xref: /freebsd/sbin/ipfw/main.c (revision 586f63035fbe5e45cfc971037fd76375661ece26)
1 /*
2  * Copyright (c) 2002-2003,2010 Luigi Rizzo
3  * Copyright (c) 1996 Alex Nash, Paul Traina, Poul-Henning Kamp
4  * Copyright (c) 1994 Ugen J.S.Antsilevich
5  *
6  * Idea and grammar partially left from:
7  * Copyright (c) 1993 Daniel Boulet
8  *
9  * Redistribution and use in source forms, with and without modification,
10  * are permitted provided that this entire comment appears intact.
11  *
12  * Redistribution in binary form may occur without any restrictions.
13  * Obviously, it would be nice if you gave credit where credit is due
14  * but requiring it would be too onerous.
15  *
16  * This software is provided ``AS IS'' without any warranties of any kind.
17  *
18  * Command line interface for IP firewall facility
19  *
20  * $FreeBSD$
21  */
22 
23 #include <sys/wait.h>
24 #include <ctype.h>
25 #include <err.h>
26 #include <errno.h>
27 #include <signal.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <sysexits.h>
32 #include <unistd.h>
33 
34 #include "ipfw2.h"
35 
36 static void
37 help(void)
38 {
39 	fprintf(stderr,
40 "ipfw syntax summary (but please do read the ipfw(8) manpage):\n\n"
41 "\tipfw [-abcdefhnNqStTv] <command>\n\n"
42 "where <command> is one of the following:\n\n"
43 "add [num] [set N] [prob x] RULE-BODY\n"
44 "{pipe|queue} N config PIPE-BODY\n"
45 "[pipe|queue] {zero|delete|show} [N{,N}]\n"
46 "nat N config {ip IPADDR|if IFNAME|log|deny_in|same_ports|unreg_only|reset|\n"
47 "		reverse|proxy_only|redirect_addr linkspec|\n"
48 "		redirect_port linkspec|redirect_proto linkspec}\n"
49 "set [disable N... enable N...] | move [rule] X to Y | swap X Y | show\n"
50 "set N {show|list|zero|resetlog|delete} [N{,N}] | flush\n"
51 "table N {add ip[/bits] [value] | delete ip[/bits] | flush | list}\n"
52 "table all {flush | list}\n"
53 "\n"
54 "RULE-BODY:	check-state [PARAMS] | ACTION [PARAMS] ADDR [OPTION_LIST]\n"
55 "ACTION:	check-state | allow | count | deny | unreach{,6} CODE |\n"
56 "               skipto N | {divert|tee} PORT | forward ADDR |\n"
57 "               pipe N | queue N | nat N | setfib FIB | reass\n"
58 "PARAMS: 	[log [logamount LOGLIMIT]] [altq QUEUE_NAME]\n"
59 "ADDR:		[ MAC dst src ether_type ] \n"
60 "		[ ip from IPADDR [ PORT ] to IPADDR [ PORTLIST ] ]\n"
61 "		[ ipv6|ip6 from IP6ADDR [ PORT ] to IP6ADDR [ PORTLIST ] ]\n"
62 "IPADDR:	[not] { any | me | ip/bits{x,y,z} | table(t[,v]) | IPLIST }\n"
63 "IP6ADDR:	[not] { any | me | me6 | ip6/bits | IP6LIST }\n"
64 "IP6LIST:	{ ip6 | ip6/bits }[,IP6LIST]\n"
65 "IPLIST:	{ ip | ip/bits | ip:mask }[,IPLIST]\n"
66 "OPTION_LIST:	OPTION [OPTION_LIST]\n"
67 "OPTION:	bridged | diverted | diverted-loopback | diverted-output |\n"
68 "	{dst-ip|src-ip} IPADDR | {dst-ip6|src-ip6|dst-ipv6|src-ipv6} IP6ADDR |\n"
69 "	{dst-port|src-port} LIST |\n"
70 "	estab | frag | {gid|uid} N | icmptypes LIST | in | out | ipid LIST |\n"
71 "	iplen LIST | ipoptions SPEC | ipprecedence | ipsec | iptos SPEC |\n"
72 "	ipttl LIST | ipversion VER | keep-state | layer2 | limit ... |\n"
73 "	icmp6types LIST | ext6hdr LIST | flow-id N[,N] | fib FIB |\n"
74 "	mac ... | mac-type LIST | proto LIST | {recv|xmit|via} {IF|IPADDR} |\n"
75 "	setup | {tcpack|tcpseq|tcpwin} NN | tcpflags SPEC | tcpoptions SPEC |\n"
76 "	tcpdatalen LIST | verrevpath | versrcreach | antispoof\n"
77 );
78 
79 	exit(0);
80 }
81 
82 /*
83  * Called with the arguments, including program name because getopt
84  * wants it to be present.
