linux interface counter for bps pps

ifc.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <linux/rtnetlink.h>

#define INTFMAX	16

struct link_stats {
	char  * ifname;
	struct rtnl_link_stats * stats;
};


int
get_link_stats (char * buf, size_t len, struct link_stats * stats)
{
	int fd, n, i;
	struct sockaddr_nl sa;
	struct nlmsghdr * nlh;
	struct ifinfomsg * ifi;
	struct {
		struct nlmsghdr	nlh;
		struct ifinfomsg  ifi;
	} req;


	fd = socket (AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
	if (fd < 0) {
		perror ("sock");
		return -1;
	}

	memset (&sa, 0, sizeof (sa));
	sa.nl_family	= AF_NETLINK;
	sa.nl_pid	= 0;
	sa.nl_groups	= 0;

	memset (&req, 0, sizeof (req));
	req.nlh.nlmsg_len	= sizeof (req);
	req.nlh.nlmsg_type	= RTM_GETLINK;
	req.nlh.nlmsg_flags	= NLM_F_ROOT | NLM_F_REQUEST;
	req.nlh.nlmsg_pid	= 0;
	req.nlh.nlmsg_seq	= 100;
	req.ifi.ifi_family	= ARPHRD_ETHER;

	n = sendto (fd, &req, sizeof (req), 0,
		    (struct sockaddr *) &sa, sizeof (sa));

	if (n < 0) {
		perror ("sendto");
		close (fd);
		return -1;
	}

	n = recv (fd, buf, len, 0);
	if (n < 0) {
		perror ("recv");
		close (fd);
		return -1;
	}

	i = 0;
	for (nlh = (struct nlmsghdr *) buf; NLMSG_OK (nlh, n);
	     nlh = NLMSG_NEXT (nlh, n)) {
		
		int rtalist_len;
		struct rtattr * rta;

		if (nlh->nlmsg_type != RTM_NEWLINK) {
			printf ("invalid nlmsg_type : %d\n", nlh->nlmsg_type);
			continue;
		}

		ifi = NLMSG_DATA (nlh);
		rtalist_len = nlh->nlmsg_len - 
			NLMSG_LENGTH (sizeof (struct ifinfomsg));

		for (rta = IFLA_RTA (ifi); RTA_OK (rta, rtalist_len);
		     rta = RTA_NEXT (rta, rtalist_len)) {

			switch (rta->rta_type) {
			case IFLA_IFNAME :
				stats[i].ifname = RTA_DATA (rta);
				break;

			case IFLA_STATS :
				stats[i].stats = RTA_DATA (rta);
				break;
			}

		}

		if (INTFMAX - 1 < ++i) 
			break;
	}

	close (fd);

	return 1;
}

struct link_stats *
find_stats_by_name (struct link_stats * stats, char * ifname)
{
	int n;

	for (n = 0; n < INTFMAX && stats[n].ifname != NULL; n++) {
		if (strncmp (stats[n].ifname, ifname, IFNAMSIZ) == 0)
			return &stats[n];
	}

	return NULL;
}

int
main (int argc, char ** argv)
{
	int n;
	char buf1[8192], buf2[8192], * prefix = "";
	struct link_stats * sts, sts1[INTFMAX], sts2[INTFMAX];
	struct timeval tv1, tv2;
	
	memset (buf1, 0, sizeof (buf1));
	memset (buf2, 0, sizeof (buf2));
	memset (sts1, 0, sizeof (sts1));
	memset (sts2, 0, sizeof (sts2));

	if (argc > 1) 
		prefix = argv[1];
	gettimeofday (&tv1, NULL);
	get_link_stats (buf1, sizeof (buf1), sts1);

	sleep (1);

	gettimeofday (&tv2, NULL);
	get_link_stats (buf2, sizeof (buf2), sts2);

	for (n = 0; n < INTFMAX && sts2[n].ifname != NULL; n++) {
		unsigned int txpps, rxpps, txbps, rxbps;

		sts = find_stats_by_name (sts1, sts2[n].ifname);
		if (!sts)
			continue;

		txpps = sts2[n].stats->tx_packets - sts->stats->tx_packets;
		rxpps = sts2[n].stats->rx_packets - sts->stats->rx_packets;
		txbps = (sts2[n].stats->tx_bytes - sts->stats->tx_bytes) * 8;
		rxbps = (sts2[n].stats->rx_bytes - sts->stats->rx_bytes) * 8;
		
		printf ("%s: %s: txpps:%u rxpps:%u txbps:%u rxbps:%u\n",
			prefix, sts2[n].ifname,
			txpps, rxpps, txbps, rxbps);
	}
	

	return 0;
}