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/5.2/sys/netinet/ip_fw.h 121816 2003-10-31 18:32:15Z brooks $
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 /*
105 * These are really 'actions'.
106 */
107
108 O_LOG, /* ipfw_insn_log */
109 O_PROB, /* u32 = match probability */
110
111 O_CHECK_STATE, /* none */
112 O_ACCEPT, /* none */
113 O_DENY, /* none */
114 O_REJECT, /* arg1=icmp arg (same as deny) */
115 O_COUNT, /* none */
116 O_SKIPTO, /* arg1=next rule number */
117 O_PIPE, /* arg1=pipe number */
118 O_QUEUE, /* arg1=queue number */
119 O_DIVERT, /* arg1=port number */
120 O_TEE, /* arg1=port number */
121 O_FORWARD_IP, /* fwd sockaddr */
122 O_FORWARD_MAC, /* fwd mac */
123
124 /*
125 * More opcodes.
126 */
127 O_IPSEC, /* has ipsec history */
128
129 O_LAST_OPCODE /* not an opcode! */
130 };
131
132 /*
133 * Template for instructions.
134 *
135 * ipfw_insn is used for all instructions which require no operands,
136 * a single 16-bit value (arg1), or a couple of 8-bit values.
137 *
138 * For other instructions which require different/larger arguments
139 * we have derived structures, ipfw_insn_*.
140 *
141 * The size of the instruction (in 32-bit words) is in the low
142 * 6 bits of "len". The 2 remaining bits are used to implement
143 * NOT and OR on individual instructions. Given a type, you can
144 * compute the length to be put in "len" using F_INSN_SIZE(t)
145 *
146 * F_NOT negates the match result of the instruction.
147 *
148 * F_OR is used to build or blocks. By default, instructions
149 * are evaluated as part of a logical AND. An "or" block
150 * { X or Y or Z } contains F_OR set in all but the last
151 * instruction of the block. A match will cause the code
152 * to skip past the last instruction of the block.
153 *
154 * NOTA BENE: in a couple of places we assume that
155 * sizeof(ipfw_insn) == sizeof(u_int32_t)
156 * this needs to be fixed.
157 *
158 */
159 typedef struct _ipfw_insn { /* template for instructions */
160 enum ipfw_opcodes opcode:8;
161 u_int8_t len; /* numer of 32-byte words */
162 #define F_NOT 0x80
163 #define F_OR 0x40
164 #define F_LEN_MASK 0x3f
165 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
166
167 u_int16_t arg1;
168 } ipfw_insn;
169
170 /*
171 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of
172 * a given type.
173 */
174 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
175
176 /*
177 * This is used to store an array of 16-bit entries (ports etc.)
178 */
179 typedef struct _ipfw_insn_u16 {
180 ipfw_insn o;
181 u_int16_t ports[2]; /* there may be more */
182 } ipfw_insn_u16;
183
184 /*
185 * This is used to store an array of 32-bit entries
186 * (uid, single IPv4 addresses etc.)
187 */
188 typedef struct _ipfw_insn_u32 {
189 ipfw_insn o;
190 u_int32_t d[1]; /* one or more */
191 } ipfw_insn_u32;
192
193 /*
194 * This is used to store IP addr-mask pairs.
195 */
196 typedef struct _ipfw_insn_ip {
197 ipfw_insn o;
198 struct in_addr addr;
199 struct in_addr mask;
200 } ipfw_insn_ip;
201
202 /*
203 * This is used to forward to a given address (ip).
204 */
205 typedef struct _ipfw_insn_sa {
206 ipfw_insn o;
207 struct sockaddr_in sa;
208 } ipfw_insn_sa;
209
210 /*
211 * This is used for MAC addr-mask pairs.
212 */
213 typedef struct _ipfw_insn_mac {
214 ipfw_insn o;
215 u_char addr[12]; /* dst[6] + src[6] */
216 u_char mask[12]; /* dst[6] + src[6] */
217 } ipfw_insn_mac;
218
219 /*
220 * This is used for interface match rules (recv xx, xmit xx).
221 */
222 typedef struct _ipfw_insn_if {
223 ipfw_insn o;
224 union {
225 struct in_addr ip;
226 int glob;
227 } p;
228 char name[IFNAMSIZ];
229 } ipfw_insn_if;
230
231 /*
232 * This is used for pipe and queue actions, which need to store
233 * a single pointer (which can have different size on different
234 * architectures.
235 * Note that, because of previous instructions, pipe_ptr might
236 * be unaligned in the overall structure, so it needs to be
237 * manipulated with care.
238 */
239 typedef struct _ipfw_insn_pipe {
240 ipfw_insn o;
241 void *pipe_ptr; /* XXX */
242 } ipfw_insn_pipe;
243
244 /*
245 * This is used for limit rules.
246 */
247 typedef struct _ipfw_insn_limit {
248 ipfw_insn o;
249 u_int8_t _pad;
250 u_int8_t limit_mask; /* combination of DYN_* below */
251 #define DYN_SRC_ADDR 0x1
252 #define DYN_SRC_PORT 0x2
253 #define DYN_DST_ADDR 0x4
254 #define DYN_DST_PORT 0x8
255
256 u_int16_t conn_limit;
257 } ipfw_insn_limit;
258
259 /*
260 * This is used for log instructions.
261 */
262 typedef struct _ipfw_insn_log {
263 ipfw_insn o;
264 u_int32_t max_log; /* how many do we log -- 0 = all */
265 u_int32_t log_left; /* how many left to log */
266 } ipfw_insn_log;
267
268 /*
269 * Here we have the structure representing an ipfw rule.
270 *
271 * It starts with a general area (with link fields and counters)
272 * followed by an array of one or more instructions, which the code
273 * accesses as an array of 32-bit values.