85  * Returns 0 if successful, 1 if empty command, errx() in case of errors.
86  * First thing we do is process parameters creating an argv[] array
87  * which includes the program name and a NULL entry at the end.
88  * If we are called with a single string, we split it on whitespace.
89  * Also, arguments with a trailing ',' are joined to the next one.
90  * The pointers (av[]) and data are in a single chunk of memory.
91  * av[0] points to the original program name, all other entries
92  * point into the allocated chunk.
93  */
94 static int
95 ipfw_main(int oldac, char **oldav)
96 {
97 	int ch, ac;
98 	const char *errstr;
99 	char **av, **save_av;
100 	int do_acct = 0;		/* Show packet/byte count */
101 	int try_next = 0;		/* set if pipe cmd not found */
102 	int av_size;			/* compute the av size */
103 	char *av_p;			/* used to build the av list */
104 
105 #define WHITESP		" \t\f\v\n\r"
106 	if (oldac < 2)
107 		return 1;	/* need at least one argument */
108 
109 	if (oldac == 2) {
110 		/*
111 		 * If we are called with one argument, try to split it into
112 		 * words for subsequent parsing. Spaces after a ',' are
113 		 * removed by copying the string in-place.
114 		 */
115 		char *arg = oldav[1];	/* The string is the first arg. */
116 		int l = strlen(arg);
117 		int copy = 0;		/* 1 if we need to copy, 0 otherwise */
118 		int i, j;
119 
120 		for (i = j = 0; i < l; i++) {
121 			if (arg[i] == '#')	/* comment marker */
122 				break;
123 			if (copy) {
124 				arg[j++] = arg[i];
125 				copy = !index("," WHITESP, arg[i]);
126 			} else {
127 				copy = !index(WHITESP, arg[i]);
128 				if (copy)
129 					arg[j++] = arg[i];
130 			}
131 		}
132 		if (!copy && j > 0)	/* last char was a 'blank', remove it */
133 			j--;
134 		l = j;			/* the new argument length */
135 		arg[j++] = '\0';
136 		if (l == 0)		/* empty string! */
137 			return 1;
138 
139 		/*
140 		 * First, count number of arguments. Because of the previous
141 		 * processing, this is just the number of blanks plus 1.
142 		 */
143 		for (i = 0, ac = 1; i < l; i++)
144 			if (index(WHITESP, arg[i]) != NULL)
145 				ac++;
146 
147 		/*
148 		 * Allocate the argument list structure as a single block
149 		 * of memory, containing pointers and the argument
150 		 * strings. We include one entry for the program name
151 		 * because getopt expects it, and a NULL at the end
152 		 * to simplify further parsing.
153 		 */
154 		ac++;		/* add 1 for the program name */
155 		av_size = (ac+1) * sizeof(char *) + l + 1;
156 		av = safe_calloc(av_size, 1);
157 
158 		/*
159 		 * Init the argument pointer to the end of the array
160 		 * and copy arguments from arg[] to av[]. For each one,
161 		 * j is the initial character, i is the one past the end.
