/** arping/src/arping.c
*
* arping
*
* By Thomas Habets <thomas@habets.se>
*
* ARP 'ping' utility
*
* Broadcasts a who-has ARP packet on the network and prints answers.
* *VERY* useful when you are trying to pick an unused IP for a net that
* you don't yet have routing to. Then again, if you have no idea what I'm
* talking about then you prolly don't need it.
*
* Also finds out IP of specified MAC.
*
*/
/*
* Copyright (C) 2000-2014 Thomas Habets <thomas@habets.se>
*
* This program 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 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <math.h>
#include <poll.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDINT_H
#include <stdint.h>
#endif
#if HAVE_INTTYPES_H
#include <inttypes.h>
#endif
#if HAVE_TIME_H
#include <time.h>
#endif
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if HAVE_LIBNET_H
#include <libnet.h>
#endif
#if HAVE_WIN32_LIBNET_H
#include <win32/libnet.h>
#endif
#if HAVE_PWD_H
#include <pwd.h>
#endif
#if HAVE_SYS_CAPABILITY_H
#include <sys/capability.h>
#endif
#if HAVE_NET_BPF_H
#include <net/bpf.h>
#endif
#include <pcap.h>
#include "arping.h"
#ifndef ETH_ALEN
#define ETH_ALEN 6
#endif
#ifndef IP_ALEN
#define IP_ALEN 4
#endif
#ifndef WIN32
#define WIN32 0
#endif
#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC CLOCK_REALTIME
#endif
/**
* OS-specific interface finding using routing table. See findif_*.c
* ebuf must be called with a size of at least
* max(LIBNET_ERRBUF_SIZE, PCAP_ERRBUF_SIZE).
*/
const char *
arping_lookupdev(uint32_t srcip, uint32_t dstip, char *ebuf);
const char *
arping_lookupdev_default(uint32_t srcip, uint32_t dstip, char *ebuf);
static const char *version = VERSION; /* from autoconf */
static libnet_t *libnet = 0;
/* Timestamp of last packet sent.
* Used for timing, and assumes that reply is due to most recent sent query.
*/
static struct timespec lastpacketsent;
/* target string */
static char *target = "huh? bug in arping?";
/*
* Ping IP mode: cmdline target
* Ping MAC mode: 255.255.255.255, override with -T
*/
static uint32_t dstip;
/*
* Ping IP mode: ethxmas, override with -t
* Ping MAC mode: cmdline target
*/
static uint8_t dstmac[ETH_ALEN];
static uint32_t srcip; /* autodetected, override with -S/-b/-0 */
static uint8_t srcmac[ETH_ALEN]; /* autodetected, override with -s */
static int beep = 0; /* beep when reply is received. -a */
static int reverse_beep = 0; /* beep when expected reply absent. -e */
static int alsototal = 0; /* print sent as well as received. -u */
static int addr_must_be_same = 0; /* -A */
static int unsolicited = 0; /* -U */
static int send_reply = 0; /* Send reply instead of request. -P */
static int finddup = 0; /* finddup mode. -d */
static int dupfound = 0; /* set to 1 if dup found */
static char lastreplymac[ETH_ALEN]; /* if last different from this then dup */
static unsigned int numsent = 0; /* packets sent */
static unsigned int numrecvd = 0; /* packets received */
static unsigned int max_replies = UINT_MAX; /* exit after -C replies */
static unsigned int numdots = 0; /* dots that should be printed */
static const char* timestamp_type = NULL; /* Incoming packet measurement ts type (-m) */
static double stats_min_time = -1;
static double stats_max_time = -1;
static double stats_total_time = 0;
static double stats_total_sq_time = 0;
/* RAWRAW is RAW|RRAW */
static enum { NORMAL, /* normal output */
QUIET, /* No output. -q */
RAW, /* Print MAC when pinging IP. -r */
RRAW, /* Print IP when pinging IP. -R */
RAWRAW, /* Print both. -r and -R */
DOT /* Print '.' and '!', Cisco-style. -D */
} display = NORMAL;
static const uint8_t ethnull[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
static const uint8_t ethxmas[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
int verbose = 0; /* Increase with -v */
/* Doesn't really need to be volatile, but doesn't hurt. */
static volatile sig_atomic_t time_to_die = 0;
/**
* If possible, chroot.
*
* The sshd user is used for privilege separation in OpenSSH.
* Let's assume it's installed and chroot() to there.
*/
static void
drop_fs_root()
{
const char* chroot_user = "sshd";
struct passwd *pw;
errno = 0;
if (!(pw = getpwnam(chroot_user))) {
if (verbose) {
printf("arping: getpwnam(%s): %s",
chroot_user, strerror(errno));
}
return;
}
if (chdir(pw->pw_dir)) {
if (verbose) {
printf("arping: chdir(%s): %s",
pw->pw_dir, strerror(errno));
}
return;
}
if (chroot(pw->pw_dir)) {
if (verbose) {
printf("arping: chroot(%s): %s",
pw->pw_dir, strerror(errno));
}
return;
}
if (verbose > 1) {
printf("arping: Successfully chrooted to %s\n", pw->pw_dir);
}
}
/**
* If possible, drop uid to nobody.
*
* This code only successfully sets all [ug]ids if running as
* root. ARPing is most likely running as root unless using
* capabilities, and those are dropped elsewhere.
*/
static void
drop_uid(uid_t uid, gid_t gid)
{
int fail = 0;
if (setgroups(0, NULL)) {
if (verbose) {
printf("arping: setgroups(0, NULL): %s\n", strerror(errno));
}
fail++;
}
if (gid && setgid(gid)) {
if (verbose) {
printf("arping: setgid(): %s\n", strerror(errno));
}
fail++;
}
if (uid && setuid(uid)) {
if (verbose) {
printf("arping: setuid(): %s\n", strerror(errno));
}
fail++;
}
if (!fail && verbose > 1) {
printf("arping: Successfully dropped uid/gid to %d/%d.\n",
uid, gid);
}
}
/**
* Drop any and all capabilities.
