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[dragonfly.git] / sys / net / ipfw / ip_fw.c
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1/*
2 * Copyright (c) 1993 Daniel Boulet
3 * Copyright (c) 1994 Ugen J.S.Antsilevich
4 * Copyright (c) 1996 Alex Nash
5 * Copyright (c) 2000-2001 Luigi Rizzo
6 *
7 * Redistribution and use in source forms, with and without modification,
8 * are permitted provided that this entire comment appears intact.
9 *
10 * Redistribution in binary form may occur without any restrictions.
11 * Obviously, it would be nice if you gave credit where credit is due
12 * but requiring it would be too onerous.
13 *
14 * This software is provided ``AS IS'' without any warranties of any kind.
15 *
16 * $FreeBSD: src/sys/netinet/ip_fw.c,v 1.131.2.39 2003/01/20 02:23:07 iedowse Exp $
2256ba69 17 * $DragonFly: src/sys/net/ipfw/Attic/ip_fw.c,v 1.3 2003/07/26 21:00:04 rob Exp $
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18 */
19
20#define DEB(x)
21#define DDB(x) x
22
23/*
24 * Implement IP packet firewall
25 */
26
27#if !defined(KLD_MODULE)
28#include "opt_ipfw.h"
29#include "opt_ipdn.h"
30#include "opt_ipdivert.h"
31#include "opt_inet.h"
32#ifndef INET
33#error IPFIREWALL requires INET.
34#endif /* INET */
35#endif
36
37#if !(IPFW2)
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/malloc.h>
42#include <sys/mbuf.h>
43#include <sys/kernel.h>
44#include <sys/proc.h>
45#include <sys/socket.h>
46#include <sys/socketvar.h>
47#include <sys/sysctl.h>
48#include <sys/syslog.h>
49#include <sys/ucred.h>
50#include <net/if.h>
51#include <net/route.h>
52#include <netinet/in.h>
53#include <netinet/in_systm.h>
54#include <netinet/in_var.h>
55#include <netinet/in_pcb.h>
56#include <netinet/ip.h>
57#include <netinet/ip_var.h>
58#include <netinet/ip_icmp.h>
59#include <netinet/ip_fw.h>
60#include <netinet/ip_dummynet.h>
61#include <netinet/tcp.h>
62#include <netinet/tcp_timer.h>
63#include <netinet/tcp_var.h>
64#include <netinet/tcpip.h>
65#include <netinet/udp.h>
66#include <netinet/udp_var.h>
67
68#include <netinet/if_ether.h> /* XXX ethertype_ip */
69
70static int fw_debug = 1;
71#ifdef IPFIREWALL_VERBOSE
72static int fw_verbose = 1;
73#else
74static int fw_verbose = 0;
75#endif
76#ifdef IPFIREWALL_VERBOSE_LIMIT
77static int fw_verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
78#else
79static int fw_verbose_limit = 0;
80#endif
81
82/*
83 * Right now, two fields in the IP header are changed to host format
84 * by the IP layer before calling the firewall. Ideally, we would like
85 * to have them in network format so that the packet can be
86 * used as it comes from the device driver (and is thus readonly).
87 */
88
89static u_int64_t counter; /* counter for ipfw_report(NULL...) */
90
91#define IPFW_DEFAULT_RULE ((u_int)(u_short)~0)
92
93LIST_HEAD (ip_fw_head, ip_fw) ip_fw_chain_head;
94
95MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
96
97#ifdef SYSCTL_NODE
98SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
99SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,
100 &fw_enable, 0, "Enable ipfw");
101SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW,
102 &fw_one_pass, 0,
103 "Only do a single pass through ipfw when using dummynet(4)");
104SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW,
105 &fw_debug, 0, "Enable printing of debug ip_fw statements");
106SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW,
107 &fw_verbose, 0, "Log matches to ipfw rules");
108SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW,
109 &fw_verbose_limit, 0, "Set upper limit of matches of ipfw rules logged");
110
111/*
112 * Extension for stateful ipfw.
113 *
114 * Dynamic rules are stored in lists accessed through a hash table
115 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
116 * be modified through the sysctl variable dyn_buckets which is
117 * updated when the table becomes empty.
118 *
119 * XXX currently there is only one list, ipfw_dyn.
120 *
121 * When a packet is received, it is first hashed, then matched
122 * against the entries in the corresponding list.
123 * Matching occurs according to the rule type. The default is to
124 * match the four fields and the protocol, and rules are bidirectional.
125 *
126 * For a busy proxy/web server we will have lots of connections to
127 * the server. We could decide for a rule type where we ignore
128 * ports (different hashing) and avoid special SYN/RST/FIN handling.
129 *
130 * XXX when we decide to support more than one rule type, we should
131 * repeat the hashing multiple times uing only the useful fields.
132 * Or, we could run the various tests in parallel, because the
133 * 'move to front' technique should shorten the average search.
134 *
135 * The lifetime of dynamic rules is regulated by dyn_*_lifetime,
136 * measured in seconds and depending on the flags.
137 *
138 * The total number of dynamic rules is stored in dyn_count.
139 * The max number of dynamic rules is dyn_max. When we reach
140 * the maximum number of rules we do not create anymore. This is
141 * done to avoid consuming too much memory, but also too much
142 * time when searching on each packet (ideally, we should try instead
143 * to put a limit on the length of the list on each bucket...).
144 *
145 * Each dynamic rules holds a pointer to the parent ipfw rule so
146 * we know what action to perform. Dynamic rules are removed when
147 * the parent rule is deleted.
148 * There are some limitations with dynamic rules -- we do not
149 * obey the 'randomized match', and we do not do multiple
150 * passes through the firewall.
151 * XXX check the latter!!!
152 */
153static struct ipfw_dyn_rule **ipfw_dyn_v = NULL ;
154static u_int32_t dyn_buckets = 256 ; /* must be power of 2 */
155static u_int32_t curr_dyn_buckets = 256 ; /* must be power of 2 */
156
157/*
158 * timeouts for various events in handing dynamic rules.
159 */
160static u_int32_t dyn_ack_lifetime = 300 ;
161static u_int32_t dyn_syn_lifetime = 20 ;
162static u_int32_t dyn_fin_lifetime = 1 ;
163static u_int32_t dyn_rst_lifetime = 1 ;
164static u_int32_t dyn_udp_lifetime = 10 ;
165static u_int32_t dyn_short_lifetime = 5 ;
166
167/*
168 * after reaching 0, dynamic rules are considered still valid for
169 * an additional grace time, unless there is lack of resources.
170 */
171static u_int32_t dyn_grace_time = 10 ;
172
173static u_int32_t static_count = 0 ; /* # of static rules */
174static u_int32_t dyn_count = 0 ; /* # of dynamic rules */
175static u_int32_t dyn_max = 1000 ; /* max # of dynamic rules */
176
177SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW,
178 &dyn_buckets, 0, "Number of dyn. buckets");
179SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD,
180 &curr_dyn_buckets, 0, "Current Number of dyn. buckets");
181SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD,
182 &dyn_count, 0, "Number of dyn. rules");
183SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW,
184 &dyn_max, 0, "Max number of dyn. rules");
185SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD,
186 &static_count, 0, "Number of static rules");
187SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW,
188 &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks");
189SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW,
190 &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn");
191SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW,
192 &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin");
193SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW,
194 &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst");
195SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW,
196 &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP");
197SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW,
198 &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations");
199SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_grace_time, CTLFLAG_RD,
200 &dyn_grace_time, 0, "Grace time for dyn. rules");
201
202#endif /* SYSCTL_NODE */
203
204#define dprintf(a) do { \
205 if (fw_debug) \
206 printf a; \
207 } while (0)
208#define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
209
210static int add_entry (struct ip_fw_head *chainptr, struct ip_fw *frwl);
211static int del_entry (struct ip_fw_head *chainptr, u_short number);
212static int zero_entry (struct ip_fw *, int);
213static int check_ipfw_struct (struct ip_fw *m);
214static int iface_match (struct ifnet *ifp, union ip_fw_if *ifu,
215 int byname);
216static int ipopts_match (struct ip *ip, struct ip_fw *f);
217static __inline int
218 port_match (u_short *portptr, int nports, u_short port,
219 int range_flag, int mask);
220static int tcpflg_match (struct tcphdr *tcp, struct ip_fw *f);
221static int icmptype_match (struct icmp * icmp, struct ip_fw * f);
222static void ipfw_report (struct ip_fw *f, struct ip *ip, int ip_off,
223 int ip_len, struct ifnet *rif,
224 struct ifnet *oif);
225
226static void flush_rule_ptrs(void);
227
228static ip_fw_chk_t ip_fw_chk;
229static int ip_fw_ctl (struct sockopt *sopt);
230
231ip_dn_ruledel_t *ip_dn_ruledel_ptr = NULL;
232
233static char err_prefix[] = "ip_fw_ctl:";
234
235/*
236 * Returns 1 if the port is matched by the vector, 0 otherwise
237 */
238static __inline int
239port_match(u_short *portptr, int nports, u_short port, int range_flag, int mask)
240{
241 if (!nports)
242 return 1;
243 if (mask) {
244 if ( 0 == ((portptr[0] ^ port) & portptr[1]) )
245 return 1;
246 nports -= 2;
247 portptr += 2;
248 }
249 if (range_flag) {
250 if (portptr[0] <= port && port <= portptr[1])
251 return 1;
252 nports -= 2;
253 portptr += 2;
254 }
255 while (nports-- > 0)
256 if (*portptr++ == port)
257 return 1;
258 return 0;
259}
260
261static int
262tcpflg_match(struct tcphdr *tcp, struct ip_fw *f)
263{
264 u_char flg_set, flg_clr;
265
266 /*
267 * If an established connection is required, reject packets that
268 * have only SYN of RST|ACK|SYN set. Otherwise, fall through to
269 * other flag requirements.
