Add support for random MAC address

Add a build time option to generate random MAC address, this helps in test deployments. Used Zephyr API in the BM code to simplify things, as srand() was giving same MAC address (seed problems). Signed-off-by: Chaitanya Tata <[email protected]>
nrfconnect · Dec 5, 2024 · f11733a · f11733a
1 parent c13291a
commit f11733a
Show file tree

Hide file tree

Showing 3 changed files with 39 additions and 1 deletion.
diff --git a/nrf70_bm_lib/Kconfig b/nrf70_bm_lib/Kconfig
@@ -48,8 +48,8 @@ config NRF70_FIXED_MAC_ADDRESS
 
 choice
 	prompt "Wi-Fi MAC address type"
-	default NRF70_OTP_MAC_ADDRESS if NRF70_FIXED_MAC_ADDRESS = ""
 	default NRF70_FIXED_MAC_ADDRESS_ENABLED if NRF70_FIXED_MAC_ADDRESS != ""
+	default NRF70_OTP_MAC_ADDRESS
 	help
 	  Select the type of MAC address to be used by the Wi-Fi driver
 
@@ -62,6 +62,13 @@ config NRF70_FIXED_MAC_ADDRESS_ENABLED
 	bool "Enable fixed MAC address"
 	help
 	  Enable fixed MAC address
+
+config NRF70_RANDOM_MAC_ADDRESS
+	bool "Random MAC address generation at runtime"
+	select TEST_RANDOM_GENERATOR
+	help
+	  This option enables random MAC address generation at runtime.
+	  The random MAC address is generated using the libc srand() function.
 endchoice
 
 config NRF700X_LOG_VERBOSE

diff --git a/nrf70_bm_lib/docs/source/nrf70_bm_porting_guide.rst b/nrf70_bm_lib/docs/source/nrf70_bm_porting_guide.rst
@@ -47,6 +47,10 @@ The reference implementation of the BM Driver for the Zephyr RTOS uses build-tim
     - Used to manage the timers for the nRF70 Series driver, esp. for low power mode.
     - timer_***
     - k_work_delayable_***
+  * - PRNG
+    - Used to generate random numbers for the nRF70 Series random MAC address generation.
+    - NA
+    - sys_rand8_get()
 
 
 .. note ::

diff --git a/nrf70_bm_lib/source/nrf70_bm_core.c b/nrf70_bm_lib/source/nrf70_bm_core.c
@@ -7,6 +7,10 @@
 /** @file
  * @brief nRF70 Bare Metal initialization.
  */
+#ifdef CONFIG_NRF70_RANDOM_MAC_ADDRESS
+#include <zephyr/random/random.h>
+#endif /* CONFIG_NRF70_RANDOM_MAC_ADDRESS */
+
 #include "nrf70_bm_core.h"
 #include "nrf70_bm_lib.h"
 
@@ -451,11 +455,28 @@ int nrf70_fmac_init(void)
 	return -1;
 }
 
+#ifdef CONFIG_NRF70_RANDOM_MAC_ADDRESS
+static void generate_random_mac_address(uint8_t *mac_addr)
+{
+	// For simplicty use Zephyr API to generate random number
+	for (int i = 0; i < 6; i++) {
+		mac_addr[i] = sys_rand8_get();
+	}
+
+	// Set the locally administered bit (bit 1 of the first byte)
+	mac_addr[0] |= 0x02;
+
+	// Clear the multicast bit (bit 0 of the first byte)
+	mac_addr[0] &= 0xFE;
+}
+#endif /* CONFIG_WIFI_RANDOM_MAC_ADDRESS */
 
 enum nrf_wifi_status nrf_wifi_get_mac_addr(struct nrf70_wifi_vif_bm *vif)
 {
 	enum nrf_wifi_status status = NRF_WIFI_STATUS_FAIL;
+#ifndef CONFIG_NRF70_RANDOM_MAC_ADDRESS
 	void *rpu_ctx = nrf70_bm_priv.rpu_ctx_bm.rpu_ctx;
+#endif /* CONFIG_NRF70_RANDOM_MAC_ADDRESS */
 	struct nrf_wifi_fmac_priv *fmac_priv = nrf70_bm_priv.fmac_priv;
 	unsigned char mac_addr_str[18];
 #ifdef CONFIG_NRF70_FIXED_MAC_ADDRESS_ENABLED
@@ -474,6 +495,8 @@ enum nrf_wifi_status nrf_wifi_get_mac_addr(struct nrf70_wifi_vif_bm *vif)
 	}
 
 	memcpy(vif->mac_addr, fixed_mac_addr, NR70_MAC_ADDR_LEN);
+#elif CONFIG_NRF70_RANDOM_MAC_ADDRESS
+	generate_random_mac_address(vif->mac_addr);
 #elif CONFIG_NRF70_OTP_MAC_ADDRESS
 	status = nrf_wifi_fmac_otp_mac_addr_get(rpu_ctx,
 											vif->vif_idx,
@@ -536,6 +559,10 @@ int nrf70_fmac_add_vif_sta(void)
 		goto del_vif;
 	}
 
+	NRF70_LOG_INF("MAC address set to %02X:%02X:%02X:%02X:%02X:%02X",
+		vif->mac_addr[0], vif->mac_addr[1], vif->mac_addr[2],
+		vif->mac_addr[3], vif->mac_addr[4], vif->mac_addr[5]);
+
 	memset(&vif_info, 0, sizeof(vif_info));
 	vif_info.state = NRF_WIFI_FMAC_IF_OP_STATE_UP;
 	vif_info.if_index = vif->vif_idx;