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"

enum {
	ARP_OPT_A = (1 << 0),
	ARP_OPT_p = (1 << 1),
	ARP_OPT_H = (1 << 2),
	ARP_OPT_t = (1 << 3),
	ARP_OPT_i = (1 << 4),
	ARP_OPT_a = (1 << 5),
	ARP_OPT_d = (1 << 6),
	ARP_OPT_n = (1 << 7), /* do not resolve addresses */
	ARP_OPT_D = (1 << 8), /* HW-address is devicename */
	ARP_OPT_s = (1 << 9),
	ARP_OPT_v = (1 << 10) * DEBUG, /* debugging output flag */
};

enum {
	sockfd = 3, /* active socket descriptor */
};

struct globals {
	const struct aftype *ap; /* current address family */
	const struct hwtype *hw; /* current hardware type */
	const char *device;      /* current device */
	smallint hw_set;         /* flag if hw-type was set (-H) */

} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define ap         (G.ap        )
#define hw         (G.hw        )
#define device     (G.device    )
#define hw_set     (G.hw_set    )
#define INIT_G() do { \
	device = ""; \
} while (0)


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;
	unsigned opts;

	INIT_G();

	xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sockfd);
	ap = get_aftype(DFLT_AF);
	if (!ap)
		bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");

	opts = getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
				 &hw_type, &hw_type, &device);
	argv += optind;
	if (opts & (ARP_OPT_A | ARP_OPT_p)) {
		ap = get_aftype(protocol);
		if (ap == NULL)
			bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
	}
	if (opts & (ARP_OPT_A | 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 (opts & 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");
	}

