xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.sbin/snoop/snoop_arp.c (revision 71269a2275bf5a143dad6461eee2710a344e7261)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <sys/types.h>
29 #include <sys/errno.h>
30 #include <setjmp.h>
31 #include <sys/socket.h>
32 #include <net/if.h>
33 #include <net/if_arp.h>
34 #include <netinet/in_systm.h>
35 #include <netinet/in.h>
36 #include <netinet/ip.h>
37 #include <netinet/if_ether.h>
38 #include <netdb.h>
39 #include <net/if_types.h>
40 
41 #include "snoop.h"
42 
43 extern char *dlc_header;
44 extern jmp_buf xdr_err;
45 
46 static char *printip(unsigned char *);
47 static char *addrtoname_align(unsigned char *);
48 
49 static char unarp_addr[] = "Unknown";
50 char *opname[] = {
51 	"",
52 	"ARP Request",
53 	"ARP Reply",
54 	"REVARP Request",
55 	"REVARP Reply",
56 };
57 
58 void
59 interpret_arp(int flags, struct arphdr *ap, int alen)
60 {
61 	char *line;
62 	extern char *src_name, *dst_name;
63 	unsigned char *sip, *tip, *sha, *tha;
64 	char *smacbuf = NULL, *dmacbuf = NULL;
65 	int maclen;
66 	ushort_t arpop;
67 	boolean_t is_ip = B_FALSE;
68 
69 	/*
70 	 * Check that at least the generic ARP header was received.
71 	 */
72 	if (sizeof (struct arphdr) > alen)
73 		goto short_packet;
74 
75 	arpop = ntohs(ap->ar_op);
76 	maclen = ap->ar_hln;
77 	if (ntohs(ap->ar_pro) == ETHERTYPE_IP)
78 		is_ip = B_TRUE;
79 
80 	sha = (unsigned char *)(ap + 1);
81 	sip = sha + maclen;
82 	tha = sip + ap->ar_pln;
83 	tip = tha + maclen;
84 
85 	/*
86 	 * Check that the protocol/hardware addresses were received.
87 	 */
88 	if ((tip + ap->ar_pln) > ((unsigned char *)ap + alen))
89 		goto short_packet;
90 
91 	if (maclen == 0) {
92 		smacbuf = dmacbuf = unarp_addr;
93 	} else {
94 		if (((flags & F_DTAIL) && is_ip) || (arpop == ARPOP_REPLY)) {
95 			smacbuf = _link_ntoa(sha, NULL, maclen, IFT_OTHER);
96 			if (smacbuf == NULL)
97 				pr_err("Warning: malloc failure");
98 		}
99 
100 		if (((flags & F_DTAIL) && is_ip) || (arpop ==
101 		    REVARP_REQUEST) || (arpop == REVARP_REPLY)) {
102 			dmacbuf = _link_ntoa(tha, NULL, maclen, IFT_OTHER);
103 			if (dmacbuf == NULL)
104 				pr_err("Warning: malloc failure");
105 		}
106 	}
107 
108 	src_name = addrtoname_align(sip);
109 
110 	if (flags & F_SUM) {
111 
112 		line = get_sum_line();
113 
114 		switch (arpop) {
115 		case ARPOP_REQUEST:
116 			(void) snprintf(line, MAXLINE, "ARP C Who is %s ?",
117 			    printip(tip));
118 			break;
119 		case ARPOP_REPLY:
120 			(void) snprintf(line, MAXLINE, "ARP R %s is %s",
121 			    printip(sip), smacbuf);
122 			dst_name = addrtoname_align(tip);
123 			break;
124 		case REVARP_REQUEST:
125 			(void) snprintf(line, MAXLINE, "RARP C Who is %s ?",
126 			    dmacbuf);
127 			break;
128 		case REVARP_REPLY:
129 			(void) snprintf(line, MAXLINE, "RARP R %s is %s",
130 			    dmacbuf, printip(tip));
131 			dst_name = addrtoname_align(tip);
132 			break;
133 		}
134 	}
135 
136 	if (flags & F_DTAIL) {
137 		show_header("ARP:  ", "ARP/RARP Frame", alen);
138 		show_space();
139 		(void) snprintf(get_line(0, 0), get_line_remain(),
140 		    "Hardware type = %d (%s)", ntohs(ap->ar_hrd),
141 		    arp_htype(ntohs(ap->ar_hrd)));
142 		(void) snprintf(get_line(0, 0), get_line_remain(),
