ipv4.cpp@ 24873

Last change on this file since 24873 was 21337, checked in by vboxsync, 16 years ago
IPRT,HostDrv,AddDrv: Export public IPRT symbols for the linux kernel (pain).
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1	/* $Id: ipv4.cpp 21337 2009-07-07 14:58:27Z vboxsync $ */
2	/** @file
3	* IPRT - IPv4 Checksum calculation and validation.
4	*/
5
6	/*
7	* Copyright (C) 2008 Sun Microsystems, Inc.
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	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*
26	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31
32	/*******************************************************************************
33	* Header Files *
34	*******************************************************************************/
35	#include <iprt/net.h>
36	#include "internal/iprt.h"
37
38	#include <iprt/asm.h>
39	#include <iprt/assert.h>
40
41
42	/**
43	* Calculates the checksum of the IPv4 header.
44	*
45	* @returns Checksum (network endian).
46	* @param pIpHdr Pointer to the IPv4 header to checksum, network endian (big).
47	* Assumes the caller already checked the minimum size requirement.
48	*/
49	RTDECL(uint16_t) RTNetIPv4HdrChecksum(PCRTNETIPV4 pIpHdr)
50	{
51	uint16_t const paw = (uint16_t const )pIpHdr;
52	uint32_t u32Sum = paw[0] /* ip_hl */
53	+ paw[1] /* ip_len */
54	+ paw[2] /* ip_id */
55	+ paw[3] /* ip_off */
56	+ paw[4] /* ip_ttl */
57	/+ paw[5] == 0 / /* ip_sum */
58	+ paw[6] /* ip_src */
59	+ paw[7] /* ip_src:16 */
60	+ paw[8] /* ip_dst */
61	+ paw[9]; /* ip_dst:16 */
62	/* any options */
63	if (pIpHdr->ip_hl > 20 / 4)
64	{
65	/* this is a bit insane... (identical to the TCP header) */
66	switch (pIpHdr->ip_hl)
67	{
68	case 6: u32Sum += paw[10] + paw[11]; break;
69	case 7: u32Sum += paw[10] + paw[11] + paw[12] + paw[13]; break;
70	case 8: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15]; break;
71	case 9: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break;
72	case 10: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break;
73	case 11: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21]; break;
74	case 12: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23]; break;
75	case 13: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25]; break;
76	case 14: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27]; break;
77	case 15: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27] + paw[28] + paw[29]; break;
78	default:
79	AssertFailed();
80	}
81	}
82
83	/* 16-bit one complement fun */
84	u32Sum = (u32Sum >> 16) + (u32Sum & 0xffff); /* hi + low words */
85	u32Sum += u32Sum >> 16; /* carry */
86	return (uint16_t)~u32Sum;
87	}
88	RT_EXPORT_SYMBOL(RTNetIPv4HdrChecksum);
89
90
91	/**
92	* Verifies the header version, header size, packet size, and header checksum
93	* of the specified IPv4 header.
94	*
95	* @returns true if valid, false if invalid.
96	* @param pIpHdr Pointer to the IPv4 header to validate. Network endian (big).
97	* @param cbHdrMax The max header size, or the max size of what pIpHdr points
98	* to if you like. Note that an IPv4 header can be up to 60 bytes.
99	* @param cbPktMax The max IP packet size, IP header and payload. This doesn't have
100	* to be mapped following pIpHdr.
101	*/
102	RTDECL(bool) RTNetIPv4IsHdrValid(PCRTNETIPV4 pIpHdr, size_t cbHdrMax, size_t cbPktMax)
103	{
104	/*
105	* The header fields.
106	*/
107	Assert(cbPktMax >= cbHdrMax);
108	if (RT_UNLIKELY(cbHdrMax < RTNETIPV4_MIN_LEN))
109	return false;
110	if (RT_UNLIKELY(pIpHdr->ip_hl * 4 < RTNETIPV4_MIN_LEN))
111	return false;
112	if (RT_UNLIKELY((size_t)pIpHdr->ip_hl * 4 > cbHdrMax))
113	{
114	Assert((size_t)pIpHdr->ip_hl * 4 > cbPktMax); /* You'll hit this if you mapped/copy too little of the header! */
115	return false;
116	}
117	if (RT_UNLIKELY(pIpHdr->ip_v != 4))
118	return false;
119	if (RT_UNLIKELY(RT_BE2H_U16(pIpHdr->ip_len) > cbPktMax))
120	return false;
121
122	/*
123	* The header checksum.
