ipv4.cpp@ 25659

Last change on this file since 25659 was 25645, checked in by vboxsync, 15 years ago
IPRT,DoxyFile.Core: Mopped up the errors in the IPRT doxygen run.
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1	/* $Id: ipv4.cpp 25645 2010-01-05 09:29:31Z 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 pTcpHdr Pointer to the TCP header to checksum, network
231	* endian (big). Assums the caller has already validate
232	* it and made sure the 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 pTcpHdr Pointer to the TCP header to checksum, network
277	* endian (big). Assums the caller has already validate
278	* it and made sure the 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 pvData Pointer to the data that should be checksummed.
293	* @param cbData The number of bytes to checksum.
294	* @param u32Sum The 32-bit intermediate checksum value.
295	* @param pfOdd This is used to keep track of odd bits, initialize to false
296	* when starting to checksum the data (aka text) after a TCP
297	* or UDP header (data never start at an odd offset).
298	*/
299	DECLINLINE(uint32_t) rtNetIPv4AddDataChecksum(void const pvData, size_t cbData, uint32_t u32Sum, bool pfOdd)
300	{
301	if (*pfOdd)
302	{
303	#ifdef RT_BIG_ENDIAN
304	/* there was an odd byte in the previous chunk, add the lower byte. */
305	u32Sum += (uint8_t )pvData;
306	#else
307	/* there was an odd byte in the previous chunk, add the upper byte. */
308	u32Sum += (uint32_t)(uint8_t )pvData << 8;
309	#endif
310	/* skip the byte. */
311	cbData--;
312	if (!cbData)
313	return u32Sum;
314	pvData = (uint8_t const *)pvData + 1;
315	}
316
317	/* iterate the data. */
318	uint16_t const pw = (uint16_t const )pvData;
319	while (cbData > 1)
320	{
321	u32Sum += *pw;
322	pw++;
323	cbData -= 2;
324	}
325
326	/* handle odd byte. */
327	if (cbData)
328	{
329	#ifdef RT_BIG_ENDIAN
330	u32Sum += (uint32_t)(uint8_t )pw << 8;
331	#else
332	u32Sum += (uint8_t )pw;
333	#endif
334	*pfOdd = true;
335	}
336	else
337	*pfOdd = false;
338	return u32Sum;
339	}
340
341	/**
342	* Adds the checksum of the specified data segment to the intermediate checksum value.
343	*
344	* @returns 32-bit intermediary checksum value.
345	* @param pvData The data bits to checksum.
346	* @param cbData The number of bytes to checksum.
347	* @param u32Sum The 32-bit intermediate checksum value.
348	* @param pfOdd This is used to keep track of odd bits, initialize to false
349	* when starting to checksum the data (aka text) after a TCP
350	* or UDP header (data never start at an odd offset).
351	*/
352	RTDECL(uint32_t) RTNetIPv4AddDataChecksum(void const pvData, size_t cbData, uint32_t u32Sum, bool pfOdd)
353	{
354	return rtNetIPv4AddDataChecksum(pvData, cbData, u32Sum, pfOdd);
355	}
356	RT_EXPORT_SYMBOL(RTNetIPv4AddDataChecksum);
357
358
359	/**
360	* Finalizes a IPv4 checksum [inlined].
361	*
362	* @returns The checksum (network endian).
363	* @param u32Sum The 32-bit intermediate checksum value.
364	*/
365	DECLINLINE(uint16_t) rtNetIPv4FinalizeChecksum(uint32_t u32Sum)
366	{
367	/* 16-bit one complement fun */
368	u32Sum = (u32Sum >> 16) + (u32Sum & 0xffff); /* hi + low words */
369	u32Sum += u32Sum >> 16; /* carry */
370	return (uint16_t)~u32Sum;
371	}
372
373
374	/**
375	* Finalizes a IPv4 checksum.
376	*
377	* @returns The checksum (network endian).
378	* @param u32Sum The 32-bit intermediate checksum value.
