busybox/networking/arp.c

/* vi: set sw=4 ts=4: */
/*
 * arp.c - Manipulate the system ARP cache
 *
 * 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.
 *
 * Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org>
 * Busybox port: Paul van Gool <pvangool at mimotech.com>
 *
 * modified for getopt32 by Arne Bernin <arne [at] alamut.de>
 */

#include "libbb.h"
#include "inet_common.h"

#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/ether.h>
#include <netpacket/packet.h>

#define DEBUG 0

#define DFLT_AF "inet"
#define DFLT_HW "ether"

#define	ARP_OPT_A (0x1)
#define	ARP_OPT_p (0x2)
#define	ARP_OPT_H (0x4)
#define	ARP_OPT_t (0x8)
#define	ARP_OPT_i (0x10)
#define	ARP_OPT_a (0x20)
#define	ARP_OPT_d (0x40)
#define	ARP_OPT_n (0x80)	/* do not resolve addresses     */
#define	ARP_OPT_D (0x100)	/* HW-address is devicename     */
#define	ARP_OPT_s (0x200)
#define	ARP_OPT_v (0x400 * DEBUG)	/* debugging output flag        */


static const struct aftype *ap; /* current address family       */
static const struct hwtype *hw; /* current hardware type        */
static int sockfd;              /* active socket descriptor     */
static smallint hw_set;         /* flag if hw-type was set (-H) */
static const char *device = ""; /* current device               */

static const char options[] ALIGN1 =
	"pub\0"
	"priv\0"
	"temp\0"
	"trail\0"
	"dontpub\0"
	"auto\0"
	"dev\0"
	"netmask\0";

/* Delete an entry from the ARP cache. */
/* Called only from main, once */
static int arp_del(char **args)
{
	char *host;
	struct arpreq req;
	struct sockaddr sa;
	int flags = 0;
	int err;

	memset(&req, 0, sizeof(req));

	/* Resolve the host name. */
	host = *args;
	if (ap->input(host, &sa) < 0) {
		bb_herror_msg_and_die("%s", host);
	}

	/* If a host has more than one address, use the correct one! */
	memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));

	if (hw_set)
		req.arp_ha.sa_family = hw->type;

	req.arp_flags = ATF_PERM;
	args++;
	while (*args != NULL) {
		switch (index_in_strings(options, *args)) {
		case 0: /* "pub" */
			flags |= 1;
			args++;
			break;
		case 1: /* "priv" */
			flags |= 2;
			args++;
			break;
		case 2: /* "temp" */
			req.arp_flags &= ~ATF_PERM;
			args++;
			break;
		case 3: /* "trail" */
			req.arp_flags |= ATF_USETRAILERS;
			args++;
			break;
		case 4: /* "dontpub" */
#ifdef HAVE_ATF_DONTPUB
			req.arp_flags |= ATF_DONTPUB;
#else
			bb_error_msg("feature ATF_DONTPUB is not supported");
#endif
			args++;
			break;
		case 5: /* "auto" */
#ifdef HAVE_ATF_MAGIC
			req.arp_flags |= ATF_MAGIC;
#else
			bb_error_msg("feature ATF_MAGIC is not supported");
#endif
			args++;
			break;
		case 6: /* "dev" */
			if (*++args == NULL)
				bb_show_usage();
			device = *args;
			args++;
			break;
		case 7: /* "netmask" */
			if (*++args == NULL)
				bb_show_usage();
			if (strcmp(*args, "255.255.255.255") != 0) {
				host = *args;
				if (ap->input(host, &sa) < 0) {
					bb_herror_msg_and_die("%s", host);
				}
				memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
				req.arp_flags |= ATF_NETMASK;
			}
			args++;
			break;
		default:
			bb_show_usage();
			break;
		}
	}
	if (flags == 0)
		flags = 3;

	strncpy(req.arp_dev, device, sizeof(req.arp_dev));

	err = -1;