	/* Now see what we have to do here... */
	if (opts & (ARP_OPT_d | ARP_OPT_s)) {
		if (argv[0] == NULL)
			bb_error_msg_and_die("need host name");
		if (opts & ARP_OPT_s)
			return arp_set(argv);
		return arp_del(argv);
	}
	//if (opts & ARP_OPT_a) - default
	return arp_show(argv[0]);
}
1	niro	532	/* 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	niro	816	#include "libbb.h"
17	niro	532	#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	niro	984	enum {
31			ARP_OPT_A = (1 << 0),
32			ARP_OPT_p = (1 << 1),
33			ARP_OPT_H = (1 << 2),
34			ARP_OPT_t = (1 << 3),
35			ARP_OPT_i = (1 << 4),
36			ARP_OPT_a = (1 << 5),
37			ARP_OPT_d = (1 << 6),
38			ARP_OPT_n = (1 << 7), /* do not resolve addresses */
39			ARP_OPT_D = (1 << 8), /* HW-address is devicename */
40			ARP_OPT_s = (1 << 9),
41			ARP_OPT_v = (1 << 10) * DEBUG, /* debugging output flag */
42			};
43	niro	532
44	niro	984	enum {
45			sockfd = 3, /* active socket descriptor */
46			};
47	niro	532
48	niro	984	struct globals {
49			const struct aftype ap; / current address family */
50			const struct hwtype hw; / current hardware type */
51			const char device; / current device */
52			smallint hw_set; /* flag if hw-type was set (-H) */
53	niro	532
54	niro	1123	} FIX_ALIASING;
55	niro	984	#define G ((struct globals)&bb_common_bufsiz1)
56			#define ap (G.ap )
57			#define hw (G.hw )
58			#define device (G.device )
59			#define hw_set (G.hw_set )
60			#define INIT_G() do { \
61			device = ""; \
62			} while (0)
63
64
65	niro	816	static const char options[] ALIGN1 =
66			"pub\0"
67			"priv\0"
68			"temp\0"
69			"trail\0"
70			"dontpub\0"
71			"auto\0"
72			"dev\0"
73			"netmask\0";
74	niro	532
75			/* Delete an entry from the ARP cache. */
76			/* Called only from main, once */
77			static int arp_del(char **args)
78			{
79	niro	816	char *host;
80	niro	532	struct arpreq req;
81			struct sockaddr sa;
82			int flags = 0;
83			int err;
84
85			memset(&req, 0, sizeof(req));
86
87			/* Resolve the host name. */
88	niro	816	host = *args;
89			if (ap->input(host, &sa) < 0) {
90	niro	532	bb_herror_msg_and_die("%s", host);
91			}
92
93			/* If a host has more than one address, use the correct one! */
94			memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
95
96			if (hw_set)
97			req.arp_ha.sa_family = hw->type;
98
99			req.arp_flags = ATF_PERM;
100			args++;
101			while (*args != NULL) {
102	niro	816	switch (index_in_strings(options, *args)) {
103	niro	532	case 0: /* "pub" */
104			flags \|= 1;
105			args++;
106			break;
107			case 1: /* "priv" */
108			flags \|= 2;
109			args++;
110			break;
111			case 2: /* "temp" */
112			req.arp_flags &= ~ATF_PERM;
113			args++;
114			break;
115			case 3: /* "trail" */
116			req.arp_flags \|= ATF_USETRAILERS;
117			args++;
118			break;
119			case 4: /* "dontpub" */
120			#ifdef HAVE_ATF_DONTPUB
121			req.arp_flags \|= ATF_DONTPUB;
122			#else
123			bb_error_msg("feature ATF_DONTPUB is not supported");
124			#endif
125			args++;
126			break;
127			case 5: /* "auto" */
128			#ifdef HAVE_ATF_MAGIC
129			req.arp_flags \|= ATF_MAGIC;
130			#else
131			bb_error_msg("feature ATF_MAGIC is not supported");
132			#endif
133			args++;
134			break;
135			case 6: /* "dev" */
136			if (*++args == NULL)
137			bb_show_usage();
138			device = *args;
139			args++;
140			break;
141			case 7: /* "netmask" */
142			if (*++args == NULL)
143			bb_show_usage();
144			if (strcmp(*args, "255.255.255.255") != 0) {
145	niro	816	host = *args;
146			if (ap->input(host, &sa) < 0) {
147	niro	532	bb_herror_msg_and_die("%s", host);
148			}
149			memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
150			req.arp_flags \|= ATF_NETMASK;
151			}
152			args++;
153			break;
154			default:
155			bb_show_usage();
156			break;
157			}
158			}
159			if (flags == 0)
160			flags = 3;
161
162			strncpy(req.arp_dev, device, sizeof(req.arp_dev));
163
164			err = -1;
165
166			/* Call the kernel. */
167			if (flags & 2) {
168			if (option_mask32 & ARP_OPT_v)
169			bb_error_msg("SIOCDARP(nopub)");
170			err = ioctl(sockfd, SIOCDARP, &req);
171			if (err < 0) {
172			if (errno == ENXIO) {
173			if (flags & 1)
174			goto nopub;
175			printf("No ARP entry for %s\n", host);
176			return -1;
177			}
178			bb_perror_msg_and_die("SIOCDARP(priv)");
179			}
180			}
181			if ((flags & 1) && err) {
182			nopub:
183			req.arp_flags \|= ATF_PUBL;
184			if (option_mask32 & ARP_OPT_v)
185			bb_error_msg("SIOCDARP(pub)");
186			if (ioctl(sockfd, SIOCDARP, &req) < 0) {
187			if (errno == ENXIO) {
188			printf("No ARP entry for %s\n", host);
189			return -1;
190			}
191			bb_perror_msg_and_die("SIOCDARP(pub)");
192			}
193			}