124	*/
125	uint16_t u16Sum = RTNetIPv4HdrChecksum(pIpHdr);
126	if (RT_UNLIKELY(pIpHdr->ip_sum != u16Sum))
127	return false;
128	return true;
129	}
130	RT_EXPORT_SYMBOL(RTNetIPv4IsHdrValid);
131
132
133	/**
134	* Calculates the checksum of a pseudo header given an IPv4 header [inlined].
135	*
136	* @returns 32-bit intermediary checksum value.
137	* @param pIpHdr The IP header (network endian (big)).
138	*/
139	DECLINLINE(uint32_t) rtNetIPv4PseudoChecksum(PCRTNETIPV4 pIpHdr)
140	{
141	uint16_t cbPayload = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4;
142	uint32_t u32Sum = pIpHdr->ip_src.au16[0]
143	+ pIpHdr->ip_src.au16[1]
144	+ pIpHdr->ip_dst.au16[0]
145	+ pIpHdr->ip_dst.au16[1]
146	#ifdef RT_BIG_ENDIAN
147	+ pIpHdr->ip_p
148	#else
149	+ ((uint32_t)pIpHdr->ip_p << 8)
150	#endif
151	+ RT_H2BE_U16(cbPayload);
152	return u32Sum;
153	}
154
155
156	/**
157	* Calculates the checksum of a pseudo header given an IPv4 header.
158	*
159	* @returns 32-bit intermediary checksum value.
160	* @param pIpHdr The IP header (network endian (big)).
161	*/
162	RTDECL(uint32_t) RTNetIPv4PseudoChecksum(PCRTNETIPV4 pIpHdr)
163	{
164	return rtNetIPv4PseudoChecksum(pIpHdr);
165	}
166	RT_EXPORT_SYMBOL(RTNetIPv4PseudoChecksum);
167
168
169	/**
170	* Calculates the checksum of a pseudo header given the individual components.
171	*
172	* @returns 32-bit intermediary checksum value.
173	* @param SrcAddr The source address in host endian.
174	* @param DstAddr The destination address in host endian.
175	* @param bProtocol The protocol number.
176	* @param cbPkt The packet size (host endian of course) (no IPv4 header).
177	*/
178	RTDECL(uint32_t) RTNetIPv4PseudoChecksumBits(RTNETADDRIPV4 SrcAddr, RTNETADDRIPV4 DstAddr, uint8_t bProtocol, uint16_t cbPkt)
179	{
180	uint32_t u32Sum = RT_H2BE_U16(SrcAddr.au16[0])
181	+ RT_H2BE_U16(SrcAddr.au16[1])
182	+ RT_H2BE_U16(DstAddr.au16[0])
183	+ RT_H2BE_U16(DstAddr.au16[1])
184	#ifdef RT_BIG_ENDIAN
185	+ bProtocol
186	#else
187	+ ((uint32_t)bProtocol << 8)
188	#endif
189	+ RT_H2BE_U16(cbPkt);
190	return u32Sum;
191	}
192	RT_EXPORT_SYMBOL(RTNetIPv4PseudoChecksumBits);
193
194
195	/**
196	* Adds the checksum of the UDP header to the intermediate checksum value [inlined].
197	*
198	* @returns 32-bit intermediary checksum value.
199	* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
200	* @param u32Sum The 32-bit intermediate checksum value.
201	*/
202	DECLINLINE(uint32_t) rtNetIPv4AddUDPChecksum(PCRTNETUDP pUdpHdr, uint32_t u32Sum)
203	{
204	u32Sum += pUdpHdr->uh_sport
205	+ pUdpHdr->uh_dport
206	/+ pUdpHdr->uh_sum = 0 /
207	+ pUdpHdr->uh_ulen;
208	return u32Sum;
209	}
210
211
212	/**
213	* Adds the checksum of the UDP header to the intermediate checksum value.
214	*
215	* @returns 32-bit intermediary checksum value.
216	* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
217	* @param u32Sum The 32-bit intermediate checksum value.
218	*/
219	RTDECL(uint32_t) RTNetIPv4AddUDPChecksum(PCRTNETUDP pUdpHdr, uint32_t u32Sum)
220	{
221	return rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum);
222	}
223	RT_EXPORT_SYMBOL(RTNetIPv4AddUDPChecksum);
224
225
226	/**
227	* Adds the checksum of the TCP header to the intermediate checksum value [inlined].
