ip_icmp.c@ 22881

Last change on this file since 22881 was 22576, checked in by vboxsync, 15 years ago
NAT: logging, warnings
Property svn:eol-style set to `native`
File size: 21.4 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	#ifdef RT_OS_WINDOWS
45	# define ICMP_SEND_ECHO(event, routine, addr, data, datasize, ipopt) \
46	IcmpSendEcho2(pData->icmp_socket.sh, (event), NULL, NULL, (addr), (data), (datasize), \
47	(ipopt), pData->pvIcmpBuffer, pData->szIcmpBuffer, 1)
48	#endif /* RT_OS_WINDOWS */
49
50	/* The message sent when emulating PING */
51	/* Be nice and tell them it's just a psuedo-ping packet */
52	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
53
54	/* list of actions for icmp_error() on RX of an icmp message */
55	static const int icmp_flush[19] =
56	{
57	/* ECHO REPLY (0) */ 0,
58	1,
59	1,
60	/* DEST UNREACH (3) */ 1,
61	/* SOURCE QUENCH (4)*/ 1,
62	/* REDIRECT (5) */ 1,
63	1,
64	1,
65	/* ECHO (8) */ 0,
66	/* ROUTERADVERT (9) */ 1,
67	/* ROUTERSOLICIT (10) */ 1,
68	/* TIME EXCEEDED (11) */ 1,
69	/* PARAMETER PROBLEM (12) */ 1,
70	/* TIMESTAMP (13) */ 0,
71	/* TIMESTAMP REPLY (14) */ 0,
72	/* INFO (15) */ 0,
73	/* INFO REPLY (16) */ 0,
74	/* ADDR MASK (17) */ 0,
75	/* ADDR MASK REPLY (18) */ 0
76	};
77
78	int
79	icmp_init(PNATState pData)
80	{
81	pData->icmp_socket.so_type = IPPROTO_ICMP;
82	pData->icmp_socket.so_state = SS_ISFCONNECTED;
83	#ifndef RT_OS_WINDOWS
84	# ifndef RT_OS_DARWIN
85	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
86	# else /* !RT_OS_DARWIN */
87	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
88	# endif /* RT_OS_DARWIN */
89	if (pData->icmp_socket.s == -1)
90	{
91	int rc = RTErrConvertFromErrno(errno);
92	LogRel(("NAT: ICMP/ping not available (could open ICMP socket, error %Rrc)\n", rc));
93	return 1;
94	}
95	fd_nonblock(pData->icmp_socket.s);
96	NSOCK_INC();
97	#else /* RT_OS_WINDOWS */
98	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
99	if (pData->hmIcmpLibrary != NULL)
100	{
101	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
102	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
103	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
104	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
105	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
106	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
107	if (pData->pfGetAdaptersAddresses == NULL)
108	{
109	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll"));
110	}
111	}
112
113	if (pData->pfIcmpParseReplies == NULL)
114	{
115	if(pData->pfGetAdaptersAddresses == NULL)
116	FreeLibrary(pData->hmIcmpLibrary);
117	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
118	if (pData->hmIcmpLibrary == NULL)
119	{
120	LogRel(("NAT: Icmp.dll could not be loaded\n"));
121	return 1;
122	}
123	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
124	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
125	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
126	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
127	}
128	if (pData->pfIcmpParseReplies == NULL)
129	{
130	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
131	FreeLibrary(pData->hmIcmpLibrary);
132	return 1;
133	}
134	if (pData->pfIcmpCloseHandle == NULL)
135	{
136	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
137	FreeLibrary(pData->hmIcmpLibrary);
138	return 1;
139	}
140	pData->icmp_socket.sh = IcmpCreateFile();
141	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
142	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
143	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
144	#endif /* RT_OS_WINDOWS */
145	LIST_INIT(&pData->icmp_msg_head);
146	return 0;
147	}
148
149	/*
150	* ip here is ip header + 64bytes readed from ICMP packet
151	*/
152	struct icmp_msg *
