bootp.c@ 39409

Last change on this file since 39409 was 39409, checked in by vboxsync, 13 years ago
NAT: warnings + NAT/netservice fixes.
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File size: 27.6 KB

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1	/* $Id: bootp.c 39409 2011-11-24 15:28:32Z vboxsync $ */
2	/** @file
3	* NAT - BOOTP/DHCP server emulation.
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	* QEMU BOOTP/DHCP server
22	*
23	* Copyright (c) 2004 Fabrice Bellard
24	*
25	* Permission is hereby granted, free of charge, to any person obtaining a copy
26	* of this software and associated documentation files (the "Software"), to deal
27	* in the Software without restriction, including without limitation the rights
28	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
29	* copies of the Software, and to permit persons to whom the Software is
30	* furnished to do so, subject to the following conditions:
31	*
32	* The above copyright notice and this permission notice shall be included in
33	* all copies or substantial portions of the Software.
34	*
35	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
36	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
37	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
38	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
39	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
40	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
41	* THE SOFTWARE.
42	*/
43	#include <slirp.h>
44
45	/** Entry in the table of known DHCP clients. */
46	typedef struct
47	{
48	uint32_t xid;
49	bool allocated;
50	uint8_t macaddr[6];
51	struct in_addr addr;
52	int number;
53	} BOOTPClient;
54	/** Number of DHCP clients supported by NAT. */
55	#define NB_ADDR 16
56
57	#define bootp_clients ((BOOTPClient *)pData->pbootp_clients)
58
59	/* XXX: only DHCP is supported */
60	static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
61
62	static void bootp_reply(PNATState pData, struct mbuf *m0, int offReply, uint16_t flags);
63
64	static uint8_t dhcp_find_option(uint8_t vend, uint8_t tag)
65	{
66	uint8_t *q = vend;
67	uint8_t len;
68	/@todo magic validation /
69	q += 4; /magic/
70	while(*q != RFC1533_END)
71	{
72	if (*q == RFC1533_PAD)
73	continue;
74	if (*q == tag)
75	return q;
76	q++;
77	len = *q;
78	q += 1 + len;
79	}
80	return NULL;
81	}
82
83	static BOOTPClient *bc_alloc_client(PNATState pData)
84	{
85	int i;
86	for (i = 0; i < NB_ADDR; i++)
87	{
88	if (!bootp_clients[i].allocated)
89	{
90	BOOTPClient *bc;
91
92	bc = &bootp_clients[i];
93	memset(bc, 0, sizeof(BOOTPClient));
94	bc->allocated = 1;
95	bc->number = i;
96	return bc;
97	}
98	}
99	return NULL;
100	}
101
102	static BOOTPClient get_new_addr(PNATState pData, struct in_addr paddr)
103	{
104	BOOTPClient *bc;
105	bc = bc_alloc_client(pData);
106	if (!bc)
107	return NULL;
108
109	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (bc->number + START_ADDR));
110	bc->addr.s_addr = paddr->s_addr;
111	return bc;
112	}
113
114	static int release_addr(PNATState pData, struct in_addr *paddr)
115	{
116	unsigned i;
117	for (i = 0; i < NB_ADDR; i++)
118	{
119	if (paddr->s_addr == bootp_clients[i].addr.s_addr)
120	{
121	memset(&bootp_clients[i], 0, sizeof(BOOTPClient));
122	return VINF_SUCCESS;
123	}
124	}
125	return VERR_NOT_FOUND;
126	}
127
128	/*
129	* from RFC 2131 4.3.1
130	* Field DHCPOFFER DHCPACK DHCPNAK
131	* ----- --------- ------- -------
132	* 'op' BOOTREPLY BOOTREPLY BOOTREPLY
133	* 'htype' (From "Assigned Numbers" RFC)
134	* 'hlen' (Hardware address length in octets)
135	* 'hops' 0 0 0
136	* 'xid' 'xid' from client 'xid' from client 'xid' from client
137	* DHCPDISCOVER DHCPREQUEST DHCPREQUEST
138	* message message message
