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/*
* The ARP Scanner (arp-scan) is Copyright (C) 2005-2019 Roy Hills,
* NTA Monitor Ltd.
*
* This file is part of arp-scan.
*
* arp-scan 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.
*
* arp-scan 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 arp-scan. If not, see <http://www.gnu.org/licenses/>.
*
* link-packet-socket.c -- Packet socket link layer functions for arp-scan
*
* Author: Roy Hills
* Date: 1 July 2006
*
* Description:
*
* This contains the link layer functions using the packet socket
* implementation. Packet socket is typically used on Linux with kernel
* version 2.2 and above. See packet(7) on a Linux system for details.
*
*/
#include "arp-scan.h"
#ifdef HAVE_NETPACKET_PACKET_H
#include <netpacket/packet.h>
#endif
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif
/*
* Link layer handle structure for packet socket.
* This is typedef'ed as link_t.
*/
typedef struct link_handle {
int fd; /* Socket file descriptor */
struct ifreq ifr;
struct sockaddr_ll sll;
} link_t;
/*
* link_open -- Open the specified link-level device
*
* Inputs:
*
* device The name of the device to open
*
* Returns:
*
* A pointer to a link handle structure.
*/
static link_t *
link_open(const char *device) {
link_t *handle;
handle = Malloc(sizeof(*handle));
memset(handle, '\0', sizeof(*handle));
if ((handle->fd = socket(PF_PACKET, SOCK_RAW, 0)) < 0) {
warn_msg("ERROR: Cannot open raw packet socket");
err_sys("socket");
}
strlcpy(handle->ifr.ifr_name, device, sizeof(handle->ifr.ifr_name));
if ((ioctl(handle->fd, SIOCGIFINDEX, &(handle->ifr))) != 0)
err_sys("ioctl");
handle->sll.sll_family = PF_PACKET;
handle->sll.sll_ifindex = handle->ifr.ifr_ifindex;
handle->sll.sll_halen = ETH_ALEN;
return handle;
}
/*
* link_close -- Close the link
*
* Inputs:
*
* handle The handle for the link interface
*
* Returns:
*
* None
*/
static void
link_close(link_t *handle) {
if (handle != NULL) {
if (handle->fd != 0)
close(handle->fd);
free(handle);
}
}
/*
* get_hardware_address -- Get the Ethernet MAC address associated
* with the given device.
* Inputs:
*
* if_name The name of the network interface
* hw_address (output) the Ethernet MAC address
*
* Returns:
*
* None
*/
void
get_hardware_address(const char *if_name, unsigned char hw_address[]) {
link_t *handle;
handle = link_open(if_name);
if(!handle) {
err_sys("link_open");
return;
}
/* Obtain hardware address for specified interface */
if ((ioctl(handle->fd, SIOCGIFHWADDR, &(handle->ifr))) != 0)
err_sys("ioctl");
memcpy(hw_address, handle->ifr.ifr_ifru.ifru_hwaddr.sa_data, ETH_ALEN);
link_close(handle);
}
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