m_ipt.c revision ae665a522bd46bea44c5ea84c89c8b1731954170 
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 * TODO: bad bad hardcoding IPT_LIB_DIR and PROC_SYS_MODPROBE
13 *
14*/
15
16#include <syslog.h>
17#include <sys/socket.h>
18#include <netinet/in.h>
19#include <arpa/inet.h>
20#include <iptables.h>
21#include <linux/netfilter_ipv4/ip_tables.h>
22#include "utils.h"
23#include "tc_util.h"
24#include <linux/tc_act/tc_ipt.h>
25#include <stdio.h>
26#include <dlfcn.h>
27#include <getopt.h>
28#include <errno.h>
29#include <string.h>
30#include <netdb.h>
31#include <stdlib.h>
32#include <ctype.h>
33#include <stdarg.h>
34#include <limits.h>
35#include <unistd.h>
36#include <fcntl.h>
37#include <sys/wait.h>
38
39const char *pname = "tc-ipt";
40const char *tname = "mangle";
41const char *pversion = "0.1";
42
43#ifndef TRUE
44#define TRUE 1
45#endif
46#ifndef FALSE
47#define FALSE 0
48#endif
49
50#ifndef IPT_LIB_DIR
51#define IPT_LIB_DIR "/usr/local/lib/iptables"
52#endif
53
54#ifndef PROC_SYS_MODPROBE
55#define PROC_SYS_MODPROBE "/proc/sys/kernel/modprobe"
56#endif
57
58static const char *ipthooks[] = {
59	"NF_IP_PRE_ROUTING",
60	"NF_IP_LOCAL_IN",
61	"NF_IP_FORWARD",
62	"NF_IP_LOCAL_OUT",
63	"NF_IP_POST_ROUTING",
64};
65
66static struct option original_opts[] = {
67	{"jump", 1, 0, 'j'},
68	{0, 0, 0, 0}
69};
70
71static struct iptables_target *t_list = NULL;
72static struct option *opts = original_opts;
73static unsigned int global_option_offset = 0;
74#define OPTION_OFFSET 256
75
76
77void
78register_target(struct iptables_target *me)
79{
80/*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
81*/
82	me->next = t_list;
83	t_list = me;
84
85}
86
87void
88exit_tryhelp(int status)
89{
90	fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
91		pname, pname);
92	exit(status);
93}
94
95void
96exit_error(enum exittype status, char *msg, ...)
97{
98	va_list args;
99
100	va_start(args, msg);
101	fprintf(stderr, "%s v%s: ", pname, pversion);
102	vfprintf(stderr, msg, args);
103	va_end(args);
104	fprintf(stderr, "\n");
105	if (status == PARAMETER_PROBLEM)
106		exit_tryhelp(status);
107	if (status == VERSION_PROBLEM)
108		fprintf(stderr,
109			"Perhaps iptables or your kernel needs to be upgraded.\n");
110	exit(status);
111}
112
113/* stolen from iptables 1.2.11
114They should really have them as a library so i can link to them
115Email them next time i remember
116*/
117
118char *
119addr_to_dotted(const struct in_addr *addrp)
120{
121	static char buf[20];
122	const unsigned char *bytep;
123
124	bytep = (const unsigned char *) &(addrp->s_addr);
125	sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
126	return buf;
127}
128
129int string_to_number_ll(const char *s, unsigned long long min,
130			unsigned long long max,
131		 unsigned long long *ret)
132{
133	unsigned long long number;
134	char *end;
135
136	/* Handle hex, octal, etc. */
137	errno = 0;
138	number = strtoull(s, &end, 0);
139	if (*end == '\0' && end != s) {
140		/* we parsed a number, let's see if we want this */
141		if (errno != ERANGE && min <= number && (!max || number <= max)) {
142			*ret = number;
143			return 0;
144		}
145	}
146	return -1;
147}
148
149int string_to_number_l(const char *s, unsigned long min, unsigned long max,
150		       unsigned long *ret)
151{
152	int result;
153	unsigned long long number;
154
155	result = string_to_number_ll(s, min, max, &number);
156	*ret = (unsigned long)number;
157
158	return result;
159}
160
