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/6.0/sys/netinet/ip_fw.h 149317 2005-08-20 08:36:57Z bz $
26 */
27
28 #ifndef _IPFW2_H
29 #define _IPFW2_H
30
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. When adding new opcodes, they should
48 * be appended to the end of the opcode list before O_LAST_OPCODE,
49 * this will prevent the ABI from being broken, otherwise users
50 * will have to recompile ipfw(8) when they update the kernel.
51 */
52
53 enum ipfw_opcodes { /* arguments (4 byte each) */
54 O_NOP,
55
56 O_IP_SRC, /* u32 = IP */
57 O_IP_SRC_MASK, /* ip = IP/mask */
58 O_IP_SRC_ME, /* none */
59 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */
60
61 O_IP_DST, /* u32 = IP */
62 O_IP_DST_MASK, /* ip = IP/mask */
63 O_IP_DST_ME, /* none */
64 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */
65
66 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */
67 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */
68 O_PROTO, /* arg1=protocol */
69
70 O_MACADDR2, /* 2 mac addr:mask */
71 O_MAC_TYPE, /* same as srcport */
72
73 O_LAYER2, /* none */
74 O_IN, /* none */
75 O_FRAG, /* none */
76
77 O_RECV, /* none */
78 O_XMIT, /* none */
79 O_VIA, /* none */
80
81 O_IPOPT, /* arg1 = 2*u8 bitmap */
82 O_IPLEN, /* arg1 = len */
83 O_IPID, /* arg1 = id */
84
85 O_IPTOS, /* arg1 = id */
86 O_IPPRECEDENCE, /* arg1 = precedence << 5 */
87 O_IPTTL, /* arg1 = TTL */
88
89 O_IPVER, /* arg1 = version */
90 O_UID, /* u32 = id */
91 O_GID, /* u32 = id */
92 O_ESTAB, /* none (tcp established) */
93 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */
94 O_TCPWIN, /* arg1 = desired win */
95 O_TCPSEQ, /* u32 = desired seq. */
96 O_TCPACK, /* u32 = desired seq. */
97 O_ICMPTYPE, /* u32 = icmp bitmap */
98 O_TCPOPTS, /* arg1 = 2*u8 bitmap */
99
100 O_VERREVPATH, /* none */
101 O_VERSRCREACH, /* none */
102
103 O_PROBE_STATE, /* none */
104 O_KEEP_STATE, /* none */
105 O_LIMIT, /* ipfw_insn_limit */
106 O_LIMIT_PARENT, /* dyn_type, not an opcode. */
107
108 /*
109 * These are really 'actions'.
110 */
111
112 O_LOG, /* ipfw_insn_log */
113 O_PROB, /* u32 = match probability */
114
115 O_CHECK_STATE, /* none */
116 O_ACCEPT, /* none */
117 O_DENY, /* none */
118 O_REJECT, /* arg1=icmp arg (same as deny) */
119 O_COUNT, /* none */
120 O_SKIPTO, /* arg1=next rule number */
121 O_PIPE, /* arg1=pipe number */
122 O_QUEUE, /* arg1=queue number */
123 O_DIVERT, /* arg1=port number */
124 O_TEE, /* arg1=port number */
125 O_FORWARD_IP, /* fwd sockaddr */
126 O_FORWARD_MAC, /* fwd mac */
127
128 /*
129 * More opcodes.
130 */
131 O_IPSEC, /* has ipsec history */
132 O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */
133 O_IP_DST_LOOKUP, /* arg1=table number, u32=value */
134 O_ANTISPOOF, /* none */
135 O_JAIL, /* u32 = id */
136 O_ALTQ, /* u32 = altq classif. qid */
137 O_DIVERTED, /* arg1=bitmap (1:loop, 2:out) */
138 O_TCPDATALEN, /* arg1 = tcp data len */
139 O_IP6_SRC, /* address without mask */
140 O_IP6_SRC_ME, /* my addresses */
141 O_IP6_SRC_MASK, /* address with the mask */
142 O_IP6_DST,
143 O_IP6_DST_ME,
144 O_IP6_DST_MASK,
145 O_FLOW6ID, /* for flow id tag in the ipv6 pkt */
146 O_ICMP6TYPE, /* icmp6 packet type filtering */
147 O_EXT_HDR, /* filtering for ipv6 extension header */
148 O_IP6,
149
150 /*
151 * actions for ng_ipfw
152 */
153 O_NETGRAPH, /* send to ng_ipfw */
154 O_NGTEE, /* copy to ng_ipfw */
155
156 O_IP4,
157
158 O_UNREACH6, /* arg1=icmpv6 code arg (deny) */
159
160 O_LAST_OPCODE /* not an opcode! */
161 };
162
163 /*
164 * The extension header are filtered only for presence using a bit
165 * vector with a flag for each header.
