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 * $FreeBSD$
26 */
27
28 #ifndef _IPFW2_H
29 #define _IPFW2_H
30 #define IPFW2 1
31
32 /*
33 * The kernel representation of ipfw rules is made of a list of
34 * 'instructions' (for all practical purposes equivalent to BPF
35 * instructions), which specify which fields of the packet
36 * (or its metadata) should be analysed.
37 *
38 * Each instruction is stored in a structure which begins with
39 * "ipfw_insn", and can contain extra fields depending on the
40 * instruction type (listed below).
41 * Note that the code is written so that individual instructions
42 * have a size which is a multiple of 32 bits. This means that, if
43 * such structures contain pointers or other 64-bit entities,
44 * (there is just one instance now) they may end up unaligned on
45 * 64-bit architectures, so the must be handled with care.
46 *
47 * "enum ipfw_opcodes" are the opcodes supported. We can have up
48 * to 256 different opcodes. When adding new opcodes, they should
49 * be appended to the end of the opcode list before O_LAST_OPCODE,
50 * this will prevent the ABI from being broken, otherwise users
51 * will have to recompile ipfw(8) when they update the kernel.
52 */
53
54 enum ipfw_opcodes { /* arguments (4 byte each) */
55 O_NOP,
56
57 O_IP_SRC, /* u32 = IP */
58 O_IP_SRC_MASK, /* ip = IP/mask */
59 O_IP_SRC_ME, /* none */
60 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */
61
62 O_IP_DST, /* u32 = IP */
63 O_IP_DST_MASK, /* ip = IP/mask */
64 O_IP_DST_ME, /* none */
65 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */
66
67 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */
68 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */
69 O_PROTO, /* arg1=protocol */
70
71 O_MACADDR2, /* 2 mac addr:mask */
72 O_MAC_TYPE, /* same as srcport */
73
74 O_LAYER2, /* none */
75 O_IN, /* none */
76 O_FRAG, /* none */
77
78 O_RECV, /* none */
79 O_XMIT, /* none */
80 O_VIA, /* none */
81
82 O_IPOPT, /* arg1 = 2*u8 bitmap */
83 O_IPLEN, /* arg1 = len */
84 O_IPID, /* arg1 = id */
85
86 O_IPTOS, /* arg1 = id */
87 O_IPPRECEDENCE, /* arg1 = precedence << 5 */
88 O_IPTTL, /* arg1 = TTL */
89
90 O_IPVER, /* arg1 = version */
91 O_UID, /* u32 = id */
92 O_GID, /* u32 = id */
93 O_ESTAB, /* none (tcp established) */
94 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */
95 O_TCPWIN, /* arg1 = desired win */
96 O_TCPSEQ, /* u32 = desired seq. */
97 O_TCPACK, /* u32 = desired seq. */
98 O_ICMPTYPE, /* u32 = icmp bitmap */
99 O_TCPOPTS, /* arg1 = 2*u8 bitmap */
100
101 O_VERREVPATH, /* none */
102 O_VERSRCREACH, /* none */
103
104 O_PROBE_STATE, /* none */
105 O_KEEP_STATE, /* none */
106 O_LIMIT, /* ipfw_insn_limit */
107 O_LIMIT_PARENT, /* dyn_type, not an opcode. */
108
109 /*
110 * These are really 'actions'.
111 */
112
113 O_LOG, /* ipfw_insn_log */
114 O_PROB, /* u32 = match probability */
115
116 O_CHECK_STATE, /* none */
117 O_ACCEPT, /* none */
118 O_DENY, /* none */
119 O_REJECT, /* arg1=icmp arg (same as deny) */
120 O_COUNT, /* none */
121 O_SKIPTO, /* arg1=next rule number */
122 O_PIPE, /* arg1=pipe number */
123 O_QUEUE, /* arg1=queue number */
124 O_DIVERT, /* arg1=port number */
125 O_TEE, /* arg1=port number */
126 O_FORWARD_IP, /* fwd sockaddr */
127 O_FORWARD_MAC, /* fwd mac */
128
129 /*
130 * More opcodes.