161int string_to_number(const char *s, unsigned int min, unsigned int max,
162		unsigned int *ret)
163{
164	int result;
165	unsigned long number;
166
167	result = string_to_number_l(s, min, max, &number);
168	*ret = (unsigned int)number;
169
170	return result;
171}
172
173static void free_opts(struct option *opts)
174{
175	if (opts != original_opts) {
176		free(opts);
177		opts = original_opts;
178		global_option_offset = 0;
179	}
180}
181
182static struct option *
183merge_options(struct option *oldopts, const struct option *newopts,
184	      unsigned int *option_offset)
185{
186	struct option *merge;
187	unsigned int num_old, num_new, i;
188
189	for (num_old = 0; oldopts[num_old].name; num_old++) ;
190	for (num_new = 0; newopts[num_new].name; num_new++) ;
191
192	*option_offset = global_option_offset + OPTION_OFFSET;
193
194	merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
195	memcpy(merge, oldopts, num_old * sizeof (struct option));
196	for (i = 0; i < num_new; i++) {
197		merge[num_old + i] = newopts[i];
198		merge[num_old + i].val += *option_offset;
199	}
200	memset(merge + num_old + num_new, 0, sizeof (struct option));
201
202	return merge;
203}
204
205static void *
206fw_calloc(size_t count, size_t size)
207{
208	void *p;
209
210	if ((p = (void *) calloc(count, size)) == NULL) {
211		perror("iptables: calloc failed");
212		exit(1);
213	}
214	return p;
215}
216
217static struct iptables_target *
218find_t(char *name)
219{
220	struct iptables_target *m;
221	for (m = t_list; m; m = m->next) {
222		if (strcmp(m->name, name) == 0)
223			return m;
224	}
225
226	return NULL;
227}
228
229static struct iptables_target *
230get_target_name(char *name)
231{
232	void *handle;
233	char *error;
234	char *new_name, *lname;
235	struct iptables_target *m;
236
237	char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
238
239	new_name = malloc(strlen(name) + 1);
240	lname = malloc(strlen(name) + 1);
241	if (new_name)
242		memset(new_name, '\0', strlen(name) + 1);
243	else
244		exit_error(PARAMETER_PROBLEM, "get_target_name");
245
246	if (lname)
247		memset(lname, '\0', strlen(name) + 1);
248	else
249		exit_error(PARAMETER_PROBLEM, "get_target_name");
250
251	strcpy(new_name, name);
252	strcpy(lname, name);
253
254	if (isupper(lname[0])) {
255		int i;
256		for (i = 0; i < strlen(name); i++) {
257			lname[i] = tolower(lname[i]);
258		}
259	}
260
261	if (islower(new_name[0])) {
262		int i;
263		for (i = 0; i < strlen(new_name); i++) {
264			new_name[i] = toupper(new_name[i]);
265		}
266	}
267
268	sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
269	handle = dlopen(path, RTLD_LAZY);
270	if (!handle) {
271		sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
272		handle = dlopen(path, RTLD_LAZY);
273		if (!handle) {
274			fputs(dlerror(), stderr);
275			printf("\n");
276			return NULL;
277		}
278	}
279
280	m = dlsym(handle, new_name);
281	if ((error = dlerror()) != NULL) {
282		m = (struct iptables_target *) dlsym(handle, lname);
283		if ((error = dlerror()) != NULL) {
284			m = find_t(new_name);
285			if (NULL == m) {
286				m = find_t(lname);
287				if (NULL == m) {
288					fputs(error, stderr);
289					fprintf(stderr, "\n");
290					dlclose(handle);
291					return NULL;
292				}
293			}
294		}
295	}
296
297	return m;
298}
299
300
301struct in_addr *dotted_to_addr(const char *dotted)
302{
303	static struct in_addr addr;
304	unsigned char *addrp;
305	char *p, *q;
306	unsigned int onebyte;
307	int i;
308	char buf[20];
309
