1 /* $NetBSD: icmp.c,v 1.3 2022/04/03 01:10:58 christos Exp $ */
2
3 /* dhcp.c
4
5 ICMP Protocol engine - for sending out pings and receiving
6 responses. */
7
8 /*
9 * Copyright (C) 2004-2022 Internet Systems Consortium, Inc. ("ISC")
10 * Copyright (c) 1996-2003 by Internet Software Consortium
11 *
12 * This Source Code Form is subject to the terms of the Mozilla Public
13 * License, v. 2.0. If a copy of the MPL was not distributed with this
14 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
17 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
19 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
20 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
21 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
22 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
23 *
24 * Internet Systems Consortium, Inc.
25 * PO Box 360
26 * Newmarket, NH 03857 USA
27 * <info@isc.org>
28 * https://www.isc.org/
29 *
30 */
31
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: icmp.c,v 1.3 2022/04/03 01:10:58 christos Exp $");
34
35 #include "dhcpd.h"
36 #include "netinet/ip.h"
37 #include "netinet/ip_icmp.h"
38
39 struct icmp_state *icmp_state;
40 static omapi_object_type_t *dhcp_type_icmp;
41 static int no_icmp;
42
43 OMAPI_OBJECT_ALLOC (icmp_state, struct icmp_state, dhcp_type_icmp)
44
45 #if defined (TRACING)
46 trace_type_t *trace_icmp_input;
47 trace_type_t *trace_icmp_output;
48 #endif
49
50 /* Initialize the ICMP protocol. */
51
icmp_startup(routep,handler)52 void icmp_startup (routep, handler)
53 int routep;
54 void (*handler) (struct iaddr, u_int8_t *, int);
55 {
56 struct protoent *proto;
57 int protocol = 1;
58 int state;
59 isc_result_t result;
60
61 /* Only initialize icmp once. */
62 if (dhcp_type_icmp)
63 log_fatal ("attempted to reinitialize icmp protocol");
64
65 result = omapi_object_type_register (&dhcp_type_icmp, "icmp",
66 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
67 sizeof (struct icmp_state),
68 0, RC_MISC);
69
70 if (result != ISC_R_SUCCESS)
71 log_fatal ("Can't register icmp object type: %s",
72 isc_result_totext (result));
73
74 icmp_state_allocate (&icmp_state, MDL);
75 icmp_state -> icmp_handler = handler;
76
77 #if defined (TRACING)
78 trace_icmp_input = trace_type_register ("icmp-input", (void *)0,
79 trace_icmp_input_input,
80 trace_icmp_input_stop, MDL);
81 trace_icmp_output = trace_type_register ("icmp-output", (void *)0,
82 trace_icmp_output_input,
83 trace_icmp_output_stop, MDL);
84
85 /* If we're playing back a trace file, don't create the socket
86 or set up the callback. */
87 if (!trace_playback ()) {
88 #endif
89 /* Get the protocol number (should be 1). */
90 proto = getprotobyname ("icmp");
91 if (proto)
92 protocol = proto -> p_proto;
93
94 /* Get a raw socket for the ICMP protocol. */
95 icmp_state -> socket = socket (AF_INET, SOCK_RAW, protocol);
96 if (icmp_state -> socket < 0) {
97 no_icmp = 1;
98 log_error ("unable to create icmp socket: %m");
99 return;
100 }
101
102 #if defined (HAVE_SETFD)
103 if (fcntl (icmp_state -> socket, F_SETFD, 1) < 0)
104 log_error ("Can't set close-on-exec on icmp: %m");
105 #endif
106
107 /* Make sure it does routing... */
108 state = 0;
109 if (setsockopt (icmp_state -> socket, SOL_SOCKET, SO_DONTROUTE,
110 (char *)&state, sizeof state) < 0)
111 log_fatal ("Can't disable SO_DONTROUTE on ICMP: %m");
112
113 result = (omapi_register_io_object
114 ((omapi_object_t *)icmp_state,
115 icmp_readsocket, 0, icmp_echoreply, 0, 0));
116 if (result != ISC_R_SUCCESS)
117 log_fatal ("Can't register icmp handle: %s",
118 isc_result_totext (result));
119 #if defined (TRACING)
120 }
121 #endif
122 }
123
icmp_readsocket(h)124 int icmp_readsocket (h)
125 omapi_object_t *h;
126 {
127 struct icmp_state *state;
128
129 state = (struct icmp_state *)h;
130 return state -> socket;
131 }
132
icmp_echorequest(addr)133 int icmp_echorequest (addr)
134 struct iaddr *addr;
135 {
136 struct sockaddr_in to;
137 struct icmp icmp;
138 int status;
139 #if defined (TRACING)
140 trace_iov_t iov [2];
141 #endif
142
143 if (no_icmp)
144 return 1;
145 if (!icmp_state)
146 log_fatal ("ICMP protocol used before initialization.");
147
148 memset (&to, 0, sizeof(to));
149 #ifdef HAVE_SA_LEN
150 to.sin_len = sizeof to;
151 #endif
152 to.sin_family = AF_INET;
153 to.sin_port = 0; /* unused. */
