m_ipt.c revision a589dcda9cc10c8475db18258e6456c1d9c15371 
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
73xtables_register_target(struct iptables_target *me)
74{
75	me->next = t_list;
76	t_list = me;
77}
78
79void
80exit_tryhelp(int status)
81{
82	fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
83		pname, pname);
84	exit(status);
85}
86
87void
88exit_error(enum exittype status, char *msg, ...)
89{
90	va_list args;
91
92	va_start(args, msg);
93	fprintf(stderr, "%s v%s: ", pname, pversion);
94	vfprintf(stderr, msg, args);
95	va_end(args);
96	fprintf(stderr, "\n");
97	if (status == PARAMETER_PROBLEM)
98		exit_tryhelp(status);
99	if (status == VERSION_PROBLEM)
100		fprintf(stderr,
101			"Perhaps iptables or your kernel needs to be upgraded.\n");
102	exit(status);
103}
104
105/* stolen from iptables 1.2.11
106They should really have them as a library so i can link to them
107Email them next time i remember
108*/
109
110char *
111addr_to_dotted(const struct in_addr *addrp)
112{
113	static char buf[20];
114	const unsigned char *bytep;
115
116	bytep = (const unsigned char *) &(addrp->s_addr);
117	sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
118	return buf;
119}
120
121int string_to_number_ll(const char *s, unsigned long long min,
122			unsigned long long max,
123		 unsigned long long *ret)
124{
125	unsigned long long number;
126	char *end;
127
128	/* Handle hex, octal, etc. */
129	errno = 0;
130	number = strtoull(s, &end, 0);
131	if (*end == '\0' && end != s) {
132		/* we parsed a number, let's see if we want this */
133		if (errno != ERANGE && min <= number && (!max || number <= max)) {
134			*ret = number;
135			return 0;
136		}
137	}
138	return -1;
139}
140
141int string_to_number_l(const char *s, unsigned long min, unsigned long max,
142		       unsigned long *ret)
143{
144	int result;
145	unsigned long long number;
146
147	result = string_to_number_ll(s, min, max, &number);
148	*ret = (unsigned long)number;
149
150	return result;
151}
152
153int string_to_number(const char *s, unsigned int min, unsigned int max,
154		unsigned int *ret)
155{
156	int result;
157	unsigned long number;
158
159	result = string_to_number_l(s, min, max, &number);
160	*ret = (unsigned int)number;
161
162	return result;
163}
164
165static void free_opts(struct option *local_opts)
166{
167	if (local_opts != original_opts) {
168		free(local_opts);
169		opts = original_opts;
170		global_option_offset = 0;
171	}
172}
173
174static struct option *
175merge_options(struct option *oldopts, const struct option *newopts,
176	      unsigned int *option_offset)
177{
178	struct option *merge;
179	unsigned int num_old, num_new, i;
180
181	for (num_old = 0; oldopts[num_old].name; num_old++) ;
182	for (num_new = 0; newopts[num_new].name; num_new++) ;
183
184	*option_offset = global_option_offset + OPTION_OFFSET;
185
186	merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
187	memcpy(merge, oldopts, num_old * sizeof (struct option));
188	for (i = 0; i < num_new; i++) {
189		merge[num_old + i] = newopts[i];
190		merge[num_old + i].val += *option_offset;
191	}
192	memset(merge + num_old + num_new, 0, sizeof (struct option));
193
194	return merge;
195}
196
197static void *
198fw_calloc(size_t count, size_t size)
199{
200	void *p;
201
202	if ((p = (void *) calloc(count, size)) == NULL) {
203		perror("iptables: calloc failed");
204		exit(1);
205	}
206	return p;
207}
208
209static struct iptables_target *
210find_t(char *name)
211{
212	struct iptables_target *m;
213	for (m = t_list; m; m = m->next) {
214		if (strcmp(m->name, name) == 0)
215			return m;
216	}
217
218	return NULL;
219}
220
221static struct iptables_target *
222get_target_name(const char *name)
223{
224	void *handle;
225	char *error;
226	char *new_name, *lname;
227	struct iptables_target *m;
228	char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
229
230	new_name = malloc(strlen(name) + 1);
231	lname = malloc(strlen(name) + 1);
232	if (new_name)
233		memset(new_name, '\0', strlen(name) + 1);
234	else
235		exit_error(PARAMETER_PROBLEM, "get_target_name");
236
237	if (lname)
238		memset(lname, '\0', strlen(name) + 1);
239	else
240		exit_error(PARAMETER_PROBLEM, "get_target_name");
241
242	strcpy(new_name, name);
243	strcpy(lname, name);
244
245	if (isupper(lname[0])) {
246		int i;
247		for (i = 0; i < strlen(name); i++) {
248			lname[i] = tolower(lname[i]);
249		}
250	}
251
