ip_icmp.c@ 63012

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1	/* $Id: ip_icmp.c 63012 2016-08-04 21:25:17Z vboxsync $ */
2	/** @file
3	* NAT - IP/ICMP handling.
4	*/
5
6	/*
7	* Copyright (C) 2006-2016 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.215389.xyz. 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
59	#ifdef VBOX_RAWSOCK_DEBUG_HELPER
60	int getrawsock(int type);
61	#endif
62
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
93	int
94	icmp_init(PNATState pData, int iIcmpCacheLimit)
95	{
96	pData->icmp_socket.so_type = IPPROTO_ICMP;
97	pData->icmp_socket.so_state = SS_ISFCONNECTED;
98
99	#ifndef RT_OS_WINDOWS
100	TAILQ_INIT(&pData->icmp_msg_head);
101
102	if (iIcmpCacheLimit < 0)
103	{
104	LogRel(("NAT: iIcmpCacheLimit is invalid %d, will be alter to default value 100\n", iIcmpCacheLimit));
105	iIcmpCacheLimit = 100;
106	}
107	pData->iIcmpCacheLimit = iIcmpCacheLimit;
108	# ifndef RT_OS_DARWIN
109	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
110	# else /* !RT_OS_DARWIN */
111	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
112	# endif /* RT_OS_DARWIN */
113	if (pData->icmp_socket.s == -1)
114	{
115	int rc = RTErrConvertFromErrno(errno);
116	# if defined(RT_OS_DARWIN) \|\| !defined(VBOX_RAWSOCK_DEBUG_HELPER)
117	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
118	return 1;
119	# else
120	/* try to get it from privileged helper */
121	LogRel(("NAT: ICMP/ping raw socket error %Rrc, asking helper...\n", rc));
122	pData->icmp_socket.s = getrawsock(AF_INET);
123	if (pData->icmp_socket.s == -1)
124	{
125	LogRel(("NAT: ICMP/ping not available\n"));
126	return 1;
127	}
128	# endif /* !RT_OS_DARWIN && VBOX_RAWSOCK_DEBUG_HELPER */
129	}
130	fd_nonblock(pData->icmp_socket.s);
131	NSOCK_INC();
132
133	#else /* RT_OS_WINDOWS */
134	RT_NOREF(iIcmpCacheLimit);
135
136	if (icmpwin_init(pData) != 0)
137	return 1;
138	#endif /* RT_OS_WINDOWS */
139
140	return 0;
141	}
142
143	/**
144	* Cleans ICMP cache.
145	*/
146	void
147	icmp_finit(PNATState pData)
148	{
149	#ifdef RT_OS_WINDOWS
150	icmpwin_finit(pData);
151	#else
152	while (!TAILQ_EMPTY(&pData->icmp_msg_head))
153	{
154	struct icmp_msg *icm = TAILQ_FIRST(&pData->icmp_msg_head);
155	icmp_msg_delete(pData, icm);
156	}
157	closesocket(pData->icmp_socket.s);
158	#endif
159	}
160
161
162	#if !defined(RT_OS_WINDOWS)
163	static struct icmp_msg *
164	icmp_msg_alloc(PNATState pData)
165	{
166	struct icmp_msg *icm;
167
168	#ifdef DEBUG
169	{
170	int iTally = 0;
171	TAILQ_FOREACH(icm, &pData->icmp_msg_head, im_queue)
172	++iTally;
173	Assert(pData->cIcmpCacheSize == iTally);
174	}
175	#endif
176
177	if (pData->cIcmpCacheSize >= pData->iIcmpCacheLimit)
178	{
179	int cTargetCacheSize = pData->iIcmpCacheLimit/2;
180
181	while (pData->cIcmpCacheSize > cTargetCacheSize)
182	{
183	icm = TAILQ_FIRST(&pData->icmp_msg_head);
184	icmp_msg_delete(pData, icm);
185	}
186	}
187
188	icm = RTMemAlloc(sizeof(struct icmp_msg));
189	if (RT_UNLIKELY(icm == NULL))
190	return NULL;
191
192	TAILQ_INSERT_TAIL(&pData->icmp_msg_head, icm, im_queue);
193	pData->cIcmpCacheSize++;
194
195	return icm;
196	}
197
198
199	static void
200	icmp_attach(PNATState pData, struct mbuf *m)
201	{
202	struct icmp_msg *icm;
203
204	#ifdef DEBUG
205	{
206	/* only used for ping */
207	struct ip ip = mtod(m, struct ip );
208	Assert(ip->ip_p == IPPROTO_ICMP);
209	}
210	#endif
211
212	icm = icmp_msg_alloc(pData);
213	if (RT_UNLIKELY(icm == NULL))
214	return;
215
216	icm->im_so = &pData->icmp_socket;
217	icm->im_m = m;
218	}
219
220
221	void
222	icmp_msg_delete(PNATState pData, struct icmp_msg *icm)
223	{
224	if (RT_UNLIKELY(icm == NULL))
225	return;
226
227	#ifdef DEBUG
228	{
229	struct icmp_msg *existing;
230	int iTally = 0;
231
232	TAILQ_FOREACH(existing, &pData->icmp_msg_head, im_queue)
233	++iTally;
234	Assert(pData->cIcmpCacheSize == iTally);
235
236	Assert(pData->cIcmpCacheSize > 0);