162 		 */
163 		av_p = (char *)&av[ac+1];
164 		for (ac = 1, i = j = 0; i < l; i++) {
165 			if (index(WHITESP, arg[i]) != NULL || i == l-1) {
166 				if (i == l-1)
167 					i++;
168 				bcopy(arg+j, av_p, i-j);
169 				av[ac] = av_p;
170 				av_p += i-j;	/* the lenght of the string */
171 				*av_p++ = '\0';
172 				ac++;
173 				j = i + 1;
174 			}
175 		}
176 	} else {
177 		/*
178 		 * If an argument ends with ',' join with the next one.
179 		 */
180 		int first, i, l=0;
181 
182 		/*
183 		 * Allocate the argument list structure as a single block
184 		 * of memory, containing both pointers and the argument
185 		 * strings. We include some space for the program name
186 		 * because getopt expects it.
187 		 * We add an extra pointer to the end of the array,
188 		 * to make simpler further parsing.
189 		 */
190 		for (i=0; i<oldac; i++)
191 			l += strlen(oldav[i]);
192 
193 		av_size = (oldac+1) * sizeof(char *) + l + oldac;
194 		av = safe_calloc(av_size, 1);
195 
196 		/*
197 		 * Init the argument pointer to the end of the array
198 		 * and copy arguments from arg[] to av[]
199 		 */
200 		av_p = (char *)&av[oldac+1];
201 		for (first = i = ac = 1, l = 0; i < oldac; i++) {
202 			char *arg = oldav[i];
203 			int k = strlen(arg);
204 
205 			l += k;
206 			if (arg[k-1] != ',' || i == oldac-1) {
207 				/* Time to copy. */
208 				av[ac] = av_p;
209 				for (l=0; first <= i; first++) {
210 					strcat(av_p, oldav[first]);
211 					av_p += strlen(oldav[first]);
212 				}
213 				*av_p++ = '\0';
214 				ac++;
215 				l = 0;
216 				first = i+1;
217 			}
218 		}
219 	}
220 
221 	/*
222 	 * set the progname pointer to the original string
223 	 * and terminate the array with null
224 	 */
225 	av[0] = oldav[0];
226 	av[ac] = NULL;
227 
228 	/* Set the force flag for non-interactive processes */
229 	if (!co.do_force)
230 		co.do_force = !isatty(STDIN_FILENO);
231 
232 #ifdef EMULATE_SYSCTL /* sysctl emulation */
233 	if ( ac >= 2 && !strcmp(av[1], "sysctl")) {
234 		char *s;
235 		int i;
236 
237 		if (ac != 3) {
238 			printf(	"sysctl emulation usage:\n"
239 				"	ipfw sysctl name[=value]\n"
240 				"	ipfw sysctl -a\n");
241 			return 0;
242 		}
243 		s = index(av[2], '=');
244 		if (s == NULL) {
245 			s = !strcmp(av[2], "-a") ? NULL : av[2];
246 			sysctlbyname(s, NULL, NULL, NULL, 0);
247 		} else {	/* ipfw sysctl x.y.z=value */
248 			/* assume an INT value, will extend later */
249 			if (s[1] == '\0') {
250 				printf("ipfw sysctl: missing value\n\n");
251 				return 0;
252 			}
253 			*s = '\0';
254 			i = strtol(s+1, NULL, 0);
255 			sysctlbyname(av[2], NULL, NULL, &i, sizeof(int));
256 		}
257 		return 0;
258 	}
259 #endif
260 
261 	/* Save arguments for final freeing of memory. */
262 	save_av = av;
263 
264 	optind = optreset = 1;	/* restart getopt() */
