FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_fw.h
1 /*
2 * Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD: releng/5.0/sys/netinet/ip_fw.h 105899 2002-10-24 22:32:13Z mux $
26 */
27
28 #ifndef _IPFW2_H
29 #define _IPFW2_H
30 #define IPFW2 1
31 /*
32 * The kernel representation of ipfw rules is made of a list of
33 * 'instructions' (for all practical purposes equivalent to BPF
34 * instructions), which specify which fields of the packet
35 * (or its metatada) should be analysed.
36 *
37 * Each instruction is stored in a structure which begins with
38 * "ipfw_insn", and can contain extra fields depending on the
39 * instruction type (listed below).
40 *
41 * "enum ipfw_opcodes" are the opcodes supported. We can have up
42 * to 256 different opcodes.
43 */
44
45 enum ipfw_opcodes { /* arguments (4 byte each) */
46 O_NOP,
47
48 O_IP_SRC, /* u32 = IP */
49 O_IP_SRC_MASK, /* ip = IP/mask */
50 O_IP_SRC_ME, /* none */
51 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */
52
53 O_IP_DST, /* u32 = IP */
54 O_IP_DST_MASK, /* ip = IP/mask */
55 O_IP_DST_ME, /* none */
56 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */
57
58 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */
59 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */
60 O_PROTO, /* arg1=protocol */
61
62 O_MACADDR2, /* 2 mac addr:mask */
63 O_MAC_TYPE, /* same as srcport */
64
65 O_LAYER2, /* none */
66 O_IN, /* none */
67 O_FRAG, /* none */
68
69 O_RECV, /* none */
70 O_XMIT, /* none */
71 O_VIA, /* none */
72
73 O_IPOPT, /* arg1 = 2*u8 bitmap */
74 O_IPLEN, /* arg1 = len */
75 O_IPID, /* arg1 = id */
76
77 O_IPTOS, /* arg1 = id */
78 O_IPPRECEDENCE, /* arg1 = precedence << 5 */
79 O_IPTTL, /* arg1 = TTL */
80
81 O_IPVER, /* arg1 = version */
82 O_UID, /* u32 = id */
83 O_GID, /* u32 = id */
84 O_ESTAB, /* none (tcp established) */
85 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */
86 O_TCPWIN, /* arg1 = desired win */
87 O_TCPSEQ, /* u32 = desired seq. */
88 O_TCPACK, /* u32 = desired seq. */
89 O_ICMPTYPE, /* u32 = icmp bitmap */
90 O_TCPOPTS, /* arg1 = 2*u8 bitmap */
91
92 O_PROBE_STATE, /* none */
93 O_KEEP_STATE, /* none */
94 O_LIMIT, /* ipfw_insn_limit */
95 O_LIMIT_PARENT, /* dyn_type, not an opcode. */
96 /*
97 * these are really 'actions', and must be last in the list.
98 */
99
100 O_LOG, /* ipfw_insn_log */
101 O_PROB, /* u32 = match probability */
102
103 O_CHECK_STATE, /* none */
104 O_ACCEPT, /* none */
105 O_DENY, /* none */
106 O_REJECT, /* arg1=icmp arg (same as deny) */
107 O_COUNT, /* none */
108 O_SKIPTO, /* arg1=next rule number */
109 O_PIPE, /* arg1=pipe number */
110 O_QUEUE, /* arg1=queue number */
111 O_DIVERT, /* arg1=port number */
112 O_TEE, /* arg1=port number */
113 O_FORWARD_IP, /* fwd sockaddr */
114 O_FORWARD_MAC, /* fwd mac */
115 O_LAST_OPCODE /* not an opcode! */
116 };
117
118 /*
119 * Template for instructions.
120 *
121 * ipfw_insn is used for all instructions which require no operands,
122 * a single 16-bit value (arg1), or a couple of 8-bit values.
123 *
124 * For other instructions which require different/larger arguments
125 * we have derived structures, ipfw_insn_*.
126 *
127 * The size of the instruction (in 32-bit words) is in the low
128 * 6 bits of "len". The 2 remaining bits are used to implement
129 * NOT and OR on individual instructions. Given a type, you can
130 * compute the length to be put in "len" using F_INSN_SIZE(t)
131 *
132 * F_NOT negates the match result of the instruction.
133 *
134 * F_OR is used to build or blocks. By default, instructions
135 * are evaluated as part of a logical AND. An "or" block
136 * { X or Y or Z } contains F_OR set in all but the last
137 * instruction of the block. A match will cause the code
138 * to skip past the last instruction of the block.