*/
static void
drop_capabilities()
{
#if HAVE_CAP_INIT
cap_t no_cap;
if (!(no_cap = cap_init())) {
if (verbose) {
printf("arping: cap_init(): %s\n", strerror(errno));
}
return;
}
if (cap_set_proc(no_cap)) {
if (verbose) {
printf("arping: cap_set_proc(): %s\n", strerror(errno));
}
}
if (verbose > 1) {
printf("arping: Successfully dropped all capabilities.\n");
}
cap_free(no_cap);
#endif
}
/**
* drop all privileges.
*/
static void
drop_privileges()
{
// Need to get uid/gid of 'nobody' before chroot().
const char* drop_user = "nobody";
struct passwd *pw;
errno = 0;
uid_t uid = 0;
gid_t gid = 0;
if (!(pw = getpwnam(drop_user))) {
if (verbose) {
printf("arping: getpwnam(%s): %s\n",
drop_user, strerror(errno));
}
return;
} else {
uid = pw->pw_uid;
gid = pw->pw_gid;
}
drop_fs_root();
drop_uid(uid, gid);
drop_capabilities();
}
/**
* Do pcap_open_live(), except by using the pcap_create() interface
* introduced in 2008 (libpcap 0.4) where available.
*
* FIXME: Use pcap_set_buffer_size()?
*/
static pcap_t*
try_pcap_open_live(const char *device, int snaplen,
int promisc, int to_ms, char *errbuf)
{
#ifdef HAVE_PCAP_CREATE
pcap_t* pcap;
int rc;
if (!(pcap = pcap_create(device, errbuf))) {
goto err;
}
if ((rc = pcap_set_snaplen(pcap, snaplen))) {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "pcap_set_snaplen(): %s", pcap_statustostr(rc));
goto err;
}
if ((rc = pcap_set_promisc(pcap, promisc))) {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "pcap_set_promisc(): %s", pcap_statustostr(rc));
goto err;
}
if ((rc = pcap_set_timeout(pcap, to_ms))) {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "pcap_set_timeout(): %s", pcap_statustostr(rc));
goto err;
}
#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
// Without immediate mode some architectures (e.g. Linux with
// TPACKET_V3) will buffer replies and incorrectly upwards of
// hundreds of milliseconds of delay.
if ((rc = pcap_set_immediate_mode(pcap, 1))) {
if (verbose) {
fprintf(stderr, "arping: pcap_set_immediate_mode() failed: %s\n", pcap_statustostr(rc));
}
}
#endif
#ifdef HAVE_PCAP_LIST_TSTAMP_TYPES
if (timestamp_type) {
int err;
int v = pcap_tstamp_type_name_to_val(timestamp_type);
if (v == PCAP_ERROR) {
fprintf(stderr, "arping: Unknown timestamp type \"%s\"\n", timestamp_type);
exit(1);
}
if ((err = pcap_set_tstamp_type(pcap, v))) {
fprintf(stderr,
"arping: Failed to set timestamp type \"%s\" (%d): %s\n",
timestamp_type, v, pcap_statustostr(err));
}
}
#endif
if ((rc = pcap_activate(pcap))) {
if (timestamp_type) {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "pcap_activate(tstype=\"%s\"): %s. Try without setting timestamp type.", timestamp_type, pcap_statustostr(rc));
} else {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "pcap_activate(): %s", pcap_statustostr(rc));
}
goto err;
}
#ifdef HAVE_PCAP_LIST_TSTAMP_TYPES
// List timestamp types after activating, since we don't want to list
// them if activating failed.
if (verbose > 1) {
int *ts;
int count;
count = pcap_list_tstamp_types(pcap, &ts);
if (count == PCAP_ERROR) {
fprintf(stderr, "arping: pcap_list_tstamp_types() failed\n");
} else {
int c;
const char* fmt = " %-18s %s\n";
fprintf(stderr, "Timestamp types:\n");
fprintf(stderr, fmt, "Name", "Description");
for (c = 0; c < count; c++) {
fprintf(stderr, fmt, pcap_tstamp_type_val_to_name(ts[c]),
pcap_tstamp_type_val_to_description(ts[c]));
}
pcap_free_tstamp_types(ts);
}
}
#endif
return pcap;
err:
if (pcap) {
pcap_close(pcap);
}
return NULL;
#else
return pcap_open_live(device, snaplen, promisc, to_ms, errbuf);
#endif
}
/**
* Some stupid OSs (Solaris) think it's a good idea to put network
* devices in /dev and then play musical chairs with them.
*
* Since libpcap doesn't seem to have a workaround for that, here's arpings
* workaround.
*
* E.g. if the network interface is called net0, pcap will fail because it
* fails to open /dev/net, because it's a directory.
*/
static pcap_t*
do_pcap_open_live(const char *device, int snaplen,
int promisc, int to_ms, char *errbuf)
{
pcap_t* ret;
char buf[PATH_MAX];
if ((ret = try_pcap_open_live(device, snaplen, promisc, to_ms, errbuf))) {
return ret;
}
snprintf(buf, sizeof(buf), "/dev/%s", device);
if ((ret = try_pcap_open_live(buf, snaplen, promisc, to_ms, errbuf))) {
return ret;
}
snprintf(buf, sizeof(buf), "/dev/net/%s", device);
if ((ret = try_pcap_open_live(buf, snaplen, promisc, to_ms, errbuf))) {
return ret;
}
/* Call original again to reset the error message. */
return try_pcap_open_live(device, snaplen, promisc, to_ms, errbuf);
}
/**
* Some Libnet error messages end with a newline. Strip that in place.
*/
void
strip_newline(char* s) {
if (!*s) {
return;
}
size_t n;
for (n = strlen(s); s[n - 1] == '\n'; --n) {
s[n - 1] = 0;
}
}
/**
* Init libnet with specified ifname. Destroy if already inited.
