root / slirp / ip_icmp.c @ f97572e5
History | View | Annotate | Download (10.5 kB)
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 |
* 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.
|
20 |
*
|
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
|
31 |
* SUCH DAMAGE.
|
32 |
*
|
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
|
35 |
*/
|
36 |
|
37 |
#include "slirp.h" |
38 |
#include "ip_icmp.h" |
39 |
|
40 |
#ifdef LOG_ENABLED
|
41 |
struct icmpstat icmpstat;
|
42 |
#endif
|
43 |
|
44 |
/* The message sent when emulating PING */
|
45 |
/* Be nice and tell them it's just a pseudo-ping packet */
|
46 |
const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n"; |
47 |
|
48 |
/* list of actions for icmp_error() on RX of an icmp message */
|
49 |
static const int icmp_flush[19] = { |
50 |
/* ECHO REPLY (0) */ 0, |
51 |
1,
|
52 |
1,
|
53 |
/* DEST UNREACH (3) */ 1, |
54 |
/* SOURCE QUENCH (4)*/ 1, |
55 |
/* REDIRECT (5) */ 1, |
56 |
1,
|
57 |
1,
|
58 |
/* ECHO (8) */ 0, |
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, |
65 |
/* INFO (15) */ 0, |
66 |
/* INFO REPLY (16) */ 0, |
67 |
/* ADDR MASK (17) */ 0, |
68 |
/* ADDR MASK REPLY (18) */ 0 |
69 |
}; |
70 |
|
71 |
/*
|
72 |
* Process a received ICMP message.
|
73 |
*/
|
74 |
void
|
75 |
icmp_input(m, hlen) |
76 |
struct mbuf *m;
|
77 |
int hlen;
|
78 |
{ |
79 |
register struct icmp *icp; |
80 |
register struct ip *ip=mtod(m, struct ip *); |
81 |
int icmplen=ip->ip_len;
|
82 |
/* int code; */
|
83 |
|
84 |
DEBUG_CALL("icmp_input");
|
85 |
DEBUG_ARG("m = %lx", (long )m); |
86 |
DEBUG_ARG("m_len = %d", m->m_len);
|
87 |
|
88 |
STAT(icmpstat.icps_received++); |
89 |
|
90 |
/*
|
91 |
* Locate icmp structure in mbuf, and check
|
92 |
* that its not corrupted and of at least minimum length.
|
93 |
*/
|
94 |
if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */ |
95 |
STAT(icmpstat.icps_tooshort++); |
96 |
freeit:
|
97 |
m_freem(m); |
98 |
goto end_error;
|
99 |
} |
100 |
|
101 |
m->m_len -= hlen; |
102 |
m->m_data += hlen; |
103 |
icp = mtod(m, struct icmp *);
|
104 |
if (cksum(m, icmplen)) {
|
105 |
STAT(icmpstat.icps_checksum++); |
106 |
goto freeit;
|
107 |
} |
108 |
m->m_len += hlen; |
109 |
m->m_data -= hlen; |
110 |
|
111 |
/* icmpstat.icps_inhist[icp->icmp_type]++; */
|
112 |
/* code = icp->icmp_code; */
|
113 |
|
114 |
DEBUG_ARG("icmp_type = %d", icp->icmp_type);
|
115 |
switch (icp->icmp_type) {
|
116 |
case ICMP_ECHO:
|
117 |
icp->icmp_type = ICMP_ECHOREPLY; |
118 |
ip->ip_len += hlen; /* since ip_input subtracts this */
|
119 |
if (ip->ip_dst.s_addr == alias_addr.s_addr) {
|
120 |
icmp_reflect(m); |
121 |
} else {
|
122 |
struct socket *so;
|
123 |
struct sockaddr_in addr;
|
124 |
if ((so = socreate()) == NULL) goto freeit; |
125 |
if(udp_attach(so) == -1) { |
126 |
DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n",
|
127 |
errno,strerror(errno))); |
128 |
sofree(so); |
129 |
m_free(m); |
130 |
goto end_error;
|
131 |
} |
132 |
so->so_m = m; |
133 |
so->so_faddr = ip->ip_dst; |
134 |
so->so_fport = htons(7);
|
135 |
so->so_laddr = ip->ip_src; |
136 |
so->so_lport = htons(9);
|
137 |
so->so_iptos = ip->ip_tos; |
138 |
so->so_type = IPPROTO_ICMP; |
139 |
so->so_state = SS_ISFCONNECTED; |
140 |
|
141 |
/* Send the packet */
|
142 |
addr.sin_family = AF_INET; |
143 |
if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) { |
