/*
* arping.c
*
* 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.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
* YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
*/
#include <stdlib.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <linux/sockios.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/signal.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <net/if_arp.h>
#include <sys/uio.h>
#ifdef CAPABILITIES
#include <sys/prctl.h>
#include <sys/capability.h>
#endif
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef USE_SYSFS
#include <sysfs/libsysfs.h>
struct sysfs_devattr_values;
#endif
#ifndef WITHOUT_IFADDRS
#include <ifaddrs.h>
#endif
#ifdef USE_IDN
#include <idna.h>
#include <locale.h>
#endif
#include "SNAPSHOT.h"
static void usage(void) __attribute__((noreturn));
#ifdef DEFAULT_DEVICE
# define DEFAULT_DEVICE_STR DEFAULT_DEVICE
#else
# define DEFAULT_DEVICE NULL
#endif
struct device {
char *name;
int ifindex;
#ifndef WITHOUT_IFADDRS
struct ifaddrs *ifa;
#endif
#ifdef USE_SYSFS
struct sysfs_devattr_values *sysfs;
#endif
};
int quit_on_reply=0;
struct device device = {
.name = DEFAULT_DEVICE,
};
char *source;
struct in_addr src, dst;
char *target;
int dad, unsolicited, advert;
int quiet;
int count=-1;
int timeout;
int unicasting;
int s;
int broadcast_only;
struct sockaddr_storage me;
struct sockaddr_storage he;
struct timeval start, last;
int sent, brd_sent;
int received, brd_recv, req_recv;
#ifndef CAPABILITIES
static uid_t euid;
#endif
#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
((tv1).tv_usec-(tv2).tv_usec)/1000 )
#define OFFSET_OF(name,ele) ((size_t)(((name *)0)->ele))
static inline socklen_t sll_len(size_t halen)
{
socklen_t len = OFFSET_OF(struct sockaddr_ll, sll_addr) + halen;
if (len < sizeof(struct sockaddr_ll))
len = sizeof(struct sockaddr_ll);
return len;
}
#define SLL_LEN(hln) sll_len(hln)
void usage(void)
{
fprintf(stderr,
"Usage: arping [-fqbDUAV] [-c count] [-w timeout] [-I device] [-s source] destination\n"
" -f : quit on first reply\n"
" -q : be quiet\n"
" -b : keep broadcasting, don't go unicast\n"
" -D : duplicate address detection mode\n"
" -U : Unsolicited ARP mode, update your neighbours\n"
" -A : ARP answer mode, update your neighbours\n"
" -V : print version and exit\n"
" -c count : how many packets to send\n"
" -w timeout : how long to wait for a reply\n"
" -I device : which ethernet device to use"
#ifdef DEFAULT_DEVICE_STR
" (" DEFAULT_DEVICE_STR ")"
#endif
"\n"
" -s source : source ip address\n"
" destination : ask for what ip address\n"
);
exit(2);
}
void set_signal(int signo, void (*handler)(void))
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = (void (*)(int))handler;
sa.sa_flags = SA_RESTART;
sigaction(signo, &sa, NULL);
}
#ifdef CAPABILITIES
static const cap_value_t caps[] = { CAP_NET_RAW, };
static cap_flag_value_t cap_raw = CAP_CLEAR;
