bootp.c@ 26817

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1	/*
2	* QEMU BOOTP/DHCP server
3	*
4	* Copyright (c) 2004 Fabrice Bellard
5	*
6	* Permission is hereby granted, free of charge, to any person obtaining a copy
7	* of this software and associated documentation files (the "Software"), to deal
8	* in the Software without restriction, including without limitation the rights
9	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10	* copies of the Software, and to permit persons to whom the Software is
11	* furnished to do so, subject to the following conditions:
12	*
13	* The above copyright notice and this permission notice shall be included in
14	* all copies or substantial portions of the Software.
15	*
16	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22	* THE SOFTWARE.
23	*/
24	#include <slirp.h>
25
26	/** Entry in the table of known DHCP clients. */
27	typedef struct
28	{
29	uint32_t xid;
30	bool allocated;
31	uint8_t macaddr[6];
32	struct in_addr addr;
33	int number;
34	} BOOTPClient;
35	/** Number of DHCP clients supported by NAT. */
36	#define NB_ADDR 16
37
38	#define bootp_clients ((BOOTPClient *)pData->pbootp_clients)
39
40	/* XXX: only DHCP is supported */
41	static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
42
43	static void bootp_reply(PNATState pData, struct mbuf *m0, int offReply, uint16_t flags);
44
45	static uint8_t dhcp_find_option(uint8_t vend, uint8_t tag)
46	{
47	uint8_t *q = vend;
48	uint8_t len;
49	/@todo magic validation /
50	q += 4; /magic/
51	while(*q != RFC1533_END)
52	{
53	if (*q == RFC1533_PAD)
54	continue;
55	if (*q == tag)
56	return q;
57	q++;
58	len = *q;
59	q += 1 + len;
60	}
61	return NULL;
62	}
63
64	static BOOTPClient *bc_alloc_client(PNATState pData)
65	{
66	int i;
67	for (i = 0; i < NB_ADDR; i++)
68	{
69	if (!bootp_clients[i].allocated)
70	{
71	BOOTPClient *bc;
72
73	bc = &bootp_clients[i];
74	memset(bc, 0, sizeof(BOOTPClient));
75	bc->allocated = 1;
76	bc->number = i;
77	return bc;
78	}
79	}
80	return NULL;
81	}
82
83	static BOOTPClient get_new_addr(PNATState pData, struct in_addr paddr)
84	{
85	BOOTPClient *bc;
86	bc = bc_alloc_client(pData);
87	if (!bc)
88	return NULL;
89
90	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (bc->number + START_ADDR));
91	bc->addr.s_addr = paddr->s_addr;
92	return bc;
93	}
94
95	static int release_addr(PNATState pData, struct in_addr *paddr)
96	{
97	unsigned i;
98	for (i = 0; i < NB_ADDR; i++)
99	{
100	if (paddr->s_addr == bootp_clients[i].addr.s_addr)
101	{
102	memset(&bootp_clients[i], 0, sizeof(BOOTPClient));
103	return VINF_SUCCESS;
104	}
105	}
106	return VERR_NOT_FOUND;
107	}
108
109	/*
110	* from RFC 2131 4.3.1
111	* Field DHCPOFFER DHCPACK DHCPNAK
112	* ----- --------- ------- -------
113	* 'op' BOOTREPLY BOOTREPLY BOOTREPLY
114	* 'htype' (From "Assigned Numbers" RFC)
115	* 'hlen' (Hardware address length in octets)
116	* 'hops' 0 0 0
117	* 'xid' 'xid' from client 'xid' from client 'xid' from client
118	* DHCPDISCOVER DHCPREQUEST DHCPREQUEST
119	* message message message
120	* 'secs' 0 0 0
121	* 'ciaddr' 0 'ciaddr' from 0
122	* DHCPREQUEST or 0
123	* 'yiaddr' IP address offered IP address 0
124	* to client assigned to client
125	* 'siaddr' IP address of next IP address of next 0
126	* bootstrap server bootstrap server
127	* 'flags' 'flags' from 'flags' from 'flags' from