139	* 'secs' 0 0 0
140	* 'ciaddr' 0 'ciaddr' from 0
141	* DHCPREQUEST or 0
142	* 'yiaddr' IP address offered IP address 0
143	* to client assigned to client
144	* 'siaddr' IP address of next IP address of next 0
145	* bootstrap server bootstrap server
146	* 'flags' 'flags' from 'flags' from 'flags' from
147	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
148	* message message message
149	* 'giaddr' 'giaddr' from 'giaddr' from 'giaddr' from
150	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
151	* message message message
152	* 'chaddr' 'chaddr' from 'chaddr' from 'chaddr' from
153	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
154	* message message message
155	* 'sname' Server host name Server host name (unused)
156	* or options or options
157	* 'file' Client boot file Client boot file (unused)
158	* name or options name or options
159	* 'options' options options
160	*
161	* Option DHCPOFFER DHCPACK DHCPNAK
162	* ------ --------- ------- -------
163	* Requested IP address MUST NOT MUST NOT MUST NOT
164	* IP address lease time MUST MUST (DHCPREQUEST) MUST NOT
165	* MUST NOT (DHCPINFORM)
166	* Use 'file'/'sname' fields MAY MAY MUST NOT
167	* DHCP message type DHCPOFFER DHCPACK DHCPNAK
168	* Parameter request list MUST NOT MUST NOT MUST NOT
169	* Message SHOULD SHOULD SHOULD
170	* Client identifier MUST NOT MUST NOT MAY
171	* Vendor class identifier MAY MAY MAY
172	* Server identifier MUST MUST MUST
173	* Maximum message size MUST NOT MUST NOT MUST NOT
174	* All others MAY MAY MUST NOT
175	*/
176	static BOOTPClient find_addr(PNATState pData, struct in_addr paddr, const uint8_t *macaddr)
177	{
178	int i;
179
180	for (i = 0; i < NB_ADDR; i++)
181	{
182	if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
183	{
184	BOOTPClient *bc;
185
186	bc = &bootp_clients[i];
187	bc->allocated = 1;
188	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (i + START_ADDR));
189	return bc;
190	}
191	}
192	return NULL;
193	}
194
195	static struct mbuf dhcp_create_msg(PNATState pData, struct bootp_t bp, struct mbuf *m, uint8_t type)
196	{
197	struct bootp_t *rbp;
198	struct ethhdr *eh;
199	uint8_t *q;
200
201	eh = mtod(m, struct ethhdr *);
202	memcpy(eh->h_source, bp->bp_hwaddr, ETH_ALEN); /* XXX: if_encap just swap source with dest */
203
204	m->m_data += if_maxlinkhdr; /reserve ether header /
205
206	rbp = mtod(m, struct bootp_t *);
207	memset(rbp, 0, sizeof(struct bootp_t));
208	rbp->bp_op = BOOTP_REPLY;
209	rbp->bp_xid = bp->bp_xid; /* see table 3 of rfc2131*/
210	rbp->bp_flags = bp->bp_flags; /* figure 2 of rfc2131 */
211	rbp->bp_giaddr.s_addr = bp->bp_giaddr.s_addr;
212	#if 0 /check flags/
213	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
214	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
215	#endif
216	rbp->bp_htype = 1;
217	rbp->bp_hlen = 6;
218	memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
219
220	memcpy(rbp->bp_vend, rfc1533_cookie, 4); /* cookie */
221	q = rbp->bp_vend;
222	q += 4;
223	*q++ = RFC2132_MSG_TYPE;
224	*q++ = 1;
225	*q++ = type;
226
227	return m;
228	}
229
230	static int dhcp_do_ack_offer(PNATState pData, struct mbuf m, BOOTPClient bc, int fDhcpRequest)
231	{
232	struct bootp_t *rbp = NULL;
233	uint8_t *q;
234	struct in_addr saddr;
235	int val;
236
237	struct dns_entry *de = NULL;
238	struct dns_domain_entry *dd = NULL;
239	int added = 0;
240	uint8_t *q_dns_header = NULL;
241	uint32_t lease_time = RT_H2N_U32_C(LEASE_TIME);
242	uint32_t netmask = RT_H2N_U32(pData->netmask);
243
244	rbp = mtod(m, struct bootp_t *);
245	q = &rbp->bp_vend[0];
246	q += 7; /* !cookie rfc 2132 + TYPE*/
247
248	/DHCP Offer specific/
249	/*
250	* we're care in built-in tftp server about existence/validness of the boot file.