153	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
154	{
155	struct mbuf *m0;
156	struct ip *ip0;
157	struct icmp icp, icp0;
158	struct icmp_msg *icm = NULL;
159	int found = 0;
160	struct udphdr *udp;
161	struct tcphdr *tcp;
162	struct socket *head_socket = NULL;
163	struct socket *last_socket = NULL;
164	struct socket *so = NULL;
165	struct in_addr laddr, faddr;
166	u_short lport, fport;
167
168	laddr.s_addr = ~0;
169	faddr.s_addr = ~0;
170
171	lport = ~0;
172	fport = ~0;
173
174
175	Log(("%s: processing (proto:%d)\n", __FUNCTION__, ip->ip_p));
176	switch (ip->ip_p)
177	{
178	case IPPROTO_ICMP:
179	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
180	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
181	{
182	m0 = icm->im_m;
183	ip0 = mtod(m0, struct ip *);
184	AssertRelease(ip0->ip_p == IPPROTO_ICMP);
185	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
186	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
187	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
188	&& icp->icmp_id == icp0->icmp_id
189	&& icp->icmp_seq == icp0->icmp_seq)
190	{
191	found = 1;
192	Log(("Have found %R[natsock]\n", icm->im_so));
193	break;
194	}
195	Log(("Have found nothing\n"));
196	}
197	break;
198
199	/*
200	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
201	* from which the IP package has been sent.
202	*/
203	case IPPROTO_UDP:
204	head_socket = &udb;
205	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
206	faddr.s_addr = ip->ip_dst.s_addr;
207	fport = udp->uh_dport;
208	laddr.s_addr = ip->ip_src.s_addr;
209	lport = udp->uh_sport;
210	last_socket = udp_last_so;
211	/* fall through */
212
213	case IPPROTO_TCP:
214	if (head_socket == NULL)
215	{
216	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
217	head_socket = &tcb; /* head_socket could be initialized with udb*/
218	faddr.s_addr = ip->ip_dst.s_addr;
219	fport = tcp->th_dport;
220	laddr.s_addr = ip->ip_src.s_addr;
221	lport = tcp->th_sport;
222	last_socket = tcp_last_so;
223	}
224	/* check last socket first */
225	if ( last_socket->so_faddr.s_addr == faddr.s_addr
226	&& last_socket->so_fport == fport
227	&& last_socket->so_hlport == lport)
228	{
229	found = 1;
230	so = last_socket;
231	goto sofound;
232	}
233	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
234	{
235	/* Should be reaplaced by hash here */
236	Log(("trying:%R[natsock] against %R[IP4]:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
237	if ( so->so_faddr.s_addr == faddr.s_addr
238	&& so->so_fport == fport
239	&& so->so_hlport == lport)
240	{
241	found = 1;
242	break;
243	}
244	}
245	break;
246
247	default:
248	LogRel(("%s:ICMP: unsupported protocol(%d)\n", __FUNCTION__, ip->ip_p));
249	}
250	sofound:
251	if (found == 1 && icm == NULL)
252	{
253	if (so->so_state == SS_NOFDREF)
254	{
255	/* socket is shutdowning we've already sent ICMP on it.*/
256	LogRel(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
257	return NULL;
258	}
259	icm = RTMemAlloc(sizeof(struct icmp_msg));
260	icm->im_m = so->so_m;
261	icm->im_so = so;
262	found = 1;
263	Log(("hit:%R[natsock]\n", so));
264	/*XXX: this storage not very long,
265	* better add flag if it should removed from lis
266	*/
267	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
268	return (icm);
269	}
270	if (found == 1)
271	return icm;
272
273	return NULL;
274	}
275
276	static int
277	icmp_attach(PNATState pData, struct mbuf *m)
278	{
279	struct icmp_msg *icm;
280	struct ip *ip;
281	ip = mtod(m, struct ip *);
282	Assert(ip->ip_p == IPPROTO_ICMP);
283	icm = RTMemAlloc(sizeof(struct icmp_msg));
284	icm->im_m = m;
285	icm->im_so = m->m_so;
286	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
287	return 0;
288	}
289
290	/*
291	* Process a received ICMP message.