131 */
132 O_IPSEC, /* has ipsec history */
133 O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */
134 O_IP_DST_LOOKUP, /* arg1=table number, u32=value */
135 O_ANTISPOOF, /* none */
136 O_JAIL, /* u32 = id */
137 O_ALTQ, /* u32 = altq classif. qid */
138 O_DIVERTED, /* arg1=bitmap (1:loop, 2:out) */
139 O_TCPDATALEN, /* arg1 = tcp data len */
140
141 O_LAST_OPCODE /* not an opcode! */
142 };
143
144 /*
145 * Template for instructions.
146 *
147 * ipfw_insn is used for all instructions which require no operands,
148 * a single 16-bit value (arg1), or a couple of 8-bit values.
149 *
150 * For other instructions which require different/larger arguments
151 * we have derived structures, ipfw_insn_*.
152 *
153 * The size of the instruction (in 32-bit words) is in the low
154 * 6 bits of "len". The 2 remaining bits are used to implement
155 * NOT and OR on individual instructions. Given a type, you can
156 * compute the length to be put in "len" using F_INSN_SIZE(t)
157 *
158 * F_NOT negates the match result of the instruction.
159 *
160 * F_OR is used to build or blocks. By default, instructions
161 * are evaluated as part of a logical AND. An "or" block
162 * { X or Y or Z } contains F_OR set in all but the last
163 * instruction of the block. A match will cause the code
164 * to skip past the last instruction of the block.
165 *
166 * NOTA BENE: in a couple of places we assume that
167 * sizeof(ipfw_insn) == sizeof(u_int32_t)
168 * this needs to be fixed.
169 *
170 */
171 typedef struct _ipfw_insn { /* template for instructions */
172 enum ipfw_opcodes opcode:8;
173 u_int8_t len; /* numer of 32-byte words */
174 #define F_NOT 0x80
175 #define F_OR 0x40
176 #define F_LEN_MASK 0x3f
177 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
178
179 u_int16_t arg1;
180 } ipfw_insn;
181
182 /*
183 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of
184 * a given type.
185 */
186 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
187
188 /*
189 * This is used to store an array of 16-bit entries (ports etc.)
190 */
191 typedef struct _ipfw_insn_u16 {
192 ipfw_insn o;
193 u_int16_t ports[2]; /* there may be more */
194 } ipfw_insn_u16;
195
196 /*
197 * This is used to store an array of 32-bit entries
198 * (uid, single IPv4 addresses etc.)
199 */
200 typedef struct _ipfw_insn_u32 {
201 ipfw_insn o;
202 u_int32_t d[1]; /* one or more */
203 } ipfw_insn_u32;
204
205 /*
206 * This is used to store IP addr-mask pairs.
207 */
208 typedef struct _ipfw_insn_ip {
209 ipfw_insn o;
210 struct in_addr addr;
211 struct in_addr mask;
212 } ipfw_insn_ip;
213
214 /*
215 * This is used to forward to a given address (ip).
216 */
217 typedef struct _ipfw_insn_sa {
218 ipfw_insn o;
219 struct sockaddr_in sa;
220 } ipfw_insn_sa;
221
222 /*
223 * This is used for MAC addr-mask pairs.
224 */
225 typedef struct _ipfw_insn_mac {
226 ipfw_insn o;
227 u_char addr[12]; /* dst[6] + src[6] */
228 u_char mask[12]; /* dst[6] + src[6] */
229 } ipfw_insn_mac;
230
231 /*
232 * This is used for interface match rules (recv xx, xmit xx).
233 */
234 typedef struct _ipfw_insn_if {
235 ipfw_insn o;
236 union {
237 struct in_addr ip;
238 int glob;
239 } p;
240 char name[IFNAMSIZ];
241 } ipfw_insn_if;
242
243 /*
244 * This is used for pipe and queue actions, which need to store
245 * a single pointer (which can have different size on different
246 * architectures.
247 * Note that, because of previous instructions, pipe_ptr might
248 * be unaligned in the overall structure, so it needs to be
249 * manipulated with care.
