ip_fw.h revision 27981 
1/*
2 * Copyright (c) 1993 Daniel Boulet
3 * Copyright (c) 1994 Ugen J.S.Antsilevich
4 *
5 * Redistribution and use in source forms, with and without modification,
6 * are permitted provided that this entire comment appears intact.
7 *
8 * Redistribution in binary form may occur without any restrictions.
9 * Obviously, it would be nice if you gave credit where credit is due
10 * but requiring it would be too onerous.
11 *
12 * This software is provided ``AS IS'' without any warranties of any kind.
13 *
14 *	$Id: ip_fw.h,v 1.27 1997/06/02 05:02:36 julian Exp $
15 */
16
17#ifndef _IP_FW_H
18#define _IP_FW_H
19
20#include <net/if.h>
21
22/*
23 * This union structure identifies an interface, either explicitly
24 * by name or implicitly by IP address. The flags IP_FW_F_IIFNAME
25 * and IP_FW_F_OIFNAME say how to interpret this structure. An
26 * interface unit number of -1 matches any unit number, while an
27 * IP address of 0.0.0.0 indicates matches any interface.
28 *
29 * The receive and transmit interfaces are only compared against the
30 * the packet if the corresponding bit (IP_FW_F_IIFACE or IP_FW_F_OIFACE)
31 * is set. Note some packets lack a receive or transmit interface
32 * (in which case the missing "interface" never matches).
33 */
34
35union ip_fw_if {
36    struct in_addr fu_via_ip;	/* Specified by IP address */
37    struct {			/* Specified by interface name */
38#define FW_IFNLEN     IFNAMSIZ
39	    char  name[FW_IFNLEN];
40	    short unit;		/* -1 means match any unit */
41    } fu_via_if;
42};
43
44/*
45 * Format of an IP firewall descriptor
46 *
47 * fw_src, fw_dst, fw_smsk, fw_dmsk are always stored in network byte order.
48 * fw_flg and fw_n*p are stored in host byte order (of course).
49 * Port numbers are stored in HOST byte order.
50 * Warning: setsockopt() will fail if sizeof(struct ip_fw) > MLEN (108)
51 */
52
53struct ip_fw {
54    u_long fw_pcnt,fw_bcnt;		/* Packet and byte counters */
55    struct in_addr fw_src, fw_dst;	/* Source and destination IP addr */
56    struct in_addr fw_smsk, fw_dmsk;	/* Mask for src and dest IP addr */
57    u_short fw_number;			/* Rule number */
58    u_short fw_flg;			/* Flags word */
59#define IP_FW_MAX_PORTS	10		/* A reasonable maximum */
60    u_short fw_pts[IP_FW_MAX_PORTS];	/* Array of port numbers to match */
61    u_char fw_ipopt,fw_ipnopt;		/* IP options set/unset */
62    u_char fw_tcpf,fw_tcpnf;		/* TCP flags set/unset */
63#define IP_FW_ICMPTYPES_DIM (32 / (sizeof(unsigned) * 8))
64    unsigned fw_icmptypes[IP_FW_ICMPTYPES_DIM]; /* ICMP types bitmap */
65    long timestamp;			/* timestamp (tv_sec) of last match */
66    union ip_fw_if fw_in_if, fw_out_if;	/* Incoming and outgoing interfaces */
67    union {
68	u_short fu_divert_port;		/* Divert/tee port (options IPDIVERT) */
69	u_short fu_skipto_rule;		/* SKIPTO command rule number */
70	u_short fu_reject_code;		/* REJECT response code */
71    } fw_un;
72    u_char fw_prot;			/* IP protocol */
73    u_char fw_nports;			/* N'of src ports and # of dst ports */
74					/* in ports array (dst ports follow */
75					/* src ports; max of 10 ports in all; */
76					/* count of 0 means match all ports) */
77};
78
79#define IP_FW_GETNSRCP(rule)		((rule)->fw_nports & 0x0f)
80#define IP_FW_SETNSRCP(rule, n)		do {				\
81					  (rule)->fw_nports &= ~0x0f;	\
82					  (rule)->fw_nports |= (n);	\
83					} while (0)
84#define IP_FW_GETNDSTP(rule)		((rule)->fw_nports >> 4)
85#define IP_FW_SETNDSTP(rule, n)		do {				\
86					  (rule)->fw_nports &= ~0xf0;	\
87					  (rule)->fw_nports |= (n) << 4;\
88					} while (0)
89
90#define fw_divert_port	fw_un.fu_divert_port
91#define fw_skipto_rule	fw_un.fu_skipto_rule
92#define fw_reject_code	fw_un.fu_reject_code
93
94struct ip_fw_chain {
95        LIST_ENTRY(ip_fw_chain) chain;
96        struct ip_fw    *rule;
97};
98
99/*
100 * Values for "flags" field .
