1 |
gbeauche |
1.1 |
/* |
2 |
|
|
* Copyright (c) 1982, 1986, 1988, 1993 |
3 |
|
|
* The Regents of the University of California. All rights reserved. |
4 |
|
|
* |
5 |
|
|
* Redistribution and use in source and binary forms, with or without |
6 |
|
|
* modification, are permitted provided that the following conditions |
7 |
|
|
* are met: |
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 |
asvitkine |
1.3 |
* 3. Neither the name of the University nor the names of its contributors |
14 |
gbeauche |
1.1 |
* may be used to endorse or promote products derived from this software |
15 |
|
|
* without specific prior written permission. |
16 |
|
|
* |
17 |
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
18 |
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
19 |
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
20 |
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
21 |
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
22 |
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
23 |
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
24 |
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
25 |
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
26 |
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
27 |
|
|
* SUCH DAMAGE. |
28 |
|
|
* |
29 |
|
|
* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 |
30 |
|
|
* ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp |
31 |
|
|
*/ |
32 |
|
|
|
33 |
|
|
#include "slirp.h" |
34 |
|
|
#include "ip_icmp.h" |
35 |
|
|
|
36 |
|
|
struct icmpstat icmpstat; |
37 |
|
|
|
38 |
|
|
/* The message sent when emulating PING */ |
39 |
|
|
/* Be nice and tell them it's just a psuedo-ping packet */ |
40 |
|
|
char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n"; |
41 |
|
|
|
42 |
|
|
/* list of actions for icmp_error() on RX of an icmp message */ |
43 |
|
|
static int icmp_flush[19] = { |
44 |
|
|
/* ECHO REPLY (0) */ 0, |
45 |
|
|
1, |
46 |
|
|
1, |
47 |
|
|
/* DEST UNREACH (3) */ 1, |
48 |
|
|
/* SOURCE QUENCH (4)*/ 1, |
49 |
|
|
/* REDIRECT (5) */ 1, |
50 |
|
|
1, |
51 |
|
|
1, |
52 |
|
|
/* ECHO (8) */ 0, |
53 |
|
|
/* ROUTERADVERT (9) */ 1, |
54 |
|
|
/* ROUTERSOLICIT (10) */ 1, |
55 |
|
|
/* TIME EXCEEDED (11) */ 1, |
56 |
|
|
/* PARAMETER PROBLEM (12) */ 1, |
57 |
|
|
/* TIMESTAMP (13) */ 0, |
58 |
|
|
/* TIMESTAMP REPLY (14) */ 0, |
59 |
|
|
/* INFO (15) */ 0, |
60 |
|
|
/* INFO REPLY (16) */ 0, |
61 |
|
|
/* ADDR MASK (17) */ 0, |
62 |
|
|
/* ADDR MASK REPLY (18) */ 0 |
63 |
|
|
}; |
64 |
|
|
|
65 |
|
|
/* |
66 |
|
|
* Process a received ICMP message. |
67 |
|
|
*/ |
68 |
|
|
void |
69 |
|
|
icmp_input(m, hlen) |
70 |
|
|
struct mbuf *m; |
71 |
|
|
int hlen; |
72 |
|
|
{ |
73 |
|
|
register struct icmp *icp; |
74 |
|
|
register struct ip *ip=mtod(m, struct ip *); |
75 |
|
|
int icmplen=ip->ip_len; |
76 |
|
|
/* int code; */ |
77 |
|
|
|
78 |
|
|
DEBUG_CALL("icmp_input"); |
79 |
|
|
DEBUG_ARG("m = %lx", (long )m); |
80 |
|
|
DEBUG_ARG("m_len = %d", m->m_len); |
81 |
|
|
|
82 |
|
|
icmpstat.icps_received++; |
83 |
|
|
|
84 |
|
|
/* |
85 |
|
|
* Locate icmp structure in mbuf, and check |
86 |
|
|
* that its not corrupted and of at least minimum length. |
87 |
|
|
*/ |
88 |
|
|
if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */ |
89 |
|
|