250 */
251 typedef struct _ipfw_insn_pipe {
252 ipfw_insn o;
253 void *pipe_ptr; /* XXX */
254 } ipfw_insn_pipe;
255
256 /*
257 * This is used for storing an altq queue id number.
258 */
259 typedef struct _ipfw_insn_altq {
260 ipfw_insn o;
261 u_int32_t qid;
262 } ipfw_insn_altq;
263
264 /*
265 * This is used for limit rules.
266 */
267 typedef struct _ipfw_insn_limit {
268 ipfw_insn o;
269 u_int8_t _pad;
270 u_int8_t limit_mask; /* combination of DYN_* below */
271 #define DYN_SRC_ADDR 0x1
272 #define DYN_SRC_PORT 0x2
273 #define DYN_DST_ADDR 0x4
274 #define DYN_DST_PORT 0x8
275
276 u_int16_t conn_limit;
277 } ipfw_insn_limit;
278
279 /*
280 * This is used for log instructions.
281 */
282 typedef struct _ipfw_insn_log {
283 ipfw_insn o;
284 u_int32_t max_log; /* how many do we log -- 0 = all */
285 u_int32_t log_left; /* how many left to log */
286 } ipfw_insn_log;
287
288 /*
289 * Here we have the structure representing an ipfw rule.
290 *
291 * It starts with a general area (with link fields and counters)
292 * followed by an array of one or more instructions, which the code
293 * accesses as an array of 32-bit values.
294 *
295 * Given a rule pointer r:
296 *
297 * r->cmd is the start of the first instruction.
298 * ACTION_PTR(r) is the start of the first action (things to do
299 * once a rule matched).
300 *
301 * When assembling instruction, remember the following:
302 *
303 * + if a rule has a "keep-state" (or "limit") option, then the
304 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE
305 * + if a rule has a "log" option, then the first action
306 * (at ACTION_PTR(r)) MUST be O_LOG
307 * + if a rule has an "altq" option, it comes after "log"
308 *
309 * NOTE: we use a simple linked list of rules because we never need
310 * to delete a rule without scanning the list. We do not use
311 * queue(3) macros for portability and readability.
312 */
313
314 struct ip_fw {
315 struct ip_fw *next; /* linked list of rules */
316 struct ip_fw *next_rule; /* ptr to next [skipto] rule */
317 /* 'next_rule' is used to pass up 'set_disable' status */
318
319 u_int16_t act_ofs; /* offset of action in 32-bit units */
320 u_int16_t cmd_len; /* # of 32-bit words in cmd */
321 u_int16_t rulenum; /* rule number */
322 u_int8_t set; /* rule set (0..31) */
323 #define RESVD_SET 31 /* set for default and persistent rules */
324 u_int8_t _pad; /* padding */
325
326 /* These fields are present in all rules. */
327 u_int64_t pcnt; /* Packet counter */
328 u_int64_t bcnt; /* Byte counter */
329 u_int32_t timestamp; /* tv_sec of last match */
330
331 ipfw_insn cmd[1]; /* storage for commands */
332 };
333
334 #define ACTION_PTR(rule) \
335 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
336
337 #define RULESIZE(rule) (sizeof(struct ip_fw) + \
338 ((struct ip_fw *)(rule))->cmd_len * 4 - 4)
339
340 /*
341 * This structure is used as a flow mask and a flow id for various
342 * parts of the code.
343 */
344 struct ipfw_flow_id {
345 u_int32_t dst_ip;
346 u_int32_t src_ip;
347 u_int16_t dst_port;
348 u_int16_t src_port;
349 u_int8_t proto;
350 u_int8_t flags; /* protocol-specific flags */
351 };
352
353 /*
354 * Dynamic ipfw rule.