* If this function retries with different parameter it will preserve
* the original error message and print that.
* Call with recursive=0.
*/
void
do_libnet_init(const char *ifname, int recursive)
{
char ebuf[LIBNET_ERRBUF_SIZE];
ebuf[0] = 0;
if (verbose > 1) {
printf("arping: libnet_init(%s)\n", ifname ? ifname : "<null>");
}
if (libnet) {
/* Probably going to switch interface from temp to real. */
libnet_destroy(libnet);
libnet = 0;
}
/* Try libnet_init() even though we aren't root. We may have
* a capability or something. */
if (!(libnet = libnet_init(LIBNET_LINK,
(char*)ifname,
ebuf))) {
strip_newline(ebuf);
if (!ifname) {
/* Sometimes libnet guesses an interface that it then
* can't use. Work around that by attempting to
* use "lo". */
return do_libnet_init("lo", 1);
} else if (recursive) {
/* Continue original execution. */
return;
}
fprintf(stderr, "arping: libnet_init(LIBNET_LINK, %s): %s\n",
ifname ? ifname : "<null>", ebuf);
if (getuid() && geteuid()) {
fprintf(stderr,
"arping: you may need to run as root\n");
}
exit(1);
}
}
/**
*
*/
void
sigint(int i)
{
time_to_die = 1;
}
/**
* idiot-proof clock_gettime() wrapper
*/
static void
getclock(struct timespec *ts)
{
#if HAVE_CLOCK_MONOTONIC
if (-1 == clock_gettime(CLOCK_MONOTONIC, ts)) {
fprintf(stderr,
"arping: clock_gettime(): %s\n",
strerror(errno));
sigint(0);
}
#else
struct timeval tv;
if (-1 == gettimeofday(&tv, NULL)) {
fprintf(stderr, "arping: gettimeofday(): %s\n",
strerror(errno));
sigint(0);
}
ts->tv_sec = tv.tv_sec;
ts->tv_nsec = tv.tv_usec * 1000;
#endif
}
/**
*
*/
static char*
format_mac(unsigned char* mac, char* buf, size_t bufsize) {
snprintf(buf, bufsize, "%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
return buf;
}
/**
*
*/
static void
extended_usage()
{
printf("\nOptions:\n");
printf("\n"
" -0 Use this option to ping with source IP address 0.0.0.0. Use this\n"
" when you haven't configured your interface yet. Note that this\n"
" may get the MAC-ping unanswered. This is an alias for -S\n"
" 0.0.0.0.\n"
" -a Audiable ping.\n"
" -A Only count addresses matching requested address (This *WILL*\n"
" break most things you do. Only useful if you are arpinging many\n"
" hosts at once. See arping-scan-net.sh for an example).\n"
" -b Like -0 but source broadcast source address (255.255.255.255).\n"
" Note that this may get the arping unanswered since it's not nor-\n"
" mal behavior for a host.\n"
" -B Use instead of host if you want to address 255.255.255.255.\n"
" -c count\n"
" Only send count requests.\n"
" -C count\n"
" Only wait for this many replies, regardless of -c and -w.\n"
" -d Find duplicate replies. Exit with 1 if there are "
"answers from\n"
" two different MAC addresses.\n"
" -D Display answers as exclamation points and missing packets as dots.\n"
" -e Like -a but beep when there is no reply.\n"
" -F Don't try to be smart about the interface name. (even if this\n"
" switch is not given, -i overrides smartness)\n"
" -h Displays a help message and exits.\n"
" -i interface\n"
" Use the specified interface.\n"
" -m type"
#ifndef HAVE_PCAP_LIST_TSTAMP_TYPES
" (Disabled on this system. Option ignored)"
#endif
"\n Type of timestamp to use for incoming packets. Use -vv when\n"
" pinging to list available ones.\n"
" -q Does not display messages, except error messages.\n"
" -r Raw output: only the MAC/IP address is displayed for each reply.\n"
" -R Raw output: Like -r but shows \"the other one\", can be combined\n"
" with -r.\n"
" -s MAC Set source MAC address. You may need to use -p with this.\n"
" -S IP Like -b and -0 but with set source address. Note that this may\n"
" get the arping unanswered if the target does not have routing to\n"
" the IP. If you don't own the IP you are using, you may need to\n"
" turn on promiscious mode on the interface (with -p). With this\n"
" switch you can find out what IP-address a host has without tak-\n"
" ing an IP-address yourself.\n"
" -t MAC Set target MAC address to use when pinging IP address.\n"
" -T IP Use -T as target address when pinging MACs that won't respond to\n"
" a broadcast ping but perhaps to a directed broadcast.\n"
" Example:\n"
" To check the address of MAC-A, use knowledge of MAC-B and IP-B.\n"
" $ arping -S <IP-B> -s <MAC-B> -p <MAC-A>\n"
" -p Turn on promiscious mode on interface, use this if you don't\n"
" \"own\" the MAC address you are using.\n"
" -P Send ARP replies instead of requests. Useful with -U.\n"
" -u Show index=received/sent instead of just index=received when\n"
" pinging MACs.\n"
" -U Send unsolicited ARP.\n"
" -v Verbose output. Use twice for more messages.\n"
" -w Time to wait between pings, in microseconds.\n"
" -W Same as -w, but in floating point seconds.\n");
printf("Report bugs to: thomas@habets.se\n"
"Arping home page: <http://www.habets.pp.se/synscan/>\n"
"Development repo: http://github.com/ThomasHabets/arping\n");
}
/**
*
*/
static void
standard_usage()
{
printf("ARPing %s, by Thomas Habets <thomas@habets.se>\n",
version);
printf("usage: arping [ -0aAbdDeFpPqrRuUv ] [ -w <us> ] "
"[ -W <sec> ] "
"[ -S <host/ip> ]\n"
" "
"[ -T <host/ip ] "
"[ -s <MAC> ] [ -t <MAC> ] [ -c <count> ]\n"
" "
"[ -C <count> ] [ -i <interface> ] [ -m <type> ] "
"<host/ip/MAC | -B>\n");
}
/**
*
*/
static void
usage(int ret)
{
standard_usage();
if (WIN32) {
extended_usage();
} else {
printf("For complete usage info, use --help"
" or check the manpage.\n");
}
exit(ret);
}
/**
* It was unclear from msdn.microsoft.com if their scanf() supported
* [0-9a-fA-F], so I'll stay away from it.