251	*/
252	if (bootp_filename)
253	RTStrPrintf((char*)rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
254
255	Log(("NAT: DHCP: bp_file:%s\n", &rbp->bp_file));
256	/* Address/port of the DHCP server. */
257	rbp->bp_yiaddr = bc->addr; /* Client IP address */
258	Log(("NAT: DHCP: bp_yiaddr:%RTnaipv4\n", rbp->bp_yiaddr));
259	rbp->bp_siaddr = pData->tftp_server; /* Next Server IP address, i.e. TFTP */
260	Log(("NAT: DHCP: bp_siaddr:%RTnaipv4\n", rbp->bp_siaddr));
261	if (fDhcpRequest)
262	{
263	rbp->bp_ciaddr.s_addr = bc->addr.s_addr; /* Client IP address */
264	}
265	saddr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
266	Log(("NAT: DHCP: s_addr:%RTnaipv4\n", saddr));
267
268	#define FILL_BOOTP_EXT(q, tag, len, pvalue) \
269	do { \
270	struct bootp_ext be = (struct bootp_ext )(q); \
271	be->bpe_tag = (tag); \
272	be->bpe_len = (len); \
273	memcpy(&be[1], (pvalue), (len)); \
274	(q) = (uint8_t *)(&be[1]) + (len); \
275	}while(0)
276	/* appending another value to tag, calculates len of whole block*/
277	#define FILL_BOOTP_APP(head, q, tag, len, pvalue) \
278	do { \
279	struct bootp_ext be = (struct bootp_ext )(head); \
280	memcpy(q, (pvalue), (len)); \
281	(q) += (len); \
282	Assert(be->bpe_tag == (tag)); \
283	be->bpe_len += (len); \
284	}while(0)
285
286
287	FILL_BOOTP_EXT(q, RFC1533_NETMASK, 4, &netmask);
288	FILL_BOOTP_EXT(q, RFC1533_GATEWAY, 4, &saddr);
289
290	if (pData->fUseDnsProxy \|\| pData->fUseHostResolver)
291	{
292	uint32_t addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_DNS);
293	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &addr);
294	goto skip_dns_servers;
295	}
296
297	if (!TAILQ_EMPTY(&pData->pDnsList))
298	{
299	de = TAILQ_LAST(&pData->pDnsList, dns_list_head);
300	q_dns_header = q;
301	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &de->de_addr.s_addr);
302	}
303
304	TAILQ_FOREACH_REVERSE(de, &pData->pDnsList, dns_list_head, de_list)
305	{
306	if (TAILQ_LAST(&pData->pDnsList, dns_list_head) == de)
307	continue; /* first value with head we've ingected before */
308	FILL_BOOTP_APP(q_dns_header, q, RFC1533_DNS, 4, &de->de_addr.s_addr);
309	}
310
311	skip_dns_servers:
312	if (pData->fPassDomain && !pData->fUseHostResolver)
313	{
314	LIST_FOREACH(dd, &pData->pDomainList, dd_list)
315	{
316
317	if (dd->dd_pszDomain == NULL)
318	continue;
319	/* never meet valid separator here in RFC1533*/
320	if (added != 0)
321	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, ",");
322	else
323	added = 1;
324	val = (int)strlen(dd->dd_pszDomain);
325	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, dd->dd_pszDomain);
326	}
327	}
328
329	FILL_BOOTP_EXT(q, RFC2132_LEASE_TIME, 4, &lease_time);
330
331	if (*slirp_hostname)
332	{
333	val = (int)strlen(slirp_hostname);
334	FILL_BOOTP_EXT(q, RFC1533_HOSTNAME, val, slirp_hostname);
335	}
336	slirp_arp_cache_update_or_add(pData, rbp->bp_yiaddr.s_addr, bc->macaddr);
337	return q - rbp->bp_vend; /return offset /
338	}
339
340	static int dhcp_send_nack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
341	{
342	struct bootp_t *rbp;
343	rbp = mtod(m, struct bootp_t *);
344	NOREF(bc);
345
346	dhcp_create_msg(pData, bp, m, DHCPNAK);
347	return 7;
348	}
349
350	static int dhcp_send_ack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m, int fDhcpRequest)
351	{
