m_ipt.c revision 65840e27ba0ad201fbcb143d38f94197963645d5 
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 unsigned int global_option_offset = 0;
73#define OPTION_OFFSET 256
74
75
76void
77register_target(struct iptables_target *me)
78{
79/*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
80*/
81	me->next = t_list;
82	t_list = me;
83
84}
85
86void
87exit_tryhelp(int status)
88{
89	fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
90		pname, pname);
91	exit(status);
92}
93
94void
95exit_error(enum exittype status, char *msg, ...)
96{
97	va_list args;
98
99	va_start(args, msg);
100	fprintf(stderr, "%s v%s: ", pname, pversion);
101	vfprintf(stderr, msg, args);
102	va_end(args);
103	fprintf(stderr, "\n");
104	if (status == PARAMETER_PROBLEM)
105		exit_tryhelp(status);
106	if (status == VERSION_PROBLEM)
107		fprintf(stderr,
108			"Perhaps iptables or your kernel needs to be upgraded.\n");
109	exit(status);
110}
111
112/* stolen from iptables 1.2.11
113They should really have them as a library so i can link to them
114Email them next time i remember
115*/
116
117char *
118addr_to_dotted(const struct in_addr *addrp)
119{
120	static char buf[20];
121	const unsigned char *bytep;
122
123	bytep = (const unsigned char *) &(addrp->s_addr);
124	sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
125	return buf;
126}
127
128int string_to_number_ll(const char *s, unsigned long long min,
129			unsigned long long max,
130		 unsigned long long *ret)
131{
132	unsigned long long number;
133	char *end;
134
135	/* Handle hex, octal, etc. */
136	errno = 0;
137	number = strtoull(s, &end, 0);
138	if (*end == '\0' && end != s) {
139		/* we parsed a number, let's see if we want this */
140		if (errno != ERANGE && min <= number && (!max || number <= max)) {
141			*ret = number;
142			return 0;
143		}
144	}
145	return -1;
146}
147
148int string_to_number_l(const char *s, unsigned long min, unsigned long max,
149		       unsigned long *ret)
150{
151	int result;
152	unsigned long long number;
153
154	result = string_to_number_ll(s, min, max, &number);
155	*ret = (unsigned long)number;
156
157	return result;
158}
159
160int string_to_number(const char *s, unsigned int min, unsigned int max,
161		unsigned int *ret)
162{
163	int result;
164	unsigned long number;
165
166	result = string_to_number_l(s, min, max, &number);
167	*ret = (unsigned int)number;
168
169	return result;
170}
171
172static struct option *
173copy_options(struct option *oldopts)
174{
175	struct option *merge;
176	unsigned int num_old;
177	for (num_old = 0; oldopts[num_old].name; num_old++) ;
178	merge = malloc(sizeof (struct option) * (num_old + 1));
179	if (NULL == merge)
180		return NULL;
181	memcpy(merge, oldopts, num_old * sizeof (struct option));
182	memset(merge + num_old, 0, sizeof (struct option));
183	return merge;
184}
185
186static struct option *
187merge_options(struct option *oldopts, const struct option *newopts,
188	      unsigned int *option_offset)
189{
190	struct option *merge;
191	unsigned int num_old, num_new, i;
192
193	for (num_old = 0; oldopts[num_old].name; num_old++) ;
194	for (num_new = 0; newopts[num_new].name; num_new++) ;
195
196	*option_offset = global_option_offset + OPTION_OFFSET;
197
198	merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
199	memcpy(merge, oldopts, num_old * sizeof (struct option));
200	for (i = 0; i < num_new; i++) {
201		merge[num_old + i] = newopts[i];
202		merge[num_old + i].val += *option_offset;
203	}
204	memset(merge + num_old + num_new, 0, sizeof (struct option));
205
206	return merge;
207}
208
209static void *
210fw_calloc(size_t count, size_t size)
211{
212	void *p;
213
214	if ((p = (void *) calloc(count, size)) == NULL) {
215		perror("iptables: calloc failed");
216		exit(1);
217	}
218	return p;
219}
220
221static struct iptables_target *
222find_t(char *name)
223{
224	struct iptables_target *m;
225	for (m = t_list; m; m = m->next) {
226		if (strcmp(m->name, name) == 0)
227			return m;
228	}
229
230	return NULL;
231}
232
233static struct iptables_target *
234get_target_name(char *name)
235{
236	void *handle;
237	char *error;
238	char *new_name, *lname;
239	struct iptables_target *m;
240
241	char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
242
243	new_name = malloc(strlen(name) + 1);
244	lname = malloc(strlen(name) + 1);
245	if (new_name)
246		memset(new_name, '\0', strlen(name) + 1);
