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nimble/ll: Use NRPA for scan requests to unknown devices

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With privacy enabled, we'll use NRPA instead of identity address to
send scan requests to devices which are not on our resolving list.
This is to prevent us from being tracked when doing active scanning.

X-Original-Commit: 0cde652d1eef0b7f7ef202e7418284e675687cfa
This commit is contained in:
Andrzej Kaczmarek
2018-02-13 11:35:18 +01:00
parent 68740d6427
commit dbdea0fb33
2 changed files with 39 additions and 1 deletions
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nimble/controller/include/controller/ble_ll_scan.h
+4
View File
@@ -119,6 +119,10 @@ struct ble_ll_scan_sm
uint8_t scan_rsp_cons_ok;
int8_t scan_rpa_index;
uint8_t scan_peer_rpa[BLE_DEV_ADDR_LEN];
#if (MYNEWT_VAL(BLE_LL_CFG_FEAT_LL_PRIVACY) == 1)
uint32_t scan_nrpa_timer;
uint8_t scan_nrpa[BLE_DEV_ADDR_LEN];
#endif
/* XXX: Shall we count backoff per phy? */
uint16_t upper_limit;
nimble/controller/src/ble_ll_scan.c
+35 -1
View File
@@ -263,6 +263,24 @@ ble_ll_scan_req_backoff(struct ble_ll_scan_sm *scansm, int success)
assert(scansm->backoff_count <= 256);
}
#if (MYNEWT_VAL(BLE_LL_CFG_FEAT_LL_PRIVACY) == 1)
static void
ble_ll_scan_refresh_nrpa(struct ble_ll_scan_sm *scansm)
{
uint32_t now;
now = os_time_get();
if ((int32_t)(now - scansm->scan_nrpa_timer) >= 0) {
/* Generate new NRPA */
ble_ll_rand_data_get(scansm->scan_nrpa, BLE_DEV_ADDR_LEN);
scansm->scan_nrpa[5] &= ~0xc0;
/* We'll use the same timeout as for RPA rotation */
scansm->scan_nrpa_timer = now + ble_ll_resolv_get_rpa_tmo();
}
}
#endif
/**
* ble ll scan req pdu make
*
@@ -318,11 +336,22 @@ ble_ll_scan_req_pdu_make(struct ble_ll_scan_sm *scansm, uint8_t *adv_addr,
}
}
/*
* If advertising device is on our resolving list, we use RPA generated
* using Local IRK from resolving list entry as ScanA. In other case,
* we use NRPA as ScanA as allowed by spec to prevent our device from
* being tracked when doing an active scan (see Core 5.0, Vol 6, Part B,
* section 6.3).
*/
if (rl) {
ble_ll_resolv_gen_priv_addr(rl, 1, rpa);
scana = rpa;
pdu_type |= BLE_ADV_PDU_HDR_TXADD_RAND;
} else {
ble_ll_scan_refresh_nrpa(scansm);
scana = scansm->scan_nrpa;
}
pdu_type |= BLE_ADV_PDU_HDR_TXADD_RAND;
}
#endif
@@ -3044,6 +3073,11 @@ ble_ll_scan_init(void)
scansm->phy_data[PHY_CODED].phy = BLE_PHY_CODED;
#endif
#if (MYNEWT_VAL(BLE_LL_CFG_FEAT_LL_PRIVACY) == 1)
/* Make sure we'll generate new NRPA if necessary */
scansm->scan_nrpa_timer = os_time_get();
#endif
/* Initialize scanning timer */
os_cputime_timer_init(&scansm->scan_timer, ble_ll_scan_timer_cb, scansm);