352	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
353
354	dhcp_create_msg(pData, bp, m, DHCPACK);
355	offReply = dhcp_do_ack_offer(pData, m, bc, fDhcpRequest);
356	return offReply;
357	}
358
359	static int dhcp_send_offer(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
360	{
361	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
362
363	dhcp_create_msg(pData, bp, m, DHCPOFFER);
364	offReply = dhcp_do_ack_offer(pData, m, bc, /* fDhcpRequest=*/ 0);
365	return offReply;
366	}
367
368	/**
369	* decoding client messages RFC2131 (4.3.6)
370	* ---------------------------------------------------------------------
371	* \| \|INIT-REBOOT \|SELECTING \|RENEWING \|REBINDING \|
372	* ---------------------------------------------------------------------
373	* \|broad/unicast \|broadcast \|broadcast \|unicast \|broadcast \|
374	* \|server-ip \|MUST NOT \|MUST \|MUST NOT \|MUST NOT \|
375	* \|requested-ip \|MUST \|MUST \|MUST NOT \|MUST NOT \|
376	* \|ciaddr \|zero \|zero \|IP address \|IP address\|
377	* ---------------------------------------------------------------------
378	*
379	*/
380
381	enum DHCP_REQUEST_STATES
382	{
383	INIT_REBOOT,
384	SELECTING,
385	RENEWING,
386	REBINDING,
387	NONE
388	};
389
390	static int dhcp_decode_request(PNATState pData, struct bootp_t bp, struct mbuf m)
391	{
392	BOOTPClient *bc = NULL;
393	struct in_addr daddr;
394	int offReply;
395	uint8_t *req_ip = NULL;
396	uint8_t *server_ip = NULL;
397	uint32_t ui32;
398	enum DHCP_REQUEST_STATES dhcp_stat = NONE;
399
400	/* need to understand which type of request we get */
401	req_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
402	server_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_SRV_ID);
403	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
404
405	if (server_ip != NULL)
406	{
407	/* selecting */
408	if (!bc)
409	{
410	LogRel(("NAT: DHCP no IP was allocated\n"));
411	return -1;
412	}
413
414	dhcp_stat = SELECTING;
415	Assert((bp->bp_ciaddr.s_addr == INADDR_ANY));
416	Assert(((uint32_t )(req_ip + 2) == bc->addr.s_addr)); /the same address as in offer/
417	#if 0
418	/* DSL xid in request differ from offer */
419	Assert((bp->bp_xid == bc->xid));
420	#endif
421	}
422	else
423	{
424	if (req_ip != NULL)
425	{
426	/* init-reboot */
427	dhcp_stat = INIT_REBOOT;
428	}
429	else
430	{
431	/* table 4 of rfc2131 */
432	if (bp->bp_flags & RT_H2N_U16_C(DHCP_FLAGS_B))
433	dhcp_stat = REBINDING;
434	else
435	dhcp_stat = RENEWING;
436	}
437	}
438
439	/?? renewing ??/
440	switch (dhcp_stat)
441	{
442	case RENEWING:
443	Assert((server_ip == NULL && req_ip == NULL && bp->bp_ciaddr.s_addr != INADDR_ANY));
444	if (bc != NULL)
445	{
446	Assert((bc->addr.s_addr == bp->bp_ciaddr.s_addr));
447	/if it already here well just do ack, we aren't aware of dhcp time expiration/
448	}
449	else
450	{
451	if ((bp->bp_ciaddr.s_addr & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
452	{
453	LogRel(("NAT: Client %RTnaipv4 requested IP -- sending NAK\n", bp->bp_ciaddr));
454	offReply = dhcp_send_nack(pData, bp, bc, m);
455	return offReply;
456	}
457
458	bc = bc_alloc_client(pData);
459	if (!bc)
460	{
461	LogRel(("NAT: can't alloc address. RENEW has been silently ignored.\n"));
462	return -1;
463	}
464
465	Assert((bp->bp_hlen == ETH_ALEN));
466	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