*/
static int is_mac_addr(const char *p)
{
/* cisco-style */
if (3*5-1 == strlen(p)) {
unsigned int c;
for (c = 0; c < strlen(p); c++) {
if ((c % 5) == 4) {
if ('.' != p[c]) {
goto checkcolon;
}
} else {
if (!isxdigit(p[c])) {
goto checkcolon;
}
}
}
return 1;
}
/* windows-style */
if (6*3-1 == strlen(p)) {
unsigned int c;
for (c = 0; c < strlen(p); c++) {
if ((c % 3) == 2) {
if ('-' != p[c]) {
goto checkcolon;
}
} else {
if (!isxdigit(p[c])) {
goto checkcolon;
}
}
}
return 1;
}
checkcolon:
/* unix */
return strchr(p, ':') ? 1 : 0;
}
/**
* lots of parms since C arrays suck
*/
static int get_mac_addr(const char *in,
unsigned int *n0,
unsigned int *n1,
unsigned int *n2,
unsigned int *n3,
unsigned int *n4,
unsigned int *n5)
{
if (6 == sscanf(in, "%x:%x:%x:%x:%x:%x",n0,n1,n2,n3,n4,n5)) {
return 1;
} else if(6 == sscanf(in, "%2x%x.%2x%x.%2x%x",n0,n1,n2,n3,n4,n5)) {
return 1;
} else if(6 == sscanf(in, "%x-%x-%x-%x-%x-%x",n0,n1,n2,n3,n4,n5)) {
return 1;
}
return 0;
}
/**
*
*/
static void
update_stats(double sample)
{
if (stats_min_time < 0 || sample < stats_min_time) {
stats_min_time = sample;
}
if (sample > stats_max_time) {
stats_max_time = sample;
}
stats_total_time += sample;
stats_total_sq_time += sample * sample;
}
/**
*
*/
static double
timespec2dbl(const struct timespec *tv)
{
return tv->tv_sec + (double)tv->tv_nsec / 1000000000;
}
/**
* max size of buffer is intsize + 1 + intsize + 4 = 70 bytes or so
*
* Still, I'm using at least 128bytes below
*/
static char *ts2str(const struct timespec *tv, const struct timespec *tv2,
char *buf, size_t bufsize)
{
double f,f2;
int exp = 0;
f = timespec2dbl(tv);
f2 = timespec2dbl(tv2);
f = (f2 - f) * 1000000000;
while (f > 1000) {
exp += 3;
f /= 1000;
}
switch (exp) {
case 0:
snprintf(buf, bufsize, "%.3f nsec", f);
break;
case 3:
snprintf(buf, bufsize, "%.3f usec", f);
break;
case 6:
snprintf(buf, bufsize, "%.3f msec", f);
break;
case 9:
snprintf(buf, bufsize, "%.3f sec", f);
break;
case 12:
snprintf(buf, bufsize, "%.3f sec", f*1000);
break;
default:
/* huh, uh, huhuh */
snprintf(buf, bufsize, "%.3fe%d sec", f, exp-9);
}
return buf;
}
/** Send directed IPv4 ICMP echo request.
*
* \param id IP id
* \param seq Ping seq
*/
static void
pingmac_send(uint16_t id, uint16_t seq)
{
static libnet_ptag_t icmp = 0, ipv4 = 0,eth=0;
int c;
if (-1 == (icmp = libnet_build_icmpv4_echo(ICMP_ECHO, /* type */
0, /* code */
0, /* checksum */
id, /* id */
seq, /* seq */
NULL, /* payload */
0, /* payload len */
libnet,
icmp))) {
fprintf(stderr, "libnet_build_icmpv4_echo(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
if (-1==(ipv4 = libnet_build_ipv4(LIBNET_IPV4_H
+ LIBNET_ICMPV4_ECHO_H + 0,
0, /* ToS */
id, /* id */
0, /* frag */
64, /* ttl */
IPPROTO_ICMP,
0, /* checksum */
srcip,
dstip,
NULL, /* payload */
0,
libnet,
ipv4))) {
fprintf(stderr, "libnet_build_ipv4(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
if (-1 == (eth = libnet_build_ethernet(dstmac,
srcmac,
ETHERTYPE_IP,
NULL,
0,
libnet,
eth))) {
fprintf(stderr, "libnet_build_ethernet(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
if (verbose > 1) {
getclock(&lastpacketsent);
printf("arping: sending packet at time %ld.%09ld\n",
(long)lastpacketsent.tv_sec,
(long)lastpacketsent.tv_nsec);
}
if (-1 == (c = libnet_write(libnet))) {
fprintf(stderr, "arping: libnet_write(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
getclock(&lastpacketsent);
numsent++;
}
/** Send ARP who-has.
