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Applicable Environment
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- Topic: How to activate promiscuous mode with io-pkt
- SDP: 6.5.0
- Target: Any supported target
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Recommendation________________________________________________________________________
With io-net network driver arguments could be used to enable
promiscuous. Since io-pkt the promiscuous is enabled on demand by the
stack. Setting up a bridge or running tcpdump (bpf utility) enables this
mode for example. Note that nicinfo maybe prints inaccurate status of
the promiscuous mode. Check the status with ifconfig instead.
This is an c-example on how to enable promiscuous mode on interface en0:
#include <string.h>
#include <stdlib.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <err.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/bpf.h>
#include <net/if.h>
int main(int argc, char *argv[])
{
int fd;
char *bpfn, *ifname;
struct ifreq ifr;
bpfn = "/dev/bpf0";
ifname = "en0";
if ((fd = open(bpfn, O_RDWR)) == -1) {
perror("open");
exit(0);
}
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, &ifr) == -1) {
perror("ioctl BIOCSETIF");
exit(0);
}
if (ioctl(fd, BIOCPROMISC, NULL) == -1) {
perror("ioctl BIOCPROMISC");
exit(0);
}
sleep(10);
close(fd);
return 0;
}
PROMISC in the ifconfig output for the en0 interface indicate that promiscuous is active.
/root# ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33192
inet 127.0.0.1 netmask 0xff000000
en0: flags=80008b43<UP,BROADCAST,RUNNING,
PROMISC,ALLMULTI,SIMPLEX,MULTICAST,SHIM
> mtu 1500
address: 00:80:ad:b7:d7:3f
media: Ethernet 100baseTX full-duplex
status: active
inet 10.42.171.102 netmask 0xffffff00 broadcast 10.42.171.255