247	else
248		exit_error(PARAMETER_PROBLEM, "get_target_name");
249
250	if (lname)
251		memset(lname, '\0', strlen(name) + 1);
252	else
253		exit_error(PARAMETER_PROBLEM, "get_target_name");
254
255	strcpy(new_name, name);
256	strcpy(lname, name);
257
258	if (isupper(lname[0])) {
259		int i;
260		for (i = 0; i < strlen(name); i++) {
261			lname[i] = tolower(lname[i]);
262		}
263	}
264
265	if (islower(new_name[0])) {
266		int i;
267		for (i = 0; i < strlen(new_name); i++) {
268			new_name[i] = toupper(new_name[i]);
269		}
270	}
271
272	sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
273	handle = dlopen(path, RTLD_LAZY);
274	if (!handle) {
275		sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
276		handle = dlopen(path, RTLD_LAZY);
277		if (!handle) {
278			fputs(dlerror(), stderr);
279			printf("\n");
280			return NULL;
281		}
282	}
283
284	m = dlsym(handle, new_name);
285	if ((error = dlerror()) != NULL) {
286		m = (struct iptables_target *) dlsym(handle, lname);
287		if ((error = dlerror()) != NULL) {
288			m = find_t(new_name);
289			if (NULL == m) {
290				m = find_t(lname);
291				if (NULL == m) {
292					fputs(error, stderr);
293					fprintf(stderr, "\n");
294					dlclose(handle);
295					return NULL;
296				}
297			}
298		}
299	}
300
301	return m;
302}
303
304
305struct in_addr *dotted_to_addr(const char *dotted)
306{
307	static struct in_addr addr;
308	unsigned char *addrp;
309	char *p, *q;
310	unsigned int onebyte;
311	int i;
312	char buf[20];
313
314	/* copy dotted string, because we need to modify it */
315	strncpy(buf, dotted, sizeof (buf) - 1);
316	addrp = (unsigned char *) &(addr.s_addr);
317
318	p = buf;
319	for (i = 0; i < 3; i++) {
320		if ((q = strchr(p, '.')) == NULL)
321			return (struct in_addr *) NULL;
322
323		*q = '\0';
324		if (string_to_number(p, 0, 255, &onebyte) == -1)
325			return (struct in_addr *) NULL;
326
327		addrp[i] = (unsigned char) onebyte;
328		p = q + 1;
329	}
330
331	/* we've checked 3 bytes, now we check the last one */
332	if (string_to_number(p, 0, 255, &onebyte) == -1)
333		return (struct in_addr *) NULL;
334
335	addrp[3] = (unsigned char) onebyte;
336
337	return &addr;
338}
339
340int
341build_st(struct iptables_target *target, struct ipt_entry_target *t)
342{
343	unsigned int nfcache = 0;
344
345	if (target) {
346		size_t size;
347
348		size =
349		    IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
350
351		if (NULL == t) {
352			target->t = fw_calloc(1, size);
353			target->init(target->t, &nfcache);
354			target->t->u.target_size = size;
355		} else {
356			target->t = t;
357		}
358		strcpy(target->t->u.user.name, target->name);
359		return 0;
360	}
361
362	return -1;
363}
364
365static int parse_ipt(struct action_util *a,int *argc_p,
366		     char ***argv_p, int tca_id, struct nlmsghdr *n)
367{
368	struct iptables_target *m = NULL;
369	struct ipt_entry fw;
370	struct rtattr *tail;
371	int c;
372	int rargc = *argc_p;
373	char **argv = *argv_p;
374	struct option *opts;
375	int argc = 0, iargc = 0;
376	char k[16];
377	int res = -1;
378	int size = 0;
379	int iok = 0, ok = 0;
380	__u32 hook = 0, index = 0;
381	res = 0;
382
383	{
384		int i;
385		for (i = 0; i < rargc; i++) {
386			if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
387				break;
388			}
389		}
390		iargc = argc = i;
391	}
392
393	if (argc <= 2) {
394		fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
395		return -1;
396	}
397
398	opts = copy_options(original_opts);
399
400	if (NULL == opts)
401		return -1;
402
403	while (1) {
404		c = getopt_long(argc, argv, "j:", opts, NULL);
405		if (c == -1)
406			break;
407		switch (c) {
408		case 'j':
409			m = get_target_name(optarg);
410			if (NULL != m) {
411
412				if (0 > build_st(m, NULL)) {
413					printf(" %s error \n", m->name);
414					return -1;
415				}
416				opts =
417				    merge_options(opts, m->extra_opts,
418						  &m->option_offset);
419			} else {
420				fprintf(stderr," failed to find target %s\n\n", optarg);
421				return -1;
422			}
423			ok++;
424			break;
425
426		default:
427			memset(&fw, 0, sizeof (fw));
428			if (m) {
429				unsigned int fake_flags = 0;
430				m->parse(c - m->option_offset, argv, 0,
431					 &fake_flags, NULL, &m->t);
432			} else {
433				fprintf(stderr," failed to find target %s\n\n", optarg);
434				return -1;
435
436			}
437			ok++;
438
439			/*m->final_check(m->t); -- Is this necessary?