467	bc->addr.s_addr = bp->bp_ciaddr.s_addr;
468	}
469	break;
470
471	case INIT_REBOOT:
472	Assert(server_ip == NULL);
473	Assert(req_ip != NULL);
474	ui32 = (uint32_t )(req_ip + 2);
475	if ((ui32 & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
476	{
477	LogRel(("NAT: address %RTnaipv4 has been requested -- sending NAK\n", ui32));
478	offReply = dhcp_send_nack(pData, bp, bc, m);
479	return offReply;
480	}
481
482	bc = bc_alloc_client(pData);
483	if (!bc)
484	{
485	LogRel(("NAT: can't alloc address. RENEW has been silently ignored\n"));
486	return -1;
487	}
488	Assert((bp->bp_hlen == ETH_ALEN));
489	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
490	bc->addr.s_addr = ui32;
491	break;
492
493	case NONE:
494	Assert((dhcp_stat != NONE));
495	return -1;
496
497	default:
498	break;
499	}
500
501	LogRel(("NAT: DHCP offered IP address %RTnaipv4\n", bc->addr));
502	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 1);
503	return offReply;
504	}
505
506	static int dhcp_decode_discover(PNATState pData, struct bootp_t bp, int fDhcpDiscover, struct mbuf m)
507	{
508	BOOTPClient *bc;
509	struct in_addr daddr;
510	int offReply;
511
512	if (fDhcpDiscover)
513	{
514	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
515	if (!bc)
516	{
517	bc = get_new_addr(pData, &daddr);
518	if (!bc)
519	{
520	LogRel(("NAT: DHCP no IP address left\n"));
521	Log(("no address left\n"));
522	return -1;
523	}
524	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
525	}
526
527	bc->xid = bp->bp_xid;
528	LogRel(("NAT: DHCP offered IP address %RTnaipv4\n", bc->addr));
529	offReply = dhcp_send_offer(pData, bp, bc, m);
530	return offReply;
531	}
532	else
533	{
534	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
535	if (!bc)
536	{
537	LogRel(("NAT: DHCP Inform was ignored no boot client was found\n"));
538	return -1;
539	}
540
541	LogRel(("NAT: DHCP offered IP address %RTnaipv4\n", bc->addr));
542	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 0);
543	return offReply;
544	}
545
546	return -1;
547	}
548
549	static int dhcp_decode_release(PNATState pData, struct bootp_t *bp)
550	{
551	int rc = release_addr(pData, &bp->bp_ciaddr);
552	LogRel(("NAT: %s %RTnaipv4\n",
553	RT_SUCCESS(rc) ? "DHCP released IP address" : "Ignored DHCP release for IP address",
554	&bp->bp_ciaddr));
555	return 0;
556	}
557	/**
558	* fields for discovering t
559	* Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE,
560	* DHCPINFORM DHCPRELEASE
561	* ----- ------------ ----------- -----------
562	* 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST
563	* 'htype' (From "Assigned Numbers" RFC)
564	* 'hlen' (Hardware address length in octets)
565	* 'hops' 0 0 0
566	* 'xid' selected by client 'xid' from server selected by
567	* DHCPOFFER message client
568	* 'secs' 0 or seconds since 0 or seconds since 0
569	* DHCP process started DHCP process started
570	* 'flags' Set 'BROADCAST' Set 'BROADCAST' 0
571	* flag if client flag if client
572	* requires broadcast requires broadcast
573	* reply reply
574	* 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE)
575	* client's network address client's network
576	* network address (BOUND/RENEW/REBIND) address
577	* (DHCPINFORM) (DHCPRELEASE)
578	* 'yiaddr' 0 0 0
579	* 'siaddr' 0 0 0
580	* 'giaddr' 0 0 0
581	* 'chaddr' client's hardware client's hardware client's hardware