310	/* copy dotted string, because we need to modify it */
311	strncpy(buf, dotted, sizeof (buf) - 1);
312	addrp = (unsigned char *) &(addr.s_addr);
313
314	p = buf;
315	for (i = 0; i < 3; i++) {
316		if ((q = strchr(p, '.')) == NULL)
317			return (struct in_addr *) NULL;
318
319		*q = '\0';
320		if (string_to_number(p, 0, 255, &onebyte) == -1)
321			return (struct in_addr *) NULL;
322
323		addrp[i] = (unsigned char) onebyte;
324		p = q + 1;
325	}
326
327	/* we've checked 3 bytes, now we check the last one */
328	if (string_to_number(p, 0, 255, &onebyte) == -1)
329		return (struct in_addr *) NULL;
330
331	addrp[3] = (unsigned char) onebyte;
332
333	return &addr;
334}
335
336static void set_revision(char *name, u_int8_t revision)
337{
338	/* Old kernel sources don't have ".revision" field,
339	*  but we stole a byte from name. */
340	name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
341	name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
342}
343
344/*
345 * we may need to check for version mismatch
346*/
347int
348build_st(struct iptables_target *target, struct ipt_entry_target *t)
349{
350	unsigned int nfcache = 0;
351
352	if (target) {
353		size_t size;
354
355		size =
356		    IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
357
358		if (NULL == t) {
359			target->t = fw_calloc(1, size);
360			target->t->u.target_size = size;
361
362			if (target->init != NULL)
363				target->init(target->t, &nfcache);
364			set_revision(target->t->u.user.name, target->revision);
365		} else {
366			target->t = t;
367		}
368		strcpy(target->t->u.user.name, target->name);
369		return 0;
370	}
371
372	return -1;
373}
374
375static int parse_ipt(struct action_util *a,int *argc_p,
376		     char ***argv_p, int tca_id, struct nlmsghdr *n)
377{
378	struct iptables_target *m = NULL;
379	struct ipt_entry fw;
380	struct rtattr *tail;
381	int c;
382	int rargc = *argc_p;
383	char **argv = *argv_p;
384	int argc = 0, iargc = 0;
385	char k[16];
386	int res = -1;
387	int size = 0;
388	int iok = 0, ok = 0;
389	__u32 hook = 0, index = 0;
390	res = 0;
391
392	{
393		int i;
394		for (i = 0; i < rargc; i++) {
395			if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
396				break;
397			}
398		}
399		iargc = argc = i;
400	}
401
402	if (argc <= 2) {
403		fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
404		return -1;
405	}
406
407	while (1) {
408		c = getopt_long(argc, argv, "j:", opts, NULL);
409		if (c == -1)
410			break;
411		switch (c) {
412		case 'j':
413			m = get_target_name(optarg);
414			if (NULL != m) {
415
416				if (0 > build_st(m, NULL)) {
417					printf(" %s error \n", m->name);
418					return -1;
419				}
420				opts =
421				    merge_options(opts, m->extra_opts,
422						  &m->option_offset);
423			} else {
424				fprintf(stderr," failed to find target %s\n\n", optarg);
425				return -1;
426			}
427			ok++;
428			break;
429
430		default:
431			memset(&fw, 0, sizeof (fw));
432			if (m) {
433				m->parse(c - m->option_offset, argv, 0,
434					 &m->tflags, NULL, &m->t);
435			} else {
436				fprintf(stderr," failed to find target %s\n\n", optarg);
437				return -1;
438
439			}
440			ok++;
441			break;
442
443		}
444	}
445
446	if (iargc > optind) {
447		if (matches(argv[optind], "index") == 0) {
448			if (get_u32(&index, argv[optind + 1], 10)) {
449				fprintf(stderr, "Illegal \"index\"\n");
450				free_opts(opts);
451				return -1;
452			}
453			iok++;
454
455			optind += 2;
456		}
457	}
458
459	if (!ok && !iok) {
