libs/smux/asn_codecs_prim.c

   1 /*-
   2  * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
   3  * Redistribution and modifications are permitted subject to BSD license.
   4  */
   5 #include <asn_internal.h>
   6 #include <asn_codecs_prim.h>
   7 #include <errno.h>
   8
   9 /*
  10  * Decode an always-primitive type.
  11  */
  12 asn_dec_rval_t
  13 ber_decode_primitive(asn_codec_ctx_t *opt_codec_ctx,
  14         asn_TYPE_descriptor_t *td,
  15         void **sptr, const void *buf_ptr, size_t size, int tag_mode) {
  16         ASN__PRIMITIVE_TYPE_t *st = (ASN__PRIMITIVE_TYPE_t *)*sptr;
  17         asn_dec_rval_t rval;
  18         ber_tlv_len_t length = 0; /* =0 to avoid [incorrect] warning. */
  19
  20         /*
  21          * If the structure is not there, allocate it.
  22          */
  23         if(st == NULL) {
  24                 st = (ASN__PRIMITIVE_TYPE_t *)CALLOC(1, sizeof(*st));
  25                 if(st == NULL) ASN__DECODE_FAILED;
  26                 *sptr = (void *)st;
  27         }
  28
  29         ASN_DEBUG("Decoding %s as plain primitive (tm=%d)",
  30                 td->name, tag_mode);
  31
  32         /*
  33          * Check tags and extract value length.
  34          */
  35         rval = ber_check_tags(opt_codec_ctx, td, 0, buf_ptr, size,
  36                         tag_mode, 0, &length, 0);
  37         if(rval.code != RC_OK)
  38                 return rval;
  39
  40         ASN_DEBUG("%s length is %d bytes", td->name, (int)length);
  41
  42         /*
  43          * Make sure we have this length.
  44          */
  45         buf_ptr = ((const char *)buf_ptr) + rval.consumed;
  46         size -= rval.consumed;
  47         if(length > (ber_tlv_len_t)size) {
  48                 rval.code = RC_WMORE;
  49                 rval.consumed = 0;
  50                 return rval;
  51         }
  52
  53         st->size = (int)length;
  54         /* The following better be optimized away. */
  55         if(sizeof(st->size) != sizeof(length)
  56                         && (ber_tlv_len_t)st->size != length) {
  57                 st->size = 0;
  58                 ASN__DECODE_FAILED;
  59         }
  60
  61         st->buf = (uint8_t *)MALLOC(length + 1);
  62         if(!st->buf) {
  63                 st->size = 0;
  64                 ASN__DECODE_FAILED;
  65         }
  66
  67         memcpy(st->buf, buf_ptr, length);
  68         st->buf[length] = '\0';         /* Just in case */
  69
  70         rval.code = RC_OK;
  71         rval.consumed += length;
  72
  73         ASN_DEBUG("Took %ld/%ld bytes to encode %s",
  74                 (long)rval.consumed,
  75                 (long)length, td->name);
  76
  77         return rval;
  78 }
  79
  80 /*
  81  * Encode an always-primitive type using DER.
