ip_icmp.c@ 15312

Last change on this file since 15312 was 15312, checked in by vboxsync, 16 years ago
icmp:slirp: correcting switch
Property svn:eol-style set to `native`
File size: 21.6 KB

Line
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	#ifdef RT_OS_WINDOWS
40	#include <Icmpapi.h>
41	#include <Iphlpapi.h>
42	#endif
43
44
45	/* The message sent when emulating PING */
46	/* Be nice and tell them it's just a psuedo-ping packet */
47	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
48
49	/* list of actions for icmp_error() on RX of an icmp message */
50	static const int icmp_flush[19] =
51	{
52	/* ECHO REPLY (0) */ 0,
53	1,
54	1,
55	/* DEST UNREACH (3) */ 1,
56	/* SOURCE QUENCH (4)*/ 1,
57	/* REDIRECT (5) */ 1,
58	1,
59	1,
60	/* ECHO (8) */ 0,
61	/* ROUTERADVERT (9) */ 1,
62	/* ROUTERSOLICIT (10) */ 1,
63	/* TIME EXCEEDED (11) */ 1,
64	/* PARAMETER PROBLEM (12) */ 1,
65	/* TIMESTAMP (13) */ 0,
66	/* TIMESTAMP REPLY (14) */ 0,
67	/* INFO (15) */ 0,
68	/* INFO REPLY (16) */ 0,
69	/* ADDR MASK (17) */ 0,
70	/* ADDR MASK REPLY (18) */ 0
71	};
72
73	#ifdef VBOX_WITH_SLIRP_ICMP
74	int
75	icmp_init(PNATState pData)
76	{
77	pData->icmp_socket.so_type = IPPROTO_ICMP;
78	pData->icmp_socket.so_state = SS_ISFCONNECTED;
79	#ifndef RT_OS_WINDOWS
80	# ifndef RT_OS_DARWIN
81	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
82	# else /* !RT_OS_DARWIN */
83	pData->icmp_socket.s = socket(PF_INET, SOCK_DGRAM, IPPROTO_ICMP);
84	# endif /* RT_OS_DARWIN */
85	if (pData->icmp_socket.s == -1)
86	{
87	int rc = RTErrConvertFromErrno(errno);
88	LogRel(("NAT: ICMP/ping not available (could open ICMP socket, error %Rrc)\n", rc));
89	return 1;
90	}
91	#else /* RT_OS_WINDOWS */
92	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
93	if (pData->hmIcmpLibrary != NULL)
94	{
95	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
96	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
97	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
98	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
99	}
100	if (pData->pfIcmpParseReplies == NULL)
101	{
102	FreeLibrary(pData->hmIcmpLibrary);
103	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
104	if (pData->hmIcmpLibrary == NULL)
105	{
106	LogRel(("NAT: Icmp.dll could not be loaded\n"));
107	return 1;
108	}
109	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
110	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
111	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
112	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
113	}
114	if (pData->pfIcmpParseReplies == NULL)
115	{
116	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
117	FreeLibrary(pData->hmIcmpLibrary);
118	return 1;
119	}
120	if (pData->pfIcmpCloseHandle == NULL)
121	{
122	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
123	FreeLibrary(pData->hmIcmpLibrary);
124	return 1;
125	}
126	pData->icmp_socket.sh = IcmpCreateFile();
127	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
128	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
129	pData->pvIcmpBuffer = malloc(pData->szIcmpBuffer);
130	#endif /* RT_OS_WINDOWS */
131	LIST_INIT(&pData->icmp_msg_head);
132	return 0;
133	}
134
135	/*
136	* ip here is ip header + 64bytes readed from ICMP packet
137	*/
138	struct icmp_msg *
139	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
140	{
141	struct mbuf *m0;
142	struct ip *ip0;
143	struct icmp icp, icp0;
144	struct icmp_msg *icm = NULL;
145	int found = 0;
146	struct udphdr *udp;
147	struct tcphdr *tcp;
148	struct socket head_socket, so;
149	struct in_addr laddr, faddr;
150	u_int lport, fport;
151
152	laddr.s_addr = ~0;
153	faddr.s_addr = ~0;
154
155	lport = ~0;
156	fport = ~0;
157
158
159	switch (ip->ip_p)
160	{
161	case IPPROTO_ICMP:
162	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
163	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
164	{
165	m0 = icm->im_m;
166	ip0 = mtod(m0, struct ip *);
167	AssertRelease(ip0->ip_p == IPPROTO_ICMP);
168	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
169	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
170	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
171	&& icp->icmp_id == icp0->icmp_id
172	&& icp->icmp_seq == icp->icmp_seq)
173	{
174	found = 1;
175	break;
176	}
177	}
178	break;
179
180	/*
181	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
182	* from which the IP package has been sent.