#endif
void limit_capabilities(void)
{
#ifdef CAPABILITIES
cap_t cap_p;
cap_p = cap_get_proc();
if (!cap_p) {
perror("arping: cap_get_proc");
exit(-1);
}
cap_get_flag(cap_p, CAP_NET_RAW, CAP_PERMITTED, &cap_raw);
if (cap_raw != CAP_CLEAR) {
if (cap_clear(cap_p) < 0) {
perror("arping: cap_clear");
exit(-1);
}
cap_set_flag(cap_p, CAP_PERMITTED, 1, caps, CAP_SET);
if (cap_set_proc(cap_p) < 0) {
perror("arping: cap_set_proc");
if (errno != EPERM)
exit(-1);
}
}
if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
perror("arping: prctl");
exit(-1);
}
if (setuid(getuid()) < 0) {
perror("arping: setuid");
exit(-1);
}
if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
perror("arping: prctl");
exit(-1);
}
cap_free(cap_p);
#else
euid = geteuid();
#endif
}
int modify_capability_raw(int on)
{
#ifdef CAPABILITIES
cap_t cap_p;
if (cap_raw != CAP_SET)
return on ? -1 : 0;
cap_p = cap_get_proc();
if (!cap_p) {
perror("arping: cap_get_proc");
return -1;
}
cap_set_flag(cap_p, CAP_EFFECTIVE, 1, caps, on ? CAP_SET : CAP_CLEAR);
if (cap_set_proc(cap_p) < 0) {
perror("arping: cap_set_proc");
return -1;
}
cap_free(cap_p);
#else
if (setuid(on ? euid : getuid())) {
perror("arping: setuid");
return -1;
}
#endif
return 0;
}
static inline int enable_capability_raw(void)
{
return modify_capability_raw(1);
}
static inline int disable_capability_raw(void)
{
return modify_capability_raw(0);
}
void drop_capabilities(void)
{
#ifdef CAPABILITIES
cap_t cap_p = cap_init();
if (!cap_p) {
perror("arping: cap_init");
exit(-1);
}
if (cap_set_proc(cap_p) < 0) {
perror("arping: cap_set_proc");
exit(-1);
}
cap_free(cap_p);
#else
if (setuid(getuid()) < 0) {
perror("arping: setuid");
exit(-1);
}
#endif
}
int send_pack(int s, struct in_addr src, struct in_addr dst,
struct sockaddr_ll *ME, struct sockaddr_ll *HE)
{
int err;
struct timeval now;
unsigned char buf[256];
struct arphdr *ah = (struct arphdr*)buf;
unsigned char *p = (unsigned char *)(ah+1);
ah->ar_hrd = htons(ME->sll_hatype);
if (ah->ar_hrd == htons(ARPHRD_FDDI))
ah->ar_hrd = htons(ARPHRD_ETHER);
ah->ar_pro = htons(ETH_P_IP);
ah->ar_hln = ME->sll_halen;
ah->ar_pln = 4;
ah->ar_op = advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
memcpy(p, &ME->sll_addr, ah->ar_hln);
p+=ME->sll_halen;
memcpy(p, &src, 4);
p+=4;
if (advert)
memcpy(p, &ME->sll_addr, ah->ar_hln);
else
memcpy(p, &HE->sll_addr, ah->ar_hln);
p+=ah->ar_hln;
memcpy(p, &dst, 4);
p+=4;
gettimeofday(&now, NULL);
err = sendto(s, buf, p-buf, 0, (struct sockaddr*)HE, SLL_LEN(ah->ar_hln));
if (err == p-buf) {
last = now;
sent++;
if (!unicasting)
brd_sent++;
}
return err;
}
void finish(void)
{
if (!quiet) {
printf("Sent %d probes (%d broadcast(s))\n", sent, brd_sent);
printf("Received %d response(s)", received);
if (brd_recv || req_recv) {
printf(" (");
if (req_recv)
printf("%d request(s)", req_recv);
if (brd_recv)