*
*/
static void
pingip_send()
{
static libnet_ptag_t arp=0,eth=0;
if (-1 == (arp = libnet_build_arp(ARPHRD_ETHER,
ETHERTYPE_IP,
ETH_ALEN,
IP_ALEN,
send_reply ? ARPOP_REPLY : ARPOP_REQUEST,
srcmac,
(uint8_t*)&srcip,
unsolicited ? (uint8_t*)ethxmas : (uint8_t*)ethnull,
(uint8_t*)&dstip,
NULL,
0,
libnet,
arp))) {
fprintf(stderr, "arping: libnet_build_arp(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
if (-1 == (eth = libnet_build_ethernet(dstmac,
srcmac,
ETHERTYPE_ARP,
NULL,
0,
libnet,
eth))) {
fprintf(stderr, "arping: libnet_build_ethernet(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
if (verbose > 1) {
getclock(&lastpacketsent);
printf("arping: sending packet at time %ld.%09ld\n",
(long)lastpacketsent.tv_sec,
(long)lastpacketsent.tv_nsec);
}
if (-1 == libnet_write(libnet)) {
fprintf(stderr, "arping: libnet_write(): %s\n",
libnet_geterror(libnet));
sigint(0);
}
getclock(&lastpacketsent);
numsent++;
}
/** handle incoming packet when pinging an IP address.
*
* \param h packet metadata
* \param packet packet data
*/
static void
pingip_recv(const char *unused, struct pcap_pkthdr *h, uint8_t *packet)
{
struct libnet_802_3_hdr *heth;
struct libnet_arp_hdr *harp;
struct timespec arrival;
int c;
if (verbose > 2) {
printf("arping: received response for IP ping\n");
}
getclock(&arrival);
heth = (void*)packet;
harp = (void*)((char*)heth + LIBNET_ETH_H);
// ARP reply.
if (htons(harp->ar_op) != ARPOP_REPLY) {
return;
}
if (verbose > 3) {
printf("arping: ... packet is ARP reply\n");
}
// From IPv4 address reply.
if (htons(harp->ar_pro) != ETHERTYPE_IP) {
return;
}
if (verbose > 3) {
printf("arping: ... from IPv4 address\n");
}
// To Ethernet address.
if (htons(harp->ar_hrd) != ARPHRD_ETHER) {
return;
}
if (verbose > 3) {
printf("arping: ... to Ethernet address\n");
}
// Must be sent from target address.
// Should very likely only be used if using -T.
if (addr_must_be_same) {
if (memcmp((u_char*)harp + sizeof(struct libnet_arp_hdr),
dstmac, ETH_ALEN)) {
return;
}
}
if (verbose > 3) {
printf("arping: ... sent by acceptable host\n");
}
// Actually the IPv4 address we asked for.
uint32_t ip;
memcpy(&ip, (char*)harp + harp->ar_hln + LIBNET_ARP_H, 4);
if (dstip != ip) {
return;
}
if (verbose > 3) {
printf("arping: ... for the right IPv4 address!\n");
}
update_stats(timespec2dbl(&arrival) - timespec2dbl(&lastpacketsent));
char buf[128];
if (beep) {
printf("\a");
}
switch(display) {
case DOT:
putchar('!');
break;
case NORMAL:
printf("%d bytes from %s (%s): index=%d",
h->len, format_mac(heth->_802_3_shost,
buf, sizeof(buf)),
libnet_addr2name4(ip, 0), numrecvd);
if (alsototal) {
printf("/%u", numsent-1);
}
printf(" time=%s", ts2str(&lastpacketsent, &arrival, buf,
sizeof(buf)));
break;
case QUIET:
break;
case RAWRAW:
printf("%s %s", format_mac(heth->_802_3_shost,
buf, sizeof(buf)),
libnet_addr2name4(ip, 0));
break;
case RRAW:
printf("%s", libnet_addr2name4(ip, 0));
break;
case RAW:
printf("%s", format_mac(heth->_802_3_shost,
buf, sizeof(buf)));
break;
default:
fprintf(stderr, "arping: can't happen!\n");
}
fflush(stdout);
switch (display) {
case QUIET:
case DOT:
break;
default:
printf("\n");
}
if (numrecvd) {
if (memcmp(lastreplymac,
heth->_802_3_shost, ETH_ALEN)) {
dupfound = 1;
}
}
memcpy(lastreplymac, heth->_802_3_shost, ETH_ALEN);
numrecvd++;
if (numrecvd >= max_replies) {
sigint(0);
}
}
/** handle incoming packet when pinging an MAC address.
*
* \param h packet metadata
* \param packet packet data
*/
static void
pingmac_recv(const char *unused, struct pcap_pkthdr *h, uint8_t *packet)
{
struct libnet_802_3_hdr *heth;
struct libnet_ipv4_hdr *hip;
struct libnet_icmpv4_hdr *hicmp;
struct timespec arrival;
int c;
if(verbose>2) {
printf("arping: received response for mac ping\n");
}
getclock(&arrival);
heth = (void*)packet;
hip = (void*)((char*)heth + LIBNET_ETH_H);
hicmp = (void*)((char*)hip + LIBNET_IPV4_H);
// Dest MAC must be me.
if (memcmp(heth->_802_3_dhost, srcmac, ETH_ALEN)) {
return;
}
// Source MAC must match, if set.
if (memcmp(dstmac, ethxmas, ETH_ALEN)) {
if (memcmp(heth->_802_3_shost, dstmac, ETH_ALEN)) {
return;
}
}
// IPv4 Address must be me (maybe).
if (addr_must_be_same) {
uint32_t tmp;
memcpy(&tmp, &hip->ip_src, 4);
if (dstip != tmp) {
return;
}
}
// Must be ICMP echo reply.
if (htons(hicmp->icmp_type) != ICMP_ECHOREPLY) {
return;
}
update_stats(timespec2dbl(&arrival) - timespec2dbl(&lastpacketsent));
if (beep) {
printf("\a");
}
char buf[128];
char buf2[128];
switch(display) {
case QUIET:
break;
case DOT:
putchar('!');
break;
case NORMAL:
printf("%d bytes from %s (%s): icmp_seq=%d time=%s", h->len,
libnet_addr2name4(*(int*)&hip->ip_src, 0),
format_mac(heth->_802_3_shost, buf, sizeof(buf)),
htons(hicmp->icmp_seq),
ts2str(&lastpacketsent, &arrival, buf2, sizeof(buf2)));
break;
case RAW:
printf("%s", libnet_addr2name4(hip->ip_src.s_addr, 0));
break;
case RRAW:
printf("%s", format_mac(heth->_802_3_shost, buf, sizeof(buf)));
break;
case RAWRAW:
printf("%s %s",
format_mac(heth->_802_3_shost, buf, sizeof(buf)),
libnet_addr2name4(hip->ip_src.s_addr, 0));
break;
default:
fprintf(stderr, "arping: can't-happen-bug\n");
sigint(0);
}
fflush(stdout);
switch (display) {
case QUIET:
case DOT:
break;
default:
printf("\n");
}
numrecvd++;
if (numrecvd >= max_replies) {
sigint(0);
}
}
/**
* while negative nanoseconds, take from whole seconds.