  82  */
  83 asn_enc_rval_t
  84 der_encode_primitive(asn_TYPE_descriptor_t *td, void *sptr,
  85         int tag_mode, ber_tlv_tag_t tag,
  86         asn_app_consume_bytes_f *cb, void *app_key) {
  87         asn_enc_rval_t erval;
  88         ASN__PRIMITIVE_TYPE_t *st = (ASN__PRIMITIVE_TYPE_t *)sptr;
  89
  90         ASN_DEBUG("%s %s as a primitive type (tm=%d)",
  91                 cb?"Encoding":"Estimating", td->name, tag_mode);
  92
  93         erval.encoded = der_write_tags(td, st->size, tag_mode, 0, tag,
  94                 cb, app_key);
  95         ASN_DEBUG("%s wrote tags %d", td->name, (int)erval.encoded);
  96         if(erval.encoded == -1) {
  97                 erval.failed_type = td;
  98                 erval.structure_ptr = sptr;
  99                 return erval;
 100         }
 101
 102         if(cb && st->buf) {
 103                 if(cb(st->buf, st->size, app_key) < 0) {
 104                         erval.encoded = -1;
 105                         erval.failed_type = td;
 106                         erval.structure_ptr = sptr;
 107                         return erval;
 108                 }
 109         } else {
 110                 assert(st->buf || st->size == 0);
 111         }
 112
 113         erval.encoded += st->size;
 114         ASN__ENCODED_OK(erval);
 115 }
 116
 117 void
 118 ASN__PRIMITIVE_TYPE_free(asn_TYPE_descriptor_t *td, void *sptr,
 119                 int contents_only) {
 120         ASN__PRIMITIVE_TYPE_t *st = (ASN__PRIMITIVE_TYPE_t *)sptr;
 121
 122         if(!td || !sptr)
 123                 return;
 124
 125         ASN_DEBUG("Freeing %s as a primitive type", td->name);
 126
 127         if(st->buf)
 128                 FREEMEM(st->buf);
 129
 130         if(!contents_only)
 131                 FREEMEM(st);
 132 }
 133
 134
 135 /*
 136  * Local internal type passed around as an argument.
 137  */
 138 struct xdp_arg_s {
 139         asn_TYPE_descriptor_t *type_descriptor;
 140         void *struct_key;
 141         xer_primitive_body_decoder_f *prim_body_decoder;
 142         int decoded_something;
 143         int want_more;
 144 };
 145
 146 /*
 147  * Since some kinds of primitive values can be encoded using value-specific
 148  * tags (<MINUS-INFINITY>, <enum-element>, etc), the primitive decoder must
 149  * be supplied with such tags to parse them as needed.
 150  */
 151 static int
 152 xer_decode__unexpected_tag(void *key, const void *chunk_buf, size_t chunk_size) {
 153         struct xdp_arg_s *arg = (struct xdp_arg_s *)key;
 154         enum xer_pbd_rval bret;
 155
 156         /*
 157          * The chunk_buf is guaranteed to start at '<'.
 158          */
 159         assert(chunk_size && ((const char *)chunk_buf)[0] == 0x3c);
 160
 161         /*
 162          * Decoding was performed once already. Prohibit doing it again.
 163          */
 164         if(arg->decoded_something)
 165                 return -1;
 166
 167         bret = arg->prim_body_decoder(arg->type_descriptor,
 168                 arg->struct_key, chunk_buf, chunk_size);
 169         switch(bret) {
 170         case XPBD_SYSTEM_FAILURE:
 171         case XPBD_DECODER_LIMIT:
 172         case XPBD_BROKEN_ENCODING:
 173                 break;
 174         case XPBD_BODY_CONSUMED:
 175                 /* Tag decoded successfully */
 176                 arg->decoded_something = 1;
 177                 /* Fall through */
 178         case XPBD_NOT_BODY_IGNORE:      /* Safe to proceed further */
 179                 return 0;
 180         }
 181
 182         return -1;
 183 }
 184
 185 static ssize_t
 186 xer_decode__primitive_body(void *key, const void *chunk_buf, size_t chunk_size, int have_more) {
 187         struct xdp_arg_s *arg = (struct xdp_arg_s *)key;
 188         enum xer_pbd_rval bret;
 189         size_t lead_wsp_size;
 190
 191         if(arg->decoded_something) {
 192                 if(xer_whitespace_span(chunk_buf, chunk_size) == chunk_size) {
 193                         /*
 194                          * Example:
 195                          * "<INTEGER>123<!--/--> </INTEGER>"
 196                          *                      ^- chunk_buf position.
 197                          */
 198                         return chunk_size;
 199                 }
 200                 /*
 201                  * Decoding was done once already. Prohibit doing it again.
 202                  */
 203                 return -1;
 204         }
 205
 206         if(!have_more) {
 207                 /*
 208                  * If we've received something like "1", we can't really
 209                  * tell whether it is really `1` or `123`, until we know
 210                  * that there is no more data coming.
