?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
- Undefine temporary macro
[dragonfly/netmp.git] / sys / net / ipfw / ip_fw2.c
blob80fe090ebac40f4cd9a48cfdd4f959c057d5c532
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: src/sys/netinet/ip_fw2.c,v 1.6.2.12 2003/04/08 10:42:32 maxim Exp $
26 * $DragonFly: src/sys/net/ipfw/ip_fw2.c,v 1.56 2008/07/31 12:09:00 sephe Exp $
27 */
28
29 #define DEB(x)
30 #define DDB(x) x
31
32 /*
33 * Implement IP packet firewall (new version)
34 */
35
36 #ifndef KLD_MODULE
37 #include "opt_ipfw.h"
38 #include "opt_ipdn.h"
39 #include "opt_ipdivert.h"
40 #include "opt_inet.h"
41 #ifndef INET
42 #error IPFIREWALL requires INET.
43 #endif /* INET */
44 #endif
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/malloc.h>
49 #include <sys/mbuf.h>
50 #include <sys/kernel.h>
51 #include <sys/proc.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/sysctl.h>
55 #include <sys/syslog.h>
56 #include <sys/thread2.h>
57 #include <sys/ucred.h>
58 #include <sys/in_cksum.h>
59
60 #include <net/if.h>
61 #include <net/route.h>
62 #include <net/netmsg2.h>
63
64 #include <netinet/in.h>
65 #include <netinet/in_systm.h>
66 #include <netinet/in_var.h>
67 #include <netinet/in_pcb.h>
68 #include <netinet/ip.h>
69 #include <netinet/ip_var.h>
70 #include <netinet/ip_icmp.h>
71 #include "ip_fw.h"
72 #include <net/dummynet/ip_dummynet.h>
73 #include <netinet/tcp.h>
74 #include <netinet/tcp_timer.h>
75 #include <netinet/tcp_var.h>
76 #include <netinet/tcpip.h>
77 #include <netinet/udp.h>
78 #include <netinet/udp_var.h>
79
80 #include <netinet/if_ether.h> /* XXX for ETHERTYPE_IP */
81
82 /*
83 * set_disable contains one bit per set value (0..31).
84 * If the bit is set, all rules with the corresponding set
85 * are disabled. Set 31 is reserved for the default rule
86 * and CANNOT be disabled.
87 */
88 static uint32_t set_disable;
89
90 static int fw_verbose;
91 static int verbose_limit;
92
93 #ifdef KLD_MODULE
94 static int ipfw_refcnt;
95 #endif
96
97 static struct callout ipfw_timeout_h;
98 #define IPFW_DEFAULT_RULE 65535
99
100 /*
101 * list of rules for layer 3
102 */
103 static struct ip_fw *layer3_chain;
104
105 MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
106
107 static int fw_debug = 1;
108 static int autoinc_step = 100; /* bounded to 1..1000 in ipfw_add_rule() */
109
110 #ifdef SYSCTL_NODE
111 SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
112 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,
113 &fw_enable, 0, "Enable ipfw");
114 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, CTLFLAG_RW,
115 &autoinc_step, 0, "Rule number autincrement step");
116 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW,
117 &fw_one_pass, 0,
118 "Only do a single pass through ipfw when using dummynet(4)");
119 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW,
120 &fw_debug, 0, "Enable printing of debug ip_fw statements");
121 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW,
122 &fw_verbose, 0, "Log matches to ipfw rules");
123 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW,
124 &verbose_limit, 0, "Set upper limit of matches of ipfw rules logged");
125
126 /*
127 * Description of dynamic rules.
128 *
129 * Dynamic rules are stored in lists accessed through a hash table
130 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
131 * be modified through the sysctl variable dyn_buckets which is
132 * updated when the table becomes empty.
133 *
134 * XXX currently there is only one list, ipfw_dyn.
135 *
136 * When a packet is received, its address fields are first masked
137 * with the mask defined for the rule, then hashed, then matched
138 * against the entries in the corresponding list.
139 * Dynamic rules can be used for different purposes:
140 * + stateful rules;
141 * + enforcing limits on the number of sessions;
142 * + in-kernel NAT (not implemented yet)
143 *
144 * The lifetime of dynamic rules is regulated by dyn_*_lifetime,
145 * measured in seconds and depending on the flags.
146 *
147 * The total number of dynamic rules is stored in dyn_count.
148 * The max number of dynamic rules is dyn_max. When we reach
149 * the maximum number of rules we do not create anymore. This is
150 * done to avoid consuming too much memory, but also too much
151 * time when searching on each packet (ideally, we should try instead
152 * to put a limit on the length of the list on each bucket...).
153 *
154 * Each dynamic rule holds a pointer to the parent ipfw rule so
155 * we know what action to perform. Dynamic rules are removed when
156 * the parent rule is deleted. XXX we should make them survive.
157 *
158 * There are some limitations with dynamic rules -- we do not
159 * obey the 'randomized match', and we do not do multiple
160 * passes through the firewall. XXX check the latter!!!
161 */
162 static ipfw_dyn_rule **ipfw_dyn_v = NULL;
163 static uint32_t dyn_buckets = 256; /* must be power of 2 */
164 static uint32_t curr_dyn_buckets = 256; /* must be power of 2 */
165
166 /*
167 * Timeouts for various events in handing dynamic rules.
168 */
169 static uint32_t dyn_ack_lifetime = 300;
170 static uint32_t dyn_syn_lifetime = 20;
171 static uint32_t dyn_fin_lifetime = 1;
172 static uint32_t dyn_rst_lifetime = 1;
173 static uint32_t dyn_udp_lifetime = 10;
174 static uint32_t dyn_short_lifetime = 5;
175
176 /*
177 * Keepalives are sent if dyn_keepalive is set. They are sent every
178 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval
179 * seconds of lifetime of a rule.
180 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower
181 * than dyn_keepalive_period.
182 */
183
184 static uint32_t dyn_keepalive_interval = 20;
185 static uint32_t dyn_keepalive_period = 5;
186 static uint32_t dyn_keepalive = 1; /* do send keepalives */
187
188 static uint32_t static_count; /* # of static rules */
189 static uint32_t static_ioc_len; /* bytes of static rules */
190 static uint32_t dyn_count; /* # of dynamic rules */
191 static uint32_t dyn_max = 4096; /* max # of dynamic rules */
192
193 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW,
194 &dyn_buckets, 0, "Number of dyn. buckets");
195 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD,
196 &curr_dyn_buckets, 0, "Current Number of dyn. buckets");
197 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD,
198 &dyn_count, 0, "Number of dyn. rules");
199 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW,
200 &dyn_max, 0, "Max number of dyn. rules");
201 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD,
202 &static_count, 0, "Number of static rules");
203 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW,
204 &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks");
205 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW,
206 &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn");
207 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW,
208 &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin");
209 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW,
210 &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst");
211 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW,
212 &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP");
213 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW,
214 &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations");
215 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, CTLFLAG_RW,
216 &dyn_keepalive, 0, "Enable keepalives for dyn. rules");
217
218 #endif /* SYSCTL_NODE */
219
220 static struct ip_fw *ip_fw_default_rule;
221
222 static ip_fw_chk_t ipfw_chk;
223
224 static __inline int
225 ipfw_free_rule(struct ip_fw *rule)
226 {
227 KASSERT(rule->refcnt > 0, ("invalid refcnt %u\n", rule->refcnt));
228 atomic_subtract_int(&rule->refcnt, 1);
229 if (atomic_cmpset_int(&rule->refcnt, 0, 1)) {
230 kfree(rule, M_IPFW);
231 return 1;
232 }
233 return 0;
234 }
235
236 static void
237 ipfw_unref_rule(void *priv)
238 {
239 ipfw_free_rule(priv);
240 #ifdef KLD_MODULE
241 atomic_subtract_int(&ipfw_refcnt, 1);
242 #endif
243 }
244
245 static __inline void
246 ipfw_ref_rule(struct ip_fw *rule)
247 {
248 #ifdef KLD_MODULE
249 atomic_add_int(&ipfw_refcnt, 1);
250 #endif
251 atomic_add_int(&rule->refcnt, 1);
252 }
253
254 /*
255 * This macro maps an ip pointer into a layer3 header pointer of type T
256 */
257 #define L3HDR(T, ip) ((T *)((uint32_t *)(ip) + (ip)->ip_hl))
258
259 static __inline int
260 icmptype_match(struct ip *ip, ipfw_insn_u32 *cmd)
261 {
262 int type = L3HDR(struct icmp,ip)->icmp_type;
263
264 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1 << type)));
265 }
266
267 #define TT ((1 << ICMP_ECHO) | \
268 (1 << ICMP_ROUTERSOLICIT) | \
269 (1 << ICMP_TSTAMP) | \
270 (1 << ICMP_IREQ) | \
271 (1 << ICMP_MASKREQ))
272
273 static int
274 is_icmp_query(struct ip *ip)
275 {
276 int type = L3HDR(struct icmp, ip)->icmp_type;
277
278 return (type <= ICMP_MAXTYPE && (TT & (1 << type)));
279 }
280
281 #undef TT
282
283 /*
284 * The following checks use two arrays of 8 or 16 bits to store the
285 * bits that we want set or clear, respectively. They are in the
286 * low and high half of cmd->arg1 or cmd->d[0].
287 *
288 * We scan options and store the bits we find set. We succeed if
289 *
290 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear
291 *
292 * The code is sometimes optimized not to store additional variables.
293 */
294
295 static int
296 flags_match(ipfw_insn *cmd, uint8_t bits)
297 {
298 u_char want_clear;
299 bits = ~bits;
300
301 if (((cmd->arg1 & 0xff) & bits) != 0)
302 return 0; /* some bits we want set were clear */
303
304 want_clear = (cmd->arg1 >> 8) & 0xff;
305 if ((want_clear & bits) != want_clear)
306 return 0; /* some bits we want clear were set */
307 return 1;
308 }
309
310 static int
311 ipopts_match(struct ip *ip, ipfw_insn *cmd)
312 {
313 int optlen, bits = 0;
314 u_char *cp = (u_char *)(ip + 1);
315 int x = (ip->ip_hl << 2) - sizeof(struct ip);
316
317 for (; x > 0; x -= optlen, cp += optlen) {
318 int opt = cp[IPOPT_OPTVAL];
319
320 if (opt == IPOPT_EOL)
321 break;
322
323 if (opt == IPOPT_NOP) {
324 optlen = 1;
325 } else {
326 optlen = cp[IPOPT_OLEN];
327 if (optlen <= 0 || optlen > x)
328 return 0; /* invalid or truncated */
329 }
330
331 switch (opt) {
332 case IPOPT_LSRR:
333 bits |= IP_FW_IPOPT_LSRR;
334 break;
335
336 case IPOPT_SSRR:
337 bits |= IP_FW_IPOPT_SSRR;
338 break;
339
340 case IPOPT_RR:
341 bits |= IP_FW_IPOPT_RR;
342 break;
343
344 case IPOPT_TS:
345 bits |= IP_FW_IPOPT_TS;
346 break;
347
348 default:
349 break;
350 }
351 }
352 return (flags_match(cmd, bits));
353 }
354
355 static int
356 tcpopts_match(struct ip *ip, ipfw_insn *cmd)
357 {
358 int optlen, bits = 0;
359 struct tcphdr *tcp = L3HDR(struct tcphdr,ip);
360 u_char *cp = (u_char *)(tcp + 1);
361 int x = (tcp->th_off << 2) - sizeof(struct tcphdr);
362
363 for (; x > 0; x -= optlen, cp += optlen) {
364 int opt = cp[0];
365
366 if (opt == TCPOPT_EOL)
367 break;
368
369 if (opt == TCPOPT_NOP) {
370 optlen = 1;
371 } else {
372 optlen = cp[1];
373 if (optlen <= 0)
374 break;
375 }
376
377 switch (opt) {
378 case TCPOPT_MAXSEG:
379 bits |= IP_FW_TCPOPT_MSS;
380 break;
381
382 case TCPOPT_WINDOW:
383 bits |= IP_FW_TCPOPT_WINDOW;
384 break;
385
386 case TCPOPT_SACK_PERMITTED:
387 case TCPOPT_SACK:
388 bits |= IP_FW_TCPOPT_SACK;
389 break;
390
391 case TCPOPT_TIMESTAMP:
392 bits |= IP_FW_TCPOPT_TS;
393 break;
394
395 case TCPOPT_CC:
396 case TCPOPT_CCNEW:
397 case TCPOPT_CCECHO:
398 bits |= IP_FW_TCPOPT_CC;
399 break;
400
401 default:
402 break;
403 }
404 }
405 return (flags_match(cmd, bits));
406 }
407
408 static int
409 iface_match(struct ifnet *ifp, ipfw_insn_if *cmd)
410 {
411 if (ifp == NULL) /* no iface with this packet, match fails */
412 return 0;
413
414 /* Check by name or by IP address */
415 if (cmd->name[0] != '\0') { /* match by name */
416 /* Check name */
417 if (cmd->p.glob) {
418 if (kfnmatch(cmd->name, ifp->if_xname, 0) == 0)
419 return(1);
420 } else {
421 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0)
422 return(1);
423 }
424 } else {
425 struct ifaddr_container *ifac;
426
427 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
428 struct ifaddr *ia = ifac->ifa;
429
430 if (ia->ifa_addr == NULL)
431 continue;
432 if (ia->ifa_addr->sa_family != AF_INET)
433 continue;
434 if (cmd->p.ip.s_addr == ((struct sockaddr_in *)
435 (ia->ifa_addr))->sin_addr.s_addr)
436 return(1); /* match */
437 }
438 }
439 return(0); /* no match, fail ... */
440 }
441
442 static uint64_t norule_counter; /* counter for ipfw_log(NULL...) */
443
444 #define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
445
446 /*
447 * We enter here when we have a rule with O_LOG.
