/* vi: set sw=4 ts=4: */
/*
- * arping.c - Ping hosts by ARP requests/replies
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
- *
- * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
* Busybox port: Nick Fedchik <nick@fedchik.org.ua>
*/
+//usage:#define arping_trivial_usage
+//usage: "[-fqbDUA] [-c CNT] [-w TIMEOUT] [-I IFACE] [-s SRC_IP] DST_IP"
+//usage:#define arping_full_usage "\n\n"
+//usage: "Send ARP requests/replies\n"
+//usage: "\n -f Quit on first ARP reply"
+//usage: "\n -q Quiet"
+//usage: "\n -b Keep broadcasting, don't go unicast"
+//usage: "\n -D Duplicated address detection mode"
+//usage: "\n -U Unsolicited ARP mode, update your neighbors"
+//usage: "\n -A ARP answer mode, update your neighbors"
+//usage: "\n -c N Stop after sending N ARP requests"
+//usage: "\n -w TIMEOUT Time to wait for ARP reply, seconds"
+//usage: "\n -I IFACE Interface to use (default eth0)"
+//usage: "\n -s SRC_IP Sender IP address"
+//usage: "\n DST_IP Target IP address"
+
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/ether.h>
/* We don't expect to see 1000+ seconds delay, unsigned is enough */
#define MONOTONIC_US() ((unsigned)monotonic_us())
-static struct in_addr src;
-static struct in_addr dst;
-static struct sockaddr_ll me;
-static struct sockaddr_ll he;
-static unsigned last;
-
enum {
DAD = 1,
UNSOLICITED = 2,
UNICASTING = 64
};
-static int sock;
-static unsigned count = UINT_MAX;
-static unsigned timeout_us;
-static unsigned sent;
-static unsigned brd_sent;
-static unsigned received;
-static unsigned brd_recv;
-static unsigned req_recv;
+struct globals {
+ struct in_addr src;
+ struct in_addr dst;
+ struct sockaddr_ll me;
+ struct sockaddr_ll he;
+ int sock_fd;
+
+ int count; // = -1;
+ unsigned last;
+ unsigned timeout_us;
+ unsigned start;
+
+ unsigned sent;
+ unsigned brd_sent;
+ unsigned received;
+ unsigned brd_recv;
+ unsigned req_recv;
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define src (G.src )
+#define dst (G.dst )
+#define me (G.me )
+#define he (G.he )
+#define sock_fd (G.sock_fd )
+#define count (G.count )
+#define last (G.last )
+#define timeout_us (G.timeout_us)
+#define start (G.start )
+#define sent (G.sent )
+#define brd_sent (G.brd_sent )
+#define received (G.received )
+#define brd_recv (G.brd_recv )
+#define req_recv (G.req_recv )
+#define INIT_G() do { \
+ count = -1; \
+} while (0)
+
+// If GNUisms are not available...
+//static void *mempcpy(void *_dst, const void *_src, int n)
+//{
+// memcpy(_dst, _src, n);
+// return (char*)_dst + n;
+//}
static int send_pack(struct in_addr *src_addr,
struct in_addr *dst_addr, struct sockaddr_ll *ME,
struct sockaddr_ll *HE)
{
int err;
- unsigned 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);
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 = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
- memcpy(p, &ME->sll_addr, ah->ar_hln);
- p += ME->sll_halen;
-
- memcpy(p, src_addr, 4);
- p += 4;
+ p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
+ p = mempcpy(p, src_addr, 4);
if (option_mask32 & ADVERT)
- memcpy(p, &ME->sll_addr, ah->ar_hln);
+ p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
else
- memcpy(p, &HE->sll_addr, ah->ar_hln);
- p += ah->ar_hln;
+ p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
- memcpy(p, dst_addr, 4);
- p += 4;
+ p = mempcpy(p, dst_addr, 4);
- now = MONOTONIC_US();
- err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
+ err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
if (err == p - buf) {
- last = now;
+ last = MONOTONIC_US();
sent++;
if (!(option_mask32 & UNICASTING))
brd_sent++;
return err;
}
-static void finish(void) ATTRIBUTE_NORETURN;
+static void finish(void) NORETURN;
static void finish(void)
