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f0cbd3ec FB |
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. | |
2f5f8996 | 13 | * 3. Neither the name of the University nor the names of its contributors |
f0cbd3ec FB |
14 | * 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 | ||
31a60e22 | 36 | #ifdef LOG_ENABLED |
f0cbd3ec | 37 | struct icmpstat icmpstat; |
31a60e22 | 38 | #endif |
f0cbd3ec FB |
39 | |
40 | /* The message sent when emulating PING */ | |
7878ff6b | 41 | /* Be nice and tell them it's just a pseudo-ping packet */ |
7ca699c8 | 42 | static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n"; |
f0cbd3ec FB |
43 | |
44 | /* list of actions for icmp_error() on RX of an icmp message */ | |
9634d903 | 45 | static const int icmp_flush[19] = { |
f0cbd3ec FB |
46 | /* ECHO REPLY (0) */ 0, |
47 | 1, | |
48 | 1, | |
49 | /* DEST UNREACH (3) */ 1, | |
50 | /* SOURCE QUENCH (4)*/ 1, | |
51 | /* REDIRECT (5) */ 1, | |
52 | 1, | |
53 | 1, | |
54 | /* ECHO (8) */ 0, | |
55 | /* ROUTERADVERT (9) */ 1, | |
56 | /* ROUTERSOLICIT (10) */ 1, | |
57 | /* TIME EXCEEDED (11) */ 1, | |
58 | /* PARAMETER PROBLEM (12) */ 1, | |
59 | /* TIMESTAMP (13) */ 0, | |
60 | /* TIMESTAMP REPLY (14) */ 0, | |
61 | /* INFO (15) */ 0, | |
62 | /* INFO REPLY (16) */ 0, | |
63 | /* ADDR MASK (17) */ 0, | |
5fafdf24 | 64 | /* ADDR MASK REPLY (18) */ 0 |
f0cbd3ec FB |
65 | }; |
66 | ||
67 | /* | |
68 | * Process a received ICMP message. | |
69 | */ | |
70 | void | |
511d2b14 | 71 | icmp_input(struct mbuf *m, int hlen) |
f0cbd3ec FB |
72 | { |
73 | register struct icmp *icp; | |
74 | register struct ip *ip=mtod(m, struct ip *); | |
75 | int icmplen=ip->ip_len; | |
76 | /* int code; */ | |
5fafdf24 | 77 | |
f0cbd3ec FB |
78 | DEBUG_CALL("icmp_input"); |
79 | DEBUG_ARG("m = %lx", (long )m); | |
80 | DEBUG_ARG("m_len = %d", m->m_len); | |
81 | ||
31a60e22 | 82 | STAT(icmpstat.icps_received++); |
5fafdf24 | 83 | |
f0cbd3ec FB |
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 */ | |
31a60e22 | 89 | STAT(icmpstat.icps_tooshort++); |
f0cbd3ec FB |
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)) { | |
31a60e22 | 99 | STAT(icmpstat.icps_checksum++); |
f0cbd3ec FB |
100 | goto freeit; |
101 | } | |
102 | m->m_len += hlen; | |
103 | m->m_data -= hlen; | |
3b46e624 | 104 | |
f0cbd3ec FB |
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 */ | |
8dbca8dd | 113 | if (ip->ip_dst.s_addr == alias_addr.s_addr) { |
f0cbd3ec FB |
114 | 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) { | |
5fafdf24 | 120 | DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n", |
f0cbd3ec FB |
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; | |
3b46e624 | 134 | |
f0cbd3ec FB |
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))); | |
5fafdf24 | 156 | icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno)); |
f0cbd3ec FB |
157 | udp_detach(so); |
158 | } | |
8dbca8dd | 159 | } /* if ip->ip_dst.s_addr == alias_addr.s_addr */ |
f0cbd3ec FB |
160 | 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: | |
31a60e22 | 169 | STAT(icmpstat.icps_notsupp++); |
f0cbd3ec FB |
170 | m_freem(m); |
171 | break; | |
3b46e624 | 172 | |
f0cbd3ec | 173 | default: |
31a60e22 | 174 | STAT(icmpstat.icps_badtype++); |
f0cbd3ec FB |
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. | |
5fafdf24 | 198 | * ICMP fragmentation is illegal. All machines must accept 576 bytes in one |
f0cbd3ec FB |
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 | |
7ccfb2eb BS |
204 | icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize, |
205 | const char *message) | |
f0cbd3ec FB |
206 | { |
207 | unsigned hlen, shlen, s_ip_len; | |
208 | register struct ip *ip; | |
209 | register struct icmp *icp; | |
210 | register struct mbuf *m; | |
211 | ||
212 | DEBUG_CALL("icmp_error"); | |
213 | DEBUG_ARG("msrc = %lx", (long )msrc); | |
214 | DEBUG_ARG("msrc_len = %d", msrc->m_len); | |
215 | ||
216 | if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error; | |
217 | ||
218 | /* check msrc */ | |
219 | if(!msrc) goto end_error; | |
220 | ip = mtod(msrc, struct ip *); | |
eb38c52c | 221 | #ifdef DEBUG |
f0cbd3ec FB |
222 | { char bufa[20], bufb[20]; |
223 | strcpy(bufa, inet_ntoa(ip->ip_src)); | |
224 | strcpy(bufb, inet_ntoa(ip->ip_dst)); | |
225 | DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb)); | |
226 | } | |
227 | #endif | |
228 | if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */ | |
229 | ||
230 | shlen=ip->ip_hl << 2; | |