270 */
271 if ((f->fw_ipflg & IP_FW_IF_TCPEST) &&
272 ((tcp->th_flags & (IP_FW_TCPF_RST | IP_FW_TCPF_ACK |
273 IP_FW_TCPF_SYN)) == IP_FW_TCPF_SYN))
274 return 0;
275
276 flg_set = tcp->th_flags & f->fw_tcpf;
277 flg_clr = tcp->th_flags & f->fw_tcpnf;
278
279 if (flg_set != f->fw_tcpf)
280 return 0;
281 if (flg_clr)
282 return 0;
283
284 return 1;
285}
286
287static int
288icmptype_match(struct icmp *icmp, struct ip_fw *f)
289{
290 int type;
291
292 if (!(f->fw_flg & IP_FW_F_ICMPBIT))
293 return(1);
294
295 type = icmp->icmp_type;
296
297 /* check for matching type in the bitmap */
298 if (type < IP_FW_ICMPTYPES_MAX &&
299 (f->fw_uar.fw_icmptypes[type / (sizeof(unsigned) * NBBY)] &
300 (1U << (type % (sizeof(unsigned) * NBBY)))))
301 return(1);
302
303 return(0); /* no match */
304}
305
306static int
307is_icmp_query(struct ip *ip)
308{
309 const struct icmp *icmp;
310 int icmp_type;
311
312 icmp = (struct icmp *)((u_int32_t *)ip + ip->ip_hl);
313 icmp_type = icmp->icmp_type;
314
315 if (icmp_type == ICMP_ECHO || icmp_type == ICMP_ROUTERSOLICIT ||
316 icmp_type == ICMP_TSTAMP || icmp_type == ICMP_IREQ ||
317 icmp_type == ICMP_MASKREQ)
318 return(1);
319
320 return(0);
321}
322
323static int
324ipopts_match(struct ip *ip, struct ip_fw *f)
325{
2256ba69 326 u_char *cp;
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327 int opt, optlen, cnt;
328 u_char opts, nopts, nopts_sve;
329
330 cp = (u_char *)(ip + 1);
331 cnt = (ip->ip_hl << 2) - sizeof (struct ip);
332 opts = f->fw_ipopt;
333 nopts = nopts_sve = f->fw_ipnopt;
334
335 for (; cnt > 0; cnt -= optlen, cp += optlen) {
336 opt = cp[IPOPT_OPTVAL];
337 if (opt == IPOPT_EOL)
338 break;
339 if (opt == IPOPT_NOP)
340 optlen = 1;
341 else {
342 optlen = cp[IPOPT_OLEN];
343 if (optlen <= 0 || optlen > cnt) {
344 return 0; /*XXX*/
345 }
346 }
347 switch (opt) {
348
349 default:
350 break;
351
352 case IPOPT_LSRR:
353 opts &= ~IP_FW_IPOPT_LSRR;
354 nopts &= ~IP_FW_IPOPT_LSRR;
355 break;
356
357 case IPOPT_SSRR:
358 opts &= ~IP_FW_IPOPT_SSRR;
359 nopts &= ~IP_FW_IPOPT_SSRR;
360 break;
361
362 case IPOPT_RR:
363 opts &= ~IP_FW_IPOPT_RR;
364 nopts &= ~IP_FW_IPOPT_RR;
365 break;
366 case IPOPT_TS:
367 opts &= ~IP_FW_IPOPT_TS;
368 nopts &= ~IP_FW_IPOPT_TS;
369 break;
370 }
371 if (opts == nopts)
372 break;
373 }
374 if (opts == 0 && nopts == nopts_sve)
375 return 1;
376 else
377 return 0;
378}
379
380static int
381tcpopts_match(struct tcphdr *tcp, struct ip_fw *f)
382{
2256ba69 383 u_char *cp;
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384 int opt, optlen, cnt;
385 u_char opts, nopts, nopts_sve;
386
387 cp = (u_char *)(tcp + 1);
388 cnt = (tcp->th_off << 2) - sizeof (struct tcphdr);
389 opts = f->fw_tcpopt;
390 nopts = nopts_sve = f->fw_tcpnopt;
391
392 for (; cnt > 0; cnt -= optlen, cp += optlen) {
393 opt = cp[0];
394 if (opt == TCPOPT_EOL)
395 break;
396 if (opt == TCPOPT_NOP)
397 optlen = 1;
398 else {
399 optlen = cp[1];
400 if (optlen <= 0)
401 break;
402 }
403
404
405 switch (opt) {
406
407 default:
408 break;
409
410 case TCPOPT_MAXSEG:
411 opts &= ~IP_FW_TCPOPT_MSS;
412 nopts &= ~IP_FW_TCPOPT_MSS;
413 break;
414
415 case TCPOPT_WINDOW:
416 opts &= ~IP_FW_TCPOPT_WINDOW;
417 nopts &= ~IP_FW_TCPOPT_WINDOW;
418 break;
419
420 case TCPOPT_SACK_PERMITTED:
421 case TCPOPT_SACK:
422 opts &= ~IP_FW_TCPOPT_SACK;
423 nopts &= ~IP_FW_TCPOPT_SACK;
424 break;
425
426 case TCPOPT_TIMESTAMP:
427 opts &= ~IP_FW_TCPOPT_TS;
428 nopts &= ~IP_FW_TCPOPT_TS;
429 break;
430
431 case TCPOPT_CC:
432 case TCPOPT_CCNEW:
433 case TCPOPT_CCECHO:
434 opts &= ~IP_FW_TCPOPT_CC;
435 nopts &= ~IP_FW_TCPOPT_CC;
436 break;
437 }
438 if (opts == nopts)
439 break;
440 }
441 if (opts == 0 && nopts == nopts_sve)
442 return 1;
443 else
444 return 0;
445}
446
447static int
448iface_match(struct ifnet *ifp, union ip_fw_if *ifu, int byname)
449{
450 /* Check by name or by IP address */
451 if (byname) {
452 /* Check unit number (-1 is wildcard) */
453 if (ifu->fu_via_if.unit != -1
454 && ifp->if_unit != ifu->fu_via_if.unit)
455 return(0);
456 /* Check name */
457 if (strncmp(ifp->if_name, ifu->fu_via_if.name, FW_IFNLEN))
458 return(0);
459 return(1);
460 } else if (ifu->fu_via_ip.s_addr != 0) { /* Zero == wildcard */
461 struct ifaddr *ia;
462
463 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
464 if (ia->ifa_addr == NULL)
465 continue;
466 if (ia->ifa_addr->sa_family != AF_INET)
467 continue;
468 if (ifu->fu_via_ip.s_addr != ((struct sockaddr_in *)
469 (ia->ifa_addr))->sin_addr.s_addr)
470 continue;
471 return(1);
472 }
473 return(0);
474 }
475 return(1);
476}
477
478static void
479ipfw_report(struct ip_fw *f, struct ip *ip, int ip_off, int ip_len,
480 struct ifnet *rif, struct ifnet *oif)
481{
482 struct tcphdr *const tcp = (struct tcphdr *) ((u_int32_t *) ip+ ip->ip_hl);
483 struct udphdr *const udp = (struct udphdr *) ((u_int32_t *) ip+ ip->ip_hl);
484 struct icmp *const icmp = (struct icmp *) ((u_int32_t *) ip + ip->ip_hl);
485 u_int64_t count;
486 char *action;
487 char action2[32], proto[47], name[18], fragment[27];
488 int len;
489 int offset = ip_off & IP_OFFMASK;
490
491 count = f ? f->fw_pcnt : ++counter;
492 if ((f == NULL && fw_verbose_limit != 0 && count > fw_verbose_limit) ||
493 (f && f->fw_logamount != 0 && count > f->fw_loghighest))
494 return;
495
496 /* Print command name */
497 snprintf(SNPARGS(name, 0), "ipfw: %d", f ? f->fw_number : -1);
498
499 action = action2;
500 if (!f)
501 action = "Refuse";
502 else {
503 switch (f->fw_flg & IP_FW_F_COMMAND) {
504 case IP_FW_F_DENY:
505 action = "Deny";
506 break;
507 case IP_FW_F_REJECT:
508 if (f->fw_reject_code == IP_FW_REJECT_RST)
509 action = "Reset";
510 else
511 action = "Unreach";
512 break;
513 case IP_FW_F_ACCEPT:
514 action = "Accept";
515 break;
516 case IP_FW_F_COUNT:
517 action = "Count";
518 break;
519#ifdef IPDIVERT
520 case IP_FW_F_DIVERT:
521 snprintf(SNPARGS(action2, 0), "Divert %d",
522 f->fw_divert_port);
523 break;
524 case IP_FW_F_TEE:
525 snprintf(SNPARGS(action2, 0), "Tee %d",
526 f->fw_divert_port);
527 break;
528#endif
529 case IP_FW_F_SKIPTO:
530 snprintf(SNPARGS(action2, 0), "SkipTo %d",
531 f->fw_skipto_rule);
532 break;
533 case IP_FW_F_PIPE:
534 snprintf(SNPARGS(action2, 0), "Pipe %d",
535 f->fw_skipto_rule);
536 break;
537 case IP_FW_F_QUEUE:
538 snprintf(SNPARGS(action2, 0), "Queue %d",
539 f->fw_skipto_rule);
540 break;
541
542 case IP_FW_F_FWD:
543 if (f->fw_fwd_ip.sin_port)
544 snprintf(SNPARGS(action2, 0),
545 "Forward to %s:%d",
546 inet_ntoa(f->fw_fwd_ip.sin_addr),
547 f->fw_fwd_ip.sin_port);
548 else
549 snprintf(SNPARGS(action2, 0), "Forward to %s",
550 inet_ntoa(f->fw_fwd_ip.sin_addr));
551 break;
552
553 default:
554 action = "UNKNOWN";
555 break;
556 }
557 }
558
559 switch (ip->ip_p) {
560 case IPPROTO_TCP:
561 len = snprintf(SNPARGS(proto, 0), "TCP %s",
562 inet_ntoa(ip->ip_src));
563 if (offset == 0)
564 len += snprintf(SNPARGS(proto, len), ":%d ",
565 ntohs(tcp->th_sport));
566 else
567 len += snprintf(SNPARGS(proto, len), " ");
568 len += snprintf(SNPARGS(proto, len), "%s",
569 inet_ntoa(ip->ip_dst));
570 if (offset == 0)
571 snprintf(SNPARGS(proto, len), ":%d",
572 ntohs(tcp->th_dport));
573 break;
574 case IPPROTO_UDP:
575 len = snprintf(SNPARGS(proto, 0), "UDP %s",
576 inet_ntoa(ip->ip_src));
577 if (offset == 0)
578 len += snprintf(SNPARGS(proto, len), ":%d ",
579 ntohs(udp->uh_sport));
580 else
581 len += snprintf(SNPARGS(proto, len), " ");
582 len += snprintf(SNPARGS(proto, len), "%s",
583 inet_ntoa(ip->ip_dst));
584 if (offset == 0)
585 snprintf(SNPARGS(proto, len), ":%d",
586 ntohs(udp->uh_dport));
587 break;
588 case IPPROTO_ICMP:
589 if (offset == 0)
590 len = snprintf(SNPARGS(proto, 0), "ICMP:%u.%u ",
