/*
* Mausezahn - A fast versatile traffic generator
* Copyright (C) 2008-2010 Herbert Haas
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*
* 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, see http://www.gnu.org/licenses/gpl-2.0.html
*
*/
#include "mz.h"
#include "mops.h"
#include <netpacket/packet.h>
#include <netinet/ether.h>
// PURPOSE: Find usable network devices
//
// NOTE:
//
// 1. Ignores devices without IP address
// 2. Ignores loopback (etc)
//
// RETURN VALUES:
//
// 0 if usable device found (device_list[] and tx.device set)
// 1 if no usable device found
//
int lookupdev(void)
{
// char *tx.device is global, see as.h
char
ipaddress[IPADDRSIZE+1],
errbuf[PCAP_ERRBUF_SIZE];
pcap_if_t
*alldevs,
*index = NULL;
pcap_addr_t *pcap_addr;
int i=0;
// FIRST get a list of all available devices
//
if (pcap_findalldevs(&alldevs, errbuf) == -1)
{
fprintf(stderr," mz: %s\n",errbuf);
return 1;
}
index = (pcap_if_t *) alldevs;
while (index)
{
if (index->addresses)
{
pcap_addr = index->addresses;
while(pcap_addr)
{
if (pcap_addr->addr && (pcap_addr->addr->sa_family==AF_INET))
{
if (inet_ntop(pcap_addr->addr->sa_family,
(void *)&pcap_addr->addr->sa_data[2],
ipaddress,
IPADDRSIZE))
{
if (verbose)
{
fprintf(stderr," mz: device %s got assigned %s ",
index->name, ipaddress);
}
if (strncmp(ipaddress, "127", 3)==0)
{
if (verbose) fprintf(stderr, "(loopback)\n");
strncpy(device_list[i].dev, index->name, 9);
strncpy(device_list[i].ip_str, ipaddress, IPADDRSIZE);
device_list[i].phy=0;
get_if_addr(index->name, device_list[i].ip, device_list[i].mac);
get_if_addr(index->name, device_list[i].ip_mops, device_list[i].mac_mops);
i++;
}
else if (strncmp(ipaddress, "169.254", 7)==0)
{
if (verbose) fprintf(stderr, "but IGNORED (cause: host-scope address)\n");
}
else // FOUND VALID INTERFACE
{
if (verbose) fprintf(stderr, "and is a possible candidate.\n");
strncpy(device_list[i].dev, index->name, 9);
strncpy(device_list[i].ip_str, ipaddress, IPADDRSIZE);
device_list[i].phy=1;
get_if_addr(index->name, device_list[i].ip, device_list[i].mac);
get_if_addr(index->name, device_list[i].ip_mops, device_list[i].mac_mops);
i++;
}
// Select only interfaces with IP addresses
// but avoid those that start with 127 or 169.254
// Put the remaining on a list. If this list has more than one entry
// ask the user which interface to listen to.
}
else
{
return 1;
}
}
pcap_addr = pcap_addr->next;
} // closes while(pcap_addr)
}
index = index->next;
} // closes while (index)
device_list_entries = i;
/*
if (verbose)
{
for (i=0; i<device_list_entries; i++)
{
fprintf(stderr, " mz: Found device %s with IP %s\n", device_list[i].dev, device_list[i].ip_str);
}
}
*/
// No device found:
if (device_list_entries==0) return 1;
// Else device found:
// initialize tx.device with first entry of the device_list
strncpy (tx.device, device_list[0].dev, 16);
return 0;
}
// Determines ip and mac address of specified interface 'ifname'
// Caller must provide an unsigned char ip[4], mac[6]
//
int get_if_addr (char *ifname, u_int8_t *ip, u_int8_t *mac)
{
int fd, i;
struct ifreq ifr;
struct sockaddr_in saddr;
u_int8_t *x;
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, ifname , IFNAMSIZ-1);
// we must open a socket to get the addresses
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd == -1) return 1;
// get mac
ioctl(fd, SIOCGIFHWADDR, &ifr);
for (i=0; i<6; i++) mac[i]= (u_int8_t) ifr.ifr_hwaddr.sa_data[i];
// get IP
ioctl(fd, SIOCGIFADDR, &ifr);
saddr=*((struct sockaddr_in *)(&(ifr.ifr_addr)));
x = (u_int8_t*)&saddr.sin_addr;
ip[0]=*x; ip[1]=*(x+1); ip[2]=*(x+2); ip[3]=*(x+3);
close(fd);
return 0;
}
// For a given device name, find out the following parameters:
//
// - MTU
// - Network
// - Mask
// - Default GW (IP)
// - Default GW (MAC)
// - Open packet socket (if not already done)
//
int get_dev_params (char *name)
{
FILE *fd;
char f[10][16], line[256];
int in=0, nw=1, gw=2, mk=7; // default columns in /proc/net/route for interface, network, gateway, and mask.
unsigned int tmp[4], net[4]={0,0,0,0}, dgw[4], mask[4]={0,0,0,0};
int i=0, flag=0, nw_found=0, gw_found=0, devind=0, dev_found=0;
struct ifreq si;
struct sockaddr_ll psock;
int ps, index, mtu;
struct arp_table_struct *cur;
// 1. Check if device is already present in our device_list
for (i=0; i<device_list_entries; i++) {
if (strncmp(device_list[i].dev, name, 16)==0) {
devind=i;
dev_found=1;
break;
}
}
if (dev_found==0) return 1; // ERROR: device name not found !!!!