379	*/
380	RTDECL(uint16_t) RTNetIPv4FinalizeChecksum(uint32_t u32Sum)
381	{
382	return rtNetIPv4FinalizeChecksum(u32Sum);
383	}
384	RT_EXPORT_SYMBOL(RTNetIPv4FinalizeChecksum);
385
386
387	/**
388	* Calculates the checksum for the UDP header given the IP header,
389	* UDP header and payload.
390	*
391	* @returns The checksum (network endian).
392	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
393	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
394	* @param pvData Pointer to the UDP payload. The size is taken from the
395	* UDP header and the caller is supposed to have validated
396	* this before calling.
397	*/
398	RTDECL(uint16_t) RTNetIPv4UDPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData)
399	{
400	uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr);
401	u32Sum = rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum);
402	bool fOdd = false;
403	u32Sum = rtNetIPv4AddDataChecksum(pvData, RT_BE2H_U16(pUdpHdr->uh_ulen) - sizeof(*pUdpHdr), u32Sum, &fOdd);
404	return rtNetIPv4FinalizeChecksum(u32Sum);
405	}
406	RT_EXPORT_SYMBOL(RTNetIPv4UDPChecksum);
407
408
409	/**
410	* Simple verficiation of an UDP packet size.
411	*
412	* @returns true if valid, false if invalid.
413	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
414	* This is assumed to be valid and the minimum size being mapped.
415	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
416	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
417	*/
418	DECLINLINE(bool) rtNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax)
419	{
420	/*
421	* Size validation.
422	*/
423	if (RT_UNLIKELY(cbPktMax < RTNETUDP_MIN_LEN))
424	return false;
425	size_t cb = RT_BE2H_U16(pUdpHdr->uh_ulen);
426	if (RT_UNLIKELY(cb > cbPktMax))
427	return false;
428	if (RT_UNLIKELY(cb > (size_t)(RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4)))
429	return false;
430	return true;
431	}
432
433
434	/**
435	* Simple verficiation of an UDP packet size.
436	*
437	* @returns true if valid, false if invalid.
438	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
439	* This is assumed to be valid and the minimum size being mapped.
440	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
441	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
442	*/
443	RTDECL(bool) RTNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax)
444	{
445	return rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax);
446	}
447	RT_EXPORT_SYMBOL(RTNetIPv4IsUDPSizeValid);
448
449
450	/**
451	* Simple verficiation of an UDP packet (size + checksum).
452	*
453	* @returns true if valid, false if invalid.
454	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
455	* This is assumed to be valid and the minimum size being mapped.
456	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
457	* @param pvData Pointer to the data, assuming it's one single segment
458	* and that cbPktMax - sizeof(RTNETUDP) is mapped here.
459	* @param cbPktMax The max UDP packet size, UDP header and payload (data).
460	*/
461	RTDECL(bool) RTNetIPv4IsUDPValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData, size_t cbPktMax)
462	{
463	if (RT_UNLIKELY(!rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax)))
464	return false;
465	if (pUdpHdr->uh_sum)
466	{
467	uint16_t u16Sum = RTNetIPv4UDPChecksum(pIpHdr, pUdpHdr, pvData);
468	if (RT_UNLIKELY(pUdpHdr->uh_sum != u16Sum))
469	return false;
470	}
471	return true;
472	}
473	RT_EXPORT_SYMBOL(RTNetIPv4IsUDPValid);
474
475
476	/**
477	* Calculates the checksum for the TCP header given the IP header,
478	* TCP header and payload.
479	*
480	* @returns The checksum (network endian).
481	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
482	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
483	* @param pvData Pointer to the TCP payload. The size is taken from the
484	* TCP header and the caller is supposed to have validated
485	* this before calling.
486	* If NULL then we assume the data follows immediately after
487	* the TCP header.
488	*/
489	RTDECL(uint16_t) RTNetIPv4TCPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, void const *pvData)
490	{
491	uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr);
492	u32Sum = rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum);
493	bool fOdd = false;
494	size_t cbData = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4 - pTcpHdr->th_off * 4;
495	u32Sum = rtNetIPv4AddDataChecksum(pvData ? pvData : (uint8_t const )pTcpHdr + pTcpHdr->th_off 4,
496	cbData, u32Sum, &fOdd);
497	return rtNetIPv4FinalizeChecksum(u32Sum);
498	}
499	RT_EXPORT_SYMBOL(RTNetIPv4TCPChecksum);
500
501
502	/**
503	* Verficiation of a TCP header.