	/* Call the kernel. */
	if (flags & 2) {
		if (option_mask32 & ARP_OPT_v)
			bb_error_msg("SIOCDARP(nopub)");
		err = ioctl(sockfd, SIOCDARP, &req);
		if (err < 0) {
			if (errno == ENXIO) {
				if (flags & 1)
					goto nopub;
				printf("No ARP entry for %s\n", host);
				return -1;
			}
			bb_perror_msg_and_die("SIOCDARP(priv)");
		}
	}
	if ((flags & 1) && err) {
 nopub:
		req.arp_flags |= ATF_PUBL;
		if (option_mask32 & ARP_OPT_v)
			bb_error_msg("SIOCDARP(pub)");
		if (ioctl(sockfd, SIOCDARP, &req) < 0) {
			if (errno == ENXIO) {
				printf("No ARP entry for %s\n", host);
				return -1;
			}
			bb_perror_msg_and_die("SIOCDARP(pub)");
		}
	}
	return 0;
}

/* Get the hardware address to a specified interface name */
static void arp_getdevhw(char *ifname, struct sockaddr *sa,
						 const struct hwtype *hwt)
{
	struct ifreq ifr;
	const struct hwtype *xhw;

	strcpy(ifr.ifr_name, ifname);
	ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
					"cant get HW-Address for '%s'", ifname);
	if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) {
		bb_error_msg_and_die("protocol type mismatch");
	}
	memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));

	if (option_mask32 & ARP_OPT_v) {
		xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
		if (!xhw || !xhw->print) {
			xhw = get_hwntype(-1);
		}
		bb_error_msg("device '%s' has HW address %s '%s'",
					 ifname, xhw->name,
					 xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
	}
}

/* Set an entry in the ARP cache. */
/* Called only from main, once */
static int arp_set(char **args)
{
	char *host;
	struct arpreq req;
	struct sockaddr sa;
	int flags;

	memset(&req, 0, sizeof(req));

	host = *args++;
	if (ap->input(host, &sa) < 0) {
		bb_herror_msg_and_die("%s", host);
	}
	/* If a host has more than one address, use the correct one! */
	memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));

	/* Fetch the hardware address. */
	if (*args == NULL) {
		bb_error_msg_and_die("need hardware address");
	}
	if (option_mask32 & ARP_OPT_D) {
		arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL);
	} else {
		if (hw->input(*args++, &req.arp_ha) < 0) {
			bb_error_msg_and_die("invalid hardware address");
		}
	}

	/* Check out any modifiers. */
	flags = ATF_PERM | ATF_COM;
	while (*args != NULL) {
		switch (index_in_strings(options, *args)) {
		case 0: /* "pub" */
			flags |= ATF_PUBL;
			args++;
			break;
		case 1: /* "priv" */
			flags &= ~ATF_PUBL;
			args++;
			break;
		case 2: /* "temp" */
			flags &= ~ATF_PERM;
			args++;
			break;
		case 3: /* "trail" */
			flags |= ATF_USETRAILERS;
			args++;
			break;
		case 4: /* "dontpub" */
#ifdef HAVE_ATF_DONTPUB
			flags |= ATF_DONTPUB;
#else
			bb_error_msg("feature ATF_DONTPUB is not supported");
#endif
			args++;
			break;
		case 5: /* "auto" */
#ifdef HAVE_ATF_MAGIC
			flags |= ATF_MAGIC;
#else
			bb_error_msg("feature ATF_MAGIC is not supported");
#endif
			args++;
			break;
		case 6: /* "dev" */
			if (*++args == NULL)
				bb_show_usage();
			device = *args;
			args++;
			break;
		case 7: /* "netmask" */
			if (*++args == NULL)
				bb_show_usage();
			if (strcmp(*args, "255.255.255.255") != 0) {
				host = *args;
				if (ap->input(host, &sa) < 0) {
					bb_herror_msg_and_die("%s", host);
				}
				memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
				flags |= ATF_NETMASK;
			}
			args++;
			break;
		default:
			bb_show_usage();
			break;
		}
	}

	/* Fill in the remainder of the request. */
	req.arp_flags = flags;

	strncpy(req.arp_dev, device, sizeof(req.arp_dev));