139 *
140 * NOTA BENE: in a couple of places we assume that
141 * sizeof(ipfw_insn) == sizeof(u_int32_t)
142 * this needs to be fixed.
143 *
144 */
145 typedef struct _ipfw_insn { /* template for instructions */
146 enum ipfw_opcodes opcode:8;
147 u_int8_t len; /* numer of 32-byte words */
148 #define F_NOT 0x80
149 #define F_OR 0x40
150 #define F_LEN_MASK 0x3f
151 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
152
153 u_int16_t arg1;
154 } ipfw_insn;
155
156 /*
157 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of
158 * a given type.
159 */
160 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
161
162 /*
163 * This is used to store an array of 16-bit entries (ports etc.)
164 */
165 typedef struct _ipfw_insn_u16 {
166 ipfw_insn o;
167 u_int16_t ports[2]; /* there may be more */
168 } ipfw_insn_u16;
169
170 /*
171 * This is used to store an array of 32-bit entries
172 * (uid, single IPv4 addresses etc.)
173 */
174 typedef struct _ipfw_insn_u32 {
175 ipfw_insn o;
176 u_int32_t d[1]; /* one or more */
177 } ipfw_insn_u32;
178
179 /*
180 * This is used to store IP addr-mask pairs.
181 */
182 typedef struct _ipfw_insn_ip {
183 ipfw_insn o;
184 struct in_addr addr;
185 struct in_addr mask;
186 } ipfw_insn_ip;
187
188 /*
189 * This is used to forward to a given address (ip)
190 */
191 typedef struct _ipfw_insn_sa {
192 ipfw_insn o;
193 struct sockaddr_in sa;
194 } ipfw_insn_sa;
195
196 /*
197 * This is used for MAC addr-mask pairs.
198 */
199 typedef struct _ipfw_insn_mac {
200 ipfw_insn o;
201 u_char addr[12]; /* dst[6] + src[6] */
202 u_char mask[12]; /* dst[6] + src[6] */
203 } ipfw_insn_mac;
204
205 /*
206 * This is used for interface match rules (recv xx, xmit xx)
207 */
208 typedef struct _ipfw_insn_if {
209 ipfw_insn o;
210 union {
211 struct in_addr ip;
212 int unit;
213 } p;
214 char name[IFNAMSIZ];
215 } ipfw_insn_if;
216
217 /*
218 * This is used for pipe and queue actions, which need to store
219 * a single pointer (which can have different size on different
220 * architectures.
221 */
222 typedef struct _ipfw_insn_pipe {
223 ipfw_insn o;
224 void *pipe_ptr;
225 } ipfw_insn_pipe;
226
227 /*
228 * This is used for limit rules.
229 */
230 typedef struct _ipfw_insn_limit {
231 ipfw_insn o;
232 u_int8_t _pad;
233 u_int8_t limit_mask; /* combination of DYN_* below */
234 #define DYN_SRC_ADDR 0x1
235 #define DYN_SRC_PORT 0x2
236 #define DYN_DST_ADDR 0x4
237 #define DYN_DST_PORT 0x8
238
239 u_int16_t conn_limit;
240 } ipfw_insn_limit;
241
242 /*
243 * This is used for log instructions
244 */
245 typedef struct _ipfw_insn_log {
246 ipfw_insn o;
247 u_int32_t max_log; /* how many do we log -- 0 = all */
248 u_int32_t log_left; /* how many left to log */
249 } ipfw_insn_log;
250
251 /*
252 * Here we have the structure representing an ipfw rule.
253 *
254 * It starts with a general area (with link fields and counters)
255 * followed by an array of one or more instructions, which the code
256 * accesses as an array of 32-bit values.
257 *
258 * Given a rule pointer r:
259 *
260 * r->cmd is the start of the first instruction.
261 * ACTION_PTR(r) is the start of the first action (things to do
262 * once a rule matched).
263 *
264 * When assembling instruction, remember the following:
265 *
266 * + if a rule has a "keep-state" (or "limit") option, then the
267 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE
268 * + if a rule has a "log" option, then the first action
269 * (at ACTION_PTR(r)) MUST be O_LOG
270 *
271 * NOTE: we use a simple linked list of rules because we never need
272 * to delete a rule without scanning the list. We do not use
273 * queue(3) macros for portability and readability.
