ip_icmp.c@ 53309

Last change on this file since 53309 was 53309, checked in by vboxsync, 10 years ago
NAT: don't create contiguous copy of all large ICMP datagrams, only do one when necessary.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 24.0 KB

Line
1	/* $Id: ip_icmp.c 53309 2014-11-12 03:47:13Z vboxsync $ */
2	/** @file
3	* NAT - IP/ICMP handling.
4	*/
5
6	/*
7	* Copyright (C) 2006-2012 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	# include <iprt/ldr.h>
62	#endif
63
64	/* The message sent when emulating PING */
65	/* Be nice and tell them it's just a psuedo-ping packet */
66	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
67
68	/* list of actions for icmp_error() on RX of an icmp message */
69	static const int icmp_flush[19] =
70	{
71	/* ECHO REPLY (0) */ 0,
72	1,
73	1,
74	/* DEST UNREACH (3) */ 1,
75	/* SOURCE QUENCH (4)*/ 1,
76	/* REDIRECT (5) */ 1,
77	1,
78	1,
79	/* ECHO (8) */ 0,
80	/* ROUTERADVERT (9) */ 1,
81	/* ROUTERSOLICIT (10) */ 1,
82	/* TIME EXCEEDED (11) */ 1,
83	/* PARAMETER PROBLEM (12) */ 1,
84	/* TIMESTAMP (13) */ 0,
85	/* TIMESTAMP REPLY (14) */ 0,
86	/* INFO (15) */ 0,
87	/* INFO REPLY (16) */ 0,
88	/* ADDR MASK (17) */ 0,
89	/* ADDR MASK REPLY (18) */ 0
90	};
91
92	static void icmp_cache_clean(PNATState pData, int iEntries);
93
94	int
95	icmp_init(PNATState pData, int iIcmpCacheLimit)
96	{
97	pData->icmp_socket.so_type = IPPROTO_ICMP;
98	pData->icmp_socket.so_state = SS_ISFCONNECTED;
99	if (iIcmpCacheLimit < 0)
100	{
101	LogRel(("NAT: iIcmpCacheLimit is invalid %d, will be alter to default value 100\n", iIcmpCacheLimit));
102	iIcmpCacheLimit = 100;
103	}
104	pData->iIcmpCacheLimit = iIcmpCacheLimit;
105	#ifndef RT_OS_WINDOWS
106	# ifndef RT_OS_DARWIN
107	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
108	# else /* !RT_OS_DARWIN */
109	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
110	# endif /* RT_OS_DARWIN */
111	if (pData->icmp_socket.s == -1)
112	{
113	int rc = RTErrConvertFromErrno(errno);
114	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
115	return 1;
116	}
117	fd_nonblock(pData->icmp_socket.s);
118	NSOCK_INC();
119
120	#else /* RT_OS_WINDOWS */
121	if (icmpwin_init(pData) != 0)
122	return 1;
123	#endif /* RT_OS_WINDOWS */
124
125	LIST_INIT(&pData->icmp_msg_head);
126	return 0;
127	}
128
129	/**
130	* Cleans ICMP cache.
131	*/
132	void
133	icmp_finit(PNATState pData)
134	{
135	icmp_cache_clean(pData, -1);
136	#ifdef RT_OS_WINDOWS
137	icmpwin_finit(pData);
138	#else
139	closesocket(pData->icmp_socket.s);
140	#endif
141	}
142
143	/*
144	* ip here is ip header + 64bytes readed from ICMP packet
145	*/
146	struct icmp_msg *
147	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
148	{
149	struct mbuf *m0;
150	struct ip *ip0;
151	struct icmp icp, icp0;
152	struct icmp_msg *icm = NULL;
153	int found = 0;
154	struct udphdr *udp;
155	struct tcphdr *tcp;
156	struct socket *head_socket = NULL;
157	struct socket *last_socket = NULL;
158	struct socket *so = NULL;
159	struct in_addr faddr;
160	u_short lport, fport;
161
162	faddr.s_addr = ~0;
163
164	lport = ~0;
165	fport = ~0;
166
167
168	LogFlowFunc(("ENTER: ip->ip_p:%d\n", ip->ip_p));
169	switch (ip->ip_p)
170	{
171	case IPPROTO_ICMP:
172	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
173	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
174	{
175	m0 = icm->im_m;
176	ip0 = mtod(m0, struct ip *);
177	if (ip0->ip_p != IPPROTO_ICMP)
178	{
179	/* try next item */
180	continue;
181	}
182	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
183	/*
184	* IP could pointer to ICMP_REPLY datagram (1)
185	* or pointer IP header in ICMP payload in case of
186	* ICMP_TIMXCEED or ICMP_UNREACH (2)
187	*
188	* if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
189	* IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
190	*
191	* if (2) then check that payload ICMP has got type ICMP_ECHO and
192	* IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
193	* one was sent.