355 */
356 typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
357
358 struct _ipfw_dyn_rule {
359 ipfw_dyn_rule *next; /* linked list of rules. */
360 struct ip_fw *rule; /* pointer to rule */
361 /* 'rule' is used to pass up the rule number (from the parent) */
362
363 ipfw_dyn_rule *parent; /* pointer to parent rule */
364 u_int64_t pcnt; /* packet match counter */
365 u_int64_t bcnt; /* byte match counter */
366 struct ipfw_flow_id id; /* (masked) flow id */
367 u_int32_t expire; /* expire time */
368 u_int32_t bucket; /* which bucket in hash table */
369 u_int32_t state; /* state of this rule (typically a
370 * combination of TCP flags)
371 */
372 u_int32_t ack_fwd; /* most recent ACKs in forward */
373 u_int32_t ack_rev; /* and reverse directions (used */
374 /* to generate keepalives) */
375 u_int16_t dyn_type; /* rule type */
376 u_int16_t count; /* refcount */
377 };
378
379 /*
380 * Definitions for IP option names.
381 */
382 #define IP_FW_IPOPT_LSRR 0x01
383 #define IP_FW_IPOPT_SSRR 0x02
384 #define IP_FW_IPOPT_RR 0x04
385 #define IP_FW_IPOPT_TS 0x08
386
387 /*
388 * Definitions for TCP option names.
389 */
390 #define IP_FW_TCPOPT_MSS 0x01
391 #define IP_FW_TCPOPT_WINDOW 0x02
392 #define IP_FW_TCPOPT_SACK 0x04
393 #define IP_FW_TCPOPT_TS 0x08
394 #define IP_FW_TCPOPT_CC 0x10
395
396 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
397
398 /*
399 * These are used for lookup tables.
400 */
401 typedef struct _ipfw_table_entry {
402 in_addr_t addr; /* network address */
403 u_int32_t value; /* value */
404 u_int16_t tbl; /* table number */
405 u_int8_t masklen; /* mask length */
406 } ipfw_table_entry;
407
408 typedef struct _ipfw_table {
409 u_int32_t size; /* size of entries in bytes */
410 u_int32_t cnt; /* # of entries */
411 u_int16_t tbl; /* table number */
412 ipfw_table_entry ent[0]; /* entries */
413 } ipfw_table;
414
415 /*
416 * Main firewall chains definitions and global var's definitions.
417 */
418 #ifdef _KERNEL
419
420 #define IP_FW_PORT_DYNT_FLAG 0x00010000
421 #define IP_FW_PORT_TEE_FLAG 0x00020000
422 #define IP_FW_PORT_DENY_FLAG 0x00040000
423 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000
424 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000
425
426 /*
427 * Arguments for calling ipfw_chk() and dummynet_io(). We put them
428 * all into a structure because this way it is easier and more
429 * efficient to pass variables around and extend the interface.
430 */
431 struct ip_fw_args {
432 struct mbuf *m; /* the mbuf chain */
433 struct ifnet *oif; /* output interface */
434 struct sockaddr_in *next_hop; /* forward address */
435 struct ip_fw *rule; /* matching rule */
436 struct ether_header *eh; /* for bridged packets */
437
438 int flags; /* for dummynet */
439
440 struct ipfw_flow_id f_id; /* grabbed from IP header */
441 u_int32_t retval;
442 struct inpcb *inp;
443 };
444
445 /*
446 * Function definitions.
447 */
448
449 /* Firewall hooks */
450 struct sockopt;
451 struct dn_flow_set;
452
453 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
454 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
455
456 int ipfw_chk(struct ip_fw_args *);
457
458 int ipfw_init(void);
459 void ipfw_destroy(void);
460
461 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */
462
463 typedef int ip_fw_ctl_t(struct sockopt *);
464 extern ip_fw_ctl_t *ip_fw_ctl_ptr;
465 extern int fw_one_pass;
466 extern int fw_enable;
467
468 /* For kernel ipfw_ether and ipfw_bridge. */
469 typedef int ip_fw_chk_t(struct ip_fw_args *args);
470 extern ip_fw_chk_t *ip_fw_chk_ptr;
471 #define IPFW_LOADED (ip_fw_chk_ptr != NULL)
472
473 #endif /* _KERNEL */
474 #endif /* _IPFW2_H */
Cache object: effed2f556f87f75fa5d4b1f6843ad74
|