printf("%s%d broadcast(s)",
req_recv ? ", " : "",
brd_recv);
printf(")");
}
printf("\n");
fflush(stdout);
}
if (dad)
exit(!!received);
if (unsolicited)
exit(0);
exit(!received);
}
void catcher(void)
{
struct timeval tv, tv_s, tv_o;
gettimeofday(&tv, NULL);
if (start.tv_sec==0)
start = tv;
timersub(&tv, &start, &tv_s);
tv_o.tv_sec = timeout;
tv_o.tv_usec = 500 * 1000;
if (count-- == 0 || (timeout && timercmp(&tv_s, &tv_o, >)))
finish();
timersub(&tv, &last, &tv_s);
tv_o.tv_sec = 0;
if (last.tv_sec==0 || timercmp(&tv_s, &tv_o, >)) {
send_pack(s, src, dst,
(struct sockaddr_ll *)&me, (struct sockaddr_ll *)&he);
if (count == 0 && unsolicited)
finish();
}
alarm(1);
}
void print_hex(unsigned char *p, int len)
{
int i;
for (i=0; i<len; i++) {
printf("%02X", p[i]);
if (i != len-1)
printf(":");
}
}
int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
{
struct timeval tv;
struct arphdr *ah = (struct arphdr*)buf;
unsigned char *p = (unsigned char *)(ah+1);
struct in_addr src_ip, dst_ip;
gettimeofday(&tv, NULL);
/* Filter out wild packets */
if (FROM->sll_pkttype != PACKET_HOST &&
FROM->sll_pkttype != PACKET_BROADCAST &&
FROM->sll_pkttype != PACKET_MULTICAST)
return 0;
/* Only these types are recognised */
if (ah->ar_op != htons(ARPOP_REQUEST) &&
ah->ar_op != htons(ARPOP_REPLY))
return 0;
/* ARPHRD check and this darned FDDI hack here :-( */
if (ah->ar_hrd != htons(FROM->sll_hatype) &&
(FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
return 0;
/* Protocol must be IP. */
if (ah->ar_pro != htons(ETH_P_IP))
return 0;
if (ah->ar_pln != 4)
return 0;
if (ah->ar_hln != ((struct sockaddr_ll *)&me)->sll_halen)
return 0;
if (len < sizeof(*ah) + 2*(4 + ah->ar_hln))
return 0;
memcpy(&src_ip, p+ah->ar_hln, 4);
memcpy(&dst_ip, p+ah->ar_hln+4+ah->ar_hln, 4);
if (!dad) {
if (src_ip.s_addr != dst.s_addr)
return 0;
if (src.s_addr != dst_ip.s_addr)
return 0;
if (memcmp(p+ah->ar_hln+4, ((struct sockaddr_ll *)&me)->sll_addr, ah->ar_hln))
return 0;
} else {
/* DAD packet was:
src_ip = 0 (or some src)
src_hw = ME
dst_ip = tested address
dst_hw = <unspec>
We fail, if receive request/reply with:
src_ip = tested_address
src_hw != ME
if src_ip in request was not zero, check
also that it matches to dst_ip, otherwise
dst_ip/dst_hw do not matter.
*/
if (src_ip.s_addr != dst.s_addr)
return 0;
if (memcmp(p, ((struct sockaddr_ll *)&me)->sll_addr, ((struct sockaddr_ll *)&me)->sll_halen) == 0)
return 0;
if (src.s_addr && src.s_addr != dst_ip.s_addr)
return 0;
}
if (!quiet) {
int s_printed = 0;
printf("%s ", FROM->sll_pkttype==PACKET_HOST ? "Unicast" : "Broadcast");
printf("%s from ", ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request");
printf("%s [", inet_ntoa(src_ip));
print_hex(p, ah->ar_hln);
printf("] ");
if (dst_ip.s_addr != src.s_addr) {
printf("for %s ", inet_ntoa(dst_ip));
s_printed = 1;
}
if (memcmp(p+ah->ar_hln+4, ((struct sockaddr_ll *)&me)->sll_addr, ah->ar_hln)) {
