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
42 struct icmpstat icmpstat
;
44 /* The message sent when emulating PING */
45 /* Be nice and tell them it's just a psuedo-ping packet */
46 char icmp_ping_msg
[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
48 /* list of actions for icmp_error() on RX of an icmp message */
49 static int icmp_flush
[19] = {
50 /* ECHO REPLY (0) */ 0,
53 /* DEST UNREACH (3) */ 1,
54 /* SOURCE QUENCH (4)*/ 1,
59 /* ROUTERADVERT (9) */ 1,
60 /* ROUTERSOLICIT (10) */ 1,
61 /* TIME EXCEEDED (11) */ 1,
62 /* PARAMETER PROBLEM (12) */ 1,
63 /* TIMESTAMP (13) */ 0,
64 /* TIMESTAMP REPLY (14) */ 0,
66 /* INFO REPLY (16) */ 0,
67 /* ADDR MASK (17) */ 0,
68 /* ADDR MASK REPLY (18) */ 0
72 * Process a received ICMP message.
79 register struct icmp
*icp
;
80 register struct ip
*ip
=mtod(m
, struct ip
*);
81 int icmplen
=ip
->ip_len
;
84 DEBUG_CALL("icmp_input");
85 DEBUG_ARG("m = %lx", (long )m
);
86 DEBUG_ARG("m_len = %d", m
->m_len
);
88 icmpstat
.icps_received
++;
91 * Locate icmp structure in mbuf, and check
92 * that its not corrupted and of at least minimum length.
94 if (icmplen
< ICMP_MINLEN
) { /* min 8 bytes payload */
95 icmpstat
.icps_tooshort
++;
103 icp
= mtod(m
, struct icmp
*);
104 if (cksum(m
, icmplen
)) {
105 icmpstat
.icps_checksum
++;
111 /* icmpstat.icps_inhist[icp->icmp_type]++; */
112 /* code = icp->icmp_code; */
114 DEBUG_ARG("icmp_type = %d", icp
->icmp_type
);
115 switch (icp
->icmp_type
) {
117 icp
->icmp_type
= ICMP_ECHOREPLY
;
118 ip
->ip_len
+= hlen
; /* since ip_input subtracts this */
119 if (ip
->ip_dst
.s_addr
== our_addr
.s_addr
||
120 (ip
->ip_dst
.s_addr
== (special_addr
.s_addr
|htonl(CTL_ALIAS
))) ) {
124 struct sockaddr_in addr
;
125 if ((so
= socreate()) == NULL
) goto freeit
;
126 if(udp_attach(so
) == -1) {
127 DEBUG_MISC((dfd
,"icmp_input udp_attach errno = %d-%s\n",
128 errno
,strerror(errno
)));
134 so
->so_faddr
= ip
->ip_dst
;
135 so
->so_fport
= htons(7);
136 so
->so_laddr
= ip
->ip_src
;
137 so
->so_lport
= htons(9);
138 so
->so_iptos
= ip
->ip_tos
;
139 so
->so_type
= IPPROTO_ICMP
;
140 so
->so_state
= SS_ISFCONNECTED
;
142 /* Send the packet */
143 addr
.sin_family
= AF_INET
;
144 if ((so
->so_faddr
.s_addr
& htonl(0xffffff00)) == special_addr
.s_addr
) {
146 switch(ntohl(so
->so_faddr
.s_addr
) & 0xff) {
148 addr
.sin_addr
= dns_addr
;
152 addr
.sin_addr
= loopback_addr
;
156 addr
.sin_addr
= so
->so_faddr
;
158 addr
.sin_port
= so
->so_fport
;
159 if(sendto(so
->s
, icmp_ping_msg
, strlen(icmp_ping_msg
), 0,
160 (struct sockaddr
*)&addr
, sizeof(addr
)) == -1) {
161 DEBUG_MISC((dfd
,"icmp_input udp sendto tx errno = %d-%s\n",
162 errno
,strerror(errno
)));
163 icmp_error(m
, ICMP_UNREACH
,ICMP_UNREACH_NET
, 0,strerror(errno
));
166 } /* if ip->ip_dst.s_addr == our_addr.s_addr */
169 /* XXX? report error? close socket? */
172 case ICMP_SOURCEQUENCH
:
176 icmpstat
.icps_notsupp
++;
181 icmpstat
.icps_badtype
++;
186 /* m is m_free()'d xor put in a socket xor or given to ip_send */
192 * Send an ICMP message in response to a situation
194 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
195 * MUST NOT change this header information.
196 * MUST NOT reply to a multicast/broadcast IP address.
197 * MUST NOT reply to a multicast/broadcast MAC address.
198 * MUST reply to only the first fragment.
201 * Send ICMP_UNREACH back to the source regarding msrc.
202 * mbuf *msrc is used as a template, but is NOT m_free()'d.
203 * It is reported as the bad ip packet. The header should
204 * be fully correct and in host byte order.