194	*/
195	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
196	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
197	&& icp->icmp_id == icp0->icmp_id
198	&& icp->icmp_seq == icp0->icmp_seq)
199	{
200	found = 1;
201	Log(("Have found %R[natsock]\n", icm->im_so));
202	break;
203	}
204	Log(("Have found nothing\n"));
205	}
206	break;
207
208	/*
209	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
210	* from which the IP package has been sent.
211	*/
212	case IPPROTO_UDP:
213	head_socket = &udb;
214	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
215	faddr.s_addr = ip->ip_dst.s_addr;
216	fport = udp->uh_dport;
217	lport = udp->uh_sport;
218	last_socket = udp_last_so;
219	/* fall through */
220
221	case IPPROTO_TCP:
222	if (head_socket == NULL)
223	{
224	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
225	head_socket = &tcb; /* head_socket could be initialized with udb*/
226	faddr.s_addr = ip->ip_dst.s_addr;
227	fport = tcp->th_dport;
228	lport = tcp->th_sport;
229	last_socket = tcp_last_so;
230	}
231	/* check last socket first */
232	if ( last_socket->so_faddr.s_addr == faddr.s_addr
233	&& last_socket->so_fport == fport
234	&& last_socket->so_hlport == lport)
235	{
236	found = 1;
237	so = last_socket;
238	goto sofound;
239	}
240	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
241	{
242	/* Should be reaplaced by hash here */
243	Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
244	if ( so->so_faddr.s_addr == faddr.s_addr
245	&& so->so_fport == fport
246	&& so->so_hlport == lport)
247	{
248	found = 1;
249	break;
250	}
251	}
252	break;
253
254	default:
255	Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
256	}
257	sofound:
258	if (found == 1 && icm == NULL)
259	{
260	if (so->so_state == SS_NOFDREF)
261	{
262	/* socket is shutdowning we've already sent ICMP on it.*/
263	Log(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
264	return NULL;
265	}
266	icm = RTMemAlloc(sizeof(struct icmp_msg));
267	icm->im_m = so->so_m;
268	icm->im_so = so;
269	found = 1;
270	Log(("hit:%R[natsock]\n", so));
271	/*XXX: this storage not very long,
272	* better add flag if it should removed from lis
273	*/
274	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
275	pData->cIcmpCacheSize++;
276	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
277	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
278	LogFlowFunc(("LEAVE: icm:%p\n", icm));
279	return (icm);
280	}
281	if (found == 1)
282	{
283	LogFlowFunc(("LEAVE: icm:%p\n", icm));
284	return icm;
285	}
286
287	LogFlowFunc(("LEAVE: NULL\n"));
288	return NULL;
289	}
290
291	/**
292	* iEntries how many entries to leave, if iEntries < 0, clean all
293	*/
294	static void icmp_cache_clean(PNATState pData, int iEntries)
295	{
296	int iIcmpCount = 0;
297	struct icmp_msg *icm = NULL;
298	LogFlowFunc(("iEntries:%d\n", iEntries));
299	if (iEntries > pData->cIcmpCacheSize)
300	{
301	LogFlowFuncLeave();
302	return;
303	}
304	while(!LIST_EMPTY(&pData->icmp_msg_head))
305	{
306	icm = LIST_FIRST(&pData->icmp_msg_head);
307	if ( iEntries > 0
308	&& iIcmpCount < iEntries)
309	{
310	iIcmpCount++;
311	continue;
312	}
313
314	LIST_REMOVE(icm, im_list);
315	if (icm->im_m)
316	{
317	pData->cIcmpCacheSize--;
318	m_freem(pData, icm->im_m);
319	}
320	RTMemFree(icm);
321	}
322	LogFlowFuncLeave();
323	}
324
325	static int
326	icmp_attach(PNATState pData, struct mbuf *m)
327	{
328	struct icmp_msg *icm;
329	struct ip *ip;
330	ip = mtod(m, struct ip *);
331	Assert(ip->ip_p == IPPROTO_ICMP);
332	icm = RTMemAlloc(sizeof(struct icmp_msg));
333	icm->im_m = m;
334	icm->im_so = m->m_so;
335	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
336	pData->cIcmpCacheSize++;
337	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
338	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
339	return 0;
340	}
341
342	/*
343	* Process a received ICMP message.