582	* address address address
583	* 'sname' options, if options, if (unused)
584	* indicated in indicated in
585	* 'sname/file' 'sname/file'
586	* option; otherwise option; otherwise
587	* unused unused
588	* 'file' options, if options, if (unused)
589	* indicated in indicated in
590	* 'sname/file' 'sname/file'
591	* option; otherwise option; otherwise
592	* unused unused
593	* 'options' options options (unused)
594	* Requested IP address MAY MUST (in MUST
595	* (DISCOVER) SELECTING or (DHCPDECLINE),
596	* MUST NOT INIT-REBOOT) MUST NOT
597	* (INFORM) MUST NOT (in (DHCPRELEASE)
598	* BOUND or
599	* RENEWING)
600	* IP address lease time MAY MAY MUST NOT
601	* (DISCOVER)
602	* MUST NOT
603	* (INFORM)
604	* Use 'file'/'sname' fields MAY MAY MAY
605	* DHCP message type DHCPDISCOVER/ DHCPREQUEST DHCPDECLINE/
606	* DHCPINFORM DHCPRELEASE
607	* Client identifier MAY MAY MAY
608	* Vendor class identifier MAY MAY MUST NOT
609	* Server identifier MUST NOT MUST (after MUST
610	* SELECTING)
611	* MUST NOT (after
612	* INIT-REBOOT,
613	* BOUND, RENEWING
614	* or REBINDING)
615	* Parameter request list MAY MAY MUST NOT
616	* Maximum message size MAY MAY MUST NOT
617	* Message SHOULD NOT SHOULD NOT SHOULD
618	* Site-specific MAY MAY MUST NOT
619	* All others MAY MAY MUST NOT
620	*
621	*/
622	static void dhcp_decode(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
623	{
624	const uint8_t p, p_end;
625	int rc;
626	int pmsg_type;
627	struct in_addr req_ip;
628	int fDhcpDiscover = 0;
629	uint8_t *parameter_list = NULL;
630	struct mbuf *m = NULL;
631
632	pmsg_type = 0;
633	p = buf;
634	p_end = buf + size;
635	if (size < 5)
636	return;
637
638	if (memcmp(p, rfc1533_cookie, 4) != 0)
639	return;
640
641	p = dhcp_find_option(bp->bp_vend, RFC2132_MSG_TYPE);
642	Assert(p);
643	if (!p)
644	return;
645	/*
646	* We're going update dns list at least once per DHCP transaction (!not on every operation
647	* within transaction), assuming that transaction can't be longer than 1 min.
648	*/
649	if ( !pData->fUseHostResolver
650	&& ( pData->dnsLastUpdate == 0
651	\|\| curtime - pData->dnsLastUpdate > 60 * 1000)) /* one minute*/
652	{
653	uint8_t i = 2; /* i = 0 - tag, i == 1 - length */
654	parameter_list = dhcp_find_option(&bp->bp_vend[0], RFC2132_PARAM_LIST);
655	for (;parameter_list && i < parameter_list[1]; ++i)
656	{
657	if (parameter_list[i] == RFC1533_DNS)
658	{
659	slirp_release_dns_list(pData);
660	slirp_init_dns_list(pData);
661	pData->dnsLastUpdate = curtime;
662	break;
663	}
664	}
665	}
666
667	m = m_getcl(pData, M_DONTWAIT, MT_HEADER, M_PKTHDR);
668	if (!m)
669	{
670	LogRel(("NAT: can't alocate memory for response!\n"));
671	return;
672	}
673
674	switch (*(p+2))
675	{
676	case DHCPDISCOVER:
677	fDhcpDiscover = 1;
678	/* fall through */
679	case DHCPINFORM:
680	rc = dhcp_decode_discover(pData, bp, fDhcpDiscover, m);
681	if (rc > 0)
682	goto reply;
683	break;
684
685	case DHCPREQUEST:
686	rc = dhcp_decode_request(pData, bp, m);
687	if (rc > 0)
688	goto reply;
689	break;
690
691	case DHCPRELEASE:
692	rc = dhcp_decode_release(pData, bp);
693	/* no reply required */
694	break;
695
696	case DHCPDECLINE:
697	p = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
698	req_ip.s_addr = (uint32_t )(p + 2);
699	rc = bootp_cache_lookup_ether_by_ip(pData, req_ip.s_addr, NULL);
