X-Git-Url: https://gerrit.o-ran-sc.org/r/gitweb?p=sim%2Fe2-interface.git;a=blobdiff_plain;f=e2sim%2Fasn1c%2FOCTET_STRING_ber.c;fp=e2sim%2Fasn1c%2FOCTET_STRING_ber.c;h=9530eaedb7622e43eb1ef739e1e3ff5012b80bd9;hp=0000000000000000000000000000000000000000;hb=f5900596513e4359fc839ba361da085674e90b68;hpb=215d350dbe06a4c7ee370815f26128a7f7e160cb diff --git a/e2sim/asn1c/OCTET_STRING_ber.c b/e2sim/asn1c/OCTET_STRING_ber.c new file mode 100644 index 0000000..9530eae --- /dev/null +++ b/e2sim/asn1c/OCTET_STRING_ber.c @@ -0,0 +1,525 @@ +/* + * Copyright (c) 2017 Lev Walkin . + * All rights reserved. + * Redistribution and modifications are permitted subject to BSD license. + */ +#include +#include +#include /* for .bits_unused member */ + +#undef _CH_PHASE +#define _CH_PHASE(ctx, inc) do {\ + if(ctx->phase == 0)\ + ctx->context = 0;\ + ctx->phase += inc;\ + } while(0) + +#undef NEXT_PHASE +#define NEXT_PHASE(ctx) _CH_PHASE(ctx, +1) +#undef PREV_PHASE +#define PREV_PHASE(ctx) _CH_PHASE(ctx, -1) + +#undef ADVANCE +#define ADVANCE(num_bytes) do {\ + size_t num = (num_bytes);\ + buf_ptr = ((const char *)buf_ptr) + num;\ + size -= num;\ + consumed_myself += num;\ + } while(0) + +#undef RETURN +#define RETURN(_code) do {\ + asn_dec_rval_t tmprval;\ + tmprval.code = _code;\ + tmprval.consumed = consumed_myself;\ + return tmprval;\ + } while(0) + +#undef APPEND +#define APPEND(bufptr, bufsize) do {\ + size_t _bs = (bufsize); /* Append size */\ + size_t _ns = ctx->context; /* Allocated now */\ + size_t _es = st->size + _bs; /* Expected size */\ + /* int is really a typeof(st->size): */\ + if((int)_es < 0) RETURN(RC_FAIL);\ + if(_ns <= _es) {\ + void *ptr;\ + /* Be nice and round to the memory allocator */\ + do { _ns = _ns ? _ns << 1 : 16; }\ + while(_ns <= _es);\ + /* int is really a typeof(st->size): */\ + if((int)_ns < 0) RETURN(RC_FAIL);\ + ptr = REALLOC(st->buf, _ns);\ + if(ptr) {\ + st->buf = (uint8_t *)ptr;\ + ctx->context = _ns;\ + } else {\ + RETURN(RC_FAIL);\ + }\ + ASN_DEBUG("Reallocating into %ld", (long)_ns);\ + }\ + memcpy(st->buf + st->size, bufptr, _bs);\ + /* Convenient nul-termination */\ + st->buf[_es] = '\0';\ + st->size = _es;\ + } while(0) + +/* + * The main reason why ASN.1 is still alive is that too much time and effort + * is necessary for learning it more or less adequately, thus creating a gut + * necessity to demonstrate that acquired skill everywhere afterwards. + * No, I am not going to explain what the following stuff is. + */ +static struct _stack_el * +OS__add_stack_el(struct _stack *st) { + struct _stack_el *nel; + + /* + * Reuse the old stack frame or allocate a new one. + */ + if(st->cur_ptr && st->cur_ptr->next) { + nel = st->cur_ptr->next; + nel->bits_chopped = 0; + nel->got = 0; + /* Retain the nel->cont_level, it's correct. */ + } else { + nel = (struct _stack_el *)CALLOC(1, sizeof(struct _stack_el)); + if(nel == NULL) + return NULL; + + if(st->tail) { + /* Increase a subcontainment depth */ + nel->cont_level = st->tail->cont_level + 1; + st->tail->next = nel; + } + nel->prev = st->tail; + st->tail = nel; + } + + st->cur_ptr = nel; + + return nel; +} + +static struct _stack * +_new_stack(void) { + return (struct _stack *)CALLOC(1, sizeof(struct _stack)); +} + +/* + * Decode