ip_icmp.c@ 38927

Last change on this file since 38927 was 38927, checked in by vboxsync, 13 years ago
NAT: Don't let ICMP cache to grow without limitations.
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1	/* $Id: ip_icmp.c 38927 2011-10-01 03:28:49Z vboxsync $ */
2	/** @file
3	* NAT - IP/ICMP handling.
4	*/
5
6	/*
7	* Copyright (C) 2006-2010 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18	/*
19	* This code is based on:
20	*
21	* Copyright (c) 1982, 1986, 1988, 1993
22	* The Regents of the University of California. All rights reserved.
23	*
24	* Redistribution and use in source and binary forms, with or without
25	* modification, are permitted provided that the following conditions
26	* are met:
27	* 1. Redistributions of source code must retain the above copyright
28	* notice, this list of conditions and the following disclaimer.
29	* 2. Redistributions in binary form must reproduce the above copyright
30	* notice, this list of conditions and the following disclaimer in the
31	* documentation and/or other materials provided with the distribution.
32	* 3. All advertising materials mentioning features or use of this software
33	* must display the following acknowledgement:
34	* This product includes software developed by the University of
35	* California, Berkeley and its contributors.
36	* 4. Neither the name of the University nor the names of its contributors
37	* may be used to endorse or promote products derived from this software
38	* without specific prior written permission.
39	*
40	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
41	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
44	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50	* SUCH DAMAGE.
51	*
52	* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
53	* ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
54	*/
55
56	#include "slirp.h"
57	#include "ip_icmp.h"
58	#ifdef RT_OS_WINDOWS
59	#include <Icmpapi.h>
60	#include <Iphlpapi.h>
61	#endif
62
63	/* The message sent when emulating PING */
64	/* Be nice and tell them it's just a psuedo-ping packet */
65	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
66
67	/* list of actions for icmp_error() on RX of an icmp message */
68	static const int icmp_flush[19] =
69	{
70	/* ECHO REPLY (0) */ 0,
71	1,
72	1,
73	/* DEST UNREACH (3) */ 1,
74	/* SOURCE QUENCH (4)*/ 1,
75	/* REDIRECT (5) */ 1,
76	1,
77	1,
78	/* ECHO (8) */ 0,
79	/* ROUTERADVERT (9) */ 1,
80	/* ROUTERSOLICIT (10) */ 1,
81	/* TIME EXCEEDED (11) */ 1,
82	/* PARAMETER PROBLEM (12) */ 1,
83	/* TIMESTAMP (13) */ 0,
84	/* TIMESTAMP REPLY (14) */ 0,
85	/* INFO (15) */ 0,
86	/* INFO REPLY (16) */ 0,
87	/* ADDR MASK (17) */ 0,
88	/* ADDR MASK REPLY (18) */ 0
89	};
90
91	static int icmp_cache_count(PNATState pData);
92	static void icmp_cache_clean(PNATState pData, int iEntries);
93
94	int
95	icmp_init(PNATState pData)
96	{
97	pData->icmp_socket.so_type = IPPROTO_ICMP;
98	pData->icmp_socket.so_state = SS_ISFCONNECTED;
99	#ifndef RT_OS_WINDOWS
100	# ifndef RT_OS_DARWIN
101	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
102	# else /* !RT_OS_DARWIN */
103	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
104	# endif /* RT_OS_DARWIN */
105	if (pData->icmp_socket.s == -1)
106	{
107	int rc = RTErrConvertFromErrno(errno);
108	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
109	return 1;
110	}
111	fd_nonblock(pData->icmp_socket.s);
112	NSOCK_INC();
113	#else /* RT_OS_WINDOWS */
114	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
115	if (pData->hmIcmpLibrary != NULL)
116	{
117	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
118	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
119	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