* help function for measuring deltas.
*/
static void
fixup_timespec(struct timespec *tv)
{
while (tv->tv_nsec < 0) {
tv->tv_sec--;
tv->tv_nsec += 1000000000;
}
}
/**
* try to receive a packet for 'packetwait' microseconds
*/
static void
ping_recv(pcap_t *pcap, uint32_t packetwait, pcap_handler func)
{
struct timespec ts;
struct timespec endtime;
char done = 0;
int fd;
int old_received;
if (verbose > 3) {
printf("arping: receiving packets...\n");
}
getclock(&ts);
endtime.tv_sec = ts.tv_sec + (packetwait / 1000000);
endtime.tv_nsec = ts.tv_nsec + 1000 * (packetwait % 1000000);
fixup_timespec(&endtime);
fd = pcap_get_selectable_fd(pcap);
old_received = numrecvd;
for (;!done;) {
int trydispatch = 0;
getclock(&ts);
ts.tv_sec = endtime.tv_sec - ts.tv_sec;
ts.tv_nsec = endtime.tv_nsec - ts.tv_nsec;
fixup_timespec(&ts);
if (verbose > 2) {
printf("arping: listen for replies for %ld.%09ld sec\n",
(long)ts.tv_sec, (long)ts.tv_nsec);
}
/* if time has passed, do one last check and then we're done.
* this also triggers if not using monotonic clock and time
* is set forwards */
if (ts.tv_sec < 0) {
ts.tv_sec = 0;
ts.tv_nsec = 1;
done = 1;
}
/* if wait-for-packet time is longer than full period,
* we're obviously not using a monotonic clock and the system
* time has been changed.
* we don't know how far we're into the waiting, so just end
* it here */
if ((ts.tv_sec > packetwait / 1000000)
|| ((ts.tv_sec == packetwait / 1000000)
&& (ts.tv_nsec/1000 > packetwait % 1000000))) {
ts.tv_sec = 0;
ts.tv_nsec = 1;
done = 1;
}
/* check for sigint */
if (time_to_die) {
return;
}
/* try to wait for data */
{
fd_set fds;
int r;
struct timeval tv;
tv.tv_sec = ts.tv_sec;
tv.tv_usec = ts.tv_nsec / 1000;
FD_ZERO(&fds);
FD_SET(fd, &fds);
r = select(fd + 1, &fds, NULL, NULL, &tv);
switch (r) {
case 0: /* timeout */
if (numrecvd == old_received) {
if (reverse_beep) {
printf("\a");
}
switch (display) {
case NORMAL:
printf("Timeout\n");
break;
case DOT:
printf(".");
break;
}
fflush(stdout);
}
done = 1;
break;
case -1: /* error */
if (errno != EINTR) {
done = 1;
sigint(0);
fprintf(stderr,
"arping: select() failed: %s\n",
strerror(errno));
}
break;
default: /* data returned */
trydispatch = 1;
break;
}
}
if (trydispatch) {
int ret;
if (0 > (ret = pcap_dispatch(pcap, -1,
func,
NULL))) {
/* rest, so we don't take 100% CPU... mostly
hmm... does usleep() exist everywhere? */
usleep(1);
/* weird is normal on bsd :) */
if (verbose > 3) {
fprintf(stderr,
"arping: select says ok, but "
"pcap_dispatch=%d!\n",
ret);
}
}
}
}
}
/**
*
*/
int main(int argc, char **argv)
{
char ebuf[LIBNET_ERRBUF_SIZE + PCAP_ERRBUF_SIZE];
char *cp;
int promisc = 0;
int srcip_given = 0;
int srcmac_given = 0;
int dstip_given = 0;
const char *ifname = NULL;
char *parm;
int c;
unsigned int maxcount = -1;
int dont_use_arping_lookupdev=0;
struct bpf_program bp;
pcap_t *pcap;
enum { NONE, PINGMAC, PINGIP } mode = NONE;
unsigned int packetwait = 1000000;
ebuf[0] = 0;
for (c = 1; c < argc; c++) {
if (!strcmp(argv[c], "--help")) {
standard_usage();
extended_usage();
exit(0);
}
}
srcip = 0;
dstip = 0xffffffff;
memcpy(dstmac, ethxmas, ETH_ALEN);
while (EOF != (c = getopt(argc, argv,
"0aAbBC:c:dDeFhi:I:m:pPqrRs:S:t:T:uUvw:W:"))) {
switch(c) {
case '0':
srcip = 0;
srcip_given = 1;
break;
case 'a':
beep = 1;
break;
case 'A':
addr_must_be_same = 1;
break;
case 'b':
srcip = 0xffffffff;
srcip_given = 1;
break;
case 'B':
dstip = 0xffffffff;
dstip_given = 1;
break;
case 'c':
maxcount = atoi(optarg);
break;
case 'C':
max_replies = atoi(optarg);
break;
case 'd':
finddup = 1;
break;
case 'D':
display = DOT;
break;
case 'e':
reverse_beep = 1;
break;
case 'F':
dont_use_arping_lookupdev=1;
break;
case 'h':
usage(0);
case 'i':
if (strchr(optarg, ':')) {
fprintf(stderr, "arping: If you're trying to "
"feed me an interface alias then you "
"don't really\nknow what this programs"
" does, do you?\nUse -I if you really"
" mean it (undocumented on "
"purpose)\n");
exit(1);
}
case 'I': /* FALL THROUGH */
ifname = optarg;
break;
case 'm':
timestamp_type = optarg;