700	if (RT_FAILURE(rc))
701	{
702	/* Not registered */
703	BOOTPClient *bc;
704	bc = bc_alloc_client(pData);
705	Assert(bc);
706	bc->addr.s_addr = req_ip.s_addr;
707	slirp_arp_who_has(pData, bc->addr.s_addr);
708	LogRel(("NAT: %RTnaipv4 has been already registered\n", req_ip));
709	}
710	/* no response required */
711	break;
712
713	default:
714	AssertMsgFailed(("unsupported DHCP message type"));
715	}
716	/* silently ignore */
717	m_freem(pData, m);
718	return;
719
720	reply:
721	bootp_reply(pData, m, rc, bp->bp_flags);
722	}
723
724	static void bootp_reply(PNATState pData, struct mbuf *m, int offReply, uint16_t flags)
725	{
726	struct sockaddr_in saddr, daddr;
727	struct bootp_t *rbp = NULL;
728	uint8_t *q = NULL;
729	int nack;
730	rbp = mtod(m, struct bootp_t *);
731	Assert((m));
732	Assert((rbp));
733	q = rbp->bp_vend;
734	nack = (q[6] == DHCPNAK);
735	q += offReply;
736
737	saddr.sin_addr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
738
739	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
740
741	q++ = RFC1533_END; / end of message */
742
743	m->m_pkthdr.header = mtod(m, void *);
744	m->m_len = sizeof(struct bootp_t)
745	- sizeof(struct ip)
746	- sizeof(struct udphdr);
747	m->m_data += sizeof(struct udphdr)
748	+ sizeof(struct ip);
749	if ( (flags & RT_H2N_U16_C(DHCP_FLAGS_B))
750	\|\| nack != 0)
751	daddr.sin_addr.s_addr = INADDR_BROADCAST;
752	else
753	daddr.sin_addr.s_addr = rbp->bp_yiaddr.s_addr; /unicast requested by client/
754	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
755	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
756	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
757	}
758
759	void bootp_input(PNATState pData, struct mbuf *m)
760	{
761	struct bootp_t bp = mtod(m, struct bootp_t );
762
763	if (bp->bp_op == BOOTP_REQUEST)
764	dhcp_decode(pData, bp, bp->bp_vend, DHCP_OPT_LEN);
765	}
766
767	int bootp_cache_lookup_ip_by_ether(PNATState pData,const uint8_t* ether, uint32_t *pip)
768	{
769	int i;
770
771	if (!ether \|\| !pip)
772	return VERR_INVALID_PARAMETER;
773
774	for (i = 0; i < NB_ADDR; i++)
775	{
776	if ( bootp_clients[i].allocated
777	&& memcmp(bootp_clients[i].macaddr, ether, ETH_ALEN) == 0)
778	{
779	*pip = bootp_clients[i].addr.s_addr;
780	return VINF_SUCCESS;
781	}
782	}
783
784	*pip = INADDR_ANY;
785	return VERR_NOT_FOUND;
786	}
787
788	int bootp_cache_lookup_ether_by_ip(PNATState pData, uint32_t ip, uint8_t *ether)
789	{
790	int i;
791	for (i = 0; i < NB_ADDR; i++)
792	{
793	if ( bootp_clients[i].allocated
794	&& ip == bootp_clients[i].addr.s_addr)
795	{
796	if (ether != NULL)
797	memcpy(ether, bootp_clients[i].macaddr, ETH_ALEN);
798	return VINF_SUCCESS;
799	}
800	}
801
802	return VERR_NOT_FOUND;
803	}
804
805	/*
806	* Initialize dhcp server
807	* @returns 0 - if initialization is ok, non-zero otherwise
808	*/
809	int bootp_dhcp_init(PNATState pData)
810	{
811	pData->pbootp_clients = RTMemAllocZ(sizeof(BOOTPClient) * NB_ADDR);
812	if (!pData->pbootp_clients)
813	return VERR_NO_MEMORY;
814
815	return VINF_SUCCESS;
816	}
817
818	int bootp_dhcp_fini(PNATState pData)
819	{
820	if (pData->pbootp_clients != NULL)
821	RTMemFree(pData->pbootp_clients);
822
823	return VINF_SUCCESS;
824	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 39409

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