icmpstat.icps_tooshort++; |
90 |
|
|
freeit: |
91 |
|
|
m_freem(m); |
92 |
|
|
goto end_error; |
93 |
|
|
} |
94 |
|
|
|
95 |
|
|
m->m_len -= hlen; |
96 |
|
|
m->m_data += hlen; |
97 |
|
|
icp = mtod(m, struct icmp *); |
98 |
|
|
if (cksum(m, icmplen)) { |
99 |
|
|
icmpstat.icps_checksum++; |
100 |
|
|
goto freeit; |
101 |
|
|
} |
102 |
|
|
m->m_len += hlen; |
103 |
|
|
m->m_data -= hlen; |
104 |
|
|
|
105 |
|
|
/* icmpstat.icps_inhist[icp->icmp_type]++; */ |
106 |
|
|
/* code = icp->icmp_code; */ |
107 |
|
|
|
108 |
|
|
DEBUG_ARG("icmp_type = %d", icp->icmp_type); |
109 |
|
|
switch (icp->icmp_type) { |
110 |
|
|
case ICMP_ECHO: |
111 |
|
|
icp->icmp_type = ICMP_ECHOREPLY; |
112 |
|
|
ip->ip_len += hlen; /* since ip_input subtracts this */ |
113 |
gbeauche |
1.2 |
if (ip->ip_dst.s_addr == alias_addr.s_addr) { |
114 |
gbeauche |
1.1 |
icmp_reflect(m); |
115 |
|
|
} else { |
116 |
|
|
struct socket *so; |
117 |
|
|
struct sockaddr_in addr; |
118 |
|
|
if ((so = socreate()) == NULL) goto freeit; |
119 |
|
|
if(udp_attach(so) == -1) { |
120 |
|
|
DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n", |
121 |
|
|
errno,strerror(errno))); |
122 |
|
|
sofree(so); |
123 |
|
|
m_free(m); |
124 |
|
|
goto end_error; |
125 |
|
|
} |
126 |
|
|
so->so_m = m; |
127 |
|
|
so->so_faddr = ip->ip_dst; |
128 |
|
|
so->so_fport = htons(7); |
129 |
|
|
so->so_laddr = ip->ip_src; |
130 |
|
|
so->so_lport = htons(9); |
131 |
|
|
so->so_iptos = ip->ip_tos; |
132 |
|
|
so->so_type = IPPROTO_ICMP; |
133 |
|
|
so->so_state = SS_ISFCONNECTED; |
134 |
|
|
|
135 |
|
|
/* Send the packet */ |
136 |
|
|
addr.sin_family = AF_INET; |
137 |
|
|
if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) { |
138 |
|
|
/* It's an alias */ |
139 |
|
|
switch(ntohl(so->so_faddr.s_addr) & 0xff) { |
140 |
|
|
case CTL_DNS: |
141 |
|
|
addr.sin_addr = dns_addr; |
142 |
|
|
break; |
143 |
|
|
case CTL_ALIAS: |
144 |
|
|
default: |
145 |
|
|
addr.sin_addr = loopback_addr; |
146 |
|
|
break; |
147 |
|
|
} |
148 |
|
|
} else { |
149 |
|
|
addr.sin_addr = so->so_faddr; |
150 |
|
|
} |
151 |
|
|
addr.sin_port = so->so_fport; |
152 |
|
|
if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0, |
153 |
|
|
(struct sockaddr *)&addr, sizeof(addr)) == -1) { |
154 |
|
|
DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n", |
155 |
|
|
errno,strerror(errno))); |
156 |
|
|
icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno)); |
157 |
|
|
udp_detach(so); |
158 |
|
|
} |
159 |
gbeauche |
1.2 |
} /* if ip->ip_dst.s_addr == alias_addr.s_addr */ |
160 |
gbeauche |
1.1 |
break; |
161 |
|
|
case ICMP_UNREACH: |
162 |
|
|
/* XXX? report error? close socket? */ |
163 |
|
|
case ICMP_TIMXCEED: |
164 |
|
|
case ICMP_PARAMPROB: |
165 |
|
|
case ICMP_SOURCEQUENCH: |
166 |
|
|
case ICMP_TSTAMP: |
167 |
|
|
case ICMP_MASKREQ: |
168 |
|
|
case ICMP_REDIRECT: |
169 |
|
|
icmpstat.icps_notsupp++; |
170 |
|
|
m_freem(m); |
171 |
|
|
break; |
172 |
|
|
|
173 |
|
|
default: |
174 |
|
|
icmpstat.icps_badtype++; |
175 |
|
|
m_freem(m); |
176 |
|
|
} /* swith */ |
177 |
|
|
|
178 |
|
|
end_error: |
179 |
|
|
/* m is m_free()'d xor put in a socket xor or given to ip_send */ |
180 |
|
|
return; |
181 |
|
|
} |
182 |
|
|
|
183 |
|
|
|
184 |
|
|
/* |
185 |
|
|
* Send an ICMP message in response to a situation |
