101 lines
3.3 KiB
C
101 lines
3.3 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdint.h>
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#include "conversion.h"
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#include "access_restriction.h"
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/* TODO: identification of MCC and MNC within an IMSI should be done according
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* to a table that maps MCC to 2 or 3 digits expected...
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* By default we will assume there is only 2 digits for our use.
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*/
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/* Split a PLMN formed of <MCC><MNC> to mcc and mnc.
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* In case MNC is formed of only two digits a 0 is inserted at the most significant
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* digit.
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* When PLMN is represented using european convention it contains only two digits,
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* while three digits are used in North American Standard.
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* Encoding of PLMN is defined in ITU E.212.
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* @param plmn string either 5 or 6 digits resulting of the concatenation of
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* MCC and MNC.
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*/
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int split_plmn(uint8_t plmn[3], uint8_t mcc[3], uint8_t mnc[3])
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{
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if (plmn == NULL) {
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return -1;
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}
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mcc[0] = plmn[0] & 0x0F;
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mcc[1] = (plmn[0] & 0xF0) >> 4;
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mcc[2] = plmn[1] & 0x0F;
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if ((plmn[1] & 0xF0) == 0xF0) {
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/* Only 2 digits case */
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mnc[1] = plmn[2] & 0x0F;
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mnc[2] = (plmn[2] & 0xF0) >> 4;
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mnc[0] = 0;
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} else {
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mnc[0] = plmn[2] & 0x0F;
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mnc[1] = (plmn[2] & 0xF0) >> 4;
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mnc[2] = ((plmn[1] & 0xF0) >> 4);
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}
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return 0;
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}
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/* Apply restriction (if any) to current 'visited' PLMN for this user.
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* Criterias are based on ODB (operator determined barring), visited PLMN
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* and user PLMN (obtain from IMSI).
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* @param imsi is the user identity formed of MCC.MNC.MSIN (14 or 15 digits long)
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* @param vplmn is the plmn of the cell the UE is currently attached to
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*/
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#define FORMAT_MCC(mCC) (mCC[0] * 100 + mCC[1] * 10 + mCC[2])
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#define FORMAT_MNC(mNC) (mNC[0] * 100 + mNC[1] * 10 + mNC[2])
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int apply_access_restriction(char *imsi, uint8_t *vplmn)
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{
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uint8_t vmcc[3], vmnc[3];
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uint8_t hmcc[3], hmnc[3];
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uint8_t imsi_hex[15];
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if (bcd_to_hex(imsi_hex, imsi, strlen(imsi)) != 0) {
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fprintf(stderr, "Failed to convert imsi %s to hex representation\n",
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imsi);
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return -1;
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}
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/* There is a problem while converting the PLMN... */
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if (split_plmn(vplmn, vmcc, vmnc) != 0) {
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fprintf(stderr, "Fail to convert vplmn %02x%02x%02x to mcc/mnc for imsi %s\n",
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vplmn[0], vplmn[1], vplmn[2], imsi);
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return -1;
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}
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fprintf(stderr, "Converted %02x%02x%02x to plmn %u.%u\n", vplmn[0], vplmn[1], vplmn[2],
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FORMAT_MCC(vmcc), FORMAT_MNC(vmnc));
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/* MCC is always 3 digits */
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memcpy(hmcc, &imsi_hex[0], 3);
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if (memcmp(vmcc, hmcc, 3) != 0) {
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fprintf(stderr, "Only France MCC is handled for now, got imsi plmn %u.%u for a visited plmn %u.%u\n",
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FORMAT_MCC(hmcc), FORMAT_MNC(hmnc), FORMAT_MCC(vmcc), FORMAT_MNC(vmnc));
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/* Reject the association */
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return -1;
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}
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/* In France MNC is composed of 2 digits and thus imsi by 14 digit */
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hmnc[0] = 0;
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memcpy(&hmnc[1], &imsi_hex[3], 2);
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if ((memcmp(vmcc, hmcc, 3) != 0) && (memcmp(vmnc, hmnc, 3) != 0)) {
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fprintf(stderr, "UE is roaming from %u.%u to %u.%u which is not allowed"
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" by the ODB\n", FORMAT_MCC(hmcc), FORMAT_MNC(hmnc), FORMAT_MCC(vmcc), FORMAT_MNC(vmnc));
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return -1;
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}
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/* User has successfully passed all the checking -> accept the association */
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return 0;
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}
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