228	*
229	* @returns 32-bit intermediary checksum value.
230	* @param pUdpHdr Pointer to the TCP header to checksum, network endian (big).
231	* Assums the caller has already validate it and made sure the
232	* entire header is present.
233	* @param u32Sum The 32-bit intermediate checksum value.
234	*/
235	DECLINLINE(uint32_t) rtNetIPv4AddTCPChecksum(PCRTNETTCP pTcpHdr, uint32_t u32Sum)
236	{
237	uint16_t const paw = (uint16_t const )pTcpHdr;
238	u32Sum += paw[0] /* th_sport */
239	+ paw[1] /* th_dport */
240	+ paw[2] /* th_seq */
241	+ paw[3] /* th_seq:16 */
242	+ paw[4] /* th_ack */
243	+ paw[5] /* th_ack:16 */
244	+ paw[6] /* th_off, th_x2, th_flags */
245	+ paw[7] /* th_win */
246	/+ paw[8] == 0 / /* th_sum */
247	+ paw[9]; /* th_urp */
248	if (pTcpHdr->th_off > RTNETTCP_MIN_LEN / 4)
249	{
250	/* this is a bit insane... (identical to the IPv4 header) */
251	switch (pTcpHdr->th_off)
252	{
253	case 6: u32Sum += paw[10] + paw[11]; break;
254	case 7: u32Sum += paw[10] + paw[11] + paw[12] + paw[13]; break;
255	case 8: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15]; break;
256	case 9: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break;
257	case 10: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break;
258	case 11: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21]; break;
259	case 12: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23]; break;
260	case 13: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25]; break;
261	case 14: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27]; break;
262	case 15: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27] + paw[28] + paw[29]; break;
263	default:
264	AssertFailed();
265	}
266	}
267
268	return u32Sum;
269	}
270
271
272	/**
273	* Adds the checksum of the TCP header to the intermediate checksum value.
274	*
275	* @returns 32-bit intermediary checksum value.
276	* @param pUdpHdr Pointer to the TCP header to checksum, network endian (big).
277	* Assums the caller has already validate it and made sure the
278	* entire header is present.
279	* @param u32Sum The 32-bit intermediate checksum value.
280	*/
281	RTDECL(uint32_t) RTNetIPv4AddTCPChecksum(PCRTNETTCP pTcpHdr, uint32_t u32Sum)
282	{
283	return rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum);
284	}
285	RT_EXPORT_SYMBOL(RTNetIPv4AddTCPChecksum);
286
287
288	/**
289	* Adds the checksum of the specified data segment to the intermediate checksum value [inlined].
290	*
291	* @returns 32-bit intermediary checksum value.
292	* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
293	* @param u32Sum The 32-bit intermediate checksum value.
294	* @param pfOdd This is used to keep track of odd bits, initialize to false
295	* when starting to checksum the data (aka text) after a TCP
296	* or UDP header (data never start at an odd offset).
297	*/
298	DECLINLINE(uint32_t) rtNetIPv4AddDataChecksum(void const pvData, size_t cbData, uint32_t u32Sum, bool pfOdd)
299	{
300	if (*pfOdd)
301	{
302	#ifdef RT_BIG_ENDIAN
303	/* there was an odd byte in the previous chunk, add the lower byte. */
304	u32Sum += (uint8_t )pvData;
305	#else
306	/* there was an odd byte in the previous chunk, add the upper byte. */
307	u32Sum += (uint32_t)(uint8_t )pvData << 8;
308	#endif
309	/* skip the byte. */
310	cbData--;
311	if (!cbData)
312	return u32Sum;
313	pvData = (uint8_t const *)pvData + 1;
314	}
315
316	/* iterate the data. */
317	uint16_t const pw = (uint16_t const )pvData;
318	while (cbData > 1)
319	{
320	u32Sum += *pw;
321	pw++;
322	cbData -= 2;
323	}
324
325	/* handle odd byte. */
326	if (cbData)
327	{
328	#ifdef RT_BIG_ENDIAN
329	u32Sum += (uint32_t)(uint8_t )pw << 8;
330	#else
331	u32Sum += (uint8_t )pw;
332	#endif
333	*pfOdd = true;
334	}
335	else
336	*pfOdd = false;
337	return u32Sum;
338	}
339
340	/**
341	* Adds the checksum of the specified data segment to the intermediate checksum value.
342	*
343	* @returns 32-bit intermediary checksum value.
