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