591 icmp->icmp_type, icmp->icmp_code);
592 else
593 len = snprintf(SNPARGS(proto, 0), "ICMP ");
594 len += snprintf(SNPARGS(proto, len), "%s",
595 inet_ntoa(ip->ip_src));
596 snprintf(SNPARGS(proto, len), " %s", inet_ntoa(ip->ip_dst));
597 break;
598 default:
599 len = snprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p,
600 inet_ntoa(ip->ip_src));
601 snprintf(SNPARGS(proto, len), " %s", inet_ntoa(ip->ip_dst));
602 break;
603 }
604
605 if (ip_off & (IP_MF | IP_OFFMASK))
606 snprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)",
607 ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2),
608 offset << 3,
609 (ip_off & IP_MF) ? "+" : "");
610 else
611 fragment[0] = '\0';
612 if (oif)
613 log(LOG_SECURITY | LOG_INFO, "%s %s %s out via %s%d%s\n",
614 name, action, proto, oif->if_name, oif->if_unit, fragment);
615 else if (rif)
616 log(LOG_SECURITY | LOG_INFO, "%s %s %s in via %s%d%s\n", name,
617 action, proto, rif->if_name, rif->if_unit, fragment);
618 else
619 log(LOG_SECURITY | LOG_INFO, "%s %s %s%s\n", name, action,
620 proto, fragment);
621 if ((f ? f->fw_logamount != 0 : 1) &&
622 count == (f ? f->fw_loghighest : fw_verbose_limit))
623 log(LOG_SECURITY | LOG_NOTICE,
624 "ipfw: limit %d reached on entry %d\n",
625 f ? f->fw_logamount : fw_verbose_limit,
626 f ? f->fw_number : -1);
627}
628
629static __inline int
630hash_packet(struct ipfw_flow_id *id)
631{
632 u_int32_t i ;
633
634 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
635 i &= (curr_dyn_buckets - 1) ;
636 return i ;
637}
638
639/**
640 * unlink a dynamic rule from a chain. prev is a pointer to
641 * the previous one, q is a pointer to the rule to delete,
642 * head is a pointer to the head of the queue.
643 * Modifies q and potentially also head.
644 */
645#define UNLINK_DYN_RULE(prev, head, q) { \
646 struct ipfw_dyn_rule *old_q = q; \
647 \
648 /* remove a refcount to the parent */ \
649 if (q->dyn_type == DYN_LIMIT) \
650 q->parent->count--; \
651 DEB(printf("-- unlink entry 0x%08x %d -> 0x%08x %d, %d left\n", \
652 (q->id.src_ip), (q->id.src_port), \
653 (q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \
654 if (prev != NULL) \
655 prev->next = q = q->next ; \
656 else \
657 ipfw_dyn_v[i] = q = q->next ; \
658 dyn_count-- ; \
659 free(old_q, M_IPFW); }
660
661#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0)
662/**
663 * Remove all dynamic rules pointing to a given rule, or all
664 * rules if rule == NULL. Second parameter is 1 if we want to
665 * delete unconditionally, otherwise only expired rules are removed.
666 */
667static void
668remove_dyn_rule(struct ip_fw *rule, int force)
669{
670 struct ipfw_dyn_rule *prev, *q;
671 int i, pass, max_pass ;
672 static u_int32_t last_remove = 0 ;
673
674 if (ipfw_dyn_v == NULL || dyn_count == 0)
675 return ;
676 /* do not expire more than once per second, it is useless */
677 if (force == 0 && last_remove == time_second)
678 return ;
679 last_remove = time_second ;
680
681 /*
682 * because DYN_LIMIT refer to parent rules, during the first pass only
683 * remove child and mark any pending LIMIT_PARENT, and remove
684 * them in a second pass.
685 */
686 for (pass = max_pass = 0; pass <= max_pass ; pass++ ) {
687 for (i = 0 ; i < curr_dyn_buckets ; i++) {
688 for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) {
689 /*
690 * logic can become complex here, so we split tests.
691 * First, test if we match any rule,
692 * then make sure the rule is expired or we want to kill it,
693 * and possibly more in the future.
694 */
695 int zap = ( rule == NULL || rule == q->rule);
696 if (zap)
697 zap = force || TIME_LEQ( q->expire , time_second );
698 /* do not zap parent in first pass, record we need a second pass */
699 if (zap && q->dyn_type == DYN_LIMIT_PARENT) {
700 max_pass = 1; /* we need a second pass */
701 if (pass == 0 || q->count != 0) {
702 zap = 0 ;
703 if (pass == 1 && force) /* should not happen */
704 printf("OUCH! cannot remove rule, count %d\n",
705 q->count);
706 }
707 }
708 if (zap) {
709 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
710 } else {
711 prev = q ;
712 q = q->next ;
713 }
714 }
715 }
716 }
717}
718
719#define EXPIRE_DYN_CHAIN(rule) remove_dyn_rule(rule, 0 /* expired ones */)
720#define EXPIRE_DYN_CHAINS() remove_dyn_rule(NULL, 0 /* expired ones */)
721#define DELETE_DYN_CHAIN(rule) remove_dyn_rule(rule, 1 /* force removal */)
722#define DELETE_DYN_CHAINS() remove_dyn_rule(NULL, 1 /* force removal */)
723
724/**
725 * lookup a dynamic rule.
726 */
727static struct ipfw_dyn_rule *
728lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction)
729{
730 /*
731 * stateful ipfw extensions.
732 * Lookup into dynamic session queue
733 */
734 struct ipfw_dyn_rule *prev, *q ;
735 int i, dir = 0;
736#define MATCH_FORWARD 1
737
738 if (ipfw_dyn_v == NULL)
739 return NULL ;
740 i = hash_packet( pkt );
741 for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) {
742 if (q->dyn_type == DYN_LIMIT_PARENT)
743 goto next;
744 if (TIME_LEQ( q->expire , time_second ) ) { /* expire entry */
745 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
746 continue;
747 }
748 if ( pkt->proto == q->id.proto) {
749 if (pkt->src_ip == q->id.src_ip &&
750 pkt->dst_ip == q->id.dst_ip &&
751 pkt->src_port == q->id.src_port &&
752 pkt->dst_port == q->id.dst_port ) {
753 dir = MATCH_FORWARD ;
754 goto found ;
755 }
756 if (pkt->src_ip == q->id.dst_ip &&
757 pkt->dst_ip == q->id.src_ip &&
758 pkt->src_port == q->id.dst_port &&
759 pkt->dst_port == q->id.src_port ) {
760 dir = 0 ; /* reverse match */
761 goto found ;
762 }
763 }
764next:
765 prev = q ;
766 q = q->next ;
767 }
768 return NULL ; /* clearly not found */
769found:
770 if ( prev != NULL) { /* found and not in front */
771 prev->next = q->next ;
772 q->next = ipfw_dyn_v[i] ;
773 ipfw_dyn_v[i] = q ;
774 }
775 if (pkt->proto == IPPROTO_TCP) {
776 /* update state according to flags */
777 u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST);
778 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8);
779 switch (q->state) {
780 case TH_SYN :
781 /* opening */
782 q->expire = time_second + dyn_syn_lifetime ;
783 break ;
784 case TH_SYN | (TH_SYN << 8) :
785 /* move to established */
786 q->expire = time_second + dyn_ack_lifetime ;
787 break ;
788 case TH_SYN | (TH_SYN << 8) | TH_FIN :
789 case TH_SYN | (TH_SYN << 8) | (TH_FIN << 8) :
790 /* one side tries to close */
791 q->expire = time_second + dyn_ack_lifetime ;
792 break ;
793 case TH_SYN | (TH_SYN << 8) | TH_FIN | (TH_FIN << 8) :
794 /* both sides closed */
795 q->expire = time_second + dyn_fin_lifetime ;
796 break ;
797 default:
798#if 0
799 /*
800 * reset or some invalid combination, but can also
801 * occur if we use keep-state the wrong way.
802 */
803 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
804 printf("invalid state: 0x%x\n", q->state);
805#endif
806 q->expire = time_second + dyn_rst_lifetime ;
807 break ;
808 }
809 } else if (pkt->proto == IPPROTO_UDP) {
810 q->expire = time_second + dyn_udp_lifetime ;
811 } else {
812 /* other protocols */
813 q->expire = time_second + dyn_short_lifetime ;
814 }
815 if (match_direction)
816 *match_direction = dir ;
817 return q ;
818}
819
820/**
821 * Install state of type 'type' for a dynamic session.
822 * The hash table contains two type of rules:
823 * - regular rules (DYN_KEEP_STATE)
824 * - rules for sessions with limited number of sess per user
825 * (DYN_LIMIT). When they are created, the parent is
826 * increased by 1, and decreased on delete. In this case,
827 * the third parameter is the parent rule and not the chain.
828 * - "parent" rules for the above (DYN_LIMIT_PARENT).
