filter.h revision 49372 
1/*
2 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
3 *
4 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
5 *
6 * Redistribution and use in source and binary forms are permitted
7 * provided that the above copyright notice and this paragraph are
8 * duplicated in all such forms and that any documentation,
9 * advertising materials, and other materials related to such
10 * distribution and use acknowledge that the software was developed
11 * by the Internet Initiative Japan.  The name of the
12 * IIJ may not be used to endorse or promote products derived
13 * from this software without specific prior written permission.
14 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
16 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
17 *
18 * $Id: filter.h,v 1.17 1999/07/27 23:43:59 brian Exp $
19 *
20 *	TODO:
21 */
22
23/* Known protocols - f_proto */
24#define	P_NONE	0
25#define	P_TCP	1
26#define	P_UDP	2
27#define	P_ICMP	3
28#define	P_OSPF	4
29#define	P_IGMP	5
30
31/* Operations - f_srcop, f_dstop */
32#define	OP_NONE	0
33#define	OP_EQ	1
34#define	OP_GT	2
35#define	OP_LT	3
36
37/* srctype or dsttype */
38#define T_ADDR		0
39#define T_MYADDR	1
40#define T_HISADDR	2
41
42/*
43 * There's a struct filterent for each possible filter rule.  The
44 * layout is designed to minimise size (there are 4 * MAXFILTERS of
45 * them) - which is also conveniently a power of 2 (32 bytes) on
46 * architectures where sizeof(int)==4 (this makes indexing faster).
47 *
48 * f_action and f_proto only need to be 6 and 3 bits, respectively,
49 * but making them 8 bits allows them to be efficently accessed using
50 * byte operations as well as allowing space for future expansion
51 * (expanding MAXFILTERS or converting f_proto IPPROTO_... values).
52 *
53 * Note that there are four free bits in the initial word for future
54 * extensions.
55 */
56struct filterent {
57  unsigned f_action : 8;		/* Filtering action: goto or A_... */
58  unsigned f_proto : 8;		/* Protocol: P_... */
59  unsigned f_srcop : 2;		/* Source port operation: OP_... */
60  unsigned f_dstop : 2;		/* Destination port operation: OP_... */
61  unsigned f_srctype : 2;	/* T_ value of src */
62  unsigned f_dsttype : 2;	/* T_ value of dst */
63  unsigned f_estab : 1;		/* Check TCP ACK bit */
64  unsigned f_syn : 1;		/* Check TCP SYN bit */
65  unsigned f_finrst : 1;	/* Check TCP FIN/RST bits */
66  unsigned f_invert : 1;	/* true to complement match */
67  struct in_range f_src;	/* Source address and mask */
68  struct in_range f_dst;	/* Destination address and mask */
69  u_short f_srcport;		/* Source port, compared with f_srcop */
70  u_short f_dstport;		/* Destination port, compared with f_dstop */
71};
72
73#define	MAXFILTERS	40	/* in each filter set */
74
75/* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */
76#define	A_NONE		(MAXFILTERS)
77#define	A_PERMIT	(A_NONE+1)
78#define	A_DENY		(A_PERMIT+1)
79
80struct filter {
81  struct filterent rule[MAXFILTERS];	/* incoming packet filter */
82  const char *name;
83  unsigned fragok : 1;
84  unsigned logok : 1;
85};
86
87/* Which filter set */
88#define FL_IN		0
89#define FL_OUT		1
90#define FL_DIAL		2
91#define FL_KEEP		3
92
93struct ipcp;
94struct cmdargs;
95
96extern int ParseAddr(struct ipcp *, const char *, struct in_addr *,
97                     struct in_addr *, int *);
98extern int filter_Show(struct cmdargs const *);
99extern int filter_Set(struct cmdargs const *);
100extern const char * filter_Action2Nam(int);
101extern const char *filter_Proto2Nam(int);
102extern const char *filter_Op2Nam(int);
103extern struct in_addr bits2mask(int);
104extern void filter_AdjustAddr(struct filter *, struct in_addr *,
105                              struct in_addr *);
106