194			return 0;
195			}
196
197			/* Get the hardware address to a specified interface name */
198			static void arp_getdevhw(char ifname, struct sockaddr sa,
199			const struct hwtype *hwt)
200			{
201			struct ifreq ifr;
202			const struct hwtype *xhw;
203
204			strcpy(ifr.ifr_name, ifname);
205	niro	816	ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
206			"cant get HW-Address for '%s'", ifname);
207	niro	532	if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) {
208			bb_error_msg_and_die("protocol type mismatch");
209			}
210			memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));
211
212			if (option_mask32 & ARP_OPT_v) {
213			xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
214			if (!xhw \|\| !xhw->print) {
215			xhw = get_hwntype(-1);
216			}
217			bb_error_msg("device '%s' has HW address %s '%s'",
218			ifname, xhw->name,
219	niro	816	xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
220	niro	532	}
221			}
222
223			/* Set an entry in the ARP cache. */
224			/* Called only from main, once */
225			static int arp_set(char **args)
226			{
227	niro	816	char *host;
228	niro	532	struct arpreq req;
229			struct sockaddr sa;
230			int flags;
231
232			memset(&req, 0, sizeof(req));
233
234	niro	816	host = *args++;
235			if (ap->input(host, &sa) < 0) {
236	niro	532	bb_herror_msg_and_die("%s", host);
237			}
238			/* If a host has more than one address, use the correct one! */
239			memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
240
241			/* Fetch the hardware address. */
242			if (*args == NULL) {
243			bb_error_msg_and_die("need hardware address");
244			}
245			if (option_mask32 & ARP_OPT_D) {
246			arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL);
247			} else {
248			if (hw->input(*args++, &req.arp_ha) < 0) {
249			bb_error_msg_and_die("invalid hardware address");
250			}
251			}
252
253			/* Check out any modifiers. */
254			flags = ATF_PERM \| ATF_COM;
255			while (*args != NULL) {
256	niro	816	switch (index_in_strings(options, *args)) {
257	niro	532	case 0: /* "pub" */
258			flags \|= ATF_PUBL;
259			args++;
260			break;
261			case 1: /* "priv" */
262			flags &= ~ATF_PUBL;
263			args++;
264			break;
265			case 2: /* "temp" */
266			flags &= ~ATF_PERM;
267			args++;
268			break;
269			case 3: /* "trail" */
270			flags \|= ATF_USETRAILERS;
271			args++;
272			break;
273			case 4: /* "dontpub" */
274			#ifdef HAVE_ATF_DONTPUB
275			flags \|= ATF_DONTPUB;
276			#else
277			bb_error_msg("feature ATF_DONTPUB is not supported");
278			#endif
279			args++;
280			break;
281			case 5: /* "auto" */
282			#ifdef HAVE_ATF_MAGIC
283			flags \|= ATF_MAGIC;
284			#else
285			bb_error_msg("feature ATF_MAGIC is not supported");
286			#endif
287			args++;
288			break;
289			case 6: /* "dev" */
290			if (*++args == NULL)
291			bb_show_usage();
292			device = *args;
293			args++;
294			break;
295			case 7: /* "netmask" */
296			if (*++args == NULL)
297			bb_show_usage();
298			if (strcmp(*args, "255.255.255.255") != 0) {
299	niro	816	host = *args;
300			if (ap->input(host, &sa) < 0) {
301	niro	532	bb_herror_msg_and_die("%s", host);
302			}
303			memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
304			flags \|= ATF_NETMASK;
305			}
306			args++;
307			break;
308			default:
309			bb_show_usage();
310			break;
311			}
312			}
313
314			/* Fill in the remainder of the request. */
315			req.arp_flags = flags;
316
317			strncpy(req.arp_dev, device, sizeof(req.arp_dev));
318
319			/* Call the kernel. */
320			if (option_mask32 & ARP_OPT_v)
321			bb_error_msg("SIOCSARP()");
322	niro	816	xioctl(sockfd, SIOCSARP, &req);
323	niro	532	return 0;
324			}
325
326
327			/* Print the contents of an ARP request block. */
328			static void
329	niro	816	arp_disp(const char name, char ip, int type, int arp_flags,
330	niro	532	char hwa, char mask, char *dev)
331			{
332	niro	816	static const int arp_masks[] = {
333			ATF_PERM, ATF_PUBL,
334			#ifdef HAVE_ATF_MAGIC
335			ATF_MAGIC,
336			#endif
337			#ifdef HAVE_ATF_DONTPUB
338			ATF_DONTPUB,
339			#endif
340			ATF_USETRAILERS,
341			};
342			static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
343			#ifdef HAVE_ATF_MAGIC
344			"AUTO\0"
345			#endif
346			#ifdef HAVE_ATF_DONTPUB
347			"DONTPUB\0"
348			#endif
349			"TRAIL\0"
350			;
351
352	niro	532	const struct hwtype *xhw;
353
354			xhw = get_hwntype(type);
355			if (xhw == NULL)
356			xhw = get_hwtype(DFLT_HW);
357
358			printf("%s (%s) at ", name, ip);
359
360			if (!(arp_flags & ATF_COM)) {
361			if (arp_flags & ATF_PUBL)
362			printf("* ");
363			else
364			printf("<incomplete> ");
365			} else {
366			printf("%s [%s] ", hwa, xhw->name);