237	TAILQ_FOREACH(existing, &pData->icmp_msg_head, im_queue)
238	{
239	if (existing == icm)
240	break;
241	}
242	Assert(existing != NULL);
243	}
244	#endif
245
246	TAILQ_REMOVE(&pData->icmp_msg_head, icm, im_queue);
247	pData->cIcmpCacheSize--;
248
249	icm->im_so->so_m = NULL;
250	if (icm->im_m != NULL)
251	m_freem(pData, icm->im_m);
252
253	RTMemFree(icm);
254	}
255
256
257	/*
258	* ip here is ip header + 64bytes readed from ICMP packet
259	*/
260	struct icmp_msg *
261	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
262	{
263	struct mbuf *m0;
264	struct ip *ip0;
265	struct icmp icp, icp0;
266	struct icmp_msg *icm = NULL;
267	int found = 0;
268	struct udphdr *udp;
269	struct tcphdr *tcp;
270	struct socket *head_socket = NULL;
271	struct socket *last_socket = NULL;
272	struct socket *so = NULL;
273	struct in_addr faddr;
274	u_short lport, fport;
275
276	faddr.s_addr = ~0;
277
278	lport = ~0;
279	fport = ~0;
280
281
282	LogFlowFunc(("ENTER: ip->ip_p:%d\n", ip->ip_p));
283	switch (ip->ip_p)
284	{
285	case IPPROTO_ICMP:
286	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
287	TAILQ_FOREACH(icm, &pData->icmp_msg_head, im_queue)
288	{
289	m0 = icm->im_m;
290	ip0 = mtod(m0, struct ip *);
291	if (ip0->ip_p != IPPROTO_ICMP)
292	{
293	/* try next item */
294	continue;
295	}
296	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
297	/*
298	* IP could pointer to ICMP_REPLY datagram (1)
299	* or pointer IP header in ICMP payload in case of
300	* ICMP_TIMXCEED or ICMP_UNREACH (2)
301	*
302	* if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
303	* IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
304	*
305	* if (2) then check that payload ICMP has got type ICMP_ECHO and
306	* IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
307	* one was sent.
308	*/
309	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
310	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
311	&& icp->icmp_id == icp0->icmp_id
312	&& icp->icmp_seq == icp0->icmp_seq)
313	{
314	found = 1;
315	Log(("Have found %R[natsock]\n", icm->im_so));
316	break;
317	}
318	Log(("Have found nothing\n"));
319	}
320	break;
321
322	/*
323	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
324	* from which the IP package has been sent.
325	*/
326	case IPPROTO_UDP:
327	head_socket = &udb;
328	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
329	faddr.s_addr = ip->ip_dst.s_addr;
330	fport = udp->uh_dport;
331	lport = udp->uh_sport;
332	last_socket = udp_last_so;
333	/* fall through */
334
335	case IPPROTO_TCP:
336	if (head_socket == NULL)
337	{
338	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
339	head_socket = &tcb; /* head_socket could be initialized with udb*/
340	faddr.s_addr = ip->ip_dst.s_addr;
341	fport = tcp->th_dport;
342	lport = tcp->th_sport;
343	last_socket = tcp_last_so;
344	}
345	/* check last socket first */
346	if ( last_socket->so_faddr.s_addr == faddr.s_addr
347	&& last_socket->so_fport == fport
348	&& last_socket->so_hlport == lport)
349	{
350	found = 1;
351	so = last_socket;
352	break;
353	}
354	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
355	{
356	/* Should be replaced by hash here */
357	Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n",
358	so, faddr.s_addr, ntohs(fport), ntohs(lport), ntohs(so->so_hlport)));
359	if ( so->so_faddr.s_addr == faddr.s_addr
360	&& so->so_fport == fport
361	&& so->so_hlport == lport)
362	{
363	found = 1;
364	break;
365	}
366	}
367	break;
368
369	default:
370	Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
371	}
372
373	#ifdef DEBUG
374	if (found)
375	Assert((icm != NULL) ^ (so != NULL));
376	#endif
377
378	if (found && icm == NULL)
379	{
380	/*
381	* XXX: Implies this is not a pong, found socket. This is, of
382	* course, wasteful since the caller will delete icmp_msg
383	* immediately after processing, so there's not much reason to
384	* clutter up the queue with it.