144 |
/* It's an alias */
|
145 |
switch(ntohl(so->so_faddr.s_addr) & 0xff) { |
146 |
case CTL_DNS:
|
147 |
addr.sin_addr = dns_addr; |
148 |
break;
|
149 |
case CTL_ALIAS:
|
150 |
default:
|
151 |
addr.sin_addr = loopback_addr; |
152 |
break;
|
153 |
} |
154 |
} else {
|
155 |
addr.sin_addr = so->so_faddr; |
156 |
} |
157 |
addr.sin_port = so->so_fport; |
158 |
if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0, |
159 |
(struct sockaddr *)&addr, sizeof(addr)) == -1) { |
160 |
DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
|
161 |
errno,strerror(errno))); |
162 |
icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
|
163 |
udp_detach(so); |
164 |
} |
165 |
} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
|
166 |
break;
|
167 |
case ICMP_UNREACH:
|
168 |
/* XXX? report error? close socket? */
|
169 |
case ICMP_TIMXCEED:
|
170 |
case ICMP_PARAMPROB:
|
171 |
case ICMP_SOURCEQUENCH:
|
172 |
case ICMP_TSTAMP:
|
173 |
case ICMP_MASKREQ:
|
174 |
case ICMP_REDIRECT:
|
175 |
STAT(icmpstat.icps_notsupp++); |
176 |
m_freem(m); |
177 |
break;
|
178 |
|
179 |
default:
|
180 |
STAT(icmpstat.icps_badtype++); |
181 |
m_freem(m); |
182 |
} /* swith */
|
183 |
|
184 |
end_error:
|
185 |
/* m is m_free()'d xor put in a socket xor or given to ip_send */
|
186 |
return;
|
187 |
} |
188 |
|
189 |
|
190 |
/*
|
191 |
* Send an ICMP message in response to a situation
|
192 |
*
|
193 |
* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
|
194 |
* MUST NOT change this header information.
|
195 |
* MUST NOT reply to a multicast/broadcast IP address.
|
196 |
* MUST NOT reply to a multicast/broadcast MAC address.
|
197 |
* MUST reply to only the first fragment.
|
198 |
*/
|
199 |
/*
|
200 |
* Send ICMP_UNREACH back to the source regarding msrc.
|
201 |
* mbuf *msrc is used as a template, but is NOT m_free()'d.
|
202 |
* It is reported as the bad ip packet. The header should
|
203 |
* be fully correct and in host byte order.
|
204 |
* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
|
205 |
* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
|
206 |
*/
|
207 |
|
208 |
#define ICMP_MAXDATALEN (IP_MSS-28) |
209 |
void
|
210 |
icmp_error(msrc, type, code, minsize, message) |
211 |
struct mbuf *msrc;
|
212 |
u_char type; |
213 |
u_char code; |
214 |
int minsize;
|
215 |
char *message;
|
216 |
{ |
217 |
unsigned hlen, shlen, s_ip_len;
|
218 |
register struct ip *ip; |
219 |
register struct icmp *icp; |
220 |
register struct mbuf *m; |
221 |
|
222 |
DEBUG_CALL("icmp_error");
|
223 |
DEBUG_ARG("msrc = %lx", (long )msrc); |
224 |
DEBUG_ARG("msrc_len = %d", msrc->m_len);
|
225 |
|
226 |
if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error; |
227 |
|
228 |
/* check msrc */
|
229 |
if(!msrc) goto end_error; |
230 |
ip = mtod(msrc, struct ip *);
|
231 |
#if DEBUG
|
232 |
{ char bufa[20], bufb[20]; |
233 |
strcpy(bufa, inet_ntoa(ip->ip_src)); |
234 |
strcpy(bufb, inet_ntoa(ip->ip_dst)); |
235 |
DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
|
236 |
} |
237 |
#endif
|
238 |
if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */ |
239 |
|
240 |
shlen=ip->ip_hl << 2;
|
241 |
s_ip_len=ip->ip_len; |
242 |
if(ip->ip_p == IPPROTO_ICMP) {
|
243 |
icp = (struct icmp *)((char *)ip + shlen); |
244 |
/*
|
245 |
* Assume any unknown ICMP type is an error. This isn't
|
246 |
* specified by the RFC, but think about it..
