1 files changed, 145 insertions, 0 deletions
diff --git a/src/arp.c b/src/arp.c
new file mode 100644
index 0000000..7ad7555
--- /dev/null
+++ b/src/arp.c
@@ -0,0 +1,145 @@
+/* 
+ * The Network Discovery Tool.
+ * Copyright (C) 2005 Tadas Vilkeliskis aka vptr (vpointer@gmail.com)
+ *
+ * The Network Discovery Tool 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 2.1 of the License, or (at your option) any later version.
+ * 
+ * This program 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 this program; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA.
+ */
+ 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netinet/ether.h>
+#include <netinet/if_ether.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netpacket/packet.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "netdt.h"
+#include "defs.h"
+#include "param.h"
+#include "iface.h"
+#include "network.h"
+
+void arp_generate_packet(struct in_addr, struct in_addr, struct ether_addr, u_int8_t *);
+
+int arp_init(int argc, char **argv)
+{
+	PDEBUG("arp_init called\n");
+	
+	extern struct param param;
+	struct in_addr sip, tip, netmask, tmp;
+	int sock_fd;
+	struct sockaddr_ll saddr_ll;
+	socklen_t sa_size = sizeof(struct sockaddr_ll);
+	struct ether_addr mac;
+	struct ether_arp *arp_header;
+	u_int8_t packet[sizeof(struct ether_header) + sizeof(struct ether_arp)];
+	//printf("%d\n", sizeof(packet)); exit(0);
+	
+	/* ETH_ALEN, ARPHDR_ETHER, ETHERTYPE_ARP */
+
+	if ( (sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ARP))) == -1) {
+		PDEBUG("ERROR: socket() failed\n");
+		fprintf(stderr, "Error: can't create socket\n");
+		exit(1);
+	}
+	if (fcntl(sock_fd, F_SETFL, O_NONBLOCK) == -1) {
+		PDEBUG("ERROR: fcntl() failed\n");
+		fprintf(stderr, "Error: can't make socket non-blocking\n");
+		close(sock_fd);
+		exit(1);
+	}
+	
+	iface_init(sock_fd, param.iface);
+
+	if ( (saddr_ll.sll_ifindex = iface_get_index()) == -1) {
+		fprintf(stderr, "Error: no such device %s\n", param.iface);
+		close(sock_fd);
+		exit(1);
+	}
+
+	/*
+	XXX
+	po situ veiksmu reiketu atlikti 
+	patikrinima ar yra teisingas IP adresas
+	*/
+	iface_get_ip(&sip);
+	iface_get_netmask(&netmask);
+	iface_get_mac(&mac);
+	
+	saddr_ll.sll_family = PF_PACKET;
+	saddr_ll.sll_halen = ETH_ALEN;
+	memset(&saddr_ll.sll_addr, 0, ETH_ALEN);
+	
+	net_calc_network(sip, netmask);
+	tip.s_addr = sip.s_addr & netmask.s_addr;
+	arp_header = (struct ether_arp*)(packet + sizeof(struct ether_header));
+	
+	fprintf(stdout, "Discovering network with %s/%s\n\n", inet_ntoa(sip), ether_ntoa(&mac));
+	
+	while ( (tip.s_addr = net_next_ip(tip)) != 0) {
+		//printf("%s\n", inet_ntoa(tip));
+		memset(packet, 0, sizeof(packet));
+		arp_generate_packet(sip, tip, mac, packet);
+		sendto(sock_fd, &packet, 42, 0, (struct sockaddr*)&saddr_ll, sizeof(struct sockaddr_ll));
+		usleep(param.packet_delay * 100);
+		if (recvfrom(sock_fd, &packet, 42, 0, (struct sockaddr*)&saddr_ll, &sa_size) == 42) {
+			if (arp_header->arp_op == htons(ARPOP_REPLY)) {
+				memcpy((void*)&tmp, (void*)&arp_header->arp_spa, 4);
+				fprintf(stdout, "%-15s %s\n", inet_ntoa(tmp),
+						ether_ntoa((struct ether_addr*)&arp_header->arp_sha));
+			}
+		}
+	}
+	return (0);
+}
+
+void arp_generate_packet(struct in_addr sip, struct in_addr tip, struct ether_addr smac, u_int8_t *packet)
+{
+	struct ether_header *eth_header;
+	struct ether_arp *arp_header;
+	
+	eth_header = (struct ether_header*)packet;
+	memset((void*)&eth_header->ether_dhost, 0xff, ETH_ALEN);	/* broadcast */
+	memcpy((void*)&eth_header->ether_shost, (void*)&smac.ether_addr_octet, ETH_ALEN);
+	eth_header->ether_type = htons(ETHERTYPE_ARP);
+	
+	arp_header = (struct ether_arp*)(packet + sizeof(struct ether_header));
+	arp_header->arp_hrd = htons(ARPHRD_ETHER);
+	arp_header->arp_pro = htons(ETHERTYPE_IP);
+	arp_header->arp_hln = ETH_ALEN;
+	arp_header->arp_pln = 4; /* reikia susiziureti ar nera kokios konstantos */
+	arp_header->arp_op = htons(ARPOP_REQUEST);
+	memcpy((void*)arp_header->arp_sha, (void*)&smac.ether_addr_octet, ETH_ALEN);
+	memcpy((void*)arp_header->arp_spa, (void*)&sip.s_addr, 4);
+	memcpy((void*)arp_header->arp_tpa, (void*)&tip.s_addr, 4);
+}
+
+void arp_usage(char *pname)
+{
+	fprintf(stderr, "The Network Discovery Tool " PROGRAM_VERSION " by " PROGRAM_AUTHOR "\n"
+			"Usage: %s arp <options>\n"
+					"Options:\n"
+					" -i <if>   Network interface\n"
+					" -t <time> Delay between packets\n"
+					" -h        Help screen\n"
+					, pname);
+	exit(0);
+}