128	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
129	* message message message
130	* 'giaddr' 'giaddr' from 'giaddr' from 'giaddr' from
131	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
132	* message message message
133	* 'chaddr' 'chaddr' from 'chaddr' from 'chaddr' from
134	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
135	* message message message
136	* 'sname' Server host name Server host name (unused)
137	* or options or options
138	* 'file' Client boot file Client boot file (unused)
139	* name or options name or options
140	* 'options' options options
141	*
142	* Option DHCPOFFER DHCPACK DHCPNAK
143	* ------ --------- ------- -------
144	* Requested IP address MUST NOT MUST NOT MUST NOT
145	* IP address lease time MUST MUST (DHCPREQUEST) MUST NOT
146	* MUST NOT (DHCPINFORM)
147	* Use 'file'/'sname' fields MAY MAY MUST NOT
148	* DHCP message type DHCPOFFER DHCPACK DHCPNAK
149	* Parameter request list MUST NOT MUST NOT MUST NOT
150	* Message SHOULD SHOULD SHOULD
151	* Client identifier MUST NOT MUST NOT MAY
152	* Vendor class identifier MAY MAY MAY
153	* Server identifier MUST MUST MUST
154	* Maximum message size MUST NOT MUST NOT MUST NOT
155	* All others MAY MAY MUST NOT
156	*/
157	static BOOTPClient find_addr(PNATState pData, struct in_addr paddr, const uint8_t *macaddr)
158	{
159	int i;
160
161	for (i = 0; i < NB_ADDR; i++)
162	{
163	if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
164	{
165	BOOTPClient *bc;
166
167	bc = &bootp_clients[i];
168	bc->allocated = 1;
169	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (i + START_ADDR));
170	return bc;
171	}
172	}
173	return NULL;
174	}
175
176	static struct mbuf dhcp_create_msg(PNATState pData, struct bootp_t bp, struct mbuf *m, uint8_t type)
177	{
178	struct bootp_t *rbp;
179	struct ethhdr *eh;
180	uint8_t *q;
181
182	eh = mtod(m, struct ethhdr *);
183	memcpy(eh->h_source, bp->bp_hwaddr, ETH_ALEN); /* XXX: if_encap just swap source with dest*/
184
185	m->m_data += if_maxlinkhdr; /reserve ether header /
186
187	rbp = mtod(m, struct bootp_t *);
188	memset(rbp, 0, sizeof(struct bootp_t));
189	rbp->bp_op = BOOTP_REPLY;
190	rbp->bp_xid = bp->bp_xid; /* see table 3 of rfc2131*/
191	rbp->bp_flags = bp->bp_flags; /* figure 2 of rfc2131 */
192	rbp->bp_giaddr.s_addr = bp->bp_giaddr.s_addr;
193	#if 0 /check flags/
194	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
195	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
196	#endif
197	rbp->bp_htype = 1;
198	rbp->bp_hlen = 6;
199	memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
200
201	memcpy(rbp->bp_vend, rfc1533_cookie, 4); /* cookie */
202	q = rbp->bp_vend;
203	q += 4;
204	*q++ = RFC2132_MSG_TYPE;
205	*q++ = 1;
206	*q++ = type;
207
208	return m;
209	}
210
211	static int dhcp_do_ack_offer(PNATState pData, struct mbuf m, BOOTPClient bc, int fDhcpRequest)
212	{
213	struct bootp_t *rbp = NULL;
214	uint8_t *q;
215	struct in_addr saddr;
216	int val;
217
218	struct dns_entry *de = NULL;
219	struct dns_domain_entry *dd = NULL;
220	int added = 0;
221	uint8_t *q_dns_header = NULL;
222	uint32_t lease_time = RT_H2N_U32_C(LEASE_TIME);
223	uint32_t netmask = RT_H2N_U32(pData->netmask);
224
225	rbp = mtod(m, struct bootp_t *);
226	q = &rbp->bp_vend[0];
227	q += 7; /* !cookie rfc 2132 + TYPE*/
228