166 */
167 #define EXT_FRAGMENT 0x1
168 #define EXT_HOPOPTS 0x2
169 #define EXT_ROUTING 0x4
170 #define EXT_AH 0x8
171 #define EXT_ESP 0x10
172 #define EXT_DSTOPTS 0x20
173
174 /*
175 * Template for instructions.
176 *
177 * ipfw_insn is used for all instructions which require no operands,
178 * a single 16-bit value (arg1), or a couple of 8-bit values.
179 *
180 * For other instructions which require different/larger arguments
181 * we have derived structures, ipfw_insn_*.
182 *
183 * The size of the instruction (in 32-bit words) is in the low
184 * 6 bits of "len". The 2 remaining bits are used to implement
185 * NOT and OR on individual instructions. Given a type, you can
186 * compute the length to be put in "len" using F_INSN_SIZE(t)
187 *
188 * F_NOT negates the match result of the instruction.
189 *
190 * F_OR is used to build or blocks. By default, instructions
191 * are evaluated as part of a logical AND. An "or" block
192 * { X or Y or Z } contains F_OR set in all but the last
193 * instruction of the block. A match will cause the code
194 * to skip past the last instruction of the block.
195 *
196 * NOTA BENE: in a couple of places we assume that
197 * sizeof(ipfw_insn) == sizeof(u_int32_t)
198 * this needs to be fixed.
199 *
200 */
201 typedef struct _ipfw_insn { /* template for instructions */
202 enum ipfw_opcodes opcode:8;
203 u_int8_t len; /* numer of 32-byte words */
204 #define F_NOT 0x80
205 #define F_OR 0x40
206 #define F_LEN_MASK 0x3f
207 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
208
209 u_int16_t arg1;
210 } ipfw_insn;
211
212 /*
213 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of
214 * a given type.
215 */
216 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t))
217
218 /*
219 * This is used to store an array of 16-bit entries (ports etc.)
220 */
221 typedef struct _ipfw_insn_u16 {
222 ipfw_insn o;
223 u_int16_t ports[2]; /* there may be more */
224 } ipfw_insn_u16;
225
226 /*
227 * This is used to store an array of 32-bit entries
228 * (uid, single IPv4 addresses etc.)
229 */
230 typedef struct _ipfw_insn_u32 {
231 ipfw_insn o;
232 u_int32_t d[1]; /* one or more */
233 } ipfw_insn_u32;
234
235 /*
236 * This is used to store IP addr-mask pairs.
237 */
238 typedef struct _ipfw_insn_ip {
239 ipfw_insn o;
240 struct in_addr addr;
241 struct in_addr mask;
242 } ipfw_insn_ip;
243
244 /*
245 * This is used to forward to a given address (ip).
246 */
247 typedef struct _ipfw_insn_sa {
248 ipfw_insn o;
249 struct sockaddr_in sa;
250 } ipfw_insn_sa;
251
252 /*
253 * This is used for MAC addr-mask pairs.
254 */
255 typedef struct _ipfw_insn_mac {
256 ipfw_insn o;
257 u_char addr[12]; /* dst[6] + src[6] */
258 u_char mask[12]; /* dst[6] + src[6] */
259 } ipfw_insn_mac;
260
261 /*
262 * This is used for interface match rules (recv xx, xmit xx).
263 */
264 typedef struct _ipfw_insn_if {
265 ipfw_insn o;
266 union {
267 struct in_addr ip;
268 int glob;
269 } p;
270 char name[IFNAMSIZ];
271 } ipfw_insn_if;
272
273 /*
274 * This is used for pipe and queue actions, which need to store
275 * a single pointer (which can have different size on different
276 * architectures.
277 * Note that, because of previous instructions, pipe_ptr might
278 * be unaligned in the overall structure, so it needs to be
279 * manipulated with care.
280 */
281 typedef struct _ipfw_insn_pipe {
282 ipfw_insn o;
283 void *pipe_ptr; /* XXX */
284 } ipfw_insn_pipe;
285
286 /*
287 * This is used for storing an altq queue id number.
288 */
289 typedef struct _ipfw_insn_altq {
290 ipfw_insn o;
291 u_int32_t qid;
292 } ipfw_insn_altq;
293
294 /*
295 * This is used for limit rules.
