getifname.c

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/* getifname.c -- network interface handling
 * Copyright(C) 1999,2000,2001 Salvatore Sanfilippo <[e-mail]>
 * Copyright(C) 2001 by Nicolas Jombart <[e-mail]>
 * This code is under the GPL license */

/* BSD support thanks to Nicolas Jombart <[e-mail]> */

#include <stdio.h>		/* perror */
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>		/* struct sockaddr_in */
#include <arpa/inet.h>		/* inet_ntoa */
#include <net/if.h>
#include <unistd.h>		/* close */

#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
#include <stdlib.h>
#include <ifaddrs.h>
#include <net/route.h>
#include <net/if_dl.h> 
#endif /* defined(__*BSD__) */

#include "hping2.h"
#include "globals.h"

#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__linux__) && !defined(__sun__)
#error Sorry, interface code not implemented.
#endif

#ifdef __sun__
#include <sys/sockio.h>
#include <net/route.h>
#include <net/if_dl.h>
#endif

#if (defined __linux__) || (defined __sun__)
static int get_output_if(struct sockaddr_in *dest, struct sockaddr_in *ifip);
#endif

#if (defined OSTYPE_LINUX) || (defined __sun__)
int get_if_name(void)
{
	int fd;
	struct ifconf	ifc;
	struct ifreq	ibuf[16],
			ifr,
			*ifrp,
			*ifend;
	struct sockaddr_in sa;
	struct sockaddr_in output_if_addr;
	int known_output_if = 0;

	/* Try to get the output interface address according to
	 * the OS routing table */
	if (ifname[0] == '\0') {
		if (get_output_if(&remote, &output_if_addr) == 0) {
			known_output_if = 1;
			if (opt_debug)
				printf("Output interface address: %s\n",
					inet_ntoa(sa.sin_addr));
		} else {
			fprintf(stderr, "Warning: Unable to guess the output "
					"interface\n");
		}
	}

	if ( (fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
		perror("[get_if_name] socket(AF_INET, SOCK_DGRAM, 0)");
		return -1;
	}

	memset(ibuf, 0, sizeof(struct ifreq)*16);
	ifc.ifc_len = sizeof ibuf;
	ifc.ifc_buf = (caddr_t) ibuf;

	/* gets interfaces list */
	if ( ioctl(fd, SIOCGIFCONF, (char*)&ifc) == -1 ||
	     ifc.ifc_len < sizeof(struct ifreq)		) {
		perror("[get_if_name] ioctl(SIOCGIFCONF)");
		close(fd);
		return -1;
	}

	/* ifrp points to buffer and ifend points to buffer's end */
	ifrp = ibuf;
	ifend = (struct ifreq*) ((char*)ibuf + ifc.ifc_len);

	for (; ifrp < ifend; ifrp++) {
		strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));

		if ( ioctl(fd, SIOCGIFFLAGS, (char*)&ifr) == -1) {
			if (opt_debug)
				perror("[get_if_name] ioctl(SIOCGIFFLAGS)");
			continue;
		}

		if (opt_debug)
			printf("if %s: ", ifr.ifr_name);

		/* Down interface? */
		if ( !(ifr.ifr_flags & IFF_UP) )
		{
			if (opt_debug)
				printf("DOWN\n");
			continue;
		}

		if (known_output_if) {
			/* Get the interface address */
			if (ioctl(fd, SIOCGIFADDR, (char*)&ifr) == -1) {
				perror("[get_if_name] ioctl(SIOCGIFADDR)");
				continue;
			}
			/* Copy it */
			memcpy(&sa, &ifr.ifr_addr,
				sizeof(struct sockaddr_in));
			/* Check if it is what we are locking for */
			if (sa.sin_addr.s_addr !=
			    output_if_addr.sin_addr.s_addr) {
				if (opt_debug)
					printf("The address doesn't match\n");
				continue;
			}
		} else if (ifname[0] != '\0' && !strstr(ifr.ifr_name, ifname)) {
			if (opt_debug)
				printf("Don't Match (but seems to be UP)\n");
			continue;
		}

		if (opt_debug)
			printf("OK\n");