break;
case 'p':
promisc = 1;
break;
case 'P':
send_reply = 1;
break;
case 'q':
display = QUIET;
break;
case 'r':
display = (display==RRAW)?RAWRAW:RAW;
break;
case 'R':
display = (display==RAW)?RAWRAW:RRAW;
break;
case 's': { /* spoof source MAC */
unsigned int n[6];
if (!get_mac_addr(optarg,
&n[0],&n[1],&n[2],
&n[3],&n[4],&n[5])){
fprintf(stderr, "arping: Weird MAC addr %s\n",
optarg);
exit(1);
}
for (c = 0; c < 6; c++) {
srcmac[c] = n[c] & 0xff;
}
srcmac_given = 1;
break;
}
case 'S': /* set source IP, may be null for don't-know */
do_libnet_init(ifname, 0);
if (-1 == (srcip = libnet_name2addr4(libnet,
optarg,
LIBNET_RESOLVE))){
fprintf(stderr, "arping: Can't resolve %s, or "
"%s is broadcast. If it is, use -b"
" instead of -S\n", optarg,optarg);
exit(1);
}
srcip_given = 1;
break;
case 't': { /* set taget mac */
unsigned int n[6];
if (mode == PINGMAC) {
fprintf(stderr, "arping: -t can only be used "
"in IP ping mode\n");
exit(1);
}
if (!get_mac_addr(optarg,
&n[0],&n[1],&n[2],
&n[3],&n[4],&n[5])){
fprintf(stderr, "Illegal MAC addr %s\n",
optarg);
exit(1);
}
for (c = 0; c < 6; c++) {
dstmac[c] = n[c] & 0xff;
}
mode = PINGIP;
break;
}
case 'T': /* set destination IP */
if (mode == PINGIP) {
fprintf(stderr, "arping: -T can only be used "
"in MAC ping mode\n");
exit(1);
}
do_libnet_init(ifname, 0);
if (-1 == (dstip = libnet_name2addr4(libnet,
optarg,
LIBNET_RESOLVE))){
fprintf(stderr,"arping: Can't resolve %s, or "
"%s is broadcast. If it is, use -B "
"instead of -T\n",optarg,optarg);
exit(1);
}
mode = PINGMAC;
break;
case 'u':
alsototal = 1;
break;
case 'U':
if (mode == PINGMAC) {
fprintf(stderr, "arping: -U can only be used "
"in IP ping mode\n");
exit(1);
}
unsolicited = 1;
break;
case 'v':
verbose++;
break;
case 'w':
packetwait = (unsigned)atoi(optarg);
break;
case 'W':
packetwait = (unsigned)(1000000.0 * atof(optarg));
break;
default:
usage(1);
}
}
if (verbose > 1) {
#if HAVE_CLOCK_MONOTONIC
struct timespec ts;
clock_getres(CLOCK_MONOTONIC, &ts);
printf("arping: clock_getres() = %ld %ld\n",
(long)ts.tv_sec, (long)ts.tv_nsec);
#else
printf("arping: Using gettimeofday() for time measurements\n");
#endif
}
if (display == DOT) {
setvbuf(stdout, NULL, _IONBF, 0);
}
if (finddup && maxcount == -1) {
maxcount = 3;
}
parm = (optind < argc) ? argv[optind] : NULL;
/* default to own IP address when doing -d */
if (finddup && !parm) {
dstip_given = 1;
do_libnet_init(ifname, 0);
dstip = libnet_get_ipaddr4(libnet);
if (verbose) {
printf("defaulting to checking dup for %s\n",
libnet_addr2name4(dstip, 0));
}
}
/*
* Handle dstip_given instead of ip address after parms (-B really)
*/
if (mode == NONE) {
if (optind + 1 == argc) {
mode = is_mac_addr(parm)?PINGMAC:PINGIP;
} else if (dstip_given) {
mode = PINGIP;
do_libnet_init(ifname, 0);
parm = strdup(libnet_addr2name4(dstip,0));
if (!parm) {
fprintf(stderr, "arping: out of mem\n");
exit(1);
}
}
}
if (!parm) {
usage(1);
}
/*
*
*/
if (mode == NONE) {
usage(1);
}
/*
* libnet init (may be done already for resolving)
*/
do_libnet_init(ifname, 0);
/*
* Make sure dstip and parm like eachother
*/
if (mode == PINGIP && (!dstip_given)) {
if (is_mac_addr(parm)) {
fprintf(stderr, "arping: Options given only apply to "
"IP ping, but MAC address given as argument"
"\n");
exit(1);
}
if (-1 == (dstip = libnet_name2addr4(libnet,
parm,
LIBNET_RESOLVE))) {
fprintf(stderr, "arping: Can't resolve %s\n", parm);
exit(1);
}
parm = strdup(libnet_addr2name4(dstip,0));
}
/*
* parse parm into dstmac
*/
if (mode == PINGMAC) {
unsigned int n[6];
if (optind + 1 != argc) {
usage(1);
}
if (!is_mac_addr(parm)) {
fprintf(stderr, "arping: Options given only apply to "
"MAC ping, but no MAC address given as "
"argument\n");
exit(1);
}
if (!get_mac_addr(argv[optind],
&n[0],&n[1],&n[2],
&n[3],&n[4],&n[5])) {
fprintf(stderr, "arping: Illegal mac addr %s\n",
argv[optind]);
return 1;
}
for (c = 0; c < 6; c++) {
dstmac[c] = n[c] & 0xff;
}
}
target = parm;
/*
* Argument processing done, parameters considered sane below
*/
/*
* Get some good iface.