if (!s_printed)
printf("for ");
printf("[");
print_hex(p+ah->ar_hln+4, ah->ar_hln);
printf("]");
}
if (last.tv_sec) {
long usecs = (tv.tv_sec-last.tv_sec) * 1000000 +
tv.tv_usec-last.tv_usec;
long msecs = (usecs+500)/1000;
usecs -= msecs*1000 - 500;
printf(" %ld.%03ldms\n", msecs, usecs);
} else {
printf(" UNSOLICITED?\n");
}
fflush(stdout);
}
received++;
if (FROM->sll_pkttype != PACKET_HOST)
brd_recv++;
if (ah->ar_op == htons(ARPOP_REQUEST))
req_recv++;
if (quit_on_reply)
finish();
if(!broadcast_only) {
memcpy(((struct sockaddr_ll *)&he)->sll_addr, p, ((struct sockaddr_ll *)&me)->sll_halen);
unicasting=1;
}
return 1;
}
#ifdef USE_SYSFS
union sysfs_devattr_value {
unsigned long ulong;
void *ptr;
};
enum {
SYSFS_DEVATTR_IFINDEX,
SYSFS_DEVATTR_FLAGS,
SYSFS_DEVATTR_ADDR_LEN,
#if 0
SYSFS_DEVATTR_TYPE,
SYSFS_DEVATTR_ADDRESS,
#endif
SYSFS_DEVATTR_BROADCAST,
SYSFS_DEVATTR_NUM
};
struct sysfs_devattr_values
{
char *ifname;
union sysfs_devattr_value value[SYSFS_DEVATTR_NUM];
};
static int sysfs_devattr_ulong_dec(char *ptr, struct sysfs_devattr_values *v, unsigned idx);
static int sysfs_devattr_ulong_hex(char *ptr, struct sysfs_devattr_values *v, unsigned idx);
static int sysfs_devattr_macaddr(char *ptr, struct sysfs_devattr_values *v, unsigned idx);
struct sysfs_devattrs {
const char *name;
int (*handler)(char *ptr, struct sysfs_devattr_values *v, unsigned int idx);
int free;
} sysfs_devattrs[SYSFS_DEVATTR_NUM] = {
[SYSFS_DEVATTR_IFINDEX] = {
.name = "ifindex",
.handler = sysfs_devattr_ulong_dec,
},
[SYSFS_DEVATTR_ADDR_LEN] = {
.name = "addr_len",
.handler = sysfs_devattr_ulong_dec,
},
[SYSFS_DEVATTR_FLAGS] = {
.name = "flags",
.handler = sysfs_devattr_ulong_hex,
},
#if 0
[SYSFS_DEVATTR_TYPE] = {
.name = "type",
.handler = sysfs_devattr_ulong_dec,
},
[SYSFS_DEVATTR_ADDRESS] = {
.name = "address",
.handler = sysfs_devattr_macaddr,
.free = 1,
},
#endif
[SYSFS_DEVATTR_BROADCAST] = {
.name = "broadcast",
.handler = sysfs_devattr_macaddr,
.free = 1,
},
};
#endif
/*
* find_device()
*
* This function checks 1) if the device (if given) is okay for ARP,
* or 2) find fist appropriate device on the system.
*
* Return value:
* >0 : Succeeded, and appropriate device not found.
* device.ifindex remains 0.
* 0 : Succeeded, and approptiate device found.
* device.ifindex is set.
* <0 : Failed. Support not found, or other
* : system error. Try other method.
*
* If an appropriate device found, it is recorded inside the
* "device" variable for later reference.
*
* We have several implementations for this.
* by_ifaddrs(): requires getifaddr() in glibc, and rtnetlink in
* kernel. default and recommended for recent systems.
* by_sysfs(): requires libsysfs , and sysfs in kernel.
* by_ioctl(): unable to list devices without ipv4 address; this
* means, you need to supply the device name for
* DAD purpose.