367			}
368
369			if (arp_flags & ATF_NETMASK)
370			printf("netmask %s ", mask);
371
372	niro	816	print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
373			printf(" on %s\n", dev);
374	niro	532	}
375
376			/* Display the contents of the ARP cache in the kernel. */
377			/* Called only from main, once */
378			static int arp_show(char *name)
379			{
380	niro	816	const char *host;
381			const char *hostname;
382			FILE *fp;
383	niro	532	struct sockaddr sa;
384			int type, flags;
385			int num;
386			unsigned entries = 0, shown = 0;
387	niro	816	char ip[128];
388			char hwa[128];
389			char mask[128];
390			char line[128];
391			char dev[128];
392	niro	532
393	niro	816	host = NULL;
394	niro	532	if (name != NULL) {
395			/* Resolve the host name. */
396	niro	816	if (ap->input(name, &sa) < 0) {
397			bb_herror_msg_and_die("%s", name);
398	niro	532	}
399	niro	816	host = xstrdup(ap->sprint(&sa, 1));
400	niro	532	}
401	niro	816	fp = xfopen_for_read("/proc/net/arp");
402			/* Bypass header -- read one line */
403			fgets(line, sizeof(line), fp);
404
405			/* Read the ARP cache entries. */
406			while (fgets(line, sizeof(line), fp)) {
407
408	niro	532	mask[0] = '-'; mask[1] = '\0';
409			dev[0] = '-'; dev[1] = '\0';
410	niro	816	/* All these strings can't overflow
411			* because fgets above reads limited amount of data */
412			num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
413			ip, &type, &flags, hwa, mask, dev);
414			if (num < 4)
415			break;
416	niro	532
417	niro	816	entries++;
418			/* if the user specified hw-type differs, skip it */
419			if (hw_set && (type != hw->type))
420			continue;
421	niro	532
422	niro	816	/* if the user specified address differs, skip it */
423			if (host && strcmp(ip, host) != 0)
424			continue;
425	niro	532
426	niro	816	/* if the user specified device differs, skip it */
427			if (device[0] && strcmp(dev, device) != 0)
428			continue;
429	niro	532
430	niro	816	shown++;
431			/* This IS ugly but it works -be */
432			hostname = "?";
433			if (!(option_mask32 & ARP_OPT_n)) {
434			if (ap->input(ip, &sa) < 0)
435			hostname = ip;
436			else
437			hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) \| 0x8000);
438			if (strcmp(hostname, ip) == 0)
439	niro	532	hostname = "?";
440	niro	816	}
441	niro	532
442	niro	816	arp_disp(hostname, ip, type, flags, hwa, mask, dev);
443	niro	532	}
444			if (option_mask32 & ARP_OPT_v)
445			printf("Entries: %d\tSkipped: %d\tFound: %d\n",
446			entries, entries - shown, shown);
447
448			if (!shown) {
449	niro	816	if (hw_set \|\| host \|\| device[0])
450	niro	532	printf("No match found in %d entries\n", entries);
451			}
452	niro	816	if (ENABLE_FEATURE_CLEAN_UP) {
453			free((char*)host);
454			fclose(fp);
455			}
456	niro	532	return 0;
457			}
458
459	niro	816	int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
460			int arp_main(int argc UNUSED_PARAM, char **argv)
461	niro	532	{
462	niro	816	const char *hw_type = "ether";
463			const char *protocol;
464	niro	984	unsigned opts;
465	niro	532
466	niro	984	INIT_G();
467
468			xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sockfd);
469	niro	532	ap = get_aftype(DFLT_AF);
470			if (!ap)
471			bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");
472
473	niro	984	opts = getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
474	niro	532	&hw_type, &hw_type, &device);
475			argv += optind;
476	niro	984	if (opts & (ARP_OPT_A \| ARP_OPT_p)) {
477	niro	532	ap = get_aftype(protocol);
478			if (ap == NULL)
479			bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
480			}
481	niro	984	if (opts & (ARP_OPT_A \| ARP_OPT_p)) {
482	niro	532	hw = get_hwtype(hw_type);
483			if (hw == NULL)
484			bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
485			hw_set = 1;
486			}
487	niro	984	//if (opts & ARP_OPT_i)... -i
488	niro	532
489			if (ap->af != AF_INET) {
490			bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
491			}
492
493			/* If no hw type specified get default */
494			if (!hw) {
495			hw = get_hwtype(DFLT_HW);
496			if (!hw)
497			bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
498			}
499
500			if (hw->alen <= 0) {
501			bb_error_msg_and_die("%s: %s without ARP support",
502			hw->name, "hardware type");
503			}
504
505			/* Now see what we have to do here... */
506	niro	984	if (opts & (ARP_OPT_d \| ARP_OPT_s)) {
507	niro	532	if (argv[0] == NULL)
508			bb_error_msg_and_die("need host name");
509	niro	984	if (opts & ARP_OPT_s)
510	niro	532	return arp_set(argv);
511			return arp_del(argv);
512			}
513	niro	984	//if (opts & ARP_OPT_a) - default
514	niro	532	return arp_show(argv[0]);
515			}