448 * XXX this function alone takes about 2Kbytes of code!
449 */
450 static void
451 ipfw_log(struct ip_fw *f, u_int hlen, struct ether_header *eh,
452 struct mbuf *m, struct ifnet *oif)
453 {
454 char *action;
455 int limit_reached = 0;
456 char action2[40], proto[48], fragment[28];
457
458 fragment[0] = '\0';
459 proto[0] = '\0';
460
461 if (f == NULL) { /* bogus pkt */
462 if (verbose_limit != 0 && norule_counter >= verbose_limit)
463 return;
464 norule_counter++;
465 if (norule_counter == verbose_limit)
466 limit_reached = verbose_limit;
467 action = "Refuse";
468 } else { /* O_LOG is the first action, find the real one */
469 ipfw_insn *cmd = ACTION_PTR(f);
470 ipfw_insn_log *l = (ipfw_insn_log *)cmd;
471
472 if (l->max_log != 0 && l->log_left == 0)
473 return;
474 l->log_left--;
475 if (l->log_left == 0)
476 limit_reached = l->max_log;
477 cmd += F_LEN(cmd); /* point to first action */
478 if (cmd->opcode == O_PROB)
479 cmd += F_LEN(cmd);
480
481 action = action2;
482 switch (cmd->opcode) {
483 case O_DENY:
484 action = "Deny";
485 break;
486
487 case O_REJECT:
488 if (cmd->arg1==ICMP_REJECT_RST) {
489 action = "Reset";
490 } else if (cmd->arg1==ICMP_UNREACH_HOST) {
491 action = "Reject";
492 } else {
493 ksnprintf(SNPARGS(action2, 0), "Unreach %d",
494 cmd->arg1);
495 }
496 break;
497
498 case O_ACCEPT:
499 action = "Accept";
500 break;
501
502 case O_COUNT:
503 action = "Count";
504 break;
505
506 case O_DIVERT:
507 ksnprintf(SNPARGS(action2, 0), "Divert %d", cmd->arg1);
508 break;
509
510 case O_TEE:
511 ksnprintf(SNPARGS(action2, 0), "Tee %d", cmd->arg1);
512 break;
513
514 case O_SKIPTO:
515 ksnprintf(SNPARGS(action2, 0), "SkipTo %d", cmd->arg1);
516 break;
517
518 case O_PIPE:
519 ksnprintf(SNPARGS(action2, 0), "Pipe %d", cmd->arg1);
520 break;
521
522 case O_QUEUE:
523 ksnprintf(SNPARGS(action2, 0), "Queue %d", cmd->arg1);
524 break;
525
526 case O_FORWARD_IP:
527 {
528 ipfw_insn_sa *sa = (ipfw_insn_sa *)cmd;
529 int len;
530
531 len = ksnprintf(SNPARGS(action2, 0),
532 "Forward to %s",
533 inet_ntoa(sa->sa.sin_addr));
534 if (sa->sa.sin_port) {
535 ksnprintf(SNPARGS(action2, len), ":%d",
536 sa->sa.sin_port);
537 }
538 }
539 break;
540
541 default:
542 action = "UNKNOWN";
543 break;
544 }
545 }
546
547 if (hlen == 0) { /* non-ip */
548 ksnprintf(SNPARGS(proto, 0), "MAC");
549 } else {
550 struct ip *ip = mtod(m, struct ip *);
551 /* these three are all aliases to the same thing */
552 struct icmp *const icmp = L3HDR(struct icmp, ip);
553 struct tcphdr *const tcp = (struct tcphdr *)icmp;
554 struct udphdr *const udp = (struct udphdr *)icmp;
555
556 int ip_off, offset, ip_len;
557 int len;
558
559 if (eh != NULL) { /* layer 2 packets are as on the wire */
560 ip_off = ntohs(ip->ip_off);
561 ip_len = ntohs(ip->ip_len);
562 } else {
563 ip_off = ip->ip_off;
564 ip_len = ip->ip_len;
565 }
566 offset = ip_off & IP_OFFMASK;
567 switch (ip->ip_p) {
568 case IPPROTO_TCP:
569 len = ksnprintf(SNPARGS(proto, 0), "TCP %s",
570 inet_ntoa(ip->ip_src));
571 if (offset == 0) {
572 ksnprintf(SNPARGS(proto, len), ":%d %s:%d",
573 ntohs(tcp->th_sport),
574 inet_ntoa(ip->ip_dst),
575 ntohs(tcp->th_dport));
576 } else {
577 ksnprintf(SNPARGS(proto, len), " %s",
578 inet_ntoa(ip->ip_dst));
579 }
580 break;
581
582 case IPPROTO_UDP:
583 len = ksnprintf(SNPARGS(proto, 0), "UDP %s",
584 inet_ntoa(ip->ip_src));
585 if (offset == 0) {
586 ksnprintf(SNPARGS(proto, len), ":%d %s:%d",
587 ntohs(udp->uh_sport),
588 inet_ntoa(ip->ip_dst),
589 ntohs(udp->uh_dport));
590 } else {
591 ksnprintf(SNPARGS(proto, len), " %s",
592 inet_ntoa(ip->ip_dst));
593 }
594 break;
595
596 case IPPROTO_ICMP:
597 if (offset == 0) {
598 len = ksnprintf(SNPARGS(proto, 0),
599 "ICMP:%u.%u ",
600 icmp->icmp_type,
601 icmp->icmp_code);
602 } else {
603 len = ksnprintf(SNPARGS(proto, 0), "ICMP ");
604 }
605 len += ksnprintf(SNPARGS(proto, len), "%s",
606 inet_ntoa(ip->ip_src));
607 ksnprintf(SNPARGS(proto, len), " %s",
608 inet_ntoa(ip->ip_dst));
609 break;
610
611 default:
612 len = ksnprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p,
613 inet_ntoa(ip->ip_src));
614 ksnprintf(SNPARGS(proto, len), " %s",
615 inet_ntoa(ip->ip_dst));
616 break;
617 }
618
619 if (ip_off & (IP_MF | IP_OFFMASK)) {
620 ksnprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)",
621 ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2),
622 offset << 3, (ip_off & IP_MF) ? "+" : "");
623 }
624 }
625
626 if (oif || m->m_pkthdr.rcvif) {
627 log(LOG_SECURITY | LOG_INFO,
628 "ipfw: %d %s %s %s via %s%s\n",
629 f ? f->rulenum : -1,
630 action, proto, oif ? "out" : "in",
631 oif ? oif->if_xname : m->m_pkthdr.rcvif->if_xname,
632 fragment);
633 } else {
634 log(LOG_SECURITY | LOG_INFO,
635 "ipfw: %d %s %s [no if info]%s\n",
636 f ? f->rulenum : -1,
637 action, proto, fragment);
638 }
639
640 if (limit_reached) {
641 log(LOG_SECURITY | LOG_NOTICE,
642 "ipfw: limit %d reached on entry %d\n",
643 limit_reached, f ? f->rulenum : -1);
644 }
645 }
646
647 #undef SNPARGS
648
649 /*
650 * IMPORTANT: the hash function for dynamic rules must be commutative
651 * in source and destination (ip,port), because rules are bidirectional
652 * and we want to find both in the same bucket.
653 */
654 static __inline int
655 hash_packet(struct ipfw_flow_id *id)
656 {
657 uint32_t i;
658
659 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
660 i &= (curr_dyn_buckets - 1);
661 return i;
662 }
663
664 /**
665 * unlink a dynamic rule from a chain. prev is a pointer to
666 * the previous one, q is a pointer to the rule to delete,
667 * head is a pointer to the head of the queue.
668 * Modifies q and potentially also head.
669 */
670 #define UNLINK_DYN_RULE(prev, head, q) \
671 do { \
672 ipfw_dyn_rule *old_q = q; \
673 \
674 /* remove a refcount to the parent */ \
675 if (q->dyn_type == O_LIMIT) \
676 q->parent->count--; \
677 DEB(kprintf("-- unlink entry 0x%08x %d -> 0x%08x %d, %d left\n", \
678 (q->id.src_ip), (q->id.src_port), \
679 (q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \
680 if (prev != NULL) \
681 prev->next = q = q->next; \
682 else \
683 head = q = q->next; \
684 KASSERT(dyn_count > 0, ("invalid dyn count %u\n", dyn_count)); \
685 dyn_count--; \
686 kfree(old_q, M_IPFW); \
687 } while (0)
688
689 #define TIME_LEQ(a, b) ((int)((a) - (b)) <= 0)
690
691 /**
692 * Remove dynamic rules pointing to "rule", or all of them if rule == NULL.
693 *
694 * If keep_me == NULL, rules are deleted even if not expired,
695 * otherwise only expired rules are removed.
696 *
697 * The value of the second parameter is also used to point to identify
698 * a rule we absolutely do not want to remove (e.g. because we are
699 * holding a reference to it -- this is the case with O_LIMIT_PARENT
700 * rules). The pointer is only used for comparison, so any non-null
701 * value will do.
702 */
703 static void
704 remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me)
705 {
706 static uint32_t last_remove = 0;
707
708 #define FORCE (keep_me == NULL)
709
710 ipfw_dyn_rule *prev, *q;
711 int i, pass = 0, max_pass = 0;
712
713 if (ipfw_dyn_v == NULL || dyn_count == 0)
714 return;
715 /* do not expire more than once per second, it is useless */
716 if (!FORCE && last_remove == time_second)
717 return;
718 last_remove = time_second;
719
720 /*
721 * because O_LIMIT refer to parent rules, during the first pass only
722 * remove child and mark any pending LIMIT_PARENT, and remove
723 * them in a second pass.
724 */
725 next_pass:
726 for (i = 0 ; i < curr_dyn_buckets ; i++) {
727 for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) {
728 /*
729 * Logic can become complex here, so we split tests.
730 */
731 if (q == keep_me)
732 goto next;
733 if (rule != NULL && rule != q->rule)
734 goto next; /* not the one we are looking for */
735 if (q->dyn_type == O_LIMIT_PARENT) {
736 /*
737 * handle parent in the second pass,
738 * record we need one.
739 */
740 max_pass = 1;
741 if (pass == 0)
742 goto next;
743 if (FORCE && q->count != 0 ) {
744 /* XXX should not happen! */
745 kprintf( "OUCH! cannot remove rule,"
746 " count %d\n", q->count);
747 }
748 } else {
749 if (!FORCE &&
750 !TIME_LEQ( q->expire, time_second ))
751 goto next;
752 }
753 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
754 continue;
755 next:
756 prev=q;
757 q=q->next;
758 }
759 }
760 if (pass++ < max_pass)
761 goto next_pass;
762
763 #undef FORCE
764 }
765
766
767 /**
768 * lookup a dynamic rule.
769 */
770 static ipfw_dyn_rule *
771 lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction,
772 struct tcphdr *tcp)
773 {
774 /*
775 * stateful ipfw extensions.
776 * Lookup into dynamic session queue
777 */
778 #define MATCH_REVERSE 0
779 #define MATCH_FORWARD 1
780 #define MATCH_NONE 2
781 #define MATCH_UNKNOWN 3
782 int i, dir = MATCH_NONE;
783 ipfw_dyn_rule *prev, *q=NULL;
784
785 if (ipfw_dyn_v == NULL)
786 goto done; /* not found */
787 i = hash_packet( pkt );
788 for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) {
789 if (q->dyn_type == O_LIMIT_PARENT)
790 goto next;
791 if (TIME_LEQ( q->expire, time_second)) { /* expire entry */
792 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
793 continue;
794 }
795 if ( pkt->proto == q->id.proto) {
796 if (pkt->src_ip == q->id.src_ip &&
797 pkt->dst_ip == q->id.dst_ip &&
798 pkt->src_port == q->id.src_port &&
799 pkt->dst_port == q->id.dst_port ) {
800 dir = MATCH_FORWARD;
801 break;
802 }
803 if (pkt->src_ip == q->id.dst_ip &&
804 pkt->dst_ip == q->id.src_ip &&
805 pkt->src_port == q->id.dst_port &&
806 pkt->dst_port == q->id.src_port ) {
807 dir = MATCH_REVERSE;
808 break;
809 }
810 }
811 next:
812 prev = q;
813 q = q->next;
814 }
815 if (q == NULL)
816 goto done; /* q = NULL, not found */
817
818 if ( prev != NULL) { /* found and not in front */
819 prev->next = q->next;
820 q->next = ipfw_dyn_v[i];
821 ipfw_dyn_v[i] = q;
822 }
823 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */
824 u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST);
825
826 #define BOTH_SYN (TH_SYN | (TH_SYN << 8))
827 #define BOTH_FIN (TH_FIN | (TH_FIN << 8))
828 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8);
829 switch (q->state) {
830 case TH_SYN: /* opening */
831 q->expire = time_second + dyn_syn_lifetime;
832 break;
833
834 case BOTH_SYN: /* move to established */
835 case BOTH_SYN | TH_FIN : /* one side tries to close */
836 case BOTH_SYN | (TH_FIN << 8) :
837 if (tcp) {
838 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
839 uint32_t ack = ntohl(tcp->th_ack);
840 if (dir == MATCH_FORWARD) {
841 if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd))
842 q->ack_fwd = ack;
843 else { /* ignore out-of-sequence */
844 break;
845 }
846 } else {
847 if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev))
848 q->ack_rev = ack;
849 else { /* ignore out-of-sequence */
850 break;
851 }
852 }
853 }
854 q->expire = time_second + dyn_ack_lifetime;
855 break;
856
857 case BOTH_SYN | BOTH_FIN: /* both sides closed */
858 if (dyn_fin_lifetime >= dyn_keepalive_period)
859 dyn_fin_lifetime = dyn_keepalive_period - 1;
860 q->expire = time_second + dyn_fin_lifetime;
861 break;
862
863 default:
864 #if 0
865 /*
866 * reset or some invalid combination, but can also
867 * occur if we use keep-state the wrong way.
