getifaddr.c

很小的linux下的upnp服务器端代码适合嵌入式系统

/* $Id: getifaddr.c,v 1.8 2007/10/06 10:46:25 nanard Exp $ */
/* MiniUPnP project
 * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
 * (c) 2006 Thomas Bernard 
 * This software is subject to the conditions detailed
 * in the LICENCE file provided within the distribution */

#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#if defined(sun)
#include <sys/sockio.h>
#endif

#include "getifaddr.h"

int
getifaddr(const char * ifname, char * buf, int len)
{
	/* SIOCGIFADDR struct ifreq *  */
	int s;
	struct ifreq ifr;
	int ifrlen;
	struct sockaddr_in * addr;
	ifrlen = sizeof(ifr);
	s = socket(PF_INET, SOCK_DGRAM, 0);
	if(s < 0)
	{
		syslog(LOG_ERR, "socket(PF_INET, SOCK_DGRAM): %m");
		return -1;
	}
	strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
	if(ioctl(s, SIOCGIFADDR, &ifr, &ifrlen) < 0)
	{
		syslog(LOG_ERR, "ioctl(s, SIOCGIFADDR, ...): %m");
		close(s);
		return -1;
	}
	addr = (struct sockaddr_in *)&ifr.ifr_addr;
	if(!inet_ntop(AF_INET, &addr->sin_addr, buf, len))
	{
		syslog(LOG_ERR, "inet_ntop(): %m");
		close(s);
		return -1;
	}
	close(s);
	return 0;
}