231 | s_ip_len=ip->ip_len; | |
232 | if(ip->ip_p == IPPROTO_ICMP) { | |
233 | icp = (struct icmp *)((char *)ip + shlen); | |
234 | /* | |
235 | * Assume any unknown ICMP type is an error. This isn't | |
236 | * specified by the RFC, but think about it.. | |
237 | */ | |
238 | if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error; | |
239 | } | |
240 | ||
241 | /* make a copy */ | |
242 | if(!(m=m_get())) goto end_error; /* get mbuf */ | |
243 | { int new_m_size; | |
244 | new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN; | |
245 | if(new_m_size>m->m_size) m_inc(m, new_m_size); | |
246 | } | |
247 | memcpy(m->m_data, msrc->m_data, msrc->m_len); | |
248 | m->m_len = msrc->m_len; /* copy msrc to m */ | |
249 | ||
250 | /* make the header of the reply packet */ | |
251 | ip = mtod(m, struct ip *); | |
252 | hlen= sizeof(struct ip ); /* no options in reply */ | |
3b46e624 | 253 | |
f0cbd3ec | 254 | /* fill in icmp */ |
3b46e624 | 255 | m->m_data += hlen; |
f0cbd3ec FB |
256 | m->m_len -= hlen; |
257 | ||
258 | icp = mtod(m, struct icmp *); | |
259 | ||
260 | if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */ | |
261 | else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */ | |
262 | s_ip_len=ICMP_MAXDATALEN; | |
263 | ||
3b46e624 | 264 | m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */ |
f0cbd3ec FB |
265 | |
266 | /* min. size = 8+sizeof(struct ip)+8 */ | |
267 | ||
268 | icp->icmp_type = type; | |
269 | icp->icmp_code = code; | |
270 | icp->icmp_id = 0; | |
271 | icp->icmp_seq = 0; | |
272 | ||
273 | memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */ | |
274 | HTONS(icp->icmp_ip.ip_len); | |
275 | HTONS(icp->icmp_ip.ip_id); | |
276 | HTONS(icp->icmp_ip.ip_off); | |
277 | ||
eb38c52c | 278 | #ifdef DEBUG |
f0cbd3ec FB |
279 | if(message) { /* DEBUG : append message to ICMP packet */ |
280 | int message_len; | |
281 | char *cpnt; | |
282 | message_len=strlen(message); | |
283 | if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN; | |
284 | cpnt=(char *)m->m_data+m->m_len; | |
285 | memcpy(cpnt, message, message_len); | |
286 | m->m_len+=message_len; | |
287 | } | |
288 | #endif | |
289 | ||
290 | icp->icmp_cksum = 0; | |
291 | icp->icmp_cksum = cksum(m, m->m_len); | |
292 | ||
293 | m->m_data -= hlen; | |
294 | m->m_len += hlen; | |
295 | ||
296 | /* fill in ip */ | |
297 | ip->ip_hl = hlen >> 2; | |
298 | ip->ip_len = m->m_len; | |
3b46e624 | 299 | |
f0cbd3ec FB |
300 | ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */ |
301 | ||
302 | ip->ip_ttl = MAXTTL; | |
303 | ip->ip_p = IPPROTO_ICMP; | |
304 | ip->ip_dst = ip->ip_src; /* ip adresses */ | |
8dbca8dd | 305 | ip->ip_src = alias_addr; |
f0cbd3ec FB |
306 | |
307 | (void ) ip_output((struct socket *)NULL, m); | |
3b46e624 | 308 | |
31a60e22 | 309 | STAT(icmpstat.icps_reflect++); |
f0cbd3ec FB |
310 | |
311 | end_error: | |
312 | return; | |
313 | } | |
314 | #undef ICMP_MAXDATALEN | |
315 | ||
316 | /* | |
317 | * Reflect the ip packet back to the source | |
318 | */ | |
319 | void | |
511d2b14 | 320 | icmp_reflect(struct mbuf *m) |
f0cbd3ec FB |
321 | { |
322 | register struct ip *ip = mtod(m, struct ip *); | |
323 | int hlen = ip->ip_hl << 2; | |
324 | int optlen = hlen - sizeof(struct ip ); | |
325 | register struct icmp *icp; | |
326 | ||
327 | /* | |
328 | * Send an icmp packet back to the ip level, | |
329 | * after supplying a checksum. | |
330 | */ | |
331 | m->m_data += hlen; | |
332 | m->m_len -= hlen; | |
333 | icp = mtod(m, struct icmp *); | |
334 | ||
335 | icp->icmp_cksum = 0; | |
336 | icp->icmp_cksum = cksum(m, ip->ip_len - hlen); | |
337 | ||
338 | m->m_data -= hlen; | |
339 | m->m_len += hlen; | |
340 | ||
341 | /* fill in ip */ | |
342 | if (optlen > 0) { | |
343 | /* | |
344 | * Strip out original options by copying rest of first | |
345 | * mbuf's data back, and adjust the IP length. | |
346 | */ | |
347 | memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen, | |
348 | (unsigned )(m->m_len - hlen)); | |
349 | hlen -= optlen; | |
350 | ip->ip_hl = hlen >> 2; | |
351 | ip->ip_len -= optlen; | |
352 | m->m_len -= optlen; | |
353 | } | |
354 | ||
355 | ip->ip_ttl = MAXTTL; | |
356 | { /* swap */ | |
357 | struct in_addr icmp_dst; | |
358 | icmp_dst = ip->ip_dst; | |
359 | ip->ip_dst = ip->ip_src; | |
360 | ip->ip_src = icmp_dst; | |
361 | } | |
362 | ||
363 | (void ) ip_output((struct socket *)NULL, m); | |
364 | ||
31a60e22 | 365 | STAT(icmpstat.icps_reflect++); |
f0cbd3ec | 366 | } |