829 */
830
831static struct ipfw_dyn_rule *
832add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule)
833{
834 struct ipfw_dyn_rule *r ;
835
836 int i ;
837 if (ipfw_dyn_v == NULL ||
838 (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) {
839 /* try reallocation, make sure we have a power of 2 */
840 u_int32_t i = dyn_buckets ;
841 while ( i > 0 && (i & 1) == 0 )
842 i >>= 1 ;
843 if (i != 1) /* not a power of 2 */
844 dyn_buckets = curr_dyn_buckets ; /* reset */
845 else {
846 curr_dyn_buckets = dyn_buckets ;
847 if (ipfw_dyn_v != NULL)
848 free(ipfw_dyn_v, M_IPFW);
849 ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof r,
850 M_IPFW, M_DONTWAIT | M_ZERO);
851 if (ipfw_dyn_v == NULL)
852 return NULL; /* failed ! */
853 }
854 }
855 i = hash_packet(id);
856
857 r = malloc(sizeof *r, M_IPFW, M_DONTWAIT | M_ZERO);
858 if (r == NULL) {
859 printf ("sorry cannot allocate state\n");
860 return NULL ;
861 }
862
863 /* increase refcount on parent, and set pointer */
864 if (dyn_type == DYN_LIMIT) {
865 struct ipfw_dyn_rule *parent = (struct ipfw_dyn_rule *)rule;
866 if ( parent->dyn_type != DYN_LIMIT_PARENT)
867 panic("invalid parent");
868 parent->count++ ;
869 r->parent = parent ;
870 rule = parent->rule;
871 }
872
873 r->id = *id ;
874 r->expire = time_second + dyn_syn_lifetime ;
875 r->rule = rule ;
876 r->dyn_type = dyn_type ;
877 r->pcnt = r->bcnt = 0 ;
878 r->count = 0 ;
879
880 r->bucket = i ;
881 r->next = ipfw_dyn_v[i] ;
882 ipfw_dyn_v[i] = r ;
883 dyn_count++ ;
884 DEB(printf("-- add entry 0x%08x %d -> 0x%08x %d, total %d\n",
885 (r->id.src_ip), (r->id.src_port),
886 (r->id.dst_ip), (r->id.dst_port),
887 dyn_count ); )
888 return r;
889}
890
891/**
892 * lookup dynamic parent rule using pkt and rule as search keys.
893 * If the lookup fails, then install one.
894 */
895static struct ipfw_dyn_rule *
896lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule)
897{
898 struct ipfw_dyn_rule *q;
899 int i;
900
901 if (ipfw_dyn_v) {
902 i = hash_packet( pkt );
903 for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next)
904 if (q->dyn_type == DYN_LIMIT_PARENT && rule == q->rule &&
905 pkt->proto == q->id.proto &&
906 pkt->src_ip == q->id.src_ip &&
907 pkt->dst_ip == q->id.dst_ip &&
908 pkt->src_port == q->id.src_port &&
909 pkt->dst_port == q->id.dst_port) {
910 q->expire = time_second + dyn_short_lifetime ;
911 DEB(printf("lookup_dyn_parent found 0x%p\n", q);)
912 return q;
913 }
914 }
915 return add_dyn_rule(pkt, DYN_LIMIT_PARENT, rule);
916}
917
918/*
919 * Install dynamic state.
920 * There are different types of dynamic rules which can be installed.
921 * The type is in rule->dyn_type.
922 * Type 0 (default) is a bidirectional rule
923 *
924 * Returns 1 (failure) if state is not installed because of errors or because
925 * session limitations are enforced.
926 */
927static int
928install_state(struct ip_fw *rule, struct ip_fw_args *args)
929{
930 struct ipfw_dyn_rule *q ;
931 static int last_log ;
932
933 u_int8_t type = rule->dyn_type ;
934
935 DEB(printf("-- install state type %d 0x%08x %u -> 0x%08x %u\n",
936 type,
937 (args->f_id.src_ip), (args->f_id.src_port),
938 (args->f_id.dst_ip), (args->f_id.dst_port) );)
939
940 q = lookup_dyn_rule(&args->f_id, NULL) ;
941 if (q != NULL) { /* should never occur */
942 if (last_log != time_second) {
943 last_log = time_second ;
944 printf(" entry already present, done\n");
945 }
946 return 0 ;
947 }
948 if (dyn_count >= dyn_max) /* try remove old ones... */
949 EXPIRE_DYN_CHAINS();
950 if (dyn_count >= dyn_max) {
951 if (last_log != time_second) {
952 last_log = time_second ;
953 printf(" Too many dynamic rules, sorry\n");
954 }
955 return 1; /* cannot install, notify caller */
956 }
957
958 switch (type) {
959 case DYN_KEEP_STATE: /* bidir rule */
960 add_dyn_rule(&args->f_id, DYN_KEEP_STATE, rule);
961 break ;
962 case DYN_LIMIT: /* limit number of sessions */
963 {
964 u_int16_t limit_mask = rule->limit_mask ;
965 u_int16_t conn_limit = rule->conn_limit ;
966 struct ipfw_flow_id id;
967 struct ipfw_dyn_rule *parent;
968
969 DEB(printf("installing dyn-limit rule %d\n", conn_limit);)
970
971 id.dst_ip = id.src_ip = 0;
972 id.dst_port = id.src_port = 0 ;
973 id.proto = args->f_id.proto ;
974
975 if (limit_mask & DYN_SRC_ADDR)
976 id.src_ip = args->f_id.src_ip;
977 if (limit_mask & DYN_DST_ADDR)
978 id.dst_ip = args->f_id.dst_ip;
979 if (limit_mask & DYN_SRC_PORT)
980 id.src_port = args->f_id.src_port;
981 if (limit_mask & DYN_DST_PORT)
982 id.dst_port = args->f_id.dst_port;
983 parent = lookup_dyn_parent(&id, rule);
984 if (parent == NULL) {
985 printf("add parent failed\n");
986 return 1;
987 }
988 if (parent->count >= conn_limit) {
989 EXPIRE_DYN_CHAIN(rule); /* try to expire some */
990 /*
991 * The expiry might have removed the parent too.
992 * We lookup again, which will re-create if necessary.
993 */
994 parent = lookup_dyn_parent(&id, rule);
995 if (parent == NULL) {
996 printf("add parent failed\n");
997 return 1;
998 }
999 if (parent->count >= conn_limit) {
1000 if (fw_verbose && last_log != time_second) {
1001 last_log = time_second;
1002 log(LOG_SECURITY | LOG_DEBUG,
1003 "drop session, too many entries\n");
1004 }
1005 return 1;
1006 }
1007 }
1008 add_dyn_rule(&args->f_id, DYN_LIMIT, (struct ip_fw *)parent);
1009 }
1010 break ;
1011 default:
1012 printf("unknown dynamic rule type %u\n", type);
1013 return 1 ;
1014 }
1015 lookup_dyn_rule(&args->f_id, NULL) ; /* XXX just set the lifetime */
1016 return 0;
1017}
1018
1019/*
1020 * given an ip_fw *, lookup_next_rule will return a pointer
1021 * of the same type to the next one. This can be either the jump
1022 * target (for skipto instructions) or the next one in the list (in
1023 * all other cases including a missing jump target).
1024 * Backward jumps are not allowed, so start looking from the next
1025 * rule...
1026 */
1027static struct ip_fw * lookup_next_rule(struct ip_fw *me);
1028
1029static struct ip_fw *
1030lookup_next_rule(struct ip_fw *me)
1031{
1032 struct ip_fw *rule ;
1033 int rulenum = me->fw_skipto_rule ; /* guess... */
1034
1035 if ( (me->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_SKIPTO )
1036 for (rule = LIST_NEXT(me,next); rule ; rule = LIST_NEXT(rule,next))
1037 if (rule->fw_number >= rulenum)
1038 return rule ;
1039 return LIST_NEXT(me,next) ; /* failure or not a skipto */
1040}
1041
1042/*
1043 * Parameters:
1044 *
1045 * *m The packet; we set to NULL when/if we nuke it.
1046 * oif Outgoing interface, or NULL if packet is incoming
1047 * *cookie Skip up to the first rule past this rule number;
1048 * upon return, non-zero port number for divert or tee.
1049 * Special case: cookie == NULL on input for bridging.
1050 * *flow_id pointer to the last matching rule (in/out)
1051 * *next_hop socket we are forwarding to (in/out).
1052 *
1053 * Return value:
1054 *
1055 * IP_FW_PORT_DENY_FLAG the packet must be dropped.
1056 * 0 The packet is to be accepted and routed normally OR
1057 * the packet was denied/rejected and has been dropped;
1058 * in the latter case, *m is equal to NULL upon return.
1059 * port Divert the packet to port, with these caveats:
1060 *
1061 * - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead
1062 * of diverting it (ie, 'ipfw tee').
1063 *
1064 * - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower
1065 * 16 bits as a dummynet pipe number instead of diverting
1066 */
1067
1068static int
1069ip_fw_chk(struct ip_fw_args *args)
1070{
1071 /*
1072 * grab things into variables to minimize diffs.
1073 * XXX this has to be cleaned up later.
1074 */
1075 struct mbuf **m = &(args->m);
1076 struct ifnet *oif = args->oif;
1077 u_int16_t *cookie = &(args->divert_rule);
1078 struct ip_fw **flow_id = &(args->rule);
1079 struct sockaddr_in **next_hop = &(args->next_hop);
1080
1081 struct ip_fw *f = NULL; /* matching rule */
1082 struct ip *ip = mtod(*m, struct ip *);
1083 struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
1084 struct ifnet *tif;
1085 u_int hlen = 0;
1086
1087 u_short ip_off=0, offset = 0;
1088 /* local copy of addresses for faster matching */
1089 u_short src_port = 0, dst_port = 0;
1090 struct in_addr src_ip, dst_ip;
1091 u_int8_t proto= 0, flags = 0;
1092 u_int16_t skipto;
1093 u_int16_t ip_len=0;
1094
1095 int dyn_checked = 0 ; /* set after dyn.rules have been checked. */
1096 int direction = MATCH_FORWARD ; /* dirty trick... */
1097 struct ipfw_dyn_rule *q = NULL ;
1098
1099 /* Special hack for bridging (as usual) */
1100#define BRIDGED (args->eh != NULL)
1101 if (BRIDGED) { /* this is a bridged packet */
1102 if ( (*m)->m_pkthdr.len >= sizeof(struct ip) &&
1103 ntohs(args->eh->ether_type) == ETHERTYPE_IP)
1104 hlen = ip->ip_hl << 2;
1105 else
1106 return 0; /* XXX ipfw1 always accepts non-ip pkts */
1107 } else
1108 hlen = ip->ip_hl << 2;
1109
1110 /* Grab and reset cookie */
1111 skipto = *cookie;
1112 *cookie = 0;
1113
1114#define PULLUP_TO(len) do { \
1115 if ((*m)->m_len < (len)) { \
1116 if ((*m = m_pullup(*m, (len))) == 0) \
1117 goto bogusfrag; \
1118 ip = mtod(*m, struct ip *); \
1119 } \
1120 } while (0)
1121
1122 if (hlen > 0) { /* this is an IP packet */
1123 /*
1124 * Collect parameters into local variables for faster matching.