868 */
869 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
870 kprintf("invalid state: 0x%x\n", q->state);
871 #endif
872 if (dyn_rst_lifetime >= dyn_keepalive_period)
873 dyn_rst_lifetime = dyn_keepalive_period - 1;
874 q->expire = time_second + dyn_rst_lifetime;
875 break;
876 }
877 } else if (pkt->proto == IPPROTO_UDP) {
878 q->expire = time_second + dyn_udp_lifetime;
879 } else {
880 /* other protocols */
881 q->expire = time_second + dyn_short_lifetime;
882 }
883 done:
884 if (match_direction)
885 *match_direction = dir;
886 return q;
887 }
888
889 static void
890 realloc_dynamic_table(void)
891 {
892 /*
893 * Try reallocation, make sure we have a power of 2 and do
894 * not allow more than 64k entries. In case of overflow,
895 * default to 1024.
896 */
897
898 if (dyn_buckets > 65536)
899 dyn_buckets = 1024;
900 if ((dyn_buckets & (dyn_buckets-1)) != 0) { /* not a power of 2 */
901 dyn_buckets = curr_dyn_buckets; /* reset */
902 return;
903 }
904 curr_dyn_buckets = dyn_buckets;
905 if (ipfw_dyn_v != NULL)
906 kfree(ipfw_dyn_v, M_IPFW);
907 for (;;) {
908 ipfw_dyn_v = kmalloc(curr_dyn_buckets * sizeof(ipfw_dyn_rule *),
909 M_IPFW, M_INTWAIT | M_NULLOK | M_ZERO);
910 if (ipfw_dyn_v != NULL || curr_dyn_buckets <= 2)
911 break;
912 curr_dyn_buckets /= 2;
913 }
914 }
915
916 /**
917 * Install state of type 'type' for a dynamic session.
918 * The hash table contains two type of rules:
919 * - regular rules (O_KEEP_STATE)
920 * - rules for sessions with limited number of sess per user
921 * (O_LIMIT). When they are created, the parent is
922 * increased by 1, and decreased on delete. In this case,
923 * the third parameter is the parent rule and not the chain.
924 * - "parent" rules for the above (O_LIMIT_PARENT).
925 */
926 static ipfw_dyn_rule *
927 add_dyn_rule(struct ipfw_flow_id *id, uint8_t dyn_type, struct ip_fw *rule)
928 {
929 ipfw_dyn_rule *r;
930 int i;
931
932 if (ipfw_dyn_v == NULL ||
933 (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) {
934 realloc_dynamic_table();
935 if (ipfw_dyn_v == NULL)
936 return NULL; /* failed ! */
937 }
938 i = hash_packet(id);
939
940 r = kmalloc(sizeof *r, M_IPFW, M_INTWAIT | M_NULLOK | M_ZERO);
941 if (r == NULL) {
942 kprintf ("sorry cannot allocate state\n");
943 return NULL;
944 }
945
946 /* increase refcount on parent, and set pointer */
947 if (dyn_type == O_LIMIT) {
948 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule;
949 if ( parent->dyn_type != O_LIMIT_PARENT)
950 panic("invalid parent");
951 parent->count++;
952 r->parent = parent;
953 rule = parent->rule;
954 }
955
956 r->id = *id;
957 r->expire = time_second + dyn_syn_lifetime;
958 r->rule = rule;
959 r->dyn_type = dyn_type;
960 r->pcnt = r->bcnt = 0;
961 r->count = 0;
962
963 r->bucket = i;
964 r->next = ipfw_dyn_v[i];
965 ipfw_dyn_v[i] = r;
966 dyn_count++;
967 DEB(kprintf("-- add dyn entry ty %d 0x%08x %d -> 0x%08x %d, total %d\n",
968 dyn_type,
969 (r->id.src_ip), (r->id.src_port),
970 (r->id.dst_ip), (r->id.dst_port),
971 dyn_count ); )
972 return r;
973 }
974
975 /**
976 * lookup dynamic parent rule using pkt and rule as search keys.
977 * If the lookup fails, then install one.
978 */
979 static ipfw_dyn_rule *
980 lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule)
981 {
982 ipfw_dyn_rule *q;
983 int i;
984
985 if (ipfw_dyn_v) {
986 i = hash_packet( pkt );
987 for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next)
988 if (q->dyn_type == O_LIMIT_PARENT &&
989 rule== q->rule &&
990 pkt->proto == q->id.proto &&
991 pkt->src_ip == q->id.src_ip &&
992 pkt->dst_ip == q->id.dst_ip &&
993 pkt->src_port == q->id.src_port &&
994 pkt->dst_port == q->id.dst_port) {
995 q->expire = time_second + dyn_short_lifetime;
996 DEB(kprintf("lookup_dyn_parent found 0x%p\n",q);)
997 return q;
998 }
999 }
1000 return add_dyn_rule(pkt, O_LIMIT_PARENT, rule);
1001 }
1002
1003 /**
1004 * Install dynamic state for rule type cmd->o.opcode
1005 *
1006 * Returns 1 (failure) if state is not installed because of errors or because
1007 * session limitations are enforced.
1008 */
1009 static int
1010 install_state(struct ip_fw *rule, ipfw_insn_limit *cmd,
1011 struct ip_fw_args *args)
1012 {
1013 static int last_log;
1014
1015 ipfw_dyn_rule *q;
1016
1017 DEB(kprintf("-- install state type %d 0x%08x %u -> 0x%08x %u\n",
1018 cmd->o.opcode,
1019 (args->f_id.src_ip), (args->f_id.src_port),
1020 (args->f_id.dst_ip), (args->f_id.dst_port) );)
1021
1022 q = lookup_dyn_rule(&args->f_id, NULL, NULL);
1023
1024 if (q != NULL) { /* should never occur */
1025 if (last_log != time_second) {
1026 last_log = time_second;
1027 kprintf(" install_state: entry already present, done\n");
1028 }
1029 return 0;
1030 }
1031
1032 if (dyn_count >= dyn_max)
1033 /*
1034 * Run out of slots, try to remove any expired rule.
1035 */
1036 remove_dyn_rule(NULL, (ipfw_dyn_rule *)1);
1037
1038 if (dyn_count >= dyn_max) {
1039 if (last_log != time_second) {
1040 last_log = time_second;
1041 kprintf("install_state: Too many dynamic rules\n");
1042 }
1043 return 1; /* cannot install, notify caller */
1044 }
1045
1046 switch (cmd->o.opcode) {
1047 case O_KEEP_STATE: /* bidir rule */
1048 add_dyn_rule(&args->f_id, O_KEEP_STATE, rule);
1049 break;
1050
1051 case O_LIMIT: /* limit number of sessions */
1052 {
1053 uint16_t limit_mask = cmd->limit_mask;
1054 struct ipfw_flow_id id;
1055 ipfw_dyn_rule *parent;
1056
1057 DEB(kprintf("installing dyn-limit rule %d\n", cmd->conn_limit);)
1058
1059 id.dst_ip = id.src_ip = 0;
1060 id.dst_port = id.src_port = 0;
1061 id.proto = args->f_id.proto;
1062
1063 if (limit_mask & DYN_SRC_ADDR)
1064 id.src_ip = args->f_id.src_ip;
1065 if (limit_mask & DYN_DST_ADDR)
1066 id.dst_ip = args->f_id.dst_ip;
1067 if (limit_mask & DYN_SRC_PORT)
1068 id.src_port = args->f_id.src_port;
1069 if (limit_mask & DYN_DST_PORT)
1070 id.dst_port = args->f_id.dst_port;
1071 parent = lookup_dyn_parent(&id, rule);
1072 if (parent == NULL) {
1073 kprintf("add parent failed\n");
1074 return 1;
1075 }
1076 if (parent->count >= cmd->conn_limit) {
1077 /*
1078 * See if we can remove some expired rule.
1079 */
1080 remove_dyn_rule(rule, parent);
1081 if (parent->count >= cmd->conn_limit) {
1082 if (fw_verbose && last_log != time_second) {
1083 last_log = time_second;
1084 log(LOG_SECURITY | LOG_DEBUG,
1085 "drop session, too many entries\n");
1086 }
1087 return 1;
1088 }
1089 }
1090 add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent);
1091 }
1092 break;
1093 default:
1094 kprintf("unknown dynamic rule type %u\n", cmd->o.opcode);
1095 return 1;
1096 }
1097 lookup_dyn_rule(&args->f_id, NULL, NULL); /* XXX just set lifetime */
1098 return 0;
1099 }
1100
1101 /*
1102 * Transmit a TCP packet, containing either a RST or a keepalive.
1103 * When flags & TH_RST, we are sending a RST packet, because of a
1104 * "reset" action matched the packet.
1105 * Otherwise we are sending a keepalive, and flags & TH_
1106 */
1107 static void
1108 send_pkt(struct ipfw_flow_id *id, uint32_t seq, uint32_t ack, int flags)
1109 {
1110 struct mbuf *m;
1111 struct ip *ip;
1112 struct tcphdr *tcp;
1113 struct route sro; /* fake route */
1114
1115 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1116 if (m == 0)
1117 return;
1118 m->m_pkthdr.rcvif = NULL;
1119 m->m_pkthdr.len = m->m_len = sizeof(struct ip) + sizeof(struct tcphdr);
1120 m->m_data += max_linkhdr;
1121
1122 ip = mtod(m, struct ip *);
1123 bzero(ip, m->m_len);
1124 tcp = (struct tcphdr *)(ip + 1); /* no IP options */
1125 ip->ip_p = IPPROTO_TCP;
1126 tcp->th_off = 5;
1127
1128 /*
1129 * Assume we are sending a RST (or a keepalive in the reverse
1130 * direction), swap src and destination addresses and ports.
1131 */
1132 ip->ip_src.s_addr = htonl(id->dst_ip);
1133 ip->ip_dst.s_addr = htonl(id->src_ip);
1134 tcp->th_sport = htons(id->dst_port);
1135 tcp->th_dport = htons(id->src_port);
1136 if (flags & TH_RST) { /* we are sending a RST */
1137 if (flags & TH_ACK) {
1138 tcp->th_seq = htonl(ack);
1139 tcp->th_ack = htonl(0);
1140 tcp->th_flags = TH_RST;
1141 } else {
1142 if (flags & TH_SYN)
1143 seq++;
1144 tcp->th_seq = htonl(0);
1145 tcp->th_ack = htonl(seq);
1146 tcp->th_flags = TH_RST | TH_ACK;
1147 }
1148 } else {
1149 /*
1150 * We are sending a keepalive. flags & TH_SYN determines
1151 * the direction, forward if set, reverse if clear.
1152 * NOTE: seq and ack are always assumed to be correct
1153 * as set by the caller. This may be confusing...
1154 */
1155 if (flags & TH_SYN) {
1156 /*
1157 * we have to rewrite the correct addresses!
1158 */
1159 ip->ip_dst.s_addr = htonl(id->dst_ip);
1160 ip->ip_src.s_addr = htonl(id->src_ip);
1161 tcp->th_dport = htons(id->dst_port);
1162 tcp->th_sport = htons(id->src_port);
1163 }
1164 tcp->th_seq = htonl(seq);
1165 tcp->th_ack = htonl(ack);
1166 tcp->th_flags = TH_ACK;
1167 }
1168
1169 /*
1170 * set ip_len to the payload size so we can compute
1171 * the tcp checksum on the pseudoheader
1172 * XXX check this, could save a couple of words ?
1173 */
1174 ip->ip_len = htons(sizeof(struct tcphdr));
1175 tcp->th_sum = in_cksum(m, m->m_pkthdr.len);
1176
1177 /*
1178 * now fill fields left out earlier
1179 */
1180 ip->ip_ttl = ip_defttl;
1181 ip->ip_len = m->m_pkthdr.len;
1182
1183 bzero(&sro, sizeof(sro));
1184 ip_rtaddr(ip->ip_dst, &sro);
1185
1186 m->m_pkthdr.fw_flags |= IPFW_MBUF_GENERATED;
1187 ip_output(m, NULL, &sro, 0, NULL, NULL);
1188 if (sro.ro_rt)
1189 RTFREE(sro.ro_rt);
1190 }
1191
1192 /*
1193 * sends a reject message, consuming the mbuf passed as an argument.
