2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
34 * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
40 struct icmpstat icmpstat
;
42 /* The message sent when emulating PING */
43 /* Be nice and tell them it's just a psuedo-ping packet */
44 char icmp_ping_msg
[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
46 /* list of actions for icmp_error() on RX of an icmp message */
47 static int icmp_flush
[19] = {
48 /* ECHO REPLY (0) */ 0,
51 /* DEST UNREACH (3) */ 1,
52 /* SOURCE QUENCH (4)*/ 1,
57 /* ROUTERADVERT (9) */ 1,
58 /* ROUTERSOLICIT (10) */ 1,
59 /* TIME EXCEEDED (11) */ 1,
60 /* PARAMETER PROBLEM (12) */ 1,
61 /* TIMESTAMP (13) */ 0,
62 /* TIMESTAMP REPLY (14) */ 0,
64 /* INFO REPLY (16) */ 0,
65 /* ADDR MASK (17) */ 0,
66 /* ADDR MASK REPLY (18) */ 0
70 * Process a received ICMP message.
77 register struct icmp
*icp
;
78 register struct ip
*ip
=mtod(m
, struct ip
*);
79 int icmplen
=ip
->ip_len
;
82 DEBUG_CALL("icmp_input");
83 DEBUG_ARG("m = %lx", (long )m
);
84 DEBUG_ARG("m_len = %d", m
->m_len
);
86 icmpstat
.icps_received
++;
89 * Locate icmp structure in mbuf, and check
90 * that its not corrupted and of at least minimum length.
92 if (icmplen
< ICMP_MINLEN
) { /* min 8 bytes payload */
93 icmpstat
.icps_tooshort
++;
101 icp
= mtod(m
, struct icmp
*);
102 if (cksum(m
, icmplen
)) {
103 icmpstat
.icps_checksum
++;
109 /* icmpstat.icps_inhist[icp->icmp_type]++; */
110 /* code = icp->icmp_code; */
112 DEBUG_ARG("icmp_type = %d", icp
->icmp_type
);
113 switch (icp
->icmp_type
) {
115 icp
->icmp_type
= ICMP_ECHOREPLY
;
116 ip
->ip_len
+= hlen
; /* since ip_input subtracts this */
117 if (ip
->ip_dst
.s_addr
== our_addr
.s_addr
||
118 (ip
->ip_dst
.s_addr
== (special_addr
.s_addr
|htonl(CTL_ALIAS
))) ) {
122 struct sockaddr_in addr
;
123 if ((so
= socreate()) == NULL
) goto freeit
;
124 if(udp_attach(so
) == -1) {
125 DEBUG_MISC((dfd
,"icmp_input udp_attach errno = %d-%s\n",
126 errno
,strerror(errno
)));
132 so
->so_faddr
= ip
->ip_dst
;
133 so
->so_fport
= htons(7);
134 so
->so_laddr
= ip
->ip_src
;
135 so
->so_lport
= htons(9);
136 so
->so_iptos
= ip
->ip_tos
;
137 so
->so_type
= IPPROTO_ICMP
;
138 so
->so_state
= SS_ISFCONNECTED
;
140 /* Send the packet */
141 addr
.sin_family
= AF_INET
;
142 if ((so
->so_faddr
.s_addr
& htonl(0xffffff00)) == special_addr
.s_addr
) {
144 switch(ntohl(so
->so_faddr
.s_addr
) & 0xff) {
146 addr
.sin_addr
= dns_addr
;
150 addr
.sin_addr
= loopback_addr
;
154 addr
.sin_addr
= so
->so_faddr
;
156 addr
.sin_port
= so
->so_fport
;
157 if(sendto(so
->s
, icmp_ping_msg
, strlen(icmp_ping_msg
), 0,
158 (struct sockaddr
*)&addr
, sizeof(addr
)) == -1) {
159 DEBUG_MISC((dfd
,"icmp_input udp sendto tx errno = %d-%s\n",
160 errno
,strerror(errno
)));
161 icmp_error(m
, ICMP_UNREACH
,ICMP_UNREACH_NET
, 0,strerror(errno
));
164 } /* if ip->ip_dst.s_addr == our_addr.s_addr */
167 /* XXX? report error? close socket? */
170 case ICMP_SOURCEQUENCH
:
174 icmpstat
.icps_notsupp
++;
179 icmpstat
.icps_badtype
++;
184 /* m is m_free()'d xor put in a socket xor or given to ip_send */
190 * Send an ICMP message in response to a situation
192 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
193 * MUST NOT change this header information.
194 * MUST NOT reply to a multicast/broadcast IP address.
195 * MUST NOT reply to a multicast/broadcast MAC address.
196 * MUST reply to only the first fragment.
199 * Send ICMP_UNREACH back to the source regarding msrc.
200 * mbuf *msrc is used as a template, but is NOT m_free()'d.
201 * It is reported as the bad ip packet. The header should
202 * be fully correct and in host byte order.