		/* interface found, save if name */
		strncpy(ifname, ifr.ifr_name, 1024);

		/* get if address */
		if ( ioctl(fd, SIOCGIFADDR, (char*)&ifr) == -1) {
			perror("[get_if_name] ioctl(SIOCGIFADDR)");
			exit(1);
		}

		/* save if address */
		memcpy(&sa, &ifr.ifr_addr,
			sizeof(struct sockaddr_in));
		strncpy(ifstraddr, inet_ntoa(sa.sin_addr), 1024);

		/* get if mtu */
		if ( ioctl(fd, SIOCGIFMTU, (char*)&ifr) == -1) {
			perror("Warning: [get_if_name] ioctl(SIOCGIFMTU)");
			fprintf(stderr, "Using a fixed MTU of 1500\n");
			h_if_mtu = 1500;
		}
		else
		{
#ifdef __sun__
			/* somehow solaris is braidamaged in wrt ifr_mtu */
			h_if_mtu = ifr.ifr_metric;
#else
			h_if_mtu = ifr.ifr_mtu;
#endif
		}
		close(fd);
		return 0;
	}
	/* interface not found, use 'lo' */
	strncpy(ifname, "lo", 1024);
	strncpy(ifstraddr, "127.0.0.1", 1024);
	h_if_mtu = 1500;

	close(fd);
	return 0;
}

#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)

/* *BSD code written by Nicolas Jombart <[e-mail]> 
   Version: 4
*/

#define BUFLEN  (sizeof(struct rt_msghdr) + 512)

/* from Stevens' Unix Network Programming */
#define ROUNDUP(a, size) (((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
#define NEXT_SA(ap)     ap = (struct sockaddr *) \
        ((caddr_t) ap + (ap->sa_len ? ROUNDUP(ap->sa_len, sizeof (u_long)) : \
                                                                sizeof(u_long)))
static void
get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
{
        int             i;

        for (i = 0; i < RTAX_MAX; i++) {
                if (addrs & (1 << i)) {
                        rti_info[i] = sa;
                        NEXT_SA(sa);
                } else
                        rti_info[i] = NULL;
        }
}

/* get GW. return 1 if IP address of the gateway, 2 if interface address */
static int get_gw(char *target, char *address) {
int 		 	fd,pid,n;
char 		 	*buf;
struct rt_msghdr 	*rtm;
struct sockaddr_in 	*sin;
struct sockaddr		*sa,*rti_info[RTAX_MAX];

	/* bad hack if loopback interface */
	if(!strncmp(target,"127.0.0.1",9))
	{
		strncpy(address,"lo0\0",4);
		return 2;
	}

	/* try first to get interface from the kernel internal routing table */
	if( (fd = socket(PF_ROUTE,SOCK_RAW,0)) < 0) {
		perror("Can't open routing socket.\n");
		exit(1);
	}

	buf = (char *)calloc(1, BUFLEN);
	rtm = (struct rt_msghdr *) buf;
		
	/* data structure to talk with the kernel */
	rtm->rtm_msglen = sizeof(struct rt_msghdr) + sizeof(struct sockaddr_in);
	rtm->rtm_version = RTM_VERSION;
	rtm->rtm_type = RTM_GET;     
	rtm->rtm_addrs = RTA_DST;    /* socket address structure contains destination address */
	rtm->rtm_pid = pid = getpid();
	rtm->rtm_seq = 9999;

	sin = (struct sockaddr_in *) (rtm + 1);
	sin->sin_len = sizeof(struct sockaddr_in); sin->sin_family = AF_INET;
	inet_pton(AF_INET, target ,&sin->sin_addr);
	if (opt_debug) printf("adresse