1194 */
1195 static void
1196 send_reject(struct ip_fw_args *args, int code, int offset, int ip_len)
1197 {
1198
1199 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */
1200 /* We need the IP header in host order for icmp_error(). */
1201 if (args->eh != NULL) {
1202 struct ip *ip = mtod(args->m, struct ip *);
1203 ip->ip_len = ntohs(ip->ip_len);
1204 ip->ip_off = ntohs(ip->ip_off);
1205 }
1206 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0);
1207 } else if (offset == 0 && args->f_id.proto == IPPROTO_TCP) {
1208 struct tcphdr *const tcp =
1209 L3HDR(struct tcphdr, mtod(args->m, struct ip *));
1210 if ( (tcp->th_flags & TH_RST) == 0)
1211 send_pkt(&(args->f_id), ntohl(tcp->th_seq),
1212 ntohl(tcp->th_ack),
1213 tcp->th_flags | TH_RST);
1214 m_freem(args->m);
1215 } else
1216 m_freem(args->m);
1217 args->m = NULL;
1218 }
1219
1220 /**
1221 *
1222 * Given an ip_fw *, lookup_next_rule will return a pointer
1223 * to the next rule, which can be either the jump
1224 * target (for skipto instructions) or the next one in the list (in
1225 * all other cases including a missing jump target).
1226 * The result is also written in the "next_rule" field of the rule.
1227 * Backward jumps are not allowed, so start looking from the next
1228 * rule...
1229 *
1230 * This never returns NULL -- in case we do not have an exact match,
1231 * the next rule is returned. When the ruleset is changed,
1232 * pointers are flushed so we are always correct.
1233 */
1234
1235 static struct ip_fw *
1236 lookup_next_rule(struct ip_fw *me)
1237 {
1238 struct ip_fw *rule = NULL;
1239 ipfw_insn *cmd;
1240
1241 /* look for action, in case it is a skipto */
1242 cmd = ACTION_PTR(me);
1243 if (cmd->opcode == O_LOG)
1244 cmd += F_LEN(cmd);
1245 if ( cmd->opcode == O_SKIPTO )
1246 for (rule = me->next; rule ; rule = rule->next)
1247 if (rule->rulenum >= cmd->arg1)
1248 break;
1249 if (rule == NULL) /* failure or not a skipto */
1250 rule = me->next;
1251 me->next_rule = rule;
1252 return rule;
1253 }
1254
1255 /*
1256 * The main check routine for the firewall.
1257 *
1258 * All arguments are in args so we can modify them and return them
1259 * back to the caller.
1260 *
1261 * Parameters:
1262 *
1263 * args->m (in/out) The packet; we set to NULL when/if we nuke it.
1264 * Starts with the IP header.
1265 * args->eh (in) Mac header if present, or NULL for layer3 packet.
1266 * args->oif Outgoing interface, or NULL if packet is incoming.
1267 * The incoming interface is in the mbuf. (in)
1268 *
1269 * args->rule Pointer to the last matching rule (in/out)
1270 * args->next_hop Socket we are forwarding to (out).
1271 * args->f_id Addresses grabbed from the packet (out)
1272 *
1273 * Return value:
1274 *
1275 * IP_FW_PORT_DENY_FLAG the packet must be dropped.
1276 * 0 The packet is to be accepted and routed normally OR
1277 * the packet was denied/rejected and has been dropped;
1278 * in the latter case, *m is equal to NULL upon return.
1279 * port Divert the packet to port, with these caveats:
1280 *
1281 * - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead
1282 * of diverting it (ie, 'ipfw tee').
1283 *
1284 * - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower
1285 * 16 bits as a dummynet pipe number instead of diverting
1286 */
1287
1288 static int
1289 ipfw_chk(struct ip_fw_args *args)
1290 {
1291 /*
1292 * Local variables hold state during the processing of a packet.
1293 *
1294 * IMPORTANT NOTE: to speed up the processing of rules, there
1295 * are some assumption on the values of the variables, which
1296 * are documented here. Should you change them, please check
1297 * the implementation of the various instructions to make sure
1298 * that they still work.
1299 *
1300 * args->eh The MAC header. It is non-null for a layer2
1301 * packet, it is NULL for a layer-3 packet.
1302 *
1303 * m | args->m Pointer to the mbuf, as received from the caller.
1304 * It may change if ipfw_chk() does an m_pullup, or if it
1305 * consumes the packet because it calls send_reject().
1306 * XXX This has to change, so that ipfw_chk() never modifies
1307 * or consumes the buffer.
1308 * ip is simply an alias of the value of m, and it is kept
1309 * in sync with it (the packet is supposed to start with
1310 * the ip header).
1311 */
1312 struct mbuf *m = args->m;
1313 struct ip *ip = mtod(m, struct ip *);
1314
1315 /*
1316 * oif | args->oif If NULL, ipfw_chk has been called on the
1317 * inbound path (ether_input, ip_input).
1318 * If non-NULL, ipfw_chk has been called on the outbound path
1319 * (ether_output, ip_output).
1320 */
1321 struct ifnet *oif = args->oif;
1322
1323 struct ip_fw *f = NULL; /* matching rule */
1324 int retval = 0;
1325 struct m_tag *mtag;
1326
1327 /*
1328 * hlen The length of the IPv4 header.
1329 * hlen >0 means we have an IPv4 packet.
1330 */
1331 u_int hlen = 0; /* hlen >0 means we have an IP pkt */
1332
1333 /*
1334 * offset The offset of a fragment. offset != 0 means that
1335 * we have a fragment at this offset of an IPv4 packet.
1336 * offset == 0 means that (if this is an IPv4 packet)
1337 * this is the first or only fragment.
1338 */
1339 u_short offset = 0;
1340
1341 /*
1342 * Local copies of addresses. They are only valid if we have
1343 * an IP packet.
1344 *
1345 * proto The protocol. Set to 0 for non-ip packets,
1346 * or to the protocol read from the packet otherwise.
1347 * proto != 0 means that we have an IPv4 packet.
1348 *
1349 * src_port, dst_port port numbers, in HOST format. Only
1350 * valid for TCP and UDP packets.
1351 *
1352 * src_ip, dst_ip ip addresses, in NETWORK format.
1353 * Only valid for IPv4 packets.
1354 */
1355 uint8_t proto;
1356 uint16_t src_port = 0, dst_port = 0; /* NOTE: host format */
1357 struct in_addr src_ip, dst_ip; /* NOTE: network format */
1358 uint16_t ip_len = 0;
1359 int dyn_dir = MATCH_UNKNOWN;
1360 ipfw_dyn_rule *q = NULL;
1361
1362 if (m->m_pkthdr.fw_flags & IPFW_MBUF_GENERATED)
1363 return 0; /* accept */
1364 /*
1365 * dyn_dir = MATCH_UNKNOWN when rules unchecked,
1366 * MATCH_NONE when checked and not matched (q = NULL),
1367 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL)
1368 */
1369
1370 if (args->eh == NULL || /* layer 3 packet */
1371 (m->m_pkthdr.len >= sizeof(struct ip) &&
1372 ntohs(args->eh->ether_type) == ETHERTYPE_IP))
1373 hlen = ip->ip_hl << 2;
1374
1375 /*
1376 * Collect parameters into local variables for faster matching.
1377 */
1378 if (hlen == 0) { /* do not grab addresses for non-ip pkts */
1379 proto = args->f_id.proto = 0; /* mark f_id invalid */
1380 goto after_ip_checks;
1381 }
1382
1383 proto = args->f_id.proto = ip->ip_p;
1384 src_ip = ip->ip_src;
1385 dst_ip = ip->ip_dst;
1386 if (args->eh != NULL) { /* layer 2 packets are as on the wire */
1387 offset = ntohs(ip->ip_off) & IP_OFFMASK;
1388 ip_len = ntohs(ip->ip_len);
1389 } else {
1390 offset = ip->ip_off & IP_OFFMASK;
1391 ip_len = ip->ip_len;
1392 }
1393
1394 #define PULLUP_TO(len) \
1395 do { \
1396 if (m->m_len < (len)) { \
1397 args->m = m = m_pullup(m, (len));\
1398 if (m == NULL) \
1399 goto pullup_failed; \
1400 ip = mtod(m, struct ip *); \
1401 } \
1402 } while (0)
1403
1404 if (offset == 0) {
1405 switch (proto) {
1406 case IPPROTO_TCP:
1407 {
1408 struct tcphdr *tcp;
1409
1410 PULLUP_TO(hlen + sizeof(struct tcphdr));
1411 tcp = L3HDR(struct tcphdr, ip);
1412 dst_port = tcp->th_dport;
1413 src_port = tcp->th_sport;
1414 args->f_id.flags = tcp->th_flags;
1415 }
1416 break;
1417
1418 case IPPROTO_UDP:
1419 {
1420 struct udphdr *udp;
1421
1422 PULLUP_TO(hlen + sizeof(struct udphdr));
1423 udp = L3HDR(struct udphdr, ip);
1424 dst_port = udp->uh_dport;
1425 src_port = udp->uh_sport;
1426 }
1427 break;
1428
1429 case IPPROTO_ICMP:
1430 PULLUP_TO(hlen + 4); /* type, code and checksum. */
1431 args->f_id.flags = L3HDR(struct icmp, ip)->icmp_type;
1432 break;
1433
1434 default:
1435 break;
1436 }
1437 }
1438
1439 #undef PULLUP_TO
1440
1441 args->f_id.src_ip = ntohl(src_ip.s_addr);
1442 args->f_id.dst_ip = ntohl(dst_ip.s_addr);
1443 args->f_id.src_port = src_port = ntohs(src_port);
1444 args->f_id.dst_port = dst_port = ntohs(dst_port);
1445
1446 after_ip_checks:
1447 if (args->rule) {
1448 /*
1449 * Packet has already been tagged. Look for the next rule
1450 * to restart processing.
1451 *
1452 * If fw_one_pass != 0 then just accept it.
1453 * XXX should not happen here, but optimized out in
1454 * the caller.
1455 */
1456 if (fw_one_pass)
1457 return 0;
1458
1459 /* This rule was deleted */
1460 if (args->rule->rule_flags & IPFW_RULE_F_INVALID)
1461 return IP_FW_PORT_DENY_FLAG;
1462
1463 f = args->rule->next_rule;
1464 if (f == NULL)
1465 f = lookup_next_rule(args->rule);
1466 } else {
1467 /*
1468 * Find the starting rule. It can be either the first
1469 * one, or the one after divert_rule if asked so.
1470 */
1471 int skipto;
1472
1473 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
1474 if (mtag != NULL)
1475 skipto = *(uint16_t *)m_tag_data(mtag);
1476 else
1477 skipto = 0;
1478
1479 f = layer3_chain;
1480 if (args->eh == NULL && skipto != 0) {
1481 if (skipto >= IPFW_DEFAULT_RULE)
1482 return(IP_FW_PORT_DENY_FLAG); /* invalid */
1483 while (f && f->rulenum <= skipto)
1484 f = f->next;
1485 if (f == NULL) /* drop packet */
1486 return(IP_FW_PORT_DENY_FLAG);
1487 }
1488 }
1489 if ((mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL)) != NULL)
1490 m_tag_delete(m, mtag);
1491
1492 /*
1493 * Now scan the rules, and parse microinstructions for each rule.
1494 */
1495 for (; f; f = f->next) {
1496 int l, cmdlen;
1497 ipfw_insn *cmd;
1498 int skip_or; /* skip rest of OR block */
1499
1500 again:
1501 if (set_disable & (1 << f->set))
1502 continue;
1503
1504 skip_or = 0;
1505 for (l = f->cmd_len, cmd = f->cmd; l > 0;
1506 l -= cmdlen, cmd += cmdlen) {
1507 int match;
1508
1509 /*
1510 * check_body is a jump target used when we find a
1511 * CHECK_STATE, and need to jump to the body of
1512 * the target rule.
1513 */
1514
1515 check_body:
1516 cmdlen = F_LEN(cmd);
1517 /*
1518 * An OR block (insn_1 || .. || insn_n) has the
1519 * F_OR bit set in all but the last instruction.
1520 * The first match will set "skip_or", and cause
1521 * the following instructions to be skipped until
1522 * past the one with the F_OR bit clear.
1523 */
1524 if (skip_or) { /* skip this instruction */
1525 if ((cmd->len & F_OR) == 0)
1526 skip_or = 0; /* next one is good */
1527 continue;
1528 }
1529 match = 0; /* set to 1 if we succeed */
1530
1531 switch (cmd->opcode) {
1532 /*
1533 * The first set of opcodes compares the packet's
1534 * fields with some pattern, setting 'match' if a
1535 * match is found. At the end of the loop there is
1536 * logic to deal with F_NOT and F_OR flags associated
1537 * with the opcode.