344	* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
345	* @param u32Sum The 32-bit intermediate checksum value.
346	* @param pfOdd This is used to keep track of odd bits, initialize to false
347	* when starting to checksum the data (aka text) after a TCP
348	* or UDP header (data never start at an odd offset).
349	*/
350	RTDECL(uint32_t) RTNetIPv4AddDataChecksum(void const pvData, size_t cbData, uint32_t u32Sum, bool pfOdd)
351	{
352	return rtNetIPv4AddDataChecksum(pvData, cbData, u32Sum, pfOdd);
353	}
354	RT_EXPORT_SYMBOL(RTNetIPv4AddDataChecksum);
355
356
357	/**
358	* Finalizes a IPv4 checksum [inlined].
359	*
360	* @returns The checksum (network endian).
361	* @param u32Sum The 32-bit intermediate checksum value.
362	*/
363	DECLINLINE(uint16_t) rtNetIPv4FinalizeChecksum(uint32_t u32Sum)
364	{
365	/* 16-bit one complement fun */
366	u32Sum = (u32Sum >> 16) + (u32Sum & 0xffff); /* hi + low words */
367	u32Sum += u32Sum >> 16; /* carry */
368	return (uint16_t)~u32Sum;
369	}
370
371
372	/**
373	* Finalizes a IPv4 checksum.
374	*
375	* @returns The checksum (network endian).
376	* @param u32Sum The 32-bit intermediate checksum value.
377	*/
378	RTDECL(uint16_t) RTNetIPv4FinalizeChecksum(uint32_t u32Sum)
379	{
380	return rtNetIPv4FinalizeChecksum(u32Sum);
381	}
382	RT_EXPORT_SYMBOL(RTNetIPv4FinalizeChecksum);
383
384
385	/**
386	* Calculates the checksum for the UDP header given the IP header,
387	* UDP header and payload.
388	*
389	* @returns The checksum (network endian).
390	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
391	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
392	* @param pvData Pointer to the UDP payload. The size is taken from the
393	* UDP header and the caller is supposed to have validated
394	* this before calling.
395	*/
396	RTDECL(uint16_t) RTNetIPv4UDPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData)
397	{
398	uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr);
399	u32Sum = rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum);
400	bool fOdd = false;
401	u32Sum = rtNetIPv4AddDataChecksum(pvData, RT_BE2H_U16(pUdpHdr->uh_ulen) - sizeof(*pUdpHdr), u32Sum, &fOdd);
402	return rtNetIPv4FinalizeChecksum(u32Sum);
403	}
404	RT_EXPORT_SYMBOL(RTNetIPv4UDPChecksum);
405
406
407	/**
408	* Simple verficiation of an UDP packet size.
409	*
410	* @returns true if valid, false if invalid.
411	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
412	* This is assumed to be valid and the minimum size being mapped.
413	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
414	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
415	*/
416	DECLINLINE(bool) rtNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax)
417	{
418	/*
419	* Size validation.
420	*/
421	if (RT_UNLIKELY(cbPktMax < RTNETUDP_MIN_LEN))
422	return false;
423	size_t cb = RT_BE2H_U16(pUdpHdr->uh_ulen);
424	if (RT_UNLIKELY(cb > cbPktMax))
425	return false;
426	if (RT_UNLIKELY(cb > (size_t)(RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4)))
427	return false;
428	return true;
429	}
430
431
432	/**
433	* Simple verficiation of an UDP packet size.
434	*
435	* @returns true if valid, false if invalid.
436	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
437	* This is assumed to be valid and the minimum size being mapped.
438	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
439	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
440	*/
441	RTDECL(bool) RTNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax)
442	{
443	return rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax);
444	}
445	RT_EXPORT_SYMBOL(RTNetIPv4IsUDPSizeValid);
446
447
448	/**
449	* Simple verficiation of an UDP packet (size + checksum).
450	*
451	* @returns true if valid, false if invalid.
452	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
453	* This is assumed to be valid and the minimum size being mapped.
454	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
455	* @param pvData Pointer to the data, assuming it's one single segment
456	* and that cbPktMax - sizeof(RTNETUDP) is mapped here.
