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
|
/*
* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
*
* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the Internet Initiative Japan. The name of the
* IIJ may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $FreeBSD$
*
* TODO:
*/
/* Known protocols - f_proto */
#define P_NONE 0
#define P_TCP 1
#define P_UDP 2
#define P_ICMP 3
#ifdef IPPROTO_OSPFIGP
#define P_OSPF 4
#endif
#define P_IGMP 5
#ifdef IPPROTO_GRE
#define P_GRE 6
#endif
/* Operations - f_srcop, f_dstop */
#define OP_NONE 0
#define OP_EQ 1
#define OP_GT 2
#define OP_LT 3
/* srctype or dsttype */
#define T_ADDR 0
#define T_MYADDR 1
#define T_HISADDR 2
/*
* There's a struct filterent for each possible filter rule. The
* layout is designed to minimise size (there are 4 * MAXFILTERS of
* them) - which is also conveniently a power of 2 (32 bytes) on
* architectures where sizeof(int)==4 (this makes indexing faster).
*
* f_action and f_proto only need to be 6 and 3 bits, respectively,
* but making them 8 bits allows them to be efficently accessed using
* byte operations as well as allowing space for future expansion
* (expanding MAXFILTERS or converting f_proto IPPROTO_... values).
*
* Note that there are four free bits in the initial word for future
* extensions.
*/
struct filterent {
unsigned f_action : 8; /* Filtering action: goto or A_... */
unsigned f_proto : 8; /* Protocol: P_... */
unsigned f_srcop : 2; /* Source port operation: OP_... */
unsigned f_dstop : 2; /* Destination port operation: OP_... */
unsigned f_srctype : 2; /* T_ value of src */
unsigned f_dsttype : 2; /* T_ value of dst */
unsigned f_estab : 1; /* Check TCP ACK bit */
unsigned f_syn : 1; /* Check TCP SYN bit */
unsigned f_finrst : 1; /* Check TCP FIN/RST bits */
unsigned f_invert : 1; /* true to complement match */
struct in_range f_src; /* Source address and mask */
struct in_range f_dst; /* Destination address and mask */
u_short f_srcport; /* Source port, compared with f_srcop */
u_short f_dstport; /* Destination port, compared with f_dstop */
};
#define MAXFILTERS 40 /* in each filter set */
/* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */
#define A_NONE (MAXFILTERS)
#define A_PERMIT (A_NONE+1)
#define A_DENY (A_PERMIT+1)
struct filter {
struct filterent rule[MAXFILTERS]; /* incoming packet filter */
const char *name;
unsigned fragok : 1;
unsigned logok : 1;
};
/* Which filter set */
#define FL_IN 0
#define FL_OUT 1
#define FL_DIAL 2
#define FL_KEEP 3
struct ipcp;
struct cmdargs;
extern int ParseAddr(struct ipcp *, const char *, struct in_addr *,
struct in_addr *, int *);
extern int filter_Show(struct cmdargs const *);
extern int filter_Set(struct cmdargs const *);
extern const char * filter_Action2Nam(int);
extern const char *filter_Proto2Nam(int);
extern const char *filter_Op2Nam(int);
extern struct in_addr bits2mask(int);
extern void filter_AdjustAddr(struct filter *, struct in_addr *,
struct in_addr *);
|
