filter.h revision 50479 
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 * $FreeBSD: head/usr.sbin/ppp/filter.h 50479 1999-08-28 01:35:59Z peter $
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#ifdef IPPROTO_OSPFIGP
29#define	P_OSPF	4
30#endif
31#define	P_IGMP	5
32
33/* Operations - f_srcop, f_dstop */
34#define	OP_NONE	0
35#define	OP_EQ	1
36#define	OP_GT	2
37#define	OP_LT	3
38
39/* srctype or dsttype */
40#define T_ADDR		0
41#define T_MYADDR	1
42#define T_HISADDR	2
43
44/*
45 * There's a struct filterent for each possible filter rule.  The
46 * layout is designed to minimise size (there are 4 * MAXFILTERS of
47 * them) - which is also conveniently a power of 2 (32 bytes) on
48 * architectures where sizeof(int)==4 (this makes indexing faster).
49 *
50 * f_action and f_proto only need to be 6 and 3 bits, respectively,
51 * but making them 8 bits allows them to be efficently accessed using
52 * byte operations as well as allowing space for future expansion
53 * (expanding MAXFILTERS or converting f_proto IPPROTO_... values).
54 *
55 * Note that there are four free bits in the initial word for future
56 * extensions.
57 */
58struct filterent {
59  unsigned f_action : 8;		/* Filtering action: goto or A_... */
60  unsigned f_proto : 8;		/* Protocol: P_... */
61  unsigned f_srcop : 2;		/* Source port operation: OP_... */
62  unsigned f_dstop : 2;		/* Destination port operation: OP_... */
63  unsigned f_srctype : 2;	/* T_ value of src */
64  unsigned f_dsttype : 2;	/* T_ value of dst */
65  unsigned f_estab : 1;		/* Check TCP ACK bit */
66  unsigned f_syn : 1;		/* Check TCP SYN bit */
67  unsigned f_finrst : 1;	/* Check TCP FIN/RST bits */
68  unsigned f_invert : 1;	/* true to complement match */
69  struct in_range f_src;	/* Source address and mask */
70  struct in_range f_dst;	/* Destination address and mask */
71  u_short f_srcport;		/* Source port, compared with f_srcop */
72  u_short f_dstport;		/* Destination port, compared with f_dstop */
73};
74
75#define	MAXFILTERS	40	/* in each filter set */
76
77/* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */
78#define	A_NONE		(MAXFILTERS)
79#define	A_PERMIT	(A_NONE+1)
80#define	A_DENY		(A_PERMIT+1)
81
82struct filter {
83  struct filterent rule[MAXFILTERS];	/* incoming packet filter */
84  const char *name;
85  unsigned fragok : 1;
86  unsigned logok : 1;
87};
88
89/* Which filter set */
90#define FL_IN		0
91#define FL_OUT		1
92#define FL_DIAL		2
93#define FL_KEEP		3
94
95struct ipcp;
96struct cmdargs;
97
98extern int ParseAddr(struct ipcp *, const char *, struct in_addr *,
99                     struct in_addr *, int *);
100extern int filter_Show(struct cmdargs const *);
101extern int filter_Set(struct cmdargs const *);
102extern const char * filter_Action2Nam(int);
103extern const char *filter_Proto2Nam(int);
104extern const char *filter_Op2Nam(int);
105extern struct in_addr bits2mask(int);
106extern void filter_AdjustAddr(struct filter *, struct in_addr *,
107                              struct in_addr *);
108