252	if (islower(new_name[0])) {
253		int i;
254		for (i = 0; i < strlen(new_name); i++) {
255			new_name[i] = toupper(new_name[i]);
256		}
257	}
258
259	/* try libxt_xx first */
260	sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);
261	handle = dlopen(path, RTLD_LAZY);
262	if (!handle) {
263		/* try libipt_xx next */
264		sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);
265		handle = dlopen(path, RTLD_LAZY);
266
267		if (!handle) {
268			sprintf(path, "%s/libxt_%s.so", lib_dir , lname);
269			handle = dlopen(path, RTLD_LAZY);
270		}
271
272		if (!handle) {
273			sprintf(path, "%s/libipt_%s.so", lib_dir , lname);
274			handle = dlopen(path, RTLD_LAZY);
275		}
276		/* ok, lets give up .. */
277		if (!handle) {
278			fputs(dlerror(), stderr);
279			printf("\n");
280			free(new_name);
281			return NULL;
282		}
283	}
284
285	m = dlsym(handle, new_name);
286	if ((error = dlerror()) != NULL) {
287		m = (struct iptables_target *) dlsym(handle, lname);
288		if ((error = dlerror()) != NULL) {
289			m = find_t(new_name);
290			if (NULL == m) {
291				m = find_t(lname);
292				if (NULL == m) {
293					fputs(error, stderr);
294					fprintf(stderr, "\n");
295					dlclose(handle);
296					free(new_name);
297					return NULL;
298				}
299			}
300		}
301	}
302
303	free(new_name);
304	return m;
305}
306
307
308struct in_addr *dotted_to_addr(const char *dotted)
309{
310	static struct in_addr addr;
311	unsigned char *addrp;
312	char *p, *q;
313	unsigned int onebyte;
314	int i;
315	char buf[20];
316
317	/* copy dotted string, because we need to modify it */
318	strncpy(buf, dotted, sizeof (buf) - 1);
319	addrp = (unsigned char *) &(addr.s_addr);
320
321	p = buf;
322	for (i = 0; i < 3; i++) {
323		if ((q = strchr(p, '.')) == NULL)
324			return (struct in_addr *) NULL;
325
326		*q = '\0';
327		if (string_to_number(p, 0, 255, &onebyte) == -1)
328			return (struct in_addr *) NULL;
329
330		addrp[i] = (unsigned char) onebyte;
331		p = q + 1;
332	}
333
334	/* we've checked 3 bytes, now we check the last one */
335	if (string_to_number(p, 0, 255, &onebyte) == -1)
336		return (struct in_addr *) NULL;
337
338	addrp[3] = (unsigned char) onebyte;
339
340	return &addr;
341}
342
343static void set_revision(char *name, u_int8_t revision)
344{
345	/* Old kernel sources don't have ".revision" field,
346	*  but we stole a byte from name. */
347	name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
348	name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
349}
350
351/*
352 * we may need to check for version mismatch
353*/
354int
355build_st(struct iptables_target *target, struct ipt_entry_target *t)
356{
357	unsigned int nfcache = 0;
358
359	if (target) {
360		size_t size;
361
362		size =
363		    IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
364
365		if (NULL == t) {
366			target->t = fw_calloc(1, size);
367			target->t->u.target_size = size;
368
369			if (target->init != NULL)
370				target->init(target->t, &nfcache);
371			set_revision(target->t->u.user.name, target->revision);
372		} else {
373			target->t = t;
374		}
375		strcpy(target->t->u.user.name, target->name);
376		return 0;
377	}
378
379	return -1;
380}
381
382static int parse_ipt(struct action_util *a,int *argc_p,
383		     char ***argv_p, int tca_id, struct nlmsghdr *n)
384{
385	struct iptables_target *m = NULL;
386	struct ipt_entry fw;
387	struct rtattr *tail;
388	int c;
389	int rargc = *argc_p;
390	char **argv = *argv_p;
391	int argc = 0, iargc = 0;
392	char k[16];
393	int res = -1;
394	int size = 0;
395	int iok = 0, ok = 0;
396	__u32 hook = 0, index = 0;
397	res = 0;
398
399	lib_dir = getenv("IPTABLES_LIB_DIR");
400	if (!lib_dir)
401		lib_dir = IPT_LIB_DIR;
402
403	{
404		int i;
405		for (i = 0; i < rargc; i++) {
406			if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
407				break;
408			}
409		}
410		iargc = argc = i;
411	}
412
413	if (argc <= 2) {
414		fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
415		return -1;
416	}
417
418	while (1) {
419		c = getopt_long(argc, argv, "j:", opts, NULL);
420		if (c == -1)
421			break;
422		switch (c) {
423		case 'j':
424			m = get_target_name(optarg);
425			if (NULL != m) {
426
427				if (0 > build_st(m, NULL)) {
428					printf(" %s error \n", m->name);
429					return -1;
430				}
431				opts =
432				    merge_options(opts, m->extra_opts,
433						  &m->option_offset);
434			} else {
435				fprintf(stderr," failed to find target %s\n\n", optarg);