186 |
|
|
* |
187 |
|
|
* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do). |
188 |
|
|
* MUST NOT change this header information. |
189 |
|
|
* MUST NOT reply to a multicast/broadcast IP address. |
190 |
|
|
* MUST NOT reply to a multicast/broadcast MAC address. |
191 |
|
|
* MUST reply to only the first fragment. |
192 |
|
|
*/ |
193 |
|
|
/* |
194 |
|
|
* Send ICMP_UNREACH back to the source regarding msrc. |
195 |
|
|
* mbuf *msrc is used as a template, but is NOT m_free()'d. |
196 |
|
|
* It is reported as the bad ip packet. The header should |
197 |
|
|
* be fully correct and in host byte order. |
198 |
|
|
* ICMP fragmentation is illegal. All machines must accept 576 bytes in one |
199 |
|
|
* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548 |
200 |
|
|
*/ |
201 |
|
|
|
202 |
|
|
#define ICMP_MAXDATALEN (IP_MSS-28) |
203 |
|
|
void |
204 |
|
|
icmp_error(msrc, type, code, minsize, message) |
205 |
|
|
struct mbuf *msrc; |
206 |
|
|
u_char type; |
207 |
|
|
u_char code; |
208 |
|
|
int minsize; |
209 |
|
|
char *message; |
210 |
|
|
{ |
211 |
|
|
unsigned hlen, shlen, s_ip_len; |
212 |
|
|
register struct ip *ip; |
213 |
|
|
register struct icmp *icp; |
214 |
|
|
register struct mbuf *m; |
215 |
|
|
|
216 |
|
|
DEBUG_CALL("icmp_error"); |
217 |
|
|
DEBUG_ARG("msrc = %lx", (long )msrc); |
218 |
|
|
DEBUG_ARG("msrc_len = %d", msrc->m_len); |
219 |
|
|
|
220 |
|
|
if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error; |
221 |
|
|
|
222 |
|
|
/* check msrc */ |
223 |
|
|
if(!msrc) goto end_error; |
224 |
|
|
ip = mtod(msrc, struct ip *); |
225 |
|
|
#if DEBUG |
226 |
|
|
{ char bufa[20], bufb[20]; |
227 |
|
|
strcpy(bufa, inet_ntoa(ip->ip_src)); |
228 |
|
|
strcpy(bufb, inet_ntoa(ip->ip_dst)); |
229 |
|
|
DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb)); |
230 |
|
|
} |
231 |
|
|
#endif |
232 |
|
|
if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */ |
233 |
|
|
|
234 |
|
|
shlen=ip->ip_hl << 2; |
235 |
|
|
s_ip_len=ip->ip_len; |
236 |
|
|
if(ip->ip_p == IPPROTO_ICMP) { |
237 |
|
|
icp = (struct icmp *)((char *)ip + shlen); |
238 |
|
|
/* |
239 |
|
|
* Assume any unknown ICMP type is an error. This isn't |
240 |
|
|
* specified by the RFC, but think about it.. |
241 |
|
|
*/ |
242 |
|
|
if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error; |
243 |
|
|
} |
244 |
|
|
|
245 |
|
|
/* make a copy */ |
246 |
|
|
if(!(m=m_get())) goto end_error; /* get mbuf */ |
247 |
|
|
{ int new_m_size; |
248 |
|
|
new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN; |
249 |
|
|
if(new_m_size>m->m_size) m_inc(m, new_m_size); |
250 |
|
|
} |
251 |
|
|
memcpy(m->m_data, msrc->m_data, msrc->m_len); |
252 |
|
|
m->m_len = msrc->m_len; /* copy msrc to m */ |
253 |
|
|
|
254 |
|
|
/* make the header of the reply packet */ |
255 |
|
|
ip = mtod(m, struct ip *); |
256 |
|
|
hlen= sizeof(struct ip ); /* no options in reply */ |
257 |
|
|
|
258 |
|
|
/* fill in icmp */ |
259 |
|
|
m->m_data += hlen; |
260 |
|
|
m->m_len -= hlen; |
261 |
|
|
|
262 |
|
|
icp = mtod(m, struct icmp *); |
263 |
|
|
|
264 |
|
|
if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */ |
265 |
|
|
else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */ |
266 |
|
|
s_ip_len=ICMP_MAXDATALEN; |
267 |
|
|
|
268 |
|
|