265 	while ((ch = getopt(ac, av, "abcdefhinNp:qs:STtv")) != -1)
266 		switch (ch) {
267 		case 'a':
268 			do_acct = 1;
269 			break;
270 
271 		case 'b':
272 			co.comment_only = 1;
273 			co.do_compact = 1;
274 			break;
275 
276 		case 'c':
277 			co.do_compact = 1;
278 			break;
279 
280 		case 'd':
281 			co.do_dynamic = 1;
282 			break;
283 
284 		case 'e':
285 			co.do_expired = 1;
286 			break;
287 
288 		case 'f':
289 			co.do_force = 1;
290 			break;
291 
292 		case 'h': /* help */
293 			free(save_av);
294 			help();
295 			break;	/* NOTREACHED */
296 
297 		case 'i':
298 			co.do_value_as_ip = 1;
299 			break;
300 
301 		case 'n':
302 			co.test_only = 1;
303 			break;
304 
305 		case 'N':
306 			co.do_resolv = 1;
307 			break;
308 
309 		case 'p':
310 			errx(EX_USAGE, "An absolute pathname must be used "
311 			    "with -p option.");
312 
313 		case 'q':
314 			co.do_quiet = 1;
315 			break;
316 
317 		case 's': /* sort */
318 			co.do_sort = atoi(optarg);
319 			break;
320 
321 		case 'S':
322 			co.show_sets = 1;
323 			break;
324 
325 		case 't':
326 			co.do_time = 1;
327 			break;
328 
329 		case 'T':
330 			co.do_time = 2;	/* numeric timestamp */
331 			break;
332 
333 		case 'v': /* verbose */
334 			co.verbose = 1;
335 			break;
336 
337 		default:
338 			free(save_av);
339 			return 1;
340 		}
341 
342 	ac -= optind;
343 	av += optind;
344 	NEED1("bad arguments, for usage summary ``ipfw''");
345 
346 	/*
347 	 * An undocumented behaviour of ipfw1 was to allow rule numbers first,
348 	 * e.g. "100 add allow ..." instead of "add 100 allow ...".
349 	 * In case, swap first and second argument to get the normal form.
350 	 */
351 	if (ac > 1 && isdigit(*av[0])) {
352 		char *p = av[0];
353 
354 		av[0] = av[1];
355 		av[1] = p;
356 	}
357 
358 	/*
359 	 * Optional: pipe, queue or nat.
360 	 */
361 	co.do_nat = 0;
362 	co.do_pipe = 0;
363 	co.use_set = 0;
364 	if (!strncmp(*av, "nat", strlen(*av)))
365  		co.do_nat = 1;
366  	else if (!strncmp(*av, "pipe", strlen(*av)))
367 		co.do_pipe = 1;
368 	else if (_substrcmp(*av, "queue") == 0)
369 		co.do_pipe = 2;
370 	else if (_substrcmp(*av, "flowset") == 0)
371 		co.do_pipe = 2;
372 	else if (_substrcmp(*av, "sched") == 0)
373 		co.do_pipe = 3;
374 	else if (!strncmp(*av, "set", strlen(*av))) {
375 		if (ac > 1 && isdigit(av[1][0])) {
376 			co.use_set = strtonum(av[1], 0, resvd_set_number,
377 					&errstr);
378 			if (errstr)
379 				errx(EX_DATAERR,
380 				    "invalid set number %s\n", av[1]);
381 			ac -= 2; av += 2; co.use_set++;
382 		}
383 	}
384 
385 	if (co.do_pipe || co.do_nat) {
386 		ac--;
387 		av++;
388 	}
389 	NEED1("missing command");
390 
391 	/*
392 	 * For pipes, queues and nats we normally say 'nat|pipe NN config'
393 	 * but the code is easier to parse as 'nat|pipe config NN'
394 	 * so we swap the two arguments.