|
247 |
*/
|
248 |
if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error; |
249 |
} |
250 |
|
251 |
/* make a copy */
|
252 |
if(!(m=m_get())) goto end_error; /* get mbuf */ |
253 |
{ int new_m_size;
|
254 |
new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN; |
255 |
if(new_m_size>m->m_size) m_inc(m, new_m_size);
|
256 |
} |
257 |
memcpy(m->m_data, msrc->m_data, msrc->m_len); |
258 |
m->m_len = msrc->m_len; /* copy msrc to m */
|
259 |
|
260 |
/* make the header of the reply packet */
|
261 |
ip = mtod(m, struct ip *);
|
262 |
hlen= sizeof(struct ip ); /* no options in reply */ |
263 |
|
264 |
/* fill in icmp */
|
265 |
m->m_data += hlen; |
266 |
m->m_len -= hlen; |
267 |
|
268 |
icp = mtod(m, struct icmp *);
|
269 |
|
270 |
if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */ |
271 |
else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */ |
272 |
s_ip_len=ICMP_MAXDATALEN; |
273 |
|
274 |
m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */
|
275 |
|
276 |
/* min. size = 8+sizeof(struct ip)+8 */
|
277 |
|
278 |
icp->icmp_type = type; |
279 |
icp->icmp_code = code; |
280 |
icp->icmp_id = 0;
|
281 |
icp->icmp_seq = 0;
|
282 |
|
283 |
memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
|
284 |
HTONS(icp->icmp_ip.ip_len); |
285 |
HTONS(icp->icmp_ip.ip_id); |
286 |
HTONS(icp->icmp_ip.ip_off); |
287 |
|
288 |
#if DEBUG
|
289 |
if(message) { /* DEBUG : append message to ICMP packet */ |
290 |
int message_len;
|
291 |
char *cpnt;
|
292 |
message_len=strlen(message); |
293 |
if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN;
|
294 |
cpnt=(char *)m->m_data+m->m_len;
|
295 |
memcpy(cpnt, message, message_len); |
296 |
m->m_len+=message_len; |
297 |
} |
298 |
#endif
|
299 |
|
300 |
icp->icmp_cksum = 0;
|
301 |
icp->icmp_cksum = cksum(m, m->m_len); |
302 |
|
303 |
m->m_data -= hlen; |
304 |
m->m_len += hlen; |
305 |
|
306 |
/* fill in ip */
|
307 |
ip->ip_hl = hlen >> 2;
|
308 |
ip->ip_len = m->m_len; |
309 |
|
310 |
ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */ |
311 |
|
312 |
ip->ip_ttl = MAXTTL; |
313 |
ip->ip_p = IPPROTO_ICMP; |
314 |
ip->ip_dst = ip->ip_src; /* ip adresses */
|
315 |
ip->ip_src = alias_addr; |
316 |
|
317 |
(void ) ip_output((struct socket *)NULL, m); |
318 |
|
319 |
STAT(icmpstat.icps_reflect++); |
320 |
|
321 |
end_error:
|
322 |
return;
|
323 |
} |
324 |
#undef ICMP_MAXDATALEN
|
325 |
|
326 |
/*
|
327 |
* Reflect the ip packet back to the source
|
328 |
*/
|
329 |
void
|
330 |
icmp_reflect(m) |
331 |
struct mbuf *m;
|
332 |
{ |
333 |
register struct ip *ip = mtod(m, struct ip *); |
334 |
int hlen = ip->ip_hl << 2; |
335 |
int optlen = hlen - sizeof(struct ip ); |
336 |
register struct icmp *icp; |
337 |
|
338 |
/*
|
339 |
* Send an icmp packet back to the ip level,
|
340 |
* after supplying a checksum.
|
341 |
*/
|
342 |
m->m_data += hlen; |
343 |
m->m_len -= hlen; |
344 |
icp = mtod(m, struct icmp *);
|
345 |
|
346 |
icp->icmp_cksum = 0;
|
347 |
icp->icmp_cksum = cksum(m, ip->ip_len - hlen); |
348 |
|
349 |
m->m_data -= hlen; |
350 |
m->m_len += hlen; |
351 |
|
352 |
/* fill in ip */
|
353 |
if (optlen > 0) { |
354 |
/*
|
355 |
* Strip out original options by copying rest of first
|
356 |
* mbuf's data back, and adjust the IP length.
|
357 |
*/
|
358 |
memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen,
|
359 |
(unsigned )(m->m_len - hlen));
|
360 |
hlen -= optlen; |
361 |
ip->ip_hl = hlen >> 2;
|
362 |
ip->ip_len -= optlen; |
363 |
m->m_len -= optlen; |
364 |
} |
365 |
|
366 |
ip->ip_ttl = MAXTTL; |
367 |
{ /* swap */
|
368 |
struct in_addr icmp_dst;
|
369 |
icmp_dst = ip->ip_dst; |
370 |
ip->ip_dst = ip->ip_src; |
371 |
ip->ip_src = icmp_dst; |
372 |
} |
373 |
|
374 |
(void ) ip_output((struct socket *)NULL, m); |
375 |
|
376 |
STAT(icmpstat.icps_reflect++); |
377 |
} |