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/5.1/sys/netinet/ip_fw.h 115796 2003-06-04 02:19:36Z ticso $
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 metadata) 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 * Note that the code is written so that individual instructions
41 * have a size which is a multiple of 32 bits. This means that, if
42 * such structures contain pointers or other 64-bit entities,
43 * (there is just one instance now) they may end up unaligned on
44 * 64-bit architectures, so the must be handled with care.
45 *
46 * "enum ipfw_opcodes" are the opcodes supported. We can have up
47 * to 256 different opcodes.
48 */
49
50 enum ipfw_opcodes { /* arguments (4 byte each) */
51 O_NOP,
52
53 O_IP_SRC, /* u32 = IP */
54 O_IP_SRC_MASK, /* ip = IP/mask */
55 O_IP_SRC_ME, /* none */
56 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */
57
58 O_IP_DST, /* u32 = IP */
59 O_IP_DST_MASK, /* ip = IP/mask */
60 O_IP_DST_ME, /* none */
61 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */
62
63 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */
64 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */
65 O_PROTO, /* arg1=protocol */
66
67 O_MACADDR2, /* 2 mac addr:mask */
68 O_MAC_TYPE, /* same as srcport */
69
70 O_LAYER2, /* none */
71 O_IN, /* none */
72 O_FRAG, /* none */
73
74 O_RECV, /* none */
75 O_XMIT, /* none */
76 O_VIA, /* none */
77
78 O_IPOPT, /* arg1 = 2*u8 bitmap */
79 O_IPLEN, /* arg1 = len */
80 O_IPID, /* arg1 = id */
81
82 O_IPTOS, /* arg1 = id */
83 O_IPPRECEDENCE, /* arg1 = precedence << 5 */
84 O_IPTTL, /* arg1 = TTL */
85
86 O_IPVER, /* arg1 = version */
87 O_UID, /* u32 = id */
88 O_GID, /* u32 = id */
89 O_ESTAB, /* none (tcp established) */
90 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */
91 O_TCPWIN, /* arg1 = desired win */
92 O_TCPSEQ, /* u32 = desired seq. */
93 O_TCPACK, /* u32 = desired seq. */
94 O_ICMPTYPE, /* u32 = icmp bitmap */
95 O_TCPOPTS, /* arg1 = 2*u8 bitmap */
96
97 O_VERREVPATH, /* none */
98
99 O_PROBE_STATE, /* none */
100 O_KEEP_STATE, /* none */
101 O_LIMIT, /* ipfw_insn_limit */
102 O_LIMIT_PARENT, /* dyn_type, not an opcode. */
103 /*
104 * these are really 'actions', and must be last in the list.
105 */
106
107 O_LOG, /* ipfw_insn_log */
108 O_PROB, /* u32 = match probability */
109
110 O_CHECK_STATE, /* none */
111 O_ACCEPT, /* none */
112 O_DENY, /* none */
113 O_REJECT, /* arg1=icmp arg (same as deny) */
114 O_COUNT, /* none */
115 O_SKIPTO, /* arg1=next rule number */
116 O_PIPE, /* arg1=pipe number */
117 O_QUEUE, /* arg1=queue number */
118 O_DIVERT, /* arg1=port number */
119 O_TEE, /* arg1=port number */
120 O_FORWARD_IP, /* fwd sockaddr */
121 O_FORWARD_MAC, /* fwd mac */
122 O_LAST_OPCODE /* not an opcode! */
123 };
124
125 /*
126 * Template for instructions.
127 *
128 * ipfw_insn is used for all instructions which require no operands,
129 * a single 16-bit value (arg1), or a couple of 8-bit values.
130 *
131 * For other instructions which require different/larger arguments
132 * we have derived structures, ipfw_insn_*.
133 *
134 * The size of the instruction (in 32-bit words) is in the low
135 * 6 bits of "len". The 2 remaining bits are used to implement
136 * NOT and OR on individual instructions. Given a type, you can
137 * compute the length to be put in "len" using F_INSN_SIZE(t)
138 *
139 * F_NOT negates the match result of the instruction.
140 *
141 * F_OR is used to build or blocks. By default, instructions
142 * are evaluated as part of a logical AND. An "or" block
143 * { X or Y or Z } contains F_OR set in all but the last
144 * instruction of the block. A match will cause the code
145 * to skip past the last instruction of the block.
146 *
147 * NOTA BENE: in a couple of places we assume that
148 * sizeof(ipfw_insn) == sizeof(u_int32_t)
149 * this needs to be fixed.
