m_ipt.c revision ece02ea0a388a0bda5e5dff425fe93e50b2d5c9b 
1/*
2 * m_ipt.c	iptables based targets
3 * 		utilities mostly ripped from iptables <duh, its the linux way>
4 *
5 *		This program is free software; you can distribute it and/or
6 *		modify it under the terms of the GNU General Public License
7 *		as published by the Free Software Foundation; either version
8 *		2 of the License, or (at your option) any later version.
9 *
10 * Authors:  J Hadi Salim (hadi@cyberus.ca)
11 */
12
13#include <syslog.h>
14#include <sys/socket.h>
15#include <netinet/in.h>
16#include <arpa/inet.h>
17#include <linux/if.h>
18#include <iptables.h>
19#include <linux/netfilter.h>
20#include <linux/netfilter_ipv4/ip_tables.h>
21#include "utils.h"
22#include "tc_util.h"
23#include <linux/tc_act/tc_ipt.h>
24#include <stdio.h>
25#include <dlfcn.h>
26#include <getopt.h>
27#include <errno.h>
28#include <string.h>
29#include <netdb.h>
30#include <stdlib.h>
31#include <ctype.h>
32#include <stdarg.h>
33#include <limits.h>
34#include <unistd.h>
35#include <fcntl.h>
36#include <sys/wait.h>
37
38static const char *pname = "tc-ipt";
39static const char *tname = "mangle";
40static const char *pversion = "0.1";
41
42static const char *ipthooks[] = {
43	"NF_IP_PRE_ROUTING",
44	"NF_IP_LOCAL_IN",
45	"NF_IP_FORWARD",
46	"NF_IP_LOCAL_OUT",
47	"NF_IP_POST_ROUTING",
48};
49
50static struct option original_opts[] = {
51	{"jump", 1, 0, 'j'},
52	{0, 0, 0, 0}
53};
54
55static struct iptables_target *t_list = NULL;
56static struct option *opts = original_opts;
57static unsigned int global_option_offset = 0;
58#define OPTION_OFFSET 256
59
60char *lib_dir;
61
62void
63register_target(struct iptables_target *me)
64{
65/*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
66*/
67	me->next = t_list;
68	t_list = me;
69
70}
71
72void
73exit_tryhelp(int status)
74{
75	fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
76		pname, pname);
77	exit(status);
78}
79
80void
81exit_error(enum exittype status, char *msg, ...)
82{
83	va_list args;
84
85	va_start(args, msg);
86	fprintf(stderr, "%s v%s: ", pname, pversion);
87	vfprintf(stderr, msg, args);
88	va_end(args);
89	fprintf(stderr, "\n");
90	if (status == PARAMETER_PROBLEM)
91		exit_tryhelp(status);
92	if (status == VERSION_PROBLEM)
93		fprintf(stderr,
94			"Perhaps iptables or your kernel needs to be upgraded.\n");
95	exit(status);
96}
97
98/* stolen from iptables 1.2.11
99They should really have them as a library so i can link to them
100Email them next time i remember
101*/
102
103char *
104addr_to_dotted(const struct in_addr *addrp)
105{
106	static char buf[20];
107	const unsigned char *bytep;
108
109	bytep = (const unsigned char *) &(addrp->s_addr);
110	sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
111	return buf;
112}
113
114int string_to_number_ll(const char *s, unsigned long long min,
115			unsigned long long max,
116		 unsigned long long *ret)
117{
118	unsigned long long number;
119	char *end;
120
121	/* Handle hex, octal, etc. */
122	errno = 0;
123	number = strtoull(s, &end, 0);
124	if (*end == '\0' && end != s) {
125		/* we parsed a number, let's see if we want this */
126		if (errno != ERANGE && min <= number && (!max || number <= max)) {
127			*ret = number;
128			return 0;
129		}
130	}
131	return -1;
132}
133
134int string_to_number_l(const char *s, unsigned long min, unsigned long max,
135		       unsigned long *ret)
136{
137	int result;
138	unsigned long long number;
139
140	result = string_to_number_ll(s, min, max, &number);
141	*ret = (unsigned long)number;
142