	/* Call the kernel. */
	if (option_mask32 & ARP_OPT_v)
		bb_error_msg("SIOCSARP()");
	xioctl(sockfd, SIOCSARP, &req);
	return 0;
}


/* Print the contents of an ARP request block. */
static void
arp_disp(const char *name, char *ip, int type, int arp_flags,
		 char *hwa, char *mask, char *dev)
{
	static const int arp_masks[] = {
		ATF_PERM, ATF_PUBL,
#ifdef HAVE_ATF_MAGIC
		ATF_MAGIC,
#endif
#ifdef HAVE_ATF_DONTPUB
		ATF_DONTPUB,
#endif
		ATF_USETRAILERS,
	};
	static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
#ifdef HAVE_ATF_MAGIC
		"AUTO\0"
#endif
#ifdef HAVE_ATF_DONTPUB
		"DONTPUB\0"
#endif
		"TRAIL\0"
	;

	const struct hwtype *xhw;

	xhw = get_hwntype(type);
	if (xhw == NULL)
		xhw = get_hwtype(DFLT_HW);

	printf("%s (%s) at ", name, ip);

	if (!(arp_flags & ATF_COM)) {
		if (arp_flags & ATF_PUBL)
			printf("* ");
		else
			printf("<incomplete> ");
	} else {
		printf("%s [%s] ", hwa, xhw->name);
	}

	if (arp_flags & ATF_NETMASK)
		printf("netmask %s ", mask);

	print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
	printf(" on %s\n", dev);
}

/* Display the contents of the ARP cache in the kernel. */
/* Called only from main, once */
static int arp_show(char *name)
{
	const char *host;
	const char *hostname;
	FILE *fp;
	struct sockaddr sa;
	int type, flags;
	int num;
	unsigned entries = 0, shown = 0;
	char ip[128];
	char hwa[128];
	char mask[128];
	char line[128];
	char dev[128];

	host = NULL;
	if (name != NULL) {
		/* Resolve the host name. */
		if (ap->input(name, &sa) < 0) {
			bb_herror_msg_and_die("%s", name);
		}
		host = xstrdup(ap->sprint(&sa, 1));
	}
	fp = xfopen_for_read("/proc/net/arp");
	/* Bypass header -- read one line */
	fgets(line, sizeof(line), fp);

	/* Read the ARP cache entries. */
	while (fgets(line, sizeof(line), fp)) {

		mask[0] = '-'; mask[1] = '\0';
		dev[0] = '-'; dev[1] = '\0';
		/* All these strings can't overflow
		 * because fgets above reads limited amount of data */
		num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
					 ip, &type, &flags, hwa, mask, dev);
		if (num < 4)
			break;

		entries++;
		/* if the user specified hw-type differs, skip it */
		if (hw_set && (type != hw->type))
			continue;

		/* if the user specified address differs, skip it */
		if (host && strcmp(ip, host) != 0)
			continue;

		/* if the user specified device differs, skip it */
		if (device[0] && strcmp(dev, device) != 0)
			continue;

		shown++;
		/* This IS ugly but it works -be */
		hostname = "?";
		if (!(option_mask32 & ARP_OPT_n)) {
			if (ap->input(ip, &sa) < 0)
				hostname = ip;
			else
				hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000);
			if (strcmp(hostname, ip) == 0)
				hostname = "?";
		}

		arp_disp(hostname, ip, type, flags, hwa, mask, dev);
	}
	if (option_mask32 & ARP_OPT_v)
		printf("Entries: %d\tSkipped: %d\tFound: %d\n",
			   entries, entries - shown, shown);

	if (!shown) {
		if (hw_set || host || device[0])
			printf("No match found in %d entries\n", entries);
	}
	if (ENABLE_FEATURE_CLEAN_UP) {
		free((char*)host);
		fclose(fp);
	}
	return 0;
}

int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int arp_main(int argc UNUSED_PARAM, char **argv)
{
	const char *hw_type = "ether";
	const char *protocol;