m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */ |
269 |
|
|
|
270 |
|
|
/* min. size = 8+sizeof(struct ip)+8 */ |
271 |
|
|
|
272 |
|
|
icp->icmp_type = type; |
273 |
|
|
icp->icmp_code = code; |
274 |
|
|
icp->icmp_id = 0; |
275 |
|
|
icp->icmp_seq = 0; |
276 |
|
|
|
277 |
|
|
memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */ |
278 |
|
|
HTONS(icp->icmp_ip.ip_len); |
279 |
|
|
HTONS(icp->icmp_ip.ip_id); |
280 |
|
|
HTONS(icp->icmp_ip.ip_off); |
281 |
|
|
|
282 |
|
|
#if DEBUG |
283 |
|
|
if(message) { /* DEBUG : append message to ICMP packet */ |
284 |
|
|
int message_len; |
285 |
|
|
char *cpnt; |
286 |
|
|
message_len=strlen(message); |
287 |
|
|
if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN; |
288 |
|
|
cpnt=(char *)m->m_data+m->m_len; |
289 |
|
|
memcpy(cpnt, message, message_len); |
290 |
|
|
m->m_len+=message_len; |
291 |
|
|
} |
292 |
|
|
#endif |
293 |
|
|
|
294 |
|
|
icp->icmp_cksum = 0; |
295 |
|
|
icp->icmp_cksum = cksum(m, m->m_len); |
296 |
|
|
|
297 |
|
|
m->m_data -= hlen; |
298 |
|
|
m->m_len += hlen; |
299 |
|
|
|
300 |
|
|
/* fill in ip */ |
301 |
|
|
ip->ip_hl = hlen >> 2; |
302 |
|
|
ip->ip_len = m->m_len; |
303 |
|
|
|
304 |
|
|
ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */ |
305 |
|
|
|
306 |
|
|
ip->ip_ttl = MAXTTL; |
307 |
|
|
ip->ip_p = IPPROTO_ICMP; |
308 |
|
|
ip->ip_dst = ip->ip_src; /* ip adresses */ |
309 |
gbeauche |
1.2 |
ip->ip_src = alias_addr; |
310 |
gbeauche |
1.1 |
|
311 |
|
|
(void ) ip_output((struct socket *)NULL, m); |
312 |
|
|
|
313 |
|
|
icmpstat.icps_reflect++; |
314 |
|
|
|
315 |
|
|
end_error: |
316 |
|
|
return; |
317 |
|
|
} |
318 |
|
|
#undef ICMP_MAXDATALEN |
319 |
|
|
|
320 |
|
|
/* |
321 |
|
|
* Reflect the ip packet back to the source |
322 |
|
|
*/ |
323 |
|
|
void |
324 |
|
|
icmp_reflect(m) |
325 |
|
|
struct mbuf *m; |
326 |
|
|
{ |
327 |
|
|
register struct ip *ip = mtod(m, struct ip *); |
328 |
|
|
int hlen = ip->ip_hl << 2; |
329 |
|
|
int optlen = hlen - sizeof(struct ip ); |
330 |
|
|
register struct icmp *icp; |
331 |
|
|
|
332 |
|
|
/* |
333 |
|
|
* Send an icmp packet back to the ip level, |
334 |
|
|
* after supplying a checksum. |
335 |
|
|
*/ |
336 |
|
|
m->m_data += hlen; |
337 |
|
|
m->m_len -= hlen; |
338 |
|
|
icp = mtod(m, struct icmp *); |
339 |
|
|
|
340 |
|
|
icp->icmp_cksum = 0; |
341 |
|
|
icp->icmp_cksum = cksum(m, ip->ip_len - hlen); |
342 |
|
|
|
343 |
|
|
m->m_data -= hlen; |
344 |
|
|
m->m_len += hlen; |
345 |
|
|
|
346 |
|
|
/* fill in ip */ |
347 |
|
|
if (optlen > 0) { |
348 |
|
|
/* |
349 |
|
|
* Strip out original options by copying rest of first |
350 |
|
|
* mbuf's data back, and adjust the IP length. |
351 |
|
|
*/ |
352 |
|
|
memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen, |
353 |
|
|
(unsigned )(m->m_len - hlen)); |
354 |
|
|
hlen -= optlen; |
355 |
|
|
ip->ip_hl = hlen >> 2; |
356 |
|
|
ip->ip_len -= optlen; |
357 |
|
|
m->m_len -= optlen; |
358 |
|
|
} |
359 |
|
|
|
360 |
|
|
ip->ip_ttl = MAXTTL; |
361 |
|
|
{ /* swap */ |
362 |
|
|
struct in_addr icmp_dst; |
363 |
|
|
icmp_dst = ip->ip_dst; |
364 |
|
|
ip->ip_dst = ip->ip_src; |
365 |
|
|
ip->ip_src = icmp_dst; |
366 |
|
|
} |
367 |
|
|
|
368 |
|
|
(void ) ip_output((struct socket *)NULL, m); |
369 |
|
|
|
370 |
|
|
icmpstat.icps_reflect++; |
371 |
|
|
} |