183	*/
184	case IPPROTO_UDP:
185	head_socket = &udb;
186	udp = (struct udphdr )((char )ip + (ip->ip_hl >> 2));
187	faddr.s_addr = ip->ip_dst.s_addr;
188	fport = udp->uh_dport;
189	laddr.s_addr = ip->ip_src.s_addr;
190	lport = udp->uh_sport;
191	/* fall through */
192
193	case IPPROTO_TCP:
194	if (head_socket == NULL)
195	{
196	tcp = (struct tcphdr )((char )ip + (ip->ip_hl >> 2));
197	head_socket = &tcb; /* head_socket could be initialized with udb*/
198	faddr.s_addr = ip->ip_dst.s_addr;
199	fport = tcp->th_dport;
200	laddr.s_addr = ip->ip_src.s_addr;
201	lport = tcp->th_sport;
202	}
203	for (so = head_socket; so != head_socket; so = so->so_next)
204	{
205	/* Should be reaplaced by hash here */
206	if ( so->so_faddr.s_addr == faddr.s_addr
207	&& so->so_fport == fport
208	&& so->so_hladdr.s_addr == laddr.s_addr
209	&& so->so_hlport == lport)
210	{
211	icm = malloc(sizeof(struct icmp_msg));
212	icm->im_m = so->so_m;
213	found = 1;
214	break;
215	}
216	}
217	break;
218
219	default:
220	LogRel(("%s:ICMP: unsupported protocol(%d)\n", __FUNCTION__, ip->ip_p));
221	}
222	if (found == 1)
223	return icm;
224
225	return NULL;
226	}
227
228	static int
229	icmp_attach(PNATState pData, struct mbuf *m)
230	{
231	struct icmp_msg *icm;
232	struct ip *ip;
233	ip = mtod(m, struct ip *);
234	Assert(ip->ip_p == IPPROTO_ICMP);
235	icm = malloc(sizeof(struct icmp_msg));
236	icm->im_m = m;
237	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
238	return 0;
239	}
240	#endif /* VBOX_WITH_SLIRP_ICMP */
241
242	/*
243	* Process a received ICMP message.
244	*/
245	void
246	icmp_input(PNATState pData, struct mbuf *m, int hlen)
247	{
248	register struct icmp *icp;
249	register struct ip ip = mtod(m, struct ip );
250	int icmplen = ip->ip_len;
251	int status;
252	uint32_t dst;
253
254	/* int code; */
255
256	DEBUG_CALL("icmp_input");
257	DEBUG_ARG("m = %lx", (long )m);
258	DEBUG_ARG("m_len = %d", m->m_len);
259
260	icmpstat.icps_received++;
261
262	/*
263	* Locate icmp structure in mbuf, and check
264	* that its not corrupted and of at least minimum length.