	/* Initialize variables... */
	ap = get_aftype(DFLT_AF);
	if (!ap)
		bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");

	getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
				 &hw_type, &hw_type, &device);
	argv += optind;
	if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) {
		ap = get_aftype(protocol);
		if (ap == NULL)
			bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
	}
	if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) {
		hw = get_hwtype(hw_type);
		if (hw == NULL)
			bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
		hw_set = 1;
	}
	//if (option_mask32 & ARP_OPT_i)... -i

	if (ap->af != AF_INET) {
		bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
	}

	/* If no hw type specified get default */
	if (!hw) {
		hw = get_hwtype(DFLT_HW);
		if (!hw)
			bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
	}

	if (hw->alen <= 0) {
		bb_error_msg_and_die("%s: %s without ARP support",
							 hw->name, "hardware type");
	}
	sockfd = xsocket(AF_INET, SOCK_DGRAM, 0);

	/* Now see what we have to do here... */
	if (option_mask32 & (ARP_OPT_d|ARP_OPT_s)) {
		if (argv[0] == NULL)
			bb_error_msg_and_die("need host name");
		if (option_mask32 & ARP_OPT_s)
			return arp_set(argv);
		return arp_del(argv);
	}
	//if (option_mask32 & ARP_OPT_a) - default
	return arp_show(argv[0]);
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* arp.c - Manipulate the system ARP cache
4	*
5	* This program is free software; you can redistribute it and/or
6	* modify it under the terms of the GNU General Public License
7	* as published by the Free Software Foundation; either version
8	* 2 of the License, or (at your option) any later version.
9	*
10	* Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org>
11	* Busybox port: Paul van Gool <pvangool at mimotech.com>
12	*
13	* modified for getopt32 by Arne Bernin <arne [at] alamut.de>
14	*/
15
16	#include "libbb.h"
17	#include "inet_common.h"
18
19	#include <arpa/inet.h>
20	#include <net/if.h>
21	#include <net/if_arp.h>
22	#include <netinet/ether.h>
23	#include <netpacket/packet.h>
24
25	#define DEBUG 0
26
27	#define DFLT_AF "inet"
28	#define DFLT_HW "ether"
29
30	#define ARP_OPT_A (0x1)
31	#define ARP_OPT_p (0x2)
32	#define ARP_OPT_H (0x4)
33	#define ARP_OPT_t (0x8)
34	#define ARP_OPT_i (0x10)
35	#define ARP_OPT_a (0x20)
36	#define ARP_OPT_d (0x40)
37	#define ARP_OPT_n (0x80) /* do not resolve addresses */
38	#define ARP_OPT_D (0x100) /* HW-address is devicename */
39	#define ARP_OPT_s (0x200)
40	#define ARP_OPT_v (0x400 * DEBUG) /* debugging output flag */
41
42
43	static const struct aftype ap; / current address family */
44	static const struct hwtype hw; / current hardware type */
45	static int sockfd; /* active socket descriptor */
46	static smallint hw_set; /* flag if hw-type was set (-H) */
47	static const char device = ""; / current device */
48
49	static const char options[] ALIGN1 =
50	"pub\0"
51	"priv\0"
52	"temp\0"
53	"trail\0"
54	"dontpub\0"
55	"auto\0"
56	"dev\0"
57	"netmask\0";
58
59	/* Delete an entry from the ARP cache. */
60	/* Called only from main, once */
61	static int arp_del(char **args)
62	{
63	char *host;
64	struct arpreq req;
65	struct sockaddr sa;
66	int flags = 0;
67	int err;
68
69	memset(&req, 0, sizeof(req));
70
71	/* Resolve the host name. */
72	host = *args;
73	if (ap->input(host, &sa) < 0) {
74	bb_herror_msg_and_die("%s", host);
75	}
76
77	/* If a host has more than one address, use the correct one! */