229	/DHCP Offer specific/
230	if ( tftp_prefix
231	&& RTDirExists(tftp_prefix)
232	&& bootp_filename)
233	RTStrPrintf((char*)rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
234
235	Log(("NAT: DHCP: bp_file:%s\n", &rbp->bp_file));
236	/* Address/port of the DHCP server. */
237	rbp->bp_yiaddr = bc->addr; /* Client IP address */
238	Log(("NAT: DHCP: bp_yiaddr:%R[IP4]\n", &rbp->bp_yiaddr));
239	rbp->bp_siaddr = pData->tftp_server; /* Next Server IP address, i.e. TFTP */
240	Log(("NAT: DHCP: bp_siaddr:%R[IP4]\n", &rbp->bp_siaddr));
241	if (fDhcpRequest)
242	{
243	rbp->bp_ciaddr.s_addr = bc->addr.s_addr; /* Client IP address */
244	}
245	#ifndef VBOX_WITH_NAT_SERVICE
246	saddr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
247	#else
248	saddr.s_addr = pData->special_addr.s_addr;
249	#endif
250	Log(("NAT: DHCP: s_addr:%R[IP4]\n", &saddr));
251
252	#define FILL_BOOTP_EXT(q, tag, len, pvalue) \
253	do { \
254	struct bootp_ext be = (struct bootp_ext )(q); \
255	be->bpe_tag = (tag); \
256	be->bpe_len = (len); \
257	memcpy(&be[1], (pvalue), (len)); \
258	(q) = (uint8_t *)(&be[1]) + (len); \
259	}while(0)
260	/* appending another value to tag, calculates len of whole block*/
261	#define FILL_BOOTP_APP(head, q, tag, len, pvalue) \
262	do { \
263	struct bootp_ext be = (struct bootp_ext )(head); \
264	memcpy(q, (pvalue), (len)); \
265	(q) += (len); \
266	Assert(be->bpe_tag == (tag)); \
267	be->bpe_len += (len); \
268	}while(0)
269
270
271	FILL_BOOTP_EXT(q, RFC1533_NETMASK, 4, &netmask);
272	FILL_BOOTP_EXT(q, RFC1533_GATEWAY, 4, &saddr);
273
274	if (pData->use_dns_proxy \|\| pData->use_host_resolver)
275	{
276	uint32_t addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_DNS);
277	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &addr);
278	goto skip_dns_servers;
279	}
280
281	if (!TAILQ_EMPTY(&pData->pDnsList))
282	{
283	de = TAILQ_LAST(&pData->pDnsList, dns_list_head);
284	q_dns_header = q;
285	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &de->de_addr.s_addr);
286	}
287
288	TAILQ_FOREACH_REVERSE(de, &pData->pDnsList, dns_list_head, de_list)
289	{
290	if (TAILQ_LAST(&pData->pDnsList, dns_list_head) == de)
291	continue; /* first value with head we've ingected before */
292	FILL_BOOTP_APP(q_dns_header, q, RFC1533_DNS, 4, &de->de_addr.s_addr);
293	}
294
295	skip_dns_servers:
296	if (LIST_EMPTY(&pData->pDomainList))
297	{
298	/* Microsoft dhcp client doen't like domain-less dhcp and trimmed packets*/
299	/* dhcpcd client very sad if no domain name is passed */
300	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, " ");
301	}
302	if (pData->fPassDomain && !pData->use_host_resolver)
303	{
304	LIST_FOREACH(dd, &pData->pDomainList, dd_list)
305	{
306
307	if (dd->dd_pszDomain == NULL)
308	continue;
309	/* never meet valid separator here in RFC1533*/
310	if (added != 0)
311	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, ",");
312	else
313	added = 1;
314	val = (int)strlen(dd->dd_pszDomain);
315	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, dd->dd_pszDomain);
316	}
317	}
318
319	FILL_BOOTP_EXT(q, RFC2132_LEASE_TIME, 4, &lease_time);
320
321	if (*slirp_hostname)
322	{
323	val = (int)strlen(slirp_hostname);
324	FILL_BOOTP_EXT(q, RFC1533_HOSTNAME, val, slirp_hostname);
325	}
326	slirp_arp_cache_update_or_add(pData, rbp->bp_yiaddr.s_addr, bc->macaddr);
