1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
|
/* Copyright (C) 2007-2022 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
* \author Brian Rectanus <brectanu@gmail.com>
*/
#ifndef __DECODE_IPV4_H__
#define __DECODE_IPV4_H__
#define IPV4_HEADER_LEN 20 /**< Header length */
#define IPV4_OPTMAX 40 /**< Max options length */
#define IPV4_MAXPACKET_LEN 65535 /**< Maximum packet size */
/** IP Option Types */
#define IPV4_OPT_EOL 0x00 /**< Option: End of List */
#define IPV4_OPT_NOP 0x01 /**< Option: No op */
#define IPV4_OPT_RR 0x07 /**< Option: Record Route */
#define IPV4_OPT_QS 0x19 /**< Option: Quick Start */
#define IPV4_OPT_TS 0x44 /**< Option: Timestamp */
#define IPV4_OPT_SEC 0x82 /**< Option: Security */
#define IPV4_OPT_LSRR 0x83 /**< Option: Loose Source Route */
#define IPV4_OPT_ESEC 0x85 /**< Option: Extended Security */
#define IPV4_OPT_CIPSO 0x86 /**< Option: Commercial IP Security */
#define IPV4_OPT_SID 0x88 /**< Option: Stream Identifier */
#define IPV4_OPT_SSRR 0x89 /**< Option: Strict Source Route */
#define IPV4_OPT_RTRALT 0x94 /**< Option: Router Alert */
/** IP Option Lengths (fixed) */
#define IPV4_OPT_SID_LEN 4 /**< SID Option Fixed Length */
#define IPV4_OPT_RTRALT_LEN 4 /**< RTRALT Option Fixed Length */
/** IP Option Lengths (variable) */
#define IPV4_OPT_SEC_MIN 3 /**< SEC, ESEC Option Min Length */
#define IPV4_OPT_ROUTE_MIN 3 /**< RR, SRR, LTRR Option Min Length */
#define IPV4_OPT_QS_MIN 8 /**< QS Option Min Length */
#define IPV4_OPT_TS_MIN 5 /**< TS Option Min Length */
#define IPV4_OPT_CIPSO_MIN 10 /**< CIPSO Option Min Length */
/** IP Option fields */
#define IPV4_OPTS ip4vars.ip_opts
#define IPV4_OPTS_CNT ip4vars.ip_opt_cnt
typedef struct IPV4Opt_ {
/** \todo We may want to break type up into its 3 fields
* as the reassembler may want to know which options
* must be copied to each fragment.
*/
uint8_t type; /**< option type */
uint8_t len; /**< option length (type+len+data) */
const uint8_t *data; /**< option data */
} IPV4Opt;
typedef struct IPV4Hdr_
{
uint8_t ip_verhl; /**< version & header length */
uint8_t ip_tos; /**< type of service */
uint16_t ip_len; /**< length */
uint16_t ip_id; /**< id */
uint16_t ip_off; /**< frag offset */
uint8_t ip_ttl; /**< time to live */
uint8_t ip_proto; /**< protocol (tcp, udp, etc) */
uint16_t ip_csum; /**< checksum */
union {
struct {
struct in_addr ip_src;/**< source address */
struct in_addr ip_dst;/**< destination address */
} ip4_un1;
uint16_t ip_addrs[4];
} ip4_hdrun1;
} IPV4Hdr;
#define s_ip_src ip4_hdrun1.ip4_un1.ip_src
#define s_ip_dst ip4_hdrun1.ip4_un1.ip_dst
#define s_ip_addrs ip4_hdrun1.ip_addrs
#define IPV4_GET_RAW_VER(ip4h) (((ip4h)->ip_verhl & 0xf0) >> 4)
#define IPV4_GET_RAW_HLEN(ip4h) ((ip4h)->ip_verhl & 0x0f)
#define IPV4_GET_RAW_IPTOS(ip4h) ((ip4h)->ip_tos)
#define IPV4_GET_RAW_IPLEN(ip4h) ((ip4h)->ip_len)
#define IPV4_GET_RAW_IPID(ip4h) ((ip4h)->ip_id)
#define IPV4_GET_RAW_IPOFFSET(ip4h) ((ip4h)->ip_off)
#define IPV4_GET_RAW_IPTTL(ip4h) ((ip4h)->ip_ttl)
#define IPV4_GET_RAW_IPPROTO(ip4h) ((ip4h)->ip_proto)
#define IPV4_GET_RAW_IPSRC(ip4h) ((ip4h)->s_ip_src)
#define IPV4_GET_RAW_IPDST(ip4h) ((ip4h)->s_ip_dst)
/** return the raw (directly from the header) src ip as uint32_t */
#define IPV4_GET_RAW_IPSRC_U32(ip4h) (uint32_t)((ip4h)->s_ip_src.s_addr)
/** return the raw (directly from the header) dst ip as uint32_t */
#define IPV4_GET_RAW_IPDST_U32(ip4h) (uint32_t)((ip4h)->s_ip_dst.s_addr)
/* we need to change them as well as get them */
#define IPV4_SET_RAW_VER(ip4h, value) ((ip4h)->ip_verhl = (((ip4h)->ip_verhl & 0x0f) | (value << 4)))
#define IPV4_SET_RAW_HLEN(ip4h, value) ((ip4h)->ip_verhl = (((ip4h)->ip_verhl & 0xf0) | (value & 0x0f)))
#define IPV4_SET_RAW_IPTOS(ip4h, value) ((ip4h)->ip_tos = value)
#define IPV4_SET_RAW_IPLEN(ip4h, value) ((ip4h)->ip_len = value)