OCTET STRING type. + */ +asn_dec_rval_t +OCTET_STRING_decode_ber(const asn_codec_ctx_t *opt_codec_ctx, + const asn_TYPE_descriptor_t *td, void **sptr, + const void *buf_ptr, size_t size, int tag_mode) { + const asn_OCTET_STRING_specifics_t *specs = td->specifics + ? (const asn_OCTET_STRING_specifics_t *)td->specifics + : &asn_SPC_OCTET_STRING_specs; + BIT_STRING_t *st = (BIT_STRING_t *)*sptr; + asn_dec_rval_t rval; + asn_struct_ctx_t *ctx; + ssize_t consumed_myself = 0; + struct _stack *stck; /* Expectations stack structure */ + struct _stack_el *sel = 0; /* Stack element */ + int tlv_constr; + enum asn_OS_Subvariant type_variant = specs->subvariant; + + ASN_DEBUG("Decoding %s as %s (frame %ld)", + td->name, + (type_variant == ASN_OSUBV_STR) ? + "OCTET STRING" : "OS-SpecialCase", + (long)size); + + /* + * Create the string if does not exist. + */ + if(st == NULL) { + st = (BIT_STRING_t *)(*sptr = CALLOC(1, specs->struct_size)); + if(st == NULL) RETURN(RC_FAIL); + } + + /* Restore parsing context */ + ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset); + + switch(ctx->phase) { + case 0: + /* + * Check tags. + */ + rval = ber_check_tags(opt_codec_ctx, td, ctx, + buf_ptr, size, tag_mode, -1, + &ctx->left, &tlv_constr); + if(rval.code != RC_OK) + return rval; + + if(tlv_constr) { + /* + * Complex operation, requires stack of expectations. + */ + ctx->ptr = _new_stack(); + if(!ctx->ptr) { + RETURN(RC_FAIL); + } + } else { + /* + * Jump into stackless primitive decoding. + */ + _CH_PHASE(ctx, 3); + if(type_variant == ASN_OSUBV_ANY && tag_mode != 1) + APPEND(buf_ptr, rval.consumed); + ADVANCE(rval.consumed); + goto phase3; + } + + NEXT_PHASE(ctx); + /* Fall through */ + case 1: + phase1: + /* + * Fill the stack with expectations. + */ + stck = (struct _stack *)ctx->ptr; + sel = stck->cur_ptr; + do { + ber_tlv_tag_t tlv_tag; + ber_tlv_len_t tlv_len; + ber_tlv_tag_t expected_tag; + ssize_t tl, ll, tlvl; + /* This one works even if (sel->left == -1) */ + size_t Left = ((!sel||(size_t)sel->left >= size) + ?size:(size_t)sel->left); + + + ASN_DEBUG("%p, s->l=%ld, s->wn=%ld, s->g=%ld\n", (void *)sel, + (long)(sel?sel->left:0), + (long)(sel?sel->want_nulls:0), + (long)(sel?sel->got:0) + ); + if(sel && sel->left <= 0 && sel->want_nulls == 0) { + if(sel->prev) { + struct _stack_el *prev = sel->prev; + if(prev->left != -1) { + if(prev->left < sel->got) + RETURN(RC_FAIL); + prev->left -= sel->got; + } + prev->got += sel->got; + sel = stck->cur_ptr = prev; + if(!sel) break; + tlv_constr = 1; + continue; + } else { + sel = stck->cur_ptr = 0; + break; /* Nothing to wait */ + } + } + + tl = ber_fetch_tag(buf_ptr, Left, &tlv_tag); + ASN_DEBUG("fetch tag(size=%ld,L=%ld), %sstack, left=%ld, wn=%ld, tl=%ld", + (long)size, (long)Left, sel?"":"!", + (long)(sel?sel->left:0), + (long)(sel?sel->want_nulls:0), + (long)tl); + switch(tl) { + case -1: RETURN(RC_FAIL); + case 0: RETURN(RC_WMORE); + } + + tlv_constr = BER_TLV_CONSTRUCTED(buf_ptr); + + ll = ber_fetch_length(tlv_constr, + (const char *)buf_ptr + tl,Left - tl,&tlv_len); + ASN_DEBUG("Got tag=%s, tc=%d, left=%ld, tl=%ld, len=%ld, ll=%ld", + ber_tlv_tag_string(tlv_tag), tlv_constr, + (long)Left, (long)tl, (long)tlv_len, (long)ll); + switch(ll) { + case -1: RETURN(RC_FAIL); + case 0: RETURN(RC_WMORE); + } + + if(sel && sel->want_nulls + && ((const uint8_t *)buf_ptr)[0] == 0 + && ((const uint8_t *)buf_ptr)[1] == 0) + { + ASN_DEBUG("Eat EOC; wn=%d--", sel->want_nulls); + + if(type_variant == ASN_OSUBV_ANY + && (tag_mode != 1 || sel->cont_level)) + APPEND("\0\0", 2); + + ADVANCE(2); + sel->got += 2; + if(sel->left != -1) { + sel->left -= 2; /* assert(sel->left >= 2) */ + } + + sel->want_nulls--; + if(sel->want_nulls == 0) { + /* Move to the next expectation */ + sel->left = 0; + tlv_constr = 1; + } + + continue; + } + + /* + * Set up expected tags, + * depending on ASN.1 type being decoded. + */ + switch(type_variant) { + case ASN_OSUBV_BIT: + /* X.690: 8.6.4.1, NOTE 2 */ + /* Fall through */ + case ASN_OSUBV_STR: + default: + if(sel) { + unsigned level = sel->cont_level; + if(level < td->all_tags_count) { + expected_tag = td->all_tags[level]; + break; + } else if(td->all_tags_count) { + expected_tag = td->all_tags + [td->all_tags_count - 1]; + break; + } + /* else, Fall through */ + } + /* Fall through */ + case ASN_OSUBV_ANY: + expected_tag = tlv_tag; + break; + } + + if(tlv_tag != expected_tag) { + char buf[2][32]; + ber_tlv_tag_snprint(tlv_tag, + buf[0], sizeof(buf[0])); + ber_tlv_tag_snprint(td->tags[td->tags_count-1], + buf[1], sizeof(buf[1])); + ASN_DEBUG("Tag does not match expectation: %s != %s", + buf[0], buf[1]); + RETURN(RC_FAIL); + } + + tlvl = tl + ll; /* Combined length of T and L encoding */ + if((tlv_len + tlvl) < 0) { + /* tlv_len value is too big */ + ASN_DEBUG("TLV encoding + length (%ld) is too big", + (long)tlv_len); + RETURN(RC_FAIL); + } + + /* + * Append a new expectation. + */ + sel = OS__add_stack_el(stck); + if(!sel) RETURN(RC_FAIL); + + sel->tag = tlv_tag; + + sel->want_nulls = (tlv_len==-1); + if(sel->prev && sel->prev->left != -1) { + /* Check that the parent frame is big enough */ + if(sel->prev->left < tlvl + (tlv_len==-1?0:tlv_len)) + RETURN(RC_FAIL); + if(tlv_len == -1) + sel->left = sel->prev->left - tlvl; + else + sel->left = tlv_len; + } else { + sel->left = tlv_len; + } + if(type_variant == ASN_OSUBV_ANY + && (tag_mode != 1 || sel->cont_level)) + APPEND(buf_ptr, tlvl); + sel->got += tlvl; + ADVANCE(tlvl); + + ASN_DEBUG("+EXPECT2 got=%ld left=%ld, wn=%d, clvl=%u", + (long)sel->got, (long)sel->left, + sel->want_nulls, sel->cont_level); + + } while(tlv_constr); + if(sel == NULL) { + /* Finished operation, "phase out" */ + ASN_DEBUG("Phase out"); + _CH_PHASE(ctx, +3); + break; + } + + NEXT_PHASE(ctx); + /* Fall through */ + case 2: + stck = (struct _stack *)ctx->ptr; + sel = stck->cur_ptr; + ASN_DEBUG("Phase 2: Need %ld bytes, size=%ld, alrg=%ld, wn=%d", + (long)sel->left, (long)size, (long)sel->got, + sel->want_nulls); + { + ber_tlv_len_t len; + + assert(sel->left >= 0); + + len = ((ber_tlv_len_t)size < sel->left) + ? (ber_tlv_len_t)size : sel->left; + if(len > 0) { + if(type_variant == ASN_OSUBV_BIT + && sel->bits_chopped == 0) { + /* Put the unused-bits-octet away */ + st->bits_unused = *(const uint8_t *)buf_ptr; + APPEND(((const char *)buf_ptr+1), (len - 1)); + sel->bits_chopped = 1; + } else { + APPEND(buf_ptr, len); + } + ADVANCE(len); + sel->left -= len; + sel->got += len; + } + + if(sel->left) { + ASN_DEBUG("OS