Promiscuous Mode
Overview
Promiscuous mode is a mode for a network interface controller that causes it to pass all traffic it receives to the application rather than passing only the frames that the controller is specifically programmed to receive. This mode is normally used for packet sniffing as used to diagnose network connectivity issues by showing an application all the data being transferred over the network. (See the Wikipedia article on promiscuous mode for more information.)
The network promiscuous APIs are used to enable and disable this mode, and to wait for and receive a network data to arrive. Not all network technologies or network device drivers support promiscuous mode.
Sample usage
First the promiscuous mode needs to be turned ON by the application like this:
ret = net_promisc_mode_on(iface);
if (ret < 0) {
if (ret == -EALREADY) {
printf("Promiscuous mode already enabled\n");
} else {
printf("Cannot enable promiscuous mode for "
"interface %p (%d)\n", iface, ret);
}
}
If there is no error, then the application can start to wait for network data:
while (true) {
pkt = net_promisc_mode_wait_data(K_FOREVER);
if (pkt) {
print_info(pkt);
}
net_pkt_unref(pkt);
}
Finally the promiscuous mode can be turned OFF by the application like this:
ret = net_promisc_mode_off(iface);
if (ret < 0) {
if (ret == -EALREADY) {
printf("Promiscuous mode already disabled\n");
} else {
printf("Cannot disable promiscuous mode for "
"interface %p (%d)\n", iface, ret);
}
}
See Promiscuous Mode Sample Application for a more comprehensive example.
API Reference
- group promiscuous
Promiscuous mode support.
Functions
-
static inline struct net_pkt *net_promisc_mode_wait_data(k_timeout_t timeout)
Start to wait received network packets.
- Parameters
timeout – How long to wait before returning.
- Returns
Received net_pkt, NULL if not received any packet.
-
static inline struct net_pkt *net_promisc_mode_wait_data(k_timeout_t timeout)