1/*	$OpenBSD: print-icmp.c,v 1.27 2021/12/01 18:28:46 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 */
23
24#include <sys/time.h>
25#include <sys/socket.h>
26
27#include <net/if.h>
28
29#include <netinet/in.h>
30#include <netinet/if_ether.h>
31#include <netinet/ip.h>
32#include <netinet/ip_icmp.h>
33#include <netinet/ip_var.h>
34#include <netinet/udp.h>
35#include <netinet/udp_var.h>
36#include <netinet/tcp.h>
37
38#include <stdio.h>
39#include <string.h>
40#include <limits.h>
41
42#include "interface.h"
43#include "addrtoname.h"
44#include "extract.h"			/* must come after interface.h */
45
46/* rfc1700 */
47#ifndef ICMP_UNREACH_NET_UNKNOWN
48#define ICMP_UNREACH_NET_UNKNOWN	6	/* destination net unknown */
49#endif
50#ifndef ICMP_UNREACH_HOST_UNKNOWN
51#define ICMP_UNREACH_HOST_UNKNOWN	7	/* destination host unknown */
52#endif
53#ifndef ICMP_UNREACH_ISOLATED
54#define ICMP_UNREACH_ISOLATED		8	/* source host isolated */
55#endif
56#ifndef ICMP_UNREACH_NET_PROHIB
57#define ICMP_UNREACH_NET_PROHIB		9	/* admin prohibited net */
58#endif
59#ifndef ICMP_UNREACH_HOST_PROHIB
60#define ICMP_UNREACH_HOST_PROHIB	10	/* admin prohibited host */
61#endif
62#ifndef ICMP_UNREACH_TOSNET
63#define ICMP_UNREACH_TOSNET		11	/* tos prohibited net */
64#endif
65#ifndef ICMP_UNREACH_TOSHOST
66#define ICMP_UNREACH_TOSHOST		12	/* tos prohibited host */
67#endif
68
69/* rfc1716 */
70#ifndef ICMP_UNREACH_FILTER_PROHIB
71#define ICMP_UNREACH_FILTER_PROHIB	13	/* admin prohibited filter */
72#endif
73#ifndef ICMP_UNREACH_HOST_PRECEDENCE
74#define ICMP_UNREACH_HOST_PRECEDENCE	14	/* host precedence violation */
75#endif
76#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
77#define ICMP_UNREACH_PRECEDENCE_CUTOFF	15	/* precedence cutoff */
78#endif
79
80/* rfc1256 */
81#ifndef ICMP_ROUTERADVERT
82#define ICMP_ROUTERADVERT		9	/* router advertisement */
83#endif
84#ifndef ICMP_ROUTERSOLICIT
85#define ICMP_ROUTERSOLICIT		10	/* router solicitation */
86#endif
87
88#define ICMP_INFOTYPE(type) \
89    ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
90    (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
91    (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
92    (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
93    (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
94
95/* Most of the icmp types */
96static struct tok icmp2str[] = {
97	{ ICMP_ECHOREPLY,		"echo reply" },
98	{ ICMP_SOURCEQUENCH,		"source quench" },
99	{ ICMP_ECHO,			"echo request" },
100	{ ICMP_ROUTERSOLICIT,		"router solicitation" },
101	{ ICMP_TSTAMP,			"time stamp request" },
102	{ ICMP_TSTAMPREPLY,		"time stamp reply" },
103	{ ICMP_IREQ,			"information request" },
104	{ ICMP_IREQREPLY,		"information reply" },
105	{ ICMP_MASKREQ,			"address mask request" },
106	{ 0,				NULL }
107};
108
109/* Formats for most of the ICMP_UNREACH codes */
110static struct tok unreach2str[] = {
111	{ ICMP_UNREACH_NET,		"net %s unreachable" },
112	{ ICMP_UNREACH_HOST,		"host %s unreachable" },
113	{ ICMP_UNREACH_SRCFAIL,
114	    "%s unreachable - source route failed" },
115	{ ICMP_UNREACH_NET_UNKNOWN,	"net %s unreachable - unknown" },
116	{ ICMP_UNREACH_HOST_UNKNOWN,	"host %s unreachable - unknown" },
117	{ ICMP_UNREACH_ISOLATED,
118	    "%s unreachable - source host isolated" },
119	{ ICMP_UNREACH_NET_PROHIB,
120	    "net %s unreachable - admin prohibited" },
121	{ ICMP_UNREACH_HOST_PROHIB,
122	    "host %s unreachable - admin prohibited" },
123	{ ICMP_UNREACH_TOSNET,
124	    "net %s unreachable - tos prohibited" },
125	{ ICMP_UNREACH_TOSHOST,
126	    "host %s unreachable - tos prohibited" },
127	{ ICMP_UNREACH_FILTER_PROHIB,
128	    "host %s unreachable - admin prohibited filter" },