 211                  * The have_more argument will be set to 1 once something
 212                  * like this is available to the caller of this callback:
 213                  * "1<tag_start..."
 214                  */
 215                 arg->want_more = 1;
 216                 return -1;
 217         }
 218
 219         lead_wsp_size = xer_whitespace_span(chunk_buf, chunk_size);
 220         chunk_buf = (const char *)chunk_buf + lead_wsp_size;
 221         chunk_size -= lead_wsp_size;
 222
 223         bret = arg->prim_body_decoder(arg->type_descriptor,
 224                 arg->struct_key, chunk_buf, chunk_size);
 225         switch(bret) {
 226         case XPBD_SYSTEM_FAILURE:
 227         case XPBD_DECODER_LIMIT:
 228         case XPBD_BROKEN_ENCODING:
 229                 break;
 230         case XPBD_BODY_CONSUMED:
 231                 /* Tag decoded successfully */
 232                 arg->decoded_something = 1;
 233                 /* Fall through */
 234         case XPBD_NOT_BODY_IGNORE:      /* Safe to proceed further */
 235                 return lead_wsp_size + chunk_size;
 236         }
 237
 238         return -1;
 239 }
 240
 241
 242 asn_dec_rval_t
 243 xer_decode_primitive(asn_codec_ctx_t *opt_codec_ctx,
 244         asn_TYPE_descriptor_t *td,
 245         void **sptr,
 246         size_t struct_size,
 247         const char *opt_mname,
 248         const void *buf_ptr, size_t size,
 249         xer_primitive_body_decoder_f *prim_body_decoder
 250 ) {
 251         const char *xml_tag = opt_mname ? opt_mname : td->xml_tag;
 252         asn_struct_ctx_t s_ctx;
 253         struct xdp_arg_s s_arg;
 254         asn_dec_rval_t rc;
 255
 256         /*
 257          * Create the structure if does not exist.
 258          */
 259         if(!*sptr) {
 260                 *sptr = CALLOC(1, struct_size);
 261                 if(!*sptr) ASN__DECODE_FAILED;
 262         }
 263
 264         memset(&s_ctx, 0, sizeof(s_ctx));
 265         s_arg.type_descriptor = td;
 266         s_arg.struct_key = *sptr;
 267         s_arg.prim_body_decoder = prim_body_decoder;
 268         s_arg.decoded_something = 0;
 269         s_arg.want_more = 0;
 270
 271         rc = xer_decode_general(opt_codec_ctx, &s_ctx, &s_arg,
 272                 xml_tag, buf_ptr, size,
 273                 xer_decode__unexpected_tag, xer_decode__primitive_body);
 274         switch(rc.code) {
 275         case RC_OK:
 276                 if(!s_arg.decoded_something) {
 277                         char ch;
 278                         ASN_DEBUG("Primitive body is not recognized, "
 279                                 "supplying empty one");
 280                         /*
 281                          * Decoding opportunity has come and gone.
 282                          * Where's the result?
 283                          * Try to feed with empty body, see if it eats it.
 284                          */
 285                         if(prim_body_decoder(s_arg.type_descriptor,
 286                                 s_arg.struct_key, &ch, 0)
 287                                         != XPBD_BODY_CONSUMED) {
 288                                 /*
 289                                  * This decoder does not like empty stuff.
 290                                  */
 291                                 ASN__DECODE_FAILED;
 292                         }
 293                 }
 294                 break;
 295         case RC_WMORE:
 296                 /*
 297                  * Redo the whole thing later.
 298                  * We don't have a context to save intermediate parsing state.
 299                  */
 300                 rc.consumed = 0;
 301                 break;
 302         case RC_FAIL:
 303                 rc.consumed = 0;
 304                 if(s_arg.want_more)
 305                         rc.code = RC_WMORE;
 306                 else
 307                         ASN__DECODE_FAILED;
 308                 break;
 309         }
 310         return rc;
 311 }
 312