457	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
458	*/
459	RTDECL(bool) RTNetIPv4IsUDPValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData, size_t cbPktMax)
460	{
461	if (RT_UNLIKELY(!rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax)))
462	return false;
463	if (pUdpHdr->uh_sum)
464	{
465	uint16_t u16Sum = RTNetIPv4UDPChecksum(pIpHdr, pUdpHdr, pvData);
466	if (RT_UNLIKELY(pUdpHdr->uh_sum != u16Sum))
467	return false;
468	}
469	return true;
470	}
471	RT_EXPORT_SYMBOL(RTNetIPv4IsUDPValid);
472
473
474	/**
475	* Calculates the checksum for the TCP header given the IP header,
476	* TCP header and payload.
477	*
478	* @returns The checksum (network endian).
479	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
480	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
481	* @param pvData Pointer to the TCP payload. The size is taken from the
482	* TCP header and the caller is supposed to have validated
483	* this before calling.
484	* If NULL then we assume the data follows immediately after
485	* the TCP header.
486	*/
487	RTDECL(uint16_t) RTNetIPv4TCPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, void const *pvData)
488	{
489	uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr);
490	u32Sum = rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum);
491	bool fOdd = false;
492	size_t cbData = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4 - pTcpHdr->th_off * 4;
493	u32Sum = rtNetIPv4AddDataChecksum(pvData ? pvData : (uint8_t const )pTcpHdr + pTcpHdr->th_off 4,
494	cbData, u32Sum, &fOdd);
495	return rtNetIPv4FinalizeChecksum(u32Sum);
496	}
497	RT_EXPORT_SYMBOL(RTNetIPv4TCPChecksum);
498
499
500	/**
501	* Verficiation of a TCP header.
502	*
503	* @returns true if valid, false if invalid.
504	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
505	* This is assumed to be valid and the minimum size being mapped.
506	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
507	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
508	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
509	*/
510	DECLINLINE(bool) rtNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax)
511	{
512	Assert(cbPktMax >= cbHdrMax);
513
514	/*
515	* Size validations.
516	*/
517	if (RT_UNLIKELY(cbPktMax < RTNETTCP_MIN_LEN))
518	return false;
519	size_t cbTcpHdr = pTcpHdr->th_off * 4;
520	if (RT_UNLIKELY(cbTcpHdr > cbHdrMax))
521	return false;
522	size_t cbTcp = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4;
523	if (RT_UNLIKELY(cbTcp > cbPktMax))
524	return false;
525	return true;
526	}
527
528
529	/**
530	* Simple verficiation of an TCP packet size.
531	*
532	* @returns true if valid, false if invalid.
533	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
534	* This is assumed to be valid and the minimum size being mapped.
535	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
536	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
537	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
538	*/
539	RTDECL(bool) RTNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax)
540	{
541	return rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax);
542	}
543	RT_EXPORT_SYMBOL(RTNetIPv4IsTCPSizeValid);
544
545
546	/**
547	* Simple verficiation of an TCP packet (size + checksum).
548	*
549	* @returns true if valid, false if invalid.
550	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
551	* This is assumed to be valid and the minimum size being mapped.
552	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
553	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
554	* @param pvData Pointer to the data, assuming it's one single segment
555	* and that cbPktMax - sizeof(RTNETTCP) is mapped here.
556	* If NULL then we assume the data follows immediately after
557	* the TCP header.
558	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
559	*/
560	RTDECL(bool) RTNetIPv4IsTCPValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, void const *pvData, size_t cbPktMax)
561	{
562	if (RT_UNLIKELY(!rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax)))
563	return false;
564	uint16_t u16Sum = RTNetIPv4TCPChecksum(pIpHdr, pTcpHdr, pvData);
565	if (RT_UNLIKELY(pTcpHdr->th_sum != u16Sum))
566	return false;
567	return true;
568	}
569	RT_EXPORT_SYMBOL(RTNetIPv4IsTCPValid);
570
571
572	/**
573	* Minimal validation of a DHCP packet.
574	*
575	* This will fail on BOOTP packets (if sufficient data is supplied).
576	* It will not verify the source and destination ports, that's the
577	* caller's responsibility.
578	*
579	* This function will ASSUME that the hardware type is ethernet
580	* and use that for htype/hlen validation.
581	*
582	* @returns true if valid, false if invalid.
583	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
584	* This is assumed to be valid and fully mapped.
585	* @param pDhcp Pointer to the DHCP packet.
586	* This might not be the entire thing, see cbDhcp.
587	* @param cbDhcp The number of valid bytes that pDhcp points to.
588	* @param pMsgType Where to store the message type (if found).
589	* This will be set to 0 if not found and on failure.