1538 */
1539 case O_NOP:
1540 match = 1;
1541 break;
1542
1543 case O_FORWARD_MAC:
1544 kprintf("ipfw: opcode %d unimplemented\n",
1545 cmd->opcode);
1546 break;
1547
1548 case O_GID:
1549 case O_UID:
1550 /*
1551 * We only check offset == 0 && proto != 0,
1552 * as this ensures that we have an IPv4
1553 * packet with the ports info.
1554 */
1555 if (offset!=0)
1556 break;
1557 {
1558 struct inpcbinfo *pi;
1559 int wildcard;
1560 struct inpcb *pcb;
1561
1562 if (proto == IPPROTO_TCP) {
1563 wildcard = 0;
1564 pi = &tcbinfo[mycpu->gd_cpuid];
1565 } else if (proto == IPPROTO_UDP) {
1566 wildcard = 1;
1567 pi = &udbinfo;
1568 } else
1569 break;
1570
1571 pcb = (oif) ?
1572 in_pcblookup_hash(pi,
1573 dst_ip, htons(dst_port),
1574 src_ip, htons(src_port),
1575 wildcard, oif) :
1576 in_pcblookup_hash(pi,
1577 src_ip, htons(src_port),
1578 dst_ip, htons(dst_port),
1579 wildcard, NULL);
1580
1581 if (pcb == NULL || pcb->inp_socket == NULL)
1582 break;
1583
1584 if (cmd->opcode == O_UID) {
1585 #define socheckuid(a,b) ((a)->so_cred->cr_uid != (b))
1586 match =
1587 !socheckuid(pcb->inp_socket,
1588 (uid_t)((ipfw_insn_u32 *)cmd)->d[0]);
1589 #undef socheckuid
1590 } else {
1591 match = groupmember(
1592 (uid_t)((ipfw_insn_u32 *)cmd)->d[0],
1593 pcb->inp_socket->so_cred);
1594 }
1595 }
1596 break;
1597
1598 case O_RECV:
1599 match = iface_match(m->m_pkthdr.rcvif,
1600 (ipfw_insn_if *)cmd);
1601 break;
1602
1603 case O_XMIT:
1604 match = iface_match(oif, (ipfw_insn_if *)cmd);
1605 break;
1606
1607 case O_VIA:
1608 match = iface_match(oif ? oif :
1609 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd);
1610 break;
1611
1612 case O_MACADDR2:
1613 if (args->eh != NULL) { /* have MAC header */
1614 uint32_t *want = (uint32_t *)
1615 ((ipfw_insn_mac *)cmd)->addr;
1616 uint32_t *mask = (uint32_t *)
1617 ((ipfw_insn_mac *)cmd)->mask;
1618 uint32_t *hdr = (uint32_t *)args->eh;
1619
1620 match =
1621 (want[0] == (hdr[0] & mask[0]) &&
1622 want[1] == (hdr[1] & mask[1]) &&
1623 want[2] == (hdr[2] & mask[2]));
1624 }
1625 break;
1626
1627 case O_MAC_TYPE:
1628 if (args->eh != NULL) {
1629 uint16_t t =
1630 ntohs(args->eh->ether_type);
1631 uint16_t *p =
1632 ((ipfw_insn_u16 *)cmd)->ports;
1633 int i;
1634
1635 /* Special vlan handling */
1636 if (m->m_flags & M_VLANTAG)
1637 t = ETHERTYPE_VLAN;
1638
1639 for (i = cmdlen - 1; !match && i > 0;
1640 i--, p += 2) {
1641 match =
1642 (t >= p[0] && t <= p[1]);
1643 }
1644 }
1645 break;
1646
1647 case O_FRAG:
1648 match = (hlen > 0 && offset != 0);
1649 break;
1650
1651 case O_IN: /* "out" is "not in" */
1652 match = (oif == NULL);
1653 break;
1654
1655 case O_LAYER2:
1656 match = (args->eh != NULL);
1657 break;
1658
1659 case O_PROTO:
1660 /*
1661 * We do not allow an arg of 0 so the
1662 * check of "proto" only suffices.
1663 */
1664 match = (proto == cmd->arg1);
1665 break;
1666
1667 case O_IP_SRC:
1668 match = (hlen > 0 &&
1669 ((ipfw_insn_ip *)cmd)->addr.s_addr ==
1670 src_ip.s_addr);
1671 break;
1672
1673 case O_IP_SRC_MASK:
1674 match = (hlen > 0 &&
1675 ((ipfw_insn_ip *)cmd)->addr.s_addr ==
1676 (src_ip.s_addr &
1677 ((ipfw_insn_ip *)cmd)->mask.s_addr));
1678 break;
1679
1680 case O_IP_SRC_ME:
1681 if (hlen > 0) {
1682 struct ifnet *tif;
1683
1684 tif = INADDR_TO_IFP(&src_ip);
1685 match = (tif != NULL);
1686 }
1687 break;
1688
1689 case O_IP_DST_SET:
1690 case O_IP_SRC_SET:
1691 if (hlen > 0) {
1692 uint32_t *d = (uint32_t *)(cmd+1);
1693 uint32_t addr =
1694 cmd->opcode == O_IP_DST_SET ?
1695 args->f_id.dst_ip :
1696 args->f_id.src_ip;
1697
1698 if (addr < d[0])
1699 break;
1700 addr -= d[0]; /* subtract base */
1701 match =
1702 (addr < cmd->arg1) &&
1703 (d[1 + (addr >> 5)] &
1704 (1 << (addr & 0x1f)));
1705 }
1706 break;
1707
1708 case O_IP_DST:
1709 match = (hlen > 0 &&
1710 ((ipfw_insn_ip *)cmd)->addr.s_addr ==
1711 dst_ip.s_addr);
1712 break;
1713
1714 case O_IP_DST_MASK:
1715 match = (hlen > 0) &&
1716 (((ipfw_insn_ip *)cmd)->addr.s_addr ==
1717 (dst_ip.s_addr &
1718 ((ipfw_insn_ip *)cmd)->mask.s_addr));
1719 break;
1720
1721 case O_IP_DST_ME:
1722 if (hlen > 0) {
1723 struct ifnet *tif;
1724
1725 tif = INADDR_TO_IFP(&dst_ip);
1726 match = (tif != NULL);
1727 }
1728 break;
1729
1730 case O_IP_SRCPORT:
1731 case O_IP_DSTPORT:
1732 /*
1733 * offset == 0 && proto != 0 is enough
1734 * to guarantee that we have an IPv4
1735 * packet with port info.
1736 */
1737 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP)
1738 && offset == 0) {
1739 uint16_t x =
1740 (cmd->opcode == O_IP_SRCPORT) ?
1741 src_port : dst_port ;
1742 uint16_t *p =
1743 ((ipfw_insn_u16 *)cmd)->ports;
1744 int i;
1745
1746 for (i = cmdlen - 1; !match && i > 0;
1747 i--, p += 2) {
1748 match =
1749 (x >= p[0] && x <= p[1]);
1750 }
1751 }
1752 break;
1753
1754 case O_ICMPTYPE:
1755 match = (offset == 0 && proto==IPPROTO_ICMP &&
1756 icmptype_match(ip, (ipfw_insn_u32 *)cmd));
1757 break;
1758
1759 case O_IPOPT:
1760 match = (hlen > 0 && ipopts_match(ip, cmd));
1761 break;
1762
1763 case O_IPVER:
1764 match = (hlen > 0 && cmd->arg1 == ip->ip_v);
1765 break;
1766
1767 case O_IPTTL:
1768 match = (hlen > 0 && cmd->arg1 == ip->ip_ttl);
1769 break;
1770
1771 case O_IPID:
1772 match = (hlen > 0 &&
1773 cmd->arg1 == ntohs(ip->ip_id));
1774 break;
1775
1776 case O_IPLEN:
1777 match = (hlen > 0 && cmd->arg1 == ip_len);
1778 break;
1779
1780 case O_IPPRECEDENCE:
1781 match = (hlen > 0 &&
1782 (cmd->arg1 == (ip->ip_tos & 0xe0)));
1783 break;
1784
1785 case O_IPTOS:
1786 match = (hlen > 0 &&
1787 flags_match(cmd, ip->ip_tos));
1788 break;
1789
1790 case O_TCPFLAGS:
1791 match = (proto == IPPROTO_TCP && offset == 0 &&
1792 flags_match(cmd,
1793 L3HDR(struct tcphdr,ip)->th_flags));
1794 break;
1795
1796 case O_TCPOPTS:
1797 match = (proto == IPPROTO_TCP && offset == 0 &&
1798 tcpopts_match(ip, cmd));
1799 break;
1800
1801 case O_TCPSEQ:
1802 match = (proto == IPPROTO_TCP && offset == 0 &&
1803 ((ipfw_insn_u32 *)cmd)->d[0] ==
1804 L3HDR(struct tcphdr,ip)->th_seq);
1805 break;
1806
1807 case O_TCPACK:
1808 match = (proto == IPPROTO_TCP && offset == 0 &&
1809 ((ipfw_insn_u32 *)cmd)->d[0] ==
1810 L3HDR(struct tcphdr,ip)->th_ack);
1811 break;
1812
1813 case O_TCPWIN:
1814 match = (proto == IPPROTO_TCP && offset == 0 &&
1815 cmd->arg1 ==
1816 L3HDR(struct tcphdr,ip)->th_win);
1817 break;
1818
1819 case O_ESTAB:
1820 /* reject packets which have SYN only */
1821 /* XXX should i also check for TH_ACK ? */
1822 match = (proto == IPPROTO_TCP && offset == 0 &&
1823 (L3HDR(struct tcphdr,ip)->th_flags &
1824 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN);
1825 break;
1826
1827 case O_LOG:
1828 if (fw_verbose)
1829 ipfw_log(f, hlen, args->eh, m, oif);
1830 match = 1;
1831 break;
1832
1833 case O_PROB:
1834 match = (krandom() <
1835 ((ipfw_insn_u32 *)cmd)->d[0]);
1836 break;
1837
1838 /*
1839 * The second set of opcodes represents 'actions',
1840 * i.e. the terminal part of a rule once the packet
1841 * matches all previous patterns.
1842 * Typically there is only one action for each rule,
1843 * and the opcode is stored at the end of the rule
1844 * (but there are exceptions -- see below).
1845 *
1846 * In general, here we set retval and terminate the
1847 * outer loop (would be a 'break 3' in some language,
1848 * but we need to do a 'goto done').
1849 *
1850 * Exceptions:
1851 * O_COUNT and O_SKIPTO actions:
1852 * instead of terminating, we jump to the next rule
1853 * ('goto next_rule', equivalent to a 'break 2'),
1854 * or to the SKIPTO target ('goto again' after
1855 * having set f, cmd and l), respectively.
1856 *
1857 * O_LIMIT and O_KEEP_STATE: these opcodes are
1858 * not real 'actions', and are stored right
1859 * before the 'action' part of the rule.
1860 * These opcodes try to install an entry in the
1861 * state tables; if successful, we continue with
1862 * the next opcode (match=1; break;), otherwise
1863 * the packet * must be dropped
1864 * ('goto done' after setting retval);
1865 *
1866 * O_PROBE_STATE and O_CHECK_STATE: these opcodes
1867 * cause a lookup of the state table, and a jump
1868 * to the 'action' part of the parent rule
1869 * ('goto check_body') if an entry is found, or
1870 * (CHECK_STATE only) a jump to the next rule if
1871 * the entry is not found ('goto next_rule').
1872 * The result of the lookup is cached to make
1873 * further instances of these opcodes are
1874 * effectively NOPs.
1875 */
1876 case O_LIMIT:
1877 case O_KEEP_STATE:
1878 if (install_state(f,
1879 (ipfw_insn_limit *)cmd, args)) {
1880 retval = IP_FW_PORT_DENY_FLAG;
1881 goto done; /* error/limit violation */
1882 }
1883 match = 1;
1884 break;
1885
1886 case O_PROBE_STATE:
1887 case O_CHECK_STATE:
1888 /*
1889 * dynamic rules are checked at the first
1890 * keep-state or check-state occurrence,
1891 * with the result being stored in dyn_dir.
1892 * The compiler introduces a PROBE_STATE
1893 * instruction for us when we have a
1894 * KEEP_STATE (because PROBE_STATE needs
1895 * to be run first).
1896 */
1897 if (dyn_dir == MATCH_UNKNOWN &&
1898 (q = lookup_dyn_rule(&args->f_id,
1899 &dyn_dir, proto == IPPROTO_TCP ?
1900 L3HDR(struct tcphdr, ip) : NULL))
1901 != NULL) {
1902 /*
1903 * Found dynamic entry, update stats
1904 * and jump to the 'action' part of
1905 * the parent rule.
1906 */
1907 q->pcnt++;
1908 q->bcnt += ip_len;
1909 f = q->rule;
1910 cmd = ACTION_PTR(f);
1911 l = f->cmd_len - f->act_ofs;
1912 goto check_body;
1913 }
1914 /*
1915 * Dynamic entry not found. If CHECK_STATE,
1916 * skip to next rule, if PROBE_STATE just
1917 * ignore and continue with next opcode.