292	*/
293	void
294	icmp_input(PNATState pData, struct mbuf *m, int hlen)
295	{
296	register struct icmp *icp;
297	register struct ip ip = mtod(m, struct ip );
298	int icmplen = ip->ip_len;
299	int status;
300	uint32_t dst;
301	#if !defined(RT_OS_WINDOWS)
302	int ttl;
303	#endif
304
305	/* int code; */
306
307	DEBUG_CALL("icmp_input");
308	DEBUG_ARG("m = %lx", (long )m);
309	DEBUG_ARG("m_len = %d", m ? m->m_len : 0);
310
311	icmpstat.icps_received++;
312
313	/*
314	* Locate icmp structure in mbuf, and check
315	* that its not corrupted and of at least minimum length.
316	*/
317	if (icmplen < ICMP_MINLEN)
318	{
319	/* min 8 bytes payload */
320	icmpstat.icps_tooshort++;
321	freeit:
322	m_freem(pData, m);
323	goto end_error;
324	}
325
326	m->m_len -= hlen;
327	m->m_data += hlen;
328	icp = mtod(m, struct icmp *);
329	if (cksum(m, icmplen))
330	{
331	icmpstat.icps_checksum++;
332	goto freeit;
333	}
334	m->m_len += hlen;
335	m->m_data -= hlen;
336
337	/* icmpstat.icps_inhist[icp->icmp_type]++; */
338	/* code = icp->icmp_code; */
339
340	DEBUG_ARG("icmp_type = %d", icp->icmp_type);
341	switch (icp->icmp_type)
342	{
343	case ICMP_ECHO:
344	ip->ip_len += hlen; /* since ip_input subtracts this */
345	dst = ip->ip_dst.s_addr;
346	if (dst == alias_addr.s_addr)
347	{
348	icp->icmp_type = ICMP_ECHOREPLY;
349	ip->ip_dst.s_addr = ip->ip_src.s_addr;
350	ip->ip_src.s_addr = dst;
351	icmp_reflect(pData, m);
352	}
353	else
354	{
355	struct sockaddr_in addr;
356	#ifdef RT_OS_WINDOWS
357	IP_OPTION_INFORMATION ipopt;
358	int error;
359	#endif
360	addr.sin_family = AF_INET;
361	if ((ip->ip_dst.s_addr & htonl(pData->netmask)) == special_addr.s_addr)
362	{
363	/* It's an alias */
364	switch (ntohl(ip->ip_dst.s_addr) & ~pData->netmask)
365	{
366	case CTL_DNS:
367	case CTL_ALIAS:
368	default:
369	addr.sin_addr = loopback_addr;
370	break;
371	}
372	}
373	else
374	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
375	#ifndef RT_OS_WINDOWS
376	if (pData->icmp_socket.s != -1)
377	{
378	m->m_so = &pData->icmp_socket;
379	icmp_attach(pData, m);
380	ttl = ip->ip_ttl;
381	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
382	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
383	(void *)&ttl, sizeof(ttl));
384	if (status < 0)
385	LogRel(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
386	strerror(errno)));
387	if (sendto(pData->icmp_socket.s, icp, icmplen, 0,
388	(struct sockaddr *)&addr, sizeof(addr)) == -1)
389	{
390	Log((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
391	errno, strerror(errno)));
392	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
393	}
394	}
395	else
396	{
397	/*
398	* We're freeing the ICMP message, which unable sent or process.