274 *
275 * Given a rule pointer r:
276 *
277 * r->cmd is the start of the first instruction.
278 * ACTION_PTR(r) is the start of the first action (things to do
279 * once a rule matched).
280 *
281 * When assembling instruction, remember the following:
282 *
283 * + if a rule has a "keep-state" (or "limit") option, then the
284 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE
285 * + if a rule has a "log" option, then the first action
286 * (at ACTION_PTR(r)) MUST be O_LOG
287 *
288 * NOTE: we use a simple linked list of rules because we never need
289 * to delete a rule without scanning the list. We do not use
290 * queue(3) macros for portability and readability.
291 */
292
293 struct ip_fw {
294 struct ip_fw *next; /* linked list of rules */
295 struct ip_fw *next_rule; /* ptr to next [skipto] rule */
296 /* 'next_rule' is used to pass up 'set_disable' status */
297
298 u_int16_t act_ofs; /* offset of action in 32-bit units */
299 u_int16_t cmd_len; /* # of 32-bit words in cmd */
300 u_int16_t rulenum; /* rule number */
301 u_int8_t set; /* rule set (0..31) */
302 #define RESVD_SET 31 /* set for default and persistent rules */
303 u_int8_t _pad; /* padding */
304
305 /* These fields are present in all rules. */
306 u_int64_t pcnt; /* Packet counter */
307 u_int64_t bcnt; /* Byte counter */
308 u_int32_t timestamp; /* tv_sec of last match */
309
310 ipfw_insn cmd[1]; /* storage for commands */
311 };
312
313 #define ACTION_PTR(rule) \
314 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
315
316 #define RULESIZE(rule) (sizeof(struct ip_fw) + \
317 ((struct ip_fw *)(rule))->cmd_len * 4 - 4)
318
319 /*
320 * This structure is used as a flow mask and a flow id for various
321 * parts of the code.
322 */
323 struct ipfw_flow_id {
324 u_int32_t dst_ip;
325 u_int32_t src_ip;
326 u_int16_t dst_port;
327 u_int16_t src_port;
328 u_int8_t proto;
329 u_int8_t flags; /* protocol-specific flags */
330 };
331
332 /*
333 * Dynamic ipfw rule.
334 */
335 typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
336
337 struct _ipfw_dyn_rule {
338 ipfw_dyn_rule *next; /* linked list of rules. */
339 struct ip_fw *rule; /* pointer to rule */
340 /* 'rule' is used to pass up the rule number (from the parent) */
341
342 ipfw_dyn_rule *parent; /* pointer to parent rule */
343 u_int64_t pcnt; /* packet match counter */
344 u_int64_t bcnt; /* byte match counter */
345 struct ipfw_flow_id id; /* (masked) flow id */
346 u_int32_t expire; /* expire time */
347 u_int32_t bucket; /* which bucket in hash table */
348 u_int32_t state; /* state of this rule (typically a
349 * combination of TCP flags)
350 */
351 u_int32_t ack_fwd; /* most recent ACKs in forward */
352 u_int32_t ack_rev; /* and reverse directions (used */
353 /* to generate keepalives) */
354 u_int16_t dyn_type; /* rule type */
355 u_int16_t count; /* refcount */
356 };
357
358 /*
359 * Definitions for IP option names.
360 */
361 #define IP_FW_IPOPT_LSRR 0x01
362 #define IP_FW_IPOPT_SSRR 0x02
363 #define IP_FW_IPOPT_RR 0x04
364 #define IP_FW_IPOPT_TS 0x08
365
366 /*
367 * Definitions for TCP option names.
368 */
369 #define IP_FW_TCPOPT_MSS 0x01
370 #define IP_FW_TCPOPT_WINDOW 0x02
371 #define IP_FW_TCPOPT_SACK 0x04
372 #define IP_FW_TCPOPT_TS 0x08
373 #define IP_FW_TCPOPT_CC 0x10
374
375 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
376
377 /*
378 * Main firewall chains definitions and global var's definitions.
379 */
380 #ifdef _KERNEL
381
382 #define IP_FW_PORT_DYNT_FLAG 0x10000
383 #define IP_FW_PORT_TEE_FLAG 0x20000
384 #define IP_FW_PORT_DENY_FLAG 0x40000
385
386 /*
387 * Arguments for calling ipfw_chk() and dummynet_io(). We put them
388 * all into a structure because this way it is easier and more
389 * efficient to pass variables around and extend the interface.
390 */
391 struct ip_fw_args {
392 struct mbuf *m; /* the mbuf chain */
393 struct ifnet *oif; /* output interface */
394 struct sockaddr_in *next_hop; /* forward address */
395 struct ip_fw *rule; /* matching rule */
396 struct ether_header *eh; /* for bridged packets */
397
398 struct route *ro; /* for dummynet */
399 struct sockaddr_in *dst; /* for dummynet */
400 int flags; /* for dummynet */
401
402 struct ipfw_flow_id f_id; /* grabbed from IP header */
403 u_int16_t divert_rule; /* divert cookie */
404 u_int32_t retval;
405 };
406
407 /*
408 * Function definitions.
409 */
410
411 /* Firewall hooks */
412 struct sockopt;
413 struct dn_flow_set;
414
415 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */
416
417 typedef int ip_fw_chk_t (struct ip_fw_args *args);
418 typedef int ip_fw_ctl_t (struct sockopt *);
419 extern ip_fw_chk_t *ip_fw_chk_ptr;
420 extern ip_fw_ctl_t *ip_fw_ctl_ptr;
421 extern int fw_one_pass;
422 extern int fw_enable;
423 #define IPFW_LOADED (ip_fw_chk_ptr != NULL)
424 #endif /* _KERNEL */
425
426 #endif /* _IPFW2_H */
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