344	*/
345	void
346	icmp_input(PNATState pData, struct mbuf *m, int hlen)
347	{
348	register struct ip ip = mtod(m, struct ip );
349	int icmplen = ip->ip_len;
350	uint8_t icmp_type;
351	void *icp_buf = NULL;
352	int status;
353	uint32_t dst;
354	#if !defined(RT_OS_WINDOWS)
355	int ttl;
356	#endif
357
358	/* int code; */
359
360	LogFlowFunc(("ENTER: m = %lx, m_len = %d\n", (long)m, m ? m->m_len : 0));
361
362	icmpstat.icps_received++;
363
364	/*
365	* Locate icmp structure in mbuf, and check
366	* that its not corrupted and of at least minimum length.
367	*/
368	if (icmplen < ICMP_MINLEN)
369	{
370	/* min 8 bytes payload */
371	icmpstat.icps_tooshort++;
372	goto end_error_free_m;
373	}
374
375	m->m_len -= hlen;
376	m->m_data += hlen;
377
378	if (cksum(m, icmplen))
379	{
380	icmpstat.icps_checksum++;
381	goto end_error_free_m;
382	}
383
384	/* are we guaranteed to have ICMP header in first mbuf? be safe. */
385	m_copydata(m, 0, sizeof(icmp_type), (caddr_t)&icmp_type);
386
387	m->m_len += hlen;
388	m->m_data -= hlen;
389
390	/* icmpstat.icps_inhist[icp->icmp_type]++; */
391	/* code = icp->icmp_code; */
392
393	LogFlow(("icmp_type = %d\n", icmp_type));
394	switch (icmp_type)
395	{
396	case ICMP_ECHO:
397	ip->ip_len += hlen; /* since ip_input subtracts this */
398	dst = ip->ip_dst.s_addr;
399	if ( CTL_CHECK(dst, CTL_ALIAS)
400	\|\| CTL_CHECK(dst, CTL_DNS)
401	\|\| CTL_CHECK(dst, CTL_TFTP))
402	{
403	uint8_t echo_reply = ICMP_ECHOREPLY;
404	m_copyback(pData, m, hlen + RT_OFFSETOF(struct icmp, icmp_type),
405	sizeof(echo_reply), (caddr_t)&echo_reply);
406	ip->ip_dst.s_addr = ip->ip_src.s_addr;
407	ip->ip_src.s_addr = dst;
408	icmp_reflect(pData, m);
409	goto done;
410	}
411	else
412	{
413	struct icmp *icp;
414	struct sockaddr_in addr;
415	#ifdef RT_OS_WINDOWS
416	IP_OPTION_INFORMATION ipopt;
417	int error;
418	#endif
419	addr.sin_family = AF_INET;
420	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
421	{
422	/* It's an alias */
423	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
424	{
425	case CTL_DNS:
426	case CTL_ALIAS:
427	default:
428	addr.sin_addr = loopback_addr;
429	break;
430	}
431	}
432	else
433	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
434
435	if (m->m_next)
436	{
437	icp_buf = RTMemAlloc(icmplen);
438	if (!icp_buf)
439	{
440	Log(("NAT: not enought memory to allocate the buffer\n"));
441	goto end_error_free_m;
442	}
443	m_copydata(m, hlen, icmplen, icp_buf);
444	icp = (struct icmp *)icp_buf;
445	}
446	else
447	icp = (struct icmp )(mtod(m, char ) + hlen);
448
449	#ifndef RT_OS_WINDOWS
450	if (pData->icmp_socket.s != -1)
451	{
452	ssize_t rc;
453	static bool fIcmpSocketErrorReported;
454	ttl = ip->ip_ttl;
455	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
456	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
457	(void *)&ttl, sizeof(ttl));
458	if (status < 0)
459	Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
460	strerror(errno)));
461	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
462	(struct sockaddr *)&addr, sizeof(addr));
463	if (rc >= 0)
464	{
465	m->m_so = &pData->icmp_socket;
466	icmp_attach(pData, m);
467	/* don't let m_freem at the end free atached buffer */
468	goto done;
469	}
470
471
472	if (!fIcmpSocketErrorReported)
473	{
474	LogRel(("icmp_input udp sendto tx errno = %d (%s)\n",
475	errno, strerror(errno)));
476	fIcmpSocketErrorReported = true;
477	}
478	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
479	}
480	#else /* RT_OS_WINDOWS */
481	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
482	pData->icmp_socket.so_icmp_id = icp->icmp_id;
483	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
484	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
485	ipopt.Ttl = ip->ip_ttl;
486	status = IcmpSendEcho2(pData->icmp_socket.sh /=handle/,