#define IPV4_SET_RAW_IPPROTO(ip4h, value) ((ip4h)->ip_proto = value)
/* ONLY call these functions after making sure that:
* 1. p->ip4h is set
* 2. p->ip4h is valid (len is correct)
*/
#define IPV4_GET_VER(p) \
IPV4_GET_RAW_VER((p)->ip4h)
#define IPV4_GET_HLEN(p) ((uint8_t)(IPV4_GET_RAW_HLEN((p)->ip4h) << 2))
#define IPV4_GET_IPTOS(p) \
IPV4_GET_RAW_IPTOS((p)->ip4h)
#define IPV4_GET_IPLEN(p) \
(SCNtohs(IPV4_GET_RAW_IPLEN((p)->ip4h)))
#define IPV4_GET_IPID(p) \
(SCNtohs(IPV4_GET_RAW_IPID((p)->ip4h)))
/* _IPV4_GET_IPOFFSET: get the content of the offset header field in host order */
#define _IPV4_GET_IPOFFSET(p) \
(SCNtohs(IPV4_GET_RAW_IPOFFSET((p)->ip4h)))
/* IPV4_GET_IPOFFSET: get the final offset */
#define IPV4_GET_IPOFFSET(p) \
(_IPV4_GET_IPOFFSET(p) & 0x1fff)
/* IPV4_GET_RF: get the RF flag. Use _IPV4_GET_IPOFFSET to save a SCNtohs call. */
#define IPV4_GET_RF(p) \
(uint8_t)((_IPV4_GET_IPOFFSET((p)) & 0x8000) >> 15)
/* IPV4_GET_DF: get the DF flag. Use _IPV4_GET_IPOFFSET to save a SCNtohs call. */
#define IPV4_GET_DF(p) \
(uint8_t)((_IPV4_GET_IPOFFSET((p)) & 0x4000) >> 14)
/* IPV4_GET_MF: get the MF flag. Use _IPV4_GET_IPOFFSET to save a SCNtohs call. */
#define IPV4_GET_MF(p) \
(uint8_t)((_IPV4_GET_IPOFFSET((p)) & 0x2000) >> 13)
#define IPV4_GET_IPTTL(p) \
IPV4_GET_RAW_IPTTL(p->ip4h)
#define IPV4_GET_IPPROTO(p) \
IPV4_GET_RAW_IPPROTO((p)->ip4h)
#define CLEAR_IPV4_PACKET(p) do { \
(p)->ip4h = NULL; \
(p)->level3_comp_csum = -1; \
memset(&p->ip4vars, 0x00, sizeof(p->ip4vars)); \
} while (0)
#define IPV4_OPT_FLAG_EOL BIT_U16(1)
#define IPV4_OPT_FLAG_NOP BIT_U16(2)
#define IPV4_OPT_FLAG_RR BIT_U16(3)
#define IPV4_OPT_FLAG_TS BIT_U16(4)
#define IPV4_OPT_FLAG_QS BIT_U16(5)
#define IPV4_OPT_FLAG_LSRR BIT_U16(6)
#define IPV4_OPT_FLAG_SSRR BIT_U16(7)
#define IPV4_OPT_FLAG_SID BIT_U16(8)
#define IPV4_OPT_FLAG_SEC BIT_U16(9)
#define IPV4_OPT_FLAG_CIPSO BIT_U16(10)
#define IPV4_OPT_FLAG_RTRALT BIT_U16(11)
#define IPV4_OPT_FLAG_ESEC BIT_U16(12)
/* helper structure with parsed ipv4 info */
typedef struct IPV4Vars_
{
int32_t comp_csum; /* checksum computed over the ipv4 packet */
uint16_t opt_cnt;
uint16_t opts_set;
} IPV4Vars;
void DecodeIPV4RegisterTests(void);
/** ----- Inline functions ----- */
/**
* \brief Calculate or validate the checksum for the IP packet
*
* \param pkt Pointer to the start of the IP packet
* \param hlen Length of the IP header
* \param init The current checksum if validating, 0 if generating.
*
* \retval csum For validation 0 will be returned for success, for calculation
* this will be the checksum.
*/
static inline uint16_t IPV4Checksum(const uint16_t *pkt, uint16_t hlen, uint16_t init)
{
uint32_t csum = init;
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[6] + pkt[7] +
pkt[8] + pkt[9];
hlen -= 20;
pkt += 10;
if (hlen == 0) {
;
} else if (hlen == 4) {
csum += pkt[0] + pkt[1];
} else if (hlen == 8) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
} else if (hlen == 12) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5];
} else if (hlen == 16) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7];
} else if (hlen == 20) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9];
} else if (hlen == 24) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11];
} else if (hlen == 28) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13];
} else if (hlen == 32) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
pkt[14] + pkt[15];
} else if (hlen == 36) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
pkt[14] + pkt[15] + pkt[16] + pkt[17];
} else if (hlen == 40) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
pkt[14] + pkt[15] + pkt[16] + pkt[17] + pkt[18] + pkt[19];
}
csum = (csum >> 16) + (csum & 0x0000FFFF);
csum += (csum >> 16);
return (uint16_t) ~csum;
}
#endif /* __DECODE_IPV4_H__ */
|