265	*/
266	if (icmplen < ICMP_MINLEN)
267	{
268	/* min 8 bytes payload */
269	icmpstat.icps_tooshort++;
270	freeit:
271	m_freem(pData, m);
272	goto end_error;
273	}
274
275	m->m_len -= hlen;
276	m->m_data += hlen;
277	icp = mtod(m, struct icmp *);
278	if (cksum(m, icmplen))
279	{
280	icmpstat.icps_checksum++;
281	goto freeit;
282	}
283	m->m_len += hlen;
284	m->m_data -= hlen;
285
286	/* icmpstat.icps_inhist[icp->icmp_type]++; */
287	/* code = icp->icmp_code; */
288
289	DEBUG_ARG("icmp_type = %d", icp->icmp_type);
290	switch (icp->icmp_type)
291	{
292	case ICMP_ECHO:
293	#ifndef VBOX_WITH_SLIRP_ICMP
294	icp->icmp_type = ICMP_ECHOREPLY;
295	#endif /* !VBOX_WITH_SLIRP_ICMP */
296
297	ip->ip_len += hlen; /* since ip_input subtracts this */
298	dst = ip->ip_dst.s_addr;
299	if (dst == alias_addr.s_addr)
300	{
301	#ifdef VBOX_WITH_SLIRP_ICMP
302	icp->icmp_type = ICMP_ECHOREPLY;
303	ip->ip_dst.s_addr = ip->ip_src.s_addr;
304	ip->ip_src.s_addr = dst;
305	#endif /* VBOX_WITH_SLIRP_ICMP */
306	icmp_reflect(pData, m);
307	}
308	else
309	{
310	struct socket *so;
311	struct sockaddr_in addr;
312	#ifndef VBOX_WITH_SLIRP_ICMP
313	if ((so = socreate()) == NULL)
314	goto freeit;
315	if (udp_attach(pData, so) == -1)
316	{
317	DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n",
318	errno,strerror(errno)));
319	sofree(pData, so);
320	m_free(pData, m);
321	goto end_error;
322	}
323	so->so_m = m;
324	so->so_faddr = ip->ip_dst;
325	so->so_fport = htons(7);
326	so->so_laddr = ip->ip_src;
327	so->so_lport = htons(9);
328	so->so_iptos = ip->ip_tos;
329	so->so_type = IPPROTO_ICMP;
330	so->so_state = SS_ISFCONNECTED;
331
332	addr.sin_family = AF_INET;
333	if ((so->so_faddr.s_addr & htonl(pData->netmask)) == special_addr.s_addr)
334	{
335	/* It's an alias */
336	switch (ntohl(so->so_faddr.s_addr) & ~pData->netmask)
337	{
338	case CTL_DNS:
339	addr.sin_addr = dns_addr;
340	break;
341	case CTL_ALIAS:
342	default:
343	addr.sin_addr = loopback_addr;
344	break;
345	}
346	}
347	else
348	addr.sin_addr = so->so_faddr;
349	addr.sin_port = so->so_fport;
350	if (sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0,
351	(struct sockaddr *)&addr, sizeof(addr)) == -1)
352	{
353	DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
354	errno,strerror(errno)));
355	icmp_error(pData, m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
356	udp_detach(pData, so);
357	}
358	#else /* VBOX_WITH_SLIRP_ICMP */
359	# ifdef RT_OS_WINDOWS
360	IP_OPTION_INFORMATION ipopt;
361	int error;
362	# endif
363	addr.sin_family = AF_INET;
364	if ((ip->ip_dst.s_addr & htonl(pData->netmask)) == special_addr.s_addr)
365	{
366	/* It's an alias */
367	switch(ntohl(ip->ip_dst.s_addr) & ~pData->netmask)
368	{
369	case CTL_DNS:
370	addr.sin_addr = dns_addr;
371	break;
372	case CTL_ALIAS:
373	default:
374	addr.sin_addr = loopback_addr;
375	break;
376	}
377	}
378	else
379	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
380	icmp_attach(pData, m);
381	/* Send the packet */
382	# ifndef RT_OS_WINDOWS
383	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL, (void *)&ip->ip_ttl, sizeof(ip->ip_ttl));
384	if (status < 0)
385	{
386	LogRel(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n", strerror(errno)));
387	}
388	if (sendto(pData->icmp_socket.s, icp, icmplen, 0,
389	(struct sockaddr *)&addr, sizeof(addr)) == -1)
390	{
391	DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
392	errno,strerror(errno)));
393	icmp_error(pData, m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
394	m_free(pData, m);
395	}