120	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
121	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
122	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
123	if (pData->pfGetAdaptersAddresses == NULL)
124	{
125	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll\n"));
126	}
127	}
128
129	if (pData->pfIcmpParseReplies == NULL)
130	{
131	if(pData->pfGetAdaptersAddresses == NULL)
132	FreeLibrary(pData->hmIcmpLibrary);
133	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
134	if (pData->hmIcmpLibrary == NULL)
135	{
136	LogRel(("NAT: Icmp.dll could not be loaded\n"));
137	return 1;
138	}
139	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
140	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
141	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
142	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
143	}
144	if (pData->pfIcmpParseReplies == NULL)
145	{
146	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
147	FreeLibrary(pData->hmIcmpLibrary);
148	return 1;
149	}
150	if (pData->pfIcmpCloseHandle == NULL)
151	{
152	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
153	FreeLibrary(pData->hmIcmpLibrary);
154	return 1;
155	}
156	pData->icmp_socket.sh = IcmpCreateFile();
157	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
158	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
159	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
160	#endif /* RT_OS_WINDOWS */
161	LIST_INIT(&pData->icmp_msg_head);
162	return 0;
163	}
164
165	/*
166	* ip here is ip header + 64bytes readed from ICMP packet
167	*/
168	struct icmp_msg *
169	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
170	{
171	struct mbuf *m0;
172	struct ip *ip0;
173	struct icmp icp, icp0;
174	struct icmp_msg *icm = NULL;
175	int found = 0;
176	struct udphdr *udp;
177	struct tcphdr *tcp;
178	struct socket *head_socket = NULL;
179	struct socket *last_socket = NULL;
180	struct socket *so = NULL;
181	struct in_addr laddr, faddr;
182	u_short lport, fport;
183
184	laddr.s_addr = ~0;
185	faddr.s_addr = ~0;
186
187	lport = ~0;
188	fport = ~0;
189
190
191	LogFlowFunc(("ENTER: ip->ip_p:%d\n", ip->ip_p));
192	switch (ip->ip_p)
193	{
194	case IPPROTO_ICMP:
195	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
196	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
197	{
198	m0 = icm->im_m;
199	ip0 = mtod(m0, struct ip *);
200	if (ip0->ip_p != IPPROTO_ICMP)
201	{
202	/* try next item */
203	continue;
204	}
205	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
206	/*
207	* IP could pointer to ICMP_REPLY datagram (1)
208	* or pointer IP header in ICMP payload in case of
209	* ICMP_TIMXCEED or ICMP_UNREACH (2)
210	*
211	* if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
212	* IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
213	*
214	* if (2) then check that payload ICMP has got type ICMP_ECHO and
215	* IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
216	* one was sent.
217	*/
218	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
219	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
220	&& icp->icmp_id == icp0->icmp_id
221	&& icp->icmp_seq == icp0->icmp_seq)
222	{
223	found = 1;
224	Log(("Have found %R[natsock]\n", icm->im_so));
225	break;
226	}
227	Log(("Have found nothing\n"));
228	}
229	break;
230
231	/*
232	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
233	* from which the IP package has been sent.
234	*/
235	case IPPROTO_UDP:
236	head_socket = &udb;
237	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
238	faddr.s_addr = ip->ip_dst.s_addr;
239	fport = udp->uh_dport;
240	laddr.s_addr = ip->ip_src.s_addr;
241	lport = udp->uh_sport;
242	last_socket = udp_last_so;
243	/* fall through */
244
245	case IPPROTO_TCP:
246	if (head_socket == NULL)
