X-Git-Url: https://gerrit.o-ran-sc.org/r/gitweb?p=sim%2Fe2-interface.git;a=blobdiff_plain;f=e2sim%2Fasn1c%2Fuper_support.c;fp=e2sim%2Fasn1c%2Fuper_support.c;h=ce8adc5e72092947d43e5a37824af2ed3dd94dc5;hp=0000000000000000000000000000000000000000;hb=f5900596513e4359fc839ba361da085674e90b68;hpb=215d350dbe06a4c7ee370815f26128a7f7e160cb diff --git a/e2sim/asn1c/uper_support.c b/e2sim/asn1c/uper_support.c new file mode 100644 index 0000000..ce8adc5 --- /dev/null +++ b/e2sim/asn1c/uper_support.c @@ -0,0 +1,311 @@ +/* + * Copyright (c) 2005-2017 Lev Walkin . All rights reserved. + * Redistribution and modifications are permitted subject to BSD license. + */ +#include +#include +#include + +/* + * X.691-201508 #10.9 General rules for encoding a length determinant. + * Get the optionally constrained length "n" from the stream. + */ +ssize_t +uper_get_length(asn_per_data_t *pd, int ebits, size_t lower_bound, + int *repeat) { + ssize_t value; + + *repeat = 0; + + /* #11.9.4.1 Encoding if constrained (according to effective bits) */ + if(ebits >= 0 && ebits <= 16) { + value = per_get_few_bits(pd, ebits); + if(value >= 0) value += lower_bound; + return value; + } + + value = per_get_few_bits(pd, 8); + if((value & 0x80) == 0) { /* #11.9.3.6 */ + return (value & 0x7F); + } else if((value & 0x40) == 0) { /* #11.9.3.7 */ + /* bit 8 ... set to 1 and bit 7 ... set to zero */ + value = ((value & 0x3f) << 8) | per_get_few_bits(pd, 8); + return value; /* potential -1 from per_get_few_bits passes through. */ + } else if(value < 0) { + ASN_DEBUG("END of stream reached for PER"); + return -1; + } + value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */ + if(value < 1 || value > 4) { + return -1; /* Prohibited by #11.9.3.8 */ + } + *repeat = 1; + return (16384 * value); +} + +/* + * Get the normally small length "n". + * This procedure used to decode length of extensions bit-maps + * for SET and SEQUENCE types. + */ +ssize_t +uper_get_nslength(asn_per_data_t *pd) { + ssize_t length; + + ASN_DEBUG("Getting normally small length"); + + if(per_get_few_bits(pd, 1) == 0) { + length = per_get_few_bits(pd, 6) + 1; + if(length <= 0) return -1; + ASN_DEBUG("l=%d", (int)length); + return length; + } else { + int repeat; + length = uper_get_length(pd, -1, 0, &repeat); + if(length >= 0 && !repeat) return length; + return -1; /* Error, or do not support >16K extensions */ + } +} + +/* + * Get the normally small non-negative whole number. + * X.691, #10.6 + */ +ssize_t +uper_get_nsnnwn(asn_per_data_t *pd) { + ssize_t value; + + value = per_get_few_bits(pd, 7); + if(value & 64) { /* implicit (value < 0) */ + value &= 63; + value <<= 2; + value |= per_get_few_bits(pd, 2); + if(value & 128) /* implicit (value < 0) */ + return -1; + if(value == 0) + return 0; + if(value >= 3) + return -1; + value = per_get_few_bits(pd, 8 * value); + return value; + } + + return value; +} + +/* + * X.691-11/2008, #11.6 + * Encoding of a normally small non-negative whole number + */ +int +uper_put_nsnnwn(asn_per_outp_t *po, int n) { + int bytes; + + if(n <= 63) { + if(n < 0) return -1; + return per_put_few_bits(po, n, 7); + } + if(n < 256) + bytes = 1; + else if(n < 65536) + bytes = 2; + else if(n < 256 * 65536) + bytes = 3; + else + return -1; /* This is not a "normally small" value */ + if(per_put_few_bits(po, bytes, 8)) + return -1; + + return per_put_few_bits(po, n, 8 * bytes); +} + + +/* X.691-2008/11, #11.5.6 -> #11.3 */ +int uper_get_constrained_whole_number(asn_per_data_t *pd, uintmax_t *out_value, int nbits) { + uintmax_t lhalf; /* Lower half of the number*/ + intmax_t half; + + if(nbits <= 31) { + half = per_get_few_bits(pd, nbits); + if(half < 0) return -1; + *out_value = half; + return 0; + } + + if((size_t)nbits > 8 * sizeof(*out_value)) + return -1; /* RANGE */ + + half = per_get_few_bits(pd, 31); + if(half < 0) return -1; + + if(uper_get_constrained_whole_number(pd, &lhalf, nbits - 31)) + return -1; + + *out_value = ((uintmax_t)half << (nbits - 31)) | lhalf; + return 