bootp.c@ 27797

最後變更在這個檔案從27797是 27797,由 vboxsync 提交於 15 年前
misc compiler warning fixes, comment typos and other minor cleanups
屬性 svn:eol-style 設為 `native`
檔案大小: 26.9 KB

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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	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
343
344	dhcp_create_msg(pData, bp, m, DHCPACK);
345	offReply = dhcp_do_ack_offer(pData, m, bc, fDhcpRequest);
346	return offReply;
347	}
348
349	static int dhcp_send_offer(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
350	{
351	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
352
353	dhcp_create_msg(pData, bp, m, DHCPOFFER);
354	offReply = dhcp_do_ack_offer(pData, m, bc, /* fDhcpRequest=*/ 0);
355	return offReply;
356	}
357
358	/**
359	* decoding client messages RFC2131 (4.3.6)
360	* ---------------------------------------------------------------------
361	* \| \|INIT-REBOOT \|SELECTING \|RENEWING \|REBINDING \|
362	* ---------------------------------------------------------------------
363	* \|broad/unicast \|broadcast \|broadcast \|unicast \|broadcast \|
364	* \|server-ip \|MUST NOT \|MUST \|MUST NOT \|MUST NOT \|
365	* \|requested-ip \|MUST \|MUST \|MUST NOT \|MUST NOT \|
366	* \|ciaddr \|zero \|zero \|IP address \|IP address\|
367	* ---------------------------------------------------------------------
368	*
369	*/
370
371	enum DHCP_REQUEST_STATES
372	{
373	INIT_REBOOT,
374	SELECTING,
375	RENEWING,
376	REBINDING,
377	NONE
378	};
379
380	static int dhcp_decode_request(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, struct mbuf *m)
381	{
382	BOOTPClient *bc = NULL;
383	struct in_addr daddr;
384	int offReply;
385	uint8_t *req_ip = NULL;
386	uint8_t *server_ip = NULL;
387	uint32_t ui32;
388	enum DHCP_REQUEST_STATES dhcp_stat = NONE;
389
390	/* need to understand which type of request we get */
391	req_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
392	server_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_SRV_ID);
393	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
394
395	if (server_ip != NULL)
396	{
397	/* selecting */
398	if (!bc)
399	{
400	LogRel(("NAT: DHCP no IP was allocated\n"));
401	return -1;
402	}
403
404	dhcp_stat = SELECTING;
405	Assert((bp->bp_ciaddr.s_addr == INADDR_ANY));
406	Assert(((uint32_t )(req_ip + 2) == bc->addr.s_addr)); /the same address as in offer/
407	#if 0
408	/* DSL xid in request differ from offer */
409	Assert((bp->bp_xid == bc->xid));
410	#endif
411	}
412	else
413	{
414	if (req_ip != NULL)
415	{
416	/* init-reboot */
417	dhcp_stat = INIT_REBOOT;
418	}
419	else
420	{
421	/* table 4 of rfc2131 */
422	if (bp->bp_flags & RT_H2N_U16_C(DHCP_FLAGS_B))
423	dhcp_stat = REBINDING;
424	else
425	dhcp_stat = RENEWING;
426	}
427	}
428
429	/?? renewing ??/
430	switch (dhcp_stat)
431	{
432	case RENEWING:
433	Assert((server_ip == NULL && req_ip == NULL && bp->bp_ciaddr.s_addr != INADDR_ANY));
434	if (bc != NULL)
435	{
436	Assert((bc->addr.s_addr == bp->bp_ciaddr.s_addr));
437	/if it already here well just do ack, we aren't aware of dhcp time expiration/
438	}
439	else
440	{
441	if ((bp->bp_ciaddr.s_addr & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
442	{
443	LogRel(("NAT: Client %R[IP4] requested IP -- sending NAK\n", &bp->bp_ciaddr));