1918 */
1919 if (cmd->opcode == O_CHECK_STATE)
1920 goto next_rule;
1921 match = 1;
1922 break;
1923
1924 case O_ACCEPT:
1925 retval = 0; /* accept */
1926 goto done;
1927
1928 case O_PIPE:
1929 case O_QUEUE:
1930 args->rule = f; /* report matching rule */
1931 retval = cmd->arg1 | IP_FW_PORT_DYNT_FLAG;
1932 goto done;
1933
1934 case O_DIVERT:
1935 case O_TEE:
1936 if (args->eh) /* not on layer 2 */
1937 break;
1938
1939 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT,
1940 sizeof(uint16_t), MB_DONTWAIT);
1941 if (mtag == NULL) {
1942 retval = IP_FW_PORT_DENY_FLAG;
1943 goto done;
1944 }
1945 *(uint16_t *)m_tag_data(mtag) = f->rulenum;
1946 m_tag_prepend(m, mtag);
1947 retval = (cmd->opcode == O_DIVERT) ?
1948 cmd->arg1 :
1949 cmd->arg1 | IP_FW_PORT_TEE_FLAG;
1950 goto done;
1951
1952 case O_COUNT:
1953 case O_SKIPTO:
1954 f->pcnt++; /* update stats */
1955 f->bcnt += ip_len;
1956 f->timestamp = time_second;
1957 if (cmd->opcode == O_COUNT)
1958 goto next_rule;
1959 /* handle skipto */
1960 if (f->next_rule == NULL)
1961 lookup_next_rule(f);
1962 f = f->next_rule;
1963 goto again;
1964
1965 case O_REJECT:
1966 /*
1967 * Drop the packet and send a reject notice
1968 * if the packet is not ICMP (or is an ICMP
1969 * query), and it is not multicast/broadcast.
1970 */
1971 if (hlen > 0 &&
1972 (proto != IPPROTO_ICMP ||
1973 is_icmp_query(ip)) &&
1974 !(m->m_flags & (M_BCAST|M_MCAST)) &&
1975 !IN_MULTICAST(ntohl(dst_ip.s_addr))) {
1976 send_reject(args, cmd->arg1,
1977 offset,ip_len);
1978 m = args->m;
1979 }
1980 /* FALLTHROUGH */
1981 case O_DENY:
1982 retval = IP_FW_PORT_DENY_FLAG;
1983 goto done;
1984
1985 case O_FORWARD_IP:
1986 if (args->eh) /* not valid on layer2 pkts */
1987 break;
1988 if (!q || dyn_dir == MATCH_FORWARD) {
1989 args->next_hop =
1990 &((ipfw_insn_sa *)cmd)->sa;
1991 }
1992 retval = 0;
1993 goto done;
1994
1995 default:
1996 panic("-- unknown opcode %d\n", cmd->opcode);
1997 } /* end of switch() on opcodes */
1998
1999 if (cmd->len & F_NOT)
2000 match = !match;
2001
2002 if (match) {
2003 if (cmd->len & F_OR)
2004 skip_or = 1;
2005 } else {
2006 if (!(cmd->len & F_OR)) /* not an OR block, */
2007 break; /* try next rule */
2008 }
2009
2010 } /* end of inner for, scan opcodes */
2011
2012 next_rule:; /* try next rule */
2013
2014 } /* end of outer for, scan rules */
2015 kprintf("+++ ipfw: ouch!, skip past end of rules, denying packet\n");
2016 return(IP_FW_PORT_DENY_FLAG);
2017
2018 done:
2019 /* Update statistics */
2020 f->pcnt++;
2021 f->bcnt += ip_len;
2022 f->timestamp = time_second;
2023 return retval;
2024
2025 pullup_failed:
2026 if (fw_verbose)
2027 kprintf("pullup failed\n");
2028 return(IP_FW_PORT_DENY_FLAG);
2029 }
2030
2031 static void
2032 ipfw_dummynet_io(struct mbuf *m, int pipe_nr, int dir, struct ip_fw_args *fwa)
2033 {
2034 struct m_tag *mtag;
2035 struct dn_pkt *pkt;
2036 ipfw_insn *cmd;
2037 const struct ipfw_flow_id *id;
2038 struct dn_flow_id *fid;
2039
2040 M_ASSERTPKTHDR(m);
2041
2042 mtag = m_tag_get(PACKET_TAG_DUMMYNET, sizeof(*pkt), MB_DONTWAIT);
2043 if (mtag == NULL) {
2044 m_freem(m);
2045 return;
2046 }
2047 m_tag_prepend(m, mtag);
2048
2049 pkt = m_tag_data(mtag);
2050 bzero(pkt, sizeof(*pkt));
2051
2052 cmd = fwa->rule->cmd + fwa->rule->act_ofs;
2053 if (cmd->opcode == O_LOG)
2054 cmd += F_LEN(cmd);
2055 KASSERT(cmd->opcode == O_PIPE || cmd->opcode == O_QUEUE,
2056 ("Rule is not PIPE or QUEUE, opcode %d\n", cmd->opcode));
2057
2058 pkt->dn_m = m;
2059 pkt->dn_flags = (dir & DN_FLAGS_DIR_MASK);
2060 pkt->ifp = fwa->oif;
2061 pkt->cpuid = mycpu->gd_cpuid;
2062 pkt->pipe_nr = pipe_nr;
2063
2064 id = &fwa->f_id;
2065 fid = &pkt->id;
2066 fid->fid_dst_ip = id->dst_ip;
2067 fid->fid_src_ip = id->src_ip;
2068 fid->fid_dst_port = id->dst_port;
2069 fid->fid_src_port = id->src_port;
2070 fid->fid_proto = id->proto;
2071 fid->fid_flags = id->flags;
2072
2073 ipfw_ref_rule(fwa->rule);
2074 pkt->dn_priv = fwa->rule;
2075 pkt->dn_unref_priv = ipfw_unref_rule;
2076
2077 if (cmd->opcode == O_PIPE)
2078 pkt->dn_flags |= DN_FLAGS_IS_PIPE;
2079
2080 if (dir == DN_TO_IP_OUT) {
2081 /*
2082 * We need to copy *ro because for ICMP pkts (and maybe
2083 * others) the caller passed a pointer into the stack;
2084 * dst might also be a pointer into *ro so it needs to
2085 * be updated.
2086 */
2087 pkt->ro = *(fwa->ro);
2088 if (fwa->ro->ro_rt)
2089 fwa->ro->ro_rt->rt_refcnt++;
2090 if (fwa->dst == (struct sockaddr_in *)&fwa->ro->ro_dst) {
2091 /* 'dst' points into 'ro' */
2092 fwa->dst = (struct sockaddr_in *)&(pkt->ro.ro_dst);
2093 }
2094 pkt->dn_dst = fwa->dst;
2095 pkt->flags = fwa->flags;
2096 }
2097
2098 m->m_pkthdr.fw_flags |= DUMMYNET_MBUF_TAGGED;
2099 ip_dn_queue(m);
2100 }
2101
2102 /*
2103 * When a rule is added/deleted, clear the next_rule pointers in all rules.
2104 * These will be reconstructed on the fly as packets are matched.
2105 * Must be called at splimp().
2106 */
2107 static void
2108 flush_rule_ptrs(void)
2109 {
2110 struct ip_fw *rule;
2111
2112 for (rule = layer3_chain; rule; rule = rule->next)
2113 rule->next_rule = NULL;
2114 }
2115
2116 static __inline void
2117 ipfw_inc_static_count(struct ip_fw *rule)
2118 {
2119 static_count++;
2120 static_ioc_len += IOC_RULESIZE(rule);
2121 }
2122
2123 static __inline void
2124 ipfw_dec_static_count(struct ip_fw *rule)
2125 {
2126 int l = IOC_RULESIZE(rule);
2127
2128 KASSERT(static_count > 0, ("invalid static count %u\n", static_count));
2129 static_count--;
2130
2131 KASSERT(static_ioc_len >= l,
2132 ("invalid static len %u\n", static_ioc_len));
2133 static_ioc_len -= l;
2134 }
2135
2136 static struct ip_fw *
2137 ipfw_create_rule(const struct ipfw_ioc_rule *ioc_rule)
2138 {
2139 struct ip_fw *rule;
2140
2141 rule = kmalloc(RULESIZE(ioc_rule), M_IPFW, M_WAITOK | M_ZERO);
2142
2143 rule->act_ofs = ioc_rule->act_ofs;
2144 rule->cmd_len = ioc_rule->cmd_len;
2145 rule->rulenum = ioc_rule->rulenum;
2146 rule->set = ioc_rule->set;
2147 rule->usr_flags = ioc_rule->usr_flags;
2148
2149 bcopy(ioc_rule->cmd, rule->cmd, rule->cmd_len * 4 /* XXX */);
2150
2151 rule->refcnt = 1;
2152
2153 return rule;
2154 }
2155
2156 /*
2157 * Add a new rule to the list. Copy the rule into a malloc'ed area, then
2158 * possibly create a rule number and add the rule to the list.
2159 * Update the rule_number in the input struct so the caller knows it as well.
2160 */
2161 static int
2162 ipfw_add_rule(struct ip_fw **head, struct ipfw_ioc_rule *ioc_rule)
2163 {
2164 struct ip_fw *rule, *f, *prev;
2165
2166 KKASSERT(*head != NULL);
2167
2168 rule = ipfw_create_rule(ioc_rule);
2169
2170 crit_enter();
2171
2172 /*
2173 * If rulenum is 0, find highest numbered rule before the
2174 * default rule, and add autoinc_step
2175 */
2176 if (autoinc_step < 1)
2177 autoinc_step = 1;
2178 else if (autoinc_step > 1000)
2179 autoinc_step = 1000;
2180 if (rule->rulenum == 0) {
2181 /*
2182 * locate the highest numbered rule before default
2183 */
2184 for (f = *head; f; f = f->next) {
2185 if (f->rulenum == IPFW_DEFAULT_RULE)
2186 break;
2187 rule->rulenum = f->rulenum;
2188 }
2189 if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step)
2190 rule->rulenum += autoinc_step;
2191 ioc_rule->rulenum = rule->rulenum;
2192 }
2193
2194 /*
2195 * Now insert the new rule in the right place in the sorted list.
2196 */
2197 for (prev = NULL, f = *head; f; prev = f, f = f->next) {
2198 if (f->rulenum > rule->rulenum) { /* found the location */
2199 if (prev) {
2200 rule->next = f;
2201 prev->next = rule;
2202 } else { /* head insert */
2203 rule->next = *head;
2204 *head = rule;
2205 }
2206 break;
2207 }
2208 }
2209
2210 flush_rule_ptrs();
2211 ipfw_inc_static_count(rule);
2212
2213 crit_exit();
2214
2215 DEB(kprintf("++ installed rule %d, static count now %d\n",
2216 rule->rulenum, static_count);)
2217 return (0);
2218 }
2219
2220 /**
2221 * Free storage associated with a static rule (including derived
2222 * dynamic rules).
2223 * The caller is in charge of clearing rule pointers to avoid
2224 * dangling pointers.
2225 * @return a pointer to the next entry.
2226 * Arguments are not checked, so they better be correct.
2227 * Must be called at splimp().
2228 */
2229 static struct ip_fw *
2230 delete_rule(struct ip_fw **head, struct ip_fw *prev, struct ip_fw *rule)
2231 {
2232 struct ip_fw *n;
2233
2234 n = rule->next;
2235 remove_dyn_rule(rule, NULL /* force removal */);
2236 if (prev == NULL)
2237 *head = n;
2238 else
2239 prev->next = n;
2240 ipfw_dec_static_count(rule);
2241
2242 /* Mark the rule as invalid */
2243 rule->rule_flags |= IPFW_RULE_F_INVALID;
2244 rule->next_rule = NULL;
2245
2246 /* Try to free this rule */
2247 ipfw_free_rule(rule);
2248
2249 return n;
2250 }
2251
2252 /*
2253 * Deletes all rules from a chain (including the default rule
2254 * if the second argument is set).
2255 * Must be called at splimp().
2256 */
2257 static void
2258 free_chain(struct ip_fw **chain, int kill_default)
2259 {
2260 struct ip_fw *rule;
2261
2262 flush_rule_ptrs(); /* more efficient to do outside the loop */
2263
2264 while ((rule = *chain) != NULL &&
2265 (kill_default || rule->rulenum != IPFW_DEFAULT_RULE))
2266 delete_rule(chain, NULL, rule);
2267
2268 KASSERT(dyn_count == 0, ("%u dyn rule remains\n", dyn_count));
2269
2270 if (kill_default) {
2271 ip_fw_default_rule = NULL; /* Reset default rule */
2272
2273 if (ipfw_dyn_v != NULL) {
2274 /*
2275 * Free dynamic rules(state) hash table
2276 */
2277 kfree(ipfw_dyn_v, M_IPFW);
2278 ipfw_dyn_v = NULL;
2279 }
2280
2281 KASSERT(static_count == 0,
2282 ("%u static rules remains\n", static_count));
2283 KASSERT(static_ioc_len == 0,
2284 ("%u bytes of static rules remains\n", static_ioc_len));
2285 } else {
2286 KASSERT(static_count == 1,
2287 ("%u static rules remains\n", static_count));
2288 KASSERT(static_ioc_len == IOC_RULESIZE(ip_fw_default_rule),
2289 ("%u bytes of static rules remains, should be %u\n",
2290 static_ioc_len, IOC_RULESIZE(ip_fw_default_rule)));
2291 }
2292 }
2293
2294 /**
2295 * Remove all rules with given number, and also do set manipulation.