150 *
151 */
152 typedef struct _ipfw_insn { /* template for instructions */
153 enum ipfw_opcodes opcode:8;
154 u_int8_t len; /* numer of 32-byte words */
155 #define F_NOT 0x80
156 #define F_OR 0x40
157 #define F_LEN_MASK 0x3f
158 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
159
160 u_int16_t arg1;
161 } ipfw_insn;
162
163 /*
164 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of
165 * a given type.
166 */
167 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
168
169 /*
170 * This is used to store an array of 16-bit entries (ports etc.)
171 */
172 typedef struct _ipfw_insn_u16 {
173 ipfw_insn o;
174 u_int16_t ports[2]; /* there may be more */
175 } ipfw_insn_u16;
176
177 /*
178 * This is used to store an array of 32-bit entries
179 * (uid, single IPv4 addresses etc.)
180 */
181 typedef struct _ipfw_insn_u32 {
182 ipfw_insn o;
183 u_int32_t d[1]; /* one or more */
184 } ipfw_insn_u32;
185
186 /*
187 * This is used to store IP addr-mask pairs.
188 */
189 typedef struct _ipfw_insn_ip {
190 ipfw_insn o;
191 struct in_addr addr;
192 struct in_addr mask;
193 } ipfw_insn_ip;
194
195 /*
196 * This is used to forward to a given address (ip)
197 */
198 typedef struct _ipfw_insn_sa {
199 ipfw_insn o;
200 struct sockaddr_in sa;
201 } ipfw_insn_sa;
202
203 /*
204 * This is used for MAC addr-mask pairs.
205 */
206 typedef struct _ipfw_insn_mac {
207 ipfw_insn o;
208 u_char addr[12]; /* dst[6] + src[6] */
209 u_char mask[12]; /* dst[6] + src[6] */
210 } ipfw_insn_mac;
211
212 /*
213 * This is used for interface match rules (recv xx, xmit xx)
214 */
215 typedef struct _ipfw_insn_if {
216 ipfw_insn o;
217 union {
218 struct in_addr ip;
219 int32_t unit;
220 } p;
221 char name[IFNAMSIZ];
222 } ipfw_insn_if;
223
224 /*
225 * This is used for pipe and queue actions, which need to store
226 * a single pointer (which can have different size on different
227 * architectures.
228 * Note that, because of previous instructions, pipe_ptr might
229 * be unaligned in the overall structure, so it needs to be
230 * manipulated with care.
231 */
232 typedef struct _ipfw_insn_pipe {
233 ipfw_insn o;
234 void *pipe_ptr; /* XXX */
235 } ipfw_insn_pipe;
236
237 /*
238 * This is used for limit rules.
239 */
240 typedef struct _ipfw_insn_limit {
241 ipfw_insn o;
242 u_int8_t _pad;
243 u_int8_t limit_mask; /* combination of DYN_* below */
244 #define DYN_SRC_ADDR 0x1
245 #define DYN_SRC_PORT 0x2
246 #define DYN_DST_ADDR 0x4
247 #define DYN_DST_PORT 0x8
248
249 u_int16_t conn_limit;
250 } ipfw_insn_limit;
251
252 /*
253 * This is used for log instructions
254 */
255 typedef struct _ipfw_insn_log {
256 ipfw_insn o;
257 u_int32_t max_log; /* how many do we log -- 0 = all */
258 u_int32_t log_left; /* how many left to log */
259 } ipfw_insn_log;
260
261 /*
262 * Here we have the structure representing an ipfw rule.
263 *
264 * It starts with a general area (with link fields and counters)
265 * followed by an array of one or more instructions, which the code
266 * accesses as an array of 32-bit values.
267 *
268 * Given a rule pointer r:
269 *
270 * r->cmd is the start of the first instruction.
271 * ACTION_PTR(r) is the start of the first action (things to do
272 * once a rule matched).
273 *
274 * When assembling instruction, remember the following:
275 *
276 * + if a rule has a "keep-state" (or "limit") option, then the
277 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE
278 * + if a rule has a "log" option, then the first action
279 * (at ACTION_PTR(r)) MUST be O_LOG
280 *
281 * NOTE: we use a simple linked list of rules because we never need
282 * to delete a rule without scanning the list. We do not use
283 * queue(3) macros for portability and readability.