*/
if (!ifname) {
if (!dont_use_arping_lookupdev) {
ifname = arping_lookupdev(srcip, dstip, ebuf);
strip_newline(ebuf);
if (!ifname) {
fprintf(stderr, "arping: lookup dev: %s\n",
ebuf);
}
}
if (!ifname) {
ifname = arping_lookupdev_default(srcip, dstip, ebuf);
strip_newline(ebuf);
if (ifname && !dont_use_arping_lookupdev) {
fprintf(stderr,
"arping: Unable to automatically find "
"interface to use. Is it on the local "
"LAN?\n"
"arping: Use -i to manually "
"specify interface. "
"Guessing interface %s.\n", ifname);
}
}
if (!ifname) {
fprintf(stderr, "arping: Gave up looking for interface"
" to use: %s\n", ebuf);
exit(1);
}
/* FIXME: check for other probably-not interfaces */
if (!strcmp(ifname, "ipsec")
|| !strcmp(ifname,"lo")) {
fprintf(stderr, "arping: Um.. %s looks like the wrong "
"interface to use. Is it? "
"(-i switch)\n", ifname);
fprintf(stderr, "arping: using it anyway this time\n");
}
}
/*
* Init libnet again, because we now know the interface name.
* We should know it by know at least
*/
do_libnet_init(ifname, 0);
/*
* pcap init
*/
if (!(pcap = do_pcap_open_live(ifname, 100, promisc, 10, ebuf))) {
strip_newline(ebuf);
fprintf(stderr, "arping: pcap_open_live(): %s\n", ebuf);
exit(1);
}
drop_privileges();
if (pcap_setnonblock(pcap, 1, ebuf)) {
strip_newline(ebuf);
fprintf(stderr, "arping: pcap_set_nonblock(): %s\n", ebuf);
exit(1);
}
if (verbose > 1) {
printf("arping: pcap_get_selectable_fd(): %d\n",
pcap_get_selectable_fd(pcap));
}
#ifdef BIOCIMMEDIATE
{
// This may be redundant if pcap_set_immediate_mode() is present.
uint32_t on = 1;
if (0 < (ioctl(pcap_fileno(pcap), BIOCIMMEDIATE,
&on))) {
fprintf(stderr, "arping: ioctl(fd,BIOCIMMEDIATE, 1) "
"failed, continuing anyway, YMMV: %s\n",
strerror(errno));
}
}
#endif
if (mode == PINGIP) {
/* FIXME: better filter with addresses? */
if (-1 == pcap_compile(pcap, &bp, "arp", 0,-1)) {
fprintf(stderr, "arping: pcap_compile(): error\n");
exit(1);
}
} else { /* ping mac */
/* FIXME: better filter with addresses? */
if (-1 == pcap_compile(pcap, &bp, "icmp", 0,-1)) {
fprintf(stderr, "arping: pcap_compile(): error\n");
exit(1);
}
}
if (-1 == pcap_setfilter(pcap, &bp)) {
fprintf(stderr, "arping: pcap_setfilter(): error\n");
exit(1);
}
/*
* final init
*/
if (!srcmac_given) {
if (!(cp = (char*)libnet_get_hwaddr(libnet))) {
fprintf(stderr, "arping: libnet_get_hwaddr(): %s\n",
libnet_geterror(libnet));
exit(1);
}
memcpy(srcmac, cp, ETH_ALEN);
}
if (!srcip_given) {
if (-1 == (srcip = libnet_get_ipaddr4(libnet))) {
fprintf(stderr,
"arping: Unable to get the IPv4 address of "
"interface %s:\narping: %s"
"arping: "
"Use -S to specify address manually.\n",
ifname, libnet_geterror(libnet));
exit(1);
}
}
do_signal_init();
if (verbose) {
char buf[128];
printf("This box: Interface: %s IP: %s MAC address: %s\n",
ifname,
libnet_addr2name4(libnet_get_ipaddr4(libnet), 0),
format_mac(srcmac, buf, sizeof(buf)));
}
if (display == NORMAL) {
printf("ARPING %s\n", parm);
}
/*
* let's roll
*/
if (mode == PINGIP) {
unsigned int c;
unsigned int r;
for (c = 0; c < maxcount && !time_to_die; c++) {
pingip_send();
r = numrecvd;
ping_recv(pcap,packetwait,
(pcap_handler)pingip_recv);
}
} else { /* PINGMAC */
unsigned int c;
unsigned int r;
for (c = 0; c < maxcount && !time_to_die; c++) {
pingmac_send(rand(), c);
r = numrecvd;
ping_recv(pcap,packetwait,
(pcap_handler)pingmac_recv);
}
}
if (display == DOT) {
const float succ = 100.0 - 100.0 * (float)(numrecvd)/(float)numsent;
printf("\t%3.0f%% packet loss (%d extra)\n",
(succ < 0.0) ? 0.0 : succ,
(succ < 0.0) ? (numrecvd - numsent) : 0);
} else if (display == NORMAL) {
const float succ = 100.0 - 100.0 * (float)(numrecvd)/(float)numsent;
printf("\n--- %s statistics ---\n"
"%d packets transmitted, "
"%d packets received, "
"%3.0f%% "
"unanswered (%d extra)\n",
target,numsent,numrecvd,
(succ < 0.0) ? 0.0 : succ,
(succ < 0.0) ? (numrecvd - numsent): 0);
if (numrecvd) {
double avg = stats_total_time / numrecvd;
printf("rtt min/avg/max/std-dev = "
"%.3f/%.3f/%.3f/%.3f ms",
1000*stats_min_time,
1000*avg,
1000*stats_max_time,
1000*sqrt(stats_total_sq_time/numrecvd
-avg*avg));
}
printf("\n");
}
if (finddup) {
return dupfound;
} else {
return !numrecvd;
}
}
/* ---- Emacs Variables ----
* Local Variables:
* c-basic-offset: 8
* indent-tabs-mode: nil
* End:
*/
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