205 * ICMP fragmentation is illegal. All machines must accept 576 bytes in one
206 * packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
209 #define ICMP_MAXDATALEN (IP_MSS-28)
211 icmp_error(msrc
, type
, code
, minsize
, message
)
218 unsigned hlen
, shlen
, s_ip_len
;
219 register struct ip
*ip
;
220 register struct icmp
*icp
;
221 register struct mbuf
*m
;
223 DEBUG_CALL("icmp_error");
224 DEBUG_ARG("msrc = %lx", (long )msrc
);
225 DEBUG_ARG("msrc_len = %d", msrc
->m_len
);
227 if(type
!=ICMP_UNREACH
&& type
!=ICMP_TIMXCEED
) goto end_error
;
230 if(!msrc
) goto end_error
;
231 ip
= mtod(msrc
, struct ip
*);
233 { char bufa
[20], bufb
[20];
234 strcpy(bufa
, inet_ntoa(ip
->ip_src
));
235 strcpy(bufb
, inet_ntoa(ip
->ip_dst
));
236 DEBUG_MISC((dfd
, " %.16s to %.16s\n", bufa
, bufb
));
239 if(ip
->ip_off
& IP_OFFMASK
) goto end_error
; /* Only reply to fragment 0 */
241 shlen
=ip
->ip_hl
<< 2;
243 if(ip
->ip_p
== IPPROTO_ICMP
) {
244 icp
= (struct icmp
*)((char *)ip
+ shlen
);
246 * Assume any unknown ICMP type is an error. This isn't
247 * specified by the RFC, but think about it..
249 if(icp
->icmp_type
>18 || icmp_flush
[icp
->icmp_type
]) goto end_error
;
253 if(!(m
=m_get())) goto end_error
; /* get mbuf */
255 new_m_size
=sizeof(struct ip
)+ICMP_MINLEN
+msrc
->m_len
+ICMP_MAXDATALEN
;
256 if(new_m_size
>m
->m_size
) m_inc(m
, new_m_size
);
258 memcpy(m
->m_data
, msrc
->m_data
, msrc
->m_len
);
259 m
->m_len
= msrc
->m_len
; /* copy msrc to m */
261 /* make the header of the reply packet */
262 ip
= mtod(m
, struct ip
*);
263 hlen
= sizeof(struct ip
); /* no options in reply */
269 icp
= mtod(m
, struct icmp
*);
271 if(minsize
) s_ip_len
=shlen
+ICMP_MINLEN
; /* return header+8b only */
272 else if(s_ip_len
>ICMP_MAXDATALEN
) /* maximum size */
273 s_ip_len
=ICMP_MAXDATALEN
;
275 m
->m_len
=ICMP_MINLEN
+s_ip_len
; /* 8 bytes ICMP header */
277 /* min. size = 8+sizeof(struct ip)+8 */
279 icp
->icmp_type
= type
;
280 icp
->icmp_code
= code
;
284 memcpy(&icp
->icmp_ip
, msrc
->m_data
, s_ip_len
); /* report the ip packet */
285 HTONS(icp
->icmp_ip
.ip_len
);
286 HTONS(icp
->icmp_ip
.ip_id
);
287 HTONS(icp
->icmp_ip
.ip_off
);
290 if(message
) { /* DEBUG : append message to ICMP packet */
293 message_len
=strlen(message
);
294 if(message_len
>ICMP_MAXDATALEN
) message_len
=ICMP_MAXDATALEN
;
295 cpnt
=(char *)m
->m_data
+m
->m_len
;
296 memcpy(cpnt
, message
, message_len
);
297 m
->m_len
+=message_len
;
302 icp
->icmp_cksum
= cksum(m
, m
->m_len
);
308 ip
->ip_hl
= hlen
>> 2;
309 ip
->ip_len
= m
->m_len
;
311 ip
->ip_tos
=((ip
->ip_tos
& 0x1E) | 0xC0); /* high priority for errors */
314 ip
->ip_p
= IPPROTO_ICMP
;
315 ip
->ip_dst
= ip
->ip_src
; /* ip adresses */
316 ip
->ip_src
= our_addr
;
318 (void ) ip_output((struct socket
*)NULL
, m
);
320 icmpstat
.icps_reflect
++;
325 #undef ICMP_MAXDATALEN
328 * Reflect the ip packet back to the source
334 register struct ip
*ip
= mtod(m
, struct ip
*);
335 int hlen
= ip
->ip_hl
<< 2;
336 int optlen
= hlen
- sizeof(struct ip
);
337 register struct icmp
*icp
;
340 * Send an icmp packet back to the ip level,
341 * after supplying a checksum.
345 icp
= mtod(m
, struct icmp
*);
348 icp
->icmp_cksum
= cksum(m
, ip
->ip_len
- hlen
);
356 * Strip out original options by copying rest of first
357 * mbuf's data back, and adjust the IP length.
359 memmove((caddr_t
)(ip
+ 1), (caddr_t
)ip
+ hlen
,
360 (unsigned )(m
->m_len
- hlen
));
362 ip
->ip_hl
= hlen
>> 2;
363 ip
->ip_len
-= optlen
;
369 struct in_addr icmp_dst
;
370 icmp_dst
= ip
->ip_dst
;
371 ip
->ip_dst
= ip
->ip_src
;
372 ip
->ip_src
= icmp_dst
;
375 (void ) ip_output((struct socket
*)NULL
, m
);
377 icmpstat
.icps_reflect
++;