{
if (!(option_mask32 & QUIET)) {
if (option_mask32 & DAD)
exit(!!received);
if (option_mask32 & UNSOLICITED)
- exit(0);
+ exit(EXIT_SUCCESS);
exit(!received);
}
static void catcher(void)
{
- static unsigned start;
-
unsigned now;
now = MONOTONIC_US();
if (start == 0)
start = now;
- if (count == 0 || (timeout_us && (now - start) > (timeout_us + 500000)))
+ if (count == 0 || (timeout_us && (now - start) > timeout_us))
finish();
- count--;
+ /* count < 0 means "infinite count" */
+ if (count > 0)
+ count--;
if (last == 0 || (now - last) > 500000) {
send_pack(&src, &dst, &me, &he);
alarm(1);
}
-static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
+static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
{
struct arphdr *ah = (struct arphdr *) buf;
unsigned char *p = (unsigned char *) (ah + 1);
struct in_addr src_ip, dst_ip;
+ /* moves below assume in_addr is 4 bytes big, ensure that */
+ struct BUG_in_addr_must_be_4 {
+ char BUG_in_addr_must_be_4[
+ sizeof(struct in_addr) == 4 ? 1 : -1
+ ];
+ char BUG_s_addr_must_be_4[
+ sizeof(src_ip.s_addr) == 4 ? 1 : -1
+ ];
+ };
/* Filter out wild packets */
if (FROM->sll_pkttype != PACKET_HOST
&& FROM->sll_pkttype != PACKET_BROADCAST
&& FROM->sll_pkttype != PACKET_MULTICAST)
- return 0;
+ return false;
- /* Only these types are recognised */
+ /* Only these types are recognized */
if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
- return 0;
+ return false;
/* 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;
+ return false;
/* 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 != 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 (ah->ar_pro != htons(ETH_P_IP)
+ || (ah->ar_pln != 4)
+ || (ah->ar_hln != me.sll_halen)
+ || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
+ return false;
+
+ move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
+ move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
+
+ if (dst.s_addr != src_ip.s_addr)
+ return false;
if (!(option_mask32 & 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, &me.sll_addr, ah->ar_hln))
- return 0;
+ if ((src.s_addr != dst_ip.s_addr)
+ || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
+ return false;
} else {
/* DAD packet was:
src_ip = 0 (or some src)
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, &me.sll_addr, me.sll_halen) == 0)
- return 0;
- if (src.s_addr && src.s_addr != dst_ip.s_addr)
- return 0;
+ if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
+ || (src.s_addr && src.s_addr != dst_ip.s_addr))
+ return false;
}
if (!(option_mask32 & QUIET)) {
int s_printed = 0;
}
if (last) {
- printf(" %u.%03ums\n", last / 1000, last % 1000);
+ unsigned diff = MONOTONIC_US() - last;
+ printf(" %u.%03ums\n", diff / 1000, diff % 1000);
} else {
printf(" UNSOLICITED?\n");
}
- fflush(stdout);
+ fflush_all();
}
received++;
if (FROM->sll_pkttype != PACKET_HOST)
memcpy(he.sll_addr, p, me.sll_halen);
option_mask32 |= UNICASTING;
}
- return 1;
+ return true;
}
-int arping_main(int argc, char **argv);
-int arping_main(int argc, char **argv)
+int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int arping_main(int argc UNUSED_PARAM, char **argv)
{
const char *device = "eth0";
- int ifindex;
char *source = NULL;
char *target;
unsigned char *packet;
+ char *err_str;
- sock = xsocket(PF_PACKET, SOCK_DGRAM, 0);
+ INIT_G();
+
+ sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
// Drop suid root privileges
- xsetuid(getuid());
+ // Need to remove SUID_NEVER from applets.h for this to work
+ //xsetuid(getuid());
+ err_str = xasprintf("interface %s %%s", device);
{
unsigned opt;
- char *str_count, *str_timeout;
+ char *str_timeout;
/* Dad also sets quit_on_reply.
* Advert also sets unsolicited.