143	return result;
144}
145
146int string_to_number(const char *s, unsigned int min, unsigned int max,
147		unsigned int *ret)
148{
149	int result;
150	unsigned long number;
151
152	result = string_to_number_l(s, min, max, &number);
153	*ret = (unsigned int)number;
154
155	return result;
156}
157
158static void free_opts(struct option *opts)
159{
160	if (opts != original_opts) {
161		free(opts);
162		opts = original_opts;
163		global_option_offset = 0;
164	}
165}
166
167static struct option *
168merge_options(struct option *oldopts, const struct option *newopts,
169	      unsigned int *option_offset)
170{
171	struct option *merge;
172	unsigned int num_old, num_new, i;
173
174	for (num_old = 0; oldopts[num_old].name; num_old++) ;
175	for (num_new = 0; newopts[num_new].name; num_new++) ;
176
177	*option_offset = global_option_offset + OPTION_OFFSET;
178
179	merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
180	memcpy(merge, oldopts, num_old * sizeof (struct option));
181	for (i = 0; i < num_new; i++) {
182		merge[num_old + i] = newopts[i];
183		merge[num_old + i].val += *option_offset;
184	}
185	memset(merge + num_old + num_new, 0, sizeof (struct option));
186
187	return merge;
188}
189
190static void *
191fw_calloc(size_t count, size_t size)
192{
193	void *p;
194
195	if ((p = (void *) calloc(count, size)) == NULL) {
196		perror("iptables: calloc failed");
197		exit(1);
198	}
199	return p;
200}
201
202static struct iptables_target *
203find_t(char *name)
204{
205	struct iptables_target *m;
206	for (m = t_list; m; m = m->next) {
207		if (strcmp(m->name, name) == 0)
208			return m;
209	}
210
211	return NULL;
212}
213
214static struct iptables_target *
215get_target_name(const char *name)
216{
217	void *handle;
218	char *error;
219	char *new_name, *lname;
220	struct iptables_target *m;
221	char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
222
223	new_name = malloc(strlen(name) + 1);
224	lname = malloc(strlen(name) + 1);
225	if (new_name)
226		memset(new_name, '\0', strlen(name) + 1);
227	else
228		exit_error(PARAMETER_PROBLEM, "get_target_name");
229
230	if (lname)
231		memset(lname, '\0', strlen(name) + 1);
232	else
233		exit_error(PARAMETER_PROBLEM, "get_target_name");
234
235	strcpy(new_name, name);
236	strcpy(lname, name);
237
238	if (isupper(lname[0])) {
239		int i;
240		for (i = 0; i < strlen(name); i++) {
241			lname[i] = tolower(lname[i]);
242		}
243	}
244
245	if (islower(new_name[0])) {
246		int i;
247		for (i = 0; i < strlen(new_name); i++) {
248			new_name[i] = toupper(new_name[i]);
249		}
250	}
251
252	sprintf(path,  "%s/libipt_%s.so",lib_dir, new_name);
253	handle = dlopen(path, RTLD_LAZY);
254	if (!handle) {
255		sprintf(path, lib_dir, "/libipt_%s.so", lname);
256		handle = dlopen(path, RTLD_LAZY);
257		if (!handle) {
258			fputs(dlerror(), stderr);
259			printf("\n");
260			return NULL;
261		}
262	}
263
264	m = dlsym(handle, new_name);
265	if ((error = dlerror()) != NULL) {
266		m = (struct iptables_target *) dlsym(handle, lname);
267		if ((error = dlerror()) != NULL) {
268			m = find_t(new_name);
269			if (NULL == m) {
270				m = find_t(lname);
271				if (NULL == m) {
272					fputs(error, stderr);
273					fprintf(stderr, "\n");
274					dlclose(handle);
275					return NULL;
276				}
277			}
278		}
279	}
280
281	return m;
282}
283
284
285struct in_addr *dotted_to_addr(const char *dotted)
286{
287	static struct in_addr addr;
288	unsigned char *addrp;
289	char *p, *q;
290	unsigned int onebyte;
291	int i;
292	char buf[20];
293
294	/* copy dotted string, because we need to modify it */