396	# else /* RT_OS_WINDOWS */
397	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
398	pData->icmp_socket.so_icmp_id = icp->icmp_id;
399	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
400	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
401	ipopt.Ttl = ip->ip_ttl;
402	status = IcmpSendEcho2(pData->icmp_socket.sh, pData->phEvents[VBOX_ICMP_EVENT_INDEX],
403	NULL, NULL, addr.sin_addr.s_addr, icp->icmp_data,
404	icmplen - offsetof(struct icmp, icmp_data) , &ipopt,
405	pData->pvIcmpBuffer, pData->szIcmpBuffer, 1);
406	if (status == 0 && (error = GetLastError()) != ERROR_IO_PENDING)
407	{
408	error = GetLastError();
409	LogRel(("NAT: Error (%d) occurred while sending ICMP (", error));
410	switch (error)
411	{
412	case ERROR_INVALID_PARAMETER:
413	LogRel(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
414	break;
415	case ERROR_NOT_SUPPORTED:
416	LogRel(("operation is unsupported)\n"));
417	break;
418	case ERROR_NOT_ENOUGH_MEMORY:
419	LogRel(("OOM!!!)\n"));
420	break;
421	case IP_BUF_TOO_SMALL:
422	LogRel(("Buffer too small)\n"));
423	break;
424	default:
425	LogRel(("Other error!!!)\n"));
426	break;
427	}
428	}
429	# endif /* RT_OS_WINDOWS */
430	#endif /* VBOX_WITH_SLIRP_ICMP */
431	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
432	break;
433	case ICMP_UNREACH:
434	/* XXX? report error? close socket? */
435	case ICMP_TIMXCEED:
436	case ICMP_PARAMPROB:
437	case ICMP_SOURCEQUENCH:
438	case ICMP_TSTAMP:
439	case ICMP_MASKREQ:
440	case ICMP_REDIRECT:
441	icmpstat.icps_notsupp++;
442	m_freem(pData, m);
443	break;
444
445	default:
446	icmpstat.icps_badtype++;
447	m_freem(pData, m);
448	} /* switch */
449
450	end_error:
451	/* m is m_free()'d xor put in a socket xor or given to ip_send */
452	;
453	}
454
455
456	/*
457	* Send an ICMP message in response to a situation
458	*
459	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
460	* MUST NOT change this header information.
461	* MUST NOT reply to a multicast/broadcast IP address.
462	* MUST NOT reply to a multicast/broadcast MAC address.
463	* MUST reply to only the first fragment.
464	*/
465	/*
466	* Send ICMP_UNREACH back to the source regarding msrc.
467	* mbuf *msrc is used as a template, but is NOT m_free()'d.
468	* It is reported as the bad ip packet. The header should
469	* be fully correct and in host byte order.
470	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
471	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
472	*/
473
474	#define ICMP_MAXDATALEN (IP_MSS-28)
475	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
476	{
477	unsigned hlen, shlen, s_ip_len;
478	register struct ip *ip;
479	register struct icmp *icp;
480	register struct mbuf *m;
481
482	DEBUG_CALL("icmp_error");
483	DEBUG_ARG("msrc = %lx", (long )msrc);
484	DEBUG_ARG("msrc_len = %d", msrc->m_len);
485
486	if (type!=ICMP_UNREACH && type!=ICMP_TIMXCEED)
487	goto end_error;
488
489	/* check msrc */
490	if (!msrc)
491	goto end_error;
492
493	ip = mtod(msrc, struct ip *);
494	#if DEBUG
495	{
496	char bufa[20], bufb[20];
497	strcpy(bufa, inet_ntoa(ip->ip_src));
498	strcpy(bufb, inet_ntoa(ip->ip_dst));
499	DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
500	}
501	#endif
502	if (ip->ip_off & IP_OFFMASK)
503	goto end_error; /* Only reply to fragment 0 */
504
505	shlen = ip->ip_hl << 2;
506	s_ip_len = ip->ip_len;
507	if (ip->ip_p == IPPROTO_ICMP)
508	{
509	icp = (struct icmp )((char )ip + shlen);
510	/*
511	* Assume any unknown ICMP type is an error. This isn't
512	* specified by the RFC, but think about it..