327	return q - rbp->bp_vend; /return offset /
328	}
329
330	static int dhcp_send_nack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
331	{
332	struct bootp_t *rbp;
333	uint8_t *q = NULL;
334	rbp = mtod(m, struct bootp_t *);
335
336	dhcp_create_msg(pData, bp, m, DHCPNAK);
337	return 7;
338	}
339
340	static int dhcp_send_ack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m, int fDhcpRequest)
341	{
342	struct bootp_t *rbp;
343	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
344
345	dhcp_create_msg(pData, bp, m, DHCPACK);
346	offReply = dhcp_do_ack_offer(pData, m, bc, fDhcpRequest);
347	return offReply;
348	}
349
350	static int dhcp_send_offer(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
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, DHCPOFFER);
355	offReply = dhcp_do_ack_offer(pData, m, bc, /* fDhcpRequest=*/ 0);
356	return offReply;
357	}
358
359	/**
360	* decoding client messages RFC2131 (4.3.6)
361	* ---------------------------------------------------------------------
362	* \| \|INIT-REBOOT \|SELECTING \|RENEWING \|REBINDING \|
363	* ---------------------------------------------------------------------
364	* \|broad/unicast \|broadcast \|broadcast \|unicast \|broadcast \|
365	* \|server-ip \|MUST NOT \|MUST \|MUST NOT \|MUST NOT \|
366	* \|requested-ip \|MUST \|MUST \|MUST NOT \|MUST NOT \|
367	* \|ciaddr \|zero \|zero \|IP address \|IP address\|
368	* ---------------------------------------------------------------------
369	*
370	*/
371
372	enum DHCP_REQUEST_STATES
373	{
374	INIT_REBOOT,
375	SELECTING,
376	RENEWING,
377	REBINDING,
378	NONE
379	};
380
381	static int dhcp_decode_request(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, struct mbuf *m)
382	{
383	BOOTPClient *bc = NULL;
384	struct in_addr daddr;
385	int offReply;
386	uint8_t *opt;
387	uint8_t *req_ip = NULL;
388	uint8_t *server_ip = NULL;
389	uint32_t ui32;
390	enum DHCP_REQUEST_STATES dhcp_stat = NONE;
391
392	/* need to understand which type of request we get */
393	req_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
394	server_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_SRV_ID);
395	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
396
397	if (server_ip != NULL)
398	{
399	/* selecting */
400	if (!bc)
401	{
402	LogRel(("NAT: DHCP no IP was allocated\n"));
403	return -1;
404	}
405
406	dhcp_stat = SELECTING;
407	Assert((bp->bp_ciaddr.s_addr == INADDR_ANY));
408	Assert(((uint32_t )(req_ip + 2) == bc->addr.s_addr)); /the same address as in offer/
409	#if 0
410	/* DSL xid in request differ from offer */
411	Assert((bp->bp_xid == bc->xid));
412	#endif
413	}
414	else
415	{
416	if (req_ip != NULL)
417	{
418	/* init-reboot */
419	dhcp_stat = INIT_REBOOT;
420	}
421	else
422	{
423	/* table 4 of rfc2131 */
424	if (bp->bp_flags & RT_H2N_U16_C(DHCP_FLAGS_B))
425	dhcp_stat = REBINDING;
426	else
427	dhcp_stat = RENEWING;
428	}
429	}
430
431	/?? renewing ??/
432	switch (dhcp_stat)
433	{
434	case RENEWING:
435	Assert((server_ip == NULL && req_ip == NULL && bp->bp_ciaddr.s_addr != INADDR_ANY));
436	if (bc != NULL)
437	{
438	Assert((bc->addr.s_addr == bp->bp_ciaddr.s_addr));
439	/if it already here well just do ack, we aren't aware of dhcp time expiration/
440	}
441	else
442	{
443	if ((bp->bp_ciaddr.s_addr & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