395 	 */
396 	if ((co.do_pipe || co.do_nat) && ac > 1 && isdigit(*av[0])) {
397 		char *p = av[0];
398 
399 		av[0] = av[1];
400 		av[1] = p;
401 	}
402 
403 	if (co.use_set == 0) {
404 		if (_substrcmp(*av, "add") == 0)
405 			ipfw_add(av);
406 		else if (co.do_nat && _substrcmp(*av, "show") == 0)
407  			ipfw_show_nat(ac, av);
408 		else if (co.do_pipe && _substrcmp(*av, "config") == 0)
409 			ipfw_config_pipe(ac, av);
410 		else if (co.do_nat && _substrcmp(*av, "config") == 0)
411  			ipfw_config_nat(ac, av);
412 		else if (_substrcmp(*av, "set") == 0)
413 			ipfw_sets_handler(av);
414 		else if (_substrcmp(*av, "table") == 0)
415 			ipfw_table_handler(ac, av);
416 		else if (_substrcmp(*av, "enable") == 0)
417 			ipfw_sysctl_handler(av, 1);
418 		else if (_substrcmp(*av, "disable") == 0)
419 			ipfw_sysctl_handler(av, 0);
420 		else
421 			try_next = 1;
422 	}
423 
424 	if (co.use_set || try_next) {
425 		if (_substrcmp(*av, "delete") == 0)
426 			ipfw_delete(av);
427 		else if (_substrcmp(*av, "flush") == 0)
428 			ipfw_flush(co.do_force);
429 		else if (_substrcmp(*av, "zero") == 0)
430 			ipfw_zero(ac, av, 0 /* IP_FW_ZERO */);
431 		else if (_substrcmp(*av, "resetlog") == 0)
432 			ipfw_zero(ac, av, 1 /* IP_FW_RESETLOG */);
433 		else if (_substrcmp(*av, "print") == 0 ||
434 			 _substrcmp(*av, "list") == 0)
435 			ipfw_list(ac, av, do_acct);
436 		else if (_substrcmp(*av, "show") == 0)
437 			ipfw_list(ac, av, 1 /* show counters */);
438 		else
439 			errx(EX_USAGE, "bad command `%s'", *av);
440 	}
441 
442 	/* Free memory allocated in the argument parsing. */
443 	free(save_av);
444 	return 0;
445 }
446 
447 
448 static void
449 ipfw_readfile(int ac, char *av[])
450 {
451 #define MAX_ARGS	32
452 	char buf[4096];
453 	char *progname = av[0];		/* original program name */
454 	const char *cmd = NULL;		/* preprocessor name, if any */
455 	const char *filename = av[ac-1]; /* file to read */
456 	int	c, lineno=0;
457 	FILE	*f = NULL;
458 	pid_t	preproc = 0;
459 
460 	while ((c = getopt(ac, av, "cfNnp:qS")) != -1) {
461 		switch(c) {
462 		case 'c':
463 			co.do_compact = 1;
464 			break;
465 
466 		case 'f':
467 			co.do_force = 1;
468 			break;
469 
470 		case 'N':
471 			co.do_resolv = 1;
472 			break;
473 
474 		case 'n':
475 			co.test_only = 1;
476 			break;
477 
478 		case 'p':
479 			/*
480 			 * ipfw -p cmd [args] filename
481 			 *
482 			 * We are done with getopt(). All arguments
483 			 * except the filename go to the preprocessor,
484 			 * so we need to do the following:
485 			 * - check that a filename is actually present;
486 			 * - advance av by optind-1 to skip arguments
487 			 *   already processed;
488 			 * - decrease ac by optind, to remove the args
489 			 *   already processed and the final filename;
490 			 * - set the last entry in av[] to NULL so
491 			 *   popen() can detect the end of the array;
492 			 * - set optind=ac to let getopt() terminate.