295	strncpy(buf, dotted, sizeof (buf) - 1);
296	addrp = (unsigned char *) &(addr.s_addr);
297
298	p = buf;
299	for (i = 0; i < 3; i++) {
300		if ((q = strchr(p, '.')) == NULL)
301			return (struct in_addr *) NULL;
302
303		*q = '\0';
304		if (string_to_number(p, 0, 255, &onebyte) == -1)
305			return (struct in_addr *) NULL;
306
307		addrp[i] = (unsigned char) onebyte;
308		p = q + 1;
309	}
310
311	/* we've checked 3 bytes, now we check the last one */
312	if (string_to_number(p, 0, 255, &onebyte) == -1)
313		return (struct in_addr *) NULL;
314
315	addrp[3] = (unsigned char) onebyte;
316
317	return &addr;
318}
319
320static void set_revision(char *name, u_int8_t revision)
321{
322	/* Old kernel sources don't have ".revision" field,
323	*  but we stole a byte from name. */
324	name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
325	name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
326}
327
328/*
329 * we may need to check for version mismatch
330*/
331int
332build_st(struct iptables_target *target, struct ipt_entry_target *t)
333{
334	unsigned int nfcache = 0;
335
336	if (target) {
337		size_t size;
338
339		size =
340		    IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
341
342		if (NULL == t) {
343			target->t = fw_calloc(1, size);
344			target->t->u.target_size = size;
345
346			if (target->init != NULL)
347				target->init(target->t, &nfcache);
348			set_revision(target->t->u.user.name, target->revision);
349		} else {
350			target->t = t;
351		}
352		strcpy(target->t->u.user.name, target->name);
353		return 0;
354	}
355
356	return -1;
357}
358
359static int parse_ipt(struct action_util *a,int *argc_p,
360		     char ***argv_p, int tca_id, struct nlmsghdr *n)
361{
362	struct iptables_target *m = NULL;
363	struct ipt_entry fw;
364	struct rtattr *tail;
365	int c;
366	int rargc = *argc_p;
367	char **argv = *argv_p;
368	int argc = 0, iargc = 0;
369	char k[16];
370	int res = -1;
371	int size = 0;
372	int iok = 0, ok = 0;
373	__u32 hook = 0, index = 0;
374	res = 0;
375
376	lib_dir = getenv("IPTABLES_LIB_DIR");
377	if (!lib_dir)
378		lib_dir = IPT_LIB_DIR;
379
380	{
381		int i;
382		for (i = 0; i < rargc; i++) {
383			if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
384				break;
385			}
386		}
387		iargc = argc = i;
388	}
389
390	if (argc <= 2) {
391		fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
392		return -1;
393	}
394
395	while (1) {
396		c = getopt_long(argc, argv, "j:", opts, NULL);
397		if (c == -1)
398			break;
399		switch (c) {
400		case 'j':
401			m = get_target_name(optarg);
402			if (NULL != m) {
403
404				if (0 > build_st(m, NULL)) {
405					printf(" %s error \n", m->name);
406					return -1;
407				}
408				opts =
409				    merge_options(opts, m->extra_opts,
410						  &m->option_offset);
411			} else {
412				fprintf(stderr," failed to find target %s\n\n", optarg);
413				return -1;
414			}
415			ok++;
416			break;
417
418		default:
419			memset(&fw, 0, sizeof (fw));
420			if (m) {
421				m->parse(c - m->option_offset, argv, 0,
422					 &m->tflags, NULL, &m->t);
423			} else {
424				fprintf(stderr," failed to find target %s\n\n", optarg);
425				return -1;
426
427			}
428			ok++;
429			break;
430
431		}
432	}
433
434	if (iargc > optind) {
435		if (matches(argv[optind], "index") == 0) {
436			if (get_u32(&index, argv[optind + 1], 10)) {
437				fprintf(stderr, "Illegal \"index\"\n");
438				free_opts(opts);
439				return -1;
440			}
441			iok++;
442
443			optind += 2;
444		}
445	}
446
447	if (!ok && !iok) {