1125 */
1126 proto = ip->ip_p;
1127 src_ip = ip->ip_src;
1128 dst_ip = ip->ip_dst;
1129 if (BRIDGED) { /* bridged packets are as on the wire */
1130 ip_off = ntohs(ip->ip_off);
1131 ip_len = ntohs(ip->ip_len);
1132 } else {
1133 ip_off = ip->ip_off;
1134 ip_len = ip->ip_len;
1135 }
1136 offset = ip_off & IP_OFFMASK;
1137 if (offset == 0) {
1138 switch (proto) {
1139 case IPPROTO_TCP : {
1140 struct tcphdr *tcp;
1141
1142 PULLUP_TO(hlen + sizeof(struct tcphdr));
1143 tcp =(struct tcphdr *)((u_int32_t *)ip + ip->ip_hl);
1144 dst_port = tcp->th_dport ;
1145 src_port = tcp->th_sport ;
1146 flags = tcp->th_flags ;
1147 }
1148 break ;
1149
1150 case IPPROTO_UDP : {
1151 struct udphdr *udp;
1152
1153 PULLUP_TO(hlen + sizeof(struct udphdr));
1154 udp =(struct udphdr *)((u_int32_t *)ip + ip->ip_hl);
1155 dst_port = udp->uh_dport ;
1156 src_port = udp->uh_sport ;
1157 }
1158 break;
1159
1160 case IPPROTO_ICMP:
1161 PULLUP_TO(hlen + 4); /* type, code and checksum. */
1162 flags = ((struct icmp *)
1163 ((u_int32_t *)ip + ip->ip_hl))->icmp_type ;
1164 break ;
1165
1166 default :
1167 break;
1168 }
1169 }
1170 }
1171#undef PULLUP_TO
1172 args->f_id.src_ip = ntohl(src_ip.s_addr);
1173 args->f_id.dst_ip = ntohl(dst_ip.s_addr);
1174 args->f_id.proto = proto;
1175 args->f_id.src_port = ntohs(src_port);
1176 args->f_id.dst_port = ntohs(dst_port);
1177 args->f_id.flags = flags;
1178
1179 if (*flow_id) {
1180 /*
1181 * Packet has already been tagged. Look for the next rule
1182 * to restart processing.
1183 */
1184 if (fw_one_pass) /* just accept if fw_one_pass is set */
1185 return 0;
1186
1187 f = (*flow_id)->next_rule_ptr ;
1188 if (f == NULL)
1189 f = (*flow_id)->next_rule_ptr = lookup_next_rule(*flow_id);
1190 if (f == NULL)
1191 goto dropit;
1192 } else {
1193 /*
1194 * Go down the list, looking for enlightment.
1195 * If we've been asked to start at a given rule, do so.
1196 */
1197 f = LIST_FIRST(&ip_fw_chain_head);
1198 if (skipto != 0) {
1199 if (skipto >= IPFW_DEFAULT_RULE)
1200 goto dropit;
1201 while (f && f->fw_number <= skipto)
1202 f = LIST_NEXT(f, next);
1203 if (f == NULL)
1204 goto dropit;
1205 }
1206 }
1207
1208 for (; f; f = LIST_NEXT(f, next)) {
1209again:
1210 if (f->fw_number == IPFW_DEFAULT_RULE)
1211 goto got_match ;
1212
1213 /*
1214 * dynamic rules are checked at the first keep-state or
1215 * check-state occurrence.
1216 */
1217 if (f->fw_flg & (IP_FW_F_KEEP_S|IP_FW_F_CHECK_S) &&
1218 dyn_checked == 0 ) {
1219 dyn_checked = 1 ;
1220 q = lookup_dyn_rule(&args->f_id, &direction);
1221 if (q != NULL) {
1222 DEB(printf("-- dynamic match 0x%08x %d %s 0x%08x %d\n",
1223 (q->id.src_ip), (q->id.src_port),
1224 (direction == MATCH_FORWARD ? "-->" : "<--"),
1225 (q->id.dst_ip), (q->id.dst_port) ); )
1226 f = q->rule ;
1227 q->pcnt++ ;
1228 q->bcnt += ip_len;
1229 goto got_match ; /* random not allowed here */
1230 }
1231 /* if this was a check-only rule, continue with next */
1232 if (f->fw_flg & IP_FW_F_CHECK_S)
1233 continue ;
1234 }
1235
1236 /* Check if rule only valid for bridged packets */
1237 if ((f->fw_flg & IP_FW_BRIDGED) != 0 && !(BRIDGED))
1238 continue;
1239
1240 if (oif) {
1241 /* Check direction outbound */
1242 if (!(f->fw_flg & IP_FW_F_OUT))
1243 continue;
1244 } else {
1245 /* Check direction inbound */
1246 if (!(f->fw_flg & IP_FW_F_IN))
1247 continue;
1248 }
1249
1250 /* Fragments */
1251 if ((f->fw_flg & IP_FW_F_FRAG) && offset == 0 )
1252 continue;
1253
1254 if (f->fw_flg & IP_FW_F_SME) {
1255 INADDR_TO_IFP(src_ip, tif);
1256 if (tif == NULL)
1257 continue;
1258 }
1259 if (f->fw_flg & IP_FW_F_DME) {
1260 INADDR_TO_IFP(dst_ip, tif);
1261 if (tif == NULL)
1262 continue;
1263 }
1264 /* If src-addr doesn't match, not this rule. */
1265 if (((f->fw_flg & IP_FW_F_INVSRC) != 0) ^ ((src_ip.s_addr
1266 & f->fw_smsk.s_addr) != f->fw_src.s_addr))
1267 continue;
1268
1269 /* If dest-addr doesn't match, not this rule. */
1270 if (((f->fw_flg & IP_FW_F_INVDST) != 0) ^ ((dst_ip.s_addr
1271 & f->fw_dmsk.s_addr) != f->fw_dst.s_addr))
1272 continue;
1273
1274 /* Interface check */
1275 if ((f->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
1276 struct ifnet *const iface = oif ? oif : rif;
1277
1278 /* Backwards compatibility hack for "via" */
1279 if (!iface || !iface_match(iface,
1280 &f->fw_in_if, f->fw_flg & IP_FW_F_OIFNAME))
1281 continue;
1282 } else {
1283 /* Check receive interface */
1284 if ((f->fw_flg & IP_FW_F_IIFACE)
1285 && (!rif || !iface_match(rif,
1286 &f->fw_in_if, f->fw_flg & IP_FW_F_IIFNAME)))
1287 continue;
1288 /* Check outgoing interface */
1289 if ((f->fw_flg & IP_FW_F_OIFACE)
1290 && (!oif || !iface_match(oif,
1291 &f->fw_out_if, f->fw_flg & IP_FW_F_OIFNAME)))
1292 continue;
1293 }
1294
1295 /* Check IP options */
1296 if (f->fw_ipopt != f->fw_ipnopt && !ipopts_match(ip, f))
1297 continue;
1298
1299 /* Check protocol; if wildcard, and no [ug]id, match */
1300 if (f->fw_prot == IPPROTO_IP) {
1301 if (!(f->fw_flg & (IP_FW_F_UID|IP_FW_F_GID)))
1302 goto rnd_then_got_match;
1303 } else
1304 /* If different, don't match */
1305 if (proto != f->fw_prot)
1306 continue;
1307
1308 /* Protocol specific checks for uid only */
1309 if (f->fw_flg & (IP_FW_F_UID|IP_FW_F_GID)) {
1310 switch (proto) {
1311 case IPPROTO_TCP:
1312 {
1313 struct inpcb *P;
1314
1315 if (offset == 1) /* cf. RFC 1858 */
1316 goto bogusfrag;
1317 if (offset != 0)
1318 continue;
1319
1320 if (oif)
1321 P = in_pcblookup_hash(&tcbinfo, dst_ip,
1322 dst_port, src_ip, src_port, 0,
1323 oif);
1324 else
1325 P = in_pcblookup_hash(&tcbinfo, src_ip,
1326 src_port, dst_ip, dst_port, 0,
1327 NULL);
1328
1329 if (P && P->inp_socket) {
1330 if (f->fw_flg & IP_FW_F_UID) {
1331 if (P->inp_socket->so_cred->cr_uid !=
1332 f->fw_uid)
1333 continue;
1334 } else if (!groupmember(f->fw_gid,
1335 P->inp_socket->so_cred))
1336 continue;
1337 } else
1338 continue;
1339 break;
1340 }
1341
1342 case IPPROTO_UDP:
1343 {
1344 struct inpcb *P;
1345
1346 if (offset != 0)
1347 continue;
1348
1349 if (oif)
1350 P = in_pcblookup_hash(&udbinfo, dst_ip,
1351 dst_port, src_ip, src_port, 1,
1352 oif);
1353 else
1354 P = in_pcblookup_hash(&udbinfo, src_ip,
1355 src_port, dst_ip, dst_port, 1,
1356 NULL);
1357
1358 if (P && P->inp_socket) {
1359 if (f->fw_flg & IP_FW_F_UID) {
1360 if (P->inp_socket->so_cred->cr_uid !=
1361 f->fw_uid)
1362 continue;
1363 } else if (!groupmember(f->fw_gid,
1364 P->inp_socket->so_cred))
1365 continue;
1366 } else
1367 continue;
1368 break;
1369 }
1370
1371 default:
1372 continue;
1373 }
1374 }
1375
1376 /* Protocol specific checks */
1377 switch (proto) {
1378 case IPPROTO_TCP:
1379 {
1380 struct tcphdr *tcp;
1381
1382 if (offset == 1) /* cf. RFC 1858 */
1383 goto bogusfrag;
1384 if (offset != 0) {
1385 /*
1386 * TCP flags and ports aren't available in this
1387 * packet -- if this rule specified either one,
1388 * we consider the rule a non-match.