78	memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
79
80	if (hw_set)
81	req.arp_ha.sa_family = hw->type;
82
83	req.arp_flags = ATF_PERM;
84	args++;
85	while (*args != NULL) {
86	switch (index_in_strings(options, *args)) {
87	case 0: /* "pub" */
88	flags \|= 1;
89	args++;
90	break;
91	case 1: /* "priv" */
92	flags \|= 2;
93	args++;
94	break;
95	case 2: /* "temp" */
96	req.arp_flags &= ~ATF_PERM;
97	args++;
98	break;
99	case 3: /* "trail" */
100	req.arp_flags \|= ATF_USETRAILERS;
101	args++;
102	break;
103	case 4: /* "dontpub" */
104	#ifdef HAVE_ATF_DONTPUB
105	req.arp_flags \|= ATF_DONTPUB;
106	#else
107	bb_error_msg("feature ATF_DONTPUB is not supported");
108	#endif
109	args++;
110	break;
111	case 5: /* "auto" */
112	#ifdef HAVE_ATF_MAGIC
113	req.arp_flags \|= ATF_MAGIC;
114	#else
115	bb_error_msg("feature ATF_MAGIC is not supported");
116	#endif
117	args++;
118	break;
119	case 6: /* "dev" */
120	if (*++args == NULL)
121	bb_show_usage();
122	device = *args;
123	args++;
124	break;
125	case 7: /* "netmask" */
126	if (*++args == NULL)
127	bb_show_usage();
128	if (strcmp(*args, "255.255.255.255") != 0) {
129	host = *args;
130	if (ap->input(host, &sa) < 0) {
131	bb_herror_msg_and_die("%s", host);
132	}
133	memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
134	req.arp_flags \|= ATF_NETMASK;
135	}
136	args++;
137	break;
138	default:
139	bb_show_usage();
140	break;
141	}
142	}
143	if (flags == 0)
144	flags = 3;
145
146	strncpy(req.arp_dev, device, sizeof(req.arp_dev));
147
148	err = -1;
149
150	/* Call the kernel. */
151	if (flags & 2) {
152	if (option_mask32 & ARP_OPT_v)
153	bb_error_msg("SIOCDARP(nopub)");
154	err = ioctl(sockfd, SIOCDARP, &req);
155	if (err < 0) {
156	if (errno == ENXIO) {
157	if (flags & 1)
158	goto nopub;
159	printf("No ARP entry for %s\n", host);
160	return -1;
161	}
162	bb_perror_msg_and_die("SIOCDARP(priv)");
163	}
164	}
165	if ((flags & 1) && err) {
166	nopub:
167	req.arp_flags \|= ATF_PUBL;
168	if (option_mask32 & ARP_OPT_v)
169	bb_error_msg("SIOCDARP(pub)");
170	if (ioctl(sockfd, SIOCDARP, &req) < 0) {
171	if (errno == ENXIO) {
172	printf("No ARP entry for %s\n", host);
173	return -1;
174	}
175	bb_perror_msg_and_die("SIOCDARP(pub)");
176	}
177	}
178	return 0;
179	}
180
181	/* Get the hardware address to a specified interface name */
182	static void arp_getdevhw(char ifname, struct sockaddr sa,
183	const struct hwtype *hwt)
184	{
185	struct ifreq ifr;
186	const struct hwtype *xhw;
187
188	strcpy(ifr.ifr_name, ifname);
189	ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
190	"cant get HW-Address for '%s'", ifname);
191	if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) {
192	bb_error_msg_and_die("protocol type mismatch");
193	}
194	memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));
195
196	if (option_mask32 & ARP_OPT_v) {
197	xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
198	if (!xhw \|\| !xhw->print) {
199	xhw = get_hwntype(-1);
200	}
201	bb_error_msg("device '%s' has HW address %s '%s'",
202	ifname, xhw->name,
203	xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
204	}
205	}
206
207	/* Set an entry in the ARP cache. */
208	/* Called only from main, once */
209	static int arp_set(char **args)
210	{
211	char *host;
212	struct arpreq req;
213	struct sockaddr sa;
214	int flags;
215
216	memset(&req, 0, sizeof(req));
217
218	host = *args++;
219	if (ap->input(host, &sa) < 0) {
220	bb_herror_msg_and_die("%s", host);
221	}
222	/* If a host has more than one address, use the correct one! */