247	{
248	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
249	head_socket = &tcb; /* head_socket could be initialized with udb*/
250	faddr.s_addr = ip->ip_dst.s_addr;
251	fport = tcp->th_dport;
252	laddr.s_addr = ip->ip_src.s_addr;
253	lport = tcp->th_sport;
254	last_socket = tcp_last_so;
255	}
256	/* check last socket first */
257	if ( last_socket->so_faddr.s_addr == faddr.s_addr
258	&& last_socket->so_fport == fport
259	&& last_socket->so_hlport == lport)
260	{
261	found = 1;
262	so = last_socket;
263	goto sofound;
264	}
265	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
266	{
267	/* Should be reaplaced by hash here */
268	Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
269	if ( so->so_faddr.s_addr == faddr.s_addr
270	&& so->so_fport == fport
271	&& so->so_hlport == lport)
272	{
273	found = 1;
274	break;
275	}
276	}
277	break;
278
279	default:
280	Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
281	}
282	sofound:
283	if (found == 1 && icm == NULL)
284	{
285	if (so->so_state == SS_NOFDREF)
286	{
287	/* socket is shutdowning we've already sent ICMP on it.*/
288	Log(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
289	return NULL;
290	}
291	icm = RTMemAlloc(sizeof(struct icmp_msg));
292	icm->im_m = so->so_m;
293	icm->im_so = so;
294	found = 1;
295	Log(("hit:%R[natsock]\n", so));
296	/*XXX: this storage not very long,
297	* better add flag if it should removed from lis
298	*/
299	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
300	LogFlowFunc(("LEAVE: icm:%p\n", icm));
301	return (icm);
302	}
303	if (found == 1)
304	{
305	LogFlowFunc(("LEAVE: icm:%p\n", icm));
306	return icm;
307	}
308
309	LogFlowFunc(("LEAVE: NULL\n"));
310	return NULL;
311	}
312
313	static int icmp_cache_count(PNATState pData)
314	{
315	int iIcmpCount = 0;
316	struct icmp_msg *icm = NULL;
317	LogFlowFuncEnter();
318	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
319	iIcmpCount++;
320	LogFlowFunc(("LEAVE: %d\n", iIcmpCount));
321	return iIcmpCount;
322	}
323	/**
324	* iEntries how many entries to leave, if iEntries < 0, clean all
325	*/
326	static void icmp_cache_clean(PNATState pData, int iEntries)
327	{
328	int iIcmpCount = 0;
329	struct icmp_msg *icm = NULL;
330	LogFlowFunc(("iEntries:%d\n", iEntries));
331	if (iEntries > icmp_cache_count(pData))
332	{
333	LogFlowFuncLeave();
334	return;
335	}
336	while(!LIST_EMPTY(&pData->icmp_msg_head))
337	{
338	icm = LIST_FIRST(&pData->icmp_msg_head);
339	if ( iEntries > 0
340	&& iIcmpCount < iEntries)
341	{
342	iIcmpCount++;
343	continue;
344	}
345
346	LIST_REMOVE(icm, im_list);
347	if (icm->im_m)
348	m_freem(pData, icm->im_m);
349	RTMemFree(icm);
350	}
351	LogFlowFuncLeave();
352	}
353
354	static int
355	icmp_attach(PNATState pData, struct mbuf *m)
356	{
357	struct icmp_msg *icm;
358	struct ip *ip;
359	ip = mtod(m, struct ip *);
360	Assert(ip->ip_p == IPPROTO_ICMP);
361	icm = RTMemAlloc(sizeof(struct icmp_msg));
362	icm->im_m = m;
363	icm->im_so = m->m_so;
364	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
365	if (icmp_cache_count(pData) > 100)
366	icmp_cache_clean(pData, 50);
367	return 0;
368	}
369
370	/*
371	* Process a received ICMP message.
372	*/
373	void
374	icmp_input(PNATState pData, struct mbuf *m, int hlen)
375	{
376	register struct icmp *icp;
377	void *icp_buf = NULL;
378	register struct ip ip = mtod(m, struct ip );
379	int icmplen = ip->ip_len;
380	int status;
381	uint32_t dst;
382	#if !defined(RT_OS_WINDOWS)
383	int ttl;
384	#endif
385
386	/* int code; */
387
388	LogFlowFunc(("ENTER: m = %lx, m_len = %d\n", (long)m, m ? m->m_len : 0));
389
390	icmpstat.icps_received++;
391
392	/*
393	* Locate icmp structure in mbuf, and check
394	* that its not corrupted and of at least minimum length.