1389 */
1390 if (IP_FW_HAVEPORTS(f) != 0 ||
1391 f->fw_tcpopt != f->fw_tcpnopt ||
1392 f->fw_tcpf != f->fw_tcpnf)
1393 continue;
1394
1395 break;
1396 }
1397 tcp = (struct tcphdr *) ((u_int32_t *)ip + ip->ip_hl);
1398
1399 if (f->fw_tcpopt != f->fw_tcpnopt && !tcpopts_match(tcp, f))
1400 continue;
1401 if (((f->fw_tcpf != f->fw_tcpnf) ||
1402 (f->fw_ipflg & IP_FW_IF_TCPEST)) &&
1403 !tcpflg_match(tcp, f))
1404 continue;
1405 goto check_ports;
1406 }
1407
1408 case IPPROTO_UDP:
1409 if (offset != 0) {
1410 /*
1411 * Port specification is unavailable -- if this
1412 * rule specifies a port, we consider the rule
1413 * a non-match.
1414 */
1415 if (IP_FW_HAVEPORTS(f) )
1416 continue;
1417
1418 break;
1419 }
1420check_ports:
1421 if (!port_match(&f->fw_uar.fw_pts[0],
1422 IP_FW_GETNSRCP(f), ntohs(src_port),
1423 f->fw_flg & IP_FW_F_SRNG,
1424 f->fw_flg & IP_FW_F_SMSK))
1425 continue;
1426 if (!port_match(&f->fw_uar.fw_pts[IP_FW_GETNSRCP(f)],
1427 IP_FW_GETNDSTP(f), ntohs(dst_port),
1428 f->fw_flg & IP_FW_F_DRNG,
1429 f->fw_flg & IP_FW_F_DMSK))
1430 continue;
1431 break;
1432
1433 case IPPROTO_ICMP:
1434 {
1435 struct icmp *icmp;
1436
1437 if (offset != 0) /* Type isn't valid */
1438 break;
1439 icmp = (struct icmp *) ((u_int32_t *)ip + ip->ip_hl);
1440 if (!icmptype_match(icmp, f))
1441 continue;
1442 break;
1443 }
1444
1445 default:
1446 break;
1447
1448bogusfrag:
1449 if (fw_verbose) {
1450 if (m != NULL)
1451 ipfw_report(NULL, ip, ip_off, ip_len, rif, oif);
1452 else
1453 printf("pullup failed\n");
1454 }
1455 goto dropit;
1456
1457 }
1458
1459rnd_then_got_match:
1460 if ( f->dont_match_prob && random() < f->dont_match_prob )
1461 continue ;
1462got_match:
1463 /*
1464 * If not a dynamic match (q == NULL) and keep-state, install
1465 * a new dynamic entry.
1466 */
1467 if (q == NULL && f->fw_flg & IP_FW_F_KEEP_S) {
1468 if (install_state(f, args)) /* error or limit violation */
1469 goto dropit;
1470 }
1471 /* Update statistics */
1472 f->fw_pcnt += 1;
1473 f->fw_bcnt += ip_len;
1474 f->timestamp = time_second;
1475
1476 /* Log to console if desired */
1477 if ((f->fw_flg & IP_FW_F_PRN) && fw_verbose && hlen > 0)
1478 ipfw_report(f, ip, offset, ip_len, rif, oif);
1479
1480 /* Take appropriate action */
1481 switch (f->fw_flg & IP_FW_F_COMMAND) {
1482 case IP_FW_F_ACCEPT:
1483 return(0);
1484 case IP_FW_F_COUNT:
1485 continue;
1486#ifdef IPDIVERT
1487 case IP_FW_F_DIVERT:
1488 *cookie = f->fw_number;
1489 return(f->fw_divert_port);
1490 case IP_FW_F_TEE:
1491 *cookie = f->fw_number;
1492 return(f->fw_divert_port | IP_FW_PORT_TEE_FLAG);
1493#endif
1494 case IP_FW_F_SKIPTO: /* XXX check */
1495 if (f->next_rule_ptr == NULL)
1496 f->next_rule_ptr = lookup_next_rule(f) ;
1497 f = f->next_rule_ptr;
1498 if (!f)
1499 goto dropit;
1500 goto again ;
1501
1502 case IP_FW_F_PIPE:
1503 case IP_FW_F_QUEUE:
1504 *flow_id = f ; /* XXX set flow id */
1505 return(f->fw_pipe_nr | IP_FW_PORT_DYNT_FLAG);
1506
1507 case IP_FW_F_FWD:
1508 /* Change the next-hop address for this packet.
1509 * Initially we'll only worry about directly
1510 * reachable next-hop's, but ultimately
1511 * we will work out for next-hops that aren't
1512 * direct the route we would take for it. We
1513 * [cs]ould leave this latter problem to
1514 * ip_output.c. We hope to high [name the abode of
1515 * your favourite deity] that ip_output doesn't modify
1516 * the new value of next_hop (which is dst there)
1517 * XXX warning-- there is a dangerous reference here
1518 * from next_hop to a field within the rule. If the
1519 * rule is deleted, weird things might occur.
1520 */
1521 if (next_hop != NULL /* Make sure, first... */
1522 && (q == NULL || direction == MATCH_FORWARD) )
1523 *next_hop = &(f->fw_fwd_ip);
1524 return(0); /* Allow the packet */
1525
1526 }
1527
1528 /* Deny/reject this packet using this rule */
1529 break;
1530 }
1531
1532 /* Rule IPFW_DEFAULT_RULE should always be there and match */
1533 KASSERT(f != NULL, ("ip_fw: no chain"));
1534
1535 /*
1536 * At this point, we're going to drop the packet.
1537 * Send a reject notice if all of the following are true:
1538 *
1539 * - The packet matched a reject rule
1540 * - The packet is not an ICMP packet, or is an ICMP query packet
1541 * - The packet is not a multicast or broadcast packet
1542 */
1543 if ((f->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_REJECT
1544 && (proto != IPPROTO_ICMP || is_icmp_query(ip))
1545 && !((*m)->m_flags & (M_BCAST|M_MCAST))
1546 && !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
1547 /* Must convert to host order for icmp_error() etc. */
1548 if (BRIDGED) {
1549 ip->ip_len = ntohs(ip->ip_len);
1550 ip->ip_off = ntohs(ip->ip_off);
1551 }
1552 switch (f->fw_reject_code) {
1553 case IP_FW_REJECT_RST:
1554 {
1555 /* XXX warning, this code writes into the mbuf */
1556 struct tcphdr *const tcp =
1557 (struct tcphdr *) ((u_int32_t *)ip + ip->ip_hl);
1558 struct tcpiphdr ti, *const tip = (struct tcpiphdr *) ip;
1559
1560 if (offset != 0 || (tcp->th_flags & TH_RST))
1561 break;
1562 ti.ti_i = *((struct ipovly *) ip);
1563 ti.ti_t = *tcp;
1564 bcopy(&ti, ip, sizeof(ti));
1565 NTOHL(tip->ti_seq);
1566 NTOHL(tip->ti_ack);
1567 tip->ti_len = ip_len - hlen - (tip->ti_off << 2);
1568 if (tcp->th_flags & TH_ACK) {
1569 tcp_respond(NULL, (void *)ip, tcp, *m,
1570 (tcp_seq)0, tcp->th_ack, TH_RST);
1571 } else {
1572 if (tcp->th_flags & TH_SYN)
1573 tip->ti_len++;
1574 tcp_respond(NULL, (void *)ip, tcp, *m,
1575 tip->ti_seq + tip->ti_len,
1576 (tcp_seq)0, TH_RST|TH_ACK);
1577 }
1578 *m = NULL;
1579 break;
1580 }
1581 default: /* Send an ICMP unreachable using code */
1582 icmp_error(*m, ICMP_UNREACH,
1583 f->fw_reject_code, 0L, 0);
1584 *m = NULL;
1585 break;
1586 }
1587 }
1588
1589dropit:
1590 /*
1591 * Finally, drop the packet.
1592 */
1593 return(IP_FW_PORT_DENY_FLAG);
1594#undef BRIDGED
1595}
1596
1597/*
1598 * when a rule is added/deleted, zero the direct pointers within
1599 * all firewall rules. These will be reconstructed on the fly
1600 * as packets are matched.
1601 * Must be called at splimp().