0; +} + + +/* X.691-2008/11, #11.5.6 -> #11.3 */ +int +uper_put_constrained_whole_number_u(asn_per_outp_t *po, uintmax_t v, + int nbits) { + if(nbits <= 31) { + return per_put_few_bits(po, v, nbits); + } else { + /* Put higher portion first, followed by lower 31-bit */ + if(uper_put_constrained_whole_number_u(po, v >> 31, nbits - 31)) + return -1; + return per_put_few_bits(po, v, 31); + } +} + +/* + * X.691 (08/2015) #11.9 "General rules for encoding a length determinant" + * Put the length "n" (or part of it) into the stream. + */ +ssize_t +uper_put_length(asn_per_outp_t *po, size_t length, int *need_eom) { + int dummy = 0; + if(!need_eom) need_eom = &dummy; + + if(length <= 127) { /* #11.9.3.6 */ + *need_eom = 0; + return per_put_few_bits(po, length, 8) + ? -1 : (ssize_t)length; + } else if(length < 16384) { /* #10.9.3.7 */ + *need_eom = 0; + return per_put_few_bits(po, length|0x8000, 16) + ? -1 : (ssize_t)length; + } + + *need_eom = 0 == (length & 16383); + length >>= 14; + if(length > 4) { + *need_eom = 0; + length = 4; + } + + return per_put_few_bits(po, 0xC0 | length, 8) + ? -1 : (ssize_t)(length << 14); + +} + + +/* + * Put the normally small length "n" into the stream. + * This procedure used to encode length of extensions bit-maps + * for SET and SEQUENCE types. + */ +int +uper_put_nslength(asn_per_outp_t *po, size_t length) { + if(length <= 64) { + /* #11.9.3.4 */ + if(length == 0) return -1; + return per_put_few_bits(po, length - 1, 7) ? -1 : 0; + } else { + int need_eom = 0; + if(uper_put_length(po, length, &need_eom) != (ssize_t)length + || need_eom) { + /* This might happen in case of >16K extensions */ + return -1; + } + } + + return 0; +} + +static int +per__imax_range(intmax_t lb, intmax_t ub, uintmax_t *range_r) { + uintmax_t bounds_range; + if((ub < 0) == (lb < 0)) { + bounds_range = ub - lb; + } else if(lb < 0) { + assert(ub >= 0); + bounds_range = 1 + ((uintmax_t)ub + (uintmax_t)-(lb + 1)); + } else { + assert(!"Unreachable"); + return -1; + } + *range_r = bounds_range; + return 0; +} + +int +per_imax_range_rebase(intmax_t v, intmax_t lb, intmax_t ub, uintmax_t *output) { + uintmax_t range; + + assert(lb <= ub); + + if(v < lb || v > ub || per__imax_range(lb, ub, &range) < 0) { + /* Range error. */ + return -1; + } + + /* + * Fundamentally what we're doing is returning (v-lb). + * However, this triggers undefined behavior when the word width + * of signed (v) is the same as the size of unsigned (*output). + * In practice, it triggers the UndefinedSanitizer. Therefore we shall + * compute the ranges accurately to avoid C's undefined behavior. + */ + if((v < 0) == (lb < 0)) { + *output = v-lb; + return 0; + } else if(v < 0) { + uintmax_t rebased = 1 + (uintmax_t)-(v+1) + (uintmax_t)lb; + assert(rebased <= range); /* By construction */ + *output = rebased; + return 0; + } else if(lb < 0) { + uintmax_t rebased = 1 + (uintmax_t)-(lb+1) + (uintmax_t)v; + assert(rebased <= range); /* By construction */ + *output = rebased; + return 0; + } else { + assert(!"Unreachable"); + return -1; + } +} + +int +per_long_range_rebase(long v, intmax_t lb, intmax_t ub, unsigned long *output) { + uintmax_t tmp = *output; + int rc = per_imax_range_rebase((intmax_t)v, lb, ub, &tmp); + *output = tmp; + return rc; +} + +int +per_imax_range_unrebase(uintmax_t inp, intmax_t lb, intmax_t ub, intmax_t *outp) { + uintmax_t range; + + if(per__imax_range(lb, ub, &range) != 0) { + return -1; + } + + if(inp > range) { + /* + * We can encode something in the given number of bits that technically + * exceeds the range. This is an avenue for security errors, + * so we don't allow that. + */ + return -1; + } + + if(inp <= INTMAX_MAX) { + *outp = (intmax_t)inp + lb; + } else { + *outp = (lb + INTMAX_MAX + 1) + (intmax_t)((inp - INTMAX_MAX) - 1); + } + + return 0; +} + +int +per_long_range_unrebase(unsigned long inp, intmax_t lb, intmax_t ub, long *outp) { + intmax_t tmp = *outp; + int rc = per_imax_range_unrebase((uintmax_t)inp, lb, ub, &tmp); + *outp = tmp; + return rc; +}