395	*/
396	if (icmplen < ICMP_MINLEN)
397	{
398	/* min 8 bytes payload */
399	icmpstat.icps_tooshort++;
400	goto end_error_free_m;
401	}
402
403	m->m_len -= hlen;
404	m->m_data += hlen;
405
406	if (cksum(m, icmplen))
407	{
408	icmpstat.icps_checksum++;
409	goto end_error_free_m;
410	}
411
412	if (m->m_next)
413	{
414	icp_buf = RTMemAlloc(icmplen);
415	if (!icp_buf)
416	{
417	Log(("NAT: not enought memory to allocate the buffer\n"));
418	goto end_error_free_m;
419	}
420	m_copydata(m, 0, icmplen, icp_buf);
421	icp = (struct icmp *)icp_buf;
422	}
423	else
424	icp = mtod(m, struct icmp *);
425
426	m->m_len += hlen;
427	m->m_data -= hlen;
428
429	/* icmpstat.icps_inhist[icp->icmp_type]++; */
430	/* code = icp->icmp_code; */
431
432	LogFlow(("icmp_type = %d\n", icp->icmp_type));
433	switch (icp->icmp_type)
434	{
435	case ICMP_ECHO:
436	ip->ip_len += hlen; /* since ip_input subtracts this */
437	dst = ip->ip_dst.s_addr;
438	if (dst == alias_addr.s_addr)
439	{
440	icp->icmp_type = ICMP_ECHOREPLY;
441	ip->ip_dst.s_addr = ip->ip_src.s_addr;
442	ip->ip_src.s_addr = dst;
443	icmp_reflect(pData, m);
444	goto done;
445	}
446	else
447	{
448	struct sockaddr_in addr;
449	#ifdef RT_OS_WINDOWS
450	IP_OPTION_INFORMATION ipopt;
451	int error;
452	#endif
453	addr.sin_family = AF_INET;
454	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
455	{
456	/* It's an alias */
457	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
458	{
459	case CTL_DNS:
460	case CTL_ALIAS:
461	default:
462	addr.sin_addr = loopback_addr;
463	break;
464	}
465	}
466	else
467	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
468	#ifndef RT_OS_WINDOWS
469	if (pData->icmp_socket.s != -1)
470	{
471	ssize_t rc;
472	static bool fIcmpSocketErrorReported;
473	ttl = ip->ip_ttl;
474	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
475	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
476	(void *)&ttl, sizeof(ttl));
477	if (status < 0)
478	Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
479	strerror(errno)));
480	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
481	(struct sockaddr *)&addr, sizeof(addr));
482	if (rc >= 0)
483	{
484	m->m_so = &pData->icmp_socket;
485	icmp_attach(pData, m);
486	/* don't let m_freem at the end free atached buffer */
487	goto done;
488	}
489
490
491	if (!fIcmpSocketErrorReported)
492	{
493	LogRel(("icmp_input udp sendto tx errno = %d (%s)\n",
494	errno, strerror(errno)));
495	fIcmpSocketErrorReported = true;
496	}
497	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
498	}
499	#else /* RT_OS_WINDOWS */
500	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
501	pData->icmp_socket.so_icmp_id = icp->icmp_id;
502	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
503	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
504	ipopt.Ttl = ip->ip_ttl;
505	status = IcmpSendEcho2(pData->icmp_socket.sh /=handle/,
506	pData->phEvents[VBOX_ICMP_EVENT_INDEX] /=Event/,
507	NULL /=ApcRoutine/,
508	NULL /=ApcContext/,
509	addr.sin_addr.s_addr /=DestinationAddress/,
510	icp->icmp_data /=RequestData/,
511	icmplen - ICMP_MINLEN /=RequestSize/,
512	&ipopt /=RequestOptions/,
513	pData->pvIcmpBuffer /=ReplyBuffer/,
514	pData->szIcmpBuffer /=ReplySize/,
515	1 /=Timeout in ms/);
516	error = GetLastError();
517	if ( status != 0
518	\|\| error == ERROR_IO_PENDING)
519	{
520	/* no error! */
521	m->m_so = &pData->icmp_socket;
522	icmp_attach(pData, m);
523	/* don't let m_freem at the end free atached buffer */
524	goto done;
525	}
526	Log(("NAT: Error (%d) occurred while sending ICMP (", error));
527	switch (error)
528	{
529	case ERROR_INVALID_PARAMETER:
530	Log(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
531	break;
532	case ERROR_NOT_SUPPORTED:
533	Log(("operation is unsupported)\n"));
534	break;
535	case ERROR_NOT_ENOUGH_MEMORY:
536	Log(("OOM!!!)\n"));
537	break;
538	case IP_BUF_TOO_SMALL:
539	Log(("Buffer too small)\n"));
540	break;
541	default:
542	Log(("Other error!!!)\n"));
543	break;
544	}
545	#endif /* RT_OS_WINDOWS */
546	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
547	break;
548	case ICMP_UNREACH:
549	case ICMP_TIMXCEED:
550	/* @todo(vvl): both up cases comes from guest,
551	* indeed right solution would be find the socket
552	* corresponding to ICMP data and close it.