*/
/* Common check for ifa->ifa_flags */
static int check_ifflags(unsigned int ifflags, int fatal)
{
if (!(ifflags & IFF_UP)) {
if (fatal) {
if (!quiet)
printf("Interface \"%s\" is down\n", device.name);
exit(2);
}
return -1;
}
if (ifflags & (IFF_NOARP | IFF_LOOPBACK)) {
if (fatal) {
if (!quiet)
printf("Interface \"%s\" is not ARPable\n", device.name);
exit(dad ? 0 : 2);
}
return -1;
}
return 0;
}
static int find_device_by_ifaddrs(void)
{
#ifndef WITHOUT_IFADDRS
int rc;
struct ifaddrs *ifa0, *ifa;
int count = 0;
rc = getifaddrs(&ifa0);
if (rc) {
perror("getifaddrs");
return -1;
}
for (ifa = ifa0; ifa; ifa = ifa->ifa_next) {
if (!ifa->ifa_addr)
continue;
if (ifa->ifa_addr->sa_family != AF_PACKET)
continue;
if (device.name && ifa->ifa_name && strcmp(ifa->ifa_name, device.name))
continue;
if (check_ifflags(ifa->ifa_flags, device.name != NULL) < 0)
continue;
if (!((struct sockaddr_ll *)ifa->ifa_addr)->sll_halen)
continue;
if (!ifa->ifa_broadaddr)
continue;
device.ifa = ifa;
if (count++)
break;
}
if (count == 1 && device.ifa) {
device.ifindex = if_nametoindex(device.ifa->ifa_name);
if (!device.ifindex) {
perror("arping: if_nametoindex");
freeifaddrs(ifa0);
return -1;
}
device.name = device.ifa->ifa_name;
return 0;
}
return 1;
#else
return -1;
#endif
}
#ifdef USE_SYSFS
static void sysfs_devattr_values_init(struct sysfs_devattr_values *v, int do_free)
{
int i;
if (do_free) {
free(v->ifname);
for (i = 0; i < SYSFS_DEVATTR_NUM; i++) {
if (sysfs_devattrs[i].free)
free(v->value[i].ptr);
}
}
memset(v, 0, sizeof(*v));
}
static int sysfs_devattr_ulong(char *ptr, struct sysfs_devattr_values *v, unsigned int idx,
unsigned int base)
{
unsigned long *p;
char *ep;
if (!ptr || !v)
return -1;
p = &v->value[idx].ulong;
errno = 0;
*p = strtoul(ptr, &ep, base);
if ((*ptr && isspace(*ptr & 0xff)) || errno || (*ep != '\0' && *ep != '\n'))
goto out;
return 0;
out:
return -1;
}
static int sysfs_devattr_ulong_dec(char *ptr, struct sysfs_devattr_values *v, unsigned int idx)
{
int rc = sysfs_devattr_ulong(ptr, v, idx, 10);
return rc;
}
static int sysfs_devattr_ulong_hex(char *ptr, struct sysfs_devattr_values *v, unsigned int idx)
{
int rc = sysfs_devattr_ulong(ptr, v, idx, 16);
return rc;
}
static int sysfs_devattr_macaddr(char *ptr, struct sysfs_devattr_values *v, unsigned int idx)
{
unsigned char *m;
int i;
unsigned int addrlen;
if (!ptr || !v)
return -1;
addrlen = v->value[SYSFS_DEVATTR_ADDR_LEN].ulong;
m = malloc(addrlen);
for (i = 0; i < addrlen; i++) {
if (i && *(ptr + i * 3 - 1) != ':')
goto out;
if (sscanf(ptr + i * 3, "%02hhx", &m[i]) != 1)
goto out;
}
v->value[idx].ptr = m;
return 0;
out:
free(m);
return -1;
}
#endif
int find_device_by_sysfs(void)
{
int rc = -1;
#ifdef USE_SYSFS
struct sysfs_class *cls_net;
struct dlist *dev_list;
struct sysfs_class_device *dev;
struct sysfs_attribute *dev_attr;
struct sysfs_devattr_values sysfs_devattr_values;
int count = 0;
if (!device.sysfs) {
device.sysfs = malloc(sizeof(*device.sysfs));
sysfs_devattr_values_init(device.sysfs, 0);
}
cls_net = sysfs_open_class("net");
if (!cls_net) {
perror("sysfs_open_class");
return -1;
}
dev_list = sysfs_get_class_devices(cls_net);
if (!dev_list) {
perror("sysfs_get_class_devices");
goto out;
}
sysfs_devattr_values_init(&sysfs_devattr_values, 0);
dlist_for_each_data(dev_list, dev, struct sysfs_class_device) {
int i;
int rc = -1;