487	pData->phEvents[VBOX_ICMP_EVENT_INDEX] /=Event/,
488	NULL /=ApcRoutine/,
489	NULL /=ApcContext/,
490	addr.sin_addr.s_addr /=DestinationAddress/,
491	icp->icmp_data /=RequestData/,
492	icmplen - ICMP_MINLEN /=RequestSize/,
493	&ipopt /=RequestOptions/,
494	pData->pvIcmpBuffer /=ReplyBuffer/,
495	pData->cbIcmpBuffer /=ReplySize/,
496	1 /=Timeout in ms/);
497	error = GetLastError();
498	if ( status != 0
499	\|\| error == ERROR_IO_PENDING)
500	{
501	/* no error! */
502	m->m_so = &pData->icmp_socket;
503	icmp_attach(pData, m);
504	/* don't let m_freem at the end free atached buffer */
505	goto done;
506	}
507	Log(("NAT: Error (%d) occurred while sending ICMP (", error));
508	switch (error)
509	{
510	case ERROR_INVALID_PARAMETER:
511	Log(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
512	break;
513	case ERROR_NOT_SUPPORTED:
514	Log(("operation is unsupported)\n"));
515	break;
516	case ERROR_NOT_ENOUGH_MEMORY:
517	Log(("OOM!!!)\n"));
518	break;
519	case IP_BUF_TOO_SMALL:
520	Log(("Buffer too small)\n"));
521	break;
522	default:
523	Log(("Other error!!!)\n"));
524	break;
525	}
526	#endif /* RT_OS_WINDOWS */
527	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
528	break;
529	case ICMP_UNREACH:
530	case ICMP_TIMXCEED:
531	/* @todo(vvl): both up cases comes from guest,
532	* indeed right solution would be find the socket
533	* corresponding to ICMP data and close it.
534	*/
535	case ICMP_PARAMPROB:
536	case ICMP_SOURCEQUENCH:
537	case ICMP_TSTAMP:
538	case ICMP_MASKREQ:
539	case ICMP_REDIRECT:
540	icmpstat.icps_notsupp++;
541	break;
542
543	default:
544	icmpstat.icps_badtype++;
545	} /* switch */
546
547	end_error_free_m:
548	m_freem(pData, m);
549
550	done:
551	if (icp_buf)
552	RTMemFree(icp_buf);
553	}
554
555
556	/**
557	* Send an ICMP message in response to a situation
558	*
559	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
560	* MUST NOT change this header information.
561	* MUST NOT reply to a multicast/broadcast IP address.
562	* MUST NOT reply to a multicast/broadcast MAC address.
563	* MUST reply to only the first fragment.
564	*
565	* Send ICMP_UNREACH back to the source regarding msrc.
566	* It is reported as the bad ip packet. The header should
567	* be fully correct and in host byte order.
568	* ICMP fragmentation is illegal.
569	*
570	* @note: implementation note: MSIZE is 256 bytes (minimal buffer).
571	* We always truncate original payload to 8 bytes required by the RFC,
572	* so the largest possible datagram is 14 (ethernet) + 20 (ip) +
573	* 8 (icmp) + 60 (max original ip with options) + 8 (original payload)
574	* = 110 bytes which fits into sinlge mbuf.
575	*
576	* @note This function will free msrc!
577	*/
578
579	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
580	{
581	unsigned ohlen, olen;
582	struct mbuf *m;
583	struct ip oip, ip;
584	struct icmp *icp;
585	void *payload;
586
587	LogFlow(("icmp_error: msrc = %p, msrc_len = %d\n",
588	(void *)msrc, msrc ? msrc->m_len : 0));
589
590	if (RT_UNLIKELY(msrc == NULL))
591	goto end_error;
592
593	M_ASSERTPKTHDR(msrc);
594
595	if ( type != ICMP_UNREACH
596	&& type != ICMP_TIMXCEED
597	&& type != ICMP_SOURCEQUENCH)
598	goto end_error;
599
600	oip = mtod(msrc, struct ip *);
601	LogFunc(("msrc: %RTnaipv4 -> %RTnaipv4\n", oip->ip_src, oip->ip_dst));
602
603	if (oip->ip_src.s_addr == INADDR_ANY)
604	goto end_error;
605
606	if (oip->ip_off & IP_OFFMASK)
607	goto end_error; /* Only reply to fragment 0 */
608
609	ohlen = oip->ip_hl * 4;
610	AssertStmt(ohlen >= sizeof(struct ip), goto end_error);
611
612	olen = oip->ip_len;
613	AssertStmt(olen >= ohlen, goto end_error);
614
615	if (oip->ip_p == IPPROTO_ICMP)
616	{
617	struct icmp oicp = (struct icmp )((char *)oip + ohlen);
618	/*
619	* Assume any unknown ICMP type is an error. This isn't
620	* specified by the RFC, but think about it..