448		fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
449		return -1;
450	}
451
452	/* check that we passed the correct parameters to the target */
453	if (m)
454		m->final_check(m->tflags);
455
456	{
457		struct tcmsg *t = NLMSG_DATA(n);
458		if (t->tcm_parent != TC_H_ROOT
459		    && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
460			hook = NF_IP_PRE_ROUTING;
461		} else {
462			hook = NF_IP_POST_ROUTING;
463		}
464	}
465
466	tail = NLMSG_TAIL(n);
467	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
468	fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
469	fprintf(stdout, "\ttarget: ");
470
471	if (m)
472		m->print(NULL, m->t, 0);
473	fprintf(stdout, " index %d\n", index);
474
475	if (strlen(tname) > 16) {
476		size = 16;
477		k[15] = 0;
478	} else {
479		size = 1 + strlen(tname);
480	}
481	strncpy(k, tname, size);
482
483	addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
484	addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
485	addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
486	if (m)
487		addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
488	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
489
490	argc -= optind;
491	argv += optind;
492	*argc_p = rargc - iargc;
493	*argv_p = argv;
494
495	optind = 1;
496	free_opts(opts);
497
498	return 0;
499
500}
501
502static int
503print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
504{
505	struct rtattr *tb[TCA_IPT_MAX + 1];
506	struct ipt_entry_target *t = NULL;
507
508	if (arg == NULL)
509		return -1;
510
511	lib_dir = getenv("IPTABLES_LIB_DIR");
512	if (!lib_dir)
513		lib_dir = IPT_LIB_DIR;
514
515	parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
516
517	if (tb[TCA_IPT_TABLE] == NULL) {
518		fprintf(f, "[NULL ipt table name ] assuming mangle ");
519	} else {
520		fprintf(f, "tablename: %s ",
521			(char *) RTA_DATA(tb[TCA_IPT_TABLE]));
522	}
523
524	if (tb[TCA_IPT_HOOK] == NULL) {
525		fprintf(f, "[NULL ipt hook name ]\n ");
526		return -1;
527	} else {
528		__u32 hook;
529		hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
530		fprintf(f, " hook: %s \n", ipthooks[hook]);
531	}
532
533	if (tb[TCA_IPT_TARG] == NULL) {
534		fprintf(f, "\t[NULL ipt target parameters ] \n");
535		return -1;
536	} else {
537		struct iptables_target *m = NULL;
538		t = RTA_DATA(tb[TCA_IPT_TARG]);
539		m = get_target_name(t->u.user.name);
540		if (NULL != m) {
541			if (0 > build_st(m, t)) {
542				fprintf(stderr, " %s error \n", m->name);
543				return -1;
544			}
545
546			opts =
547			    merge_options(opts, m->extra_opts,
548					  &m->option_offset);
549		} else {
550			fprintf(stderr, " failed to find target %s\n\n",
551				t->u.user.name);
552			return -1;
553		}
554		fprintf(f, "\ttarget ");
555		m->print(NULL, m->t, 0);
556		if (tb[TCA_IPT_INDEX] == NULL) {
557			fprintf(f, " [NULL ipt target index ]\n");
558		} else {
559			__u32 index;
560			index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
561			fprintf(f, " \n\tindex %d", index);
562		}
563
564		if (tb[TCA_IPT_CNT]) {
565			struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
566			fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
567		}
568		if (show_stats) {
569			if (tb[TCA_IPT_TM]) {
570				struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
571				print_tm(f,tm);
572			}
573		}
574		fprintf(f, " \n");
575
576	}
577	free_opts(opts);
578
579	return 0;
580}
581
582struct action_util ipt_action_util = {
583        .id = "ipt",
584        .parse_aopt = parse_ipt,
585        .print_aopt = print_ipt,
586};
587
588