553	*/
554	case ICMP_PARAMPROB:
555	case ICMP_SOURCEQUENCH:
556	case ICMP_TSTAMP:
557	case ICMP_MASKREQ:
558	case ICMP_REDIRECT:
559	icmpstat.icps_notsupp++;
560	break;
561
562	default:
563	icmpstat.icps_badtype++;
564	} /* switch */
565
566	end_error_free_m:
567	m_freem(pData, m);
568
569	done:
570	if (icp_buf)
571	RTMemFree(icp_buf);
572	}
573
574
575	/**
576	* Send an ICMP message in response to a situation
577	*
578	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
579	* MUST NOT change this header information.
580	* MUST NOT reply to a multicast/broadcast IP address.
581	* MUST NOT reply to a multicast/broadcast MAC address.
582	* MUST reply to only the first fragment.
583	*
584	* Send ICMP_UNREACH back to the source regarding msrc.
585	* It is reported as the bad ip packet. The header should
586	* be fully correct and in host byte order.
587	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
588	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
589	*
590	* @note This function will free msrc!
591	*/
592
593	#define ICMP_MAXDATALEN (IP_MSS-28)
594	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
595	{
596	unsigned hlen, shlen, s_ip_len;
597	register struct ip *ip;
598	register struct icmp *icp;
599	register struct mbuf *m;
600	int new_m_size = 0;
601	int size = 0;
602
603	LogFlow(("icmp_error: msrc = %lx, msrc_len = %d\n", (long)msrc, msrc ? msrc->m_len : 0));
604	if (msrc != NULL)
605	M_ASSERTPKTHDR(msrc);
606
607	if ( type != ICMP_UNREACH
608	&& type != ICMP_TIMXCEED
609	&& type != ICMP_SOURCEQUENCH)
610	goto end_error;
611
612	/* check msrc */
613	if (!msrc)
614	goto end_error;
615
616	ip = mtod(msrc, struct ip *);
617	#if DEBUG
618	{
619	char bufa[20], bufb[20];
620	strcpy(bufa, inet_ntoa(ip->ip_src));
621	strcpy(bufb, inet_ntoa(ip->ip_dst));
622	Log2((" %.16s to %.16s\n", bufa, bufb));
623	}
624	#endif
625	if ( ip->ip_off & IP_OFFMASK
626	&& type != ICMP_SOURCEQUENCH)
627	goto end_error; /* Only reply to fragment 0 */
628
629	shlen = ip->ip_hl << 2;
630	s_ip_len = ip->ip_len;
631	if (ip->ip_p == IPPROTO_ICMP)
632	{
633	icp = (struct icmp )((char )ip + shlen);
634	/*
635	* Assume any unknown ICMP type is an error. This isn't
636	* specified by the RFC, but think about it..