2296 *
2297 * The argument is an uint32_t. The low 16 bit are the rule or set number,
2298 * the next 8 bits are the new set, the top 8 bits are the command:
2299 *
2300 * 0 delete rules with given number
2301 * 1 delete rules with given set number
2302 * 2 move rules with given number to new set
2303 * 3 move rules with given set number to new set
2304 * 4 swap sets with given numbers
2305 */
2306 static int
2307 del_entry(struct ip_fw **chain, uint32_t arg)
2308 {
2309 struct ip_fw *prev, *rule;
2310 uint16_t rulenum;
2311 uint8_t cmd, new_set;
2312
2313 rulenum = arg & 0xffff;
2314 cmd = (arg >> 24) & 0xff;
2315 new_set = (arg >> 16) & 0xff;
2316
2317 if (cmd > 4)
2318 return EINVAL;
2319 if (new_set > 30)
2320 return EINVAL;
2321 if (cmd == 0 || cmd == 2) {
2322 if (rulenum == IPFW_DEFAULT_RULE)
2323 return EINVAL;
2324 } else {
2325 if (rulenum > 30)
2326 return EINVAL;
2327 }
2328
2329 switch (cmd) {
2330 case 0: /* delete rules with given number */
2331 /*
2332 * locate first rule to delete
2333 */
2334 for (prev = NULL, rule = *chain;
2335 rule && rule->rulenum < rulenum;
2336 prev = rule, rule = rule->next)
2337 ;
2338 if (rule->rulenum != rulenum)
2339 return EINVAL;
2340
2341 crit_enter(); /* no access to rules while removing */
2342 /*
2343 * flush pointers outside the loop, then delete all matching
2344 * rules. prev remains the same throughout the cycle.
2345 */
2346 flush_rule_ptrs();
2347 while (rule && rule->rulenum == rulenum)
2348 rule = delete_rule(chain, prev, rule);
2349 crit_exit();
2350 break;
2351
2352 case 1: /* delete all rules with given set number */
2353 crit_enter();
2354 flush_rule_ptrs();
2355 for (prev = NULL, rule = *chain; rule;) {
2356 if (rule->set == rulenum) {
2357 rule = delete_rule(chain, prev, rule);
2358 } else {
2359 prev = rule;
2360 rule = rule->next;
2361 }
2362 }
2363 crit_exit();
2364 break;
2365
2366 case 2: /* move rules with given number to new set */
2367 crit_enter();
2368 for (rule = *chain; rule; rule = rule->next) {
2369 if (rule->rulenum == rulenum)
2370 rule->set = new_set;
2371 }
2372 crit_exit();
2373 break;
2374
2375 case 3: /* move rules with given set number to new set */
2376 crit_enter();
2377 for (rule = *chain; rule; rule = rule->next) {
2378 if (rule->set == rulenum)
2379 rule->set = new_set;
2380 }
2381 crit_exit();
2382 break;
2383
2384 case 4: /* swap two sets */
2385 crit_enter();
2386 for (rule = *chain; rule; rule = rule->next) {
2387 if (rule->set == rulenum)
2388 rule->set = new_set;
2389 else if (rule->set == new_set)
2390 rule->set = rulenum;
2391 }
2392 crit_exit();
2393 break;
2394 }
2395 return 0;
2396 }
2397
2398 /*
2399 * Clear counters for a specific rule.
2400 */
2401 static void
2402 clear_counters(struct ip_fw *rule, int log_only)
2403 {
2404 ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule);
2405
2406 if (log_only == 0) {
2407 rule->bcnt = rule->pcnt = 0;
2408 rule->timestamp = 0;
2409 }
2410 if (l->o.opcode == O_LOG)
2411 l->log_left = l->max_log;
2412 }
2413
2414 /**
2415 * Reset some or all counters on firewall rules.
2416 * @arg frwl is null to clear all entries, or contains a specific
2417 * rule number.
2418 * @arg log_only is 1 if we only want to reset logs, zero otherwise.
2419 */
2420 static int
2421 zero_entry(int rulenum, int log_only)
2422 {
2423 struct ip_fw *rule;
2424 char *msg;
2425
2426 if (rulenum == 0) {
2427 crit_enter();
2428 norule_counter = 0;
2429 for (rule = layer3_chain; rule; rule = rule->next)
2430 clear_counters(rule, log_only);
2431 crit_exit();
2432 msg = log_only ? "ipfw: All logging counts reset.\n"
2433 : "ipfw: Accounting cleared.\n";
2434 } else {
2435 int cleared = 0;
2436
2437 /*
2438 * We can have multiple rules with the same number, so we
2439 * need to clear them all.
2440 */
2441 for (rule = layer3_chain; rule; rule = rule->next) {
2442 if (rule->rulenum == rulenum) {
2443 crit_enter();
2444 while (rule && rule->rulenum == rulenum) {
2445 clear_counters(rule, log_only);
2446 rule = rule->next;
2447 }
2448 crit_exit();
2449 cleared = 1;
2450 break;
2451 }
2452 }
2453 if (!cleared) /* we did not find any matching rules */
2454 return (EINVAL);
2455 msg = log_only ? "ipfw: Entry %d logging count reset.\n"
2456 : "ipfw: Entry %d cleared.\n";
2457 }
2458 if (fw_verbose)
2459 log(LOG_SECURITY | LOG_NOTICE, msg, rulenum);
2460 return (0);
2461 }
2462
2463 /*
2464 * Check validity of the structure before insert.
2465 * Fortunately rules are simple, so this mostly need to check rule sizes.
2466 */
2467 static int
2468 ipfw_ctl_check_rule(struct ipfw_ioc_rule *rule, int size)
2469 {
2470 int l, cmdlen = 0;
2471 int have_action = 0;
2472 ipfw_insn *cmd;
2473
2474 /* Check for valid size */
2475 if (size < sizeof(*rule)) {
2476 kprintf("ipfw: rule too short\n");
2477 return EINVAL;
2478 }
2479 l = IOC_RULESIZE(rule);
2480 if (l != size) {
2481 kprintf("ipfw: size mismatch (have %d want %d)\n", size, l);
2482 return EINVAL;
2483 }
2484
2485 /*
2486 * Now go for the individual checks. Very simple ones, basically only
2487 * instruction sizes.
2488 */
2489 for (l = rule->cmd_len, cmd = rule->cmd; l > 0;
2490 l -= cmdlen, cmd += cmdlen) {
2491 cmdlen = F_LEN(cmd);
2492 if (cmdlen > l) {
2493 kprintf("ipfw: opcode %d size truncated\n",
2494 cmd->opcode);
2495 return EINVAL;
2496 }
2497 DEB(kprintf("ipfw: opcode %d\n", cmd->opcode);)
2498 switch (cmd->opcode) {
2499 case O_NOP:
2500 case O_PROBE_STATE:
2501 case O_KEEP_STATE:
2502 case O_PROTO:
2503 case O_IP_SRC_ME:
2504 case O_IP_DST_ME:
2505 case O_LAYER2:
2506 case O_IN:
2507 case O_FRAG:
2508 case O_IPOPT:
2509 case O_IPLEN:
2510 case O_IPID:
2511 case O_IPTOS:
2512 case O_IPPRECEDENCE:
2513 case O_IPTTL:
2514 case O_IPVER:
2515 case O_TCPWIN:
2516 case O_TCPFLAGS:
2517 case O_TCPOPTS:
2518 case O_ESTAB:
2519 if (cmdlen != F_INSN_SIZE(ipfw_insn))
2520 goto bad_size;
2521 break;
2522
2523 case O_UID:
2524 case O_GID:
2525 case O_IP_SRC:
2526 case O_IP_DST:
2527 case O_TCPSEQ:
2528 case O_TCPACK:
2529 case O_PROB:
2530 case O_ICMPTYPE:
2531 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32))
2532 goto bad_size;
2533 break;
2534
2535 case O_LIMIT:
2536 if (cmdlen != F_INSN_SIZE(ipfw_insn_limit))
2537 goto bad_size;
2538 break;
2539
2540 case O_LOG:
2541 if (cmdlen != F_INSN_SIZE(ipfw_insn_log))
2542 goto bad_size;
2543
2544 ((ipfw_insn_log *)cmd)->log_left =
2545 ((ipfw_insn_log *)cmd)->max_log;
2546
2547 break;
2548
2549 case O_IP_SRC_MASK:
2550 case O_IP_DST_MASK:
2551 if (cmdlen != F_INSN_SIZE(ipfw_insn_ip))
2552 goto bad_size;
2553 if (((ipfw_insn_ip *)cmd)->mask.s_addr == 0) {
2554 kprintf("ipfw: opcode %d, useless rule\n",
2555 cmd->opcode);
2556 return EINVAL;
2557 }
2558 break;
2559
2560 case O_IP_SRC_SET:
2561 case O_IP_DST_SET:
2562 if (cmd->arg1 == 0 || cmd->arg1 > 256) {
2563 kprintf("ipfw: invalid set size %d\n",
2564 cmd->arg1);
2565 return EINVAL;
2566 }
2567 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) +
2568 (cmd->arg1+31)/32 )
2569 goto bad_size;
2570 break;
2571
2572 case O_MACADDR2:
2573 if (cmdlen != F_INSN_SIZE(ipfw_insn_mac))
2574 goto bad_size;
2575 break;
2576
2577 case O_MAC_TYPE:
2578 case O_IP_SRCPORT:
2579 case O_IP_DSTPORT: /* XXX artificial limit, 30 port pairs */
2580 if (cmdlen < 2 || cmdlen > 31)
2581 goto bad_size;
2582 break;
2583
2584 case O_RECV:
2585 case O_XMIT:
2586 case O_VIA:
2587 if (cmdlen != F_INSN_SIZE(ipfw_insn_if))
2588 goto bad_size;
2589 break;
2590
2591 case O_PIPE:
2592 case O_QUEUE:
2593 if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe))
2594 goto bad_size;
2595 goto check_action;
2596
2597 case O_FORWARD_IP:
2598 if (cmdlen != F_INSN_SIZE(ipfw_insn_sa))
2599 goto bad_size;
2600 goto check_action;
2601
2602 case O_FORWARD_MAC: /* XXX not implemented yet */
2603 case O_CHECK_STATE:
2604 case O_COUNT:
2605 case O_ACCEPT:
2606 case O_DENY:
2607 case O_REJECT:
2608 case O_SKIPTO:
2609 case O_DIVERT:
2610 case O_TEE:
2611 if (cmdlen != F_INSN_SIZE(ipfw_insn))
2612 goto bad_size;
2613 check_action:
2614 if (have_action) {
2615 kprintf("ipfw: opcode %d, multiple actions"
2616 " not allowed\n",
2617 cmd->opcode);
2618 return EINVAL;
2619 }
2620 have_action = 1;
2621 if (l != cmdlen) {
2622 kprintf("ipfw: opcode %d, action must be"
2623 " last opcode\n",
2624 cmd->opcode);
2625 return EINVAL;
2626 }
2627 break;
2628 default:
2629 kprintf("ipfw: opcode %d, unknown opcode\n",
2630 cmd->opcode);
2631 return EINVAL;
2632 }
2633 }
2634 if (have_action == 0) {
2635 kprintf("ipfw: missing action\n");
2636 return EINVAL;
2637 }
2638 return 0;
2639
2640 bad_size:
2641 kprintf("ipfw: opcode %d size %d wrong\n",
2642 cmd->opcode, cmdlen);
2643 return EINVAL;
2644 }
2645
2646 static int
2647 ipfw_ctl_add_rule(struct sockopt *sopt)
2648 {
2649 struct ipfw_ioc_rule *ioc_rule;
2650 size_t size;
2651 int error;
2652
2653 size = sopt->sopt_valsize;
2654 if (size > (sizeof(uint32_t) * IPFW_RULE_SIZE_MAX) ||
2655 size < sizeof(*ioc_rule)) {
2656 return EINVAL;
2657 }
2658 if (size != (sizeof(uint32_t) * IPFW_RULE_SIZE_MAX)) {
2659 sopt->sopt_val = krealloc(sopt->sopt_val, sizeof(uint32_t) *
2660 IPFW_RULE_SIZE_MAX, M_TEMP, M_WAITOK);
2661 }
2662 ioc_rule = sopt->sopt_val;
2663
2664 error = ipfw_ctl_check_rule(ioc_rule, size);
2665 if (error)
2666 return error;
2667
2668 error = ipfw_add_rule(&layer3_chain, ioc_rule);
2669 if (error)
2670 return error;
2671
2672 if (sopt->sopt_dir == SOPT_GET)
2673 sopt->sopt_valsize = IOC_RULESIZE(ioc_rule);
2674 return 0;
2675 }
2676
2677 static void *
2678 ipfw_copy_rule(const struct ip_fw *rule, struct ipfw_ioc_rule *ioc_rule)
2679 {
2680 ioc_rule->act_ofs = rule->act_ofs;
2681 ioc_rule->cmd_len = rule->cmd_len;
2682 ioc_rule->rulenum = rule->rulenum;
2683 ioc_rule->set = rule->set;
2684 ioc_rule->usr_flags = rule->usr_flags;
2685
2686 ioc_rule->set_disable = set_disable;
2687 ioc_rule->static_count = static_count;
2688 ioc_rule->static_len = static_ioc_len;
2689
2690 ioc_rule->pcnt = rule->pcnt;
2691 ioc_rule->bcnt = rule->bcnt;
2692 ioc_rule->timestamp = rule->timestamp;
2693
2694 bcopy(rule->cmd, ioc_rule->cmd, ioc_rule->cmd_len * 4 /* XXX */);
2695
2696 return ((uint8_t *)ioc_rule + IOC_RULESIZE(ioc_rule));
2697 }
2698
2699 static void
2700 ipfw_copy_state(const ipfw_dyn_rule *dyn_rule,
2701 struct ipfw_ioc_state *ioc_state)
2702 {
2703 const struct ipfw_flow_id *id;
2704 struct ipfw_ioc_flowid *ioc_id;
2705
2706 ioc_state->expire = TIME_LEQ(dyn_rule->expire, time_second) ?
