ipconfig/netdev.c

/*
 * ipconfig/netdev.c
 *
 * ioctl-based device configuration
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <linux/route.h>

#include "netdev.h"

static int cfd = -1;

static void copy_name(struct netdev *dev, struct ifreq *ifr)
{
	strncpy(ifr->ifr_name, dev->name, sizeof(ifr->ifr_name));
	ifr->ifr_name[sizeof(ifr->ifr_name) - 1] = '\0';
}

int netdev_getflags(struct netdev *dev, short *flags)
{
	struct ifreq ifr;

	copy_name(dev, &ifr);

	if (ioctl(cfd, SIOCGIFFLAGS, &ifr) == -1) {
		perror("SIOCGIFFLAGS");
		return -1;
	}

	*flags = ifr.ifr_flags;
	return 0;
}

static int netdev_sif_addr(struct ifreq *ifr, int cmd, __u32 addr)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr->ifr_addr;

	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = addr;

	return ioctl(cfd, cmd, ifr);
}

int netdev_setaddress(struct netdev *dev)
{
	struct ifreq ifr;

	copy_name(dev, &ifr);

	if (dev->ip_addr != INADDR_ANY &&
	    netdev_sif_addr(&ifr, SIOCSIFADDR, dev->ip_addr) == -1) {
		perror("SIOCSIFADDR");
		return -1;
	}

	if (dev->ip_broadcast != INADDR_ANY &&
	    netdev_sif_addr(&ifr, SIOCSIFBRDADDR, dev->ip_broadcast) == -1) {
		perror("SIOCSIFBRDADDR");
		return -1;
	}

	if (dev->ip_netmask != INADDR_ANY &&
	    netdev_sif_addr(&ifr, SIOCSIFNETMASK, dev->ip_netmask) == -1) {
		perror("SIOCSIFNETMASK");
		return -1;
	}

	return 0;
}

int netdev_setdefaultroute(struct netdev *dev)
{
	struct rtentry r;

	if (dev->ip_gateway == INADDR_ANY)
		return 0;

	memset(&r, 0, sizeof(r));

	((struct sockaddr_in *)&r.rt_dst)->sin_family = AF_INET;
	((struct sockaddr_in *)&r.rt_dst)->sin_addr.s_addr = INADDR_ANY;
	((struct sockaddr_in *)&r.rt_gateway)->sin_family = AF_INET;
	((struct sockaddr_in *)&r.rt_gateway)->sin_addr.s_addr = dev->ip_gateway;
	((struct sockaddr_in *)&r.rt_genmask)->sin_family = AF_INET;
	((struct sockaddr_in *)&r.rt_genmask)->sin_addr.s_addr = INADDR_ANY;
	r.rt_flags = RTF_UP | RTF_GATEWAY;

	if (ioctl(cfd, SIOCADDRT, &r) == -1 && errno != EEXIST) {
		perror("SIOCADDRT");
		return -1;
	}
	return 0;
}

int netdev_setmtu(struct netdev *dev)
{
	struct ifreq ifr;

	copy_name(dev, &ifr);
	ifr.ifr_mtu = dev->mtu;

	return ioctl(cfd, SIOCSIFMTU, &ifr);
}	

static int netdev_gif_addr(struct ifreq *ifr, int cmd, __u32 *ptr)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr->ifr_addr;

	if (ioctl(cfd, cmd, ifr) == -1)
		return -1;

	*ptr = sin->sin_addr.s_addr;

	return 0;
}

int netdev_up(struct netdev *dev)
{
	struct ifreq ifr;

	copy_name(dev, &ifr);

	if (ioctl(cfd, SIOCGIFFLAGS, &ifr) == -1) {
		perror("SIOCGIFFLAGS");
		return -1;
	}

	ifr.ifr_flags |= IFF_UP;

	if (ioctl(cfd, SIOCSIFFLAGS, &ifr) == -1) {
		perror("SIOCSIFFLAGS");
		return -1;
	}
	return 0;
}

int netdev_down(struct netdev *dev)
{
	struct ifreq ifr;

	copy_name(dev, &ifr);

	if (ioctl(cfd, SIOCGIFFLAGS, &ifr) == -1) {
		perror("SIOCGIFFLAGS");
		return -1;
	}

	ifr.ifr_flags &= ~IFF_UP;

	if (ioctl(cfd, SIOCSIFFLAGS, &ifr) == -1) {
		perror("SIOCSIFFLAGS");
		return -1;
	}
	return 0;
}

int netdev_init_if(struct netdev *dev)
{
	struct ifreq ifr;

	if (cfd == -1)
		cfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (cfd == -1) {
		perror("socket(AF_INET)");
		return -1;
	}

	copy_name(dev, &ifr);

	if (ioctl(cfd, SIOCGIFINDEX, &ifr) == -1) {
		perror("SIOCGIFINDEX");
		return -1;
	}

	dev->ifindex = ifr.ifr_ifindex;

	if (ioctl(cfd, SIOCGIFMTU, &ifr) == -1) {
		perror("SIOCGIFMTU");
		return -1;
	}

	dev->mtu = ifr.ifr_mtu;

	if (ioctl(cfd, SIOCGIFHWADDR, &ifr) == -1) {
		perror("SIOCGIFHWADDR");
		return -1;
	}

	dev->hwtype = ifr.ifr_hwaddr.sa_family;
	dev->hwlen  = 0;

	switch (dev->hwtype) {
	case ARPHRD_ETHER:
		dev->hwlen = 6;
		break;
	case ARPHRD_EUI64:
		dev->hwlen = 8;
		break;
	case ARPHRD_LOOPBACK:
		dev->hwlen = 0;
		break;
	default:
		return -1;
	}

	memcpy(dev->hwaddr, ifr.ifr_hwaddr.sa_data, dev->hwlen);
	memset(dev->hwbrd, 0xff, dev->hwlen);

	/*
	 * Try to get the current interface information.
	 */
	if (dev->ip_addr == INADDR_NONE &&
	    netdev_gif_addr(&ifr, SIOCGIFADDR, &dev->ip_addr) == -1) {
		perror("SIOCGIFADDR");
		dev->ip_addr = 0;
		dev->ip_broadcast = 0;
		dev->ip_netmask = 0;
		return 0;
	}

	if (dev->ip_broadcast == INADDR_NONE &&
	    netdev_gif_addr(&ifr, SIOCGIFBRDADDR, &dev->ip_broadcast) == -1) {
		perror("SIOCGIFBRDADDR");
		dev->ip_broadcast = 0;
	}

	if (dev->ip_netmask == INADDR_NONE &&
	    netdev_gif_addr(&ifr, SIOCGIFNETMASK, &dev->ip_netmask) == -1) {
		perror("SIOCGIFNETMASK");
		dev->ip_netmask = 0;
	}

	return 0;
}