504	*
505	* @returns true if valid, false if invalid.
506	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
507	* This is assumed to be valid and the minimum size being mapped.
508	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
509	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
510	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
511	*/
512	DECLINLINE(bool) rtNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax)
513	{
514	Assert(cbPktMax >= cbHdrMax);
515
516	/*
517	* Size validations.
518	*/
519	if (RT_UNLIKELY(cbPktMax < RTNETTCP_MIN_LEN))
520	return false;
521	size_t cbTcpHdr = pTcpHdr->th_off * 4;
522	if (RT_UNLIKELY(cbTcpHdr > cbHdrMax))
523	return false;
524	size_t cbTcp = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4;
525	if (RT_UNLIKELY(cbTcp > cbPktMax))
526	return false;
527	return true;
528	}
529
530
531	/**
532	* Simple verficiation of an TCP packet size.
533	*
534	* @returns true if valid, false if invalid.
535	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
536	* This is assumed to be valid and the minimum size being mapped.
537	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
538	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
539	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
540	*/
541	RTDECL(bool) RTNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax)
542	{
543	return rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax);
544	}
545	RT_EXPORT_SYMBOL(RTNetIPv4IsTCPSizeValid);
546
547
548	/**
549	* Simple verficiation of an TCP packet (size + checksum).
550	*
551	* @returns true if valid, false if invalid.
552	* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
553	* This is assumed to be valid and the minimum size being mapped.
554	* @param pTcpHdr Pointer to the TCP header, in network endian (big).
555	* @param cbHdrMax The max TCP header size (what pTcpHdr points to).
556	* @param pvData Pointer to the data, assuming it's one single segment
557	* and that cbPktMax - sizeof(RTNETTCP) is mapped here.
558	* If NULL then we assume the data follows immediately after
559	* the TCP header.
560	* @param cbPktMax The max TCP packet size, TCP header and payload (data).
561	*/
562	RTDECL(bool) RTNetIPv4IsTCPValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, void const *pvData, size_t cbPktMax)
563	{
564	if (RT_UNLIKELY(!rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax)))
565	return false;
566	uint16_t u16Sum = RTNetIPv4TCPChecksum(pIpHdr, pTcpHdr, pvData);
567	if (RT_UNLIKELY(pTcpHdr->th_sum != u16Sum))
568	return false;
569	return true;
570	}
571	RT_EXPORT_SYMBOL(RTNetIPv4IsTCPValid);
572
573
574	/**
575	* Minimal validation of a DHCP packet.
576	*
577	* This will fail on BOOTP packets (if sufficient data is supplied).
578	* It will not verify the source and destination ports, that's the
579	* caller's responsibility.
580	*
581	* This function will ASSUME that the hardware type is ethernet
582	* and use that for htype/hlen validation.
583	*
584	* @returns true if valid, false if invalid.
585	* @param pUdpHdr Pointer to the UDP header, in network endian (big).
586	* This is assumed to be valid and fully mapped.
587	* @param pDhcp Pointer to the DHCP packet.
588	* This might not be the entire thing, see cbDhcp.
589	* @param cbDhcp The number of valid bytes that pDhcp points to.
590	* @param pMsgType Where to store the message type (if found).
591	* This will be set to 0 if not found and on failure.
592	*/
593	RTDECL(bool) RTNetIPv4IsDHCPValid(PCRTNETUDP pUdpHdr, PCRTNETBOOTP pDhcp, size_t cbDhcp, uint8_t *pMsgType)
594	{
595	AssertPtrNull(pMsgType);
596	if (pMsgType)
597	*pMsgType = 0;
598
599	/*
600	* Validate all the header fields we're able to...