296 */
297 typedef struct _ipfw_insn_limit {
298 ipfw_insn o;
299 u_int8_t _pad;
300 u_int8_t limit_mask; /* combination of DYN_* below */
301 #define DYN_SRC_ADDR 0x1
302 #define DYN_SRC_PORT 0x2
303 #define DYN_DST_ADDR 0x4
304 #define DYN_DST_PORT 0x8
305
306 u_int16_t conn_limit;
307 } ipfw_insn_limit;
308
309 /*
310 * This is used for log instructions.
311 */
312 typedef struct _ipfw_insn_log {
313 ipfw_insn o;
314 u_int32_t max_log; /* how many do we log -- 0 = all */
315 u_int32_t log_left; /* how many left to log */
316 } ipfw_insn_log;
317
318 /* Apply ipv6 mask on ipv6 addr */
319 #define APPLY_MASK(addr,mask) \
320 (addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \
321 (addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \
322 (addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \
323 (addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3];
324
325 /* Structure for ipv6 */
326 typedef struct _ipfw_insn_ip6 {
327 ipfw_insn o;
328 struct in6_addr addr6;
329 struct in6_addr mask6;
330 } ipfw_insn_ip6;
331
332 /* Used to support icmp6 types */
333 typedef struct _ipfw_insn_icmp6 {
334 ipfw_insn o;
335 uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h
336 * define ICMP6_MAXTYPE
337 * as follows: n = ICMP6_MAXTYPE/32 + 1
338 * Actually is 203
339 */
340 } ipfw_insn_icmp6;
341
342 /*
343 * Here we have the structure representing an ipfw rule.
344 *
345 * It starts with a general area (with link fields and counters)
346 * followed by an array of one or more instructions, which the code
347 * accesses as an array of 32-bit values.
348 *
349 * Given a rule pointer r:
350 *
351 * r->cmd is the start of the first instruction.
352 * ACTION_PTR(r) is the start of the first action (things to do
353 * once a rule matched).
354 *
355 * When assembling instruction, remember the following:
356 *
357 * + if a rule has a "keep-state" (or "limit") option, then the
358 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE
359 * + if a rule has a "log" option, then the first action
360 * (at ACTION_PTR(r)) MUST be O_LOG
361 * + if a rule has an "altq" option, it comes after "log"
362 *
363 * NOTE: we use a simple linked list of rules because we never need
364 * to delete a rule without scanning the list. We do not use
365 * queue(3) macros for portability and readability.
366 */
367
368 struct ip_fw {
369 struct ip_fw *next; /* linked list of rules */
370 struct ip_fw *next_rule; /* ptr to next [skipto] rule */
371 /* 'next_rule' is used to pass up 'set_disable' status */
372
373 u_int16_t act_ofs; /* offset of action in 32-bit units */
374 u_int16_t cmd_len; /* # of 32-bit words in cmd */
375 u_int16_t rulenum; /* rule number */
376 u_int8_t set; /* rule set (0..31) */
377 #define RESVD_SET 31 /* set for default and persistent rules */
378 u_int8_t _pad; /* padding */
379
380 /* These fields are present in all rules. */
381 u_int64_t pcnt; /* Packet counter */
382 u_int64_t bcnt; /* Byte counter */
383 u_int32_t timestamp; /* tv_sec of last match */
384
385 ipfw_insn cmd[1]; /* storage for commands */
386 };
387
388 #define ACTION_PTR(rule) \
389 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) )
390
391 #define RULESIZE(rule) (sizeof(struct ip_fw) + \
392 ((struct ip_fw *)(rule))->cmd_len * 4 - 4)
393
394 /*
395 * This structure is used as a flow mask and a flow id for various
396 * parts of the code.
397 */
398 struct ipfw_flow_id {
399 u_int32_t dst_ip;
400 u_int32_t src_ip;
401 u_int16_t dst_port;
402 u_int16_t src_port;
403 u_int8_t proto;
404 u_int8_t flags; /* protocol-specific flags */
405 uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */
406 struct in6_addr dst_ip6; /* could also store MAC addr! */
407 struct in6_addr src_ip6;
408 u_int32_t flow_id6;
409 u_int32_t frag_id6;
410 };
411
412 #define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6)
413
414 /*
415 * Dynamic ipfw rule.
416 */
417 typedef struct _ipfw_dyn_rule ipfw_dyn_rule;
418
419 struct _ipfw_dyn_rule {
420 ipfw_dyn_rule *next; /* linked list of rules. */
421 struct ip_fw *rule; /* pointer to rule */
422 /* 'rule' is used to pass up the rule number (from the parent) */
423
424 ipfw_dyn_rule *parent; /* pointer to parent rule */
425 u_int64_t pcnt; /* packet match counter */
426 u_int64_t bcnt; /* byte match counter */
427 struct ipfw_flow_id id; /* (masked) flow id */
428 u_int32_t expire; /* expire time */
429 u_int32_t bucket; /* which bucket in hash table */
430 u_int32_t state; /* state of this rule (typically a
431 * combination of TCP flags)
432 */
433 u_int32_t ack_fwd; /* most recent ACKs in forward */
434 u_int32_t ack_rev; /* and reverse directions (used */
435 /* to generate keepalives) */
436 u_int16_t dyn_type; /* rule type */
437 u_int16_t count; /* refcount */
438 };
439
440 /*
441 * Definitions for IP option names.