left %ld, size = %ld, wn=%d\n", + (long)sel->left, (long)size, sel->want_nulls); + RETURN(RC_WMORE); + } + + PREV_PHASE(ctx); + goto phase1; + } + break; + case 3: + phase3: + /* + * Primitive form, no stack required. + */ + assert(ctx->left >= 0); + + if(size < (size_t)ctx->left) { + if(!size) RETURN(RC_WMORE); + if(type_variant == ASN_OSUBV_BIT && !ctx->context) { + st->bits_unused = *(const uint8_t *)buf_ptr; + ctx->left--; + ADVANCE(1); + } + APPEND(buf_ptr, size); + assert(ctx->context > 0); + ctx->left -= size; + ADVANCE(size); + RETURN(RC_WMORE); + } else { + if(type_variant == ASN_OSUBV_BIT + && !ctx->context && ctx->left) { + st->bits_unused = *(const uint8_t *)buf_ptr; + ctx->left--; + ADVANCE(1); + } + APPEND(buf_ptr, ctx->left); + ADVANCE(ctx->left); + ctx->left = 0; + + NEXT_PHASE(ctx); + } + break; + } + + if(sel) { + ASN_DEBUG("3sel p=%p, wn=%d, l=%ld, g=%ld, size=%ld", + (void *)sel->prev, sel->want_nulls, + (long)sel->left, (long)sel->got, (long)size); + if(sel->prev || sel->want_nulls > 1 || sel->left > 0) { + RETURN(RC_WMORE); + } + } + + /* + * BIT STRING-specific processing. + */ + if(type_variant == ASN_OSUBV_BIT) { + if(st->size) { + if(st->bits_unused < 0 || st->bits_unused > 7) { + RETURN(RC_FAIL); + } + /* Finalize BIT STRING: zero out unused bits. */ + st->buf[st->size-1] &= 0xff << st->bits_unused; + } else { + if(st->bits_unused) { + RETURN(RC_FAIL); + } + } + } + + ASN_DEBUG("Took %ld bytes to encode %s: [%s]:%ld", + (long)consumed_myself, td->name, + (type_variant == ASN_OSUBV_STR) ? (char *)st->buf : "", + (long)st->size); + + + RETURN(RC_OK); +} + +/* + * Encode OCTET STRING type using DER. + */ +asn_enc_rval_t +OCTET_STRING_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) { + asn_enc_rval_t er = { 0, 0, 0 }; + const asn_OCTET_STRING_specifics_t *specs = td->specifics + ? (const asn_OCTET_STRING_specifics_t *)td->specifics + : &asn_SPC_OCTET_STRING_specs; + const BIT_STRING_t *st = (const BIT_STRING_t *)sptr; + enum asn_OS_Subvariant type_variant = specs->subvariant; + int fix_last_byte = 0; + + ASN_DEBUG("%s %s as OCTET STRING", + cb?"Estimating":"Encoding", td->name); + + /* + * Write tags. + */ + if(type_variant != ASN_OSUBV_ANY || tag_mode == 1) { + er.encoded = der_write_tags(td, + (type_variant == ASN_OSUBV_BIT) + st->size, + tag_mode, type_variant == ASN_OSUBV_ANY, tag, + cb, app_key); + if(er.encoded == -1) { + er.failed_type = td; + er.structure_ptr = sptr; + return er; + } + } else { + /* Disallow: [] IMPLICIT ANY */ + assert(type_variant != ASN_OSUBV_ANY || tag_mode != -1); + er.encoded = 0; + } + + if(!cb) { + er.encoded += (type_variant == ASN_OSUBV_BIT) + st->size; + ASN__ENCODED_OK(er); + } + + /* + * Prepare to deal with the last octet of BIT STRING. + */ + if(type_variant == ASN_OSUBV_BIT) { + uint8_t b = st->bits_unused & 0x07; + if(b && st->size) fix_last_byte = 1; + ASN__CALLBACK(&b, 1); + } + + /* Invoke callback for the main part of the buffer */ + ASN__CALLBACK(st->buf, st->size - fix_last_byte); + + /* The last octet should be stripped off the unused bits */ + if(fix_last_byte) { + uint8_t b = st->buf[st->size-1] & (0xff << st->bits_unused); + ASN__CALLBACK(&b, 1); + } + + ASN__ENCODED_OK(er); +cb_failed: + ASN__ENCODE_FAILED; +}