440			** useful when theres depencies
441			** eg ipt_TCPMSS.c has have the TCP match loaded
442			** before this can be used;
443			**  also seems the ECN target needs it
444			*/
445
446			break;
447
448		}
449	}
450
451	if (iargc > optind) {
452		if (matches(argv[optind], "index") == 0) {
453			if (get_u32(&index, argv[optind + 1], 10)) {
454				fprintf(stderr, "Illegal \"index\"\n");
455				return -1;
456			}
457			iok++;
458
459			optind += 2;
460		}
461	}
462
463	if (!ok && !iok) {
464		fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
465		return -1;
466	}
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
509	return 0;
510
511}
512
513static int
514print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
515{
516	struct rtattr *tb[TCA_IPT_MAX + 1];
517	struct ipt_entry_target *t = NULL;
518	struct option *opts;
519
520	if (arg == NULL)
521		return -1;
522
523	opts = copy_options(original_opts);
524
525	if (NULL == opts)
526		return -1;
527
528	parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
529
530	if (tb[TCA_IPT_TABLE] == NULL) {
531		fprintf(f, "[NULL ipt table name ] assuming mangle ");
532	} else {
533		fprintf(f, "tablename: %s ",
534			(char *) RTA_DATA(tb[TCA_IPT_TABLE]));
535	}
536
537	if (tb[TCA_IPT_HOOK] == NULL) {
538		fprintf(f, "[NULL ipt hook name ]\n ");
539		return -1;
540	} else {
541		__u32 hook;
542		hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
543		fprintf(f, " hook: %s \n", ipthooks[hook]);
544	}
545
546	if (tb[TCA_IPT_TARG] == NULL) {
547		fprintf(f, "\t[NULL ipt target parameters ] \n");
548		return -1;
549	} else {
550		struct iptables_target *m = NULL;
551		t = RTA_DATA(tb[TCA_IPT_TARG]);
552		m = get_target_name(t->u.user.name);
553		if (NULL != m) {
554			if (0 > build_st(m, t)) {
555				fprintf(stderr, " %s error \n", m->name);
556				return -1;
557			}
558
559			opts =
560			    merge_options(opts, m->extra_opts,
561					  &m->option_offset);
562		} else {
563			fprintf(stderr, " failed to find target %s\n\n",
564				t->u.user.name);
565			return -1;
566		}
567		fprintf(f, "\ttarget ");
568		m->print(NULL, m->t, 0);
569		if (tb[TCA_IPT_INDEX] == NULL) {
570			fprintf(f, " [NULL ipt target index ]\n");
571		} else {
572			__u32 index;
573			index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
574			fprintf(f, " \n\tindex %d", index);
575		}
576
577		if (tb[TCA_IPT_CNT]) {
578			struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
579			fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
580		}
581		if (show_stats) {
582			if (tb[TCA_IPT_TM]) {
583				struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
584				print_tm(f,tm);
585			}
586		}
587		fprintf(f, " \n");
588
589	}
590
591	return 0;
592}
593
594struct action_util ipt_action_util = {
595        .id = "ipt",
596        .parse_aopt = parse_ipt,
597        .print_aopt = print_ipt,
598};
599
600