223	memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
224
225	/* Fetch the hardware address. */
226	if (*args == NULL) {
227	bb_error_msg_and_die("need hardware address");
228	}
229	if (option_mask32 & ARP_OPT_D) {
230	arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL);
231	} else {
232	if (hw->input(*args++, &req.arp_ha) < 0) {
233	bb_error_msg_and_die("invalid hardware address");
234	}
235	}
236
237	/* Check out any modifiers. */
238	flags = ATF_PERM \| ATF_COM;
239	while (*args != NULL) {
240	switch (index_in_strings(options, *args)) {
241	case 0: /* "pub" */
242	flags \|= ATF_PUBL;
243	args++;
244	break;
245	case 1: /* "priv" */
246	flags &= ~ATF_PUBL;
247	args++;
248	break;
249	case 2: /* "temp" */
250	flags &= ~ATF_PERM;
251	args++;
252	break;
253	case 3: /* "trail" */
254	flags \|= ATF_USETRAILERS;
255	args++;
256	break;
257	case 4: /* "dontpub" */
258	#ifdef HAVE_ATF_DONTPUB
259	flags \|= ATF_DONTPUB;
260	#else
261	bb_error_msg("feature ATF_DONTPUB is not supported");
262	#endif
263	args++;
264	break;
265	case 5: /* "auto" */
266	#ifdef HAVE_ATF_MAGIC
267	flags \|= ATF_MAGIC;
268	#else
269	bb_error_msg("feature ATF_MAGIC is not supported");
270	#endif
271	args++;
272	break;
273	case 6: /* "dev" */
274	if (*++args == NULL)
275	bb_show_usage();
276	device = *args;
277	args++;
278	break;
279	case 7: /* "netmask" */
280	if (*++args == NULL)
281	bb_show_usage();
282	if (strcmp(*args, "255.255.255.255") != 0) {
283	host = *args;
284	if (ap->input(host, &sa) < 0) {
285	bb_herror_msg_and_die("%s", host);
286	}
287	memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
288	flags \|= ATF_NETMASK;
289	}
290	args++;
291	break;
292	default:
293	bb_show_usage();
294	break;
295	}
296	}
297
298	/* Fill in the remainder of the request. */
299	req.arp_flags = flags;
300
301	strncpy(req.arp_dev, device, sizeof(req.arp_dev));
302
303	/* Call the kernel. */
304	if (option_mask32 & ARP_OPT_v)
305	bb_error_msg("SIOCSARP()");
306	xioctl(sockfd, SIOCSARP, &req);
307	return 0;
308	}
309
310
311	/* Print the contents of an ARP request block. */
312	static void
313	arp_disp(const char name, char ip, int type, int arp_flags,
314	char hwa, char mask, char *dev)
315	{
316	static const int arp_masks[] = {
317	ATF_PERM, ATF_PUBL,
318	#ifdef HAVE_ATF_MAGIC
319	ATF_MAGIC,
320	#endif
321	#ifdef HAVE_ATF_DONTPUB
322	ATF_DONTPUB,
323	#endif
324	ATF_USETRAILERS,
325	};
326	static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
327	#ifdef HAVE_ATF_MAGIC
328	"AUTO\0"
329	#endif
330	#ifdef HAVE_ATF_DONTPUB
331	"DONTPUB\0"
332	#endif
333	"TRAIL\0"
334	;
335
336	const struct hwtype *xhw;
337
338	xhw = get_hwntype(type);
339	if (xhw == NULL)
340	xhw = get_hwtype(DFLT_HW);
341
342	printf("%s (%s) at ", name, ip);
343
344	if (!(arp_flags & ATF_COM)) {
345	if (arp_flags & ATF_PUBL)
346	printf("* ");
347	else
348	printf("<incomplete> ");
349	} else {
350	printf("%s [%s] ", hwa, xhw->name);
351	}
352
353	if (arp_flags & ATF_NETMASK)
354	printf("netmask %s ", mask);
355
356	print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
357	printf(" on %s\n", dev);
358	}
359
360	/* Display the contents of the ARP cache in the kernel. */
361	/* Called only from main, once */
362	static int arp_show(char *name)
363	{
364	const char *host;
365	const char *hostname;
366	FILE *fp;
367	struct sockaddr sa;
368	int type, flags;
369	int num;
370	unsigned entries = 0, shown = 0;
371	char ip[128];
372	char hwa[128];
373	char mask[128];
