X-Git-Url: https://gerrit.o-ran-sc.org/r/gitweb?p=sim%2Fe2-interface.git;a=blobdiff_plain;f=e2sim%2Fasn1c%2Fconstr_SEQUENCE_ber.c;fp=e2sim%2Fasn1c%2Fconstr_SEQUENCE_ber.c;h=e982172d33aea56302daa85ebe0db32af55fce68;hp=0000000000000000000000000000000000000000;hb=f5900596513e4359fc839ba361da085674e90b68;hpb=215d350dbe06a4c7ee370815f26128a7f7e160cb diff --git a/e2sim/asn1c/constr_SEQUENCE_ber.c b/e2sim/asn1c/constr_SEQUENCE_ber.c new file mode 100644 index 0000000..e982172 --- /dev/null +++ b/e2sim/asn1c/constr_SEQUENCE_ber.c @@ -0,0 +1,612 @@ +/* + * Copyright (c) 2017 Lev Walkin . + * All rights reserved. + * Redistribution and modifications are permitted subject to BSD license. + */ +#include +#include +#include + +/* + * Number of bytes left for this structure. + * (ctx->left) indicates the number of bytes _transferred_ for the structure. + * (size) contains the number of bytes in the buffer passed. + */ +#define LEFT ((size<(size_t)ctx->left)?size:(size_t)ctx->left) + +/* + * If the subprocessor function returns with an indication that it wants + * more data, it may well be a fatal decoding problem, because the + * size is constrained by the 's L, even if the buffer size allows + * reading more data. + * For example, consider the buffer containing the following TLVs: + * ... + * The TLV length clearly indicates that one byte is expected in V, but + * if the V processor returns with "want more data" even if the buffer + * contains way more data than the V processor have seen. + */ +#define SIZE_VIOLATION (ctx->left >= 0 && (size_t)ctx->left <= size) + +/* + * This macro "eats" the part of the buffer which is definitely "consumed", + * i.e. was correctly converted into local representation or rightfully skipped. + */ +#undef ADVANCE +#define ADVANCE(num_bytes) \ + do { \ + size_t num = num_bytes; \ + ptr = ((const char *)ptr) + num; \ + size -= num; \ + if(ctx->left >= 0) \ + ctx->left -= num; \ + consumed_myself += num; \ + } while(0) + +/* + * Switch to the next phase of parsing. + */ +#undef NEXT_PHASE +#define NEXT_PHASE(ctx) \ + do { \ + ctx->phase++; \ + ctx->step = 0; \ + } while(0) +#undef PHASE_OUT +#define PHASE_OUT(ctx) \ + do { \ + ctx->phase = 10; \ + } while(0) + +/* + * Return a standardized complex structure. + */ +#undef RETURN +#define RETURN(_code) \ + do { \ + rval.code = _code; \ + rval.consumed = consumed_myself; \ + return rval; \ + } while(0) + +/* + * Check whether we are inside the extensions group. + */ +#define IN_EXTENSION_GROUP(specs, memb_idx) \ + ((specs)->first_extension >= 0 \ + && (unsigned)(specs)->first_extension <= (memb_idx)) + +/* + * Tags are canonically sorted in the tag2element map. + */ +static int +_t2e_cmp(const void *ap, const void *bp) { + const asn_TYPE_tag2member_t *a = (const asn_TYPE_tag2member_t *)ap; + const asn_TYPE_tag2member_t *b = (const asn_TYPE_tag2member_t *)bp; + + int a_class = BER_TAG_CLASS(a->el_tag); + int b_class = BER_TAG_CLASS(b->el_tag); + + if(a_class == b_class) { + ber_tlv_tag_t a_value = BER_TAG_VALUE(a->el_tag); + ber_tlv_tag_t b_value = BER_TAG_VALUE(b->el_tag); + + if(a_value == b_value) { + if(a->el_no > b->el_no) + return 1; + /* + * Important: we do not check + * for a->el_no <= b->el_no! + */ + return 0; + } else if(a_value < b_value) + return -1; + else + return 1; + } else if(a_class < b_class) { + return -1; + } else { + return 1; + } +} + +/* + * The decoder of the SEQUENCE type. + */ +asn_dec_rval_t +SEQUENCE_decode_ber(const asn_codec_ctx_t *opt_codec_ctx, + const asn_TYPE_descriptor_t *td, void **struct_ptr, + const void *ptr, size_t size, int tag_mode) { + /* + * Bring closer parts of structure description. + */ + const asn_SEQUENCE_specifics_t *specs = (const asn_SEQUENCE_specifics_t *)td->specifics; + const asn_TYPE_member_t *elements = td->elements; + + /* + * Parts of the structure being constructed. + */ + void *st = *struct_ptr; /* Target structure. */ + asn_struct_ctx_t *ctx; /* Decoder context */ + + ber_tlv_tag_t tlv_tag; /* T from TLV */ + asn_dec_rval_t rval; /* Return code from subparsers */ + + ssize_t consumed_myself = 0; /* Consumed bytes from ptr */ + size_t edx; /* SEQUENCE element's index */ + + ASN_DEBUG("Decoding %s as SEQUENCE", td->name); + + /* + * Create the target structure if it is not present already. + */ + if(st == 0) { + st = *struct_ptr = CALLOC(1, specs->struct_size); + if(st == 0) { + RETURN(RC_FAIL); + } + } + + /* + * Restore parsing context. + */ + ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset); + + /* + * Start to parse where left previously + */ + switch(ctx->phase) { + case 0: + /* + * PHASE 0. + * Check that the set of tags associated with given structure + * perfectly fits our expectations. + */ + + rval = ber_check_tags(opt_codec_ctx, td, ctx, ptr, size, + tag_mode, 1, &ctx->left, 0); + if(rval.code != RC_OK) { + ASN_DEBUG("%s tagging check failed: %d", + td->name, rval.code); + return rval; + } + + if(ctx->left >= 0) + ctx->left += rval.consumed; /* ?Subtracted below! */ + ADVANCE(rval.consumed); + + NEXT_PHASE(ctx); + + ASN_DEBUG("Structure consumes %ld bytes, buffer %ld", + (long)ctx->left, (long)size); + + /* Fall through */ + case 1: + /* + * PHASE 1. + * From the place where we've left it previously, + * try to decode the next member from the list of + * this structure's elements. + * (ctx->step) stores the member being processed + * between invocations and the microphase {0,1} of parsing + * that member: + * step = ( * 2 + ). + */ + for(edx = ((size_t)ctx->step >> 1); edx < td->elements_count; + edx++, ctx->step = (ctx->step & ~1) + 2) { + void *memb_ptr; /* Pointer to the member */ + void **memb_ptr2; /* Pointer to that pointer */ + ssize_t tag_len; /* Length of TLV's T */ + size_t opt_edx_end; /* Next non-optional element */ + size_t n; + int use_bsearch; + + if(ctx->step & 1) + goto microphase2; + + /* + * MICROPHASE 1: Synchronize decoding. + */ + ASN_DEBUG("In %s SEQUENCE left %d, edx=%" ASN_PRI_SIZE " flags=%d" + " opt=%d ec=%d", + td->name, (int)ctx->left, edx, + elements[edx].flags, elements[edx].optional, + td->elements_count); + + if(ctx->left == 0 /* No more stuff is expected */ + && ( + /* Explicit OPTIONAL specification reaches the end */ + (edx + elements[edx].optional == td->elements_count) || + /* All extensions are optional */ + IN_EXTENSION_GROUP(specs, edx))) { + ASN_DEBUG("End of SEQUENCE %s", td->name); + /* + * Found the legitimate end of the structure. + */ + PHASE_OUT(ctx); + RETURN(RC_OK); + } + + /* + * Fetch the T from TLV. + */ + tag_len = ber_fetch_tag(ptr, LEFT, &tlv_tag); + ASN_DEBUG("Current