399	* That behavior described in rfc 793, we shouldn't notify sender about
400	* fail of processing it's ICMP packets
401	*/
402	m_free(pData, m);
403	return;
404	}
405	#else /* RT_OS_WINDOWS */
406	icmp_attach(pData, m);
407	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
408	pData->icmp_socket.so_icmp_id = icp->icmp_id;
409	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
410	m->m_so = &pData->icmp_socket;
411	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
412	ipopt.Ttl = ip->ip_ttl;
413	status = ICMP_SEND_ECHO(pData->phEvents[VBOX_ICMP_EVENT_INDEX], notify_slirp, addr.sin_addr.s_addr,
414	icp->icmp_data, icmplen - ICMP_MINLEN, &ipopt);
415	if (status == 0 && (error = GetLastError()) != ERROR_IO_PENDING)
416	{
417	error = GetLastError();
418	LogRel(("NAT: Error (%d) occurred while sending ICMP (", error));
419	switch (error)
420	{
421	case ERROR_INVALID_PARAMETER:
422	LogRel(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
423	break;
424	case ERROR_NOT_SUPPORTED:
425	LogRel(("operation is unsupported)\n"));
426	break;
427	case ERROR_NOT_ENOUGH_MEMORY:
428	LogRel(("OOM!!!)\n"));
429	break;
430	case IP_BUF_TOO_SMALL:
431	LogRel(("Buffer too small)\n"));
432	break;
433	default:
434	LogRel(("Other error!!!)\n"));
435	break;
436	}
437	}
438	#endif /* RT_OS_WINDOWS */
439	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
440	break;
441	case ICMP_UNREACH:
442	/* XXX? report error? close socket? */
443	case ICMP_TIMXCEED:
444	case ICMP_PARAMPROB:
445	case ICMP_SOURCEQUENCH:
446	case ICMP_TSTAMP:
447	case ICMP_MASKREQ:
448	case ICMP_REDIRECT:
449	icmpstat.icps_notsupp++;
450	m_freem(pData, m);
451	break;
452
453	default:
454	icmpstat.icps_badtype++;
455	m_freem(pData, m);
456	} /* switch */
457
458	end_error:
459	/* m is m_free()'d xor put in a socket xor or given to ip_send */
460	;
461	}
462
463
464	/*
465	* Send an ICMP message in response to a situation
466	*
467	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
468	* MUST NOT change this header information.
469	* MUST NOT reply to a multicast/broadcast IP address.
470	* MUST NOT reply to a multicast/broadcast MAC address.
471	* MUST reply to only the first fragment.
472	*/
473	/*
474	* Send ICMP_UNREACH back to the source regarding msrc.
475	* mbuf *msrc is used as a template, but is NOT m_free()'d.
476	* It is reported as the bad ip packet. The header should
477	* be fully correct and in host byte order.
478	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
479	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
480	*/
481
482	#define ICMP_MAXDATALEN (IP_MSS-28)
483	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
484	{
485	unsigned hlen, shlen, s_ip_len;
486	register struct ip *ip;
487	register struct icmp *icp;
488	register struct mbuf *m;
489
490	DEBUG_CALL("icmp_error");
491	DEBUG_ARG("msrc = %lx", (long )msrc);
492	DEBUG_ARG("msrc_len = %d", msrc ? msrc->m_len : 0);
493
494	if (type!=ICMP_UNREACH && type!=ICMP_TIMXCEED)
495	goto end_error;
496
497	/* check msrc */
498	if (!msrc)
499	goto end_error;
500
501	ip = mtod(msrc, struct ip *);
502	#if DEBUG
503	{
504	char bufa[20], bufb[20];
505	strcpy(bufa, inet_ntoa(ip->ip_src));
506	strcpy(bufb, inet_ntoa(ip->ip_dst));
507	DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
508	}
509	#endif
510	if (ip->ip_off & IP_OFFMASK)
511	goto end_error; /* Only reply to fragment 0 */
512
513	shlen = ip->ip_hl << 2;
514	s_ip_len = ip->ip_len;
515	if (ip->ip_p == IPPROTO_ICMP)
516	{
517	icp = (struct icmp )((char )ip + shlen);
518	/*
519	* Assume any unknown ICMP type is an error. This isn't
520	* specified by the RFC, but think about it..