444	offReply = dhcp_send_nack(pData, bp, bc, m);
445	return offReply;
446	}
447
448	bc = bc_alloc_client(pData);
449	if (!bc)
450	{
451	LogRel(("NAT: can't alloc address. RENEW has been silently ignored.\n"));
452	return -1;
453	}
454
455	Assert((bp->bp_hlen == ETH_ALEN));
456	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
457	bc->addr.s_addr = bp->bp_ciaddr.s_addr;
458	}
459	break;
460
461	case INIT_REBOOT:
462	Assert(server_ip == NULL);
463	Assert(req_ip != NULL);
464	ui32 = (uint32_t )(req_ip + 2);
465	if ((ui32 & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
466	{
467	LogRel(("NAT: address %R[IP4] has been requested -- sending NAK\n", &ui32));
468	offReply = dhcp_send_nack(pData, bp, bc, m);
469	return offReply;
470	}
471
472	bc = bc_alloc_client(pData);
473	if (!bc)
474	{
475	LogRel(("NAT: can't alloc address. RENEW has been silently ignored\n"));
476	return -1;
477	}
478	Assert((bp->bp_hlen == ETH_ALEN));
479	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
480	bc->addr.s_addr = ui32;
481	break;
482
483	case NONE:
484	Assert((dhcp_stat != NONE));
485	return -1;
486
487	default:
488	break;
489	}
490
491	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
492	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 1);
493	return offReply;
494	}
495
496	static int dhcp_decode_discover(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, int fDhcpDiscover, struct mbuf *m)
497	{
498	BOOTPClient *bc;
499	struct in_addr daddr;
500	int offReply;
501
502	if (fDhcpDiscover)
503	{
504	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
505	if (!bc)
506	{
507	bc = get_new_addr(pData, &daddr);
508	if (!bc)
509	{
510	LogRel(("NAT: DHCP no IP address left\n"));
511	Log(("no address left\n"));
512	return -1;
513	}
514	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
515	}
516
517	bc->xid = bp->bp_xid;
518	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
519	offReply = dhcp_send_offer(pData, bp, bc, m);
520	return offReply;
521	}
522	else
523	{
524	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
525	if (!bc)
526	{
527	LogRel(("NAT: DHCP Inform was ignored no boot client was found\n"));
528	return -1;
529	}
530
531	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
532	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 0);
533	return offReply;
534	}
535
536	return -1;
537	}
538
539	static int dhcp_decode_release(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
540	{
541	int rc = release_addr(pData, &bp->bp_ciaddr);
542	LogRel(("NAT: %s %R[IP4]\n",
543	RT_SUCCESS(rc) ? "DHCP released IP address" : "Ignored DHCP release for IP address",
544	&bp->bp_ciaddr));
545	return 0;
546	}
547	/**
548	* fields for discovering t
549	* Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE,
550	* DHCPINFORM DHCPRELEASE
551	* ----- ------------ ----------- -----------
552	* 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST
553	* 'htype' (From "Assigned Numbers" RFC)
554	* 'hlen' (Hardware address length in octets)
555	* 'hops' 0 0 0
556	* 'xid' selected by client 'xid' from server selected by
557	* DHCPOFFER message client
558	* 'secs' 0 or seconds since 0 or seconds since 0
559	* DHCP process started DHCP process started
560	* 'flags' Set 'BROADCAST' Set 'BROADCAST' 0
561	* flag if client flag if client