444	{
445	LogRel(("NAT: Client %R[IP4] requested IP -- sending NAK\n", &bp->bp_ciaddr));
446	offReply = dhcp_send_nack(pData, bp, bc, m);
447	return offReply;
448	}
449
450	bc = bc_alloc_client(pData);
451	if (!bc)
452	{
453	LogRel(("NAT: can't alloc address. RENEW has been silently ignored.\n"));
454	return -1;
455	}
456
457	Assert((bp->bp_hlen == ETH_ALEN));
458	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
459	bc->addr.s_addr = bp->bp_ciaddr.s_addr;
460	}
461	break;
462
463	case INIT_REBOOT:
464	Assert(server_ip == NULL);
465	Assert(req_ip != NULL);
466	ui32 = (uint32_t )(req_ip + 2);
467	if ((ui32 & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
468	{
469	LogRel(("NAT: address %R[IP4] has been requested -- sending NAK\n", &ui32));
470	offReply = dhcp_send_nack(pData, bp, bc, m);
471	return offReply;
472	}
473
474	bc = bc_alloc_client(pData);
475	if (!bc)
476	{
477	LogRel(("NAT: can't alloc address. RENEW has been silently ignored\n"));
478	return -1;
479	}
480	Assert((bp->bp_hlen == ETH_ALEN));
481	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
482	bc->addr.s_addr = ui32;
483	break;
484
485	case NONE:
486	Assert((dhcp_stat != NONE));
487	return -1;
488
489	default:
490	break;
491	}
492
493	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
494	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 1);
495	return offReply;
496	}
497
498	static int dhcp_decode_discover(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, int fDhcpDiscover, struct mbuf *m)
499	{
500	BOOTPClient *bc;
501	struct in_addr daddr;
502	int offReply;
503
504	if (fDhcpDiscover)
505	{
506	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
507	if (!bc)
508	{
509	bc = get_new_addr(pData, &daddr);
510	if (!bc)
511	{
512	LogRel(("NAT: DHCP no IP address left\n"));
513	Log(("no address left\n"));
514	return -1;
515	}
516	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
517	}
518
519	bc->xid = bp->bp_xid;
520	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
521	offReply = dhcp_send_offer(pData, bp, bc, m);
522	return offReply;
523	}
524	else
525	{
526	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
527	if (!bc)
528	{
529	LogRel(("NAT: DHCP Inform was ignored no boot client was found\n"));
530	return -1;
531	}
532
533	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
534	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 0);
535	return offReply;
536	}
537
538	return -1;
539	}
540
541	static int dhcp_decode_release(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
542	{
543	int rc = release_addr(pData, &bp->bp_ciaddr);
544	LogRel(("NAT: %s %R[IP4]\n",
545	RT_SUCCESS(rc) ? "DHCP released IP address" : "Ignored DHCP release for IP address",
546	&bp->bp_ciaddr));
547	return 0;
548	}
549	/**
550	* fields for discovering t
551	* Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE,
552	* DHCPINFORM DHCPRELEASE
553	* ----- ------------ ----------- -----------
554	* 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST
555	* 'htype' (From "Assigned Numbers" RFC)
556	* 'hlen' (Hardware address length in octets)
557	* 'hops' 0 0 0
558	* 'xid' selected by client 'xid' from server selected by
559	* DHCPOFFER message client
560	* 'secs' 0 or seconds since 0 or seconds since 0
561	* DHCP process started DHCP process started
562	* 'flags' Set 'BROADCAST' Set 'BROADCAST' 0