385	*/
386	AssertReturn(so != NULL, NULL);
387
388	/*
389	* XXX: FIXME: If the very first send(2) fails, the socket is
390	* still in SS_NOFDREF and so we will not report this too.
391	*/
392	if (so->so_state == SS_NOFDREF)
393	{
394	/* socket is shutting down we've already sent ICMP on it. */
395	Log(("NAT:ICMP: disconnected %R[natsock]\n", so));
396	LogFlowFunc(("LEAVE: icm:NULL\n"));
397	return NULL;
398	}
399
400	if (so->so_m == NULL)
401	{
402	Log(("NAT:ICMP: no saved mbuf for %R[natsock]\n", so));
403	LogFlowFunc(("LEAVE: icm:NULL\n"));
404	return NULL;
405	}
406
407	icm = icmp_msg_alloc(pData);
408	if (RT_UNLIKELY(icm == NULL))
409	{
410	LogFlowFunc(("LEAVE: icm:NULL\n"));
411	return NULL;
412	}
413
414	Log(("NAT:ICMP: for %R[natsock]\n", so));
415	icm->im_so = so;
416	icm->im_m = so->so_m;
417	}
418	LogFlowFunc(("LEAVE: icm:%p\n", icm));
419	return icm;
420	}
421	#endif /* !RT_OS_WINDOWS */
422
423
424	/*
425	* Process a received ICMP message.
426	*/
427	void
428	icmp_input(PNATState pData, struct mbuf *m, int hlen)
429	{
430	register struct ip ip = mtod(m, struct ip );
431	int icmplen = ip->ip_len;
432	uint8_t icmp_type;
433	void *icp_buf = NULL;
434	uint32_t dst;
435
436	/* int code; */
437
438	LogFlowFunc(("ENTER: m = %lx, m_len = %d\n", (long)m, m ? m->m_len : 0));
439
440	icmpstat.icps_received++;
441
442	/*
443	* Locate icmp structure in mbuf, and check
444	* that its not corrupted and of at least minimum length.
445	*/
446	if (icmplen < ICMP_MINLEN)
447	{
448	/* min 8 bytes payload */
449	icmpstat.icps_tooshort++;
450	goto end_error_free_m;
451	}
452
453	m->m_len -= hlen;
454	m->m_data += hlen;
455
456	if (cksum(m, icmplen))
457	{
458	icmpstat.icps_checksum++;
459	goto end_error_free_m;
460	}
461
462	/* are we guaranteed to have ICMP header in first mbuf? be safe. */
463	m_copydata(m, 0, sizeof(icmp_type), (caddr_t)&icmp_type);
464
465	m->m_len += hlen;
466	m->m_data -= hlen;
467
468	/* icmpstat.icps_inhist[icp->icmp_type]++; */
469	/* code = icp->icmp_code; */
470
471	LogFlow(("icmp_type = %d\n", icmp_type));
472	switch (icmp_type)
473	{
474	case ICMP_ECHO:
475	ip->ip_len += hlen; /* since ip_input subtracts this */
476	dst = ip->ip_dst.s_addr;
477	if ( CTL_CHECK(dst, CTL_ALIAS)
478	\|\| CTL_CHECK(dst, CTL_DNS)
479	\|\| CTL_CHECK(dst, CTL_TFTP))
480	{
481	uint8_t echo_reply = ICMP_ECHOREPLY;
482	m_copyback(pData, m, hlen + RT_OFFSETOF(struct icmp, icmp_type),
483	sizeof(echo_reply), (caddr_t)&echo_reply);
484	ip->ip_dst.s_addr = ip->ip_src.s_addr;
485	ip->ip_src.s_addr = dst;
486	icmp_reflect(pData, m);
487	goto done;
488	}
489
490	#ifdef RT_OS_WINDOWS
491	{
492	icmpwin_ping(pData, m, hlen);
493	break; /* free mbuf */
494	}
495	#else
496	{
497	struct icmp *icp;
498	struct sockaddr_in addr;
499
500	/* XXX: FIXME: this is bogus, see CTL_CHECKs above */
501	addr.sin_family = AF_INET;
502	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
503	{
504	/* It's an alias */
505	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
506	{
507	case CTL_DNS:
508	case CTL_ALIAS:
509	default:
510	addr.sin_addr = loopback_addr;
511	break;
512	}
513	}
514	else
515	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
516
517	if (m->m_next)
518	{
519	icp_buf = RTMemAlloc(icmplen);
520	if (!icp_buf)
521	{
522	Log(("NAT: not enought memory to allocate the buffer\n"));
523	goto end_error_free_m;
524	}
525	m_copydata(m, hlen, icmplen, icp_buf);
526	icp = (struct icmp *)icp_buf;
527	}
528	else
529	icp = (struct icmp )(mtod(m, char ) + hlen);
530
531	if (pData->icmp_socket.s != -1)
532	{
