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/* Iu interface specific helper functions */
/* (C) 2015 by Harald Welte <laforge@gnumonks.org>
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include "asn1helpers.h"
#include <osmocom/core/utils.h>
#include <osmocom/ranap/RANAP_IuTransportAssociation.h>
#include <osmocom/ranap/RANAP_TransportLayerAddress.h>
/* decode a BCD-string as used inside ASN.1 encoded Iu interface protocols */
int ranap_bcd_decode(char *out, size_t out_len, const uint8_t *in, size_t in_len)
{
const uint8_t *ch;
char *outch = out;
for (ch = in; ch < in + in_len; ch++) {
char c = osmo_bcd2char(*ch & 0xF);
*outch++ = c;
if (outch + 1 >= out + out_len)
break;
c = osmo_bcd2char(*ch >> 4);
/* skip padding nibble at end */
if (c == 'F')
break;
*outch++ = c;
}
*outch++ = '\0';
return outch - out;
}
/* decode an IMSI as used inside ASN.1 encoded Iu interface protocols */
int ranap_imsi_encode(uint8_t *out, size_t out_len, const char *in)
{
unsigned int len = strlen(in);
unsigned int octlen;
uint8_t odd = (len & 0x01) == 1;
unsigned int off = 0;
unsigned int i;
octlen = len/2;
if (odd)
octlen++;
for (i = 0; i < octlen; i++) {
uint8_t lower, upper;
lower = osmo_char2bcd(in[off++]) & 0x0f;
if (odd && off == len)
upper = 0x0f;
else
upper = osmo_char2bcd(in[off++]) & 0x0f;
out[i] = (upper << 4) | lower;
}
return i;
}
/* decode a network port as used inside ASN.1 encoded Iu interface protocols */
int ranap_transp_assoc_decode(uint16_t *port, const RANAP_IuTransportAssociation_t *transp_assoc)
{
uint32_t result;
if (!transp_assoc)
return -EINVAL;
result = asn1bitstr_to_u32((BIT_STRING_t *) & transp_assoc->choice.bindingID);
/* The lower 16 bits should be zero, otherwise the decoding may
* have yielded some odd result */
if (result & 0xFFFF)
return -EINVAL;
*port = (uint16_t) ((result >> 16) & 0xFFFF);
if (*port == 0)
return -EINVAL;
return 0;
}
/* decode a network address as used inside ASN.1 encoded Iu interface protocols */
int ranap_transp_layer_addr_decode(char *addr, unsigned int addr_len,
const RANAP_TransportLayerAddress_t *trasp_layer_addr)
{
unsigned char *buf;
int len;
const char *rc;
buf = trasp_layer_addr->buf;
len = trasp_layer_addr->size;
if (buf[0] == 0x35 && len >= 7)
rc = inet_ntop(AF_INET, buf + 3, addr, addr_len);
else if (len > 3)
rc = inet_ntop(AF_INET, buf, addr, addr_len);
else
return -EINVAL;
if (!rc)
return -EINVAL;
return 0;
}
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