562	* requires broadcast requires broadcast
563	* reply reply
564	* 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE)
565	* client's network address client's network
566	* network address (BOUND/RENEW/REBIND) address
567	* (DHCPINFORM) (DHCPRELEASE)
568	* 'yiaddr' 0 0 0
569	* 'siaddr' 0 0 0
570	* 'giaddr' 0 0 0
571	* 'chaddr' client's hardware client's hardware client's hardware
572	* address address address
573	* 'sname' options, if options, if (unused)
574	* indicated in indicated in
575	* 'sname/file' 'sname/file'
576	* option; otherwise option; otherwise
577	* unused unused
578	* 'file' options, if options, if (unused)
579	* indicated in indicated in
580	* 'sname/file' 'sname/file'
581	* option; otherwise option; otherwise
582	* unused unused
583	* 'options' options options (unused)
584	* Requested IP address MAY MUST (in MUST
585	* (DISCOVER) SELECTING or (DHCPDECLINE),
586	* MUST NOT INIT-REBOOT) MUST NOT
587	* (INFORM) MUST NOT (in (DHCPRELEASE)
588	* BOUND or
589	* RENEWING)
590	* IP address lease time MAY MAY MUST NOT
591	* (DISCOVER)
592	* MUST NOT
593	* (INFORM)
594	* Use 'file'/'sname' fields MAY MAY MAY
595	* DHCP message type DHCPDISCOVER/ DHCPREQUEST DHCPDECLINE/
596	* DHCPINFORM DHCPRELEASE
597	* Client identifier MAY MAY MAY
598	* Vendor class identifier MAY MAY MUST NOT
599	* Server identifier MUST NOT MUST (after MUST
600	* SELECTING)
601	* MUST NOT (after
602	* INIT-REBOOT,
603	* BOUND, RENEWING
604	* or REBINDING)
605	* Parameter request list MAY MAY MUST NOT
606	* Maximum message size MAY MAY MUST NOT
607	* Message SHOULD NOT SHOULD NOT SHOULD
608	* Site-specific MAY MAY MUST NOT
609	* All others MAY MAY MUST NOT
610	*
611	*/
612	static void dhcp_decode(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
613	{
614	const uint8_t p, p_end;
615	int rc;
616	int pmsg_type;
617	struct in_addr req_ip;
618	int fDhcpDiscover = 0;
619	struct mbuf *m = NULL;
620
621	pmsg_type = 0;
622	p = buf;
623	p_end = buf + size;
624	if (size < 5)
625	return;
626
627	if (memcmp(p, rfc1533_cookie, 4) != 0)
628	return;
629
630	p = dhcp_find_option(bp->bp_vend, RFC2132_MSG_TYPE);
631	Assert(p);
632	if (p == NULL)
633	return;
634
635	#ifndef VBOX_WITH_SLIRP_BSD_MBUF
636	if ((m = m_get(pData)) == NULL)
637	#else
638	if ((m = m_getcl(pData, M_DONTWAIT, MT_HEADER, M_PKTHDR)) == NULL)
639	#endif
640	{
641	LogRel(("NAT: can't alocate memory for response!\n"));
642	return;
643	}
644
645	switch (*(p+2))
646	{
647	case DHCPDISCOVER:
648	fDhcpDiscover = 1;
649	/**/
650	case DHCPINFORM:
651	rc = dhcp_decode_discover(pData, bp, buf, size, fDhcpDiscover, m);
652	if (rc > 0)
653	goto reply;
654	break;
655
656	case DHCPREQUEST:
657	rc = dhcp_decode_request(pData, bp, buf, size, m);
658	if (rc > 0)
659	goto reply;
660	break;
661
662	case DHCPRELEASE:
663	rc = dhcp_decode_release(pData, bp, buf, size);
664	/* no reply required */
665	break;
666
667	case DHCPDECLINE:
668	p = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
669	req_ip.s_addr = (uint32_t )(p + 2);
670	rc = bootp_cache_lookup_ether_by_ip(pData, req_ip.s_addr, NULL);
671	if (RT_FAILURE(rc))
672	{
673	/* Not registered */
674	BOOTPClient *bc;
675	bc = bc_alloc_client(pData);
676	Assert(bc);
677	bc->addr.s_addr = req_ip.s_addr;
678	slirp_arp_who_has(pData, bc->addr.s_addr);