460		fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
461		return -1;
462	}
463
464	/* check that we passed the correct parameters to the target */
465	if (m)
466		m->final_check(m->tflags);
467
468	{
469		struct tcmsg *t = NLMSG_DATA(n);
470		if (t->tcm_parent != TC_H_ROOT
471		    && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
472			hook = NF_IP_PRE_ROUTING;
473		} else {
474			hook = NF_IP_POST_ROUTING;
475		}
476	}
477
478	tail = NLMSG_TAIL(n);
479	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
480	fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
481	fprintf(stdout, "\ttarget: ");
482
483	if (m)
484		m->print(NULL, m->t, 0);
485	fprintf(stdout, " index %d\n", index);
486
487	if (strlen(tname) > 16) {
488		size = 16;
489		k[15] = 0;
490	} else {
491		size = 1 + strlen(tname);
492	}
493	strncpy(k, tname, size);
494
495	addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
496	addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
497	addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
498	if (m)
499		addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
500	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
501
502	argc -= optind;
503	argv += optind;
504	*argc_p = rargc - iargc;
505	*argv_p = argv;
506
507	optind = 1;
508	free_opts(opts);
509
510	return 0;
511
512}
513
514static int
515print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
516{
517	struct rtattr *tb[TCA_IPT_MAX + 1];
518	struct ipt_entry_target *t = NULL;
519
520	if (arg == NULL)
521		return -1;
522
523	parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
524
525	if (tb[TCA_IPT_TABLE] == NULL) {
526		fprintf(f, "[NULL ipt table name ] assuming mangle ");
527	} else {
528		fprintf(f, "tablename: %s ",
529			(char *) RTA_DATA(tb[TCA_IPT_TABLE]));
530	}
531
532	if (tb[TCA_IPT_HOOK] == NULL) {
533		fprintf(f, "[NULL ipt hook name ]\n ");
534		return -1;
535	} else {
536		__u32 hook;
537		hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
538		fprintf(f, " hook: %s \n", ipthooks[hook]);
539	}
540
541	if (tb[TCA_IPT_TARG] == NULL) {
542		fprintf(f, "\t[NULL ipt target parameters ] \n");
543		return -1;
544	} else {
545		struct iptables_target *m = NULL;
546		t = RTA_DATA(tb[TCA_IPT_TARG]);
547		m = get_target_name(t->u.user.name);
548		if (NULL != m) {
549			if (0 > build_st(m, t)) {
550				fprintf(stderr, " %s error \n", m->name);
551				return -1;
552			}
553
554			opts =
555			    merge_options(opts, m->extra_opts,
556					  &m->option_offset);
557		} else {
558			fprintf(stderr, " failed to find target %s\n\n",
559				t->u.user.name);
560			return -1;
561		}
562		fprintf(f, "\ttarget ");
563		m->print(NULL, m->t, 0);
564		if (tb[TCA_IPT_INDEX] == NULL) {
565			fprintf(f, " [NULL ipt target index ]\n");
566		} else {
567			__u32 index;
568			index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
569			fprintf(f, " \n\tindex %d", index);
570		}
571
572		if (tb[TCA_IPT_CNT]) {
573			struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
574			fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
575		}
576		if (show_stats) {
577			if (tb[TCA_IPT_TM]) {
578				struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
579				print_tm(f,tm);
580			}
581		}
582		fprintf(f, " \n");
583
584	}
585	free_opts(opts);
586
587	return 0;
588}
589
590struct action_util ipt_action_util = {
591        .id = "ipt",
592        .parse_aopt = parse_ipt,
593        .print_aopt = print_ipt,
594};
595
596