590	*/
591	RTDECL(bool) RTNetIPv4IsDHCPValid(PCRTNETUDP pUdpHdr, PCRTNETBOOTP pDhcp, size_t cbDhcp, uint8_t *pMsgType)
592	{
593	AssertPtrNull(pMsgType);
594	if (pMsgType)
595	*pMsgType = 0;
596
597	/*
598	* Validate all the header fields we're able to...
599	*/
600	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_op) + sizeof(pDhcp->bp_op))
601	return true;
602	if (RT_UNLIKELY( pDhcp->bp_op != RTNETBOOTP_OP_REQUEST
603	&& pDhcp->bp_op != RTNETBOOTP_OP_REPLY))
604	return false;
605
606	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_htype) + sizeof(pDhcp->bp_htype))
607	return true;
608	if (RT_UNLIKELY(pDhcp->bp_htype != RTNET_ARP_ETHER))
609	return false;
610
611	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_hlen) + sizeof(pDhcp->bp_hlen))
612	return true;
613	if (RT_UNLIKELY(pDhcp->bp_hlen != sizeof(RTMAC)))
614	return false;
615
616	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_flags) + sizeof(pDhcp->bp_flags))
617	return true;
618	if (RT_UNLIKELY(RT_BE2H_U16(pDhcp->bp_flags) & ~(RTNET_DHCP_FLAGS_NO_BROADCAST)))
619	return false;
620
621	/*
622	* Check the DHCP cookie and make sure it isn't followed by an END option
623	* (because that seems to be indicating that it's BOOTP and not DHCP).
624	*/
625	ssize_t cbLeft = (ssize_t)cbDhcp - RT_OFFSETOF(RTNETBOOTP, bp_vend.Dhcp.dhcp_cookie) + sizeof(pDhcp->bp_vend.Dhcp.dhcp_cookie);
626	if (cbLeft < 0)
627	return true;
628	if (RT_UNLIKELY(RT_BE2H_U32(pDhcp->bp_vend.Dhcp.dhcp_cookie) != RTNET_DHCP_COOKIE))
629	return false;
630	if (cbLeft < 1)
631	return true;
632	PCRTNETDHCPOPT pOpt = (PCRTNETDHCPOPT)&pDhcp->bp_vend.Dhcp.dhcp_opts[0];
633	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END)
634	return false;
635
636	/*
637	* Scan the options until we find the message type or run out of message.
638	*
639	* We're not strict about termination (END) for many reasons, however,
640	* we don't accept END without MSG_TYPE.
641	*/
642	uint8_t MsgType = 0;
643	while (cbLeft > 0)
644	{
645	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END)
646	{
647	/* Fail if no MSG_TYPE. */
648	if (!MsgType)
649	return false;
650	break;
651	}
652	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_PAD)
653	{
654	pOpt = (PCRTNETDHCPOPT)((uint8_t const *)pOpt + 1);
655	cbLeft--;
656	}
657	else
658	{
659	switch (pOpt->dhcp_opt)
660	{
661	case RTNET_DHCP_OPT_MSG_TYPE:
662	{
663	if (cbLeft < 3)
664	return true;
665	MsgType = (const uint8_t )(pOpt + 1);
666	switch (MsgType)
667	{
668	case RTNET_DHCP_MT_DISCOVER:
669	case RTNET_DHCP_MT_OFFER:
670	case RTNET_DHCP_MT_REQUEST:
671	case RTNET_DHCP_MT_DECLINE:
672	case RTNET_DHCP_MT_ACK:
673	case RTNET_DHCP_MT_NAC:
674	case RTNET_DHCP_MT_RELEASE:
675	case RTNET_DHCP_MT_INFORM:
676	break;
677
678	default:
679	/* we don't know this message type, fail. */
680	return false;
681	}
682
683	/* Found a known message type, consider the job done. */
684	if (pMsgType)
685	*pMsgType = MsgType;
686	return true;
687	}
688	}
689
690	/* Skip the option. */
691	cbLeft -= pOpt->dhcp_len + sizeof(*pOpt);
692	pOpt = (PCRTNETDHCPOPT)((uint8_t const )pOpt + pOpt->dhcp_len + sizeof(pOpt));
693	}
694	}
695
696	return true;
697	}
698	RT_EXPORT_SYMBOL(RTNetIPv4IsDHCPValid);
699

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source: vbox/trunk/src/VBox/Runtime/common/checksum/ipv4.cpp@ 24873

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