533	static bool fIcmpSocketErrorReported;
534	int ttl;
535	int status;
536	ssize_t rc;
537
538	ttl = ip->ip_ttl;
539	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
540	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
541	(void *)&ttl, sizeof(ttl));
542	if (status < 0)
543	Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
544	strerror(errno)));
545	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
546	(struct sockaddr *)&addr, sizeof(addr));
547	if (rc >= 0)
548	{
549	icmp_attach(pData, m);
550	/* don't let m_freem at the end free atached buffer */
551	goto done;
552	}
553
554
555	if (!fIcmpSocketErrorReported)
556	{
557	LogRel(("NAT: icmp_input udp sendto tx errno = %d (%s)\n",
558	errno, strerror(errno)));
559	fIcmpSocketErrorReported = true;
560	}
561	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
562	}
563	}
564	#endif /* !RT_OS_WINDOWS */
565	break;
566	case ICMP_UNREACH:
567	case ICMP_TIMXCEED:
568	/* @todo(vvl): both up cases comes from guest,
569	* indeed right solution would be find the socket
570	* corresponding to ICMP data and close it.
571	*/
572	case ICMP_PARAMPROB:
573	case ICMP_SOURCEQUENCH:
574	case ICMP_TSTAMP:
575	case ICMP_MASKREQ:
576	case ICMP_REDIRECT:
577	icmpstat.icps_notsupp++;
578	break;
579
580	default:
581	icmpstat.icps_badtype++;
582	} /* switch */
583
584	end_error_free_m:
585	m_freem(pData, m);
586
587	done:
588	if (icp_buf)
589	RTMemFree(icp_buf);
590	}
591
592
593	/**
594	* Send an ICMP message in response to a situation
595	*
596	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
597	* MUST NOT change this header information.
598	* MUST NOT reply to a multicast/broadcast IP address.
599	* MUST NOT reply to a multicast/broadcast MAC address.
600	* MUST reply to only the first fragment.
601	*
602	* Send ICMP_UNREACH back to the source regarding msrc.
603	* It is reported as the bad ip packet. The header should
604	* be fully correct and in host byte order.
605	* ICMP fragmentation is illegal.
606	*
607	* @note: implementation note: MSIZE is 256 bytes (minimal buffer).
608	* We always truncate original payload to 8 bytes required by the RFC,
609	* so the largest possible datagram is 14 (ethernet) + 20 (ip) +
610	* 8 (icmp) + 60 (max original ip with options) + 8 (original payload)
611	* = 110 bytes which fits into sinlge mbuf.
612	*
613	* @note This function will free msrc!
614	*/
615
616	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
617	{
618	unsigned ohlen, olen;
619	struct mbuf *m;
620	struct ip oip, ip;
621	struct icmp *icp;
622	void *payload;
623	RT_NOREF(minsize);
624
625	LogFlow(("icmp_error: msrc = %p, msrc_len = %d\n",
626	(void *)msrc, msrc ? msrc->m_len : 0));
627
628	if (RT_UNLIKELY(msrc == NULL))
629	goto end_error;
630
631	M_ASSERTPKTHDR(msrc);
632
633	if ( type != ICMP_UNREACH
634	&& type != ICMP_TIMXCEED
635	&& type != ICMP_SOURCEQUENCH)
636	goto end_error;
637
638	oip = mtod(msrc, struct ip *);
639	LogFunc(("msrc: %RTnaipv4 -> %RTnaipv4\n", oip->ip_src, oip->ip_dst));
640
641	if (oip->ip_src.s_addr == INADDR_ANY)
642	goto end_error;
643
644	if (oip->ip_off & IP_OFFMASK)
645	goto end_error; /* Only reply to fragment 0 */
646
647	ohlen = oip->ip_hl * 4;
648	AssertStmt(ohlen >= sizeof(struct ip), goto end_error);
649
650	olen = oip->ip_len;
651	AssertStmt(olen >= ohlen, goto end_error);
652
653	if (oip->ip_p == IPPROTO_ICMP)
654	{
655	struct icmp oicp = (struct icmp )((char *)oip + ohlen);
656	/*
657	* Assume any unknown ICMP type is an error. This isn't
658	* specified by the RFC, but think about it..