493 			 */
494 			if (optind == ac)
495 				errx(EX_USAGE, "no filename argument");
496 			cmd = optarg;
497 			av[ac-1] = NULL;
498 			av += optind - 1;
499 			ac -= optind;
500 			optind = ac;
501 			break;
502 
503 		case 'q':
504 			co.do_quiet = 1;
505 			break;
506 
507 		case 'S':
508 			co.show_sets = 1;
509 			break;
510 
511 		default:
512 			errx(EX_USAGE, "bad arguments, for usage"
513 			     " summary ``ipfw''");
514 		}
515 
516 	}
517 
518 	if (cmd == NULL && ac != optind + 1)
519 		errx(EX_USAGE, "extraneous filename arguments %s", av[ac-1]);
520 
521 	if ((f = fopen(filename, "r")) == NULL)
522 		err(EX_UNAVAILABLE, "fopen: %s", filename);
523 
524 	if (cmd != NULL) {			/* pipe through preprocessor */
525 		int pipedes[2];
526 
527 		if (pipe(pipedes) == -1)
528 			err(EX_OSERR, "cannot create pipe");
529 
530 		preproc = fork();
531 		if (preproc == -1)
532 			err(EX_OSERR, "cannot fork");
533 
534 		if (preproc == 0) {
535 			/*
536 			 * Child, will run the preprocessor with the
537 			 * file on stdin and the pipe on stdout.
538 			 */
539 			if (dup2(fileno(f), 0) == -1
540 			    || dup2(pipedes[1], 1) == -1)
541 				err(EX_OSERR, "dup2()");
542 			fclose(f);
543 			close(pipedes[1]);
544 			close(pipedes[0]);
545 			execvp(cmd, av);
546 			err(EX_OSERR, "execvp(%s) failed", cmd);
547 		} else { /* parent, will reopen f as the pipe */
548 			fclose(f);
549 			close(pipedes[1]);
550 			if ((f = fdopen(pipedes[0], "r")) == NULL) {
551 				int savederrno = errno;
552 
553 				(void)kill(preproc, SIGTERM);
554 				errno = savederrno;
555 				err(EX_OSERR, "fdopen()");
556 			}
557 		}
558 	}
559 
560 	while (fgets(buf, sizeof(buf), f)) {		/* read commands */
561 		char linename[20];
562 		char *args[2];
563 
564 		lineno++;
565 		snprintf(linename, sizeof(linename), "Line %d", lineno);
566 		setprogname(linename); /* XXX */
567 		args[0] = progname;
568 		args[1] = buf;
569 		ipfw_main(2, args);
570 	}
571 	fclose(f);
572 	if (cmd != NULL) {
573 		int status;
574 
575 		if (waitpid(preproc, &status, 0) == -1)
576 			errx(EX_OSERR, "waitpid()");
577 		if (WIFEXITED(status) && WEXITSTATUS(status) != EX_OK)
578 			errx(EX_UNAVAILABLE,
579 			    "preprocessor exited with status %d",
580 			    WEXITSTATUS(status));
581 		else if (WIFSIGNALED(status))
582 			errx(EX_UNAVAILABLE,
583 			    "preprocessor exited with signal %d",
584 			    WTERMSIG(status));
585 	}
586 }
587 
588 int
589 main(int ac, char *av[])
590 {
591 #if defined(_WIN32) && defined(TCC)
592 	{
593 		WSADATA wsaData;
594 		int ret=0;
595 		unsigned short wVersionRequested = MAKEWORD(2, 2);
596 		ret = WSAStartup(wVersionRequested, &wsaData);
597 		if (ret != 0) {
598 			/* Tell the user that we could not find a usable */
599 			/* Winsock DLL.				  */
600 			printf("WSAStartup failed with error: %d\n", ret);
601 			return 1;
602 		}
603 	}
604 #endif
605 	/*
606 	 * If the last argument is an absolute pathname, interpret it
607 	 * as a file to be preprocessed.
608 	 */
609 
610 	if (ac > 1 && av[ac - 1][0] == '/') {
611 		if (access(av[ac - 1], R_OK) == 0)
612 			ipfw_readfile(ac, av);
613 		else
614 			err(EX_USAGE, "pathname: %s", av[ac - 1]);
615 	} else {
616 		if (ipfw_main(ac, av)) {
617 			errx(EX_USAGE,
618 			    "usage: ipfw [options]\n"
619 			    "do \"ipfw -h\" or \"man ipfw\" for details");
620 		}
621 	}
622 	return EX_OK;
623 }
624