203 * ICMP fragmentation is illegal. All machines must accept 576 bytes in one
204 * packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
207 #define ICMP_MAXDATALEN (IP_MSS-28)
209 icmp_error(msrc
, type
, code
, minsize
, message
)
216 unsigned hlen
, shlen
, s_ip_len
;
217 register struct ip
*ip
;
218 register struct icmp
*icp
;
219 register struct mbuf
*m
;
221 DEBUG_CALL("icmp_error");
222 DEBUG_ARG("msrc = %lx", (long )msrc
);
223 DEBUG_ARG("msrc_len = %d", msrc
->m_len
);
225 if(type
!=ICMP_UNREACH
&& type
!=ICMP_TIMXCEED
) goto end_error
;
228 if(!msrc
) goto end_error
;
229 ip
= mtod(msrc
, struct ip
*);
231 { char bufa
[20], bufb
[20];
232 strcpy(bufa
, inet_ntoa(ip
->ip_src
));
233 strcpy(bufb
, inet_ntoa(ip
->ip_dst
));
234 DEBUG_MISC((dfd
, " %.16s to %.16s\n", bufa
, bufb
));
237 if(ip
->ip_off
& IP_OFFMASK
) goto end_error
; /* Only reply to fragment 0 */
239 shlen
=ip
->ip_hl
<< 2;
241 if(ip
->ip_p
== IPPROTO_ICMP
) {
242 icp
= (struct icmp
*)((char *)ip
+ shlen
);
244 * Assume any unknown ICMP type is an error. This isn't
245 * specified by the RFC, but think about it..
247 if(icp
->icmp_type
>18 || icmp_flush
[icp
->icmp_type
]) goto end_error
;
251 if(!(m
=m_get())) goto end_error
; /* get mbuf */
253 new_m_size
=sizeof(struct ip
)+ICMP_MINLEN
+msrc
->m_len
+ICMP_MAXDATALEN
;
254 if(new_m_size
>m
->m_size
) m_inc(m
, new_m_size
);
256 memcpy(m
->m_data
, msrc
->m_data
, msrc
->m_len
);
257 m
->m_len
= msrc
->m_len
; /* copy msrc to m */
259 /* make the header of the reply packet */
260 ip
= mtod(m
, struct ip
*);
261 hlen
= sizeof(struct ip
); /* no options in reply */
267 icp
= mtod(m
, struct icmp
*);
269 if(minsize
) s_ip_len
=shlen
+ICMP_MINLEN
; /* return header+8b only */
270 else if(s_ip_len
>ICMP_MAXDATALEN
) /* maximum size */
271 s_ip_len
=ICMP_MAXDATALEN
;
273 m
->m_len
=ICMP_MINLEN
+s_ip_len
; /* 8 bytes ICMP header */
275 /* min. size = 8+sizeof(struct ip)+8 */
277 icp
->icmp_type
= type
;
278 icp
->icmp_code
= code
;
282 memcpy(&icp
->icmp_ip
, msrc
->m_data
, s_ip_len
); /* report the ip packet */
283 HTONS(icp
->icmp_ip
.ip_len
);
284 HTONS(icp
->icmp_ip
.ip_id
);
285 HTONS(icp
->icmp_ip
.ip_off
);
288 if(message
) { /* DEBUG : append message to ICMP packet */
291 message_len
=strlen(message
);
292 if(message_len
>ICMP_MAXDATALEN
) message_len
=ICMP_MAXDATALEN
;
293 cpnt
=(char *)m
->m_data
+m
->m_len
;
294 memcpy(cpnt
, message
, message_len
);
295 m
->m_len
+=message_len
;
300 icp
->icmp_cksum
= cksum(m
, m
->m_len
);
306 ip
->ip_hl
= hlen
>> 2;
307 ip
->ip_len
= m
->m_len
;
309 ip
->ip_tos
=((ip
->ip_tos
& 0x1E) | 0xC0); /* high priority for errors */
312 ip
->ip_p
= IPPROTO_ICMP
;
313 ip
->ip_dst
= ip
->ip_src
; /* ip adresses */
314 ip
->ip_src
= our_addr
;
316 (void ) ip_output((struct socket
*)NULL
, m
);
318 icmpstat
.icps_reflect
++;
323 #undef ICMP_MAXDATALEN
326 * Reflect the ip packet back to the source
332 register struct ip
*ip
= mtod(m
, struct ip
*);
333 int hlen
= ip
->ip_hl
<< 2;
334 int optlen
= hlen
- sizeof(struct ip
);
335 register struct icmp
*icp
;
338 * Send an icmp packet back to the ip level,
339 * after supplying a checksum.
343 icp
= mtod(m
, struct icmp
*);
346 icp
->icmp_cksum
= cksum(m
, ip
->ip_len
- hlen
);
354 * Strip out original options by copying rest of first
355 * mbuf's data back, and adjust the IP length.
357 memmove((caddr_t
)(ip
+ 1), (caddr_t
)ip
+ hlen
,
358 (unsigned )(m
->m_len
- hlen
));
360 ip
->ip_hl
= hlen
>> 2;
361 ip
->ip_len
-= optlen
;
367 struct in_addr icmp_dst
;
368 icmp_dst
= ip
->ip_dst
;
369 ip
->ip_dst
= ip
->ip_src
;
370 ip
->ip_src
= icmp_dst
;
373 (void ) ip_output((struct socket
*)NULL
, m
);
375 icmpstat
.icps_reflect
++;