143 		    "Protocol type = %04x (%s)", ntohs(ap->ar_pro),
144 		    print_ethertype(ntohs(ap->ar_pro)));
145 		(void) snprintf(get_line(0, 0), get_line_remain(),
146 		    "Length of hardware address = %d bytes", ap->ar_hln);
147 		(void) snprintf(get_line(0, 0), get_line_remain(),
148 		    "Length of protocol address = %d bytes", ap->ar_pln);
149 		(void) snprintf(get_line(0, 0), get_line_remain(),
150 		    "Opcode %d (%s)", arpop,
151 		    (arpop > REVARP_REPLY) ? opname[0] : opname[arpop]);
152 
153 		if (is_ip) {
154 			(void) snprintf(get_line(0, 0), get_line_remain(),
155 			    "Sender's hardware address = %s", smacbuf);
156 			(void) snprintf(get_line(0, 0), get_line_remain(),
157 			    "Sender's protocol address = %s",
158 			    printip(sip));
159 			(void) snprintf(get_line(0, 0), get_line_remain(),
160 			    "Target hardware address = %s",
161 			    arpop == ARPOP_REQUEST ? "?" : dmacbuf);
162 			(void) snprintf(get_line(0, 0), get_line_remain(),
163 			    "Target protocol address = %s",
164 			    arpop == REVARP_REQUEST ? "?" :
165 			    printip(tip));
166 		}
167 		show_trailer();
168 	}
169 
170 	if (maclen != 0) {
171 		free(smacbuf);
172 		free(dmacbuf);
173 	}
174 	return;
175 
176 short_packet:
177 	if (flags & F_SUM) {
178 		(void) snprintf(get_sum_line(), MAXLINE,
179 		    "ARP (short packet)");
180 	} else if (flags & F_DTAIL) {
181 		show_header("ARP:  ", "ARP/RARP Frame", alen);
182 		show_space();
183 		(void) snprintf(get_line(0, 0), get_line_remain(),
184 		    "ARP (short packet)");
185 	}
186 }
187 
188 char *
189 printip(unsigned char *p)
190 {
191 	static char buff[MAXHOSTNAMELEN + 32];
192 	char *ap, *np;
193 	struct in_addr a;
194 
195 	memcpy(&a, p, 4);
196 	ap = (char *)inet_ntoa(a);
197 	np = (char *)addrtoname(AF_INET, &a);
198 	(void) snprintf(buff, MAXHOSTNAMELEN, "%s, %s", ap, np);
199 	return (buff);
200 }
201 
202 char *
203 addrtoname_align(unsigned char *p)
204 {
205 	struct in_addr a;
206 
207 	memcpy(&a, p, 4);
208 	return ((char *)addrtoname(AF_INET, &a));
209 }
210 
211 /*
212  * These numbers are assigned by the IANA.  See the arp-parameters registry.
213  * Only those values that are used within Solaris have #defines.
214  */
215 const char *
216 arp_htype(int t)
217 {
218 	switch (t) {
219 	case ARPHRD_ETHER:
220 		return ("Ethernet (10Mb)");
221 	case 2:
222 		return ("Experimental Ethernet (3MB)");
223 	case 3:
224 		return ("Amateur Radio AX.25");
225 	case 4:
226 		return ("Proteon ProNET Token Ring");
227 	case 5:
228 		return ("Chaos");
229 	case ARPHRD_IEEE802:
230 		return ("IEEE 802");
231 	case 7:
232 		return ("ARCNET");
233 	case 8:
234 		return ("Hyperchannel");
235 	case 9:
236 		return ("Lanstar");
237 	case 10:
238 		return ("Autonet");
239 	case 11:
240 		return ("LocalTalk");
241 	case 12:
242 		return ("LocalNet");
243 	case 13:
244 		return ("Ultra Link");
245 	case 14:
246 		return ("SMDS");
247 	case ARPHRD_FRAME:
248 		return ("Frame Relay");
249 	case ARPHRD_ATM:
250 		return ("ATM");
251 	case ARPHRD_HDLC:
252 		return ("HDLC");
253 	case ARPHRD_FC:
254 		return ("Fibre Channel");
255 	case ARPHRD_IPATM:
256 		return ("IP-ATM");
257 	case ARPHRD_TUNNEL:
258 		return ("Tunnel");
259 	case ARPHRD_IB:
260 		return ("IPIB");
261 	};
262 	return ("UNKNOWN");
263 }
264