601	*/
602	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_op) + sizeof(pDhcp->bp_op))
603	return true;
604	if (RT_UNLIKELY( pDhcp->bp_op != RTNETBOOTP_OP_REQUEST
605	&& pDhcp->bp_op != RTNETBOOTP_OP_REPLY))
606	return false;
607
608	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_htype) + sizeof(pDhcp->bp_htype))
609	return true;
610	if (RT_UNLIKELY(pDhcp->bp_htype != RTNET_ARP_ETHER))
611	return false;
612
613	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_hlen) + sizeof(pDhcp->bp_hlen))
614	return true;
615	if (RT_UNLIKELY(pDhcp->bp_hlen != sizeof(RTMAC)))
616	return false;
617
618	if (cbDhcp < RT_OFFSETOF(RTNETBOOTP, bp_flags) + sizeof(pDhcp->bp_flags))
619	return true;
620	if (RT_UNLIKELY(RT_BE2H_U16(pDhcp->bp_flags) & ~(RTNET_DHCP_FLAGS_NO_BROADCAST)))
621	return false;
622
623	/*
624	* Check the DHCP cookie and make sure it isn't followed by an END option
625	* (because that seems to be indicating that it's BOOTP and not DHCP).
626	*/
627	ssize_t cbLeft = (ssize_t)cbDhcp - RT_OFFSETOF(RTNETBOOTP, bp_vend.Dhcp.dhcp_cookie) + sizeof(pDhcp->bp_vend.Dhcp.dhcp_cookie);
628	if (cbLeft < 0)
629	return true;
630	if (RT_UNLIKELY(RT_BE2H_U32(pDhcp->bp_vend.Dhcp.dhcp_cookie) != RTNET_DHCP_COOKIE))
631	return false;
632	if (cbLeft < 1)
633	return true;
634	PCRTNETDHCPOPT pOpt = (PCRTNETDHCPOPT)&pDhcp->bp_vend.Dhcp.dhcp_opts[0];
635	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END)
636	return false;
637
638	/*
639	* Scan the options until we find the message type or run out of message.
640	*
641	* We're not strict about termination (END) for many reasons, however,
642	* we don't accept END without MSG_TYPE.
643	*/
644	uint8_t MsgType = 0;
645	while (cbLeft > 0)
646	{
647	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END)
648	{
649	/* Fail if no MSG_TYPE. */
650	if (!MsgType)
651	return false;
652	break;
653	}
654	if (pOpt->dhcp_opt == RTNET_DHCP_OPT_PAD)
655	{
656	pOpt = (PCRTNETDHCPOPT)((uint8_t const *)pOpt + 1);
657	cbLeft--;
658	}
659	else
660	{
661	switch (pOpt->dhcp_opt)
662	{
663	case RTNET_DHCP_OPT_MSG_TYPE:
664	{
665	if (cbLeft < 3)
666	return true;
667	MsgType = (const uint8_t )(pOpt + 1);
668	switch (MsgType)
669	{
670	case RTNET_DHCP_MT_DISCOVER:
671	case RTNET_DHCP_MT_OFFER:
672	case RTNET_DHCP_MT_REQUEST:
673	case RTNET_DHCP_MT_DECLINE:
674	case RTNET_DHCP_MT_ACK:
675	case RTNET_DHCP_MT_NAC:
676	case RTNET_DHCP_MT_RELEASE:
677	case RTNET_DHCP_MT_INFORM:
678	break;
679
680	default:
681	/* we don't know this message type, fail. */
682	return false;
683	}
684
685	/* Found a known message type, consider the job done. */
686	if (pMsgType)
687	*pMsgType = MsgType;
688	return true;
689	}
690	}
691
692	/* Skip the option. */
693	cbLeft -= pOpt->dhcp_len + sizeof(*pOpt);
694	pOpt = (PCRTNETDHCPOPT)((uint8_t const )pOpt + pOpt->dhcp_len + sizeof(pOpt));
695	}
696	}
697
698	return true;
699	}
700	RT_EXPORT_SYMBOL(RTNetIPv4IsDHCPValid);
701

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source: vbox/trunk/src/VBox/Runtime/common/checksum/ipv4.cpp@ 25659

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