tag in %s SEQUENCE for element %" ASN_PRI_SIZE " " + "(%s) is %s encoded in %d bytes, of frame %ld", + td->name, edx, elements[edx].name, + ber_tlv_tag_string(tlv_tag), (int)tag_len, (long)LEFT); + switch(tag_len) { + case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE); + /* Fall through */ + case -1: RETURN(RC_FAIL); + } + + if(ctx->left < 0 && ((const uint8_t *)ptr)[0] == 0) { + if(LEFT < 2) { + if(SIZE_VIOLATION) { + RETURN(RC_FAIL); + } else { + RETURN(RC_WMORE); + } + } else if(((const uint8_t *)ptr)[1] == 0) { + ASN_DEBUG("edx = %" ASN_PRI_SIZE ", opt = %d, ec=%d", edx, + elements[edx].optional, td->elements_count); + if((edx + elements[edx].optional == td->elements_count) + || IN_EXTENSION_GROUP(specs, edx)) { + /* + * Yeah, baby! Found the terminator + * of the indefinite length structure. + */ + /* + * Proceed to the canonical + * finalization function. + * No advancing is necessary. + */ + goto phase3; + } + } + } + + /* + * Find the next available type with this tag. + */ + use_bsearch = 0; + opt_edx_end = edx + elements[edx].optional + 1; + if(opt_edx_end > td->elements_count) + opt_edx_end = td->elements_count; /* Cap */ + else if(opt_edx_end - edx > 8) { + /* Limit the scope of linear search... */ + opt_edx_end = edx + 8; + use_bsearch = 1; + /* ... and resort to bsearch() */ + } + for(n = edx; n < opt_edx_end; n++) { + if(BER_TAGS_EQUAL(tlv_tag, elements[n].tag)) { + /* + * Found element corresponding to the tag + * being looked at. + * Reposition over the right element. + */ + edx = n; + ctx->step = 1 + 2 * edx; /* Remember! */ + goto microphase2; + } else if(elements[n].flags & ATF_ANY_TYPE) { + /* + * This is the ANY type, which may bear + * any flag whatsoever. + */ + edx = n; + ctx->step = 1 + 2 * edx; /* Remember! */ + goto microphase2; + } else if(elements[n].tag == (ber_tlv_tag_t)-1) { + use_bsearch = 1; + break; + } + } + if(use_bsearch) { + /* + * Resort to a binary search over + * sorted array of tags. + */ + const asn_TYPE_tag2member_t *t2m; + asn_TYPE_tag2member_t key = {0, 0, 0, 0}; + key.el_tag = tlv_tag; + key.el_no = edx; + t2m = (const asn_TYPE_tag2member_t *)bsearch(&key, + specs->tag2el, specs->tag2el_count, + sizeof(specs->tag2el[0]), _t2e_cmp); + if(t2m) { + const asn_TYPE_tag2member_t *best = 0; + const asn_TYPE_tag2member_t *t2m_f, *t2m_l; + size_t edx_max = edx + elements[edx].optional; + /* + * Rewind to the first element with that tag, + * `cause bsearch() does not guarantee order. + */ + t2m_f = t2m + t2m->toff_first; + t2m_l = t2m + t2m->toff_last; + for(t2m = t2m_f; t2m <= t2m_l; t2m++) { + if(t2m->el_no > edx_max) break; + if(t2m->el_no < edx) continue; + best = t2m; + } + if(best) { + edx = best->el_no; + ctx->step = 1 + 2 * edx; + goto microphase2; + } + } + n = opt_edx_end; + } + if(n == opt_edx_end) { + /* + * If tag is unknown, it may be either + * an unknown (thus, incorrect) tag, + * or an extension (...), + * or an end of the indefinite-length structure. + */ + if(!IN_EXTENSION_GROUP(specs, + edx + elements[edx].optional)) { + ASN_DEBUG("Unexpected tag %s (at %" ASN_PRI_SIZE ")", + ber_tlv_tag_string(tlv_tag), edx); + ASN_DEBUG("Expected tag %s (%s)%s", + ber_tlv_tag_string(elements[edx].tag), + elements[edx].name, + elements[edx].optional ?" or