436				return -1;
437			}
438			ok++;
439			break;
440
441		default:
442			memset(&fw, 0, sizeof (fw));
443			if (m) {
444				m->parse(c - m->option_offset, argv, 0,
445					 &m->tflags, NULL, &m->t);
446			} else {
447				fprintf(stderr," failed to find target %s\n\n", optarg);
448				return -1;
449
450			}
451			ok++;
452			break;
453
454		}
455	}
456
457	if (iargc > optind) {
458		if (matches(argv[optind], "index") == 0) {
459			if (get_u32(&index, argv[optind + 1], 10)) {
460				fprintf(stderr, "Illegal \"index\"\n");
461				free_opts(opts);
462				return -1;
463			}
464			iok++;
465
466			optind += 2;
467		}
468	}
469
470	if (!ok && !iok) {
471		fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
472		return -1;
473	}
474
475	/* check that we passed the correct parameters to the target */
476	if (m)
477		m->final_check(m->tflags);
478
479	{
480		struct tcmsg *t = NLMSG_DATA(n);
481		if (t->tcm_parent != TC_H_ROOT
482		    && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
483			hook = NF_IP_PRE_ROUTING;
484		} else {
485			hook = NF_IP_POST_ROUTING;
486		}
487	}
488
489	tail = NLMSG_TAIL(n);
490	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
491	fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
492	fprintf(stdout, "\ttarget: ");
493
494	if (m)
495		m->print(NULL, m->t, 0);
496	fprintf(stdout, " index %d\n", index);
497
498	if (strlen(tname) > 16) {
499		size = 16;
500		k[15] = 0;
501	} else {
502		size = 1 + strlen(tname);
503	}
504	strncpy(k, tname, size);
505
506	addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
507	addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
508	addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
509	if (m)
510		addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
511	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
512
513	argc -= optind;
514	argv += optind;
515	*argc_p = rargc - iargc;
516	*argv_p = argv;
517
518	optind = 0;
519	free_opts(opts);
520	/* Clear flags if target will be used again */
521        m->tflags=0;
522        m->used=0;
523	/* Free allocated memory */
524        if (m->t)
525            free(m->t);
526
527
528	return 0;
529
530}
531
532static int
533print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
534{
535	struct rtattr *tb[TCA_IPT_MAX + 1];
536	struct ipt_entry_target *t = NULL;
537
538	if (arg == NULL)
539		return -1;
540
541	lib_dir = getenv("IPTABLES_LIB_DIR");
542	if (!lib_dir)
543		lib_dir = IPT_LIB_DIR;
544
545	parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
546
547	if (tb[TCA_IPT_TABLE] == NULL) {
548		fprintf(f, "[NULL ipt table name ] assuming mangle ");
549	} else {
550		fprintf(f, "tablename: %s ",
551			(char *) RTA_DATA(tb[TCA_IPT_TABLE]));
552	}
553
554	if (tb[TCA_IPT_HOOK] == NULL) {
555		fprintf(f, "[NULL ipt hook name ]\n ");
556		return -1;
557	} else {
558		__u32 hook;
559		hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
560		fprintf(f, " hook: %s \n", ipthooks[hook]);
561	}
562
563	if (tb[TCA_IPT_TARG] == NULL) {
564		fprintf(f, "\t[NULL ipt target parameters ] \n");
565		return -1;
566	} else {
567		struct iptables_target *m = NULL;
568		t = RTA_DATA(tb[TCA_IPT_TARG]);
569		m = get_target_name(t->u.user.name);
570		if (NULL != m) {
571			if (0 > build_st(m, t)) {
572				fprintf(stderr, " %s error \n", m->name);
573				return -1;
574			}
575
576			opts =
577			    merge_options(opts, m->extra_opts,
578					  &m->option_offset);
579		} else {
580			fprintf(stderr, " failed to find target %s\n\n",
581				t->u.user.name);
582			return -1;
583		}
584		fprintf(f, "\ttarget ");
585		m->print(NULL, m->t, 0);
586		if (tb[TCA_IPT_INDEX] == NULL) {
587			fprintf(f, " [NULL ipt target index ]\n");
588		} else {
589			__u32 index;
590			index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
591			fprintf(f, " \n\tindex %d", index);
592		}
593
594		if (tb[TCA_IPT_CNT]) {
595			struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
596			fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
597		}
598		if (show_stats) {
599			if (tb[TCA_IPT_TM]) {
600				struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
601				print_tm(f,tm);
602			}
603		}
604		fprintf(f, " \n");
605
606	}
607	free_opts(opts);
608
609	return 0;
610}
611
612struct action_util ipt_action_util = {
613        .id = "ipt",
614        .parse_aopt = parse_ipt,
615        .print_aopt = print_ipt,
616};
617
618