274 */
275
276 struct ip_fw {
277 struct ip_fw *next; /* linked list of rules */
278 struct ip_fw *next_rule; /* ptr to next [skipto] rule */
279 u_int32_t set_disable; /* disabled sets (for userland) */
280 u_int16_t act_ofs; /* offset of action in 32-bit units */
281 u_int16_t cmd_len; /* # of 32-bit words in cmd */
282 u_int16_t rulenum; /* rule number */
283 u_int8_t set; /* rule set (0..31) */
284 u_int8_t _pad; /* padding */
285
286 /* These fields are present in all rules. */
287 u_int64_t pcnt; /* Packet counter */
288 u_int64_t bcnt; /* Byte counter */
289 u_int32_t timestamp; /* tv_sec of last match */
290
291 ipfw_insn cmd[1]; /* storage for commands */
292 };
293
294 #define ACTION_PTR(rule) \
295 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
296
297 #define RULESIZE(rule) (sizeof(struct ip_fw) + \
298 ((struct ip_fw *)(rule))->cmd_len * 4 - 4)
299
300 /*
301 * This structure is used as a flow mask and a flow id for various
302 * parts of the code.
303 */
304 struct ipfw_flow_id {
305 u_int32_t dst_ip;
306 u_int32_t src_ip;
307 u_int16_t dst_port;
308 u_int16_t src_port;
309 u_int8_t proto;
310 u_int8_t flags; /* protocol-specific flags */
311 };
312
313 /*
314 * dynamic ipfw rule
315 */
316 typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
317
318 struct _ipfw_dyn_rule {
319 ipfw_dyn_rule *next; /* linked list of rules. */
320 struct ipfw_flow_id id; /* (masked) flow id */
321 struct ip_fw *rule; /* pointer to rule */
322 ipfw_dyn_rule *parent; /* pointer to parent rule */
323 u_int32_t expire; /* expire time */
324 u_int64_t pcnt; /* packet match counter */
325 u_int64_t bcnt; /* byte match counter */
326 u_int32_t bucket; /* which bucket in hash table */
327 u_int32_t state; /* state of this rule (typically a
328 * combination of TCP flags)
329 */
330 u_int32_t ack_fwd; /* most recent ACKs in forward */
331 u_int32_t ack_rev; /* and reverse directions (used */
332 /* to generate keepalives) */
333 u_int16_t dyn_type; /* rule type */
334 u_int16_t count; /* refcount */
335 u_int16_t rulenum; /* rule number (for userland) */
336 };
337
338 /*
339 * Definitions for IP option names.
340 */
341 #define IP_FW_IPOPT_LSRR 0x01
342 #define IP_FW_IPOPT_SSRR 0x02
343 #define IP_FW_IPOPT_RR 0x04
344 #define IP_FW_IPOPT_TS 0x08
345
346 /*
347 * Definitions for TCP option names.
348 */
349 #define IP_FW_TCPOPT_MSS 0x01
350 #define IP_FW_TCPOPT_WINDOW 0x02
351 #define IP_FW_TCPOPT_SACK 0x04
352 #define IP_FW_TCPOPT_TS 0x08
353 #define IP_FW_TCPOPT_CC 0x10
354
355 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
356
357 /*
358 * Main firewall chains definitions and global var's definitions.
359 */
360 #ifdef _KERNEL
361
362 #define IP_FW_PORT_DYNT_FLAG 0x10000
363 #define IP_FW_PORT_TEE_FLAG 0x20000
364 #define IP_FW_PORT_DENY_FLAG 0x40000
365
366 /*
367 * arguments for calling ipfw_chk() and dummynet_io(). We put them
368 * all into a structure because this way it is easier and more
369 * efficient to pass variables around and extend the interface.
370 */
371 struct ip_fw_args {
372 struct mbuf *m; /* the mbuf chain */
373 struct ifnet *oif; /* output interface */
374 struct sockaddr_in *next_hop; /* forward address */
375 struct ip_fw *rule; /* matching rule */
376 struct ether_header *eh; /* for bridged packets */
377
378 struct route *ro; /* for dummynet */
379 struct sockaddr_in *dst; /* for dummynet */
380 int flags; /* for dummynet */
381
382 struct ipfw_flow_id f_id; /* grabbed from IP header */
383 u_int16_t divert_rule; /* divert cookie */
384 u_int32_t retval;
385 };
386
387 /*
388 * Function definitions.
389 */
390
391 /* Firewall hooks */
392 struct sockopt;
393 struct dn_flow_set;
394
395 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */
396
397 typedef int ip_fw_chk_t (struct ip_fw_args *args);
398 typedef int ip_fw_ctl_t (struct sockopt *);
399 extern ip_fw_chk_t *ip_fw_chk_ptr;
400 extern ip_fw_ctl_t *ip_fw_ctl_ptr;
401 extern int fw_one_pass;
402 extern int fw_enable;
403 #define IPFW_LOADED (ip_fw_chk_ptr != NULL)
404 #endif /* _KERNEL */
405
406 #endif /* _IPFW2_H */
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