637	*/
638	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
639	goto end_error;
640	}
641
642	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
643	if (new_m_size < MSIZE)
644	size = MCLBYTES;
645	else if (new_m_size < MCLBYTES)
646	size = MCLBYTES;
647	else if(new_m_size < MJUM9BYTES)
648	size = MJUM9BYTES;
649	else if (new_m_size < MJUM16BYTES)
650	size = MJUM16BYTES;
651	else
652	AssertMsgFailed(("Unsupported size"));
653	m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
654	if (!m)
655	goto end_error;
656
657	m->m_data += if_maxlinkhdr;
658	m->m_pkthdr.header = mtod(m, void *);
659
660	memcpy(m->m_data, msrc->m_data, msrc->m_len);
661	m->m_len = msrc->m_len; /* copy msrc to m */
662
663	/* make the header of the reply packet */
664	ip = mtod(m, struct ip *);
665	hlen = sizeof(struct ip); /* no options in reply */
666
667	/* fill in icmp */
668	m->m_data += hlen;
669	m->m_len -= hlen;
670
671	icp = mtod(m, struct icmp *);
672
673	if (minsize)
674	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
675	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
676	s_ip_len = ICMP_MAXDATALEN;
677
678	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
679
680	/* min. size = 8+sizeof(struct ip)+8 */
681
682	icp->icmp_type = type;
683	icp->icmp_code = code;
684	icp->icmp_id = 0;
685	icp->icmp_seq = 0;
686
687	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
688
689	HTONS(icp->icmp_ip.ip_len);
690	HTONS(icp->icmp_ip.ip_id);
691	HTONS(icp->icmp_ip.ip_off);
692
693	#if DEBUG
694	if (message)
695	{
696	/* DEBUG : append message to ICMP packet */
697	int message_len;
698	char *cpnt;
699	message_len = strlen(message);
700	if (message_len > ICMP_MAXDATALEN)
701	message_len = ICMP_MAXDATALEN;
702	cpnt = (char *)m->m_data+m->m_len;
703	m_append(pData, m, message_len, message);
704	}
705	#endif
706
707	icp->icmp_cksum = 0;
708	icp->icmp_cksum = cksum(m, m->m_len);
709
710	/* fill in ip */
711	ip->ip_hl = hlen >> 2;
712	ip->ip_len = m->m_len;
713
714	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
715
716	ip->ip_ttl = MAXTTL;
717	ip->ip_p = IPPROTO_ICMP;
718	ip->ip_dst = ip->ip_src; /* ip adresses */
719	ip->ip_src = alias_addr;
720
721	/* returns pointer back. */
722	m->m_data -= hlen;
723	m->m_len += hlen;
724	(void) ip_output0(pData, (struct socket *)NULL, m, 1);
725
726	icmpstat.icps_reflect++;
727
728	/* clear source datagramm in positive branch */
729	m_freem(pData, msrc);
730	LogFlowFuncLeave();
731	return;
732
733	end_error_free_m:
734	m_freem(pData, m);
735
736	end_error:
737
738	/*
739	* clear source datagramm in case if some of requirement haven't been met.
740	*/
741	if (!msrc)
742	m_freem(pData, msrc);
743
744	{
745	static bool fIcmpErrorReported;
746	if (!fIcmpErrorReported)
747	{
748	LogRel(("NAT: error occurred while sending ICMP error message\n"));
749	fIcmpErrorReported = true;
750	}
751	}
752	LogFlowFuncLeave();
753	}
754	#undef ICMP_MAXDATALEN
755
756	/*
757	* Reflect the ip packet back to the source
758	* Note: m isn't duplicated by this method and more delivered to ip_output then.
759	*/
760	void
761	icmp_reflect(PNATState pData, struct mbuf *m)
762	{
763	register struct ip ip = mtod(m, struct ip );
764	int hlen = ip->ip_hl << 2;
765	int optlen = hlen - sizeof(struct ip);
766	register struct icmp *icp;
767	LogFlowFunc(("ENTER: m:%p\n", m));
768
769	/*
770	* Send an icmp packet back to the ip level,
771	* after supplying a checksum.
772	*/
773	m->m_data += hlen;
774	m->m_len -= hlen;
775	icp = mtod(m, struct icmp *);
776
777	icp->icmp_cksum = 0;
778	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
779
780	m->m_data -= hlen;
781	m->m_len += hlen;
782
783	(void) ip_output(pData, (struct socket *)NULL, m);
784
785	icmpstat.icps_reflect++;
786	LogFlowFuncLeave();
787	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 38927

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