if (device.name && strcmp(dev->name, device.name))
goto do_next;
sysfs_devattr_values_init(&sysfs_devattr_values, 1);
for (i = 0; i < SYSFS_DEVATTR_NUM; i++) {
dev_attr = sysfs_get_classdev_attr(dev, sysfs_devattrs[i].name);
if (!dev_attr) {
perror("sysfs_get_classdev_attr");
rc = -1;
break;
}
if (sysfs_read_attribute(dev_attr)) {
perror("sysfs_read_attribute");
rc = -1;
break;
}
rc = sysfs_devattrs[i].handler(dev_attr->value, &sysfs_devattr_values, i);
if (rc < 0)
break;
}
if (rc < 0)
goto do_next;
if (check_ifflags(sysfs_devattr_values.value[SYSFS_DEVATTR_FLAGS].ulong,
device.name != NULL) < 0)
goto do_next;
if (!sysfs_devattr_values.value[SYSFS_DEVATTR_ADDR_LEN].ulong)
goto do_next;
if (device.sysfs->value[SYSFS_DEVATTR_IFINDEX].ulong) {
if (device.sysfs->value[SYSFS_DEVATTR_FLAGS].ulong & IFF_RUNNING)
goto do_next;
}
sysfs_devattr_values.ifname = strdup(dev->name);
if (!sysfs_devattr_values.ifname) {
perror("malloc");
goto out;
}
sysfs_devattr_values_init(device.sysfs, 1);
memcpy(device.sysfs, &sysfs_devattr_values, sizeof(*device.sysfs));
sysfs_devattr_values_init(&sysfs_devattr_values, 0);
if (count++)
break;
continue;
do_next:
sysfs_devattr_values_init(&sysfs_devattr_values, 1);
}
if (count == 1) {
device.ifindex = device.sysfs->value[SYSFS_DEVATTR_IFINDEX].ulong;
device.name = device.sysfs->ifname;
}
rc = !device.ifindex;
out:
sysfs_close_class(cls_net);
#endif
return rc;
}
static int check_device_by_ioctl(int s, struct ifreq *ifr)
{
if (ioctl(s, SIOCGIFFLAGS, ifr) < 0) {
perror("ioctl(SIOCGIFINDEX");
return -1;
}
if (check_ifflags(ifr->ifr_flags, device.name != NULL) < 0)
return 1;
if (ioctl(s, SIOCGIFINDEX, ifr) < 0) {
perror("ioctl(SIOCGIFINDEX");
return -1;
}
return 0;
}
static int find_device_by_ioctl(void)
{
int s;
struct ifreq *ifr0, *ifr, *ifr_end;
size_t ifrsize = sizeof(*ifr);
struct ifconf ifc;
static struct ifreq ifrbuf;
int count = 0;
s = socket(AF_INET, SOCK_DGRAM, 0);
if (s < 0) {
perror("socket");
return -1;
}
memset(&ifrbuf, 0, sizeof(ifrbuf));
if (device.name) {
strncpy(ifrbuf.ifr_name, device.name, sizeof(ifrbuf.ifr_name) - 1);
if (check_device_by_ioctl(s, &ifrbuf))
goto out;
count++;
} else {
do {
int rc;
ifr0 = malloc(ifrsize);
if (!ifr0) {
perror("malloc");
goto out;
}
ifc.ifc_buf = (char *)ifr0;
ifc.ifc_len = ifrsize;
rc = ioctl(s, SIOCGIFCONF, &ifc);
if (rc < 0) {
perror("ioctl(SIOCFIFCONF");
goto out;
}
if (ifc.ifc_len + sizeof(*ifr0) + sizeof(struct sockaddr_storage) - sizeof(struct sockaddr) <= ifrsize)
break;
ifrsize *= 2;
free(ifr0);
ifr0 = NULL;
} while(ifrsize < INT_MAX / 2);
if (!ifr0) {
fprintf(stderr, "arping: too many interfaces!?\n");
goto out;
}
ifr_end = (struct ifreq *)(((char *)ifr0) + ifc.ifc_len - sizeof(*ifr0));
for (ifr = ifr0; ifr <= ifr_end; ifr++) {
if (check_device_by_ioctl(s, &ifrbuf))
continue;
memcpy(&ifrbuf.ifr_name, ifr->ifr_name, sizeof(ifrbuf.ifr_name));
if (count++)
break;
}
}
close(s);
if (count == 1) {
device.ifindex = ifrbuf.ifr_ifindex;
device.name = ifrbuf.ifr_name;
}
return !device.ifindex;
out:
close(s);
return -1;
}
static int find_device(void)
{
int rc;
rc = find_device_by_ifaddrs();
if (rc >= 0)
goto out;
rc = find_device_by_sysfs();
if (rc >= 0)
goto out;
rc = find_device_by_ioctl();
out:
return rc;
}
/*
* set_device_broadcast()
*
* This fills the device "broadcast address"
* based on information found by find_device() funcion.