521	*/
522	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
523	goto end_error;
524	}
525
526	/* make a copy */
527	if (!(m = m_get(pData)))
528	goto end_error; /* get mbuf */
529	{
530	int new_m_size;
531	m->m_data += if_maxlinkhdr;
532	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
533	if (new_m_size > m->m_size)
534	m_inc(m, new_m_size);
535	}
536
537	memcpy(m->m_data, msrc->m_data, msrc->m_len);
538	m->m_len = msrc->m_len; /* copy msrc to m */
539
540	/* make the header of the reply packet */
541	ip = mtod(m, struct ip *);
542	hlen = sizeof(struct ip ); /* no options in reply */
543
544	/* fill in icmp */
545	m->m_data += hlen;
546	m->m_len -= hlen;
547
548	icp = mtod(m, struct icmp *);
549
550	if (minsize)
551	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
552	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
553	s_ip_len = ICMP_MAXDATALEN;
554
555	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
556
557	/* min. size = 8+sizeof(struct ip)+8 */
558
559	icp->icmp_type = type;
560	icp->icmp_code = code;
561	icp->icmp_id = 0;
562	icp->icmp_seq = 0;
563
564	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
565	HTONS(icp->icmp_ip.ip_len);
566	HTONS(icp->icmp_ip.ip_id);
567	HTONS(icp->icmp_ip.ip_off);
568
569	#if DEBUG
570	if (message)
571	{
572	/* DEBUG : append message to ICMP packet */
573	int message_len;
574	char *cpnt;
575	message_len = strlen(message);
576	if (message_len > ICMP_MAXDATALEN)
577	message_len = ICMP_MAXDATALEN;
578	cpnt = (char *)m->m_data+m->m_len;
579	memcpy(cpnt, message, message_len);
580	m->m_len += message_len;
581	}
582	#endif
583
584	icp->icmp_cksum = 0;
585	icp->icmp_cksum = cksum(m, m->m_len);
586
587	m->m_data -= hlen;
588	m->m_len += hlen;
589
590	/* fill in ip */
591	ip->ip_hl = hlen >> 2;
592	ip->ip_len = m->m_len;
593
594	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
595
596	ip->ip_ttl = MAXTTL;
597	ip->ip_p = IPPROTO_ICMP;
598	ip->ip_dst = ip->ip_src; /* ip adresses */
599	ip->ip_src = alias_addr;
600
601	(void ) ip_output(pData, (struct socket *)NULL, m);
602
603	icmpstat.icps_reflect++;
604
605	return;
606
607	end_error:
608	LogRel(("NAT: error occurred while sending ICMP error message \n"));
609	}
610	#undef ICMP_MAXDATALEN
611
612	/*
613	* Reflect the ip packet back to the source
614	*/
615	void
616	icmp_reflect(PNATState pData, struct mbuf *m)
617	{
618	register struct ip ip = mtod(m, struct ip );
619	int hlen = ip->ip_hl << 2;
620	int optlen = hlen - sizeof(struct ip );
621	register struct icmp *icp;
622
623	/*
624	* Send an icmp packet back to the ip level,
625	* after supplying a checksum.
626	*/
627	m->m_data += hlen;
628	m->m_len -= hlen;
629	icp = mtod(m, struct icmp *);
630
631	icp->icmp_cksum = 0;
632	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
633
634	m->m_data -= hlen;
635	m->m_len += hlen;
636
637	(void ) ip_output(pData, (struct socket *)NULL, m);
638
639	icmpstat.icps_reflect++;
640	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 22881

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