129	{ ICMP_UNREACH_HOST_PRECEDENCE,
130	    "host %s unreachable - host precedence violation" },
131	{ ICMP_UNREACH_PRECEDENCE_CUTOFF,
132	    "host %s unreachable - precedence cutoff" },
133	{ 0,				NULL }
134};
135
136/* Formats for the ICMP_REDIRECT codes */
137static struct tok type2str[] = {
138	{ ICMP_REDIRECT_NET,		"redirect %s to net %s" },
139	{ ICMP_REDIRECT_HOST,		"redirect %s to host %s" },
140	{ ICMP_REDIRECT_TOSNET,		"redirect-tos %s to net %s" },
141	{ ICMP_REDIRECT_TOSHOST,	"redirect-tos %s to net %s" },
142	{ 0,				NULL }
143};
144
145/* rfc1191 */
146struct mtu_discovery {
147	short unused;
148	short nexthopmtu;
149};
150
151/* rfc1256 */
152struct ih_rdiscovery {
153	u_char ird_addrnum;
154	u_char ird_addrsiz;
155	u_short ird_lifetime;
156};
157
158struct id_rdiscovery {
159	u_int32_t ird_addr;
160	u_int32_t ird_pref;
161};
162
163void
164icmp_print(const u_char *bp, u_int length, const u_char *bp2)
165{
166	const struct icmp *dp;
167	const struct ip *ip;
168	const char *str, *fmt;
169	const struct ip *oip;
170	const struct udphdr *ouh;
171	u_int hlen, dport, mtu;
172	char buf[HOST_NAME_MAX+1+256];
173	char buf2[HOST_NAME_MAX+1+256];
174
175	dp = (struct icmp *)bp;
176	ip = (struct ip *)bp2;
177	str = buf;
178
179        printf("%s > %s: ",
180	    ipaddr_string(&ip->ip_src),
181	    ipaddr_string(&ip->ip_dst));
182
183	TCHECK(dp->icmp_code);
184	if (qflag)
185		(void) snprintf(buf, sizeof buf, "%u %u", dp->icmp_type,
186		    dp->icmp_code);
187	else switch (dp->icmp_type) {
188
189	case ICMP_ECHOREPLY:
190	case ICMP_ECHO:
191		if (vflag) {
192			TCHECK(dp->icmp_seq);
193			(void)snprintf(buf, sizeof buf,
194				       "echo %s (id:%04x seq:%u)",
195				       (dp->icmp_type == ICMP_ECHO)?
196				       "request": "reply",
197				       ntohs(dp->icmp_id),
198				       ntohs(dp->icmp_seq));
199		} else
200			str = tok2str(icmp2str, "type-#%u", dp->icmp_type);
201		break;
202
203	case ICMP_UNREACH:
204		TCHECK(dp->icmp_ip.ip_dst);
205		switch (dp->icmp_code) {
206
207		case ICMP_UNREACH_PROTOCOL:
208			TCHECK(dp->icmp_ip.ip_p);
209			(void)snprintf(buf, sizeof buf,
210				       "%s protocol %u unreachable",
211				       ipaddr_string(&dp->icmp_ip.ip_dst),
212				       dp->icmp_ip.ip_p);
213			break;
214
215		case ICMP_UNREACH_PORT:
216			TCHECK(dp->icmp_ip.ip_p);
217			oip = &dp->icmp_ip;
218			hlen = oip->ip_hl * 4;
219			ouh = (struct udphdr *)(((u_char *)oip) + hlen);
220			TCHECK(ouh->uh_dport);
221			dport = ntohs(ouh->uh_dport);
222			switch (oip->ip_p) {
223
224			case IPPROTO_TCP:
225				(void)snprintf(buf, sizeof buf,
226					"%s tcp port %s unreachable",
227					ipaddr_string(&oip->ip_dst),
228					tcpport_string(dport));
229				break;
230
231			case IPPROTO_UDP:
232				(void)snprintf(buf, sizeof buf,
233					"%s udp port %s unreachable",
234					ipaddr_string(&oip->ip_dst),
235					udpport_string(dport));
236				break;
237
238			default:
239				(void)snprintf(buf, sizeof buf,
240					"%s protocol %u port %u unreachable",
241					ipaddr_string(&oip->ip_dst),
242					oip->ip_p, dport);
243				break;
244			}
245			break;
246
247		case ICMP_UNREACH_NEEDFRAG:
248			{
249			const struct mtu_discovery *mp;
250
251			mp = (struct mtu_discovery *)&dp->icmp_void;
252                        mtu = EXTRACT_16BITS(&mp->nexthopmtu);
253                        if (mtu)
254			    (void)snprintf(buf, sizeof buf,
255				"%s unreachable - need to frag (mtu %u)",
256				ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
257                        else
258			    (void)snprintf(buf, sizeof buf,
259				"%s unreachable - need to frag",
260				ipaddr_string(&dp->icmp_ip.ip_dst));
261			}