563	* flag if client flag if client
564	* requires broadcast requires broadcast
565	* reply reply
566	* 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE)
567	* client's network address client's network
568	* network address (BOUND/RENEW/REBIND) address
569	* (DHCPINFORM) (DHCPRELEASE)
570	* 'yiaddr' 0 0 0
571	* 'siaddr' 0 0 0
572	* 'giaddr' 0 0 0
573	* 'chaddr' client's hardware client's hardware client's hardware
574	* address address address
575	* 'sname' options, if options, if (unused)
576	* indicated in indicated in
577	* 'sname/file' 'sname/file'
578	* option; otherwise option; otherwise
579	* unused unused
580	* 'file' options, if options, if (unused)
581	* indicated in indicated in
582	* 'sname/file' 'sname/file'
583	* option; otherwise option; otherwise
584	* unused unused
585	* 'options' options options (unused)
586	* Requested IP address MAY MUST (in MUST
587	* (DISCOVER) SELECTING or (DHCPDECLINE),
588	* MUST NOT INIT-REBOOT) MUST NOT
589	* (INFORM) MUST NOT (in (DHCPRELEASE)
590	* BOUND or
591	* RENEWING)
592	* IP address lease time MAY MAY MUST NOT
593	* (DISCOVER)
594	* MUST NOT
595	* (INFORM)
596	* Use 'file'/'sname' fields MAY MAY MAY
597	* DHCP message type DHCPDISCOVER/ DHCPREQUEST DHCPDECLINE/
598	* DHCPINFORM DHCPRELEASE
599	* Client identifier MAY MAY MAY
600	* Vendor class identifier MAY MAY MUST NOT
601	* Server identifier MUST NOT MUST (after MUST
602	* SELECTING)
603	* MUST NOT (after
604	* INIT-REBOOT,
605	* BOUND, RENEWING
606	* or REBINDING)
607	* Parameter request list MAY MAY MUST NOT
608	* Maximum message size MAY MAY MUST NOT
609	* Message SHOULD NOT SHOULD NOT SHOULD
610	* Site-specific MAY MAY MUST NOT
611	* All others MAY MAY MUST NOT
612	*
613	*/
614	static void dhcp_decode(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
615	{
616	const uint8_t p, p_end;
617	int rc;
618	int pmsg_type;
619	struct in_addr req_ip;
620	int fDhcpDiscover = 0;
621	int len, tag;
622	struct mbuf *m = NULL;
623
624	pmsg_type = 0;
625	p = buf;
626	p_end = buf + size;
627	if (size < 5)
628	return;
629
630	if (memcmp(p, rfc1533_cookie, 4) != 0)
631	return;
632
633	p = dhcp_find_option(bp->bp_vend, RFC2132_MSG_TYPE);
634	Assert(p);
635	if (p == NULL)
636	return;
637
638	#ifndef VBOX_WITH_SLIRP_BSD_MBUF
639	if ((m = m_get(pData)) == NULL)
640	#else
641	if ((m = m_getcl(pData, M_DONTWAIT, MT_HEADER, M_PKTHDR)) == NULL)
642	#endif
643	{
644	LogRel(("NAT: can't alocate memory for response!\n"));
645	return;
646	}
647
648	switch (*(p+2))
649	{
650	case DHCPDISCOVER:
651	fDhcpDiscover = 1;
652	/**/
653	case DHCPINFORM:
654	rc = dhcp_decode_discover(pData, bp, buf, size, fDhcpDiscover, m);
655	if (rc > 0)
656	goto reply;
657	break;
658
659	case DHCPREQUEST:
660	rc = dhcp_decode_request(pData, bp, buf, size, m);
661	if (rc > 0)
662	goto reply;
663	break;
664
665	case DHCPRELEASE:
666	rc = dhcp_decode_release(pData, bp, buf, size);
667	/* no reply required */
668	break;
669
670	case DHCPDECLINE:
671	p = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
672	req_ip.s_addr = (uint32_t )(p + 2);
673	rc = bootp_cache_lookup_ether_by_ip(pData, req_ip.s_addr, NULL);
674	if (RT_FAILURE(rc))
675	{
676	/* Not registered */
677	BOOTPClient *bc;
678	bc = bc_alloc_client(pData);
679	Assert(bc);
680	bc->addr.s_addr = req_ip.s_addr;