621	*/
622	if (oicp->icmp_type > ICMP_MAXTYPE \|\| icmp_flush[oicp->icmp_type])
623	goto end_error;
624	}
625
626	/* undo byte order conversions done in ip_input() */
627	HTONS(oip->ip_len);
628	HTONS(oip->ip_id);
629	HTONS(oip->ip_off);
630
631	m = m_gethdr(pData, M_NOWAIT, MT_HEADER);
632	if (RT_UNLIKELY(m == NULL))
633	goto end_error;
634
635	m->m_flags \|= M_SKIP_FIREWALL;
636	m->m_data += if_maxlinkhdr;
637
638	ip = mtod(m, struct ip *);
639	m->m_pkthdr.header = (void *)ip;
640
641	/* fill in ip (ip_output0() does the boilerplate for us) */
642	ip->ip_tos = ((oip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
643	/* ip->ip_len will be set later */
644	ip->ip_off = 0;
645	ip->ip_ttl = MAXTTL;
646	ip->ip_p = IPPROTO_ICMP;
647	ip->ip_src = alias_addr;
648	ip->ip_dst = oip->ip_src;
649
650	/* fill in icmp */
651	icp = (struct icmp )((char )ip + sizeof(*ip));
652	icp->icmp_type = type;
653	icp->icmp_code = code;
654	icp->icmp_id = 0;
655	icp->icmp_seq = 0;
656
657	/* fill in icmp payload: original ip header plus 8 bytes of its payload */
658	if (olen > ohlen + 8)
659	olen = ohlen + 8;
660	payload = (void )((char )icp + ICMP_MINLEN);
661	memcpy(payload, oip, olen);
662
663	/*
664	* Original code appended this message after the payload. This
665	* might have been a good idea for real slirp, as it provided a
666	* communication channel with the remote host. But 90s are over.
667	*/
668	NOREF(message);
669
670	/* hide ip header for icmp checksum calculation */
671	m->m_data += sizeof(struct ip);
672	m->m_len = ICMP_MINLEN + /* truncated */ olen;
673
674	icp->icmp_cksum = 0;
675	icp->icmp_cksum = cksum(m, m->m_len);
676
677	/* reveal ip header */
678	m->m_data -= sizeof(struct ip);
679	m->m_len += sizeof(struct ip);
680	ip->ip_len = m->m_len;
681
682	(void) ip_output0(pData, (struct socket *)NULL, m, 1);
683
684	icmpstat.icps_reflect++;
685
686	/* clear source datagramm in positive branch */
687	m_freem(pData, msrc);
688	LogFlowFuncLeave();
689	return;
690
691	end_error:
692
693	/*
694	* clear source datagramm in case if some of requirement haven't been met.
695	*/
696	if (msrc)
697	m_freem(pData, msrc);
698
699	{
700	static bool fIcmpErrorReported;
701	if (!fIcmpErrorReported)
702	{
703	LogRel(("NAT: error occurred while sending ICMP error message\n"));
704	fIcmpErrorReported = true;
705	}
706	}
707	LogFlowFuncLeave();
708	}
709
710	/*
711	* Reflect the ip packet back to the source
712	* Note: m isn't duplicated by this method and more delivered to ip_output then.
713	*/
714	void
715	icmp_reflect(PNATState pData, struct mbuf *m)
716	{
717	register struct ip ip = mtod(m, struct ip );
718	int hlen = ip->ip_hl << 2;
719	register struct icmp *icp;
720	LogFlowFunc(("ENTER: m:%p\n", m));
721
722	/*
723	* Send an icmp packet back to the ip level,
724	* after supplying a checksum.
725	*/
726	m->m_data += hlen;
727	m->m_len -= hlen;
728	icp = mtod(m, struct icmp *);
729
730	icp->icmp_cksum = 0;
731	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
732
733	m->m_data -= hlen;
734	m->m_len += hlen;
735
736	(void) ip_output(pData, (struct socket *)NULL, m);
737
738	icmpstat.icps_reflect++;
739	LogFlowFuncLeave();
740	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 53309

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