2707 0 : dyn_rule->expire - time_second;
2708 ioc_state->pcnt = dyn_rule->pcnt;
2709 ioc_state->bcnt = dyn_rule->bcnt;
2710
2711 ioc_state->dyn_type = dyn_rule->dyn_type;
2712 ioc_state->count = dyn_rule->count;
2713
2714 ioc_state->rulenum = dyn_rule->rule->rulenum;
2715
2716 id = &dyn_rule->id;
2717 ioc_id = &ioc_state->id;
2718
2719 ioc_id->type = ETHERTYPE_IP;
2720 ioc_id->u.ip.dst_ip = id->dst_ip;
2721 ioc_id->u.ip.src_ip = id->src_ip;
2722 ioc_id->u.ip.dst_port = id->dst_port;
2723 ioc_id->u.ip.src_port = id->src_port;
2724 ioc_id->u.ip.proto = id->proto;
2725 }
2726
2727 static int
2728 ipfw_ctl_get_rules(struct sockopt *sopt)
2729 {
2730 struct ip_fw *rule;
2731 void *bp;
2732 size_t size;
2733
2734 /*
2735 * pass up a copy of the current rules. Static rules
2736 * come first (the last of which has number IPFW_DEFAULT_RULE),
2737 * followed by a possibly empty list of dynamic rule.
2738 */
2739 crit_enter();
2740
2741 size = static_ioc_len; /* size of static rules */
2742 if (ipfw_dyn_v) /* add size of dyn.rules */
2743 size += (dyn_count * sizeof(struct ipfw_ioc_state));
2744
2745 if (sopt->sopt_valsize < size) {
2746 /* short length, no need to return incomplete rules */
2747 /* XXX: if superuser, no need to zero buffer */
2748 bzero(sopt->sopt_val, sopt->sopt_valsize);
2749 return 0;
2750 }
2751 bp = sopt->sopt_val;
2752
2753 for (rule = layer3_chain; rule; rule = rule->next)
2754 bp = ipfw_copy_rule(rule, bp);
2755
2756 if (ipfw_dyn_v) {
2757 struct ipfw_ioc_state *ioc_state;
2758 int i;
2759
2760 ioc_state = bp;
2761 for (i = 0; i < curr_dyn_buckets; i++) {
2762 ipfw_dyn_rule *p;
2763
2764 for (p = ipfw_dyn_v[i]; p != NULL;
2765 p = p->next, ioc_state++)
2766 ipfw_copy_state(p, ioc_state);
2767 }
2768 }
2769
2770 crit_exit();
2771
2772 sopt->sopt_valsize = size;
2773 return 0;
2774 }
2775
2776 /**
2777 * {set|get}sockopt parser.
2778 */
2779 static int
2780 ipfw_ctl(struct sockopt *sopt)
2781 {
2782 int error, rulenum;
2783 uint32_t *masks;
2784 size_t size;
2785
2786 error = 0;
2787
2788 switch (sopt->sopt_name) {
2789 case IP_FW_GET:
2790 error = ipfw_ctl_get_rules(sopt);
2791 break;
2792
2793 case IP_FW_FLUSH:
2794 /*
2795 * Normally we cannot release the lock on each iteration.
2796 * We could do it here only because we start from the head all
2797 * the times so there is no risk of missing some entries.
2798 * On the other hand, the risk is that we end up with
2799 * a very inconsistent ruleset, so better keep the lock
2800 * around the whole cycle.
2801 *
2802 * XXX this code can be improved by resetting the head of
2803 * the list to point to the default rule, and then freeing
2804 * the old list without the need for a lock.
2805 */
2806
2807 crit_enter();
2808 free_chain(&layer3_chain, 0 /* keep default rule */);
2809 crit_exit();
2810 break;
2811
2812 case IP_FW_ADD:
2813 error = ipfw_ctl_add_rule(sopt);
2814 break;
2815
2816 case IP_FW_DEL:
2817 /*
2818 * IP_FW_DEL is used for deleting single rules or sets,
2819 * and (ab)used to atomically manipulate sets. Argument size
2820 * is used to distinguish between the two:
2821 * sizeof(uint32_t)
2822 * delete single rule or set of rules,
2823 * or reassign rules (or sets) to a different set.
2824 * 2*sizeof(uint32_t)
2825 * atomic disable/enable sets.
2826 * first uint32_t contains sets to be disabled,
2827 * second uint32_t contains sets to be enabled.
2828 */
2829 masks = sopt->sopt_val;
2830 size = sopt->sopt_valsize;
2831 if (size == sizeof(*masks)) {
2832 /*
2833 * Delete or reassign static rule
2834 */
2835 error = del_entry(&layer3_chain, masks[0]);
2836 } else if (size == (2 * sizeof(*masks))) {
2837 /*
2838 * Set enable/disable
2839 */
2840 crit_enter();
2841
2842 set_disable =
2843 (set_disable | masks[0]) & ~masks[1] &
2844 ~(1 << 31); /* set 31 always enabled */
2845
2846 crit_exit();
2847 } else {
2848 error = EINVAL;
2849 }
2850 break;
2851
2852 case IP_FW_ZERO:
2853 case IP_FW_RESETLOG: /* argument is an int, the rule number */
2854 rulenum=0;
2855
2856 if (sopt->sopt_val != 0) {
2857 error = soopt_to_kbuf(sopt, &rulenum,
2858 sizeof(int), sizeof(int));
2859 if (error)
2860 break;
2861 }
2862 error = zero_entry(rulenum, sopt->sopt_name == IP_FW_RESETLOG);
2863 break;
2864
2865 default:
2866 kprintf("ipfw_ctl invalid option %d\n", sopt->sopt_name);
2867 error = EINVAL;
2868 }
2869 return error;
2870 }
2871
2872 /*
2873 * This procedure is only used to handle keepalives. It is invoked
2874 * every dyn_keepalive_period
2875 */
2876 static void
2877 ipfw_tick(void *unused __unused)
2878 {
2879 int i;
2880 ipfw_dyn_rule *q;
2881
2882 if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0)
2883 goto done;
2884
2885 crit_enter();
2886 for (i = 0; i < curr_dyn_buckets; i++) {
2887 for (q = ipfw_dyn_v[i]; q; q = q->next) {
2888 if (q->dyn_type == O_LIMIT_PARENT)
2889 continue;
2890 if (q->id.proto != IPPROTO_TCP)
2891 continue;
2892 if ((q->state & BOTH_SYN) != BOTH_SYN)
2893 continue;
2894 if (TIME_LEQ(time_second + dyn_keepalive_interval,
2895 q->expire))
2896 continue; /* too early */
2897 if (TIME_LEQ(q->expire, time_second))
2898 continue; /* too late, rule expired */
2899
2900 send_pkt(&q->id, q->ack_rev - 1, q->ack_fwd, TH_SYN);
2901 send_pkt(&q->id, q->ack_fwd - 1, q->ack_rev, 0);
2902 }
2903 }
2904 crit_exit();
2905 done:
2906 callout_reset(&ipfw_timeout_h, dyn_keepalive_period * hz,
2907 ipfw_tick, NULL);
2908 }
2909
2910 static void
2911 ipfw_init_default_rule(struct ip_fw **head)
2912 {
2913 struct ip_fw *def_rule;
2914
2915 KKASSERT(*head == NULL);
2916
2917 def_rule = kmalloc(sizeof(*def_rule), M_IPFW, M_WAITOK | M_ZERO);
2918
2919 def_rule->act_ofs = 0;
2920 def_rule->rulenum = IPFW_DEFAULT_RULE;
2921 def_rule->cmd_len = 1;
2922 def_rule->set = 31;
2923
2924 def_rule->cmd[0].len = 1;
2925 #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
2926 def_rule->cmd[0].opcode = O_ACCEPT;
2927 #else
2928 def_rule->cmd[0].opcode = O_DENY;
2929 #endif
2930
2931 def_rule->refcnt = 1;
2932
2933 *head = def_rule;
2934 ipfw_inc_static_count(def_rule);
2935
2936 /* Install the default rule */
2937 ip_fw_default_rule = def_rule;
2938 }
2939
2940 static void
2941 ipfw_init_dispatch(struct netmsg *nmsg)
2942 {
2943 int error = 0;
2944
2945 crit_enter();
2946
2947 if (IPFW_LOADED) {
2948 kprintf("IP firewall already loaded\n");
2949 error = EEXIST;
2950 goto reply;
2951 }
2952
2953 ip_fw_chk_ptr = ipfw_chk;
2954 ip_fw_ctl_ptr = ipfw_ctl;
2955 ip_fw_dn_io_ptr = ipfw_dummynet_io;
2956
2957 layer3_chain = NULL;
2958 ipfw_init_default_rule(&layer3_chain);
2959
2960 kprintf("ipfw2 initialized, divert %s, "
2961 "rule-based forwarding enabled, default to %s, logging ",
2962 #ifdef IPDIVERT
2963 "enabled",
2964 #else
2965 "disabled",
2966 #endif
2967 ip_fw_default_rule->cmd[0].opcode == O_ACCEPT ?
2968 "accept" : "deny");
2969
2970 #ifdef IPFIREWALL_VERBOSE
2971 fw_verbose = 1;
2972 #endif
2973 #ifdef IPFIREWALL_VERBOSE_LIMIT
2974 verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
2975 #endif
2976 if (fw_verbose == 0) {
2977 kprintf("disabled\n");
2978 } else if (verbose_limit == 0) {
2979 kprintf("unlimited\n");
2980 } else {
2981 kprintf("limited to %d packets/entry by default\n",
2982 verbose_limit);
2983 }
2984 callout_init(&ipfw_timeout_h);
2985
2986 ip_fw_loaded = 1;
2987 callout_reset(&ipfw_timeout_h, hz, ipfw_tick, NULL);
2988 reply:
2989 crit_exit();
2990 lwkt_replymsg(&nmsg->nm_lmsg, error);
2991 }
2992
2993 static int
2994 ipfw_init(void)
2995 {
2996 struct netmsg smsg;
2997
2998 netmsg_init(&smsg, &curthread->td_msgport, 0, ipfw_init_dispatch);
2999 return lwkt_domsg(cpu_portfn(0), &smsg.nm_lmsg, 0);
3000 }
3001
3002 #ifdef KLD_MODULE
3003
3004 static void
3005 ipfw_fini_dispatch(struct netmsg *nmsg)
3006 {
3007 int error = 0;
3008
3009 crit_enter();
3010
3011 if (ipfw_refcnt != 0) {
3012 error = EBUSY;
3013 goto reply;
3014 }
3015
3016 callout_stop(&ipfw_timeout_h);
3017
3018 ip_fw_loaded = 0;
3019 netmsg_service_sync();
3020
3021 ip_fw_chk_ptr = NULL;
3022 ip_fw_ctl_ptr = NULL;
3023 ip_fw_dn_io_ptr = NULL;
3024 free_chain(&layer3_chain, 1 /* kill default rule */);
3025
3026 kprintf("IP firewall unloaded\n");
3027 reply:
3028 crit_exit();
3029 lwkt_replymsg(&nmsg->nm_lmsg, error);
3030 }
3031
3032 static int
3033 ipfw_fini(void)
3034 {
3035 struct netmsg smsg;
3036
3037 netmsg_init(&smsg, &curthread->td_msgport, 0, ipfw_fini_dispatch);
3038 return lwkt_domsg(cpu_portfn(0), &smsg.nm_lmsg, 0);
3039 }
3040
3041 #endif /* KLD_MODULE */
3042
3043 static int
3044 ipfw_modevent(module_t mod, int type, void *unused)
3045 {
3046 int err = 0;
3047
3048 switch (type) {
3049 case MOD_LOAD:
3050 err = ipfw_init();
3051 break;
3052
3053 case MOD_UNLOAD:
3054 #ifndef KLD_MODULE
3055 kprintf("ipfw statically compiled, cannot unload\n");
3056 err = EBUSY;
3057 #else
3058 err = ipfw_fini();
3059 #endif
3060 break;
3061 default:
3062 break;
3063 }
3064 return err;
3065 }
3066
3067 static moduledata_t ipfwmod = {
3068 "ipfw",
3069 ipfw_modevent,
3070 0
3071 };
3072 DECLARE_MODULE(ipfw, ipfwmod, SI_SUB_PROTO_END, SI_ORDER_ANY);
3073 MODULE_VERSION(ipfw, 1);
MP support for (parts of) the network stack