659	*/
660	if (oicp->icmp_type > ICMP_MAXTYPE \|\| icmp_flush[oicp->icmp_type])
661	goto end_error;
662	}
663
664	/* undo byte order conversions done in ip_input() */
665	HTONS(oip->ip_len);
666	HTONS(oip->ip_id);
667	HTONS(oip->ip_off);
668
669	m = m_gethdr(pData, M_NOWAIT, MT_HEADER);
670	if (RT_UNLIKELY(m == NULL))
671	goto end_error;
672
673	m->m_flags \|= M_SKIP_FIREWALL;
674	m->m_data += if_maxlinkhdr;
675
676	ip = mtod(m, struct ip *);
677	m->m_pkthdr.header = (void *)ip;
678
679	/* fill in ip (ip_output0() does the boilerplate for us) */
680	ip->ip_tos = ((oip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
681	/* ip->ip_len will be set later */
682	ip->ip_off = 0;
683	ip->ip_ttl = MAXTTL;
684	ip->ip_p = IPPROTO_ICMP;
685	ip->ip_src = alias_addr;
686	ip->ip_dst = oip->ip_src;
687
688	/* fill in icmp */
689	icp = (struct icmp )((char )ip + sizeof(*ip));
690	icp->icmp_type = type;
691	icp->icmp_code = code;
692	icp->icmp_id = 0;
693	icp->icmp_seq = 0;
694
695	/* fill in icmp payload: original ip header plus 8 bytes of its payload */
696	if (olen > ohlen + 8)
697	olen = ohlen + 8;
698	payload = (void )((char )icp + ICMP_MINLEN);
699	memcpy(payload, oip, olen);
700
701	/*
702	* Original code appended this message after the payload. This
703	* might have been a good idea for real slirp, as it provided a
704	* communication channel with the remote host. But 90s are over.
705	*/
706	NOREF(message);
707
708	/* hide ip header for icmp checksum calculation */
709	m->m_data += sizeof(struct ip);
710	m->m_len = ICMP_MINLEN + /* truncated */ olen;
711
712	icp->icmp_cksum = 0;
713	icp->icmp_cksum = cksum(m, m->m_len);
714
715	/* reveal ip header */
716	m->m_data -= sizeof(struct ip);
717	m->m_len += sizeof(struct ip);
718	ip->ip_len = m->m_len;
719
720	(void) ip_output0(pData, (struct socket *)NULL, m, 1);
721
722	icmpstat.icps_reflect++;
723
724	/* clear source datagramm in positive branch */
725	m_freem(pData, msrc);
726	LogFlowFuncLeave();
727	return;
728
729	end_error:
730
731	/*
732	* clear source datagramm in case if some of requirement haven't been met.
733	*/
734	if (msrc)
735	m_freem(pData, msrc);
736
737	{
738	static bool fIcmpErrorReported;
739	if (!fIcmpErrorReported)
740	{
741	LogRel(("NAT: Error occurred while sending ICMP error message\n"));
742	fIcmpErrorReported = true;
743	}
744	}
745	LogFlowFuncLeave();
746	}
747
748	/*
749	* Reflect the ip packet back to the source
750	* Note: m isn't duplicated by this method and more delivered to ip_output then.
751	*/
752	void
753	icmp_reflect(PNATState pData, struct mbuf *m)
754	{
755	register struct ip ip = mtod(m, struct ip );
756	int hlen = ip->ip_hl << 2;
757	register struct icmp *icp;
758	LogFlowFunc(("ENTER: m:%p\n", m));
759
760	/*
761	* Send an icmp packet back to the ip level,
762	* after supplying a checksum.
763	*/
764	m->m_data += hlen;
765	m->m_len -= hlen;
766	icp = mtod(m, struct icmp *);
767
768	icp->icmp_cksum = 0;
769	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
770
771	m->m_data -= hlen;
772	m->m_len += hlen;
773
774	(void) ip_output(pData, (struct socket *)NULL, m);
775
776	icmpstat.icps_reflect++;
777	LogFlowFuncLeave();
778	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 63012

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