442 */
443 #define IP_FW_IPOPT_LSRR 0x01
444 #define IP_FW_IPOPT_SSRR 0x02
445 #define IP_FW_IPOPT_RR 0x04
446 #define IP_FW_IPOPT_TS 0x08
447
448 /*
449 * Definitions for TCP option names.
450 */
451 #define IP_FW_TCPOPT_MSS 0x01
452 #define IP_FW_TCPOPT_WINDOW 0x02
453 #define IP_FW_TCPOPT_SACK 0x04
454 #define IP_FW_TCPOPT_TS 0x08
455 #define IP_FW_TCPOPT_CC 0x10
456
457 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */
458 #define ICMP6_UNREACH_RST 0x100 /* fake ICMPv6 code (send a TCP RST) */
459
460 /*
461 * These are used for lookup tables.
462 */
463 typedef struct _ipfw_table_entry {
464 in_addr_t addr; /* network address */
465 u_int32_t value; /* value */
466 u_int16_t tbl; /* table number */
467 u_int8_t masklen; /* mask length */
468 } ipfw_table_entry;
469
470 typedef struct _ipfw_table {
471 u_int32_t size; /* size of entries in bytes */
472 u_int32_t cnt; /* # of entries */
473 u_int16_t tbl; /* table number */
474 ipfw_table_entry ent[0]; /* entries */
475 } ipfw_table;
476
477 /*
478 * Main firewall chains definitions and global var's definitions.
479 */
480 #ifdef _KERNEL
481
482 /* Return values from ipfw_chk() */
483 enum {
484 IP_FW_PASS = 0,
485 IP_FW_DENY,
486 IP_FW_DIVERT,
487 IP_FW_TEE,
488 IP_FW_DUMMYNET,
489 IP_FW_NETGRAPH,
490 IP_FW_NGTEE,
491 };
492
493 /* flags for divert mtag */
494 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000
495 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000
496
497 /*
498 * Structure for collecting parameters to dummynet for ip6_output forwarding
499 */
500 struct _ip6dn_args {
501 struct ip6_pktopts *opt_or;
502 struct route_in6 ro_or;
503 int flags_or;
504 struct ip6_moptions *im6o_or;
505 struct ifnet *origifp_or;
506 struct ifnet *ifp_or;
507 struct sockaddr_in6 dst_or;
508 u_long mtu_or;
509 struct route_in6 ro_pmtu_or;
510 };
511
512 /*
513 * Arguments for calling ipfw_chk() and dummynet_io(). We put them
514 * all into a structure because this way it is easier and more
515 * efficient to pass variables around and extend the interface.
516 */
517 struct ip_fw_args {
518 struct mbuf *m; /* the mbuf chain */
519 struct ifnet *oif; /* output interface */
520 struct sockaddr_in *next_hop; /* forward address */
521 struct ip_fw *rule; /* matching rule */
522 struct ether_header *eh; /* for bridged packets */
523
524 int flags; /* for dummynet */
525
526 struct ipfw_flow_id f_id; /* grabbed from IP header */
527 u_int32_t cookie; /* a cookie depending on rule action */
528 struct inpcb *inp;
529
530 struct _ip6dn_args dummypar; /* dummynet->ip6_output */
531 };
532
533 /*
534 * Function definitions.
535 */
536
537 /* Firewall hooks */
538 struct sockopt;
539 struct dn_flow_set;
540
541 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
542 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp);
543
544 int ipfw_chk(struct ip_fw_args *);
545
546 int ipfw_init(void);
547 void ipfw_destroy(void);
548
549 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */
550
551 typedef int ip_fw_ctl_t(struct sockopt *);
552 extern ip_fw_ctl_t *ip_fw_ctl_ptr;
553 extern int fw_one_pass;
554 extern int fw_enable;
555
556 /* For kernel ipfw_ether and ipfw_bridge. */
557 typedef int ip_fw_chk_t(struct ip_fw_args *args);
558 extern ip_fw_chk_t *ip_fw_chk_ptr;
559 #define IPFW_LOADED (ip_fw_chk_ptr != NULL)
560
561 #endif /* _KERNEL */
562 #endif /* _IPFW2_H */
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