681	slirp_arp_who_has(pData, bc->addr.s_addr);
682	LogRel(("NAT: %R[IP4] has been already registered\n", &req_ip));
683	}
684	/* no response required */
685	break;
686
687	default:
688	AssertMsgFailed(("unsupported DHCP message type"));
689	}
690	Assert(m);
691	/silently ignore/
692	m_free(pData, m);
693	return;
694
695	reply:
696	bootp_reply(pData, m, rc, bp->bp_flags);
697	return;
698	}
699
700	static void bootp_reply(PNATState pData, struct mbuf *m, int offReply, uint16_t flags)
701	{
702	struct sockaddr_in saddr, daddr;
703	struct bootp_t *rbp = NULL;
704	uint8_t *q = NULL;
705	int nack;
706	rbp = mtod(m, struct bootp_t *);
707	Assert((m));
708	Assert((rbp));
709	q = rbp->bp_vend;
710	nack = (q[6] == DHCPNAK);
711	q += offReply;
712
713	#ifndef VBOX_WITH_NAT_SERVICE
714	saddr.sin_addr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
715	#else
716	saddr.sin_addr.s_addr = pData->special_addr.s_addr;
717	#endif
718
719	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
720
721	q++ = RFC1533_END; / end of message */
722
723	#ifdef VBOX_WITH_SLIRP_BSD_MBUF
724	m->m_pkthdr.header = mtod(m, void *);
725	#endif
726	m->m_len = sizeof(struct bootp_t)
727	- sizeof(struct ip)
728	- sizeof(struct udphdr);
729	m->m_data += sizeof(struct udphdr)
730	+ sizeof(struct ip);
731	if ( (flags & RT_H2N_U16_C(DHCP_FLAGS_B))
732	\|\| nack != 0)
733	daddr.sin_addr.s_addr = INADDR_BROADCAST;
734	else
735	daddr.sin_addr.s_addr = rbp->bp_yiaddr.s_addr; /unicast requested by client/
736	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
737	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
738	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
739	}
740
741	void bootp_input(PNATState pData, struct mbuf *m)
742	{
743	struct bootp_t bp = mtod(m, struct bootp_t );
744
745	if (bp->bp_op == BOOTP_REQUEST)
746	dhcp_decode(pData, bp, bp->bp_vend, DHCP_OPT_LEN);
747	}
748
749	int bootp_cache_lookup_ip_by_ether(PNATState pData,const uint8_t* ether, uint32_t *pip)
750	{
751	int i;
752
753	if (!ether \|\| !pip)
754	return VERR_INVALID_PARAMETER;
755
756	for (i = 0; i < NB_ADDR; i++)
757	{
758	if ( bootp_clients[i].allocated
759	&& memcmp(bootp_clients[i].macaddr, ether, ETH_ALEN) == 0)
760	{
761	*pip = bootp_clients[i].addr.s_addr;
762	return VINF_SUCCESS;
763	}
764	}
765
766	*pip = INADDR_ANY;
767	return VERR_NOT_FOUND;
768	}
769
770	int bootp_cache_lookup_ether_by_ip(PNATState pData, uint32_t ip, uint8_t *ether)
771	{
772	int i;
773	for (i = 0; i < NB_ADDR; i++)
774	{
775	if ( bootp_clients[i].allocated
776	&& ip == bootp_clients[i].addr.s_addr)
777	{
778	if (ether != NULL)
779	memcpy(ether, bootp_clients[i].macaddr, ETH_ALEN);
780	return VINF_SUCCESS;
781	}
782	}
783
784	return VERR_NOT_FOUND;
785	}
786
787	/*
788	* Initialize dhcp server
789	* @returns 0 - if initialization is ok, non-zero otherwise
790	*/
791	int bootp_dhcp_init(PNATState pData)
792	{
793	pData->pbootp_clients = RTMemAllocZ(sizeof(BOOTPClient) * NB_ADDR);
794	if (!pData->pbootp_clients)
795	return VERR_NO_MEMORY;
796
797	return VINF_SUCCESS;
798	}
799
800	int bootp_dhcp_fini(PNATState pData)
801	{
802	if (pData->pbootp_clients != NULL)
803	RTMemFree(pData->pbootp_clients);
804
805	return VINF_SUCCESS;
806	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 26817

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