*/
- opt_complementary = "=1:Df:AU";
- opt = getopt32(argc, argv, "DUAqfbc:w:I:s:",
- &str_count, &str_timeout, &device, &source);
- if (opt & 0x40) /* -c: count */
- count = xatou(str_count);
+ opt_complementary = "=1:Df:AU:c+";
+ opt = getopt32(argv, "DUAqfbc:w:I:s:",
+ &count, &str_timeout, &device, &source);
if (opt & 0x80) /* -w: timeout */
- timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000;
- //if (opt & 0x100) /* -I: interface */
- if (strlen(device) >= IF_NAMESIZE) {
- bb_error_msg_and_die("interface name '%s' is too long",
- device);
- }
+ timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
//if (opt & 0x200) /* -s: source */
option_mask32 &= 0x3f; /* set respective flags */
}
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
- ioctl_or_perror_and_die(sock, SIOCGIFINDEX, &ifr, "interface %s not found", device);
- ifindex = ifr.ifr_ifindex;
+ strncpy_IFNAMSIZ(ifr.ifr_name, device);
+ /* We use ifr.ifr_name in error msg so that problem
+ * with truncated name will be visible */
+ ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
+ me.sll_ifindex = ifr.ifr_ifindex;
- xioctl(sock, SIOCGIFFLAGS, (char *) &ifr);
+ xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
if (!(ifr.ifr_flags & IFF_UP)) {
- bb_error_msg_and_die("interface %s is down", device);
+ bb_error_msg_and_die(err_str, "is down");
}
if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
- bb_error_msg("interface %s is not ARPable", device);
+ bb_error_msg(err_str, "is not ARPable");
return (option_mask32 & DAD ? 0 : 2);
}
}
- if (!inet_aton(target, &dst)) {
+ /* if (!inet_aton(target, &dst)) - not needed */ {
len_and_sockaddr *lsa;
lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
- memcpy(&dst, &lsa->sin.sin_addr.s_addr, 4);
+ dst = lsa->u.sin.sin_addr;
if (ENABLE_FEATURE_CLEAN_UP)
free(lsa);
}
bb_error_msg_and_die("invalid source address %s", source);
}
- if (!(option_mask32 & DAD) && (option_mask32 & UNSOLICITED) && src.s_addr == 0)
+ if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
src = dst;
if (!(option_mask32 & DAD) || src.s_addr) {
struct sockaddr_in saddr;
int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
- if (device) {
- if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1)
- bb_error_msg("warning: interface %s is ignored", device);
- }
+ setsockopt_bindtodevice(probe_fd, device);
memset(&saddr, 0, sizeof(saddr));
saddr.sin_family = AF_INET;
if (src.s_addr) {
+ /* Check that this is indeed our IP */
saddr.sin_addr = src;
xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
- } else if (!(option_mask32 & DAD)) {
+ } else { /* !(option_mask32 & DAD) case */
+ /* Find IP address on this iface */
socklen_t alen = sizeof(saddr);
saddr.sin_port = htons(1025);
saddr.sin_addr = dst;
if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
- bb_perror_msg("warning: setsockopt(SO_DONTROUTE)");
+ bb_perror_msg("setsockopt(SO_DONTROUTE)");
xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
- if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) {
- bb_error_msg_and_die("getsockname");
- }
+ getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
+ //never happens:
+ //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
+ // bb_perror_msg_and_die("getsockname");
+ if (saddr.sin_family != AF_INET)
+ bb_error_msg_and_die("no IP address configured");
src = saddr.sin_addr;
}
close(probe_fd);
}
me.sll_family = AF_PACKET;
- me.sll_ifindex = ifindex;
+ //me.sll_ifindex = ifindex; - done before
me.sll_protocol = htons(ETH_P_ARP);
- xbind(sock, (struct sockaddr *) &me, sizeof(me));
+ xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
{
socklen_t alen = sizeof(me);
-
- if (getsockname(sock, (struct sockaddr *) &me, &alen) == -1) {
- bb_error_msg_and_die("getsockname");
- }
+ getsockname(sock_fd, (struct sockaddr *) &me, &alen);
+ //never happens:
+ //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
+ // bb_perror_msg_and_die("getsockname");
}
if (me.sll_halen == 0) {
- bb_error_msg("interface \"%s\" is not ARPable (no ll address)", device);
+ bb_error_msg(err_str, "is not ARPable (no ll address)");
return (option_mask32 & DAD ? 0 : 2);
}
he = me;
memset(he.sll_addr, -1, he.sll_halen);
if (!(option_mask32 & QUIET)) {
- printf("ARPING to %s from %s via %s\n",
- inet_ntoa(dst), inet_ntoa(src),
- device ? device : "unknown");
- }
-
- if (!src.s_addr && !(option_mask32 & DAD)) {
- bb_error_msg_and_die("no src address in the non-DAD mode");
+ /* inet_ntoa uses static storage, can't use in same printf */
+ printf("ARPING to %s", inet_ntoa(dst));
+ printf(" from %s via %s\n", inet_ntoa(src), device);
}
- {
- struct sigaction sa;
-
- memset(&sa, 0, sizeof(sa));
- sa.sa_flags = SA_RESTART;
-
- sa.sa_handler = (void (*)(int)) finish;
- sigaction(SIGINT, &sa, NULL);
-
- sa.sa_handler = (void (*)(int)) catcher;
- sigaction(SIGALRM, &sa, NULL);
- }
+ signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
+ signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
catcher();
socklen_t alen = sizeof(from);
int cc;
- cc = recvfrom(sock, packet, 4096, 0, (struct sockaddr *) &from, &alen);
+ cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
if (cc < 0) {
bb_perror_msg("recvfrom");
continue;