262			break;
263
264		default:
265			fmt = tok2str(unreach2str, "#%u %%s unreachable",
266			    dp->icmp_code);
267			(void)snprintf(buf, sizeof buf, fmt,
268			    ipaddr_string(&dp->icmp_ip.ip_dst));
269			break;
270		}
271		break;
272
273	case ICMP_REDIRECT:
274		TCHECK(dp->icmp_ip.ip_dst);
275		fmt = tok2str(type2str, "redirect-#%u %%s to net %%s",
276		    dp->icmp_code);
277		(void)snprintf(buf, sizeof buf, fmt,
278		    ipaddr_string(&dp->icmp_ip.ip_dst),
279		    ipaddr_string(&dp->icmp_gwaddr));
280		break;
281
282	case ICMP_ROUTERADVERT:
283		{
284		const struct ih_rdiscovery *ihp;
285		const struct id_rdiscovery *idp;
286		u_int lifetime, num, size;
287
288		(void)strlcpy(buf, "router advertisement", sizeof(buf));
289
290		ihp = (struct ih_rdiscovery *)&dp->icmp_void;
291		TCHECK(*ihp);
292		(void)strlcat(buf, " lifetime ", sizeof(buf));
293		lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
294		if (lifetime < 60)
295			(void)snprintf(buf2, sizeof(buf2), "%u", lifetime);
296		else if (lifetime < 60 * 60)
297			(void)snprintf(buf2, sizeof(buf2), "%u:%02u",
298			    lifetime / 60, lifetime % 60);
299		else
300			(void)snprintf(buf2, sizeof(buf2), "%u:%02u:%02u",
301			    lifetime / 3600, (lifetime % 3600) / 60,
302			    lifetime % 60);
303		strlcat(buf, buf2, sizeof(buf));
304
305		num = ihp->ird_addrnum;
306		(void)snprintf(buf2, sizeof(buf2), " %u:", num);
307		strlcat(buf, buf2, sizeof(buf));
308
309		size = ihp->ird_addrsiz;
310		if (size != 2) {
311			(void)snprintf(buf2, sizeof(buf2), " [size %u]", size);
312			strlcat(buf, buf2, sizeof(buf));
313			break;
314		}
315		idp = (struct id_rdiscovery *)&dp->icmp_data;
316		while (num-- > 0) {
317			TCHECK(*idp);
318			(void)snprintf(buf2, sizeof(buf2), " {%s %u}",
319			    ipaddr_string(&idp->ird_addr),
320			    EXTRACT_32BITS(&idp->ird_pref));
321			strlcat(buf, buf2, sizeof(buf));
322		}
323		}
324		break;
325
326	case ICMP_TIMXCEED:
327		TCHECK(dp->icmp_ip.ip_dst);
328		switch (dp->icmp_code) {
329
330		case ICMP_TIMXCEED_INTRANS:
331			str = "time exceeded in-transit";
332			break;
333
334		case ICMP_TIMXCEED_REASS:
335			str = "ip reassembly time exceeded";
336			break;
337
338		default:
339			(void)snprintf(buf, sizeof buf,
340				"time exceeded-#%u", dp->icmp_code);
341			break;
342		}
343		break;
344
345	case ICMP_PARAMPROB:
346		switch (dp->icmp_code) {
347		case ICMP_PARAMPROB_OPTABSENT:
348			str = "requested option absent";
349			break;
350		case ICMP_PARAMPROB_LENGTH:
351			snprintf(buf, sizeof buf, "bad length %u", dp->icmp_pptr);
352			break;
353		default:
354			TCHECK(dp->icmp_pptr);
355			(void)snprintf(buf, sizeof buf,
356				"parameter problem - octet %u",
357				dp->icmp_pptr);
358			break;
359		}
360		break;
361
362	case ICMP_MASKREPLY:
363		TCHECK(dp->icmp_mask);
364		(void)snprintf(buf, sizeof buf, "address mask is 0x%08x",
365		    (u_int32_t)ntohl(dp->icmp_mask));
366		break;
367
368	default:
369		str = tok2str(icmp2str, "type-#%u", dp->icmp_type);
370		break;
371	}
372	printf("icmp: %s", str);
373	if (vflag) {
374		if (TTEST2(dp->icmp_type, length)) {
375			u_int16_t sum, icmp_sum;
376			sum = in_cksum((const u_short *)dp, length, 0);
377			if (sum != 0) {
378				icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
379				printf(" [bad icmp cksum %x! -> %x]", icmp_sum,
380				    in_cksum_shouldbe(icmp_sum, sum));
381			}
382			else
383				printf(" [icmp cksum ok]");
384		}
385	}
386	if (vflag > 1 && !ICMP_INFOTYPE(dp->icmp_type) &&
387	    TTEST(dp->icmp_ip)) {
388		printf(" for ");
389		oip = &dp->icmp_ip;
390		ip_print((u_char *)oip, ntohs(oip->ip_len));
391	}
392	return;
393trunc:
394	printf("[|icmp]");
395}
396