*/
static int set_device_broadcast_ifaddrs_one(struct device *device, unsigned char *ba, size_t balen, int fatal)
{
#ifndef WITHOUT_IFADDRS
struct ifaddrs *ifa;
struct sockaddr_ll *sll;
if (!device)
return -1;
ifa = device->ifa;
if (!ifa)
return -1;
sll = (struct sockaddr_ll *)ifa->ifa_broadaddr;
if (sll->sll_halen != balen) {
if (fatal) {
if (!quiet)
printf("Address length does not match...\n");
exit(2);
}
return -1;
}
memcpy(ba, sll->sll_addr, sll->sll_halen);
return 0;
#else
return -1;
#endif
}
int set_device_broadcast_sysfs(struct device *device, unsigned char *ba, size_t balen)
{
#ifdef USE_SYSFS
struct sysfs_devattr_values *v;
if (!device)
return -1;
v = device->sysfs;
if (!v)
return -1;
if (v->value[SYSFS_DEVATTR_ADDR_LEN].ulong != balen)
return -1;
memcpy(ba, v->value[SYSFS_DEVATTR_BROADCAST].ptr, balen);
return 0;
#else
return -1;
#endif
}
static int set_device_broadcast_fallback(struct device *device, unsigned char *ba, size_t balen)
{
if (!quiet)
fprintf(stderr, "WARNING: using default broadcast address.\n");
memset(ba, -1, balen);
return 0;
}
static void set_device_broadcast(struct device *dev, unsigned char *ba, size_t balen)
{
if (!set_device_broadcast_ifaddrs_one(dev, ba, balen, 0))
return;
if (!set_device_broadcast_sysfs(dev, ba, balen))
return;
set_device_broadcast_fallback(dev, ba, balen);
}
int
main(int argc, char **argv)
{
int socket_errno;
int ch;
limit_capabilities();
#ifdef USE_IDN
setlocale(LC_ALL, "");
#endif
enable_capability_raw();
s = socket(PF_PACKET, SOCK_DGRAM, 0);
socket_errno = errno;
disable_capability_raw();
while ((ch = getopt(argc, argv, "h?bfDUAqc:w:s:I:V")) != EOF) {
switch(ch) {
case 'b':
broadcast_only=1;
break;
case 'D':
dad++;
quit_on_reply=1;
break;
case 'U':
unsolicited++;
break;
case 'A':
advert++;
unsolicited++;
break;
case 'q':
quiet++;
break;
case 'c':
count = atoi(optarg);
break;
case 'w':
timeout = atoi(optarg);
break;
case 'I':
device.name = optarg;
break;
case 'f':
quit_on_reply=1;
break;
case 's':
source = optarg;
break;
case 'V':
printf("arping utility, iputils-%s\n", SNAPSHOT);
exit(0);
case 'h':
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
target = *argv;
if (device.name && !*device.name)
device.name = NULL;
if (s < 0) {
errno = socket_errno;
perror("arping: socket");
exit(2);
}
if (find_device() < 0)
exit(2);
if (!device.ifindex) {
if (device.name) {
fprintf(stderr, "arping: Device %s not available.\n", device.name);
exit(2);
}
fprintf(stderr, "arping: device (option -I) is required.\n");
usage();
}
if (inet_aton(target, &dst) != 1) {
struct hostent *hp;
char *idn = target;
#ifdef USE_IDN
int rc;
rc = idna_to_ascii_lz(target, &idn, 0);
if (rc != IDNA_SUCCESS) {
fprintf(stderr, "arping: IDN encoding failed: %s\n", idna_strerror(rc));
exit(2);
}
#endif
hp = gethostbyname2(idn, AF_INET);
