[nrf fromlist] drivers: nrfwifi: Fix memory leak in TX path

During secure association, if we get any data packets from the
networking stack (as we switch off the dormancy) then they will be
dropped till the 802.1x port is authorized, but with recent changes the
corresponding network buffer isn't freed causing a memory leak.

Handle this case and free the network buffer (Using an OSAL API though
it's Zephyr to avoid duplication and also getting access to "struct
nwb");

Upstream PR #: 80528

Signed-off-by: Chaitanya Tata <[email protected]>
(cherry picked from commit 979a672)

drivers/wifi/nrfwifi/src/net_if.c

@@ -389,7 +389,7 @@ int nrf_wifi_if_send(const struct device *dev,
 #ifdef CONFIG_NRF70_RAW_DATA_TX
 	if ((*(unsigned int *)pkt->frags->data) == NRF_WIFI_MAGIC_NUM_RAWTX) {
 		if (vif_ctx_zep->if_carr_state != NRF_WIFI_FMAC_IF_CARR_STATE_ON) {
-			goto unlock;
+			goto drop;
 		}
 
 		ret = nrf_wifi_fmac_start_rawpkt_xmit(rpu_ctx_zep->rpu_ctx,
@@ -399,7 +399,7 @@ int nrf_wifi_if_send(const struct device *dev,
 #endif /* CONFIG_NRF70_RAW_DATA_TX */
 		if ((vif_ctx_zep->if_carr_state != NRF_WIFI_FMAC_IF_CARR_STATE_ON) ||
 		    (!vif_ctx_zep->authorized && !is_eapol(pkt))) {
-			goto unlock;
+			goto drop;
 		}
 
 		ret = nrf_wifi_fmac_start_xmit(rpu_ctx_zep->rpu_ctx,
@@ -408,6 +408,10 @@ int nrf_wifi_if_send(const struct device *dev,
 #ifdef CONFIG_NRF70_RAW_DATA_TX
 	}
 #endif /* CONFIG_NRF70_RAW_DATA_TX */
+	goto unlock;
+drop:
+	host_stats->total_tx_drop_pkts++;
+	nrf_wifi_osal_nbuf_free(nbuf);
 unlock:
 	k_mutex_unlock(&vif_ctx_zep->vif_lock);
 #else