alternatives":""); + RETURN(RC_FAIL); + } else { + /* Skip this tag */ + ssize_t skip; + edx += elements[edx].optional; + + ASN_DEBUG("Skipping unexpected %s (at %" ASN_PRI_SIZE ")", + ber_tlv_tag_string(tlv_tag), edx); + skip = ber_skip_length(opt_codec_ctx, + BER_TLV_CONSTRUCTED(ptr), + (const char *)ptr + tag_len, + LEFT - tag_len); + ASN_DEBUG("Skip length %d in %s", + (int)skip, td->name); + switch(skip) { + case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE); + /* Fall through */ + case -1: RETURN(RC_FAIL); + } + + ADVANCE(skip + tag_len); + ctx->step -= 2; + edx--; + continue; /* Try again with the next tag */ + } + } + + /* + * MICROPHASE 2: Invoke the member-specific decoder. + */ + ctx->step |= 1; /* Confirm entering next microphase */ + microphase2: + ASN_DEBUG("Inside SEQUENCE %s MF2", td->name); + + /* + * Compute the position of the member inside a structure, + * and also a type of containment (it may be contained + * as pointer or using inline inclusion). + */ + if(elements[edx].flags & ATF_POINTER) { + /* Member is a pointer to another structure */ + memb_ptr2 = (void **)((char *)st + elements[edx].memb_offset); + } else { + /* + * A pointer to a pointer + * holding the start of the structure + */ + memb_ptr = (char *)st + elements[edx].memb_offset; + memb_ptr2 = &memb_ptr; + } + /* + * Invoke the member fetch routine according to member's type + */ + if(elements[edx].flags & ATF_OPEN_TYPE) { + rval = OPEN_TYPE_ber_get(opt_codec_ctx, td, st, &elements[edx], ptr, LEFT); + } else { + rval = elements[edx].type->op->ber_decoder(opt_codec_ctx, + elements[edx].type, + memb_ptr2, ptr, LEFT, + elements[edx].tag_mode); + } + ASN_DEBUG("In %s SEQUENCE decoded %" ASN_PRI_SIZE " %s of %d " + "in %d bytes rval.code %d, size=%d", + td->name, edx, elements[edx].type->name, + (int)LEFT, (int)rval.consumed, rval.code, (int)size); + switch(rval.code) { + case RC_OK: + break; + case RC_WMORE: /* More data expected */ + if(!SIZE_VIOLATION) { + ADVANCE(rval.consumed); + RETURN(RC_WMORE); + } + ASN_DEBUG("Size violation (c->l=%ld <= s=%ld)", + (long)ctx->left, (long)size); + /* Fall through */ + case RC_FAIL: /* Fatal error */ + RETURN(RC_FAIL); + } /* switch(rval) */ + + ADVANCE(rval.consumed); + } /* for(all structure members) */ + + phase3: + ctx->phase = 3; + /* Fall through */ + case 3: /* 00 and other tags expected */ + case 4: /* only 00's expected */ + + ASN_DEBUG("SEQUENCE %s Leftover: %ld, size = %ld", + td->name, (long)ctx->left, (long)size); + + /* + * Skip everything until the end of the SEQUENCE. + */ + while(ctx->left) { + ssize_t tl, ll; + + tl = ber_fetch_tag(ptr, LEFT, &tlv_tag); + switch(tl) { + case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE); + /* Fall through */ + case -1: RETURN(RC_FAIL); + } + + /* + * If expected <0><0>... + */ + if(ctx->left < 0 && ((const uint8_t *)ptr)[0] == 0) { + if(LEFT < 2) { + if(SIZE_VIOLATION) + RETURN(RC_FAIL); + else + RETURN(RC_WMORE); + } else if(((const uint8_t *)ptr)[1] == 0) { + /* + * Correctly finished with <0><0>. + */ + ADVANCE(2); + ctx->left++; + ctx->phase = 4; + continue; + } + } + + if(!IN_EXTENSION_GROUP(specs, td->elements_count) + || ctx->phase == 4) { + ASN_DEBUG("Unexpected continuation " + "of a non-extensible type " + "%s (SEQUENCE): %s", + td->name, + ber_tlv_tag_string(tlv_tag)); + RETURN(RC_FAIL); + } + + ll = ber_skip_length(opt_codec_ctx, + BER_TLV_CONSTRUCTED(ptr), + (const char *)ptr + tl, LEFT - tl); + switch(ll) { + case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE); + /* Fall through */ + case -1: RETURN(RC_FAIL); + } + + ADVANCE(tl + ll); + } + + PHASE_OUT(ctx); + } + + RETURN(RC_OK); +} + + +/* + * The DER encoder of the SEQUENCE type. + */ +asn_enc_rval_t +SEQUENCE_encode_der(const asn_TYPE_descriptor_t *td, const void *sptr, + int tag_mode, ber_tlv_tag_t tag, + asn_app_consume_bytes_f *cb, void *app_key) { + size_t computed_size = 0; + asn_enc_rval_t erval = {0,0,0}; + ssize_t ret; + size_t edx; + + ASN_DEBUG("%s %s as SEQUENCE", + cb?"Encoding":"Estimating", td->name); + + /* + * Gather the length of the underlying members sequence. + */ + for(edx = 0; edx < td->elements_count; edx++) { + asn_TYPE_member_t *elm = &td->elements[edx]; + + const void *memb_ptr; /* Pointer to the member */ + const void *const *memb_ptr2; /* Pointer to that pointer */ + + if(elm->flags & ATF_POINTER) { + memb_ptr2 = + (const void *const *)((const char *)sptr + elm->memb_offset); + if(!*memb_ptr2) { + ASN_DEBUG("Element %s %" ASN_PRI_SIZE " not present", + elm->name, edx); + if(elm->optional) + continue; + /* Mandatory element is missing */ + ASN__ENCODE_FAILED; + } + } else { + memb_ptr = (const void *)((const char *)sptr + elm->memb_offset); + memb_ptr2 = &memb_ptr; + } + + /* Eliminate default values */ + if(elm->default_value_cmp && elm->default_value_cmp(*memb_ptr2) == 0) + continue; + + erval = elm->type->op->der_encoder(elm->type, *memb_ptr2, + elm->tag_mode, elm->tag, + 0, 0); + if(erval.encoded == -1) + return erval; + computed_size += erval.encoded; + ASN_DEBUG("Member %" ASN_PRI_SIZE " %s estimated %ld bytes", + edx, elm->name, (long)erval.encoded); + } + + /* + * Encode the TLV for the sequence itself. + */ + ret = der_write_tags(td, computed_size, tag_mode, 1, tag, cb, app_key); + ASN_DEBUG("Wrote tags: %ld (+%ld)", (long)ret, (long)computed_size); + if(ret == -1) + ASN__ENCODE_FAILED; + erval.encoded = computed_size + ret; + + if(!cb) ASN__ENCODED_OK(erval); + + /* + * Encode all members. + */ + for(edx = 0; edx < td->elements_count; edx++) { + asn_TYPE_member_t *elm = &td->elements[edx]; + asn_enc_rval_t tmperval = {0,0,0}; + const void *memb_ptr; /* Pointer to the member */ + const void *const *memb_ptr2; /* Pointer to that pointer */ + + if(elm->flags & ATF_POINTER) { + memb_ptr2 = + (const void *const *)((const char *)sptr + elm->memb_offset); + if(!*memb_ptr2) continue; + } else { + memb_ptr = (const void *)((const char *)sptr + elm->memb_offset); + memb_ptr2 = &memb_ptr; + } + + /* Eliminate default values */ + if(elm->default_value_cmp && elm->default_value_cmp(*memb_ptr2) == 0) + continue; + + tmperval = elm->type->op->der_encoder(elm->type, *memb_ptr2, + elm->tag_mode, elm->tag, cb, app_key); + if(tmperval.encoded == -1) + return tmperval; + computed_size -= tmperval.encoded; + ASN_DEBUG("Member %" ASN_PRI_SIZE " %s of SEQUENCE %s encoded in %ld bytes", + edx, elm->name, td->name, (long)tmperval.encoded); + } + + if(computed_size != 0) + /* + * Encoded size is not equal to the computed size. + */ + ASN__ENCODE_FAILED; + + ASN__ENCODED_OK(erval); +}