1602 */
1603static void
1604flush_rule_ptrs()
1605{
1606 struct ip_fw *fcp ;
1607
1608 LIST_FOREACH(fcp, &ip_fw_chain_head, next) {
1609 fcp->next_rule_ptr = NULL ;
1610 }
1611}
1612
1613void
1614flush_pipe_ptrs(struct dn_flow_set *match)
1615{
1616 struct ip_fw *fcp ;
1617
1618 LIST_FOREACH(fcp, &ip_fw_chain_head, next) {
1619 if (match == NULL || fcp->pipe_ptr == match)
1620 fcp->pipe_ptr = NULL;
1621 }
1622}
1623
1624static int
1625add_entry(struct ip_fw_head *head, struct ip_fw *rule)
1626{
1627 struct ip_fw *ftmp, *fcp, *fcpl;
1628 u_short nbr = 0;
1629 int s;
1630
1631 ftmp = malloc(sizeof *ftmp, M_IPFW, M_DONTWAIT | M_ZERO);
1632 if (!ftmp)
1633 return (ENOSPC);
1634 bcopy(rule, ftmp, sizeof(*ftmp));
1635
1636 ftmp->fw_in_if.fu_via_if.name[FW_IFNLEN - 1] = '\0';
1637 ftmp->fw_pcnt = 0L;
1638 ftmp->fw_bcnt = 0L;
1639 ftmp->next_rule_ptr = NULL ;
1640 ftmp->pipe_ptr = NULL ;
1641
1642 s = splimp();
1643
1644 if (LIST_FIRST(head) == 0) {
1645 LIST_INSERT_HEAD(head, ftmp, next);
1646 goto done;
1647 }
1648
1649 /* If entry number is 0, find highest numbered rule and add 100 */
1650 if (ftmp->fw_number == 0) {
1651 LIST_FOREACH(fcp, head, next) {
1652 if (fcp->fw_number != IPFW_DEFAULT_RULE)
1653 nbr = fcp->fw_number;
1654 else
1655 break;
1656 }
1657 if (nbr < IPFW_DEFAULT_RULE - 100)
1658 nbr += 100;
1659 ftmp->fw_number = rule->fw_number = nbr;
1660 }
1661
1662 /* Got a valid number; now insert it, keeping the list ordered */
1663 fcpl = NULL ;
1664 LIST_FOREACH(fcp, head, next) {
1665 if (fcp->fw_number > ftmp->fw_number) {
1666 if (fcpl) {
1667 LIST_INSERT_AFTER(fcpl, ftmp, next);
1668 } else {
1669 LIST_INSERT_HEAD(head, ftmp, next);
1670 }
1671 break;
1672 } else {
1673 fcpl = fcp;
1674 }
1675 }
1676 flush_rule_ptrs();
1677done:
1678 static_count++;
1679 splx(s);
1680 DEB(printf("++ installed rule %d, static count now %d\n",
1681 ftmp->fw_number, static_count);)
1682 return (0);
1683}
1684
1685/**
1686 * free storage associated with a static rule entry (including
1687 * dependent dynamic rules), and zeroes rule pointers to avoid
1688 * dangling pointer dereferences.
1689 * @return a pointer to the next entry.
1690 * Must be called at splimp() and with a non-null argument.
1691 */
1692static struct ip_fw *
1693free_chain(struct ip_fw *fcp)
1694{
1695 struct ip_fw *n;
1696
1697 n = LIST_NEXT(fcp, next);
1698 DELETE_DYN_CHAIN(fcp);
1699 LIST_REMOVE(fcp, next);
1700 static_count--;
1701 if (DUMMYNET_LOADED)
1702 ip_dn_ruledel_ptr(fcp) ;
1703 flush_rule_ptrs(); /* more efficient to do outside the loop */
1704 free(fcp, M_IPFW);
1705 return n;
1706}
1707
1708/**
1709 * remove all rules with given number.
1710 */
1711static int
1712del_entry(struct ip_fw_head *chainptr, u_short number)
1713{
1714 struct ip_fw *rule;
1715
1716 if (number != IPFW_DEFAULT_RULE) {
1717 LIST_FOREACH(rule, chainptr, next) {
1718 if (rule->fw_number == number) {
1719 int s ;
1720
1721 s = splimp(); /* prevent access to rules while removing */
1722 while (rule && rule->fw_number == number)
1723 rule = free_chain(rule);
1724 /* XXX could move flush_rule_ptrs() here */
1725 splx(s);
1726 return 0 ;
1727 }
1728 }
1729 }
1730 return (EINVAL);
1731}
1732
1733/**
1734 * Reset some or all counters on firewall rules.
1735 * @arg frwl is null to clear all entries, or contains a specific
1736 * rule number.
1737 * @arg log_only is 1 if we only want to reset logs, zero otherwise.
1738 */
1739
1740static int
1741zero_entry(struct ip_fw *frwl, int log_only)
1742{
1743 struct ip_fw *rule;
1744 int s;
1745 u_short number = 0 ;
1746 char *msg ;
1747
1748 if (frwl == 0) {
1749 s = splimp();
1750 LIST_FOREACH(rule, &ip_fw_chain_head, next) {
1751 if (log_only == 0) {
1752 rule->fw_bcnt = rule->fw_pcnt = 0;
1753 rule->timestamp = 0;
1754 }
1755 rule->fw_loghighest = rule->fw_pcnt+rule->fw_logamount;
1756 }
1757 splx(s);
1758 msg = log_only ? "ipfw: All logging counts cleared.\n" :
1759 "ipfw: Accounting cleared.\n";
1760 } else {
1761 int cleared = 0;
1762 number = frwl->fw_number ;
1763 /*
1764 * It is possible to insert multiple chain entries with the
1765 * same number, so we don't stop after finding the first
1766 * match if zeroing a specific entry.
1767 */
1768 LIST_FOREACH(rule, &ip_fw_chain_head, next)
1769 if (number == rule->fw_number) {
1770 s = splimp();
1771 while (rule && number == rule->fw_number) {
1772 if (log_only == 0) {
1773 rule->fw_bcnt = rule->fw_pcnt = 0;
1774 rule->timestamp = 0;
1775 }
1776 rule->fw_loghighest = rule->fw_pcnt+ rule->fw_logamount;
1777 rule = LIST_NEXT(rule, next);
1778 }
1779 splx(s);
1780 cleared = 1;
1781 break;
1782 }
1783 if (!cleared) /* we did not find any matching rules */
1784 return (EINVAL);
1785 msg = log_only ? "ipfw: Entry %d logging count reset.\n" :
1786 "ipfw: Entry %d cleared.\n";
1787 }
1788 if (fw_verbose)
1789 log(LOG_SECURITY | LOG_NOTICE, msg, number);
1790 return (0);
1791}
1792
1793static int
1794check_ipfw_struct(struct ip_fw *frwl)
1795{
1796 /* Check for invalid flag bits */
1797 if ((frwl->fw_flg & ~IP_FW_F_MASK) != 0) {
1798 dprintf(("%s undefined flag bits set (flags=%x)\n",
1799 err_prefix, frwl->fw_flg));
1800 return (EINVAL);
1801 }
1802 if (frwl->fw_flg == IP_FW_F_CHECK_S) {
1803 /* check-state */
1804 return 0 ;
1805 }
1806 /* Must apply to incoming or outgoing (or both) */
1807 if (!(frwl->fw_flg & (IP_FW_F_IN | IP_FW_F_OUT))) {
1808 dprintf(("%s neither in nor out\n", err_prefix));
1809 return (EINVAL);
1810 }
1811 /* Empty interface name is no good */
1812 if (((frwl->fw_flg & IP_FW_F_IIFNAME)
1813 && !*frwl->fw_in_if.fu_via_if.name)
1814 || ((frwl->fw_flg & IP_FW_F_OIFNAME)
1815 && !*frwl->fw_out_if.fu_via_if.name)) {
1816 dprintf(("%s empty interface name\n", err_prefix));
1817 return (EINVAL);
1818 }
1819 /* Sanity check interface matching */
1820 if ((frwl->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
1821 ; /* allow "via" backwards compatibility */
1822 } else if ((frwl->fw_flg & IP_FW_F_IN)
1823 && (frwl->fw_flg & IP_FW_F_OIFACE)) {
1824 dprintf(("%s outgoing interface check on incoming\n",
1825 err_prefix));
1826 return (EINVAL);
1827 }
1828 /* Sanity check port ranges */
1829 if ((frwl->fw_flg & IP_FW_F_SRNG) && IP_FW_GETNSRCP(frwl) < 2) {
1830 dprintf(("%s src range set but n_src_p=%d\n",
1831 err_prefix, IP_FW_GETNSRCP(frwl)));
1832 return (EINVAL);
1833 }
1834 if ((frwl->fw_flg & IP_FW_F_DRNG) && IP_FW_GETNDSTP(frwl) < 2) {
1835 dprintf(("%s dst range set but n_dst_p=%d\n",
1836 err_prefix, IP_FW_GETNDSTP(frwl)));
1837 return (EINVAL);
1838 }
1839 if (IP_FW_GETNSRCP(frwl) + IP_FW_GETNDSTP(frwl) > IP_FW_MAX_PORTS) {
1840 dprintf(("%s too many ports (%d+%d)\n",
1841 err_prefix, IP_FW_GETNSRCP(frwl), IP_FW_GETNDSTP(frwl)));
1842 return (EINVAL);
1843 }
1844 /*
1845 * Protocols other than TCP/UDP don't use port range
1846 */
1847 if ((frwl->fw_prot != IPPROTO_TCP) &&
1848 (frwl->fw_prot != IPPROTO_UDP) &&
1849 (IP_FW_GETNSRCP(frwl) || IP_FW_GETNDSTP(frwl))) {
1850 dprintf(("%s port(s) specified for non TCP/UDP rule\n",
1851 err_prefix));
1852 return (EINVAL);
1853 }
1854
1855 /*
1856 * Rather than modify the entry to make such entries work,
1857 * we reject this rule and require user level utilities
1858 * to enforce whatever policy they deem appropriate.
