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
|
/* Copyright (C) 2007-2013 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>
*/
#ifndef __DECODE_UDP_H__
#define __DECODE_UDP_H__
#define UDP_HEADER_LEN 8
/* XXX RAW* needs to be really 'raw', so no ntohs there */
#define UDP_GET_RAW_LEN(udph) ntohs((udph)->uh_len)
#define UDP_GET_RAW_SRC_PORT(udph) ntohs((udph)->uh_sport)
#define UDP_GET_RAW_DST_PORT(udph) ntohs((udph)->uh_dport)
#define UDP_GET_LEN(p) UDP_GET_RAW_LEN(p->udph)
#define UDP_GET_SRC_PORT(p) UDP_GET_RAW_SRC_PORT(p->udph)
#define UDP_GET_DST_PORT(p) UDP_GET_RAW_DST_PORT(p->udph)
/* UDP header structure */
typedef struct UDPHdr_
{
uint16_t uh_sport; /* source port */
uint16_t uh_dport; /* destination port */
uint16_t uh_len; /* length */
uint16_t uh_sum; /* checksum */
} __attribute__((__packed__)) UDPHdr;
typedef struct UDPVars_
{
} UDPVars;
#define CLEAR_UDP_PACKET(p) do { \
(p)->udph = NULL; \
(p)->level4_comp_csum = -1; \
} while (0)
void DecodeUDPV4RegisterTests(void);
/** ------ Inline function ------ */
static inline uint16_t UDPV4CalculateChecksum(uint16_t *, uint16_t *, uint16_t);
static inline uint16_t UDPV6CalculateChecksum(uint16_t *, uint16_t *, uint16_t);
/**
* \brief Calculates the checksum for the UDP packet
*
* \param shdr Pointer to source address field from the IP packet. Used as a
* part of the psuedoheader for computing the checksum
* \param pkt Pointer to the start of the UDP packet
* \param hlen Total length of the UDP packet(header + payload)
*
* \retval csum Checksum for the UDP packet
*/
static inline uint16_t UDPV4CalculateChecksum(uint16_t *shdr, uint16_t *pkt,
uint16_t tlen)
{
uint16_t pad = 0;
uint32_t csum = shdr[0];
csum += shdr[1] + shdr[2] + shdr[3] + htons(17) + htons(tlen);
csum += pkt[0] + pkt[1] + pkt[2];
tlen -= 8;
pkt += 4;
while (tlen >= 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];
tlen -= 32;
pkt += 16;
}
while(tlen >= 8) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
tlen -= 8;
pkt += 4;
}
while(tlen >= 4) {
csum += pkt[0] + pkt[1];
tlen -= 4;
pkt += 2;
}
while (tlen > 1) {
csum += pkt[0];
pkt += 1;
tlen -= 2;
}
if (tlen == 1) {
*(uint8_t *)(&pad) = (*(uint8_t *)pkt);
csum += pad;
}
csum = (csum >> 16) + (csum & 0x0000FFFF);
csum += (csum >> 16);
uint16_t csum_u16 = (uint16_t)~csum;
if (csum_u16 == 0)
return 0xFFFF;
else
return csum_u16;
}
/**
* \brief Calculates the checksum for the UDP packet
*
* \param shdr Pointer to source address field from the IPV6 packet. Used as a
* part of the psuedoheader for computing the checksum
* \param pkt Pointer to the start of the UDP packet
* \param tlen Total length of the UDP packet(header + payload)
*
* \retval csum Checksum for the UDP packet
*/
static inline uint16_t UDPV6CalculateChecksum(uint16_t *shdr, uint16_t *pkt,
uint16_t tlen)
{
uint16_t pad = 0;
uint32_t csum = shdr[0];
csum += shdr[1] + shdr[2] + shdr[3] + shdr[4] + shdr[5] + shdr[6] +
shdr[7] + shdr[8] + shdr[9] + shdr[10] + shdr[11] + shdr[12] +
shdr[13] + shdr[14] + shdr[15] + htons(17) + htons(tlen);
csum += pkt[0] + pkt[1] + pkt[2];
tlen -= 8;
pkt += 4;
while (tlen >= 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];
tlen -= 32;
pkt += 16;
}
while(tlen >= 8) {
csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
tlen -= 8;
pkt += 4;
}
while(tlen >= 4) {
csum += pkt[0] + pkt[1];
tlen -= 4;
pkt += 2;
}
while (tlen > 1) {
csum += pkt[0];
pkt += 1;
tlen -= 2;
}
if (tlen == 1) {
*(uint8_t *)(&pad) = (*(uint8_t *)pkt);
csum += pad;
}
csum = (csum >> 16) + (csum & 0x0000FFFF);
csum += (csum >> 16);
uint16_t csum_u16 = (uint16_t)~csum;
if (csum_u16 == 0)
return 0xFFFF;
else
return csum_u16;
}
#endif /* __DECODE_UDP_H__ */
|
