->cur += len;
+ 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]) (bs, son, base,
+ level + 1)) <
+ H323_ERROR_NONE)
+ return err;
+
+ bs->cur = beg + len;
+ bs->bit = 0;
+ }
+ return H323_ERROR_NONE;
+}
+
+/****************************************************************************/
+int decode_seqof(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned count, effective_count = 0, i, len = 0;
+ int err;
+ 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;
+
+ /* Decode item count */
+ switch (f->sz) {
+ case BYTE:
+ BYTE_ALIGN(bs);
+ CHECK_BOUND(bs, 1);
+ count = *bs->cur++;
+ break;
+ case WORD:
+ BYTE_ALIGN(bs);
+ CHECK_BOUND(bs, 2);
+ count = *bs->cur++;
+ count <<= 8;
+ count = *bs->cur++;
+ break;
+ case SEMI:
+ BYTE_ALIGN(bs);
+ CHECK_BOUND(bs, 2);
+ count = get_len(bs);
+ break;
+ default:
+ count = get_bits(bs, f->sz);
+ break;
+ }
+ count += f->lb;
+
+ /* Write Count */
+ if (base) {
+ effective_count = count > f->ub ? f->ub : count;
+ *(unsigned *) base = effective_count;
+ base += sizeof(unsigned);
+ }
+
+ /* Decode nested field */
+ son = f->fields;
+ if (base)
+ base -= son->offset;
+ for (i = 0; i < count; i++) {
+ if (son->attr & OPEN) {
+ BYTE_ALIGN(bs);
+ 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]) (bs, son,
+ i <
+ effective_count ?
+ base : NULL,
+ level + 1)) <
+ H323_ERROR_NONE)
+ return err;
+
+ bs->cur = beg + len;
+ bs->bit = 0;
+ } else
+ if ((err = (Decoders[son->type]) (bs, son,
+ i <
+ effective_count ?
+ base : NULL,
+ level + 1)) <
+ H323_ERROR_NONE)
+ return err;
+
+ if (base)
+ base += son->offset;
+ }
+
+ return H323_ERROR_NONE;
+}
+
+
+/****************************************************************************/
+int decode_choice(bitstr_t * bs, field_t * f, char *base, int level)
+{
+ unsigned type, ext, len = 0;
+ int err;
+ 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;
+
+ /* Decode the choice index number */
+ if ((f->attr & EXT) && get_bit(bs)) {
+ ext = 1;
+ type = get_bits(bs, 7) + f->lb;
+ } else {
+ ext = 0;
+ type = get_bits(bs, f->sz);
+ }
+
+ /* Write Type */
+ if (base)
+ *(unsigned *) base = type;
+
+ /* Check Range */
+ if (type >= f->ub) { /* Newer version? */
+ BYTE_ALIGN(bs);
+ len = get_len(bs);
+ CHECK_BOUND(bs, len);
+ bs->cur += len;
+ return H323_ERROR_NONE;
+ }
+
+ /* Transfer to son level */
+ son = &f->fields[type];
+ if (son->attr & STOP) {
+ PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", son->name);
+ return H323_ERROR_STOP;
+ }
+
+ if (ext || (son->attr & OPEN)) {
+ BYTE_ALIGN(bs);
+ 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;
+ return H323_ERROR_NONE;
+ }
+ beg = bs->cur;
+
+ 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;
+
+ return H323_ERROR_NONE;
+}
+
+/****************************************************************************/
+int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage * ras)
+{
+ static field_t ras_message = {
+ FNAME("RasMessage") CHOICE, 5, 24, 32, DECODE | EXT,
+ 0, _RasMessage
+ };
+ bitstr_t bs;
+
+ bs.buf = bs.beg = bs.cur = buf;
+ bs.end = buf + sz;
+ bs.bit = 0;
+
+ return decode_choice(&bs, &ras_message, (char *) ras, 0);
+}
+
+/****************************************************************************/
+static int DecodeH323_UserInformation(unsigned char *buf, unsigned char *beg,
+ size_t sz, H323_UserInformation * uuie)
+{
+ static field_t h323_userinformation = {
+ FNAME("H323-UserInformation") SEQ, 1, 2, 2, DECODE | EXT,
+ 0, _H323_UserInformation
+ };
+ bitstr_t bs;
+
+ bs.buf = buf;
+ bs.beg = bs.cur = beg;
+ bs.end = beg + sz;
+ bs.bit = 0;
+
+ return decode_seq(&bs, &h323_userinformation, (char *) uuie, 0);
+}
+
+/****************************************************************************/
+int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz,
+ MultimediaSystemControlMessage *
+ mscm)
+{
+ static field_t multimediasystemcontrolmessage = {
+ FNAME("MultimediaSystemControlMessage") CHOICE, 2, 4, 4,
+ DECODE | EXT, 0, _MultimediaSystemControlMessage
+ };
+ bitstr_t bs;
+
+ bs.buf = bs.beg = bs.cur = buf;
+ bs.end = buf + sz;
+ bs.bit = 0;
+
+ return decode_choice(&bs, &multimediasystemcontrolmessage,
+ (char *) mscm, 0);
+}
+
+/****************************************************************************/
+int DecodeQ931(unsigned char *buf, size_t sz, Q931 * q931)
+{
+ unsigned char *p = buf;
+ int len;
+
+ if (!p || sz < 1)
+ return H323_ERROR_BOUND;
+
+ /* Protocol Discriminator */
+ if (*p != 0x08) {
+ PRINT("Unknown Protocol Discriminator\n");
+ return H323_ERROR_RANGE;
+ }
+ p++;
+ sz--;
+
+ /* CallReferenceValue */
+ if (sz < 1)
+ return H323_ERROR_BOUND;
+ len = *p++;
+ sz--;
+ if (sz < len)
+ return H323_ERROR_BOUND;
+ p += len;
+ sz -= len;
+
+ /* Message Type */
+ if (sz < 1)
+ return H323_ERROR_BOUND;
+ q931->MessageType = *p++;
+ PRINT("MessageType = %02X\n", q931->MessageType);
+ if (*p & 0x80) {
+ p++;
+ sz--;
+ }
+
+ /* Decode Information Elements */
+ while (sz > 0) {
+ if (*p == 0x7e) { /* UserUserIE */
+ if (sz < 3)
+ break;
+ p++;
+ len = *p++ << 8;
+ len |= *p++;
+ sz -= 3;
+ if (sz < len)
+ break;
+ p++;
+ len--;
+ return DecodeH323_UserInformation(buf, p, len,
+ &q931->UUIE);
+ }
+ p++;
+ sz--;
+ if (sz < 1)
+ break;
+ len = *p++;
+ if (sz < len)
+ break;
+ p += len;
+ sz -= len;
+ }
+
+ PRINT("Q.931 UUIE not found\n");
+
+ return H323_ERROR_BOUND;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff