generate_if_map.c

/*
 * Gatekeeper - DoS protection system.
 * Copyright (C) 2016 Digirati LTDA.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define GATEKEEPER_IF_MAP	"./lua/if_map.lua"

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/ethtool.h> 
#include <linux/sockios.h>

int
main(void)
{
	FILE *f;
	struct ifaddrs *addrs, *iter;
	int sock;
	int ret;

	f = fopen(GATEKEEPER_IF_MAP, "w");
	if (f == NULL) {
		perror("fopen");
		return -1;
	}

	ret = getifaddrs(&addrs);
	if (ret == -1) {
		perror("getifaddrs");
		goto file;
	}

	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock == -1) {
		perror("socket");
		goto addrs;
	}

	fprintf(f, "return {\n");

	iter = addrs;
	while (iter != NULL) {
		struct ifreq ifr;
		struct ethtool_cmd cmd;
		struct ethtool_drvinfo drvinfo;

		/*
		 * Use AF_PACKET to only get each interface once,
		 * and skip the loopback interface.
		 */
		if (iter->ifa_addr == NULL ||
				iter->ifa_addr->sa_family != AF_PACKET ||
				strcmp(iter->ifa_name, "lo") == 0)
			goto next;

		memset(&ifr, 0, sizeof(ifr));
		memset(&cmd, 0, sizeof(cmd));
		memset(&drvinfo, 0, sizeof(drvinfo));
		strcpy(ifr.ifr_name, iter->ifa_name);

		ifr.ifr_data = (void *)&drvinfo;
		drvinfo.cmd = ETHTOOL_GDRVINFO;

		if (ioctl(sock, SIOCETHTOOL, &ifr) < 0) {
			perror("ioctl");
			goto next;
		}

		fprintf(f, "\t[\"%s\"] = \"%s\",\n", iter->ifa_name,
			drvinfo.bus_info);
next:
		iter = iter->ifa_next;
	}

	fprintf(f, "}\n");

	close(sock);
addrs:
	freeifaddrs(addrs);
file:
	fclose(f);
	return ret;
}