154 memcpy (&to.sin_addr, addr -> iabuf, sizeof to.sin_addr); /* XXX */
155
156 icmp.icmp_type = ICMP_ECHO;
157 icmp.icmp_code = 0;
158 icmp.icmp_cksum = 0;
159 icmp.icmp_seq = 0;
160 #ifdef _LP64
161 icmp.icmp_id = (((u_int32_t)(u_int64_t)addr) ^
162 (u_int32_t)(((u_int64_t)addr) >> 32));
163 #else
164 icmp.icmp_id = (u_int32_t)addr;
165 #endif
166 memset (&icmp.icmp_dun, 0, sizeof icmp.icmp_dun);
167
168 icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
169 sizeof icmp, 0));
170
171 #if defined (TRACING)
172 if (trace_playback ()) {
173 char *buf = (char *)0;
174 unsigned buflen = 0;
175
176 /* Consume the ICMP event. */
177 status = trace_get_packet (&trace_icmp_output, &buflen, &buf);
178 if (status != ISC_R_SUCCESS)
179 log_error ("icmp_echorequest: %s",
180 isc_result_totext (status));
181 if (buf)
182 dfree (buf, MDL);
183 } else {
184 if (trace_record ()) {
185 iov [0].buf = (char *)addr;
186 iov [0].len = sizeof *addr;
187 iov [1].buf = (char *)&icmp;
188 iov [1].len = sizeof icmp;
189 trace_write_packet_iov (trace_icmp_output,
190 2, iov, MDL);
191 }
192 #endif
193 /* Send the ICMP packet... */
194 status = sendto (icmp_state -> socket,
195 (char *)&icmp, sizeof icmp, 0,
196 (struct sockaddr *)&to, sizeof to);
197 if (status < 0)
198 log_error ("icmp_echorequest %s: %m",
199 inet_ntoa(to.sin_addr));
200
201 if (status != sizeof icmp)
202 return 0;
203 #if defined (TRACING)
204 }
205 #endif
206 return 1;
207 }
208
icmp_echoreply(h)209 isc_result_t icmp_echoreply (h)
210 omapi_object_t *h;
211 {
212 struct icmp *icfrom;
213 struct ip *ip;
214 struct sockaddr_in from;
215 u_int8_t icbuf [1500];
216 int status;
217 SOCKLEN_T sl;
218 int hlen, len;
219 struct iaddr ia;
220 struct icmp_state *state;
221 #if defined (TRACING)
222 trace_iov_t iov [2];
223 #endif
224
225 state = (struct icmp_state *)h;
226
227 sl = sizeof from;
228 status = recvfrom (state -> socket, (char *)icbuf, sizeof icbuf, 0,
229 (struct sockaddr *)&from, &sl);
230 if (status < 0) {
231 log_error ("icmp_echoreply: %m");
232 return ISC_R_UNEXPECTED;
233 }
234
235 /* Find the IP header length... */
236 ip = (struct ip *)icbuf;
237 hlen = IP_HL (ip);
238
239 /* Short packet? */
240 if (status < hlen + (sizeof *icfrom)) {
241 return ISC_R_SUCCESS;
242 }
243
244 len = status - hlen;
245 icfrom = (struct icmp *)(icbuf + hlen);
246
247 /* Silently discard ICMP packets that aren't echoreplies. */
248 if (icfrom -> icmp_type != ICMP_ECHOREPLY) {
249 return ISC_R_SUCCESS;
250 }
251
252 /* If we were given a second-stage handler, call it. */
253 if (state -> icmp_handler) {
254 memcpy (ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
255 ia.len = sizeof from.sin_addr;
256
257 #if defined (TRACING)
258 if (trace_record ()) {
259 ia.len = htonl(ia.len);
260 iov [0].buf = (char *)&ia;
261 iov [0].len = sizeof ia;
262 iov [1].buf = (char *)icbuf;
263 iov [1].len = len;
264 trace_write_packet_iov (trace_icmp_input, 2, iov, MDL);
265 ia.len = ntohl(ia.len);
266 }
267 #endif
268 (*state -> icmp_handler) (ia, icbuf, len);
269 }
270 return ISC_R_SUCCESS;
271 }
272
273 #if defined (TRACING)
trace_icmp_input_input(trace_type_t * ttype,unsigned length,char * buf)274 void trace_icmp_input_input (trace_type_t *ttype, unsigned length, char *buf)
275 {
276 struct iaddr *ia;
277 u_int8_t *icbuf;
278 ia = (struct iaddr *)buf;
279 ia->len = ntohl(ia->len);
280 icbuf = (u_int8_t *)(ia + 1);
281 if (icmp_state -> icmp_handler)
282 (*icmp_state -> icmp_handler) (*ia, icbuf,
283 (int)(length - sizeof ia));
284 }
285
trace_icmp_input_stop(trace_type_t * ttype)286 void trace_icmp_input_stop (trace_type_t *ttype) { }
287
trace_icmp_output_input(trace_type_t * ttype,unsigned length,char * buf)288 void trace_icmp_output_input (trace_type_t *ttype, unsigned length, char *buf)
289 {
290 struct iaddr ia;
291
292 if (length != (sizeof (struct icmp) + sizeof (ia))) {
293 log_error ("trace_icmp_output_input: data size mismatch %d:%d",
294 length, (int)(sizeof (struct icmp) + sizeof (ia)));
295 return;
296 }
297 ia.len = 4;
298 memcpy (ia.iabuf, buf, 4);
299
300 log_error ("trace_icmp_output_input: unsent ping to %s", piaddr (ia));
301 }
302
trace_icmp_output_stop(trace_type_t * ttype)303 void trace_icmp_output_stop (trace_type_t *ttype) { }
304 #endif /* TRACING */
305