if (!hp) {
fprintf(stderr, "arping: unknown host %s\n", target);
exit(2);
}
#ifdef USE_IDN
free(idn);
#endif
memcpy(&dst, hp->h_addr, 4);
}
if (source && inet_aton(source, &src) != 1) {
fprintf(stderr, "arping: invalid source %s\n", source);
exit(2);
}
if (!dad && unsolicited && src.s_addr == 0)
src = dst;
if (!dad || src.s_addr) {
struct sockaddr_in saddr;
int probe_fd = socket(AF_INET, SOCK_DGRAM, 0);
if (probe_fd < 0) {
perror("socket");
exit(2);
}
if (device.name) {
enable_capability_raw();
if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device.name, strlen(device.name)+1) == -1)
perror("WARNING: interface is ignored");
disable_capability_raw();
}
memset(&saddr, 0, sizeof(saddr));
saddr.sin_family = AF_INET;
if (src.s_addr) {
saddr.sin_addr = src;
if (bind(probe_fd, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {
perror("bind");
exit(2);
}
} else if (!dad) {
int on = 1;
socklen_t alen = sizeof(saddr);
saddr.sin_port = htons(1025);
saddr.sin_addr = dst;
if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, (char*)&on, sizeof(on)) == -1)
perror("WARNING: setsockopt(SO_DONTROUTE)");
if (connect(probe_fd, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {
perror("connect");
exit(2);
}
if (getsockname(probe_fd, (struct sockaddr*)&saddr, &alen) == -1) {
perror("getsockname");
exit(2);
}
src = saddr.sin_addr;
}
close(probe_fd);
};
((struct sockaddr_ll *)&me)->sll_family = AF_PACKET;
((struct sockaddr_ll *)&me)->sll_ifindex = device.ifindex;
((struct sockaddr_ll *)&me)->sll_protocol = htons(ETH_P_ARP);
if (bind(s, (struct sockaddr*)&me, sizeof(me)) == -1) {
perror("bind");
exit(2);
}
if (1) {
socklen_t alen = sizeof(me);
if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {
perror("getsockname");
exit(2);
}
}
if (((struct sockaddr_ll *)&me)->sll_halen == 0) {
if (!quiet)
printf("Interface \"%s\" is not ARPable (no ll address)\n", device.name);
exit(dad?0:2);
}
he = me;
set_device_broadcast(&device, ((struct sockaddr_ll *)&he)->sll_addr,
((struct sockaddr_ll *)&he)->sll_halen);
if (!quiet) {
printf("ARPING %s ", inet_ntoa(dst));
printf("from %s %s\n", inet_ntoa(src), device.name ? : "");
}
if (!src.s_addr && !dad) {
fprintf(stderr, "arping: no source address in not-DAD mode\n");
exit(2);
}
drop_capabilities();
set_signal(SIGINT, finish);
set_signal(SIGALRM, catcher);
catcher();
while(1) {
sigset_t sset, osset;
unsigned char packet[4096];
struct sockaddr_storage from;
socklen_t alen = sizeof(from);
int cc;
if ((cc = recvfrom(s, packet, sizeof(packet), 0,
(struct sockaddr *)&from, &alen)) < 0) {
perror("arping: recvfrom");
continue;
}
sigemptyset(&sset);
sigaddset(&sset, SIGALRM);
sigaddset(&sset, SIGINT);
sigprocmask(SIG_BLOCK, &sset, &osset);
recv_pack(packet, cc, (struct sockaddr_ll *)&from);
sigprocmask(SIG_SETMASK, &osset, NULL);
}
}