284 */
285
286 struct ip_fw {
287 struct ip_fw *next; /* linked list of rules */
288 struct ip_fw *next_rule; /* ptr to next [skipto] rule */
289 #if 0 /* passed up using 'next_rule' */
290 u_int32_t set_disable; /* disabled sets (for userland) */
291 #endif
292 u_int16_t act_ofs; /* offset of action in 32-bit units */
293 u_int16_t cmd_len; /* # of 32-bit words in cmd */
294 u_int16_t rulenum; /* rule number */
295 u_int8_t set; /* rule set (0..31) */
296 u_int8_t _pad; /* padding */
297
298 /* These fields are present in all rules. */
299 u_int64_t pcnt; /* Packet counter */
300 u_int64_t bcnt; /* Byte counter */
301 u_int32_t timestamp; /* tv_sec of last match */
302
303 ipfw_insn cmd[1]; /* storage for commands */
304 };
305
306 #define ACTION_PTR(rule) \
307 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
308
309 #define RULESIZE(rule) (sizeof(struct ip_fw) + \
310 ((struct ip_fw *)(rule))->cmd_len * 4 - 4)
311
312 /*
313 * This structure is used as a flow mask and a flow id for various
314 * parts of the code.
315 */
316 struct ipfw_flow_id {
317 u_int32_t dst_ip;
318 u_int32_t src_ip;
319 u_int16_t dst_port;
320 u_int16_t src_port;
321 u_int8_t proto;
322 u_int8_t flags; /* protocol-specific flags */
323 };
324
325 /*
326 * dynamic ipfw rule
327 */
328 typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
329
330 struct _ipfw_dyn_rule {
331 ipfw_dyn_rule *next; /* linked list of rules. */
332 struct ip_fw *rule; /* pointer to rule */
333 ipfw_dyn_rule *parent; /* pointer to parent rule */
334 u_int64_t pcnt; /* packet match counter */
335 u_int64_t bcnt; /* byte match counter */
336 struct ipfw_flow_id id; /* (masked) flow id */
337 u_int32_t expire; /* expire time */
338 u_int32_t bucket; /* which bucket in hash table */
339 u_int32_t state; /* state of this rule (typically a
340 * combination of TCP flags)
341 */
342 u_int32_t ack_fwd; /* most recent ACKs in forward */
343 u_int32_t ack_rev; /* and reverse directions (used */
344 /* to generate keepalives) */
345 u_int16_t dyn_type; /* rule type */
346 u_int16_t count; /* refcount */
347 #if 0 /* passed up with 'rule' */
348 u_int16_t rulenum; /* rule number (for userland) */
349 #endif
350 };
351
352 /*
353 * Definitions for IP option names.
354 */
355 #define IP_FW_IPOPT_LSRR 0x01
356 #define IP_FW_IPOPT_SSRR 0x02
357 #define IP_FW_IPOPT_RR 0x04
358 #define IP_FW_IPOPT_TS 0x08
359
360 /*
361 * Definitions for TCP option names.
362 */
363 #define IP_FW_TCPOPT_MSS 0x01
364 #define IP_FW_TCPOPT_WINDOW 0x02
365 #define IP_FW_TCPOPT_SACK 0x04
366 #define IP_FW_TCPOPT_TS 0x08
367 #define IP_FW_TCPOPT_CC 0x10
368
369 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
370
371 /*
372 * Main firewall chains definitions and global var's definitions.
373 */
374 #ifdef _KERNEL
375
376 #define IP_FW_PORT_DYNT_FLAG 0x10000
377 #define IP_FW_PORT_TEE_FLAG 0x20000
378 #define IP_FW_PORT_DENY_FLAG 0x40000
379
380 /*
381 * arguments for calling ipfw_chk() and dummynet_io(). We put them
382 * all into a structure because this way it is easier and more
383 * efficient to pass variables around and extend the interface.
384 */
385 struct ip_fw_args {
386 struct mbuf *m; /* the mbuf chain */
387 struct ifnet *oif; /* output interface */
388 struct sockaddr_in *next_hop; /* forward address */
389 struct ip_fw *rule; /* matching rule */
390 struct ether_header *eh; /* for bridged packets */
391
392 struct route *ro; /* for dummynet */
393 struct sockaddr_in *dst; /* for dummynet */
394 int flags; /* for dummynet */
395
396 struct ipfw_flow_id f_id; /* grabbed from IP header */
397 u_int16_t divert_rule; /* divert cookie */
398 u_int32_t retval;
399 };
400
401 /*
402 * Function definitions.
403 */
404
405 /* Firewall hooks */
406 struct sockopt;
407 struct dn_flow_set;
408
409 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */
410
411 typedef int ip_fw_chk_t (struct ip_fw_args *args);
412 typedef int ip_fw_ctl_t (struct sockopt *);
413 extern ip_fw_chk_t *ip_fw_chk_ptr;
414 extern ip_fw_ctl_t *ip_fw_ctl_ptr;
415 extern int fw_one_pass;
416 extern int fw_enable;
417 #define IPFW_LOADED (ip_fw_chk_ptr != NULL)
418 #endif /* _KERNEL */
419
420 #endif /* _IPFW2_H */
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