1859 */
1860 if ((frwl->fw_src.s_addr & (~frwl->fw_smsk.s_addr)) ||
1861 (frwl->fw_dst.s_addr & (~frwl->fw_dmsk.s_addr))) {
1862 dprintf(("%s rule never matches\n", err_prefix));
1863 return (EINVAL);
1864 }
1865
1866 if ((frwl->fw_flg & IP_FW_F_FRAG) &&
1867 (frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
1868 if (IP_FW_HAVEPORTS(frwl)) {
1869 dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
1870 return (EINVAL);
1871 }
1872 if (frwl->fw_prot == IPPROTO_TCP &&
1873 frwl->fw_tcpf != frwl->fw_tcpnf) {
1874 dprintf(("%s cannot mix 'frag' and TCP flags\n", err_prefix));
1875 return (EINVAL);
1876 }
1877 }
1878
1879 /* Check command specific stuff */
1880 switch (frwl->fw_flg & IP_FW_F_COMMAND) {
1881 case IP_FW_F_REJECT:
1882 if (frwl->fw_reject_code >= 0x100
1883 && !(frwl->fw_prot == IPPROTO_TCP
1884 && frwl->fw_reject_code == IP_FW_REJECT_RST)) {
1885 dprintf(("%s unknown reject code\n", err_prefix));
1886 return (EINVAL);
1887 }
1888 break;
1889#ifdef IPDIVERT
1890 case IP_FW_F_DIVERT: /* Diverting to port zero is invalid */
1891 case IP_FW_F_TEE:
1892#endif
1893 case IP_FW_F_PIPE: /* pipe 0 is invalid */
1894 case IP_FW_F_QUEUE: /* queue 0 is invalid */
1895 if (frwl->fw_divert_port == 0) {
1896 dprintf(("%s 0 is an invalid argument\n", err_prefix));
1897 return (EINVAL);
1898 }
1899 break;
1900 case IP_FW_F_DENY:
1901 case IP_FW_F_ACCEPT:
1902 case IP_FW_F_COUNT:
1903 case IP_FW_F_SKIPTO:
1904 case IP_FW_F_FWD:
1905 case IP_FW_F_UID:
1906 case IP_FW_F_GID:
1907 break;
1908 default:
1909 dprintf(("%s invalid command\n", err_prefix));
1910 return (EINVAL);
1911 }
1912
1913 return 0;
1914}
1915
1916static int
1917ip_fw_ctl(struct sockopt *sopt)
1918{
1919 int error, s;
1920 size_t size;
1921 struct ip_fw *fcp;
1922 struct ip_fw frwl, *bp , *buf;
1923
1924 /*
1925 * Disallow modifications in really-really secure mode, but still allow
1926 * the logging counters to be reset.
1927 */
1928 if (securelevel >= 3 && (sopt->sopt_name == IP_FW_ADD ||
1929 (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)))
1930 return (EPERM);
1931 error = 0;
1932
1933 switch (sopt->sopt_name) {
1934 case IP_FW_GET:
1935 /*
1936 * pass up a copy of the current rules. Static rules
1937 * come first (the last of which has number 65535),
1938 * followed by a possibly empty list of dynamic rule.
1939 * The last dynamic rule has NULL in the "next" field.
1940 */
1941 s = splimp();
1942 /* size of static rules */
1943 size = static_count * sizeof(struct ip_fw) ;
1944 if (ipfw_dyn_v) /* add size of dyn.rules */
1945 size += (dyn_count * sizeof(struct ipfw_dyn_rule));
1946
1947 /*
1948 * XXX todo: if the user passes a short length to know how
1949 * much room is needed, do not
1950 * bother filling up the buffer, just jump to the
1951 * sooptcopyout.
1952 */
1953 buf = malloc(size, M_TEMP, M_WAITOK);
1954 if (buf == 0) {
1955 splx(s);
1956 error = ENOBUFS;
1957 break;
1958 }
1959
1960 bp = buf ;
1961 LIST_FOREACH(fcp, &ip_fw_chain_head, next) {
1962 bcopy(fcp, bp, sizeof *fcp);
1963 bp++;
1964 }
1965 if (ipfw_dyn_v) {
1966 int i ;
1967 struct ipfw_dyn_rule *p, *dst, *last = NULL ;
1968
1969 dst = (struct ipfw_dyn_rule *)bp ;
1970 for (i = 0 ; i < curr_dyn_buckets ; i++ )
1971 for ( p = ipfw_dyn_v[i] ; p != NULL ; p = p->next, dst++ ) {
1972 bcopy(p, dst, sizeof *p);
1973 (int)dst->rule = p->rule->fw_number ;
1974 /*
1975 * store a non-null value in "next". The userland
1976 * code will interpret a NULL here as a marker
1977 * for the last dynamic rule.
1978 */
1979 dst->next = dst ;
1980 last = dst ;
1981 if (TIME_LEQ(dst->expire, time_second) )
1982 dst->expire = 0 ;
1983 else
1984 dst->expire -= time_second ;
1985 }
1986 if (last != NULL)
1987 last->next = NULL ; /* mark last dynamic rule */
1988 }
1989 splx(s);
1990
1991 error = sooptcopyout(sopt, buf, size);
1992 free(buf, M_TEMP);
1993 break;
1994
1995 case IP_FW_FLUSH:
1996 /*
1997 * Normally we cannot release the lock on each iteration.
1998 * We could do it here only because we start from the head all
1999 * the times so there is no risk of missing some entries.
2000 * On the other hand, the risk is that we end up with
2001 * a very inconsistent ruleset, so better keep the lock
2002 * around the whole cycle.
2003 *
2004 * XXX this code can be improved by resetting the head of
2005 * the list to point to the default rule, and then freeing
2006 * the old list without the need for a lock.
2007 */
2008
2009 s = splimp();
2010 while ( (fcp = LIST_FIRST(&ip_fw_chain_head)) &&
2011 fcp->fw_number != IPFW_DEFAULT_RULE )
2012 free_chain(fcp);
2013 splx(s);
2014 break;
2015
2016 case IP_FW_ADD:
2017 error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
2018 if (error || (error = check_ipfw_struct(&frwl)))
2019 break;
2020
2021 if (frwl.fw_number == IPFW_DEFAULT_RULE) {
2022 dprintf(("%s can't add rule %u\n", err_prefix,
2023 (unsigned)IPFW_DEFAULT_RULE));
2024 error = EINVAL;
2025 } else {
2026 error = add_entry(&ip_fw_chain_head, &frwl);
2027 if (!error && sopt->sopt_dir == SOPT_GET)
2028 error = sooptcopyout(sopt, &frwl, sizeof frwl);
2029 }
2030 break;
2031
2032 case IP_FW_DEL:
2033 error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
2034 if (error)
2035 break;
2036
2037 if (frwl.fw_number == IPFW_DEFAULT_RULE) {
2038 dprintf(("%s can't delete rule %u\n", err_prefix,
2039 (unsigned)IPFW_DEFAULT_RULE));
2040 error = EINVAL;
2041 } else {
2042 error = del_entry(&ip_fw_chain_head, frwl.fw_number);
2043 }
2044 break;
2045
2046 case IP_FW_ZERO:
2047 case IP_FW_RESETLOG:
2048 {
2049 int cmd = (sopt->sopt_name == IP_FW_RESETLOG );
2050 void *arg = NULL ;
2051
2052 if (sopt->sopt_val != 0) {
2053 error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
2054 if (error)
2055 break;
2056 arg = &frwl ;
2057 }
2058 error = zero_entry(arg, cmd);
2059 }
2060 break;
2061
2062 default:
2063 printf("ip_fw_ctl invalid option %d\n", sopt->sopt_name);
2064 error = EINVAL ;
2065 }
2066
2067 return (error);
2068}
2069
2070/**
2071 * dummynet needs a reference to the default rule, because rules can
2072 * be deleted while packets hold a reference to them (e.g. to resume
2073 * processing at the next rule). When this happens, dummynet changes
2074 * the reference to the default rule (probably it could well be a
2075 * NULL pointer, but this way we do not need to check for the special
2076 * case, plus here he have info on the default behaviour.
2077 */
2078struct ip_fw *ip_fw_default_rule ;
2079
2080void
2081ip_fw_init(void)
2082{
2083 struct ip_fw default_rule;
2084
2085 ip_fw_chk_ptr = ip_fw_chk;
2086 ip_fw_ctl_ptr = ip_fw_ctl;
2087 LIST_INIT(&ip_fw_chain_head);
2088
2089 bzero(&default_rule, sizeof default_rule);
2090 default_rule.fw_prot = IPPROTO_IP;
2091 default_rule.fw_number = IPFW_DEFAULT_RULE;
2092#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
2093 default_rule.fw_flg |= IP_FW_F_ACCEPT;
2094#else
2095 default_rule.fw_flg |= IP_FW_F_DENY;
2096#endif
2097 default_rule.fw_flg |= IP_FW_F_IN | IP_FW_F_OUT;
2098 if (check_ipfw_struct(&default_rule) != 0 ||
2099 add_entry(&ip_fw_chain_head, &default_rule))
2100 panic("ip_fw_init");
2101
2102 ip_fw_default_rule = LIST_FIRST(&ip_fw_chain_head) ;
2103 printf("IP packet filtering initialized, "
2104#ifdef IPDIVERT
2105 "divert enabled, "
2106#else
2107 "divert disabled, "
2108#endif
2109 "rule-based forwarding enabled, "
2110#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
2111 "default to accept, ");
2112#else
2113 "default to deny, " );
2114#endif
2115#ifndef IPFIREWALL_VERBOSE
2116 printf("logging disabled\n");
2117#else
2118 if (fw_verbose_limit == 0)
2119 printf("unlimited logging\n");
2120 else
2121 printf("logging limited to %d packets/entry by default\n",
2122 fw_verbose_limit);
2123#endif
2124}
2125
2126static int
2127ipfw_modevent(module_t mod, int type, void *unused)
2128{
2129 int s;
2130 int err = 0 ;
2131#if defined(KLD_MODULE)
2132 struct ip_fw *fcp;
2133#endif
2134
2135 switch (type) {
2136 case MOD_LOAD:
2137 s = splimp();
2138 if (IPFW_LOADED) {
2139 splx(s);
2140 printf("IP firewall already loaded\n");
2141 err = EEXIST ;
2142 } else {
2143 ip_fw_init();
2144 splx(s);
2145 }
2146 break ;
2147 case MOD_UNLOAD:
2148#if !defined(KLD_MODULE)
2149 printf("ipfw statically compiled, cannot unload\n");
2150 err = EBUSY;
2151#else
2152 s = splimp();
2153 ip_fw_chk_ptr = NULL ;
2154 ip_fw_ctl_ptr = NULL ;
2155 while ( (fcp = LIST_FIRST(&ip_fw_chain_head)) != NULL)
2156 free_chain(fcp);
2157 splx(s);
2158 printf("IP firewall unloaded\n");
2159#endif
2160 break ;
2161
2162 default:
2163 break;
2164 }
2165 return err;
2166}
2167
2168static moduledata_t ipfwmod = {
2169 "ipfw",
2170 ipfw_modevent,
2171 0
2172};
2173DECLARE_MODULE(ipfw, ipfwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);
2174#endif /* !IPFW2 */