374	char line[128];
375	char dev[128];
376
377	host = NULL;
378	if (name != NULL) {
379	/* Resolve the host name. */
380	if (ap->input(name, &sa) < 0) {
381	bb_herror_msg_and_die("%s", name);
382	}
383	host = xstrdup(ap->sprint(&sa, 1));
384	}
385	fp = xfopen_for_read("/proc/net/arp");
386	/* Bypass header -- read one line */
387	fgets(line, sizeof(line), fp);
388
389	/* Read the ARP cache entries. */
390	while (fgets(line, sizeof(line), fp)) {
391
392	mask[0] = '-'; mask[1] = '\0';
393	dev[0] = '-'; dev[1] = '\0';
394	/* All these strings can't overflow
395	* because fgets above reads limited amount of data */
396	num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
397	ip, &type, &flags, hwa, mask, dev);
398	if (num < 4)
399	break;
400
401	entries++;
402	/* if the user specified hw-type differs, skip it */
403	if (hw_set && (type != hw->type))
404	continue;
405
406	/* if the user specified address differs, skip it */
407	if (host && strcmp(ip, host) != 0)
408	continue;
409
410	/* if the user specified device differs, skip it */
411	if (device[0] && strcmp(dev, device) != 0)
412	continue;
413
414	shown++;
415	/* This IS ugly but it works -be */
416	hostname = "?";
417	if (!(option_mask32 & ARP_OPT_n)) {
418	if (ap->input(ip, &sa) < 0)
419	hostname = ip;
420	else
421	hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) \| 0x8000);
422	if (strcmp(hostname, ip) == 0)
423	hostname = "?";
424	}
425
426	arp_disp(hostname, ip, type, flags, hwa, mask, dev);
427	}
428	if (option_mask32 & ARP_OPT_v)
429	printf("Entries: %d\tSkipped: %d\tFound: %d\n",
430	entries, entries - shown, shown);
431
432	if (!shown) {
433	if (hw_set \|\| host \|\| device[0])
434	printf("No match found in %d entries\n", entries);
435	}
436	if (ENABLE_FEATURE_CLEAN_UP) {
437	free((char*)host);
438	fclose(fp);
439	}
440	return 0;
441	}
442
443	int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
444	int arp_main(int argc UNUSED_PARAM, char **argv)
445	{
446	const char *hw_type = "ether";
447	const char *protocol;
448
449	/* Initialize variables... */
450	ap = get_aftype(DFLT_AF);
451	if (!ap)
452	bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");
453
454	getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
455	&hw_type, &hw_type, &device);
456	argv += optind;
457	if (option_mask32 & ARP_OPT_A \|\| option_mask32 & ARP_OPT_p) {
458	ap = get_aftype(protocol);
459	if (ap == NULL)
460	bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
461	}
462	if (option_mask32 & ARP_OPT_A \|\| option_mask32 & ARP_OPT_p) {
463	hw = get_hwtype(hw_type);
464	if (hw == NULL)
465	bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
466	hw_set = 1;
467	}
468	//if (option_mask32 & ARP_OPT_i)... -i
469
470	if (ap->af != AF_INET) {
471	bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
472	}
473
474	/* If no hw type specified get default */
475	if (!hw) {
476	hw = get_hwtype(DFLT_HW);
477	if (!hw)
478	bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
479	}
480
481	if (hw->alen <= 0) {
482	bb_error_msg_and_die("%s: %s without ARP support",
483	hw->name, "hardware type");
484	}
485	sockfd = xsocket(AF_INET, SOCK_DGRAM, 0);
486
487	/* Now see what we have to do here... */
488	if (option_mask32 & (ARP_OPT_d\|ARP_OPT_s)) {
489	if (argv[0] == NULL)
490	bb_error_msg_and_die("need host name");
491	if (option_mask32 & ARP_OPT_s)
492	return arp_set(argv);
493	return arp_del(argv);
494	}
495	//if (option_mask32 & ARP_OPT_a) - default
496	return arp_show(argv[0]);
497	}