// 2. find network, gateway, and mask
fd = fopen("/proc/net/route", "r");
while (fgets(line, 255, fd)!=NULL) {
sscanf(line, " %s %s %s %s %s %s %s %s %s %s", f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
if (!flag) { // find columns (we do NOT assume that the order of columns is the same everywhere)
for (i=0; i<10; i++) {
if (strncasecmp(f[i],"iface", 16)==0) in=i;
if (strncasecmp(f[i],"destination", 16)==0) nw=i;
if (strncasecmp(f[i],"gateway", 16)==0) gw=i;
if (strncasecmp(f[i],"mask", 16)==0) mk=i;
}
flag=1;
}
if (strncmp(f[in], name, 16)==0) { // interface found
// Determine network
if ((strncmp(f[nw],"00000000",8)!=0) && (strncmp(f[gw],"00000000",8)==0)) {
// ignore 169.254 and 127 networks
sscanf(f[nw],"%02x%02x%02x%02x",&tmp[3], &tmp[2], &tmp[1], &tmp[0]);
if ((tmp[0]!=127) && (tmp[0]!=169)) {
nw_found=1;
net[0]=tmp[0];
net[1]=tmp[1];
net[2]=tmp[2];
net[3]=tmp[3];
// also get mask for that network
sscanf(f[mk],"%02x%02x%02x%02x",&tmp[3], &tmp[2], &tmp[1], &tmp[0]);
mask[0]=tmp[0];
mask[1]=tmp[1];
mask[2]=tmp[2];
mask[3]=tmp[3];
}
}
// Determine gateway
if ((strncmp(f[nw],"00000000",8)==0) && (strncmp(f[gw],"00000000",8)!=0)) {
sscanf(f[gw],"%02x%02x%02x%02x",&dgw[3], &dgw[2], &dgw[1], &dgw[0]);
gw_found=1;
}
}
}
fclose(fd);
// 3. Get device index, determine MTU,
// and bind socket to device for later TX and RX
// if socket is already open, then close and re-open it!
if (device_list[devind].ps>=0) {
close(device_list[devind].ps);
device_list[devind].ps=-1;
}
if (device_list[devind].ps<0) {
ps = socket (PF_PACKET, SOCK_RAW, htons(ETH_P_IP)); //ETH_P_ALL, ETH_P_802_3);
if (ps<0) {
fprintf(stderr, " Warning: [lookupdev.c get_dev_params()] Cannot open socket!\n");
return 1;
}
// Get device index
strncpy(si.ifr_name, name, IFNAMSIZ);
if (ioctl(ps, SIOCGIFINDEX, &si)==-1) {
perror("ioctl");
close(ps);
return 1;
}
index=si.ifr_ifindex;
// Get MTU
if (ioctl(ps, SIOCGIFMTU, &si)==-1) {
perror("ioctl");
close(ps);
return 1;
}
mtu = si.ifr_mtu;
// ***** bind socket for later TX and RX ****
psock.sll_family = AF_PACKET; // evident
// psock.sll_protocol = 0; // unsigned short - Physical layer protocol
psock.sll_ifindex = index; // int - Interface number
psock.sll_hatype = 0; // unsigned short - Header type //ARPHRD_ETHER
psock.sll_pkttype = 0; // unsigned char - Packet type
psock.sll_halen = 6; // unsigned char - Length of address
bind(ps, (const struct sockaddr *) &psock, sizeof(psock)); // <= !!!
device_list[devind].ps = ps; // Note that close(ps) must be done upon termination
}
// Get MAC of default gateway
service_arp(name, device_list[devind].ip_gw, device_list[devind].mac_gw);
usleep(200); // this is a VERY short delay but it usually works in today's LANs
cur=device_list[devind].arp_table;
while(cur!=NULL) {
if ((cur->sip[0]==dgw[0]) &&
(cur->sip[1]==dgw[1]) &&
(cur->sip[2]==dgw[2]) &&
(cur->sip[3]==dgw[3])) { // entry found!
for (i=0; i<6; i++) {
device_list[devind].mac_gw[i] = cur->smac[i];
}
}
cur=cur->next;
}
// FINALLY: Copy findings in device_list
if (device_list[devind].phy) {
for (i=0; i<4; i++) {
device_list[devind].net[i] = net[i];
device_list[devind].mask[i] = mask[i];
device_list[devind].ip_gw[i] = dgw[i];
}
}
else {
for (i=0; i<4; i++) {
device_list[devind].net[i] = 0;
device_list[devind].mask[i] = 0;
device_list[devind].ip_gw[i] = 0;
}
}
device_list[devind].index = index;
device_list[devind].mtu = mtu;
return 0;
}