Simple program to grab statistics from OpenBSD's PF using C.

pf_to_web.c

/*
  A simple program to show how to grab statistics from OpenBSD's pf using C.
  
  gcc pf_to_web.c
  sudo ./pf_to_web
  
  Aaron Linville
  http://www.linville.org/
*/

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>
#include <netinet/in.h>
#include <net/pfvar.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
	const char *pf_device = "/dev/pf";
	int dev = -1;
	struct pf_status status;

	char statline[80], *running;
	time_t runtime;

	dev = open(pf_device, O_RDONLY);
	if (dev == -1) {
		err(1, "%s", pf_device);
	}

	if (ioctl(dev, DIOCGETSTATUS, &status)) {
		warn("DIOCGETSTATUS");
		return (-1);
	}

	runtime = time(NULL) - status.since;
	running = const_cast<char *> (status.running ? "Enabled" : "Disabled");

	if (status.since) {
		unsigned sec, min, hrs, day = runtime;

		sec = day % 60;
		day /= 60;
		min = day % 60;
		day /= 60;
		hrs = day % 24;
		day /= 24;
		snprintf(statline, sizeof(statline),
		    "Status: %s for %u days %.2u:%.2u:%.2u",
		    running, day, hrs, min, sec);
	} else {
		snprintf(statline, sizeof(statline),
		    "Status: %s", running);
	}

	printf("<p>%s</p>\n", statline);

	if (status.ifname[0] != 0) {
		printf("<p>In: %llu MB</p>\n",
		    (unsigned long long)status.bcounters[0][0] / 1024 / 1024);
		printf("<p>Out: %llu MB</p>\n",
		    (unsigned long long)status.bcounters[0][1] / 1024 / 1024);
	}

	return 0;
}