513	*/
514	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
515	goto end_error;
516	}
517
518	/* make a copy */
519	if (!(m = m_get(pData)))
520	goto end_error; /* get mbuf */
521	{
522	int new_m_size;
523	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
524	if (new_m_size>m->m_size)
525	m_inc(m, new_m_size);
526	}
527	memcpy(m->m_data, msrc->m_data, msrc->m_len);
528	m->m_len = msrc->m_len; /* copy msrc to m */
529
530	/* make the header of the reply packet */
531	ip = mtod(m, struct ip *);
532	hlen = sizeof(struct ip ); /* no options in reply */
533
534	/* fill in icmp */
535	m->m_data += hlen;
536	m->m_len -= hlen;
537
538	icp = mtod(m, struct icmp *);
539
540	if (minsize)
541	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
542	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
543	s_ip_len = ICMP_MAXDATALEN;
544
545	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
546
547	/* min. size = 8+sizeof(struct ip)+8 */
548
549	icp->icmp_type = type;
550	icp->icmp_code = code;
551	icp->icmp_id = 0;
552	icp->icmp_seq = 0;
553
554	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
555	HTONS(icp->icmp_ip.ip_len);
556	HTONS(icp->icmp_ip.ip_id);
557	HTONS(icp->icmp_ip.ip_off);
558
559	#if DEBUG
560	if (message)
561	{
562	/* DEBUG : append message to ICMP packet */
563	int message_len;
564	char *cpnt;
565	message_len = strlen(message);
566	if (message_len > ICMP_MAXDATALEN)
567	message_len = ICMP_MAXDATALEN;
568	cpnt = (char *)m->m_data+m->m_len;
569	memcpy(cpnt, message, message_len);
570	m->m_len += message_len;
571	}
572	#endif
573
574	icp->icmp_cksum = 0;
575	icp->icmp_cksum = cksum(m, m->m_len);
576
577	m->m_data -= hlen;
578	m->m_len += hlen;
579
580	/* fill in ip */
581	ip->ip_hl = hlen >> 2;
582	ip->ip_len = m->m_len;
583
584	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
585
586	ip->ip_ttl = MAXTTL;
587	ip->ip_p = IPPROTO_ICMP;
588	ip->ip_dst = ip->ip_src; /* ip adresses */
589	ip->ip_src = alias_addr;
590
591	(void ) ip_output(pData, (struct socket *)NULL, m);
592
593	icmpstat.icps_reflect++;
594
595	end_error:
596	;
597	}
598	#undef ICMP_MAXDATALEN
599
600	/*
601	* Reflect the ip packet back to the source
602	*/
603	void
604	icmp_reflect(PNATState pData, struct mbuf *m)
605	{
606	register struct ip ip = mtod(m, struct ip );
607	int hlen = ip->ip_hl << 2;
608	int optlen = hlen - sizeof(struct ip );
609	register struct icmp *icp;
610
611	/*
612	* Send an icmp packet back to the ip level,
613	* after supplying a checksum.
614	*/
615	m->m_data += hlen;
616	m->m_len -= hlen;
617	icp = mtod(m, struct icmp *);
618
619	icp->icmp_cksum = 0;
620	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
621
622	m->m_data -= hlen;
623	m->m_len += hlen;
624
625	#ifndef VBOX_WITH_SLIRP_ICMP
626	/* fill in ip */
627	if (optlen > 0)
628	{
629	/*
630	* Strip out original options by copying rest of first
631	* mbuf's data back, and adjust the IP length.
632	*/
633	memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen,
634	(unsigned )(m->m_len - hlen));
635	hlen -= optlen;
636	ip->ip_hl = hlen >> 2;
637	ip->ip_len -= optlen;
638	m->m_len -= optlen;
639	}
640	ip->ip_ttl = MAXTTL;
641	{
642	/* swap */
643	struct in_addr icmp_dst;
644	icmp_dst = ip->ip_dst;
645	ip->ip_dst = ip->ip_src;
646	ip->ip_src = icmp_dst;
647	}
648	#endif /* !VBOX_WITH_SLIRP_ICMP */
649
650	(void ) ip_output(pData, (struct socket *)NULL, m);
651
652	icmpstat.icps_reflect++;
653	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 15312

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