679	LogRel(("NAT: %R[IP4] has been already registered\n", &req_ip));
680	}
681	/* no response required */
682	break;
683
684	default:
685	AssertMsgFailed(("unsupported DHCP message type"));
686	}
687	Assert(m);
688	/silently ignore/
689	m_free(pData, m);
690	return;
691
692	reply:
693	bootp_reply(pData, m, rc, bp->bp_flags);
694	return;
695	}
696
697	static void bootp_reply(PNATState pData, struct mbuf *m, int offReply, uint16_t flags)
698	{
699	struct sockaddr_in saddr, daddr;
700	struct bootp_t *rbp = NULL;
701	uint8_t *q = NULL;
702	int nack;
703	rbp = mtod(m, struct bootp_t *);
704	Assert((m));
705	Assert((rbp));
706	q = rbp->bp_vend;
707	nack = (q[6] == DHCPNAK);
708	q += offReply;
709
710	#ifndef VBOX_WITH_NAT_SERVICE
711	saddr.sin_addr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
712	#else
713	saddr.sin_addr.s_addr = pData->special_addr.s_addr;
714	#endif
715
716	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
717
718	q++ = RFC1533_END; / end of message */
719
720	#ifdef VBOX_WITH_SLIRP_BSD_MBUF
721	m->m_pkthdr.header = mtod(m, void *);
722	#endif
723	m->m_len = sizeof(struct bootp_t)
724	- sizeof(struct ip)
725	- sizeof(struct udphdr);
726	m->m_data += sizeof(struct udphdr)
727	+ sizeof(struct ip);
728	if ( (flags & RT_H2N_U16_C(DHCP_FLAGS_B))
729	\|\| nack != 0)
730	daddr.sin_addr.s_addr = INADDR_BROADCAST;
731	else
732	daddr.sin_addr.s_addr = rbp->bp_yiaddr.s_addr; /unicast requested by client/
733	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
734	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
735	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
736	}
737
738	void bootp_input(PNATState pData, struct mbuf *m)
739	{
740	struct bootp_t bp = mtod(m, struct bootp_t );
741
742	if (bp->bp_op == BOOTP_REQUEST)
743	dhcp_decode(pData, bp, bp->bp_vend, DHCP_OPT_LEN);
744	}
745
746	int bootp_cache_lookup_ip_by_ether(PNATState pData,const uint8_t* ether, uint32_t *pip)
747	{
748	int i;
749
750	if (!ether \|\| !pip)
751	return VERR_INVALID_PARAMETER;
752
753	for (i = 0; i < NB_ADDR; i++)
754	{
755	if ( bootp_clients[i].allocated
756	&& memcmp(bootp_clients[i].macaddr, ether, ETH_ALEN) == 0)
757	{
758	*pip = bootp_clients[i].addr.s_addr;
759	return VINF_SUCCESS;
760	}
761	}
762
763	*pip = INADDR_ANY;
764	return VERR_NOT_FOUND;
765	}
766
767	int bootp_cache_lookup_ether_by_ip(PNATState pData, uint32_t ip, uint8_t *ether)
768	{
769	int i;
770	for (i = 0; i < NB_ADDR; i++)
771	{
772	if ( bootp_clients[i].allocated
773	&& ip == bootp_clients[i].addr.s_addr)
774	{
775	if (ether != NULL)
776	memcpy(ether, bootp_clients[i].macaddr, ETH_ALEN);
777	return VINF_SUCCESS;
778	}
779	}
780
781	return VERR_NOT_FOUND;
782	}
783
784	/*
785	* Initialize dhcp server
786	* @returns 0 - if initialization is ok, non-zero otherwise
787	*/
788	int bootp_dhcp_init(PNATState pData)
789	{
790	pData->pbootp_clients = RTMemAllocZ(sizeof(BOOTPClient) * NB_ADDR);
791	if (!pData->pbootp_clients)
792	return VERR_NO_MEMORY;
793
794	return VINF_SUCCESS;
795	}
796
797	int bootp_dhcp_fini(PNATState pData)
798	{
799	if (pData->pbootp_clients != NULL)
800	RTMemFree(pData->pbootp_clients);
801
802	return VINF_SUCCESS;
803	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 27797

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