101 */
102#define IP_FW_F_IN	0x0001	/* Check inbound packets		*/
103#define IP_FW_F_OUT	0x0002	/* Check outbound packets		*/
104#define IP_FW_F_IIFACE	0x0004	/* Apply inbound interface test		*/
105#define IP_FW_F_OIFACE	0x0008	/* Apply outbound interface test	*/
106
107#define IP_FW_F_COMMAND 0x0070	/* Mask for type of chain entry:	*/
108#define IP_FW_F_DENY	0x0000	/* This is a deny rule			*/
109#define IP_FW_F_REJECT	0x0010	/* Deny and send a response packet	*/
110#define IP_FW_F_ACCEPT	0x0020	/* This is an accept rule		*/
111#define IP_FW_F_COUNT	0x0030	/* This is a count rule			*/
112#define IP_FW_F_DIVERT	0x0040	/* This is a divert rule		*/
113#define IP_FW_F_TEE	0x0050	/* This is a tee rule			*/
114#define IP_FW_F_SKIPTO	0x0060	/* This is a skipto rule		*/
115
116#define IP_FW_F_PRN	0x0080	/* Print if this rule matches		*/
117
118#define IP_FW_F_SRNG	0x0100	/* The first two src ports are a min	*
119				 * and max range (stored in host byte	*
120				 * order).				*/
121
122#define IP_FW_F_DRNG	0x0200	/* The first two dst ports are a min	*
123				 * and max range (stored in host byte	*
124				 * order).				*/
125
126#define IP_FW_F_IIFNAME	0x0400	/* In interface by name/unit (not IP)	*/
127#define IP_FW_F_OIFNAME	0x0800	/* Out interface by name/unit (not IP)	*/
128
129#define IP_FW_F_INVSRC	0x1000	/* Invert sense of src check		*/
130#define IP_FW_F_INVDST	0x2000	/* Invert sense of dst check		*/
131
132#define IP_FW_F_FRAG	0x4000	/* Fragment				*/
133
134#define IP_FW_F_ICMPBIT 0x8000	/* ICMP type bitmap is valid		*/
135
136#define IP_FW_F_MASK	0xFFFF	/* All possible flag bits mask		*/
137
138/*
139 * For backwards compatibility with rules specifying "via iface" but
140 * not restricted to only "in" or "out" packets, we define this combination
141 * of bits to represent this configuration.
142 */
143
144#define IF_FW_F_VIAHACK	(IP_FW_F_IN|IP_FW_F_OUT|IP_FW_F_IIFACE|IP_FW_F_OIFACE)
145
146/*
147 * Definitions for REJECT response codes.
148 * Values less than 256 correspond to ICMP unreachable codes.
149 */
150#define IP_FW_REJECT_RST	0x0100		/* TCP packets: send RST */
151
152/*
153 * Definitions for IP option names.
154 */
155#define IP_FW_IPOPT_LSRR	0x01
156#define IP_FW_IPOPT_SSRR	0x02
157#define IP_FW_IPOPT_RR		0x04
158#define IP_FW_IPOPT_TS		0x08
159
160/*
161 * Definitions for TCP flags.
162 */
163#define IP_FW_TCPF_FIN		TH_FIN
164#define IP_FW_TCPF_SYN		TH_SYN
165#define IP_FW_TCPF_RST		TH_RST
166#define IP_FW_TCPF_PSH		TH_PUSH
167#define IP_FW_TCPF_ACK		TH_ACK
168#define IP_FW_TCPF_URG		TH_URG
169#define IP_FW_TCPF_ESTAB	0x40
170
171/*
172 * Main firewall chains definitions and global var's definitions.
173 */
174#ifdef KERNEL
175
176/*
177 * Function definitions.
178 */
179void ip_fw_init(void);
180
181#endif /* KERNEL */
182
183#endif /* _IP_FW_H */
184